PREFACE: XXX International Conference on Interaction of Intense Energy Fluxes with Matter

Science.gov (United States)

Fortov, V. E.; Khishchenko, K. V.; Karamurzov, B. S.; Efremov, V. P.; Sultanov, V. G.

2015-11-01

This paper is a preface to the proceedings of the XXX International Conference on Interaction of Intense Energy Fluxes with Matter, which was held in Elbrus settlement, in the Kabardino-Balkar Republic of the Russian Federation, from March 1-6, 2015.

How large is the subducted water flux? New constraints on mantle regassing rates

Science.gov (United States)

Parai, R.; Mukhopadhyay, S.

2012-02-01

Estimates of the subducted water (H2O) flux have been used to discuss the regassing of the mantle over Earth history. However, these estimates vary widely, and some are large enough to have reduced the volume of water in the global ocean by a factor of two over the Phanerozoic. In light of uncertainties in the hydration state of subducting slabs, magma production rates and mantle source water contents, we use a Monte Carlo simulation to set limits on long-term global water cycling and the return flux of water to the deep Earth. Estimates of magma production rates and water contents in primary magmas generated at ocean islands, mid-ocean ridges, arcs and back-arcs are paired with estimates of water entering trenches via subducting oceanic slab in order to construct a model of the deep Earth water cycle. The simulation is constrained by reconstructions of Phanerozoic sea level change, which suggest that ocean volume is near steady-state, though a sea level decrease of up to 360 m may be supported. We provide limits on the return flux of water to the deep Earth over the Phanerozoic corresponding to a near steady-state exosphere (0-100 meter sea level decrease) and a maximum sea level decrease of 360 m. For the near steady-state exosphere, the return flux is 1.4 - 2.0- 0.3+ 0.4 × 1013 mol/yr, corresponding to 2-3% serpentinization in 10 km of lithospheric mantle. The return flux that generates the maximum sea level decrease over the Phanerozoic is 3.5- 0.3+ 0.4 × 1013 mol/yr, corresponding to 5% serpentinization in 10 km of lithospheric mantle. Our estimates of the return flux of water to the mantle are up to 7 times lower than previously suggested. The imbalance between our estimates of the return flux and mantle output flux leads to a low rate of increase in bulk mantle water content of up to 24 ppm/Ga.

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

Model for GCR-particle fluxes in stony meteorites and production rates of cosmogenic nuclides

International Nuclear Information System (INIS)

Reedy, R.C.

1984-01-01

A model is presented for the differential fluxes of galactic-cosmic-ray (GCR) particles with energies above 1 MeV inside any spherical stony meteorite as a function of the meteorite's radius and the sample's depth. This model is based on the Reedy-Arnold equations for the energy-dependent fluxes of GCR particles in the moon and is an extension of flux parameters that were derived for several meteorites of various sizes. This flux is used to calculate the production rates of many cosmogenic nuclides as a function of radius and depth. The peak production rates for most nuclides made by the reactions of energetic GCR particles occur near the centers of meteorites with radii of 40 to 70 g cm -2 . Although the model has some limitations, it reproduces well the basic trends for the depth-dependent production of cosmogenic nuclides in stony meteorites of various radii. These production profiles agree fairly well with measurements of cosmogenic nuclides in meteorites. Some of these production profiles are different than those calculated by others. The chemical dependence of the production rates for several nuclides varies with size and depth. 25 references, 8 figures

Fluxes and exchange rates of radon and oxygen across an air-sea interface

International Nuclear Information System (INIS)

Duenas, C.; Fernandez, M.C.; La Torre, M. de

1986-01-01

The flux of 222 Rn and O 2 from shallow water off the Bay of Malaga has been measured. The mean value of flux of 222 Rn is evaluated to be 74 atoms/m 2 · s. The Bay is a weak source of oxygen to the atmosphere, where the net production of oxygen is found to be 1.82 mol/m 2 · y. Moreover, the gas exchange rates of 222 Rn and O 2 across the air-sea interface has been determined by the radon method. The gas exchange rates and the wind speed have been estimated. (author)

A detailed analysis of inviscid flux splitting algorithms for real gases with equilibrium or finite-rate chemistry

Science.gov (United States)

Shuen, Jian-Shun; Liou, Meng-Sing; Van Leer, Bram

1989-01-01

The extension of the known flux-vector and flux-difference splittings to real gases via rigorous mathematical procedures is demonstrated. Formulations of both equilibrium and finite-rate chemistry for real-gas flows are described, with emphasis on derivations of finite-rate chemistry. Split-flux formulas from other authors are examined. A second-order upwind-based TVD scheme is adopted to eliminate oscillations and to obtain a sharp representation of discontinuities.

Numerical modelling of landscape and sediment flux response to precipitation rate change

Science.gov (United States)

Armitage, John J.; Whittaker, Alexander C.; Zakari, Mustapha; Campforts, Benjamin

2018-02-01

Laboratory-scale experiments of erosion have demonstrated that landscapes have a natural (or intrinsic) response time to a change in precipitation rate. In the last few decades there has been growth in the development of numerical models that attempt to capture landscape evolution over long timescales. However, there is still an uncertainty regarding the validity of the basic assumptions of mass transport that are made in deriving these models. In this contribution we therefore return to a principal assumption of sediment transport within the mass balance for surface processes; we explore the sensitivity of the classic end-member landscape evolution models and the sediment fluxes they produce to a change in precipitation rates. One end-member model takes the mathematical form of a kinetic wave equation and is known as the stream power model, in which sediment is assumed to be transported immediately out of the model domain. The second end-member model is the transport model and it takes the form of a diffusion equation, assuming that the sediment flux is a function of the water flux and slope. We find that both of these end-member models have a response time that has a proportionality to the precipitation rate that follows a negative power law. However, for the stream power model the exponent on the water flux term must be less than one, and for the transport model the exponent must be greater than one, in order to match the observed concavity of natural systems. This difference in exponent means that the transport model generally responds more rapidly to an increase in precipitation rates, on the order of 105 years for post-perturbation sediment fluxes to return to within 50 % of their initial values, for theoretical landscapes with a scale of 100×100 km. Additionally from the same starting conditions, the amplitude of the sediment flux perturbation in the transport model is greater, with much larger sensitivity to catchment size. An important finding is that

Numerical modelling of landscape and sediment flux response to precipitation rate change

Directory of Open Access Journals (Sweden)

J. J. Armitage

2018-02-01

Full Text Available Laboratory-scale experiments of erosion have demonstrated that landscapes have a natural (or intrinsic response time to a change in precipitation rate. In the last few decades there has been growth in the development of numerical models that attempt to capture landscape evolution over long timescales. However, there is still an uncertainty regarding the validity of the basic assumptions of mass transport that are made in deriving these models. In this contribution we therefore return to a principal assumption of sediment transport within the mass balance for surface processes; we explore the sensitivity of the classic end-member landscape evolution models and the sediment fluxes they produce to a change in precipitation rates. One end-member model takes the mathematical form of a kinetic wave equation and is known as the stream power model, in which sediment is assumed to be transported immediately out of the model domain. The second end-member model is the transport model and it takes the form of a diffusion equation, assuming that the sediment flux is a function of the water flux and slope. We find that both of these end-member models have a response time that has a proportionality to the precipitation rate that follows a negative power law. However, for the stream power model the exponent on the water flux term must be less than one, and for the transport model the exponent must be greater than one, in order to match the observed concavity of natural systems. This difference in exponent means that the transport model generally responds more rapidly to an increase in precipitation rates, on the order of 105 years for post-perturbation sediment fluxes to return to within 50 % of their initial values, for theoretical landscapes with a scale of 100×100 km. Additionally from the same starting conditions, the amplitude of the sediment flux perturbation in the transport model is greater, with much larger sensitivity to catchment size. An

Determination of radon flux rates in a uranium mine (Cluff Lake, Saskatchewan)

International Nuclear Information System (INIS)

1989-12-01

The Atomic Energy Control Board contracted SENES Consultants Limited to design and implement a field program at Amok Limited's Cluff Lake uranium mine, with the overall objective of obtaining reliable radon flux data applicable for use in the VENTRAD computer model. The VENTRAD model was developed to model underground mine ventilation systems. To avoid the uncertainties inherent in localized flux measurements made on small surfaces, radon flux measurements were determined through measurement of incremental changes in the concentration of radon between the incoming and outgoing air in selected areas of the underground workings. The locations were selected throughout the mine in both ore and sterile rock. Average radon flux rates measured during three field campaigns were as follows: sterile rock decline 4 pCi/m 2 .second; sterile rock mainway 25 pCi/m 2 .second; worked-out stope 100 pCi/m 2 .second; active work stope 240 pCi/m 2 .second; and work face 14,000 pCi/m 2 .second. Data collected during the three field programs were used to validate the VENTRAD computer model. The results of the validation exercise suggest close agreement between predicted and measured air flow rates and radon concentrations were overestimated for areas immediately impacted by auxiliary ventilation fans and ore transfer mill holes which connect the ore extraction and haulage levels of the mine

Correlation between TCA cycle flux and glucose uptake rate during respiro-fermentative growth of Saccharomyces cerevisiae.

Science.gov (United States)

Heyland, Jan; Fu, Jianan; Blank, Lars M

2009-12-01

Glucose repression of the tricarboxylic acid (TCA) cycle in Saccharomyces cerevisiae was investigated under different environmental conditions using (13)C-tracer experiments. Real-time quantification of the volatile metabolites ethanol and CO(2) allowed accurate carbon balancing. In all experiments with the wild-type, a strong correlation between the rates of growth and glucose uptake was observed, indicating a constant yield of biomass. In contrast, glycerol and acetate production rates were less dependent on the rate of glucose uptake, but were affected by environmental conditions. The glycerol production rate was highest during growth in high-osmolarity medium (2.9 mmol g(-1) h(-1)), while the highest acetate production rate of 2.1 mmol g(-1) h(-1) was observed in alkaline medium of pH 6.9. Under standard growth conditions (25 g glucose l(-1) , pH 5.0, 30 degrees C) S. cerevisiae had low fluxes through the pentose phosphate pathway and the TCA cycle. A significant increase in TCA cycle activity from 0.03 mmol g(-1) h(-1) to about 1.7 mmol g(-1) h(-1) was observed when S. cerevisiae grew more slowly as a result of environmental perturbations, including unfavourable pH values and sodium chloride stress. Compared to experiments with high glucose uptake rates, the ratio of CO(2) to ethanol increased more than 50 %, indicating an increase in flux through the TCA cycle. Although glycolysis and the ethanol production pathway still exhibited the highest fluxes, the net flux through the TCA cycle increased significantly with decreasing glucose uptake rates. Results from experiments with single gene deletion mutants partially impaired in glucose repression (hxk2, grr1) indicated that the rate of glucose uptake correlates with this increase in TCA cycle flux. These findings are discussed in the context of regulation of glucose repression.

High rates of energy expenditure and water flux in free-ranging Point Reyes mountain beavers Aplodontia rufa phaea

Science.gov (United States)

Crocker, D.E.; Kofahl, N.; Fellers, G.D.; Gates, N.B.; Houser, D.S.

2007-01-01

We measured water flux and energy expenditure in free-ranging Point Reyes mountain beavers Aplodontia rufa phaea by using the doubly labeled water method. Previous laboratory investigations have suggested weak urinary concentrating ability, high rates of water flux, and low basal metabolic rates in this species. However, free-ranging measurements from hygric mammals are rare, and it is not known how these features interact in the environment. Rates of water flux (210 ?? 32 mL d-1) and field metabolic rates (1,488 ?? 486 kJ d-1) were 159% and 265%, respectively, of values predicted by allometric equations for similar-sized herbivores. Mountain beavers can likely meet their water needs through metabolic water production and preformed water in food and thus remain in water balance without access to free water. Arginine-vasopressin levels were strongly correlated with rates of water flux and plasma urea : creatinine ratios, suggesting an important role for this hormone in regulating urinary water loss in mountain beavers. High field metabolic rates may result from cool burrow temperatures that are well below lower critical temperatures measured in previous laboratory studies and suggest that thermoregulation costs may strongly influence field energetics and water flux in semifossorial mammals. ?? 2007 by The University of Chicago. All rights reserved.

Fluxes of Ca2+ and K+ are required for the listeriolysin O-dependent internalization pathway of Listeria monocytogenes.

Science.gov (United States)

Vadia, Stephen; Seveau, Stephanie

2014-03-01

Listeria monocytogenes is responsible for the life-threatening food-borne disease listeriosis. This disease mainly affects elderly and immunocompromised individuals, causing bacteremia and meningoencephalitis. In pregnant women, L. monocytogenes infection leads to abortion and severe infection of the fetus or newborn. The L. monocytogenes intracellular life cycle is critical for pathogenesis. Previous studies have established that the major virulence factor of L. monocytogenes, the pore-forming toxin listeriolysin O (LLO), is sufficient to induce L. monocytogenes internalization into human epithelial cell lines. This internalization pathway strictly requires the formation of LLO pores in the plasma membrane and can be stimulated by the heterologous pore-forming toxin pneumolysin, suggesting that LLO acts nonspecifically by forming transmembrane pores. The present work tested the hypothesis that Ca2+ and K+ fluxes subsequent to perforation by LLO control L. monocytogenes internalization. We report that L. monocytogenes perforates the host cell plasma membrane in an LLO-dependent fashion at the early stage of invasion. In response to perforation, host cells undergo Ca2+ -dependent but K+ -independent resealing of their plasma membrane. In contrast to the plasma membrane resealing process, LLO-induced L. monocytogenes internalization requires both Ca2+ and K+ fluxes. Further linking ion fluxes to bacterial internalization, treating cells with a combination of Ca2+ and K+ ionophores but not with individual ionophores is sufficient to induce efficient internalization of large cargoes, such as 1-μm polystyrene beads and bacteria. We propose that LLO-induced L. monocytogenes internalization requires a Ca2+ - and K+ -dependent internalization pathway that is mechanistically distinct from the process of plasma membrane resealing.

Investigation of high flux test module for the international fusion materials irradiation facilities (IFMIF)

International Nuclear Information System (INIS)

Miyashita, Makoto; Sugimoto, Masayoshi; Yutani, Toshiaki

2007-03-01

This report describes investigation on structure of a high neutron flux test module (HFTM) for the International Fusion Materials Irradiation Facilities (IFMIF). The HFTM is aimed for neutron irradiation of a specimen in a high neutron flux domain of the test cell for irradiation ground of IFMIF. We investigated the overall structure of the HFTM that was able to include specimens in a rig and thermocouple arrangement, an interface of control signal and support structure. Moreover, pressure and the amount of the bend in the module vessel (a rectangular section pressure vessel) were calculated. The module vessel did a rectangular section from limitation of a high neutron flux domain. Also, we investigated damage of thermocouples under neutron irradiation, which was a temperature sensor of irradiation materials temperature control demanded high precision. Based on these results, drawings on the HTFM structure. (author)

Radiological characterization of the pressure vessel internals of the BNL High Flux Beam Reactor.

Science.gov (United States)

Holden, Norman E; Reciniello, Richard N; Hu, Jih-Perng

2004-08-01

In preparation for the eventual decommissioning of the High Flux Beam Reactor after the permanent removal of its fuel elements from the Brookhaven National Laboratory, measurements and calculations of the decay gamma-ray dose-rate were performed in the reactor pressure vessel and on vessel internal structures such as the upper and lower thermal shields, the Transition Plate, and the Control Rod blades. Measurements of gamma-ray dose rates were made using Red Perspex polymethyl methacrylate high-dose film, a Radcal "peanut" ion chamber, and Eberline's RO-7 high-range ion chamber. As a comparison, the Monte Carlo MCNP code and MicroShield code were used to model the gamma-ray transport and dose buildup. The gamma-ray dose rate at 8 cm above the center of the Transition Plate was measured to be 160 Gy h (using an RO-7) and 88 Gy h at 8 cm above and about 5 cm lateral to the Transition Plate (using Red Perspex film). This compares with a calculated dose rate of 172 Gy h using Micro-Shield. The gamma-ray dose rate was 16.2 Gy h measured at 76 cm from the reactor core (using the "peanut" ion chamber) and 16.3 Gy h at 87 cm from the core (using Red Perspex film). The similarity of dose rates measured with different instruments indicates that using different methods and instruments is acceptable if the measurement (and calculation) parameters are well defined. Different measurement techniques may be necessary due to constraints such as size restrictions.

Electron and Positron Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station

Science.gov (United States)

Aguilar, M.; Aisa, D.; Alvino, A.; Ambrosi, G.; Andeen, K.; Arruda, L.; Attig, N.; Azzarello, P.; Bachlechner, A.; Barao, F.; Barrau, A.; Barrin, L.; Bartoloni, A.; Basara, L.; Battarbee, M.; Battiston, R.; Bazo, J.; Becker, U.; Behlmann, M.; Beischer, B.; Berdugo, J.; Bertucci, B.; Bigongiari, G.; Bindi, V.; Bizzaglia, S.; Bizzarri, M.; Boella, G.; de Boer, W.; Bollweg, K.; Bonnivard, V.; Borgia, B.; Borsini, S.; Boschini, M. J.; Bourquin, M.; Burger, J.; Cadoux, F.; Cai, X. D.; Capell, M.; Caroff, S.; Casaus, J.; Cascioli, V.; Castellini, G.; Cernuda, I.; Cervelli, F.; Chae, M. J.; Chang, Y. H.; Chen, A. I.; Chen, H.; Cheng, G. M.; Chen, H. S.; Cheng, L.; Chikanian, A.; Chou, H. Y.; Choumilov, E.; Choutko, V.; Chung, C. H.; Clark, C.; Clavero, R.; Coignet, G.; Consolandi, C.; Contin, A.; Corti, C.; Coste, B.; Cui, Z.; Dai, M.; Delgado, C.; Della Torre, S.; Demirköz, M. B.; Derome, L.; Di Falco, S.; Di Masso, L.; Dimiccoli, F.; Díaz, C.; von Doetinchem, P.; Du, W. J.; Duranti, M.; D'Urso, D.; Eline, A.; Eppling, F. J.; Eronen, T.; Fan, Y. Y.; Farnesini, L.; Feng, J.; Fiandrini, E.; Fiasson, A.; Finch, E.; Fisher, P.; Galaktionov, Y.; Gallucci, G.; García, B.; García-López, R.; Gast, H.; Gebauer, I.; Gervasi, M.; Ghelfi, A.; Gillard, W.; Giovacchini, F.; Goglov, P.; Gong, J.; Goy, C.; Grabski, V.; Grandi, D.; Graziani, M.; Guandalini, C.; Guerri, I.; Guo, K. H.; Habiby, M.; Haino, S.; Han, K. C.; He, Z. H.; Heil, M.; Hoffman, J.; Hsieh, T. H.; Huang, Z. C.; Huh, C.; Incagli, M.; Ionica, M.; Jang, W. Y.; Jinchi, H.; Kanishev, K.; Kim, G. N.; Kim, K. S.; Kirn, Th.; Kossakowski, R.; Kounina, O.; Kounine, A.; Koutsenko, V.; Krafczyk, M. S.; Kunz, S.; La Vacca, G.; Laudi, E.; Laurenti, G.; Lazzizzera, I.; Lebedev, A.; Lee, H. T.; Lee, S. C.; Leluc, C.; Li, H. L.; Li, J. Q.; Li, Q.; Li, Q.; Li, T. X.; Li, W.; Li, Y.; Li, Z. H.; Li, Z. Y.; Lim, S.; Lin, C. H.; Lipari, P.; Lippert, T.; Liu, D.; Liu, H.; Lomtadze, T.; Lu, M. J.; Lu, Y. S.; Luebelsmeyer, K.; Luo, F.; Luo, J. Z.; Lv, S. S.; Majka, R.; Malinin, A.; Mañá, C.; Marín, J.; Martin, T.; Martínez, G.; Masi, N.; Maurin, D.; Menchaca-Rocha, A.; Meng, Q.; Mo, D. C.; Morescalchi, L.; Mott, P.; Müller, M.; Ni, J. Q.; Nikonov, N.; Nozzoli, F.; Nunes, P.; Obermeier, A.; Oliva, A.; Orcinha, M.; Palmonari, F.; Palomares, C.; Paniccia, M.; Papi, A.; Pedreschi, E.; Pensotti, S.; Pereira, R.; Pilo, F.; Piluso, A.; Pizzolotto, C.; Plyaskin, V.; Pohl, M.; Poireau, V.; Postaci, E.; Putze, A.; Quadrani, L.; Qi, X. M.; Rancoita, P. G.; Rapin, D.; Ricol, J. S.; Rodríguez, I.; Rosier-Lees, S.; Rozhkov, A.; Rozza, D.; Sagdeev, R.; Sandweiss, J.; Saouter, P.; Sbarra, C.; Schael, S.; Schmidt, S. M.; Schuckardt, D.; von Dratzig, A. Schulz; Schwering, G.; Scolieri, G.; Seo, E. S.; Shan, B. S.; Shan, Y. H.; Shi, J. Y.; Shi, X. Y.; Shi, Y. M.; Siedenburg, T.; Son, D.; Spada, F.; Spinella, F.; Sun, W.; Sun, W. H.; Tacconi, M.; Tang, C. P.; Tang, X. W.; Tang, Z. C.; Tao, L.; Tescaro, D.; Ting, Samuel C. C.; Ting, S. M.; Tomassetti, N.; Torsti, J.; Türkoǧlu, C.; Urban, T.; Vagelli, V.; Valente, E.; Vannini, C.; Valtonen, E.; Vaurynovich, S.; Vecchi, M.; Velasco, M.; Vialle, J. P.; Wang, L. Q.; Wang, Q. L.; Wang, R. S.; Wang, X.; Wang, Z. X.; Weng, Z. L.; Whitman, K.; Wienkenhöver, J.; Wu, H.; Xia, X.; Xie, M.; Xie, S.; Xiong, R. Q.; Xin, G. M.; Xu, N. S.; Xu, W.; Yan, Q.; Yang, J.; Yang, M.; Ye, Q. H.; Yi, H.; Yu, Y. J.; Yu, Z. Q.; Zeissler, S.; Zhang, J. H.; Zhang, M. T.; Zhang, X. B.; Zhang, Z.; Zheng, Z. M.; Zhuang, H. L.; Zhukov, V.; Zichichi, A.; Zimmermann, N.; Zuccon, P.; Zurbach, C.; AMS Collaboration

2014-09-01

Precision measurements by the Alpha Magnetic Spectrometer on the International Space Station of the primary cosmic-ray electron flux in the range 0.5 to 700 GeV and the positron flux in the range 0.5 to 500 GeV are presented. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron flux and the positron flux change their behavior at ˜30 GeV but the fluxes are significantly different in their magnitude and energy dependence. Between 20 and 200 GeV the positron spectral index is significantly harder than the electron spectral index. The determination of the differing behavior of the spectral indices versus energy is a new observation and provides important information on the origins of cosmic-ray electrons and positrons.

Solar Flux Deposition And Heating Rates In Jupiter's Atmosphere

Science.gov (United States)

Perez-Hoyos, Santiago; Sánchez-Lavega, A.

2009-09-01

We discuss here the solar downward net flux in the 0.25 - 2.5 µm range in the atmosphere of Jupiter and the associated heating rates under a number of vertical cloud structure scenarios focusing in the effect of clouds and hazes. Our numerical model is based in the doubling-adding technique to solve the radiative transfer equation and it includes gas absorption by CH4, NH3 and H2, in addition to Rayleigh scattering by a mixture of H2 plus He. Four paradigmatic Jovian regions have been considered (hot-spots, belts, zones and Polar Regions). The hot-spots are the most transparent regions with downward net fluxes of 2.5±0.5 Wm-2 at the 6 bar level. The maximum solar heating is 0.04±0.01 K/day and occurs above 1 bar. Belts and zones characterization result in a maximum net downward flux of 0.5 Wm-2 at 2 bar and 0.015 Wm-2 at 6 bar. Heating is concentrated in the stratospheric and tropospheric hazes. Finally, Polar Regions are also explored and the results point to a considerable stratospheric heating of 0.04±0.02 K/day. In all, these calculations suggest that the role of the direct solar forcing in the Jovian atmospheric dynamics is limited to the upper 1 - 2 bar of the atmosphere except in the hot-spot areas. Acknowledgments: This work has been funded by Spanish MEC AYA2006-07735 with FEDER support and Grupos Gobierno Vasco IT-464-07.

American National Standard: neutron and gamma-ray flux-to-dose rate factors

International Nuclear Information System (INIS)

Anon.

1977-01-01

This Standard presents data recommended for computing biological dose rates due to neutron and gamma-ray radiation fields. Neutron flux-to-dose-rate conversion factors for energies from 2.5 x 10 -8 to 20 MeV are given; the energy range for the gamma-ray conversion factors is 0.01 to 15 MeV. Specifically, this Standard is intended for use by shield designers to calculate wholebody dose rates to radiation workers and the general public. Establishing dose-rate limits is outside the scope of this Standard. Use of this Standard in cases where the dose equivalents are far in excess of occupational exposure guidelines is not recommended

Magma fluxes and recurreance rate of eruptions at Nevado de Toluca volcano (Mexico)

Science.gov (United States)

Weber, Gregor; Probst, Line; Arce, José L.; Caricchi, Luca

2017-04-01

Forecasting the frequency and size of volcanic eruptions is a long-term goal for hazard mitigation. The frequency at which a given crustal magmatic system is driven towards a critical state and the magnitude of the resulting volcanic events are linked to the supply rate of fresh magma, crustal properties, and tectonic setting. Our ability to forecast the recurrence rate of eruptions is hampered by the lack of data on key variables such as the average magma flux locally and globally. The aim of this project is to identify the average magma supply rate and injection frequency for eruptions of different magnitude and eruptive style. We centred our study at Nevado de Toluca in Mexico, a subduction-related volcano with an eruptive history spanning about 1.5 million years of comparatively well documented effusive and explosive eruptions dominantly of dacitic composition. We carry out in-situ high precision zircon geochronology for a sequence of eruptions of different magnitude to obtain a distribution of crystal ages from which average crustal magma fluxes can be calculated. Eruptive fluxes will be constrained by extracting lava flow volumes from a digital elevation model. A combination of whole rock and mineral chemistry will provide quantitative insights on petrogenetic processes and on the frequency at which intensive parameters changed within the magma reservoir before the eruptions. Our results will be integrated in a global database including other volcanic systems and literature data to attempt to identify similarities and differences between magmatic reservoirs feeding volcanic eruptions of different magnitude. The final target of this project is to identify the physical factors controlling the recurrence rate of volcanic eruptions at regional and global scale.

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.

Electron and Positron Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station

CERN Document Server

Aguilar, M; Alvino, A; Ambrosi, G; Andeen, K; Arruda, L; Attig, N; Azzarello, P; Bachlechner, A; Barao, F; Barrau, A; Barrin, L; Bartoloni, A; Basara, L; Battarbee, M; Battiston, R; Bazo, J; Becker, U; Behlmann, M; Beischer, B; Berdugo, J; Bertucci, B; Bigongiari, G; Bindi, V; Bizzaglia, S; Bizzarri, M; Boella, G; de Boer, W; Bollweg, K; Bonnivard, V; Borgia, B; Borsini, S; Boschini, M J; Bourquin, M; Burger, J; Cadoux, F; Cai, X D; Capell, M; Caroff, S; Casaus, J; Cascioli, V; Castellini, G; Cernuda, I; Cervelli, F; Chae, M J; Chang, Y H; Chen, A I; Chen, H; Cheng, G M; Chen, H S; Cheng, L; Chikanian, A; Chou, H Y; Choumilov, E; Choutko, V; Chung, C H; Clark, C; Clavero, R; Coignet, G; Consolandi, C; Contin, A; Corti, C; Coste, B; Cui, Z; Dai, M; Delgado, C; Della Torre, S; Demirköz, M B; Derome, L; Di Falco, S; Di Masso, L; Dimiccoli, F; Díaz, C; von Doetinchem, P; Du, W J; Duranti, M; D’Urso, D; Eline, A; Eppling, F J; Eronen, T; Fan, Y Y; Farnesini, L; Feng, J; Fiandrini, E; Fiasson, A; Finch, E; Fisher, P; Galaktionov, Y; Gallucci, G; García, B; García-López, R; Gast, H; Gebauer, I; Gervasi, M; Ghelfi, A; Gillard, W; Giovacchini, F; Goglov, P; Gong, J; Goy, C; Grabski, V; Grandi, D; Graziani, M; Guandalini, C; Guerri, I; Guo, K H; Habiby, M; Haino, S; Han, K C; He, Z H; Heil, M; Hoffman, J; Hsieh, T H; Huang, Z C; Huh, C; Incagli, M; Ionica, M; Jang, W Y; Jinchi, H; Kanishev, K; Kim, G N; Kim, K S; Kirn, Th; Kossakowski, R; Kounina, O; Kounine, A; Koutsenko, V; Krafczyk, M S; Kunz, S; La Vacca, G; Laudi, E; Laurenti, G; Lazzizzera, I; Lebedev, A; Lee, H T; Lee, S C; Leluc, C; Li, H L; Li, J Q; Li, Q; Li, Q; Li, T X; Li, W; Li, Y; Li, Z H; Li, Z Y; Lim, S; Lin, C H; Lipari, P; Lippert, T; Liu, D; Liu, H; Lomtadze, T; Lu, M J; Lu, Y S; Luebelsmeyer, K; Luo, F; Luo, J Z; Lv, S S; Majka, R; Malinin, A; Mañá, C; Marín, J; Martin, T; Martínez, G; Masi, N; Maurin, D; Menchaca-Rocha, A; Meng, Q; Mo, D C; Morescalchi, L; Mott, P; Müller, M; Ni, J Q; Nikonov, N; Nozzoli, F; Nunes, P; Obermeier, A; Oliva, A; Orcinha, M; Palmonari, F; Palomares, C; Paniccia, M; Papi, A; Pedreschi, E; Pensotti, S; Pereira, R; Pilo, F; Piluso, A; Pizzolotto, C; Plyaskin, V; Pohl, M; Poireau, V; Postaci, E; Putze, A; Quadrani, L; Qi, X M; Rancoita, P G; Rapin, D; Ricol, J S; Rodríguez, I; Rosier-Lees, S; Rozhkov, A; Rozza, D; Sagdeev, R; Sandweiss, J; Saouter, P; Sbarra, C; Schael, S; Schmidt, S M; Schuckardt, D; Schulz von Dratzig, A; Schwering, G; Scolieri, G; Seo, E S; Shan, B S; Shan, Y H; Shi, J Y; Shi, X Y; Shi, Y M; Siedenburg, T; Son, D; Spada, F; Spinella, F; Sun, W; Sun, W H; Tacconi, M; Tang, C P; Tang, X W; Tang, Z C; Tao, L; Tescaro, D; Ting, Samuel C C; Ting, S M; Tomassetti, N; Torsti, J; Türkoğlu, C; Urban, T; Vagelli, V; Valente, E; Vannini, C; Valtonen, E; Vaurynovich, S; Vecchi, M; Velasco, M; Vialle, J P; Wang, L Q; Wang, Q L; Wang, R S; Wang, X; Wang, Z X; Weng, Z L; Whitman, K; Wienkenhöver, J; Wu, H; Xia, X; Xie, M; Xie, S; Xiong, R Q; Xin, G M; Xu, N S; Xu, W; Yan, Q; Yang, J; Yang, M; Ye, Q H; Yi, H; Yu, Y J; Yu, Z Q; Zeissler, S; Zhang, J H; Zhang, M T; Zhang, X B; Zhang, Z; Zheng, Z M; Zhuang, H L; Zhukov, V; Zichichi, A; Zimmermann, N; Zuccon, P; Zurbach, C

2014-01-01

Precision measurements by the Alpha Magnetic Spectrometer on the International Space Station of the primary cosmic-ray electron flux in the range 0.5 to 700 GeV and the positron flux in the range 0.5 to 500 GeV are presented. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron flux and the positron flux change their behavior at ∼30  GeV but the fluxes are significantly different in their magnitude and energy dependence. Between 20 and 200 GeV the positron spectral index is significantly harder than the electron spectral index. The determination of the differing behavior of the spectral indices versus energy is a new observation and provides important information on the origins of cosmic-ray electrons and positrons.

Convective Heat Transfer Scaling of Ignition Delay and Burning Rate with Heat Flux and Stretch Rate in the Equivalent Low Stretch Apparatus

Science.gov (United States)

Olson, Sandra

2011-01-01

To better evaluate the buoyant contributions to the convective cooling (or heating) inherent in normal-gravity material flammability test methods, we derive a convective heat transfer correlation that can be used to account for the forced convective stretch effects on the net radiant heat flux for both ignition delay time and burning rate. The Equivalent Low Stretch Apparatus (ELSA) uses an inverted cone heater to minimize buoyant effects while at the same time providing a forced stagnation flow on the sample, which ignites and burns as a ceiling fire. Ignition delay and burning rate data is correlated with incident heat flux and convective heat transfer and compared to results from other test methods and fuel geometries using similarity to determine the equivalent stretch rates and thus convective cooling (or heating) rates for those geometries. With this correlation methodology, buoyant effects inherent in normal gravity material flammability test methods can be estimated, to better apply the test results to low stretch environments relevant to spacecraft material selection.

5th International Congress on Energy Fluxes and Radiation Effects 2016

International Nuclear Information System (INIS)

2017-01-01

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

Mass transfer inside a flux hood for the sampling of gaseous emissions from liquid surfaces - Experimental assessment and emission rate rescaling

Science.gov (United States)

Prata, Ademir A.; Lucernoni, Federico; Santos, Jane M.; Capelli, Laura; Sironi, Selena; Le-Minh, Nhat; Stuetz, Richard M.

2018-04-01

This study assesses the mass transfer of compounds inside the US EPA flux hood, one of the enclosure devices most commonly employed for the direct measurement of atmospheric emissions from liquid surfaces in wastewater treatment plants (WWTPs). Experiments comprised the evaporation of water and the volatilisation of a range of volatile organic compounds (VOCs). Special attention was given to the evaluation of the mass transfer coefficients in the microenvironment created by the flux hood and the effects of concentration build up in the hood's headspace. The VOCs emission rates and the water evaporation rates generally increased with the sweep air flow rate, as did the mass transfer coefficients for all compounds. The emission of compounds whose volatilisation is significantly influenced by the gas phase was greatly affected by concentration build up, whereas this effect was not significant for liquid phase-controlled compounds. The gas-film mass transfer coefficient (kG) estimated inside the US EPA flux hood was of the same order as the respective kG reported in the literature for wind tunnel-type devices, but the emission rates measured by the flux hood can be expected to be lower, due to the concentration build-up. Compared against an emission model for the passive surfaces in WWTPs, the mass transfer of acetic acid (representing a gas phase-dominated compound) inside the US EPA flux hood was equivalent to conditions of wind speeds at 10 m height (U10) of 0.27, 0.51 and 0.99 m s-1, respectively, for sweep air flow rates of 2, 5 and 10 L min-1. On the other hand, for higher wind speeds, the emission rates of gas phase-controlled compounds obtained with the flux hood can be considerably underestimated: for instance, at U10 = 5 m s-1, the emission rates of acetic acid inside the flux hood would be approximately 23, 12 and 6 times lower than the emission rates in the field, for sweep air flow rates of 2, 5 and 10 L min-1, respectively. A procedure is presented in

Thermal resistance of a convectively cooled plate with applied heat flux and variable internal heat generation

International Nuclear Information System (INIS)

Venkataraman, N.S.; Cardoso, H.P.; Oliveira Filho, O.B. de

1981-01-01

The conductive heat transfer in a rectangular plate with nonuniform internal heat generation, with one end convectively cooled and a part of the opposite end subjected to external heat flux is considered. The remaining part of this end as well as the other two sides are thermally insulated. The governing differential equation is solved by a finite difference scheme. The variation of the thermal resistance with Biot modulus, the plate geometry, the internal heat generation parameter and the type of profile of internal heat generation is discussed. (author) [pt

Utilizing the Fast Flux Test Facility for international passive safety testing

International Nuclear Information System (INIS)

Shen, P.K.; Padilla, A.; Lucoff, D.M.; Waltar, A.E.

1991-01-01

A two-phased approach has been undertaken in the Fast Flux Test Facility (FFTF) to conduct passive safety testing. Phase I (1986 to 1987) was structured to obtain an initial understanding of the reactivity feedback components. The planned Phase II (1992 to 1993) international program will extend the testing to include static and dynamic feedback measurements, transient and demonstration tests, and gas expansion module (GEM) reactivity tests. The primary objective is to meet the needs for safety analysis code validation, with particular emphasis on reducing the uncertainties associated with structure reactivity feedback. Program scope and predicted FFTF responses are discussed and illustrated. (author)

Statistical analysis of error rate of large-scale single flux quantum logic circuit by considering fluctuation of timing parameters

International Nuclear Information System (INIS)

Yamanashi, Yuki; Masubuchi, Kota; Yoshikawa, Nobuyuki

2016-01-01

The relationship between the timing margin and the error rate of the large-scale single flux quantum logic circuits is quantitatively investigated to establish a timing design guideline. We observed that the fluctuation in the set-up/hold time of single flux quantum logic gates caused by thermal noises is the most probable origin of the logical error of the large-scale single flux quantum circuit. The appropriate timing margin for stable operation of the large-scale logic circuit is discussed by taking the fluctuation of setup/hold time and the timing jitter in the single flux quantum circuits. As a case study, the dependence of the error rate of the 1-million-bit single flux quantum shift register on the timing margin is statistically analyzed. The result indicates that adjustment of timing margin and the bias voltage is important for stable operation of a large-scale SFQ logic circuit.

Statistical analysis of error rate of large-scale single flux quantum logic circuit by considering fluctuation of timing parameters

Energy Technology Data Exchange (ETDEWEB)

Yamanashi, Yuki, E-mail: yamanasi@ynu.ac.jp [Department of Electrical and Computer Engineering, Yokohama National University, Tokiwadai 79-5, Hodogaya-ku, Yokohama 240-8501 (Japan); Masubuchi, Kota; Yoshikawa, Nobuyuki [Department of Electrical and Computer Engineering, Yokohama National University, Tokiwadai 79-5, Hodogaya-ku, Yokohama 240-8501 (Japan)

2016-11-15

The relationship between the timing margin and the error rate of the large-scale single flux quantum logic circuits is quantitatively investigated to establish a timing design guideline. We observed that the fluctuation in the set-up/hold time of single flux quantum logic gates caused by thermal noises is the most probable origin of the logical error of the large-scale single flux quantum circuit. The appropriate timing margin for stable operation of the large-scale logic circuit is discussed by taking the fluctuation of setup/hold time and the timing jitter in the single flux quantum circuits. As a case study, the dependence of the error rate of the 1-million-bit single flux quantum shift register on the timing margin is statistically analyzed. The result indicates that adjustment of timing margin and the bias voltage is important for stable operation of a large-scale SFQ logic circuit.

Eddy covariance N2O flux measurements at low flux rates: results from the InGOS campaign in a Danish willow field.

Science.gov (United States)

Ibrom, Andreas; Brümmer, Christian; Hensen, Arjan; van Asperen, Hella; Carter, Mette S.; Gasche, Rainer; Famulari, Daniela; Kutsch, Werner; Pilegaard, Kim; Ambus, Per

2014-05-01

rates. All three EC systems showed 30 min. flux values varying around zero nmol m-2 s-1. This noise was considerably lower in the EC systems that used QCL analysers. The maximum daily averages of the uncorrected fluxes from two of the EC systems reached 0.26 (ICOS/HS50) and 0.28 (QCL/R3) nmol m-2 s-1.Spectral correction increased the flux estimates up to, e.g., 180% equivalent to 0.54 nmol m-2 s-1. The flux estimates from the soil chambers were with one exception higher than the flux estimates obtained from the EC systems with highest daily averages ranging from 0.1 up to 2 nmol m-2 s-1. These large differences were unexpected, because at least two of the EC systems were shown to accurately measure fluxes at such higher levels at another InGOS campaign in a fertilised Scottish grazed meadow. We use spectral analysis to examine the raw data for the effects of sensor noise on the flux estimates and discuss strategies on how to correct or account for it. Furthermore possible causes for the observed differences between the observed EC and chamber flux estimates will be discussed.

A New Method to Calculate Internal Rate of Return

Directory of Open Access Journals (Sweden)

azadeh zandi

2015-09-01

Full Text Available A number of methods have been developed to choose the best capital investment projects such as net present value, internal rate of return and etc. Internal rate of return method is probably the most popular method among managers and investors. But despite the popularity there are serious drawbacks and limitations in this method. After decades of efforts made by economists and experts to improve the method and its shortcomings, Magni in 2010 has revealed a new approach that can solves the most of internal rate of return method problems. This paper present a new method which is originated from Magni’s approach but has much more simple calculations and can resolve all the drawbacks of internal rate of return method.

Integrated leak rate test of the FFTF [Fast Flux Test Facility] containment vessel

International Nuclear Information System (INIS)

Grygiel, M.L.; Davis, R.H.; Polzin, D.L.; Yule, W.D.

1987-04-01

The third integrated leak rate test (ILRT) performed at the Fast Flux Test Facility (FFTF) demonstrated that effective leak rate measurements could be obtained at a pressure of 2 psig. In addition, innovative data reduction methods demonstrated the ability to accurately account for diurnal variations in containment pressure and temperature. Further development of methods used in this test indicate significant savings in the time and effort required to perform an ILRT on Liquid Metal Reactor Systems with consequent reduction in test costs

Scaling in situ cosmogenic nuclide production rates using analytical approximations to atmospheric cosmic-ray fluxes

Science.gov (United States)

Lifton, Nathaniel; Sato, Tatsuhiko; Dunai, Tibor J.

2014-01-01

Several models have been proposed for scaling in situ cosmogenic nuclide production rates from the relatively few sites where they have been measured to other sites of interest. Two main types of models are recognized: (1) those based on data from nuclear disintegrations in photographic emulsions combined with various neutron detectors, and (2) those based largely on neutron monitor data. However, stubborn discrepancies between these model types have led to frequent confusion when calculating surface exposure ages from production rates derived from the models. To help resolve these discrepancies and identify the sources of potential biases in each model, we have developed a new scaling model based on analytical approximations to modeled fluxes of the main atmospheric cosmic-ray particles responsible for in situ cosmogenic nuclide production. Both the analytical formulations and the Monte Carlo model fluxes on which they are based agree well with measured atmospheric fluxes of neutrons, protons, and muons, indicating they can serve as a robust estimate of the atmospheric cosmic-ray flux based on first principles. We are also using updated records for quantifying temporal and spatial variability in geomagnetic and solar modulation effects on the fluxes. A key advantage of this new model (herein termed LSD) over previous Monte Carlo models of cosmogenic nuclide production is that it allows for faster estimation of scaling factors based on time-varying geomagnetic and solar inputs. Comparing scaling predictions derived from the LSD model with those of previously published models suggest potential sources of bias in the latter can be largely attributed to two factors: different energy responses of the secondary neutron detectors used in developing the models, and different geomagnetic parameterizations. Given that the LSD model generates flux spectra for each cosmic-ray particle of interest, it is also relatively straightforward to generate nuclide-specific scaling

Exchange rate volatility and international trade: The option approach

OpenAIRE

Franke, Günter

1986-01-01

Usually it is argued that an increase in exchange rate volatility reduces the volume of international trade since trading firms are risk averse. This paper shows for risk neutral firms that the expected international trade volume in standardized commodities grows with exchange rate volatility. The firms adjust their trade volume to the exchange rate level. The more favorable the exchange rate is, the higher is the export volume. If the rate drops below some level, exports are stopped. Thus in...

MURLI, 1-D Flux, Reaction Rate in Cylindrical Geometry Thermal Reactor Lattice by Transport

International Nuclear Information System (INIS)

Huria, H.C.

1985-01-01

1 - Description of problem or function: MURLI is an integral transport theory code to calculate fluxes and reaction rates in one- dimensional cylindrical geometry lattice cells of a thermal reactor. For a specified buckling, it computes k-effective using few-group diffusion theory and a few-group collapsed set of Cross sections. The code can optionally be used to solve a first order differential equation for the number density of fissile, fertile and fission product nuclei as a function of time, and to recalculate fluxes, reaction rates and k-effective at different stages of burnup. A 27-group cross section data library is included. There are four pseudo-fission products each associated with the decay chains of plutonium and uranium isotopes in addition to Rh-105, Xe-135, Np-239, U-236, Am-241, Am-242 and Am-243. There is also data for one lumped pseudo-fission product. 2 - Method of solution: Multiple collision probabilities and escape probabilities are calculated for each cylindrical shell region assuming protons are born uniformly and isotropically over the entire region volume. The equations of integral transport theory can then be solved for neutron flux. The first order differential burnup equation is solved by a fourth order Runge-Kutta method. 3 - Restrictions on the complexity of the problem: There are maxima of 8 fissionable elements, 8 resonant elements, and 20 spatial regions

A new lattice hydrodynamic model based on control method considering the flux change rate and delay feedback signal

Science.gov (United States)

Qin, Shunda; Ge, Hongxia; Cheng, Rongjun

2018-02-01

In this paper, a new lattice hydrodynamic model is proposed by taking delay feedback and flux change rate effect into account in a single lane. The linear stability condition of the new model is derived by control theory. By using the nonlinear analysis method, the mKDV equation near the critical point is deduced to describe the traffic congestion. Numerical simulations are carried out to demonstrate the advantage of the new model in suppressing traffic jam with the consideration of flux change rate effect in delay feedback model.

Fieldable computer system for determining gamma-ray pulse-height distributions, flux spectra, and dose rates from Little Boy

International Nuclear Information System (INIS)

Moss, C.E.; Lucas, M.C.; Tisinger, E.W.; Hamm, M.E.

1984-01-01

Our system consists of a LeCroy 3500 data acquisition system with a built-in CAMAC crate and eight bismuth-germanate detectors 7.62 cm in diameter and 7.62 cm long. Gamma-ray pulse-height distributions are acquired simultaneously for up to eight positions. The system was very carefully calibrated and characterized from 0.1 to 8.3 MeV using gamma-ray spectra from a variety of radioactive sources. By fitting the pulse-height distributions from the sources with a function containing 17 parameters, we determined theoretical repsonse functions. We use these response functions to unfold the distributions to obtain flux spectra. A flux-to-dose-rate conversion curve based on the work of Dimbylow and Francis is then used to obtain dose rates. Direct use of measured spectra and flux-to-dose-rate curves to obtain dose rates avoids the errors that can arise from spectrum dependence in simple gamma-ray dosimeter instruments. We present some gamma-ray doses for the Little Boy assembly operated at low power. These results can be used to determine the exposures of the Hiroshima survivors and thus aid in the establishment of radation exposure limits for the nuclear industry

Sinking rates and ballast composition of particles in the Atlantic Ocean: implications for the organic carbon fluxes to the deep ocean

Science.gov (United States)

Fischer, G.; Karakaş, G.

2009-01-01

The flux of materials to the deep sea is dominated by larger, organic-rich particles with sinking rates varying between a few meters and several hundred meters per day. Mineral ballast may regulate the transfer of organic matter and other components by determining the sinking rates, e.g. via particle density. We calculated particle sinking rates from mass flux patterns and alkenone measurements applying the results of sediment trap experiments from the Atlantic Ocean. We have indication for higher particle sinking rates in carbonate-dominated production systems when considering both regional and seasonal data. During a summer coccolithophorid bloom in the Cape Blanc coastal upwelling off Mauritania, particle sinking rates reached almost 570 m per day, most probably due the fast sedimentation of densely packed zooplankton fecal pellets, which transport high amounts of organic carbon associated with coccoliths to the deep ocean despite rather low production. During the recurring winter-spring blooms off NW Africa and in opal-rich production systems of the Southern Ocean, sinking rates of larger particles, most probably diatom aggregates, showed a tendency to lower values. However, there is no straightforward relationship between carbonate content and particle sinking rates. This could be due to the unknown composition of carbonate and/or the influence of particle size and shape on sinking rates. It also remains noticeable that the highest sinking rates occurred in dust-rich ocean regions off NW Africa, but this issue deserves further detailed field and laboratory investigations. We obtained increasing sinking rates with depth. By using a seven-compartment biogeochemical model, it was shown that the deep ocean organic carbon flux at a mesotrophic sediment trap site off Cape Blanc can be captured fairly well using seasonal variable particle sinking rates. Our model provides a total organic carbon flux of 0.29 Tg per year down to 3000 m off the NW African upwelling

Oxygen permeation flux through La1-ySryFeO3 limited by the carbon monoxide oxidation rate

NARCIS (Netherlands)

van Hassel, B.A.; van Hassel, B.A.; ten Elshof, Johan E.; Bouwmeester, Henricus J.M.

1995-01-01

The oxygen permeation flux through La1-ySryFeO3-δ (y = 0.1, 0.2) in a large oxygen partial pressure gradient (air/CO, CO2 mixture) was found to be limited by the carbon monoxide oxidation rate at the low oxygen partial pressure side of the membrane. The oxygen permeation flux through the membrane

Influence of internal and external boundary conditions on the decrement factor and time lag heat flux of building walls in steady periodic regime

International Nuclear Information System (INIS)

Mazzeo, D.; Oliveti, G.; Arcuri, N.

2016-01-01

Highlights: • Dynamic behaviour of building walls subjected to sinusoidal and actual loadings. • The joint action of more temperature and heat flux loadings has been considered. • Dynamic parameters were defined by the internal and external fluctuating heat flux. • Use of the Total Harmonic Distortion to determine the number of harmonics required. • Study of the influence of external and internal loadings on dynamic parameters. - Abstract: The dynamic behaviour of opaque components of the building envelope in steady periodic regime is investigated using parameters defined by the fluctuating heat flux that is transferred in the wall. The use of the heat flux allows for the joint action of the loadings that characterise both the outdoor environment and the indoor air-conditioned environment to be taken into account. The analysis was developed in sinusoidal conditions to determine the frequency response of the wall and in non-sinusoidal conditions to identify the actual dynamic behaviour of the wall. The use of non-dimensional periodic thermal transmittance is proposed for the sinusoidal analysis in order to evaluate the decrement factor and the time lag that the heat flux undergoes in crossing the wall as well as the efficiency of heat storage. In the presence of non-sinusoidal loadings, the identification of the dynamic behaviour of the wall is obtained using several dynamic parameters: the decrement factor in terms of energy, defined as the ratio between the energy in a semi-period entering and exiting the wall; the decrement factor and the time lag in terms of heat flux, considering the maximum peak and the minimum peak. These parameters allow for the identification of how the form of the heat flux trend crossing the wall is modified. The number of harmonics to be considered for an accurate representation of heat fluxes is determined by means of the introduction of the Total Harmonic Distortion (THD), which quantifies the distortion of a non

A new disjunct eddy-covariance system for BVOC flux measurements - validation on CO2 and H2O fluxes

Science.gov (United States)

Baghi, R.; Durand, P.; Jambert, C.; Jarnot, C.; Delon, C.; Serça, D.; Striebig, N.; Ferlicoq, M.; Keravec, P.

2012-12-01

The disjunct eddy covariance (DEC) method is an interesting alternative to the conventional eddy covariance (EC) method because it allows the estimation of turbulent fluxes of species for which fast sensors are not available. We have developed and validated a new disjunct sampling system (called MEDEE). This system is built with chemically inert materials. Air samples are taken quickly and alternately in two cylindrical reservoirs, the internal pressures of which are regulated by a moving piston. The MEDEE system was designed to be operated either on the ground or aboard an aircraft. It is also compatible with most analysers since it transfers the air samples at a regulated pressure. To validate the system, DEC and EC measurements of CO2 and latent heat fluxes were performed concurrently during a field campaign. EC fluxes were first compared to simulated DEC (SDEC) fluxes and then to actual DEC fluxes. Both the simulated and actual DEC fluxes showed a good agreement with EC fluxes in terms of correlation. The determination coefficients (R2) were 0.93 and 0.91 for DEC and SDEC latent heat fluxes, respectively. For DEC and SDEC CO2 fluxes R2 was 0.69 in both cases. The conditions of low fluxes experienced during the campaign impaired the comparison of the different techniques especially for CO2 flux measurements. Linear regression analysis showed an 14% underestimation of DEC fluxes for both CO2 and latent heat compared to EC fluxes. A first field campaign, focusing on biogenic volatile organic compound (BVOC) emissions, was carried out to measure isoprene fluxes above a downy oak (Quercus Pubescens) forest in the south-east of France. The measured standard emission rate was in the lower range of reported values in earlier studies. Further analysis will be conducted through ground-based and airborne campaigns in the coming years.

