WorldWideScience

Sample records for higher flux densities

  1. TRIGA research reactors with higher power density

    International Nuclear Information System (INIS)

    Whittemore, W.L.

    1994-01-01

    The recent trend in new or upgraded research reactors is to higher power densities (hence higher neutron flux levels) but not necessarily to higher power levels. The TRIGA LEU fuel with burnable poison is available in small diameter fuel rods capable of high power per rod (≅48 kW/rod) with acceptable peak fuel temperatures. The performance of a 10-MW research reactor with a compact core of hexagonal TRIGA fuel clusters has been calculated in detail. With its light water coolant, beryllium and D 2 O reflector regions, this reactor can provide in-core experiments with thermal fluxes in excess of 3 x 10 14 n/cm 2 ·s and fast fluxes (>0.1 MeV) of 2 x 10 14 n/cm 2 ·s. The core centerline thermal neutron flux in the D 2 O reflector is about 2 x 10 14 n/cm 2 ·s and the average core power density is about 230 kW/liter. Using other TRIGA fuel developed for 25-MW test reactors but arranged in hexagonal arrays, power densities in excess of 300 kW/liter are readily available. A core with TRIGA fuel operating at 15-MW and generating such a power density is capable of producing thermal neutron fluxes in a D 2 O reflector of 3 x 10 14 n/cm 2 ·s. A beryllium-filled central region of the core can further enhance the core leakage and hence the neutron flux in the reflector. (author)

  2. 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...

  3. 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.

  4. 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.

  5. Batteries. Higher energy density than gasoline?

    International Nuclear Information System (INIS)

    Fischer, Michael; Werber, Mathew; Schwartz, Peter V.

    2009-01-01

    The energy density of batteries is two orders of magnitude below that of liquid fuels. However, this information alone cannot be used to compare batteries to liquid fuels for automobile energy storage media. Because electric motors have a higher energy conversion efficiency and lower mass than combustion engines, they can provide a higher deliverable mechanical energy density than internal combustion for most transportation applications. (author)

  6. The higher order flux mapping method in large size PHWRs

    International Nuclear Information System (INIS)

    Kulkarni, A.K.; Balaraman, V.; Purandare, H.D.

    1997-01-01

    A new higher order method is proposed for obtaining flux map using single set of expansion mode. In this procedure, one can make use of the difference between predicted value of detector reading and their actual values for determining the strength of local fluxes around detector site. The local fluxes are arising due to constant perturbation changes (both extrinsic and intrinsic) taking place in the reactor. (author)

  7. 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)

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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...

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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)

  20. 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.

  1. 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)

  2. 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...

  3. 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...

  4. 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

  5. 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.

  6. 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)

  7. 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

  8. 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.

  9. 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/...

  10. 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.

  11. 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

  12. 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

  13. Higher order Cambell techniques for neutron flux measurement. Pt. 1

    International Nuclear Information System (INIS)

    Lux, I.; Baranyai, A.

    1982-01-01

    An exact mathematical description of arbitrary high order Campbell techniques for measuring particle fluxes is given. The nth order Campbell technique assumes the measurement of the moments of the outcoming voltage up to the nth one. A simple relation is derived among the various moments of the total measured voltage and of the detector signal caused by one incident particle. It is proven that in the monoparticle case combination of the measured moments up to the order n provides an expression proportional to the particle flux and to the nth moment of the detector signal. Generalization to several different particles is given and it is shown that if the flux of the particle causing the largest detector signal is measured with a relative error epsilon in the dc method and the error is due to the signals of other particles, then in the nth order campbelling the error will be of order epsilonsup(n). The effect of a random background on the measured voltage is also investigated and it is established that the nth order campbelling supresses the noise according to the nth power of the relative amplitude of the noise to the signal. The results concerning constant fluxes are generalized to time dependent particle fluxes and a method assuming a Fourier transform of the measured quantities is proposed for their determination. (orig.)

  14. 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...

  15. 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

  16. 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.

  17. 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.)

  18. 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

  19. 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

  20. 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.

  1. 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

  2. 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

  3. 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

  4. 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.

  5. 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...

  6. 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

  7. 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

  8. 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

  9. 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...

  10. 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)

  11. 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.

  12. Extended Opacity Tables with Higher Temperature-Density-Frequency Resolution

    Science.gov (United States)

    Schillaci, Mark; Orban, Chris; Delahaye, Franck; Pinsonneault, Marc; Nahar, Sultana; Pradhan, Anil

    2015-05-01

    Theoretical models for plasma opacities underpin our understanding of radiation transport in many different astrophysical objects. These opacity models are also relevant to HEDP experiments such as ignition scale experiments on NIF. We present a significantly expanded set of opacity data from the widely utilized Opacity Project, and make these higher resolution data publicly available through OSU's portal with dropbox.com. This expanded data set is used to assess how accurate the interpolation of opacity data in temperature-density-frequency dimensions must be in order to adequately model the properties of most stellar types. These efforts are the beginning of a larger project to improve the theoretical opacity models in light of experimental results at the Sandia Z-pinch showing that the measured opacity of Iron disagrees strongly with all current models.

  13. 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.

  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. 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

  16. 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.

  17. 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

  18. 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)

  19. 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)

  20. 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)

  1. 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.

  2. 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

  3. 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

  4. 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...

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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

    measurements using the HFD-measured radial profiles. The standard TDP daily mean of sap-flux density was 95% higher than the 2cm equivalent of the HFD for Q. ilex and 70% higher for Q. pyrenaica. NTG-corrected TDP daily mean of sap-flux density was 34% higher than HFD for Q. ilex and 47% lower for Q. pyrenaica. Regarding sap flow measurements, the standard TDP sap flow was 81% higher than HFD sap flow for Q. ilex and 297% for Q. pyrenaica. The NTG-corrected TDP sap flow was 24% higher than HFD sap flow for Q. ilex and 23% for Q. pyrenaica. The radial correction, for TDP-NTG-corrected sap-flux density, produced sap-flow measurements in well agreement with HFD, just slightly lower (-3% Q.i. and -4% Q.p.). The TDP-HFD sap flow data acquired in dry season over the savanna type of sparsely distributed oak trees (Q. ilex & Q. pyrenaica) showed that the TDP method must be corrected for NTG and for radial variability of sap flux density in trees with sapwood thicker than 2 cm. If such corrections are not taken into consideration, the amount of accounted water used by the trees is prone to overestimation, especially for Quercus pyrenaica. The obtained results indicate also that the combination of HFD and TDP leads to an efficient and accurate operational sap flow measurement schema that is currently in the optimization stage.

  10. Higher insulin sensitivity in vegans is not associated with higher mitochondrial density.

    Science.gov (United States)

    Gojda, J; Patková, J; Jaček, M; Potočková, J; Trnka, J; Kraml, P; Anděl, M

    2013-12-01

    Vegans have a lower incidence of insulin resistance (IR)-associated diseases and a higher insulin sensitivity (IS) compared with omnivores. The aim of this study was to examine whether the higher IS in vegans relates to markers of mitochondrial biogenesis and to intramyocellular lipid (IMCL) content. Eleven vegans and 10 matched (race, age, sex, body mass index, physical activity and energy intake) omnivorous controls were enrolled in a case-control study. Anthropometry, bioimpedance (BIA), ultrasound measurement of visceral and subcutaneous fat layer, parameters of glucose and lipid homeostasis, hyperinsulinemic euglycemic clamp and muscle biopsies were performed. Citrate synthase (CS) activity, mitochondrial DNA (mtDNA) and IMCL content were assessed in skeletal muscle samples. Both groups were comparable in anthropometric and BIA parameters, physical activity and protein-energy intake. Vegans had significantly higher glucose disposal (M-value, vegans 8.11±1.51 vs controls 6.31±1.57 mg/kg/min, 95% confidence interval: 0.402 to 3.212, P=0.014), slightly lower IMCL content (vegans 13.91 (7.8 to 44.0) vs controls 17.36 (12.4 to 78.5) mg/g of muscle, 95% confidence interval: -7.594 to 24.550, P=0.193) and slightly higher relative muscle mtDNA amount (vegans 1.36±0.31 vs controls 1.13±0.36, 95% confidence interval:-0.078 to 0.537, P=0.135). No significant differences were found in CS activity (vegans 18.43±5.05 vs controls 18.16±5.41 μmol/g/min, 95% confidence interval: -4.503 to 5.050, P=0.906). Vegans have a higher IS, but comparable mitochondrial density and IMCL content with omnivores. This suggests that a decrease in whole-body glucose disposal may precede muscle lipid accumulation and mitochondrial dysfunction in IR development.

  11. Higher-order relationship between eigen-value separation and static flux tilts

    International Nuclear Information System (INIS)

    Beckner, W.D.

    1975-01-01

    Spatial kinetics phenomena in nuclear reactors, such as xenon-induced spatial flux oscillations, are currently being analyzed using the higher harmonic solutions to the static reactor balance equation. An important parameter in such an analysis is a global quantity called eigenvalue separation. It is desirable to be able to experimentally measure this parameter in power reactors in order to confirm design calculations. Since spatial distortions in the flux shape depend on the eigenvalue separation of the reactor, an attempt has been made previously to use this fact as a means of measuring the parameter. It was postulated that an induced flux distortion or ''static flux tilt'' could be measured and theoretically related to eigenvalue separation. Unfortunately, the behavior of experimental data did not exactly agree with theoretical predictions, and values of the parameter found using the original static flux tilt technique were consistently low. The theory has been re-evaluated here and the previously observed discrepancy eliminated. Techniques have been also developed to allow for more accurate interpretation of experimental data. In order to make the method applicable to real systems, the theory has been extended to two spatial dimensions; extension to three dimensions follows directly. Possible trouble areas have been investigated, and experimental procedures for use of the technique to measure the eigenvalue separation in power reactors are presented

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Higher-accuracy van der Waals density functional

    DEFF Research Database (Denmark)

    Lee, Kyuho; Murray, Éamonn D.; Kong, Lingzhu

    2010-01-01

    We propose a second version of the van der Waals density functional of Dion et al. [Phys. Rev. Lett. 92, 246401 (2004)], employing a more accurate semilocal exchange functional and the use of a large-N asymptote gradient correction in determining the vdW kernel. The predicted binding energy...

  17. 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

  18. 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

  19. 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

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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

  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. 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

  16. 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)

  17. 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.

  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. 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.

  20. 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.

  1. 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

  2. Applying Brand Management to Higher Education through the Use of the Brand Flux Model™--The Case of Arcadia University

    Science.gov (United States)

    Williams, Robert L., Jr.; Omar, Maktoba

    2014-01-01

    Within an increasingly more competitive landscape, Higher Education Institutions (HEIs) are becoming more marketized and promotionalized. Brand building is becoming a strategic administrative goal, yet clear brand management models are lacking. This paper utilizes the Brand Flux Model™ to assist in tracking the fluxing nature or historical…

  3. 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...

  4. 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)

  5. 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.

  6. 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.)

  7. 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.)

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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...

  14. 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.

  15. 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)

  16. 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)

  17. 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.

  18. 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)

  19. Spatially resolved flux measurements of NOx from London suggest significantly higher emissions than predicted by inventories.

    Science.gov (United States)

    Vaughan, Adam R; Lee, James D; Misztal, Pawel K; Metzger, Stefan; Shaw, Marvin D; Lewis, Alastair C; Purvis, Ruth M; Carslaw, David C; Goldstein, Allen H; Hewitt, C Nicholas; Davison, Brian; Beevers, Sean D; Karl, Thomas G

    2016-07-18

    To date, direct validation of city-wide emissions inventories for air pollutants has been difficult or impossible. However, recent technological innovations now allow direct measurement of pollutant fluxes from cities, for comparison with emissions inventories, which are themselves commonly used for prediction of current and future air quality and to help guide abatement strategies. Fluxes of NOx were measured using the eddy-covariance technique from an aircraft flying at low altitude over London. The highest fluxes were observed over central London, with lower fluxes measured in suburban areas. A footprint model was used to estimate the spatial area from which the measured emissions occurred. This allowed comparison of the flux measurements to the UK's National Atmospheric Emissions Inventory (NAEI) for NOx, with scaling factors used to account for the actual time of day, day of week and month of year of the measurement. The comparison suggests significant underestimation of NOx emissions in London by the NAEI, mainly due to its under-representation of real world road traffic emissions. A comparison was also carried out with an enhanced version of the inventory using real world driving emission factors and road measurement data taken from the London Atmospheric Emissions Inventory (LAEI). The measurement to inventory agreement was substantially improved using the enhanced version, showing the importance of fully accounting for road traffic, which is the dominant NOx emission source in London. In central London there was still an underestimation by the inventory of 30-40% compared with flux measurements, suggesting significant improvements are still required in the NOx emissions inventory.

  20. 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.

  1. 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.

  2. 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

  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. 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. 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.

  7. 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.

  8. 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

  9. LDPC coding for QKD at higher photon flux levels based on spatial entanglement of twin beams in PDC

    International Nuclear Information System (INIS)

    Daneshgaran, Fred; Mondin, Marina; Bari, Inam

    2014-01-01

    Twin beams generated by Parametric Down Conversion (PDC) exhibit quantum correlations that has been effectively used as a tool for many applications including calibration of single photon detectors. By now, detection of multi-mode spatial correlations is a mature field and in principle, only depends on the transmission and detection efficiency of the devices and the channel. In [2, 4, 5], the authors utilized their know-how on almost perfect selection of modes of pairwise correlated entangled beams and the optimization of the noise reduction to below the shot-noise level, for absolute calibration of Charge Coupled Device (CCD) cameras. The same basic principle is currently being considered by the same authors for possible use in Quantum Key Distribution (QKD) [3, 1]. The main advantage in such an approach would be the ability to work with much higher photon fluxes than that of a single photon regime that is theoretically required for discrete variable QKD applications (in practice, very weak laser pulses with mean photon count below one are used).The natural setup of quantization of CCD detection area and subsequent measurement of the correlation statistic needed to detect the presence of the eavesdropper Eve, leads to a QKD channel model that is a Discrete Memoryless Channel (DMC) with a number of inputs and outputs that can be more than two (i.e., the channel is a multi-level DMC). This paper investigates the use of Low Density Parity Check (LDPC) codes for information reconciliation on the effective parallel channels associated with the multi-level DMC. The performance of such codes are shown to be close to the theoretical limits.

  10. 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.

  11. Impact of CLAS and COMPASS data on polarized parton densities and higher twist

    International Nuclear Information System (INIS)

    Leader, Elliot; Sidorov, Aleksander V.; Stamenov, Dimiter B.

    2007-01-01

    We have reanalyzed the world data on inclusive polarized deep inelastic scattering (DIS) including the very precise CLAS proton and deuteron data, as well as the latest COMPASS data on the asymmetry A 1 d , and have studied the impact of these data on polarized parton densities and higher twist effects. We demonstrate that the low Q 2 CLAS data improve essentially our knowledge of higher twist corrections to the spin structure function g 1 , while the large Q 2 COMPASS data influence mainly the strange quark density. In our new analysis we find that a negative polarized gluon density, or one that changes sign as a function of x, cannot be ruled out on the basis of the present DIS data

  12. 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.

  13. Higher glandular trichome density in tomato leaflets and repellence to spider mites

    International Nuclear Information System (INIS)

    Maluf, Wilson Roberto; Inoue, Irene Fumi; Ferreira, Raphael de Paula Duarte; Gomes, Luiz Antonio Augusto; Castro, Evaristo Mauro de; Cardoso, Maria das Gracas

    2007-01-01

    The objective of this work was to evaluate the feasibility of selection for higher glandular trichome densities, as an indirect criterion of selection for increasing repellence to spider mites Tetranychus urticae, in tomato populations derived from an interspecific cross between Lycopersicon esculentum x L. hirsutum var. glabratum PI 134417. Trichome densities were evaluated in 19 genotypes, including 12 from advanced backcross populations, derived from the original cross L. esculentum x L. hirsutum var. glabratum PI 134417. Counts were made both on the adaxial and abaxial leaf surfaces, and trichomes were classified into glandular types IV and VI, other glandular types (types I+VII), and nonglandular types. Mite repellence was measured by distances walked by mites onto the tomato leaf surface after 20, 40 and 60 min. Spider mite repellence biotests indicated that higher densities of glandular trichomes (especially type VI) decreased the distances walked by the mites onto the tomato leaf surface. Selection of plants with higher densities of glandular trichomes can be an efficient criterion to obtain tomato genotypes with higher resistance (repellence) to spider mites. (author)

  14. 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

  15. 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.

  16. 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

  17. 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).

  18. Use of higher order signal moments and high speed digital sampling technique for neutron flux measurements

    Science.gov (United States)

    Baers, L. B.; Gutierrez, T. Rivero; Mendoza, R. A. Carrillo; Santana, G. Jimenez

    1993-08-01

    The second (conventional variance or Campbell signal), the third, and the modified fourth order central signal moments associated with the amplified and filtered currents from two electrodes of an ex-core neutron sensitive fission detector were measured versus the reactor power of the 1-MW TRIGA reactor in Mexico City. Two channels of a high-speed (400-MHz) multiplexing data sampler and an analog-to-digital converter with 12-b resolution and 1-Mword buffer memory were used. The data were further retrieved into a PC, and estimates for autocorrelation and cross-correlation moments up to the fifth order, coherence, skewness, excess, etc., quantities were calculated offline. Five-mode operation of the detector was achieved, including conventional counting rates and currents in agreement with theory and the authors' previous results with analog techniques. The signals are proportional to the neutron flux and reactor power in some flux ranges. The suppression of background noise is improved and the lower limit of the measurement range is extended as the order of moment is increased, in agreement with theory.

  19. 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.

  20. 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.

  1. A comparison of different methods to implement higher order derivatives of density functionals

    Energy Technology Data Exchange (ETDEWEB)

    van Dam, Hubertus J.J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-05-18

    Density functional theory is the dominant approach in electronic structure methods today. To calculate properties higher order derivatives of the density functionals are required. These derivatives might be implemented manually,by automatic differentiation, or by symbolic algebra programs. Different authors have cited different reasons for using the particular method of their choice. This paper presents work where all three approaches were used and the strengths and weaknesses of each approach are considered. It is found that all three methods produce code that is suffficiently performanted for practical applications, despite the fact that our symbolic algebra generated code and our automatic differentiation code still have scope for significant optimization. The automatic differentiation approach is the best option for producing readable and maintainable code.

  2. Higher-order terms in the nuclear-energy-density functional

    International Nuclear Information System (INIS)

    Carlsson, B. G.; Borucki, M.; Dobaczewski, J.

    2009-01-01

    One of the current projects at the Department of Physics in the University of Jyvaeskylae is to explore more general forms of the Skyrme energy-density functional (EDF). The aim is to find new phenomenological terms which are sensitive to experimental data. In this context we have extended the Skyrme functional by including terms which contain higher orders of derivatives allowing for a better description of finite range effects. This was done by employing an expansion in derivatives in a spherical-tensor formalism [1] motivated by ideas of the density-matrix expansion. The resulting functionals have different number of free parameters depending on the order in derivatives and assumed symmetries, see Fig. 1. The usual Skyrme EDF is obtained as a second order expansion while we keep terms up to sixth order.(author)

  3. The Dynamic Flux of Continuing Higher Education: Redefining the New Roles, Responsibilities, and Expectations

    Science.gov (United States)

    Braverman, Lisa R.

    2013-01-01

    Continuing higher education has undergone a significant transformation in recent years, illustrated by such innovations as MOOCs, globalization, strategic collaborations with government and industry, and increased entrepreneurship. As a result, continuing education (CE) units have experienced a fundamental shift in the way they conduct business in…

  4. Computation of higher spherical harmonics moments of the angular flux for neutron transport problems in spherical geometry

    International Nuclear Information System (INIS)

    Sahni, D.C.; Sharma, A.

    2000-01-01

    The integral form of one-speed, spherically symmetric neutron transport equation with isotropic scattering is considered. Two standard problems are solved using normal mode expansion technique. The expansion coefficients are obtained by solving their singular integral equations. It is shown that these expansion coefficients provide a representation of all spherical harmonics moments of the angular flux as a superposition of Bessel functions. It is seen that large errors occur in the computation of higher moments unless we take certain precautions. The reasons for this phenomenon are explained. They throw some light on the failure of spherical harmonics method in treating spherical geometry problems as observed by Aronsson

  5. Fractional equivalent Lagrangian densities for a fractional higher-order equation

    International Nuclear Information System (INIS)

    Fujioka, J

    2014-01-01

    In this communication we show that the equivalent Lagrangian densities (ELDs) of a fractional higher-order nonlinear Schrödinger equation with stable soliton-like solutions can be related in a hitherto unknown way. This new relationship is described in terms of a new fractional operator that includes both left- and right-sided fractional derivatives. Using this operator it is possible to generate new ELDs that contain different fractional parts, in addition to the already known ELDs, which only differ by a sum of first-order partial derivatives of two arbitrary functions. (fast track communications)

  6. Higher-order anisotropies in the blast-wave model: Disentangling flow and density field anisotropies

    Energy Technology Data Exchange (ETDEWEB)

    Cimerman, Jakub [Czech Technical University in Prague, FNSPE, Prague (Czech Republic); Comenius University, FMPI, Bratislava (Slovakia); Tomasik, Boris [Czech Technical University in Prague, FNSPE, Prague (Czech Republic); Univerzita Mateja Bela, FPV, Banska Bystrica (Slovakia); Csanad, Mate; Loekoes, Sandor [Eoetvoes Lorand University, Budapest (Hungary)

    2017-08-15

    We formulate a generalisation of the blast-wave model which is suitable for the description of higher-order azimuthal anisotropies of the hadron production. The model includes anisotropy in the density profile as well as an anisotropy in the transverse expansion velocity field. We then study how these two kinds of anisotropies influence the single-particle distributions and the correlation radii of two-particle correlation functions. Particularly we focus on the third-order anisotropy and consideration is given averaging over different orientations of the event plane. (orig.)

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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...

  12. Transition of EMRIs through resonance: higher order corrections in resonant flux enhancement

    Science.gov (United States)

    Mihaylov, Deyan; Gair, Jonathan

    2017-01-01

    Extreme mass ratio inspirals (EMRIs) are candidate events for gravitational wave detection in the millihertz range (by detectors like LISA and eLISA). These events involve a stellar-mass black hole, or a similar compact object, descending into the gravitational field of a supermassive black hole, eventually merging with it. Properties of the inspiraling trajectory away from resonance are well known and have been studied extensively, however little is known about the behaviour of these binary systems at resonance, when the radial and lateral frequencies of the orbit become commensurate. There are two resonance models in the literature, the instantaneous frequency function by Gair, Bender, and Yunes, and the standard two timescales approach devised by Flanagan and Hinderer. We argue that the Gair, Bender and Yunes model provides a valid treatment of the resonance problem and extend this solution to higher order in the size of the on-resonance perturbation. The non-linear differential equations which arise in treating resonances are interesting from a mathematical view point. We present our algorithm for perturbative solutions and the results to third order in the infinitesimal parameter, and discuss the scope of this approach. Deyan Mihaylov is funded by the STFC.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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)%)

  4. Higher Dietary Energy Density is Associated with Stunting but not Overweight and Obesity in a Sample of Urban Malaysian Children.

    Science.gov (United States)

    Shariff, Zalilah Mohd; Lin, Khor Geok; Sariman, Sarina; Siew, Chin Yit; Yusof, Barakatun Nisak Mohd; Mun, Chan Yoke; Lee, Huang Soo; Mohamad, Maznorila

    2016-01-01

    Although diets with high energy density are associated with increased risk of overweight and obesity, it is not known whether such diets are associated with undernutrition. This study assessed the relationship between dietary energy density (ED) and nutritional status of 745 urban 1- to 10-year-old children. Dietary intakes were obtained using food recall and record for two days. Dietary energy density was based on food and caloric beverages. Higher dietary ED was associated with lower intakes of carbohydrate, sugar, vitamins C and D, and calcium but higher fat, fiber, iron, and folate intakes. While intakes of fruits and milk/dairy products decreased, meat, fish, and legume intakes increased with higher dietary ED. Stunting, but not other growth problems, was associated with higher dietary ED. Future studies should confirm the cause-and-effect relationship between higher dietary ED and stunting.

  5. 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

  6. 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

  7. Preliminary Modelling of Mass Flux at the Surface of Plant Leaves within the MELiSSA Higher Plant Compartments

    Science.gov (United States)

    Holmberg, Madeleine; Paille, Christel; Lasseur, Christophe

    The ESA project Micro Ecological Life Support System Alternative (MELiSSA) is an ecosystem of micro-organisms and higher plants, constructed with the objective of being operated as a tool to understand artificial ecosystems to be used for a long-term or permanent manned planetary base (e.g. Moon or Mars). The purpose of such a system is to provide for generation of food, water recycling, atmospheric regeneration and waste management within defined standards of quality and reliability. As MELiSSA consists of individual compartments which are connected to each other, the robustness of the system is fully dependent on the control of each compartment, as well as the flow management between them. Quality of consumables and reliability of the ecosystem rely on the knowledge, understanding and control of each of the components. This includes the full understanding of all processes related to the higher plants. To progress in that direction, this paper focuses on the mechanical processes driving the gas and liquid exchanges between the plant leaf and its environment. The process responsible for the mass transfer on the surface of plant leaves is diffusion. The diffusion flux is dependent on the behaviour of the stoma of the leaf and also on the leaf boundary layer (BL). In this paper, the physiology of the leaf is briefly examined in order to relate parameters such as light quality, light quantity, CO2 concentration, temperature, leaf water potential, humidity, vapour pressure deficit (VPD) gradients and pollutants to the opening or closing of stomata. The diffusion process is described theoretically and the description is compared to empirical approaches. The variables of the BL are examined and the effect airflow in the compartment has on the BL is investigated. Also presented is the impact changes in different environmental parameters may have on the fluid exchanges. Finally, some tests, to evaluate the accuracy of the concluded model, are suggested.

  8. 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.

  9. 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)

  10. 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

  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. Obesity-related eating behaviors are associated with higher food energy density and higher consumption of sugary and alcoholic beverages: a cross-sectional study.

    Science.gov (United States)

    Muñoz-Pareja, Maritza; Guallar-Castillón, Pilar; Mesas, Arthur E; López-García, Esther; Rodríguez-Artalejo, Fernando

    2013-01-01

    Obesity-related eating behaviors (OREB) are associated with higher energy intake. Total energy intake can be decomposed into the following constituents: food portion size, food energy density, the number of eating occasions, and the energy intake from energy-rich beverages. To our knowledge this is the first study to examine the association between the OREB and these energy components. Data were taken from a cross-sectional study conducted in 2008-2010 among 11,546 individuals representative of the Spanish population aged ≥ 18 years. Information was obtained on the following 8 self-reported OREB: not planning how much to eat before sitting down, eating precooked/canned food or snacks bought at vending machines or at fast-food restaurants, not choosing low-energy foods, not removing visible fat from meat or skin from chicken, and eating while watching TV. Usual diet was assessed with a validated diet history. Analyses were performed with linear regression with adjustment for main confounders. Compared to individuals with ≤ 1 OREB, those with ≥ 5 OREB had a higher food energy density (β 0.10; 95% CI 0.08, 0.12 kcal/g/day; p-trendassociated with higher intake of dairy products and red meat, and with lower consumption of fresh fruit, oily fish and white meat. No association was found between the number of OREB and food portion size or the number of eating occasions. OREB were associated with higher food energy density and higher consumption of sugary and alcoholic beverages. Avoiding OREB may prove difficult because they are firmly socially rooted, but these results may nevertheless serve to palliate the undesirable effects of OREB by reducing the associated energy intake.

  13. REM sleep behaviour disorder is associated with lower fast and higher slow sleep spindle densities.

    Science.gov (United States)

    O'Reilly, Christian; Godin, Isabelle; Montplaisir, Jacques; Nielsen, Tore

    2015-12-01

    To investigate differences in sleep spindle properties and scalp topography between patients with rapid eye movement sleep behaviour disorder (RBD) and healthy controls, whole-night polysomnograms of 35 patients diagnosed with RBD and 35 healthy control subjects matched for age and sex were compared. Recordings included a 19-lead 10-20 electroencephalogram montage and standard electromyogram, electrooculogram, electrocardiogram and respiratory leads. Sleep spindles were automatically detected using a standard algorithm, and their characteristics (amplitude, duration, density, frequency and frequency slope) compared between groups. Topological analyses of group-discriminative features were conducted. Sleep spindles occurred at a significantly (e.g. t34 = -4.49; P = 0.00008 for C3) lower density (spindles ∙ min(-1) ) for RBD (mean ± SD: 1.61 ± 0.56 for C3) than for control (2.19 ± 0.61 for C3) participants. However, when distinguishing slow and fast spindles using thresholds individually adapted to the electroencephalogram spectrum of each participant, densities smaller (31-96%) for fast but larger (20-120%) for slow spindles were observed in RBD in all derivations. Maximal differences were in more posterior regions for slow spindles, but over the entire scalp for fast spindles. Results suggest that the density of sleep spindles is altered in patients with RBD and should therefore be investigated as a potential marker of future neurodegeneration in these patients. © 2015 European Sleep Research Society.

  14. 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)

  15. Immunity of an alternative host can be overcome by higher densities of its parasitoids Palmistichus elaeisis and Trichospilus diatraeae.

    Directory of Open Access Journals (Sweden)

    Gilberto Santos Andrade

    Full Text Available Interactions of the parasitoids Palmistichus elaeisis Delvare & LaSalle and Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae with its alternative host Anticarsia gemmatalis (Hübner (Lepidoptera: Noctuidae affect the success or failure of the mass production of these parasitoids for use in integrated pest management programs. The aim of this study was to evaluate changes in the cellular defense and encapsulation ability of A. gemmatalis pupae against P. elaeisis or T. diatraeae in adult parasitoid densities of 1, 3, 5, 7, 9, 11 or 13 parasitoids/pupae. We evaluated the total quantity of circulating hemocytes and the encapsulation rate versus density. Increasing parasitoid density reduced the total number of hemocytes in the hemolymph and the encapsulation rate by parasitized pupae. Furthermore, densities of P. elaeisis above 5 parasitoids/pupae caused higher reduction in total hemocyte numbers. The encapsulation rate fell with increasing parasitoid density. However, parasitic invasion by both species induced generally similar responses. The reduction in defensive capacity of A. gemmatalis is related to the adjustment of the density of these parasitoids to their development in this host. Thus, the role of the density of P. elaeisis or T. diatraeae by pupa is induced suppression of cellular defense and encapsulation of the host, even without them possesses a co-evolutionary history. Furthermore, these findings can predict the success of P. elaeisis and T. diatraeae in the control of insect pests through the use of immunology as a tool for evaluation of natural enemies.

  16. Agrochemicals increase risk of human schistosomiasis by supporting higher densities of intermediate hosts.

    Science.gov (United States)

    Halstead, Neal T; Hoover, Christopher M; Arakala, Arathi; Civitello, David J; De Leo, Giulio A; Gambhir, Manoj; Johnson, Steve A; Jouanard, Nicolas; Loerns, Kristin A; McMahon, Taegan A; Ndione, Raphael A; Nguyen, Karena; Raffel, Thomas R; Remais, Justin V; Riveau, Gilles; Sokolow, Susanne H; Rohr, Jason R

    2018-02-26

    Schistosomiasis is a snail-borne parasitic disease that ranks among the most important water-based diseases of humans in developing countries. Increased prevalence and spread of human schistosomiasis to non-endemic areas has been consistently linked with water resource management related to agricultural expansion. However, the role of agrochemical pollution in human schistosome transmission remains unexplored, despite strong evidence of agrochemicals increasing snail-borne diseases of wildlife and a projected 2- to 5-fold increase in global agrochemical use by 2050. Using a field mesocosm experiment, we show that environmentally relevant concentrations of fertilizer, a herbicide, and an insecticide, individually and as mixtures, increase densities of schistosome-infected snails by increasing the algae snails eat and decreasing densities of snail predators. Epidemiological models indicate that these agrochemical effects can increase transmission of schistosomes. Identifying agricultural practices or agrochemicals that minimize disease risk will be critical to meeting growing food demands while improving human wellbeing.

  17. Double-layer capacitors with a higher energy density; Doppelschichtkondensatoren mit hoeherem Energieinhalt

    Energy Technology Data Exchange (ETDEWEB)

    Presser, Volker [Leibniz-Institut fuer Neue Materialien (INM) gGmbH, Saarbruecken (Germany). Juniorforschungs-Gruppe Energie-Materialien; Universitaet des Saarlandes, Saarbruecken (Germany)

    2013-05-15

    Electrical double-layer capacitors, also known as supercapacitors (SC) are devices for electrical energy storage used for fast acceleration of hybrid cars or for the energy recovery during breaking operations. In contrast, lithium-ion batteries (LIB) are used as energy storage devices to provide an extended travel distance for plug-in hybrid cars and electric vehicles. Current research aims to overcome the major limitations of both technologies (SC: low energy density/LIB: slow recharge and limited service life) and hybrid cells are considered a promising solution. The goal is to improve the performance and energy density of storage devices which can be achieved, as shown by the Leibniz-Institute for New Materials (INM), with the use of nanotechnology. (orig.)

  18. Obesity-related eating behaviors are associated with higher food energy density and higher consumption of sugary and alcoholic beverages: a cross-sectional study.

    Directory of Open Access Journals (Sweden)

    Maritza Muñoz-Pareja

    Full Text Available Obesity-related eating behaviors (OREB are associated with higher energy intake. Total energy intake can be decomposed into the following constituents: food portion size, food energy density, the number of eating occasions, and the energy intake from energy-rich beverages. To our knowledge this is the first study to examine the association between the OREB and these energy components.Data were taken from a cross-sectional study conducted in 2008-2010 among 11,546 individuals representative of the Spanish population aged ≥ 18 years. Information was obtained on the following 8 self-reported OREB: not planning how much to eat before sitting down, eating precooked/canned food or snacks bought at vending machines or at fast-food restaurants, not choosing low-energy foods, not removing visible fat from meat or skin from chicken, and eating while watching TV. Usual diet was assessed with a validated diet history. Analyses were performed with linear regression with adjustment for main confounders.Compared to individuals with ≤ 1 OREB, those with ≥ 5 OREB had a higher food energy density (β 0.10; 95% CI 0.08, 0.12 kcal/g/day; p-trend<0.001 and a higher consumption of sugary drinks (β 7; 95% CI -7, 20 ml/day; p-trend<0.05 and of alcoholic beverages (β 24; 95% CI 10, 38 ml/day; p-trend<0.001. Specifically, a higher number of OREB was associated with higher intake of dairy products and red meat, and with lower consumption of fresh fruit, oily fish and white meat. No association was found between the number of OREB and food portion size or the number of eating occasions.OREB were associated with higher food energy density and higher consumption of sugary and alcoholic beverages. Avoiding OREB may prove difficult because they are firmly socially rooted, but these results may nevertheless serve to palliate the undesirable effects of OREB by reducing the associated energy intake.

  19. The Grenoble station for producing strong transient magnetic fields higher than 100 teslas by an explosive driven flux compression

    International Nuclear Information System (INIS)

    Guillot, M.

    1976-01-01

    Reproducible transient magnetic fields up to 400 teslas (4 megaoersted) are achieved by a simple explosive driven flux compression. The results are described simply from the point of view of energy conversion. The problems of field measurements are studied: the precision is +-2% with a field cavity of 5 mm diameter [fr

  20. Surface Casimir densities and induced cosmological constant in higher dimensional braneworlds

    International Nuclear Information System (INIS)

    Saharian, Aram A.

    2006-01-01

    We investigate the vacuum expectation value of the surface energy-momentum tensor for a massive scalar field with general curvature coupling parameter obeying the Robin boundary conditions on two codimension one parallel branes in a (D+1)-dimensional background spacetime AdS D 1 +1 xΣ with a warped internal space Σ. These vacuum densities correspond to a gravitational source of the cosmological constant type for both subspaces of the branes. Using the generalized zeta function technique in combination with contour integral representations, the surface energies on the branes are presented in the form of the sum of single-brane and second-brane-induced parts. For the geometry of a single brane both regions, on the left and on the right of the brane, are considered. At the physical point the corresponding zeta functions contain pole and finite contributions. For an infinitely thin brane taking these regions together, in odd spatial dimensions the pole parts cancel and the total zeta function is finite. The renormalization procedure for the surface energies and the structure of the corresponding counterterms are discussed. The parts in the surface densities generated by the presence of the second brane are finite for all nonzero values of the interbrane separation and are investigated in various asymptotic regions of the parameters. In particular, it is shown that for large distances between the branes the induced surface densities give rise to an exponentially suppressed cosmological constant on the brane. The total energy of the vacuum including the bulk and boundary contributions is evaluated by the zeta function technique and the energy balance between separate parts is discussed

  1. Higher-Density Culture in Human Embryonic Stem Cells Results in DNA Damage and Genome Instability

    Directory of Open Access Journals (Sweden)

    Kurt Jacobs

    2016-03-01

    Full Text Available Human embryonic stem cells (hESC show great promise for clinical and research applications, but their well-known proneness to genomic instability hampers the development to their full potential. Here, we demonstrate that medium acidification linked to culture density is the main cause of DNA damage and genomic alterations in hESC grown on feeder layers, and this even in the short time span of a single passage. In line with this, we show that increasing the frequency of the medium refreshments minimizes the levels of DNA damage and genetic instability. Also, we show that cells cultured on laminin-521 do not present this increase in DNA damage when grown at high density, although the (long-term impact on their genomic stability remains to be elucidated. Our results explain the high levels of genome instability observed over the years by many laboratories worldwide, and show that the development of optimal culture conditions is key to solving this problem.

  2. 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...

  3. 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)

  4. 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

  5. Effect of higher implant density on curve correction in dystrophic thoracic scoliosis secondary to neurofibromatosis Type 1.

    Science.gov (United States)

    Li, Yang; Yuan, Xinxin; Sha, Shifu; Liu, Zhen; Zhu, Weiguo; Qiu, Yong; Wang, Bin; Yu, Yang; Zhu, Zezhang

    2017-10-01

    OBJECTIVE The aim of this study was to investigate how implant density affects radiographic results and clinical outcomes in patients with dystrophic scoliosis secondary to neurofibromatosis Type 1 (NF1). METHODS A total of 41 patients with dystrophic scoliosis secondary to NF1 who underwent 1-stage posterior correction between June 2011 and December 2013 were included. General information about patients was recorded, as were preoperative and postoperative scores from Scoliosis Research Society (SRS)-22 questionnaires. Pearson correlation analysis was used to analyze the associations among implant density, coronal Cobb angle correction rate and correction loss at last follow-up, change of sagittal curve, and apical vertebral translation. Patients were then divided into 2 groups: those with low-density and those with high-density implants. Independent-sample t-tests were used to compare demographic data, radiographic findings, and clinical outcomes before surgery and at last follow-up between the groups. RESULTS Significant correlations were found between the implant density and the coronal correction rate of the main curve (r = 0.505, p density and change of sagittal profile (p = 0.662) or apical vertebral translation (p = 0.062). The SRS-22 scores improved in the appearance, activity, and mental health domains within both groups, but there was no difference between the groups in any of the SRS-22 domains at final follow-up (p > 0.05 for all). CONCLUSIONS Although no significant differences between the high- and low-density groups were found in any of the SRS-22 domains at final follow-up, higher implant density was correlated with superior coronal correction and less postoperative correction loss in patients with dystrophic NF1-associated scoliosis.

  6. Higher critical current density achieved in Bi-2223 High-Tc superconductors

    Directory of Open Access Journals (Sweden)

    M.S. Shalaby

    2016-07-01

    Full Text Available Bi2Sr2Ca2Cu3Ox (Bi-2223 were prepared using a solid state reaction method at different sintering times and temperatures. Structural phase identifications have been done using X-Ray analysis and refinement by Reitveld method which proves the coexistence of Bi-2223 and Bi-2212 phases. The critical transition temperature Tc and critical current density Jc values were measured using superconducting quantum interference device magnetometer (SQUID and by the magneto-optics technique. A remarkable rapid decrease to the diamagnetic signal in the magnetization versus temperature M(T at 110 K and Jc around 1.2 × 107 A/m2 at 5 K are confirmed for the Bi-2223 compound.

  7. Effect of beam density and of higher harmonics on beam-plasma interaction

    International Nuclear Information System (INIS)

    Lacina, J.; Krlin, L.; Koerbel, S.

    1974-10-01

    The interaction in a cold electron beam-plasma system is investigated numerically in a density ratio region of nsub(B)/nsub(P) = 2 x 10 -3 to 2 x 10 -2 . The one-dimensional model of a collisionless plasma is used. The time development of the wave with maximal growing rate and its spatial harmonics is studied. The plasma effect is simulated by direct computation of plasma particle trajectories (this being different from the usual plasma simulation by means of a dielectric). The calculations show the following effects of the finite parameter (nsub(B)/nsub(P))sup(1/3): the ratio of the plasma energy to the electric field energy is increased, the damping character of the field and macroscopic amplitudes reveals, and the influence of the second harmonic is not negligible for nsub(B)/nsub(P) >= 10 -2 . (author)

  8. 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

  9. Spinor Green function in higher-dimensional cosmic string space-time in the presence of magnetic flux

    International Nuclear Information System (INIS)

    Spinelly, J.; Mello, E.R. Bezerra de

    2008-01-01

    In this paper we investigate the vacuum polarization effects associated with quantum fermionic charged fields in a generalized (d+1)-dimensional cosmic string space-times considering the presence of a magnetic flux along the string. In order to develop this analysis we calculate a general expression for the respective Green function, valid for several different values of d, which is expressed in terms of a bispinor associated with the square of the Dirac operator. Adopting this result, we explicitly calculate the renormalized vacuum expectation values of the energy-momentum tensors, (T A B ) Ren. , associated with massless fields. Moreover, for specific values of the parameters which codify the cosmic string and the fractional part of the ratio of the magnetic flux by the quantum one, we were able to present in closed forms the bispinor and the respective Green function for massive fields.

  10. 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

  11. Low bone density risk is higher in exercising women with multiple triad risk factors.

    Science.gov (United States)

    Gibbs, Jenna C; Nattiv, Aurelia; Barrack, Michelle T; Williams, Nancy I; Rauh, Mitchell J; Nichols, Jeanne F; De Souza, Mary Jane

    2014-01-01

    The cumulative effect of the female athlete triad (Triad) risk factors on the likelihood of low bone mineral density (BMD) in exercising women is unclear. This study aimed to determine the risk of low BMD in exercising women with multiple Triad risk factors. We retrospectively examined cross-sectional data from 437 exercising women (mean ± SD age of 18.0 ± 3.5 yr, weighed 57.5 ± 7.1 kg with 24.5% ± 6.1% body fat) obtained at baseline from 4 prospective cohort studies examining Triad risk factors. Questionnaires were completed to obtain information on demographic characteristics, self-reported eating attitudes/behaviors, menstrual function, sport/activity participation, and medication use. Height and body weight were measured. BMD was measured using dual energy x-ray absorptiometry. Low BMD was defined as z-scores of exercising women. Further research should be conducted to develop a user-friendly algorithm integrating these indicators of risk for low BMD in exercising women (particularly factors associated with low BMI/body weight, menstrual dysfunction, lean sport/activity participation, and elevated dietary restraint).

  12. The Oslo Health Study: Is bone mineral density higher in affluent areas?

    Science.gov (United States)

    Alver, Kari; Søgaard, Anne J; Falch, Jan A; Meyer, Haakon E

    2007-11-23

    Based on previously reported differences in fracture incidence in the socioeconomic less affluent Oslo East compared to the more privileged West, our aim was to study bone mineral density (BMD) in the same socioeconomic areas in Oslo. We also wanted to study whether possible associations were explained by socio-demographic factors, level of education or lifestyle factors. Distal forearm BMD was measured in random samples of the participants in The Oslo Health Study by single energy x-ray absorptiometry (SXA). 578 men and 702 women born in Norway in the age-groups 40/45, 60 and 75 years were included in the analyses. Socioeconomic regions, based on a social index dividing Oslo in two regions - East and West, were used. Age-adjusted mean BMD in women living in the less affluent Eastern region was 0.405 g/cm2 and significantly lower than in West where BMD was 0.419 g/cm2. Similarly, the odds ratio of low BMD (Z-score Oslo East compared to West. The same tendency, although not statistically significant, was also present in men. Multivariate analysis adjusted for education, marital status, body mass index, physical inactivity, use of alcohol and smoking, and in women also use of post-menopausal hormone therapy and early onset of menopause, did hardly change the association. Additional adjustments for employment status, disability pension and physical activity at work for those below the age of retirement, gave similar results. We found differences in BMD in women between different socioeconomic regions in Oslo that correspond to previously found differences in fracture rates. The association in men was not statistically significant. The differences were not explained by socio-demographic factors, level of education or lifestyle factors.

