WorldWideScience

Sample records for radiation flux density

  1. Monitoring of dose rates and radiation flux density in working rooms

    International Nuclear Information System (INIS)

    Krajtor, S.N.

    1980-01-01

    The problems of determining the neutron field characteristics (dose equivalent rate and flux density) in relation to the environmental monitoring by radiation protection services. The measurement devices used for measuring dose equivalent rate and neutron flux density RUS-U8 multi-purpose scintillation radiometer and RUP-1 multi-purpose transportable radiometer as well as measurement technique are described. Recommendations are given for checking measuring devices calibration, registering measurement results [ru

  2. Microsystem for remote sensing of high energy radiation with associated extremely low photon flux densities

    Science.gov (United States)

    Otten, A.; Jain, V. K.

    2015-08-01

    This paper presents a microsystem for remote sensing of high energy radiation in extremely low flux density conditions. With wide deployment in mind, potential applications range from nuclear non-proliferation, to hospital radiation-safety. The daunting challenge is the low level of photon flux densities - emerging from a Scintillation Crystal (SC) on to a ~1 mm-square detector, which are a factor of 10000 or so lower than those acceptable to recently reported photonic chips (including `single-photon detection' chips), due to a combination of low Lux, small detector size, and short duration SC output pulses - on the order of 1 μs. These challenges are attempted to be overcome by the design of an innovative `System on a Chip' type microchip, with high detector sensitivity, and effective coupling from the SC to the photodetector. The microchip houses a tiny n+ diff p-epi photodiode (PD) as well as the associated analog amplification and other related circuitry, all fabricated in 0.5micron, 3-metal 2-poly CMOS technology. The amplification, together with pulse-shaping of the photocurrent-induced voltage signal, is achieved through a tandem of two capacitively coupled, double-cascode amplifiers. Included in the paper are theoretical estimates and experimental results.

  3. Conical electromagnetic radiation flux concentrator

    Science.gov (United States)

    Miller, E. R.

    1972-01-01

    Concentrator provides method of concentrating a beam of electromagnetic radiation into a smaller beam, presenting a higher flux density. Smaller beam may be made larger by sending radiation through the device in the reverse direction.

  4. Solar Modulation of Inner Trapped Belt Radiation Flux as a Function of Atmospheric Density

    Science.gov (United States)

    Lodhi, M. A. K.

    2005-01-01

    No simple algorithm seems to exist for calculating proton fluxes and lifetimes in the Earth's inner, trapped radiation belt throughout the solar cycle. Most models of the inner trapped belt in use depend upon AP8 which only describes the radiation environment at solar maximum and solar minimum in Cycle 20. One exception is NOAAPRO which incorporates flight data from the TIROS/NOAA polar orbiting spacecraft. The present study discloses yet another, simple formulation for approximating proton fluxes at any time in a given solar cycle, in particular between solar maximum and solar minimum. It is derived from AP8 using a regression algorithm technique from nuclear physics. From flux and its time integral fluence, one can then approximate dose rate and its time integral dose.

  5. Influence of the flux density on the radiation damage of bipolar silicon transistors by protons and electrons

    International Nuclear Information System (INIS)

    Bannikov, Y.; Gorin, B.; Kozhevnikov, V.; Mikhnovich, V.; Gusev, L.

    1981-01-01

    It was found experimentally that the radiation damage of bipolar n-p-n transistors increased by a factor of 8--12 when the proton flux density was reduced from 4.07 x 10 10 to 2.5 x 10 7 cm -2 sec -1 . In the case of p-n-p transistors the effect was opposite: there was a reduction in the radiation damage by a factor of 2--3 when the dose rate was lowered between the same limits. A similar effect was observed for electrons but at dose rates three orders of magnitude greater. The results were attributed to the dependences of the radiation defect-forming reactions on the charge state of defects which was influenced by the formation of disordered regions in the case of proton irradiation

  6. Radiation flux measuring device

    International Nuclear Information System (INIS)

    Corte, E.; Maitra, P.

    1977-01-01

    A radiation flux measuring device is described which employs a differential pair of transistors, the output of which is maintained constant, connected to a radiation detector. Means connected to the differential pair produce a signal representing the log of the a-c component of the radiation detector, thereby providing a signal representing the true root mean square logarithmic output. 3 claims, 2 figures

  7. Conductivity of ion dielectrics during the mean flux-density electron- and X-ray pulse radiation

    International Nuclear Information System (INIS)

    Vajsburd, D.I.; Mesyats, G.A.; Naminov, V.L.; Tavanov, Eh.G.

    1982-01-01

    Conductivity of ion dielectrics under electron and X-ray pulse radiation is investigated. Investigations have been conducted in the range of average beam densities in which extinction of low-energy conductivity takes place. Thin plates of alkali-halogen crystals have been used as samples. Small-dimensional accelerator with controlled beam parameters: 1-20 ns, 0.1-2000 A/cm 2 , 0.3-0.5 MeV has been used for radiation. Temperature dependence of conductivity current pulse is determined. Time resolution of 10 - 10 s is achieved. In the 70-300 K range it practically coincides with radiation pulse. An essential inertial constituent is observed below 300 K. It is shown that at average beam densities a comparable contribution into fast conductivity is made by intracentre conductivity independent of temperature and high-temperature conductivity which decreases with temperature with activation energy equal to the energy of short-wave background. That is why amplitude of fast constituent decreases with temperature slower than high-energy conductivity

  8. Planck intermediate results - LII. Planet flux densities

    DEFF Research Database (Denmark)

    Akrami, Y.; Ashdown, M.; Aumont, J.

    2017-01-01

    Measurements of flux density are described for five planets, Mars, Jupiter, Saturn, Uranus, and Neptune, across the six Planck High Frequency Instrument frequency bands (100–857 GHz) and these are then compared with models and existing data. In our analysis, we have also included estimates...... of the brightness of Jupiter and Saturn at the three frequencies of the Planck Low Frequency Instrument (30, 44, and 70 GHz). The results provide constraints on the intrinsic brightness and the brightness time-variability of these planets. The majority of the planet flux density estimates are limited by systematic...... errors, but still yield better than 1% measurements in many cases. Applying data from Planck HFI, the Wilkinson Microwave Anisotropy Probe (WMAP), and the Atacama Cosmology Telescope (ACT) to a model that incorporates contributions from Saturn’s rings to the planet’s total flux density suggests a best...

  9. Compilation of neutron flux density spectra and reaction rates in different neutron fields. V.3

    International Nuclear Information System (INIS)

    Ertek, C.

    1980-04-01

    Upon the recommendation of the International Working Group of Reactor Radiation Measurements (IWGRRM) a compilation of documents containing neutron flux density spectra and the reaction rates obtained by activiation and fission foils in different neutron fields is presented

  10. Sensors for Metering Heat Flux Area Density and Metrological Equipment for the Heat Flux Density Measurement

    Science.gov (United States)

    Doronin, D. O.

    2018-04-01

    The demand in measuring and studies of heat conduction of various media is very urgent now. This article considers the problem of heat conduction monitoring and measurement in various media and materials in any industries and branches of science as well as metrological support of the heat flux measurement equipment. The main study objects are both the sensors manufactured and facilities onto which these sensors will be installed: different cladding structures of the buildings, awnings, rocket fairings, boiler units, internal combustion engines. The Company develops and manufactures different types of heat flux sensors: thermocouple, thin-film, heterogeneous gradient as well as metrological equipment for the gauging calibration of the heat flux density measurement. The calibration shall be performed using both referencing method in the unit and by fixed setting of the heat flux in the unit. To manufacture heterogeneous heat flux gradient sensors (HHFGS) the Company developed and designed a number of units: diffusion welding unit, HHFGS cutting unit. Rather good quality HHFGS prototypes were obtained. At this stage the factory tests on the equipment for the heat flux density measurement equipment are planned. A high-sensitivity heat flux sensor was produced, now it is tested at the Construction Physics Research Institute (Moscow). It became possible to create thin-film heat flux sensors with the sensitivity not worse than that of the sensors manufactured by Captec Company (France). The Company has sufficient premises to supply the market with a wide range of sensors, to master new sensor manufacture technologies which will enable their application range.

  11. Dynamic ignition regime of condensed system by radiate heat flux

    International Nuclear Information System (INIS)

    Arkhipov, V A; Zolotorev, N N; Korotkikh, A G; Kuznetsov, V T

    2017-01-01

    The main ignition characteristics of high-energy materials are the ignition time and critical heat flux allowing evaluation of the critical conditions for ignition, fire and explosive safety for the test solid propellants. The ignition process is typically studied in stationary conditions of heat input at constant temperature of the heating surface, environment or the radiate heat flux on the sample surface. In real conditions, ignition is usually effected at variable time-dependent values of the heat flux. In this case, the heated layer is formed on the sample surface in dynamic conditions and significantly depends on the heat flux change, i.e. increasing or decreasing falling heat flux in the reaction period of the propellant sample. This paper presents a method for measuring the ignition characteristics of a high-energy material sample in initiation of the dynamic radiant heat flux, which includes the measurement of the ignition time when exposed to a sample time varying radiant heat flux given intensity. In case of pyroxyline containing 1 wt. % of soot, it is shown that the ignition times are reduced by 20–50 % depending on the initial value of the radiant flux density in initiation by increasing or decreasing radiant heat flux compared with the stationary conditions of heat supply in the same ambient conditions. (paper)

  12. Calculation of flux density distribution on irradiation field of electron accelerator

    International Nuclear Information System (INIS)

    Tanaka, Ryuichi

    1977-03-01

    The simple equation of flux density distribution in the irradiation field of an ordinary electron accelerator is a function of the physical parameters concerning electron irradiation. Calculation is based on the mean square scattering angle derived from a simple multiple scattering theory, with the correction factors of air scattering, beam scanning and number transmission coefficient. The flux density distribution was measured by charge absorption in a graphite target set in the air. For the calculated mean square scattering angles of 0.089-0.29, the values of calculation agree with those by experiment within about 10% except at large scattering angles. The method is applicable to dose evaluation of ordinary electron accelerators and design of various irradiators for radiation chemical reaction. Applicability of the simple multiple scattering theory in calculation of the scattered flux density and periodical variation of the flux density of scanning beam are also described. (auth.)

  13. Device for measuring neutron-flux distribution density

    International Nuclear Information System (INIS)

    Rozenbljum, N.D.; Mitelman, M.G.; Kononovich, A.A.; Kirsanov, V.S.; Zagadkin, V.A.

    1977-01-01

    An arrangement is described for measuring the distribution of neutron flux density over the height of a nuclear reactor core and which may be used for monitoring energy release or for detecting deviations of neutron flux from an optimal level so that subsequent balance can be achieved. It avoids mutual interference of detectors. Full constructional details are given. (UK)

  14. AN ACCURATE FLUX DENSITY SCALE FROM 1 TO 50 GHz

    International Nuclear Information System (INIS)

    Perley, R. A.; Butler, B. J.

    2013-01-01

    We develop an absolute flux density scale for centimeter-wavelength astronomy by combining accurate flux density ratios determined by the Very Large Array between the planet Mars and a set of potential calibrators with the Rudy thermophysical emission model of Mars, adjusted to the absolute scale established by the Wilkinson Microwave Anisotropy Probe. The radio sources 3C123, 3C196, 3C286, and 3C295 are found to be varying at a level of less than ∼5% per century at all frequencies between 1 and 50 GHz, and hence are suitable as flux density standards. We present polynomial expressions for their spectral flux densities, valid from 1 to 50 GHz, with absolute accuracy estimated at 1%-3% depending on frequency. Of the four sources, 3C286 is the most compact and has the flattest spectral index, making it the most suitable object on which to establish the spectral flux density scale. The sources 3C48, 3C138, 3C147, NGC 7027, NGC 6542, and MWC 349 show significant variability on various timescales. Polynomial coefficients for the spectral flux density are developed for 3C48, 3C138, and 3C147 for each of the 17 observation dates, spanning 1983-2012. The planets Venus, Uranus, and Neptune are included in our observations, and we derive their brightness temperatures over the same frequency range.

  15. Compilation of neutron flux density spectra and reaction rates in different neutron fields

    International Nuclear Information System (INIS)

    Ertek, C.

    1979-07-01

    Upon the recommendation of International Working Group of Reactor Radiation Measurements (IWGRRM), the compilation of neutron flux density spectra and the reaction rates obtained by activation and fission foils in different neutron fields is presented. The neutron fields considered are as follows: 1/E; iron block; LWR core and pressure vessel; LMFBR core and blanket; CTR first wall and blanket; fission spectrum

  16. Dynamics of photosynthetic photon flux density (PPFD) and estimates in coastal northern California

    Science.gov (United States)

    The seasonal trends and diurnal patterns of Photosynthetically Active Radiation (PAR) were investigated in the San Francisco Bay Area of Northern California from March through August in 2007 and 2008. During these periods, the daily values of PAR flux density (PFD), energy loading with PAR (PARE), a...

  17. Flux Density through Guides with Microstructured Twisted Clad DB Medium

    Directory of Open Access Journals (Sweden)

    M. A. Baqir

    2014-01-01

    Full Text Available The paper deals with the study of flux density through a newly proposed twisted clad guide containing DB medium. The inner core and the outer clad sections are usual dielectrics, and the introduced twisted windings at the core-clad interface are treated under DB boundary conditions. The pitch angle of twist is supposed to greatly contribute towards the control over the dispersion characteristics of the guide. The eigenvalue equation for the guiding structure is deduced, and the analytical investigations are made to explore the propagation patterns of flux densities corresponding to the sustained low-order hybrid modes under the situation of varying pitch angles. The emphasis has been put on the effects due to the DB twisted pitch on the propagation of energy flux density through the guide.

  18. Surface radiation fluxes in transient climate simulations

    Science.gov (United States)

    Garratt, J. R.; O'Brien, D. M.; Dix, M. R.; Murphy, J. M.; Stephens, G. L.; Wild, M.

    1999-01-01

    Transient CO 2 experiments from five coupled climate models, in which the CO 2 concentration increases at rates of 0.6-1.1% per annum for periods of 75-200 years, are used to document the responses of surface radiation fluxes, and associated atmospheric properties, to the CO 2 increase. In all five models, the responses of global surface temperature and column water vapour are non-linear and fairly tightly constrained. Thus, global warming lies between 1.9 and 2.7 K at doubled, and between 3.1 and 4.1 K at tripled, CO 2, whilst column water vapour increases by between 3.5 and 4.5 mm at doubled, and between 7 and 8 mm at tripled, CO 2. Global cloud fraction tends to decrease by 1-2% out to tripled CO 2, mainly the result of decreases in low cloud. Global increases in column water, and differences in these increases between models, are mainly determined by the warming of the tropical oceans relative to the middle and high latitudes; these links are emphasised in the zonal profiles of warming and column water vapour increase, with strong water vapour maxima in the tropics. In all models the all-sky shortwave flux to the surface S↓ (global, annual average) changes by less than 5 W m -2 out to tripled CO 2, in some cases being essentially invariant in time. In contrast, the longwave flux to the surface L↓ increases significantly, by 25 W m -2 typically at tripled CO 2. The variations of S↓ and L↓ (clear-sky and all-sky fluxes) with increase in CO 2 concentration are generally non-linear, reflecting the effects of ocean thermal inertia, but as functions of global warming are close to linear in all five models. This is best illustrated for the clear-sky downwelling fluxes, and the net radiation. Regionally, as illustrated in zonal profiles and global distributions, greatest changes in both S↓ and L↓ are the result primarily of local maxima in warming and column water vapour increases.

  19. Coordinates for Representing Radiation Belt Particle Flux

    Science.gov (United States)

    Roederer, Juan G.; Lejosne, Solène

    2018-02-01

    Fifty years have passed since the parameter "L-star" was introduced in geomagnetically trapped particle dynamics. It is thus timely to review the use of adiabatic theory in present-day studies of the radiation belts, with the intention of helping to prevent common misinterpretations and the frequent confusion between concepts like "distance to the equatorial point of a field line," McIlwain's L-value, and the trapped particle's adiabatic L* parameter. And too often do we miss in the recent literature a proper discussion of the extent to which some observed time and space signatures of particle flux could simply be due to changes in magnetospheric field, especially insofar as off-equatorial particles are concerned. We present a brief review on the history of radiation belt parameterization, some "recipes" on how to compute adiabatic parameters, and we illustrate our points with a real event in which magnetospheric disturbance is shown to adiabatically affect the particle fluxes measured onboard the Van Allen Probes.

  20. Magnetic flux density in the heliosphere through several solar cycles

    Energy Technology Data Exchange (ETDEWEB)

    Erdős, G. [Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Balogh, A., E-mail: erdos.geza@wigner.mta.hu [The Blackett Laboratory, Imperial College London, London SW7 2BZ (United Kingdom)

    2014-01-20

    We studied the magnetic flux density carried by solar wind to various locations in the heliosphere, covering a heliospheric distance range of 0.3-5.4 AU and a heliolatitudinal range from 80° south to 80° north. Distributions of the radial component of the magnetic field, B{sub R} , were determined over long intervals from the Helios, ACE, STEREO, and Ulysses missions, as well as from using the 1 AU OMNI data set. We show that at larger distances from the Sun, the fluctuations of the magnetic field around the average Parker field line distort the distribution of B{sub R} to such an extent that the determination of the unsigned, open solar magnetic flux density from the average (|B{sub R} |) is no longer justified. We analyze in detail two methods for reducing the effect of fluctuations. The two methods are tested using magnetic field and plasma velocity measurements in the OMNI database and in the Ulysses observations, normalized to 1 AU. It is shown that without such corrections for the fluctuations, the magnetic flux density measured by Ulysses around the aphelion phase of the orbit is significantly overestimated. However, the matching between the in-ecliptic magnetic flux density at 1 AU (OMNI data) and the off-ecliptic, more distant, normalized flux density by Ulysses is remarkably good if corrections are made for the fluctuations using either method. The main finding of the analysis is that the magnetic flux density in the heliosphere is fairly uniform, with no significant variations having been observed either in heliocentric distance or heliographic latitude.

  1. Measurements relating fire radiative energy density and surface fuel consumption - RxCADRE 2011 and 2012

    Science.gov (United States)

    Andrew T. Hudak; Matthew B. Dickinson; Benjamin C. Bright; Robert L. Kremens; E. Louise Loudermilk; Joseph J. O' Brien; Benjamin S. Hornsby; Roger D. Ottmar

    2016-01-01

    Small-scale experiments have demonstrated that fire radiative energy is linearly related to fuel combusted but such a relationship has not been shown at the landscape level of prescribed fires. This paper presents field and remotely sensed measures of pre-fire fuel loads, consumption, fire radiative energy density (FRED) and fire radiative power flux density (FRFD),...

  2. 47 CFR 25.208 - Power flux density limits.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Power flux density limits. 25.208 Section 25.208 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE... emissions from all co-frequency space stations of a single non-geostationary-satellite orbit (NGSO) system...

  3. Surface radiant flux densities inferred from LAC and GAC AVHRR data

    Science.gov (United States)

    Berger, F.; Klaes, D.

    To infer surface radiant flux densities from current (NOAA-AVHRR, ERS-1/2 ATSR) and future meteorological (Envisat AATSR, MSG, METOP) satellite data, the complex, modular analysis scheme SESAT (Strahlungs- und Energieflüsse aus Satellitendaten) could be developed (Berger, 2001). This scheme allows the determination of cloud types, optical and microphysical cloud properties as well as surface and TOA radiant flux densities. After testing of SESAT in Central Europe and the Baltic Sea catchment (more than 400scenes U including a detailed validation with various surface measurements) it could be applied to a large number of NOAA-16 AVHRR overpasses covering the globe.For the analysis, two different spatial resolutions U local area coverage (LAC) andwere considered. Therefore, all inferred results, like global area coverage (GAC) U cloud cover, cloud properties and radiant properties, could be intercompared. Specific emphasis could be made to the surface radiant flux densities (all radiative balance compoments), where results for different regions, like Southern America, Southern Africa, Northern America, Europe, and Indonesia, will be presented. Applying SESAT, energy flux densities, like latent and sensible heat flux densities could also be determined additionally. A statistical analysis of all results including a detailed discussion for the two spatial resolutions will close this study.

  4. Maximum power flux of auroral kilometric radiation

    International Nuclear Information System (INIS)

    Benson, R.F.; Fainberg, J.

    1991-01-01

    The maximum auroral kilometric radiation (AKR) power flux observed by distant satellites has been increased by more than a factor of 10 from previously reported values. This increase has been achieved by a new data selection criterion and a new analysis of antenna spin modulated signals received by the radio astronomy instrument on ISEE 3. The method relies on selecting AKR events containing signals in the highest-frequency channel (1980, kHz), followed by a careful analysis that effectively increased the instrumental dynamic range by more than 20 dB by making use of the spacecraft antenna gain diagram during a spacecraft rotation. This analysis has allowed the separation of real signals from those created in the receiver by overloading. Many signals having the appearance of AKR harmonic signals were shown to be of spurious origin. During one event, however, real second harmonic AKR signals were detected even though the spacecraft was at a great distance (17 R E ) from Earth. During another event, when the spacecraft was at the orbital distance of the Moon and on the morning side of Earth, the power flux of fundamental AKR was greater than 3 x 10 -13 W m -2 Hz -1 at 360 kHz normalized to a radial distance r of 25 R E assuming the power falls off as r -2 . A comparison of these intense signal levels with the most intense source region values (obtained by ISIS 1 and Viking) suggests that multiple sources were observed by ISEE 3

  5. Polycrystalline semiconductor probes for monitoring the density distribution of an intense thermal neutron flux in nuclear reactors

    International Nuclear Information System (INIS)

    Graul, J.; Mueller, R.G.; Wagner, E.

    1975-05-01

    The applicability of semiconductor detectors for high thermal neutron flux densities is theoretically estimated and experimentally examined. For good thermal stability and low radiation capture rate silicon carbide is used as semiconductor material, produced in polycristalline layers to achieve high radiation resistance. The relations between crystallinity, photoelectric sensitivity and radiation resistance are shown. The radiation resistance of polycrystalline SiC-probes is approximately 100 times greater than that of conventional single crystal radiation detectors. For thermal neutron measurement they can be used in the flux range of approx. 10 10 13 (cm -2 sec -1 ) with operation times of 1.6 a >= tsub(b,max) >= 30 d, resp. (orig.) [de

  6. Explosive mechanism of metal destruction by intense electromagnetic radiation flux

    International Nuclear Information System (INIS)

    Martynyuk, M.M.

    1977-01-01

    The metal destruction by a powerful flux of electromagnetic radiation is considered on the basis of thermodynamics and kinetics of the transition of molten metal to vapour during its rapid heating. The possibility is discussed of obtaining a metastable liquid-metal phase and of its explosion transition to a stable two-phase state (phase explosion of metastable liquid). It has been shown that at densities of radiation beam ensuring the heating of the metal to the spinodal point Tsub(s) during a time tsub(s)=10 -5 -10 -7 s the vaporization of the matter from the surface of the liquid is negligible, and the main mechanism of the metal destruction is the phase explosion of the metastable liquid-metal phase which originates in the Tsub(s) vicinity. The experimental data on the electric explosion of conductors for tsub(s)=10 -6 -10 -5 s has served as a basis for calculating the excess enthalpy and the proportion of the vapour phase formed in the phase explosion of Cu, Ag, Au, Zn, Cd, Al, Pb, Zr, Nb, Mo, W, Pt and Re. The particularities of the phase explosion at flux densities corresponding to tsub(s)( -8 s are considered

  7. Transport critical current density in flux creep model

    International Nuclear Information System (INIS)

    Wang, J.; Taylor, K.N.R.; Russell, G.J.; Yue, Y.

    1992-01-01

    The magnetic flux creep model has been used to derive the temperature dependence of the critical current density in high temperature superconductors. The generally positive curvature of the J c -T diagram is predicted in terms of two interdependent dimensionless fitting parameters. In this paper, the results are compared with both SIS and SNS junction models of these granular materials, neither of which provides a satisfactory prediction of the experimental data. A hybrid model combining the flux creep and SNS mechanisms is shown to be able to account for the linear regions of the J c -T behavior which are observed in some materials

  8. Flux-limited diffusion models in radiation hydrodynamics

    International Nuclear Information System (INIS)

    Pomraning, G.C.; Szilard, R.H.

    1993-01-01

    The authors discuss certain flux-limited diffusion theories which approximately describe radiative transfer in the presence of steep spatial gradients. A new formulation is presented which generalizes a flux-limited description currently in widespread use for large radiation hydrodynamic calculations. This new formation allows more than one Case discrete mode to be described by a flux-limited diffusion equation. Such behavior is not extant in existing formulations. Numerical results predicted by these flux-limited diffusion models are presented for radiation penetration into an initially cold halfspace. 37 refs., 5 figs

  9. Effect of Thermospheric Neutral Density upon Inner Trapped-belt Proton Flux

    Science.gov (United States)

    Wilson, Thomas L.; Lodhi, M. A. K.; Diaz, Abel B.

    2007-01-01

    We wish to point out that a secular change in the Earth's atmospheric neutral density alters charged-particle lifetime in the inner trapped radiation belts, in addition to the changes recently reported as produced by greenhouse gases. Heretofore, changes in neutral density have been of interest primarily because of their effect on the orbital drag of satellites. We extend this to include the orbital lifetime of charged particles in the lower radiation belts. It is known that the charged-belt population is coupled to the neutral density of the atmosphere through changes induced by solar activity, an effect produced by multiple scattering off neutral and ionized atoms along with ionization loss in the thermosphere where charged and neutral populations interact. It will be shown here that trapped-belt flux J is bivariant in energy E and thermospheric neutral density , as J(E,rho). One can conclude that proton lifetimes in these belts are also directly affected by secular changes in the neutral species populating the Earth s thermosphere. This result is a consequence of an intrinsic property of charged-particle flux, that flux is not merely a function of E but is dependent upon density rho when a background of neutrals is present.

  10. High frequency characterization of Galfenol minor flux density loops

    Directory of Open Access Journals (Sweden)

    Ling Weng

    2017-05-01

    Full Text Available This paper presents the first measurement of ring-shaped Galfenol’s high frequency-dependent minor flux density loops. The frequencies of applied AC magnetic field are 1k, 5k, 10k, 50k, 100k, 200k, 300k, 500 kHz. The measurements show that the cycle area between the flux density and magnetic field curves increase with increasing frequency. High frequency-dependent characterization, including coercivity, specific power loss, residual induction, and maximum relative permeability are discussed. Minor loops for different max induction are also measured and discussed at the same frequency 100 kHz. Minor loops with the same max induction 0.05 T for different frequencies 50, 100, 200, 300, 400 kHz are measured and specific power loss are discussed.

  11. A High Torque Density Axial Flux SRM with Modular Stator

    Directory of Open Access Journals (Sweden)

    Y Ebrahimi

    2015-12-01

    Full Text Available A novel structure of switched reluctance motors (SRMs is proposed. The proposed structure uses the benefits of the axial flux path, short flux path, segmental rotor, and flux reversal free stator motors all together to improve the torque density of the SRMs. The main geometrical, electrical and physical specifications are presented. In addition, some features of the proposed structure are compared with those of a state-of-the-art radial flux SRM, considered as a reference motor. Then, the proposed structure is modified by employing a higher number of rotor segments than the stator modules and at the same time, reshaped stator modules tips. Achieved results reveal that, compared with the reference motor, the proposed and the modified proposed motors deliver about the same torque with 36.5% and 46.7% lower active material mass, respectively. The efficiency and torque production capability for the extended current densities are also retained. These make the proposed structures a potentially proper candidate for the electric vehicles (EVs and hybrid electric vehicles (HEVs as an in-wheel motor.

  12. Radon flux maps for the Netherlands and Europe using terrestrial gamma radiation derived from soil radionuclides

    Science.gov (United States)

    Manohar, S. N.; Meijer, H. A. J.; Herber, M. A.

    2013-12-01

    Naturally occurring radioactive noble gas, radon (222Rn) is a valuable tracer to study atmospheric processes and to validate global chemical transport models. However, the use of radon as a proxy in atmospheric and climate research is limited by the uncertainties in the magnitude and distribution of the radon flux density over the Earth's surface. Terrestrial gamma radiation is a useful proxy for generating radon flux maps. A previously reported radon flux map of Europe used terrestrial gamma radiation extracted from automated radiation monitoring networks. This approach failed to account for the influence of local artificial radiation sources around the detector, leading to under/over estimation of the reported radon flux values at different locations. We present an alternative approach based on soil radionuclides which enables us to generate accurate radon flux maps with good confidence. Firstly, we present a detailed comparison between the terrestrial gamma radiation obtained from the National Radiation Monitoring network of the Netherlands and the terrestrial gamma radiation calculated from soil radionuclides. Extending further, we generated radon flux maps of the Netherlands and Europe using our proposed approach. The modelled flux values for the Netherlands agree reasonably well with the two observed direct radon flux measurements (within 2σ level). On the European scale, we find that the observed radon flux values are higher than our modelled values and we introduce a correction factor to account for this difference. Our approach discussed in this paper enables us to develop reliable and accurate radon flux maps in countries with little or no information on radon flux values.

  13. Internal wave energy flux from density perturbations in nonlinear stratifications

    Science.gov (United States)

    Lee, Frank M.; Allshouse, Michael R.; Swinney, Harry L.; Morrison, P. J.

    2017-11-01

    Tidal flow over the topography at the bottom of the ocean, whose density varies with depth, generates internal gravity waves that have a significant impact on the energy budget of the ocean. Thus, understanding the energy flux (J = p v) is important, but it is difficult to measure simultaneously the pressure and velocity perturbation fields, p and v . In a previous work, a Green's-function-based method was developed to calculate the instantaneous p, v , and thus J , given a density perturbation field for a constant buoyancy frequency N. Here we extend the previous analytic Green's function work to include nonuniform N profiles, namely the tanh-shaped and linear cases, because background density stratifications that occur in the ocean and some experiments are nonlinear. In addition, we present a finite-difference method for the general case where N has an arbitrary profile. Each method is validated against numerical simulations. The methods we present can be applied to measured density perturbation data by using our MATLAB graphical user interface EnergyFlux. PJM was supported by the U.S. Department of Energy Contract DE-FG05-80ET-53088. HLS and MRA were supported by ONR Grant No. N000141110701.

  14. Evaluation of neutron flux density and power density with SPN-detectors and micro calorimeters

    International Nuclear Information System (INIS)

    Gehre, G.; Rindelhardt, U.; Seidenkranz, T.; Hogel, J.; Jirousek, V.; Vazek, J.

    1983-02-01

    During investigations with a special equipped fuel assembly in the Rheinsberg nuclear power station the neutron flux and the power density were evaluated from measurements with SPN-detectors and micro calorimeters. The reliability of both detector types, their measurement accuracy under different physical conditions and the usefulness of the developed calculation models are discussed in detail. The thermal flux and the power density evaluated with SPND's agree well with theoretical results. The values obtained through micro calorimeter measurements are systematic lower by about 18%. This deviation is probably a result of differences in the used calculation models. (author)

  15. Flux density calibration in diffuse optical tomographic systems.

    Science.gov (United States)

    Biswas, Samir Kumar; Rajan, Kanhirodan; Vasu, Ram M

    2013-02-01

    The solution of the forward equation that models the transport of light through a highly scattering tissue material in diffuse optical tomography (DOT) using the finite element method gives flux density (Φ) at the nodal points of the mesh. The experimentally measured flux (Umeasured) on the boundary over a finite surface area in a DOT system has to be corrected to account for the system transfer functions (R) of various building blocks of the measurement system. We present two methods to compensate for the perturbations caused by R and estimate true flux density (Φ) from Umeasuredcal. In the first approach, the measurement data with a homogeneous phantom (Umeasuredhomo) is used to calibrate the measurement system. The second scheme estimates the homogeneous phantom measurement using only the measurement from a heterogeneous phantom, thereby eliminating the necessity of a homogeneous phantom. This is done by statistically averaging the data (Umeasuredhetero) and redistributing it to the corresponding detector positions. The experiments carried out on tissue mimicking phantom with single and multiple inhomogeneities, human hand, and a pork tissue phantom demonstrate the robustness of the approach.

  16. Manifestation of solar activity in solar wind particle flux density

    International Nuclear Information System (INIS)

    Kovalenko, V.A.

    1988-01-01

    An analysis has been made of the origin of long-term variations in flux density of solar wind particles (nv) for different velocity regimes. The study revealed a relationship of these variations to the area of the polar coronal holes (CH). It is shown that within the framework of the model under development, the main longterm variations of nv are a result of the latitude redistribution of the solar wind mass flux in the heliosphere and are due to changes in the large-scale geometry of the solar plasma flow in the corona. A study has been made of the variations of nv for high speed solar wind streams. It is found that nv in high speed streams which are formed in CH, decreases from minimum to maximum solar activity. The analysis indicates that this decrease is attributable to the magnetic field strength increase in coronal holes. It has been found that periods of rapid global changes of background magnetic fields on the Sun are accompanied by a reconfiguration of coronal magnetic fields, rapid changes in the length of quiescent filaments, and by an increase in the density of the particle flux of a high speed solar wind. It has been established that these periods precede the formation of CH, corresponding to the increase in solar wind velocity near the Earth and to enhancement of the level of geomagnetic disturbance. (author)

  17. High Torque Density Transverse Flux Machine without the Need to Use SMC Material for 3D Flux Paths

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Wu, Weimin

    2015-01-01

    This paper presents a new transverse flux permanent magnet machine. In a normal transverse flux machine, complicated 3-D flux paths often exist. Such 3-D flux paths would require the use of soft magnetic composites material instead of laminations for construction of the machine stator. In the new...... machine topology proposed in this paper, by advantageously utilizing the magnetic flux path provided by an additional rotor, use of laminations that allow 2-D flux paths only will be sufficient to accomplish the required 3-D flux paths. The machine also has a high torque density and is therefore...

  18. Understanding the Effect of Atmospheric Density on the Cosmic Ray Flux Variations at the Earth Surface

    OpenAIRE

    Dayananda, Mathes; Zhang, Xiaohang; Butler, Carola; He, Xiaochun

    2013-01-01

    We report in this letter for the first time the numerical simulations of muon and neutron flux variations at the surface of the earth with varying air densities in the troposphere and stratosphere. The simulated neutron and muon flux variations are in very good agreement with the measured neutron flux variation in Oulu and the muon flux variation in Atlanta. We conclude from this study that the stratosphere air density variation dominates the effects on the muon flux changes while the density...

  19. Calculation of gamma-ray flux density above the Venus and Earth surfaces

    International Nuclear Information System (INIS)

    Surkov, Yu.A.; Manvelyan, O.S.

    1987-01-01

    Calculational results of dependence of flux density of nonscattered gamma-quanta on the height above the Venus and Earth planet surfaces are presented in the paper. Areas, where a certain part of gamma quanta is accumulated, are calaculted for each height. Spectra of scattered gamma quanta and their integral fluxes at different heights above the Venera planet surface are calculated. Effect of the atmosphere on gamma radiation recorded is considered. The results obtained allow to estimate optimal conditions for measuring gamma-fields above the Venus and Earth planet surfaces, to determine the area of the planet surface investigated. They are also necessary to determine the elementary composition of the rock according to the characteristic gamma radiation spectrum recorded

  20. On radiative density limits in stellarators

    International Nuclear Information System (INIS)

    Wobig, H.

    2001-01-01

    Density limits in stellarators are caused mainly by enhanced impurity radiation leading to a collapse of the temperature. A simple model can be established, which computes the temperature in the plasma with a fixed heating profile and a temperature-dependent radiation profile. If the temperature-dependent radiation function has one or several extrema, multiple solutions of the transport equation exist and radiative collapse occurs when the high temperature branch merges with the unstable temperature branch. At this bifurcation point the temperature decreases to a stable low temperature solution. The bifurcation point is a function of the heating power and the plasma density. Thus a density limit can be defined as the point where bifurcation occurs. It is shown that bifurcation and sudden temperature collapse does not occur below a power threshold. Anomalous thermal conductivity and the details of the impurity radiation, which in the present model is assumed to be in corona equilibrium, determine the scaling of the density limit. A model of the anomalous transport is developed, which leads to Gyro-Bohm scaling of the confinement time. The density limit based on this transport model is close to experimental findings in Wendelstein 7-AS. (author)

  1. Injection space charge: enlargements of flux density functioning point choice

    International Nuclear Information System (INIS)

    Ropert, A.

    In Saturne, injection consists of a synchrobetatron filling of the chamber, with the goal of providing a beam with the following characteristics circulating in the machine: horizontal flux density 90 πmm mrd, vertical flux density 210 πmm mrd, dispersion in moments +- 7 x 10 -3 , and number of particles 2 x 10 12 . The determination of the principal injection parameters was made by means of GOC calculation programs. The goal of this study is to show a certain number of phenomena induced by the forces due to space charge and left suspended up to this point: variations in the intensity injectable into the machine extension of the beam occupation zone in the ν/sub x'/ ν/sub z/ diagram, and turn-turn interactions. The effects of the space charge lead to a deterioration of the injected beam for certain functioning points leading to the selection of a zone in the ν/sub x'/ ν/sub z/ diagram that is particularly suitable for beam injection

  2. Radiation damage in molybdenum and tungsten in high neutron fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Veljkovic, S; Milasin, N [Institute of Nuclear Sciences Boris Kidric, Department of Reactor Materials, Vinca, Beograd (Serbia and Montenegro)

    1964-04-15

    The effects of radiation on molybdenum and tungsten in high neutron fluxes are presented. The changes induced, particularly defects with a high migration activation energy, are analyzed. The correlation of these changes with the basic concepts of radiation damage in solids is considered. An attempt is made to relate the defects studied with the changes in macroscopic properties (author)

  3. Radiation damage in molybdenum and tungsten in high neutron fluxes

    International Nuclear Information System (INIS)

    Veljkovic, S.; Milasin, N.

    1964-01-01

    The effects of radiation on molybdenum and tungsten in high neutron fluxes are presented. The changes induced, particularly defects with a high migration activation energy, are analyzed. The correlation of these changes with the basic concepts of radiation damage in solids is considered. An attempt is made to relate the defects studied with the changes in macroscopic properties (author)

  4. International intercomparison on the neutron flux density spectrum just before the REAL-80 project

    International Nuclear Information System (INIS)

    Ertek, C.

    1981-06-01

    This work briefly presents the results of the international intercomparison on the neutron flux density spectrum just before the REAL-80 intercomparison project. Some of the results of this intercomparison with a smaller number of laboratories will be also reflected in the REAL-80 project, therefore, it has some significant issues. This work is performed within the IAEA programme on standardization of reactor radiation measurements, one of the important objectives of which is the assistance of laboratories in Member States to implement or intercompare the multiple foil activation techniques for different neutron field measurements

  5. Calculation of the flux density of gamma rays above the surface of Venus and the Earth

    International Nuclear Information System (INIS)

    Surkov, Yu.A.; Manvelyan, O.S.

    1987-01-01

    In this article the authors present the results of calculating the flux density of unscattered gamma rays as a function of height above the surfaces of Venus and the Earth. At each height they calculate the areas which will collect a certain fraction of the gamma rays. The authors calculate the spectra of scattered gamma rays, as well as their integrated fluxes at various heights above the surface of Venus. They consider how the atmosphere will affect the recording of gamma rays. Their results enable them to evaluate the optimal conditions for measuring the gamma-ray fields above the surfaces of Venus and the Earth and to determine the area of the planet which can be investigated in this way. These results are also necessary if they are to determine the elemental composition of the rock from the characteristic recorded spectrum of gamma radiation

  6. Profiles of radiation power density in WEGA stellarator

    International Nuclear Information System (INIS)

    Zhang, D.; Otte, M.; Giannone, L.

    2005-01-01

    On the WEGA stellarator, a 12 channel bolometer camera has been used to measure the radiation power losses of the plasma, which is heated by ECR at 2.45 GHz with a maximum power of 26 kW. The typical electron temperatures achieved are around 10 eV. The bolometer is of the Au resistor type and is positioned on the mid-plane, viewing the plasma from the low-field side with a spatial resolution of about 6 cm. The viewing angle is opened to poloidally (±47 o ) and covers the whole cross-section. Angular profiles of radiation power density (emissivity) can be achieved using the measured fluxes to the channels, which are given by the integrals along the sight lines. Using Abel inversion with maximum entropy regularisation, radial profiles of emissivity could be obtained. It is found that the angular profile of emissivity depends on the magnetic configuration, the working gas (Ar, He) and the heating scenario. Peaked and hollow emissivity profiles have been obtained by using different types of heating antenna. By changing the magnetic configuration, strong edge radiation has been observed. The largest emissivity values are obtained in the upper SOL range of Ar-discharges. This edge radiation can be reduced by shifting the flux surfaces inwards or by changing their shape at the antenna. The reconstruction of the radial profile of the emissivity was carried out in the case of a peaked angular profile with minimum edge radiation. The total radiation power was estimated by linear extrapolation of the integrated radiation power in the viewing region to the torus volume. It is typically less than 30% of the ECRH input power, but depending on the ECRH input power, again the magnetic configuration, the working gas as well as the absolute field strength on the magnetic axis. Maximum radiation losses have been obtained around 0.6·B0, where B 0 =87.5 mT is the resonant field strength of the ECRH. No evidence for impurities was obtained from spectroscopic measurements, and thus the

  7. Mathematical model and simulations of radiation fluxes from buried radionuclides

    International Nuclear Information System (INIS)

    Ahmad Saat

    1999-01-01

    A mathematical model and a simple Monte Carlo simulations were developed to predict radiation fluxes from buried radionuclides. The model and simulations were applied to measured (experimental) data. The results of the mathematical model showed good acceptable order of magnitude agreement. A good agreement was also obtained between the simple simulations and the experimental results. Thus, knowing the radionuclide distribution profiles in soil from a core sample, it can be applied to the model or simulations to estimate the radiation fluxes emerging from the soil surface. (author)

  8. Flux Loop Measurements of the Magnetic Flux Density in the CMS Magnet Yoke

    CERN Document Server

    Klyukhin, V I; Ball, A.; Curé, B.; Gaddi, A.; Gerwig, H.; Mulders, M.; Hervé, A.; Loveless, R.

    2016-01-01

    The Compact Muon Solenoid (CMS) is a general purpose detector, designed to run at the highest luminosity at the CERN Large Hadron Collider (LHC). Its distinctive features include a 4 T superconducting solenoid with 6-m-diameter by 12.5-m-length free bore, enclosed inside a 10,000-ton return yoke made of construction steel. The return yoke consists of five dodecagonal three-layered barrel wheels and four end-cap disks at each end comprised of steel blocks up to 620 mm thick, which serve as the absorber plates of the muon detection system. To measure the field in and around the steel, a system of 22 flux loops and 82 3-D Hall sensors is installed on the return yoke blocks. A TOSCA 3-D model of the CMS magnet is developed to describe the magnetic field everywhere outside the tracking volume measured with the field-mapping machine. The first attempt is made to measure the magnetic flux density in the steel blocks of the CMS magnet yoke using the standard magnet discharge with the current ramp down speed of 1.5 A/...

  9. Flux canceling in three-dimensional radiative magnetohydrodynamic simulations

    Science.gov (United States)

    Thaler, Irina; Spruit, H. C.

    2017-05-01

    We aim to study the processes involved in the disappearance of magnetic flux between regions of opposite polarity on the solar surface using realistic three-dimensional (3D) magnetohydrodynamic (MHD) simulations. "Retraction" below the surface driven by magnetic forces is found to be a very effective mechanism of flux canceling of opposite polarities. The speed at which flux disappears increases strongly with initial mean flux density. In agreement with existing inferences from observations we suggest that this is a key process of flux disappearance within active complexes. Intrinsic kG strength concentrations connect the surface to deeper layers by magnetic forces, and therefore the influence of deeper layers on the flux canceling process is studied. We do this by comparing simulations extending to different depths. For average flux densities of 50 G, and on length scales on the order of 3 Mm in the horizontal and 10 Mm in depth, deeper layers appear to have only a mild influence on the effective rate of diffusion.

  10. A new empirical model to estimate hourly diffuse photosynthetic photon flux density

    Science.gov (United States)

    Foyo-Moreno, I.; Alados, I.; Alados-Arboledas, L.

    2018-05-01

    Knowledge of the photosynthetic photon flux density (Qp) is critical in different applications dealing with climate change, plant physiology, biomass production, and natural illumination in greenhouses. This is particularly true regarding its diffuse component (Qpd), which can enhance canopy light-use efficiency and thereby boost carbon uptake. Therefore, diffuse photosynthetic photon flux density is a key driving factor of ecosystem-productivity models. In this work, we propose a model to estimate this component, using a previous model to calculate Qp and furthermore divide it into its components. We have used measurements in urban Granada (southern Spain), of global solar radiation (Rs) to study relationships between the ratio Qpd/Rs with different parameters accounting for solar position, water-vapour absorption and sky conditions. The model performance has been validated with experimental measurements from sites having varied climatic conditions. The model provides acceptable results, with the mean bias error and root mean square error varying between - 0.3 and - 8.8% and between 9.6 and 20.4%, respectively. Direct measurements of this flux are very scarce so that modelling simulations are needed, this is particularly true regarding its diffuse component. We propose a new parameterization to estimate this component using only measured data of solar global irradiance, which facilitates its use for the construction of long-term data series of PAR in regions where continuous measurements of PAR are not yet performed.

  11. Proton flux under radiation belts: near-equatorial zone

    International Nuclear Information System (INIS)

    Grigoryan, O.R.; Panasyuk, M.I.; Petrov, A.N.; Kudela, K.

    2005-01-01

    In this work the features of low-energy proton flux increases in near-equatorial region (McIlvein parameter L th the proton flux (with energy from tens keV up to several MeV) increases are registering regularly. However modern proton flux models (for example AP8 model) works at L>1.15 only and does not take into account near-equatorial protons. These fluxes are not too big, but the investigation of this phenomenon is important in scope of atmosphere-ionosphere connections and mechanisms of particles transport in magnetosphere. In according to double charge-exchange model the proton flux in near-equatorial region does not depend on geomagnetic local time (MLT) and longitude. However the Azur satellite data and Kosmos-484, MIR station and Active satellite data revealed the proton flux dependence on longitude. The other feature of near-equatorial proton flux is the dependence on geomagnetic local time revealed in the Sampex satellite experiment and other experiments listed above. In this work the dependences on MLT and longitude are investigated using the Active satellite (30-500 keV) and Sampex satellite (>800 keV). This data confirms that main sources of near-equatorial protons are radiation belts and ring current. The other result is that near-equatorial protons are quasi-trapped. The empirical proton flux dependences on L, B at near-equatorial longitudes are presented. (author)

  12. Effect of Photosynthetic Photon Flux Density on Carboxylation Efficiency 1

    Science.gov (United States)

    Weber, James A.; Tenhunen, John D.; Gates, David M.; Lange, Otto L.

    1987-01-01

    The effect of photosynthetic photon flux density (PPFD) on photosynthetic response (A) to CO2 partial pressures between 35 pascals and CO2 compensation point (Γ) was investigated, especially below PPFD saturation. Spinacia oleracea cv `Atlanta,' Glycine max cv `Clark,' and Arbutus unedo were studied in detail. The initial slope of the photosynthetic response to CO2 (∂A/∂C[Γ]) was constant above a PPFD of about 500 to 600 micromoles per square meter per second for all three species; but declined rapidly with PPFD below this critical level. For Γ there was also a critical PPFD (approximately 200 micromoles per square meter per second for S. oleracea and G. max; 100 for A. unedo) above which Γ was essentially constant, but below which Γ increased with decreasing PPFD. All three species showed a dependence of ∂A/∂C(Γ) on PPFD at low PPFD. Simulated photosynthetic responses obtained with a biochemically based model of whole-leaf photosynthesis were similar to measured responses. PMID:16665640

  13. SINUPERM N: a new digital neutron flux density monitoring system

    International Nuclear Information System (INIS)

    Flick, H.A.

    1993-01-01

    The new SINUPERM N System is developed for Neutron Monitoring in nuclear power plants. The development was started in 1989 (with the design specification) and will be finished in 1993 (with the qualification). The first built will be the nuclear power plant in Borselle (Netherlands). The design is based on a microprocessor system with a digital signal processor for calculations and signal filtering. The separation between analogue-input signals and digital processing enables for each detector type special input modules and standard output interfaces e.g. field - bus. The wide range of the Neutron Flux Density from 10 -2 cm -2 s -1 up to 10 8 cm -2 s -1 for the out-of-pile instrumentation and up to 10 14 cm -2 s -1 for the in-core-instrumentation will be covered by the SINUPERM N system. The requirements to be met by the SINUPERM N system are the IEEE 323, IEC 987 and the German standard KTA-3503 for safety systems. Other standards for instrumentation and control systems like IEC 801, IEC 1131 and IEC 68 for EMV, climatic and seismic requirements are also included in the hardware type test. The software requirement depends on the IEC 880 standard. (author). 3 figs

  14. Radiative flux calculations at UV and visible wavelengths

    International Nuclear Information System (INIS)

    Grossman, A.S.; Grant, K.E.; Wuebbles, D.J.

    1993-10-01

    A radiative transfer model to calculate the short wavelength fluxes at altitudes between 0 and 80 km has been developed at LLNL. The wavelength range extends from 175--735 nm. This spectral range covers the UV-B wavelength region, 250--350 nm, with sufficient resolution to allow comparison of UV-B measurements with theoretical predictions. Validation studies for the model have been made for both UV-B ground radiation calculations and tropospheric solar radiative forcing calculations for various ozone distributions. These studies indicate that the model produces results which agree well with respect to existing UV calculations from other published models

  15. Investigating the impact of uneven magnetic flux density distribution on core loss estimation

    DEFF Research Database (Denmark)

    Niroumand, Farideh Javidi; Nymand, Morten; Wang, Yiren

    2017-01-01

    is calculated according to an effective flux density value and the macroscopic dimensions of the cores. However, the flux distribution in the core can alter by core shapes and/or operating conditions due to nonlinear material properties. This paper studies the element-wise estimation of the loss in magnetic......There are several approaches for loss estimation in magnetic cores, and all these approaches highly rely on accurate information about flux density distribution in the cores. It is often assumed that the magnetic flux density evenly distributes throughout the core and the overall core loss...

  16. SPACETRAN, Radiation Leakage from Cylinder with ANISN Flux Calculation

    International Nuclear Information System (INIS)

    Cramer, S.N.; Solomito, M.

    1974-01-01

    1 - Nature of physical problem solved: SPACETRAN is designed to calculate the energy-dependent total flux or some proportional quantity such as kerma, due to the radiation leakage from the surface of a right-circular cylinder at detector positions located at arbitrary distances from the surface. The assumptions are made that the radiation emerging from the finite cylinder has no spatial dependence and that a vacuum surrounds the cylinder. 2 - Method of solution: There are three versions of the program in the code package. SPACETRAN-I uses the surface angular fluxes calculated by the discrete ordinates SN code ANISN, as input. SPACETRAN-II assumes that the surface angular flux for all energies can be represented as a function (Cos(PHI))**N, where PHI is the angle between surface outward normal and radiation direction, and N is an integer specified by the user. For both versions the energy group structure and the number and location of detectors is arbitrary. The flux (or response function) for a given energy group at some detection point is computed by summing the contributions from each surface area element over the entire surface. The surface area elements are defined by input data. SPACETRAN-III uses surface angular fluxes from DOT-3. SPACETRAN-I handles contributions either from a cylinder 'end' or 'side', so the total contributions must be obtained by adding the results of separate end and side runs. ANISN angular fluxes are specified for discrete directions. In general, the direction between the detector and contributing area will not exactly coincide with one of these discrete directions. In this case, the ANISN angular flux for the 'closest' discrete direction is used to approximate the contribution to the detector. SPACETRAN-II handles contributions from both the side and end of a cylinder in a single run. Since the assumed angular distribution is specified by a continuous function, it is not necessary to perform the angle selection described above. For

  17. Evaluation of radiative fluxes over the north Indian Ocean

    Science.gov (United States)

    Ramesh Kumar, M. R.; Pinker, Rachel T.; Mathew, Simi; Venkatesan, R.; Chen, W.

    2018-05-01

    Radiative fluxes are a key component of the surface heat budget of the oceans. Yet, observations over oceanic region are sparse due to the complexity of radiation measurements; moreover, certain oceanic regions are substantially under-sampled, such as the north Indian Ocean. The National Institute of Ocean Technology, Chennai, India, under its Ocean Observation Program has deployed an Ocean Moored Network for the Northern Indian Ocean (OMNI) both in the Arabian Sea and the Bay of Bengal. These buoys are equipped with sensors to measure radiation and rainfall, in addition to other basic meteorological parameters. They are also equipped with sensors to measure sub-surface currents, temperature, and conductivity from the surface up to a depth of 500 m. Observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the National Aeronautics and Space Administration (NASA) AQUA and TERRA satellites have been used to infer surface radiation over the north Indian Ocean. In this study, we focus only on the shortwave (SW↓) fluxes. The evaluations of the MODIS-based SW↓ fluxes against the RAMA observing network have shown a very good agreement between them, and therefore, we use the MODIS-derived fluxes as a reference for the evaluation of the OMNI observations. In an early deployment of the OMNI buoys, the radiation sensors were placed at 2 m above the sea surface; subsequently, the height of the sensors was raised to 3 m. In this study, we show that there was a substantial improvement in the agreement between the buoy observations and the satellite estimates, once the sensors were raised to higher levels. The correlation coefficient increased from 0.87 to 0.93, and both the bias and standard deviations decreased substantially.

  18. Density perturbations in a braneworld universe with dark radiation

    International Nuclear Information System (INIS)

    Gumjudpai, Burin; Maartens, Roy; Gordon, Christopher

    2003-01-01

    We investigate the effects on cosmological density perturbations of dark radiation in a Randall-Sundrum 2-type braneworld. Dark radiation in the background is limited by observational constraints to be a small fraction of the radiation energy density, but it has an interesting qualitative effect in the radiation era. On large scales, it serves to slightly suppress the radiation density perturbations at late times, while boosting the perturbations in dark radiation. In a kinetic (stiff) era, the suppression is much stronger, and drives the density perturbations to zero

  19. New upper limits on the local metagalactic ionizing radiation density

    Science.gov (United States)

    Vogel, Stuart N.; Weymann, Ray; Rauch, Michael; Hamilton, Tom

    1995-01-01

    We have obtained H-alpha observations with the Maryland-Caltech Fabry-Perot Spectrometer attached to the Cassegrain focus of the 1.5 m telescope at Palomer Observatory in order to set limits on the number of ionizing photons from the local metagalactic radiation field. We have observed the SW component of the Haynes-Giovanelli cloud H I 1225+01, an intergalactic cloud which should be optimum for measuring the metagalactic flux because it is nearly opaque to ionizing photons, it does not appear to be significantly shielded from the metagalactic radiation field, and the limits on embedded or nearby ionizing sources are unusually low. For the area of the cloud with an H I column density greater than 10(exp 19)/sq cm we set a 2 sigma limit of 1.1 x 10(exp -19) ergs/sq cm/s/sq arcsec (20 mR) for the surface brightness of diffuse H-alpha. This implies a 2 sigma upper limit on the incident one-sided ionizing flux of Phi(sub ex) is less than 3 x 10(exp 4)/sq cm/s. For a radiation field of the form J(sub nu) is approximately nu(exp -1.4), this yields a firm 2 sigma upper limit on the local metagalactic photoionization rate of Gamma is less than 2 x 10(exp -13)/s, and an upper limit for the radiation field J(sub nu) at the Lyman limit of J(sub nu0) is less than 8 x 10(exp -23) ergs/sq cm/Hz/sr. We discuss previous efforts to constrain the metagalactic ionizing flux using H-alpha surface brightness observations and also other methods, and conclude that our result places the firmest upper limit on this flux. We also observed the 7 min diameter region centered on 3C 273 in which H-alpha emission at a velocity of approximately 1700 km/s was initially reported by Williams and Schommer. In agreement with T. B. Williams (private communication) we find the initial detection was spurious. We obtain a 2 sigma upper limit of 1.8 x 10(exp -19) ergs/sq cm/s/sq arcsec (32 mR) for the mean surface brightness of diffuse H-alpha, about a factor of 6 below the published value.

  20. The Global Character of the Flux of Downward Longwave Radiation

    Science.gov (United States)

    Stephens, Graeme L.; Wild, Martin; Stackhouse, Paul W., Jr.; L'Ecuyer, Tristan; Kato, Seiji; Henderson, David S.

    2012-01-01

    Four different types of estimates of the surface downwelling longwave radiative flux (DLR) are reviewed. One group of estimates synthesizes global cloud, aerosol, and other information in a radiation model that is used to calculate fluxes. Because these synthesis fluxes have been assessed against observations, the global-mean values of these fluxes are deemed to be the most credible of the four different categories reviewed. The global, annual mean DLR lies between approximately 344 and 350 W/sq m with an error of approximately +/-10 W/sq m that arises mostly from the uncertainty in atmospheric state that governs the estimation of the clear-sky emission. The authors conclude that the DLR derived from global climate models are biased low by approximately 10 W/sq m and even larger differences are found with respect to reanalysis climate data. The DLR inferred from a surface energy balance closure is also substantially smaller that the range found from synthesis products suggesting that current depictions of surface energy balance also require revision. The effect of clouds on the DLR, largely facilitated by the new cloud base information from the CloudSat radar, is estimated to lie in the range from 24 to 34 W/sq m for the global cloud radiative effect (all-sky minus clear-sky DLR). This effect is strongly modulated by the underlying water vapor that gives rise to a maximum sensitivity of the DLR to cloud occurring in the colder drier regions of the planet. The bottom of atmosphere (BOA) cloud effect directly contrast the effect of clouds on the top of atmosphere (TOA) fluxes that is maximum in regions of deepest and coldest clouds in the moist tropics.

  1. Losses in magnetic flux compression generators: Part 2, Radiation losses

    International Nuclear Information System (INIS)

    Fowler, C.M.

    1988-06-01

    This is the second monograph devoted to the analysis of flux losses in explosive driven magnetic flux compression generators. In the first monograph, flux losses from magnetic field penetration into conductor walls was studied by conventional diffusion theory. In the present report flux loss by radiation from the outer conductor walls is treated. Flux leakage rates through walls of finite thickness are first obtained by diffusion theory. It is shown, for normal wall thicknesses, that flux leakage is determined essentially by the wall conductance, defined as the product of wall thickness and wall conductivity. This remains true when the wall thickness is reduced to zero at unchanged conductance. In this case the wall is said to be coalesced. Solutions for a cavity bounded by a perfect conductor on one side and a coalesced wall on the other are then obtained using the complete Maxwell wave equations in both the cavity and free space beyond the coalesced wall. Several anomalies, noted earlier, that arise from diffusion analysis are resolved by the wave treatment. Conditions for the validity of the diffusion treatment are noted, and an expression is obtained within the framework of diffusion theory for energy radiated into space from the cavity walls. The free space wave equations are solved by using the method of characteristics in both the cavity and free space regions. An extension of the characteristic method to situations where the constitutive relations are non-linear is outlined in an appendix. For a special class of these relations, Riemann-like invariants are determined explicitly and used to solve a particular example

  2. Single-flux-quantum circuit technology for superconducting radiation detectors

    International Nuclear Information System (INIS)

    Fujimaki, Akira; Onogi, Masashi; Matsumoto, Tomohiro; Tanaka, Masamitsu; Sekiya, Akito; Hayakawa, Hisao; Yorozu, Shinichi; Terai, Hirotaka; Yoshikawa, Nobuyuki

    2003-01-01

    We discuss the application of the single-flux-quantum (SFQ) logic circuits to multi superconducting radiation detectors system. The SFQ-based analog-to-digital converters (ADCs) have the advantage in current sensitivity, which can reach less than 10 nA in a well-tuned ADC. We have also developed the design technology of the SFQ circuits. We demonstrate high-speed operation of large-scale integrated circuits such as a 2x2 cross/bar switch, arithmetic logic unit, indicating that our present SFQ technology is applicable to the multi radiation detectors system. (author)

  3. Thermotronics: Towards Nanocircuits to Manage Radiative Heat Flux

    Science.gov (United States)

    Ben-Abdallah, Philippe; Biehs, Svend-Age

    2017-02-01

    The control of electric currents in solids is at the origin of the modern electronics revolution that has driven our daily life since the second half of 20th century. Surprisingly, to date, there is no thermal analogue for a control of heat flux. Here, we summarise the very last developments carried out in this direction to control heat exchanges by radiation both in near and far-field in complex architecture networks.

  4. Thermotronics. Towards nanocircuits to manage radiative heat flux

    International Nuclear Information System (INIS)

    Ben-Abdallah, Philippe; Sherbrooke Univ., PQ; Biehs, Svend-Age

    2017-01-01

    The control of electric currents in solids is at the origin of the modern electronics revolution that has driven our daily life since the second half of 20 th century. Surprisingly, to date, there is no thermal analogue for a control of heat flux. Here, we summarise the very last developments carried out in this direction to control heat exchanges by radiation both in near and far-field in complex architecture networks.

  5. Thermotronics. Towards nanocircuits to manage radiative heat flux

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Abdallah, Philippe [Univ. Paris-Sud 11, Palaiseau (France). Lab. Charles Fabry; Sherbrooke Univ., PQ (Canada). Dept. of Mechanical Engineering; Biehs, Svend-Age [Oldenburg Univ. (Germany). Inst. fuer Physik

    2017-05-01

    The control of electric currents in solids is at the origin of the modern electronics revolution that has driven our daily life since the second half of 20{sup th} century. Surprisingly, to date, there is no thermal analogue for a control of heat flux. Here, we summarise the very last developments carried out in this direction to control heat exchanges by radiation both in near and far-field in complex architecture networks.

  6. Spectral estimates of net radiation and soil heat flux

    International Nuclear Information System (INIS)

    Daughtry, C.S.T.; Kustas, W.P.; Moran, M.S.; Pinter, P.J. Jr.; Jackson, R.D.; Brown, P.W.; Nichols, W.D.; Gay, L.W.

    1990-01-01

    Conventional methods of measuring surface energy balance are point measurements and represent only a small area. Remote sensing offers a potential means of measuring outgoing fluxes over large areas at the spatial resolution of the sensor. The objective of this study was to estimate net radiation (Rn) and soil heat flux (G) using remotely sensed multispectral data acquired from an aircraft over large agricultural fields. Ground-based instruments measured Rn and G at nine locations along the flight lines. Incoming fluxes were also measured by ground-based instruments. Outgoing fluxes were estimated using remotely sensed data. Remote Rn, estimated as the algebraic sum of incoming and outgoing fluxes, slightly underestimated Rn measured by the ground-based net radiometers. The mean absolute errors for remote Rn minus measured Rn were less than 7%. Remote G, estimated as a function of a spectral vegetation index and remote Rn, slightly overestimated measured G; however, the mean absolute error for remote G was 13%. Some of the differences between measured and remote values of Rn and G are associated with differences in instrument designs and measurement techniques. The root mean square error for available energy (Rn - G) was 12%. Thus, methods using both ground-based and remotely sensed data can provide reliable estimates of the available energy which can be partitioned into sensible and latent heat under non advective conditions

  7. Influence of particle flux density and temperature on surface modifications of tungsten and deuterium retention

    Energy Technology Data Exchange (ETDEWEB)

    Buzi, Luxherta, E-mail: l.buzi@fz-juelich.de [Ghent University, Department of Applied Physics, Sint-Pietersnieuwstraat 41, B-9000 Ghent (Belgium); FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Edisonbaan 14, 3439 MN, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Institut für Energie und Klimaforschung – Plasmaphysik, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich (Germany); Université de Lorraine, Institut Jean Lamour, CNRS UMR 7198, Bvd. des Aiguillettes, F-54506 Vandoeuvre (France); Temmerman, Greg De [FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Edisonbaan 14, 3439 MN, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Unterberg, Bernhard; Reinhart, Michael; Litnovsky, Andrey; Philipps, Volker [Institut für Energie und Klimaforschung – Plasmaphysik, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich (Germany); Oost, Guido Van [Ghent University, Department of Applied Physics, Sint-Pietersnieuwstraat 41, B-9000 Ghent (Belgium); Möller, Sören [Institut für Energie und Klimaforschung – Plasmaphysik, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich (Germany)

    2014-12-15

    Systematic study of deuterium irradiation effects on tungsten was done under ITER – relevant high particle flux density, scanning a broad surface temperature range. Polycrystalline ITER – like grade tungsten samples were exposed in linear plasma devices to two different ranges of deuterium ion flux densities (high: 3.5–7 · 10{sup 23} D{sup +}/m{sup 2} s and low: 9 · 10{sup 21} D{sup +}/m{sup 2} s). Particle fluence and ion energy, respectively 10{sup 26} D{sup +}/m{sup 2} and ∼38 eV were kept constant in all cases. The experiments were performed at three different surface temperatures 530 K, 630 K and 870 K. Experimental results concerning the deuterium retention and surface modifications of low flux exposure confirmed previous investigations. At temperatures 530 K and 630 K, deuterium retention was higher at lower flux density due to the longer exposure time (steady state plasma operation) and a consequently deeper diffusion range. At 870 K, deuterium retention was found to be higher at high flux density according to the thermal desorption spectroscopy (TDS) measurements. While blisters were completely absent at low flux density, small blisters of about 40–50 nm were formed at high flux density exposure. At the given conditions, a relation between deuterium retention and blister formation has been found which has to be considered in addition to deuterium trapping in defects populated by diffusion.

  8. Influence of particle flux density and temperature on surface modifications of tungsten and deuterium retention

    International Nuclear Information System (INIS)

    Buzi, Luxherta; Temmerman, Greg De; Unterberg, Bernhard; Reinhart, Michael; Litnovsky, Andrey; Philipps, Volker; Oost, Guido Van; Möller, Sören

    2014-01-01

    Systematic study of deuterium irradiation effects on tungsten was done under ITER – relevant high particle flux density, scanning a broad surface temperature range. Polycrystalline ITER – like grade tungsten samples were exposed in linear plasma devices to two different ranges of deuterium ion flux densities (high: 3.5–7 · 10 23 D + /m 2 s and low: 9 · 10 21 D + /m 2 s). Particle fluence and ion energy, respectively 10 26 D + /m 2 and ∼38 eV were kept constant in all cases. The experiments were performed at three different surface temperatures 530 K, 630 K and 870 K. Experimental results concerning the deuterium retention and surface modifications of low flux exposure confirmed previous investigations. At temperatures 530 K and 630 K, deuterium retention was higher at lower flux density due to the longer exposure time (steady state plasma operation) and a consequently deeper diffusion range. At 870 K, deuterium retention was found to be higher at high flux density according to the thermal desorption spectroscopy (TDS) measurements. While blisters were completely absent at low flux density, small blisters of about 40–50 nm were formed at high flux density exposure. At the given conditions, a relation between deuterium retention and blister formation has been found which has to be considered in addition to deuterium trapping in defects populated by diffusion

  9. Radiation induced defect flux behaviors at zirconium based component

    International Nuclear Information System (INIS)

    Choi, Sang Il; Kim, Ji Hyun; Kwon, Jun Hyun; Lee, Gyeong Geun

    2013-01-01

    In commercial reactor core, structure materials are located in high temperature and high pressure environment. Therefore, main concern of structure materials is corrosion and mechanical properties change than radiation effects on materials. However, radiation effects on materials become more important phenomena because research reactor condition is different from commercial reactor. The temperature is lower than 100 .deg. C and radiation dose is much higher than that of commercial reactor. Among the radiation effect on zirconium based metal, radiation induced growth (RIG), known as volume conservative distortion, is one of the most important phenomena. Recently, theoretical RIG modeling based on radiation damage theory (RDT) and balance equation are developed. However, these growth modeling have limited framework of single crystal and high temperature. To model theoretical RIG in research reactor, qualitative mechanism must be set up. Therefore, this paper intent is establishing defect flux mechanism of zirconium base metal in research reactor for RIG modeling. After than theoretical RIG work will be expanded to research reactor condition

  10. Surface flux density distribution characteristics of bulk high-Tc superconductor in external magnetic field

    International Nuclear Information System (INIS)

    Torii, S.; Yuasa, K.

    2004-01-01

    Various magnetic levitation systems using oxide superconductors are developed as strong pinning forces are obtained in melt-processed bulk. However, the trapped flux of superconductor is moved by flux creep and fluctuating magnetic field. Therefore, to examine the internal condition of superconductor, the authors measure the dynamic surface flux density distribution of YBCO bulk. Flux density measurement system has a structure with the air-core coil and the Hall sensors. Ten Hall sensors are arranged in series. The YBCO bulk, which has 25 mm diameter and 13 mm thickness, is field cooled by liquid nitrogen. After that, magnetic field is changed by the air-core coil. This paper describes about the measured results of flux density distribution of YBCO bulk in the various frequencies of air-core coils currents

  11. Surface flux density distribution characteristics of bulk high- Tc superconductor in external magnetic field

    Science.gov (United States)

    Torii, S.; Yuasa, K.

    2004-10-01

    Various magnetic levitation systems using oxide superconductors are developed as strong pinning forces are obtained in melt-processed bulk. However, the trapped flux of superconductor is moved by flux creep and fluctuating magnetic field. Therefore, to examine the internal condition of superconductor, the authors measure the dynamic surface flux density distribution of YBCO bulk. Flux density measurement system has a structure with the air-core coil and the Hall sensors. Ten Hall sensors are arranged in series. The YBCO bulk, which has 25 mm diameter and 13 mm thickness, is field cooled by liquid nitrogen. After that, magnetic field is changed by the air-core coil. This paper describes about the measured results of flux density distribution of YBCO bulk in the various frequencies of air-core coils currents.

  12. Neutral particle and radiation effects on Pfirsch - Schlueter fluxes near the edge

    International Nuclear Information System (INIS)

    Catto, P.J.; Helander, P.; Connor, J.W.; Hazeltine, R.D.