Exchange Rate Effects on International Commercial Trade Competitiveness

Directory of Open Access Journals (Sweden)

Ionel Bostan

2018-04-01

Full Text Available This study is meant to be an evaluation sustained by theoretical and empirical considerations of the exchange rate impact on international commercial trade competitiveness. In this respect, the study aims to find how the exchange rate influences Romanian competitiveness through assessing the effects generated on exports and imports. The main purpose of the study is to assess the complex action of the exchange rate on international commercial trade competitiveness in contemporaneity and the connections between these variables. The empirical part contains a regression analysis where exports and imports are dependent variables influenced by a series of determinants.

Temperature and heat flux scaling laws for isoviscous, infinite Prandtl number mixed heating convection.

Science.gov (United States)

Vilella, Kenny; Deschamps, Frederic

2018-04-01

Thermal evolution of terrestrial planets is controlled by heat transfer through their silicate mantles. A suitable framework for modelling this heat transport is a system including bottom heating (from the core) and internal heating, e.g., generated by secular cooling or by the decay of radioactive isotopes. The mechanism of heat transfer depends on the physical properties of the system. In systems where convection is able to operate, two different regimes are possible depending on the relative amount of bottom and internal heating. For moderate internal heating rates, the system is composed of active hot upwellings and cold downwellings. For large internal heating rates, the bottom heat flux becomes negative and the system is only composed of active cold downwellings. Here, we build theoretical scaling laws for both convective regimes following the approach of Vilella & Kaminski (2017), which links the surface heat flux and the temperature jump across both the top and bottom thermal boundary layer (TBL) to the Rayleigh number and the dimensionless internal heating rate. Theoretical predictions are then verified against numerical simulations performed in 2D and 3D-Cartesian geometry, and covering a large range of the parameter space. Our theoretical scaling laws are more successful in predicting the thermal structure of systems with large internal heating rates than that of systems with no or moderate internal heating. The differences between moderate and large internal heating rates are interpreted as differences in the mechanisms generating thermal instabilities. We identified three mechanisms: conductive growth of the TBL, instability impacting, and TBL erosion, the last two being present only for moderate internal heating rates, in which hot plumes are generated at the bottom of the system and are able to reach the surface. Finally, we apply our scaling laws to the evolution of the early Earth, proposing a new model for the cooling of the primordial magma ocean

Critical heat flux analysis on change of plate temperature and cooling water flow rate for rectangular narrow gap with bilateral-heated cases

International Nuclear Information System (INIS)

M Hadi Kusuma; Mulya Juarsa; Anhar Riza Antariksawan

2013-01-01

Boiling heat transfer phenomena on rectangular narrow gap was related to the safety of nuclear reactors. Research done in order to study the safety of nuclear reactors in particular relating to boiling heat transfer and useful on the improvement of next-generation reactor designs. The research focused on calculation of the heat flux during the cooling process in rectangular narrow gap size 1.0 mm. with initial temperatures 200°C. 400°C, and 600°C, also the flow rates of cooling water 0,1 liters/second. 0,2 liters/second. and 0,3 liters/second. Experiments carried out by injecting water at a certain flow rate with the water temperature 85°C. Transient temperature measurement data recorded by the data acquisition system. Transient temperature measurement data is used to calculate the flux of heat gain is then used to obtain the heat transfer coefficient. This research aimed to obtain the correlation between critical heat flux and heat transfer coefficient to changes in temperatures and water flow rates for bilaterally-heated cases on rectangular narrow gap. The results obtained for a constant cooling water flow rate, critical heat flux will increase when hot plate temperature also increased. While on a constant hot plate temperature, coefficient heat transfer will increase when cooling water flow rate also increased. Thus it can be said that the cooling water flow rate and temperature of the hot plate has a significant effect on the critical heat flux and heat transfer coefficient resulted in quenching process of vertical rectangular narrow gap with double-heated cases. (author)

Wintertime Air-Sea Gas Transfer Rates and Air Injection Fluxes at Station Papa in the NE Pacific

Science.gov (United States)

McNeil, C.; Steiner, N.; Vagle, S.

2008-12-01

In recent studies of air-sea fluxes of N2 and O2 in hurricanes, McNeil and D'Asaro (2007) used a simplified model formulation of air-sea gas flux to estimate simultaneous values of gas transfer rate, KT, and air injection flux, VT. The model assumes air-sea gas fluxes at high to extreme wind speeds can be explained by a combination of two processes: 1) air injection, by complete dissolution of small bubbles drawn down into the ocean boundary layer by turbulent currents, and 2) near-surface equilibration processes, such as occurs within whitecaps. This analysis technique relies on air-sea gas flux estimates for two gases, N2 and O2, to solve for the two model parameters, KT and VT. We present preliminary results of similar analysis of time series data collected during winter storms at Station Papa in the NE Pacific during 2003/2004. The data show a clear increase in KT and VT with increasing NCEP derived wind speeds and acoustically measured bubble penetration depth.

Flux flow and flux creep in thick films of YBCO. [Y-Ba-Cu-O

Energy Technology Data Exchange (ETDEWEB)

Rickets, J.; Vinen, W.F.; Abell, J.S.; Shields, T.C. (Superconductivity Research Group, Univ. of Birmingham (United Kingdom))

1991-12-01

The results are described of new experiments designed to study flux creep and flux flow along a single flux percolation path in thick films of YBCO. The flux flow regime is studied by a four-point resistive technique using pulsed currents, and the flux creep regime by observing the rate at which flux enters a superconducting loop in parallel with the resistance that is associated with the flux percolation path. (orig.).

Neutron and Gamma Fluxes and dpa Rates for HFIR Vessel Beltline Region (Present and Upgrade Designs)

Energy Technology Data Exchange (ETDEWEB)

Blakeman, E.D.

2001-01-11

The Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR) is currently undergoing an upgrading program, a part of which is to increase the diameters of two of the four radiation beam tubes (HB-2 and HB-4). This change will cause increased neutron and gamma radiation dose rates at and near locations where the tubes penetrate the vessel wall. Consequently, the rate of radiation damage to the reactor vessel wall at those locations will also increase. This report summarizes calculations of the neutron and gamma flux (particles/cm{sup 2}/s) and the dpa rate (displacements/atom/s) in iron at critical locations in the vessel wall. The calculated dpa rate values have been recently incorporated into statistical damage evaluation codes used in the assessment of radiation induced embrittlement. Calculations were performed using models based on the discrete ordinates methodology and utilizing ORNL two-dimensional and three-dimensional discrete ordinates codes. Models for present and proposed beam tube designs are shown and their results are compared. Results show that for HB-2, the dpa rate in the vessel wall where the tube penetrates the vessel will be increased by {approximately}10 by the proposed enlargement. For HB-4, a smaller increase of {approximately}2.6 is calculated.

The Effect of Cumulus Cloud Field Anisotropy on Domain-Averaged Solar Fluxes and Atmospheric Heating Rates

Science.gov (United States)

Hinkelman, Laura M.; Evans, K. Franklin; Clothiaux, Eugene E.; Ackerman, Thomas P.; Stackhouse, Paul W., Jr.

2006-01-01

Cumulus clouds can become tilted or elongated in the presence of wind shear. Nevertheless, most studies of the interaction of cumulus clouds and radiation have assumed these clouds to be isotropic. This paper describes an investigation of the effect of fair-weather cumulus cloud field anisotropy on domain-averaged solar fluxes and atmospheric heating rate profiles. A stochastic field generation algorithm was used to produce twenty three-dimensional liquid water content fields based on the statistical properties of cloud scenes from a large eddy simulation. Progressively greater degrees of x-z plane tilting and horizontal stretching were imposed on each of these scenes, so that an ensemble of scenes was produced for each level of distortion. The resulting scenes were used as input to a three-dimensional Monte Carlo radiative transfer model. Domain-average transmission, reflection, and absorption of broadband solar radiation were computed for each scene along with the average heating rate profile. Both tilt and horizontal stretching were found to significantly affect calculated fluxes, with the amount and sign of flux differences depending strongly on sun position relative to cloud distortion geometry. The mechanisms by which anisotropy interacts with solar fluxes were investigated by comparisons to independent pixel approximation and tilted independent pixel approximation computations for the same scenes. Cumulus anisotropy was found to most strongly impact solar radiative transfer by changing the effective cloud fraction, i.e., the cloud fraction when the field is projected on a surface perpendicular to the direction of the incident solar beam.

ANALYSIS OF MEASURES FOR INCREASING THE RATING OF UNIVERSITY IN INTERNATIONAL RATING SYSTEM

Directory of Open Access Journals (Sweden)

В.П. Харченко

2011-02-01

Full Text Available The principles of forming the world's most popular international Internet-ranking of universities are considered. The principles of forming the international rating of electronic resources known as Webometrics, which results are defined by summing four values based on quantity of unique external links to the site page and by the quantity of “valuable” files placed on website are represented.  Мost Internet ratings make slope on the  Web activity of the university and its researchers, therefore the participation of entire staff at university is required

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

Cross-correlations between RMB exchange rate and international commodity markets

Science.gov (United States)

Lu, Xinsheng; Li, Jianfeng; Zhou, Ying; Qian, Yubo

2017-11-01

This paper employs multifractal detrended analysis (MF-DFA) and multifractal detrended cross-correlation analysis (MF-DCCA) to study cross-correlation behaviors between China's RMB exchange rate market and four international commodity markets, using a comprehensive set of data covering the period from 22 July 2005 to 15 March 2016. Our empirical results from MF-DFA indicate that the RMB exchange rate is the most inefficient among the 4 selected markets. The results from quantitative analysis have testified the existence of cross-correlations and the result from MF-DCCA have further confirmed a strong multifractal behavior between RMB exchange rate and international commodity markets. We also demonstrate that the recent financial crisis has significant impact on the cross-correlated behavior. Through the rolling window analysis, we find that the RMB exchange rates and international commodity prices are anti-persistent cross-correlated. The main sources of multifractality in the cross-correlations are long-range correlations between RMB exchange rate and the aggregate commodity, energy and metals index.

Organic carbon mass accumulation rate regulates the flux of reduced substances from the sediments of deep lakes

Directory of Open Access Journals (Sweden)

T. Steinsberger

2017-07-01

Full Text Available The flux of reduced substances, such as methane and ammonium, from the sediment to the bottom water (Fred is one of the major factors contributing to the consumption of oxygen in the hypolimnia of lakes and thus crucial for lake oxygen management. This study presents fluxes based on sediment porewater measurements from different water depths of five deep lakes of differing trophic states. In meso- to eutrophic lakes Fred was directly proportional to the total organic carbon mass accumulation rate (TOC-MAR of the sediments. TOC-MAR and thus Fred in eutrophic lakes decreased systematically with increasing mean hypolimnion depth (zH, suggesting that high oxygen concentrations in the deep waters of lakes were essential for the extent of organic matter mineralization leaving a smaller fraction for anaerobic degradation and thus formation of reduced compounds. Consequently, Fred was low in the 310 m deep meso-eutrophic Lake Geneva, with high O2 concentrations in the hypolimnion. By contrast, seasonal anoxic conditions enhanced Fred in the deep basin of oligotrophic Lake Aegeri. As TOC-MAR and zH are based on more readily available data, these relationships allow estimating the areal O2 consumption rate by reduced compounds from the sediments where no direct flux measurements are available.

76 FR 65639 - International Mail: Proposed Product Rate and Fee Changes

Science.gov (United States)

2011-10-24

... Customs Clearance and Delivery Fee International Reply Coupons International Business Reply Service The... * * * * * International Business Reply Service (382) [For each country that offers International Business Reply Service... POSTAL SERVICE 39 CFR Part 20 International Mail: Proposed Product Rate and Fee Changes AGENCY...

About Merging Threshold and Critical Flux Concepts into a Single One: The Boundary Flux

Directory of Open Access Journals (Sweden)

Marco Stoller

2014-01-01

Full Text Available In the last decades much effort was put in understanding fouling phenomena on membranes. One successful approach to describe fouling issues on membranes is the critical flux theory. The possibility to measure a maximum value of the permeate flux for a given system without incurring in fouling issues was a breakthrough in membrane process design. However, in many cases critical fluxes were found to be very low, lower than the economic feasibility of the process. The knowledge of the critical flux value must be therefore considered as a good starting point for process design. In the last years, a new concept was introduced, the threshold flux, which defines the maximum permeate flow rate characterized by a low constant fouling rate regime. This concept, more than the critical flux, is a new practical tool for membrane process designers. In this paper a brief review on critical and threshold flux will be reported and analyzed. And since the concepts share many common aspects, merged into a new concept, called the boundary flux, the validation will occur by the analysis of previously collected data by the authors, during the treatment of olive vegetation wastewater by ultrafiltration and nanofiltration membranes.

Poloidal flux requirement: Analysis and application to the Ignitor configuration

International Nuclear Information System (INIS)

Nassi, M.

1993-01-01

The definitions and correlations existing between different terms used by physicists and engineers are clarified in order to deal with the assessment of the poloidal flux requirement in a fusion experiment. The theoretical formulation of both the Faraday and the Poynting methods, for the internal flux evaluation, is briefly reviewed. Heuristic expressions that allow estimates of internal flux consumption are reported for the specific case of an ignition experiment represented by the Ignitor configuration. The analytical and heuristic results for both internal and external poloidal flux requirements are checked against numerical evaluations carried out by using the TSC transport and magnetohydrodynamics code and the TEQ equilibrium code. A fairly good agreement between the different estimates is found. This suggests that simple heuristic expressions can be used to evaluate the poloidal flux requirement of future experiments, even if a detailed simulation of the plasma current penetration process is strongly recommended to correctly assess and optimize the resistive poloidal flux consumption. Finally, the poloidal flux requirement for different plasma scenarios in the Ignitor experiment is compared with the magnetic flux variation that can be delivered by the poloidal field system. 28 refs., 4 figs., 10 tabs

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.

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.

INTERNATIONAL RATINGS IN DETERMINING THE FINANCIAL STABILITY OF UKRAINE

Directory of Open Access Journals (Sweden)

N. Plieshakova

2014-01-01

Full Text Available Problem of the global financial stability and position of Ukraine in international ratings are considered in the paper. Impact of ratings assessment on the financial stability of the country in general is analysed.

A punctual flux estimator and reactions rates optimization in neutral particles transport calculus by the Monte Carlo method

International Nuclear Information System (INIS)

Authier, N.

1998-12-01

One of the questions asked in radiation shielding problems is the estimation of the radiation level in particular to determine accessibility of working persons in controlled area (nuclear power plants, nuclear fuel reprocessing plants) or to study the dose gradients encountered in material (iron nuclear vessel, medical therapy, electronics in satellite). The flux and reaction rate estimators used in Monte Carlo codes give average values in volumes or on surfaces of the geometrical description of the system. But in certain configurations, the knowledge of punctual deposited energy and dose estimates are necessary. The Monte Carlo estimate of the flux at a point of interest is a calculus which presents an unbounded variance. The central limit theorem cannot be applied thus no easy confidence level may be calculated. The convergence rate is then very poor. We propose in this study a new solution for the photon flux at a point estimator. The method is based on the 'once more collided flux estimator' developed earlier for neutron calculations. It solves the problem of the unbounded variance and do not add any bias to the estimation. We show however that our new sampling schemes specially developed to treat the anisotropy of the photon coherent scattering is necessary for a good and regular behavior of the estimator. This developments integrated in the TRIPOLI-4 Monte Carlo code add the possibility of an unbiased punctual estimate on media interfaces. (author)

The variation of methane flux rates from boreal tree species at the beginning of the growing season

Science.gov (United States)

Haikarainen, Iikka; Halmeenmäki, Elisa; Machacova, Katerina; Pihlatie, Mari

2016-04-01

Boreal forests are considered as net sink for atmospheric methane (CH4) because of the CH4 oxidizing bacteria in the aerobic soil layer. However, within the last decades it has become more evident that trees play an important role in the global CH4 budget by offering pathways for anaerobically produced CH4 from deeper soil layers to the atmosphere. Furthermore, trees may also act as independent sources of CH4. To confirm magnitude, variability and the origin of the tree mediated CH4 emissions more research is needed, especially in boreal forests which have been in a minority in such investigation. We measured tree stem and shoot CH4 exchange of three boreal tree species at the beginning of the growing season (13.4.-13.6.2015) at SMEAR II station in Hyytiälä, located in southern Finland (61° 51'N, 24° 17'E, 181 asl). The fluxes were measured from silver birch (Betula pendula), downy birch (B. pubescens) and Norway spruce (Picea abies) on two sites with differing soil type and characteristics (paludified and mineral soil), vegetation and forest structure by using the static chamber technique. Scaffold towers were used for measurements at multiple stem heights and shoots. The aim was to study the vertical profile of CH4 fluxes at stem and shoot level and compare these fluxes among the studied species, and to observe temporal changes in CH4 flux over the beginning of the growing season. We found that all the trees emitted CH4 from their stems and shoots. Overall, the birches showed higher emissions compared to the spruces. The emission rates were considerably larger in the lower parts of the birch stems than upper parts, and these emissions increased during the growing season. The spruces had more variation in the stem CH4 flux, but the emission rates of the upper parts of the stem exceeded the birch emissions at the same height. The shoot fluxes of all the studied trees indicated variable CH4 emissions without a clear pattern regarding the vertical profile and

The Influence of International Parity on the Exchange Rate: Purchasing Power Parity and International Fisher Effect

Directory of Open Access Journals (Sweden)

Oana Mionel

2012-02-01

Full Text Available This article assesses the impact of the inflationand interest rates on the exchange rates.The analysis tests the relation between the inflation rate and the exchange rate by applying thePurchasing Power Parity Theory, while the relationbetween the interest rate and the inflation rate istested by applying the International Fisher EffectTheory. In order to test the Purchasing Power Paritythe study takes into account the period of time between 1990 – 2009, and the following countries –the USA, Germany, the UK, Switzerland, Canada, Japan and China. As for testing the InternationalFisher Effect Theory the period of time is the same, 1990 – 2009, but a few countries are different –the USA, Germany, the UK, Switzerland, Canada, Australia and New Zeeland. Thus, both theoriesanalyse the USA as home country.

Extraction of the atmospheric neutrino fluxes from experimental event rate data

NARCIS (Netherlands)

Gonzalez-Garcia, M. C.; Maltoni, M.; Rojo, J.

2007-01-01

The precise knowledge of the atmospheric neutrino fluxes is a key ingredient in the interpretation of the results from any atmospheric neutrino experiment. In the standard atmospheric neutrino data analysis, these fluxes are theoretical inputs obtained from sophisticated numerical calculations. In

Continuous monitoring of fluid flow rate and contemporaneous biogeochemical fluxes in the sub-seafloor; the Mosquito flux meter

Science.gov (United States)

Culling, D. P.; Solomon, E. A.; Kastner, M.; Berg, R. D.

2013-12-01

Fluid flow through marine sediments and oceanic crust impacts seawater chemistry as well as diagenetic, thermal, seismic, and magmatic processes at plate boundaries, creates ore and gas hydrate deposits at and below seafloor, and establishes and maintains deep microbial ecosystems. However, steady-state fluid flow rates, as well as the temporal and spatial variability of fluid flow and composition are poorly constrained in many marine environments. A new, low-cost instrument deployable by ROV or submersible, named the Mosquito, was recently developed to provide continuous, long-term and campaign style monitoring of fluid flow rate and contemporaneous solute fluxes at multiple depths below the sea floor. The Mosquito consists of a frame that houses several osmotic pumps (Osmo-Samplers [OS]) connected to coils of tubing that terminate with an attachment to long thin titanium (Ti) needles, all of which are mounted to a release plate. The OS's consist of an acrylic housing which contains a brine chamber (BC) and a distilled water chamber (DWC) separated by semi permeable membranes. The osmotic gradient between the chambers drives the flow of distilled water into the BC. The DWC is connected to the Teflon tubing coil and a Ti needle, both of which are also filled with distilled water, thus the OS pulls fluid from the base of the needle through the tubing coil. One central Ti needle is attached to a custom-made tracer injection assembly, filled with a known volume of tracer, which is triggered, injecting a point source in the sediment. On a typical Mosquito, 4 needles are mounted vertically at varying depths with respect to the tracer injection needle, and 4 needles are mounted at equal depth but set at variable horizontal distances away from the tracer injection. Once the Mosquito has been placed on the seafloor, the release plate is manually triggered pushing the Ti needles into the sediment, then the tracer injection assembly is actuated. As the tracer is advected

Rates of insulin secretion in INS-1 cells are enhanced by coupling to anaplerosis and Kreb's cycle flux independent of ATP synthesis.

Science.gov (United States)

Cline, Gary W; Pongratz, Rebecca L; Zhao, Xiaojian; Papas, Klearchos K

2011-11-11

Mechanistic models of glucose stimulated insulin secretion (GSIS) established in minimal media in vitro, may not accurately describe the complexity of coupling metabolism with insulin secretion that occurs in vivo. As a first approximation, we have evaluated metabolic pathways in a typical growth media, DMEM as a surrogate in vivo medium, for comparison to metabolic fluxes observed under the typical experimental conditions using the simple salt-buffer of KRB. Changes in metabolism in response to glucose and amino acids and coupling to insulin secretion were measured in INS-1 832/13 cells. Media effects on mitochondrial function and the coupling efficiency of oxidative phosphorylation were determined by fluorometrically measured oxygen consumption rates (OCRs) combined with (31)P NMR measured rates of ATP synthesis. Substrate preferences and pathways into the TCA cycle, and the synthesis of mitochondrial 2nd messengers by anaplerosis were determined by (13)C NMR isotopomer analysis of the fate of [U-(13)C] glucose metabolism. Despite similar incremental increases in insulin secretion, the changes of OCR in response to increasing glucose from 2.5 to 15mM were blunted in DMEM relative to KRB. Basal and stimulated rates of insulin secretion rates were consistently higher in DMEM, while ATP synthesis rates were identical in both DMEM and KRB, suggesting greater mitochondrial uncoupling in DMEM. The relative rates of anaplerosis, and hence synthesis and export of 2nd messengers from the mitochondria were found to be similar in DMEM to those in KRB. And, the correlation of total PC flux with insulin secretion rates in DMEM was found to be congruous with the correlation in KRB. Together, these results suggest that signaling mechanisms associated with both TCA cycle flux and with anaplerotic flux, but not ATP production, may be responsible for the enhanced rates of insulin secretion in more complex, and physiologically-relevant media. Copyright © 2011 Elsevier Inc. All

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

Rate of Homologous Desensitization and Internalization of the GLP-1 Receptor.

Science.gov (United States)

Shaaban, Ghina; Oriowo, Mabayoje; Al-Sabah, Suleiman

2016-12-26

The glucagon-like peptide-1 receptor (GLP-1R) is an important target in the treatment of type 2 diabetes mellitus. The aim of this study was to compare the rate of agonist stimulated desensitization and internalization of GLP-1R. To this end, an N-terminally myc-tagged GLP-1R was stably expressed in HEK-293 cells. Homologous desensitization was assessed by measuring the cAMP response to agonist stimulation following pre-incubation with agonist for up to 120 min. Receptor internalization was monitored using an indirect ELISA-based method and confocal microscopy. Pre-incubation with GLP-1 resulted in a time-dependent loss of response to a second stimulation. Washing cells following pre-incubation failed to bring cAMP levels back to basal. Taking this into account, two desensitization rates were calculated: "apparent" (t 1/2 = 19.27 min) and "net" (t 1/2 = 2.99 min). Incubation of cells with GLP-1 also resulted in a time-dependent loss of receptor cell surface expression (t 1/2 = 2.05 min). Rapid agonist-stimulated internalization of GLP-1R was confirmed using confocal microscopy. Stimulation of GLP-1R with GLP-1 results in rapid desensitization and internalization of the receptor. Interestingly, the rate of "net" desensitization closely matches the rate of internalization. Our results suggest that agonist-bound GLP-1R continues to generate cAMP after it has been internalized.

Technical characterization of dialysis fluid flow and mass transfer rate in dialyzers with various filtration coefficients using dimensionless correlation equation.

Science.gov (United States)

Fukuda, Makoto; Yoshimura, Kengo; Namekawa, Koki; Sakai, Kiyotaka

2017-06-01

The objective of the present study is to evaluate the effect of filtration coefficient and internal filtration on dialysis fluid flow and mass transfer coefficient in dialyzers using dimensionless mass transfer correlation equations. Aqueous solution of vitamin B 12 clearances were obtained for REXEED-15L as a low flux dialyzer, and APS-15EA and APS-15UA as high flux dialyzers. All the other design specifications were identical for these dialyzers except for filtration coefficient. The overall mass transfer coefficient was calculated, moreover, the exponents of Reynolds number (Re) and film mass transfer coefficient of the dialysis-side fluid (k D ) for each flow rate were derived from the Wilson plot and dimensionless correlation equation. The exponents of Re were 0.4 for the low flux dialyzer whereas 0.5 for the high flux dialyzers. Dialysis fluid of the low flux dialyzer was close to laminar flow because of its low filtration coefficient. On the other hand, dialysis fluid of the high flux dialyzers was assumed to be orthogonal flow. Higher filtration coefficient was associated with higher k D influenced by mass transfer rate through diffusion and internal filtration. Higher filtration coefficient of dialyzers and internal filtration affect orthogonal flow of dialysis fluid.

Manipulating the discount rate when valuing international investment projects

Directory of Open Access Journals (Sweden)

A. A. Medved

2017-01-01

Full Text Available The article deals with the practice of evaluation of international investment projects using the cash flow discounting rate. The problem of the discount rate manipulating is connected with the category “country risk”, which often determines the impact on the rate and, accordingly, the investment decisions. Critically examines existing approaches to the definition of “country risk”. Categories that make up a complete picture of “country risk” are distinguished. The general defect of existing country risk concepts is revealed – the fact that the measurements are based on rather subjective assessments and do not have sufficient empirical evidence, the fact that almost all of them have a clear liberal democratic bias: as a rule, drawing attention to the relationship between the political system and stability, the liberal democratic structure of society is recognized as the most stable, without any acceptable scientific evidence, followed by autocracy, military dictatorships and new independent states. The author affirms the lack of a clear and unambiguous definition of this category, the controversial approach to ranking of countries. The author analyzes and proves the bias of rating assigned by foreign companies. As a conclusion the need to create a national research concept of the “country risk” category is аffirms with the subsequent promotion of national rating agencies to the world market. The author's conception of the category “country risk” is proposed, an author's definition is given to this notion, it is recommended to establish the primacy of national ratings over foreign ones both in domestic and international relations in order to have independent influence on international capital flows. It is also proposed the evaluation of projects based on the dynamic discounting rates, especially for long-term strategic projects.

Are international fund flows related to exchange rate dynamics?

NARCIS (Netherlands)

Li, Suxiao; de Haan, Jakob; Scholtens, Bert

2018-01-01

Employing monthly data for 53 countries between 1996 and 2015, we investigate the relationship between international fund flows and exchange rate dynamics. We find strong co-movement between funds flows (as measured with the EPFR Global data base) and bilateral real exchange rates vis-à-vis the USD.

The role of metabolism in modulating CO2 fluxes in boreal lakes

Science.gov (United States)

Bogard, Matthew J.; del Giorgio, Paul A.

2016-10-01

Lake CO2 emissions are increasingly recognized as an important component of the global CO2 cycle, yet the origin of these emissions is not clear, as specific contributions from metabolism and in-lake cycling, versus external inputs, are not well defined. To assess the coupling of lake metabolism with CO2 concentrations and fluxes, we estimated steady state ratios of gross primary production to respiration (GPP:R) and rates of net ecosystem production (NEP = GPP-R) from surface water O2 dynamics (concentration and stable isotopes) in 187 boreal lakes spanning long environmental gradients. Our findings suggest that internal metabolism plays a dominant role in regulating CO2 fluxes in most lakes, but this pattern only emerges when examined at a resolution that accounts for the vastly differing relationships between lake metabolism and CO2 fluxes. Fluxes of CO2 exceeded those from NEP in over half the lakes, but unexpectedly, these effects were most common and typically largest in a subset ( 30% of total) of net autotrophic lakes that nevertheless emitted CO2. Equally surprising, we found no environmental characteristics that distinguished this category from the more common net heterotrophic, CO2 outgassing lakes. Excess CO2 fluxes relative to NEP were best predicted by catchment structure and hydrologic properties, and we infer from a combination of methods that both catchment inputs and internal anaerobic processes may have contributed this excess CO2. Together, our findings show that the link between lake metabolism and CO2 fluxes is often strong but can vary widely across the boreal biome, having important implications for catchment-wide C budgets.

Forward flux sampling calculation of homogeneous nucleation rates from aqueous NaCl solutions.

Science.gov (United States)

Jiang, Hao; Haji-Akbari, Amir; Debenedetti, Pablo G; Panagiotopoulos, Athanassios Z

2018-01-28

We used molecular dynamics simulations and the path sampling technique known as forward flux sampling to study homogeneous nucleation of NaCl crystals from supersaturated aqueous solutions at 298 K and 1 bar. Nucleation rates were obtained for a range of salt concentrations for the Joung-Cheatham NaCl force field combined with the Extended Simple Point Charge (SPC/E) water model. The calculated nucleation rates are significantly lower than the available experimental measurements. The estimates for the nucleation rates in this work do not rely on classical nucleation theory, but the pathways observed in the simulations suggest that the nucleation process is better described by classical nucleation theory than an alternative interpretation based on Ostwald's step rule, in contrast to some prior simulations of related models. In addition to the size of NaCl nucleus, we find that the crystallinity of a nascent cluster plays an important role in the nucleation process. Nuclei with high crystallinity were found to have higher growth probability and longer lifetimes, possibly because they are less exposed to hydration water.

Is X-ray emissivity constant on magnetic flux surfaces?

International Nuclear Information System (INIS)

Granetz, R.S.; Borras, M.C.

1997-01-01

Knowledge of the elongations and shifts of internal magnetic flux surfaces can be used to determine the q profile in elongated tokamak plasmas. X-ray tomography is thought to be a reasonable technique for independently measuring internal flux surface shapes, because it is widely believed that X-ray emissivity should be constant on a magnetic flux surface. In the Alcator C-Mod tokamak, the X-ray tomography diagnostic system consists of four arrays of 38 chords each. A comparison of reconstructed X-ray contours with magnetic flux surfaces shows a small but consistent discrepancy in the radial profile of elongation. Numerous computational tests have been performed to verify these findings, including tests of the sensitivity to calibration and viewing geometry errors, the accuracy of the tomography reconstruction algorithms, and other subtler effects. We conclude that the discrepancy between the X-ray contours and the magnetic flux surfaces is real, leading to the conclusion that X-ray emissivity is not exactly constant on a flux surface. (orig.)

The Effect of Growth Temperature and V/III Flux Ratio of MOCVD Antimony Based Semiconductors on Growth Rate and Surface Morphology

Directory of Open Access Journals (Sweden)

Ramelan Ari Handono

2017-01-01

Full Text Available Epitaxial Alx Ga1-x Sb layers on GaSb and GaAs substrates have been grown by atmospheric pressure metalorganic chemical vapor deposition using TMAl, TMGa and TMSb. Nomarski microscope and a profiler were employed to examine the surface morphology and growth rate of the samples. We report the effect of growth temperature and V/III flux ratio on growth rate and surface morphology. Growth temperatures in the range of 520°C and 680°C and V/III ratios from 1 to 5 have been investigated. A growth rate activation energy of 0.73 eV was found. At low growth temperatures between 520 and 540°C, the surface morphology is poor due to antimonide precipitates associated with incomplete decomposition of the TMSb. For layers grown on GaAs at 580°C and 600°C with a V/III ratio of 3 a high quality surface morphology is typical, with a mirror-like surface and good composition control. It was found that a suitable growth temperature and V/III flux ratio was beneficial for producing good AlGaSb layers. Undoped AlGaSb grown at 580°C with a V/III flux ratio of 3 at the rate of 3.5 μm/hour shows p-type conductivity with smooth surface morphology

Relationship between internal medicine program board examination pass rates, accreditation standards, and program size.

Science.gov (United States)

Falcone, John L; Gonzalo, Jed D

2014-01-19

To determine Internal Medicine residency program compliance with the Accreditation Council for Graduate Medical Education 80% pass-rate standard and the correlation between residency program size and performance on the American Board of Internal Medicine Certifying Examination. Using a cross-sectional study design from 2010-2012 American Board of Internal Medicine Certifying Examination data of all Internal Medicine residency pro-grams, comparisons were made between program pass rates to the Accreditation Council for Graduate Medical Education pass-rate standard. To assess the correlation between program size and performance, a Spearman's rho was calculated. To evaluate program size and its relationship to the pass-rate standard, receiver operative characteristic curves were calculated. Of 372 Internal Medicine residency programs, 276 programs (74%) achieved a pass rate of =80%, surpassing the Accreditation Council for Graduate Medical Education minimum standard. A weak correlation was found between residency program size and pass rate for the three-year period (p=0.19, pInternal Medicine residency programs complied with Accreditation Council for Graduate Medical Education pass-rate standards, a quarter of the programs failed to meet this requirement. Program size is positively but weakly associated with American Board of Internal Medicine Certifying Examination performance, suggesting other unidentified variables significantly contribute to program performance.

Exchange Rate and International Trade: Case From Indonesian Manufacturing Sector

Directory of Open Access Journals (Sweden)

Anung Yoga Anindhita

2017-07-01

Full Text Available Exchange rate fluctuation in Floating Exchange Rate Regime is considered to Exchange rate fluctuation in Floating Exchange Rate Regime is considered to have impacts on the international trade through its adjustment to the price and its volatility to the trade risk. This paper is aimed at estimating those impacts on the international trade of manufacturing sector in Indonesia for period 2007 to 2014. To conduct estimation, it uses multiple regression analysis on two models: First, the import of raw-and-auxiliary materials; Second, the export of manufacturing sector. The results show that the exchange rate impacts both work significantly on the import of raw-and-auxiliary materials. The finding implies that, through the import of raw-and-auxiliary materials, manufacturing sector is very susceptible to the shock caused by exchange rate changes. Meanwhile, the export of manufacturing sector is not able to take advantage of the depreciation of the exchange rate due to the lack of competitiveness.DOI: 10.15408/sjie.v6i2.5210

BRIGITTE, Dose Rate and Heat Source and Energy Flux for Self-Absorbing Rods

International Nuclear Information System (INIS)

Jegu, M.; Clement, M.

1978-01-01

1 - Nature of physical problem solved: Calculation of dose rate, heat sources or energy flux. The sources are self-absorbing radioactive rods. The shielding consists of blocks of which the cross section can be defined. 2 - Method of solution: Exponential attenuation and build-up factor between source points and detector points. Source integration with error estimate. Automatic or controlled build-up with monitor print-out. 3 - Restrictions on the complexity of the problem: Number of energy points, regions, detector points, abscissa points of the rod, vertical position of the rod, are all limited to ten. The maximum total number of vertical steps is 124

CrossRef Antiproton Flux, Antiproton-to-Proton Flux Ratio, and Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station

CERN Document Server

Aguilar, M; Alpat, B; Ambrosi, G; Arruda, L; Attig, N; Aupetit, S; Azzarello, P; Bachlechner, A; Barao, F; Barrau, A; Barrin, L; Bartoloni, A; Basara, L; Başeǧmez-du Pree, S; Battarbee, M; Battiston, R; Bazo, J; Becker, U; Behlmann, M; Beischer, B; Berdugo, J; Bertucci, B; Bindi, V; Boella, G; de Boer, W; Bollweg, K; Bonnivard, V; Borgia, B; Boschini, M  J; Bourquin, M; Bueno, E  F; Burger, J; Cadoux, F; Cai, X  D; Capell, M; Caroff, S; Casaus, J; Castellini, G; Cernuda, I; Cervelli, F; Chae, M  J; Chang, Y  H; Chen, A  I; Chen, G  M; Chen, H  S; Cheng, L; Chou, H  Y; Choumilov, E; Choutko, V; Chung, C  H; Clark, C; Clavero, R; Coignet, G; Consolandi, C; Contin, A; Corti, C; Coste, B; Creus, W; Crispoltoni, M; Cui, Z; Dai, Y  M; Delgado, C; Della Torre, S; Demirköz, M  B; Derome, L; Di Falco, S; Dimiccoli, F; Díaz, C; von Doetinchem, P; Dong, F; Donnini, F; Duranti, M; D'Urso, D; Egorov, A; Eline, A; Eronen, T; Feng, J; Fiandrini, E; Finch, E; Fisher, P; Formato, V; Galaktionov, Y; Gallucci, G; García, B; García-López, R  J; Gargiulo, C; Gast, H; Gebauer, I; Gervasi, M; Ghelfi, A; Giovacchini, F; Goglov, P; Gómez-Coral, D  M; Gong, J; Goy, C; Grabski, V; Grandi, D; Graziani, M; Guerri, I; Guo, K  H; Habiby, M; Haino, S; Han, K  C; He, Z  H; Heil, M; Hoffman, J; Hsieh, T  H; Huang, H; Huang, Z  C; Huh, C; Incagli, M; Ionica, M; Jang, W  Y; Jinchi, H; Kang, S  C; Kanishev, K; Kim, G  N; Kim, K  S; Kirn, Th; Konak, C; Kounina, O; Kounine, A; Koutsenko, V; Krafczyk, M  S; La Vacca, G; Laudi, E; Laurenti, G; Lazzizzera, I; Lebedev, A; Lee, H  T; Lee, S  C; Leluc, C; Li, H  S; Li, J  Q; Li, Q; Li, T  X; Li, W; Li, Z  H; Li, Z  Y; Lim, S; Lin, C  H; Lipari, P; Lippert, T; Liu, D; Liu, Hu; Lu, S  Q; Lu, Y  S; Luebelsmeyer, K; Luo, F; Luo, J  Z; Lv, S  S; Majka, R; Mañá, C; Marín, J; Martin, T; Martínez, G; Masi, N; Maurin, D; Menchaca-Rocha, A; Meng, Q; Mo, D  C; Morescalchi, L; Mott, P; Nelson, T; Ni, J  Q; Nikonov, N; Nozzoli, F; Nunes, P; Oliva, A; Orcinha, M; Palmonari, F; Palomares, C; Paniccia, M; Pauluzzi, M; Pensotti, S; Pereira, R; Picot-Clemente, N; Pilo, F; Pizzolotto, C; Plyaskin, V; Pohl, M; Poireau, V; Putze, A; Quadrani, L; Qi, X  M; Qin, X; Qu, Z  Y; Räihä, T; Rancoita, P  G; Rapin, D; Ricol, J  S; Rodríguez, I; Rosier-Lees, S; Rozhkov, A; Rozza, D; Sagdeev, R; Sandweiss, J; Saouter, P; Schael, S; Schmidt, S  M; Schulz von Dratzig, A; Schwering, G; Seo, E  S; Shan, B  S; Shi, J  Y; Siedenburg, T; Son, D; Song, J  W; Sun, W  H; Tacconi, M; Tang, X  W; Tang, Z  C; Tao, L; Tescaro, D; Ting, Samuel C  C; Ting, S  M; Tomassetti, N; Torsti, J; Türkoğlu, C; Urban, T; Vagelli, V; Valente, E; Vannini, C; Valtonen, E; Vázquez Acosta, M; Vecchi, M; Velasco, M; Vialle, J  P; Vitale, V; Vitillo, S; Wang, L  Q; Wang, N  H; Wang, Q  L; Wang, X; Wang, X  Q; Wang, Z  X; Wei, C  C; Weng, Z  L; Whitman, K; Wienkenhöver, J; Willenbrock, M; Wu, H; Wu, X; Xia, X; Xiong, R  Q; Xu, W; Yan, Q; Yang, J; Yang, M; Yang, Y; Yi, H; Yu, Y  J; Yu, Z  Q; Zeissler, S; Zhang, C; Zhang, J; Zhang, J  H; Zhang, S  D; Zhang, S  W; Zhang, Z; Zheng, Z  M; Zhu, Z  Q; Zhuang, H  L; Zhukov, V; Zichichi, A; Zimmermann, N; Zuccon, P

2016-01-01

A precision measurement by AMS of the antiproton flux and the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on 3.49×105 antiproton events and 2.42×109 proton events. The fluxes and flux ratios of charged elementary particles in cosmic rays are also presented. In the absolute rigidity range ∼60 to ∼500  GV, the antiproton p¯, proton p, and positron e+ fluxes are found to have nearly identical rigidity dependence and the electron e− flux exhibits a different rigidity dependence. Below 60 GV, the (p¯/p), (p¯/e+), and (p/e+) flux ratios each reaches a maximum. From ∼60 to ∼500  GV, the (p¯/p), (p¯/e+), and (p/e+) flux ratios show no rigidity dependence. These are new observations of the properties of elementary particles in the cosmos.

Comparison of the 1D flux theory with a 2D hydrodynamic secondary settling tank model.

Science.gov (United States)

Ekama, G A; Marais, P

2004-01-01

The applicability of the 1D idealized flux theory (1DFT) for design of secondary settling tanks (SSTs) is evaluated by comparing its predicted maximum surface overflow (SOR) and solids loading (SLR) rates with that calculated from the 2D hydrodynamic model SettlerCAD using as a basis 35 full scale SST stress tests conducted on different SSTs with diameters from 30 to 45m and 2.25 to 4.1 m side water depth, with and without Stamford baffles. From the simulations, a relatively consistent pattern appeared, i.e. that the 1DFT can be used for design but its predicted maximum SLR needs to be reduced by an appropriate flux rating, the magnitude of which depends mainly on SST depth and hydraulic loading rate (HLR). Simulations of the sloping bottom shallow (1.5-2.5 m SWD) Dutch SSTs tested by STOWa and the Watts et al. SST, all with doubled SWDs, and the Darvill new (4.1 m) and old (2.5 m) SSTs with interchanged depths, were run to confirm the sensitivity of the flux rating to depth and HLR. Simulations with and without a Stamford baffle were also done. While the design of the internal features of the SST, such as baffling, have a marked influence on the effluent SS concentration for underloaded SSTs, these features appeared to have only a small influence on the flux rating, i.e. capacity, of the SST, In the meantime until more information is obtained, it would appear that from the simulations so far that the flux rating of 0.80 of the 1DFT maximum SLR recommended by Ekama and Marais remains a reasonable value to apply in the design of full scale SSTs--for deep SSTs (4 m SWD) the flux rating could be increased to 0.85 and for shallow SSTs (2.5 m SWD) decreased to 0.75. It is recommended that (i) while the apparent interrelationship between SST flux rating and depth suggests some optimization of the volume of the SST, that this be avoided and that (ii) the depth of the SST be designed independently of the surface area as is usually the practice and once selected, the

Soil surface CO2 fluxes and the carbon budget of a grassland

Science.gov (United States)

Norman, J. M.; Garcia, R.; Verma, S. B.

1992-01-01

Measurements of soil surface CO2 fluxes are reported for three sites within the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) area, and simple empirical equations are fit to the data to provide predictions of soil fluxes from environmental observations. A prototype soil chamber, used to make the flux measurements, is described and tested by comparing CO2 flux measurements to a 40-L chamber, a 1-m/cu chamber, and eddy correlation. Results suggest that flux measurements with the prototype chamber are consistent with measurements by other methods to within about 20 percent. A simple empirical equation based on 10-cm soil temperature, 0- to 10-cm soil volumetric water content, and leaf area index predicts the soil surface CO2 flux with a rms error of 1.2 micro-mol sq m/s for all three sites. Further evidence supports using this equation to evaluate soil surface CO2 during the 1987 FIFE experiment. The soil surface CO2 fluxes when averaged over 24 hours are comparable to daily gross canopy photosynthetic rates. For 6 days of data the net daily accumulation of carbon is about 0.6 g CO2 sq m/d; this is only a few percent of the daily gross accumulation of carbon by photosynthesis. As the soil became drier in 1989, the net accumulation of carbon by the prairie increased, suggesting that the soil flux is more sensitive to temperature and drought than the photosynthetic fluxes.

The potential influence of multiple scattering on longwave flux and heating rate simulations with clouds

Science.gov (United States)

Kuo, C. P.; Yang, P.; Huang, X.; Feldman, D.; Flanner, M.; Kuo, C.; Mlawer, E. J.

2017-12-01

Clouds, which cover approximately 67% of the globe, serve as one of the major modulators in adjusting radiative energy on the Earth. Since rigorous radiative transfer computations including multiple scattering are costly, only absorption is considered in the longwave spectral bands in the radiation sub-models of the general circulation models (GCMs). Quantification of the effect of ignoring longwave scattering for flux and heating rate simulations is performed by using the GCM version of the Longwave Rapid Radiative Transfer Model (RRTMG_LW) with an implementation with the 16-stream Discrete Ordinates Radiative Transfer (DISORT) Program for a Multi-Layered Plane-Parallel Medium in conjunction with the 2010 CCCM products that merge satellite observations from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), the CloudSat, the Clouds and the Earth's Radiant Energy System (CERES) and the Moderate Resolution Imaging Spectrometer (MODIS). One-year global simulations show that neglecting longwave scattering overestimates upward flux at the top of the atmosphere (TOA) and underestimates downward flux at the surface by approximately 2.63 and 1.15 W/m2, respectively. Furthermore, when longwave scattering is included in the simulations, the tropopause is cooled by approximately 0.018 K/day and the surface is heated by approximately 0.028 K/day. As a result, the radiative effects of ignoring longwave scattering and doubling CO2 are comparable in magnitude.

Metabolite Depletion Affects Flux Profiling of Cell Lines

DEFF Research Database (Denmark)

Nilsson, A.; Haanstra, J. R.; Teusink, B.

2018-01-01

Quantifying the rate of consumption and release of metabolites (i.e., flux profiling) has become integral to the study of cancer. The fluxes as well as the growth of the cells may be affected by metabolite depletion during cultivation.......Quantifying the rate of consumption and release of metabolites (i.e., flux profiling) has become integral to the study of cancer. The fluxes as well as the growth of the cells may be affected by metabolite depletion during cultivation....

Rates of insulin secretion in INS-1 cells are enhanced by coupling to anaplerosis and Kreb’s cycle flux independent of ATP synthesis

International Nuclear Information System (INIS)

Cline, Gary W.; Pongratz, Rebecca L.; Zhao, Xiaojian; Papas, Klearchos K.

2011-01-01

Highlights: ► We studied media effects on mechanisms of insulin secretion of INS-1 cells. ► Insulin secretion was higher in DMEM than KRB despite identical ATP synthesis rates. ► Insulin secretion rates correlated with rates of anaplerosis and TCA cycle. ► Mitochondria metabolism and substrate cycles augment secretion signal of ATP. -- Abstract: Mechanistic models of glucose stimulated insulin secretion (GSIS) established in minimal media in vitro, may not accurately describe the complexity of coupling metabolism with insulin secretion that occurs in vivo. As a first approximation, we have evaluated metabolic pathways in a typical growth media, DMEM as a surrogate in vivo medium, for comparison to metabolic fluxes observed under the typical experimental conditions using the simple salt-buffer of KRB. Changes in metabolism in response to glucose and amino acids and coupling to insulin secretion were measured in INS-1 832/13 cells. Media effects on mitochondrial function and the coupling efficiency of oxidative phosphorylation were determined by fluorometrically measured oxygen consumption rates (OCRs) combined with 31 P NMR measured rates of ATP synthesis. Substrate preferences and pathways into the TCA cycle, and the synthesis of mitochondrial 2nd messengers by anaplerosis were determined by 13 C NMR isotopomer analysis of the fate of [U- 13 C] glucose metabolism. Despite similar incremental increases in insulin secretion, the changes of OCR in response to increasing glucose from 2.5 to 15 mM were blunted in DMEM relative to KRB. Basal and stimulated rates of insulin secretion rates were consistently higher in DMEM, while ATP synthesis rates were identical in both DMEM and KRB, suggesting greater mitochondrial uncoupling in DMEM. The relative rates of anaplerosis, and hence synthesis and export of 2nd messengers from the mitochondria were found to be similar in DMEM to those in KRB. And, the correlation of total PC flux with insulin secretion rates in DMEM

Internal targets for LEAR

International Nuclear Information System (INIS)

Kilian, K.; Gspann, J.; Mohl, D.; Poth, H.

1984-01-01

This chapter considers the use of thin internal targets in conjunction with phase-space cooling at the Low-Energy Antiproton Ring (LEAR). Topics considered include the merits of internal target operation; the most efficient use of antiprotons and of proton synchrotron (PS) protons, highest center-of-mass (c.m.) energy resolution; highest angular resolution and access to extreme angles; the transparent environment for all reaction products; a windowless source and pure targets; highest luminosity and count rates; access to lowest energies with increasing resolution; internal target thickness and vacuum requirements; required cooling performance; and modes of operation. It is demonstrated that an internal target in conjunction with phase-space cooling has the potential of better performance in terms of the economic use of antiprotons and consequently of PS protons; energy resolution; angular resolution; maximum reaction rate capability (statistical precision); efficient parasitic operation; transparency of the target for reaction products; access to low energies; and the ease of polarized target experiments. It is concluded that all p - experiments which need high statistics and high p - flux, such as studies of rare channels or broad, weak resonance structures, would profit from internal targets

The Influence of International Parity on the Exchange Rate: Purchasing Power Parity and International Fisher Effect

OpenAIRE

Oana Mionel

2012-01-01

This article assesses the impact of the inflation and interest rates on the exchange rates. The analysis tests the relation between the inflation rate and the exchange rate by applying the Purchasing Power Parity Theory, while the relation between the interest rate and the inflation rate is tested by applying the International Fisher Effect Theory. In order to test the Purchasing Power Parity the study takes into account the period of time between 1990 – 2009, and the following countries – th...

THE IMPLICATIONS OF VARYING EXCHANGE RATES FOR THE INTERNATIONAL TRADE

Directory of Open Access Journals (Sweden)

Sandu Carmen

2011-07-01

Full Text Available The benefit of international trade is a more efficient employment of the productive forces of the world. (John Stuart Mill The exchange rate is a primary factor that influences economy. This instrument is used by some countries in order to improve the lack of balance caused as a result of the financial crisis felt in many countries considered by then infallible. The negative effects of the financial crisis can also be found in the decreased volume of commodities involved in international trade exchanges, as a consequence of modified prices and decreased offer. The globalizing trend leads to a constant expansion of exchanges between countries and to the consolidation of international cooperation. Except that economic interdependence generates an increased risk under the influence of economic, financial, monetary or political factors. The currency risk can generate either a gain or loss during foreign trade operations. The long period of RON depreciation made possible the entry of Romanian products on the international markets due to their prices. Sheltered by the gain generated by the evolution of the exchange rate, most of the exporters were not concerned by the increase of product competitiveness or by avoiding the currency risk. The fact that, for many years, the evolution of the exchange rate generated substantial losses for the exporters shows that risk coverage in Romania is, in most cases, a purely theoretical concept.

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

Science.gov (United States)

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

2018-06-01

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

Effect of chamber enclosure time on soil respiration flux: A comparison of linear and non-linear flux calculation methods

DEFF Research Database (Denmark)

Kandel, Tanka P; Lærke, Poul Erik; Elsgaard, Lars

2016-01-01

One of the shortcomings of closed chamber methods for soil respiration (SR) measurements is the decreased CO2 diffusion rate from soil to chamber headspace that may occur due to increased chamber CO2 concentrations. This feedback on diffusion rate may lead to underestimation of pre-deployment flu......One of the shortcomings of closed chamber methods for soil respiration (SR) measurements is the decreased CO2 diffusion rate from soil to chamber headspace that may occur due to increased chamber CO2 concentrations. This feedback on diffusion rate may lead to underestimation of pre...... was placed on fixed collars, and CO2 concentration in the chamber headspace were recorded at 1-s intervals for 45 min. Fluxes were measured in different soil types (sandy, sandy loam and organic soils), and for various manipulations (tillage, rain and drought) and soil conditions (temperature and moisture......) to obtain a range of fluxes with different shapes of flux curves. The linear method provided more stable flux results during short enclosure times (few min) but underestimated initial fluxes by 15–300% after 45 min deployment time. Non-linear models reduced the underestimation as average underestimation...

An investigation of critical heat fluxes in vertical tubes internally cooled by Freon-12. Part I - Critical heat flux experiments with axially uniform and non-uniform heating and comparisons of data with selected correlations

International Nuclear Information System (INIS)

Green, W.J.; Stevens, J.R.

