Science.gov

Sample records for natural circulation calculations

  1. Thermalhydraulic calculation for boiling water reactor and its natural circulation component

    SciTech Connect

    Trianti, Nuri Nurjanah,; Su’ud, Zaki; Arif, Idam; Permana, Sidik

    2015-09-30

    Thermalhydraulic of reactor core is the thermal study on fluids within the core reactor, i.e. analysis of the thermal energy transfer process produced by fission reaction from fuel to the reactor coolant. This study include of coolant temperature and reactor power density distribution. The purposes of this analysis in the design of nuclear power plant are to calculate the coolant temperature distribution and the chimney height so natural circulation could be occurred. This study was used boiling water reactor (BWR) with cylinder type reactor core. Several reactor core properties such as linear power density, mass flow rate, coolant density and inlet temperature has been took into account to obtain distribution of coolant density, flow rate and pressure drop. The results of calculation are as follows. Thermal hydraulic calculations provide the uniform pressure drop of 1.1 bar for each channels. The optimum mass flow rate to obtain the uniform pressure drop is 217g/s. Furthermore, from the calculation it could be known that outlet temperature is 288°C which is the saturated fluid’s temperature within the system. The optimum chimney height for natural circulation within the system is 14.88 m.

  2. Calculation of the Phenix end-of-life test in natural circulation with the CATHARE code

    SciTech Connect

    Maas, L.; Cocheme, F.

    2012-07-01

    The Inst. of Radiological Protection and Nuclear Safety (IRSN) acts as technical support to French public authorities. As such, IRSN is in charge of safety assessment of operating and under construction reactors, as well as future projects. In this framework, one current objective of IRSN is to evaluate the ability and accuracy of numerical tools to foresee consequences of accidents. One of the advantages pointed up for fast reactors cooled by heavy liquid metal is the possibility of decay heat removal based on natural convection. The promotion of this passive cooling mode in future safety demonstrations will involve the use of adapted and validated numerical codes. After the final shutdown of the Phenix sodium cooled fast reactor in 2009, a set of tests covering different areas was conducted for code validation, including a natural circulation test in the primary circuit. Experimental data were issued by CEA to organize a benchmark exercise in the frame of an IAEA Coordinated Research Project (CRP), with the objective to assess the system-codes capability in simulating the thermal-hydraulics behavior of sodium cooled fast reactors in such accidental conditions. IRSN participated to this benchmark with the CATHARE code. This code, co-developed by CEA, EDF, AREVA and IRSN and widely used for PWR safety studies, was recently extended for sodium applications. This paper presents the CATHARE modeling of the Phenix primary circuit and the results obtained. A relatively good agreement was found with available measurements considering the experimental uncertainties. This work stressed the local aspects of phenomena occurring during the natural convection establishment and the limits of a 0D/1D approach. (authors)

  3. Thermohydraulic model experiments and calculations on the transition from forced to natural circulation for pool-type fast reactors

    SciTech Connect

    Hoffmann, H.; Marten, K.; Weinberg, D.; Kamide, H.

    1990-01-01

    After a reactor scram, the decay heat removal (DHR) is of decisive importance for the safety of the plant. A fully passive DHR system based on natural circulation alone is independent of any power source. The DHE system consists of immersion coolers (ICs) installed in the hot plenum and connected to air coolers, each via intermediate circuits. During the postscram phase, the decay heat is to be removed by natural circulation from the core into the hot plenum and via the ICs and intermediate loops to the air coolers. The function of this DHR system is investigated and demonstrated in model tests with a geometry similar to the reactor, though on a different scale RAMONA is such a three-dimensional model set up on a 1:20 scale. It is operated with water. The steady-state tests for natural-circulation DHR operations have been conducted over a wide range of operational and geometric parameters. To study the transition from nominal to DHR conditions, experiments were defined to investigate the onset of natural circulation in the postscram phase (transient tests). The experiments were analyzed using the one-dimensional LEDHER code. LEDHER is a network analysis code for the long-term DHR of a fast reactor developed at Power Reactor and Nuclear Fuel Development Corporation in Japan. The results of the experiments and conclusions are summarized.

  4. Validation of SSC using the FFTF natural-circulation tests

    SciTech Connect

    Horak, W.C.; Guppy, J.G.; Kennett, R.J.

    1982-01-01

    As part of the Super System Code (SSC) validation program, the 100% power FFTF natural circulation test has been simulated using SSC. A detailed 19 channel, 2 loop model was used in SSC. Comparisons showed SSC calculations to be in good agreement with the Fast Flux Test Facility (FFTF), test data. Simulation of the test was obtained in real time.

  5. Quenching phenomena in natural circulation loop

    SciTech Connect

    Umekawa, Hisashi; Ozawa, Mamoru; Ishida, Naoki

    1995-09-01

    Quenching phenomena has been investigated experimentally using circulation loop of liquid nitrogen. During the quenching under natural circulation, the heat transfer mode changes from film boiling to nucleate boiling, and at the same time flux changes with time depending on the vapor generation rate and related two-phase flow characteristics. Moreover, density wave oscillations occur under a certain operating condition, which is closely related to the dynamic behavior of the cooling curve. The experimental results indicates that the occurrence of the density wave oscillation induces the deterioration of effective cooling of the heat surface in the film and the transition boiling regions, which results in the decrease in the quenching velocity.

  6. Calculated Hovering Helicopter Flight Dynamics with a Circulation Controlled Rotor

    NASA Technical Reports Server (NTRS)

    Johnson, W.; Chopra, I.

    1977-01-01

    The influence of the rotor blowing coefficient on the calculated roots of the longitudinal and lateral motion was examined for a range of values of the rotor lift and the blade flap frequency. The control characteristics of a helicopter with a circulation controlled rotor are discussed. The principal effect of the blowing is a reduction in the rotor speed stability derivative. Above a critical level of blowing coefficient, which depends on the flap frequency and rotor lift, negative speed stability is produced and the dynamic characteristics of the helicopter are radically altered.

  7. RELAP5 assessment: PKL natural-circulation tests. [PWR; BWR

    SciTech Connect

    Thompson, S.L.; Kmetyk, L.N.

    1983-01-01

    The RELAP5 independent assessment project at Sandia National Laboratories is part of an overall effort funded by the NRC to determine the ability of various system codes to predict the detailed thermal-hydraulic response of LWR's during accident and off-normal conditions. The RELAP5 code is being assessed at SNLA against test data from various integral and separate effects tests facilities. As part of this assessment matrix a series of natural circulation tests performed at the PKL facility have been analyzed. The results show that RELAP5 will qualitatively describe all modes of natural circulation (including reflux cooling), although there are several quantitative discrepancies.

  8. Uncertainty in calculating vorticity from 2D velocity fields using circulation and least-squares approaches

    NASA Astrophysics Data System (ADS)

    Abrahamson, S.; Lonnes, S.

    1995-11-01

    The most common method for determining vorticity from planar velocity information is the circulation method. Its performance has been evaluated using a plane of velocity data obtained from a direct numerical simulation (DNS) of a three dimensional plane shear layer. Both the ability to reproduce the vorticity from the exact velocity field and one perturbed by a 5% random “uncertainty” were assessed. To minimize the sensitivity to velocity uncertainties, a new method was developed using a least-squares approach. The local velocity data is fit to a model velocity field consisting of uniform translation, rigid rotation, a point source, and plane shear. The least-squares method was evaluated in the same manner as the circulation method. The largest differences between the actual and calculated vorticity fields were due to the filter-like nature of the methods. The new method is less sensitive to experimental uncertainty. However the circulation method proved to be slightly better at reproducing the DNS field. The least-squares method provides additional information beyond the circulation method results. Using the correlation overline {Pω ω } and a vorticity threshold criteria to identify regions of rigid rotation (or eddies), the rigid rotation component of the least-squares method indicates these same regions.

  9. A study of natural circulation in the evaporator of a horizontal-tube heat recovery steam generator

    NASA Astrophysics Data System (ADS)

    Roslyakov, P. V.; Pleshanov, K. A.; Sterkhov, K. V.

    2014-07-01

    Results obtained from investigations of stable natural circulation in an intricate circulation circuit with a horizontal layout of the tubes of evaporating surface having a negative useful head are presented. The possibility of making a shift from using multiple forced circulation organized by means of a circulation pump to natural circulation in vertical heat recovery steam generator is estimated. Criteria for characterizing the performance reliability and efficiency of a horizontal evaporator with negative useful head are proposed. The influence of various design solutions on circulation robustness is considered. With due regard of the optimal parameters, the most efficient and least costly methods are proposed for achieving more stable circulation in a vertical heat recovery steam generator when a shift is made from multiple forced to natural circulation. A procedure for calculating the circulation parameters and an algorithm for checking evaporator performance reliability are developed, and recommendations for the design of heat recovery steam generator, nonheated parts of natural circulation circuit, and evaporating surface are suggested.

  10. Liquid Fluoride Salt Experimentation Using a Small Natural Circulation Cell

    SciTech Connect

    Yoder Jr, Graydon L; Heatherly, Dennis Wayne; Williams, David F; Elkassabgi, Yousri M.; Caja, Joseph; Caja, Mario; Jordan, John; Salinas, Roberto

    2014-04-01

    A small molten fluoride salt experiment has been constructed and tested to develop experimental techniques for application in liquid fluoride salt systems. There were five major objectives in developing this test apparatus: Allow visual observation of the salt during testing (how can lighting be introduced, how can pictures be taken, what can be seen) Determine if IR photography can be used to examine components submerged in the salt Determine if the experimental configuration provides salt velocity sufficient for collection of corrosion data for future experimentation Determine if a laser Doppler velocimeter can be used to quantify salt velocities. Acquire natural circulation heat transfer data in fluoride salt at temperatures up to 700oC All of these objectives were successfully achieved during testing with the exception of the fourth: acquiring velocity data using the laser Doppler velocimeter. This paper describes the experiment and experimental techniques used, and presents data taken during natural circulation testing.

  11. On the stability of natural circulation loops with phase change

    NASA Astrophysics Data System (ADS)

    Haskin, Troy C.

    The stability of a simple, closed-loop, water-cooled natural circulation system was characterized over a range of single phase and two-phase states. The motivation for this investigation is a Next Generation Nuclear Plant safety cooling system called the Reactor Cavity Cooling System (RCCS). One of the proposed designs for the RCCS is a closed-circuit of network piping using water as a working fluid. One of the safety considerations for such a system is the stability of the system at steady-state under a large number of unknown states. This work provides a derivation of the commonly used one-dimensional conservation laws used in thermohydraulic system modeling and a novel discretization scheme that allows for exact integration of the computational domain for accurate calculation of eigenvalues of a linearized system. The steady-state solution of the discretized equations is then performed using a fully nonlinear Jacobian-Free Newton Krylov Method for a number of temperatures, pressures, and heat loads both in single and two-phase conditions. All of the single and two-phase state exhibit linear stability to small perturbations in values. The linear stability is also found to increase with increasing heat load due to the greater inertia of the system damping out small perturbation effectively and with increasing pressure due to the greater stiffness of the fluid. Nonlinear stability was also examined for a point power insertion of varying intensity from two steady-states. The loop exhibited stability for all power insertions from both steady-states, returning to the initial steady value shortly after the pulse.

  12. Natural Circulation Patterns in the VHTR Air-Ingress Accident and Related Issues

    SciTech Connect

    Chang Ho Oh; Eung Soo Kim; Hyung Seok Kang

    2010-10-01

    A natural circulation pattern in a Very High Gas-Cooled Reactor during a hypothetical air-ingress accident has been investigated using computational fluid dynamic (CFD) methods in order to compare with the previous 1-D flow path model for the air-ingress analyses. The GT-MHR 600 MWt reactor was selected to be the reference design and modeled by a half symmetric 3-D geometry using FLUENT 6.3, a commercial CFD code. The simulation was carried out as steady-state calculations, and the boundary conditions were either assumed or provided from the 1-D GAMMA code results. Totally, 12 different cases have been estimated, and many notable findings and results have been obtained in this study. According to the simulations, the natural circulation pattern in the reactor was quite different from the previous 1-D assumptions. A large re-circulation flow with thermal stratification phenomena was clearly observed in the hot-leg and the lower plenum in the 3-D model. This re-circulation flow provided approximately an order faster air-ingress speed (0.46 m/s in superficial velocity) than previously predicted values by 1-D modeling (0.02~0.03 m/s). It indicates that the 1-D air-ingress modeling may significantly distort the air-ingress scenario and consequences. In addition, the complicated natural circulation pattern is eventually expected to lead to very complex graphite oxidations and corrosion patterns.

  13. Control of natural circulation loops by electrohydrodynamic pumping

    NASA Astrophysics Data System (ADS)

    Grassi, W.; Testi, D.; Della Vista, D.

    2014-04-01

    The paper analyses the effect of electrohydrodynamic (EHD) pumping on the control of natural circulation loops (NCLs). The two major objectives of the investigation are: finding the optimal configuration of an EHD pump and demonstrating that the NCL flow direction can be inverted by exploiting the EHD phenomena. In the initial experimental set-up, we measured the static pressure rise given by an EHD pump made of three consecutive modules of point-ring electrodes for different dielectric fluids and electrode materials. When reversing the polarity of the applied DC voltage, we observed opposite pumping directions, suggesting the presence of two distinct EHD phenomena, inducing motion on opposite directions: ion-drag pumping and conduction pumping. The former was identified as a more efficient process compared to the latter. Based on these preliminary experiments, we built a NCL, operating with the fluid HFE-7100. Two oppositely mounted optimised pumping sections could be alternately activated, to promote clockwise or anticlockwise motion. In the first series of tests, alternately, the pumping sections were triggered prior to the heat input. In any case, the circulation followed the EHD pumping direction. In other tests, the electric field was applied when natural circulation was already present and the flow was reversed by means of opposite EHD pumping, at both polarities. Simply inverting the polarity of the applied voltage, we could alternate ion-drag and conduction pumping; in this way, we easily controlled the direction of motion by means of a single EHD pumping device.

  14. Pattern of Circulation of Norovirus GII Strains during Natural Infection

    PubMed Central

    Fobisong, Cajetan; Tah, Ferdinand; Lindh, Magnus; Nkuo-Akenji, Theresia; Bergström, Tomas

    2014-01-01

    Norovirus (NoV) is considered a major cause of nonbacterial gastroenteritis among people of all ages worldwide, but the natural course of infection is incompletely known. In this study, the pattern of circulation of NoVs was studied among 146 children and 137 adults in a small community in southwestern Cameroon. The participants provided monthly fecal samples during a year. NoV RNA was detected in at least one sample from 82 (29%) of the participants. The partial VP1 region could be sequenced in 36 NoV GII-positive samples. Three different genotypes were identified (GII.1, GII.4, and GII.17), with each genotype circulating within 2 to 3 months and reappearing after a relapse period of 2 to 3 months. Most infections occurred once, and 2 episodes at most within a year were detected. No difference in the frequency of NoV infection between children and adults was recorded. The same genotype was detected for a maximum of 2 consecutive months in 3 children only, suggesting that a less than 30-day duration of viral shedding in natural infection was common. Reinfection within a year with the same genotype was not observed, consistent with short-term homotypic immune protection. The study revealed that NoV strains are circulating with a limited duration of viral shedding both in the individuals and the population as part of their natural infection. The results also provide evidence of cross-protective immunity of limited duration between genotypes of the same genogroup. PMID:25274996

  15. MODELING STRATEGIES TO COMPUTE NATURAL CIRCULATION USING CFD IN A VHTR AFTER A LOFA

    SciTech Connect

    Yu-Hsin Tung; Richard W. Johnson; Ching-Chang Chieng; Yuh-Ming Ferng

    2012-11-01

    A prismatic gas-cooled very high temperature reactor (VHTR) is being developed under the next generation nuclear plant program (NGNP) of the U.S. Department of Energy, Office of Nuclear Energy. In the design of the prismatic VHTR, hexagonal shaped graphite blocks are drilled to allow insertion of fuel pins, made of compacted TRISO fuel particles, and coolant channels for the helium coolant. One of the concerns for the reactor design is the effects of a loss of flow accident (LOFA) where the coolant circulators are lost for some reason, causing a loss of forced coolant flow through the core. In such an event, it is desired to know what happens to the (reduced) heat still being generated in the core and if it represents a problem for the fuel compacts, the graphite core or the reactor vessel (RV) walls. One of the mechanisms for the transport of heat out of the core is by the natural circulation of the coolant, which is still present. That is, how much heat may be transported by natural circulation through the core and upwards to the top of the upper plenum? It is beyond current capability for a computational fluid dynamic (CFD) analysis to perform a calculation on the whole RV with a sufficiently refined mesh to examine the full potential of natural circulation in the vessel. The present paper reports the investigation of several strategies to model the flow and heat transfer in the RV. It is found that it is necessary to employ representative geometries of the core to estimate the heat transfer. However, by taking advantage of global and local symmetries, a detailed estimate of the strength of the resulting natural circulation and the level of heat transfer to the top of the upper plenum is obtained.

  16. Study of natural circulation in a VHTR after a LOFA using different turbulence models

    SciTech Connect

    Yu-Hsin Tung; Yuh-Ming Ferng; Richard W. Johnson; Ching-Chang Chieng

    2013-10-01

    Natural convection currents in the core are anticipated in the event of the failure of the gas circulator in a prismatic gas-cooled very high temperature reactor (VHTR). The paths that the helium coolant takes in forming natural circulation loops and the effective heat transport are of interest. The heated flow in the reactor core is turbulent during normal operating conditions and at the beginning of the LOFA with forced convection, but the flow may significantly be slowed down after the event and laminarized with mixed convection. In the present study, the potential occurrence and effective heat transport of natural circulation are demonstrated using computational fluid dynamic (CFD) calculations with different turbulence models as well as laminar flow. Validations and recommendation on turbulence model selection are conducted. The study concludes that large loop natural convection is formed due to the enhanced turbulence levels by the buoyancy effect and the turbulent regime near the interface of upper plenum and flow channels increases the flow resistance for channel flows entering upper plenum and thus less heat can be removed from the core than the prediction by laminar flow assumption.

  17. Modeling of a coal-fired natural circulation boiler

    SciTech Connect

    Bhambare, K.S.; Mitra, S.K.; Gaitonde, U.N.

    2007-06-15

    Modeling of a natural circulation boiler for a coal-fired thermal power station is presented here. The boiler system is divided into seven subcomponents, and for each section, models based on conservation of mass, momentum, and energy are formulated. The pressure drop at various sections and the heat transfer coefficients are computed using empirical correlations. Solutions are obtained by using SIMULINK. The model is validated by comparing its steady state and dynamic responses with the actual plant data. Open loop responses of the model to the step changes in the operating parameters, such as pressure, temperature, steam flow, feed water flow, are also analyzed. The present model can be used for the development and design of effective boiler control systems.

  18. Design study of lead bismuth cooled fast reactors and capability of natural circulation

    NASA Astrophysics Data System (ADS)

    Oktamuliani, Sri; Su'ud, Zaki

    2015-09-01

    A preliminary study designs SPINNOR (Small Power Reactor, Indonesia, No On-Site Refueling) liquid metal Pb-Bi cooled fast reactors, fuel (U, Pu)N, 150 MWth have been performed. Neutronic calculation uses SRAC which is designed cylindrical core 2D (R-Z) 90 × 135 cm, on the core fuel composed of heterogeneous with percentage difference of PuN 10, 12, 13% and the result of calculation is effective neutron multiplication 1.0488. Power density distribution of the output SRAC is generated for thermal hydraulic calculation using Delphi based on Pascal language that have been developed. The research designed a reactor that is capable of natural circulation at inlet temperature 300 °C with variation of total mass flow rate. Total mass flow rate affect pressure drop and temperature outlet of the reactor core. The greater the total mass flow rate, the smaller the outlet temperature, but increase the pressure drop so that the chimney needed more higher to achieve natural circulation or condition of the system does not require a pump. Optimization of the total mass flow rate produces optimal reactor design on the total mass flow rate of 5000 kg/s with outlet temperature 524,843 °C but require a chimney of 6,69 meters.

  19. Design study of lead bismuth cooled fast reactors and capability of natural circulation

    SciTech Connect

    Oktamuliani, Sri Su’ud, Zaki

    2015-09-30

    A preliminary study designs SPINNOR (Small Power Reactor, Indonesia, No On-Site Refueling) liquid metal Pb-Bi cooled fast reactors, fuel (U, Pu)N, 150 MWth have been performed. Neutronic calculation uses SRAC which is designed cylindrical core 2D (R-Z) 90 × 135 cm, on the core fuel composed of heterogeneous with percentage difference of PuN 10, 12, 13% and the result of calculation is effective neutron multiplication 1.0488. Power density distribution of the output SRAC is generated for thermal hydraulic calculation using Delphi based on Pascal language that have been developed. The research designed a reactor that is capable of natural circulation at inlet temperature 300 °C with variation of total mass flow rate. Total mass flow rate affect pressure drop and temperature outlet of the reactor core. The greater the total mass flow rate, the smaller the outlet temperature, but increase the pressure drop so that the chimney needed more higher to achieve natural circulation or condition of the system does not require a pump. Optimization of the total mass flow rate produces optimal reactor design on the total mass flow rate of 5000 kg/s with outlet temperature 524,843 °C but require a chimney of 6,69 meters.

  20. Assessment of RELAP5/MOD2 against a natural circulation experiment in Nuclear Power Plant Borssele. International Agreement Report

    SciTech Connect

    Winters, L.

    1993-07-01

    As part of the ICAP (International Code Assessment and Applications Program) agreement between ECN (Netherlands Energy Research Foundation) and USNRC, ECN has performed a number of assessment calculations for the thermohydraulic system analysis code RELAP5/MOD2/36.05. This document describes the assessment of this computer program versus a natural circulation experiment as conducted at the Borssele Nuclear Power Plant. The results of this comparison show that the code RELAP5/MOD2 predicts well the natural circulation behaviour of Nuclear Power Plant Borssele.

  1. Investigation of natural circulation instability and transients in passively safe novel modular reactor

    NASA Astrophysics Data System (ADS)

    Shi, Shanbin

    -hydraulic and nuclear coupled startup transients are performed to investigate the flow instabilities at low pressure and low power conditions. Two different power ramps are chosen to study the effect of power density on the flow instability. The experimental startup transient tests show the existence of three different flow instability mechanisms during the low pressure startup transients, i.e., flashing instability, condensation induced instability, and density wave oscillations. Flashing instability in the chimney section of the test loop and density wave oscillation are the main flow instabilities observed when the system pressure is below 0.5 MPa. They show completely different type of oscillations, i.e., intermittent oscillation and sinusoidal oscillation, in void fraction profile during the startup transients. In order to perform nuclear-coupled startup transients with void reactivity feedback, the Point Kinetics model is utilized to calculate the transient power during the startup transients. In addition, the differences between the electric resistance heaters and typical fuel element are taken into account. The reactor power calculated shows some oscillations due to flashing instability during the transients. However, the void reactivity feedback does not have significant influence on the flow instability during the startup procedure for the NMR-50. Further investigation of very small power ramp on the startup transients is carried out for the thermal-hydraulic startup transients. It is found that very small power density can eliminate the flashing oscillation in the single phase natural circulation and stabilize the flow oscillations in the phase of net vapor generation. Furthermore, initially pressurized startup procedure is investigated to eliminate the main flow instabilities. The results show that the pressurized startup procedure can suppress the flashing instability at low pressure and low power conditions. In order to have a deep understanding of natural

  2. Calculation and Analysis of Heat Transfer Coefficients in a Circulating Fluidized Bed Boiler Furnace

    NASA Astrophysics Data System (ADS)

    Wang, Zhiwei; Yang, Jianhua; Li, Qinghai

    A new way for the circulating fluidized bed (CFB) boiler research is proposed by the supervisory information system (SIS) in power plant level. The heat transfer coefficient in CFB boiler furnace is calculated and analyzed by the SIS calculation analysis in a commercial CFB boiler, the way how to calculate the heat transfer coefficient in SIS is introduced, and the heat transfer coefficient is accurately received by calculating a large amount of data from database. The relation about the heat transfer coefficient to unit load, bed temperature, bed velocity, and suspension density is analyzed; the linear relation could be accepted for the commercial CFB design. A new calculating and simple way for the heat transfer coefficient of CFB boiler is proposed for CFB boiler design. Using this research result, the reheat spray water flux larger than the design value in lots of commercial CFB boilers is analyzed; the main reason is the designed heat transfer coefficient smaller than the actual value.

  3. Infrared cooling rate calculations in operational general circulation models - Comparisons with benchmark computations

    NASA Technical Reports Server (NTRS)

    Kiehl, J. T.; Lacis, A. A.; Schwarzkopf, M. D.; Fels, S. B.

    1991-01-01

    The performance of several parameterized models is described with respect to numerical prediction and climate research at GFDL, NCAR, and GISS. The radiation codes of the models were compared to benchmark calculations and other codes for the intercomparison of radiation codes in climate models (ICRCCM). Cooling rates and fluxes calculated from the models are examined in terms of their application to established general circulation models (GCMs) from the three research institutions. The newest radiation parameterization techniques show the most significant agreement with the benchmark line-by-line (LBL) results. The LBL cooling rates correspond to cooling rate profiles from the models, but the parameterization of the water vapor continuum demonstrates uncertain results. These uncertainties affect the understanding of some lower tropospheric cooling, and therefore more accurate parameterization of the water vapor continuum, as well as the weaker absorption bands of CO2 and O3 is recommended.

  4. [Magnetic field numerical calculation and analysis for magnetic coupling of centrifugal blood pump for extracorporeal circulation].

    PubMed

    Hu, Zhaoyan; Lu, Lijun; Zhang, Tianyi; Chen, Zhenglong; Zhang, Tao

    2013-12-01

    This paper mainly studies the driving system of centrifugal blood pump for extracorporeal circulation, with the core being disc magnetic coupling. Structure parameters of disc magnetic coupling are related to the ability of transferring magnetic torque. Therefore, it is necessary to carry out disc magnetic coupling permanent magnet pole number (n), air gap length (L(g)), permanent magnet thickness (L(m)), permanent magnet body inside diameter (R(i)) and outside diameter (R(o)), etc. thoroughly. This paper adopts the three-dimensional static magnetic field edge element method of Ansys for numerical calculation, and analyses the relations of magnetic coupling each parameter to transmission magnetic torque. It provides a good theory basis and calculation method for further optimization of the disc magnetic coupling.

  5. Natural circulating passive cooling system for nuclear reactor containment structure

    DOEpatents

    Gou, Perng-Fei; Wade, Gentry E.

    1990-01-01

    A passive cooling system for the contaminant structure of a nuclear reactor plant providing protection against overpressure within the containment attributable to inadvertent leakage or rupture of the system components. The cooling system utilizes natural convection for transferring heat imbalances and enables the discharge of irradiation free thermal energy to the atmosphere for heat disposal from the system.

  6. Natural Convection and Boiling for Cooling SRP Reactors During Loss of Circulation Conditions

    SciTech Connect

    Buckner, M.R.

    2001-06-26

    This study investigated natural convection and boiling as a means of cooling SRP reactors in the event of a loss of circulation accident. These studies show that single phase natural convection cooling of SRP reactors in shutdown conditions with the present piping geometry is probably not feasible.

  7. System Analysis for Decay Heat Removal in Lead-Bismuth Cooled Natural Circulated Reactors

    SciTech Connect

    Takaaki Sakai; Yasuhiro Enuma; Takashi Iwasaki; Kazuhiro Ohyama

    2002-07-01

    Decay heat removal analyses for lead-bismuth cooled natural circulation reactors are described in this paper. A combined multi-dimensional plant dynamics code (MSG-COPD) has been developed to conduct the system analysis for the natural circulation reactors. For the preliminary study, transient analysis has been performed for a 100 MWe lead-bismuth-cooled reactor designed by Argonne National Laboratory (ANL). In addition, decay heat removal characteristics of a 400 MWe lead-bismuth-cooled natural circulation reactor designed by Japan Nuclear Cycle Development Institute (JNC) has been evaluated by using MSG-COPD. PRACS (Primary Reactor Auxiliary Cooling System) is prepared for the JNC's concept to get sufficient heat removal capacity. During 2000 sec after the transient, the outlet temperature shows increasing tendency up to the maximum temperature of 430 Centigrade, because the buoyancy force in a primary circulation path is temporary reduced. However, the natural circulation is recovered by the PRACS system and the out let temperature decreases successfully. (authors)

  8. System Analysis for Decay Heat Removal in Lead-Bismuth-Cooled Natural-Circulation Reactors

    SciTech Connect

    Sakai, Takaaki; Enuma, Yasuhiro; Iwasaki, Takashi

    2004-03-15

    Decay heat removal analyses for lead-bismuth-cooled natural-circulation reactors are described in this paper. A combined multidimensional plant dynamics code (MSG-COPD) has been developed to conduct the system analysis for the natural-circulation reactors. For the preliminary study, transient analysis has been performed for a 300-MW(thermal) lead-bismuth-cooled reactor designed by Argonne National Laboratory. In addition, decay heat removal characteristics of a 400-MW(electric) lead-bismuth-cooled natural-circulation reactor designed by the Japan Nuclear Cycle Development Institute (JNC) has been evaluated by using MSG-COPD. The primary reactor auxiliary cooling system (PRACS) is prepared for the JNC concept to get sufficient heat removal capacity. During 2000 s after the transient, the outlet temperature shows increasing tendency up to the maximum temperature of 430 deg. C because the buoyancy force in a primary circulation path is temporarily reduced. However, the natural circulation is recovered by the PRACS system, and the outlet temperature decreases successfully.

  9. On Stability of Natural-circulation-cooled Boiling Water Reactors during Start-up (Experimental Results)

    SciTech Connect

    Manera, A.; Van der Hagen, T.H.J.J.

    2002-07-01

    The characteristics of flashing-induced instabilities, which are of importance during the start-up phase of natural-circulation Boiling Water Reactors (BWRs), are studied. Experiments at typical start-up conditions (low power and low pressure) are carried out on a steam/water natural circulation loop. The mechanism of flashing-induced instability is analyzed in detail and it is found that non-equilibrium between phases and enthalpy transport plays an important role in the instability process. Pressure and steam volume in the steam dome are found to have a stabilizing effect. The main characteristics of the instabilities have been analyzed. (authors)

  10. COBRA-WC model and predictions for a fast-reactor natural-circulation transient. [LMFBR

    SciTech Connect

    George, T.L.; Basehore, K.L.; Prather, W.A.

    1980-01-01

    The COBRA-WC (Whole Core) code has been used to predict the core-wide coolant and rod temperature distribution in a liquid metal fast reactor during the early part (first 220 seconds) of a natural circulation transient. Approximately one-sixth of the core was modeled including bypass flows and the pressure losses above and below the core region. Detailed temperature and flow distributions were obtained for the two test fuel assemblies. The COBRA-WC model, the approach, and predictions of core-wide transient coolant and rod temperatures during a natural circulation transient are presented in this paper.

  11. Characterization of Circulating Natural Killer Cells in Neotropical Primates

    PubMed Central

    Carville, Angela; Evans, Tristan I.; Reeves, R. Keith

    2013-01-01

    Despite extensive use of nonhuman primates as models for infectious diseases and reproductive biology, imprecise phenotypic and functional definitions exist for natural killer (NK) cells. This deficit is particularly significant in the burgeoning use of small, less expensive New World primate species. Using polychromatic flow cytometry, we identified peripheral blood NK cells as CD3-negative and expressing a cluster of cell surface molecules characteristic of NK cells (i.e., NKG2A, NKp46, NKp30) in three New World primate species – common marmosets, cotton-top tamarins, and squirrel monkeys. We then assessed subset distribution using the classical NK markers, CD56 and CD16. In all species, similar to Old World primates, only a minor subset of NK cells was CD56+, and the dominant subset was CD56–CD16+. Interestingly, CD56+ NK cells were primarily cytokine-secreting cells, whereas CD56–CD16+ NK cells expressed significantly greater levels of intracellular perforin, suggesting these cells might have greater potential for cytotoxicity. New World primate species, like Old World primates, also had a minor CD56–CD16– NK cell subset that has no obvious counterpart in humans. Herein we present phenotypic profiles of New World primate NK cell subpopulations that are generally analogous to those found in humans. This conservation among species should support the further use of these species for biomedical research. PMID:24244365

  12. Self-sustained hydrodynamic oscillations in a natural-circulation two-phase-flow boiling loop

    NASA Technical Reports Server (NTRS)

    Jain, K. C.

    1969-01-01

    Results of an experimental and theoretical study of factors affecting self-sustaining hydrodynamic oscillations in boiling-water loops are reported. Data on flow variables, and the effects of geometry, subcooling and pressure on the development of oscillatory behavior in a natural-circulation two-phase-flow boiling loop are included.

  13. Distribution and budget of O3 in the troposphere calculated with a chemistry general circulation model

    NASA Astrophysics Data System (ADS)

    Roelofs, Geert-Jan; Lelieveld, Jos

    1995-10-01

    We present results of global tropospheric chemistry simulations with the coupled chemistry/atmospheric general circulation model ECHAM. Ultimately, the model will be used to study climate changes induced by anthropogenic influences on the chemistry of the atmosphere; meteorological parameters that are important for the chemistry, such as temperature, humidity, air motions, cloud and rain characteristics, and mixing processes are calculated on-line. The chemical part of the model describes background tropospheric CH4-CO-NOx-HOx photochemistry. Emissions of NO and CO, surface concentrations of CH4, and stratospheric concentrations of O3 and NOy are prescribed as boundary conditions. Calculations of the tropospheric O3 budget indicate that seasonal variabilities of the photochemical production and of injection from the stratosphere are represented realistically, although some aspects of the model still need improvement. Comparisons of calculated O3 surface concentrations and O3 profiles with available measurements show that the model reproduces O3 distributions in remote tropical and midlatitudinal sites. Also, the model matches typical profiles connected with deep convection in the Intertropical Convergence Zone (ITCZ). However, the model tends to underestimate O3 concentrations at the poles and in relatively polluted regions. These underestimates are caused by the poor representation of tropopause foldings in midlatitudes, which form a significant source of tropospheric O3 from the stratosphere, too weak transport to the poles, and the neglect of higher hydrocarbon chemistry. Also, mixing of polluted continental boundary layer air into the free troposphere may be underestimated. We discuss how these model deficiencies will be improved in the future.

  14. Navier-Stokes calculations and turbulence modeling in the trailing edge region of a circulation control airfoil

    NASA Technical Reports Server (NTRS)

    Viegas, John R.; Rubesin, Morris W.; Maccormack, Robert W.

    1987-01-01

    The accurate prediction of turbulent flows over curved surfaces in general and over the trailing edge region of circulation control airfoils in particular requires the coupled efforts of turbulence modelers, numerical analysts and experimentalists. The purpose of the research program in this area is described. Then, the influence on turbulence modeling of the flow characteristics over a typical circulation control wing is discussed. Next, the scope of this effort to study turbulence in the trailing edge region of a circulation control airfoil is presented. This is followed by a brief overview of the computation scheme, including the grid, governing equations, numerical method, boundary conditions and turbulence models applied to date. Then, examples of applications of two algebraic eddy viscosity models to the trailing edge region of a circulation control airfoil is presented. The results from the calculations is summarized, and conclusions drawn based on examples. Finally, the future directions of the program is outlined.

  15. Single and two-phase natural circulation in Westinghouse pressurized water reactor simulators: Phenomena, analysis and scaling

    SciTech Connect

    Schultz, R.R.; Chapman, J.C.; Kukita, Y.; Motley, F.E.; Stumpf, H.; Chen, Y.S.; Tasaka, K.

    1987-01-01

    Natural circulation data obtained in the 1/48 scale W four loop PWR simulator - the Large Scale Test Facility (LSTF) are discussed and summarized. Core cooling modes, the primary fluid state, the primary loop mass flow and localized natural circulation phenomena occurring in the steam generator are presented. TRAC-PF1 LSTF model (using both a 1 U-tube and a 3 U-tube steam generator model) analyses of the LSTF natural circulation data including the SG recirculation patterns are presented and compared to the data. The LSTF data are then compared to similar natural circulation data obtained in the Primarkreislaufe (PKL) and the Semiscale facilities. Based on the 1/48 to 1/1705 scaling range which exists between the facilities, the implications of these data towrard natural circulation behavior in commercial plants are briefly discussed.

  16. Evaluation Method for Core Thermohydraulics during Natural Circulation in Fast Reactors

    NASA Astrophysics Data System (ADS)

    Kamide, Hideki; Nagasawa, Kazuyoshi; Kimura, Nobuyuki; Miyakoshi, Hiroyuki

    Decay heat removal using natural circulation is one of significant functions for a reactor. As the decay heat removal system, a direct reactor auxiliary cooling system has been selected in current designs of fast reactors. In this system, cold sodium is provided in an upper plenum of reactor vessel and it covers the reactor core outlet. The cold sodium can penetrate into the gap region between the subassemblies. This gap flow is referred as inter-wrapper flow (IWF). A numerical estimation method for such phenomena was developed, which modeled each subassembly as a rectangular duct with gap region and also the upper plenum. This numerical simulation method was verified by a sodium test and also a water test. We applied this method to the natural circulation in a 600 MWe class fast reactor. The temperature in the core strongly depended on IWF, flow redistribution in the core, and inter-subassembly heat transfer.

  17. Enhancement of natural circulation type domestic solar hot water system performance by using a wind turbine

    NASA Astrophysics Data System (ADS)

    Ramasamy, K. K.; Srinivasan, P. S. S.

    2011-08-01

    Performance improvement of existing 200 litres capacity natural convection type domestic solar hot water system is attempted. A two-stage centrifugal pump driven by a vertical axis windmill having Savonius type rotor is added to the fluid loop. The windmill driven pump circulates the water through the collector. The system with necessary instrumentation is tested over a day. Tests on Natural Circulation System (NCS) mode and Wind Assisted System (WAS) mode are carried out during January, April, July and October, 2009. Test results of a clear day are reported. Daily average efficiency of 25-28 % during NCS mode and 33-37 % during WAS mode are obtained. With higher wind velocities, higher collector flow rates and hence higher efficiencies are obtained. In general, WAS mode provides improvements in efficiency when compared to NCS mode.

  18. An analytical and experimental investigation of natural circulation transients in a model pressurized water reactor

    SciTech Connect

    Massoud, M

    1987-01-01

    Natural Circulation phenomena in a simulated PWR was investigated experimentally and analytically. The experimental investigation included determination of system characteristics as well as system response to the imposed transient under symmetric and asymmetric operations. System characteristics were used to obtain correlation for heat transfer coefficient in heat exchangers, system flow resistance, and system buoyancy heat. Asymmetric transients were imposed to study flow oscillation and possible instability. The analytical investigation encompassed development of mathematical model for single-phase, steady-state and transient natural circulation as well as modification of existing model for two-phase flow analysis of phenomena such as small break LOCA, high pressure coolant injection and pump coast down. The developed mathematical model for single-phase analysis was computer coded to simulate the imposed transients. The computer program, entitled ''Symmetric and Asymmetric Analysis of Single-Phase Flow (SAS),'' were employed to simulate the imposed transients. It closely emulated the system behavior throughout the transient and subsequent steady-state. Modifications for two-phase flow analysis included addition of models for once-through steam generator and electric heater rods. Both programs are faster than real time. Off-line, they can be used for prediction and training applications while on-line they serve for simulation and signal validation. The programs can also be used to determine the sensitivity of natural circulation behavior to variation of inputs such as secondary distribution and power transients.

  19. Evaluation of circulating levels and renal clearance of natural amino acids in patients with Cushing's disease.

    PubMed

    Faggiano, A; Pivonello, R; Melis, D; Alfieri, R; Filippella, M; Spagnuolo, G; Salvatore, F; Lombardi, G; Colao, A

    2002-02-01

    Although the hypercortisolism-induced impairment of protein homeostasis is object of several studies, a detailed evaluation of the complete amino acid profile of patients with Cushing's syndrome (CS) has never been performed. The aim of the current open transversal controlled study was to evaluate serum and urinary concentrations as well as renal clearance of the complete series of natural amino acids and their relationship with glucose tolerance in patients with Cushing's disease (CD). Twenty patients with CD (10 active and 10 cured) and 20 sex- and age-matched healthy controls entered the study. Measurement of serum and urinary levels of the complete series of natural amino acids was performed in all patients analyzed by cationic exchange high performance liquid cromatography (HPLC) after 2 weeks of a standardized protein intake regimen. The renal clearance (renal excretion rate) of each amino acid was calculated on the basis of the serum and urinary concentrations of creatinine and the specific amino acid. Fasting glucose and insulin levels, glucose and insulin response to standard glucose load, insulinogenic and homeostasis model insulin resistance (Homa-R) indexes were also evaluated and correlated to the circulating levels and renal clearances of each amino acid. Significantly higher serum (p<0.01) and urinary (p<0.05) levels of alanine and cystine, lower serum and higher urinary levels of leucine, isoleucine and valine (p<0.05) and higher renal excretion rates of leucine, isoleucine and valine (p<0.01) were found in patients with active CD than in patients cured from the disease and in controls. No difference was found between cured patients and controls. Creatinine clearance was similar in active and cured patients and in controls. In patients with active CD, urinary cortisol levels were significantly correlated to urinary cystine levels (r=0.85; p<0.01) and renal excretion rate of leucine (r=-0.76; p<0.05), isoleucine (r=-0.76; p<0.05) and valine (r=-0

  20. Parametric study of natural circulation flow in molten salt fuel in molten salt reactor

    SciTech Connect

    Pauzi, Anas Muhamad; Cioncolini, Andrea; Iacovides, Hector

    2015-04-29

    The Molten Salt Reactor (MSR) is one of the most promising system proposed by Generation IV Forum (GIF) for future nuclear reactor systems. Advantages of the MSR are significantly larger compared to other reactor system, and is mainly achieved from its liquid nature of fuel and coolant. Further improvement to this system, which is a natural circulating molten fuel salt inside its tube in the reactor core is proposed, to achieve advantages of reducing and simplifying the MSR design proposed by GIF. Thermal hydraulic analysis on the proposed system was completed using a commercial computation fluid dynamics (CFD) software called FLUENT by ANSYS Inc. An understanding on theory behind this unique natural circulation flow inside the tube caused by fission heat generated in molten fuel salt and tube cooling was briefly introduced. Currently, no commercial CFD software could perfectly simulate natural circulation flow, hence, modeling this flow problem in FLUENT is introduced and analyzed to obtain best simulation results. Results obtained demonstrate the existence of periodical transient nature of flow problem, hence improvements in tube design is proposed based on the analysis on temperature and velocity profile. Results show that the proposed system could operate at up to 750MW core power, given that turbulence are enhanced throughout flow region, and precise molten fuel salt physical properties could be defined. At the request of the authors and the Proceedings Editor the name of the co-author Andrea Cioncolini was corrected from Andrea Coincolini. The same name correction was made in the Acknowledgement section on page 030004-10 and in reference number 4. The updated article was published on 11 May 2015.

  1. Parametric study of natural circulation flow in molten salt fuel in molten salt reactor

    NASA Astrophysics Data System (ADS)

    Pauzi, Anas Muhamad; Cioncolini, Andrea; Iacovides, Hector

    2015-04-01

    The Molten Salt Reactor (MSR) is one of the most promising system proposed by Generation IV Forum (GIF) for future nuclear reactor systems. Advantages of the MSR are significantly larger compared to other reactor system, and is mainly achieved from its liquid nature of fuel and coolant. Further improvement to this system, which is a natural circulating molten fuel salt inside its tube in the reactor core is proposed, to achieve advantages of reducing and simplifying the MSR design proposed by GIF. Thermal hydraulic analysis on the proposed system was completed using a commercial computation fluid dynamics (CFD) software called FLUENT by ANSYS Inc. An understanding on theory behind this unique natural circulation flow inside the tube caused by fission heat generated in molten fuel salt and tube cooling was briefly introduced. Currently, no commercial CFD software could perfectly simulate natural circulation flow, hence, modeling this flow problem in FLUENT is introduced and analyzed to obtain best simulation results. Results obtained demonstrate the existence of periodical transient nature of flow problem, hence improvements in tube design is proposed based on the analysis on temperature and velocity profile. Results show that the proposed system could operate at up to 750MW core power, given that turbulence are enhanced throughout flow region, and precise molten fuel salt physical properties could be defined. At the request of the authors and the Proceedings Editor the name of the co-author Andrea Cioncolini was corrected from Andrea Coincolini. The same name correction was made in the Acknowledgement section on page 030004-10 and in reference number 4. The updated article was published on 11 May 2015.

  2. Investigation of Natural Circulation Instability and Transients in Passively Safe Small Modular Reactors

    SciTech Connect

    Ishii, Mamoru

    2016-11-30

    The NEUP funded project, NEUP-3496, aims to experimentally investigate two-phase natural circulation flow instability that could occur in Small Modular Reactors (SMRs), especially for natural circulation SMRs. The objective has been achieved by systematically performing tests to study the general natural circulation instability characteristics and the natural circulation behavior under start-up or design basis accident conditions. Experimental data sets highlighting the effect of void reactivity feedback as well as the effect of power ramp-up rate and system pressure have been used to develop a comprehensive stability map. The safety analysis code, RELAP5, has been used to evaluate experimental results and models. Improvements to the constitutive relations for flashing have been made in order to develop a reliable analysis tool. This research has been focusing on two generic SMR designs, i.e. a small modular Simplified Boiling Water Reactor (SBWR) like design and a small integral Pressurized Water Reactor (PWR) like design. A BWR-type natural circulation test facility was firstly built based on the three-level scaling analysis of the Purdue Novel Modular Reactor (NMR) with an electric output of 50 MWe, namely NMR-50, which represents a BWR-type SMR with a significantly reduced reactor pressure vessel (RPV) height. The experimental facility was installed with various equipment to measure thermalhydraulic parameters such as pressure, temperature, mass flow rate and void fraction. Characterization tests were performed before the startup transient tests and quasi-steady tests to determine the loop flow resistance. The control system and data acquisition system were programmed with LabVIEW to realize the realtime control and data storage. The thermal-hydraulic and nuclear coupled startup transients were performed to investigate the flow instabilities at low pressure and low power conditions for NMR-50. Two different power ramps were chosen to study the effect of startup

  3. Two-phase flow stability structure in a natural circulation system

    SciTech Connect

    Zhou, Zhiwei

    1995-09-01

    The present study reports a numerical analysis of two-phase flow stability structures in a natural circulation system with two parallel, heated channels. The numerical model is derived, based on the Galerkin moving nodal method. This analysis is related to some design options applicable to integral heating reactors with a slightly-boiling operation mode, and is also of general interest to similar facilities. The options include: (1) Symmetric heating and throttling; (2) Asymmetric heating and symmetric throttling; (3) Asymmetric heating and throttling. The oscillation modes for these variants are discussed. Comparisons with the data from the INET two-phase flow stability experiment have qualitatively validated the present analysis.

  4. Natural triple excitations in local coupled cluster calculations with pair natural orbitals

    NASA Astrophysics Data System (ADS)

    Riplinger, Christoph; Sandhoefer, Barbara; Hansen, Andreas; Neese, Frank

    2013-10-01

    In this work, the extension of the previously developed domain based local pair-natural orbital (DLPNO) based singles- and doubles coupled cluster (DLPNO-CCSD) method to perturbatively include connected triple excitations is reported. The development is based on the concept of triples-natural orbitals that span the joint space of the three pair natural orbital (PNO) spaces of the three electron pairs that are involved in the calculation of a given triple-excitation contribution. The truncation error is very smooth and can be significantly reduced through extrapolation to the zero threshold. However, the extrapolation procedure does not improve relative energies. The overall computational effort of the method is asymptotically linear with the system size O(N). Actual linear scaling has been confirmed in test calculations on alkane chains. The accuracy of the DLPNO-CCSD(T) approximation relative to semicanonical CCSD(T0) is comparable to the previously developed DLPNO-CCSD method relative to canonical CCSD. Relative energies are predicted with an average error of approximately 0.5 kcal/mol for a challenging test set of medium sized organic molecules. The triples correction typically adds 30%-50% to the overall computation time. Thus, very large systems can be treated on the basis of the current implementation. In addition to the linear C150H302 (452 atoms, >8800 basis functions) we demonstrate the first CCSD(T) level calculation on an entire protein, Crambin with 644 atoms, and more than 6400 basis functions.

  5. Calculation of a residual mean meridional circulation for a zonal-mean tracer transport model

    SciTech Connect

    Choi, W.K.; Rotman, D.A.; Wuebbles, D.J.

    1995-04-01

    Because of their computational advantages, zonally-averaged chemical-radiative-transport models are widely used to investigate the distribution of chemical species and their change due to the anthropogenic chemicals in the lower and middle atmosphere. In general, the Lagrangian-mean formulation would be ideal to treat transport due to the zonal mean circulation and eddies. However, the Lagrangian formulation is difficult to use in practical applications. The most widely-used formulation for treating global atmospheric dynamics in two-dimensional models is the transformed Eulerian mean (TEM) equations. The residual mean meridional circulation (RMMC) in the TEM system is used to advect tracers. In this study, the authors describe possible solution techniques for obtaining the RMMC in the LLNL two-dimensional chemical-radiative-transport model. In the first section, the formulation will be described. In sections 3 and 4, possible solution procedures will be described for a diagnostic and prognostic case, respectively.

  6. Calculations of the time-averaged local heat transfer coefficients in circulating fluidized bed

    SciTech Connect

    Dai, T.H.; Qian, R.Z.; Ai, Y.F.

    1999-04-01

    The great potential to burn a wide variety of fuels and the reduced emission of pollutant gases mainly SO{sub x} and NO{sub x} have inspired the investigators to conduct research at a brisk pace all around the world on circulating fluidized bed (CFB) technology. An accurate understanding of heat transfer to bed walls is required for proper design of CFB boilers. To develop an optimum economic design of the boiler, it is also necessary to know how the heat transfer coefficient depends on different design and operating parameters. It is impossible to do the experiments under all operating conditions. Thus, the mathematical model prediction is a valuable method instead. Based on the cluster renewal theory of heat transfer in circulating fluidized beds, a mathematical model for predicting the time-averaged local bed-to-wall heat transfer coefficients is developed. The effects of the axial distribution of the bed density on the time-average local heat transfer coefficients are taken into account via dividing the bed into a series of sections along its height. The assumptions are made about the formation and falling process of clusters on the wall. The model predictions are in an acceptable agreement with the published data.

  7. The Venus nitric oxide night airglow - Model calculations based on the Venus Thermospheric General Circulation Model

    NASA Technical Reports Server (NTRS)

    Bougher, S. W.; Gerard, J. C.; Stewart, A. I. F.; Fesen, C. G.

    1990-01-01

    The mechanism responsible for the Venus nitric oxide (0,1) delta band nightglow observed in the Pioneer Venus Orbiter UV spectrometer (OUVS) images was investigated using the Venus Thermospheric General Circulation Model (Dickinson et al., 1984), modified to include simple odd nitrogen chemistry. Results obtained for the solar maximum conditions indicate that the recently revised dark-disk average NO intensity at 198.0 nm, based on statistically averaged OUVS measurements, can be reproduced with minor modifications in chemical rate coefficients. The results imply a nightside hemispheric downward N flux of (2.5-3) x 10 to the 9th/sq cm sec, corresponding to the dayside net production of N atoms needed for transport.

  8. [Physical and physiological principles of calculating vascular resistance in cardiovascular circulation].

    PubMed

    Hennig, E

    1992-01-01

    After reconstructive vascular surgery the quality of perfusion and the risk of failure can be predicted, if the distal outflow resistance of the graft is known. The laws of the hydrodynamics for the calculation of flow resistance in tubes are discussed with respect to their validity in the circulatory system. Because of great differences between the physiological realities and the physical assumption, and problems in monitoring some of the parameters of the equations, the calculation of the physiological vascular resistance according to the a.m. laws is not possible. With "Ohms law" of the hydrodynamic the calculation of the outflow resistance distal of a graft is possible if the flow through the bypass and the pressure losses in the outflow bed are known. Easier to perform is the measurement of the pressure-time integral generated by the injection of a standardized volume into the graft and the calculation of the outflow resistance with the help of a microprocessor.

  9. Natural circulation in a VVER reactor geometry: Experiments with the PACTEL facility and Cathare simulations

    SciTech Connect

    Raussi, P.; Kainulainen, S.; Kouhia, J.

    1995-09-01

    There are some 40 reactors based on the VVER design in use. Database available for computer code assessment for VVER reactors is rather limited. Experiments were conducted to study natural circulation behaviour in the PACTEL facility, a medium-scale integral test loop patterned after VVER pressurized water reactors. Flow behaviour over a range of coolant inventories was studied with a small-break experiment. In the small-break experiments, flow stagnation and system repressurization were observed when the water level in the upper plenum fell below the entrances to the hot legs. The cause was attributed to the hot leg loop seals, which are a unique feature of the VVER geometry. At low primary inventories, core cooling was achieved through the boiler-condenser mode. The experiment was simulated using French thermalhydraulic system code CATHARE.

  10. Modeling of thermohydraulic transients in a boiling helium natural circulation loop

    NASA Astrophysics Data System (ADS)

    Furci, H.; Baudouy, B.

    2016-12-01

    Boiling helium natural circulation loops are a cooling option for superconducting magnets. Previous studies on the field have provided a thorough understanding of their steady state behavior in all boiling regimes. Recent experimental research has lead to the understanding of their transient behavior. In particular, it highlights the impact of the thermohydraulic evolution of the circuit on the onset of transient boiling crisis, which represents a limitation of the cooling system. Hence, the need of modeling this aspect of these systems. In this work we present modeling options of two-phase helium loops departing from the homogeneous equilibrium two-phase flow model. Reasonable additional assumptions are introduced to obtain a simplified model and the effect of these assumptions is evaluated by comparison with the solution of the non-simplified equations system. These methods are compared to experimental data to analyze their success and limitations.

  11. Two-phase flow instability and dryout in parallel channels in natural circulation

    SciTech Connect

    Duffey, R.B.; Rohatgi, U.S.; Hughes, E.D.

    1993-06-01

    The unique feature of parallel channel flows is that the pressure drop or driving head for the flow is maintained constant across any given channel by the flow in all the others, or by having a large downcomer or bypass in a natural circulation loop. This boundary condition is common in all heat exchangers, reactor cores and boilers, it is well known that the two-phase flow in parallel channels can exhibit both so-called static and dynamic instability. This leads to the question of the separability of the flow and pressure drop boundary conditions in the study of stability and dryout. For the areas of practical interest, the flow can be considered as incompressible. The dynamic instability is characterized by density (kinematic) or continuity waves, and the static instability by inertial (pressure drop) or manometric escalations. The static has been considered to be the zero-frequency or lowest mode of the dynamic case. We briefly review the status of the existing literature on both parallel channel static and dynamic instability, and the latest developments in theory and experiment. The difference between the two derivations lies in the retention of the time-dependent terms in the conservation equations. The effects and impact of design options are also discussed. Since dryout in parallel systems follows instability, it has been traditional to determine the dryout power for a parallel channel by testing a single channel with a given (inlet) flow boundary condition without particular regard for the pressure drop. Thus all modern dryout correlations are based on constant or fixed flow tests, a so-called hard inlet, and subchannel and multiple bundle effects are corrected for separately. We review the thinking that lead to this approach, and suggest that for all multiple channel and natural circulation systems close attention should be paid to the actual (untested) pressure drop conditions. A conceptual formulation is suggested as a basis for discussion.

  12. Thermalhydraulic aspects of decay heat removal by natural circulation in fast reactor systems

    SciTech Connect

    Roy, C.M.; Hetsroni, G.; Banerjee, S.

    1990-01-01

    Natural convection in enclosures have been studied numerically to provide insight into the scaling laws existing for removal of decay heat in Liquid Metal Fast Reactors (LMFR). Specifically, 3-D simulations have been carried out for natural circulation in a cylinder with small aspect ratio (of the order of 0.5). These results have been compared to the results of an experiment conducted by UCSB, in collaboration with GE, to provide benchmark data for code validation. Parametric studies have been conducted to establish the validity of a 3-D Finite difference code that uses body-fitted grids for simulations of complex geometries. Further, numerical simulations have been carried out to demonstrate the importance of 3-D computer codes as tools in the design and scale-up of prototype LMFRs. It has been shown that the geometry of the passive safety systems is key to safe operation of LMFRs under shutdown conditions. The key phenomena that occur in such situations have bee studied and the available experimental studies have been identified. The future direction for modeling of natural convection recirculating flows in confined enclosures has been proposed. 31 refs.

  13. Thermalhydraulic aspects of decay heat removal by natural circulation in fast reactor systems. Final report

    SciTech Connect

    Roy, C.M.; Hetsroni, G.; Banerjee, S.

    1990-12-31

    Natural convection in enclosures have been studied numerically to provide insight into the scaling laws existing for removal of decay heat in Liquid Metal Fast Reactors (LMFR). Specifically, 3-D simulations have been carried out for natural circulation in a cylinder with small aspect ratio (of the order of 0.5). These results have been compared to the results of an experiment conducted by UCSB, in collaboration with GE, to provide benchmark data for code validation. Parametric studies have been conducted to establish the validity of a 3-D Finite difference code that uses body-fitted grids for simulations of complex geometries. Further, numerical simulations have been carried out to demonstrate the importance of 3-D computer codes as tools in the design and scale-up of prototype LMFRs. It has been shown that the geometry of the passive safety systems is key to safe operation of LMFRs under shutdown conditions. The key phenomena that occur in such situations have bee studied and the available experimental studies have been identified. The future direction for modeling of natural convection recirculating flows in confined enclosures has been proposed. 31 refs.

  14. Stability analysis of a natural circulation lead-cooled fast reactor

    NASA Astrophysics Data System (ADS)

    Lu, Qiyue

    This dissertation is aimed at nuclear-coupled thermal hydraulics stability analysis of a natural circulation lead cooled fast reactor design. The stability concerns arise from the fact that natural circulation operation makes the system susceptible to flow instabilities similar to those observed in boiling water reactors. In order to capture the regional effects, modal expansion method which incorporates higher azimuthal modes is used to model the neutronics part of the system. A reduced order model is used in this work for the thermal-hydraulics. Consistent with the number of heat exchangers (HXs), the reactor core is divided into four equal quadrants. Each quadrant has its corresponding external segments such as riser, plenum, pipes and HX forming an equivalent 1-D closed loop. The local pressure loss along the loop is represented by a lumped friction factor. The heat transfer process in the HX is represented by a model for the coolant temperature at the core inlet that depends on the coolant temperature at the core outlet and the coolant velocity. Additionally, time lag effects are incorporated into this HX model due to the finite coolant speed. A conventional model is used for the fuel pin heat conduction to couple the neutronics and thermal-hydraulics. The feedback mechanisms include Doppler, axial/radial thermal expansion and coolant density effects. These effects are represented by a linear variation of the macroscopic cross sections with the fuel temperature. The weighted residual method is used to convert the governing PDEs to ODEs. Retaining the first and second modes, leads to six ODEs for neutronics, and five ODEs for the thermal-hydraulics in each quadrant. Three models are developed. These are: 1) natural circulation model with a closed coolant flow path but without coupled neutronics, 2) forced circulation model with constant external pressure drop across the heated channels but without coupled neutronics, 3) coupled system including neutronics with

  15. A model of the circulating blood for use in radiation dose calculations

    SciTech Connect

    Hui, T.E.; Poston, J.W. Sr.

    1987-12-31

    Over the last few years there has been a significant increase in the use of radionuclides in leukocyte, platelet, and erythrocyte imaging procedures. Radiopharmaceutical used in these procedures are confined primarily to the blood, have short half-lives, and irradiate the body as they move through the circulatory system. There is a need for a model, to describe the circulatory system in an adult human, which can be used to provide radiation absorbed dose estimates for these procedures. A simplified model has been designed assuming a static circulatory system and including major organs of the body. The model has been incorporated into the MIRD phantom and calculations have been completed for a number of exposure situations and radionuclides of clinical importance. The model will be discussed in detail and results of calculations using this model will be presented.

  16. A model of the circulating blood for use in radiation dose calculations

    SciTech Connect

    Hui, T.E.; Poston, J.W. Sr.

    1987-01-01

    Over the last few years there has been a significant increase in the use of radionuclides in leukocyte, platelet, and erythrocyte imaging procedures. Radiopharmaceutical used in these procedures are confined primarily to the blood, have short half-lives, and irradiate the body as they move through the circulatory system. There is a need for a model, to describe the circulatory system in an adult human, which can be used to provide radiation absorbed dose estimates for these procedures. A simplified model has been designed assuming a static circulatory system and including major organs of the body. The model has been incorporated into the MIRD phantom and calculations have been completed for a number of exposure situations and radionuclides of clinical importance. The model will be discussed in detail and results of calculations using this model will be presented.

  17. The nature of chemical bonds from PNOF5 calculations.

    PubMed

    Matxain, Jon M; Piris, Mario; Uranga, Jon; Lopez, Xabier; Merino, Gabriel; Ugalde, Jesus M

    2012-06-18

    Natural orbital functional theory (NOFT) is used for the first time in the analysis of different types of chemical bonds. Concretely, the Piris natural orbital functional PNOF5 is used. It provides a localization scheme that yields an orbital picture which agrees very well with the empirical valence shell electron pair repulsion theory (VSEPR) and Bent's rule, as well as with other theoretical pictures provided by valence bond (VB) or linear combination of atomic orbitals-molecular orbital (LCAO-MO) methods. In this context, PNOF5 provides a novel tool for chemical bond analysis. In this work, PNOF5 is applied to selected molecules that have ionic, polar covalent, covalent, multiple (σ and π), 3c-2e, and 3c-4e bonds.

  18. Steam condensation and liquid hold-up in steam generator U-tubes during oscillatory natural circulation

    SciTech Connect

    De Santi, G.F.; Mayinger, F.

    1990-01-01

    In many accident scenarios, natural circulation is an important heat transport mechanism for long-term cooling of light water reactors. In the event of a small pipe break, with subsequent loss of primary cooling fluid loss-of-coolant accident (LOCA), or under abnormal operating conditions, early tripping of the main coolant pumps can be actuated. Primary fluid flow will then progress from forced to natural convection. Understanding of the flow regimes and heat-removal mechanisms in the steam generators during the entire transient is of primary importance to safety analysis. Flow oscillations during two-phase natural circulation experiments for pressurized water reactors (PWRs) with inverted U-tube steam generators occur at high pressure and at a primary inventory range between two-phase circulation and reflex heat removal. This paper deals with the oscillatory flow behavior that was observed in the LOBI-MOD2 facility during the transition period between two-phase natural circulation and reflex condensation.

  19. Calculation of fluid circulation patterns in the vicinity of submerged jets using ORSMAC

    NASA Astrophysics Data System (ADS)

    Park, J. E.; Cross, K. E.

    1980-01-01

    As the world demand for electricity is met by large coal or nuclear fueled central generating stations, the effluent streams from these plants will have an increasingly important impact on the local environment. The Nuclear Regulatory Commission has a responsibility to assess the impact of proposed and operating nuclear power plants. To support this NRC mission, a numerical algorithm and associated computer program were developed to predict the temperatures occurring in the immediate vicinity (the near field) of a hot water discharge from a power plant. The algorithm is a natural extension of the classic Marker-and-Cell (MAC) technique developed by F.H. Harlow at the Los Alamos Scientific Laboratory. ORSMAC adds the logic for simple turbulence modeling, energy conservation and buoyancy effects to the MAC model. Modern numerical techniques were used wherever practical. The MAC and SMAC (Simplified MAC) algorithms are reviewed, and the ORSMAC algorithm is described. The finite difference analogs are given and discussed. Solutions for several sample problems are presented which illustrate the features of the ORSMAC algorithm. A complete FORTRAN listing is included with input and sample output. Recommendations for further testing are included.

  20. [Impact of effect of natural disasters on the circulation of causative agents of parasitic diseases].

    PubMed

    Vaserin, Iu I; Khromenkova, E P; Dimidova, L L; Tverdokhlebova, T I; Nagornyĭ, S A; Prokopova, L V; Dumbadze, O S; Murashov, N E; Butaev, T M; Agirov, A Kh; Osmolovskiĭ, S V; Papatsenko, L B; Soldatova, M V

    2005-01-01

    The southern region is marked by a high incidence of parasitic diseases and a significant contamination of environmental objects with the eggs and cysts of their pathogens. Background examinations revealed the greatest soil contamination with helminthic eggs in the Temryuksky District of the Krasnodar Territory and in the towns of Vladikavkaz and Digora of the Republic of North Ossetia (Alania). The least contamination was found in Rostov-on-Don and the towns of the south-western area of the Krasnodar Territory. The eggs of Toxocara and astamination. There is an increase in the proportion of soil positive tests from 26.6 to 50.0, with the high (up to 82.0-100.0%) viability of eggs and a rise in the intensive index of their content per kg of soil (from 2.7 to 4.7-11.0). Toxocara eggs were mainly detected. The established high proportion of seropositive persons (10.7-18.0%) among the local population is an additional verification of the wide circulation of Toxocara eggs in nature. By the helminthic egg contamination index, the soils of localities of the south of Russia are qualified as those of moderate epidemic hazard. The floods accompanied by the increased helminthological contamination of the upper soil layer may lead to a higher human risk for contamination with helminthic diseases.

