Science.gov

Sample records for natural circulation calculations

  1. Independent review of SCDAP/RELAP5 natural circulation calculations

    SciTech Connect

    Martinez, G.M.; Gross, R.J.; Martinez, M.J.; Rightley, G.S.

    1994-01-01

    A review and assessment of the uncertainties in the calculated response of reactor coolant system natural circulation using the SCDAP/RELAP5 computer code were completed. The SCDAP/RELAP5 calculation modeled a station blackout transient in the Surry nuclear power plant and concluded that primary system depressurization from natural circulation induced primary system failure is more likely than previously thought.

  2. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    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.

  4. 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)

  5. 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.

  6. Numerical Issues for Circulation Control Calculations

    NASA Technical Reports Server (NTRS)

    Swanson, Roy C., Jr.; Rumsey, Christopher L.

    2006-01-01

    Steady-state and time-accurate two-dimensional solutions of the compressible Reynolds-averaged Navier- Stokes equations are obtained for flow over the Lockheed circulation control (CC) airfoil and the General Aviation CC (GACC) airfoil. Numerical issues in computing circulation control flows such as the effects of grid resolution, boundary and initial conditions, and unsteadiness are addressed. For the Lockheed CC airfoil computed solutions are compared with detailed experimental data, which include velocity and Reynolds stress profiles. Three turbulence models, having either one or two transport equations, are considered. Solutions are obtained on a sequence of meshes, with mesh refinement primarily concentrated on the airfoil circular trailing edge. Several effects related to mesh refinement are identified. For example, sometimes sufficient mesh resolution can exclude nonphysical solutions, which can occur in CC airfoil calculations. Also, sensitivities of the turbulence models with mesh refinement are discussed. In the case of the GACC airfoil the focus is on the difference between steady-state and time-accurate solutions. A specific objective is to determine if there is self-excited vortex shedding from the jet slot lip.

  7. Code System for Calculating the Nonlinear Transient Behavior of a Natural Circulation U-Tube Steam Generator with Its Main Steam System.

    2000-04-20

    Version 00 The code is based on a non-linear theoretical model describing the steady-state and transient behavior of a vertical natural-circulation U-tube steam generator together with its main steam system. The steam generator is considered to consist of a heat exchange section, a top plenum, a down-comer region and a main steam system (with a sequence of relief and/or safety valves, isolation, bypass, turbine-trip and turbine-control valves and a steam turbine). Possible perturbations from outsidemore » can be: inlet water temperature, inlet water mass flow and system pressure on the primary side, feedwater temperature, feed-water mass flow and outlet steam mass flow disturbed by actions of the different valves within the main steam system on the secondary side.« less

  8. Severe accident natural circulation studies at the INEL

    SciTech Connect

    Bayless, P.D.; Brownson, D.A.; Dobbe, C.A.; Jones, K.R.; O`Brien, J.E.; Pafford, D.J.; Schlenker, L.D.; Tung, V.X.

    1995-02-01

    Severe accident natural circulation flows have been investigated at the Idaho National Engineering Laboratory to better understand these flows and their potential impacts on the progression of a pressurized water reactor severe accident. Parameters affecting natural circulation in the reactor vessel and hot legs were identified and ranked based on their perceived importance. Reviews of the scaling of the 1/7-scale experiments performed by Westinghouse were undertaken. RELAP5/MOD3 calculations of two of the experiments showed generally good agreement between the calculated and observed behavior. Analyses of hydrogen behavior in the reactor vessel showed that hydrogen stratification is not likely to occur, and that an initially stratified layer of hydrogen would quickly mix with a recirculating steam flow. An analysis of the upper plenum behavior in the Three Mile Island, Unit 2 reactor concluded that vapor temperatures could have been significantly higher than the temperatures seen by the control rod drive lead screws, supporting the premise that a strong natural circulation flow was likely present during the accident. SCDAP/RELAP5 calculations of a commercial pressurized water reactor severe accident without operator actions showed that the natural circulation flows enhance the likelihood of ex-vessel piping failures long before failure of the reactor vessel lower head.

  9. 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.

  10. Numerical simulation of losses along a natural circulation helium loop

    NASA Astrophysics Data System (ADS)

    Knížat, Branislav; Urban, František; Mlkvik, Marek; RidzoÅ, František; Olšiak, Róbert

    2016-06-01

    A natural circulation helium loop appears to be a perspective passive method of a nuclear reactor cooling. When designing this device, it is important to analyze the mechanism of an internal flow. The flow of helium in the loop is set in motion due to a difference of hydrostatic pressures between cold and hot branch. Steady flow at a requested flow rate occurs when the buoyancy force is adjusted to resistances against the flow. Considering the fact that the buoyancy force is proportional to a difference of temperatures in both branches, it is important to estimate the losses correctly in the process of design. The paper deals with the calculation of losses in branches of the natural circulation helium loop by methods of CFD. The results of calculations are an important basis for the hydraulic design of both exchangers (heater and cooler). The analysis was carried out for the existing model of a helium loop of the height 10 m and nominal heat power 250 kW.

  11. ESBWR - Robust design for natural circulation and stability performance effectiveness

    SciTech Connect

    Alamgir, M. D.; Marquino, W.; Yang, J.; Saha, P.; Fennern, L.; Colby, M.

    2012-07-01

    ESBWR is a 4500 MWt Generation III+ natural circulation reactor with an array of robust design features and passive safety systems to deliver highly effective plant performance during normal operation and to keep the reactor safe during postulated transients and accidents. With the submittal of the latest revision of the Design Control Document (DCD) to US Nuclear Regulatory Commission, ESBWR is nearing the completion of the US design certification process. This paper focuses on the natural circulation-driven plant performance aspects during normal operation, and stability evaluation of the robust ESBWR design. The TRACG computer code is used for the analysis of ESBWR plant performance, safety analysis, and stability margins. The paper describes the evaluation of ESBWR stability performance during normal power operation including operation in the Core Power-Feed Water Temperature Operating Domain. For ESBWR the normal power operation condition has the highest power/flow ratio and is limiting from the perspective of stability. The paper includes results from detailed evaluation of the most limiting decay ratio for out-of-phase regional oscillations calculated by perturbing the core inlet flow rate in this out-of-phase mode about the line of symmetry for the azimuthal harmonic mode. The paper also summarizes the ESBWR regional mode stability evaluations during a limiting transient (Loss of Feedwater Heating), and during ATWS (Anticipated Transient without Scram). Nominal decay ratios of limiting Channel oscillation, Core wide oscillation and Regional oscillation are within the maximum acceptance criterion of 0.8, at 95% content and 95% confidence. These stability evaluation results indicate decay ratio is within design limits. The paper also describes the evaluation of ESBWR stability performance during plant startup, and summarizes the defense-in-depth stability solution for ESBWR. (authors)

  12. Vertical, natural circulation boiler for Tapada do Outeiro

    SciTech Connect

    1996-07-01

    With the new generation of high power, high temperature gas turbines, has come the demand for a tri-pressure reheat steam cycle to increase output and efficiency. As a result, designers are looking again at natural circulation heat recovery boilers, but with a vertical gas path. Tapada do Outeiro is probably the first project which has been specified with a vertical natural circulation configuration. Other boiler companies are experimenting with bypasses on the circulation pumps of tri-pressure boilers, so that natural circulation can be studied in a fully commercial environment. Effectively, the pumps are used at start-up, and then shut off so that the boiler effectively runs in natural circulation when stable conditions have been established. Although the plant is intended to run mainly for base load, it may also be used for load following with daily or weekly start. Aids to quick starting include provisions of weather damper to retain heat in the boiler overnight. There are no bypass stacks, but steam dumps to the condenser. The gas turbine exhausts straight into the cold boiler.

  13. A probabilistic method of calculating circulation-induced trends

    NASA Astrophysics Data System (ADS)

    Brox Nilsen, Irene; Stagge, James Howard; Merete Tallaksen, Lena

    2015-04-01

    The water cycle in Europe has changed substantially over the past three decades. Increasing runoff is observed during winter and at northern latitudes in particular. Spring and summer months, as well as southern latitudes, are facing drier conditions. To understand what is driving large-scale changes in runoff, we look into changes in precipitation and temperature and link these to changes in atmospheric circulation. Previous studies have used the method of trend ratios (Cahynová and Huth, 2009) to attribute precipitation and temperature trends to changes in the frequency of circulation types. A trend ratio is the ratio of hypothetical trend, i.e., the trend that would result due to changes in circulation type frequency only, to the observed trend. However, the method of trend ratios has two drawbacks. First, if the observed trend is small, division by a very low value results in a meaningless trend ratio and thus requires a cut-off value to keep the trend ratio within meaningful boundaries. Second, the method does not allow a comparison of the observed trend to the spread of possible outcomes, because the method of hypothetical trends is based on a deterministic model. We propose a new, more robust method for detecting the importance of circulation-induced changes in explaining the observed trends, which has the benefit of being a non-parametric statistical test that assesses the entire range of hypothetical trends. Instead of creating a hypothetical series by replacing the observation on a given day with the long-term climatic mean of a certain month and circulation type (as in the existing trend ratio method), the new approach replaces the observation on a given day with a random sample from the distribution of the variable for the given month and circulation type. The method introduces the possibility to assign a rejection rate, thus allowing statistical significance to be assessed. We apply the method on time series of precipitation and temperature from the

  14. 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.

  15. FFTF operating experience with sodium natural circulation: slides included

    SciTech Connect

    Burke, T.M.; Additon, S.L.; Beaver, T.R.; Midgett, J.C.

    1981-01-01

    The Fast Flux Test Facility (FFTF) has been designed for passive, back-up, safety grade decay heat removal utilizing natural circulation of the sodium coolant. This paper discusses the process by which operator preparation for this emergency operating mode has been assured, in paralled with the design verification during the FFTF startup and acceptance testing program. Over the course of the test program, additional insights were gained through the testing program, through on-going plant analyses and through general safety evaluations performed throughout the nuclear industry. These insights led to development of improved operator training material for control of decay heat removal during both forced and natural circulation as well as improvements in the related plant operating procedures.

  16. 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.

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

    SciTech Connect

    Chang H. Oh; Eung S. Kim

    2012-08-01

    Natural circulation patterns in the VHTR during a hypothetical air-ingress accident have been investigated using computational fluid dynamic (CFD) methods in order to compare results from the previous 1-D model which was developed using GAMMA code 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. CFD simulations were carried out as the steady-state calculation, and the boundary conditions were either assumed or provided from the 1-D GAMMA code results. Totally, 12 different cases have been reviewed, and many notable results have been obtained through in this work. According to the simulations, natural circulation patterns in the reactor were 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 about an order faster air-ingress speed (0.46 m/s in superficial velocity) than previously predicted 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, complicated natural circulation patterns are eventually expected to result in very complex graphite oxidations and corrosion behaviors.

  18. 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.

  19. 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.

  20. Natural circulation in a liquid metal one-dimensional loop

    NASA Astrophysics Data System (ADS)

    Tarantino, M.; De Grandis, S.; Benamati, G.; Oriolo, F.

    2008-06-01

    A wide use of pure lead, as well as its alloys (such as lead-bismuth, lead-lithium), is foreseen in several nuclear-related fields: it is studied as coolant in critical and sub-critical nuclear reactors, as spallation target for neutron generation in several applications and for tritium generation in fusion systems. In this framework, a new facility named NAtural CIrculation Experiment (NACIE), has been designed at ENEA-Brasimone Research Centre. NACIE is a rectangular loop, made by stainless steel pipes. It consists mainly of a cold and hot leg and an expansion tank installed on the top of the loop. A fuel bundle simulator, made by three electrical heaters placed in a triangular lattice, is located in the lower part of the cold leg, while a tube in tube heat exchanger is installed in the upper part of the hot leg. The adopted secondary fluid is THT oil, while the foreseen primary fluid for the tests is lead-bismuth in eutectic composition (LBE). The aim of the facility is to carry out experimental tests of natural circulation and collect data on the heat transfer coefficient (HTC) for heavy liquid metal flowing through rod bundles. The paper is focused on the preliminary estimation of the LBE flow rate along the loop. An analytical methodology has been applied, solving the continuity, momentum and energy transport equations under appropriate hypothesis. Moreover numerical simulations have been performed. The FLUENT 6.2 CFD code has been utilized for the numerical simulations. The main results carried out from the pre-tests simulations are illustrated in the paper, and a comparison with the theoretical estimations is done.

  1. 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.

  2. 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.

  3. Residual circulations calculated from satellite data: Their relations to observed temperature and ozone distributions

    NASA Technical Reports Server (NTRS)

    Geller, Marvin A.; Nash, Eric R.; Wu, Mao Fou; Rosenfield, Joan E.

    1990-01-01

    Monthly mean residual circulations were calculated from eight years of satellite data. The diabatic circulation is usually found to give a good approximation to the residual circulation, but this is not always the case. In particular, an example is shown at 60 deg S and 30 mbar where the diabatic and residual circulations show very different annual variations. Correlations between the vertical component of the residual circulation and temperature and ozone were computed. The computations indicate that yearly variations of temperatures in the tropics are under radiative control, except during stratospheric warmings. Interannual variations in seasonal mean temperatures are shown to be under dynamical control everywhere. Correlations between seasonal means of the vertical component of the residual circulation and ozone mixing ratios are consistent with what would be expected from the ozone variations being due to differences in the ozone transport, although transport effects cannot easily be distinguished from photochemical effects above the altitude of the ozone mixing ratio peak. Finally, variations in total ozone are examined in comparison with residual circulation variations. A one to two month phase lag is seen in the annual variation in the total ozone at 60 deg N with respect to the maximum downward residual motions. This phase lag is greater at 60 deg N than at 60 deg S. There is evidence at 60 deg S of a greater downward trend in the mean zonal ozone maxima than there is in the minima. A decreasing trend in the maximum descending motion is seen to accompany the ozone trend at 60 deg S.

  4. System model of a natural circulation integral test facility

    NASA Astrophysics Data System (ADS)

    Galvin, Mark R.

    The Department of Nuclear Engineering and Radiation Health Physics (NE/RHP) at Oregon State University (OSU) has been developing an innovative modular reactor plant concept since being initiated with a Department of Energy (DoE) grant in 1999. This concept, the Multi-Application Small Light Water Reactor (MASLWR), is an integral pressurized water reactor (PWR) plant that utilizes natural circulation flow in the primary and employs advanced passive safety features. The OSU MASLWR test facility is an electrically heated integral effects facility, scaled from the MASLWR concept design, that has been previously used to assess the feasibility of the concept design safety approach. To assist in evaluating operational scenarios, a simulation tool that models the test facility and is based on both test facility experimental data and analytical methods has been developed. The tool models both the test facility electric core and a simulated nuclear core, allowing evaluation of a broad spectrum of operational scenarios to identify those scenarios that should be explored experimentally using the test facility or design-quality multi-physics tools. Using the simulation tool, the total cost of experimentation and analysis can be reduced by directing time and resources towards the operational scenarios of interest.

  5. 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

  6. Nature of counterflow and circulation in vortex separators

    NASA Astrophysics Data System (ADS)

    Shtern, Vladimir N.; Borissov, Anatoli A.

    2010-08-01

    This paper focuses on the physical mechanism of elongated counterflows occurring in vortex tubes and hydrocyclones. To this end, a new solution to the Navier-Stokes equations is obtained which describes a flow pattern consisting of two through-flows and the global meridional circulation. One of the through-flows has U-shape geometry. It is shown that swirl decay due to fluid-wall friction induces both the U-shape through-flow and the circulation. The circulation does not deteriorate particle separation. The solution illustrates how the swirl-induced pressure distribution drives the counterflow and results in the paradoxical centrifugal stratification where the high-density fluid located at the periphery is hot while the low-density fluid located near the axis is cold.

  7. Assessment of RELAP5/MOD2 computer code against the Natural Circulation Test Data from Yong-Gwang Unit 2

    SciTech Connect

    Arne, N.; Cho, S.; Kim, H.J.

    1993-06-01

    The results of the RELAP5/MOD2 computer code simulation for the Natural Circulation Test in Yong-Gwang Unit 2 are analyzed here and compared with the plant operation data. The result of comparison reveals that the code calculation does present well the overall macroscopic behaviors of thermalhydraulic parameters in primary and secondary system compared with the plant operating data. The sensitivity study is performed to find out the effect of steam dump flow rate on the primary temperatures and it is found that the primary temperatures are very sensitive to the steam dump flow rate during the Natural Circulation. Because of the inherent uncertainties in the plant data, the assessment work is focussed on phenomena whereby the comparison between plant data and calculated data is based more on trends than on absolute values.

  8. [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.

  9. The Venus nitric oxide night airglow: Model calculations based on the Venus thermospheric general circulation model

    SciTech Connect

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

    1990-05-01

    Pioneer Venus (PV) orbiter ultraviolet spectrometer (OUVS) images of the nightside airglow in the (0, 1) {delta} band of nitric oxide showed a maximum whose average location was at 0200 local solar time just south of the equator. The average airglow brightness calculated over a portion of the nightside for 35 early orbits during the Pioneer Venus mission was a factor of 4 lower than this maximum. Recent recalibration of the PV OUVS instrument and reanalysis of the data yield new values for this statistical maximum (1.9 {plus minus} 0.6 kR) and the nightside average (400-460 {plus minus} 120 R) nightglow. This emission is produced by radiative recombination of N and O atoms transported from their source on the dayside to the nightside by the Venus thermospheric circulation. The Venus Thermospheric General Circulation Model (VTGCM) has been extended to incorporate odd nitrogen chemistry in order to examine the dynamical and chemical processes required to give rise to this emission. Its predictions of dayside N atom densities are also compared with empirical models based on Pioneer Venus measurements. Calculations are presented corresponding to OUVS data taken during solar maximum. The average production of nitrogen atoms on the dayside is about 9.0 {times} 10{sup 9} atoms cm{sup {minus}2} s{sup {minus}1}. Approximately 30% of this dayside source is required for transport to the nightside to yield the observed dark-disk nightglow features. The statistical location and intensity of the bright spot are well reproduced, as well as the altitude of the airglow layer. The importance of the large-scale transport and eddy diffusion on the global N({sup 4}S) distribution is also evaluated.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. Review of the natural circulation effect in the Vermont Yankee spent-fuel pool

    SciTech Connect

    Wheeler, C.L.

    1988-01-01

    A 7429-node, three-dimensional computer model of the Vermont Yankee spent-fuel pool was set up and run using the porous media model of the TEMPEST computer code. The results of this analysis show that natural circulation is sufficient to ensure adequate cooling, regardless of the loading pattern used or the orientation of the cooling system discharge nozzle.

  15. Design and measured performance of a solar chimney for natural circulation solar energy dryers

    SciTech Connect

    Ekechukwu, O.V.; Norton, B.

    1996-02-01

    An experimental solar chimney consisted of a cylindrical polyethylene-clad vertical chamber supported by steel framework and draped internally with a selectively absorbing surface. The performance of the chimney which was monitored extensively is reported. Issues related to the design and construction of solar chimneys for natural circulation solar energy dryers are discussed.

  16. Heat transfer to water from a vertical tube bundle under natural-circulation conditions. [PWR; BWR

    SciTech Connect

    Gruszczynski, M.J.; Viskanta, R.

    1983-01-01

    The natural circulation heat transfer data for longitudinal flow of water outside a vertical rod bundle are needed for developing correlations which can be used in best estimate computer codes to model thermal-hydraulic behavior of nuclear reactor cores under accident or shutdown conditions. The heat transfer coefficient between the fuel rod surface and the coolant is the key parameter required to predict the fuel temperature. Because of the absence of the required heat transfer coefficient data base under natural circulation conditions, experiments have been performed in a natural circulation loop. A seven-tube bundle having a pitch-to-diameter ratio of 1.25 was used as a test heat exchanger. A circulating flow was established in the loop, because of buoyancy differences between its two vertical legs. Steady-state and transient heat transfer measurements have been made over as wide a range of thermal conditions as possible with the system. Steady state heat transfer data were correlated in terms of relevant dimensionless parameters. Empirical correlations for the average Nusselt number, in terms of Reynolds number, Rayleigh number and the ratio of Grashof to Reynolds number are given.

  17. Density calculation and concentration scale conversions for natural waters

    NASA Astrophysics Data System (ADS)

    Monnin, Christophe

    1994-12-01

    A program is presented that calculates the density of a natural water from its composition. It is based on the recent modeling of the volumetric properties of natural waters at 25°C and 1 bar to high concentrations using Pitzer's equations. The required input is the concentrations of the major solutes of natural waters, that is Na, K, Ca, Mg, Cl, SO 4, HCO 3, and CO 3, expressed in any of the most widely used scales: molinity (grams or moles per kg of solution), molality (moles per kg of water), or molarity (moles or grams per liter). The output consists of the density of the solution, the partial molal volumes of the solutes, and a table in which the input concentrations are converted into all the scales as cited plus the solute mole fractions. The error in t he calculated seawater density is 0.00002 g/cm 3, but it increases to about 0.0004 g/cm 3 for dense brines. The program then is used to calculate the consequences of the approximation that natural waters behave as pure sodium chloride solutions, both for the computed density and for the concentration conversions.

  18. 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.

  19. A Parametric Approach To Mirror Natural Frequency Calculations

    NASA Astrophysics Data System (ADS)

    Nowak, William J.

    1984-01-01

    A hybrid analytical/graphical method is presented to calculate the fundamental natural frequency of rectangular mirrors mounted at 3 points. A NASTRAN assisted parametric approach was used to calculate the characteristic roots of the plate vibration equation for mirrors with aspect ratios ranging from 1.0 x 1.0 to 10.0 x 1.0. Also considered were simply supported boundary conditions at three mirror corner points or at two corner points on one edge and one point along the opposite edge. Experimental varification within 6.0% was achieved for the extreme case tested with approximately a +2.0% average experimental error overall.

  20. Validation of a plant dynamics code for 4S - Test analysis of natural circulation behavior

    SciTech Connect

    Sebe, F.; Horie, H.; Matsumiya, H.; Fanning, T. H.

    2012-07-01

    A plant transient dynamics code for a sodium-cooled fast reactor was developed by Toshiba. The code is used to evaluate the safety performance of Super-Safe, Small, and Simple reactor (4S) for Anticipated Operational Occurrences (AOOs), Design Basis Accident (DBA) and Beyond DBA (BDBA). The code is currently undergoing verification and validation (V and V). As one of the validation, test analysis of the Shutdown Heat Removal Test (SHRT)-17 performed in the Experimental Breeder Reactor (EBR)-II was conducted. The SHRT-17 is protected loss of flow test. The purpose of this validation is to confirm capability of the code to simulate natural circulation behavior of the plant. As a result, good agreements are shown between the analytical results and the measured data which were available from instrumented subassembly. The detailed validation result of the natural circulation behavior is described in this paper. (authors)

  1. 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.

  2. Thermal-hydraulic instabilities in natural circulation flow loops under supercritical conditions

    NASA Astrophysics Data System (ADS)

    Jain, Rachna

    In recent years, a growing interest has been generated in investigating the thermal hydraulics and flow stability phenomenon in supercritical natural circulation loops. These flow conditions are relevant to some of the innovative passive safety designs proposed for the Gen-IV Supercritical Water Reactor (SCWR) concepts. A computational model has been developed at UW Madison which provides a good basic simulation tool for the steady state and transient analysis of one dimensional natural circulation flow, and can be applied to conduct stability analysis. Several modifications and improvements were incorporated in an earlier numerical scheme before applying it to investigate the transient behavior of two experimental loops, namely, the supercritical water loop at UW-Madison and the supercritical carbon-dioxide (SCCO2) loop at Argonne National Laboratories. Although the model predicted development of instabilities for both SCW and SCCO2 loop which agrees with some previous work, the experiments conducted at SCCO2 loop exhibited stable behavior under similar conditions. To distinguish between numerical effects and physical processes, a linear stability approach has also been developed to investigate the stability characteristics associated with the natural circulation loop systems for various inlet conditions, input powers and geometries. The linear stability results for the SCW and SCCO2 loops exhibited differences with the corresponding transient simulations. This linear model also predicted the presence of instability in the SCCO 2 loop for certain high input powers contradictory to the experimental findings. Dimensionless parameters were proposed which would generalize the stability characteristics of the natural circulation flow loops under supercritical conditions.

  3. 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.

  4. A Analytical and Experimental Investigation of Natural Circulation Transients in a Model Pressurized Water Reactor

    NASA Astrophysics Data System (ADS)

    Massoud, Mahmoud

    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 head. 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 behaviour to variation of inputs such as secondary distribution and power transients.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. Natural circulation loop using liquid nitrogen for cryo-detection system

    SciTech Connect

    Choi, Yeon Suk

    2014-01-29

    The natural circulation loop is designed for the cryogenic insert in a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. Sensitivity is the key parameter of a FTICR mass spectrometer and the cryo-cooling of the pre-amplifier can reduce the thermal noise level and thereby improve the signal-to-noise ratio. The pre-amplifier consisted of non-magnetic materials is thermally connected to the cooling loop which is passing through the flange maintaining ultra-high vacuum in the ion cell. The liquid nitrogen passes through inside of the loop to cool the pre-amplifier indirectly. At the end, a cryocooler is located to re-condense nitrogen vapor generated due to the heat from the pre-amplifier. The circulating fluid removes heat from the pre-amplifier and transports it to the cryocooler or heat sink. In this paper the natural circulation loop for cryogenic pre-amplifier is introduced for improving the sensitivity of cryo-detector. In addition, the initial cool-down of the system by a cryocooler is presented and the temperature of the radiation shield is discussed with respect to the thickness of shield and the thermal radiation load.

  10. Numerical calculation of the transient behaviour of two pure cross-flow heat exchangers coupled by a circulating flow stream

    NASA Astrophysics Data System (ADS)

    Na Ranong, Chakkrit; Hapke, Jobst; Roetzel, Wilfried

    2010-11-01

    The transient thermal behaviour of a heat shifting system consisting of two pure cross-flow heat exchangers coupled by a circulating flow stream is studied theoretically. A suitable mathematical description of the system is based on the energy balance equation for general flow processes yielding a system of coupled hyperbolic partial differential equations in two dimensions. System responses to perturbations of inlet temperatures and mass flow rates are numerically calculated with an explicit finite difference method. A criterion for the generation of computational grids minimising effects of numerical dispersion and dissipation is applied to the system of coupled pure cross-flow heat exchangers which has not been considered up to now. Due to its internal circulation the coupled system shows a different behaviour compared to single cross-flow heat exchangers like inverse response and oscillatory behaviour to non-oscillating input signals.

  11. Circulating microparticles carry oxidation-specific epitopes and are recognized by natural IgM antibodies.

    PubMed

    Tsiantoulas, Dimitrios; Perkmann, Thomas; Afonyushkin, Taras; Mangold, Andreas; Prohaska, Thomas A; Papac-Milicevic, Nikolina; Millischer, Vincent; Bartel, Caroline; Hörkkö, Sohvi; Boulanger, Chantal M; Tsimikas, Sotirios; Fischer, Michael B; Witztum, Joseph L; Lang, Irene M; Binder, Christoph J

    2015-02-01

    Oxidation-specific epitopes (OSEs) present on apoptotic cells and oxidized low density lipoprotein (OxLDL) represent danger-associated molecular patterns that are recognized by different arcs of innate immunity, including natural IgM antibodies. Here, we investigated whether circulating microparticles (MPs), which are small membrane vesicles released by apoptotic or activated cells, are physiological carriers of OSEs. OSEs on circulating MPs isolated from healthy donors and patients with ST-segment elevation myocardial infarction (STE-MI) were characterized by flow cytometry using a panel of OSE-specific monoclonal antibodies. We found that a subset of MPs carry OSEs on their surface, predominantly malondialdehyde (MDA) epitopes. Consistent with this, a majority of IgM antibodies bound on the surface of circulating MPs were found to have specificity for MDA-modified LDL. Moreover, we show that MPs can stimulate THP-1 (human acute monocytic leukemia cell line) and human primary monocytes to produce interleukin 8, which can be inhibited by a monoclonal IgM with specificity for MDA epitopes. Finally, we show that MDA(+) MPs are elevated at the culprit lesion site of patients with STE-MI. Our results identify a subset of OSE(+) MPs that are bound by OxLDL-specific IgM. These findings demonstrate a novel mechanism by which anti-OxLDL IgM antibodies could mediate protective functions in CVD.

  12. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1990-05-01

    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.

  14. 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.

  15. Molecular electric moments calculated by using natural orbital functional theory.

    PubMed

    Mitxelena, Ion; Piris, Mario

    2016-05-28

    The molecular electric dipole, quadrupole, and octupole moments of a selected set of 21 spin-compensated molecules are determined employing the extended version of the Piris natural orbital functional 6 (PNOF6), using the triple-ζ Gaussian basis set with polarization functions developed by Sadlej, at the experimental geometries. The performance of the PNOF6 is established by carrying out a statistical analysis of the mean absolute errors with respect to the experiment. The calculated PNOF6 electric moments agree satisfactorily with the corresponding experimental data and are in good agreement with the values obtained by accurate ab initio methods, namely, the coupled-cluster single and doubles and multi-reference single and double excitation configuration interaction methods.