    1998-01-01

    The edge plasma of a tokamak is affected by atomic physics processes and can have density and temperature variations along the magnetic field that strongly modify edge transport. A closed system of equations in the Pfirsch - Schlueter regime is presented that can be solved for the radial and poloidal variation of the plasma density, electron and ion temperatures, and the electrostatic potential in the presence of neutrals and a poloidally asymmetric energy radiation sink due to inelastic electron collisions. Neutrals have a large diffusivity so their viscosity and heat flux can become important even when their density is not high, in which case the neutral viscosity alters the electrostatic potential at the edge by introducing strong radial variation. The strong parallel gradient in the electron temperature that can arise in the presence of a localized radiation sink drives a convective flow of particles and heat across the field. This plasma transport mechanism can balance the neutral influx and is particularly strong if multifaceted asymmetric radiation from the edge (MARFE) occurs, since the electron temperature then varies substantially over the flux surface. copyright 1998 American Institute of Physics

  13. Linearized Flux Evolution (LiFE): A technique for rapidly adapting fluxes from full-physics radiative transfer models

    Science.gov (United States)

    Robinson, Tyler D.; Crisp, David

    2018-05-01

    Solar and thermal radiation are critical aspects of planetary climate, with gradients in radiative energy fluxes driving heating and cooling. Climate models require that radiative transfer tools be versatile, computationally efficient, and accurate. Here, we describe a technique that uses an accurate full-physics radiative transfer model to generate a set of atmospheric radiative quantities which can be used to linearly adapt radiative flux profiles to changes in the atmospheric and surface state-the Linearized Flux Evolution (LiFE) approach. These radiative quantities describe how each model layer in a plane-parallel atmosphere reflects and transmits light, as well as how the layer generates diffuse radiation by thermal emission and by scattering light from the direct solar beam. By computing derivatives of these layer radiative properties with respect to dynamic elements of the atmospheric state, we can then efficiently adapt the flux profiles computed by the full-physics model to new atmospheric states. We validate the LiFE approach, and then apply this approach to Mars, Earth, and Venus, demonstrating the information contained in the layer radiative properties and their derivatives, as well as how the LiFE approach can be used to determine the thermal structure of radiative and radiative-convective equilibrium states in one-dimensional atmospheric models.

  14. Influence of surface conditions in nucleate boiling--the concept of bubble flux density

    International Nuclear Information System (INIS)

    Shoukri, M.; Judd, R.L.

    1978-01-01

    A study of the influence of surface conditions in nucleate pool boiling is presented. The surface conditions are represented by the number and distribution of the active nucleation sites as well as the size and size distribution of the cavities that constitute the nucleation sites. The heat transfer rate during nucleate boiling is shown to be influenced by the surface condition through its effect on the number and distribution of the active nucleation sites as well as the frequency of bubble departure from each of these different size cavities. The concept of bubble flux density, which is a function of both the active site density and frequency of bubble departure, is introduced. A method of evaluating the bubble flux density is proposed and a uniform correlation between the boiling heat flux and the bubble flux density is found to exist for a particular solid-liquid combination irrespective of the surface finish within the region of isolated bubbles

  15. Transport calculations of. gamma. -ray flux density and dose rate about implantable californium-252 sources

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, A; Lin, B I [Cincinnati Univ., Ohio (USA). Dept. of Chemical and Nuclear Engineering; Windham, J P; Kereiakes, J G

    1976-07-01

    ..gamma.. flux density and dose rate distributions have been calculated about implantable californium-252 sources for an infinite tissue medium. Point source flux densities as a function of energy and position were obtained from a discrete-ordinates calculation, and the flux densities were multiplied by their corresponding kerma factors and added to obtain point source dose rates. The point dose rates were integrated over the line source to obtain line dose rates. Container attenuation was accounted for by evaluating the point dose rate as a function of platinum thickness. Both primary and secondary flux densities and dose rates are presented. The agreement with an independent Monte Carlo calculation was excellent. The data presented should be useful for the design of new source configurations.

  16. Study of errors in absolute flux density measurements of Cassiopeia A

    International Nuclear Information System (INIS)

    Kanda, M.

    1975-10-01

    An error analysis for absolute flux density measurements of Cassiopeia A is discussed. The lower-bound quadrature-accumulation error for state-of-the-art measurements of the absolute flux density of Cas A around 7 GHz is estimated to be 1.71% for 3 sigma limits. The corresponding practicable error for the careful but not state-of-the-art measurement is estimated to be 4.46% for 3 sigma limits

  17. The causal relation between turbulent particle flux and density gradient

    Energy Technology Data Exchange (ETDEWEB)

    Milligen, B. Ph. van; Martín de Aguilera, A.; Hidalgo, C. [CIEMAT - Laboratorio Nacional de Fusión, Avda. Complutense 40, 28040 Madrid (Spain); Carreras, B. A. [BACV Solutions, 110 Mohawk Road, Oak Ridge, Tennessee 37830 (United States); García, L.; Nicolau, J. H. [Universidad Carlos III, 28911 Leganés, Madrid (Spain)

    2016-07-15

    A technique for detecting the causal relationship between fluctuating signals is used to investigate the relation between flux and gradient in fusion plasmas. Both a resistive pressure gradient driven turbulence model and experimental Langmuir probe data from the TJ-II stellarator are studied. It is found that the maximum influence occurs at a finite time lag (non-instantaneous response) and that quasi-periodicities exist. Furthermore, the model results show very long range radial influences, extending over most of the investigated regions, possibly related to coupling effects associated with plasma self-organization. These results clearly show that transport in fusion plasmas is not local and instantaneous, as is sometimes assumed.

  18. Transfer matrix method for four-flux radiative transfer.

    Science.gov (United States)

    Slovick, Brian; Flom, Zachary; Zipp, Lucas; Krishnamurthy, Srini

    2017-07-20

    We develop a transfer matrix method for four-flux radiative transfer, which is ideally suited for studying transport through multiple scattering layers. The model predicts the specular and diffuse reflection and transmission of multilayer composite films, including interface reflections, for diffuse or collimated incidence. For spherical particles in the diffusion approximation, we derive closed-form expressions for the matrix coefficients and show remarkable agreement with numerical Monte Carlo simulations for a range of absorption values and film thicknesses, and for an example multilayer slab.

  19. Estimating the amount and distribution of radon flux density from the soil surface in China

    International Nuclear Information System (INIS)

    Zhuo Weihai; Guo Qiuju; Chen Bo; Cheng Guan

    2008-01-01

    Based on an idealized model, both the annual and the seasonal radon ( 222 Rn) flux densities from the soil surface at 1099 sites in China were estimated by linking a database of soil 226 Ra content and a global ecosystems database. Digital maps of the 222 Rn flux density in China were constructed in a spatial resolution of 25 km x 25 km by interpolation among the estimated data. An area-weighted annual average 222 Rn flux density from the soil surface across China was estimated to be 29.7 ± 9.4 mBq m -2 s -1 . Both regional and seasonal variations in the 222 Rn flux densities are significant in China. Annual average flux densities in the southeastern and northwestern China are generally higher than those in other regions of China, because of high soil 226 Ra content in the southeastern area and high soil aridity in the northwestern one. The seasonal average flux density is generally higher in summer/spring than winter, since relatively higher soil temperature and lower soil water saturation in summer/spring than other seasons are common in China

  20. Measuring the Magnetic Flux Density in the CMS Steel Yoke

    CERN Document Server

    Klyukhin, V I; Ball, A; Curé, B; Gaddi, A; Gerwig, H; Hervé, A; Mulders, M; Loveless, R

    2012-01-01

    The Compact Muon Solenoid (CMS) is a general purpose detector, designed to run at the highest luminosity at the CERN Large Hadron Collider (LHC). Its distinctive features include a 4 T superconducting solenoid with 6-m-diameter by 12.5-m-length free bore, enclosed inside a 10000-ton return yoke made of construction steel. The return yoke consists of five dodecagonal three-layered barrel wheels and four end-cap disks at each end comprised of steel blocks up to 620 mm thick, which serve as the absorber plates of the muon detection system. Accurate characterization of the magnetic field everywhere in the CMS detector is required. To measure the field in and around the steel, a system of 22 flux-loops and 82 3-D Hall sensors is installed on the return yoke blocks. Fast discharges of the solenoid (190 s time-constant) made during the CMS magnet surface commissioning test at the solenoid central fields of 2.64, 3.16, 3.68 and 4.01 T were used to induce voltages in the flux-loops. The voltages are measured on-line a...

  1. Influence of Sky Conditions on Estimation of Photosynthetic Photon Flux Density for Agricultural Ecosystem

    Science.gov (United States)

    Yamashita, M.; Yoshimura, M.

    2018-04-01

    Photosynthetic photon flux density (PPFD: µmol m-2 s-1) is indispensable for plant physiology processes in photosynthesis. However, PPFD is seldom measured, so that PPFD has been estimated by using solar radiation (SR: W m-2) measured in world wide. In method using SR, there are two steps: first to estimate photosynthetically active radiation (PAR: W m-2) by the fraction of PAR to SR (PF) and second: to convert PAR to PPFD using the ratio of quanta to energy (Q / E: µmol J-1). PF and Q/E usually have been used as the constant values, however, recent studies point out that PF and Q / E would not be constants under various sky conditions. In this study, we use the numeric data of sky-conditions factors such cloud cover, sun appearance/hiding and relative sky brightness derived from whole-sky image processing and examine the influences of sky-conditions factors on PF and Q / E of global and diffuse PAR. Furthermore, we discuss our results by comparing with the existing methods.

  2. Measuring neutron flux density in near-vessel space of a commercial WWER-1000 reactor

    International Nuclear Information System (INIS)

    Borodkin, G.I.; Eremin, A.N.; Lomakin, S.S.; Morozov, A.G.

    1987-01-01

    Distribution of neutron flux density in two experimental channels on the reactor vessel external surface and in ionization chamber channel of a commercial WWER-1000 reactor, is measured by the activation detector technique. Azimuthal distributions of fast and thermal neutron fluxes and height distributions of fast neutron flux density within energy range >1.2 and 2.3 MeV are obtained. Conclusion is made, that reactor core state and its structural peculiarities in the measurement range essentially affect space and energy distribution of neutron field near the vessel. It should be taken into account when determining permissible neutron fluence for the reactor vessel

  3. Modeling hemispherical and directional radiative fluxes in regular-clumped canopies

    International Nuclear Information System (INIS)

    Begue, A.

    1992-01-01

    A model of radiative transfer in regular-clumped canopies is presented. The canopy is approximated by an array of porous cylinders located at the vertices of equilateral triangles. The model is split into two submodels, each describing a different level of structure: 1) The macrostructure submodel is based on Brown and Pandolfo (1969), who applied geometrical optics theory to an array of opaque cylinders. This model is adapted for porous cylinders and is used to derive expressions for directional interception efficiency as a function of height, radius, spacing and porosity of the cylinders. 2) The microstructure submodel makes use of the average canopy transmittance theory, applied to a cylinder, to compute the porosity of the clumps as a function of the leaf area density, the leaf inclination distribution function, the dimensions of the cylinder (height and radius), and the transmittance of green leaves in the appropriate spectral band. It is shown that, in the case of erectophile plant stands, the daily porosity of the cylinder can be approximated by the porosity calculated using the extinction coefficient of diffuse radiation. Directional interception efficiency, geometric conditions (incidence/viewing), and landscape component reflectances are used to compute hemispherical (interception, absorption, and reflectance) and directional (reflectance) radiative fluxes from simple analytical formulae. This model is validated against a data set of biological, radiative (PAR region) and radiometric (SPOT channels) measurements, collected in Niger on pearl millet (Pennisetum typhoides). The model fits the data quite well in terms of hourly and daily single-band or combined (NDVI) radiative fluxes. Close correspondence to measured fluxes, using few parameters, and the possibility of inversion makes the present model a valuable tool for the study of radiative transfer in discontinuous canopies. (author)

  4. Determination of neutron flux densities in WWR-S reactor core

    International Nuclear Information System (INIS)

    Tomasek, F.

    1989-04-01

    The method is described of determining neutron flux densities and neutron fluences using activation detectors. The basic definitions and relations for determining reaction rates, fluence and neutron flux as well as the characteristics of some reactions and of sitable activation detectors are reported. The flux densities were determined of thermal and fast neutrons and of gamma quanta in the WWR-S reactor core. The data measured in the period 1984-1987 are tabulated. Cross sections for the individual reactions were determined from spectra measurements processed using program SAND-II and cross section library ENDF-B IV. Neutron flux densities were also measured for the WWR-S reactor vertical channels. (E.J.). 10 figs., 8 tabs., 111 refs

  5. Atmospheric Renewable Energy Research, Volume 5 (Solar Radiation Flux Model)

    Science.gov (United States)

    2017-09-01

    sources, namely photovoltaic (PV) panels, to roughly determine the energy producing potential of an installation’s solar array. The implicit...power resources assembled as a single system (generator, storage, distribution and load), with the ability to run independently as an “island” and/or...atmospheric layers that will act on the solar radiation as it traverses strata. These terms are a function of cloud type, size , and density. To create a

  6. Flux depression and the absolute measurement of the thermal neutron flux density

    International Nuclear Information System (INIS)

    Bensch, Friedrich.

    1977-01-01

    The thermal neutron flux depression in a diffusing medium by an absorbing foil has been treated in numerous papers. The results are re-examined in an attempt to find a uniform and physically meaningful representation of the 'activation correction'. This quantity can be split up into a combination of probabilities. Thus, it is possible to determine the activation correction for any moderator and foil material. Measurements confirm the utility of the concepts introduced

  7. Expansion Of The Magnetic Flux Density Field In Toroidal Harmonics

    CERN Document Server

    AUTHOR|(CDS)2290414; Bottura, Luca; Felcini, Enrico

    CERN (Conseil Européen pour la Recherche Nucléaire) is recognized worldwide as the main research laboratory in the field of particle physics. Inevitably, all this requires the use of the most advanced technologies, both from the point of view of the instruments and the analytical descriptive methods. One of the numerous potentials of the work carried out at CERN concerns the possibility of exploiting the aforementioned technologies even in contexts distant from the physics of particles, with the result of influencing the technological advancement of many areas. For example, one of the most widely employed theories at CERN, regarding the analytical description of the magnetic flux density inside solenoidal magnets (or approximable as such under suitable assumptions) for the acceleration of particles, is the so-called multipole expansion. This is a two-dimensional or three-dimensional analysis of the distribution of the magnetic flux density generated by the windings of a magnet. The magnet in question ca...

  8. Multiple-capillary measurement of RBC speed, flux, and density with optical coherence tomography.

    Science.gov (United States)

    Lee, Jonghwan; Wu, Weicheng; Lesage, Frederic; Boas, David A

    2013-11-01

    As capillaries exhibit heterogeneous and fluctuating dynamics even during baseline, a technique measuring red blood cell (RBC) speed and flux over many capillaries at the same time is needed. Here, we report that optical coherence tomography can capture individual RBC passage simultaneously over many capillaries located at different depths. Further, we demonstrate the ability to quantify RBC speed, flux, and linear density. This technique will provide a means to monitor microvascular flow dynamics over many capillaries at different depths at the same time.

  9. Research and Evaluation of the Energy Flux Density of the Mobile Phone Electromagnetic Field

    Directory of Open Access Journals (Sweden)

    Pranas Baltrėnas

    2012-12-01

    Full Text Available The article analyses variations in the energy flux density of the electromagnetic field of 10 mobile phones depending on distance. The studies have been conducted using three modes: sending a text message, receiving a text message and connecting a mobile phone to the Internet. When text messages are received or sent from a mobile phone, the values of the energy flux density of the mobile phone electromagnetic field exceed the safe allowable limit and make 10 μW / cm². A distance of 10, 20 and 30 cm from a mobile phone is effective protection against the energy flux density of the electromagnetic field when writing texts, receiving messages or connecting to the mobile Internet.Article in Lithuanian

  10. Minnealloy: a new magnetic material with high saturation flux density and low magnetic anisotropy

    Science.gov (United States)

    Mehedi, Md; Jiang, Yanfeng; Suri, Pranav Kumar; Flannigan, David J.; Wang, Jian-Ping

    2017-09-01

    We are reporting a new soft magnetic material with high saturation magnetic flux density, and low magnetic anisotropy. The new material is a compound of iron, nitrogen and carbon, α‧-Fe8(NC), which has saturation flux density of 2.8  ±  0.15 T and magnetic anisotropy of 46 kJ m-3. The saturation flux density is 27% higher than pure iron, a widely used soft magnetic material. Soft magnetic materials are very important building blocks of motors, generators, inductors, transformers, sensors and write heads of hard disk. The new material will help in the miniaturization and efficiency increment of the next generation of electronic devices.

  11. Effect of the Heat Flux Density on the Evaporation Rate of a Distilled Water Drop

    Directory of Open Access Journals (Sweden)

    Ponomarev Konstantin

    2016-01-01

    Full Text Available This paper presents the experimental dependence of the evaporation rate of a nondeaerated distilled water drop from the heat flux density on the surfaces of non-ferrous metals (copper and brass. A drop was placed on a heated substrate by electronic dosing device. To obtain drop profile we use a shadow optical system; drop symmetry was controlled by a high-speed video camera. It was found that the evaporation rate of a drop on a copper substrate is greater than on a brass. The evaporation rate increases intensively with raising volume of a drop. Calculated values of the heat flux density and the corresponding evaporation rates are presented in this work. The evaporation rate is found to increase intensively on the brass substrate with raising the heat flux density.

  12. Radiation dosimetry at the BNL High Flux Beam Reactor

    International Nuclear Information System (INIS)

    Holden, N.E.; Hu, J.P.; Reciniello, R.N.

    1998-02-01

    The HFBR is a heavy water, D 2 O, cooled and moderated reactor with twenty-eight fuel elements containing a maximum of 9.8 kilograms of 235 U. The core is 53 cm high and 48 cm in diameter and has an active volume of 97 liters. The HFBR, which was designed to operate at forty mega-watts, 40 NW, was upgraded to operate at 60 NW. Since 1991, it has operated at 30 MW. In a normal 30 MW operating cycle the HFBR operates 24 hours a day for thirty days, with a six to fourteen day shutdown period for refueling and maintenance work. While most reactors attempts to minimize the escape of neutrons from the core, the HFBR's D 2 O design allows the thermal neutron flux to peak in the reflector region and maximizes the number of thermal neutrons available to nine horizontal external beams, H-1 to H-9. The HFBR neutron dosimetry effort described here compares measured and calculated energy dependent neutron and gamma ray flux densities and/or dose rates at horizontal beam lines and vertical irradiation thimbles

  13. Surface flux density distribution characteristics of bulk high-T c superconductor in external magnetic field

    International Nuclear Information System (INIS)

    Nishikawa, H.; Torii, S.; Yuasa, K.

    2005-01-01

    This paper describes the measured results of the two-dimensional flux density distribution of a YBCO bulk under applied AC magnetic fields with various frequency. Melt-processed oxide superconductors have been developed in order to obtain strong pinning forces. Various electric mechanical systems or magnetic levitation systems use those superconductors. The major problem is that cracks occur because the bulk superconductors are brittle. The bulk may break in magnetizing process after cracks make superconducting state instable. The trapped flux density and the permanent current characteristics of bulk superconductors have been analyzed, so as to examine the magnetizing processes or superconducting states of the bulk. In those studies, the two-dimensional surface flux density distributions of the bulk in static fields are discussed. On the other hand, the distributions in dynamic fields are little discussed. We attempted to examine the states of the bulk in the dynamic fields, and made a unique experimental device which has movable sensors synchronized with AC applied fields. As a result, the two-dimensional distributions in the dynamic fields are acquired by recombining the one-dimensional distributions. The dynamic states of the flux of the bulk and the influences of directions of cracks are observed from the distributions. In addition, a new method for measuring two-dimensional flux density distribution under dynamic magnetic fields is suggested

  14. Neutron flux density data acquisition system based on LabVIEW

    International Nuclear Information System (INIS)

    Zhao Yanhui; Zhao Xiuliang; Li Zonglun; Liang Fengyan; Liu Liyan

    2011-01-01

    In the LabVIEW software, combined with PCI-6251 data acquisition card, VI of neutron flux density data acquisition is realized by DAQmx data acquisition functions. VI is composed of front panel and block diagram. The data collected can be displayed in the forms of the data curve and the data control, and saved in the form of files. Test results show that the frequency of output signal in NI ELVIS can be accurately measured by the system, realizing neutron flux density data acquisition based on LabVIEW. (authors)

  15. Flux and brightness calculations for various synchrotron radiation sources

    International Nuclear Information System (INIS)

    Weber, J.M.; Hulbert, S.L.

    1991-11-01

    Synchrotron radiation (SR) storage rings are powerful scientific and technological tools. The first generation of storage rings in the US., e.g., SURF (Washington, D.C.), Tantalus (Wisconsin), SSRL (Stanford), and CHESS (Cornell), revolutionized VUV, soft X-ray, and hard X-ray science. The second (present) generation of storage rings, e.g. the NSLS VUV and XRAY rings and Aladdin (Wisconsin), have sustained the revolution by providing higher stored currents and up to a factor of ten smaller electron beam sizes than the first generation sources. This has made possible a large number of experiments that could not performed using first generation sources. In addition, the NSLS XRAY ring design optimizes the performance of wigglers (high field periodic magnetic insertion devices). The third generation storage rings, e.g. ALS (Berkeley) and APS (Argonne), are being designed to optimize the performance of undulators (low field periodic magnetic insertion devices). These extremely high brightness sources will further revolutionize x-ray science by providing diffraction-limited x-ray beams. The output of undulators and wigglers is distinct from that of bending magnets in magnitude, spectral shape, and in spatial and angular size. Using published equations, we have developed computer programs to calculate the flux, central intensity, and brightness output bending magnets and selected wigglers and undulators of the NSLS VUV and XRAY rings, the Advanced Light Source (ALS), and the Advanced Photon Source (APS). Following is a summary of the equations used, the graphs and data produced, and the computer codes written. These codes, written in the C programming language, can be used to calculate the flux, central intensity, and brightness curves for bending magnets and insertion devices on any storage ring

  16. An experimental study of radiative fluxes in the south Bay of Bengal

    Indian Academy of Sciences (India)

    Time series measurements of radiative fluxes were made onboard INS Sagardhwani (SD) in the south Bay of Bengal near DS3 (13°N and 87°E) during the BOBMEX field experiment. An inter- comparison experiment conducted at DS3 showed that the radiative fluxes measured by Kipp and Zonen, Albedo meter and net ...

  17. Precipitated Fluxes of Radiation Belt Electrons via Injection of Whistler-Mode Waves

    Science.gov (United States)

    Kulkarni, P.; Inan, U. S.; Bell, T. F.

    2005-12-01

    Inan et al. (U.S. Inan et al., Controlled precipitation of radiation belt electrons, Journal of Geophysical Research-Space Physics, 108 (A5), 1186, doi: 10.1029/2002JA009580, 2003.) suggested that the lifetime of energetic (a few MeV) electrons in the inner radiation belts may be moderated by in situ injection of whistler mode waves at frequencies of a few kHz. We use the Stanford 2D VLF raytracing program (along with an accurate estimation of the path-integrated Landau damping based on data from the HYDRA instrument on the POLAR spacecraft) to determine the distribution of wave energy throughout the inner radiation belts as a function of injection point, wave frequency and injection wave normal angle. To determine the total wave power injected and its initial distribution in k-space (i.e., wave-normal angle), we apply the formulation of Wang and Bell ( T.N.C. Wang and T.F. Bell, Radiation resistance of a short dipole immersed in a cold magnetoionic medium, Radio Science, 4 (2), 167-177, February 1969) for an electric dipole antenna placed at a variety of locations throughout the inner radiation belts. For many wave frequencies and wave normal angles the results establish that most of the radiated power is concentrated in waves whose wave normals are located near the resonance cone. The combined use of the radiation pattern and ray-tracing including Landau damping allows us to make quantitative estimates of the magnetospheric distribution of wave power density for different source injection points. We use these results to estimate the number of individual space-based transmitters needed to significantly impact the lifetimes of energetic electrons in the inner radiation belts. Using the wave power distribution, we finally determine the energetic electron pitch angle scattering and the precipitated flux signatures that would be detected.

  18. Exospheric density and escape fluxes of atomic isotopes on Venus and Mars

    International Nuclear Information System (INIS)

    Wallis, M.K.

    1978-01-01

    Energetic neutrals in dissociative recombinations near or above the exobase provided an important component of exospheric density and escape fluxes. Plasma thermal velocities provide the main contribution to the velocity spread and an exact integral for the escape flux applicable in marginal cases is found for a simple atmosphere and collisional cut-off. Atomic fragments from recombination of diatomic oxygen and nitrogen ions in the Venus and Mars atmospheres are examined and density integrals derived. The oxygen escape flux on Mars is half that previously estimated and there is very little isotope preference supplementing diffusive separation. However, escape of the heavier 15 N isotope is low by a factor two. Reinterpretation of its 75% enrichment as detected by Viking leads to a range 0.4-1.4 mbar for the primeval nitrogen content on Mars. (author)

  19. Comparison of VLBI radio core and X-ray flux densities of extragalactic radio sources

    International Nuclear Information System (INIS)

    Bloom, S.D.; Marscher, A.P.

    1990-01-01

    The Einstein Observatory revealed that most quasars, selected in a variety of ways, are strong x-ray emitters. Radio bright quasars are statistically more luminous in the x-ray than their radio-quiet counterparts. It was also found that the 90 GHz to soft x-ray spectral index has a very small dispersion for sources selected by their strong millimeter emission. This implies a close relationship between compact radio flux density and x-ray emission. Strong correlations have been found between the arcsecond scale flux densities and soft x-ray fluxes. It is suggested that the correlation can be explained if the soft x-rays were produced by the synchrotron self-Compton (SSC) process within the compact radio emitting region. (author)

  20. Current density waves in open mesoscopic rings driven by time-periodic magnetic fluxes

    International Nuclear Information System (INIS)

    Yan Conghua; Wei Lianfu

    2010-01-01

    Quantum coherent transport through open mesoscopic Aharonov-Bohm rings (driven by static fluxes) have been studied extensively. Here, by using quantum waveguide theory and the Floquet theorem we investigate the quantum transport of electrons along an open mesoscopic ring threaded by a time-periodic magnetic flux. We predicate that current density waves could be excited along such an open ring. As a consequence, a net current could be generated along the lead with only one reservoir, if the lead additionally connects to such a normal-metal loop driven by the time-dependent flux. These phenomena could be explained by photon-assisted processes, due to the interaction between the transported electrons and the applied oscillating external fields. We also discuss how the time-average currents (along the ring and the lead) depend on the amplitude and frequency of the applied oscillating fluxes.

  1. The neutrons flux density calculations by Monte Carlo code for the double heterogeneity fuel

    International Nuclear Information System (INIS)

    Gurevich, M.I.; Brizgalov, V.I.

    1994-01-01

    This document provides the calculation technique for the fuel elements which consists of the one substance as a matrix and the other substance as the corn embedded in it. This technique can be used in the neutron flux density calculation by the universal Monte Carlo code. The estimation of accuracy is presented too. (authors). 6 refs., 1 fig

  2. Behaviour of carbon dioxide and water vapour flux densities from a disturbed raised peat bog

    NARCIS (Netherlands)

    Nieveen, J.P.; Jacobs, A.F.G.

    2002-01-01

    Measurements of carbon dioxide and water vapour flux densities were carried out for a disturbed raised peat bog in the north of the Netherlands during an 18 month continuous experiment. Tussock grass (sp. Molinea caerulae) mainly dominated the vegetation of the bog area. The maximum leaf area index

  3. Wood fibre density measurement with 238 Pu radiation

    International Nuclear Information System (INIS)

    Barry, B.J.; Baker, D.B.

    1996-01-01

    The form of the curve of attenuation by wood fibre of the X radiation from 238 Pu has been determined. An exponential function containing a term second order in the areal density of the fibre described the curve accurately. The effect of scatter is negligible, even with an uncollimated radiation beam. (author). 18 refs., 1 tab., 6 figs

  4. Alpha radiation gauge for the measurement of gas density

    International Nuclear Information System (INIS)

    Lech, M.

    1977-01-01

    Alpha gauge for the measurement of gas density with thick alfa source, has been developed. The gauge is based on radiation transmission through a space filled with gas and total-count principle. Air density can be measured in the range 1,2 - 1,27 kg m -3 with a maximum standard deviation of 2 x 10 -3 kg m -3 . (author)

  5. Density meters utilizing ionizing radiation: definitions and test methods

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This standard is applicable to density meters utilizing ionizing radiation, designed for the measurement of the density of liquids, slurries or fluidized solids. The standard applies to transmission-type instruments only. Reference to compliance with this standard shall identify any deviations and the reasons for such deviations. Safety aspects are not included but should fulfill the requirements of all relevant internationally accepted standards

  6. Practical difficulties in determining 222Rn flux density in underground uranium mines

    International Nuclear Information System (INIS)

    Bigu, J.

    1991-01-01

    Radon-222 flux density, J, has been determined in a number of locations in an underground U mine. Measurements were conducted using the Two-Point Measurement (2PM) method, consisting of measuring the 222Rn concentration at two different points a distance apart within a given section of the mine. Several mine models were used for determining J by the above method. The 2PM method is sensitive to sources and sinks of 222Rn other than mine walls, as well as mining operations and mining activities of a diverse nature, and to local variations in airflow conditions. Because of this, J obtained by the 2PM method represents an 'apparent' flux density. Significant differences were found in the flux density calculated according to different mine models. In addition, J measurements using the flux 'can' method were also carried out in mine walls and compared with the values obtained by the 2PM method. Wide discrepancies between the two methods were found. The practical and theoretical difficulties in determining J are discussed

  7. Fast Radio Bursts’ Recipes for the Distributions of Dispersion Measures, Flux Densities, and Fluences

    Science.gov (United States)

    Niino, Yuu

    2018-05-01

    We investigate how the statistical properties of dispersion measure (DM) and apparent flux density/fluence of (nonrepeating) fast radio bursts (FRBs) are determined by unknown cosmic rate density history [ρ FRB(z)] and luminosity function (LF) of the transient events. We predict the distributions of DMs, flux densities, and fluences of FRBs taking account of the variation of the receiver efficiency within its beam, using analytical models of ρ FRB(z) and LF. Comparing the predictions with the observations, we show that the cumulative distribution of apparent fluences suggests that FRBs originate at cosmological distances and ρ FRB increases with redshift resembling the cosmic star formation history (CSFH). We also show that an LF model with a bright-end cutoff at log10 L ν (erg s‑1 Hz‑1) ∼ 34 are favored to reproduce the observed DM distribution if ρ FRB(z) ∝ CSFH, although the statistical significance of the constraints obtained with the current size of the observed sample is not high. Finally, we find that the correlation between DM and flux density of FRBs is potentially a powerful tool to distinguish whether FRBs are at cosmological distances or in the local universe more robustly with future observations.

  8. Optimization of multiply acquired magnetic flux density Bz using ICNE-Multiecho train in MREIT

    International Nuclear Information System (INIS)

    Nam, Hyun Soo; Kwon, Oh In

    2010-01-01

    The aim of magnetic resonance electrical impedance tomography (MREIT) is to visualize the electrical properties, conductivity or current density of an object by injection of current. Recently, the prolonged data acquisition time when using the injected current nonlinear encoding (ICNE) method has been advantageous for measurement of magnetic flux density data, Bz, for MREIT in the signal-to-noise ratio (SNR). However, the ICNE method results in undesirable side artifacts, such as blurring, chemical shift and phase artifacts, due to the long data acquisition under an inhomogeneous static field. In this paper, we apply the ICNE method to a gradient and spin echo (GRASE) multi-echo train pulse sequence in order to provide the multiple k-space lines during a single RF pulse period. We analyze the SNR of the measured multiple B z data using the proposed ICNE-Multiecho MR pulse sequence. By determining a weighting factor for B z data in each of the echoes, an optimized inversion formula for the magnetic flux density data is proposed for the ICNE-Multiecho MR sequence. Using the ICNE-Multiecho method, the quality of the measured magnetic flux density is considerably increased by the injection of a long current through the echo train length and by optimization of the voxel-by-voxel noise level of the B z value. Agarose-gel phantom experiments have demonstrated fewer artifacts and a better SNR using the ICNE-Multiecho method. Experimenting with the brain of an anesthetized dog, we collected valuable echoes by taking into account the noise level of each of the echoes and determined B z data by determining optimized weighting factors for the multiply acquired magnetic flux density data.

  9. Study on radiation flux of the receiver with a parabolic solar concentrator system

    International Nuclear Information System (INIS)

    Mao, Qianjun; Shuai, Yong; Yuan, Yuan

    2014-01-01

    Highlights: • The idea of integral dish and multi-dishes in a parabolic solar collector has been proposed. • The impacts of three factors of the receiver have been investigated. • The radiation flux distribution can benefit from a large system error. - Abstract: The solar receiver plays a key role in the performance of a solar dish electric generator. Its radiation flux distribution can directly affect the efficiency of the parabolic solar concentrator system. In this paper, radiation flux distribution of the receiver is simulated successfully using MCRT method. The impacts of incident solar irradiation, aspect ratio (the ratio of the receiver height to the receiver diameter), and system error on the radiation flux of the receiver are investigated. The parameters are studied in the following ranges: incident solar irradiation from 100 to 1100 W/m 2 , receiver aspect ratio from 0.5 to 1.5, and the system error from 0 to 10 mrad. A non-dimensional parameter Θ is defined to represent the ratio of radiation flux to incident solar irradiation. The results show that the maximum of Θ is about 200 in simulation conditions. The aspect ratio and system error have a significant impact on the radiation flux. The optimal receiver aspect ratio is 1.5 at a constant incident solar irradiation, and the maximum of radiation flux increases with decreasing system error, however, the radiation flux distribution can benefit from a large system error. Meanwhile, effects of integral dish and multi-dishes on the radiation flux distribution have been investigated. The results show that the accuracy of two cases can be ignored within the same parameters

  10. PERFORMANCE OPTIMIZATION OF LINEAR INDUCTION MOTOR BY EDDY CURRENT AND FLUX DENSITY DISTRIBUTION ANALYSIS

    Directory of Open Access Journals (Sweden)

    M. S. MANNA

    2011-12-01

    Full Text Available The development of electromagnetic devices as machines, transformers, heating devices confronts the engineers with several problems. For the design of an optimized geometry and the prediction of the operational behaviour an accurate knowledge of the dependencies of the field quantities inside the magnetic circuits is necessary. This paper provides the eddy current and core flux density distribution analysis in linear induction motor. Magnetic flux in the air gap of the Linear Induction Motor (LIM is reduced to various losses such as end effects, fringes, effect, skin effects etc. The finite element based software package COMSOL Multiphysics Inc. USA is used to get the reliable and accurate computational results for optimization the performance of Linear Induction Motor (LIM. The geometrical characteristics of LIM are varied to find the optimal point of thrust and minimum flux leakage during static and dynamic conditions.

  11. Development of an Axial Flux MEMS BLDC Micromotor with Increased Efficiency and Power Density

    Directory of Open Access Journals (Sweden)

    Xiaofeng Ding

    2015-06-01

    Full Text Available This paper presents a rigorous design and optimization of an axial flux microelectromechanical systems (MEMS brushless dc (BLDC micromotor with dual rotor improving both efficiency and power density with an external diameter of only around 10 mm. The stator is made of two layers of windings by MEMS technology. The rotor is developed by film permanent magnets assembled over the rotor yoke. The characteristics of the MEMS micromotor are analyzed and modeled through a 3-D magnetic equivalent circuit (MEC taking the leakage flux and fringing effect into account. Such a model yields a relatively accurate prediction of the flux in the air gap, back electromotive force (EMF and electromagnetic torque, whilst being computationally efficient. Based on 3-D MEC model the multi-objective firefly algorithm (MOFA is developed for the optimal design of this special machine. Both 3-D finite element (FE simulation and experiments are employed to validate the MEC model and MOFA optimization design.

  12. Measurement of 2D vector magnetic properties under the distorted flux density conditions

    International Nuclear Information System (INIS)

    Urata, Shinya; Todaka, Takashi; Enokizono, Masato; Maeda, Yoshitaka; Shimoji, Hiroyasu

    2006-01-01

    Under distorted flux density condition, it is very difficult to evaluate the field intensity, because there is no criterion for the measurement. In the linear approximation, the measured field intensity waveform (MFI) is compared with the linear synthesis of field intensity waveform (LSFI) in each frequency, and it is shown that they are not in good agreement at higher induction. In this paper, we examined the 2D vector magnetic properties excited by distorted flux density, which consists of the 1st (fundamental frequency: 50 Hz), 3rd, and 5th harmonics. Improved linear synthesis of the field intensity waveform (ILSFI) is proposed as a new estimation method of the field intensity, instead of the conventional linear synthesis of field intensity waveform (LSFI). The usefulness of the proposed ILSFI is demonstrated in the comparison with the measured results

  13. Measurement of 2D vector magnetic properties under the distorted flux density conditions

    Energy Technology Data Exchange (ETDEWEB)

    Urata, Shinya [Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, 700 Dannoharu, Oita 870-1192 (Japan)]. E-mail: urata@mag.eee.oita-u.ac.jp; Todaka, Takashi [Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, 700 Dannoharu, Oita 870-1192 (Japan); Enokizono, Masato [Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, 700 Dannoharu, Oita 870-1192 (Japan); Maeda, Yoshitaka [Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, 700 Dannoharu, Oita 870-1192 (Japan); Shimoji, Hiroyasu [Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, 700 Dannoharu, Oita 870-1192 (Japan)

    2006-09-15

    Under distorted flux density condition, it is very difficult to evaluate the field intensity, because there is no criterion for the measurement. In the linear approximation, the measured field intensity waveform (MFI) is compared with the linear synthesis of field intensity waveform (LSFI) in each frequency, and it is shown that they are not in good agreement at higher induction. In this paper, we examined the 2D vector magnetic properties excited by distorted flux density, which consists of the 1st (fundamental frequency: 50 Hz), 3rd, and 5th harmonics. Improved linear synthesis of the field intensity waveform (ILSFI) is proposed as a new estimation method of the field intensity, instead of the conventional linear synthesis of field intensity waveform (LSFI). The usefulness of the proposed ILSFI is demonstrated in the comparison with the measured results.

  14. Flux density measurements of radio sources at 2.14 millimeter wavelength

    International Nuclear Information System (INIS)

    Cogdell, J.R.; Davis, J.H.; Ulrich, B.T.; Wills, B.J.

    1975-01-01

    Flux densities of galactic and extragalactic sources, and planetary temperatures, have been measured at 2.14 mm wavelength (140 GHz). Results are presented for OJ 287; the galactic sources DR 21, W3, and Orion A; the extragalactic sources PKS 0106plus-or-minus01, 3C 84, 3C 120, BL Lac, 3C 216, 3C 273, 3C 279, and NGC 4151; and the Sun, Venus, Mars, and Jupiter. Also presented is the first measurement of the 2.14-mm temperature of Uranus. The spectra of some of these sources are discussed. The flux density scale was calibrated absolutely. The measurements were made with a new continuum receiver on the 4.88-m radio telescope of The University of Texas

  15. Field-aligned current density versus electric potential characteristics for magnetospheric flux tubes

    International Nuclear Information System (INIS)

    Lemaire, J.; Scherer, M.

    1983-01-01

    The field-aligned current density (Jsub(tot)) is a non-linear function of the applied potential difference (phi) between the ionosphere and the magnetosphere. This nonlinear function has been calculated for plasma boundary conditions typical in a dayside cusp magnetic flux tube. The J-characteristic of such a flux tube changes when the temperatures of the warm magnetospheric electrons and of the cold ionospheric electrons are modified; it changes also when the relative density of the warm plasma is modified; the presence of trapped secondary electrons changes also the J-characteristic. The partial currents contributed by the warm and cold electrons, and by warm and cold ions are illustrated. The dynamic characteristic of an electric circuit depends on the static characteristic of each component of the sytem: i.e. the resistive ionosphere, the return current region, and the region of particle precipitation whose field-aligned current/voltage characteristics have been studied in this article

  16. Installation for the study of heat transfer with high flux density

    International Nuclear Information System (INIS)

    Robin, M.; Schwab, B.

    1957-01-01

    As a result of their very low vapor pressure, metals with a low fusion point (sodium, sodium-potassium alloys, etc.) can be used at high temperature, as heating fluids, in installations whose internal pressure is close to atmospheric pressure. Owing to the very high convection coefficients which can be reached with these fluids and to the large temperature differences utilizable, it is possible to produce through the exchange surfaces considerable heat flux densities, of the order of those which exist through the canning of fuel elements in nuclear reactors. The installation described allowed a flux density of more than 200 W/cm 2 to be obtained, the heating fluid being a Na-K alloy (containing 56 per cent by weight of potassium) brought to a temperature around 550 deg. C. (author) [fr

  17. Precision flux density measurements of the giant planets at 8420 MHz

    Science.gov (United States)

    Turegano, J. A.; Klein, M. J.

    1981-01-01

    Precision measurements of the 3.56 cm flux densities of Jupiter, Saturn, Uranus, and Neptune are reported. The results are compared with previously published measurements as a means of: remotely sensing long-term changes in the microwave emission from the atmospheres of these planets and measuring the effects of Saturn's rings on the disk temperature as observed from earth at different ring inclination angles.

  18. Spatial and temporal variations in sap flux density in Japanese cedar (Cryptomeria japonica) trees, central Taiwan

    Science.gov (United States)

    Tseng, Han; Chiu, Chen-Wei; Wey, Tsong-Huei; Kume, Tomonori

    2013-04-01

    Sap flow measurement method is a technique widely used for measuring forest transpiration. However, variations in sap flow distribution can make accurately estimating individual tree-scale transpiration difficult. Significant spatial variations in sap flow across the sapwood within tree have been reported in many studies. In contrast, few studies have discussed azimuthal variations in sap flow, and even fewer have examined their seasonal change characteristics. This study was undertaken to clarify within-tree special and temporal variations in sap flow, and to propose an appropriate design for individual-tree scale transpiration estimates for Japanese cedar trees. The measurement was conducted in a Japanese cedar plantation located in Central Taiwan. Spatial distribution of sap flux density through the sapwood cross-section was measured using Granier's thermal dissipation technique. Sensors were installed at 1.3 m high on the east, west, north and south sides of the stem at 0-2 cm in 8 trees, and at 2-4 cm in the 6 larger trees. We found, in radial profile analysis, that sap flux densities measured at the depth of 2-4 cm were 50 % in average of those measured at depth of 0-2 cm. In azimuthal profile analysis, we found significant azimuthal variations in sap flux density. In one individual tree, the ratio of sap flux density on one aspect to another could be approximately 40-190 %, with no dependency on directions. Both radial and azimuthal profiles in most sample trees were fairly consistent throughout the measurement period. We concluded that radial and azimuthal variations in sap flow across sapwood might introduce significant errors in individual tree-scale transpiration estimations based on single point sap flow measurement, and seasonal change of within-tree spatial variations in sap flow could have insignificant impacts on accuracy of long-term individual tree-scale transpiration estimates. Keywords: transpiration, sap flow measurement, scaling up, sap flow

  19. Measurement of current density fluctuations and ambipolar particle flux due to magnetic fluctuations in MST

    International Nuclear Information System (INIS)

    Shen, Weimin.

    1992-08-01

    Studies of magnetic fluctuation induced particle transport on Reversed Field Pinch plasmas were done on the Madison Symmetric Torus. Plasma current density and current density fluctuations were measured using a multi-coil magnetic probes. The low frequency (f parallel B r >. The result of zero net charged particle loss was obtained, meaning the flux is ambipolar. The ambipolarity of low frequency global tearing modes is satisfied through the phase relations determined by tearing instabilities. The ambipolarity of high frequency localized modes could be partially explained by the simple model of Waltz based on the radial average of small scale turbulence

  20. Uncertainty and Sensitivity of Alternative Rn-222 Flux Density Models Used in Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Greg J. Shott, Vefa Yucel, Lloyd Desotell

    2007-06-01

    Performance assessments for the Area 5 Radioactive Waste Management Site on the Nevada Test Site have used three different mathematical models to estimate Rn-222 flux density. This study describes the performance, uncertainty, and sensitivity of the three models which include the U.S. Nuclear Regulatory Commission Regulatory Guide 3.64 analytical method and two numerical methods. The uncertainty of each model was determined by Monte Carlo simulation using Latin hypercube sampling. The global sensitivity was investigated using Morris one-at-time screening method, sample-based correlation and regression methods, the variance-based extended Fourier amplitude sensitivity test, and Sobol's sensitivity indices. The models were found to produce similar estimates of the mean and median flux density, but to have different uncertainties and sensitivities. When the Rn-222 effective diffusion coefficient was estimated using five different published predictive models, the radon flux density models were found to be most sensitive to the effective diffusion coefficient model selected, the emanation coefficient, and the radionuclide inventory. Using a site-specific measured effective diffusion coefficient significantly reduced the output uncertainty. When a site-specific effective-diffusion coefficient was used, the models were most sensitive to the emanation coefficient and the radionuclide inventory.

  1. Uncertainty and Sensitivity of Alternative Rn-222 Flux Density Models Used in Performance Assessment

    International Nuclear Information System (INIS)

    Greg J. Shott, Vefa Yucel, Lloyd Desotell Non-Nstec Authors: G. Pyles and Jon Carilli

    2007-01-01

    Performance assessments for the Area 5 Radioactive Waste Management Site on the Nevada Test Site have used three different mathematical models to estimate Rn-222 flux density. This study describes the performance, uncertainty, and sensitivity of the three models which include the U.S. Nuclear Regulatory Commission Regulatory Guide 3.64 analytical method and two numerical methods. The uncertainty of each model was determined by Monte Carlo simulation using Latin hypercube sampling. The global sensitivity was investigated using Morris one-at-time screening method, sample-based correlation and regression methods, the variance-based extended Fourier amplitude sensitivity test, and Sobol's sensitivity indices. The models were found to produce similar estimates of the mean and median flux density, but to have different uncertainties and sensitivities. When the Rn-222 effective diffusion coefficient was estimated using five different published predictive models, the radon flux density models were found to be most sensitive to the effective diffusion coefficient model selected, the emanation coefficient, and the radionuclide inventory. Using a site-specific measured effective diffusion coefficient significantly reduced the output uncertainty. When a site-specific effective-diffusion coefficient was used, the models were most sensitive to the emanation coefficient and the radionuclide inventory

  2. Anomalous B-H behaviour of electrical steels at very low flux density

    Energy Technology Data Exchange (ETDEWEB)

    Zurek, Stan [Wolfson Centre for Magnetics, School of Engineering, Cardiff University, Cardiff CF24 3AA (United Kingdom)], E-mail: ZurekS@cardiff.ac.uk; Al-Naemi, Faris; Moses, Anthony J.; Marketos, Philip [Wolfson Centre for Magnetics, School of Engineering, Cardiff University, Cardiff CF24 3AA (United Kingdom)

    2008-10-15

    The behaviour of ferromagnetic materials under very low magnetic field was investigated more than a century ago by Lord Rayleigh. However, it has been shown since that the so-called Rayleigh law fails for very low magnetic fields, although the explanation for this phenomenon was not given. An anomalous B-H behaviour at very low alternating peak flux density in conventional grain-oriented (GO) and non-oriented (NO) electrical steels is reported. It has been found that the initial permeability is constant for all the measured frequencies (from 20 to 400 Hz) at peak flux density below 0.1 mT, and in this region the magnetisation is almost reversible (for both GO and NO). At higher flux density the B-H loops become visibly irreversible, with a relatively narrow (for GO) or very wide (for NO) transition region. For GO the B-H loop becomes visibly 'distorted' for all frequencies at around 2 mT. The eddy current loss calculated from the so-called 'classical' equation gives values higher than the measured total losses at lower frequencies. Both these measured results are difficult to explain.

  3. The effects of variability on the number-flux-density relationship for radio sources

    International Nuclear Information System (INIS)

    Schuch, N.J.

    1981-01-01

    It has been known for some time that the number-flux-density relationship for radio sources requires a population of sources whose properties evolve with cosmological epoch, at least in models where the redshifts are all taken to be cosmological. In particular, the surveys made at metre wavelengths show, for bright sources, a slope of the log N -log S curve which is steeper than the value -1.5 expected in a static, non-evolving Euclidean universe. Here, N is the number of radio sources brighter than flux density S. Expansion without evolution in conventional geometrical models predicts slopes flatter than -1.5. If the radio survey is carried out at higher frequencies (typically 2.7 or 5 GHz - 11 or 6 cm wavelength), the slope of the log N -log S curve is steeper than -1.5 but not so steep as the slopes found for the low-frequency surveys. Many of the sources found in high-frequency surveys have radio spectra with relatively higher flux-densities in the centimetre range; these sources are frequently variable at high frequencies, with time-scales from a month or two upwards. Some possible effects of the variations on the observed counts of radio sources are considered. (author)

  4. Radiation budget, soil heat flux and latent heat flux at the forest floor in warm, temperate mixed forest

    International Nuclear Information System (INIS)

    Tamai, K.; Abe, T.; Araki, M.; Ito, H.

    1998-01-01

    Seasonal changes in the radiation budget and soil heat flux of a forest floor were measured in a mixed forest located in Kyoto, Japan. The basal area at breast height in the survey forest was about 15·82 m 2 ha −1 , for evergreen trees, and 12·46 m 2 ha −1 , for deciduous trees. The sky view factor was 16 and 22% at the survey site in the foliate and defoliate seasons, respectively. The small difference between the sky view factor in the two seasons was reflected in the seasonal change in the radiation budget of the forest floor. Namely, the net long-wave radiation changed rapidly in leafing and falling days, and the rate of net short-wave radiation was highest in April. The distinctive characteristic of the radiation budget was that the rates of available radiation in the daytime and at night were almost equal in September and October. Latent heat flux at the forest floor was estimated to be around 94 MJ m −2 annually, from our measurement with the simulation model. (author)

  5. Effects of high altitude clouds on the earth's infrared radiation flux

    Science.gov (United States)

    Wang, W.-C.; Kaplan, L. D.

    1983-01-01

    Attention is given to the results of a study of cirrus cloud properties which employed the Goddard Laboratory for Atmospheric Sciences' general circulation model and concentrated on the effects of the nonblackness of high clouds on the IR radiation flux. Although the thermal radiation flux is very sensitive to the treatment of cirrus optical properties in the IR, a more realistic assessment will depend on better parameterizations for cirrus cloud formation, persistence, and dissipation.

  6. Effect of mix proportion of high density concrete on compressive strength, density and radiation absorption

    International Nuclear Information System (INIS)

    Noor Azreen Masenwat; Mohamad Pauzi Ismail; Suhairy Sani; Ismail Mustapha; Nasharuddin Isa; Mohamad Haniza Mahmud; Mohammad Shahrizan Samsu

    2014-01-01

    To prevent radiation leaks at nuclear reactors, high-density concrete is used as an absorbent material for radiation from spreading into the environment. High-density concrete is a mixture of cement, sand, aggregate (usually high-density minerals) and water. In this research, hematite stone is used because of its mineral density higher than the granite used in conventional concrete mixing. Mix concrete in this study were divided into part 1 and part 2. In part 1, the concrete mixture is designed with the same ratio of 1: 2: 4 but differentiated in terms of water-cement ratio (0.60, 0.65, 0.70, 0.75, 0.80 ). Whereas, in part 2, the concrete mixture is designed to vary the ratio of 1: 1: 2, 1: 1.5: 3, 1: 2: 3, 1: 3: 6, 1: 2: 6 with water-cement ratio (0.7, 0.8, 0.85, 0.9). In each section, the division has also performed in a mixture of sand and fine sand hematite. Then, the physical characteristics of the density and the compressive strength of the mixture of part 1 and part 2 is measured. Comparisons were also made in terms of absorption of radiation by Cs-137 and Co-60 source for each mix. This paper describes and discusses the relationship between the concrete mixture ratio, the relationship with the water-cement ratio, compressive strength, density, different mixture of sand and fine sand hematite. (author)

  7. Spitzer Mid-to-Far-Infrared Flux Densities of Distant Galaxies

    Science.gov (United States)

    Papovich, Casey J.; Rudnick, G.; Le Floc'h, E.; van Dokkum, P. G.; Rieke, G. H.; Taylor, E. N.; Armus, L.; Gawiser, E.; Marcillac, D.; Huang, J.; Franx, M.

    2007-05-01

    We study the 24, 70, and 160 μm properties of high-redshift galaxies. Our primary interest is to improve the constraints on the total infrared (IR) luminosities, L(IR), of these galaxies. We combine Spitzer data in the southern Extended Chandra Deep Field with a Ks-band-selected galaxy sample with photometric redshifts from the Multiwavelength Survey by Yale-Chile. We used a stacking analysis to measure the average 70 and 160 μm flux densities of 1.5 250 μJy and 1.5 250 μJy have S(70)/S(24) flux ratios comparable to sources with X-ray detections or red rest-frame IR colors, suggesting that warm dust possibly heated by AGN produces high 24 μm emission. Based on the average 24-160 μm flux densities, 24 μm-selected galaxies at 1.5 rate observed in low redshift galaxies, suggesting that high redshift galaxies have star formation efficiencies and feedback processes comparable to lower redshift analogs. Support for this work was provided by NASA through the Spitzer Space Telescope Fellowship Program, through a contract issued by JPL, Caltech under a contract with NASA.

  8. Magnetic losses at high flux densities in nonoriented Fe-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Appino, C.; Fiorillo, F. [Istituto Nazionale di Ricerca Metrologica (INRIM), Torino (Italy); Ragusa, C. [Dipartimento di Ingegneria Elettrica, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy)], E-mail: carlo.ragusa@polito.it; Xie, B. [Dipartimento di Ingegneria Elettrica, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy)

    2008-10-15

    We present and discuss power loss measurements performed in Fe-(3.5 wt%)Si nonoriented laminations up to very high flux densities. The results are obtained on disk samples using a 1D/2D single-sheet tester, where the fieldmetric and the thermometric methods are applied upon overlapping polarization ranges. The power loss in the highest polarization regimes (e.g. J{sub p}>1.8 T) is measured, in particular, by the rate of rise of temperature method, both under controlled and uncontrolled flux density waveform, the latter case emulating the conditions met in practical unsophisticated experiments. Lack of control at such extreme J{sub p} levels is conducive to strong flux distortion, but the correspondingly measured loss figure can eventually be converted to the one pertaining to sinusoidal induction at the same J{sub p} values. This is demonstrated as a specific application of the statistical theory of magnetic losses, where the usual formulation for the energy losses in magnetic sheets under distorted induction is exploited in reverse fashion.

  9. Long-term Longitudinal Recurrences of the Open Magnetic Flux Density in the Heliosphere

    Energy Technology Data Exchange (ETDEWEB)

    Dósa, M.; Erdős, G., E-mail: dosa.melinda@wigner.mta.hu [Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1121 Budapest, Konkoly-Thege Miklós st 29-33 (Hungary)

    2017-04-01

    Open magnetic flux in the heliosphere is determined from the radial component of the magnetic field vector measured onboard interplanetary space probes. Previous Ulysses research has shown remarkable independence of the flux density from heliographic latitude, explained by super-radial expansion of plasma. Here we are investigating whether any longitudinal variation exists in the 50 year long OMNI magnetic data set. The heliographic longitude of origin of the plasma package was determined by applying a correction according to the solar wind travel time. Significant recurrent enhancements of the magnetic flux density were observed throughout solar cycle 23, lasting for several years. Similar, long-lasting recurring features were observed in the solar wind velocity, temperature and the deviation angle of the solar wind velocity vector from the radial direction. Each of the recurrent features has a recurrence period slightly differing from the Carrington rotation rate, although they show a common trend in time. Examining the coronal temperature data of ACE leads to the possible explanation that these long-term structures are caused by slow–fast solar wind interaction regions. A comparison with MESSENGER data measured at 0.5 au shows that these longitudinal magnetic modulations do not exist closer to the Sun, but are the result of propagation.

  10. Interpretation of a correlation between the flux densities of extended hard x-rays and microwave solar bursts

    International Nuclear Information System (INIS)

    Nelson, G.J.; Stewart, R.T.

    1979-01-01

    In a previous paper the authors showed that for extended bursts a good correlation exists between the observed 100 keV X-ray flux density and the 3.75 or 9.4 GHz microwave flux density. They now propose a source model for the extended bursts in which the microwave emission comes from thin shells at increasing heights for decreasing frequencies. This model with reasonable parameter values gives the observed microwave spectral characteristics and also explains why the X-ray and microwave flux densities are so well correlated

  11. An intercomparison and validation of satellite-based surface radiative energy flux estimates over the Arctic

    Science.gov (United States)

    Riihelä, Aku; Key, Jeffrey R.; Meirink, Jan Fokke; Kuipers Munneke, Peter; Palo, Timo; Karlsson, Karl-Göran

    2017-05-01

    Accurate determination of radiative energy fluxes over the Arctic is of crucial importance for understanding atmosphere-surface interactions, melt and refreezing cycles of the snow and ice cover, and the role of the Arctic in the global energy budget. Satellite-based estimates can provide comprehensive spatiotemporal coverage, but the accuracy and comparability of the existing data sets must be ascertained to facilitate their use. Here we compare radiative flux estimates from Clouds and the Earth's Radiant Energy System (CERES) Synoptic 1-degree (SYN1deg)/Energy Balanced and Filled, Global Energy and Water Cycle Experiment (GEWEX) surface energy budget, and our own experimental FluxNet / Satellite Application Facility on Climate Monitoring cLoud, Albedo and RAdiation (CLARA) data against in situ observations over Arctic sea ice and the Greenland Ice Sheet during summer of 2007. In general, CERES SYN1deg flux estimates agree best with in situ measurements, although with two particular limitations: (1) over sea ice the upwelling shortwave flux in CERES SYN1deg appears to be underestimated because of an underestimated surface albedo and (2) the CERES SYN1deg upwelling longwave flux over sea ice saturates during midsummer. The Advanced Very High Resolution Radiometer-based GEWEX and FluxNet-CLARA flux estimates generally show a larger range in retrieval errors relative to CERES, with contrasting tendencies relative to each other. The largest source of retrieval error in the FluxNet-CLARA downwelling shortwave flux is shown to be an overestimated cloud optical thickness. The results illustrate that satellite-based flux estimates over the Arctic are not yet homogeneous and that further efforts are necessary to investigate the differences in the surface and cloud properties which lead to disagreements in flux retrievals.

  12. Surface flux density distribution characteristics of bulk high-T{sub c} superconductor in external magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Torii, S.; Yuasa, K

    2004-10-01

    Various magnetic levitation systems using oxide superconductors are developed as strong pinning forces are obtained in melt-processed bulk. However, the trapped flux of superconductor is moved by flux creep and fluctuating magnetic field. Therefore, to examine the internal condition of superconductor, the authors measure the dynamic surface flux density distribution of YBCO bulk. Flux density measurement system has a structure with the air-core coil and the Hall sensors. Ten Hall sensors are arranged in series. The YBCO bulk, which has 25 mm diameter and 13 mm thickness, is field cooled by liquid nitrogen. After that, magnetic field is changed by the air-core coil. This paper describes about the measured results of flux density distribution of YBCO bulk in the various frequencies of air-core coils currents.

  13. Calculation of the magnetic flux density distribution in type-II superconductors with finite thickness and well-defined geometry

    International Nuclear Information System (INIS)

    Forkl, A.; Kronmueller, H.

    1995-01-01

    The distribution of the critical current density j c (r) in hard type-II superconductors depends strongly on their sample geometry. Rules are given for the construction of j c (r). Samples with homogeneous thickness are divided into cakelike regions with a unique current direction. The spatial magnetic flux density distribution and the magnetic polarization of such a cakelike unit cell with homogeneous current density are calculated analytically. The magnetic polarization and magnetic flux density distribution of a superconductor in the mixed state is then given by an adequate superposition of the unit cell solutions. The theoretical results show good agreement with magneto-optically determined magnetic flux density distributions of a quadratic thin superconducting YBa 2 Cu 3 O 7-x film. The current density distribution is discussed for several sample geometries

  14. A reference system for the measurement of low-strength magnetic flux density

    International Nuclear Information System (INIS)

    Fiorillo, F.; Durin, G.F.; Rocchino, L.

    2006-01-01

    Magnetic flux density standards traceable to the SI units have been developed at IEN-INRIM, by which dissemination for general measurement and testing activities can be pursued. The reference system covers a range of values extending from μ 0 H∼1T to μ 0 H∼10μT and is centered on the use of NMR magnetometers, calibrated coils, and stable current sources. The relative measuring uncertainty of the system is shown to increases with decreasing the field strength value and it is estimated to range between a few 10 -6 and some 10 -3

  15. The determination of self-powered neutron detector sensitivity on thermal and epithermal neutron flux densities

    International Nuclear Information System (INIS)

    Erben, O.

    1980-01-01

    The coefficients of thermal and epithermal neutron flux density depression and self-shielding for the SPN detectors with vanadium, rhodium, silver and cobalt emitters are presented, (for cobalt SPN detectors the functions describing the absorbtion of neutrons along the emitter cross-section are also shown). Using these coefficients and previously published beta particle escape efficiencies, sensitivities are determined for the principal types of detectors produced by Les Cables de Lyon and SODERN companies. The experiments and their results verifying the validity of the theoretical work are described. (author)

  16. The radiation budget of stratocumulus clouds measured by tethered balloon instrumentation: Variability of flux measurements

    Science.gov (United States)

    Duda, David P.; Stephens, Graeme L.; Cox, Stephen K.

    1990-01-01

    Measurements of longwave and shortwave radiation were made using an instrument package on the NASA tethered balloon during the FIRE Marine Stratocumulus experiment. Radiation data from two pairs of pyranometers were used to obtain vertical profiles of the near-infrared and total solar fluxes through the boundary layer, while a pair of pyrgeometers supplied measurements of the longwave fluxes in the cloud layer. The radiation observations were analyzed to determine heating rates and to measure the radiative energy budget inside the stratocumulus clouds during several tethered balloon flights. The radiation fields in the cloud layer were also simulated by a two-stream radiative transfer model, which used cloud optical properties derived from microphysical measurements and Mie scattering theory.

  17. Density determination of railroad ballast by means of gamma radiation

    International Nuclear Information System (INIS)

    Mundt, M.

    1983-01-01

    Proceeding from the requirements of a measuring method for determining the degrees of densification and of soiling of railroad beds, conclusions are drawn for the use of a radiometric technique, considering measuring geometry, radiation energy, and instrumentation. Results obtained from laboratory experiments with a ballast pressure unit are presented. It is pointed out that the application of radiometric density measurements has to be linked with investigations of the behaviour of the rock species used, in order to obtain a valid interpretation of the measured density with regard to the properties and the composition of the railroad bed. (author)

  18. Effect of magnetic flux-densities of up to 0.1 Tesla on copper electrodeposition

    International Nuclear Information System (INIS)

    Cifuentes, L.; Artigas, M.; Riveros, G.; Warczok, A.

    2003-01-01

    The effect of magnetic flux densities (B) between 0.0 and 0.1 Tesla on cathode and anode over potentials, cell voltage and electro deposit quality was determined fro a lab-scale copper electrowinning cell which operates at industrial current, density values. Cell voltage decreases with increasing B. The cathodic overpotential decreases by 30% when B increases from 0.0 to 0.1 T. The anodic overpotential also decreases with increasing B, but this effect is six times less than the corresponding effect on the cathodic overpotential. Cathodic effects can be predicted by an expression derived from electrochemical kinetics and magnetohydrodynamic theory. Anodic effects cannot be predicted in the same way. The size of grains and intergranular voids decreases and the surface of the electro deposit becomes smoother as B increases, which means that, in the studied conditions, the quality of the produced copper deposits improves. (Author) 26 refs

  19. Potential effects of ultraviolet radiation reduction on tundra nitrous oxide and methane fluxes in maritime Antarctica.

    Science.gov (United States)

    Bao, Tao; Zhu, Renbin; Wang, Pei; Ye, Wenjuan; Ma, Dawei; Xu, Hua

    2018-02-27

    Stratospheric ozone has begun to recover in Antarctica since the implementation of the Montreal Protocol. However, the effects of ultraviolet (UV) radiation on tundra greenhouse gas fluxes are rarely reported for Polar Regions. In the present study, tundra N 2 O and CH 4 fluxes were measured under the simulated reduction of UV radiation in maritime Antarctica over the last three-year summers. Significantly enhanced N 2 O and CH 4 emissions occurred at tundra sites under the simulated reduction of UV radiation. Compared with the ambient normal UV level, a 20% reduction in UV radiation increased tundra emissions by an average of 8 μg N 2 O m -2 h -1 and 93 μg CH 4 m -2 h -1 , whereas a 50% reduction in UV radiation increased their emissions by an average of 17 μg N 2 O m -2 h -1 and 128 μg CH 4 m -2 h -1 . No statistically significant correlation (P > 0.05) was found between N 2 O and CH 4 fluxes and soil temperature, soil moisture, total carbon, total nitrogen, NO 3 - -N and NH 4 + -N contents. Our results confirmed that UV radiation intensity is an important factor affecting tundra N 2 O and CH 4 fluxes in maritime Antarctica. Exclusion of the effects of reduced UV radiation might underestimate their budgets in Polar Regions with the recovery of stratospheric ozone.

  20. Density measurement using gamma radiation - theory and application

    International Nuclear Information System (INIS)

    Springer, E.K.

    1979-01-01

    There are still widespread uncertainties about the use and safety of gamma radiation in industries. This paper describes, by the example of radiometric density measurement, the theory of gamma radiation. The differences and advantages of both types of detectors, the ionization chamber and the scintillation counter, are discussed. The degree of accuracy which can be expected from the radiometric density meter will be defined, and the inter-relationship: source strength - measuring range - measuring length(normally the pipe diameter) in relation to the measuring accuracy required will be explained in detail. The use of radioactive material requires the permission of the Atomic Energy Board. The formalities involved to receive a user's licence and the implementations of safety standards set by the local authorities are discussed in depth [af

  1. A new method for simultaneous measurement of convective and radiative heat flux in car underhood applications

    International Nuclear Information System (INIS)

    Khaled, M; Garnier, B; Peerhossaini, H; Harambat, F

    2010-01-01

    A new experimental technique is presented that allows simultaneous measurement of convective and radiative heat flux in the underhood. The goal is to devise an easily implemented and accurate experimental method for application in the vehicle underhood compartment. The new method is based on a technique for heat-flux measurement developed by the authors (Heat flow (flux) sensors for measurement of convection, conduction and radiation heat flow 27036-2, © Rhopoint Components Ltd, Hurst Green, Oxted, RH8 9AX, UK) that uses several thermocouples in the thickness of a thermal resistive layer (foil heat-flux sensor). The method proposed here uses a pair of these thermocouples with different radiative properties. Measurements validating this novel technique are carried out on a flat plate with a prescribed constant temperature in both natural- and forced-convection flow regimes. The test flat plate is instrumented by this new technique, and also with a different technique that is intrusive but very accurate, used as reference here (Bardon J P and Jarny Y 1994 Procédé et dispositif de mesure transitoire de température et flux surfacique Brevet n°94.011996, 22 February). Discrepancies between the measurements by the two techniques are less than 10% for both convective and radiative heat flux. Error identification and sensitivity analysis of the new method are also presented

  2. Design and Construction of a Radiation Source of Extreme Flux

    OpenAIRE

    Valle Brozas, Francisco

    2017-01-01

    [EN]The present thesis consists of the design and construction of an X-ray source through the interaction of an ultra-intense laser with a solid and/or liquid target. Specifically, the laser technology suitable for this purpose has been investigated, the characteristics of the laser-matter interaction have been studied and possible applications of the generated X-radiation (and accelerated electrons) have been explored. Nowadays, the development of sources of ionizing radiation through la...

  3. Lognormal Kalman filter for assimilating phase space density data in the radiation belts

    Science.gov (United States)

    Kondrashov, D.; Ghil, M.; Shprits, Y.

    2011-11-01

    Data assimilation combines a physical model with sparse observations and has become an increasingly important tool for scientists and engineers in the design, operation, and use of satellites and other high-technology systems in the near-Earth space environment. Of particular importance is predicting fluxes of high-energy particles in the Van Allen radiation belts, since these fluxes can damage spaceborne platforms and instruments during strong geomagnetic storms. In transiting from a research setting to operational prediction of these fluxes, improved data assimilation is of the essence. The present study is motivated by the fact that phase space densities (PSDs) of high-energy electrons in the outer radiation belt—both simulated and observed—are subject to spatiotemporal variations that span several orders of magnitude. Standard data assimilation methods that are based on least squares minimization of normally distributed errors may not be adequate for handling the range of these variations. We propose herein a modification of Kalman filtering that uses a log-transformed, one-dimensional radial diffusion model for the PSDs and includes parameterized losses. The proposed methodology is first verified on model-simulated, synthetic data and then applied to actual satellite measurements. When the model errors are sufficiently smaller then observational errors, our methodology can significantly improve analysis and prediction skill for the PSDs compared to those of the standard Kalman filter formulation. This improvement is documented by monitoring the variance of the innovation sequence.

  4. Sapflow+: a four-needle heat-pulse sap flow sensor enabling nonempirical sap flux density and water content measurements.

    Science.gov (United States)

    Vandegehuchte, Maurits W; Steppe, Kathy

    2012-10-01

    • To our knowledge, to date, no nonempirical method exists to measure reverse, low or high sap flux density. Moreover, existing sap flow methods require destructive wood core measurements to determine sapwood water content, necessary to convert heat velocity to sap flux density, not only damaging the tree, but also neglecting seasonal variability in sapwood water content. • Here, we present a nonempirical heat-pulse-based method and coupled sensor which measure temperature changes around a linear heater in both axial and tangential directions after application of a heat pulse. By fitting the correct heat conduction-convection equation to the measured temperature profiles, the heat velocity and water content of the sapwood can be determined. • An identifiability analysis and validation tests on artificial and real stem segments of European beech (Fagus sylvatica L.) confirm the applicability of the method, leading to accurate determinations of heat velocity, water content and hence sap flux density. • The proposed method enables sap flux density measurements to be made across the entire natural occurring sap flux density range of woody plants. Moreover, the water content during low flows can be determined accurately, enabling a correct conversion from heat velocity to sap flux density without destructive core measurements. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  5. The Pressure and Magnetic Flux Density Analysis of Helical-Type DC Electromagnetic Pump

    International Nuclear Information System (INIS)

    Lee, Geun Hyeong; Kim, Hee Reyoung

    2016-01-01

    The developed pressure was made by only electromagnetic force eliminating probability of impurities contact, therefore the high reactivity materials such as alkali were best match to electromagnetic pump. The heavy ion accelerator facility by Rare Isotope Science Project (RISP) in Korea is trying to construct accelerator using liquid lithium for high efficiency of acceleration by decreasing charge state. The helical-type DC electromagnetic pump was employed to make a charge stripper that decrease charge state of heavy ion. The specification of electromagnetic pump was developed pressure of 15 bar with flowrate of 6 cc/s in the condition of 200℃. The pressure of DC electromagnetic pump was analyzed in the aspects of current and number of duct turns. The developed pressure was almost proportional to input current because relatively low flowrate made negligible of the electromotive force and hydraulic pressure drop. The pressure and magnetic flux density of helical-type DC electromagnetic pump were analyzed. The pressure was proportion to input current and number of duct turns, and magnetic flux density was higher when ferromagnet was applied at electromagnetic pump. It seems that number of duct turns could be increase and ferromagnet could be applied in order to increase pressure of DC electromagnetic pump with constant input current

  6. Experimental study of the critical density of heat flux in open channels cooled with helium - II

    International Nuclear Information System (INIS)

    Pron'ko, V.G.; Gorokhov, V.V.; Saverin, V.N.