  1. Experiments in a single-phase natural circulation mini-loop

    SciTech Connect

    Misale, M.; Garibaldi, P.; Passos, J.C.; de Bitencourt, G. Ghisi

    2007-08-15

    This study reports an experimental investigation related to a rectangular single-phase natural circulation mini-loop, which consists of two horizontal copper tubes (heat transfer sections) and two vertical tubes (legs) made of copper, connected by means of four glass 90 bends. The loop inner diameter is 4 mm. The lower heating section consists of an electrical heating wire made of nicromel on the outside of the copper tube; the upper cooling system consists of a coaxial cylindrical heat exchanger with a water-glycol mixture, set at controlled temperature and flowing through the annulus. The loop has an imposed heat flux in the lower heating section and an imposed temperature in the cooler. The mini-loop was placed onto a table which can assume different inclinations. The parameters investigated during the experiments were: power transferred to the fluid and inclination of the loop. The preliminary results show a stable behaviour with a steady temperature difference across the heat sinks. It has been confirmed that the fluid velocity is very small (order of millimetres per second). (author)

  2. Chaotic Phenomena and Analysis of Natural Circulation Flow Instability under Rolling Motion Condition

    NASA Astrophysics Data System (ADS)

    Tan, S. C.; Gao, P. Z.

    2010-03-01

    Experimental study on natural circulation flow instability under rolling motion is carried out and the results show that the complex flow oscillations are formed due to the overlapped effect of the rolling motion (trough instability) and density wave oscillation. The system becomes more instable because of the occurrence of complex flow oscillations. Complex flow oscillations only occur in the case of high subcooling and may be divided into two types: regular and irregular complex flow oscillations. Under the same thermo hydraulic conditions, the marginal stability boundary (MSB) of regular complex oscillations is similar to that of density wave oscillation without rolling motion. And the influences of rolling amplitude and rolling period on its MSB are slight. Chaotic characteristics are found in irregular complex oscillation flow under rolling motion condition. Based on the experimental data and G-P method, correlation dimension and Kolmogorov entropy are gotten with time series analysis. The results show that complex oscillation has fractal dimension and positive Kolmogorov entropy and is typical chaotic time series.

  3. Preliminary numerical studies of an experimental facility for heat removal in natural circulation

    NASA Astrophysics Data System (ADS)

    Bertani, C.; De Salve, M.; Caramello, M.; Falcone, N.; Bersano, A.; Panella, B.

    2017-01-01

    In recent years particular attention has been dedicated to passive safety systems for heat removal in nuclear power plants. Passive safety systems can achieve a high level of safety, as they carry out their mission relying solely on physical principles like natural circulation, without any need of operators or energy sources. To qualify these systems and components experimental activities are necessary to study and to understand the governing physical phenomena. The present paper shows the design of an experimental facility to be installed in the laboratories of the Energy Department of Politecnico di Torino. The facility is inspired by the decay heat removal system for ALFRED reactor and comprehends a heated bayonet tube and a heat sink for the heat removal (a heat exchanger inside a pool). The thermal power is in the order of 1 kW. A RELAP5-3D model of the facility has been developed and sensitivity analyses were performed to highlight the geometry of the heat exchanger, the final heat sink, and the mass of water inside the loop. The results of this phase serve to understand the physical limits of the facility, to demonstrate a preliminary feasibility and to optimize the geometry for the desired operating conditions.

  4. Climatology and natural variability of the global hydrologic cycle in the GLA atmospheric general circulation model

    NASA Technical Reports Server (NTRS)

    Lau, K.-M.; Mehta, V. M.; Sud, Y. C.; Walker, G. K.

    1994-01-01

    Time average climatology and low-frequency variabilities of the global hydrologic cycle (GHC) in the Goddard Laboratory for Atmospheres (GLA) general circulation model (GCM) were investigated in the present work. A 730-day experiment was conducted with the GLA GCM forced by insolation, sea surface temperature, and ice-snow undergoing climatological annual cycles. Ifluences of interactive soil moisture on time average climatology and natural variability of the GHC were also investigated by conducting 365-day experiments with and without interactive soil moisture. Insolation, sea surface temperature, and ice-snow were fixed at their July levels in the latter two experiments. Results show that the model's time average hydrologic cycle variables for July in all three experiments agree reasonably well with observations. Except in the case of precipitable water, the zonal average climates of the annual cycle experiment and the two perpetual July experiments are alike, i.e., their differences are within limits of the natural variability of the model's climate. Statistics of various components of the GHC, i.e., water vapor, evaporation, and precipitation, are significantly affected by the presence of interactive soil moisture. A long-term trend is found in the principal empirical modes of variability of ground wetness, evaporation, and sensible heat. Dominant modes of variability of these quantities over land are physically consistent with one another and with land surface energy balance requirements. The dominant mode of precipitation variability is found to be closely related to organized convection over the tropical western Pacific Ocean. The precipitation variability has timescales in the range of 2 to 3 months and can be identified with the stationary component of the Madden-Julian Oscillation. The precipitation mode is not sensitive to the presence of interactive soil moisture but is closely linked to both the rotational and divergent components of atmospheric

  5. Thermohydraulic model experiments on the transition from forced to natural circulation for pool-type fast reactors

    SciTech Connect

    Hoffmann, H.; Marten, K.; Weinberg, D. )

    1992-09-01

    In this paper, thermohydraulic studies on the transition from forced to natural convection are carried out using the 1:20 scale RAMONA three-dimensional reactor model with water as the simulant fluid. In the investigations, a scram from 40% load operation of a fast reactor is simulated. The core mass flows and the core as well as the hot plenum temperatures are measured as a function of time for various core power levels, coastdown curves of the primary- and secondary-side pumps, and for various delay times for the start of the immersion coolers after a scram. These parameters influence the onset of the natural circulation in the reactor tank. The main result is that the longer the intermediate heat exchanger coolability is ensured and the later the immersion coolers start to operate, the higher is the natural-circulation flow and, hence, the lower are the core temperatures.

  6. Buoyancy Driven Coolant Mixing Studies of Natural Circulation Flows at the ROCOM Test Facility Using ANSYS CFX

    SciTech Connect

    Hohne, Thomas; Kliem, Soren; Rohde, Ulrich; Weiss, Frank-Peter

    2006-07-01

    Coolant mixing in the cold leg, downcomer and the lower plenum of pressurized water reactors is an important phenomenon mitigating the reactivity insertion into the core. Therefore, mixing of the de-borated slugs with the ambient coolant in the reactor pressure vessel was investigated at the four loop 1:5 scaled ROCOM mixing test facility. Thermal hydraulics analyses showed, that weakly borated condensate can accumulate in particular in the pump loop seal of those loops, which do not receive safety injection. After refilling of the primary circuit, natural circulation in the stagnant loops can re-establish simultaneously and the de-borated slugs are shifted towards the reactor pressure vessel (RPV). In the ROCOM experiments, the length of the flow ramp and the initial density difference between the slugs and the ambient coolant was varied. From the test matrix experiments with 0 resp. 2% density difference between the de-borated slugs and the ambient coolant were used to validate the CFD software ANSYS CFX. To model the effects of turbulence on the mean flow a higher order Reynolds stress turbulence model was employed and a mesh consisting of 6.4 million hybrid elements was utilized. Only the experiments and CFD calculations with modeled density differences show a stratification in the downcomer. Depending on the degree of density differences the less dense slugs flow around the core barrel at the top of the downcomer. At the opposite side the lower borated coolant is entrained by the colder safety injection water and transported to the core. The validation proves that ANSYS CFX is able to simulate appropriately the flow field and mixing effects of coolant with different densities. (authors)

  7. Pulsational characteristics of the natural-circulation loop of a large-scale model of a light-boiling boiling-water reactor

    SciTech Connect

    Babykin, A.S.; Balunov, B.F.; Chernykh, N.G.; Smirnov, E.L.; Tisheninova, V.I.; Zhiuitskaya, T.S.

    1985-10-01

    The results of an experimental study of a natural-circulation (NC) loop, whose geometrical and hydraulic characteristics are presented are described. The range of state parameters encompassed in the experiments is also indicated. The authors used a large-scale model of a low-boiling-water reactor, with natural heights and reduced stages of separate elements of the NC loop. The study confirmed that under the conditions the pulsations in the flow rate of the coolant occurs only in the transitional zone from natural circulation of the singlephase medium to natural circulation of the two-phase coolant.

  8. Design of Complex Systems to Achieve Passive Safety: Natural Circulation Cooling of Liquid Salt Pebble Bed Reactors

    NASA Astrophysics Data System (ADS)

    Scarlat, Raluca Olga

    This dissertation treats system design, modeling of transient system response, and characterization of individual phenomena and demonstrates a framework for integration of these three activities early in the design process of a complex engineered system. A system analysis framework for prioritization of experiments, modeling, and development of detailed design is proposed. Two fundamental topics in thermal-hydraulics are discussed, which illustrate the integration of modeling and experimentation with nuclear reactor design and safety analysis: thermal-hydraulic modeling of heat generating pebble bed cores, and scaled experiments for natural circulation heat removal with Boussinesq liquids. The case studies used in this dissertation are derived from the design and safety analysis of a pebble bed fluoride salt cooled high temperature nuclear reactor (PB-FHR), currently under development in the United States at the university and national laboratories level. In the context of the phenomena identification and ranking table (PIRT) methodology, new tools and approaches are proposed and demonstrated here, which are specifically relevant to technology in the early stages of development, and to analysis of passive safety features. A system decomposition approach is proposed. Definition of system functional requirements complements identification and compilation of the current knowledge base for the behavior of the system. Two new graphical tools are developed for ranking of phenomena importance: a phenomena ranking map, and a phenomena identification and ranking matrix (PIRM). The functional requirements established through this methodology were used for the design and optimization of the reactor core, and for the transient analysis and design of the passive natural circulation driven decay heat removal system for the PB-FHR. A numerical modeling approach for heat-generating porous media, with multi-dimensional fluid flow is presented. The application of this modeling

  9. Do general circulation models underestimate the natural variability in the artic climate?

    SciTech Connect

    Battisti, D.S.; Bitz, C.M.; Moritz, R.E.

    1997-08-01

    The authors examine the natural variability of the arctic climate system simulated by two very different models: the Geophysical Fluid Dynamics Laboratory (GFDL) global climate model, and an area-averaged model of the arctic atmosphere-sea ice-upper-ocean system called the polar cap climate model, the PCCM. A 1000-yr integration of the PCCM is performed in which the model is driven by a prescribed, stochastic atmospheric energy flux convergence (D), which has spectral characteristics that are identical to the spectra of the observed D. The standard deviation of the yearly mean sea ice thickness from this model is 0.85 m; the mean sea ice thickness is 3.1 m. In contrast, the standard deviation of the yearly averaged sea ice thickness in the GFDL climate model is found to be about 6% of the climatological mean thickness and only 24% of that simulated by the PCCM. A series of experiments is presented to determine the cause of these disparate results. First, after changing the treatment of sea ice and snow albedo in the (standard) PCCM model to be identical thermodynamically to that in the GFDL model, the PCCM is driven with D from the GFDL control integration to demonstrate that the PCCM model produces an arctic climate similar to that of the GFDL model. Integrations of the PCCM are then examined in which the different prescriptions of the sea ice treatment (GFDL vs standard PCCM) and D (GFDL vs observed) are permutated. The authors present calculations that indicate the variability in the sea ice thickness is extremely sensitive to the spectrum of the atmospheric energy flux convergence. A conservative best estimate for the amplitude of the natural variability in the arctic sea ice volume is presented.The results suggest that most of the global climate models that have been used to evaluate climate change may also have artificially quiescent variability in the Arctic. 24 refs., 6 figs., 3 tabs.

  10. Calculation of Post-Closure Natural Convection Heat and Mass Transfer in Yucca Mountain Drifts

    SciTech Connect

    S. Webb; M. Itamura

    2004-03-16

    Natural convection heat and mass transfer under post-closure conditions has been calculated for Yucca Mountain drifts using the computational fluid dynamics (CFD) code FLUENT. Calculations have been performed for 300, 1000, 3000, and 10,000 years after repository closure. Effective dispersion coefficients that can be used to calculate mass transfer in the drift have been evaluated as a function of time and boundary temperature tilt.

  11. Overall results of and lessons learned from the IAEA CRP on sodium natural circulation test performed during the Phenix end-of-life experiments

    SciTech Connect

    Monti, S.; Toti, A.; Tenchine, D.; Pialla, D.

    2012-07-01

    In 2007, the International Atomic Energy Agency (IAEA) launched the Coordinated Research Project (CRP) 'Control Rod Withdrawal and Sodium Natural Circulation Tests Performed during the Phenix End-of-Life Experiments'. The overall purpose of the CRP, performed within the framework of the IAEA programme in support of innovative fast reactor technology development and deployment, is to improve the Member States' analytical capabilities in the various fields of research and design of sodium-cooled fast reactors through data and codes verification and validation. In particular the CRP, taking advantage of the End-of-Life set of experiments performed before the final shut-down of the French prototype fast breeder power reactor Phenix, aims at improving fast reactor simulation methods and design capabilities in the field of temperature and power distribution evaluation, as well as of the analysis of sodium natural circulation phenomena. The paper presents the overall results of the CRP, including blind calculations and post-test and sensitivity analyses carried out by the CRP participants, as well as lessons learned and recommendations for further future implementations to resolve open issues. (authors)

  12. Experimental investigation on the flow instability behavior of a multi-channel boiling natural circulation loop at low-pressures

    SciTech Connect

    Jain, Vikas; Nayak, A.K.; Vijayan, P.K.; Saha, D.; Sinha, R.K.

    2010-09-15

    Natural circulation as a mode of heat removal is being considered as a prominent passive feature in the innovative nuclear reactor designs, particularly in boiling-water-reactors, due to its simplicity and economy. However, boiling natural circulation system poses many challenges to designer due to occurrence of various kinds of instabilities such as excursive instability, density wave oscillations, flow pattern transition instability, geysering and metastable states in parallel channels. This problem assumes greater significance particularly at low-pressures i.e. during startup, where there is great difference in the properties of two phases. In light of this, a parallel channel loop has been designed and installed that has a geometrical resemblance to the pressure-tube-type boiling-water-reactor, to investigate into the behavior of boiling natural circulation. The loop comprises of four identical parallel channels connected between two common plenums i.e. steam drum and header. The recirculation path is provided by a single downcomer connected between steam drum and header. Experiments have been conducted over a wide range of power and pressures (1-10 bar). Two distinct unstable zones are observed with respect to power i.e. corresponding to low power (Type-I) and high power (Type-II) with a stable zone at intermediate powers. The nature of oscillations in terms of their amplitude and frequency and their evolution for Type-I and Type-II instabilities are studied with respect to the effect of heater power and pressure. This paper discusses the evolution of unstable and stable behavior along with the nature of flow oscillation in the channels and the effect of pressure on it. (author)

  13. Antimicrobial activity of various immunomodulators: independence from normal levels of circulating monocytes and natural killer cells. Technical report

    SciTech Connect

    Morahan, P.S.; Dempsey, W.L.; Volkman, A.; Connor, J.

    1986-01-01

    The effects of /sup 89/Sr treatment on the natural host resistance of CD-1 mice and the enhancement of resistance by immunomodulators to infection with Listeria monocytogenes or herpes simplex virus type 2 (HSV-2) were determined. In the CD-1 mouse, single-dose treatment with /sup 89/Sr caused a profound decrease in the number of circulating monocytes (Mo), lymphocytes, and polymorphonuclear leukocytes (PMN) within 1 week. There was also marked functional impairment of the Mo inflammatory response, as well as markedly decreased spontaneous and activatable cytoxicity by splenic natural killer (NK) cells. Despite this profound cellular suppression, there was no significant change in natural resistance of CD-1 mice to L. monocytogenes of HSV-2 infection. Furthermore, prophylactic treatment of mice with the biologic immunomodulator Corynebacterium parvum or the synthetic immunomodulators maleic anhydride-divinyl ether or avridine in liposomes resulted in comparable enhancement of resistance in /sup 89/Sr-treated and normal mice. These data indicate that natural and immunomodulator-enhanced resistance of CD-1 mice to microbail infections do not depend on normal levels of Mo, PMN, or NK cells. The resistance enhancement may rely on activated tissue macrophages. In contrast to the early changes in circulating leukocytes, the residenet peritoneal cell populations were not markedly altered until after day 30. There then was a distinct decline in lymphocytes and a gradual decline in activated tissue macrophages.

  14. The Essential Role of Circulating Thyroglobulin in Maintaining Dominance of Natural Regulatory T Cell Function to Prevent Autoimmune Thyroiditis.

    PubMed

    Kong, Y M; Brown, N K; Morris, G P; Flynn, J C

    2015-09-01

    Several key findings from the late 1960s to mid-1970s regarding thyroid hormone metabolism and circulating thyroglobulin composition converged with studies pertaining to the role of T lymphocytes in autoimmune thyroiditis. These studies cemented the foundation for subsequent investigations into the existence and antigenic specificity of thymus-derived natural regulatory T cells (nTregs). These nTregs prevented the development of autoimmune thyroiditis, despite the ever-present genetic predisposition, autoantigen (thyroglobulin), and thyroglobulin-reactive T cells. Guided by the hypothalamus-pituitary-thyroid axis as a fixed set-point regulator in thyroid hormone metabolism, we used a murine model and compared at key junctures the capacity of circulating thyroglobulin level (raised by thyroid-stimulating hormone or exogenous thyroglobulin administration) to strengthen self-tolerance and resist autoimmune thyroiditis. The findings clearly demonstrated an essential role for raised circulating thyroglobulin levels in maintaining the dominance of nTreg function and inhibiting thyroid autoimmunity. Subsequent identification of thyroglobulin-specific nTregs as CD4(+)CD25(+)Foxp3(+) in the early 2000s enabled the examination of probable mechanisms of nTreg function. We observed that whenever nTreg function was perturbed by immunotherapeutic measures, opportunistic autoimmune disorders invariably surfaced. This review highlights the step-wise progression of applying insights from endocrinologic and immunologic studies to advance our understanding of the clonal balance between natural regulatory and autoreactive T cells. Moreover, we focus on how tilting the balance in favor of maintaining peripheral tolerance could be achieved. Thus, murine autoimmune thyroiditis has served as a unique model capable of closely simulating natural physiologic conditions.

  15. Circulating natural killer and gammadelta T cells decrease soon after infection of rhesus macaques with lymphocytic choriomeningitis virus.

    PubMed

    Rodas, Juan D; Cairo, Cristiana; Djavani, Mahmoud; Zapata, Juan Carlos; Ruckwardt, Tracy; Bryant, Joseph; Pauza, C David; Lukashevich, Igor S; Salvato, Maria S

    2009-07-01

    Rhesus macaques infected with the WE strain of lymphocytic choriomeningitis virus (LCMV-WE) serve as a model for human infection with Lassa fever virus. To identify the earliest events of acute infection, rhesus macaques were monitored immediately after lethal infection for changes in peripheral blood mononuclear cells (PBMCs). Changes in CD3, CD4, CD8 and CD20 subsets did not vary outside the normal fluctuations of these blood cell populations; however, natural killer (NK) and gammadelta T cells increased slightly on day 1 and then decreased significantly after two days. The NK subsets responsible for the decrease were primarily CD3-CD8+ or CD3-CD16+ and not the NKT (primarily CD3+CD56+) subset. Macaques infected with a non-virulent arenavirus, LCMV-Armstrong, showed a similar drop in circulating NK and gammadelta T cells, indicating that this is not a pathogenic event. V(3)9 T cells, representing the majority of circulating gammadelta T cells in rhesus macaques, displayed significant apoptosis when incubated with LCMV in cell culture; however, the low amount of cell death for virus-co-cultured NK cells was insufficient to account for the observed disappearance of this subset. Our observations in primates are similar to those seen in LCMV-infected mice, where decreased circulating NK cells were attributed to margination and cell death. Thus, the disappearance of these cells during acute hemorrhagic fever in rhesus macaques may be a cytokine-induced lymphopenia common to many virus infections.

  16. Important factors stabilizing stacking interaction between 3-nitropyrrole and natural nucleobases revealed by ab initio calculations.

    PubMed

    Seio, Kohji; Ukawa, Hisashi; Shohda, Koh-ichiro; Sekine, Mitsuo

    2003-01-01

    Stacking energies between canonical nucleobases and a universal base, 3-nitropyrrole (3-NP), were estimated by use of molecular orbital (MO) and molecular mechanics (MM) calculations. The detailed analysis of the energy profiles revealed the importance of the London dispersion energy to stabilize the stacked dimers and electrostatic interactions to determine the orientation of 3-NP to the nucleobases in the dimers. Although the energy profiles of 3-NP/natural base dimers obtained by the MO and MM calculations were qualitatively correlated with each other, the correlations were poorer than those obtained for the stacking between natural bases. The origin of the difference between 3-NP and natural bases will be discussed to understand the possibility and limitation of the current MM calculations for the simulation and design of other universal bases.

  17. Natural variability of the climate as predicted by a simple ocean model with parameterized thermohaline circulation

    SciTech Connect

    Watts, R.G.; Li, S.

    1995-12-31

    Variability of the Earth`s climate can take place on many time scales as a result of internal features. This natural variability is important to humans since it affects such important human enterprises as agriculture, floods, droughts, etc. The authors investigate natural variability within a simple ocean model.

  18. Determination of absolute configuration of natural products: theoretical calculation of electronic circular dichroism as a tool

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Determination of absolute configuration (AC) is one of the most challenging features in the structure elucidation of chiral natural products, especially those with complex structures. With revolutionary advancements in the area of quantum chemical calculations of chiroptical spectroscopy over the pa...

  19. Calculation of a residual mean meridional circulation for a zonal-mean tracer transport model: Revision 1

    SciTech Connect

    Choi, W.K.; Rotman, D.A.; Wuebbles, D.J.

    1995-01-01

    Because of their computational advantages, zonally-averaged chemical-radiative-transport models are widely used to investigate the distribution of chemical species and their change due to the anthropogenic chemicals in the lower and middle atmosphere. In general, the Lagrangian-mean formulation would be ideal to treat transport due to the zonal mean circulation and eddies. However, the Lagrangian formulation is difficult to use in practical applications. The most widely-used formulation for treating global atmospheric dynamics in two-dimensional models is the transformed Eulerian mean (TEM) equations. The residual mean meridional circulation (RMMC) in the TEM system is used to advect tracers. In this study, we describe possible solution techniques for obtaining the RMMC in the LLNL two-dimensional chemical-radiative-transport model. In the next section, the formulation will be described. In sections 3 and 4, possible solution procedures will be described for a diagnostic and prognostic case, respectively.

  20. A new method of calculating electrical conductivity with applications to natural waters

    USGS Publications Warehouse

    McCleskey, R. Blaine; Nordstrom, D. Kirk; Ryan, Joseph N.; Ball, James W.

    2012-01-01

    A new method is presented for calculating the electrical conductivity of natural waters that is accurate over a large range of effective ionic strength (0.0004–0.7 mol kg-1), temperature (0–95 °C), pH (1–10), and conductivity (30–70,000 μS cm-1). The method incorporates a reliable set of equations to calculate the ionic molal conductivities of cations and anions (H+, Li+, Na+, K+, Cs+, NH4+, Mg2+, Ca2+, Sr2+, Ba2+, F-, Cl-, Br-, SO42-, HCO3-, CO32-, NO3-, and OH-), environmentally important trace metals (Al3+, Cu2+, Fe2+, Fe3+, Mn2+, and Zn2+), and ion pairs (HSO4-, NaSO4-, NaCO3-, and KSO4-). These equations are based on new electrical conductivity measurements for electrolytes found in a wide range of natural waters. In addition, the method is coupled to a geochemical speciation model that is used to calculate the speciated concentrations required for accurate conductivity calculations. The method was thoroughly tested by calculating the conductivities of 1593 natural water samples and the mean difference between the calculated and measured conductivities was -0.7 ± 5%. Many of the samples tested were selected to determine the limits of the method and include acid mine waters, geothermal waters, seawater, dilute mountain waters, and river water impacted by municipal waste water. Transport numbers were calculated and H+, Na+, Ca2+, Mg2+, NH4+, K+, Cl-, SO42-, HCO3-, CO32-, F-, Al3+, Fe2+, NO3-, and HSO4- substantially contributed (>10%) to the conductivity of at least one of the samples. Conductivity imbalance in conjunction with charge imbalance can be used to identify whether a cation or an anion measurement is likely in error, thereby providing an additional quality assurance/quality control constraint on water analyses.

  1. A new method of calculating electrical conductivity with applications to natural waters

    NASA Astrophysics Data System (ADS)

    McCleskey, R. Blaine; Nordstrom, D. Kirk; Ryan, Joseph N.; Ball, James W.

    2012-01-01

    A new method is presented for calculating the electrical conductivity of natural waters that is accurate over a large range of effective ionic strength (0.0004-0.7 mol kg-1), temperature (0-95 °C), pH (1-10), and conductivity (30-70,000 μS cm-1). The method incorporates a reliable set of equations to calculate the ionic molal conductivities of cations and anions (H+, Li+, Na+, K+, Cs+, NH4+, Mg2+, Ca2+, Sr2+, Ba2+, F-, Cl-, Br-, SO42-, HCO3-, CO32-, NO3-, and OH-), environmentally important trace metals (Al3+, Cu2+, Fe2+, Fe3+, Mn2+, and Zn2+), and ion pairs (HSO4-, NaSO4-, NaCO3-, and KSO4-). These equations are based on new electrical conductivity measurements for electrolytes found in a wide range of natural waters. In addition, the method is coupled to a geochemical speciation model that is used to calculate the speciated concentrations required for accurate conductivity calculations. The method was thoroughly tested by calculating the conductivities of 1593 natural water samples and the mean difference between the calculated and measured conductivities was -0.7 ± 5%. Many of the samples tested were selected to determine the limits of the method and include acid mine waters, geothermal waters, seawater, dilute mountain waters, and river water impacted by municipal waste water. Transport numbers were calculated and H+, Na+, Ca2+, Mg2+, NH4+, K+, Cl-, SO42-, HCO3-, CO32-, F-, Al3+, Fe2+, NO3-, and HSO4-substantially contributed (>10%) to the conductivity of at least one of the samples. Conductivity imbalance in conjunction with charge imbalance can be used to identify whether a cation or an anion measurement is likely in error, thereby providing an additional quality assurance/quality control constraint on water analyses.

  2. The global distribution of natural tritium in precipitation simulated with an Atmospheric General Circulation Model and comparison with observations

    NASA Astrophysics Data System (ADS)

    Cauquoin, A.; Jean-Baptiste, P.; Risi, C.; Fourré, É.; Stenni, B.; Landais, A.

    2015-10-01

    The description of the hydrological cycle in Atmospheric General Circulation Models (GCMs) can be validated using water isotopes as tracers. Many GCMs now simulate the movement of the stable isotopes of water, but here we present the first GCM simulations modelling the content of natural tritium in water. These simulations were obtained using a version of the LMDZ General Circulation Model enhanced by water isotopes diagnostics, LMDZ-iso. To avoid tritium generated by nuclear bomb testing, the simulations have been evaluated against a compilation of published tritium datasets dating from before 1950, or measured recently. LMDZ-iso correctly captures the observed tritium enrichment in precipitation as oceanic air moves inland (the so-called continental effect) and the observed north-south variations due to the latitudinal dependency of the cosmogenic tritium production rate. The seasonal variability, linked to the stratospheric intrusions of air masses with higher tritium content into the troposphere, is correctly reproduced for Antarctica with a maximum in winter. LMDZ-iso reproduces the spring maximum of tritium over Europe, but underestimates it and produces a peak in winter that is not apparent in the data. This implementation of tritium in a GCM promises to provide a better constraint on: (1) the intrusions and transport of air masses from the stratosphere, and (2) the dynamics of the modelled water cycle. The method complements the existing approach of using stable water isotopes.

  3. Natural circulation decay heat removal from an SP-100, 550 kWe power system for a lunar outpost

    NASA Technical Reports Server (NTRS)

    El-Genk, Mohamed S.; Xue, Huimin

    1992-01-01

    This research investigated the decay heat removal from the SP-100 reactor core of a 550-kWe power system for a lunar outpost by natural circulation of lithium coolant. A transient model that simulates the decay heat removal loop (DHRL) of the power system was developed and used to assess the system's decay heat removal capability. The effects of the surface area of the decay heat rejection radiator, the dimensions of the decay heat exchanger (DHE) flow duct, the elevation of the DHE, and the diameter of the rise and down pipes in the DHRL on the decay heat removal capability were examined. Also, to determine the applicability of test results at earth gravity to actual system performance on the lunar surface, the effect of the gravity constant (1 g and 1/6 g) on the thermal behavior of the system after shutdown was investigated.

  4. Steady state boiling crisis in a helium vertically heated natural circulation loop - Part 2: Friction pressure drop lessening

    NASA Astrophysics Data System (ADS)

    Furci, H.; Baudouy, B.; Four, A.; Meuris, C.

    2016-01-01

    Experiments were conducted on a 2-m high two-phase helium natural circulation loop operating at 4.2 K and 1 atm. Two heated sections with different internal diameter (10 and 6 mm) were tested. The power applied on the heated section wall was controlled in increasing and decreasing sequences, and temperature along the section, mass flow rate and pressure drop evolutions were registered. The post-CHF regime was studied watching simultaneously the evolution of boiling crisis onset along the test section and the evolution of pressure drop and mass flow rate. A significant lessening of friction was observed simultaneous to the development of the post-CHF regime, accompanied by a mass flow rate increase, which lets suppose that the vapor film in the film boiling regime acts as a lubricant. A model was created based on this idea and on heat transfer considerations. The predictions by this model are satisfactory for the low quality post-CHF regime.

  5. Low Circulating Natural Killer Cell Counts are Associated With Severe Disease in Patients With Common Variable Immunodeficiency

    PubMed Central

    Ebbo, Mikael; Gérard, Laurence; Carpentier, Sabrina; Vély, Frédéric; Cypowyj, Sophie; Farnarier, Catherine; Vince, Nicolas; Malphettes, Marion; Fieschi, Claire; Oksenhendler, Eric; Schleinitz, Nicolas; Vivier, Eric

    2016-01-01

    Natural Killer (NK) cells have been shown to exert antiviral and antitumoural activities. Nevertheless most available data are derived from mouse models and functions of these cells in human remain unclear. To evaluate the impact of low circulating NK cell counts and to provide some clues to the role of NK cells in natural conditions, we studied a large cohort of patients with common variable immunodeficiency (CVID) included in a multicenter cohort of patients with primary hypogammaglobulinaemia. Patients were classified into three groups on the basis of their NK cell counts: severe and mild NK cell lymphopenia (< 50 and 50–99 × 106/L respectively), and normal NK cell counts (> 100 × 106/L). Clinical events were analyzed and compared between these three groups of patients. During study period, 457 CVID patients were included: 99 (21.7%) with severe NK cell lymphopenia, 118 (25.8%) with mild NK cell lymphopenia and 240 (52.5%) with normal NK cell counts. Non-infectious complications (57% vs. 36% and 35%), and, particularly, granulomatous complications (25.3% vs. 13.6% and 8.8%), were more frequent in patients with severe NK cell lymphopenia than in other groups. Invasive infections (68.7% vs. 60.2% and 48.8%), including bacteraemia (22.2% vs. 5.9% and 8.3%) and infectious pneumonia (63.6% vs. 59.3% and 44.2%), were also more frequent in this population. However, no difference was observed for viral infections and neoplasms. Low circulating NK cell counts are associated with more severe phenotypes of CVID, which may indicate a protective role of these immune cells against severe bacterial infections and other complications and non-redundant immune functions when the adaptive immune response is not optimal. PMID:27211564

  6. Investigations on natural circulation in reactor models and shutdown heat removal systems for LMFBRs (liquid metal fast breeder reactors)

    SciTech Connect

    Hoffmann, H.; Weinberg, D.; Marten, K. ); Ieda, Yoshiaki )

    1989-11-01

    For sodium-cooled pool-type reactors, studies have been undertaken to remove the decay heat by natural convection alone, as in the case of failure of all power supplies. For this purpose, four immersion coolers (ICs), two each installed at a 180-deg circumferential position with respect to the others, are arranged within the reactor tank. They are connected with natural-drift air coolers through independent intermediate circuits. The primary sodium in the tank as well as the secondary sodium in the intermediate loop circulate by natural convection. The general functioning of this passive shutdown decay heat removal (DHR) system is demonstrated in 1:20 and 1:5 scale test models using water as a simulant fluid for sodium. The model design is based on the thermohydraulics similarity criteria. In the RAMONA three-dimensional 1:20 scale model, experiments were carried out to clarify the steady-state in-vessel thermohydraulics for different parameter combinations (core power, radial power distribution across the core, DHR by 2 or 4 ICs in operation, above-core structure geometry and position, different IC designs). For all mentioned parameters, temperatures and their fluctuations were measured and used to indicate isotherms and lines of identical temperature fluctuations. The flow patterns were observed visually. The experiments were recalculated by an updated version of the single-phase three-dimensional thermohydraulics code COMMIX.

  7. Natural Variability during Snowfall: Observations of Snowflake Microstructure and Calculations of Corresponding Snowfall Scattering Properties

    NASA Astrophysics Data System (ADS)

    Gergely, M.; Garrett, T. J.

    2015-12-01

    Significant progress has been achieved in approximating snowflakes and ice-cloud particles by increasingly more realistic and detailed shape models and in calculating associated scattering properties crucial to snowfall remote sensing. The applied approximations of the snowflake microstructure applied for the scattering calculations, however, are still based on few available field measurement data, often integrated over many individual snow storms, and only include several microstructural properties that cannot fully capture the natural variability during snowfall, e.g. different degrees of riming or aggregate snowflakes formed from more than one distinct ice crystal habit. In this study, (i) the natural variability of key microstructural properties during snowfall is quantified for individual snow storms based on high-resolution multi-view snowflake imaging data collected with the Multi-Angle Snowflake Camera (MASC) at Alta ski area (Alta, UT), and (ii) the corresponding variability in snowflake scattering properties is calculated. In addition to snowflake size, orientation and aspect ratio, 'particle complexity' (specifying snowflake perimeter and brightness variations in the MASC snowflake images) is included in the presented approach, yielding a quantitative and objective measure of characteristic snowflake microstructure, including crystal habit and degree of riming, important for realistically modelling snowfall scattering properties. The aim is to present an analysis of the impact of the observed natural microstructural variability on the derived snowflake scattering properties and ultimately on the snowfall radar reflectivity integrated over the obtained variability of snowflake microstructure and scattering properties.

  8. Natural Circulation in Water Cooled Nuclear Power Plants Phenomena, models, and methodology for system reliability assessments

    SciTech Connect

    Jose Reyes

    2005-02-14

    In recent years it has been recognized that the application of passive safety systems (i.e., those whose operation takes advantage of natural forces such as convection and gravity), can contribute to simplification and potentially to improved economics of new nuclear power plant designs. In 1991 the IAEA Conference on ''The Safety of Nuclear Power: Strategy for the Future'' noted that for new plants the use of passive safety features is a desirable method of achieving simplification and increasing the reliability of the performance of essential safety functions, and should be used wherever appropriate''.

  9. Walking in the woods with quantum chemistry--applications of quantum chemical calculations in natural products research.

    PubMed

    Tantillo, Dean J

    2013-08-01

    This Highlight describes applications of quantum chemical calculations to problems in natural products chemistry, including the elucidation of natural product structures (distinguishing between constitutional isomers, distinguishing between diastereomers, and assigning absolute configuration) and determination of reasonable mechanisms for their formation.

  10. Algorithms for calculating the dynamics of biocapacity and ecological footprint for natural and artificial ecosystems

    NASA Astrophysics Data System (ADS)

    Shuvaev, Andrey; Pechurkin, Nickolay

    Calculations of the dynamics of biological capacity (BC) and the ecological footprint (EF) is necessary to quantify the predictions and options to both natural and artificial ecosystems at different levels of the hierarchy. The magnitude of the BC as characteristic of the potential possibilities of the system is determined according to the integrated monitoring of physiological state, or photosynthetic activity, "green area" of the ecosystem. The quantity of the EF is defined as the amount required in the functioning of the system, including the production of the required products and degradation disposal unit. In our study we consider an example of the algorithm for calculating the dynamics of BC and EF for the quantification of the Krasnoyarsk Territory loaded as the natural ecosystem. The main burden was determined by EF, non-utilized emissions of carbon dioxide in the operation of energy businesses in the region. To verify the relevant calculations for BC processed data to ground and space monitor vegetation core areas of the province. In particular, the net primary production is calculated on the basis of the relative normalized vegetation index - NDVI (Normalized Difference Vegetation Index) based on satellite data A comparative evaluation of the contribution of each of the ways to generate energy (thermal and hydro ) in environmental load was made. A comparison of natural ecosystems and loaded specially created life-support systems in space and on the dynamics of BC/EF gives perspective to quantify the predictions and options for development of systems of different levels of the hierarchy. This work was supported by the Russian Foundation for Basic Research, project number 13-06-00060.

  11. The enrichment of natural radionuclides in oil shale-fired power plants in Estonia--the impact of new circulating fluidized bed technology.

    PubMed

    Vaasma, Taavi; Kiisk, Madis; Meriste, Tõnis; Tkaczyk, Alan Henry

    2014-03-01

    Burning oil shale to produce electricity has a dominant position in Estonia's energy sector. Around 90% of the overall electric energy production originates from the Narva Power Plants. The technology in use has been significantly renovated - two older types of pulverized fuel burning (PF) energy production units were replaced with new circulating fluidized bed (CFB) technology. Additional filter systems have been added to PF boilers to reduce emissions. Oil shale contains various amounts of natural radionuclides. These radionuclides concentrate and become enriched in different boiler ash fractions. More volatile isotopes will be partially emitted to the atmosphere via flue gases and fly ash. To our knowledge, there has been no previous study for CFB boiler systems on natural radionuclide enrichment and their atmospheric emissions. Ash samples were collected from Eesti Power Plant's CFB boiler. These samples were processed and analyzed with gamma spectrometry. Activity concentrations (Bq/kg) and enrichment factors were calculated for the (238)U ((238)U, (226)Ra, (210)Pb) and (232)Th ((232)Th, (228)Ra) family radionuclides and for (40)K in different CFB boiler ash fractions. Results from the CFB boiler ash sample analysis showed an increase in the activity concentrations and enrichment factors (up to 4.5) from the furnace toward the electrostatic precipitator block. The volatile radionuclide ((210)Pb and (40)K) activity concentrations in CFB boilers were evenly distributed in finer ash fractions. Activity balance calculations showed discrepancies between input (via oil shale) and output (via ash fractions) activities for some radionuclides ((238)U, (226)Ra, (210)Pb). This refers to a situation where the missing part of the activity (around 20% for these radionuclides) is emitted to the atmosphere. Also different behavior patterns were detected for the two Ra isotopes, (226)Ra and (228)Ra. A part of (226)Ra input activity, unlike (228)Ra, was undetectable in the

  12. CO2 adsorption and separation from natural gason phosphorene surface: Combining DFT and GCMC calculations

    NASA Astrophysics Data System (ADS)

    Zhang, Yayun; Liu, Chao; Hao, Feng; Xiao, Hang; Zhang, Shiwei; Chen, Xi

    2017-03-01

    We have examined the performance of phosphorene-based material, phosphorene slit pores (PSP), in CO2 adsorption and separation from natural gas by using Density Function Theory (DFT) calculation and Grand Canonical Monte Carlo (GCMC) simulations. First, the adsorption of CH4 and CO2molecules on phosphorene sheet were conducted by DFT study. Then, adsorption performances of natural gas components as well as their binary CO2/CH4 gas mixture were investigated at 300 K with the pressure up to 3.0 MPa. The effects of slit pore width, H, and mole ratio of CO2/CH4in the gas phase on the separation of CO2 from mixtures of CO2/CH4 were also investigated. Our DFT calculation results show that the CO2 moleculehas higher adsorption energy than that of CH4, which implies that it can be easily adsorbed to the phosphorene surface than CH4. Detailed GCMC simulations reveal that the phosphorene slit pore has a high performance in separating CO2fromnature gas and achieves the highest gas selectivity at H = 1.0 nm at pressures lower than 0.1 MPa. Moreover, the selectivity of CO2 overCO2/CH4gas mixture increases with increasing the mole ratio of CO2/CH4due to the enhanced adsorbate-adsorbent interactions for the favorable component. Therefore, it is suggested that the phosphorene is a promising candidate for natural gas purification and possessing practical potential applications in gas adsorption.

  13. Comparison of ocean surface solar irradiance in the GLA General Circulation Model and satellite-based calculations

    SciTech Connect

    Chertock, B. ); Sud, Y.C. )

    1993-03-01

    A global, 7-year satellite-based record of ocean surface solar irradiance (SSI) is used to assess the realism of ocean SSI simulated by the nine-layer Goddard Laboratory for Atmospheres (GLA) General Circulation Model (GCM). January and July climatologies of net SSI produced by the model are compared with corresponding satellite climatologies for the world oceans between 54[degrees]N and 54[degrees]S. This comparison of climatologies indicates areas of strengths and weaknesses in the GCM treatment of cloud-radiation interactions, the major source of model uncertainty. Realism of ocean SSI is also important for applications such as incorporating the GLA GCM into a coupled ocean-atmosphere GCM. The results show that the GLA GCM simulates too much SSI in the extratropics and too little in the tropics, especially in the summer hemisphere. These discrepancies reach magnitudes of 60 W m[sup [minus]2] and more. The discrepancies are particularly large in the July case off the western coast of North America. In this region of persistent marine stratus, the GCM climatological values exceed the satellite climatological values by as much as 131 W m[sup [minus]2]. Positive and negative discrepancies in SSI are shown to be consistent with discrepancies in planetary albedo.

  14. Comparison of ocean surface solar irradiance in the GLA General Circulation Model and satellite-based calculations

    NASA Technical Reports Server (NTRS)

    Chertock, Beth; Sud, Y. C.

    1993-01-01

    A global, 7-year satellite-based record of ocean surface solar irradiance (SSI) is used to assess the realism of ocean SSI simulated by the nine-layer Goddard Laboratory for Atmospheres (GLA) General Circulation Model (GCM). January and July climatologies of net SSI produced by the model are compared with corresponding satellite climatologies for the world oceans between 54 deg N and 54 deg S. This comparison of climatologies indicates areas of strengths and weaknesses in the GCM treatment of cloud-radiation interactions, the major source of model uncertainty. Realism of ocean SSI is also important for applications such as incorporating the GLA GCM into a coupled ocean-atmosphere GCM. The results show that the GLA GCM simulates too much SSI in the extratropics and too little in the tropics, especially in the summer hemisphere. These discrepancies reach magnitudes of 60 W/sq m and more. The discrepancies are particularly large in the July case off the western coast of North America. Positive and negative discrepancies in SSI are shown to be consistent with discrepancies in planetary albedo.

  15. GROUND WATER ISSUE - CALCULATION AND USE OF FIRST-ORDER RATE CONSTANTS FOR MONITORED NATURAL ATTENUATION STUDIES

    EPA Science Inventory

    This issue paper explains when and how to apply first-order attenuation rate constant calculations in monitored natural attenuation (MNA) studies. First-order attenuation rate constant calculations can be an important tool for evaluating natural attenuation processes at ground-wa...

  16. Prediction of Severe Accident Counter Current Natural Circulation Flows in the Hot Leg of a Pressurized Water Reactor

    SciTech Connect

    Boyd, Christopher F.

    2006-07-01

    During certain phases of a severe accident in a pressurized water reactor (PWR), the core becomes uncovered and steam carries heat to the steam generators through natural circulation. For PWR's with U-tube steam generators and loop seals filled with water, a counter current flow pattern is established in the hot leg. This flow pattern has been experimentally observed and has been predicted using computational fluid dynamics (CFD). Predictions of severe accident behavior are routinely carried out using severe accident system analysis codes such as SCDAP/RELAP5 or MELCOR. These codes, however, were not developed for predicting the three-dimensional natural circulation flow patterns during this phase of a severe accident. CFD, along with a set of experiments at 1/7. scale, have been historically used to establish the flow rates and mixing for the system analysis tools. One important aspect of these predictions is the counter current flow rate in the nearly 30 inch diameter hot leg between the reactor vessel and steam generator. This flow rate is strongly related to the amount of energy that can be transported away from the reactor core. This energy transfer plays a significant role in the prediction of core failures as well as potential failures in other reactor coolant system piping. CFD is used to determine the counter current flow rate during a severe accident. Specific sensitivities are completed for parameters such as surge line flow rates, hydrogen content, as well as vessel and steam generator temperatures. The predictions are carried out for the reactor vessel upper plenum, hot leg, a portion of the surge line, and a steam generator blocked off at the outlet plenum. All predictions utilize the FLUENT V6 CFD code. The volumetric flow in the hot leg is assumed to be proportional to the square root of the product of normalized density difference, gravity, and hydraulic diameter to the 5. power. CFD is used to determine the proportionality constant in the range

  17. Evaluation of the efficiency and accuracy of new methods for atmospheric opacity and radiative transfer calculations in planetary general circulation model simulations

    NASA Astrophysics Data System (ADS)

    Zube, Nicholas Gerard; Zhang, Xi; Natraj, Vijay

    2016-10-01

    General circulation models often incorporate simple approximations of heating between vertically inhomogeneous layers rather than more accurate but computationally expensive radiative transfer (RT) methods. With the goal of developing a GCM package that can model both solar system bodies and exoplanets, it is vital to examine up-to-date RT models to optimize speed and accuracy for heat transfer calculations. Here, we examine a variety of interchangeable radiative transfer models in conjunction with MITGCM (Hill and Marshall, 1995). First, for atmospheric opacity calculations, we test gray approximation, line-by-line, and correlated-k methods. In combination with these, we also test RT routines using 2-stream DISORT (discrete ordinates RT), N-stream DISORT (Stamnes et al., 1988), and optimized 2-stream (Spurr and Natraj, 2011). Initial tests are run using Jupiter as an example case. The results can be compared in nine possible configurations for running a complete RT routine within a GCM. Each individual combination of opacity and RT methods is contrasted with the "ground truth" calculation provided by the line-by-line opacity and N-stream DISORT, in terms of computation speed and accuracy of the approximation methods. We also examine the effects on accuracy when performing these calculations at different time step frequencies within MITGCM. Ultimately, we will catalog and present the ideal RT routines that can replace commonly used approximations within a GCM for a significant increase in calculation accuracy, and speed comparable to the dynamical time steps of MITGCM. Future work will involve examining whether calculations in the spatial domain can also be reduced by smearing grid points into larger areas, and what effects this will have on overall accuracy.

  18. Absence of circulating natural killer (NK) cells in a child with erythrophagocytic lymphohistiocytosis lacking NK cell activity

    SciTech Connect

    Kawai, H.; Komiyama, A.; Aoyama, K.; Miyagawa, Y.; Akabane, T.

    1988-06-01

    A 5-year-old girl who was diagnosed as having erythrophagocytic lymphohistiocytosis died at age 9 years. Peripheral lymphocytes from the patient persistently lacked natural killer (NK) cell activity during the 4-year observation period: the percent lysis values as measured by a 4-hr /sup 51/Cr release assay at a 40:1 effector:target ratio were below 1.0% against K562 and Molt-4 cells as compared with the normal lymphocyte value (mean +/- SD) of 46.2% +/- 5.8% and 43.9% +/- 6.7%, respectively. The patient's lymphocytes never developed NK cell activity by their incubation with target cells for longer time periods or by their stimulation with interferon-alpha, interleukin-2, or polyinosinic-polycytidilic acid. Single cell-in-agarose assay showed the absence of target-binding cells (TBCs): TBC numbers were below 0.3% as compared with the normal lymphocyte value of 8.1% +/- 1.3% (mean +/- SD). Flow cytometry showed a marked decrease in Leu-7+ cells (1.7%) and the absence of Leu-11+ cells (0.4%) in the peripheral blood. These results first demonstrate a case of erythrophagocytic lymphohistiocytosis in which there is the lack of NK cell activity due to the absence of circulating NK cells.

  19. Laser anemometry measurements of natural circulation flow in a scale model PWR reactor system. [Pressurized Water Reactor

    NASA Technical Reports Server (NTRS)

    Kadambi, J. R.; Schneider, S. J.; Stewart, W. A.

    1986-01-01

    The natural circulation of a single phase fluid in a scale model of a pressurized water reactor system during a postulated grade core accident is analyzed. The fluids utilized were water and SF6. The design of the reactor model and the similitude requirements are described. Four LDA tests were conducted: water with 28 kW of heat in the simulated core, with and without the participation of simulated steam generators; water with 28 kW of heat in the simulated core, with the participation of simulated steam generators and with cold upflow of 12 lbm/min from the lower plenum; and SF6 with 0.9 kW of heat in the simulated core and without the participation of the simulated steam generators. For the water tests, the velocity of the water in the center of the core increases with vertical height and continues to increase in the upper plenum. For SF6, it is observed that the velocities are an order of magnitude higher than those of water; however, the velocity patterns are similar.

  20. The impact of horizontal resolution of density field on the calculation of the Atlantic meridional overturning circulation at 34°S

    NASA Astrophysics Data System (ADS)

    Stepanov, Vladimir N.; Iovino, Doroteaciro; Masina, Simona; Storto, Andrea; Cipollone, Andrea

    2016-06-01

    The Atlantic meridional overturning circulation and meridional heat transport (hereafter the AMOC and MHT) at 34°S as simulated by global 1/16° eddy-rich (henceforth GLOB16) and ¼° eddy-permitting (GLOB4) models are compared with observational estimates. Three different methods are used for calculating the modeled AMOC: the first method (MOCmod) is based on simulated velocity fields, while the second (MOCob) relies on the same assumptions as available observed-derived estimates. The third method (MOCob2) is also based on hydrostatic and geostrophic relationships, but relative to a barotropic circulation instead of the definition of velocity at a specific reference depth. All methods correctly reproduce the time-mean GLOB16 AMOC strength, but the value of the non-Ekman component of the GLOB16 AMOC is only about 75% of the observed-derived estimate. The GLOB16 MHT is also significantly less than observation value (slightly more than 60% of the observed). However, the mean AMOC and MHT values at 34°S obtained with coarser resolution GLOB4 model are comparable with the observed-derived estimates. Possible causes for the differences between the eddy-rich model and observational data are studied. It is shown that the density field from the eddy-rich model has high temporal variability along 34°S with spatial scale of about two hundred km that can be due to mesoscale variations, caused by Agulhas "leakage." This results in the decrease of the mean meridional geostrophic velocity, which leads to smaller values of the AMOC and MHT in GLOB16: subsampling GLOB16 density on ¼° or ½° longitude grid along 34°S for MOCob calculation significantly increases the AMOC values. The findings in this paper provide guidance in understanding AMOC and MHT dissimilarities between observation-based estimates and eddy-rich ocean models at 34°S.

  1. Experimental Investigation of Natural-Circulation Flow Behavior Under Low-Power/Low-Pressure Conditions in the Large-Scale PANDA Facility

    SciTech Connect

    Auban, Olivier; Paladino, Domenico; Zboray, Robert

    2004-12-15

    Twenty-five tests have been carried out in the large-scale thermal-hydraulic facility PANDA to investigate natural-circulation and stability behavior under low-pressure/low-power conditions, when void flashing might play an important role. This work, which extends the current experimental database to a large geometric scale, is of interest notably with regard to the start-up procedures in natural-circulation-cooled boiling water reactors. It should help the understanding of the physical phenomena that may cause flow instability in such conditions and can be used for validation of thermal-hydraulics system codes. The tests were performed at a constant power, balanced by a specific condenser heat removal capacity. The test matrix allowed the reactor pressure vessel power and pressure to be varied, as well as other parameters influencing the natural-circulation flow. The power spectra of flow oscillations showed in a few tests a major and unique resonance peak, and decay ratios between 0.5 and 0.9 have been found. The remainder of the tests showed an even more pronounced stable behavior. A classification of the tests is presented according to the circulation modes (from single-phase to two-phase flow) that could be assumed and particularly to the importance and the localization of the flashing phenomenon.

  2. Circadian rhythm in circulating CD16-positive natural killer (NK) cells in macaque monkeys, implication of plasma cortisol levels.

    PubMed

    Terao, Keiji; Suzuki, Juri; Ohkura, Satoshi

    2002-10-01

    The daily change in both percentage and absolute number of circulating major lymphocyte subset was determined with young Japanese monkeys and rhesus monkeys. The blood sample was collected at four hour-intervals beginning at 16:00 for 24 hours under the condition of applying tethering system by which blood samples could be collected without restraint. During the dark period (from 20:00 to 08:00), the number of peripheral lymphocytes increased and that of granulocytes decreased, resulting in no significant change in the number of total peripheral white blood cells. The absolute number of CD4+ T, CD8+ T, and CD20+ B cells showed the significant daily change similar to that in number of peripheral lymphocytes, indicating no proportional change in these subsets. The typical proportional change was observed in CD16+ natural killer (NK) cells and the percentage of CD16+ cells decreased during dark period (from 20:00 to 04:00) and increased in the morning (from 08:00 to 12:00). The NK activity determined by killing K562 target cells showed the same changing pattern as that of percentage in CD16+ NK cells. The changing pattern of both percentage and activity of NK cells was consistent with that of plasma cortisol levels. In addition, the intravenous injection of 300 g/kg of cortisol induced increase in plasma cortisol levels and decrease in percentage of CD16+ NK cells during the first 60 min after cortisol injection. These results strongly suggest that the levels of peripheral functional CD16+ NK cells might be directly regulated by plasma cortisol level in macaque monkeys.

  3. Increased circulating microRNAs miR-342-3p and miR-21-5p in natural sheep prion disease.

    PubMed

    Sanz Rubio, David; López-Pérez, Óscar; de Andrés Pablo, Álvaro; Bolea, Rosa; Osta, Rosario; Badiola, Juan J; Zaragoza, Pilar; Martín-Burriel, Inmaculada; Toivonen, Janne M

    2017-02-01

    Scrapie is a transmissible spongiform encephalopathy (TSE), or prion disease, of sheep and goats. As no simple diagnostic tests are yet available to detect TSEs in vivo, easily accessible biomarkers could facilitate the eradication of scrapie agents from the food chain. To this end, we analysed by quantitative reverse transcription PCR a selected set of candidate microRNAs (miRNAs) from circulating blood plasma of naturally infected, classical scrapie sheep that demonstrated clear scrapie symptoms and pathology. Significant scrapie-associated increase was repeatedly found for miR-342-3p and miR-21-5p. This is the first demonstration, to our knowledge, of circulating miRNA alterations in any animal suffering from TSE. Genome-wide expression studies are warranted to investigate the true depth of miRNA alterations in naturally occurring TSEs, especially in presymptomatic animals, as the presented study demonstrates the potential feasibility of miRNAs as circulating TSE biomarkers.

  4. A study on the effect of various design parameters on the natural circulation flow rate of the ex-vessel core catcher cooling system of EU-APR1400

    SciTech Connect

    Rhee, B. W.; Ha, K. S.; Park, R. J.; Song, J. H.

    2012-07-01

    In this paper, a study on the effect of various design parameters such as the channel gap width, heat flux distribution, down-comer pipe size and two-phase flow slip ratio on the natural circulation flow rate is performed based on a physical model for a natural circulation flow along the flow path of the ex-vessel core catcher cooling system of an EU-APR1400, and these effects on the natural circulation flow rate are analyzed and compared with the minimum flow rate required for the safe operation of the system. (authors)

  5. Parameter Calculation Technique for the Waste Treatment Facilities Using Naturally-Aerated Blocks in the Bog Ecosystems

    NASA Astrophysics Data System (ADS)

    Akhmed-Ogly, K. V.; Savichev, O. G.; Tokarenko, O. G.; Pasechnik, E. Yu; Reshetko, M. V.; Nalivajko, N. G.; Vlasova, M. V.

    2014-08-01

    Technique for the domestic wastewater treatment in the small residential areas and oil and gas facilities of the natural and man-made systems including a settling tank for mechanical treatment and a biological pond with peat substrate and bog vegetation for biological treatment has been substantiated. Technique for parameters calculation of the similar natural and man-made systems has been developed. It was proven that effective treatment of wastewater can be performed in Siberia all year round.

  6. 40 CFR 98.233 - Calculating GHG emissions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... gas water content. (iii) Outlet natural gas water content. (iv) Absorbent circulation pump type...) (c) Natural gas driven pneumatic pump venting. Calculate CH4 and CO2 emissions from natural gas driven pneumatic pump venting using Equation W-2 of this section. Natural gas driven pneumatic...

  7. Organic complexation of rare earth elements in natural waters: Evaluating model calculations from ultrafiltration data

    NASA Astrophysics Data System (ADS)

    Pourret, Olivier; Davranche, Mélanie; Gruau, Gérard; Dia, Aline

    2007-06-01

    The Stockholm Humic Model (SHM) and Humic Ion-Binding Models V and VI were compared for their ability to predict the role of dissolved organic matter (DOM) in the speciation of rare earth elements (REE) in natural waters. Unlike Models V and VI, SHM is part of a speciation code that also allows us to consider dissolution/precipitation, sorption/desorption and oxidation/reduction reactions. In this context, it is particularly interesting to test the performance of SHM. The REE specific equilibrium constants required by the speciation models were estimated using linear free-energy relationships (LFER) between the first hydrolysis constants and the stability constants for REE complexation with lactic and acetic acid. Three datasets were used for the purpose of comparison: (i) World Average River Water (Dissolved Organic Carbon (DOC) = 5 mg L -1), previously investigated using Model V, was reinvestigated using SHM and Model VI; (ii) two natural organic-rich waters (DOC = 18-24 mg L -1), whose REE speciation has already been determined with both Model V and ultrafiltration studies, were also reinvestigated using SHM and Model VI; finally, (iii) new ultrafiltration experiments were carried out on samples of circumneutral-pH (pH 6.2-7.1), organic-rich (DOC = 7-20 mg L -1) groundwaters from the Kervidy-Naizin and Petit-Hermitage catchments, western France. The results were then compared with speciation predictions provided by Model VI and SHM, successively. When applied to World Average River Water, both Model VI and SHM yield comparable results, confirming the earlier finding that a large fraction of the dissolved REE in rivers occurs as organic complexes This implies that the two models are equally valid for calculating REE speciation in low-DOC waters at circumneutral-pH. The two models also successfully reproduced ultrafiltration results obtained for DOC-rich acidic groundwaters and river waters. By contrast, the two models yielded different results when compared to

  8. A scaling study of the natural circulation flow of the ex-vessel core catcher cooling system of EU-APR1400 for designing a scale-down test facility for design verification

    SciTech Connect

    Rhee, B. W.; Ha, K. S.; Park, R. J.; Song, J. H.; Revankar, S. T.

    2012-07-01

    In this paper a scaling study on the steady state natural circulation flow along the flow path of the ex vessel core catcher cooling system of EU-APR1400 is described, and the scaling criteria for reproducing the same steady state thermalhydraulic characteristics of the natural circulation flow as a prototype core catcher cooling system in the scale-down test facility are derived in terms of the down-comer pipe diameter and orifice resistance. (authors)

  9. General contraction of Gaussian basis sets. II - Atomic natural orbitals and the calculation of atomic and molecular properties

    NASA Technical Reports Server (NTRS)

    Almlof, Jan; Taylor, Peter R.

    1990-01-01

    A recently proposed scheme for using natural orbitals from atomic configuration interaction wave functions as a basis set for linear combination of atomic orbitals (LCAO) calculations is extended for the calculation of molecular properties. For one-electron properties like multipole moments, which are determined largely by the outermost regions of the molecular wave function, it is necessary to increase the flexibility of the basis in these regions. This is most easily done by uncontracting the outermost Gaussian primitives, and/or by adding diffuse primitives. A similar approach can be employed for the calculation of polarizabilities. Properties which are not dominated by the long-range part of the wave function, such as spectroscopic constants or electric field gradients at the nucleus, can generally be treated satisfactorily with the original atomic natural orbital sets.

  10. General contraction of Gaussian basis sets. Part 2: Atomic natural orbitals and the calculation of atomic and molecular properties

    NASA Technical Reports Server (NTRS)

    Almloef, Jan; Taylor, Peter R.

    1989-01-01

    A recently proposed scheme for using natural orbitals from atomic configuration interaction (CI) wave functions as a basis set for linear combination of atomic orbitals (LCAO) calculations is extended for the calculation of molecular properties. For one-electron properties like multipole moments, which are determined largely by the outermost regions of the molecular wave function, it is necessary to increase the flexibility of the basis in these regions. This is most easily done by uncontracting the outmost Gaussian primitives, and/or by adding diffuse primitives. A similar approach can be employed for the calculation of polarizabilities. Properties which are not dominated by the long-range part of the wave function, such as spectroscopic constants or electric field gradients at the nucleus, can generally be treated satisfactorily with the original atomic natural orbital (ANO) sets.

  11. Alkanes in Natural and Synthetic Petroleums: Comparison of Calculated and Actual Compositions.

    PubMed

    Friedel, R A; Sharkey, A G

    1963-03-22

    A similarity exists between the low molecular weight alkane isomers in crude oil and Fischer-Tropsch catalytic synthesis products. The composition of the C(4) through C(7) alkane isomers in a crude oil was calculated quantitatively with the equations previously used to calculate the alkane isomers in Fischer-Tropsch products. These results may have significance in ascertaining the origin of the volatile hydrocarbons in crude oils.

  12. Study on bubbly flow behavior in natural circulation reactor by thermal-hydraulic simulation tests with SF6-Gas and ethanol liquid

    NASA Astrophysics Data System (ADS)

    Kondo, Yoshiyuki; Suga, Keishi; Hibi, Koki; Okazaki, Toshihiko; Komeno, Toshihiro; Kunugi, Tomoaki; Serizawa, Akimi; Yoneda, Kimitoshi; Arai, Takahiro

    2009-02-01

    An advanced experimental technique has been developed to simulate two-phase flow behavior in a light water reactor (LWR). The technique applies three kinds of methods; (1) use of sulfur-hexafluoride (SF6) gas and ethanol (C2H5OH) liquid at atmospheric temperature and a pressure less than 1.0MPa, where the fluid properties are similar to steam-water ones in the LWR, (2) generation of bubble with a sintering tube, which simulates bubble generation on heated surface in the LWR, (3) measurement of detailed bubble distribution data with a bi-optical probe (BOP), (4) and measurement of liquid velocities with the tracer liquid. This experimental technique provides easy visualization of flows by using a large scale experimental apparatus, which gives three-dimensional flows, and measurement of detailed spatial distributions of two-phase flow. With this technique, we have carried out experiments simulating two-phase flow behavior in a single-channel geometry, a multi-rod-bundle one, and a horizontal-tube-bundle one on a typical natural circulation reactor system. Those experiments have clarified a) a flow regime map in a rod bundle on the transient region between bubbly and churn flow, b) three-dimensional flow behaviour in rod-bundles where inter-subassembly cross-flow occurs, c) bubble-separation behavior with consideration of reactor internal structures. The data have given analysis models for the natural circulation reactor design with good extrapolation.

  13. Steady state boiling crisis in a helium vertically heated natural circulation loop - Part 1: Critical heat flux, boiling crisis onset and hysteresis

    NASA Astrophysics Data System (ADS)

    Furci, H.; Baudouy, B.; Four, A.; Meuris, C.

    2016-01-01

    Experiments were conducted on a 2-m high two-phase helium natural circulation loop operating at 4.2 K and 1 atm. The same loop was used in two experiments with different heated section internal diameter (10 and 6 mm). The power applied on the heated section wall was controlled in increasing and decreasing sequences, and temperature along the section, mass flow rate and pressure drop evolutions were recorded. The values of critical heat flux (CHF) were found at different positions of the test section, and the post-CHF regime was studied. The predictions of CHF by existing correlations were good in the downstream portion of the section, however CHF anomalies have been observed near the entrance, in the low quality region. In resonance with this, the re-wetting of the surface has distinct hysteresis behavior in each of the two CHF regions. Furthermore, hydraulics effects of crisis, namely on friction, were studied (Part 2). This research is the starting point to future works addressing transients conducing to boiling crisis in helium natural circulation loops.

  14. In Oregon, the EPA calculates nature's worth now and in the future

    EPA Science Inventory

    Ecosystem services are the many life-sustaining benefits we receive from nature — clean air and water, food and fiber production, greenhouse gas regulation, maintenance of biodiversity, etc. These ecosystem services are vital to our well-being, yet they are limited and often tak...

  15. Calculation of indoor effective dose factors in ORNL phantoms series due to natural radioactivity in building materials.

    PubMed

    Krstic, D; Nikezic, D

    2009-10-01

    In this paper the effective dose in the age-dependent ORNL phantoms series, due to naturally occurring radionuclides in building materials, was calculated. The absorbed doses for various organs or human tissues have been calculated. The MCNP-4B computer code was used for this purpose. The effective dose was calculated according to ICRP Publication 74. The obtained values of dose conversion factors for a standard room are: 1.033, 0.752 and 0.0538 nSv h-1 per Bq kg-1 for elements of the U and Th decay series and for the K isotope, respectively. The values of effective dose agreed generally with those found in the literature, although the values estimated here for elements of the U series were higher in some cases.

  16. Calculation of absorbed dose around a facility for disposing of low activity natural radioactive waste (C3-dump).

    PubMed

    Jansen, J T M; Zoetelief, J

    2005-01-01

    A C3-dump is a facility for disposing of low activity natural radioactive waste containing the uranium series 238U, the thorium series 232Th and 40K. Only the external radiation owing to gamma rays, X-rays and annihilation photons is considered in this study. For two situations--the semi-infinite slab and the tourist geometry--the conversion coefficients from specific activity to air kerma rate at 1 m above the relevant level are calculated. In the first situation the waste material is in contact with the air but in the tourist geometry it is covered with a 1.35 m thick layer. For the calculations, the Monte Carlo radiation transport code MCNP is used. The yield and photon energy for each radionuclide are according to the database of Oak Ridge National Laboratory. For the tourist situation, the depth-dose distribution through the covering layer is calculated and extrapolated to determine the exit dose.