  16. Molecular electric moments calculated by using natural orbital functional theory

    NASA Astrophysics Data System (ADS)

    Mitxelena, Ion; Piris, Mario

    2016-05-01

    The molecular electric dipole, quadrupole, and octupole moments of a selected set of 21 spin-compensated molecules are determined employing the extended version of the Piris natural orbital functional 6 (PNOF6), using the triple-ζ Gaussian basis set with polarization functions developed by Sadlej, at the experimental geometries. The performance of the PNOF6 is established by carrying out a statistical analysis of the mean absolute errors with respect to the experiment. The calculated PNOF6 electric moments agree satisfactorily with the corresponding experimental data and are in good agreement with the values obtained by accurate ab initio methods, namely, the coupled-cluster single and doubles and multi-reference single and double excitation configuration interaction methods.

  17. [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.

  18. Natural Circulation and Linear Stability Analysis for Liquid-Metal Reactors with the Effect of Fluid Axial Conduction

    SciTech Connect

    Piyush Sabharwall; Qiao Wu; James J. Sienicki

    2012-06-01

    The effect of fluid axial thermal conduction on one-dimensional liquid metal natural circulation and its linear stability was performed through nondimensional analysis, steady-state assessment, and linear perturbation evaluation. The Nyquist criterion and a root-search method were employed to find the linear stability boundary of both forward and backward circulations. The study provided a relatively complete analysis method for one-dimensional natural circulation problems with the consideration of fluid axial heat conduction. The results suggest that fluid axial heat conduction in a natural circulation loop should be considered only when the modified Peclet number is {approx}1 or less, which is significantly smaller than the practical value of a lead liquid metal-cooled reactor.

  19. Human Circulating and Tissue-Resident CD56bright Natural Killer Cell Populations

    PubMed Central

    Melsen, Janine E.; Lugthart, Gertjan; Lankester, Arjan C.; Schilham, Marco W.

    2016-01-01

    Two human natural killer (NK) cell subsets are usually distinguished, displaying the CD56dimCD16+ and the CD56brightCD16−/+ phenotype. This distinction is based on NK cells present in blood, where the CD56dim NK cells predominate. However, CD56bright NK cells outnumber CD56dim NK cells in the human body due to the fact that they are predominant in peripheral and lymphoid tissues. Interestingly, within the total CD56bright NK cell compartment, a major phenotypical and functional diversity is observed, as demonstrated by the discovery of tissue-resident CD56bright NK cells in the uterus, liver, and lymphoid tissues. Uterus-resident CD56bright NK cells express CD49a while the liver- and lymphoid tissue-resident CD56bright NK cells are characterized by co-expression of CD69 and CXCR6. Tissue-resident CD56bright NK cells have a low natural cytotoxicity and produce little interferon-γ upon monokine stimulation. Their distribution and specific phenotype suggest that the tissue-resident CD56bright NK cells exert tissue-specific functions. In this review, we examine the CD56bright NK cell diversity by discussing the distribution, phenotype, and function of circulating and tissue-resident CD56bright NK cells. In addition, we address the ongoing debate concerning the developmental relationship between circulating CD56bright and CD56dim NK cells and speculate on the position of tissue-resident CD56bright NK cells. We conclude that distinguishing tissue-resident CD56bright NK cells from circulating CD56bright NK cells is a prerequisite for the better understanding of the specific role of CD56bright NK cells in the complex process of human immune regulation. PMID:27446091

  20. Stability Analysis of a natural circulation flow loop under supercritical condition

    NASA Astrophysics Data System (ADS)

    Jain, Rachna

    2005-11-01

    The stability of natural circulation flow loop geometry is under investigation in a specific thermo-dynamic region that encompasses the supercritical temperatures and pressures. This flow configuration is pertinent to the design of passive safety systems in some innovative reactor designs proposed for future generations of water-cooled nuclear reactors. Earlier studies employing both transient and linear stability approach considered supercritical natural circulation flow loop systems having a semi-closed boundary condition which required only the continuity in the pressure of the system around the loop. This is only true for loops that are connected to a large reservoir which theoretically can absorb any fluctuations in the flow velocity or temperatures and thus keep the inlet conditions fixed. A more realistic approach considered in the present study where a periodic boundary condition is imposed for such systems and requires continuity in the pressure, temperature and velocity as an essential boundary condition. With a highly non-linear equation of state specific to supercritical fluid and periodic boundary condition, the stability of this flow system is mathematically challenging to analyze.

  1. CFD analyses of natural circulation in the air-cooled reactor cavity cooling system

    SciTech Connect

    Hu, R.; Pointer, W. D.

    2013-07-01

    The Natural Convection Shutdown Heat Removal Test Facility (NSTF) is currently being built at Argonne National Laboratory, to evaluate the feasibility of the passive Reactor Cavity Cooling System (RCCS) for Next Generation Nuclear Plant (NGNP). CFD simulations have been applied to evaluate the NSTF and NGNP RCCS designs. However, previous simulations found that convergence was very difficult to achieve in simulating the complex natural circulation. To resolve the convergence issue and increase the confidence of the CFD simulation results, additional CFD simulations were conducted using a more detailed mesh and a different solution scheme. It is found that, with the use of coupled flow and coupled energy models, the convergence can be greatly improved. Furthermore, the effects of convection in the cavity and the effects of the uncertainty in solid surface emissivity are also investigated. (authors)

  2. A Transient Model of Induced Natural Circulation Thermal Cycling for Hydrogen Isotope Separation

    SciTech Connect

    SHADDAY, MARTIN

    2005-07-12

    The property of selective temperature dependence of adsorption and desorption of hydrogen isotopes by palladium is used for isotope separation. A proposal to use natural circulation of nitrogen to alternately heat and cool a packed bed of palladium coated beads is under active investigation, and a device consisting of two interlocking natural convection loops is being designed. A transient numerical model of the device has been developed to aid the design process. It is a one-dimensional finite-difference model, using the Boussinesq approximation. The thermal inertia of the pipe walls and other heat structures as well as the heater control logic is included in the model. Two system configurations were modeled and results are compared.

  3. 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.

  4. 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.

  5. Circulation of images and graphic practices in Renaissance natural history: the example of Conrad Gessner.

    PubMed

    Egmond, Florike; Kusukawa, Sachiko

    2016-01-01

    Conrad Gessner's Historia animalium is a compilation of information from a variety of sources: friends, correspondents, books, broadsides, drawings, as well as his own experience. The recent discovery of a cache of drawings at Amsterdam originally belonging to Gessner has added a new dimension for research into the role of images in Gessner's study of nature. In this paper, we examine the drawings that were the basis of the images in the volume of fishes. We uncovered several cases where there were multiple copies of the same drawing of a fish (rather than multiple drawings of the samefish), which problematizes the notion of unique "original" copies and their copies. While we still know very little about the actual mechanism of, or people involved in, commissioning or generating copies of drawings, their very existence suggests that the images functioned as an important medium in the circulation of knowledge in the early modern period.

  6. Helium I heat transfer in a small natural circulation loop with self-sustaining recondensation

    NASA Astrophysics Data System (ADS)

    Song, Yu; Four, Aurélien; Baudouy, Bertrand

    2014-01-01

    Heat transfer of helium I in a natural circulation loop is experimentally studied around atmospheric pressure. The test section of the loop has an inner diameter of 4 mm and a height of 23 cm and can be uniformly heated by wire heater. On top of the loop, a condenser is mounted and thermally connected to the second-stage of a 1.5 W at 4.2 K GM cryocooler. Helium can be recondensed in the condenser, where the pressure is regulated around the atmospheric pressure. While the dissipated heat flux is increased from 0 to 1 W, one encounters the different heat transfer regimes as single phase liquid convection, two phase nucleate boiling and single phase vapor convection. The wall superheat varies up to 11 K in the single phase vapor convection regime. The wall temperature measurement allows obtaining the boiling curve and determining the heat transfer coefficient.

  7. Circulation of images and graphic practices in Renaissance natural history: the example of Conrad Gessner.

    PubMed

    Egmond, Florike; Kusukawa, Sachiko

    2016-01-01

    Conrad Gessner's Historia animalium is a compilation of information from a variety of sources: friends, correspondents, books, broadsides, drawings, as well as his own experience. The recent discovery of a cache of drawings at Amsterdam originally belonging to Gessner has added a new dimension for research into the role of images in Gessner's study of nature. In this paper, we examine the drawings that were the basis of the images in the volume of fishes. We uncovered several cases where there were multiple copies of the same drawing of a fish (rather than multiple drawings of the samefish), which problematizes the notion of unique "original" copies and their copies. While we still know very little about the actual mechanism of, or people involved in, commissioning or generating copies of drawings, their very existence suggests that the images functioned as an important medium in the circulation of knowledge in the early modern period. PMID:27349032

  8. Conceptual design and thermal-hydraulic characteristics of natural circulation Boiling Water Reactors

    SciTech Connect

    Kataoka, Y.; Suzuki, H.; Murase, M. ); Horiuchi, T.; Miki, M. )

    1988-08-01

    A natural circulation boiling water reactor (BWR) with a rated capacity of 600 MW (electric) has been conceptually designed for small- and medium-sized light water reactors. The components and systems in the reactor are simplified by eliminating pumped recirculation systems and pumped emergency core cooling systems. Consequently, the volume of the reactor building is -- 50% of that for current BWRs with the same rated capacity; the construction period is also shorter. Its thermal-hydraulic characteristics, critical power ratio (CPR) and flow stability at steady state, decrease in the minimum CPR (..delta..MCPR) at transients, and the two-phase mixture level in the reactor pressure vessel (RPV) during accidents are investigated. The two-phase mixture level in the RPV during an accident does not decrease to lower than the top of the core; the core uncovery and heatup of fuel cladding would not occur during any loss-of-coolant accident.

  9. Experimental Study of a Nitrogen Natural Circulation Loop at Low Heat Flux

    NASA Astrophysics Data System (ADS)

    Baudouy, B.

    2010-04-01

    A natural convection circulation loop in liquid nitrogen, i.e. an open thermosiphon flow configuration, has been investigated experimentally near atmospheric pressure. The experiments were conducted on a 2 m high loop with a copper tube of 10 mm inner diameter uniformly heated over a length of 0.95 m. Evolution of the total mass flow rate of the loop and the pressure difference along the tube are described. We also report the boiling curves where single phase and two-phase flows are identified with increasing heat flux. We focus our heat transfer analysis on the single phase regime where mixed convection is encountered. A heat transfer coefficient correlation is proposed. We also examine the boiling incipience as a function of the tube height.

  10. 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.

  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. 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

  13. In vivo glucocorticoid effects on porcine natural killer cell activity and circulating leukocytes.

    PubMed

    Salak-Johnson, J L; McGlone, J J; Norman, R L

    1996-03-01

    Porcine natural killer (NK) cell cytotoxicity, plasma cortisol, total white blood cells (WBC), neutrophil:lymphocyte ratio (N:L), and circulating blood leukocytes were examined from pigs injected i.v. with either saline, ACTH, cortisol, or treated with metyrapone. Plasma cortisol increased (P < .05) after ACTH and cortisol treatments and decreased (P < .05) after metyrapone treatment; thus, treatments had the intended effects on in vivo cortisol concentrations. In Exp. 1, pigs were injected with either saline or ACTH at 0600 after the initial blood samples were taken (time 0). The ACTH had no effect (P > .10) on NK cytotoxicity. Pigs injected i.v. with ACTH had fewer lymphocytes and more neutrophils (P < .05) than control pigs. The N:L ratio was greater (P < .05) among ACTH-injected than among control pigs. In Exp. 2, pigs were injected i.v. with either saline or 40 or 400 micrograms of cortisol at 0600 after the initial blood samples were obtained (time 0). Cortisol at 40 micrograms had no effect (P > .10) on NK cytotoxicity. However, a 400-micrograms bolus of cortisol reduced (P < .05) NK cytotoxicity (control = 39.5, cortisol = 28.3% cytotoxicity, SEM = 3.7). Each dose of cortisol reduced (P < .05) circulating blood lymphocyte numbers. In Exp. 3, pigs were fed 1 g of metyrapone or no metyrapone the night before sampling. Blood samples were obtained at 0600, 0700, and 0800. Metyrapone reduced (P < .05) NK cytotoxicity (control = 28.6, metyrapone = 11.8%, SEM = 1.9). Pigs treated with metyrapone had greater (P < .05) numbers of neutrophils than control pigs. Numbers of lymphocytes were greater (P < .05) among control than among treated pigs. Pigs treated with metyrapone had a greater (P < .05) N:L ratio than control pigs. In conclusion, normal physiological concentrations or moderately increased blood cortisol concentrations did not influence NK activity, although leukocyte distributions were changed. We conclude that greatly increased or greatly decreased

  14. An analysis of the high-latitude thermospheric wind pattern calculated by a thermospheric general circulation model. I - Momentum forcing

    NASA Technical Reports Server (NTRS)

    Killeen, T. L.; Roble, R. G.

    1984-01-01

    A diagnostic processor (DP) was developed for analysis of hydrodynamic and thermodynamic processes predicted by the NCAR thermospheric general circulation model (TGCM). The TGCM contains a history file on the projected wind, temperature and composition fields at each grid point for each hour of universal time. The DP assimilates the history file plus ion drag tensors and drift velocities, specific heats, coefficients of viscosity, and thermal conductivity and calculates the individual forcing terms for the momentum and energy equations for a given altitude. Sample momentum forcings were calculated for high latitudes in the presence of forcing by solar radiation and magnetospheric convection with a 60 kV cross-tail potential, i.e., conditions on Oct. 21, 1981. It was found that ion drag and pressure forces balance out at F region heights where ion drift velocities are small. The magnetic polar cap/auroral zone boundary featured the largest residual force or net acceleration. Diurnal oscillations were detected in the thermospheric convection, and geostrophic balance was dominant in the E layer.

  15. 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.

  16. Results of two-phase natural circulation in hot-leg U-bend simulation experiments

    SciTech Connect

    Ishii, M.; Lee, S.Y.; Abou El-Seoud, S.

    1987-01-01

    In order to study the two-phase natural circulation and flow termination during a small break loss of coolant accident in LWR, simulation experiments have been performed using two different thermal-hydraulic loops. The main focus of the experiment was the two-phase flow behavior in the hot-leg U-bend typical of BandW LWR systems. The first group of experiments was carried out in the nitrogen gas-water adiabatic simulation loop and the second in the Freon 113 boiling and condensation loop. Both of the loops have been designed as a flow visualization facility and built according to the two-phase flow scaling criteria developed under this program. The nitrogen gas-water system has been used to isolate key hydrodynamic phenomena such as the phase distribution, relative velocity between phases, two-phase flow regimes and flow termination mechanisms, whereas the Freon loop has been used to study the effect of fluid properties, phase changes and coupling between hydrodynamic and heat transfer phenomena. Significantly different behaviors have been observed due to the non-equilibrium phase change phenomena such as the flashing and condensation in the Freon loop. The phenomena created much more unstable hydrodynamic conditions which lead to cyclic or oscillatory flow behaviors.

  17. [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. PMID:16445230

  18. 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)

  19. 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.

  20. 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.

  1. Calculation of unmitigated release from reverse circulation drilling of a borehole three meters south of borehole 41-15-09 near SST 241-SX-115

    SciTech Connect

    SCOTT, D.L.

    1999-05-27

    To more fully characterize the vadose zone near Single Shell Tank 241-SX-115, another borehole will be drilled and sampled by using reverse circulation drilling equipment. Compressed air propels the drill and sweeps out cuttings. Dose calculations in this document are performed for an unmitigated airborne release from the drill string. Doses were found not to exceed TWRS risk guideline values.

  2. 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

  3. 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

  4. 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)

  5. Isolation of naturally occurring Campylobacter from the circulating blood of commercial market age broilers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Campylobacter spp., are present in organs and tissues of broiler chickens but the dissemination route is unclear. The aim of the current study was to determine Campylobacter prevalence within circulating blood of commercial broilers. Broilers were acquired from 19 flocks originating from three com...

  6. 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.

  7. Calculation of the effective dose from natural radioactivity in soil using MCNP code.

    PubMed

    Krstic, D; Nikezic, D

    2010-01-01

    Effective dose delivered by photon emitted from natural radioactivity in soil was calculated in this work. Calculations have been done for the most common natural radionuclides in soil (238)U, (232)Th series and (40)K. A ORNL human phantoms and the Monte Carlo transport code MCNP-4B were employed to calculate the energy deposited in all organs. The effective dose was calculated according to ICRP 74 recommendations. Conversion factors of effective dose per air kerma were determined. Results obtained here were compared with other authors. PMID:20045343

  8. 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.

  9. Natural and anthropogenic radionuclide distributions in the Nansen Basin, Artic Ocean: Scavenging rates and circulation timescales

    NASA Astrophysics Data System (ADS)

    Kirk Cochran, J.; Hirschberg, David J.; Livingston, Hugh D.; Buesseler, Ken O.; Key, Robert M.

    Determination of the naturally occurring radionuclides 232Th, 230Th, 228 Th and 210Pb, and the anthropogenic radionuclides 241Am, 239,240Pu, 134Cs and 137Cs in water samples collected across the Nansen Basin from the Barents Sea slope to the Gakkel Ridge provides tracers with which to characterize both scavenging rates and circulation timescales in this portion of the Arctic Ocean. Large volume water samples (˜ 15001) were filtered in situ to separate particulate (> 0.5 μm) and dissolved Th isotopes and 241Am. Thorium-230 displays increases in both particulate and dissolved activities with depth, with dissolved 230Th greater and particulate 230Th lower in the deep central Nansen Basin than at the Barents Sea slope. Dissolved 228Th activities also are greater relative to 228Ra, in the central basin. Residence times for Th relative to removal from solution onto particles are ˜1 year in surface water, ˜10 years in deep water adjacent to the Barents Sea slope, and ˜20 years in the Eurasian Basin Deep Water. Lead-210 in the central basin deep water also has a residence time of ˜20 years with respect to its removal from the water column. This texture of scavenging is reflected in distributions of the particle-reactive anthropogenic radionuclide 241Am, which shows higher activities relative to Pu in the central Nansen Basin than at the Barents Sea slope. Distributions Of 137Cs show more rapid mixing at the basin margins (Barents Sea slope in the south, Gakkel Ridge in the north) than in the basin interior. Cesium-137 is mixed throughout the water column adjacent to the Barents Sea slope and is present in low but detectable activities in the Eurasian Basin Deep Water in the central basin. At the time of sampling (1987) the surface water at all stations had been labeled with 134Cs released in the 1986 accident at the Chernobyl nuclear power station. In the ˜1 year since the introduction of Chernobyl 134Cs to the Nansen Basin, it had been mixed to depths of ˜800 m at

  10. 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.

  11. Circulating microparticles carry oxidation-specific epitopes and are recognized by natural IgM antibodies1[S

    PubMed Central

    Tsiantoulas, Dimitrios; Perkmann, Thomas; Afonyushkin, Taras; Mangold, Andreas; Prohaska, Thomas A.; Papac-Milicevic, Nikolina; Millischer, Vincent; Bartel, Caroline; Hörkkö, Sohvi; Boulanger, Chantal M.; Tsimikas, Sotirios; Fischer, Michael B.; Witztum, Joseph L.; Lang, Irene M.; Binder, Christoph J.

    2015-01-01

    Oxidation-specific epitopes (OSEs) present on apoptotic cells and oxidized low density lipoprotein (OxLDL) represent danger-associated molecular patterns that are recognized by different arcs of innate immunity, including natural IgM antibodies. Here, we investigated whether circulating microparticles (MPs), which are small membrane vesicles released by apoptotic or activated cells, are physiological carriers of OSEs. OSEs on circulating MPs isolated from healthy donors and patients with ST-segment elevation myocardial infarction (STE-MI) were characterized by flow cytometry using a panel of OSE-specific monoclonal antibodies. We found that a subset of MPs carry OSEs on their surface, predominantly malondialdehyde (MDA) epitopes. Consistent with this, a majority of IgM antibodies bound on the surface of circulating MPs were found to have specificity for MDA-modified LDL. Moreover, we show that MPs can stimulate THP-1 (human acute monocytic leukemia cell line) and human primary monocytes to produce interleukin 8, which can be inhibited by a monoclonal IgM with specificity for MDA epitopes. Finally, we show that MDA+ MPs are elevated at the culprit lesion site of patients with STE-MI. Our results identify a subset of OSE+ MPs that are bound by OxLDL-specific IgM. These findings demonstrate a novel mechanism by which anti-OxLDL IgM antibodies could mediate protective functions in CVD. PMID:25525116

  12. Deficiencies of Circulating Mucosal-associated Invariant T Cells and Natural Killer T Cells in Patients with Acute Cholecystitis.

    PubMed

    Kim, Jung-Chul; Jin, Hye-Mi; Cho, Young-Nan; Kwon, Yong-Soo; Kee, Seung-Jung; Park, Yong-Wook

    2015-05-01

    Mucosal-associated invariant T (MAIT) cells and natural killer T (NKT) cells are known to play crucial roles in a variety of diseases, including autoimmunity, infectious diseases, and cancers. However, little is known about the roles of these invariant T cells in acute cholecystitis. The purposes of this study were to examine the levels of MAIT cells and NKT cells in patients with acute cholecystitis and to investigate potential relationships between clinical parameters and these cell levels. Thirty patients with pathologically proven acute cholecystitis and 47 age- and sex-matched healthy controls were enrolled. Disease grades were classified according to the revised Tokyo guidelines (TG13) for the severity assessment for acute cholecystitis. Levels of MAIT and NKT cells in peripheral blood were measured by flow cytometry. Circulating MAIT and NKT cell numbers were significantly lower in acute cholecystitis patients than in healthy controls, and these deficiencies in MAIT cells and NKT cell numbers were associated with aging in acute cholecystitis patients. Notably, a reduction in NKT cell numbers was found to be associated with severe TG13 grade, death, and high blood urea nitrogen levels. The study shows numerical deficiencies of circulating MAIT and NKT cells and age-related decline of these invariant T cells. In addition, NKT cell deficiency was associated with acute cholecystitis severity and outcome. These findings provide an information regarding the monitoring of these changes in circulating MAIT and NKT cell numbers during the course of acute cholecystitis and predicting prognosis.

  13. 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.

  14. Hand-held calculator programs determine natural-gas physical properties

    SciTech Connect

    Ajitsaria, N.K.

    1983-06-01

    Although physical properties of natural gas are readily available in the literature, the determination of such properties using a hand-held calculator can be of great convenience to the engineer. Two typical examples of gas properties often required in gas transmission and reservoir engineering calculations are compressibility factor (z factor) and viscosity (..mu..). In this article, programs developed for determining these properties are described.

  15. Circulation of Coxiella burnetii in a Naturally Infected Flock of Dairy Sheep: Shedding Dynamics, Environmental Contamination, and Genotype Diversity.

    PubMed

    Joulié, A; Laroucau, K; Bailly, X; Prigent, M; Gasqui, P; Lepetitcolin, E; Blanchard, B; Rousset, E; Sidi-Boumedine, K; Jourdain, E

    2015-10-01

    Q fever is a worldwide zoonosis caused by Coxiella burnetii. Domestic ruminants are considered to be the main reservoir. Sheep, in particular, may frequently cause outbreaks in humans. Because within-flock circulation data are essential to implementing optimal management strategies, we performed a follow-up study of a naturally infected flock of dairy sheep. We aimed to (i) describe C. burnetii shedding dynamics by sampling vaginal mucus, feces, and milk, (ii) assess circulating strain diversity, and (iii) quantify barn environmental contamination. For 8 months, we sampled vaginal mucus and feces every 3 weeks from aborting and nonaborting ewes (n=11 and n=26, respectively); for lactating females, milk was obtained as well. We also sampled vaginal mucus from nine ewe lambs. Dust and air samples were collected every 3 and 6 weeks, respectively. All samples were screened using real-time PCR, and strongly positive samples were further analyzed using quantitative PCR. Vaginal and fecal samples with sufficient bacterial burdens were then genotyped by multiple-locus variable-number tandem-repeat analysis (MLVA) using 17 markers. C. burnetii burdens were higher in vaginal mucus and feces than in milk, and they peaked in the first 3 weeks postabortion or postpartum. Primiparous females and aborting females tended to shed C. burnetii longer and have higher bacterial burdens than nonaborting and multiparous females. Six genotype clusters were identified; they were independent of abortion status, and within-individual genotype diversity was observed. C. burnetii was also detected in air and dust samples. Further studies should determine whether the within-flock circulation dynamics observed here are generalizable.

  16. Geothermal Recovery System Using Natural Circulating CO2 as A Heat Transfer Fluid

    NASA Astrophysics Data System (ADS)

    Soma, Hiroshi; Iwasawa, Kenji; Fukumiya, Kenji

    In the conventional system, heat is recovered as sensible heat through liquid anti-freezer circulating in a piping laid underground, but if CO2 is used as a heat transfer fluid, heat is recovered as latent heat which increases the capacity and enables to promote downsize of the equipment and reduction of the electric consumption. It also enables the diameter or the length of heat recovery piping for the same heat exchange performance, thus the installation cost of the piping would be reduced. In our study, a geothermal recovery system using CO2 for air-conditioning was installed, and the heating capacity and the electric consumption were measured. Also, those of a conventional propylene-glycol system were measured. As a result, the CO2-system exerted the same heating ability with the propylene-glycol system with a half length of heat recovery piping and a half electric consumption of the propylene-glycol system. And the reduction in the diameter of the CO2 recovery piping was possible to 50 mm at most to gain more than adequate heating effect.

  17. Evidence for the circulation of antimicrobial-resistant strains and genes in nature and especially between humans and animals.

    PubMed

    Wooldridge, M

    2012-04-01

    The concern over antibiotic-resistant bacteria producing human infections that are difficult to treat has led to a proliferation of studies in recent years investigating resistance in livestock, food products, the environment and people, as well as in the mechanisms of transfer of the genetic elements of resistance between bacteria, and the routes, or risk pathways, by which the spread of resistance might occur. The possibility of transfer of resistant genetic elements between bacteria in mixed populations adds many additional and complex potential routes of spread. There is now considerable evidence that transfer of antimicrobial resistance from food-producing animals to humans directly via the food chain is a likely route of spread. The application of animal wastes to farmland and subsequent leaching into watercourses has also been shown to lead to many potential, but less well-documented, pathways for spread. Often, however, where contamination of water sources, processed foods, and other environmental sites is concerned, specific routes of circulation are unclear and may well involve human sources of contamination. Examination of water sources in particular may be difficult due to dilution and their natural flow. Also, as meat is comparatively easy to examine, and is frequently suspected of being a source of spread, there is some bias in favour of studying this vehicle. Such complexities mean that, with the evidence currently available, it is not possible to prioritise the importance of potential risk pathways and circulation routes.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Validation of the in-vessel energy balance module in SSC for natural circulation transients. [LMFBR

    SciTech Connect

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

    1982-01-01

    Recently, the in-vessel energy module of the Super System Code (SSC) which calculates the fuel pin, coolant, and stucture temperatures, was changed from an explicit finite difference procedure to an implicit weighted residuals procedure. SSC is a computer code for the analysis of plant wide transients in reactor systems. SSC is designed to be fast running, i.e., faster than real time, while providing detailed information if desired. Therefore, it was necessary to show that the new procedure was computationally efficient, i.e., provide high accuracy and short computational times.

  4. 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.

  5. 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''.

  6. 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

  7. 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.

  8. Uterine and circulating natural killer cells and their roles in women with recurrent pregnancy loss, implantation failure and preeclampsia.

    PubMed

    Fukui, Atsushi; Funamizu, Ayano; Yokota, Megumi; Yamada, Kenichi; Nakamua, Rika; Fukuhara, Rie; Kimura, Hidetaka; Mizunuma, Hideki

    2011-06-01

    The regulation of uterine and circulating peripheral blood natural killer (NK) cells has been associated with reproductive conditions including recurrent pregnancy loss (RPL), implantation failure and preeclampsia. Natural cytotoxicity receptors (NCRs) are unique markers that regulate NK cell cytotoxicity and cytokine production. The role of NCRs in reproductive events has not yet been fully characterized. There is an NK1 (Type 1) shift in peripheral blood NK cells in non-pregnant women prone to RPL and implantation failure. The different profile of NCR expression in endometrial or aborted decidual NK cells suggests the presence of abnormal regulation of NK cells in women with reproductive failure. Women with a history of RPL and preeclampsia carry immunological abnormalities of NCRs on peripheral blood NK cells during pregnancy. Evaluation of NKp46 on peripheral blood NK cells may be applicable for the prediction of preeclampsia. The lower expression of NKp46(+) NK cells in women with preeclampsia may account for the higher production of NK1 cytokines - known as the NK1 shift - in pregnant women with preeclampsia. In this review, the expression of NCRs in peripheral blood NK cells and endometrial or decidual NK cells is discussed in relation to reproductive failure.

  9. Circulating concentrations of soluble granzyme A and B increase during natural and experimental Plasmodium falciparum infections.