  13. The Oslo Health Study: Is bone mineral density higher in affluent areas?

    Directory of Open Access Journals (Sweden)

    Søgaard Anne J

    2007-11-01

    Full Text Available Abstract Background Based on previously reported differences in fracture incidence in the socioeconomic less affluent Oslo East compared to the more privileged West, our aim was to study bone mineral density (BMD in the same socioeconomic areas in Oslo. We also wanted to study whether possible associations were explained by socio-demographic factors, level of education or lifestyle factors. Methods Distal forearm BMD was measured in random samples of the participants in The Oslo Health Study by single energy x-ray absorptiometry (SXA. 578 men and 702 women born in Norway in the age-groups 40/45, 60 and 75 years were included in the analyses. Socioeconomic regions, based on a social index dividing Oslo in two regions – East and West, were used. Results Age-adjusted mean BMD in women living in the less affluent Eastern region was 0.405 g/cm2 and significantly lower than in West where BMD was 0.419 g/cm2. Similarly, the odds ratio of low BMD (Z-score ≤ -1 was 1.87 (95% CI: 1.22–2.87 in women in Oslo East compared to West. The same tendency, although not statistically significant, was also present in men. Multivariate analysis adjusted for education, marital status, body mass index, physical inactivity, use of alcohol and smoking, and in women also use of post-menopausal hormone therapy and early onset of menopause, did hardly change the association. Additional adjustments for employment status, disability pension and physical activity at work for those below the age of retirement, gave similar results. Conclusion We found differences in BMD in women between different socioeconomic regions in Oslo that correspond to previously found differences in fracture rates. The association in men was not statistically significant. The differences were not explained by socio-demographic factors, level of education or lifestyle factors.

  14. Photonic Integrated Circuits for Cost-Effective, High Port Density, and Higher Capacity Optical Communications Systems

    Science.gov (United States)

    Chiappa, Pierangelo

    Bandwidth-hungry services, such as higher speed Internet, voice over IP (VoIP), and IPTV, allow people to exchange and store huge amounts of data among worldwide locations. In the age of global communications, domestic users, companies, and organizations around the world generate new contents making bandwidth needs grow exponentially, along with the need for new services. These bandwidth and connectivity demands represent a concern for operators who require innovative technologies to be ready for scaling. To respond efficiently to these demands, Alcatel-Lucent is fast moving toward photonic integration circuits technologies as the key to address best performances at the lowest "bit per second" cost. This article describes Alcatel-Lucent's contribution in strategic directions or achievements, as well as possible new developments.

  15. The Case for Higher Computational Density in the Memory-Bound FDTD Method within Multicore Environments

    Directory of Open Access Journals (Sweden)

    Mohammed F. Hadi

    2012-01-01

    Full Text Available It is argued here that more accurate though more compute-intensive alternate algorithms to certain computational methods which are deemed too inefficient and wasteful when implemented within serial codes can be more efficient and cost-effective when implemented in parallel codes designed to run on today's multicore and many-core environments. This argument is most germane to methods that involve large data sets with relatively limited computational density—in other words, algorithms with small ratios of floating point operations to memory accesses. The examples chosen here to support this argument represent a variety of high-order finite-difference time-domain algorithms. It will be demonstrated that a three- to eightfold increase in floating-point operations due to higher-order finite-differences will translate to only two- to threefold increases in actual run times using either graphical or central processing units of today. It is hoped that this argument will convince researchers to revisit certain numerical techniques that have long been shelved and reevaluate them for multicore usability.

  16. Maternal effects on male weaponry: female dung beetles produce major sons with longer horns when they perceive higher population density

    Directory of Open Access Journals (Sweden)

    Buzatto Bruno A

    2012-07-01

    Full Text Available Abstract Background Maternal effects are environmental influences on the phenotype of one individual that are due to the expression of genes in its mother, and are expected to evolve whenever females are better capable of assessing the environmental conditions that their offspring will experience than the offspring themselves. In the dung beetle Onthophagus taurus, conditional male dimorphism is associated with alternative reproductive tactics: majors fight and guard females whereas minors sneak copulations. Furthermore, variation in dung beetle population density has different fitness consequences for each male morph, and theory predicts that higher population density might select for a higher frequency of minors and/or greater expenditure on weaponry in majors. Because adult dung beetles provide offspring with all the nutritional resources for their development, maternal effects strongly influence male phenotype. Results Here we tested whether female O. taurus are capable of perceiving population density, and responding by changing the phenotype of their offspring. We found that mothers who were reared with other conspecifics in their pre-mating period produced major offspring that had longer horns across a wider range of body sizes than the major offspring of females that were reared in isolation in their pre-mating period. Moreover, our results indicate that this maternal effect on male weaponry does not operate through the amount of dung provided by females to their offspring, but is rather transmitted through egg or brood mass composition. Finally, although theory predicts that females experiencing higher density might produce more minor males, we found no support for this, rather the best fitting models were equivocal as to whether fewer or the same proportions of minors were produced. Conclusions Our study describes a new type of maternal effect in dung beetles, which probably allows females to respond to population density adaptively

  17. 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.

  18. Higher density of serotonin-1A receptors in the hippocampus and cerebral cortex of alcohol-preferring P rats

    International Nuclear Information System (INIS)

    Wong, D.T.; Threlkeld, P.G.; Lumeng, L.; Li, Ting-Kai

    1990-01-01

    Saturable [ 3 H]-80HDPAT binding to 5HT-1A receptors in membranes prepared from hippocampus and frontal cerebral cortex of alcohol-preferring (P) rats and of alcohol-nonpreferring (NP) rats has been compared. The B max values or densities of recognition sites for 5HT-1A receptors in both brain areas of the P rats are 38 and 44 percent lower in the P rats than in the NP rats. The corresponding K D values are 38 and 44 percent lower in the P rats than in the NP rats, indicating higher affinities of the recognition sites for the 5HT-1A receptors in hippocampus and cerebral cortex of the P rats. These findings indicate either an enrichment of 5HT-1A receptor density during selective breeding for alcohol preference or an upregulation of 5HT-1A receptors of 5HT found in these brain areas of P rats as compared with the NP rats

  19. Safeguarding subcriticality during loading and shuffling operations in the higher density of the RSG-GAS's silicide core

    International Nuclear Information System (INIS)

    Sembiring, T.M.; Kuntoro, I.

    2003-01-01

    The core conversion program of the RSG-GAS reactor is to convert the all-oxide to all-silicide core. The silicide equilibrium core with fuel meat density of 3.55 gU cm -3 is an optimal core for RSG-GAS reactor and it can significantly increase the operation cycle length from 25 to 32 full power days. Nevertheless, the subcriticality of the shutdown core and the shutdown margin are lower than of the oxide core. Therefore, the deviation of subcriticality condition in the higher silicide core caused by the fuel loading and shuffling error should be reanalysed. The objective of this work is to analyse the sufficiency of the subcriticality condition of the shutdown core to face the worst condition caused by an error during loading and shuffling operations. The calculations were carried out using the 2-dimensional multigroup neutron diffusion code of Batan-FUEL. In the fuel handling error, the calculated results showed that the subcriticality condition of the shutdown higher density silicide equilibrium core of RSG-GAS can be maintained. Therefore, all fuel management steps are fixed in the present reactor operation manual can be applied in the higher silicide equilibrium core of RSG-GAS reactor. (author)

  20. 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

  1. 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.

  2. 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

  3. 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

  4. Gamow-Jordan vectors and non-reducible density operators from higher-order S-matrix poles

    International Nuclear Information System (INIS)

    Bohm, A.; Loewe, M.; Maxson, S.; Patuleanu, P.; Puentmann, C.; Gadella, M.

    1997-01-01

    In analogy to Gamow vectors that are obtained from first-order resonance poles of the S-matrix, one can also define higher-order Gamow vectors which are derived from higher-order poles of the S-matrix. An S-matrix pole of r-th order at z R =E R -iΓ/2 leads to r generalized eigenvectors of order k=0,1,hor-ellipsis,r-1, which are also Jordan vectors of degree (k+1) with generalized eigenvalue (E R -iΓ/2). The Gamow-Jordan vectors are elements of a generalized complex eigenvector expansion, whose form suggests the definition of a state operator (density matrix) for the microphysical decaying state of this higher-order pole. This microphysical state is a mixture of non-reducible components. In spite of the fact that the k-th order Gamow-Jordan vectors has the polynomial time-dependence which one always associates with higher-order poles, the microphysical state obeys a purely exponential decay law. copyright 1997 American Institute of Physics

  5. 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.

  6. 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.

  7. 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.

  8. 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)

  9. 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

  10. 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

  11. Argyrophil cell density in the oxyntic mucosa is higher in female than in male morbidly obese patients

    International Nuclear Information System (INIS)

    Maksud, F.A.N.; Kakehasi, A.M.; Barbosa, A.J.A.

    2013-01-01

    Obesity is a multifactorial disorder often associated with many important diseases such as diabetes, hypertension and other metabolic syndrome conditions. Argyrophil cells represent almost the total population of endocrine cells of the human gastric mucosa and some reports have described changes of specific types of these cells in patients with obesity and metabolic syndrome. The present study was designed to evaluate the global population of argyrophil cells of the gastric mucosa of morbidly obese and dyspeptic non-obese patients. Gastric biopsies of antropyloric and oxyntic mucosa were obtained from 50 morbidly obese patients (BMI >40) and 50 non-obese patients (17 dyspeptic overweight and 33 lean individuals) and processed for histology and Grimelius staining for argyrophil cell demonstration. Argyrophil cell density in the oxyntic mucosa of morbidly obese patients was higher in female (238.68 ± 83.71 cells/mm 2 ) than in male patients (179.31 ± 85.96 cells/mm 2 ) and also higher in female (214.20 ± 50.38 cells/mm 2 ) than in male (141.90 ± 61.22 cells/mm 2 ) morbidly obese patients with metabolic syndrome (P = 0.01 and P = 0.02, respectively). In antropyloric mucosa, the main difference in argyrophil cell density was observed between female morbidly obese patients with (167.00 ± 69.30 cells/mm 2 ) and without (234.00 ± 69.54 cells/mm 2 ) metabolic syndrome (P = 0.001). In conclusion, the present results show that the number of gastric argyrophil cells could be under gender influence in patients with morbid obesity. In addition, gastric argyrophil cells seem to behave differently among female morbidly obese patients with and without metabolic syndrome

  12. Argyrophil cell density in the oxyntic mucosa is higher in female than in male morbidly obese patients

    Energy Technology Data Exchange (ETDEWEB)

    Maksud, F.A.N. [Laboratório de Patologia Digestiva e Neuroendócrina, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Faculdade de Medicina, Universidade Federal de Ouro Preto, Ouro Preto, MG (Brazil); Kakehasi, A.M. [Laboratório de Patologia Digestiva e Neuroendócrina, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Barbosa, A.J.A. [Laboratório de Patologia Digestiva e Neuroendócrina, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Instituto Alfa de Gastroenterologia, Belo Horizonte, MG (Brazil)

    2013-04-05

    Obesity is a multifactorial disorder often associated with many important diseases such as diabetes, hypertension and other metabolic syndrome conditions. Argyrophil cells represent almost the total population of endocrine cells of the human gastric mucosa and some reports have described changes of specific types of these cells in patients with obesity and metabolic syndrome. The present study was designed to evaluate the global population of argyrophil cells of the gastric mucosa of morbidly obese and dyspeptic non-obese patients. Gastric biopsies of antropyloric and oxyntic mucosa were obtained from 50 morbidly obese patients (BMI >40) and 50 non-obese patients (17 dyspeptic overweight and 33 lean individuals) and processed for histology and Grimelius staining for argyrophil cell demonstration. Argyrophil cell density in the oxyntic mucosa of morbidly obese patients was higher in female (238.68 ± 83.71 cells/mm{sup 2}) than in male patients (179.31 ± 85.96 cells/mm{sup 2}) and also higher in female (214.20 ± 50.38 cells/mm{sup 2}) than in male (141.90 ± 61.22 cells/mm{sup 2}) morbidly obese patients with metabolic syndrome (P = 0.01 and P = 0.02, respectively). In antropyloric mucosa, the main difference in argyrophil cell density was observed between female morbidly obese patients with (167.00 ± 69.30 cells/mm{sup 2}) and without (234.00 ± 69.54 cells/mm{sup 2}) metabolic syndrome (P = 0.001). In conclusion, the present results show that the number of gastric argyrophil cells could be under gender influence in patients with morbid obesity. In addition, gastric argyrophil cells seem to behave differently among female morbidly obese patients with and without metabolic syndrome.

  13. 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

  14. 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

  15. Evidence for higher tropical storm risks in Haiti due to increasing population density in hazard prone urban areas

    International Nuclear Information System (INIS)

    Klose, Christian D

    2011-01-01

    Since the 18th century, the Republic of Haiti has experienced numerous tropical cyclones. In 2011, the United Nations Global Assessment Report on Disaster Risk Reduction outlined that the worldwide physical exposure to natural hazards, which includes tropical storms and hurricanes in Haiti, increased by 192 per cent between 1970 and 2010. Now, it can be hypothesized that the increased physical exposure to cyclones that made landfall in Haiti has affected the country's development path. This study shows that tropical storm risks in Haiti increased due to more physical exposure of the population in urban areas rather than a higher cyclone frequency in the proximity of Hispaniola island. In fact, the population density accelerated since the second half of the 20th century in regions where historically more storms made landfall, such as in the departments Ouest, Artibonite, Nord and Nord-Ouest including Haiti's four largest cities: Port-au-Prince, Gonaïves, Cap-Haïtien and Port-de-Paix. Thus, urbanization in and migration into storm hazard prone areas could be considered as one of the major driving forces of Haiti's fragility.

  16. Higher media multi-tasking activity is associated with smaller gray-matter density in the anterior cingulate cortex.

    Directory of Open Access Journals (Sweden)

    Kep Kee Loh

    Full Text Available Media multitasking, or the concurrent consumption of multiple media forms, is increasingly prevalent in today's society and has been associated with negative psychosocial and cognitive impacts. Individuals who engage in heavier media-multitasking are found to perform worse on cognitive control tasks and exhibit more socio-emotional difficulties. However, the neural processes associated with media multi-tasking remain unexplored. The present study investigated relationships between media multitasking activity and brain structure. Research has demonstrated that brain structure can be altered upon prolonged exposure to novel environments and experience. Thus, we expected differential engagements in media multitasking to correlate with brain structure variability. This was confirmed via Voxel-Based Morphometry (VBM analyses: Individuals with higher Media Multitasking Index (MMI scores had smaller gray matter density in the anterior cingulate cortex (ACC. Functional connectivity between this ACC region and the precuneus was negatively associated with MMI. Our findings suggest a possible structural correlate for the observed decreased cognitive control performance and socio-emotional regulation in heavy media-multitaskers. While the cross-sectional nature of our study does not allow us to specify the direction of causality, our results brought to light novel associations between individual media multitasking behaviors and ACC structure differences.

  17. Constitutive melanin density is associated with higher 25-hydroxyvitamin D and potentially total body BMD in older Caucasian adults via increased sun tolerance and exposure.

    Science.gov (United States)

    Thompson, M J W; Jones, G; Aitken, D A

    2018-06-01

    Greater skin pigmentation reduces dose equivalent cutaneous vitamin D3 production, potentially impacting lifetime vitamin D status and fracture risk. We show that melanin density was positively associated with 25-hydroxyvitamin D and total body bone mineral density. These relationships were partially explained by greater sun exposure due to more permissive skin phenotype. Higher cutaneous melanin reduces vitamin D3 production. This may impact lifetime vitamin D status and increase fracture risk. This study aimed to describe the relationship between spectrophotometrically determined constitutive melanin density, osteoporotic risk factors and potential intermediaries in a cohort of exclusively older Caucasian adults. One thousand seventy-two community-dwelling adults aged 50-80 years had constitutive melanin density quantified using spectrophotometry. Sun exposure, skin phenotype, non-melanoma skin cancer (NMSC) prevalence and smoking status were assessed by questionnaire. Bone mineral density (BMD), falls risk, physical activity and 25-hydroxyvitamin D were measured using DXA, the short form Physiological Profile Assessment, pedometer and radioimmunoassay, respectively. Higher melanin density was independently associated with greater ability to tan (RR = 1.27, p density and sun exposure (RR = 1.05-1.11, p density (β = 1.71-2.05, p = 0.001). The association between melanin density and total body BMD (β = 0.007, p = 0.04) became non-significant after adjustment for 25-hydroxyvitamin D. There was no association between melanin density and physical activity, falls risk or BMD at other sites. Our data support a model of higher constitutive melanin density underpinning a less photosensitive skin phenotype, permitting greater sun exposure with fewer sequelae and yielding higher 25-hydroxyvitamin D and, potentially, total body BMD.

  18. 光温条件和pH对浮萍生长及磷吸收的影响%Effect of Photon Flux Density and pH on Growth Ability and Phosphorus Removal Efficiency of Two Duckweed Species

    Institute of Scientific and Technical Information of China (English)

    蔡树美; 张震; 辛静; 周雄飞; 钱晓晴

    2011-01-01

    试验以长江三角洲地区常见的稀脉浮萍和少根紫萍为研究对象.在Hoagland's E-Medium营养液进行实验室模拟培养的基础上,研究了光温条件以及pH对两种浮萍生长和磷去除能力的影响.结果表明,在1500-6000 1x光照强度范围内,光照越强,两种浮萍的生长和磷去除能力越强;在10-35℃温度范围内,两种浮萍生长和磷去除的最佳气温为25℃,高温和低温对浮萍的生长都有一定的抑制作用,且低温的抑制作用更明显;在pH5~9范围内,稀脉浮萍和少根紫萍生长和磷去除的最佳pH值分别为6.0和5.0,越偏离最佳生长pH值,pH对浮萍生长和磷去除的抑制效果越明显.%Effect of photon flux density,temperature and pH on growth ability and phosphorus removal efficiency of Lemna aequinoctialis and Spirodela oligorrhiza, which are common species in Yangtze Delta region,was assessed with laboratory artificial culture experiments using Hoagland's E-Medium. Results indicated that the stronger photon flux density was,higher growth ability and phosphorus removal efficiency of duckweeds would become in photon flux density range of 1 500~6 000tx.The optimal temperature condition for duckweeds growth and phosphorus removal was 25 ℃ among temperature from 10 ℃ to 35 ℃. Either low or high temperature would lead to reduce the growth rate of duckweed,and restrain effect of low temperature was more significant. Among pH fora 5 to 9,the optimal pH condition for Lemna aequinoctialis and Spirodela oligorrhiza was pH 6.0 and 5.0 respectively. Deviation from the optimal pH value caused a distinct restrain of both growth ability and phosphorus removal efficiency.

  19. Quantitative computed tomography of lung parenchyma in patients with emphysema: analysis of higher-density lung regions

    Science.gov (United States)

    Lederman, Dror; Leader, Joseph K.; Zheng, Bin; Sciurba, Frank C.; Tan, Jun; Gur, David

    2011-03-01

    Quantitative computed tomography (CT) has been widely used to detect and evaluate the presence (or absence) of emphysema applying the density masks at specific thresholds, e.g., -910 or -950 Hounsfield Unit (HU). However, it has also been observed that subjects with similar density-mask based emphysema scores could have varying lung function, possibly indicating differences of disease severity. To assess this possible discrepancy, we investigated whether density distribution of "viable" lung parenchyma regions with pixel values > -910 HU correlates with lung function. A dataset of 38 subjects, who underwent both pulmonary function testing and CT examinations in a COPD SCCOR study, was assembled. After the lung regions depicted on CT images were automatically segmented by a computerized scheme, we systematically divided the lung parenchyma into different density groups (bins) and computed a number of statistical features (i.e., mean, standard deviation (STD), skewness of the pixel value distributions) in these density bins. We then analyzed the correlations between each feature and lung function. The correlation between diffusion lung capacity (DLCO) and STD of pixel values in the bin of -910HU lung parenchyma and lung function, which indicates that similar to the conventional density mask method, the pixel value distribution features in "viable" lung parenchyma areas may also provide clinically useful information to improve assessments of lung disease severity as measured by lung functional tests.

  20. High heat flux cooling for accelerator targets

    International Nuclear Information System (INIS)

    Silverman, I.; Nagler, A.

    2002-01-01

    Accelerator targets, both for radioisotope production and for high neutron flux sources generate very high thermal power in the target material which absorbs the particles beam. Generally, the geometric size of the targets is very small and the power density is high. The design of these targets requires dealing with very high heat fluxes and very efficient heat removal techniques in order to preserve the integrity of the target. Normal heat fluxes from these targets are in the order of 1 kw/cm 2 and may reach levels of an order of magnitude higher

  1. Higher gamma-aminobutyric acid neuron density in the white matter of orbital frontal cortex in schizophrenia.

    Science.gov (United States)

    Joshi, Dipesh; Fung, Samantha J; Rothwell, Alice; Weickert, Cynthia Shannon

    2012-11-01

    In the orbitofrontal cortex (OFC), reduced gray matter volume and reduced glutamic acid decarboxylase 67kDa isoform (GAD67) messenger (m)RNA are found in schizophrenia; however, how these alterations relate to developmental pathology of interneurons is unclear. The present study therefore aimed to determine if increased interstitial white matter neuron (IWMN) density exists in the OFC; whether gamma-aminobutyric acid (GABA)ergic neuron density in OFC white matter was altered; and how IWMN density may be related to an early-expressed inhibitory neuron marker, Dlx1, in OFC gray matter in schizophrenia. IWMN densities were determined (38 schizophrenia and 38 control subjects) for neuronal nuclear antigen (NeuN+) and 65/67 kDa isoform of glutamic acid decarboxylase immunopositive (GAD65/67+) neurons. In situ hybridization was performed to determine Dlx1 and GAD67 mRNA expression in the OFC gray matter. NeuN and GAD65/67 immunopositive cell density was significantly increased in the superficial white matter in schizophrenia. Gray matter Dlx1 and GAD67 mRNA expression were reduced in schizophrenia. Dlx1 mRNA levels were negatively correlated with GAD65/67 IWMN density. Our study provides evidence that pathology of IWMNs in schizophrenia includes GABAergic interneurons and that increased IWMN density may be related to GABAergic deficits in the overlying gray matter. These findings provide evidence at the cellular level that the OFC is a site of pathology in schizophrenia and support the hypothesis that inappropriate migration of cortical inhibitory interneurons occurs in schizophrenia. Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  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. Controlling Cu–Sn mixing so as to enable higher critical current densities in RRP® Nb3Sn wires

    Science.gov (United States)

    Sanabria, Charlie; Field, Michael; Lee, Peter J.; Miao, Hanping; Parrell, Jeff; Larbalestier, David C.

    2018-06-01

    Dipole magnets for the proposed Future Circular Collider (FCC) demand specifications significantly beyond the limits of all existing Nb3Sn wires, in particular a critical current density (J c) of more than 1500 A mm‑2 at 16 T and 4.2 K with an effective filament diameter (D eff) of less than 20 μm. The restacked-rod-process (RRP®) is the technology closest to meeting these demands, with a J c (16 T) of up to 1400 A mm‑2, residual resistivity ratio > 100, for a sub-element size D s of 58 μm (which in RRP® wires is essentially the same as D eff). An important present limitation of RRP® is that reducing the sub-element size degrades J c to as low as 900 A mm‑2 at 16 T for D s = 35 μm. To gain an understanding of the sources of this J c degradation, we have made a detailed study of the phase evolution during the Cu–Sn ‘mixing’ stages of the wire heat treatment that occur prior to Nb3Sn formation. Using extensive microstructural quantification, we have identified the critical role that the Sn–Nb–Cu ternary phase (Nausite) can play. The Nausite forms as a well-defined ring between the Sn source and the Cu/Nb filament pack, and acts as an osmotic membrane in the 300 °C–400 °C range—greatly inhibiting Sn diffusion into the Cu/Nb filament pack while supporting a strong Cu counter-diffusion from the filament pack into the Sn core. This converts the Sn core into a mixture of the low melting point (408 °C) η phase (Cu6Sn5) and the more desirable ε phase (Cu3Sn), which decomposes at 676 °C. After the mixing stages, when heated above 408 °C towards the Nb3Sn reaction, any residual η liquefies to form additional irregular Nausite on the inside of the membrane. All Nausite decomposes into NbSn2 on further heating, and ultimately transforms into coarse-grain (and often disconnected) Nb3Sn which has little contribution to current transport. Understanding this critical Nausite reaction pathway has allowed us to simplify the mixing heat treatment to

  6. Higher densities of fast-food and full-service restaurants are not associated with obesity prevalence.

    Science.gov (United States)

    Mazidi, Mohsen; Speakman, John R

    2017-08-01

    Background: The obesity epidemic in the United States has been mirrored by an increase in calories consumed outside of the home and by expansions in the numbers of, and portion sizes at, both fast-food restaurants (FFRs) and full-service restaurants (FSRs), leading some to blame the epidemic on the restaurant industry. If this were indeed true, one would predict that greater per capita densities of FFRs and FSRs would lead to greater obesity prevalence. Objective: We evaluated the population-level association between both FSRs and FFRs and the prevalence of obesity and calculated the proportion of calories consumed in these establishments. Design: In this ecological cross-sectional study, we used county-level data (aggregate-level data) for obesity prevalence across the mainland United States in 2012 and matched these data to county-level per capita densities of FFRs and FSRs in the same year. Multiple linear regression was used to determine the relation between the prevalence of obesity and the densities of FFRs and FSRs after adjustment for confounding factors. Results: Contrary to expectations, obesity prevalence was highly significantly negatively related to the densities of both FFRs and FSRs (combined-effect R 2 = 0.195). This was principally because greater numbers of both FFRs and FSRs were located in areas in which individuals were on average wealthier and more educated. When we normalized for these factors (and additional socioeconomic variables), the associations between restaurant densities and obesity effectively disappeared (pooled R 2 = 0.008). Our calculations showed that the percentage of total calories consumed in FFRs and FSRs is a mean of only 15.9% of the total intake (maximum: 22.6%). Conclusions: Variations in the densities of FFRs and FSRs are not linked to the prevalence of obesity in the United States, and food consumed in these establishments is responsible for <20% of total energy intake. This finding has implications for policy

  7. 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

  8. 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

  9. 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.

  10. Exact Jacobians of Roe-type flux difference splitting of the equations of radiation hydrodynamics (and Euler equations) for use in time-implicit higher-order Godunov schemes

    International Nuclear Information System (INIS)

    Balsara, D.S.

    1999-01-01

    In this paper we analyze some of the numerical issues that are involved in making time-implicit higher-order Godunov schemes for the equations of radiation hydrodynamics (and the Euler or Navier-Stokes equations). This is done primarily with the intent of incorporating such methods in the author's RIEMANN code. After examining the issues it is shown that the construction of a time-implicit higher-order Godunov scheme for radiation hydrodynamics would be benefited by our ability to evaluate exact Jacobians of the numerical flux that is based on Roe-type flux difference splitting. In this paper we show that this can be done analytically in a form that is suitable for efficient computational implementation. It is also shown that when multiple fluid species are used or when multiple radiation frequencies are used the computational cost in the evaluation of the exact Jacobians scales linearly with the number of fluid species or the number of radiation frequencies. Connections are made to other types of numerical fluxes, especially those based on flux difference splittings. It is shown that the evaluation of the exact Jacobian for such numerical fluxes is also benefited by the present strategy and the results given here. It is, however, pointed out that time-implicit schemes that are based on the evaluation of the exact Jacobians for flux difference splittings using the methods developed here are both computationally more efficient and numerically more stable than corresponding time-implicit schemes that are based on the evaluation of the exact or approximate Jacobians for flux vector splittings. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  11. Enhancement of the critical current density and flux pinning of MgB2 superconductor by nanoparticle SiC doping

    Science.gov (United States)

    Dou, S. X.; Soltanian, S.; Horvat, J.; Wang, X. L.; Zhou, S. H.; Ionescu, M.; Liu, H. K.; Munroe, P.; Tomsic, M.

    2002-10-01

    Doping of MgB2 by nano-SiC and its potential for the improvement of flux pinning were studied for MgB2-x)(SiCx/2 with x=0, 0.2, and 0.3 and for 10 wt % nano-SiC-doped MgB2 samples. Cosubstitution of B by Si and C counterbalanced the effects of single-element doping, decreasing Tc by only 1.5 K, introducing intragrain pinning centers effective at high fields and temperatures, and significantly enhancing Jc and Hirr. Compared to the undoped sample, Jc for the 10 wt % doped sample increased by a factor of 32 at 5 K and 8 T, 42 at 20 K and 5 T, and 14 at 30 K and 2 T. At 20 K and 2 T, the Jc for the doped sample was 2.4 x105 A/cm2, which is comparable to Jc values for the best Ag/Bi-2223 tapes. At 20 K and 4 T, Jc was twice as high as for the best MgB2 thin films and an order of magnitude higher than for the best Fe/MgB2 tapes. The magnetic Jc is consistent with the transport Jc which remains at 20 000 A/cm2 even at 10 T and 5 K for the doped sample, an order of magnitude higher than the undoped one. Because of such high performance, it is anticipated that the future MgB2 conductors will be made using a formula of MgBxSiyCz instead of pure MgB2.

  12. Greater milk intake is associated with lower bone turnover, higher bone density, and higher bone microarchitecture index in a population of elderly Japanese men with relatively low dietary calcium intake: Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) Study.

    Science.gov (United States)

    Sato, Y; Iki, M; Fujita, Y; Tamaki, J; Kouda, K; Yura, A; Moon, J-S; Winzenrieth, R; Iwaki, H; Ishizuka, R; Amano, N; Tomioka, K; Okamoto, N; Kurumatani, N

    2015-05-01

    The effects of milk intake on bone health are not clear in elderly Asian men with low dietary calcium intake. This study showed that greater milk intake is associated with lower bone turnover, higher bone density, and higher bone microarchitecture index in community-dwelling elderly Japanese men. The consumption of milk or dairy products is widely recommended for maintaining bone health regardless of gender or age. However, little evidence exists on the beneficial effects of milk intake on bone health in elderly Japanese men characterized with relatively low dietary calcium intake. Here we examined whether or not greater milk intake was associated with lower bone turnover, higher bone density, and stronger bone microarchitecture in community-dwelling elderly Japanese men. Interviews were conducted to obtain information on medical history and lifestyle, including the amount of habitual milk intake, nutrient intake calculations based on a 1-week food diary, and measurements of areal bone mineral density (aBMD) at the lumbar spine (LS), total hip (TH), and femoral neck (FN) by dual-energy x-ray absorptiometry (DXA), trabecular bone score (TBS) using DXA images at LS, and biochemical markers of bone turnover in sera. Participants with a history of diseases or medications that affect bone metabolism, or with missing data, were excluded from the analysis. The median intake of milk in the 1479 participants (mean age, 73.0 ± 5.1 years) was one glass of milk per day. Bone turnover markers showed a decreasing trend (p turnover, higher aBMD, and higher TBS in community-dwelling elderly Japanese men.

  13. [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

  14. Milk and yogurt consumption are linked with higher bone mineral density but not with hip fracture: the Framingham Offspring Study.

    Science.gov (United States)

    Sahni, Shivani; Tucker, Katherine L; Kiel, Douglas P; Quach, Lien; Casey, Virginia A; Hannan, Marian T

    2013-01-01

    Dairy foods are a complex source of essential nutrients. In this study, fluid dairy intake, specifically milk, and yogurt intakes were associated with hip but not spine bone mineral density (BMD), while cream may adversely influence BMD, suggesting that not all dairy products are equally beneficial for the skeleton. This study seeks to examine associations of milk, yogurt, cheese, cream, most dairy (total dairy without cream), and fluid dairy (milk + yogurt) with BMD at femoral neck (FN), trochanter (TR), and spine, and with incident hip fracture over 12-year follow-up in the Framingham Offspring Study. Three thousand two hundred twelve participants completed a food frequency questionnaire (1991–1995 or 1995–1998) and were followed for hip fracture until 2007 [corrected]. Two thousand five hundred and six participants had DXA BMD (1996-2001). Linear regression was used to estimate adjusted mean BMD while Cox-proportional hazards regression was used to estimate adjusted hazard ratios (HR) for hip fracture risk. Final models simultaneously included dairy foods adjusting for each other. Mean baseline age was 55 (±1.6) years, range 26-85. Most dairy intake was positively associated with hip and spine BMD. Intake of fluid dairy and milk was related with hip but not spine BMD. Yogurt intake was associated with TR-BMD alone. Cheese and cream intakes were not associated with BMD. In final models, yogurt intake remained positively associated with TR-BMD, while cream tended to be negatively associated with FN-BMD. Yogurt intake showed a weak protective trend for hip fracture [HR(95%CI), ≤4 serv/week, 0.46 (0.21-1.03) vs. >4 serv/week, 0.43 (0.06-3.27)]. No other dairy groups showed a significant association (HRs range, 0.53-1.47) with limited power (n, fractures = 43). Milk and yogurt intakes were associated with hip but not spine BMD, while cream may adversely influence BMD. Thus, not all dairy products are equally beneficial for the skeleton. Suggestive fracture

  15. Modelling drug flux through microporated skin.

    Science.gov (United States)

    Rzhevskiy, Alexey S; Guy, Richard H; Anissimov, Yuri G

    2016-11-10

    A simple mathematical equation has been developed to predict drug flux through microporated skin. The theoretical model is based on an approach applied previously to water evaporation through leaf stomata. Pore density, pore radius and drug molecular weight are key model parameters. The predictions of the model were compared with results derived from a simple, intuitive method using porated area alone to estimate the flux enhancement. It is shown that the new approach predicts significantly higher fluxes than the intuitive analysis, with transport being proportional to the total pore perimeter rather than area as intuitively anticipated. Predicted fluxes were in good general agreement with experimental data on drug delivery from the literature, and were quantitatively closer to the measured values than those derived from the intuitive, area-based approach. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Testing joint inversion techniques of gravity data and cosmic ray muon flux at a well-characterized site for use in the detection of subsurface density structures beneath volcanoes.

    Science.gov (United States)

    Cosburn, K.; Roy, M.; Rowe, C. A.; Guardincerri, E.

    2017-12-01

    Obtaining accurate static and time-dependent shallow subsurface density structure beneath volcanic, hydrogeologic, and tectonic targets can help illuminate active processes of fluid flow and magma transport. A limitation of using surface gravity measurements for such imaging is that these observations are vastly underdetermined and non-unique. In order to hone in on a more accurate solution, other data sets are needed to provide constraints, typically seismic or borehole observations. The spatial resolution of these techniques, however, is relatively poor, and a novel solution to this problem in recent years has been to use attenuation of the cosmic ray muon flux, which provides an independent constraint on density. In this study we present a joint inversion of gravity and cosmic ray muon flux observations to infer the density structure of a target rock volume at a well-characterized site near Los Alamos, New Mexico, USA. We investigate the shallow structure of a mesa formed by the Quaternary ash-flow tuffs on the Pajarito Plateau, flanking the Jemez volcano in New Mexico. Gravity measurements were made using a Lacoste and Romberg D meter on the surface of the mesa and inside a tunnel beneath the mesa. Muon flux measurements were also made at the mesa surface and at various points within the same tunnel using a muon detector having an acceptance region of 45 degrees from the vertical and a track resolution of several milliradians. We expect the combination of muon and gravity data to provide us with enhanced resolution as well as the ability to sense deeper structures in our region of interest. We use Bayesian joint inversion techniques on the gravity-muon dataset to test these ideas, building upon previous work using gravity inversion alone to resolve density structure in our study area. Both the regional geology and geometry of our study area is well-known and we assess the inferred density structure from our gravity-muon joint inversion within this known

  17. Flux distribution in single phase, Si-Fe, wound transformer cores

    International Nuclear Information System (INIS)

    Loizos, George; Kefalas, Themistoklis; Kladas, Antonios; Souflaris, Thanassis; Paparigas, Dimitris

    2008-01-01

    This paper shows experimental results of longitudinal flux density and its harmonics at the limb, the yoke and the corner as well as normal flux in the step lap joint of a single phase, Si-Fe, wound transformer core. Results show that the flux density as well as the harmonics content is higher in the inner (window) side of the core and reduces gradually towards the outer side. Variations of flux density distribution between the limb and the corner or the yoke of the core were observed. A full record of normal flux around the step lap region of the model core was also obtained. Longitudinal and normal flux findings will enable the development of more accurate numerical models that describe the magnetic behavior of magnetic cores

  18. Enhancement of Critical Current Density and Flux Pinning in Acetone and La2O3 Codoped MgB2 Tapes

    International Nuclear Information System (INIS)

    Gao Zhao-Shun; Ma Yan-Wei; Wang Dong-Liang; Zhang Xian-Ping; Awaji Satoshi; Watanabe Kazuo

    2010-01-01

    MgB 2 tape samples with simultaneous additions of acetone and La 2 O 3 were prepared by an in-situ processed powder-in-tube method. Compared to the pure and single doped tapes, both transport J c and fluxing pinning are greatly improved by acetone and La 2 O 3 codoping. Acetone supplies carbon into the MgB 2 crystal lattice and increases the upper critical field, while the La 2 O 3 reacts with B to form LaB 6 nanoparticles as effective flux pining centers. The improvement of the superconducting properties in codoped tapes can be attributed to the combined effects of improvement in H c2 and flux pinning. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  19. A technique for determining fast and thermal neutron flux densities in intense high-energy (8-30 MeV) photon fields

    International Nuclear Information System (INIS)

    Price, K.W.; Holeman, G.R.; Nath, R.

    1978-01-01

    A technique for measuring fast and thermal neutron fluxes in intense high-energy photon fields has been developed. Samples of phorphorous pentoxide are exposed to a mixed photon-neutron field. The irradiated samples are then dissolved in distilled water and their activation products are counted in a liquid scintillation spectrometer at 95-97% efficiency. The radioactive decay characteristics of the samples are then analyzed to determine fast and thermal neutron fluxes. Sensitivity of this neutron detector to high energy photons has been measured and found to be small. (author)

  20. 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)

  1. Energy conversion loops for flux-switching PM machine analysis

    NARCIS (Netherlands)

    Ilhan, E.; Motoasca, T.E.; Paulides, J.J.H.; Lomonova, E.

    2012-01-01

    Induction and synchronous machines have traditionally been the first choice of automotive manufacturers for electric/hybrid vehicles. However, these conventional machines are not able anymore to meet the increasing demands for a higher energy density due to space limitation in cars. Flux-switching

  2. Heat transfer for ultrahigh flux reactor

    International Nuclear Information System (INIS)

    Wadkins, R.P.; Lake, J.A.; Oh, C.H.

    1987-01-01

    The use of a uniquely designed nuclear reactor to supply neutrons for materials research is the focus of recent reactor design efforts. The biological, materials, and fundamental physics aspects of research require neutron fluxes much higher than present research and testing facilities can produce. The most advanced research using neutrons as probing detectors is being done in the High Flux Reactor at the Institut Laue Langeuin, France. The design of a reactor that can produce neutron fluxes of 1.0 x 10 16 n/cm 2 .s requires a relatively high power (300 MW range) and a small core volume (approximately 30 liters). This combination of power and volume leads to a high power density which places increased demands on thermal hydraulic margins

  3. Preadipocyte Factor-1 Levels Are Higher in Women with Hypothalamic Amenorrhea and Are Associated with Bone Mineral Content and Bone Mineral Density through a Mechanism Independent of Leptin

    Science.gov (United States)

    Aronis, Konstantinos N.; Kilim, Holly; Chamberland, John P.; Breggia, Anne; Rosen, Clifford

    2011-01-01

    Context: Preadipocyte factor 1 (pref-1) is increased in anorexia nervosa and is associated negatively with bone mineral density (BMD). No previous studies exist on pref-1 in women with exercise-induced hypothalamic amenorrhea (HA), which similar to anorexia nervosa, is an energy-deficiency state associated with hypoleptinemia. Objective: Our objective was to evaluate whether pref-1 levels are also elevated and associated with low BMD and to assess whether leptin regulates pref-1 levels in women with HA. Design: Study 1 was a double-blinded, placebo-controlled randomized clinical trial of metreleptin administration in women with HA. Study 2 was an open-label study of metreleptin administration in low physiological, supraphysiological, and pharmacological doses in healthy women volunteers. Setting and Patients: At Beth Israel Deaconess Medical Center, 20 women with HA and leptin levels higher than 5 ng/ml and nine healthy control women participated in study 1, and five healthy women participated in study 2. Intervention: For study 1, 20 HA subjects were randomized to receive either 0.08 mg/kg metreleptin (n = 11) or placebo (n = 9). For study 2, five healthy subjects received 0.01, 0.1, and 0.3 mg/kg metreleptin in both fed and fasting conditions for 1 and 3 d, respectively. Main Outcome Measures: Circulating pref-1 and leptin levels were measured. Results: Pref-1 was significantly higher in HA subjects vs. controls (P = 0.035) and negatively associated with BMD (ρ = −0.38; P < 0.01) and bone mineral content (ρ = −0.32; P < 0.05). Metreleptin administration did not alter pref-1 levels in any study reported herein. Conclusions: Pref-1 is higher in HA subjects than controls. Metreleptin administration at low physiological, supraphysiological, and pharmacological doses does not affect pref-1 levels, suggesting that hypoleptinemia is not responsible for higher pref-1 levels and that leptin does not regulate pref-1. PMID:21795455

  4. Preadipocyte factor-1 levels are higher in women with hypothalamic amenorrhea and are associated with bone mineral content and bone mineral density through a mechanism independent of leptin.

    Science.gov (United States)

    Aronis, Konstantinos N; Kilim, Holly; Chamberland, John P; Breggia, Anne; Rosen, Clifford; Mantzoros, Christos S

    2011-10-01

    Preadipocyte factor 1 (pref-1) is increased in anorexia nervosa and is associated negatively with bone mineral density (BMD). No previous studies exist on pref-1 in women with exercise-induced hypothalamic amenorrhea (HA), which similar to anorexia nervosa, is an energy-deficiency state associated with hypoleptinemia. Our objective was to evaluate whether pref-1 levels are also elevated and associated with low BMD and to assess whether leptin regulates pref-1 levels in women with HA. Study 1 was a double-blinded, placebo-controlled randomized clinical trial of metreleptin administration in women with HA. Study 2 was an open-label study of metreleptin administration in low physiological, supraphysiological, and pharmacological doses in healthy women volunteers. At Beth Israel Deaconess Medical Center, 20 women with HA and leptin levels higher than 5 ng/ml and nine healthy control women participated in study 1, and five healthy women participated in study 2. For study 1, 20 HA subjects were randomized to receive either 0.08 mg/kg metreleptin (n = 11) or placebo (n = 9). For study 2, five healthy subjects received 0.01, 0.1, and 0.3 mg/kg metreleptin in both fed and fasting conditions for 1 and 3 d, respectively. Circulating pref-1 and leptin levels were measured. Pref-1 was significantly higher in HA subjects vs. controls (P = 0.035) and negatively associated with BMD (ρ = -0.38; P < 0.01) and bone mineral content (ρ = -0.32; P < 0.05). Metreleptin administration did not alter pref-1 levels in any study reported herein. Pref-1 is higher in HA subjects than controls. Metreleptin administration at low physiological, supraphysiological, and pharmacological doses does not affect pref-1 levels, suggesting that hypoleptinemia is not responsible for higher pref-1 levels and that leptin does not regulate pref-1.

  5. Design comparison of single phase outer and inner-rotor hybrid excitation flux switching motor for hybrid electric vehicles

    Science.gov (United States)

    Mazlan, Mohamed Mubin Aizat; Sulaiman, Erwan; Husin, Zhafir Aizat; Othman, Syed Muhammad Naufal Syed; Khan, Faisal

    2015-05-01

    In hybrid excitation machines (HEMs), there are two main flux sources which are permanent magnet (PM) and field excitation coil (FEC). These HEMs have better features when compared with the interior permanent magnet synchronous machines (IPMSM) used in conventional hybrid electric vehicles (HEVs). Since all flux sources including PM, FEC and armature coils are located on the stator core, the rotor becomes a single piece structure similar with switch reluctance machine (SRM). The combined flux generated by PM and FEC established more excitation fluxes that are required to produce much higher torque of the motor. In addition, variable DC FEC can control the flux capabilities of the motor, thus the machine can be applied for high-speed motor drive system. In this paper, the comparisons of single-phase 8S-4P outer and inner rotor hybrid excitation flux switching machine (HEFSM) are presented. Initially, design procedures of the HEFSM including parts drawing, materials and conditions setting, and properties setting are explained. Flux comparisons analysis is performed to investigate the flux capabilities at various current densities. Then the flux linkages of PM with DC FEC of various DC FEC current densities are examined. Finally torque performances are analyzed at various armature and FEC current densities for both designs. As a result, the outer-rotor HEFSM has higher flux linkage of PM with DC FEC and higher average torque of approximately 10% when compared with inner-rotor HEFSM.

  6. Neutron flux monitoring device

    International Nuclear Information System (INIS)

    Shimazu, Yoichiro.

    1995-01-01

    In a neutron flux monitoring device, there are disposed a neutron flux measuring means for outputting signals in accordance with the intensity of neutron fluxes, a calculation means for calculating a self power density spectrum at a frequency band suitable to an object to be measured based on the output of the neutron flux measuring means, an alarm set value generation means for outputting an alarm set value as a comparative reference, and an alarm judging means for comparing the alarm set value with the outputted value of the calculation means to judge requirement of generating an alarm and generate an alarm in accordance with the result of the judgement. Namely, the time-series of neutron flux signals is put to fourier transformation for a predetermined period of time by the calculation means, and from each of square sums for real number component and imaginary number component for each of the frequencies, a self power density spectrum in the frequency band suitable to the object to be measured is calculated. Then, when the set reference value is exceeded, an alarm is generated. This can reliably prevent generation of erroneous alarm due to neutron flux noises and can accurately generate an alarm at an appropriate time. (N.H.)