1981-08-01

Experiments have been performed using vertical heated tubes, cooled internally by Freon-12, to determine critical heat fluxes (CHFs) for both a uniformly heated section and an exit region with a separately controlled power supply. Heated lengths of the main separately were 2870 mm (8.48 and 16.76 mm tube bores) and 3700 mm (for 21.34 mm tube bore); heated length of the exit section was 230 mm. Coolant pressures, exit qualities and mass fluxes were in the range 0.9 to 1.3 MPa, 0.19 to 0.86, and 380 to 2800 kg m -2 s -1 , respectively. The data have been compared with published empirical correlations specifically formulated to predict CHFs in Freon-cooled, vertical tubes; relevant published CHF data have also been compared with these correlations. These comparisons show that, even over the ranges of conditions for which the correlations were developed, predicted values are only accurate to within +-20 per cent. Moreover, as mass fluxes increase above 3500 kg m -2 s -1 , the modified Groeneveld correlation becomes increasingly inadequate, and the Bertoletti and modified Bertoletti correlations under-predict CHF values by increasing amounts. At mass fluxes below 750 kg m -2 s -1 the Bertoletti correlations exhibit increasing inaccuracy with a decrease in mass flux. For non-uniform heating, the correlations are at variance with the experimental data

Effects of quartz on crystallization behavior of mold fluxes and microstructural characteristics of flux film.

Science.gov (United States)

Lei, Liu; Xiuli, Han; Mingduo, Li; Di, Zhang

2018-01-01

Mold fluxes are mainly prepared using cement clinker, quartz, wollastonite, borax, fluorite, soda ash and other mineral materials. Quartz, as one of the most common and essential materials, was chosen for this study to analyze itseffects on crystallization temperature, critical cooling rate, crystal incubation time, crystallization ratio and phases of flux film. We used the research methods of process mineralogy with the application of the single hot thermocouple technique, heat flux simulator, polarizing microscope, X-ray diffraction, etc. Results: By increasing the quartz content from 16 mass% to 24 mass%, the crystallization temperature, critical cooling rate and crystallization ratio of flux film decreased, and the crystal incubation time was extended. Meanwhile, the mineralogical structure of the flux film changed, with a large amount of wollastonite precipitation and a significant decrease in the cuspidine content until it reached zero. This showed a steady decline in the heat transfer control capacity of the flux film. The reason for the results above is that, by increasing the quartz content, the silicon-oxygen tetrahedron network structure promoted a rise in viscosity and restrained ion migration, inhibiting crystal nucleation and growth, leading to the weakening of the crystallization and a decline in the crystallization ratio.

Rates of insulin secretion in INS-1 cells are enhanced by coupling to anaplerosis and Kreb's cycle flux independent of ATP synthesis

Energy Technology Data Exchange (ETDEWEB)

Cline, Gary W., E-mail: gary.cline@yale.edu [The Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520 (United States); Department of Surgery, University of Minnesota-Twin Cities, Minneapolis, MN 55455 (United States); Pongratz, Rebecca L.; Zhao, Xiaojian [The Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520 (United States); Papas, Klearchos K. [Department of Surgery, University of Minnesota-Twin Cities, Minneapolis, MN 55455 (United States)

2011-11-11

Highlights: Black-Right-Pointing-Pointer We studied media effects on mechanisms of insulin secretion of INS-1 cells. Black-Right-Pointing-Pointer Insulin secretion was higher in DMEM than KRB despite identical ATP synthesis rates. Black-Right-Pointing-Pointer Insulin secretion rates correlated with rates of anaplerosis and TCA cycle. Black-Right-Pointing-Pointer Mitochondria metabolism and substrate cycles augment secretion signal of ATP. -- Abstract: Mechanistic models of glucose stimulated insulin secretion (GSIS) established in minimal media in vitro, may not accurately describe the complexity of coupling metabolism with insulin secretion that occurs in vivo. As a first approximation, we have evaluated metabolic pathways in a typical growth media, DMEM as a surrogate in vivo medium, for comparison to metabolic fluxes observed under the typical experimental conditions using the simple salt-buffer of KRB. Changes in metabolism in response to glucose and amino acids and coupling to insulin secretion were measured in INS-1 832/13 cells. Media effects on mitochondrial function and the coupling efficiency of oxidative phosphorylation were determined by fluorometrically measured oxygen consumption rates (OCRs) combined with {sup 31}P NMR measured rates of ATP synthesis. Substrate preferences and pathways into the TCA cycle, and the synthesis of mitochondrial 2nd messengers by anaplerosis were determined by {sup 13}C NMR isotopomer analysis of the fate of [U-{sup 13}C] glucose metabolism. Despite similar incremental increases in insulin secretion, the changes of OCR in response to increasing glucose from 2.5 to 15 mM were blunted in DMEM relative to KRB. Basal and stimulated rates of insulin secretion rates were consistently higher in DMEM, while ATP synthesis rates were identical in both DMEM and KRB, suggesting greater mitochondrial uncoupling in DMEM. The relative rates of anaplerosis, and hence synthesis and export of 2nd messengers from the mitochondria were found

Interaction of storage carbohydrates and other cyclic fluxes with central metabolism: A quantitative approach by non-stationary 13C metabolic flux analysis

Directory of Open Access Journals (Sweden)

C.A. Suarez-Mendez

2016-12-01

Full Text Available 13C labeling experiments in aerobic glucose limited cultures of Saccharomyces cerevisiae at four different growth rates (0.054; 0.101, 0.207, 0.307 h−1 are used for calculating fluxes that include intracellular cycles (e.g., storage carbohydrate cycles, exchange fluxes with amino acids, which are rearranged depending on the growth rate. At low growth rates the impact of the storage carbohydrate recycle is relatively more significant than at high growth rates due to a higher concentration of these materials in the cell (up to 560-fold and higher fluxes relative to the glucose uptake rate (up to 16%. Experimental observations suggest that glucose can be exported to the extracellular space, and that its source is related to storage carbohydrates, most likely via the export and subsequent extracellular breakdown of trehalose. This hypothesis is strongly supported by 13C-labeling experimental data, measured extracellular trehalose, and the corresponding flux estimations. Keywords: Non-stationary 13C labeling, Flux estimation, Trehalose, Glycogen, Amino acids

Supercharging an internal combustion engine by aid of a dual-rotor bi-flux axial compressor

Science.gov (United States)

Grǎdinariu, Andrei Cristian; Mihai, Ioan

2016-12-01

Internal combustion engines can be supercharged in order to enhance their performances [1-3]. Engine power is proportional to the quantity of fresh fluid introduced into the cylinder. At present, the general tendency is to try to obtain actual specific powers as high as possible, for as small as possible cylinder capacity, without increasing the generated pollution hazards. The present paper investigates the impact of replacing a centrifugal turbo-compressor with an axial double-rotor bi-flux one [4]. The proposed method allows that for the same number of cylinders, an increase in discharged airflow, accompanied by a decrease in fuel consumption. Using a program developed under the MathCad environment, the present work was aimed at studying the way temperature modifies at the end of isentropic compression under supercharging conditions. Taking into account a variation between extreme limits of the ambient temperature, its influence upon the evolution of thermal load coefficient was analyzed considering the air pressure at the compressor cooling system outlet. This analysis was completed by an exergetical study of the heat evacuated through cylinder walls in supercharged engine conditions. The conducted investigation allows verification of whether significant differences can be observed between an axial, dual-rotor, bi-flux compressor and centrifugal compressors.

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.

Magnetic fusion energy plasma interactive and high heat flux components. Volume III. Strategy for international collaborations in the areas of plasma materials interactions and high heat flux materials and components development

International Nuclear Information System (INIS)

Gauster, W.B.; Bauer, W.; Roberto, J.B.; Post, D.E.

1984-01-01

The purpose of this summary is to assess opportunities for such collaborations in the specific areas of Plasma Materials Interaction and High Heat Flux Materials and Components Development, and to aid in developing a strategy to take advantage of them. After some general discussion of international collaborations, we summarize key technical issues and the US programs to address them. Then follows a summary of present collaborations and potential opportunities in foreign laboratories

Flux schemes based finite volume method for internal transonic flow with condensation

Czech Academy of Sciences Publication Activity Database

Halama, Jan; Benkhaldoun, F.; Fořt, J.

2011-01-01

Roč. 65, č. 8 (2011), s. 953-968 ISSN 0271-2091 Institutional research plan: CEZ:AV0Z20760514 Keywords : VFFC flux * SRNH flux * two-phase homogeneous flow * fractional step method * condensation Subject RIV: BK - Fluid Dynamics Impact factor: 1.176, year: 2011

FLUXNET. Database of fluxes, site characteristics, and flux-community information

Energy Technology Data Exchange (ETDEWEB)

Olson, R. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holladay, S. K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cook, R. B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Falge, E. [Univ. Bayreuth, Bayreuth (Germany); Baldocchi, D. [Univ. of California, Berkeley, CA (United States); Gu, L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2004-02-28

FLUXNET is a “network of regional networks” created by international scientists to coordinate regional and global analysis of observations from micrometeorological tower sites. The flux tower sites use eddy covariance methods to measure the exchanges of carbon dioxide (CO₂), water vapor, and energy between terrestrial ecosystems and the atmosphere. FLUXNET’S goals are to aid in understanding the mechanisms controlling the exchanges of CO₂, water vapor, and energy across a range of time (0.5 hours to annual periods) and space scales. FLUXNET provides an infrastructure for the synthesis and analysis of world-wide, long-term flux data compiled from various regional flux networks. Information compiled by the FLUXNET project is being used to validate remote sensing products associated with the National Aeronautics and Space Administration (NASA) Terra and Aqua satellites. FLUXNET provides access to ground information for validating estimates of net primary productivity, and energy absorption that are being generated by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors. In addition, this information is also used to develop and validate ecosystem models.

Integrated leak rate testing of the fast flux test facility reactor containment building

International Nuclear Information System (INIS)

James, E.B.; Farabee, O.A.; Bliss, R.J.

1978-01-01

The initial Integrated Leak Rate Test (ILRT) of the Fast Flux Test Facility containment building was performed from May 27 to June 2, 1978. The test was conducted in air with systems vented and with the containment recirculating coolers in operation. 10 psig and 5 psig tests were run using the absolute pressure test method. The measured leakage rates were .033% Vol/24 hr. and -.0015% Vol/24 hrs. respectively. Subsequent verification tests at both 10 psig and 5 psig proved that the test equipment was operating properly and it was sensitive enough to detect leaks at low pressures. This ILRT was performed at a lower pressure than any previous ILRT on a reactor containment structure in the United States. While the initial design requirements for ice condenser containments called for a part pressure test at 6 psig, the tests were waived due to the apparent statistical problems of data analysis and the repeatability of the data itself at such low pressure. In contrast to this belief, both the 5 and 10 psig ILRT's were performed in a successful manner at FFTF

Studies on muon tomography for archaeological internal structures scanning

Science.gov (United States)

Gómez, H.; Carloganu, C.; Gibert, D.; Jacquemier, J.; Karyotakis, Y.; Marteau, J.; Niess, V.; Katsanevas, S.; Tonazzo, A.

2016-05-01

Muon tomography is a potential non-invasive technique for internal structure scanning. It has already interesting applications in geophysics and can be used for archaeological purposes. Muon tomography is based on the measurement of the muon flux after crossing the structure studied. Differences on the mean density of these structures imply differences on the detected muon rate for a given direction. Based on this principle, Monte Carlo simulations represent a useful tool to provide a model of the expected muon rate and angular distribution depending on the composition of the studied object, being useful to estimate the expected detected muons and to better understand the experimental results. These simulations are mainly dependent on the geometry and composition of the studied object and on the modelling of the initial muon flux at surface. In this work, the potential of muon tomography in archaeology is presented and evaluated with Monte Carlo simulations by estimating the differences on the muon rate due to the presence of internal structures and its composition. The influence of the chosen muon model at surface in terms of energy and angular distributions in the final result has been also studied.

Tropical Gravity Wave Momentum Fluxes and Latent Heating Distributions

Science.gov (United States)

Geller, Marvin A.; Zhou, Tiehan; Love, Peter T.

2015-01-01

Recent satellite determinations of global distributions of absolute gravity wave (GW) momentum fluxes in the lower stratosphere show maxima over the summer subtropical continents and little evidence of GW momentum fluxes associated with the intertropical convergence zone (ITCZ). This seems to be at odds with parameterizations forGWmomentum fluxes, where the source is a function of latent heating rates, which are largest in the region of the ITCZ in terms of monthly averages. The authors have examined global distributions of atmospheric latent heating, cloud-top-pressure altitudes, and lower-stratosphere absolute GW momentum fluxes and have found that monthly averages of the lower-stratosphere GW momentum fluxes more closely resemble the monthly mean cloud-top altitudes rather than the monthly mean rates of latent heating. These regions of highest cloud-top altitudes occur when rates of latent heating are largest on the time scale of cloud growth. This, plus previously published studies, suggests that convective sources for stratospheric GW momentum fluxes, being a function of the rate of latent heating, will require either a climate model to correctly model this rate of latent heating or some ad hoc adjustments to account for shortcomings in a climate model's land-sea differences in convective latent heating.

DEVELOPMENT OF FLUORINE-FREE MOULD FLUX APPLIED IN LOW CARBON STEEL

Directory of Open Access Journals (Sweden)

Jayme Alves de Souza Junior

2012-12-01

Full Text Available ract The mould flux is a mixture of non-metallic oxides that, in contact with liquid steel melts, becomes a liquid slag which the mainly function is to lubricate and control heat transfer between mould and strand during the continuous casting process. The mould flux without fluoride has the advantage of decreasing the wear of machine and the SEN in comparison to common mould flux. The application in Continuous Casting of Slabs has been a great challenge in relation to the operational viability together with internal and surface quality of slabs. Another differential is the decrease of environmental issues on account of the contamination of secondary cooling water by the fluorides. It is considered that properties of mould flux as chemical composition, viscosity, softening, melting flowing temperatures, fusion rate, etc, should be suitable to the chemical composition and the mechanical properties at elevated temperatures of steel and also the operational parameters such as casting temperature, casting speed, mould frequency, among others. This work presents a preliminary analysis in relation to operational viability, analysis of surface quality of slabs, measurements of fluorides content in the water of secondary cooling of machine. In addition to that, the analyses of operational features as measurements of wear of SEN, mould flux consumption, slag pool and behavior of thermocouples of detection system break outs (MSD are considered.

Interaction of storage carbohydrates and other cyclic fluxes with central metabolism: A quantitative approach by non-stationary 13C metabolic flux analysis.

Science.gov (United States)

Suarez-Mendez, C A; Hanemaaijer, M; Ten Pierick, Angela; Wolters, J C; Heijnen, J J; Wahl, S A

2016-12-01

13 C labeling experiments in aerobic glucose limited cultures of Saccharomyces cerevisiae at four different growth rates (0.054; 0.101, 0.207, 0.307 h -1 ) are used for calculating fluxes that include intracellular cycles (e.g., storage carbohydrate cycles, exchange fluxes with amino acids), which are rearranged depending on the growth rate. At low growth rates the impact of the storage carbohydrate recycle is relatively more significant than at high growth rates due to a higher concentration of these materials in the cell (up to 560-fold) and higher fluxes relative to the glucose uptake rate (up to 16%). Experimental observations suggest that glucose can be exported to the extracellular space, and that its source is related to storage carbohydrates, most likely via the export and subsequent extracellular breakdown of trehalose. This hypothesis is strongly supported by 13 C-labeling experimental data, measured extracellular trehalose, and the corresponding flux estimations.

U(1) mediation of flux supersymmetry breaking

Science.gov (United States)

Grimm, Thomas W.; Klemm, Albrecht

2008-10-01

We study the mediation of supersymmetry breaking triggered by background fluxes in Type II string compactifications with Script N = 1 supersymmetry. The mediation arises due to an U(1) vector multiplet coupling to both a hidden supersymmetry breaking flux sector and a visible D-brane sector. The required internal manifolds can be constructed by non-Kähler resolutions of singular Calabi-Yau manifolds. The effective action encoding the U(1) coupling is then determined in terms of the global topological properties of the internal space. We investigate suitable local geometries for the hidden and visible sector in detail. This includes a systematic study of orientifold symmetries of del Pezzo surfaces realized in compact geometries after geometric transition. We construct compact examples admitting the key properties to realize flux supersymmetry breaking and U(1) mediation. Their toric realization allows us to analyze the geometry of curve classes and confirm the topological connection between the hidden and visible sector.

U(1) mediation of flux supersymmetry breaking

International Nuclear Information System (INIS)

Grimm, Thomas W.; Klemm, Albrecht

2008-01-01

We study the mediation of supersymmetry breaking triggered by background fluxes in Type II string compactifications with N = 1 supersymmetry. The mediation arises due to an U(1) vector multiplet coupling to both a hidden supersymmetry breaking flux sector and a visible D-brane sector. The required internal manifolds can be constructed by non-Kaehler resolutions of singular Calabi-Yau manifolds. The effective action encoding the U(1) coupling is then determined in terms of the global topological properties of the internal space. We investigate suitable local geometries for the hidden and visible sector in detail. This includes a systematic study of orientifold symmetries of del Pezzo surfaces realized in compact geometries after geometric transition. We construct compact examples admitting the key properties to realize flux supersymmetry breaking and U(1) mediation. Their toric realization allows us to analyze the geometry of curve classes and confirm the topological connection between the hidden and visible sector.

APPLE-3: improvement of APPLE for neutron and gamma-ray flux, spectrum and reaction rate plotting code, and of its code manual

International Nuclear Information System (INIS)

Kawasaki, Hiromitu; Maki, Koichi; Seki, Yasushi.

1991-03-01

A code APPLE was produced in 1976 for calculating and plotting tritium breeding ratio and tritium production rate distributions. That code was improved as 'APPLE-2' in 1982, to calculate and plot not only tritium breeding ratio but also distributions of neutron and gamma-ray fluxes, their spectra, nuclear heating rates and other reaction rates, and dose rate distributions during operation and after shutdown in 1982. The code APPLE-2 can calculate and plot these nuclear properties derived from neutron and gamma-ray fluxes by ANISN (one dimensional transport code), DOT3.5 (two dimensional transport code) and MORSE (three dimensional Monte Carlo code). We revised the code APPLE-2 as 'APPLE-3' by adding many functions to the APPLE-2 code in accordance with users' requirements proposed in recent progress of fusion reaction nuclear design. With minor modification of APPLE-2, a number of inconsistencies have been found between the code manual and the input data in the code. In the present report, the new functions added to APPLE-2 and improved users' manual are explained. (author)

Increasing flux rate to shorten leaching period and ramp-up production

Science.gov (United States)

Ngantung, Billy; Agustin, Riska; Ravi'i

2017-01-01

J Resources Bolaang Mongondow (JBRM) has operated a dynamic heap leach in its Bakan Gold Mine since late 2013. After successfully surpassing its name plate capacity of 2.6 MT/annum in 2014, the clayey and transition ore become the next operational challenge. The presence of transition and clayey ore requires longer leaching period, hence reducing the leach pad capacity which then caused reduced production. Maintaining or even increasing production with such longer leaching ore types can be done by expanding the leach pad area which means an additional capital investment, and/or shortening the leaching cycle which compromise a portion of gold extraction. JBRM has been successfully increasing the leach pad production from 2.6 MT/annum to 3.8 MT/annum, whilst improving the gold extraction from around 70% to around 80%. This was achieved by managing the operation of the leach pad which is shortening the leach cycle by identifying and combining the optimal flux rate application versus the tonne processed in each cell, at no capital investment for expanding the cell capacity.

Flame spread over electrical wire with AC electric fields: Internal circulation, fuel vapor-jet, spread rate acceleration, and molten insulator dripping

KAUST Repository

Lim, Seungjae

2015-04-01

The effect of electric field on the characteristics of flame spread along a polyethylene (PE) insulated electrical wire was investigated experimentally by varying the AC frequency and voltage applied to the wire. The results showed that the flame spread rate was accelerated due to the convergence of electric flux near the end of wire, having three distinct regimes depending on applied voltage. In each regime, several subregimes could be identified depending on AC frequency. Flame shape (height and width) and slanted direction of the spreading flame were influenced differently. Fuel-vapor jets were ejected from the molten PE surface even for the baseline case without the application of an electric field; this could be attributed to the bursting of fuel vapor bubbles generated from internal boiling at the molten PE surface. An internal circulation of molten-PE was also observed as a result of non-uniform heating by the spreading flame. In the high voltage regime with a high AC frequency, excessive dripping of molten PE led to flame extinction.

(Devaluing Intern Labour: Journalism Internship Pay Rates and Collective Representation in Canada

Directory of Open Access Journals (Sweden)

Errol Salamon

2015-09-01

Full Text Available Unpaid journalism internships have attracted increasing media coverage, but they have received limited scholarly attention. This paper traces the connections between trade unions (in unionized media organizations and the labour conditions marking journalism internships. While some unions can be complicit in sustaining the exploitation and devaluation of interns with regard to the standard market value of entry-level labour, other unions have fought to establish internships, locking higher salaries into collective agreements. Building on the concept of precarity, this article surveys internships at 19 mainstream English-language newspapers and magazines in Canada. It draws on documentary evidence from and personal communication with labour unions and journalism organizations, internship advertisements, and media coverage to offer a typology of the relationships between pay rates and collective representation within journalism internships: unpaid/low paid and not under union jurisdiction; unpaid/low paid and under union jurisdiction; paid at intern rates and not under union jurisdiction; paid at intern rates and under union jurisdiction; and paid at entry-level employee rates and under union jurisdiction.

14 CFR 399.41 - Zones of limited suspension for international cargo rates.

Science.gov (United States)

2010-01-01

... TRANSPORTATION (AVIATION PROCEEDINGS) POLICY STATEMENTS STATEMENTS OF GENERAL POLICY Policies Relating to Rates and Tariffs § 399.41 Zones of limited suspension for international cargo rates. (a) Applicability. This section states the Board's policy for suspending rate changes for the transportation of property...

Differentiating transpiration from evaporation in seasonal agricultural wetlands and the link to advective fluxes in the root zone

International Nuclear Information System (INIS)

Bachand, P.A.M.; Bachand, S.; Fleck, J.; Anderson, F.; Windham-Myers, L.

2014-01-01

internal root zone cycling of Hg and other dissolved constituents, benthic fluxes, and biological irrigation may be greatly affected. - Highlights: • PFR model utilizes EC as conservative tracer to calculate transpiration rates. • Wetland transpiration causes significant summertime percolation into the root zone. • A Peclet number equivalent relationship is derived for evaluating root zone fluxes. • Transpiration affects soil diffusive and advective flux vertical distribution. • Transpiration causes seasonal/diel trends in benthic fluxes of Hg and other constituents

Flux of Cadmium through Euphausiids

International Nuclear Information System (INIS)

Benayoun, G.; Fowler, S.W.; Oregioni, B.

1976-01-01

Flux of the heavy metal cadmium through the euphausiid Meganyctiphanes norvegica was examined. Radiotracer experiments showed that cadmium can be accumulated either directly from water or through the food chain. When comparing equilibrium cadmium concentration factors based on stable element measurements with those obtained from radiotracer experiments, it is evident that exchange between cadmium in the water and that in euphausiid tissue is a relatively slow process, indicating that, in the long term, ingestion of cadmium will probably be the more important route for the accumulation of this metal. Approximately 10% of cadmium ingested by euphausiids was incorporated into internal tissues when the food source was radioactive Artemia. After 1 month cadmium, accumulated directly from water, was found to be most concentrated in the viscera with lesser amounts in eyes, exoskeleton and muscle, respectively. Use of a simple model, based on the assumption that cadmium taken in by the organism must equal cadmium released plus that accumulated in tissue, allowed assessment of the relative importance of various metabolic parameters in controlling the cadmium flux through euphausiids. Fecal pellets, due to their relatively high rate of production and high cadmium content, accounted for 84% of the total cadmium flux through M. norvegica. Comparisons of stable cadmium concentrations in natural euphausiid food and the organism's resultant fecal pellets indicate that the cadmium concentration in ingested material was increased nearly 5-fold during its passage through the euphausiid. From comparisons of all routes by which cadmium can be released from M. norvegica to the water column, it is concluded that fecal pellet deposition represents the principal mechanism effecting the downward vertical transport of cadmium by this species. (author)

International finance, Lévy distributions, and the econophysics of exchange rates

Science.gov (United States)

Da Silva, Sergio; Matsushita, Raul; Gleria, Iram; Figueiredo, Annibal; Rathie, Pushpa

2005-06-01

This paper surveys the developments in the field of international finance, in particular the research of economists on foreign exchange rates. That might be of interest to physicists working on the econophysics of exchange rates. We show how the econophysics agenda might follow naturally from the economists' research. We also present our own work on the econophysics of exchange rates.

The Concept of State Capacity: Comparative International Ratings against State Legitimacy

Directory of Open Access Journals (Sweden)

Vladimir Gennadievich Ivanov

2015-12-01

Full Text Available In the given article, the author analyzes the concept of state capacity, widely popular among political scientists and international relations specialists. The author proves that the evaluations of the level of state capacity of the developing and postcommunist countries based on popular comparative ratings are generally biased because of methodological defects and discrepancy of the whole theory as well as politicization and indoctrination of the given ratings. The negative evaluations of the quality of the government and state capacity of a country could be used to discredit and delegitimize the political regime as well as substantiation of mass protests and color revolutions and a tool of information war. The author concludes that numerous comparative international ratings are often used as a tool of political influence.

Background internal dose rates of earthworm and arthropod species in the forests of Aomori, Japan

International Nuclear Information System (INIS)

Ohtsuka, Yoshihito; Takaku, Yuichi; Hisamatsu, Shun'ichi

2013-01-01

We measured naturally occurring radionuclides in samples from an earthworm species and 11 arthropod species collected in coniferous forests in Rokkasho, Aomori, Japan, to assess background internal radiation dose rates. The rates were calculated from the measured concentrations of the radionuclides and dose coefficients from the literature. The mean internal dose rate of composite earthworm samples was 0.35 μGy h -1 , whereas the mean dose rates of the arthropod samples ranged from 36 nGy h -1 to 0.79 μGy h -1 . Polonium-210 was the radionuclide with the highest contribution to the internal dose rate for all the species, except the longhorn beetle. (author)

Mesoscopic fluctuations in biharmonically driven flux qubits

Science.gov (United States)

Ferrón, Alejandro; Domínguez, Daniel; Sánchez, María José

2017-01-01

We investigate flux qubits driven by a biharmonic magnetic signal, with a phase lag that acts as an effective time reversal broken parameter. The driving induced transition rate between the ground and the excited state of the flux qubit can be thought of as an effective transmittance, profiting from a direct analogy between interference effects at avoided level crossings and scattering events in disordered electronic systems. For time scales prior to full relaxation, but large compared to the decoherence time, this characteristic rate has been accessed experimentally by Gustavsson et al. [Phys. Rev. Lett. 110, 016603 (2013)], 10.1103/PhysRevLett.110.016603 and its sensitivity with both the phase lag and the dc flux detuning explored. In this way, signatures of universal conductance fluctuationslike effects have been analyzed and compared with predictions from a phenomenological model that only accounts for decoherence, as a classical noise. Here we go beyond the classical noise model and solve the full dynamics of the driven flux qubit in contact with a quantum bath employing the Floquet-Born-Markov master equation. Within this formalism, the computed relaxation and decoherence rates turn out to be strongly dependent on both the phase lag and the dc flux detuning. Consequently, the associated pattern of fluctuations in the characteristic rates display important differences with those obtained within the mentioned phenomenological model. In particular, we demonstrate the weak localizationlike effect in the average values of the relaxation rate. Our predictions can be tested for accessible but longer time scales than the current experimental times.

Magnetic Flux Conversion in the DIII-D Steady-State Hybrid Scenario

Science.gov (United States)

Taylor, N. Z.; Luce, T. C.; La Haye, R. J.; Petty, C. C.; Nazikian, R.

2017-10-01

The hybrid is a promising high confinement scenario for ITER. The broader current profile aids discharge sustainment by raising qmin > 1 thereby avoiding sawtooth-triggered 2/1 tearing modes. In DIII-D hybrid scenario discharges, the rate of poloidal magnetic energy consumption is more than the rate of energy flow from the poloidal field coils. This is evidence that there is a conversion of toroidal flux to poloidal flux, which may be responsible for the anomalous broadening of the current profile known as flux pumping. The rate of poloidal flux being provided and consumed was tracked with coil and kinetic flux states. During long stationary intervals (1.5 seconds) with constant stored magnetic energy, a significant flux state deficit rate >10 mV was observed. The inequality in the evolution of the flux states was observed in hybrids that were 100% non-inductive and with successful RMP ELM suppression. Work supported by the US DOE under DE-FC02-04ER54698 and DE-AC05-06OR23100.

Assessing the applicability of the 1D flux theory to full-scale secondary settling tank design with a 2D hydrodynamic model.

Science.gov (United States)

Ekama, G A; Marais, P

2004-02-01

The applicability of the one-dimensional idealized flux theory (1DFT) for the design of secondary settling tanks (SSTs) is evaluated by comparing its predicted maximum surface overflow (SOR) and solids loading (SLR) rates with that calculated with the two-dimensional computational fluid dynamics model SettlerCAD using as a basis 35 full-scale SST stress tests conducted on different SSTs with diameters from 30 to 45m and 2.25-4.1m side water depth (SWD), with and without Stamford baffles. From the simulations, a relatively consistent pattern appeared, i.e. that the 1DFT can be used for design but its predicted maximum SLR needs to be reduced by an appropriate flux rating, the magnitude of which depends mainly on SST depth and hydraulic loading rate (HLR). Simulations of the Watts et al. (Water Res. 30(9)(1996)2112) SST, with doubled SWDs and the Darvill new (4.1m) and old (2.5m) SSTs with interchanged depths, were run to confirm the sensitivity of the flux rating to depth and HLR. Simulations with and without a Stamford baffle were also performed. While the design of the internal features of the SST, such as baffling, has a marked influence on the effluent SS concentration while the SST is underloaded, these features appeared to have only a small influence on the flux rating, i.e. capacity, of the SST. Until more information is obtained, it would appear from the simulations that the flux rating of 0.80 of the 1DFT maximum SLR recommended by Ekama and Marais (Water Pollut. Control 85(1)(1986)101) remains a reasonable value to apply in the design of full-scale SSTs-for deep SSTs (4m SWD) the flux rating could be increased to 0.85 and for shallow SSTs (2.5m SWD) decreased to 0.75. It is recommended that (i) while the apparent interrelationship between SST flux rating and depth suggests some optimization of the volume of the SST, this be avoided and (ii) the depth of the SST be designed independently of the surface area as is usually the practice and once selected, the

Dry-out heat fluxes of falling film and low-mass flux upward-flow in heated tubes

International Nuclear Information System (INIS)

Koizumi, Yasuo; Ueda, Tatsuhiro; Matsuo, Teruyuki; Miyota, Yukio

1998-01-01

Dry-out heat fluxes were investigated experimentally for a film flow falling down on the inner surface of vertical heated-tubes and for a low mass flux forced-upward flow in the tubes using R 113. This work followed the study on those for a two-phase natural circulation system. For the falling film boiling, flow state observation tests were also performed, where dry-patches appearing and disappearing repeatedly were observed near the exit end of the heated section at the dry-out heat flux conditions. Relation between the dry-out heat flux and the liquid film flow rate is analyzed. The dry-out heat fluxes of the low mass flux upflow are expressed well by the correlation proposed in the previous work. The relation for the falling film boiling shows a similar trend to that for the upflow boiling, however, the dry-out heat fluxes of the falling film are much lower, approximately one third, than those of the upward flow. (author)

Background internal dose rates of earthworm and arthropod species in the forests of Aomori, Japan

International Nuclear Information System (INIS)

Yoshihito Ohtsuka; Yuichi Takaku; Shun'ichi Hisamatsu

2015-01-01

In this study, we measured the concentrations of several natural radionuclides in samples of one earthworm species and 11 arthropod species collected from four coniferous forests in Rokkasho, Aomori Prefecture, Japan, and we assessed the background internal radiation dose rate for each species. Dose rates were calculated by using the radionuclide concentrations in the samples and dose conversion coefficients obtained from the literature. The mean internal dose rate in the earthworm species was 0.28 μGy h -1 , and the mean internal dose rates in the arthropod species ranged between 0.036 and 0.69 μGy h -1 . (author)

Full text publication rates of studies presented at an international emergency medicine scientific meeting.

Science.gov (United States)

Chan, Jannet W M; Graham, Colin A

2011-09-01

The publication rate of full text papers following an abstract presentation at a medical conference is variable, and few studies have examined the situation with respect to international emergency medicine conferences. This retrospective study aimed to identify the publication rate of abstracts presented at the 2006 International Conference on Emergency Medicine (ICEM) held in Halifax, Canada. The full text publication rate was 33.2%, similar to previous emergency medicine meetings. English language barriers may play a role in the low publication rate seen.

Overview of the 2013 FireFlux II grass fire field experiment

Science.gov (United States)

C.B. Clements; B. Davis; D. Seto; J. Contezac; A. Kochanski; J.-B. Fillipi; N. Lareau; B. Barboni; B. Butler; S. Krueger; R. Ottmar; R. Vihnanek; W.E. Heilman; J. Flynn; M.A. Jenkins; J. Mandel; C. Teske; D. Jimenez; J. O' Brien; B. Lefer

2014-01-01

In order to better understand the dynamics of fire-atmosphere interactions and the role of micrometeorology on fire behaviour the FireFlux campaign was conducted in 2006 on a coastal tall-grass prairie in southeast Texas, USA. The FireFlux campaign dataset has become the international standard for evaluating coupled fire-atmosphere model systems. While FireFlux is one...

Fast nanoscale heat-flux modulation with phase-change materials

OpenAIRE

Van Zwol , Pieter; Joulain , Karl; Ben-Abdallah , Philippe; Greffet , Jean-Jacques; Chevrier , Joël

2011-01-01

International audience; We introduce a new concept for electrically controlled heat flux modulation. A flux contrast larger than 10 dB is expected with switching time on the order of tens of nanoseconds. Heat flux modulation is based on the interplay between radiative heat transfer at the nanoscale and phase change materials. Such large contrasts are not obtainable in solids, or in far field. As such this opens up new horizons for temperature modulation and actuation at the nanoscale.

Flux distribution measurements in the Bruce B Unit 6 reactor using a transportable traveling flux detector system

International Nuclear Information System (INIS)

Leung, T.C.; Drewell, N.H.; Hall, D.S.; Lopez, A.M.

1987-01-01

A transportable traveling flux detector (TFD) system for use in power reactors has been developed and tested at Chalk River Nuclear Labs. in Canada. It consists of a miniature fission chamber, a motor drive mechanism, a computerized control unit, and a data acquisition subsystem. The TFD system was initially designed for the in situ calibration of fixed self-powered detectors in operating power reactors and for flux measurements to verify reactor physics calculations. However, this system can also be used as a general diagnostic tool for the investigation of apparent detector failures and flux anomalies and to determine the movement of reactor internal components. This paper describes the first successful use of the computerized TFD system in an operating Canada deuterium uranium (CANDU) power reactor and the results obtained from the flux distribution measurements. An attempt is made to correlate minima in the flux profile with the locations of fuel channels so that future measurements can be used to determine the sag of the channels. Twenty-seven in-core flux detector assemblies in the 855-MW (electric) Unit 6 reactor of the Ontario Hydro Bruce B Generating Station were scanned

International comparisons of preterm birth: higher rates of late preterm birth are associated with lower rates of stillbirth and neonatal death.

Science.gov (United States)

Lisonkova, S; Sabr, Y; Butler, B; Joseph, K S

2012-12-01

To examine international rates of preterm birth and potential associations with stillbirths and neonatal deaths at late preterm and term gestation. Ecological study. Canada, USA and 26 countries in Europe. All deliveries in 2004. Information on preterm birth (Statistics Canada, the EURO-PERISTAT project and the National Center for Health Statistics. Pearson correlation coefficients and random-intercept Poisson regression were used to examine the association between preterm birth rates and gestational age-specific stillbirth and neonatal death rates. Rate ratios with 95% confidence intervals were estimated after adjustment for maternal age, parity and multiple births. Stillbirths and neonatal deaths ≥ 32 and ≥ 37 weeks of gestation. International rates of preterm birth (births. Preterm birth rates at 32-36 weeks were inversely associated with stillbirths at ≥ 32 weeks (adjusted rate ratio 0.94, 95% CI 0.92-0.96) and ≥ 37 weeks (adjusted rate ratio 0.88, 95% CI 0.85-0.91) of gestation and inversely associated with neonatal deaths at ≥ 32 weeks (adjusted rate ratio 0.88, 95% CI 0.85-0.91) and ≥ 37 weeks (adjusted rate ratio 0.82, 95% CI 0.78-0.86) of gestation. Countries with high rates of preterm birth at 32-36 weeks of gestation have lower stillbirth and neonatal death rates at and beyond 32 weeks of gestation. Contemporary rates of preterm birth are indicators of both perinatal health and obstetric care services. © 2012 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2012 RCOG.

Hypnosis modulates behavioural measures and subjective ratings about external and internal awareness.

Science.gov (United States)

Demertzi, Athena; Vanhaudenhuyse, Audrey; Noirhomme, Quentin; Faymonville, Marie-Elisabeth; Laureys, Steven

2015-12-01

In altered subjective states, the behavioural quantification of external and internal awareness remains challenging due to the need for reports on the subjects' behalf. With the aim to characterize the behavioural counterpart of external and internal awareness in a modified subjective condition, we used hypnosis during which subjects remain fully responsive. Eleven right-handed subjects reached a satisfactory level of hypnotisability as evidenced by subjective reports on arousal, absorption and dissociation. Compared to normal wakefulness, in hypnosis (a) participants' self-ratings for internal awareness increased and self-ratings for external awareness decreased, (b) the two awareness components tended to anticorrelate less and the switches between external and internal awareness self-ratings were less frequent, and (c) participants' reaction times were higher and lapses in key presses were more frequent. The identified imbalance between the two components of awareness is considered as of functional relevance to subjective (meta)cognition, possibly mediated by allocated attentional properties brought about by hypnosis. Our results highlight the presence of a cognitive counterpart in resting state, indicate that the modified contents of awareness are measurable behaviourally, and provide leverage for investigations of more challenging altered conscious states, such as anaesthesia, sleep and disorders of consciousness. Copyright © 2015 Elsevier Ltd. All rights reserved.

Seasonal variations of nitrous oxide fluxes and soil denitrification rates in subtropical freshwater and brackish tidal marshes of the Min River estuary.

Science.gov (United States)

Wang, Xuming; Hu, Minjie; Ren, Hongchang; Li, Jiabing; Tong, Chuan; Musenze, Ronald S

2018-03-01

Estuarine tidal marshes provide favorable conditions for nitrous oxide (N 2 O) production. Saltwater intrusion caused by sea-level rise would exert complex effects on the production and emission of N 2 O in estuarine tidal marshes; however, few studies have been conducted on its effects on N 2 O emissions. Salinity gradients are a common occurrence in estuarine tidal marshes. Studies on production and emission of N 2 O in tidal marshes with different salinities may elucidate the impact of saltwater intrusion on the emission of greenhouse gases. This study explores the seasonal variations of N 2 O fluxes and soil denitrification rates in freshwater (Daoqingzhou wetland) and brackish (Shanyutan wetland) tidal marshes dominated by Cyperus malaccensis var. brevifolius (shichito matgrass) in the Min River estuary, southeastern China. N 2 O fluxes in both marshes showed strong temporal variability. The highest N 2 O fluxes were observed in the hot and wet summer months, whereas the lowest fluxes were observed in the cold winter and autumn months. N 2 O fluxes from the freshwater marsh (48.81±9.01μgm -2 h -1 ) were significantly higher (ptidal wetlands and exert a negative feedback on the climate system. Copyright © 2017 Elsevier B.V. All rights reserved.

Hydrothermal element fluxes from Copahue, Argentina: A "beehive" volcano in turmoil

Science.gov (United States)

Varekamp, J.C.; Ouimette, A.P.; Herman, S.W.; Bermudez, A.; Delpino, D.

2001-01-01

Copahue volcano erupted altered rock debris, siliceous dust, pyroclastic sulfur, and rare juvenile fragments between 1992 and 1995, and magmatic eruptions occurred in July-October 2000. Prior to 2000, the Copahue crater lake, acid hot springs, and rivers carried acid brines with compositions that reflected close to congruent rock dissolution. The ratio between rock-forming elements and chloride in the central zone of the volcano-hydrothermal system has diminished over the past few years, reflecting increased water/rock ratios as a result of progressive rock dissolution. Magmatic activity in 2000 provided fresh rocks for the acid fluids, resulting in higher ratios between rock-forming elements and chloride in the fluids and enhanced Mg fluxes. The higher Mg fluxes started several weeks prior to the eruption. Model data on the crater lake and river element flux determinations indicate that Copahue volcano was hollowed out at a rate of about 20 000-25 000 m3/yr, but that void space was filled with about equal amounts of silica and liquid elemental sulfur. The extensive rock dissolution has weakened the internal volcanic structure, making flank collapse a volcanic hazard at Copahue.

International interest rate convergence: a survey of the issues and evidence

OpenAIRE

Charles Pigott

1993-01-01

World financial markets have become substantially integrated over the last two decades. Contrary to widespread expectations, however, this integration has not led to any greater convergence of interest rates across countries. This article examines why convergence has not occurred and more generally what financial integration does—and does not—mean for international interest rate relations.

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...

A review of fatal accident incidence rate trends in fishing international

DEFF Research Database (Denmark)

Jensen, Olaf; Pétursdóttir, G; Abrahamsen, Annbjørg

2014-01-01

Background. Injury prevention in fishing is one of the most important occupational health challenges. The aim was to describe and compare internationally the trends of the fatal injury incidence rates and to discuss the impact of the implemented safety programs. Methods. The review is based...... on journal articles and reports from the maritime authorities in Poland, UK, Norway, Iceland, Denmark, US and Alaska and Canada. The original incidence rates were recalculated as per 1000 person-years for international comparison of the trends. Results. The risk of fatal accidents in fishing in the northern...... countries has been reduced by around 50% to an average of about 1 per 1000 person-years. Norway and Canada keep the lowest rates with around 0.5 and 0.25 per 1000 person-years. About half of the fatal injuries are related to vessel disasters and drowning. The safety programs seem to have good effects still...

76 FR 6128 - Energy Exchange International, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

Science.gov (United States)

2011-02-03

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-2730-000] Energy Exchange International, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... proceeding Energy Exchange International, LLC's application for market-based rate authority, with an...

Metabolic-flux dependent regulation of microbial physiology.

Science.gov (United States)

Litsios, Athanasios; Ortega, Álvaro D; Wit, Ernst C; Heinemann, Matthias

2018-04-01

According to the most prevalent notion, changes in cellular physiology primarily occur in response to altered environmental conditions. Yet, recent studies have shown that changes in metabolic fluxes can also trigger phenotypic changes even when environmental conditions are unchanged. This suggests that cells have mechanisms in place to assess the magnitude of metabolic fluxes, that is, the rate of metabolic reactions, and use this information to regulate their physiology. In this review, we describe recent evidence for metabolic flux-sensing and flux-dependent regulation. Furthermore, we discuss how such sensing and regulation can be mechanistically achieved and present a set of new candidates for flux-signaling metabolites. Similar to metabolic-flux sensing, we argue that cells can also sense protein translation flux. Finally, we elaborate on the advantages that flux-based regulation can confer to cells. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

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.

FluxPyt: a Python-based free and open-source software for 13C-metabolic flux analyses.

Science.gov (United States)

Desai, Trunil S; Srivastava, Shireesh

2018-01-01

13 C-Metabolic flux analysis (MFA) is a powerful approach to estimate intracellular reaction rates which could be used in strain analysis and design. Processing and analysis of labeling data for calculation of fluxes and associated statistics is an essential part of MFA. However, various software currently available for data analysis employ proprietary platforms and thus limit accessibility. We developed FluxPyt, a Python-based truly open-source software package for conducting stationary 13 C-MFA data analysis. The software is based on the efficient elementary metabolite unit framework. The standard deviations in the calculated fluxes are estimated using the Monte-Carlo analysis. FluxPyt also automatically creates flux maps based on a template for visualization of the MFA results. The flux distributions calculated by FluxPyt for two separate models: a small tricarboxylic acid cycle model and a larger Corynebacterium glutamicum model, were found to be in good agreement with those calculated by a previously published software. FluxPyt was tested in Microsoft™ Windows 7 and 10, as well as in Linux Mint 18.2. The availability of a free and open 13 C-MFA software that works in various operating systems will enable more researchers to perform 13 C-MFA and to further modify and develop the package.

Calving fluxes and basal melt rates of Antarctic ice shelves

NARCIS (Netherlands)

Depoorter, M.A.; Bamber, J.L.; Griggs, J.A.; Lenaerts, J.T.M.; Ligtenberg, S.R.M.; van den Broeke, M.R.; Moholdt, G.

2013-01-01

Iceberg calving has been assumed to be the dominant cause of mass loss for the Antarctic ice sheet, with previous estimates of the calving flux exceeding 2,000 gigatonnes per year1, 2. More recently, the importance of melting by the ocean has been demonstrated close to the grounding line and near

The Impact of the Applied Exchange Rate Regimes on the Internal Balance of Transition Countries

Directory of Open Access Journals (Sweden)

Vujanić Vlado

2017-12-01

Full Text Available One of the key goals of the economic policy makers of every country is to achieve internal and external balance. An unavoidable segment of the analysis concerning the achievement of internal and external balance is certainly the influence of the exchange rate regime applied in a country. European transition countries, despite their similar initial problems and final objectives, applied different exchange rate regimes adapted to the economic circumstances and needs of the country. The paper aims to examine and demonstrate the impact of the applied exchange rate regime on the internal balance of the transition countries. The research encompasses 10 representative transition countries, in the period from 2000-2014. The results of the research, from the aspect of internal balance, confirmed the justification of the application of the floating exchange rate regime in more developed, but not in less-developed, European transition countries. The application of floating exchange rate regimes in less-developed transition countries is associated with a considerably higher average inflation rate, which may be explained by the higher import dependence of lessdeveloped countries and by the consequent transfer of depreciation to price growth.

Effect of tunnel cross section on gas temperatures and heat fluxes in case of large heat release rate

International Nuclear Information System (INIS)

Fan, Chuan Gang; Li, Ying Zhen; Ingason, Haukur; Lönnermark, Anders

2016-01-01

Highlights: • The effect of tunnel cross section together with ventilation velocity was studied. • Ceiling temperature varies clearly with tunnel height, but little with tunnel width. • Downstream temperature decreases with increasing tunnel dimensions. • HRR is an important factor that influences decay rate of excess gas temperature. • An equation considering both tunnel dimensions and HRR was developed. - Abstract: Tests with liquid and solid fuels in model tunnels (1:20) were performed and analysed in order to study the effect of tunnel cross section (width and height) together with ventilation velocity on ceiling gas temperatures and heat fluxes. The model tunnel was 10 m long with varying width (0.3 m, 0.45 m and 0.6 m) and height (0.25 m and 0.4 m). Test results show that the maximum temperature under the ceiling is a weak function of heat release rate (HRR) and ventilation velocity for cases with HRR more than 100 MW at full scale. It clearly varies with the tunnel height and is a weak function of the tunnel width. With a lower tunnel height, the ceiling is closer to the base of continuous flame zone and the temperatures become higher. Overall, the gas temperature beneath the ceiling decreases with the increasing tunnel dimensions, and increases with the increasing longitudinal ventilation velocity. The HRR is also an important factor that influences the decay rate of excess gas temperature, and a dimensionless HRR integrating HRR and other two key parameters, tunnel cross-sectional area and distance between fuel centre and tunnel ceiling, was introduced to account for the effect. An equation for the decay rate of excess gas temperature, considering both the tunnel dimensions and HRR, was developed. Moreover, a larger tunnel cross-sectional area will lead to a smaller heat flux.

An introduction to the Australian and New Zealand flux tower network - OzFlux

Science.gov (United States)

Beringer, Jason; Hutley, Lindsay B.; McHugh, Ian; Arndt, Stefan K.; Campbell, David; Cleugh, Helen A.; Cleverly, James; Resco de Dios, Víctor; Eamus, Derek; Evans, Bradley; Ewenz, Cacilia; Grace, Peter; Griebel, Anne; Haverd, Vanessa; Hinko-Najera, Nina; Huete, Alfredo; Isaac, Peter; Kanniah, Kasturi; Leuning, Ray; Liddell, Michael J.; Macfarlane, Craig; Meyer, Wayne; Moore, Caitlin; Pendall, Elise; Phillips, Alison; Phillips, Rebecca L.; Prober, Suzanne M.; Restrepo-Coupe, Natalia; Rutledge, Susanna; Schroder, Ivan; Silberstein, Richard; Southall, Patricia; Yee, Mei Sun; Tapper, Nigel J.; van Gorsel, Eva; Vote, Camilla; Walker, Jeff; Wardlaw, Tim

2016-10-01

OzFlux is the regional Australian and New Zealand flux tower network that aims to provide a continental-scale national research facility to monitor and assess trends, and improve predictions, of Australia's terrestrial biosphere and climate. This paper describes the evolution, design, and current status of OzFlux as well as provides an overview of data processing. We analyse measurements from all sites within the Australian portion of the OzFlux network and two sites from New Zealand. The response of the Australian biomes to climate was largely consistent with global studies except that Australian systems had a lower ecosystem water-use efficiency. Australian semi-arid/arid ecosystems are important because of their huge extent (70 %) and they have evolved with common moisture limitations. We also found that Australian ecosystems had a similar radiation-use efficiency per unit leaf area compared to global values that indicates a convergence toward a similar biochemical efficiency. The two New Zealand sites represented extremes in productivity for a moist temperate climate zone, with the grazed dairy farm site having the highest GPP of any OzFlux site (2620 gC m-2 yr-1) and the natural raised peat bog site having a very low GPP (820 gC m-2 yr-1). The paper discusses the utility of the flux data and the synergies between flux, remote sensing, and modelling. Lastly, the paper looks ahead at the future direction of the network and concludes that there has been a substantial contribution by OzFlux, and considerable opportunities remain to further advance our understanding of ecosystem response to disturbances, including drought, fire, land-use and land-cover change, land management, and climate change, which are relevant both nationally and internationally. It is suggested that a synergistic approach is required to address all of the spatial, ecological, human, and cultural challenges of managing the delicately balanced ecosystems in Australasia.

Internal transport barrier triggering by rational magnetic flux surfaces in tokamaks

International Nuclear Information System (INIS)

Joffrin, E.; Challis, C.D.; Conway, G.D.

2003-01-01

The formation of Internal Transport Barriers (ITBs) has been experimentally associated with the presence of rational q-surfaces in both JET and ASDEX Upgrade. The triggering mechanisms are related to the occurrence of magneto-hydrodynamic (MHD) instabilities such as mode coupling or fishbone activity. These events could locally modify the poloidal velocity and increase transiently the shearing rate to values comparable to the linear growth rate of ITG modes. For JET reversed magnetic shear scenarios, ITB emergence occurs preferentially when the minimum q reaches an integer value. In this case, transport effects localised in the vicinity of zero magnetic shear and close to rational q values may also contribute to the formation of ITBs.The role of rational q surfaces on ITB triggering stresses the importance of q profile control for advanced tokamak scenario and could contribute to lower substantially the access power to these scenarios in next step facilities. (author)

Internal Transport Barrier triggering by rational magnetic flux surfaces in tokamaks

International Nuclear Information System (INIS)

Joffrin, E.H.

2002-01-01

The formation of Internal Transport Barriers (ITBs) has been experimentally associated with the presence of rational q-surfaces in both JET and ASDEX Upgrade. The triggering mechanisms are related to the occurrence of magneto-hydrodynamic (MHD) instabilities such as mode coupling or fishbone activity. These events could locally modify the poloidal velocity and increase transiently the shearing rate to values comparable to the linear growth rate of ITG modes. For reversed magnetic shear scenario, ITB emergence occurs preferentially when the minimum q reaches an integer value. In this case, transport effects localised in the vicinity of zero magnetic shear and close to rational q values may also contribute to the formation of ITBs. The role of rational q surfaces on ITB triggering stresses the importance of q profile control for advanced tokamak scenario and could contribute to lower substantially the access power to these scenarios in next step facilities. (author)

Validation of absolute axial neutron flux distribution calculations with MCNP with 197Au(n,γ)198Au reaction rate distribution measurements at the JSI TRIGA Mark II reactor.

Science.gov (United States)

Radulović, Vladimir; Štancar, Žiga; Snoj, Luka; Trkov, Andrej

2014-02-01

The calculation of axial neutron flux distributions with the MCNP code at the JSI TRIGA Mark II reactor has been validated with experimental measurements of the (197)Au(n,γ)(198)Au reaction rate. The calculated absolute reaction rate values, scaled according to the reactor power and corrected for the flux redistribution effect, are in good agreement with the experimental results. The effect of different cross-section libraries on the calculations has been investigated and shown to be minor. Copyright © 2013 Elsevier Ltd. All rights reserved.