    PubMed

    Hermsen, C C; Konijnenberg, Y; Mulder, L; Loé, C; van Deuren, M; van der Meer, J W M; van Mierlo, G J; Eling, W M C; Hack, C E; Sauerwein, R W

    2003-06-01

    Release of soluble Granzymes (sGranzymes) is considered to reflect activation of cytotoxic T lymphocytes and NK cells. sGranzymes and a number of pro-inflammatory cytokines were measured in plasma of malaria patients with natural or experimentally induced Plasmodium falciparum infections. Concentrations of sGranzyme A and B, IL-10, IL-12p70 and CRP were significantly increased in African children presenting with clinical malaria; IL-10 and CRP concentrations were significantly correlated with disease severity. In nonimmune Dutch volunteers which were experimentally infected by P. falciparum-infected mosquitoes, sGranzyme A increment started 1-2 days prior to clinical symptoms and microscopically detectable parasitaemia. This coincided with increases in IFNgamma, IL-12p40 and IL-8, while sGranzyme B and IL-10 levels increased 24-48 h later. The elevation of sGranzyme A and IFNgamma in nonimmune volunteers suggests that NK cells are activated upon release of parasites by infected liver cells and subsequently during blood stage infection; thus, NK cells are likely involved innate immune human host resistance in the early phase of a malaria infection.

  10. Simulation experiments on two-phase natural circulation in a freon-113 flow visualization loop

    SciTech Connect

    Lee, Sang Yong; Ishii, Mamoru

    1988-01-01

    In order to study the two-phase natural circulaton and flow termination during a small break loss of coolant accident in LWR, simulation experiments have been performed using a Freon-113 flow visualization loop. The main focus of the present experiment was placed on the two-phase flow behavior in the hot-leg U-bend typical of B and W LWR systems. The loop was built based on the two-phase flow scaling criteria developed under this program to find out the effect of fluid properties, phase changes and coupling between hydrodynamic and heat transfer phenomena. Significantly different flow behaviors have been observed due to the non-equilibrium phase change phenomena such as the flashing and condensation on the Freon loop in comparison with the previous adiabatic experiment. The phenomena created much more unstable hydrodynamic conditions which lead to cyclic or oscillatory flow behaviors. Also, the void distribution and primary loop flow rate were measured in detail in addition to the important key paramaters, such as the power input, loop friction and the liquid level inside the simulated steam generator.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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...

  18. On the effectiveness of nature-inspired metaheuristic algorithms for performing phase equilibrium thermodynamic calculations.

    PubMed

    Fateen, Seif-Eddeen K; Bonilla-Petriciolet, Adrian

    2014-01-01

    The search for reliable and efficient global optimization algorithms for solving phase stability and phase equilibrium problems in applied thermodynamics is an ongoing area of research. In this study, we evaluated and compared the reliability and efficiency of eight selected nature-inspired metaheuristic algorithms for solving difficult phase stability and phase equilibrium problems. These algorithms are the cuckoo search (CS), intelligent firefly (IFA), bat (BA), artificial bee colony (ABC), MAKHA, a hybrid between monkey algorithm and krill herd algorithm, covariance matrix adaptation evolution strategy (CMAES), magnetic charged system search (MCSS), and bare bones particle swarm optimization (BBPSO). The results clearly showed that CS is the most reliable of all methods as it successfully solved all thermodynamic problems tested in this study. CS proved to be a promising nature-inspired optimization method to perform applied thermodynamic calculations for process design. PMID:24967430

  19. Extended DLVO calculations expose the role of the structural nature of the adsorbent beads during chromatography.

    PubMed

    Aasim, Muhammad; Bibi, Noor Shad; Vennapusa, Rami Reddy; Fernandez-Lahore, Marcelo

    2012-05-01

    Protein adsorption onto hydrophobic interaction chromatography supports was studied by a surface-thermodynamics approach. To gather relevant experimental information, contact angle measurements and zeta potential determinations were performed on three different commercial adsorbent beads, Phenyl Sepharose 6 Fast Flow, Toyopearl Phenyl 650-C and Source 15 Phenyl, having soft to rigid backbone structure. Similar information was obtained for a collection of model proteins, lysozyme, bovine serum albumin (BSA), polygalacturonase, aminopeptidase, chymosin, aspartic protease, beta-galactosidase, human immunoglobulin G, and lactoferrin, were evaluated in the hydrated and in the dehydrated state. Based on the mentioned experimental data, calculations were performed to obtain the (interfacial) energy versus distance profiles of nine individual (model) proteins on (commercial) beads of three different types. All of these beads harbored the phenyl-ligand onto a matrix of differentiated chemical nature. Extended Derjaguin, Landau, Verwey, and Overbeek (DLVO) calculations were correlated with actual chromatographic behavior. Typical chromatography conditions were employed. The population of model proteins utilized in this study could be segregated into two groups, according to the minimum values observed for the resulting interaction energy pockets and the corresponding retention volumes (or times) during chromatography. Moreover, trends were also identified as a function of the type of adsorbent bead under consideration. This has revealed the influence of the physicochemical nature of the bead structure on the adsorption process and consequently, on the expected separation behavior.

  20. Calculation of unmitigated release from reverse circulation drilling of a borehole three meters south of borehole 41-15-09 near SST 241-SX-115

    SciTech Connect

    SCOTT, D.L.

    1999-05-25

    It is known that underground, single shell tank (SST) 241-SX-115 leaked 50,000 gallons of contaminated liquid to the soil. Now there is a campaign to more fully characterize the plume from that leak. To determine radionuclide concentrations in the vadose zone, boring into the soil and collecting samples of it are needed. It was decided to bore a new hole 3 m (9.8 ft) from existing borehole number 41-15-09, located near the south edge of the tank. Drilling and sampling will be done with the use of reverse circulation drilling, which uses compressed air to power the drill bit and sweep out drillings into separation and sampling equipment. Prior to drilling, however, it was determined that safety assessment calculations were needed to find out if postulated releases from the drilling would pose unacceptable risk to onsite and offsite receptors. Unacceptable risk would require the design and construction of safety significant equipment for prevention or mitigation of the release.

  1. Natural Atomic Orbital Representation for Optical Spectra Calculations in the Exciton Scattering Approach.

    PubMed

    Li, Hao; Chernyak, Vladimir Y; Tretiak, Sergei

    2012-12-20

    The exciton scattering (ES) method allows efficient calculations of spectroscopic observables in large low-dimensional conjugated molecular systems. To compute the transition dipoles between the ground and excited electronic states, we should extract the ES dipole parameters from quantum chemistry calculations in simple molecular fragments. In this manuscript, we show how to retrieve these parameters from any reference quantum chemistry model that uses an arbitrary nonorthogonal and possibly overcomplete atomic orbital basis set. Our approach relies on the natural atomic orbital (NAO) representation, in which the basis functions are orthonormal and the atom-like character is preserved. We apply the ES approach, combined with the NAO analysis to optical spectra of branched phenylacetylene oligomers. Absorption spectra predicted by the ES method demonstrate close agreement with the results of direct quantum chemistry calculations, when the Time-Dependent Density Functional Theory (TD-DFT) being used as a reference. This testifies applicability of a variety of quantum-chemical techniques, where the NAO population analysis can be conducted, for the ES framework. PMID:26291103

  2. Natural Atomic Orbital Representation for Optical Spectra Calculations in the Exciton Scattering Approach.

    PubMed

    Li, Hao; Chernyak, Vladimir Y; Tretiak, Sergei

    2012-12-20

    The exciton scattering (ES) method allows efficient calculations of spectroscopic observables in large low-dimensional conjugated molecular systems. To compute the transition dipoles between the ground and excited electronic states, we should extract the ES dipole parameters from quantum chemistry calculations in simple molecular fragments. In this manuscript, we show how to retrieve these parameters from any reference quantum chemistry model that uses an arbitrary nonorthogonal and possibly overcomplete atomic orbital basis set. Our approach relies on the natural atomic orbital (NAO) representation, in which the basis functions are orthonormal and the atom-like character is preserved. We apply the ES approach, combined with the NAO analysis to optical spectra of branched phenylacetylene oligomers. Absorption spectra predicted by the ES method demonstrate close agreement with the results of direct quantum chemistry calculations, when the Time-Dependent Density Functional Theory (TD-DFT) being used as a reference. This testifies applicability of a variety of quantum-chemical techniques, where the NAO population analysis can be conducted, for the ES framework.

  3. Comparison of results between the DEMO 1-D and the COMMIX 3-D analysis of the CRBRP-IHX under a natural-circulation event

    SciTech Connect

    Cheung, A.C.; Kao, T.T.; Cho, S.M.; Lowrie, R.R.

    1983-01-01

    In order to assess the multi-dimensional thermal-hydraulic effects in an intermediate heat thermal-hydraulic effects in an intermediate heat exchanger (IHX) and to ascertain the adequacy of the DEMO one-dimensional (1-D) IHX model in natural circulation analysis, a comparison of the predictions by the DEMO and the COMMIX three-dimensional (3-D) computer code has been conducted. The CRBRP IHX configuration was used in this benchmark comparison. The COMMIX results clearly demonstrated that there is no significant flow channeling or stratification on either the shell or tube side of the CRBRP IHX during the postulated natural circulation event. Comparisons of the integrated thermal heads predicted by the two codes for the CRBRP IHX show differences of .013 and .024 psi (90 and 164 W/m/sup 2/ for both the primary and the secondary side respectively. These results demonstrate that, while a 1-D IHX model can not predict the velocity and temperature distribution inside the IHX in complete detail, it is adequate for the analysis of a heat transport system under design base natural circulation events (i.e. accidents initiated by the simultaneous loss of all AC power during power operation).

  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. 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

    Experimental and theoretical studies were made of the heat transfer characteristics of a latent heat storage unit used for a natural circulation cooling /latent heat storage system. Heating and cooling curves of the latent heat storage unit undergoing solid-liquid phase change of a PCM (lauric acid) was obtained by using anatural circulation loop of R22 which consisted of an electrically heated evaporater, a water cooled condenser and the latent heat storage unit. The latent heat storage unit showed a heat transfer performance which was high enough for practical use. An approximate theoretical analysis was conducted to investigate transient behavior of the latent heat storage unit. Predictions of the refrigerant and outer surface temperatures during the melting process were in fair agreement with the experimental data, whereas that of the refrigerant temperature during the solidification process was considerably lower than the measurement.

  6. 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)

  7. A short-term increase of the postoperative naturally circulating dendritic cells subsets in flurbiprofen-treated patients with esophageal carcinoma undergoing thoracic surgery.

    PubMed

    Wang, Di; Yang, Xin-lu; Chai, Xiao-qing; Shu, Shu-hua; Zhang, Xiao-lin; Xie, Yan-hu; Wei, Xin; Wu, Yu-jing; Wei, Wei

    2016-04-01

    The present study evaluated whether flurbiprofen increased the naturally circulating dendritic cells (DCs) subsets in patients with esophageal squamous cell carcinoma (ESCC) undergoing esophageal resection. Compared to healthy donors (n=20), the significantly depressed percentages of plasmacytoid DCs (pDCs), CD1c+ myeloid DCs (mDCs), and CD141+ mDCs among ESCC patients (n=60) were confirmed. Flurbiprofen was administered before skin incision and at the end of operation in group F (n=30), as well as placebo in group C (n=30). The postoperative suppressed percentages of pDCs, CD1c+ mDCs, and CD141+ mDCs increased significantly following the perioperative treatment with flurbiprofen. Flurbiprofen also significantly stimulated the postoperative IFN-f and IL-17 production, but inhibited the immunosuppressive IL-10 and TGF-β levels. Furthermore, flurbiprofen exerted a similar analgesic effect and brought a significantly less sufentanil consumption compared to group C. Taken together, flurbiprofen provided a short-term increase of postoperative naturally circulating DCs in ESCC patients.

  8. 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.

  9. 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.

  10. A short-term increase of the postoperative naturally circulating dendritic cells subsets in flurbiprofen-treated patients with esophageal carcinoma undergoing thoracic surgery

    PubMed Central

    Chai, Xiao-qing; Shu, Shu-hua; Zhang, Xiao-lin; Xie, Yan-hu; Wei, Xin; Wu, Yu-jing; Wei, Wei

    2016-01-01

    The present study evaluated whether flurbiprofen increased the naturally circulating dendritic cells (DCs) subsets in patients with esophageal squamous cell carcinoma (ESCC) undergoing esophageal resection. Compared to healthy donors (n=20), the significantly depressed percentages of plasmacytoid DCs (pDCs), CD1c+ myeloid DCs (mDCs), and CD141+ mDCs among ESCC patients (n=60) were confirmed. Flurbiprofen was administered before skin incision and at the end of operation in group F (n=30), as well as placebo in group C (n=30). The postoperative suppressed percentages of pDCs, CD1c+ mDCs, and CD141+ mDCs increased significantly following the perioperative treatment with flurbiprofen. Flurbiprofen also significantly stimulated the postoperative IFN-f and IL-17 production, but inhibited the immunosuppressive IL-10 and TGF-β levels. Furthermore, flurbiprofen exerted a similar analgesic effect and brought a significantly less sufentanil consumption compared to group C. Taken together, flurbiprofen provided a short-term increase of postoperative naturally circulating DCs in ESCC patients. PMID:26959879

  11. 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.

  12. Crystal structure and theoretical calculations of Julocrotine, a natural product with antileishmanial activity

    NASA Astrophysics Data System (ADS)

    Moreira, Rafael Y. O.; Brasil, Davi S. B.; Alves, Cláudio N.; Guilhon, Giselle M. S. P.; Santos, Lourivaldo S.; Arruda, Mara S. P.; Müller, Adolfo H.; Barbosa, Patrícia S.; Abreu, Alcicley S.; Silva, Edilene O.; Rumjanek, Victor M.; Souza, Jaime, Jr.; da Silva, Albérico B. F.; Santos, Regina H. De A.

    Julocrotine, N-(2,6-dioxo-1-phenethyl-piperidin-3-yl)-2-methyl-butyramide, is a potent antiproliferative agent against the promastigote and amastigote forms of Leishmania amazonensis (L.). In this work, the crystal structure of Julocrotine was solved by X-ray diffraction, and its geometrical parameters were compared with theoretical calculations at the B3LYP and HF level of theory. IR and NMR spectra also have been obtained and compared with theoretical calculations. IR absorptions calculated with the B3LYP level of theory employed together with the 6-311G+(d,p) basis set, are close to those observed experimentally. Theoretical NMR calculations show little deviation from experimental results. The results show that the theory is in accordance with the experimental data.0

  13. Lung Circulation.

    PubMed

    Suresh, Karthik; Shimoda, Larissa A

    2016-04-01

    The circulation of the lung is unique both in volume and function. For example, it is the only organ with two circulations: the pulmonary circulation, the main function of which is gas exchange, and the bronchial circulation, a systemic vascular supply that provides oxygenated blood to the walls of the conducting airways, pulmonary arteries and veins. The pulmonary circulation accommodates the entire cardiac output, maintaining high blood flow at low intravascular arterial pressure. As compared with the systemic circulation, pulmonary arteries have thinner walls with much less vascular smooth muscle and a relative lack of basal tone. Factors controlling pulmonary blood flow include vascular structure, gravity, mechanical effects of breathing, and the influence of neural and humoral factors. Pulmonary vascular tone is also altered by hypoxia, which causes pulmonary vasoconstriction. If the hypoxic stimulus persists for a prolonged period, contraction is accompanied by remodeling of the vasculature, resulting in pulmonary hypertension. In addition, genetic and environmental factors can also confer susceptibility to development of pulmonary hypertension. Under normal conditions, the endothelium forms a tight barrier, actively regulating interstitial fluid homeostasis. Infection and inflammation compromise normal barrier homeostasis, resulting in increased permeability and edema formation. This article focuses on reviewing the basics of the lung circulation (pulmonary and bronchial), normal development and transition at birth and vasoregulation. Mechanisms contributing to pathological conditions in the pulmonary circulation, in particular when barrier function is disrupted and during development of pulmonary hypertension, will also be discussed. PMID:27065170

  14. Anti-Wolbachia Surface Protein Antibodies Are Present in the Urine of Dogs Naturally Infected with Dirofilaria immitis with Circulating Microfilariae But Not in Dogs with Occult Infections

    PubMed Central

    Morchón, Rodrigo; Carretón, Elena; Grandi, Giulio; González-Miguel, Javier; Montoya-Alonso, J. Alberto; Simón, Fernando; Genchi, Claudio

    2012-01-01

    Abstract Heartworm infection (Dirofilaria immitis) can cause kidney damage due to the presence of circulating microfilariae (mf) that contribute to the production and deposit of immune complexes. It has been shown that mf are a major source of Wolbachia antigen during active infection. Here the authors compared urine samples from 19 naturally infected dogs with (mf+) and 12 without (mf−) microfilariae for the presence of proteinuria and anti-Wolbachia Surface Protein (-WSP) IgG in ELISA. Kidneys from 6 mf+ and 3 mf− dogs were also examined by anti-WSP immuno-histochemistry. All infected dogs showed proteinuria, but mf+ dogs had significantly higher values compared to mf−dogs. Mf+ dogs had optical density values for anti-WSP IgG consistently higher than established cut-off values and were significantly higher than values for mf− dogs. Kidneys from mf+ dogs showed Wolbachia+ mf in glomerular capillaries. Results strongly suggest that Wolbachia associated with circulating mf may contribute to immune-mediated kidney disease in dogs with heartworm infection. PMID:21919732

  15. 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.

  16. 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

  17. Calculating contingencies in natural environments: issues in the application of sequential analysis.

    PubMed

    McComas, Jennifer J; Moore, Timothy; Dahl, Norm; Hartman, Ellie; Hoch, John; Symons, Frank

    2009-01-01

    Analysis and interpretation of behavior-environment relations are increasingly being conducted with data that have been derived descriptively. This paper provides an overview of the logic that underlies a sequential analytic approach to the analysis of descriptive data. Several methods for quantifying sequential relations are reviewed along with their strengths and weaknesses. Data from descriptive analyses are used to illustrate key points. Issues germane to contingency analysis in natural environments are discussed briefly. It is concluded that the conceptual distinctions among contiguity, contingency, and dependency are critical if the logic of sequential analysis is to be extended successfully to a behavior-analytic account of reinforcement in natural environments.

  18. 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...

  19. Calculations of the spectral nature of the microwave emission from soils. [Arizona and Georgia

    NASA Technical Reports Server (NTRS)

    Mo, T.; Schmugge, T. J.; Choudhury, B. J. (Principal Investigator)

    1980-01-01

    The brightness temperatures for a set of soil profiles observed at USDA facilities in Arizona and Georgia were calculated at the wavelengths of 2.8, 6, 11, 21, and 49 cm using a coherent radiative transfer model. The soil moisture sampling depth is found to be a function of wavelength and is in the range 0.06 to 0.1 of a wavelength. The thermal sampling depth also depends on wavelength and is approximately equal to one wavelength at dry soil condition and 0.1 - 0.5 wavelengths at wet soil conditions. Calculated values of emissivity show strong diurnal variations when the soils are wet, while there is little diurnal change when the soil is dry. The soil moistures within the four depth intervals of 0-2, 0-5, 0-9, and 0-15 cm were parameterized as function of the calculated emissivity and brightness temperature. Best-fit parameters and correlation coefficients are presented for five wavelengths. Interrelationships among the effective temperature, surface temperature, and emissivity are displayed.

  20. 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

  1. 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.

  2. 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. PMID:19741358

  3. [Yersinia pestis factors, assuring circulation and maintenance of the plague pathogen in natural foci ecosystems. Report 1].

    PubMed

    Anisimov, A P

    2002-01-01

    Everlasting reproduction of Yersinia pestis, plague bacillus in natural pestholes needs virulent causative agent to invade into the host entity, be potent to overcome protection powers of the rodent organism and to pullulate to entail bacteriemia for subsequent conveyance the plague bacillus to the new host by fleas. All of legs of life cyclic patterns of Yersinia pestis are maintained by a number of plague bacillus factors acting jointly or separately, participating at the different stages of infectious process or conveyance. However these factors provide the perpetuation of the plague bacillus in the ecosystems of natural pestholes only acting in conjunction independently on their distinct contributions. Not only biomolecules, organellas and bacteria systems ensured the pursuance of virulent properties, but other factors, essential for survival of Yersinia pestis and the relationship between separate virulence factors and expression of the different genes of housekeeping and virulence of plague bacillus are considered in this review. The report I covers the problems concerned with adaptational plasticity of Yersinia pestis, it represents the classification of plague causative factors, securing its perpetuation in the environmental space, and discussion the factors promoting plague bacillus survival in the host entity. Not only wellknown publications, but papers in out-of-the-way or hard-to-reach, especially for English-reading experts, editions, also were used to compile this communication. The English version of this review may be requested from Alerton Press. PMID:12243063

  4. Lack of anti-tumour reactivity despite enhanced numbers of circulating natural killer T cells in two patients with metastatic renal cell carcinoma.

    PubMed

    Vyth-Dreese, F A; Sein, J; van de Kasteele, W; Dellemijn, T A M; van den Bogaard, C; Nooijen, W J; de Gast, G C; Haanen, J B A G; Bex, A

    2010-12-01

    Natural killer T (NK T) cells play a central role as intermediates between innate and adaptive immune responses important to induce anti-tumour reactivity in cancer patients. In two of 14 renal cell carcinoma (RCC) patients, treated with interferon (IFN)-α, we detected significantly enhanced numbers of circulating NK T cells which were typed phenotypically and analysed for anti-tumour reactivity. These NK T cells were T cell receptor (TCR) Vα24/Vβ11(+), 6B11(+) and bound CD1d tetramers. No correlation was observed between NK T frequencies and regulatory T cells (T(regs)), which were also enhanced. NK T cells expressed CD56, CD161, CD45RO and CD69 and were predominantly CD8(+), in contrast to the circulating T cell pool that contained both CD4(+) and CD8(+) T cells, as is found in healthy individuals. It is unlikely that IFN-α triggered the high NK T frequency, as all other patients expressed low to normal NK T numbers. A parallel was observed in IFN-α-related increase in activation of NK T cells with that in conventional T and non-T cells. Normal interleukin (IL)-7, IL-12 and IL-15 plasma levels were found. In one of the patients sporadic NK T cells were detected at the tumour site. α-Galactosylceramide (αGalCer) stimulation of peripheral blood mononuclear cells or isolated NK T cell lines from both patients induced IFN-γ, but no IL-4 and no response towards autologous tumour cells or lysates. The clinical course of disease in both patients was not exceptional with regard to histological subtype and extent of metastatic disease. Therefore, despite a constitutive high peripheral frequency and in vitroαGalCer responsiveness, the NK T cells in the two RCC patients did not show anti-tumour responsiveness.

  5. Peripheral circulation.

    PubMed

    Laughlin, M Harold; Davis, Michael J; Secher, Niels H; van Lieshout, Johannes J; Arce-Esquivel, Arturo A; Simmons, Grant H; Bender, Shawn B; Padilla, Jaume; Bache, Robert J; Merkus, Daphne; Duncker, Dirk J

    2012-01-01

    Blood flow (BF) increases with increasing exercise intensity in skeletal, respiratory, and cardiac muscle. In humans during maximal exercise intensities, 85% to 90% of total cardiac output is distributed to skeletal and cardiac muscle. During exercise BF increases modestly and heterogeneously to brain and decreases in gastrointestinal, reproductive, and renal tissues and shows little to no change in skin. If the duration of exercise is sufficient to increase body/core temperature, skin BF is also increased in humans. Because blood pressure changes little during exercise, changes in distribution of BF with incremental exercise result from changes in vascular conductance. These changes in distribution of BF throughout the body contribute to decreases in mixed venous oxygen content, serve to supply adequate oxygen to the active skeletal muscles, and support metabolism of other tissues while maintaining homeostasis. This review discusses the response of the peripheral circulation of humans to acute and chronic dynamic exercise and mechanisms responsible for these responses. This is accomplished in the context of leading the reader on a tour through the peripheral circulation during dynamic exercise. During this tour, we consider what is known about how each vascular bed controls BF during exercise and how these control mechanisms are modified by chronic physical activity/exercise training. The tour ends by comparing responses of the systemic circulation to those of the pulmonary circulation relative to the effects of exercise on the regional distribution of BF and mechanisms responsible for control of resistance/conductance in the systemic and pulmonary circulations.

  6. Absolute structural elucidation of natural products--a focus on quantum-mechanical calculations of solid-state CD spectra.

    PubMed

    Pescitelli, Gennaro; Kurtán, Tibor; Flörke, Ulrich; Krohn, Karsten

    2009-01-01

    In this review article we examine state-of-the-art techniques for the structural elucidation of organic compounds isolated from natural sources. In particular, we focus on the determination of absolute configuration (AC), perhaps the most challenging but inevitable step in the whole process, especially when newly isolated compounds are screened for biological activity. Among the many methods employed for AC assignment that we review, special attention is paid to electronic circular dichroism (CD) and to the modern tools available for quantum-mechanics CD predictions, including TDDFT. In this context, we stress that conformational flexibility often poses a limit to practical CD calculations of solution CD spectra. Many crystalline natural products suitable for X-ray analysis do not contain heavy atoms for a confidential AC assignment by resonant scattering. However, their CD spectra can be recorded in the solid state, for example with the KCl pellet technique, and analyzed possibly by nonempirical means to provide stereochemical information. In particular, solid-state CD spectra can be compared with those calculated with TDDFT or other high-level methods, using the X-ray geometry as input. The solid-state CD/TDDFT approach, described in detail, represents a quick and reliable tool for AC assignment of natural products.

  7. 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.

  8. 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

  9. 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.

  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

    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. PMID:26392159

  11. Helmholtz Energy Equations of State for HFC and Natural Refrigerants and Their Applications to Calculations of Thermodynamic Properties

    NASA Astrophysics Data System (ADS)

    Akasaka, Ryo

    This paper overviews Helmholtz energy equations of state for pure HFC and natural refrigerants. The equations of state consist of the ideal-gas part and the residual part. The ideal-gas part can be calculated from the ideal-gas isobaric heat capacity according to the ideal-gas law, and the residual part is determined empirically by fitting to experimental thermodynamic property data. Polynomial and exponential terms are used to represent the residual part. Some equations have more complex terms for accurate descriptions of critical behavior. Mixture models for applications of the pure-fluid equations of state to refrigerant mixtures are summarized. Until now, two mixture models have been developed for HFC refrigerant mixtures. This paper also discusses calculation methods for the pvT relation, vapor-liquid equilibrium, and critical point using Helmholtz energy equations of state. Few literature discusses the methods in detail, although such information is very precious to make a computer program for calculating thermodynamic properties.

  12. Using Streambed Temperature Time Series to Calculate Natural Changes in Streambed Elevation: the Influence of Rain Events

    NASA Astrophysics Data System (ADS)

    Sebok, E.; Engesgaard, P. K.; Duque, C.

    2014-12-01

    The phase shift and amplitude ratio of the diurnal temperature signal of paired streambed temperature sensors have already been used successfully to calculate vertical groundwater fluxes assuming a constant vertical distance between the sensors. Sedimentation and scouring however, can change the position of temperature sensors relative to the streambed influencing calculated groundwater fluxes. Here we report on a field investigation, where streambed sediment temperature time series were used to; (i) determine the range of natural sedimentation and scour over a two month period, (ii) study the influence of rain events on the calculated streambed elevation. The study was carried out at a field site located along Holtum stream, in Western Denmark. The 3 m wide stream has a sandy streambed, a mean discharge of 200 l/s and a mean depth of 0.3 m. Streambed temperatures were measured at two locations in a straight stream section with a vertical high-resolution Distributed Temperature Sensing (DTS) system installed 0.7 m deep in the streambed. Temperature measurements were taken with 30 min intervals between 16 April and 25 June 2013 and streambed elevation was recorded on 24 May and 17 June 2013. The effective thermal diffusivity (κe ) of streambed sediments was measured on 17 June 2013 by a KD2 Pro SH-1 sensor (Decagon Devices). The phase and amplitude of the diurnal temperature signal of paired sensors were extracted by VFLUX. The κe of streambed sediments was calibrated based on measured streambed elevations and validated by in-situ measurements. The range of potential streambed elevation over the two month period was calculated by assuming; (i) sedimentation, using the calibrated κe for saturated streambed sediments, (ii) scouring, using κe for stream water between the temperature sensors. Under natural conditions, streambed elevation changes by 5-12 cm during the two month period and by 1-3 cm even during base flow conditions, emphasizing the importance of

  13. Estimated uncertainty of calculated liquefied natural gas density from a comparison of NBS and Gaz de France densimeter test facilities

    SciTech Connect

    Siegwarth, J.D.; LaBrecque, J.F.; Roncier, M.; Philippe, R.; Saint-Just, J.

    1982-12-16

    Liquefied natural gas (LNG) densities can be measured directly but are usually determined indirectly in custody transfer measurement by using a density correlation based on temperature and composition measurements. An LNG densimeter test facility at the National Bureau of Standards uses an absolute densimeter based on the Archimedes principle, while a test facility at Gaz de France uses a correlation method based on measurement of composition and density. A comparison between these two test facilities using a portable version of the absolute densimeter provides an experimental estimate of the uncertainty of the indirect method of density measurement for the first time, on a large (32 L) sample. The two test facilities agree for pure methane to within about 0.02%. For the LNG-like mixtures consisting of methane, ethane, propane, and nitrogen with the methane concentrations always higher than 86%, the calculated density is within 0.25% of the directly measured density 95% of the time.