  7. The correlation function for density perturbations in an expanding universe. III The three-point and predictions of the four-point and higher order correlation functions

    Science.gov (United States)

    Mcclelland, J.; Silk, J.

    1978-01-01

    Higher-order correlation functions for the large-scale distribution of galaxies in space are investigated. It is demonstrated that the three-point correlation function observed by Peebles and Groth (1975) is not consistent with a distribution of perturbations that at present are randomly distributed in space. The two-point correlation function is shown to be independent of how the perturbations are distributed spatially, and a model of clustered perturbations is developed which incorporates a nonuniform perturbation distribution and which explains the three-point correlation function. A model with hierarchical perturbations incorporating the same nonuniform distribution is also constructed; it is found that this model also explains the three-point correlation function, but predicts different results for the four-point and higher-order correlation functions than does the model with clustered perturbations. It is suggested that the model of hierarchical perturbations might be explained by the single assumption of having density fluctuations or discrete objects all of the same mass randomly placed at some initial epoch.

  8. Study on the stability of a single-phase natural circulation flow in a closed loop. Demonstrative experiments on the higher-mode density wave oscillation

    International Nuclear Information System (INIS)

    Nishihara, Takashi

    1997-01-01

    Single-phase natural circulation loops are very important systems driven by the density variation generated thermally and have various applications in energy systems. Many theoretical and experimental works have been carried out on them and it has been known that the oscillatory instability can occur under some conditions. Most of the works on the oscillatory instability have been limited to specific geometry of the loops and they have paid attention only to the instability of fundamental mode, which has the period approximately equal to the item that the fluid goes round the loop, hereinafter referred to as the typical period. The author had applied the linear stability analysis to the simplified rectangular loop to investigate the basic stability characteristics of a natural circulation flow in a closed loop. The results indicate that various higher-mode oscillatory instabilities can be caused with a period approximately equal to one nth of the typical period according to parameters such as the pressure loss coefficient, the locations of a heat source and a heat sink, and so on. In this report, experimental tests were carried out and it was demonstrated that the higher-mode oscillatory instability can be caused with features as predicted in the analysis. The stability analysis was applied to the geometry of the experimental apparatus. The analytical results and those of experiments were compared with regard to the mode and the region of the parameters to be unstable and they have a good agreement qualitatively. (author)

  9. Critical current densities and flux creep rate in Co-doped BaFe2As2 with columnar defects introduced by heavy-Ion irradiation

    International Nuclear Information System (INIS)

    Nakajima, Y.; Tsuchiya, Y.; Taen, T.; Yagyuda, H.; Tamegai, T.; Okayasu, S.; Sasase, M.; Kitamura, H.; Murakami, T.

    2010-01-01

    We report the formation of columnar defects in Co-doped BaFe 2 As 2 single crystals with different heavy-ion irradiations. The formation of columnar defects by 200 MeV Au ion irradiation is confirmed by transmission electron microscopy and their density is about 40% of the irradiation dose. Magneto-optical imaging and bulk magnetization measurements reveal that the critical current density J c is enhanced in the 200 MeV Au and 800 MeV Xe ion irradiated samples while J c is unchanged in the 200 MeV Ni ion irradiated sample. We also find that vortex creep rates are strongly suppressed by the columnar defects. We compare the effect of heavy-ion irradiation into Co-doped BaFe 2 As 2 and cuprate superconductors.

  10. Continuous magnetic flux pump

    Science.gov (United States)

    Hildebrandt, A. F.; Elleman, D. D.; Whitmore, F. C. (Inventor)

    1966-01-01

    A method and means for altering the intensity of a magnetic field by transposing flux from one location to the location desired fro the magnetic field are examined. The device described includes a pair of communicating cavities formed in a block of superconducting material, is dimensioned to be insertable into one of the cavities and to substantially fill the cavity. Magnetic flux is first trapped in the cavities by establishing a magnetic field while the superconducting material is above the critical temperature at which it goes superconducting. Thereafter, the temperature of the material is reduced below the critical value, and then the exciting magnetic field may be removed. By varying the ratios of the areas of the two cavities, it is possible to produce a field having much greater flux density in the second, smaller cavity, into which the flux transposed.

  11. 3D printed Ti6Al4V implant surface promotes bone maturation and retains a higher density of less aged osteocytes at the bone-implant interface.

    Science.gov (United States)

    Shah, Furqan A; Snis, Anders; Matic, Aleksandar; Thomsen, Peter; Palmquist, Anders

    2016-01-01

    For load-bearing orthopaedic applications, metal implants having an interconnected pore structure exhibit the potential to facilitate bone ingrowth and the possibility for reducing the stiffness mismatch between the implant and bone, thus eliminating stress-shielding effects. 3D printed solid and macro-porous Ti6Al4V implants were evaluated after six-months healing in adult sheep femora. The ultrastructural composition of the bone-implant interface was investigated using Raman spectroscopy and electron microscopy, in a correlative manner. The mineral crystallinity and the mineral-to-matrix ratios of the interfacial tissue and the native bone were found to be similar. However, lower Ca/P ratios, lower carbonate content, but higher proline, phenylalanine and tyrosine levels indicated that the interfacial tissue remained less mature. Bone healing was more advanced at the porous implant surface (vs. the solid implant surface) based on the interfacial tissue ν1 CO3(2-)/ν2 PO4(3-) ratio, phenylalanine and tyrosine levels approaching those of the native bone. The mechanosensing infrastructure in bone, the osteocyte lacuno-canalicular network, retained ∼40% more canaliculi per osteocyte lacuna, i.e., a 'less aged' morphology at the interface. The osteocyte density per mineralised surface area was ∼36-71% higher at the interface after extended healing periods. In osseointegration research, the success of an implant surface or design is commonly determined by quantifying the amount of new bone, rather than its maturation, composition and structure. This work describes a novel correlative methodology to investigate the ultrastructure and composition of bone formed around and within 3D printed Ti6Al4V implants having an interconnected open-pore structure. Raman spectroscopy demonstrates that the molecular composition of the interfacial tissue at different implant surfaces may vary, suggesting differences in the extent to which bone maturation occurs even after long

  12. Co-current Doping Effect of Nanoscale Carbon and Aluminum Nitride on Critical Current Density and Flux Pinning Properties of Bulk MgB2 Superconductors

    Science.gov (United States)

    Tripathi, D.; Dey, T. K.

    2018-05-01

    The effect of nanoscale aluminum nitride (n-AlN) and carbon (n-C) co-doping on superconducting properties of polycrystalline bulk MgB2 superconductor has been investigated. Polycrystalline pellets of MgB2, MgB2 + 0.5 wt% AlN (nano), MgB_{1.99}C_{0.01} and MgB_{1.99}C_{0.01} + 0.5 wt% AlN (nano) have been synthesized by a solid reaction process under inert atmosphere. The transition temperature (TC) estimated from resistivity measurement indicates only a small decrease for C (nano) and co-doped MgB2 samples. The magnetic field response of investigated samples has been measured at 4, 10, and 20 K in the field range ± 6 T. MgB2 pellets co-doped with 0.5 wt% n-AlN and 1 wt% n-C display appreciable enhancement in critical current density (J_C) of MgB2 in both low (≥ 3 times), as well as, high-field region (≥ 15 times). J_C versus H behavior of both pristine and doped MgB2 pellets is well explained in the light of the collective pinning model. Further, the normalized pinning force density f_p(= F_p/F_{pmax}) displays a fair correspondence with the scaling procedure proposed by Eisterer et al. Moreover, the scaled data of the pinning force density (i.e., f_p{-}h data) of the investigated pellets at different temperature are well interpreted by a modified Dew-Hughes expression reported by Sandu and Chee.

  13. Platelet activating factor-acylhydrolase (PAF-ase) activity is higher in serum of men than women and is related to levels of low density lipoprotein (LDL)

    International Nuclear Information System (INIS)

    Farr, R.S.; Howell, S.E.; Wardlow, M.L.

    1986-01-01

    PAF-ase is a specific serum enzyme that inactivates PAF by hydrolyzing acetate from the sn-2 position of the glycerol backbone. A reproducible PAF-ase activity assay was developed. A unit is based on the amount of serum required to release 3.61 +/- 0.042 pm 3 H-acetate from 10 pm 3 H-labeled PAF after incubation for 1 hr at 37 0 C. Assays on two single reference serums repeated 7 days were 0.63 +/- 0.013 U and 1.33 +/- 0.031 U. Serum from 20 normal men and 20 normal premenopausal women had significantly different (p = <0.001) levels of 1.32 +/- 0.072 U and 0.97 +/- 0.051 U respectively. They previously reported that PAF-ase is associated with B-lipoprotein. Therefore, total cholesterol (TC), LDL and high density lipoproteins (HDL) were determined on these 40 serums. Regression analysis revealed PAF-ase units were correlated with LDL (r = 0.740; p = < 0.001) and, parenthetically, with the TC (r = 0.620; p = < 0.001) but not with HDL. These correlations were similar for men and women. Thus, serum PAF-ase was partially controlled by serum LDL levels and the higher PAF-ase levels in serum from men were due in part to higher (p = < 0.01) LDL levels in men (147.6 +/- 6.9 mg/dl) as contrasted to women (119.0 +/- 7.6 mg/dl). PAF is a potent inflammatory, bronchoconstrictive and hypotensive agent. These data indicate that sex and serum LDL levels of subjects must be considered during future studies of the role of PAF vs PAF-ase in different disease states

  14. Critical current density and flux pinning in superconducting wires and coils of silver-clad Bi-Pb-Sr-Ca-Cu-O

    International Nuclear Information System (INIS)

    Dou, S.X.; Liu, H.K.; Apperley, M.H.; Song, K.H.; Sorrell, C.C.; Guo, S.J.; Loberg, B.; Easterling, K.E.

    1991-01-01

    The critical current density (J c ) of Ag-clad of Bi-Pb-Sr-Ca-Cu-O has been measured to be about 12,000 A/cm 2 at 77 K in zero field. This wire was rolled into a tape of thickness 0.1 mm and width of 2 to 3 mm, and a coil of 35 mm diameter was formed. The J c of this coil was measured to be about 2,000 A/cm 2 at 77 K over the full length (1.00 meter) of the coil. In this paper compositions, heat treatment parameters, and cold-deformation for enhancement of J c are presented. The microstructure is characterized and pinning interactions as well as possible weak links are emphasised. (orig.)

  15. Flux pinning properties of YBa2Cu3O7-δ thin films containing a high density of nanoprecipitates: A comparative study to reveal size effects

    Science.gov (United States)

    Yamasaki, Hirofumi; Yamada, Hiroshi

    2017-11-01

    Temperature dependence of critical current density Jc(H, T) was measured in moderate magnetic fields (H ⊥ film) in two thermally co-evaporated YBa2Cu3O7-δ (YBCO) thin films (A, B) and two YBCO films (C, D) deposited using a pulsed-laser deposition method. All sample films were grown epitaxially with the c-axis perpendicular to the surface of a single-crystalline substrate. Transmission electron microscopy observation revealed that these four films contained a high density of nanoprecipitates with typical sizes of 3.6 - 5.0 nm (A), 5.0 - 7.1 nm (B), 7.0 - 10.1 nm (C) and 8.7 - 14.3 nm (D). Films A and B contained very fine nanoprecipitates, whose typical diameters Dtyp are smaller than double the estimated Ginzburg-Landau coherence length 2ξab at T = 77 K, and exhibited a steep increase of Jc with decreasing temperature. Whereas, film D, which contained relatively large nanoprecipitates (Dtyp > 2ξab at T ≤ 70 K), exhibited a gradual increase in Jc. This led to a remarkable crossing of the Jc(T) curves. The temperature dependence of Jc(H//c) under a fixed magnetic field is approximated by Jc ∼ (1 - T/Tc)m(1 + T/Tc)2 where the index m is larger for films containing finer precipitates; that is, m(A) > m(B) > m(C) > m(D). This means that finer nanoprecipitates generally cause steeper Jc increase at low temperatures, which is the origin of the observed crossing phenomenon. The experimental results are reasonably explained by several theoretical models based on the direct summation of elementary pinning forces fp calculated by core pinning interactions.

  16. Modelling of Power Fluxes during Thermal Quenches

    International Nuclear Information System (INIS)

    Konz, C.; Coster, D. P.; Lackner, K.; Pautasso, G.

    2005-01-01

    Plasma disruptions, i. e. the sudden loss of magnetic confinement, are unavoidable, at least occasionally, in present day and future tokamaks. The expected energy fluxes to the plasma facing components (PFCs) during disruptions in ITER lie in the range of tens of GW/m''2 for timescales of about a millisecond. Since high energy fluxes can cause severe damage to the PFCs, their design heavily depends on the spatial and temporal distribution of the energy fluxes during disruptions. We investigate the nature of power fluxes during the thermal quench phase of disruptions by means of numerical simulations with the B2 SOLPS fluid code. Based on an ASDEX Upgrade shot, steady-state pre-disruption equilibria are generated which are then subjected to a simulated thermal quench by artificially enhancing the perpendicular transport in the ion and electron channels. The enhanced transport coefficients flows the Rechester and Rosenbluth model (1978) for ergodic transport in a tokamak with destroyed flux surfaces, i. e. χ, D∼const. xT''5/2 where the constants differ by the square root of the mass ratio for ions and electrons. By varying the steady-state neutral puffing rate we can modify the divertor conditions in terms of plasma temperature and density. Our numerical findings indicate that the disruption characteristics depend on the pre disruptive divertor conditions. We study the timescales and the spatial distribution of the divertor power fluxes. The simulated disruptions show rise and decay timescales in the range observed at ASDEX Upgrade. The decay timescale for the central electron temperature of ∼800 μs is typical for non-ITB disruptions. Varying the divertor conditions we find a distinct transition from a regime with symmetric power fluxes to inboard and outboard divertors to a regime where the bulk of the power flux goes to the outboard divertor. This asymmetry in the divertor peak fluxes for the higher puffing case is accompanied by a time delay between the

  17. Commissioning and modification of the low temperature scanning polarization microscope (TTSPM) and imaging of the local magnetic flux density distribution in superconducting niobium samples

    International Nuclear Information System (INIS)

    Gruenzweig, Matthias Sebastian Peter

    2014-01-01

    possible to image the magnetization reversal process and thus the formation (or destruction) and the migration of an ''Interfacial Domain Wall'' (IDW) in such a Fe 1-x Tb x / vertical stroke Co/Pt vertical stroke n -heterostructure. Part II of the dissertation is about the magneto-optical imaging of superconducting Niobium coplanar microwave resonators as well as of a Niobium single crystal. By means of the magneto-optical images of the resonators, important findings about magnetic hysteresis effects in such coplanar microwave resonators could be achieved. It was also possible to confirm the results of transmission spectroscopy experiments on those coplanar resonators, which were performed in a previous dissertation of Daniel Bothner. Additionally, it was possible to show that initially inserted Abrikosov vortices can be almost completely removed from the coplanar resonators again by properly cycling the magnetic field. On the basis of magneto-optical images of a 2 mm thick Niobium single crystal, it was possible to observe dendritic avalanches in a superconducting bulk material for the first time. Here, the dendritic avalanches only appear in a very narrow temperature interval of about a tenth of a Kelvin below the critical temperature T c of the Niobium single crystal. Below this threshold temperature the magnetic flux penetrates nearly homogeneously into the single crystal. The observed dendritic avalanches in the bulk single crystal near T c have features which are identical to those seen in thin films at low temperatures caused by thermomagnetic instability. Therefore, one can conclude that the dendritic avalanches in the single crystal are formed in a thin superconducting layer at the surface of the single crystal, which can be formed under certain conditions near T c .

  18. An Improved Seeding Algorithm of Magnetic Flux Lines Based on Data in 3D Space

    Directory of Open Access Journals (Sweden)

    Jia Zhong

    2015-05-01

    Full Text Available This paper will propose an approach to increase the accuracy and efficiency of seeding algorithms of magnetic flux lines in magnetic field visualization. To obtain accurate and reliable visualization results, the density of the magnetic flux lines should map the magnetic induction intensity, and seed points should determine the density of the magnetic flux lines. However, the traditional seeding algorithm, which is a statistical algorithm based on data, will produce errors when computing magnetic flux through subdivision of the plane. To achieve higher accuracy, more subdivisions should be made, which will reduce efficiency. This paper analyzes the errors made when the traditional seeding algorithm is used and gives an improved algorithm. It then validates the accuracy and efficiency of the improved algorithm by comparing the results of the two algorithms with results from the equivalent magnetic flux algorithm.

  19. Enhanced Flux Pinning and Critical Current Density via Incorporation of Self-Assembled Rare-Earth Barium Tantalate Nanocolumns within YBa2Cu3O7-δ Films

    Energy Technology Data Exchange (ETDEWEB)

    Wee, Sung Hun [ORNL; Goyal, Amit [ORNL; Specht, Eliot D [ORNL; Cantoni, Claudia [ORNL; Zuev, Yuri L [ORNL; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York; Cook, Sylvester W [ORNL

    2010-01-01

    We report rare earth barium tantalates, Ba2RETaO6 (BRETO, RE = rare earth elements) as a new class of additives for superior flux-pinning in YBa2Cu3O7- (YBCO) films. BRETO compounds have excellent chemical inertness to and large lattice mismatch with YBCO. This results in phase separation and strain minimization driven self-assembly of BRETO nanocolumns within YBCO films. YBCO+4 vol% Ba2GdTaO6 films show similar Tc to that of an un-doped film of ~ 88.3 K, a higher self-field Jc of 3.8 MA/cm2 at 77 K, and significantly improved in-field Jc higher by a factor of 1.5-6 over entire magnetic field and angular ranges.

  20. Use of sup(233)U for high flux reactors

    International Nuclear Information System (INIS)

    Sekimoto, Hiroshi; Liem, P.H.

    1991-01-01

    The feasibility design study on the graphite moderated gas cooled reactor as a high flux reactor has been performed. The core of the reactor is equipped with two graphite reflectors, i.e., the inner reflector and the outer reflector. The highest value of the thermal neutron flux and moderately high thermal neutron flux are expected to be achieved in the inner reflector region and in the outer reflector region respectively. This reactor has many merits comparing to the conventional high flux reactors. It has the inherent safety features associated with the modular high temperature reactors. Since the core is composed with pebble bed, the on-power refueling can be performed and the experiment time can be chosen as long as necessary. Since the thermal-to-fast flux ratio is large, the background neutron level is low and material damage induced by fast neutrons are small. The calculation was performed using a four groups diffusion approximation in a one-dimensional spherical geometry and a two-dimensional cylindrical geometry. By choosing the optimal values of the core-reflector geometrical parameters and moderator-to-fuel atomic density, high thermal neutron flux can be obtained. Because of the thermal neutron flux can be obtained. Because of the thermal design constraint, however, this design will produce a relatively large core volume (about 10 7 cc) and consequently a higher reactor power (100 MWth). Preliminary calculational results show that with an average power density of only 10 W/cc, maximum thermal neutron flux of 10 15 cm -2 s -1 can be achieved in the inner reflector. The eta value of 233 U is larger than 235 U. By introducing 233 U as the fissile material for this reactor, the thermal neutron flux level can be increased by about 15%. (author). 3 refs., 2 figs., 4 tabs

  1. Flux Pinning in Superconductors

    CERN Document Server

    Matsushita, Teruo

    2007-01-01

    The book covers the flux pinning mechanisms and properties and the electromagnetic phenomena caused by the flux pinning common for metallic, high-Tc and MgB2 superconductors. The condensation energy interaction known for normal precipitates or grain boundaries and the kinetic energy interaction proposed for artificial Nb pins in Nb-Ti, etc., are introduced for the pinning mechanism. Summation theories to derive the critical current density are discussed in detail. Irreversible magnetization and AC loss caused by the flux pinning are also discussed. The loss originally stems from the ohmic dissipation of normal electrons in the normal core driven by the electric field induced by the flux motion. The readers will learn why the resultant loss is of hysteresis type in spite of such mechanism. The influence of the flux pinning on the vortex phase diagram in high Tc superconductors is discussed, and the dependencies of the irreversibility field are also described on other quantities such as anisotropy of supercondu...

  2. Observation of a commensurate array of flux chains in tilted flux lattices in Bi-Sr-Ca-Cu-O single crystals

    International Nuclear Information System (INIS)

    Bolle, C.A.; Gammel, P.L.; Grier, D.G.; Murray, C.A.; Bishop, D.J.; Mitzi, D.B.; Kapitulnik, A.

    1991-01-01

    We report the observation of a novel flux-lattice structure, a commensurate array of flux-line chains. Our experiments consist of the magnetic decoration of the flux lattices in single crystals of Ba-Sr-Ca-Cu-O where the magnetic field is applied at an angle with respect to the conducting planes. For a narrow range of angles, the equilibrium structure is one with uniformly spaced chains with a higher line density of vortices than the background lattice. Our observations are in qualitative agreement with theories which suggest that, in strongly anisotropic materials the vortices develop an attractive interaction in tilted magnetic fields

  3. Fabrication of Anodic Aluminum Oxide Membrane for High Heat Flux Evaporation

    OpenAIRE

    McGrath, Kristine

    2016-01-01

    As electronics become more powerful and have higher energy densities, it is becoming more and more necessary to find solutions to dissipate these high heat fluxes. One solution to this problem is nanopore evaporative cooling. Based on current literature, the experimental data is far below what is expected from the theoretical calculations.In this thesis, the experimental results produced heat fluxes much closer to the theoretical values. Experimentally, a maximum heat dissipation of 103 W was...

  4. Carbon dioxide fluxes from an urban area in Beijing

    Science.gov (United States)

    Song, Tao; Wang, Yuesi

    2012-03-01

    A better understanding of urban carbon dioxide (CO 2) emissions is important for quantifying urban contributions to the global carbon budget. From January to December 2008, CO 2 fluxes were measured, by eddy covariance at 47 m above ground on a meteorological tower in a high-density residential area in Beijing. The results showed that the urban surface was a net source of CO 2 in the atmosphere. Diurnal flux patterns were similar to those previously observed in other cities and were largely influenced by traffic volume. Carbon uptake by both urban vegetation during the growing season and the reduction of fuel consumption for domestic heating resulted in less-positive daily fluxes in the summer. The average daily flux measured in the summer was 0.48 mg m - 2 s - 1 , which was 82%, 35% and 36% lower than those in the winter, spring and autumn, respectively. The reduction of vehicles on the road during the 29th Olympic and Paralympic Games had a significant impact on CO 2 flux. The flux of 0.40 mg m - 2 s - 1 for September 2008 was approximately 0.17 mg m - 2 s - 1 lower than the flux for September 2007. Annual CO 2 emissions from the study site were estimated at 20.6 kg CO 2 m - 2 y - 1 , considerably higher than yearly emissions obtained from other urban and suburban landscapes.

  5. Force sensor using changes in magnetic flux

    Science.gov (United States)

    Pickens, Herman L. (Inventor); Richard, James A. (Inventor)

    2012-01-01

    A force sensor includes a magnetostrictive material and a magnetic field generator positioned in proximity thereto. A magnetic field is induced in and surrounding the magnetostrictive material such that lines of magnetic flux pass through the magnetostrictive material. A sensor positioned in the vicinity of the magnetostrictive material measures changes in one of flux angle and flux density when the magnetostrictive material experiences an applied force that is aligned with the lines of magnetic flux.

  6. Design of a Modular E-Core Flux Concentrating Axial Flux Machine: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Husain, Tausif; Sozer, Yilmaz; Husain, Iqbal; Muljadi, Eduard

    2015-08-24

    In this paper a novel E-Core axial flux machine is proposed. The machine has a double-stator, single-rotor configuration with flux-concentrating ferrite magnets and pole windings across each leg of an E-Core stator. E-Core stators with the proposed flux-concentrating rotor arrangement result in better magnet utilization and higher torque density. The machine also has a modular structure facilitating simpler construction. This paper presents a single-phase and a three-phase version of the E-Core machine. Case studies for a 1.1-kW, 400-rpm machine for both the single-phase and three-phase axial flux machines are presented. The results are verified through 3D finite element analysis. facilitating simpler construction. This paper presents a single-phase and a three-phase version of the E-Core machine. Case studies for a 1.1-kW, 400-rpm machine for both the single-phase and three-phase axial flux machines are presented. The results are verified through 3D finite element analysis.

  7. Higher expression of CCL2, CCL4, CCL5, CCL21, and CXCL8 chemokines in the skin associated with parasite density in canine visceral leishmaniasis.

    Directory of Open Access Journals (Sweden)

    Daniel Menezes-Souza

    Full Text Available BACKGROUND: The immune response in the skin of dogs infected with Leishmania infantum is poorly understood, and limited studies have described the immunopathological profile with regard to distinct levels of tissue parasitism and the clinical progression of canine visceral leishmaniasis (CVL. METHODOLOGY/PRINCIPAL FINDINGS: A detailed analysis of inflammatory cells (neutrophils, eosinophils, mast cells, lymphocytes, and macrophages as well as the expression of chemokines (CCL2, CCL4, CCL5, CCL13, CCL17, CCL21, CCL24, and CXCL8 was carried out in dermis skin samples from 35 dogs that were naturally infected with L. infantum. The analysis was based on real-time polymerase chain reaction (PCR in the context of skin parasitism and the clinical status of CVL. We demonstrated increased inflammatory infiltrate composed mainly of mononuclear cells in the skin of animals with severe forms of CVL and high parasite density. Analysis of the inflammatory cell profile of the skin revealed an increase in the number of macrophages and reductions in lymphocytes, eosinophils, and mast cells that correlated with clinical progression of the disease. Additionally, enhanced parasite density was correlated with an increase in macrophages and decreases in eosinophils and mast cells. The chemokine mRNA expression demonstrated that enhanced parasite density was positively correlated with the expression of CCL2, CCL4, CCL5, CCL21, and CXCL8. In contrast, there was a negative correlation between parasite density and CCL24 expression. CONCLUSIONS/SIGNIFICANCE: These findings represent an advance in the knowledge about skin inflammatory infiltrates in CVL and the systemic consequences. Additionally, the findings may contribute to the design of new and more efficient prophylactic tools and immunological therapies against CVL.

  8. ALMA Observations of Gas-rich Galaxies in z ∼ 1.6 Galaxy Clusters: Evidence for Higher Gas Fractions in High-density Environments

    Energy Technology Data Exchange (ETDEWEB)

    Noble, A. G.; McDonald, M. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Muzzin, A. [Department of Physics and Astronomy, York University, 4700 Keele Street, Toronto, ON MJ3 1P3 (Canada); Nantais, J. [Departamento de Ciencias Físicas, Universidad Andres Bello, Fernandez Concha 700, Las Condes 7591538, Santiago, Región Metropolitana (Chile); Rudnick, G. [The University of Kansas, Department of Physics and Astronomy, 1251 Wescoe Hall Drive, Lawrence, KS 66045 (United States); Van Kampen, E.; Manilla-Robles, A. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München (Germany); Webb, T. M. A.; Delahaye, A. [Department of Physics, McGill University, 3600 rue University, Montréal, QC H3A 2T8 (Canada); Wilson, G.; DeGroot, A.; Foltz, R. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Yee, H. K. C. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Boone, K.; Hayden, B.; Perlmutter, S. [Department of Physics, University of California Berkeley, 366 LeConte Hall, MC 7300, Berkeley, CA 94720-7300 (United States); Cooper, M. C. [Department of Physics and Astronomy, University of California, Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697 (United States); Demarco, R. [Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción, Región del Biobío (Chile); Lidman, C., E-mail: noble@mit.edu [Australian Astronomical Observatory, 105 Delhi Road, North Ryde, NSW 2113 (Australia)

    2017-06-20

    We present ALMA CO (2–1) detections in 11 gas-rich cluster galaxies at z ∼ 1.6, constituting the largest sample of molecular gas measurements in z > 1.5 clusters to date. The observations span three galaxy clusters, derived from the Spitzer Adaptation of the Red-sequence Cluster Survey. We augment the >5 σ detections of the CO (2–1) fluxes with multi-band photometry, yielding stellar masses and infrared-derived star formation rates, to place some of the first constraints on molecular gas properties in z ∼ 1.6 cluster environments. We measure sizable gas reservoirs of 0.5–2 × 10{sup 11} M {sub ☉} in these objects, with high gas fractions ( f {sub gas}) and long depletion timescales ( τ ), averaging 62% and 1.4 Gyr, respectively. We compare our cluster galaxies to the scaling relations of the coeval field, in the context of how gas fractions and depletion timescales vary with respect to the star-forming main sequence. We find that our cluster galaxies lie systematically off the field scaling relations at z = 1.6 toward enhanced gas fractions, at a level of ∼4 σ , but have consistent depletion timescales. Exploiting CO detections in lower-redshift clusters from the literature, we investigate the evolution of the gas fraction in cluster galaxies, finding it to mimic the strong rise with redshift in the field. We emphasize the utility of detecting abundant gas-rich galaxies in high-redshift clusters, deeming them as crucial laboratories for future statistical studies.

  9. A Study on the Design of PM Exited Transverse Flux Linear Motor for Ropeless Elevator

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Do Hyun; Bang, Deok Je; Kim, Jong Moo; Jeong, Yeon Ho [Korea Electrotechnology Research Institute (Korea); Kim, Moon Hwan [Silla University (Korea)

    2000-03-01

    The topological investigations regarding magnetic circuit geometry and winding form of the transverse flux machine have brought up a variety of constructable arrangements with different features for several types of application[1, 2]. Here with, a novel PM-exited linear motor with inner mover, based on the transverse flux configuration leads to a considerable increase in power density for moving part. In this study we designed PM-exited transverse flux linear motor for ropeless elevator, whose output power density is higher and weight is lighter than conventional linear synchronous motors, When the designed motor in this study is applied to ropeless elevator, it is possible to increase power density more than 400% comparing with PM exited linear synchronous motor. The result of this study can be utilized for ropeless elevator or gearless direct linear moving system with high output[3]. (author). 8 refs., 9 figs., 4 tabs.

  10. Analyzing distinctive rotor poles of the axial flux PM motors by using 3D-FEA in view of the magnetic equivalent circuit

    Directory of Open Access Journals (Sweden)

    Emrah Cetin

    2017-10-01

    Full Text Available Higher efficiency is always a desire for the electric machines researchers. One serious candidate is the axial flux permanent magnet motor to achieve that. These machines have advantages on power and torque density profile. This study aims to analyse the performances of the different rotor poles’ characteristics of the axial flux permanent magnet machines. The magnetic equivalent circuit designed and placed into the single gap axial flux permanent magnet machine to fathom the machine characteristic. The proposed rotors magnet poles are investigated in the view of the torque ripple reduction, back EMF waveforms and flux density distribution by using finite element analysis. Four different designs are compared. 3D analysis is used for FEA simulations. Torque ripple, back emf and magnetic flux distribution waveforms are obtained from the 3D FEA analysis. As a result, the proposed rotors are practicable and situated for higher performance.

  11. Comparisons between TiO2- and SiO2-flux assisted TIG welding processes.

    Science.gov (United States)

    Tseng, Kuang-Hung; Chen, Kuan-Lung

    2012-08-01

    This study investigates the effects of flux compounds on the weld shape, ferrite content, and hardness profile in the tungsten inert gas (TIG) welding of 6 mm-thick austenitic 316 L stainless steel plates, using TiO2 and SiO2 powders as the activated fluxes. The metallurgical characterizations of weld metal produced with the oxide powders were evaluated using ferritoscope, optical microscopy, and Vickers microhardness test. Under the same welding parameters, the penetration capability of TIG welding with TiO2 and SiO2 fluxes was approximately 240% and 292%, respectively. A plasma column made with SiO2 flux exhibited greater constriction than that made with TiO2 flux. In addition, an anode root made with SiO2 flux exhibited more condensation than that made with TiO2 flux. Results indicate that energy density of SiO2-flux assisted TIG welding is higher than that of TiO2-flux assisted TIG welding.

  12. Critical flux determination by flux-stepping

    DEFF Research Database (Denmark)

    Beier, Søren; Jonsson, Gunnar Eigil

    2010-01-01

    In membrane filtration related scientific literature, often step-by-step determined critical fluxes are reported. Using a dynamic microfiltration device, it is shown that critical fluxes determined from two different flux-stepping methods are dependent upon operational parameters such as step...... length, step height, and.flux start level. Filtrating 8 kg/m(3) yeast cell suspensions by a vibrating 0.45 x 10(-6) m pore size microfiltration hollow fiber module, critical fluxes from 5.6 x 10(-6) to 1.2 x 10(-5) m/s have been measured using various step lengths from 300 to 1200 seconds. Thus......, such values are more or less useless in itself as critical flux predictors, and constant flux verification experiments have to be conducted to check if the determined critical fluxes call predict sustainable flux regimes. However, it is shown that using the step-by-step predicted critical fluxes as start...

  13. Effects of slotting and unipolar flux on magnetic pull in a two-pole induction motor with an extra four-pole stator winding

    Energy Technology Data Exchange (ETDEWEB)

    Sinervo, A.

    2013-06-01

    This thesis is about the radial magnetic forces between the rotor and stator in twopole induction machines. The magnetic forces arise from rotor eccentricity. The asymmetric air-gap makes the flux density on one side of the rotor stronger than on the opposite side. This produces magnetic pull. The magnetic flux density distribution in the air-gap can be expressed with spatial harmonics, i.e. flux densities with different pole-pair numbers. In two-pole machines, the main part of the magnetic force is produced by the interaction of two- and fourpole flux unless the four-pole flux is damped by parallel paths in the stator winding or an extra four-pole stator winding. The rest of the force comes from the interaction of two-pole and unipolar flux and from the higher harmonics of the air-gap flux of which the slot harmonics are a major part. The force caused by the higher harmonics and the unipolar flux is studied in the case where a four-pole stator winding is used to reduce the four-pole flux. The higher harmonics are found to produce, in addition to the traditional unbalanced magnetic pull, a force similar to the effect of the unipolar flux and the two can be distinguished only by measuring the unipolar flux. In measurements at various operation points, the higher harmonics are found to produce much more force than the unipolar flux and two-pole flux but the unipolar flux is still significant. The four-pole winding also is used to actively control the four-pole flux and the magnetic forces. Designing the controller requires a low order model of the system. Such a model is derived and the effect of the slot harmonics and the unipolar flux are included in the model. Different measurements techniques and methods are presented to identify and validate the control model. The operation point dependence of the system dynamics is studied via measurements. All results are obtained from a 30 kW test motor. The rotor of the test machine has a long flexible shaft on external

  14. Seasonality of Overstory and Understory Fluxes in a Semi-Arid Oak Savanna: What can be Learned from Comparing Measured and Modeled Fluxes?

    Science.gov (United States)

    Raz-Yaseef, N.; Sonnentag, O.; Kobayashi, H.; Chen, J. M.; Verfaillie, J. G.; Ma, S.; Baldocchi, D. D.

    2011-12-01

    Semi-arid climates experience large seasonal and inter-annual variability in radiation and precipitation, creating natural conditions adequate to study how year-to-year changes affect atmosphere-biosphere fluxes. Especially, savanna ecosystems, that combine tree and below-canopy components, create a unique environment in which phenology dramatically changes between seasons. We used a 10-year flux database in order to define seasonal and interannual variability of climatic inputs and fluxes, and evaluate model capability to reproduce observed variability. This is based on the perception that model capability to construct the deviation, and not the average, is important in order to correctly predict ecosystem sensitivity to climate change. Our research site is a low density and low LAI (0.8) semi-arid savanna, located at Tonzi Ranch, Northern California. In this system, trees are active during the warm season (Mar - Oct), and grasses are active during the wet season (Dec - May). Measurements of carbon and water fluxes above and below the tree canopy using eddy covariance and supplementary measurements have been made since 2001. Fluxes were simulated using bio-meteorological process-oriented ecosystem models: BEPS and 3D-CAONAK. Models were partly capable of reproducing fluxes on daily scales (R2=0.66). We then compared model outputs for different ecosystem components and seasons, and found distinct seasons with high correlations while other seasons were purely represented. Comparison was much higher for ET than for GPP. The understory was better simulated than the overstory. CANOAK overestimated spring understory fluxes, probably due to the capability to directly calculated 3D radiative transfer. BEPS underestimated spring understory fluxes, following the pre-description of grass die-off. Both models underestimated peak spring overstory fluxes. During winter tree dormant, modeled fluxes were null, but occasional high fluxes of both ET and GPP were measured following

  15. Heat Flux Inhibition by Whistlers: Experimental Confirmation

    International Nuclear Information System (INIS)

    Eichler, D.

    2002-01-01

    Heat flux in weakly magnetized collisionless plasma is, according to theoretical predictions, limited by whistler turbulence that is generated by heat flux instabilities near threshold. Observations of solar wind electrons by Gary and coworkers appear to confirm the limit on heat flux as being roughly the product of the magnetic energy density and the electron thermal velocity, in agreement with prediction (Pistinner and Eichler 1998)

  16. Modeling radon flux from the earth's surface

    International Nuclear Information System (INIS)

    Schery, S.D.; Wasiolek, M.A.

    1998-01-01

    We report development of a 222 Rn flux density model and its use to estimate the 222 Rn flux density over the earth's land surface. The resulting maps are generated on a grid spacing of 1 0 x 1 0 using as input global data for soil radium, soil moisture, and surface temperature. While only a first approximation, the maps suggest a significant regional variation (a factor of three is not uncommon) and a significant seasonal variation (a factor of two is not uncommon) in 222 Rn flux density over the earth's surface. The estimated average global flux density from ice-free land is 34 ± 9 mBq m -2 s -1 . (author)

  17. Design and analysis of a 3D-flux flux-switching permanent magnet machine with SMC cores and ferrite magnets

    Directory of Open Access Journals (Sweden)

    Chengcheng Liu

    2017-05-01

    Full Text Available Since permanent magnets (PM are stacked between the adjacent stator teeth and there are no windings or PMs on the rotor, flux-switching permanent magnet machine (FSPMM owns the merits of good flux concentrating and robust rotor structure. Compared with the traditional PM machines, FSPMM can provide higher torque density and better thermal dissipation ability. Combined with the soft magnetic composite (SMC material and ferrite magnets, this paper proposes a new 3D-flux FSPMM (3DFFSPMM. The topology and operation principle are introduced. It can be found that the designed new 3DFFSPMM has many merits over than the traditional FSPMM for it can utilize the advantages of SMC material. Moreover, the PM flux of this new motor can be regulated by using the mechanical method. 3D finite element method (FEM is used to calculate the magnetic field and parameters of the motor, such as flux density, inductance, PM flux linkage and efficiency map. The demagnetization analysis of the ferrite magnet is also addressed to ensure the safety operation of the proposed motor.

  18. Discrimination of neutrons and gamma quanta with the aid of their power density spectra

    International Nuclear Information System (INIS)

    Buchmueller, R.

    1977-01-01

    The paper introduces a method of using only one fission chamber to discriminate the neutron flux against the gamma flux. The gamma chamber current may be several orders of magnitude higher than the neutron chamber current. In specially dimensioned fission chambers the neutrons and gamma quanta are made to generate different current pulses. Discrimination becomes possible by recording the power density spectrum of the mixture of pulses over a broad frequency range ( [de

  19. Ultrahigh Flux Thin Film Boiling Heat Transfer Through Nanoporous Membranes.

    Science.gov (United States)

    Wang, Qingyang; Chen, Renkun

    2018-05-09

    Phase change heat transfer is fundamentally important for thermal energy conversion and management, such as in electronics with power density over 1 kW/cm 2 . The critical heat flux (CHF) of phase change heat transfer, either evaporation or boiling, is limited by vapor flux from the liquid-vapor interface, known as the upper limit of heat flux. This limit could in theory be greater than 1 kW/cm 2 on a planar surface, but its experimental realization has remained elusive. Here, we utilized nanoporous membranes to realize a new "thin film boiling" regime that resulted in an unprecedentedly high CHF of over 1.2 kW/cm 2 on a planar surface, which is within a factor of 4 of the theoretical limit, and can be increased to a higher value if mechanical strength of the membranes can be improved (demonstrated with 1.85 kW/cm 2 CHF in this work). The liquid supply is achieved through a simple nanoporous membrane that supports the liquid film where its thickness automatically decreases as heat flux increases. The thin film configuration reduces the conductive thermal resistance, leads to high frequency bubble departure, and provides separate liquid-vapor pathways, therefore significantly enhances the heat transfer. Our work provides a new nanostructuring approach to achieve ultrahigh heat flux in phase change heat transfer and will benefit both theoretical understanding and application in thermal management of high power devices of boiling heat transfer.

  20. Sunspots and the physics of magnetic flux tubes. II. Aerodynamic drag

    International Nuclear Information System (INIS)

    Parker, E.N.

    1979-01-01

    The aerodynamic drag on a slender flux tube stretched vertically across a convective cell may push the flux tube into the updrafts or into the downdrafts, depending on the density stratification of the convecting fluid and the asymmetry of the fluid motions. The drag is approximately proportional to the local kinetic energy density, so the density stratification weights the drag in favor of the upper layers where the density is low, tending to push the vertical tube into the downdrafts. If, however, the horizontal motions in the convective cell are concentrated toward the bottom of the cell, they may dominate over the upper layers, pushing the tube into the updrafts. In the simple, idealized circumstance of a vertical tube extending across a fluid of uniform density in a convective cell that is symmetric about its midplane, the net aerodynamic drag vanishes in lowest order. The higher order contributions, including the deflection of the tube, then provide a nonvanishing force pushing the tube into a stable equilibrium midway between the updraft and the downdraft.It is pointed out that in the strongly stratified convective zone of the Sun, a downdraft herds flux tubes together into a cluster, while an updraft disperses them. To account for the observed strong cohesion of the cluster of flux tubes that make up a sunspot, we propose a downdraft of the order 2 km s - 1 through the cluster of seprate tubes beneath the sunspot

  1. Higher glandular trichome density in tomato leaflets and repellence to spider mites Alta densidade de tricomas glandulares em tomateiro e aumento da repelência a ácaros rajados

    Directory of Open Access Journals (Sweden)

    Wilson Roberto Maluf

    2007-09-01

    Full Text Available The objective of this work was to evaluate the feasibility of selection for higher glandular trichome densities, as an indirect criterion of selection for increasing repellence to spider mites Tetranychus urticae, in tomato populations derived from an interspecific cross between Lycopersicon esculentum x L. hirsutum var. glabratum PI 134417. Trichome densities were evaluated in 19 genotypes, including 12 from advanced backcross populations, derived from the original cross L. esculentum x L. hirsutum var. glabratum PI 134417. Counts were made both on the adaxial and abaxial leaf surfaces, and trichomes were classified into glandular types IV and VI, other glandular types (types I+VII, and nonglandular types. Mite repellence was measured by distances walked by mites onto the tomato leaf surface after 20, 40 and 60 min. Spider mite repellence biotests indicated that higher densities of glandular trichomes (especially type VI decreased the distances walked by the mites onto the tomato leaf surface. Selection of plants with higher densities of glandular trichomes can be an efficient criterion to obtain tomato genotypes with higher resistance (repellence to spider mites.O objetivo deste trabalho foi avaliar a eficiência da seleção para maior densidade de tricomas glandulares na resistência (repelência ao ácaro Tetranychus urticae, em populações de tomate derivadas do cruzamento interespecífico Lycopersicon esculentum x L. hirsutum var. glabratum PI 134417. Foram avaliados 19 genótipos quanto à densidade de tricomas, que incluíram 12 derivados de populações avançadas de retrocruzamentos, obtidos a partir do cruzamento original L. esculentum x L. hirsutum var. glabratum PI 134417. Nas faces abaxial e adaxial dos folíolos, realizaram-se as contagens e os tricomas foram classificados em glandulares tipo IV e VI, outros glandulares (tipo I e VII e não glandulares. A repelência aos ácaros foi medida pela distância média, percorrida pelo

  2. 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.

  3. Fueling with edge recycling to high-density in DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, A.W., E-mail: leonard@fusion.gat.com [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States); Elder, J.D. [University of Toronto Institute of Aerospace Studies, Toronto, Canada M3H 5T6 (Canada); Canik, J.M. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Groebner, R.J.; Osborne, T.H. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States)

    2013-07-15

    Pedestal fueling through edge recycling is examined with the interpretive OEDGE code for high-density discharges in DIII-D. A high current, high-density discharge is found to have a similar radial ion flux profile through the pedestal to a lower current, lower density discharge. The higher density discharge, however, has a greater density gradient indicating a pedestal particle diffusion coefficient that scales near linear with 1/I{sub p}. The time dependence of density profile is taken into account in the analysis of a discharge with low frequency ELMs. The time-dependent analysis indicates that the inferred neutral ionization source is inadequate to account for the increase in the density profile between ELMs, implying an inward density convection, or density pinch, near the top of the pedestal.

  4. Fast-Rate Capable Electrode Material with Higher Energy Density than LiFePO4: 4.2V LiVPO4F Synthesized by Scalable Single-Step Solid-State Reaction.