  17. Studies of Phase Change Materials and a Latent Heat Storage Unit Used for a Natural Circulation Cooling/Latent Heat Storage System

    NASA Astrophysics Data System (ADS)

    Sakitani, Katsumi; Honda, Hiroshi

    Experiments were performed to investigate feasibility of using organic materials as a PCM for a latent heat storage unit of a natural circulation cooling/latent heat storage system. This system was designed to cool a shelter accommodating telecommunication equipment located in subtropical deserts or similar regions without using a power source. Taking into account practical considerations and the results of various experiments regarding the thermodynamic properties, thermal degradation, and corrosiveness to metals, lauric acid and iron was selected for the PCM and the latent heat storage unit material, respectively. Cyclic heating and cooling of the latent heat storage unit undergoing solid-liquid phase change was repeated for more than 430 days. The results showed that the heating-cooling curve was almost unchanged between the early stage and the 1,870th cycle. It was concluded that the latent heat storage unit could be used safely for more than ten years as a component of the cooling system.

  18. Phenotypic Features of Circulating Leukocytes from Non-human Primates Naturally Infected with Trypanosoma cruzi Resemble the Major Immunological Findings Observed in Human Chagas Disease

    PubMed Central

    Mattoso-Barbosa, Armanda Moreira; Perdigão-de-Oliveira, Marcelo; Costa, Ronaldo Peres; Elói-Santos, Silvana Maria; Gomes, Matheus de Souza; do Amaral, Laurence Rodrigues; Teixeira-Carvalho, Andréa; Martins-Filho, Olindo Assis; Dick, Edward J.; Hubbard, Gene B.; VandeBerg, Jane F.; VandeBerg, John L.

    2016-01-01

    Background Cynomolgus macaques (Macaca fascicularis) represent a feasible model for research on Chagas disease since natural T. cruzi infection in these primates leads to clinical outcomes similar to those observed in humans. However, it is still unknown whether these clinical similarities are accompanied by equivalent immunological characteristics in the two species. We have performed a detailed immunophenotypic analysis of circulating leukocytes together with systems biology approaches from 15 cynomolgus macaques naturally infected with T. cruzi (CH) presenting the chronic phase of Chagas disease to identify biomarkers that might be useful for clinical investigations. Methods and Findings Our data established that CH displayed increased expression of CD32+ and CD56+ in monocytes and enhanced frequency of NK Granzyme A+ cells as compared to non-infected controls (NI). Moreover, higher expression of CD54 and HLA-DR by T-cells, especially within the CD8+ subset, was the hallmark of CH. A high level of expression of Granzyme A and Perforin underscored the enhanced cytotoxicity-linked pattern of CD8+ T-lymphocytes from CH. Increased frequency of B-cells with up-regulated expression of Fc-γRII was also observed in CH. Complex and imbricate biomarker networks demonstrated that CH showed a shift towards cross-talk among cells of the adaptive immune system. Systems biology analysis further established monocytes and NK-cell phenotypes and the T-cell activation status, along with the Granzyme A expression by CD8+ T-cells, as the most reliable biomarkers of potential use for clinical applications. Conclusions Altogether, these findings demonstrated that the similarities in phenotypic features of circulating leukocytes observed in cynomolgus macaques and humans infected with T. cruzi further supports the use of these monkeys in preclinical toxicology and pharmacology studies applied to development and testing of new drugs for Chagas disease. PMID:26808481

  19. Ab initio no-core configuration interaction calculations of electromagnetic observables for p-shell nuclei using natural orbitals

    NASA Astrophysics Data System (ADS)

    Constantinou, Chrysovalantis; Caprio, Mark A.; Vary, James P.; Maris, Pieter

    2016-09-01

    The goal of ab initio nuclear theory is to provide quantitative predictions of nuclear observables, by solving the many-body problem starting from the internucleon interaction. The solution of the many-body problem involves large spaces with dimensions that grow fast with the number of nucleons and single-particle states included in the space. Convergence of nuclear observables in the employed space using an adequate set of single-particle orbitals is essential for making quantitative predictions. Long-range nuclear observables, such as the matrix elements of the E 2 operator, converge slowly when conventional oscillator single-particle orbitals are used for no-core configuration interaction (NCCI) calculations. Natural orbitals, obtained by diagonalizing the one-body density matrix from an initial NCCI calculation in the harmonic oscillator basis, provide accelerated convergence since they are adapted to the properties of the many-body wave function of the nucleus under study. We explore the convergence of electromagnetic observables of p-shell nuclei obtained using natural orbitals for NCCI calculations. Supported by the US DOE under Grants DE-FG02-95ER-40934, DESC0008485 (SciDAC/NUCLEI), and DE-FG02-87ER40371. Computational resources provided by NERSC (supported by US DOE Contract DE-AC02-05CH11231) and the Notre Dame Center for Research Computing.

  20. Epoxides, cyclic sulfites, and sulfate from natural pentacyclic triterpenoids: theoretical calculations and chemical transformations.

    PubMed

    García-Granados, Andrés; López, Pilar E; Melguizo, Enrique; Moliz, Juan N; Parra, Andrés; Simeó, Yolanda; Dobado, José A

    2003-06-13

    Several triterpenic derivatives, with the A-ring functionalized, were semisynthesized from oleanolic and maslinic acids. The reactivities of sulfites, sulfate, and epoxides in these triterpene compounds were investigated under different reaction conditions. Moreover, contracted A-ring triterpenes (five-membered rings) were obtained, by different treatments of the sulfate 7. From the epoxide 8, deoxygenated and halohydrin derivatives were semisynthesized with several nucleophiles. Ozonolysis and Beckmann reactions were used to yield 4-aza compounds, from five-membered ring olanediene triterpenes. The X-ray structure of sulfate 7 is given and compared with density functional theory geometries. Theoretical (13)C and (1)H chemical shifts (gauge-invariant atomic orbital method at the B3LYP/6-31G*//B3LYP/6-31G* level) and (3)J(H,H) coupling constants were calculated for compounds 5-9 and 34-36, identifying the (R)- or (S)-sulfur and alpha- or beta-epoxide configurations together with 4-aza or 3-aza structures.

  1. CFD Calculation of Internal Natural Convection in the Annulus between Horizontal Concentric Cylinders

    SciTech Connect

    N.D. Francis, Jr; M.T. Itamura; S.W. Webb; D.L. James

    2002-10-01

    The objective of this heat transfer and fluid flow study is to assess the ability of a computational fluid dynamics (CFD) code to reproduce the experimental results, numerical simulation results, and heat transfer correlation equations developed in the literature for natural convection heat transfer within the annulus of horizontal concentric cylinders. In the literature, a variety of heat transfer expressions have been developed to compute average equivalent thermal conductivities. However, the expressions have been primarily developed for very small inner and outer cylinder radii and gap-widths. In this comparative study, interest is primarily focused on large gap widths (on the order of half meter or greater) and large radius ratios. From the steady-state CFD analysis it is found that the concentric cylinder models for the larger geometries compare favorably to the results of the Kuehn and Goldstein correlations in the Rayleigh number range of about 10{sup 5} to 10{sup 8} (a range that encompasses the laminar to turbulent transition). For Rayleigh numbers greater than 10{sup 8}, both numerical simulations and experimental data (from the literature) are consistent and result in slightly lower equivalent thermal conductivities than those obtained from the Kuehn and Goldstein correlations.

  2. An improved calculation of the exergy of natural resources for exergetic life cycle assessment (ELCA).

    PubMed

    De Meester, Bram; Dewulf, Jo; Janssens, Arnold; Van Langenhove, Herman

    2006-11-01

    The focus in environmental research is shifting from emission abatement to critical process analysis, including assessment of resource consumption. The exergy theory offers a thermodynamic methodology to account for the consumption of natural resources. However, exergy data on mineral resources available in the literature are inadequate to apply to exergetic life cycle analysis, due to incompleteness, inconsistencies, and a dated thermochemical basis. An uncertainty assessment of the data has to be performed as well. In this work, three recent thermochemical databases were applied to evaluate the chemical exergy of 85 elements and 73 minerals, 21 of which had not yet been quantified in the literature. The process required the choice of a new reference species for aluminum. Muscovite was selected, giving rise to a chemical exergy of 809.4 kJ/mol for aluminum. The theory proved to be robust for the exergy of chemical elements, as exergy values differing by 1.2% on average from most recent literature were found. On the contrary, the exergy values for minerals differed by factors up to 14 from literature values, due to the application of recent thermochemical values and consistently selected reference species. The consistent dataset of this work will enable straightforward resource intake evaluation through an exergetic life cycle assessment.

  3. Circulating Natural IgM Antibodies Against Angiogenin in the Peripheral Blood Sera of Patients with Osteosarcoma as Candidate Biomarkers and Reporters of Tumorigenesis

    PubMed Central

    Savitskaya, Yulia A.; Rico, Genaro; Linares, Luis; González, Roberto; Téllez, René; Estrada, Eréndira; Marín, Norma; Martínez, Elisa; Alfaro, Alfonso; Ibarra, Clemente

    2010-01-01

    Background: Tumor immunology research has led to the identification of a number of tumor-associated self antigens, suggesting that most tumors trigger an immunogenic response, as is the case in osteosarcoma, where the detection of natural serum IgM antibodies might achieve the diagnosis of osteosarcoma. Natural IgM antibodies to tumor-associated proteins may expand the number of available tumor biomarkers for osteosarcoma and may be used together in a serum profile to enhance test sensitivity and specificity. Natural IgM antibodies can be consistently detected in the peripheral blood sera months to years before the tumor is diagnosed clinically. The study of the level of a potential biomarker many months (or years) prior to diagnosis is fundamentally important. Integrated circulating and imaging markers in clinical practice treating osteosarcoma have potential applications for controlling tumor angiogenesis. Objectives: To study the expression of natural IgM antibodies to the tumor antigens of angiogenesis in the peripheral blood sera of osteosarcoma patients and healthy individuals, and to develop serum-based predictive biomarkers. Methods: Peripheral venous blood samples were collected from 117 osteosarcoma patients and 117 patients with other tumors. All diagnosis was histologically confirmed. Staging of patients was performed according to the Enneking Surgical Staging System. The control group consisted of 117 age- and sex- matched healthy individuals. In this study, novel immunoconjugates were designed, synthesized and then used to develop a rapid, specific and sensitive enzyme-linked immunosorbent assay (ELISA) method to detect angiogenin (ANG)–IgM directly in the peripheral blood sera of humans. Results: Serum ANG–IgM levels are significantly higher in osteosarcoma patients than in healthy individuals (P < 0.005). Serum ANG–IgM levels varied widely, but were highly dependent on the concentration of IgM (r = 0.85; P < 0.0005). We found ANG–IgM in the

  4. 57Fe Mössbauer spectroscopy, X-ray single-crystal diffractometry, and electronic structure calculations on natural alexandrite

    NASA Astrophysics Data System (ADS)

    Weber, Sven-Ulf; Grodzicki, Michael; Lottermoser, Werner; Redhammer, Günther J.; Tippelt, Gerold; Ponahlo, Johann; Amthauer, Georg

    2007-09-01

    Natural alexandrite Al2BeO4:Cr from Malyshevo near Terem Tschanka, Sverdlovsk, Ural, Russia, has been characterized by 57Fe Mössbauer spectroscopy, electron microprobe, X-ray single-crystal diffractometry and by electronic structure calculations in order to determine oxidation state and location of iron. The sample contains 0.3 wt% of total iron oxide. The 57Fe Mössbauer spectrum can be resolved into three doublets. Two of them with hyperfine parameters typical for octahedrally coordinated high-spin Fe3+ and Fe2+, respectively, are assigned to iron substituting for Al in the octahedral M2-site. The third doublet is attributed to Fe3+ in hematite. Electronic structure calculations in the local spin density approximation are in reasonable agreement with experimental data provided that expansion and/or distortion of the coordination octahedra are presumed upon iron substitution. The calculated hyperfine parameters of Fe3+ are almost identical for the M1 and M2 positions, but the calculated ligand-field splitting is by far too large for high-spin Fe3+ on M1.

  5. Experimental Study on Thermal-Hydraulics During Start-Up in the Natural Circulation Boiling Water Reactor Concept: Effects of System Pressure and Increasing Heat Flux on the Geysering and Density Wave Oscillation

    SciTech Connect

    Hadid Subki, M.; Masanori Aritomi; Noriyuki Watanabe; Chaiwat Muncharoen

    2002-07-01

    The feasibility study in thermal-hydraulics for the future light water reactor concept is carried out. One of the essential studies is the two-phase flow instability during start-up in the natural circulation boiling water reactor (BWR) concept. It is anticipated that the occurrence of the two-phase flow instabilities during start-up significantly affects the feasibility concept, since it would cause the complexity in raising and maneuvering the power output. The purpose of the current study is to experimentally investigate the driving mechanism of the geysering and density wave oscillation in the natural circulation loop, induced by a range of system operating pressure and increasing heat flux in vertical parallel channels. The pressure range of atmospheric up to about 4 bars, and the input heat flux range of 0 up to 577 kW/m{sup 2} are applied in these experiments. An experimental apparatus of twin boiling upflow channels to simulate natural circulation flow loop has been designed, constructed and operated. The natural circulation in the loop occurs due to the density difference between two-phase region in the channels and the single-phase liquid in the downcomer. The objective of the study is to propose a rational start-up procedure in which the geysering and density wave oscillation can be prevented during startup, according to its system pressure and heat flux. Previous studies have clarified that three (3) kinds of thermo-hydraulics instabilities may occur during start-up in the natural circulation BWR depending on its procedure and reactor configuration, which are (1) geysering induced by condensation, (2) natural circulation induced by hydrostatic head fluctuation in steam separator, and (3) density wave oscillation. (authors)

  6. Natural Killer Cell Assessment in Peripheral Circulation and Bronchoalveolar Lavage Fluid of Patients with Severe Sepsis: A Case Control Study.

    PubMed

    Souza-Fonseca-Guimaraes, Paulo; Guimaraes, Fernando; Natânia De Souza-Araujo, Caroline; Maria Boldrini Leite, Lidiane; Cristina Senegaglia, Alexandra; Nishiyama, Anita; Souza-Fonseca-Guimaraes, Fernando

    2017-03-12

    Sepsis is a complex systemic inflammatory syndrome, the most common cause of which is attributed to systemic underlying bacterial infection. The complete mechanisms of the dynamic pro- and anti-inflammatory processes underlying the pathophysiology of sepsis remain poorly understood. Natural killer (NK) cells play a crucial role in the pathophysiology of sepsis, leading to exaggerated inflammation due their rapid response and production of pro-inflammatory cytokines such as interferon gamma (IFN-γ). Several studies have already shown that NK cells undergo lymphopenia in the peripheral blood of patients with sepsis. However, our understanding of the mechanisms behind its cellular trafficking and its role in disease development is restricted to studies in animal models. In this study, we aimed to compare the human NK cell subset (CD56(bright or dim)) levels in the peripheral blood and bronchoalveolar lavage (BAL) fluid of sepsis patients. We conducted a case-control study with a sample size consisting of 10 control patients and 23 sepsis patients enrolled at the Hospital Cajuru (Curitiba/PR, Brazil) from 2013 to 2015. Although we were able to confirm previous observations of peripheral blood lymphopenia, no significant differences were detected in NK cell levels in the BAL fluid of these patients. Overall, these findings strengthened the evidence that peripheral blood lymphopenia is likely to be associated with cell death as a consequence of sepsis.

  7. Natural Killer Cell Assessment in Peripheral Circulation and Bronchoalveolar Lavage Fluid of Patients with Severe Sepsis: A Case Control Study

    PubMed Central

    Souza-Fonseca-Guimaraes, Paulo; Guimaraes, Fernando; Natânia De Souza-Araujo, Caroline; Maria Boldrini Leite, Lidiane; Cristina Senegaglia, Alexandra; Nishiyama, Anita; Souza-Fonseca-Guimaraes, Fernando

    2017-01-01

    Sepsis is a complex systemic inflammatory syndrome, the most common cause of which is attributed to systemic underlying bacterial infection. The complete mechanisms of the dynamic pro- and anti-inflammatory processes underlying the pathophysiology of sepsis remain poorly understood. Natural killer (NK) cells play a crucial role in the pathophysiology of sepsis, leading to exaggerated inflammation due their rapid response and production of pro-inflammatory cytokines such as interferon gamma (IFN-γ). Several studies have already shown that NK cells undergo lymphopenia in the peripheral blood of patients with sepsis. However, our understanding of the mechanisms behind its cellular trafficking and its role in disease development is restricted to studies in animal models. In this study, we aimed to compare the human NK cell subset (CD56bright or dim) levels in the peripheral blood and bronchoalveolar lavage (BAL) fluid of sepsis patients. We conducted a case-control study with a sample size consisting of 10 control patients and 23 sepsis patients enrolled at the Hospital Cajuru (Curitiba/PR, Brazil) from 2013 to 2015. Although we were able to confirm previous observations of peripheral blood lymphopenia, no significant differences were detected in NK cell levels in the BAL fluid of these patients. Overall, these findings strengthened the evidence that peripheral blood lymphopenia is likely to be associated with cell death as a consequence of sepsis. PMID:28287491

  8. Impact of aircraft NOx emissions on tropospheric ozone calculated with a chemistry-general circulation model: Sensitivity to higher hydrocarbon chemistry

    NASA Astrophysics Data System (ADS)

    Kentarchos, A. S.; Roelofs, G. J.

    2002-07-01

    A three-dimensional chemistry-general circulation model has been employed to estimate the impact of current aircraft NOx emissions on tropospheric ozone. The model contains a representation of higher hydrocarbon chemistry, implemented by means of the Carbon Bond Mechanism 4 (CBM4), in order to investigate the potential effect of higher hydrocarbons on aircraft-induced ozone changes. Aircraft NOx emissions increase background NOX (= NO + NO2 + NO3 + 2N2O5 + HNO4) concentrations by 50-70 pptv in the upper troposphere over the Northern Hemisphere, and contribute up to 3 ppbv to upper tropospheric background ozone levels. When higher hydrocarbon chemistry is considered in the simulation, the aircraft-induced ozone perturbations are higher by ~12% during summer and the aircraft-induced ozone production efficiency per NOx molecule increases by ~20%, when compared to a simulation without higher hydrocarbon chemistry.

  9. Development of a plant dynamics computer code for analysis of a supercritical carbon dioxide Brayton cycle energy converter coupled to a natural circulation lead-cooled fast reactor.

    SciTech Connect

    Moisseytsev, A.; Sienicki, J. J.

    2007-03-08

    STAR-LM is a lead-cooled pool-type fast reactor concept operating under natural circulation of the coolant. The reactor core power is 400 MWt. The open-lattice core consists of fuel pins attached to the core support plate, (the does not consist of removable fuel assemblies). The coolant flows outside of the fuel pins. The fuel is transuranic nitride, fabricated from reprocessed LWR spent fuel. The cladding material is HT-9 stainless steel; the steady-state peak cladding temperature is 650 C. The coolant is single-phase liquid lead under atmospheric pressure; the core inlet and outlet temperatures are 438 C and 578 C, respectively. (The Pb coolant freezing and boiling temperatures are 327 C and 1749 C, respectively). The coolant is contained inside of a reactor vessel. The vessel material is Type 316 stainless steel. The reactor is autonomous meaning that the reactor power is self-regulated based on inherent reactivity feedbacks and no external power control (through control rods) is utilized. The shutdown (scram) control rods are used for startup and shutdown and to stop the fission reaction in case of an emergency. The heat from the reactor is transferred to the S-CO{sub 2} Brayton cycle in in-reactor heat exchangers (IRHX) located inside the reactor vessel. The IRHXs are shell-and-tube type heat exchangers with lead flowing downwards on the shell side and CO{sub 2} flowing upwards on the tube side. No intermediate circuit is utilized. The guard vessel surrounds the reactor vessel to contain the coolant, in the very unlikely event of reactor vessel failure. The Reactor Vessel Auxiliary Cooling System (RVACS) implementing the natural circulation of air flowing upwards over the guard vessel is used to cool the reactor, in the case of loss of normal heat removal through the IRHXs. The RVACS is always in operation. The gap between the vessels is filled with liquid lead-bismuth eutectic (LBE) to enhance the heat removal by air by significantly reducing the thermal

  10. Successful Antiparasitic Treatment for Cysticercosis Is Associated with a Fast and Marked Reduction of Circulating Antigen Levels in a Naturally Infected Pig Model

    PubMed Central

    Gonzalez, Armando E.; Bustos, Javier A.; Garcia, Hector H.; Rodriguez, Silvia; Zimic, Mirko; Castillo, Yesenia; Praet, Nicolas; Gabriël, Sarah; Gilman, Robert H.

    2015-01-01

    Taenia solium cysticercosis is a common parasitic infection of humans and pigs. We evaluated the posttreatment evolution of circulating parasite-specific antigen titers in 693 consecutive blood samples from 50 naturally infected cysticercotic pigs, which received different regimes of antiparasitic drugs (N = 39, 7 groups), prednisone (N = 5), or controls (N = 6). Samples were collected from baseline to week 10 after treatment, when pigs were euthanized and carefully dissected at necropsy. Antigen levels decreased proportionally to the efficacy of treatment and correlated with the remaining viable cysts at necropsy (Pearson's p = 0.67, P = 0.000). A decrease of 5 times in antigen levels (logarithmic scale) compared with baseline was found in 20/26 pigs free of cysts at necropsy, compared with 1/24 of those who had persisting viable cysts (odds ratio [OR] = 76.7, 95% confidence interval [CI] = 8.1–3308.6, P < 0.001). Antigen monitoring reflects the course of infection in the pig. If a similar correlation exists in infected humans, this assay may provide a minimally invasive and easy monitoring assay to assess disease evolution and efficacy of antiparasitic treatment in human neurocysticercosis. PMID:26392159

  11. Paradigm Shift in Dendritic Cell-Based Immunotherapy: From in vitro Generated Monocyte-Derived DCs to Naturally Circulating DC Subsets

    PubMed Central

    Wimmers, Florian; Schreibelt, Gerty; Sköld, Annette E.; Figdor, Carl G.; De Vries, I. Jolanda M.

    2014-01-01

    Dendritic cell (DC)-based immunotherapy employs the patients’ immune system to fight neoplastic lesions spread over the entire body. This makes it an important therapy option for patients suffering from metastatic melanoma, which is often resistant to chemotherapy. However, conventional cellular vaccination approaches, based on monocyte-derived DCs (moDCs), only achieved modest response rates despite continued optimization of various vaccination parameters. In addition, the generation of moDCs requires extensive ex vivo culturing conceivably hampering the immunogenicity of the vaccine. Recent studies, thus, focused on vaccines that make use of primary DCs. Though rare in the blood, these naturally circulating DCs can be readily isolated and activated thereby circumventing lengthy ex vivo culture periods. The first clinical trials not only showed increased survival rates but also the induction of diversified anti-cancer immune responses. Upcoming treatment paradigms aim to include several primary DC subsets in a single vaccine as pre-clinical studies identified synergistic effects between various antigen-presenting cells. PMID:24782868

  12. Successful Antiparasitic Treatment for Cysticercosis is Associated with a Fast and Marked Reduction of Circulating Antigen Levels in a Naturally Infected Pig Model.

    PubMed

    Gonzalez, Armando E; Bustos, Javier A; Garcia, Hector H; Rodriguez, Silvia; Zimic, Mirko; Castillo, Yesenia; Praet, Nicolas; Gabriël, Sarah; Gilman, Robert H; Dorny, Pierre

    2015-12-01

    Taenia solium cysticercosis is a common parasitic infection of humans and pigs. We evaluated the posttreatment evolution of circulating parasite-specific antigen titers in 693 consecutive blood samples from 50 naturally infected cysticercotic pigs, which received different regimes of antiparasitic drugs (N = 39, 7 groups), prednisone (N = 5), or controls (N = 6). Samples were collected from baseline to week 10 after treatment, when pigs were euthanized and carefully dissected at necropsy. Antigen levels decreased proportionally to the efficacy of treatment and correlated with the remaining viable cysts at necropsy (Pearson's p = 0.67, P = 0.000). A decrease of 5 times in antigen levels (logarithmic scale) compared with baseline was found in 20/26 pigs free of cysts at necropsy, compared with 1/24 of those who had persisting viable cysts (odds ratio [OR] = 76.7, 95% confidence interval [CI] = 8.1-3308.6, P < 0.001). Antigen monitoring reflects the course of infection in the pig. If a similar correlation exists in infected humans, this assay may provide a minimally invasive and easy monitoring assay to assess disease evolution and efficacy of antiparasitic treatment in human neurocysticercosis.

  13. Differential pathogenesis of lethal mousepox in congenic DBA/2 mice implicates natural killer cell receptor NKR-P1 in necrotizing hepatitis and the fifth component of complement in recruitment of circulating leukocytes to spleen.

    PubMed

    Brownstein, D G; Gras, L

    1997-04-01

    Innate resistance of C57BL/6 (B6) mice to lethal mousepox is controlled by multiple genes. Previously, four resistance genes were localized to specific subchromosomal regions and transferred onto a susceptible DBA/2 (D2) background by serial backcrossing and intercrossing to produce congenic strains. Intraperitoneally inoculated ectromelia virus was uniformly lethal and achieved similar titers in B6 and D2 mice but elicited differential responses in liver, spleen, and circulating blood leukocytes. The distribution of these response phenotypes in congenic strains linked control of phenotypes with specific subchromosomal regions. D2.R1 mice, which carried a differential segment of chromosome 6, exhibited a B6 liver response and intermediate spleen and circulating leukocyte responses. D2.R2 and D2.R4 mice, which carried differential segments of chromosomes 2 and 1, respectively, exhibited a D2 liver response, a B6 spleen response, and an intermediate circulating leukocyte response. The localization of control of liver response phenotypes to chromosome 6 implicates cells that express natural killer (NK) cell receptor NKR-P1 alloantigens. The localization of control of spleen and circulating leukocyte responses to chromosomes 1, 2, and 6 implicates NK cells, the fifth component of complement, and a gene near the selectin gene complex in recruitment of circulating leukocytes to spleen.

  14. Fetal Circulation

    MedlinePlus

    ... Echocardiography/Your Unborn Baby's Heart - Fetal Echocardiogram Test - Detection of a Heart Defect - Fetal Circulation • Care & Treatment • Tools & Resources Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Target Heart Rates 4 Heart Attack Symptoms in Women ...

  15. MELCOR 1.8.5 Simulation of TMI-2 Phase 2 With an Enhanced 2-Dimensional In-Vessel Natural Circulation Model

    SciTech Connect

    Gauntt, Randall O.; Ross, Kyle; Wagner, Kenneth

    2002-07-01

    Phase 2 of the TMI-2 accident (core uncover and melting) is revisited with the latest release of MELCOR (i.e., Version 1.8.5). An enhanced multi-ring multi-level hydro nodalization of the reactor core and upper plenum was developed to permit calculation of natural convection heat transfer between the core and upper internals. Uncertainties in boundary and initial conditions are investigated with particular attention given to the distribution of liquid in the RCS at the beginning of Phase 2 and to the histories of pressure and level in the steam generators. Special attention given to modeling the boiler sides of the once-through steam generators is presented. The modeling is designed to capture the rapid condensation of RCS vapor that would result from spraying cold auxiliary feedwater directly onto the upper portion of a voided steam generator tube bundle. Presentation of key Phase-2 accident signatures including fuel temperatures and hydrogen generation are presented. Comparisons are made between MELCOR calculations, TMI-2 data, and SCDAP/RELAP simulations. A largely improved MELCOR simulation of TMI-2 Phase 2 is obtained. (authors)

  16. TROPICAL METEOROLOGY & Climate: Hadley Circulation

    SciTech Connect

    Lu, Jian; Vecchi, Gabriel A.

    2015-01-30

    The Hadley circulation, a prominent circulation feature characterized by rising air near the Equator and sinking air in the subtropics, defines the position of dry subtropical areas and is a fundamental regulator of the earth’s energy and momentum budgets. The character of the Hadley circulation, and its related precipitation regimes, exhibits variation and change in response to both climate variability and radiative forcing changes. The strength and position of the Hadley circulation change from year to year paced by El Niño and La Niña events. Over the last few decades of the twentieth century, the Hadley cell has expanded poleward in both hemispheres, with changes in atmospheric composition (including stratospheric ozone depletion and greenhouse gas increases) thought to have contributed to its expansion. This article introduces the basic phenomenology and driving mechanism of the Hadley circulation and discusses its variations under both natural and anthropogenic climate forcings.

  17. National Stormwater Calculator: A desktop tool that helps users control runoff to promote the natural movement of water

    EPA Science Inventory

    The primary focus of the National Stormwater Calculator (SWC) is to inform site developers on how well they can meet a desired stormwater retention target, but it can also be used by landscapers and homeowners. The SWC shows users how land use decisions and low impact development...

  18. Analytic energy derivatives for the calculation of the first-order molecular properties using the domain-based local pair-natural orbital coupled-cluster theory

    NASA Astrophysics Data System (ADS)

    Datta, Dipayan; Kossmann, Simone; Neese, Frank

    2016-09-01

    The domain-based local pair-natural orbital coupled-cluster (DLPNO-CC) theory has recently emerged as an efficient and powerful quantum-chemical method for the calculation of energies of molecules comprised of several hundred atoms. It has been demonstrated that the DLPNO-CC approach attains the accuracy of a standard canonical coupled-cluster calculation to about 99.9% of the basis set correlation energy while realizing linear scaling of the computational cost with respect to system size. This is achieved by combining (a) localized occupied orbitals, (b) large virtual orbital correlation domains spanned by the projected atomic orbitals (PAOs), and (c) compaction of the virtual space through a truncated pair natural orbital (PNO) basis. In this paper, we report on the implementation of an analytic scheme for the calculation of the first derivatives of the DLPNO-CC energy for basis set independent perturbations within the singles and doubles approximation (DLPNO-CCSD) for closed-shell molecules. Perturbation-independent one-particle density matrices have been implemented in order to account for the response of the CC wave function to the external perturbation. Orbital-relaxation effects due to external perturbation are not taken into account in the current implementation. We investigate in detail the dependence of the computed first-order electrical properties (e.g., dipole moment) on the three major truncation parameters used in a DLPNO-CC calculation, namely, the natural orbital occupation number cutoff used for the construction of the PNOs, the weak electron-pair cutoff, and the domain size cutoff. No additional truncation parameter has been introduced for property calculation. We present benchmark calculations on dipole moments for a set of 10 molecules consisting of 20-40 atoms. We demonstrate that 98%-99% accuracy relative to the canonical CCSD results can be consistently achieved in these calculations. However, this comes with the price of tightening the

  19. 40 CFR 230.23 - Current patterns and water circulation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Current patterns and water circulation... patterns and water circulation. (a) Current patterns and water circulation are the physical movements of water in the aquatic ecosystem. Currents and circulation respond to natural forces as modified by...

  20. 40 CFR 230.23 - Current patterns and water circulation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Current patterns and water circulation... patterns and water circulation. (a) Current patterns and water circulation are the physical movements of water in the aquatic ecosystem. Currents and circulation respond to natural forces as modified by...

  1. 40 CFR 230.23 - Current patterns and water circulation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Current patterns and water circulation... patterns and water circulation. (a) Current patterns and water circulation are the physical movements of water in the aquatic ecosystem. Currents and circulation respond to natural forces as modified by...

  2. 40 CFR 230.23 - Current patterns and water circulation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Current patterns and water circulation... patterns and water circulation. (a) Current patterns and water circulation are the physical movements of water in the aquatic ecosystem. Currents and circulation respond to natural forces as modified by...

  3. Determination of the absolute configuration of the natural product Klaivanolide via density functional calculations of vibrational circular dichroism (VCD).

    PubMed

    Devlin, Frank J; Stephens, Philip J; Figadère, Bruno

    2009-01-01

    The absolute configuration (AC) of the antiprotozoal lactone, Klaivanolide, 1, from Uvaria klaineana, has been determined using Vibrational Circular Dichroism (VCD) spectroscopy. The experimental VCD spectrum of the (+) enantiomer of 1 was measured. To analyze the AC of (+)-1, the conformationally-averaged VCD spectrum of 7-S-1 was calculated using density functional theory (DFT) and the GAUSSIAN 03 program. The B3PW91/TZ2P conformationally-averaged VCD spectrum of 7-S-1 proves that the AC of 1 is 7-S-(+).

  4. Circulating CD56dim natural killer cells and CD56+ T cells that produce interferon-γ or interleukin-10 are expanded in asymptomatic, E antigen-negative patients with persistent hepatitis B virus infection.

    PubMed

    Conroy, M J; Mac Nicholas, R; Grealy, R; Taylor, M; Otegbayo, J A; O'Dea, S; Mulcahy, F; Ryan, T; Norris, S; Doherty, D G

    2015-03-01

    Infection with hepatitis B virus (HBV) can result in spontaneous resolution or chronic infection, which can remain asymptomatic or can progress to cirrhosis and/or hepatocellular carcinoma. The host immune response is thought to be a major determinant of the outcome of HBV infection and virus-specific cytotoxic T lymphocytes (CTL) can mediate immunity against the virus and cause liver pathology. Antigen-nonspecific innate lymphocytes may also contribute to HBV infection and liver disease, therefore, we examined the frequencies, phenotypes, cytolytic activities and cytokine profiles of circulating natural killer (NK) cells, CD1d-restricted invariant natural killer T (iNKT) cells and CD56(+) T cells in 102 asymptomatic HBV-infected patients and compared them with those in 66 uninfected control subjects. NK cells expressing low levels of CD56 (CD56(dim)) and CD56(+) T cells were significantly expanded in the circulation of HBV-infected patients compared with control subjects. CD1d expression and iNKT cell frequencies were similar in both groups. Despite these expansions, we did not detect augmented natural or cytokine-induced cytotoxicity in the HBV-infected subjects. All lymphocyte populations studied produced interferon-γ (IFN-γ) significantly more frequently when taken from HBV-infected patients compared with when taken from healthy controls. Additionally, NK cells from the patients more frequently produced interleukin-10. As our HBV-infected cohort consisted of asymptomatic patients with low viral loads, we propose that CD56(dim) NK cells and CD56(+) T cells control HBV infection by noncytolytic mechanisms.

  5. Reconnaissance estimates of natural recharge to desert basins in Nevada, U.S.A., by using chloride-balance calculations

    USGS Publications Warehouse

    Dettinger, M.D.

    1989-01-01

    A chloride-balance method for estimating average natural recharge to groundwater basins in the Basin and Range Province of the western United States may be a useful alternative or complement to current techniques. The chloride-balance method, as presented in this paper, equates chloride in recharge water and runoff to chloride deposited in mountainous recharge-source areas by precipitation and dry fallout. Given estimates of annual precipitation on these source areas and chloride concentrations of bulk precipitation and recharge water, the rate of recharge can be estimated providing that: (1) no other major sources of chloride exist; (2) direct runoff to discharge areas in the basin is small or can otherwise be taken in account in the balance; and (3) the recharge sources for the basin are correctly delineated. The estimates are sensitive to the estimated rate of input of chloride from the atmosphere; this is the greatest data need for future applications of the method. Preliminary applications of the method to sixteen basins in Nevada, including Las Vegas Valley, indicate that the method can be a useful tool for hydrologists and resource managers. Correlation coefficients between recharge efficiencies for the basins - estimated on the basis of recharge estimates that use the chloride-balance method and two other currently used techniques - range from 0.54 to 0.95, depending on assumptions about where the method may be applied. ?? 1989.

  6. Observation of the thermosiphon effect in the circulation of liquid nitrogen in HTS cable cooling system

    NASA Astrophysics Data System (ADS)

    Ivanov, Yury; Watanabe, Hirofumi; Hamabe, Makoto; Kawahara, Toshio; Sun, Jian; Yamaguchi, Satarou

    It is traditionally considered that superconducting technology is just the way that will help to overcome the energy crisis and improve the environmental safety of the electricity production. However, real achievements in this field still insufficient to build commercial long power transmission lines. In particular, cooling systems constructed using expensive coolant circulation pumps have to be improved. Our previous calculations show that the use of a thermosiphon effect may reduce both the heat load and the required coolant circulation pump power and, ideally, would completely abandon the forced circulation. Direct experimental verification of this approach has been carried out at the new 200-meter HTS DC experimental facility of the Chubu University. The thermosiphon effect was clearly observed in satisfactory agreement with theory, although the change in elevation of the cryopipe was small. Our results will be used to design an effective HTS cable cooling system based on natural circulation of the coolant.

  7. The Nature of Metal-Metal Interactions in Dimeric Hydrides and Halides of Group 11 Elements in the Light of High Level Relativistic Calculations.

    PubMed

    Dem'yanov, Piotr I; Polestshuk, Pavel M; Kostin, Vladimir V

    2017-03-08

    The titular calculations show that charges at metal atoms M are apparently the main factor governing the nature of M⋅⋅⋅M interactions in two-nuclear coinage-metal complexes, and there are certain critical values of positive charges on M atoms, on exceeding which the pair-wise M⋅⋅⋅M interactions and/or the binding between M atoms in such complexes become repulsive despite negative formation energies of such complexes, short M-M internuclear distances, and the existence of a bond critical point (BCP) between M atoms.

  8. Dike Emplacement and Hydrothermal Circulation on Mars

    NASA Astrophysics Data System (ADS)

    Craft, K.; Lowell, R.; Germanovich, L.

    2010-03-01

    Using a finite element program, we model a dike propagating on Mars and calculate how the resulting surrounding stresses affect circulation in an adjacent porous medium. We also investigate the melting of an ice layer overlying the porous medium.

  9. Dispensing with the DVD Circulation Dilemma

    ERIC Educational Resources Information Center

    Ellis, Mark

    2008-01-01

    Richmond Public Library (RPL) is a four-branch suburban library with the highest per capita circulation of any comparable library in Canada. While DVDs naturally fit into RPL's emphasis on popular material, circulating them using the standard model proved problematic: Long hold queues built up, DVDs idled on the hold shelves, and the circulation…

  10. Circulation in blast driven instabilities

    NASA Astrophysics Data System (ADS)

    Henry de Frahan, Marc; Johnsen, Eric

    2016-11-01

    Mixing in many natural phenomena (e.g. supernova collapse) and engineering applications (e.g. inertial confinement fusion) is often initiated through hydrodynamic instabilities. Explosions in these systems give rise to blast waves which can interact with perturbations at interfaces between different fluids. Blast waves are formed by a shock followed by a rarefaction. This wave profile leads to complex time histories of interface acceleration. In addition to the instabilities induced by the acceleration field, the rarefaction from the blast wave decompresses the material at the interface, further increasing the perturbation growth. After the passage of the wave, circulation circulation generated by the blast wave through baroclinic vorticity continues to act upon the interface. In this talk, we provide scaling laws for the circulation and amplitude growth induced by the blast wave. Numerical simulations of the multifluid Euler equations solved using a high-order accurate Discontinuous Galerkin method are used to validate the theoretical results.

  11. Satellite Altimetry, Ocean Circulation, and Data Assimilation

    NASA Technical Reports Server (NTRS)

    Fu, Lee-Lueng

    1999-01-01

    Ocean circulation is a critical factor in determining the Earth's climate. Satellite altimetry has been proven a powerful technique for measuring the height of the sea surface for the study of global ocean circulation dynamics. A major objective of my research is to investigate the utility of altimeter data for ocean circulation studies. The 6 years' data record of TOPEX/POSEIDON have been analyzed to study the spatial and temporal characteristics of large-scale ocean variability. A major result obtained in 1998 is the discovery of large-scale oscillations in sea level with a period of 25 days in the Argentine Basin of the South Atlantic Ocean (see diagram). They exhibit a dipole pattern with counterclockwise rotational propagation around the Zapiola Rise (centered at 45S and 317E), a small seamount in the abyssal plain of the basin. The peak-to-trough amplitude is about 10 cm over a distance of 500-1000 km. The amplitude of these oscillations has large seasonal-to-interannual variations. The period and rotational characteristics of these oscillations are remarkably similar to the observations made by two current meters deployed near the ocean bottom in the region. What TOPEX/POSEIDON has detected apparently are manifestations of the movement of the entire water column (barotropic motion). The resultant transport variation is estimated to be about 50 x 10(exp 6) cubic M/S, which is about 50% of the total water transport in the region. Preliminary calculations suggest that these oscillations are topographically trapped waves. A numerical model of the South Atlantic is used to investigate the nature of and causes for these waves. A very important property of sea surface height is that it is directly related to the surface geostrophic velocity, which is related to deep ocean circulation through the density field. Therefore altimetry observations are not only useful for determining the surface circulation but also for revealing information about the deep ocean. Another

  12. Molecular structure, Normal Coordinate Analysis, harmonic vibrational frequencies, Natural Bond Orbital, TD-DFT calculations and biological activity analysis of antioxidant drug 7-hydroxycoumarin

    NASA Astrophysics Data System (ADS)

    Sebastian, S.; Sylvestre, S.; Jayarajan, D.; Amalanathan, M.; Oudayakumar, K.; Gnanapoongothai, T.; Jayavarthanan, T.

    2013-01-01

    In this work, we report harmonic vibrational frequencies, molecular structure, NBO and HOMO, LUMO analysis of Umbelliferone also known as 7-hydroxycoumarin (7HC). The optimized geometric bond lengths and bond angles obtained by computation (monomer and dimmer) shows good agreement with experimental XRD data. Harmonic frequencies of 7HC were determined and analyzed by DFT utilizing 6-311+G(d,p) as basis set. The assignments of the vibrational spectra have been carried out with the help of Normal Coordinate Analysis (NCA) following the Scaled Quantum Mechanical Force Field Methodology (SQMFF). The change in electron density (ED) in the σ* and π* antibonding orbitals and stabilization energies E(2) have been calculated by Natural Bond Orbital (NBO) analysis to give clear evidence of stabilization originating in the hyperconjugation of hydrogen-bonded interaction. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) complements with the experimental findings. The simulated spectra satisfactorily coincides with the experimental spectra. Microbial activity of studied compounds was tested against Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis, Escherichia coli, Psuedomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Shigella flexneri, Salmonella typhi and Enterococcus faecalis.

  13. Calculating the number of people with Alzheimer's disease in any country using saturated mutation models of brain cell loss that also predict widespread natural immunity to the disease.

    PubMed

    Kramer, Ivan

    2010-06-01

    The series of mutations that cause brain cells to spontaneously and randomly die leading to Alzheimer's disease (AD) is modelled. The prevalence of AD as a function of age in males and females is calculated from two very different mutation models of brain cell death. Once the prevalence functions are determined, the number of people with AD in any country or city can be estimated. The models developed here depend on three independent parameters: the number of mutations necessary for a brain cell associated with AD to spontaneously die, the average time between mutations, and the fraction of the risk population that is immune to developing the disease, if any. The values of these parameters are determined by fitting the model's AD incidence function to the incidence data. The best fits to the incidence rate data predict that as much as 74.1% of males and 79.5% of females may be naturally immune to developing AD. Thus, the development of AD is not a normal or inevitable result of the aging process. These fits also predict that males and females develop AD through different pathways, requiring a different number of mutations to cause the disease. The number of people in the USA with AD in the year 2000 is estimated to be 451,000. It is of paramount importance to determine the nature of the immunity to AD predicted here. Finding ways of blocking the mutations leading to the random, spontaneous death of memory brain cells would prevent AD from developing altogether.

  14. Isotopic constraints on the nature and circulation of deep mantle C-H-O-N fluids: Carbon and nitrogen systematics within ultra-deep diamonds from Kankan (Guinea)

    NASA Astrophysics Data System (ADS)

    Palot, M.; Pearson, D. G.; Stern, R. A.; Stachel, T.; Harris, J. W.

    2014-08-01

    their formation in the lower mantle by fluids that originate either from mantle or subducted carbon sources. A carbon flux from subducted oceanic lithospheric mantle may be important in the latter case. The strictly positive δ15N signatures found both in KK-200B (δ13C > 0‰) and KK-204 (δ13C slightly negative) illustrate that surficial carbon and nitrogen are potentially recycled as deep as the asthenosphere/transition zone and the lower mantle. Calculations of the diffusive relaxation of carbon isotope heterogeneity indicate that these ultra-deep diamonds may have a relatively young age and/or experienced rapid vertical movement to shallower mantle conditions, possibly by plume-related mantle.

  15. Circulating glioma biomarkers

    PubMed Central

    Kros, Johan M.; Mustafa, Dana M.; Dekker, Lennard J.M.; Sillevis Smitt, Peter A.E.; Luider, Theo M.; Zheng, Ping-Pin

    2015-01-01

    Validated biomarkers for patients suffering from gliomas are urgently needed for standardizing measurements of the effects of treatment in daily clinical practice and trials. Circulating body fluids offer easily accessible sources for such markers. This review highlights various categories of tumor-associated circulating biomarkers identified in blood and cerebrospinal fluid of glioma patients, including circulating tumor cells, exosomes, nucleic acids, proteins, and oncometabolites. The validation and potential clinical utility of these biomarkers is briefly discussed. Although many candidate circulating protein biomarkers were reported, none of these have reached the required validation to be introduced for clinical practice. Recent developments in tracing circulating tumor cells and their derivatives as exosomes and circulating nuclear acids may become more successful in providing useful biomarkers. It is to be expected that current technical developments will contribute to the finding and validation of circulating biomarkers. PMID:25253418

  16. Magnitude and nature of carbohydrate-aromatic interactions in fucose-phenol and fucose-indole complexes: CCSD(T) level interaction energy calculations.

    PubMed

    Tsuzuki, Seiji; Uchimaru, Tadafumi; Mikami, Masuhiro

    2011-10-20

    The CH/π contact structures of the fucose-phenol and fucose-indole complexes and the stabilization energies by formation of the complexes (E(form)) were studied by ab initio molecular orbital calculations. The three types of interactions (CH/π and OH/π interactions and OH/O hydrogen bonds) were compared and evaluated in a single molecular system and at the same level of theory. The E(form) calculated for the most stable CH/π contact structure of the fucose-phenol complex at the CCSD(T) level (-4.9 kcal/mol) is close to that for the most stable CH/π contact structure of the fucose-benzene complex (-4.5 kcal/mol). On the other hand the most stable CH/π contact structure of the fucose-indole complex has substantially larger E(form) (-6.5 kcal/mol). The dispersion interaction is the major source of the attraction in the CH/π contact structures of the fucose-phenol and fucose-indole complexes as in the case of the fucose-benzene complex. The electrostatic interactions in the CH/π contact structures are small (less than 1.5 kcal/mol). The nature of the interactions between the nonpolar surface of the carbohydrate and aromatic rings is completely different from that of the conventional hydrogen bonds where the electrostatic interaction is the major source of the attraction. The distributed multipole analysis and DFT-SATP analysis show that the dispersion interactions in the CH/π contact structure of fucose-indole complex are substantially larger than those in the CH/π contact structures of fucose-benzene and fucose-phenol complexes. The large dispersion interactions are responsible for the large E(form) for the fucose-indole complex.

  17. Coronary collateral circulation: its relevance.

    PubMed

    Karrowni, Wassef; El Accaoui, Ramzi N; Chatterjee, Kanu

    2013-11-15

    The interest in coronary collateral circulation (CCC) as "natural bypasses" is growing, especially in patients in whom the extent of coronary atherosclerosis is too severe to allow for conventional revascularization. The anatomic foundation of CCC has been recognized for long time. Recently, reliable methods have become available for the assessment of the adequacy of collateral flow. However, the debate regarding the importance of CCC in the different clinical settings continues. In this article, we present the recent progress in the understanding of anatomy and physiology of the CCC and focus on the studies addressing their functional significance in acute, subacute, and chronic coronary artery disease. In addition, we provide a focused update on the essential role of collateral circulation in the management of coronary chronic total occlusions.

  18. Circulation Systems on Microcomputers.

    ERIC Educational Resources Information Center

    Carlson, Gary

    1984-01-01

    Reports on the use of microcomputers in comprehensive library circulation systems. Topics covered include system requirements (reliability, completeness); determining circulation system needs (saving money, improving service, modernization); limitations of microcomputers (capacity, kinds of data stored, number of stations or terminals); system…

  19. Interannual variability of the Adriatic Sea circulation

    NASA Astrophysics Data System (ADS)

    Beg Paklar, Gordana; Sepic, Jadranka; Grbec, Branka; Dzoic, Tomislav; Kovac, Zarko; Ivatek-Sahdan, Stjepan

    2016-04-01

    The Regional Ocean Modeling System (ROMS) was implemented in order to reproduce interannual variability of the Adriatic Sea circulation. Simulations and model result analysis were performed for a three-year period from 1st January 2011 to 31st December 2013. ROMS model run was forced with realistic atmospheric fields obtained from meteorological model Aladin, climatological river discharges, tides and Mediterranean circulation imposed at the southern open boundary. Atmospheric forcing included momentum, heat and water fluxes calculated interactively from the Aladin surface fields during ROMS model simulations. Model results were compared with available CTD and ADCP measurements and discussed in the light of the climatological circulation and thermohaline properties of the Adriatic Sea and its coastal areas. Interannual variability in the Adriatic circulation is related to the prevailing atmospheric conditions, changes in the hydrological conditions and water mass exchange at the Otranto Strait. Basic features of the Adriatic circulation - basin-wide cyclonic circulation with several embedded smaller cyclonic gyres around main pits - are well reproduced by ROMS model. Modelled temperatures and salinities are within corresponding seasonal intervals, although measured profiles generally indicate stronger stratification than modelled ones. Summer circulation in 2011 with current reversal obtained along the eastern Adriatic coast was related to the sampling results of the early fish stages as well as to ARGO drifter movements. Simulated fields from the Adriatic scale model were used to prescribe the initial and open boundary conditions for the interannual simulation in the middle Adriatic coastal domain.

  20. Martian Atmospheric Circulation and Climate

    NASA Technical Reports Server (NTRS)

    Ingersoll, Andrew P.

    2003-01-01

    This proposal is focused on using Mars Global Surveyor (MGS) data and numerical models to address issues of atmospheric mixing of volatiles and aerosols, on defining the mean state of the atmosphere and the degree of variability, and on the processes which exchange volatiles and aerosols between the surface and atmosphere. Specifically, five areas of research were defined: In the first, we proposed to use TES data to examine the general circulation of the atmosphere both through retrieval of the residual circulation, and by comparison of the TES data with a Mars General Circulation Model (GCM). In the second, we proposed to look at synoptic and mesoscale atmospheric mixing processes (baroclinic storms, etc.) by combining TES and MOC Wide Angle data, and by employing a Mars Mesoscale Model. In the third section, we proposed to examine the record of the Martian atmospheric state provided by MGS, Viking, and Mariner 9 - as well as published ground-based observations - in order to assess the nature of interannual variability. In the forth section, we proposed to compare numerical models of the Martian water and dust cycles with TES and MOC data, specifically looking at water ice cloud distributions, dust distribution, etc. In the fifth section, we propose to use the mesoscale model to study the Mars Pathfinder Lander data. This work has now concluded its final of three years.

  1. Circulating serotonin in vertebrates.

    PubMed

    Maurer-Spurej, E

    2005-08-01

    The role of circulating serotonin is unclear and whether or not serotonin is present in the blood of non-mammalian species is not known. This study provides the first evidence for the presence of serotonin in thrombocytes of birds and three reptilian species, the endothermic leatherback sea turtle, the green sea turtle and the partially endothermic American alligator. Thrombocytes from a fresh water turtle, American bullfrog, Yellowfin tuna, and Chinook salmon did not contain serotonin. Serotonin is a vasoactive substance that regulates skin blood flow, a major mechanism for endothermic body temperature regulation, which could explain why circulating serotonin is present in warm-blooded species. The temperature sensitivity of human blood platelets with concomitant changes in serotonin content further supports a link between circulating serotonin and thermoregulation. Phylogenetic comparison of the presence of circulating serotonin indicated an evolutionary divergence within reptilian species that might coincide with the emergence of endothermy.

  2. Structural Determination of Circulation.

    ERIC Educational Resources Information Center

    Blankenburg, William B.

    1981-01-01

    Analyzes the effects of both structural factors (demographics, economic conditions, and competition) and discretionary factors (content, design, and marketing techniques) and concludes that it is the former that determine a newspaper's circulation. (FL)

  3. Computational chemistry of natural products: a comparison of the chemical reactivity of isonaringin calculated with the M06 family of density functionals.

    PubMed

    Glossman-Mitnik, Daniel

    2014-07-01

    The M06 family of density functionals has been assessed for the calculation of the molecular structure and properties of the Isonaringin flavonoid that can be an interesting material for dye-sensitized solar cells (DSSC). The chemical reactivity descriptors have been calculated through chemical reactivity theory within DFT (CR-DFT). The active sites for nucleophilic and electrophilic attacks have been chosen by relating them to the Fukui function indices and the dual descriptor f ((2))(r). A comparison between the descriptors calculated through vertical energy values and those arising from the Janak's theorem approximation have been performed in order to check for the validity of the last procedure.

  4. Ocean circulation using altimetry

    NASA Technical Reports Server (NTRS)

    Minster, Jean-Francois; Brossier, C.; Gennero, M. C.; Mazzega, P.; Remy, F.; Letraon, P. Y.; Blanc, F.

    1991-01-01

    Our group has been very actively involved in promoting satellite altimetry as a unique tool for observing ocean circulation and its variability. TOPEX/POSEIDON is particularly interesting as it is optimized for this purpose. It will probably be the first instrument really capable of observing the seasonal and interannual variability of subtropical and polar gyres and the first to eventually document the corresponding variability of their heat flux transport. The studies of these phenomena require data of the best quality, unbiased extraction of the signal, mixing of these satellite data with in situ measurements, and assimilation of the whole set into a dynamic description of ocean circulation. Our group intends to develop responses to all these requirements. We will concentrate mostly on the circulation of the South Atlantic and Indian Oceans: This will be done in close connection with other groups involved in the study of circulation of the tropical Atlantic Ocean, in the altimetry measurements (in particular, those of the tidal issue), and in the techniques of data assimilation in ocean circulation models.

  5. Towards clarifying the N-M vibrational nature of metallo-phthalocyanines. Infrared spectrum of phthalocyanine magnesium complex: density functional calculations.

    PubMed

    Zhang, Xianxi; Zhang, Yuexing; Jiang, Jianzhuang

    2004-08-01

    Infrared frequencies and intensities for the magnesium phthalocyanine complex MgPc have been calculated at density functional B3LYP level using the 6-31G(d) basis set. Detailed assignments of the metal-nitrogen (N-M) vibrational bands in the IR spectrum have been made on the basis of comparison of the calculated data of MgPc with the experimental result and also with that of H(2)Pc. The empirical controversial assignment of the characteristic band at 886-919 cm(-1) for metallo-phthalocyanines is also clearly interpreted. Nevertheless, the previous assignments of N-H stretchings, in-plane bending (IPB) and out-of-plane bending (OPB) modes made based on the comparative calculation of H(2)Pc and D(2)Pc are confirmed again by the present research result.

  6. On the North Atlantic circulation

    SciTech Connect

    Schmitz, W.J. Jr.; McCartney, M.S. )

    1993-02-01

    A summary for North Atlantic circulation is proposed to replace the circulation scheme hypothesized by Worthington in 1976. Divergences from the previous model are in thermohaline circulation, cross-equatorical transport and Florida Current sources, flow in the eastern Atlantic, circulation in the Newfoundland Basin, slope water currents, and flow pattern near the Bahamas. The circulation patterns presented here are consistent with the majority of of published accounts of flow components. 77 refs., 14 figs., 3 tabs.

  7. Transverse ageostrophic circulations associated with elevated mixed layers

    NASA Technical Reports Server (NTRS)

    Keyser, D.; Carlson, T. N.

    1984-01-01

    The nature of the frontogenetically forced transverse ageostrophic circulations connected with elevated mixed layer structure is investigated as a first step toward diagnosing the complex vertical circulation patterns occurring in the vicinity of elevated mixed layers within a severe storm environment. The Sawyer-Eliassen ageostrophic circulation equation is reviewed and applied to the elevated mixed layer detected in the SESAME IV data set at 2100 GMT of May 9, 1979. The results of the ageostrophic circulation diagnosis are confirmed and refined by considering an analytic specification for the elevated mixed layer structure.

  8. Ocean circulation modeling by use of radar altimeter data

    NASA Technical Reports Server (NTRS)

    Olbers, Dirk; Alpers, W.; Hasselmann, K.; Maier-Reimer, E.; Kase, R.; Krauss, W.; Siedler, G.; Willebrand, J.; Zahel, W.

    1991-01-01

    The project will investigate the use of radar altimetry (RA) data in the determination of the ocean circulation models. RA data will be used to verify prognostic experiments of the steady state and seasonal cycle of large-scale circulation models and the statistical steady state of eddy-resolving models. The data will serve as initial and update conditions in data assimilation experiments and as constraints in inverse calculations. The aim of the project is a better understanding of ocean physics, the determination and mapping of ocean currents, and a contribution to the establishment of ocean circulation models for climate studies. The goal of the project is to use satellite radar altimetry data for improving our knowledge of ocean circulation both in a descriptive sense and through the physics that govern the circulation state. The basic tool is a series of ocean circulation models. Depending on the model, different techniques will be applied to incorporate the RA data.

  9. Arctic circulation regimes.

    PubMed

    Proshutinsky, Andrey; Dukhovskoy, Dmitry; Timmermans, Mary-Louise; Krishfield, Richard; Bamber, Jonathan L

    2015-10-13

    Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability.

  10. Arctic circulation regimes

    PubMed Central

    Proshutinsky, Andrey; Dukhovskoy, Dmitry; Timmermans, Mary-Louise; Krishfield, Richard; Bamber, Jonathan L.

    2015-01-01

    Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability. PMID:26347536

  11. Portable oven air circulator

    DOEpatents

    Jorgensen, Jorgen A.; Nygren, Donald W.

    1983-01-01

    A portable air circulating apparatus for use in cooking ovens which is used to create air currents in the oven which transfer heat to cooking foodstuffs to promote more rapid and more uniform cooking or baking, the apparatus including a motor, fan blade and housing of metallic materials selected from a class of heat resistant materials.

  12. Bolus calculators.

    PubMed

    Schmidt, Signe; Nørgaard, Kirsten

    2014-09-01

    Matching meal insulin to carbohydrate intake, blood glucose, and activity level is recommended in type 1 diabetes management. Calculating an appropriate insulin bolus size several times per day is, however, challenging and resource demanding. Accordingly, there is a need for bolus calculators to support patients in insulin treatment decisions. Currently, bolus calculators are available integrated in insulin pumps, as stand-alone devices and in the form of software applications that can be downloaded to, for example, smartphones. Functionality and complexity of bolus calculators vary greatly, and the few handfuls of published bolus calculator studies are heterogeneous with regard to study design, intervention, duration, and outcome measures. Furthermore, many factors unrelated to the specific device affect outcomes from bolus calculator use and therefore bolus calculator study comparisons should be conducted cautiously. Despite these reservations, there seems to be increasing evidence that bolus calculators may improve glycemic control and treatment satisfaction in patients who use the devices actively and as intended.

  13. The aerodynamics of circulation control

    NASA Technical Reports Server (NTRS)

    Wood, N. J.

    1981-01-01

    Two dimensional subsonic wind tunnel tests were conducted on a 20% thickness: chord ratio circulation controlled elliptic aerofoil section equipped with forward and reverse blowing slots. Overall performance measurements were made over a range of trailing edge blowing momentum coefficients from 0 to 0.04; some included the effect of leading edge blowing. A detailed investigation of the trailing edge wall jet, using split film probes, hot wire probes and total head tubes, provided measurements of mean velocity components, Reynolds normal and shear stresses, and radial static pressure. The closure of the two dimensional angular momentum and continuity equations was examined using the measured data, with and without correction, and the difficulty of obtaining a satisfactory solution illustrated. Suggestions regarding the nature of the flow field which should aid the understanding of Coanda effect and the theoretical solution of highly curved wall jet flows are presented.

  14. A comparative Study of Circulation Patterns at Active Lava Lakes

    NASA Astrophysics Data System (ADS)

    Lev, Einat; Oppenheimer, Clive; Spampinato, Letizia; Hernandez, Pedro; Unglert, Kathi

    2016-04-01

    Lava lakes present a rare opportunity to study magma dynamics in a large scaled-up "crucible" and provide a unique natural laboratory to ground-truth dynamic models of magma circulation. The persistence of lava lakes allows for long-term observations of flow dynamics and of lava properties, especially compared to surface lava flows. There are currently five persistent lava lakes in the world: Halemaumau in Kilauea (Hawaii, USA), Erta Ale (Ethiopia), Nyiragongo (Congo), Erebus (Antarctica), and Villarica (Chile). Marum and Benbow craters of Ambrym volcano (Vanuatu) and Masaya (Nicaragua) have often hosted lava lakes as well. We use visible-light and thermal infrared time-lapse and video footage collected at all above lakes (except Villarica, where the lake is difficult to observe), and compare the circulation patterns recorded. We calculate lake surface motion from the footage using the optical flow method (Lev et al., 2012) to produce 2D velocity fields. We mined both the surface temperature field and the surface velocity field for patterns using machine learning techniques such as "self-organizing maps (SOMs)" and "principle component analysis (PCA)". We use automatic detection technique to study the configuration of crustal plates at the lakes' surface. We find striking differences among the lakes, in flow direction, flow speed, frequency of changes in flow direction and speed, location and consistency of upwelling and downwelling, and crustal plate configuration. We relate the differences to lake size, shallow conduit geometry, lava viscosity, crystal and gas content, and crust integrity.

  15. Numerical calculations of two dimensional, unsteady transonic flows with circulation

    NASA Technical Reports Server (NTRS)

    Beam, R. M.; Warming, R. F.

    1974-01-01

    The feasibility of obtaining two-dimensional, unsteady transonic aerodynamic data by numerically integrating the Euler equations is investigated. An explicit, third-order-accurate, noncentered, finite-difference scheme is used to compute unsteady flows about airfoils. Solutions for lifting and nonlifting airfoils are presented and compared with subsonic linear theory. The applicability and efficiency of the numerical indicial function method are outlined. Numerically computed subsonic and transonic oscillatory aerodynamic coefficients are presented and compared with those obtained from subsonic linear theory and transonic wind-tunnel data.

  16. The structure, energetics, and nature of the chemical bonding of phenylthiol adsorbed on the Au(111) surface: implications for density-functional calculations of molecular-electronic conduction.

    PubMed

    Bilić, Ante; Reimers, Jeffrey R; Hush, Noel S

    2005-03-01

    The adsorption of phenylthiol on the Au(111) surface is modeled using Perdew and Wang density-functional calculations. Both direct molecular physisorption and dissociative chemisorption via S-H bond cleavage are considered as well as dimerization to form disulfides. For the major observed product, the chemisorbed thiol, an extensive potential-energy surface is produced as a function of both the azimuthal orientation of the adsorbate and the linear translation of the adsorbate through the key fcc, hcp, bridge, and top binding sites. Key structures are characterized, the lowest-energy one being a broad minimum of tilted orientation ranging from the bridge structure halfway towards the fcc one. The vertically oriented threefold binding sites, often assumed to dominate molecular electronics measurements, are identified as transition states at low coverage but become favored in dense monolayers. A similar surface is also produced for chemisorption of phenylthiol on Ag(111); this displays significant qualitative differences, consistent with the qualitatively different observed structures for thiol chemisorption on Ag and Au. Full contours of the minimum potential energy as a function of sulfur translation over the crystal face are described, from which the barrier to diffusion is deduced to be 5.8 kcal mol(-1), indicating that the potential-energy surface has low corrugation. The calculated bond lengths, adsorbate charge and spin density, and the density of electronic states all indicate that, at all sulfur locations, the adsorbate can be regarded as a thiyl species that forms a net single covalent bond to the surface of strength 31 kcal mol(-1). No detectable thiolate character is predicted, however, contrary to experimental results for alkyl thiols that indicate up to 20%-30% thiolate involvement. This effect is attributed to the asymptotic-potential error of all modern density functionals that becomes manifest through a 3-4 eV error in the lineup of the adsorbate and

  17. A Method for Calculating the Heat Required for Windshield Thermal Ice Prevention Based on Extensive Flight Tests in Natural Icing Conditions

    NASA Technical Reports Server (NTRS)

    Jones, Alun R; Holdaway, George H; Steinmetz, Charles P

    1947-01-01

    An equation is presented for calculating the heat flow required from the surface of an internally heated windshield in order to prevent the formation of ice accretions during flight in specified icing conditions. To ascertain the validity of the equation, comparison is made between calculated values of the heat required and measured values obtained for test windshields in actual flights in icing conditions. The test windshields were internally heated and provided data applicable to two common types of windshield configurations; namely the V-type and the type installed flush with the fuselage contours. These windshields were installed on a twin-engine cargo airplane and the icing flights were conducted over a large area of the United States during the winters of 1945-46 and 1946-47. In addition to the internally heated windshield investigation, some test data were obtained for a windshield ice-prevention system in which heated air was discharged into the windshield boundary layer. The general conclusions resulting from this investigation are as follows: 1) The amount of heat required for the prevention of ice accretions on both flush- and V-type windshields during flight in specified icing conditions can be calculated with a degree of accuracy suitable for design purposes. 2) A heat flow of 2000 to 2500 Btu per hour per square foot is required for complete and continuous protection of a V-type windshield in fight at speeds up to 300 miles per hour in a moderate cumulus icing condition. For the same degree of protection and the same speed range, a value of 1000 Btu per hour per square foot suffices in a moderate stratus icing condition. 3) A heat supply of 1000 Btu per hour per square foot is adequate for a flush windshield located well aft of the fuselage stagnation region, at speeds up to 300 miles per hour, for flight in both stratus and moderate cumulus icing conditions. 4) The external air discharge system of windshield thermal ice prevention is thermally

  18. First step to investigate nature of electronic states and transport in flower-like MoS2: Combining experimental studies with computational calculations

    NASA Astrophysics Data System (ADS)

    Pandey, Kavita; Yadav, Pankaj; Singh, Deobrat; Gupta, Sanjeev K.; Sonvane, Yogesh; Lukačević, Igor; Kim, Joondong; Kumar, Manoj

    2016-09-01

    In the present paper, the nature of electronic states and transport properties of nanostructured flower-like molybdenum disulphide grown by hydrothermal route has been studied. The band structure, electronic nature of charge, thermodynamics and the limit of phonon scattering through density functional theory (DFT) has also been studied. The band tail states, dynamics of trap states and transport of carriers was investigated through intensive impedance spectroscopy analysis. The direct fingerprint of density and band tail state is analyzed from the capacitance plot as capacitance reflects the capability of a semiconductor to accept or release the charge carriers with a corresponding change in its Fermi potential levels. A recently introduced infrared photo-carrier radiometry and density functional perturbation theory (DFPT) techniques have been used to determine the temperature dependence of carrier mobility in flower type-MoS2. The present study illustrates that a large amount of trapped charges leads to an underestimation of the measured effective mobility and the potential of the material. Thus, a continuous engineering effort is required to improve the quality of fabricated nanostructures for its potential applications.