  14. 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.

  15. Path sampling calculation of methane diffusivity in natural gas hydrates from a water-vacancy assisted mechanism.

    PubMed

    Peters, Baron; Zimmermann, Nils E R; Beckham, Gregg T; Tester, Jefferson W; Trout, Bernhardt L

    2008-12-24

    Increased interest in natural gas hydrate formation and decomposition, coupled with experimental difficulties in diffusion measurements, makes estimating transport properties in hydrates an important technological challenge. This research uses an equilibrium path sampling method for free energy calculations [Radhakrishnan, R.; Schlick, T. J. Chem. Phys. 2004, 121, 2436] with reactive flux and kinetic Monte Carlo simulations to estimate the methane diffusivity within a structure I gas hydrate crystal. The calculations support a water-vacancy assisted diffusion mechanism where methane hops from an occupied "donor" cage to an adjacent "acceptor" cage. For pathways between cages that are separated by five-membered water rings, the free energy landscape has a high barrier with a shallow well at the top. For pathways between cages that are separated by six-membered water rings, the free energy calculations show a lower barrier with no stable intermediate. Reactive flux simulations confirm that many reactive trajectories become trapped in the shallow intermediate at the top of the barrier leading to a small transmission coefficient for these paths. Stable intermediate configurations are identified as doubly occupied off-pathway cages and methane occupying the position of a water vacancy. Rate constants are computed and used to simulate self-diffusion with a kinetic Monte Carlo algorithm. Self-diffusion rates were much slower than the Einstein estimate because of lattice connectivity and methane's preference for large cages over small cages. Specifically, the fastest pathways for methane hopping are arranged in parallel (nonintersecting) channels, so methane must hop via a slow pathway to escape the channel. From a computational perspective, this paper demonstrates that equilibrium path sampling can compute free energies for a broader class of coordinates than umbrella sampling with molecular dynamics. From a technological perspective, this paper provides one estimate for

  16. Structural determination of complex natural products by quantum mechanical calculations of (13)C NMR chemical shifts: development of a parameterized protocol for terpenes.

    PubMed

    de Albuquerque, Ana Carolina Ferreira; Ribeiro, Daniel Joras; de Amorim, Mauro Barbosa

    2016-08-01

    Nuclear magnetic resonance (NMR) spectroscopy is one of the most important tools for determining the structures of organic molecules. Despite the advances made in this technique, revisions of erroneously established structures for natural products are still commonly published in the literature. In this context, the prediction of chemical shifts through ab initio and density functional theory (DFT) calculations has become a very powerful tool for assisting with the structural determination of complex organic molecules. In this work, we present the development of a protocol for (13)C chemical shift calculations of terpenes, a class of natural products that are widely distributed among plant species and are very important due to their biological and pharmacological activities. This protocol consists of GIAO-DFT calculations of chemical shifts and the application of a parameterized scaling factor in order to ensure accurate structural determination of this class of natural products. The application of this protocol to a set of five terpenes yielded accurate calculated chemical shifts, showing that this is a very attractive tool for the calculation of complex organic structures such as terpenes. PMID:27424297

  17. Corticosteroid-binding globulin reactive centre loop antibodies recognise only the intact natured protein: elastase cleaved and uncleaved CBG may coexist in circulation.

    PubMed

    Lewis, John G; Elder, Peter A

    2011-11-01

    Corticosteroid-binding globulin (CBG) is the principal carrier of cortisol in circulation and is a non-inhibitory member of the serpin family of serine proteinase inhibitors. It possesses an exposed elastase specific site which, when cleaved, allows a conformational change promoting the delivery of cortisol to sites of inflammation. Previously there was no ability to independently distinguish between the uncleaved, stressed, conformer of CBG and total CBG in circulation. Here we raised and characterized monoclonal antibodies generated against a synthetic peptide spanning the elastase cleavage site within the exposed reactive centre loop (RCL) and measured changes in CBG by ELISA following treatment with human neutrophil elastase. The antibodies recognized the synthetic peptide as well as intact CBG and the epitope (STGVTLNL) spanned the elastase cleavage site. Treatment of plasma with elastase resulted in a complete loss of CBG levels determined using these RCL antibodies whereas CBG levels measured with an unrelated CBG monoclonal antibody were unaffected. We also compared plasma levels of CBG measured by RCL antibodies and an unrelated CBG antibody and showed discordance in some samples. This study shows for the first time the ability to measure the intact, stressed conformer of CBG. We report discordance with total CBG in some samples implying the presence of cleaved CBG in circulation. This is an important finding as it has implications for free cortisol which hitherto have been determined from total cortisol and total CBG levels. This antibody could be used for determining the time course of intact CBG in various relevant patient cohorts and for structure/function studies on the biology of human CBG.

  18. Lower numbers of circulating Natural Killer T (NK T) cells in individuals with human T lymphotropic virus type 1 (HTLV-1) associated neurological disease.

    PubMed

    Ndhlovu, L C; Snyder-Cappione, J E; Carvalho, K I; Leal, F E; Loo, C P; Bruno, F R; Jha, A R; Devita, D; Hasenkrug, A M; Barbosa, H M R; Segurado, A C; Nixon, D F; Murphy, E L; Kallas, E G

    2009-12-01

    Human T lymphotropic virus type 1 (HTLV-1) infects 10-20 million people worldwide. The majority of infected individuals are asymptomatic; however, approximately 3% develop the debilitating neurological disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). There is also currently no cure, vaccine or effective therapy for HTLV-1 infection, and the mechanisms for progression to HAM/TSP remain unclear. NK T cells are an immunoregulatory T cell subset whose frequencies and effector functions are associated critically with immunity against infectious diseases. We hypothesized that NK T cells are associated with HAM/TSP progression. We measured NK T cell frequencies and absolute numbers in individuals with HAM/TSP infection from two cohorts on two continents: São Paulo, Brazil and San Francisco, CA, USA, and found significantly lower levels when compared with healthy subjects and/or asymptomatic carriers. Also, the circulating NK T cell compartment in HAM/TSP subjects is comprised of significantly more CD4(+) and fewer CD8(+) cells than healthy controls. These findings suggest that lower numbers of circulating NK T cells and enrichment of the CD4(+) NK T subset are associated with HTLV-1 disease progression.

  19. 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…

  20. 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

  1. On the nature of lithium biphenyl in ethereal solvents. A critical analysis unifying DFT calculations, physicochemical data in solution, and a X-ray structure.

    PubMed

    de la Viuda, Mónica; Yus, Miguel; Guijarro, Albert

    2011-12-15

    The lithium ion is an important type of electrolyte that has technological applications in the manufacture of lithium ion cells; therefore, a better understanding of the nature of its solutions is desirable. When associated to the radical anion of biphenyl in an organic solvent, it forms conducting solutions comparable to strong electrolytes such as lithium perchlorate. We have studied the lithium biphenyl solution in dimethoxyethane using DFT calculations. The nature of these ionic solutions is described in terms of a dynamic equilibrium between different types of ionic associations, the composition of which depends on the solvent and the temperature. The X-ray structure of [Li(+)·4C(5)H(10)O][C(12)H(10)(•-)], a solvent-separated ion pair of lithium biphenyl complexed with tetrahydropyran, is reported. Its main structural characteristics coincide with the calculated one, which we think is the dominant species at room temperature, in agreement with the available physicochemical data.

  2. Strong-field absorption and emission of radiation in two-electron systems calculated with time-dependent natural orbitals

    NASA Astrophysics Data System (ADS)

    Brics, M.; Rapp, J.; Bauer, D.

    2016-01-01

    Recently introduced time-dependent renormalized-natural-orbital theory (TDRNOT) is based on the equations of motion for the so-called natural orbitals, i.e., the eigenfunctions of the one-body reduced density matrix. Exact TDRNOT can be formulated for any time-dependent two-electron system in either spin configuration. In this paper, the method is tested against high-order-harmonic generation (HHG) and Fano profiles in absorption spectra with the help of a numerically exactly solvable one-dimensional-model He atom, starting from the spin-singlet ground state. Such benchmarks are challenging because Fano profiles originate from transitions involving autoionizing states, and HHG is a strong-field phenomenon well beyond the linear response. TDRNOT with just one natural orbital per spin in the helium spin-singlet case is equivalent to time-dependent Hartree-Fock or time-dependent density functional theory (TDDFT) in the exact exchange-only approximation. It is not unexpected that TDDFT fails in reproducing Fano profiles due to the lack of doubly excited, autoionizing states. HHG spectra, on the other hand, are widely believed to be well captured by TDDFT. However, HHG spectra of helium may display a second plateau that originates from simultaneous HHG in +He and neutral He. It is found that TDRNOT with two natural orbitals per spin is already sufficient to capture this effect as well as the Fano profiles on a qualitative level. With more natural orbitals (6-8 per spin), quantitative agreement can be reached. Errors due to the truncation to a finite number of orbitals are identified.

  3. 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.

  4. 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

  5. Natural Circulation in the Blanket Heat Removal System During a Loss-of-Pumping Accident (LOFA) Based on Initial Conceptual Design

    SciTech Connect

    Hamm, L.L.

    1998-10-07

    A transient natural convection model of the APT blanket primary heat removal (HR) system was developed to demonstrate that the blanket could be cooled for a sufficient period of time for long term cooling to be established following a loss-of-flow accident (LOFA). The particular case of interest in this report is a complete loss-of-pumping accident. For the accident scenario in which pumps are lost in both the target and blanket HR systems, natural convection provides effective cooling of the blanket for approximately 68 hours, and, if only the blanket HR systems are involved, natural convection is effective for approximately 210 hours. The heat sink for both of these accident scenarios is the assumed stagnant fluid and metal on the secondary sides of the heat exchangers.

  6. WATEQF; a FORTRAN IV version of WATEQ : a computer program for calculating chemical equilibrium of natural waters

    USGS Publications Warehouse

    Plummer, L. Niel; Jones, Blair F.; Truesdell, Alfred Hemingway

    1976-01-01

    WATEQF is a FORTRAN IV computer program that models the thermodynamic speciation of inorganic ions and complex species in solution for a given water analysis. The original version (WATEQ) was written in 1973 by A. H. Truesdell and B. F. Jones in Programming Language/one (PL/1.) With but a few exceptions, the thermochemical data, speciation, coefficients, and general calculation procedure of WATEQF is identical to the PL/1 version. This report notes the differences between WATEQF and WATEQ, demonstrates how to set up the input data to execute WATEQF, provides a test case for comparison, and makes available a listing of WATEQF. (Woodard-USGS)

  7. 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

  8. 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.

  9. A heat exchanger between forced flow helium gas at 14 to 18 K andliquid hydrogen at 20 K circulated by natural convection

    SciTech Connect

    Green, M.A.; Ishimoto, S.; Lau, W.; Yang, S.

    2003-09-15

    The Muon Ionization Cooling Experiment (MICE) has three 350-mm long liquid hydrogen absorbers to reduce the momentum of 200 MeV muons in all directions. The muons are then re-accelerated in the longitudinal direction by 200 MHz RF cavities. The result is cooled muons with a reduced emittance. The energy from the muons is taken up by the liquid hydrogen in the absorber. The hydrogen in the MICE absorbers is cooled by natural convection to the walls of the absorber that are in turn cooled by helium gas that enters at 14 K. This report describes the MICE liquid hydrogen absorber and the heat exchanger between the liquid hydrogen and the helium gas that flows through passages in the absorber wall.

  10. Assessment of RELAP5/MOD2 against a pressurizer spray valve inadverted fully opening transient and recovery by natural circulation in Jose Cabrera Nuclear Station

    SciTech Connect

    Arroyo, R.; Rebollo, L.

    1993-06-01

    This document presents the comparison between the simulation results and the plant measurements of a real event that took place in JOSE CABRERA nuclear power plant in August 30th, 1984. The event was originated by the total, continuous and inadverted opening of the pressurizer spray valve PCV-400A. JOSE CABRERA power plant is a single loop Westinghouse PWR belonging to UNION ELECTRICA FENOSA, S.A. (UNION FENOSA), an Spanish utility which participates in the International Code Assessment and Applications Program (ICAP) as a member of UNIDAD ELECTRICA, S.A. (UNESA). This is the second of its two contributions to the Program: the first one was an application case and this is an assessment one. The simulation has been performed using the RELAP5/MOD2 cycle 36.04 code, running on a CDC CYBER 180/830 computer under NOS 2.5 operating system. The main phenomena have been calculated correctly and some conclusions about the 3D characteristics of the condensation due to the spray and its simulation with a 1D tool have been got.

  11. Apparatus Circulates Sterilizing Gas

    NASA Technical Reports Server (NTRS)

    Cross, John H.; Schwarz, Ray P.

    1991-01-01

    Apparatus circulates sterilizing gas containing ethylene oxide and chlorofluorocarbon through laboratory or medical equipment. Confines sterilizing gas, circulating it only through parts to be treated. Consists of two units. One delivers ethylene oxide/chlorofluorocarbon gas mixture and removes gas after treatment. Other warms, humidifies, and circulates gas through equipment to be treated. Process provides reliable sterilization with negligible residual toxicity from ethylene oxide. Particularly suitable for sterilization of interiors of bioreactors, heart/lung machines, dialyzers, or other equipment including complicated tubing.

  12. A single acute dose of pinitol from a naturally-occurring food ingredient decreases hyperglycaemia and circulating insulin levels in healthy subjects.

    PubMed

    Hernández-Mijares, Antonio; Bañuls, Celia; Peris, Jose E; Monzó, Nuria; Jover, Ana; Bellod, Lorena; Victor, Victor M; Rocha, Milagros

    2013-11-15

    A limited amount of research suggests that oral ingestion of pinitol (3-O-methyl-d-chiro-inositol) positively influences glucose tolerance in humans. This study assessed the effects of different doses of pinitol supplementation on glucose tolerance, insulin sensitivity and plasma pinitol concentrations. Thirty healthy subjects underwent two one-day trials in which they consumed a nutritive beverage (Fruit Up®) containing 2.5, 4.0 or 6.0g of pinitol and a corresponding placebo equivalent in both energy and carbohydrates. Blood samples were collected frequently over the 240-min test period. The pinitol-enriched beverage reduced serum glucose and insulin at 45 and 60min, but only at a dose of 6.0g. Plasma pinitol concentrations, maximum concentration and AUC increased according to the dose administered. The results show that a single dose of pinitol from a naturally-occurring food ingredient at the highest dose administered acutely influences indices of whole-body glucose tolerance and insulin sensitivity in healthy subjects.

  13. Midlatitudes precipitation and the global atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Pauluis, O.; Czaja, A.; Korty, R.; Laliberte, F.

    2008-12-01

    The global atmospheric circulation transports energy from the equatorial regions to higher latitudes. Due to the turbulent nature of the flow, describing a 'mean' circulation depends strongly on the averaging method and coordinates system. When averaged in isentropic coordinates, the circulation appears as a single overturning cell with a poleward flow of high entropy air and return flow at lower entropy. However, the entropy of a parcel of moist air is not uniquely defined, and different expression for the entropy yield different mean circulations. Here, the global circulation in the NCEP/NCAR Reanalysis is computed on surfaces of constant potential temperature, or dry isentropes, and on surfaces of constant equivalent potential temperature, or moist isentropes. The two analyses are qualitatively similar but differ quantitatively in that the circulation on moist isentropes is between 1.5 and 3 times larger than the circulation on dry isentropes. It is shown that the additional mass transport on moist isentropes corresponds to a poleward flow of warm, moist air near the Earth's surface that moves from the subtropics into the midlatitudes and rises in the upper troposphere within the stormtracks. In the subtropics, this flow is characterized by a low potential temperature but a much higher equivalent potential temperature. It does not appear in the circulation on dry isentropes, as it is hidden by the presence of a larger equatorward flow of drier air at same potential temperature. However, as the equivalent potential temperature in this low-level poleward flow is close to the potential temperature of the air near the tropopause, it is included in the total circulation on moist isentropes. The thermodynamic properties of this low-level poleward flow indicates that these poleward moving air parcels should ascend into the upper troposphere within the midlatitude stormtracks. Based on these findings, we propose a revised version of the global circulation. We argue that

  14. Projection space image reconstruction using strip functions to calculate pixels more "natural" for modeling the geometric response of the SPECT collimator.

    PubMed

    Hsieh, Y L; Zeng, G L; Gullberg, G T

    1998-02-01

    The spatially varying geometric response of the collimator-detector system in single photon emission computed tomography (SPECT) causes loss in resolution, shape distortions, reconstructed density nonuniformity, and quantitative inaccuracies. A projection space image reconstruction algorithm is used to correct these reconstruction artifacts. The projectors F use strip functions to calculate pixels more "natural" for modeling the two-dimensional (2-D) geometric response of the SPECT collimator transaxially to the axis of rotation. These projectors are defined by summing the intersection of an array of multiple strips rotated at equal angles to approximate the ideal system geometric response of the collimator. Two projection models were evaluated for modeling the system geometric response function. For one projector each strip is of equal weight, for the other projector a Gaussian weighting is used. Parallel beam and fan beam projections of a physical three-dimensional (3-D) Hoffman brain phantom and a Jaszczak cold rod phantom were used to evaluate the geometric response correction. Reconstructions were obtained by using the singular value decomposition (SVD) method and the iterative conjugate gradient algorithm to solve for q in the imaging equation FGq = p, where p is the projection measurement. The projector F included the new models for the geometric response, whereas, the backprojector G did not always model the geometric response in order to increase the computational speed. The final reconstruction was obtained by sampling the backprojection Gq at a discrete array of points. Reconstructions produced by the two proposed projectors showed improved resolution when compared against a unit-strip "natural" pixel model, the conventional image pixelized model with ray tracing to calculate the geometric response, and the filtered backprojection algorithm. When the reconstruction is displayed on fine grid points, the continuity and resolution of the image is preserved

  15. 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.

  16. 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.

  17. Hall Effect Gyrators and Circulators

    NASA Astrophysics Data System (ADS)

    Viola, Giovanni; DiVincenzo, David P.

    2014-04-01

    The electronic circulator and its close relative the gyrator are invaluable tools for noise management and signal routing in the current generation of low-temperature microwave systems for the implementation of new quantum technologies. The current implementation of these devices using the Faraday effect is satisfactory but requires a bulky structure whose physical dimension is close to the microwave wavelength employed. The Hall effect is an alternative nonreciprocal effect that can also be used to produce desired device functionality. We review earlier efforts to use an Ohmically contacted four-terminal Hall bar, explaining why this approach leads to unacceptably high device loss. We find that capacitive coupling to such a Hall conductor has much greater promise for achieving good circulator and gyrator functionality. We formulate a classical Ohm-Hall analysis for calculating the properties of such a device, and show how this classical theory simplifies remarkably in the limiting case of the Hall angle approaching 90°. In this limit, we find that either a four-terminal or a three-terminal capacitive device can give excellent circulator behavior, with device dimensions far smaller than the ac wavelength. An experiment is proposed to achieve GHz-band gyration in millimeter (and smaller) scale structures employing either semiconductor heterostructure or graphene Hall conductors. An inductively coupled scheme for realizing a Hall gyrator is also analyzed.

  18. Spectroscopic investigation, natural bond orbital analysis, HOMO-LUMO and thermodynamic functions of 2-tert-butyl-5-methyl anisole using DFT (B3LYP) calculations.

    PubMed

    Balachandran, V; Santhi, G; Karpagam, V; Revathi, B; Karabacak, M

    2015-02-01

    The optimized molecular structure and corresponding vibrational assignments of 2-tert-butyl-5-methyl anisole (TBMA) have been investigated using density functional theory (DFT)/B3LYP with 6-31G(d,p) and 6-311++G(d,p) basis sets investigation of the relative orientation of the methoxy group has shown two conformers (O-cis) and (O-trans) exist. The vibrational analysis of the stable conformer of the title compound is performed by means of infrared absorption and Raman spectroscopy in combination with theoretical simultaneously. The natural bond orbital (NBO) analysis is useful to understand the intra-molecular hyper conjugative interaction lone pair and π(∗)(C-C), σ(∗)(C-H) bond orbital. HOMO and LUMO energies show that charge transfer occurs in the molecule, therefore; HOMO, LUMO and molecular electrostatic potential (MEP) were calculated and analyzed. (1)H and (13)C NMR spectra by using gauge including atomic orbital (GIAO) method of studied compound were compared with experimental data. The thermodynamic functions of TBMA were calculated by B3LYP/6-311+G(d,p) basis set.

  19. 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.

  20. Mountains and Tropical Circulation

    NASA Astrophysics Data System (ADS)

    Naiman, Z.; Goodman, P. J.; Krasting, J. P.; Malyshev, S.; Russell, J. L.; Stouffer, R. J.

    2015-12-01

    Observed tropical convection exhibits zonal asymmetries that strongly influence spatial precipitation patterns. The drivers of changes to this zonally-asymmetric Walker circulation on decadal and longer timescales have been the focus of significant recent research. Here we use two state-of-the-art earth system models to explore the impact of earth's mountains on the Walker circulation. When all land-surface topography is removed, the Walker circulation weakens by 33-59%. There is a ~30% decrease in global, large-scale upward vertical wind velocities in the middle of the troposphere, but only minor changes in global average convective mass flux, precipitation, surface and sea-surface temperatures. The zonally symmetric Hadley circulation is also largely unchanged. Following the spatial pattern of changes to large-scale vertical wind velocities, precipitation becomes less focused over the tropics. The weakening of the Walker circulation, but not the Hadley circulation, is similar to the behavior of climate models during radiative forcing experiments: in our simulations, the weakening is associated with changes in vertical wind velocities, rather than the hydrologic cycle. These results indicate suggest that mountain heights may significantly influence the Walker circulation on geologic time scales, and observed changes in tropical precipitation over millions of years may have been forced by changes in tropical orography.

  1. Venus atmospheric circulation - Observations and implications of the thermal structure

    NASA Technical Reports Server (NTRS)

    Limaye, S. S.

    1985-01-01

    Thermal structure data obtained by Pioneer Venus (PV) were analyzed and used to make calculations concerning cyclostrophic circulation around Venus. These indicate a balanced zonal (east to west) circulation, with midlatitude jets of peak velocities in the 110-120 m/s range, located between 50 and 40 mb in each hemisphere of the planet near 45 deg latitude. The calculations indicate breakdown of the balance conditions near the upper and lower boundaries at low latitudes. A slight asymmetry in the balanced zonal circulation arises out of an asymmetry in the thermal field. The PV radio occultation data show evidence of a direct meridional circulation that may be important in sustaining the atmospheric circulation of Venus. The value of continuous radio occultation measurements is stressed for studying shortand long-term variations of the atmospheric circulation.

  2. 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. PMID:16041566

  3. 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)

  4. Atmospheric Circulation and Dynamics

    NASA Astrophysics Data System (ADS)

    Limaye, Sanjay S.; Rengel, Miriam

    The deep atmosphere of Venus ( ˜ 180 km including the thermosphere) presents both observational and modeling challenges. Its thick, nearly uniform global cloud cover makes it difficult to fathom the vertical structure of the global circulation through available techniques that are applied to Earth's atmosphere. Further, the slow rotation of the planet and the consequential prevailing cyclostrophic balance restricts easy inferences about the meridional flow and circulation (Gierasch et al. 1997, Read 1986, Schubert et al. 2007).

  5. 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.

  6. Persistent changes in circulating and intestinal γδ T cell subsets, invariant natural killer T cells and mucosal-associated invariant T cells in children and adults with coeliac disease.

    PubMed

    Dunne, Margaret R; Elliott, Louise; Hussey, Seamus; Mahmud, Nasir; Kelly, Jacinta; Doherty, Derek G; Feighery, Conleth F

    2013-01-01

    Coeliac disease is a chronic small intestinal immune-mediated enteropathy precipitated by exposure to dietary gluten in genetically predisposed individuals. The only current therapy is a lifelong gluten free diet. While much work has focused on the gliadin-specific adaptive immune response in coeliac disease, little is understood about the involvement of the innate immune system. Here we used multi-colour flow cytometry to determine the number and frequency of γδ T cells (Vδ1, Vδ2 and Vδ3 subsets), natural killer cells, CD56(+) T cells, invariant NKT cells, and mucosal associated invariant T cells, in blood and duodenum from adults and children with coeliac disease and healthy matched controls. All circulating innate lymphocyte populations were significantly decreased in adult, but not paediatric coeliac donors, when compared with healthy controls. Within the normal small intestine, we noted that Vδ3 cells were the most abundant γδ T cell type in the adult epithelium and lamina propria, and in the paediatric lamina propria. In contrast, patients with coeliac disease showed skewing toward a predominant Vδ1 profile, observed for both adult and paediatric coeliac disease cohorts, particularly within the gut epithelium. This was concurrent with decreases in all other gut lymphocyte subsets, suggesting a specific involvement of Vδ1 cells in coeliac disease pathogenesis. Further analysis showed that γδ T cells isolated from the coeliac gut display an activated, effector memory phenotype, and retain the ability to rapidly respond to in vitro stimulation. A profound loss of CD56 expression in all lymphocyte populations was noted in the coeliac gut. These findings demonstrate a sustained aberrant innate lymphocyte profile in coeliac disease patients of all ages, persisting even after elimination of gluten from the diet. This may lead to impaired immunity, and could potentially account for the increased incidence of autoimmune co-morbidity. PMID:24124528

  7. Persistent changes in circulating and intestinal γδ T cell subsets, invariant natural killer T cells and mucosal-associated invariant T cells in children and adults with coeliac disease.

    PubMed

    Dunne, Margaret R; Elliott, Louise; Hussey, Seamus; Mahmud, Nasir; Kelly, Jacinta; Doherty, Derek G; Feighery, Conleth F

    2013-01-01

    Coeliac disease is a chronic small intestinal immune-mediated enteropathy precipitated by exposure to dietary gluten in genetically predisposed individuals. The only current therapy is a lifelong gluten free diet. While much work has focused on the gliadin-specific adaptive immune response in coeliac disease, little is understood about the involvement of the innate immune system. Here we used multi-colour flow cytometry to determine the number and frequency of γδ T cells (Vδ1, Vδ2 and Vδ3 subsets), natural killer cells, CD56(+) T cells, invariant NKT cells, and mucosal associated invariant T cells, in blood and duodenum from adults and children with coeliac disease and healthy matched controls. All circulating innate lymphocyte populations were significantly decreased in adult, but not paediatric coeliac donors, when compared with healthy controls. Within the normal small intestine, we noted that Vδ3 cells were the most abundant γδ T cell type in the adult epithelium and lamina propria, and in the paediatric lamina propria. In contrast, patients with coeliac disease showed skewing toward a predominant Vδ1 profile, observed for both adult and paediatric coeliac disease cohorts, particularly within the gut epithelium. This was concurrent with decreases in all other gut lymphocyte subsets, suggesting a specific involvement of Vδ1 cells in coeliac disease pathogenesis. Further analysis showed that γδ T cells isolated from the coeliac gut display an activated, effector memory phenotype, and retain the ability to rapidly respond to in vitro stimulation. A profound loss of CD56 expression in all lymphocyte populations was noted in the coeliac gut. These findings demonstrate a sustained aberrant innate lymphocyte profile in coeliac disease patients of all ages, persisting even after elimination of gluten from the diet. This may lead to impaired immunity, and could potentially account for the increased incidence of autoimmune co-morbidity.