Flight muscle enzymes and metabolic flux rates during hovering flight of the nectar bat, Glossophaga soricina: further evidence of convergence with hummingbirds.

Science.gov (United States)

Suarez, R K; Welch, K C; Hanna, S K; Herrera M, L G

2009-06-01

Given their high metabolic rates, nectarivorous diet, and ability to directly fuel their energetically-expensive flight using recently-ingested sugar, we tested the hypothesis that Pallas long tongued nectar bats (Glossophaga soricina) possess flight muscles similar to those of hummingbirds with respect to enzymatic flux capacities in bioenergetic pathways. In addition, we compared these biochemical capacities with flux rates achieved in vivo during hovering flight. Rates of oxygen consumption (V(O(2))) were measured during hover-feeding and used to estimate rates of ATP turnover, glucose and long-chain fatty acid oxidation per unit mass of flight muscle. Enzyme V(max) values at key steps in glucose and fatty acid oxidation obtained in vitro from pectoralis muscle samples exceed those found in the locomotory muscles of other species of small mammals and resemble data obtained from hummingbird flight muscles. The ability of nectar bats and hummingbirds to hover in fed and fasted states, fueled almost exclusively by carbohydrate or fat, respectively, allowed the estimation of fractional velocities (v/V(max)) at both the hexokinase and carnitine palmitoyltransferase-2 steps in glucose and fatty acid oxidation, respectively. The results further support the hypothesis of convergent evolution in biochemical and physiological traits in nectar bats and hummingbirds.

Lymph flux rates from various lymph sacs in the cane toad Rhinella marina: an experimental evaluation of the roles of compliance, skeletal muscles and the lungs in the movement of lymph.

Science.gov (United States)

Hillman, Stanley S; Hedrick, Michael S; Drewes, Robert C; Withers, Philip C

2010-09-15

A new method for quantitatively determining lymph flux from various lymphatic sacs of an anuran, the cane toad, was developed. This method used the dye dilution principle of C(i)V(i)=C(f)V(f) following injection of Evans Blue into specific lymph sacs and measuring its appearance in the venous circulation. The apparent lymph volume was 57 ml kg(-1). The greatest rate of lymph return (0.5-0.8 ml kg(-1) min(-1)) and best linear fit of Evans Blue appearance in the circulation with time followed injections into the subvertebral lymph sac, which has direct connections to both the anterior and posterior pairs of lymphatic hearts. Rate of lymph flux from the pair of posterior lymph hearts was three times greater than the anterior pair. Rates of lymph flux were only influenced by injection volume in the crural lymph sacs, implicating lymph sac compliance as the source of the pressure for lymph movement from these sacs. Femoral lymph sac fluxes were decreased by 60% following ablation of the tendons of the sphincter ani cloacalis, abdominal crenators and piriformis. This supports a role for these muscles in generating the pressure for vertical lymph movement. Femoral lymph sac fluxes were also decreased by 70% by the insertion of a coil in the subvertebral lymph sac, preventing normal compression and expansion of this sac by the lungs. This supports a role for lung ventilation in generating the pressure for vertical movement of lymph. Contrary to previous hypotheses, fluxes from the brachial sac were not influenced by insertion of the coil into the subvertebral sac. A haemorrhage equivalent to 50% of the blood volume did not change lymph flux rates from the femoral lymph sacs. These data provide the first experimental evidence that actual lymph fluxes in the cane toad Rhinella marina depend on lymph sac compliance, contraction of specific skeletal muscles and lung ventilation to move lymph laterally and vertically to the dorsally located lymphatic hearts.

Flux Recovery of a Forward Osmosis Membrane After a Fouling Process

Science.gov (United States)

Romero-Mangado, Jaione; Parodi, Jurek; Gamboa-Vazquez, Sonia; Stefanson, Ofir; Diaz-Cartagena, Diana C.; Flynn, Michael

2016-01-01

Wastewater treatment through forward osmosis (FO) membranes is a process that has been evaluated in the past years as an innovative technology for the Next Generation Life Support Systems. FO technologies are cost effective, and require very low energy consumption, but are subject to membrane fouling. Membrane fouling occurs when unwanted materials accumulate on the active side of the membrane during the wastewater treatment process, which leads to a decrease in membrane flux rate. The aim of this study is to identify the materials that cause flux rate reduction due to membrane fouling, as well as to evaluate the flux rate recovery after membrane treatment using commercially available antifoulants. Fourier Transform Infrared (FTIR) spectrometry results identified possible compounds that cause membrane fouling and FO testing results demonstrated flux rate recovery after membrane treatment using antifoulants.

Simulation of Silver Thin Films' Growth and Influence of Deposition Rate on Final Grain Size under Angle Flux and Standard Situation

Directory of Open Access Journals (Sweden)

Maryam Jamshidnejad

2011-01-01

Full Text Available In this paper, a 2D stimulation model, FACET, is used for investigation of the relation between micro structure and deposition conditions such as substrate temperature, deposition rate and deposition angle of Ag thin films. It is observed that by increasing the deposition rate in standard conditions providing that the temperature of substrate is low, the average of final grain size is decreased. While, in deposition with angle flux the average of final grain size is increased.

Abundant carbon substrates drive extremely high sulfate reduction rates and methane fluxes in Prairie Pothole Wetlands.

Science.gov (United States)

Dalcin Martins, Paula; Hoyt, David W; Bansal, Sheel; Mills, Christopher T; Tfaily, Malak; Tangen, Brian A; Finocchiaro, Raymond G; Johnston, Michael D; McAdams, Brandon C; Solensky, Matthew J; Smith, Garrett J; Chin, Yu-Ping; Wilkins, Michael J

2017-08-01

Inland waters are increasingly recognized as critical sites of methane emissions to the atmosphere, but the biogeochemical reactions driving such fluxes are less well understood. The Prairie Pothole Region (PPR) of North America is one of the largest wetland complexes in the world, containing millions of small, shallow wetlands. The sediment pore waters of PPR wetlands contain some of the highest concentrations of dissolved organic carbon (DOC) and sulfur species ever recorded in terrestrial aquatic environments. Using a suite of geochemical and microbiological analyses, we measured the impact of sedimentary carbon and sulfur transformations in these wetlands on methane fluxes to the atmosphere. This research represents the first study of coupled geochemistry and microbiology within the PPR and demonstrates how the conversion of abundant labile DOC pools into methane results in some of the highest fluxes of this greenhouse gas to the atmosphere ever reported. Abundant DOC and sulfate additionally supported some of the highest sulfate reduction rates ever measured in terrestrial aquatic environments, which we infer to account for a large fraction of carbon mineralization in this system. Methane accumulations in zones of active sulfate reduction may be due to either the transport of free methane gas from deeper locations or the co-occurrence of methanogenesis and sulfate reduction. If both respiratory processes are concurrent, any competitive inhibition of methanogenesis by sulfate-reducing bacteria may be lessened by the presence of large labile DOC pools that yield noncompetitive substrates such as methanol. Our results reveal some of the underlying mechanisms that make PPR wetlands biogeochemical hotspots, which ultimately leads to their critical, but poorly recognized role in regional greenhouse gas emissions. © 2017 John Wiley & Sons Ltd.

Abundant carbon substrates drive extremely high sulfate reduction rates and methane fluxes in Prairie Pothole Wetlands

Energy Technology Data Exchange (ETDEWEB)

Dalcin Martins, Paula [Microbiology Department, The Ohio State University, Columbus OH 43210 USA; Hoyt, David W. [Environmental Molecular Sciences Laboratory, Richland WA 99350 USA; Bansal, Sheel [United States Geological Survey - Northern Prairie Wildlife Research Center, Jamestown ND 58401 USA; Mills, Christopher T. [United States Geological Survey, Crustal Geophysics and Geochemistry Science Center, Building 20, Denver Federal Center Denver CO 80225 USA; Tfaily, Malak [Environmental Molecular Sciences Laboratory, Richland WA 99350 USA; Tangen, Brian A. [United States Geological Survey - Northern Prairie Wildlife Research Center, Jamestown ND 58401 USA; Finocchiaro, Raymond G. [United States Geological Survey - Northern Prairie Wildlife Research Center, Jamestown ND 58401 USA; Johnston, Michael D. [School of Earth Sciences, The Ohio State University, Columbus OH 43210 USA; McAdams, Brandon C. [School of Earth Sciences, The Ohio State University, Columbus OH 43210 USA; Solensky, Matthew J. [United States Geological Survey - Northern Prairie Wildlife Research Center, Jamestown ND 58401 USA; Smith, Garrett J. [Microbiology Department, The Ohio State University, Columbus OH 43210 USA; Chin, Yu-Ping [School of Earth Sciences, The Ohio State University, Columbus OH 43210 USA; Wilkins, Michael J. [Microbiology Department, The Ohio State University, Columbus OH 43210 USA; School of Earth Sciences, The Ohio State University, Columbus OH 43210 USA

2017-02-23

Inland waters are increasingly recognized as critical sites of methane emissions to the atmosphere, but the biogeochemical reactions driving such fluxes are less well understood. The Prairie Pothole Region (PPR) of North America is one of the largest wetland complexes in the world, containing millions of small, shallow wetlands. The sediment pore waters of PPR wetlands contain some of the highest concentrations of dissolved organic carbon (DOC) and sulfur species ever recorded in terrestrial aquatic environments. Using a suite of geochemical and microbiological analyses we measured the impact of sedimentary carbon and sulfur transformations in these wetlands on methane fluxes to the atmosphere. This research represents the first study of coupled geochemistry and microbiology within the PPR, and demonstrates how the conversion of abundant labile DOC pools into methane results in some of the highest fluxes of this greenhouse gas to the atmosphere ever reported. Abundant DOC and sulfate additionally supported some of the highest sulfate reduction rates ever measured in terrestrial aquatic environments, which we infer to account for a large fraction of carbon mineralization in this system. Methane accumulations in zones of active sulfate reduction may be due to either the transport of free methane gas from deeper locations, or the co-occurrence of methanogenesis and sulfate reduction. If both respiratory processes are concurrent, any competitive inhibition of methanogenesis by sulfate-reducing bacteria may be lessened by the presence of large labile DOC pools that yield non-competitive substrates such as methanol. Our results reveal some of the underlying mechanisms that make PPR wetlands biogeochemical hotspots, which ultimately leads to their critical, but poorly recognized role in regional greenhouse gas emissions.

Exchange rate pass-through and the role of international distribution channels

OpenAIRE

Desiraju, Ramarao; Shrikhande, Milind

1996-01-01

Manufacturers selling in foreign markets often do not completely pass on the effects of fluctuations in exchange rates to the prices of their products. Our paper addresses this puzzle and studies the effects of the international distribution channel on exchange rate pass-through. We develop an exchange rate pass-through model that takes into account the role of an intermediary between a domestic manufacturer and its consumers in a foreign market. We find that the magnitude of the pass-through...

Assessment of breathing rate of adult Korean for use in internal dosimetry

International Nuclear Information System (INIS)

Kim, J.I.; Lee, Y.J.; Jin, Y.W.; Kim, C.S.; Lee, J.K.

2003-01-01

Breathing rate is one of the key factors in evaluating doses due to inhalation of airborne radionuclides. Since the reference values of breathing rate provided by the International Commission on Radiological Protection (ICRP) are based on the physiology of Caucasian, they are not necessarily appropriate for internal dosimetry for Korean. In this study, we assessed breathing rate of Korean by measuring the forced vital capacity (FVC), the forced expiratory volume in second (FEV1) and the minute ventilation(MV). Measurements were made using SP-1 spirometry unit (Schiller AG. 1998) for 1474 adult Koreans whose heights and weights are in the range of one standard deviation from the mean values. The total liters of air breathed for working and resting were evaluated after the ICRP approach. We also considered smoking and ailment in the lungs. The resulting breathing rate appears to be 2.3x10 4 L/day which well agrees with the value given in ICRP 23

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

An alternative method for the measurement of neutron flux

Indian Academy of Sciences (India)

A simple and easy method for measuring the neutron flux is presented. This paper deals with the experimental verification of neutron dose rate–flux relationship for a non-dissipative medium. Though the neutron flux cannot be obtained from the dose rate in a dissipative medium, experimental result shows that for ...

Correlations Between Ratings on the Resident Annual Evaluation Summary and the Internal Medicine Milestones and Association With ABIM Certification Examination Scores Among US Internal Medicine Residents, 2013-2014.

Science.gov (United States)

Hauer, Karen E; Vandergrift, Jonathan; Hess, Brian; Lipner, Rebecca S; Holmboe, Eric S; Hood, Sarah; Iobst, William; Hamstra, Stanley J; McDonald, Furman S

2016-12-06

US internal medicine residency programs are now required to rate residents using milestones. Evidence of validity of milestone ratings is needed. To compare ratings of internal medicine residents using the pre-2015 resident annual evaluation summary (RAES), a nondevelopmental rating scale, with developmental milestone ratings. Cross-sectional study of US internal medicine residency programs in the 2013-2014 academic year, including 21 284 internal medicine residents (7048 postgraduate-year 1 [PGY-1], 7233 PGY-2, and 7003 PGY-3). Program director ratings on the RAES and milestone ratings. Correlations of RAES and milestone ratings by training year; correlations of medical knowledge ratings with American Board of Internal Medicine (ABIM) certification examination scores; rating of unprofessional behavior using the 2 systems. Corresponding RAES ratings and milestone ratings showed progressively higher correlations across training years, ranging among competencies from 0.31 (95% CI, 0.29 to 0.33) to 0.35 (95% CI, 0.33 to 0.37) for PGY-1 residents to 0.43 (95% CI, 0.41 to 0.45) to 0.52 (95% CI, 0.50 to 0.54) for PGY-3 residents (all P values internal medicine residents in the 2013-2014 academic year, milestone-based ratings correlated with RAES ratings but with a greater difference across training years. Both rating systems for medical knowledge correlated with ABIM certification examination scores. Milestone ratings may better detect problems with professionalism. These preliminary findings may inform establishment of the validity of milestone-based assessment.

Hydrothermal element fluxes from Copahue, Argentina: A “beehive” volcano in turmoil

Science.gov (United States)

Varekamp, Johan C.; Ouimette, Andrew P.; Herman, Scott W.; Bermúdez, Adriana; Delpino, Daniel

2001-11-01

Copahue volcano erupted altered rock debris, siliceous dust, pyroclastic sulfur, and rare juvenile fragments between 1992 and 1995, and magmatic eruptions occurred in July October 2000. Prior to 2000, the Copahue crater lake, acid hot springs, and rivers carried acid brines with compositions that reflected close to congruent rock dissolution. The ratio between rock-forming elements and chloride in the central zone of the volcano-hydrothermal system has diminished over the past few years, reflecting increased water/rock ratios as a result of progressive rock dissolution. Magmatic activity in 2000 provided fresh rocks for the acid fluids, resulting in higher ratios between rock-forming elements and chloride in the fluids and enhanced Mg fluxes. The higher Mg fluxes started several weeks prior to the eruption. Model data on the crater lake and river element flux determinations indicate that Copahue volcano was hollowed out at a rate of about 20000 25000 m3/yr, but that void space was filled with about equal amounts of silica and liquid elemental sulfur. The extensive rock dissolution has weakened the internal volcanic structure, making flank collapse a volcanic hazard at Copahue.

Characterization of high flux magnetized helium plasma in SCU-PSI linear device

Science.gov (United States)

Xiaochun, MA; Xiaogang, CAO; Lei, HAN; Zhiyan, ZHANG; Jianjun, WEI; Fujun, GOU

2018-02-01

A high-flux linear plasma device in Sichuan University plasma-surface interaction (SCU-PSI) based on a cascaded arc source has been established to simulate the interactions between helium and hydrogen plasma with the plasma-facing components in fusion reactors. In this paper, the helium plasma has been characterized by a double-pin Langmuir probe. The results show that the stable helium plasma beam with a diameter of 26 mm was constrained very well at a magnetic field strength of 0.3 T. The core density and ion flux of helium plasma have a strong dependence on the applied current, magnetic field strength and gas flow rate. It could reach an electron density of 1.2 × 1019 m-3 and helium ion flux of 3.2 × 1022 m-2 s-1, with a gas flow rate of 4 standard liter per minute, magnetic field strength of 0.2 T and input power of 11 kW. With the addition of -80 V applied to the target to increase the helium ion energy and the exposure time of 2 h, the flat top temperature reached about 530 °C. The different sizes of nanostructured fuzz on irradiated tungsten and molybdenum samples surfaces under the bombardment of helium ions were observed by scanning electron microscopy. These results measured in the SCU-PSI linear device provide a reference for International Thermonuclear Experimental Reactor related PSI research.

Internal transport barrier triggering by rational magnetic flux surfaces in tokamaks

International Nuclear Information System (INIS)

Joffrin, E.; Challis, C.D.; Conway, G.D.

2003-01-01

The formation of internal transport barriers (ITBs) has been experimentally associated with the presence of rational q surfaces in both JET and ASDEX Upgrade. The triggering mechanisms are related to the occurrence of magneto-hydrodynamic (MHD) instabilities such as mode coupling and fishbone activity. These events could locally modify the poloidal velocity and increase transiently the shearing rate to values comparable with the linear growth rate of ion temperature gradient modes. For JET reversed magnetic shear scenarios, ITB emergence occurs preferentially when the minimum q reaches an integral value. In this case, transport effects localized in the vicinity of zero magnetic shear and close to rational q values may be at the origin of ITB formation. The role of rational q surfaces in ITB triggering stresses the importance of q profile control for an advanced tokamak scenario and could assist in substantially lowering the access power to these scenarios in next step facilities. (author)

Divertor Heat Flux Reduction and Detachment in the National Spherical Torus eXperiment.

Science.gov (United States)

Soukhanovskii, Vsevolod

2007-11-01

Steady-state handling of the heat flux is a critical divertor issue for both the International Thermonuclear Experimental Reactor and spherical torus (ST) devices. Because of an inherently compact divertor, it was thought that ST-based devices might not be able to fully utilize radiative and dissipative divertor techniques based on induced power and momentum loss. However, initial experiments conducted in the National Spherical Torus Experiment in an open geometry horizontal carbon plate divertor using 0.8 MA 2-6 MW NBI-heated lower single null H-mode plasmas at the lower end of elongations κ=1.8-2.4 and triangularities δ=0.45-0.75 demonstrated that high divertor peak heat fluxes, up to 6-10 MW/ m^2, could be reduced by 50-75% using a high-recycling radiative divertor regime with D2 injection. Furthermore, similar reduction was obtained with a partially detached divertor (PDD) at high D2 injection rates, however, it was accompanied by an X-point MARFE that quickly led to confinement degradation. Another approach takes advantage of the ST relation between strong shaping and high performance, and utilizes the poloidal magnetic flux expansion in the divertor region. Up to 60 % reduction in divertor peak heat flux was achieved at similar levels of scrape-off layer power by varying plasma shaping and thereby increasing the outer strike point (OSP) poloidal flux expansion from 4-6 to 18-22. In recent experiments conducted in highly-shaped 1.0-1.2 MA 6 MW NBI heated H-mode plasmas with divertor D2 injection at rates up to 10^22 s-1, a PDD regime with OSP peak heat flux 0.5-1.5 MW/m^2 was obtained without noticeable confinement degradation. Calculations based on a two point scrape-off layer model with parameterized power and momentum losses show that the short parallel connection length at the OSP sets the upper limit on the radiative exhaust channel, and both the impurity radiation and large momentum sink achievable only at high divertor neutral pressures are required

Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames.

Science.gov (United States)

Singh, Ajay V; Gollner, Michael J

2016-06-01

Modeling the realistic burning behavior of condensed-phase fuels has remained out of reach, in part because of an inability to resolve the complex interactions occurring at the interface between gas-phase flames and condensed-phase fuels. The current research provides a technique to explore the dynamic relationship between a combustible condensed fuel surface and gas-phase flames in laminar boundary layers. Experiments have previously been conducted in both forced and free convective environments over both solid and liquid fuels. A unique methodology, based on the Reynolds Analogy, was used to estimate local mass burning rates and flame heat fluxes for these laminar boundary layer diffusion flames utilizing local temperature gradients at the fuel surface. Local mass burning rates and convective and radiative heat feedback from the flames were measured in both the pyrolysis and plume regions by using temperature gradients mapped near the wall by a two-axis traverse system. These experiments are time-consuming and can be challenging to design as the condensed fuel surface burns steadily for only a limited period of time following ignition. The temperature profiles near the fuel surface need to be mapped during steady burning of a condensed fuel surface at a very high spatial resolution in order to capture reasonable estimates of local temperature gradients. Careful corrections for radiative heat losses from the thermocouples are also essential for accurate measurements. For these reasons, the whole experimental setup needs to be automated with a computer-controlled traverse mechanism, eliminating most errors due to positioning of a micro-thermocouple. An outline of steps to reproducibly capture near-wall temperature gradients and use them to assess local burning rates and heat fluxes is provided.

Research on the trend of Yen exchange rate and international crude oil price fluctuation affected by Japan’s earthquake

Directory of Open Access Journals (Sweden)

Xiaoguang Li

2014-05-01

Full Text Available Purpose: Whether this earthquake would become a turning point of the high oil price and whether it would have big impact on yen exchange rate are two issues to be discussed in this paper.Design/methodology/approach: To analyze deeply the internal relations between changes in yen exchange rate caused by Japan’s earthquake and price fluctuation of international crude oil, this research chooses middle rate of yen exchange rate during the 45 days around Japan’s earthquake and price data of international crude oil to do an empirical study, uses VAR model and HP trend decomposition to estimate the mutual effect of yen exchange rate change and price fluctuation of international crude oil in this period.Findings: It has been found in the empirical study with VAR model and HP filter decomposition model on the yen exchange rate and the international crude oil price fluctuation during 45 days around Japan’s earthquake that: the fluctuation of yen exchange rate around the earthquake is one of the main reasons for the drastic fluctuation of international crude oil price in that period. The fluctuation of international crude oil price directly triggered by yen exchange rate occupies 13.54% of its total variance. There is a long-term interactive relationship between yen exchange rate and international crude oil price. The upward trend of international crude oil price after the earthquake was obvious, while yen exchange rate remained relatively stable after the earthquake.Originality/value: As economic globalization goes deeper, the influence of natural disasters on international financial market and world economy will become more and more obvious. It has a great revelatory meaning to studying further each kind of natural disaster’s impacts on international financial market and world economics.

Hydrogen sulfide flux measurements from construction and demolition debris (C&D) landfills.

Science.gov (United States)

Eun, Sangho; Reinhart, Debra R; Cooper, C David; Townsend, Timothy G; Faour, Ayman

2007-01-01

Hydrogen sulfide (H2S) has been identified as a principal odorous component of gaseous emissions from construction and demolition debris (C&D) landfills. Although several studies have reported the ambient concentrations of H2S near C&D landfills, few studies have quantified emission rates of H2S. One of the most widely used techniques for measuring surface gas emission rates from landfills is the flux chamber method. Flux measurements using the flux chamber were performed at five different C&D landfills from April to August, 2003. The flux rates of H2S measured in this research were between 0.192 and 1.76 mg/(m2-d).

Powder Flux Regulation in the Laser Material Deposition Process

Science.gov (United States)

Arrizubieta, Jon Iñaki; Wegener, Maximiliam; Arntz, Kristian; Lamikiz, Aitzol; Ruiz, Jose Exequiel

In the present research work a powder flux regulation system has been designed, developed and validated with the aim of improving the Laser Material Deposition (LMD) process. In this process, the amount of deposited material per substrate surface unit area depends on the real feed rate of the nozzle. Therefore, a regulation system based on a solenoid valve has been installed at the nozzle entrance in order to control the powder flux. The powder flux control has been performed based on the machine real feed rate, which is compared with the programmed feed rate. An instantaneous velocity error is calculated and the powder flow is controlled as a function of this variation using Pulse Width Modulation (PWM) signals. Thereby, in zones where the Laser Material Deposition machine reduces the feed rate due to a trajectory change, powder accumulation can be avoided and the generated clads would present a homogeneous shape.

Advances in the Surface Renewal Flux Measurement Method

Science.gov (United States)

Shapland, T. M.; McElrone, A.; Paw U, K. T.; Snyder, R. L.

2011-12-01

The measurement of ecosystem-scale energy and mass fluxes between the planetary surface and the atmosphere is crucial for understanding geophysical processes. Surface renewal is a flux measurement technique based on analyzing the turbulent coherent structures that interact with the surface. It is a less expensive technique because it does not require fast-response velocity measurements, but only a fast-response scalar measurement. It is therefore also a useful tool for the study of the global cycling of trace gases. Currently, surface renewal requires calibration against another flux measurement technique, such as eddy covariance, to account for the linear bias of its measurements. We present two advances in the surface renewal theory and methodology that bring the technique closer to becoming a fully independent flux measurement method. The first advance develops the theory of turbulent coherent structure transport associated with the different scales of coherent structures. A novel method was developed for identifying the scalar change rate within structures at different scales. Our results suggest that for canopies less than one meter in height, the second smallest coherent structure scale dominates the energy and mass flux process. Using the method for resolving the scalar exchange rate of the second smallest coherent structure scale, calibration is unnecessary for surface renewal measurements over short canopies. This study forms the foundation for analysis over more complex surfaces. The second advance is a sensor frequency response correction for measuring the sensible heat flux via surface renewal. Inexpensive fine-wire thermocouples are frequently used to record high frequency temperature data in the surface renewal technique. The sensible heat flux is used in conjunction with net radiation and ground heat flux measurements to determine the latent heat flux as the energy balance residual. The robust thermocouples commonly used in field experiments

The submm wave Josephson flux flow oscillator; Linewidth measurements and simple theory

DEFF Research Database (Denmark)

Mygind, Jesper; Koshelets, V. P.; Samuelsen, Mogens Rugholm

2005-01-01

The Flux Flow Oscillator (FFO) is a long Josephson junction in which a DC bias current and a DC magnetic field maintain a unidirectional viscous flow of magnetic flux quanta. The theoretical linewidth of the electromagnetic radiation generated at the end boundary is due to internal current...

The influence of plasma horizontal position on the neutron rate and flux of neutral atoms in injection heating experiment on the TUMAN-3M tokamak

Science.gov (United States)

Kornev, V. A.; Chernyshev, F. V.; Melnik, A. D.; Askinazi, L. G.; Wagner, F.; Vildjunas, M. I.; Zhubr, N. A.; Krikunov, S. V.; Lebedev, S. V.; Razumenko, D. V.; Tukachinsky, A. S.

2013-11-01

Horizontal displacement of plasma along the major radius has been found to significantly influence the fluxes of 2.45 MeV DD neutrons and high-energy charge-exchange atoms from neutral beam injection (NBI) heated plasma of the TUMAN-3M tokamak. An inward shift by Δ R = 1 cm causes 1.2-fold increase in the neutron flux and 1.9-fold increase in the charge-exchange atom flux. The observed increase in the neutron flux is attributed to joint action of several factors-in particular, improved high-energy ion capture and confinement and, probably, decreased impurity inflow from the walls, which leads to an increase in the density of target ions. A considerable increase in the flux of charge-exchange neutrals in inward-shifted plasma is due to the increased number of captured high-energy ions and, to some extent, the increased density of the neutral target. As a result of the increase in the content of high-energy ions, the central ion temperature T i (0) increased from 250 to 350 eV. The dependence of the neutron rate on major radius R 0 should be taken into account when designing compact tokamak-based neutron sources.

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

Reduced flux motion via flux creep annealing in high- Jc single-crystal Y1Ba2Cu3O7

International Nuclear Information System (INIS)

Thompson, J.R.; Sun, Y.R.; Malozemoff, A.P.; Christen, D.K.; Kerchner, H.R.; Ossandon, J.G.; Marwick, A.D.; Holtzberg, F.

1991-01-01

We investigated the stabilization of magnetic flux in a high-temperature superconductor (a proton-irradiated Y 1 Ba 2 Cu 3 O 7 crystal), by operating with subcritical current density J. Using the thermal history to obtain an induced current density J≤J c , we observed a drastically reduced relaxation rate dM/dt (M=magnetization), after ''flux creep annealing.'' The results show that the field gradient ∼J∼M determined the relaxation rate, independent of the sample's H-T history, in agreement with recent theory

78 FR 1277 - International Product Change-Global Expedited Package Services-Non-Published Rates

Science.gov (United States)

2013-01-08

... POSTAL SERVICE International Product Change--Global Expedited Package Services-- Non-Published...-- Non-Published Rates 4 (GEPS-NPR 4) to the Competitive Products List. DATES: Effective date: January 8... add Global Expedited Package Services-- Non-Published Rates 4 (GEPS-NPR 4) to the Competitive Products...

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.)

Internal Flow of Contra-Rotating Small Hydroturbine at Off- Design Flow Rates

Science.gov (United States)

SHIGEMITSU, Toru; TAKESHIMA, Yasutoshi; OGAWA, Yuya; FUKUTOMI, Junichiro

2016-11-01

Small hydropower generation is one of important alternative energy, and enormous potential lie in the small hydropower. However, efficiency of small hydroturbines is lower than that of large one. Then, there are demands for small hydroturbines to keep high performance in wide flow rate range. Therefore, we adopted contra-rotating rotors, which can be expected to achieve high performance. In this research, performance of the contra-rotating small hydroturbine with 60mm casing diameter was investigated by an experiment and numerical analysis. Efficiency of the contra-rotating small hydroturbine was high in pico-hydroturbine and high efficiency could be kept in wide flow rate range, however the performance of a rear rotor decreased significantly in partial flow rates. Then, internal flow condition, which was difficult to measure experimentally, was investigated by the numerical flow analysis. Then, a relation between the performance and internal flow condition was considered by the numerical analysis result.

A trigger mechanism for the emerging flux model of solar flares

International Nuclear Information System (INIS)

Tur, T.J.; Priest, E.R.

1978-01-01

The energetics of a current sheet that forms between newly emerging flux and an ambient field are considered. As more and more flux emerges, so the sheet rises in the solar atmosphere. The various contributions to the thermal energy balance in the sheet approximated and the resulting equation solved for the internal temperature of the sheet. It is found that, for certain choices of the ambient magnetic field strength and velocity, the internal temperature increases until, when the sheet reaches some critical height, no neighbouring equilibrium state exists. The temperature than increases rapidly, seeking a hotter branch of the solution curve. During this dynamic heating the threshold temperature for the onset of plasma microinstabilities may be attained. It is suggested that this may be a suitable trigger mechanism for the recently proposed 'emerging flux' model of a solar flare. (Auth.)

Recycling flow rate control device in BWR type reactor

International Nuclear Information System (INIS)

Fujiwara, Tadashi; Koda, Yasushi

1988-01-01

Purpose: To reduce the recycling pump speed if the pressure variation width and the variation ratio in the nuclear reactor exceed predetermined values, to thereby avoid the shutdown of the plant. Constitution: There has been proposed a method of monitoring the neutron flux increase thereby avoiding unnecessary plant shutdown, but it involves a problems of reactor scram depending on the state of the plant and the set values. In view of the above, in the plant using internal pumps put under the thyristor control and having high response to recycling flow rate, the reactor pressure is monitored and the speed of the internal pump is rapidly reduced when the pressure variation width and variation ratio exceed predetermined values to reduce the reactor power and avoid the plant shutdown. This can reduce the possibility of unnecessary power reduction due to neutron flux noises or the possibility of plant shutdown under low power conditions. Further, since the reactor operation can be continued without stopping the recycling pump, the operation upon recovery can be made rapid. (Horiuchi, T.)

IFMIF High Flux Test Module-Recent progress in design and manufacturing

International Nuclear Information System (INIS)

Leichtle, D.; Arbeiter, F.; Dolensky, B.; Fischer, U.; Gordeev, S.; Heinzel, V.; Ihli, T.; Lang, K.-H.; Moeslang, A.; Simakov, S.P.; Slobodchuk, V.; Stratmanns, E.

2008-01-01

The International Fusion Material Irradiation Facility (IFMIF) is an accelerator driven neutron source for irradiation tests of candidate fusion reactor materials. Within the High Flux Test Module (HFTM) a testing volume of 0.5 l filled by qualified small scale specimens will be irradiated at displacement rates of 20-50 dpa/fpy in structural materials. The Forschungszentrum Karlsruhe (FZK) has developed a HFTM design which closely follows the design premise of maximising the space available for irradiation specimens in the IFMIF high flux zone and in addition allows keeping the temperature nearly constant in the rigs containing the specimen. Complementary analyses on nuclear, thermo-hydraulics and mechanical performance of the HFTM were performed to optimize the design. The present paper highlights the main design characteristics as well as recent progress achieved in this area. The contribution also includes (i) recommendations for the use of container, rig and capsule materials, and (ii) a description of the fabrication routes for the entire HFTM including brazing and filling procedures which are currently under development at the Forschungszentrum Karlsruhe

IFMIF High Flux Test Module-Recent progress in design and manufacturing

Energy Technology Data Exchange (ETDEWEB)

Leichtle, D. [Association FZK-EURATOM, Forschungszentrum Karlsruhe, Institut fuer Reaktorsicherheit, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)], E-mail: leichtle@irs.fzk.de; Arbeiter, F.; Dolensky, B.; Fischer, U.; Gordeev, S.; Heinzel, V.; Ihli, T.; Lang, K.-H. [Association FZK-EURATOM, Forschungszentrum Karlsruhe, Institut fuer Reaktorsicherheit, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Moeslang, A. [Association FZK-EURATOM, Forschungszentrum Karlsruhe, Institut fuer Materialforschung, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Simakov, S.P.; Slobodchuk, V.; Stratmanns, E. [Association FZK-EURATOM, Forschungszentrum Karlsruhe, Institut fuer Reaktorsicherheit, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

2008-12-15

The International Fusion Material Irradiation Facility (IFMIF) is an accelerator driven neutron source for irradiation tests of candidate fusion reactor materials. Within the High Flux Test Module (HFTM) a testing volume of 0.5 l filled by qualified small scale specimens will be irradiated at displacement rates of 20-50 dpa/fpy in structural materials. The Forschungszentrum Karlsruhe (FZK) has developed a HFTM design which closely follows the design premise of maximising the space available for irradiation specimens in the IFMIF high flux zone and in addition allows keeping the temperature nearly constant in the rigs containing the specimen. Complementary analyses on nuclear, thermo-hydraulics and mechanical performance of the HFTM were performed to optimize the design. The present paper highlights the main design characteristics as well as recent progress achieved in this area. The contribution also includes (i) recommendations for the use of container, rig and capsule materials, and (ii) a description of the fabrication routes for the entire HFTM including brazing and filling procedures which are currently under development at the Forschungszentrum Karlsruhe.

Aram Chaos and its constraints on the surface heat flux of Mars

NARCIS (Netherlands)

Schumacher, S.; Zegers, T.E.

2011-01-01

The surface heat flux of a planet is an important parameter to characterize its internal activity and to determine its thermal evolution. Here we report on a new method to constrain the surface heat flux of Mars during the Hesperian. For this, we explore the consequences for the martian surface

LOFT gamma densitometer background fluxes

International Nuclear Information System (INIS)

Grimesey, R.A.; McCracken, R.T.

1978-01-01

Background gamma-ray fluxes were calculated at the location of the γ densitometers without integral shielding at both the hot-leg and cold-leg primary piping locations. The principal sources for background radiation at the γ densitometers are 16 N activity from the primary piping H 2 O and γ radiation from reactor internal sources. The background radiation was calculated by the point-kernel codes QAD-BSA and QAD-P5A. Reasonable assumptions were required to convert the response functions calculated by point-kernel procedures into the gamma-ray spectrum from reactor internal sources. A brief summary of point-kernel equations and theory is included

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

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.

In situ measurement of mesopelagic particle sinking rates and the control of carbon transfer to the ocean interior during the Vertical Flux in the Global Ocean (VERTIGO) voyages in the North Pacific

Science.gov (United States)

Trull, T. W.; Bray, S. G.; Buesseler, K. O.; Lamborg, C. H.; Manganini, S.; Moy, C.; Valdes, J.

2008-07-01

Among the parameters affecting carbon transfer to the ocean interior, particle sinking rates vary three orders of magnitude and thus more than primary production, f-ratios, or particle carbon contents [e.g., Boyd, P.W., Trull, T.W., 2006. Understanding the export of marine biogenic particles: is there consensus? Progress in Oceanography 4, 276-312, doi:10.1016/j.pocean.2006.10.007]. Very few data have been obtained from the mesopelagic zone where the majority of carbon remineralization occurs and the attenuation of the sinking flux is determined. Here, we report sinking rates from ˜300 m depth for the subtropical (station ALOHA, June 2004) and subarctic (station K2, July 2005) North Pacific Ocean, obtained from short (6.5 day) deployments of an indented rotating sphere (IRS) sediment trap operating as an in situ settling column [Peterson, M.L., Wakeham, S.G., Lee, C., Askea, M.A., Miquel, J.C., 2005. Novel techniques for collection of sinking particles in the ocean and determining their settling rates. Limnology and Oceanography Methods 3, 520-532] to separate the flux into 11 sinking-rate fractions ranging from >820 to >2 m d -1 that are collected by a carousel for further analysis. Functioning of the IRS trap was tested using a novel programming sequence to check that all particles have cleared the settling column prior to the next delivery of particles by the 6-hourly rotation cycle of the IRS. There was some evidence (from the flux distribution among the cups and photomicroscopy of the collected particles) that very slow-sinking particles may have been under-collected because they were unable to penetrate the brine-filled collection cups, but good evidence for appropriate collection of fast-settling fractions. Approximately 50% of the particulate organic carbon (POC) flux was sinking at greater than 100 m d -1 at both stations. At ALOHA, more than 15% of the POC flux sank at >820 m d -1, but low fluxes make this uncertain, and precluded resolution of particles

Ballast minerals and the sinking carbon flux in the ocean: carbon-specific respiration rates and sinking velocity of marine snow aggregates

Directory of Open Access Journals (Sweden)

M. H. Iversen

2010-09-01

Full Text Available Recent observations have shown that fluxes of ballast minerals (calcium carbonate, opal, and lithogenic material and organic carbon fluxes are closely correlated in the bathypelagic zones of the ocean. Hence it has been hypothesized that incorporation of biogenic minerals within marine aggregates could either protect the organic matter from decomposition and/or increase the sinking velocity via ballasting of the aggregates. Here we present the first combined data on size, sinking velocity, carbon-specific respiration rate, and composition measured directly in three aggregate types; Emiliania huxleyi aggregates (carbonate ballasted, Skeletonema costatum aggregates (opal ballasted, and aggregates made from a mix of both E. huxleyi and S. costatum (carbonate and opal ballasted. Overall average carbon-specific respiration rate was ~0.13 d⁻¹ and did not vary with aggregate type and size. Ballasting from carbonate resulted in 2- to 2.5-fold higher sinking velocities than those of aggregates ballasted by opal. We compiled literature data on carbon-specific respiration rate and sinking velocity measured in aggregates of different composition and sources. Compiled carbon-specific respiration rates (including this study vary between 0.08 d⁻¹ and 0.20 d⁻¹. Sinking velocity increases with increasing aggregate size within homogeneous sources of aggregates. When compared across different particle and aggregate sources, however, sinking velocity appeared to be independent of particle or aggregate size. The carbon-specific respiration rate per meter settled varied between 0.0002 m⁻¹ and 0.0030 m⁻¹, and decreased with increasing aggregate size. It was lower for calcite ballasted aggregates as compared to that of similar sized opal ballasted aggregates.

Improvement of the photon flux measurement at the BGO-OD experiment

Energy Technology Data Exchange (ETDEWEB)

Kohl, Katrin [Physikalisches Institut, Universitaet Bonn (Germany); Collaboration: BGO-OD-Collaboration

2016-07-01

The BGO-OD experiment at the ELSA accelerator facility at Bonn investigates the internal reaction mechanisms of the nucleon, using an energy tagged bremsstrahlung photon beam. Absolute normalisation of the beam flux is required for cross section determination. In this talk the measurement principle is presented, and an improved method of the photon flux monitoring of the experiment is introduced.

Turbulent fluxes by "Conditional Eddy Sampling"

Science.gov (United States)

Siebicke, Lukas

2015-04-01

Turbulent flux measurements are key to understanding ecosystem scale energy and matter exchange, including atmospheric trace gases. While the eddy covariance approach has evolved as an invaluable tool to quantify fluxes of e.g. CO2 and H2O continuously, it is limited to very few atmospheric constituents for which sufficiently fast analyzers exist. High instrument cost, lack of field-readiness or high power consumption (e.g. many recent laser-based systems requiring strong vacuum) further impair application to other tracers. Alternative micrometeorological approaches such as conditional sampling might overcome major limitations. Although the idea of eddy accumulation has already been proposed by Desjardin in 1972 (Desjardin, 1977), at the time it could not be realized for trace gases. Major simplifications by Businger and Oncley (1990) lead to it's widespread application as 'Relaxed Eddy Accumulation' (REA). However, those simplifications (flux gradient similarity with constant flow rate sampling irrespective of vertical wind velocity and introduction of a deadband around zero vertical wind velocity) have degraded eddy accumulation to an indirect method, introducing issues of scalar similarity and often lack of suitable scalar flux proxies. Here we present a real implementation of a true eddy accumulation system according to the original concept. Key to our approach, which we call 'Conditional Eddy Sampling' (CES), is the mathematical formulation of conditional sampling in it's true form of a direct eddy flux measurement paired with a performant real implementation. Dedicated hardware controlled by near-real-time software allows full signal recovery at 10 or 20 Hz, very fast valve switching, instant vertical wind velocity proportional flow rate control, virtually no deadband and adaptive power management. Demonstrated system performance often exceeds requirements for flux measurements by orders of magnitude. The system's exceptionally low power consumption is ideal

Incision and Landsliding Lead to Coupled Increase in Sediment Flux and Grain Size Export

Science.gov (United States)

Roda-Boluda, D. C.; Brooke, S.; D'Arcy, M. K.; Whittaker, A. C.; Armitage, J. J.

2017-12-01

The rates and grain sizes of sediment fluxes modulate the dynamics and timing of landscape response to tectonics, and dictate the depositional patterns of sediment in basins. Over the last decades, we have gained a good quantitative understanding on how sediment flux and grain size may affect incision and basin stratigraphy. However, we comparably still have limited knowledge on how these variables change with varying tectonic rates. To address this question, we have studied 152 catchments along 8 normal fault-bounded ranges in southern Italy, which are affected by varying fault slip rates and experiencing a transient response to tectonics. Using a data set of 38 new and published 10Be erosion rates, we calibrate a sediment flux predictive equation (BQART), in order to estimate catchment sediment fluxes. We demonstrate that long-term sediment flux is governed by fault slip rates and the tectonically-controlled transient incision, and that sediment flux estimates from the BQART, steady-state assumptions, and incised volumes are highly correlated. This is supported by our 10Be erosion rates, which are controlled by fault slip and incision rates, and the associated landsliding. Based on a new landslide inventory, we show that erosion rate differences are likely due to differences in incision-related landslide activity across these catchments, and that landslides are a major component of sediment fluxes. From a data set of >13000 grain size counts on hillslope grain size supply and fluvial sediment at catchment outlets, we observe that landslides deliver material 20-200% coarser than other sediment sources, and that this coarse supply has an impact on the grain size distributions being exported from the catchments. Combining our sediment flux and grain size data sets, we are able to show that for our catchments, and potentially also for any areas that respond to changes in climate or tectonics via enhanced landsliding, sediment flux and grain size export increase

Identification, Calculation Of The Three Dimensional Orbit, And Flux Of Asteroid 2007 TD14

Science.gov (United States)

Pereira, Vincent; Martin, E.; Millan, J.

2012-01-01

In recent years the rate of discovery of asteroids has improved dramatically and has far outstripped efforts to physically characterize them. In this work, we took part in the International Astronomical Search Campaign and confirmed the discovery of asteroid 2007 TD14. We then calculated the two and three dimensional orbit of the asteroid around the sun, given its six elements of orbit. Once the heliocentric and geocentric distances are known, and the visual magnitude of the asteroid obtained through photometry, its diameter can be calculated assuming a suitable value for the albedo. The diameter was 0.718 km and the albedo was 0.039. Using the Standard Thermal Model we calculated the temperature distribution on the surface of the asteroid and the flux of the asteroid in the thermal infrared (1.095 mJy at 22 microns on March 19, 2010). To the best of our knowledge there have been no previous reports of the diameter and flux of the asteroid. Our ultimate goal is to compare our flux values with newly released data from NASA Wide-field Infrared Survey Explorer Mission and thus obtain better estimates of the asteroid diameter and albedo.

Rates and fluxes of centennial-scale carbon storage in the fine-grained sediments from the central South Yellow Sea and Min-Zhe belt, East China Sea

Science.gov (United States)

Wang, Jianghai; Xiao, Xi; Zhou, Qianzhi; Xu, Xiaoming; Zhang, Chenxi; Liu, Jinzhong; Yuan, Dongliang

2018-01-01

The global carbon cycle has played a key role in mitigating global warming and climate change. Long-term natural and anthropogenic processes influence the composition, sources, burial rates, and fluxes of carbon in sediments on the continental shelf of China. In this study, the rates, fluxes, and amounts of carbon storage at the centennial scale were estimated and demonstrated using the case study of three fine-grained sediment cores from the central South Yellow Sea area (SYSA) and Min-Zhe belt (MZB), East China Sea. Based on the high-resolution temporal sequences of total carbon (TC) and total organic carbon (TOC) contents, we reconstructed the annual variations of historical marine carbon storage, and explored the influence of terrestrial and marine sources on carbon burial at the centennial scale. The estimated TC storage over 100 years was 1.18×108 t in the SYSA and 1.45×109 t in the MZB. The corrected TOC storage fluxes at the centennial scale ranged from 17 to 28 t/(km2·a)in the SYSA and from 56 to 148 t/(km2·a) in the MZB. The decrease of terrestrial materials and the increase of marine primary production suggest that the TOC buried in the sediments in the SYSA and MZB was mainly derived from the marine autogenetic source. In the MZB, two depletion events occurred in TC and TOC storage from 1985 to 1987 and 2003 to 2006, which were coeval with the water impoundment in the Gezhouba and Three Gorges dams, respectively. The high-resolution records of the carbon storage rates and fluxes in the SYSA and MZB reflect the synchronous responses to human activities and provide an important reference for assessing the carbon sequestration capacity of the marginal seas of China.

Neutron flux measurements in C-9 capsule pressure tube

International Nuclear Information System (INIS)

Barbos, D.; Roth, C. S.; Gugiu, D.; Preda, M.

2001-01-01

C-9 capsule is a fuel testing facility in which the testing consists of a daily cycle ranging between the limits 100% power to 50% power. C-9 in-pile section with sample holder an instrumentation are introduced in G-9 and G-10 experimental channels. The experimental fuel channel has a maximum value when the in-pile section (pressure tube) is in G-9 channel and minimum value in G-10 channel. In this paper the main goals are determination or measurements of: - axial thermal neutron flux distribution in C-9 pressure tube both in G-9 and G-10 channel; - ratio of maximum neutron flux value in G-9 and the same value in G-9 channel and the same value in G-10 channel; - neutron flux-spectrum. On the basis of axial neutron flux distribution measurements, the experimental fuel element in sample holder position in set. Both axial neutron flux distribution of thermal neutrons and neutron flux-spectrum were performed using multi- foil activation technique. Activation rates were obtained by absolute measurements of the induced activity using gamma spectroscopy methods. To determine the axial thermal neutron flux distribution in G-9 and G-10, Cu 100% wire was irradiated at the reactor power of 2 MW. Ratio between the two maximum values, in G-9 and G-10 channels, is 2.55. Multi-foil activation method was used for neutron flux spectrum measurements. The neutron spectra and flux were obtained from reaction rate measurements by means of SAND 2 code. To obtain gamma-ray spectra, a HPGe detector connected to a multichannel analyzer was used. The spectrometer is absolute efficiency calibrated. The foils were irradiated at 2 MW reactor power in previously determined maximum flux position resulted from wire measurements. This reaction rates were normalized for 10 MW reactor power. Neutron self shielding corrections for the activation foils were applied. The self-shielding corrections are computed using Monte Carlo simulation methods. The measured integral flux is 1.1·10 14 n/cm 2 s

Third law of thermodynamics in the presence of a heat flux

International Nuclear Information System (INIS)

Camacho, J.

1995-01-01

Following a maximum entropy formalism, we study a one-dimensional crystal under a heat flux. We obtain the phonon distribution function and evaluate the nonequilibrium temperature, the specific heat, and the entropy as functions of the internal energy and the heat flux, in both the quantum and the classical limits. Some analogies between the behavior of equilibrium systems at low absolute temperature and nonequilibrium steady states under high values of the heat flux are shown, which point to a possible generalization of the third law in nonequilibrium situations

Interaction of storage carbohydrates and other cyclic fluxes with central metabolism : A quantitative approach by non-stationary 13C metabolic flux analysis

NARCIS (Netherlands)

Suarez-Mendez, C. A.; Hanemaaijer, M.; ten Pierick, Angela; Wolters, J. C.; Heijnen, J.J.; Wahl, S. A.

2016-01-01

13C labeling experiments in aerobic glucose limited cultures of Saccharomyces cerevisiae at four different growth rates (0.054; 0.101, 0.207, 0.307 h-1) are used for calculating fluxes that include intracellular cycles (e.g., storage carbohydrate cycles, exchange fluxes with amino acids), which are

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

International Nuclear Information System (INIS)

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

2016-01-01

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

Measurement and simulation of thermal neutron flux distribution in the RTP core

Science.gov (United States)

Rabir, Mohamad Hairie B.; Jalal Bayar, Abi Muttaqin B.; Hamzah, Na'im Syauqi B.; Mustafa, Muhammad Khairul Ariff B.; Karim, Julia Bt. Abdul; Zin, Muhammad Rawi B. Mohamed; Ismail, Yahya B.; Hussain, Mohd Huzair B.; Mat Husin, Mat Zin B.; Dan, Roslan B. Md; Ismail, Ahmad Razali B.; Husain, Nurfazila Bt.; Jalil Khan, Zareen Khan B. Abdul; Yakin, Shaiful Rizaide B. Mohd; Saad, Mohamad Fauzi B.; Masood, Zarina Bt.

2018-01-01

The in-core thermal neutron flux distribution was determined using measurement and simulation methods for the Malaysian’s PUSPATI TRIGA Reactor (RTP). In this work, online thermal neutron flux measurement using Self Powered Neutron Detector (SPND) has been performed to verify and validate the computational methods for neutron flux calculation in RTP calculations. The experimental results were used as a validation to the calculations performed with Monte Carlo code MCNP. The detail in-core neutron flux distributions were estimated using MCNP mesh tally method. The neutron flux mapping obtained revealed the heterogeneous configuration of the core. Based on the measurement and simulation, the thermal flux profile peaked at the centre of the core and gradually decreased towards the outer side of the core. The results show a good agreement (relatively) between calculation and measurement where both show the same radial thermal flux profile inside the core: MCNP model over estimation with maximum discrepancy around 20% higher compared to SPND measurement. As our model also predicts well the neutron flux distribution in the core it can be used for the characterization of the full core, that is neutron flux and spectra calculation, dose rate calculations, reaction rate calculations, etc.

Failure rate of inferior alveolar nerve block among dental students and interns.

Science.gov (United States)

AlHindi, Maryam; Rashed, Bayan; AlOtaibi, Noura

2016-01-01

To report the failure rate of inferior alveolar nerve block (IANB) among dental students and interns, causes of failure, investigate awareness of different IANB techniques, and to report IANB-associated complications.   A 3-page questionnaire containing 13 questions was distributed to a random sample of 350 third to fifth years students and interns at the College of Dentistry, King Saud University, Riyadh, Saudi Arabia on January 2011. It included demographic questions (age, gender, and academic level) and questions on IANB failure frequency and reasons, actions taken to overcome the failure, and awareness of different anesthetic techniques, supplementary techniques, and complications.   Of the 250 distributed questionnaires, 238 were returned (68% response rate). Most (85.7%) of surveyed sample had experienced IANB failure once or twice. The participants attributed the failures most commonly (66.45%) to anatomical variations. The most common alternative technique used was intraligamentary injection (57.1%), although 42.8% of the sample never attempted any alternatives. Large portion of the samples stated that they either lacked both knowledge of and training for other techniques (44.9%), or that they had knowledge of them but not enough training to perform them (45.8%).  To  decrease IANB failure rates for dental students and interns, knowledge of landmarks, anatomical variation and their training in alternatives to IANB, such as the Gow-Gates and Akinosi techniques, both theoretically and clinically in the dental curriculum should be enhanced.