  19. First step to investigate nature of electronic states and transport in flower-like MoS2: Combining experimental studies with computational calculations

    PubMed Central

    Pandey, Kavita; Yadav, Pankaj; Singh, Deobrat; Gupta, Sanjeev K.; Sonvane, Yogesh; Lukačević, Igor; Kim, Joondong; Kumar, Manoj

    2016-01-01

    In the present paper, the nature of electronic states and transport properties of nanostructured flower-like molybdenum disulphide grown by hydrothermal route has been studied. The band structure, electronic nature of charge, thermodynamics and the limit of phonon scattering through density functional theory (DFT) has also been studied. The band tail states, dynamics of trap states and transport of carriers was investigated through intensive impedance spectroscopy analysis. The direct fingerprint of density and band tail state is analyzed from the capacitance plot as capacitance reflects the capability of a semiconductor to accept or release the charge carriers with a corresponding change in its Fermi potential levels. A recently introduced infrared photo-carrier radiometry and density functional perturbation theory (DFPT) techniques have been used to determine the temperature dependence of carrier mobility in flower type-MoS2. The present study illustrates that a large amount of trapped charges leads to an underestimation of the measured effective mobility and the potential of the material. Thus, a continuous engineering effort is required to improve the quality of fabricated nanostructures for its potential applications. PMID:27615369

  20. CARS spectroscopy of the NaH2 collision complex: the nature of the Na(32 P)H2 exciplex — ab initio calculations and experimental results

    NASA Astrophysics Data System (ADS)

    de Vivie-Riedle, R.; Hering, P.; Kompa, K. L.

    1990-12-01

    CARS (Coherent Anti-Stokes Raman Scattering) has been used to analyze the rovibronic state distribution of H2 after collision with Na(32 P). New lines, which do not correspond to H2 lines are observed in the CARS spectrum. The experiments point to the formation of a complex of Na(32 P)H2 in A 2 B 2 symmetry. Ab initio calculations of the A 2 B 2 potential were performed. On this surface the vibrational spectra of the exciplex are evaluated. The observed lines can be attributed to vibrational transitions in the complex, in which combinational modes are involved. The connection of experimental and theoretical results indicates that a collisionally stabilized exciplex molecule is formed during the quenching process.

  1. Lost circulation in geothermal wells: survey and evaluation of industry experience

    SciTech Connect

    Goodman, M.A.

    1981-07-01

    Lost circulation during drilling and completion of geothermal wells can be a severe problem, particularly in naturally fractured and/or vugular formations. Geothermal and petroleum operators, drilling service companies, and independent consultants were interviewed to assess the lost circulation problem in geothermal wells and to determine general practices for preventing lost circulation. This report documents the results and conclusions from the interviews and presents recommendations for needed research. In addition, a survey was also made of the lost circulation literature, of currently available lost circulation materials, and of existing lost circulation test equipment.

  2. Posterior Circulation Ischemic Stroke.

    PubMed

    Go, Steven

    2015-01-01

    Approximately 20-25% of all acute strokes occur in the posterior circulation. These strokes can be rather difficult to diagnose because they present in such diverse ways, and can easily be mistaken for more benign entities. A fastidious history, physical exam, high clinical suspicion, and appropriate use of imaging are essential for the emergency physician to properly diagnose and treat these patients. Expert stroke neurologist consultation should be utilized liberally.

  3. Ocean circulation studies

    NASA Technical Reports Server (NTRS)

    Koblinsky, C. J.

    1984-01-01

    Remotely sensed signatures of ocean surface characteristics from active and passive satellite-borne radiometers in conjunction with in situ data were utilized to examine the large scale, low frequency circulation of the world's oceans. Studies of the California Current, the Gulf of California, and the Kuroshio Extension Current in the western North Pacific were reviewed briefly. The importance of satellite oceanographic tools was emphasized.

  4. Learning Circulant Sensing Kernels

    DTIC Science & Technology

    2014-03-01

    Compressive sensing based high resolution channel estimation for OFDM system. To appear in IEEE Journal of Selected Topics in Signal Processing, Special...and R. D. Nowak. Toeplitz compressed sensing ma- trices with applications to sparse channel estimation . Submitted to IEEE Transactions on Information...various applications. For compressive sens- ing, recent work has used random Toeplitz and circulant sensing matrices and proved their efficiency in theory

  5. The fetal circulation.

    PubMed

    Kiserud, Torvid; Acharya, Ganesh

    2004-12-30

    Accumulating data on the human fetal circulation shows the similarity to the experimental animal physiology, but with important differences. The human fetus seems to circulate less blood through the placenta, shunt less through the ductus venosus and foramen ovale, but direct more blood through the lungs than the fetal sheep. However, there are substantial individual variations and the pattern changes with gestational age. The normalised umbilical blood flow decreases with gestational age, and, at 28 to 32 weeks, a new level of development seems to be reached. At this stage, the shunting through the ductus venosus and the foramen ovale reaches a minimum, and the flow through the lungs a maximum. The ductus venosus and foramen ovale are functionally closely related and represent an important distributional unit for the venous return. The left portal branch represents a venous watershed, and, similarly, the isthmus aorta an arterial watershed. Thus, the fetal central circulation is a very flexible and adaptive circulatory system. The responses to increased afterload, hypoxaemia and acidaemia in the human fetus are equivalent to those found in animal studies: increased ductus venosus and foramen ovale shunting, increased impedance in the lungs, reduced impedance in the brain, increasingly reversed flow in the aortic isthmus and a more prominent coronary blood flow.

  6. Transients in a circulating fluidized bed boiler

    NASA Astrophysics Data System (ADS)

    Baskakov, A. P.; Munts, V. A.; Pavlyuk, E. Yu.

    2013-11-01

    Transients in a circulating fluidized bed boiler firing biomass are considered. An attempt is made to describe transients with the use of concepts applied in the automatic control theory. The parameters calculated from an analysis of unsteady heat balance equations are compared with the experimental data obtained in the 12-MW boiler of the Chalmers University of Technology. It is demonstrated that these equations describe the transient modes of operation with good accuracy. Dependences for calculating the time constants of unsteady processes are obtained.

  7. General circulation of the ocean

    SciTech Connect

    Abarbanel, H.D.I.; Young, W.R.

    1986-01-01

    This book is an analysis of the geophysics of ocean circulation and its interaction with the atmosphere. It reviews the new concepts and models which have emerged in the last five years, as well as classical theories and observations. The contributions cover topics such as: the observational basis for large-scale circulation, including surface and deep circulation and subtropical gyres; thermocline theories; inverse methods for ocean circulation; baroclinic theories of the wind-driven circulation; and single layer models. This volume sets the current research literature in context, and suggests promising avenues for future study.

  8. The lens circulation.

    PubMed

    Mathias, Richard T; Kistler, Joerg; Donaldson, Paul

    2007-03-01

    The lens is the largest organ in the body that lacks a vasculature. The reason is simple: blood vessels scatter and absorb light while the physiological role of the lens is to be transparent so it can assist the cornea in focusing light on the retina. We hypothesize this lack of blood supply has led the lens to evolve an internal circulation of ions that is coupled to fluid movement, thus creating an internal micro-circulatory system, which makes up for the lack of vasculature. This review covers the membrane transport systems that are believed to generate and direct this internal circulatory system.

  9. World Ocean Circulation Experiment

    NASA Technical Reports Server (NTRS)

    Clarke, R. Allyn

    1992-01-01

    The oceans are an equal partner with the atmosphere in the global climate system. The World Ocean Circulation Experiment is presently being implemented to improve ocean models that are useful for climate prediction both by encouraging more model development but more importantly by providing quality data sets that can be used to force or to validate such models. WOCE is the first oceanographic experiment that plans to generate and to use multiparameter global ocean data sets. In order for WOCE to succeed, oceanographers must establish and learn to use more effective methods of assembling, quality controlling, manipulating and distributing oceanographic data.

  10. Walker circulation in a transient climate

    NASA Astrophysics Data System (ADS)

    Plesca, Elina; Grützun, Verena; Buehler, Stefan A.

    2016-04-01

    response (temperature change by the time of CO2 doubling), which in turn might be related to a decreased ocean heat uptake. This uncertainty across the models we attribute to the multitude of factors controlling ocean and atmosphere heat exchange, both at global and regional scales, as well as to the present capabilities of GCMs in simulating this exchange. References: England, M. H., McGregor, S., Spence, P., Meehl, G. A., Timmermann, A., Cai, W., Gupta, A. S., McPhaden, M. J., Purich, A., and Santoso, A., 2014. Recent intensification of wind-driven circulation in the Pacific and the ongoing warming hiatus. Nature Climate Change 4 (3): 222-227. Ma, J., and Xie, S. P., 2013. Regional Patterns of Sea Surface Temperature Change: A Source of Uncertainty in Future Projections of Precipitation and Atmospheric Circulation*. Journal of Climate, 26 (8): 2482-2501

  11. Circulation of Stars

    NASA Astrophysics Data System (ADS)

    Boitani, P.

    2016-01-01

    Since the dawn of man, contemplation of the stars has been a primary impulse in human beings, who proliferated their knowledge of the stars all over the world. Aristotle sees this as the product of primeval and perennial “wonder” which gives rise to what we call science, philosophy, and poetry. Astronomy, astrology, and star art (painting, architecture, literature, and music) go hand in hand through millennia in all cultures of the planet (and all use catasterisms to explain certain phenomena). Some of these developments are independent of each other, i.e., they take place in one culture independently of others. Some, on the other hand, are the product of the “circulation of stars.” There are two ways of looking at this. One seeks out forms, the other concentrates on the passing of specific lore from one area to another through time. The former relies on archetypes (for instance, with catasterism), the latter constitutes a historical process. In this paper I present some of the surprising ways in which the circulation of stars has occurred—from East to West, from East to the Far East, and from West to East, at times simultaneously.

  12. Fe Mg diffusion in olivine II: point defect chemistry, change of diffusion mechanisms and a model for calculation of diffusion coefficients in natural olivine

    NASA Astrophysics Data System (ADS)

    Dohmen, Ralf; Chakraborty, Sumit

    2007-08-01

    Analysis of existing data and models on point defects in pure (Fe,Mg)-olivine (Phys Chem Miner 10:27 37,1983; Phys Chem Miner 29:680 694, 2002) shows that it is necessary to consider thermodynamic non-ideality of mixing to adequately describe the concentration of point defects over the range of measurement. In spite of different sources of uncertainties, the concentrations of vacancies in octahedral sites in (Fe,Mg)-olivine are on the order of 10-4 per atomic formula unit at 1,000 1,200 °C according to both the studies. We provide the first explicit plots of vacancy concentrations in olivine as a function of temperature and oxygen fugacity according to the two models. It is found that in contrast to absolute concentrations at ˜1,100 °C and dependence on fO2, there is considerable uncertainty in our knowledge of temperature dependence of vacancy concentrations. This needs to be considered in discussing the transport properties such as diffusion coefficients. Moreover, these defect models in pure (Fe,Mg)-olivine need to be extended by considering aliovalent impurities such as Al, Cr to describe the behavior of natural olivine. We have developed such a formulation, and used it to analyze the considerable database of diffusion coefficients in olivine from Dohmen et al. (Phys Chem Miner this volume, 2007) (Part - I) and older data in the literature. The analysis documents unequivocally for the first time a change of diffusion mechanism in a silicate mineral—from the transition metal extrinsic (TaMED) to the purely extrinsic (PED) domain, at fO2 below 10-10 Pa, and consequently, temperatures below 900 °C. The change of diffusion mechanism manifests itself in a change in fO2 dependence of diffusivity and a slight change in activation energy of diffusion—the activation energy increases at lower temperatures. These are consistent with the predictions of Chakraborty (J Geophys Res 102(B6):12317 12331, 1997). Defect formation enthalpies in the TaMED regime (distinct

  13. Circulating Biomarkers in Bladder Cancer

    PubMed Central

    Nandagopal, Lakshminarayanan; Sonpavde, Guru

    2016-01-01

    Bladder cancer is a molecularly heterogeneous disease characterized by multiple unmet needs in the realm of diagnosis, clinical staging, monitoring and therapy. There is an urgent need to develop precision medicine for advanced urothelial carcinoma. Given the difficulty of serial analyses of metastatic tumor tissue to identify resistance and new therapeutic targets, development of non-invasive monitoring using circulating molecular biomarkers is critically important. Although the development of circulating biomarkers for the management of bladder cancer is in its infancy and may currently suffer from lower sensitivity of detection, they have inherent advantages owing to non-invasiveness. Additionally, circulating molecular alterations may capture tumor heterogeneity without the sampling bias of tissue biopsy. This review describes the accumulating data to support further development of circulating biomarkers including circulating tumor cells, cell-free circulating tumor (ct)-DNA, RNA, micro-RNA and proteomics to improve the management of bladder cancer. PMID:28035318

  14. Lost Circulation Technology Development Status

    SciTech Connect

    Glowka, David A.; Schafer, Diane M.; Loeppke, Glen E.; Scott, Douglas D.; Wernig, Marcus D.; Wright, Elton K.

    1992-03-24

    Lost circulation is the loss of drilling fluid from the wellbore to fractures or pores in the rock formation. In geothermal drilling, lost circulation is often a serious problem that contributes greatly to the cost of the average geothermal well. The Lost Circulation Technology Development Program is sponsored at Sandia National Laboratories by the U.S. Department of Energy. The goal of the program is to reduce lost circulation costs by 30-50% through the development of mitigation and characterization technology. This paper describes the technical progress made in this program during the period April, 1991-March, 1992.

  15. Global ocean circulation by altimetry

    NASA Technical Reports Server (NTRS)

    Wunsch, Carl; Haidvogel, D.

    1991-01-01

    The overall objectives of this project are to determine the general circulation of the oceans and many of its climate and biochemical consequences through the optimum use of altimetry data from TOPEX/POSEIDON and related missions. Emphasis is on the global-scale circulation, as opposed to the regional scale, but some more local studies will be carried out. Because of funding limitations, the primary initial focus will be on the time-dependent global-scale circulation rather than the mean; eventually, the mean circulation must be dealt with as well.

  16. Ocean General Circulation Models

    SciTech Connect

    Yoon, Jin-Ho; Ma, Po-Lun

    2012-09-30

    1. Definition of Subject The purpose of this text is to provide an introduction to aspects of oceanic general circulation models (OGCMs), an important component of Climate System or Earth System Model (ESM). The role of the ocean in ESMs is described in Chapter XX (EDITOR: PLEASE FIND THE COUPLED CLIMATE or EARTH SYSTEM MODELING CHAPTERS). The emerging need for understanding the Earth’s climate system and especially projecting its future evolution has encouraged scientists to explore the dynamical, physical, and biogeochemical processes in the ocean. Understanding the role of these processes in the climate system is an interesting and challenging scientific subject. For example, a research question how much extra heat or CO2 generated by anthropogenic activities can be stored in the deep ocean is not only scientifically interesting but also important in projecting future climate of the earth. Thus, OGCMs have been developed and applied to investigate the various oceanic processes and their role in the climate system.

  17. PULMONARY CIRCULATION AT EXERCISE

    PubMed Central

    NAEIJE, R; CHESLER, N

    2012-01-01

    The pulmonary circulation is a high flow and low pressure circuit, with an average resistance of 1 mmHg.min.L−1 in young adults, increasing to 2.5 mmHg.min.L−1 over 4–6 decades of life. Pulmonary vascular mechanics at exercise are best described by distensible models. Exercise does not appear to affect the time constant of the pulmonary circulation or the longitudinal distribution of resistances. Very high flows are associated with high capillary pressures, up to a 20–25 mmHg threshold associated with interstitial lung edema and altered ventilation/perfusion relationships. Pulmonary artery pressures of 40–50 mmHg, which can be achieved at maximal exercise, may correspond to the extreme of tolerable right ventricular afterload. Distension of capillaries that decrease resistance may be of adaptative value during exercise, but this is limited by hypoxemia from altered diffusion/perfusion relationships. Exercise in hypoxia is associated with higher pulmonary vascular pressures and lower maximal cardiac output, with increased likelihood of right ventricular function limitation and altered gas exchange by interstitial lung edema. Pharmacological interventions aimed at the reduction of pulmonary vascular tone have little effect on pulmonary vascular pressure-flow relationships in normoxia, but may decrease resistance in hypoxia, unloading the right ventricle and thereby improving exercise capacity. Exercise in patients with pulmonary hypertension is associated with sharp increases in pulmonary artery pressure and a right ventricular limitation of aerobic capacity. Exercise stress testing to determine multipoint pulmonary vascular pressures-flow relationships may uncover early stage pulmonary vascular disease. PMID:23105961

  18. Atmospheric Circulation of Exoplanets

    NASA Astrophysics Data System (ADS)

    Showman, A. P.; Cho, J. Y.-K.; Menou, K.

    2010-12-01

    We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize fundamental principles and insights gained from solar system studies that are likely to be generalizable to exoplanets. We begin by presenting the hierarchy of basic equations used in atmospheric dynamics, including the Navier-Stokes, primitive, shallow-water, and two-dimensional nondivergent models. We then survey key concepts in atmospheric dynamics, including the importance of planetary rotation, the concept of balance, and simple scaling arguments to show how turbulent interactions generally produce large-scale east-west banding on rotating planets. We next turn to issues specific to giant planets, including their expected interior and atmospheric thermal structures, the implications for their wind patterns, and mechanisms to pump their east-west jets. Hot Jupiter atmospheric dynamics are given particular attention, as these close-in planets have been the subject of most of the concrete developments in the study of exoplanetary atmospheres. We then turn to the basic elements of circulation on terrestrial planets as inferred from solar system studies, including Hadley cells, jet streams, processes that govern the large-scale horizontal temperature contrasts, and climate, and we discuss how these insights may apply to terrestrial exoplanets. Although exoplanets surely possess a greater diversity of circulation regimes than seen on the planets in our solar system, our guiding philosophy is that the multidecade study of solar system planets reviewed here provides a foundation upon which our understanding of more exotic exoplanetary meteorology must build.

  19. Circulating tumor cells

    PubMed Central

    Raimondi, Cristina; Nicolazzo, Chiara; Gradilone, Angela; Giannini, Giuseppe; De Falco, Elena; Chimenti, Isotta; Varriale, Elisa; Hauch, Siegfried; Plappert, Linda; Cortesi, Enrico; Gazzaniga, Paola

    2014-01-01

    The hypothesis of the “liquid biopsy” using circulating tumor cells (CTCs) emerged as a minimally invasive alternative to traditional tissue biopsy to determine cancer therapy. Discordance for biomarkers expression between primary tumor tissue and circulating tumor cells (CTCs) has been widely reported, thus rendering the biological characterization of CTCs an attractive tool for biomarkers assessment and treatment selection. Studies performed in metastatic colorectal cancer (mCRC) patients using CellSearch, the only FDA-cleared test for CTCs assessment, demonstrated a much lower yield of CTCs in this tumor type compared with breast and prostate cancer, both at baseline and during the course of treatment. Thus, although attractive, the possibility to use CTCs as therapy-related biomarker for colorectal cancer patients is still limited by a number of technical issues mainly due to the low sensitivity of the CellSearch method. In the present study we found a significant discordance between CellSearch and AdnaTest in the detection of CTCs from mCRC patients. We then investigated KRAS pathway activating mutations in CTCs and determined the degree of heterogeneity for KRAS oncogenic mutations between CTCs and tumor tissues. Whether KRAS gene amplification may represent an alternative pathway responsible for KRAS activation was further explored. KRAS gene amplification emerged as a functionally equivalent and mutually exclusive mechanism of KRAS pathway activation in CTCs, possibly related to transcriptional activation. The serial assessment of CTCs may represent an early biomarker of treatment response, able to overcome the intrinsic limit of current molecular biomarkers represented by intratumor heterogeneity. PMID:24521660

  20. Pulmonary circulation at exercise.

    PubMed

    Naeije, Robert; Chesler, N

    2012-01-01

    The pulmonary circulation is a high-flow and low-pressure circuit, with an average resistance of 1 mmHg/min/L in young adults, increasing to 2.5 mmHg/min/L over four to six decades of life. Pulmonary vascular mechanics at exercise are best described by distensible models. Exercise does not appear to affect the time constant of the pulmonary circulation or the longitudinal distribution of resistances. Very high flows are associated with high capillary pressures, up to a 20 to 25 mmHg threshold associated with interstitial lung edema and altered ventilation/perfusion relationships. Pulmonary artery pressures of 40 to 50 mmHg, which can be achieved at maximal exercise, may correspond to the extreme of tolerable right ventricular afterload. Distension of capillaries that decrease resistance may be of adaptative value during exercise, but this is limited by hypoxemia from altered diffusion/perfusion relationships. Exercise in hypoxia is associated with higher pulmonary vascular pressures and lower maximal cardiac output, with increased likelihood of right ventricular function limitation and altered gas exchange by interstitial lung edema. Pharmacological interventions aimed at the reduction of pulmonary vascular tone have little effect on pulmonary vascular pressure-flow relationships in normoxia, but may decrease resistance in hypoxia, unloading the right ventricle and thereby improving exercise capacity. Exercise in patients with pulmonary hypertension is associated with sharp increases in pulmonary artery pressure and a right ventricular limitation of aerobic capacity. Exercise stress testing to determine multipoint pulmonary vascular pressures-flow relationships may uncover early stage pulmonary vascular disease.

  1. Does Hydrothermal Circulation Matter?

    NASA Astrophysics Data System (ADS)

    Stein, C. A.; Stein, S.; von Herzen, R. P.; Fisher, A. T.

    2006-05-01

    Determining Earth's energy budget and the sources and mechanisms for heat transfer within it depends largely on assumptions of the heat loss from the formation and cooling of oceanic lithosphere, which covers about 60% of Earth's surface. Recently Hofmeister and Criss (2005) have suggested that the total global heat flow is about 30 TW, about 25% less than previously estimated by Pollack et al. (1993). The main difference between the two estimates is whether the effects of heat transfer by hydrothermal circulation are included. Thermal models describe the evolution of the lithosphere by the conductive cooling of hot material as it moves away from spreading centers. The frequently used half-space (boundary layer) and "plate" models generally successfully represent heat flow, depth, and geoid values with age, and depth-dependent properties such as flexural thickness, maximum depth of intraplate earthquakes, and lithospheric thickness. However, such models overpredict the measured heat flow from ridge crest to about 65 Myr crust. This difference is generally assumed to reflect water flow in the crust transporting heat, as shown by the spectacular hot springs at midocean ridges. If so, the observed heat flow is lower than the model's predictions, which assume that all heat is transferred by conduction. Because hydrothermal heat transport is hard to quantify, heat flow is about 50% larger than directly measured. This estimate is consistent with observations of hydrothermal circulation which indicate that the discrepancy is largely a result of the water fluxing along the oceanic basement and upwelling at isolated basement highs and outcrops. Detailed studies at such areas often show high heat flow near these outcrops and low heat flow in the surrounding areas. Hence isolated measurements are biased towards lower values and underpredict the total heat flow.

  2. Greenland Meltwater and Arctic Circulation Regimes

    NASA Astrophysics Data System (ADS)

    Dukhovskoy, D. S.; Proshutinsky, A. Y.; Timmermans, M. L.; Myers, P. G.; Platov, G.

    2015-12-01

    Between 1948 and 1996, wind-driven components of ice drift and surface ocean currents experienced a well-pronounced decadal variability alternating between anticyclonic and cyclonic circulation regimes. During cyclonic regimes, low sea level atmospheric pressure dominated over the Arctic Ocean driving sea ice and the upper ocean clockwise; the Arctic atmosphere was relatively warm and humid and freshwater flux from the Arctic Ocean toward the sub-Arctic seas was intensified. During anticylonic circulation regimes, high sea level pressure dominated over the Arctic driving sea ice and ocean counter-clockwise; the atmosphere was cold and dry and the freshwater flux from the Arctic to the sub-Arctic seas was reduced. Since 1997, however, the Arctic system has been dominated by an anticyclonic circulation regime with a set of environmental parameters that are atypical for these regimes. Of essential importance is to discern the causes and consequences of the apparent break-down in the natural decadal variability of the Arctic climate system, and specifically: Why has the well-pronounced decadal variability observed in the 20th century been replaced by relatively weak interannual changes under anticyclonic circulation regime conditions in the 21st century? We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from Greenland impact environmental conditions and interrupt their decadal variability. In order to test this hypothesis, numerical experiments with several FAMOS (Forum for Arctic Modeling & Observational Synthesis) ice-ocean coupled models have been conducted. In these experiments, Greenland melt freshwater is tracked by passive tracers being constantly released along the Greenland coast. Propagation pathways and time scales of Greenland meltwater within the sub-Arctic seas are discussed.

  3. Firewood calculator

    SciTech Connect

    Clark, A.; Curtis, A.B.; Darwin, W.N.

    1981-01-01

    Rotating cardboard discs are used to read off total tree or topwood firewood volume (tons or cords) that can be expected from trees of d.b.h. 6 to 24 inches and tree height 10 to 90 feet. One side of the calculator is used for broadleaved species with deliquescent crowns and the other side for braodleaves with excurrent crowns.

  4. Results of theoretical and experimental studies of hydrodynamics of circulation loops in circulating fluidized bed reactors and systems with interconnected reactors

    NASA Astrophysics Data System (ADS)

    Ryabov, G. A.; Folomeev, O. M.; Sankin, D. A.; Melnikov, D. A.

    2015-02-01

    Problems of the calculation of circulation loops in circulating fluidized bed reactors and systems with interconnected reactors (polygeneration systems for the production of electricity, heat, and useful products and chemical cycles of combustion and gasification of solid fuels)are considered. A method has been developed for the calculation of circulation loop of fuel particles with respect to boilers with circulating fluidized bed (CFB) and systems with interconnected reactors with fluidized bed (FB) and CFB. New dependences for the connection between the fluidizing agent flow (air, gas, and steam) and performance of reactors and for the whole system (solids flow rate, furnace and cyclone pressure drops, and bed level in the riser) are important elements of this method. Experimental studies of hydrodynamics of circulation loops on the aerodynamic unit have been conducted. Experimental values of pressure drop of the horizontal part of the L-valve, which satisfy the calculated dependence, have been obtained.

  5. Current detection technologies for circulating tumor cells.

    PubMed

    Shen, Zheyu; Wu, Aiguo; Chen, Xiaoyuan

    2017-04-10

    Circulating tumor cells (CTCs) are cancer cells that circulate in the blood stream after being naturally shed from original or metastatic tumors, and can lead to a new fatal metastasis. CTCs have become a hotspot research field during the last decade. Detection of CTCs, as a liquid biopsy of tumors, can be used for early diagnosis of cancers, earlier evaluation of cancer recurrence and chemotherapeutic efficacy, and choice of individual sensitive anti-cancer drugs. Therefore, CTC detection is a crucial tool to fight against cancer. Herein, we classify the currently reported CTC detection technologies, introduce some representative samples for each technology, conclude the advantages and limitations, and give a future perspective including the challenges and opportunities of CTC detection.

  6. Constraining the North Atlantic circulation with tritium data

    NASA Technical Reports Server (NTRS)

    Memery, Laurent; Wunsch, Carl

    1990-01-01

    The North Atlantic circulation derived from an inverse calculation by singular-value decomposition is tested against the historical record of tritium. A forward calculation of the tritium transient is performed using the circulation model, published estimates of atmospheric injection rates, and plausible estimates of the tracer history at the open boundaries of the model. The results do not agree with observations of the interior distributions of tritium. Consideration is given to the possibility of improving the agreement by modifying the atmospheric injection rates and the initial estimates of open boundary time histories, treating the boundary conditions as control variables.

  7. Definition of a generalized diabatic circulation based on a variational approach

    NASA Astrophysics Data System (ADS)

    Medvedev, A. S.

    2007-08-01

    Diabatic-circulation diagnostics with the use of the distributions of heating rates and potential temperature requires that, in each particular case, a special and ambiguously defined correction to the stream function be introduced to turn a globally averaged vertical velocity to zero at any isobaric level. Up to now, the physical nature of this correction has been little explained and it has been usually written in a form that has not been substantiated to a sufficient extent. In this paper, this correction and its uncertainty are related to the eddy term, which is usually neglected in the concept of diabatic velocities. The decomposition of wave fluxes into advective and diffusion components is not unique. As a result, one can formulate a variational problem of minimizing the diffusion component of the wave flux and, thus, the problem of finding advective velocities, which involve the maximum of eddy-induced advection. A unique solution of this problem is obtained, and the relation of the solution to the “standard” diabatic circulation is studied. It is shown that, in the approximation of quasi-horizontal isentropes, the generalized diabatic stream function is identical with the “standard“ stream function. This result partially justifies the correction that is commonly used in calculations of the diabatic circulation.

  8. Design Construction and Operation of a Supercritical Carbon Dioxide (sCO2) Loop for Investigation of Dry Cooling and Natural Circulation Potential for Use in Advanced Small Modular Reactors Utilizing sCO2 Power Conversion Cycles.

    SciTech Connect

    Middleton, Bobby D.; Rodriguez, Salvador B.; Carlson, Matthew David

    2015-11-01

    This report outlines the work completed for a Laboratory Directed Research and Development project at Sandia National Laboratories from October 2012 through September 2015. An experimental supercritical carbon dioxide (sCO 2 ) loop was designed, built, and o perated. The experimental work demonstrated that sCO 2 can be uti lized as the working fluid in an air - cooled, natural circulation configuration to transfer heat from a source to the ultimate heat sink, which is the surrounding ambient environment in most ca ses. The loop was also operated in an induction - heated, water - cooled configuration that allows for measurements of physical parameters that are difficult to isolate in the air - cooled configuration. Analysis included the development of two computational flu id dynamics models. Future work is anticipated to answer questions that were not covered in this project.

  9. Cosmological calculations on the GPU

    NASA Astrophysics Data System (ADS)

    Bard, D.; Bellis, M.; Allen, M. T.; Yepremyan, H.; Kratochvil, J. M.

    2013-02-01

    Cosmological measurements require the calculation of nontrivial quantities over large datasets. The next generation of survey telescopes will yield measurements of billions of galaxies. The scale of these datasets, and the nature of the calculations involved, make cosmological calculations ideal models for implementation on graphics processing units (GPUs). We consider two cosmological calculations, the two-point angular correlation function and the aperture mass statistic, and aim to improve the calculation time by constructing code for calculating them on the GPU. Using CUDA, we implement the two algorithms on the GPU and compare the calculation speeds to comparable code run on the CPU. We obtain a code speed-up of between 10 and 180× faster, compared to performing the same calculation on the CPU. The code has been made publicly available. GPUs are a useful tool for cosmological calculations, even for datasets the size of current surveys, allowing calculations to be made one or two orders of magnitude faster.

  10. Temperature field study of hot water circulation pump shaft system

    NASA Astrophysics Data System (ADS)

    Liu, Y. Y.; Kong, F. Y.; Daun, X. H.; Zhao, R. J.; Hu, Q. L.

    2016-05-01

    In the process of engineering application under the condition of hot water circulation pump, problems of stress concentration caused by the temperature rise may happen. In order to study the temperature field in bearing and electric motor chamber of the hot water circulation pump and optimize the structure, in present paper, the model of the shaft system is created through CREO. The model is analyzed by ANSYS workbench, in which the thermal boundary conditions are applied to calculate, which include the calorific values from the bearings, the thermal loss from electric motor and the temperature from the transporting medium. From the result, the finite element model can reflect the distribution of thermal field in hot water circulation pump. Further, the results show that the maximum temperature locates in the bearing chamber.The theoretical guidance for the electric motor heat dissipation design of the hot water circulation pump can be achieved.

  11. Testing Mantle Circulation Models

    NASA Astrophysics Data System (ADS)

    Webb, P.; Davies, D.; Davies, J.

    2008-12-01

    Over the past decade, a new family of mantle convection models have been developed, which are conditioned by recent plate motion history (e.g. Bunge et al., 1997). They are commonly known as 'mantle circulation models' and allow for comparisons between present-day model predictions and ever improving seismic tomography images (e.g. Li et al. 2008). In this work, we present results from systematic investigations into the influence of various model parameters upon final model prediction/tomography correlations, to obtain a better understanding of their relative importance. These include a range of material properties, such as the radial viscosity structure, the Clapeyron slope of mineral phase transitions and compressibility; in addition to other aspects, such as the initial condition for the simulation. For our comparisons, we focus in particular on two large robust mid-mantle seismic anomalies, which others have related to the subduction of the Farallon and Tethys plates (e.g. Romanowicz, 1980). While these features are recovered with some fidelity in most simulations, the match can vary greatly. We find that there is a great deal of information in this mismatch, which includes information on the plate motion history.

  12. Circulating Adiponectin and Risk of Endometrial Cancer

    PubMed Central

    Zheng, Qiaoli; Wu, Haijian; Cao, Jiang

    2015-01-01

    Background Adiponectin is an insulin-sensitizing hormone produced by adipocytes. It has been suggested to be involved in endometrial tumorigenesis. Published data have shown inconsistent results for the association between circulating adiponectin levels and endometrial cancer. In this study, we conducted a meta-analysis to evaluate the predictive value of circulating adiponectin levels on the development of endometrial cancer. Methods PubMed, Embase, ISI web of knowledge, and Cochrane databases were searched for all eligible studies, and the summary relative risk (SRR) was calculated. Additionally, we performed dose-response analysis with eight eligible studies. Results A total of 1,955 cases and 3,458 controls from 12 studies were included. The SRR for the ‘highest’ vs ‘lowest’ adiponectin levels indicated high adiponectin level reduced the risk of endometrial cancer [SRR = 0.40, 95% confidence interval (CI), 0.33–0.66]. Results from the subgroup analyses were consistent with the overall analysis. The SRR for each 1 µg/ml increase of adiponectin indicated a 3% reduction in endometrial cancer risk (95% CI: 2%–4%), and a 14% reduction for each increase of 5 µg/ml (95% CI: 9%–19%). No evidence of publication bias was found. Conclusions This meta-analysis demonstrates that low level of circulating adiponectin is a risk factor for endometrial cancer. PMID:26030130

  13. Multiple Circulating Cytokines Are Coelevated in Chronic Obstructive Pulmonary Disease

    PubMed Central

    Todd, Ian; John, Michelle; Bolton, Charlotte E.; Harrison, Timothy

    2016-01-01

    Inflammatory biomarkers, including cytokines, are associated with COPD, but the association of particular circulating cytokines with systemic pathology remains equivocal. To investigate this, we developed a protein microarray system to detect multiple cytokines in small volumes of serum. Fourteen cytokines were measured in serum from never-smokers, ex-smokers, current smokers, and COPD patients (GOLD stages 1–3). Certain individual circulating cytokines (particularly TNFα and IL-1β) were significantly elevated in concentration in the serum of particular COPD patients (and some current/ex-smokers without COPD) and may serve as markers of particularly significant systemic inflammation. However, numerous circulating cytokines were raised such that their combined, but not individual, elevation was significantly associated with severity of disease, and these may be further indicators of, and contributors to, the systemic inflammatory manifestations of COPD. The coelevation of numerous circulating cytokines in COPD is consistent with the insidious development, chronic nature, and systemic comorbidities of the disease. PMID:27524865

  14. Multiple Circulating Cytokines Are Coelevated in Chronic Obstructive Pulmonary Disease.

    PubMed

    Selvarajah, Senthooran; Todd, Ian; Tighe, Patrick J; John, Michelle; Bolton, Charlotte E; Harrison, Timothy; Fairclough, Lucy C

    2016-01-01

    Inflammatory biomarkers, including cytokines, are associated with COPD, but the association of particular circulating cytokines with systemic pathology remains equivocal. To investigate this, we developed a protein microarray system to detect multiple cytokines in small volumes of serum. Fourteen cytokines were measured in serum from never-smokers, ex-smokers, current smokers, and COPD patients (GOLD stages 1-3). Certain individual circulating cytokines (particularly TNFα and IL-1β) were significantly elevated in concentration in the serum of particular COPD patients (and some current/ex-smokers without COPD) and may serve as markers of particularly significant systemic inflammation. However, numerous circulating cytokines were raised such that their combined, but not individual, elevation was significantly associated with severity of disease, and these may be further indicators of, and contributors to, the systemic inflammatory manifestations of COPD. The coelevation of numerous circulating cytokines in COPD is consistent with the insidious development, chronic nature, and systemic comorbidities of the disease.

  15. When Prostate Cancer Circulates in the Bloodstream

    PubMed Central

    Vlaeminck-Guillem, Virginie

    2015-01-01

    Management of patients with prostate cancer is currently based on imperfect clinical, biological, radiological and pathological evaluation. Prostate cancer aggressiveness, including metastatic potential, remains difficult to accurately estimate. In an attempt to better adapt therapeutics to an individual (personalized medicine), reliable evaluation of the intrinsic molecular biology of the tumor is warranted, and particularly for all tumor sites (primary tumors and secondary sites) at any time of the disease progression. As a consequence of their natural tendency to grow (passive invasion) or as a consequence of an active blood vessel invasion by metastase-initiating cells, tumors shed various materials into the bloodstream. Major efforts have been recently made to develop powerful and accurate methods able to detect, quantify and/or analyze all these circulating tumor materials: circulating tumors cells, disseminating tumor cells, extracellular vesicles (including exosomes), nucleic acids, etc. The aim of this review is to summarize current knowledge about these circulating tumor materials and their applications in translational research. PMID:26854164

  16. Salinity Boundary Conditions and the Atlantic Meridional Overturning Circulation in Depth and Quasi-Isopycnic Coordinate Global Ocean Models

    DTIC Science & Technology

    2009-06-30

    2006. Investigating the causes of the response of the thermohaline circulation to past and future climate changes . J. Clim. 19, 1365-1387. Sun, S...Global climatic impacts of a collapse of the Atlantic thermohaline circulation , Clim. Change 54, 251– 267. Willebrand, J., et al., 2001. Circulation ...Rahmstorf, S., 1995. Bifurcations of the Atlantic thermohaline circulation in response to changes in the hydrological cycle. Nature 378, 145-149

  17. Circulating Progenitor Cells and Scleroderma

    PubMed Central

    2010-01-01

    Scleroderma (systemic sclerosis) is a disease of unknown origins that involves tissue ischemia and fibrosis in the skin and internal organs such as the lungs. The tissue ischemia is due to a lack of functional blood vessels and an inability to form new blood vessels. Bone marrow–derived circulating endothelial progenitor cells play a key role in blood vessel repair and neovascularization. Scleroderma patients appear to have defects in the number and function of circulating endothelial progenitor cells. Scleroderma patients also develop fibrotic lesions, possibly as the result of tissue ischemia. Fibroblast-like cells called fibrocytes that differentiate from a different pool of bone marrow–derived circulating progenitor cells seem to be involved in this process. Manipulating the production, function, and differentiation of circulating progenitor cells represents an exciting new possibility for treating scleroderma. PMID:18638425

  18. LLNL Ocean General Circulation Model

    SciTech Connect

    Wickett, M. E.; Caldeira, K.; Duffy, P.

    2005-12-29

    The LLNL OGCM is a numerical ocean modeling tool for use in studying ocean circulation over a wide range of space and time scales, with primary applications to climate change and carbon cycle science.

  19. Modelling Circulation Control by Blowing

    DTIC Science & Technology

    1984-08-01

    circulation control is initially presented for the Coanda flaw of a wail jot around a circular cylinder in a free stream. The decay in the jet momentum...Jue to viscojs and ontiainment effects , has boon represented in the model by decaying the strength of each vortex is it flows downstream frorn the...slot. The model’s application has then boon extended to predict the effect of circulation control on other sh&,,os of aerofoll. The paper includes the

  20. DOE lost circulation technology development

    SciTech Connect

    Glowka, D.A.; Staller, G.E.; Sattler, A.R.

    1996-09-01

    Lost circulation is a problem common in both the geothermal and the solution mining industries. In both cases, drilling is on a relatively large scale (geothermal holes can be as large as 26 inches). Lost circulation technology development for geothermal drilling has been in progress at Sandia National Laboratories for more than 15 years. The initial work centered on lost circulation materials, but testing and modeling indicated that if the aperture of a loss zone is very large (larger than the drill bit nozzles) it cannot be plugged by simply adding materials to the drilling fluid. Thus, the lost circulation work evolved to include: (1) Development of metering techniques that accurately measure and characterize drilling fluid inflow and outflow for rapid diagnosis of los circulation and/or fluid balance while drilling. (2) Construction of a laboratory facility for testing drillable straddle packers (to improve the plugging efficiency of cementing operations) and the actual testing of components of the straddle packer. (3) Construction of a laboratory facility for the testing of candidate porous fabrics as a part of a program to develop a porous packer that places polyurethane foam into a loss zone. (4) Implementing (with Halliburton and CalEnergy Company), a program to test cementitious lost circulation material as an alternative to Portland cement.

  1. Ockham's Razorblade Shaving Wind-Induced Circulation

    NASA Astrophysics Data System (ADS)

    Bergmann, Juan Carlos

    2010-05-01

    Terrestrial physical oceanography is fortunate because of the existence of the continents that divide the low-latitude oceans into basins. At first glance, the previous statement appears to be not obvious because an ocean-planet should be much simpler to describe. Simple-case explanation is the central aspect of Ockham's Razorblade: If a theory fails to describe the most-simple case properly, the theory is, at least, ‘not good'. Also Descartes' methodical rules take the most-simple case as starting point. The analysis of wind-induced circulation on an ocean-planet will support the initial statement. Earth's south hemisphere is dominated by the oceans. The continents' influence on the zonal-average zonal-wind climate is relatively small. Therefore, South Hemisphere's zonal wind pattern is a relatively good proxy for that of an ocean planet. Application of this wind-stress pattern to an ocean planet yields reasonable meridional mass-flow results from the polar-regions down to the high-pressure belts: Down-welling and up-welling of water-mass are approximately balanced. However, the entire tropical circulation can in principle not be closed because there is only down-welling - even if the extreme down-welling in the equatorial belt (± 8°, with a singularity at the equator) is disregarded. The only input to the calculations is the observed terrestrial south-hemisphere zonal wind-stress pattern. Meridional stress is irrelevant because it produces a closed zonal Ekman-transport around the ocean planet (sic!). Vertical mass-transport is calculated from the divergence of the wind-induced meridional Ekman-mass-transport, which in its turn is a necessary consequence of angular-momentum conservation. No assumptions are made on how the return-flows at depth are forced because the wind-force equations cannot contribute hereto. This circumstance expresses a fundamental difference to atmospheric circulation, where mechanical forcing is caused by the pressure-fields that

  2. Connection between mesopause temperature, circulation and noctilucent clouds

    NASA Technical Reports Server (NTRS)

    Gartner, V.; Memmesheimer, M.

    1985-01-01

    To investigate the connection between mesopause temperature in summer and the induced circulation upon possible formation of the observed polar mesospheric (noctilucent) cloud layer (PMC), a two-dimensional semiempirical model is used to calculate the zonally averaged diabatic circulation. On the basis of the calculations, one may draw the following conclusions: (1) if the large departures from radiative equilibrium which occur at the summer mesopause at high latitudes should be balanced by adiabatic processes of the mean circulation alone, a vigorous circulation is needed (there is some evidence that such a vigorous circulation has been observed); (2) the vertical velocities of some cm/s at the polar summertime mesopause will support the formation of polar mesospheric clouds, because those large wind speeds support larger ice particles against gravitational sedimentation; and (3) a region of mild subsidence in the summertime midlatitude mesosphere due to the effect of nonlinear temperature advection would tend to limit the occurrence of ice particles to latitudes poleward of about 55 deg.

  3. Circulation Across 52w In The North Atlantic

    NASA Astrophysics Data System (ADS)

    Hall, M.; Joyce, T.; Pickart, R.; Smethie, W.

    The zonal circulation across the 52W meridian in the North Atlantic is described, as deduced from hydrographic and ADCP data. The data were collected in a 1997 cruise as part of the World Ocean Circulation Experiment, from the Grand Banks southeast of Newfoundland down to Suriname, South America (near 7 deg N, 53.5 deg W), and included shipboard and lowered ADCP (SADCP and LADCP) data along with hydro- graphic, nutrient, and CFC data. To analyze the circulation, first, geostrophic velocity shear was calculated using the hydrographic data. Next, an initial reference level ve- locity for each station pair was obtained by comparison of the geostrophic shear with the SADCP and LADCP data. Finally, an inverse calculation was applied, which con- served mass and silica within prescribed tolerance levels in 17 neutral density layers as well as overall. Because LADCP data were lacking over a crucial subset of stations in the northern Deep Western Boundary Current and throughout the Gulf Stream sys- tem, error bars on the final circulation are necessarily large. This result emphasizes the importance of collecting LADCP data concurrently with hydrographic data. Results will be presented in terms of velocity sections, transport streamfunctions, and total transports for major currents. Most surprising in the results is the strength of the deep circulation away from the boundary currents.

  4. The relationship of maternal characteristics and circulating progesterone concentrations with reproductive outcome in the bottlenose dolphin (Tursiops truncatus) after artificial insemination, with and without ovulation induction, and natural breeding.

    PubMed

    O'Brien, J K; Robeck, T R

    2012-08-01

    Bottlenose dolphins (Tursiops truncatus) undergoing natural breeding and artificial insemination (AI) were examined to characterize serum progesterone concentrations and determine relationships among age, parity, and reproductive outcome. Progesterone profiles of five cycle types (n = 119 total cycles from 54 animals) were characterized as follows: (i) conception and production of a live term calf (conceptive-term, n = 73); (ii) conception and abortion after Day 60 (conceptive-abortion, n = 12); (iii) unknown conception status with prolonged, elevated progesterone and absence of a fetus (conceptive-unknown, n = 14); (iv) conception failure with normal luteal phase progesterone concentrations (non-conceptive, n = 14, AI cycles only); and (v) conception failure with progesterone insufficiency occuring after spontaneous ovulation or owing to premature ovulation induction using GnRH (non-conceptive-PI, n = 6, AI cycles only). By Day 21 post-insemination (PI), progesterone concentrations were similar (P > 0.05) among conceptive-term, conceptive-abortion and conceptive-unknown, and higher (P < 0.05) for conceptive-term than non-conceptive and non-conceptive-PI cycles. Progesterone concentrations of known conceptive cycles peaked by Week 7 PI (P < 0.05) and remained elevated for the remainder of pregnancy (Weeks 8 up to 54, ≥ 5 days pre-partum). During midpregnancy (Days 121-240), conceptive-term cycles had higher (P > 0.05) progesterone concentrations than conceptive-abortion and unknown conception status cycles. Parity was not associated with reproductive outcome based on cycle type (P > 0.05). Age of females in conceptive-unknown (26.5 ± 10.1 yrs) and conceptive-abortion (22.1 ± 9.4 yrs) groups was higher (P < 0.05) than in conceptive-term (15.7 ± 7.2 yrs). The conceptive-unknown cycle type possibly represents undetected early embryonic loss occurring before Day 60 PI. Length of gestation using known conception dates was 376.1 ± 11.0 days and the range of this

  5. Laboratory measurements of the generation and evolution of Langmuir circulations

    NASA Astrophysics Data System (ADS)

    Melville, W. Kendall; Shear, Robert; Veron, Fabrice

    1998-06-01

    We present laboratory measurements of the generation and evolution of Langmuir circulations as an instability of a wind-driven surface shear layer. The shear layer, which is generated by an accelerating wind starting from rest above a quiescent water surface, both accelerates and deepens monotonically until the inception of the Langmuir circulations. The Langmuir circulations closely follow the initial growth of the wind waves and rapidly lead to vertical mixing of the horizontal momentum and a deceleration of the surface layer. Prior to the appearance of the Langmuir circulations, the depth of the shear layer scales with (vt)1/2 (v is the kinematic viscosity and t is time), in accordance with molecular rather than turbulent transport. For final wind speeds in the range 3 to 5 m s[minus sign]1, the wavenumber of the most unstable Langmuir circulation normalized by the surface wavenumber, k*lc, is 0.68±0.24, at a reciprocal Langmuir number, La[minus sign]1, of 52±21. The observations are compared with available theoretical results, although none are directly applicable to the conditions of the experiments. The implications of this work for the generation and evolution of Langmuir circulations in the ocean and other natural water bodies are discussed.

  6. Application of remote sensing to study nearshore circulation. [and the continental shelf

    NASA Technical Reports Server (NTRS)

    Zeigler, J.; Lobecker, R.; Stauble, D.; Welch, C.; Haas, L.; Fang, C. S.

    1974-01-01

    The research to use remote sensing techniques for studying the continental shelf is reported. The studies reported include: (1) nearshore circulation in the vincinity of a natural tidal inlet; (2) identification of indicators of biological activity; (3) remote navigation system for tracking free drifting buoys; (4) experimental design of an estuaring tidal circulation; and (5) Skylab support work.

  7. Alcohol Calorie Calculator

    MedlinePlus

    ... Alcohol Calorie Calculator Weekly Total 0 Calories Alcohol Calorie Calculator Find out the number of beer and ... Calories College Alcohol Policies Interactive Body Calculators Alcohol Calorie Calculator Alcohol Cost Calculator Alcohol BAC Calculator Alcohol ...

  8. [Circulating nucleic acids and infertility].

    PubMed

    Scalici, E; Mullet, T; Ferrières Hoa, A; Gala, A; Loup, V; Anahory, T; Belloc, S; Hamamah, S

    2015-09-01

    Circulating nucleic acids (cell-free DNA and microRNAs) have for particularity to be easily detectable in the biological fluids of the body. Therefore, they constitute biomarkers of interest in female and male infertility care. Indeed, in female, they can be used to detect ovarian reserve disorders (polycystic ovary syndrome and low functional ovarian reserve) as well as to assess follicular microenvironment quality. Moreover, in men, their expression levels can vary in case of spermatogenesis abnormalities. Finally, circulating nucleic acids have also the ability to predict successfully the quality of in vitro embryo development. Their multiple contributions during assisted reproductive technology (ART) make of them biomarkers of interest, for the development of new diagnostic and/or prognostic tests, applied to our specialty. Circulating nucleic acids would so offer the possibility of personalized medical care for infertile couples in ART.

  9. Bandwidth broadening for stripline circulator

    NASA Astrophysics Data System (ADS)

    Chao, Hsien-Wen; Wu, Shi-Yao; Chang, Tsun-Hsu

    2017-02-01

    This work provides a detailed analysis and simulation to demonstrate how to broaden the operating bandwidth of a circulator. A double-Y junction circulator is designed, and the shape of the central stripline is optimized with the knowledge of a modified equation. The equation predicts two resonant conditions. The overlapping of the two resonant conditions jointly constitutes the broad bandwidth. The bias magnetic field is simulated and then used in full electromagnetic-wave simulation. The designed circulator was fabricated in the S-band for communication purpose. The measured results agree very well with simulation. The overall operation range is from 1643 to 2027 MHz with the insertion loss less than 0.35 dB, reflection, and isolation better than 20 dB. The mechanism will be discussed.

  10. Noise Reduction Through Circulation Control

    NASA Technical Reports Server (NTRS)

    Munro, Scott E.; Ahuja, K. K.; Englar, Robert J.

    2005-01-01

    Circulation control technology uses tangential blowing around a rounded trailing edge or a leading edge to change the force and moment characteristics of an aerodynamic body. This technology has been applied to circular cylinders, wings, helicopter rotors, and even to automobiles for improved aerodynamic performance. Only limited research has been conducted on the acoustic of this technology. Since wing flaps contribute to the environmental noise of an aircraft, an alternate blown high lift system without complex mechanical flaps could prove beneficial in reducing the noise of an approaching aircraft. Thus, in this study, a direct comparison of the acoustic characteristics of high lift systems employing a circulation control wing configuration and a conventional wing flapped configuration has been made. These results indicate that acoustically, a circulation control wing high lift system could be considerably more acceptable than a wing with conventional mechanical flaps.

  11. Circulating a Good Service Model at Its Core: Circulation!

    ERIC Educational Resources Information Center

    Hernandez, Edmee Sofia; Germain, Carol Anne, Ed.

    2009-01-01

    Circulation is the library's tireless foot soldier: it serves as the front gate to the library's services and resources. This service point is where most patrons enter and leave; and experience their first and last impressions--impressions that linger. In an age when academic libraries are facing meager budgets and declining usage statistics, this…

  12. Detection of Circulating Tumor Cells

    PubMed Central

    Terstappen, Leon W. M. M.

    2014-01-01

    The increasing number of treatment options for patients with metastatic carcinomas has created an accompanying need for methods to determine if the tumor will be responsive to the intended therapy and to monitor its effectiveness. Ideally, these methods would be noninvasive and provide quantitative real-time analysis of tumor activity in a variety of carcinomas. Assessment of circulating tumor cells shed into the blood during metastasis may satisfy this need. Here we review the CellSearch technology used for the detection of circulating tumor cells and discuss potential future directions for improvements. PMID:25133014

  13. Photon and neutrino-pair emission from circulating quantum ions

    NASA Astrophysics Data System (ADS)

    Yoshimura, M.; Sasao, N.

    2016-06-01

    The recent proposal of a photon and a neutrino-pair beam is investigated in detail. Production rates, both differential and total, of a single photon, two photons, and a neutrino pair emitted from quantum ions in circular motion are given for any velocity of ion. This part is an extension of our previous calculations at highest energies to lower energies of circulating ions, and hopefully helps to identify the new process of quantum ion circulation at a low energy ring. We clarify how to utilize the circulating ion for a new source of coherent neutrino beam despite much stronger background photons. Once one verifies that the coherence is maintained in the initial phases of time evolution after laser irradiation, large background photon emission rates are not an obstacle against utilizing the extracted neutrino-pair beam.

  14. Transient analysis of the 1991 Hijiori Shallow Reservoir Circulation Test

    SciTech Connect

    Hyodo, M.; Shinohara, N.; Takasugi, S.; Wright, C.A.; Conant, R..

    1996-01-24

    Like any dynamic system, HDR reservoirs cannot be fully characterized by their steady-state behavior. Circulation tests analysis should be performed on both the steady-state response and the transient response of HDR systems. Transient analysis allows not only estimation of critical reservoir parameters and how these parameters change with operating conditions / history, but transient analysis also aids in evaluating the feasibility of various modes of HDR system operation (base load, load following, etc.). This paper details the transient analysis of NEDO's FY 1991 Shallow Reservoir Circulation Test at the Hijiori HDR site in Japan. Reservoir fluid storage is carefully bounded through the employment of two distinct methods for calculation of the fluid storage from the observed transient response. A brief discussion is also included of the distribution of reservoir fluid storage; the relationship between pressure, reservoir stress, and apparent reservoir capacitance; and appropriate circulation test design to facilitate transient analysis.

  15. Seawater bicarbonate removal during hydrothermal circulation

    NASA Astrophysics Data System (ADS)

    Proskurowski, G. K.; Seewald, J.; Sylva, S. P.; Reeves, E.; Lilley, M. D.

    2013-12-01

    High temperature fluids sampled at hydrothermal vents represent a complex alteration product of water-rock reactions on a multi-component mixture of source fluids. Sources to high-temperature hydrothermal samples include the 'original' seawater present in the recharge limb of circulation, magmatically influenced fluids added at depth as well as any seawater entrained during sampling. High-temperature hydrothermal fluids are typically enriched in magmatic volatiles, with CO2 the dominant species, characterized by concentrations of 10's-100's of mmol/kg (1, 2). Typically, the high concentration of CO2 relative to background seawater bicarbonate concentrations (~2.3 mmol/kg) obscures a full analysis of the fate of seawater bicarbonate during high-temperature hydrothermal circulation. Here we present data from a suite of samples collected over the past 15 years from high-temperature hydrothermal vents at 9N, Endeavour, Lau Basin, and the MAR that have endmember CO2 concentrations less than 10 mmol/kg. Using stable and radiocarbon isotope measurements these samples provide a unique opportunity to examine the balance between 'original' seawater bicarbonate and CO2 added from magmatic sources. Multiple lines of evidence from multiple hydrothermal settings consistently points to the removal of ~80% of the 'original' 2.3 mmol/kg seawater bicarbonate. Assuming that this removal occurs in the low-temperature, 'recharge' limb of hydrothermal circulation, this removal process is widely occurring and has important contributions to the global carbon cycle over geologic time. 1. Lilley MD, Butterfield DA, Lupton JE, & Olson EJ (2003) Magmatic events can produce rapid changes in hydrothermal vent chemistry. Nature 422(6934):878-881. 2. Seewald J, Cruse A, & Saccocia P (2003) Aqueous volatiles in hydrothermal fluids from the Main Endeavour Field, northern Juan de Fuca Ridge: temporal variability following earthquake activity. Earth and Planetary Science Letters 216(4):575-590.

  16. Numerical modelling of geothermal and reflux circulation in Enewetak Atoll: Implications for dolomitization

    USGS Publications Warehouse

    Jones, G.; Whitaker, F.; Smart, P.; Sanford, W.

    2000-01-01

    Two types of regional-scale seawater circulation have been proposed to explain the formation of Enewetak Atoll dolomites: geothermal and reflux circulation. We have used a finite element groundwater flow model to examine the pattern, magnitude and dynamic interaction of these two different circulation mechanisms in Enewetak Atoll. Geothermal circulation is concentrated around the atoll-margin whereas refluxing mesosaline brines flow from the atoll interior towards the margin to restrict and eventually shut off geothermal circulation. Refluxing brines of 36-80??? can account for the salinity signature recorded in dolomite fluid inclusions. Distributions of fluid flux and Mg mass-balance calculations suggest that both geothermal and reflux circulation mechanisms could account for the observed distribution of dolomite in Enewetak Atoll. Furthermore, the atoll interior may be extensively dolomitized as observed in other atolls. (C) 2000 Elsevier Science B.V. All rights reserved.Two types of regional-scale seawater circulation have been proposed to explain the formation of Enewetak Atoll dolomites: geothermal and reflux circulation. We have used a finite element groundwater flow model to examine the pattern, magnitude and dynamic interaction of these two different circulation mechanisms in Enewetak Atoll. Geothermal circulation is concentrated around the atoll-margin whereas refluxing mesosaline brines flow from the atoll interior towards the margin to restrict and eventually shut off geothermal circulation. Refluxing brines of 36-80 per mil can account for the salinity signature recorded in dolomite fluid inclusions. Distributions of fluid flux and Mg mass-balance calculations suggest that both geothermal and reflux circulation mechanisms could account for the observed distribution of dolomite in Enewetak Atoll. Furthermore, the atoll interior may be extensively dolomitized as observed in other atolls.

  17. ENDEMIC ORTHOPOXVIRUS CIRCULATING IN PROCYONIDS IN MEXICO.

    PubMed

    Gallardo-Romero, Nadia F; Aréchiga-Ceballos, Nidia; Emerson, Ginny L; Martínez-Martínez, Flor O; Doty, Jeffrey B; Nakazawa, Yoshinori J; Rendón-Franco, Emilio; Muñoz-García, Claudia I; Villanueva-García, Claudia; Ramírez-Cid, Citlali; Gama-Campillo, Lilia M; Gual-Sill, Fernando; Aguilar-Setién, Álvaro; Carroll, Darin S

    2016-07-01

    Limited serosurveillance studies suggested that orthopoxviruses (OPXV) are widespread in the US (e.g., Raccoonpox virus, Skunkpox virus, Volepox virus) and Brazil (Vaccinia virus); however, their animal reservoir(s) remain unconfirmed. Mexican mammal diversity includes several species related to those in which evidence for OPXV infections has been found (Oryzomys, Peromyscus, Microtus, and Procyonidae). The presence of these groups of mammals in Mexico and the evidence of their possible involvement in the maintenance of OPXV in nature suggest the same or similar OPXV are circulating in Mexico. We tested 201 sera from 129 procyonids via modified enzyme-linked immunosorbent assay (ELISA) and Western blot (WB) to estimate OPXV antibody prevalence in these animals. We detected a prevalence of 16.67% in Nasua narica (white-nosed coati), 35% in Procyon lotor (raccoon), and 30.4% in Bassariscus astutus (ring-tailed cat) when tested by either ELISA or WB. Western blot results presented protein bands consistent with the size of some OPXV immunodominant bands (14, 18, 32, 36, and 62 kDa). These results support the hypothesis that OPXV circulate in at least three genera of Procyonidae in Central and Southeast Mexico.

  18. Predictive models of circulating fluidized bed combustors

    SciTech Connect

    Gidaspow, D.

    1992-07-01

    Steady flows influenced by walls cannot be described by inviscid models. Flows in circulating fluidized beds have significant wall effects. Particles in the form of clusters or layers can be seen to run down the walls. Hence modeling of circulating fluidized beds (CFB) without a viscosity is not possible. However, in interpreting Equations (8-1) and (8-2) it must be kept in mind that CFB or most other two phase flows are never in a true steady state. Then the viscosity in Equations (8-1) and (8-2) may not be the true fluid viscosity to be discussed next, but an Eddy type viscosity caused by two phase flow oscillations usually referred to as turbulence. In view of the transient nature of two-phase flow, the drag and the boundary layer thickness may not be proportional to the square root of the intrinsic viscosity but depend upon it to a much smaller extent. As another example, liquid-solid flow and settling of colloidal particles in a lamella electrosettler the settling process is only moderately affected by viscosity. Inviscid flow with settling is a good first approximation to this electric field driven process. The physical meaning of the particulate phase viscosity is described in detail in the chapter on kinetic theory. Here the conventional derivation resented in single phase fluid mechanics is generalized to multiphase flow.

  19. Neural Control of the Circulation

    ERIC Educational Resources Information Center

    Thomas, Gail D.

    2011-01-01

    The purpose of this brief review is to highlight key concepts about the neural control of the circulation that graduate and medical students should be expected to incorporate into their general knowledge of human physiology. The focus is largely on the sympathetic nerves, which have a dominant role in cardiovascular control due to their effects to…

  20. In vivo acoustic and photoacoustic focusing of circulating cells

    NASA Astrophysics Data System (ADS)

    Galanzha, Ekaterina I.; Viegas, Mark G.; Malinsky, Taras I.; Melerzanov, Alexander V.; Juratli, Mazen A.; Sarimollaoglu, Mustafa; Nedosekin, Dmitry A.; Zharov, Vladimir P.

    2016-03-01

    In vivo flow cytometry using vessels as natural tubes with native cell flows has revolutionized the study of rare circulating tumor cells in a complex blood background. However, the presence of many blood cells in the detection volume makes it difficult to count each cell in this volume. We introduce method for manipulation of circulating cells in vivo with the use of gradient acoustic forces induced by ultrasound and photoacoustic waves. In a murine model, we demonstrated cell trapping, redirecting and focusing in blood and lymph flow into a tight stream, noninvasive wall-free transportation of blood, and the potential for photoacoustic detection of sickle cells without labeling and of leukocytes targeted by functionalized nanoparticles. Integration of cell focusing with intravital imaging methods may provide a versatile biological tool for single-cell analysis in circulation, with a focus on in vivo needleless blood tests, and preclinical studies of human diseases in animal models.

  1. In vivo acoustic and photoacoustic focusing of circulating cells

    PubMed Central

    Galanzha, Ekaterina I.; Viegas, Mark G.; Malinsky, Taras I.; Melerzanov, Alexander V.; Juratli, Mazen A.; Sarimollaoglu, Mustafa; Nedosekin, Dmitry A.; Zharov, Vladimir P.