    1981-01-01

    Experimental values of the critical density of a heat flux qsub(cr) in uniformly heated open channels cooled with helium-2 are reported for the first time. The experimental test bench and experimental element are described. Experimental data are obtained in cylindrical channels of 12Kh18N1OT steel with inner diameter d=0.8, 1.8; 2.8 mm and ratio l/d=20.8, 44, 85. The channel orientation has varied from vertical to horizontal position, the immersion depth - from 100, to 600 mm. It has been found that the heat transfer crisis propagation over the whole length of the channel with He-2 occurs practically instantaneously. The qsub(cr) value depends essentially on the bath liquid temperature, angle of inclivnation and relative length (l/d) of the channel with qsub(cr) approximately (l/d)sup(-1.5) being independent of the depth of channel immersion. The obtained values of critical density of a heat flux in channels are papproximately by an order less than those found for a great bulk of He-2. The results presented may be used for designing various types of devices cooled with He-2 and development of heat exchange theory in it [ru

  7. Post radiation grafting of vinyl acetate onto low density polyethylene films: preparation and properties of membrane

    International Nuclear Information System (INIS)

    Dessouki, A.M.

    1987-01-01

    Reverse osmosis membranes were prepared by the post radiation grafting of vinyl acetate onto low density polyethylene films. The factors affecting the grafting process such as radiation dose, monomer concentration and temperature on the grafting yield were studied. It was found that the dependence of the grafting rate on radiation intensity and monomer concentration was found to be of 0.64 and 1.4 order, respectively. The activation energy for this grafting system was calculated and found to be 4.45 kcal/mol above 30 0 C. Some properties of the grafted films such as specific electric resistance, water uptake, mechanical properties and thermal and chemical stability were investigated. An improvement in these properties was observed which makes possible the use of these membranes in some practical applications. The use of such membranes for reverse osmosis desalination of saline water was tested. The effect of operating time, degree of grafting and applied pressure on the water flux and salt rejection were determined. The results showed salt rejection percent over 90% and a reasonable water flux. A suitable degree of grafting of the membrane was determined as well as the optimum applied pressure. (author)

  8. Evaluating Surface Radiation Fluxes Observed From Satellites in the Southeastern Pacific Ocean

    Science.gov (United States)

    Pinker, R. T.; Zhang, B.; Weller, R. A.; Chen, W.

    2018-03-01

    This study is focused on evaluation of current satellite and reanalysis estimates of surface radiative fluxes in a climatically important region. It uses unique observations from the STRATUS Ocean Reference Station buoy in a region of persistent marine stratus clouds 1,500 km off northern Chile during 2000-2012. The study shows that current satellite estimates are in better agreement with buoy observations than model outputs at a daily time scale and that satellite data depict well the observed annual cycle in both shortwave and longwave surface radiative fluxes. Also, buoy and satellite estimates do not show any significant trend over the period of overlap or any interannual variability. This verifies the stability and reliability of the satellite data and should make them useful to examine El Niño-Southern Oscillation variability influences on surface radiative fluxes at the STRATUS site for longer periods for which satellite record is available.

  9. Combined conduction and radiation in a two-layer planar medium with flux boundary condition

    International Nuclear Information System (INIS)

    Ho, C.H.; Ozisik, M.N.

    1987-01-01

    The interaction of conduction and radiation is investigated under both transient and steady-state conditions for an absorbing, emitting, and isotropically scattering two-layer slab having opaque coverings at both boundaries. The slab is subjected to an externally applied constant heat flux at one boundary surface and dissipates heat by radiation into external ambients from both boundary surfaces. An analytic approach is applied to solve the radiation part of the problem, and a finite-difference scheme is used to solve the conduction part. The effects of the conduction-to-radiation parameter, the single scattering albedo, the optical thickness, and the surface emissivity on the temperature distribution are examined

  10. Ecosystem carbon and radiative fluxes: a global synthesis based on the FLUXNET network.

    Science.gov (United States)

    Cescatti, A.

    2009-04-01

    Solar radiation is the most important environmental factor driving the temporal and spatial variability of the gross primary productivity (GPP) in terrestrial ecosystems. At the ecosystem scale, the light use efficiency (LUE) depends not only on radiation quantity but also on radiation "quality" both in terms of spectral composition and angular distribution. The day-to-day variations in LUE are largely determined by changes in the ratio of diffuse to total radiation. The relative importance of the concurrent variation in total incoming radiation and in LUE is essential to estimate the sign and the magnitude of the GPP sensitivity to radiation. Despite the scientific relevance of this issue, a global assessment on the sensitivity of GPP to the variations of Phar is still missing. Such an analysis is needed to improve our understanding of the current and future impacts of aerosols and cloud cover on the spatio-temporal variability of GPP. The current availability of ecosystem carbon fluxes, together with separate measurements of incoming direct and diffuse Phar at a large number of flux sites, offers the unique opportunity to extend the previous investigation, both in terms of ecosystem, spatial and climate coverage, and to address questions about the internal (e.g. leaf area index, canopy structure) and external (e.g. cloudiness, covarying meteorology) factors affecting the ecosystem sensitivity to radiation geometry. For this purpose half-hourly measurements of carbon fluxes and radiation have been analyzed at about 220 flux sites for a total of about 660 site-years. This analysis demonstrates that the sensitivity of GPP to incoming radiation varies across the different plant functional types and is correlated with the leaf area index and the local climatology. In particular, the sensitivity of GPP to changes in incoming diffuse light maximizes for the broadleaved forests of the Northern Hemisphere.

  11. Influence of crystal shapes on radiative fluxes in visible wavelength: ice crystals randomly oriented in space

    Directory of Open Access Journals (Sweden)

    P. Chervet

    1996-08-01

    Full Text Available Radiative properties of cirrus clouds are one of the major unsolved problems in climate studies and global radiation budget. These clouds are generally composed of various ice-crystal shapes, so we tried to evaluate effects of the ice-crystal shape on radiative fluxes. We calculated radiative fluxes of cirrus clouds with a constant geometrical depth, composed of ice crystals with different shapes (hexagonal columns, bullets, bullet-rosettes, sizes and various concentrations. We considered ice particles randomly oriented in space (3D case and their scattering phase functions were calculated by a ray-tracing method. We calculated radiative fluxes for cirrus layers for different microphysical characteristics by using a discrete-ordinate radiative code. Results showed that the foremost effect of the ice-crystal shape on radiative properties of cirrus clouds was that on the optical thickness, while the variation of the scattering phase function with the ice shape remained less than 3% for our computations. The ice-water content may be a better choice to parameterize the optical properties of cirrus, but the shape effect must be included.

  12. Flux

    DEFF Research Database (Denmark)

    Ravn, Ib

    . FLUX betegner en flyden eller strømmen, dvs. dynamik. Forstår man livet som proces og udvikling i stedet for som ting og mekanik, får man et andet billede af det gode liv end det, som den velkendte vestlige mekanicisme lægger op til. Dynamisk forstået indebærer det gode liv den bedst mulige...... kanalisering af den flux eller energi, der strømmer igennem os og giver sig til kende i vore daglige aktiviteter. Skal vores tanker, handlinger, arbejde, samvær og politiske liv organiseres efter stramme og faste regelsæt, uden slinger i valsen? Eller skal de tværtimod forløbe ganske uhindret af regler og bånd...

  13. A study of influence of material properties on magnetic flux density induced in magneto rheological damper through finite element analysis

    Directory of Open Access Journals (Sweden)

    Gurubasavaraju T. M.

    2018-01-01

    Full Text Available Magnetorheological fluids are smart materials, which are responsive to the external stimulus and changes their rheological properties. The damper performance (damping force is dependent on the magnetic flux density induced at the annular gap. Magnetic flux density developed at fluid flow gap of MR damper due to external applied current is also dependent on materials properties of components of MR damper (such as piston head, outer cylinder and piston rod. The present paper discus about the influence of different materials selected for components of the MR damper on magnetic effect using magnetostatic analysis. Different materials such as magnetic and low carbon steels are considered for piston head of the MR damper and magnetic flux density induced at fluid flow gap (filled with MR fluid is computed for different DC current applied to the electromagnetic coil. Developed magnetic flux is used for calculating the damper force using analytical method for each case. The low carbon steel has higher magnetic permeability hence maximum magnetic flux could pass through the piston head, which leads to higher value of magnetic effect induction at the annular gap. From the analysis results it is observed that the magnetic steel and low carbon steel piston head provided maximum magnetic flux density. Eventually the higher damping force can be observed for same case.

  14. A simulation model of distributions of radiational flux at leaf surfaces in crowns of fruit trees

    International Nuclear Information System (INIS)

    Yamamoto, T.

    1988-01-01

    A computer-model was constructed for estimating distributions with time of radiational fluxes at leaf surfaces throughout fruit tree canopies in which leaves did not distribute uniformely in three dimensional space. Several assumptions were set up to construct the model for approximation of using solid geometry. For irregular distribution of leaf area in three dimensional space data were used in the simulation as number of leaves per internal cubic bloc of a cubic grid (n-divided per side). Several main parameters used were peculiar to fruit species which contain parameters (λ, ν) of Beta function to calculate both probability density function of leaf area distribution with respect to inclination angle and leaf extinction coefficient for parallel beam by leaves parameters (A, R i ) to calculate stem extinction coefficient for parallel beam, and parameters (D i ) to calculate leaf extinction coefficient of downward transmission and downward reflection. With these data and parameters solid geometry and Lambert-Beer's law constituted this model

  15. The Eddington approximation calculation of radiation flux in the atmosphere–ocean system

    International Nuclear Information System (INIS)

    Shi, Chong; Nakajima, Teruyuki

    2015-01-01

    An analytical approximation method is presented to calculate the radiation flux in the atmosphere–ocean system using the Eddington approximation when the upwelling radiation from the ocean body is negligibly small. Numerical experiments were carried out to investigate the feasibility of the method in two cases: flat and rough ocean surfaces. The results show good consistency for the reflectivity at the top of atmosphere and transmissivity just above the ocean surface, in comparison with the exact values calculated by radiative transfer models in each case. Moreover, an obvious error might be introduced for the calculation of radiation flux at larger solar zenith angles when the roughness of the ocean surface is neglected. - Highlights: • The Eddington approximation method is extended to the atmosphere–ocean system. • The roughness of ocean surface cannot be neglected at lager solar zenith angles. • Unidirectional reflectivity for rough ocean surface is proposed

  16. Examinations for the determination of the flux density of sputtered iron using laser induced fluorescence

    International Nuclear Information System (INIS)

    Schweer, H.B.

    1983-11-01

    In this work investigations are described to measure the flux density of sputtered iron atoms by means of laser induced fluorescence. In a laboratory experiment an iron target (stainless steel 316, Inconel 600), was bombarded with 10 keV Ar + and 2.5 keV H + and the population distribution of the energy levels of the ground state a 5 D and the metastable state a 5 F was measured. In the plasma wall region in the ISX-B tokamak at the Oak Ridge National Laboratory (USA) neutral iron atoms were measured the first time by laser induced fluorescence. A detection limit of 10 6 atoms/cm 3 was found and sputtered iron atoms were observed in the first 15 ms of the discharge. (orig./BRB)

  17. Design of PCB search coils for AC magnetic flux density measurement

    Science.gov (United States)

    Ulvr, Michal

    2018-04-01

    This paper presents single-layer, double-layer and ten-layer planar square search coils designed for AC magnetic flux density amplitude measurement up to 1 T in the low frequency range in a 10 mm air gap. The printed-circuit-board (PCB) method was used for producing the search coils. Special attention is given to a full characterization of the PCB search coils including a comparison between the detailed analytical design method and the finite integration technique method (FIT) on the one hand, and experimental results on the other. The results show very good agreement in the resistance, inductance and search coil constant values (the area turns) and also in the frequency dependence of the search coil constant.

  18. Density profiles and particle fluxes of heavy impurities in the limiter shadow region of a tokamak

    International Nuclear Information System (INIS)

    Claassen, H.A.; Repp, H.

    1980-01-01

    For the case of low impurity concentration, transport calculations have been performed for heavy impurities, in the scrape-off layer plasma of a tokamak with a poloidal ring limiter. The theory is based on the drift-kinetic equations for the various ionization states of the impurity ions taking due consideration of the convection and collision processes. The background plasma and the impurity sources from the torus wall and the limiter surface enter the theory as input parameters. The theory is developed for the first two orders of the drift approximation. Numerical results are given to zero order drift approximation for the radial profiles of density and particle fluxes parallel to the magnetic field. (orig.)

  19. Effect of stable-density stratification on counter gradient flux of a homogeneous shear flow

    Energy Technology Data Exchange (ETDEWEB)

    Lida, Oaki; Nagano, Yasutaka [Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya (Japan). Department of Mechanical Engineering

    2007-01-15

    We performed direct numerical simulations of homogeneous shear flow under stable-density stratification to study the buoyancy effects on the heat and momentum transfer. These numerical data were compared with those of a turbulent channel flow to investigate the similarity between the near-wall turbulence and the homogeneous shear flow. We also investigated the generation mechanism of the persistent CGFs (counter gradient fluxes) appearing at the higher wavenumbers of the cospectrum, and lasting over a long time without oscillation. Spatially, the persistent CGFs are associated with the longitudinal vortical structure, which is elongated in the streamwise direction and typically observed in both homogeneous shear flow and near-wall turbulence. The CGFs appear at both the top and bottom of this longitudinal vortical structure, and expand horizontally with an increase in the Richardson number. It was found that the production and turbulent-diffusion terms are responsible for the distribution of the Reynolds shear stress including the persistent CGFs. The buoyancy term, combined with the swirling motion of the vortex, contributes to expand the persistent CGF regions and decrease the down gradient fluxes. (author)

  20. The influence of land surface parameters on energy flux densities derived from remote sensing data

    Energy Technology Data Exchange (ETDEWEB)

    Tittebrand, A.; Schwiebus, A. [Inst. for Hydrology und Meteorology, TU Dresden (Germany); Berger, F.H. [Observatory Lindenberg, German Weather Service, Lindenberg (Germany)

    2005-04-01

    Knowledge of the vegetation properties surface reflectance, normalised difference vegetation index (NDVI) and leaf area index (LAI) are essential for the determination of the heat and water fluxes between terrestrial ecosystems and the atmosphere. Remote sensing data can be used to derive spatial estimates of the required surface properties. The determination of land surface parameters and their influence on radiant and energy flux densities is investigated with data of different remote sensing systems. Sensitivity studies show the importance of correctly derived land surface properties to estimate the key quantity of the hydrological cycle, the evapotranspiration (L.E), most exactly. In addition to variable parameters like LAI or NDVI there are also parameters which are can not be inferred from satellite data but needed for the Penman-Monteith approach. Fixed values are assumed for these variables because they have little influence on L.E. Data of Landsat-7 ETM+ and NOAA-16 AVHRR are used to show results in different spatial resolution. The satellite derived results are compared with ground truth data provided by the Observatory Lindenberg of the German Weather Service. (orig.)

  1. Intermittent electron density and temperature fluctuations and associated fluxes in the Alcator C-Mod scrape-off layer

    Science.gov (United States)

    Kube, R.; Garcia, O. E.; Theodorsen, A.; Brunner, D.; Kuang, A. Q.; LaBombard, B.; Terry, J. L.

    2018-06-01

    The Alcator C-Mod mirror Langmuir probe system has been used to sample data time series of fluctuating plasma parameters in the outboard mid-plane far scrape-off layer. We present a statistical analysis of one second long time series of electron density, temperature, radial electric drift velocity and the corresponding particle and electron heat fluxes. These are sampled during stationary plasma conditions in an ohmically heated, lower single null diverted discharge. The electron density and temperature are strongly correlated and feature fluctuation statistics similar to the ion saturation current. Both electron density and temperature time series are dominated by intermittent, large-amplitude burst with an exponential distribution of both burst amplitudes and waiting times between them. The characteristic time scale of the large-amplitude bursts is approximately 15 μ {{s}}. Large-amplitude velocity fluctuations feature a slightly faster characteristic time scale and appear at a faster rate than electron density and temperature fluctuations. Describing these time series as a superposition of uncorrelated exponential pulses, we find that probability distribution functions, power spectral densities as well as auto-correlation functions of the data time series agree well with predictions from the stochastic model. The electron particle and heat fluxes present large-amplitude fluctuations. For this low-density plasma, the radial electron heat flux is dominated by convection, that is, correlations of fluctuations in the electron density and radial velocity. Hot and dense blobs contribute only a minute fraction of the total fluctuation driven heat flux.

  2. High-resolution Tangential AXUV Arrays for Radiated Power Density Measurements on NSTX-U

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Aparicio, L [PPPL; Bell, R E [PPPL; Faust, I [MIT; Tritz, K [The Johns Hopkins University, Baltimore, MD, 21209, USA; Diallo, A [PPPL; Gerhardt, S P [PPPL; Kozub, T A [PPPL; LeBlanc, B P [PPPL; Stratton, B C [PPPL

    2014-07-01

    Precise measurements of the local radiated power density and total radiated power are a matter of the uttermost importance for understanding the onset of impurity-induced instabilities and the study of particle and heat transport. Accounting of power balance is also needed for the understanding the physics of various divertor con gurations for present and future high-power fusion devices. Poloidal asymmetries in the impurity density can result from high Mach numbers and can impact the assessment of their flux-surface-average and hence vary the estimates of P[sub]rad (r, t) and (Z[sub]eff); the latter is used in the calculation of the neoclassical conductivity and the interpretation of non-inductive and inductive current fractions. To this end, the bolometric diagnostic in NSTX-U will be upgraded, enhancing the midplane coverage and radial resolution with two tangential views, and adding a new set of poloidally-viewing arrays to measure the 2D radiation distribution. These systems are designed to contribute to the near- and long-term highest priority research goals for NSTX-U which will integrate non-inductive operation at reduced collisionality, with high-pressure, long energy-confinement-times and a divertor solution with metal walls.

  3. Radiative flux emitted by a burning PMMA slab

    International Nuclear Information System (INIS)

    Parent, G; Acem, Z; Collin, A; Berfroi, R; Boulet, P; Pizzo, Y; Mindykowski, P; Kaiss, A; Porterie, B

    2012-01-01

    The degradation of a PMMA sample has been studied based on experimental results obtained for the radiation emission by a burning slab. Observations of the infrared emission perpendicular to the plate, in the range where the optically thin flame is weakly emitting, indicate a plate temperature close to 680 K which is an indication on the surface temperature during the degradation process. Observations from the side allow a flame characterization without the plate emission superimposition. This is a promising way for evaluating data regarding the flame characteristics: temperature, gaz concentration and soot volumetric fraction.

  4. Collision density approach of radiation damage in a multispecies medium

    International Nuclear Information System (INIS)

    Lux, I.; Pazsit, I.

    1981-01-01

    Space-energy dependent forward type equations for the collision densities of energetic atoms in a multispecies semi-infinite homogeneous medium are formulated. Introduction of the one-dimensional isotropic forward-backward model of Fermi for the scattering and application of the Laplace transform with respect to the lethargy variable will lead to a linear differential equation system with constant coefficients. This equation system is solved for an arbitrary number of species and relations between the collision densities and defect distributions of the different species are given in the Kinchin-Pease model of radiation damage. The case of an alien particle incident on a two-component target is examined in some detail and the sputtering spectra for the three species are given numerically. (author)

  5. Collision density approach of radiation damage in a multispecies medium

    Energy Technology Data Exchange (ETDEWEB)

    Lux, I; Pazsit, I [Koezponti Elelmiszeripari Kutato Intezet, Budapest (Hungary)

    1981-01-01

    Space-energy dependent forward type equations for the collision densities of energetic atoms in a multispecies semi-infinite homogeneous medium are formulated. Introduction of the one-dimensional isotropic forward-backward model of Fermi for the scattering and application of the Laplace transform with respect to the lethargy variable will lead to a linear differential equation system with constant coefficients. This equation system is solved for an arbitrary number of species and relations between the collision densities and defect distributions of the different species are given in the Kinchin-Pease model of radiation damage. The case of an alien particle incident on a two-component target is examined in some detail and the sputtering spectra for the three species are given numerically.

  6. Propagation of a cylindrical shock wave in a rotating dusty gas with heat conduction and radiation heat flux

    International Nuclear Information System (INIS)

    Vishwakarma, J P; Nath, G

    2010-01-01

    A self-similar solution for the propagation of a cylindrical shock wave in a dusty gas with heat conduction and radiation heat flux, which is rotating about the axis of symmetry, is investigated. The shock is assumed to be driven out by a piston (an inner expanding surface) and the dusty gas is assumed to be a mixture of non-ideal gas and small solid particles. The density of the ambient medium is assumed to be constant. The heat conduction is expressed in terms of Fourier's law and radiation is considered to be of diffusion type for an optically thick grey gas model. The thermal conductivity K and the absorption coefficient α R are assumed to vary with temperature and density. Similarity solutions are obtained, and the effects of variation of the parameter of non-idealness of the gas in the mixture, the mass concentration of solid particles and the ratio of density of solid particles to the initial density of the gas are investigated.

  7. Influence of near-ultraviolet light enhancement and photosynthetic photon flux density during photoperiod extension on the morphology and lignin content of black spruce seedlings

    International Nuclear Information System (INIS)

    Margolis, H.; Vezina, L.P.; Bellefleur, P.

    1991-01-01

    When containerized black spruce seedlings (Picea mariana (Mill.) B.S.P.) are grown rapidly in greenhouse culture, they sometimes bend over, grow horizontally and become deformed. This phenomenon has been known to affect between 5% and 10% of a winter greenhouse crop. In this study, near-ultraviolet lamps were used to supplement the artificial light received from high-pressure sodium lamps and the effects on seedling morphology and lignin contents were examined. Neither height to diameter ratios nor lignin concentrations were significantly affected by UV radiation flux density. However, seedling biomass, height, root collar diameter, lignin content, and lignin to cellulose ratios of stems were significantly correlated with total photosynthetic photon flux density (PPFD) received during photoperiod extension. Height to diameter ratios were negatively correlated with PPFD during photoperiod enhancement because of a greater relative increase in diameter growth compared with height growth. Neither UV nor PAR flux density affected the percentage of black spruce seedlings having stem deformations greater than 30 ° from the vertical [fr

  8. Spatial variability of shortwave radiative fluxes in the context of snowmelt

    Science.gov (United States)

    Pinker, Rachel T.; Ma, Yingtao; Hinkelman, Laura; Lundquist, Jessica

    2014-05-01

    Snow-covered mountain ranges are a major source of water supply for run-off and groundwater recharge. Snowmelt supplies as much as 75% of surface water in basins of the western United States. Factors that affect the rate of snow melt include incoming shortwave and longwave radiation, surface albedo, snow emissivity, snow surface temperature, sensible and latent heat fluxes, ground heat flux, and energy transferred to the snowpack from deposited snow or rain. The net radiation generally makes up about 80% of the energy balance and is dominated by the shortwave radiation. Complex terrain poses a great challenge for obtaining the needed information on radiative fluxes from satellites due to elevation issues, spatially-variable cloud cover, rapidly changing surface conditions during snow fall and snow melt, lack of high quality ground truth for evaluation of the satellite based estimates, as well as scale issues between the ground observations and the satellite footprint. In this study we utilize observations of high spatial resolution (5-km) as available from the Moderate Resolution Imaging Spectro-radiometer (MODIS) to derive surface shortwave radiative fluxes in complex terrain, with attention to the impact of slopes on the amount of radiation received. The methodology developed has been applied to several water years (January to July during 2003, 2004, 2005 and 2009) over the western part of the United States, and the available information was used to derive metrics on spatial and temporal variability in the shortwave fluxes. It is planned to apply the findings from this study for testing improvements in Snow Water Equivalent (SWE) estimates.

  9. A multigrid Newton-Krylov method for flux-limited radiation diffusion

    International Nuclear Information System (INIS)

    Rider, W.J.; Knoll, D.A.; Olson, G.L.

    1998-01-01

    The authors focus on the integration of radiation diffusion including flux-limited diffusion coefficients. The nonlinear integration is accomplished with a Newton-Krylov method preconditioned with a multigrid Picard linearization of the governing equations. They investigate the efficiency of the linear and nonlinear iterative techniques

  10. Radiation protection aspects of a high flux, fast neutron generator

    International Nuclear Information System (INIS)

    DeLuca, P.M.; Torti, R.P.; Chenevert, G.M.; Tesmer, J.R.; Kelsey, C.A.

    1976-01-01

    During the development and operation of a gas target, DT neutron generator for use in cancer therapy, two radiation hazards were routinely encountered - personnel exposure to neutrons and to tritium. The principal hazard was irradiation by fast neutrons. By assembling the source below ground level, adding shielding and the use of a controlled access, key identification interlock, the neutron hazard has been reduced. With the present source strength of 2 x 10 12 n/sec, an average neutron dose rate in the control room of 20 mrem/hr was measured- a level compatible with a limited run schedule. The second hazard was exposure to tritium in both gaseous and solid forms. A target inventory of 90 Ci, and overall inventory of 500 Ci, and the need to modify and repair the generator present significant potential hazard due to tritium exposure. The use of protective gloves, wipe tests, urine assays, continuous room air monitoring, and equipment decontamination minimized personnel exposure and effectively confined contamination. The dose due to tritium has been ∼ 0.5 rem/year and negligible spread of contamination has occurred

  11. Density ratios in compressions driven by radiation pressure

    International Nuclear Information System (INIS)

    Lee, S.

    1988-01-01

    It has been suggested that in the cannonball scheme of laser compression the pellet may be considered to be compressed by the 'brute force' of the radiation pressure. For such a radiation-driven compression, an energy balance method is applied to give an equation fixing the radius compression ratio K which is a key parameter for such intense compressions. A shock model is used to yield specific results. For a square-pulse driving power compressing a spherical pellet with a specific heat ratio of 5/3, a density compression ratio Γ of 27 is computed. Double (stepped) pulsing with linearly rising power enhances Γ to 1750. The value of Γ is not dependent on the absolute magnitude of the piston power, as long as this is large enough. Further enhancement of compression by multiple (stepped) pulsing becomes obvious. The enhanced compression increases the energy gain factor G for a 100 μm DT pellet driven by radiation power of 10 16 W from 6 for a square pulse power with 0.5 MJ absorbed energy to 90 for a double (stepped) linearly rising pulse with absorbed energy of 0.4 MJ assuming perfect coupling efficiency. (author)

  12. Steady state ensembles of thermal radiation in a layered media with a constant heat flux

    International Nuclear Information System (INIS)

    Budaev, Bair V.; Bogy, David B.

    2013-01-01

    This paper describes steady-state ensembles of thermally excited electromagnetic radiation in nano-scale layered media with a constant non-vanishing heat flux across the layers. It is shown that Planck's law of thermal radiation, the principle of equivalence, and the laws of wave propagation in layered media, imply that in order for the ensemble of thermally excited electromagnetic fields to exist in a medium consisting of a stack of layers between two half-space, the net heat flux across the layers must exceed a certain threshold that is determined by the temperatures of the half spaces and by the reflective properties of the entire structure. The obtained results provide a way for estimating the radiative heat transfer coefficient of nano-scale layered structures. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. A benchmark analysis of radiation flux distribution for Boron Neutron Capture Therapy of canine brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Moran, Jean M. [Univ. of Idaho, Idaho Falls, ID (United States)

    1992-02-01

    Calculations of radiation flux and dose distributions for Boron Neutron Capture Therapy (BNCT) of brain tumors are typically performed using sophisticated three-dimensional analytical models based on either a homogeneous approximation or a simplified few-region approximation to the actual highly-heterogeneous geometry of the irradiation volume. Such models should be validated by comparison with calculations using detailed models in which all significant macroscopic tissue heterogeneities and geometric structures are explicitly represented as faithfully as possible. This work describes a validation exercise for BNCT of canine brain tumors. Geometric measurements of the canine anatomical structures of interest for this work were performed by dissecting and examining two essentially identical Labrador Retriever heads. Chemical analyses of various tissue samples taken during the dissections were conducted to obtain measurements of elemental compositions for tissues of interest. The resulting geometry and tissue composition data were then used to construct a detailed heterogeneous calculational model of the Labrador Retriever head. Calculations of three-dimensional radiation flux distributions pertinent to BNCT were performed for the model using the TORT discrete-ordinates radiation transport code. The calculations were repeated for a corresponding volume-weighted homogeneous tissue model. Comparison of the results showed that the peak neutron and photon flux magnitudes were quite similar for the two models (within 5%), but that the spatial flux profiles were shifted in the heterogeneous model such that the fluxes in some locations away from the peak differed from the corresponding fluxes in the homogeneous model by as much as 10-20%. Differences of this magnitude can be therapeutically significant, emphasizing the need for proper validation of simplified treatment planning models.

  14. A benchmark analysis of radiation flux distribution for Boron Neutron Capture Therapy of canine brain tumors

    International Nuclear Information System (INIS)

    Moran, J.M.

    1992-02-01

    Calculations of radiation flux and dose distributions for Boron Neutron Capture Therapy (BNCT) of brain tumors are typically performed using sophisticated three-dimensional analytical models based on either a homogeneous approximation or a simplified few-region approximation to the actual highly-heterogeneous geometry of the irradiation volume. Such models should be validated by comparison with calculations using detailed models in which all significant macroscopic tissue heterogeneities and geometric structures are explicitly represented as faithfully as possible. This work describes a validation exercise for BNCT of canine brain tumors. Geometric measurements of the canine anatomical structures of interest for this work were performed by dissecting and examining two essentially identical Labrador Retriever heads. Chemical analyses of various tissue samples taken during the dissections were conducted to obtain measurements of elemental compositions for tissues of interest. The resulting geometry and tissue composition data were then used to construct a detailed heterogeneous calculational model of the Labrador Retriever head. Calculations of three-dimensional radiation flux distributions pertinent to BNCT were performed for the model using the TORT discrete-ordinates radiation transport code. The calculations were repeated for a corresponding volume-weighted homogeneous tissue model. Comparison of the results showed that the peak neutron and photon flux magnitudes were quite similar for the two models (within 5%), but that the spatial flux profiles were shifted in the heterogeneous model such that the fluxes in some locations away from the peak differed from the corresponding fluxes in the homogeneous model by as much as 10-20%. Differences of this magnitude can be therapeutically significant, emphasizing the need for proper validation of simplified treatment planning models

  15. Biodistribution parameters and radiation absorbed dose estimates for radiolabeled human low density lipoprotein

    International Nuclear Information System (INIS)

    Hay, R.V.; Ryan, J.W.; Williams, K.A.; Atcher, R.W.; Brechbiel, M.W.; Gansow, O.A.; Fleming, R.M.; Stark, V.J.; Lathrop, K.A.; Harper, P.V.

    1992-01-01

    The authors propose a model to generate radiation absorbed dose estimates for radiolabeled low density lipoprotein (LDL), based upon eight studies of LDL biodistribution in three adult human subjects. Autologous plasma LDL was labeled with Tc-99m, I-123, or In-111 and injected intravenously. Biodistribution of each LDL derivative was monitored by quantitative analysis of scintigrams and direct counting of excreta and of serial blood samples. Assuming that transhepatic flux accounts for the majority of LDL clearance from the bloodstream, they obtained values of cumulated activity (A) and of mean dose per unit administered activity (D) for each study. In each case highest D values were calculated for liver, with mean doses of 5 rads estimated at injected activities of 27 mCi, 9 mCi, and 0.9 mCi for Tc-99m-LDL, I-123-LDL, and In-111-LDL, respectively

  16. Magnetogasdynamic spherical shock wave in a non-ideal gas under gravitational field with conductive and radiative heat fluxes

    Science.gov (United States)

    Nath, G.; Vishwakarma, J. P.

    2016-11-01

    Similarity solutions are obtained for the flow behind a spherical shock wave in a non-ideal gas under gravitational field with conductive and radiative heat fluxes, in the presence of a spatially decreasing azimuthal magnetic field. The shock wave is driven by a piston moving with time according to power law. The radiation is considered to be of the diffusion type for an optically thick grey gas model and the heat conduction is expressed in terms of Fourier's law for heat conduction. Similarity solutions exist only when the surrounding medium is of constant density. The gas is assumed to have infinite electrical conductivity and to obey a simplified van der Waals equation of state. It is shown that an increase of the gravitational parameter or the Alfven-Mach number or the parameter of the non-idealness of the gas decreases the compressibility of the gas in the flow-field behind the shock, and hence there is a decrease in the shock strength. The pressure and density vanish at the inner surface (piston) and hence a vacuum is formed at the center of symmetry. The shock waves in conducting non-ideal gas under gravitational field with conductive and radiative heat fluxes can be important for description of shocks in supernova explosions, in the study of a flare produced shock in the solar wind, central part of star burst galaxies, nuclear explosion etc. The solutions obtained can be used to interpret measurements carried out by space craft in the solar wind and in neighborhood of the Earth's magnetosphere.

  17. Investigation of intermittent magnetic flux in the auroral zones with kilometer radiation (AKR)

    International Nuclear Information System (INIS)

    Liu, S.Q.; Li, X.Q.

    2001-01-01

    On the basis of the nonlinear equations for self-generated magnetic fields, it is numerically shown that the magnetic fields self-generated are instable and may collapse, resulting in spatially highly intermittent flux fragment. Numerical results show that the enhanced magnetic flux has a strength about up to 10 -2 Gauss in range about around 250-350 km in auroral zones with kilometric radiation (AKR), which correspond to estimated values in both the strength and characteristic scale by Mckean et al. [J. Geophys. Res. [Oceans] 96, 21055 (1991)

  18. Influences of biomass heat and biochemical energy storages on the land surface fluxes and radiative temperature

    Science.gov (United States)

    Gu, Lianhong; Meyers, Tilden; Pallardy, Stephen G.; Hanson, Paul J.; Yang, Bai; Heuer, Mark; Hosman, Kevin P.; Liu, Qing; Riggs, Jeffery S.; Sluss, Dan; Wullschleger, Stan D.

    2007-01-01

    The interest of this study was to develop an initial assessment on the potential importance of biomass heat and biochemical energy storages for land-atmosphere interactions, an issue that has been largely neglected so far. We conducted flux tower observations and model simulations at a temperate deciduous forest site in central Missouri in the summer of 2004. The model used was the comprehensive terrestrial ecosystem Fluxes and Pools Integrated Simulator (FAPIS). We first examined FAPIS performance by testing its predictions with and without the representation of biomass energy storages against measurements of surface energy and CO2 fluxes. We then evaluated the magnitudes and temporal patterns of the biomass energy storages calculated by FAPIS. Finally, the effects of biomass energy storages on land-atmosphere exchanges of sensible and latent heat fluxes and variations of land surface radiative temperature were investigated by contrasting FAPIS simulations with and without these storage terms. We found that with the representation of the two biomass energy storage terms, FAPIS predictions agreed with flux tower measurements fairly well; without the representation, however, FAPIS performance deteriorated for all predicted surface energy flux terms although the effect on the predicted CO2 flux was minimal. In addition, we found that the biomass heat storage and biochemical energy storage had clear diurnal patterns with typical ranges from -50 to 50 and -3 to 20 W m-2, respectively; these typical ranges were exceeded substantially when there were sudden changes in atmospheric conditions. Furthermore, FAPIS simulations without the energy storages produced larger sensible and latent heat fluxes during the day but smaller fluxes (more negative values) at night as compared with simulations with the energy storages. Similarly, without-storage simulations had higher surface radiative temperature during the day but lower radiative temperature at night, indicating that the

  19. Electron flux enhancement in the inner radiation belt during moderate magnetic storms

    Directory of Open Access Journals (Sweden)

    H. Tadokoro

    2007-06-01

    Full Text Available During moderate magnetic storms, an electron channel (300–1100 keV of the NOAA satellite has shown sudden electron flux enhancements in the inner radiation belt. After examinating the possibility of contamination by different energetic particles, we conclude that these electron flux enhancements are reliable enough to be considered as natural phenomena, at least for the cases of small to moderate magnetic storms. Here, we define small and moderate storms to be those in which the minimum Dst ranges between −30 and −100 nT. The electron flux enhancements appear with over one order of magnitude at L~2 during these storms. The enhancement is not accompanied by any transport of electron flux from the outer belt. Statistical analysis shows that these phenomena have a duration of approximately 1 day during the period, starting with the main phase to the early recovery phase of the storms. The flux enhancement shows a dawn-dusk asymmetry; the amount of increased flux is larger in the dusk side. We suggest that this phenomenon could not be caused by the radial diffusion but would be due to pitch-angle scattering at the magnetic equator. The inner belt is not in a stationary state, as was previously believed, but is variable in response to the magnetic activity.

  20. Effect of Magnetic Flux Density and Applied Current on Temperature, Velocity and Entropy Generation Distributions in MHD Pumps

    Directory of Open Access Journals (Sweden)

    M. Kiyasatfar

    2011-01-01

    Full Text Available In the present study, simulation of steady state, incompressible and fully developed laminar flow has been conducted in a magneto hydrodynamic (MHD pump. The governing equations are solved numerically by finite-difference method. The effect of the magnetic flux density and current on the flow and temperature distributions in a MHD pump is investigated. The obtained results showed that controlling the flow and the temperature is possible through the controlling of the applied current and the magnetic flux. Furthermore, the effects of the magnetic flux density and current on entropy generation in MHD pump are considered. Our presented numerical results are in good agreement with the experimental data showed in literature.

  1. A state-space modeling approach to estimating canopy conductance and associated uncertainties from sap flux density data

    Science.gov (United States)

    David M. Bell; Eric J. Ward; A. Christopher Oishi; Ram Oren; Paul G. Flikkema; James S. Clark; David Whitehead

    2015-01-01

    Uncertainties in ecophysiological responses to environment, such as the impact of atmospheric and soil moisture conditions on plant water regulation, limit our ability to estimate key inputs for ecosystem models. Advanced statistical frameworks provide coherent methodologies for relating observed data, such as stem sap flux density, to unobserved processes, such as...

  2. Constraining the cosmic radiation density due to lepton number

    International Nuclear Information System (INIS)

    Mangano, Gianpiero; Miele, Gennaro; Pastor, Sergio; Pisanti, Ofelia; Sarikas, Srdjan

    2013-01-01

    The cosmic energy density in the form of radiation before and during Big Bang Nucleosynthesis is typically parameterized in terms of the effective number of neutrinos N eff , and it is a key parameters in cosmological models slightly more general than the successful minimal ΛCDM scenario. This quantity, in case of no extra degrees of freedom, depends upon the chemical potential and the temperature characterizing the three active neutrino distributions, as well as by their possible non-thermal features. We summarize here the results of a recent analysis to determine the BBN bound on N eff from primordial neutrino–antineutrino asymmetries, with a careful treatment of the dynamics of neutrino oscillations, and considering quite a wide range for the total lepton number in the neutrino sector, η ν =η ν e +η ν μ +η ν τ and the initial electron neutrino asymmetry η ν e in . Comparing these results with the forthcoming measurement of N eff by the Planck satellite will give insight on the nature of the radiation content of the universe

  3. High flux and high resolution VUV beam line for synchrotron radiation

    International Nuclear Information System (INIS)

    Wilcke, H.; Boehmer, W.; Schwentner, N.

    1982-04-01

    A beam line has been optimized for high flux and high resolution in the wavelength range from 30 nm to 300 nm. Sample chambers for luminescence spectroscopy on gaseous, liquid and solid samples and for photoelectron spectroscopy have been integrated. The synchrotron radiation from the storage ring DORIS (at DESY, Hamburg) emitted into 50 mrad in horizontal and into 2.2 mrad in vertical direction is focused by a cylindrical and a plane elliptical mirror into the entrance slit of a 2m normal incidence monochromator. The light flux from the exit slit is focused by a rotational elliptic mirror onto the sample yielding a size of the light spot of 4 x 0.15 mm 2 . The light flux at the sample reaches 7 x 10 12 photons nm -1 s -1 at 8 eV photon energy for a current of 100 mA in DORIS. A resolution of 0.007 nm has been obtained. (orig.)

  4. Radiation effects on flow past an impulsively started vertical plate with variable temperature and mass flux

    Directory of Open Access Journals (Sweden)

    Muthucumaraswamy R.

    2005-01-01

    Full Text Available An analysis is performed to study the thermal radiation effects on unsteady free convective flow over a moving vertical plate in the presence of variable temperature and uniform mass flux. The fluid considered here is a gray, absorbing-emitting radiation but a non-scattering medium. The temperature is raised linearly with time and the concentration level near the plate are raised linearly with time. The dimensionless governing equations are solved using the Laplace transform technique. The velocity and skinfriction are studied for different parameters like the radiation parameter, Schmidt number, thermal Grashof number, mass Grashof number and time. It is observed that the velocity increases with decreasing radiation parameter.

  5. Optical design of a high radiative flux solar furnace for Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Riveros-Rosas, D.; Perez-Rabago, C.A.; Arancibia-Bulnes, C.A.; Jaramillo, O.A.; Estrada, C.A. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Av. Xochicalco s/n, A.P. 34, Temixco, 62580 Morelos (Mexico); Herrera-Vazquez, J.; Vazquez-Montiel, S.; Granados-Agustin, F. [Instituto Nacional de Astrofisica, Optica y Electronica, Luis Enrique Erro 1, Tonantzintla, A.P. 216, 72000 Puebla (Mexico); Sanchez-Gonzalez, M. [Centro Nacional de Energias Renovables, Calle Somera 7-9, 28026 Madrid (Spain)

    2010-05-15

    In the present work, the optical design of a new high radiative flux solar furnace is described. Several optical configurations for the concentrator of the system have been considered. Ray tracing simulations were carried out in order to determine the concentrated radiative flux distributions in the focal zone of the system, for comparing the different proposals. The best configuration was chosen in terms of maximum peak concentration, but also in terms of economical and other practical considerations. It consists of an arrangement of 409 first surface spherical facets with hexagonal shape, mounted on a spherical frame. The individual orientation of the facets is corrected in order to compensate for aberrations. The design considers an intercepted power of 30 kW and a target peak concentration above 10,000 suns. The effect of optical errors was also considered in the simulations. (author)

  6. Thermoluminescent dosemeters (TLD) exposed to high fluxes of gamma radiation, thermal neutrons and protons

    International Nuclear Information System (INIS)

    Gambarini, G.; Martini, M.; Meinardi, F.; Raffaglio, C.; Salvadori, P.; Scacco, A.; Sichirollo, A.E.

    1996-01-01

    Thermoluminescent dosemeters (TLD), widely experimented and utilized in personal dosimetry, have some advantageous characteristics which induce one to employ them also in radiotherapy. The new radiotherapy techniques are aimed at selectively depositing a high dose in cancerous tissues. This goal is reached by utilising both conventional and other more recently proposed radiation, such as thermal neutrons and heavy charged particles. In these inhomogeneous radiation fields a reliable mapping of the spatial distribution of absorbed dose is desirable, and the utilized dosemeters have to give such a possibility without notably perturbing the radiation field with the materials of the dosemeters themselves. TLDs, for their small dimension and their tissue equivalence for most radiation, give good support in the mapping of radiation fields. After exposure to the high fluxes of therapeutic beams, some commercial TL dosemeters have shown a loss of reliability. An investigation has therefore be performed, both on commercial and on laboratory made phosphors, in order to investigate their behaviour in such radiation fields. In particular the thermal neutron and gamma ray mixed field of the thermal column of a nuclear reactor, of interest for Boron Neutron Capture Therapy (B.N.C.T.) and a proton beam, of interest for proton therapy, were considered. Here some results obtained with new TL phosphors exposed in such radiation fields are presented, after a short description of some radiation damage effect on commercial LiF TLDs exposed in the (n th ,γ) field of the thermal column of a reactor. (author)

  7. Nonlinear radiative heat flux and heat source/sink on entropy generation minimization rate

    Science.gov (United States)

    Hayat, T.; Khan, M. Waleed Ahmed; Khan, M. Ijaz; Alsaedi, A.

    2018-06-01

    Entropy generation minimization in nonlinear radiative mixed convective flow towards a variable thicked surface is addressed. Entropy generation for momentum and temperature is carried out. The source for this flow analysis is stretching velocity of sheet. Transformations are used to reduce system of partial differential equations into ordinary ones. Total entropy generation rate is determined. Series solutions for the zeroth and mth order deformation systems are computed. Domain of convergence for obtained solutions is identified. Velocity, temperature and concentration fields are plotted and interpreted. Entropy equation is studied through nonlinear mixed convection and radiative heat flux. Velocity and temperature gradients are discussed through graphs. Meaningful results are concluded in the final remarks.

  8. Absorption and Flux Density Measurements in an Iron Plug in R1

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Ragnar; Braun, Josef

    1958-11-15

    Thermal, epithermal and fast neutron fluxes have been measured in a 60 cm long, 'sliced' iron plug, which has been placed in the lower iron lid of the Swedish reactor R1. Au foils, Cu foils, Mn foils, P packets, Cu wires and small Fe cylinders have been used. The gamma flux has been determined with film dosimeters. The measurements have shown that only in the first centimeters of the iron is the activation determined by the thermal flux, which decreases with a relaxation length {lambda}= (1.51 {+-} 0.02) cm. The epithermal flux is entirely predominant already after 10 cm ( {lambda} = 16 cm). The epithermal neutron flux decreases even more slowly than the fast flux ({lambda} = 6.2 cm)

  9. Absorption and Flux Density Measurements in an Iron Plug in R1

    International Nuclear Information System (INIS)

    Nilsson, Ragnar; Braun, Josef

    1958-11-01

    Thermal, epithermal and fast neutron fluxes have been measured in a 60 cm long, 'sliced' iron plug, which has been placed in the lower iron lid of the Swedish reactor R1. Au foils, Cu foils, Mn foils, P packets, Cu wires and small Fe cylinders have been used. The gamma flux has been determined with film dosimeters. The measurements have shown that only in the first centimeters of the iron is the activation determined by the thermal flux, which decreases with a relaxation length λ= (1.51 ± 0.02) cm. The epithermal flux is entirely predominant already after 10 cm ( λ = 16 cm). The epithermal neutron flux decreases even more slowly than the fast flux (λ = 6.2 cm)

  10. A simple formula for the net long-wave radiation flux in the southern Baltic Sea

    Directory of Open Access Journals (Sweden)

    Tomasz Zapadka

    2001-09-01

    Full Text Available This paper discusses problems of estimating the net long-wave radiation flux at the sea surface on the basis of easily measurable meteorological quantities (air and sea surface temperatures, near-surface water vapour pressure, cloudiness. Empirical data and existing formulae are compared. Additionally, an improved formula for the southern Baltic region is introduced, with a systematic error of less than 1 W -2 and a statistical error of less than 20 W -2.

  11. The relation between radio flux density and ionizing ultra-violet flux for HII regions and supernova remnants in the Large Magellanic cloud

    Directory of Open Access Journals (Sweden)

    Filipović M.D.

    2003-01-01

    Full Text Available We present a comparison between the Parkes radio surveys (Filipović et al 1995 and Vacuum Ultra-Violet (VUV surveys (Smith et al. 1987 of the Large Magellanic Clouds (LMC. We have found 72 sources in common in the LMC which are known HII regions (52 and supernova remnants (SNRs (19. Some of these radio sources are associated with two or more UV stellar associations. A comparison of the radio flux densities and ionizing UV flux for HII regions shows a very good correlation, as expected from theory. Many of the Magellanic Clouds (MCs SNRs are embedded in HII regions, so there is also a relation between radio and UV which we attribute to the surrounding HII regions.

  12. Spectral Cauchy characteristic extraction of strain, news and gravitational radiation flux

    International Nuclear Information System (INIS)

    Handmer, Casey J; Szilágyi, Béla; Winicour, Jeffrey

    2016-01-01

    We present a new approach for the Cauchy-characteristic extraction (CCE) of gravitational radiation strain, news function, and the flux of the energy–momentum, supermomentum and angular momentum associated with the Bondi–Metzner–Sachs asymptotic symmetries. In CCE, a characteristic evolution code takes numerical data on an inner worldtube supplied by a Cauchy evolution code, and propagates it outwards to obtain the space–time metric in a neighborhood of null infinity. The metric is first determined in a scrambled form in terms of coordinates determined by the Cauchy formalism. In prior treatments, the waveform is first extracted from this metric and then transformed into an asymptotic inertial coordinate system. This procedure provides the physically proper description of the waveform and the radiated energy but it does not generalize to determine the flux of angular momentum or supermomentum. Here we formulate and implement a new approach which transforms the full metric into an asymptotic inertial frame and provides a uniform treatment of all the radiation fluxes associated with the asymptotic symmetries. Computations are performed and calibrated using the spectral Einstein code. (paper)

  13. Installation for the study of heat transfer with high flux density; Installation d'etude de transmission de chaleur a densite de flux elevee

    Energy Technology Data Exchange (ETDEWEB)

    Robin, M; Schwab, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    As a result of their very low vapor pressure, metals with a low fusion point (sodium, sodium-potassium alloys, etc.) can be used at high temperature, as heating fluids, in installations whose internal pressure is close to atmospheric pressure. Owing to the very high convection coefficients which can be reached with these fluids and to the large temperature differences utilizable, it is possible to produce through the exchange surfaces considerable heat flux densities, of the order of those which exist through the canning of fuel elements in nuclear reactors. The installation described allowed a flux density of more than 200 W/cm{sup 2} to be obtained, the heating fluid being a Na-K alloy (containing 56 per cent by weight of potassium) brought to a temperature around 550 deg. C. (author) [French] Par suite de leur tres faible pression de vapeur, les metaux a bas point de fusion (sodium, alliages sodium-potassium, etc.) peuvent etre utilises a haute temperature, comme fluides de chauffage, dans des installations dont la pression interne est voisine de la pression atmospherique. Grace aux coefficients de convection tres eleves que ces fluides permettent d'atteindre et aux importantes differences de temperature utilisables, il est possible de produire, a travers les surfaces d'echange, des densites de flux de chaleur considerables, de l'ordre de celles qui existent a travers les gaines des elements combustibles des reacteurs nucleaires. L'installation decrite a permis l'obtention d'une densite de flux de plus, de 200 W/cm{sup 2}, le fluide chauffant etant de l'alliage Na-K (a 56 pour cent en poids de potassium) porte a une temperature voisine de 550 deg. C. (auteur)

  14. Effects of tropospheric aerosols on radiative flux calculations at UV and visible wavelengths

    International Nuclear Information System (INIS)

    Grossman, A.S.; Grant, K.E.

    1994-08-01

    The surface fluxes in the wavelength range 175 to 735nm have been calculated for an atmosphere which contains a uniformly mixed aerosol layer of thickness 1km at the earth's surface. Two different aerosol types were considered, a rural aerosol, and an urban aerosol. The visibility range for the aerosol layers was 95 to 15 km. Surface flux ratios (15km/95km) were in agreement with previously published results for the rural aerosol layer to within about 2%. The surface flux ratios vary from 7 to 14% for the rural aerosol layer and from 13 to 23% for the urban aerosol layer over the wavelength range. A tropospheric radiative forcing of about 1.3% of the total tropospheric flux was determined for the 95km to 15km visibility change in the rural aerosol layer, indicating the potential of tropospheric feedback effects on the surface flux changes. This effect was found to be negligible for the urban aerosol layer. Stratospheric layer heating rate changes due to visibility changes in either the rural or urban aerosol layer were found to be negligible

  15. Industrialization of nanocrystalline Fe–Si–B–P–Cu alloys for high magnetic flux density cores

    International Nuclear Information System (INIS)

    Takenaka, Kana; Setyawan, Albertus D.; Sharma, Parmanand; Nishiyama, Nobuyuki; Makino, Akihiro

    2016-01-01

    Nanocrystalline Fe–Si–B–P–Cu alloys exhibit high saturation magnetic flux density (B s ) and extremely low magnetic core loss (W), simultaneously. Low amorphous-forming ability of these alloys hinders their application potential in power transformers and motors. Here we report a solution to this problem. Minor addition of C is found to be effective in increasing the amorphous-forming ability of Fe–Si–B–P–Cu alloys. It allows fabrication of 120 mm wide ribbons (which was limited to less than 40 mm) without noticeable degradation in magnetic properties. The nanocrystalline (Fe 85.7 Si 0.5 B 9.5 P 3.5 Cu 0.8 ) 99 C 1 ribbons exhibit low coercivity (H c )~4.5 A/m, high B s ~1.83 T and low W~0.27 W/kg (@ 1.5 T and 50 Hz). Success in fabrication of long (60–100 m) and wide (~120 mm) ribbons, which are made up of low cost elements is promising for mass production of energy efficient high power transformers and motors - Highlights: • Minor addition of C in FeSiBPCu alloy increases amorphous-forming ability. • The FeSiBPCuC alloy exhibits B s close to Si-steel and Core loss lower than it. • Excellent soft magnetic properties were obtained for 120 mm wide ribbons. • Nanocrystalline FeSiBPCuC alloy can be produced at industrial scale with low cost. • The alloy is suitable for making low energy loss power transformers and motors.

  16. Effect of magnetic flux-densities of up to 0.1 Tesla on copper electrodeposition

    Directory of Open Access Journals (Sweden)

    Cifuentes, L.

    2003-08-01

    Full Text Available The effect of magnetic flux densities (B between 0.0 and 0.1 Tesla on cathode and anode overpotentials, cell voltage and electrodeposit quality was determined for a lab-scale copper electrowinning cell which operates at industrial current density values. Cell voltage decreases with increasing B. The cathodic overpotential decreases by 30 % when B increases from 0.0 to 0.1 T The anodic overpotential also decreases with increasing B, but this effect is six times less than the corresponding effect on the cathodic overpotential. Cathodic effects can be predicted by an expression derived from electrochemical kinetics and magnetohydrodynamic theory. Anodic effects cannot be predicted in the same way. The size of grains and intergranular voids decreases and the surface of the electrodeposit becomes smoother as B increases, which means that, in the studied conditions, the quality of the produced copper deposits improves.

    Se determinó el efecto de densidades de flujo magnético (B de, hasta 0,1 Tesla, sobre los sobrepotenciales catódico y anódico, la tensión de celda y la calidad del electrodepósito en una celda de electroobtención de cobre que opera a valores industriales de densidad de corriente. La tensión de celda decrece al aumentar B. El sobrepotencial catódico disminuye en 30 % cuando B aumenta de 0,0 a 0,1 T El sobrepotencial anódico también disminuye al crecer B, pero este efecto es seis veces menor que en el caso catódico. Los efectos catódicos pueden predecirse por medio de una expresión deducida de la cinética electroquímica y la magnetohidrodinámica. No es posible realizar una predicción análoga de los efectos anódicos. El tamaño de los granos y de los huecos intergranulares decrece y la superficie del electrodepósito se hace más pareja al aumentar B, lo que implica que, en las condiciones estudiadas, la calidad del depósito de cobre mejora.

  17. Modeling the radiative effects of biomass burning aerosols on carbon fluxes in the Amazon region

    Science.gov (United States)

    Moreira, Demerval S.; Longo, Karla M.; Freitas, Saulo R.; Yamasoe, Marcia A.; Mercado, Lina M.; Rosário, Nilton E.; Gloor, Emauel; Viana, Rosane S. M.; Miller, John B.; Gatti, Luciana V.; Wiedemann, Kenia T.; Domingues, Lucas K. G.; Correia, Caio C. S.

    2017-12-01

    Every year, a dense smoke haze covers a large portion of South America originating from fires in the Amazon Basin and central parts of Brazil during the dry biomass burning season between August and October. Over a large portion of South America, the average aerosol optical depth at 550 nm exceeds 1.0 during the fire season, while the background value during the rainy season is below 0.2. Biomass burning aerosol particles increase scattering and absorption of the incident solar radiation. The regional-scale aerosol layer reduces the amount of solar energy reaching the surface, cools the near-surface air, and increases the diffuse radiation fraction over a large disturbed area of the Amazon rainforest. These factors affect the energy and CO2 fluxes at the surface. In this work, we applied a fully integrated atmospheric model to assess the impact of biomass burning aerosols in CO2 fluxes in the Amazon region during 2010. We address the effects of the attenuation of global solar radiation and the enhancement of the diffuse solar radiation flux inside the vegetation canopy. Our results indicate that biomass burning aerosols led to increases of about 27 % in the gross primary productivity of Amazonia and 10 % in plant respiration as well as a decline in soil respiration of 3 %. Consequently, in our model Amazonia became a net carbon sink; net ecosystem exchange during September 2010 dropped from +101 to -104 TgC when the aerosol effects are considered, mainly due to the aerosol diffuse radiation effect. For the forest biome, our results point to a dominance of the diffuse radiation effect on CO2 fluxes, reaching a balance of 50-50 % between the diffuse and direct aerosol effects for high aerosol loads. For C3 grasses and savanna (cerrado), as expected, the contribution of the diffuse radiation effect is much lower, tending to zero with the increase in aerosol load. Taking all biomes together, our model shows the Amazon during the dry season, in the presence of high

  18. Modeling the radiative effects of biomass burning aerosols on carbon fluxes in the Amazon region

    Directory of Open Access Journals (Sweden)

    D. S. Moreira

    2017-12-01

    Full Text Available Every year, a dense smoke haze covers a large portion of South America originating from fires in the Amazon Basin and central parts of Brazil during the dry biomass burning season between August and October. Over a large portion of South America, the average aerosol optical depth at 550 nm exceeds 1.0 during the fire season, while the background value during the rainy season is below 0.2. Biomass burning aerosol particles increase scattering and absorption of the incident solar radiation. The regional-scale aerosol layer reduces the amount of solar energy reaching the surface, cools the near-surface air, and increases the diffuse radiation fraction over a large disturbed area of the Amazon rainforest. These factors affect the energy and CO2 fluxes at the surface. In this work, we applied a fully integrated atmospheric model to assess the impact of biomass burning aerosols in CO2 fluxes in the Amazon region during 2010. We address the effects of the attenuation of global solar radiation and the enhancement of the diffuse solar radiation flux inside the vegetation canopy. Our results indicate that biomass burning aerosols led to increases of about 27 % in the gross primary productivity of Amazonia and 10 % in plant respiration as well as a decline in soil respiration of 3 %. Consequently, in our model Amazonia became a net carbon sink; net ecosystem exchange during September 2010 dropped from +101 to −104 TgC when the aerosol effects are considered, mainly due to the aerosol diffuse radiation effect. For the forest biome, our results point to a dominance of the diffuse radiation effect on CO2 fluxes, reaching a balance of 50–50 % between the diffuse and direct aerosol effects for high aerosol loads. For C3 grasses and savanna (cerrado, as expected, the contribution of the diffuse radiation effect is much lower, tending to zero with the increase in aerosol load. Taking all biomes together, our model shows the Amazon during the dry

  19. A dynamo theory prediction for solar cycle 22: Sunspot number, radio flux, exospheric temperature, and total density at 400 km

    Science.gov (United States)

    Schatten, K. H.; Hedin, A. E.

    1986-01-01

    Using the dynamo theory method to predict solar activity, a value for the smoothed sunspot number of 109 + or - 20 is obtained for solar cycle 22. The predicted cycle is expected to peak near December, 1990 + or - 1 year. Concommitantly, F(10.7) radio flux is expected to reach a smoothed value of 158 + or - 18 flux units. Global mean exospheric temperature is expected to reach 1060 + or - 50 K and global total average total thermospheric density at 400 km is expected to reach 4.3 x 10 to the -15th gm/cu cm + or - 25 percent.

  20. A dynamo theory prediction for solar cycle 22 - Sunspot number, radio flux, exospheric temperature, and total density at 400 km

    Science.gov (United States)

    Schatten, K. H.; Hedin, A. E.

    1984-01-01

    Using the 'dynamo theory' method to predict solar activity, a value for the smoothed sunspot number of 109 + or - 20 is obtained for solar cycle 22. The predicted cycle is expected to peak near December, 1990 + or - 1 year. Concommitantly, F(10.7) radio flux is expected to reach a smoothed value of 158 + or - 18 flux units. Global mean exospheric temperature is expected to reach 1060 + or - 50 K and global total average total thermospheric density at 400 km is expected to reach 4.3 x 10 to the -15th gm/cu cm + or - 25 percent.

  1. Effect of density distribution of cathode emission on the flux character in a strong-current electron gun

    International Nuclear Information System (INIS)

    Matora, I.M.; Merkulov, L.A.

    1975-01-01

    The effect is considered of two kinds of a dependence of the emission density from the electric field voltage on the emitter surface of a strong-current electron gun (the Schottky law and the ''3/2'' law) upon the choice of a form for the meridional cross section of this emitter at the condition of electron flux laminarity. A calculation example is given for electron gun with close to laminar flow assuming the validity of the Schottky law. The results of calculation of varying the laminar flux character are given which appears when varying parameters of the gun at the voltage 500 kV and current 250 A

  2. High Density Nano-Electrode Array for Radiation Detection

    International Nuclear Information System (INIS)

    Misra, Mano

    2010-01-01

    Bulk single crystals of Cd 1-x Zn x Te (x=0.04 to x=0.2) compound semiconductor is used for room temperature radiation detection. The production of large volume of Cd 1-x Zn x Te with low defect density is expensive. As a result there is a growing research interest in the production of nanostructured compound semiconductors such as Cd 1-x Zn x Te in an electrochemical route. In this investigation, Cd 1-x Zn x Te ternary compound semiconductor, referred as CZT, was electrodeposited in the form of nanowires onto a TiO 2 nanotubular template from propylene carbonate as the non-aqueous electrolyte, using a pulse-reverse electrodeposition process at 130 C. The template acted as a support in growing ordered nanowire of CZT which acts as a one dimensional conductor. Cyclic Voltammogram (CV) studies were conducted in determining the potentials for the growth of nanowires of uniform stoichiometry. The morphologies and composition of CZT were characterized by using SEM, TEM and XRD. The STEM mapping carried out on the nanowires showed the uniform distribution of Cd, Zn and Te elements. TEM image showed that the nanowires were polycrystalline in nature. The Mott-Schottky analysis carried on the nanowires showed that the nanowires were a p-type semiconductor. The carrier density, band gap and resistivity of the Cd 0.9 Zn 0.1 Te nanowires were 4.29 x 10 13 cm -3 , 1.56 eV and 2.76 x 10 11 (Omega)-cm respectively. The high resistivity was attributed to the presence of deep defect states such as cadmium vacancies or Te antisites which were created by the anodic cycle of the pulse-reverse electrodeposition process. Stacks of series connected CZT nanowire arrays were tested with different bias potentials. The background current was in the order of tens of picoamperes. When exposed to radiation source Amerecium-241 (60 KeV, 4 (micro)Ci), the stacked CZT nanowires arrays showed sensing behavior. The sensitivity of the nanowire arrays increased as the number of stacks increased. The

  3. High Density Nano-Electrode Array for Radiation Detection

    Energy Technology Data Exchange (ETDEWEB)

    Mano Misra

    2010-05-07

    Bulk single crystals of Cd1-xZnxTe (x=0.04 to x=0.2) compound semiconductor is used for room temperature radiation detection. The production of large volume of Cd1-xZnxTe with low defect density is expensive. As a result there is a growing research interest in the production of nanostructured compound semiconductors such as Cd1-xZnxTe in an electrochemical route. In this investigation, Cd1-xZnxTe ternary compound semiconductor, referred as CZT, was electrodeposited in the form of nanowires onto a TiO2 nanotubular template from propylene carbonate as the non-aqueous electrolyte, using a pulse-reverse electrodeposition process at 130 ºC. The template acted as a support in growing ordered nanowire of CZT which acts as a one dimensional conductor. Cyclic Voltammogram (CV) studies were conducted in determining the potentials for the growth of nanowires of uniform stoichiometry. The morphologies and composition of CZT were characterized by using SEM, TEM and XRD. The STEM mapping carried out on the nanowires showed the uniform distribution of Cd, Zn and Te elements. TEM image showed that the nanowires were polycrystalline in nature. The Mott-Schottky analysis carried on the nanowires showed that the nanowires were a p-type semiconductor. The carrier density, band gap and resistivity of the Cd0.9Zn0.1Te nanowires were 4.29x1013 cm-3, 1.56 eV and 2.76x1011Ω-cm respectively. The high resistivity was attributed to the presence of deep defect states such as cadmium vacancies or Te antisites which were created by the anodic cycle of the pulse-reverse electrodeposition process. Stacks of series connected CZT nanowire arrays were tested with different bias potentials. The background current was in the order of tens of picoamperes. When exposed to radiation source Amerecium-241 (60 KeV, 4 μCi), the stacked CZT nanowires arrays showed sensing behavior. The sensitivity of the nanowire arrays increased as the number of stacks increased. The preliminary results indicate that the

  4. Optimization of multiply acquired magnetic flux density B{sub z} using ICNE-Multiecho train in MREIT

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Hyun Soo; Kwon, Oh In [Department of Mathematics, Konkuk University, Seoul (Korea, Republic of)

    2010-05-07

    The aim of magnetic resonance electrical impedance tomography (MREIT) is to visualize the electrical properties, conductivity or current density of an object by injection of current. Recently, the prolonged data acquisition time when using the injected current nonlinear encoding (ICNE) method has been advantageous for measurement of magnetic flux density data, Bz, for MREIT in the signal-to-noise ratio (SNR). However, the ICNE method results in undesirable side artifacts, such as blurring, chemical shift and phase artifacts, due to the long data acquisition under an inhomogeneous static field. In this paper, we apply the ICNE method to a gradient and spin echo (GRASE) multi-echo train pulse sequence in order to provide the multiple k-space lines during a single RF pulse period. We analyze the SNR of the measured multiple B{sub z} data using the proposed ICNE-Multiecho MR pulse sequence. By determining a weighting factor for B{sub z} data in each of the echoes, an optimized inversion formula for the magnetic flux density data is proposed for the ICNE-Multiecho MR sequence. Using the ICNE-Multiecho method, the quality of the measured magnetic flux density is considerably increased by the injection of a long current through the echo train length and by optimization of the voxel-by-voxel noise level of the B{sub z} value. Agarose-gel phantom experiments have demonstrated fewer artifacts and a better SNR using the ICNE-Multiecho method. Experimenting with the brain of an anesthetized dog, we collected valuable echoes by taking into account the noise level of each of the echoes and determined B{sub z} data by determining optimized weighting factors for the multiply acquired magnetic flux density data.

  5. Effects of magnetic flux densities on microstructure evolution and magnetic properties of molecular-beam-vapor-deposited nanocrystalline Fe_3_0Ni_7_0 thin films

    International Nuclear Information System (INIS)

    Cao, Yongze; Wang, Qiang; Li, Guojian; Ma, Yonghui; Du, Jiaojiao; He, Jicheng

    2015-01-01

    Nanocrystalline Fe_3_0Ni_7_0 (in atomic %) thin films were prepared by molecular-beam-vapor deposition in magnetic fields with different magnetic flux densities. The microstructure evolution of these thin films was studied by atomic force microscopy, transmission electron microscopy, and high resolution transmission electron microscopy; the soft magnetic properties were examined by vibrating sample magnetometer at room temperature. The results show that all our Fe_3_0Ni_7_0 thin films feature an fcc single-phase structure. With increasing magnetic flux density, surface roughness, average particle size and grain size of the thin films decreased, and the short-range ordered clusters (embryos) of thin films increased. Additionally, the magnetic anisotropy in the in-plane and the coercive forces of the thin films gradually reduced with increasing magnetic flux density. - Highlights: • With increasing magnetic flux density, average particle size of films decreased. • With increasing magnetic flux density, surface roughness of thin films decreased. • With increasing magnetic flux density, short-range ordered clusters increased. • With increasing magnetic flux density, the coercive forces of thin films reduced. • With increasing magnetic flux density, soft magnetic properties are improved.

  6. Exact solution of thermal radiation on vertical oscillating plate with variable temperature and mass flux

    Directory of Open Access Journals (Sweden)

    Muthucumaraswamy R.

    2010-01-01

    Full Text Available Thermal radiation effects on unsteady flow past an infinite vertical oscillating plate in the presence of variable temperature and uniform mass flux is considered. The fluid considered here is a gray, absorbing-emitting radiation but a non-scattering medium. The plate temperature is raised linearly with time and the mass is diffused from the plate to the fluid at an uniform rate. The dimensionless governing equations are solved using the Laplace transform technique. The velocity, concentration and temperature are studied for different physical parameters like the phase angle, radiation parameter, Schmidt number, thermal Grashof number, mass Grashof number and time. It is observed that the velocity increases with decreasing phase angle ωt.

  7. Impact of melting heat transfer and nonlinear radiative heat flux mechanisms for the generalized Burgers fluids

    Directory of Open Access Journals (Sweden)

    Waqar Azeem Khan

    Full Text Available The present paper deals with the analysis of melting heat and mass transfer characteristics in the stagnation point flow of an incompressible generalized Burgers fluid over a stretching sheet in the presence of non-linear radiative heat flux. A uniform magnetic field is applied normal to the flow direction. The governing equations in dimensional form are reduced to a system of dimensionless expressions by implementation of suitable similarity transformations. The resulting dimensionless problem governing the generalized Burgers is solved analytically by using the homotopy analysis method (HAM. The effects of different flow parameters like the ratio parameter, magnetic parameter, Prandtl number, melting parameter, radiation parameter, temperature ratio parameter and Schmidt number on the velocity, heat and mass transfer characteristics are computed and presented graphically. Moreover, useful discussions in detail are carried out with the help of plotted graphs and tables. Keywords: Generalized Burgers fluid, Non-linear radiative flow, Magnetic field, Melting heat transfer

  8. Boiling transition and the possibility of spontaneous nucleation under high subcooling and high mass flux density flow in a tube

    International Nuclear Information System (INIS)

    Fukuyama, Y.; Kuriyama, T.; Hirata, M.