Failure rate of inferior alveolar nerve block among dental students and interns

Directory of Open Access Journals (Sweden)

Maryam AlHindi

2016-01-01

Full Text Available Objectives: To report the failure rate of inferior alveolar nerve block (IANB among dental students and interns, causes of failure, investigate awareness of different IANB techniques, and to report IANB-associated complications. Methods: A 3-page questionnaire containing 13 questions was distributed to a random sample of 350 third to fifth years students and interns at the College of Dentistry, King Saud University, Riyadh, Saudi Arabia on January 2011. It included demographic questions (age, gender, and academic level and questions on IANB failure frequency and reasons, actions taken to overcome the failure, and awareness of different anesthetic techniques, supplementary techniques, and complications. Results: Of the 250 distributed questionnaires, 238 were returned (68% response rate. Most (85.7% of surveyed sample had experienced IANB failure once or twice. The participants attributed the failures most commonly (66.45% to anatomical variations. The most common alternative technique used was intraligamentary injection (57.1%, although 42.8% of the sample never attempted any alternatives. Large portion of the samples stated that they either lacked both knowledge of and training for other techniques (44.9%, or that they had knowledge of them but not enough training to perform them (45.8%. Conclusion: To decrease IANB failure rates for dental students and interns, knowledge of landmarks, anatomical variation and their training in alternatives to IANB, such as the Gow-Gates and Akinosi techniques, both theoretically and clinically in the dental curriculum should be enhanced.

Differentiating transpiration from evaporation in seasonal agricultural wetlands and the link to advective fluxes in the root zone

Science.gov (United States)

Bachand, P.A.M.; S. Bachand,; Fleck, Jacob A.; Anderson, Frank E.; Windham-Myers, Lisamarie

2014-01-01

The current state of science and engineering related to analyzing wetlands overlooks the importance of transpiration and risks data misinterpretation. In response, we developed hydrologic and mass budgets for agricultural wetlands using electrical conductivity (EC) as a natural conservative tracer. We developed simple differential equations that quantify evaporation and transpiration rates using flowrates and tracer concentrations atwetland inflows and outflows. We used two ideal reactormodel solutions, a continuous flowstirred tank reactor (CFSTR) and a plug flow reactor (PFR), to bracket real non-ideal systems. From those models, estimated transpiration ranged from 55% (CFSTR) to 74% (PFR) of total evapotranspiration (ET) rates, consistent with published values using standard methods and direct measurements. The PFR model more appropriately represents these nonideal agricultural wetlands in which check ponds are in series. Using a fluxmodel, we also developed an equation delineating the root zone depth at which diffusive dominated fluxes transition to advective dominated fluxes. This relationship is similar to the Peclet number that identifies the dominance of advective or diffusive fluxes in surface and groundwater transport. Using diffusion coefficients for inorganic mercury (Hg) and methylmercury (MeHg) we calculated that during high ET periods typical of summer, advective fluxes dominate root zone transport except in the top millimeters below the sediment–water interface. The transition depth has diel and seasonal trends, tracking those of ET. Neglecting this pathway has profound implications: misallocating loads along different hydrologic pathways; misinterpreting seasonal and diel water quality trends; confounding Fick's First Law calculations when determining diffusion fluxes using pore water concentration data; and misinterpreting biogeochemicalmechanisms affecting dissolved constituent cycling in the root zone. In addition,our understanding of internal

Determining Near-Bottom Fluxes of Passive Tracers in Aquatic Environments

Science.gov (United States)

Bluteau, Cynthia E.; Ivey, Gregory N.; Donis, Daphne; McGinnis, Daniel F.

2018-03-01

In aquatic systems, the eddy correlation method (ECM) provides vertical flux measurements near the sediment-water interface. The ECM independently measures the turbulent vertical velocities w' and the turbulent tracer concentration c' at a high sampling rate (> 1 Hz) to obtain the vertical flux w'c'¯ from their time-averaged covariance. This method requires identifying and resolving all the flow-dependent time (and length) scales contributing to w'c'¯. With increasingly energetic flows, we demonstrate that the ECM's current technology precludes resolving the smallest flux-contributing scales. To avoid these difficulties, we show that for passive tracers such as dissolved oxygen, w'c'¯ can be measured from estimates of two scalar quantities: the rate of turbulent kinetic energy dissipation ɛ and the rate of tracer variance dissipation χc. Applying this approach to both laboratory and field observations demonstrates that w'c'¯ is well resolved by the new method and can provide flux estimates in more energetic flows where the ECM cannot be used.

Expanded flux variability analysis on metabolic network of Escherichia coli

Institute of Scientific and Technical Information of China (English)

CHEN Tong; XIE ZhengWei; OUYANG Qi

2009-01-01

Flux balance analysis,based on the mass conservation law in a cellular organism,has been extensively employed to study the interplay between structures and functions of cellular metabolic networks.Consequently,the phenotypes of the metabolism can be well elucidated.In this paper,we introduce the Expanded Flux Variability Analysis (EFVA) to characterize the intrinsic nature of metabolic reactions,such as flexibility,modularity and essentiality,by exploring the trend of the range,the maximum and the minimum flux of reactions.We took the metabolic network of Escherichia coli as an example and analyzed the variability of reaction fluxes under different growth rate constraints.The average variability of all reactions decreases dramatically when the growth rate increases.Consider the noise effect on the metabolic system,we thus argue that the microorganism may practically grow under a suboptimal state.Besides,under the EFVA framework,the reactions are easily to be grouped into catabolic and anabolic groups.And the anabolic groups can be further assigned to specific biomass constitute.We also discovered the growth rate dependent essentiality of reactions.

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

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

Inverse modeling of the terrestrial carbon flux in China with flux covariance among inverted regions

Science.gov (United States)

Wang, H.; Jiang, F.; Chen, J. M.; Ju, W.; Wang, H.

2011-12-01

Quantitative understanding of the role of ocean and terrestrial biosphere in the global carbon cycle, their response and feedback to climate change is required for the future projection of the global climate. China has the largest amount of anthropogenic CO2 emission, diverse terrestrial ecosystems and an unprecedented rate of urbanization. Thus information on spatial and temporal distributions of the terrestrial carbon flux in China is of great importance in understanding the global carbon cycle. We developed a nested inversion with focus in China. Based on Transcom 22 regions for the globe, we divide China and its neighboring countries into 17 regions, making 39 regions in total for the globe. A Bayesian synthesis inversion is made to estimate the terrestrial carbon flux based on GlobalView CO2 data. In the inversion, GEOS-Chem is used as the transport model to develop the transport matrix. A terrestrial ecosystem model named BEPS is used to produce the prior surface flux to constrain the inversion. However, the sparseness of available observation stations in Asia poses a challenge to the inversion for the 17 small regions. To obtain additional constraint on the inversion, a prior flux covariance matrix is constructed using the BEPS model through analyzing the correlation in the net carbon flux among regions under variable climate conditions. The use of the covariance among different regions in the inversion effectively extends the information content of CO2 observations to more regions. The carbon flux over the 39 land and ocean regions are inverted for the period from 2004 to 2009. In order to investigate the impact of introducing the covariance matrix with non-zero off-diagonal values to the inversion, the inverted terrestrial carbon flux over China is evaluated against ChinaFlux eddy-covariance observations after applying an upscaling methodology.

Heat transfer characteristics for evaporation of R417A flowing inside horizontal smooth and internally grooved tubes

Energy Technology Data Exchange (ETDEWEB)

Xiaoyan, Zhang [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China); School of Energy Engineering, Xi' an University of Science and Technology, 58 Yanta Street, Xi' an, Shaanxi 710054 (China)], E-mail: gqzxy@sohu.com; Xingqun, Zhang; Yunguang, Chen; Xiuling, Yuan [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)

2008-06-15

The experimental study on evaporation heat transfer of R417A (R125/R134a/R600) flowing inside horizontal smooth and two internally grooved tubes with different geometrical parameters was conducted with the mass flow rate range from 176 to 344 kg m{sup -2} s{sup -1}, heat flux from 11 to 32 kW m{sup -2}, evaporation temperature from 0 to 5.5 deg. C and vapor quality from 0.2 to 1. Based on the experimental results, the mechanism and role of the mass flow rate, heat flux, vapor quality and enhanced surface influencing the evaporation heat transfer coefficients were analyzed and discussed. In comparison to R22, the evaporation heat transfer coefficients for R417A were lower and much lower in the internally grooved tubes than in the smooth tube. The present experimental results are also compared with the existing correlations, and the modified Kattan model is found to be in much better agreement with the experimental results than the Kattan model. The Koyama and Wellsandt microfin models all tend to over predict the evaporation heat transfer coefficients rather strongly for R417A inside internally grooved tubes.

Heat transfer characteristics for evaporation of R417A flowing inside horizontal smooth and internally grooved tubes

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaoyan [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China); School of Energy Engineering, Xi' an University of Science and Technology, 58 Yanta Street, Xi' an, Shaanxi 710054 (China); Zhang, Xingqun; Chen, Yunguang; Yuan, Xiuling [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)

2008-06-15

The experimental study on evaporation heat transfer of R417A (R125/R134a/R600) flowing inside horizontal smooth and two internally grooved tubes with different geometrical parameters was conducted with the mass flow rate range from 176 to 344 kg m{sup -2} s{sup -1}, heat flux from 11 to 32 kW m{sup -2}, evaporation temperature from 0 to 5.5{sup o}C and vapor quality from 0.2 to 1. Based on the experimental results, the mechanism and role of the mass flow rate, heat flux, vapor quality and enhanced surface influencing the evaporation heat transfer coefficients were analyzed and discussed. In comparison to R22, the evaporation heat transfer coefficients for R417A were lower and much lower in the internally grooved tubes than in the smooth tube. The present experimental results are also compared with the existing correlations, and the modified Kattan model is found to be in much better agreement with the experimental results than the Kattan model. The Koyama and Wellsandt microfin models all tend to over predict the evaporation heat transfer coefficients rather strongly for R417A inside internally grooved tubes. (author)

Heat transfer characteristics for evaporation of R417A flowing inside horizontal smooth and internally grooved tubes

International Nuclear Information System (INIS)

Zhang Xiaoyan; Zhang Xingqun; Chen Yunguang; Yuan Xiuling

2008-01-01

The experimental study on evaporation heat transfer of R417A (R125/R134a/R600) flowing inside horizontal smooth and two internally grooved tubes with different geometrical parameters was conducted with the mass flow rate range from 176 to 344 kg m -2 s -1 , heat flux from 11 to 32 kW m -2 , evaporation temperature from 0 to 5.5 deg. C and vapor quality from 0.2 to 1. Based on the experimental results, the mechanism and role of the mass flow rate, heat flux, vapor quality and enhanced surface influencing the evaporation heat transfer coefficients were analyzed and discussed. In comparison to R22, the evaporation heat transfer coefficients for R417A were lower and much lower in the internally grooved tubes than in the smooth tube. The present experimental results are also compared with the existing correlations, and the modified Kattan model is found to be in much better agreement with the experimental results than the Kattan model. The Koyama and Wellsandt microfin models all tend to over predict the evaporation heat transfer coefficients rather strongly for R417A inside internally grooved tubes

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.

Publication rates of public health theses in international and national peer-review journals in Turkey.

Science.gov (United States)

Sipahi, H; Durusoy, R; Ergin, I; Hassoy, H; Davas, A; Karababa, Ao

2012-01-01

Thesis is an important part of specialisation and doctorate education and requires intense work. The aim of this study was to investigate the publication rates of Turkish Public Health Doctorate Theses (PHDT) and Public Health Specialization (PHST) theses in international and Turkish national peer-review journals and to analyze the distribution of research areas. List of all theses upto 30 September 2009 were retrieved from theses database of the Council of Higher Education of the Republic of Turkey. The publication rates of these theses were found by searching PubMed, Science Citation Index-Expanded, Turkish Academic Network and Information Center (ULAKBIM) Turkish Medical Database, and Turkish Medline databases for the names of thesis author and mentor. The theses which were published in journals indexed either in PubMed or SCI-E were considered as international publications. Our search yielded a total of 538 theses (243 PHDT, 295 PHST). It was found that the overall publication rate in Turkish national journals was 18%. The overall publication rate in international journals was 11.9%. Overall the most common research area was occupational health. Publication rates of Turkish PHDT and PHST are low. A better understanding of factors affecting this publication rate is important for public health issues where national data is vital for better intervention programs and develop better public health policies.

78 FR 41129 - Market Test of Experimental Product - International Merchandise Return Service-Non-Published Rates

Science.gov (United States)

2013-07-09

...--Non-Published Rates AGENCY: U.S. Postal Service\\TM\\. ACTION: Notice. SUMMARY: The Postal Service hereby gives notice of a market test for International Merchandise Return Service--Non-Published Rates in... Return Service (IMRS) Non-published Rate (NPR) experimental product on August 15, 2013. The Postal...

EURISOL-DS Multi-MWatt Hg Target: Neutron flux and fission rate calculations for the MAFF configuration

CERN Document Server

Romanets, Y; Vaz, P; Herrera-Martinez, A; Kadi, Y; Kharoua, C; Lettry, J; Lindroos, M

The EURISOL (The EURopean Isotope Separation On-Line Radioactive Ion Beam) project aims at producing high intensity radioactive ion beams produced by neutron induced fission on a fissile target (235U) surrounding a liquid mercury converter. A proton beam of 1 GeV and 4 MW impinges on the Hg converter generating by spallation reactions high neutron fluxes. In this work the state-of-the-art Monte Carlo codes MCNPX and FLUKA were used to assess the neutronics performance of the system which geometry, inspired from the MAFF concept, allows a versatile manipulation of the fission targets. The objective of the study was to optimize the geometry of the system and the materials used in the fuel and reflector elements of the system, in order to achieve the highest possible fission rate.

Isoprene emission rates and fluxes measured above a Mediterranean oak ( Quercus pubescens) forest

Science.gov (United States)

Simon, V.; Dumergues, L.; Bouchou, P.; Torres, L.; Lopez, A.

2005-03-01

The present work, carried out as part of the European fiEld experimentS to COnstrain Models of atmospheric Pollution and Transport of Emissions project (ESCOMPTE), brings a new contribution to the inventory of the main natural hydrocarbons sources that are liable to participate in the production of ozone. The measurement campaign was conducted in Montmeyan, a site close to Marseilles (France), with the aim of quantifying the terpenic emission pattern and the behaviour of Quercus pubescens, an important Mediterranean tree species. Biogenic emissions by Q. pubescens were determined by the enclosure of an intact branch of this tree in a Teflon cuvette. The total monoterpenic emission rates thus recorded were found to reach maximum values ranged between 40 and 350 μg g Dry Weight-1 h -1. Emissions were correlated strongly with leaf temperature and Photosynthetic Active Radiation (PAR). The fluxes were also determined by extrapolating the results of the enclosure method and by using aerodynamic gradient method. They reach around 73 mg m -2 h -1 with the first method and 55 mg m -2 h -1 with the second one. The obtained values fit with a maximal ratio of 2.

Stochastic Discount Factor Approach to International Risk-Sharing: Evidence from Fixed Exchange Rate Episodes

NARCIS (Netherlands)

Hadzi-Vaskov, M.; Kool, C.J.M.

2007-01-01

This paper presents evidence of the stochastic discount factor approach to international risk-sharing applied to fixed exchange rate regimes. We calculate risk-sharing indices for two episodes of fixed or very rigid exchange rates: the Eurozone before and after the introduction of the Euro, and

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.

Interest-Rate Volatility in the Baltics: Issues of Measurement and International Contagion

OpenAIRE

Scott W. Hegerty

2015-01-01

Prior to their entry into the Eurozone, the Baltic countries of Estonia, Latvia, and Lithuania faced a major financial crisis that was brought about by events abroad. This financial risk led to instability in the real economy as well. This study uses monthly data to first model interest-rate volatility as a measure of financial instability before using our preferred volatility measure to test for international spillovers among interest-rate and output fluctuations. Vector Autoregressive (VAR)...

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.

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.

Stylized facts in internal rates of return on stock index and its derivative transactions

Science.gov (United States)

Pichl, Lukáš; Kaizoji, Taisei; Yamano, Takuya

2007-08-01

Universal features in stock markets and their derivative markets are studied by means of probability distributions in internal rates of return on buy and sell transaction pairs. Unlike the stylized facts in normalized log returns, the probability distributions for such single asset encounters incorporate the time factor by means of the internal rate of return, defined as the continuous compound interest. Resulting stylized facts are shown in the probability distributions derived from the daily series of TOPIX, S & P 500 and FTSE 100 index close values. The application of the above analysis to minute-tick data of NIKKEI 225 and its futures market, respectively, reveals an interesting difference in the behavior of the two probability distributions, in case a threshold on the minimal duration of the long position is imposed. It is therefore suggested that the probability distributions of the internal rates of return could be used for causality mining between the underlying and derivative stock markets. The highly specific discrete spectrum, which results from noise trader strategies as opposed to the smooth distributions observed for fundamentalist strategies in single encounter transactions may be useful in deducing the type of investment strategy from trading revenues of small portfolio investors.

Flux-split algorithms for flows with non-equilibrium chemistry and vibrational relaxation

Science.gov (United States)

Grossman, B.; Cinnella, P.

1990-01-01

The present consideration of numerical computation methods for gas flows with nonequilibrium chemistry thermodynamics gives attention to an equilibrium model, a general nonequilibrium model, and a simplified model based on vibrational relaxation. Flux-splitting procedures are developed for the fully-coupled inviscid equations encompassing fluid dynamics and both chemical and internal energy-relaxation processes. A fully coupled and implicit large-block structure is presented which embodies novel forms of flux-vector split and flux-difference split algorithms valid for nonequilibrium flow; illustrative high-temperature shock tube and nozzle flow examples are given.

Calculation with MCNP of capture photon flux in VVER-1000 experimental reactor.

Science.gov (United States)

Töre, Candan; Ortego, Pedro

2005-01-01

The aim of this study is to obtain by Monte Carlo method the high energy photon flux due to neutron capture in the internals and vessel layers of the experimental reactor LR-0 located in REZ, Czech Republic, and loaded with VVER-1000 fuel. The calclated neutron, photon and photon to neutron flux ratio are compared with experimental measurements performed with a multi-parameter stilbene detector. The results show clear underestimation of photon flux in downcomer and some overestimation at vessel surface and 1/4 thickness but a good fitting for deeper points in vessel.

Twofold reduction of phosphofructokinase activity in Lactococcus lactis results in strong decreases in growth rate and in glycolytic flux

DEFF Research Database (Denmark)

Andersen, Heidi Winterberg; Solem, Christian; Hammer, Karin

2001-01-01

reduced. Surprisingly, the mutants still showed homolactic fermentation, which indicated that the limitation was different from standard glucose-limited conditions, One explanation could be that the reduced activity of phosphofructokinase resulted in the accumulation of sugar-phosphates. Indeed, when one...... kinase and lactate dehydrogenase remained closer to the wild-type level. In defined medium supplemented with glucose, the growth rate of the mutants was reduced to 57 to 70% of wild-type levels and the glycolytic flux was reduced to 62 to 76% of wild-type levels. In complex medium growth was even further...... of the mutants was starved for glucose in glucose-limited chemostat, the growth rate could gradually be increased to 195% of the growth fate observed in glucose-saturated batch culture, suggesting that phosphofructokinase does affect the concentration of upstream metabolites. The pools of glucose-6- phosphate...

GAMSOR: Gamma Source Preparation and DIF3D Flux Solution

Energy Technology Data Exchange (ETDEWEB)

Smith, M. A. [TerraPower, Bellevue, WA (United States); Lee, C. H. [TerraPower, Bellevue, WA (United States); Hill, R. N. [TerraPower, Bellevue, WA (United States)

2017-06-28

Nuclear reactors that rely upon the fission reaction have two modes of thermal energy deposition in the reactor system: neutron absorption and gamma absorption. The gamma rays are typically generated by neutron capture reactions or during the fission process which means the primary driver of energy production is of course the neutron interaction. In conventional reactor physics methods, the gamma heating component is ignored such that the gamma absorption is forced to occur at the gamma emission site. For experimental reactor systems like EBR-II and FFTF, the placement of structural pins and assemblies internal to the core leads to problems with power heating predictions because there is no fission power source internal to the assembly to dictate a spatial distribution of the power. As part of the EBR-II support work in the 1980s, the GAMSOR code was developed to assist analysts in calculating the gamma heating. The GAMSOR code is a modified version of DIF3D and actually functions within a sequence of DIF3D calculations. The gamma flux in a conventional fission reactor system does not perturb the neutron flux and thus the gamma flux calculation can be cast as a fixed source problem given a solution to the steady state neutron flux equation. This leads to a sequence of DIF3D calculations, called the GAMSOR sequence, which involves solving the neutron flux, then the gamma flux, and then combining the results to do a summary edit. In this manuscript, we go over the GAMSOR code and detail how it is put together and functions. We also discuss how to setup the GAMSOR sequence and input for each DIF3D calculation in the GAMSOR sequence.

Towards direction dependent fluxes with AMS-02

Energy Technology Data Exchange (ETDEWEB)

Zeissler, Stefan; Andeen, Karen; Boer, Wim de; Gebauer, Iris; Merx, Carmen; Nikonov, Nikolay; Vagelli, Valerio [Karlsruher Institut fuer Technologie KIT (Germany)

2015-07-01

The Alpha Magnetic Spectrometer (AMS-02) is a state-of-the-art particle physics detector designed to operate as an external module on the International Space Station (ISS). In the unique space environment cosmic particles can be measured with high precision over an energy range from GeV up to TeV. In 2014 electron and positron flux measurements where published which indicate an additional source of positrons among the various cosmic particles. The arrival directions of energetic positrons and electrons convey fundamental information on their origin. We evaluate the AMS-02 detector acceptance for each incoming particle direction and show preliminary results of a direction dependent measurement of the AMS-02 lepton flux.

Efficiency in Assessment: Can Trained Student Interns Rate Essays as Well as Faculty Members?

Science.gov (United States)

Cole, Tracy L.; Cochran, Loretta F.; Troboy, L. Kim; Roach, David W.

2012-01-01

What are the most efficient and effective methods in measuring outcomes for assurance of learning in higher education? This study examines the merits of outsourcing part of the assessment workload by comparing ratings completed by trained student interns to ratings completed by faculty. Faculty evaluation of students' written work samples provides…

The impact of risk management on internal and sustainable growth rate: Evidence from Tehran Stock Exchange

Directory of Open Access Journals (Sweden)

Hamid Reza Vakili Fard

2014-09-01

Full Text Available Measuring the relative risk of firms has been an open discussion among researchers. There are many studies on learning how leverage may influence on growth of the firms. This article reviews the relationship between risk management, internal and sustainable growth of accepted companies in Tehran stock exchange. The survey considers three types of risks including operating, financial and compound and investigates their relationships with internal growth rate as well as sustainable growth rate. Using some regression techniques, the study has determined negative and meaningful relationships between different types of leverage on side and internal as well as sustainable growth on the other side.

Diagnostics of internal inductance in HT-7

International Nuclear Information System (INIS)

Zeng Li; Wan Baonian; Qian Jinping; Fan Hengyu

2001-01-01

Two arrays of Mirnov coils and a pair of concentric loops have been installed to superconducting tokamak HT-7. Software compensation and digital Fourier series expansion are the two techniques that have been applied successfully in measuring diamagnetic flux of concentric loops and internal inductance. The internal inductance of plasma l i , poloidal beta β p , Grad Shafranov parameter Λ, plasma minor radius α p and the center of the outermost magnetic flux surface Δ g are determined

Measurement of a thermal neutron flux using air activation; Mesure de flux de neutrons thermiques par activation d'air

Energy Technology Data Exchange (ETDEWEB)

Guyonvarh, M; Lecomte, P; Le Meur, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-07-01

It is necessary to know, in irradiation loops, the thermal neutron flux after the irradiation device has been introduced and without being obliged to wait for the discharge of this device. In order to measure the flux and to control it continuously, one possible method is to place in the flux a coiled steel tube through which air passes. By measuring the activity of argon 41, and with a knowledge of the flow rate and the temperature of the air, it is possible to calculate the flux. An air-circulation flux controller is described and the relationship between the flux and the count rate is established The accuracy of an absolute measurement is about 14 per cent; that of a relative measurement is about 3 per cent. The measurement can be carried out equally well whether the reactor is operating at maximum or at low power. The measurement range goes from 10{sup 9} to lO{sup 15} n.cm{sup -2}.sec{sup -1}, and it would be possible after a few modifications to measure fluxes between 10{sup 5} and 10{sup 15} n.cm{sup -2}.sec{sup -1}. Finally, the method is very safe to operate: there is little risk of irradiation because of the low specific activity of the argon-41 formed, and no risk of contamination because the decay product of argon-41 is stable. This method, which is now being used in loops, is thus very practical. (authors) [French] Sur des boucles d'irradiation il est necessaire de connaitre le flux de neutrons thermiques apres mise en place du dispositif d'irradiation et sans etre oblige d'attendre le detournement de ce dispositif. Pour mesurer le flux et le controler en permanence, une methode consiste a placer sous flux un serpentin en acier dans lequel on fait circuler de l'air. La mesure d'activite d'argon 41 permet de calculer le flux, connaissant le debit et la temperature de l'air. Un controleur de flux par circulation d'air est decrit et la relation entre le flux et le taux de comptage est etablie. La precision d'une mesure absolue est de l'ordre de 14 pour

Numerical Simulation of Internal Waves in the Andaman Sea

Science.gov (United States)

Mohanty, Sachiko; Devendra Rao, Ambarukhana

2017-04-01

The interactions of barotropic tides with irregular bottom topography generate internal waves with high amplitude known as large-amplitude internal waves (LAIW) in the Andaman Sea. These waves are an important phenomena in the ocean due to their influence on the density structure and energy transfer into the region. These waves are also important in submarine acoustics, underwater navigation, offshore structures, ocean mixing, biogeochemical processes, etc. over the shelf-slope region. In the present study, energetics analysis of M2 internal tides over the Andaman Sea is carried out in detail by using a three-dimensional MIT general circulation ocean model (MITgcm). In-situ observations of temperature, conductivity and currents with high temporal resolution are used to validate the model simulations. From the spectral energy estimate of density, it is found that the peak estimate is associated with the semi-diurnal frequency at all the depths in both observations and model simulations. The baroclinic velocity characteristics, suggests that a multi-mode features of baroclinic tides are present at the buoy location. To understand the generation and propagation of internal tides over this region, energy flux and barotropic-to-baroclinic M2 tidal energy conversion rates are examined. The model simulation suggests that the internal tide is generated at multiple sites and propagate off of their respective generation sources. Most of the energy propagation in the Andaman Sea follows the 1000m isobath. The maximum horizontal kinetic energy follows the energy flux pattern over the domain and the available potential energy is found to be maximum in the north of the Andaman Sea.

Homotopy Perturbation Method for Thin Film Flow and Heat Transfer over an Unsteady Stretching Sheet with Internal Heating and Variable Heat Flux

Directory of Open Access Journals (Sweden)

I-Chung Liu

2012-01-01

Full Text Available We have analyzed the effects of variable heat flux and internal heat generation on the flow and heat transfer in a thin film on a horizontal sheet in the presence of thermal radiation. Similarity transformations are used to transform the governing equations to a set of coupled nonlinear ordinary differential equations. The obtained differential equations are solved approximately by the homotopy perturbation method (HPM. The effects of various parameters governing the flow and heat transfer in this study are discussed and presented graphically. Comparison of numerical results is made with the earlier published results under limiting cases.

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.

Internal loading of phosphorus in western Lake Erie

Science.gov (United States)

Matisoff, Gerald; Kaltenberg, Eliza M.; Steely, Rebecca L.; Hummel, Stephanie K.; Seo, Jinyu; Gibbons, Kenneth J.; Bridgeman, Thomas B.; Seo, Youngwoo; Behbahani, Mohsen; James, William F.; Johnson, Laura; Doan, Phuong; Dittrich, Maria; Evans, Mary Anne; Chaffin, Justin D.

2016-01-01

This study applied eight techniques to obtain estimates of the diffusive flux of phosphorus (P) from bottom sediments throughout the western basin of Lake Erie. The flux was quantified from both aerobic and anaerobic incubations of whole cores; by monitoring the water encapsulated in bottom chambers; from pore water concentration profiles measured with a phosphate microelectrode, a diffusive equilibrium in thin films (DET) hydrogel, and expressed pore waters; and from mass balance and biogeochemical diagenetic models. Fluxes under aerobic conditions at summertime temperatures averaged 1.35 mg P/m2/day and displayed spatial variability on scales as small as a centimeter. Using two different temperature correction factors, the flux was adjusted to mean annual temperature yielding average annual fluxes of 0.43–0.91 mg P/m2/day and a western basin-wide total of 378–808 Mg P/year as the diffusive flux from sediments. This is 3–7% of the 11,000 Mg P/year International Joint Commission (IJC) target load for phosphorus delivery to Lake Erie from external sources. Using these average aerobic fluxes, the sediment contributes 3.0–6.3 μg P/L as a background internal contribution that represents 20–42% of the IJC Target Concentration of 15 μg P/L for the western basin. The implication is that this internal diffusive recycling of P is unlikely to trigger cyanobacterial blooms by itself but is sufficiently large to cause blooms when combined with external loads. This background flux may be also responsible for delayed response of the lake to any decrease in the external loading.

Le tourisme international dans le monde : logiques des flux et confins de la touristicité

Directory of Open Access Journals (Sweden)

Corina Tatar

2008-09-01

Full Text Available L’histoire du tourisme international des cinquante dernières années peut être décomposée en trois temps : 1/ les décennies de 1950 à 1980, caractérisées par une démocratisation progressive du tourisme soutenue par une croissance économique inégalée ; 2/ la dernière décennie du vingtième siècle, celle d’une euphorie touristique qui voit les frontières s’ouvrir. La fin d’un monde bipolaire annonce bien des espoirs naïfs. Le champ des territoires ouverts au tourisme ne cesse de s’élargir. 3/ La fin du siècle annonce l’âge de maturité du tourisme. Après l’euphorie, les illusions et les désillusions d’un espace touristique mondial sans frontières, les faits, souvent dramatiques ont fait prendre conscience aux touristes la complexité d’un monde où les guerres n’ont jamais cessé. L’espace touristique mondial est articulé autour de trois bassins régionaux : plus de 75% des flux touristiques internationaux, impulsés par les riches métropoles européennes, nord-américaines et asiatique, se cantonnent à dans leur espace régional d’origine. La distribution des flux touristiques dessine une organisation en trois bassins distincts : par ordre d’importance, 1/ le bassin euro-méditerranéen, centré sur la Mer méditerranée, 2/ le bassin Asie orientale-Pacifique, autour des rivages de la mer de Chine, 3/ le bassin Amérique du Nord -Caraïbes, organisé autour de la « Méditerranée américaine ». Les discontinuités s’affirment entre des périphéries mal stabilisées, des prolongements très sélectifs, des marges oubliées ou exclues. Les climats d’insécurité qui touchent certains territoires touristiques visent à fragiliser des périphéries plus sensibles et contraignent l’espace touristique international à se rétracter.The history of international tourism of the last fifty years can be divided  into three stages: 1 / decades from 1950 to 1980, characterized by a

Flux-profile relationships over a fetch limited beech forest

DEFF Research Database (Denmark)

Dellwik, E.; Jensen, N.O.

2005-01-01

The influence of an internal boundary layer and a roughness sublayer on flux-profile relationships for momentum and sensible heat have been investigated for a closed beech forest canopy with limited fetch conditions. The influence was quantified by derivation of local scaling functions for sensible...... heat flux and momentum (phi(h) and phi(m)) and analysed as a function of atmospheric stability and fetch. For heat, the influences of the roughness sublayer and the internal boundary layer were in agreement with previous studies. For momentum, the strong vertical gradient of the flow just above...... the canopy top for some wind sectors led to an increase in phi(m), a feature that has not previously been observed. For a fetch of 500 m over the beech forest during neutral atmospheric conditions, there is no height range at the site where profiles can be expected to be logarithmic with respect to the local...

Interpreting the variations in atmospheric methane fluxes observed above a restored wetland

DEFF Research Database (Denmark)

Herbst, Mathias; Friborg, Thomas; Ringgaard, Rasmus

2011-01-01

The eddy flux of methane (CH4) was measured over 14 months above a restored wetland in western Denmark. The average annual daily CH4 flux was 30.2mgm-2 d-1, but the daily emission rates varied considerably over time. Several factors were identified that explained some of this variation. (1) Grazing...... that the variability in the CH4 fluxes strongly affects the greenhouse gas sink strength of the restored wetland.......4 flux to soil temperature at 20cm depth was found for most of the study period, but not for parts of the summer season that coincided with a low water level in the river flowing through the wetland. (4) Additional variations in the CH4 emission rates were related to the spatial heterogeneity...

Oxygen, nitrogen and sulphide fluxes in the Black Sea

Directory of Open Access Journals (Sweden)

S.K. KONOVALOV

2000-12-01

Full Text Available The fluxes and production/consumption rates of oxygen, nitrate, ammonium and sulphide are estimated in the paper utilising results of the 1.5-dimensional stationary model of vertical exchange in the Black Sea (Samodurov & Ivanov, 1998. The profiles of the vertical flux and rate of production/consumption of these substances have revealed a number of intriguing features in the biogeochemical nature of the Black Sea. An approximate redox balance of the counter-fluxes of nitrate and ammonium into the sub-oxic zone has been revealed confirming that intensive denitrification may be the primary loss of nitrogen in the Black Sea. A low ratio of the nitrate stock to the flux of nitrate from the oxycline confirms the possibility of prominent changes in the distribution of nitrate on the time scale of a year. The ratio of the nitrate to oxygen vertical flux has revealed a lack of nitrate in the oxycline above the nitrate maximum. The lateral (related to the "Bosporus plume" flux of oxygen in the layer of the main pycnocline appears to be very important for the existing biogeochemical structure of the Black sea water column being the reason of sulphide consumption inside the anoxic zone and changes in the ammonium-sulphide stoichiometry of the anoxic zone, the primary reason of the existence of the sub-oxic layer and the basic reason of relative stability of the sulphide onset.

Methane oxidation and methane fluxes in the ocean surface layer and deep anoxic waters

Science.gov (United States)

Ward, B. B.; Kilpatrick, K. A.; Novelli, P. C.; Scranton, M. I.

1987-01-01

Measured biological oxidation rates of methane in near-surface waters of the Cariaco Basin are compared with the diffusional fluxes computed from concentration gradients of methane in the surface layer. Methane fluxes and oxidation rates were investigated in surface waters, at the oxic/anoxic interface, and in deep anoxic waters. It is shown that the surface-waters oxidation of methane is a mechanism which modulates the flux of methane from marine waters to the atmosphere.

Transient critical heat flux under flow coast-down in vertical annulus with non-uniform heat flux distribution

International Nuclear Information System (INIS)

Moon, S.K.; Chun, S.Y.; Choi, K.Y.; Yang, S.K.

2001-01-01

An experimental study on transient critical heat flux (CHF) under flow coast-down has been performed for water flow in a non-uniformly heated vertical annulus under low flow and a wide range of pressure conditions. The objectives of this study are to systematically investigate the effect of the flow transient on the CHF and to compare the transient CHF with steady state CHF. The transient CHF experiments have been performed for three kinds of flow transient modes based on the coast-down data of the Kori 3/4 nuclear power plant reactor coolant pump. Most of the CHFs occurred in the annular-mist flow regime. Thus, it means that the possible CHF mechanism might be the liquid film dryout in the annular-mist flow regime. For flow transient mode with the smallest flow reduction rate, the time-to-CHF is the largest. At the same inlet subcooling, system pressure and heat flux, the effect of the initial mass flux on the critical mass flux can be negligible. However, the effect of the initial mass flux on the time-to-CHF becomes large as the heat flux decreases. Usually, the critical mass flux is large for slow flow reduction. There is a pressure effect on the ratio of the transient CHF data to steady state CHF data. Some conventional correlations show relatively better CHF prediction results for high system pressure, high quality and slow transient modes than for low system pressure, low quality and fast transient modes. (author)

Internal heat gain from different light sources in the building lighting systems

Directory of Open Access Journals (Sweden)

Suszanowicz Dariusz

2017-01-01

Full Text Available EU directives and the Construction Law have for some time required investors to report the energy consumption of buildings, and this has indeed caused low energy consumption buildings to proliferate. Of particular interest, internal heat gains from installed lighting affect the final energy consumption for heating of both public and residential buildings. This article presents the results of analyses of the electricity consumption and the luminous flux and the heat flux emitted by different types of light sources used in buildings. Incandescent light, halogen, compact fluorescent bulbs, and LED bulbs from various manufacturers were individually placed in a closed and isolated chamber, and the parameters for their functioning under identical conditions were recorded. The heat flux emitted by 1 W nominal power of each light source was determined. Based on the study results, the empirical coefficients of heat emission and energy efficiency ratios for different types of lighting sources (dependent lamp power and the light output were designated. In the heat balance of the building, the designated rates allow for precise determination of the internal heat gains coming from lighting systems using various light sources and also enable optimization of lighting systems of buildings that are used in different ways.

Internal heat gain from different light sources in the building lighting systems

Science.gov (United States)

Suszanowicz, Dariusz

2017-10-01

EU directives and the Construction Law have for some time required investors to report the energy consumption of buildings, and this has indeed caused low energy consumption buildings to proliferate. Of particular interest, internal heat gains from installed lighting affect the final energy consumption for heating of both public and residential buildings. This article presents the results of analyses of the electricity consumption and the luminous flux and the heat flux emitted by different types of light sources used in buildings. Incandescent light, halogen, compact fluorescent bulbs, and LED bulbs from various manufacturers were individually placed in a closed and isolated chamber, and the parameters for their functioning under identical conditions were recorded. The heat flux emitted by 1 W nominal power of each light source was determined. Based on the study results, the empirical coefficients of heat emission and energy efficiency ratios for different types of lighting sources (dependent lamp power and the light output) were designated. In the heat balance of the building, the designated rates allow for precise determination of the internal heat gains coming from lighting systems using various light sources and also enable optimization of lighting systems of buildings that are used in different ways.

Water flux in animals: analysis of potential errors in the tritiated water method

International Nuclear Information System (INIS)

Nagy, K.A.; Costa, D.

1979-03-01

Laboratory studies indicate that tritiated water measurements of water flux are accurate to within -7 to +4% in mammals, but errors are larger in some reptiles. However, under conditions that can occur in field studies, errors may be much greater. Influx of environmental water vapor via lungs and skin can cause errors exceeding +-50% in some circumstances. If water flux rates in an animal vary through time, errors approach +-15% in extreme situations, but are near +-3% in more typical circumstances. Errors due to fractional evaporation of tritiated water may approach -9%. This error probably varies between species. Use of an inappropriate equation for calculating water flux from isotope data can cause errors exceeding +-100%. The following sources of error are either negligible or avoidable: use of isotope dilution space as a measure of body water volume, loss of nonaqueous tritium bound to excreta, binding of tritium with nonaqueous substances in the body, radiation toxicity effects, and small analytical errors in isotope measurements. Water flux rates measured with tritiated water should be within +-10% of actual flux rates in most situations

Water flux in animals: analysis of potential errors in the tritiated water method

Energy Technology Data Exchange (ETDEWEB)

Nagy, K.A.; Costa, D.

1979-03-01

Laboratory studies indicate that tritiated water measurements of water flux are accurate to within -7 to +4% in mammals, but errors are larger in some reptiles. However, under conditions that can occur in field studies, errors may be much greater. Influx of environmental water vapor via lungs and skin can cause errors exceeding +-50% in some circumstances. If water flux rates in an animal vary through time, errors approach +-15% in extreme situations, but are near +-3% in more typical circumstances. Errors due to fractional evaporation of tritiated water may approach -9%. This error probably varies between species. Use of an inappropriate equation for calculating water flux from isotope data can cause errors exceeding +-100%. The following sources of error are either negligible or avoidable: use of isotope dilution space as a measure of body water volume, loss of nonaqueous tritium bound to excreta, binding of tritium with nonaqueous substances in the body, radiation toxicity effects, and small analytical errors in isotope measurements. Water flux rates measured with tritiated water should be within +-10% of actual flux rates in most situations.

Modeling and prototyping of a flux concentrator for positron capture

International Nuclear Information System (INIS)

Liu, W.; Gai, W.; Wang, H.; Wong, T.

2008-01-01

An adiabatic matching device (AMD) generates a tapered high-strength magnetic field to capture positrons emitted from a positron target to a downstream accelerating structure. The AMD is a key component of a positron source and represents a technical challenge. The International Linear Collider collaboration is proposing to employ a pulsed, normal-conducting, flux-concentrator to generate a 5 Tesla initial magnetic field. The flux-concentrator structure itself and the interactions between the flux-concentrator and the external power supply circuits give rise to a nontrivial system. In this paper, we present a recently developed equivalent circuit model for a flux concentrator, along with the characteristics of a prototype fabricated for validating the model. Using the model, we can obtain the transient response of the pulsed magnetic field and the field profile. Calculations based on the model and the results of measurements made on the prototype are in good agreement.

Financial modeling in medicine: cash flow, basic metrics, the time value of money, discount rates, and internal rate of return.

Science.gov (United States)

Lexa, Frank James; Berlin, Jonathan W

2005-03-01

In this article, the authors cover tools for financial modeling. Commonly used time lines and cash flow diagrams are discussed. Commonly used but limited terms such as payback and breakeven are introduced. The important topics of the time value of money and discount rates are introduced to lay the foundation for their use in modeling and in more advanced metrics such as the internal rate of return. Finally, the authors broach the more sophisticated topic of net present value.

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

Flux control-based design of furfural-resistance strains of Saccharomyces cerevisiae for lignocellulosic biorefinery.

Science.gov (United States)

Unrean, Pornkamol

2017-04-01

We have previously developed a dynamic flux balance analysis of Saccharomyces cerevisiae for elucidation of genome-wide flux response to furfural perturbation (Unrean and Franzen, Biotechnol J 10(8):1248-1258, 2015). Herein, the dynamic flux distributions were analyzed by flux control analysis to identify target overexpressed genes for improved yeast robustness against furfural. The flux control coefficient (FCC) identified overexpressing isocitrate dehydrogenase (IDH1), a rate-controlling flux for ethanol fermentation, and dicarboxylate carrier (DIC1), a limiting flux for cell growth, as keys of furfural-resistance phenotype. Consistent with the model prediction, strain characterization showed 1.2- and 2.0-fold improvement in ethanol synthesis and furfural detoxification rates, respectively, by IDH1 overexpressed mutant compared to the control. DIC1 overexpressed mutant grew at 1.3-fold faster and reduced furfural at 1.4-fold faster than the control under the furfural challenge. This study hence demonstrated the FCC-based approach as an effective tool for guiding the design of robust yeast strains.

Rates of peer victimization in young adolescents with ADHD and associations with internalizing symptoms and self-esteem.

Science.gov (United States)

Becker, Stephen P; Mehari, Krista R; Langberg, Joshua M; Evans, Steven W

2017-02-01

The purposes of the present study were to: (1) describe rates of peer victimization in young adolescents with attention-deficit/hyperactivity disorder, (2) evaluate the association between types of peer victimization (i.e., physical, relational, and reputational) and internalizing problems (i.e., anxiety, depression, and self-esteem), and (3) examine whether associations between victimization and internalizing problems differ for males or females. Participants were 131 middle-school students (ages 11-15 years, 73 % male, 76 % White) diagnosed with ADHD who completed ratings of victimization, anxiety, depression, and self-esteem. Over half of the participants (57 %) reported experiencing at least one victimization behavior at a rate of once per week or more, with higher rates of relational victimization (51 %) than reputational victimization (17 %) or physical victimization (14 %). Males reported experiencing more physical victimization than females, but males and females did not differ in rates of relational or reputational victimization. Whereas relational and physical victimization were both uniquely associated with greater anxiety for both males and females, relational victimization was associated with greater depressive symptoms and lower self-esteem for males but not females. These findings indicate that young adolescents with ADHD frequently experience peer victimization and that the association between victimization and internalizing problems among young adolescents with ADHD differs as a result of victimization type, internalizing domain, and sex.

Plasma-materials interaction issues for the International Thermonuclear Experimental Reactor (ITER)

International Nuclear Information System (INIS)

Cohen, S.A.; Werley, K.A.

1992-02-01

Analysis of proposed operating scenarios for the International Thermonuclear Experimental Reactor has yielded predictions for the power and particle fluxes onto the material surfaces facing the plasma. The particles, mostly deuterium, tritium, and helium ions, would have energies in the range of 50--2000 eV and fluxes up to 5 x 10 23 /m 2 s. Lower fluxes of multi-MeV electrons and alpha particles may also strike the plasma-facing surfaces, primarily during transient events. The peak power fluxes onto the plasma-facing surfaces during normal operation are expected to be 5--100 MW/m 2 , but much higher during transient events. At the extreme conditions expected for steady-state operation, commonly used heat-removal structures are unable to withstand either the high sputter erosion rates or power loads. To reduce the time-averaged power flux, active control of the plasma position is specified to sweep the plasma heat load across larger areas of plasma-facing components. However, the cyclic heat load creates fatigue lifetime problems. Solutions to these lifetime and reliability problems by (1) changes in machine design and operation, (2) redeposition mechanisms, and (3) changes in materials, will be discussed. A proposed accelerated-life test facility for prototype divertor plate development is described

Brownian diode: Molecular motor based on a semi-permeable Brownian particle with internal potential drop

International Nuclear Information System (INIS)

Plyukhin, A.V.

2013-01-01

A model of an autonomous isothermal Brownian motor with an internal propulsion mechanism is considered. The motor is a Brownian particle which is semi-transparent for molecules of surrounding ideal gas. Molecular passage through the particle is controlled by a potential similar to that in the transition rate theory, i.e. characterized by two stationary states with a finite energy difference separated by a potential barrier. The internal potential drop maintains the diode-like asymmetry of molecular fluxes through the particle, which results in the particle's stationary drift.

76 FR 2930 - International Product Change-Global Expedited Package Services-Non- Published Rates

Science.gov (United States)

2011-01-18

... POSTAL SERVICE International Product Change--Global Expedited Package Services-- Non- Published... request with the Postal Regulatory Commission to add Global Expedited Package Services-- Non-Published...--Non-Published Rates, to the Competitive Products List, and Notice of Filing (Under Seal) the Enabling...

Ten years operating experience at the Fast Flux Test Facility: A decade of excellence

International Nuclear Information System (INIS)

Swaim, D.J.; Waldo, J.B.; Farabee, O.A.

1991-07-01

The Fast Flux Test Facility is a 400 MW(t) fast reactor cooled by three sodium loops. The Fast Flux Test Facility is managed by the Westinghouse Hanford Company for the US Department of Energy. The Fast Flux Test Facility was designed and constructed to provide irradiation testing of fuels and materials for the US Department of Energy Liquid Metal Reactor research program. Facility activities have increased to include fusion power materials testing, passive safety testing, isotope production, and international collaboration. 5 figs

Factors Controlling Nitrogen Fluxes in Groundwater in Agricultural Areas

Science.gov (United States)

Liao, L.; Green, C. T.; Bekins, B. A.; Bohlke, J. K.

2010-12-01

Predictions of effects of land use changes on water quality require identification of the relative importance of geochemical and hydrologic factors. To understand the factors controlling the transport of nitrogen in groundwater, vertical fluxes of water and solutes were estimated for 13 aquifers in agricultural areas located in California, Iowa, Maryland, Minnesota, Mississippi, Nebraska, North Carolina, Texas, and Wisconsin. The aquifers are overlain by unsaturated zones with thicknesses ranging from 2.5 to 100 m. Precipitation ranges from 19 to 132 cm/yr and irrigation ranges from 0 to 120 cm/yr. Main crop types include corn, soybeans, forage, wheat, and cotton. A 1-dimensional mathematical model was developed to estimate vertical N transport in response to N inputs on the land surface from chemical fertilizer, manure and atmospheric deposition. Simulated vertical profiles of O2, NO3-, N2 from denitrification, Cl- and atmospheric age tracers were matched to observations by adjusting parameters for recharge rate, unsaturated zone travel time, N leaching ratio (defined as leaching fraction of N reaching water table of N input at land surface), Cl- leaching ratio, O2 reduction rate and denitrification rate. Results indicated that vertical NO3 fluxes below the water table were affected by both geochemical and physical factors. High vertical NO3 fluxes below the water table are associated with high N input at the land surface. Values of Cl- leaching ratios were less than 1 (0.42 to 1) likely as a result of runoff and exported harvested crops. N leaching ratios were lower (0.1 to 0.6), consistent with additional N losses such as denitrification and volatilization. The sites with high leaching ratios for both N and Cl tended to be those with high recharge rates and low ET loss, defined as the fraction of applied water lost to ET. Modeled zero-order denitrification rates in the saturated zone varied within an order of magnitude with a maximum rate of 1.6 mg

The role of soil weathering and hydrology in regulating chemical fluxes from catchments (Invited)

Science.gov (United States)

Maher, K.; Chamberlain, C. P.

2010-12-01

Catchment-scale chemical fluxes have been linked to a number of different parameters that describe the conditions at the Earth’s surface, including runoff, temperature, rock type, vegetation, and the rate of tectonic uplift. However, many of the relationships relating chemical denudation to surface processes and conditions, while based on established theoretical principles, are largely empirical and derived solely from modern observations. Thus, an enhanced mechanistic basis for linking global solute fluxes to both surface processes and climate may improve our confidence in extrapolating modern solute fluxes to past and future conditions. One approach is to link observations from detailed soil-based studies with catchment-scale properties. For example, a number of recent studies of chemical weathering at the soil-profile scale have reinforced the importance of hydrologic processes in controlling chemical weathering rates. An analysis of data from granitic soils shows that weathering rates decrease with increasing fluid residence times and decreasing flow rates—over moderate fluid residence times, from 5 days to 10 years, transport-controlled weathering explains the orders of magnitude variation in weathering rates to a better extent than soil age. However, the importance of transport-controlled weathering is difficult to discern at the catchment scale because of the range of flow rates and fluid residence times captured by a single discharge or solute flux measurement. To assess the importance of transport-controlled weathering on catchment scale chemical fluxes, we present a model that links the chemical flux to the extent of reaction between the soil waters and the solids, or the fluid residence time. Different approaches for describing the distribution of fluid residence times within a catchment are then compared with the observed Si fluxes for a limited number of catchments. This model predicts high solute fluxes in regions with high run-off, relief, and

Constraining Genome-Scale Models to Represent the Bow Tie Structure of Metabolism for 13C Metabolic Flux Analysis

Directory of Open Access Journals (Sweden)

Tyler W. H. Backman

2018-01-01

Full Text Available Determination of internal metabolic fluxes is crucial for fundamental and applied biology because they map how carbon and electrons flow through metabolism to enable cell function. 13 C Metabolic Flux Analysis ( 13 C MFA and Two-Scale 13 C Metabolic Flux Analysis (2S- 13 C MFA are two techniques used to determine such fluxes. Both operate on the simplifying approximation that metabolic flux from peripheral metabolism into central “core” carbon metabolism is minimal, and can be omitted when modeling isotopic labeling in core metabolism. The validity of this “two-scale” or “bow tie” approximation is supported both by the ability to accurately model experimental isotopic labeling data, and by experimentally verified metabolic engineering predictions using these methods. However, the boundaries of core metabolism that satisfy this approximation can vary across species, and across cell culture conditions. Here, we present a set of algorithms that (1 systematically calculate flux bounds for any specified “core” of a genome-scale model so as to satisfy the bow tie approximation and (2 automatically identify an updated set of core reactions that can satisfy this approximation more efficiently. First, we leverage linear programming to simultaneously identify the lowest fluxes from peripheral metabolism into core metabolism compatible with the observed growth rate and extracellular metabolite exchange fluxes. Second, we use Simulated Annealing to identify an updated set of core reactions that allow for a minimum of fluxes into core metabolism to satisfy these experimental constraints. Together, these methods accelerate and automate the identification of a biologically reasonable set of core reactions for use with 13 C MFA or 2S- 13 C MFA, as well as provide for a substantially lower set of flux bounds for fluxes into the core as compared with previous methods. We provide an open source Python implementation of these algorithms at https://github.com/JBEI/limitfluxtocore.

A process-based model to estimate gas exchange and monoterpene emission rates in the mediterranean maquis - comparisons between modelled and measured fluxes at different scales

Science.gov (United States)

Vitale, M.; Matteucci, G.; Fares, S.; Davison, B.