    2016-01-01

    In vivo flow cytometry using vessels as natural tubes with native cell flows has revolutionized the study of rare circulating tumor cells in a complex blood background. However, the presence of many blood cells in the detection volume makes it difficult to count each cell in this volume. We introduce method for manipulation of circulating cells in vivo with the use of gradient acoustic forces induced by ultrasound and photoacoustic waves. In a murine model, we demonstrated cell trapping, redirecting and focusing in blood and lymph flow into a tight stream, noninvasive wall-free transportation of blood, and the potential for photoacoustic detection of sickle cells without labeling and of leukocytes targeted by functionalized nanoparticles. Integration of cell focusing with intravital imaging methods may provide a versatile biological tool for single-cell analysis in circulation, with a focus on in vivo needleless blood tests, and preclinical studies of human diseases in animal models. PMID:26979811

  2. Isotopic composition of precipitation during different atmospheric circulation patterns

    NASA Astrophysics Data System (ADS)

    Brenčič, Mihael; Kononova, Nina; Vreča, Polona

    2016-04-01

    Precipitation generating processes depend on atmospheric circulation patterns and consequently it is expected that its water stable isotopic composition of hydrogen and oxygen is related to them. Precipitation generated at similar atmospheric circulation patterns should have similar empirical distribution of δ2H and δ18O values. There are several approaches in which atmospheric circulation patterns are classified as elementary air circulation mechanisms - ECM; in our approach we have applied Dzerdzeevskii classification. Two types of models of relation between ECM and isotopic composition of precipitation are proposed; first is based on the linear combination of δ2H and δ18O values with precipitation amount weighted average (Brenčič et al., 2015) and the second new one is based on the multiple regression approach. Both approaches make possible also to estimate empirical distributions' dispersion parameters. Application of the models is illustrated on the precipitation records from Ljubljana and Portorož GNIP stations, Slovenia. Estimated values of the parameters for empirical distributions of δ2H and δ18O of each ECM subtype have shown that calculated estimates are reasonable. Brenčič, M., Kononova, N.K., Vreča, P., 2015: Relation between isotopic composition of precipitation and atmospheric circulation patterns. Journal of Hydrology 529, 1422-1432: doi: 10.1016/j.jhydrol.2015.08.040

  3. Emission Corridors Preserving the Atlantic Ocean Thermohaline Circulation

    NASA Astrophysics Data System (ADS)

    Zickfeld, K.; Bruckner, T.

    2001-12-01

    The Atlantic thermohaline circulation (THC) transports large amounts of heat northward, acting as a heating system for the northern North Atlantic and north-western Europe. A large number of model simulations have shown the THC to be self-sustaining within certain limits, with well-defined thresholds where the circulation shuts down. Manabe and Stouffer (1993), for example, have simulated a complete shutdown of the THC for a quadrupling of atmospheric CO2. Because of the possibly severe consequences that a collapse of the THC would have upon the North Atlantic and north-western Europe, such an event may be considered as "dangerous anthropogenic interference with the climate system" that Article 2 of the UN Framework Convention on Climate Change (UNFCCC) calls to avoid. Here we present bundles of emission paths (the so called "emission corridors") that preserve the Atlantic thermohaline circulation. These corridors are calculated on the methodological and conceptual basis of the Tolerable Windows Approach. For this purpose a multi-gas reduced-form climate model has been supplemented by a dynamic Stommel-type boxmodel of the Atlantic thermohaline circulation. Both models allow for the relevant uncertainties (i.e., emissions of non-CO2 greenhouse gases, climate sensitivity, Atlantic hydrological sensitivity) to be taken into account. The sensitivity of emissions corridors with respect to the uncertain parameters is explored and the implications for a climate policy committed to the preservation of the Atlantic thermohaline circulation in the sense of Article 2 are discussed.

  4. Relation between isotopic composition of precipitation and atmospheric circulation patterns

    NASA Astrophysics Data System (ADS)

    Brenčič, Mihael; Kononova, Nina K.; Vreča, Polona

    2015-10-01

    Precipitation generating processes depend on atmospheric circulation patterns and consequently it is expected that its water stable isotopic composition of hydrogen and oxygen is related to them. Precipitation generated at similar atmospheric circulation patterns should have similar empirical distribution of δ2H and δ18O values. Mathematical model based on the linear combination of δ2H and δ18O values and on precipitation amount weighted average related to elementary air circulation mechanisms - ECM is proposed. The model enables estimation of average δ2H and δ18O values and their standard deviation for the precipitation generated at distinctive atmospheric circulation patterns. Approach in which atmospheric circulation patterns were classified as ECM based on the Dzerdzeevskii classification was applied. Application of the model is illustrated on the long term precipitation record from Ljubljana GNIP station Slovenia. Estimated values of the parameters for empirical distributions of δ2H and δ18O of each ECM subtype have shown that calculated estimates are reasonable. Further applications of the proposed model enable new insight into the understanding of isotopes spatial and temporal distribution in precipitation important also for better understanding of climate proxies.

  5. Control of glomerular filtration rate by circulating angiotensin II.

    PubMed

    Hall, J E; Coleman, T G; Guyton, A C; Kastner, P R; Granger, J P

    1981-09-01

    Previous studies from our laboratory have provided evidence that the renin-angiotensin system plays an important role in controlling glomerular filtration rate (GFR) through an efferent arteriolar vasoconstrictor mechanism; however, the relative importance of circulating versus intrarenally formed angiotensin II (ANG II) in this control has not been determined. In the present study, the role of circulating ANG II in regulating GFR during reduced renal artery pressure (RAP) was examined in sodium-depleted dogs. After 90 min of infusion of the angiotensin-converting enzyme inhibitor SQ 14225, which presumably inhibited formation of both circulating and intrarenal ANG II, reduction of RAP to 81 +/- 2 mmHg resulted in marked decreases in GFR, filtration fraction (FF), and calculated efferent arteriolar resistance (RE), whereas renal blood flow (RBF) was maintained approximately 40% above initial control levels determined before SQ 14225 infusion. Replacement of circulating ANG II during SQ 14225 infusion, by intravenous infusion of ANG II at rates that decreased RBF to control levels, increased GFR, FF, and RE to levels not significantly different from control while RAP was maintained constant by aortic constriction. These observations suggest that circulating ANG II plays an important role in regulating RE and GFR during reductions in RAP. The importance of intrarenally formed ANG II in controlling GFR remains to be determined.

  6. Tracers of Past Ocean Circulation

    NASA Astrophysics Data System (ADS)

    Lynch-Stieglitz, J.

    2003-12-01

    Information about how the ocean circulated during the past is useful in understanding changes in ocean and atmospheric chemistry, changes in the fluxes of heat and freshwater between the ocean and atmosphere, and changes in global wind patterns. The circulation of surface waters in the ocean leaves an imprint on sea surface temperature, and is also inextricably linked to the patterns of oceanic productivity. Much valuable information about past ocean circulation has been inferred from reconstructions of surface ocean temperature and productivity, which are covered in separate chapters. Here the focus is on the geochemical tracers that are used to infer the flow patterns and mixing of subsurface water masses.Several decades ago it was realized that chemistry of the shells of benthic foraminifera (carbon isotope and Cd/Ca ratios) carried an imprint of the nutrient content of deep-water masses (Shackleton, 1977; Broecker, 1982; Boyle, 1981). This led rapidly to the recognition that the water masses in the Atlantic Ocean were arrayed differently during the last glacial maximum than they are today, and the hypothesis that the glacial arrangement reflected a diminished contribution of low-nutrient North Atlantic deep water (NADW) ( Curry and Lohmann, 1982; Boyle and Keigwin, 1982). More detailed spatial reconstructions indicated a shallow nutrient-depleted water mass overlying a more nutrient-rich water mass in the glacial Atlantic. These findings spurred advances not only in geochemistry but in oceanography and climatology, as workers in these fields attempted to simulate the inferred glacial circulation patterns and assess the vulnerability of the modern ocean circulation to changes such as observed for the last ice age.While the nutrient distributions in the glacial Atlantic Ocean were consistent with a diminished flow of NADW, they also could have reflected an increase in inflow from the South Atlantic and/or a shallower yet undiminished deep-water mass. Clearly

  7. A hybrid fuzzy logic and extreme learning machine for improving efficiency of circulating water systems in power generation plant

    NASA Astrophysics Data System (ADS)

    Aziz, Nur Liyana Afiqah Abdul; Siah Yap, Keem; Afif Bunyamin, Muhammad

    2013-06-01

    This paper presents a new approach of the fault detection for improving efficiency of circulating water system (CWS) in a power generation plant using a hybrid Fuzzy Logic System (FLS) and Extreme Learning Machine (ELM) neural network. The FLS is a mathematical tool for calculating the uncertainties where precision and significance are applied in the real world. It is based on natural language which has the ability of "computing the word". The ELM is an extremely fast learning algorithm for neural network that can completed the training cycle in a very short time. By combining the FLS and ELM, new hybrid model, i.e., FLS-ELM is developed. The applicability of this proposed hybrid model is validated in fault detection in CWS which may help to improve overall efficiency of power generation plant, hence, consuming less natural recourses and producing less pollutions.

  8. Thermohaline circulation and its box models simulation

    NASA Astrophysics Data System (ADS)

    Bazyura, Kateryna; Polonsky, Alexander; Sannikov, Viktor

    2014-05-01

    cases of using linear and nonlinear seawater state equation. In the frame of four-box model it is shown that: 1) The occurrence of the thermohaline catastrophe, which is likely happened at Younger Dryas period or developed as Heinrich events in the past, is improbable in modern climate epoch. 2) Choice of nonlinear seawater equitation of state leads to stabilization of warm mode of THC, which corresponds to modern climate state. 3) Typical white noise in heat and freshwater fluxes leads to generation of multidecadal oscillations of volume transport. Time-scale of these oscillations coincides with Atlantic Multidecadal oscillation periodicity. So, it is shown that that recent climate is characterized by quasi-periodical stable multidecadal THC warm regime. Stocker, T. F., 2000: Past and future reorganisations in the climate system. Quat. Sci.Rev, Vol. 19, P.301-319. Clark U., 2002: The role of the thermohaline circulation in abrupt climate change. Nature. Vol. 415, P.863-869. Rahmstorf S., 2002: Ocean circulation and climate during the past 120000 years. Nature. Vol. 419, P.207-214. Alley, R. B. & Clark, P. U., 1999: The deglaciation of the Northern Hemisphere: a global perspective. Annu.Rev. Earth Planet. Sci. Vol. 27, P.149-182. Griffies S.M., Tziperman E., 1995: A linear thermohaline oscillator driven by stochastic atmospheric forcing. Journal of Climate. Vol. 8. P. 2440-2453.

  9. Physiology of the fetal circulation.

    PubMed

    Kiserud, Torvid

    2005-12-01

    Our understanding of fetal circulatory physiology is based on experimental animal data, and this continues to be an important source of new insight into developmental mechanisms. A growing number of human studies have investigated the human physiology, with results that are similar but not identical to those from animal studies. It is time to appreciate these differences and base more of our clinical approach on human physiology. Accordingly, the present review focuses on distributional patterns and adaptational mechanisms that were mainly discovered by human studies. These include cardiac output, pulmonary and placental circulation, fetal brain and liver, venous return to the heart, and the fetal shunts (ductus venosus, foramen ovale and ductus arteriosus). Placental compromise induces a set of adaptational and compensational mechanisms reflecting the plasticity of the developing circulation, with both short- and long-term implications. Some of these aspects have become part of the clinical physiology of today with consequences for surveillance and treatment.

  10. Middle atmosphere general circulation statistics

    NASA Technical Reports Server (NTRS)

    Geller, M. A.

    1985-01-01

    With the increased availability of remote sensing data for the middle atmosphere from satellites, more analyses of the middle atmosphere circulation are being published. Some of these are process studies for limited periods, and some are statistical analyses of middle atmosphere general circulation statistics. Results from the latter class of studies will be reviewed. These include analysis of the zonally averaged middle atmosphere structure, temperature, and zonal winds; analysis of planetary wave structures, analysis of heat and momentum fluxes; and analysis of Eliassen-and-Palm flux vectors and flux divergences. Emphasis is on the annual march of these quantities; Northern and Southern Hemisphere asymmetries; and interannual variability in these statistics. Statistics involving the global ozone distribution and transports of ozone are also discussed.

  11. Spaceborne studies of ocean circulation

    NASA Technical Reports Server (NTRS)

    Patzert, W. C.

    1984-01-01

    The history and near-term future of ocean remote sensing to study ocean circulation are examined. Seasat provided the first-ever global data sets of sea surface topography (altimeter) and marine winds (scatterometer) and laid the foundation for the next generation of satellite missions planned for the late 1980s. The future missions are the next generation of altimeter and scatterometer to be flown aboard TOPEX (TOPography EXperiment) and NROSS (Navy Remote Sensing System), respectively. The data from these satellites will be coordinated with measurements made at sea to determine the driving forces of ocean circulation and to study the oceans' role in climate variability. The significance of such studies to such matters as climatic changes, fisheries, commerce, waste disposal, and national defense is noted.

  12. The Circulation of Newly Formed Deep Water in the Atlantic

    NASA Astrophysics Data System (ADS)

    Rhein, M.; Kieke, D.; Steinfeldt, R.

    2012-04-01

    The circulation of newly formed deep water masses (Labrador Sea Water, LSW, and Denmark Strait Overflow Water, DSOW) is examined by discussing the distribution of two parameters (age τ and fraction F of young water) calculated from the chlorofluorocarbon data measured between 1980 and 2005 in the Atlantic. Compared to previous studies, a much larger data set was used with an improved gridding procedure, allowing to resolve the distributions in more detail.

  13. Conservation of circulation in magnetohydrodynamics

    PubMed

    Bekenstein; Oron

    2000-10-01

    We demonstrate at both the Newtonian and (general) relativistic levels the existence of a generalization of Kelvin's circulation theorem (for pure fluids) that is applicable to perfect magnetohydrodynamics. The argument is based on the least action principle for magnetohydrodynamic flow. Examples of the new conservation law are furnished. The new theorem should be helpful in identifying new kinds of vortex phenomena distinct from magnetic ropes or fluid vortices.

  14. Early concepts and charts of ocean circulation

    NASA Astrophysics Data System (ADS)

    Peterson, R. G.; Stramma, L.; Kortum, G.

    in the 1860s and 1870s (i.e. Lightning; Porcupine; Challenger; Gazelle; Vøringen), as well as mounting evidence for the existence of a deep and global thermohaline circulation (Carpenter; Prestwich). The dynamical method for calculating geostrophic flow in the atmosphere (Guldberg and Mohn) and a precursor to our present formulation for quantizing surface wind stress (Zöppritz) were introduced in the 1870s. On a regional scale for the Norwegian Sea, the dynamical method was applied to marine measurements made at depth to yield a three-dimensional view of flow patterns (Mohn). Further insight into the deep circulation came slowly, but with ever increasing numbers of observations being made at and near the surface, the upper-layer circulation in non-polar latitudes was approximately described by the late 1880s (Krümmel).

  15. Understanding and Portraying the Global Atmospheric Circulation.

    ERIC Educational Resources Information Center

    Harrington, John, Jr.; Oliver, John E.

    2000-01-01

    Examines teaching models of atmospheric circulation and resultant surface pressure patterns, focusing on the three-cell model and the meaning of meridional circulation as related to middle and high latitudes. Addresses the failure of the three-cell model to explain seasonal variations in atmospheric circulation. Suggests alternative models. (CMK)

  16. Encoders for block-circulant LDPC codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush (Inventor); Abbasfar, Aliazam (Inventor); Jones, Christopher R. (Inventor); Dolinar, Samuel J. (Inventor); Thorpe, Jeremy C. (Inventor); Andrews, Kenneth S. (Inventor); Yao, Kung (Inventor)

    2009-01-01

    Methods and apparatus to encode message input symbols in accordance with an accumulate-repeat-accumulate code with repetition three or four are disclosed. Block circulant matrices are used. A first method and apparatus make use of the block-circulant structure of the parity check matrix. A second method and apparatus use block-circulant generator matrices.

  17. Some Demographic Correlates of Changing Newspaper Circulation.

    ERIC Educational Resources Information Center

    Eberhard, Wallace B.

    There are varied opinions on the relationship between the circulation penetration of the American daily newspapers and certain demographic indicators. Previous studies have treated the growth of circulation figures by utilizing gross national data and have indicated the role newspaper circulation plays in defining the limits of major urban…

  18. TI-59 Drilling engineering manual. [Texas Instruments-59 Calculator Programs

    SciTech Connect

    Chenevert, M.E.; Hollo, R.

    1981-01-01

    Twenty-seven drilling engineering programs to be used with the Texas Instruments 59 programmable calculator are given, with step-by-step explanations on how to input these on the calculator. Programs for basic drilling engineering, drilling fluid viscosity and circulation, hydrostatic pressure due to gas, surge and swab pressure, and well control are given. (JMT)

  19. Caribbean international circulation: are Puerto Rican women tied-circulators?

    PubMed

    Conway, D; Ellis, M; Shiwdhan, N

    1990-01-01

    Aspects of migration between Puerto Rico and the United States are explored. "This examination of the multiple-movement behaviour of a sample of Puerto Rican women seeks to unravel the relations between their circulation patterns, their family and contextual situations and their declared motives for undertaking international mobility. The leading question asked in this study is whether this international mobility behaviour of Puerto Rican women is autonomous or dependent upon the movement or decision-making of others. Structural theory suggests the latter is most likely, but behavioural divergence occurs in return movement."

  20. HENRY'S LAW CALCULATOR

    EPA Science Inventory

    On-Site was developed to provide modelers and model reviewers with prepackaged tools ("calculators") for performing site assessment calculations. The philosophy behind OnSite is that the convenience of the prepackaged calculators helps provide consistency for simple calculations,...

  1. Numerical study of three-dimensional shelf circulation on the Scotian Shelf using a shelf circulation model

    NASA Astrophysics Data System (ADS)

    Ohashi, Kyoko; Sheng, Jinyu; Thompson, Keith R.; Hannah, Charles G.; Ritchie, Harold

    2009-09-01

    A numerical shelf circulation model was developed for the Scotian Shelf, using a nested-grid setup consisting of a three-dimensional baroclinic inner model embedded inside a two-dimensional barotropic outer model. The shelf circulation model is based on the Princeton Ocean Model and driven by three-hourly atmospheric forcing provided by a numerical weather forecast model and by tidal forcing specified at the inner model's open boundaries based on pre-calculated tidal harmonic constants. The outer model simulates the depth-mean circulation forced by wind and atmospheric pressure fields over the northwest Atlantic Ocean with a horizontal resolution of 1/12°. The inner model simulates the three-dimensional circulation over the Gulf of St. Lawrence, the Scotian Shelf, and the adjacent slope with a horizontal resolution of 1/16°. The performance of the shelf circulation model is assessed by comparing model results with oceanographic observations made along the Atlantic coast of Nova Scotia and in the vicinity of Sable Island (on the Scotian Shelf) during two periods: October 2000-March 2001 and April-June 2002. Analysis of model results on Sable Island Bank indicates that tidal currents account for as much as ˜80% of the total variance of near-bottom currents, and currents driven by local winds account for ˜30% of the variance of the non-tidal near-bottom currents. Shelf waves generated remotely by winds and propagating into the region also play an important role in the near-bottom circulation on the bank.

  2. Matrix-free constructions of circulant and block circulant preconditioners

    SciTech Connect

    Yang, Chao; Ng, Esmond G.; Penczek, Pawel A.

    2001-12-01

    A framework for constructing circulant and block circulant preconditioners (C) for a symmetric linear system Ax=b arising from certain signal and image processing applications is presented in this paper. The proposed scheme does not make explicit use of matrix elements of A. It is ideal for applications in which A only exists in the form of a matrix vector multiplication routine, and in which the process of extracting matrix elements of A is costly. The proposed algorithm takes advantage of the fact that for many linear systems arising from signal or image processing applications, eigenvectors of A can be well represented by a small number of Fourier modes. Therefore, the construction of C can be carried out in the frequency domain by carefully choosing its eigenvalues so that the condition number of C{sup T} AC can be reduced significantly. We illustrate how to construct the spectrum of C in a way such that the smallest eigenvalues of C{sup T} AC overlaps with those of A extremely well while the largest eigenvalues of C{sup T} AC are smaller than those of A by several orders of magnitude. Numerical examples are provided to demonstrate the effectiveness of the preconditioner on accelerating the solution of linear systems arising from image reconstruction application.

  3. Genetic Variants Associated with Circulating Parathyroid Hormone.

    PubMed

    Robinson-Cohen, Cassianne; Lutsey, Pamela L; Kleber, Marcus E; Nielson, Carrie M; Mitchell, Braxton D; Bis, Joshua C; Eny, Karen M; Portas, Laura; Eriksson, Joel; Lorentzon, Mattias; Koller, Daniel L; Milaneschi, Yuri; Teumer, Alexander; Pilz, Stefan; Nethander, Maria; Selvin, Elizabeth; Tang, Weihong; Weng, Lu-Chen; Wong, Hoi Suen; Lai, Dongbing; Peacock, Munro; Hannemann, Anke; Völker, Uwe; Homuth, Georg; Nauk, Matthias; Murgia, Federico; Pattee, Jack W; Orwoll, Eric; Zmuda, Joseph M; Riancho, Jose Antonio; Wolf, Myles; Williams, Frances; Penninx, Brenda; Econs, Michael J; Ryan, Kathleen A; Ohlsson, Claes; Paterson, Andrew D; Psaty, Bruce M; Siscovick, David S; Rotter, Jerome I; Pirastu, Mario; Streeten, Elizabeth; März, Winfried; Fox, Caroline; Coresh, Josef; Wallaschofski, Henri; Pankow, James S; de Boer, Ian H; Kestenbaum, Bryan

    2016-12-07

    Parathyroid hormone (PTH) is a primary calcium regulatory hormone. Elevated serum PTH concentrations in primary and secondary hyperparathyroidism have been associated with bone disease, hypertension, and in some studies, cardiovascular mortality. Genetic causes of variation in circulating PTH concentrations are incompletely understood. We performed a genome-wide association study of serum PTH concentrations among 29,155 participants of European ancestry from 13 cohort studies (n=22,653 and n=6502 in discovery and replication analyses, respectively). We evaluated the association of single nucleotide polymorphisms (SNPs) with natural log-transformed PTH concentration adjusted for age, sex, season, study site, and principal components of ancestry. We discovered associations of SNPs from five independent regions with serum PTH concentration, including the strongest association with rs6127099 upstream of CYP24A1 (P=4.2 × 10(-53)), a gene that encodes the primary catabolic enzyme for 1,25-dihydroxyvitamin D and 25-dihydroxyvitamin D. Each additional copy of the minor allele at this SNP associated with 7% higher serum PTH concentration. The other SNPs associated with serum PTH concentration included rs4074995 within RGS14 (P=6.6 × 10(-17)), rs219779 adjacent to CLDN14 (P=3.5 × 10(-16)), rs4443100 near RTDR1 (P=8.7 × 10(-9)), and rs73186030 near CASR (P=4.8 × 10(-8)). Of these five SNPs, rs6127099, rs4074995, and rs219779 replicated. Thus, common genetic variants located near genes involved in vitamin D metabolism and calcium and renal phosphate transport associated with differences in circulating PTH concentrations. Future studies could identify the causal variants at these loci, and the clinical and functional relevance of these variants should be pursued.

  4. Trend Analysis and Detection of Changes in the Stratospheric Circulation

    NASA Technical Reports Server (NTRS)

    Oman, Luke; Douglass, A. R.; Rodriquez, J. M.; Stolarski, R. S.; Waugh, D. W.

    2010-01-01

    Increases in the circulation of the stratosphere appear to be a robust result of climate change in chemistry-climate models over decadal time scales. To date observations have yet to show a significant change in this circulation. It is important for the design of future observational missions to identify suitable atmospheric constituents and to determine the accuracy and length of record needed to identify a significant trend that can be attributed to circulation change. First, we determine what atmospheric variables can be used as proxies for stratospheric circulation changes. A few examples are changes in tropical lower stratospheric ozone, phase lag of the water vapor tape recorder, CO2, and SF6. Then, using both the Goddard Earth Observing System Chemistry-Climate Model (GEOS CCM) and observations from satellites and balloon soundings, we calculate the number of years needed to detect a significant trend, taking into account observational uncertainty. Model simulations will be evaluated to see how well they represent observed variability. In addition, the impacts of autocorrelation among the output or data and gaps in the observational record will be discussed.

  5. Circulation in Enewetak Atoll lagoon

    SciTech Connect

    Atkinson, M.; Smith, S.V.; Stroup, E.D.

    1981-11-01

    Currents at Enewetak Atoll, Marshall Islands, were measured on the reef margins, in the channels, and in the lagoon. Lagoon circulation is dominated by wind-driven downwind surface flow and an upwind middepth return flow. This wind-driven flow has the characteristics of an Ekman spiral in an enclosed sea. Lagoon flushing is accomplished primarily by surf-driven water input over the windward (eastern) reefs and southerly drift out the South Channel. Mean water residence time is 1 month, while water entering the northern portion of the atoll takes about 4 months to exit.

  6. Isolation and Characterization of Circulating Lymphatic Endothelial Colony Forming Cells

    PubMed Central

    DiMaio, Terri A.; Wentz, Breanna L.; Lagunoff, Michael

    2016-01-01

    Rationale The identification of circulating endothelial progenitor cells has led to speculation regarding their origin as well as their contribution to neovascular development. Two distinct types of endothelium make up the blood and lymphatic vessel system. However, it has yet to be determined whether there are distinct lymphatic-specific circulating endothelial progenitor cells. Objective This study aims to isolate and characterize the cellular properties and global gene expression of lymphatic-specific endothelial progenitor cells. Methods and Results We isolated circulating endothelial colony forming cells (ECFCs) from whole peripheral blood. These cells are endothelial in nature, as defined by their expression of endothelial markers and their ability to undergo capillary morphogenesis in three-dimensional culture. A subset of isolated colonies express markers of lymphatic endothelium, including VEGFR-3 and Prox-1, with low levels of VEGFR-1, a blood endothelial marker, while the bulk of the isolated cells express high VEGFR-1 levels with low VEGFR-3 and Prox-1 expression. The different isolates have differential responses to VEGF-C, a lymphatic endothelial specific cytokine, strongly suggesting that there are lymphatic specific and blood specific ECFCs. Global analysis of gene expression revealed key differences in the regulation of pathways involved in cellular differentiation between blood and lymphatic-specific ECFCs. Conclusion These data indicate that there are two distinguishable circulating ECFC types, blood and lymphatic, which are likely to have discrete functions during neovascularization. PMID:26597759

  7. Roadmap for cardiovascular circulation model.

    PubMed

    Safaei, Soroush; Bradley, Christopher P; Suresh, Vinod; Mithraratne, Kumar; Muller, Alexandre; Ho, Harvey; Ladd, David; Hellevik, Leif R; Omholt, Stig W; Chase, J Geoffrey; Müller, Lucas O; Watanabe, Sansuke M; Blanco, Pablo J; de Bono, Bernard; Hunter, Peter J

    2016-12-01

    Computational models of many aspects of the mammalian cardiovascular circulation have been developed. Indeed, along with orthopaedics, this area of physiology is one that has attracted much interest from engineers, presumably because the equations governing blood flow in the vascular system are well understood and can be solved with well-established numerical techniques. Unfortunately, there have been only a few attempts to create a comprehensive public domain resource for cardiovascular researchers. In this paper we propose a roadmap for developing an open source cardiovascular circulation model. The model should be registered to the musculo-skeletal system. The computational infrastructure for the cardiovascular model should provide for near real-time computation of blood flow and pressure in all parts of the body. The model should deal with vascular beds in all tissues, and the computational infrastructure for the model should provide links into CellML models of cell function and tissue function. In this work we review the literature associated with 1D blood flow modelling in the cardiovascular system, discuss model encoding standards, software and a model repository. We then describe the coordinate systems used to define the vascular geometry, derive the equations and discuss the implementation of these coupled equations in the open source computational software OpenCMISS. Finally, some preliminary results are presented and plans outlined for the next steps in the development of the model, the computational software and the graphical user interface for accessing the model.

  8. Intestinal circulation during inhalation anesthesia

    SciTech Connect

    Tverskoy, M.; Gelman, S.; Fowler, K.C.; Bradley, E.L.

    1985-04-01

    This study was designed to evaluate the influence of inhalational agents on the intestinal circulation in an isolated loop preparation. Sixty dogs were studied, using three intestinal segments from each dog. Selected intestinal segments were pumped with aortic blood at a constant pressure of 100 mmHg. A mixture of /sub 86/Rb and 9-microns spheres labeled with /sup 141/Ce was injected into the arterial cannula supplying the intestinal loop, while mesenteric venous blood was collected for activity counting. A very strong and significant correlation was found between rubidium clearance and microsphere entrapment (r = 0.97, P less than 0.0001). Nitrous oxide anesthesia was accompanied by a higher vascular resistance (VR), lower flow (F), rubidium clearance (Cl-Rb), and microspheres entrapment (Cl-Sph) than pentobarbital anesthesia, indicating that the vascular bed in the intestinal segment was constricted and flow (total and nutritive) decreased. Halothane, enflurane, and isoflurane anesthesia were accompanied by a much lower arteriovenous oxygen content difference (AVDO/sub 2/) and oxygen uptake than pentobarbital or nitrous oxide. Compared with pentobarbital, enflurane anesthesia was not accompanied by marked differences in VR, F, Cl-Rb, and Cl-Sph; halothane at 2 MAC decreased VR and increased F and Cl-Rb while isoflurane increased VR and decreased F. alpha-Adrenoceptor blockade with phentolamine (1 mg . kg-1) abolished isoflurane-induced vasoconstriction, suggesting that the increase in VR was mediated via circulating catecholamines.

  9. Metastasis and Circulating Tumor Cells

    PubMed Central

    van Dalum, Guus; Holland, Linda

    2012-01-01

    Cancer is a prominent cause of death worldwide. In most cases, it is not the primary tumor which causes death, but the metastases. Metastatic tumors are spread over the entire human body and are more difficult to remove or treat than the primary tumor. In a patient with metastatic disease, circulating tumor cells (CTCs) can be found in venous blood. These circulating tumor cells are part of the metastatic cascade. Clinical studies have shown that these cells can be used to predict treatment response and their presence is strongly associated with poor survival prospects. Enumeration and characterization of CTCs is important as this can help clinicians make more informed decisions when choosing or evaluating treatment. CTC counts are being included in an increasing number of studies and thus are becoming a bigger part of disease diagnosis and therapy management. We present an overview of the most prominent CTC enumeration and characterization methods and discuss the assumptions made about the CTC phenotype. Extensive CTC characterization of for example the DNA, RNA and antigen expression may lead to more understanding of the metastatic process. PMID:27683421

  10. A blood circulation model for reference man

    SciTech Connect

    Leggett, R.W.; Eckerman, K.F.; Williams, L.R.

    1999-01-01

    This paper describes a dynamic blood circulation model that predicts the movement and gradual dispersal of a bolus of material in the circulation after its intravascular injection into an adult human. The main purpose of the model is to improve the dosimetry of internally deposited radionuclides that decay in the circulation to a significant extent. The total blood volume is partitioned into the blood contents of 24 separate organs or tissues, right heart chambers, left heart chambers, pulmonary circulation, arterial outflow to the systemic tissues (aorta and large arteries), and venous return from the systemic tissues (large veins). As a compromise between physical reality and computational simplicity, the circulation of blood is viewed as a system of first-order transfers between blood pools, with the delay time depending on the mean transit time across the pool. The model allows consideration of incomplete, tissue-dependent extraction of material during passage through the circulation and return of material from tissues to plasma.

  11. Fractal analysis of circulating platelets in type 2 diabetic patients.

    PubMed

    Bianciardi, G; Tanganelli, I

    2015-01-01

    This paper investigates the use of computerized fractal analysis for objective characterization by means of transmission electron microscopy of the complexity of circulating platelets collected from healthy individuals and from type 2 diabetic patients, a pathologic condition in which platelet hyperreactivity has been described. Platelet boundaries were extracted by means of automatically image analysis. Local fractal dimension by box counting (measure of geometric complexity) was automatically calculated. The results showed that the platelet boundary observed by electron microscopy is fractal and that the shape of the circulating platelets is significantly more complex in the diabetic patients in comparison to healthy subjects (p <  0.01), with 100% correct classification. In vitro activated platelets from healthy subjects show an analogous increase of geometric complexity. Computerized fractal analysis of platelet shape by transmission electron microscopy can provide accurate, quantitative, data to study platelet activation in diabetes mellitus.

  12. Vascular access for extracorporeal circulation. Resistance in double lumen cannulas.

    PubMed

    Stroud, C C; Meyer, S L; Bawkon, M C; Smith, H G; Klein, M D

    1991-01-01

    Double lumen catheters (DLCs) currently are being used for vascular access with extracorporeal circulation. Blood flow studies were done on various DLCs connected to a circuit made of polyvinyl chloride tubing. Sheep's blood was used with all catheters at flows of 200 and 400 ml/min. The inlet and outlet pressures were measured and resistances calculated. Modified versions of the Shiley and Kendall catheters, also were tested. In both catheters, resistance was reduced with the use of perfusion adaptors. Flow through catheters, with a diameter that exceeded the Luer fitting dimension, was compromised. The modified Shiley and unmodified Kendall catheters had the lowest resistance to flow, and they thus are best suited for extracorporeal circulation.

  13. Linear thermal circulator based on Coriolis forces.

    PubMed

    Li, Huanan; Kottos, Tsampikos

    2015-02-01

    We show that the presence of a Coriolis force in a rotating linear lattice imposes a nonreciprocal propagation of the phononic heat carriers. Using this effect we propose the concept of Coriolis linear thermal circulator which can control the circulation of a heat current. A simple model of three coupled harmonic masses on a rotating platform permits us to demonstrate giant circulating rectification effects for moderate values of the angular velocities of the platform.

  14. A blood circulation model for reference man

    SciTech Connect

    Leggett, R.W.; Eckerman, K.F.; Williams, L.R.

    1996-12-31

    A dynamic blood circulation model that predicts the movement and gradual dispersion of a bolus of material in the circulation after its intravenous injection into an adult human. The main purpose of the model is improve the dosimetry of internally deposited radionuclides that decay in the circulation to a significant extent. The model partitions the blood volume into 24 separate organs or tissues, right heart chamber, left heart chamber, pulmonary circulation, arterial outflow to the aorta and large arteries, and venous return via the large veins. Model results were compared to data obtained from injection of carbon 11 labeled carbon monoxide or rubidium 86.

  15. Global atmospheric circulation statistics: Four year averages

    NASA Technical Reports Server (NTRS)

    Wu, M. F.; Geller, M. A.; Nash, E. R.; Gelman, M. E.

    1987-01-01

    Four year averages of the monthly mean global structure of the general circulation of the atmosphere are presented in the form of latitude-altitude, time-altitude, and time-latitude cross sections. The numerical values are given in tables. Basic parameters utilized include daily global maps of temperature and geopotential height for 18 pressure levels between 1000 and 0.4 mb for the period December 1, 1978 through November 30, 1982 supplied by NOAA/NMC. Geopotential heights and geostrophic winds are constructed using hydrostatic and geostrophic formulae. Meridional and vertical velocities are calculated using thermodynamic and continuity equations. Fields presented in this report are zonally averaged temperature, zonal, meridional, and vertical winds, and amplitude of the planetary waves in geopotential height with zonal wave numbers 1-3. The northward fluxes of sensible heat and eastward momentum by the standing and transient eddies along with their wavenumber decomposition and Eliassen-Palm flux propagation vectors and divergences by the standing and transient eddies along with their wavenumber decomposition are also given. Large interhemispheric differences and year-to-year variations are found to originate in the changes in the planetary wave activity.

  16. Uranus atmospheric dynamics and circulation

    NASA Technical Reports Server (NTRS)

    Allison, Michael; Beebe, Reta F.; Conrath, Barney J.; Hinson, David P.; Ingersoll, Andrew P.

    1991-01-01

    The observations, models, and theories relevant to the atmospheric dynamics and meteorology of Uranus are discussed. The available models for the large-scale heat transport and atmospheric dynamics as well as diagnostic interpretations of the Voyager data are reviewed. Some pertinent ideas and questions regarding the global circulation balance are considered, partly in comparison with other planetary atmospheres. The available data indicate atmospheric rotation at midlatitudes nearly 200 m/s faster than that of the planetary magnetic field. Analysis of the dynamical deformation of the shape and size of isobaric surfaces measured by the Voyager radio-occultation experiment suggests a subrotating equator at comparable altitudes. Infrared temperature retrievals above the cloud deck indicate a smaller equator-to-pole contrast than expected for purely radiative-convective equilibrium, but show local variations implying a latitudinally correlated decrease with altitude in the cloud-tracked wind.

  17. [Circulating tumor cells: liquid biopsy].

    PubMed

    Alix-Panabières, Catherine; Pierga, Jean-Yves

    2014-01-01

    The detection and molecular characterization of circulating tumor cells (CTCs) are one of the most active areas of translational cancer research, with more than 400 clinical studies having included CTCs as a biomarker. The aims of research on CTCs include: a) estimation of the risk for metastatic relapse or metastatic progression (prognostic information); b) stratification and real-time monitoring of therapies; c) identification of therapeutic targets and resistance mechanisms; and d) understanding metastasis development in cancer patients. This review focuses on the technologies used for the enrichment and detection of CTCs. We outline and discuss the current technologies that are based on exploiting the physical and biological properties of CTCs. A number of innovative technologies to improve methods for CTC detection have recently been developed, including CTC microchips, filtration devices, quantitative reverse-transcription PCR assays, and automated microscopy systems. Molecular characterization studies have indicated, however, that CTCs are very heterogeneous, a finding that underscores the need for multiplex approaches to capture all of the relevant CTC subsets. We therefore emphasize the current challenges of increasing the yield and detection of CTCs that have undergone an epithelial-mesenchymal transition. Increasing assay analytical sensitivity may lead, however, to a decrease in analytical specificity (e.g., through the detection of circulating normal epithelial cells). A considerable number of promising CTC detection techniques have been developed in recent years. The analytical specificity and clinical utility of these methods must be demonstrated in large prospective multicenter studies to reach the high level of evidence required for their introduction into clinical practice.

  18. Plasma Circulation in the Magnetosphere

    NASA Technical Reports Server (NTRS)

    Moore, T. E.; Fok, Mei-Ching; Delcourt, D. C.; Slinker, S.; Fedder, J. A.; Buenfil, M.

    2006-01-01

    We investigate the global structure and dynamics of plasma circulation produced by prototypical solar wind disturbances of the interplanetary magnetic field and dynamic pressure. We track the global circulation and energization of solar wind, polar wind, and auroral wind plasmas throughout the magnetosphere, until they precipitate or escape into the downstream solar wind. We use the full equations of motion of the plasma ions within fields produced by a global MHD simulation of the dynamic solar wind interaction. We use the dynamic hot plasma density and Poynting energy flux specified at the inner boundary of the MHD simulation as drivers of conjugate ion outflow fluxes using local empirical relations obtained from the FAST and Polar missions. Birkeland currents computed by the MHD code are used to derive a field-parallel potential drop from a Knight-like relation [as modified by Lyons and Evans, 1980]. This potential drop is applied to each ion as an initial bulk energy, added to a thermal heating driven by the locally incident Poynting flux. The solar wind pressure increase case (B(sub Y) = 5; B(sub z) = 0 nT) produces an immediate substorm owing to compression of pre-existing plasmas. The SB(sub z), interval (embedded in NB(sub z)) produces a substorm after about one hour of development. Both disturbances enhance the auroral wind flux and heavy ion pressure of the magnetosphere substantially, with complex dynamic structuring by auroral acceleration vortexes and dynamic reconnection. Comparisons are made with observations during disturbed periods including the Halloween 2003 super-storm and other periods.

  19. The Martian Upper Atmosphere Circulation

    NASA Astrophysics Data System (ADS)

    Bougher, S. W.; Bell, J. M.; Baird, D. T.; Murphy, J. R.

    2005-08-01

    New Mars spacecraft datasets and 3-D modeling capabilities are emerging to characterize the Mars thermospheric circulation patterns for the first time. Upper atmosphere wind constraints are available from recent aerobraking and Mars Express measurements. Mars Global Surveyor (1997-1999) and Mars Odyssey (2001-2002) Accelerometer datasets obtained during aerobraking operations provide density and temperature distributions over limited local time and latitude regions at lower thermospheric altitudes ( ˜100-160 km) [e.g. Keating et al., 1998; 2002; 2003; Withers et al., 2003]. Latitudinal gradients of these fields (i.e. into the winter polar night) vary greatly with the changing Martian seasons. The winter polar warming features observed serve as a tracer of the strength and variability of the Martian thermospheric wind patterns during solstice conditions [Keating et al., 2003; Bougher et al., 2005].Accelerometer data is also being used to estimate cross-track (zonal) wind speeds in the Mars lower thermosphere ( ˜100-130 km) [Baird et al., 2005], yielding values as large as 300-400 m/sec. Most recently, the Mars Express SPICAM instrument discovered nitric oxide (NO) nightglow spectral features in the γ and δ -bands from limb observations (Ls = 74) [Bertaux et al., 2005]. These observed UV nightglow emissions are brightest in the winter polar night region. The solstice winds required to produce the Mars winter polar warming features are also responsible for transporting dayside produced N and O atoms to the nightside where radiative recombination and UV chemiluminescence occurs. These new dynamical constraints for the Martian upper atmosphere are now investigated using coupled MGCM (NASA Ames) and MTGCM (Michigan) simulations for aphelion (Ls = 90) and perihelion (Ls = 270) conditions appropriate to MGS and Odyssey aerobraking datasets described above. Seasonal variations in the thermospheric circulation, and the underlying mechanisms likely responsible for these

  20. Core Cracking and Hydrothermal Circulation Profoundly Affect Ceres' Geophysical Evolution

    NASA Astrophysics Data System (ADS)

    Neveu, Marc; Desch, Steven J.; Castillo-Rogez, Julie C.

    2014-11-01

    The dwarf planet (1)Ceres is about to be visited by the Dawn spacecraft [1]. In addition to a recent report of water vapor emission [2], observations and models of Ceres suggest that its evolution was shaped by interactions between liquid water and silicate rock [3,4].Hydrothermal processes in a heated core require both fractured rock and liquid. Using a new core cracking model coupled to a thermal evolution code [5], we find volumes of fractured rock always large enough for significant interaction to occur. Therefore, liquid persistence is key. It is favored by antifreezes such as ammonia [4], by silicate dehydration which releases liquid, and by hydrothermal circulation itself, which enhances heat transport into the hydrosphere. The heating effect from silicate hydration seems minor. Hydrothermal circulation can profoundly affect Ceres' evolution: it prevents core dehydration via “temperature resets”, global cooling events lasting ~50 Myr, followed by ~1 Gyr periods during which Ceres' interior is nearly isothermal and its hydrosphere largely liquid. Whether Ceres has experienced such extensive hydrothermalism may be determined through examination of its present-day structure. A large, fully hydrated core (radius 420 km) suggests that extensive hydrothermal circulation prevented core dehydration. A small, dry core (radius 350 km) suggests early dehydration from short-lived radionuclides, with shallow hydrothermalism at best. Intermediate structures with a partially dehydrated core seem ambiguous, compatible both with late partial dehydration without hydrothermal circulation, and with early dehydration with extensive hydrothermal circulation. Thus, gravity measurements by the Dawn orbiter [1] could help discriminate between scenarios for Ceres' evolution.References:[1] Russell C. T. & Raymond C. A. (2011) Sp. Sci. Rev. 163, 3-23.[2] Küppers M. et al. (2014) Nature 505, 525-527.[3] Rivkin A. et al. (2011) Sp. Sci. Rev. 163, 95-116.[4] Castillo-Rogez J. C. & Mc

  1. Distillation Calculations with a Programmable Calculator.

    ERIC Educational Resources Information Center

    Walker, Charles A.; Halpern, Bret L.

    1983-01-01

    Describes a three-step approach for teaching multicomponent distillation to undergraduates, emphasizing patterns of distribution as an aid to understanding the separation processes. Indicates that the second step can be carried out by programmable calculators. (A more complete set of programs for additional calculations is available from the…

  2. Linear Four-Chalcogen Interactions in Radical Cationic and Dicationic Dimers of 1,5-(Dichalcogena)canes: Nature of the Interactions Elucidated by QTAIM Dual Functional Analysis with QC Calculations.

    PubMed

    Hayashi, Satoko; Nagata, Kengo; Otsuki, Shota; Nakanishi, Waro

    2017-03-15

    The dynamic and static nature of extended hypervalent interactions of the (B)E···(A)E···(A)E···(B)E type are elucidated for four center-seven electron interactions (4c-7e) in the radical cationic dimers (1·(+)) and 4c-6e in the dicationic dimers (1(2+)) of 1,5-(dichalcogena)canes (2: (A)E(CH2CH2CH2)2(B)E: (A)E, (B)E = S, Se, Te, and O). The quantum theory of atoms-in-molecules dual functional analysis (QTAIM-DFA) is applied for the analysis. Total electron energy densities Hb(rc) are plotted versus Hb(rc) - Vb(rc)/2 [= (ℏ(2)/8m)∇(2)ρb(rc)] at bond critical points (BCPs) of the interactions, where Vb(rc) values show potential energy densities at BCPs. Data from the fully optimized structures correspond to the static nature of the interactions. Those from the perturbed structures around the fully optimized ones are also plotted, in addition to those of the fully optimized ones, which represent the dynamic nature of interactions. The (B)E···(A)E-(A)E···(B)E interactions in 1(2+) are stronger than the corresponding ones in 1·(+), respectively. On the one hand, for 1(2+) with (A)E, (B)E = S, Se, and Te, (A)E···(A)E are all classified by the shared shell interactions and predicted to have the weak covalent nature, except for those in 1a(2+) ((A)E = (B)E = S) and 1d(2+) ((A)E = (B)E = Se), which have the nature of regular closed shell (r-CS)/trigonal bipyramidal adduct formation through charge transfer (CT-TBP). On the other hand, (A)E···(B)E are predicted to have the nature of r-CS/molecular complex formation through charge transfer for 1a(2+), 1b(2+) ((A)E = Se; (B)E = S), and 1d(2+) or r-CS/CT-TBP for 1c(2+) ((A)E = Te; (B)E = S), 1e(2+) ((A)E = Te; (B)E = Se), and 1f(2+) ((A)E = (B)E = Te). The (B)E···(A)E-(A)E···(B)E interactions in 1·(+) and 1(2+) are well-analyzed by applying QTAIM-DFA.

  3. Programmable calculator stress analysis

    SciTech Connect

    Van Gulick, L.A.

    1983-01-01

    Advanced programmable alphanumeric calculators are well suited for closed-form calculation of pressure-vessel stresses. They offer adequate computing power, portability, special programming features, and simple interactive execution procedures. Representative programs that demonstrate calculator capabilities are presented. Problems treated are stress and strength calculations in thick-walled pressure vessels and the computation of stresses near head/pressure-vessel junctures.

  4. Numerical analysis of seawater circulation in carbonate platforms: I. Geothermal convection

    USGS Publications Warehouse

    Sanford, W.E.; Whitaker, F.F.; Smart, P.L.; Jones, G.

    1998-01-01

    Differences in fluid density between cold ocean water and warm ground water can drive the circulation of seawater through carbonate platforms. The circulating water can be the major source of dissolved constituents for diagenetic reactions such as dolomitization. This study was undertaken to investigate the conditions under which such circulation can occur and to determine which factors control both the flux and the patterns of fluid circulation and temperature distribution, given the expected ranges of those factors in nature. Results indicate that the magnitude and distribution of permeability within a carbonate platform are the most important parameters. Depending on the values of horizontal and vertical permeability, heat transport within a platform can occur by one of three mechanisms: conduction, forced convection, or free convection. Depth-dependent relations for porosity and permeability in carbonate platforms suggest circulation may decrease rapidly with depth. The fluid properties of density and viscosity are controlled primarily by their dependency on temperature. The bulk thermal conductivity of the rocks within the platform affects the conductive regime to some extent, especially if evaporite minerals are present within the section. Platform geometry has only a second-order effect on circulation. The relative position of sealevel can create surface conditions that range from exposed (with a fresh-water lens present) to shallow water (with hypersaline conditions created by evaporation in constricted flow conditions) to submerged or drowned (with free surface water circulation), but these boundary conditions and associated ocean temperature profiles have only a second-order effect on fluid circulation. Deep, convective circulation can be caused by horizon tal temperature gradients and can occur even at depths below the ocean bottom. Temperature data from deep holes in the Florida and Bahama platforms suggest that geothermal circulation is actively

  5. Public Library Automation Report: Circulation [and] Appendix.

    ERIC Educational Resources Information Center

    Gotanda, Masae; And Others

    An online circulation system--ULISYS (the Universal Library System Ltd.) manufactured by Digital Equipment Corporation (DEC)--is being installed in the Hawaii State Library, Kaneohe Regional Library, Kailua Community Library and Waimanalo Community/School Library. These libraries are the first users of a statewide online circulation system…

  6. Laptop Circulation at Eastern Washington University

    ERIC Educational Resources Information Center

    Munson, Doris; Malia, Elizabeth

    2008-01-01

    In 2001, Eastern Washington University's Libraries began a laptop circulation program with seventeen laptops. Today, there are 150 laptops in the circulation pool, as well as seventeen digital cameras, eleven digital handycams, and thirteen digital projectors. This article explains how the program has grown to its present size, the growing pains…

  7. Downhole material injector for lost circulation control

    DOEpatents

    Glowka, D.A.

    1991-01-01

    This invention is comprised of an apparatus and method for simultaneously and separately emplacing two streams of different materials through a drillstring in a borehole to a downhole location for lost circulation control. The two streams are mixed outside the drillstring at the desired downhole location and harden only after mixing for control of a lost circulation zone.

  8. Downhole material injector for lost circulation control

    DOEpatents

    Glowka, D.A.

    1994-09-06

    Apparatus and method are disclosed for simultaneously and separately emplacing two streams of different materials through a drill string in a borehole to a downhole location for lost circulation control. The two streams are mixed outside the drill string at the desired downhole location and harden only after mixing for control of a lost circulation zone. 6 figs.

  9. Downhole material injector for lost circulation control

    DOEpatents

    Glowka, David A.

    1994-01-01

    Apparatus and method for simultaneously and separately emplacing two streams of different materials through a drillstring in a borehole to a downhole location for lost circulation control. The two streams are mixed outside the drillstring at the desired downhole location and harden only after mixing for control of a lost circulation zone.

  10. From the discovery of the circulation of the blood to the first steps in hemorheology: part 1.

    PubMed

    Martins e Silva, J

    2009-11-01

    In this article (the first of two on the subject) a brief historical review is presented of the prevailing ideas on the nature of the blood and its circulation from antiquity to the 16th century, when the problem was solved by William Harvey. On the basis of vivisection of various types of animals, Harvey constructed a general and logical model for the whole systemic circulation, which contradicted previous concepts, mainly those that had been put forward by Galen fourteen centuries before. The influence that Galen still exercised on virtually all areas of medicine justified Harvey's hesitations and scruples, forcing him to delay publishing his conclusions for thirteen years. It also explains the controversy with fellow physicians on the subject, which continued until his death. However, through careful observation and painstaking investigation, Harvey demonstrated clearly that the heart was the central organ of the circulatory system, on which depended the propulsion of the blood to the arteries and its subsequent return by different vessels, the veins, to its starting point. The blood coming from the heart was different from that which returned to the organ, the difference (in color and fluidity) being attributed to the presence of constituents which nourished the organism it irrigated. Harvey characterized blood pulsation as the result of the arteries filling with arterial blood during each heart contraction. He demonstrated that the arterial blood left the heart by contraction of the left ventricle, which happened simultaneously with contraction of the right ventricle and, in both, after the contraction of the atria. He confirmed that blood passed through the lung circulation from the right ventricle to the left atrium and from there to the left ventricle. By calculating the volume of blood pumped daily by the heart, Harvey reasoned that the blood could not be consumed by the body and would have to circulate continually through the heart and vascular network

  11. Nature/culture/seawater.

    PubMed

    Helmreich, Stefan

    2011-01-01

    Seawater has occupied an ambiguous place in anthropological categories of "nature" and "culture." Seawater as nature appears as potentiality of form and uncontainable flux; it moves faster than culture - with culture frequently figured through land-based metaphors - even as culture seeks to channel water's (nature's) flow. Seawater as culture manifests as a medium of pleasure, sustenance, travel, disaster. I argue that, although seawater's qualities in early anthropology were portrayed impressionistically, today technical, scientific descriptions of water's form prevail. For example, processes of globalization - which may also be called "oceanization" - are often described as "currents," "flows," and "circulations." Examining sea-set ethnography, maritime anthropologies, and contemporary social theory, I propose that seawater has operated as a “theory machine” for generating insights about human cultural organization. I develop this argument with ethnography from the Sargasso Sea and in the Sea Islands. I conclude with a critique of appeals to water's form in social theory.

  12. Characterization of calculation of in-situ retardation factors of contaminant transport using naturally-radionuclides and rock/water interaction occurring U-Series disequilibria timescales. 1997 annual progress report

    SciTech Connect

    Roback, R.; Murrel, M.; Goldstein, S.; Ku, T.L.; Luo, S.

    1997-01-01

    'The research is directed toward a quantitative assessment of contaminant transport rates in fracture-rock systems using uranium-series radionuclides. Naturally occurring uranium-and thorium-series radioactive disequilibria will provide information on the rates of adsorption-desorption and transport of radioactive contaminants as well as on fluid transport and rock dissolution in a natural setting. This study will also provide an improved characterization of preferential flow and contaminant transport at the Idaho Environmental and Engineering Lab. (INEEL) site. To a lesser extent, the study will include rocks in the unsaturated zone. The authors will produce a realistic model of radionuclide migration under unsaturated and saturated field conditions at the INEEL site, taking into account the retardation processes involved in the rock/water interaction. The major tasks are to (1) determine the natural distribution of U, Th, Pa and Ra isotopes in rock minerals. sorbed phases on the rocks, and in fluids from both saturated and unsaturated zones at the site, and (2) study rock/water interaction processes using U/Th series disequilibrium and a statistical analysis-based model for the Geologic heterogeneity plays an important role in transporting contaminants in fractured rocks. Preferential flow paths in the fractured rocks act as a major pathway for transport of radioactive contaminants in groundwaters. The weathering/dissolution of rock by groundwater also influences contaminant mobility. Thus, it is important to understand the hydrogeologic features of the site and their impact on the migration of radioactive contaminants. In this regard, quantification of the rock weathering/dissolution rate and fluid residence time from the observed decay-series disequilibria will be valuable. By mapping the spatial distribution of the residence time of groundwater in fractured rocks, the subsurface preferential flow paths (with high rock permeability and short fluid residence

  13. Physiology of the fetal and transitional circulation.

    PubMed

    Finnemore, Anna; Groves, Alan

    2015-08-01

    The fetal circulation is an entirely transient event, not replicated at any point in later life, and functionally distinct from the pediatric and adult circulations. Understanding of the physiology of the fetal circulation is vital for accurate interpretation of hemodynamic assessments in utero, but also for management of circulatory compromise in premature infants, who begin extrauterine life before the fetal circulation has finished its maturation. This review summarizes the key classical components of circulatory physiology, as well as some of the newer concepts of physiology that have been appreciated in recent years. The immature circulation has significantly altered function in all aspects of circulatory physiology. The mechanisms and significance of these differences are also discussed, as is the impact of these alterations on the circulatory transition of infants born prematurely.

  14. A method to predict circulation control noise

    NASA Astrophysics Data System (ADS)

    Reger, Robert W.

    Underwater vehicles suffer from reduced maneuverability with conventional lifting append-\\ ages due to the low velocity of operation. Circulation control offers a method to increase maneuverability independent of vehicle speed. However, with circulation control comes additional noise sources, which are not well understood. To better understand these noise sources, a modal-based prediction method is developed, potentially offering a quantitative connection between flow structures and far-field noise. This method involves estimation of the velocity field, surface pressure field, and far-field noise, using only non-time-resolved velocity fields and time-resolved probe measurements. Proper orthogonal decomposition, linear stochastic estimation and Kalman smoothing are employed to estimate time-resolved velocity fields. Poisson's equation is used to calculate time-resolved pressure fields from velocity. Curle's analogy is then used to propagate the surface pressure forces to the far field. This method is developed on a direct numerical simulation of a two-dimensional cylinder at a low Reynolds number (150). Since each of the fields to be estimated are also known from the simulation, a means of obtaining the error from using the methodology is provided. The velocity estimation and the simulated velocity match well when the simulated additive measurement noise is low. The pressure field suffers due to a small domain size; however, the surface pressures estimates fare much better. The far-field estimation contains similar frequency content with reduced magnitudes, attributed to the exclusion of the viscous forces in Curle's analogy. In the absence of added noise, the estimation procedure performs quite nicely for this model problem. The method is tested experimentally on a 650,000 chord-Reynolds-number flow over a 2-D, 20% thick, elliptic circulation control airfoil. Slot jet momentum coefficients of 0 and 0.10 are investigated. Particle image velocimetry, unsteady

  15. Slow and Steady: Ocean Circulation. The Influence of Sea Surface Height on Ocean Currents

    NASA Technical Reports Server (NTRS)

    Haekkinen, Sirpa

    2000-01-01

    The study of ocean circulation is vital to understanding how our climate works. The movement of the ocean is closely linked to the progression of atmospheric motion. Winds close to sea level add momentum to ocean surface currents. At the same time, heat that is stored and transported by the ocean warms the atmosphere above and alters air pressure distribution. Therefore, any attempt to model climate variation accurately must include reliable calculations of ocean circulation. Unlike movement of the atmosphere, movement of the ocean's waters takes place mostly near the surface. The major patterns of surface circulation form gigantic circular cells known as gyres. They are categorized according to their general location-equatorial, subtropical, subpolar, and polar-and may run across an entire ocean. The smaller-scale cell of ocean circulation is known' as an eddy. Eddies are much more common than gyres and much more difficult to track in computer simulations of ocean currents.

  16. The circulation of Levantine intermediate water in the northeastern Ionian sea (late winter/early spring 1986)

    NASA Astrophysics Data System (ADS)

    Theodorou, Athanasios J.

    1991-05-01

    CTD data, collected in the northeastern Ionian Sea during late winter/early spring 1986, are used to examine the spreading of the Levantine Intermediate Water (LIW) on selected isopycnal surfaces. The distribution of salinity on these surfaces provides the qualitative aspects of the flow field. Charts of the spreading of LIW, based on θ-S analysis, emphasize the diffusive nature of the LIW spreading over a major part of the study area. However, more than half of the overall decrease in its concentration, indicative of vertical mixing, occurs at the Strait of Otranto. Geostrophic calculations, with a reference level selected on the basis of heuristic criteria, are used to derive (preserving continuity) the quantitative flow pattern. The circulation of the "upper" water (above the reference level), in the part of the study area south of 37° 30'N was found to be dominated by a mesoscale though distorted anticyclonic gyre; with the latter a total of 2.0 Sv (1 Sv = 1 × 10 6 m 3/s) of "upper" water, including 1.0 Sv of LIW, was found to be associated, presumably re-circulating in the area of the anticyclonic gyre. North of 37°30'N the flow is northward and mildly cyclonic, transporting 0.5 Sv. A major portion of the latter (= 0.4 Sv), including 0.2 Sv of LIW is directed toward the eastern side of the Otranto Strait.

  17. Circulating microparticles: square the circle

    PubMed Central

    2013-01-01

    Background The present review summarizes current knowledge about microparticles (MPs) and provides a systematic overview of last 20 years of research on circulating MPs, with particular focus on their clinical relevance. Results MPs are a heterogeneous population of cell-derived vesicles, with sizes ranging between 50 and 1000 nm. MPs are capable of transferring peptides, proteins, lipid components, microRNA, mRNA, and DNA from one cell to another without direct cell-to-cell contact. Growing evidence suggests that MPs present in peripheral blood and body fluids contribute to the development and progression of cancer, and are of pathophysiological relevance for autoimmune, inflammatory, infectious, cardiovascular, hematological, and other diseases. MPs have large diagnostic potential as biomarkers; however, due to current technological limitations in purification of MPs and an absence of standardized methods of MP detection, challenges remain in validating the potential of MPs as a non-invasive and early diagnostic platform. Conclusions Improvements in the effective deciphering of MP molecular signatures will be critical not only for diagnostics, but also for the evaluation of treatment regimens and predicting disease outcomes. PMID:23607880

  18. RF power recovery feedback circulator

    DOEpatents

    Sharamentov, Sergey I [Bolingbrook, IL

    2011-03-29

    A device and method for improving the efficiency of RF systems having a Reflective Load. In the preferred embodiment, Reflected Energy from a superconducting resonator of a particle accelerator is reintroduced to the resonator after the phase of the Reflected Energy is aligned with the phase of the Supply Energy from a RF Energy Source. In one embodiment, a Circulator is used to transfer Reflected Energy from the Reflective Load into a Phase Adjuster which aligns the phase of the Reflected Energy with that of the Supply Energy. The phase-aligned energy is then combined with the Supply Energy, and reintroduced into the Reflective Load. In systems having a constant phase shift, the Phase Adjuster may be designed to shift the phase of the Reflected Energy by a constant amount using a Phase Shifter. In systems having a variety (variable) phase shifts, a Phase Shifter controlled by a phase feedback loop comprising a Phase Detector and a Feedback Controller to account for the various phase shifts is preferable.

  19. Surface Lander Missions to Mars: Support via Analysis of the NASA Ames Mars General Circulation Model

    NASA Technical Reports Server (NTRS)

    Murphy, James R.; Bridger, Alison F.C.; Haberle, Robert M.

    1997-01-01

    We have characterized the near-surface martian wind environment as calculated with a set of numerical simulations carried out with the NASA Ames Mars General Circulation Model (Mars GCM). These wind environments are intended to offer future spacecraft missions to the martian surface a data base from which to choose those locations which meet the mission's criteria for minimal near surface winds to enable a successful landing. We also became involved in the development and testing of the wind sensor which is currently onboard the Mars-bound Pathfinder lander. We began this effort with a comparison of Mars GCM produced winds with those measured by the Viking landers during their descent through the martian atmosphere and their surface wind measurements during the 3+ martian year lifetime of the mission. Unexpected technical difficulties in implementing the sophisticated Planetary Boundary Layer (PBL) scheme of Haberle et al. (1993) within the Mars GCM precluded our carrying out this investigation with the desired improvement to the model's treatment of the PBL. Thus, our results from this effort are not as conclusive as we had anticipated. As it turns out, similar difficulties have been experienced by other Mars modelling groups in attempting to implement very similar PBL routines into their GCMs (Mars General Circulation Model Intercomparison Workshop, held at Oxford University, United Kingdom, July 22-24, 1996; organized by J. Murphy, J. Hollingsworth, M. Joshi). These problems, which arise due to the nature of the time stepping in each of the models, are near to being resolved at the present. The model discussions which follow herein are based upon results using the existing, less sophisticated PBL routine. We fully anticipate implementing the tools we have developed in the present effort to investigate GCM results with the new PBL scheme implemented, and thereafter producing the technical document detailing results from the analysis tools developed during this

  20. Circulation system of an Antarctic electromechanical bedrock drill

    NASA Astrophysics Data System (ADS)

    Liu, Baolin; Wang, Rusheng; Talalay, Pavel; Wang, Qingyan; Liu, An

    2016-12-01

    For bedrock core drilling below 3000 m in the Antarctic ice sheet, Jilin University has designed a set of modular electromechanical drills with a local reverse circulation system, which works at the bottom of the borehole to remove the rock powder. Thorough removal of the rock powder is critically important to prevent it from accumulating in the bottom of the hole and eventually blocking the drill or causing other problems. During drilling, rock powder is carried by the drilling fluid, which flows from a down-hole pump to the chip chamber. If drilling fluid in the bottom of the hole cannot overcome the flow resistance or if its velocity is too low, the rock powder will not be carried to the chip chamber, and will remain in the borehole or gather in the clearance of the circulation system. Therefore, the down-hole pump performance characteristics are of vital importance. The selection of the down-hole pump for bedrock core drilling should consider both flow rate and outlet pressure. This paper reports a specific calculating method for the rEquired flow rate of the drilling fluid and the pressure losses in the circulation system.

  1. Circulating Omentin-1 and Chronic Painful Temporomandibular Disorder

    PubMed Central

    Harmon, Jennifer B.; Sanders, Anne E.; Wilder, Rebecca S.; Essick, Greg K.; Slade, Gary D.; Hartung, Jane E.; Nackley, Andrea G.

    2016-01-01

    AIMS The biological basis for painful temporomandibular disorder (TMD) remains unclear. An emerging literature implicates circulating inflammatory cytokines in the development of pain sensitivity and painful TMD. One newly discovered anti-inflammatory adipokine, omentin-1, has decreased expression in several inflammatory conditions including osteoarthritis. The aim of this study was to investigate the relationship between omentin-1 levels and painful TMD. METHODS Using a case-control design, chronic painful TMD cases (n=90) and TMD-free controls (n=54) were selected participants in the multisite OPPERA study (Orofacial Pain: Prospective Evaluation and Risk Assessment). Painful TMD case status was determined by examiner using established Research Diagnostic Criteria for TMD. Levels of omentin-1 were measured in stored blood plasma samples using an enzyme-linked immunosorbent assay. Binary logistic regression calculated the odds ratios (ORs) and 95% confidence limits (CLs) for the association between omentin-1 and painful TMD. Models adjusted for study site, age, sex, and body mass index (BMI). RESULTS The unadjusted association between omentin-1 and chronic painful TMD was statistically non-significant (P=.072) Following adjustment of the negative confounding bias of covariates, odds of painful decreased 36% per standard deviation increase in circulating omentin-1 (adjusted OR=0.64, 95% CL: 0.43, 0.96. P=.031). CONCLUSION Circulating levels of omentin-1 were significantly lower in painful TMD cases than controls, suggesting that painful TMD pain is mediated by inflammatory pathways. PMID:27472522

  2. Transport of very short-lived halocarbons from the Indian Ocean to the stratosphere through the Asian monsoon circulation

    NASA Astrophysics Data System (ADS)

    Fiehn, Alina; Hepach, Helmke; Atlas, Elliot; Quack, Birgit; Tegtmeier, Susann; Krüger, Kirstin

    2016-04-01

    Halogenated organic compounds are naturally produced in the ocean and emitted to the atmosphere. The halogenated very short-lived substances (VSLS), such as bromoform, have atmospheric lifetimes of less than half a year. When VSLS reach the stratosphere, they enhance ozone depletion and thus impact the climate. During boreal summer, the Asian monsoon circulation transfers air masses from the Asian troposphere to the global stratosphere. Still, the extent to which VSLS from the Indian Ocean contribute to the stratospheric halogen burden and their exact origin is unclear. Here we show that the monsoon circulation transports VSLS from the Indian Ocean to the stratosphere. During the research cruises SO234-2 and SO235 in July-August 2014 onboard RV SONNE, we measured oceanic and atmospheric concentrations of bromoform (tropical lifetime at 10 km = 17 days), dibromomethane (150 days) and methyl iodide (3.5 days) in the subtropical and tropical West Indian Ocean and calculated their emission strengths. We use the Langrangian transport model FLEXPART driven by ERA-Interim meteorological fields to investigate the transport of oceanic emissions in the atmosphere. We analyze the direct contribution of observed bromoform emissions to the stratospheric halogen budget with forward trajectories. Furthermore, we investigate the connection between the Asian monsoon anticyclone and the oceanic source regions using backward trajectories. The West Indian Ocean is a strong source region of VSLS to the atmosphere and the monsoon transport is fast enough for bromoform to reach the stratosphere. However, the main source regions for the entrainment of oceanic air masses through the Asian monsoon anticyclone are the West Pacific and Bay of Bengal as well as the Arabian Sea. Our findings indicate that changes in emission or circulation in this area due to climate change can directly affect the stratospheric halogen burden and thus the ozone layer.