  8. Ocean circulation and climate change

    NASA Astrophysics Data System (ADS)

    Hasselmann, Klaus

    1991-09-01

    Recent numerical simulations using global ocean circulation models are reviewed together with model experiments involving further important climate sub-systems with which the ocean interacts: the atmosphere, the air-sea interface and the global carbon cycle. A common feature of all ocean circulation experiments considered is the strong sensitivity of the circulation to relatively minor changes in surface forcing, particularly to the buoyancy fluxes in regions of deep water formation in high latitudes. This may explain some of the well-known deficiencies of past global ocean circulation simulations. The strong sensitivity may also have been the cause of rapid climate changes observed in paleoclimatic records and can lead further to significant natural climate variability on the time scales of a few hundred years through the stochastic forcing of the ocean by atmospheric weather variability. Gobal warming computations using two different coupled ocean-atmosphere models for the "business-as-usual" scenario of the Intergovernmental Panel on Climate Change yield a significantly stronger warming delay due to the heat uptake by the oceans in the Southern Ocean than estimated on the basis of box-diffusion models. Recent advances in surface wave modelling, illustrated by a comparison of wave height fields derived from the WAM model and the GEOSAT altimeter, hold promise for the development of an improved representation of ocean-atmosphere coupling based on an explicit description of the dynamical processes at the air-sea interface. Global carbon cycle simulations with a three dimensional carbon cycle model tuned to reproduce past variations of carbon cycle indices show a significant impact of variations in the ocean circulation on the CO2 concentration in the atmosphere and thereby on climate. The series of experiments suggest that for the study of climate in the time scale range from 10-Ocean circulation and climate change

    NASA Astrophysics Data System (ADS)

    Hasselmann, Klaus

    1991-08-01

    Recent numerical simulations using global ocean circulation models are reviewed together with model experiments involving further important climate sub-systems with which the ocean interacts: the atmosphere, the air-sea interface and the global carbon cycle. A common feature of all ocean circulation experiments considered is the strong sensitivity of the circulation to relatively minor changes in surface forcing, particularly to the buoyancy fluxes in regions of deep water formation in high latitudes. This may explain some of the well-known deficiencies of past global ocean circulation simulations. The strong sensitivity may also have been the cause of rapid climate changes observed in paleoclimatic records and can lead further to significant natural climate variability on the time scales of a few hundred years through the stochastic forcing of the ocean by atmospheric weather variability. Gobal warming computations using two different coupled ocean-atmosphere models for the "business-as-usual" scenario of the Intergovernmental Panel on Climate Change yield a significantly stronger warming delay due to the heat uptake by the oceans in the Southern Ocean than estimated on the basis of box-diffusion models. Recent advances in surface wave modelling, illustrated by a comparison of wave height fields derived from the WAM model and the GEOSAT altimeter, hold promise for the development of an improved representation of ocean-atmosphere coupling based on an explicit description of the dynamical processes at the air-sea interface. Global carbon cycle simulations with a three dimensional carbon cycle model tuned to reproduce past variations of carbon cycle indices show a significant impact of variations in the ocean circulation on the CO2 concentration in the atmosphere and thereby on climate. The series of experiments suggest that for the study of climate in the time scale range from 10-Nature of Zr-monosubstituted monomeric and dimeric polyoxometalates in water solution at different pH conditions: static density functional theory calculations and dynamic simulations.

    PubMed

    Jiménez-Lozano, Pablo; Carbó, Jorge J; Chaumont, Alain; Poblet, Josep M; Rodríguez-Fortea, Antonio; Wipff, Georges

    2014-01-21

    Static density functional theory (DFT) calculations with a continuous solvent model as well as classical and Car-Parrinello molecular dynamics (MD) simulations with explicit solvent molecules were performed to study the nature of Zr-monosubstituted monomeric and dimeric polyoxometalates (POMs) in water at different pHs. We have analyzed Zr-aqua, -hydroxo, and -aqua-hydroxo species derived from Linqvist- and Keggin-type anions. Both DFT and Car-Parrinello MD methods suggest that the Zr center tends to have coordination number greater than 6 and can bind up to 3 water molecules. Car-Parrinello MD simulations also show that the Zr atom fluctuates within the oxide POM framework, providing a flexible coordination environment. There is a small thermodynamic preference for the Zr-aqua species over the protonated Zr-hydroxo species; however the prevalence of one or the other species might depend on the pH. Classical MD simulations show that H3O(+) interacts mainly with hydroxo ligand, while OH(-) anions prefer the protons of the H2O ligands. In general, an increase of the acidity favors the formation of Zr-aqua species, explaining why dimer dissociation is promoted at low pH. At basic conditions Zr-hydroxo species are generated, providing the reactive groups to form Zr···Zr linkages. PMID:24364825

  9. 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.

  10. 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. PMID:26347536

  11. 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

  12. Circulation and Finding System.

    ERIC Educational Resources Information Center

    Pierce, A. R.

    This report describes an online minicomputer-based system, one combining library inventory control with catalog access, that was implemented at Virginia Tech's main library in order to meet the demands of increased circulation activity and rising staff costs. Following overviews of the institutional environment, the systems development department,…

  13. 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.

  14. Circulation Aide Training Manual.

    ERIC Educational Resources Information Center

    Bergeson, Alan O.

    This training manual provides instruction on shelving and other duties for student assistants in the learning resources center at the College of Dupage, located in Illinois. It is noted that prospective student circulation aides are required to read the manual and pass a written test on policies and procedures before they are allowed to shelve…

  15. 40 CFR 230.23 - Current patterns and water circulation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Potential Impacts on Physical and Chemical Characteristics of the Aquatic Ecosystem § 230.23 Current... water in the aquatic ecosystem. Currents and circulation respond to natural forces as modified by...

  16. Pseudo Random Classification of Circulation Patterns - Comparison to Deliberate Methods

    NASA Astrophysics Data System (ADS)

    Philipp, Andreas

    2010-05-01

    Classification of circulations patterns, e.g. of sea level pressure patterns, can be done by many different methods, e.g. by cluster analysis, methods based on eigenvalues or those based on the leader algorithm like the Lund classification. However none of these methods can give clear advice on the problem of appropriate numbers of classes and even though the number is decided different methods lead to different results. High efforts are made to find methods leading to indisbutable results. However, doubts on the classifiability of tropospheric circulation states have been raised recently and the existence of natural groups of similar patterns within the circulation data, which might be caused by circulation regimes, are questionable. If those groups or clusters exist, methods which are designed to find them, in particular cluster analysis, should be superior to classification schemes based on pseudo random definition of classes. In order to prove this assumption, a classification method called "random centroids" has been designed, for each class choosing one single circulation pattern using a random number generator and assigning all remaining patterns to them according to the minimum Euclidean distance. Evaluation metrics like the "explained cluster variance" for pressure, temperature and precipitation are calculated in order to compare those pseudo random classifications to classifications provided by the cost733cat dataset including many different classification catalogs for various methods (COST Action 733 "Harmonisation and Applications of Weather Type Classifications for European regions"). By running the randomcent method 1000 times the empirical probability density function of the evaluation metrics can be established and provides information about the probability for the established deliberate methods to be better than random classifications. The results show that most of the classifications fail to succeed the 95th percentile of the empirical probability

  17. 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.

  18. 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.

  1. Circulating Tumor Cells.

    PubMed

    Paoletti, Costanza; Hayes, Daniel F

    2016-01-01

    Circulating Tumor Cells (CTC) are shed from primary or secondary tumors. Prior studies have demonstrated that enumeration of CTC is a robust independent prognostic factor of progression free and overall survival in patients with early and metastatic breast cancer. CTC, as well as other circulating tumor markers, have the appealing advantages over tissue biopsy of (1) ease of collection, (2) serial evaluation, and (3) interrogation of the entire tumor burden instead of just a limited part of the tumor. Advances have been recently made in phenotyping and genotyping of CTC, which should provide insights into the predictive role of CTC for sensitivity or resistance to therapies. In addition, CTC phenotypic marker changes during the course of treatment may serve as pharmacodynamic monitoring tools. Therefore, CTC may be considered "liquid biopsies," providing prognostic and predictive clinical information as well as additional understanding of tumor heterogeneity.

  2. 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.

  3. Migration and circulation in Ecuador.

    PubMed

    Brea, J A

    1991-01-01

    "This study investigates labor mobility in Ecuador as a function of the socioeconomic structure of places and personal attributes of migrants and circulators (short-term movers).... Particular attention is given to the role of agrarian change in altering established migration and circulation patterns." The author finds that "circulation may significantly alter family organization and the role of women in many Ecuadorian communities."

  4. Library Circulation Systems: An Overview

    ERIC Educational Resources Information Center

    Surace, Cecily J.

    1972-01-01

    The model circulation system outlined is an on-line real time system in which the circulation file is created from the shelf list. The model extends beyond the operational limits of most existing circulation systems and can be considered a reflection of the current state of the art. (36 references) (Author/NH)

  5. Code System to Calculate Fluid Circulation Patterns Near Jets.

    2002-01-18

    Version 00 Distribution is restricted to the United States Only. ORSMAC predicts the temperatures occurring in the immediate vicinity (the near field) of a hot water discharge from a power plant. ORSMAC numerically solves the differential equations governing the conservation of mass, momentum, and energy in a two-dimensional vertical plane containing the power plant discharge. The model allows arbitrary discharge angle and can accommodate either quiescent or cross-flowing ambient conditions.

  6. 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.

  7. 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.

  8. 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. PMID:24992989

  9. 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.

  10. Modelled Circulation In Storfjorden

    NASA Astrophysics Data System (ADS)

    Skogseth, R.; Asplin, L.

    The model area Storfjorden is situated between the islands Spitsbergen, Barentsöya and Edgeöya at the Svalbard Archipelago. The entrance of Storfjorden is defined by a shallow bank Storfjordbanken and some small islands Tusenöyane in southeast, and by an 115m deep sill at about 76 45' N in the south. Maximum depth in Storfjorden is 190m, which is surrounded by gradually shallower shelves in the north, the east and southeast. A steep bottom slope is present on the western side of Storfjorden. He- leysundet and Freemansundet, two sounds between respectively Spitsbergen and Bar- entsöya, and Barentsöya and Edgeöya, define two narrow and shallow entrances in the north and northeast connecting Storfjorden with the northwestern Barents Sea. Strong tidal currents exist in Heleysundet (4-5ms-1) and Freemansundet (2-3ms-1), but the general circulation in Storfjorden is not well known. The coastal current in Storfjor- den is cyclonic directed into Storfjorden south of Edgeöya from the East Spitsbergen Current and out of Storfjorden south of Spitsbergen where it is called Sørkappstrøm- men. A three-dimensional sigma layered numerical ocean model called Bergen Ocean Model (BOM) was used to simulate the circulation in Storfjorden with Freemansundet opened. Two simulations were carried out, one with heat flux (100 Wm-2) and one without heat flux from the ocean to the atmosphere. The heat flux was applied only in the proper fjord area north of the sill and not outside as a crude approximation of the effects of a polynya in the sea ice cover during winter. Both simulations had a 4km horizontal resolution and 21 sigma layers. The model is forced by winds (from the NCEP reanalyzed fields) and tides. Initial fields are from the DNMI/IMR climatol- ogy. The model simulation without heat flux gave a circulation heavily dependent on tidal forcing, showing strong tidal currents up to 2ms-1 in Freemansundet, between Tusenöyane and on Storfjordbanken southwest of Edgeöya. Earlier

  11. 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.

  12. Computer simulation of the mechanically-assisted failing canine circulation.

    PubMed

    Barnea, O; Moore, T W; Jaron, D

    1990-01-01

    A model of the cardiovascular system is presented. The model includes representations of the left and right ventricles, a nonlinear multielement model of the aorta and its main branches, and lumped models of the systemic veins and the pulmonary circulation. A simulation of the intra-aortic balloon pump and representations of physiological compensatory mechanisms are also incorporated in the model. Parameters of the left ventricular model were set to simulate either the normal or failing canine circulation. Pressure and flow waveforms throughout the circulation as well as ventricular pressure and volume were calculated for the normal, failing, and assisted failing circulation. Cardiac oxygen supply and consumption were calculated from the model. They were used as direct indices of cardiac energy supply and utilization to assess the effects of cardiac assistance.

  13. 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.

  14. North Atlantic Circulation

    NASA Astrophysics Data System (ADS)

    Molinari, R.; Bryan, K.; Schott, F.

    The intensity of the North Atlantic winddriven and thermohaline circulation and the close proximity of many oceanographic installations make the North Atlantic a particularly favored region of the world ocean from the standpoint of research in ocean circulation. Recent increases in available data and advances in numerical modeling techniques served as the impetus to convene a joint workshop of modelers and observers working on the North Atlantic with the Scientific Committee on Oceanic Research (SCOR) Working Group (WG) 68 (“North Atlantic Circulation”). Goals of the workshop were to provide an update on data sets and models and to discuss the poleward heat flux problem and possible monitoring strategies. The joint Workshop/SCOR WG-68 meeting was convened by F. Schott (chairman of the working group; Rosenstiel School of Marine and Atmospheric Science, Miami, Fla.), K. Bryan (National Oceanic and Atmospheric Administration/ Geophysical Fluid Dynamics Laboratory (NOAA/GFDL)), and R. Molinari (NOAA/Atlantic Oceanographic and Meteorological Laboratory (NOAA/AOML)).

  15. 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.

  16. Hemorheology and circulation.

    PubMed

    Marossy, A; Svorc, P; Kron, I; Gresová, S

    2009-01-01

    The main functions of the blood are the transport, and delivery of oxygen and nutrients, removal of carbon dioxide and waste products of metabolism, distribution of heat and signals of immune system. They are provided by circulation due to the driving force of the heart. Circulation of the blood depends on its rheological properties of the blood as well as on characteristics of the vessels through which the blood passes. The blood flow resistance is influenced by the complicated architecture of the vascular network and flow behaviour of blood components - blood cells and plasma. The obtained data based on analysis of influences on blood flow are differentiated in the dependence on place and level of investigation. At a macroscopic level the blood appears to be a liquid material, but at a microscopic level the blood appears to be a material with microscopic solid particles of varying size - various blood cells. From this point of view, we have to consider the blood flow in large vessels, and also on the level of microvessels. This division of facts of hemorheology is somewhat simplistic, but is very useful from the point of view of explanation and comprehension. PMID:19628890

  17. 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

  18. Circulation control STOL aircraft design aspects

    NASA Technical Reports Server (NTRS)

    Loth, John L.

    1987-01-01

    Since Davidson patented Circulation Control Airfoils in 1960, there have been only 2 aircraft designed and flown with circulation control (CC). Designing with CC is complex for the following reasons: the relation between lift increase and blowing momentum is nonlinear; for good cruise performance one must change the wing geometry in flight from a round to a sharp trailing edge. The bleed air from the propulsion engines or an auxiliary compressor, must be used efficiently. In designing with CC, the propulsion and control aspects are just as important as aerodynamics. These design aspects were examined and linearized equations are presented in order to facilitate a preliminary analysis of the performance potential of CC. The thrust and lift requirements for takeoff make the calculated runway length very sensitive to the bleed air ratio. Thrust vectoring improves performance and can offset nose down pitching moments. The choice of blowing jet to free stream velocity ratio determines the efficiency of applying bleed air power.

  19. Anatomy of diaphragmatic circulation.

    PubMed

    Comtois, A; Gorczyca, W; Grassino, A

    1987-01-01

    The diaphragmatic circulation was studied in 48 mongrel dogs weighing 10-35 kg by injecting acrylic coloring into the arteries and veins of the diaphragm. The phrenic arteries and internal mammary arteries were found to anastomose head to head, forming an internal arterial circle around the medial leaflet of the diaphragm tendon. This arterial circle emitted vascular branches that traveled between muscle fibers toward the periphery of the diaphragm. These branches anastomosed with vessels of the intercostal arteries to form costophrenic arcades all along the fibers of the crural and costal diaphragms. The intercostal arteries were anastomosed to one another by small vessels within the muscular diaphragm, thus forming an arterial ring around the insertions of the diaphragm on the ribs. The venous drainage has an anatomic distribution similar to that observed on the arterial side, but with the additional presence of valves that could play a role in directing blood flow.

  20. Hallaran's circulating swing.

    PubMed

    Breathnach, Caoimhghin S

    2010-03-01

    William Saunders Hallaran (c.1765-1825) was physician superintendent at the County and City of Cork Lunatic Asylum for 40 years, where he distinguished between mental insanity and organic (systemic) delirium. In treatment he used emetics and purgatives, digitalis and opium, the shower bath and exercise, and argued that patients should be saved from 'unavoidable sloth' by mental as well as manual occupation. However, it is as an exponent of the circulating swing, proposed by Erasmus Darwin and used by Joseph Cox, that he is remembered. His best results were achieved, as he recorded in An Enquiry in 1810, by inducing sleep in mania of recent onset, but perhaps his most enduring observation was that some of his patients enjoyed the rotatory experience, and he had enough sense to allow the use of the swing as a mode of amusement.

  1. 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.

  2. 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.

  3. 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

  4. Climate modelling: Northern Hemisphere circulation.

    PubMed

    Gillett, Nathan P

    2005-09-22

    Air pressure at sea level during winter has decreased over the Arctic and increased in the Northern Hemisphere subtropics in recent decades, a change that has been associated with 50% of the Eurasian winter warming observed over the past 30 years, with 60% of the rainfall increase in Scotland and with 60% of the rainfall decrease in Spain. This trend is inconsistent with the simulated response to greenhouse-gas and sulphate-aerosol changes, but it has been proposed that other climate influences--such as ozone depletion--could account for the discrepancy. Here I compare observed Northern Hemisphere sea-level pressure trends with those simulated in response to all the major human and natural climate influences in nine state-of-the-art coupled climate models over the past 50 years. I find that these models all underestimate the circulation trend. This inconsistency suggests that we cannot yet simulate changes in this important property of the climate system or accurately predict regional climate changes.

  5. 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.

  6. MEMS Calculator

    National Institute of Standards and Technology Data Gateway

    SRD 166 MEMS Calculator (Web, free access)   This MEMS Calculator determines the following thin film properties from data taken with an optical interferometer or comparable instrument: a) residual strain from fixed-fixed beams, b) strain gradient from cantilevers, c) step heights or thicknesses from step-height test structures, and d) in-plane lengths or deflections. Then, residual stress and stress gradient calculations can be made after an optical vibrometer or comparable instrument is used to obtain Young's modulus from resonating cantilevers or fixed-fixed beams. In addition, wafer bond strength is determined from micro-chevron test structures using a material test machine.

  7. Chaotic Calculations.

    ERIC Educational Resources Information Center

    Chenery, Gordon

    1991-01-01

    Uses chaos theory to investigate the nonlinear phenomenon of population growth fluctuation. Illustrates the use of computers and computer programs to make calculations in a nonlinear difference equation system. (MDH)

  8. 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

  9. 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

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

    PubMed

    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.

  11. 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

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

    PubMed

    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

  13. 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.

  14. Virtual extracorporeal circulation process.

    PubMed

    Boschetti, F; Montevecchi, F M; Fumero, R

    1997-06-01

    Virtual instruments for an extracorporeal circulation (ECC) process were developed to simulate the reactions of a patient to different artificial perfusion conditions. The computer simulation of the patient takes into account the hydraulic, volume, thermal and biochemical phenomena and their interaction with the devices involved in ECC (cannulae dimensions, oxygenator and filter types, pulsatile or continuous pump and thermal exchangers). On the basis of the patient's initialisation data (height, weight, Ht) and perfusion variables (pump flow rate, water temperature, gas flow rate and composition) imposed by the operator, the virtual ECC monitors simulated arterial and venous pressure tracings in real time, along with arterial and venous flow rate tracings, urine production tracing and temperature levels. Oxyhemoglobin arterial and venous blood saturation together with other related variables (pO2, pCO2, pH, HCO3 are also monitored. A drug model which allows the simulation of the effect of vasodilator and diuretic drugs is also implemented. Alarms are provided in order to check which variables (pressure, saturation, pH, urine flow) are out of the expected ranges during the ECC simulation. Consequently the possibility of modifying the control parameters of the virtual devices of the ECC in run-time mode offers an interaction mode between the operator and the virtual environment. PMID:9259211

  15. 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.

  16. Impact of boundary regions on the interior circulation of the California Current System in a regional modeling framework

    NASA Astrophysics Data System (ADS)

    Veneziani, M.; Edwards, C.; Moore, A.

    2008-12-01

    We use the Regional Ocean Modeling System (ROMS) to model the circulation of the California Current System (CCS) using ECCO-GODAE products to force the model at the open boundaries of the domain. We investigate the impact that lateral boundary forcing (and the boundary region in general) has on particular metrics of the interior circulation by adopting both an adjoint model and a traditional sensitivity approach. Adjoint methods are naturally suited to sensitivity studies as they provide the direct dependencies of circulation metrics on uncertainties of the model initial conditions, surface and lateral external forcing, and model parameters, but their results are only valid within the time scale during which the linearity assumption underlying adjoint models can be considered to hold. More traditional sensitivity studies must be conducted to investigate longer time scales. We describe the adjoint model results for two metrics that represent the upwelling processes of the Central California region and the mean sea level field of the coastal circulation, respectively. The spatial distribution of the adjoint sensitivity fields allows us to quantify the contribution of the boundary regions over a biweekly time scale. We investigate longer time scales by adopting two methods: 1) apply different ECCO products at the open boundaries and evaluate mean stratification changes in the CalCOFI coastal region; 2) release passive tracers at the boundaries and calculate ventilation time scales and pathways from the boundary areas to the CCS interior.

  17. 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. PMID:27524865

  18. 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.

  19. 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

  20. 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

  1. [Cancer stemness and circulating tumor cells].

    PubMed

    Saito, Tomoko; Mimori, Koshi

    2015-05-01

    The principle concept of cancer stem cells (CSCs) giving rise to the carcinogenesis, relapse or metastasis of malignancy is broadly recognized. On the other hand, circulating tumor cells (CTCs) also plays important roles in relapse or metastasis of malignancy, and there has been much focused on the association between CSCs and CTCs in cancer cases. The technical innovations for detection of CTCs enabled us to unveil the nature of CTCs. We now realize that CTCs isolated by cell surface antibodies, such as DCLK1, LGR5 indicated CSC properties, and CTCs with epitherial-mesenchymal transition(EMT) phenotype showed characteristics of CSCs. PMID:25985635

  2. Shaping Meridional Circulation in Solar and Stellar Convection Zones

    NASA Astrophysics Data System (ADS)

    Featherstone, N. A.; Miesch, M. S.

    2014-12-01

    Meridional circulations play a crucial role in mediating the angular momentum transport within stellar convection zones and, likely, in determining the nature and timing of their dynamos. The length of the solar cycle, for instance, is thought to depend intimately on the transport of magnetic fields by the meridional circulations in the convection zone. We present a series of 3-D nonlinear simulations of solar-like convection, carried out using the Anelastic Spherical Harmonic (ASH) code that are designed to provide insight into those processes responsible for driving and shaping the meridional circulations established within stellar convection zones. These 3-D models have been constructed in such a way as to span the transition between regimes of solar-like differential rotation (fast equator, slow poles) and regimes of so-called ``anti-solar'' differential rotation (slow equator, fast poles). Solar-like states of differential rotation are characterized by multiple cells of meridional circulation in depth at low latitudes, whereas anti-solar states of differential rotation are characterized by a single cell of circulation within each hemisphere. We demonstrate that the transition from single-celled to multi-celled meridional circulation profiles in these two different regimes is directly linked to a change in the nature of the convective Reynolds stress. These results suggest that if convection in the Sun is strongly rotationally-constrained, a multi-cellular meridional circulation profile may well be expected. Transitional regimes do exist, however, and we conclude by examining a simulation wherein convection that is only marginally rotationally constrained can drive both mono-cellular meridional circulation and solar-like differential rotation.

  3. LLNL Ocean General Circulation Model

    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.

  4. 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.

  5. 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.

  6. Correlations between the modelled potato crop yield and the general atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Sepp, Mait; Saue, Triin

    2012-07-01

    Biology-related indicators do not usually depend on just one meteorological element but on a combination of several weather indicators. One way to establish such integral indicators is to classify the general atmospheric circulation into a small number of circulation types. The aim of present study is to analyse connections between general atmospheric circulation and potato crop yield in Estonia. Meteorologically possible yield (MPY), calculated by the model POMOD, is used to characterise potato crop yield. Data of three meteorological stations and the biological parameters of two potato sorts were applied to the model, and 73 different classifications of atmospheric circulation from catalogue 1.2 of COST 733, domain 05 are used to qualify circulation conditions. Correlation analysis showed that there is at least one circulation type in each of the classifications with at least one statistically significant (99%) correlation with potato crop yield, whether in Kuressaare, Tallinn or Tartu. However, no classifications with circulation types correlating with MPY in all three stations at the same time were revealed. Circulation types inducing a decrease in the potato crop yield are more clearly represented. Clear differences occurred between the observed geographical locations as well as between the seasons: derived from the number of significant circulation types, summer and Kuressaare stand out. Of potato varieties, late 'Anti' is more influenced by circulation. Analysis of MSLP maps of circulation types revealed that the seaside stations (Tallinn, Kuressaare) suffer from negative effects of anti-cyclonic conditions (drought), while Tartu suffers from the cyclonic activity (excessive water).

  7. WBGT Calculator

    SciTech Connect

    Hunter, Charles H.

    2000-05-22

    This software calculates a Wet Bulb Globe Temperature (WBGT) using standard measurements from a meteorological station. WBGT is used by Industrial Hygenists (IH) to determine heat stress potential to outdoor workers. Through the mid 1990''s, SRS technicians were dispatched several times daily to measure WBGT with a custom hand held instrument and results were dessiminated via telephone. Due to workforce reductions, the WSRC IH Department asked for the development of an automated method to simulate the WBGT measurement using existing real time data from the Atmospheric Technologies Group''s meteorological monitoring network.

  8. WBGT Calculator

    2000-05-22

    This software calculates a Wet Bulb Globe Temperature (WBGT) using standard measurements from a meteorological station. WBGT is used by Industrial Hygenists (IH) to determine heat stress potential to outdoor workers. Through the mid 1990''s, SRS technicians were dispatched several times daily to measure WBGT with a custom hand held instrument and results were dessiminated via telephone. Due to workforce reductions, the WSRC IH Department asked for the development of an automated method to simulatemore » the WBGT measurement using existing real time data from the Atmospheric Technologies Group''s meteorological monitoring network.« less

  9. Characterization of quantum circulant networks having perfect state transfer

    NASA Astrophysics Data System (ADS)

    Bašić, Milan

    2013-01-01

    In this paper we answer the question of when circulant quantum spin networks with nearest-neighbor couplings can give perfect state transfer. The network is described by a circulant graph G, which is characterized by its circulant adjacency matrix A. Formally, we say that there exists a perfect state transfer (PST) between vertices {a,bin V(G)} if | F( τ) ab | = 1, for some positive real number τ, where F( t) = exp(i At). Saxena et al. (Int J Quantum Inf 5:417-430, 2007) proved that | F( τ) aa | = 1 for some {ain V(G)} and {tauin {R}^+} if and only if all eigenvalues of G are integer (that is, the graph is integral). The integral circulant graph ICG n ( D) has the vertex set Z n = {0, 1, 2, . . . , n - 1} and vertices a and b are adjacent if {gcd(a-b,n)in D} , where {D subseteq {d : d mid n, 1 ≤ d < n}} . These graphs are highly symmetric and have important applications in chemical graph theory. We show that ICG n ( D) has PST if and only if {nin 4{N}} and {D=widetilde{D_3} \\cup D_2\\cup 2D_2\\cup 4D_2|cup {n/2^a}} , where {widetilde{D_3}={din D | n/din 8{N}}, D_2= {din D | n/din 8{N}+4}{setminus}{n/4}} and {ain{1,2}} . We have thus answered the question of complete characterization of perfect state transfer in integral circulant graphs raised in Angeles-Canul et al. (Quantum Inf Comput 10(3&4):0325-0342, 2010). Furthermore, we also calculate perfect quantum communication distance (distance between vertices where PST occurs) and describe the spectra of integral circulant graphs having PST. We conclude by giving a closed form expression calculating the number of integral circulant graphs of a given order having PST.

  10. Periodicity in Academic Library Circulation: A Spectral Analysis.

    ERIC Educational Resources Information Center

    McGrath, William E.

    1996-01-01

    Discussion of the cyclic nature of library use focuses on the use of spectral analysis to identify periods in library circulation series and pickup for shelving at the State University of New York at Buffalo. The theoretical context of time and frequency domains is presented. (Author/LRW)

  11. Equatorial zonal circulations: Historical perspectives

    NASA Astrophysics Data System (ADS)

    Hastenrath, Stefan

    2007-04-01

    The changing perceptions on zonal circulations in the equatorial belt are traced for (a) stratospheric wind regimes, and (b) vertical-zonal circulation cells in the troposphere. (a) Observations from the Krakatoa eruption 1883 and Berson's 1908 expedition to East Africa, along with later soundings over Batavia (Jakarta) led to the notion of "Krakatoa easterlies" around 30 km (10 mb) and "Berson westerlies" around 20 km (50 mb). Prompted by contrary observations since the late 1950s, this dogma was replaced by the notion of easterlies alternating with westerlies in the equatorial stratosphere at a rhythm of about 26 months. (b) Stimulated by Bjerknes' postulate of a "Walker circulation" along the Pacific Equator, a multitude of such cells have been hypothesized at other longitudes, in part from zonal contrasts of temperature and cloudiness. Essential for the diagnosis of equatorial zonal circulation cells is the continuity following the flow between the centers of ascending and subsiding motion. Evaluation of the recent NCEP-NCAR and ECMWF Reanalysis upper-air datasets reveals equatorial zonal circulation cells over the Pacific all year round, over the Atlantic only in boreal winter, and over the Indian Ocean only in autumn, all being seasons and oceanic longitudes with strong zonal flow in the lower troposphere.

  12. 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.

  13. A Distributed Water Circulation Model Incorporating Large Irrigation Schemes for Paddy Areas

    NASA Astrophysics Data System (ADS)

    Yoshida, T.; Masumoto, T.; Kudo, R.; Horikawa, N.