    1986-01-01

    Boiling transition and inverted annular heat transfer for R-113 have been investigated experimentally in a horizontal tube of 1.2 X 10/sup -3/ meter inner diameter with heating length over inner diameter ratio of 50. Experiments cover a high mass flux density range, a high local subcooling range and a wide local pressure range. Heat transfer characteristics were obtained by using heat flux control steady-state apparatus. Film boiling treated here is limited to the case of inverted annular heat transfer with very thin vapor film, on the order of 10/sup -6/ meter. Moreover, film boiling region is always limited to a certain downstream part, since the system has a pressure gradient along the flow direction. Discussions are presented on the parametric trends of boiling heat transfer characteristic curves and characteristic points. The possible existence is suggested of a spontaneous nucleation control surface boiling phenomena. And boiling transition heat flux and inverted annular heat transfer were correlated

  9. On the Relationship Between High Speed Solar Wind Streams and Radiation Belt Electron Fluxes

    Science.gov (United States)

    Zheng, Yihua

    2011-01-01

    Both past and recent research results indicate that solar wind speed has a close connection to radiation belt electron fluxes [e.g., Paulikas and Blake, 1979; Reeves et aI., 2011]: a higher solar wind speed is often associated with a higher level of radiation electron fluxes. But the relationship can be very complex [Reeves et aI., 2011]. The study presented here provides further corroboration of this viewpoint by emphasizing the importance of a global perspective and time history. We find that all the events during years 2010 and 2011 where the >0.8 MeV integral electron flux exceeds 10(exp 5) particles/sq cm/sr/s (pfu) at GEO orbit are associated with the high speed streams (HSS) following the onset of the Stream Interaction Region (SIR), with most of them belonging to the long-lasting Corotating Interaction Region (CIR). Our preliminary results indicate that during HSS events, a maximum speed of 700 km/s and above is a sufficient but not necessary condition for the > 0.8 MeV electron flux to reach 10(exp 5) pfu. But in the exception cases of HSS events where the electron flux level exceeds the 10(exp 5) pfu value but the maximum solar wind speed is less than 700 km/s, a prior impact can be noted either from a CME or a transient SIR within 3-4 days before the arrival of the HSS - stressing the importance of time history. Through superposed epoch analysis and studies providing comparisons with the CME events and the HSS events where the flux level fails to reach the 10(exp 5) pfu, we will present the quantitative assessment of behaviors and relationships of various quantities, such as the time it takes to reach the flux threshold value from the stream interface and its dependence on different physical parameters (e.g., duration of the HSS event, its maximum or average of the solar wind speed, IMF Bz, Kp). The ultimate goal is to apply what is derived to space weather forecasting.

  10. Placed in a steady magnetic field, the flux density inside a permalloy-shielded volume decreases over hours and days

    Science.gov (United States)

    Feinberg, Benedict; Gould, Harvey

    2018-03-01

    Following the application of an external magnetic field to a thin-walled demagnetized Permalloy cylinder, the magnetic flux density at the center of the shielded volume decreases by roughly 20% over periods of hours to days. We measured this effect for applied magnetic fields from 0.48 A/m to 16 A/m, the latter being comparable to the Earths magnetic field at its weakest point. Delayed changes in magnetic flux density are also observed following alternating current demagnetization. We attribute these effects to delayed changes in magnetization, which have previously been observed in thin Permalloy films and small bulk samples of ferromagnetic materials. Phenomenological models of thermal activation are discussed. Some possible effects on experiments that rely on static shielding are noted.

  11. Effects of water salinity on the correlation scale of Root density and Evapotranspiration fluxes

    Science.gov (United States)

    Ajeel, Ali; Saeed, Ali; Dragonetti, Giovanna; Comegna, Alessandro; Lamaddalena, Nicola; Coppola, Antonio

    2015-04-01

    Spatial pattern and the correlation of different soil and plant parameters were examined in a green bean field experiment carried out at the Mediterranean Agronomic Institute of Bari, Italy. The experiment aimed to evaluate the role of local processes of salt accumulation and transport which mainly influences the evapotranspiration (and thus the root uptake) processes under different water salinity levels. The experiment consisted of three transects of 30m length and 4.2 m width, irrigated with three different salinity levels (1dSm-1, 3dSm-1, 6dSm-1). Soil measurements (electrical conductivity and soil water content) were monitored along transects in 24 sites, 1 m apart by using TDR probes and Diviner 2000. Water storage measured by TDR and Diviner sensor were coupled for calculating directly the evapotranspiration fluxes along the whole soil profile under the different salinity levels imposed during the experiment. In the same sites, crop monitoring involved measurements of Leaf Area Index (LAI), Osmotic Potential (OP), Leaf Water Potential (LWP), and Root length Density (RlD). Soil and plant properties were analyzed by classical statistics, geostatistics methods and spectral analysis. Results indicated moderate to large spatial variability across the field for soil and plant parameters under all salinity treatments. Furthermore, cross-semivariograms exhibited a strong positive spatial interdependence between electrical conductivity of soil solution ECw with ET and RlD in transect treated with 3dSm-1 as well as with LAI in transect treated with 6dSm-1 at all 24 monitoring sites. Spectral analysis enabled to identify the observation window to sample the soil salinity information responsible for a given plant response (ET, OP, RlD). It is also allowed a clear identification of the spatial scale at which the soil water salinity level and distribution and the crop response in terms of actual evapotranspiration ET, RlD and OP, are actually correlated. Additionally

  12. The influence of the number of activation detectors on the Seibersdorf - Milano intercomparison of neutron flux density spectra by WINDOWS code

    International Nuclear Information System (INIS)

    Ertek, C.

    1981-02-01

    This work is a continuation of the work performed within the IAEA programme on standardization of reactor radiation measurements, one of the important objectives of which is the assistance to laboratories in Member States to implement or intercompare the multiple foil activation techniques for different neutron field measurements. The importance of these techniques is well recognized. In CESNEF-FERMI Politecnico di Milano, Italy, they have installed near the core of a water boiler of 50kW, a neutron filter made of B 4 C in order to obtain a neutron flux density spectrum that could be of utility in intercalibration problems connected with irradiation in fast assemblies. Dr. V. Sangiust from CESNEF kindly sent the input guess neutron flux density spectrum and a series of measured reaction rates to be treated by the IAEA Seibersdorf laboratory using the SAND-II and the WINDOWS unfolding codes. The meaningful comparison using partly the same ENDF/B IV cross section data is performed. In the present work we extended the investiga tion using WINDOWS unfolding code for different numbers of activation fo ils or reaction rates

  13. Magnetic flux density distribution in superconducting cylinders of arbitrary cross section subjected to an axial magnetic field

    Science.gov (United States)

    Fournet, G.

    1982-07-01

    We show here how the application of the critical state model allows one to determine the magnetic flux density B⃗ in each point of a superconducting cylinder with an arbitrary cross section subjected to axial magnetic fields Hz; the B = 0 boundaries of the regions occupied by the vortices are so defined. We successively consider the cases where the critical current density Jc is either isotropic (constant or an arbitrary function of B) or tensorial, which means, for our problem, the use of two components Jcx and Jcy (either constant or depending on B but Jcx/Jcy remaining constant).

  14. Optimizing Power Density and Efficiency of a Double-Halbach Array Permanent-Magnet Ironless Axial-Flux Motor

    Science.gov (United States)

    Duffy, Kirsten P.

    2016-01-01

    NASA Glenn Research Center is investigating hybrid electric and turboelectric propulsion concepts for future aircraft to reduce fuel burn, emissions, and noise. Systems studies show that the weight and efficiency of the electric system components need to be improved for this concept to be feasible. This effort aims to identify design parameters that affect power density and efficiency for a double-Halbach array permanent-magnet ironless axial flux motor configuration. These parameters include both geometrical and higher-order parameters, including pole count, rotor speed, current density, and geometries of the magnets, windings, and air gap.

  15. Parallel-plate submicron gap formed by micromachined low-density pillars for near-field radiative heat transfer

    International Nuclear Information System (INIS)

    Ito, Kota; Miura, Atsushi; Iizuka, Hideo; Toshiyoshi, Hiroshi

    2015-01-01

    Near-field radiative heat transfer has been a subject of great interest due to the applicability to thermal management and energy conversion. In this letter, a submicron gap between a pair of diced fused quartz substrates is formed by using micromachined low-density pillars to obtain both the parallelism and small parasitic heat conduction. The gap uniformity is validated by the optical interferometry at four corners of the substrates. The heat flux across the gap is measured in a steady-state and is no greater than twice of theoretically predicted radiative heat flux, which indicates that the parasitic heat conduction is suppressed to the level of the radiative heat transfer or less. The heat conduction through the pillars is modeled, and it is found to be limited by the thermal contact resistance between the pillar top and the opposing substrate surface. The methodology to form and evaluate the gap promotes the near-field radiative heat transfer to various applications such as thermal rectification, thermal modulation, and thermophotovoltaics

  16. Reanalyses of the radiation belt electron phase space density using nearly equatorial CRRES and polar-orbiting Akebono satellite observations

    Science.gov (United States)

    Ni, Binbin; Shprits, Yuri; Nagai, Tsugunobu; Thorne, Richard; Chen, Yue; Kondrashov, Dmitri; Kim, Hee-jeong

    2009-05-01

    Data assimilation techniques provide algorithms that allow for blending of incomplete and inaccurate data with physics-based dynamic models to reconstruct the electron phase space density (PSD) in the radiation belts. In this study, we perform reanalyses of the radial PSD profile using two independent data sources from the nearly equatorial CRRES Medium Electron A (MEA) observations and the polar-orbiting Akebono Radiation Monitor (RDM) measurements for a 50-day period from 18 August to 6 October 1990. We utilize the University of California, Los Angeles, One-Dimensional Versatile Electron Radiation Belt (UCLA 1-D VERB) code and a Kalman filtering approach. Comparison of the reanalyses obtained independently using the CRRES MEA and Akebono RDM measurements shows that the dynamics of the PSD can be accurately reconstructed using Kalman filtering even when available data are sparse, inaccurate, and contaminated by random errors. The reanalyses exhibit similarities in the locations and magnitudes of peaks in radial profiles of PSD and the rate and radial extent of the dropouts during storms. This study shows that when unidirectional data are not available, pitch angle averaged flux measurements can be used to infer the long-term behavior (climatology) of the radiation belts. The methodology of obtaining PSD from pitch angle averaged and unidirectional fluxes using the Tsyganenko and Stern (1996) magnetic field model is described in detail.

  17. Parallel-plate submicron gap formed by micromachined low-density pillars for near-field radiative heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Kota, E-mail: kotaito@mosk.tytlabs.co.jp [Toyota Central Research and Development Laboratories, Nagakute, Aichi 480-1192 (Japan); Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Miura, Atsushi; Iizuka, Hideo [Toyota Central Research and Development Laboratories, Nagakute, Aichi 480-1192 (Japan); Toshiyoshi, Hiroshi [Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8904 (Japan)

    2015-02-23

    Near-field radiative heat transfer has been a subject of great interest due to the applicability to thermal management and energy conversion. In this letter, a submicron gap between a pair of diced fused quartz substrates is formed by using micromachined low-density pillars to obtain both the parallelism and small parasitic heat conduction. The gap uniformity is validated by the optical interferometry at four corners of the substrates. The heat flux across the gap is measured in a steady-state and is no greater than twice of theoretically predicted radiative heat flux, which indicates that the parasitic heat conduction is suppressed to the level of the radiative heat transfer or less. The heat conduction through the pillars is modeled, and it is found to be limited by the thermal contact resistance between the pillar top and the opposing substrate surface. The methodology to form and evaluate the gap promotes the near-field radiative heat transfer to various applications such as thermal rectification, thermal modulation, and thermophotovoltaics.

  18. Use of ordinary kriging and Gaussian conditional simulation to interpolate airborne fire radiative energy density estimates

    Science.gov (United States)

    C. Klauberg; A. T. Hudak; B. C. Bright; L. Boschetti; M. B. Dickinson; R. L. Kremens; C. A. Silva

    2018-01-01

    Fire radiative energy density (FRED, J m-2) integrated from fire radiative power density (FRPD, W m-2) observations of landscape-level fires can present an undersampling problem when collected from fixed-wing aircraft. In the present study, the aircraft made multiple passes over the fire at ~3 min intervals, thus failing to observe most of the FRPD emitted as the flame...

  19. Preliminary investigation of changes in x-ray multilayer optics subjected to high radiation flux

    International Nuclear Information System (INIS)

    Hockaday, M.P.; Blake, R.L.; Grosso, J.S.; Selph, M.M.; Klein, M.M.; Matuska, W. Jr.; Palmer, M.A.; Liefeld, R.J.

    1985-01-01

    A variety of metal multilayers was exposed to high x-ray flux using Sandia National Laboratories' PROTO II machine in the gas puff mode. Fluxes incident on the multilayers above 700 MW/cm 2 in total radiation, in nominal 20 ns pulses, were realized. The neon hydrogen- and helium-like resonance lines were used to probe the x-ray reflectivity properties of the multilayers as they underwent change of state during the heating pulse. A fluorescer-fiber optic-streak camera system was used to monitor the changes in x-ray reflectivity as a function of time and irradiance. Preliminary results are presented for a W/C multilayer. Work in progress to model the experiment is discussed. 13 refs., 4 figs

  20. Circular heat and momentum flux radiated by magneto-optical nanoparticles

    Science.gov (United States)

    Ott, A.; Ben-Abdallah, P.; Biehs, S.-A.

    2018-05-01

    In the present article we investigate the heat and momentum fluxes radiated by a hot magneto-optical nanoparticle in its surroundings under the action of an external magnetic field. We show that the flux lines circulate in a confined region at a nanometric distance from the particle around the axis of the magnetic field in a vortexlike configuration. Moreover we prove that the spatial orientation of these vortices (clockwise or counterclockwise) is associated with the contribution of optical resonances with topological charges m =+1 or m =-1 to the thermal emission. This work paves the way for a geometric description of heat and momentum transport in lattices of magneto-optical particles. Moreover it could have important applications in the field of energy storage as well as in thermal management at nanoscale.

  1. Experimental studies and modelling of high radiation and high density plasmas in the ASDEX upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Casali, Livia

    2015-11-24

    Fusion plasmas contain impurities, either intrinsic originating from the wall, or injected willfully with the aim of reducing power loads on machine components by converting heat flux into radiation. The understanding and the prediction of the effects of these impurities and their radiation on plasma performances is crucial in order to retain good confinement. In addition, it is important to understand the impact of pellet injection on plasma performance since this technique allows higher core densities which are required to maximise the fusion power. This thesis contributes to these efforts through both experimental investigations and modelling. Experiments were conducted at ASDEX Upgrade which has a full-W wall. Impurity seeding was applied to H-modes by injecting nitrogen and also medium-Z impurities such as Kr and Ar to assess the impact of both edge and central radiation on confinement. A database of about 25 discharges has been collected and analysed. A wide range of plasma parameters was achieved up to ITER relevant values such as high Greenwald and high radiation fractions. Transport analyses taking into account the radiation distribution reveal that edge localised radiation losses do not significantly impact confinement as long as the H-mode pedestal is sustained. N seeding induces higher pedestal pressure which is propagated to the core via profile stiffness. Central radiation must be limited and controlled to avoid confinement degradation. This requires reliable control of the impurity concentration but also possibilities to act on the ELM frequency which must be kept high enough to avoid an irreversible impurity accumulation in the centre and the consequent radiation collapse. The key role of the f{sub ELM} is confirmed also by the analysis of N+He discharges. Non-coronal effects affect the radiation of low-Z impurities at the plasma edge. Due to the radial transport, the steep temperature gradients and the ELM flush out, a local equilibrium cannot be

  2. Evaluation of HFIR [High Flux Isotope Reactor] pressure-vessel integrity considering radiation embrittlement

    International Nuclear Information System (INIS)

    Cheverton, R.D.; Merkle, J.G.; Nanstad, R.K.

    1988-04-01

    The High Flux Isotope Reactor (HFIR) pressure vessel has been in service for 20 years, and during this time, radiation damage was monitored with a vessel-material surveillance program. In mid-November 1986, data from this program indicated that the radiation-induced reduction in fracture toughness was greater than expected. As a result, a reevaluation of vessel integrity was undertaken. Updated methods of fracture-mechanics analysis were applied, and an accelerated irradiations program was conducted using the Oak Ridge Research Reactor. Results of these efforts indicate that (1) the vessel life can be extended 10 years if the reactor power level is reduced 15% and if the vessel is subjected to a hydrostatic proof test each year; (2) during the 10-year life extension, significant radiation damage will be limited to a rather small area around the beam tubes; and (3) the greater-than-expected damage rate is the result of the very low neutron flux in the HFIR vessel relative to that in samples of material irradiated in materials-testing reactors (a factor of ∼10 4 less), that is, a rate effect

  3. Fixed-target particle fluxes and radiation levels at SSC energies

    International Nuclear Information System (INIS)

    Dukes, E.C.

    1993-01-01

    The author calculates the charged particle fluxes and radiation doses from minimum ionizing particles (MIP), electromagnetic showers, and hadronic showers, in a fixed-target experiment at the SSC. This work follows the work of Groom, essentially boosting his results into the laboratory frame. The radiation in dense matter, such as a calorimeter, is produced by several sources: electromagnetic showers, hadronic showers, and minimum ionizing particles. The author does not consider other sources of radiation such as beam halo, a dependent effects, and low energy neutrons from secondary sources. Nor does he consider the effects of magnetic fields. Low energy neutrons have been shown to be an important source of radiation for collider experiments at the SSC. In fixed-target experiments, where the spectrometer is more open and where most detector elements are far away from secondary particle dumps, these sources are not as important. They are also very much detector and experimental hall dependent. Hence the results presented here are only a lower limit of the estimated radiation dose

  4. Radiation power profiles and density limit with a divertor in the W7-AS stellarator

    International Nuclear Information System (INIS)

    Giannone, L.; Burhenn, R.; McCormick, K.; Brakel, R.; Feng, Y.; Grigull, P.; Igitkhanov, Y.

    2002-01-01

    The addition of a divertor into the W7-AS stellarator has allowed access to a high density regime where the radiation profiles reach a steady state. In earlier limiter discharges, the plasma suffered a radiative collapse at high densities. In contrast to limiter experiments, where the impurity confinement time measured by Al laser blow-off increased with increasing line integrated density, in divertor discharges, above a density threshold, the impurity confinement time decreased with increasing line integrated density. The observation that the divertor plasma radiates mainly at the plasma edge rather than the plasma centre is a further indication that changes to the impurity transport coefficients at these high densities are the basis for the achievement of steady state discharges in the divertor configuration of W7-AS. The maximum line integrated density reached with a divertor is compared to that reached with a limiter. The previously derived scaling law for the density limit with a limiter shows that the achieved densities do not exceed those predicted when the higher deposited power is taken into account. In a divertor the radiated power is located at the plasma edge and increasing the density, cooling the plasma edge and radiating sufficient power to cause plasma detachment determines the density limit. (author)

  5. Modification of low density polyethylene, isostatic polypropylene and their blends by gamma radiation

    International Nuclear Information System (INIS)

    Santos Rosa, D. dos

    1991-01-01

    The effects of the gamma radiation (of a 60 Co source), over low density polyethylene, isostatic polypropylene and their blends of low density polyethylene / polypropylene were studied. The structures modifications were attended by infrared spectrometry (IV), differential scanning calorimeter (DSC), strain-strain measurement, density measurement and scanning electron microscope (SEM). (author)

  6. Estimation of transient heat flux density during the heat supply of a catalytic wall steam methane reformer

    Science.gov (United States)

    Settar, Abdelhakim; Abboudi, Saïd; Madani, Brahim; Nebbali, Rachid

    2018-02-01

    Due to the endothermic nature of the steam methane reforming reaction, the process is often limited by the heat transfer behavior in the reactors. Poor thermal behavior sometimes leads to slow reaction kinetics, which is characterized by the presence of cold spots in the catalytic zones. Within this framework, the present work consists on a numerical investigation, in conjunction with an experimental one, on the one-dimensional heat transfer phenomenon during the heat supply of a catalytic-wall reactor, which is designed for hydrogen production. The studied reactor is inserted in an electric furnace where the heat requirement of the endothermic reaction is supplied by electric heating system. During the heat supply, an unknown heat flux density, received by the reactive flow, is estimated using inverse methods. In the basis of the catalytic-wall reactor model, an experimental setup is engineered in situ to measure the temperature distribution. Then after, the measurements are injected in the numerical heat flux estimation procedure, which is based on the Function Specification Method (FSM). The measured and estimated temperatures are confronted and the heat flux density which crosses the reactor wall is determined.

  7. Sap flow measurements combining sap-flux density radial profiles with punctual sap-flux density measurements in oak trees (Quercus ilex and Quercus pyrenaica) - water-use implications in a water-limited savanna-

    Science.gov (United States)

    Reyes, J. Leonardo; Lubczynski1, Maciek W.

    2010-05-01

    Sap flow measurement is a key aspect for understanding how plants use water and their impacts on the ecosystems. A variety of sensors have been developed to measure sap flow, each one with its unique characteristics. When the aim of a research is to have accurate tree water use calculations, with high temporal and spatial resolution (i.e. scaled), a sensor with high accuracy, high measurement efficiency, low signal-to-noise ratio and low price is ideal, but such has not been developed yet. Granier's thermal dissipation probes (TDP) have been widely used in many studies and various environmental conditions because of its simplicity, reliability, efficiency and low cost. However, it has two major flaws when is used in semi-arid environments and broad-stem tree species: it is often affected by high natural thermal gradients (NTG), which distorts the measurements, and it cannot measure the radial variability of sap-flux density in trees with sapwood thicker than two centimeters. The new, multi point heat field deformation sensor (HFD) is theoretically not affected by NTG, and it can measure the radial variability of the sap flow at different depths. However, its high cost is a serious limitation when simultaneous measurements are required in several trees (e.g. catchment-scale studies). The underlying challenge is to develop a monitoring schema in which HFD and TDP are combined to satisfy the needs of measurement efficiency and accuracy in water accounting. To assess the level of agreement between TDP and HFD methods in quantifying sap flow rates and temporal patterns on Quercus ilex (Q.i ) and Quercus pyrenaica trees (Q.p.), three measurement schemas: standard TDP, TDP-NTG-corrected and HFD were compared in dry season at the semi-arid Sardon area, near Salamanca in Spain in the period from June to September 2009. To correct TDP measurements with regard to radial sap flow variability, a radial sap flux density correction factor was applied and tested by adjusting TDP

  8. Magnetogasdynamics shock waves in a rotational axisymmetric non-ideal gas with increasing energy and conductive and radiative heat-fluxes

    Science.gov (United States)

    Nath, Gorakh

    2016-07-01

    Self-similar solutions are obtained for one-dimensional adiabatic flow behind a magnetogasdynamics cylindrical shock wave propagating in a rotational axisymmetric non ideal gas with increasing energy and conductive and radiative heat fluxes in presence of an azimuthal magnetic field. The fluid velocities and the azimuthal magnetic field in the ambient medium are assume to be varying and obeying power laws. In order to find the similarity solutions the angular velocity of the ambient medium is taken to be decreasing as the distance from the axis increases. The heat conduction is expressed in terms of Fourier's law and the radiation is considered to be the diffusion type for an optically thick grey gas model. The thermal conductivity and the absorption coefficient are assumed to vary with temperature and density. The effects of the presence of radiation and conduction, the non-idealness of the gas and the magnetic field on the shock propagation and the flow behind the shock are investigated.

  9. The FluxCompensator: Making Radiative Transfer Models of Hydrodynamical Simulations Directly Comparable to Real Observations

    Energy Technology Data Exchange (ETDEWEB)

    Koepferl, Christine M.; Robitaille, Thomas P., E-mail: koepferl@usm.lmu.de [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)

    2017-11-01

    When modeling astronomical objects throughout the universe, it is important to correctly treat the limitations of the data, for instance finite resolution and sensitivity. In order to simulate these effects, and to make radiative transfer models directly comparable to real observations, we have developed an open-source Python package called the FluxCompensator that enables the post-processing of the output of 3D Monte Carlo radiative transfer codes, such as Hyperion. With the FluxCompensator, realistic synthetic observations can be generated by modeling the effects of convolution with arbitrary point-spread functions, transmission curves, finite pixel resolution, noise, and reddening. Pipelines can be applied to compute synthetic observations that simulate observatories, such as the Spitzer Space Telescope or the Herschel Space Observatory . Additionally, this tool can read in existing observations (e.g., FITS format) and use the same settings for the synthetic observations. In this paper, we describe the package as well as present examples of such synthetic observations.

  10. The FluxCompensator: Making Radiative Transfer Models of Hydrodynamical Simulations Directly Comparable to Real Observations

    Science.gov (United States)

    Koepferl, Christine M.; Robitaille, Thomas P.

    2017-11-01

    When modeling astronomical objects throughout the universe, it is important to correctly treat the limitations of the data, for instance finite resolution and sensitivity. In order to simulate these effects, and to make radiative transfer models directly comparable to real observations, we have developed an open-source Python package called the FluxCompensator that enables the post-processing of the output of 3D Monte Carlo radiative transfer codes, such as Hyperion. With the FluxCompensator, realistic synthetic observations can be generated by modeling the effects of convolution with arbitrary point-spread functions, transmission curves, finite pixel resolution, noise, and reddening. Pipelines can be applied to compute synthetic observations that simulate observatories, such as the Spitzer Space Telescope or the Herschel Space Observatory. Additionally, this tool can read in existing observations (e.g., FITS format) and use the same settings for the synthetic observations. In this paper, we describe the package as well as present examples of such synthetic observations.

  11. The excess flux in the cosmic submillimeter background radiation and the primordial deuterium abundance

    International Nuclear Information System (INIS)

    Dermer, C.D.; Guessoum, N.; National Aeronautics and Space Administration, Greenbelt, MD

    1989-01-01

    Recent measurements of the cosmic background radiation (CBR) show an enhanced flux in the submillimeter regime, compared to the spectrum of a 2.7 K blackbody. Thermal Comptonization of the relic radiation by a hot nonrelativistic plasma has long been known to produce distortions in the CBR spectrum, similar to what has now been observed. Heating of the primeval plasma to temperatures T ∼ 10 6 - 10 8 K could result from the injection of subcosmic ray protons at epoch z ∼ 10--100. The intensity of the subcosmic ray flux that provide conditions needed to explain the submillimeter excess by thermal Comptonization also leads to the production of cosmologically significant amounts of deuterium in collisions between subcosmic ray protons and primordial protons and α-particles. However, the amount of lithium produced through α-α reactions is in conflict with the observed Li abundance. If lithium is depleted, for example, by processing through Population II stars, arguments for the baryon content of the universe based on primordial deuterium and He abundances are weakened. 12 refs., 1 fig., 1 tab

  12. Radiation Hardness tests with neutron flux on different Silicon photomultiplier devices

    Science.gov (United States)

    Cattaneo, P. W.; Cervi, T.; Menegolli, A.; Oddone, M.; Prata, M.; Prata, M. C.; Rossella, M.

    2017-07-01

    Radiation hardness is an important requirement for solid state readout devices operating in high radiation environments common in particle physics experiments. The MEG II experiment, at PSI, Switzerland, investigates the forbidden decay μ+ → e+ γ. Exploiting the most intense muon beam of the world. A significant flux of non-thermal neutrons (kinetic energy Ek>= 0.5 MeV) is present in the experimental hall produced along the beam-line and in the hall itself. We present the effects of neutron fluxes comparable to the MEG II expected doses on several Silicon Photomultiplier (SiPMs). The tested models are: AdvanSiD ASD-NUV3S-P50 (used in MEG II experiment), AdvanSiD ASD-NUV3S-P40, AdvanSiD ASD-RGB3S-P40, Hamamatsu and Excelitas C30742-33-050-X. The neutron source is the thermal Sub-critical Multiplication complex (SM1) moderated with water, located at the University of Pavia (Italy). We report the change of SiPMs most important electric parameters: dark current, dark pulse frequency, gain, direct bias resistance, as a function of the integrated neutron fluency.

  13. Self similar flow behind an exponential shock wave in a self-gravitating, rotating, axisymmetric dusty gas with heat conduction and radiation heat flux

    Science.gov (United States)

    Bajargaan, Ruchi; Patel, Arvind

    2018-04-01

    One-dimensional unsteady adiabatic flow behind an exponential shock wave propagating in a self-gravitating, rotating, axisymmetric dusty gas with heat conduction and radiation heat flux, which has exponentially varying azimuthal and axial fluid velocities, is investigated. The shock wave is driven out by a piston moving with time according to an exponential law. The dusty gas is taken to be a mixture of a non-ideal gas and small solid particles. The density of the ambient medium is assumed to be constant. The equilibrium flow conditions are maintained and energy is varying exponentially, which is continuously supplied by the piston. The heat conduction is expressed in the terms of Fourier's law, and the radiation is assumed of diffusion type for an optically thick grey gas model. The thermal conductivity and the absorption coefficient are assumed to vary with temperature and density according to a power law. The effects of the variation of heat transfer parameters, gravitation parameter and dusty gas parameters on the shock strength, the distance between the piston and the shock front, and on the flow variables are studied out in detail. It is interesting to note that the similarity solution exists under the constant initial angular velocity, and the shock strength is independent from the self gravitation, heat conduction and radiation heat flux.

  14. Low-density, radiatively inefficient rotating-accretion flow on to a black hole

    Science.gov (United States)

    Inayoshi, Kohei; Ostriker, Jeremiah P.; Haiman, Zoltán; Kuiper, Rolf

    2018-05-01

    We study low-density axisymmetric accretion flows on to black holes (BHs) with two-dimensional hydrodynamical simulations, adopting the α-viscosity prescription. When the gas angular momentum is low enough to form a rotationally supported disc within the Bondi radius (RB), we find a global steady accretion solution. The solution consists of a rotational equilibrium distribution around r ˜ RB, where the density follows ρ ∝ (1 + RB/r)3/2, surrounding a geometrically thick and optically thin accretion disc at the centrifugal radius RC(radiation cooling, where \\dot{M}_Edd is the Eddington accretion rate. In a hot plasma at the bottom (r < 10-3 RB), thermal conduction would dominate the convective energy flux. Since suppression of the accretion by convection ceases, the final BH feeding rate is found to be \\dot{M}/\\dot{M}_B˜ 10^{-3}-10-2. This rate is as low as \\dot{M}/\\dot{M}_Edd˜ 10^{-7}-10-6 inferred for SgrA* and the nuclear BHs in M31 and M87, and can explain their low luminosities, without invoking any feedback mechanism.

  15. Turbulent mass flux closure modeling for variable density turbulence in the wake of an air-entraining transom stern

    Science.gov (United States)

    Hendrickson, Kelli; Yue, Dick

    2016-11-01

    This work presents the development and a priori testing of closure models for the incompressible highly-variable density turbulent (IHVDT) flow in the near wake region of a transom stern. This complex, three-dimensional flow includes three regions with distinctly different flow behavior: (i) the convergent corner waves that originate from the body and collide on the ship center plane; (ii) the "rooster tail" that forms from the collision; and (iii) the diverging wave train. The characteristics of these regions involve violent free-surface flows and breaking waves with significant turbulent mass flux (TMF) at Atwood number At = (ρ2 -ρ1) / (ρ2 +ρ1) 1 for which there is little guidance in turbulence closure modeling for the momentum and scalar transport along the wake. Utilizing datasets from high-resolution simulations of the near wake of a canonical three-dimensional transom stern using conservative Volume-of-Fluid (cVOF), implicit Large Eddy Simulation (iLES), and Boundary Data Immersion Method (BDIM), we develop explicit algebraic turbulent mass flux closure models that incorporate the most relevant physical processes. Performance of these models in predicting the turbulent mass flux in all three regions of the wake will be presented. Office of Naval Research.

  16. Tractable flux-driven temperature, density, and rotation profile evolution with the quasilinear gyrokinetic transport model QuaLiKiz

    Science.gov (United States)

    Citrin, J.; Bourdelle, C.; Casson, F. J.; Angioni, C.; Bonanomi, N.; Camenen, Y.; Garbet, X.; Garzotti, L.; Görler, T.; Gürcan, O.; Koechl, F.; Imbeaux, F.; Linder, O.; van de Plassche, K.; Strand, P.; Szepesi, G.; Contributors, JET

    2017-12-01

    Quasilinear turbulent transport models are a successful tool for prediction of core tokamak plasma profiles in many regimes. Their success hinges on the reproduction of local nonlinear gyrokinetic fluxes. We focus on significant progress in the quasilinear gyrokinetic transport model QuaLiKiz (Bourdelle et al 2016 Plasma Phys. Control. Fusion 58 014036), which employs an approximated solution of the mode structures to significantly speed up computation time compared to full linear gyrokinetic solvers. Optimisation of the dispersion relation solution algorithm within integrated modelling applications leads to flux calculations × {10}6-7 faster than local nonlinear simulations. This allows tractable simulation of flux-driven dynamic profile evolution including all transport channels: ion and electron heat, main particles, impurities, and momentum. Furthermore, QuaLiKiz now includes the impact of rotation and temperature anisotropy induced poloidal asymmetry on heavy impurity transport, important for W-transport applications. Application within the JETTO integrated modelling code results in 1 s of JET plasma simulation within 10 h using 10 CPUs. Simultaneous predictions of core density, temperature, and toroidal rotation profiles for both JET hybrid and baseline experiments are presented, covering both ion and electron turbulence scales. The simulations are successfully compared to measured profiles, with agreement mostly in the 5%-25% range according to standard figures of merit. QuaLiKiz is now open source and available at www.qualikiz.com.

  17. A DETERMINATION OF THE FLUX DENSITY IN CORE OF DISTRIBUTION TRANSFORMERS, WHAT BUILT WITH THE COMMON USING OF GRAIN AND NON GRAIN ORIENTED MAGNETIC STEELS

    Directory of Open Access Journals (Sweden)

    I.V. Pentegov

    2015-12-01

    Full Text Available Purpose. The development of calculation method to determinate the flux densities in different parts of the magnetic cores of distribution transformers, what built from different types magnetic steel (mixed core. Methodology. The method is based on the scientific positions of Theoretical Electrical Engineering – the theory of the electromagnetic field in nonlinear mediums to determine the distribution of magnetic flux in mixed core of transformer, what are using different types of steel what have the different magnetic properties. Results. The developed method gives possible to make calculation of the flux density and influence of skin effect in different parts of the magnetic cores of distribution transformer, where are used mix of grain oriented (GO and non grain oriented (NGO steels. Was determinate the general basic conditions for the calculation of flux density in the laminations from grain and non grain oriented steels of the magnetic core: the strength of magnetic field for the laminations of particular part of mixed core is the same; the sum of the magnetic fluxes in GO and NGO steels in particular part of mixed core is equal with the designed magnetic flux in this part of mixed core. Discover, the magnetic flux in mixed core of the transformer has specific distribution between magnetic steels. The flux density is higher in laminations from GO steel and smaller in laminations from the NGO steel. That is happened because for magnetic flux is easier pass through laminations from GO steel, what has better magnetic conductance than laminations from NGO steel. Originality. The common using of different types of magnetic steels in cores for distribution transformers gives possibility to make design of transformer with low level of no load losses, high efficiency and with optimal cost. Practical value. The determination of the flux density in different parts of magnetic core with GO and NGO steels gives possibility make accurate calculation of

  18. The anisotropy of the cosmic background radiation from local dynamic density perturbations

    International Nuclear Information System (INIS)

    Dyer, C.C.; Ip, P.S.S.

    1988-01-01

    Contrary to the usual assumption, it is shown here that the anisotropy of the cosmic background radiation need not be dominated by perturbations at the last scattering surface. The results of computer simulations are shown in which local dynamic density perturbations, in the form of Swiss cheese holes with finite, uniform density central lumps, are the main source of anisotropy of the cosmic background radiation. (author)

  19. Systems with a constant heat flux with applications to radiative heat transport across nanoscale gaps and layers

    Science.gov (United States)

    Budaev, Bair V.; Bogy, David B.

    2018-06-01

    We extend the statistical analysis of equilibrium systems to systems with a constant heat flux. This extension leads to natural generalizations of Maxwell-Boltzmann's and Planck's equilibrium energy distributions to energy distributions of systems with a net heat flux. This development provides a long needed foundation for addressing problems of nanoscale heat transport by a systematic method based on a few fundamental principles. As an example, we consider the computation of the radiative heat flux between narrowly spaced half-spaces maintained at different temperatures.

  20. Responses of Sap Flux Density to Changing Atmospheric Humidity in Three Common Street Tree Species in Bangkok, Thailand

    Directory of Open Access Journals (Sweden)

    Pantana Tor-ngern

    2016-09-01

    Full Text Available Efficient water management in urban landscape is imperative under the projected increases in drought stress under future climate. Because different tree species have different stomatal regulations to prevent water loss under water limitation, comparative study of species-specific responses of water use to changing weather conditions will benefit selective planting of urban trees for sustainable urban greening management. Here, we performed a simple and short-term investigation of water use characteristics of three common street tree species in Bangkok, a major city in Southeast Asia. Species included Pterocarpus indicus (Pi, Swietenia macrophylla (Sm and Lagerstroemia speciosa (Ls. We used self-constructed heat dissipation probes to track water uptake rates, expressed as sap flux density (JS, in stems of potted trees and examined their diurnal variations with changing atmospheric humidity, represented by vapor pressure deficit (D. The results implied that two of the three species: Pi and Sm, may be selected for planting because their Js was less sensitive to changing D compared to Ls. The sap flux density of Ls increased more rapidly with rising D, implying higher sensitivity to drought in Ls, compared to the other two species. Nevertheless, further study on large trees and under longer period of investigation, covering both dry and wet seasons, is required to confirm this finding.

  1. High-flux normal incidence monochromator for circularly polarized synchrotron radiation

    International Nuclear Information System (INIS)

    Schaefers, F.; Peatman, W.; Eyers, A.; Heckenkamp, C.; Schoenhense, G.; Heinzmann, U.

    1986-01-01

    A 6.5-m normal incidence monochromator installed at the storage ring BESSY, which is optimized for a high throughput of circularly polarized off-plane radiation at moderate resolution is described. The monochromator employs two exit slits and is specially designed and used for low-signal experiments such as spin- and angle-resolved photoelectron spectroscopy on solids, adsorbates, free atoms, and molecules. The Monk--Gillieson mounting (plane grating in a convergent light beam) allows for large apertures with relatively little astigmatism. With two gratings, a flux of more than 10 11 photons s -1 bandwidth -1 (0.2--0.5 nm) with a circular polarization of more than 90% in the wavelength range from 35 to 675 nm is achieved

  2. Mesoscale model parameterizations for radiation and turbulent fluxes at the lower boundary

    International Nuclear Information System (INIS)

    Somieski, F.

    1988-11-01

    A radiation parameterization scheme for use in mesoscale models with orography and clouds has been developed. Broadband parameterizations are presented for the solar and the terrestrial spectral ranges. They account for clear, turbid or cloudy atmospheres. The scheme is one-dimensional in the atmosphere, but the effects of mountains (inclination, shading, elevated horizon) are taken into account at the surface. In the terrestrial band, grey and black clouds are considered. Furthermore, the calculation of turbulent fluxes of sensible and latent heat and momentum at an inclined lower model boundary is described. Surface-layer similarity and the surface energy budget are used to evaluate the ground surface temperature. The total scheme is part of the mesoscale model MESOSCOP. (orig.) With 3 figs., 25 refs [de

  3. Sap flux density and stomatal conductance of European beech and common oak trees in pure and mixed stands during the summer drought of 2003

    Science.gov (United States)

    Jonard, F.; André, F.; Ponette, Q.; Vincke, C.; Jonard, M.

    2011-10-01

    SummarySap flux density of European beech and common oak trees was determined from sap flow measurements in pure and mixed stands during the summer drought of 2003. Eight trees per species and per stand were equipped with sap flow sensors. Soil water content was monitored in each stand at different depths by using time-domain reflectometry (TDR). Leaf area index and vertical root distribution were also investigated during the growing season. From sap flux density ( SFD) data, mean stomatal conductance of individual trees ( G s) was calculated by inverting the Penman-Monteith equation. Linear mixed models were developed to analyse the effects of species and stand type (pure vs. mixed) on SFD and G s and on their sensitivity to environmental variables (vapour pressure deficit ( D), incoming solar radiation ( R G), and relative extractable water ( REW)). For reference environmental conditions, we did not find any tree species or stand type effects on SFD. The sensitivity of SFD to D was higher for oak than for beech in the pure stands ( P sapwood-to-leaf area ratio compared to oak. The sensitivity of G s to REW was higher for beech than for oak and was ascribed to a higher vulnerability of beech to air embolism and to a more sensitive stomatal regulation. The sensitivity of beech G s to REW was lower in the mixed than in the pure stand, which could be explained by a better sharing of the resources in the mixture, by facilitation processes (hydraulic lift), and by a rainfall partitioning in favour of beech.

  4. The LMJ project - status of our knowledge in hohlraum energetics physics: production and control of the radiation flux

    International Nuclear Information System (INIS)

    Dattolo, E.

    2001-09-01

    CEA-DAM in France is working on Inertial controlled Fusion (ICF) since the beginning of nineties. In an indirect drive scheme, the laser light is converted in X-ray in a hohlraum made with an high-Z material. Part of this radiation flux is absorbed by a micro-balloon filled with DT, placed in the center of the hohlraum, and generates its implosion, ignition and burn. This paper gives the status of our knowledge and studies for production and control of the radiation flux in the hohlraum, in the perspective of the Laser MegaJoule (LMJ). (authors)

  5. Far scrape-off layer particle and heat fluxes in high density

    DEFF Research Database (Denmark)

    Müller, H. W.; Bernert, M.; Carralero, D.

    2014-01-01

    The far scrape-off layer transport is studied in ASDEX Upgrade H-mode discharges with high divertor neutral density N0,div, high power across the separatrix Psep and nitrogen seeding to control the divertor temperature. Such conditions are expected for ITER but usually not investigated in terms...

  6. Advantages and Limits of 4H-SIC Detectors for High- and Low-Flux Radiations

    Science.gov (United States)

    Sciuto, A.; Torrisi, L.; Cannavò, A.; Mazzillo, M.; Calcagno, L.

    2017-11-01

    Silicon carbide (SiC) detectors based on Schottky diodes were used to monitor low and high fluxes of photons and ions. An appropriate choice of the epilayer thickness and geometry of the surface Schottky contact allows the tailoring and optimizing the detector efficiency. SiC detectors with a continuous front electrode were employed to monitor alpha particles in a low-flux regime emitted by a radioactive source with high energy (>5.0 MeV) or generated in an ion implanter with sub-MeV energy. An energy resolution value of 0.5% was measured in the high energy range, while, at energy below 1.0 MeV, the resolution becomes 10%; these values are close to those measured with a traditional silicon detector. The same SiC devices were used in a high-flux regime to monitor high-energy ions, x-rays and electrons of the plasma generated by a high-intensity (1016 W/cm2) pulsed laser. Furthermore, SiC devices with an interdigit Schottky front electrode were proposed and studied to overcome the limits of the such SiC detectors in the detection of low-energy (˜1.0 keV) ions and photons of the plasmas generated by a low-intensity (1010 W/cm2) pulsed laser. SiC detectors are expected to be a powerful tool for the monitoring of radioactive sources and ion beams produced by accelerators, for a complete characterization of radiations emitted from laser-generated plasmas at high and low temperatures, and for dosimetry in a radioprotection field.

  7. High-Density Signal Interface Electromagnetic Radiation Prediction for Electromagnetic Compatibility Evaluation.

    Energy Technology Data Exchange (ETDEWEB)

    Halligan, Matthew

    2017-11-01

    Radiated power calculation approaches for practical scenarios of incomplete high- density interface characterization information and incomplete incident power information are presented. The suggested approaches build upon a method that characterizes power losses through the definition of power loss constant matrices. Potential radiated power estimates include using total power loss information, partial radiated power loss information, worst case analysis, and statistical bounding analysis. A method is also proposed to calculate radiated power when incident power information is not fully known for non-periodic signals at the interface. Incident data signals are modeled from a two-state Markov chain where bit state probabilities are derived. The total spectrum for windowed signals is postulated as the superposition of spectra from individual pulses in a data sequence. Statistical bounding methods are proposed as a basis for the radiated power calculation due to the statistical calculation complexity to find a radiated power probability density function.

  8. Flux-probability distributions from the master equation for radiation transport in stochastic media

    International Nuclear Information System (INIS)

    Franke, Brian C.; Prinja, Anil K.

    2011-01-01

    We present numerical investigations into the accuracy of approximations in the master equation for radiation transport in discrete binary random media. Our solutions of the master equation yield probability distributions of particle flux at each element of phase space. We employ the Levermore-Pomraning interface closure and evaluate the effectiveness of closures for the joint conditional flux distribution for estimating scattering integrals. We propose a parameterized model for this joint-pdf closure, varying between correlation neglect and a full-correlation model. The closure is evaluated for a variety of parameter settings. Comparisons are made with benchmark results obtained through suites of fixed-geometry realizations of random media in rod problems. All calculations are performed using Monte Carlo techniques. Accuracy of the approximations in the master equation is assessed by examining the probability distributions for reflection and transmission and by evaluating the moments of the pdfs. The results suggest the correlation-neglect setting in our model performs best and shows improved agreement in the atomic-mix limit. (author)

  9. Comparing convective heat fluxes derived from thermodynamics to a radiative-convective model and GCMs

    Science.gov (United States)

    Dhara, Chirag; Renner, Maik; Kleidon, Axel

    2015-04-01

    The convective transport of heat and moisture plays a key role in the climate system, but the transport is typically parameterized in models. Here, we aim at the simplest possible physical representation and treat convective heat fluxes as the result of a heat engine. We combine the well-known Carnot limit of this heat engine with the energy balances of the surface-atmosphere system that describe how the temperature difference is affected by convective heat transport, yielding a maximum power limit of convection. This results in a simple analytic expression for convective strength that depends primarily on surface solar absorption. We compare this expression with an idealized grey atmosphere radiative-convective (RC) model as well as Global Circulation Model (GCM) simulations at the grid scale. We find that our simple expression as well as the RC model can explain much of the geographic variation of the GCM output, resulting in strong linear correlations among the three approaches. The RC model, however, shows a lower bias than our simple expression. We identify the use of the prescribed convective adjustment in RC-like models as the reason for the lower bias. The strength of our model lies in its ability to capture the geographic variation of convective strength with a parameter-free expression. On the other hand, the comparison with the RC model indicates a method for improving the formulation of radiative transfer in our simple approach. We also find that the latent heat fluxes compare very well among the approaches, as well as their sensitivity to surface warming. What our comparison suggests is that the strength of convection and their sensitivity in the climatic mean can be estimated relatively robustly by rather simple approaches.

  10. Seeding magnetic fields for laser-driven flux compression in high-energy-density plasmas.

    Science.gov (United States)

    Gotchev, O V; Knauer, J P; Chang, P Y; Jang, N W; Shoup, M J; Meyerhofer, D D; Betti, R

    2009-04-01

    A compact, self-contained magnetic-seed-field generator (5 to 16 T) is the enabling technology for a novel laser-driven flux-compression scheme in laser-driven targets. A magnetized target is directly irradiated by a kilojoule or megajoule laser to compress the preseeded magnetic field to thousands of teslas. A fast (300 ns), 80 kA current pulse delivered by a portable pulsed-power system is discharged into a low-mass coil that surrounds the laser target. A >15 T target field has been demonstrated using a hot spot of a compressed target. This can lead to the ignition of massive shells imploded with low velocity-a way of reaching higher gains than is possible with conventional ICF.

  11. Comparison between measured and computed magnetic flux density distribution of simulated transformer core joints assembled from grain-oriented and non-oriented electrical steel

    Directory of Open Access Journals (Sweden)

    Hamid Shahrouzi

    2018-04-01

    Full Text Available The flux distribution in an overlapped linear joint constructed in the central region of an Epstein Square was studied experimentally and results compared with those obtained using a computational magnetic field solver. High permeability grain-oriented (GO and low permeability non-oriented (NO electrical steels were compared at a nominal core flux density of 1.60 T at 50 Hz. It was found that the experimental results only agreed well at flux densities at which the reluctance of different paths of the flux are similar. Also it was revealed that the flux becomes more uniform when the working point of the electrical steel is close to the knee point of the B-H curve of the steel.

  12. Methyl halide fluxes from tropical plants under controlled radiation and temperature regimes

    Science.gov (United States)

    Blei, Emanuel; Yokouchi, Yoko; Saito, Takuya; Nozoe, Susumu

    2015-04-01

    Methyl halides (CH3Cl, CH3Br, CH3I) contribute significantly to the halogen burden of the atmosphere and have the potential to influence the stratospheric ozone layer through their catalytic effect in the Chapman cycle. As such they have been studied over the years, and many plants and biota have been examined for their potential to act as a source of these gases. One of the potentially largest terrestrial sources identified was tropical vegetation such as tropical ferns and Dipterocarp trees. Most of these studies concentrated on the identification and quantification of such fluxes rather than their characteristics and often the chambers used in these studies were either opaque or only partially transparent to the full solar spectrum. Therefore it is not certain to which degree emissions of methyl halides are innate to the plants and how much they might vary due to radiation or temperature conditions inside the enclosures. In a separate development it had been proposed that UV-radiation could cause live plant materials to be become emitters of methane even under non-anoxic conditions. As methane is chemically very similar to methyl halides and had been proposed to be produced from methyl-groups ubiquitously found in plant cell material there is a relatively good chance that such a production mechanism would also apply to methyl halides. To test whether radiation can affect elevated emissions of methyl halides from plant materials and to distinguish this from temperature effects caused by heat build-up in chambers a set of controlled laboratory chamber enclosures under various radiation and temperature regimes was conducted on four different tropical plant species (Magnolia grandiflora, Cinnamonum camphora, Cyathea lepifera, Angiopteris lygodiifolia), the latter two of which had previously been identified as strong methyl halide emitters. Abscised leaf samples of these species were subjected to radiation treatments such UV-B, UV-A and broad spectrum radiation

  13. Transport simulations of a density limit in radiation-dominated tokamak discharges: II

    International Nuclear Information System (INIS)

    Stotler, D.P.

    1991-05-01

    The procedures developed previously to simulate the radiatively induced tokamak density limit are used to examine in more detail the scaling of the density limit. It is found that the maximum allowable density increases with auxiliary power and decreases with impurity concentration. However, it is demonstrated that there is little dependence of the density limit on plasma elongation. These trends are consistent with experimental results. Our previous work used coronal equilibrium impurities; the primary result of that paper was that the maximum density increases with current when peaked profiles are assumed. Here, this behavior is shown to occur with a coronal nonequilibrium impurity as well. 26 refs., 4 figs

  14. Level Densities and Radiative Strength Functions in 170,171Yb

    International Nuclear Information System (INIS)

    Agvaanluvsan, U.; Schiller, A.; Becker, J.A.; Berstein, L.A.; Guttormsen, M.; Mitchell, G.E.; Rekstad, J.; Siem, S.; Voinov, A.

    2003-01-01

    Level densities and radiative strength functions in 171 Yb and 170 Yb nuclei have been measured with the 171 Yb( 3 He, 3 He(prime) γ) 171 Yb and 171 Yb( 3 He, αγ) 170 Yb reactions. A simultaneous determination of the nuclear level density and the radiative strength function was made. The present data adds to and is consistent with previous results for several other rare earth nuclei. The method will be briefly reviewed and the result from the analysis will be presented. The radiative strength function for 171 Yb is compared to previously published work.

  15. Effects of radiation and thermal diffusivity on heat transfer over a stretching surface with variable heat flux

    International Nuclear Information System (INIS)

    Seddeek, M.A.; Abdelmeguid, M.S.

    2006-01-01

    The effect of radiation and thermal diffusivity on heat transfer over a stretching surface with variable heat flux has been studied. The thermal diffusivity is assumed to vary as a linear function of temperature. The governing partial differential equations have been transformed to ordinary differential equations. The exact analytical solution for the velocity and the numerical solution for the temperature field are given. Numerical solutions are obtained for different values of variable thermal diffusivity, radiation, temperature parameter and Prandtl number

  16. Optimization of a partially non-magnetic primary radiation shielding for the triple-axis spectrometer PANDA at the Munich high-flux reactor FRM-II

    CERN Document Server

    Pyka, N M; Rogov, A

    2002-01-01

    Monte Carlo simulations have been used to optimize the monochromator shielding of the polarized cold-neutron triple-axis spectrometer PANDA at the Munich high-flux reactor FRM-II. By using the Monte Carlo program MCNP-4B, the density of the total spectrum of incoming neutrons and gamma radiation from the beam tube SR-2 has been determined during the three-dimensional diffusion process in different types of heavy concrete and other absorbing material. Special attention has been paid to build a compact and highly efficient shielding, partially non-magnetic, with a total biological radiation dose of less than 10 mu Sv/h at its outsides. Especially considered was the construction of an albedo reducer, which serves to reduce the background in the experiment outside the shielding. (orig.)

  17. Variability in radial sap flux density patterns and sapwood area among seven co-occurring temperate broad-leaved tree species.

    Science.gov (United States)

    Gebauer, Tobias; Horna, Viviana; Leuschner, Christoph

    2008-12-01

    Forest transpiration estimates are frequently based on xylem sap flux measurements in the outer sections of the hydro-active stem sapwood. We used Granier's constant-heating technique with heating probes at various xylem depths to analyze radial patterns of sap flux density in the sapwood of seven broad-leaved tree species differing in wood density and xylem structure. Study aims were to (1) compare radial sap flux density profiles between diffuse- and ring-porous trees and (2) analyze the relationship between hydro-active sapwood area and stem diameter. In all investigated species except the diffuse-porous beech (Fagus sylvatica L.) and ring-porous ash (Fraxinus excelsior L.), sap flux density peaked at a depth of 1 to 4 cm beneath the cambium, revealing a hump-shaped curve with species-specific slopes. Beech and ash reached maximum sap flux densities immediately beneath the cambium in the youngest annual growth rings. Experiments with dyes showed that the hydro-active sapwood occupied 70 to 90% of the stem cross-sectional area in mature trees of diffuse-porous species, whereas it occupied only about 21% in ring-porous ash. Dendrochronological analyses indicated that vessels in the older sapwood may remain functional for 100 years or more in diffuse-porous species and for up to 27 years in ring-porous ash. We conclude that radial sap flux density patterns are largely dependent on tree species, which may introduce serious bias in sap-flux-derived forest transpiration estimates, if non-specific sap flux profiles are assumed.

  18. Transport simulations of a density limit in radiation-dominated tokamak discharges: profile effects

    International Nuclear Information System (INIS)

    Stotler, D.P.

    1988-01-01

    The density limit observed in tokamak experiments is thought to be due to a radiative collapse of the current channel. A transport code coupled with a magnetohydrodynamic (MHD) equilibrium routine is used to determine the detailed, self-consistent evolution of the plasma profiles in tokamak discharges with radiated power close to or equaling the input power. The present work is confined to Ohmic discharges in steady state. It is found that the shape of the density profile can have a significant impact on the variation of the maximum electron density with plasma current. Analytic calculations confirm this result

  19. Transport simulations of a density limit in radiation-dominated tokamak discharges: Profile effects

    International Nuclear Information System (INIS)

    Stotler, D.P.

    1988-06-01

    The density limit observed in tokamak experiments is thought to be due to a radiative collapse of the current channel. A transport code coupled with an MHD equilibrium routine is used to determine the detailed, self-consistent evolution of the plasma profiles in tokamak discharges with radiated power close to or equalling the input power. The present work is confined to ohmic discharges in steady state. It is found that the shape of the density profile can have a significant impact on the variation of the maximum electron density with plasma current. Analytic calculations confirm this result. 41 refs., 9 figs

  20. A state-space modeling approach to estimating canopy conductance and associated uncertainties from sap flux density data.

    Science.gov (United States)

    Bell, David M; Ward, Eric J; Oishi, A Christopher; Oren, Ram; Flikkema, Paul G; Clark, James S

    2015-07-01

    Uncertainties in ecophysiological responses to environment, such as the impact of atmospheric and soil moisture conditions on plant water regulation, limit our ability to estimate key inputs for ecosystem models. Advanced statistical frameworks provide coherent methodologies for relating observed data, such as stem sap flux density, to unobserved processes, such as canopy conductance and transpiration. To address this need, we developed a hierarchical Bayesian State-Space Canopy Conductance (StaCC) model linking canopy conductance and transpiration to tree sap flux density from a 4-year experiment in the North Carolina Piedmont, USA. Our model builds on existing ecophysiological knowledge, but explicitly incorporates uncertainty in canopy conductance, internal tree hydraulics and observation error to improve estimation of canopy conductance responses to atmospheric drought (i.e., vapor pressure deficit), soil drought (i.e., soil moisture) and above canopy light. Our statistical framework not only predicted sap flux observations well, but it also allowed us to simultaneously gap-fill missing data as we made inference on canopy processes, marking a substantial advance over traditional methods. The predicted and observed sap flux data were highly correlated (mean sensor-level Pearson correlation coefficient = 0.88). Variations in canopy conductance and transpiration associated with environmental variation across days to years were many times greater than the variation associated with model uncertainties. Because some variables, such as vapor pressure deficit and soil moisture, were correlated at the scale of days to weeks, canopy conductance responses to individual environmental variables were difficult to interpret in isolation. Still, our results highlight the importance of accounting for uncertainty in models of ecophysiological and ecosystem function where the process of interest, canopy conductance in this case, is not observed directly. The StaCC modeling

  1. Effect of spectrally varying albedo of vegetation surfaces on shortwave radiation fluxes and aerosol direct radiative forcing

    Directory of Open Access Journals (Sweden)

    L. Zhu

    2012-12-01

    Full Text Available This study develops an algorithm for representing detailed spectral features of vegetation albedo based on Moderate Resolution Imaging Spectrometer (MODIS observations at 7 discrete channels, referred to as the MODIS Enhanced Vegetation Albedo (MEVA algorithm. The MEVA algorithm empirically fills spectral gaps around the vegetation red edge near 0.7 μm and vegetation water absorption features at 1.48 and 1.92 μm which cannot be adequately captured by the MODIS 7 channels. We then assess the effects of applying MEVA in comparison to four other traditional approaches to calculate solar fluxes and aerosol direct radiative forcing (DRF at the top of atmosphere (TOA based on the MODIS discrete reflectance bands. By comparing the DRF results obtained through the MEVA method with the results obtained through the other four traditional approaches, we show that filling the spectral gap of the MODIS measurements around 0.7 μm based on the general spectral behavior of healthy green vegetation leads to significant improvement in the instantaneous aerosol DRF at TOA (up to 3.02 W m−2 difference or 48% fraction of the aerosol DRF, −6.28 W m−2, calculated for high spectral resolution surface reflectance from 0.3 to 2.5 μm for deciduous vegetation surface. The corrections of the spectral gaps in the vegetation spectrum in the near infrared, again missed by the MODIS reflectances, also contributes to improving TOA DRF calculations but to a much lower extent (less than 0.27 W m−2, or about 4% of the instantaneous DRF.

    Compared to traditional approaches, MEVA also improves the accuracy of the outgoing solar flux between 0.3 to 2.5 μm at TOA by over 60 W m−2 (for aspen 3 surface and aerosol DRF by over 10 W m−2 (for dry grass. Specifically, for Amazon vegetation types, MEVA can improve the accuracy of daily averaged aerosol radiative forcing in the spectral range of 0.3 to 2.5 μm at

  2. The density of states for the Bi-dimensional Anderson model in the presence of a magnetic field with quantum plaque flux

    International Nuclear Information System (INIS)

    Kuehl, N.M.

    1987-01-01

    The regularity properties of the integrated density of states and the state density of the Anderson bidimensional tight-binding model, in the presence of a uniform magnetic field, perpendicular to the plane of the system by means of quantum flux with plaques, are studied. (A.C.A.S.) [pt

  3. The contribution of accreting black holes to the background radiation density

    International Nuclear Information System (INIS)

    Carr, B.J.

    1979-01-01

    Black holes could generate radiation as a result of accretion. The requirement that this radiation should not have a density exceeding the observed background density places an interesting limit on the number of black holes, depending on the wavelength at which the radiation is generated and the efficiency with which it is produced from accreted material. Consideration of the radiation produced in the present epoch already constrains the mass range in which black holes could have a significant cosmological density. For pregalactic black holes, which may have been accreting more rapidly in the past, the constraint could be even stronger. However, because pregalactic accretion will in general increase the matter temperature of the Universe, it is a self-limiting process. For this reason the pregalactic accretion limit is not as strong as one might naively expect and it is generally weaker than the present epoch limit. (author)

  4. High Density Radiation Shielding Concretes for Hot Cells of 99mTc Project

    International Nuclear Information System (INIS)

    Sakr, K.

    2006-01-01

    High density concrete [more than 3.6 ton/m 3 (3.6x10 3 kg/m 3 )] was prepared to be used as a radiation shielding concrete (RSC) for hot-cells in gel technetium project at inshas to attenuate gamma radiation emitted from radioactive sources. different types of concrete were prepared by mixing local mineral aggregates mainly gravel and ilmenite . iron shots were added to the concrete mixture proportion as partial replacement of heavy aggregates to increase its density. the physical properties of prepared concrete in both plastic and hardened phases were investigated. compressive strength and radiation attenuation of gamma rays were determined. Results showed that ilmenite concrete mixed with iron shots had the highest density suitable to be use as RSC according to the chinese hot cell design requirements. Recommendations to avoid some technical problems of manufacturing radiation shielding concrete were maintained

  5. Electromagnetic radiation generated by arcing in low density plasma

    Science.gov (United States)

    Vayner, Boris V.; Ferguson, Dale C.; Snyder, David B.; Doreswamy, C. V.

    1996-01-01

    An unavoidable step in the process of space exploration is to use high-power, very large spacecraft launched into Earth orbit. Obviously, the spacecraft will need powerful energy sources. Previous experience has shown that electrical discharges occur on the surfaces of a high-voltage array, and these discharges (arcs) are undesirable in many respects. Moreover, any high voltage conductor will interact with the surrounding plasma, and that interaction may result in electrical discharges between the conductor and plasma (or between two conductors with different potentials, for example, during docking and extravehicular activity). One very important aspect is the generation of electromagnetic radiation by arcing. To prevent the negative influence of electromagnetic noise on the operation of spacecraft systems, it seems necessary to determine the spectra and absolute levels of the radiation, and to determine limitations on the solar array bias voltage that depend on the parameters of LEO plasma and the technical requirements of the spacecraft equipment. This report describes the results of an experimental study and computer simulation of the electromagnetic radiation generated by arcing on spacecraft surfaces. A large set of high quality data was obtained during the Solar Array Module Plasma Interaction Experiment (SAMPIE, flight STS-62) and ground test. These data include the amplitudes of current, pulse forms, duration of each arc, and spectra of plasma waves. A theoretical explanation of the observed features is presented in this report too. The elaborated model allows us to determine the parameters of the electromagnetic noise for different frequency ranges, distances from the arcing site, and distinct kinds of plasma waves.

  6. High density flux of Co nanoparticles produced by a simple gas aggregation apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Landi, G. T.; Romero, S. A.; Santos, A. D. [Departamento de Fisica dos Materiais e Mecanica, Laboratorio de Materiais Magneticos, Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05314-970 Sao Paulo, SP (Brazil)

    2010-03-15

    Gas aggregation is a well known method used to produce clusters of different materials with good size control, reduced dispersion, and precise stoichiometry. The cost of these systems is relatively high and they are generally dedicated apparatuses. Furthermore, the usual sample production speed of these systems is not as fast as physical vapor deposition devices posing a problem when thick samples are needed. In this paper we describe the development of a multipurpose gas aggregation system constructed as an adaptation to a magnetron sputtering system. The cost of this adaptation is negligible and its installation and operation are both remarkably simple. The gas flow for flux in the range of 60-130 SCCM (SCCM denotes cubic centimeter per minute at STP) is able to completely collimate all the sputtered material, producing spherical nanoparticles. Co nanoparticles were produced and characterized using electron microscopy techniques and Rutherford back-scattering analysis. The size of the particles is around 10 nm with around 75 nm/min of deposition rate at the center of a Gaussian profile nanoparticle beam.

  7. High density flux of Co nanoparticles produced by a simple gas aggregation apparatus

    International Nuclear Information System (INIS)

    Landi, G. T.; Romero, S. A.; Santos, A. D.

    2010-01-01

    Gas aggregation is a well known method used to produce clusters of different materials with good size control, reduced dispersion, and precise stoichiometry. The cost of these systems is relatively high and they are generally dedicated apparatuses. Furthermore, the usual sample production speed of these systems is not as fast as physical vapor deposition devices posing a problem when thick samples are needed. In this paper we describe the development of a multipurpose gas aggregation system constructed as an adaptation to a magnetron sputtering system. The cost of this adaptation is negligible and its installation and operation are both remarkably simple. The gas flow for flux in the range of 60-130 SCCM (SCCM denotes cubic centimeter per minute at STP) is able to completely collimate all the sputtered material, producing spherical nanoparticles. Co nanoparticles were produced and characterized using electron microscopy techniques and Rutherford back-scattering analysis. The size of the particles is around 10 nm with around 75 nm/min of deposition rate at the center of a Gaussian profile nanoparticle beam.

  8. Extracorporeal shock wave therapy with low-energy flux density inhibits hypertrophic scar formation in an animal model.

    Science.gov (United States)

    Zhao, Jing-Chun; Zhang, Bo-Ru; Hong, Lei; Shi, Kai; Wu, Wei-Wei; Yu, Jia-Ao

    2018-04-01

    Hypertrophic scar is characterized by excessive deposits of collagen during skin wound healing, which could become a challenge to clinicians. This study assessed the effects of the extracorporeal shock wave therapy (ESWT) on hypertrophic scar formation and the underlying gene regu-lation. A rabbit ear hypertrophic scar model was generated and randomly divided into three groups: L-ESWT group to receive L-ESWT (energy flux density of 0.1 mJ/mm2), H-ESWT (energy flux density of 0.2 mJ/mm2) and sham ESWT group (S-ESWT). Hypertrophic scar tissues were then collected and stained with hematoxylin and eosin (H&E) and Masson's trichrome staining, respectively, to assess scar elevation index (SEI), fibroblast density and collagen fiber arrangement. Expression of cell proliferation marker proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin (α-SMA) were assessed using RT-PCR and immunohistochemistry in hypertrophic scar tissues. H&E staining sections showed significant reduction of SEI and fibroblast density in both ESWT treatment groups compared to S-ESWT, but there was no dramatic difference between L-ESWT and H-ESWT groups. Masson's trichrome staining showed that collagen fibers were more slender and broader and oriented in parallel to skin surface after administration of ESWT compared to control tissues. At the gene level, PCNA‑positive fibroblasts and α-SMA-positive myofibroblasts were significantly decreased after L-ESWT or H-ESWT compared to the controls. Furthermore, there was no significant difference in expression of PCNA mRNA between L-ESWT or H-ESWT and S-ESWT, whereas expression of α-SMA mRNA significantly decreased in L-ESWT compared to that of H-ESWT and S-ESWT (P=0.002 and P=0.030, respectively). In conclusion, L-ESWT could be effective on suppression of hypertrophic scar formation by inhibition of scar elevation index and fibroblast density as well as α-SMA expression in hypertrophic scar tissues of the rabbit model.

  9. Top-of-atmosphere radiative fluxes - Validation of ERBE scanner inversion algorithm using Nimbus-7 ERB data

    Science.gov (United States)

    Suttles, John T.; Wielicki, Bruce A.; Vemury, Sastri

    1992-01-01

    The ERBE algorithm is applied to the Nimbus-7 earth radiation budget (ERB) scanner data for June 1979 to analyze the performance of an inversion method in deriving top-of-atmosphere albedos and longwave radiative fluxes. The performance is assessed by comparing ERBE algorithm results with appropriate results derived using the sorting-by-angular-bins (SAB) method, the ERB MATRIX algorithm, and the 'new-cloud ERB' (NCLE) algorithm. Comparisons are made for top-of-atmosphere albedos, longwave fluxes, viewing zenith-angle dependence of derived albedos and longwave fluxes, and cloud fractional coverage. Using the SAB method as a reference, the rms accuracy of monthly average ERBE-derived results are estimated to be 0.0165 (5.6 W/sq m) for albedos (shortwave fluxes) and 3.0 W/sq m for longwave fluxes. The ERBE-derived results were found to depend systematically on the viewing zenith angle, varying from near nadir to near the limb by about 10 percent for albedos and by 6-7 percent for longwave fluxes. Analyses indicated that the ERBE angular models are the most likely source of the systematic angular dependences. Comparison of the ERBE-derived cloud fractions, based on a maximum-likelihood estimation method, with results from the NCLE showed agreement within about 10 percent.

  10. Scanning micro-Hall probe mapping of magnetic flux distributions and current densities in YBa{sub 2}Cu{sub 3}O{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Xing, W.; Heinrich, B. [Simon Fraser Univ., British Columbia (Canada); Zhou, H. [CTF Systems, Inc., British Columbia (Canada)] [and others

    1994-12-31

    Mapping of the magnetic flux density B{sub z} (perpendicular to the film plane) for a YBa{sub 2}Cu{sub 3}O{sub 7} thin-film sample was carried out using a scanning micro-Hall probe. The sheet magnetization and sheet current densities were calculated from the B{sub z} distributions. From the known sheet magnetization, the tangential (B{sub x,y}) and normal components of the flux density B were calculated in the vicinity of the film. It was found that the sheet current density was mostly determined by 2B{sub x,y}/d, where d is the film thickness. The evolution of flux penetration as a function of applied field will be shown.

  11. Relationship of cancer incidence to terrestrial radiation and population density in Connecticut, 1935-1974

    International Nuclear Information System (INIS)

    Walter, S.D.; Meigs, J.W.; Heston, J.F.

    1986-01-01

    The relationship of cancer incidence to terrestrial radiation and population density was investigated. Cancer incidence was obtained using 40 years of age-standardized data from the Connecticut Tumor Registry, and environmental radiation was estimated using data from an airborne gamma radiation survey of the entire state. These variables were examined ecologically, using the 169 towns of the state as the analytic units in a weighted regression analysis. The study design involves a large population base in a state having relatively high terrestrial radiation exposure levels overall and reasonable variation in exposure between towns. For all cancer combined, only one of the eight sex-specific analyses by decade yielded a significant radiation regression coefficient, and this was negative. In the sex- and site-specific analyses, almost all the coefficients for radiation were not significantly different from zero. In contrast, significant positive relationships of cancer incidence with population density were found for all cancer, for cancer of the lung for both sexes, for stomach, colonic, and prostatic cancer for males, and for lymphomas, thyroid, breast, and ovarian cancer for females. Both the radiation and population density relationships were adjusted for socioeconomic status. Socioeconomic status was significantly negatively associated with stomach and lung cancer in males and with cervical cancer in females; it was also positively associated with lymphomas and breast cancer in females. A power calculation revealed that, despite the relatively large size of this study, there was only a small probability of detecting a radiation effect of the strength anticipated from previous estimates

  12. Measurement of the unaccompanied pion-proton flux ratio at 2,900 meters using a transition radiation detector

    International Nuclear Information System (INIS)

    Ellsworth, R.W.; Ito, A.S.; MacFall, J.R.; Siohan, F.; Streitmatter, R.E.; Tonwar, S.C.; Yodh, G.B.