  3. Molecular Dynamics Calculations

    NASA Technical Reports Server (NTRS)

    1996-01-01

    winning videos in a competition held at the meeting of the American Physical Society's Division of Fluid Dynamics, held in Atlanta, Georgia, in November 1994. Of great interest was the result that in every shock there were a few high-speed precursor particles racing ahead of the shock, carrying information about its impending arrival. Most recently, Dr. Woo has been applying molecular dynamics techniques to the problem of determining the drag produced by the space station truss structure as it flies through the thin residual atmosphere of low-Earth orbit. This problem is made difficult by the complex structure of the truss and by the extreme supersonic nature of the flow. A fully filled section of the truss has already been examined, and drag predictions have been made. Molecular dynamics techniques promise to make realistic drag calculations possible even for very complex partially filled truss segments flying at arbitrary angles.

  4. Tropospheric circulation during the early twentieth century Arctic warming

    NASA Astrophysics Data System (ADS)

    Wegmann, Martin; Brönnimann, Stefan; Compo, Gilbert P.

    2016-04-01

    The early twentieth century Arctic warming (ETCAW) between 1920-1940 is an exceptional feature of climate dynamics in the last century and its warming rate was only recently matched by anthropogenic global warming amplification in the Arctic region. However, atmospheric warming during the ETCAW was strongest in the mid-troposphere and is believed to be triggered by an exceptional case of natural climate variability. Nevertheless, ultimate mechanisms and causes for the ETCAW are still under discussion. Here we use state of the art multi member global circulation models, reanalysis and reconstruction datasets to investigate the internal atmospheric dynamics of the ETCAW. We use these gridded datasets to investigate the role of boreal winter mid-tropospheric heat transport and circulation in providing the energy for the large scale warming. Analysing heat flux components and regional differences, it was found that climate models are not able to reproduce the heat flux evolution shown by reanalysis and reconstruction datasets. These datasets compute an increase of stationary eddy heat flux and a decrease of transient eddy heat flux during the ETCAW. Moreover, tropospheric circulation analysis revealed the important role of both the Atlantic and the Pacific sectors in the convergence of southerly air masses into the Arctic during the warming event. Subsequently, it could be shown that the internal dynamics of the atmosphere played a major role in the formation in the ETCAW.

  5. Cold-Flow Circulating Fluidized-Bed Identification

    SciTech Connect

    Parviz Famouri

    2005-07-01

    In a variety of industrial applications, the use of a circulating fluidized bed (CFB) provides various advantages, such as reducing environmental pollution and increasing process efficiency. The application of circulating fluidized bed technology contributes to the improvement of gas-solid contact, reduction of the cross-sectional area with the use of higher superficial velocities, the use of the solids circulation rate as an additional control variable, and superior radial mixing, Grace et al. [1]. In order to improve raw material usage and utility consumption, optimization and control of CFB is very important, and an accurate, real time model is required to describe and quantify the process. Currently there is no accepted way to construct a reliable model for such a complex CFB system using traditional methods, especially at the pilot or industrial scale. Three major obstacles in characterizing the system are: 1) chaotic nature of the system; 2) non-linearity of the system, and 3) number of immeasurable unknowns internal to the system,[2]. Advanced control theories and methods have the ability to characterize the system, and can overcome all three of these obstacles. These methods will be discussed in this report.

  6. Adhesion receptors as therapeutic targets for circulating tumor cells

    PubMed Central

    Li, Jiahe; King, Michael R.

    2012-01-01

    Metastasis contributes to >90% of cancer-associated mortality. Though primary tumors can be removed by surgical resection or chemo/radiotherapy, metastatic disease is a great challenge to treatment due to its systemic nature. As metastatic “seeds,” circulating tumor cells (CTCs) are believed to be responsible for dissemination from a primary tumor to anatomically distant organs. Despite the possibility of physical trapping of CTCs in microvessels, recent advances have provided insights into the involvement of a variety of adhesion molecules on CTCs. Such adhesion molecules facilitate direct interaction with the endothelium in specific tissues or indirectly through leukocytes. Importantly, significant progress has been made in understanding how these receptors confer enhanced invasion and survival advantage during hematogenous circulation of CTCs through recruitment of macrophages, neutrophils, platelets, and other cells. This review highlights the identification of novel adhesion molecules and how blocking their function can compromise successful seeding and colonization of CTCs in new microenvironment. Encouraged by existing diagnostic tools to identify and isolate CTCs, strategic targeting of these adhesion molecules to deliver conventional chemotherapeutics or novel apoptotic signals is discussed for the neutralization of CTCs in the circulation. PMID:22837985

  7. Tropospheric circulation during the early twentieth century Arctic warming

    NASA Astrophysics Data System (ADS)

    Wegmann, Martin; Brönnimann, Stefan; Compo, Gilbert P.

    2016-06-01

    The early twentieth century Arctic warming (ETCAW) between 1920 and 1940 is an exceptional feature of climate variability in the last century. Its warming rate was only recently matched by recent warming in the region. Unlike recent warming largely attributable to anthropogenic radiative forcing, atmospheric warming during the ETCAW was strongest in the mid-troposphere and is believed to be triggered by an exceptional case of natural climate variability. Nevertheless, ultimate mechanisms and causes for the ETCAW are still under discussion. Here we use state of the art multi-member global circulation models, reanalysis and reconstruction datasets to investigate the internal atmospheric dynamics of the ETCAW. We investigate the role of boreal winter mid-tropospheric heat transport and circulation in providing the energy for the large scale warming. Analyzing sensible heat flux components and regional differences, climate models are not able to reproduce the heat flux evolution found in reanalysis and reconstruction datasets. These datasets show an increase of stationary eddy heat flux and a decrease of transient eddy heat flux during the ETCAW. Moreover, tropospheric circulation analysis reveals the important role of both the Atlantic and the Pacific sectors in the convergence of southerly air masses into the Arctic during the warming event. Subsequently, it is suggested that the internal dynamics of the atmosphere played a major role in the formation in the ETCAW.

  8. Development of a Multi Megawatt Circulator for X Band

    SciTech Connect

    Neilson, J.; Ives, L.; Tantawi, S.G.; /Calabazas Creek Res., Saratoga /SLAC

    2008-03-24

    field on the guide (which minimizes arcing problems) and reduced propensity for mode conversion compared to non-asymmetric circular waveguide modes. Unfortunately, no current designs exist for circulators using the circular TE{sub 01} mode. The basic building block for all low-loss circulators and isolators is a nonreciprocal element with a phase shift dependent on the propagation direction in the guide. Such an element can be constructed by placement of a hollow ferrite rod in a cylindrical waveguide. An inner conductor placed inside the ferrite rod conducts a current pulse that induces an azimuthal magnetic field inside the ferrite. This configuration is depicted in Figure 1a. An alternate configuration using permanent magnets is shown in Figure 1b. Either of these configurations will create a different phase shift for waves propagating in opposite directions along the waveguide axis. This feature can be used to develop a high power circulator. We are currently testing a TE{sub 01} nonreciprocal phase shifter in a 50 MW test stand. This device is in the configuration shown in Figure 1a. The induced differential phase shift and loss will be measured and compared to calculations.

  9. Circulation of prions within dust on a scrapie affected farm.

    PubMed

    Gough, Kevin C; Baker, Claire A; Simmons, Hugh A; Hawkins, Steve A; Maddison, Ben C

    2015-04-16

    Prion diseases are fatal neurological disorders that affect humans and animals. Scrapie of sheep/goats and Chronic Wasting Disease (CWD) of deer/elk are contagious prion diseases where environmental reservoirs have a direct link to the transmission of disease. Using protein misfolding cyclic amplification we demonstrate that scrapie PrP(Sc) can be detected within circulating dusts that are present on a farm that is naturally contaminated with sheep scrapie. The presence of infectious scrapie within airborne dusts may represent a possible route of infection and illustrates the difficulties that may be associated with the effective decontamination of such scrapie affected premises.

  10. The discovery of pulmonary circulation: From Imhotep to William Harvey

    PubMed Central

    ElMaghawry, Mohamed; Zanatta, Alberto; Zampieri, Fabio

    2014-01-01

    In his quest to comprehend his existence, Man has long been exploring his outer world (macro-cosmos), as well as his inner world (micro-cosmos). In modern times, monmental advances in the fields of physics, chemistry, and other natural sciences have reflected on how we understand the anatomy and physiology of the human body and circulation. Yet, humanity took a long and winding road to reach what we acknowledge today as solid facts of cardiovascular physiology. In this article, we will review some of the milestones along this road. PMID:25405183

  11. Personal Finance Calculations.

    ERIC Educational Resources Information Center

    Argo, Mark

    1982-01-01

    Contains explanations and examples of mathematical calculations for a secondary level course on personal finance. How to calculate total monetary cost of an item, monthly payments, different types of interest, annual percentage rates, and unit pricing is explained. (RM)

  12. SpaceX Dragon Air Circulation System

    NASA Technical Reports Server (NTRS)

    Hernandez, Brenda; Piatrovich, Siarhei; Prina, Mauro

    2011-01-01

    The Dragon capsule is a reusable vehicle being developed by Space Exploration Technologies (SpaceX) that will provide commercial cargo transportation to the International Space Station (ISS). Dragon is designed to be a habitable module while it is berthed to ISS. As such, the Dragon Environmental Control System (ECS) consists of pressure control and pressure equalization, air sampling, fire detection, illumination, and an air circulation system. The air circulation system prevents pockets of stagnant air in Dragon that can be hazardous to the ISS crew. In addition, through the inter-module duct, the air circulation system provides fresh air from ISS into Dragon. To utilize the maximum volume of Dragon for cargo packaging, the Dragon ECS air circulation system is designed around cargo rack optimization. At the same time, the air circulation system is designed to meet the National Aeronautics Space Administration (NASA) inter-module and intra-module ventilation requirements and acoustic requirements. A flight like configuration of the Dragon capsule including the air circulation system was recently assembled for testing to assess the design for inter-module and intra-module ventilation and acoustics. The testing included the Dragon capsule, and flight configuration in the pressure section with cargo racks, lockers, all of the air circulation components, and acoustic treatment. The air circulation test was also used to verify the Computational Fluid Dynamics (CFD) model of the Dragon capsule. The CFD model included the same Dragon internal geometry that was assembled for the test. This paper will describe the Dragon air circulation system design which has been verified by testing the system and with CFD analysis.

  13. Snow hydrology in a general circulation model

    NASA Technical Reports Server (NTRS)

    Marshall, Susan; Roads, John O.; Glatzmaier, Gary

    1994-01-01

    A snow hydrology has been implemented in an atmospheric general circulation model (GCM). The snow hydrology consists of parameterizations of snowfall and snow cover fraction, a prognostic calculation of snow temperature, and a model of the snow mass and hydrologic budgets. Previously, only snow albedo had been included by a specified snow line. A 3-year GCM simulation with this now more complete surface hydrology is compared to a previous GCM control run with the specified snow line, as well as with observations. In particular, the authors discuss comparisons of the atmospheric and surface hydrologic budgets and the surface energy budget for U.S. and Canadian areas. The new snow hydrology changes the annual cycle of the surface moisture and energy budgets in the model. There is a noticeable shift in the runoff maximum from winter in the control run to spring in the snow hydrology run. A substantial amount of GCM winter precipitation is now stored in the seasonal snowpack. Snow cover also acts as an important insulating layer between the atmosphere and the ground. Wintertime soil temperatures are much higher in the snow hydrology experiment than in the control experiment. Seasonal snow cover is important for dampening large fluctuations in GCM continental skin temperature during the Northern Hemisphere winter. Snow depths and snow extent show good agreement with observations over North America. The geographic distribution of maximum depths is not as well simulated by the model due, in part, to the coarse resolution of the model. The patterns of runoff are qualitatively and quantitatively similar to observed patterns of streamflow averaged over the continental United States. The seasonal cycles of precipitation and evaporation are also reasonably well simulated by the model, although their magnitudes are larger than is observed. This is due, in part, to a cold bias in this model, which results in a dry model atmosphere and enhances the hydrologic cycle everywhere.

  14. Snow hydrology in a general circulation model

    SciTech Connect

    Marshall, S. ); Roads, J.O. ); Glatzmaier, G. )

    1994-08-01

    A snow hydrology has been implemented in an atmospheric general circulation model (GCM). The snow hydrology consists of parameterizations of snowfall and snow cover fraction, a prognostic calculation of snow temperature, and a model of the snow mass and hydrologic budgets. Previously, only snow albedo had been included. A 3-year GCM simulation with this more complete surface hydrology is compared to a previous GCM control run with the specified snow line, as well as with observations. In particular, the authors discuss comparisons of the atmospheric and surface hydrologic budgets and the surface energy budget for U.S. and Canadian areas. The new snow hydrology changes the annual cycle of the surface moisture and energy budgets in the model. There is a noticeable shift in the runoff maximum from winter in the control run to spring in the snow hydrology run. A substantial amount of GCM winter precipitation is now stored in the seasonal snowpack. Snow cover also acts as an important insulating layer between the atmosphere and the ground. Wintertime soil temperatures are much higher in the snow, hydrology experiment than in the control experiment. Seasonal snow cover is important for dampening large fluctuations in GCM continental skin temperature during the Northern Hemisphere winter. Snow depths and snow extent show good agreement with observations over North America. The geographic distribution of maximum depths is not as well simulated by the model due, in part, to the coarse resolution of the model. The patterns of runoff are qualitatively and quantitatively similar to observed patterns of streamflow averaged over the continental United States. The seasonal cycles of precipitation and evaporation are also reasonably well simulated by the model, although their magnitudes are larger than is observed. This is due, in part, to a cold bias in this model, which results in a dry model atmosphere and enhances the hydrologic cycle everywhere. 52 refs., 13 figs., 5 tabs.

  15. Is Global Warming significantly affecting atmospheric circulation extremes?

    NASA Astrophysics Data System (ADS)

    Sardeshmukh, P. D.; Compo, G. P.; Penland, M. C.

    2012-12-01

    Although the anthropogenic influence on 20th century global warming is well established, the influence on the atmospheric circulation, especially on regional scales at which natural variability is relatively large, has proved harder to ascertain. And yet assertions are often made to this effect, especially in the media whenever an extreme warm or cold or dry or wet spell occurs and is tied to an apparent trend in the large-scale atmospheric circulation pattern. We are addressing this important issue using the longest currently available global atmospheric circulation dataset, an ensemble of 56 equally likely estimates of the atmospheric state within observational error bounds generated for every 6 hours from 1871 to the present in the 20th Century Reanalysis Project (20CR; Compo et al, QJRMS 2011). We previously presented evidence that long-term trends in the indices of several major modes of atmospheric circulation variability, including the North Atlantic Oscillation (NAO) and the tropical Pacific Walker Circulation (PWC), were weak or non-existent over the full period of record in the 20CR dataset. We have since investigated the possibility of a change in the probability density functions (PDFs) of the daily values of these indices, including changes in their tails, from the first to the second halves of the 20th century and found no statistically significant change. This was done taking into account the generally skewed and heavy-tailed character of these PDFs, and using both raw histograms and fitted "SGS" probability distributions (whose relevance in describing large-scale atmospheric variability was demonstrated in Sardeshmukh and Sura, J. Climate 2009) to assess the significance of any changes through extensive Monte Carlo simulations. We stress that without such an explicit accounting of departures from normal distributions, detection and attribution studies of changes in climate extremes may be seriously compromised and lead to wrong conclusions. Our

  16. Venous waterfalls in coronary circulation.

    PubMed

    Gosselin, R E; Kaplow, S M

    1991-03-21

    Several studies of flow through collapsible tubing deformed by external pressures have led to a concept known as the "vascular waterfall". One hallmark of this state is a positive zero-flow pressure intercept (Pe) in flow-pressure curves. This intercept is commonly observed in the coronary circulation, but in blood-perfused beating hearts a vascular waterfall is not the only putative cause. To restrict the possibilities, we have measured flow-pressure curves in excised non-beating rabbit hearts in which the coronary arteries were perfused in a non-pulsatile way with a newtonian fluid (Ringers solution) containing potent vasodilator drugs. Under these circumstances, vascular waterfalls are believed to be the only tenable explanation for Pe. In physical terms the waterfall is a region where the vessel is in a state of partial collapse with a stabilized intraluminal fluid pressure (Pw). It is argued that the most probable site of this collapse was the intramural veins just before they reached the epicardial surface. In accord with the waterfall hypothesis, Pe increased as the heart became more edematous, but flow-pressure curves also became flatter, implying multiple waterfalls with differing Pws, leading to complete collapse of some of the venous channels. The principal compressive force is believed to have been the interstitial fluid pressure as registered through a needle (Pn) implanted in the left ventricular wall, but a small additional force (Ps) was probably due to swelling of interstitial gels. A method is presented for estimating Ps and Pw. Unlike rubber tubing, blood vessels are both collapsible and porous. Apparently because of increased capillary filtration, Pn was found to increase linearly with the perfusion pressure. Thus, Pw was not the same at all points on the flow-pressure curve. This finding has interesting implications with respect to the concept of coronary resistance.

  17. Cerebral circulation during acceleration stress

    NASA Astrophysics Data System (ADS)

    Cirovic, Srdjan

    A mathematical model of the cerebrovascular system has been developed to examine the influence of acceleration on cerebral circulation. The objective is to distinguish the main factors that limit cerebral blood flow in pilots subjected to accelerations which exceed the gravitational acceleration of the earth (Gz > 1). The cerebrovascular system was approximated by an open-loop network of elastic tubes and the flow in blood vessels was modeled according to a one-dimensional theory of flow in collapsible tubes. Since linear analysis showed that the speed of pulse propagation in the intracranial vessels should not be modified by the skull constraint, the same governing equations were used for the intracranial vessels as for the rest of the network. The steady and pulsatile components of the cerebrospinal fluid pressure were determined from the condition that the cranial volume must be conserved. After the qualitative aspects of the model results were verified experimentally, the open-loop geometry was incorporated into a global mathematical model of the cardiovascular system. Both the mathematical models and the experiment show that cerebral blood flow diminishes for Gz > 1 due to an increase in the resistance of the large veins in the neck, which collapse as soon as the venous pressure becomes negative. In contrast, the conservation of the cranial volume requires that the cerebrospinal and venous pressure always be approximately the same, and the vessels contained in the cranial cavity do not collapse. Positive pressure breathing provides protection by elevating blood arterial and venous pressures at the heart, thus preventing the venous collapse and maintaining the normal cerebral vascular resistance.

  18. Circulating immune complexes in asbestos workers

    SciTech Connect

    Zone, J.J.; Rom, W.N.

    1985-08-01

    Circulating immune complexes, rheumatoid factor, and antinuclear antibodies were evaluated in 25 asbestos insulation workers and 32 brick mason controls. There were 10 asbestos workers with radiographic parenchymal or pleural changes, consistent with their asbestos exposure. There were no differences in antinuclear antibodies or rheumatoid factor between asbestos workers and controls. The asbestos workers had significantly increased levels of IgG and IgA circulating immune complexes. There was a significant correlation between IgA circulating immune complexes and radiographic changes.

  19. Encoders for block-circulant LDPC codes

    NASA Technical Reports Server (NTRS)

    Andrews, Kenneth; Dolinar, Sam; Thorpe, Jeremy

    2005-01-01

    In this paper, we present two encoding methods for block-circulant LDPC codes. The first is an iterative encoding method based on the erasure decoding algorithm, and the computations required are well organized due to the block-circulant structure of the parity check matrix. The second method uses block-circulant generator matrices, and the encoders are very similar to those for recursive convolutional codes. Some encoders of the second type have been implemented in a small Field Programmable Gate Array (FPGA) and operate at 100 Msymbols/second.

  20. Geothermal Lost Circulation Zone Mapping Tool

    SciTech Connect

    Bauman, T.J.

    1985-01-01

    Lost circulation is an expensive and often encountered problem when drilling into geothermal formations. A method is needed to more accurately describe loss zones encountered during geothermal drilling to allow for more realistic testing since present testing techniques are inadequate. A Lost Circulation Zone Mapping Tool (LCZMT) is being developed that will quickly locate a loss zone and then provide a visual image of this zone as it intersects the wellbore. A modified Sandia high temperature Acoustic Borehole Televiewer should allow modeling of geothermal loss zones, which would in turn lead to testing that can be performed to evaluate lost circulation materials under simulated downhole conditions. 5 refs., 5 figs.

  1. Calculators, Computers, and Classrooms.

    ERIC Educational Resources Information Center

    Higgins, Jon L.; Kirschner, Vicky

    Suggestions for using four-function calculators, programmable calculators, and microcomputers are considered in this collection of 36 articles. The first section contains articles considering general implications for mathematics curricula implied by the freedom calculators offer students from routine computation, enabling them to focus on results…

  2. Enceladus' Interior: A Liquid Circulation Model

    NASA Astrophysics Data System (ADS)

    Matson, Dennis L.; Johnson, Torrence; Lunine, Jonathan; Castillo-Rogez, Julie

    We are studying a model for Enceladus' interior in which the water, gas, dust and heat are supplied to the plumes by a relatively deeply circulating brine solution. Data indicates such a source for the erupting material. On the basis of ammonia in the plume gas Waite et al. [1] suggested that the jets might originate from a liquid water region under Enceladus' icy surface. Postberg et al. [2] noted that the presence of ". . . grains that are rich in sodium salts (0.5-2 percent by mass). . . can arise only if the plumes originate from liquid water." Waite et al. [1] also regard the some of the plume chemicals as evidence for interactions with an ice layer presumably overlying the liquid water reservoir. They suggest that this could be in the form of dissociation of clathrate hydrates [3]. Additionally, there is a large heat flow of more than 15 GW [4, 5] coming out of Enceladus' south polar region. We consider a model that brings heat and chemical species up to the surface from a reservoir or "ocean" located below the ice crust that may be many tens of kilometers thick. Water transits to the surface via vertical conduits. The Cassini INMS data suggest that the water has a relatively large gas content of order a few percent. As the water travels upward and the pressure is released, exolving gases form bubbles. Since the bubbly liquid is less dense than the ice, it moves upward. (This part of the model is a variant of the "Perrier Ocean" Europa model of Crawford and Stevenson [6]. A similar model was studied for Ganymede by Murchie and Head [7].) Postberg et al. [2] model the plume eruptions that result from the water, gases, salts, and other chemicals that our circulation model provides. In the near-surface reservoir feeding the plumes, bubbles reaching the surface of the water pop and throw a very fine spray. Some of these very small droplets of brine exit with the plume gas and provide the observed salt-rich dust particles [2]. Much of the water-borne heat is

  3. North Atlantic Abyssal Circulation During Heinrich Event 1

    NASA Astrophysics Data System (ADS)

    Burke, A.; Marchal, O.; Francois, R.

    2007-12-01

    Pa-231/Th-230 ratios in three sediment cores from the North Atlantic have been used to infer changes in the meridional overturning circulation (MOC) over the past 20 kyr. The large Pa-231/Th-230 ratios (approaching the production ratio of the two radionuclides in the water column) during Heinrich Event 1 (H1) in core OCE326-GGC5 off of the Bermuda rise have been interpreted in terms of a reduced export of Pa-231 to the Southern Ocean owing to a slow-down of the MOC (McManus et al., Nature, 2004). Similar observations have been found in core SU81-18 from the Iberian continental margin (Gherardi et al., EPSL, 2005). The Pa-231/Th-230 record for core DAPC2 from the Norwegian Sea also has elevated values during H1, although variations in the flux of biogenic opal might be an important factor in controlling Pa-231/Th-230 ratios in the sediment (Hall et al., GRL, 2006). Here we will use an inverse method to combine Pa-231/Th-230 observations for H1 in these three cores with a model of the abyssal circulation in the North Atlantic basin. Two null hypotheses will be tested. The first null hypothesis is that the Pa-231/Th-230 data are consistent with the modern circulation. The second is that these data are consistent with a state of no flow in the abyssal region. In testing each hypothesis, due regard will be given to the uncertainties in both the Pa-231/Th-230 data and the model equations. By comparing the adjustments in the Pa-231/Th-230 values that are necessary to bring them into consistency with the modern circulation (hypothesis 1) and the state of rest (hypothesis 2), insight into the dynamical information contained in these data will be gained.

  4. How Do Calculators Calculate Trigonometric Functions?

    ERIC Educational Resources Information Center

    Underwood, Jeremy M.; Edwards, Bruce H.

    How does your calculator quickly produce values of trigonometric functions? You might be surprised to learn that it does not use series or polynomial approximations, but rather the so-called CORDIC method. This paper will focus on the geometry of the CORDIC method, as originally developed by Volder in 1959. This algorithm is a wonderful…

  5. Wall-to-suspension heat transfer in circulating fluidized beds

    SciTech Connect

    Wirth, K.E.

    1995-12-31

    The wall-to-suspension heat transfer in circulating fluidized beds depends on the fluid mechanics immediately near the wall and on the thermal properties of the gas used. Experimental investigations of circulating fluidized beds of low dimensionless pressure gradients with different solid particles like bronze, glass and polystyrene at ambient temperatures showed no influence of the conductivity and the heat capacity of the solids on the heat transfer coefficient. Consequently the heat transfer coefficient in the form of the dimensionless Nusselt number can be described by the dimensionless numbers which characterize the gas-solid-flow near the wall. These numbers are the Archimedes number and the pressure drop-number. The last number relates the cross-sectional average solids concentration to the solids concentration at minimum fluidization condition. With the aid of a model of segregated vertical gas-solid flow, the flow pattern in the wall region can be calculated and thus the wall heat transfer which depends only on heat conduction in the gas and on the convective heat transfer by the gas. With elevated suspension temperatures, radiation contributes additionally to the heat transfer. When the solids concentration is low, the effect of the radiation on the heat transfer is high. Increasing solids concentration results in a decrease of the radiation effect due to the wall being shielded from the radiation of the hot particles in the core region by the cold solids clusters moving down the wall. A simple correlation is presented for calculating the wall-to-suspension heat transfer in circulating fluidized beds.

  6. Global thermohaline circulation. Part 2: Sensitivity with interactive atmospheric transports

    SciTech Connect

    Wang, X.; Stone, P.H.; Marotzke, J.

    1999-01-01

    A hybrid coupled ocean-atmospheric model is used to investigate the stability of the thermohaline circulation (THC) to an increase in the surface freshwater forcing in the presence of interactive meridional transports in the atmosphere. The ocean component is the idealized global general circulation model used in Part 1. The atmospheric model assumes fixed latitudinal structure of the heat and moisture transports, and the amplitudes are calculated separately for each hemisphere from the large-scale sea surface temperature (SST) and SST gradient, using parameterizations based on baroclinic stability theory. The ocean-atmosphere heat and freshwater exchanges are calculated as residuals of the steady-state atmospheric budgets. Owing to the ocean component`s weak heat transport, the model has too strong a meridional SST gradient when driven with observed atmospheric meridional transports. When the latter are made interactive, the conveyor belt circulation collapses. A flux adjustment is introduced in which the efficiency of the atmospheric transports is lowered to match the too low efficiency of the ocean component. The feedbacks between the THC and both the atmospheric heat and moisture transports are positive, whether atmospheric transports are interactive in the Northern Hemisphere, the Southern Hemisphere, or both. However, the feedbacks operate differently in the northern and southern Hemispheres, because the Pacific THC dominates in the Southern Hemisphere, and deep water formation in the two hemispheres is negatively correlated. The feedbacks in the two hemisphere do not necessarily reinforce each other because they have opposite effects on low-latitude temperatures. The model is qualitatively similar in stability to one with conventional additive flux adjustment, but quantitatively more stable.

  7. Lattice thermal conductivity of TixZryHf1 -x -yNiSn half-Heusler alloys calculated from first principles: Key role of nature of phonon modes

    NASA Astrophysics Data System (ADS)

    Eliassen, Simen N. H.; Katre, Ankita; Madsen, Georg K. H.; Persson, Clas; Løvvik, Ole Martin; Berland, Kristian

    2017-01-01

    In spite of their relatively high lattice thermal conductivity κℓ, the X NiSn (X =Ti , Zr, or Hf) half-Heusler compounds are good thermoelectric materials. Previous studies have shown that κℓ can be reduced by sublattice alloying on the X site. To cast light on how the alloy composition affects κℓ, we study this system using the phonon Boltzmann-transport equation within the relaxation time approximation in conjunction with density functional theory. The effect of alloying through mass-disorder scattering is explored using the virtual crystal approximation to screen the entire ternary TixZryHf1 -x -yNiSn phase diagram. The lowest lattice thermal conductivity is found for the TixHf1 -xNiSn compositions; in particular, there is a shallow minimum centered at Ti0.5Hf0.5NiSn with κℓ taking values between 3.2 and 4.1 W/mK when the Ti content varies between 20% and 80%. Interestingly, the overall behavior of mass-disorder scattering in this system can only be understood from a combination of the nature of the phonon modes and the magnitude of the mass variance. Mass-disorder scattering is not effective at scattering acoustic phonons of low energy. By using a simple model of grain boundary scattering, we find that nanostructuring these compounds can scatter such phonons effectively and thus further reduce the lattice thermal conductivity; for instance, Ti0.5Hf0.5NiSn with a grain size of L =100 nm experiences a 42% reduction of κℓ compared to that of the single crystal.

  8. Synthesis, DFT calculations, electronic structure, electronic absorption spectra, natural bond orbital (NBO) and nonlinear optical (NLO) analysis of the novel 5-methyl-8H-benzo[h]chromeno[2,3-b][1,6] naphthyridine-6(5H),8-dione (MBCND)

    NASA Astrophysics Data System (ADS)

    Halim, Shimaa Abdel; Ibrahim, Magdy A.

    2017-02-01

    New derivative of heteroannulated chromone identified as 5-methyl-8H-benzo[h]chromeno[2,3-b][1,6]naphthyridine-6(5H),8-dione (5, MBCND) was easily and efficiently synthesized from DBU catalyzed condensation reaction of 2-aminochromone-3-carboxaldehyde (1) with 4-hydroxy-1-methylquinolin-2(1H)-one (2). The same product 5 was isolated from condensation reaction of aldeyde 1 with 3-(4-hydroxy-1-methyl-2-oxo-1,2-dihydroquinolin-3-yl)-3-oxopropanoic acid (3) or ethyl 4-(4-hydroxy-1-methyl-2-oxo-1,2-dihydroquinolin-3-yl)-2,4-dioxobutanoate (4). Structure of compound (5, MBCND) was deduced based on their elemental analyses and spectral data (IR, 1H NMR and mass spectra). Density Functional Theory (DFT) calculations at the B3LYP/6-311G (d,p) level of theory have been carried out to investigate the equilibrium geometry of the novel compound (5, MBCND). Moreover, total energy, energy of HOMO and LUMO and Mullikan atomic charges were calculated. In addition, the dipole moment, theoretical study of the electronic structure, nonlinear optical properties (NLO), and natural bonding orbital (NBO) analysis and orientation have been performed and discussed. Also the electronic absorption spectra were measured in polar (methanol) as well as non polar (dioxane) solvents and the assignment of the observed bands has been discussed by TD-DFT calculations. The correspondences between calculated and experimental transitions energies are satisfactory.

  9. Some features of the technology for thermochemical reprocessing of coals in a circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Rokhman, B. B.

    2007-06-01

    Results from theoretical investigations into transfer processes during the combustion of anthracite culm in a circulating fluidized bed furnace are presented. A method is described according to which hot air is separately admitted into the furnace: the primary air, to under the fluidized-bed grate, and the secondary air, to over its upper boundary. Calculation results together with their discussion are presented.

  10. Control of a Circulating Fluidized Bed

    SciTech Connect

    Shim, Hoowang; Rickards, Gretchen; Famouri, Parviz; Turton, Richard; Sams, W. Neal; Koduro, Praveen; Patankar, Amol; Davari, Assad; Lawson, Larry; Boyle, Edward J.

    2001-11-06

    Two methods for optimally controlling the operation of a circulating fluidized bed are being investigated, neural network control and Kalman filter control. The neural network controls the solids circulation rate by adjusting the flow of move air in the non-mechanical valve. Presented is the method of training the neural network from data generated by the circulating fluidized bed (CFB), the results of a sensitivity study indicating that adjusting the move air can control solids flow, and the results of controlling solids circulation rate. The Kalman filter approach uses a dynamic model and a measurement model of the standpipe section of the CFB. Presented are results showing that a Kalman filter can successfully find the standpipe bed height.

  11. Global warming and changes in ocean circulation

    SciTech Connect

    Duffy, P.B.; Caldeira, K.C.

    1998-02-01

    This final report provides an overview of the goals and accomplishments of this project. Modeling and observational work has raised the possibility that global warming may cause changes in the circulation of the ocean. If such changes would occur they could have important climatic consequences. The first technical goal of this project was to investigate some of these possible changes in ocean circulation in a quantitative way, using a state-of -the-art numerical model of the ocean. Another goal was to develop our ocean model, a detailed three-dimensional numerical model of the ocean circulation and ocean carbon cycles. A major non-technical goal was to establish LLNL as a center of excellence in modelling the ocean circulation and carbon cycle.

  12. Analysis of Circulation Controlled Airfoils

    DTIC Science & Technology

    1975-06-01

    NEPS NBPTS KUTTA NAEQN AK HI NT oC <degrees) Re«, N^ N B N. K N Lift coefficient Angle of attack Free stream Reynolds number...BT.RLE.RTE) C INPUT SHOULD BE COMPLETE , i - NPRNT = 0 NLE = NBPTS /2 * 1 PI = 3.141593 TOPI ■ 6.283185 RADEG = 360...5)*DPHi_^~ 4 PCNEPS+J) = <J-1J*DPHI CALCULATE EPSILON DO 5 J=1,NEPS LL = 1 IF (J .GT. 1) LL 5 JJ=LL, NBPTS (Z0( JJ

  13. Aerosol activation: parameterised versus explicit calculation for global models

    NASA Astrophysics Data System (ADS)

    Tost, H.; Pringle, K.; Metzger, S.; Lelieveld, J.

    2009-04-01

    A key process in studies of the aerosol indirect effects on clouds is the activation of particles into droplets at 100% relative humidity. To model this process in cloud, meteorological and climate models is a difficult undertaking because of the wide range of scales involved. The chemical composition of the atmospheric aerosol, originating from both air pollution and natural sources, substantially impacts the aerosol water uptake and growth due to its hygroscopicity. In this study a comparison of aerosol activation, using state-of-the-art aerosol activation parameterisations, and explicit activation due to hygroscopic growth is performed.For that purpose we apply the GMXe aerosol model - treating both dynamic and thermodynamic aerosol properties - within the EMAC (ECHAM5/MESSy Atmospheric chemistry, an atmospheric chemistry general circulation) model. This new aerosol model can explicitely calculate the water uptake of aerosols due to hygroscopicity, allowing the growth of aerosol particles into the regimes of cloud droplets in case of sufficient water vapour availability. Global model simulations using both activation schemes will be presented and compared, elucidating the advantages of each approach.

  14. Estuarine turbidity, flushing, salinity, and circulation

    NASA Technical Reports Server (NTRS)

    Pritchard, D. W.

    1972-01-01

    The effects of estuarine turbidity, flushing, salinity, and circulation on the ecology of the Chesapeake Bay are discussed. The sources of fresh water, the variations in salinity, and the circulation patterns created by temperature and salinity changes are analyzed. The application of remote sensors for long term observation of water temperatures is described. The sources of sediment and the biological effects resulting from increased sediments and siltation are identified.

  15. [Circulating proteinic biomarkers and breast cancer].

    PubMed

    Mathelin, C; Koehl, C; Rio, M-C

    2006-01-01

    Circulating proteinic biomarkers are secreted by tumor cells or by their environmental cells and they have a variable specificity. In case of breast cancer, carcino-embryonic antigen (CEA) was for a long time the only circulating biomarker used. Nowadays, the most useful biomarkers measure circulating levels of fragments of MUC1-polymorphic epithelial mucin (MUC1-PEM): cancer antigen (CA) 15.3, mucin-like carcinoma-associated antigen (MCA), CA 27-29, CA 549... They are useful for general disease follow-up. Other circulating markers belonging to keratins (tissue polypeptide antigen, TPA, TPS or Cyfra 21.1) are correlated with proliferative activity of breast tumors. More recently, the measure of the c-erb B2 circulating part (extra cellular domain, ECD) was proposed as a prognostic biomarker for breast tumors with c-erb B2 overexpression. Moreover, the determination of urinary level of trefoil factor1 (PS2-TFF1) might be useful for the follow-up of hormonodependent breast cancers. The present review describes the clinical interest of these different circulating biomarkers in case of breast cancer, emphasizing their biological characteristics.

  16. Deep Circulation in the South China Sea

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaolong; Zhao, Wei; Xu, Xiaobiao; Tian, Jiwei; Zhou, Chun

    2016-04-01

    The South China Sea (SCS) is the largest marginal sea of the northwest Pacific. The deep circulation in the SCS is investigated on the basis of the Hybrid Coordinate Ocean Model (HYCOM). All the experiments show reasonable agreement with observation from mooring arrays. Analysis of these results provides a detailed spatial structure and temporal variability of the deep circulation in the SCS. The major features of the SCS deep circulation are basin-scale cyclonic gyre and concentrated deep western boundary current (DWBC). The transport of the DWBC is ~2 Sv at 16.5°N with a width of ~53 km. As flowing southwestward, the DWBC becomes weaker with a wider range. Deep upwelling in the SCS is estimated of 0.19 to 1.15 m d-1 with the strongest area around the DWBC. The model results reveal the existence of 80 to 120 days oscillation in the deep northeastern circulation and the DWBC, which are also the areas with large eddy kinetic energy. This seasonal oscillation is northwestward with a velocity amplitude of ~1.0~1.5 cm s-1. The distribution of mixing parameters in the deep SCS plays a role in both spatial structure and volume transport of the deep circulation. Compared with the north shelf of the SCS with the Luzon Strait, deep circulation in the SCS is more sensitive to the large vertical mixing parameters of the Zhongsha Island Chain area.

  17. Sensible and latent heat forced divergent circulations in the West African Monsoon System

    NASA Astrophysics Data System (ADS)

    Hagos, S.; Zhang, C.

    2008-12-01

    Field properties of divergent circulation are utilized to identify the roles of various diabatic processes in forcing moisture transport in the dynamics of the West African Monsoon and its seasonal cycle. In this analysis, the divergence field is treated as a set of point sources and is partitioned into two sub-sets corresponding to latent heat release and surface sensible heat flux at each respective point. The divergent circulation associated with each set is then calculated from the Poisson's equation using Gauss-Seidel iteration. Moisture transport by each set of divergent circulation is subsequently estimated. The results show different roles of the divergent circulations forced by surface sensible and latent heating in the monsoon dynamics. Surface sensible heating drives a shallow meridional circulation, which transports moisture deep into the continent at the polar side of the monsoon rain band and thereby promotes the seasonal northward migration of monsoon precipitation during the monsoon onset season. In contrast, the circulation directly associated with latent heating is deep and the corresponding moisture convergence is within the region of precipitation. Latent heating also induces dry air advection from the north. Neither effect promotes the seasonal northward migration of precipitation. The relative contributions of the processes associated with latent and sensible heating to the net moisture convergence, and hence the seasonal evolution of monsoon precipitation, depend on the background moisture.

  18. Application of circulation classifications from the COST733 collection to the detection of solar and geomagnetic effects on tropospheric circulation over Europe in winter

    NASA Astrophysics Data System (ADS)

    Huth, Radan; Cahynová, Monika; Kyselý, Jan

    2010-05-01

    Many studies of circulation classifications are biased by the fact that they are based on a single classification only; that is, their results are affected by the properties of a particular classification to an unknown extent. A large number of circulation classifications produced and collected in the COST733 database allows such a bias to be removed. As an example, we examine effects of solar activity variations on the frequency of circulation types, making use of more than sixty objective classifications for each of 12 domains, defined over Europe. To determine the solar effects, winter months (December to March) are divided into three classes according to the mean monthly solar activity, within which the frequencies of occurrence of circulation types are calculated. Circulation types coming from any classification with significant differences in frequency between high and low solar activity are identified. Current results generally confirm results of a previous study based on a single classification only (subjective Hess-Brezowsky) that (a) westerly types are more frequent under high than low solar activity; (b) northerly types are more frequent under low than high activity, and (iii) easterly and anticyclonic types are more frequent under low than moderate solar activity; the opposite holds for cyclonic types. The research is supported by the Ministry of Education, Youth, and Sports of the Czech Republic under contract OC115 and the Grant Agency of the Czech Academy of Sciences, project A300420805.

  19. DETECTORS AND EXPERIMENTAL METHODS: Circulation model for water circulation and purification in a water Cerenkov detector

    NASA Astrophysics Data System (ADS)

    Lu, Hao-Qi; Yang, Chang-Gen; Wang, Ling-Yu; Xu, Ji-Lei; Wang, Rui-Guang; Wang, Zhi-Min; Wang, Yi-Fang

    2009-07-01

    Owing to its low cost and good transparency, highly purified water is widely used as a medium in large water Cerenkov detector experiments. The water circulation and purification system is usually needed to keep the water in good quality. In this work, a practical circulation model is built to describe the variation of the water resistivity in the circulation process and compared with the data obtained from a prototype experiment. The successful test of the model makes it useful in the future design and optimization of the circulation/purification system.

  20. Geochemistry and Models of Mantle Circulation

    NASA Astrophysics Data System (ADS)

    Hofmann, A. W.

    1989-07-01

    Geochemical data help to constrain the sizes of identifiable reservoirs within the framework of models of layered or whole-mantle circulation, and they identify the sources of the circulating heterogeneities as mainly crustal and/or lithospheric, but they do not decisively distinguish between different types of circulation. The mass balance between crust, depleted mantle and undepleted mantle based on 143Nd/144Nd, Nb/U and Ce/Pb, and the concentrations of very highly incompatible elements Ba, Rb, Th, U, and K, shows that ca. 25-70% (by mass) of depleted mantle balances the trace element and isotopic abundances of the continental crust. This mass balance reflects the actual proportions of mantle reservoirs only if there are no additional unidentified reservoirs. Evidence on the nature and ages of different source reservoirs comes from the geochemical fingerprints of basalts extruded at mid-ocean ridges and oceanic islands. Consideration of Nd and He isotopes alone indicates that ocean island basalts (OIBS) may be derived from a relatively undepleted portion of the mantle. This has in the past provided a geochemical rationale for a two-layer model consisting of an upper depleted and a lower undepleted (`primitive') mantle layer. However, Pb-isotopic ratios, and Nb/U and Ce/Pb concentration ratios demonstrate that most or all OIB source reservoirs are definitely not primitive. Models consistent with this evidence postulate recycling of oceanic crust and lithosphere or subcontinental lithosphere. Recycling is a natural consequence of mantle convection. This cannot be said for some other models such as those requiring large-scale vertical metasomatism beneath OIB source regions. Unlike other trace elements, Nb, Ta, and Pb discriminate sharply between continental and oceanic crust-forming processes. Because of this, the primitive mantle value of Nb/U = 30 (Ce/Pb = 9) has been fractionated into a continental crustal Nb/U = 12 (Ce/Pb = 4) and a residual-mantle (MORB (mid

  1. Use of JANAF Tables in Equilibrium Calculations and Partition Function Calculations for an Undergraduate Physical Chemistry Course

    ERIC Educational Resources Information Center

    Cleary, David A.

    2014-01-01

    The usefulness of the JANAF tables is demonstrated with specific equilibrium calculations. An emphasis is placed on the nature of standard chemical potential calculations. Also, the use of the JANAF tables for calculating partition functions is examined. In the partition function calculations, the importance of the zero of energy is highlighted.

  2. Multiphase flow calculation software

    DOEpatents

    Fincke, James R.

    2003-04-15

    Multiphase flow calculation software and computer-readable media carrying computer executable instructions for calculating liquid and gas phase mass flow rates of high void fraction multiphase flows. The multiphase flow calculation software employs various given, or experimentally determined, parameters in conjunction with a plurality of pressure differentials of a multiphase flow, preferably supplied by a differential pressure flowmeter or the like, to determine liquid and gas phase mass flow rates of the high void fraction multiphase flows. Embodiments of the multiphase flow calculation software are suitable for use in a variety of applications, including real-time management and control of an object system.

  3. Evapotranspiration Calculator Desktop Tool

    EPA Pesticide Factsheets

    The Evapotranspiration Calculator estimates evapotranspiration time series data for hydrological and water quality models for the Hydrologic Simulation Program - Fortran (HSPF) and the Stormwater Management Model (SWMM).

  4. Calculating Toxic Corridors.

    DTIC Science & Technology

    1980-11-01

    nomograms, and a programmable calculator . Appendices present worksheets, example problems, procedures for determining meteorological inputs, a procedure for determining evaporative source strength, and other items.

  5. Effect of ash circulation in gasification melting system on concentration and leachability of lead in melting furnace fly ash.

    PubMed

    Okada, Takashi; Suzuki, Masaru

    2013-11-30

    In some gasification-melting plants, generated melting furnace fly ash is returned back to the melting furnace for converting the ash to slag. This study investigated the effect of such ash circulation in the gasification-melting system on the concentration and leachability of lead in the melting furnace fly ash. The ash circulation in the melting process was simulated by a thermodynamic calculation, and an elemental analysis and leaching tests were performed on a melting furnace fly ash sample collected from the gasification-melting plant with the ash circulation. It was found that by the ash circulation in the gasification-melting, lead was highly concentrated in the melting furnace fly ash to the level equal to the fly ash from the ash-melting process. The thermodynamic calculation predicted that the lead volatilization by the chlorination is promoted by the ash circulation resulting in the high lead concentration. In addition, the lead extraction from the melting furnace fly ash into a NaOH solution was also enhanced by the ash circulation, and over 90% of lead in the fly ash was extracted in 5 min when using 0.5 mol l(-1) NaOH solution with L/S ratio of 10 at 100 °C. Based on the results, a combination of the gasification-melting with the ash circulation and the NaOH leaching method is proposed for the high efficient lead recovery.

  6. Sensitivity of Age-of-Air Calculations to the Choice of Advection Scheme

    NASA Technical Reports Server (NTRS)

    Eluszkiewicz, Janusz; Hemler, Richard S.; Mahlman, Jerry D.; Bruhwiler, Lori; Takacs, Lawrence L.

    2000-01-01

    -Lagrangian dynamics employed in the MACCM3. This type of dynamical core (employed with a 60-min time step) is likely to reduce SLT's interpolation errors that are compounded by the short-term variability characteristic of the explicit centered-difference dynamics employed in the SKYHI model (time step of 3 min). In the extreme case of a very slowly varying circulation, the choice of advection scheme has no effect on two-dimensional (latitude-height) age-of-air calculations, owing to the smooth nature of the transport circulation in 2D models. These results suggest that nondiffusive schemes may be the preferred choice for multiyear simulations of tracers not overly sensitive to the requirement of monotonicity (this category includes many greenhouse gases). At the same time, age-of-air calculations offer a simple quantitative diagnostic of a scheme's long-term diffusive properties and may help in the evaluation of dynamical cores in multiyear integrations. On the other hand, the sensitivity of the computed ages to the model numerics calls for caution in using age of air as a diagnostic of a GCM's large-scale circulation field.

  7. Effect of circulation on wastewater treatment by Lemna gibba and Lemna minor (floating aquatic macrophytes).

    PubMed

    Demirezen Yilmaz, Dilek; Akbulut, Hatice

    2011-01-01

    In this study, laboratory tests were performed in order to examine growth characteristics of floating aquatic macrophytes (Lemna gibba and Lemna minor) in the presence of wastewater with circulation. The results showed that circulation of the waste water enhanced the kinetics of the process, as compared to the control systems. However, prolonged application of high circulation level had a different effect. In the presence of circulation with aquatic plants, there was additional 85.3-88.2% for BODs and 59.6-66.8% for COD decreases in the water quality indicators. In this study, the effectiveness of L. gibba and L. minor with circulation addition for the removal of four heavy metals (Pb, Ni, Mn, and Cu) from waste water was also investigated. Results from analysis confirmed the accumulation of different metals within the plant and a corresponding decrease of metals in the waste water. At the end of the study of circulation, L. gibba provided the metal removal for Cu, Pb, Ni, and Mn in the waste water as the ratio of 57%, 60%, 60%, and 62%, respectively. In this context, the best results were obtained when the action of L. gibba and L. minor plants, was combined with that of circulation. It is shown that in the presence of L. gibba and L. minor plants that are supplemented with circulation, the national standards of biochemical oxygen demand (BOD5) 27-33 mgL(-1) and chemical oxygen demand (COD) 62-78 mgL(-1) for L. minor and L. gibba, respectively, were reached after treatment. The new results can be used for design calculations regarding expected removal of pollutants by aquatic floating plants.

  8. Testosterone replacement therapy can increase circulating endothelial progenitor cell number in men with late onset hypogonadism.

    PubMed

    Liao, C-H; Wu, Y-N; Lin, F-Y; Tsai, W-K; Liu, S-P; Chiang, H-S

    2013-07-01

    Circulating endothelial progenitor cells (EPCs) are bone marrow-derived cells required for endothelial repair. A low EPC number can be considered as an independent predictor of endothelial dysfunction and future cardiovascular events. Recent evidence shows that patients with hypogonadal symptoms without other confounding risk factors have a low number of circulating progenitor cells (PCs) and EPCs, thus highlighting the role of testosterone in the proliferation and differentiation of EPCs. Here, we investigate if testosterone replacement therapy (TRT) can increase circulating EPC number in men with late onset hypogonadism. Forty-six men (age range, 40-73 years; mean age, 58.3 years) with hypogonadal symptoms were recruited, and 29 men with serum total testosterone (TT) levels less than 350 ng/dL received TRT using transdermal testosterone gel (Androgel; 1% testosterone at 5 g/day) for 12 months. Circulating EPC numbers (per 100 000 monocytes) were calculated using flow cytometry. There was no significant association between serum TT levels and the number of circulating EPCs before TRT. Compared with the number of mean circulating EPCs at baseline (9.5 ± 6.2), the number was significantly higher after 3 months (16.6 ± 11.1, p = 0.027), 6 months (20.3 ± 15.3, p = 0.006) and 12 months (27.2 ± 15.5, p = 0.017) of TRT. Thus, we conclude that serum TT levels before TRT are not significantly associated with the number of circulating EPCs in men with late onset hypogonadism. However, TRT can increase the number of circulating EPCs, which implies the benefit of TRT on endothelial function in hypogonadal men.

  9. Thermohaline residual circulation of the Wadden Sea

    NASA Astrophysics Data System (ADS)

    Burchard, Hans; Badewien, Thomas H.

    2015-12-01

    In this study, we present estuarine circulation driven by horizontal density gradients generated by spatially homogeneous surface buoyancy fluxes over sloping bathymetry as a dynamical feature in the coastal zone being potentially relevant for cross-coastal transports. A combination of downward buoyancy flux (net precipitation, net heating) together with tidal mixing may generate a classical estuarine circulation with landward near-bottom residual currents. The Wadden Sea of the south-eastern North Sea is a prototype for such a coastal regime. It is characterised by extensive inter-tidal flats along the coast separated from the open sea by barrier islands. Here, we present long-term observations from the Wadden Sea covering the years 2006-2011. We investigated the statistics of the density gradients. Typical values for the landward density gradient were ∂ x ρ≈-3ṡ10-5 kg m-4 and maximum values were ∂ x ρ≈-6.5ṡ10-5 kg m-4. The magnitude of the density gradient resulted from the magnitude of the salinity gradient, with some modifications by the positive (towards the coast, in spring) or negative (towards the sea, in autumn) temperature gradient. To explain the generation of estuarine circulation by the surface buoyancy flux, we construct an analytical model representing the geometry and dynamics of a Wadden Sea Basin. With downward buoyancy flux, a weak classical estuarine circulation due to gravitational forcing results, whereas upward buoyancy flux drives inverse estuarine circulation. Finally, a two-dimensional (vertical-longitudinal) numerical model was set up for the idealised geometry, including tidally asymmetric turbulent mixing. This results in significantly stronger estuarine circulation due to the presence of tidal straining. The model assesses the circulation due to neutral and upward surface buoyancy fluxes. We conclude that these mechanisms may be important in many coastal areas and may substantially contribute to coast-to-sea exchange in

  10. [Understanding dosage calculations].

    PubMed

    Benlahouès, Daniel

    2016-01-01

    The calculation of dosages in paediatrics is the concern of the whole medical and paramedical team. This activity must generate a minimum of risks in order to prevent care-related adverse events. In this context, the calculation of dosages is a practice which must be understood by everyone.

  11. Electron beam dose calculations.

    PubMed

    Hogstrom, K R; Mills, M D; Almond, P R

    1981-05-01

    Electron beam dose distributions in the presence of inhomogeneous tissue are calculated by an algorithm that sums the dose distribution of individual pencil beams. The off-axis dependence of the pencil beam dose distribution is described by the Fermi-Eyges theory of thick-target multiple Coulomb scattering. Measured square-field depth-dose data serve as input for the calculations. Air gap corrections are incorporated and use data from'in-air' measurements in the penumbra of the beam. The effective depth, used to evaluate depth-dose, and the sigma of the off-axis Gaussian spread against depth are calculated by recursion relations from a CT data matrix for the material underlying individual pencil beams. The correlation of CT number with relative linear stopping power and relative linear scattering power for various tissues is shown. The results of calculations are verified by comparison with measurements in a 17 MeV electron beam from the Therac 20 linear accelerator. Calculated isodose lines agree nominally to within 2 mm of measurements in a water phantom. Similar agreement is observed in cork slabs simulating lung. Calculations beneath a bone substitute illustrate a weakness in the calculation. Finally a case of carcinoma in the maxillary antrum is studied. The theory suggests an alternative method for the calculation of depth-dose of rectangular fields.

  12. 46 CFR 56.50-45 - Circulating pumps.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Circulating pumps. 56.50-45 Section 56.50-45 Shipping... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-45 Circulating pumps. (a) A main circulating pump and emergency means for circulating water through the main condenser shall be provided....

  13. 46 CFR 56.50-45 - Circulating pumps.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Circulating pumps. 56.50-45 Section 56.50-45 Shipping... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-45 Circulating pumps. (a) A main circulating pump and emergency means for circulating water through the main condenser shall be provided....

  14. 46 CFR 56.50-45 - Circulating pumps.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-45 Circulating pumps. (a) A main circulating pump and emergency means for circulating water through the main condenser shall be provided. The... 46 Shipping 2 2013-10-01 2013-10-01 false Circulating pumps. 56.50-45 Section 56.50-45...

  15. 46 CFR 56.50-45 - Circulating pumps.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-45 Circulating pumps. (a) A main circulating pump and emergency means for circulating water through the main condenser shall be provided. The... 46 Shipping 2 2011-10-01 2011-10-01 false Circulating pumps. 56.50-45 Section 56.50-45...

  16. 46 CFR 56.50-45 - Circulating pumps.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Circulating pumps. 56.50-45 Section 56.50-45 Shipping... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-45 Circulating pumps. (a) A main circulating pump and emergency means for circulating water through the main condenser shall be provided....

  17. Sample size calculations.

    PubMed

    Noordzij, Marlies; Dekker, Friedo W; Zoccali, Carmine; Jager, Kitty J

    2011-01-01

    The sample size is the number of patients or other experimental units that need to be included in a study to answer the research question. Pre-study calculation of the sample size is important; if a sample size is too small, one will not be able to detect an effect, while a sample that is too large may be a waste of time and money. Methods to calculate the sample size are explained in statistical textbooks, but because there are many different formulas available, it can be difficult for investigators to decide which method to use. Moreover, these calculations are prone to errors, because small changes in the selected parameters can lead to large differences in the sample size. This paper explains the basic principles of sample size calculations and demonstrates how to perform such a calculation for a simple study design.

  18. A generic pump/compressor design for circulation of cryogenic fluids

    NASA Astrophysics Data System (ADS)

    Jasinski, T.; Stacy, W. Dodd; Honkonen, S. C.; Sixsmith, H.

    This paper describes the development of a second-generation centrifugal circulator for cryogenic fluids. The circulator is designed to operate over a wide range of flow rate and pressure rise and can be used for the pumping of liquid and compression of vapor at temperatures down to liquid helium (4 K). The machine incorporates self-acting gas journal bearings, a permanent magnet axial thrust bearing, and a variable speed induction motor drive to provide for reliable, maintenance-free operation. Design details of the pump are described. Calculated performance characteristics for a liquid helium pumping application are presented along with a general discussion regarding limitations of the present system.

  19. Vertigo due to posterior circulation stroke.

    PubMed

    Kim, Ji Soo; Lee, Hyung

    2013-07-01

    Stroke in the distribution of the posterior circulation may present as acute onset spontaneous vertigo and imbalance. Although vertigo due to posterior circulation stroke is usually associated with other neurologic symptoms or signs, small infarcts in the cerebellum or brainstem can present with vertigo without other localizing symptoms. Approximately 17% of patients with isolated posterior inferior cerebellar artery territory infarction presented with isolated vertigo, nystagmus, and postural unsteadiness. A head impulse test can differentiate acute isolated vertigo associated with cerebellar stroke from more benign disorders involving the inner ear. Sometimes acute isolated audiovestibular loss can be the initial symptom of impending posterior circulation ischemic stroke (particularly within the territory of the anterior inferior cerebellar artery). In this case, evaluation of isolated audiovestibular loss may prevent the progression of acute vertigo and hearing loss into more widespread areas of infarction in the posterior circulation. In this article, the clinical syndromes and signs of acute vestibular syndrome due to posterior circulation stroke involving the brainstem and cerebellum are summarized.

  20. Modeling meso- and sub-mesoscale circulation along the eastern Crimean coast using numerical calculations

    NASA Astrophysics Data System (ADS)

    Demyshev, S. G.; Evstigneeva, N. A.

    2016-09-01

    A numerical experiment has been carried out using a hydrodynamical model with nonlinear equations of motion and heat and salt advection to reconstruct the fields of hydrophysical parameters taking into account the real atmospheric forcing for the autumn season along the southern coast of the Crimean Peninsula. The studied part of the coast is situated at 44.25°N 33.95°E/44.72°N 34.55°E. High spatial resolution is used for modeling: 350 m in the horizontal plane with 38 layers in the vertical; the bottom topography is described in detail with 500 m resolution. Detected and studied meso- and sub-mesoscale structures in the current field agree well with the observational data, which is impossible or hard to identify in numerical experiments with coarser resolution. Their kinematic characteristics and the lifetime are defined and some mechanisms of their origin are suggested.

  1. Numerical Calculation of Heat Transfer Distribution in a 600Mwe Supercritical Circulating Fluidized Bed Boiler

    NASA Astrophysics Data System (ADS)

    Li, Y.; Li, W. K.; Wu, Y. X.; Yang, H. R.; Nie, L.; Huo, S. S.

    The water wall heat transfer and heat flux distribution in a 600MWe supercritical CFB boiler with water-cooled panel in the furnace was numerically studied. The water wall was made of smooth tube membrane. The solid suspension density ρ, heat flux q and heat transfer coefficient K distribution in the furnace were predicted at rated boiler load (100%BMCR), 75% of turbine heat acceptance load (75% THA) and 50% THA. The results show that for a large-scale CFB boiler, the convection is the main part of heat transfer in the lower furnace, and radiation is the main in the upper lower. The ρ, q and K have the similar axial and radial distributions. Their radial distributions depend on the position of the water wall and boiler load, and show a peak value in the corner. The ρ is a sensitive to K. With increasing of the height in furnace, ρ decreases, thereby the q and K decrease. The radial distributions of q and K are similar at different height. The study shows that the three-dimensional model is valid to predict the heat transfer in the furnace of the 600MWe supercritical CFB boiler.

  2. Proceedings of the Circulation-Control Workshop, 1986

    NASA Technical Reports Server (NTRS)

    Nielsen, Jack N. (Compiler)

    1987-01-01

    A Circulation Control Workshop was held at NASA Ames by respresentatives of academia, industry, and government. A total of 32 papers were given in six technical sessions covering turbulence, circulation control airfoil theory, circulation control airfoil wing experiments, circulation control rotor theory, x-wing technology, fixed wing technology, and other concepts. The last session of the workshop was devoted to circulation control research planning.

  3. Cryogenic hydrogen circulation system of neutron source

    SciTech Connect

    Qiu, Y. N.; Hu, Z. J.; Wu, J. H.; Li, Q.; Zhang, Y.; Zhang, P.; Wang, G. P.

    2014-01-29

    Cold neutron sources of reactors and spallation neutron sources are classic high flux neutron sources in operation all over the world. Cryogenic fluids such as supercritical or supercooled hydrogen are commonly selected as a moderator to absorb the nuclear heating from proton beams. By comparing supercritical hydrogen circulation systems and supercooled hydrogen circulation systems, the merits and drawbacks in both systems are summarized. When supercritical hydrogen circulates as the moderator, severe pressure fluctuations caused by temperature changes will occur. The pressure control system used to balance the system pressure, which consists of a heater as an active controller for thermal compensation and an accumulator as a passive volume controller, is preliminarily studied. The results may provide guidelines for design and operation of other cryogenic hydrogen system for neutron sources under construction.

  4. MAGNETICALLY CONTROLLED CIRCULATION ON HOT EXTRASOLAR PLANETS

    SciTech Connect

    Batygin, Konstantin; Stanley, Sabine; Stevenson, David J.

    2013-10-10

    Through the process of thermal ionization, intense stellar irradiation renders hot Jupiter atmospheres electrically conductive. Simultaneously, lateral variability in the irradiation drives the global circulation with peak wind speeds of the order of ∼km s{sup –1}. In turn, the interactions between the atmospheric flows and the background magnetic field give rise to Lorentz forces that can act to perturb the flow away from its purely hydrodynamical counterpart. Using analytical theory and numerical simulations, we show here that significant deviations away from axisymmetric circulation are unstable in presence of a non-negligible axisymmetric magnetic field. Specifically, our results suggest that dayside-to-nightside flows, often obtained within the context of three-dimensional circulation models, only exist on objects with anomalously low magnetic fields, while the majority of highly irradiated exoplanetary atmospheres are entirely dominated by zonal jets.

  5. A 12 GHz broadband latching circulator

    NASA Astrophysics Data System (ADS)

    Katoh, Y.; Konishi, H.; Sakamoto, K.

    The two kinds of latching circulators, external return path and internal return path, are defined, noting the advantages (faster switching speed, lower switching energy, less complicated fabrication) offered by the internal configuration. It is noted, however, that this kind of circulator is difficult to make broadband because the return paths do not seem to act as part of the ferrite junction. The development of a 12-GHz broadband, internal return path circulator with impedance matching transformer and in-phase adjustment screws designed using eigenvalue measurement is described. In describing the operating characteristics, it is noted that more than 25 dB isolation over 11 GHz to 13.5 GHz and 0.25 dB insertion loss is obtained.

  6. A computational study of circulating large tumor cells traversing microvessels

    PubMed Central

    Kojić, Nikola; Milošević, Miljan; Petrović, Dejan; Isailović, Velibor; Sarioglu, A. Fatih; Haber, Daniel A.; Kojić, Miloš; Toner, Mehmet

    2016-01-01

    Circulating tumor cells (CTCs) are known to be a harbinger of cancer metastasis. The CTCs are known to circulate as individual cells or as a group of interconnected cells called CTC clusters. Since both single CTCs and CTC clusters have been detected in venous blood samples of cancer patients, they needed to traverse at least one capillary bed when crossing from arterial to venous circulation. The diameter of a typical capillary is about 7 μm, whereas the size of an individual CTC or CTC clusters can be greater than 20 μm and thus size exclusion is believed to be an important factor in the capillary arrest of CTCs – a key early event in metastasis. To examine the biophysical conditions needed for capillary arrest, we have developed a custom-built viscoelastic solid–fluid 3D computational model that enables us to calculate, under physiological conditions, the maximal CTC diameter that will pass through the capillary. We show that large CTCs and CTC clusters can successfully cross capillaries if their stiffness is relatively small. Specifically, under physiological conditions, a 13 μm diameter CTC passes through a 7 μm capillary only if its stiffness is less than 500 Pa and conversely, for a stiffness of 10 Pa the maximal passing diameter can be as high as 140 μm, such as for a cluster of CTCs. By exploring the parameter space, a relationship between the capillary blood pressure gradient and the CTC mechanical properties (size and stiffness) was determined. The presented computational platform and the resulting pressure–size–stiffness relationship can be employed as a tool to help study the biomechanical conditions needed for capillary arrest of CTCs and CTC clusters, provide predictive capabilities in disease progression based on biophysical CTC parameters, and aid in the rational design of size-based CTC isolation technologies where CTCs can experience large deformations due to high pressure gradients. PMID:26093786

  7. Measurement of cardiac output from dynamic pulmonary circulation time CT

    SciTech Connect

    Yee, Seonghwan; Scalzetti, Ernest M.