    2010-12-01

    Water intake for paddy irrigation in Japan accounts for approximately 70% of total intake. Spatial and temporal variation of precipitation and river flow changes, likely to be caused by climate changes, directly affect paddy irrigation and its management schemes. Previous studies show that potential water stresses were estimated in the framework of grid-based distributed water circulation models, in which water availability and demand were roughly compared in large-scale grids of 10~100km. However, in mid and small-scale basins, where we carry out impact assessment studies of 1~10km grids, we need schemes to couple the irrigation intake and its allocation, because agricultural water is highly dependent on human decision making processes. Then, we have developed a model that couples natural hydrological behaviors of a basin and artificial irrigation systems. A distributed water circulation model, which explains natural hydrological behaviors of a basin, consists of approximately 1km square gridded meshes. Infiltration and saturation-excess flow and water requirements of irrigated paddy fields on any grid are calculated. The generated surface flow is routed by a kinematic wave equation so that daily flow rate can be calculated at any point of interest. The core of the model is water allocation and management scheme that exploit the spatial database of irrigation facilities and beneficiary areas. This analysis consists of new modeled plane for irrigation, which is calculated independently from the surface plain of the distributed water circulation model. Following the configuration of the water allocation and management schemes, the model is coupled with the distributed water circulation model. The reservoir operation scheme is an algorithm to determine the reservoir releases for irrigation based on requirement and flow rate at downstream diversion weirs. Diversion weirs intake water from associated rivers at the maximum rate, if water is available. The integrated

  14. [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.

  15. 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.

  16. Winds influence Bering Shelf circulation

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2012-05-01

    Circulation over the Bering Sea shelf and between the shelf and the adjacent deep basin affects the ecosystem through nutrient exchange, egg and larvae dispersal, and changes in temperature and salinity. Using numerical models and observations, Danielson et al. present a new simple framework showing how circulation on the Bering shelf varies with wind forcing. They f n d two primary modes of wind forcing, and changes in wind direction tend to reverse the flow around the shelf. Northwesterly winds, which are more common, promote off-shelf transport along the majority of the continental slope, while southeasterly winds, which are less frequent, are associated with greater on-shelf transport. The study improves overall understanding of the Bering shelf circulation. (Geophysical Research Letters, doi:10.1029/2012GL051231, 2012)

  17. [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. PMID:26298813

  18. 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…

  19. Detection of circulating tumor cells.

    PubMed

    de Wit, Sanne; van Dalum, Guus; 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.

  20. 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

  1. Handheld calculator program simplifies calculation of data for gas mixtures

    SciTech Connect

    Karger, W.

    1982-01-11

    For natural gases having several components, Elliott Co.'s handheld calculator program can characterize the gas mixture with a printout that provides its molecular weight, molar specific heat at constant pressure, pseudocritical pressure and temperature, ratio of specific heats, and adiabatic compression exponent. The program also provides for further calculations that yield specific gravity, specific heat/lb, and compressibility.

  2. 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.

  3. 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.

  4. 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…

  5. Automated Circulation. SPEC Kit 43.

    ERIC Educational Resources Information Center

    Association of Research Libraries, Washington, DC. Office of Management Studies.

    Of the 64 libraries responding to a 1978 Association of Research Libraries (ARL) survey, 37 indicated that they used automated circulation systems; half of these were commercial systems, and most were batch-process or combination batch process and online. Nearly all libraries without automated systems cited lack of funding as the reason for not…

  6. Circulating TGFβ in Marfan's Syndrome

    PubMed Central

    Matt, Peter; Schoenhoff, Florian; Habashi, Jennifer; Holm, Tammy; Van Erp, Christel; Loch, David; Carlson, Olga D.; Griswold, Benjamin F.; Fu, Qin; De Backer, Julie; Loeys, Bart; Huso, David; McDonnell, Nazli B.; Van Eyk, Jennifer E.; Dietz, Harry C.

    2009-01-01

    Background Marfan syndrome (MFS) is caused by mutations in the fibrillin-1 gene and dysregulation of transforming growth factor β (TGFβ). Recent evidence suggests that losartan, an AT1 blocker that blunts TGFβ activation, may be an effective treatment for MFS. We hypothesized that dysregulation of TGFβ might be mirrored in circulating TGFβ concentrations. Methods and Results Serum obtained from MFS mutant mice (Fbn1C1039G/+) treated with losartan was analyzed for circulating TGFβ1 concentrations, and compared to those from placebo treated and wild-type mice. Aortic root size was measured by echocardiography. Data was validated in patients with MFS and healthy individuals. In mice, circulating total TGFβ1 concentrations increased with age and were elevated in older untreated Fbn1C1039G/+ mice compared to wild-type mice (P=0.01; n=16, mean±SEM 115±8 ng/ml vs. n=17, 92±4 ng/ml). Losartan-treated Fbn1C1039G/+ mice had lower total TGFβ1 concentrations compared to age-matched Fbn1C1039G/+ mice treated with placebo (P=0.01; n=18, 90±5 ng/ml), and circulating total TGFβ1 levels were indistinguishable from those of age-matched wild-type mice (P=0.8). Correlation was observed between circulating TGFβ1 levels and aortic root diameters in Fbn1C1039G/+ and wild-type mice (P=0.002). In humans, circulating total TGFβ1 concentrations were elevated in patients with MFS compared to control individuals (P<0.0001; n=53, 15±1.7 ng/ml vs. n=74, 2.5±0.4 ng/ml). MFS patients treated with losartan (n=55) or β-blocker (n=80) showed significantly lower total TGFβ1 concentrations compared to untreated Marfans (P≤0.05). Conclusions Circulating TGFβ1 concentrations are elevated in MFS, decrease after administration of losartan and/or β-blocker therapy, and therefore might serve as prognostic and therapeutic marker in MFS. PMID:19635970

  7. 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. PMID:27224209

  8. Circulating Tumor Cells Measurements in Hepatocellular Carcinoma

    PubMed Central

    Chiappini, Franck

    2012-01-01

    Liver cancer is the fifth most common cancer in men and the seventh in women. During the past 20 years, the incidence of HCC has tripled while the 5-year survival rate has remained below 12%. The presence of circulating tumor cells (CTC) reflects the aggressiveness nature of a tumor. Many attempts have been made to develop assays that reliably detect and enumerate the CTC during the development of the HCC. In this case, the challenges are (1) there are few markers specific to the HCC (tumor cells versus nontumor cells) and (2) they can be used to quantify the number of CTC in the bloodstream. Another technical challenge consists of finding few CTC mixed with million leukocytes and billion erythrocytes. CTC detection and identification can be used to estimate prognosis and may serve as an early marker to assess antitumor activity of treatment. CTC can also be used to predict progression-free survival and overall survival. CTC are an interesting source of biological information in order to understand dissemination, drug resistance, and treatment-induced cell death. Our aim is to review and analyze the different new methods existing to detect, enumerate, and characterize the CTC in the peripheral circulation of patients with HCC. PMID:22690340

  9. 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.

  10. FLT3 ligand administration after hematopoietic cell transplantation increases circulating dendritic cell precursors that can be activated by CpG oligodeoxynucleotides to enhance T-cell and natural killer cell function.

    PubMed

    Chen, Wei; Chan, Anissa S H; Dawson, Amanda J; Liang, Xueqing; Blazar, Bruce R; Miller, Jeffrey S

    2005-01-01

    Dendritic cells (DCs) are key effectors in innate immunity and play critical roles in triggering adaptive immune responses. FLT3 ligand (FLT3-L) is essential for DC development from hematopoietic progenitors. In a phase I clinical trial, we demonstrated that immunotherapy with subcutaneous injection of FLT3-L is safe and well tolerated in cancer patients recovering from autologous hematopoietic cell transplantation (HCT). FLT3-L administration significantly increased the frequency and absolute number of blood DC precursors without affecting other mature cell lineages during the 6-week course of FLT3-L therapy. After 14 days of FLT3-L administration, the number of blood CD11c + DCs, plasmacytoid DCs (PDCs), and CD14 + monocytes increased by 5.3-, 2.9-, 3.8-fold, respectively, and was maintained at increased levels throughout FLT3-L therapy. FLT3-L-increased blood DCs in HCT patients were immature and had modest enhancing effects on in vitro T-cell proliferation to antigens and natural killer (NK) cell function. The addition of type B CpG oligodeoxynucleotides (ODNs) to peripheral blood mononuclear cells obtained from HCT patients receiving FLT3-L therapy induced rapid maturation of both CD11c + DCs and PDCs and enhanced T-cell proliferative responses. In addition, CpG ODN induced potent activation of NK cells from FLT3-L-treated patients with increased surface CD69 expression and augmented cytotoxicity. CpG ODN-induced activation of NK cells was primarily via an indirect mechanism through PDCs. These findings suggest that FLT3-L mobilization of DC precursors followed by a specific DC stimulus such as CpG ODN may provide a novel strategy to manipulate antitumor immunity in patients after HCT. PMID:15625541

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. Changes in large-scale air circulation and connection with climate variables in Romania

    NASA Astrophysics Data System (ADS)

    Stefan, Sabina; Barbu, Nicu

    2016-04-01

    The aim of this paper is the analysis of the relationship between climate variables (seasonal mean air temperature - T2m, and seasonal amount of precipitation - PP) and large-scale air circulation. In order to achieve this, the air circulation types were derived from GrossWetterTypen (GWT) and WetterLagenKlassifikation (WLK) Catalogues developed within COST733 framework. Daily air circulation types are divided into 18 groups according to the GWT Catalogue and in 40 groups according to the WLK Catalogue and for each type winter (DJF) and summer (JJA) occurrence frequency were calculated. To this end the Pearson correlation coefficient between climate variables and circulation type's frequency were computed. The results reveals that in wintertime the GWT circulation types captures better than WLK circulation types the T2m variability in time that for summer the WLK circulation types captures better than GWT circulation types. This is due to the seasonal variability of the horizontal extension of air masses. We found that the T2m is positive correlated to anticyclonic circulation types and negative correlated with cyclonic types and the PP is correlated to the cyclonic circulation and negative correlated to anticyclonic ones. Additionally, the trend significance of the climate variables as well as air circulation types have been analysed with the non-parametric Mann-Kendall test. The changes of the trends were detected by employing the non-parametric Pettit test. From the trend analysis we can state that some of the anticyclonic circulation types presents upward tendency and some of the cyclonic circulation presents downward tendency. This is an important results because explain the upward trend of the T2m and the downward trend of the PP.

  16. 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

  17. 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

  18. Circulation of HRSV in Belgium: from multiple genotype circulation to prolonged circulation of predominant genotypes.

    PubMed

    Houspie, Lieselot; Lemey, Philippe; Keyaerts, Els; Reijmen, Eva; Vergote, Valentijn; Vankeerberghen, Anne; Vaeyens, Freya; De Beenhouwer, Hans; Van Ranst, Marc

    2013-01-01

    Molecular surveillance of HRSV in Belgium for 15 consecutive seasons (1996-2011) revealed a shift from a regular 3-yearly cyclic pattern, into a yearly alternating periodicity where HRSV-B is replaced by HRSV-A. Phylogenetic analysis for HRSV-A demonstrated the stable circulation of GA2 and GA5, with GA2 being dominant over GA5 during 5 consecutive seasons (2006-2011). We also identified 2 new genotype specific amino acid mutations of the GA2 genotype (A122 and Q156) and 7 new GA5 genotype specific amino acid mutations (F102, I108, T111, I125, D161, S191 and L217). Several amino acid positions, all located in the second hypervariable region of HRSV-A were found to be under positive selection. Phylogenetic analysis of HRSV-B showed the circulation of GB12 and GB13, where GB13 represented 100% of the isolated strains in 4 out of 5 consecutive seasons (2007-2011). Amino acids under positive selection were all located in the aminoterminal hypervariable region of HRSV-B, except one amino acid located in the conserved region. The genotype distribution within the HRSV-B subgroup has evolved from a co-circulation of multiple genotypes to the circulation of a single predominant genotype. The Belgian GB13 strains circulating since 2006, all clustered under the BAIV branch and contained several branch specific amino acid substitutions. The demographic history of genotypes GA2, GA5 and GB13 demonstrated a decrease in the total GA2 and GA5 population size, coinciding with the global expansion of the GB13 population. The emergence of the GB13 genotype resulted in a newly established balance between the predominant genotypes. PMID:23577109

  19. 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.

  20. All-glass vacuum tube collector heat transfer model used in forced-circulation solar water heating system

    SciTech Connect

    Li, Zhiyong; Chen, Chao; Luo, Hailiang; Zhang, Ye; Xue, Yaning

    2010-08-15

    The aim of this paper is to establish the heat transfer model of all-glass vacuum tube collector used in forced-circulation solar water heating system. In this model, the simplified heat transfer of collector is composed of the natural convection in single glass tube and forced flow in manifold header. Thus the heat balance equation of water in single tube and the heat balance equation of water in manifold header have been established. The flow equation is also built by analyzing the friction and buoyancy in tube. Through solved these equations the relationship between the collector average temperature, the outlet temperature and natural convection flow rate have been obtained. From this relationship and energy balance equation of collector, the collector outlet temperature can be calculated. The validated experiments of this model were carried out in winter of Beijing. (author)

  1. 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.

  2. Circulating epigenetic biomarkers in melanoma.

    PubMed

    Xin, Yu; Li, Zheng; Chan, Matthew T V; Wu, William Ka Kei

    2016-02-01

    Recent researches have shed new light on the importance of epigenetic alterations, including promoter hypermethylation and microRNA dysregulation, in the initiation and progression of melanoma. The clinical utilization of circulating epigenetic markers in melanoma has also been investigated. In this review, we explored the literature and summarized the latest progress in the discovery of circulating epigenetic markers, namely methylated DNA and microRNAs, for non-invasive diagnosis of melanoma, as well as their measurability and predictability. We also discussed the utility of these epigenetic markers as novel prognostic and predictive markers and their association with melanoma clinical phenotypes, including recurrence and patients' survival. Large-cohort validations are warranted to maximize the clinical utilization of these markers. PMID:26662802

  3. Circulating immune complexes in sarcoidosis.

    PubMed Central

    Johnson, N M; NcNicol, M W; Burton-Kee, J E; Mowbray, J F

    1980-01-01

    The sera of 50 patients with sarcoidosis were tested for the presence of circulating immune complexes using polyethylene glycol precipitation, followed by single radial immuno diffusion for the amounts of Clg, IgG, IgM, and double diffusion for the presence of IgA. Complexes were detected in 29 (58%) patients. No correlation could be found between the presence of these complexes and the length of history stage, or activity of disease, nor to steroid therapy. Rheumatoid factor was detected in 14 patients (28%), 13 of whom had circulating immune complexes, and 12 of whom had active disease. Total serum C3, CH50, and Clq were normal, as were immunoglobulin levels. In patients with extrathoracic sarcoidosis, especially skin or joint involvement, complexes were commonly found. The aetiological significance of these complexes remains uncertain. PMID:7434270

  4. 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. PMID:11089118

  5. Blood circulation under weightless conditions

    NASA Technical Reports Server (NTRS)

    Kasyan, I. I.; Kopanev, V. I.; Yazdovskiy, V. I.

    1975-01-01

    Biomedical data obtained on men and animals during weightlessness conditions establish instabilities in pulse rate and blood circulation that smooth out in proportion to adaptation to the weightless condition. The unusual slowness of recovery of pulse rate to initial values after space flight stress is attributed to biological simulation of hormonal shifts and discharge of humoral substances into the blood that prevent a rapid recovery of some biological indicators to initial values.

  6. On the effect of domain size on the relationship between circulation types and surface climate

    NASA Astrophysics Data System (ADS)

    Beck, Christoph

    2010-05-01

    Circulation type classifications are often used for analysing the link between large-scale atmospheric circulation and surface climate (e.g. within statistical downscaling studies). Evaluation and comparison studies that have been performed within the framework of the EU COST Action 733 "Harmonisation and Applications of Weather Type Classifications for European regions" have shown that apart from methodological differences among varying classification concepts the relationship between circulation types and surface climate parameters is largely dependent on a number of "boundary conditions" that are independent of the respectively applied classification method (e.g. number of designated circulation types, atmospheric level to which the classification is applied). In this contribution the effect of varying domain size on the relationship between circulation types and surface climate parameters is investigated on the basis of a set of automated circulation type classifications from the COST 733 database of circulation classfications. To this end several circulation classifications (threshold based approaches, PCA-based methods, leader and optimization algorithms) have been applied iteratively to domains of differing size, each of them centered over a specific "target domain" of fixed size within the North-Atlantic European region. Based on the resulting circulation type catalogues and surface climate data for the respective "target domains" (daily gridded and station data for temperature and precipitation) varying evaluation metrics have been calculated in order to quantify the performance of each classification depending on the size of the domain used for classification.

  7. 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)

  8. 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.

  9. 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.

  10. 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).

  11. First-principles calculation of the 17O NMR parameters in Ca oxide and Ca aluminosilicates: the partially covalent nature of the Ca-O bond, a challenge for density functional theory.

    PubMed

    Profeta, Mickaël; Benoit, Magali; Mauri, Francesco; Pickard, Chris J

    2004-10-01

    We apply density functional theory (DFT) to the calculation of the (17)O NMR parameters in Ca and Mg oxides and aluminosilicates. We study the accuracy of the Perdew, Burke, and Ernzerhof (PBE) generalized-gradient approximation to DFT in the description of these systems and the origin of the experimentally observed large dependence of the (17)O chemical shift on the alkaline earth ion. We find that (i) the partially covalent nature of the Ca-O bond has a huge impact on the O chemical shifts. The Ca-O covalence alone explains why in Ca oxides and aluminosilicates the (17)O chemical shifts are much more deshielded than those of the corresponding Mg compounds. (ii) The Ca-O covalence is overestimated by the PBE functional. Thus PBE-DFT is not able to reproduce the measured (17)O NMR parameters in Ca oxide and Ca aluminosilicates. (iii) It is possible to correct for the PBE-DFT deficiency in a simple and transferable way and to predict very accurate (17)O NMR parameters. Such accuracy allows us to assign the (17)O NMR spectra of two important model systems: the grossite aluminate (CaAl(4)O(7)) and the wollastonite (CaSiO(3)) silicate.

  12. Equilibrium calculations of firework mixtures

    SciTech Connect

    Hobbs, M.L.; Tanaka, Katsumi; Iida, Mitsuaki; Matsunaga, Takehiro

    1994-12-31

    Thermochemical equilibrium calculations have been used to calculate detonation conditions for typical firework components including three report charges, two display charges, and black powder which is used as a fuse or launch charge. Calculations were performed with a modified version of the TIGER code which allows calculations with 900 gaseous and 600 condensed product species at high pressure. The detonation calculations presented in this paper are thought to be the first report on the theoretical study of firework detonation. Measured velocities for two report charges are available and compare favorably to predicted detonation velocities. However, the measured velocities may not be true detonation velocities. Fast deflagration rather than an ideal detonation occurs when reactants contain significant amounts of slow reacting constituents such as aluminum or titanium. Despite such uncertainties in reacting pyrotechnics, the detonation calculations do show the complex nature of condensed phase formation at elevated pressures and give an upper bound for measured velocities.

  13. 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.

  14. 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.

  15. Conveying Global Circulation Patterns in HDTV

    NASA Astrophysics Data System (ADS)

    Gardiner, N.; Janowiak, J.; Kinzler, R.; Trakinski, V.

    2006-12-01

    The American Museum of Natural History has partnered with the National Centers for Environmental Prediction (NCEP) to educate general audiences about weather and climate using high definition video broadcasts built from half-hourly global mosaics of infrared (IR) data from five geostationary satellites. The dataset being featured was developed by NCEP to improve precipitation estimates from microwave data that have finer spatial resolution but poorer temporal coverage. The IR data span +/-60 degrees latitude and show circulation patterns at sufficient resolution to teach informal science center visitors about both weather and climate events and concepts. Design and editorial principles for this media program have been guided by lessons learned from production and annual updates of visualizations that cover eight themes in both biological and Earth system sciences. Two formative evaluations on two dates, including interviews and written surveys of 480 museum visitors ranging in age from 13 to over 60, helped refine the design and implementation of the weather and climate program and demonstrated that viewers understood the program's initial literacy objectives, including: (1) conveying the passage of time and currency of visualized data; (2) geographic relationships inherent to atmospheric circulation patterns; and (3) the authenticity of visualized data, i.e., their origin from earth-orbiting satellites. Surveys also indicated an interest and willingness to learn more about weather and climate principles and events. Expanded literacy goals guide ongoing, biweekly production and distribution of global cloud visualization pieces that reach combined audiences of approximately 10 million. Two more rounds of evaluation are planned over the next two years to assess the effectiveness of the media program in addressing these expanded literacy goals.

  16. Natural convection heat transfer simulation using energy conservative dissipative particle dynamics.

    PubMed

    Abu-Nada, Eiyad

    2010-05-01

    Dissipative particle dynamics with energy conservation (eDPD) was used to study natural convection via Rayleigh-Bénard (RB) problem and a differentially heated enclosure problem (DHE). The current eDPD model implemented the Boussinesq approximation to model the buoyancy forces. The eDPD results were compared to the finite volume solutions and it was found that the eDPD method predict the temperature and flow fields throughout the natural convection domains properly. The eDPD model recovered the basic features of natural convection, such as development of plumes, development of thermal boundary layers, and development of natural convection circulation cells (rolls). The eDPD results were presented via temperature isotherms, streamlines, velocity contours, velocity vector plots, and temperature and velocity profiles. Further useful quantities, such as Nusselt number was calculated from the eDPD results and found to be in good agreement with the finite volume calculations.

  17. Are flood occurrences in Europe linked to specific atmospheric circulation types?

    NASA Astrophysics Data System (ADS)

    Prudhomme, C.; Genevier, M.

    2009-04-01

    N* of CTi using historical frequencies of occurrence. N* represents the number of days preceding a flood when the atmospheric conditions could significantly influence flood production processes, and could be interpreted as an upper limit of the concentration time of the basin. This evaluates the persistence of an atmospheric circulation type CTi prior to a flood event, and the associated level of significance. The indicators are calculated at-site and discussed regionally. Results show significant links with two circulation types related to Cyclonic Westerly (Wz) and the Low over the British Isles (TB), while the anticyclonic north-westerly type (Nea) systematically doesn't occur before any flood event. References Barredo, J.I., 2007. Major flood disasters in Europe: 1950-2005. Natural Hazards and Earth System Sciences, 42 doi: 10.1007/s11069-006-9065-2: 125-148. Hess, P. and Brezowsky, H., 1977. Katalog der Grobwetterlagen Europas 1881-1976. 3 verbesserte und ergäntze Auflage. Ber Dt. Wetterd. 15 (113). James, P.M., 2007. An objective classification method for Hess and Brezowsky Grosswetterlagen over Europe. Theoretical and Applied Climatology, 88(1): 17-42.

  18. 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.

  19. Metastasis and Circulating Tumor Cells.

    PubMed

    van Dalum, Guus; Holland, Linda; Terstappen, Leon Wmm

    2012-10-01

    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.

  20. 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

  1. 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.

  2. Lost circulation experience in geothermal wells

    SciTech Connect

    Goodman, M.A.

    1981-01-01

    Assessment of the general drilling and completion practices commonly used for handling lost circulation have been surveyed and evaluated under a study sponsored by Sandia National Laboratories. Results of this study, including interviews with geothermal production companies and with drilling fluid service companies, are reported. Lost circulation in geothermal wells is generally very different from lost circulation in petroleum wells. Conventional lost circulation materials and squeeze cementing are not always successful in the cavernous and vugular low-pressure formations encountered in geothermal reservoirs. Special completion methods, such as liner and tieback string, are often used to improve cement placement and setting in lost circulation zones. High wellbore temperatures during geothermal cementing magnify the lost circulation problem. Cement retarders may be needed to prevent premature setting at the higher temperatures, yet too much retarder may lead to an unsuccessful completion, particularly because of the large volume of cement that may be required to seal a lost circulation zone. Conclusions and recommendations are presented for control of lost circulation during geothermal operations. Recent improvements in lost circulation materials and techniques and potential equipment solutions to the lost circulation problem are discussed. Research needs are also identified.

  3. 14C-age tracers in global ocean circulation models

    NASA Astrophysics Data System (ADS)

    Koeve, W.; Wagner, H.; Kähler, P.; Oschlies, A.

    2015-07-01

    The natural abundance of 14C in total CO2 dissolved in seawater (DIC) is a property applied to evaluate the water age structure and circulation in the ocean and in ocean models. In this study we use three different representations of the global ocean circulation augmented with a suite of idealised tracers to study the potential and limitations of using natural 14C to determine water age, which is the time elapsed since a body of water has been in contact with the atmosphere. We find that, globally, bulk 14C-age is dominated by two equally important components, one associated with ageing, i.e. the time component of circulation, and one associated with a "preformed 14C-age". The latter quantity exists because of the slow and incomplete atmosphere-ocean equilibration of 14C particularly in high latitudes where many water masses form. In the ocean's interior, preformed 14C-age behaves like a passive tracer. The relative contribution of the preformed component to bulk 14C-age varies regionally within a given model, but also between models. Regional variability in the Atlantic Ocean is associated with the mixing of waters with very different end members of preformed 14C-age. Here, variations in the preformed component over space and time mask the circulation component to an extent that its patterns are not detectable from bulk 14C-age. Between models, the variability of preformed 14C-age can also be considerable (factor of 2), related to the combination of physical model parameters, which influence circulation dynamics or gas exchange. The preformed component was found to be very sensitive to gas exchange and moderately sensitive to ice cover. In our model evaluation, the choice of the gas-exchange constant from within the currently accepted range of uncertainty had such a strong influence on preformed and bulk 14C-age that if model evaluation would be based on bulk 14C-age, it could easily impair the evaluation and tuning of a model's circulation on global and regional

  4. 14C-age tracers in global ocean circulation models

    NASA Astrophysics Data System (ADS)

    Koeve, W.; Wagner, H.; Kähler, P.; Oschlies, A.

    2014-10-01

    The natural abundance of 14C in total CO2 dissolved in seawater is a property applied to evaluate the water age structure and circulation in the ocean and in ocean models. In this study we use three different representations of the global ocean circulation augmented with a suite of idealised tracers to study the potential and limitations of using natural 14C to determine water age, the time elapsed since a body of water had contact with the atmosphere. We find that, globally, bulk 14C-age is dominated by two equally important components, one associated with aging, i.e. the time component of circulation and one associated with a "preformed 14C-age". This latter quantity exists because of the slow and incomplete atmosphere/ocean equilibration of 14C in particular in high latitudes where many water masses form. The relative contribution of the preformed component to bulk 14C-age varies regionally within a given model, but also between models. Regional variability, e.g. in the Atlantic Ocean is associated with the mixing of waters with very different end members of preformed 14C-age. In the Atlantic, variations in the preformed component over space and time mask the circulation component to an extent that its patterns are not detectable from bulk 14C-age alone. Between models the variability of age can also be considerable (factor of 2), related to the combinations of physical model parameters, which influence circulation dynamics, and gas exchange in the models. The preformed component was found to be very sensitive to gas exchange and moderately sensitive to ice cover. In our model evaluation exercise, the choice of the gas exchange constant from within the current range of uncertainty had such a strong influence on preformed and bulk 14C-age that if model evaluation would be based on bulk 14C-age it could easily impair the evaluation and tuning of a models circulation on global and regional scales. Based on the results of this study, we propose that considering

  5. Wind-induced variability of estuarine circulation in a tidally energetic inlet with curvature

    NASA Astrophysics Data System (ADS)

    Purkiani, Kaveh; Becherer, Johannes; Klingbeil, Knut; Burchard, Hans

    2016-05-01

    In numerous studies, the functioning of estuarine circulation has been investigated, under idealized conditions, by means of numerical models. This has led to a deep understanding of the theory of estuarine residual flows. However, the question as to how estuarine circulation is established in real estuaries, in response to their topographical and forcing characteristics, remains. The present study uses a highly accurate three-dimensional numerical model simulation to calculate estuarine circulation in a curved, tidally energetic channel of the Wadden Sea in the southeastern North Sea. The specific momentum balance of this curved inlet shows an approximate pressure-gradient—frictional balance in the longitudinal direction and a pressure gradient—centrifugal balance in the lateral direction. A local Wedderburn number is introduced to quantify the varying contributions of wind stress and gravitational forcing on estuarine circulation. A total exchange flow (TEF) analysis is combined with an analysis of the intensity of the vertical overturning circulation to understand the dynamics of estuarine exchange in this inlet. The results show how established forcing mechanisms of residual circulation, such as horizontal buoyancy gradients and wind stress, act in a combined way. In general, the strength of estuarine circulation is always positively correlated with wind stress, with frequent reversals of residual flow for wind stress directed toward higher buoyancy. Only during calm weather conditions are longitudinal and lateral estuarine circulation highly correlated with the respective buoyancy gradients.

  6. 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.

  7. Lost Circulation Experience in Geothermal Wells

    SciTech Connect

    Goodman, M. A.

    1981-01-01

    Lost circulation during drilling and cementing in geothermal wells is a problem common to most geothermal areas. Material and rig time costs due to lost circulation often represent one fourth or more of the total well cost. Assessment of the general drilling and completion practices commonly used for handling lost circulation have been surveyed and evaluated under a study sponsored by Sandia National Laboratories. Results of this study, including interviews with geothermal production companies and with drilling fluid service companies, are reported in the paper. Conclusions and recommendations are presented for control of lost circulation during geothermal operations. Recent improvements in lost circulation materials and techniques and potential equipment solutions to the lost circulation problem are discussed. Research needs are also identified.