    1975-01-01

    A transition radiation dedector and an ionization calorimeter have been used to measure the unaccompanied pion to proton flux ratio for energies greater than 400 and 600 GeV at an altitude of 2,900 meters. (orig./BJ) [de

  13. High density terahertz frequency comb produced by coherent synchrotron radiation

    Science.gov (United States)

    Tammaro, S.; Pirali, O.; Roy, P.; Lampin, J.-F.; Ducournau, G.; Cuisset, A.; Hindle, F.; Mouret, G.

    2015-07-01

    Frequency combs have enabled significant progress in frequency metrology and high-resolution spectroscopy extending the achievable resolution while increasing the signal-to-noise ratio. In its coherent mode, synchrotron radiation is accepted to provide an intense terahertz continuum covering a wide spectral range from about 0.1 to 1 THz. Using a dedicated heterodyne receiver, we reveal the purely discrete nature of this emission. A phase relationship between the light pulses leads to a powerful frequency comb spanning over one decade in frequency. The comb has a mode spacing of 846 kHz, a linewidth of about 200 Hz, a fractional precision of about 2 × 10-10 and no frequency offset. The unprecedented potential of the comb for high-resolution spectroscopy is demonstrated by the accurate determination of pure rotation transitions of acetonitrile.

  14. The Study of Radio Flux Density Variations of the Quasar OJ 287 by the Wavelet and the Singular Spectrum Methods

    Directory of Open Access Journals (Sweden)

    Donskykh Ganna

    2016-06-01

    Full Text Available Flux density variations of the extragalactic radio source OJ 287 are studied by applying the wavelet and the singular spectrum methods to the long-term monitoring data at 14.5, 8.0 and 4.8 GHz acquired at the University of Michigan Radio Astronomy Observatory during 40 years. This monitoring significantly supplements the episodic VLBI data. The wavelet analysis at all three frequencies revealed the presence of quasiperiods within the intervals 6.0–7.4 and 1.2–1.8 years. The singular spectrum analysis revealed the presence of quasiperiods within the intervals 6–10 and 1.6–4.0 years. For each quasiperiod the time interval of its existence was determined.

  15. Evaluation of the radiation resistance of high-density polyethylene

    International Nuclear Information System (INIS)

    Dougherty, D.R.; Adams, J.W.; Barletta, R.R.

    1984-03-01

    Mechanical tests following gamma irradiation and creep tests during irradiation have been conducted on high-density polyethylene (HDPE) to provide data to help assess the adequacy of this material for use in high integrity containers (HICs). Two types of HDPE, a highly cross-linked rotationally molded material and a non-cross-linked blow molded material, were used in these tests. Gamma-ray irradiations were performed at several dose rates in environments of air, Barnwell and Hanford backfill soils, and ion-exchange resins. The results of tensile and bend tests on these materials following irradiation are presented along with results on creep during irradiation. 8 references, 9 figures, 2 tables

  16. Annihilation Radiation Gauge for Relative Density and Multiphase Fluid Monitoring

    Directory of Open Access Journals (Sweden)

    Vidal A.

    2014-03-01

    Full Text Available The knowledge of the multi-phase flow parameters are important for the petroleum industry, specifically during the transport in pipelines and network related to exploitation’s wells. Crude oil flow is studied by Monte Carlo simulation and experimentally to determine transient liquid phase in a laboratory system. Relative density and fluid phase time variation is monitored employing a fast nuclear data acquisition setup that includes two large volume BaF2 scintillator detectors coupled to an electronic chain and data display in a LabView® environment. Fluid parameters are determined by the difference in count rate of coincidence pulses. The operational characteristics of the equipment indicate that 2 % deviation in the CCR corresponds to a variation, on average, of 20 % in the fraction of liquid of the multiphase fluid.

  17. Transport analysis of high radiation and high density plasmas in the ASDEX Upgrade tokamak

    Directory of Open Access Journals (Sweden)

    Casali L.

    2014-01-01

    Full Text Available Future fusion reactors, foreseen in the “European road map” such as DEMO, will operate under more demanding conditions compared to present devices. They will require high divertor and core radiation by impurity seeding to reduce heat loads on divertor target plates. In addition, DEMO will have to work at high core densities to reach adequate fusion performance. The performance of fusion reactors depends on three essential parameters: temperature, density and energy confinement time. The latter characterizes the loss rate due to both radiation and transport processes. The DEMO foreseen scenarios described above were not investigated so far, but are now addressed at the ASDEX Upgrade tokamak. In this work we present the transport analysis of such scenarios. Plasma with high radiation by impurity seeding: transport analysis taking into account the radiation distribution shows no change in transport during impurity seeding. The observed confinement improvement is an effect of higher pedestal temperatures which extend to the core via stiffness. A non coronal radiation model was developed and compared to the bolometric measurements in order to provide a reliable radiation profile for transport calculations. High density plasmas with pellets: the analysis of kinetic profiles reveals a transient phase at the start of the pellet fuelling due to a slower density build up compared to the temperature decrease. The low particle diffusion can explain the confinement behaviour.

  18. 5th International Congress on Energy Fluxes and Radiation Effects 2016

    International Nuclear Information System (INIS)

    2017-01-01

    Special Issue of the Materials of the V International Congress on Energy Fluxes and Radiation Effects (Tomsk, Russia, 2016)Maksim Trigub, Georgiy Osokin, Alexander KonovodNational Research Tomsk Polytechnic University, 30, Lenin Avenue, Tomsk, Russiaemail: geosokin@tpu.ruThe present issue of the journal is based on the materials of the V International Congress on Energy Fluxes and Radiation Effects 2016 (EFRE 2016) that was held on October 2 to 7, 2016 in Tomsk (Russia). This large scientific forum gathers together scientists, developers and representatives of knowledge-intensive enterprises that have relevance to physics and technology. This year, the Congress was dedicated to the 120 th anniversary of the National Research Tomsk Polytechnic University.The history of the Congress as a joint scientific event dates back to 2000; it traditionally includes three conferences: International Symposium on High-Current Electronics (SHCE), International Conference on Radiation Physics and Chemistry of Condensed Matter (RPC) and International Conference on Modification of Materials with Particle Beams and Plasma Flows (CMM). However, each of these large conferences has its own lasting history.In 2016, the International Symposium on High-Current Electronics was arranged for the 19 th time. The participants have presented the results of fundamental studies and applied outcomes in the fields of high-power pulsed energy engineering and electronics (Pulsed Power), physics and application of high-power electron and ion beams, high- and low-temperature gas discharge plasma, physics of high-energy treatment and extreme states of matter, electric pulsed technologies. Noteworthy, the symposium took place in the year of the 40 th anniversary of USSR scientific discovery of explosive electron emission. This physical phenomenon—being one of the basics of high-current electronics—determines the processes in pulsed vacuum discharge, enables the operation of high-current electron

  19. Neutron flux density and secondary-particle energy spectra at the 184-inch synchrocyclotron medical facility

    International Nuclear Information System (INIS)

    Smith, A.R.; Schimmerling, W.; Henson, A.M.; Kanstein, L.L.; McCaslin, J.B.; Stephens, L.D.; Thomas, R.H.; Ozawa, J.; Yeater, F.W.

    1978-07-01

    Helium ions, with an energy of 920 MeV, produced by the 184-inch synchrocyclotron of the Lawrence Berkeley Laboratory are now being used in a pilot series to determine their efficacy in the treatment of tumors of large volume. The techniques for production of the large uniform radiation fields required for these treatments involve the use of beam-limiting collimators and energy degraders. Interaction of the primary beam with these beam components produces secondary charged particles and neutrons. The sources of neutron production in the beam transport system of the alpha-particle beam have been identified and their magnitudes have been determined. Measurements with activation detectors and pulse counters of differing energy responses have been used to determine secondary particle spectra at various locations on the patient table. These spectra are compared to a calculation of neutron production based on best estimates derived from published cross sections. Agreement between the calculated spectra and those derived from experimental measurements is obtained (at the 10 to 20% level) when the presence of charged particles is taken into account. The adsorbed dose in soft tissue is not very sensitive to the shape of the incident neutron energy spectrum, and the values obtained from unfolding the experimental measurements agree with the values obtained from the calculated spectra within the estimated uncertainty of +-25%. These values are about 3 x 10 -3 rad on the beam axis and about 1 x 10 -3 rad at 20 cm or more from the beam axis, per rad deposited by the incident alpha-particle beam. Estimates of upper limit dose to the lens of the eye and red bone marrow are approximately 10 rad and approximately 1 rad, respectively, for a typical treatment plan. The absorbed dose to the lens of the eye is thus well below the threshold value for cataractogenesis estimated for fission neutrons. An upper limit for the risk of leukemia is estimated to be approximately 0.04%

  20. Numerical research of dynamic characteristics in tower solar cavity receiver based on step-change radiation flux

    Science.gov (United States)

    Chen, Zhengwei; Wang, Yueshe; Hao, Yun; Wang, Qizhi

    2013-07-01

    The solar cavity receiver is an important light-energy to thermal-energy convector in the tower solar thermal power plant system. The heat flux in the inner surface of the cavity will show the characteristics of non-continuous step change especially in non-normal and transient weather conditions, which may result in a continuous dynamic variation of the characteristic parameters. Therefore, the research of dynamic characteristics of the receiver plays a very important role in the operation and the control safely in solar cavity receiver system. In this paper, based on the non-continuous step change of radiation flux, a non-linear dynamic model is put forward to obtain the effects of the non-continuous step change radiation flux and step change feed water flow on the receiver performance by sequential modular approach. The subject investigated in our study is a 1MW solar power station constructed in Yanqing County, Beijing. This study has obtained the dynamic responses of the characteristic parameters in the cavity receiver, such as drum pressure, drum water level, main steam flow and main steam enthalpy under step change radiation flux. And the influence law of step-change feed water flow to the dynamic characteristics in the receiver also has been analyzed. The results have a reference value for the safe operation and the control in solar cavity receiver system.

  1. Flooding Regime Impacts on Radiation, Evapotranspiration, and Latent Energy Fluxes over Groundwater-Dependent Riparian Cottonwood and Saltcedar Forests

    Directory of Open Access Journals (Sweden)

    James Cleverly

    2015-01-01

    Full Text Available Radiation and energy balances are key drivers of ecosystem water and carbon cycling. This study reports on ten years of eddy covariance measurements over groundwater-dependent ecosystems (GDEs in New Mexico, USA, to compare the role of drought and flooding on radiation, water, and energy budgets of forests differing in species composition (native cottonwood versus nonnative saltcedar and flooding regime. After net radiation (700–800 W m−2, latent heat flux was the largest energy flux, with annual values of evapotranspiration exceeding annual precipitation by 250–600%. Evaporative cooling dominated the energy fluxes of both forest types, although cottonwood generated much lower daily values of sensible heat flux (<−5 MJ m−2 d−1. Drought caused a reduction in evaporative cooling, especially in the saltcedar sites where evapotranspiration was also reduced, but without a substantial decline in depth-to-groundwater. Our findings have broad implications on water security and the management of native and nonnative vegetation within semiarid southwestern North America. Specifically, consideration of the energy budgets of GDEs as they respond to fluctuations in climatic conditions can inform the management options for reducing evapotranspiration and maintaining in-stream flow, which is legally mandated as part of interstate and international water resources agreements.

  2. On the secular decrease of radio emission flux densities of the supernova remnants of Cassiopeia A and Taurus A at frequency 927 MHz

    International Nuclear Information System (INIS)

    Vinyajkin, E.N.; Razin, V.A.

    1979-01-01

    Relative measurements of the radio emission flux densities of the supernova remnants of Cassiopeia A and Taurus A were made at the frequency 927 MHz to investigate the secular decrease of their intensity. Experiments were fulfilled in October-December 1977 at the 10-meter radio telescope of the radioastronomical station Staraya Pustyn' (NIRFI). The radio galaxied of Cygnus A, Virgo A and Orion Nebula were taken as the comparison sources. The comparison of the data obtained with the results of absolute measurements carried out in October 1962 permits to state that during 15 years the radio emission flux density of Cassiopeia A decreased by (14.2+-0.6)% (the average annual decrease amounts to (0.95+-O.04)%) and the radio emission flux density of Taurus A decreased by (2.7+-0.1)% (the annual decrease is (0.18+-0.01)%)

  3. Radiation phenomena and particle fluxes in the X-event in JET

    Energy Technology Data Exchange (ETDEWEB)

    Jaeckel, H J; Bartlett, D V; Falter, H; Lingertat, J; Reichle, R [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

    1994-07-01

    The radiation build-up and the particle fluxes in the phase, immediately preceding the X-event, has been studied bolometrically and using spectroscopy. The results show that the H-mode phase in high performance discharges tends to collapse irreversibly. The (calculated) target temperature just before the X-event amounts to about 1400 C. Any deterioration of confinement at this temperature leads to run-away conditions of the target temperature and a final fall-back into L-mode. Possible causes of the confinement deterioration are: MHD activities can cause a fast plasma loss and, hence, a power flash, dumped on the divertor target, leading to a temperature jump of up to 1000 C; enhanced recycling, due to thermal release of trapped deuterium from the graphite target plates causes an effective plasma edge cooling; loose graphite on the target tiles with virtually no thermal coupling to the target bulk can be sublimated and ejected into the main plasma with even small power levels. An active cooling, keeping the bulk target at ambient temperature could make the discharge more resilient against even medium MHD instabilities, as e.g. giant ELMs. 5 refs., 4 figs.

  4. Analytical treatment of the relationships between soil heat flux/net radiation ratio and vegetation indices

    International Nuclear Information System (INIS)

    Kustas, W.P.; Daughtry, C.S.T.; Oevelen, P.J. van

    1993-01-01

    Relationships between leaf area index (LAI) and midday soil heat flux/net radiation ratio (G/R n ) and two more commonly used vegetation indices (VIs) were used to analytically derive formulas describing the relationship between G/R n and VI. Use of VI for estimating G/R n may be useful in operational remote sensing models that evaluate the spatial variation in the surface energy balance over large areas. While previous experimental data have shown that linear equations can adequately describe the relationship between G/Rn and VI, this analytical treatment indicated that nonlinear relationships are more appropriate. Data over bare soil and soybeans under a range of canopy cover conditions from a humid climate and data collected over bare soil, alfalfa, and cotton fields in an arid climate were used to evaluate model formulations derived for LAI and G/R n , LAI and VI, and VI and G/R n . In general, equations describing LAI-G/R n and LAI-VI relationships agreed with the data and supported the analytical result of a nonlinear relationship between VI and G/R n . With the simple ratio (NIR/Red) as the VI, the nonlinear relationship with G/R n was confirmed qualitatively. But with the normalized difference vegetation index (NDVI), a nonlinear relationship did not appear to fit the data. (author)

  5. ECF2: A pulsed power generator based on magnetic flux compression for K-shell radiation production

    International Nuclear Information System (INIS)

    L'Eplattenier, P.; Lassalle, F.; Mangeant, C.; Hamann, F.; Bavay, M.; Bayol, F.; Huet, D.; Morell, A.; Monjaux, P.; Avrillaud, G.; Lalle, B.

    2002-01-01

    The 3 MJ energy stored ECF2 generator is developed at Centre d'Etudes de Gramat, France, for K-shell radiation production. This generator is based on microsecond LTD stages as primary generators, and on the magnetic flux compression scheme for power amplification from the microsecond to the 100ns regime. This paper presents a general overview of the ECF2 generator. The flux compression stage, a key component, will be studied in details. We will present its advantages and drawbacks. We will then present the first experimental and numerical results which show the improvements that have already been made on this scheme

  6. Low radiation dose impact on human bone mineral density

    International Nuclear Information System (INIS)

    Zaichick, V.E.

    2002-01-01

    osteoporosis in two groups of cleaners different from each other by the level of external total body irradiation (up to 10 cSv and between 11 and 25 cSv) was about the same. This fact shows no significant effect of factor 1 with a radiation dose of not more than 25 cSv. The highest incidence of osteopenia and osteoporosis (78 %) was found in the group of cleaners working in Chernobyl in 1986 that may be related to the action of factors 2 and 3. Because the group of exposed men who were studied was selected randomly, it can be concluded that even by 2002 more than 50 % of the cleaners still had clear changes in the mineral component of the skeleton. Because about 300,000 young Russian men were involved in the Chernobyl NPP cleanup operation, the resulting medical problem is of great social importance. Neither effective preventive measures not treatment is practicable without the basic etiological factors of osteoporosis in the young adult cleaners. Modern methods make it possible to perform precise studies of endocrine and immune status, to assess of water-electrolyte, mineral, and trace element metabolism, and estimate retrospectively the levels of intoxication from Pb and Cd. Unfortunately, during the past 16 years, neither national nor international sources have been found to finance such studies

  7. Determining the temperature and density distribution from a Z-pinch radiation source

    International Nuclear Information System (INIS)

    Matuska, W.; Lee, H.

    1997-01-01

    High temperature radiation sources exceeding one hundred eV can be produced via z-pinches using currently available pulsed power. The usual approach to compare the z-pinch simulation and experimental data is to convert the radiation output at the source, whose temperature and density distributions are computed from the 2-D MHD code, into simulated data such as a spectrometer reading. This conversion process involves a radiation transfer calculation through the axially symmetric source, assuming local thermodynamic equilibrium (LTE), and folding the radiation that reaches the detector with the frequency-dependent response function. In this paper the authors propose a different approach by which they can determine the temperature and density distributions of the radiation source directly from the spatially resolved spectral data. This unfolding process is reliable and unambiguous for the ideal case where LTE holds and the source is axially symmetric. In reality, imperfect LTE and axial symmetry will introduce inaccuracies into the unfolded distributions. The authors use a parameter optimization routine to find the temperature and density distributions that best fit the data. They know from their past experience that the radiation source resulting from the implosion of a thin foil does not exhibit good axial symmetry. However, recent experiments carried out at Sandia National Laboratory using multiple wire arrays were very promising to achieve reasonably good symmetry. For these experiments the method will provide a valuable diagnostic tool

  8. Relating Radiative Fluxes on Arctic Sea Ice Area Using Arctic Observation and Reanalysis Integrated System (ArORIS)

    Science.gov (United States)

    Sledd, A.; L'Ecuyer, T. S.

    2017-12-01

    With Arctic sea ice declining rapidly and Arctic temperatures rising faster than the rest of the globe, a better understanding of the Arctic climate, and ice cover-radiation feedbacks in particular, is needed. Here we present the Arctic Observation and Reanalysis Integrated System (ArORIS), a dataset of integrated products to facilitate studying the Arctic using satellite, reanalysis, and in-situ datasets. The data include cloud properties, radiative fluxes, aerosols, meteorology, precipitation, and surface properties, to name just a few. Each dataset has uniform grid-spacing, time-averaging and naming conventions for ease of use between products. One intended use of ArORIS is to assess Arctic radiation and moisture budgets. Following that goal, we use observations from ArORIS - CERES-EBAF radiative fluxes and NSIDC sea ice fraction and area to quantify relationships between the Arctic energy balance and surface properties. We find a discernable difference between energy budgets for years with high and low September sea ice areas. Surface fluxes are especially responsive to the September sea ice minimum in months both leading up to September and the months following. In particular, longwave fluxes at the surface show increased sensitivity in the months preceding September. Using a single-layer model of solar radiation we also investigate the individual responses of surface and planetary albedos to changes in sea ice area. By partitioning the planetary albedo into surface and atmospheric contributions, we find that the atmospheric contribution to planetary albedo is less sensitive to changes in sea ice area than the surface contribution. Further comparisons between observations and reanalyses can be made using the available datasets in ArORIS.

  9. Physics of radiation-driven islands near the tokamak density limit

    International Nuclear Information System (INIS)

    Gates, D.A.; Delgado-Aparicio, L.; White, R.B.

    2013-01-01

    In previous work (Gates and Delgado-Aparicio 2012 Phys. Rev. Lett. 108 165004), the onset criterion for radiation-driven islands (Rebut et al 1985 Proc. 10th Int. Conf. on Plasma Physics and Controlled Nuclear Fusion Research 1984 (London, UK, 1984) vol 2 (Vienna: IAEA) p 197) in combination with a simple cylindrical model of tokamak current channel behaviour was shown to be consistent with the empirical scaling of the tokamak density limit (Greenwald et al 1988 Nucl. Fusion 28 2199). A number of the unexplained phenomena at the density limit are consistent with this novel physics mechanism. In this work, a more formal theoretical underpinning, consistent with cylindrical tearing mode theory, is developed for the onset criteria of these modes. The appropriate derivation of the radiation-driven addition to the modified Rutherford equation (MRE) is discussed. Additionally, the ordering of the terms in the MRE is examined in a regime near the density limit. It is hoped that, given the apparent success of this simple model in explaining the observed global scalings, it will lead to a more comprehensive analysis of the possibility that radiation-driven islands are the physics mechanism responsible for the density limit. In particular, with modern diagnostic capabilities detailed measurements of current densities, electron densities and impurity concentrations at rational surfaces should be possible, enabling verification of the concepts described above. (paper)

  10. Dispersive effects in radiation transport and radiation hydrodynamics in matter at high density

    International Nuclear Information System (INIS)

    Crowley, B.J.B.

    1983-01-01

    In a recent research program (reported in AWRE 0 20/82) I have investigated the generalisation of the equations of radiation hydrodynamics when electromagnetic radiation is assumed to obey a linear-response dispersion relation of the form nω=kc where the refractive index n depends on the frequency ω and/or wave number k. From the application of the Boltzmann-Liouville transport theory to photons in the short-wavelength (geometrical optics) limit, I derive the energy and momentum equations which, when combined with a classical (Euler-Lagrange-Navier-Stokes) treatment of a fluid material medium in LTE, yield a complete dynamical theory of linear interactions (+ stimulated processes) between incoherent (thermal) radiation and dense, locally isotropic matter. The theory includes an account of pondero-motive forces and electro (magneto) striction. Moreover, it is apparently capable of being generalised to non-linear interactions in which the refractive index depends on the local specific intensity of the radiation field, and, to some extent, to the treatment of high-frequency coherent radiation. The generalisation of various approximated forms of radiation-transport theory (esp. diffusion) has been considered in detail. Some problems remain however. One such is the treatment of anomalous dispersion. Current research work is concentrating on the interesting atomic physics aspects of electromagnetic (esp. radiative) properties of a dispersive material medium

  11. A novel approach to calculate inductance and analyze magnetic flux density of helical toroidal coil applicable to Superconducting Magnetic Energy Storage systems (SMES)

    International Nuclear Information System (INIS)

    Alizadeh Pahlavani, M.R.; Shoulaie, A.

    2010-01-01

    In this paper, formulas are proposed for the self and mutual inductance calculations of the helical toroidal coil (HTC) by the direct and indirect methods at superconductivity conditions. The direct method is based on the Neumann's equation and the indirect approach is based on the toroidal and the poloidal components of the magnetic flux density. Numerical calculations show that the direct method is more accurate than the indirect approach at the expense of its longer computational time. Implementation of some engineering assumptions in the indirect method is shown to reduce the computational time without loss of accuracy. Comparison between the experimental measurements and simulated results for inductance, using the direct and the indirect methods indicates that the proposed formulas have high reliability. It is also shown that the self inductance and the mutual inductance could be calculated in the same way, provided that the radius of curvature is >0.4 of the minor radius, and that the definition of the geometric mean radius in the superconductivity conditions is used. Plotting contours for the magnetic flux density and the inductance show that the inductance formulas of helical toroidal coil could be used as the basis for coil optimal design. Optimization target functions such as maximization of the ratio of stored magnetic energy with respect to the volume of the toroid or the conductor's mass, the elimination or the balance of stress in some coordinate directions, and the attenuation of leakage flux could be considered. The finite element (FE) approach is employed to present an algorithm to study the three-dimensional leakage flux distribution pattern of the coil and to draw the magnetic flux density lines of the HTC. The presented algorithm, due to its simplicity in analysis and ease of implementation of the non-symmetrical and three-dimensional objects, is advantageous to the commercial software such as ANSYS, MAXWELL, and FLUX. Finally, using the

  12. Wide Dynamic Range Multiband Infrared Radiometer for In-Fire Measurements of Wildland Fire Radiant Flux Density

    Science.gov (United States)

    Kremens, R.; Dickinson, M. B.; Hardy, C.; Skowronski, N.; Ellicott, E. A.; Schroeder, W.

    2016-12-01

    We have developed a wide dynamic range (24-bit) data acquisition system for collection of radiant flux density (FRFD) data from wildland fires. The data collection subsystem was designed as an Arduino `shield' and incorporates a 24-bit analog-to-digital converter, precision voltage reference, real time clock, microSD card interface, audible annuciator and interface for various digital communication interfaces (RS232, I2C, SPI, etc.). The complete radiometer system consists of our custom-designed `shield', a commercially available Arduino MEGA computer circuit board and a thermopile sensor -amplifier daughter board. Software design and development is greatly assisted by the availability of a library of public-domain, user-implemented software. The daughter board houses a 5-band radiometer using thermopiles designed for this experiment (Dexter Research Corp., Dexter, MI) to allow determination of the total FRFD from the fire (using a wide band thermopile with a KRS-5 window, 0.1 - 30 um), the FRFD as would be received by an orbital asset like MODIS (3.95 um center wavelength (CWL) and 10.95 CWL, corresponding to MODIS bands 21/22 and 31, respectively) and wider bandpass (0.1-5.5 um and 8-14 um) corresponding to the FRFD recorded by `MWIR' and `LWIR' imaging systems. We required a very wide dynamic range system in order to be able to record the flux density from `cold' ground before the fire, through the `hot' flaming combustion stage, to the `cool' phase after passage of the fire front. The recording dynamic range required (with reasonable resolution at the lowest temperatures) is on the order of 106, which is not currently available in commercial instrumentation at a price point, size or feature set that is suitable for wildland fire investigations. The entire unit, along with rechargeable battery power supply is housed in a fireproof aluminum chassis box, which is then mounted on a mast at a height of 5 - 7 m above the fireground floor. We will report initial

  13. Density measurement by means of once scattered gamma radiation the ETG probe, principles and equipment

    International Nuclear Information System (INIS)

    Joergensen, J.L.; Oelgaard, P.L.; Berg, F.

    1987-01-01

    The Department of Electrophysics, the Technical University of Denmark, and the Danish National Road Laboratory have together developed a new patent claimed device for measurements of the in situ density of materials. This report describes the principles of the system and some experimental results. The system is based on the once scattered gamma radiation. In a totally non-destructive and fast way it is possible to measure the density of up to 25 cm thick layers. Furthermore, an estimate of the density variation through the layer may be obtained. Thus the gauge represents a new generation of equipment for e.g. compaction control of road constructions. (author)

  14. Validation of Vegetation Index Time Series from Suomi NPP Visible Infrared Imaging Radiometer Suite Using Tower Radiation Flux Measurements

    Science.gov (United States)

    Miura, T.; Kato, A.; Wang, J.; Vargas, M.; Lindquist, M.

    2015-12-01

    Satellite vegetation index (VI) time series data serve as an important means to monitor and characterize seasonal changes of terrestrial vegetation and their interannual variability. It is, therefore, critical to ensure quality of such VI products and one method of validating VI product quality is cross-comparison with in situ flux tower measurements. In this study, we evaluated the quality of VI time series derived from Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (NPP) spacecraft by cross-comparison with in situ radiation flux measurements at select flux tower sites over North America and Europe. VIIRS is a new polar-orbiting satellite sensor series, slated to replace National Oceanic and Atmospheric Administration's Advanced Very High Resolution Radiometer in the afternoon overpass and to continue the highly-calibrated data streams initiated with Moderate Resolution Imaging Spectrometer of National Aeronautics and Space Administration's Earth Observing System. The selected sites covered a wide range of biomes, including croplands, grasslands, evergreen needle forest, woody savanna, and open shrublands. The two VIIRS indices of the Top-of-Atmosphere (TOA) Normalized Difference Vegetation Index (NDVI) and the atmospherically-corrected, Top-of-Canopy (TOC) Enhanced Vegetation Index (EVI) (daily, 375 m spatial resolution) were compared against the TOC NDVI and a two-band version of EVI (EVI2) calculated from tower radiation flux measurements, respectively. VIIRS and Tower VI time series showed comparable seasonal profiles across biomes with statistically significant correlations (> 0.60; p-value 0.95), with mean differences of 2.3 days and 5.0 days for the NDVI and the EVI, respectively. These results indicate that VIIRS VI time series can capture seasonal evolution of vegetated land surface as good as in situ radiometric measurements. Future studies that address biophysical or physiological interpretations

  15. Nonlinear radiated MHD flow of nanoliquids due to a rotating disk with irregular heat source and heat flux condition

    Science.gov (United States)

    Mahanthesh, B.; Gireesha, B. J.; Shehzad, S. A.; Rauf, A.; Kumar, P. B. Sampath

    2018-05-01

    This research is made to visualize the nonlinear radiated flow of hydromagnetic nano-fluid induced due to rotation of the disk. The considered nano-fluid is a mixture of water and Ti6Al4V or AA7072 nano-particles. The various shapes of nanoparticles like lamina, column, sphere, tetrahedron and hexahedron are chosen in the analysis. The irregular heat source and nonlinear radiative terms are accounted in the law of energy. We used the heat flux condition instead of constant surface temperature condition. Heat flux condition is more relativistic and according to physical nature of the problem. The problem is made dimensionless with the help of suitable similarity constraints. The Runge-Kutta-Fehlberg scheme is adopted to find the numerical solutions of governing nonlinear ordinary differential systems. The solutions are plotted by considering the various values of emerging physical constraints. The effects of various shapes of nanoparticles are drawn and discussed.

  16. Effect of the geometrical parameters of an optical integrator on the unformity of the radiation flux distribution

    International Nuclear Information System (INIS)

    Vishnyakova, T.P.; Klychev, Sh.I.

    1992-01-01

    The use of optical mixers in the optical irradiators of simulators of direct and concentrated solar radiation has been proposed. In this paper, the parameters of an optical mixer are calculated geometrically, and the effect of the parameters of the optical mixer on the unformity of the irradiance distribution η of the radiation flux on the detector is investigated. These investigations show that the light distribution from an optical mixer is close to the characteristics of an ideal uniform emitter within the region from 0 to the limit of α. 5 refs., 4 figs

  17. Are radiative corrections to the Mikheyev-Smirnov-Wolfenstein formula affected by finite temperature and density?

    International Nuclear Information System (INIS)

    Horvat, R.

    1993-01-01

    One-loop photonic corrections to the electron-neutrino (ν e ) charged-current medium induced self-energy are examined using finite temperature field theory. It is shown that irrespective of computing radiative corrections at finite temperature and density, there are no O(α) corrections to the charged-current contribution of the ν e 's dispersion relation

  18. Interaction of laser radiation with a low-density structured absorber

    Czech Academy of Sciences Publication Activity Database

    Rozanov, V. B.; Barishpol’tsev, D.V.; Vergunova, G.A.; Demchenko, N. N.; Ivanov, E.M.; Aristova, E.N.; Zmitrenko, N.V.; Limpouch, I.; Ullschmied, Jiří

    2016-01-01

    Roč. 122, č. 2 (2016), s. 256-276 ISSN 1063-7761 Institutional support: RVO:61389021 Keywords : laser radiation interaction * laser with low-density Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.196, year: 2016

  19. Spatial and Temporal Variabilities of Solar and Longwave Radiation Fluxes below a Coniferous Forest in the French Alps

    Science.gov (United States)

    Sicart, J. E.; Ramseyer, V.; Lejeune, Y.; Essery, R.; Webster, C.; Rutter, N.

    2017-12-01

    At high altitudes and latitudes, snow has a large influence on hydrological processes. Large fractions of these regions are covered by forests, which have a strong influence on snow accumulation and melting processes. Trees absorb a large part of the incoming shortwave radiation and this heat load is mostly dissipated as longwave radiation. Trees shelter the snow surface from wind, so sub-canopy snowmelt depends mainly on the radiative fluxes: vegetation attenuates the transmission of shortwave radiation but enhances longwave irradiance to the surface. An array of 13 pyranometers and 11 pyrgeometers was deployed on the snow surface below a coniferous forest at the CEN-MeteoFrance Col de Porte station in the French Alps (1325 m asl) during the 2017 winter in order to investigate spatial and temporal variabilities of solar and infrared irradiances in different meteorological conditions. Sky view factors measured with hemispherical photographs at each radiometer location were in a narrow range from 0.2 to 0.3. The temperature of the vegetation was measured with IR thermocouples and an IR camera. In clear sky conditions, the attenuation of solar radiation by the canopy reached 96% and its spatial variability exceeded 100 W m-2. Longwave irradiance varied by 30 W m-2 from dense canopy to gap areas. In overcast conditions, the spatial variabilities of solar and infrared irradiances were reduced and remained closely related to the sky view factor. A simple radiative model taking into account the penetration through the canopy of the direct and diffuse solar radiation, and isotropic infrared emission of the vegetation as a blackbody emitter, accurately reproduced the dynamics of the radiation fluxes at the snow surface. Model results show that solar transmissivity of the canopy in overcast conditions is an excellent proxy of the sky view factor and the emitting temperature of the vegetation remained close to the air temperature in this typically dense Alpine forest.

  20. Effects of radiation and high heat flux on the performance of first-wall components. Final report

    International Nuclear Information System (INIS)

    Wolfer, W.G.

    1985-10-01

    The performance of high-heat-flux components in present and future fusion devices is strongly affected by materials properties and their changes with radiation exposure and helium content. In addition, plasma disruptions and thermal fatigue are major life-limiting aspects. A multidisciplinary approach is therefore required in the performance analysis, and the following results have been accomplished. An equation of state for helium has been derived and applied to helium bubble formation by various growth processes. Models for various radiation effects have been developed and perfected to analyze radiation-induced swelling and embrittlement for high-heat flux materials. Computer codes have been developed to predict melting, evaporation, and melt-layer stability during plasma disruptions. A structural analysis code was perfected to evaluate the stress distribution and crack propagation in a high-heat-flux component or first wall. This code was applied to a duplex structure consisting of a beryllium coating on a copper substrate. It was also used to compare the lifetimes of a first wall in a tokamak reactor made of ferritic or austenitic steel

  1. Simulation of Field Dependence of Critical Current Densities of Bulk High Tc Superconducting Materials regarding Thermally Activated Flux Motion

    Science.gov (United States)

    Santosh, M.; Naik, S. Pavan Kumar; Koblischka, M. R.

    2017-07-01

    In the upcoming generation, bulk high temperature superconductors (HTS) will play a crucial and a promising role in numerous industrial applications ranging from Maglev trains to magnetic resonance imaging, etc. Especially, the bulk HTS as permanent magnets are suitable due to the fact that they can trap magnetic fields being several orders of magnitude higher than those of the best hard ferromagnets. The bulk HTS LREBa2Cu3O7-δ (LREBCO or LRE-123, LRE: Y, Gd, etc.,) materials could obtain very powerful compact superconducting super-magnets, which can be operated at the cheaper liquid nitrogen temperature or below due to higher critical temperatures (i.e., ∼90 K). As a result, the new advanced technology can be utilized in a more attractive manner for a variety of technological and medical applications which have the capacity to revolutionize the field. An understanding of the magnetic field dependence of the critical current density (J c(H)) is important to develop better adapted materials. To achieve this goal, a variety of Jc (H) behaviours of bulk LREBCO samples were modelled regarding thermally activated flux motion. In essence, the Jc (H) curves follows a certain criterion where an exponential model is applied. However, to fit the complete Jc (H) curve of the LRE-123 samples an unique model is necessary to explain the behavior at low and high fields. The modelling of the various superconducting materials could be understood in terms of the pinning mechanisms.

  2. Real-time visualization of magnetic flux densities for transcranial magnetic stimulation on commodity and fully immersive VR systems

    Science.gov (United States)

    Kalivarapu, Vijay K.; Serrate, Ciro; Hadimani, Ravi L.

    2017-05-01

    Transcranial Magnetic Stimulation (TMS) is a non-invasive procedure that uses time varying short pulses of magnetic fields to stimulate nerve cells in the brain. In this method, a magnetic field generator ("TMS coil") produces small electric fields in the region of the brain via electromagnetic induction. This technique can be used to excite or inhibit firing of neurons, which can then be used for treatment of various neurological disorders such as Parkinson's disease, stroke, migraine, and depression. It is however challenging to focus the induced electric field from TMS coils to smaller regions of the brain. Since electric and magnetic fields are governed by laws of electromagnetism, it is possible to numerically simulate and visualize these fields to accurately determine the site of maximum stimulation and also to develop TMS coils that can focus the fields on the targeted regions. However, current software to compute and visualize these fields are not real-time and can work for only one position/orientation of TMS coil, severely limiting their usage. This paper describes the development of an application that computes magnetic flux densities (h-fields) and visualizes their distribution for different TMS coil position/orientations in real-time using GPU shaders. The application is developed for desktop, commodity VR (HTC Vive), and fully immersive VR CAVETM systems, for use by researchers, scientists, and medical professionals to quickly and effectively view the distribution of h-fields from MRI brain scans.

  3. The epoxy resin variation effect on microstructure and physical properties to improve bonded NdFeB flux magnetic density

    International Nuclear Information System (INIS)

    Rusnaeni, N.; Sarjono, Priyo; Muljadi; Noer, Nasrudin

    2016-01-01

    NdFeB magnets have been fabricated from a mixture of powder NdFeB (MPQ-B+) and epoxy resins (ER) with a variation of 0% wt, 2% wt, 4% wt and 6% wt. The pellets samples were made by pressing 4 tons of the mixture powder at room temperature before curing at 100°C for 1 hour. The SEM-EDX results showed the microstructure with ER were evenly smeared the NdFeB magnetic particles due to higher percent C and lower transition metals value. Sample with 2% wt epoxy resin was able to achieve the highest density of 5.35 g/cm 3 and the highest magnetic flux of 2121 Gauss. The magnetic properties characterization using the permagraph indicates that the sample pellets with 2% wt epoxy resin has a value of remanence (Br) = 4.92 kG, coercivity (Hc) = 7.76 kOe, and energy product (Bhmax) = 4.58 MGOe. Despite low remanence value in the pellet samples, the resistance to demagnetization value was still acceptable. (paper)

  4. The epoxy resin variation effect on microstructure and physical properties to improve bonded NdFeB flux magnetic density

    Science.gov (United States)

    Rusnaeni, N.; Sarjono, Priyo; Muljadi; Noer, Nasrudin

    2016-11-01

    NdFeB magnets have been fabricated from a mixture of powder NdFeB (MPQ-B+) and epoxy resins (ER) with a variation of 0% wt, 2% wt, 4% wt and 6% wt. The pellets samples were made by pressing 4 tons of the mixture powder at room temperature before curing at 100°C for 1 hour. The SEM-EDX results showed the microstructure with ER were evenly smeared the NdFeB magnetic particles due to higher percent C and lower transition metals value. Sample with 2% wt epoxy resin was able to achieve the highest density of 5.35 g/cm3 and the highest magnetic flux of 2121 Gauss. The magnetic properties characterization using the permagraph indicates that the sample pellets with 2% wt epoxy resin has a value of remanence (Br) = 4.92 kG, coercivity (Hc) = 7.76 kOe, and energy product (Bhmax) = 4.58 MGOe. Despite low remanence value in the pellet samples, the resistance to demagnetization value was still acceptable.

  5. Neutron metrology in the L.F.R. Neutron flux density spectrum in the inner graphite reflector of the L.F.R

    International Nuclear Information System (INIS)

    Zsolnay, E.M.

    1979-01-01

    The neutron spectrum in the vertical central plug of the Low Flux Reactor has been determined experimentally. Sets of activation and fission detectors have been irradiated, and the neutron spectrum has been unfolded with aid of 3 special computer programs SAND-II, RFSP-JUEL and CRYSTAL BALL. Using these 3 programs calculations are made on the improvement ratio, which is defined as the ratio of the variance of the input flux density to that of the output flux density. A Monte Carlo error analysis is made to examine the quality of the 3 solution spectra. The results obtained with the different computer codes were compared, and showed a general agreement. The experiment confirmed that the shape of the spectrum in the intermediate energy region is near the 1/E pattern. (author)

  6. Monitoring of mass flux of catalyst FCC in a Cold Pilot Unit by gamma radiation transmission

    International Nuclear Information System (INIS)

    Brito, Marcio Fernando Paixao de

    2014-01-01

    This paper proposes a model for monitoring the mass flow of catalyst FCC - Fluid Catalytic Cracking - in a CPU - Cold Pilot unit - due to the injection of air and solid by gamma radiation transmission. The CPU simplifies the process of FCC, which is represented by the catalyst cycle, and it was constructed of acrylic, so that the flow can be visualized. The CPU consists of riser separation chamber and return column, and simulates the riser reactor of the FCC process. The catalyst is injected into the column back to the base of the riser, an inclined tube, where the compressed air means that there fluidization along the riser. When the catalyst comes in the separation chamber, the solid phase is sent to the return column, and the gas phase exits the system through one of the four cyclones at the top of the separation chamber. The transmission gamma of measures will be made by means of three test sections that have source and detector shielded. Pressure drop in the riser measurements are made through three pressure gauges positioned on the riser. The source used was Am-241 gamma ray with energy of 60 keV, and detector used was a scintillator of NaI (Tl) of 2 x 2 . Measures the mass flow of catalyst are made by varying the seal of the catalyst, and density of solid in the riser because with the combination of these measures can determine the speed of the catalyst in the riser. The results show that the transmission gamma is a suitable technique for monitoring the flow of catalyst, flow model in CPU is annular, tomography third generation is more appropriate to study the CPU and the density variation in circulation in the CPU decreases linearly with increasing air flow. (author)

  7. User's guide for SLWDN9, a code for calculating flux-surfaced-averaging of alpha densities, currents, and heating in non-circular tokamaks

    International Nuclear Information System (INIS)

    Hively, L.M.; Miley, G.M.

    1980-03-01

    The code calculates flux-surfaced-averaged values of alpha density, current, and electron/ion heating profiles in realistic, non-circular tokamak plasmas. The code is written in FORTRAN and execute on the CRAY-1 machine at the Magnetic Fusion Energy Computer Center

  8. Measurement and Modeling of Vertically Resolved Aerosol Optical Properties and Radiative Fluxes Over the ARM SGP Site

    Science.gov (United States)

    Schmid, B.; Arnott, P.; Bucholtz, A.; Colarco, P.; Covert, D.; Eilers, J.; Elleman, R.; Ferrare, R.; Flagan, R.; Jonsson, H.

    2003-01-01

    In order to meet one of its goals - to relate observations of radiative fluxes and radiances to the atmospheric composition - the Department of Energy's Atmospheric Radiation Measurement (ARM) program has pursued measurements and modeling activities that attempt to determine how aerosols impact atmospheric radiative transfer, both directly and indirectly. However, significant discrepancies between aerosol properties measured in situ or remotely remain. One of the objectives of the Aerosol Intensive Operational Period (TOP) conducted by ARM in May 2003 at the ARM Southern Great Plains (SGP) site in north central Oklahoma was to examine and hopefully reduce these differences. The IOP involved airborne measurements from two airplanes over the heavily instrumented SGP site. We give an overview of airborne results obtained aboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft. The Twin Otter performed 16 research flights over the SGP site. The aircraft carried instrumentation to perform in-situ measurements of aerosol absorption, scattering, extinction and particle size. This included such novel techniques as the photoacoustic and cavity ring-down methods for in-situ absorption (675 nm) and extinction (675 and 1550 nm) and a new multiwavelength, filter-based absorption photometer (467, 530, 660 nm). A newly developed instrument measured cloud condensation nucleus concentration (CCN) concentrations at two supersaturation levels. Aerosol optical depth and extinction (354-2139 nm) were measured with the NASA Ames Airborne Tracking 14-channel sunphotometer. Furthermore, up-and downwelling solar (broadband and spectral) and infrared radiation were measured using seven individual radiometers. Three up-looking radiometers werer mounted on a newly developed stabilized platform, keeping the instruments level up to aircraft pitch and roll angles of approximately 10(exp 0). This resulted in unprecedented continuous vertical profiles

  9. Deterministic Role of Collision Cascade Density in Radiation Defect Dynamics in Si

    Science.gov (United States)

    Wallace, J. B.; Aji, L. B. Bayu; Shao, L.; Kucheyev, S. O.

    2018-05-01

    The formation of stable radiation damage in solids often proceeds via complex dynamic annealing (DA) processes, involving point defect migration and interaction. The dependence of DA on irradiation conditions remains poorly understood even for Si. Here, we use a pulsed ion beam method to study defect interaction dynamics in Si bombarded in the temperature range from ˜-30 ° C to 210 °C with ions in a wide range of masses, from Ne to Xe, creating collision cascades with different densities. We demonstrate that the complexity of the influence of irradiation conditions on defect dynamics can be reduced to a deterministic effect of a single parameter, the average cascade density, calculated by taking into account the fractal nature of collision cascades. For each ion species, the DA rate exhibits two well-defined Arrhenius regions where different DA mechanisms dominate. These two regions intersect at a critical temperature, which depends linearly on the cascade density. The low-temperature DA regime is characterized by an activation energy of ˜0.1 eV , independent of the cascade density. The high-temperature regime, however, exhibits a change in the dominant DA process for cascade densities above ˜0.04 at.%, evidenced by an increase in the activation energy. These results clearly demonstrate a crucial role of the collision cascade density and can be used to predict radiation defect dynamics in Si.

  10. Unconventional application of the two-flux approximation for the calculation of the Ambartsumyan-Chandrasekhar function and the angular spectrum of the backward-scattered radiation for a semi-infinite isotropically scattering medium

    Science.gov (United States)

    Remizovich, V. S.

    2010-06-01

    It is commonly accepted that the Schwarzschild-Schuster two-flux approximation (1905, 1914) can be employed only for the calculation of the energy characteristics of the radiation field (energy density and energy flux density) and cannot be used to characterize the angular distribution of radiation field. However, such an inference is not valid. In several cases, one can calculate the radiation intensity inside matter and the reflected radiation with the aid of this simplest approximation in the transport theory. In this work, we use the results of the simplest one-parameter variant of the two-flux approximation to calculate the angular distribution (reflection function) of the radiation reflected by a semi-infinite isotropically scattering dissipative medium when a relatively broad beam is incident on the medium at an arbitrary angle relative to the surface. We do not employ the invariance principle and demonstrate that the reflection function exhibits the multiplicative property. It can be represented as a product of three functions: the reflection function corresponding to the single scattering and two identical h functions, which have the same physical meaning as the Ambartsumyan-Chandrasekhar function ( H) has. This circumstance allows a relatively easy derivation of simple analytical expressions for the H function, total reflectance, and reflection function. We can easily determine the relative contribution of the true single scattering in the photon backscattering at an arbitrary probability of photon survival Λ. We compare all of the parameters of the backscattered radiation with the data resulting from the calculations using the exact theory of Ambartsumyan, Chandrasekhar, et al., which was developed decades after the two-flux approximation. Thus, we avoid the application of fine mathematical methods (the Wiener-Hopf method, the Case method of singular functions, etc.) and obtain simple analytical expressions for the parameters of the scattered radiation

  11. Plant lighting system with five wavelength-band light-emitting diodes providing photon flux density and mixing ratio control

    Directory of Open Access Journals (Sweden)

    Yano Akira

    2012-11-01

    Full Text Available Abstract Background Plant growth and development depend on the availability of light. Lighting systems therefore play crucial roles in plant studies. Recent advancements of light-emitting diode (LED technologies provide abundant opportunities to study various plant light responses. The LED merits include solidity, longevity, small element volume, radiant flux controllability, and monochromaticity. To apply these merits in plant light response studies, a lighting system must provide precisely controlled light spectra that are useful for inducing various plant responses. Results We have developed a plant lighting system that irradiated a 0.18 m2 area with a highly uniform distribution of photon flux density (PFD. The average photosynthetic PFD (PPFD in the irradiated area was 438 micro-mol m–2 s–1 (coefficient of variation 9.6%, which is appropriate for growing leafy vegetables. The irradiated light includes violet, blue, orange-red, red, and far-red wavelength bands created by LEDs of five types. The PFD and mixing ratio of the five wavelength-band lights are controllable using a computer and drive circuits. The phototropic response of oat coleoptiles was investigated to evaluate plant sensitivity to the light control quality of the lighting system. Oat coleoptiles irradiated for 23 h with a uniformly distributed spectral PFD (SPFD of 1 micro-mol m–2 s–1 nm–1 at every peak wavelength (405, 460, 630, 660, and 735 nm grew almost straight upwards. When they were irradiated with an SPFD gradient of blue light (460 nm peak wavelength, the coleoptiles showed a phototropic curvature in the direction of the greater SPFD of blue light. The greater SPFD gradient induced the greater curvature of coleoptiles. The relation between the phototropic curvature (deg and the blue-light SPFD gradient (micro-mol m–2 s–1 nm–1 m–1 was 2 deg per 1 micro-mol m–2 s–1 nm–1 m–1. Conclusions The plant lighting system, with a computer with a

  12. Sensitivity of modelled sulfate aerosol and its radiative effect on climate to ocean DMS concentration and air–sea flux

    Directory of Open Access Journals (Sweden)

    J.-E. Tesdal

    2016-09-01

    Full Text Available Dimethylsulfide (DMS is a well-known marine trace gas that is emitted from the ocean and subsequently oxidizes to sulfate in the atmosphere. Sulfate aerosols in the atmosphere have direct and indirect effects on the amount of solar radiation reaching the Earth's surface. Thus, as a potential source of sulfate, ocean efflux of DMS needs to be accounted for in climate studies. Seawater concentration of DMS is highly variable in space and time, which in turn leads to high spatial and temporal variability in ocean DMS emissions. Because of sparse sampling (in both space and time, large uncertainties remain regarding ocean DMS concentration. In this study, we use an atmospheric general circulation model with explicit aerosol chemistry (CanAM4.1 and several climatologies of surface ocean DMS concentration to assess uncertainties about the climate impact of ocean DMS efflux. Despite substantial variation in the spatial pattern and seasonal evolution of simulated DMS fluxes, the global-mean radiative effect of sulfate is approximately linearly proportional to the global-mean surface flux of DMS; the spatial and temporal distribution of ocean DMS efflux has only a minor effect on the global radiation budget. The effect of the spatial structure, however, generates statistically significant changes in the global-mean concentrations of some aerosol species. The effect of seasonality on the net radiative effect is larger than that of spatial distribution and is significant at global scale.

  13. Effect of Varieties and Plant Population Densities on Dry Matter Production, Radiation Interception and Radiation Energy Conversion in Peanut

    Directory of Open Access Journals (Sweden)

    agus suprapto

    2012-05-01

    Full Text Available The solar radiation is one of the major criteria to obtaining advantages on peanuts (Arachishypogaea L.. Although various combinations of crops have been reported, but variety association and plant population densities (PPD during the periodically stage of growth on peanuts have yet to be analyzed. Dry matter production (DM, radiation energy interception, and radiation energy conversions were monitored over the growth period of two varieties of peanut. An experiment was conducted in Jambegede Research Farm, Indonesian Legume and Tuber Crops Research Institute, Malang, East Java, Indonesia, from July until October 2011. The experiment was arranged in a Split Plot Design with three replications. Peanut varieties, as the main plot consisted of two treatments: Kelinci andKancil variety. In addition, five PPD variations as sub plot consisted of 8.1, 11.1, 16.0, 25.0 and 44.4 plant m-2 were arranged in a square spacing. The results showed that DM production from high PPD increased gradually to lower PPD in all varieties. Interception efficiency (IE increased in all varieties from early sowing. A plant population density of 25.0 m-2 and 44.4 plants m-2 intercepted more radiation over 11.1 or 16.0 plants m-2. Conversion efficiency of radiation energy (CE to total dry matter production on Kelinci variety (1.52% indicated a slight higher percentage than on Kancil variety (1.41%. Moreover, the CE and IE values indicated a decrease as the PPD increased on maximum DM.

  14. Relations between radiation fluxes of a greenhouse in semi-arid conditions

    International Nuclear Information System (INIS)

    Al-Riahi, M.; Al-Karaghouli, A.; Hasson, A.M.; Al-Kayssi, A.W.

    1989-01-01

    Measurements of global radiation, reflected radiation and net total radiation inside and outside the greenhouse were conducted in Fudhiliyah Agrometeorological Research Station during the period from 1 January to 30 April, 1987. From these measurements, several relationships were established. Linear regressions of hourly values of global radiation inside the greenhouse on hourly global radiation outside the greenhouse were fitted for each month of the recording period. The degree of fit was generally good (r > 0.95). Net short-wave radiation inside the greenhouse showed strong dependence on the global inside radiation (r = 0.998), also the net total radiation and global radiation inside the greenhouse correlate very strongly. From the above-mentioned relationships, it was found that the global, net short-wave and net total radiation could be successfully predicted when only global outside radiation is available. Using the linear regression equations correlating the above radiation parameters, albedo and heating coefficient were derived. Albedo showed strong dependence on solar altitude angle and period of day (forenoon and afternoon). Heating coefficients were consistently positive and their values varied between 0.10 and 0.393. Monthly average values of mean hourly night-time net long-wave radiation inside the greenhouse were −31, −32, −38 and −42 W m −2 for the months of January, February, March and April, respectively

  15. Radiative flux and forcing parameterization error in aerosol-free clear skies.

    Science.gov (United States)

    Pincus, Robert; Mlawer, Eli J; Oreopoulos, Lazaros; Ackerman, Andrew S; Baek, Sunghye; Brath, Manfred; Buehler, Stefan A; Cady-Pereira, Karen E; Cole, Jason N S; Dufresne, Jean-Louis; Kelley, Maxwell; Li, Jiangnan; Manners, James; Paynter, David J; Roehrig, Romain; Sekiguchi, Miho; Schwarzkopf, Daniel M

    2015-07-16

    Radiation parameterizations in GCMs are more accurate than their predecessorsErrors in estimates of 4 ×CO 2 forcing are large, especially for solar radiationErrors depend on atmospheric state, so global mean error is unknown.

  16. Influence of soft ferromagnetic sections on the magnetic flux density profile of a large grain, bulk Y–Ba–Cu–O superconductor

    International Nuclear Information System (INIS)

    Philippe, M P; Wéra, L; Fagnard, J-F; Vanderheyden, B; Vanderbemden, P; Ainslie, M D; Dennis, A R; Shi, Y-H; Cardwell, D A

    2015-01-01

    Bulk, high temperature superconductors have significant potential for use as powerful permanent magnets in a variety of practical applications due to their ability to trap record magnetic fields. In this paper, soft ferromagnetic sections are combined with a bulk, large grain Y–Ba–Cu–O high temperature superconductor to form superconductor/ferromagnet hybrid structures. We study how the ferromagnetic sections influence the shape of the profile of the trapped magnetic induction at the surface of each structure and report the surface magnetic flux density measured by Hall probe mapping. These configurations have been modelled using a 2D axisymmetric finite element method based on the H-formulation and the results show excellent qualitative and quantitative agreement with the experimental measurements. The model has also been used to study the magnetic flux distribution and predict the behaviour for other constitutive laws and geometries. The results show that the ferromagnetic material acts as a magnetic shield, but the flux density and its gradient are enhanced on the face opposite to the ferromagnet. The thickness and saturation magnetization of the ferromagnetic material are important and a characteristic ferromagnet thickness d* is derived: below d*, saturation of the ferromagnet occurs, and above d*, a weak thickness-dependence is observed. The influence of the ferromagnet is observed even if its saturation magnetization is lower than the trapped flux density of the superconductor. Conversely, thin ferromagnetic discs can be driven to full saturation even though the outer magnetic field is much smaller than their saturation magnetization. (paper)

  17. Interaction between the radiative flux emitted by a corium melt and aerosols from corium/concrete interaction

    Energy Technology Data Exchange (ETDEWEB)

    Zabiego, M.; Cognet, G. [CEA-DRN/DER/SERA - CE Cadarache, Saint-Paul-Lez-Durance (France); Henderson, D. [Univ. of Wisconsin, Madison, WI (United States)

    1995-09-01

    In this paper we present a one-dimensional numerical model that deals with radiative transfer in a medium where aerosols are present. This model is written with the aim of performing radiative transfer calculations in the framework of severe Pressurized Water Reactor accidents, especially during the last stage of such an accident Molten Core Concrete Interaction (MCCI) when aerosols are very numerous. We explain the theoretical basis of our model, writing the general radiative transfer equation, knowing that aerosol droplets participate in radiation transport. We then simplify this equation for a one-dimensional medium and we propose to solve it using the spherical harmonics approximation. This gives us the radiative intensity and we can then deduce the radiative flux. Aerosol optical properties (extinction and scattering coefficients) are also required in such a calculation. They are determined using Rayleigh or Mie theory, depending, depending on the aerosol size. In order to provide an example of results one can expect from such a calculation, we applied our model to a test problem with given aerosol size and concentration distributions. Our example does not model any experiment explicitly but the physical conditions used are very close to the L4 test from the Advanced Containment Experiment (ACE) program.

  18. Heavy density concrete for nuclear radiation shielding and power stations: [Part]3

    International Nuclear Information System (INIS)

    Singha Roy, P.K.

    1987-01-01

    This article is the third part of the paper entitled 'Heavy density concrete for nuclear radiation shielding and power stations'. Specific considerations relevant to natural but manufactured heavy aggregates like haematite used in India are briefly discussed. They include water-cement ratio, strength versus water-cement ratio, mix design strength and aggregate grading. Some typical mix proportions in haematite concretes used in India are given. Equipment for heavy density concrete is mentioned. Quality control methods and tests for heavy density concrete are described under the heading: type and chemical composition of the rock, specific gravity and surface absorption of the aggregates, grading of aggregates, cement, batching, mixing, compressive strength, and density. Construction aspects such as form work, placement, vibration, finishing, and temperature control are discussed. Finally it is pointed out that for optimising the design and economy of heavy density concrete, it is necessary to carry out country-wide survey of suitable materials, to study their properties, suitability and effectiveness in shielding radiation. (M.G.B.)

  19. A unifying probabilistic Bayesian approach to derive electron density from MRI for radiation therapy treatment planning

    International Nuclear Information System (INIS)

    Gudur, Madhu Sudhan Reddy; Hara, Wendy; Le, Quynh-Thu; Wang, Lei; Xing, Lei; Li, Ruijiang

    2014-01-01

    MRI significantly improves the accuracy and reliability of target delineation in radiation therapy for certain tumors due to its superior soft tissue contrast compared to CT. A treatment planning process with MRI as the sole imaging modality will eliminate systematic CT/MRI co-registration errors, reduce cost and radiation exposure, and simplify clinical workflow. However, MRI lacks the key electron density information necessary for accurate dose calculation and generating reference images for patient setup. The purpose of this work is to develop a unifying method to derive electron density from standard T1-weighted MRI. We propose to combine both intensity and geometry information into a unifying probabilistic Bayesian framework for electron density mapping. For each voxel, we compute two conditional probability density functions (PDFs) of electron density given its: (1) T1-weighted MRI intensity, and (2) geometry in a reference anatomy, obtained by deformable image registration between the MRI of the atlas and test patient. The two conditional PDFs containing intensity and geometry information are combined into a unifying posterior PDF, whose mean value corresponds to the optimal electron density value under the mean-square error criterion. We evaluated the algorithm’s accuracy of electron density mapping and its ability to detect bone in the head for eight patients, using an additional patient as the atlas or template. Mean absolute HU error between the estimated and true CT, as well as receiver operating characteristics for bone detection (HU > 200) were calculated. The performance was compared with a global intensity approach based on T1 and no density correction (set whole head to water). The proposed technique significantly reduced the errors in electron density estimation, with a mean absolute HU error of 126, compared with 139 for deformable registration (p = 2  ×  10 −4 ), 283 for the intensity approach (p = 2  ×  10 −6 ) and 282

  20. Study and application of high-density concrete in radiation-shielding experiment

    International Nuclear Information System (INIS)

    Wu Chongming; Ding Dexin; Xiao Xuefu; Wang Shaolin; Lin Xingjun; Shen Yuanyuan

    2008-01-01

    According to the demand for research and construction project, a series of systematic experiments and studies on shielding γ-ray radiation concrete with the density of 4.60 t/m 3 were made in such aspects as mix ratio design, construction technology, uniformly shielding etc. Such issues as uniformity in the construction and compactness were solved. The ray test method for uniformly shielding concrete was presented and some technical steps for this high-density concrete used in the process of test design or construction were summed up. A series of tests and practical applications show that this technology of mix ratio design and construction is feasible. (authors)

  1. Method of measuring surface density

    International Nuclear Information System (INIS)

    Gregor, J.

    1982-01-01

    A method is described of measuring surface density or thickness, preferably of coating layers, using radiation emitted by a suitable radionuclide, e.g., 241 Am. The radiation impinges on the measured material, e.g., a copper foil and in dependence on its surface density or thickness part of the flux of impinging radiation is reflected and part penetrates through the material. The radiation which has penetrated through the material excites in a replaceable adjustable backing characteristic radiation of an energy close to that of the impinging radiation (within +-30 keV). Part of the flux of the characteristic radiation spreads back to the detector, penetrates through the material in which in dependence on surface density or thickness of the coating layer it is partly absorbed. The flux of the penetrated characteristic radiation impinging on the face of the detector is a function of surface density or thickness. Only that part of the energy is evaluated of the energy spectrum which corresponds to the energy of characteristic radiation. (B.S.)

  2. Fast pyrobolometers for measurements of plasma heat fluxes and radiation losses in the MST Reversed Field Pinch

    International Nuclear Information System (INIS)

    Fiksel, G.; Frank, J.; Holly, D.

    1993-01-01

    Two types of fast bolometers are described for the plasma energy transport study in the Madison Symmetric Torus plasma confinement device. Both types use pyrocrystals of LiTaO 3 or LiNbO 3 as the sensors. One type is used for measurements of the radiated heat losses and is situated at the vacuum shell inner surface. Another type is insertable in the plasma and measures the plasma particle heat flux. The frequency response of the bolometers is measured to be in the 150--200 kHz range. The range of the measured power fluxes is 0.1 W/cm 2 10 kW/cm 2 and can be adjusted by changing the size of the entrance aperture. The lower limit is determined by the amplifier noise and the frequency bandwidth, the higher limit by destruction of the bolometer sensor

  3. Types of Lightning Discharges that Abruptly Terminate Enhanced Fluxes of Energetic Radiation and Particles Observed at Ground Level

    International Nuclear Information System (INIS)

    Chilingarian, A.; Khanikyants, Y.; Pokhsraryan, D.; Soghomonyan, S.; Mareev, E.; Rakov, V.

    2017-01-01

    We present ground-based measurements of thunderstorm-related enhancements of fluxes of energetic radiation and particles that are abruptly terminated by lightning discharges. All measurements were performed at an altitude of 3200 m above sea level on Mt. Aragats (Armenia). Lightning signatures were recorded using a network of five electric field mills, three of which were placed at the Aragats station, one at the Nor Amberd station (12.8 km from Aragats), and one at the Yerevan station (39 km from Aragats), and a wideband electric field measuring system with a useful frequency bandwidth of 50 Hz to 12 MHZ. It appears that the flux-enhancement termination is associated with close (within 10 km or so of the particle detector) -CGs and normal polarity ICs; that is, with lightning types which reduce the upward-directed electric field below the cloud and, hence, suppress the acceleration of electrons toward the ground. (author)

  4. Energy exchanges in a Central Business District - Interpretation of Eddy Covariance and radiation flux measurements (London UK)

    Science.gov (United States)

    Kotthaus, S.; Grimmond, S.

    2013-12-01

    Global urbanisation brings increasingly dense and complex urban structures. To manage cities sustainably and smartly, currently and into the future under changing climates, urban climate research needs to advance in areas such as Central Business Districts (CBD) where human interactions with the environment are particularly concentrated. Measurement and modelling approaches may be pushed to their limits in dense urban settings, but if urban climate research is to contribute to the challenges of real cities those limits have to be addressed. The climate of cities is strongly governed by surface-atmosphere exchanges of energy, moisture and momentum. Observations of the relevant fluxes provide important information for improvement and evaluation of modelling approaches. Due to the CBD's heterogeneity, a very careful analysis of observations is required to understand the relevant processes. Current approaches used to interpret observations and set them in a wider context may need to be adapted for use in these more complex areas. Here, we present long-term observations of the radiation balance components and turbulent fluxes of latent heat, sensible heat and momentum in the city centre of London. This is one of the first measurement studies in a CBD covering multiple years with analysis at temporal scales from days to seasons. Data gathered at two sites in close vicinity, but with different measurement heights, are analysed to investigate the influence of source area characteristics on long-term radiation and turbulent fluxes. Challenges of source area modelling and the critical aspect of siting in such a complex environment are considered. Outgoing long- and short-wave radiation are impacted by the anisotropic nature of the urban surface and the high reflectance materials increasingly being used as building materials. Results highlight the need to consider the source area of radiometers in terms of diffuse and direct irradiance. Sensible heat fluxes (QH) are positive

  5. Comparison of Radiation Dose Rates with the Flux to Dose Conversion Factors Recommended in ICRP-74 and ICRP-116

    International Nuclear Information System (INIS)

    Jeong, Hae Sun; Kil, A Reum; Lee, Jo Eun; Jeong, Hyo Joon; Kim, Eun Han; Han, Moon Hee; Hwang, Won Tae

    2016-01-01

    The evaluation of radiation shielding has been performed for the design and maintenance of various facilities using radioactive sources such as nuclear fuel, accelerator, and radionuclide. The conversion of flux to dose mainly used in nuclear and radiation fields has been generally made with the dose coefficients presented in ICRP Publication 74 (ICRP- 74), which are produced based on ICRP Publication 60. On the other hand, ICRP Publication 116 (ICRP-116), which adopts the protection system of ICRP Publication 103, has recently been published and provides the dose conversion coefficients calculated with a variety of Monte Carlo codes. The coefficients have more than an update of those in ICRP-74, including new particle types and a greatly expanded energy range. In this study, a shielding evaluation of a specific container for neutron and gamma sources was performed with the MCNP6 code. The dose rates from neutron and gamma-ray sources were calculated using the MCNP6 codes, and these results were based on the flux to dose conversion factors recommended in ICRP-74 and ICRP-116. As a result, the dose rates evaluated with ICRP-74 were generally shown higher than those with ICRP-116. For neutrons, the difference is mainly occurred by the decrease of radiation weighting factors in a part of energy ranges in the ICRP-116 recommendations. For gamma-rays, the ICRP-74 recommendation applied with the kerma approximation leads to overestimated results than the other assessment

  6. Two-dimensional AXUV-based radiated power density diagnostics on NSTX-U.

    Science.gov (United States)

    Faust, I; Delgado-Aparicio, L; Bell, R E; Tritz, K; Diallo, A; Gerhardt, S P; LeBlanc, B; Kozub, T A; Parker, R R; Stratton, B C

    2014-11-01

    A new set of radiated-power-density diagnostics for the National Spherical Torus Experiment Upgrade (NSTX-U) tokamak have been designed to measure the two-dimensional poloidal structure of the total photon emissivity profile in order to perform power balance, impurity transport, and magnetohydrodynamic studies. Multiple AXUV-diode based pinhole cameras will be installed in the same toroidal angle at various poloidal locations. The local emissivity will be obtained from several types of tomographic reconstructions. The layout and response expected for the new radially viewing poloidal arrays will be shown for different impurity concentrations to characterize the diagnostic sensitivity. The radiated power profile inverted from the array data will also be used for estimates of power losses during transitions from various divertor configurations in NSTX-U. The effect of in-out and top/bottom asymmetries in the core radiation from high-Z impurities will be addressed.

  7. Two-dimensional AXUV-based radiated power density diagnostics on NSTX-Ua)

    Science.gov (United States)

    Faust, I.; Delgado-Aparicio, L.; Bell, R. E.; Tritz, K.; Diallo, A.; Gerhardt, S. P.; LeBlanc, B.; Kozub, T. A.; Parker, R. R.; Stratton, B. C.

    2014-11-01

    A new set of radiated-power-density diagnostics for the National Spherical Torus Experiment Upgrade (NSTX-U) tokamak have been designed to measure the two-dimensional poloidal structure of the total photon emissivity profile in order to perform power balance, impurity transport, and magnetohydrodynamic studies. Multiple AXUV-diode based pinhole cameras will be installed in the same toroidal angle at various poloidal locations. The local emissivity will be obtained from several types of tomographic reconstructions. The layout and response expected for the new radially viewing poloidal arrays will be shown for different impurity concentrations to characterize the diagnostic sensitivity. The radiated power profile inverted from the array data will also be used for estimates of power losses during transitions from various divertor configurations in NSTX-U. The effect of in-out and top/bottom asymmetries in the core radiation from high-Z impurities will be addressed.

  8. Two-dimensional AXUV-based radiated power density diagnostics on NSTX-U

    Energy Technology Data Exchange (ETDEWEB)

    Faust, I.; Parker, R. R. [MIT - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Delgado-Aparicio, L.; Bell, R. E.; Diallo, A.; Gerhardt, S. P.; LeBlanc, B.; Kozub, T. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Tritz, K. [The Johns Hopkins University, Baltimore, Maryland 21209 (United States); Stratton, B. C. [MIT - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States)

    2014-11-15

    A new set of radiated-power-density diagnostics for the National Spherical Torus Experiment Upgrade (NSTX-U) tokamak have been designed to measure the two-dimensional poloidal structure of the total photon emissivity profile in order to perform power balance, impurity transport, and magnetohydrodynamic studies. Multiple AXUV-diode based pinhole cameras will be installed in the same toroidal angle at various poloidal locations. The local emissivity will be obtained from several types of tomographic reconstructions. The layout and response expected for the new radially viewing poloidal arrays will be shown for different impurity concentrations to characterize the diagnostic sensitivity. The radiated power profile inverted from the array data will also be used for estimates of power losses during transitions from various divertor configurations in NSTX-U. The effect of in-out and top/bottom asymmetries in the core radiation from high-Z impurities will be addressed.