2009-02-01

This paper concerns the application of a process-based model (MOCA, Modelling of Carbon Assessment) as an useful tool for estimating gas exchange, and integrating the empirical algorithms for calculation of monoterpene fluxes, in a Mediterranean maquis of central Italy (Castelporziano, Rome). Simulations were carried out for a range of hypothetical but realistic canopies of the evergreen Quercus ilex (holm oak), Arbutus unedo (strawberry tree) and Phillyrea latifolia. More, the dependence on total leaf area and leaf distribution of monoterpene fluxes at the canopy scale has been considered in the algorithms. Simulation of the gas exchange rates showed higher values for P. latifolia and A. unedo (2.39±0.30 and 3.12±0.27 gC m-2 d-1, respectively) with respect to Q. ilex (1.67±0.08 gC m-2 d-1) in the measuring campaign (May-June). Comparisons of the average Gross Primary Production (GPP) values with those measured by eddy covariance were well in accordance (7.98±0.20 and 6.00±1.46 gC m-2 d-1, respectively, in May-June), although some differences (of about 30%) were evident in a point-to-point comparison. These differences could be explained by considering the non uniformity of the measuring site where diurnal winds blown S-SW direction affecting thus calculations of CO2 and water fluxes. The introduction of some structural parameters in the algorithms for monoterpene calculation allowed to simulate monoterpene emission rates and fluxes which were in accord to those measured (6.50±2.25 vs. 9.39±4.5μg g-1DW h-1 for Q. ilex, and 0.63±0.207μg g-1DW h-1 vs. 0.98±0.30μg g-1DW h-1 for P. latifolia). Some constraints of the MOCA model are discussed, but it is demonstrated to be an useful tool to simulate physiological processes and BVOC fluxes in a very complicated plant distributions and environmental conditions, and necessitating also of a low number of input data.

Carbon Flux of Down Woody Materials in Forests of the North Central United States

International Nuclear Information System (INIS)

Woodall, C.W.

2010-01-01

Across large scales, the carbon (C) flux of down woody material (DWM) detrital pools has largely been simulated based on forest stand attributes (e.g., stand age and forest type). The annual change in forest DWM C stocks and other attributes (e.g., size and decay class changes) was assessed using a forest inventory in the north central United States to provide an empirical assessment of strategic-scale DWM C flux. Using DWM inventory data from the USDA Forest Service's Forest Inventory and Analysis program, DWM C stocks were found to be relatively static across the study region with an annual flux rate not statistically different from zero. Mean C flux rates across the study area were -0.25, -0.12, -0.01, and -0.04 (Mg/ha/yr) for standing live trees, standing dead trees, coarse woody debris, and fine woody debris, respectively. Flux rates varied in their both magnitude and status (emission/sequestration) by forest types, latitude, and DWM component size. Given the complex dynamics of DWM C flux, early implementation of inventory re measurement, and relatively low sample size, numerous future research directions are suggested.

Leaf, branch, stand and landscape scale measurements of volatile organic compound fluxes from U. S. woodlands

Energy Technology Data Exchange (ETDEWEB)

Guenther, A.; Greenberg, J.; Harley, P.; Helmig, D.; Klinger, L.; Vierling, L.; Zimmerman, P. [National Center for Atmospheric Research, Boulder, CO (United States). Atmospheric Chemistry Div.; Geron, C. [Environmental Protection Agency, Research Triangle Park, NC (United States)

1996-01-01

Natural volatile organic compound (VOC) fluxes were measured in three U.S. woodlands. Fluxes from individual leaves and branches were estimated with enclosure techniques and used to initialize and evaluate VOC emission model estimates. Ambient measurements were used to estimate above canopy fluxes for entire stands. A total of 78 VOCs were identified, with hexenol derivatives being the most commonly observed oxygenated compounds. There was also evidence of high rates of isoprene emission and high rates of monoterpenes in some genera of trees. Model predictions of diurnal variations were within + or - 35 per cent of observed flux variations. Fluxes predicted by a recent version of a biogenic emission model were within 10 per cent to 50 per cent of observed fluxes, leading to the conclusion that existing databases can provide isoprene and monoterpene emission rate potentials within acceptable limits for the dominant plant species at these three woodland sites. 21 refs., 5 tabs., 2 figs.

The I.A.G. / A.I.G. SEDIBUD Book Project: Source-to-Sink Fluxes in Undisturbed Cold Environments

Science.gov (United States)

Beylich, Achim A.; Dixon, John C.; Zwolinski, Zbigniew

2015-04-01

The currently prepared SEDIBUD Book on "Source-to-Sink Fluxes in Undisturbed Cold Environments" (edited by Achim A. Beylich, John C. Dixon and Zbigniew Zwolinski and published by Cambridge University Press) is summarizing and synthesizing the achievements of the International Association of Geomorphologists` (I.A.G./A.I.G.) Working Group SEDIBUD (Sediment Budgets in Cold Environments), which has been active since 2005 (http://www.geomorph.org/wg/wgsb.html). Amplified climate change and ecological sensitivity of largely undisturbed polar and high-altitude cold climate environments have been highlighted as key global environmental issues. The effects of projected climate change will change surface environments in cold regions and will alter the fluxes of sediments, nutrients and solutes, but the absence of quantitative data and coordinated geomorphic process monitoring and analysis to understand the sensitivity of the Earth surface environment in these largely undisturbed environments is acute. Our book addresses this existing key knowledge gap. The applied approach of integrating comparable and longer-term field datasets on contemporary solute and sedimentary fluxes from a number of different defined cold climate catchment geosystems for better understanding (i) the environmental drivers and rates of contemporary denudational surface processes and (ii) possible effects of projected climate change in cold regions is unique in the field of geomorphology. Largely undisturbed cold climate environments can provide baseline data for modeling the effects of environmental change. The book synthesizes work carried out by numerous SEDIBUD Members over the last decade in numerous cold climate catchment geosystems worldwide. For reaching a global cover of different cold climate environments the book is - after providing an introduction part and a basic part on climate change in cold environments and general implications for solute and sedimentary fluxes - dealing in different

Mixed convection in inclined lid driven cavity by Lattice Boltzmann Method and heat flux boundary condition

International Nuclear Information System (INIS)

D'Orazio, A; Karimipour, A; Nezhad, A H; Shirani, E

2014-01-01

Laminar mixed convective heat transfer in two-dimensional rectangular inclined driven cavity is studied numerically by means of a double population thermal Lattice Boltzmann method. Through the top moving lid the heat flux enters the cavity whereas it leaves the system through the bottom wall; side walls are adiabatic. The counter-slip internal energy density boundary condition, able to simulate an imposed non zero heat flux at the wall, is applied, in order to demonstrate that it can be effectively used to simulate heat transfer phenomena also in case of moving walls. Results are analyzed over a range of the Richardson numbers and tilting angles of the enclosure, encompassing the dominating forced convection, mixed convection, and dominating natural convection flow regimes. As expected, heat transfer rate increases as increases the inclination angle, but this effect is significant for higher Richardson numbers, when buoyancy forces dominate the problem; for horizontal cavity, average Nusselt number decreases with the increase of Richardson number because of the stratified field configuration

FluxVisualizer, a Software to Visualize Fluxes through Metabolic Networks

Directory of Open Access Journals (Sweden)

Tim Daniel Rose

2018-04-01

Full Text Available FluxVisualizer (Version 1.0, 2017, freely available at https://fluxvisualizer.ibgc.cnrs.fr is a software to visualize fluxes values on a scalable vector graphic (SVG representation of a metabolic network by colouring or increasing the width of reaction arrows of the SVG file. FluxVisualizer does not aim to draw metabolic networks but to use a customer’s SVG file allowing him to exploit his representation standards with a minimum of constraints. FluxVisualizer is especially suitable for small to medium size metabolic networks, where a visual representation of the fluxes makes sense. The flux distribution can either be an elementary flux mode (EFM, a flux balance analysis (FBA result or any other flux distribution. It allows the automatic visualization of a series of pathways of the same network as is needed for a set of EFMs. The software is coded in python3 and provides a graphical user interface (GUI and an application programming interface (API. All functionalities of the program can be used from the API and the GUI and allows advanced users to add their own functionalities. The software is able to work with various formats of flux distributions (Metatool, CellNetAnalyzer, COPASI and FAME export files as well as with Excel files. This simple software can save a lot of time when evaluating fluxes simulations on a metabolic network.

Sodium Flux Growth of Bulk Gallium Nitride

Science.gov (United States)

Von Dollen, Paul Martin

This dissertation focused on development of a novel apparatus and techniques for crystal growth of bulk gallium nitride (GaN) using the sodium flux method. Though several methods exist to produce bulk GaN, none have been commercialized on an industrial scale. The sodium flux method offers potentially lower cost production due to relatively mild process conditions while maintaining high crystal quality. But the current equipment and methods for sodium flux growth of bulk GaN are generally not amenable to large-scale crystal growth or in situ investigation of growth processes, which has hampered progress. A key task was to prevent sodium loss or migration from the sodium-gallium growth melt while permitting N2 gas to access the growing crystal, which was accomplished by implementing a reflux condensing stem along with a reusable sealed capsule. The reflux condensing stem also enabled direct monitoring and control of the melt temperature, which has not been previously reported for the sodium flux method. Molybdenum-based materials were identified from a corrosion study as candidates for direct containment of the corrosive sodium-gallium melt. Successful introduction of these materials allowed implementation of a crucible-free containment system, which improved process control and can potentially reduce crystal impurity levels. Using the new growth system, the (0001) Ga face (+c plane) growth rate was >50 mum/hr, which is the highest bulk GaN growth rate reported for the sodium flux method. Omega X-ray rocking curve (?-XRC) measurements indicated the presence of multiple grains, though full width at half maximum (FWHM) values for individual peaks were 1020 atoms/cm3, possibly due to reactor cleaning and handling procedures. This dissertation also introduced an in situ technique to correlate changes in N2 pressure with dissolution of nitrogen and precipitation of GaN from the sodium-gallium melt. Different stages of N2 pressure decay were identified and linked to

Optimization of the testing volumes with respect to neutron flux levels in the two-target high flux D-Li neutron source for the international fusion materials irradiation facility

International Nuclear Information System (INIS)

Kelleher, W.P.; Varsamis, G.L.

1989-01-01

An economic and fusion-relevant source of high-energy neutrons is an essential element in the fusion nuclear technology and development program. This source can be generated by directing a high energy deuteron beam onto a flowing liquid lithium target, producing neutrons via the D-Lithium stripping reaction. Previous work on this type of source concentrated on a design employing one deuteron beam of modest amperage. This design was shown to have a relatively small testing volume with high flux gradients and was therefor considered somewhat unattractive from a materials testing standpoint. A design using two lithium targets and two high-amperage beams has recently been proposed. This two beam design has been examined in an effort to maximize the test volume while minimizing the flux gradients and minimizing the effect of radiation damage on one target due to the other. A spatial, energy and angle dependent neutron source modeling the D-Lithium source was developed. Using this source, a 3-dimensional map of uncollided flux within the test volume was calculated. The results showed that the target separation has little effect on the available experimental volume and that a testing volume of ∼35 liters is available with a volume averaged flux above 10 14 n/cm 2 /s. The collided flux within the test volume was then determined by coupling the source model with a Monte Carlo code. The spectral effects of the high-energy tail in the flux were examined and evaluated as to possible effects on materials response. Calculations comparing the radiation damage to materials from the D-Lithium source to that cause by a standard DT fusion first-wall neutron flux spectrum showed that the number of appm and dpa, as well as the ratio appm/dpa and dpa/MW/m 2 are within 30% for the two sources. 8 refs., 8 figs

THE MANAGEMENT OF CREDIT RISK ACCORDING TO INTERNAL RATINGS- BASED APPROACH

Directory of Open Access Journals (Sweden)

BOLOCAN DRAGOS-MIHAIL

2010-12-01

Full Text Available The internal ratings based approach (IRB Approach was created as part of Basel II replacing the original Basle Accord of 1988 (Basle I in an effort to create a better framework for regulating bank capital. This paper covers the methodology and components of the IRB Approach used to determine capital requirements for credit risk. Such an approach, which relies heavily upon a banks internal assessment of its counterparties and exposures, can secure two key objectives consistent with those which support the wider review of The New Basel Capital Accord.. IRB approach should promote safety and soundness in the financial system and, consistent with providing incentive compatibility, that the structure and requirements of the IRB approach do not impinge upon or undermine banks well-established lending and credit risk management practices

An intermetallic powder-in-tube approach to increased flux-pinning in Nb3Sn by internal oxidation of Zr

Science.gov (United States)

Motowidlo, L. R.; Lee, P. J.; Tarantini, C.; Balachandran, S.; Ghosh, A. K.; Larbalestier, D. C.

2018-01-01

We report on the development of multifilamentary Nb3Sn superconductors by a versatile powder-in-tube technique (PIT) that demonstrates a simple pathway to a strand with a higher density of flux-pinning sites that has the potential to increase critical current density beyond present levels. The approach uses internal oxidation of Zr-alloyed Nb tubes to produce Zr oxide particles within the Nb3Sn layer that act as a dispersion of artificial pinning centres (APCs). In this design, SnO2 powder is mixed with Cu5Sn4 powder within the PIT core that supplies the Sn for the A15 reaction with Nb1Zr filament tubes. Initial results show an average grain size of ˜38 nm in the A15 layer, compared to the 90-130 nm of typical APC-free high-J c strands made by conventional PIT or Internal Sn processing. There is a shift in the peak of the pinning force curve from H/H irr of ˜0.2 to ˜0.3 and the pinning force curves can be deconvoluted into grain boundary and point-pinning components, the point-pinning contribution dominating for the APC Nb-1wt%Zr strands.

A punctual flux estimator and reactions rates optimization in neutral particles transport calculus by the Monte Carlo method; Mise au point d'un estimateur ponctuel du flux et des taux de reactions dans les calculs de transport de particules neutres par la methode de monte carlo

Energy Technology Data Exchange (ETDEWEB)

Authier, N

1998-12-01

One of the questions asked in radiation shielding problems is the estimation of the radiation level in particular to determine accessibility of working persons in controlled area (nuclear power plants, nuclear fuel reprocessing plants) or to study the dose gradients encountered in material (iron nuclear vessel, medical therapy, electronics in satellite). The flux and reaction rate estimators used in Monte Carlo codes give average values in volumes or on surfaces of the geometrical description of the system. But in certain configurations, the knowledge of punctual deposited energy and dose estimates are necessary. The Monte Carlo estimate of the flux at a point of interest is a calculus which presents an unbounded variance. The central limit theorem cannot be applied thus no easy confidencelevel may be calculated. The convergence rate is then very poor. We propose in this study a new solution for the photon flux at a point estimator. The method is based on the 'once more collided flux estimator' developed earlier for neutron calculations. It solves the problem of the unbounded variance and do not add any bias to the estimation. We show however that our new sampling schemes specially developed to treat the anisotropy of the photon coherent scattering is necessary for a good and regular behavior of the estimator. This developments integrated in the TRIPOLI-4 Monte Carlo code add the possibility of an unbiased punctual estimate on media interfaces. (author)

A punctual flux estimator and reactions rates optimization in neutral particles transport calculus by the Monte Carlo method; Mise au point d'un estimateur ponctuel du flux et des taux de reactions dans les calculs de transport de particules neutres par la methode de monte carlo

Energy Technology Data Exchange (ETDEWEB)

Authier, N

1998-12-01

One of the questions asked in radiation shielding problems is the estimation of the radiation level in particular to determine accessibility of working persons in controlled area (nuclear power plants, nuclear fuel reprocessing plants) or to study the dose gradients encountered in material (iron nuclear vessel, medical therapy, electronics in satellite). The flux and reaction rate estimators used in Monte Carlo codes give average values in volumes or on surfaces of the geometrical description of the system. But in certain configurations, the knowledge of punctual deposited energy and dose estimates are necessary. The Monte Carlo estimate of the flux at a point of interest is a calculus which presents an unbounded variance. The central limit theorem cannot be applied thus no easy confidencelevel may be calculated. The convergence rate is then very poor. We propose in this study a new solution for the photon flux at a point estimator. The method is based on the 'once more collided flux estimator' developed earlier for neutron calculations. It solves the problem of the unbounded variance and do not add any bias to the estimation. We show however that our new sampling schemes specially developed to treat the anisotropy of the photon coherent scattering is necessary for a good and regular behavior of the estimator. This developments integrated in the TRIPOLI-4 Monte Carlo code add the possibility of an unbiased punctual estimate on media interfaces. (author)

AmeriFlux Data Processing: Integrating automated and manual data management across software technologies and an international network to generate timely data products

Science.gov (United States)

Christianson, D. S.; Beekwilder, N.; Chan, S.; Cheah, Y. W.; Chu, H.; Dengel, S.; O'Brien, F.; Pastorello, G.; Sandesh, M.; Torn, M. S.; Agarwal, D.

2017-12-01

AmeriFlux is a network of scientists who independently collect eddy covariance and related environmental observations at over 250 locations across the Americas. As part of the AmeriFlux Management Project, the AmeriFlux Data Team manages standardization, collection, quality assurance / quality control (QA/QC), and distribution of data submitted by network members. To generate data products that are timely, QA/QC'd, and repeatable, and have traceable provenance, we developed a semi-automated data processing pipeline. The new pipeline consists of semi-automated format and data QA/QC checks. Results are communicated via on-line reports as well as an issue-tracking system. Data processing time has been reduced from 2-3 days to a few hours of manual review time, resulting in faster data availability from the time of data submission. The pipeline is scalable to the network level and has the following key features. (1) On-line results of the format QA/QC checks are available immediately for data provider review. This enables data providers to correct and resubmit data quickly. (2) The format QA/QC assessment includes an automated attempt to fix minor format errors. Data submissions that are formatted in the new AmeriFlux FP-In standard can be queued for the data QA/QC assessment, often with minimal delay. (3) Automated data QA/QC checks identify and communicate potentially erroneous data via online, graphical quick views that highlight observations with unexpected values, incorrect units, time drifts, invalid multivariate correlations, and/or radiation shadows. (4) Progress through the pipeline is integrated with an issue-tracking system that facilitates communications between data providers and the data processing team in an organized and searchable fashion. Through development of these and other features of the pipeline, we present solutions to challenges that include optimizing automated with manual processing, bridging legacy data management infrastructure with

MAGNETIC FLUX CANCELLATION IN ELLERMAN BOMBS

Energy Technology Data Exchange (ETDEWEB)

Reid, A.; Mathioudakis, M.; Nelson, C. J.; Henriques, V. [Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, BT7 1NN, Northern Ireland (United Kingdom); Doyle, J. G. [Armagh Observatory, College Hill, Armagh, BT61 9DG (United Kingdom); Scullion, E. [Trinity College Dublin, College Green, Dublin 2 (Ireland); Ray, T., E-mail: areid29@qub.ac.uk [Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland)

2016-06-01

Ellerman Bombs (EBs) are often found to be co-spatial with bipolar photospheric magnetic fields. We use H α imaging spectroscopy along with Fe i 6302.5 Å spectropolarimetry from the Swedish 1 m Solar Telescope (SST), combined with data from the Solar Dynamic Observatory , to study EBs and the evolution of the local magnetic fields at EB locations. EBs are found via an EB detection and tracking algorithm. Using NICOLE inversions of the spectropolarimetric data, we find that, on average, (3.43 ± 0.49) × 10{sup 24} erg of stored magnetic energy disappears from the bipolar region during EB burning. The inversions also show flux cancellation rates of 10{sup 14}–10{sup 15} Mx s{sup −1} and temperature enhancements of 200 K at the detection footpoints. We investigate the near-simultaneous flaring of EBs due to co-temporal flux emergence from a sunspot, which shows a decrease in transverse velocity when interacting with an existing, stationary area of opposite polarity magnetic flux, resulting in the formation of the EBs. We also show that these EBs can be fueled further by additional, faster moving, negative magnetic flux regions.

Theoretical simulation of the dual-heat-flux method in deep body temperature measurements.

Science.gov (United States)

Huang, Ming; Chen, Wenxi

2010-01-01

Deep body temperature reveals individual physiological states, and is important in patient monitoring and chronobiological studies. An innovative dual-heat-flux method has been shown experimentally to be competitive with the conventional zero-heat-flow method in its performance, in terms of measurement accuracy and step response to changes in the deep temperature. We have utilized a finite element method to model and simulate the dynamic process of a dual-heat-flux probe in deep body temperature measurements to validate the fundamental principles of the dual-heat-flux method theoretically, and to acquire a detailed quantitative description of the thermal profile of the dual-heat-flux probe. The simulation results show that the estimated deep body temperature is influenced by the ambient temperature (linearly, at a maximum rate of 0.03 °C/°C) and the blood perfusion rate. The corresponding depth of the estimated temperature in the skin and subcutaneous tissue layer is consistent when using the dual-heat-flux probe. Insights in improving the performance of the dual-heat-flux method were discussed for further studies of dual-heat-flux probes, taking into account structural and geometric considerations.

Quantum depinning of flux lines from columnar defects

International Nuclear Information System (INIS)

Chudnovsky, E.M.; Ferrera, A.; Vilenkin, A.

1995-01-01

The depinning of a flux line from a columnar defect is studied within the path-integral approach. Instantons of the quantum field theory in 1+1 dimensions are computed for the flux line whose dynamics is dominated by the Magnus force. The universal temperature dependence of the decay rate in the proximity of the critical current is obtained. This problem provides an example of macroscopic quantum tunneling, which is accessible to the direct comparison between theory and experiment

Measurement improvements of heat flux probes for internal combustion engine; Nainen kikan ni okeru netsuryusokukei no kaihatsu to kento

Energy Technology Data Exchange (ETDEWEB)

Tajima, H; Tasaka, H [Miyazaki University, Miyazaki (Japan)

1997-10-01

In heat flux measurement in engines, material properties of a heat flux probe and numerical prediction of those influence have been discussed rather than practical measurement accuracy. This study featured the process for the quantitative examination of heat flux probes. Although the process required direct comparison among all the probes and additional measurements in a constant volume bomb, precision of heat flux measurement was greatly improved so that the essential characteristics of heat transfer in engines can be detected. 9 refs., 8 figs., 1 tab.

Sinking fluxes of minor and trace elements in the North Pacific Ocean measured during the VERTIGO program

Science.gov (United States)

Lamborg, C. H.; Buesseler, K. O.; Lam, P. J.

2008-07-01

As part of the Vertical Transport in the Global Ocean (VERTIGO) program, we collected and analyzed sinking particles using sediment traps at three depths in the oceanic mesopelagic zone and at two biogeochemically contrasting sites (N. Central Pacific at ALOHA; N. Pacific Western Subarctic Gyre at K2). In this paper, we present the results of minor and trace element determinations made on these samples. Minor and trace elements in the sinking material showed 2 trends in flux with depth: increasing and constant. The sinking particulate phase of some elements (Al, Fe, Mn) was dominated by material of lithogenic origin and exhibited flux that was constant with depth and consistent with eolian dust inputs (ALOHA), or increasing in flux with depth as a result of lateral inputs from a shelf (K2). This shelf-derived material also appears to have been confined to very small particles, whose inherent sinking rates are slow, and residence time within the mesopelagic "twilight zone" would be consequently long. Furthermore, the flux of this material did not change with substantial changes in the rain of biogenic material from the surface (K2), suggesting mechanistic decoupling from the flux of organic carbon and macronutrients. Micronutrient (Fe, Co, Zn and Cu) fluxes examined in a 1-D mass balance suggest widely differing sources and sinks in the water column as well as impacts from biological uptake and regeneration. For example, total Fe fluxes into and out of the euphotic zone appeared to be dominated by lithogenic material and far exceed biological requirements. The export flux of Fe, however, appeared to be balanced by the eolian input of soluble Fe. For Zn and Cu, the situation is reversed, with atmospheric inputs insufficient to support fluxes, and the cycling therefore dominated by the draw down of an internal pool. For Co, the situation lies in between, with important, but ultimately insufficient atmospheric inputs.

A conceptual high flux reactor design with scope for use in ADS ...

Indian Academy of Sciences (India)

By design the flux level in the seed fuel has been kept lower than in the high flux trap zones so that the burning rate of the seed is reduced. Another important objective of the design is to maximize the time interval of refueling. As against a typical refueling interval of a few weeks in such high flux reactor cores, it is desired to ...

Event-driven sediment flux in Hueneme and Mugu submarine canyons, southern California

Science.gov (United States)

Xu, J. P.; Swarzenski, P.W.; Noble, M.; Li, A.-C.

2010-01-01

Vertical sediment fluxes and their dominant controlling processes in Hueneme and Mugu submarine canyons off south-central California were assessed using data from sediment traps and current meters on two moorings that were deployed for 6 months during the winter of 2007. The maxima of total particulate flux, which reached as high as 300+ g/m2/day in Hueneme Canyon, were recorded during winter storm events when high waves and river floods often coincided. During these winter storms, wave-induced resuspension of shelf sediment was a major source for the elevated sediment fluxes. Canyon rim morphology, rather than physical proximity to an adjacent river mouth, appeared to control the magnitude of sediment fluxes in these two submarine canyon systems. Episodic turbidity currents and internal bores enhanced sediment fluxes, particularly in the lower sediment traps positioned 30 m above the canyon floor. Lower excess 210Pb activities measured in the sediment samples collected during periods of peak total particulate flux further substantiate that reworked shelf-, rather than newly introduced river-borne, sediments supply most of the material entering these canyons during storms.

Role of magnetic flux perturbations in confinement bifurcations in TUMAN-3M

International Nuclear Information System (INIS)

Lebedev, S.V.; Andreiko, M.V.; Askinazi, L.G.

2003-01-01

Poloidal magnetic flux variations in the small tokamak TUMAN-3M allowed observation of transitions between different confinement modes. The possibility of switching on/off the ohmic H-mode by edge poloidal magnetic flux perturbations has been found. The flux perturbations were created by fast current ramp up/down or by magnetic compression/decompression produced by fast increase/decrease in the toroidal magnetic field. It was found that positive flux perturbations (current ramp-up and magnetic compression scenarios) are useful means of H-mode triggering. If a negative flux perturbation (current ramp-down or magnetic decompression) is applied, the H-mode terminated. Various mechanisms involved in the L-H and H-L transition physics in the flux perturbation experiments were analyzed. The experimental observations of the transitions between confinement modes might be understood in terms of the model of a sheared radial electric field generation, which takes into account the electron Ware drift in a perturbed longitudinal electric field. Another scenario of improved confinement was observed in the initial phase of an ohmic discharge, when change in the poloidal flux is associated with current ramp-up. Variation of the rates of current ramp-up and working gas puffing in the beginning of a discharge resulted in a fast increase in the electron temperature near the axis. The increase correlates with low m/n MHD mode growth. The observed core electron confinement improvement is apparently connected with the rate of current ramp. Deviation from the optimal rate results in disappearance of the improvement. The role of magnetic shear profile and rational magnetic surfaces in the core electron confinement improvement in the initial phase of ohmic discharges is discussed. (author)

A process-based 222radon flux map for Europe and its comparison to long-term observations

Science.gov (United States)

Karstens, U.; Schwingshackl, C.; Schmithüsen, D.; Levin, I.

2015-11-01

Detailed 222radon (222Rn) flux maps are an essential pre-requisite for the use of radon in atmospheric transport studies. Here we present a high-resolution 222Rn flux map for Europe, based on a parameterization of 222Rn production and transport in the soil. The 222Rn exhalation rate is parameterized based on soil properties, uranium content, and modelled soil moisture from two different land-surface reanalysis data sets. Spatial variations in exhalation rates are primarily determined by the uranium content of the soil, but also influenced by soil texture and local water-table depth. Temporal variations are related to soil moisture variations as the molecular diffusion in the unsaturated soil zone depends on available air-filled pore space. The implemented diffusion parameterization was tested against campaign-based 222Rn soil profile measurements. Monthly 222Rn exhalation rates from European soils were calculated with a nominal spatial resolution of 0.083° × 0.083° and compared to long-term direct measurements of 222Rn exhalation rates in different areas of Europe. The two realizations of the 222Rn flux map, based on the different soil moisture data sets, both realistically reproduce the observed seasonality in the fluxes but yield considerable differences for absolute flux values. The mean 222Rn flux from soils in Europe is estimated to be 10 mBq m-2 s-1 (ERA-Interim/Land soil moisture) or 15 mBq m-2 s-1 (GLDAS (Global Land Data Assimilation System) Noah soil moisture) for the period 2006-2010. The corresponding seasonal variations with low fluxes in winter and high fluxes in summer range in the two realizations from ca. 7 to ca. 14 mBq m-2 s-1 and from ca. 11 to ca. 20 mBq m-2 s-1, respectively. These systematic differences highlight the importance of realistic soil moisture data for a reliable estimation of 222Rn exhalation rates. Comparison with observations suggests that the flux estimates based on the GLDAS Noah soil moisture model on average better

A process-based 222radon flux map for Europe and its comparison to long-term observations

International Nuclear Information System (INIS)

Karstens, U.; Schwingshackl, C.; Schmithuesen, D.; Levin, I.

2015-01-01

Detailed 222 radon ( 222 Rn) flux maps are an essential pre-requisite for the use of radon in atmospheric transport studies. Here we present a high-resolution 222 Rn flux map for Europe, based on a parameterization of 222 Rn production and transport in the soil. The 222 Rn exhalation rate is parameterized based on soil properties, uranium content, and modelled soil moisture from two different land-surface reanalysis data sets. Spatial variations in exhalation rates are primarily determined by the uranium content of the soil, but also influenced by soil texture and local water-table depth. Temporal variations are related to soil moisture variations as the molecular diffusion in the unsaturated soil zone depends on available air-filled pore space. The implemented diffusion parameterization was tested against campaign-based 222 Rn soil profile measurements. Monthly 222 Rn exhalation rates from European soils were calculated with a nominal spatial resolution of 0.083 x 0.083 and compared to long-term direct measurements of 222 Rn exhalation rates in different areas of Europe. The two realizations of the 222 Rn flux map, based on the different soil moisture data sets, both realistically reproduce the observed seasonality in the fluxes but yield considerable differences for absolute flux values. The mean 222 Rn flux from soils in Europe is estimated to be 10 mBq m -2 s -1 (ERA-Interim/Land soil moisture) or 15 mBq m -2 s -1 (GLDAS (Global Land Data Assimilation System) Noah soil moisture) for the period 2006-2010. The corresponding seasonal variations with low fluxes in winter and high fluxes in summer range in the two realizations from ca. 7 to ca. 14 mBq m -2 s -1 and from ca. 11 to ca. 20 mBq m -2 s -1 , respectively. These systematic differences highlight the importance of realistic soil moisture data for a reliable estimation of 222 Rn exhalation rates. Comparison with observations suggests that the flux estimates based on the GLDAS Noah soil moisture model on

Flux expulsion and trapping in rotating discs of type II superconductors

International Nuclear Information System (INIS)

Boyer, R.; Leblanc, M.A.R.

1977-01-01

The magnetic flux rotating in step with a type II superconducting disc is measured with orthogonal pick up coils for various previous magnetic histories vs H 0 applied at right angles to the axis of rotation. For some initial magnetic states, flux expulsion, independent of the rate of rotation, occurs during the initial rotation. A simple model where flux lines leave the specimen against the magnetic pressure in the active region accounts for the observations. (author)

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

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)

Low internal pressure in femtoliter water capillary bridges reduces evaporation rates.

Science.gov (United States)

Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

2016-03-01

Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges.

Low internal pressure in femtoliter water capillary bridges reduces evaporation rates

Science.gov (United States)

Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

2016-01-01

Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges. PMID:26928329

Boiling-Water Reactor internals aging degradation study

International Nuclear Information System (INIS)

Luk, K.H.

1993-09-01

This report documents the results of an aging assessment study for boiling water reactor (BWR) internals. Major stressors for BWR internals are related to unsteady hydrodynamic forces generated by the primary coolant flow in the reactor vessel. Welding and cold-working, dissolved oxygen and impurities in the coolant, applied loads and exposures to fast neutron fluxes are other important stressors. Based on results of a component failure information survey, stress corrosion cracking (SCC) and fatigue are identified as the two major aging-related degradation mechanisms for BWR internals. Significant reported failures include SCC in jet-pump holddown beams, in-core neutron flux monitor dry tubes and core spray spargers. Fatigue failures were detected in feedwater spargers. The implementation of a plant Hydrogen Water Chemistry (HWC) program is considered as a promising method for controlling SCC problems in BWR. More operating data are needed to evaluate its effectiveness for internal components. Long-term fast neutron irradiation effects and high-cycle fatigue in a corrosive environment are uncertainty factors in the aging assessment process. BWR internals are examined by visual inspections and the method is access limited. The presence of a large water gap and an absence of ex-core neutron flux monitors may handicap the use of advanced inspection methods, such as neutron noise vibration measurements, for BWR

The influence of measurement and relaxation time on flux jumps in high temperature superconductors

International Nuclear Information System (INIS)

Yang Xiaobin; Zhou Youhe; Tu Shandong

2010-01-01

The influence of the magnetization and relaxation time on flux jumps in high temperature superconductors (HTSC) under varying magnetic field is studied using the fundamental electromagnetic field equations and the thermal diffusion equation; temperature variety corresponding to flux jump is also discussed. We find that for a low sweep rate of the applied magnetic field, the measurement and relaxation times can reduce flux jump and to constrain the number of flux jumps, even stabilizing the HTSC, since much heat produced by the motion of magnetic flux can transfer into coolant during the measurement and relaxation times. As high temperature superconductors are subjected to a high sweep rate or a strong pulsed magnetic field, magnetization undergoes from stability or oscillation to jump for different pause times. And the period of temperature oscillation is equal to the measurement and relaxation time.

Methane and Carbon Dioxide Concentrations and Fluxes in Amazon Floodplains

Science.gov (United States)

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

2016-12-01

Field studies on the central Amazon floodplain in representative aquatic habitats (open water, flooded forests, floating macrophytes) combine measurements of methane and carbon dioxide concentrations and fluxes to the atmosphere over diel and seasonal times with deployment of meteorological sensors and high-resolution thermistors and dissolved oxygen sondes. A cavity ringdown spectrometer is used to determine gas concentrations, and floating chambers and bubble collectors are used to measure fluxes. To further understand fluxes, we measured turbulence as rate of dissipation of turbulent kinetic energy based on microstructure profiling. These results allow calculations of vertical mixing within the water column and of air-water exchanges using surface renewal models. Methane and carbon dioxide fluxes varied as a function of season, habitat and water depth. High CO2 fluxes at high water are related to high pCO2; low pCO2 levels at low water result from increased phytoplankton uptake. CO2 fluxes are highest at turbulent open water sites, and pCO2 is highest in macrophyte beds. Fluxes and pCH4 are high in macrophyte beds.

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

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.

INAA analysis of rocks: A routine method using Fe as an internal flux monitor

International Nuclear Information System (INIS)

Kay, R.W.; Kay, S. Mahlburg

1992-01-01

Over the past decade at Cornell, trace elements in over 2500 rocks have been analyzed by INAA. The samples, mainly volcanic rocks, have known concentrations of major elements (e.g. Si, Ti, Al, Mg, Ca, K, Fe, Na) and the last two of these (Fe and Na) are also determined by activation, using rock standards (e.g. USGS standards BCRl, BHVO, etc.). Differences between Fe determined by INAA and that determined as a part of the major element analysis are mainly attributed to volatile (H 2 O, CO 2 ) loss (especially when major element analyses were done by electron microprobe on fused powders, whereas the INAA analyses were done on the powders), and to flux variability during irradiation. Instead of reporting two values for Fe we use Fe as an internal flux monitor, with Na and the trace elements being reported relative to the given Fe value. The ratio Na/Fe is used as a sensitive check on the identity of the sample and as a monitor of alkali loss affecting the major element analysis. Other than this modification (Kay et aL 1987, also reported in Chappell and Hergt, 1989) we use an INAA method similar to mat practiced by many labs. Powdered samples (about 0.5 g) are sealed in high-purity silica tubes and irradiated in the Cornell Triga reactor. Samples are counted for a minimum of 2 hours (up to 10 hours) 7 and 40 days after irradiation. Data are reduced using a program written at Cornell, with peak and background regions that have been checked for interferences. Corrections are routinely applied for Ce (Fe), Nd (Br), Tb (Th), Eu (Ba), Lu (U), and Yb (Th) (interference is from element in parentheses). A U fission yield correction is applied to La, Ce, Nd, and Ba. A correction for Ta introduced by grinding in WC containers can be made using known Ta/W ratios in the grinding containers. The correction amounted to 10-20% of the Ta gross peak. Recently, samples have been prepared in a ceramic grinding containers; for these, no Ta correction is needed. Trace elements determined

Monitoring Forest Carbon Stocks and Fluxes in the Congo Basin

OpenAIRE

2010-01-01

The Central African Forests Commission (COMIFAC) and its partners (OFAC, USAID, EC-JRC, OSFAC, WWF, WRI, WCS, GOFC-GOLD, START, UN-FAO) organized an international conference on "Monitoring of Carbon stocks and fluxes in the Congo Basin" in Brazzaville, Republic of Congo, 2-4 February 2010. The conference brought together leading international specialists to discuss approaches for quantifying stocks and flows of carbon in tropical forests of the Congo Basin. The conference provided a unique op...

High Upward Fluxes of Formic Acid from a Boreal Forest Canopy

Science.gov (United States)

Schobesberger, Siegfried; Lopez-Hilifiker, Felipe D.; Taipale, Ditte; Millet, Dylan B.; D'Ambro, Emma L.; Rantala, Pekka; Mammarella, Ivan; Zhou, Putian; Wolfe, Glenn M.; Lee, Ben H.;

Continuous In Situ Measurements of Near Bottom Chemistry and Sediment-Water Fluxes with the Chimney Sampler Array (CSA)

Science.gov (United States)

Martens, C. S.; Mendlovitz, H. P.; White, B. L.; Hoer, D.; Sleeper, K.; Chanton, J.; Wilson, R.; Lapham, L.

2011-12-01

The Chimney Sampler Array (CSA) was designed to measure in situ chemical and physical parameters within the benthic boundary layer plus methane and oxygen sediment-water chemical fluxes at upper slope sites in the northern Gulf of Mexico. The CSA can monitor temporal changes plus help to evaluate oceanographic and sub-seafloor processes that can influence the formation and stability of gas hydrates in underlying sediments. The CSA consists of vertical cylinders (chimneys) equipped with internal chemical sensors and with laboratory flume-calibrated washout rates. Chimney washout rates multiplied by chimney mean versus ambient concentrations allow calculation of net O2 and methane sediment-water fluxes. The CSA is emplaced on the seafloor by a ROVARD lander using a ROV for chimney deployments. The CSA presently includes two 30 cm diameter by 90 cm length cylinders that seal against the sediment with lead pellet beanbags; within each chimney cylinder are optode, conductivity and methane sensors. The CSA's data logger platform also includes pressure and turbidity sensors external to the chimneys along with an acoustic Doppler current meter to measure temporal variation in ambient current velocity and direction. The CSA was deployed aboard a ROVARD lander on 9/13/2010 in the northern Gulf of Mexico (Lat. 28 51.28440, Long. 088 29.39421) on biogeochemically active sediments within Block MC-118. A ROV was utilized for chimney deployment away from the ROVARD lander. The CSA monitored temporal changes in water column physical parameters, obtained near-bottom chemical data to compare with pore fluid and sediment core measurements and measured temporal variability in oxygen and methane sediment-water fluxes at two closely spaced stations at MC-118. A continuous, three-week data set was obtained that revealed daily cycles in chemical parameters and episodic flux events. Lower than ambient chimney dissolved O2 concentrations controlled by temporal variability in washout rates

Metabolic Flux Distribution during Defatting of Steatotic Human Hepatoma (HepG2 Cells

Directory of Open Access Journals (Sweden)

Gabriel Yarmush

2016-01-01

Full Text Available Methods that rapidly decrease fat in steatotic hepatocytes may be helpful to recover severely fatty livers for transplantation. Defatting kinetics are highly dependent upon the extracellular medium composition; however, the pathways involved are poorly understood. Steatosis was induced in human hepatoma cells (HepG2 by exposure to high levels of free fatty acids, followed by defatting using plain medium containing no fatty acids, or medium supplemented with a cocktail of defatting agents previously described before. We measured the levels of 28 extracellular metabolites and intracellular triglyceride, and fed the data into a steady-state mass balance model to estimate strictly intracellular fluxes. We found that during defatting, triglyceride content decreased, while beta-oxidation, the tricarboxylic acid cycle, and the urea cycle increased. These fluxes were augmented by defatting agents, and even more so by hyperoxic conditions. In all defatting conditions, the rate of extracellular glucose uptake/release was very small compared to the internal supply from glycogenolysis, and glycolysis remained highly active. Thus, in steatotic HepG2 cells, glycolysis and fatty acid oxidation may co-exist. Together, these pathways generate reducing equivalents that are supplied to mitochondrial oxidative phosphorylation.

The Koukopoulos Mixed Depression Rating Scale (KMDRS): An International Mood Network (IMN) validation study of a new mixed mood rating scale.

Science.gov (United States)

Sani, Gabriele; Vöhringer, Paul A; Barroilhet, Sergio A; Koukopoulos, Alexia E; Ghaemi, S Nassir

2018-05-01

It has been proposed that the broad major depressive disorder (MDD) construct is heterogenous. Koukopoulos has provided diagnostic criteria for an important subtype within that construct, "mixed depression" (MxD), which encompasses clinical pictures characterized by marked psychomotor or inner excitation and rage/anger, along with severe depression. This study provides psychometric validation for the first rating scale specifically designed to assess MxD symptoms cross-sectionally, the Koukopoulos Mixed Depression Rating Scale (KMDRS). 350 patients from the international mood network (IMN) completed three rating scales: the KMDRS, Montgomery-Asberg Depression Rating Scale (MADRS) and Young Mania Rating Scale (YMRS). KMDRS' psychometric properties assessed included Cronbach's alpha, inter-rater reliability, factor analysis, predictive validity, and Receiver Operator Curve analysis. Internal consistency (Cronbach's alpha = 0.76; 95% CI 0.57, 0.94) and interrater reliability (kappa = 0.73) were adequate. Confirmatory factor analysis identified 2 components: anger and psychomotor excitation (80% of total variance). Good predictive validity was seen (C-statistic = 0.82 95% CI 0.68, 0.93). Severity cut-off scores identified were as follows: none (0-4), possible (5-9), mild (10-15), moderate (16-20) and severe (> 21) MxD. Non DSM-based diagnosis of MxD may pose some difficulties in the initial use and interpretation of the scoring of the scale. Moreover, the cross-sectional nature of the evaluation does not verify the long-term stability of the scale. KMDRS was a reliable and valid instrument to assess MxD symptoms. Copyright © 2018 Elsevier B.V. All rights reserved.

Magnetic relaxation, flux pinning and critical currents in superconductors

International Nuclear Information System (INIS)

Lichtenberger, K.S.

1991-01-01

A systematic study of the magnetic flux pinning properties in superconductors has been undertaken in an attempt to understand the differences between the flux creep behavior of classical superconductors and high-temperature superconductors (HTSC's). In HTSC's, the ratio of the effective flux pinning energy to the thermal energy, U 0 /kT, is much smaller than that of conventional superconductors, often approaching unity. This results in much larger creep rates in HTSC's than in conventional superconductors. It is necessary to find suitable models that describe flux creep in both classical superconductors and HTSC's. Results show that while these two classes of materials are quantitatively very different, a single pinning barrier mode adequately describes both, within the proper region of the H-T plane. The model is applied to a variety of superconductors and the results are contrasted. Although the H-T plane appears to be very different HTSC's than for conventional superconductors, qualitatively the same physics describes both. In HTSC's, near the upper critical field there exists a relatively wide region of superconducting fluctuations, followed successively by regions of thermodynamic reversibility, thermally assisted flux, flux creep, and finally rigid flux lattice where little, if any, motion of the flux lattice occurs. All of these regions are also present in conventional superconductors, but often much more difficult, especially the irreversibility transition and the fluctuation region. The central finding of the flux creep analysis is that the region of flux creep is defined as a band in the H-T plane in which 2 ≤ U 0 /kT ≤ 100, and that the flux creep model applies best within this band

An Assessment of the Internal Rating Based Approach in Basel II

OpenAIRE

Simone Varotto

2008-01-01

The new bank capital regulation commonly known as Basel II includes a internal rating based approach (IRB) to measuring credit risk in bank portfolios. The IRB relies on the assumptions that the portfolio is fully diversified and that systematic risk is driven by one common factor. In this work we empirically investigate the impact of these assumptions by comparing the risk measures produced by the IRB with those of a more general credit risk model that allows for multiple systematic risk fac...

Seasonal and interannual variability in deep ocean particle fluxes at the Oceanic Flux Program (OFP)/Bermuda Atlantic Time Series (BATS) site in the western Sargasso Sea near Bermuda

Science.gov (United States)

Conte, Maureen H.; Ralph, Nate; Ross, Edith H.

consistent with a model of rapid particle turnover and material scavenging from the suspended pool during new particle formation. We suggest that much of the deep mass flux is generated in situ by deep-dwelling zooplankton, and that mass flux, as well as scavenging of suspended materials from the deep water column, varies in proportion to changes in grazer activity. Labile, very rapidly sinking aggregates (e.g., salp fecal material) arriving in the bathypelagic zone within days of their upper ocean production may act to stimulate zooplankton grazing rates and increase large particle production and deep mass flux days to weeks in advance of the arrival of bulk of surface-produced material. This process could reconcile mean particle sinking rate estimates with the phase coherence observed between upper and deep ocean mass fluxes.

PREFACE: International Workshop on Multi-Rate Processes and Hysteresis

Science.gov (United States)

Mortell, Michael P.; O'Malley, Robert E.; Pokrovskii, Alexei; Rachinskii, Dmitrii; Sobolev, Vladimir A.

2008-07-01

We are interested in singular perturbation problems and hysteresis as common strongly nonlinear phenomena that occur in many industrial, physical and economic systems. The wording `strongly nonlinear' means that linearization will not encapsulate the observed phenomena. Often these two types of phenomena are manifested for different stages of the same or similar processes. A number of fundamental hysteresis models can be considered as limit cases of time relaxation processes, or admit an approximation by a differential equation which is singular with respect to a particular parameter. However, the amount of interaction between practitioners of theories of systems with time relaxation and systems with hysteresis (and between the `relaxation' and `hysteresis' research communities) is still low, and cross-fertilization is small. In recent years Ireland has become a home for a series of prestigious International Workshops in Singular Perturbations and Hysteresis: International Workshop on Multi-rate Processes and Hysteresis (University College Cork, Ireland, 3-8 April 2006). Proceedings are published in Journal of Physics: Conference Series, volume 55. See further information at http://euclid.ucc.ie/murphys2008.htm International Workshop on Hysteresis and Multi-scale Asymptotics (University College Cork, Ireland, 17-21 March 2004). Proceedings are published in Journal of Physics: Conference Series, volume 22. See further information at http://euclid.ucc.ie/murphys2006.htm International Workshop on Relaxation Oscillations and Hysteresis (University College Cork, Ireland, 1-6 April 2002). The related collection of invited lectures, was published as a volume Singular Perturbations and Hysteresis, SIAM, Philadelphia, 2005. See further information at http://euclid.ucc.ie/hamsa2004.htm International Workshop on Geometrical Methods of Nonlinear Analysis and Semiconductor Laser Dynamics (University College Cork, Ireland, 5-5 April 2001). A collection of invited papers has been

Fast neutron flux and intracranial dose distribution at a neutron irradiation facility

International Nuclear Information System (INIS)

Matsumoto, Tetsuo; Aizawa, Otohiko; Nozaki, Tetsuya

1981-01-01

A head phantom filled with water was used to measure the fast neutron flux using 115 In(n, n')sup(115m)In and 103 Rh(n, n')sup(103m)Rh reactions. γ-ray from sup(115m)In and x-ray from sup(103m)Rh were detected by a Ge(Li) and a Na(Tl)I counter, respectively. TLD was used to investigate the γ-dose rate distribution inside the phantom. Flux of fast neutron inside the phantom was about 1 x 10 6 n/cm 2 sec, which was 3 order smaller than that of thermal neutron. The fast neutron flux decreased to 1/10 at 15 cm depth, and γ-dose rate was about 200 R/h at 100 kW inside the phantom. Total dose at the surface was 350 rad/h, to which, fast neutrons contributed more than γ-rays. The rate of fast neutron dose was about 10% of thermal neutron's in Kerma dose unit (rad), however, the rate was highly dependent on RBE value. (Nakanishi, T.)

Neutron flux control systems validation

International Nuclear Information System (INIS)

Hascik, R.

2003-01-01

In nuclear installations main requirement is to obtain corresponding nuclear safety in all operation conditions. From the nuclear safety point of view is commissioning and start-up after reactor refuelling appropriate period for safety systems verification. In this paper, methodology, performance and results of neutron flux measurements systems validation is presented. Standard neutron flux measuring chains incorporated into the reactor protection and control system are used. Standard neutron flux measuring chain contains detector, preamplifier, wiring to data acquisition unit, data acquisition unit, wiring to display at control room and display at control room. During reactor outage only data acquisition unit and wiring and displaying at reactor control room is verified. It is impossible to verify detector, preamplifier and wiring to data acquisition recording unit during reactor refuelling according to low power. Adjustment and accurate functionality of these chains is confirmed by start-up rate (SUR) measurement during start-up tests after refuelling of the reactors. This measurement has direct impact to nuclear safety and increase operational nuclear safety level. Briefly description of each measuring system is given. Results are illustrated on measurements performed at Bohunice NPP during reactor start-up tests. Main failures and their elimination are described (Authors)

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

Observation of magnetic flux generated spontaneously during a rapid quench of superconducting films

International Nuclear Information System (INIS)

Maniv, A.; Polturak, E.; Koren, G.

2003-01-01

We report observations of spontaneous formation of magnetic flux lines during a rapid quench of YBa 2 Cu 3 O 7-δ films through T c . This effect is predicted according to the Kibble-Zurek mechanism of creation of topological defects of the order parameter during a symmetry-breaking phase transition. Our previous experiment, at a quench rate of 20 K/s, gave null results. In the present experiment, the quench rate was increased to >10 8 K/s. The amount of spontaneous flux increases weakly with the cooling rate

General correlation for prediction of critical heat flux ratio in water cooled channels

Energy Technology Data Exchange (ETDEWEB)

Pernica, R.; Cizek, J.

1995-09-01

The paper present the general empirical Critical Heat Flux Ration (CHFR) correlation which is valid for vertical water upflow through tubes, internally heated concentric annuli and rod bundles geometries with both wide and very tight square and triangular rods lattices. The proposed general PG correlation directly predicts the CHFR, it comprises axial and radial non-uniform heating, and is valid in a wider range of thermal hydraulic conditions than previously published critical heat flux correlations. The PG correlation has been developed using the critical heat flux Czech data bank which includes more than 9500 experimental data on tubes, 7600 data on rod bundles and 713 data on internally heated concentric annuli. Accuracy of the CHFR prediction, statistically assessed by the constant dryout conditions approach, is characterized by the mean value nearing 1.00 and the standard deviation less than 0.06. Moverover, a subchannel form of the PG correlations is statistically verified on Westinghouse and Combustion Engineering rod bundle data bases, i.e. more than 7000 experimental CHF points of Columbia University data bank were used.

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

PC based system for absolute neutron flux-spectrum measurements. Final report for the period 1 April 1994 - 15 December 1997

International Nuclear Information System (INIS)

Dobrea, D.

1998-01-01

When measuring absolute neutron flux-spectra, thin detector foils are irradiated in a neutron field. The absolute activity of isotopes generated by activation or fission reactions (fission products) is then measured, using an efficiency calibrated high resolution gamma-ray spectroscopy system, and the absolute reaction rates for their production is determined. Finally the flux-spectrum is determined based upon the reaction rate values. A general method to obtain flux-spectra from the reaction rate is the unfolding method. The above process involves computations of photopeak area, reaction rate, flux perturbation corrections and flux-spectrum. The PC's are well suited for the data processing system outlined above. Using available interfaces, the PC's can be involved even in the data acquisition. Graphical facilities allow decision upon the data processing flow

Investigation of the low flux servo-controlled limit of a co-phased interferometer

Science.gov (United States)

Damé, Luc; Derrien, Marc; Kozlowski, Mathias; Merdjane, Mohamed

2018-04-01

This paper, "Investigation of the low flux servo-controlled limit of a co-phased interferometer," was presented as part of International Conference on Space Optics—ICSO 1997, held in Toulouse, France.