  8. On the North Atlantic Circulation

    NASA Astrophysics Data System (ADS)

    Schmitz, William J.; McCartney, Michael S.

    1993-02-01

    A new, speculative, and, we hope, provocative summary of the North Atlantic circulation is described, including both horizontal currents (wind-driven) and the primarily (thermohaline) meridional flows that involve the transformation of warm to cold water at high latitudes. Our picture is based on a synthesis of a variety of independent investigations that are contained in the literature as opposed to a presentation of the results of one technique or the point of view of one author. We describe a thermohaline cell (the so-called thermohaline conveyor belt) that is concentrated within the Atlantic and Southern oceans (rather than essentially global), with the most important upwelling sites being in the circumpolar and the equatorial current regimes. We concentrate on deep water formation and its replacement relative to intermediate-water formation. It has been pointed out recently that the formation of 13 Sv (1 Sv = 106 m³ s-1) of southward flowing North Atlantic Deep Water is compensated for in the upper ocean by northward cross-equatorial transport. We suggest that this thermocline layer flow passes through the Straits of Florida, transits the Gulf Stream system on its inshore side, and exits through the North Atlantic Current system after recirculation and modification. There is now a clear observational basis for the structure of recirculating gyres on the southern and northern sides of the Gulf Stream. We suggest a recirculation for the North Atlantic Current as well. We also describe a C-shaped component to the southern Gulf Stream recirculation and identify a roughly 10-Sv circulation in the eastern North Atlantic associated with the Azores Current. Recirculations play an important role in deep boundary current regimes and in water mass formation and modification. The transport of the deep western and northern boundary currents in the North Atlantic Ocean may be boosted (roughly doubled or tripled) by counterclockwise recirculating gyres and by additions of

  9. 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,...

  10. Three port optical circulators with ring resonators

    NASA Astrophysics Data System (ADS)

    Jalas, Dirk; Petrov, Alexander Y.; Eich, Manfred

    2014-05-01

    We present a concept for a circulator that has the same bandwidth efficiency as a photonic crystal circulator but which relies on a ring resonator and thereby is experimentally much easier to realize. We achieve this by side coupling three waveguides to the ring resonator. The desired standing wave pattern which recreates the photonic crystal type circulator spectrum is realized by exciting both the clockwise and counter-clockwise traveling wave through a Bragg reflector.

  11. 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.

  12. Numerical simulation and prediction of coastal ocean circulation

    SciTech Connect

    Chen, P.

    1992-01-01

    Numerical simulation and prediction of coastal ocean circulation have been conducted in three cases. 1. A process-oriented modeling study is conducted to study the interaction of a western boundary current (WBC) with coastal water, and its responses to upstream topographic irregularities. It is hypothesized that the interaction of propagating WBC frontal waves and topographic Rossby waves are responsible for upstream variability. 2. A simulation of meanders and eddies in the Norwegian Coastal Current (NCC) for February and March of 1988 is conducted with a newly developed nested dynamic interactive model. The model employs a coarse-grid, large domain to account for non-local forcing and a fine-grid nested domain to resolve meanders and eddies. The model is forced by wind stresses, heat fluxes and atmospheric pressure corresponding Feb/March of 1988, and accounts for river/fjord discharges, open ocean inflow and outflow, and M[sub 2] tides. The simulation reproduced fairly well the observed circulation, tides, and salinity features in the North Sea, Norwegian Trench and NCC region in the large domain and fairly realistic meanders and eddies in the NCC in the nested region. 3. A methodology for practical coastal ocean hindcast/forecast is developed, taking advantage of the disparate time scales of various forcing and considering wind to be the dominant factor in affecting density fluctuation in the time scale of 1 to 10 days. The density field obtained from a prognostic simulation is analyzed by the empirical orthogonal function method (EOF), and correlated with the wind; these information are then used to drive a circulation model which excludes the density calculation. The method is applied to hindcast the circulation in the New York Bight for spring and summer season of 1988. The hindcast fields compare favorably with the results obtained from the prognostic circulation model.

  13. General circulation model sensitivity experiments with pole-centered supercontinents

    SciTech Connect

    Crowley, T.J.; Baum, S.K.; Kim, Kwang-Yul )

    1993-05-20

    The authors present model studies related to the general question of whether there could have been nearly ice-free climates in the past history of the Earth. Energy balance models and general circulation model calculations have addressed this question. In general this appears impossible, even with moving continents around, without postulating enhanced levels of CO[sub 2]. Early work indicated that pole centered continents could have snow free summers, but later work, with models with better physics, but poorer resolution seemed to contradict this conclusion. The authors apply the GENESIS (ver 1.02) general circulation model to this problem. Their conclusion is that with certain modifications to the application of this model, they could find pole-centered supercontinents which would be snow free in the summer.

  14. Langmuir circulations beneath growing waves

    NASA Astrophysics Data System (ADS)

    Phillips, W. R. C.

    2000-11-01

    The instability of a weakly sheared density stratified two dimensional wavy flow to longitudinal vortices is considered. The instability mechanism is Craik-Leibovich type 2, or CL2, and the problem is posited in the context of Langmuir circulations beneath irrotational wind driven surface waves. Of interest is the influence to the instability of growing or decaying waves according to linear theory. The basis for the study is an initial value problem posed by Leibovich & Paolucci (1981) in which the liquid substrate is of semi-infinite extent and the wind driven current is permitted to grow. At zero Richardson number, relative to the solution for neutral waves, it is found that growing waves act to stabilize the instability while decaying waves are destablizing. Furthemore while growing waves act to increase the spanwise wavenumber at onset, decaying waves act to decrease it. The influence of Prandtl and Richardson numbers is also discussed.

  15. 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.

  16. Meridional Circulation and Global Solar Oscillations

    NASA Astrophysics Data System (ADS)

    Roth, M.; Stix, M.

    2008-09-01

    We investigate the influence of large-scale meridional circulation on solar p-modes by quasi-degenerate perturbation theory, as proposed by Lavely & Ritzwoller, 1992 (Roy. Soc. Lon. Phil. Trans. Ser. A, 339, 431). As an input flow we use various models of stationary meridional circulation obeying the continuity equation. This flow perturbs the eigenmodes of an equilibrium model of the Sun. We derive the signatures of the meridional circulation in the frequency multiplets of solar p modes. In most cases the meridional circulation leads to negative average frequency shifts of the multiplets. Further possibly observable effects are briefly discussed.

  17. Meridional Circulation and Global Solar Oscillations

    NASA Astrophysics Data System (ADS)

    Roth, M.; Stix, M.

    2008-09-01

    We investigate the influence of large-scale meridional circulation on solar p modes by quasi-degenerate perturbation theory, as proposed by Lavely and Ritzwoller ( Roy. Soc. Lond. Phil. Trans. Ser. A 339, 431, 1992). As an input flow we use various models of stationary meridional circulation obeying the continuity equation. This flow perturbs the eigenmodes of an equilibrium model of the Sun. We derive the signatures of the meridional circulation in the frequency multiplets of solar p modes. In most cases the meridional circulation leads to negative average frequency shifts of the multiplets. Further possibly observable effects are briefly discussed.

  18. 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.

  19. A brief etymology of the collateral circulation.

    PubMed

    Faber, James E; Chilian, William M; Deindl, Elisabeth; van Royen, Niels; Simons, Michael

    2014-09-01

    It is well known that the protective capacity of the collateral circulation falls short in many individuals with ischemic disease of the heart, brain, and lower extremities. In the past 15 years, opportunities created by molecular and genetic tools, together with disappointing outcomes in many angiogenic trials, have led to a significant increase in the number of studies that focus on: understanding the basic biology of the collateral circulation; identifying the mechanisms that limit the collateral circulation's capacity in many individuals; devising methods to measure collateral extent, which has been found to vary widely among individuals; and developing treatments to increase collateral blood flow in obstructive disease. Unfortunately, accompanying this increase in reports has been a proliferation of vague terms used to describe the disposition and behavior of this unique circulation, as well as the increasing misuse of well-ensconced ones by new (and old) students of collateral circulation. With this in mind, we provide a brief glossary of readily understandable terms to denote the formation, adaptive growth, and maladaptive rarefaction of collateral circulation. We also propose terminology for several newly discovered processes that occur in the collateral circulation. Finally, we include terms used to describe vessels that are sometimes confused with collaterals, as well as terms describing processes active in the general arterial-venous circulation when ischemic conditions engage the collateral circulation. We hope this brief review will help unify the terminology used in collateral research.

  20. 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.

  1. Vascular impedance analysis in human pulmonary circulation.

    PubMed

    Zhou, Qinlian; Gao, Jian; Huang, Wei; Yen, Michael

    2006-01-01

    Vascular impedance is determined by morphometry and mechanical properties of the vascular system, as well as the rheology of the blood. The interactions between all these factors are complicated and difficult to investigate solely by experiments. A mathematical model representing the entire system of human pulmonary circulation was constructed based on experimentally measured morphometric and elasticity data of the vessels. The model consisted of 16 orders of arteries and 15 orders of veins. The pulmonary arteries and veins were considered as elastic tubes and their impedance was calculated based on Womersley's theory. The flow in capillaries was described by the "sheet-flow" theory. The model yielded an impedance modulus spectrum that fell steeply from a high value at 0 Hz to a minimum around 1.5 Hz. At about 4 Hz, it reached a second high and then oscillated around a relatively small value at higher frequencies. Characteristic impedance was 27.9 dyn-sec/cm5. Influence of variations in vessel geometry and elasticity on impedance spectra was analyzed. Simulation results showed good agreement with experimental measurements. PMID:16817653

  2. 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.

  3. Abundances anomalies and meridional circulation in horizontal branch stars

    NASA Astrophysics Data System (ADS)

    Quievy, D.; Charbonneau, P.; Michaud, G.; Richer, J.

    2009-06-01

    Context: Photospheric chemical abundances on the horizontal branch (HB) show some striking variations with effective temperature (T_eff). The most straightforward explanation is that these anomalies develop through diffusion processes, in particular gravitational settling and radiative levitation. However, the abrupt disappearance of strong abundance anomalies as one moves below about 11 000 K on the HB suggests that another factor plays an important role. Aims: We test an extension to the HB of the diffusion model for main-sequence HgMn stars, where strong anomalies can only develop in the slower rotators. In these rotators the gravitational settling of helium leads to the disappearance of its superficial convection zone, so that chemical separation by radiative levitation can occur all the way to the photosphere. Methods: More specifically, we calculate the critical rotational velocity at which He settling is prevented by rotationally-induced meridional circulation, in a suite of stellar models spanning the zero-age HB. Helium settling serves as the measure of the atomic diffusion of all species. Results: Our abundance evolution calculations show that, for models with T_eff less than about 11 500 K, corresponding to stars typically observed with the same metal composition as giants, meridional circulation is efficient enough to suppress He settling for rotational velocities, in good agreement with observed values. Once the meridional circulation profile of a star rotating as a near rigid body has been adopted, no adjustable parameter is involved. Conclusions: The T_eff dependence of abundance anomalies observed on the HB can be explained by atomic diffusion transport if one introduces the competition of meridional circulation with the observed T_eff dependence of rotation velocity of HB stars.

  4. 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

  5. The Hydrothermal Circulation of the Atmosphere

    NASA Astrophysics Data System (ADS)

    Kjellsson, J.; Doos, K.; Laliberté, F. B.; Zika, J. D.

    2012-12-01

    The atmospheric circulation maintains the energy balance between the warm/moist regions and the colder/drier regions of the Earth. A well-studied aspect of the atmospheric circulation is the time-averaged zonal-mean meridional overturning circulation. The meridional overturning describes the Hadley, Ferrel and Polar Cells in each hemisphere. However, in isobaric coordinates, the zonal average is unable to capture zonally asymmetric features such as the Walker circulation and transient exchanges of heat and moisture. The Walker Circulation is restricted to equatorial regions, and is commonly studied using a meridional mean over a limited region with ill-defined latitudinal boundaries. The Walker Circulation is thus neither mass-conserving nor uniquely defined. To overtcome these limitations, the Walker circulation is often diagnosed using vertical velocity. As a consequence, it is difficult to distinguish between the zonal-mean circulation (Hadley Circulation) and the zonal asymmetries (Walker Circulation). Global mass and energy transport is here investigated using a moisture-heat perspective. A hydrothermal streamfunction is defined where latent heat and dry static energy act as coordinates. Because the hydrothermal streamfunction resides in purely thermodynamical space, it does not differentiate between zonal, meridional, or vertical transports. The hydrothermal streamfunction shows the global overturning circulation as a unified cycle. It describes a cycle with three branches: i) a convective branch where latent heat is converted into sensible heat along moist adiabats, ii) a cooling branch where dry air loses energy due to radiative damping and iii) a return branch where cold, dry air is heated and moistened following the Clausius-Clapeyron relationship. These three branches form a single cell of more than 400 Sv with at least 100 Sv due to zonal motions such as the Walker Circulation. The cell is also found fairly stationary on seasonal and inter

  6. Satellite studies of turbidity and circulation patterns in Delaware Bay

    NASA Technical Reports Server (NTRS)

    Klemas, V.; Srna, R.; Treasure, W. M.; Rogers, R.

    1973-01-01

    Satellite imagery from four successful ERTS-1 passes over Delaware Bay during different portions of the tidal cycle are interpreted with special emphasis on visibility of suspended sediment and its use as a natural tracer for gross circulation patters. The MSS red band (band 5) appears to give the best contrast, although the sediment patterns are represented by only a few neighboring shades of grey. Color density slicing improves the differentiation of turbidity levels. However, color additive enhancements are of limited value since most of the information is in a single color band. The ability of ERTS-1 to present a synoptic view of the surface circulation over the entire bay is shown to be a valuable and unique contribution of ERTS-1 to coastal oceanography.

  7. Targeted In-Situ Remediation with hydraulically regulated Alcohol Circulation using Groundwater-Circulation-Well (GCW)

    NASA Astrophysics Data System (ADS)

    Heinrich, K.; Mohrlok, U.

    2003-04-01

    At the Institute for Hydromechanics (IfH), University of Karlsruhe, two dimensional experiments are conducted with a Groundwater-Circulation-Well (GCW) to investigate water and alcohol circulations. The aim of this research is the hydraulically regulated simultaneous circulation of water and alcohol in the groundwater zone for targeted in-situ remediation. To develop a stable water circulation it is necessary to have streamlines perpendicular to the infiltration and exfiltration filter, respectively. Such a circulation defines a specific form of potential lines with corresponding streamlines which have to be conserved even if alcohol circulates by varying the flow rate of the alcohol circulation with respect to the different physical properties. To understand properly the alcohol/water circulation it is necessary to have a detailed experimental concept. This concept includes several experiments like visualisation of only water and water/alcohol circulation, Uranin tracer test and alcohol/water circulation with sampling. As main results these experiments prove that it is possible to have a hydraulically regulated simultaneous circulation of water and alcohol. Furthermore it is possible to predict the behavior of the alcohol circulation with Uranin tracer.

  8. 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.

  9. 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…

  10. 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…

  11. 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.

  12. 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.

  13. 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

  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. Circulating tumour cells and circulating free nucleic acid as prognostic and predictive biomarkers in colorectal cancer.

    PubMed

    Lim, S H; Becker, T M; Chua, W; Caixeiro, N J; Ng, W L; Kienzle, N; Tognela, A; Lumba, S; Rasko, J E J; de Souza, P; Spring, K J

    2014-04-28

    The detection of circulating tumour cells or circulating free tumour nucleic acids can potentially guide treatment and inform prognosis in colorectal cancer using minimally invasive "liquid biopsies". Current literature supports the notion that high circulating tumour cell counts or presence of tumour nucleic acid correlate with inferior clinical outcomes for patients, but they are not yet part of routine clinical care. Future research evolves around the examination of the molecular phenotype of circulating tumour cells. The key unanswered areas include differentiating between circulating tumour cell presence and their proliferative capacity and dormancy, identifying tumour heterogeneity and understanding the epithelial-mesenchymal transition.

  16. 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

  17. RF power recovery feedback circulator

    DOEpatents

    Sharamentov, Sergey I.

    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.

  18. 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

  19. 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.

  20. 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

  1. Use of the gamma-ray back-scattering technique to monitor corrosion in a circulating rig

    SciTech Connect

    Dawoud, U.M.

    1995-09-01

    The gamma back-scattering technique (GBST) was used to monitor general corrosion in situ in a steel tube installed in a circulating rig. The circulating aggressive environment was 1 wt% hydrochloric acid (HCl, pH = 0.8) at a flow rate corresponding to Reynolds number (Re) = 7,675. The final wall thickness of the steel tube resulting from accelerated corrosion as measured by GBST was 1.7 mm vs an original wall thickness of 2.8 mm. This method was compared with the standard ultrasonic technique, which agave a final thickness of 1.8 mm. The theoretical thickness calculated from weight loss and the change of tube diameter was 1.92 mm. The percentage of error against the theoretical thickness was 11.5% for GBST and 6% for the ultrasonic method. The small extra error in the GBST could be acceptable in certain situations in view of its ease of use, noncontact, and nondestructive nature.

  2. 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

  3. Serum Uric Acid Predicts Declining of Circulating Proangiogenic Mononuclear Progenitor Cells in Chronic Heart Failure Patients

    PubMed Central

    Berezin, Alexander E.; Kremzer, Alexander A.; Samura, Tatyana A.; Berezina, Tatyana A.; Martovitskaya, Yulia V.

    2014-01-01

    Introduction: Serum uric acid (SUA) is considered a marker for natural progression of chronic heart failure (CHF) mediated cardiovascular remodelling. CHF associates with declining of circulating mononuclear progenitor cells (MPCs). The objective of this study was to evaluate the interrelationship between SUA concentrations and proangiogenic MPCs in ischemic CHF patients. Methods: The study population was structured retrospectively after determining the coronary artery disease (CAD) by contrast-enhanced spiral computed tomography angiography in 126 subjects with symptomatic ischemic mild-to-severe CHF and 128 CAD subjects without CHF. Baseline biomarkers were measured in all patients. Cox proportional multivariate hazard ratio was calculated for predictors of MPCs declining in both CHF and non-CHF patient population predictors of MPCs declining in CHF subjects were examined in stepwise logistic regression. C-statistics, integrated discrimination indices (IDI) and net-reclassification improvement were utilized for prediction performance analyses. Results: Cox proportional adjusted hazard ratio analyses for CD14+CD309+ and CD14+CD309+Tie2+ MPCs by SUA has shown that the higher quartiles (Q3 and Q4) of SUA compared to the lower quartiles (Q1 and Q2) are associated with increased risks of depletion of both CD14+CD309+ and CD14+CD309+Tie2+ MPCs. The addition of Q4 SUA to the ABC model improved the relative IDI by 13.8% for depletion of CD14+CD309+ MPCs and by 14.5% for depletion of CD14+CD309+Tie2+ MPCs. Conclusion: Circulating levels of proangiogenic MPCs are declined progressively depending on the levels of SUA in the HF subjects with CHF. We suggest that even mild elevations of SUA might be used to predict of relative depletion of proangiogenic MPCs among chronic HF patients. PMID:25320662

  4. Circulating omentin concentration increases after weight loss

    PubMed Central

    2010-01-01

    Background Omentin-1 is a novel adipokine expressed in visceral adipose tissue and negatively associated with insulin resistance and obesity. We aimed to study the effects of weight loss-induced improved insulin sensitivity on circulating omentin concentrations. Methods Circulating omentin-1 (ELISA) concentration in association with metabolic variables was measured in 35 obese subjects (18 men, 17 women) before and after hypocaloric weight loss. Results Baseline circulating omentin-1 concentrations correlated negatively with BMI (r = -0.58, p < 0.001), body weight (r = -0.35, p = 0.045), fat mass (r = -0.67, p < 0.001), circulating leptin (r = -0.7, p < 0.001) and fasting insulin (r = -0.37, p = 0.03). Circulating omentin-1 concentration increased significantly after weight loss (from 44.9 ± 9.02 to 53.41 ± 8.8 ng/ml, p < 0.001). This increase in circulating omentin after weight loss was associated with improved insulin sensitivity (negatively associated with HOMA value and fasting insulin, r = -0.42, p = 0.02 and r = -0.45, p = 0.01, respectively) and decreased BMI (r = -0.54, p = 0.001). Conclusion As previously described with adiponectin, circulating omentin-1 concentrations increase after weight loss-induced improvement of insulin sensitivity. PMID:20380714

  5. 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…

  6. 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. PMID:2062096

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Circulating Peptidome to Indicate the Tumor-resident Proteolysis

    PubMed Central

    Deng, Zaian; Li, Yaojun; Fan, Jia; Wang, Guohui; Li, Yan; Zhang, Yaou; Cai, Guoping; Shen, Haifa; Ferrari, Mauro; Hu, Tony Y.

    2015-01-01

    Tumor-resident proteases (TRPs) are regarded as informative biomarkers for staging cancer progression and evaluating therapeutic efficacy. Currently in the clinic, measurement of TRP is dependent on invasive biopsies, limiting their usefulness as monitoring tools. Here we identified circulating peptides naturally produced by TRPs, and evaluated their potential to monitor the efficacy of anti-tumor treatments. We established a mouse model for ovarian cancer development and treatment by orthotopic implantation of the human drug-resistant ovarian cancer cell line HeyA8-MDR, followed by porous silicon particle- or multistage vector (MSV) - enabled EphA2 siRNA therapy. Immunohistochemistry staining of tumor tissue revealed decreased expression of matrix metallopeptidase 9 (MMP-9) in mice exhibiting positive responses to MSV-EphA2 siRNA treatment. We demonstrated, via an ex vivo proteolysis assay, that C3f peptides can act as substrates of MMP-9, which cleaves C3f at L1311-L1312 into two peptides (SSATTFRL and LWENGNLLR). Importantly, we showed that these two C3f-derived fragments detected in serum were primarily generated by tumor-resident, but not blood-circulating, MMP-9. Our results suggested that the presence of the circulating fragments specially derived from the localized cleavage in tumor microenvironment can be used to evaluate therapeutic efficacy of anti-cancer treatment, assessed through a relatively noninvasive and user-friendly proteomics approach. PMID:25788424

  13. Hybrid polyglycerols with long blood circulation: synthesis, biocompatibility, and biodistribution.

    PubMed

    Imran ul-haq, Muhammad; Lai, Benjamin F L; Kizhakkedathu, Jayachandran N

    2014-10-01

    Multifunctional polymers with defined structure and biocompatibility are critical to the development of drug delivery systems and bioconjugates. In this article, the synthesis, in vitro blood compatibility, cell viability, in vivo circulation, biodistribution, and clearance of hybrid copolymers based on linear and branched polyglycerol are reported. Hybrid polyglycerols (M(n) ≈ 100 kDa) are synthesized with different compositions (15-80 mol% linear polyglycerol). Relatively small hydrodynamic size and radius of gyration of the hybrid polyglycerols suggest that they are highly compact functional nanostructures. The hybrid polyglycerols show excellent blood compatibility as determined by measuring their effects on blood coagulation, red blood cell aggregation, hemolysis, platelet, and complement activation. The cell viability in presence of hybrid polyglycerols is excellent up to 10 mg mL(-1) concentration and is similar to both dextran and polyvinyl alcohol. Furthermore, tritium labeled hybrid polyglycerol shows long blood circulation (t(1/2β)= 34 h) with minimal organ accumulation in mice. Multifunctionality, compact nature, biocompatibility, and the long blood circulation make these polymers attractive for the development of bioconjugates and drug delivery systems.

  14. 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.

  15. 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.

  16. 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.

  17. Plateau effects on diurnal circulation patterns

    SciTech Connect

    Reiter, E.R.; Tang, M.

    1984-04-01

    The diurnal variation of 850 mb heights, the detailed distribution of which could be assessed by the inclusion of surface data, and of resultant winds over, and in the vicinity of, the Great Basin reveals clearly a plateau-wind circulation during summer. This circulation reverses between day and night and appears to include the low-level jet stream over Texas and Oklahoma, as well as the time of occurrence of thunderstorms. This plateau circulation system interacts with local mountain-valley breeze systems. The thickness of the daytime inflow and nighttime outflow layer over the plateau is approximately 2 km. 19 references, 11 figures, 1 table.

  18. 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.

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

    PubMed

    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.

  20. 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

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

    PubMed

    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

  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. Autistic Savant Calendar Calculators.

    ERIC Educational Resources Information Center

    Patti, Paul J.

    This study identified 10 savants with developmental disabilities and an exceptional ability to calculate calendar dates. These "calendar calculators" were asked to demonstrate their abilities, and their strategies were analyzed. The study found that the ability to calculate dates into the past or future varied widely among these calculators. Three…

  4. Another hint for a changing stratospheric circulation after 2001

    NASA Astrophysics Data System (ADS)

    Boenisch, H.; Engel, A.; Hoor, P.

    2009-04-01

    Aircraft data were used to study interannual changes of extratropical lower stratospheric tracer-tracer correlations. The focus is on the time periods before and after 2001 between which a remarkable step-like decrease of stratospheric water vapour has occurred (Randel et al., 2006). This feature associated with a cooling of temperatures near the tropical tropopause, and a decrease in tropical ozone at about the same time has been linked by Randel et al. (2006) to an increased stratospheric upwelling circulation in the tropics (the so-called Brewer-Dobson circulation) caused by enhanced wave driving after 2000 (Dhomse et al., 2006). Analysis of the extratropical tracer-tracer correlations shows different slopes before and after 2000. These changes could be explained by an enhanced horizontal tracer transport from the tropical lower stratosphere into the extratropics, taking into account that mean age of air has remained constant over the last 3 decades in the midlatitude stratosphere above 30 hPa (Engel et al., 2009). We will present a comparison of in-situ measured tracer-tracer correlations in the extratropical lower stratosphere before and after 2001 and discuss implications for a changing stratospheric circulation. References: Dhomse, S., Weber, M., and Burrows, J.: The relationship between tropospheric wave forcing and tropical lower stratospheric water vapor, Atmos. Chem. Phys., 8, 471-480, 2008. Engel, A., T. Möbius, H. Bönisch, U. Schmidt, R. Heinz, I. Levin, E. Atlas, S. Aoki, T. Nakazawa, S. Sugawara, F. Moore, D. Hurst, J. Elkins, S. Schauffler, A. Andrews, and K. Boering (2009), Age of stratospheric air unchanged within uncertainties over the past 30 years, Nature Geosci., 2, 28-31. Randel, W. J., F. Wu, H. Vömel, G. E. Nedoluha, and P. Forster (2006), Decreases in stratospheric water vapor after 2001: Links to changes in the tropical tropopause and the Brewer-Dobson circulation, J. Geophys. Res., 111, D12312, doi:10.1029/2005JD006744.

  5. 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.

  6. 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.

  7. 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.

  8. Global Thermohaline Circulation. Part II: Sensitivity with Interactive Atmospheric Transports.

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoli; Stone, Peter H.; Marotzke, Jochem

    1999-01-01

    A hybrid coupled ocean-atmosphere 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 I. 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 hemispheres 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.

  9. 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.

  10. 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.

  11. An online educational atmospheric global circulation model

    NASA Astrophysics Data System (ADS)

    Navarro, T.; Schott, C.; Forget, F.

    2015-10-01

    As part of online courses on exoplanets of Observatoire de Paris, an online tool designed to vizualise outputs of the Laboratoire de Métérologie Dynamique (LMD) Global Circulation Model (GCM) for various atmospheric circulation regimes has been developed. It includes the possibility for students to visualize 1D and 2D plots along with animations of atmospheric quantities such as temperature, winds, surface pressure, mass flux, etc... from a state-of-the-art model.

  12. Computer simulation of the cooling effect due to circulation in four geothermal well models

    SciTech Connect

    Duda, L.E.

    1984-11-01

    Computer calculations of wellbore transient temperatures, using the geothermal wellbore thermal simulator code GEOTEMP2, were made on four well models. The well models studied were from the Baca geothermal area, the East Mesa geothermal area, and a shallow and a deep well from the Salton Sea geothermal area. Calculations for one day of water circulation followed by one day of shut-in at flow rates of 100, 250, 500, and 1000 gpm were made to investigate the cooling effects produced by the circulation. Additional calculations were made using the Baca and Salton Sea well models. In the former, the effect on the cooling due to different soil thermal conductivity values and different circulating fluids (a high viscosity mud and air) were investigated. In the latter, the number of casings in the wellbore and the diameter of the tubing were notified. Plots of the calculated temperatures as a function of circulation and shut-in time and depth are given for each case.

  13. 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.

  14. 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.

  15. 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.