  9. Two-dimensional AXUV-based radiated power density diagnostics on NSTX-U

    International Nuclear Information System (INIS)

    Faust, I.; Parker, R. R.; Delgado-Aparicio, L.; Bell, R. E.; Diallo, A.; Gerhardt, S. P.; LeBlanc, B.; Kozub, T. A.; Tritz, K.; Stratton, B. C.

    2014-01-01

    A new set of radiated-power-density diagnostics for the National Spherical Torus Experiment Upgrade (NSTX-U) tokamak have been designed to measure the two-dimensional poloidal structure of the total photon emissivity profile in order to perform power balance, impurity transport, and magnetohydrodynamic studies. Multiple AXUV-diode based pinhole cameras will be installed in the same toroidal angle at various poloidal locations. The local emissivity will be obtained from several types of tomographic reconstructions. The layout and response expected for the new radially viewing poloidal arrays will be shown for different impurity concentrations to characterize the diagnostic sensitivity. The radiated power profile inverted from the array data will also be used for estimates of power losses during transitions from various divertor configurations in NSTX-U. The effect of in-out and top/bottom asymmetries in the core radiation from high-Z impurities will be addressed

  10. Analysis of waste compounds of Gauzama Crinita and high density PET reinforced by gamma radiation

    International Nuclear Information System (INIS)

    Gago, Javier; Ramos, Victor; Hernandez, Yuri; Montoya, Eduardo; Lopez, Alcides; Universidad Nacional de Ingenieria, Lima; Acevedo, Moises

    2013-01-01

    The reinforcing effects of gamma radiation in a high density polyethylene and wood waste white Bolaina (Guazuma crinita) compounds from Pucallpa region are presented. Samples were mixed with maleic anhydride and extruded at a temperature between 170 and 200 °C, yielding small cylindrical pellets; were subsequently pressed through thermic process between 180 and 200 °C, in a time range between 15 to 20 minutes. The produced samples were exposed to gamma radiation between 50 and 300 kGy, and then subjected to mechanical testing of hardness and roughness. It was observed that the hardness and the roughness increases in direct proportion to the increase of the dose of gamma radiation, but the samples subjected to doses in the range of 100 to 150 kGy, had a slight inverse behavior. (authors).

  11. Gamma radiation effects on the rheological properties of high and low density polyethylenes

    International Nuclear Information System (INIS)

    Rangel-Nafaile, C.; Garcia-Rejon, A.; Garcia Leon, A.

    1986-01-01

    High energy radiation of polymeric materials is a topic of considerable interest from commercial and scientific points of view. Within an inert atmosphere, irradiation of polyethylene yields a crosslinking effect with a consequent improvement in its mechanical properties in comparison to the virgin materials. Additionally, if irradiated specimens are melted and recrystallized, the radiation-induced crosslinking hinders their crystalline growth altering dramatically their flow properties such as the elasticity. This work portrays the effects of the gamma radiation on the rheological properties of high and low density polyethylenes manufactured by PEMEX and analyzes the implications of theoretical results derived from the Acierno's model when it is implemented with the rheological properties of high energy irradiated polyethylenes. (author)

  12. Influence of Laser Radiation Power Density on the Intensity of Spectral Lines for Main Components in a Clay Laser-Induced Plasma

    Science.gov (United States)

    Anufrik, S. S.; Kurian, N. N.; Znosko, K. F.; Belkov, M. V.

    2018-05-01

    We have studied the intensity of the spectral lines for the main components in clay: Al I 309.4 nm, Al II 358.7 nm, Mg II 279.6 nm, Ti II 323.6 nm vs. the position of the object relative to the focus of the optical system when the samples are exposed to single laser pulses from a YAG:Nd3+ laser. We have determined the permissible ranges for positioning the object relative to the focus of the optical system (positive and negative defocusing) for which there is practically no change in the reproducibility of the intensity for the spectral lines for red and white clay samples. We show that the position of the object relative to the focus of the optical system should be within the range ΔZ ±1.5 mm for optimal laser pulse energies for the analyte spectral lines. We have calculated the radiation flux density for different laser pulse energies and different distances from the focus to the object. We have shown experimentally that reducing the radiation flux density leads to a decrease in the intensity of the analyte spectral lines.

  13. Radiative corrections for the direct detection of neutralino dark matter and its relic density

    Energy Technology Data Exchange (ETDEWEB)

    Steppeler, Patrick Norbert

    2016-07-01

    entering the Boltzmann equation in many scenarios of the MSSM. The Boltzmann equation allows to determine the neutralino relic density, i.e. to predict their present abundance. This prediction can be checked experimentally and is thus of great phenomenological relevance. Measurements of the temperature fluctuations of the cosmic microwave background permit to determine the relic density precisely. Comparing the theoretical prediction with the experimental finding allows to exclude large fractions of the MSSM parameter space. In order to maximally benefit from the experimental precision, it is necessary to minimise theoretical uncertainties and to include the aforementioned radiative corrections. The radiative corrections to the elastic neutralino-nucleon scattering and the corresponding relic density have been implemented into the numerical package Dark matter at next-to-leading order. With the help of this program, we perform a phenomenological investigation and analyse the impact of the radiative corrections. It turns out that the neutralino relic density depends not on a single but a multitude of gaugino (co)annihilation processes in parallel quite often. The calculated radiative corrections lead to a relative shift of the relic density of up to 10%, which is significantly larger than the experimental uncertainty (±2% at the 1σ confidence level) and demonstrates that these corrections should be included when identifying the cosmologically preferred region of the MSSM. Moreover, we investigate the relation between the relic density and the neutralino-nucleon cross sections. In the spin-independent case, the inclusion of radiative corrections leads to a relative shift roughly +14% in comparison to a tree-level calculation. This shift is comparable to typical recent nuclear uncertainties, which influence the prediction as well. The spin-dependent cross section is subject to even larger shifts and modified by up to -50% by radiative corrections.

  14. FLUXNET: A new tool to study the temporal and spatial variability of ecosystem-scale carbon dioxide, water vapor, and energy flux densities

    DEFF Research Database (Denmark)

    Baldocchi, D.; Falge, E.; Gu, L.

    2001-01-01

    FLUXNET is a global network of micrometeorological flux measurement site's that measure the exchanges of carbon dioxide, water vapor, and energy between the biosphere and atmosphere. At present over 140 sites are operating on a long-term and continuous basis. Vegetation under study includes...... of annual ecosystem carbon and water balances, to quantify the response of stand-scale carbon dioxide and water vapor flux densities to controlling biotic and abiotic factors, and to validate a hierarchy of soil-plant-atmosphere trace gas exchange models. Findings so far include 1) net CO2 exchange......, it provides infrastructure for compiling, archiving, and distributing carbon, water, and energy flux measurement, and meteorological, plant, and soil data to the science community. (Data and site information are available online at the FLUXNET Web site, http://www-eosdis.oml.gov/FLUXNTET/.) Second...

  15. Small compression modulus of the flux line lattice and large density fluctuations at high fields may explain peak effect

    International Nuclear Information System (INIS)

    Brandt, E.H.

    1976-01-01

    The elastic properties of the flux line lattice in Type II superconductors as calculated from the Ginsburg-Landau theory are discussed. They are non-local on a length scale much larger than the flux line distance and divergent at Hsub(c2). The compression modulus may become much smaller than its long-wavelength limit, B 2 /4π, and if the deformation is not homogeneous, at Hsub(c2) the modulus vanishes as (Hsub(c2) - B) 2 . At arbitrary induction the compression modulus of strain waves with wavelengths of several flux line distances is of the order of the (small) shear modulus. (author)

  16. Heavy density concrete for nuclear radiation shielding and power stations: [Part]2

    International Nuclear Information System (INIS)

    Singha Roy, P.K.

    1987-01-01

    This article is the second part of the paper entitled 'Heavy density concrete for nuclear radiation shielding and power stations'. In this part, some of the important properties of heavy density concrete are discussed. They include density, water retentivity, air content, permeability with special reference to concrete mixes used in India's nuclear power reactors. All these properties are affected to various extents by heating. Indian shield concrete is rarely subjected to temperatures above 60degC during its life, because of thermal shield protection. During placement, the maximum anticipated rise in temperature due to heat of hydration is restricted to around 45degC by chilling, if necessary to reduce shrinkage stresses and cracks. (M.G.B.)

  17. Temperature and carrier-density dependence of Auger and radiative recombination in nitride optoelectronic devices

    International Nuclear Information System (INIS)

    Kioupakis, Emmanouil; Yan, Qimin; Steiauf, Daniel; Van de Walle, Chris G

    2013-01-01

    Nitride light-emitting diodes are a promising solution for efficient solid-state lighting, but their performance at high power is affected by the efficiency-droop problem. Previous experimental and theoretical work has identified Auger recombination, a three-particle nonradiative carrier recombination mechanism, as the likely cause of the droop. In this work, we use first-principles calculations to elucidate the dependence of the radiative and Auger recombination rates on temperature, carrier density and quantum-well confinement. Our calculated data for the temperature dependence of the recombination coefficients are in good agreement with experiment and provide further validation on the role of Auger recombination in the efficiency reduction. Polarization fields and phase-space filling negatively impact device efficiency because they increase the operating carrier density at a given current density and increase the fraction of carriers lost to Auger recombination. (paper)

  18. Measurement of the Lyman-alpha radiation at ionization manometers for determination of the hydrogen atom number density in fusion experiments

    International Nuclear Information System (INIS)

    Loercher, M.

    1990-01-01

    Codes like DEGAS which simulate the interaction of neutral gas with plasma (e.g. in a divertor), not only deliver the global density and flux of neutral particles, but also allow one, in addition, to distinguish between atoms and molecules. Whereas the global parameters of the neutral gas in a divertor can be measured by, for example, special ion gauges like those, which are installed in the divertor chamber, there has until now been no possibility of measuring the atomic and molecular density independently. In the frame of a diploma thesis (M. Loercher) an ASDEX neutral pressure gauge was modified in such a way that it delivers not only the global density of neutral particles (molecules and atoms) by ionization, but also the density of the atoms by measurement of the Lα-radiation produced by electron impact exitation. Owing to the very weak intensity the main effort was dedicated to developing a detector-filter combination which allows the Lα-radiation to be separated from, the H 2 bands in the VUV and be measured with a time resolution of at least of few ms. Several versions were tested theoretically and practically. The best solution was found to be a combination of an O 2 filter using MgF 2 windows and a multichannel plate. The arrangement was tested and calibrated with an atomic beam of known intensity from an oven. (orig.)

  19. Two new methods used to simulate the circumferential solar flux density concentrated on the absorber of a parabolic trough solar collector

    Science.gov (United States)

    Guo, Minghuan; Wang, Zhifeng; Sun, Feihu

    2016-05-01

    The optical efficiencies of a solar trough concentrator are important to the whole thermal performance of the solar collector, and the outer surface of the tube absorber is a key interface of energy flux. So it is necessary to simulate and analyze the concentrated solar flux density distributions on the tube absorber of a parabolic trough solar collector for various sun beam incident angles, with main optical errors considered. Since the solar trough concentrators are linear focusing, it is much of interest to investigate the solar flux density distribution on the cross-section profile of the tube absorber, rather than the flux density distribution along the focal line direction. Although a few integral approaches based on the "solar cone" concept were developed to compute the concentrated flux density for some simple trough concentrator geometries, all those integral approaches needed special integration routines, meanwhile, the optical parameters and geometrical properties of collectors also couldn't be changed conveniently. Flexible Monte Carlo ray trace (MCRT) methods are widely used to simulate the more accurate concentrated flux density distribution for compound parabolic solar trough concentrators, while generally they are quite time consuming. In this paper, we first mainly introduce a new backward ray tracing (BRT) method combined with the lumped effective solar cone, to simulate the cross-section flux density on the region of interest of the tube absorber. For BRT, bundles of rays are launched at absorber-surface points of interest, directly go through the glass cover of the absorber, strike on the uniformly sampled mirror segment centers in the close-related surface region of the parabolic reflector, and then direct to the effective solar cone around the incident sun beam direction after the virtual backward reflection. All the optical errors are convoluted into the effective solar cone. The brightness distribution of the effective solar cone is supposed

  20. Critical current density, irreversibility line, and flux creep activation energy in silver-sheathed Bi2Sr2Ca2Cu3Ox superconducting tapes

    International Nuclear Information System (INIS)

    Shi, D.; Wang, Z.; Sengupta, S.; Smith, M.; Goodrich, L.F.; Dou, S.X.; Liu, H.K.; Guo, Y.C.

    1992-08-01

    Transport data, magnetic hysteresis and flux creep activation energy experimental results are presented for silver-sheathed high-T c Bi 2 Sr 2 Ca 2 Cu 3 O x superconducting tapes. The 110 K superconducting phase was formed by lead doping in a Bi-Sr-Ca-Cu-0 system. The transport critical current density was measured at 4.0 K to be 0.7 x 10 5 A/cm 2 (the corresponding critical current is 74 A) at zero field and 1.6 x 10 4 A/cm 2 at 12 T for H parallel ab. Excellent grain alignment in the a-b plane was achieved by a short-melting method, which considerably improved the critical current density and irreversibility line. Flux creep activation energy as a function of current is obtained based on the magnetic relaxation measurements

  1. Effects of mode coupling between low-mode radiation flux asymmetry and intermediate-mode ablator roughness on ignition capsule implosions

    Directory of Open Access Journals (Sweden)

    Jianfa Gu

    2017-01-01

    Full Text Available The low-mode shell asymmetry and high-mode hot spot mixing appear to be the main reasons for the performance degradation of the National Ignition Facility (NIF implosion experiments. The effects of the mode coupling between low-mode P2 radiation flux asymmetry and intermediate-mode L = 24 capsule roughness on the implosion performance of ignition capsule are investigated by two-dimensional radiation hydrodynamic simulations. It is shown that the amplitudes of new modes generated by the mode coupling are in good agreement with the second-order mode coupling equation during the acceleration phase. The later flow field not only shows large areal density P2 asymmetry in the main fuel, but also generates large-amplitude spikes and bubbles. In the deceleration phase, the increasing mode coupling generates more new modes, and the perturbation spectrum on the hot spot boundary is mainly from the strong mode interactions rather than the initial perturbation conditions. The combination of the low-mode and high-mode perturbations breaks up the capsule shell, resulting in a significant reduction of the hot spot temperature and implosion performance.

  2. Lunar dusty plasma: A result of interaction of the solar wind flux and ultraviolet radiation with the lunar surface

    International Nuclear Information System (INIS)

    Lisin, E A; Tarakanov, V P; Petrov, O F; Popel, S I

    2015-01-01

    One of the main problems of future missions to the Moon is associated with lunar dust. Solar wind flux and ultraviolet radiation interact with the lunar surface. As a result, there is a substantial surface change and a near-surface plasma sheath. Dust particles from the lunar regolith, which turned in this plasma because of any mechanical processes, can levitate above the surface, forming dust clouds. In preparing of the space experiments “Luna-Glob” and “Luna-Resource” particle-in-cell calculations of the near-surface plasma sheath parameters are carried out. Here we present some new results of particle-in-cell simulation of the plasma sheath formed near the surface of the moon as a result of interaction of the solar wind and ultraviolet radiation with the lunar surface. The conditions of charging and stable levitation of dust particles in plasma above the lunar surface are also considered. (paper)

  3. POLAMI: Polarimetric Monitoring of Active Galactic Nuclei at Millimetre Wavelengths - III. Characterization of total flux density and polarization variability of relativistic jets

    Science.gov (United States)

    Agudo, Iván; Thum, Clemens; Ramakrishnan, Venkatessh; Molina, Sol N.; Casadio, Carolina; Gómez, José L.

    2018-01-01

    We report on the first results of the POLAMI (Polarimetric Monitoring of AGNs with Millimetre Wavelengths) programme, a simultaneous 3.5 and 1.3 mm full-Stokes-polarization monitoring of a sample of 36 of the brightest active galactic nuclei in the northern sky with the IRAM 30 m telescope. Through a systematic statistical study of data taken from 2006 October (from 2009 December for the case of the 1.3 mm observations) to 2014 August, we characterize the variability of the total flux density and linear polarization. We find that all sources in the sample are highly variable in total flux density at both 3.5 and 1.3 mm, as well as in spectral index, which (except in particularly prominent flares) is found to be optically thin between these two wavelengths. The total flux-density variability at 1.3 mm is found, in general, to be faster, and to have larger fractional amplitude and flatter power-spectral-density slopes than at 3.5 mm. The polarization degree is on average larger at 1.3 mm than at 3.5 mm, by a factor of 2.6. The variability of linear polarization degree is faster and has higher fractional amplitude than for total flux density, with the typical time-scales during prominent polarization peaks being significantly faster at 1.3 mm than at 3.5 mm. The polarization angle at both 3.5 and 1.3 mm is highly variable. Most of the sources show one or two excursions of >180° on time-scales from a few weeks to about a year during the course of our observations. The 3.5 and 1.3 mm polarization angle evolution follows each other rather well, although the 1.3 mm data show a clear preference to more prominent variability on the short time-scales, i.e. weeks. The data are compatible with multizone models of conical jets involving smaller emission regions for the shortest-wavelength emitting sites. Such smaller emitting regions should also be more efficient in energising particle populations, as implied by the coherent evolution of the spectral index and the total flux

  4. Self-pumping effects and radiation linewidth of Josephson flux-flow oscillators

    DEFF Research Database (Denmark)

    Koshelets, V.P.; Shitov, S.V.; Shchukin, A.V.

    1997-01-01

    Flux-flow oscillators (FFO's) are being developed for integration with a SIS mixer for use in submillimeter wave receivers, The present work contains a detailed experimental study of the dc, microwave, and noise properties of Nb-AlOx-Nb FFO's, A model based on the Josephson self-pumping effect...

  5. Effect of texture and grain size on magnetic flux density and core loss in non-oriented electrical steel containing 3.15% Si

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K.M.; Park, S.Y. [Department of Materials Science and Engineering, Korea University, 5-1, Anam-dong, Sungbuk-Gu, Seoul 136-701 (Korea, Republic of); Huh, M.Y., E-mail: myhuh@korea.ac.kr [Department of Materials Science and Engineering, Korea University, 5-1, Anam-dong, Sungbuk-Gu, Seoul 136-701 (Korea, Republic of); Kim, J.S. [Electrical Steel Sheet Research Group, Technical Research Laboratories, POSCO, Goedong-dong, Pohang (Korea, Republic of); Engler, O. [Hydro Aluminium Rolled Products GmbH, R and D Center Bonn, P.O. Box 2468, D-53014 Bonn (Germany)

    2014-03-15

    In an attempt to differentiate the impact of grain size and crystallographic texture on magnetic properties of non-oriented (NO) electrical steel sheets, samples with different grain sizes and textures were produced and analyzed regarding magnetic flux density B and core loss W. The textures of the NO electrical steel samples could be precisely quantified with the help of elliptical Gaussian distributions. In samples with identical textures, small grain sizes resulted in about 15% higher core loss W than larger grains, whereas grain size only moderately affected the magnetic flux density B. In samples having nearly the same grain size, a correlation of the magneto-crystalline anisotropic properties of B and W with texture was obtained via the anisotropy parameter A(h{sup →}). With increasing A(h{sup →}) a linear decrease of B and a linear increase of W were observed. - Highlights: • We produced electrical steel sheets having different grain size and texture. • Magnetic flux density B and core loss W were varied with grain size and texture. • Correlation of B and W with texture was established via anisotropy parameter A(h{sup →}). • With increasing A(h{sup →}) a linear decrease of B and a linear increase of W were observed. • Grain size mainly affected W with only minor impact on B.

  6. Transient radiative hydromagnetic free convection flow past an impulsively started vertical plate with uniform heat and mass flux

    Directory of Open Access Journals (Sweden)

    Prasad Ramachandra V.

    2006-01-01

    Full Text Available The interaction of free convection with thermal radiation of viscous incompressible MHD unsteady flow past an impulsively started vertical plate with uniform heat and mass flux is analyzed. This type of problem finds application in many technological and engineering fields such as rocket propulsion systems, space craft re-entry aerothermodynamics, cosmical flight aerodynamics, plasma physics, glass production and furnace engineering .The Rosseland approximation is used to describe the radiative heat transfer in the limit of the optically thin fluid. The non-linear, coupled equations are solved using an implicit finite difference scheme of Crank-Nicolson type. Velocity, temperature and concentration of the flow have been presented for various parameters such as thermal Grashof number, mass Grashof number, Prandtl number, Schmidt number, radiation parameter and magnetic parameter. The local and average skin friction, Nusslet number and Sherwood number are also presented graphically. It is observed that, when the radiation parameter increases the velocity and temperature decrease in the boundary layer. .

  7. Decomposing Shortwave Top-of-Atmosphere Radiative Flux Variability in Terms of Surface and Atmospheric Contributions Using CERES Observations

    Science.gov (United States)

    Loeb, N. G.; Wong, T.; Wang, H.

    2017-12-01

    Earth's climate is determined by the exchange of radiant energy between the Sun, Earth and space. The absorbed solar radiation (ASR) fuels the climate system, providing the energy required for atmospheric and oceanic motions, while the system cools by emitting outgoing longwave (LW) radiation to space. A central objective of the Clouds and the Earth's Radiant Energy System (CERES) is to produce a long-term global climate data record of Earth's radiation budget along with the associated atmospheric and surface properties that influence it. CERES data products utilize a number of data sources, including broadband radiometers measuring incoming and reflected solar radiation and OLR, polar orbiting and geostationary spectral imagers, meteorological, aerosol and ozone assimilation data, and snow/sea-ice maps based on microwave radiometer data. Here we use simple diagnostic model of Earth's albedo and CERES Energy Balanced and Filled (EBAF) Ed4.0 data for March 2000-February 2016 to quantify interannual variations in SW TOA flux associated with surface albedo and atmospheric reflectance and transmittance variations. Surface albedo variations account for cloud properties over the Arctic Ocean.

  8. Impact of heat source/sink on radiative heat transfer to Maxwell nanofluid subject to revised mass flux condition

    Science.gov (United States)

    Khan, M.; Irfan, M.; Khan, W. A.

    2018-06-01

    Nanofluids retain noteworthy structure that have absorbed attentions of numerous investigators because of their exploration in nanotechnology and nanoscience. In this scrutiny a mathematical computation of 2D flows of Maxwell nanoliquid influenced by a stretched cylinder has been established. The heat transfer structure is conceded out in the manifestation of thermal radiation and heat source/sink. Moreover, the nanoparticles mass flux condition is engaged in this exploration. This newly endorsed tactic is more realistic where the conjecture is made that the nanoparticle flux is zero and nanoparticle fraction regulates itself on the restrictions consequently. By utilizing apposite conversion the governing PDEs are transformed into ODEs and then tackled analytically via HAM. The attained outcomes are plotted and deliberated in aspect for somatic parameters. It is remarked that with an intensification in the Deborah number β diminish the liquid temperature while it boosts for radiation parameter Rd . Furthermore, the concentration of Maxwell liquid has conflicting impact for Brownian motion Nb and thermophoresis parameters Nt .

  9. Analytic solutions in the dyon black hole with a cosmic string: Scalar fields, Hawking radiation and energy flux

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, H.S., E-mail: horacio.santana.vieira@hotmail.com [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil); Centro de Ciências, Tecnologia e Saúde, Universidade Estadual da Paraíba, CEP 58233-000, Araruna, PB (Brazil); Bezerra, V.B., E-mail: valdir@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil); Silva, G.V., E-mail: gislainevs@hotmail.com [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil)

    2015-11-15

    Charged massive scalar fields are considered in the gravitational and electromagnetic field produced by a dyonic black hole with a cosmic string along its axis of symmetry. Exact solutions of both angular and radial parts of the covariant Klein–Gordon equation in this background are obtained, and are given in terms of the confluent Heun functions. The role of the presence of the cosmic string in these solutions is showed up. From the radial solution, we obtain the exact wave solutions near the exterior horizon of the black hole, and discuss the Hawking radiation spectrum and the energy flux. -- Highlights: •A cosmic string is introduced along the axis of symmetry of the dyonic black hole. •The covariant Klein–Gordon equation for a charged massive scalar field in this background is analyzed. •Both angular and radial parts are transformed to a confluent Heun equation. •The resulting Hawking radiation spectrum and the energy flux are obtained.

  10. Effect of low-power density laser radiation on heatling of open skin wounds in rats

    Energy Technology Data Exchange (ETDEWEB)

    Kana, J.S.; Hutschenreiter, G.; Haina, D.; Waidelich, W.

    1981-03-01

    Researchers performed a study to determine whether laser radation of low-power density would affect the healing of open skin wounds in rats. The wounds were irradiated daily with a helium-neon laser and an argon laser at a constant power density of 45 mW/sq cm. The rate of wound closure was followed by photographing the wounds in a standardized way. The collagen hydroxyproline concentration in the scar tissue was determined on the 18th postoperative day. Helium-neon laser radiation had a statistically significant stimulating effect on collagen synthesis in the wound, with a maximum effect at an energy density of 4 joules/sq cm. The rate of wound closure was enhanced significantly between the third and 12th postoperative days. The argon laser exposure produced a significant increase in collagen concentration both in irradiated and nonirradiated contralateral wounds. However, an acceleration of the healing rate was not registered in this case. The wound contraction up to the fourth day of the experiment was inhibited under helium-neon and argon laser exposure to 20 joules/sq cm. The described effects were not specific for the laser light. There may be a wavelength-selective influence of coherent light on the metabolic and proliferation processes in wound healing, with the associated problem of the possible carcinogenic effects of laser radiation.

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

    International Nuclear Information System (INIS)

    Ekedahl, A.; Colas, L.; Beaumont, B.; Bibet, Ph.; Bremond, S.; Kazarian, F.; Noterdaeme, J.M.; Tuccillo, A.A.

    2003-01-01

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

  12. Density Convection near Radiating ICRF Antennas and its Effect on the Coupling of Lower Hybrid Waves

    International Nuclear Information System (INIS)

    Ekedahl, A.; Colas, L.; Beaumont, B.; Bibet, Ph.; Bremond, S.; Kazarian, F.; Mayoral, M.-L.; Mailloux, J.; Noterdaeme, J.-M.; Tuccillo, A.A.

    2003-01-01

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

  13. On the determination of the overall heat transmission coefficient and soil heat flux for a fog cooled, naturally ventilated greenhouse: Analysis of radiation and convection heat transfer

    International Nuclear Information System (INIS)

    Abdel-Ghany, Ahmed M.; Kozai, Toyoki

    2006-01-01

    A physical model for analyzing the radiative and convective heat transfer in a fog cooled, naturally ventilated greenhouse was developed for estimating the overall heat transmission coefficient based on the conduction, convection and thermal radiation heat transfer coefficients and for predicting the soil heat flux. The contribution of the water vapor of the inside air to the emission and absorption of thermal radiation was determined. Measurements of the outside and inside greenhouse environments to be used in the analysis were conducted around solar noon (12:19-13:00) on a hot sunny day to provide the maximum solar radiation transmission into the greenhouse. The net solar radiation flux measured at the greenhouse floor showed a reasonable agreement with the predicted value. The net fluxes were estimated around noon. The average net radiation (solar and thermal) at the soil surface was 220.0 W m -2 , the average soil heat flux was 155.0 W m -2 and the average contribution of the water vapor of the inside air to the thermal radiation was 22.0 W m -2 . The average overall heat transmission coefficient was 4.0 W m -2 C -1 and was in the range between 3.0 W m -2 C -1 and 6.0 W m -2 C -1 under the different hot summer conditions between the inside and outside of the naturally ventilated, fog cooled greenhouse

  14. Quantifying the impact of cloud cover on ground radiation flux measurements using hemispherical images

    NARCIS (Netherlands)

    Roupioz, L.; Colin, J.; Jia, L.; Nerry, F.; Menenti, M.

    2015-01-01

    Linking observed or estimated ground incoming solar radiation with cloud coverage is difficult since the latter is usually poorly described in standard meteorological observation protocols. To investigate the benefits of detailed observation and characterization of cloud coverage and

  15. A model to calculate solar radiation fluxes on the Martian surface

    Directory of Open Access Journals (Sweden)

    Vicente-Retortillo Álvaro

    2015-01-01

    Full Text Available We present a new comprehensive radiative transfer model to study the solar irradiance that reaches the surface of Mars in the spectral range covered by MetSIS, a sensor aboard the Mars MetNet mission that will measure solar irradiance in several bands from the ultraviolet (UV to the near infrared (NIR. The model includes up-to-date wavelength-dependent radiative properties of dust, water ice clouds, and gas molecules. It enables the characterization of the radiative environment in different spectral regions under different scenarios. Comparisons between the model results and MetSIS observations will allow for the characterization of the temporal variability of atmospheric optical depth and dust size distribution, enhancing the scientific return of the mission. The radiative environment at the Martian surface has important implications for the habitability of Mars as well as a strong impact on its atmospheric dynamics and climate.

  16. SU-G-TeP3-10: Radiation Induces Prompt Live-Cell Metabolic Fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Campos, D [University of Wisconsin Madison, Madison, WI (United States); Peeters, W; Bussink, J [Radboud University Medical Center, Nijmegen, GA (United States); Nickel, K [University of Wisconsin - Madison, Madison, Wisconsin (United States); Burkel, B; Kimple, R; Kogel, A van der; Eliceiri, K [University of Wisconsin - Madison, Madison, WI (United States); Kissick, M [University of Wisconsin, Madison, WI (United States)

    2016-06-15

    Purpose: To compare metabolic dynamics and HIF-1α expression following radiation between a cancerous cell line (UM-SCC-22B) and a normal, immortalized cell line, NOK (Normal Oral Keratinocyte). HIF-1 is a key factor in metabolism and radiosensitivity. A better understanding of how radiation affects the interplay of metabolism and HIF-1 might give a better understanding of the mechanisms responsible for radiosensitivity. Methods: Changes in cellular metabolism in response to radiation are tracked by fluorescence lifetime of NADH. Expression of HIF-1α was measured by immunofluorescence for both cell lines with and without irradiation. Radiation response is also monitored with additional treatment of a HIF-1α inhibitor (chrysin) as well as a radical scavenger (glutathione). Changes in oxygen consumption and respiratory capacity are also monitored using the Seahorse XF analyzer. Results: An increase in HIF-1α was found to be in response to radiation for the cancer cell line, but not the normal cell line. Radiation was found to shift metabolism toward glycolytic pathways in cancer cells as measured by oxygen consumption and respiratory capacity. Radiation response was found to be muted by addition of glutathione to cell media. HIF-1α inhibition similarly muted radiation response in cancer. Conclusion: The HIF-1 protein complex is a key regulator cellular metabolism through the regulation of glycolysis and glucose transport enzymes. Moreover, HIF-1 has shown radio-protective effects in tumor vascular endothelia, and has been implicated in metastatic aggression. Monitoring interplay between metabolism and the HIF-1 protein complex can give a more fundamental understanding of radiotherapy response.

  17. SU-G-TeP3-10: Radiation Induces Prompt Live-Cell Metabolic Fluxes

    International Nuclear Information System (INIS)

    Campos, D; Peeters, W; Bussink, J; Nickel, K; Burkel, B; Kimple, R; Kogel, A van der; Eliceiri, K; Kissick, M

    2016-01-01

    Purpose: To compare metabolic dynamics and HIF-1α expression following radiation between a cancerous cell line (UM-SCC-22B) and a normal, immortalized cell line, NOK (Normal Oral Keratinocyte). HIF-1 is a key factor in metabolism and radiosensitivity. A better understanding of how radiation affects the interplay of metabolism and HIF-1 might give a better understanding of the mechanisms responsible for radiosensitivity. Methods: Changes in cellular metabolism in response to radiation are tracked by fluorescence lifetime of NADH. Expression of HIF-1α was measured by immunofluorescence for both cell lines with and without irradiation. Radiation response is also monitored with additional treatment of a HIF-1α inhibitor (chrysin) as well as a radical scavenger (glutathione). Changes in oxygen consumption and respiratory capacity are also monitored using the Seahorse XF analyzer. Results: An increase in HIF-1α was found to be in response to radiation for the cancer cell line, but not the normal cell line. Radiation was found to shift metabolism toward glycolytic pathways in cancer cells as measured by oxygen consumption and respiratory capacity. Radiation response was found to be muted by addition of glutathione to cell media. HIF-1α inhibition similarly muted radiation response in cancer. Conclusion: The HIF-1 protein complex is a key regulator cellular metabolism through the regulation of glycolysis and glucose transport enzymes. Moreover, HIF-1 has shown radio-protective effects in tumor vascular endothelia, and has been implicated in metastatic aggression. Monitoring interplay between metabolism and the HIF-1 protein complex can give a more fundamental understanding of radiotherapy response.

  18. Exposure to long wavelength ultraviolet radiation decreases processing of low density lipoprotein by cultured human fibroblasts

    International Nuclear Information System (INIS)

    Djavaheri-Mergny, M.; Santus, R.; Mora, L.; Maziere, J.C.; Faculte de Medecine Saint-Antoine, 75 -Paris; Maziere, C.; Auclair, M.; Dubertret, L.

    1993-01-01

    Exposure of MRC5 human fibroblasts to UVA radiation (365 nm) resulted in a dose-dependent decrease in low density lipoprotein (LDL) uptake and degradation by cells. Following a 25 J/cm 2 irradiation dose, about 45% and 70% reduction in 125 I-LDL uptake and degradation were observed, respectively. Under the same conditions, the 14 C-sucrose uptake was also decreased to about the same extent as LDL uptake. Cell pretreatment with the antioxidants vitamin E and vitamin C did not prevent the UVA-induced fall in LDL degradation. These results point to the possible effects of UVA radiation on receptor-mediated and nonspecific uptake of exogenous molecules. With special regard to the alterations in receptor-mediated processing of exogenous ligands, such a phenomenon could be of importance in UVA-induced skin degenerative processes. (Author)

  19. Search for ionisation density effects in the radiation absorption stage in LiF:Mg,Ti

    International Nuclear Information System (INIS)

    Nail, I.; Horowitz, Y. S.; Oster, L.; Brandan, M. E.; Rodriguez-Villafuerte, M.; Buenfil, A. E.; Ruiz-Trejo, C.; Gamboa-deBuen, I.; Avila, O.; Tovar, V. M.; Olko, P.; Ipe, N.

    2006-01-01

    Optical absorption (OA) dose-response of LiF:Mg,Ti (TLD-100) is studied as a function of electron energy (ionisation density) and irradiation dose. Contrary to the situation in thermoluminescence dose-response where the supra-linearity is strongly energy-dependent, no dependence of the OA dose filling constants on energy is observed. This result is interpreted as indicating a lack of competitive process in the radiation absorption stage. The lack of an energy dependence of the dose filling constant also suggests that the charge carrier migration distances are sufficiently large to smear out the differences in the non-uniform distribution of ionisation events created by the impinging gamma/ electron radiation of various energies. (authors)

  20. Parametrization of the average ionization and radiative cooling rates of carbon plasmas in a wide range of density and temperature

    OpenAIRE

    Gil de la Fe, Juan Miguel; Rodriguez Perez, Rafael; Florido, Ricardo; Garcia Rubiano, Jesus; Mendoza, M.A.; Nuez, A. de la; Espinosa, G.; Martel Escobar, Carlos; Mínguez Torres, Emilio

    2013-01-01

    In this work we present an analysis of the influence of the thermodynamic regime on the monochromatic emissivity, the radiative power loss and the radiative cooling rate for optically thin carbon plasmas over a wide range of electron temperature and density assuming steady state situations. Furthermore, we propose analytical expressions depending on the electron density and temperature for the average ionization and cooling rate based on polynomial fittings which are valid for the whole range...

  1. Influence of reagents mixture density on the radiation-thermal synthesis of lithium-zinc ferrites

    Science.gov (United States)

    Surzhikov, A. P.; Lysenko, E. N.; Vlasov, V. A.; Malyshev, A. V.; Korobeynikov, M. V.; Mikhailenko, M. A.

    2017-01-01

    Influence of Li2CO3-ZnO-Fe2O3 powder reagents mixture density on the synthesis efficiency of lithium-zinc ferrites in the conditions of thermal heating or pulsed electron beam heating was studied by X-Ray diffraction and magnetization analysis. The results showed that the including a compaction of powder reagents mixture in ferrite synthesis leads to an increase in concentration of the spinel phase and decrease in initial components content in lithium-substituted ferrites synthesized by thermal or radiation-thermal heating.

  2. Non-primordial origin of the cosmic background radiation and pregalactic density fluctuations

    International Nuclear Information System (INIS)

    Froehlich, H.E.; Mueller, V.; Oleak, H.

    1984-01-01

    Assumptions of a tepid Universe and a smaller primordial contribution to the 3 K background are made to show that Pop III stars may be responsible for the 3 K background and cosmic ray entropy. The 3 K background would be caused by thermalized stellar radiation produced by metallized intergalactic dust formed in first generation stars. A range of mass scales and amplification factors of density perturbations in the early Universe is examined below the Jeans mass for gravitational instabilities. The density perturbations that could have been present at small enough mass scales could have survived and generated sonic modes that propagated through the plasma era and, when combined with additional gravitationally unstable entropy disturbances after recombination, triggered the formation of Pop III stars. 13 references

  3. Effects of solar radiation on the abiotic and bacterially mediated carbon flux in aquatic ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Anesio, A.M.

    2000-05-01

    In this thesis, I studied some of the current aspects of organic matter photochemistry. I analyzed abiotic photo transformations of several types of dissolved (DOM) and particulate organic matter (POM). I also evaluated the effects of photo transformation of several types of DOM on bacteria. Finally, in a field experiment, I analyzed net effects of solar radiation on organic matter decomposition. DOM undergoes several transformations due to solar irradiation. One such transformation is photooxidation of organic matter into inorganic carbon. Results of this Thesis show that photooxidation is ubiquitous to all kinds of organic matter in both dissolved and particulate forms. The intensity of this process depends on several factors, including DOM composition, radiation type and time of exposure. Besides mineralization to inorganic carbon, DOM undergoes other chemical transformations due to UV radiation, with profound consequences to DOM availability for bacteria. Bioavailability was tested by measuring bacterial growth and respiration on irradiated and nonirradiated DOM from several types of humic matter and plant leachates. Irradiation of freshly-leached DOM often produced negative effects on bacteria, whereas irradiation of humic material was followed by stimulation of bacterial growth. The degree of stimulation seems to be related to the initial bioavailability of the DOM and to the capability of the DOM to produce hydrogen peroxide upon irradiation. Other factors also accounted for differences in bacterial response to photochemical modification of DOM, including length and type of irradiation exposure. The effects of solar radiation on litter decomposition were also evaluated using experiments that more closely mimic natural conditions. I could not observe differences between dry weight loss of leaves and culms exposed to solar radiation or kept in darkness, which may be explained by the fact that abiotic decomposition under solar radiation is counterbalanced by

  4. Regional Lung Density Changes After Radiation Therapy for Tumors in and Around Thorax

    International Nuclear Information System (INIS)

    Ma Jinli; Zhang Junan; Zhou Sumin; Hubbs, Jessica L.; Foltz, Rodney J.; Hollis, Donna R.; Light, Kim L.; Wong, Terence Z.; Kelsey, Christopher R.; Marks, Lawrence B.

    2010-01-01

    Purpose: To study the temporal nature of regional lung density changes and to assess whether the dose-dependent nature of these changes is associated with patient- and treatment-associated factors. Methods and Materials: Between 1991 and 2004, 118 patients with interpretable pre- and post-radiation therapy (RT) chest computed tomography (CT) scans were evaluated. Changes in regional lung density were related to regional dose to define a dose-response curve (DRC) for RT-induced lung injury using three-dimensional planning tools and image fusion. Multiple post-RT follow-up CT scans were evaluated by fitting linear-quadratic models of density changes on dose with time as the covariate. Various patient- and treatment-related factors were examined as well. Results: There was a dose-dependent increase in regional lung density at nearly all post-RT follow-up intervals. The population volume-weighted changes evolved over the initial 6-month period after RT and reached a plateau thereafter (p < 0.001). On univariate analysis, patient age greater than 65 years (p = 0.003) and/or the use of pre-RT surgery (p < 0.001) were associated with significantly greater changes in CT density at both 6 and 12 months after RT, but the magnitude of this effect was modest. Conclusions: There appears to be a temporal nature for the dose-dependent increases in lung density. Nondosimetric clinical factors tend to have no, or a modest, impact on these changes.

  5. Surface renewal: an advanced micrometeorological method for measuring and processing field-scale energy flux density data.

    Science.gov (United States)

    McElrone, Andrew J; Shapland, Thomas M; Calderon, Arturo; Fitzmaurice, Li; Paw U, Kyaw Tha; Snyder, Richard L

    2013-12-12

    Advanced micrometeorological methods have become increasingly important in soil, crop, and environmental sciences. For many scientists without formal training in atmospheric science, these techniques are relatively inaccessible. Surface renewal and other flux measurement methods require an understanding of boundary layer meteorology and extensive training in instrumentation and multiple data management programs. To improve accessibility of these techniques, we describe the underlying theory of surface renewal measurements, demonstrate how to set up a field station for surface renewal with eddy covariance calibration, and utilize our open-source turnkey data logger program to perform flux data acquisition and processing. The new turnkey program returns to the user a simple data table with the corrected fluxes and quality control parameters, and eliminates the need for researchers to shuttle between multiple processing programs to obtain the final flux data. An example of data generated from these measurements demonstrates how crop water use is measured with this technique. The output information is useful to growers for making irrigation decisions in a variety of agricultural ecosystems. These stations are currently deployed in numerous field experiments by researchers in our group and the California Department of Water Resources in the following crops: rice, wine and raisin grape vineyards, alfalfa, almond, walnut, peach, lemon, avocado, and corn.

  6. [Sap flux density in response to rainfall pulses for Pinus tabuliformis and Hippophae rhamnoides from mixed plantation in hilly Loess Plateau].

    Science.gov (United States)

    Lu, Sen Bao; Chen, Yun Ming; Tang, Ya Kun; Wu, Xu; Wen, Jie

    2017-11-01

    Thermal dissipation probe (TDP) was used to continuously measure the sap flux density (F d ) of Pinus tabuliformis and Hippophae rhamnoides individuals in hilly Loess Plateau, from June to October 2015, and the environmental factors, i.e., photosynthetic active radiation (PAR), water vapor pressure deficit (VPD), and soil water content (SWC), were simultaneously monitored to clarify the difference of rainfall utilization between the two tree species in a mixed plantation. Using the methods of a Threshold-delay model, stepwise multiple regression analyses, and partial correlation analyses, this paper studied the process of F d in these two species in response to the rainfall pulses and then determined the effects of environmental factors on F d . The results showed that, with the increase of rainfall, the response percentages of F d in both P. tabuliformis and H. rhamnoides increased at first but then decreased; specifically, in the range of 0-1 mm rainfall, the F d of P. tabuliformis (-16.3%) and H. rhamnoides (-6.3%) clearly decreased; in the range of 1-5 mm rainfall, the F d of P. tabuliformis decreased (-0.4%), whereas that of H. rhamnoides significantly increased (9.0%). The lower rainfall thresholds (R L ) of F d for P. tabuliformis and H. rhamnoides were 6.4 and 1.9 mm, respectively, with a corresponding time-lag (τ) of 1.96 and 1.67 days. In the pre-rainfall period, the peak time of F d of P. tabuliformis converged upon 12:00-12:30 (70%), while the F d of H. rhamnoides peaked twice, between 10:30 and 12:00 (48%) and again between 16:00 and 16:30 (30%). In the post-rainfall period, the peak time of F d of P. tabuliformis converged upon 11:00-13:00 (40%), while that of H. rhamnoides peaked twice, between 12:00 and 13:00 (52%) and again between 16:30 and 17:00 (24%). Among the environmental factors, the rank order of factors associated with the F d of both P. tabuliformis and H. rhamnoides was PAR>VPD, before rainfall. However, the rank order of factors

  7. Systematics of radiation widths and level density parameters in the mass number range region 40

    International Nuclear Information System (INIS)

    Bychkov, V.M.; Grudzevich, O.T.; Plyaskin, V.I.

    1990-01-01

    We suggest a systematics of radiation width based on a reduced radiative capture strength function for the E1-transition, which eliminates fluctuations in the analysed quantity with neutron binding energy, nuclear level density and γ-quanta energy. A smooth dependence for the fitting parameter of the radiative strength function for E1-transitions in relation to the relative atomic mass of the nucleus is obtained. 10 refs, 2 figs

  8. Effects of Radiation and a High Iron Load on Bone Mineral Density

    Science.gov (United States)

    Yuen, E.; Morgan, J. L. L.; Zwart, S. R.; Gonzales, E.; Camp, K.; Smith, S. M.; Bloomfield, S. A.

    2012-01-01

    Astronauts on long duration space flight missions to the moon or mars are exposed to radiation and have increase iron (Fe) stores, both of which can independently induce oxidative stress and may exacerbate bone mass loss and strength. We hypothesize a high Fe diet and a fractionated gamma radiation exposure would increase oxidative stress and lower bone mass. Three mo-old, SD rats (n=32) were randomized to receive an adequate Fe diet (45 mg Fe/kg diet) or a high Fe diet (650 mg Fe/kg diet) for 4 wks and either a cumulative 3 Gy dose (fractionated 8 x 0.375 Gy) of gamma radiation (Cs-137) or sham exposure starting on day 14. Elisa kit assessed serum catalase, clinical analyzer assessed serum Fe status and ex vivo pQCT scans measured bone parameters in the proximal/midshaft tibia and femoral neck. Mechanical strength was assessed by 3-pt bending and femoral neck test. There is a significant decrease in trabecular bone mineral density (BMD) from radiation (p less than 0.05) and a trend in diet (p=0.05) at the proximal tibia. There is a significant interaction in cortical BMD from the combined treatments at the midshaft tibia (p less than 0.05). There is a trending decrease in total BMD from diet (p=0.07) at the femoral neck. In addition, high serum Fe was correlated to low trabecular BMD (p less than 0.05) and high serum catalase was correlated to low BMD at all 3 bone sites (p less than 0.05). There was no difference in the max load of the tibia or femoral neck. Radiation and a high iron diet increases iron status and catalase in the serum and decreases BMD.

  9. Couplings between the seasonal cycles of surface thermodynamics and radiative fluxes in the semi-arid Sahel

    Science.gov (United States)

    Guichard, F.; Kergoat, L.; Mougin, E.; Timouk, F.; Bock, O.; Hiernaux, P.

    2009-04-01

    A good knowledge of surface fluxes and atmospheric low levels is central to improving our understanding of the West African monsoon. This study provides a quantitative analysis of the peculiar seasonal and diurnal cycles of surface thermodynamics and radiative fluxes encountered in Central Sahel. It is based on a multi-year dataset collected in the Malian Gourma over a sandy soil at 1.5°W-15.3°N (a site referred to as Agoufou) with an automated weather station and a sunphotometer (AERONET), complemented by observations from the AMMA field campaign. The seasonal cycle of this Tropical region is characterized by a broad maximum of temperature in May, following the first minimum of the solar zenith angle by a few weeks, when Agoufou lies within the West African Heat-Low, and a late summer maximum of equivalent potential temperature within the core of the monsoon season, around the second yearly maximum of solar zenith angle, as the temperature reaches its Summer minimum. More broadly, subtle balances between surface air temperature and moisture fields are found on a range of scales. For instance, during the monsoon, apart from August, their opposite daytime fluctuations (warming, drying) lead to an almost flat diurnal cycle of the equivalent potential temperature at the surface. This feature stands out in contrast to other more humid continental regions. Here, the strong dynamics associated with the transition from a drier hot Spring to a brief cooler wet tropical Summer climate involves very large transformations of the diurnal cycles. The Summer increase of surface net radiation, Rnet, is also strong; typically 10-day mean Rnet reaches about 5 times its Winter minimum (~30 W.m-2) in August (~150 W.m-2). A major feature revealed by observations is that this increase is mostly driven by modifications of the surface upwelling fluxes shaped by rainfall events and vegetation phenology (surface cooling and darkening), while the direct impact of atmospheric changes on

  10. Compatibility of advanced tokamak plasma with high density and high radiation loss operation in JT-60U

    International Nuclear Information System (INIS)

    Takenaga, H.; Asakura, N.; Kubo, H.; Higashijima, S.; Konoshima, S.; Nakano, T.; Oyama, N.; Ide, S.; Fujita, T.; Takizuka, T.; Kamada, Y.; Miura, Y.; Porter, G.D.; Rognlien, T.D.; Rensink, M.E.

    2005-01-01

    Compatibility of advanced tokamak plasmas with high density and high radiation loss has been investigated in both reversed shear (RS) plasmas and high β p H-mode plasmas with a weak positive shear on JT-60U. In the RS plasmas, the operation regime is extended to high density above the Greenwald density (n GW ) with high confinement (HH y2 >1) and high radiation loss fraction (f rad >0.9) by tailoring the internal transport barriers (ITBs). High confinement of HH y2 =1.2 is sustained even with 80% radiation from the main plasma enhanced by accumulated metal impurity. The divertor radiation is enhanced by Ne seeding and the ratio of the divertor radiation to the total radiation is increased from 20% without seeding to 40% with Ne seeding. In the high β p H-mode plasmas, high confinement (HH y2 =0.96) is maintained at high density (n-bar e /n GW =0.92) with high radiation loss fraction (f rad ∼1) by utilizing high-field-side pellets and Ar injections. The high n-bar e /n GW is obtained due to a formation of clear density ITB. Strong core-edge parameter linkage is observed, as well as without Ar injection. In this linkage, the pedestal β p , defined as β p ped =p ped /(B p 2 /2μ 0 ) where p ped is the plasma pressure at the pedestal top, is enhanced with the total β p . The radiation profile in the main plasma is peaked due to Ar accumulation inside the ITB and the measured central radiation is ascribed to Ar. The impurity transport analyses indicate that Ar accumulation by a factor of 2 more than the electron, as observed in the high β p H-mode plasma, is acceptable even with peaked density profile in a fusion reactor for impurity seeding. (author)

  11. Study of electron densities of normal and neoplastic human breast tissues by Compton scattering using synchrotron radiation

    International Nuclear Information System (INIS)

    Antoniassi, M.; Conceição, A.L.C.; Poletti, M.E.

    2012-01-01

    Electron densities of 33 samples of normal (adipose and fibroglangular) and neoplastic (benign and malignant) human breast tissues were determined through Compton scattering data using a monochromatic synchrotron radiation source and an energy dispersive detector. The area of Compton peaks was used to determine the electron densities of the samples. Adipose tissue exhibits the lowest values of electron density whereas malignant tissue the highest. The relationship with their histology was discussed. Comparison with previous results showed differences smaller than 4%. - Highlights: ► Electron density of normal and neoplastic breast tissues was measured using Compton scattering. ► Monochromatic synchrotron radiation was used to obtain the Compton scattering data. ► The area of Compton peaks was used to determine the electron densities of samples. ► Adipose tissue shows the lowest electron density values whereas the malignant tissue the highest. ► Comparison with previous results showed differences smaller than 4%.

  12. A two dimensional modeling study of the sensitivity of ozone to radiative flux uncertainties

    International Nuclear Information System (INIS)

    Grant, K.E.; Wuebbles, D.J.

    1988-08-01

    Radiative processes strongly effect equilibrium trace gas concentrations both directly, through photolysis reactions, and indirectly through temperature and transport processes. We have used the LLNL 2-D chemical-radiative-transport model to investigate the net sensitivity of equilibrium ozone concentrations to several changes in radiative forcing. Doubling CO 2 from 300 ppmv to 600 ppmv resulted in a temperature decrease of 5 K to 8 K in the middle stratosphere along with an 8% to 16% increase in ozone in the same region. Replacing our usual shortwave scattering algorithms with a simplified Rayleigh algorithm led to a 1% to 2% increase in ozone in the lower stratosphere. Finally, modifying our normal CO 2 cooling rates by corrections derived from line-by-line calculations resulted in several regions of heating and cooling. We observed temperature changes on the order of 1 K to 1.5 K with corresponding changes of 0.5% to 1.5% in O 3 . Our results for doubled CO 2 compare favorably with those by other authors. Results for our two perturbation scenarios stress the need for accurately modeling radiative processes while confirming the general validity of current models. 15 refs., 5 figs

  13. An experimental study of radiative fluxes in the south Bay of Bengal ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    the Central Radiation Laboratory, Indian Meteoro- logical Department, Pune. The calibration factors are almost similar to those given by the manufac- turer. Also, the performance and accuracy of the radiometer sensors of Kipp and Zonen have been compared with those of Eppley at CAOS, Indian. Institute of Science ...

  14. Gravitational perturbation of the cosmic background radiation by density concentrations. [Swiss cheese model universe

    Energy Technology Data Exchange (ETDEWEB)

    Dyer, C C [Cambridge Univ. (UK). Inst. of Theoretical Astronomy

    1976-05-01

    The gravitational effect of density concentrations in the Universe on the temperature distribution of the cosmic blackbody background radiation is considered, using the Swiss cheese model universe, and supposing each hole to contain an expanding, homogeneous dust sphere at its centre. The temperature profile across such a hole differs in an essential way from that obtained earlier by Rees et al (Nature; 217:511 (1968)). The evolution of this effect with the expansion of the Universe is considered for 'relatively increasing' density contrasts emerging from the same initial singular state as the rest of the Universe. This effect becomes comparable to the bremsstrahlung and Compton effects on the isotropy of the background radiation for masses of about 10/sup 19/ times the mass of the sun, and exceeds these other effects as about Msup(2/3) for larger masses. If large-scale condensations of the Universe can be found for z approximately 1 to 5, delineated, maybe, by the clustering of quasars, etc., then this effect may be observable.

  15. The influence of a spatial displacement of hydrogen on the reactivity and neutron flux density distribution in a ZrH-moderated reactor

    International Nuclear Information System (INIS)

    Doehler, J.; Bartsch, G.

    1975-08-01

    The effect of changes of the hydrogen concentration in uranium zirconium hydride resulting from spatially varying temperatures on the reactivity and neutron flux distribution of the BER-II core (power 2.2 MW) are shown. Furthermore, in general, the influence of the hydrogen concentration on important reactor parameters of a fuel cell of BER-II is calculated and presented. A comparison of the diffusion calculation with spatially constant hydrogen concentrations shows a decrease of the thermal neutron flux density in regions with a low hydrogen content (high temperature) and inversely an increase for high hydrogen concentrations. Furthermore, a change of the effective multiplication factor by 0.6% was found in the case of a spatially varying hydrogen concentration as compared with the calculation for a constant concentration. (orig.) [de

  16. Magnetic-flux pump

    Science.gov (United States)

    Hildebrandt, A. F.; Elleman, D. D.; Whitmore, F. C. (Inventor)

    1966-01-01

    A magnetic flux pump is described for increasing the intensity of a magnetic field by transferring flux from one location to the magnetic field. The device includes a pair of communicating cavities formed in a block of superconducting material, and a piston for displacing the trapped magnetic flux into the secondary cavity producing a field having an intense flux density.

  17. Final Report. Hydrodynamics by high-energy-density plasma flow and hydrodynamics and radiative hydrodynamics with astrophysical application

    International Nuclear Information System (INIS)

    R Paul Drake

    2004-01-01

    OAK-B135 This is the final report from the project Hydrodynamics by High-Energy-Density Plasma Flow and Hydrodynamics and Radiation Hydrodynamics with Astrophysical Applications. This project supported a group at the University of Michigan in the invention, design, performance, and analysis of experiments using high-energy-density research facilities. The experiments explored compressible nonlinear hydrodynamics, in particular at decelerating interfaces, and the radiation hydrodynamics of strong shock waves. It has application to supernovae, astrophysical jets, shock-cloud interactions, and radiative shock waves

  18. Simulation of electron density disturbances of the ionospheric D region produced by high-energy particle fluxes

    International Nuclear Information System (INIS)

    Martynenko, S.I.

    1989-01-01

    Using the large-scale tim expansion analytical solutions of electron concentration balance equation in D-region of the ionosphere for pulsed and periodic changes in the rate of ion formatin under the effect of fluxes of precipitating high-energy particles are obtained. Possible effect of disturbances of temperature of nutrals is taken into account. On the basis of model representations the space-time structure of emerging ionospheric disturbances is discussed

  19. Regions of existence of two forms of the critical void fraction dependence on heat flux density at burnout

    International Nuclear Information System (INIS)

    Smolin, V.N.

    1981-01-01

    On the basis of the available experimental data considered is the burnout during the movement of steam-water flow in vertical heated tubes with internal diameter from 8 to 40 mm. Critical steam content Xsub(cr) dependences on the critical heat flux qsub(cr) in different tubes and under different pressure are analyzed. Two main regions of the weak and strong dependences Xsub(cr)=f(qsub(cr)) at burnout are found out [ru

  20. Study of effects gamma radiation linear low density polyethylene (LLDPE) injected

    International Nuclear Information System (INIS)

    Oliveira, Ana Claudia Feitoza de

    2014-01-01

    The use of package sterilization through gamma radiation aim to reduce the microbiological contamination. The linear low density polyethylene (LLDPE) can be obtained by a process in solution, suspension or gaseous phase, depending on the type of the catalyzer used, that can be heterogeneous, or homogeneous, or metallocenes Ziegler-Natta. According to the literature, the gamma radiation presents a high penetration at polymeric materials causing the appearing of scissions, reticulation, and degradation when oxygen presence. This paper were irradiated with 60 Co with 2000 kCi of activity, in presence of air, samples of LLDPE injected. Utilized doses of 5, 10, 20, 50 or 100 kGy, and about 5 kGy.h -1 dose rates, at room temperature. After irradiation, the samples were heated for 60 min at 100 deg C to promote recombination and annihilation of residual radicals. For characterization of PEBLD were used methods; Melt flow index, swelling, gel fraction, Fourier Transform Infrared (FTIR), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (DRX), Thermogravimetric Analysis (TG), Dynamic Mechanical Analysis (DMA), rheological measurements, Scanning Electronic Microscopy and mechanical tests to identify the effects or gamma radiation in polyethylene. (author)

  1. Downwelling Longwave Fluxes at Continental Surfaces-A Comparison of Observations with GCM Simulations and Implications for the Global Land-Surface Radiation Budget.

    Science.gov (United States)

    Garratt, J. R.; Prata, A. J.

    1996-03-01

    Previous work suggests that general circulation (global climate) models have excess net radiation at land surfaces, apparently due to overestimates in downwelling shortwave flux and underestimates in upwelling long-wave flux. Part of this excess, however, may be compensated for by an underestimate in downwelling longwave flux. Long term observations of the downwelling longwave component at several land stations in Europe, the United States, Australia, and Antarctica suggest that climate models (four are used, as in previous studies) underestimate this flux component on an annual basis by up to 10 W m2, yet with low statistical significance. It is probable that the known underestimate in boundary-layer air temperature contributes to this, as would low model cloudiness and neglect of minor gases such as methane, nitrogen oxide, and the freons. The bias in downwelling longwave flux, together with those found earlier for downwelling shortwave and upwlling long-wave fluxes, are consistent with the model bias found previously for net radiation. All annually averaged fluxes and biases are deduced for global land as a whole.

  2. Photodiode array for position-sensitive detection using high X-ray flux provided by synchrotron radiation

    Science.gov (United States)

    Jucha, A.; Bonin, D.; Dartyge, E.; Flank, A. M.; Fontaine, A.; Raoux, D.

    1984-09-01

    Synchrotron radiation provides a high intensity source over a large range of wavelengths. This is the prominent quality that has laid the foundations of the EXAFS development (Extended X-ray Absorption Fine Structure). EXAFS data can be collected in different ways. A full scan requires 5 to 10 min, compared to the one-day data collection of a conventional Bremsstrahlung X-ray tube. Recently, by using the new photodiode array (R 1024 SFX) manufactured by Reticon, it has been possible to reduce the data collection time to less than 100 ms. The key elements of this new EXAFS method are a dispersive optics combined with a position sensitive detector able to work under very high flux conditions. The total aperture of 2500 μm × 25 μm for each pixel is well suited to spectroscopic applications. Besides its high dynamic range (> 10 4) and its linearity, the rapidity of the readout allows a flux of 10 9-10 10 photons/s over the 1024 sensing elements.

  3. Relationships Between Tropical Deep Convection, Tropospheric Mean Temperature and Cloud-Induced Radiative Fluxes on Intraseasonal Time Scales

    Science.gov (United States)

    Ramey, Holly S.; Robertson, Franklin R.

    2010-01-01

    Intraseasonal variability of deep convection represents a fundamental mode of variability in the organization of tropical convection. While most studies of intraseasonal oscillations (ISOs) have focused on the spatial propagation and dynamics of convectively coupled circulations, we examine the projection of ISOs on the tropically-averaged temperature and energy budget. The area of interest is the global oceans between 20degN/S. Our analysis then focuses on these questions: (i) How is tropospheric temperature related to tropical deep convection and the associated ice cloud fractional amount (ICF) and ice water path (IWP)? (ii) What is the source of moisture sustaining the convection and what role does deep convection play in mediating the PBL - free atmospheric temperature equilibration? (iii) What affect do convectively generated upper-tropospheric clouds have on the TOA radiation budget? Our methodology is similar to that of Spencer et al., (2007) with some modifications and some additional diagnostics of both clouds and boundary layer thermodynamics. A composite ISO time series of cloud, precipitation and radiation quantities built from nearly 40 events during a six-year period is referenced to the atmospheric temperature signal. The increase of convective precipitation cannot be sustained by evaporation within the domain, implying strong moisture transports into the tropical ocean area. While there is a decrease in net TOA radiation that develops after the peak in deep convective rainfall, there seems little evidence that an "Infrared Iris"- like mechanism is dominant. Rather, the cloud-induced OLR increase seems largely produced by weakened convection with warmer cloud tops. Tropical ISO events offer an accessible target for studying ISOs not just in terms of propagation mechanisms, but on their global signals of heat, moisture and radiative flux feedback processes.

  4. Relationships between cone beam CT value and physical density in image guided radiation therapy

    International Nuclear Information System (INIS)

    Jiang Xiaoqin; Bai Sen; Zhong Renming; Tang Zhiquan; Jiang Qinfeng; Li Tao

    2007-01-01

    Objective: To evaluate the main factors affecting the relationship between physical density and CT value in cone-beam computed tomography(CBCT) for imaging guided radiation therapy(IGRT) by comparing the CT value in the image from cone-beam scanner and from fan-beam (FBCT) scanner of a reference phantom. Methods: A taking-park reference phantom with a set of tissue equivalent inserts was scanned at different energies different fields of view (FOV) for IGRT-CBCT and FBCT. The CT value of every insert was measured and compared. Results: The position of inserts in phantom, the size of phantom, the FOV of scanner and different energies had more effect on the relationships between physical density and the CT value from IGRT-CBCT than those from the normal FBCT. The higher the energy was, the less effect of the position of inserts in phantom, the size of phantom and the FOV of scanner on CT value, and the poorer density contrast was observed. Conclusion: At present, the CT value of IGRT-CBCT is not in the true HU value since the manufacturer has not corrected its number. Therefore, we are not able to use the CT value of CBCT for dose calculation in TPS. (authors)

  5. Transformation of solar radiation in Norway spruce stands into produced biomass - the effect of stand density

    International Nuclear Information System (INIS)

    Marková, I.; Marek, M.V.; Pokorný, R.

    2011-01-01

    The present paper is focused on the assessment of the effects of stand density and leaf area development on radiation use efficiency in the mountain cultivated Norway spruce stand. The young even-aged (17-years-old in 1998) plantation of Norway spruce was divided into two experimental plots differing in their stand density in 1995. During the late spring of 2001 next cultivating high-type of thinning of 15% intensity in a reduction of stocking density was performed. The PAR regime of investigated stands was continually measured since 1992. Total aboveground biomass (TBa) and TBa increment were obtained on the basis of stand inventory. The dynamic of LAI development showed a tendency to be saturated, i.e. the LAI value close to 11 seems to be maximal for the local conditions of the investigated mountain cultivated Norway spruce stand in the Beskids Mts. Remarkable stimuli (up to 17%) of LAI formation were started in 2002, i.e. as an immediate response to thinning. Thus, the positive effect of thinning on LAI increase was confirmed. The data set of absorbed PAR and produced TBa in the period 1998-2003 was processed by the linear regression of Monteith's model, which provided the values of the coefficient of solar energy conversion efficiency into biomass formation. The differences in biomass formation values between the dense and sparse plot after thinning amounted to 18%

  6. Radiation Dosimetry of the Pressure Vessel Internals of the High Flux Beam Reactor

    Science.gov (United States)

    Holden, Norman E.; Reciniello, Richard N.; Hu, Jih-Perng; Rorer, David C.

    2003-06-01

    In preparation for the eventual decommissioning of the High Flux Beam Reactor after the permanent removal of its fuel elements from the Brookhaven National Laboratory, both measurements and calculations of the decay gamma-ray dose rate have been performed for the reactor pressure vessel and vessel internal structures which included the upper and lower thermal shields, the Transition Plate, and the Control Rod blades. The measurements were made using Red Perspex™ polymethyl methacrylate high-level film dosimeters, a Radcal "peanut" ion chamber, and Eberline's high-range ion chamber. To compare with measured gamma-ray dose rates, the Monte Carlo MCNP code and geometric progressive MicroShield code were used to model the gamma-ray transport and dose buildup.

  7. RADIATION DOSIMETRY OF THE PRESSURE VESSEL INTERNALS OF THE HIGH FLUX BEAM REACTOR

    International Nuclear Information System (INIS)

    HOLDEN, N.E.; RECINIELLO, R.N.; HU, J.P.; RORER, D.C.

    2002-01-01

    In preparation for the eventual decommissioning of the High Flux Beam Reactor after the permanent removal of its fuel elements from the Brookhaven National Laboratory, both measurements and calculations of the decay gamma-ray dose rate have been performed for the reactor pressure vessel and vessel internal structures which included the upper and lower thermal shields, the transition plate, and the control rod blades. The measurements were made using Red Perspex(trademark) polymethyl methacrylate high-level film dosimeters, a Radcal ''peanut'' ion chamber, and Eberline's high-range ion chamber. To compare with measured gamma-ray dose rate, the Monte Carlo MCNP code and geometric progressive Microshield code were used to model the gamma transport and dose buildup

  8. Evaluation of the Anisotropic Radiative Conductivity of a Low-Density Carbon Fiber Material from Realistic Microscale Imaging

    Science.gov (United States)

    Nouri, Nima; Panerai, Francesco; Tagavi, Kaveh A.; Mansour, Nagi N.; Martin, Alexandre

    2015-01-01

    The radiative heat transfer inside a low-density carbon fiber insulator is analyzed using a three-dimensional direct simulation model. A robust procedure is presented for the numerical calculation of the geometric configuration factor to compute the radiative energy exchange processes among the small discretized surface areas of the fibrous material. The methodology is applied to a polygonal mesh of a fibrous insulator obtained from three-dimensional microscale imaging of the real material. The anisotropic values of the radiative conductivity are calculated for that geometry. The results yield both directional and thermal dependence of the radiative conductivity.

  9. Estimating surface longwave radiative fluxes from satellites utilizing artificial neural networks

    Science.gov (United States)

    Nussbaumer, Eric A.; Pinker, Rachel T.

    2012-04-01

    A novel approach for calculating downwelling surface longwave (DSLW) radiation under all sky conditions is presented. The DSLW model (hereafter, DSLW/UMD v2) similarly to its predecessor, DSLW/UMD v1, is driven with a combination of Moderate Resolution Imaging Spectroradiometer (MODIS) level-3 cloud parameters and information from the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim model. To compute the clear sky component of DSLW a two layer feed-forward artificial neural network with sigmoid hidden neurons and linear output neurons is implemented; it is trained with simulations derived from runs of the Rapid Radiative Transfer Model (RRTM). When computing the cloud contribution to DSLW, the cloud base temperature is estimated by using an independent artificial neural network approach of similar architecture as previously mentioned, and parameterizations. The cloud base temperature neural network is trained using spatially and temporally co-located MODIS and CloudSat Cloud Profiling Radar (CPR) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) observations. Daily average estimates of DSLW from 2003 to 2009 are compared against ground measurements from the Baseline Surface Radiation Network (BSRN) giving an overall correlation coefficient of 0.98, root mean square error (rmse) of 15.84 W m-2, and a bias of -0.39 W m-2. This is an improvement over an earlier version of the model (DSLW/UMD v1) which for the same time period has an overall correlation coefficient 0.97 rmse of 17.27 W m-2, and bias of 0.73 W m-2.

  10. Nimbus-7 Earth radiation budget calibration history. Part 2: The Earth flux channels

    Science.gov (United States)

    Kyle, H. Lee; Hucek, Douglas Richard R.; Ardanuy, Philip E.; Hickey, John R.; Maschhoff, Robert H.; Penn, Lanning M.; Groveman, Brian S.; Vallette, Brenda J.

    1994-01-01

    Nine years (November 1978 to October 1987) of Nimbus-7 Earth radiation budget (ERB) products have shown that the global annual mean emitted longwave, absorbed shortwave, and net radiation were constant to within about + 0.5 W/sq m. Further, most of the small annual variations in the emitted longwave have been shown to be real. To obtain this measurement accuracy, the wide-field-of-view (WFOV) Earth-viewing channels 12 (0.2 to over 50 micrometers), 13 (0.2 to 3.8 micrometers), and 14 (0.7 to 2.8 micrometers) have been characterized in their satellite environment to account for signal variations not considered in the prelaunch calibration equations. Calibration adjustments have been derived for (1) extraterrestrial radiation incident on the detectors, (2) long-term degradation of the sensors, and (3) thermal perturbations within the ERB instrument. The first item is important in all the channels; the second, mainly in channels 13 and 14, and the third, only in channels 13 and 14. The Sun is used as a stable calibration source to monitor the long-term degradation of the various channels. Channel 12, which is reasonably stable to both thermal perturbations and sensor degradation, is used as a reference and calibration transfer agent for the drifting sensitivities of the filtered channels 13 and 14. Redundant calibration procedures were utilized. Laboratory studies complemented analyses of the satellite data. Two nearly independent models were derived to account for the thermal perturbations in channels 13 and 14. The global annual mean terrestrial shortwave and longwave signals proved stable enough to act as secondary calibration sources. Instantaneous measurements may still, at times, be in error by as much as a few Wm(exp -2), but the long-term averages are stable to within a fraction of a Wm(exp -2).