Dryout-type critical heat flux in vertical upward annular flow: effects of entrainment rate, initial entrained fraction and diameter

Science.gov (United States)

Wu, Zan; Wadekar, Vishwas; Wang, Chenglong; Sunden, Bengt

2018-01-01

This study aims to reveal the effects of liquid entrainment, initial entrained fraction and tube diameter on liquid film dryout in vertical upward annular flow for flow boiling. Entrainment and deposition rates of droplets were included in mass conservation equations to estimate the local liquid film mass flux in annular flow, and the critical vapor quality at dryout conditions. Different entrainment rate correlations were evaluated using flow boiling data of water and organic liquids including n-pentane, iso-octane and R134a. Effect of the initial entrained fraction (IEF) at the churn-to-annular flow transition was also investigated. A transitional Boiling number was proposed to separate the IEF-sensitive region at high Boiling numbers and the IEF-insensitive region at low Boiling numbers. Besides, the diameter effect on dryout vapor quality was studied. The dryout vapor quality increases with decreasing tube diameter. It needs to be pointed out that the dryout characteristics of submillimeter channels might be different because of different mechanisms of dryout, i.e., drying of liquid film underneath long vapor slugs and flow boiling instabilities.

Microtopography and methane flux in boreal peatlands, northern Ontario, Canada

International Nuclear Information System (INIS)

Bubier, J.; Costello, A.; Moore, T.R.; Roulet, N.T.; Savage, K.

1993-01-01

Peatlands act as a major sink of carbon dioxide and a source of methane. Fluxes of methane were measured by a static chamber technique at hummock, hollow, and lawn microtopographic locations in 12 peatland sites near Cochrane, northern Ontario, from May to October 1991. Average fluxes (mg/m 2 /d) were 2.3 at hummocks, 44.4 at hollows, and 15.6 at lawns. Methane flux was negatively correlated with average water table position based on the 36 locations, with hummocks having a smaller flux than hollows or lawns, where the water table depth was <25 cm. Peat samples from a bog hummock and hollow failed to produce methane during anaerobic incubations in the laboratory; samples from a poor fen hollow produced <1.4 μg/g/d. The production decreased with depth but was greater than the rates observed during incubation of samples from an adjacent hummock. Rates of methane consumption during aerobic incubations ranged from 1 to 55 μg/g/d and were greatest in the surface layers and decreased with depth. Differences in methane emissions between hummocks and hollows appear to be controlled primarily by greater methane production rates in hollows compared with hummocks. Of secondary importance are the capacity of the peat profiles to consume methane during its transport to the peat surface and warmer temperatures at the water table beneath hollows compared with hummocks. 29 refs., 4 figs., 2 tabs

Supersymmetry breaking and α'-corrections to flux induced potentials

International Nuclear Information System (INIS)

Becker, Katrin; Becker, Melanie; Haack, Michael; Louis, Jan

2002-01-01

We obtain the vacuum solutions for M-theory compactified on eight-manifolds with non-vanishing four-form flux by analyzing the scalar potential appearing in the three-dimensional theory. Many of these vacua are not supersymmetric and yet have a vanishing three-dimensional cosmological constant.We show that in the context of type-IIB compactifications on Calabi-Yau threefolds with fluxes and external brane sources α'-corrections generate a correction to the supergravity potential proportional to the Euler number of the internal manifold which spoils the no-scale structure appearing in the classical potential. This indicates that α'-corrections may indeed lead to a stabilization of the radial modulus appearing in these compactifications. (author)

Solar neutrino flux at keV energies

Science.gov (United States)

Vitagliano, Edoardo; Redondo, Javier; Raffelt, Georg

2017-12-01

We calculate the solar neutrino and antineutrino flux in the keV energy range. The dominant thermal source processes are photo production (γ e→ e νbar nu), bremsstrahlung (e+Ze→ Ze+e+νbar nu), plasmon decay (γ→νbar nu), and νbar nu emission in free-bound and bound-bound transitions of partially ionized elements heavier than hydrogen and helium. These latter processes dominate in the energy range of a few keV and thus carry information about the solar metallicity. To calculate their rate we use libraries of monochromatic photon radiative opacities in analogy to a previous calculation of solar axion emission. Our overall flux spectrum and many details differ significantly from previous works. While this low-energy flux is not measurable with present-day technology, it could become a significant background for future direct searches for keV-mass sterile neutrino dark matter.

The Gravity of Dark Vortices: Effective Field Theory for Branes and Strings Carrying Localized Flux

CERN Document Server

Burgess, C P; Williams, M

2015-01-01

A Nielsen-Olesen vortex usually sits in an environment that expels the flux that is confined to the vortex, so flux is not present both inside and outside. We construct vortices for which this is not true, where the flux carried by the vortex also permeates the `bulk' far from the vortex. The idea is to mix the vortex's internal gauge flux with an external flux using off-diagonal kinetic mixing. Such `dark' vortices could play a phenomenological role in models with both cosmic strings and a dark gauge sector. When coupled to gravity they also provide explicit ultra-violet completions for codimension-two brane-localized flux, which arises in extra-dimensional models when the same flux that stabilizes extra-dimensional size is also localized on space-filling branes situated around the extra dimensions. We derive simple formulae for observables such as defect angle, tension, localized flux and on-vortex curvature when coupled to gravity, and show how all of these are insensitive to much of the microscopic detail...

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.

Crystallization kinetics of Ga metallic nano-droplets under As flux

International Nuclear Information System (INIS)

Bietti, S; Somaschini, C; Sanguinetti, S

2013-01-01

We present an experimental investigation of the crystallization dynamics of Ga nano-droplets under As flux. The transformation of the metallic Ga contained in the droplets into a GaAs nano-island proceeds by increasing the size of a tiny ring of GaAs which is formed just after the Ga deposition at the rim of a droplet. The GaAs crystallization rate depends linearly on the liquid–solid interface area. The maximum growth rate is set by the As flux impinging on the droplet, thus showing an efficient As incorporation and transport despite the predicted low solubility of the As in metallic Ga at the crystallization temperatures. (paper)

Small-scale experimental study of vaporization flux of liquid nitrogen released on water.

Science.gov (United States)

Gopalaswami, Nirupama; Olewski, Tomasz; Véchot, Luc N; Mannan, M Sam

2015-10-30

A small-scale experimental study was conducted using liquid nitrogen to investigate the convective heat transfer behavior of cryogenic liquids released on water. The experiment was performed by spilling five different amounts of liquid nitrogen at different release rates and initial water temperatures. The vaporization mass fluxes of liquid nitrogen were determined directly from the mass loss measured during the experiment. A variation of initial vaporization fluxes and a subsequent shift in heat transfer mechanism were observed with changes in initial water temperature. The initial vaporization fluxes were directly dependent on the liquid nitrogen spill rate. The heat flux from water to liquid nitrogen determined from experimental data was validated with two theoretical correlations for convective boiling. It was also observed from validation with correlations that liquid nitrogen was found to be predominantly in the film boiling regime. The substantial results provide a suitable procedure for predicting the heat flux from water to cryogenic liquids that is required for source term modeling. Copyright © 2015 Elsevier B.V. All rights reserved.

Mixing in heterogeneous internally-heated convection

Science.gov (United States)

Limare, A.; Kaminski, E. C.; Jaupart, C. P.; Farnetani, C. G.; Fourel, L.; Froment, M.

2017-12-01

Past laboratory experiments of thermo chemical convection have dealt with systems involving fluids with different intrinsic densities and viscosities in a Rayleigh-Bénard setup. Although these experiments have greatly improved our understanding of the Earth's mantle dynamics, they neglect a fundamental component of planetary convection: internal heat sources. We have developed a microwave-based method in order to study convection and mixing in systems involving two layers of fluid with different densities, viscosities, and internal heat production rates. Our innovative laboratory experiments are appropriate for the early Earth, when the lowermost mantle was likely enriched in incompatible and heat producing elements and when the heat flux from the core probably accounted for a small fraction of the mantle heat budget. They are also relevant to the present-day mantle if one considers that radioactive decay and secular cooling contribute both to internal heating. Our goal is to quantify how two fluid layers mix, which is still very difficult to resolve accurately in 3-D numerical calculations. Viscosities and microwave absorptions are tuned to achieve high values of the Rayleigh-Roberts and Prandtl numbers relevant for planetary convection. We start from a stably stratified system where the lower layer has higher internal heat production and density than the upper layer. Due to mixing, the amount of enriched material gradually decreases to zero over a finite time called the lifetime. Based on more than 30 experiments, we have derived a scaling law that relates the lifetime of an enriched reservoir to the layer thickness ratio, a, to the density and viscosity contrasts between the two layers, and to their two different internal heating rates in the form of an enrichment factor beta=1+2*a*H1/H, where H1 is the heating rate of the lower fluid and H is the average heating rate. We find that the lifetime of the lower enriched reservoir varies as beta**(-7/3) in the low

Reduced TCA Flux in Diabetic Myotubes

DEFF Research Database (Denmark)

Gaster, Michael

2012-01-01

The diabetic phenotype is complex, requiring elucidation of key initiating defects. Diabetic myotubes express a primary reduced tricarboxylic acid (TCA) cycle flux but at present it is unclear in which part of the TCA cycle the defect is localised. In order to localise the defect we studied ATP p...... production of investigated substrate combinations was significantly reduced in mitochondria isolated from type 2 diabetic subjects compared to lean. However, when ATP synthesis rates at different substrate combinations were normalized to the corresponding individual pyruvate-malate rate...

GAMSOR: Gamma Source Preparation and DIF3D Flux Solution

Energy Technology Data Exchange (ETDEWEB)

Smith, M. A. [Argonne National Lab. (ANL), Argonne, IL (United States); Lee, C. H. [Argonne National Lab. (ANL), Argonne, IL (United States); Hill, R. N. [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-12-15

Nuclear reactors that rely upon the fission reaction have two modes of thermal energy deposition in the reactor system: neutron absorption and gamma absorption. The gamma rays are typically generated by neutron absorption reactions or during the fission process which means the primary driver of energy production is of course the neutron interaction. In conventional reactor physics methods, the gamma heating component is ignored such that the gamma absorption is forced to occur at the gamma emission site. For experimental reactor systems like EBR-II and FFTF, the placement of structural pins and assemblies internal to the core leads to problems with power heating predictions because there is no fission power source internal to the assembly to dictate a spatial distribution of the power. As part of the EBR-II support work in the 1980s, the GAMSOR code was developed to assist analysts in calculating the gamma heating. The GAMSOR code is a modified version of DIF3D and actually functions within a sequence of DIF3D calculations. The gamma flux in a conventional fission reactor system does not perturb the neutron flux and thus the gamma flux calculation can be cast as a fixed source problem given a solution to the steady state neutron flux equation. This leads to a sequence of DIF3D calculations, called the GAMSOR sequence, which involves solving the neutron flux, then the gamma flux, then combining the results to do a summary edit. In this manuscript, we go over the GAMSOR code and detail how it is put together and functions. We also discuss how to setup the GAMSOR sequence and input for each DIF3D calculation in the GAMSOR sequence. With the GAMSOR capability, users can take any valid steady state DIF3D calculation and compute the power distribution due to neutron and gamma heating. The MC2-3 code is the preferable companion code to use for generating neutron and gamma cross section data, but the GAMSOR code can accept cross section data from other sources. To further

Diffusion piecewise homogenization via flux discontinuity ratios

International Nuclear Information System (INIS)

Sanchez, Richard; Dante, Giorgio; Zmijarevic, Igor

2013-01-01

We analyze piecewise homogenization with flux-weighted cross sections and preservation of averaged currents at the boundary of the homogenized domain. Introduction of a set of flux discontinuity ratios (FDR) that preserve reference interface currents leads to preservation of averaged region reaction rates and fluxes. We consider the class of numerical discretizations with one degree of freedom per volume and per surface and prove that when the homogenization and computing meshes are equal there is a unique solution for the FDRs which exactly preserve interface currents. For diffusion sub-meshing we introduce a Jacobian-Free Newton-Krylov method and for all cases considered obtain an 'exact' numerical solution (eight digits for the interface currents). The homogenization is completed by extending the familiar full assembly homogenization via flux discontinuity factors to the sides of regions laying on the boundary of the piecewise homogenized domain. Finally, for the familiar nodal discretization we numerically find that the FDRs obtained with no sub-mesh (nearly at no cost) can be effectively used for whole-core diffusion calculations with sub-mesh. This is not the case, however, for cell-centered finite differences. (authors)

Absolute measurement and international intercomparison of 0.1-0.8 MeV monoenergetic neutron fluence rate

International Nuclear Information System (INIS)

Ma Hongchang; Lu Hanlin; Rong Chaofan

1988-01-01

The methods for absolute measurement of 0.1-18MeV monoenergetic neutron fluence rate are described. Which include proton recoil telescope, semicoducetor telescope, hydrogen filled proportional counter and associated particale method. A long counter used as secondary recent international intercomparison of neutron fluence rate organized by BIPM, and the results were given

Dynamical and biogeochemical control on the decadal variability of ocean carbon fluxes

Directory of Open Access Journals (Sweden)

R. Séférian

2013-04-01

Full Text Available Several recent observation-based studies suggest that ocean anthropogenic carbon uptake has slowed down due to the impact of anthropogenic forced climate change. However, it remains unclear whether detected changes over the recent time period can be attributed to anthropogenic climate change or rather to natural climate variability (internal plus naturally forced variability alone. One large uncertainty arises from the lack of knowledge on ocean carbon flux natural variability at the decadal time scales. To gain more insights into decadal time scales, we have examined the internal variability of ocean carbon fluxes in a 1000 yr long preindustrial simulation performed with the Earth System Model IPSL-CM5A-LR. Our analysis shows that ocean carbon fluxes exhibit low-frequency oscillations that emerge from their year-to-year variability in the North Atlantic, the North Pacific, and the Southern Ocean. In our model, a 20 yr mode of variability in the North Atlantic air-sea carbon flux is driven by sea surface temperature variability and accounts for ~40% of the interannual regional variance. The North Pacific and the Southern Ocean carbon fluxes are also characterised by decadal to multi-decadal modes of variability (10 to 50 yr that account for 20–40% of the interannual regional variance. These modes are driven by the vertical supply of dissolved inorganic carbon through the variability of Ekman-induced upwelling and deep-mixing events. Differences in drivers of regional modes of variability stem from the coupling between ocean dynamics variability and the ocean carbon distribution, which is set by large-scale secular ocean circulation.

The Role of Energy Flux in Weight Management

Directory of Open Access Journals (Sweden)

Clemens Drenowatz

2017-12-01

Full Text Available Excess body weight has been identified as one of the leading threats to public health. In addition to health concerns at the individual level, the increased medical costs put a significant burden on the health care system. Even though an imbalance between energy intake and energy expenditure is ultimately responsible for changes in body weight and body composition such a simple opposition does not reflect the complex interaction of various contributors to energy balance. The limited understanding of the regulation of energy balance is also reflected by rising obesity levels, despite considerable efforts. In addition to energy balance, energy flux, which represents the rate of energy intake and energy expenditure, has been suggested to play an important role in the regulation of energy balance. Particularly a higher energy flux has been associated with a better matching of energy intake and energy expenditure resulting in stable body weight. While a high energy flux has been traditionally attributed to increased levels of physical activity it should be considered that increased body weight also affects energy expenditure and accordingly energy flux. In fact, total daily energy expenditure, and accordingly energy flux, does not differ between people in industrialized countries, living a predominantly sedentary lifestyle and people following a traditional lifestyle, characterized by high physical activity even though there are significant differences in body weight and body composition. It can, therefore, be argued that energy flux, rather than energy balance is a physiologically regulated entity. In this situation body weight and physical activity levels work in opposition to maintain a constant energy flux and weight gain would be a means to maintain a high energy flux with a sedentary lifestyle.

Inverse Flux versus Pressure of Muons from Cosmic Rays

Science.gov (United States)

Buitrago, D.; Armendariz, R.

2017-12-01

When an incoming cosmic ray proton or atom collides with particles in earth's atmosphere a shower of secondary muons is created. Cosmic ray muon flux was measured at the Queensborough Community College using a QuarkNet detector consisting of three stacked scintillator muon counters and a three-fold coincidence trigger. Data was recorded during a three-day period during a severe weather storm that occurred from March 13-17, 2017. A computer program was created in Python to read the muon flux rate and atmospheric pressure sensor readings from the detector's data acquisition board. The program converts the data from hexadecimal to decimal, re-bins the data in a more suitable format, creates and overlays plots of muon flux with atmospheric pressure. Results thus far show a strong correlation between muon flux and atmospheric pressure. More data analysis will be done to verify the above conclusion.

Neutron flux and annealing effects on irradiation hardening of RPV materials

Science.gov (United States)

Chaouadi, R.; Gérard, R.

2011-11-01

This paper aims to examine an eventual effect of neutron flux, sometimes referred to as dose rate effect, on irradiation hardening of a typical A533B reactor pressure vessel steel. Tensile tests on both low flux (reactor surveillance data) and high flux (BR2 reactor) were performed in a large fluence range. The obtained results indicate two features. First, the surveillance data exhibit a constant (˜90 MPa) higher yield strength than the high flux data. However, this difference cannot be explained from a flux effect but most probably from differences in the initial tensile properties. The hardening kinetic of both low and high flux is the same. Annealing at low temperature, 345 °C/40 h, to eventually reveal unstable matrix damage did not affect both BR2 and surveillance specimens. This is confirmed by other annealing experimental data including both tensile and hardness measurements and tensile data on A508 forging and weld. It is suggested that the absence of flux effect on the tensile properties while different radiation-induced microstructures can be attributed to thermal ageing effects.

Design basis for creep of zirconium alloy components in a fast neutron flux

International Nuclear Information System (INIS)

Ross-Ross, P.A.; Fidleris, V.

1975-01-01

The chalk River Nuclear Laboratory's experience with the creep of zirconium alloys in a neutron flux is described. Fast neutron flux changes the creep behaviour of zirconium alloys and new design criteria for in-reactor applications are needed. From experimental results empirical relations describing the effects of neutron flux, stress, temperature, time and anisotropy on creep rate were established. The relations are applied to the design of pressure tubes. (author)

Design basis for creep of zirconium alloy components in a fast neutron flux

International Nuclear Information System (INIS)

Ross-Ross, P.A.; Fidleris, V.

1974-01-01

The Chalk River Nuclear Laboratory's experience with the creep of zirconium alloys in a neutron flux is described. Fast neutron flux changes the creep behavior of zirconium alloys and new design criteria for in-reactor applications are needed. From experimental results empirical relations describing the effects of neutron flux, stress, temperature, time, and anisotropy on creep rate were established. The relations are applied to the design of pressure tubes. (author)

Modelling radiocesium fluxes in forest ecosystems

International Nuclear Information System (INIS)

Shaw, G.; Kliashtorin, A.; Mamikhin, S.; Shcheglov, A.; Rafferty, B.; Dvornik, A.; Zhuchenko, T.; Kuchma, N.

1996-01-01

Monitoring of radiocesium inventories and fluxes has been carried out in forest ecosystems in Ukraine, Belarus and Ireland to determine distributions and rates of migration. This information has been used to construct and calibrate mathematical models which are being used to predict the likely longevity of contamination of forests and forest products such as timber following the Chernobyl accident

OpenFLUX: efficient modelling software for 13C-based metabolic flux analysis

Directory of Open Access Journals (Sweden)

Nielsen Lars K

2009-05-01

Full Text Available Abstract Background The quantitative analysis of metabolic fluxes, i.e., in vivo activities of intracellular enzymes and pathways, provides key information on biological systems in systems biology and metabolic engineering. It is based on a comprehensive approach combining (i tracer cultivation on 13C substrates, (ii 13C labelling analysis by mass spectrometry and (iii mathematical modelling for experimental design, data processing, flux calculation and statistics. Whereas the cultivation and the analytical part is fairly advanced, a lack of appropriate modelling software solutions for all modelling aspects in flux studies is limiting the application of metabolic flux analysis. Results We have developed OpenFLUX as a user friendly, yet flexible software application for small and large scale 13C metabolic flux analysis. The application is based on the new Elementary Metabolite Unit (EMU framework, significantly enhancing computation speed for flux calculation. From simple notation of metabolic reaction networks defined in a spreadsheet, the OpenFLUX parser automatically generates MATLAB-readable metabolite and isotopomer balances, thus strongly facilitating model creation. The model can be used to perform experimental design, parameter estimation and sensitivity analysis either using the built-in gradient-based search or Monte Carlo algorithms or in user-defined algorithms. Exemplified for a microbial flux study with 71 reactions, 8 free flux parameters and mass isotopomer distribution of 10 metabolites, OpenFLUX allowed to automatically compile the EMU-based model from an Excel file containing metabolic reactions and carbon transfer mechanisms, showing it's user-friendliness. It reliably reproduced the published data and optimum flux distributions for the network under study were found quickly ( Conclusion We have developed a fast, accurate application to perform steady-state 13C metabolic flux analysis. OpenFLUX will strongly facilitate and

Calculation of the transmutation rates of Tc-99, I-129 and Cs-135 in the High Flux Reactor, in the Phenix Reactor and in a light water reactor

International Nuclear Information System (INIS)

Bultman, J.

1992-04-01

Transmutation of long-lived fission products is of interest for the reduction of the possible dose to the population resulting from long-term leakage of nuclear waste from waste disposals. Three isotopes are of special interest: Tc-99, I-129 and Cs-135. Therefore, experiments on transmutation of these isotopes in nuclear reactors are planned. In the present study, the possible transmutation rates and mass reductions are determined for experiments in High Flux Reactor (HFR) located in Petten (Netherlands) and in Phenix (France). Also, rates were determined for a standard Light Water Reactor (LWR). The transmutation rates of the 3 fission products will be much higher in HFR than in Phenix reactor, as both total flux and effective cross sections are higher. For thick targets the effective half lives are approximately 3, 2 and 7 years for Tc-99, I-129 and Cs-135 irradiation respectively in HFR and 22, 16 and 40 years for Tc-99, I-129 and Cs-135 irradiation in Phenix reactor. The transmutation rates in LWR are low. Only the relatively large power of LWR guarantees a large total mass reduction. Especially transmutation of Cs-135 will be very difficult in Phenix and LWR, clearly shown by the very long effective half lives of 40 and 100 years, respectively. (author). 7 refs.; 5 figs.; 7 tabs

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.

Neutron flux effect on the fracture toughness behavior of Tihange-III RPV material

International Nuclear Information System (INIS)

Gerard, R.; Chaouadi, R.; Bertolis, D.

2015-01-01

The question whether material test reactor (MTR) data can be used to supplement power reactor pressure vessel (RPV) surveillance data is still debated in the international community and its implications are particularly important in the perspective of long term operation (LTO). However, addressing the flux effect can be confusing if specific material and irradiation variables are not taken into account. This means that the answer to whether there is flux effect or not is neither 'no' nor 'yes' without specifying the application range. Indeed, neutron flux effect was recognized to occur in high Cu-containing steels in the low fluence range. But at high fluence, relevant for long term operation, it becomes difficult to clearly distinguish the differences between high flux and low flux. In this work, we irradiated the low Cu base metal and weld of the Tihange-III surveillance coupon in the BR2 reactor at high flux. The BR2 flux is about two orders of magnitude higher than the flux in the surveillance position. Tensile, Charpy impact and fracture toughness tests were performed on both the surveillance and MTR specimens and compared to assess the neutron flux effect. The results confirm that, at high fluence levels, the flux effect on mechanical properties is not significant, offering therefore the possibility of accelerated irradiation to investigate RPV embrittlement in the high fluence regime relevant for long term operation. (authors)

EFT for vortices with dilaton-dependent localized flux

Energy Technology Data Exchange (ETDEWEB)

Burgess, C.P. [Physics & Astronomy, McMaster University, Hamilton, ON, L8S 4M1 (Canada); Perimeter Institute for Theoretical Physics, Waterloo, ON, N2L 2Y5 (Canada); Division PH -TH, CERN, CH-1211, Genève 23 (Switzerland); Diener, Ross [Physics & Astronomy, McMaster University, Hamilton, ON, L8S 4M1 (Canada); Perimeter Institute for Theoretical Physics, Waterloo, ON, N2L 2Y5 (Canada); Williams, M. [Instituut voor Theoretische Fysica, Katholieke Universiteit Leuven, B-3001 Leuven (Belgium)

2015-11-09

We study how codimension-two objects like vortices back-react gravitationally with their environment in theories (such as 4D or higher-dimensional supergravity) where the bulk is described by a dilaton-Maxwell-Einstein system. We do so both in the full theory, for which the vortex is an explicit classical ‘fat brane’ solution, and in the effective theory of ‘point branes’ appropriate when the vortices are much smaller than the scales of interest for their back-reaction (such as the transverse Kaluza-Klein scale). We extend the standard Nambu-Goto description to include the physics of flux-localization wherein the ambient flux of the external Maxwell field becomes partially localized to the vortex, generalizing the results of a companion paper http://arxiv.org/abs/1506.08095 to include dilaton-dependence for the tension and localized flux. In the effective theory, such flux-localization is described by the next-to-leading effective interaction, and the boundary conditions to which it gives rise are known to play an important role in how (and whether) the vortex causes supersymmetry to break in the bulk. We track how both tension and localized flux determine the curvature of the space-filling dimensions. Our calculations provide the tools required for computing how scale-breaking vortex interactions can stabilize the extra-dimensional size by lifting the dilaton’s flat direction. For small vortices we derive a simple relation between the near-vortex boundary conditions of bulk fields as a function of the tension and localized flux in the vortex action that provides the most efficient means for calculating how physical vortices mutually interact without requiring a complete construction of their internal structure. In passing we show why a common procedure for doing so using a δ-function can lead to incorrect results. Our procedures generalize straightforwardly to general co-dimension objects.

EFT for vortices with dilaton-dependent localized flux

International Nuclear Information System (INIS)

Burgess, C.P.; Diener, Ross; Williams, M.

2015-01-01

We study how codimension-two objects like vortices back-react gravitationally with their environment in theories (such as 4D or higher-dimensional supergravity) where the bulk is described by a dilaton-Maxwell-Einstein system. We do so both in the full theory, for which the vortex is an explicit classical ‘fat brane’ solution, and in the effective theory of ‘point branes’ appropriate when the vortices are much smaller than the scales of interest for their back-reaction (such as the transverse Kaluza-Klein scale). We extend the standard Nambu-Goto description to include the physics of flux-localization wherein the ambient flux of the external Maxwell field becomes partially localized to the vortex, generalizing the results of a companion paper http://arxiv.org/abs/1506.08095 to include dilaton-dependence for the tension and localized flux. In the effective theory, such flux-localization is described by the next-to-leading effective interaction, and the boundary conditions to which it gives rise are known to play an important role in how (and whether) the vortex causes supersymmetry to break in the bulk. We track how both tension and localized flux determine the curvature of the space-filling dimensions. Our calculations provide the tools required for computing how scale-breaking vortex interactions can stabilize the extra-dimensional size by lifting the dilaton’s flat direction. For small vortices we derive a simple relation between the near-vortex boundary conditions of bulk fields as a function of the tension and localized flux in the vortex action that provides the most efficient means for calculating how physical vortices mutually interact without requiring a complete construction of their internal structure. In passing we show why a common procedure for doing so using a δ-function can lead to incorrect results. Our procedures generalize straightforwardly to general co-dimension objects.

Regulation of flux through metabolic cycles

International Nuclear Information System (INIS)

Walsh, K.

1984-01-01

The branchpoint of the tricarboxylic acid and glyoxylate shunt was characterized in the intact organism by a multidimensional approach. Theory and methodology were developed to determine velocities for the net flow of carbon through the major steps of acetate metabolism in E. coli. Rates were assigned based on the 13 C-NMR spectrum of intracellular glutamate, measured rates of substrate incorporation into end products, the constituent composition of E. coli and a series of conservation equations which described the system at steady state. The in vivo fluxes through the branchpoint of the tricarboxylic acid and glyoxylate cycles were compared to rates calculated from the kinetic constants of the branchpoint enzymes and the intracellular concentrations of their substrates. These studies elucidated the role of isocitrate dehydrogenase phosphorylation in the Krebs cycle and led to the development of a generalized mathematical description of the sensitivity of branchpoints to regulatory control. This theoretical analysis was termed the branchpoint effect and it describes conditions which result in large changes in the flux through an enzyme even though that enzyme is not subject to direct regulatory control. The theoretical and experimental characterization of this system provided a framework to study the effects of enzyme overproduction and underproduction on metabolic processes in the cell. An in vivo method was developed to determine the extent to which an enzyme catalyzes a rate-controlling reaction. The enzyme chosen for this study was citrate synthase

Overview of NASA's Carbon Monitoring System Flux-Pilot Project

Science.gov (United States)

Pawson, Steven; Gunson, Michael R.; Jucks, Kenneth

2011-01-01

NASA's space-based observations of physical, chemical and biological parameters in the Earth System along with state-of-the-art modeling capabilities provide unique capabilities for analyses of the carbon cycle. The Carbon Monitoring System is developing an exploratory framework for detecting carbon in the environment and its changes, with a view towards contributing to national and international monitoring activities. The Flux-Pilot Project aims to provide a unified view of land-atmosphere and ocean-atmosphere carbon exchange, using observation-constrained models. Central to the project is the application of NASA's satellite observations (especially MODIS), the ACOS retrievals of the JAXA-GOSAT observations, and the "MERRA" meteorological reanalysis produced with GEOS-S. With a primary objective of estimating uncertainty in computed fluxes, two land- and two ocean-systems are run for 2009-2010 and compared with existing flux estimates. An transport model is used to evaluate simulated CO2 concentrations with in-situ and space-based observations, in order to assess the realism of the fluxes and how uncertainties in fluxes propagate into atmospheric concentrations that can be more readily evaluated. Finally, the atmospheric partial CO2 columns observed from space are inverted to give new estimates of surface fluxes, which are evaluated using the bottom-up estimates and independent datasets. The focus of this presentation will be on the science goals and current achievements of the pilot project, with emphasis on how policy-relevant questions help focus the scientific direction. Examples include the issue of what spatio-temporal resolution of fluxes can be detected from polar-orbiting satellites and whether it is possible to use space-based observations to separate contributions to atmospheric concentrations of (say) fossil-fuel and biological activity

Constraining genome-scale models to represent the bow tie structure of metabolism for 13C metabolic flux analysis

DEFF Research Database (Denmark)

Backman, Tyler W.H.; Ando, David; Singh, Jahnavi

2018-01-01

for a minimum of fluxes into core metabolism to satisfy these experimental constraints. Together, these methods accelerate and automate the identification of a biologically reasonable set of core reactions for use with 13C MFA or 2S- 13C MFA, as well as provide for a substantially lower set of flux bounds......Determination of internal metabolic fluxes is crucial for fundamental and applied biology because they map how carbon and electrons flow through metabolism to enable cell function. 13C Metabolic Flux Analysis (13C MFA) and Two-Scale 13C Metabolic Flux Analysis (2S-13C MFA) are two techniques used...

Evaluation on transmutation performance of minor actinides with high-flux BWR

International Nuclear Information System (INIS)

Setiawan, M.B.; Kitamoto, A.; Taniguchi, A.

2001-01-01

The performance of high-flux BWR (HFBWR) for burning and/or transmutation (B/T) treatment of minor actinides (MA) and long-lived fission products (LLFP) was discussed herein for estimating an advanced waste disposal with partitioning and transmutation (P and T). The concept of high-flux B/T reactor was based on a current 33 GWt-BWR, to transmute the mass of long-lived transuranium (TRU) to short-lived fission products (SLFP). The nuclide selected for B/T treatment was MA (Np-237, Am-241, and Am-243) included in the discharged fuel of LWR. The performance of B/T treatment of MA was evaluated by a new function, i.e. [F/T ratio], defined by the ratio of the fission rate to the transmutation rate in the core, at an arbitrary burn-up, due to all MA nuclides. According to the results, HFBWR could burn and/or transmute MA nuclides with higher fission rate than BWR, but the fission rate did not increase proportionally to the flux increment, due to the higher rate of neutron adsorption. The higher B/T fraction of MA would result in the higher B/T capacity, and will reduce the units of HFBWR needed for the treatment of a constant mass of MA. In addition, HFBWR had a merit of higher mass transmutation compared to the reference BWR, under the same mass loading of MA

New Results from AMS on the International Space Station

CERN Multimedia

CERN. Geneva

2014-01-01

The Alpha Magnetic Spectrometer is a precision particle physics detector. It was installed on the International Space Station on May 19, 2011. Results on electrons and positrons from the first 41 billion events will be presented. This includes the behavior of the positron fraction as a function of energy and the observation that the positron fraction reaches its maximum at energy 275 +/- 32 GeV. The measurement of the positron flux and the electron flux shows that both fluxes change their behavior at 30 GeV but the fluxes are significantly different in their magnitude and energy dependence. The combined (e+ + e-) flux will also be presented.

Development and validation status of the IFMIF High Flux Test Module

International Nuclear Information System (INIS)

Arbeiter, Frederik; Abou-Sena, Ali; Chen Yuming; Dolensky, Bernhard; Heupel, Tobias; Klein, Christine; Scheel, Nicola; Schlindwein, Georg

2011-01-01

The development of the IFMIF (International Fusion Material Irradiation Facility) High Flux Test Module in the EVEDA (Engineering Validation and Engineering Design Activities) phase up to 2013 includes conceptual design, engineering analyses, as well as design and engineering validation by building of prototypes and their testing. The High Flux Test Module is the device to facilitate the irradiation of SSTT samples of RAFM steels at temperatures 250-550 deg. C and up to an accumulated irradiation damage of 150 dpa. The requirements, the current design and the performance of the module are discussed, and the development process is outlined.

Development and validation status of the IFMIF High Flux Test Module

Energy Technology Data Exchange (ETDEWEB)

Arbeiter, Frederik, E-mail: frederik.arbeiter@kit.edu [Karlsruhe Institute of Technology, Institute for Neutron Physics and Reactor Technology (KIT-INR), Karlsruhe (Germany); Abou-Sena, Ali; Chen Yuming; Dolensky, Bernhard; Heupel, Tobias; Klein, Christine; Scheel, Nicola; Schlindwein, Georg [Karlsruhe Institute of Technology, Institute for Neutron Physics and Reactor Technology (KIT-INR), Karlsruhe (Germany)

2011-10-15

The development of the IFMIF (International Fusion Material Irradiation Facility) High Flux Test Module in the EVEDA (Engineering Validation and Engineering Design Activities) phase up to 2013 includes conceptual design, engineering analyses, as well as design and engineering validation by building of prototypes and their testing. The High Flux Test Module is the device to facilitate the irradiation of SSTT samples of RAFM steels at temperatures 250-550 deg. C and up to an accumulated irradiation damage of 150 dpa. The requirements, the current design and the performance of the module are discussed, and the development process is outlined.

GEM-CEDAR Challenge: Poynting Flux at DMSP and Modeled Joule Heat

Science.gov (United States)

Rastaetter, Lutz; Shim, Ja Soon; Kuznetsova, Maria M.; Kilcommons, Liam M.; Knipp, Delores J.; Codrescu, Mihail; Fuller-Rowell, Tim; Emery, Barbara; Weimer, Daniel R.; Cosgrove, Russell;

Experimental Study on Hot Metal Desulfurization Using Sintered Red Mud-Based Flux

Science.gov (United States)

Li, Fengshan; Zhang, Yanling; Guo, Zhancheng

2017-09-01

This research presents the results of laboratory and pilot-scale tests conducted on the use of sintered red mud (RM)-based flux in the hot metal desulfurization (HMD) process. Al2O3/Na2O in RM can decrease the melting point of lime-based slag and can work as a flux in the HMD process. Good slag fluidity was observed throughout the process, and high desulfurization rates ( 80%) with a low final S content (pilot-scale test results indicated that a desulfurization rate as high as 91% and a S content <0.0099% could be acquired when RM:lime = 1:1, verifying the feasibility of using sintered RM-based flux in HMD. The data obtained provide important information for promoting the large-scale application of sintered RM in steelmaking.

A simple model of the distant Jovian tail with magnetic flux loss

International Nuclear Information System (INIS)

Grzedzielski, S.; Macek, W.; Oberc, P.

1982-01-01

The influence of a small rate of magnetic flux loss on a simple hydromagnetic model of the distant Jovian tail was estimated. The loss of flux leads to a 10-15% decrease of the tail radius at Saturn's distance. Possible encounter of the tail with Uranus in 1983 is also briefly discussed. (author)

Cosmic muon flux measurements at the Kimballton Underground Research Facility

International Nuclear Information System (INIS)

Kalousis, L N; Guarnaccia, E; Link, J M; Mariani, C; Pelkey, R

2014-01-01

In this article, the results from a series of muon flux measurements conducted at the Kimballton Underground Research Facility (KURF), Virginia, United States, are presented. The detector employed for these investigations, is made of plastic scintillator bars readout by wavelength shifting fibers and multianode photomultiplier tubes. Data was taken at several locations inside KURF, spanning rock overburden values from ∼ 200 to 1450 m.w.e. From the extracted muon rates an empirical formula was devised, that estimates the muon flux inside the mine as a function of the overburden. The results are in good agreement with muon flux calculations based on analytical models and MUSIC

Determination of the atmospheric neutrino fluxes from atmospheric neutrino data

International Nuclear Information System (INIS)

Gonzalez-Garcia, C.; Maltoni, M.; Rojo, J.

2006-06-01

The precise knowledge of the atmospheric neutrino fluxes is a key ingredient in the interpretation of the results from any atmospheric neutrino experiment. In the standard data analysis, these fluxes are theoretical inputs obtained from sophisticated numerical calculations based on the convolution of the primary cosmic ray spectrum with the expected yield of neutrinos per incident cosmic ray. In this work we present an alternative approach to the determination of the atmospheric neutrino fluxes based on the direct extraction from the experimental data on neutrino event rates. The extraction is achieved by means of a combination of artificial neural networks as interpolants and Monte Carlo methods for faithful error estimation. (author)

Determination of the atmospheric neutrino fluxes from atmospheric neutrino data

International Nuclear Information System (INIS)

Gonzalez-Garcia, Concepcion; Maltoni, Michele; Rojo, Joan

2006-01-01

The precise knowledge of the atmospheric neutrino fluxes is a key ingredient in the interpretation of the results from any atmospheric neutrino experiment. In the standard data analysis, these fluxes are theoretical inputs obtained from sophisticated numerical calculations based on the convolution of the primary cosmic ray spectrum with the expected yield of neutrinos per incident cosmic ray. In this work we present an alternative approach to the determination of the atmospheric neutrino fluxes based on the direct extraction from the experimental data on neutrino event rates. The extraction is achieved by means of a combination of artificial neural networks as interpolants and Monte Carlo methods for faithful error estimation

Deuterium-induced nanostructure formation on tungsten exposed to high-flux plasma

NARCIS (Netherlands)

Xu, H.Y.; De Temmerman, G.C.; Luo, G.-N.; Jia, Y.Z.; Yuan, Y.; Fu, B.Q.; Godfrey, A.; Liu, W.

2015-01-01

PLASMA-SURFACE INTERACTIONS 21 — Proceedings of the 21st International Conference on Plasma-Surface Interactions in Controlled Fusion Devices Kanazawa, Japan May 26-30, 2014 Surface topography of polycrystalline tungsten (W) have been examined after exposure to a low-energy (38 eV/D), high-flux

Magnetic flux creep in HTSC and Anderson-Kim theory

International Nuclear Information System (INIS)

Lykov, A.N.

2014-01-01

The theoretical and experimental data on flux creep in high-temperature superconductors (HTSC) were analyzed in the review paper. On the one hand, the main attention is paid to the most striking experimental results which have had a significant influence on the investigations of flux creep in HTSC. On the other hand, the analysis of theoretical studies is concentrated on the works, which explain the features of flux creep on the basis of the Anderson-Kim (AK) theory modifications, and received previously unsufficient attention. However, it turned out that the modified AK theory could explain a lot of features of flux creep in HTSC: the scaling behaviour of current-voltage curves of HTSC, the finite rate of flux creep at ultra low temperatures, the logarithmic dependence of effective pinning potential as a function of transport current and its decrease with temperature. The harmonic potential field which is used in this approach makes it possible to solve accurately the both problems: viscous vortex motion and flux creep in this field. Moreover the distribution of pinning potential and the interaction of vortices with each other are taken into account in the approach. Thus, the modification of the AK theory consists, essentially, in its detailed elaboration and approaching to real situations in superconductors

Burnout heat flux in natural flow boiling

International Nuclear Information System (INIS)

Helal, M.M.; Darwish, M.A.; Mahmoud, S.I.

1978-01-01

Twenty runs of experiments were conducted to determine the critical heat flux for natural flow boiling with water flowing upwards through annuli of centrally heated stainless steel tube. The test section has concentric heated tube of 14mm diameter and heated lengthes of 15 and 25 cm. The outside surface of the annulus was formed by various glass tubes of 17.25, 20 and 25.9mm diameter. System pressure is atmospheric. Inlet subcooling varied from 18 to 5 0 C. Obtained critical heat flux varied from 24.46 to 62.9 watts/cm 2 . A number of parameters having dominant influence on the critical heat flux and hydrodynamic instability (flow and pressure oscillations) preceeding the burnout have been studied. These parameters are mass flow rate, mass velocity, throttling, channel geometry (diameters ratio, length to diameter ratio, and test section length), and inlet subcooling. Flow regimes before and at the moments of burnout were observed, discussed, and compared with the existing physical model of burnout

On the increase and decay of the electron fluxes at GEO

Science.gov (United States)

Boynton, R.; Balikhin, M. A.; Alipudin, R.; Chiu, C.; Aryan, H.

2013-12-01

The population of electrons in the Earth's outer radiation belt increases when the magnetosphere is exposed to high speed streams of solar wind. After this increase, the number of electrons decays back to approximately the initial population. This study statistically analyses the increase and decay of the electron fluxes at GEO. For the increase in electrons, the IMF and velocity of the corotating interaction regions is compared to the rate and magnitude of the increase, to determine how the IMF influences the electron population at GEO. The decay rate of the electron fluxes are calculated for 14 energies ranging from 24 keV to 3.5 MeV to identify a relationship between the decay rate and energy of the electrons.

The Effect of the Heat Flux on the Self-Ignition of Oriented Strand Board

Science.gov (United States)

Hirle, Siegfried; Balog, Karol

2017-06-01

This article deals with the initiation phase of flaming and smouldering burning of oriented strand board. The influence of heat flux on thermal degradation of OSB boards, time to ignition, heat release rate and mass loss rate using thermal analysis and vertical electrical radiation panel methods were studied. Significant information on the influence of the heat flux density and the thickness of the material on time to ignition was obtained.

IAEA coordinated research project (CRP). The use of selected safety indicators (concentrations, fluxes) in the assessment of radioactive waste disposal. Report 5: Chemical weathering rates on the Baltic Shield of Finland for use as indicators of nuclear waste repository safety

International Nuclear Information System (INIS)

Tarvainen, T.; Backman, B.; Hatakka, T.; Savolainen, H.; Hellmuth, K.-H.

2003-01-01

In this report the available information from the literature on chemical erosion and weathering rates in Finland and northern Sweden is reviewed and experimental data from recent followup studies in defined catchments is discussed. In glaciated terrain as in Finland the best estimates of chemical erosion rates are obtained when geochemical data of glacial till is used. Elemental fluxes in free-flowing rivers and river-lake systems have been studied in greater detail only in a few case studies. The Kalix river drainage basin investigations gave evidence that the mobilization of rare earth elements (REE) is determined by weathering processes in the upper till layers and that the C-horizon below about 0.75 m depth or generally below the groundwater table is practically unaffected by weathering. Also the removal of U from the watershed was found to happen mostly by groundwater flow through predominantly shallow aquifers. Another type of case study is constrained to regions where certain phenomena cause enhanced trace metal mobilization, as in a region stretched along the western coast of Finland where land-uplift exposes clay sediments rich in sulphides above the groundwater level, with the consequence of increased mobilization of a number of heavy metals. Very little quantitative information on elemental flux balances is available from river-lake systems. Some modelling has been attempted on one great lake system the lake Paeijaenne by use of fall-out nuclides. From the same lake a detailed record of sedimentation rates covering the whole period from the end of the latest glaciation to present is available and erosion rate variations since the end of the latest glaciation can be assessed. The main part of this study focusses on investigations of well-defined small catchments over a longer time period, where groundwater is discharging in springs. Geochemical fluxes worth mentioning seem to be constrained to the surficial geological layers which include overburden and

Comparison of WindTrax and flux-gradient technique in determining PM10 emission rates from a beef cattle feedlot

Science.gov (United States)

Several emission estimation methods can be used to determine emission fluxes from ground-level area sources, including open-lot beef cattle feedlots. This research determined PM10 emission fluxes from a commercial cattle feedlot in Kansas using WindTrax, a backward Lagrangian stochastic-based atmosp...

Active control of divertor heat and particle fluxes in EAST towards advanced steady state operations

Energy Technology Data Exchange (ETDEWEB)

Wang, L., E-mail: lwang@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Dalian University of Technology, Dalian 116024 (China); Guo, H.Y. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); General Atomics, P. O. Box 85608, San Diego, CA 92186 (United States); Li, J.; Wan, B.N.; Gong, X.Z.; Zhang, X.D.; Hu, J.S. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Liang, Y. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Association EURATOM-FZJ, D-52425 Jülich (Germany); Xu, G.S. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zou, X.L. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Loarte, A. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Maingi, R.; Menard, J.E. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Luo, G.N.; Gao, X.; Hu, L.Q.; Gan, K.F.; Liu, S.C.; Wang, H.Q.; Chen, R. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); and others

2015-08-15

Significant progress has been made in EAST towards advanced steady state operations by active control of divertor heat and particle fluxes. Many innovative techniques have been developed to mitigate transient ELM and stationary heat fluxes on the divertor target plates. It has been found that lower hybrid current drive (LHCD) can lead to edge plasma ergodization, striation of the stationary heat flux and lower ELM transient heat and particle fluxes. With multi-pulse supersonic molecular beam injection (SMBI) to quantitatively regulate the divertor particle flux, the divertor power footprint pattern can be actively modified. H-modes have been extended over 30 s in EAST with the divertor peak heat flux and the target temperature being controlled well below 2 MW/m{sup 2} and 250 °C, respectively, by integrating these new methods, coupled with advanced lithium wall conditioning and internal divertor pumping, along with an edge coherent mode to provide continuous particle and power exhaust.

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)

Flux and fluence determination using the material scrapings approach

International Nuclear Information System (INIS)

Basha, H.S.; Manahan, M.P.

1992-01-01

The conventional approach to flux determination is to use high-purity dosimeters to characterize the neutron field. This paper presents an alternative approach called the scraping method. This method consists of taking scraping samples from an in-service component and using this material to measure the specific activity for various reactions. This approach enables the determination of the neutron flux and fluence incident on any component for which small chips of material can be safely obtained. It offers a capability for determining the neutron flux for components such as reactor internals without destructively removing them from service. The scrapings methodology was benchmarked by comparison with the results obtained using conventional dosimetry data from the San Onofre nuclear generation station Unit 2 (SONGS-2). Additionally, since the goal of any reactor physics analysis is to reduce uncertainty to the extent practical, it is important that the best available cross-section library be used. The fast flux calculated-to-experimental (C/E) ratios at the SONGS-297-deg in-vessel surveillance capsule and the REACTOR-X 90-deg ex-vessel dosimetry positions were studied for several cross-section libraries, including BIGLE-80, SAILOR, and ELXSIR. REACTOR-X is a pressurized water reactor power plant currently operating in the US

Flux consumption optimization and the achievement of 1 MA discharges on NSTX

International Nuclear Information System (INIS)

Menard, J.; LeBlanc, B.; Sabbagh, S.A.

2001-01-01

The spherical tokamak (ST), because of its slender central column, has very limited volt-second capability relative to a standard aspect ratio tokamak of similar plasma cross-section. Recent experiments on the National Spherical Torus Experiment (NSTX) have begun to quantify and optimize the ohmic current drive efficiency in a MA-class ST device. Sustainable ramp-rates in excess of 5MA/sec during the current rise phase have been achieved on NSTX, while faster ramps generate significant MHD activity. Discharges with I P exceeding 1MA have been achieved in NSTX with nominal parameters: aspect ratio A=1.3-1.4, elongation κ=2-2.2, triangularity δ=0.4, internal inductance l i =0.6, and Ejima coefficient C E =0.35. Flux consumption efficiency results, performance improvements associated with first boronization, and comparisons to neoclassical resistivity are described. (author)

Dryout heat flux in a debris bed with forced coolant flow from below

International Nuclear Information System (INIS)

Bang, Kwang-Hyun; Kim, Jong-Myung

2004-01-01

The objective of the present study is to experimentally investigate the enhancement of dryout heat flux in debris beds with coolant flow from below. The experimental facility consists mainly of an induction heater (40 kW, 35 kHz), a double-wall quartz-tube test section containing steel-particle bed and coolant injection and recovery condensing loop. A fairly uniform heating of particle bed was achieved by induction heating. This paper reports the experimental data for 5 mm particle bed and 300 mm bed height. The dryout heat rate data were obtained of both top-flooding case and forced coolant injection from below with the injection mass flux up to 1.5 kg/m 2 s. For the top-flooded case, the volumetric dryout heat rate was about 4 MW/m 3 and it increased as the rate of coolant injection from below was increased. At the coolant injection mass flux of 1.5 kg/m 2 s, the volumetric dryout heat rate was about 10 MW/m 3 , the enhancement factor was more than two. (author)

A process-based {sup 222}radon flux map for Europe and its comparison to long-term observations

Energy Technology Data Exchange (ETDEWEB)

Karstens, U. [Max-Planck-Instistut fuer Biogeochemie, Jena (Germany); Schwingshackl, C.; Schmithuesen, D.; Levin, I. [Heidelberg Univ. (Germany). Inst. fuer Umweltphysik

2015-07-01

Detailed {sup 222}radon ({sup 222}Rn) flux maps are an essential pre-requisite for the use of radon in atmospheric transport studies. Here we present a high-resolution {sup 222}Rn flux map for Europe, based on a parameterization of {sup 222}Rn production and transport in the soil. The {sup 222}Rn exhalation rate is parameterized based on soil properties, uranium content, and modelled soil moisture from two different land-surface reanalysis data sets. Spatial variations in exhalation rates are primarily determined by the uranium content of the soil, but also influenced by soil texture and local water-table depth. Temporal variations are related to soil moisture variations as the molecular diffusion in the unsaturated soil zone depends on available air-filled pore space. The implemented diffusion parameterization was tested against campaign-based {sup 222}Rn soil profile measurements. Monthly {sup 222}Rn exhalation rates from European soils were calculated with a nominal spatial resolution of 0.083 x 0.083 and compared to long-term direct measurements of {sup 222}Rn exhalation rates in different areas of Europe. The two realizations of the {sup 222}Rn flux map, based on the different soil moisture data sets, both realistically reproduce the observed seasonality in the fluxes but yield considerable differences for absolute flux values. The mean {sup 222}Rn flux from soils in Europe is estimated to be 10 mBq m{sup -2} s{sup -1} (ERA-Interim/Land soil moisture) or 15 mBq m{sup -2} s{sup -1} (GLDAS (Global Land Data Assimilation System) Noah soil moisture) for the period 2006-2010. The corresponding seasonal variations with low fluxes in winter and high fluxes in summer range in the two realizations from ca. 7 to ca. 14 mBq m{sup -2} s{sup -1} and from ca. 11 to ca. 20 mBq m{sup -2} s{sup -1}, respectively. These systematic differences highlight the importance of realistic soil moisture data for a reliable estimation of {sup 222}Rn exhalation rates. Comparison with

Thermodynamic consistency of viscoplastic material models involving external variable rates in the evolution equations for the internal variables

International Nuclear Information System (INIS)

Malmberg, T.