    Science.gov (United States)

    Kim, Minkyung; Lee, Seongsu; Kang, Byoungwoo

    2016-03-01

    Use of compounds that contain fluorine (F) as electrode materials in lithium ion batteries has been considered, but synthesizing single-phase samples of these compounds is a difficult task. Here, it is demonstrated that a simple scalable single-step solid-state process with additional fluorine source can obtain highly pure LiVPO 4 F. The resulting material with submicron particles achieves very high rate capability ≈100 mAh g -1 at 60 C-rate (1-min discharge) and even at 200 C-rate (18 s discharge). It retains superior capacity, ≈120 mAh g -1 at 10 C charge/10 C discharge rate (6-min) for 500 cycles with >95% retention efficiency. Furthermore, LiVPO 4 F shows low polarization even at high rates leading to higher operating potential >3.45 V (≈3.6 V at 60 C-rate), so it achieves high energy density. It is demonstrated for the first time that highly pure LiVPO 4 F can achieve high power capability comparable to LiFePO 4 and much higher energy density (≈521 Wh g -1 at 20 C-rate) than LiFePO 4 even without nanostructured particles. LiVPO 4 F can be a real substitute of LiFePO 4.

  5. Resistive flux saving and current profile control during lower hybrid waves assisted current rise in TORE SUPRA

    International Nuclear Information System (INIS)

    van Houtte, D.; Hoang, G.T.; Joffrin, E.; Lecoustey, P.; Moreau, D.; Parlange, F.; Tonon, G.; Vallet, J.C.

    1992-01-01

    Resistive flux saving at densities n e = (1 - 2) x 10 19 m -3 has been studied. High flux saving efficiency (0.7 x 10 13 Wb/J/m -1 ) can be achieved for a low rf power (P LH = 0.5 MW) due to the beneficial effect of the electric field on the suprathermal electrons. However for power higher than 1 MW, the efficiency is 0.25 x 10 13 Wb/J/m -1 . This flux saving efficiency is comparable to the one obtained during the flat top phase. The application of the LH power during a low density current ramp-up tends to peak the electron temperature and current density profiles. The rf power level, the parallel wavenumber and the current ramp rate allow to control the trajectories of the plasma discharges during the current rise inside the MHD stable domain

  6. The measurements of thermal neutron flux distribution in a paraffin

    Indian Academy of Sciences (India)

    The term `thermal flux' implies a Maxwellian distribution of velocity and energy corresponding to the most probable velocity of 2200 ms-1 at 293.4 K. In order to measure the thermal neutron flux density, the foil activation method was used. Thermal neutron flux determination in paraffin phantom by counting the emitted rays of ...

  7. A statistical model for horizontal mass flux of erodible soil

    International Nuclear Information System (INIS)

    Babiker, A.G.A.G.; Eltayeb, I.A.; Hassan, M.H.A.

    1986-11-01

    It is shown that the mass flux of erodible soil transported horizontally by a statistically distributed wind flow has a statistical distribution. Explicit expression for the probability density function, p.d.f., of the flux is derived for the case in which the wind speed has a Weibull distribution. The statistical distribution for a mass flux characterized by a generalized Bagnold formula is found to be Weibull for the case of zero threshold speed. Analytic and numerical values for the average horizontal mass flux of soil are obtained for various values of wind parameters, by evaluating the first moment of the flux density function. (author)

  8. Radon flux measurement methodologies

    International Nuclear Information System (INIS)

    Nielson, K.K.; Rogers, V.C.

    1984-01-01

    Five methods for measuring radon fluxes are evaluated: the accumulator can, a small charcoal sampler, a large-area charcoal sampler, the ''Big Louie'' charcoal sampler, and the charcoal tent sampler. An experimental comparison of the five flux measurement techniques was also conducted. Excellent agreement was obtained between the measured radon fluxes and fluxes predicted from radium and emanation measurements

  9. Rapid reconnection of flux lines

    International Nuclear Information System (INIS)

    Samain, A.

    1982-01-01

    The rapid reconnection of flux lines in an incompressible fluid through a singular layer of the current density is discussed. It is shown that the liberated magnetic energy must partially appear in the form of plasma kinetic energy. A laminar structure of the flow is possible, but Alfven velocity must be achieved in eddies of growing size at the ends of the layer. The gross structure of the flow and the magnetic configuration may be obtained from variational principles. (author)

  10. Dependence of Core and Extended Flux on Core Dominance ...

    Indian Academy of Sciences (India)

    Abstract. Based on two extragalactic radio source samples, the core dominance parameter is calculated, and the correlations between the core/extended flux density and core dominance parameter are investi- gated. When the core dominance parameter is lower than unity, it is linearly correlated with the core flux density, ...

  11. Investigation of a tubular dual-stator flux-switching permanent-magnet linear generator for free-piston energy converter

    Science.gov (United States)

    Sui, Yi; Zheng, Ping; Tong, Chengde; Yu, Bin; Zhu, Shaohong; Zhu, Jianguo

    2015-05-01

    This paper describes a tubular dual-stator flux-switching permanent-magnet (PM) linear generator for free-piston energy converter. The operating principle, topology, and design considerations of the machine are investigated. Combining the motion characteristic of free-piston Stirling engine, a tubular dual-stator PM linear generator is designed by finite element method. Some major structural parameters, such as the outer and inner radii of the mover, PM thickness, mover tooth width, tooth width of the outer and inner stators, etc., are optimized to improve the machine performances like thrust capability and power density. In comparison with conventional single-stator PM machines like moving-magnet linear machine and flux-switching linear machine, the proposed dual-stator flux-switching PM machine shows advantages in higher mass power density, higher volume power density, and lighter mover.

  12. Role of plasma enhanced atomic layer deposition reactor wall conditions on radical and ion substrate fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Sowa, Mark J., E-mail: msowa@ultratech.com [Ultratech/Cambridge NanoTech, 130 Turner Street, Building 2, Waltham, Massachusetts 02453 (United States)

    2014-01-15

    Chamber wall conditions, such as wall temperature and film deposits, have long been known to influence plasma source performance on thin film processing equipment. Plasma physical characteristics depend on conductive/insulating properties of chamber walls. Radical fluxes depend on plasma characteristics as well as wall recombination rates, which can be wall material and temperature dependent. Variations in substrate delivery of plasma generated species (radicals, ions, etc.) impact the resulting etch or deposition process resulting in process drift. Plasma enhanced atomic layer deposition is known to depend strongly on substrate radical flux, but film properties can be influenced by other plasma generated phenomena, such as ion bombardment. In this paper, the chamber wall conditions on a plasma enhanced atomic layer deposition process are investigated. The downstream oxygen radical and ion fluxes from an inductively coupled plasma source are indirectly monitored in temperature controlled (25–190 °C) stainless steel and quartz reactors over a range of oxygen flow rates. Etch rates of a photoresist coated quartz crystal microbalance are used to study the oxygen radical flux dependence on reactor characteristics. Plasma density estimates from Langmuir probe ion saturation current measurements are used to study the ion flux dependence on reactor characteristics. Reactor temperature was not found to impact radical and ion fluxes substantially. Radical and ion fluxes were higher for quartz walls compared to stainless steel walls over all oxygen flow rates considered. The radical flux to ion flux ratio is likely to be a critical parameter for the deposition of consistent film properties. Reactor wall material, gas flow rate/pressure, and distance from the plasma source all impact the radical to ion flux ratio. These results indicate maintaining chamber wall conditions will be important for delivering consistent results from plasma enhanced atomic layer deposition

  13. Flux dependency of particulate/colloidal fouling in seawater reverse osmosis systems

    KAUST Repository

    Salinas Rodríguez, S. G.

    2012-01-01

    Fouling is the main operational problem in seawater reverse osmosis systems (SWRO). Particulate fouling is traditionally measured through the silt density index (SDI) and through the modified fouling index (MFI). In recent years, ultrafiltration membranes were used successfully at constant flux-MFI-UF-to measure particulate/colloidal fouling potential and tested in sea water applications. Furthermore, constant flux operation allows predicting the rate of fouling in RO systems. The objectives of this study are: (1) to measure the flux effect in MFI-UF with different membranes (100, 30 and 10 kDa) for raw seawater and pre-treated water before reverse osmosis in three different locations; (2) to study the particulate and colloidal fouling potential of seawater in reverse osmosis systems; (3) to project the increase in pressure due to cake resistance in reverse osmosis systems. In this research, flat ultrafiltration membranes (100, 50, 30 and 10 kDa) are used in a con- stant flux filtration mode to test and compare real seawaters from various locations (North and Mediterranean Sea) and from various full scale facilities including different pre-treatments (i.e., ultrafiltration and coagulation + dual media filtration). The operated fluxes range from 350 down to values close to real RO operation, 15l(m2h)-1. After each filtration test, the MFI-UF is calculated to assess the particulate fouling potential. The obtained results showed that: (1) the particulate and colloidal fouling potential is directly proportional to the applied flux during filtration. This proportionality is related to the compression of the cake deposit occurring at high flux values; (2) the higher the flux, the higher the required pressure, the less porous the cake and therefore the higher the specific cake resistance; (3) particulate and colloidal fouling potential of seawater is site specific and is influenced by pre-treatment. © 2012 Desalination Publications. All rights reserved.

  14. Characteristics of heat flux and particle flux to the divertor in H-mode of JT-60U

    International Nuclear Information System (INIS)

    Itami, K.; Hosogane, N.; Asakura, N.; Kubo, H.; Tsuji, S.; Shimada, M.

    1995-01-01

    Heat flux and particle flux behavior in H-mode is studied in a comparative manner. It was confirmed that the multiple peak structure of heat flux during ELM activity has a role in reducing the average value of a peak heat flux at the divertor. In order to characterize heat and particle flux during ELM activity, the ELM part and the steady state part of heat flux and particle flux were determined and statistically analyzed. A large in-out asymmetry of peak ELM heat flux density was found. The asymmetry is almost unaffected by the ion grad-B drift direction. In-out asymmetry of both ELM and steady-state parts of the particle flux were found to be similar. ((orig.))

  15. A model for heliospheric flux-ropes

    Science.gov (United States)

    Nieves-Chinchilla, T.; Linton, M.; Vourlidas, A.; Hidalgo, M. A. U.

    2017-12-01

    This work is presents an analytical flux-rope model, which explores different levels of complexity starting from a circular-cylindrical geometry. The framework of this series of models was established by Nieves-Chinchilla et al. 2016 with the circular-cylindrical analytical flux rope model. The model attempts to describe the magnetic flux rope topology with distorted cross-section as a possible consequence of the interaction with the solar wind. In this model, the flux rope is completely described in a non-orthogonal geometry. The Maxwell equations are solved using tensor calculus consistent with the geometry chosen, invariance along the axial direction, and with the assumption of no radial current density. The model is generalized in terms of the radial and azimuthal dependence of the poloidal current density component and axial current density component. The misalignment between current density and magnetic field is studied in detail for several example profiles of the axial and poloidal current density components. This theoretical analysis provides a map of the force distribution inside of the flux-rope. For reconstruction of the heliospheric flux-ropes, the circular-cylindrical reconstruction technique has been adapted to the new geometry and applied to in situ ICMEs with a flux-rope entrained and tested with cases with clear in situ signatures of distortion. The model adds a piece in the puzzle of the physical-analytical representation of these magnetic structures that should be evaluated with the ultimate goal of reconciling in-situ reconstructions with imaging 3D remote sensing CME reconstructions. Other effects such as axial curvature and/or expansion could be incorporated in the future to fully understand the magnetic structure.

  16. Communication: On the calculation of time-dependent electron flux within the Born-Oppenheimer approximation: A flux-flux reflection principle

    Science.gov (United States)

    Albert, Julian; Hader, Kilian; Engel, Volker

    2017-12-01

    It is commonly assumed that the time-dependent electron flux calculated within the Born-Oppenheimer (BO) approximation vanishes. This is not necessarily true if the flux is directly determined from the continuity equation obeyed by the electron density. This finding is illustrated for a one-dimensional model of coupled electronic-nuclear dynamics. There, the BO flux is in perfect agreement with the one calculated from a solution of the time-dependent Schrödinger equation for the coupled motion. A reflection principle is derived where the nuclear BO flux is mapped onto the electronic flux.

  17. Clustering of Emerging Flux

    Science.gov (United States)

    Ruzmaikin, A.

    1997-01-01

    Observations show that newly emerging flux tends to appear on the Solar surface at sites where there is flux already. This results in clustering of solar activity. Standard dynamo theories do not predict this effect.

  18. Predicting radon flux from uranium mill tailings

    International Nuclear Information System (INIS)

    Freeman, H.D.; Hartley, J.N.

    1983-11-01

    Pacific Northwest Laboratory (PNL), under contract to the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project (UMTRAP) office, is developing technology for the design of radon barriers for uranium mill tailings piles. To properly design a radon cover for a particular tailings pile, the radon flux emanating from the bare tailings must be known. The tailings characteristics required to calculate the radon flux include radium-226 content, emanating power, bulk density, and radon diffusivity. This paper presents theoretical and practical aspects of estimating the radon flux from an uranium tailings pile. Results of field measurements to verify the calculation methodology are also discussed. 24 references, 4 figures, 4 tables

  19. Eddy Correlation Flux Measurement System (ECOR) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Cook, DR

    2011-01-31

    The eddy correlation (ECOR) flux measurement system provides in situ, half-hour measurements of the surface turbulent fluxes of momentum, sensible heat, latent heat, and carbon dioxide (CO2) (and methane at one Southern Great Plains extended facility (SGP EF) and the North Slope of Alaska Central Facility (NSA CF). The fluxes are obtained with the eddy covariance technique, which involves correlation of the vertical wind component with the horizontal wind component, the air temperature, the water vapor density, and the CO2 concentration.

  20. Comparison of depth-averaged concentration and bed load flux sediment transport models of dam-break flow

    Directory of Open Access Journals (Sweden)

    Jia-heng Zhao

    2017-10-01

    Full Text Available This paper presents numerical simulations of dam-break flow over a movable bed. Two different mathematical models were compared: a fully coupled formulation of shallow water equations with erosion and deposition terms (a depth-averaged concentration flux model, and shallow water equations with a fully coupled Exner equation (a bed load flux model. Both models were discretized using the cell-centered finite volume method, and a second-order Godunov-type scheme was used to solve the equations. The numerical flux was calculated using a Harten, Lax, and van Leer approximate Riemann solver with the contact wave restored (HLLC. A novel slope source term treatment that considers the density change was introduced to the depth-averaged concentration flux model to obtain higher-order accuracy. A source term that accounts for the sediment flux was added to the bed load flux model to reflect the influence of sediment movement on the momentum of the water. In a one-dimensional test case, a sensitivity study on different model parameters was carried out. For the depth-averaged concentration flux model, Manning's coefficient and sediment porosity values showed an almost linear relationship with the bottom change, and for the bed load flux model, the sediment porosity was identified as the most sensitive parameter. The capabilities and limitations of both model concepts are demonstrated in a benchmark experimental test case dealing with dam-break flow over variable bed topography.

  1. Burnout in a channel with non-uniform circumferential heat flux

    International Nuclear Information System (INIS)

    Lee, D.H.

    1966-03-01

    Burnout experiments are reported for uniform flux and circumferential flux tilt (maximum/average flux about 1.25) with tubes and annuli, all the experiments having uniform axial heating. These show similar results, the burnout power with flux tilt being within 10% of that with uniform flux. For the same mean exit steam quality, the local maximum flux is higher than the predicted burnout value and generally a better prediction is obtained using the average flux. (author)

  2. Energy Conversion Loops for Flux-Switching PM Machine Analysis

    Directory of Open Access Journals (Sweden)

    E. Ilhan

    2012-10-01

    Full Text Available Induction and synchronous machines have traditionally been the first choice of automotive manufacturers for electric/hybrid vehicles. However, these conventional machines are not able anymore to meet the increasing demands for a higher energy density due to space limitation in cars. Flux-switching PM (FSPM machines with their high energy density are very suitable to answer this demand. In this paper, the energy conversion loop technique is implemented on FSPM for the first time. The energy conversion technique is a powerful tool for the visualization of machine characteristics, both linear and nonlinear. Further, the technique provides insight into the torque production mechanism. A stepwise explanation is given on how to create these loops for FSPM along with the machine operation.

  3. Impact of Te and ne on edge current density profiles in ELM mitigated regimes on ASDEX Upgrade

    Science.gov (United States)

    Dunne, M. G.; Rathgeber, S.; Burckhart, A.; Fischer, R.; Giannone, L.; McCarthy, P. J.; Schneider, P. A.; Wolfrum, E.; the ASDEX Upgrade Team

    2015-01-01

    ELM resolved edge current density profiles are reconstructed using the CLISTE equilibrium code. As input, highly spatially and temporally resolved edge electron temperature and density profiles are used in addition to data from the extensive set of external poloidal field measurements available at ASDEX Upgrade, flux loop difference measurements, and current measurements in the scrape-off layer. Both the local and flux surface averaged current density profiles are analysed for several ELM mitigation regimes. The focus throughout is on the impact of altered temperature and density profiles on the current density. In particular, many ELM mitigation regimes rely on operation at high density. Two reference plasmas with type-I ELMs are analysed, one with a deuterium gas puff and one without, in order to provide a reference for the behaviour in type-II ELMy regimes and high density ELM mitigation with external magnetic perturbations at ASDEX Upgrade. For type-II ELMs it is found that while a similar pedestal top pressure is sustained at the higher density, the temperature gradient decreases in the pedestal. This results in lower local and flux surface averaged current densities in these phases, which reduces the drive for the peeling mode. No significant differences between the current density measured in the type-I phase and ELM mitigated phase is seen when external perturbations are applied, though the pedestal top density was increased. Finally, ELMs during the nitrogen seeded phase of a high performance discharge are analysed and compared to ELMs in the reference phase. An increased pedestal pressure gradient, which is the source of confinement improvement in impurity seeded discharges, causes a local current density increase. However, the increased Zeff in the pedestal acts to reduce the flux surface averaged current density. This dichotomy, which is not observed in other mitigation regimes, could act to stabilize both the ballooning mode and the peeling mode at the

  4. Reducing Torque Ripples of the Axial Flux PM Motors by Magnet Stepping and Shifting

    Directory of Open Access Journals (Sweden)

    E. Cetin

    2018-02-01

    Full Text Available Higher efficiency on electric machines is the research goal of many studies. An example is the axial flux permanent magnet machines. These machines have some advantages like their watt/kg efficiency and torque density. This study aims to develop the performance characteristics of the axial flux permanent magnet machines. A new rotor magnet poles design in axial flux machines is suggested to mitigate the torque ripples. The method of stepping and shifting of the magnets is used. Two different designs are compared to verify the proposed approach. 3D finite element analysis is used for simulations. Torque ripple and back electromotive force waveforms are obtained from computer analysis. As a conclusion, the suggested method is found to be useable and mitigates the torque ripples. In addition to that, back EMF waveforms are turned to sinusoidal by the suggested design.

  5. FSFE: Fake Spectra Flux Extractor

    Science.gov (United States)

    Bird, Simeon

    2017-10-01

    The fake spectra flux extractor generates simulated quasar absorption spectra from a particle or adaptive mesh-based hydrodynamic simulation. It is implemented as a python module. It can produce both hydrogen and metal line spectra, if the simulation includes metals. The cloudy table for metal ionization fractions is included. Unlike earlier spectral generation codes, it produces absorption from each particle close to the sight-line individually, rather than first producing an average density in each spectral pixel, thus substantially preserving more of the small-scale velocity structure of the gas. The code supports both Gadget (ascl:0003.001) and AREPO.

  6. Multi-flux-tube system in the dual Ginzburg-Landau theory

    International Nuclear Information System (INIS)

    Ichie, H.; Suganuma, H.; Toki, H.

    1996-01-01

    We study the multi-flux-tube system in terms of the dual Ginzburg-Landau theory. We consider two periodic cases, where the directions of all the flux tubes are the same in one case and alternating in the other case for neighboring flux tubes. We formulate the multi-flux-tube system by regarding it as the system of two flux tubes penetrating through a two-dimensional spherical surface. We find the multi-flux-tube configuration becomes uniform above some critical flux-tube number density ρ c =1.3 endash 1.7 fm -2 . On the other hand, the inhomogeneity of the color electric distribution appears when the flux-tube density is smaller than ρ c . We study the inhomogeneity on the color electric distribution in relation with the flux-tube number density, and discuss the quark-gluon plasma formation process in ultrarelativistic heavy-ion collisions. copyright 1996 The American Physical Society

  7. 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

  8. Growth and solar energy conversion of Azolla sp., cultivated under four solar irradiance flux density; Crescimento e conversao da energia solar de Azolla sp. cultivada em quatro densidades do fluxo radiante

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, E.F. de [Acre Univ., Rio Branco, AC (Brazil); Lopes, N.F. [Vicosa Univ., MG (Brazil). Dept. de Biologia Vegetal

    1994-02-01

    Growth and solar energy conversion were studied in three Azolla species grown under four levels (30, 50, 70 and 100%) of solar radiation incidence under outdoor conditions. Under full sunlight, the specie A. microphylla showed higher crop growth rate, relative growth rate, net assimilation rate and efficiency of solar energy conversion than the other ones. (author). 8 figs., 23 refs.

  9. Characterization of ion fluxes and heat fluxes for PMI relevant conditions on Proto-MPEX

    Science.gov (United States)

    Beers, Clyde; Shaw, Guinevere; Biewer, Theodore; Rapp, Juergen

    2016-10-01

    Plasma characterization, in particular, particle flux and electron and ion temperature distributions nearest to an exposed target, are critical to quantifying Plasma Surface Interaction (PSI). In the Proto-Material Plasma Exposure eXperiment (Proto-MPEX), the ion fluxes and heat fluxes are derived from double Langmuir Probes (DLP) and Thomson Scattering in front of the target assuming Bohm conditions at the sheath entrance. Power fluxes derived from ne and Te measurements are compared to heat fluxes measured with IR thermography. The comparison will allow conclusions on the sheath heat transmission coefficient to be made experimentally. Different experimental conditions (low and high density plasmas (0.5 - 6 x 1019 m-3) with different magnetic configuration are compared. This work was supported by the U.S. D.O.E. contract DE-AC05-00OR22725.

  10. Crystal growth of emerald by flux method

    International Nuclear Information System (INIS)

    Inoue, Mikio; Narita, Eiichi; Okabe, Taijiro; Morishita, Toshihiko.

    1979-01-01

    Emerald crystals have been formed in two binary fluxes of Li 2 O-MoO 2 and Li 2 O-V 2 O 5 using the slow cooling method and the temperature gradient method under various conditions. In the flux of Li 2 O-MoO 3 carried out in the range of 2 -- 5 of molar ratios (MoO 3 /Li 2 O), emerald was crystallized in the temperature range from 750 to 950 0 C, and the suitable crystallization conditions were found to be the molar ratio of 3 -- 4 and the temperature about 900 0 C. In the flux of Li 2 O-V 2 O 5 carried out in the range of 1.7 -- 5 of molar ratios (V 2 O 5 /Li 2 O), emerald was crystallized in the temperature range from 900 to 1150 0 . The suitable crystals were obtained at the molar ratio of 3 and the temperature range of 1000 -- 1100 0 C. The crystallization temperature rised with an increase in the molar ratio of the both fluxes. The emeralds grown in two binary fluxes were transparent green, having the density of 2.68, the refractive index of 1.56, and the two distinct bands in the visible spectrum at 430 and 600nm. The emerald grown in Li 2 O-V 2 O 5 flux was more bluish green than that grown in Li 2 O-MoO 3 flux. The size of the spontaneously nucleated emerald grown in the former flux was larger than the latter, when crystallized by the slow cooling method. As for the solubility of beryl in the two fluxes, Li 2 O-V 2 O 5 flux was superior to Li 2 O-MoO 3 flux whose small solubility of SiO 2 caused an experimental problem to the temperature gradient method. The suitability of the two fluxes for the crystal growth of emerald by the flux method was discussed from the view point of various properties of above-mentioned two fluxes. (author)

  11. Road density

    Data.gov (United States)

    U.S. Environmental Protection Agency — Road density is generally highly correlated with amount of developed land cover. High road densities usually indicate high levels of ecological disturbance. More...

  12. Gap-related trapped magnetic flux dependence between single and combined bulk superconductors

    International Nuclear Information System (INIS)

    Deng, Z.; Miki, M.; Felder, B.; Tsuzuki, K.; Shinohara, N.; Uetake, T.; Izumi, M.

    2011-01-01

    Highlights: → Rectangular YBCO bulks to realize a compact combination. → The gap effect was added to consider in the trapped flux density mapping. → The trapped-flux dependence between single and combined bulks is gap related. → It is possible to estimate the total magnetic flux of bulk combinations. - Abstract: Aiming at examining the trapped-flux dependence between single and combined bulk superconductors for field-pole applications, three rectangular Y 1.65 Ba 2 Cu 3 O 7-x (YBCO) bulks with a possibly compact combination were employed to investigate the trapped-flux characteristics of single and combined bulks with a field-cooling magnetization (FCM) method. A gap-related dependence was found between them. At lower gaps of 1 mm and 5 mm, the peak trapped fields and total magnetic flux of combined bulks are both smaller than the additive values of each single bulk, which can be ascribed to the demagnetization influences of the field around the bulk generated by the adjacent ones. While, at larger gaps like 10 mm, the situation becomes reversed. The combined bulks can attain bigger peak trapped fields as well as total magnetic flux, which indicates that the magnetic field by the bulk combination can reach higher gaps, thanks to the bigger magnetic energy compared with the single bulk. The presented results show that, on one hand, it is possible to estimate the total trapped magnetic flux of combined bulks by an approximate additive method of each single bulk while considering a demagnetization factor; on the other hand, it also means that the performance of combined bulks will be superior to the addition of each single bulk at larger gaps, thus preferable for large-scaled magnet applications.

  13. Gap-related trapped magnetic flux dependence between single and combined bulk superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Z., E-mail: zgdeng@gmail.co [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, Tokyo 135-8533 (Japan); Miki, M.; Felder, B.; Tsuzuki, K.; Shinohara, N.; Uetake, T.; Izumi, M. [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, Tokyo 135-8533 (Japan)

    2011-05-15

    Highlights: {yields} Rectangular YBCO bulks to realize a compact combination. {yields} The gap effect was added to consider in the trapped flux density mapping. {yields} The trapped-flux dependence between single and combined bulks is gap related. {yields} It is possible to estimate the total magnetic flux of bulk combinations. - Abstract: Aiming at examining the trapped-flux dependence between single and combined bulk superconductors for field-pole applications, three rectangular Y{sub 1.65}Ba{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) bulks with a possibly compact combination were employed to investigate the trapped-flux characteristics of single and combined bulks with a field-cooling magnetization (FCM) method. A gap-related dependence was found between them. At lower gaps of 1 mm and 5 mm, the peak trapped fields and total magnetic flux of combined bulks are both smaller than the additive values of each single bulk, which can be ascribed to the demagnetization influences of the field around the bulk generated by the adjacent ones. While, at larger gaps like 10 mm, the situation becomes reversed. The combined bulks can attain bigger peak trapped fields as well as total magnetic flux, which indicates that the magnetic field by the bulk combination can reach higher gaps, thanks to the bigger magnetic energy compared with the single bulk. The presented results show that, on one hand, it is possible to estimate the total trapped magnetic flux of combined bulks by an approximate additive method of each single bulk while considering a demagnetization factor; on the other hand, it also means that the performance of combined bulks will be superior to the addition of each single bulk at larger gaps, thus preferable for large-scaled magnet applications.

  14. Generation mechanism of L-value dependence of oxygen flux enhancements during substorms

    Science.gov (United States)

    Nakayama, Y.; Ebihara, Y.; Tanaka, T.; Ohtani, S.; Gkioulidou, M.; Takahashi, K.; Kistler, L. M.; Kletzing, C.

    2015-12-01

    The Van Allen Probes Helium Oxygen Proton Electron (HOPE) instrument measures charged particles with an energy range from ~eV to ~ tens of keV. The observation shows that the energy flux of the particles increases inside the geosynchronous orbit during substorms. For some night-side events around the apogee, the energy flux of O+ ion enhances below ~10 keV at lower L shell, whereas the flux below ~8 keV sharply decreases at higher L shells. This structure of L-energy spectrogram of flux is observed only for the O+ ions. The purpose of this study is to investigate the generation mechanism of the structure by using numerical simulations. We utilized the global MHD simulation developed by Tanaka et al (2010, JGR) to simulate the electric and magnetic fields during substorms. We performed test particle simulation under the electric and magnetic fields by applying the same model introduced by Nakayama et al. (2015, JGR). In the test particle simulation each test particle carries the real number of particles in accordance with the Liouville theorem. Using the real number of particles, we reconstructed 6-dimensional phase space density and differential flux of O+ ions in the inner magnetosphere. We obtained the following results. (1) Just after the substorm onset, the dawn-to-dusk electric field is enhanced to ~ 20 mV/m in the night side tail region at L > 7. (2) The O+ ions are accelerated and transported to the inner region (L > ~5.5) by the large-amplitude electric field. (3) The reconstructed L-energy spectrogram shows a similar structure to the Van Allen Probes observation. (4) The difference in the flux enhancement between at lower L shell and higher L shells is due to two distinct acceleration processes: adiabatic and non-adiabatic. We will discuss the relationship between the particle acceleration and the structure of L-energy spectrogram of flux enhancement in detail.

  15. Primary cosmic ray flux

    Energy Technology Data Exchange (ETDEWEB)

    Stanev, Todor

    2001-05-01

    We discuss the primary cosmic ray flux from the point of view of particle interactions and production of atmospheric neutrinos. The overall normalization of the cosmic ray flux and its time variations and site dependence are major ingredients of the atmospheric neutrino predictions and the basis for the derivation of the neutrino oscillation parameters.

  16. Flux cutting in superconductors

    International Nuclear Information System (INIS)

    Campbell, A M

    2011-01-01

    This paper describes experiments and theories of flux cutting in superconductors. The use of the flux line picture in free space is discussed. In superconductors cutting can either be by means of flux at an angle to other layers of flux, as in longitudinal current experiments, or due to shearing of the vortex lattice as in grain boundaries in YBCO. Experiments on longitudinal currents can be interpreted in terms of flux rings penetrating axial lines. More physical models of flux cutting are discussed but all predict much larger flux cutting forces than are observed. Also, cutting is occurring at angles between vortices of about one millidegree which is hard to explain. The double critical state model and its developments are discussed in relation to experiments on crossed and rotating fields. A new experiment suggested by Clem gives more direct information. It shows that an elliptical yield surface of the critical state works well, but none of the theoretical proposals for determining the direction of E are universally applicable. It appears that, as soon as any flux flow takes place, cutting also occurs. The conclusion is that new theories are required. (perspective)

  17. Density control problems in large stellarators with neoclassical transport

    International Nuclear Information System (INIS)

    Maassberg, H.; Beidler, C.D.; Simmet, E.E.

    1999-01-01

    With respect to the particle flux, the off-diagonal term in the neoclassical transport matrix becomes crucial in the stellarator long-mean-free-path regime. Central heating with peaked temperature profiles can make an active density profile control by central particle refuelling mandatory. The neoclassical particle confinement can significantly exceed the energy confinement at the outer radii. As a consequence, the required central refuelling may be larger than the neoclassical particle fluxes at outer radii leading to the loss of the global density control. Radiative losses as well as additional 'anomalous' electron heat diffusivities further exacerbate this problem. In addition to the analytical formulation of the neoclassical link of particle and energy fluxes, simplified model simulations as well as time-dependent ASTRA code simulations are described. In particular, the 'low-' and 'high-mirror' W7-X configurations are compared. For the W7-X 'high-mirror' configuration especially, the appearance of the neoclassical particle transport barrier is predicted at higher densities. (author)

  18. Heat flux microsensor measurements

    Science.gov (United States)

    Terrell, J. P.; Hager, J. M.; Onishi, S.; Diller, T. E.

    1992-01-01

    A thin-film heat flux sensor has been fabricated on a stainless steel substrate. The thermocouple elements of the heat flux sensor were nickel and nichrome, and the temperature resistance sensor was platinum. The completed heat flux microsensor was calibrated at the AEDC radiation facility. The gage output was linear with heat flux with no apparent temperature effect on sensitivity. The gage was used for heat flux measurements at the NASA Langley Vitiated Air Test Facility. Vitiated air was expanded to Mach 3.0 and hydrogen fuel was injected. Measurements were made on the wall of a diverging duct downstream of the injector during all stages of the hydrogen combustion tests. Because the wall and the gage were not actively cooled, the wall temperature reached over 1000 C (1900 F) during the most severe test.

  19. Higher Education

    African Journals Online (AJOL)

    Kunle Amuwo: Higher Education Transformation: A Paradigm Shilt in South Africa? ... ty of such skills, especially at the middle management levels within the higher ... istics and virtues of differentiation and diversity. .... may be forced to close shop for lack of capacity to attract ..... necessarily lead to racial and gender equity,.

  20. THE TOPOLOGY OF CANONICAL FLUX TUBES IN FLARED JET GEOMETRY

    Energy Technology Data Exchange (ETDEWEB)

    Lavine, Eric Sander; You, Setthivoine, E-mail: Slavine2@uw.edu, E-mail: syou@aa.washington.edu [University of Washington, 4000 15th Street, NE Aeronautics and Astronautics 211 Guggenheim Hall, Box 352400, Seattle, WA 98195 (United States)

    2017-01-20

    Magnetized plasma jets are generally modeled as magnetic flux tubes filled with flowing plasma governed by magnetohydrodynamics (MHD). We outline here a more fundamental approach based on flux tubes of canonical vorticity, where canonical vorticity is defined as the circulation of the species’ canonical momentum. This approach extends the concept of magnetic flux tube evolution to include the effects of finite particle momentum and enables visualization of the topology of plasma jets in regimes beyond MHD. A flared, current-carrying magnetic flux tube in an ion-electron plasma with finite ion momentum is thus equivalent to either a pair of electron and ion flow flux tubes, a pair of electron and ion canonical momentum flux tubes, or a pair of electron and ion canonical vorticity flux tubes. We examine the morphology of all these flux tubes for increasing electrical currents, different radial current profiles, different electron Mach numbers, and a fixed, flared, axisymmetric magnetic geometry. Calculations of gauge-invariant relative canonical helicities track the evolution of magnetic, cross, and kinetic helicities in the system, and show that ion flow fields can unwind to compensate for an increasing magnetic twist. The results demonstrate that including a species’ finite momentum can result in a very long collimated canonical vorticity flux tube even if the magnetic flux tube is flared. With finite momentum, particle density gradients must be normal to canonical vorticities, not to magnetic fields, so observations of collimated astrophysical jets could be images of canonical vorticity flux tubes instead of magnetic flux tubes.

  1. Design and analysis of a flux intensifying permanent magnet embedded salient pole wind generator

    Science.gov (United States)

    Guo, Yujing; Jin, Ping; Lin, Heyun; Yang, Hui; Lyu, Shukang

    2018-05-01

    This paper presents an improved flux intensifying permanent magnet embedded salient pole wind generator (FI-PMESPWG) with mirror symmetrical magnetizing directions permanent magnet (PM) for improving generator's performances. The air-gap flux densities, the output voltage, the cogging torque and the d- and q-axis inductances of FI-PMESPWG are all calculated and analyzed by using the finite element method (FEM). To highlight the advantages of the proposed FI-PMESPWG, an original permanent magnet embedded salient pole wind generator (PMESPWG) model is adopted for comparison under the same operating conditions. The calculating results show that the air-gap flux densities of FI-PMESPWG are intensified with the same magnet amounts because the PMs are set in a form of V shape in each pole. The difference between d-axis inductance and q-axis inductance of the proposed FI-PMESPWG is reduced. Thus, the output power of the proposed FI-PMESPWG reaches a higher value than that of the original PMESPWG at the same current phase angle. The cogging torque is diminished because the flux path is changed. All the analysis results indicate that the electromagnetic characteristics of the proposed FI-PMESPWG are significantly better than that of the original PMESPWG.

  2. Higher Education

    Science.gov (United States)

    & Development (LDRD) National Security Education Center (NSEC) Office of Science Programs Richard P Databases National Security Education Center (NSEC) Center for Nonlinear Studies Engineering Institute Scholarships STEM Education Programs Teachers (K-12) Students (K-12) Higher Education Regional Education

  3. Eddy Correlation Flux Measurement System Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Cook, D. R. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-01-01

    The eddy correlation (ECOR) flux measurement system provides in situ, half-hour measurements of the surface turbulent fluxes of momentum, sensible heat, latent heat, and carbon dioxide (CO2) (and methane at one Southern Great Plains extended facility (SGP EF) and the North Slope of Alaska Central Facility (NSA CF). The fluxes are obtained with the eddy covariance technique, which involves correlation of the vertical wind component with the horizontal wind component, the air temperature, the water vapor density, and the CO2 concentration. The instruments used are: • a fast-response, three-dimensional (3D) wind sensor (sonic anemometer) to obtain the orthogonal wind components and the speed of sound (SOS) (used to derive the air temperature) • an open-path infrared gas analyzer (IRGA) to obtain the water vapor density and the CO2 concentration, and • an open-path infrared gas analyzer (IRGA) to obtain methane density and methane flux at one SGP EF and at the NSA CF. The ECOR systems are deployed at the locations where other methods for surface flux measurements (e.g., energy balance Bowen ratio [EBBR] systems) are difficult to employ, primarily at the north edge of a field of crops. A Surface Energy Balance System (SEBS) has been installed collocated with each deployed ECOR system in SGP, NSA, Tropical Western Pacific (TWP), ARM Mobile Facility 1 (AMF1), and ARM Mobile Facility 2 (AMF2). The surface energy balance system consists of upwelling and downwelling solar and infrared radiometers within one net radiometer, a wetness sensor, and soil measurements. The SEBS measurements allow the comparison of ECOR sensible and latent heat fluxes with the energy balance determined from the SEBS and provide information on wetting of the sensors for data quality purposes. The SEBS at one SGP and one NSA site also support upwelling and downwelling PAR measurements to qualify those two locations as Ameriflux sites.

  4. Lung density

    DEFF Research Database (Denmark)

    Garnett, E S; Webber, C E; Coates, G

    1977-01-01

    The density of a defined volume of the human lung can be measured in vivo by a new noninvasive technique. A beam of gamma-rays is directed at the lung and, by measuring the scattered gamma-rays, lung density is calculated. The density in the lower lobe of the right lung in normal man during quiet...... breathing in the sitting position ranged from 0.25 to 0.37 g.cm-3. Subnormal values were found in patients with emphsema. In patients with pulmonary congestion and edema, lung density values ranged from 0.33 to 0.93 g.cm-3. The lung density measurement correlated well with the findings in chest radiographs...... but the lung density values were more sensitive indices. This was particularly evident in serial observations of individual patients....

  5. Multidimensional flux-limited advection schemes

    International Nuclear Information System (INIS)

    Thuburn, J.

    1996-01-01

    A general method for building multidimensional shape preserving advection schemes using flux limiters is presented. The method works for advected passive scalars in either compressible or incompressible flow and on arbitrary grids. With a minor modification it can be applied to the equation for fluid density. Schemes using the simplest form of the flux limiter can cause distortion of the advected profile, particularly sideways spreading, depending on the orientation of the flow relative to the grid. This is partly because the simple limiter is too restrictive. However, some straightforward refinements lead to a shape-preserving scheme that gives satisfactory results, with negligible grid-flow angle-dependent distortion

  6. Flux pinning characteristics of YBCO coated conductor

    International Nuclear Information System (INIS)

    Matsushita, T.; Watanabe, T.; Fukumoto, Y.; Yamauchi, K.; Kiuchi, M.; Otabe, E.S.; Kiss, T.; Watanabe, T.; Miyata, S.; Ibi, A.; Muroga, T.; Yamada, Y.; Shiohara, Y.

    2005-01-01

    Flux pinning properties of PLD-processed YBCO coated conductors deposited on IBAD substrate are investigated. The thickness of YBCO layer is changed in the range of 0.27-1.0 μm. The thickness dependence of critical current density, n-value and irreversibility field are measured in a wide range of magnetic field. The results are compared with the theoretical flux creep-flow model. It is found that these pinning properties are strongly influenced by the thickness as well as the pinning strength. Optimum condition for high field application of this superconductor is discussed

  7. Higher order harmonics of reactor neutron equation

    International Nuclear Information System (INIS)

    Li Fu; Hu Yongming; Luo Zhengpei

    1996-01-01

    The flux mapping method using the higher order harmonics of the neutron equation is proposed. Based on the bi-orthogonality of the higher order harmonics, the process and formulas for higher order harmonics calculation are derived via the source iteration method with source correction. For the first time, not only any order harmonics for up-to-3-dimensional geometry are achieved, but also the preliminary verification to the capability for flux mapping have been carried out

  8. Soil greenhouse gas fluxes from different tree species on Taihang Mountain, North China

    Science.gov (United States)

    Liu, X. P.; Zhang, W. J.; Hu, C. S.; Tang, X. G.

    2014-03-01

    The objectives of this study were to investigate seasonal variation of greenhouse gas fluxes from soils on sites dominated by plantation (Robinia pseudoacacia, Punica granatum, and Ziziphus jujube) and natural regenerated forests (Vitex negundo var. heterophylla, Leptodermis oblonga, and Bothriochloa ischcemum), and to identify how tree species, litter exclusion, and soil properties (soil temperature, soil moisture, soil organic carbon, total N, soil bulk density, and soil pH) explained the temporal and spatial variation in soil greenhouse gas fluxes. Fluxes of greenhouse gases were measured using static chamber and gas chromatography techniques. Six static chambers were randomly installed in each tree species. Three chambers were randomly designated to measure the impacts of surface litter exclusion, and the remaining three were used as a control. Field measurements were conducted biweekly from May 2010 to April 2012. Soil CO2 emissions from all tree species were significantly affected by soil temperature, soil moisture, and their interaction. Driven by the seasonality of temperature and precipitation, soil CO2 emissions demonstrated a clear seasonal pattern, with fluxes significantly higher during the rainy season than during the dry season. Soil CH4 and N2O fluxes were not significantly correlated with soil temperature, soil moisture, or their interaction, and no significant seasonal differences were detected. Soil organic carbon and total N were significantly positively correlated with CO2 and N2O fluxes. Soil bulk density was significantly negatively correlated with CO2 and N2O fluxes. Soil pH was not correlated with CO2 and N2O emissions. Soil CH4 fluxes did not display pronounced dependency on soil organic carbon, total N, soil bulk density, and soil pH. Removal of surface litter significantly decreased in CO2 emissions and CH4 uptakes. Soils in six tree species acted as sinks for atmospheric CH4. With the exception of Ziziphus jujube, soils in all tree

  9. Flux in Tallinn

    Index Scriptorium Estoniae

    2004-01-01

    Rahvusvahelise elektroonilise kunsti sümpoosioni ISEA2004 klubiõhtu "Flux in Tallinn" klubis Bon Bon. Eestit esindasid Ropotator, Ars Intel Inc., Urmas Puhkan, Joel Tammik, Taavi Tulev (pseud. Wochtzchee). Klubiõhtu koordinaator Andres Lõo

  10. Flux shunts for undulators

    International Nuclear Information System (INIS)

    Hoyer, E.; Chin, J.; Hassenzahl, W.V.

    1993-05-01

    Undulators for high-performance applications in synchrotron-radiation sources and periodic magnetic structures for free-electron lasers have stringent requirements on the curvature of the electron's average trajectory. Undulators using the permanent magnet hybrid configuration often have fields in their central region that produce a curved trajectory caused by local, ambient magnetic fields such as those of the earth. The 4.6 m long Advanced Light Source (ALS) undulators use flux shunts to reduce this effect. These flux shunts are magnetic linkages of very high permeability material connecting the two steel beams that support the magnetic structures. The shunts reduce the scalar potential difference between the supporting beams and carry substantial flux that would normally appear in the undulator gap. Magnetic design, mechanical configuration of the flux shunts and magnetic measurements of their effect on the ALS undulators are described

  11. Design Considerations of Permanent Magnet Transverse Flux Machines

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Rasmussen, Peter Omand; Ritchie, Ewen

    2011-01-01

    electrical machines. This paper addresses two important design considerations for PMTFM—the influence of permanent magnet leakage flux, which plays an important role in the determination of machine output torque, and the leakage inductance. A new simple method to provide a quick estimation of the armature......Permanent magnet transverse flux machine (PMTFM) is well known for its high torque density and is interested in various direct-drive applications. Due to its complicated 3-D flux components, design and design optimization of a PMTFM is more difficult and time consuming than for radial flux...

  12. Neutron flux monitor

    International Nuclear Information System (INIS)

    Oda, Naotaka.