  11. Feasibility study of the plasma electron density measurement by electromagnetic radiation from the laser-driven plasma wave

    International Nuclear Information System (INIS)

    Jang, D G; Kim, J J; Suk, H; Hur, M S

    2012-01-01

    When an intense laser beam is focused in a plasma, a plasma wake wave is generated and the oscillatary motion of the plasma electrons produces a strong electromagnetic wave by a Cherenkov-like process. Spectrum of the genetated electromagnetic wave has dependence on the plasma density. In this paper, we propose to use the emitted electromagnetic radiation for plasma diagnostic, which may provide an accurate information for local electron densities of the plasma and will be very useful for three-dimensional plasma density profiles by changing the focal point location of the laser beam. Two-dimensional (2-D) particle-in-cell (PIC) simulation is used to study the correlation between the spectrum of the emitted radiation and plasma density, and the results demonstrate that this method is promising for the electron density measurement in the plasma.

  12. Effect of vertically aligned carbon nanotube density on the water flux and salt rejection in desalination membranes.

    Science.gov (United States)

    Trivedi, Samarth; Alameh, Kamal

    2016-01-01

    In this paper, vertically aligned carbon nanotube (VACNT) membranes of different densities are developed and their performances are investigated. VACNT arrays of densities 5 × 10(9), 10(10), 5 × 10(10) and 10(11) tubes cm(-2), are initially grown on 1 cm × 1 cm silicon substrates using chemical vapour deposition. A VACNT membrane is realised by attaching a 300 μm-thick 1 cm × 1 cm VACNT array on silicon to a 4″ glass substrate, applying polydimethylsiloxane (PDMS) through spin coating to fill the gaps between the VACNTs, and using a microtome to slice the VACNT-PDMS composite into 25-μm-thick membranes. Experimental results show that the permeability of the developed VACNT membranes increases with the density of the VACNTs, while the salt rejection is almost independent of the VACNT density. The best measured permeance is attained with a VACNT membrane having a CNT density of 10(11) tubes cm(-2) is 1203 LMH at 1 bar.

  13. Investigation of the properties of the flux and interaction of ultrahigh-energy cosmic rays by the method of local-muon-density spectra

    International Nuclear Information System (INIS)

    Bogdanov, A. G.; Gromushkin, D. M.; Kokoulin, R. P.; Mannocchi, G.; Petrukhin, A. A.; Saavedra, O.; Trinchero, G.; Chernov, D. V.; Shutenko, V. V.; Yashin, I. I.

    2010-01-01

    A new method for studying extensive air showers is considered. The method is based on the phenomenology of the localmuon density. It is shown that measurement ofmuon-density spectra at various zenith angles makes it possible to obtain information about the energy spectrum, mass composition, and interaction of cosmic rays over a broad range of energies (10 15 -10 18 eV) by using a single array of comparatively small size. The results obtained from a comparison of experimental data on muon bundles from the DECOR coordinate detector with the results of simulation performed under various assumptions on the properties of the primary flux and for various hadron-interaction models are presented, and possible versions of the interpretation of these results are discussed.

  14. A comparison of radiometric fluxes influenced by parameterization cirrus clouds with observed fluxes at the Southern Great Plains (SGP) cloud and radiation testbed (CART) site

    Energy Technology Data Exchange (ETDEWEB)

    Mace, G.G.; Ackerman, T.P.; George, A.T. [Penn State Univ., University Park, PA (United States)

    1996-04-01

    The data from the Atmospheric Radiation Measurement (ARM) Program`s Southern Great plains Site (SCP) is a valuable resource. We have developed an operational data processing and analysis methodology that allows us to examine continuously the influence of clouds on the radiation field and to test new and existing cloud and radiation parameterizations.

  15. Parallel Jacobian-free Newton Krylov solution of the discrete ordinates method with flux limiters for 3D radiative transfer

    International Nuclear Information System (INIS)

    Godoy, William F.; Liu Xu

    2012-01-01

    The present study introduces a parallel Jacobian-free Newton Krylov (JFNK) general minimal residual (GMRES) solution for the discretized radiative transfer equation (RTE) in 3D, absorbing, emitting and scattering media. For the angular and spatial discretization of the RTE, the discrete ordinates method (DOM) and the finite volume method (FVM) including flux limiters are employed, respectively. Instead of forming and storing a large Jacobian matrix, JFNK methods allow for large memory savings as the required Jacobian-vector products are rather approximated by semiexact and numerical formulations, for which convergence and computational times are presented. Parallelization of the GMRES solution is introduced in a combined memory-shared/memory-distributed formulation that takes advantage of the fact that only large vector arrays remain in the JFNK process. Results are presented for 3D test cases including a simple homogeneous, isotropic medium and a more complex non-homogeneous, non-isothermal, absorbing–emitting and anisotropic scattering medium with collimated intensities. Additionally, convergence and stability of Gram–Schmidt and Householder orthogonalizations for the Arnoldi process in the parallel GMRES algorithms are discussed and analyzed. Overall, the introduction of JFNK methods results in a parallel, yet scalable to the tested 2048 processors, and memory affordable solution to 3D radiative transfer problems without compromising the accuracy and convergence of a Newton-like solution.

  16. Proposal of C-core Type Transverse Flux Motor for Ship Propulsion – Increasing Torque Density by Dense Stator Configuration –

    Directory of Open Access Journals (Sweden)

    Y. Yamamoto

    2014-02-01

    Full Text Available Electric ship propulsion system has been drawing attention as a solution for savings in energy and maintenance costs. The system is mainly composed of motor, converter and gearbox and required for high torque at low speed. In this situation, transverse flux motors (TFMs have been proposed to fulfill the low-speed high-torque characteristic due to suitable for short pole pitch and large number of poles to increase torque output. In this trend, we have proposed C-core type motors taking advantage of TFMs’ structure. In this manuscript, a simple design method based on the magnetic-circuit theory and simple modeling of the motor is proposed to search a design parameter for maximizing torque as a pre-process of numerical study. The method takes into consideration the effects of magnetic leakage flux, magnetic saturation and pole-core combination in accordance with the systematic theory. The simple modeling is conducted based on a dense armature structure in previous axial flux motors (AFMs applied to the new motor design. The validity of the method is verified by 3-D finite element analysis (FEA and relative error is at most 20%. The minimalist design is shown to be advantageous for effective use in 3-D FEA. As a detailed design by the FEA, high torque density and low cogging to output ratio can be achieved simultaneously in the proposed machine.

  17. Design and Implementation of a Detector for High Flux Mixed Radiation Fields

    CERN Document Server

    Kramer, Daniel; Sulc, Miroslav

    2008-01-01

    The main purpose of the LHC Beam Loss Monitoring (BLM) system is the active protection of the LHC accelerators' elements against the quench of superconducting magnets and the damage of equipment caused by the loss of circulating protons. The lost protons initiate a shower of secondary particles, which deposit their energy in the equipment and partly in a radiation detector. If thresholds in the BLM system are exceeded, the circulating LHC beam is directed towards a dump to stop the energy deposition in the fragile equipment. The LHC BLM system will use ionization chambers as standard detectors, and in the areas with very high dose rates Secondary Emission Monitor (SEM) chambers will be employed to increase the dynamic range. The SEM is characterized by a high linearity and accuracy, low sensitivity, fast response and a good radiation tolerance. The emission of electrons from the surface layer of metals by the passage of charged particles is only measurable in a vacuum environment. This requirement leads toget...

  18. Applications of high order harmonic radiation to UVX-solids interaction: high excitation density in electronic relaxation dynamics and surface damaging

    International Nuclear Information System (INIS)

    De Grazia, M.

    2007-12-01

    The new sources of radiation in the extreme-UV (X-UV: 10-100 nm), which deliver spatially coherent, ultra-short and intense pulses, allow studying high flux processes and ultra-fast dynamics in various domains. The thesis work presents two applications of the high-order laser harmonics (HH) to solid state physics. In Part I, we describe the optimization of the harmonic for studies of X-UV/solids interaction. In Part II, we investigate effects of high excitation density in the dynamics of electron relaxation in dielectric scintillator crystals - tungstates and fluorides, using time-resolved luminescence spectroscopy. Quenching of luminescence at short time gives evidence of the competition between radiative and non-radiative recombination of self-trapped excitons (STE). The non-radiative channel is identified to mutual interaction of STE at high excitation density. In Part III, we study the X-UV induced damage mechanism in various materials, either conductor (amorphous carbon) or insulators (organic polymers, e.g., PMMA). In PMMA-Plexiglas, in the desorption regime (0.2 mJ/cm 2 , i.e., below damage threshold), the surface modifications reflect X-UV induced photochemical processes that are tentatively identified, as a function of dose: at low dose, polymer chain scission followed by the blow-up of the volatile, low-molecular fragments leads to crater formation; at high dose, cross-linking in the near-surface layer of remaining material leads to surface hardening. These promising results have great perspectives considering the performances already attained and planned in the next future in the development of the harmonic sources. (author)

  19. Poloidal density variation of impurities in a rotating tokamak plasma - flux surface coordinates and effect on transport coefficients

    International Nuclear Information System (INIS)

    Romanelli, M.

    1999-09-01

    The poloidal variation of impurity densities over magnetic surfaces brings about an enhancement of neoclassical transport coefficients, as shown by Romanelli and Ottaviani for impurities in the Pfirsch Schlueter regime and by Helander for particles in the banana-plateau regime, both in a large aspect ratio tokamak. The same effect will occur in a finite aspect ratio tokamak and therefore it is considered to be relevant for inclusion in transport codes for comparison with the experimental measurements of impurity transport. Here an expression for the impurity-density poloidal-variation generated by the fast toroidal rotation of the plasma column is presented in general coordinates. (author)

  20. The Positronium Radiative Combination Spectrum: Calculation in the Limit of Thermal Positrons and Low Densities

    Science.gov (United States)

    Wallyn, P.; Mahoney, W. A.; Durouchoux, Ph.; Chapuis, C.

    1996-01-01

    We calculate the intensities of the positronium de-excitation lines for two processes: (1) the radiative combination of free thermal electrons and positrons for transitions with principal quantum number n less than 20, and (2) charge exchange between free positrons and hydrogen and helium atoms, restricting our evaluation to the Lyman-alpha line. We consider a low-density medium modeled by the case A assumption of Baker & Menzel and use the "nL method" of Pengelly to calculate the absolute intensities. We also evaluate the positronium fine and hyperfine intensities and show that these transitions are in all cases much weaker than positronium de-excitation lines in the same wavelength range. We also extrapolate our positronium de-excitation intensities to the submillimeter, millimeter, and centimeter wavelengths. Our results favor the search of infrared transitions of positronium lines for point sources when the visual extinction A, is greater than approx. 5.

  1. The hydrodynamic and radiative properties of low-density foams heated by x-rays

    Czech Academy of Sciences Publication Activity Database

    Rosmej, O. N.; Suslov, N.; Martsovenko, D.; Vergunova, G.; Borisenko, N.; Orlov, N.; Rienecker, T.; Klír, Daniel; Řezáč, Karel; Orekhov, A.; Borisenko, L.; Krouský, Eduard; Pfeifer, Miroslav; Dudžák, Roman; Maeder, R.; Schaechinger, M.; Schoenlein, A.; Zaehter, S.; Jacoby, J.; Limpouch, J.; Ullschmied, Jiří; Zhidkov, N.

    2015-01-01

    Roč. 57, č. 9 (2015), č. článku 094001. ISSN 0741-3335 R&D Projects: GA MŠk(CZ) LG13029; GA MŠk LM2010014 Grant - others:FP7(XE) 284464 Program:FP7 Institutional support: RVO:61389021 Keywords : hohlraum * low density polymer aerogel * opacity * Planckian radiation * plasma * x-rays Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.404, year: 2015 http://iopscience.iop.org/article/10.1088/0741-3335/57/9/094001;jsessionid=E4079D2364DFCC5CA64FBF3B9F73D180.c2.iopscience.cld.iop.org

  2. Ultra-High Density Electron Beams for Beam Radiation and Beam Plasma Interaction

    CERN Document Server

    Anderson, Scott; Frigola, Pedro; Gibson, David J; Hartemann, Fred V; Jacob, Jeremy S; Lim, Jae; Musumeci, Pietro; Rosenzweig, James E; Travish, Gil; Tremaine, Aaron M

    2005-01-01

    Current and future applications of high brightness electron beams, which include advanced accelerators such as the plasma wake-field accelerator (PWFA) and beam-radiation interactions such as inverse-Compton scattering (ICS), require both transverse and longitudinal beam sizes on the order of tens of microns. Ultra-high density beams may be produced at moderate energy (50 MeV) by compression and subsequent strong focusing of low emittance, photoinjector sources. We describe the implementation of this method used at LLNL's PLEIADES ICS x-ray source in which the photoinjector-generated beam has been compressed to 300 fsec duration using the velocity bunching technique and focused to 20 μm rms size using an extremely high gradient, permanent magnet quadrupole (PMQ) focusing system.

  3. Research on transition undulator radiation

    International Nuclear Information System (INIS)

    Lu Shuzhuang; Dai Zhimin; Zhao Xiaofeng

    2000-01-01

    The theory of transition undulator radiation was described first, then the properties of infrared and far-infrared transition undulator radiation of SSRF U9.0 were explored by the methods of analytical treatment and numerical simulation, and the influence of beam energy spread, emittance, and magnetic field errors on transition undulator radiation was given also. It was shown that the flux density of the infrared and far-infrared transition undulator radiation of the SSRF U9.0 was high (e.g., the maximum flux density might reach 35 x 10 13 photons/(s·mrad 2 ·BW), collecting angle φ = 0.23 mrad, and the effects of beam energy spread, emittance and magnetic field errors on the radiation flux density were small

  4. Natural fibre high-density polyethylene and lead oxide composites for radiation shielding

    CERN Document Server

    El-Sayed, A; Ismail, M R

    2003-01-01

    Study has been made of the radiation shielding provided by recycled agricultural fibre and industrial plastic wastes produced as composite materials. Fast neutron and gamma-ray spectra behind composites of fibre-plastic (rho = 1.373 g cm sup - sup 3) and fibre-plastic-lead (rho = 2.756 g cm sup - sup 3) have been measured using a collimated reactor beam and neutron-gamma spectrometer with a stilbene scintillator. The pulse shape discriminating technique based on the zero-cross-over method was used to discriminate between neutron and gamma-ray pulses. Slow neutron fluxes have been measured using a collimated reactor beam and BF sub 3 counter, leading to determination of the macroscopic cross-section (SIGMA). The removal cross-sections (SIGMA sub R) of fast neutrons have been determined from measured results and elemental composition of the composites. For gamma-rays, total linear attenuation coefficients (mu) and total mass attenuation coefficients (mu/rho) have been determined from use of the XCOM code and me...

  5. Constraining the cosmic radiation density due to lepton number with Big Bang Nucleosynthesis

    International Nuclear Information System (INIS)

    Mangano, Gianpiero; Miele, Gennaro; Pisanti, Ofelia; Sarikas, Srdjan; Pastor, Sergio

    2011-01-01

    The cosmic energy density in the form of radiation before and during Big Bang Nucleosynthesis (BBN) is typically parameterized in terms of the effective number of neutrinos N eff . This quantity, in case of no extra degrees of freedom, depends upon the chemical potential and the temperature characterizing the three active neutrino distributions, as well as by their possible non-thermal features. In the present analysis we determine the upper bounds that BBN places on N eff from primordial neutrino-antineutrino asymmetries, with a careful treatment of the dynamics of neutrino oscillations. We consider quite a wide range for the total lepton number in the neutrino sector, η ν = η ν e +η ν μ +η ν τ and the initial electron neutrino asymmetry η ν e in , solving the corresponding kinetic equations which rule the dynamics of neutrino (antineutrino) distributions in phase space due to collisions, pair processes and flavor oscillations. New bounds on both the total lepton number in the neutrino sector and the ν e −ν-bar e asymmetry at the onset of BBN are obtained fully exploiting the time evolution of neutrino distributions, as well as the most recent determinations of primordial 2 H/H density ratio and 4 He mass fraction. Note that taking the baryon fraction as measured by WMAP, the 2 H/H abundance plays a relevant role in constraining the allowed regions in the η ν −η ν e in plane. These bounds fix the maximum contribution of neutrinos with primordial asymmetries to N eff as a function of the mixing parameter θ 13 , and point out the upper bound N eff ∼ eff by the Planck satellite will likely provide insight on the nature of the radiation content of the universe

  6. Constraining the cosmic radiation density due to lepton number with Big Bang Nucleosynthesis

    Science.gov (United States)

    Mangano, Gianpiero; Miele, Gennaro; Pastor, Sergio; Pisanti, Ofelia; Sarikas, Srdjan

    2011-03-01

    The cosmic energy density in the form of radiation before and during Big Bang Nucleosynthesis (BBN) is typically parameterized in terms of the effective number of neutrinos Neff. This quantity, in case of no extra degrees of freedom, depends upon the chemical potential and the temperature characterizing the three active neutrino distributions, as well as by their possible non-thermal features. In the present analysis we determine the upper bounds that BBN places on Neff from primordial neutrino-antineutrino asymmetries, with a careful treatment of the dynamics of neutrino oscillations. We consider quite a wide range for the total lepton number in the neutrino sector, ην = ηνe+ηνμ+ηντ and the initial electron neutrino asymmetry ηνein, solving the corresponding kinetic equations which rule the dynamics of neutrino (antineutrino) distributions in phase space due to collisions, pair processes and flavor oscillations. New bounds on both the total lepton number in the neutrino sector and the νe-bar nue asymmetry at the onset of BBN are obtained fully exploiting the time evolution of neutrino distributions, as well as the most recent determinations of primordial 2H/H density ratio and 4He mass fraction. Note that taking the baryon fraction as measured by WMAP, the 2H/H abundance plays a relevant role in constraining the allowed regions in the ην-ηνein plane. These bounds fix the maximum contribution of neutrinos with primordial asymmetries to Neff as a function of the mixing parameter θ13, and point out the upper bound Nefflesssim3.4. Comparing these results with the forthcoming measurement of Neff by the Planck satellite will likely provide insight on the nature of the radiation content of the universe.

  7. On the use of flux limiters in the discrete ordinates method for 3D radiation calculations in absorbing and scattering media

    International Nuclear Information System (INIS)

    Godoy, William F.; DesJardin, Paul E.

    2010-01-01

    The application of flux limiters to the discrete ordinates method (DOM), S N , for radiative transfer calculations is discussed and analyzed for 3D enclosures for cases in which the intensities are strongly coupled to each other such as: radiative equilibrium and scattering media. A Newton-Krylov iterative method (GMRES) solves the final systems of linear equations along with a domain decomposition strategy for parallel computation using message passing libraries in a distributed memory system. Ray effects due to angular discretization and errors due to domain decomposition are minimized until small variations are introduced by these effects in order to focus on the influence of flux limiters on errors due to spatial discretization, known as numerical diffusion, smearing or false scattering. Results are presented for the DOM-integrated quantities such as heat flux, irradiation and emission. A variety of flux limiters are compared to 'exact' solutions available in the literature, such as the integral solution of the RTE for pure absorbing-emitting media and isotropic scattering cases and a Monte Carlo solution for a forward scattering case. Additionally, a non-homogeneous 3D enclosure is included to extend the use of flux limiters to more practical cases. The overall balance of convergence, accuracy, speed and stability using flux limiters is shown to be superior compared to step schemes for any test case.

  8. Development of the Radiation Stabilized Distributed Flux Burner - Phase III Final Report

    Energy Technology Data Exchange (ETDEWEB)

    J. D. Sullivan; A. Webb

    1999-12-01

    The development and demonstration of the Radiation Stabilized Burner (RSB) was completed as a project funded by the US Department of Energy Office of Industrial Technologies. The technical goals of the project were to demonstrate burner performance that would meet or exceed emissions targets of 9 ppm NOx, 50 ppm CO, and 9 ppm unburned hydrocarbons (UHC), with all values being corrected to 3 percent stack oxygen, and incorporate the burner design into a new industrial boiler configuration that would achieve ultra-low emissions while maintaining or improving thermal efficiency, operating costs, and maintenance costs relative to current generation 30 ppm low NOx burner installations. Both the ultra-low NOx RSB and the RSB boiler-burner package are now commercially available.

  9. Tracer kinetic studies of the low density lipoprotein metabolism in the fetal rat: An example for estimation of flux rates in the nonsteady state

    International Nuclear Information System (INIS)

    Plonne, D.; Schlag, B.; Winkler, L.; Dargel, R.

    1990-01-01

    To get insight into the low density lipoprotein (LDL)-apoB flux in the rat fetus near term and in the early postnatal period, homologous apoE-free 125I-labeled LDL was injected into the umbilical vein of the rat fetus immediately after Caesarean section. Since the serum LDL-apoB spontaneously declined after birth, a time-dependent two-pool model was used to calculate the flux rates in the neonate from the specific activities of LDL-apoB up to 15 h post partum. An approximate value of LDL-apoB flux in the fetus at birth was obtained by extrapolation of the kinetic data to the time of injection of the tracer. The data revealed that the turnover of LDL-apoB in the fetus (18.6 micrograms LDL-apoB/h per g body weight) exceeded that in the adult rat (0.4 microgram/h per g body weight) by at least one order of magnitude. Even 15 h after delivery, the LDL-apoB influx amounted to 2.5 micrograms/h per g body weight. The fractional catabolic rate of LDL-apoB in the fetus at term (0.39, h-1) slightly exceeded that in the adult animal (0.15, h-1) and reached the adult level within the first 3 h after birth and remained constant thereafter. In the rat fetus, LDL-apoB flux greatly exceeds that of VLDL-apoB. The data support the view of a direct synthesis and secretion of LDL, most probably by the fetal membranes

  10. Effective radiation attenuation calibration for breast density: compression thickness influences and correction

    Directory of Open Access Journals (Sweden)

    Thomas Jerry A

    2010-11-01

    Full Text Available Abstract Background Calibrating mammograms to produce a standardized breast density measurement for breast cancer risk analysis requires an accurate spatial measure of the compressed breast thickness. Thickness inaccuracies due to the nominal system readout value and compression paddle orientation induce unacceptable errors in the calibration. Method A thickness correction was developed and evaluated using a fully specified two-component surrogate breast model. A previously developed calibration approach based on effective radiation attenuation coefficient measurements was used in the analysis. Water and oil were used to construct phantoms to replicate the deformable properties of the breast. Phantoms consisting of measured proportions of water and oil were used to estimate calibration errors without correction, evaluate the thickness correction, and investigate the reproducibility of the various calibration representations under compression thickness variations. Results The average thickness uncertainty due to compression paddle warp was characterized to within 0.5 mm. The relative calibration error was reduced to 7% from 48-68% with the correction. The normalized effective radiation attenuation coefficient (planar representation was reproducible under intra-sample compression thickness variations compared with calibrated volume measures. Conclusion Incorporating this thickness correction into the rigid breast tissue equivalent calibration method should improve the calibration accuracy of mammograms for risk assessments using the reproducible planar calibration measure.

  11. Characterization of radiation-cross-linked, high-density polyethylene for thermal energy storage

    International Nuclear Information System (INIS)

    Whitaker, R.B.; Craven, S.M.; Etter, D.E.; Jendrek, E.F.; Nease, A.B.

    1983-01-01

    Electron beam cross-linked high-density polyethylene (HDPE) pellets (DuPont Alathon, 0.93 MI) have been characterized for potential utility in thermal energy storage applications, before and after up to 500 melt-freeze cycles in ethylene glycol. Up to 95% of the HDPE's initial DSC differential scanning calorimetry Δ H/sub f/ value (44.7 cal/g) (at 1.25 0 C/min cooling rates) was retained up to 9.0 Mrad radiation dosage. Form-stability after 500 melt-freeze cycles was very good at this dosage level. X-ray diffraction measurements showed little difference between irradiated HDPE's and the unirradiated control, indicating that cross-linking occurred primarily in the amorphous regions. FTIR spectroscopy showed the pellets to be uniformly reacted. The ratios of the 965-cm -1 absorption band (trans RCH=CRH') to the 909-cm -1 band (RCH=CH 2 ) increased with increasing radiation dosage, up to 18 Mrad. Gel contents reached a maximum of 75% at the 13.5 Mrad dosage, indicating that other reactions, in addition to cross-linking, occurred at the highest (18 Mrad) dosage level. 15 references, 5 figures, 4 tables

  12. Radiation-assisted grafting of vinylidene chloride onto high-density polyethylene

    Science.gov (United States)

    Nagesh, N.; Dokhale, P. A.; Bhoraskar, V. N.

    1999-06-01

    6 MeV electrons and Co-60 icons/Journals/Common/gamma" ALT="gamma" ALIGN="TOP"/>-rays were used for grafting vinylidene chloride (VDC) onto high-density polyethylene (HDPE) samples. The HDPE samples were immersed in vinylidene chloride and irradiated either with Co-60 icons/Journals/Common/gamma" ALT="gamma" ALIGN="TOP"/>-rays or with 6 MeV electrons. In both cases, the radiation dose was varied in the range 1.25-7.5 kGy. The grafted samples were characterized by IR spectroscopy to obtain information about the chemical bonds and with the 14 MeV neutron activation analysis technique for estimating the number of chlorine atoms. The formation of stable bonds between the VDC molecules and the polymer chains could be achieved either with 6 MeV electrons or with Co-60 icons/Journals/Common/gamma" ALT="gamma" ALIGN="TOP"/>-rays. Both the number of chlorine atoms and the sample-surface conductivity increased with the radiation dose but the increases achieved with 6 MeV electrons were greater than those achieved with Co-60 icons/Journals/Common/gamma" ALT="gamma" ALIGN="TOP"/>-rays.

  13. Terrestrial gamma radiation baseline mapping using ultra low density sampling methods.

    Science.gov (United States)

    Kleinschmidt, R; Watson, D

    2016-01-01

    Baseline terrestrial gamma radiation maps are indispensable for providing basic reference information that may be used in assessing the impact of a radiation related incident, performing epidemiological studies, remediating land contaminated with radioactive materials, assessment of land use applications and resource prospectivity. For a large land mass, such as Queensland, Australia (over 1.7 million km(2)), it is prohibitively expensive and practically difficult to undertake detailed in-situ radiometric surveys of this scale. It is proposed that an existing, ultra-low density sampling program already undertaken for the purpose of a nationwide soil survey project be utilised to develop a baseline terrestrial gamma radiation map. Geoelement data derived from the National Geochemistry Survey of Australia (NGSA) was used to construct a baseline terrestrial gamma air kerma rate map, delineated by major drainage catchments, for Queensland. Three drainage catchments (sampled at the catchment outlet) spanning low, medium and high radioelement concentrations were selected for validation of the methodology using radiometric techniques including in-situ measurements and soil sampling for high resolution gamma spectrometry, and comparative non-radiometric analysis. A Queensland mean terrestrial air kerma rate, as calculated from the NGSA outlet sediment uranium, thorium and potassium concentrations, of 49 ± 69 nGy h(-1) (n = 311, 3σ 99% confidence level) is proposed as being suitable for use as a generic terrestrial air kerma rate background range. Validation results indicate that catchment outlet measurements are representative of the range of results obtained across the catchment and that the NGSA geoelement data is suitable for calculation and mapping of terrestrial air kerma rate. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  14. Influences of radiation and leaf area vertical distribution on the growth of Chinese fir young plantation with different densities

    International Nuclear Information System (INIS)

    Wang Lili

    1990-01-01

    A study on the radiation and leaf area vertical distribution in relation to the growth of 8-year-old Chinese fir plantations of 5 densities was conducted. The leaf area vertical distribution and LAI were closely related to stem density. The crown form varies from conic to cylindric with the increase of stem density. The LAI rises at first and then declines with the increase of density. The extinction of radiation sharpened when the crown density increased. The extinction leveled at the depth of 3/4 forest heights from the tops of forest canopies. Calculating the extinction coefficients by means of accumulated leaf area index separately for each crown layer can minimize the errors caused by the irregularity of leaf distribution. Four indices, i.e., absorption of radiation, LAI,biomass of individual tree and averaged annual increment of biomass were used to have a comprehensive evaluation on the growth of Chinese fir of 5 densities. The results showed that the plantation with a stem density of 2m × 1 m was the best one among the 5 young plantations

  15. Measurement system study using beta radiation for determining different paper superficial density

    International Nuclear Information System (INIS)

    Vieira, Thais Molina; Madi Filho, Tufic

    2000-01-01

    Radioisotopes are used now in some areas of the industry. For quality control purposes, they are used in non-destructive analysis (NDA) which is applied to the materials examination verifying if they are adequate to the patterns demanded by technical rules or the market. Gamma, beta or neutron radiation sources may be used to do NDA, depending on material to be analyzed and the industrial process. In this work, the study of measurement system applied to quality control area was conceived and, in the evaluation of the material in test, a radioactive beta source was used. A system was designed and mounted, using a plastic scintillator detector developed in the laboratories of the Centro de Tecnologia das Radiacoes from IPEN-CNEN/SP. Two beta sources were used in the operational test: 90 Sr/ 90 Y and 204 Tl. Measures were obtained using several paper samples with different superficial density in g/m 2 . With the results, an equation correlating the relative activity with the superficial density in g/m 2 was established. (author)

  16. Radiative corrections in supersymmetry and application to relic density calculation beyond leading order

    International Nuclear Information System (INIS)

    Chalons, G.

    2010-07-01

    This thesis focuses on the evaluation of supersymmetric radiative corrections for processes involved in the calculation of the relic density of dark matter, in the MSSM (Minimal Supersymmetric Standard Model) and the standard cosmological scenario, as well as the impact of the choice renormalisation scheme in the neutralino/chargino sector based on the measure of three physical masses. This study has been carried out with the help of an automatic program dedicated the the computation of physical observables at one-loop in the MSSM, called SloopS. For the relic density calculation we investigated scenarios where the most studied dark matter candidate, the neutralino, annihilates into gauge boson pair. We covered cases where its mass was of the order of hundreds of GeV to 2 TeV. The full set of electroweak and strong corrections has been taken into account, involved in sub-leading channels with quarks. In the case of very heavy neutralinos, two important effects were outlined: the Sommerfeld enhancement due to massive gauge bosons and maybe even more important some corrections of Sudakov type. (authors)

  17. Variations of the Electron Fluxes in the Terrestrial Radiation Belts Due To the Impact of Corotating Interaction Regions and Interplanetary Coronal Mass Ejections

    Science.gov (United States)

    Benacquista, R.; Boscher, D.; Rochel, S.; Maget, V.

    2018-02-01

    In this paper, we study the variations of the radiation belts electron fluxes induced by the interaction of two types of solar wind structures with the Earth magnetosphere: the corotating interaction regions and the interplanetary coronal mass ejections. We use a statistical method based on the comparison of the preevent and postevent fluxes. Applied to the National Oceanic and Atmospheric Administration-Polar Operational Environmental Satellites data, this gives us the opportunity to extend previous studies focused on relativistic electrons at geosynchronous orbit. We enlighten how corotating interaction regions and Interplanetary Coronal Mass Ejections can impact differently the electron belts depending on the energy and the L shell. In addition, we provide a new insight concerning these variations by considering their amplitude. Finally, we show strong relations between the intensity of the magnetic storms related to the events and the variation of the flux. These relations concern both the capacity of the events to increase the flux and the deepness of these increases.

  18. Comparison of mesoscale model and tower measurements of surface fluxes during Winter Icing and Storms Program/Atmospheric Radiation Measurement 91

    International Nuclear Information System (INIS)

    Oncley, S.P.; Dudhia, J.

    1994-01-01

    This study is an evaluation of the ability of the Pennsylvania State University/National Center for Atmospheric Research (NCAR) mesoscale model (MM4) to determine surface fluxes to see if measured fluxes should be assimilated into model runs. Fluxes were compared from a high-resolution (5 km grid spacing) MM4 run during one day of the Winter Icing and Storms Programs/Atmospheric Radiation Measurement (WISP/ARM) experiment (over NE Colorado in winter 1991) with direct flux measurements made from a tower over a representative site by a three-dimensional sonic anemometer and fast response temperature and humidity sensors. This tower was part of the NCAR Atmosphere-Surface Turbulent Exchange Research (ASTER) facility. Also, mean values were compared to check whether any differences were due to the model parameterization or model variables

  19. Recording of radiation-induced optical density changes in doped agarose gels with a CCD camera

    International Nuclear Information System (INIS)

    Tarte, B.J.; Jardine, P.A.; Van Doorn, T.

    1996-01-01

    Full text: Spatially resolved dose measurement with iron-doped agarose gels is continuing to be investigated for applications in radiotherapy dosimetry. It has previously been proposed to use optical methods, rather than MRI, for dose measurement with such gels and this has been investigated using a spectrophotometer (Appleby A and Leghrouz A, Med Phys, 18:309-312, 1991). We have previously studied the use of a pencil beam laser for such optical density measurement of gels and are currently investigating charge-coupled devices (CCD) camera imaging for the same purpose but with the advantages of higher data acquisition rates and potentially greater spatial resolution. The gels used in these studies were poured, irradiated and optically analysed in Perspex casts providing gel sections 1 cm thick and up to 20 cm x 30 cm in dimension. The gels were also infused with a metal indicator dye (xylenol orange) to render the radiation induced oxidation of the iron in the gel sensitive to optical radiation, specifically in the green spectral region. Data acquisition with the CCD camera involved illumination of the irradiated gel section with a diffuse white light source, with the light from the plane of the gel section focussed to the CCD array with a manual zoom lens. The light was also filtered with a green colour glass filter to maximise the contrast between unirradiated and irradiated gels. The CCD camera (EG and G Reticon MC4013) featured a 1024 x 1024 pixel array and was interfaced to a PC via a frame grabber acquisition board with 8 bit resolution. The performance of the gel dosimeter was appraised in mapping of physical and dynamic wedged 6 MV X-ray fields. The results from the CCD camera detection system were compared with both ionisation chamber data and laser based optical density measurements of the gels. Cross beam profiles were extracted from each measurement system at a particular depth (eg. 2.3 cm for the physical wedge field) for direct comparison. A

  20. Terrestrial gamma radiation baseline mapping using ultra low density sampling methods

    International Nuclear Information System (INIS)

    Kleinschmidt, R.; Watson, D.

    2016-01-01

    Baseline terrestrial gamma radiation maps are indispensable for providing basic reference information that may be used in assessing the impact of a radiation related incident, performing epidemiological studies, remediating land contaminated with radioactive materials, assessment of land use applications and resource prospectivity. For a large land mass, such as Queensland, Australia (over 1.7 million km 2 ), it is prohibitively expensive and practically difficult to undertake detailed in-situ radiometric surveys of this scale. It is proposed that an existing, ultra-low density sampling program already undertaken for the purpose of a nationwide soil survey project be utilised to develop a baseline terrestrial gamma radiation map. Geoelement data derived from the National Geochemistry Survey of Australia (NGSA) was used to construct a baseline terrestrial gamma air kerma rate map, delineated by major drainage catchments, for Queensland. Three drainage catchments (sampled at the catchment outlet) spanning low, medium and high radioelement concentrations were selected for validation of the methodology using radiometric techniques including in-situ measurements and soil sampling for high resolution gamma spectrometry, and comparative non-radiometric analysis. A Queensland mean terrestrial air kerma rate, as calculated from the NGSA outlet sediment uranium, thorium and potassium concentrations, of 49 ± 69 nGy h −1 (n = 311, 3σ 99% confidence level) is proposed as being suitable for use as a generic terrestrial air kerma rate background range. Validation results indicate that catchment outlet measurements are representative of the range of results obtained across the catchment and that the NGSA geoelement data is suitable for calculation and mapping of terrestrial air kerma rate. - Highlights: • A baseline terrestrial air kerma map of Queensland, Australia was developed using geochemical data from a major drainage catchment ultra-low density sampling program

  1. Computed tomography as a source of electron density information for radiation treatment planning

    International Nuclear Information System (INIS)

    Skrzynski, Witold; Slusarczyk-Kacprzyk, Wioletta; Bulski, Wojciech; Zielinska-Dabrowska, Sylwia; Wachowicz, Marta; Kukolowicz, Pawel F.

    2010-01-01

    Purpose: to evaluate the performance of computed tomography (CT) systems of various designs as a source of electron density (ρ el ) data for treatment planning of radiation therapy. Material and methods: dependence of CT numbers on relative electron density of tissue-equivalent materials (HU-ρ el relationship) was measured for several general-purpose CT systems (single-slice, multislice, wide-bore multislice), for radiotherapy simulators with a single-slice CT and kV CBCT (cone-beam CT) options, as well as for linear accelerators with kV and MV CBCT systems. Electron density phantoms of four sizes were used. Measurement data were compared with the standard HU-ρ el relationships predefined in two commercial treatment-planning systems (TPS). Results: the HU-ρ el relationships obtained with all of the general-purpose CT scanners operating at voltages close to 120 kV were very similar to each other and close to those predefined in TPS. Some dependency of HU values on tube voltage was observed for bone-equivalent materials. For a given tube voltage, differences in results obtained for different phantoms were larger than those obtained for different CT scanners. For radiotherapy simulators and for kV CBCT systems, the information on ρ el was much less precise because of poor uniformity of images. For MV CBCT, the results were significantly different than for kV systems due to the differing energy spectrum of the beam. Conclusion: the HU-ρ el relationships predefined in TPS can be used for general-purpose CT systems operating at voltages close to 120 kV. For nontypical imaging systems (e.g., CBCT), the relationship can be significantly different and, therefore, it should always be measured and carefully analyzed before using CT data for treatment planning. (orig.)

  2. New self-similar radiation-hydrodynamics solutions in the high-energy density, equilibrium diffusion limit

    International Nuclear Information System (INIS)

    Lane, Taylor K; McClarren, Ryan G

    2013-01-01

    This work presents semi-analytic solutions to a radiation-hydrodynamics problem of a radiation source driving an initially cold medium. Our solutions are in the equilibrium diffusion limit, include material motion and allow for radiation-dominated situations where the radiation energy is comparable to (or greater than) the material internal energy density. As such, this work is a generalization of the classical Marshak wave problem that assumes no material motion and that the radiation energy is negligible. Including radiation energy density in the model serves to slow down the wave propagation. The solutions provide insight into the impact of radiation energy and material motion, as well as present a novel verification test for radiation transport packages. As a verification test, the solution exercises the radiation–matter coupling terms and their v/c treatment without needing a hydrodynamics solve. An example comparison between the self-similar solution and a numerical code is given. Tables of the self-similar solutions are also provided. (paper)

  3. Level Densities and Radiative Strength Functions in 56FE and 57FE

    Energy Technology Data Exchange (ETDEWEB)

    Tavukcu, Emel [North Carolina State Univ., Raleigh, NC (United States)

    2002-12-10

    Understanding nuclear level densities and radiative strength functions is important for pure and applied nuclear physics. Recently, the Oslo Cyclotron Group has developed an experimental method to extract level densities and radiative strength functions simultaneously from the primary γ rays after a light-ion reaction. A primary γ-ray spectrum represents the γ-decay probability distribution. The Oslo method is based on the Axel-Brink hypothesis, according to which the primary γ-ray spectrum is proportional to the product of the level density at the final energy and the radiative strength function. The level density and the radiative strength function are fit to the experimental primary γ-ray spectra, and then normalized to known data. The method works well for heavy nuclei. The present measurements extend the Oslo method to the lighter mass nuclei 56Fe and 57Fe. The experimental level densities in 56Fe and 57Fe reveal step structure. This step structure is a signature for nucleon pair breaking. The predicted pairing gap parameter is in good agreement with the step corresponding to the first pair breaking. Thermodynamic quantities for 56Fe and 57Fe are derived within the microcanonical and canonical ensembles using the experimental level densities. Energy-temperature relations are considered using caloric curves and probability density functions. The differences between the thermodynamics of small and large systems are emphasized. The experimental heat capacities are compared with the recent theoretical calculations obtained in the Shell Model Monte Carlo method. Radiative strength functions in 56Fe and 57Fe have surprisingly high values at low γ-ray energies. This behavior has not been observed for heavy nuclei, but has been observed in other light- and medium-mass nuclei. The origin of this low γ-ray energy effect remains unknown.

  4. Component greenhouse gas fluxes and radiative balance from two deltaic marshes in Louisiana: Pairing chamber techniques and eddy covariance

    Science.gov (United States)

    Krauss, Ken W.; Holm, Guerry O.; Perez, Brian C.; McWhorter, David E.; Cormier, Nicole; Moss, Rebecca; Johnson, Darren; Neubauer, Scott C; Raynie, Richard C

    2016-01-01

    Coastal marshes take up atmospheric CO2 while emitting CO2, CH4, and N2O. This ability to sequester carbon (C) is much greater for wetlands on a per-area basis than from most ecosystems, facilitating scientific, political, and economic interest in their value as greenhouse gas sinks. However, the greenhouse gas balance of Gulf of Mexico wetlands is particularly understudied. We describe the net ecosystem exchange (NEEc) of CO2 and CH4 using eddy covariance (EC) in comparison with fluxes of CO2, CH4, and N2O using chambers from brackish and freshwater marshes in Louisiana, USA. From EC, we found that 182 g C m-2 y-1 was lost through NEEc from the brackish marsh. Of this, 11 g C m-2 y-1 resulted from net CH4 emissions and the remaining 171 g C m-2 y-1 resulted from net CO2 emissions. In contrast, -290 g C m2 y-1 was taken up through NEEc by the freshwater marsh, with 47 g C m-2 y-1 emitted as CH4 and -337 g C m-2 y-1 taken up as CO2. From chambers, we discovered that neither site had large fluxes of N2O. Sustained-flux greenhouse gas accounting metrics indicated that both marshes had a positive (warming) radiative balance, with the brackish marsh having a substantially greater warming effect than the freshwater marsh. That net respiratory emissions of CO2 and CH4 as estimated through chamber techniques were 2-4 times different from emissions estimated through EC requires additional understanding of the artifacts created by different spatial and temporal sampling footprints between techniques.

  5. Power spectral density and scaling exponent of high frequency global solar radiation sequences

    Science.gov (United States)

    Calif, Rudy; Schmitt, François G.; Huang, Yongxiang

    2013-04-01

    invariance: Iq(f) ~ f-?(q) , ?(q) is the scaling exponent. This allows to characterize the scaling behavior of a process: fractal or multifractal with intermittent properties. For q = 2, the Hilbert spectrum is defined. In this work, The data are collected at the University site of Guadeloupe, an island in the West Indies, located at 16°15 N latitude 60°30 W longitude. Our measurements sampled at 1 Hz were performed during one year period. The analyzed data present a power spectral density E(f) displaying a power law of the form E(f) ~ f-β with 1.6 ˜ β ˜ 2.2 for frequencies f ˜ 0.1 Hz, corresponding to time scales T × 10 s. Furthermore, global solar radiation data possesses multifractal properties. For comparison, other multifractal analysis techniques such as structure functions, MDFA, wavelet leaders are also used. This preliminary work set the basis for further investigation dedicated to simulate and forecast a sequence of solar energy fluctuation under different meteorological conditions, in the multifractal framework.

  6. Top-down and bottom-up aerosol-cloud closure: towards understanding sources of uncertainty in deriving cloud shortwave radiative flux

    Science.gov (United States)

    Sanchez, Kevin J.; Roberts, Gregory C.; Calmer, Radiance; Nicoll, Keri; Hashimshoni, Eyal; Rosenfeld, Daniel; Ovadnevaite, Jurgita; Preissler, Jana; Ceburnis, Darius; O'Dowd, Colin; Russell, Lynn M.

    2017-08-01

    Top-down and bottom-up aerosol-cloud shortwave radiative flux closures were conducted at the Mace Head Atmospheric Research Station in Galway, Ireland, in August 2015. This study is part of the BACCHUS (Impact of Biogenic versus Anthropogenic emissions on Clouds and Climate: towards a Holistic UnderStanding) European collaborative project, with the goal of understanding key processes affecting aerosol-cloud shortwave radiative flux closures to improve future climate predictions and develop sustainable policies for Europe. Instrument platforms include ground-based unmanned aerial vehicles (UAVs)1 and satellite measurements of aerosols, clouds and meteorological variables. The ground-based and airborne measurements of aerosol size distributions and cloud condensation nuclei (CCN) concentration were used to initiate a 1-D microphysical aerosol-cloud parcel model (ACPM). UAVs were equipped for a specific science mission, with an optical particle counter for aerosol distribution profiles, a cloud sensor to measure cloud extinction or a five-hole probe for 3-D wind vectors. UAV cloud measurements are rare and have only become possible in recent years through the miniaturization of instrumentation. These are the first UAV measurements at Mace Head. ACPM simulations are compared to in situ cloud extinction measurements from UAVs to quantify closure in terms of cloud shortwave radiative flux. Two out of seven cases exhibit sub-adiabatic vertical temperature profiles within the cloud, which suggests that entrainment processes affect cloud microphysical properties and lead to an overestimate of simulated cloud shortwave radiative flux. Including an entrainment parameterization and explicitly calculating the entrainment fraction in the ACPM simulations both improved cloud-top radiative closure. Entrainment reduced the difference between simulated and observation-derived cloud-top shortwave radiative flux (δRF) by between 25 and 60 W m-2. After accounting for entrainment

  7. Test of Mie-based single-scattering properties of non-spherical dust aerosols in radiative flux calculations

    International Nuclear Information System (INIS)

    Fu, Q.; Thorsen, T.J.; Su, J.; Ge, J.M.; Huang, J.P.

    2009-01-01

    We simulate the single-scattering properties (SSPs) of dust aerosols with both spheroidal and spherical shapes at a wavelength of 0.55 μm for two refractive indices and four effective radii. Herein spheres are defined by preserving both projected area and volume of a non-spherical particle. It is shown that the relative errors of the spheres to approximate the spheroids are less than 1% in the extinction efficiency and single-scattering albedo, and less than 2% in the asymmetry factor. It is found that the scattering phase function of spheres agrees with spheroids better than the Henyey-Greenstein (HG) function for the scattering angle range of 0-90 o . In the range of ∼90-180 o , the HG function is systematically smaller than the spheroidal scattering phase function while the spherical scattering phase function is smaller from ∼90 o to 145 o but larger from ∼145 o to 180 o . We examine the errors in reflectivity and absorptivity due to the use of SSPs of equivalent spheres and HG functions for dust aerosols. The reference calculation is based on the delta-DISORT-256-stream scheme using the SSPs of the spheroids. It is found that the errors are mainly caused by the use of the HG function instead of the SSPs for spheres. By examining the errors associated with the delta-four- and delta-two-stream schemes using various approximate SSPs of dust aerosols, we find that the errors related to the HG function dominate in the delta-four-stream results, while the errors related to the radiative transfer scheme dominate in the delta-two-stream calculations. We show that the relative errors in the global reflectivity due to the use of sphere SSPs are always less than 5%. We conclude that Mie-based SSPs of non-spherical dust aerosols are well suited in radiative flux calculations.

  8. High-Density and Very-Low-Density Lipoprotein Have Opposing Roles in Regulating Tumor-Initiating Cells and Sensitivity to Radiation in Inflammatory Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, Adam R. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Atkinson, Rachel L. [Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Reddy, Jay P. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Debeb, Bisrat G.; Larson, Richard; Li, Li [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Masuda, Hiroko; Brewer, Takae [Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Atkinson, Bradley J. [Department of Clinical Pharmacy Services, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Brewster, Abeena [Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Ueno, Naoto T. [Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Woodward, Wendy A., E-mail: wwoodward@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2015-04-01

    Purpose: We previously demonstrated that cholesterol-lowering agents regulate radiation sensitivity of inflammatory breast cancer (IBC) cell lines in vitro and are associated with less radiation resistance among IBC patients who undergo postmastectomy radiation. We hypothesized that decreasing IBC cellular cholesterol induced by treatment with lipoproteins would increase radiation sensitivity. Here, we examined the impact of specific transporters of cholesterol (ie lipoproteins) on the responses of IBC cells to self-renewal and to radiation in vitro and on clinical outcomes in IBC patients. Methods and Materials: Two patient-derived IBC cell lines, SUM 149 and KPL4, were incubated with low-density lipoproteins (LDL), very-low-density lipoproteins (VLDL), or high-density lipoproteins (HDL) for 24 hours prior to irradiation (0-6 Gy) and mammosphere formation assay. Cholesterol panels were examined in a cohort of patients with primary IBC diagnosed between 1995 and 2011 at MD Anderson Cancer Center. Lipoprotein levels were then correlated to patient outcome, using the log rank statistical model, and examined in multivariate analysis using Cox regression. Results: VLDL increased and HDL decreased mammosphere formation compared to untreated SUM 149 and KPL4 cells. Survival curves showed enhancement of survival in both of the IBC cell lines when pretreated with VLDL and, conversely, radiation sensitization in all cell lines when pretreated with HDL. In IBC patients, higher VLDL values (>30 mg/dL) predicted a lower 5-year overall survival rate than normal values (hazard ratio [HR] = 1.9 [95% confidence interval [CI]: 1.05-3.45], P=.035). Lower-than-normal patient HDL values (<60 mg/dL) predicted a lower 5-year overall survival rate than values higher than 60 mg/dL (HR = 3.21 [95% CI: 1.25-8.27], P=.015). Conclusions: This study discovered a relationship among the plasma levels of lipoproteins, overall patient response, and radiation resistance in IBC patients

  9. High-Density and Very-Low-Density Lipoprotein Have Opposing Roles in Regulating Tumor-Initiating Cells and Sensitivity to Radiation in Inflammatory Breast Cancer

    International Nuclear Information System (INIS)

    Wolfe, Adam R.; Atkinson, Rachel L.; Reddy, Jay P.; Debeb, Bisrat G.; Larson, Richard; Li, Li; Masuda, Hiroko; Brewer, Takae; Atkinson, Bradley J.; Brewster, Abeena; Ueno, Naoto T.; Woodward, Wendy A.

    2015-01-01

    Purpose: We previously demonstrated that cholesterol-lowering agents regulate radiation sensitivity of inflammatory breast cancer (IBC) cell lines in vitro and are associated with less radiation resistance among IBC patients who undergo postmastectomy radiation. We hypothesized that decreasing IBC cellular cholesterol induced by treatment with lipoproteins would increase radiation sensitivity. Here, we examined the impact of specific transporters of cholesterol (ie lipoproteins) on the responses of IBC cells to self-renewal and to radiation in vitro and on clinical outcomes in IBC patients. Methods and Materials: Two patient-derived IBC cell lines, SUM 149 and KPL4, were incubated with low-density lipoproteins (LDL), very-low-density lipoproteins (VLDL), or high-density lipoproteins (HDL) for 24 hours prior to irradiation (0-6 Gy) and mammosphere formation assay. Cholesterol panels were examined in a cohort of patients with primary IBC diagnosed between 1995 and 2011 at MD Anderson Cancer Center. Lipoprotein levels were then correlated to patient outcome, using the log rank statistical model, and examined in multivariate analysis using Cox regression. Results: VLDL increased and HDL decreased mammosphere formation compared to untreated SUM 149 and KPL4 cells. Survival curves showed enhancement of survival in both of the IBC cell lines when pretreated with VLDL and, conversely, radiation sensitization in all cell lines when pretreated with HDL. In IBC patients, higher VLDL values (>30 mg/dL) predicted a lower 5-year overall survival rate than normal values (hazard ratio [HR] = 1.9 [95% confidence interval [CI]: 1.05-3.45], P=.035). Lower-than-normal patient HDL values (<60 mg/dL) predicted a lower 5-year overall survival rate than values higher than 60 mg/dL (HR = 3.21 [95% CI: 1.25-8.27], P=.015). Conclusions: This study discovered a relationship among the plasma levels of lipoproteins, overall patient response, and radiation resistance in IBC patients

  10. Degradation behavior of linear low density polyethylene by ultraviolet radiation exposition for agricultural applications

    Energy Technology Data Exchange (ETDEWEB)

    Poveda, Patricia N.S.; Silva, Leonardo G.A., E-mail: lgasilva@ipen.br, E-mail: patricianegrini@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Ciro, Rosemeire, E-mail: rosemeireciro@msn.com [Faculdades Oswaldo Cruz (FOC), Sao Paulo, SP (Brazil); Viana, Hamilton M., E-mail: hmviana@gmail.com [Centro Universitario Fundacao de Santo Andre (FSA/FAENG), Santo Andre, SP (Brazil)

    2013-07-01

    Polyethylene is the most important polymer used in agricultural applications. Polymers are susceptible to changes in their chemical structures that affect their mechanical properties under weather condition. In Polyethylene, photo-oxidation can occur because of impurities or chromophore groups (catalytic residue, mineral fillers, some commercial additives as stabilizers, lubricants, plasticizers, etc.). The critical ageing factors for greenhouse built with LDPE film are: total solar radiation, air temperature, relative humidity, mechanical stress, agrochemicals, air pollution, and combinations of these factors. Exposure of plastics to UV radiation causes a loss in their mechanical properties and/or change in appearance, including reduced ductility, color changes, yellowing and cracking. Additives are added to plastics to enhance the durability of the final product. Today, there are several additive systems (light stabilizers) developed to work according to resin, final application, type of cultivation, and other characteristics. The main types of light stabilizers are: UV absorbers, quenchers and free radicals scavengers. In addition to the conventional organic additives, some inorganic additives were obtained recently with the development of nanotechnology. This study evaluates the different additive systems (HALS, NPCC, nZnO and nTiO{sub 2}), applied 0.25% (in weight) in LLDPE. The samples were mixed by high rotation homogenizer and extrusion. Later, the samples were molded by injection and aged in QUV-B simulating 6 months of exposure to weather. Tests of FT-IR and tensile strength comparing to the non-aged samples were carried out in order to evaluate the performance of several additive systems concerning the degradation behavior of linear low density polyethylene. (author)

  11. Degradation behavior of linear low density polyethylene by ultraviolet radiation exposition for agricultural applications

    International Nuclear Information System (INIS)

    Poveda, Patricia N.S.; Silva, Leonardo G.A.; Ciro, Rosemeire; Viana, Hamilton M.

    2013-01-01

    Polyethylene is the most important polymer used in agricultural applications. Polymers are susceptible to changes in their chemical structures that affect their mechanical properties under weather condition. In Polyethylene, photo-oxidation can occur because of impurities or chromophore groups (catalytic residue, mineral fillers, some commercial additives as stabilizers, lubricants, plasticizers, etc.). The critical ageing factors for greenhouse built with LDPE film are: total solar radiation, air temperature, relative humidity, mechanical stress, agrochemicals, air pollution, and combinations of these factors. Exposure of plastics to UV radiation causes a loss in their mechanical properties and/or change in appearance, including reduced ductility, color changes, yellowing and cracking. Additives are added to plastics to enhance the durability of the final product. Today, there are several additive systems (light stabilizers) developed to work according to resin, final application, type of cultivation, and other characteristics. The main types of light stabilizers are: UV absorbers, quenchers and free radicals scavengers. In addition to the conventional organic additives, some inorganic additives were obtained recently with the development of nanotechnology. This study evaluates the different additive systems (HALS, NPCC, nZnO and nTiO 2 ), applied 0.25% (in weight) in LLDPE. The samples were mixed by high rotation homogenizer and extrusion. Later, the samples were molded by injection and aged in QUV-B simulating 6 months of exposure to weather. Tests of FT-IR and tensile strength comparing to the non-aged samples were carried out in order to evaluate the performance of several additive systems concerning the degradation behavior of linear low density polyethylene. (author)

  12. Constraining the cosmic radiation density due to lepton number with Big Bang Nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Mangano, Gianpiero; Miele, Gennaro; Pisanti, Ofelia; Sarikas, Srdjan [Istituto Nazionale di Fisica Nucleare – Sezione di Napoli, Complesso Universitario di Monte S. Angelo, I-80126 Napoli (Italy); Pastor, Sergio, E-mail: mangano@na.infn.it, E-mail: miele@na.infn.it, E-mail: pastor@ific.uv.es, E-mail: pisanti@na.infn.it, E-mail: sarikas@na.infn.it [Instituto de Física Corpuscular (CSIC-Universitat de València), Ed. Institutos de Investigación, Apdo. correos 22085, E-46071 Valencia (Spain)

    2011-03-01

    The cosmic energy density in the form of radiation before and during Big Bang Nucleosynthesis (BBN) is typically parameterized in terms of the effective number of neutrinos N{sub eff}. This quantity, in case of no extra degrees of freedom, depends upon the chemical potential and the temperature characterizing the three active neutrino distributions, as well as by their possible non-thermal features. In the present analysis we determine the upper bounds that BBN places on N{sub eff} from primordial neutrino-antineutrino asymmetries, with a careful treatment of the dynamics of neutrino oscillations. We consider quite a wide range for the total lepton number in the neutrino sector, η{sub ν} = η{sub ν{sub e}}+η{sub ν{sub μ}}+η{sub ν{sub τ}} and the initial electron neutrino asymmetry η{sub ν{sub e}{sup in}}, solving the corresponding kinetic equations which rule the dynamics of neutrino (antineutrino) distributions in phase space due to collisions, pair processes and flavor oscillations. New bounds on both the total lepton number in the neutrino sector and the ν{sub e}−ν-bar {sub e} asymmetry at the onset of BBN are obtained fully exploiting the time evolution of neutrino distributions, as well as the most recent determinations of primordial {sup 2}H/H density ratio and {sup 4}He mass fraction. Note that taking the baryon fraction as measured by WMAP, the {sup 2}H/H abundance plays a relevant role in constraining the allowed regions in the η{sub ν}−η{sub ν{sub e}{sup in}} plane. These bounds fix the maximum contribution of neutrinos with primordial asymmetries to N{sub eff} as a function of the mixing parameter θ{sub 13}, and point out the upper bound N{sub eff}∼<3.4. Comparing these results with the forthcoming measurement of N{sub eff} by the Planck satellite will likely provide insight on the nature of the radiation content of the universe.

  13. A mathematical model for radiation hydrodynamics

    Directory of Open Access Journals (Sweden)

    Sebastiano Pennisi

    1990-11-01

    Full Text Available We adopt here the idea of describing a radiation field by means of the radiation energy density E and the radiative flux vector F which must satisfy a set of evolution equations; in these equations an unknown tensorial function P(E,F appears that is determined by the methods of extended thermodynamics.

  14. Material matters: Analysis of density uncertainty in 3D printing and its consequences for radiation oncology.

    Science.gov (United States)

    Craft, Daniel F; Kry, Stephen F; Balter, Peter; Salehpour, Mohammad; Woodward, Wendy; Howell, Rebecca M

    2018-04-01

    Using 3D printing to fabricate patient-specific devices such as tissue compensators, boluses, and phantoms is inexpensive and relatively simple. However, most 3D printing materials have not been well characterized, including their radiologic tissue equivalence. The purposes of this study were to (a) determine the variance in Hounsfield Units (HU) for printed objects, (b) determine if HU varies over time, and (c) calculate the clinical dose uncertainty caused by these material variations. For a sample of 10 printed blocks each of PLA, NinjaFlex, ABS, and Cheetah, the average HU and physical density were tracked at initial printing and over the course of 5 weeks, a typical timeframe for a standard course of radiotherapy. After initial printing, half the blocks were stored in open boxes, the other half in sealed bags with desiccant. Variances in HU and density over time were evaluated for the four materials. Various clinical photon and electron beams were used to evaluate potential errors in clinical depth dose as a function of assumptions made during treatment planning. The clinical depth error was defined as the distance between the correctly calculated 90% isodose line and the 90% isodose line calculated using clinically reasonable, but simplified, assumptions. The average HU measurements of individual blocks of PLA, ABS, NinjaFlex, and Cheetah varied by as much as 121, 30, 178, and 30 HU, respectively. The HU variation over 5 weeks was much smaller for all materials. The magnitude of clinical depth errors depended strongly on the material, energy, and assumptions, but some were as large as 9.0 mm. If proper quality assurance steps are taken, 3D printed objects can be used accurately and effectively in radiation therapy. It is critically important, however, that the properties of any material being used in patient care be well understood and accounted for. © 2018 American Association of Physicists in Medicine.

  15. Comparison between nano-diamond and carbon nanotube doping effects on critical current density and flux pinning in MgB2

    International Nuclear Information System (INIS)

    Cheng, C H; Yang, Y; Munroe, P; Zhao, Y

    2007-01-01

    Doping effects of nano-diamond and carbon nanotubes (CNTs) on critical current density of bulk MgB 2 have been studied. CNTs are found prone to be doped into the MgB 2 lattice whereas nano-diamond tends to form second-phase inclusions in the MgB 2 matrix, leading to a more significant improvement of J c (H) by doping by nano-diamond than by CNTs in MgB 2 . TEM reveals tightly packed MgB 2 nanograins (50-100 nm) with a dense distribution of diamond nanoparticles (10-20 nm) inside MgB 2 grains in nano-diamond-doped samples. Such a unique microstructure leads to a flux pinning behaviour different from that in CNTs-doped MgB 2

  16. Applications of Robust, Radiation Hard AlGaN Optoelectronic Devices in Space Exploration and High Energy Density Physics

    Energy Technology Data Exchange (ETDEWEB)

    Sun, K.

    2011-05-04

    This slide show presents: space exploration applications; high energy density physics applications; UV LED and photodiode radiation hardness; UV LED and photodiode space qualification; UV LED AC charge management; and UV LED satellite payload instruments. A UV LED satellite will be launched 2nd half 2012.

  17. Alpha slow-moving high-density-lipoprotein subfraction in serum of a patient with radiation enteritis and peritoneal carcinosis

    International Nuclear Information System (INIS)

    Peynet, J.; Legrand, A.; Messing, B.; Thuillier, F.; Rousselet, F.

    1989-01-01

    An alpha slow-moving high-density-lipoprotein (HDL) subfraction was seen in a patient presenting with radiation enteritis and peritoneal carcinosis, who was given long-term cyclic parenteral nutrition. This subfraction, observed in addition to normal HDL, was precipitated with low-density lipoproteins (LDL) and very-low-density lipoproteins (VLDL) by sodium phosphotungstate-magnesium chloride. The patient's serum lipoproteins were analyzed after fractionation by density gradient ultracentrifugation. The alpha slow-moving HDL floated in the ultracentrifugation subfractions with densities ranging from 1.028 to 1.084 kg/L, and their main apolipoproteins included apolipoprotein E in addition to apolipoprotein A-I. These HDL were larger than HDL2. The pathogenesis of this unusual HDL subfraction is hypothesized

  18. Study on the radiation flux and temperature distributions of the concentrator-receiver system in a solar dish/Stirling power facility

    International Nuclear Information System (INIS)

    Li Zhigang; Tang Dawei; Du Jinglong; Li Tie

    2011-01-01

    Uniform heater temperature and high optical-thermal efficiency are crucial for the reliable and economical operation of a Solar Dish/Stirling engine facility. The Monte-Carlo ray-tracing method is utilized to predict the radiation flux distributions of the concentrator-receiver system. The ray-tracing method is first validated by experiment, then the radiation flux profiles on the solar receiver surface for faceted real concentrator and ideal paraboloidal concentrator, irradiated by Xe-arc lamps and real sun, for different aperture positions and receiver shapes are analyzed, respectively. The resulted radiation flux profiles are subsequently transferred to a CFD code as boundary conditions to numerically simulate the fluid flow and conjugate heat transfer in the receiver cavity by coupling the radiation, natural convection and heat conduction together, and the CFD method is also validated through experiment. The results indicate that a faceted concentrator in combination with a solar simulator composed of 12 Xe-arc lamps is advantageous to drive the solar Stirling engine for all-weather indoor tests. Based on the simulation results, a solar receiver-Stirling heater configuration is designed to achieve a considerably uniform temperature distribution on the heater head tubes while maintaining a high efficiency of 60.7%. - Highlights: → Radiation flux in Dish/Stirling system is analyzed by validated ray-tracing method. → Temperature field on the solar receiver is analyzed by a validated CFD method. → Effects of Xe-arc lamp solar simulator and faceted real concentrator are analyzed. → Effects of different receiver positions and receiver shapes are investigated. → A Stirling heater configuration is presented with uniform temperature field.

  19. Estimating shortwave solar radiation using net radiation and meteorological measurements

    Science.gov (United States)

    Shortwave radiation has a wide variety of uses in land-atmosphere interactions research. Actual evapotranspiration estimation that involves stomatal conductance models like Jarvis and Ball-Berry require shortwave radiation to estimate photon flux density. However, in most weather stations, shortwave...

  20. Radiative decay engineering: the role of photonic mode density in biotechnology

    International Nuclear Information System (INIS)

    Lakowicz, Joseph R; Malicka, Joanna; Gryczynski, Ignacy; Gryczynski, Zygmunt; Geddes, Chris D

    2003-01-01

    Fluorescence detection is a central technology in biological research and biotechnology. A vast array of fluorescent probes are available with diverse spectral properties. These properties were 'engineered' into fluorophores by modification of the chemical structures. Essentially, all present uses of fluorescence rely on the radiation of energy into optically transparent media, the free space which surrounds the fluorophores. In this paper, we summarize an opportunity for novel fluorescence technology based on modification of the photonic mode density around the fluorophore and thus control of its spectral properties. This modification can be accomplished by proximity of fluorophores to metallic particles of gold, silver and possibly others. By engineering the size and shape of the metal particles, and the location of the fluorophores relative to the surfaces, fluorophores can be quenched, display increases in quantum yield, and changes in lifetime. Fluorophore-metal surface combinations can even display directional rather than isotropic emission. We describe recent experimental results and suggest potential biomedical applications of fluorophore-metal particle interactions. (topical review)

  1. Radiation technique in density and strength testing of coniferous structural timber

    International Nuclear Information System (INIS)

    Dzbenski, W.; Krzosek, S.

    1998-01-01

    The control process of intermediate and final wood products manufacturing is more and more frequently assisted by flow detectors. In radiation devices cesium isotope 137 Cs is replaced by less harmful americium 241 Am. Americium 241 Am was used in the measuring device made in The Academy of Mining and Metallurgy in Cracow. The device was applied in Warsaw Agricultural University (SGGW) in research on Polish structural timber. Negative influence of anatomical defects (knots, compression wood, resinasis, slope of grain, decay) was estimated by gammascopy method. Botanical species (pine, spruce), position in a stem (sapwood, heartwood), anatomical direction (radial, tangential) and moisture content were taken into account. The method of determination a critical place in timber were density is the lowest value (what is an obligatory criterion of stress graded structural timber according to EN standards) was developed. The practical implementation of the method can be reached when sawmills producing structural timber (especially for export) will be more interested in using miniaturized isotope densitometers. (author)

  2. The collapse of a molecular cloud core to stellar densities using radiation non-ideal magnetohydrodynamics

    Science.gov (United States)

    Wurster, James; Bate, Matthew R.; Price, Daniel J.

    2018-04-01

    We present results from radiation non-ideal magnetohydrodynamics (MHD) calculations that follow the collapse of rotating, magnetized, molecular cloud cores to stellar densities. These are the first such calculations to include all three non-ideal effects: ambipolar diffusion, Ohmic resistivity, and the Hall effect. We employ an ionization model in which cosmic ray ionization dominates at low temperatures and thermal ionization takes over at high temperatures. We explore the effects of varying the cosmic ray ionization rate from ζcr = 10-10 to 10-16 s-1. Models with ionization rates ≳10-12 s-1 produce results that are indistinguishable from ideal MHD. Decreasing the cosmic ray ionization rate extends the lifetime of the first hydrostatic core up to a factor of 2, but the lifetimes are still substantially shorter than those obtained without magnetic fields. Outflows from the first hydrostatic core phase are launched in all models, but the outflows become broader and slower as the ionization rate is reduced. The outflow morphology following stellar core formation is complex and strongly dependent on the cosmic ray ionization rate. Calculations with high ionization rates quickly produce a fast (≈14 km s-1) bipolar outflow that is distinct from the first core outflow, but with the lowest ionization rate, a slower (≈3-4 km s-1) conical outflow develops gradually and seamlessly merges into the first core outflow.

  3. Study of electron densities of normal and neoplastic human breast tissues by Compton scattering using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Antoniassi, M.; Conceicao, A.L.C. [Departamento de Fisica-Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto-Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil); Poletti, M.E., E-mail: poletti@ffclrp.usp.br [Departamento de Fisica-Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto-Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil)

    2012-07-15

    Electron densities of 33 samples of normal (adipose and fibroglangular) and neoplastic (benign and malignant) human breast tissues were determined through Compton scattering data using a monochromatic synchrotron radiation source and an energy dispersive detector. The area of Compton peaks was used to determine the electron densities of the samples. Adipose tissue exhibits the lowest values of electron density whereas malignant tissue the highest. The relationship with their histology was discussed. Comparison with previous results showed differences smaller than 4%. - Highlights: Black-Right-Pointing-Pointer Electron density of normal and neoplastic breast tissues was measured using Compton scattering. Black-Right-Pointing-Pointer Monochromatic synchrotron radiation was used to obtain the Compton scattering data. Black-Right-Pointing-Pointer The area of Compton peaks was used to determine the electron densities of samples. Black-Right-Pointing-Pointer Adipose tissue shows the lowest electron density values whereas the malignant tissue the highest. Black-Right-Pointing-Pointer Comparison with previous results showed differences smaller than 4%.

  4. The radiation and variable viscosity effects on electrically conducting fluid over a vertically moving plate subjected to suction and heat flux

    Energy Technology Data Exchange (ETDEWEB)

    Malekzadeh, P., E-mail: malekzadeh@pgu.ac.i [Department of Mechanical Engineering, Persian Gulf University, Bushehr 75168 (Iran, Islamic Republic of); Center of Excellence for Computational Mechanics, Shiraz University, Shiraz (Iran, Islamic Republic of); Moghimi, M.A. [Department of Mechanical Engineering, School of Engineering, Shaid Bahonar University, Kerman (Iran, Islamic Republic of); Nickaeen, M. [K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of)

    2011-05-15

    Research highlights: {yields} A new application of the differential quadrature method in thermo-fluid fields. {yields} Moving vertical plate with suction and heat flux is considered. {yields} Fluid with variable viscosity subjected to thermal radiation is studied. -- Abstract: In this paper, firstly, the applicability of the differential quadrature method (DQM) as an efficient and accurate numerical method for solving the problem of variable viscosity and thermally radiative unsteady magneto-hydrodynamic (MHD) flow over a moving vertical plate with suction and heat flux is investigated. The spatial as well as the temporal domains are discretized using the DQM. The fast rate of convergence of the method is demonstrated and for the cases that a solution is available, comparison is done. Then, effects of the temperature dependence of viscosity and different fluid parameters on the velocity and temperature of transient MHD flow subjected to the above mentioned boundary condition are studied.