    2014-06-15

    Purpose: To introduce a method of estimating cardiac output from the dynamic pulmonary circulation time CT that is primarily used to determine the optimal time window of CT pulmonary angiography (CTPA). Methods: Dynamic pulmonary circulation time CT series, acquired for eight patients, were retrospectively analyzed. The dynamic CT series was acquired, prior to the main CTPA, in cine mode (1 frame/s) for a single slice at the level of the main pulmonary artery covering the cross sections of ascending aorta (AA) and descending aorta (DA) during the infusion of iodinated contrast. The time series of contrast changes obtained for DA, which is the downstream of AA, was assumed to be related to the time series for AA by the convolution with a delay function. The delay time constant in the delay function, representing the average time interval between the cross sections of AA and DA, was determined by least square error fitting between the convoluted AA time series and the DA time series. The cardiac output was then calculated by dividing the volume of the aortic arch between the cross sections of AA and DA (estimated from the single slice CT image) by the average time interval, and multiplying the result by a correction factor. Results: The mean cardiac output value for the six patients was 5.11 (l/min) (with a standard deviation of 1.57 l/min), which is in good agreement with the literature value; the data for the other two patients were too noisy for processing. Conclusions: The dynamic single-slice pulmonary circulation time CT series also can be used to estimate cardiac output.

  8. A computational study of circulating large tumor cells traversing microvessels.

    PubMed

    Kojić, Nikola; Milošević, Miljan; Petrović, Dejan; Isailović, Velibor; Sarioglu, A Fatih; Haber, Daniel A; Kojić, Miloš; Toner, Mehmet

    2015-08-01

    Circulating tumor cells (CTCs) are known to be a harbinger of cancer metastasis. The CTCs are known to circulate as individual cells or as a group of interconnected cells called CTC clusters. Since both single CTCs and CTC clusters have been detected in venous blood samples of cancer patients, they needed to traverse at least one capillary bed when crossing from arterial to venous circulation. The diameter of a typical capillary is about 7µm, whereas the size of an individual CTC or CTC clusters can be greater than 20µm and thus size exclusion is believed to be an important factor in the capillary arrest of CTCs - a key early event in metastasis. To examine the biophysical conditions needed for capillary arrest, we have developed a custom-built viscoelastic solid-fluid 3D computational model that enables us to calculate, under physiological conditions, the maximal CTC diameter that will pass through the capillary. We show that large CTCs and CTC clusters can successfully cross capillaries if their stiffness is relatively small. Specifically, under physiological conditions, a 13µm diameter CTC passes through a 7µm capillary only if its stiffness is less than 500Pa and conversely, for a stiffness of 10Pa the maximal passing diameter can be as high as 140µm, such as for a cluster of CTCs. By exploring the parameter space, a relationship between the capillary blood pressure gradient and the CTC mechanical properties (size and stiffness) was determined. The presented computational platform and the resulting pressure-size-stiffness relationship can be employed as a tool to help study the biomechanical conditions needed for capillary arrest of CTCs and CTC clusters, provide predictive capabilities in disease progression based on biophysical CTC parameters, and aid in the rational design of size-based CTC isolation technologies where CTCs can experience large deformations due to high pressure gradients.

  9. Natural Xanthones

    NASA Astrophysics Data System (ADS)

    Denisova-Dyatlova, O. A.; Glyzin, V. I.

    1982-10-01

    The available information on the abundance of natural xanthones in nature and the methods for the determination of their structure, biogenesis, and pharmacological properties is surveyed and described systematically. The bibliography includes 151 references.

  10. Dose Calculation Spreadsheet

    SciTech Connect

    Simpkins, Ali

    1997-06-10

    VENTSAR XL is an EXCEL Spreadsheet that can be used to calculate downwind doses as a result of a hypothetical atmospheric release. Both building effects and plume rise may be considered. VENTSAR XL will run using any version of Microsoft EXCEL version 4.0 or later. Macros (the programming language of EXCEL) was used to automate the calculations. The user enters a minimal amount of input and the code calculates the resulting concentrations and doses at various downwind distances as specified by the user.

  11. Available potential energy of the daily coastal circulation at Zadar (Croatia)

    NASA Astrophysics Data System (ADS)

    Trošić, T.; Šinik, N.; Trošić, Ž.

    2006-08-01

    The aim of this study is the evaluation of the sea breeze speed on the basis of its energy. Energetics of the sea breeze can be studied by means of the available potential energy (APE). Part of this energy is transformed into the kinetic energy of the sea breeze. Some similarity exists between the large scale processes of the circulation and the small coastal air circulation due to the fact that both circulations are triggered by the same physics, i.e., solenoidal activity of the baroclinic atmosphere. To evaluate the sea breeze speed, APE was calculated by use of the Lorenz’s equation (1955), and which is possible if the coastal circulation is considered to be a closed system in a hydrostatic equilibrium. For calculations and verifications hourly sea-surface temperatures, near-ground air temperatures and wind speed measurements, as well as the radio-sounding measurements at 12 UTC were used at the Zadar station (ϕ = 44° 08' N, λ = 15° 13' E), which is situated in the central part of the eastern Adriatic coast. Two days with an undisturbed sea breeze circulation were extracted using the methods for minimizing other atmospheric influences. Calculated hourly near ground sea breeze speeds obtained in this way were higher than the measured ones. With the assumption that some of the APE is transformed into the kinetic energy it is possible to obtain characteristic speed of the developed sea breeze with small discrepancies to the near-ground measurements. If 6.6% of the mean daily near ground APE was taken to be transformed to the mean daily kinetic sea breeze energy on the 29th and 4.2% on the 30th September 2002, the best agreement was obtained with the mean daily measured near ground sea breeze speed. This range of values can be attributed to inability to extract precise values for the lapse-rate needed in the APE sea breeze calculations. Results show similarities to the general circulation of the atmosphere, since about 10% of the APE is transformed to the

  12. Jovian Stratospheric Circulation: driven radiatively or mechanically?

    NASA Astrophysics Data System (ADS)

    Zhang, Xi; Shia, Run-Lie; Showman, Adam; Yung, Yuk

    2013-04-01

    The existence of large-scale stratospheric circulation has been hypothesized since the 1990s (e.g., Conrath et al. 1990; West et al. 1992). The evidences come from the recent observations of stratospheric tracers such as hydrogen cyanide (HCN), carbon dioxide (CO2), acetylene (C2H2) and ethane (C2H6) (Lellouch et al. 2006; Nixon et al. 2010). Previous studies (e.g., Friedson et al. 1999; Liang et al. 2005) also proposed that horizontal eddy mixing affects meridional transport processes. But the relative roles of diffusion (eddy-mixing) and advection in the horizontal transport are highly uncertain (Lellouch et al., 2006). On the other hand, whether the stratospheric circulation on Jupiter is induced by differential heating or mechanical forcing from below is still debated (e.g., Conrath et al., 1990; West et al., 1992), because the lower stratosphere of Jupiter might not be purely radiatively controlled (Simon-Miller et al., 2006; Zhang et al., 2012). In order to investigate the circulation pattern in detail, we introduce a two-dimensional photochemical-diffusive-advective model to simulate the distribution of stratospheric hydrocarbons. Analytical solutions are derived to gain the physical insight of the coupled chemical-transport processes, and validate the numerical methods (Zhang et al., 2013). The meridional transport processes are constrained using the latitudinal distributions of C2H2 and C2H6 retrieved from Cassini spacecraft measurements during Jupiter flyby in 2000 (Zhang et al., 2012). The derived residual mean circulation pattern shows inconsistency with the instantaneous zonally averaged radiative forcing map during the Cassini flyby (Zhang, 2012), implying that the lower stratospheric circulation might be partly mechanically driven, as is the case for the Brewer-Dobson circulation on Earth. This research was supported in part by NASA NNX09AB72G grant to the California Institute of Technology. XZ was supported by the Bisgrove Fellowship in the

  13. Reconstructing Ocean Circulation using Coral (triangle)14C Time Series

    SciTech Connect

    Kashgarian, M; Guilderson, T P

    2001-02-23

    the invasion of fossil fuel CO{sub 2} and bomb {sup 14}C into the atmosphere and surface oceans. Therefore the {Delta}{sup 14}C data that are produced in this study can be used to validate the ocean uptake of fossil fuel CO2 in coupled ocean-atmosphere models. This study takes advantage of the quasi-conservative nature of {sup 14}C as a water mass tracer by using {Delta}{sup 14}C time series in corals to identify changes in the shallow circulation of the Pacific. Although the data itself provides fundamental information on surface water mass movement the true strength is a combined approach which is greater than the individual parts; the data helps uncover deficiencies in ocean circulation models and the model results place long {Delta}{sup 14}C time series in a dynamic framework which helps to identify those locations where additional observations are most needed.

  14. An elementary model of money circulation

    NASA Astrophysics Data System (ADS)

    Pokrovskii, Vladimir N.; Schinckus, Christophe

    2016-12-01

    This paper investigates money circulation for a system, consisting of a production system, the government, a central bank, commercial banks and many customers of the commercial banks. A set of equations for the system is written; the theory determines the main features of interaction between production and money circulation. Investigation of the equations in a steady-state situation reveals some relationship among output of the production system and monetary variables. The relation of quantity theory of money is confirmed, whereas a new concept of the efficiency of the system is introduced.

  15. Labour circulation and the urban labour process.

    PubMed

    Standing, G

    1986-01-01

    The author investigates aspects of labor circulation, which he defines as "temporary movement between geographical areas for work or in search of work....[He attempts to determine] what roles have been played by labour circulation in the development of urban-industrial labour forces in the transition to industrial capitalism." Factors considered include the exploitation and oppression of labor migrants; the industrial-urban labor reserve; urban socioeconomic stratification and discrimination by age, sex, or race; the division of labor; and policy options.

  16. Blowing Circulation Control on a Seaplane Airfoil

    NASA Astrophysics Data System (ADS)

    Guo, B. D.; Liu, P. Q.; Qu, Q. L.

    2011-09-01

    RANS simulations are presented for blowing circulation control on a seaplane airfoil. Realizable k-epsilon turbulent model and pressure-based coupled algorithm with second-order discretization were adopted to simulate the compressible flow. Both clear and simple flap configuration were simulated with blowing momentum coefficient Cμ = 0, 0.15 and 0.30. The results show that blowing near the airfoil trailing edge could enhance the Coanda effect, delay the flow separation, and increase the lift coefficient dramatically. The blowing circulation control is promising to apply to taking off and landing of an amphibious aircraft or seaplane.

  17. Interval arithmetic in calculations

    NASA Astrophysics Data System (ADS)

    Bairbekova, Gaziza; Mazakov, Talgat; Djomartova, Sholpan; Nugmanova, Salima

    2016-10-01

    Interval arithmetic is the mathematical structure, which for real intervals defines operations analogous to ordinary arithmetic ones. This field of mathematics is also called interval analysis or interval calculations. The given math model is convenient for investigating various applied objects: the quantities, the approximate values of which are known; the quantities obtained during calculations, the values of which are not exact because of rounding errors; random quantities. As a whole, the idea of interval calculations is the use of intervals as basic data objects. In this paper, we considered the definition of interval mathematics, investigated its properties, proved a theorem, and showed the efficiency of the new interval arithmetic. Besides, we briefly reviewed the works devoted to interval analysis and observed basic tendencies of development of integral analysis and interval calculations.

  18. National Stormwater Calculator

    EPA Pesticide Factsheets

    EPA’s National Stormwater Calculator (SWC) is a desktop application that estimates the annual amount of rainwater and frequency of runoff from a specific site anywhere in the United States (including Puerto Rico).

  19. More Experiments and Calculations.

    ERIC Educational Resources Information Center

    Siddons, J. C.

    1984-01-01

    Describes two experiments that illustrate basic ideas but would be difficult to carry out. Also presents activities and experiments on rainbow cups, electrical charges, electrophorus calculation, pulse electrometer, a skidding car, and on the Oersted effect. (JN)

  20. PHYSICOCHEMICAL PROPERTY CALCULATIONS

    EPA Science Inventory

    Computer models have been developed to estimate a wide range of physical-chemical properties from molecular structure. The SPARC modeling system approaches calculations as site specific reactions (pKa, hydrolysis, hydration) and `whole molecule' properties (vapor pressure, boilin...

  1. Programmable calculator stress analysis

    SciTech Connect

    Van Gulick, L.A.

    1983-01-01

    This paper assesses the suitability of advanced programmable alphanumeric calculators for closed form calculation of pressure vessel stresses and offers, as their advantages, adequate computing power, portability, special programming features, and simple interactive execution procedures. Representative programs which demonstrate their capacities are presented. Problems dealing with stress and strength calculations in thick-walled pressure vessels and with the computation of stresses near head/pressure vessel junctures are treated. Assessed favorably in this paper as useful contributors to computeraided design of pressure vessels, programmable alphanumeric calculators have areas of implementation in checking finite element results, aiding in the development of an intuitive understanding of stresses and their parameter dependencies, and evaluating rapidly a variety of preliminary designs.

  2. Quantum Chemical Calculations

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W.; Arnold, James O. (Technical Monitor)

    1997-01-01

    The current methods of quantum chemical calculations will be reviewed. The accent will be on the accuracy that can be achieved with these methods. The basis set requirements and computer resources for the various methods will be discussed. The utility of the methods will be illustrated with some examples, which include the calculation of accurate bond energies for SiF$_n$ and SiF$_n^+$ and the modeling of chemical data storage.

  3. Source and replica calculations

    SciTech Connect

    Whalen, P.P.

    1994-02-01

    The starting point of the Hiroshima-Nagasaki Dose Reevaluation Program is the energy and directional distributions of the prompt neutron and gamma-ray radiation emitted from the exploding bombs. A brief introduction to the neutron source calculations is presented. The development of our current understanding of the source problem is outlined. It is recommended that adjoint calculations be used to modify source spectra to resolve the neutron discrepancy problem.

  4. How Does the Global-Scale Atmosphere Circulation Produce Clouds?

    NASA Technical Reports Server (NTRS)

    Rossow, William B.

    1999-01-01

    Although clouds are produced by "micro-scale" processes, these processes operate as a response to global-scale atmospheric motions to produce the complex geographic distribution of clouds on Earth. One way to attack this larger-scale problem is to combine global-scale satellite observations of cloud property variations with global-scale determinations of the atmospheric circulation. Such a global data analysis can be used to describe the mean characteristics of clouds and their variations for comparison with global circulation models, to identify systematic relations among observed cloud properties and atmospheric motions, or to estimate, directly, the derivative relations of the processes at work using statistical life-cycle-composites of cloud system evolution. Another approach is to find what characteristics of the global atmospheric circulation are revealed in observed global-scale cloud variations. For the first time this type of analysis is possible with the advent of global, satellite-based cloud (ISCCP), precipitation (microwave-based), and water vapor (merged infrared and microwave) datasets, together with global wind datasets (ECMWF and NCEP re-analyses), all of which resolve features at least down to the upper end of the mesoscale and cover more than a decade. We report on some preliminary attempts to identify quantitative relationships between atmospheric motions and cloud properties that are relevant to cloud processes. Three examples are given: (1) cloud variations at the smallest scales and what they reveal about the nature of small-scale turbulence in the atmospheric boundary layer, (2) cloud variations at "moderate" weather-scales and what they reveal about meteorological storm systems, and (3) cloud variations at the largest scales and what they indicate about interannual variations of climate.

  5. Ocean circulation and properties in Petermann Fjord, Greenland

    NASA Astrophysics Data System (ADS)

    Johnson, H. L.; Münchow, A.; Falkner, K. K.; Melling, H.

    2011-01-01

    The floating ice shelf of Petermann glacier interacts directly with the ocean and is thought to lose at least 80% of its mass through basal melting. Based on three opportunistic ocean surveys in Petermann Fjord we describe the basic oceanography: the circulation at the fjord mouth, the hydrographic structure beneath the ice shelf, the oceanic heat delivered to the under-ice cavity, and the fate of the resulting melt water. The 1100 m deep fjord is separated from neighboring Hall Basin by a sill between 350 and 450 m deep. Fjord bottom waters are renewed by episodic spillover at the sill of Atlantic water from the Arctic. Glacial melt water appears on the northeast side of the fjord at depths between 200 m and that of the glacier's grounding line (about 500 m). The fjord circulation is fundamentally three-dimensional; satellite imagery and geostrophic calculations suggest a cyclonic gyre within the fjord mouth, with outflow on the northeast side. Tidal flows are similar in magnitude to the geostrophic flow. The oceanic heat flux into the fjord appears more than sufficient to account for the observed rate of basal melting. Cold, low-salinity water originating in the surface layer of Nares Strait in winter intrudes far under the ice. This may limit basal melting to the inland half of the shelf. The melt rate and long-term stability of Petermann ice shelf may depend on regional sea ice cover and fjord geometry, in addition to the supply of oceanic heat entering the fjord.

  6. A parallel coupled oceanic-atmospheric general circulation model

    SciTech Connect

    Wehner, M.F.; Bourgeois, A.J.; Eltgroth, P.G.; Duffy, P.B.; Dannevik, W.P.

    1994-12-01

    The Climate Systems Modeling group at LLNL has developed a portable coupled oceanic-atmospheric general circulation model suitable for use on a variety of massively parallel (MPP) computers of the multiple instruction, multiple data (MIMD) class. The model is composed of parallel versions of the UCLA atmospheric general circulation model, the GFDL modular ocean model (MOM) and a dynamic sea ice model based on the Hiber formulation extracted from the OPYC ocean model. The strategy to achieve parallelism is twofold. One level of parallelism is accomplished by applying two dimensional domain decomposition techniques to each of the three constituent submodels. A second level of parallelism is attained by a concurrent execution of AGCM and OGCM/sea ice components on separate sets of processors. For this functional decomposition scheme, a flux coupling module has been written to calculate the heat, moisture and momentum fluxes independent of either the AGCM or the OGCM modules. The flux coupler`s other roles are to facilitate the transfer of data between subsystem components and processors via message passing techniques and to interpolate and aggregate between the possibly incommensurate meshes.

  7. Associations Between South African Rainfall and The General Circulation

    NASA Astrophysics Data System (ADS)

    Tennant, W. J.

    The atmospheric energy cycle, as described by Lorenz, is fundamental to weather and climate. However, the question is how much of the climatic variability can be ascribed to fluctuations in the energy cycle. This study shows that there are indeed strong associations between summer rainfall in central and northern South Africa and the global energy cycle. These associations are manifest through fluctuations in the tropical Hadley circulations, that affect the baroclinicity of the mid-latitudes, that in turn force tropical and sub-tropical circulations. Twice-daily fields from the NCEP/NCAR reanalysis data are used to calculate at- mospheric available potential and kinetic energy and the conversions between these energy forms for mean and eddy components in time and space. Self-organizing maps (SOMs) are used to determine dominant modes within these atmospheric data. The rel- ative frequency of these modes are then assessed for periods of different rainfall char- acteristics. These include, among others, wet and dry seasons and the spatial spread of rainfall. These associations provide insight into the causes of rainfall variability in the African region and open new possibilities in the field of seasonal prediction. If General Circu- lation Models (GCMs) are able to capture fluctuations in the global energy cycle accu- rately, which does seem likely given some preliminary results, more accurate seasonal forecasts may be attempted. This despite the GCMs having difficulty in simulating the smaller-scale motion and associated non-linear interaction.

  8. Money creation and circulation in a credit economy

    NASA Astrophysics Data System (ADS)

    Xiong, Wanting; Fu, Han; Wang, Yougui

    2017-01-01

    This paper presents a multi-agent model describing the main mechanisms of money creation and money circulation in a credit economy. Our special attention is paid to the role of debt in the two processes. With the agent-based modeling approach, macro phenomena are well founded in micro-based causalities. A hypothetical economy composed of a banking system and multiple traders is proposed. Instead of being a pure financial intermediary, the banking system is viewed as the center of money creation and an accelerator of money circulation. Agents finance their expenditures not only by their own savings but also through bank loans. Through mathematical calculations and numerical simulation, we identify the determinants of money multiplier and those of velocity of money. In contrast to the traditional money creation model, the money multiplier is determined not only by the behavior of borrowing but also by the behavior of repayment as well. The velocity of money is found to be influenced by both money-related factors such as the expenditure habits of agents with respect to their income and wealth and debt-related factors such as borrowing and repayment behaviors of debtors and the reserve requirements faced by banks.

  9. The Use of Anthropogenic Tritium and Helium-3 to Study Subtropical Gyre Ventilation and Circulation

    NASA Astrophysics Data System (ADS)

    Jenkins, W. J.

    1988-05-01

    With tritium and helium-3 (3He) data from the Transient Tracers in the Ocean (TTO) expedition and from two other contemporaneous cruises, a synoptic picture of the ventilation and circulation of the subtropical North Atlantic is built. We will see clear evidence of gyre circulation in the tritium-3He age distributions on the shallower isopycnals, permitting estimates of the rates of circulation averaged over timescales from months to decades. The entry points of fluid into the main thermocline and the pathways of exchange with the upper ocean on seasonal to decade timescales appear clearly. It is the time-averaged transport processes on those timescales that are important to the uptake of carbon dioxide by the ocean. The overall relation between tritium and 3He within the subtropics exhibits a systematic hook-like pattern that is consistent with `strong' ventilation of the gyre thermocline; a fluid parcel entering the gyre thermocline making only about one circuit around the gyre before being ventilated. Finally, we present a time-series of 3He measurements made over a period of two years near Bermuda. The mixed layer is demonstrably supersaturated in this isotope throughout a large part of the year, requiring a gas-exchange flux of this isotope to the atmosphere. Model results are presented that permit the calculation of the in situ solubility isotope ratio anomaly for helium (as affected by bubble injection and gas exchange), and that can be used to estimate the upward flux of this isotope. Because only a small fraction of this flux can be produced in the mixed layer, this helium must be `mined' from the main thermocline. The computed flux is consistent with the long-term evolution of the inventories of tritium and 3He within the main thermocline. This flux has implications regarding the vertical transport of material within and from the permanent thermocline. A single observation of what may be one of the processes responsible for this upward flux is discussed

  10. African dust outbreaks over the western Mediterranean Basin: 11-year characterization of atmospheric circulation patterns and dust source areas

    NASA Astrophysics Data System (ADS)

    Salvador, P.; Alonso-Pérez, S.; Pey, J.; Artíñano, B.; de Bustos, J. J.; Alastuey, A.; Querol, X.

    2014-07-01

    The occurrence of African dust outbreaks over different areas of the western Mediterranean Basin were identified on an 11-year period (2001-2011). The main atmospheric circulation patterns causing the transport of African air masses were characterized by means of an objective classification methodology of atmospheric variable fields. Next, the potential source areas of mineral dust, associated to each circulation pattern were identified by trajectory statistical methods. Finally, an impact index was calculated to estimate the incidence of the African dust outbreaks produced during each circulation pattern, in the areas of study. Four circulation types were obtained (I-IV) and three main potential source areas of African dust were identified (Western Sahara and Morocco; Algeria; northeastern Algeria and Tunisia). The circulation pattern I (24% of the total number of episodic days) produced the transport of dust mainly in summer from Western Sahara, southern Morocco and Tunisia. The circulation pattern IV (33%) brings dust mainly from areas of northern and southern Algeria in summer and autumn, respectively. The circulation pattern II (31%) favored the transport of dust predominantly from northern Algeria, both in spring and summer. Finally, the circulation type III was the less frequently observed (12%). It occurred mainly in spring and with less intensity in winter, carrying dust from Western Sahara and southern Morocco. Our findings point out that the most intense episodes over the western Mediterranean Basin were produced in the summer period by the circulation type I (over the western side of the Iberian Peninsula) and the circulation type IV (over the central and eastern sides of the Iberian Peninsula and the Balearic Islands).

  11. Hemodynamic performance of the Fontan circulation compared with a normal biventricular circulation: a computational model study.

    PubMed

    Liang, Fuyou; Senzaki, Hideaki; Kurishima, Clara; Sughimoto, Koichi; Inuzuka, Ryo; Liu, Hao

    2014-10-01

    The physiological limitations of the Fontan circulation have been extensively addressed in the literature. Many studies emphasized the importance of pulmonary vascular resistance in determining cardiac output (CO) but gave little attention to other cardiovascular properties that may play considerable roles as well. The present study was aimed to systemically investigate the effects of various cardiovascular properties on clinically relevant hemodynamic variables (e.g., CO and central venous pressure). To this aim, a computational modeling method was employed. The constructed models provided a useful tool for quantifying the hemodynamic effects of any cardiovascular property of interest by varying the corresponding model parameters in model-based simulations. Herein, the Fontan circulation was studied compared with a normal biventricular circulation so as to highlight the unique characteristics of the Fontan circulation. Based on a series of numerical experiments, it was found that 1) pulmonary vascular resistance, ventricular diastolic function, and systemic vascular compliance play a major role, while heart rate, ventricular contractility, and systemic vascular resistance play a secondary role in the regulation of CO in the Fontan circulation; 2) CO is nonlinearly related to any single cardiovascular property, with their relationship being simultaneously influenced by other cardiovascular properties; and 3) the stability of central venous pressure is significantly reduced in the Fontan circulation. The findings suggest that the hemodynamic performance of the Fontan circulation is codetermined by various cardiovascular properties and hence a full understanding of patient-specific cardiovascular conditions is necessary to optimize the treatment of Fontan patients.

  12. Regional climates in the GISS global circulation model - Synoptic-scale circulation

    NASA Technical Reports Server (NTRS)

    Hewitson, B.; Crane, R. G.

    1992-01-01

    A major weakness of current general circulation models (GCMs) is their perceived inability to predict reliably the regional consequences of a global-scale change, and it is these regional-scale predictions that are necessary for studies of human-environmental response. For large areas of the extratropics, the local climate is controlled by the synoptic-scale atmospheric circulation, and it is the purpose of this paper to evaluate the synoptic-scale circulation of the Goddard Institute for Space Studies (GISS) GCM. A methodology for validating the daily synoptic circulation using Principal Component Analysis is described, and the methodology is then applied to the GCM simulation of sea level pressure over the continental United States (excluding Alaska). The analysis demonstrates that the GISS 4 x 5 deg GCM Model II effectively simulates the synoptic-scale atmospheric circulation over the United States. The modes of variance describing the atmospheric circulation of the model are comparable to those found in the observed data, and these modes explain similar amounts of variance in their respective datasets. The temporal behavior of these circulation modes in the synoptic time frame are also comparable.

  13. ON-LINE CALCULATOR: FORWARD CALCULATION JOHNSON ETTINGER MODEL

    EPA Science Inventory

    On-Site was developed to provide modelers and model reviewers with prepackaged tools ("calculators") for performing site assessment calculations. The philosophy behind OnSite is that the convenience of the prepackaged calculators helps provide consistency for simple calculations,...

  14. Synoptic-scale circulation patterns during summer derived from tree rings in mid-latitude Asia

    NASA Astrophysics Data System (ADS)

    Seim, Andrea; Schultz, Johannes A.; Leland, Caroline; Davi, Nicole; Byambasuren, Oyunsanaa; Liang, Eryuan; Wang, Xiaochun; Beck, Christoph; Linderholm, Hans W.; Pederson, Neil

    2016-11-01

    Understanding past and recent climate and atmospheric circulation variability is vital for regions that are affected by climate extremes. In mid-latitude Asia, however, the synoptic climatology is complex and not yet fully understood. The aim of this study was to investigate dominant synoptic-scale circulation patterns during the summer season using a multi-species tree-ring width (TRW) network comprising 78 sites from mid-latitude Asia. For each TRW chronology, we calculated an atmospheric circulation tree-ring index (ACTI), based on 1000 hPa geopotential height data, to directly link tree growth to 13 summertime weather types and their associated local climate conditions for the period 1871-1993. Using the ACTI, three groups of similarly responding tree-ring sites can be associated with distinct large-scale atmospheric circulation patterns: 1. growth of drought sensitive trees is positively affected by a cyclone over northern Russia; 2. temperature sensitive trees show positive associations to a cyclone over northwestern Russia and an anticyclone over Mongolia; 3. trees at two high elevation sites show positive relations to a zonal cyclone extending from mid-latitude Eurasia to the West Pacific. The identified synoptic-scale circulation patterns showed spatiotemporal variability in their intensity and position, causing temporally varying climate conditions in mid-latitude Asia. Our results highlight that for regions with less pronounced atmospheric action centers during summer such as the occurrence of large-scale cyclones and anticyclones, synoptic-scale circulation patterns can be extracted and linked to the Northern Hemisphere circulation system. Thus, we provide a new and solid envelope for climate studies covering the past to the future.

  15. Wall jet analysis for circulation control aerodynamics. Part 2: Zonal modeling concepts for wall jet/potential flow coupling

    NASA Technical Reports Server (NTRS)

    Dvorak, Frank A.; Dash, Sanford M.

    1987-01-01

    Work currently in progress to update an existing transonic circulation control airfoil analysis method is described. Existing methods suffer from two dificiencies: the inability to predict the shock structure of the underexpanded supersonic jets; and the insensitivity of the calculation to small changes in the Coanda surface geometry. A method developed for the analysis of jet exhaust plumes in supersonic flow is being modified for the case of the underexpanded wall jet. In the subsonic case, the same wall jet model was modified to include the calculation of the normal pressure gradient. This model is currently being coupled with the transonic circulation control airfoil analysis.

  16. Alemtuzumab treatment alters circulating innate immune cells in multiple sclerosis

    PubMed Central

    Ahmetspahic, Diana; Ruck, Tobias; Schulte-Mecklenbeck, Andreas; Schwarte, Kathrin; Jörgens, Silke; Scheu, Stefanie; Windhagen, Susanne; Graefe, Bettina; Melzer, Nico; Klotz, Luisa; Arolt, Volker; Wiendl, Heinz; Meuth, Sven G.

    2016-01-01

    Objective: To characterize changes in myeloid and lymphoid innate immune cells in patients with relapsing-remitting multiple sclerosis (MS) during a 6-month follow-up after alemtuzumab treatment. Methods: Circulating innate immune cells including myeloid cells and innate lymphoid cells (ILCs) were analyzed before and 6 and 12 months after onset of alemtuzumab treatment. Furthermore, a potential effect on granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)–23 production by myeloid cells and natural killer (NK) cell cytolytic activity was determined. Results: In comparison to CD4+ T lymphocytes, myeloid and lymphoid innate cell subsets of patients with MS expressed significantly lower amounts of CD52 on their cell surface. Six months after CD52 depletion, numbers of circulating plasmacytoid dendritic cells (DCs) and conventional DCs were reduced compared to baseline. GM-CSF and IL-23 production in DCs remained unchanged. Within the ILC compartment, the subset of CD56bright NK cells specifically expanded under alemtuzumab treatment, but their cytolytic activity did not change. Conclusions: Our findings demonstrate that 6 months after alemtuzumab treatment, specific DC subsets are reduced, while CD56bright NK cells expanded in patients with MS. Thus, alemtuzumab specifically restricts the DC compartment and expands the CD56bright NK cell subset with potential immunoregulatory properties in MS. We suggest that remodeling of the innate immune compartment may promote long-term efficacy of alemtuzumab and preserve immunocompetence in patients with MS. PMID:27766281

  17. Circulant Matrices and Time-Series Analysis

    ERIC Educational Resources Information Center

    Pollock, D. S. G.

    2002-01-01

    This paper sets forth some salient results in the algebra of circulant matrices which can be used in time-series analysis. It provides easy derivations of some results that are central to the analysis of statistical periodograms and empirical spectral density functions. A statistical test for the stationarity or homogeneity of empirical processes…

  18. Pneumatic system structure for circulation control aircraft

    NASA Technical Reports Server (NTRS)

    Krauss, Timothy A. (Inventor); Roman, Stephan (Inventor); Beurer, Robert J. (Inventor)

    1986-01-01

    A plenum for a circulation control rotor aircraft which surrounds the rotor drive shaft (18) and is so constructed that the top (32), outer (38) and bottom (36) walls through compressed air is admitted are fixed to aircraft structure and the inner wall (34) through which air passes to rotor blades (14) rotates with the drive shaft and rotor blades.

  19. Improving Circulation Services through Staff Involvement

    ERIC Educational Resources Information Center

    Kisby, Cynthia M.; Kilman, Marcus D.

    2007-01-01

    The Circulation Services Department at the University of Central Florida Libraries reports on leadership and training initiatives that resulted in a number of service-enhancing projects implemented by a highly motivated and involved staff. Key elements in reinvigorating the department included a change in leadership philosophy, increased…

  20. Oceanic Circulation. A Programmed Unit of Instruction.

    ERIC Educational Resources Information Center

    Marine Maritime Academy, Castine.

    This booklet contains a programmed lesson on oceanic circulation. It is designed to allow students to progress through the subject at their own speed. Since it is written in linear format, it is suggested that students proceed through the program from "frame" to succeeding "frame." Instructions for students on how to use the booklet are included.…

  1. A Circulation Model for Busy Public Libraries.

    ERIC Educational Resources Information Center

    Bagust, A.

    1983-01-01

    Develops stochastic model of library borrowing using Negative Binomial distribution applied to circulation data obtained from Huddersfield Public Library. Evidence concerning process of popularity decay is presented and method is given by which relegation tests can be constructed to maintain optimum turnover. Eight references and statistical…

  2. Detecting holocene changes in thermohaline circulation.

    PubMed

    Keigwin, L D; Boyle, E A

    2000-02-15

    Throughout the last glacial cycle, reorganizations of deep ocean water masses were coincident with rapid millennial-scale changes in climate. Climate changes have been less severe during the present interglacial, but evidence for concurrent deep ocean circulation change is ambiguous.

  3. A paleoceanographic circulation and chemistry model

    SciTech Connect

    Southam, J.R. )

    1990-01-09

    We have developed a 3-D circulation and tracer field model for paleoceanographic applications. The development of the model was motivated by the desire to explore Cretaceous Oceanic Anoxic Events and ocean chemistry during glacial and interglacial modes of circulation. The bulk of paleoceanographic data is the consequences of biological processes operating in ancient oceans. This type of data represents the response to environmental conditions and can be used to reconstruct water mass properties. To infer both wind driven and thermohaline components of circulation in ancient oceans requires a model which relates circulation and water mass properties. With this motivation in mind we have formulated a model which satisfies the following criteria: (1) geostrophically balanced interior, (2) multiple sites for deep water production, (3) deep water production described by entraining plumes, (4) high vertical resolution in both velocity and property fields, (5) meridional varibility in wind stress and evaporation-precipitation rate, (6) applicable to basin scale where exchange with adjacent oceans described by flux conditions, and (7) the chemistry is coupled through the flux of particulate carbon sinking through the interior.

  4. Providing Circulation Services in a Temporary Location

    ERIC Educational Resources Information Center

    Tolppanen, Bradley P.; Slough, Marlene

    2003-01-01

    This article presents the experience of Circulation Services at Booth Library, Eastern Illinois University, during a 31-month relocation to temporary facilities while the building was undergoing renovation. The move to temporary locations presented new challenges and required unique solutions. Issues such as the rationale for the move to the…

  5. A Classroom Demonstration of Thermohaline Circulation.

    ERIC Educational Resources Information Center

    Dudley, Walter C.

    1984-01-01

    Density-driven deep circulation is important in influencing geologic processes ranging from the dissolution of biogenic siliceous and calcareous sediments to the formation of erosional unconformities. A technique for dynamically demonstrating this process using an aquarium to enhance student understanding is described. (BC)

  6. A new look at cerebrospinal fluid circulation

    PubMed Central

    2014-01-01

    According to the traditional understanding of cerebrospinal fluid (CSF) physiology, the majority of CSF is produced by the choroid plexus, circulates through the ventricles, the cisterns, and the subarachnoid space to be absorbed into the blood by the arachnoid villi. This review surveys key developments leading to the traditional concept. Challenging this concept are novel insights utilizing molecular and cellular biology as well as neuroimaging, which indicate that CSF physiology may be much more complex than previously believed. The CSF circulation comprises not only a directed flow of CSF, but in addition a pulsatile to and fro movement throughout the entire brain with local fluid exchange between blood, interstitial fluid, and CSF. Astrocytes, aquaporins, and other membrane transporters are key elements in brain water and CSF homeostasis. A continuous bidirectional fluid exchange at the blood brain barrier produces flow rates, which exceed the choroidal CSF production rate by far. The CSF circulation around blood vessels penetrating from the subarachnoid space into the Virchow Robin spaces provides both a drainage pathway for the clearance of waste molecules from the brain and a site for the interaction of the systemic immune system with that of the brain. Important physiological functions, for example the regeneration of the brain during sleep, may depend on CSF circulation. PMID:24817998

  7. THE ESC COMPUTERIZED CIRCULATION SYSTEM MODEL II.

    ERIC Educational Resources Information Center

    SHAWVER, W.; STRAIN, P.M.

    A NEW CIRCULATION SYSTEM NOW IN USE AT THE ELECTRONICS SYSTEMS CENTER (ESC) LIBRARY, PART OF INTERNATIONAL BUSINESS MACHINES CORPORATION, IS BASED UPON A PREVIOUS SYSTEM WHICH USED TABULATING CARDS, UNIT RECORD MACHINES, AND A SMALL COMPUTER. THE NEW SYSTEM IS A TRANSACTION CARD SYSTEM, IN WHICH ONE BASIC TYPE OF CARD FORMAT IS USED FOR CHARGING,…

  8. Destabilization of the thermohaline circulation by atmospheric transports: An analytic solution

    SciTech Connect

    Krasovskiy, Y.P.; Stone, P.H.

    1998-07-01

    The four-box coupled atmosphere-ocean model of Marotzke is solved analytically, by introducing the approximation that the effect of oceanic heat advection on ocean temperatures is small (but not negligible) compared to the effect of surface heat fluxes. The solutions are written in a form that displays how the stability of the thermohaline circulation depends on the relationship between atmospheric meridional transports of heat and moisture and the meridional temperature gradient. In the model, these relationships are assumed to be power laws with different exponents allowed for the dependence of the transports of heat and moisture on the gradient. The approximate analytic solutions are in good agreement with Marotzke`s exact numerical solutions, but show more generally how the destabilization of the thermohaline circulation depends on the sensitivity of the atmospheric transports to the meridional temperature gradient. The solutions are also used to calculate how the stability of the thermohaline circulation is changed if model errors are corrected by using conventional flux adjustments. Errors like those common in GCMs destabilize the model`s thermohaline circulation, even if conventional flux adjustments are used. However, the resulting errors in the magnitude of the critical perturbations necessary to destabilize the thermohaline circulation can be corrected by modifying transport efficiencies instead.

  9. Bicompartmental analysis of cerebrospinal fluid circulation. Theory and clinical applications.

    PubMed

    Cabanes, J; Marti, J; Orozco, M; Beltran, A

    1983-08-01

    A new model for cerebrospinal fluid (CSF) circulation is proposed. Specific activity/time curves for CSF kinetics determined after intraventricular injection of a radiotracer were produced by fitting a biexponential function to data points and developing a two-compartmental model. Calculation of kinetic parameters of the model provides quantitative data about CSF dynamics. The study of each compartment separately and of the intercompartmental relationship is possible with this model. Sequential scan images and graphic plots of the variations of radioactivity in both compartments, derived from this model, add supplementary information in the evaluation of patients. Ventriculography was performed in 80 patients, who fell into four groups: those with normal CSF circulation, hydrocephalus, infantile hydrocephalus, and functioning ventricular shunts. Normal and hydrocephalic patients showed significant differences between the two groups in the means of some numerical parameters calculated from the new model. An increase of intraventricular radioactivity at 24 hours (p less than 10(-4)) and of the volume of Compartment 1 (p less than 0.01) with decreased volume of Compartment 2 (p less than 10(-4)) and total flow outside the system (p less than 10(-3)) were found in patients with hydrocephalus. The limiting values for normal patients were also estimated. Communicating and obstructive hydrocephalus could be differentiated by this method; however, no differences in mean values were found relating to the etiology or clinical course of the hydrocephalus. Normal-pressure hydrocephalus and cerebral atrophy produced significantly different mean values for the volume of Compartment 2 (p less than 0.01), flow out of the system (p less than 0.01), and intercompartmental flow (p less than 0.01).

  10. Effects of Microtopography on Overmarsh Circulation

    NASA Astrophysics Data System (ADS)

    Sullivan, J. C.; Torres, R.; Garrett, A.

    2013-12-01

    Authors: J.C. Sullivan, R. Torres, A.J. Garrett In this study we systematically degrade a high-resolution, high precision salt marsh DEM and characterize the effects of DEM smoothing on overmarsh circulation. The question driving this effort is: How much topographic detail is needed to accurately simulate salt marsh circulation? The hydrodynamic model Delft3D was applied to data from a previous dye-tracer study in a 2 km2 semi-enclosed salt marsh basin at Skidaway Institute of Oceanography near Savannah, Georgia, USA. Overmarsh circulation was simulated for each smoothed DEM over a 5 day period corresponding to spring tide conditions. Results show that flood and ebb pathways differ significantly, but this effect is less apparent as the DEM is smoothed. Also, the flushing time (Tf) decreases with smoothing leading to greater dilution of a dye tracer with each tidal cycle. Observations at the macro, meso and micro scale show that flood and ebb flows become stronger through a consistent set of flow paths, including intertidal creeks, and differences in overmarsh circulation are more apparent in low marsh and channel head areas. This work shows that accurate representation of overmarsh circulation requires that the DEM resolve creek and low lying marsh structures at a spatial scale of 2-4m, but not necessarily the smallest tidal creeks (< 1m in width and depth). The next phase of this work will be to incorporate spatial variations in vegetation cover using RULLI (Remote Ultra Low-Light Imaging) remote sensing technology developed by the Department of Energy.

  11. Applications of a Venus thermospheric circulation model

    NASA Technical Reports Server (NTRS)

    Bougher, S. W.; Dickinson, R. E.; Ridley, E. C.; Roble, R. G.

    1986-01-01

    A variety of Pioneer Venus observations suggest a global scale, day-to-night Venus thermospheric circulation. Model studies of the dynamics and energetics of the Venus thermosphere are presented in order to address new driving, mixing and cooling mechanisms for an improved model simulation. The adopted approach was to reexamine the circulation by first using a previous two dimensional code to quantify those physical processes which can be inferred from the Pioneer Venus observations. Specifically, the model was used to perform sensitivity studies to determine the degree to which eddy cooling, eddy or wave drag, eddy diffusion and 15 micrometer radiational cooling are necessary to bring the model temperature and composition fields into agreement with observations. Three EUV heating cases were isolated for study. Global temperature and composition fields in good agreement with Pioneer data were obtained. Large scale horizontal winds 220 m/s were found to be consistent with the observed cold nightside temperatures and dayside bulges of O, CO and CO2. Observed dayside temperatures were obtained by using a 7 to 19% EUV heating efficiency profile. The enhanced 15 micrometer cooling needed for thermal balance is obtained using the best rate coefficient available for atomic O collisional excitation of CO2(0,1,0). Eddy conduction was not found to be a viable cooling mechanism due to the weakened global circulation. The strong 15 micrometer damping and low EUV efficiency imply a very weak dependence of the general circulation to solar cycle variability. The NCAR terrestrial thermospheric general circulation model was adapted for Venus inputs using the above two dimensional model parameters, to give a three dimensional benchmark for future Venus modelling work.

  12. Circulation factors affecting precipitation over Bulgaria

    NASA Astrophysics Data System (ADS)

    Nojarov, Peter

    2017-01-01

    The objective of this paper is to determine the influence of circulation factors on precipitation in Bulgaria. The study succeeds investigation on the influence of circulation factors on air temperatures in Bulgaria, as the focus here is directed toward precipitation amounts. Circulation factors are represented through two circulation indices, showing west-east or south-north transport of air masses over Bulgaria and four teleconnection indices (patterns)—North Atlantic Oscillation, East Atlantic, East Atlantic/Western Russia, and Scandinavian. Omega values at 700-hPa level show vertical motions in the atmosphere. Annual precipitation trends are mixed and not statistically significant. A significant decrease of precipitation in Bulgaria is observed in November due to the strengthening of the eastward transport of air masses (strengthening of EA teleconnection pattern) and anticyclonal weather (increase of descending motions in the atmosphere). There is also a precipitation decrease in May and June due to the growing influence of the Azores High. An increase of precipitation happens in September. All this leads to a redistribution of annual precipitation course, but annual precipitation amounts remain the same. However, this redistribution has a negative impact on agriculture and winter ski tourism. Zonal circulation has a larger influence on precipitation in Bulgaria compared to meridional. Eastward transport throughout the year leads to lower than the normal precipitation, and vice versa. With regard to the four teleconnection patterns, winter precipitation in Bulgaria is determined mainly by EA/WR teleconnection pattern, spring and autumn by EA teleconnection pattern, and summer by SCAND teleconnection pattern.

  13. Energetic constraints on monsoonal Hadley circulations

    NASA Astrophysics Data System (ADS)

    Merlis, T. M.; Schneider, T.; Bordoni, S.; Eisenman, I.

    2011-12-01

    The strength of monsoons is believed to have varied in the past in response to changes in the seasonal shortwave radiation distribution associated with orbital precession and is expected to vary during the coming century due to increases in greenhouse gas concentrations. Here, we examine the constraint that the moist static energy budget imposes on the response to radiative perturbations of the cross-equatorial, or monsoonal, Hadley circulations. Changes in the strength of the mass transport can occur in response to radiative perturbations, which has been frequently discussed in the past. An additional factor in the energetic balance, however, is the atmosphere's energy stratification, which is commonly known as the gross moist stability in tropical meteorology. Therefore, changes in the atmosphere's gross moist stability can play a fundamental role in determining changes in the mass transport of mean circulations. Also, the influence of spatial variations in surface heat capacity on the top-of-the-atmosphere energy balance, rather than its widely discussed role in determining surface temperature, is important in determining how radiative perturbations are energetically balanced by monsoonal Hadley circulations. We examine the importance of energetic constraints on monsoonal Hadley circulations in idealized general circulation model simulations that have either an aquaplanet slab-ocean boundary condition or a zonally symmetric subtropical continent. The radiative balance in the simulations is perturbed first by insolation variations associated with orbital precession and then by increased carbon dioxide concentration. The simulation results demonstrate that summertime changes in gross moist stability are important for understanding past and future monsoon variations.

  14. Calculate waveguide aperture susceptance

    NASA Astrophysics Data System (ADS)

    Kwon, J.-K.; Ishii, T. K.

    1982-12-01

    A method is developed for calculating aperture susceptance which makes use of the distribution of an aperture's local fields. This method can be applied to the computation of the aperture susceptance of irises, as well as the calculation of the susceptances of waveguide filters, aperture antennas, waveguide cavity coupling, waveguide junctions, and heterogeneous boundaries such as inputs to ferrite or dielectric loaded waveguides. This method assumes a local field determined by transverse components of the incident wave in the local surface of the cross section in the discontinuity plane which lies at the aperture. The aperture susceptance is calculated by the use of the local fields, the law of energy conservation, and the principles of continuity of the fields. This method requires that the thickness of the aperture structure be zero, but this does not limit the practical usefulness of this local-field method.

  15. Evaluating the deep-ocean circulation of a global ocean model using carbon isotopic ratios

    NASA Astrophysics Data System (ADS)

    Paul, André; Dutkiewicz, Stephanie; Gebbie, Jake; Losch, Martin; Marchal, Olivier

    2016-04-01

    We study the sensitivity of a global three-dimensional biotic ocean carbon-cycle model to the parameterizations of gas exchange and biological productivity as well as to deep-ocean circulation strength, and we employ the carbon isotopic ratios δ13C and Δ14C of dissolved inorganic carbon for a systematic evaluation against observations. Radiocarbon (Δ14C) in particular offers the means to assess the model skill on a time scale of 100 to 1000 years relevant to the deep-ocean circulation. The carbon isotope ratios are included as tracers in the MIT general circulation model (MITgcm). The implementation involves the fractionation processes during photosynthesis and air-sea gas exchange. We present the results of sixteen simulations combining two different parameterizations of the piston velocity, two different parameterizations of biological productivity (including the effect of iron fertilization) and four different overturning rates. These simulations were first spun up to equilibrium (more than 10,000 years of model simulation) and then continued from AD 1765 to AD 2002. For the model evaluation, we followed the OCMIP-2 (Ocean Carbon-Cycle Model Intercomparision Project phase two) protocol, comparing the results to GEOSECS (Geochemical Ocean Sections Survey) and WOCE (World Ocean Circulation Experiment) δ13C and natural Δ14C data in the world ocean. The range of deep natural Δ14C (below 1000 m) for our single model (MITgcm) was smaller than for the group of different OCMIP-2 models. Furthermore, differences between different model parameterizations were smaller than for different overturning rates. We conclude that carbon isotope ratios are a useful tool to evaluate the deep-ocean circulation. Since they are also available from deep-sea sediment records, we postulate that the simulation of carbon isotope ratios in a global ocean model will aid in estimating the deep-ocean circulation and climate during present and past.

  16. Spin Resonance Strength Calculations

    NASA Astrophysics Data System (ADS)

    Courant, E. D.

    2009-08-01

    In calculating the strengths of depolarizing resonances it may be convenient to reformulate the equations of spin motion in a coordinate system based on the actual trajectory of the particle, as introduced by Kondratenko, rather than the conventional one based on a reference orbit. It is shown that resonance strengths calculated by the conventional and the revised formalisms are identical. Resonances induced by radiofrequency dipoles or solenoids are also treated; with rf dipoles it is essential to consider not only the direct effect of the dipole but also the contribution from oscillations induced by it.

  17. Geothermal Life Cycle Calculator

    DOE Data Explorer

    Sullivan, John

    2014-03-11

    This calculator is a handy tool for interested parties to estimate two key life cycle metrics, fossil energy consumption (Etot) and greenhouse gas emission (ghgtot) ratios, for geothermal electric power production. It is based solely on data developed by Argonne National Laboratory for DOE’s Geothermal Technologies office. The calculator permits the user to explore the impact of a range of key geothermal power production parameters, including plant capacity, lifetime, capacity factor, geothermal technology, well numbers and depths, field exploration, and others on the two metrics just mentioned. Estimates of variations in the results are also available to the user.

  18. Graphing Calculator Mini Course

    NASA Technical Reports Server (NTRS)

    Karnawat, Sunil R.

    1996-01-01

    The "Graphing Calculator Mini Course" project provided a mathematically-intensive technologically-based summer enrichment workshop for teachers of American Indian students on the Turtle Mountain Indian Reservation. Eleven such teachers participated in the six-day workshop in summer of 1996 and three Sunday workshops in the academic year. The project aimed to improve science and mathematics education on the reservation by showing teachers effective ways to use high-end graphing calculators as teaching and learning tools in science and mathematics courses at all levels. In particular, the workshop concentrated on applying TI-82's user-friendly features to understand the various mathematical and scientific concepts.

  19. [Oxygen-transporting function of the blood circulation system in sevoflurane anesthesia during myocardial revascularization under extracorporeal circulation].

    PubMed

    Skopets, A A; Lomivorotov, V V; Karakhalis, N B; Makarov, A A; Duman'ian, E S; Lomivorotova, L V

    2009-01-01

    The purpose of the study was to evaluate the efficiency of oxygen-transporting function of the circulatory system under sevoflurane anesthesia during myocardial revascularization operations under extracorporeal circulation. Twenty-five patients with coronary heart disease were examined. Mean blood pressure, heart rate, cardiac index, total peripheral vascular resistance index, pulmonary pressure, pulmonary wedge pressure, and central venous pressure were measured. Arterial and mixed venous blood oxygen levels, oxygen delivery and consumption index, arteriovenous oxygen difference, and glucose and lactate concentrations were calculated. The study has demonstrated that sevoflurane is an effective and safe anesthetic for myocardial revascularization operations in patients with coronary heart disease. The use of sevoflurane contributes to steady-state oxygen-transporting function of the circulatory system at all surgical stages.

  20. Diversity of Planetary Atmospheric Circulations and Climates in a Simplified General Circulation Model

    NASA Astrophysics Data System (ADS)

    Wang, Yixiong; Read, Peter

    2014-04-01

    The parametric dependence of terrestrial planetary atmospheric circulations and climates on characteristic parameters is studied. A simplified general circulation model-PUMA is employed to investigate the dynamic effects of planetary rotation rate and equator-to-pole temperature difference on the circulation and climate of terrestrial planetary atmospheres. Five different types of circulation regime are identified by mapping the experimental results in a 2-D parameter space defined by thermal Rossby number and frictional Taylor number. The effect of the transfer and redistribution of radiative energy is studied by building up a new two-band semi-gray radiative-convective scheme, which is capable of modelling greenhouse and anti-greenhouse effects while keeping the tunable parameters as few as possible. The results will provide insights into predicting the habitability of terrestrial exoplanets.

  1. Circulating miRNAs: roles in cancer diagnosis, prognosis and therapy.

    PubMed

    Cheng, Guofeng

    2015-01-01

    MicroRNAs (miRNAs) belong to a class of small non-coding RNAs that regulate numerous biological processes by targeting a broad set of messenger RNAs. Recently, miRNAs have been detected in remarkably stable forms in many types of body fluids. A comparison between cancer patients and healthy individuals has clearly shown that certain types of circulating miRNAs are associated with cancer initiation and progression. Research on miRNA-based biomarkers has witnessed phenomenal growth, owing to the non-invasive nature of miRNA-based screening assays and their sensitivity and specificity in detecting cancers. Consequently, a considerable effort has been devoted to identify suitable miRNAs for cancer diagnosis and also decode the information carried by circulating miRNAs. This review highlights the current studies that focus on the identification of circulating miRNA-based diagnostic and prognostic markers, for the most prevalent types of cancer. Additionally, the review also provides an insight into the putative functions of miRNAs, and attempts to delineate the mechanisms through which they are released into the bloodstream. Moreover, methodologies and strategies for identification of circulating miRNAs in cancers are summarized. Finally, potential strategies for circulating miRNA-based cancer therapies are proposed.

  2. Slowdown of the Walker circulation driven by tropical Indo-Pacific warming.

    PubMed

    Tokinaga, Hiroki; Xie, Shang-Ping; Deser, Clara; Kosaka, Yu; Okumura, Yuko M

    2012-11-15

    Global mean sea surface temperature (SST) has risen steadily over the past century, but the overall pattern contains extensive and often uncertain spatial variations, with potentially important effects on regional precipitation. Observations suggest a slowdown of the zonal atmospheric overturning circulation above the tropical Pacific Ocean (the Walker circulation) over the twentieth century. Although this change has been attributed to a muted hydrological cycle forced by global warming, the effect of SST warming patterns has not been explored and quantified. Here we perform experiments using an atmospheric model, and find that SST warming patterns are the main cause of the weakened Walker circulation over the past six decades (1950-2009). The SST trend reconstructed from bucket-sampled SST and night-time marine surface air temperature features a reduced zonal gradient in the tropical Indo-Pacific Ocean, a change consistent with subsurface temperature observations. Model experiments with this trend pattern robustly simulate the observed changes, including the Walker circulation slowdown and the eastward shift of atmospheric convection from the Indonesian maritime continent to the central tropical Pacific. Our results cannot establish whether the observed changes are due to natural variability or anthropogenic global warming, but they do show that the observed slowdown in the Walker circulation is presumably driven by oceanic rather than atmospheric processes.

  3. Wind effect on the Atlantic meridional overturning circulation via sea ice and vertical diffusion

    NASA Astrophysics Data System (ADS)

    Yang, Haijun; Wang, Kun; Dai, Haijin; Wang, Yuxing; Li, Qing

    2016-06-01

    Effects of wind and fresh water on the Atlantic meridional overturning circulation (AMOC) are investigated using a fully coupled climate model. The AMOC can change significantly when perturbed by either wind stress or freshwater flux in the North Atlantic. This study focuses on wind stress effect. Our model results show that the wind forcing is crucial in maintaining the AMOC. Reducing wind forcing over the ocean can cause immediately weakening of the vertical salinity diffusion and convection in the mid-high latitudes Atlantic, resulting in an enhancement of vertical salinity stratification that restrains the deep water formation there, triggering a slowdown of the thermohaline circulation. As the thermohaline circulation weakens, the sea ice expands southward and melts, providing the upper ocean with fresh water that weakens the thermohaline circulation further. The wind perturbation experiments suggest a positive feedback between sea-ice and thermohaline circulation strength, which can eventually result in a complete shutdown of the AMOC. This study also suggests that sea-ice variability may be also important to the natural AMOC variability on decadal and longer timescales.

  4. [Myelopathies in impairment of extravertebral venous blood circulation].

    PubMed

    Tsuladze, I I; Dreval', O N; Kornienko, V N

    2009-01-01

    Development of myelopathies of venous genesis is based on venous hypertension inside vertebral canal which was initially described by J. Aboulker. According to anatomical and functional features of epidural venous system, two factors contribute in development of venous congestion: decreased outflow and increased inflow. Clinical manifestation is presented by spastic movement disorders. Morphological study performed in 18 cadavers allowed to discover so called 'narrow areas' which cause impaired circulation through large feeders of caval veins, which can be discovered by selective phlebography. Main phlebographic features include stenosis, compression, atresia, thrombosis and retrograde flow towards epidural venous plexus. We examined 58 patients with spastic para- and tetraparesis of unknown nature. Phlebographic signs of venous dyscirculation were revealed in 34 cases. 28 surgical operations were performed: 24 on feeders of vena cava superior and 4 on feeders of vena cava inferior. In 18 cases we obtained satisfactory results. This investigation should be continued.

  5. (CO sub 2 uptake in an Ocean Circulation Model)

    SciTech Connect

    Siegenthaler, U.C.

    1990-11-06

    The traveler collaborated with Drs. J. L. Sarmiento and J. C. Orr of the Program in Atmospheric Sciences at Princeton University to finish the article A Perturbation Simulation of CO{sub 2} Uptake in an Ocean Circulation Model,'' which has been submitted to the Journal of Geophysical Research for publication. With F. Joos, a graduate student from the University of Bern, the traveler started writing a journal article describing a box model of the global carbon cycle that is an extension of the one-dimensional box-diffusion model. The traveler further collaborated with F. Joos and Dr. J. L. Sarmiento on modeling the potential enhancement of oceanic CO{sub 2} uptake by fertilizing the southern ocean with iron. A letter describing the results is currently being written for the journal Nature.

  6. Influence of seasonal circulation on flushing of the Irish Sea.

    PubMed

    Dabrowski, T; Hartnett, M; Olbert, A I

    2010-05-01

    We applied a three-dimensional general ocean and coastal circulation model to the Irish Sea in order to determine water renewal time scales in the region. The model was forced with meteorological data for 1995, a year with relatively warm summer and when extensive hydrographic surveys were conducted in the Irish Sea. We investigated intra-annual variability in the rates of net flow through the Irish Sea and carried out several flushing simulations based on conservative tracer transport. The results indicate that the net northward flow of 2.50 km(3)/d is seasonally highly variable and under certain conditions is reversed to southward. The variability in obtained residence times is high; baroclinic effects are significant. Obtained results point at the importance of spatial and temporal consideration for transport of pollutants in the shelf seas. Implications for management are numerous and involve activities such as transport, fishing, use of resources, nature conservation, monitoring, tourism and recreation.

  7. [The discovery of blood circulation: revolution or revision?].

    PubMed

    Crignon, Claire

    2011-01-01

    The discovery of the principle of blood circulation by William Harvey is generally considered as one of the major events of the "scientific revolution" of the 17th century. This paper reconsiders the question by taking in account the way Harvey's discovery was discussed by some contemporary philosophers and physicians, in particular Fontenelle, who insisted on the necessity of redefining methods and principles of medical knowledge, basing themselves on the revival of anatomy and physiology, and of its consequences on the way it permits to think about the human nature. This return allows us to consider the opportunity of substituting the kuhnian scheme of "structure of scientific revolutions" for the bachelardian concept of "refonte".

  8. Hydrothermal circulation in fast spread ocean crust - where and how much? Insight from ODP Hole 1256D

    NASA Astrophysics Data System (ADS)

    Harris, M.; Coggon, R. M.; Smith-Duque, C. E.; Teagle, D. A. H.

    2014-12-01

    Understanding and quantifying hydrothermal circulation is critical to testing models of the accretion of lower ocean crust and quantifying global geochemical cycles. However, our understanding is principally limited by a lack of direct observations from intact ocean crust. Key questions remain about the magnitude of hydrothermal fluid fluxes, the nature and distribution of fluid pathways and their global variability. ODP Hole 1256D in the eastern equatorial Pacific samples a complete section of 15 Myr old upper ocean crust down to the dike/gabbro transition zone. A high spatial resolution Sr isotope profile is integrated with wireline studies, volcanostratigraphy, petrography and mineral geochemistry to document fluid pathways and develop a model for the evolving hydrothermal system during volcanic construction of the crust. Major off-axis fluid conduits in the volcanic sequence are restricted to the flow margins of two anomalously thick (>25 m) massive flows, indicating that massive flows act as a permeability barrier for fluid flow. Dike margins are pathways for both recharge and discharge hydrothermal fluids. Sub-horizontal channeling of high temperature fluids at the dike/gabbro boundary is a common attribute of most cartoons of mid ocean ridge hydrothermal systems. Hole 1256D provides the first in situ observations of the dike/gabbro transition zone and records lateral fluid transport along intrusive boundaries. The time-integrated fluid flux in the sheeted dikes of Hole 1256D calculated using Sr isotope mass balance is ~1.8 x 106 kg/m2. This is similar to fluid fluxes from other studies (Hole 504B, Pito Deep, Hess Deep) despite large variations in the thickness and Sr isotope profiles of the sheeted dike complexes, suggesting that hydrothermal fluid fluxes are remarkably uniform and independent of the local structure of the crust. This fluid flux is not large enough to completely remove the heat flux from crystallizing and cooling the lower crust and requires

  9. Airborne antenna pattern calculations

    NASA Technical Reports Server (NTRS)

    Bagherian, A. B.; Mielke, R. R.

    1983-01-01

    Use of calculation program START and modeling program P 3D to produce radiation patterns of antennas mounted on a space station is discussed. Basic components of two space stations in the early design stage are simulated and radiation patterns for antennas mounted on the modules are presented.

  10. Solar Guide and Calculator.

    ERIC Educational Resources Information Center

    Mazria, Edward; Winitsky, David

    This guide provides users with a basic understanding of where and how the sun works in relation to a building and site and provides a simplified method of calculating sun angles and the available heat energy from the sun on vertical and horizontal surfaces. (Author/IRT)

  11. A Computer Calculated Index.

    ERIC Educational Resources Information Center

    Brown, Francis J.

    The Gunning Fog Index of readability indicates both the average length of words and the difficult words (three or more syllables) in written material. This document describes a business communication course at Wayne State University in which students calculate the Gunning Fog Index of two of their writing assignments with the aid of the…

  12. Airborne antenna pattern calculations

    NASA Technical Reports Server (NTRS)

    Knerr, T. J.; Owens, T. M.; Mielke, R. R.

    1981-01-01

    Calculated principal-and off-principal plane patterns are presented for the following aircraft: de Havilland DHC-7, Rockwell Sabreliner 75A, Piper PA-31T Cheyenne, Lockheed Jet Star II, Piper PA-31-350 Navajo Chieftain, Beechcraft Duke B60, Rockwell Commander 700, Cessna Citation 3, Piper PA-31P Pressurized Navajo, Lear Jet, and Twin Otter DHC-6.

  13. Calculation of enviromental indices

    SciTech Connect

    1995-10-01

    This portion of the Energy Vision 2020 draft report discusses the development of environmental indices. These indices were developed to be a quantitative measure of characterizing how TVA power system operations and alternative energy strategies might affect the environment. All indices were calculated relative to the reference strategy, and for the environmental review, the reference strategy was `no action`.

  14. Tunnel closure calculations

    SciTech Connect

    Moran, B.; Attia, A.

    1995-07-01

    When a deeply penetrating munition explodes above the roof of a tunnel, the amount of rubble that falls inside the tunnel is primarily a function of three parameters: first the cube-root scaled distance from the center of the explosive to the roof of the tunnel. Second the material properties of the rock around the tunnel, and in particular the shear strength of that rock, its RQD (Rock Quality Designator), and the extent and orientation of joints. And third the ratio of the tunnel diameter to the standoff distance (distance between the center of explosive and the tunnel roof). The authors have used CALE, a well-established 2-D hydrodynamic computer code, to calculate the amount of rubble that falls inside a tunnel as a function of standoff distance for two different tunnel diameters. In particular they calculated three of the tunnel collapse experiments conducted in an iron ore mine near Kirkeness, Norway in the summer of 1994. The failure model that they used in their calculations combines an equivalent plastic strain criterion with a maximum tensile strength criterion and can be calibrated for different rocks using cratering data as well as laboratory experiments. These calculations are intended to test and improve the understanding of both the Norway Experiments and the ACE (Array of conventional Explosive) phenomenology.

  15. Tidal circulation alteration for salt marsh mosquito control

    NASA Astrophysics Data System (ADS)

    Resh, Vincent H.; Balling, Steven S.