    1993-01-01

    The device of the present invention greatly saves an analog processing section such as an analog filter and an analog processing circuit. That is, the device of the present invention comprises (1) a neutron flux detection means for detecting neutron fluxed in the reactor, (2) a digital filter means for dividing signals corresponding to the detected neutron fluxes into predetermined frequency band regions, (3) a calculation processing means for applying a calculation processing corresponding to the frequency band regions to the neutron flux detection signals divided by the digital filter means. With such a constitution, since the neutron detection signals are processed by the digital filter means, the accuracy is improved and the change for the property of the filter is facilitated. Further, when a neutron flux level is obtained, a calculation processing corresponding to the frequency band region can be conducted without the analog processing circuit. Accordingly, maintenance and accuracy are improved by greatly decreasing the number of parts. Further, since problems inherent to the analog circuit are solved, neutron fluxes are monitored at high reliability. (I.S.)

  13. The influence of humidity fluxes on offshore wind speed profiles

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Sempreviva, Anna Maria; Pryor, Sara

    2010-01-01

    extrapolation from lower measurements. With humid conditions and low mechanical turbulence offshore, deviations from the traditional logarithmic wind speed profile become significant and stability corrections are required. This research focuses on quantifying the effect of humidity fluxes on stability corrected...... wind speed profiles. The effect on wind speed profiles is found to be important in stable conditions where including humidity fluxes forces conditions towards neutral. Our results show that excluding humidity fluxes leads to average predicted wind speeds at 150 m from 10 m which are up to 4% higher...... than if humidity fluxes are included, and the results are not very sensitive to the method selected to estimate humidity fluxes....

  14. Higher Education.

    Science.gov (United States)

    Hendrickson, Robert M.

    This chapter reports 1982 cases involving aspects of higher education. Interesting cases noted dealt with the federal government's authority to regulate state employees' retirement and raised the questions of whether Title IX covers employment, whether financial aid makes a college a program under Title IX, and whether sex segregated mortality…

  15. Circulating levels of dickkopf-1, osteoprotegerin and sclerostin are higher in old compared with young men and women and positively associated with whole-body bone mineral density in older adults

    NARCIS (Netherlands)

    Coulson, J.; Bagley, L.; Barnouin, Y.; Bradburn, S.; Butler-Browne, G.; Gapeyeva, H.; Hogrel, J. Y.; Maden-Wilkinson, T.; Maier, A. B.; Meskers, C.; Murgatroyd, C.; Narici, M.; Pääsuke, M.; Sassano, L.; Sipilä, S.; Al-Shanti, N.; Stenroth, L.; Jones, D. A.; McPhee, J. S.

    2017-01-01

    Summary: Bone mineral density declines with increasing older age. We examined the levels of circulating factors known to regulate bone metabolism in healthy young and older adults. The circulating levels of dickkopf-1, osteocalcin, osteoprotegerin and sclerostin were positively associated with

  16. Framework for Flux Qubit Design

    Science.gov (United States)

    Yan, Fei; Kamal, Archana; Krantz, Philip; Campbell, Daniel; Kim, David; Yoder, Jonilyn; Orlando, Terry; Gustavsson, Simon; Oliver, William; Engineering Quantum Systems Team

    A qubit design for higher performance relies on the understanding of how various qubit properties are related to design parameters. We construct a framework for understanding the qubit design in the flux regime. We explore different parameter regimes, looking for features desirable for certain purpose in the context of quantum computing. This research was funded by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA) via MIT Lincoln Laboratory under Air Force Contract No. FA8721-05-C-0002.

  17. Theory of flux cutting and flux transport at the critical current of a type-II superconducting cylindrical wire

    International Nuclear Information System (INIS)

    Clem, John R.

    2011-01-01

    I introduce a critical-state theory incorporating both flux cutting and flux transport to calculate the magnetic-field and current-density distributions inside a type-II superconducting cylinder at its critical current in a longitudinal applied magnetic field. The theory is an extension of the elliptic critical-state model introduced by Romero-Salazar and Perez-Rodriguez. The vortex dynamics depend in detail on two nonlinear effective resistivities for flux cutting (ρ(parallel)) and flux flow (ρ(perpendicular)), and their ratio r = ρ(parallel)/ρ(perpendicular). When r c (φ) that makes the vortex arc unstable.

  18. Local particle flux reversal under strongly sheared flow

    International Nuclear Information System (INIS)

    Terry, P.W.; Newman, D.E.; Ware, A.S.

    2003-01-01

    The advection of electron density by turbulent ExB flow with linearly varying mean yields a particle flux that can reverse sign at certain locations along the direction of magnetic shear. The effect, calculated for strong flow shear, resides in the density-potential cross phase. It is produced by the interplay between the inhomogeneities of magnetic shear and flow shear, but subject to a variety of conditions and constraints. The regions of reversed flux tend to wash out if the turbulence consists of closely spaced modes of different helicities, but survive if modes of a single helicity are relatively isolated. The reversed flux becomes negligible if the electron density response is governed by electron scales while the eigenmode is governed by ion scales. The relationship of these results to experimentally observe flux reversals is discussed

  19. Rotating flux compressor for energy conversion

    International Nuclear Information System (INIS)

    Chowdhuri, P.; Linton, T.W.; Phillips, J.A.

    1983-01-01

    The rotating flux compressor (RFC) converts rotational kinetic energy into an electrical output pulse which would have higher energy than the electrical energy initially stored in the compressor. An RFC has been designed in which wedge-shaped rotor blades pass through the air gaps between successive turns of a solenoid, the stator. Magnetic flux is generated by pulsing the stator solenoids when the inductance is a maximum, i.e., when the flux fills the stator-solenoid volume. Connecting the solenoid across a load conserves the flux which is compressed within the small volume surrounding the stator periphery when the rotor blades cut into the free space between the stator plates, creating a minimum-inductance condition. The unique features of this design are: (1) no electrical connections (brushes) to the rotor; (2) no conventional windings; and (3) no maintenance. The device has been tested up to 5000 rpm of rotor speed

  20. The Open Flux Problem

    Science.gov (United States)

    Linker, J. A.; Caplan, R. M.; Downs, C.; Riley, P.; Mikic, Z.; Lionello, R.; Henney, C. J.; Arge, C. N.; Liu, Y.; Derosa, M. L.; Yeates, A.; Owens, M. J.

    2017-10-01

    The heliospheric magnetic field is of pivotal importance in solar and space physics. The field is rooted in the Sun’s photosphere, where it has been observed for many years. Global maps of the solar magnetic field based on full-disk magnetograms are commonly used as boundary conditions for coronal and solar wind models. Two primary observational constraints on the models are (1) the open field regions in the model should approximately correspond to coronal holes (CHs) observed in emission and (2) the magnitude of the open magnetic flux in the model should match that inferred from in situ spacecraft measurements. In this study, we calculate both magnetohydrodynamic and potential field source surface solutions using 14 different magnetic maps produced from five different types of observatory magnetograms, for the time period surrounding 2010 July. We have found that for all of the model/map combinations, models that have CH areas close to observations underestimate the interplanetary magnetic flux, or, conversely, for models to match the interplanetary flux, the modeled open field regions are larger than CHs observed in EUV emission. In an alternative approach, we estimate the open magnetic flux entirely from solar observations by combining automatically detected CHs for Carrington rotation 2098 with observatory synoptic magnetic maps. This approach also underestimates the interplanetary magnetic flux. Our results imply that either typical observatory maps underestimate the Sun’s magnetic flux, or a significant portion of the open magnetic flux is not rooted in regions that are obviously dark in EUV and X-ray emission.

  1. The Open Flux Problem

    Energy Technology Data Exchange (ETDEWEB)

    Linker, J. A.; Caplan, R. M.; Downs, C.; Riley, P.; Mikic, Z.; Lionello, R. [Predictive Science Inc., 9990 Mesa Rim Road, Suite 170, San Diego, CA 92121 (United States); Henney, C. J. [Air Force Research Lab/Space Vehicles Directorate, 3550 Aberdeen Avenue SE, Kirtland AFB, NM (United States); Arge, C. N. [Science and Exploration Directorate, NASA/GSFC, Greenbelt, MD 20771 (United States); Liu, Y. [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States); Derosa, M. L. [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street B/252, Palo Alto, CA 94304 (United States); Yeates, A. [Department of Mathematical Sciences, Durham University, Durham, DH1 3LE (United Kingdom); Owens, M. J., E-mail: linkerj@predsci.com [Space and Atmospheric Electricity Group, Department of Meteorology, University of Reading, Earley Gate, P.O. Box 243, Reading RG6 6BB (United Kingdom)

    2017-10-10

    The heliospheric magnetic field is of pivotal importance in solar and space physics. The field is rooted in the Sun’s photosphere, where it has been observed for many years. Global maps of the solar magnetic field based on full-disk magnetograms are commonly used as boundary conditions for coronal and solar wind models. Two primary observational constraints on the models are (1) the open field regions in the model should approximately correspond to coronal holes (CHs) observed in emission and (2) the magnitude of the open magnetic flux in the model should match that inferred from in situ spacecraft measurements. In this study, we calculate both magnetohydrodynamic and potential field source surface solutions using 14 different magnetic maps produced from five different types of observatory magnetograms, for the time period surrounding 2010 July. We have found that for all of the model/map combinations, models that have CH areas close to observations underestimate the interplanetary magnetic flux, or, conversely, for models to match the interplanetary flux, the modeled open field regions are larger than CHs observed in EUV emission. In an alternative approach, we estimate the open magnetic flux entirely from solar observations by combining automatically detected CHs for Carrington rotation 2098 with observatory synoptic magnetic maps. This approach also underestimates the interplanetary magnetic flux. Our results imply that either typical observatory maps underestimate the Sun’s magnetic flux, or a significant portion of the open magnetic flux is not rooted in regions that are obviously dark in EUV and X-ray emission.

  2. Hamiltonian boundary term and quasilocal energy flux

    International Nuclear Information System (INIS)

    Chen, C.-M.; Nester, James M.; Tung, R.-S.

    2005-01-01

    The Hamiltonian for a gravitating region includes a boundary term which determines not only the quasilocal values but also, via the boundary variation principle, the boundary conditions. Using our covariant Hamiltonian formalism, we found four particular quasilocal energy-momentum boundary term expressions; each corresponds to a physically distinct and geometrically clear boundary condition. Here, from a consideration of the asymptotics, we show how a fundamental Hamiltonian identity naturally leads to the associated quasilocal energy flux expressions. For electromagnetism one of the four is distinguished: the only one which is gauge invariant; it gives the familiar energy density and Poynting flux. For Einstein's general relativity two different boundary condition choices correspond to quasilocal expressions which asymptotically give the ADM energy, the Trautman-Bondi energy and, moreover, an associated energy flux (both outgoing and incoming). Again there is a distinguished expression: the one which is covariant

  3. A novel single-phase flux-switching permanent magnet linear generator used for free-piston Stirling engine

    Science.gov (United States)

    Zheng, Ping; Sui, Yi; Tong, Chengde; Bai, Jingang; Yu, Bin; Lin, Fei

    2014-05-01

    This paper investigates a novel single-phase flux-switching permanent-magnet (PM) linear machine used for free-piston Stirling engines. The machine topology and operating principle are studied. A flux-switching PM linear machine is designed based on the quasi-sinusoidal speed characteristic of the resonant piston. Considering the performance of back electromotive force and thrust capability, some leading structural parameters, including the air gap length, the PM thickness, the ratio of the outer radius of mover to that of stator, the mover tooth width, the stator tooth width, etc., are optimized by finite element analysis. Compared with conventional three-phase moving-magnet linear machine, the proposed single-phase flux-switching topology shows advantages in less PM use, lighter mover, and higher volume power density.

  4. Meromorphic flux compactification

    Energy Technology Data Exchange (ETDEWEB)

    Damian, Cesar [Departamento de Ingeniería Mecánica, Universidad de Guanajuato,Carretera Salamanca-Valle de Santiago Km 3.5+1.8 Comunidad de Palo Blanco,Salamanca (Mexico); Loaiza-Brito, Oscar [Departamento de Física, Universidad de Guanajuato,Loma del Bosque No. 103 Col. Lomas del Campestre C.P 37150 León, Guanajuato (Mexico)

    2017-04-26

    We present exact solutions of four-dimensional Einstein’s equations related to Minkoswki vacuum constructed from Type IIB string theory with non-trivial fluxes. Following https://www.doi.org/10.1007/JHEP02(2015)187; https://www.doi.org/10.1007/JHEP02(2015)188 we study a non-trivial flux compactification on a fibered product by a four-dimensional torus and a two-dimensional sphere punctured by 5- and 7-branes. By considering only 3-form fluxes and the dilaton, as functions on the internal sphere coordinates, we show that these solutions correspond to a family of supersymmetric solutions constructed by the use of G-theory. Meromorphicity on functions constructed in terms of fluxes and warping factors guarantees that flux and 5-brane contributions to the scalar curvature vanish while fulfilling stringent constraints as tadpole cancelation and Bianchi identities. Different Einstein’s solutions are shown to be related by U-dualities. We present three supersymmetric non-trivial Minkowski vacuum solutions and compute the corresponding soft terms. We also construct a non-supersymmetric solution and study its stability.

  5. Meromorphic flux compactification

    International Nuclear Information System (INIS)

    Damian, Cesar; Loaiza-Brito, Oscar

    2017-01-01

    We present exact solutions of four-dimensional Einstein’s equations related to Minkoswki vacuum constructed from Type IIB string theory with non-trivial fluxes. Following https://www.doi.org/10.1007/JHEP02(2015)187; https://www.doi.org/10.1007/JHEP02(2015)188 we study a non-trivial flux compactification on a fibered product by a four-dimensional torus and a two-dimensional sphere punctured by 5- and 7-branes. By considering only 3-form fluxes and the dilaton, as functions on the internal sphere coordinates, we show that these solutions correspond to a family of supersymmetric solutions constructed by the use of G-theory. Meromorphicity on functions constructed in terms of fluxes and warping factors guarantees that flux and 5-brane contributions to the scalar curvature vanish while fulfilling stringent constraints as tadpole cancelation and Bianchi identities. Different Einstein’s solutions are shown to be related by U-dualities. We present three supersymmetric non-trivial Minkowski vacuum solutions and compute the corresponding soft terms. We also construct a non-supersymmetric solution and study its stability.

  6. Analysis of flux reduction behaviors of PRO hollow fiber membranes: Experiments, mechanisms, and implications

    KAUST Repository

    Xiong, Jun Ying; Cheng, Zhen Lei; Wan, Chun Feng; Chen, Si Cong; Chung, Neal Tai-Shung

    2016-01-01

    in various behaviours of external performance indexes such as water flux, reverse salt flux, and power density. Then, the research is extended to investigate the effects of the growing bulk feed salinity due to the accumulated reverse salt flux along PRO

  7. Heat Flux of a Transferred Arc Driven by a Transverse Magnetic Field

    Directory of Open Access Journals (Sweden)

    Naomi Matsumoto

    2009-01-01

    Full Text Available Theoretical consideration of a magnetically driven arc was performed to elucidate the variation of heat flux with an imposed DC magnetic field. Experiments were conducted to confirm the validity of the theoretical model. The heat flux decreased concomitantly with increased imposed magnetic flux density. Theoretical predictions agreed with experimental results.

  8. Low Bone Density

    Science.gov (United States)

    ... Density Exam/Testing › Low Bone Density Low Bone Density Low bone density is when your bone density ... people with normal bone density. Detecting Low Bone Density A bone density test will determine whether you ...

  9. Neutron flux monitoring device

    International Nuclear Information System (INIS)

    Goto, Yasushi; Mitsubori, Minehisa; Ohashi, Kazunori.

    1997-01-01

    The present invention provides a neutron flux monitoring device for preventing occurrence of erroneous reactor scram caused by the elevation of the indication of a start region monitor (SRM) due to a factor different from actual increase of neutron fluxes. Namely, judgement based on measured values obtained by a pulse counting method and a judgment based on measured values obtained by a Cambel method are combined. A logic of switching neutron flux measuring method to be used for monitoring, namely, switching to an intermediate region when both of the judgements are valid is adopted. Then, even if the indication value is elevated based on the Cambel method with no increase of the counter rate in a neutron source region, the switching to the intermediate region is not conducted. As a result, erroneous reactor scram such as 'shorter reactor period' can be avoided. (I.S.)

  10. Apex Dips of Experimental Flux Ropes: Helix or Cusp?

    Energy Technology Data Exchange (ETDEWEB)

    Wongwaitayakornkul, Pakorn; Haw, Magnus A.; Bellan, Paul M. [Applied Physics, California Institute of Technology, Pasadena, CA 91125 (United States); Li, Hui [Theoretical Division, Los Alamos National Laboratory, Mail Stop B227, Los Alamos, NM 87545 (United States); Li, Shengtai, E-mail: pwongwai@caltech.edu, E-mail: mhaw@caltech.edu [Mathematical Modeling and Analysis, Los Alamos National Laboratory, Mail Stop B284, Los Alamos, NM 87545 (United States)

    2017-10-20

    We present a new theory for the presence of apex dips in certain experimental flux ropes. Previously such dips were thought to be projections of a helical loop axis generated by the kink instability. However, new evidence from experiments and simulations suggest that the feature is a 2D cusp rather than a 3D helix. The proposed mechanism for cusp formation is a density pileup region generated by nonlinear interaction of neutral gas cones emitted from fast-gas nozzles. The results indicate that density perturbations can result in large distortions of an erupting flux rope, even in the absence of significant pressure or gravitational forces. The density pileup at the apex also suppresses the m = 1 kink mode by acting as a stationary node. Consequently, more accurate density profiles should be considered when attempting to model the stability and shape of solar and astrophysical flux ropes.

  11. Correlation between the Flux Density and Polarization for Flat ...

    Indian Academy of Sciences (India)

    3Guangzhou Vocational College of Technology & Business, Guangzhou, China. ... model (Urry & Padovani 1995), in which there is a supermassive black hole at ... This work is partially supported by the National Natural Science Foundation of.

  12. Atmospheric neutrino fluxes

    International Nuclear Information System (INIS)

    Honda, M.; Kasahara, K.; Hidaka, K.; Midorikawa, S.

    1990-02-01

    A detailed Monte Carlo simulation of neutrino fluxes of atmospheric origin is made taking into account the muon polarization effect on neutrinos from muon decay. We calculate the fluxes with energies above 3 MeV for future experiments. There still remains a significant discrepancy between the calculated (ν e +antiν e )/(ν μ +antiν μ ) ratio and that observed by the Kamiokande group. However, the ratio evaluated at the Frejus site shows a good agreement with the data. (author)

  13. MAGNETIC FLUX EXPULSION IN STAR FORMATION

    International Nuclear Information System (INIS)

    Zhao Bo; Li Zhiyun; Nakamura, Fumitaka; Krasnopolsky, Ruben; Shang, Hsien

    2011-01-01

    Stars form in dense cores of magnetized molecular clouds. If the magnetic flux threading the cores is dragged into the stars, the stellar field would be orders of magnitude stronger than observed. This well-known 'magnetic flux problem' demands that most of the core magnetic flux be decoupled from the matter that enters the star. We carry out the first exploration of what happens to the decoupled magnetic flux in three dimensions, using a magnetohydrodynamic (MHD) version of the ENZO adaptive mesh refinement code. The field-matter decoupling is achieved through a sink particle treatment, which is needed to follow the protostellar accretion phase of star formation. We find that the accumulation of the decoupled flux near the accreting protostar leads to a magnetic pressure buildup. The high pressure is released anisotropically along the path of least resistance. It drives a low-density expanding region in which the decoupled magnetic flux is expelled. This decoupling-enabled magnetic structure has never been seen before in three-dimensional MHD simulations of star formation. It generates a strong asymmetry in the protostellar accretion flow, potentially giving a kick to the star. In the presence of an initial core rotation, the structure presents an obstacle to the formation of a rotationally supported disk, in addition to magnetic braking, by acting as a rigid magnetic wall that prevents the rotating gas from completing a full orbit around the central object. We conclude that the decoupled magnetic flux from the stellar matter can strongly affect the protostellar collapse dynamics.

  14. Flux Cancellation Leading to CME Filament Eruptions

    Science.gov (United States)

    Popescu, Roxana M.; Panesar, Navdeep K.; Sterling, Alphonse C.; Moore, Ronald L.

    2016-01-01

    Solar filaments are strands of relatively cool, dense plasma magnetically suspended in the lower density hotter solar corona. They trace magnetic polarity inversion lines (PILs) in the photosphere below, and are supported against gravity at heights of up to approx.100 Mm above the chromosphere by the magnetic field in and around them. This field erupts when it is rendered unstable, often by magnetic flux cancellation or emergence at or near the PIL. We have studied the evolution of photospheric magnetic flux leading to ten observed filament eruptions. Specifically, we look for gradual magnetic changes in the neighborhood of the PIL prior to and during eruption. We use Extreme Ultraviolet (EUV) images from the Atmospheric Imaging Assembly (AIA), and magnetograms from the Helioseismic and Magnetic Imager (HMI), both on board the Solar Dynamics Observatory (SDO), to study filament eruptions and their photospheric magnetic fields. We examine whether flux cancellation or/and emergence leads to filament eruptions. We find that continuous flux cancellation was present at the PIL for many hours prior to each eruption. We present two CME-producing eruptions in detail and find the following: (a) the pre-eruption filament-holding core field is highly sheared and appears in the shape of a sigmoid above the PIL; (b) at the start of the eruption the opposite arms of the sigmoid reconnect in the middle above the site of (tether-cutting) flux cancellation at the PIL; (c) the filaments first show a slow-rise, followed by a fast-rise as they erupt. We conclude that these two filament eruptions result from flux cancellation in the middle of the sheared field, and thereafter evolve in agreement with the standard model for a CME/flare filament eruption from a closed bipolar magnetic field [flux cancellation (van Ballegooijen and Martens 1989 and Moore and Roumelrotis 1992) and runaway tether-cutting (Moore et. al 2001)].

  15. 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.)

  16. Average fast neutron flux in three energy ranges in the Quinta assembly irradiated by two types of beams

    Directory of Open Access Journals (Sweden)

    Strugalska-Gola Elzbieta

    2017-01-01

    Full Text Available This work was performed within the international project “Energy plus Transmutation of Radioactive Wastes” (E&T - RAW for investigations of energy production and transmutation of radioactive waste of the nuclear power industry. 89Y (Yttrium 89 samples were located in the Quinta assembly in order to measure an average high neutron flux density in three different energy ranges using deuteron and proton beams from Dubna accelerators. Our analysis showed that the neutron density flux for the neutron energy range 20.8 - 32.7 MeV is higher than for the neutron energy range 11.5 - 20.8 MeV both for protons with an energy of 0.66 GeV and deuterons with an energy of 2 GeV, while for deuteron beams of 4 and 6 GeV we did not observe this.

  17. Magnetic studies of current conduction and flux pinning in high-Tc cuprates: Virgin, irradiated, and oxygen deficient materials

    International Nuclear Information System (INIS)

    Thompson, J.R.; Civale, L.; Marwick, A.D.; Holtzberg, F.

    1992-09-01

    To increase the current density and pinning of magnetic flux in high temperature superconductors, defects with point-like and line-like geometries were created in controlled numbers using ion irradiation methods. Single crystals of Y 1 Ba 2 Cu 3 O 7 and Bi 2 Sr 2 Ca 1 Cu 2 0 8 superconductors were studied using dc magnetic methods. These studies showed greatly increased irreversibility in the vortex state magnetization and enhanced intragrain current density J c following irradiation. Linear defects, created by irradiation with energetic heavy ions, are particularly effective in pinning vortices at higher temperatures and magnetic fields. Further investigations of ''flux creep'' (the time dependence of magnetization) are well described by recent vortex glass and collective pinning theories. Complementary investigations have delineated the role of oxygen deficiency δ on pinning in aligned Y 1 Ba 2 Cu 3 O 7-δ materials

  18. The role of riparian vegetation density, channel orientation and water velocity in determining river temperature dynamics

    Science.gov (United States)

    Garner, Grace; Malcolm, Iain A.; Sadler, Jonathan P.; Hannah, David M.

    2017-10-01

    A simulation experiment was used to understand the importance of riparian vegetation density, channel orientation and flow velocity for stream energy budgets and river temperature dynamics. Water temperature and meteorological observations were obtained in addition to hemispherical photographs along a ∼1 km reach of the Girnock Burn, a tributary of the Aberdeenshire Dee, Scotland. Data from nine hemispherical images (representing different uniform canopy density scenarios) were used to parameterise a deterministic net radiation model and simulate radiative fluxes. For each vegetation scenario, the effects of eight channel orientations were investigated by changing the position of north at 45° intervals in each hemispheric image. Simulated radiative fluxes and observed turbulent fluxes drove a high-resolution water temperature model of the reach. Simulations were performed under low and high water velocity scenarios. Both velocity scenarios yielded decreases in mean (≥1.6 °C) and maximum (≥3.0 °C) temperature as canopy density increased. Slow-flowing water resided longer within the reach, which enhanced heat accumulation and dissipation, and drove higher maximum and lower minimum temperatures. Intermediate levels of shade produced highly variable energy flux and water temperature dynamics depending on the channel orientation and thus the time of day when the channel was shaded. We demonstrate that in many reaches relatively sparse but strategically located vegetation could produce substantial reductions in maximum temperature and suggest that these criteria are used to inform future river management.

  19. 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.

  20. A finite element calculation of flux pumping

    Science.gov (United States)

    Campbell, A. M.

    2017-12-01

    A flux pump is not only a fascinating example of the power of Faraday’s concept of flux lines, but also an attractive way of powering superconducting magnets without large electronic power supplies. However it is not possible to do this in HTS by driving a part of the superconductor normal, it must be done by exceeding the local critical density. The picture of a magnet pulling flux lines through the material is attractive, but as there is no direct contact between flux lines in the magnet and vortices, unless the gap between them is comparable to the coherence length, the process must be explicable in terms of classical electromagnetism and a nonlinear V-I characteristic. In this paper a simple 2D model of a flux pump is used to determine the pumping behaviour from first principles and the geometry. It is analysed with finite element software using the A formulation and FlexPDE. A thin magnet is passed across one or more superconductors connected to a load, which is a large rectangular loop. This means that the self and mutual inductances can be calculated explicitly. A wide strip, a narrow strip and two conductors are considered. Also an analytic circuit model is analysed. In all cases the critical state model is used, so the flux flow resistivity and dynamic resistivity are not directly involved, although an effective resistivity appears when J c is exceeded. In most of the cases considered here is a large gap between the theory and the experiments. In particular the maximum flux transferred to the load area is always less than the flux of the magnet. Also once the threshold needed for pumping is exceeded the flux in the load saturates within a few cycles. However the analytic circuit model allows a simple modification to allow for the large reduction in I c when the magnet is over a conductor. This not only changes the direction of the pumped flux but leads to much more effective pumping.

  1. Level densities

    International Nuclear Information System (INIS)

    Ignatyuk, A.V.

    1998-01-01

    For any applications of the statistical theory of nuclear reactions it is very important to obtain the parameters of the level density description from the reliable experimental data. The cumulative numbers of low-lying levels and the average spacings between neutron resonances are usually used as such data. The level density parameters fitted to such data are compiled in the RIPL Starter File for the tree models most frequently used in practical calculations: i) For the Gilber-Cameron model the parameters of the Beijing group, based on a rather recent compilations of the neutron resonance and low-lying level densities and included into the beijing-gc.dat file, are chosen as recommended. As alternative versions the parameters provided by other groups are given into the files: jaeri-gc.dat, bombay-gc.dat, obninsk-gc.dat. Additionally the iljinov-gc.dat, and mengoni-gc.dat files include sets of the level density parameters that take into account the damping of shell effects at high energies. ii) For the backed-shifted Fermi gas model the beijing-bs.dat file is selected as the recommended one. Alternative parameters of the Obninsk group are given in the obninsk-bs.dat file and those of Bombay in bombay-bs.dat. iii) For the generalized superfluid model the Obninsk group parameters included into the obninsk-bcs.dat file are chosen as recommended ones and the beijing-bcs.dat file is included as an alternative set of parameters. iv) For the microscopic approach to the level densities the files are: obninsk-micro.for -FORTRAN 77 source for the microscopical statistical level density code developed in Obninsk by Ignatyuk and coworkers, moller-levels.gz - Moeller single-particle level and ground state deformation data base, moller-levels.for -retrieval code for Moeller single-particle level scheme. (author)

  2. 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

  3. Soluble organic nutrient fluxes

    Science.gov (United States)

    Robert G. Qualls; Bruce L. Haines; Wayne Swank

    2014-01-01

    Our objectives in this study were (i) compare fluxes of the dissolved organic nutrients dissolved organic carbon (DOC), DON, and dissolved organic phosphorus (DOP) in a clearcut area and an adjacent mature reference area. (ii) determine whether concentrations of dissolved organic nutrients or inorganic nutrients were greater in clearcut areas than in reference areas,...

  4. Flux vacua and supermanifolds

    Energy Technology Data Exchange (ETDEWEB)

    Grassi, Pietro Antonio [CERN, Theory Unit, CH-1211 Geneva, 23 (Switzerland); Marescotti, Matteo [Dipartimento di Fisica Teorica, Universita di Torino, Via Giuria 1, I-10125, Turin (Italy)

    2007-01-15

    As been recently pointed out, physically relevant models derived from string theory require the presence of non-vanishing form fluxes besides the usual geometrical constraints. In the case of NS-NS fluxes, the Generalized Complex Geometry encodes these informations in a beautiful geometrical structure. On the other hand, the R-R fluxes call for supergeometry as the underlying mathematical framework. In this context, we analyze the possibility of constructing interesting supermanifolds recasting the geometrical data and RR fluxes. To characterize these supermanifolds we have been guided by the fact topological strings on supermanifolds require the super-Ricci flatness of the target space. This can be achieved by adding to a given bosonic manifold enough anticommuting coordinates and new constraints on the bosonic sub-manifold. We study these constraints at the linear and non-linear level for a pure geometrical setting and in the presence of p-form field strengths. We find that certain spaces admit several super-extensions and we give a parameterization in a simple case of d bosonic coordinates and two fermionic coordinates. In addition, we comment on the role of the RR field in the construction of the super-metric. We give several examples based on supergroup manifolds and coset supermanifolds.

  5. Flux vacua and supermanifolds

    International Nuclear Information System (INIS)

    Grassi, Pietro Antonio; Marescotti, Matteo

    2007-01-01

    As been recently pointed out, physically relevant models derived from string theory require the presence of non-vanishing form fluxes besides the usual geometrical constraints. In the case of NS-NS fluxes, the Generalized Complex Geometry encodes these informations in a beautiful geometrical structure. On the other hand, the R-R fluxes call for supergeometry as the underlying mathematical framework. In this context, we analyze the possibility of constructing interesting supermanifolds recasting the geometrical data and RR fluxes. To characterize these supermanifolds we have been guided by the fact topological strings on supermanifolds require the super-Ricci flatness of the target space. This can be achieved by adding to a given bosonic manifold enough anticommuting coordinates and new constraints on the bosonic sub-manifold. We study these constraints at the linear and non-linear level for a pure geometrical setting and in the presence of p-form field strengths. We find that certain spaces admit several super-extensions and we give a parameterization in a simple case of d bosonic coordinates and two fermionic coordinates. In addition, we comment on the role of the RR field in the construction of the super-metric. We give several examples based on supergroup manifolds and coset supermanifolds

  6. Atmospheric neutrino fluxes

    International Nuclear Information System (INIS)

    Perkins, D.H.

    1984-01-01

    The atmospheric neutrino fluxes, which are responsible for the main background in proton decay experiments, have been calculated by two independent methods. There are discrepancies between the two sets of results regarding latitude effects and up-down asymmetries, especially for neutrino energies Esub(ν) < 1 GeV. (author)

  7. Flux scaling: Ultimate regime

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Flux scaling: Ultimate regime. With the Nusselt number and the mixing length scales, we get the Nusselt number and Reynolds number (w'd/ν) scalings: and or. and. scaling expected to occur at extremely high Ra Rayleigh-Benard convection. Get the ultimate regime ...

  8. Quasi-B-mode generated by high-frequency gravitational waves and corresponding perturbative photon fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fangyu, E-mail: cqufangyuli@hotmail.com [Institute of Gravitational Physics, Department of Physics, Chongqing University, Chongqing 400044 (China); Wen, Hao [Institute of Gravitational Physics, Department of Physics, Chongqing University, Chongqing 400044 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Fang, Zhenyun [Institute of Gravitational Physics, Department of Physics, Chongqing University, Chongqing 400044 (China); Wei, Lianfu; Wang, Yiwen; Zhang, Miao [Quantum Optoelectronics Laboratory, Southwest Jiaotong University, Chengdu 610031 (China)

    2016-10-15

    Interaction of very low-frequency primordial (relic) gravitational waves (GWs) to cosmic microwave background (CMB) can generate B-mode polarization. Here, for the first time we point out that the electromagnetic (EM) response to high-frequency GWs (HFGWs) would produce quasi-B-mode distribution of the perturbative photon fluxes. We study the duality and high complementarity between such two B-modes, and it is shown that such two effects are from the same physical origin: the tensor perturbation of the GWs and not the density perturbation. Based on this quasi-B-mode in HFGWs and related numerical calculation, it is shown that the distinguishing and observing of HFGWs from the braneworld would be quite possible due to their large amplitude, higher frequency and very different physical behaviors between the perturbative photon fluxes and background photons, and the measurement of relic HFGWs may also be possible though face to enormous challenge.

  9. Quasi-B-mode generated by high-frequency gravitational waves and corresponding perturbative photon fluxes

    Directory of Open Access Journals (Sweden)

    F.Y. Fangyu Li

    2016-10-01

    Full Text Available Interaction of very low-frequency primordial (relic gravitational waves (GWs to cosmic microwave background (CMB can generate B-mode polarization. Here, for the first time we point out that the electromagnetic (EM response to high-frequency GWs (HFGWs would produce quasi-B-mode distribution of the perturbative photon fluxes. We study the duality and high complementarity between such two B-modes, and it is shown that such two effects are from the same physical origin: the tensor perturbation of the GWs and not the density perturbation. Based on this quasi-B-mode in HFGWs and related numerical calculation, it is shown that the distinguishing and observing of HFGWs from the braneworld would be quite possible due to their large amplitude, higher frequency and very different physical behaviors between the perturbative photon fluxes and background photons, and the measurement of relic HFGWs may also be possible though face to enormous challenge.

  10. Coccolithophore fluxes in the open tropical North Atlantic: influence of thermocline depth, Amazon water, and Saharan dust

    Science.gov (United States)

    Guerreiro, Catarina V.; Baumann, Karl-Heinz; Brummer, Geert-Jan A.; Fischer, Gerhard; Korte, Laura F.; Merkel, Ute; Sá, Carolina; de Stigter, Henko; Stuut, Jan-Berend W.

    2017-10-01

    Coccolithophores are calcifying phytoplankton and major contributors to both the organic and inorganic oceanic carbon pumps. Their export fluxes, species composition, and seasonal patterns were determined in two sediment trap moorings (M4 at 12° N, 49° W and M2 at 14° N, 37° W) collecting settling particles synchronously from October 2012 to November 2013 at 1200 m of water depth in the open equatorial North Atlantic. The two trap locations showed a similar seasonal pattern in total coccolith export fluxes and a predominantly tropical coccolithophore settling assemblage. Species fluxes were dominated throughout the year by lower photic zone (LPZ) taxa (Florisphaera profunda, Gladiolithus flabellatus) but also included upper photic zone (UPZ) taxa (Umbellosphaera spp., Rhabdosphaera spp., Umbilicosphaera spp., Helicosphaera spp.). The LPZ flora was most abundant during fall 2012, whereas the UPZ flora was more important during summer. In spite of these similarities, the western part of the study area produced persistently higher fluxes, averaging 241×107 ± 76×107 coccoliths m-2 d-1 at station M4 compared to only 66×107 ± 31×107 coccoliths m-2 d-1 at station M2. Higher fluxes at M4 were mainly produced by the LPZ species, favoured by the westward deepening of the thermocline and nutricline. Still, most UPZ species also contributed to higher fluxes, reflecting enhanced productivity in the western equatorial North Atlantic. Such was the case of two marked flux peaks of the more opportunistic species Gephyrocapsa muellerae and Emiliania huxleyi in January and April 2013 at M4, indicating a fast response to the nutrient enrichment of the UPZ, probably by wind-forced mixing. Later, increased fluxes of G. oceanica and E. huxleyi in October-November 2013 coincided with the occurrence of Amazon-River-affected surface waters. Since the spring and fall events of 2013 were also accompanied by two dust flux peaks, we propose a scenario in which atmospheric dust also

  11. On the theory of critical currents and flux flow in superconductors by the mechanism of plastic deformation of the flux-line lattice

    International Nuclear Information System (INIS)

    Welch, D.O.

    1999-01-01

    In this paper the author will discuss how the nature of the stress state in the flux-line lattice (FLL) of superconductors arises from the distribution, density, geometry, and strength of pinning centers. Under certain conditions this stress causes the onset of plastic deformation in the FLL for values of the current density below that required for flux-flow by general depinning. He will describe an analytic framework, based on a theory of plasticity of the FLL, which describes the flux-flow characteristics, including the possibility of thermally-activated flow and flux creep

  12. Analysis of flux reduction behaviors of PRO hollow fiber membranes: Experiments, mechanisms, and implications

    KAUST Repository

    Xiong, Jun Ying

    2016-01-15

    Pressure retarded osmosis (PRO) is a promising technology to harvest renewable osmotic energy using a semipermeable membrane. However, a significant flux reduction has been always observed that severely shrinks the harvestable power to a level only marginally higher or even lower than the economically feasible value. This work focuses on the elucidation of various underlying mechanisms responsible for the flux reduction. First, both inner-selective and outer-selective thin film composite (TFC) hollow fiber membranes are employed to examine how the fundamental internal factors (such as the surface salinity of the selective layer at the feed side (CF,m) and its components) interact with one another under the fixed bulk salinity gradient, resulting in various behaviours of external performance indexes such as water flux, reverse salt flux, and power density. Then, the research is extended to investigate the effects of the growing bulk feed salinity due to the accumulated reverse salt flux along PRO modules. Finally, the insights obtained from the prior two stationary conditions are combined with the advanced nucleation theory to elucidate the dynamic scaling process by visualizing how the multiple fundamental factors (such as local supersaturation, nucleation rate and nuclei size) evolve and interplay with one another in various membrane regimes during the whole scaling process. To our best knowledge, it is the first time that the advanced nucleation theory is applied to study the PRO scaling kinetics in order to provide subtle and clear pictures of the events occurring inside the membrane. This study may provide useful insights to design more suitable TFC hollow fiber membranes and to operate them with enhanced water flux so that the PRO process may become more promising in the near future.

  13. Advective and diapycnal diffusive oceanic flux in Tenerife - La Gomera Channel

    Science.gov (United States)

    Marrero-Díaz, A.; Rodriguez-Santana, A.; Hernández-Arencibia, M.; Machín, F.; García-Weil, L.

    2012-04-01

    During the year 2008, using the commercial passenger ship Volcán de Tauce of the Naviera Armas company several months, it was possible to obtain vertical profiles of temperature from expandable bathythermograph probes in eight stations across the Tenerife - La Gomera channel. With these data of temperature we have been estimated vertical sections of potential density and geostrophic transport with high spatial and temporal resolution (5 nm between stations, and one- two months between cruises). The seasonal variability obtained for the geostrophic transport in this channel shows important differences with others Canary Islands channels. From potential density and geostrophic velocity data we estimated the vertical diffusion coefficients and diapycnal diffusive fluxes, using a parameterization that depends of Richardson gradient number. In the center of the channel and close to La Gomera Island, we found higher values for these diffusive fluxes. Convergence and divergence of these fluxes requires further study so that we can draw conclusions about its impact on the distribution of nutrients in the study area and its impact in marine ecosystems. This work is being used in research projects TRAMIC and PROMECA.

  14. CRISS power spectral density

    International Nuclear Information System (INIS)

    Vaeth, W.

    1979-04-01

    The correlation of signal components at different frequencies like higher harmonics cannot be detected by a normal power spectral density measurement, since this technique correlates only components at the same frequency. This paper describes a special method for measuring the correlation of two signal components at different frequencies: the CRISS power spectral density. From this new function in frequency analysis, the correlation of two components can be determined quantitatively either they stem from one signal or from two diverse signals. The principle of the method, suitable for the higher harmonics of a signal as well as for any other frequency combinations is shown for the digital frequency analysis technique. Two examples of CRISS power spectral densities demonstrates the operation of the new method. (orig.) [de

  15. Novel Transverse Flux Machine for Vehicle Traction Applications: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Z.; Ahmed, A.; Husain, I.; Muljadi, E.

    2015-04-02

    A novel transverse flux machine topology for electric vehicle traction applications using ferrite magnets is presented in this paper. The proposed transverse flux topology utilizes novel magnet arrangements in the rotor that are similar to the Halbach array to boost flux linkage; on the stator side, cores are alternately arranged around a pair of ring windings in each phase to make use of the entire rotor flux that eliminates end windings. Analytical design considerations and finite-element methods are used for an optimized design of a scooter in-wheel motor. Simulation results from finite element analysis (FEA) show that the motor achieved comparable torque density to conventional rare-earth permanent magnet (PM) machines. This machine is a viable candidate for direct-drive applications with low cost and high torque density.

  16. Angular dependence of energy and particle fluxes in a magnetized plasma

    International Nuclear Information System (INIS)

    Koch, B.; Bohmeyer, W.; Fussmann, G.

    2005-01-01

    A flat probe allowing simultaneous measurements of energy flux and current density as functions of a bias voltage was rotated in a spatially homogeneous plasma. The experiments were conducted at the PSI-2 facility, a linear divertor simulator with moderate magnetic field strength. Sheath parameters (ion current density j i , floating potential U f , energy flux density q, ion energy reflection coefficient R E and sheath energy transmission coefficient γ) were determined as functions of the angle α between the probe surface normal and the magnetic field. A geometric model has been developed to explain the ion flux density at grazing incidence

  17. Correlations Between Magnetic Flux and Levitation Force of HTS Bulk Above a Permanent Magnet Guideway

    Science.gov (United States)

    Huang, Huan; Zheng, Jun; Zheng, Botian; Qian, Nan; Li, Haitao; Li, Jipeng; Deng, Zigang

    2017-10-01

    In order to clarify the correlations between magnetic flux and levitation force of the high-temperature superconducting (HTS) bulk, we measured the magnetic flux density on bottom and top surfaces of a bulk superconductor while vertically moving above a permanent magnet guideway (PMG). The levitation force of the bulk superconductor was measured simultaneously. In this study, the HTS bulk was moved down and up for three times between field-cooling position and working position above the PMG, followed by a relaxation measurement of 300 s at the minimum height position. During the whole processes, the magnetic flux density and levitation force of the bulk superconductor were recorded and collected by a multipoint magnetic field measurement platform and a self-developed maglev measurement system, respectively. The magnetic flux density on the bottom surface reflected the induced field in the superconductor bulk, while on the top, it reveals the penetrated magnetic flux. The results show that the magnetic flux density and levitation force of the bulk superconductor are in direct correlation from the viewpoint of inner supercurrent. In general, this work is instructive for understanding the connection of the magnetic flux density, the inner current density and the levitation behavior of HTS bulk employed in a maglev system. Meanwhile, this magnetic flux density measurement method has enriched present experimental evaluation methods of maglev system.

  18. 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)

  19. Design of a flux buffer based on the flux shuttle

    International Nuclear Information System (INIS)

    Gershenson, M.

    1991-01-01

    This paper discusses the design considerations for a flux buffer based on the flux-shuttle concept. Particular attention is given to the issues of flux popping, stability of operation and saturation levels for a large input. Modulation techniques used in order to minimize 1/f noise, in addition to offsets are also analyzed. Advantages over conventional approaches using a SQUID for a flux buffer are discussed. Results of computer simulations are presented

  20. Radiolarian fluxes from the southern Bay of Bengal: sediment trap results

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, S.M.; Mohan, R; Guptha, M.V.S.

    the monsoonal rainfall. Higher radiolarian fluxes occurred during March-May, when moderate salinity and a high sea surface temperature (SST) regime prevailed at the trap site. R-mode cluster analysis of the radiolarian flux data revealed three assemblages...

  1. Lobotomy of flux compactifications

    Energy Technology Data Exchange (ETDEWEB)

    Dibitetto, Giuseppe [Institutionen för fysik och astronomi, University of Uppsala,Box 803, SE-751 08 Uppsala (Sweden); Guarino, Adolfo [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics,Bern University, Sidlerstrasse 5, CH-3012 Bern (Switzerland); Roest, Diederik [Centre for Theoretical Physics, University of Groningen,Nijenborgh 4 9747 AG Groningen (Netherlands)

    2014-05-15

    We provide the dictionary between four-dimensional gauged supergravity and type II compactifications on T{sup 6} with metric and gauge fluxes in the absence of supersymmetry breaking sources, such as branes and orientifold planes. Secondly, we prove that there is a unique isotropic compactification allowing for critical points. It corresponds to a type IIA background given by a product of two 3-tori with SO(3) twists and results in a unique theory (gauging) with a non-semisimple gauge algebra. Besides the known four AdS solutions surviving the orientifold projection to N=4 induced by O6-planes, this theory contains a novel AdS solution that requires non-trivial orientifold-odd fluxes, hence being a genuine critical point of the N=8 theory.