  5. Pediatric radiation dose and risk from bone density measurements using a GE Lunar Prodigy scanner.

    Science.gov (United States)

    Damilakis, J; Solomou, G; Manios, G E; Karantanas, A

    2013-07-01

    Effective radiation doses associated with bone mineral density examinations performed on children using a GE Lunar Prodigy fan-beam dual-energy X-ray absorptiometry (DXA) scanner were found to be comparable to doses from pencil-beam DXA devices, i.e., lower than 1 μSv. Cancer risks associated with acquisitions obtained in this study are negligible. No data were found in the literature on radiation doses and potential risks following pediatric DXA performed on GE Lunar DXA scanners. This study aimed to estimate effective doses and associated cancer risks involved in pediatric examinations performed on a GE Lunar Prodigy scanner. Four physical anthropomorphic phantoms representing newborn, 1-, 5-, and 10-year-old patients were employed to simulate DXA exposures. All acquisitions were carried out using the Prodigy scanner. Dose measurements were performed for spine and dual femur using the phantoms simulating the 5- and 10-year-old child. Moreover, doses associated with whole-body examinations were measured for the four phantoms used in the current study. The gender-average effective dose for spine and hip examinations were 0.65 and 0.36 μSv, respectively, for the phantom representing the 5-year-old child and 0.93 and 0.205 μSv, respectively, for the phantom representing the 10-year-old child. Effective doses for whole-body examinations were 0.25, 0.22, 0.19, and 0.15 μSv for the neonate, 1-, 5-, and 10-year old child, respectively. The estimated lifetime cancer risks were negligible, i.e., 0.02-0.25 per million, depending on the sex, age, and type of DXA examination. A formula is presented for the estimation of effective dose from examinations performed on GE Lunar Prodigy scanners installed in other institutions. The effective doses and potential cancer risks associated with pediatric DXA examinations performed on a GE Lunar Prodigy fan-beam scanner were found to be comparable to doses and risks reported from pencil-beam DXA devices.

  6. Effect of combustion characteristics on wall radiative heat flux in a 100 MWe oxy-coal combustion plant

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.; Ryu, C. [Sungkyunkwan Univ., Suwon (Korea, Republic of). School of Mechanical Engineering; Chae, T.Y. [Sungkyunkwan Univ., Suwon (Korea, Republic of). School of Mechanical Engineering; Korea Institute of Industrial Technology, Cheonan (Korea, Republic of). Energy System R and D Group; Yang, W. [Korea Institute of Industrial Technology, Cheonan (Korea, Republic of). Energy System R and D Group; Kim, Y.; Lee, S.; Seo, S. [Korea Electric Power Research Institute (KEPRI), Daejeon (Korea, Republic of). Power Generation Lab.

    2013-07-01

    Oxy-coal combustion exhibits different reaction, flow and heat transfer characteristics from air-coal combustion due to different properties of oxidizer and flue gas composition. This study investigated the wall radiative heat flux (WRHF) of air- and oxy-coal combustion in a simple hexahedral furnace and in a 100 MWe single-wall-fired boiler using computational modeling. The hexahedral furnace had similar operation conditions with the boiler, but the coal combustion was ignored by prescribing the gas properties after complete combustion at the inlet. The concentrations of O{sub 2} in the oxidizers ranging between 26 and 30% and different flue gas recirculation (FGR) methods were considered in the furnace. In the hexahedral furnace, the oxy-coal case with 28% of O{sub 2} and wet FGR had a similar value of T{sub af} with the air-coal combustion case, but its WRHF was 12% higher. The mixed FGR case with about 27% O{sub 2} in the oxidizer exhibited the WRHF similar to the air-coal case. During the actual combustion in the 100 MWe boiler using mixed FGR, the reduced volumetric flow rates in the oxy-coal cases lowered the swirl strength of the burners. This stretched the flames and moved the high temperature region farther to the downstream. Due to this reason, the case with 30% O{sub 2} in the oxidizers achieved a WRHF close to that of air-coal combustion, although its adiabatic flame temperature (T{sub af}) and WHRF predicted in the simplified hexahedral furnace was 103 K and 10% higher, respectively. Therefore, the combustion characteristics and temperature distribution significantly influences the WRHF, which should be assessed to determine the ideal operating conditions of oxy- coal combustion. The choice of the weighted sum of gray gases model (WSGGM) was not critical in the large coal-fired boiler.

  7. Highly biocompatible, nanocrystalline hydroxyapatite synthesized in a solvothermal process driven by high energy density microwave radiation

    Science.gov (United States)

    Smolen, Dariusz; Chudoba, Tadeusz; Malka, Iwona; Kedzierska, Aleksandra; Lojkowski, Witold; Swieszkowski, Wojciech; Kurzydlowski, Krzysztof Jan; Kolodziejczyk-Mierzynska, Małgorzata; Lewandowska-Szumiel, Małgorzata

    2013-01-01

    A microwave, solvothermal synthesis of highly biocompatible hydroxyapatite (HAp) nanopowder was developed. The process was conducted in a microwave radiation field having a high energy density of 5 W/mL and over a time less than 2 minutes. The sample measurements included: powder X-ray diffraction, density, specific surface area, and chemical composition. The morphology and structure were investigated by scanning electron microscopy as well as transmission electron microscopy (TEM). The thermal behavior analysis was conducted using a simultaneous thermal analysis technique coupled with quadruple mass spectrometry. Additionally, Fourier transform infrared spectroscopy tests of heated samples were performed. A degradation test and a biocompatibility study in vitro using human osteoblast cells were also conducted. The developed method enables the synthesis of pure, fully crystalline hexagonal HAp nanopowder with a specific surface area close to 240 m2/g and a Ca/P molar ratio equal to 1.57. TEM measurements showed that this method results in particles with an average grain size below 6 nm. A 28-day degradation test conducted according to the ISO standard indicated a 22% loss of initial weight and a calcium ion concentration at 200 μmol/dm3 in the tris(hydroxymethyl)aminomethane hydrochloride test solution. The cytocompatibility of the obtained material was confirmed in a culture of human bone derived cells, both in an indirect test using the material extract, and in direct contact. A quantitative analysis was based on the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide. Viability assay as well as on DNA content measurements in the PicoGreen test. Indirect observations were performed at one point in time according to the ISO standard for in vitro cytotoxicity (ie, after 24 hours of cell exposure to the extracts). The direct contact tests were completed at three time points: after 24 hours, on day 7, and on day 14 of a culture in an osteogenic

  8. Top-down and Bottom-up aerosol-cloud-closure: towards understanding sources of unvertainty in deriving cloud radiative flux

    Science.gov (United States)

    Sanchez, K.; Roberts, G.; Calmer, R.; Nicoll, K.; Hashimshoni, E.; Rosenfeld, D.; Ovadnevaite, J.; Preissler, J.; Ceburnis, D.; O'Dowd, C. D. D.; Russell, L. M.

    2017-12-01

    Top-down and bottom-up aerosol-cloud shortwave radiative flux closures were conducted at the Mace Head atmospheric research station in Galway, Ireland in August 2015. Instrument platforms include ground-based, unmanned aerial vehicles (UAV), and satellite measurements of aerosols, clouds and meteorological variables. The ground-based and airborne measurements of aerosol size distributions and cloud condensation nuclei (CCN) concentration were used to initiate a 1D microphysical aerosol-cloud parcel model (ACPM). UAVs were equipped for a specific science mission, with an optical particle counter for aerosol distribution profiles, a cloud sensor to measure cloud extinction, or a 5-hole probe for 3D wind vectors. These are the first UAV measurements at Mace Head. ACPM simulations are compared to in-situ cloud extinction measurements from UAVs to quantify closure in terms of cloud shortwave radiative flux. Two out of seven cases exhibit sub-adiabatic vertical temperature profiles within the cloud, which suggests that entrainment processes affect cloud microphysical properties and lead to an overestimate of simulated cloud shortwave radiative flux. Including an entrainment parameterization and explicitly calculating the entrainment fraction in the ACPM simulations both improved cloud-top radiative closure. Entrainment reduced the difference between simulated and observation-derived cloud-top shortwave radiative flux (δRF) by between 25 W m-2 and 60 W m-2. After accounting for entrainment, satellite-derived cloud droplet number concentrations (CDNC) were within 30% of simulated CDNC. In cases with a well-mixed boundary layer, δRF is no greater than 20 W m-2 after accounting for cloud-top entrainment, and up to 50 W m-2 when entrainment is not taken into account. In cases with a decoupled boundary layer, cloud microphysical properties are inconsistent with ground-based aerosol measurements, as expected, and δRF is as high as 88 W m-2, even high (> 30 W m-2) after

  9. Test of E1-radiative strength function and level density models by 155 Gd (n,2γ) 156 Gd reaction

    International Nuclear Information System (INIS)

    Voinov, A.V.

    1996-01-01

    The information about the level density of 156 Gd nucleus and strength functions of γ transitions extracted from two γ-cascade spectra of the 155 Gd (n,2γ) 156 Gd reaction is analyzed. The method of statistical simulation of γ-cascade intensity is applied for calculation of the main parameters of experimental spectra. The method is used to extract the information on the E1-radiative strength function of γ transitions and level density in the 156 Gd nucleus. It is shown that at an excitation energy above 3 MeV the level density of 156 Gd nucleus must decrease in comparison with that calculated within the Fermi gas model. Its is concluded that possible explanation of the observed effect is connected with the influence of pairing correlations on the level density in nuclei

  10. The relationship between sol fraction and radiation dose in radiation crosslinking of low-density polyethylene (LDPE)/ethylenevinylacetate copolymer (EVA) blend

    International Nuclear Information System (INIS)

    Zhang, W.X.; Liu, Y.T.; Sun, J.Z.

    1990-01-01

    In this paper, two different methods were used to prepare the blend of low-density polyethylene (LDPE) and ethylene vinyl acetate copolymer (EVA). One of them was mechanical blending, and the other was solution blending. The relationship between sol fraction and radiation dose of different weight ratio polymer blends has been studied. The method to calculate the β b value of polymer blend system (LDPE/EVA) has been established. (author)

  11. Average Nuclear Level Densities and Radiative Strength Functions in 56,57FE from Primary (Gamma)-Ray Spectra

    International Nuclear Information System (INIS)

    Tavukcu, E.; Becker, J.A.; Bernstein, L.A.; Garrett, P.E.; Guttormsen, M.; Mitchell, G.E.; Rekstad, J.; Schiller, A.; Siem, S.; Voinov, A.; Younes, W.

    2002-01-01

    An experimental primary γ-ray spectrum vs. excitation-energy bin (P(E x , E γ ) matrix) in a light-ion reaction is obtained for 56,57 Fe isotopes using a subtraction method. By factorizing the P(E x , E γ ) matrix according to the Axel-Brink hypothesis the nuclear level density and the radiative strength function (RSF) in 56,57 Fe are extracted simultaneously. A step structure is observed in the level density for both isotopes, and is interpreted as the breaking of Cooper pairs. The RSFs for 56,57 Fe reveal an anomalous enhancement at low γ-ray energies

  12. Improved Statistical Model Of 10.7-cm Solar Radiation

    Science.gov (United States)

    Vedder, John D.; Tabor, Jill L.

    1993-01-01

    Improved mathematical model simulates short-term fluctuations of flux of 10.7-cm-wavelength solar radiation during 91-day averaging period. Called "F10.7 flux", important as measure of solar activity and because it is highly correlated with ultraviolet radiation causing fluctuations in heating and density of upper atmosphere. F10.7 flux easily measureable at surface of Earth.

  13. Parametrization of the average ionization and radiative cooling rates of carbon plasmas in a wide range of density and temperature

    International Nuclear Information System (INIS)

    Gil, J.M.; Rodriguez, R.; Florido, R.; Rubiano, J.G.; Mendoza, M.A.; Nuez, A. de la; Espinosa, G.; Martel, P.; Minguez, E.

    2013-01-01

    In this work we present an analysis of the influence of the thermodynamic regime on the monochromatic emissivity, the radiative power loss and the radiative cooling rate for optically thin carbon plasmas over a wide range of electron temperature and density assuming steady state situations. Furthermore, we propose analytical expressions depending on the electron density and temperature for the average ionization and cooling rate based on polynomial fittings which are valid for the whole range of plasma conditions considered in this work. -- Highlights: ► We compute the average ionization, cooling rates and emissivities of carbon plasmas. ► We compare LTE and NLTE calculations of these magnitudes. ► We perform a parametrization of these magnitudes in a wide range of plasma conditions. ► We provide information about where LTE regime assumption is accurate

  14. Estimation of the soil heat flux/net radiation ratio based on spectral vegetation indexes in high-latitude Arctic areas

    International Nuclear Information System (INIS)

    Jacobsen, A.; Hansen, B.U.

    1999-01-01

    The vegetation communities in the Arctic environment are very sensitive to even minor climatic variations and therefore the estimation of surface energy fluxes from high-latitude vegetated areas is an important subject to be pursued. This study was carried out in July-August and used micro meteorological data, spectral reflectance signatures, and vegetation biomass to establish the relation between the soil heat flux/net radiation (G / Rn) ratio and spectral vegetation indices (SVIs). Continuous measurements of soil temperature and soil heat flux were used to calculate the surface ground heat flux by use of conventional methods, and the relation to surface temperature was investigated. Twenty-seven locations were established, and six samples per location, including the measurement of the surface temperature and net radiation to establish the G/Rn ratio and simultaneous spectral reflectance signatures and wet biomass estimates, were registered. To obtain regional reliability, the locations were chosen in order to represent the different Arctic vegetation communities in the study area; ranging from dry tundra vegetation communities (fell fields and dry dwarf scrubs) to moist/wet tundra vegetation communities (snowbeds, grasslands and fens). Spectral vegetation indices, including the simple ratio vegetation index (RVI) and the normalized difference vegetation index (NDVI), were calculated. A comparison of SVIs to biomass proved that RVI gave the best linear expression, and NDVI the best exponential expression. A comparison of SVIs and the surface energy flux ratio G / Rn proved that NDVI gave the best linear expression. SPOT HRV images from July 1989 and 1992 were used to map NDVI and G / Rn at a regional scale. (author)

  15. Automatic atlas based electron density and structure contouring for MRI-based prostate radiation therapy on the cloud

    International Nuclear Information System (INIS)

    Dowling, J A; Burdett, N; Chandra, S; Rivest-Hénault, D; Ghose, S; Salvado, O; Fripp, J; Greer, P B; Sun, J; Parker, J; Pichler, P; Stanwell, P

    2014-01-01

    Our group have been developing methods for MRI-alone prostate cancer radiation therapy treatment planning. To assist with clinical validation of the workflow we are investigating a cloud platform solution for research purposes. Benefits of cloud computing can include increased scalability, performance and extensibility while reducing total cost of ownership. In this paper we demonstrate the generation of DICOM-RT directories containing an automatic average atlas based electron density image and fast pelvic organ contouring from whole pelvis MR scans.

  16. Automatic Atlas Based Electron Density and Structure Contouring for MRI-based Prostate Radiation Therapy on the Cloud

    Science.gov (United States)

    Dowling, J. A.; Burdett, N.; Greer, P. B.; Sun, J.; Parker, J.; Pichler, P.; Stanwell, P.; Chandra, S.; Rivest-Hénault, D.; Ghose, S.; Salvado, O.; Fripp, J.

    2014-03-01

    Our group have been developing methods for MRI-alone prostate cancer radiation therapy treatment planning. To assist with clinical validation of the workflow we are investigating a cloud platform solution for research purposes. Benefits of cloud computing can include increased scalability, performance and extensibility while reducing total cost of ownership. In this paper we demonstrate the generation of DICOM-RT directories containing an automatic average atlas based electron density image and fast pelvic organ contouring from whole pelvis MR scans.

  17. Divertor heat flux mitigation in the National Spherical Torus Experimenta)

    Science.gov (United States)

    Soukhanovskii, V. A.; Maingi, R.; Gates, D. A.; Menard, J. E.; Paul, S. F.; Raman, R.; Roquemore, A. L.; Bell, M. G.; Bell, R. E.; Boedo, J. A.; Bush, C. E.; Kaita, R.; Kugel, H. W.; Leblanc, B. P.; Mueller, D.; NSTX Team

    2009-02-01

    Steady-state handling of divertor heat flux is a critical issue for both ITER and spherical torus-based devices with compact high power density divertors. Significant reduction of heat flux to the divertor plate has been achieved simultaneously with favorable core and pedestal confinement and stability properties in a highly shaped lower single null configuration in the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 2000] using high magnetic flux expansion at the divertor strike point and the radiative divertor technique. A partial detachment of the outer strike point was achieved with divertor deuterium injection leading to peak flux reduction from 4-6MWm-2to0.5-2MWm-2 in small-ELM 0.8-1.0MA, 4-6MW neutral beam injection-heated H-mode discharges. A self-consistent picture of the outer strike point partial detachment was evident from divertor heat flux profiles and recombination, particle flux and neutral pressure measurements. Analytic scrape-off layer parallel transport models were used for interpretation of NSTX detachment experiments. The modeling showed that the observed peak heat flux reduction and detachment are possible with high radiated power and momentum loss fractions, achievable with divertor gas injection, and nearly impossible to achieve with main electron density, divertor neutral density or recombination increases alone.

  18. Radiation-Induced Grafting with One-Step Process of Waste Polyurethane onto High-Density Polyethylene

    Directory of Open Access Journals (Sweden)

    Jong-Seok Park

    2015-12-01

    Full Text Available The recycling of waste polyurethane (PU using radiation-induced grafting was investigated. The grafting of waste PU onto a high-density polyethylene (HDPE matrix was carried out using a radiation technique with maleic anhydride (MAH. HDPE pellets and PU powders were immersed in a MAH-acetone solution. Finally, the prepared mixtures were irradiated with an electron beam accelerator. The grafted composites were characterized by Fourier transformed infrared spectroscopy (FT-IR, surface morphology, and mechanical properties. To make a good composite, the improvement in compatibility between HDPE and PU is an important factor. Radiation-induced grafting increased interfacial adhesion between the PU domain and the HDPE matrix. When the absorbed dose was 75 kGy, the surface morphology of the irradiated PU/HDPE composite was nearly a smooth and single phase, and the elongation at break increased by approximately three times compared with that of non-irradiated PU/HDPE composite.

  19. Effect of ultraviolet radiation in the photo-oxidation of High Density Polyethylene and Biodegradable Polyethylene films

    International Nuclear Information System (INIS)

    Martínez-Romo, A; Mota, R González; Bernal, J J Soto; Candelas, I Rosales; Reyes, C Frausto

    2015-01-01

    One of the most widely used plastics in the world is the High density polyethylene (HDPE), it is a stable material due to its carbon-carbon bonds, causing their slow degradation; which is why we are looking for alternative ways to accelerate the degradation process of this polymer. An alternative is the addition of oxidized groups in its molecular structure, which results in the development of polymers susceptible to biodegradation (PE-BIO). In this paper, HDPE and PE-BIO films were exposed to UV-B radiation (320-280 nm) at different exposure times, 0-60 days. The effects of UV radiation in samples of HDPE and PE-BIO were characterized using infrared spectroscopy with attenuated total reflectance (ATR). The results show that the exposed materials undergo changes in their molecular structure, due to the infrared bands formed which corresponds to the photo-oxidation of HDPE and PE films when submitted to UV-B radiation

  20. Stacking fault density as engineering criterion for resistance to radiation swelling of alloys' FCC- and BCC-lattice

    International Nuclear Information System (INIS)

    Zheltov, Yu.V.; Ageev, V.S.; Kolesnikov, Yu.G.

    1990-01-01

    The experimental data on influence of Mn, Cr, Ni, P, B, Ce alloying in austenitic and simultaneously Nb, V, B alloying in ferritic steels and also heat treatment on stacking fault density (SFD) are represented. In all cases besides influence of Cr in austenitic steel the increase of SFD is shown. The decrease of radiation swelling of industrial steels at the increase of their SFD, measured by X-rays, was studied. The tendency of increase of relative radiation swelling change at SFD increase at relative fluence rise is verified. It is shown that SFD may be a perspective proximate characteristics of choice of radiation-resistant steel melts within one steel quality. 14 refs.; 4 figs. (author)

  1. Highly biocompatible, nanocrystalline hydroxyapatite synthesized in a solvothermal process driven by high energy density microwave radiation

    Directory of Open Access Journals (Sweden)

    Smolen D

    2013-02-01

    Full Text Available Dariusz Smolen1, Tadeusz Chudoba1, Iwona Malka1, Aleksandra Kedzierska1, Witold Lojkowski1, Wojciech Swieszkowski2, Krzysztof Jan Kurzydlowski2, Malgorzata Kolodziejczyk-Mierzynska3, Malgorzata Lewandowska-Szumiel31Polish Academy of Science, Institute of High Pressure Physics, Warsaw, Poland; 2Faculty of Materials Engineering, Warsaw University of Technology, Warsaw, Poland; 3Department of Histology and Embryology, Center of Biostructure Research, Medical University of Warsaw, Warsaw, PolandAbstract: A microwave, solvothermal synthesis of highly biocompatible hydroxyapatite (HAp nanopowder was developed. The process was conducted in a microwave radiation field having a high energy density of 5 W/mL and over a time less than 2 minutes. The sample measurements included: powder X-ray diffraction, density, specific surface area, and chemical composition. The morphology and structure were investigated by scanning electron microscopy as well as transmission electron microscopy (TEM. The thermal behavior analysis was conducted using a simultaneous thermal analysis technique coupled with quadruple mass spectrometry. Additionally, Fourier transform infrared spectroscopy tests of heated samples were performed. A degradation test and a biocompatibility study in vitro using human osteoblast cells were also conducted. The developed method enables the synthesis of pure, fully crystalline hexagonal HAp nanopowder with a specific surface area close to 240 m2/g and a Ca/P molar ratio equal to 1.57. TEM measurements showed that this method results in particles with an average grain size below 6 nm. A 28-day degradation test conducted according to the ISO standard indicated a 22% loss of initial weight and a calcium ion concentration at 200 µmol/dm3 in the tris(hydroxymethylaminomethane hydrochloride test solution. The cytocompatibility of the obtained material was confirmed in a culture of human bone derived cells, both in an indirect test using the material

  2. Roles of coercivity and remanent flux density of permanent magnet in interior permanent magnet synchronous motor (IPMSM) performance for electric vehicle applications

    Science.gov (United States)

    Won, Hoyun; Hong, Yang-Ki; Lee, Woncheol; Choi, Minyeong

    2018-05-01

    We used four rotor topologies of an interior permanent magnet synchronous motor (IPMSM) to investigate the effects of remanent flux density (Br) and coercivity (Hc) of permanent magnet on motor performance. Commercial strontium hexaferrite (SrFe12O19: energy product, (BH)max, of 4.62 MGOe) and Nd-Fe-B ((BH)max of 38.2 MGOe) magnets were used for the rotor designs. The same machine specifications and magnet volume keep constant, while the Hc and Br vary to calculate torque and energy efficiency with the finite-element analysis. A combination of high Hc and low Br more effectively increased maximum torque of IPMSM when the hexaferrite magnet was used. For Nd-Fe-B magnet, the same combination did not affect maximum torque, but increased energy efficiency at high speed. Therefore, the Hc value of a permanent magnet is more effective than the Br in producing high maximum torque for SrM-magnet based IPMSM and high energy efficiency at high speed for Nd-Fe-B magnet based IPMSM.

  3. Generating an AC amplitude magnetic flux density value up to 150 μT at a frequency up to 100 kHz

    Science.gov (United States)

    Ulvr, Michal; Polonský, Jakub

    2017-05-01

    AC magnetic field analyzers with a triaxial coil probe are widely used by health and safety professionals, in manufacturing, and in service industries. For traceable calibration of these analyzers, it is important to be able to generate a stable, homogeneous reference AC magnetic flux density (MFD). In this paper, the generating of AC amplitude MFD value of 150 μT by single-layer Helmholtz type solenoid, described in previous work, was expanded up to a frequency of 100 kHz using the effect of serial resonance. A programmable capacitor array has been developed with a range of adjustable values from 50 pF to 51225 pF. In addition, the multi-layer search coil with a nominal area turns value of 1.3m2, used for adjusting AC MFD in the solenoid, has been modified by a transimpedance amplifier for use in a wider frequency range than up to 3 kHz. The possibility of using the programmable capacitor array up to 150 kHz has also been tested. An AC amplitude MFD value of 150 μT can be generated with expanded uncertainty better than 0.6% up to 100 kHz.

  4. Superconductivity, critical current density, and flux pinning in MgB2-x(SiC)x/2 superconductor after SiC nanoparticle doping

    Science.gov (United States)

    Dou, S. X.; Pan, A. V.; Zhou, S.; Ionescu, M.; Wang, X. L.; Horvat, J.; Liu, H. K.; Munroe, P. R.

    2003-08-01

    We investigated the effect of SiC nanoparticle doping on the crystal lattice structure, critical temperature Tc, critical current density Jc, and flux pinning in MgB2 superconductor. A series of MgB2-x(SiC)x/2 samples with x=0-1.0 were fabricated using an in situ reaction process. The contraction of the lattice and depression of Tc with increasing SiC doping level remained rather small most likely due to the counterbalancing effect of Si and C co-doping. The high level Si and C co-doping allowed the creation of intragrain defects and highly dispersed nanoinclusions within the grains which can act as effective pinning centers for vortices, improving Jc behavior as a function of the applied magnetic field. The enhanced pinning is mainly attributable to the substitution-induced defects and local structure fluctuations within grains. A pinning mechanism is proposed to account for different contributions of different defects in MgB2-x(SiC)x/2 superconductors.

  5. Secretory IgA, albumin level, and bone density as markers of biostimulatory effects of laser radiation

    Science.gov (United States)

    Kucerova, Hana; Dostalova, Tatjana; Himmlova, Lucia; Bartova, Jirina; Mazanek, Jiri

    1998-12-01

    The aim of contribution is to evaluate the effects of low- level laser radiation on healing process after human molars extraction in lower jaw using frequency 5 Hz, 292 Hz and 9000 Hz. Changes in bone density and monitoring of secretory IgA and albumin levels in saliva were used as a marker of biostimulatory effect. Bone density after extraction and 6 month after surgical treatment was examined using the dental digital radiography. Bone healing was followed by osseointegration of bone structure in extraction wound. Changes of bone density, secretory IgA and albumin levels were compared in groups of patients with laser therapy and control group without laser therapy. Differences in levels of the saliva markers (sIgA and albumin) were found to be significant comparing irradiated and non-irradiated groups, as well as comparing groups irradiated by various modulatory frequencies. Density of alveolar bone (histogram) was examined on five slices acquired from every RVG image. Histograms were evaluated with computer program for microscopic image analysis. Differences of density were verified in area of the whole slice. There were no significant differences found between the bone density in irradiated and non irradiated groups perhaps due to our used therapeutical diagram.

  6. Application of gamma radiation backscattering in determining density and Zsub(eff) of scattering material Monte Carlo optimization of configuration

    International Nuclear Information System (INIS)

    Cechak, T.

    1982-01-01

    Applying Gardner's method of double evaluation one detector should be positioned such that its response should be independent of the material density and the second detector should be positioned so as to maximize changes in response due to density changes. The experimental scanning for optimal energy is extremely time demanding. A program was written based on the Monte Carlo method which solves the problem of error magnitude in case the computation of gamma radiation backscattering neglects multiply scattered photons, the problem of how this error depends on the atomic number of the scattering material as well as the problem of whether the representation of individual scatterings in the spectrum of backscattered photons depends on the positioning of the detector. 42 detectors, 8 types of material and 10 different density values were considered. The computed dependences are given graphically. (M.D.)

  7. Top-down and bottom-up aerosol–cloud closure: towards understanding sources of uncertainty in deriving cloud shortwave radiative flux

    Directory of Open Access Journals (Sweden)

    K. J. Sanchez

    2017-08-01

    Full Text Available Top-down and bottom-up aerosol–cloud shortwave radiative flux closures were conducted at the Mace Head Atmospheric Research Station in Galway, Ireland, in August 2015. This study is part of the BACCHUS (Impact of Biogenic versus Anthropogenic emissions on Clouds and Climate: towards a Holistic UnderStanding European collaborative project, with the goal of understanding key processes affecting aerosol–cloud shortwave radiative flux closures to improve future climate predictions and develop sustainable policies for Europe. Instrument platforms include ground-based unmanned aerial vehicles (UAVs1 and satellite measurements of aerosols, clouds and meteorological variables. The ground-based and airborne measurements of aerosol size distributions and cloud condensation nuclei (CCN concentration were used to initiate a 1-D microphysical aerosol–cloud parcel model (ACPM. UAVs were equipped for a specific science mission, with an optical particle counter for aerosol distribution profiles, a cloud sensor to measure cloud extinction or a five-hole probe for 3-D wind vectors. UAV cloud measurements are rare and have only become possible in recent years through the miniaturization of instrumentation. These are the first UAV measurements at Mace Head. ACPM simulations are compared to in situ cloud extinction measurements from UAVs to quantify closure in terms of cloud shortwave radiative flux. Two out of seven cases exhibit sub-adiabatic vertical temperature profiles within the cloud, which suggests that entrainment processes affect cloud microphysical properties and lead to an overestimate of simulated cloud shortwave radiative flux. Including an entrainment parameterization and explicitly calculating the entrainment fraction in the ACPM simulations both improved cloud-top radiative closure. Entrainment reduced the difference between simulated and observation-derived cloud-top shortwave radiative flux (δRF by between 25 and 60 W m−2. After

  8. Reproducible automated breast density measure with no ionizing radiation using fat-water decomposition MRI.

    Science.gov (United States)

    Ding, Jie; Stopeck, Alison T; Gao, Yi; Marron, Marilyn T; Wertheim, Betsy C; Altbach, Maria I; Galons, Jean-Philippe; Roe, Denise J; Wang, Fang; Maskarinec, Gertraud; Thomson, Cynthia A; Thompson, Patricia A; Huang, Chuan

    2018-04-06

    Increased breast density is a significant independent risk factor for breast cancer, and recent studies show that this risk is modifiable. Hence, breast density measures sensitive to small changes are desired. Utilizing fat-water decomposition MRI, we propose an automated, reproducible breast density measurement, which is nonionizing and directly comparable to mammographic density (MD). Retrospective study. The study included two sample sets of breast cancer patients enrolled in a clinical trial, for concordance analysis with MD (40 patients) and reproducibility analysis (10 patients). The majority of MRI scans (59 scans) were performed with a 1.5T GE Signa scanner using radial IDEAL-GRASE sequence, while the remaining (seven scans) were performed with a 3T Siemens Skyra using 3D Cartesian 6-echo GRE sequence with a similar fat-water separation technique. After automated breast segmentation, breast density was calculated using FraGW, a new measure developed to reliably reflect the amount of fibroglandular tissue and total water content in the entire breast. Based on its concordance with MD, FraGW was calibrated to MR-based breast density (MRD) to be comparable to MD. A previous breast density measurement, Fra80-the ratio of breast voxels with density changes and treatment response. 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018. © 2018 International Society for Magnetic Resonance in Medicine.

  9. Effects of soil water decline on diurnal and seasonal variations in sap flux density for differently aged Japanese cypress (Chamaecyparis obtusa trees

    Directory of Open Access Journals (Sweden)

    Kenji Tsuruta

    2014-01-01

    Full Text Available The effects of soil drought on transpiration are often neglected when predicting transpiration for forests in humid regions under the influence of the Asian monsoon. These effects have indeed been neglected for Japanese cypress, Chamaecyparis obtusa, a major plantation species in Japan and the surrounding area, probably because previous studies have reported no clear effects of soil drought on transpiration for Japanese cypress forests. However, a few studies have reported an apparent reduction in transpiration with soil drought for young Japanese cypress forests. It remains unclear whether such a reduction in transpiration is limited to young Japanese cypress forests or if it is not uncommon for mature Japanese cypress forests, which occupy a large area in Japan. To clarify this point, we conducted sap flux measurements in a year with soil drought on three differently aged Japanese cypress stands including mature (43 years old and relatively young (23 and 26 years old trees. In a diurnal time scale, a cross correlation analysis of sap flux density (Fd and vapor pressure deficit (VPD showed that the time lags between Fd and VPD were 1-3 h in dry soil conditions. These were larger than those of wet soil conditions (<1 h for all sample trees. Fd at a given VPD in dry soil conditions was smaller than that in wet soil conditions for all sample trees; a 28%–63% reduction in the rate of change in Fd was observed under dry soil conditions. Because our results were obtained when the non-exceedance probability of recorded monthly precipitation was 9%–18%, the results suggest the need to consider the effects of soil drought more extensively. Those effects should be considered for not only relatively young but also mature Japanese cypress when predicting diurnal and seasonal patterns of transpiration in years with soil drought, and when predicting inter-annual patterns of transpiration for Japanese cypress despite humid

  10. Fundamental radiation effects in αAg-Zn alloys: Zener relaxation, study of the mobility of point defects and the evolution of their populations in a particle flux

    International Nuclear Information System (INIS)

    Halbwachs, Michel.

    1977-01-01

    After a recall on the physical effects of radiations, a model used to describe the defect populations produced in a fast particle flux is presented. The experimental devices used and the measurements carried out on a solid solution of αAg-Zn are described. The results obtained in an electron flux are compared with the forecastings of the theoretical models. The mobility and the apparent recombination radius of vacancies and autointerstitials, the absorption efficiency of dislocations in regard to point defects and the participation of autointerstitials to short-range order are studied. A similar study carried out under neutron irradiation is reported. The influence of neutron doses and temperature on atomic mobility is investigated. An experiment carried out under gamma photon irradiation enables a comparison to be made between the creation of defects by gamma photons and electrons [fr

  11. MHD effects and heat transfer for the UCM fluid along with Joule heating and thermal radiation using Cattaneo-Christov heat flux model

    Energy Technology Data Exchange (ETDEWEB)

    Shah, S., E-mail: sajidshah313@yahoo.com; Hussain, S.; Sagheer, M. [Department of Mathematics, Capital University of Science and Technology, Islamabad (Pakistan)

    2016-08-15

    Present study examines the numerical analysis of MHD flow of Maxwell fluid with thermal radiation and Joule heating by considering the recently developed Cattaneo-Christov heat flux model which explains the time relaxation characteristics for the heat flux. The objective is to analyze the governing parameters such as viscoelastic fluid parameter, Magnetic parameter, Eckert and Prandtl number’s impact on the velocity and temperature profiles through graphs and tables. Suitable similarity transformations have been used to reduce the formulated PDEs into a system of coupled non-linear ODEs. Shooting technique has been invoked for finding the numerical solutions of the dimensionless velocity and temperature profiles. Additionally, the MATLAB built-in routine bvp4c has also been used to verify and strengthen the results obtained by shooting method. From some special cases of the present work, a comparison with the previously published results has been presented.

  12. Benchmarking CCMI models' top-of-atmosphere flux in the 9.6-µm ozone band using AURA TES Instantaneous Radiative Kernel

    Science.gov (United States)

    Kuai, L.; Bowman, K. W.; Worden, H. M.; Paulot, F.; Paynter, D.; Oman, L.; Strode, S. A.; Rozanov, E.; Stenke, A.; Revell, L. E.; Plummer, D. A.

    2017-12-01

    The estimated ozone radiative forcing (RF) from chemical-climate models range widely from +0.2 to +0.6 Wm-2. The reason has never been well understood. Since the ozone absorption in the 9.6 μm band contributes 97% of the O3 longwave RF, the variation of outgoing longwave radiation (OLR) due to ozone is dominant by this band. The observed TOA flux over 9.6 µm ozone band by Thermal Emission Spectrometer (TES) shows the global distribution has unique spatial patterns. In addition, the simulated TOA fluxes over 9.6 µm ozone band by different models have never been evaluated against observations. The bias of TOA flux from model could be primarily contributed by the bias of temperature, water vapor and ozone. Furthermore, the sensitivity of TOA flux to tropospheric ozone (instantaneous radiative kernel, IRK) may also affected by these biases (Kuai et al., 2017). The bias in TOA flux would eventually propagate into model calculations of ozone RF and cause divergence of the predictions of future climate by models. In this study, we applied the observation-based IRK product by AURA TES to attribute the CCMI model bias in TOA flux over 9.6 µm ozone band to ozone, water vapor, air temperature, and surface temperature. The comparisons of the three CCMI models (AM3, SOCOL3 and GEOCCM) to TES observations suggest that 1) all models underestimate the TOA flux at tropics and subtropics. 2) The TOA flux bias is comparable similar by AM3 and GEOSCC (-0.2 to -0.3 W/m2) however is larger for the relative young model, SOCOL3 (-0.4 to -0.6 W/m2). 3) The contributions by surface temperature are similarly moderate (-0.2 W/m2). 4) The contribution of ozone is largest by SOCOL3 (-0.3 W/m2), smallest by GEOSCCM (less than 0.1 W/m2) and moderate by AM3 (-0.2 W/m2). 5) Overall, the contributions by atmospheric temperature are all small (less than 0.1 W/m2). 6) The contribution of water vapor is negative and small by both SOCOL3 and GEOSCCM (0.1 W/m2) however large and positive by AM3 (0

  13. Particle flux and temperature dependence of carbon impurity production from an inertially-cooled limiter in tore supra

    International Nuclear Information System (INIS)

    DeMichelis, C.; Monier-Garbet, P.; Guilhem, D.

    1998-01-01

    A visible endoscope system and an infrared camera system have been used to study the flux of carbon from an inertially-cooled graphite limiter in Tore Supra. From the variation in the carbon flux with plasma parameters new data have been obtained describing the dependence of radiation enhanced sublimation (RES) and chemical sputtering on incident ion flux. Other characteristics of RES under plasma operation conditions have also been studied. The dependence of RES on incident deuterium particle flux density is found to be in reasonable agreement with the expected particle flux scaling over a range of particle fluxes varying by a factor ∼ 25, extending the present scaling to higher flux density values. Chemical sputtering has been observed, but only in regions of the limiter with low incident deuterium fluxes. Values inferred for the chemical sputtering yield are similar to those measured with a temperature controlled test limiter in Textor. (author)

  14. Mechanical properties of polyamide 6,6/low density polyethylene blend by ionizing radiation

    International Nuclear Information System (INIS)

    Pino, Eddy S.; Feitosa, Marcos A.F.

    2007-01-01

    Polymer blending is a growing scientific and commercial development activity. In most of the cases, polymeric blends are formed by thermodynamically immiscible components. Such blends require the use of compatibilizers that, often, are copolymers, graft copolymers or any mean that improves the dispersion and adhesion of the blend phases. Compatibility of a polymer blend plays an important role in determining the blend properties for its end use. In this work, the improvement of mechanical properties of PA 6,6/LDPE 75/25% wt/wt composition blend, using electron radiation, was studied. Samples for mechanical test were melt-mixed in an extruder and then injection-molded. These samples were electron irradiated to overall doses of 50, 100, 150, 200 and 250 kGy. Tensile measurements have shown that the strength at break increases with an increase of radiation dose. Hardness Shore D measurements show that this property also increases as a function of radiation dose. On the other hand, Impact Izod tests show that the resistance to impact decreases with the increase of radiation dose. The behavior of these bulk and surface properties implies that ionizing radiation produces changes in the mechanical performance of the irradiated blend due to a combined radiation inducing effects, cross-linking and the compatibility of blend components. (author)

  15. Comparison of collisional radiative models for edge electron density reconstruction from Li I (2s-2p) emission profiles

    Energy Technology Data Exchange (ETDEWEB)

    Stoschus, H.; Hudson, B.; Munoz Burgos, J. M. [Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831-0117 (United States); Thomas, D. M. [General Atomics, San Diego, California 92186-5608 (United States); Schweinzer, J. [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, 85748 Garching (Germany)

    2012-10-15

    Four collisional radiative models (CRMs) for reconstruction of the edge electron density profile from the measured Li I (2s-2p) emission profile of an accelerated lithium beam are compared using experimental data from DIII-D. It is shown for both L- and H-mode plasmas that edge density profiles reconstructed with the CRMs DDD2, ABSOLUT, [Sasaki et al. Rev. Sci. Instrum. 64, 1699 (1993)] and a new model developed at DIII-D agree in a density scan from n{sub e}{sup ped}= (2.0-6.5) Multiplication-Sign 10{sup 19} m{sup -3} within 20%, 20%, <5%, and 40%, respectively, of the pedestal density measured with Thomson scattering. Profile shape and absolute density vary in a scan of the effective ion charge Z{sub eff}= 1-6 up to a factor of two but agree with Thomson data for Z{sub eff}= 1-2 within the error bars.

  16. Experimental Evolution of UV-C Radiation Tolerance: Emergence of Adaptive and Non-Adaptive Traits in Escherichia coli Under Differing Flux Regimes

    Science.gov (United States)

    Moffet, A.; Okansinski, A.; Sloan, C.; Grace, J. M.; Paulino-Lima, I. G.; Gentry, D.; Rothschild, L. J.; Camps, M.

    2014-12-01

    High-energy ultraviolet (UV-C) radiation is a significant challenge to life in environments such as high altitude areas, the early Earth, the Martian surface, and space. As UV-C exposure is both a selection pressure and a mutagen, adaptation dynamics in such environments include a high rate of change in both tolerance-related and non-tolerance-related genes, as well changes in linkages between the resulting traits. Determining the relationship between the intensity and duration of the UV-C exposure, mutation rate, and emergence of UV-C resistance will inform our understanding of both the emergence of radiation-related extremophily in natural environments and the optimal strategies for generating artificial extremophiles. In this study, we iteratively exposed an Escherichia colistrain to UV-C radiation of two different fluxes, 3.3 J/m^2/s for 6 seconds and 0.5 J/m^2/s for 40 seconds, with the same overall fluence of 20 J/m^2. After each iteration, cells from each exposure regime were assayed for increased UV-C tolerance as an adaptive trait. The exposed cells carried a plasmid bearing a TEM beta-lactamase gene, which in the absence of antibiotic treatment is a neutral reporter for mutagenesis. Sequencing of this gene allowed us to determine the baseline mutation frequency for each flux. As an additional readout for adaptation, the presence of extended-spectrum beta-lactamase mutations was tested by plating UV-exposed cultures in cefotaxime plates. We observed an increase of approximately one-million-fold in UV-C tolerance over seven iterations; no significant difference between the two fluxes was found. Future work will focus on identifying the genomic changes responsible for the change in UV-C tolerance; determining the mechanisms of the emerged UV-C tolerance; and performing competition experiments between the iteration strains to quantify fitness tradeoffs resulting from UV-C adaptation.

  17. Scattering of lower-hybrid waves by drift-wave density fluctuations: solutions of the radiative transfer equation

    International Nuclear Information System (INIS)

    Andrews, P.L.; Perkins, F.W.

    1983-01-01

    The investigation of the scattering of lower-hybrid waves by density fluctuations arising from drift waves in tokamaks is distinguished by the presence in the wave equation of a large, random, derivative-coupling term. The propagation of the lower-hybrid waves is well represented by a radiative transfer equation when the scale size of the density fluctuations is small compared to the overall plasma size. The radiative transfer equation is solved in two limits: first, the forward scattering limit, where the scale size of density fluctuations is large compared to the lower-hybrid perpendicular wavelength, and second, the large-angle scattering limit, where this inequality is reversed. The most important features of these solutions are well represented by analytical formulas derived by simple arguments. Based on conventional estimates for density fluctuations arising from drift waves and a parabolic density profile, the optical depth tau for scattering through a significant angle, is given by tauroughly-equal(2/N 2 /sub parallel/) (#betta#/sub p/i0/#betta#) 2 (m/sub e/c 2 /2T/sub i/)/sup 1/2/ [c/α(Ω/sub i/Ω/sub e/)/sup 1/2/ ], where #betta#/sub p/i0 is the central ion plasma frequency and T/sub i/ denotes the ion temperature near the edge of the plasma. Most of the scattering occurs near the surface. The transmission through the scattering region scales as tau - 1 and the emerging intensity has an angular spectrum proportional to cos theta, where sin theta = k/sub perpendicular/xB/sub p//(k/sub perpendicular/B/sub p/), and B/sub p/ is the poloidal field

  18. On the use of radiative surface temperature to estimate sensible heat flux over sparse shrubs in Nevada

    Science.gov (United States)

    Chehbouni, A.; Nichols, W. D.; Qi, J.; Njoku, E. G.; Kerr, Y. H.; Cabot, F.

    1994-01-01

    The accurate partitioning of available energy into sensible and latent heat flux is crucial to the understanding of surface atmosphere interactions. This issue is more complicated in arid and semi arid regions where the relative contribution to surface fluxes from the soil and vegetation may vary significantly throughout the day and throughout the season. A three component model to estimate sensible heat flux over heterogeneous surfaces is presented. The surface was represented with two adjacent compartments. The first compartment is made up of two components, shrubs and shaded soil, the second of open 'illuminated' soil. Data collected at two different sites in Nevada (U.S.) during the Summers of 1991 and 1992 were used to evaluate model performance. The results show that the present model is sufficiently general to yield satisfactory results for both sites.

  19. Growth and Accumulation of Secondary Metabolites in Perilla as Affected by Photosynthetic Photon Flux Density and Electrical Conductivity of the Nutrient Solution

    Directory of Open Access Journals (Sweden)

    Na Lu

    2017-05-01

    Full Text Available The global demand for medicinal plants is increasing. The quality of plants grown outdoors, however, is difficult to control. Myriad environmental factors influence plant growth and directly impact biosynthetic pathways, thus affecting the secondary metabolism of bioactive compounds. Plant factories use artificial lighting to increase the quality of medicinal plants and stabilize production. Photosynthetic photon flux density (PPFD and electrical conductivity (EC of nutrient solutions are two important factors that substantially influence perilla (Perilla frutescens, Labiatae plant growth and quality. To identify suitable levels of PPFD and EC for perilla plants grown in a plant factory, the growth, photosynthesis, and accumulation of secondary metabolites in red and green perilla plants were measured at PPFD values of 100, 200, and 300 μmol m-2 s-1 in nutrient solutions with EC values of 1.0, 2.0, and 3.0 dS m-1. The results showed significant interactive effects between PPFD and EC for both the fresh and dry weights of green perilla, but not for red perilla. The fresh and dry weights of shoots and leafy areas were affected more by EC than by PPFD in green perilla, whereas they were affected more by PPFD than by EC in red perilla. Leaf net photosynthetic rates were increased as PPFD increased in both perilla varieties, regardless of EC. The perillaldehyde concentration (mg g-1 in red perilla was unaffected by the treatments, but accumulation in plants (mg per plant was significantly enhanced as the weight of dry leaves increased. Perillaldehyde concentrations in green perilla showed significant differences between combinations of the highest PPFD with the highest EC and the lowest PPFD with the lowest EC. Rosmarinic acid concentration (mg g-1 was increased in a combination of low EC and high PPFD conditions. Optimal cultivation conditions of red and green perilla in plant factory will be discussed in terms of plant growth and contents of

  20. Azimuthal and radial variations in sap flux density and effects on stand-scale transpiration estimates in a Japanese cedar forest.

    Science.gov (United States)

    Shinohara, Yoshinori; Tsuruta, Kenji; Ogura, Akira; Noto, Fumikazu; Komatsu, Hikaru; Otsuki, Kyoichi; Maruyama, Toshisuke

    2013-05-01

    Understanding radial and azimuthal variation, and tree-to-tree variation, in sap flux density (Fd) as sources of uncertainty is important for estimating transpiration using sap flow techniques. In a Japanese cedar (Cryptomeria japonica D. Don.) forest, Fd was measured at several depths and aspects for 18 trees, using heat dissipation (Granier-type) sensors. We observed considerable azimuthal variation in Fd. The coefficient of variation (CV) calculated from Fd at a depth of 0-20 mm (Fd1) and Fd at a depth of 20-40 mm (Fd2) ranged from 6.7 to 37.6% (mean = 28.3%) and from 19.6 to 62.5% (mean = 34.6%) for the -azimuthal directions. Fd at the north aspect averaged for nine trees, for which azimuthal measurements were made, was -obviously smaller than Fd at the other three aspects (i.e., west, south and east) averaged for the nine trees. Fd1 averaged for the nine trees was significantly larger than Fd2 averaged for the nine trees. The error for stand-scale transpiration (E) estimates caused by ignoring the azimuthal variation was larger than that caused by ignoring the radial variation. The error caused by ignoring tree-to-tree variation was larger than that caused by ignoring both radial and azimuthal variations. Thus, tree-to-tree variation in Fd would be more important than both radial and azimuthal variations in Fd for E estimation. However, Fd for each tree should not be measured at a consistent aspect but should be measured at various aspects to make accurate E estimates and to avoid a risk of error caused by the relationship of Fd to aspect.

  1. Radiation transport simulation of the Martian GCR surface flux and dose estimation using spherical geometry in PHITS compared to MSL-RAD measurements.

    Science.gov (United States)

    Flores-McLaughlin, John

    2017-08-01

    Planetary bodies and spacecraft are predominantly exposed to isotropic radiation environments that are subject to transport and interaction in various material compositions and geometries. Specifically, the Martian surface radiation environment is composed of galactic cosmic radiation, secondary particles produced by their interaction with the Martian atmosphere, albedo particles from the Martian regolith and occasional solar particle events. Despite this complex physical environment with potentially significant locational and geometric dependencies, computational resources often limit radiation environment calculations to a one-dimensional or slab geometry specification. To better account for Martian geometry, spherical volumes with respective Martian material densities are adopted in this model. This physical description is modeled with the PHITS radiation transport code and compared to a portion of measurements from the Radiation Assessment Detector of the Mars Science Laboratory. Particle spectra measured between 15 November 2015 and 15 January 2016 and PHITS model results calculated for this time period are compared. Results indicate good agreement between simulated dose rates, proton, neutron and gamma spectra. This work was originally presented at the 1st Mars Space Radiation Modeling Workshop held in 2016 in Boulder, CO. Copyright © 2017. Published by Elsevier Ltd.

  2. Aerosol-Induced Radiative Flux Changes Off the United States Mid-Atlantic Coast: Comparison of Values Calculated from Sunphotometer and In Situ Data with Those Measured by Airborne Pyranometer

    Science.gov (United States)

    Russell, P. B.; Livingston, J. M.; Hignett, P.; Kinne, S.; Wong, J.; Chien, A.; Bergstrom, R.; Durkee, P.; Hobbs, P. V.

    2000-01-01

    The Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) measured a variety of aerosol radiative effects (including flux changes) while simultaneously measuring the chemical, physical, and optical properties of the responsible aerosol particles. Here we use TARFOX-determined aerosol and surface properties to compute shortwave radiative flux changes for a variety of aerosol situations, with midvisible optical depths ranging from 0.06 to 0.55. We calculate flux changes by several techniques with varying degrees of sophistication, in part to investigate the sensitivity of results to computational approach. We then compare computed flux changes to those determined from aircraft measurements. Calculations using several approaches yield downward and upward flux changes that agree with measurements. The agreement demonstrates closure (i.e. consistency) among the TARFOX-derived aerosol properties, modeling techniques, and radiative flux measurements. Agreement between calculated and measured downward flux changes is best when the aerosols are modeled as moderately absorbing (midvisible single-scattering albedos between about 0.89 and 0.93), in accord with independent measurements of the TARPOX aerosol. The calculated values for instantaneous daytime upwelling flux changes are in the range +14 to +48 W/sq m for midvisible optical depths between 0.2 and 0.55. These values are about 30 to 100 times the global-average direct forcing expected for the global-average sulfate aerosol optical depth of 0.04. The reasons for the larger flux changes in TARFOX include the relatively large optical depths and the focus on cloud-free, daytime conditions over the dark ocean surface. These are the conditions that produce major aerosol radiative forcing events and contribute to any global-average climate effect.

  3. Atomically Smooth Epitaxial Ferroelectric Thin Films for the Development of a Nonvolatile, Ultrahigh Density, Fast, Low Voltage, Radiation-Hard Memory

    National Research Council Canada - National Science Library

    Ahn, Charles H

    2006-01-01

    The goal of this research is to fabricate atomically smooth, single crystalline, complex oxide thin film nanostructures for use in a nonvolatile, ultrahigh density, fast, low voltage, radiation-hard memory...

  4. Preparation of High Density Polyethylene/Waste Polyurethane Blends Compatibilized with Polyethylene-Graft-Maleic Anhydride by Radiation

    Directory of Open Access Journals (Sweden)

    Jong-Seok Park

    2015-04-01

    Full Text Available Polyurethane (PU is a very popular polymer that is used in a variety of applications due to its good mechanical, thermal, and chemical properties. However, PU recycling has received significant attention due to environmental issues. In this study, we developed a recycling method for waste PU that utilizes the radiation grafting technique. Grafting of waste PU was carried out using a radiation technique with polyethylene-graft-maleic anhydride (PE-g-MA. The PE-g-MA-grafted PU/high density polyethylene (HDPE composite was prepared by melt-blending at various concentrations (0–10 phr of PE-g-MA-grafted PU. The composites were characterized using fourier transform infrared spectroscopy (FT-IR, and their surface morphology and thermal/mechanical properties are reported. For 1 phr PU, the PU could be easily introduced to the HDPE during the melt processing in the blender after the radiation-induced grafting of PU with PE-g-MA. PE-g-MA was easily reacted with PU according to the increasing radiation dose and was located at the interface between the PU and the HDPE during the melt processing in the blender, which improved the interfacial interactions and the mechanical properties of the resultant composites. However, the elongation at break for a PU content >2 phr was drastically decreased.

  5. Sea Surface Micro-Structure: Relation to Air-Sea Fluxes, Bubble Transport and Electromagnetic Wave Radiation

    National Research Council Canada - National Science Library

    Cox, Charles

    2001-01-01

    .... The camera responds to radiation in the three to five micrometer wavelength range. This is a useful range because the intensity of black body radiation from the water surface in this range is highly sensitive to the temperature of the source...

  6. Variations of electron fluxes in the outer radiation belt near the boundary of a trapping region during substorms

    International Nuclear Information System (INIS)

    Ginzburg, E.A.; Malyshev, A.B.

    1979-01-01

    Variations of electron fluxes with the energy Esub(e) > 0.7 MeV have been investigated near the high-latitude boundary of electron trapping region in the night and day sections of the magnetosphere. It is found that during substorms the natural changes of the structure of electron fluxes take place. On the night side of the magnetosphere after the flux boundary drift to the equator at the preliminary phase, its sharp drift to the pole at the explosion phase takes place with further slow ( during 1-2 hours) shift to the initial position. The boundary position reconstruction period coincide by duration with the life time of negative bays at magnetograms of the night section stations. On the day side the boundary of electron fluxes recorded drifts to the pole in 30-60 min after the beginning of the substorm exposion phase. The results obtained are interpreted within the framework of the theory of adiabatic drift of trapped electrons and their pitch-angular diffusion under the effect of very low frequency waves

  7. Comparison of 37 months global net radiation flux derived from PICARD-BOS over the same period observations of CERES and ARGO

    Science.gov (United States)

    Zhu, Ping; Wild, Martin

    2016-04-01

    The absolute level of the global net radiation flux (NRF) is fixed at the level of [0.5-1.0] Wm-2 based on the ocean heat content measurements [1]. The space derived global NRF is at the same order of magnitude than the ocean [2]. Considering the atmosphere has a negligible effects on the global NRF determination, the surface global NRF is consistent with the values determined from space [3]. Instead of studying the absolute level of the global NRF, we focus on the interannual variation of global net radiation flux, which were derived from the PICARD-BOS experiment and its comparison with values over the same period but obtained from the NASA-CERES system and inferred from the ocean heat content survey by ARGO network. [1] Allan, Richard P., Chunlei Liu, Norman G. Loeb, Matthew D. Palmer, Malcolm Roberts, Doug Smith, and Pier-Luigi Vidale (2014), Changes in global net radiative imbalance 1985-2012, Geophysical Research Letters, 41 (no.15), 5588-5597. [2] Loeb, Norman G., John M. Lyman, Gregory C. Johnson, Richard P. Allan, David R. Doelling, Takmeng Wong, Brian J. Soden, and Graeme L. Stephens (2012), Observed changes in top-of-the-atmosphere radiation and upper-ocean heating consistent within uncertainty, Nature Geoscience, 5 (no.2), 110-113. [3] Wild, Martin, Doris Folini, Maria Z. Hakuba, Christoph Schar, Sonia I. Seneviratne, Seiji Kato, David Rutan, Christof Ammann, Eric F. Wood, and Gert Konig-Langlo (2015), the energy balance over land and oceans: an assessment based on direct observations and CMIP5 climate models, Climate Dynamics, 44 (no.11-12), 3393-3429.

  8. Flammability of radiation cross-linked low density polyethylene as an insulating material for wire and cable

    International Nuclear Information System (INIS)

    Basfar, A.A.

    2002-01-01

    Various formulations of low-density polyethylene blended with ethylene vinyl acetate were prepared to improve the flame retardancy for wire and cable applications. The prepared formulations were cross-linked by γ-rays to 50, 100, 150 and 200 kGy in the presence of trimethylolpropane triacrylate (TMPTA). The effect of thermal aging on mechanical properties of these formulations were investigated. In addition, the influence of various combinations of aluminum trihydroxide and zinc borate as flame retardant fillers on the flammability was explored. Limiting oxygen index (LOI) and average extent of burning were used to characterize the flammability of investigated formulations. An improved flame retardancy of low density polyethylene was achieved by various combinations of flame ratardant fillers and cross-linking by gamma radiation

  9. Cylindrical implosion to measure the radiative properties of high density and temperature plasmas

    International Nuclear Information System (INIS)

    Xu Yan; Rose, S.J.

    2000-01-01

    Cylindrical implosion is of great interest because of its excellent diagnostic access. The authors present one-dimensional numerical simulations to explore the plasma conditions that may be achieved. Combined with the numerical data, the development of Rayleigh-Taylor instabilities and Richtmyer-Meshkov instabilities in those targets are estimated. The authors found that it is possible to achieve a high density and temperature plasma with a relatively low temperature and density gradient using a cylindrical implosion directly-driven by a high-power laser

  10. Ducting of the Whistler-Mode Waves by Magnetic Field-Aligned Density Enhancements in the Radiation Belt

    Science.gov (United States)

    Streltsov, A. V.; Bengtson, M.; English, D.; Miller, M.; Turco, L.

    2017-12-01

    Whistler-mode waves (or whistlers) are the right-hand polarized electromagnetic waves with a frequency in the range above the lower hybrid frequency and below the electron cyclotron frequency. They can efficiently interact with energetic electrons in the equatorial magnetosphere and remediate them from the earth's radiation belt. These interactions are non-linear, they depend on the wave amplitude, and for them to be efficient the wave power needs to be delivered from the transmitter to the interaction region without significant losses. The main physical mechanism which can solve this problem is ducting/guiding of whistlers by magnetic field-aligned density inhomogeneities or ducts. We present results from a modeling of whistler-mode waves observed by the NASA Van Allen Probes satellites inside the ducts formed by density enhancements (also known as, high-density ducts or HDD). Our previous studies suggest that HDD can confine without leakage only waves with some particular parameters (frequency, perpendicular and parallel wavelength) connected with the parameters of the duct (like duct's "width" and "depth"). Our numerical results confirm that 1) the high-density ducts with amplitudes and perpendicular sizes observed by the RBSP satellites can indeed guide whistlers over significant distances along the ambient magnetic field with small leakage, and 2) the quality of the ducting indeed depends on the wave perpendicular and parallel wavelengths and, therefore, the fact that the wave is ducted by HDD can be used to determine parameters of the wave.

  11. Average profiles of the solar wind and outer radiation belt during the extreme flux enhancement of relativistic electrons at geosynchronous orbit

    Directory of Open Access Journals (Sweden)

    R. Kataoka

    2008-06-01

    Full Text Available We report average profiles of the solar wind and outer radiation belt during the extreme flux enhancement of relativistic electrons at geosynchronous orbit (GEO. It is found that seven of top ten extreme events at GEO during solar cycle 23 are associated with the magnetosphere inflation during the storm recovery phase as caused by the large-scale solar wind structure of very low dynamic pressure (<1.0 nPa during rapid speed decrease from very high (>650 km/s to typical (400–500 km/s in a few days. For the seven events, the solar wind parameters, geomagnetic activity indices, and relativistic electron flux and geomagnetic field at GEO are superposed at the local noon period of GOES satellites to investigate the physical cause. The average profiles support the "double inflation" mechanism that the rarefaction of the solar wind and subsequent magnetosphere inflation are one of the best conditions to produce the extreme flux enhancement at GEO because of the excellent magnetic confinement of relativistic electrons by reducing the drift loss of trapped electrons at dayside magnetopause.

  12. Compact neutron flux monitor

    International Nuclear Information System (INIS)

    Madhavi, V.; Phatak, P.R.; Bahadur, C.; Bayala, A.K.; Jakati, R.K.; Sathian, V.

    2003-01-01

    Full text: A compact size neutron flux monitor has been developed incorporating standard boards developed for smart radiation monitors. The sensitivity of the monitors is 0.4cps/nV. It has been tested up to 2075 nV flux with standard neutron sources. It shows convincing results even in high flux areas like 6m away from the accelerator in RMC (Parel) for 106/107 nV. These monitors have a focal and remote display, alarm function with potential free contacts for centralized control and additional provision of connectivity via RS485/Ethernet. This paper describes the construction, working and results of the above flux monitor

  13. COMPARISON OF IMPLICIT SCHEMES TO SOLVE EQUATIONS OF RADIATION HYDRODYNAMICS WITH A FLUX-LIMITED DIFFUSION APPROXIMATION: NEWTON–RAPHSON, OPERATOR SPLITTING, AND LINEARIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Tetsu, Hiroyuki; Nakamoto, Taishi, E-mail: h.tetsu@geo.titech.ac.jp [Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551 (Japan)

    2016-03-15

    Radiation is an important process of energy transport, a force, and a basis for synthetic observations, so radiation hydrodynamics (RHD) calculations have occupied an important place in astrophysics. However, although the progress in computational technology is remarkable, their high numerical cost is still a persistent problem. In this work, we compare the following schemes used to solve the nonlinear simultaneous equations of an RHD algorithm with the flux-limited diffusion approximation: the Newton–Raphson (NR) method, operator splitting, and linearization (LIN), from the perspective of the computational cost involved. For operator splitting, in addition to the traditional simple operator splitting (SOS) scheme, we examined the scheme developed by Douglas and Rachford (DROS). We solve three test problems (the thermal relaxation mode, the relaxation and the propagation of linear waves, and radiating shock) using these schemes and then compare their dependence on the time step size. As a result, we find the conditions of the time step size necessary for adopting each scheme. The LIN scheme is superior to other schemes if the ratio of radiation pressure to gas pressure is sufficiently low. On the other hand, DROS can be the most efficient scheme if the ratio is high. Although the NR scheme can be adopted independently of the regime, especially in a problem that involves optically thin regions, the convergence tends to be worse. In all cases, SOS is not practical.

  14. Apparatus for the measurement of density-thickness by use of radiation

    International Nuclear Information System (INIS)

    Buchnea, A.

    1983-01-01

    The invention is used in on-line apparatus for continuously monitoring a property of a moving length of materials in which a source of radiation and a detector are mounted in spaced relationship at an on-line location at which the moving length is permitted to pass between the source and the detector. The invention involves an apparatus for calibrating the monitoring apparatus without moving the monitoring apparatus from the on-line location

  15. Laser radiation short pulse absorption in a high-density plasma

    International Nuclear Information System (INIS)

    Brantov, A.V.; Bychenkov, V.Yu.; Tikhonchuk, V.T.

    1998-01-01

    Dependences of the absorption coefficients for s and p polarized electromagnetic waves (laser radiation) in a semi-bound plasma on the temperature and incidence angle are found for an arbitrary ratio of the skin-layer depth to the electron free path length t. The dependences obtained describe transition from the normal skin effect to abnormal one and permit quantitatively to determine the absorption coefficients in the intermediate range of the parameter t, characteristic for the majority of modern experiments

  16. Assessment of 1D and 3D model simulated radiation flux based on surface measurements and estimation of aerosol forcing and their climatological aspects

    Science.gov (United States)

    Subba, T.; Gogoi, M. M.; Pathak, B.; Ajay, P.; Bhuyan, P. K.; Solmon, F.

    2018-05-01

    Ground reaching solar radiation flux was simulated using a 1-dimensional radiative transfer (SBDART) and a 3-dimensional regional climate (RegCM 4.4) model and their seasonality against simultaneous surface measurements carried out using a CNR4 net Radiometer over a sub-Himalayan foothill site of south-east Asia was assessed for the period from March 2013-January 2015. The model simulated incoming fluxes showed a very good correlation with the measured values with correlation coefficient R2 0.97. The mean bias errors between these two varied from -40 W m-2 to +7 W m-2 with an overestimation of 2-3% by SBDART and an underestimation of 2-9% by RegCM. Collocated measurements of the optical parameters of aerosols indicated a reduction in atmospheric transmission path by 20% due to aerosol load in the atmosphere when compared with the aerosol free atmospheric condition. Estimation of aerosol radiative forcing efficiency (ARFE) indicated that the presence of black carbon (BC, 10-15%) led to a surface dimming by -26.14 W m-2 τ-1 and a potential atmospheric forcing of +43.04 W m-2 τ-1. BC alone is responsible for >70% influence with a major role in building up of forcing efficiency of +55.69 W m-2 τ-1 (composite) in the atmosphere. On the other hand, the scattering due to aerosols enhance the outgoing radiation at the top of the atmosphere (ARFETOA -12.60 W m-2 ω-1), the absence of which would have resulted in ARFETOA of +16.91 W m-2 τ-1 (due to BC alone). As a result, 3/4 of the radiation absorption in the atmosphere is ascribed to the presence of BC. This translated to an atmospheric heating rate of 1.0 K day-1, with 0.3 K day-1 heating over the elevated regions (2-4 km) of the atmosphere, especially during pre-monsoon season. Comparison of the satellite (MODIS) derived and ground based estimates of surface albedo showed seasonal difference in their magnitudes (R2 0.98 during retreating monsoon and winter; 0.65 during pre-monsoon and monsoon), indicating that the

  17. A method of exploration of the atmosphere of Titan. [hot air balloon heated by solar radiation or planetary thermal flux

    Science.gov (United States)

    Blamont, J.

    1978-01-01

    A hot-air balloon, with the air heated by natural sources, is described. Buoyancy is accomplished by either solar heating or by utilizing the IR thermal flux of the planet to heat the gas in the balloon. Altitude control is provided by a valve which is opened and closed by a barometer. The balloon is made of an organic material which has to absorb radiant energy and to emit as little as possible.

  18. Cell damage from radiation-induced bystander effects for different cell densities simulated by a mathematical model via cellular automata

    Energy Technology Data Exchange (ETDEWEB)

    Meireles, Sincler P. de; Santos, Adriano M.; Grynberg, Suely Epsztein, E-mail: spm@cdtn.b, E-mail: amsantos@cdtn.b, E-mail: seg@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Nunes, Maria Eugenia S., E-mail: mariaeugenia@iceb.ufop.b [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)

    2011-07-01

    During recent years, there has been a shift from an approach focused entirely on DNA as the main target of ionizing radiation to a vision that considers complex signaling pathways in cells and among cells within tissues. Several newly recognized responses were classified as the so-called non-target responses in which the biological effects are not directly related to the amount of energy deposited in the DNA of cells that were traversed by radiation. In 1992 the bystander effect was described referring to a series of responses such as death, chromosomal instability or other abnormalities that occur in non-irradiated cells that came into contact with irradiated cells or medium from irradiated cells. In this work, we have developed a mathematical model via cellular automata, to quantify cell death induced by the bystander effect. The model is based on experiments with irradiated cells conditioned medium which suggests that irradiated cells secrete molecules in the medium that are capable of damaging other cells. The computational model consists of two-dimensional cellular automata which is able to simulate the transmission of bystander signals via extrinsic route and via Gap junctions. The model has been validated by experimental results in the literature. The time evolution of the effect and the dose-response curves were obtained in good accordance to them. Simulations were conducted for different values of bystander and irradiated cell densities with constant dose. From this work, we have obtained a relationship between cell density and effect. (author)

  19. Cell damage from radiation-induced bystander effects for different cell densities simulated by a mathematical model via cellular automata

    International Nuclear Information System (INIS)

    Meireles, Sincler P. de; Santos, Adriano M.; Grynberg, Suely Epsztein; Nunes, Maria Eugenia S.

    2011-01-01

    During recent years, there has been a shift from an approach focused entirely on DNA as the main target of ionizing radiation to a vision that considers complex signaling pathways in cells and among cells within tissues. Several newly recognized responses were classified as the so-called non-target responses in which the biological effects are not directly related to the amount of energy deposited in the DNA of cells that were traversed by radiation. In 1992 the bystander effect was described referring to a series of responses such as death, chromosomal instability or other abnormalities that occur in non-irradiated cells that came into contact with irradiated cells or medium from irradiated cells. In this work, we have developed a mathematical model via cellular automata, to quantify cell death induced by the bystander effect. The model is based on experiments with irradiated cells conditioned medium which suggests that irradiated cells secrete molecules in the medium that are capable of damaging other cells. The computational model consists of two-dimensional cellular automata which is able to simulate the transmission of bystander signals via extrinsic route and via Gap junctions. The model has been validated by experimental results in the literature. The time evolution of the effect and the dose-response curves were obtained in good accordance to them. Simulations were conducted for different values of bystander and irradiated cell densities with constant dose. From this work, we have obtained a relationship between cell density and effect. (author)

  20. Supercritical CO2 foaming of radiation crosslinked polypropylene/high-density polyethylene blend: Cell structure and tensile property

    Science.gov (United States)

    Yang, Chenguang; Xing, Zhe; Zhang, Mingxing; Zhao, Quan; Wang, Mouhua; Wu, Guozhong

    2017-12-01

    A blend of isotactic polypropylene (PP) with high-density polyethylene (HDPE) in different PP/HDPE ratios was irradiated by γ-ray to induce cross-linking and then foamed using supercritical carbon dioxide (scCO2) as a blowing agent. Radiation effect on the melting point and crystallinity were analyzed in detail. The average cell diameter and cell density were compared for PP/HDPE foams prepared under different conditions. The optimum absorbed dose for the scCO2 foaming of PP/HDPE in terms of foaming ability and cell structure was 20 kGy. Tensile measurements showed that the elongation at break and tensile strength at break of the crosslinked PP/HDPE foams were higher than the non-crosslinked ones. Of particular interest was the increase in the foaming temperature window from 4 ℃ for pristine PP to 8-12 ℃ for the radiation crosslinked PP/HDPE blends. This implies much easier handling of scCO2 foaming of crosslinked PP with the addition of HDPE.