1993-09-01

The objective of this study is to derive and investigate thermodynamic restrictions for a particular class of internal variable models. Their evolution equations consist of two contributions: the usual irreversible part, depending only on the present state, and a reversible but path dependent part, linear in the rates of the external variables (evolution equations of ''mixed type''). In the first instance the thermodynamic analysis is based on the classical Clausius-Duhem entropy inequality and the Coleman-Noll argument. The analysis is restricted to infinitesimal strains and rotations. The results are specialized and transferred to a general class of elastic-viscoplastic material models. Subsequently, they are applied to several viscoplastic models of ''mixed type'', proposed or discussed in the literature (Robinson et al., Krempl et al., Freed et al.), and it is shown that some of these models are thermodynamically inconsistent. The study is closed with the evaluation of the extended Clausius-Duhem entropy inequality (concept of Mueller) where the entropy flux is governed by an assumed constitutive equation in its own right; also the constraining balance equations are explicitly accounted for by the method of Lagrange multipliers (Liu's approach). This analysis is done for a viscoplastic material model with evolution equations of the ''mixed type''. It is shown that this approach is much more involved than the evaluation of the classical Clausius-Duhem entropy inequality with the Coleman-Noll argument. (orig.) [de

Evaluation of upward heat flux in ex-vessel molten core heat transfer using MELCOR

International Nuclear Information System (INIS)

Park, S.Y.; Park, J.H.; Kim, S.D.; Kim, D.H.; Kim, H.D.

2000-01-01

The purpose of this study is to share experiences of MELCOR application to resolve the molten corium-concrete interaction (MCCI) issue in the Korea Next Generation Reactor (KNGR). In the evaluation of concrete erosion, the heat transfer modeling from the molten corium internal to the corium pool surface is very important and uncertain. MELCOR employs Kutateladze or Greene's bubble-enhanced heat transfer model for the internal heat transfer. The phenomenological uncertainty is so large that the model provides several model parameters in addition to the phenomenological model for user flexibility. However, the model parameters do not work on Kutateladze correlation at the top of the molten layer. From our experience, a code modification is suggested to match the upward heat flux with the experimental results. In this analysis, minor modification was carried out to calculate heat flux from the top molten layer to corium surface, and efforts were made to find out the best value of the model parameter based on upward heat flux of MACE test M1B. Discussion also includes its application to KNGR. (author)

Money market rates and implied CCAPM rates: some international evidence

OpenAIRE

Yamin Ahmad

2004-01-01

New Neoclassical Synthesis models equate the instrument of monetary policy to the implied CCAPM rate arising from an Euler equation. This paper identifies monetary policy shocks within six of the G7 countries and examines the movement of money market and implied CCAPM rates. The key result is that an increase in the nominal interest rate leads to a fall in the implied CCAPM rate. Incorporating habit still yields the same result. The findings suggest that the movement of these two rates implie...

Mathematical models in Slowpoke reactor internal irradiation site

International Nuclear Information System (INIS)

Raza, J.

2007-01-01

The main objective is to build representative mathematical models of neutron activation analysis in a Slowpoke internal irradiation site. Another significant objective is to correct various elements neutron activation analysis measured mass using these models. The neutron flux perturbation is responsible for the measured under-estimation of real masses. We supposed that neutron flux perturbation measurements taken during the Ecole Polytechnique de Montreal Slowpoke reactor first fuel loading were still valid after the second fuelling. .We also supposed that the thermal neutrons spatial and kinetic energies distributions as well as the absorption microscopic cross section dependence on the neutrons kinetic energies were important factors to satisfactorily represent neutron activation analysis results. In addition, we assumed that the neutron flux is isotropic in the laboratory system. We used experimental results from the Slowpoke reactor internal irradiation sites, in order to validate our mathematical models. Our models results are in close agreement with these experimental results..We established an accurate global mathematical correlation of the neutron flux perturbation in function of samples volumes and macroscopic neutron absorption cross sections. It is applicable to sample volumes ranging from 0,1 to 1,3 ml and macroscopic neutron absorption cross section up to 5 moles-b for seven (7) elements with atomic numbers (Z) ranging from 5 to 79. We first came up with a heuristic neutron transport mathematical semi-analytical model, in order to better understand neutrons behaviour in presence of one of several different nuclei samples volumes and mass. In order to well represent the neutron flux perturbation, we combined a neutron transport solution obtained from the spherical harmonics method of a finite cylinder and a mathematical expression combining two cylindrical harmonic functions..With the help of this model and the least squares method, we made extensive

Convective boundary layer flow and heat transfer in a nanofluid in the presence of second order slip, constant heat flux and zero nanoparticles flux

Energy Technology Data Exchange (ETDEWEB)

Rahman, M.M., E-mail: mansurdu@yahoo.com [Department of Mathematics and Statistics, College of Science, Sultan Qaboos University, PO Box 36, PC 123 Al-Khod, Muscat (Oman); Al-Rashdi, Maryam H. [Department of Mathematics and Statistics, College of Science, Sultan Qaboos University, PO Box 36, PC 123 Al-Khod, Muscat (Oman); Pop, I. [Department of Mathematics, Faculty of Mathematics and Computer Science, Babeş-Bolyai University, Cluj-Napoca 400084 (Romania)

2016-02-15

Highlights: • Convective boundary layer flow and heat transfer in a nanofluid is investigated. • Second order slip increases the rate of shear stress and decreases the rate of heat transfer in a nanofluid. • In nanofluid flow zero normal flux of the nanoparticles at the surface is realistic to apply. • Multiple solutions are identified for certain values of the parameter space. • The upper branch solution is found to be stable, hence physically realizable. - Abstract: In this work, the effects of the second order slip, constant heat flux, and zero normal flux of the nanoparticles due to thermophoresis on the convective boundary layer flow and heat transfer characteristics in a nanofluid using Buongiorno's model over a permeable shrinking sheet is studied theoretically. The nonlinear coupled similarity equations are solved using the function bvp4c using Matlab. Similarity solutions of the flow, heat transfer and nanoparticles volume fraction are presented graphically for several values of the model parameters. The results show that the application of second order slip at the interface is found to be increased the rate of shear stress and decreased the rate of heat transfer in a nanofluid, so need to be taken into account in nanofluid modeling. The results further indicate that multiple solutions exist for certain values of the parameter space. The stability analysis provides guarantee that the lower branch solution is unstable, while the upper branch solution is stable and physically realizable.

Localizing by autoradiography at -195 deg radioactive areas in rats exposed to a high flux of thermal neutrons, importance of phosphorus 32 in consecutive internal irradiation; Localisation par autoradiographie a -195 deg des zones radioactives chez le rat expose a un haut flux de neutrons thermiques, importance du phosphore 32 dans l'irradiation interne consecutive

Energy Technology Data Exchange (ETDEWEB)

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

1961-07-01

Rats weighing 25 g were exposed for 5 mn to a flux of 6.10{sup 12} thermal neutrons/cm{sup 2}/s. Anatomical autoradiography at -195 deg. C has enabled the radioactive organs to be easily localised, to follow in course of time the decrease of radioactivity, and from it to deduce the probable nature of the numerous emitters in question. In particular, the phosphorus 32 has thus appeared to be one of those responsible for internal irradiation, general, on the one hand, by activating cellular phosphorus, local, on the other, by activating bony phosphates. Owing to this, an accidental irradiation by neutrons might have consequences that are both somatic (elective irradiation of the bone marrow) and genetic (activation of nucleic acids). The gamma spectrometry has confirmed the nature of certain other emitters. (author) [French] Des rats de 25 g ont ete exposes pendant 5 mn a un flux de 6.10{sup 12} neutrons thermiques/cm{sup 2}/s. L'autoradiographie anatomique a -195 deg. C a permis de localiser facilement les organes radioactifs, de suivre dans le temps la decroissance de la radioactivite, et d'en deduire la nature probable des nombreux emetteurs en cause. En particulier, le phosphore 32 est ainsi apparu comme l'un des responsables de l'irradiation interne, d'une part generale par activation du phosphore cellulaire, d'autre part locale par activation des phosphates osseux. Une irradiations accidentelle par neutrons aurait, de ce fait, des consequences a la fois somatiques (irradiation elective de la moelle osseuse) et genetiques (activation des acides nucleiques). La spectrometrie gamma a confirme la nature de certains autres emetteurs. (auteur)

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.

Estimation of Surface Temperature and Heat Flux by Inverse Heat Transfer Methods Using Internal Temperatures Measured While Radiantly Heating a Carbon/Carbon Specimen up to 1920 F

Science.gov (United States)

Pizzo, Michelle; Daryabeigi, Kamran; Glass, David

2015-01-01

The ability to solve the heat conduction equation is needed when designing materials to be used on vehicles exposed to extremely high temperatures; e.g. vehicles used for atmospheric entry or hypersonic flight. When using test and flight data, computational methods such as finite difference schemes may be used to solve for both the direct heat conduction problem, i.e., solving between internal temperature measurements, and the inverse heat conduction problem, i.e., using the direct solution to march forward in space to the surface of the material to estimate both surface temperature and heat flux. The completed research first discusses the methods used in developing a computational code to solve both the direct and inverse heat transfer problems using one dimensional, centered, implicit finite volume schemes and one dimensional, centered, explicit space marching techniques. The developed code assumed the boundary conditions to be specified time varying temperatures and also considered temperature dependent thermal properties. The completed research then discusses the results of analyzing temperature data measured while radiantly heating a carbon/carbon specimen up to 1920 F. The temperature was measured using thermocouple (TC) plugs (small carbon/carbon material specimens) with four embedded TC plugs inserted into the larger carbon/carbon specimen. The purpose of analyzing the test data was to estimate the surface heat flux and temperature values from the internal temperature measurements using direct and inverse heat transfer methods, thus aiding in the thermal and structural design and analysis of high temperature vehicles.

Magnetospheric Multiscale Mission Observations of Magnetic Flux Ropes in the Earth's Plasma Sheet

Science.gov (United States)

Slavin, J. A.; Akhavan-Tafti, M.; Poh, G.; Le, G.; Russell, C. T.; Nakamura, R.; Baumjohann, W.; Torbert, R. B.; Gershman, D. J.; Pollock, C. J.; Giles, B. L.; Moore, T. E.; Burch, J. L.

2017-12-01

A major discovery by the Cluster mission and the previous generation of science missions is the presence of earthward and tailward moving magnetic flux ropes in the Earth's plasma sheet. However, the lack of high-time resolution plasma measurements severely limited progress concerning the formation and evolution of these reconnection generated structures. We use high-time resolution magnetic and electric field and plasma measurements from the Magnetospheric Multiscale mission's first tail season to investigate: 1) the distribution of flux rope diameters relative to the local ion and electron inertial lengths; 2) the internal force balance sustaining these structures; and 3) the magnetic connectivity of the flux ropes to the Earth and/or the interplanetary medium; 4) the specific entropy of earthward moving flux ropes and the possible effect of "buoyancy" on how deep they penetrate into the inner magnetosphere; and 5) evidence for coalescence of adjacent flux ropes and/or the division of existing flux ropes through the formation of secondary X-lines. The results of these initial analyses will be discussed in terms of their implications for reconnection-driven magnetospheric dynamics and substorms.

The glycolytic flux in Escherichia coli is controlled by the demand for ATP

DEFF Research Database (Denmark)

Købmann, Brian Jensen; Westerhoff, H.V.; Snoep, J.L.

2002-01-01

additional ATP hydrolysis, we increased the flux through glycolysis to 1.7 times that of the wild-type flux. The results demonstrate why attempts in the past to increase the glycolytic flux through overexpression of glycolytic enzymes have been unsuccessful: the majority of flux control (> 75%) resides...... not inside but outside the pathway, i.e., with the enzymes that hydrolyze ATP. These data further allowed us to answer the question of whether catabolic or anabolic reactions control the growth of E. coli. We show that the majority of the control of growth rate resides in the anabolic reactions, i...

Pre-eruptive Magnetic Reconnection within a Multi-flux-rope System in the Solar Corona

Science.gov (United States)

Awasthi, Arun Kumar; Liu, Rui; Wang, Haimin; Wang, Yuming; Shen, Chenglong

2018-04-01

The solar corona is frequently disrupted by coronal mass ejections (CMEs), whose core structure is believed to be a flux rope made of helical magnetic field. This has become a “standard” picture; though, it remains elusive how the flux rope forms and evolves toward eruption. While one-third of the ejecta passing through spacecraft demonstrate a flux-rope structure, the rest have complex magnetic fields. Are they originating from a coherent flux rope, too? Here we investigate the source region of a complex ejecta, focusing on a flare precursor with definitive signatures of magnetic reconnection, i.e., nonthermal electrons, flaring plasma, and bidirectional outflowing blobs. Aided by nonlinear force-free field modeling, we conclude that the reconnection occurs within a system of multiple braided flux ropes with different degrees of coherency. The observation signifies the importance of internal structure and dynamics in understanding CMEs and in predicting their impacts on Earth.

Aerosol fluxes and particle growth above managed grassland

Directory of Open Access Journals (Sweden)

E. Nemitz

2009-08-01

Full Text Available Particle deposition velocities (11–3000 nm diameter measured above grassland by eddy covariance during the EU GRAMINAE experiment in June 2000 averaged 0.24 and 0.03 mm s⁻¹ to long (0.75 m and short (0.07 m grass, respectively. After fertilisation with 108 kg N ha⁻¹ as calcium ammonium nitrate, sustained apparent upward fluxes of particles were observed. Analysis of concentrations and fluxes of potential precursor gases, including NH₃, HNO₃, HCl and selected VOCs, shows that condensation of HNO₃ and NH₃ on the surface of existing particles is responsible for this effect. A novel approach is developed to derive particle growth rates at the field scale, from a combination of measurements of vertical fluxes and particle size-distributions. For the first 9 days after fertilization, growth rates of 11 nm particles of 7.04 nm hr⁻¹ and 1.68 nm hr⁻¹ were derived for day and night-time conditions, respectively. This implies total NH₄NO₃ production rates of 1.11 and 0.44 μg m⁻³ h⁻¹, respectively. The effect translates into a small error in measured ammonia fluxes (0.06% day, 0.56% night and a large error in NH₄⁺ and NO₃⁻ aerosol fluxes of 3.6% and 10%, respectively. By converting rapidly exchanged NH₃ and HNO₃ into slowly depositing NH₄NO₃, the reaction modifies the total N budget, though this effect is small (<1% for the 10 days following fertilization, as NH₃ emission dominates the net flux. It is estimated that 3.8% of the fertilizer N was volatilised as NH₃, of which 0.05% re-condensed to form NH₄NO₃ particles within the lowest 2 m of the surface layer. This surface induced process would at least scale up to a global NH₄NO₃ formation of ca. 0.21 kt N yr

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

The Effect of the Heat Flux on the Self-Ignition of Oriented Strand Board

Directory of Open Access Journals (Sweden)

Hirle Siegfried

2017-06-01

Full Text Available This article deals with the initiation phase of flaming and smouldering burning of oriented strand board. The influence of heat flux on thermal degradation of OSB boards, time to ignition, heat release rate and mass loss rate using thermal analysis and vertical electrical radiation panel methods were studied. Significant information on the influence of the heat flux density and the thickness of the material on time to ignition was obtained.

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

International Nuclear Information System (INIS)

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

1998-01-01

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

The Protein Cost of Metabolic Fluxes: Prediction from Enzymatic Rate Laws and Cost Minimization.

Directory of Open Access Journals (Sweden)

Elad Noor

2016-11-01

Full Text Available Bacterial growth depends crucially on metabolic fluxes, which are limited by the cell's capacity to maintain metabolic enzymes. The necessary enzyme amount per unit flux is a major determinant of metabolic strategies both in evolution and bioengineering. It depends on enzyme parameters (such as kcat and KM constants, but also on metabolite concentrations. Moreover, similar amounts of different enzymes might incur different costs for the cell, depending on enzyme-specific properties such as protein size and half-life. Here, we developed enzyme cost minimization (ECM, a scalable method for computing enzyme amounts that support a given metabolic flux at a minimal protein cost. The complex interplay of enzyme and metabolite concentrations, e.g. through thermodynamic driving forces and enzyme saturation, would make it hard to solve this optimization problem directly. By treating enzyme cost as a function of metabolite levels, we formulated ECM as a numerically tractable, convex optimization problem. Its tiered approach allows for building models at different levels of detail, depending on the amount of available data. Validating our method with measured metabolite and protein levels in E. coli central metabolism, we found typical prediction fold errors of 4.1 and 2.6, respectively, for the two kinds of data. This result from the cost-optimized metabolic state is significantly better than randomly sampled metabolite profiles, supporting the hypothesis that enzyme cost is important for the fitness of E. coli. ECM can be used to predict enzyme levels and protein cost in natural and engineered pathways, and could be a valuable computational tool to assist metabolic engineering projects. Furthermore, it establishes a direct connection between protein cost and thermodynamics, and provides a physically plausible and computationally tractable way to include enzyme kinetics into constraint-based metabolic models, where kinetics have usually been ignored or

Diffuse fluxes of cosmic high-energy neutrinos

International Nuclear Information System (INIS)

Stecker, F.W.

1979-01-01

Production spectra of high-energy neutrinos from galactic cosmic-ray interactions with interstellar gas and extragalactic ultrahigh-energy cosmic-ray interactions with microwave blackbody photons are presented and discussed. These production processes involve the decay of charged pions and are thus related to the production of cosmic γ-rays from the decay of neutral pions. Estimates of the neutrino fluxes from various diffuse cosmic sources are then made, and the reasons for significant differences with previous estimates are discussed. Small predicted event rates for a DUMAND type detection system, combined with a possible significant flux of prompt neutrinos from the atmosphere above 50 TeV, may make the study of diffuse extraterrestrial neutrinos more difficult than previously thought

Final report of the HFIR [High Flux Isotope Reactor] irradiation facilities improvement project

International Nuclear Information System (INIS)

Montgomery, B.H.; Thoms, K.R.; West, C.D.

1987-09-01

The High-Flux Isotope Reactor (HFIR) has outstanding neutronics characteristics for materials irradiation, but some relatively minor aspects of its mechanical design severely limited its usefulness for that purpose. In particular, though the flux trap region in the center of the annular fuel elements has a very high neutron flux, it had no provision for instrumentation access to irradiation capsules. The irradiation positions in the beryllium reflector outside the fuel elements also have a high flux; however, although instrumented, they were too small and too few to replace the facilities of a materials testing reactor. To address these drawbacks, the HFIR Irradiation Facilities Improvement Project consisted of modifications to the reactor vessel cover, internal structures, and reflector. Two instrumented facilities were provided in the flux trap region, and the number of materials irradiation positions in the removable beryllium (RB) was increased from four to eight, each with almost twice the available experimental space of the previous ones. The instrumented target facilities were completed in August 1986, and the RB facilities were completed in June 1987

Multiobjective flux balancing using the NISE method for metabolic network analysis.

Science.gov (United States)

Oh, Young-Gyun; Lee, Dong-Yup; Lee, Sang Yup; Park, Sunwon

2009-01-01

Flux balance analysis (FBA) is well acknowledged as an analysis tool of metabolic networks in the framework of metabolic engineering. However, FBA has a limitation for solving a multiobjective optimization problem which considers multiple conflicting objectives. In this study, we propose a novel multiobjective flux balance analysis method, which adapts the noninferior set estimation (NISE) method (Solanki et al., 1993) for multiobjective linear programming (MOLP) problems. NISE method can generate an approximation of the Pareto curve for conflicting objectives without redundant iterations of single objective optimization. Furthermore, the flux distributions at each Pareto optimal solution can be obtained for understanding the internal flux changes in the metabolic network. The functionality of this approach is shown by applying it to a genome-scale in silico model of E. coli. Multiple objectives for the poly(3-hydroxybutyrate) [P(3HB)] production are considered simultaneously, and relationships among them are identified. The Pareto curve for maximizing succinic acid production vs. maximizing biomass production is used for the in silico analysis of various combinatorial knockout strains. This proposed method accelerates the strain improvement in the metabolic engineering by reducing computation time of obtaining the Pareto curve and analysis time of flux distribution at each Pareto optimal solution. (c) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009.

Analysis of the behavior of an experimental absorption heat transformer for water purification for different mass flux rates in the generator

International Nuclear Information System (INIS)

Huicochea, Armando; Rivera, Wilfrido; Martínez, Hiram; Siqueiros, Javier; Cadenas, Erasmo

2013-01-01

In the present study, first and second laws of thermodynamics have been used to analyse the performance of an experimental absorption heat transformer for water purification. Irreversibilities, coefficients of performance (COP) and exergy coefficients of performance (ECOP) were determined as function of the mass flow of hot water supplied to the generator and as function of the overall thermal specific energy consumption (OSTEC) parameter defined in this paper. The results showed that the system irreversibilities increase meanwhile the coefficients of performance and the exergy coefficient of performance decrease with an increment of the mass flow of hot water supplied to the generator. Also it was shown that the system performance is better when the production of purified water increases due to the increment of the heat recycled to the generator and evaporator. -- Highlights: ► Exergetic performance of an absorption heat transformer for purifying water to different mass flux rates in the generator. ► The irreversibilities are increasing when the mass flow rate in the generator is major. ► The mass flow rates in the generator plays a decisive role in the whole system efficiency

Criticality experiments to provide benchmark data on neutron flux traps

International Nuclear Information System (INIS)

Bierman, S.R.

1988-06-01

The experimental measurements covered by this report were designed to provide benchmark type data on water moderated LWR type fuel arrays containing neutron flux traps. The experiments were performed at the US Department of Energy Hanford Critical Mass Laboratory, operated by Pacific Northwest Laboratory. The experimental assemblies consisted of 2 /times/ 2 arrays of 4.31 wt % 235 U enriched UO 2 fuel rods, uniformly arranged in water on a 1.891 cm square center-to-center spacing. Neutron flux traps were created between the fuel units using metal plates containing varying amounts of boron. Measurements were made to determine the effect that boron loading and distance between the fuel and flux trap had on the amount of fuel required for criticality. Also, measurements were made, using the pulse neutron source technique, to determine the effect of boron loading on the effective neutron multiplications constant. On two assemblies, reaction rate measurements were made using solid state track recorders to determine absolute fission rates in 235 U and 238 U. 14 refs., 12 figs., 7 tabs

Partly standing internal tides in a dendritic submarine canyon observed by an ocean glider

Science.gov (United States)

Hall, Rob A.; Aslam, Tahmeena; Huvenne, Veerle A. I.

2017-08-01

An autonomous ocean glider is used to make the first direct measurements of internal tides within Whittard Canyon, a large, dendritic submarine canyon system that incises the Celtic Sea continental slope and a site of high benthic biodiversity. This is the first time a glider has been used for targeted observations of internal tides in a submarine canyon. Vertical isopycnal displacement observations at different stations fit a one-dimensional model of partly standing semidiurnal internal tides - comprised of a major, incident wave propagating up the canyon limbs and a minor wave reflected back down-canyon by steep, supercritical bathymetry near the canyon heads. The up-canyon internal tide energy flux in the primary study limb decreases from 9.2 to 2.0 kW m-1 over 28 km (a dissipation rate of 1 - 2.5 ×10-7 Wkg-1), comparable to elevated energy fluxes and internal tide driven mixing measured in other canyon systems. Within Whittard Canyon, enhanced mixing is inferred from collapsed temperature-salinity curves and weakened dissolved oxygen concentration gradients near the canyon heads. It has previously been hypothesised that internal tides impact benthic fauna through elevated near-bottom current velocities and particle resuspension. In support of this, we infer order 20 cm s-1 near-bottom current velocities in the canyon and observe high concentrations of suspended particulate matter. The glider observations are also used to estimate a 1 °C temperature range and 12 μmol kg-1 dissolved oxygen concentration range, experienced twice a day by organisms on the canyon walls, due to the presence of internal tides. This study highlights how a well-designed glider mission, incorporating a series of tide-resolving stations at key locations, can be used to understand internal tide dynamics in a region of complex topography, a sampling strategy that is applicable to continental shelves and slopes worldwide.

FLUX SENSOR EVALUATIONS AT THE ATR CRITICAL FACILITY

International Nuclear Information System (INIS)

Unruh, Troy; Rempe, Joy; Nigg, David; Imel, George; Harris, Jason; Bonebrake, Eric

2010-01-01

The Advanced Test Reactor (ATR) and the ATR Critical (ATRC) facilities lack real-time methods for detecting thermal neutron flux and fission reaction rates for irradiation capsules. Direct measurements of the actual power deposited into a test are now possible without resorting to complicated correction factors. In addition, it is possible to directly measure minor actinide fission reaction rates and to provide time-dependent monitoring of the fission reaction rate or fast/thermal flux during transient testing. A joint Idaho State University/Idaho National Laboratory ATR National Scientific User Facility (ATR NSUF) project was recently initiated to evaluate new real-time state-of-the-art in-pile flux detection sensors. Initially, the project is comparing the accuracy, response time, and long duration performance of French Atomic Energy Commission (CEA)-developed miniature fission chambers, specialized self-powered neutron detectors (SPNDs) by the Argentinean National Energy Commission (CNEA), specially developed commercial SPNDs, and back-to-back fission (BTB) chambers developed by Argonne National Laboratory (ANL). As discussed in this paper, specialized fixturing and software was developed by INL to facilitate these joint ISU/INL evaluations. Calculations were performed by ISU to assess the performance of and reduce uncertainties in flux detection sensors and compare data obtained from these sensors with existing integral methods employed at the ATRC. Ultimately, project results will be used to select the detector that can provide the best online regional ATRC power measurement. It is anticipated that project results may offer the potential to increase the ATRC's current power limit and its ability to perform low-level irradiation experiments. In addition, results from this effort will provide insights about the viability of using these detectors in the ATR. Hence, this effort complements current activities to improve ATR software tools, computational protocols

Role of recycling flux in gas fuelling in the Large Helical Device

International Nuclear Information System (INIS)

Miyazawa, J.; Masuzaki, S.; Yamada, H.

2004-01-01

The 'effective' fuelling efficiency of hydrogen gas puffing ranges from 10% to 50% in the Large Helical Device. A local increase in neutral particle pressure at the gas puff port was measured in the experiment. The pressure increase rate corresponds to ∼ 10% of the gas puff flux. The other 90% of the gas puff flux increases the density and/or the plasma outflow. A particle balance model reveals that the recycling flux estimated from the particle flux on the divertor plates increases during the gas puffing. It is shown that the high effective fuelling efficiency is possibly due to the large recycling flux. At the limit of small recycling flux, the effective fuelling efficiency decreases to ∼10%. In the helium gas puff discharge, the effective fuelling efficiency is larger than the hydrogen gas puffing and approaches 100%. This can be related to the large recycling coefficient of more than 0.95. (author)

Decoherence of Flux Qubits Coupled to Electronic Circuits

NARCIS (Netherlands)

Wilhelm, F.K.; Storcz, M.J.; van der Wal, C.H.; Harmans, C.J.P.M.; Mooij, J.E.

2003-01-01

On the way to solid-state quantum computing, overcoming decoherence is the central issue. In this contribution, we discuss the modeling of decoherence of a superonducting flux qubit coupled to dissipative electronic circuitry. We discuss its impact on single qubit decoherence rates and on the

Fast modeling of flux trapping cascaded explosively driven magnetic flux compression generators.

Science.gov (United States)

Wang, Yuwei; Zhang, Jiande; Chen, Dongqun; Cao, Shengguang; Li, Da; Liu, Chebo

2013-01-01

To predict the performance of flux trapping cascaded flux compression generators, a calculation model based on an equivalent circuit is investigated. The system circuit is analyzed according to its operation characteristics in different steps. Flux conservation coefficients are added to the driving terms of circuit differential equations to account for intrinsic flux losses. To calculate the currents in the circuit by solving the circuit equations, a simple zero-dimensional model is used to calculate the time-varying inductance and dc resistance of the generator. Then a fast computer code is programmed based on this calculation model. As an example, a two-staged flux trapping generator is simulated by using this computer code. Good agreements are achieved by comparing the simulation results with the measurements. Furthermore, it is obvious that this fast calculation model can be easily applied to predict performances of other flux trapping cascaded flux compression generators with complex structures such as conical stator or conical armature sections and so on for design purpose.

A simple heat transfer model for a heat flux plate under transient conditions

International Nuclear Information System (INIS)

Ryan, L.; Dale, J.D.

1985-01-01

Heat flux plates are used for measuring rates of heat transfer through surfaces under steady state and transient conditions. Their usual construction is to have a resistive layer bounded by thermopiles and an exterior layer for protection. If properly designed and constructed a linear relationship between the thermopile generated voltage and heat flux results and calibration under steady state conditions is straight forward. Under transient conditions however the voltage output from a heat flux plate cannot instantaneously follow the heat flux because of the thermal capacitance of the plate and the resulting time lag. In order to properly interpret the output of a heat flux plate used under transient conditions a simple heat transfer model was constructed and tested. (author)

Analytic flux formulas and tables of shielding functions

International Nuclear Information System (INIS)

Wallace, O.J.

1981-06-01

Hand calculations of radiation flux and dose rates are often useful in evaluating radiation shielding and in determining the scope of a problem. The flux formulas appropriate to such calculations are almost always based on the point kernel and allow for at most the consideration of laminar slab shields. These formulas often require access to tables of values of integral functions for effective use. Flux formulas and function tables appropriate to calculations involving homogeneous source regions with the shapes of lines, disks, slabs, truncated cones, cylinders, and spheres are presented. Slab shields may be included in most of these calculations, and the effect of a cylindrical shield surrounding a cylindrical source may be estimated. Detector points may be located axially, laterally, or interior to a cylindrical source. Line sources may be tilted with respect to a slab shield. All function tables are given for a wide range of arguments

Fast Flux Watch: A mechanism for online detection of fast flux networks

Directory of Open Access Journals (Sweden)

Basheer N. Al-Duwairi

2014-07-01

Full Text Available Fast flux networks represent a special type of botnets that are used to provide highly available web services to a backend server, which usually hosts malicious content. Detection of fast flux networks continues to be a challenging issue because of the similar behavior between these networks and other legitimate infrastructures, such as CDNs and server farms. This paper proposes Fast Flux Watch (FF-Watch, a mechanism for online detection of fast flux agents. FF-Watch is envisioned to exist as a software agent at leaf routers that connect stub networks to the Internet. The core mechanism of FF-Watch is based on the inherent feature of fast flux networks: flux agents within stub networks take the role of relaying client requests to point-of-sale websites of spam campaigns. The main idea of FF-Watch is to correlate incoming TCP connection requests to flux agents within a stub network with outgoing TCP connection requests from the same agents to the point-of-sale website. Theoretical and traffic trace driven analysis shows that the proposed mechanism can be utilized to efficiently detect fast flux agents within a stub network.

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

FLUX CANCELLATION AND THE EVOLUTION OF THE ERUPTIVE FILAMENT OF 2011 JUNE 7

Energy Technology Data Exchange (ETDEWEB)

Yardley, S. L.; Green, L. M.; Williams, D. R.; Van Driel-Gesztelyi, L.; Valori, G.; Dacie, S., E-mail: stephanie.yardley.13@ucl.ac.uk [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom)

2016-08-20

We investigate whether flux cancellation is responsible for the formation of a very massive filament resulting in the spectacular eruption on 2011 June 7. We analyze and quantify the amount of flux cancellation that occurs in NOAA AR 11226 and its two neighboring active regions (ARs 11227 and 11233) using line-of-sight magnetograms from the Heliospheric Magnetic Imager. During a 3.6 day period building up to the eruption of the filament, 1.7 × 10{sup 21} Mx, 21% of AR 11226's maximum magnetic flux, was canceled along the polarity inversion line (PIL) where the filament formed. If the flux cancellation continued at the same rate up until the eruption then up to 2.8 × 10{sup 21} Mx (34% of the AR flux) may have been built into the magnetic configuration that contains the filament plasma. The large flux cancellation rate is due to an unusual motion of the positive-polarity sunspot, which splits, with the largest section moving rapidly toward the PIL. This motion compresses the negative polarity and leads to the formation of an orphan penumbra where one end of the filament is rooted. Dense plasma threads above the orphan penumbra build into the filament, extending its length, and presumably injecting material into it. We conclude that the exceptionally strong flux cancellation in AR 11226 played a significant role in the formation of its unusually massive filament. In addition, the presence and coherent evolution of bald patches in the vector magnetic field along the PIL suggest that the magnetic field configuration supporting the filament material is that of a flux rope.

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.)

Increase in γ-ray flux at balloon altitude during magnetic disturbances

International Nuclear Information System (INIS)

Martin, I.M; Rai, D.B.; Palmeira, R.A.R.; Trivedi, N.B.; Costa, J.M. da.

1974-01-01

Balloon observations of γ-rays (0.9 - 18 MeV) and charged particle (>=0.7 MeV) flux made at Sao Jose dos campos (23 0 14'S, 45 0 51'W) on quiet and magnetically disturbed days in October 1973 are presented and discussed. The γ-ray flux during the disturbed period shows a considerable increase compared to the quiet day observations. The charged particles count rate also shows an increase but to a much smaller extent. The increase in the γ-ray flux is attributed to the bremsstrahlung of precipitating high energy electrons from the inner radiation belt. A spectral analysis of the count rate of γ-rays shows that the increase in the flux is more pronounced on the low energy end (0.9 - 20 MeV) of the spectrum which lends further support to the bremsstrahlung explanation. Based on the photon spectrum in the range 0.9 - 18 MeV the spectrum of the precipitating electron causing the γ-ray emission is calculated. The photon spectrum is of the form dN/dE α E sup( - 2.2) in the range 0.9 - 2.5 MeV and dN/dE approximately E sup( - 1.1) in the range 7.0 - 18 MeV. Thus it may be concluded that the increase in the γ-ray flux is due to the precipitation of electrons of the inner radiation belt with E > 20 MeV

Temporal fluxomics reveals oscillations in TCA cycle flux throughout the mammalian cell cycle.

Science.gov (United States)

Ahn, Eunyong; Kumar, Praveen; Mukha, Dzmitry; Tzur, Amit; Shlomi, Tomer

2017-11-06

Cellular metabolic demands change throughout the cell cycle. Nevertheless, a characterization of how metabolic fluxes adapt to the changing demands throughout the cell cycle is lacking. Here, we developed a temporal-fluxomics approach to derive a comprehensive and quantitative view of alterations in metabolic fluxes throughout the mammalian cell cycle. This is achieved by combining pulse-chase LC-MS-based isotope tracing in synchronized cell populations with computational deconvolution and metabolic flux modeling. We find that TCA cycle fluxes are rewired as cells progress through the cell cycle with complementary oscillations of glucose versus glutamine-derived fluxes: Oxidation of glucose-derived flux peaks in late G1 phase, while oxidative and reductive glutamine metabolism dominates S phase. These complementary flux oscillations maintain a constant production rate of reducing equivalents and oxidative phosphorylation flux throughout the cell cycle. The shift from glucose to glutamine oxidation in S phase plays an important role in cell cycle progression and cell proliferation. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

Non-linear Heart Rate Variability as a Discriminator of Internalizing Psychopathology and Negative Affect in Children With Internalizing Problems and Healthy Controls

Directory of Open Access Journals (Sweden)

Charlotte Fiskum

2018-05-01

Full Text Available Background: Internalizing psychopathology and dysregulated negative affect are characterized by dysregulation in the autonomic nervous system and reduced heart rate variability (HRV due to increases in sympathetic activity alongside reduced vagal tone. The neurovisceral system is however, a complex nonlinear system, and nonlinear indices related to psychopathology are so far less studied in children. Essential nonlinear properties of a system can be found in two main domains: the informational domain and the invariant domain. sample entropy (SampEn is a much-used method from the informational domain, while detrended fluctuation analysis (DFA represents a widely-used method from the invariant domain. To see if nonlinear HRV can provide information beyond linear indices of autonomic activation, this study investigated SampEn and DFA as discriminators of internalizing psychopathology and negative affect alongside measures of vagally-mediated HRV and sympathetic activation.Material and Methods: Thirty-Two children with internalizing difficulties and 25 healthy controls (aged 9–13 were assessed with the Child Behavior Checklist and the Early Adolescent Temperament Questionnaire, Revised, giving an estimate of internalizing psychopathology, negative affect and effortful control, a protective factor against psychopathology. Five minute electrocardiogram and impedance cardiography recordings were collected during a resting baseline, giving estimates of SampEn, DFA short-term scaling exponent α1, root mean square of successive differences (RMSSD, and pre-ejection period (PEP. Between-group differences and correlations were assessed with parametric and non-parametric tests, and the relationships between cardiac variables, psychopathology and negative affect were assessed using generalized linear modeling.Results: SampEn and DFA were not significantly different between the groups. SampEn was weakly negatively related to heart rate (HR in the controls

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux

Science.gov (United States)

Bowman, Charles D.

1992-01-01

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux. High thermal neutron fluxes generated from the action of a high power proton accelerator on a spallation target allows the efficient burn-up of higher actinide nuclear waste by a two-step process. Additionally, rapid burn-up of fission product waste for nuclides having small thermal neutron cross sections, and the practicality of small material inventories while achieving significant throughput derive from employment of such high fluxes. Several nuclear technology problems are addressed including 1. nuclear energy production without a waste stream requiring storage on a geological timescale, 2. the burn-up of defense and commercial nuclear waste, and 3. the production of defense nuclear material. The apparatus includes an accelerator, a target for neutron production surrounded by a blanket region for transmutation, a turbine for electric power production, and a chemical processing facility. In all applications, the accelerator power may be generated internally from fission and the waste produced thereby is transmuted internally so that waste management might not be required beyond the human lifespan.

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux

Science.gov (United States)

Bowman, C.D.

1992-11-03

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux. High thermal neutron fluxes generated from the action of a high power proton accelerator on a spallation target allows the efficient burn-up of higher actinide nuclear waste by a two-step process. Additionally, rapid burn-up of fission product waste for nuclides having small thermal neutron cross sections, and the practicality of small material inventories while achieving significant throughput derive from employment of such high fluxes. Several nuclear technology problems are addressed including 1. nuclear energy production without a waste stream requiring storage on a geological timescale, 2. the burn-up of defense and commercial nuclear waste, and 3. the production of defense nuclear material. The apparatus includes an accelerator, a target for neutron production surrounded by a blanket region for transmutation, a turbine for electric power production, and a chemical processing facility. In all applications, the accelerator power may be generated internally from fission and the waste produced thereby is transmuted internally so that waste management might not be required beyond the human lifespan.

The reversed and normal flux contributions to axial dipole decay for 1880-2015

Science.gov (United States)

Metman, M. C.; Livermore, P. W.; Mound, J. E.

2018-03-01

The axial dipole component of Earth's internal magnetic field has been weakening since at least 1840, an effect widely believed to be attributed to the evolution of reversed flux patches (RFPs). These are regions on the core-mantle boundary (CMB) where the sign of radial flux deviates from that of the dominant sign of hemispheric radial flux. We study dipole change over the past 135 years using the field models gufm1, COV-OBS.x1 and CHAOS-6; we examine the impact of the choice of magnetic equator on the identification of reversed flux, the contribution of reversed and normal flux to axial dipole decay, and how reversed and normal field evolution has influenced the axial dipole. We show that a magnetic equator defined as a null-flux curve of the magnetic field truncated at spherical harmonic degree 3 allows us to robustly identify reversed flux, which we demonstrate is a feature of at least degree 4 or 5. Additionally, our results indicate that the evolution of reversed flux accounts for approximately two-thirds of the decay of the axial dipole, while one third of the decay is attributed to the evolution of the normal field. We find that the decay of the axial dipole over the 20th century is associated with both the expansion and poleward migration of reversed flux patches. In contrast to this centennial evolution, changes in the structure of secular variation since epoch 2000 indicate that poleward migration currently plays a much reduced role in the ongoing dipole decay.

Calorimeter probes for measuring high thermal flux. [in arc jets

Science.gov (United States)

Russell, L. D.

1979-01-01

Expendable, slug-type calorimeter probes were developed for measuring high heat-flux levels of 10-30 kW/sq cm in electric-arc jet facilities. The probes were constructed with thin tungsten caps mounted on Teflon bodies. The temperature of the back surface of the tungsten cap is measured, and its time rate of change gives the steady-state absorbed heat flux as the calorimeter probe heats to destruction when inserted into the arc jet. Design, construction, test, and performance data are presented.

TRANSHEX, 2-D Thermal Neutron Flux Distribution from Epithermal Flux in Hexagonal Geometry

International Nuclear Information System (INIS)

Patrakka, E.

1994-01-01

1 - Description of program or function: TRANSHEX is a multigroup integral transport program that determines the thermal scalar flux distribution arising from a known epithermal flux in two- dimensional hexagonal geometry. 2 - Method of solution: The program solves the isotropic collision probability equations for a region-averaged scalar flux by an iterative method. Either a successive over-relaxation or an inner-outer iteration technique is applied. Flat flux collision probabilities between trigonal space regions with white boundary condition are utilized. The effect of epithermal flux is taken into consideration as a slowing-down source that is calculated for a given spatial distribution and 1/E energy dependence of the epithermal flux

Changing trends of rainfall and sediment fluxes in the Kinta River catchment, Malaysia

Directory of Open Access Journals (Sweden)

W. R. Ismail

2015-03-01

Full Text Available The Kinta River, draining an area of 2566 km2, originates in the Korbu Mountain in Perak, Malaysia, and flows through heterogeneous, mixed land uses ranging from extensive forests to mining, rubber and oil palm plantations, and urban development. A land use change analysis of the Kinta River catchment was carried out together with assessment of the long-term trend in rainfall and sediment fluxes. The Mann-Kendall test was used to examine and assess the long-term trends in rainfall and its relationship with the sediment discharge trend. The land use analysis shows that forests, water bodies and mining land declined whilst built and agricultural land use increased significantly. This has influenced the sediment flux of the catchment. However, most of the rainfall stations and river gauging stations are experiencing an increasing trends, except at Kinta river at Tg. Rambutan. Sediment flux shows a net erosion for the period from 1961 to 1969. The total annual sediment discharge in the Kinta River catchment was low with an average rate of 1,757 t/km2/year. From 1970 to 1985, the annual sediment yield rose to an average rate of 4062 t/km2/year. Afterwards, from 1986 to 1993, the total annual sediment discharge decreased to an average rate of 1,306 t/km2/year and increased back during the period 1994 to 2000 to 2109 t/km2/year. From 2001 to 2006 the average sediment flux rate declined to 865 t/km2/year. The decline was almost 80% from the 1970s. High sediment flux in the early 1970s is partly associated with reduced tin mining activities in the area. This decreasing trend in sediment delivery leaving the Kinta River catchment is expected to continue dropping in the future.

Changing trends of rainfall and sediment fluxes in the Kinta River catchment, Malaysia

Science.gov (United States)

Ismail, W. R.; Hashim, M.

2015-03-01

The Kinta River, draining an area of 2566 km2, originates in the Korbu Mountain in Perak, Malaysia, and flows through heterogeneous, mixed land uses ranging from extensive forests to mining, rubber and oil palm plantations, and urban development. A land use change analysis of the Kinta River catchment was carried out together with assessment of the long-term trend in rainfall and sediment fluxes. The Mann-Kendall test was used to examine and assess the long-term trends in rainfall and its relationship with the sediment discharge trend. The land use analysis shows that forests, water bodies and mining land declined whilst built and agricultural land use increased significantly. This has influenced the sediment flux of the catchment. However, most of the rainfall stations and river gauging stations are experiencing an increasing trends, except at Kinta river at Tg. Rambutan. Sediment flux shows a net erosion for the period from 1961 to 1969. The total annual sediment discharge in the Kinta River catchment was low with an average rate of 1,757 t/km2/year. From 1970 to 1985, the annual sediment yield rose to an average rate of 4062 t/km2/year. Afterwards, from 1986 to 1993, the total annual sediment discharge decreased to an average rate of 1,306 t/km2/year and increased back during the period 1994 to 2000 to 2109 t/km2/year. From 2001 to 2006 the average sediment flux rate declined to 865 t/km2/year. The decline was almost 80% from the 1970s. High sediment flux in the early 1970s is partly associated with reduced tin mining activities in the area. This decreasing trend in sediment delivery leaving the Kinta River catchment is expected to continue dropping in the future.

TAXATION AND INTERNAL MIGRATION - EVIDENCE FROM THE SWISS CENSUS USING COMMUNITY-LEVEL VARIATION IN INCOME TAX RATES

OpenAIRE

Liebig, Thomas; Puhani, Patrick A.; Sousa-Poza, Alfonso

2006-01-01

We investigate the relationship between income tax rate variation and internal migration for the unique case of Switzerland, whose system of determining tax rates primarily at the community level results in enough variation to permit analysis of their influence on migration. Specifically, using Swiss census data, we analyze migratory responses to tax rate variations for various groups defined by age, education, and nationality/residence permit. The results suggest that young Swiss college gra...

GCR flux 9-day variations with LISA Pathfinder

International Nuclear Information System (INIS)

Grimani, C; Benella, S; Fabi, M; Finetti, N; Telloni, D

2017-01-01

Galactic cosmic-ray (GCR) energy spectra in the heliosphere vary on the basis of the level of solar activity, the status of solar polarity and interplanetary transient magnetic structures of solar origin. A high counting rate particle detector (PD) aboard LISA Pathfinder (LPF) allows for the measurement of galactic cosmic-ray and solar energetic particle (SEP) integral fluxes at energies > 70 MeV n −1 up to 6500 counts s −1 . Data are gathered with a sampling time of 15 s. A study of GCR flux depressions associated with the third harmonic of the Sun rotation period (∼ 9 days) is presented here. (paper)

Carbon stocks and fluxes in managed peatlands in northern Borneo

Science.gov (United States)

Arn Teh, Yit; Manning, Frances; Cook, Sarah; Zin Zawawi, Norliyana; Sii, Longwin; Hill, Timothy; Page, Susan; Whelan, Mick; Evans, Chris; Gauci, Vincent; Chocholek, Melanie; Khoon Kho, Lip

2017-04-01

Oil palm is the largest agricultural crop in the tropics and accounts for 13 % of current tropical land area. Patterns of land-atmosphere exchange from oil palm ecosystems therefore have potentially important implications for regional and global C budgets due to the large scale of land conversion. This is particularly true for oil palm plantations on peat because of the large C stocks held by tropical peat soils that are potential sensitivity to human disturbance. Here we report preliminary findings on C stocks and fluxes from a long-term, multi-scale project in Sarawak, Malaysia that aims to quantify the impacts of oil palm conversion on C and greenhouse gas fluxes from oil palm recently established on peat. Land-atmosphere fluxes were determined using a combination of top-down and bottom-up methods (eddy covariance, canopy/stem and soil flux measurements, net primary productivity). Fluvial fluxes were determined by quantifying rates of dissolved and particulate organic C export. Ecosystem C dynamics were determined using the intensive C plot method, which quantified all major C stocks and fluxes, including plant and soil stocks, leaf litterfall, aboveground biomass production, root production, stem/canopy respiration, root-rhizosphere respiration, and heterotrophic soil respiration. Preliminary analysis indicates that vegetative aboveground biomass in these 7 year old plantations was 8.9-11.9 Mg C ha-1, or approximately one-quarter of adjacent secondary forest. Belowground biomass was 5.6-6.5 Mg C ha-1; on par with secondary forests. Soil C stocks in the 0-30 cm depth was 233.1-240.8 Mg C ha-1, or 32-36% greater than soil C stocks in secondary forests at the same depth (176.8 Mg C ha-1). Estimates of vegetative aboveground and belowground net primary productivity were 1.3-1.7 Mg C ha-1 yr-1 and 0.8-0.9 Mg C ha-1 yr-1, respectively. Fruit brunch production was approximately 67 Mg C ha-1over 7 yearsor 9.6 Mg C ha-1 yr-1. Total soil respiration rates were 18 Mg C ha

Investigation of aeration rate on Uranium bio leaching in internal airlift bioreactor

International Nuclear Information System (INIS)

Zolala, M. R.; Safdari, S. J.; Haghighi Asl, A.; Rashidi, A.

2012-01-01

Uranium is leached from the uranium ore of the second anomaly of Saghand by the Acidithiobacillus ferroxidans bacteria in an internal airlift bio-reactor. This study has been made to find the effect of aeration rate as well as its optimal value. The experiments have been carried out at 4 aeration rates to find the best recovery results in the least possible time duration. The results showed that the most percentage of the uranium recovery is in the superficial gas velocity of 0.010 m/s. The recovery at this aeration rate has an efficiency of more than 95 p ercent i n 11 days. Also, the best range for aeration study in the airlift bio-reactor is calculated with a minimum value of 0.0065 m/s which is the critical value of the uranium particle suspension as well as the maximum value of 0.015 m/s. The stress on the bacteria increases the recovery time process in velocities of more than 0.015 m/s.

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

Mantle convective support, drainage patterns and sedimentary flux: Examples from the West Africa passive margin

Science.gov (United States)

Lodhia, B. H.; Roberts, G. G.; Fraser, A.; Goes, S. D. B.; Fishwick, S.; Jarvis, J.

2017-12-01

Sedimentary flux measurements, regional subsidence patterns, inversion of drainage patterns, tomographic models and simple isostatic calculations are combined to constrain the history of sub-plate support of North West Africa. Backstripping of 8 commercial wells and mapping of 53,000 line-km of 2D seismic reflection data show that rapid ( 0.03 mm a-1) Neogene-Recent subsidence occurred in a 500 x 500 km region offshore Mauritania. 0.4-0.8 km of water-loaded subsidence occurred in the center of the basin during the last 23 Ma. Salt withdrawal, thin-skinned tectonics, glacio-eustasy and flexure of the lithosphere due to the emplacement of Cape Verde cannot explain the timing or magnitude of this phase of subsidence. Instead, conversion of shear wave velocities into temperature and simple isostatic calculations indicate that asthenospheric temperatures determine bathymetry from Cape Verde to West Africa. Our results indicate that asthenospheric flow from Cape Verde to Mauritania generated a bathymetric gradient of 1/300 at a wavelength of 103 km during the last 23 Ma. We explore the relationship between uplift and erosion onshore and measured solid sedimentary flux offshore. First, the history of sedimentary flux to the margin was determined by depth-converting and decompacting biostratigraphically-dated isopachs. Compaction and velocity errors, determined using check-shot data, were propagated into calculated sedimentary flux history. Solid-sedimentary flux rates of 0.2-0.1+0.2 ×103 km3 /Ma between 23.8-5.6 Ma, and 1.9-1.4+2.0 ×103 km3 /Ma from 5.6-0 Ma are observed. Secondly, a calibrated stream power erosional model was used to invert 14700 river profiles for a history of regional uplift rate. Incision rates were integrated along best-fitting theoretical river profiles to predict sedimentary flux at mouths of the rivers draining NW Africa. Our predicted history of sedimentary flux increases in two stages towards the present-day, in agreement with our offshore

Characteristics of Flux Decline in Forward Osmosis Process for Asymmetric Cellulose Membrane

Energy Technology Data Exchange (ETDEWEB)

Han, Myeong-Jin; Nam, Suk-Tae [Kyungil University, Gyeongsan (Korea, Republic of); Lee, Keun-Woo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-06-15

This study examined the effect of concentration polarization on permeate flux in forward osmosis (FO) membrane process for saline and sucrose solution. The reduction in permeate flux during the FO membrane process is largely due to the formation of concentration polarization on membrane surfaces. The flux reduction due to internal concentration polarization formed on the porous support layer was larger than that due to the external concentration polarization on the active membrane surface. Water permeate flux through the FO membrane increased nonlinearly with the increase in osmotic pressure. The water permeability coefficient was 1.8081x10{sup -7} m/s·atm for draw solution on active layer (DS-AL) mode and 1.0957-10{sup -7} m/s·atm for draw solution on support layer (DS-SL) mode in NaCl solution system. The corresponding membrane resistance was 5.5306x10{sup 6} and 9.1266x10{sup 6} s·atm/m, respectively. With respect to the sucrose solution, the permeate flux for DS-AL mode was 1.33-1.90 times higher than that for DS-SL mode. The corresponding variation in the permeation flux (J) due to osmotic pressure (π) would be expressed as J=-0.0177+0.4506π-0.0032π{sup 2} for the forward and J=0.0948+0.3292π-0.0037π{sup 2} for the latter.

Observation of radiation environment in the International Space Station in 2012–March 2013 by Liulin-5 particle telescope

Directory of Open Access Journals (Sweden)

Semkova Jordanka

2014-01-01

Full Text Available Since June 2007 the Liulin-5 charged particle telescope, located in the spherical tissue-equivalent phantom of the MATROSHKA-R project onboard the International Space Station (ISS, has been making measurements of the local energetic particle radiation environment. From 27 December 2011 to 09 March 2013 measurements were conducted in and outside the phantom located in the MIM1 module of the ISS. In this paper Liulin-5 dose rates, due to galactic cosmic rays and South Atlantic Anomaly trapped protons, measured during that period are presented. Particularly, dose rates and particle fluxes for the radiation characteristics in the phantom during solar energetic particle (SEP events occurring in March and May 2012 are discussed. Liulin-5 SEP observations are compared with other ISS data, GOES proton fluxes as well as with solar energetic particle measurements obtained onboard the Mir space station during previous solar cycles.

Flux estimation algorithms for electric drives: a comparative study