  2. Integrated passive flux measurement in groundwater: design and performance of iFLUX samplers

    Science.gov (United States)

    Verreydt, Goedele; Razaei, Meisam; Meire, Patrick; Van Keer, Ilse; Bronders, Jan; Seuntjens, Piet

    2017-04-01

    The monitoring and management of soil and groundwater is a challenge. Current methods for the determination of movement or flux of pollution in groundwater use no direct measurements but only simulations based on concentration measurements and Darcy velocity estimations. This entails large uncertainties which cause remediation failures and higher costs for contaminated site owners. On top of that, the lack of useful data makes it difficult to get approval for a risk-based management approach which completely avoids costly remedial actions. The iFLUX technology is a key development of Dr. Goedele Verreydt at the University of Antwerp and VITO. It is supported by the passive flux measurement technology as invented by Prof. Mike Annable and his team at the University of Florida. The iFLUX technology includes an in situ measurement device for capturing dynamic groundwater quality and quantity, the iFLUX sampler, and an associated interpretation and visualization method. The iFLUX sampler is a modular passive sampler that provides simultaneous in situ point determinations of a time-averaged target compound mass flux and water flux. The sampler is typically installed in a monitoring well where it intercepts the groundwater flow and captures the compounds of interest. The sampler consists of permeable cartridges which are each packed with a specific sorbent matrix. The sorbent matrix of the water flux cartridge is impregnated with known amounts of water soluble resident tracers. These tracers are leached from the matrix at rates proportional to the groundwater flux. The measurements of the contaminants and the remaining resident tracer are used to determine groundwater and target compound fluxes. Exposure times range from 1 week to 6 months, depending on the expected concentration and groundwater flow velocity. The iFLUX sampler technology has been validated and tested at several field projects. Currently, 4 cartridges are tested and available: 1 waterflux cartridge to

  3. Physics of magnetic flux ropes

    Science.gov (United States)

    Russell, C. T.; Priest, E. R.; Lee, L. C.

    The present work encompasses papers on the structure, waves, and instabilities of magnetic flux ropes (MFRs), photospheric flux tubes (PFTs), the structure and heating of coronal loops, solar prominences, coronal mass ejections and magnetic clouds, flux ropes in planetary ionospheres, the magnetopause, magnetospheric field-aligned currents and flux tubes, and the magnetotail. Attention is given to the equilibrium of MFRs, resistive instability, magnetic reconnection and turbulence in current sheets, dynamical effects and energy transport in intense flux tubes, waves in solar PFTs, twisted flux ropes in the solar corona, an electrodynamical model of solar flares, filament cooling and condensation in a sheared magnetic field, the magnetopause, the generation of twisted MFRs during magnetic reconnection, ionospheric flux ropes above the South Pole, substorms and MFR structures, evidence for flux ropes in the earth magnetotail, and MFRs in 3D MHD simulations.

  4. Estimating daytime ecosystem respiration from eddy-flux data

    DEFF Research Database (Denmark)

    Bruhn, Dan; Mikkelsen, Teis Nørgaard; Herbst, Mathias

    2011-01-01

    To understand what governs the patterns of net ecosystem exchange of CO2, an understanding of factors influencing the component fluxes, ecosystem respiration and gross primary production is needed. In the present paper, we introduce an alternative method for estimating daytime ecosystem respiration...... based on whole ecosystem fluxes from a linear regression of photosynthetic photon flux density data vs. daytime net ecosystem exchange data at forest ecosystem level. This method is based on the principles of the Kok-method applied at leaf level for estimating daytime respiration. We demonstrate...

  5. Flux-line-cutting losses in type-II superconductors

    International Nuclear Information System (INIS)

    Clem, J.R.

    1982-01-01

    Energy dissipation associated with flux-line cutting (intersection and cross-joining of adjacent nonparallel vortices) is considered theoretically. The flux-line-cutting contribution to the dissipation per unit volume, arising from mutual annihilation of transverse magnetic flux, is identified as J/sub parallel/xE/sub parallel/, where J/sub parallel/ and E/sub parallel/ are the components of the current density and the electric field parallel to the magnetic induction. The dynamical behavior of the magnetic structure at the flux-line-cutting threshold is shown to be governed by a special critical-state model similar to that proposed by previous authors. The resulting flux-line-cutting critical-state model, characterized in planar geometry by a parallel critical current density J/sub c/parallel or a critical angle gradient k/sub c/, is used to calculate predicted hysteretic ac flux-line-cutting losses in type-II superconductors in which the flux pinning is weak. The relation of the theory to previous experiments is discussed

  6. 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.

  7. High density dispersion fuel

    International Nuclear Information System (INIS)

    Hofman, G.L.

    1996-01-01

    A fuel development campaign that results in an aluminum plate-type fuel of unlimited LEU burnup capability with an uranium loading of 9 grams per cm 3 of meat should be considered an unqualified success. The current worldwide approved and accepted highest loading is 4.8 g cm -3 with U 3 Si 2 as fuel. High-density uranium compounds offer no real density advantage over U 3 Si 2 and have less desirable fabrication and performance characteristics as well. Of the higher-density compounds, U 3 Si has approximately a 30% higher uranium density but the density of the U 6 X compounds would yield the factor 1.5 needed to achieve 9 g cm -3 uranium loading. Unfortunately, irradiation tests proved these peritectic compounds have poor swelling behavior. It is for this reason that the authors are turning to uranium alloys. The reason pure uranium was not seriously considered as a dispersion fuel is mainly due to its high rate of growth and swelling at low temperatures. This problem was solved at least for relatively low burnup application in non-dispersion fuel elements with small additions of Si, Fe, and Al. This so called adjusted uranium has nearly the same density as pure α-uranium and it seems prudent to reconsider this alloy as a dispersant. Further modifications of uranium metal to achieve higher burnup swelling stability involve stabilization of the cubic γ phase at low temperatures where normally α phase exists. Several low neutron capture cross section elements such as Zr, Nb, Ti and Mo accomplish this in various degrees. The challenge is to produce a suitable form of fuel powder and develop a plate fabrication procedure, as well as obtain high burnup capability through irradiation testing

  8. Enhancement of magnetic flux distribution in a DC superconducting electric motor

    International Nuclear Information System (INIS)

    Hamid, N A; Ewe, L S; Chin, K M

    2013-01-01

    Most motor designs require an air gap between the rotor and stator to enable the armature to rotate freely. The interaction of magnetic flux from rotor and stator within the air gap will provide the thrust for rotational motion. Thus, the understanding of magnetic flux in the vicinity of the air gap is very important to mathematically calculate the magnetic flux generated in the area. In this work, a finite element analysis was employed to study the behavior of the magnetic flux in view of designing a synchronous DC superconducting electric motor. The analysis provides an ideal magnetic flux distribution within the components of the motor. From the flux plot analysis, it indicates that flux losses are mainly in the forms of leakage and fringe effect. The analysis also shows that the flux density is high at the area around the air gap and the rotor. The high flux density will provide a high force area that enables the rotor to rotate. In contrast, the other parts of the motor body do not show high flux density indicating low distribution of flux. Consequently, a bench top model of a DC superconducting motor was developed where by motor with a 2-pole type winding was chosen. Each field coil was designed with a racetrack-shaped double pancake wound using DI-BSCCO Bi-2223 superconducting tapes. The performance and energy efficiency of the superconducting motor was superior when compared to the conventional motor with similar capacity.

  9. Australian methane fluxes

    International Nuclear Information System (INIS)

    Williams, D.J.

    1990-01-01

    Estimates are provided for the amount of methane emitted annually into the atmosphere in Australia for a variety of sources. The sources considered are coal mining, landfill, motor vehicles, natural gas suply system, rice paddies, bushfires, termites, wetland and animals. This assessment indicates that the major sources of methane are natural or agricultural in nature and therefore offer little scope for reduction. Nevertheless the remainder are not trival and reduction of these fluxes could play a significant part in any Australian action on the greenhouse problem. 19 refs., 7 tabs., 1 fig

  10. Determination of lead 210 atmospheric fluxes in Syria

    International Nuclear Information System (INIS)

    Al-Masri, M. S.; Shaik Khalil, H.

    2001-01-01

    Lead 210 atmospheric fluxes were determined by collecting 51 profiles from Syrian soil during 1998. Lead 210 fluxes in Syria calculated from lead 210 inventory in soil ranged from 15 Bq.m -2 .y -1 and 407 Bq.m -2 .y -1 with an average value of 128 Bq.m -2 .y -1 . the highest fluxes were found to be in Hama area due to the Gaab fault, which is considered as a radon source in the area. In addition, fluxes were also high in most sites, which are located in Syria valleys and around the lakes. Moreover, the study has indicated that there is no linear relation between lead 210 flux values and other parameters such as annual rainfall and bulk density of the soil. On the other hand, an effect, of those two factors on lead 210 distribution with depth has been observed. In addition, the results of variable lead 210 fluxes from site to another have proved that it is necessary, in order to obtain a representative mean value of lead 210 flux obtained in this study is within the worldwide range for lead 210 flux. (Author)

  11. Magnetic flux reconstruction methods for shaped tokamaks

    International Nuclear Information System (INIS)

    Tsui, Chi-Wa.

    1993-12-01

    The use of a variational method permits the Grad-Shafranov (GS) equation to be solved by reducing the problem of solving the 2D non-linear partial differential equation to the problem of minimizing a function of several variables. This high speed algorithm approximately solves the GS equation given a parameterization of the plasma boundary and the current profile (p' and FF' functions). The author treats the current profile parameters as unknowns. The goal is to reconstruct the internal magnetic flux surfaces of a tokamak plasma and the toroidal current density profile from the external magnetic measurements. This is a classic problem of inverse equilibrium determination. The current profile parameters can be evaluated by several different matching procedures. Matching of magnetic flux and field at the probe locations using the Biot-Savart law and magnetic Green's function provides a robust method of magnetic reconstruction. The matching of poloidal magnetic field on the plasma surface provides a unique method of identifying the plasma current profile. However, the power of this method is greatly compromised by the experimental errors of the magnetic signals. The Casing Principle provides a very fast way to evaluate the plasma contribution to the magnetic signals. It has the potential of being a fast matching method. The performance of this method is hindered by the accuracy of the poloidal magnetic field computed from the equilibrium solver. A flux reconstruction package has been implemented which integrates a vacuum field solver using a filament model for the plasma, a multi-layer perception neural network as an interface, and the volume integration of plasma current density using Green's functions as a matching method for the current profile parameters. The flux reconstruction package is applied to compare with the ASEQ and EFIT data. The results are promising

  12. Measuring Convective Mass Fluxes Over Tropical Oceans

    Science.gov (United States)

    Raymond, David

    2017-04-01

    Deep convection forms the upward branches of all large-scale circulations in the tropics. Understanding what controls the form and intensity of vertical convective mass fluxes is thus key to understanding tropical weather and climate. These mass fluxes and the corresponding conditions supporting them have been measured by recent field programs (TPARC/TCS08, PREDICT, HS3) in tropical disturbances considered to be possible tropical storm precursors. In reality, this encompasses most strong convection in the tropics. The measurements were made with arrays of dropsondes deployed from high altitude. In some cases Doppler radar provided additional measurements. The results are in some ways surprising. Three factors were found to control the mass flux profiles, the strength of total surface heat fluxes, the column-integrated relative humidity, and the low to mid-tropospheric moist convective instability. The first two act as expected, with larger heat fluxes and higher humidity producing more precipitation and stronger lower tropospheric mass fluxes. However, unexpectedly, smaller (but still positive) convective instability produces more precipitation as well as more bottom-heavy convective mass flux profiles. Furthermore, the column humidity and the convective instability are anti-correlated, at least in the presence of strong convection. On spatial scales of a few hundred kilometers, the virtual temperature structure appears to be in dynamic balance with the pattern of potential vorticity. Since potential vorticity typically evolves on longer time scales than convection, the potential vorticity pattern plus the surface heat fluxes then become the immediate controlling factors for average convective properties. All measurements so far have taken place in regions with relatively flat sea surface temperature (SST) distributions. We are currently seeking funding for a measurement program in the tropical east Pacific, a region that exhibits strong SST gradients and

  13. Nitrous oxide fluxes and nitrogen cycling along a pasture chronosequence in Central Amazonia, Brazil

    Directory of Open Access Journals (Sweden)

    B. Wick

    2005-01-01

    Full Text Available We studied nitrous oxide (N2O fluxes and soil nitrogen (N cycling following forest conversion to pasture in the central Amazon near Santarém, Pará, Brazil. Two undisturbed forest sites and 27 pasture sites of 0.5 to 60 years were sampled once each during wet and dry seasons. In addition to soil-atmosphere fluxes of N2O we measured 27 soil chemical, soil microbiological and soil physical variables. Soil N2O fluxes were higher in the wet season than in the dry season. Fluxes of N2O from forest soils always exceeded fluxes from pasture soils and showed no consistent trend with pasture age. At our forest sites, nitrate was the dominant form of inorganic N both during wet and dry season. At our pasture sites nitrate generally dominated the inorganic N pools during the wet season and ammonium dominated during the dry season. Net mineralization and nitrification rates displayed large variations. During the dry season net immobilization of N was observed in some pastures. Compared to forest sites, young pasture sites (≤2 years had low microbial biomass N and protease activities. Protease activity and microbial biomass N peaked in pastures of intermediate age (4 to 8 years followed by consistently lower values in older pasture (10 to 60 years. The C/N ratio of litter was low at the forest sites (~25 and rapidly increased with pasture age reaching values of 60-70 at pastures of 15 years and older. Nitrous oxide emissions at our sites were controlled by C and N availability and soil aeration. Fluxes of N2O were negatively correlated to leaf litter C/N ratio, NH4+-N and the ratio of NO3--N to the sum of NO3--N + NH4+-N (indicators of N availability, and methane fluxes and bulk density (indicators of soil aeration status during the wet season. During the dry season fluxes of N2O were positively correlated to microbial biomass N, β-glucosidase activity, total inorganic N stocks and NH4+-N. In our study region, pastures of all age emitted less N2O than

  14. Critical heat flux evaluation

    International Nuclear Information System (INIS)

    Banner, D.

    1995-01-01

    Critical heat flux (CHF) is of importance for nuclear safety and represents the major limiting factors for reactor cores. Critical heat flux is caused by a sharp reduction in the heat transfer coefficient located at the outer surface of fuel rods. Safety requires that this phenomenon also called the boiling crisis should be precluded under nominal or incidental conditions (Class I and II events). CHF evaluation in reactor cores is basically a two-step approach. Fuel assemblies are first tested in experimental loops in order to determine CHF limits under various flow conditions. Then, core thermal-hydraulic calculations are performed for safety evaluation. The paper will go into more details about the boiling crisis in order to pinpoint complexity and lack of fundamental understanding in many areas. Experimental test sections needed to collect data over wide thermal-hydraulic and geometric ranges are described CHF safety margin evaluation in reactors cores is discussed by presenting how uncertainties are mentioned. From basic considerations to current concerns, the following topics are discussed; knowledge of the boiling crisis, CHF predictors, and advances thermal-hydraulic codes. (authors). 15 refs., 4 figs

  15. Neutron flux monitor

    International Nuclear Information System (INIS)

    Seki, Eiji; Tai, Ichiro.

    1984-01-01

    Purpose: To maintain the measuring accuracy and the reponse time within an allowable range in accordance with the change of neutron fluxes in a nuclear reactor pressure vessel. Constitution: Neutron fluxes within a nuclear reactor pressure vessel are detected by detectors, converted into pulse signals and amplified in a range switching amplifier. The amplified signals are further converted through an A/D converter and digital signals from the converter are subjected to a square operation in an square operation circuit. The output from the circuit is inputted into an integration circuit to selectively accumulate the constant of 1/2n, 1 - 1/2n (n is a positive integer) respectively for two continuing signals to perform weighing. Then, the addition is carried out to calculate the integrated value and the addition number is changed by the chane in the number n to vary the integrating time. The integrated value is inputted into a control circuit to control the value of n so that the fluctuation and the calculation time for the integrated value are within a predetermined range and, at the same time, the gain of the range switching amplifier is controlled. (Seki, T.)

  16. Design and fabrication of radial flux permanent magnet generator for wind turbine applications

    International Nuclear Information System (INIS)

    Ashraf, M.M.; Malik, T.N.; Zafar, S.; Raja, U.N.

    2013-01-01

    Presently alternate energy resources are replacing conventional energy sources to produce electrical power to minimize the usage of fossil fuels. Wind power is one of the potential alternate energy resources and is being exploited and deployed actively. The wind energy system is basically composed of two core components: wind turbine and electrical generator. This paper presents the design and fabrication of permanent magnet generator for direct drive wind turbine applications. Radial flux permanent magnet generator (RFPMG) producing three phase alternating current voltage has been designed subject to satisfying the features of low operating shaft speed, higher power density , higher current density, cost effectiveness and compact structure. RFPMG design focuses on usage of neodymium permanent magnets for excitation instead of electromagnets to minimize the excitation arrangement challenges and losses. A 300 W prototype RFPMG has been fabricated. The performance of the generator has been evaluated on specially designed wind tunnel. The generator is directly coupled with wind turbine shaft to eliminate the gearbox losses. No load and load tests show that the performance of the machine is up to the mark. The improved design parameters of power density and current density are 73.2 W/kg and 5.9 A/mm 2 respectively. The same machine output has been rectified using bridge rectifier for battery charging application. The desired output voltages are obtained at minimum shaft speed of the generator. Thus the design of generator confirms its application with small scale domestic wind turbines produci ng direct current supply. (author)

  17. Elliptic-cylindrical analytical flux-rope model for ICMEs

    Science.gov (United States)

    Nieves-Chinchilla, T.; Linton, M.; Hidalgo, M. A. U.; Vourlidas, A.

    2016-12-01

    We present an analytical flux-rope model for realistic magnetic structures embedded in Interplanetary Coronal Mass Ejections. The framework of this model was established by Nieves-Chinchilla et al. (2016) with the circular-cylindrical analytical flux rope model and under the concept developed by Hidalgo et al. (2002). Elliptic-cylindrical geometry establishes the first-grade of complexity of a series of models. The model attempts to describe the magnetic flux rope topology with distorted cross-section as a possible consequence of the interaction with the solar wind. In this model, the flux rope is completely described in the non-euclidean geometry. The Maxwell equations are solved using tensor calculus consistently with the geometry chosen, invariance along the axial component, and with the only assumption of no radial current density. The model is generalized in terms of the radial dependence of the poloidal current density component and axial current density component. The misalignment between current density and magnetic field is studied in detail for the individual cases of different pairs of indexes for the axial and poloidal current density components. This theoretical analysis provides a map of the force distribution inside of the flux-rope. The reconstruction technique has been adapted to the model and compared with in situ ICME set of events with different in situ signatures. The successful result is limited to some cases with clear in-situ signatures of distortion. However, the model adds a piece in the puzzle of the physical-analytical representation of these magnetic structures. Other effects such as axial curvature, expansion and/or interaction could be incorporated in the future to fully understand the magnetic structure. Finally, the mathematical formulation of this model opens the door to the next model: toroidal flux rope analytical model.

  18. Stabilization of electron-scale turbulence by electron density gradient in national spherical torus experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Ruiz, J.; White, A. E. [MIT-Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Ren, Y.; Guttenfelder, W.; Kaye, S. M.; Leblanc, B. P.; Mazzucato, E. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Lee, K. C. [National Fusion Research Institute, Daejeon (Korea, Republic of); Domier, C. W. [University of California at Davis, Davis, California 95616 (United States); Smith, D. R. [University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Yuh, H. [Nova Photonics, Inc., Princeton, New Jersey 08540 (United States)

    2015-12-15

    Theory and experiments have shown that electron temperature gradient (ETG) turbulence on the electron gyro-scale, k{sub ⊥}ρ{sub e} ≲ 1, can be responsible for anomalous electron thermal transport in NSTX. Electron scale (high-k) turbulence is diagnosed in NSTX with a high-k microwave scattering system [D. R. Smith et al., Rev. Sci. Instrum. 79, 123501 (2008)]. Here we report on stabilization effects of the electron density gradient on electron-scale density fluctuations in a set of neutral beam injection heated H-mode plasmas. We found that the absence of high-k density fluctuations from measurements is correlated with large equilibrium density gradient, which is shown to be consistent with linear stabilization of ETG modes due to the density gradient using the analytical ETG linear threshold in F. Jenko et al. [Phys. Plasmas 8, 4096 (2001)] and linear gyrokinetic simulations with GS2 [M. Kotschenreuther et al., Comput. Phys. Commun. 88, 128 (1995)]. We also found that the observed power of electron-scale turbulence (when it exists) is anti-correlated with the equilibrium density gradient, suggesting density gradient as a nonlinear stabilizing mechanism. Higher density gradients give rise to lower values of the plasma frame frequency, calculated based on the Doppler shift of the measured density fluctuations. Linear gyrokinetic simulations show that higher values of the electron density gradient reduce the value of the real frequency, in agreement with experimental observation. Nonlinear electron-scale gyrokinetic simulations show that high electron density gradient reduces electron heat flux and stiffness, and increases the ETG nonlinear threshold, consistent with experimental observations.

  19. Flux structures in mesoscopic Y Ba2Cu3O7-δ discs

    International Nuclear Information System (INIS)

    Crisan, A; Bending, S J; Pross, A; Aziz, A; Grigorenko, A N; Humphreys, R G

    2005-01-01

    Scanning Hall probe microscopy has been used to study flux structures and dynamics in 5 μm x 5 μm YBCO thin film squares, which are mesoscopic with respect to the magnetic penetration depth, λ(T), at temperatures close to T c . A number of unusual vortex phenomena are observed in these microstructures which differ qualitatively from the expected behaviour of more macroscopic pieces of film. In field-cooled (FC) experiments to ∼65K a full Meissner state is generated for cooling fields less than ∼6 Oe, reflecting the relatively small demagnetization factors in our samples. Cooling in higher fields, however, results in only a very weak diamagnetic response at low temperatures whose magnitude is almost independent of the cooling field. In contrast we observe considerable trapped flux upon field-removal whose magnitude grows monotonically with cooling field. Remarkably, all FC flux distributions exhibit almost perfect rotational symmetry, and can be nearly completely cancelled in a reversible fashion by tuning the field applied to the initially FC state. Our field-cooled and zero-field-cooled results have been analysed in terms of a Bean-like critical state model containing constant edge and bulk current densities, and most of the observed phenomena can be explained by considering the relative weight of these two components. Not all flux profiles can be described by our simple model, however, and under certain circumstances symmetry-breaking 'dipole'-like flux structures can form in several adjacent YBCO squares. We speculate that these are related to the unidirectional Ar ion milling process which was used to pattern the squares and could have broken the expected four-fold symmetry. We note that our results could have important implications for the miniaturization of thin film HTS devices

  20. Flux threshold measurements of He-ion beam induced nanofuzz formation on hot tungsten surfaces

    International Nuclear Information System (INIS)

    Meyer, F W; Hijazi, H; Bannister, M E; Unocic, K A; Garrison, L M; Parish, C M

    2016-01-01

    We report measurements of the energy dependence of flux thresholds and incubation fluences for He-ion induced nano-fuzz formation on hot tungsten surfaces at UHV conditions over a wide energy range using real-time sample imaging of tungsten target emissivity change to monitor the spatial extent of nano-fuzz growth, corroborated by ex situ SEM and FIB/SEM analysis, in conjunction with accurate ion-flux profile measurements. The measurements were carried out at the multicharged ion research facility (MIRF) at energies from 218 eV to 8.5 keV, using a high-flux deceleration module and beam flux monitor for optimizing the decel optics on the low energy MIRF beamline. The measurements suggest that nano-fuzz formation proceeds only if a critical rate of change of trapped He density in the W target is exceeded. To understand the energy dependence of the observed flux thresholds, the energy dependence of three contributing factors: ion reflection, ion range and target damage creation, were determined using the SRIM simulation code. The observed energy dependence can be well reproduced by the combined energy dependences of these three factors. The incubation fluences deduced from first visual appearance of surface emissivity change were (2–4) × 10 23 m −2 at 218 eV, and roughly a factor of 10 less at the higher energies, which were all at or above the displacement energy threshold. The role of trapping at C impurity sites is discussed. (paper)

  1. Element fluxes from Copahue Volcano, Argentina

    Science.gov (United States)

    Varekamp, J. C.

    2003-12-01

    Copahue volcano in Argentina has an active volcano-magmatic hydrothermal system that emits fluids with pH=0.3 that feed a river system. River flux measurements and analytical data provide element flux data from 1997 to 2003, which includes the eruptive period of July to December 2000. The fluids have up to 6.5 percent sulfate, 1 percent Cl and ppm levels of B, As, Cu, Zn and Pb. The hydrothermal system acts as a perfect scrubber for magmatic gases during the periods of passive degassing, although the dissolved magmatic gases are modified through water rock interaction and mineral precipitation. The magmatic SO2 disproportionates into sulfate and liquid elemental sulfur at about 300 C; the sulfate is discharged with the fluids, whereas the liquid sulfur is temporarily retained in the reservoir but ejected during phreatic and hydrothermal eruptions. The intrusion and chemical attack of new magma in the hydrothermal reservoir in early 2000 was indicated by strongly increased Mg concentrations and Mg fluxes, and higher Mg/Cl and Mg/K values. The hydrothermal discharge has acidified a large glacial lake (0.5 km3) to pH=2 and the lake effluents acidify the exiting river. Even more than 100 km downstream, the effects of acid pulses from the lake are evident from red coated boulders and fish die-offs. The river-bound sulfate fluxes from the system range from 70 to 200 kilotonnes/year. The equivalent SO2 output of the whole volcanic system ranges from 150 to 500 tonnes/day, which includes the fraction of native sulfur that formed inside the mountain but does not include the release of SO2 into the atmosphere during the eruptions. Trace element fluxes of the river will be scaled up and compared with global element fluxes from meteoric river waters (subterranean volcanic weathering versus watershed weathering).

  2. Particle fluxes above forests: Observations, methodological considerations and method comparisons

    International Nuclear Information System (INIS)

    Pryor, S.C.; Larsen, S.E.; Sorensen, L.L.; Barthelmie, R.J.

    2008-01-01

    This paper reports a study designed to test, evaluate and compare micro-meteorological methods for determining the particle number flux above forest canopies. Half-hour average particle number fluxes above a representative broad-leaved forest in Denmark derived using eddy covariance range from -7 x 10 7 m -2 s -1 (1st percentile) to 5 x 10 7 m -2 s -1 (99th percentile), and have a median value of -1.6 x 10 6 m -2 s -1 . The statistical uncertainties associated with the particle number flux estimates are larger than those for momentum fluxes and imply that in this data set approximately half of the particle number fluxes are not statistically different to zero. Particle number fluxes from relaxed eddy accumulation (REA) and eddy covariance are highly correlated and of almost identical magnitude. Flux estimates from the co-spectral and dissipation methods are also correlated with those from eddy covariance but exhibit higher absolute magnitude of fluxes. - Number fluxes of ultra-fine particles over a forest computed using four micro-meteorological techniques are highly correlated but vary in magnitude

  3. Ultraviolet Flux Variation of Epsilon Aurigae

    Directory of Open Access Journals (Sweden)

    Young Woon Kang

    1990-06-01

    Full Text Available The eighteen ultraviolet light curves of Epsilon Aurigae have been plotted using the integrated fluxes reduced from the 233 IUE low dispersion spectra taken between 1978 and 1986. The times of contacts and depth of eclipse have been determined from the light curves at the wavelength from 2550 Å to 3050 Å. The UV light curves show two brightenings during the totality, the downward slope of the variation from the second to the third contacts, and asymmetry of the eclipse light curve. The two selected spectra note that the energy density distribution is not changed between the totality of the eclipse and out-of-eclipse.

  4. Heterotic Hyper-Kähler flux backgrounds

    Science.gov (United States)

    Halmagyi, Nick; Israël, Dan; Sarkis, Matthieu; Svanes, Eirik Eik

    2017-08-01

    We study Heterotic supergravity on Hyper-Kähler manifolds in the presence of non-trivial warping and three form flux with Abelian bundles in the large charge limit. We find exact, regular solutions for multi-centered Gibbons-Hawking spaces and Atiyah-Hitchin manifolds. In the case of Atiyah-Hitchin, regularity requires that the circle at infinity is of the same order as the instanton number, which is taken to be large. Alternatively there may be a non-trivial density of smeared five branes at the bolt.

  5. Contribution of trees and grasses to ecosystem fluxes of water, carbon, and energy throughout the seasons under different nutrient availability

    Science.gov (United States)

    El-Madany, T. S.; Migliavacca, M.; Perez-Priego, O.; Luo, Y.; Moreno, G.; Carrara, A.; Kolle, O.; Reichstein, M.

    2017-12-01

    In semi-arid savanna type ecosystems, the carbon and water cycle are closely related to each other. Water availability is the main driver for the development and phenology of the vegetation, especially for annual plants. Depending on tree density, nutrient availability and species the contribution of the tree- and the herbaceous layer to ecosystem fluxes can vary substantially. We present data from an ecosystem scale nutrient manipulation experiment within a Mediterranean savanna type ecosystem which is used for cattle. The footprint areas of two out of three ecosystem eddy co-variance (EC) towers were fertilized with nitrogen (NT) and nitrogen plus phosphorous (NPT) while the third one served as the control tower (CT). At each ecosystem EC-tower an additional herbaceous layer tower was installed that only sampled fluxes from the herbaceous layer. Under certain assumptions flux differences between the ecosystem EC and the herbaceous layer EC systems can be considered as the contribution of the trees to the ecosystem fluxes. Based on phenology of the herbaceous layer estimated through green-chromatic-coordinates from digital imagery the year was separated into spring, senescence, regreening, and winter. The focus of the analysis is (i) the evaluation of the method and how it works throughout the different seasons and (ii) the quantification of the contribution of trees and grasses to ecosystem fluxes of water, carbon, and energy under different environmental conditions and nutrient stoichiometry. The contribution of the trees to total ecosystem fluxes is variable in time. Especially, during the beginning of the senescence period high evapotranspiration rates and largest carbon uptake are measured while the contribution to sensible heat fluxes is largest during the end of the summer. During the regreening and winter the contribution of ET is relatively constant around 0.25 mm d-1. During the peak of the greenness ET and carbon flux of the herbaceous EC tower are

  6. Characterization of local heat fluxes around ICRF antennas on JET

    Energy Technology Data Exchange (ETDEWEB)

    Campergue, A.-L. [Ecole Nationale des Ponts et Chaussées, F77455 Marne-la-Vallée (France); Jacquet, P.; Monakhov, I.; Arnoux, G.; Brix, M.; Sirinelli, A. [Euratom/CCFE Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Bobkov, V. [Max-Planck-Institut für Plasmaphysik, EURATOM-Assoziation, Garching (Germany); Milanesio, D. [Politecnico di Torino, Department of Electronics, Torino (Italy); Colas, L. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Collaboration: JET-EFDA Contributors

    2014-02-12

    When using Ion Cyclotron Range of Frequency (ICRF) heating, enhanced power deposition on Plasma-Facing Components (PFCs) close to the antennas can occur. Experiments have recently been carried out on JET with the new ITER-Like-Wall (ILW) to characterize the heat fluxes on the protection of the JET ICRF antennas, using Infra-Red (IR) thermography measurement. The measured heat flux patterns along the poloidal limiters surrounding powered antennas were compared to predictions from a simple RF sheath rectification model. The RF electric field, parallel to the static magnetic field in front of the antenna, was evaluated using the TOPICA code, integrating a 3D flattened model of the JET A2 antennas. The poloidal density variation in front of the limiters was obtained from the mapping of the Li-beam or edge reflectometry measurements using the flux surface geometry provided by EFIT equilibrium reconstruction. In many cases, this simple model can well explain the position of the maximum heat flux on the different protection limiters and the heat-flux magnitude, confirming that the parallel RF electric field and the electron plasma density in front of the antenna are the main driving parameters for ICRF-induced local heat fluxes.

  7. Fast Flux Test Facility

    International Nuclear Information System (INIS)

    Munn, W.I.

    1981-01-01

    The Fast Flux Test Facility (FFTF), located on the Hanford site a few miles north of Richland, Washington, is a major link in the chain of development required to sustain and advance Liquid Metal Fast Breeder Reactor (LMFBR) technology in the United States. This 400 MWt sodium cooled reactor is a three loop design, is operated by Westinghouse Hanford Company for the US Department of Energy, and is the largest research reactor of its kind in the world. The purpose of the facility is three-fold: (1) to provide a test bed for components, materials, and breeder reactor fuels which can significantly extend resource reserves; (2) to produce a complete body of base data for the use of liquid sodium in heat transfer systens; and (3) to demonstrate inherent safety characteristics of LMFBR designs

  8. Flux compactifications and generalized geometries

    International Nuclear Information System (INIS)

    Grana, Mariana

    2006-01-01

    Following the lectures given at CERN Winter School 2006, we present a pedagogical overview of flux compactifications and generalized geometries, concentrating on closed string fluxes in type II theories. We start by reviewing the supersymmetric flux configurations with maximally symmetric four-dimensional spaces. We then discuss the no-go theorems (and their evasion) for compactifications with fluxes. We analyse the resulting four-dimensional effective theories for Calabi-Yau and Calabi-Yau orientifold compactifications, concentrating on the flux-induced superpotentials. We discuss the generic mechanism of moduli stabilization and illustrate with two examples: the conifold in IIB and a T 6 /(Z 3 x Z 3 ) torus in IIA. We finish by studying the effective action and flux vacua for generalized geometries in the context of generalized complex geometry

  9. Flux compactifications and generalized geometries

    Energy Technology Data Exchange (ETDEWEB)

    Grana, Mariana [Service de Physique Theorique, CEA/Saclay, 91191 Gif-sur-Yvette Cedex (France)

    2006-11-07

    Following the lectures given at CERN Winter School 2006, we present a pedagogical overview of flux compactifications and generalized geometries, concentrating on closed string fluxes in type II theories. We start by reviewing the supersymmetric flux configurations with maximally symmetric four-dimensional spaces. We then discuss the no-go theorems (and their evasion) for compactifications with fluxes. We analyse the resulting four-dimensional effective theories for Calabi-Yau and Calabi-Yau orientifold compactifications, concentrating on the flux-induced superpotentials. We discuss the generic mechanism of moduli stabilization and illustrate with two examples: the conifold in IIB and a T{sup 6} /(Z{sub 3} x Z{sub 3}) torus in IIA. We finish by studying the effective action and flux vacua for generalized geometries in the context of generalized complex geometry.

  10. Nitrous oxide and methane fluxes in six different land use systems in the Peruvian Amazon

    Science.gov (United States)

    Palm, C. A.; Alegre, J. C.; Arevalo, L.; Mutuo, P. K.; Mosier, A. R.; Coe, R.

    2002-12-01

    The contribution of different land-use systems in the humid tropics to increasing atmospheric trace gases has focused on forests, pastures, and crops with few measurements from managed, tree-based systems that dominate much of the landscape. This study from the Peruvian Amazon includes monthly nitrous oxide and methane fluxes from two cropping systems, three tree-based systems, and a 23-year secondary forest control. Average N2O fluxes from the cropping systems were two to three times higher than the secondary forest control (9.1 μg N m-2 h-1), while those of the tree-based systems were similar to the secondary forest. Increased fluxes in the cropping systems were attributed to N fertilization, while fluxes from the tree-based systems were related to litterfall N. Average CH4 consumption was reduced by up to half that of the secondary forest (-30.0 μg C m-2 h-1) in the tree-based and low-input cropping systems. There was net CH4 production in the high-input cropping system. This switch to net production was a result of increased bulk density and increased soil respiration resulting in anaerobic conditions. Reduced rates of N2O emissions, similar CH4 consumption, and high C sequestration rates in these tree-based systems compared with mature forests, coupled with the large area of these systems in the humid tropics, may partially offset the past effects of deforestation on increased atmospheric trace gas concentrations. In contrast, cropping systems with higher N2O emissions, substantially reduced CH4 consumption or even net CH4 emissions, and little C sequestration exacerbate those effects.

  11. Testing of research reactor fuel in the high flux reactor (Petten)

    International Nuclear Information System (INIS)

    Guidez, J.; Markgraf, J.W.; Sordon, G.; Wijtsma, F.J.; Thijssen, P.J.M.; Hendriks, J.A.

    1999-01-01

    The two types of fuel most frequently used by the main research reactors are metallic: highly enriched uranium (>90%) and silicide low enriched uranium ( 3 . However, a need exists for research on new reactor fuel. This would permit some plants to convert without losses in flux or in cycle length and would allow new reactor projects to achieve higher possibilities especially in fluxes. In these cases research is made either on silicide with higher density, or on other types of fuel (UMo, etc.). In all cases when new fuel is proposed, there is a need, for safety reasons, to test it, especially regarding the mechanical evolution due to burn-up (swelling, etc.). Initially, such tests are often made with separate plates, but lately, using entire elements. Destructive examinations are often necessary. For this type of test, the High Flux Reactor, located in Petten (The Netherlands) has many specific advantages: a large core, providing a variety of interesting positions with high fluence rate; a downward coolant flow simplifies the engineering of the device; there exists easy access with all handling possibilities to the hot-cells; the high number of operating days (>280 days/year), together with the high flux, gives a possibility to reach quickly the high burn-up needs; an experienced engineering department capable of translating specific requirements to tailor-made experimental devices; a well equipped hot-cell laboratory on site to perform all necessary measurements (swelling, γ-scanning, profilometry) and all destructive examinations. In conclusion, the HFR reactor readily permits experimental research on specific fuels used for research reactors with all the necessary facilities on the Petten site. (author)

  12. Potentials and challenges associated with automated closed dynamic chamber measurements of soil CO2 fluxes

    Science.gov (United States)

    Görres, Carolyn-Monika; Kammann, Claudia; Ceulemans, Reinhart

    2015-04-01

    Soil respiration fluxes are influenced by natural factors such as climate and soil type, but also by anthropogenic activities in managed ecosystems. As a result, soil CO2 fluxes show a large intra- and interannual as well as intra- and intersite variability. Most of the available soil CO2 flux data giving insights into this variability have been measured with manually closed static chambers, but technological advances in the past 15 years have also led to an increased use of automated closed chamber systems. The great advantage of automated chambers in comparison to manually operated chambers is the higher temporal resolution of the flux data. This is especially important if we want to better understand the effects of short-term events, e.g. fertilization or heavy rainfall, on soil CO2 flux variability. However, the chamber method is an invasive measurement method which can potentially alter soil CO2 fluxes and lead to biased measurement results. In the peer-reviewed literature, many papers compare the field performance and results of different closed static chamber designs, or compare manual chambers with automated chamber systems, to identify potential biases in CO2 flux measurements, and thus help to reduce uncertainties in the flux data. However, inter-comparisons of different automated closed dynamic chamber systems are still lacking. Here we are going to present a field comparison of the most-cited automated chamber system, the LI-8100A Automated Soil Flux System, with the also commercially available Greenhouse Gas Monitoring System AGPS. Both measurement systems were installed side by side at a recently harvested poplar bioenergy plantation (POPFULL, http://uahost.uantwerpen.be/popfull/) from April 2014 until August 2014. The plantation provided optimal comparison conditions with a bare field situation after the harvest and a regrowing canopy resulting in a broad variety of microclimates. Furthermore, the plantation was planted in a double-row system with

  13. Heat Flux Instrumentation Laboratory (HFIL)

    Data.gov (United States)

    Federal Laboratory Consortium — Description: The Heat Flux Instrumentation Laboratory is used to develop advanced, flexible, thin film gauge instrumentation for the Air Force Research Laboratory....

  14. maximum neutron flux at thermal nuclear reactors

    International Nuclear Information System (INIS)

    Strugar, P.

    1968-10-01

    Since actual research reactors are technically complicated and expensive facilities it is important to achieve savings by appropriate reactor lattice configurations. There is a number of papers, and practical examples of reactors with central reflector, dealing with spatial distribution of fuel elements which would result in higher neutron flux. Common disadvantage of all the solutions is that the choice of best solution is done starting from the anticipated spatial distributions of fuel elements. The weakness of these approaches is lack of defined optimization criteria. Direct approach is defined as follows: determine the spatial distribution of fuel concentration starting from the condition of maximum neutron flux by fulfilling the thermal constraints. Thus the problem of determining the maximum neutron flux is solving a variational problem which is beyond the possibilities of classical variational calculation. This variational problem has been successfully solved by applying the maximum principle of Pontrjagin. Optimum distribution of fuel concentration was obtained in explicit analytical form. Thus, spatial distribution of the neutron flux and critical dimensions of quite complex reactor system are calculated in a relatively simple way. In addition to the fact that the results are innovative this approach is interesting because of the optimization procedure itself [sr

  15. Flux motion and dissipation in high temperature superconductors

    International Nuclear Information System (INIS)

    Tinkham, M.

    1991-01-01

    Two quite different motivations spark the study of flux motion and resistance in the new high-temperature superconductors. Achievement of usefully low resistance at usefully large current densities is the key to most practical applications, but conceptual understanding of the idealized resistive behavior in the O current limit motivates much theoretical work. Some analyses emphasize the pinning of individual flux lines to inhomogeneities in the underlying material; others emphasize the collective aspects of the interacting flux lines, whether liquid, solid, crystalline, or glassy; still others emphasize the concept of percolative Josephson coupling between grains. In this paper an overview is given of these various approaches, their interrelation, and the experiment evidence, including some new results on flux motion in large SNS arrays, treated as a model system

  16. Plasmas fluxes to surfaces for an oblique magnetic field

    International Nuclear Information System (INIS)

    Pitcher, C.S.; Stangeby, P.C.; Elder, J.D.; Bell, M.G.; Kilpatrick, S.J.; Manos, D.M.; Medley, S.S.; Owens, D.K.; Ramsey, A.T.; Ulrickson, M.

    1992-07-01

    The poloidal and toroidal spatial distributions of D α , He I and C II emission have been obtained in the vicinity of the TFTR bumper limiter and are compared with models of ion flow to the surface. The distributions are found not to agree with a model (the ''Cosine'' model) which determines the incident flux density using only the parallel fluxes in the scrape-off layer and the projected area of the surface perpendicular to the field lines. In particular, the Cosine model is not able to explain the significant fluxes observed at locations on the surface which are oblique to the magnetic field. It is further shown that these fluxes cannot be explained by the finite Larmor radius of impinging ions. Finally, it is demonstrated, with the use of Monte Carlo codes, that the distributions can be explained by including both parallel and cross-field transport onto the limiter surface

  17. Superconducting coil configurations, with low flux leakage, for energy storage

    International Nuclear Information System (INIS)

    Vincent-Viry, O.; Mailfert, A.; Trassart, D.

    2001-01-01

    This paper presents two original types of SMES structures for energy storage. These two groups of SMES structures proceeded from an ideal structure: the full toroid, are modeled by the use of purely surface current densities. Their main advantage is to present no flux leakage, they give then satisfactory solution to the problem of energy storage. (orig.)

  18. Plastic strain and flux jumps in hard and composite superconductors

    International Nuclear Information System (INIS)

    Maksimov, I.L.; Mints, R.G.

    1981-01-01

    A study is made into the effect of the critical current density dependence upon the value of plastic strain on the critical state stability in hard and composite superconductors under conditions of plastic yield of the material. Criteria of the critical state stability relative to the jointly developing magnetic flux jumps and plastic strain jerks, are found. (author)

  19. Nonlinear performance characteristics of flux-switching PM motors

    NARCIS (Netherlands)

    Ilhan, E.; Kremers, M.F.J.; Motoasca, T.E.; Paulides, J.J.H.; Lomonova, E.

    2013-01-01

    Nonlinear performance characteristics of 3-phase flux-switching permanent magnet motors (FSPM) are overviewed. These machines show advantages of a robust rotor structure and a high energy density. Research on the FSPM is predominated by topics such as modeling and machine comparison, with little

  20. KoFlux: Korean Regional Flux Network in AsiaFlux

    Science.gov (United States)

    Kim, J.

    2002-12-01

    AsiaFlux, the Asian arm of FLUXNET, held the Second International Workshop on Advanced Flux Network and Flux Evaluation in Jeju Island, Korea on 9-11 January 2002. In order to facilitate comprehensive Asia-wide studies of ecosystem fluxes, the meeting launched KoFlux, a new Korean regional network of long-term micrometeorological flux sites. For a successful assessment of carbon exchange between terrestrial ecosystems and the atmosphere, an accurate measurement of surface fluxes of energy and water is one of the prerequisites. During the 7th Global Energy and Water Cycle Experiment (GEWEX) Asian Monsoon Experiment (GAME) held in Nagoya, Japan on 1-2 October 2001, the Implementation Committee of the Coordinated Enhanced Observing Period (CEOP) was established. One of the immediate tasks of CEOP was and is to identify the reference sites to monitor energy and water fluxes over the Asian continent. Subsequently, to advance the regional and global network of these reference sites in the context of both FLUXNET and CEOP, the Korean flux community has re-organized the available resources to establish a new regional network, KoFlux. We have built up domestic network sites (equipped with wind profiler and radiosonde measurements) over deciduous and coniferous forests, urban and rural rice paddies and coastal farmland. As an outreach through collaborations with research groups in Japan, China and Thailand, we also proposed international flux sites at ecologically and climatologically important locations such as a prairie on the Tibetan plateau, tropical forest with mixed and rapid land use change in northern Thailand. Several sites in KoFlux already begun to accumulate interesting data and some highlights are presented at the meeting. The sciences generated by flux networks in other continents have proven the worthiness of a global array of micrometeorological flux towers. It is our intent that the launch of KoFlux would encourage other scientists to initiate and

  1. Fluxon density waves in long Josephson junctions

    DEFF Research Database (Denmark)

    Olsen, O. H.; Ustinov, A. V.; Pedersen, Niels Falsig

    1993-01-01

    Numerical simulations of the multiple fluxon dynamics stimulated by an external oscillating force applied at a boundary of a long Josephson junction are presented. The calculated IV characteristics agree well with a recent experimental observation of rf-induced satellite flux-flow steps. The volt...... density waves....