    1983-01-01

    Mosquito control ditches designed to increase tidal circulation are widely used as a physical control alternative to insecticidal applications The impact of such ditching on Pacific Coast marshlands was largely unknown before this five-year study of impact in two types of San Francisco Bay salt marshes, a Salicornia virginica (pickleweed) monoculure and a mixed vegetation marsh Results of our studies suggest that ditches cause less environmental disturbance than insecticidal applications The article describes the following environmental consequences of ditching for mosquito control: increased tidal flushing of soils occurs adjacent to ditches compared with that in the open marsh, thereby reducing ground water and soil surface salinities and water table height; primary productivity of S. virginica, as determined by both the harvest method and infrared photographic analysis, is higher directly adjacent to ditches than in the open marsh, distribution of selected arthropod populations is similar at ditches and natural channels, although arthropod community response differs seasonally; aquatic invertebrate biomass is similar within ditched and natural ponds, but diversity is lower in ditched habitats, ditching increases fish diversity and density by improving fish access from tidal channels; ditches provide additional salt marsh song sparrow habitat, although ditches are less preferred than natural channels or sloughs. Management criteria can be used to design ditches that provide effective mosquito control and reduced environmental impact

  16. Matematica Natural.

    ERIC Educational Resources Information Center

    Lozano, Patricia; Medearis, Linda

    Matematica Natural (Natural Mathematics) is a mathematics curriculum for young children based on the assumption that they learn mathematics through concrete, real life, relevant experiences and that educational differences rather than cultural differences influence math achievement. The curriculum uses hands-on materials and activities to teach…

  17. Natural Beauty

    ERIC Educational Resources Information Center

    Coy, Mary

    2006-01-01

    In this article, the author describes how her art class students were able to create, in just four class periods, clay relief plaques depicting nature. A lesson on texture speeds up the completion of such a project. Seeing that clay is a natural material with its own unique texture, it seemed fitting that the final product should depict a variety…

  18. Firsthand Nature

    ERIC Educational Resources Information Center

    Gostev, Moses; Weiss, Francesca Michaelides

    2007-01-01

    It's no secret that many school programs don't give children enough opportunity to explore the natural world--i.e., to "mess about" and to have firsthand experience with nature and animals. Not so at the Muscota New School in New York City! This innovative public elementary school actively promotes inquiry-based learning and encourages…

  19. Nature Detectives

    ERIC Educational Resources Information Center

    Harr, Natalie; Lee, Richard E.; Jr.

    2010-01-01

    Richard Louv's "Last Child in the Woods" (2008) added to a growing consensus to get children outside and experiencing nature. Using ideas from place-based education, the authors present a simple year-long project that brings science, nature, and other curriculum standards to life right in your school yard. With a focus on journaling, this project…

  20. Plutonium 239 Equivalency Calculations

    SciTech Connect

    Wen, J

    2011-05-31

    This document provides the basis for converting actual weapons grade plutonium mass to a plutonium equivalency (PuE) mass of Plutonium 239. The conversion can be accomplished by performing calculations utilizing either: (1) Isotopic conversions factors (CF{sub isotope}), or (2) 30-year-old weapons grade conversion factor (CF{sub 30 yr}) Both of these methods are provided in this document. Material mass and isotopic data are needed to calculate PuE using the isotopic conversion factors, which will provide the actual PuE value at the time of calculation. PuE is the summation of the isotopic masses times their associated isotopic conversion factors for plutonium 239. Isotopic conversion factors are calculated by a normalized equation, relative to Plutonium 239, of specific activity (SA) and cumulated dose inhalation affects based on 50-yr committed effective dose equivalent (CEDE). The isotopic conversion factors for converting weapons grade plutonium to PuE are provided in Table-1. The unit for specific activity (SA) is curies per gram (Ci/g) and the isotopic SA values come from reference [1]. The cumulated dose inhalation effect values in units of rem/Ci are based on 50-yr committed effective dose equivalent (CEDE). A person irradiated by gamma radiation outside the body will receive a dose only during the period of irradiation. However, following an intake by inhalation, some radionuclides persist in the body and irradiate the various tissues for many years. There are three groups CEDE data representing lengths of time of 0.5 (D), 50 (W) and 500 (Y) days, which are in reference [2]. The CEDE values in the (W) group demonstrates the highest dose equivalent value; therefore they are used for the calculation.

  1. Circulation patterns in active lava lakes

    NASA Astrophysics Data System (ADS)

    Redmond, T. C.; Lev, E.

    2014-12-01

    Active lava lakes provide a unique window into magmatic conduit processes. We investigated circulation patterns of 4 active lava lakes: Kilauea's Halemaumau crater, Mount Erebus, Erta Ale and Nyiragongo, and in an artificial "lava lake" constructed at the Syracuse University Lava Lab. We employed visual and thermal video recordings collected at these volcanoes and use computer vision techniques to extract time-dependent, two-dimensional surface velocity maps. The large amount of data available from Halemaumau enabled us to identify several characteristic circulation patterns. One such pattern is a rapid acceleration followed by rapid deceleration, often to a level lower than the pre-acceleration level, and then a slow recovery. Another pattern is periodic asymmetric peaks of gradual acceleration and rapid deceleration, or vice versa, previously explained by gas pistoning. Using spectral analysis, we find that the dominant period of circulation cycles at approximately 30 minutes, 3 times longer than the dominant period identified previously for Mount Erebus. Measuring a complete surface velocity field allowed us to map and follow locations of divergence and convergence, therefore upwelling and downwelling, thus connecting the surface flow with that at depth. At Nyiragongo, the location of main upwelling shifts gradually, yet is usually at the interior of the lake, for Erebus it is usually along the perimeter yet often there is catastrophic downwelling at the interior; For Halemaumau upwelling/downwelling position is almost always on the perimeter. In addition to velocity fields, we developed an automated tool for counting crustal plates at the surface of the lava lakes, and found a correlation, and a lag time, between changes if circulation vigor and the average size of crustal plates. Circulation in the artificial basaltic lava "lake" was limited by its size and degree of foaming, yet we measured surface velocities and identify patterns. Maximum surface velocity

  2. The circulation of eastern Canadian seas

    NASA Astrophysics Data System (ADS)

    Wu, Yongsheng; Tang, Charles; Hannah, Charles

    2012-11-01

    The eastern Canadian seas including Baffin Bay, the Labrador Sea and shelf, the N.E. Newfoundland Shelf, the Scotian Shelf and the Gulf of St. Lawrence form an integrated hydro-dynamical system. The circulation is investigated using current meter data and a high resolution three dimensional coupled ice-ocean circulation model, CECOM (Canadian East Coast Ocean Model) covering the entire area. The model is forced with realistic atmosphere fluxes and the results are compared to the current meter data collected in four selected periods between 1987 and 2008. Many features of the model current fields are similar to those from the previous regional circulation models for the shelves. New findings from CECOM include seasonal differences of the circulation around Davis Strait, the detailed structure of the Labrador Current re-circulation, two cross-shelf currents on the Scotian Shelf, and strong currents in Halibut Channel which connects the waters of the western Grand Banks and Scotian Shelf. The annual variation of the circulation is investigated. Both the model and data show the Labrador Current is strong in fall and weak in spring. The outflow from the Gulf of St. Lawrence through Cabot Strait and the currents on the inner Scotian Shelf are strong in winter and fall and weak in spring, and are in phase with the Labrador Current. The model currents are compared to observations using a qualitative method of visual comparison, and a quantitative method based on statistical analysis. The comparisons indicate that the main features of the current fields from the observations are successfully reproduced by the model. The quantitative analysis indicates that the model currents are in reasonable agreement with the observations. Specifically, a good agreement is found in the Labrador shelf, Newfoundland Shelf and Flemish Pass, a fair agreement is found in Davis Strait, the inner Scotian Shelf and Sable Bank. However, the agreement for Cabot Strait and the Scotian Shelf break is

  3. Controls on the physics and chemistry of seafloor hydrothermal circulation

    NASA Astrophysics Data System (ADS)

    Schultz, A.; Elderfield, H.

    Low temperature diffuse hydrothermal circulation is a natural consequence of the cooling of the oceanic lithosphere. Diffuse flow is expected to be ubiquitous, and will be present both within mid-ocean ridge crest axial zones of young age (0-1 Ma), and also on the older ridge crest flanks and limbs. If underlying thermal models are correct, hydrothermal circulation should persist for oceanic lithosphere of age 0-65 Ma, and is present over half the total area of the ocean basins. By using numerical models of hydrothermal circulation in cracked permeable media, we show qualitatively how diffuse flow is an intrinsic feature of high temperature axial (0-1 Ma) hydrothermal systems, and is not restricted to older (more than 1 Ma) lithosphere. This is in agreement with our field observations which suggest that in such high temperature vent fields the greatest part of the heat and volume flux is due to lower temperature diffuse flow, rather than high temperature black smoker venting. By combining direct measurements of the physical properties of diffusely flowing effluent within axial hydrothermal systems with concurrent sampling of the chemical properties of that effluent, and by considering also the chemistry of unmixed black smoker endmember fluids from the same hydrothermal systems, the processes of mineral deposition and dissolution can be studied directly. By referring to the present-day lithology of such areas, it is possible to examine the balance between concurrent mineral deposition and dissolution processes, and the retention rate of specific mineral assemblages integrated over the history of the hydrothermal system. Thus details of the episodicity of hydrothermal venting within the system may be revealed. An example of this method of combining a variety of direct measurements of diffuse and high temperature effluent properties is given from the TAG hydrothermal field, Mid-Atlantic Ridge. Long time series observations of the physical properties of diffuse and

  4. A probabilistic approach to attribute warming to changes in atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Brox Nilsen, Irene; Stagge, James Howard; Merete Tallaksen, Lena

    2016-04-01

    Europe has been warming over the past decades, especially in southern Europe in summer and northern Europe in winter. To understand the causes of regional warming, it is common to separate the temperature change signal into changes in atmospheric circulation (or dynamic causes) and other factors, so-called within-type changes (or thermodynamic causes). For example, increasing temperatures due to greenhouse gases may alter the position and strength of the polar jet stream, thus causing a change in the atmospheric circulation signal. On the other hand, warming may be entirely independent of circulation, occurring as a general increase in surface temperature. With the aim to detect regions and time of the year in Europe in which recent warming can either be explained by changes in atmospheric circulation or by within-type changes, we suggest a novel probabilistic approach to calculate the circulation-induced trend, the part of the temperature trend that is induced by changes in atmospheric circulation. Through the use of resampling, in combination with a Monte Carlo test, we assessed the likelihood that the observed temperature trend can be explained entirely by changes in atmospheric circulation frequency. The temperature data originate from the gridded 0.5° Watch Forcing Data Era-Interim (WFDEI), and cover the period 1981-2010. The SynopVis Grosswetterlagen catalogue of circulation types was used to detect circulation-induced trends in the same time period. We analysed trends on the monthly time scale to reveal short-term responses, such as those related to snow or greening. The most wide-spread observed warming was found in summer, with up to 60% of the European land area experiencing a significant warming trend during August, most notable in eastern and northern Europe. In spring and autumn, the percent area with significant temperature increases reduced to 10-30%. In December and January, only 5% of the land area experienced significant warming, most pronounced

  5. A continued fraction representation for Theodorsen's circulation function

    NASA Technical Reports Server (NTRS)

    Desmarais, R. N.

    1980-01-01

    Theodorsen's circulation function relates lift to downwash in unsteady two dimensional incompressible flow. A continued fraction representation for the circulation function is described. The continued fraction converges and has a particularly simple coefficient pattern.

  6. Calculation of effective dose.

    PubMed

    McCollough, C H; Schueler, B A

    2000-05-01

    The concept of "effective dose" was introduced in 1975 to provide a mechanism for assessing the radiation detriment from partial body irradiations in terms of data derived from whole body irradiations. The effective dose is the mean absorbed dose from a uniform whole-body irradiation that results in the same total radiation detriment as from the nonuniform, partial-body irradiation in question. The effective dose is calculated as the weighted average of the mean absorbed dose to the various body organs and tissues, where the weighting factor is the radiation detriment for a given organ (from a whole-body irradiation) as a fraction of the total radiation detriment. In this review, effective dose equivalent and effective dose, as established by the International Commission on Radiological Protection in 1977 and 1990, respectively, are defined and various methods of calculating these quantities are presented for radionuclides, radiography, fluoroscopy, computed tomography and mammography. In order to calculate either quantity, it is first necessary to estimate the radiation dose to individual organs. One common method of determining organ doses is through Monte Carlo simulations of photon interactions within a simplified mathematical model of the human body. Several groups have performed these calculations and published their results in the form of data tables of organ dose per unit activity or exposure. These data tables are specified according to particular examination parameters, such as radiopharmaceutical, x-ray projection, x-ray beam energy spectra or patient size. Sources of these organ dose conversion coefficients are presented and differences between them are examined. The estimates of effective dose equivalent or effective dose calculated using these data, although not intended to describe the dose to an individual, can be used as a relative measure of stochastic radiation detriment. The calculated values, in units of sievert (or rem), indicate the amount of

  7. DEVELOPMENT OF WATER CIRCULATION MODEL INCLUDING IRRIGATION

    NASA Astrophysics Data System (ADS)

    Kotsuki, Shunji; Tanaka, Kenji; Kojiri, Toshiharu; Hamaguchi, Toshio

    It is well known that since agricultural water withdrawal has much affect on water circulation system, accurate analysis of river discharge or water balance are difficult with less regard for it. In this study, water circulation model composed of land surface model and distributed runoff model is proposed at 10km 10km resolution. In this model, irrigation water, which is estimated with land surface model, is introduced to river discharge analysis. The model is applied to the Chao Phraya River in Thailand, and reproduced seasonal water balance. Additionally, the discharge on dry season simulated with the model is improved as a result of including irrigation. Since the model, which is basically developed from global data sets, simulated seasonal change of river discharge, it can be suggested that our model has university to other river basins.

  8. On-Chip Microwave Quantum Hall Circulator

    NASA Astrophysics Data System (ADS)

    Mahoney, A. C.; Colless, J. I.; Pauka, S. J.; Hornibrook, J. M.; Watson, J. D.; Gardner, G. C.; Manfra, M. J.; Doherty, A. C.; Reilly, D. J.

    2017-01-01

    Circulators are nonreciprocal circuit elements that are integral to technologies including radar systems, microwave communication transceivers, and the readout of quantum information devices. Their nonreciprocity arises from the interference of microwaves over the centimeter scale of the signal wavelength, in the presence of bulky magnetic media that breaks time-reversal symmetry. Here, we realize a completely passive on-chip microwave circulator with size 1 /1000 th the wavelength by exploiting the chiral, "slow-light" response of a two-dimensional electron gas in the quantum Hall regime. For an integrated GaAs device with 330 μ m diameter and about 1-GHz center frequency, a nonreciprocity of 25 dB is observed over a 50-MHz bandwidth. Furthermore, the nonreciprocity can be dynamically tuned by varying the voltage at the port, an aspect that may enable reconfigurable passive routing of microwave signals on chip.

  9. Modeling mesoscale circulation of the Black Sea

    NASA Astrophysics Data System (ADS)

    Korotenko, K. A.

    2015-11-01

    An eddy-resolving (1/30)° version of the DieCAST low-dissipative model, adapted to the Black Sea circulation, is presented. Under mean climatological forcing, the model realistically reproduces major dominant large-scale and mesoscale structures of seasonal sea circulation, including the Rim Current, coastal anticyclonic eddies, mushroom currents, etc. Due to its extremely low dissipation and high resolution, the model makes it possible to trace the development of the baroclinic instability along the Turkish and Caucasian coasts, reproduce mesoscale structures generated by this mechanism, and assess the scales of these structures. The model also realistically reproduces short-term effects of bora winds on the evolution of subsurface layer structures.

  10. Blood circulation under conditions of weightlessness

    NASA Technical Reports Server (NTRS)

    Kastyan, I. I.; Kopanev, V. I.

    1980-01-01

    Experimental materials and published data on the problem of blood circulation in man and animals under conditions of short and long term weightlessness are summarized. The data obtained allow the conclusion, that when humans spent 5 days in a weightless state their blood circulation was not essentially distributed. Some features of the functioning of the cardiovascular system are pointed out: delay of adaptation rate, increase in lability, etc. There is a discussion of the physiological mechanisms for the direct and indirect effect of weightlessness. The direct effect comprise the complex of reactions caused by the significant fall in hydrostatic pressure and the indirect embraces all the reactions arising in the organism resulting from disturbance of the systematic character of the analyzers that take part in the analysis of space realtions and the body's orientation in space.

  11. Circulating elastin peptides, role in vascular pathology.

    PubMed

    Robert, L; Labat-Robert, J

    2014-12-01

    The atherosclerotic process starts with the degradation of elastic fibers. Their presence was demonstrated in the circulation as well as several of their biological properties elucidated. We described years ago a procedure to obtain large elastin peptides by organo-alkaline hydrolysis, κ-elastin. This method enabled also the preparation of specific antibodies used to determine elastin peptides, as well as anti-elastin antibodies in body fluids and tissue extracts. Elastin peptides were determined in a large number of human blood samples. Studies were carried out to explore their pharmacological properties. Similar recent studies by other laboratories confirmed our findings and arose new interest in circulating elastin peptides for their biological activities. This recent trend justified the publication of a review of the biological and pathological activities of elastin peptides demonstrated during our previous studies, subject of this article.

  12. Congenital cardiovascular malformations and the fetal circulation.

    PubMed

    Rudolph, A M

    2010-03-01

    After birth, gas exchange is achieved in the lung, whereas prenatally it occurs in the placenta. This is associated with differences in blood flow patterns in the fetus as compared with the postnatal circulation. Congenital cardiovascular malformations are associated with haemodynamic changes in the fetus, which differ from those occurring postnatally. Obstruction to cardiac outflow may alter myocardial development, resulting in progressive ventricular hypoplasia. Alteration of oxygen content may profoundly influence pulmonary vascular and ductus arteriosus responses. Interference in blood flow and oxygen content may affect cerebral development as a result of inadequate oxygen or energy substrate supply. The circulatory effects may be gestational dependent, related to maturation of vascular responses in different organs. These prenatal influences of congenital cardiac defects may severely affect immediate, as well as longterm, postnatal prognosis and survival. This has stimulated the development of techniques for palliation of disturbed circulation during fetal life.

  13. Circulation Control in NASA's Vehicle Systems

    NASA Technical Reports Server (NTRS)

    Rich, Paul; McKinley, Bob; Jones, Greg

    2005-01-01

    Specific to the application of any technology to a vehicle, such as circulation control, it is important to understand the process that NASA is using to set its direction in research and development. To see how circulation control fits into any given NASA program requires the reader to understand NASA's Vehicle Systems (VS) Program. The VS Program recently celebrated its first year of existence with an annual review - an opportunity to look back on accomplishments, solicit feedback, expand national advocacy and support for the program, and recognize key contributions. Since its formation last year, Vehicle Systems has coordinated seven existing entities in a streamlined aeronautics research effort. It invests in vehicle technologies to protect the environment, make air travel more accessible and affordable for Americans, enable exploration through new aerospace missions, and augment national security. This past year has seen a series of valuable partnerships with industry, academia, and government agencies to make crucial aeronautics advances and assure America s future in flight.

  14. Genetically Encoded Voltage Indicators in Circulation Research

    PubMed Central

    Kaestner, Lars; Tian, Qinghai; Kaiser, Elisabeth; Xian, Wenying; Müller, Andreas; Oberhofer, Martin; Ruppenthal, Sandra; Sinnecker, Daniel; Tsutsui, Hidekazu; Miyawaki, Atsushi; Moretti, Alessandra; Lipp, Peter

    2015-01-01

    Membrane potentials display the cellular status of non-excitable cells and mediate communication between excitable cells via action potentials. The use of genetically encoded biosensors employing fluorescent proteins allows a non-invasive biocompatible way to read out the membrane potential in cardiac myocytes and other cells of the circulation system. Although the approaches to design such biosensors date back to the time when the first fluorescent-protein based Förster Resonance Energy Transfer (FRET) sensors were constructed, it took 15 years before reliable sensors became readily available. Here, we review different developments of genetically encoded membrane potential sensors. Furthermore, it is shown how such sensors can be used in pharmacological screening applications as well as in circulation related basic biomedical research. Potentials and limitations will be discussed and perspectives of possible future developments will be provided. PMID:26370981

  15. Potential acoustic benefits of circulation control rotors

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Cheeseman, I. C.

    1978-01-01

    The fundamental aeroacoustic mechanisms responsible for noise generation on a rotating blade are theoretically examined. Their contribution to the overall rotor sound pressure level is predicted. Results from a theory for airfoil trailing edge noise are presented. Modifications and extensions to other source theories are described where it is necessary to account for unique aspects of circulation control (CC) aerodynamics. The circulation control rotor (CCR), as embodied on an X-wing vertical takeoff and landing (VTOL) aircraft, is used as an example for computational purposes, although many of the theoretical results presented are generally applicable to other CC applications (such as low speed rotors, propellers, compressors, and fixed wing aircraft). Using the analytical models, it is shown that the utilization CC aerodynamics theoretically makes possible unprecedented advances in rotor noise reduction. For the X-wing VTOL these reductions appear to be feasible without incurring significant attendant performance and weight penalties.

  16. Loading capability of HVDC transformer bushings with restricted oil circulation for use in HVDC valve halls

    SciTech Connect

    Johansson, L.; Magnuson, B. ); Riffon, P. )

    1993-07-01

    The loading capability of a 500 kV HVDC transformer bushing is calculated with some unusual conditions: the internal oil circulation in the bushing is blocked at the flange level and the ambient air temperature is raised to 60 C. The theoretical model was verified with a full-scale heat run test on a 7.8 m long bushing. A 220 m[sup 3] insulated test chamber was required to enclose the test set-up.

  17. Calculation of molecular excitation rates

    NASA Technical Reports Server (NTRS)

    Flynn, George

    1993-01-01

    State-to-state collisional excitation rates for interstellar molecules observed by radio astronomers continue to be required to interpret observed line intensities in terms of local temperatures and densities. A problem of particular interest is collisional excitation of water which is important for modeling the observed interstellar masers. In earlier work supported by a different NASA Grant, excitation of water in collisions with He atoms was studied; after many years of successively more refined calculations that problem now seems to be well understood, and discrepancies with earlier experimental data for related (pressure broadening) phenomena are believed to reflect experimental errors. Because of interstellar abundances, excitation by H2, the dominant interstellar species, is much more important than excitation by He, although it has been argued that rates for excitation by these are similar. Under the current grant theoretical study of this problem has begun which is greatly complicated by the additional degrees of freedom which must be included both in determining the interaction potential and also in the molecular scattering calculation. We have now computed the interaction forces for nearly a thousand molecular geometries and are close to having an acceptable global fit to these points which is necessary for the molecular dynamics calculations. Also, extensive modifications have been made to the molecular scattering code, MOLSCAT. These included coding the rotational basis sets and coupling matrix elements required for collisions of an asymmetric top with a linear rotor. A new method for numerical solution of the coupled equations has been incorporated. Because of the long-ranged nature of the water-hydrogen interaction it is necessary to integrate the equations to rather large intermolecular separations, and the integration methods previously available in MOLSCAT are not ideal for such cases. However, the method used by Alexander in his HIBRIDON code is

  18. [Pulmonary alveolar microlithiasis. Study of pulmonary circulation].

    PubMed

    Orea Tejeda, A; Atencio, C; Sandoval, J; Lupi Herrera, E

    1982-01-01

    Pulmonary alveolar microlithiasis is a rare disease of unknown etiology which consists of alveolar deposit of calcium microspheres. We report the procedures for the diagnosis of this disease, as well as the hemodynamic features of the pulmonary circulation. Pulmonary arterial hypertension (PAH), and cor pulmonale were documented. The active and passive factors involved in PAH are analyzed. We conclude that alveolar hypoxia and estructural vascular changes play a major role in the genesis of PAH.

  19. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    SciTech Connect

    Not Available

    1992-02-01

    The objective of this DOE Cooperative Agreement is to conduct a cost-shared clean coal technology project to demonstrate the feasibility of circulating fluidized bed combustion technology and to evaluate economic, environmental, and operational benefits of CFB steam generators on a utility scale. At the conclusion of the Phase 2 program, testing related to satisfying these objectives was completed. Data analysis and reporting are scheduled for completion by October 1991. (VC)

  20. Deep circulations under simple classes of stratification

    NASA Technical Reports Server (NTRS)

    Salby, Murry L.

    1989-01-01

    Deep circulations where the motion field is vertically aligned over one or more scale heights are studied under barotropic and equivalent barotropic stratifications. The study uses two-dimensional equations reduced from the three-dimensional primitive equations in spherical geometry. A mapping is established between the full primitive equations and general shallow water behavior and the correspondence between variables describing deep atmospheric motion and those of shallow water behavior is established.

  1. Circulation method for depositing diffusion coatings

    NASA Astrophysics Data System (ADS)

    Arzamasov, B. N.; Simonov, V. N.

    2011-01-01

    The physicochemical fundamentals of directed mass transfer of coating elements with the help of heterogeneous chemical reactions occurring in a circulating gas flow successively washing the source of the coating element and the surface of the saturated part at nonisothermal and isothermal states of the reaction space are considered. Experiments and simulation are used for determining the effect of the process parameters on the thickness and phase composition of coatings on internal and external surfaces of machine parts and on their life.

  2. Atmospheric circulation of extrasolar giant planets

    NASA Astrophysics Data System (ADS)

    Showman, A. P.

    2012-12-01

    Of the many known extrasolar planets, over 100 have orbital semi-major axes less than 0.1 AU, and a significant fraction of these hot Jupiters and Neptunes are known to transit their stars, allowing them to be characterized with the Spitzer, Hubble, and groundbased telescopes. The stellar flux incident on these planets is expected to drive an atmospheric circulation that shapes the day-night temperature difference, infrared light curves, spectra, albedo, and atmospheric composition, and recent Spitzer infrared light curves show evidence for dynamical meteorology in these planets' atmospheres. Here, I will survey basic dynamical ideas and detailed 3D numerical models that illuminate the atmospheric circulation of these exotic, tidally locked planets. These models suggest that, generally, the circulation will be characterized by broad, fast zonal jets, with day-night temperature contrasts at the photosphere that may vary from small in some cases to large in others. I will discuss the dynamical mechanisms for maintaining the fast zonal jets that develop in these models, as well as the mechanisms for controlling the temperature patterns, including the day-night temperature contrasts. These mechanisms help to explain current observations, and they predict regime transitions for how the wind and temperature patterns should vary with the incident stellar flux, strength of atmospheric drag, and other parameters. These transitions are observable and in some cases are already becoming evident in the data. I will also compare the circulation of the hot Jupiters to that of young, massive giant planets being directly imaged around other stars, which will be the subject of a new observational vanguard over the next decade. To emphasize the similarities as well as differences, I will ground this discussion in our understanding of the more familiar atmospheric dynamical regime of Earth, as well as our "local" giant planets Jupiter, Saturn, Uranus, and Neptune.

  3. Atmospheric circulation of extrasolar giant planets

    NASA Astrophysics Data System (ADS)

    Showman, A. P.

    2011-12-01

    Of the many known extrasolar planets, nearly 200 have orbital semi-major axes less than 0.1 AU, and a significant fraction of these hot Jupiters and Neptunes are known to transit their stars, allowing them to be characterized with the Spitzer, Hubble, and groundbased telescopes. The stellar flux incident on these planets is expected to drive an atmospheric circulation that shapes the day-night temperature difference, infrared light curves, spectra, albedo, and atmospheric composition, and recent Spitzer infrared light curves show evidence for dynamical meteorology in these planets' atmospheres. Here, I will survey basic dynamical ideas and detailed 3D numerical models that illuminate the atmospheric circulation of these exotic, tidally locked planets. These models suggest that, generally, the circulation will be characterized by broad, fast zonal jets, with day-night temperature contrasts at the photosphere that may vary from small in some cases to large in others. I will discuss the dynamical mechanisms for maintaining the fast zonal jets that develop in these models, as well as the mechanisms for controlling the temperature patterns, including the day-night temperature contrasts. These mechanisms help to explain current observations, and they predict regime transitions for how the wind and temperature patterns should vary with the incident stellar flux, strength of atmospheric drag, and other parameters. These transitions are observable and in some cases are already becoming evident in the data. I will also compare the circulation of the hot Jupiters to that of young, massive giant planets being directly imaged around other stars, which will be the subject of a new observational vanguard over the next decade. To emphasize the similarities as well as differences, I will ground this discussion in our understanding of the more familiar atmospheric dynamical regime of Earth, as well as our "local" giant planets Jupiter, Saturn, Uranus, and Neptune.

  4. Meridional circulation in optically thick accretion disks

    NASA Technical Reports Server (NTRS)

    Cabot, W.; Savedoff, M. P.

    1982-01-01

    Thermal imbalances in stars due to rotation are known to drive mass motions in the meridional plane. A preliminary analytic investigation has been made of a similar effect in optically thick accretion disks using conventional thin-disk approximations. It is found that estimated circulation times can be as short as thermal timescales, resulting in rapid transport of heat and angular momentum. This indicates that the simple approximations commonly used are incomplete with regard to detailed, two-dimensional disk structure.

  5. Glider Observations of Circulation Around an Island

    DTIC Science & Technology

    2015-09-30

    large-scale wind field, and the oceanic general circulation in which the island is embedded. First, we plan to address the so- called “island rule...Figure 1). The gliders occupied two lines perpendicular to shore on the east side of the island. In addition to the standard Sea- Bird CTD and...of island wake effects to observe the difference in the eddy field on either side of the island. IMPACT/APPLICATIONS All temperature and

  6. Meridional Circulation in the Tropical North Atlantic

    DTIC Science & Technology

    1993-01-01

    nominally located at 1 I°N was carried out in March 1989. In this paper relative geostrophic velocities are computed from these data via the thermal wind...from these analysis techniques is presented, and indicates a North Brazil Current transport of nearly 12 Sv. Transports of the shallow waters are found...Schematic circulation patterns of the NADW and AABW are also presented. The deep waters of the western basin are dominated by a cyclonic recirculation

  7. Radioprotection calculations for MEGAPIE.

    PubMed

    Zanini, L

    2005-01-01

    The MEGAwatt PIlot Experiment (MEGAPIE) liquid lead-bismuth spallation neutron source will commence operation in 2006 at the SINQ facility of the Paul Scherrer Institut. Such an innovative system presents radioprotection concerns peculiar to a liquid spallation target. Several radioprotection issues have been addressed and studied by means of the Monte Carlo transport code, FLUKA. The dose rates in the room above the target, where personnel access may be needed at times, from the activated lead-bismuth and from the volatile species produced were calculated. Results indicate that the dose rate level is of the order of 40 mSv h(-1) 2 h after shutdown, but it can be reduced below the mSv h(-1) level with slight modifications to the shielding. Neutron spectra and dose rates from neutron transport, of interest for possible damage to radiation sensitive components, have also been calculated.

  8. CONVEYOR FOUNDATIONS CALCULATION

    SciTech Connect

    S. Romanos

    1995-03-10

    The purpose of these calculations is to design foundations for all conveyor supports for the surface conveyors that transport the muck resulting from the TBM operation, from the belt storage to the muck stockpile. These conveyors consist of: (1) Conveyor W-TO3, from the belt storage, at the starter tunnel, to the transfer tower. (2) Conveyor W-SO1, from the transfer tower to the material stacker, at the muck stockpile.

  9. Global Circulation and Impact of Plasmaspheric Plumes

    NASA Technical Reports Server (NTRS)

    Moore, Thomas E.; Fok, Mei-Ching; Chen, Sheng-Hsiem; Delcourt, Dominique C.; Fedder, Joel A.; Slinker, Steven P.

    2008-01-01

    We report results from the global circulation model of Lyon, Fedder, and Mobarry with an embedded model of the inner magnetosphere including the plasmasphere. The combination is used to initiate large numbers of representative protons on the geosynchronous orbit L shell, to assign particle weightings, to track their: subsequent trajectories in the 3D fields. This permits us to study the global circulation of plasmaspheric plumes and to compare these with Polar observations from the dayside magnetopause region . A range of events is studied from an isolated period of SBz in the solar wind,to a large storm sequence. We consider effects on circulating plasma reaching the dayside reconnection X-line, the population of the plasma sheet with ionospheric protons and the generation of ring current pressure from this source, compared with solar wind, polar wind, and auroral wind sources. We find that the transient plasmaspheric plume source is large in terms of total fluence, but of modest proportions in terms of contribution to the ring current. Implications of this and other results for improved space weather modeling and prediction will be discussed.

  10. Measurement of circulating vitamin D in man.

    PubMed

    Clemens, T L; Adams, J S; Nolan, J M; Holick, M F

    1982-06-03

    An assay for vitamin D consisting of high-pressure liquid chromatography (HPLC) and ultraviolet (UV) absorbance detection has been developed and used to measure circulating vitamin D concentrations in human subjects during summer and winter and after deliberate exposure to ultraviolet radiation. Extracts of 2-4 ml of serum were initially fractionated on silica Sep-Pak cartridges followed by reverse-phase HPLC and finally quantitated by UV-absorbance during straight-phase HPLC. Using these methods, we determined the normal range for circulating vitamin D in Boston subjects to be less than 0.5 ng/ml to 25 ng/ml (n = 30); subjects sampled during summer months had higher concentrations of vitamin D than those sampled during winter months. In subjects exposed to a single quantitative dose of ultraviolet radiation (UVR), large transient increases in circulating vitamin D3 were observed. Concentrations rose 30-50 fold over the first days after exposure before returning to basal levels by one week.

  11. The protein corona of circulating PEGylated liposomes.

    PubMed

    Palchetti, Sara; Colapicchioni, Valentina; Digiacomo, Luca; Caracciolo, Giulio; Pozzi, Daniela; Capriotti, Anna Laura; La Barbera, Giorgia; Laganà, Aldo

    2016-02-01

    Following systemic administration, liposomes are covered by a 'corona' of proteins, and preserving the surface functionality is challenging. Coating the liposome surface with polyethylene glycol (PEG) is the most widely used anti-opsonization strategy, but it cannot fully preclude protein adsorption. To date, protein binding has been studied following in vitro incubation to predict the fate of liposomes in vivo, while dynamic incubation mimicking in vivo conditions remains largely unexplored. The main aim of this investigation was to determine whether shear stress, produced by physiologically relevant dynamic flow, could influence the liposome-protein corona. The corona of circulating PEGylated liposome was thoroughly compared with that formed by incubation in vitro. Systematic comparison in terms of size, surface charge and quantitative composition was made by dynamic light scattering, microelectrophoresis and nano-liquid chromatography tandem mass spectrometry (nanoLC-MS/MS). Size of coronas formed under static vs. dynamic incubation did not appreciably differ from each other. On the other side, the corona of circulating liposomes was more negatively charged than its static counterpart. Of note, the variety of protein species in the corona formed in a dynamic flow was significantly wider. Collectively, these results demonstrated that the corona of circulating PEGylated liposomes can be considerably different from that formed in a static fluid. This seems to be a key factor to predict the biological activity of a liposomal formulation in a physiological environment.

  12. Ocean circulation on the North Australian Shelf

    NASA Astrophysics Data System (ADS)

    Schiller, Andreas

    2011-07-01

    The ocean circulation on Australia's Northern Shelf is dominated by the Monsoon and influenced by large-scale interannual variability. These driving forces exert an ocean circulation that influences the deep Timor Sea Passage of the Indonesian Throughflow, the circulation on the Timor and Arafura Shelves and, further downstream, the Leeuwin Current. Seasonal maxima of northeastward (southwestward) volume transports on the shelf are almost symmetric and exceed 10 6 m 3/s in February (June). The associated seasonal cycle of vertical upwelling from June to August south of 8.5°S and between 124°E and 137.5°E exceeds 1.5×10 6 m 3/s across 40 m depth. During El Niño events, combined anomalies from the seasonal means of high regional wind stresses and low inter-ocean pressure gradients double the northeastward volume transport on the North Australian Shelf to 1.5×10 6 m 3/s which accounts for 20% of the total depth-integrated transport across 124°E and reduce the total transport of the Indonesian Throughflow. Variability of heat content on the shelf is largely determined by Pacific and Indian Ocean equatorial wind stress anomalies with some contribution from local wind stress forcing.

  13. The Nature of Natural Languages.

    ERIC Educational Resources Information Center

    Pierce, Joe E.

    A variety of types of evidence are examined to help determine the true nature of "deep structure" and what, if any, implications this has for linguistic theory as well as culture theory generally. The evidence accumulated over the past century on the nature of phonetic and phonemic systems is briefly discussed, and the following areas of…

  14. PIC: Protein Interactions Calculator

    PubMed Central

    Tina, K. G.; Bhadra, R.; Srinivasan, N.

    2007-01-01

    Interactions within a protein structure and interactions between proteins in an assembly are essential considerations in understanding molecular basis of stability and functions of proteins and their complexes. There are several weak and strong interactions that render stability to a protein structure or an assembly. Protein Interactions Calculator (PIC) is a server which, given the coordinate set of 3D structure of a protein or an assembly, computes various interactions such as disulphide bonds, interactions between hydrophobic residues, ionic interactions, hydrogen bonds, aromatic–aromatic interactions, aromatic–sulphur interactions and cation–π interactions within a protein or between proteins in a complex. Interactions are calculated on the basis of standard, published criteria. The identified interactions between residues can be visualized using a RasMol and Jmol interface. The advantage with PIC server is the easy availability of inter-residue interaction calculations in a single site. It also determines the accessible surface area and residue-depth, which is the distance of a residue from the surface of the protein. User can also recognize specific kind of interactions, such as apolar–apolar residue interactions or ionic interactions, that are formed between buried or exposed residues or near the surface or deep inside. PMID:17584791

  15. PIC: Protein Interactions Calculator.

    PubMed

    Tina, K G; Bhadra, R; Srinivasan, N

    2007-07-01

    Interactions within a protein structure and interactions between proteins in an assembly are essential considerations in understanding molecular basis of stability and functions of proteins and their complexes. There are several weak and strong interactions that render stability to a protein structure or an assembly. Protein Interactions Calculator (PIC) is a server which, given the coordinate set of 3D structure of a protein or an assembly, computes various interactions such as disulphide bonds, interactions between hydrophobic residues, ionic interactions, hydrogen bonds, aromatic-aromatic interactions, aromatic-sulphur interactions and cation-pi interactions within a protein or between proteins in a complex. Interactions are calculated on the basis of standard, published criteria. The identified interactions between residues can be visualized using a RasMol and Jmol interface. The advantage with PIC server is the easy availability of inter-residue interaction calculations in a single site. It also determines the accessible surface area and residue-depth, which is the distance of a residue from the surface of the protein. User can also recognize specific kind of interactions, such as apolar-apolar residue interactions or ionic interactions, that are formed between buried or exposed residues or near the surface or deep inside.

  16. Computer-aided design of stripline ferrite junction circulators

    NASA Technical Reports Server (NTRS)

    Uzdy, Z.

    1980-01-01

    A general design procedure is presented for stripline Y-junction circulators employing solid dielectric between ground planes. The resonator design and impedance matching are derived in a form suitable for computer evaluation. The procedure is applicable to cases where either the circulator bandwidth or the ground plane spacing is specified. An experimental S-band switching circulator design illustrates the technique.

  17. Hadley circulations for zonally averaged heating centered off the equator

    NASA Technical Reports Server (NTRS)

    Lindzen, Richard S.; Hou, Arthur Y.

    1988-01-01

    Consistent with observations, it is found that moving peak heating even 2 deg off the equator leads to profound asymmetries in the Hadley circulation, with the winter cell amplifying greatly and the summer cell becoming negligible. It is found that the annually averaged Hadley circulation is much larger than the circulation forced by the annually averaged heating.

  18. 21 CFR 868.5250 - Breathing circuit circulator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Breathing circuit circulator. 868.5250 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5250 Breathing circuit circulator. (a) Identification. A breathing circuit circulator is a turbine device that is attached to a closed breathing...

  19. 21 CFR 868.5250 - Breathing circuit circulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Breathing circuit circulator. 868.5250 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5250 Breathing circuit circulator. (a) Identification. A breathing circuit circulator is a turbine device that is attached to a closed breathing...

  20. 21 CFR 868.5250 - Breathing circuit circulator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Breathing circuit circulator. 868.5250 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5250 Breathing circuit circulator. (a) Identification. A breathing circuit circulator is a turbine device that is attached to a closed breathing...

  1. 21 CFR 868.5250 - Breathing circuit circulator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Breathing circuit circulator. 868.5250 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5250 Breathing circuit circulator. (a) Identification. A breathing circuit circulator is a turbine device that is attached to a closed breathing...

  2. 21 CFR 868.5250 - Breathing circuit circulator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Breathing circuit circulator. 868.5250 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5250 Breathing circuit circulator. (a) Identification. A breathing circuit circulator is a turbine device that is attached to a closed breathing...

  3. 40 CFR 230.23 - Current patterns and water circulation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Current patterns and water circulation... Potential Impacts on Physical and Chemical Characteristics of the Aquatic Ecosystem § 230.23 Current patterns and water circulation. (a) Current patterns and water circulation are the physical movements...

  4. 26 CFR 1.173-1 - Circulation expenditures.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 3 2010-04-01 2010-04-01 false Circulation expenditures. 1.173-1 Section 1.173... Circulation expenditures. (a) Allowance of deduction. Section 173 provides for the deduction from gross income of all expenditures to establish, maintain, or increase the circulation of a newspaper, magazine,...

  5. Elevated Levels of Circulating DNA in Cardiovascular Disease Patients: Metagenomic Profiling of Microbiome in the Circulation

    PubMed Central

    Dinakaran, Vasudevan; Rathinavel, Andiappan; Pushpanathan, Muthuirulan; Sivakumar, Ramamoorthy; Gunasekaran, Paramasamy; Rajendhran, Jeyaprakash

    2014-01-01

    Cardiovascular diseases (CVDs) are the leading cause of death worldwide. An expanding body of evidence supports the role of human microbiome in the establishment of CVDs and, this has gained much attention recently. This work was aimed to study the circulating human microbiome in CVD patients and healthy subjects. The levels of circulating cell free DNA (circDNA) was higher in CVD patients (n = 80) than in healthy controls (n = 40). More specifically, the relative levels of circulating bacterial DNA and the ratio of 16S rRNA/β-globin gene copy numbers were higher in the circulation of CVD patients than healthy individuals. In addition, we found a higher circulating microbial diversity in CVD patients (n = 3) in comparison to healthy individuals (n = 3) by deep shotgun sequencing. At the phylum level, we observed a dominance of Actinobacteria in CVD patients, followed by Proteobacteria, in contrast to that in healthy controls, where Proteobacteria was predominantly enriched, followed by Actinobacteria. The circulating virome in CVD patients was enriched with bacteriophages with a preponderance of Propionibacterium phages, followed by Pseudomonas phages and Rhizobium phages in contrast to that in healthy individuals, where a relatively greater abundance of eukaryotic viruses dominated by Lymphocystis virus (LCV) and Torque Teno viruses (TTV) was observed. Thus, the release of bacterial and viral DNA elements in the circulation could play a major role leading to elevated circDNA levels in CVD patients. The increased circDNA levels could be either the cause or consequence of CVD incidence, which needs to be explored further. PMID:25133738

  6. Elevated levels of circulating DNA in cardiovascular disease patients: metagenomic profiling of microbiome in the circulation.

    PubMed

    Dinakaran, Vasudevan; Rathinavel, Andiappan; Pushpanathan, Muthuirulan; Sivakumar, Ramamoorthy; Gunasekaran, Paramasamy; Rajendhran, Jeyaprakash

    2014-01-01

    Cardiovascular diseases (CVDs) are the leading cause of death worldwide. An expanding body of evidence supports the role of human microbiome in the establishment of CVDs and, this has gained much attention recently. This work was aimed to study the circulating human microbiome in CVD patients and healthy subjects. The levels of circulating cell free DNA (circDNA) was higher in CVD patients (n = 80) than in healthy controls (n = 40). More specifically, the relative levels of circulating bacterial DNA and the ratio of 16S rRNA/β-globin gene copy numbers were higher in the circulation of CVD patients than healthy individuals. In addition, we found a higher circulating microbial diversity in CVD patients (n = 3) in comparison to healthy individuals (n = 3) by deep shotgun sequencing. At the phylum level, we observed a dominance of Actinobacteria in CVD patients, followed by Proteobacteria, in contrast to that in healthy controls, where Proteobacteria was predominantly enriched, followed by Actinobacteria. The circulating virome in CVD patients was enriched with bacteriophages with a preponderance of Propionibacterium phages, followed by Pseudomonas phages and Rhizobium phages in contrast to that in healthy individuals, where a relatively greater abundance of eukaryotic viruses dominated by Lymphocystis virus (LCV) and Torque Teno viruses (TTV) was observed. Thus, the release of bacterial and viral DNA elements in the circulation could play a major role leading to elevated circDNA levels in CVD patients. The increased circDNA levels could be either the cause or consequence of CVD incidence, which needs to be explored further.

  7. A detailed evaluation of the stratospheric heat budget: 2. Global radiation balance and diabatic circulations

    NASA Astrophysics Data System (ADS)

    Mlynczak, Martin G.; Mertens, Christopher J.; Garcia, Rolando R.; Portmann, Robert W.

    1999-03-01

    We present a detailed evaluation of radiative heating, radiative cooling, net heating, global radiation balance, radiative relaxation times, and diabatic circulations in the stratosphere using temperature and minor constituent data provided by instruments on the Upper Atmosphere Research Satellite (UARS) between 1991 and 1993 and by the limb infrared monitor of the stratosphere (LIMS) instrument which operated on the Nimbus-7 spacecraft in 1978-1979. Included in the calculations are heating due to absorption of solar radiation from ultraviolet through near-infrared wavelengths and radiative cooling due to emission by carbon dioxide, water vapor, and ozone from 0 to 3000 cm-1 (∞ - 3.3 μm). Infrared radiative effects of Pinatubo aerosols are also considered in some detail. In general, we find the stratosphere to be in a state of global mean radiative equilibrium on monthly timescales to within the uncertainty of the satellite-provided measurements. Radiative relaxation times are found to be larger in the lower stratosphere during UARS than LIMS because of the presence of Pinatubo aerosols. The meridional circulations in the upper stratosphere as diagnosed from the calculated fields of net heating are generally stronger in the UARS period than during the LIMS period, while the lower stratosphere meridional circulations are stronger during the LIMS period. A climatology of these calculations is available to the community via a World Wide Web interface described herein.

  8. Thermal loading of natural streams

    USGS Publications Warehouse

    Jackman, Alan P.; Yotsukura, Nobuhiro

    1977-01-01

    The impact of thermal loading on the temperature regime of natural streams is investigated by mathematical models, which describe both transport (convection-diffusion) and decay (surface dissipation) of waste heat over 1-hour or shorter time intervals. The models are derived from the principle of conservation of thermal energy for application to one- and two-dimensional spaces. The basic concept in these models is to separate water temperature into two parts, (1) excess temperature due to thermal loading and (2) natural (ambient) temperature. This separation allows excess temperature to be calculated from the models without incoming radiation data. Natural temperature may either be measured in prototypes or calculated from the model. If use is made of the model, however, incoming radiation is required as input data. Comparison of observed and calculated temperatures in seven natural streams shows that the models are capable of predicting transient temperature regimes satisfactorily in most cases. (Woodard-USGS)

  9. Natural disasters.

    PubMed

    Cullen, J M

    1980-09-01

    This presentation covers the various types of natural disasters which are faced by investigators throughout the world. Each geophysical substance is discussed, including earth, air and water, and secondary effects including fire. Additionally, four myths associated with disasters are reviewed.

  10. Chaotic Oscillations of the Martian Atmospheric Circulation.

    NASA Astrophysics Data System (ADS)

    Pankine, A. A.; Ingersoll, A. P.

    1998-09-01

    We present a simplified model of the global circulation-dust interaction aimed at explaining the interannual variability of martian global dust storms. The model is described by the system of the Lorenz equations (Lorenz, 1963) with an additional term that represents seasonal forcing.The results of the Mars GCM simulations (Pollack et al., 1990) are used to define the values of the model parameters. For some parameter values the model exhibits rapid oscillations in atmospheric circulation and dust loading during early summer in both hemispheres. The oscillations are non periodic and may represent the observed global dust storms. The solutions are consistent with the time of occurrence and the duration of the observed global dust storms, but contradict the occurrence of global storms only in the southern hemisphere. We suggest that physical processes not related to the global circulation are responsible for these discrepancies. These processes may include redistribution of the dust on the surface (Haberle, 1986) or water ice condensation on the dust particles (Clancy et al., 1996). The duration of the dust storms in our model is independent of the dust settling time, suggesting that the global circulation plays important role in the dust storm decay. We think that the results of our simulations may help in distinguishing between processes that are crucial for the Martian dust cycle and can provide guidance for the Mars GCM simulations. References: Lorenz, E. N., 1963. Deterministic non periodic flow, J. Atmos. Sci., 20, 130-141. Pollack, J. B., R. M. Haberle, J. Schaeffer, H. Lee, 1990. Simulation of the general circulation of the martian atmosphere. 1. Polar process. J. Geophys. Res., 95(B2), 1473- 1447. Clancy, R. T., A. W. Grossman, M. J. Wolff, P. B. James, D. J. Rudy, Y. N. Billawala, B. J. Sandor, S. W. Lee, and D. O. Muhleman, 1996. Water vapor saturation at low altitudes around Mars aphelion: a key to Mars climate? Icarus, 122, 36 62. Haberle, R. M., 1986

  11. Circulating interleukin-6 and rheumatoid arthritis

    PubMed Central

    Li, Bing; Xiao, Yu; Xing, Dan; Ma, Xin-long; Liu, Jun

    2016-01-01

    Abstract Interleukin-6 (IL-6), as a pleiotropic cytokine, has been demonstrated to be closely associated with the pathogenisis of rheumatoid arthritis (RA). However, whether this association is causal or not remains unclear, because of the multifactorial role of IL-6 and related confounding factors. We aimed to evaluate the causal relevance between circulating IL-6 levels and the risk of RA through meta-analytical Mendelian randomization approach. IL-6 gene -174G/C variant was selected as an instrument in this Mendelian randomization meta-analysis. Article identification and data collection were conducted in duplicate and independently by 2 authors. The STATA software was used for data analysis. In total, 15 and 5 articles on the association of the -174G/C variant with RA risk and circulating IL-6 level, respectively, were included. The overall analysis showed that C allelic and GC+CC genotype were significantly with 1.59-fold (95% CI: 1.19–2.14) and 1.63-fold (95% CI: 1.17–2.26) increased risk of developing RA, respectively. Asian populations showed stronger association with 4.55-fold (95% CI: 1.62–12.75), 1.84-fold (95% CI: 1.13–2.99), and 4.69-fold (95% CI: 1.68–13.14) increased RA risk in carriers of -174C allelic, CC, and GC+CC genotype, respectively. Carriers of GC+CC genotype showed significant reduction in the circulating IL-6 level compared with GG carriers (WMD = −0.77; 95% CI: −1.16 to −0.38; P = 0.000) in overall populations. Mendelian randomization presented 6% and 22% increased risk of RA with 0.1 pg/mL reduction of circulating IL-6 level in overall and Asian populations, respectively. This Mendelian randomization meta-analysis demonstrated that the long-term genetically reduced circulating IL-6 level might be causally related to a higher risk of RA, especially in Asian populations. PMID:27281095

  12. [Natural disasters].

    PubMed

    Smolka, A

    1988-07-01

    The attempt is made to illustrate the role played by natural disasters in the history of the earth and mankind by examples of past catastrophes. Subsequently, the earthquake of Tangshan/China in 1976 and the hypothetical scenario of a repeat of the 1906 San Francisco earthquake in a modern setting serve as a basis for discussion of the significance of natural disasters in modern times.

  13. Revelations of a stratospheric circulation: The dynamical transport of hydrocarbons in the stratosphere of Uranus

    SciTech Connect

    McMillan, W.W.

    1992-01-01

    Observations by the Ultraviolet Spectrometer (UVS) onboard the Voyager 2 spacecraft revealed that above the 1 mb level, the mixing ratios of CH[sub 4], C[sub 2]H[sub 2], and C[sub 2]H[sub 6] are at least 10-100 times larger at the equator than at the south pole. In addition, the Voyager 2 Infrared Interferometric Spectrometer (IRIS) measured small meridional temperature gradients at the tropopause (60-200 mb) and in the upper troposphere (200-1000 mb) of Uranus. These temperature gradients result from a weak meridional circulation in the Uranian troposphere which penetrates into the stratosphere with upwelling at low southern latitudes and polar subsidence (vertical velocities [approximately]10[sup [minus]6] m/s, meridional velocities [approximately]10[sup [minus]3] m/s). The role of the zonally-averaged, meridional stratospheric circulation in determining the distribution of hydrocarbons in the stratosphere (0.1-100 mb) of Uranus is investigated with a 2-dimensional photochemical transport model. The stratospheric circulation is calculated with a linear, zonally-symmetric model with Newtonian cooling and Rayleigh friction similar to that used by Flaser et al. (1987). Operator-splitting is utilized to numerically solve the continuity equations for trace species in the stratosphere of Uranus. It is determined that advective transport by the stratospheric circulation can account for the essential observed meridional variation of stratospheric hydrocarbon abundances. However, vertical transport by eddy and molecular diffusion is required to fit the inferred vertical distribution of hydrocarbons. The uniform eddy diffusion coefficient is constrained to 10 cm[sup 2]/s < K < 100 cm[sup 2]/s (i.e. constant in both altitude and latitude). The best fit model has a meridional circulation three times stronger than the circulation of Flaser et al. and a weak uniform eddy diffusion coefficient, K = 100 cm[sup 2]/s.

  14. Genetic Predictors of Circulating 25-Hydroxyvitamin D and Risk of Colorectal Cancer

    PubMed Central

    Hiraki, Linda T; Qu, Conghui; Hutter, Carolyn M; Baron, John A; Berndt, Sonja I; Bézieau, Stéphane; Brenner, Hermann; Caan, Bette J; Casey, Graham; Chang-Claude, Jenny; Chanock, Stephen J; Conti, David V; Duggan, David; Fuchs, Charles S; Gallinger, Steven; Giovannucci, Edward; Harrison, Tabitha A; Hayes, Richard; Hazra, Aditi; Henderson, Brian; Hoffmeister, Michael; Hopper, John L; Hudson, Thomas J; Jenkins, Mark A; Küry, Sébastien; Le Marchand, Loic; Lemire, Mathieu; Ma, Jing; Manson, JoAnn E; Nan, Hongmei; Newcomb, Polly A; Ng, Kimmie; Potter, John D; Schoen, Robert E; Schumacher, Fredrick; Seminara, Daniela; Slattery, Martha L; Wactawski-Wende, Jean; White, Emily; Wu, Kana; Zanke, Brent W; Kraft, Peter; Peters, Ulrike; Chan, Andrew T

    2013-01-01

    Background Experimental evidence has demonstrated an anti-neoplastic role for vitamin D in the colon and higher circulating 25-hydroxyvitamin D (25[OH]D) levels are consistently associated with a lower risk of colorectal cancer (CRC). Genome-wide association studies have identified loci associated with levels of circulating 25(OH)D. The identified SNPs from four gene regions, collectively explain approximately 5% of the variance in circulating 25(OH)D. Methods We investigated whether six polymorphisms in GC, CYP2R1, CYP24A1 and DHCR7/NADSYN1, genes previously shown to be associated with circulating 25(OH)D levels, were associated with CRC risk in 10,061 cases and 12,768 controls drawn from 13 studies included in the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO) and Colon Cancer Family Registry (CCFR). We performed a meta-analysis of crude and multivariate-adjusted logistic regression models to calculate odds ratios and associated confidence intervals for SNPs individually, SNPs simultaneously, and for a vitamin D additive genetic risk score (GRS). Results We did not observe a statistically significant association between the 25(OH)D associated SNPs and CRC marginally, conditionally, or as a GRS, or for colon or rectal cancer separately or combined. Conclusions Our findings do not support an association between SNPs associated with circulating 25(OH)D and risk of CRC. Additional work is warranted to investigate the complex relationship between 25(OH)D and CRC risk. Impact There was no association observed between genetic markers of circulating 25(OH)D and CRC. These genetic markers account for a small proportion of the variance in 25(OH)D. PMID:23983240

  15. A Coupled General Circulation Model of the Archean Earth

    NASA Astrophysics Data System (ADS)

    Wolf, E. T.; Toon, O. B.

    2011-12-01

    We present results from a new coupled general circulation model suitable for deep paleoclimate studies. Particular interest is given to the faint young Sun paradox. The model is based on the Community Earth System Model maintained by the National Center for Atmospheric Research [1]. Prognostic atmosphere, ocean, land, ice, and hydrological cycle models are coupled. A new correlated-k radiative transfer model has been implemented allowing accurate flux calculations for anoxic atmospheres containing high concentrations of CO2 and CH4 [2, 3]. This model represents a significant improvement upon one-dimensional radiative-convective climate models used previously to study ancient climate [4]. Cloud and ice albedo feedbacks will be accurately quantified and new constraints on Archean surface temperatures will be revealed. References [1] Collins W.D. et al. "Description of the NCAR Community Atmosphere Model (CAM 3.0)." NCAR Technical Note, 2004. [2] Toon O.B., McKay, C.P., Ackerman, T.P. "Rapid Calculation of Radiative Heating Rates and Photodissociation Rates in Inhomogeneous Multiple Scattering Atmospheres." J. Geo. Res., 94(D13), 16287 - 16301, 1989. [3] Mlawer, E.J., et al. "Radiative transfer for inhomogeneous atmospheres: RRTM, a validated correlated-k model for the longwave." J. Geo. Res., 102(D14), 16663 - 16682, 1997. [4] Kasting J.F., Pollack, J.B., Crisp, D. "Effects of High CO2 Levels on Surface Temperature and Atmospheric Oxidation State of the Early Earth." J. Atm. Chem., 1, 403-428, 1984.

  16. Using Information Theory to Assess the Communicative Capacity of Circulating MicroRNA

    PubMed Central

    Finn, Nnenna A.; Searles, Charles D.

    2013-01-01

    The discovery of extracellular microRNAs (miRNAs) and their transport modalities (i.e. microparticles, exosomes, proteins and lipoproteins) has sparked theories regarding their role in intercellular communication. Here, we assessed the information transfer capacity of different miRNA transport modalities in human serum by utilizing basic principles of information theory. Zipf Statistics were calculated for each of the miRNA transport modalities identified in human serum. Our analyses revealed that miRNA-mediated information transfer is redundant, as evidenced by negative Zipf’s Statistics with magnitudes greater than one. In healthy subjects, the potential communicative capacity of miRNA in complex with circulating proteins was significantly lower than that of miRNA encapsulated in circulating microparticles and exosomes. Moreover, the presence of coronary heart disease significantly lowered the communicative capacity of all circulating miRNA transport modalities. To assess the internal organization of circulating miRNA signals, Shannon’s zero- and first-order entropies were calculated. Microparticles (MPs) exhibited the lowest Shannon entropic slope, indicating a relatively high capacity for information transfer. Furthermore, compared to the other miRNA transport modalities, MPs appeared to be the most efficient at transferring miRNA to cultured endothelial cells. Taken together, these findings suggest that although all transport modalities have the capacity for miRNA-based information transfer, MPs may be the simplest and most robust way to achieve miRNA-based signal transduction in sera. This study presents a novel method for analyzing the quantitative capacity of miRNA-mediated information transfer while providing insight into the communicative characteristics of distinct circulating miRNA transport modalities. PMID:23994137

  17. Using information theory to assess the communicative capacity of circulating microRNA.

    PubMed

    Finn, Nnenna A; Searles, Charles D

    2013-10-11

    The discovery of extracellular microRNAs (miRNAs) and their transport modalities (i.e., microparticles, exosomes, proteins and lipoproteins) has sparked theories regarding their role in intercellular communication. Here, we assessed the information transfer capacity of different miRNA transport modalities in human serum by utilizing basic principles of information theory. Zipf Statistics were calculated for each of the miRNA transport modalities identified in human serum. Our analyses revealed that miRNA-mediated information transfer is redundant, as evidenced by negative Zipf's Statistics with magnitudes greater than one. In healthy subjects, the potential communicative capacity of miRNA in complex with circulating proteins was significantly lower than that of miRNA encapsulated in circulating microparticles and exosomes. Moreover, the presence of coronary heart disease significantly lowered the communicative capacity of all circulating miRNA transport modalities. To assess the internal organization of circulating miRNA signals, Shannon's zero- and first-order entropies were calculated. Microparticles (MPs) exhibited the lowest Shannon entropic slope, indicating a relatively high capacity for information transfer. Furthermore, compared to the other miRNA transport modalities, MPs appeared to be the most efficient at transferring miRNA to cultured endothelial cells. Taken together, these findings suggest that although all transport modalities have the capacity for miRNA-based information transfer, MPs may be the simplest and most robust way to achieve miRNA-based signal transduction in sera. This study presents a novel method for analyzing the quantitative capacity of miRNA-mediated information transfer while providing insight into the communicative characteristics of distinct circulating miRNA transport modalities.

  18. Natural Flow Air Cooled Photovoltaics

    NASA Astrophysics Data System (ADS)

    Tanagnostopoulos, Y.; Themelis, P.

    2010-01-01

    Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. We performed experiments using a prototype based on three silicon photovoltaic modules placed in series to simulate a typical sloping building roof with photovoltaic installation. In this system the air flows through a channel on the rear side of PV panels. The potential for increasing the heat exchange from the photovoltaic panel to the circulating air by the addition of a thin metal sheet (TMS) in the middle of air channel or metal fins (FIN) along the air duct was examined. The operation of the device was studied with the air duct closed tightly to avoid air circulation (CLOSED) and the air duct open (REF), with the thin metal sheet (TMS) and with metal fins (FIN). In each case the experiments were performed under sunlight and the operating parameters of the experimental device determining the electrical and thermal performance of the system were observed and recorded during a whole day and for several days. We collected the data and form PV panels from the comparative diagrams of the experimental results regarding the temperature of solar cells, the electrical efficiency of the installation, the temperature of the back wall of the air duct and the temperature difference in the entrance and exit of the air duct. The comparative results from the measurements determine the improvement in electrical performance of the photovoltaic cells because of the reduction of their temperature, which is achieved by the naturally circulating air.

  19. Lightweight Magnetic Cooler With a Reversible Circulator

    NASA Technical Reports Server (NTRS)

    Chen, Weibo; McCormick, John

    2011-01-01

    A design of a highly efficient and lightweight space magnetic cooler has been developed that can continuously provide remote/distributed cooling at temperatures in the range of 2 K with a heat sink at about 15 K. The innovative design uses a cryogenic circulator that enables the cooler to operate at a high cycle frequency to achieve a large cooling capacity. The ability to provide remote/distributed cooling not only allows flexible integration with a payload and spacecraft, but also reduces the mass of the magnetic shields needed. The active magnetic regenerative refrigerator (AMRR) system is shown in the figure. This design mainly consists of two identical magnetic regenerators surrounded by their superconducting magnets and a reversible circulator. Each regenerator also has a heat exchanger at its warm end to reject the magnetization heat to the heat sink, and the two regenerators share a cold-end heat exchanger to absorb heat from a cooling target. The circulator controls the flow direction, which cycles in concert with the magnetic fields, to facilitate heat transfer. Helium enters the hot end of the demagnetized column, is cooled by the refrigerant, and passes into the cold-end heat exchanger to absorb heat. The helium then enters the cold end of the magnetized column, absorbing heat from the refrigerant, and enters the hot-end heat exchanger to reject the magnetization heat. The efficient heat transfer in the AMRR allows the system to operate at a relatively short cycle period to achieve a large cooling power. The key mechanical components in the magnetic cooler are the reversible circulator and the magnetic regenerators. The circulator uses non-contacting, self-acting gas bearings and clearance seals to achieve long life and vibration- free operation. There are no valves or mechanical wear in this circulator, so the reliability is predicted to be very high. The magnetic regenerator employs a structured bed configuration. The core consists of a stack of thin

  20. Role of wetlands in attenuation of storm surges using coastal circulation model (ADCIRC), Chesapeake Bay region

    NASA Astrophysics Data System (ADS)

    Deb, Mithun; Ferreira, Celso; Lawler, Seth

    2014-05-01

    The Chesapeake Bay, Virginia is subject to storm surge from extreme weather events nearly year-round; from tropical storms and hurricanes during the summer and fall, (e.g., hurricanes Isabel [2003] and Sandy [2012]), and from nor'easters during the winter (e.g., winter storms Nemo and Saturn [2013]). Coastal wetlands can deliver acute fortification against incoming hurricane storm surges. Coastal wetlands and vegetation shape the hydrodynamics of storm surge events by retaining water and slowing the propagation of storm surge, acting as a natural barrier to flooding. Consequently, a precise scheme to quantify the effect of wetlands on coastal surge levels was also prerequisite. Two wetland sites were chosen in the Chesapeake Bay region for detailed cataloging of vegetation characteristics, including: height, stem diameter, and density. A framework was developed combining these wetlands characterizations with numerical simulations. Storms surges were calculated using Coastal circulation model (ADCIRC) coupled to a wave model (SWAN) forced by an asymmetric hurricane vortex model using an unstructured mesh (comprised of 1.8 million nodes) under a High Performance Computing environment. The Hurricane Boundary Layer (HBL) model was used to compute wind and pressure fields for historical tropical storms and for all of the synthetic storms. Wetlands were characterized in the coupled numerical models by bathymetric and frictional resistance. Multiple model simulations were performed using historical hurricane data and hypothetical storms to compare the predicted storm surge inundation resulting from various levels of wetlands expansion or reduction. The results of these simulations demonstrate the efficacy of wetlands in storm surge attenuation and also the outcome will scientifically support planning of wetlands restoration projects with multi-objective benefits for society.