  2. Field experiment on 222Rn flux from reclaimed uranium tailings

    International Nuclear Information System (INIS)

    Hinton, T.G.

    1983-01-01

    Design and construction techniques are described for a 1.6 ha experimental uranium mill tailings reclamation plot. A passive, activated charcoal device was developed and tested for measurements of radon flux. Experiments on radon flux versus overburden depth showed that tailings covered with 1.5 m of revegetated or 0.3 m of bare overburden had exhalation rates comparable to background. Vegetated subplots exhibited a significantly higher (often an order of magnitude) flux than the bare subplots. Results on the variation of flux over time did not reveal any definitive patterns, possibly due to the high variability among replicates. A positive correlation was demonstrated between precipitation and radon flux. This is discussed in detail and possibly explained by the increase in water content of the micropores within the tailings, which increases the emanation coefficient without adversely effecting the diffusion coefficient of the overburden. 30 references, 7 figures, 3 tables

  3. Neutron flux stabilization in the NG-150 neutron generators

    International Nuclear Information System (INIS)

    Kuz'min, L.E.; Makarov, S.A.; Pronman, I.M.

    1986-01-01

    Problem of metal tritium target lifetime increase and neutron flux stabilization in the NG-150 neutron generators is studied. Possibility on neutron flux stabilization using the mass analyzer for low-angle (4 deg and 41 deg) mass separation of a beam in thre components, which fall on a target simultaneously, is confirmed experimentally. Basic generator parameters are: accelerating voltage of 150 kV, total beam current on a target of 1.5 mA, beam current density of 0.3-1.6 mA/cm 2 , beam diameter of 8 mm. The initial neutron flux on the targets of 0.73 mg/cm 2 thick constituted 1.1x10 11 ssup(-1). The neutron flux monitoring was accomplished from recoil proton recording by a plastic scintillator. Flux decrease by more than 5% served as a signel for measuring mass analyzer magnetic field providing beam displacement on a target and restoration of the given flux. The NG-150 generator neutron flux stabilization was attained during 2h

  4. Super liquid density target designs

    International Nuclear Information System (INIS)

    Pan, Y.L.; Bailey, D.S.

    1976-01-01

    The success of laser fusion depends on obtaining near isentropic compression of fuel to very high densities and igniting this fuel. To date, the results of laser fusion experiments have been based mainly on the exploding pusher implosion of fusion capsules consisting of thin glass microballoons (wall thickness of less than 1 micron) filled with low density DT gas (initial density of a few mg/cc). Maximum DT densities of a few tenths of g/cc and temperatures of a few keV have been achieved in these experiments. We will discuss the results of LASNEX target design calculations for targets which: (a) can compress fuel to much higher densities using the capabilities of existing Nd-glass systems at LLL; (b) allow experimental measurement of the peak fuel density achieved

  5. Aspects of six-dimensional flux compactifications

    Energy Technology Data Exchange (ETDEWEB)

    Dierigl, Markus

    2017-08-15

    In this thesis we investigate various aspects of flux compactifications in six-dimensional quantum field theories. After introducing the internal geometries, i.e. the two-dimensional torus T{sup 2} and one of its orbifolds T{sup 2}/Z{sub 2}, we classify possible gauge backgrounds including continuous and discrete Wilson lines with emphasis on a non-vanishing flux density. An operator analogy with the quantum harmonic oscillator allows for an explicit derivation of the mode functions of charged fields and demonstrates the advantage of our interpretation of discrete Wilson lines in terms of localized fractional gauge fluxes. We then derive a globally supersymmetric action which captures the D-term supersymmetry breaking induced by the internal magnetic field and reproduces the Landau level mass spectrum of the charged four-dimensional degrees of freedom. In this context we show that, even though supersymmetry is broken at the compactification scale, the inclusion of the whole tower of charged states leads to vanishing quantum corrections for the Wilson line effective potential on T{sup 2}. This result is supported by a symmetry breaking argument in which the Wilson line appears as a Goldstone boson. After that, we additionally include gravitational effects within a supergravity effective action of the lightest modes in four dimensions. The dynamics of the moduli fields arising after compactification can be encoded in the setup of N=1 supergravity augmented with anomaly cancellation by the Green-Schwarz mechanism. This leads to a non-trivial transformation behavior for two axion fields under gauge variations in the low-energy effective action. As an application, we discuss an SO(10) x U(1) grand unified theory which uses the multiplicity of fermionic zero modes in the flux background to induce the number of matter generations. Finally, we investigate a novel mechanism for generating de Sitter vacua in N=1 supergravity based on a flux-induced positive definite D

  6. Aspects of six-dimensional flux compactifications

    International Nuclear Information System (INIS)

    Dierigl, Markus

    2017-08-01

    In this thesis we investigate various aspects of flux compactifications in six-dimensional quantum field theories. After introducing the internal geometries, i.e. the two-dimensional torus T"2 and one of its orbifolds T"2/Z_2, we classify possible gauge backgrounds including continuous and discrete Wilson lines with emphasis on a non-vanishing flux density. An operator analogy with the quantum harmonic oscillator allows for an explicit derivation of the mode functions of charged fields and demonstrates the advantage of our interpretation of discrete Wilson lines in terms of localized fractional gauge fluxes. We then derive a globally supersymmetric action which captures the D-term supersymmetry breaking induced by the internal magnetic field and reproduces the Landau level mass spectrum of the charged four-dimensional degrees of freedom. In this context we show that, even though supersymmetry is broken at the compactification scale, the inclusion of the whole tower of charged states leads to vanishing quantum corrections for the Wilson line effective potential on T"2. This result is supported by a symmetry breaking argument in which the Wilson line appears as a Goldstone boson. After that, we additionally include gravitational effects within a supergravity effective action of the lightest modes in four dimensions. The dynamics of the moduli fields arising after compactification can be encoded in the setup of N=1 supergravity augmented with anomaly cancellation by the Green-Schwarz mechanism. This leads to a non-trivial transformation behavior for two axion fields under gauge variations in the low-energy effective action. As an application, we discuss an SO(10) x U(1) grand unified theory which uses the multiplicity of fermionic zero modes in the flux background to induce the number of matter generations. Finally, we investigate a novel mechanism for generating de Sitter vacua in N=1 supergravity based on a flux-induced positive definite D-term potential. The

  7. Arabidopsis thaliana Ei-5: Minor Vein Architecture Adjustment Compensates for Low Vein Density in Support of Photosynthesis.

    Science.gov (United States)

    Stewart, Jared J; Polutchko, Stephanie K; Demmig-Adams, Barbara; Adams, William W

    2018-01-01

    An Arabidopsis thaliana accession with naturally low vein density, Eifel-5 (Ei-5), was compared to Columbia-0 (Col-0) with respect to rosette growth, foliar vein architecture, photosynthesis, and transpiration. In addition to having to a lower vein density, Ei-5 grew more slowly, with significantly lower rates of rosette expansion, but had similar capacities for photosynthetic oxygen evolution on a leaf area basis compared to Col-0. The individual foliar minor veins were larger in Ei-5, with a greater number of vascular cells per vein, compared to Col-0. This compensation for low vein density resulted in similar values for the product of vein density × phloem cell number per minor vein in Ei-5 and Col-0, which suggests a similar capacity for foliar sugar export to support similar photosynthetic capacities per unit leaf area. In contrast, the product of vein density × xylem cell number per minor vein was significantly greater in Ei-5 compared to Col-0, and was associated not only with a higher ratio of water-transporting tracheary elements versus sugar-transporting sieve elements but also significantly higher foliar transpiration rates per leaf area in Ei-5. In contrast, previous studies in other systems had reported higher ratios of tracheary to sieve elements and higher transpiration rate to be associated with higher - rather than lower - vein densities. The Ei-5 accession thus further underscores the plasticity of the foliar vasculature by illustrating an example where a higher ratio of tracheary to sieve elements is associated with a lower vein density. Establishment of the Ei-5 accession, with a low vein density but an apparent overcapacity for water flux through the foliar xylem network, may have been facilitated by a higher level of precipitation in its habitat of origin compared to that of the Col-0 accession.

  8. From elementary flux modes to elementary flux vectors: Metabolic pathway analysis with arbitrary linear flux constraints

    Science.gov (United States)

    Klamt, Steffen; Gerstl, Matthias P.; Jungreuthmayer, Christian; Mahadevan, Radhakrishnan; Müller, Stefan

    2017-01-01

    Elementary flux modes (EFMs) emerged as a formal concept to describe metabolic pathways and have become an established tool for constraint-based modeling and metabolic network analysis. EFMs are characteristic (support-minimal) vectors of the flux cone that contains all feasible steady-state flux vectors of a given metabolic network. EFMs account for (homogeneous) linear constraints arising from reaction irreversibilities and the assumption of steady state; however, other (inhomogeneous) linear constraints, such as minimal and maximal reaction rates frequently used by other constraint-based techniques (such as flux balance analysis [FBA]), cannot be directly integrated. These additional constraints further restrict the space of feasible flux vectors and turn the flux cone into a general flux polyhedron in which the concept of EFMs is not directly applicable anymore. For this reason, there has been a conceptual gap between EFM-based (pathway) analysis methods and linear optimization (FBA) techniques, as they operate on different geometric objects. One approach to overcome these limitations was proposed ten years ago and is based on the concept of elementary flux vectors (EFVs). Only recently has the community started to recognize the potential of EFVs for metabolic network analysis. In fact, EFVs exactly represent the conceptual development required to generalize the idea of EFMs from flux cones to flux polyhedra. This work aims to present a concise theoretical and practical introduction to EFVs that is accessible to a broad audience. We highlight the close relationship between EFMs and EFVs and demonstrate that almost all applications of EFMs (in flux cones) are possible for EFVs (in flux polyhedra) as well. In fact, certain properties can only be studied with EFVs. Thus, we conclude that EFVs provide a powerful and unifying framework for constraint-based modeling of metabolic networks. PMID:28406903

  9. Device for measuring fission product density

    International Nuclear Information System (INIS)

    Kaneda, Mitsunori.

    1980-01-01

    Purpose: To determine the fission product density of xenon or the like and enable measurement of real time of fission product density in a reactor by calculating the disintegration and annihilation of the fission product on the basis of neutron detected output. Constitution: The neutron flux in a reactor is detected by a detector, and applied to first and second density calculators. Second fission product density signal of xenon or the like outputted from first device is again inputted to the device to form an annihilation signal due to disintegration to determine the present density of the second fission product of xenon or the like corresponding to the decrease of the neutron due to the poison of xeron or the like. Similarly, second device determines the first fission product density of iodine or the like. (Sekiya, K.)

  10. The Maximum Flux of Star-Forming Galaxies

    Science.gov (United States)

    Crocker, Roland M.; Krumholz, Mark R.; Thompson, Todd A.; Clutterbuck, Julie

    2018-04-01

    The importance of radiation pressure feedback in galaxy formation has been extensively debated over the last decade. The regime of greatest uncertainty is in the most actively star-forming galaxies, where large dust columns can potentially produce a dust-reprocessed infrared radiation field with enough pressure to drive turbulence or eject material. Here we derive the conditions under which a self-gravitating, mixed gas-star disc can remain hydrostatic despite trapped radiation pressure. Consistently taking into account the self-gravity of the medium, the star- and dust-to-gas ratios, and the effects of turbulent motions not driven by radiation, we show that galaxies can achieve a maximum Eddington-limited star formation rate per unit area \\dot{Σ }_*,crit ˜ 10^3 M_{⊙} pc-2 Myr-1, corresponding to a critical flux of F*, crit ˜ 1013L⊙ kpc-2 similar to previous estimates; higher fluxes eject mass in bulk, halting further star formation. Conversely, we show that in galaxies below this limit, our one-dimensional models imply simple vertical hydrostatic equilibrium and that radiation pressure is ineffective at driving turbulence or ejecting matter. Because the vast majority of star-forming galaxies lie below the maximum limit for typical dust-to-gas ratios, we conclude that infrared radiation pressure is likely unimportant for all but the most extreme systems on galaxy-wide scales. Thus, while radiation pressure does not explain the Kennicutt-Schmidt relation, it does impose an upper truncation on it. Our predicted truncation is in good agreement with the highest observed gas and star formation rate surface densities found both locally and at high redshift.

  11. Size scaling effects on the particle density fluctuations in confined plasmas

    International Nuclear Information System (INIS)

    Vazquez, Federico; Markus, Ferenc

    2009-01-01

    In this paper, memory and nonlocal effects on fluctuating mass diffusion are addressed in the context of fusion plasmas. Nonlocal effects are included by considering a diffusivity coefficient depending on the size of the container in the transverse direction to the applied magnetic field. It is obtained by resorting to the general formulation of the extended version of irreversible thermodynamics in terms of the higher order dissipative fluxes. The developed model describes two different types of the particle density time correlation function. Both have been observed in tokamak and nontokamak devices. These two kinds of time correlation function characterize the wave and the diffusive transport mechanisms of particle density perturbations. A transition between them is found, which is controlled by the size of the container. A phase diagram in the (L,2π/k) space describes the relation between the dynamics of particle density fluctuations and the size L of the system together with the oscillating mode k of the correlation function.

  12. Methane Flux of Amazonian Peatland Ecosystems: Large Ecosystem Fluxes with Substantial Contribution from Palm (maritia Flexuosa) STEM Emissions

    Science.gov (United States)

    Van Haren, J. L. M.; Cadillo-Quiroz, H.

    2015-12-01

    Methane (CH4) emissions through plants have long been known in wetlands. However, most measurements have focused on stem tops and leaves. Recently, measurements at the lower parts of stems have shown that stem emissions can exceed soil CH4 emissions in Asian peatlands (Pangala et al. 2013). The addition of stem fluxes to soil fluxes for total ecosystem fluxes has the potential to bridge the discrepancy between modeled to measured and bottom-up to top-down flux estimates. Our measurements in peatlands of Peru show that especially Mauritia flexuosa, a palm species, can emit very large quantities of CH4, although most trees emitted at least some CH4. We used flexible stem chambers to adapt to stems of any size above 5cm in diameter. The chambers were sampled in closed loop with a Gasmet DX4015 for flux measurements, which lasted ~5 minutes after flushing with ambient air. We found that M. flexuosa stem fluxes decrease with height along the stem and were positively correlated with soil fluxes. Most likely CH4 is transported up the stem with the xylem water. Measured M. flexuosa stem fluxes below 1.5m averaged 11.2±1.5 mg-C m-2 h-1 (±95% CI) with a maximum of 123±3.5 mg-C m-2 h-1 (±SE), whereas soil fluxes averaged 6.7±1.7 mg-C m-2 h-1 (±95% CI) with a maximum of 31.6±0.4 mg-C m-2 h-1 (±SE). Significant CH4 fluxes were measured up to 5 m height along the stems. Combined with the high density of ~150 M. flexuosa individuals per hectare in these peatlands and the consistent diameter of ~30cm, the high flux rates add ~20% to the soil flux. With anywhere between 1 and 5 billion M. flexuosa stems across Amazon basin wetlands, stem fluxes from this palm species could represent a major addition to the overall Amazon basin CH4 flux.

  13. Flux trapping in superconducting cavities

    International Nuclear Information System (INIS)

    Vallet, C.; Bolore, M.; Bonin, B.; Charrier, J.P.; Daillant, B.; Gratadour, J.; Koechlin, F.; Safa, H.

    1992-01-01

    The flux trapped in various field cooled Nb and Pb samples has been measured. For ambient fields smaller than 3 Gauss, 100% of the flux is trapped. The consequences of this result on the behavior of superconducting RF cavities are discussed. (author) 12 refs.; 2 figs

  14. Squeezing Flux Out of Fat

    DEFF Research Database (Denmark)

    Gonzalez-Franquesa, Alba; Patti, Mary-Elizabeth

    2018-01-01

    Merging transcriptomics or metabolomics data remains insufficient for metabolic flux estimation. Ramirez et al. integrate a genome-scale metabolic model with extracellular flux data to predict and validate metabolic differences between white and brown adipose tissue. This method allows both metab...

  15. Data Acquisition and Flux Calculations

    DEFF Research Database (Denmark)

    Rebmann, C.; Kolle, O; Heinesch, B

    2012-01-01

    In this chapter, the basic theory and the procedures used to obtain turbulent fluxes of energy, mass, and momentum with the eddy covariance technique will be detailed. This includes a description of data acquisition, pretreatment of high-frequency data and flux calculation....

  16. The Solar-flux Third Granulation Signature

    Science.gov (United States)

    Gray, David F.; Oostra, Benjamin

    2018-01-01

    The velocity shifts of spectral lines as a function of line strength, so-called the third signature of granulation, are investigated using three published solar-flux atlases. We use flux atlases because we wish to treat the Sun as a star, against which stellar observations can be compared and judged. The atlases are critiqued and compared to the lower-resolution observations taken with the Elginfield stellar spectrograph. Third-signature plots are constructed for the 6020–6340 Å region. No dependence on excitation potential or wavelength is found over this wavelength span. The shape of the plots from the three solar atlases is essentially the same, with rms line-core velocity differences of 30–35 m s‑1. High-resolution atlas data are degraded to the level of the Elginfield spectrograph and compared to direct observations taken with that spectrograph. The line-core velocities show good agreement, with rms differences of 38 m s‑1. A new standard curve is derived and compared with the previously published one. Only small differences in shape are found, but a significant (+97 m s‑1) change in the zero point is indicated. The bisector of the Fe I 6253 line is mapped onto the third-signature plots and flux deficits are derived, which measure the granule/lane flux imbalance. The lower spectral resolution lowers the flux deficit area slightly and moves the peak of the deficit 0.3–0.5 km s‑1 toward higher velocities. These differences, while significant, are not large compared to measurement errors for stellar data.

  17. Turbulent flux and the diffusion of passive tracers in electrostatic turbulence

    DEFF Research Database (Denmark)

    Basu, R.; Jessen, T.; Naulin, V.

    2003-01-01

    The connection between the diffusion of passive tracer particles and the anomalous turbulent flux in electrostatic drift-wave turbulence is investigated by direct numerical solutions of the 2D Hasegawa-Wakatani equations. The probability density functions for the point-wise and flux surface...

  18. Effects of magnetizing on flux pinning force for sintered YBCO superconductor

    International Nuclear Information System (INIS)

    Ding, S.Y.; Yan, J.L.; Yu, Z.; Shi, K.X.; Tong, H.W.; Qiu, L.

    1989-01-01

    It is shown that magnitude and course of magnetizing field influence magnetization and transport current. Effective flux pinning force density with two types is extracted by an iterative procedure based on the critical state equation. One of the types is attributed to the weak links and the other is considered to be resulted from the intragrain flux pinning centers

  19. Solar proton fluxes since 1956

    International Nuclear Information System (INIS)

    Reedy, R.C.

    1977-01-01

    The fluxes of protons emitted during solar flares since 1956 were evaluated. The depth-versus-activity profiles of 56 Co in several lunar rocks are consistent with the solar-proton fluxes detected by experiments on several satellites. Only about 20% of the solar-proton-induced activities of 22 Na and 55 Fe in lunar rocks from early Apollo missions were produced by protons emitted from the sun during solar cycle 20 (1965--1975). The depth-versus-activity data for these radionuclides in several lunar rocks were used to determine the fluxes of protons during solar cycle 19 (1954--1964). The average proton fluxes for cycle 19 are about five times those for both the last million years and for cycle 20. These solar-proton flux variations correlate with changes in sunspot activity

  20. A Novel Approach to the Design of Axial-Flux Switched-Reluctance Motors

    Directory of Open Access Journals (Sweden)

    Tim Lambert

    2015-03-01

    Full Text Available This paper presents the design of a new axial-flux switched-reluctance motor (AFSRM topology for in-wheel drive vehicle applications. The features of the topology include a short flux path and an outer-rotor configuration. The proposed topology also uses a sintered-lamellar soft magnetic composite core material, and permits displacement of the rotor along the suspension axis, which reduces damage to the stator caused by impacts and vibrations. The combination of these features makes this new topology competitive with other in-wheel motors in regard to torque density, durability, and cost. To describe the behaviour of the topology, a model of the topology is developed using a new integral inductance function. That model is used to select the design parameters of an 8/6 AFSRM, for which a fuzzy controller is also developed to control the phase current. Several simulations of the 8/6 AFSRM are performed to calculate its energy conversion efficiency, thermal performance, and torque density, and results indicate that the new AFSRM has a higher energy conversion efficiency, and can produce more torque/kg than other switched-reluctance motors used for in-wheel drive vehicle applications.

  1. Fractional flux excitations and flux creep in a superconducting film

    International Nuclear Information System (INIS)

    Lyuksyutov, I.F.

    1995-01-01

    We consider the transport properties of a modulated superconducting film in a magnetic field parallel to the film. Modulation can be either intrinsic, due to the layered structure of the high-T c superconductors, or artificial, e.g. due to thickness modulation. This system has an infinite set ( >) of pinned phases. In the pinned phase the excitation of flux loops with a fractional number of flux quanta by the applied current j results in flux creep with a generated voltage V ∝ exp[-jo/j[. (orig.)

  2. Monte Carlo surface flux tallies

    International Nuclear Information System (INIS)

    Favorite, Jeffrey A.

    2010-01-01

    Particle fluxes on surfaces are difficult to calculate with Monte Carlo codes because the score requires a division by the surface-crossing angle cosine, and grazing angles lead to inaccuracies. We revisit the standard practice of dividing by half of a cosine 'cutoff' for particles whose surface-crossing cosines are below the cutoff. The theory behind this approximation is sound, but the application of the theory to all possible situations does not account for two implicit assumptions: (1) the grazing band must be symmetric about 0, and (2) a single linear expansion for the angular flux must be applied in the entire grazing band. These assumptions are violated in common circumstances; for example, for separate in-going and out-going flux tallies on internal surfaces, and for out-going flux tallies on external surfaces. In some situations, dividing by two-thirds of the cosine cutoff is more appropriate. If users were able to control both the cosine cutoff and the substitute value, they could use these parameters to make accurate surface flux tallies. The procedure is demonstrated in a test problem in which Monte Carlo surface fluxes in cosine bins are converted to angular fluxes and compared with the results of a discrete ordinates calculation.

  3. Theory of redeposition of sputtered flux on to surface asperities

    International Nuclear Information System (INIS)

    Belson, J.; Wilson, I.H.

    1981-01-01

    This paper models the topographical evolution of features on amorphous surfaces under ion bombardment. Specifically, evolution due to accretion of material sputtered from areas adjacent to a feature has been investigated in terms of the flux density redeposited on to an arbitrary profile y = f(xi) from a linear emitter. Analytical solutions have been found for the early ( first burst ) evolution of linear and sinusoidal surface features in cases where the emitter radiates isotropically or anisotropically (cosine law) from each point of its length. The predictions of models based on these two types of emitter are compared. Both types produce enhanced deposition near the foot of a linear slope but the effect is much greater for isotropic emission. Above the foot of a linear slope there is a point beyond which the redeposition due to an anisotropic emitter is greater than that due to an isotropic emitter of identical luminance. For a 90 0 slope (step or groove of rectangular section) the point is about 0.4 times the emitter length (i.e. 0.4 x groove width) above the base. Sinusoidal asperities which are present in a high surface density are expected to receive significant redeposited flux only near their bases. By contrast, widely separated asperities would receive flux over almost all or their profiles. In this latter situation the magnitude of the redeposited flux density is found to be relatively insensitive to position on a profile. (orig.)

  4. Variability of the Lyman alpha flux with solar activity

    International Nuclear Information System (INIS)

    Lean, J.L.; Skumanich, A.

    1983-01-01

    A three-component model of the solar chromosphere, developed from ground based observations of the Ca II K chromospheric emission, is used to calculate the variability of the Lyman alpha flux between 1969 and 1980. The Lyman alpha flux at solar minimum is required in the model and is taken as 2.32 x 10 11 photons/cm 2 /s. This value occurred during 1975 as well as in 1976 near the commencement of solar cycle 21. The model predicts that the Lyman alpha flux increases to as much as 5 x 10 11 photons/cm 2 /s at the maximum of the solar cycle. The ratio of the average fluxes for December 1979 (cycle maximum) and July 1976 (cycle minimum) is 1.9. During solar maximum the 27-day solar rotation is shown to cause the Lyman alpha flux to vary by as much as 40% or as little as 5%. The model also shows that the Lyman alpha flux varies over intermediate time periods of 2 to 3 years, as well as over the 11-year sunspot cycle. We conclude that, unlike the sunspot number and the 10.7-cm radio flux, the Lyman alpha flux had a variability that was approximately the same during each of the past three cycles. Lyman alpha fluxes calculated by the model are consistent with measurements of the Lyman alpha flux made by 11 of a total of 14 rocket experiments conducted during the period 1969--1980. The model explains satisfactorily the absolute magnitude, long-term trends, and the cycle variability seen in the Lyman alpha irradiances by the OSO 5 satellite experiment. The 27-day variability observed by the AE-E satellite experiment is well reproduced. However, the magntidue of the AE-E 1 Lyman alpha irradiances are higher than the model calculations by between 40% and 80%. We suggest that the assumed calibration of the AE-E irradiances is in error

  5. Performance management and academic workload in higher ...

    African Journals Online (AJOL)

    The South African Higher Education system is in a state of rapid flux. Various factors are rendering education vulnerable to destructive influences. It has become imperative for academic managers to ensure that academic staff function productively. Management information systems which will generate correct information as ...

  6. Modelling of interplanetary pickup ion fluxes and relevance for LISM parameters

    International Nuclear Information System (INIS)

    Fahr, H.J.; Rucinski, D.

    1989-01-01

    It has been known for many years that neutral interstellar atoms enter the solar system from the upwind side and penetrate deep into the inner heliosphere. Helium atoms, in particular, advance towards very small solar distances before they are ionized and then again convected as He - pickup ions outwards with the solar wind. Since these ions were recently detected in space, we concentrate here on calculations of He + production rates and He + fluxes. It is shown that inside 1 a.u., the He - production is essentially determined both by solar e.u.v. photoionization and by electron impact ionization. We calculate He + production rates as a function of space coordinates, taking into account the core-halo structure of the energy distribution of solar wind electrons and their temperature distribution with distance according to relevant solar wind models. For this purpose, a newly developed program to compute He densities was used. In contrast to the production of H + , the He - production rates are found to be higher on the downwind axis than on the upwind axis by a factor of 5. We also determine partial and total He + ion fluxes as a function of solar distance and longitude. It is interesting to note that only the values for total fluxes agree well with the integrated He + fluxes measured by the SULEICA experiment aboard the AMPTE satellite. This indicates that pickup ions under the influence of the intrinsic MHD wave turbulence in the solar wind change their primary seed distribution function by rapid pitch-angle scattering and subsequent adiabatic cooling. To interpret the He + intensity profile along the orbit of the Earth in terms of LISM helium parameters, we point to the need to take into account carefully electron impact ionization in order to prevent misinterpretations. (author)

  7. Critical heat flux of R134A and R245FA in a 2.2 mm circular tube

    Energy Technology Data Exchange (ETDEWEB)

    Tibirica, Cristiano Bigonha; Ribatski, Gherhardt [Universidade de Sao Paulo (EESC/USP), Sao Carlos, SP (Brazil). Escola de Engenharia. Dept. de Engenharia Mecanica], E-mails: bigonha@sc.usp.br, ribatski@sc.usp.br; Szczukiewicz, Sylwia; Thome, John Richard [Ecole Polytechnique Federale de Lausanne (LTCM/EPFL) (Switzerland). Lab. of Heat and Mass Transfer], Emails: sylwia.szczukiewicz@epfl.ch, john.thome@epfl.ch

    2010-07-01

    Critical heat flux (CHF) during flow boiling is generally related to a drastic decrease in the heat transfer coefficient and it is the maximum operational heat flux that can be achieved under safe operation. Due to such a fact, this topic has attracted great attention of the academic society dealing with boiling heat transfer and also in the industrial sector involved with the dissipation of high heat flux densities. In the specific case of high heat flux densities, micro-channel flow boiling is a promising technique for pursuing this objective. The boundary where microscale effects start in flow boiling is still an open issue in the literature and a 3 mm internal diameter (ID) threshold value, as suggested by Kandlikar and Grande (2003) is frequently adopted to characterize this point. Considering the needs for a better understanding of the micro/macro transition, this paper presents new experimental critical heat flux results in saturated flow boiling conditions for a macro/micro-scale tube. The data were obtained in a horizontal 2.20 mm ID stainless steel tube with heating lengths of 361 and 154 mm, R134a and R245fa as working fluids, mass velocities ranging from 100 to 1500 kg/m{sup 2s}, critical heat fluxes from 25 to 300 kW/m2, exit saturation temperatures of 25, 31 and 35 degree C, and critical vapor qualities ranging from 0.55 to 1. The experimental results show that critical heat flux increases with increasing mass velocity and inlet subcooling but decreases with increasing saturation temperature and heated length. The data also indicated a higher CHF for R245fa when compared with R134a at similar conditions. The experimental data were compared against the following CHF predictive methods: Katto and Ohno (1984), Shah (1987), Zhang et al. (2006) and Ong and Thome(2010). Katto and Ohno (1984) and Ong and Thome (2010) best predicted the database with a mean average error smaller than 15%. Both correlations include low and high pressure fluids in their

  8. Increasing the neutron flux study for the TRR-II core design

    International Nuclear Information System (INIS)

    Chen, C.-H.; Yang, J.-T.; Chou, Y.-C.

    1999-01-01

    The maximum unperturbed thermal flux of the originally proposed core design, which is a 6x6 square arrangement with power level of 20 MW and has been presented at the 6th Meeting of IGORR, for the TRR-II reactor is about 2.0x10 14 n/cm 2 -sec. However, it is no longer satisfied the user's requirement, that is, it must reach at least 2.5x10 14 n/cm 2 -sec. In order to enhance the thermal neutron flux, one of the most effective ways is to increase the average power density. Therefore, two new designs with more compact cores are then proposed and studied. One is 5x6 rectangular arrangement with power of 20 MW; the other one is 5x5 square arrangement with power of 16 MW. It is for sure that both core designs can satisfy thermal hydraulic safety limits. The designed parameters related to neutronics are listed and compared fundamentally. According to our calculation, although both cores have similar average power density, the results show that the 5x6/20 MW design has the maximum unperturbed thermal flux in the D 2 O region about 2.7x10 14 n/cm 2 -sec, and the 5x5/16 MW design has 2.5x10 14 n/cm 2 -sec. The maximum thermal flux in the neighborhood of the longer side of the 5x6 core is about 7% higher than the one in the neighborhood of any side of the 5x5 core. This 'long-side effect' gives the 5x6/20 MW core design an advantage of the utilization of the thermal neutron flux in the D 2 O region. In addition, the 5x5 core is also more sensitive to the reactivity change on account of in-core irradiation test facilities. Therefore, under overall considerations the 5x6/20 MW core design is chosen for further detailed design. (author)

  9. Flux creep characteristics in high-temperature superconductors

    International Nuclear Information System (INIS)

    Zeldov, E.; Amer, N.M.; Koren, G.; Gupta, A.; McElfresh, M.W.; Gambino, R.J.

    1990-01-01

    We describe the voltage-current characteristics of YBa 2 Cu 3 O 7-δ epitaxial films within the flux creep model in a manner consistent with the resistive transition behavior. The magnitude of the activation energy, and its temperature and magnetic field dependences, are readily derived from the experimentally observed power law characteristics and show a (1-T/T c ) 3/2 type of behavior near T c . The activation energy is a nonlinear function of the current density and it enables the determination of the shape of the flux line potential well

  10. Magnetic flux periodicities and finite momentum pairing in unconventional superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Loder, Florian

    2009-12-22

    This work contains a thorough study of the magnetic flux periodicity of loops of conventional and unconventional, especially d-wave, superconductors. Although already in 1961, several independent works showed that the flux period of a conventional superconducting loop is the superconducting flux quantum hc/2e, this question has never been investigated deeply for unconventional superconductors. And indeed, we show here that d-wave superconducting loops show a basic flux period of the normal flux quantum hc/e, a property originating from the nodal quasi-particle states. This doubling of the flux periodicity is best visible in the persistent current circulating in the loop, and it affects other properties of the superconductor such as the periodicity of d-wave Josephson junctions. In the second part of this work, the theory of electron pairing with finite center-of-mass momentum, necessary for the description of superconducting loops, is extended to systems in zero magnetic field. We show that even in the field free case, an unconventional pairing symmetry can lead to a superconducting ground state with finite-momentum electron pairs. Such a state has an inhomogeneous charge density and therefore is a basis for the description of coexistence of superconductivity and stripe order. (orig.)

  11. Fast neutron fluxes distribution in Egyptian ilmenite concrete

    International Nuclear Information System (INIS)

    Megahed, R.M.; Abou El-Nasr, T.Z.; Bashter, I.I.

    1978-01-01

    This work is concerned with the study of the distribution of fast neutron fluxes in a new type of heavy concrete made from Egyptian ilmenite ores. The neutron source used was a collimated beam of reactor neutrons emitted from one of the horizontal channels of the ET-RR-1 reactor. Measurements were carried-out using phosphorous activation detectors. Iso-flux curves were represented which give directly the shape and thickness required to attenuate the emitted fast neutron flux to a certain value. The relaxation lengths were also evaluated from the measured data for both disc monodirectional source and infinite plane monodirectional source. The obtained values were compared with that calculated using the derived values of relative number densities and microscopic removal cross-sections of the different constituents. The obtained data show that ilmenite concrete attenuates fast neutron flux more strongly than ordinary concrete. A semiemperical formula was derived to calculate the fast neutron flux at different thicknesses along the beam axis. Another semiemperical formula was also derived to calculate the fast neutron flux in ordinary concrete along the beam axis using the corresponding value in ilmenite concrete

  12. Magnetic flux concentration methods for magnetic energy harvesting module

    Directory of Open Access Journals (Sweden)

    Wakiwaka Hiroyuki

    2013-01-01

    Full Text Available This paper presents magnetic flux concentration methods for magnetic energy harvesting module. The purpose of this study is to harvest 1 mW energy with a Brooks coil 2 cm in diameter from environmental magnetic field at 60 Hz. Because the harvesting power is proportional to the square of the magnetic flux density, we consider the use of a magnetic flux concentration coil and a magnetic core. The magnetic flux concentration coil consists of an air­core Brooks coil and a resonant capacitor. When a uniform magnetic field crossed the coil, the magnetic flux distribution around the coil was changed. It is found that the magnetic field in an area is concentrated larger than 20 times compared with the uniform magnetic field. Compared with the air­core coil, our designed magnetic core makes the harvested energy ten­fold. According to ICNIRP2010 guideline, the acceptable level of magnetic field is 0.2 mT in the frequency range between 25 Hz and 400 Hz. Without the two magnetic flux concentration methods, the corresponding energy is limited to 1 µW. In contrast, our experimental results successfully demonstrate energy harvesting of 1 mW from a magnetic field of 0.03 mT at 60 Hz.

  13. Experimental research on density wave oscillation of steam-water two-phase flow in parallel inclined internally ribbed pipes

    International Nuclear Information System (INIS)

    Gao Feng; Chen Tingkuan; Luo Yushan; Yin Fei; Liu Weimin

    2005-01-01

    At p=3-10 MPa, G=300-600 kg/(m 2 ·s), Δt sub =30-90 degree C, and q=0-190 kW/m 2 , the experiments on steam-water two-phase flow instabilities have been performed. The test sections are parallel inclined internally ribbed pipes with an outer diameter of φ38.1 mm, a wall thinkness of 7.5 mm, a obliquity of 19.5 and a length more than 15 m length. Based on the experimental results, the effects of pressure, mass velocity, inlet subcooling and asymmetrical heat flux on steam-water two-phase flow density wave oscillation were analyzed. The experimental results showed that the flow system were more stable as pressure increased. As an increase in mass velocity, critical heat flux increased but critical steam quality decreased. Inlet subcooling had a monotone effect on density wave oscillation, when inlet subcooling decreased, critical heat flux decreased. Under a certain working condition, critical heat flux on asymmetrically heating parallel pipes is higher than that on symmetrically heating parallel pipes, that means the system with symmetrically heating parallel pips was more stable. (authors)

  14. Influence of the late winter bloom on migrant zooplankton metabolism and its implications on export fluxes

    Science.gov (United States)

    Putzeys, S.; Yebra, L.; Almeida, C.; Bécognée, P.; Hernández-León, S.

    2011-12-01

    Studies on carbon active fluxes due to diel migrants are scarce and critical for carbon flux models and biogeochemical estimates. We studied the temporal variability and vertical distribution of biomass, indices of feeding and respiration of the zooplanktonic community north off the Canary Islands during the end of the late winter bloom, in order to assess vertical carbon fluxes in this area. Biomass distribution during the day presented two dense layers of organisms at 0-200 m and around 500 m, whereas at night, most of the biomass concentrated in the epipelagic layer. The gut pigment flux (0.05-0.18 mgC·m - 2 ·d - 1 ) represented 0.22% of the estimated passive export flux (POC flux) while potential ingestion represented 3.91% of the POC (1.24-3.40 mgC·m - 2 ·d - 1 ). The active respiratory flux (0.50-1.36 mgC·m - 2 ·d - 1 ) was only 1.57% of the POC flux. The total carbon flux mediated by diel migrants (respiration plus potential ingestion) ranged between 3.37 and 9.22% of the POC flux; which is three-fold higher than calculating ingestion fluxes from gut pigments. Our results suggest that the fluxes by diel migrants play a small role in the downward flux of carbon in the open ocean during the post-bloom period.

  15. Density limit in JT-60

    International Nuclear Information System (INIS)

    Kamada, Yutaka; Hosogane, Nobuyuki; Hirayama, Toshio; Tsunematsu, Toshihide

    1990-05-01

    This report studies mainly the density limit for a series of gas- and pellet-fuelled limiter discharges in JT-60. With the pellet injection into high-current/low-q (q(a)=2.3∼2.5) discharges, the Murakami factor reaches up to 10∼13 x 10 19 m -2 T -1 . The values are about factors of 1.5∼2.0 higher than those for usual gas-fuelled discharges. The pellet injected discharges have high central density, whereas the electron density in the outer region (a/2 abs and n e 2 (r=50 cm) x Z eff (r=50 cm). (author)

  16. Dosimetry of mixed gamma - neutron fluxes in the active zone of working reactor and gamma-flux after quenching

    International Nuclear Information System (INIS)

    Mussaeva, M.A.; Zinov'ev, V.; Ibragimova, E.M.; Muminov, M.I.

    2006-01-01

    vacancy, varied within 0.57 - 2.8. Besides, pure SiO 2 samples in the Cd - can filled with water were irradiated in the thermal column of operating reactor for 6 hours. Under these conditions the fast neutron flux was estimated as weak as 6·10 10 n/cm 2 s, the fluence was 1.3·10 15 cm -2 . The optical density of band 215 nm was 2.5, while the neutron fluence was ∼30 times less. Thus, the concentration of E ' -centers does not correlate with a neutron fluence. To extract the contribution from gamma-rays into the induced optical absorption in the glass matrix, samples of pure SiO 2 were irradiated by gamma-rays in 4 hours after quenching the reactor at the ionization current of 50 nA during 30 minutes, 12 and 24 hours; next time in 9 hours after the quenching at 40 nA and for 120 hours at 10 nA. In this case the gamma-spectrum did not include 10 MeV line from oxygen due to the short life-time, which prevails in the spectrum of working reactor. Maximal dose of γ-radiation of the quenched reactor was shown to induce the band at 215 nm up to the density of 0.5. When the sample was in contact with water the efficiency of E'-center production was 2 times higher that in dry condition. Thus, the high efficiency of structure defect production in SiO 2 glass owes to the influence of 10 MeV γ-radiation of the working reactor. The work was carried out under the grant F2.1.2 from Center of Science and Technology of Uzbekistan and supported by NATO CBP.EAP.CLG.981765. (author)

  17. The Fourier transform of tubular densities

    KAUST Repository

    Prior, C B

    2012-05-18

    We consider the Fourier transform of tubular volume densities, with arbitrary axial geometry and (possibly) twisted internal structure. This density can be used to represent, among others, magnetic flux or the electron density of biopolymer molecules. We consider tubes of both finite radii and unrestricted radius. When there is overlap of the tube structure the net density is calculated using the super-position principle. The Fourier transform of this density is composed of two expressions, one for which the radius of the tube is less than the curvature of the axis and one for which the radius is greater (which must have density overlap). This expression can accommodate an asymmetric density distribution and a tube structure which has non-uniform twisting. In addition we give several simpler expressions for isotropic densities, densities of finite radius, densities which decay at a rate sufficient to minimize local overlap and finally individual surfaces of the tube manifold. These simplified cases can often be expressed as arclength integrals and can be evaluated using a system of first-order ODEs. © 2012 IOP Publishing Ltd.

  18. The Fourier transform of tubular densities

    International Nuclear Information System (INIS)

    Prior, C B; Goriely, A

    2012-01-01

    We consider the Fourier transform of tubular volume densities, with arbitrary axial geometry and (possibly) twisted internal structure. This density can be used to represent, among others, magnetic flux or the electron density of biopolymer molecules. We consider tubes of both finite radii and unrestricted radius. When there is overlap of the tube structure the net density is calculated using the super-position principle. The Fourier transform of this density is composed of two expressions, one for which the radius of the tube is less than the curvature of the axis and one for which the radius is greater (which must have density overlap). This expression can accommodate an asymmetric density distribution and a tube structure which has non-uniform twisting. In addition we give several simpler expressions for isotropic densities, densities of finite radius, densities which decay at a rate sufficient to minimize local overlap and finally individual surfaces of the tube manifold. These simplified cases can often be expressed as arclength integrals and can be evaluated using a system of first-order ODEs. (paper)

  19. Physics of Magnetic Flux Ropes

    CERN Document Server

    Priest, E R; Lee, L C

    1990-01-01

    The American Geophysical Union Chapman Conference on the Physics of Magnetic Flux Ropes was held at the Hamilton Princess Hotel, Hamilton, Bermuda on March 27–31, 1989. Topics discussed ranged from solar flux ropes, such as photospheric flux tubes, coronal loops and prominences, to flux ropes in the solar wind, in planetary ionospheres, at the Earth's magnetopause, in the geomagnetic tail and deep in the Earth's magnetosphere. Papers presented at that conference form the nucleus of this book, but the book is more than just a proceedings of the conference. We have solicited articles from all interested in this topic. Thus, there is some material in the book not discussed at the conference. Even in the case of papers presented at the conference, there is generally a much more detailed and rigorous presentation than was possible in the time allowed by the oral and poster presentations.

  20. Notes on neutron flux measurement

    International Nuclear Information System (INIS)

    Alcala Ruiz, F.

    1984-01-01

    The main purpose of this work is to get an useful guide to carry out topical neutron flux measurements. Although the foil activation technique is used in the majority of the cases, other techniques, such as those based on fission chambers and self-powered neutron detectors, are also shown. Special interest is given to the description and application of corrections on the measurement of relative and absolute induced activities by several types of detectors (scintillators, G-M and gas proportional counters). The thermal arid epithermal neutron fluxes, as determined in this work, are conventional or effective (West cots fluxes), which are extensively used by the reactor experimentalists; however, we also give some expressions where they are related to the integrated neutron fluxes, which are used in neutron calculations. (Author) 16 refs

  1. Specification of ROP flux shape

    International Nuclear Information System (INIS)

    Min, Byung Joo; Gray, A.

    1997-06-01

    The CANDU 9 480/SEU core uses 0.9% SEU (Slightly Enriched Uranium) fuel. The use f SEU fuel enables the reactor to increase the radial power form factor from 0.865, which is typical in current natural uranium CANDU reactors, to 0.97 in the nominal CANDU 9 480/SEU core. The difference is a 12% increase in reactor power. An additional 5% increase can be achieved due to a reduced refuelling ripple. The channel power limits were also increased by 3% for a total reactor power increase of 20%. This report describes the calculation of neutron flux distributions in the CANDU 9 480/SEU core under conditions specified by the C and I engineers. The RFSP code was used to calculate of neutron flux shapes for ROP analysis. Detailed flux values at numerous potential detector sites were calculated for each flux shape. (author). 6 tabs., 70 figs., 4 refs

  2. Specification of ROP flux shape

    Energy Technology Data Exchange (ETDEWEB)

    Min, Byung Joo [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Gray, A [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)

    1997-06-01

    The CANDU 9 480/SEU core uses 0.9% SEU (Slightly Enriched Uranium) fuel. The use f SEU fuel enables the reactor to increase the radial power form factor from 0.865, which is typical in current natural uranium CANDU reactors, to 0.97 in the nominal CANDU 9 480/SEU core. The difference is a 12% increase in reactor power. An additional 5% increase can be achieved due to a reduced refuelling ripple. The channel power limits were also increased by 3% for a total reactor power increase of 20%. This report describes the calculation of neutron flux distributions in the CANDU 9 480/SEU core under conditions specified by the C and I engineers. The RFSP code was used to calculate of neutron flux shapes for ROP analysis. Detailed flux values at numerous potential detector sites were calculated for each flux shape. (author). 6 tabs., 70 figs., 4 refs.

  3. High Flux Isotope Reactor (HFIR)

    Data.gov (United States)

    Federal Laboratory Consortium — The HFIR at Oak Ridge National Laboratory is a light-water cooled and moderated reactor that is the United States’ highest flux reactor-based neutron source. HFIR...

  4. Flux networks in metabolic graphs

    International Nuclear Information System (INIS)

    Warren, P B; Queiros, S M Duarte; Jones, J L

    2009-01-01

    A metabolic model can be represented as a bipartite graph comprising linked reaction and metabolite nodes. Here it is shown how a network of conserved fluxes can be assigned to the edges of such a graph by combining the reaction fluxes with a conserved metabolite property such as molecular weight. A similar flux network can be constructed by combining the primal and dual solutions to the linear programming problem that typically arises in constraint-based modelling. Such constructions may help with the visualization of flux distributions in complex metabolic networks. The analysis also explains the strong correlation observed between metabolite shadow prices (the dual linear programming variables) and conserved metabolite properties. The methods were applied to recent metabolic models for Escherichia coli, Saccharomyces cerevisiae and Methanosarcina barkeri. Detailed results are reported for E. coli; similar results were found for other organisms

  5. Boundary fluxes for nonlocal diffusion

    Science.gov (United States)

    Cortazar, Carmen; Elgueta, Manuel; Rossi, Julio D.; Wolanski, Noemi

    We study a nonlocal diffusion operator in a bounded smooth domain prescribing the flux through the boundary. This problem may be seen as a generalization of the usual Neumann problem for the heat equation. First, we prove existence, uniqueness and a comparison principle. Next, we study the behavior of solutions for some prescribed boundary data including blowing up ones. Finally, we look at a nonlinear flux boundary condition.

  6. Energy flux of hot atoms

    International Nuclear Information System (INIS)

    Wotzak, G.P.; Kostin, M.D.

    1976-01-01

    The process in which hot atoms collide with thermal atoms of a gas, transfer kinetic energy to them, and produce additional hot atoms is investigated. A stochastic method is used to obtain numerical results for the spatial and time dependent energy flux of hot atoms in a gas. The results indicate that in hot atom systems a front followed by an intense energy flux of hot atoms may develop

  7. Integral emission factors for methane determined using urban flux measurements and local-scale inverse models

    Science.gov (United States)

    Christen, Andreas; Johnson, Mark; Molodovskaya, Marina; Ketler, Rick; Nesic, Zoran; Crawford, Ben; Giometto, Marco; van der Laan, Mike

    2013-04-01

    contributes to each measurement interval (30 min), which varies with wind direction and stability. A detailed geographic information system of the urban surface combined with traffic counts and building energy models makes it possible to statistically relate fluxes to vehicle density (km driven) and buildings (gas heated volume) - and ultimately quantify the contribution of space heating, transport sector and fugitive emissions to the total emitted CH4 from an urban environment. The measured fluxes of CH4 over the selected urban environment averaged to 22.8 mg CH4 m-2 day-1 during the study period. Compared with the simultaneously measured CO2 emissions, the contribution of CH4, however, accounts for only about 3% of the total LLGHG emissions from this particular urban surface. Traffic contributed 8.8 mg CH4 m-2 day-1, equivalent to 39% of the total CH4 flux. The determined emission factor for the typical fleet composition is 0.062 g CH4 per km driven which is higher than upscaled fleet emission factors (EPA) by a factor of two. This discrepancy can be partially explained through the slower city traffic with frequent idling (traffic congestion), fleet composition and cold starts. Emissions of CH4 by domestic space heating (55% of the total CH4 flux or 12.7 mg CH4 m-2 day-1) are also higher than estimated from upscaled emission factors. There is no evidence of substantial unknown sources such as soil processes, combustion of wood, and leakages from gas distribution pipes (residual: 6% or 1.3 mg CH4 m-2 day-1). The presented study is among the first direct measurements of CH4 emissions over an urban surface and demonstrates that flux measurements of greenhouse gases can be used to determine sources and emission factors in complex urban situations.

  8. Flux tubes at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Cea, Paolo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Dipartimento di Fisica dell’Università di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cosmai, Leonardo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cuteri, Francesca; Papa, Alessandro [Dipartimento di Fisica, Università della Calabria & INFN-Cosenza,Ponte Bucci, cubo 31C, I-87036 Rende (Cosenza) (Italy)

    2016-06-07

    The chromoelectric field generated by a static quark-antiquark pair, with its peculiar tube-like shape, can be nicely described, at zero temperature, within the dual superconductor scenario for the QCD confining vacuum. In this work we investigate, by lattice Monte Carlo simulations of the SU(3) pure gauge theory, the fate of chromoelectric flux tubes across the deconfinement transition. We find that, if the distance between the static sources is kept fixed at about 0.76 fm ≃1.6/√σ and the temperature is increased towards and above the deconfinement temperature T{sub c}, the amplitude of the field inside the flux tube gets smaller, while the shape of the flux tube does not vary appreciably across deconfinement. This scenario with flux-tube “evaporation” above T{sub c} has no correspondence in ordinary (type-II) superconductivity, where instead the transition to the phase with normal conductivity is characterized by a divergent fattening of flux tubes as the transition temperature is approached from below. We present also some evidence about the existence of flux-tube structures in the magnetic sector of the theory in the deconfined phase.

  9. P fluxes and exotic branes

    Energy Technology Data Exchange (ETDEWEB)

    Lombardo, Davide M. [Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy); Riccioni, Fabio [INFN - Sezione di Roma, Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy); Risoli, Stefano [Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy); INFN - Sezione di Roma, Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy)

    2016-12-21

    We consider the N=1 superpotential generated in type-II orientifold models by non-geometric fluxes. In particular, we focus on the family of P fluxes, that are related by T-duality transformations to the S-dual of the Q flux. We determine the general rule that transforms a given flux in this family under a single T-duality transformation. This rule allows to derive a complete expression for the superpotential for both the IIA and the IIB theory for the particular case of a T{sup 6}/[ℤ{sub 2}×ℤ{sub 2}] orientifold. We then consider how these fluxes modify the generalised Bianchi identities. In particular, we derive a fully consistent set of quadratic constraints coming from the NS-NS Bianchi identities. On the other hand, the P flux Bianchi identities induce tadpoles, and we determine a set of exotic branes that can be consistently included in order to cancel them. This is achieved by determining a universal transformation rule under T-duality satisfied by all the branes in string theory.

  10. P fluxes and exotic branes

    International Nuclear Information System (INIS)

    Lombardo, Davide M.; Riccioni, Fabio; Risoli, Stefano

    2016-01-01

    We consider the N=1 superpotential generated in type-II orientifold models by non-geometric fluxes. In particular, we focus on the family of P fluxes, that are related by T-duality transformations to the S-dual of the Q flux. We determine the general rule that transforms a given flux in this family under a single T-duality transformation. This rule allows to derive a complete expression for the superpotential for both the IIA and the IIB theory for the particular case of a T 6 /[ℤ 2 ×ℤ 2 ] orientifold. We then consider how these fluxes modify the generalised Bianchi identities. In particular, we derive a fully consistent set of quadratic constraints coming from the NS-NS Bianchi identities. On the other hand, the P flux Bianchi identities induce tadpoles, and we determine a set of exotic branes that can be consistently included in order to cancel them. This is achieved by determining a universal transformation rule under T-duality satisfied by all the branes in string theory.

  11. Controlling the flux dynamics in superconductors by nanostructured magnetic arrays

    Science.gov (United States)

    Kapra, Andrey

    In this thesis we investigate theoretically how the critical current jc of nano-engineered mesoscopic superconducting film can be improved and how one can control the dynamics of the magnetic flux, e.g., the transition from flux-pinned to flux-flow regime, using arrays of magnetic nanostructures. In particularly we investigate: (1) Vortex transport phenomena in superconductors with deposited ferromagnetic structures on top, and the influence of the sample geometry on the critical parameters and on the vortex configurations. Changing geometry of the magnetic bars and magnetization of the bars will affect the critical current jc of the superconducting film. Such nanostructured ferromagnets strongly alter the vortex structure in its neighborhood. The influence of geometry, position and magnetization of the ferromagnet (single bar or regular lattice of the bars) on the critical parameters of the superconductor is investigated. (2) Effect of flux confinement in narrow superconducting channels with zigzag-shaped banks: the flux motion is confined in the transverse (perpendicular) direction of a diamond-cell-shape channel. The matching effect for the magnetic flux is found in the system relevantless of boundary condition. We discuss the dynamics of vortices in the samples and vortex pattern formation in the channel. We show how the inclusion of higher-Tc superconductor into the sample can lead to enhanced properties of the system. By adding an external driving force, we study the vortex dynamics. The different dynamic regimes are discussed. They allowed an effective control of magnetic flux in superconductors.

  12. Operation of the ORNL High Particle Flux Helicon Plasma Source

    International Nuclear Information System (INIS)

    Goulding, Richard Howell; Biewer, Theodore M.; Caughman, John B.; Chen, Guangye; Owen, Larry W.; Sparks, Dennis O.

    2011-01-01

    A high power, high particle flux rf-based helicon plasma source has been constructed at ORNL and operated at power levels up to 30 kW. High-density hydrogen and helium plasmas have been produced. The source has been designed as the basis for a linear plasma materials interaction (PMI) test facility that will generate particle fluxes Gamma(p) > 10(23) M-3 s(-1), and utilize additional ion and electron cyclotron heating to produce high parallel (to the magnetic field) heat fluxes of similar to 10 MW/m(2). An rf-based source for PMI research is of interest because high plasma densities are generated with no internal electrodes, allowing true steady state operation with minimal impurity generation. The ORNL helicon source has a diameter of 15 cm and to-date has operated at a frequency f = 13.56 MHz, with magnetic field strength vertical bar B vertical bar in the antenna region up to similar to 0.15 T. Maximum densities of 3 x 10(19) M-3 in He and 2.5 x 10(19) m(-3) in H have been achieved. Radial density profiles have been seen to be dependent on the axial vertical bar B vertical bar profile.

  13. Operation of the ORNL High Particle Flux Helicon Plasma Source

    International Nuclear Information System (INIS)

    Goulding, R. H.; Biewer, T. M.; Caughman, J. B. O.; Chen, G. C.; Owen, L. W.; Sparks, D. O.

    2011-01-01

    A high power, high particle flux rf-based helicon plasma source has been constructed at ORNL and operated at power levels up to 30 kW. High-density hydrogen and helium plasmas have been produced. The source has been designed as the basis for a linear plasma materials interaction (PMI) test facility that will generate particle fluxes Γ p 10 23 m -3 s -1 , and utilize additional ion and electron cyclotron heating to produce high parallel (to the magnetic field) heat fluxes of ∼10 MW/m 2 . An rf-based source for PMI research is of interest because high plasma densities are generated with no internal electrodes, allowing true steady state operation with minimal impurity generation. The ORNL helicon source has a diameter of 15 cm and to-date has operated at a frequency f = 13.56 MHz, with magnetic field strength |B| in the antenna region up to ∼0.15 T. Maximum densities of 3x10 19 m -3 in He and 2.5x10 19 m -3 in H have been achieved. Radial density profiles have been seen to be dependent on the axial |B| profile.

  14. LANSCE steady state unperturbed thermal neutron fluxes at 100 μA

    International Nuclear Information System (INIS)

    Russell, G.J.

    1989-01-01

    The ''maximum'' unperturbed, steady state thermal neutron flux for LANSCE is calculated to be 2 /times/ 10 13 n/cm 2 -s for 100 μA of 800-MeV protons. This LANSCE neutron flux is a comparable entity to a steady state reactor thermal neutron flux. LANSCE perturbed steady state thermal neutron fluxes have also been calculated. Because LANSCE is a pulsed neutron source, much higher ''peak'' (in time) neutron fluxes can be generated than at a steady state reactor source. 5 refs., 5 figs

  15. Study of heat flux deposition in the Tore Supra Tokamak

    International Nuclear Information System (INIS)

    Carpentier, S.

    2009-02-01

    Accurate measurements of heat loads on internal tokamak components is essential for protection of the device during steady state operation. The optimisation of experimental scenarios also requires an in depth understanding of the physical mechanisms governing the heat flux deposition on the walls. The objective of this study is a detailed characterisation of the heat flux to plasma facing components (PFC) of the Tore Supra tokamak. The power deposited onto Tore Supra PFCs is calculated using an inverse method, which is applied to both the temperature maps measured by infrared thermography and to the enthalpy signals from calorimetry. The derived experimental heat flux maps calculated on the toroidal pumped limiter (TPL) are then compared with theoretical heat flux density distributions from a standard SOL-model. They are two experimental observations that are not consistent with the model: significant heat flux outside the theoretical wetted area, and heat load peaking close to the tangency point between the TPL and the last closed field surface (LCFS). An experimental analysis for several discharges with variable security factors q is made. In the area consistent with the theoretical predictions, this parametric study shows a clear dependence between the heat flux length λ q (estimated in the SOL (scrape-off layer) from the IR measurements) and the magnetic configuration. We observe that the spreading of heat fluxes on the component is compensated by a reduction of the power decay length λ q in the SOL when q decreases. On the other hand, in the area where the derived experimental heat loads are not consistent with the theoretical predictions, we observe that the spreading of heat fluxes outside the theoretical boundary increases when q decreases, and is thus not counterbalanced. (author)

  16. The isotope density inverse problem in multigroup neutron transport

    International Nuclear Information System (INIS)

    Zazula, J.M.

    1981-01-01

    The inverse problem for stationary multigroup anisotropic neutron transport is discussed in order to search for isotope densities in multielement medium. The spatial- and angular-integrated form of neutron transport equation, in terms of the flux in a group - density of an element spatial correlation, leads to a set of integral functionals for the densities weighted by the group fluxes. Some methods of approximation to make the problem uniquently solvable are proposed. Particularly P 0 angular flux information and the spherically-symetrical geometry of an infinite medium are considered. The numerical calculation using this method related to sooner evaluated direct problem data gives promising agreement with primary densities. This approach would be the basis for further application in an elemental analysis of a medium, using an isotopic neutron source and a moving, energy-dependent neutron detector. (author)

  17. A FLUX SCALE FOR SOUTHERN HEMISPHERE 21 cm EPOCH OF REIONIZATION EXPERIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Daniel C.; Bowman, Judd [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States); Parsons, Aaron R.; Ali, Zaki; Pober, Jonathan C. [Astronomy Department, University of California, Berkeley, CA (United States); Aguirre, James E.; Moore, David F. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA (United States); Bradley, Richard F. [Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA (United States); Carilli, Chris L. [National Radio Astronomy Observatory, Socorro, NM (United States); DeBoer, David R.; Dexter, Matthew R.; MacMahon, Dave H. E. [Radio Astronomy Lab., University of California, Berkeley, CA (United States); Gugliucci, Nicole E.; Klima, Pat [National Radio Astronomy Observatory, Charlottesville, VA (United States); Manley, Jason R.; Walbrugh, William P. [Square Kilometer Array, South Africa Project, Cape Town (South Africa); Stefan, Irina I. [Cavendish Laboratory, Cambridge (United Kingdom)

    2013-10-20

    We present a catalog of spectral measurements covering a 100-200 MHz band for 32 sources, derived from observations with a 64 antenna deployment of the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) in South Africa. For transit telescopes such as PAPER, calibration of the primary beam is a difficult endeavor and errors in this calibration are a major source of error in the determination of source spectra. In order to decrease our reliance on an accurate beam calibration, we focus on calibrating sources in a narrow declination range from –46° to –40°. Since sources at similar declinations follow nearly identical paths through the primary beam, this restriction greatly reduces errors associated with beam calibration, yielding a dramatic improvement in the accuracy of derived source spectra. Extrapolating from higher frequency catalogs, we derive the flux scale using a Monte Carlo fit across multiple sources that includes uncertainty from both catalog and measurement errors. Fitting spectral models to catalog data and these new PAPER measurements, we derive new flux models for Pictor A and 31 other sources at nearby declinations; 90% are found to confirm and refine a power-law model for flux density. Of particular importance is the new Pictor A flux model, which is accurate to 1.4% and shows that between 100 MHz and 2 GHz, in contrast with previous models, the spectrum of Pictor A is consistent with a single power law given by a flux at 150 MHz of 382 ± 5.4 Jy and a spectral index of –0.76 ± 0.01. This accuracy represents an order of magnitude improvement over previous measurements in this band and is limited by the uncertainty in the catalog measurements used to estimate the absolute flux scale. The simplicity and improved accuracy of Pictor A's spectrum make it an excellent calibrator in a band important for experiments seeking to measure 21 cm emission from the epoch of reionization.

  18. Changes to the Carbon and Energy fluxes in a Northern Peatland with Thawing Permafrost

    Science.gov (United States)

    Harder, S. R.; Roulet, N. T.; Crill, P. M.; Strachan, I. B.

    2017-12-01

    The maintenance of thaw of high carbon density landscapes in the permafrost region ultimately depends of how the energy balance is partitioned as temperatures and precipitation change, yet there are comparatively few energy balance studies, especially in peatlands that contain permafrost. While permafrost peatlands are currently net sinks of carbon, as Arctic temperatures rise and permafrost thaws, the future of these ecosystems and their capacity for carbon uptake is in question. Since 2012 we have been measuring the spatially integrated CO2, energy and water vapour fluxes from the Stordalen peatland (68°22'N, 19°03'E) using eddy covariance (EC). The Stordalen peatland is a heterogeneous peatland in the discontinuous permafrost zone where permafrost thaw is actively occurring, resulting in large changes to the landscape from year to year. Areas where permafrost is present are elevated by up to 1.5 m compared to the areas where permafrost has thawed causing differences in water table depth, peat temperatures, snow distribution, vegetation community and therefore in the carbon and energy fluxes. Our EC tower is located on the edge of a permafrost peat plateau (or palsa) where one fetch measures fluxes from an area underlain by permafrost and the other fetch sees the portion of the peatland where the permafrost has thawed. Within each sector, we have an array of soil temperature and water content sensors to determine the physical characteristics of each fetch. Extensive vegetation surveys (based on plant functional types or PFTs) have also been conducted to run a footprint analysis on the flux data to complete a comparative analysis of the magnitude and variability of the carbon and energy exchanges from PFT. The footprint analysis allows us to explain the difference in energy and carbon fluxes by examining the ecological, biogeochemical and physical characteristics within each footprint. We see distinctly different energy partitioning between the fetches

  19. Non-equilibrium reactive flux: A unified framework for slow and fast reaction kinetics.

    Science.gov (United States)

    Bose, Amartya; Makri, Nancy

    2017-10-21

    The flux formulation of reaction rate theory is recast in terms of the expectation value of the reactive flux with an initial condition that corresponds to a non-equilibrium, factorized reactant density. In the common case of slow reactive processes, the non-equilibrium expression reaches the plateau regime only slightly slower than the equilibrium flux form. When the reactants are described by a single quantum state, as in the case of electron transfer reactions, the factorized reactant density describes the true initial condition of the reactive process. In such cases, the time integral of the non-equilibrium flux expression yields the reactant population as a function of time, allowing characterization of the dynamics in cases where there is no clear separation of time scales and thus a plateau regime cannot be identified. The non-equilibrium flux offers a unified approach to the kinetics of slow and fast chemical reactions and is ideally suited to mixed quantum-classical methods.

  20. Inundation and Gas Fluxes from Amazon Lakes and Wetlands

    Science.gov (United States)

    Melack, J. M.; MacIntyre, S.; Forsberg, B. R.; Amaral, J. H.; Barbosa, P.

    2015-12-01

    Inundation areas and wetland habitats for the lowland Amazon basin derived remote sensing with synthetic aperture radar are combined with measurements of greenhouse gas evasion derived from field measurements and new formulations of atmosphere-water. On-going field studies in representative aquatic habitats on the central Amazon floodplain are combining monthly measurements of carbon dioxide and methane concentrations and fluxes to the atmosphere with deployment of meteorological sensors and high-resolution thermistors and optical dissolved oxygen sensors. A real-time cavity ringdown spectrometer is being used to determine the gas concentrations; vertical profiles were obtained by using an equilibrator to extract gases from water, and floating chambers are used to assess fluxes. Gas fluxes varied as a function of season, habitat and water depth. Greatest carbon dioxide fluxes occurred during high and falling water levels. During low water, periods with high chlorophyll, indicative of phytoplankton, the flux of carbon dioxide switched from being emitted from the lake to being taken-up by the lake some of the time. The highest pCO2 concentration (5500 μatm) was about three times higher than the median (1700 μatm). Higher CO2 fluxes were observed in open water than in areas with flooded or floating vegetation. In contrast, methane fluxes were higher in vegetated regions. We measured turbulence as rate of dissipation of turbulent kinetic energy based on microstructure profiling. Comparison of these measurements with those calculated from meteorological and time series measurements validated new equations for turbulent kinetic energy dissipation (TKE) rates during moderate winds and cooling and illustrated that the highest dissipation rates occurred under heating. Measured gas exchange coefficients (k600) were similar to those based on the TKE dissipation rates and are well described using the surface renewal model. These k values are several times higher than

  1. On the origin of plasma density blobs

    Energy Technology Data Exchange (ETDEWEB)

    Krasheninnikov, S.I., E-mail: skrash@mae.ucsd.edu

    2016-12-01

    By keeping nonlinear Boltzmann factor in electron density dependence on electrostatic potential it is demonstrated that large plasma density blobs, often seen in experiment inside separatrix, can exist within the framework of drift wave dynamics. The estimates show that plasma density in a blob can be ∼3 times higher that average plasma density, but hardly exceeds this limit, which in a ball park is in agreement with experimental observations.

  2. Measuring oxidation processes: Atomic oxygen flux monitor

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Of the existing 95 high-energy accelerators in the world, the Stanford Linear Collider (SLC) at the Stanford Linear Accelerator Center (SLAC) is the only one of the linear-collider type, where electrons and positrons are smashed together at energies of 50 GeV using linear beams instead of beam rings for achieving interactions. Use of a collider eliminates energy losses in the form of x-rays due to the curved trajectory of the rings, a phenomena known as bremsstrauhlung. Because these losses are eliminated, higher interaction energies are reached. Consequently the SLC produced the first Z particle in quantities large enough to allow measurement of its physical properties with some accuracy. SLAC intends to probe still deeper into the structure of matter by next polarizing the electrons in the beam. The surface of the source for these polarized particles, typically gallium arsenide, must be kept clean of contaminants. One method for accomplishing this task requires the oxidation of the surface, from which the oxidized contaminants are later boiled off. The technique requires careful measurement of the oxidation process. SLAC researchers have developed a technique for measuring the atomic oxygen flux in this process. The method uses a silver film on a quartz-crystal, deposition-rate monitor. Measuring the initial oxidation rate of the silver, which is proportional to the atomic oxygen flux, determines a lower limit on that flux in the range of 10 13 to 10 17 atoms per square centimeter per second. Furthermore, the deposition is reversible by exposing the sensor to atomic hydrogen. This technique has wider applications to processes in solid-state and surface physics as well as surface chemistry. In semiconductor manufacturing where a precise thickness of oxide must be deposited, this technique could be used to monitor the critical flux of atomic oxygen in the process

  3. Edge plasma density convection during ICRH on Tore Supra

    International Nuclear Information System (INIS)

    Becoulet, M.; Colas, L.; Gunn, J.; Ghendrih, Ph.; Becoulet, A.; Pecoul, S.; Heuraux, S.

    2001-11-01

    The 2D edge plasma density distribution around ion cyclotron resonance heating (ICRH) antennae is studied experimentally and numerically in the tokamak Tore Supra (TS). A local density decrease in front of the loaded ICRH antenna ('pump-out' effect) is demonstrated by Langmuir probe measurements in a low recycling regime. An up-down asymmetry in the heat-flux and in the antenna erosion is also observed, and is associated with poloidal variations of the local density. These density redistributions are ascribed to an ExB convection process linked with RF-sheaths. To assess this interpretation, the 2D transport code CELLS was developed for modeling the density distribution near an antenna. The code takes into account perpendicular diffusion, parallel transport and convection in RF-sheath-driven potentials given by the 3D-antenna code ICANT. The strong density differences obtained in simulations reproduce up-down asymmetries of the heat fluxes. (authors)

  4. Edge plasma density convection during ICRH on Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Becoulet, M.; Colas, L.; Gunn, J.; Ghendrih, Ph.; Becoulet, A. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Pecoul, S.; Heuraux, S. [Nancy-1 Univ., 54 (France). Lab. de Physique des Milieux Ionises

    2001-11-01

    The 2D edge plasma density distribution around ion cyclotron resonance heating (ICRH) antennae is studied experimentally and numerically in the tokamak Tore Supra (TS). A local density decrease in front of the loaded ICRH antenna ('pump-out' effect) is demonstrated by Langmuir probe measurements in a low recycling regime. An up-down asymmetry in the heat-flux and in the antenna erosion is also observed, and is associated with poloidal variations of the local density. These density redistributions are ascribed to an ExB convection process linked with RF-sheaths. To assess this interpretation, the 2D transport code CELLS was developed for modeling the density distribution near an antenna. The code takes into account perpendicular diffusion, parallel transport and convection in RF-sheath-driven potentials given by the 3D-antenna code ICANT. The strong density differences obtained in simulations reproduce up-down asymmetries of the heat fluxes. (authors)

  5. Particle fluxes in atomic collision cascades

    International Nuclear Information System (INIS)

    Sckerl, B.W.; Sigmund, P.; Vicanek, M.

    1996-01-01

    The flux of recoil atoms in atomic collision cascades induced by an ion beam or another source of energetic particles in a material is known to approach isotropy at kinetic energies far below the beam energy. A variety of irradiation effects can be explained satisfactorily on the basis of an isotropic particle flux, but significant deviations from this simple behavior are known to exist. While numerous examples have been studied by numerical simulation of cascade processes, the systematics is, by and large, unknown. The present study aims at general scaling properties and estimates of the magnitude of moderate deviations from isotropy and their spatial dependence for a wide range of beam and material parameters. Anisotropies introduced by crystal structure are ignored. Although it is well established that cascade anisotropy is related to the momentum of beam particles, previous attempts to quantify this relation have failed. We have found that there are two leading correction terms to the isotropic particle flux, a well-known term centered around the beam direction as a symmetry axis and a new term proportional to the gradient of the deposited-energy density. As a general rule the two contributions are either both significant or both negligible. Specific situations in which the gradient term dominates are, however, of considerable interest in applications. The parameters which characterize the anisotropy of collision cascades also determine the deposition of momentum, but the connection is less straightforward than asserted hitherto. General principles are first illustrated on the specific case of elastic-collision cascades under self-bombardment which contains the essentials. Thereafter several generalizations are made, including atomic binding forces and inelasticity as well as allowance for multicomponent materials. Application areas in mixing and sputtering are outlined. (au) 58 refs

  6. Long-term temporal variability of the radon-222 exhalation flux from a landform covered by low uranium grade waste rock

    International Nuclear Information System (INIS)

    Bollhöfer, Andreas; Doering, Che

    2016-01-01

    Radon-222 exhalation flux densities from two different substrates of several metres thickness, waste rock and waste rock mixed with approximately 30% lateritic material, were measured over a period of five years in the wet-dry tropics of Northern Australia. Fourteen measurement campaigns using activated charcoal canisters (n > 1000) covered both dry and wet seasons and showed differences in seasonal and long term trends of the "2"2"2Rn exhalation flux densities normalised to the "2"2"6Ra activity concentrations of the substrate. Dry season "2"2"2Rn exhalation was generally higher for the mixed substrate, due to the larger fraction of fines. Seasonality established within the first year of landform construction on the mixed substrate, due to the higher water holding capacity of the lateritic material. In contrast, waste rock only shows no seasonality until years four and five after construction, when average normalised dry season "2"2"2Rn exhalation flux densities from waste rock increase to values (0.47 ± 0.06 mBq m"−"2 s"−"1 per Bq kg"−"1) similar to the mixed substrate (0.64 ± 0.08 mBq m"−"2 s"−"1 per Bq kg"−"1), likely due to an increase in fines from rapid weathering of the schistose waste rock. Volumetric water content has been used to parametrize relative "2"2"2Rn exhalation and we determined that wet season "2"2"2Rn exhalation is about 40% of the dry season exhalation. - Highlights: • We determined "2"2"2Rn exhalation flux densities normalised to "2"2"6Ra activity concentrations (R_E_-_R) for two substrates. • R_E_-_R was lower for waste rock only compared to waste rock blended with 30% fine grained lateritic material. • Seasonality in waste rock "2"2"2Rn exhalation flux densities established 4 years after construction. • Wet season R_E_-_R was about 40% of the dry season R_E_-_R.

  7. Analyzer of neutron flux in real time

    International Nuclear Information System (INIS)

    Rojas S, A.S.; Carrillo M, R.A.; Balderas, E.G.

    1999-01-01

    With base in the study of the real signals of neutron flux of instability events occurred in the Laguna Verde nuclear power plant where the nucleus oscillation phenomena of the reactor are in the 0 to 2.5 Hz range, it has been seen the possibility about the development a surveillance and diagnostic equipment capable to analyze in real time the behavior of nucleus in this frequencies range. An important method for surveillance the stability of the reactor nucleus is the use of the Power spectral density which allows to determine the frequencies and amplitudes contained in the signals. It is used an instrument carried out by LabVIEW graphic programming with a data acquisition card of 16 channels which works at Windows 95/98 environment. (Author)

  8. Skeleton tables of burnout heat flux

    International Nuclear Information System (INIS)

    Kirillov, P.L.; Bobkov, V.P.; Boltenko, Eh.A.; Vinogradov, V.N.; Katan, I.B.; Smogalev, I.P.

    1991-01-01

    New methods of generating and arranging new reference data on critical thermal flux density during steam and water mixture flow in vertical round fubes are discussed. The modern requirements to such data include the assessment of data reliability and error, internal agreement, validation by physical and mathematical models, verification using a large amount of experimental results. The available reference data feature a number of drawbacks: they are not accurate enough and are limited by the parameters; other data feature a significant spread in values at the neighbouring values of parameters, discrepancy with the experimental results, not always substantiated extrapolations. A new version of skeleton tables, which are free from a major part of above disadvantages, is proposed

  9. EU Development of High Heat Flux Components

    International Nuclear Information System (INIS)

    Linke, J.; Lorenzetto, P.; Majerus, P.; Merola, M.; Pitzer, D.; Roedig, M.

    2005-01-01

    The development of plasma facing components for next step fusion devices in Europe is strongly focused to ITER. Here a wide spectrum of different design options for the divertor target and the first wall have been investigated with tungsten, CFC, and beryllium armor. Electron beam simulation experiments have been used to determine the performance of high heat flux components under ITER specific thermal loads. Beside thermal fatigue loads with power density levels up to 20 MWm -2 , off-normal events are a serious concern for the lifetime of plasma facing components. These phenomena are expected to occur on a time scale of a few milliseconds (plasma disruptions) or several hundred milliseconds (vertical displacement events) and have been identified as a major source for the production of neutron activated metallic or tritium enriched carbon dust which is of serious importance from a safety point of view.The irradiation induced material degradation is another critical concern for future D-T-burning fusion devices. In ITER the integrated neutron fluence to the first wall and the divertor armour will remain in the order of 1 dpa and 0.7 dpa, respectively. This value is low compared to future commercial fusion reactors; nevertheless, a nonnegligible degradation of the materials has been detected, both for mechanical and thermal properties, in particular for the thermal conductivity of carbon based materials. Beside the degradation of individual material properties, the high heat flux performance of actively cooled plasma facing components has been investigated under ITER specific thermal and neutron loads

  10. Study on coal char ignition by radiant heat flux.

    Science.gov (United States)

    Korotkikh, A. G.; Slyusarskiy, K. V.

    2017-11-01

    The study on coal char ignition by CO2-continuous laser was carried out. The coal char samples of T-grade bituminous coal and 2B-grade lignite were studied via CO2-laser ignition setup. Ignition delay times were determined at ambient condition in heat flux density range 90-200 W/cm2. The average ignition delay time value for lignite samples were 2 times lower while this difference is larger in high heat flux region and lower in low heat flux region. The kinetic constants for overall oxidation reaction were determined using analytic solution of simplified one-dimensional heat transfer equation with radiant heat transfer boundary condition. The activation energy for lignite char was found to be less than it is for bituminous coal char by approximately 20 %.

  11. Overview: Cross-habitat flux of nutrients and detritus

    Science.gov (United States)

    Vanni, M.J.; DeAngelis, D.L.; Schindler, D.E.; Huxel, G.R.; Polis, G.A.; Power, M.E.; Huxel, G.R.

    2004-01-01

    Ecologists have long known that all ecosystems receive considerable quantities of materials from outside their boundaries (e.g., Elton 1927), and quantifying the magnitude of such fluxes has long been a central tenet of ecosystem ecology (e.g., Odum 1971). Thus, one might think that the consequences of such fluxes for food webs would be well understood. However, food webs have traditionally been viewed as if they were isolated from surrounding habitats, a habit that has been particularly persistent in the modeling of food webs. When fluxes from the outside have been considered, they have largely been restricted to constant inputs directly affecting the base of the food web (e.g., solar energy or nutrients), and usually only such issues as their effects on equilibrium conditions have been considered (e.g., the well-known relationships between nutrient inputs and average densities of various food web members).

  12. Particle flux at the outlet of an Ecr plasma source

    International Nuclear Information System (INIS)

    Gutierrez T, C.; Gonzalez D, J.

    1999-01-01

    The necessity of processing big material areas this has resulted in the development of plasma sources with the important property to be uniform in these areas. Also the continuous diminution in the size of substrates to be processed have stimulated the study of models which allow to predict the control of energy and the density of the ions and neutral particles toward the substrate. On the other hand, there are other applications of the plasma sources where it is very necessary to understand the effects generated by the energetic fluxes of ions and neutrals. These fluxes as well as another beneficial effects can improve the activation energy for the formation and improvement of the diffusion processes in the different materials. In this work, using the drift kinetic approximation is described a model to calculate the azimuthal and radial fluxes in the zone of materials processing of an Ecr plasma source type. The results obtained are compared with experimental results. (Author)

  13. Using thermalizers in measuring 'Ukryttia' object's FCM neutron fluxes

    CERN Document Server

    Krasnyanskaya, O G; Odinokin, G I; Pavlovich, V N

    2003-01-01

    The results of research of a thermalizer (heater) width influence on neutron thermalization efficiency during FCM neutron flux measuring in the 'Ukryttia' are described. The calculations of neutron flux densities were performed by the Monte-Carlo method with the help of computer code MCNP-4C for FCM different models.Three possible installations of detectors were considered: on FCM surface,inside the FCM, and inside the concrete under the FCM layer. It was shown,that in order to increase the sensitivity of neutron detectors in intermediate and fast neutrons field,and consequently, to decrease the dependence of the readings of spectral distribution of neutron flux,it is necessary to position the detector inside the so-called thermalizer or heater. The most reasonable application of thick 'heaters' is the situation, when the detector is placed on FCM surface.

  14. Flux surface shape and current profile optimization in tokamaks

    International Nuclear Information System (INIS)

    Dobrott, D.R.; Miller, R.L.

    1977-01-01

    Axisymmetric tokamak equilibria of noncircular cross section are analyzed numerically to study the effects of flux surface shape and current profile on ideal and resistive interchange stability. Various current profiles are examined for circles, ellipses, dees, and doublets. A numerical code separately analyzes stability in the neighborhood of the magnetic axis and in the remainder of the plasma using the criteria of Mercier and Glasser, Greene, and Johnson. Results are interpreted in terms of flux surface averaged quantities such as magnetic well, shear, and the spatial variation in the magnetic field energy density over the cross section. The maximum stable β is found to vary significantly with shape and current profile. For current profiles varying linearly with poloidal flux, the highest β's found were for doublets. Finally, an algorithm is presented which optimizes the current profile for circles and dees by making the plasma everywhere marginally stable

  15. Flux and Hall states in ABJM with dynamical flavors

    Energy Technology Data Exchange (ETDEWEB)

    Bea, Yago [Departamento de Física de Partículas and Instituto Galego de Física de Altas Enerxías,Universidade de Santiago de Compostela,E-15782 Santiago de Compostela (Spain); Jokela, Niko [Department of Physics and Helsinki Institute of Physics, University of Helsinki,P.O. Box 64, FIN-00014 (Finland); Lippert, Matthew [Institute for Theoretical Physics, University of Amsterdam,1098XH Amsterdam (Netherlands); Ramallo, Alfonso V. [Departamento de Física de Partículas and Instituto Galego de Física de Altas Enerxías,Universidade de Santiago de Compostela,E-15782 Santiago de Compostela (Spain); Zoakos, Dimitrios [Centro de Física do Porto and Departamento de Física e Astronomia,Faculdade de Ciências da Universidade do Porto,Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

    2015-03-02

    We study the physics of probe D6-branes with quantized internal worldvolume flux in the ABJM background with unquenched massless flavors. This flux breaks parity in the (2+1)-dimensional gauge theory and allows quantum Hall states. Parity breaking is also explicitly demonstrated via the helicity dependence of the meson spectrum. We obtain general expressions for the conductivities, both in the gapped Minkowski embeddings and in the compressible black hole ones. These conductivities depend on the flux and contain a contribution from the dynamical flavors which can be regarded as an effect of intrinsic disorder due to quantum fluctuations of the fundamentals. We present an explicit, analytic family of supersymmetric solutions with nonzero charge density, electric, and magnetic fields.

  16. Flux and Hall states in ABJM with dynamical flavors

    Science.gov (United States)

    Bea, Yago; Jokela, Niko; Lippert, Matthew; Ramallo, Alfonso V.; Zoakos, Dimitrios

    2015-03-01

    We study the physics of probe D6-branes with quantized internal worldvolume flux in the ABJM background with unquenched massless flavors. This flux breaks parity in the (2+1)-dimensional gauge theory and allows quantum Hall states. Parity breaking is also explicitly demonstrated via the helicity dependence of the meson spectrum. We obtain general expressions for the conductivities, both in the gapped Minkowski embeddings and in the compressible black hole ones. These conductivities depend on the flux and contain a contribution from the dynamical flavors which can be regarded as an effect of intrinsic disorder due to quantum fluctuations of the fundamentals. We present an explicit, analytic family of supersymmetric solutions with nonzero charge density, electric, and magnetic fields.

  17. Salp contributions to vertical carbon flux in the Sargasso Sea

    Science.gov (United States)

    Stone, Joshua P.; Steinberg, Deborah K.

    2016-07-01

    We developed a one-dimensional model to estimate salp contributions to vertical carbon flux at the Bermuda Atlantic Time-series Study (BATS) site in the North Atlantic subtropical gyre for a 17-yr period (April 1994 to December 2011). We based the model parameters on published rates of salp physiology and experimentally determined sinking and decomposition rates of salp carcasses. Salp grazing was low during non-bloom conditions, but routinely exceeded 100% of chlorophyll standing stock and primary production during blooms. Fecal pellet production was the largest source of salp carbon flux (78% of total), followed by respiration below 200 m (19%), sinking of carcasses (3%), and DOC excretion below 200 m (salp-mediated carbon flux. Seasonally, salp flux was higher during spring-summer than fall-winter, due to seasonal changes in species composition and abundance. Salp carbon export to 200 m was on average 2.3 mg C m-2 d-1 across the entire time series. This is equivalent to 11% of the mean 200 m POC flux measured by sediment traps in the region. During years with significant salp blooms, however, annually-averaged salp carbon export was the equivalent of up to 60% of trap POC flux at 200 m. Salp carbon flux attenuated slowly, and at 3200 m the average modeled carbon from salps was 109% of the POC flux measured in sediment traps at that depth. Migratory and carcass carbon export pathways should also be considered (alongside fecal pellet flux) as facilitating carbon export to sequestration depths in future studies.

  18. Materials compatibility and aging for flux and cleaner combinations

    Energy Technology Data Exchange (ETDEWEB)

    Archuleta, Kim M. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Piatt, Rochelle [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    A materials study of high reliability electronics cleaning is presented here. In Phase 1, mixed type substrates underwent a condensed contaminants application to view a worst- case scenario for unremoved flux with cleaning agent residue for parts in a silicone oil filled environment. In Phase 2, fluxes applied to copper coupons and to printed wiring boards underwent gentle cleaning then accelerated aging in air at 65% humidity and 30 O C. Both sets were aged for 4 weeks. Contaminants were no-clean (ORL0), water soluble (ORH1 liquid and ORH0 paste), and rosin (RMA; ROL0) fluxes. Defluxing agents were water, solvents, and engineered aqueous defluxers. In the first phase, coupons had flux applied and heated, then were placed in vials of oil with a small amount of cleaning agent and additional coupons. In the second phase, pairs of copper coupons and PWB were hand soldered by application of each flux, using tin-lead solder in a strip across the coupon or a set of test components on the PWB. One of each pair was cleaned in each cleaning agent, the first with a typical clean, and the second with a brief clean. Ionic contamination residue was measured before accelerated aging. After aging, substrates were removed and a visual record of coupon damage made, from which a subjective rank was applied for comparison between the various flux and defluxer combinations; more corrosion equated to higher rank. The ORH1 water soluble flux resulted in the highest ranking in both phases, the RMA flux the least. For the first phase, in which flux and defluxer remained on coupons, the aqueous defluxers led to worse corrosion. The vapor phase cleaning agents resulted in the highest ranking in the second phase, in which there was no physical cleaning. Further study of cleaning and rinsing parameters will be required.

  19. Water Use Patterns of Four Tropical Bamboo Species Assessed with Sap Flux Measurements.

    Science.gov (United States)

    Mei, Tingting; Fang, Dongming; Röll, Alexander; Niu, Furong; Hendrayanto; Hölscher, Dirk

    2015-01-01

    Bamboos are grasses (Poaceae) that are widespread in tropical and subtropical regions. We aimed at exploring water use patterns of four tropical bamboo species (Bambusa vulgaris, Dendrocalamus asper, Gigantochloa atroviolacea, and G. apus) with sap flux measurement techniques. Our approach included three experimental steps: (1) a pot experiment with a comparison of thermal dissipation probes (TDPs), the stem heat balance (SHB) method and gravimetric readings using potted B. vulgaris culms, (2) an in situ calibration of TDPs with the SHB method for the four bamboo species, and (3) field monitoring of sap flux of the four bamboo species along with three tropical tree species (Gmelina arborea, Shorea leprosula, and Hevea brasiliensis) during a dry and a wet period. In the pot experiment, it was confirmed that the SHB method is well suited for bamboos but that TDPs need to be calibrated. In situ, species-specific parameters for such calibration formulas were derived. During field monitoring we found that some bamboo species reached high maximum sap flux densities. Across bamboo species, maximal sap flux density increased with decreasing culm diameter. In the diurnal course, sap flux densities in bamboos peaked much earlier than radiation and vapor pressure deficit (VPD), and also much earlier than sap flux densities in trees. There was a pronounced hysteresis between sap flux density and VPD in bamboos, which was less pronounced in trees. Three of the four bamboo species showed reduced sap flux densities at high VPD values during the dry period, which was associated with a decrease in soil moisture content. Possible roles of internal water storage, root pressure and stomatal sensitivity are discussed.

  20. Flux flow and flux dynamics in high-Tc superconductors

    International Nuclear Information System (INIS)

    Bennett, L.H.; Turchinskaya, M.; Swartzendruber, L.J.; Roitburd, A.; Lundy, D.; Ritter, J.; Kaiser, D.L.

    1991-01-01

    Because high temperature superconductors, including BYCO and BSSCO, are type 2 superconductors with relatively low H(sub c 1) values and high H(sub c 2) values, they will be in a critical state for many of their applications. In the critical state, with the applied field between H(sub c 1) and H(sub c 2), flux lines have penetrated the material and can form a flux lattice and can be pinned by structural defects, chemical inhomogeneities, and impurities. A detailed knowledge of how flux penetrates the material and its behavior under the influence of applied fields and current flow, and the effect of material processing on these properties, is required in order to apply, and to improve the properties of these superconductors. When the applied field is changed rapidly, the time dependence of flux change can be divided into three regions, an initial region which occurs very rapidly, a second region in which the magnetization has a 1n(t) behavior, and a saturation region at very long times. A critical field is defined for depinning, H(sub c,p) as that field at which the hysteresis loop changes from irreversible to reversible. As a function of temperature, it is found that H(sub c,p) is well described by a power law with an exponent between 1.5 and 2.5. The behavior of H(sub c,p) for various materials and its relationship to flux flow and flux dynamics are discussed