  16. The geochemical behavior of natural radionuclides in coastal waters: A modeling study for the Huelva estuary

    NASA Astrophysics Data System (ADS)

    Periáñez, Raúl; Hierro, Almudena; Bolívar, Juan Pedro; Vaca, Federico

    2013-10-01

    A numerical model to study the behavior and distribution of natural radionuclides in sediments of an estuary (Odiel and Tinto rivers, SW Spain) affected by acid mine drainage and industrial activities has been developed. The model solves water circulation due to tides and river stream flows. The dispersion model includes uptake/release reactions of radionuclides between the dissolved phase and bed sediments in a dynamic way, using kinetic transfer coefficients. Seasonal pH and chlorinity distributions are simulated, and a formulation has been developed to consider these seasonal variations on kinetic coefficients. Calculated concentrations of 226Ra and 238U in sediments have been compared with measurements from four seasonal sampling campaigns. Numerical experiments have been carried out to study the relative significance of the different radionuclides sources into the estuary as well as the effect of the two components of water circulation (tides are river flows) on radionuclide dispersion patterns.

  17. In healthy primates, circulating autoreactive T cells mediate autoimmune disease.

    PubMed Central

    Genain, C P; Lee-Parritz, D; Nguyen, M H; Massacesi, L; Joshi, N; Ferrante, R; Hoffman, K; Moseley, M; Letvin, N L; Hauser, S L

    1994-01-01

    A T cell response against myelin basic protein (MBP) is thought to contribute to the central nervous system (CNS) inflammation that occurs in the human demyelinating disease multiple sclerosis. To test whether MBP-reactive T cells that are normally retrieved from the circulation are capable of inducing CNS disease, MBP-reactive T cell clones were isolated from the peripheral blood of healthy, unimmunized Callithrix jacchus (C. jacchus) marmosets. This primate species is characterized by a natural chimerism of bone marrow elements between siblings that should make possible adoptive transfer of MBP-reactive T cells. We report that MBP-reactive T cell clones efficiently and reproducibly transfer CNS inflammatory disease between members of C. jacchus chimeric sets. The demyelination that is characteristic of experimental allergic encephalomyelitis induced in C. jacchus by immunization against human white matter did not occur after adoptive transfer of the MBP-reactive clones. It was noteworthy that encephalitogenic T cell clones were diverse in terms of their recognition of different epitopes of MBP, distinguishing the response in C. jacchus from that in some inbred rodents in which restricted recognition of MBP occurs. These findings are the first direct evidence that natural populations of circulating T cells directed against a CNS antigen can mediate an inflammatory autoimmune disease. Images PMID:7521889

  18. The Importance of Zonal Asymmetry in the Southern Hemisphere Circulation

    NASA Astrophysics Data System (ADS)

    Solomon, A. L.; Polvani, L. M.

    2015-12-01

    The atmospheric circulation in the Southern Hemisphere is considered a good example of a zonally symmetric jet, but recent papers have questioned the accuracy of this approximation. Numerous studies of the southern annular mode and the budget of zonal-mean momentum have sought to understand the timescales and causes of variability, as well as trends associated with climate change. This raises a question: when does taking the zonal mean give you the wrong answer? To address this question we employ the CESM-Large Ensemble, a 30-member, fully coupled set of simulations, suitable for assessing both the forced response and natural variability of the climate system. We find that in DJF, 20th century trends associated with the ozone hole are uniform with longitude and height, and far exceed the natural variability of the system. In contrast, the JJA circulation and its trends have a longitudinal structure that is obscured by zonal averaging. The consequence is that a significant regional deceleration of the jet stream predicted for the coming century, presumably driven by increasing concentrations of greenhouse gases, is completely eliminated in the zonal mean.

  19. Calculating drug doses.

    PubMed

    2016-09-01

    Numeracy and calculation are key skills for nurses. As nurses are directly accountable for ensuring medicines are prescribed, dispensed and administered safely, they must be able to understand and calculate drug doses. PMID:27615351

  20. 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

  1. 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.

  2. 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. PMID:21972565

  3. 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.

  4. Calculator-Active Materials.

    ERIC Educational Resources Information Center

    Crow, Tracy, Ed.; Harris, Julia, Ed.

    1997-01-01

    This journal contains brief descriptions of calculator-active materials that were found using Resource Finder, the searchable online catalog of curriculum resources from the Eisenhower National Clearinghouse (ENC). It features both the calculators themselves and the activity books that are used with them. Among the calculators included are those…

  5. Flexible Mental Calculation.

    ERIC Educational Resources Information Center

    Threlfall, John

    2002-01-01

    Suggests that strategy choice is a misleading characterization of efficient mental calculation and that teaching mental calculation methods as a whole is not conducive to flexibility. Proposes an alternative in which calculation is thought of as an interaction between noticing and knowledge. Presents an associated teaching approach to promote…

  6. Characterization of circulating transfer RNA-Derived RNA fragments in cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective was to characterize naturally occurring circulating transfer RNA-derived RNA Fragments (tRFs) in cattle. Serum from eight clinically normal adult dairy cows was collected, and small non-coding RNAs were extracted immediately after collection and sequenced by Illumina MiSeq. Sequences a...

  7. Obliquity Experiments with a Mars General Circulation Model

    NASA Technical Reports Server (NTRS)

    Harberle, R. M.; Schaeffer, J.; Cuzzi, Jeffery N. (Technical Monitor)

    1995-01-01

    We have simulated the seasonal variation of the general circulation on Mars for obliquities of 0deg and 60deg. These obliquities represent the minimum and maximum values the planet has experienced during the past 10(exp 7) years (e.g., Laskar and Robutel, 1993, Nature, 361, 608-614). The model we use is the NASA/Ames Mars General Circulation Model (Pollack et al., 1993, J. Geophys. Res. 98, 3149-3181). We vary only the obliquity; all other model parameters are as in Pollack et al. At high obliquity, the model shows dramatic seasonal variations in the polar caps and in the structure and intensity of the circulation. At the solstices the winter cap extends to the equator. Thus, surface temperatures throughout the entire winter hemisphere are fixed at the CO2 frost point. During summer surface temperatures at the poles reach 269K in the north and 295K in the south. The most notable changes to the circulation at solstice compared to our standard runs are a general weakening of the winter westerlies, a Hadley cell of greater latitudinal extent, and the development of very strong, possibly unstable, low-level jets in midlatitudes of the summer hemisphere. Surface stresses associated with these jets are sufficient to raise dust continuously. Thus, dust storms should be frequent features of the high obliquity climate. This result is independent of any desorbed regolith CO2 which would raise mean surface pressures. At zero obliquity the structure of the circulation resembles that of present day equinox conditions modulated by the varying insolation associated with orbital eccentricity. Notable features include equatorial superrotation, asymmetric Hadley cells, and stronger poleward heat fluxes in the northern hemisphere. Since the poles do not receive solar energy at any time of year, permanent caps form which extend to about 70deg in each hemisphere. However, the north permanent cap is growing at a rate 40% faster than the south cap. This is due to the differences in

  8. 46 CFR 56.50-45 - Circulating pumps.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 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....

  9. 46 CFR 56.50-45 - Circulating pumps.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 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....

  10. 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....

  11. 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....

  12. Circulation Practices and Pricing in Mid-Sized Dailies.

    ERIC Educational Resources Information Center

    Picard, Robert G.

    A study analyzed circulation practices and pricing of mid-sized daily newspapers, seeking to draw together a comprehensive description of the circulation situation for those papers. Seventy-five circulation directors, randomly selected from newspapers with daily circulation between 25,000 and 100,000, completed mailed questionnaires requesting…

  13. 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.

  14. Circulation' dynamo in complex plasma

    NASA Astrophysics Data System (ADS)

    Rubin-Zuzic, Milenko; Thomas, Hubertus M.; Zhdanov, Sergej K.; Morfill, Gregor E.

    2007-02-01

    In ground based experiments (performed in Ar using a radio frequency (rf)-discharge), we observe the interaction of individual agglomerated particles with a monodisperse (bulk) complex plasma cloud containing (melamine-formaldehyde (MF)) microparticles of 7.17 μm± 3% diameter. The particles are levitated by thermophoresis. For this purpose, a gas temperature gradient of 2000 K m-1 is applied. The particle cloud has a complicated 'sandwich-like' vertical structure of two dense slabs (filled by particles), separated by a void, a central particle-free region. The void is impenetrable for small particles, but not for heavier and/or accelerated agglomerates, which may slide through the entire void and therefore can be used as natural test particles for determination of the force acting inside the void. The bulk particles remain in quasi-equilibrium for a long time and are dynamically active, e.g., intense edge rotations (vortices) and nonlinear vertical waves. We traced particle motions in detail and studied the correlation of particle vibrations inside the clouds and the motion of agglomerates and/or accelerated particles penetrating through the void. A possible physical explanation of the cloud's activity is based on the assumption that the phenomenon can be considered as a consequence of the non-Hamiltonian character of complex plasmas.

  15. 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

  16. The Bjerknes' Circulation Theorem: A Historical Perspective.

    NASA Astrophysics Data System (ADS)

    Thorpe, Alan J.; Volkert, Hans; Ziemianski, Micha J.

    2003-04-01

    Two lines of thinking concerning fluid rotation-using either vorticity or circulation-emerged from the nineteenth-century work of Helmholtz and Thomson (Lord Kelvin), respectively. Vilhelm Bjerknes introduced an extension of Kelvin's ideas on circulation into geophysics. In this essay a historical perspective will be given on what has become known as the "Bjerknes circulation theorem." Bjerknes wrote several papers on this topic, the first being in 1898. As Bjerknes noted, a Polish physicist, Ludwik Silberstein, had previously published an equivalent result concerning vorticity generation in 1896. Silberstein's work had built on an earlier paper by J. R. Schütz in 1895. In his 1898 paper Bjerknes describes many possible applications of the theorem to meteorology and oceanography including to extratropical cyclones, a subject that made his "Bergen School" famous.

  17. 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.

  18. 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.

  19. Circulating venous bubbles in children after diving.

    PubMed

    Lemaitre, Frederic; Carturan, Daniel; Tourney-Chollet, Claire; Gardette, Bernard

    2009-02-01

    Doppler ultrasonic detection of circulating venous bubbles after a scuba dive is a useful index of decompression safety in adults, since a relationship between bubbles and the risk of decompression sickness has been documented. No study, however, has investigated circulating venous bubbles in young recreational divers after their usual dives. The aim of this study was to determine whether these bubbles would be detected in children who performed a single dive without any modification in their diving habits. Ten young recreational divers (13.1 +/- 2.3 years) performed their usual air dive. They were Doppler-monitored 20 min before the dive (12 +/- 3 m for 26 +/- 7 min) and for 60 min after surfacing, at 20-min intervals. No circulating venous bubbles were detected after the children surfaced. The results showed that during a usual shallow diving session, venous bubbles were not detected in children.

  20. Model calculation of radiocaesium transfer into food products in semi-natural forest ecosystems in the Czech Republic after a nuclear reactor accident and an estimate of the population dose burden.

    PubMed

    Svadlenková, M; Konecný, J; Smutný, V

    1996-01-01

    Radioactivity of food products from semi-natural forest ecosystems can contribute appreciably to the radiological burden of the human population following a nuclear accident, as found after the Chernobyl disaster in 1986. In the Czech Republic, radiocaesium radioactivity has been measured since 1986 in various components of forest ecosystems, such as soil, mushrooms, bilberries, deer and boar. In this work, the data are employed to predict how a model accident of the Temelín nuclear power plant in southern Bohemia (which is under construction) would affect selected forest ecosystems in its surroundings. The dose commitment to the critical population group is also estimated.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Waste Package Lifting Calculation

    SciTech Connect

    H. Marr

    2000-05-11

    The objective of this calculation is to evaluate the structural response of the waste package during the horizontal and vertical lifting operations in order to support the waste package lifting feature design. The scope of this calculation includes the evaluation of the 21 PWR UCF (pressurized water reactor uncanistered fuel) waste package, naval waste package, 5 DHLW/DOE SNF (defense high-level waste/Department of Energy spent nuclear fuel)--short waste package, and 44 BWR (boiling water reactor) UCF waste package. Procedure AP-3.12Q, Revision 0, ICN 0, calculations, is used to develop and document this calculation.

  8. Brief Exercises Affect Gene Expression in Circulating Monocytes.

    PubMed

    Wang, D; Cai, F; Ge, J; Yin, L

    2015-11-01

    We aimed to give a systematic hypothesis on the functions of exercise on circulating monocytes by identifying a discrete set of genes in circulating monocytes that were altered by exercise. The microarray expression profile of GSE51835 was downloaded from gene expression omnibus (GEO) database for the identification of differentially expressed genes (DEGs) using limma and affy packages in R language. Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed for DEGs, followed by the construction of co-expression network and protein-protein interaction (PPI) network. The top 10 nodes in PPI network were screened, and subnetwork was constructed for the key genes identification. Totally, 35 DEGs, including 2 upregulated genes and 33 downregulated genes, were identified. The enriched GO terms were mainly linked to immune response and defence response, and the enriched KEGG pathways were mainly associated with natural killer cell-mediated cytotoxicity and graft-versus-host disease. Dual-specificity phosphatase 2 (DUSP2) was identified as a key node in the co-expression network. In the PPI network, CD247 module (CD247), chemokine (C-X-C motif) receptor 4 (CXCR4), granzyme B (GZMB) and perforin 1 (PRF1) were identified as key nodes. An important interaction, GZMB/PRF1, was detected. Five key genes, including DUSP2, CD247, CXCR4, GZMB and PRF1, and an interaction of GZMB/PRF1, were significant factors in the immune processes of circulating monocytes, which might be regulated by brief exercises, leading to the enhancement of immune function.

  9. Circulating microRNA Profiles during the Bovine Oestrous Cycle.

    PubMed

    Ioannidis, Jason; Donadeu, F Xavier

    2016-01-01

    Up to 50% of ovulations go undetected in modern dairy herds due to attenuated oestrus behavior and a lack of high-accuracy methods for detection of fertile oestrus. This significantly reduces overall herd productivity and constitutes a high economic burden to the dairy industry. MicroRNAs (miRNAs) are ubiquitous regulators of gene expression during both health and disease and they have been shown to regulate different reproductive processes. Extracellular miRNAs are stable and can provide useful biomarkers of tissue function; changes in circulating miRNA profiles have been reported during menstrual cycles. This study sought to establish the potential of circulating miRNAs as biomarkers of oestrus in cattle. We collected plasma samples from 8 Holstein-Friesian heifers on days Days 0, 8 and 16 of an oestrous cycle and analysed small RNA populations on each Day using two independent high-throughput approaches, namely, Illumina sequencing (n = 24 samples) and Qiagen PCR arrays (n = 9 sample pools, 3-4 samples / pool). Subsequently, we used RT-qPCR (n = 24 samples) to validate the results of high-throughput analyses, as well as to establish the expression profiles of additional miRNAs previously reported to be differentially expressed during reproductive cycles. Overall, we identified four miRNAs (let-7f, miR-125b, miR-145 and miR-99a-5p), the plasma levels of which distinctly increased (up to 2.2-fold, P < 0.05) during oestrus (Day 0) relative to other stages of the cycle (Days 8 and 16). Moreover, we identified several hundred different isomiRs and established their relative abundance in bovine plasma. In summary, our results reveal the dynamic nature of plasma miRNAs during the oestrous cycle and provide evidence of the feasibility of using circulating miRNAs as biomarkers of reproductive function in livestock in the future. PMID:27340826

  10. Circulating microRNA Profiles during the Bovine Oestrous Cycle

    PubMed Central

    Ioannidis, Jason; Donadeu, F. Xavier

    2016-01-01

    Up to 50% of ovulations go undetected in modern dairy herds due to attenuated oestrus behavior and a lack of high-accuracy methods for detection of fertile oestrus. This significantly reduces overall herd productivity and constitutes a high economic burden to the dairy industry. MicroRNAs (miRNAs) are ubiquitous regulators of gene expression during both health and disease and they have been shown to regulate different reproductive processes. Extracellular miRNAs are stable and can provide useful biomarkers of tissue function; changes in circulating miRNA profiles have been reported during menstrual cycles. This study sought to establish the potential of circulating miRNAs as biomarkers of oestrus in cattle. We collected plasma samples from 8 Holstein-Friesian heifers on days Days 0, 8 and 16 of an oestrous cycle and analysed small RNA populations on each Day using two independent high-throughput approaches, namely, Illumina sequencing (n = 24 samples) and Qiagen PCR arrays (n = 9 sample pools, 3–4 samples / pool). Subsequently, we used RT-qPCR (n = 24 samples) to validate the results of high-throughput analyses, as well as to establish the expression profiles of additional miRNAs previously reported to be differentially expressed during reproductive cycles. Overall, we identified four miRNAs (let-7f, miR-125b, miR-145 and miR-99a-5p), the plasma levels of which distinctly increased (up to 2.2-fold, P < 0.05) during oestrus (Day 0) relative to other stages of the cycle (Days 8 and 16). Moreover, we identified several hundred different isomiRs and established their relative abundance in bovine plasma. In summary, our results reveal the dynamic nature of plasma miRNAs during the oestrous cycle and provide evidence of the feasibility of using circulating miRNAs as biomarkers of reproductive function in livestock in the future. PMID:27340826

  11. Standpipe models for diagnostics and control of a circulating fluidized bed

    SciTech Connect

    Ludlow, James C.; Panday, Rupen

    2013-01-01

    Two models for a Circulating Fluidized Bed (CFB) standpipe were formulated, implemented and validated to estimate critical CFB operational parameters. The first model continuously estimates standpipe bed height using incremental pressure measurements within the standpipe. The second model estimates variations in the void fraction along the standpipe using the Ergun equation in conjunction with the overall pressure drop across the bed, solids circulation rate and the standpipe aeration flows introduced at different locations of the pipe. The importance of different standpipe parameters obtained from these models is discussed in terms of successful operation of the overall CFB system. Finally, the applications of these models are shown in improving the solids circulation rate measurement and in calculating riser inventory.

  12. 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.

  13. 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.

  14. 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.

  15. 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. PMID:21560270

  16. 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.

  17. 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. PMID:10677463

  18. Detecting Holocene changes in thermohaline circulation

    PubMed Central

    Keigwin, L. D.; Boyle, E. A.

    2000-01-01

    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. PMID:10677463

  19. 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

  20. 3D Visualization of Global Ocean Circulation

    NASA Astrophysics Data System (ADS)

    Nelson, V. G.; Sharma, R.; Zhang, E.; Schmittner, A.; Jenny, B.

    2015-12-01

    Advanced 3D visualization techniques are seldom used to explore the dynamic behavior of ocean circulation. Streamlines are an effective method for visualization of flow, and they can be designed to clearly show the dynamic behavior of a fluidic system. We employ vector field editing and extraction software to examine the topology of velocity vector fields generated by a 3D global circulation model coupled to a one-layer atmosphere model simulating preindustrial and last glacial maximum (LGM) conditions. This results in a streamline-based visualization along multiple density isosurfaces on which we visualize points of vertical exchange and the distribution of properties such as temperature and biogeochemical tracers. Previous work involving this model examined the change in the energetics driving overturning circulation and mixing between simulations of LGM and preindustrial conditions. This visualization elucidates the relationship between locations of vertical exchange and mixing, as well as demonstrates the effects of circulation and mixing on the distribution of tracers such as carbon isotopes.

  1. 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)

  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. Programming Circulation Factors in K-12 Facilities.

    ERIC Educational Resources Information Center

    Hall, Michael E.; Fanning, Ronald H.

    This paper provides architects and educational planners with data on the necessary space requirements for restrooms, mechanical rooms, custodial spaces, food service, construction enclosure space, and circulation and corridor space, as well as an ongoing indication of necessary building area per student. It offers itemized data to illustrate…

  5. An Automated Library Circulation System: A Justification.

    ERIC Educational Resources Information Center

    Harrell, Charles B.

    This report for an automated circulation control system to replace the currently used automated off-line batch system discusses the general requirements for the requested system, the equipment needed, the planned uses and design of the proposed system, its utilization, its expected benefits, its estimated costs, the alternatives considered, and…

  6. 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…

  7. Circulation system complex networks and teleconnections

    NASA Astrophysics Data System (ADS)

    Gong, Zhi-Qiang; Wang, Xiao-Juan; Zhi, Rong; Feng, Ai-Xia

    2011-07-01

    In terms of the characteristic topology parameters of climate complex networks, the spatial connection structural complexity of the circulation system and the influence of four teleconnection patterns are quantitatively described. Results of node degrees for the Northern Hemisphere (NH) mid-high latitude (30° N-90° N) circulation system (NHS) networks with and without the Arctic Oscillations (AO), the North Atlantic Oscillations (NAO) and the Pacific—North American pattern (PNA) demonstrate that the teleconnections greatly shorten the mean shortest path length of the networks, thus being advantageous to the rapid transfer of local fluctuation information over the network and to the stability of the NHS. The impact of the AO on the NHS connection structure is most important and the impact of the NAO is the next important. The PNA is a relatively independent teleconnection, and its role in the NHS is mainly manifested in the connection between the NHS and the tropical circulation system (TRS). As to the Southern Hemisphere mid-high latitude (30° S-90° S) circulation system (SHS), the impact of the Antarctic Arctic Oscillations (AAO) on the structural stability of the system is most important. In addition, there might be a stable correlation dipole (AACD) in the SHS, which also has important influence on the structure of the SHS networks.

  8. Circulating tumor cells in colorectal cancer patients.

    PubMed

    Torino, Francesco; Bonmassar, Enzo; Bonmassar, Laura; De Vecchis, Liana; Barnabei, Agnese; Zuppi, Cecilia; Capoluongo, Ettore; Aquino, Angelo

    2013-11-01

    The availability of sensitive methods has allowed the detailed study of circulating tumor cells only recently. Evolving evidence support the prognostic and predictive role of these cells in patients affected by several solid tumors, including colorectal cancer. Ongoing studies are aimed at confirming that the molecular characterization of circulating tumor cells in peripheral blood and in bone marrow of patients is a powerful tool to improve the patient risk-stratification, to monitor activity of the drugs, to develop more appropriate targeted therapies and tailored treatments. In parallel, results from these correlative studies promise to gain a better biological understanding of the metastatic process. The clinical utility of the detection of circulating tumor cells in patients affected by colorectal cancer is still hampered by a number of specific hurdles. Improvement in sensitivity and specificity of the available methods of detection, standardization of these methods and functional characterization of circulating tumor cells in well designed and statistically well powered studies are the key steps to reach these ambitious objectives in colorectal cancer patients as well.

  9. [Circulating "tumor markers" in gastrointestinal tumors].

    PubMed

    Borlinghaus, P; Lamerz, R

    1991-09-01

    Tumor markers (TM) of the neoplastic cell can be divided into non-shedded substances and antigens shedded in blood, urine or other body fluids. For clinicians circulating TM are more important. All relevant circulating TM are not useful in screening of asymptomatic patients because of insufficient sensitivity and specificity. With caution they are useful in the observation of risk groups. Circulating TM have their main significance as additional parameters in monitoring symptomatic patients with malignancies. Several follow up determinations are more important than one single measurement. During follow up of tumor patients TM should not be checked automatically if there are no diagnostic or therapeutical consequences. The clinically most important circulating TM in non-hormone secreting tumors of the gastrointestinal tract are the oncofetal antigens CEA and AFP and antigens defined by monoclonal antibodies e. g. CA 19-9 and CA 72-4. AFP is the primary TM in hepatocellular carcinoma, often elevated in hepatoblastoma and always normal in cholangiocellular carcinoma. CEA is the TM of first choice in patients with colorectal carcinomas and liver metastasis. CA 19-9 is TM of first choice in pancreatic carcinoma and additionally of diagnostic value in cholangiocellular carcinoma and tumors of the bile ducts. In cancer of the stomach CA 19-9 and CEA are secondary TM in combination with CA 72-4 as primary TM. Care should be taken that slight and moderate elevations of TM can be observed in benign diseases of liver, pancreas and bowel.

  10. Circulation pattern classification for climate change studies

    NASA Astrophysics Data System (ADS)

    Stehlik, J.; Bardossy, A.

    2003-04-01

    Several circulation pattern classifications developed for different European regions were compared regarding their mutual dependence. Circulation pattern (CP) classifications, both subjective and objective, for the British Isles, Germany and Greece were taken into account. Statistical tests were applied in order to investigate the relationships between each pair of CP classifications. It was found that each pair of classifications can not be considered to be independent. Time dependence of the relationship between CP classifications shows anomaleous behavior only when one of the classifications is subjective. This can be due to a gradual change in the methodology. Thus, one should use these classifications for climate evolution studies with care. Results showing the inter-dependence of different CP classifications were motivation for developing one classification which would be valid in every European region. For this purpose an objective and automated classification was applied. By means of daily 700 hPa data, 13 CPs were defined which explain the variability of local precipitation in 27 stations spread over the whole of Europe. The validation of this classification proved that there is almost no information lost when comparing this classification with local classifications. Based on this classification method the air pressure outputs from Global Circulation Models will be classified. Subsequently the classified circulation patterns will be used for climate change studies. For this purpose statistical downscaling of precipitation will be applied.

  11. Variability in deep ocean circulation from GRACE

    NASA Astrophysics Data System (ADS)

    Boening, C.; Watkins, M. M.

    2015-12-01

    Although nearly impossible to observe on a global scale, total water mass transport and inter-basin exchange are central to understanding long-term changes in ocean circulation. Of particular interest are changes in the Meridional Overturning Circulation (MOC) as they pose potential impacts in continental climtae. However, in-situ observations are limited in space and time preventing a holistic view of current variability. The representation of long-term transports in ocean models is highly dependent on the atmospheric forcing fields, which may misrepresent real interannual variability. The bottom pressure observations from the Gravity Recovery And Climate Experiment (GRACE) provide for the first time the ability to observe this global water mass transport. Here, we present the first near-global maps of variability in the depth-independent ocean circulation derived from advanced analysis of GRACE data. We find that significant variability on annual to decadal time scales exists in the deep large-scale circulation, some of which are related to the Southern Annular Mode forcing dominating Southern Ocean variability.

  12. General circulation of the Jovian stratosphere

    NASA Astrophysics Data System (ADS)

    Medvedev, Alexander S.; Sethunadh, Jisesh; Hartogh, Paul

    The stratosphere of Jupiter is a convectively stable and coldest layer that extends for about 350 km above the tropopause. The dynamics of stratospheres of fast rotating gas giants differ from that of terrestrial-like planets, their modeling is more challenging, and is still little known despite a growing number of observations. We present results of simulations with a newly developed Jovian general circulation model, which covers the altitudes between one bar and one microbar. The results demonstrate a high sensitivity of the circulation to variations of eddy diffusion, which, in turn, depends on the model resolution and assumed background viscosity. In the lower stratosphere, the multiple circulation cells associated with the tropospheric alternating jets dominate. Higher, a weak two-cell equator-to-pole transport forms due to the influence of smaller-scale eddies. The strength and extent of this circulation are defined by the momentum supplied by shallow and vertically propagating waves, and are consistent with observations of the Shoemaker-Levi 9 comet traces. We will also discuss the dynamical implications of our recent finding that radiative forcing exponentially increases with height, rather than approximately constant throughout the Jovian stratosphere, as was thought before (see presentation of T. Kuroda at B0.3 session).

  13. 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…

  14. Aquifer-Circulating Water Curtain Cultivation System To Recover Groundwater Level And Temperature

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Ko, K.; Chon, C.; Oh, S.

    2011-12-01

    Groundwater temperature, which generally ranges 14 to 16 degree of Celsius all year long, can be said to be 'constant' compared to the amplitude of daily variation of air temperature or surface water. Water curtain cultivating method utilizes this 'constant' groundwater temperature to warm up the inside of greenhouse during winter night by splash groundwater on the roof of inner greenhouse. The area of water curtain cultivation system have increased up to 107.5 square kilometers as of 2006 since when it is first introduced to South Korea in 1984. Groundwater shortage problem became a great issue in a concentrated water curtain cultivation area because the pumped and splashed groundwater is abandoned to nearby stream and natural recharge rate is reduced by greenhouses. The amount of groundwater use for water curtain cultivation system in South Korea is calculated to be 587 million cubic meters which is 35% of national agricultural use of groundwater. A new water curtain cultivation system coupled with aquifer circulating of the splashed groundwater and greenhouse roof-top rainwater harvesting is developed and applied to field site in Nonsan-si, Chungnam province to minimize groundwater shortage problem and recover groundwater level. The aquifer circulating water curtain cultivation system is consist of a pumping well and a injection well of 80 m deep, groundwater transfer and splashing system, recovery tank and rainwater collecting waterway. The distance between injection and pumping well is 15 m and an observation well is installed in the middle of the wells. To characterize hydrogeological properties of this site, hydraulic test such as pumping tests and tracer tests with dye tracer, thermal tracer and ion tracer. Once the integrated system is constructed in this site, hydraulic head in all the wells and temperature of air, recovery tank and groundwater in all the wells are monitored during the operation for 3months in winter season. Hydraulic test and tracer

  15. Atmospheric Circulation Variability in the Tropics and the Northern Hemisphere During the Past 100 Years

    NASA Astrophysics Data System (ADS)

    Brönnimann, S.; Fischer, A. M.; Griesser, T.; Stickler, A.

    2009-04-01

    Documenting the variability of the large-scale atmospheric circulation during the past is important in order to better understand - and eventually predict - interannual-to-decadal climate variability. The large-scale tropical circulation features such as the Hadley and Walker cells and the monsoon systems play a particularly important role not only because of the effects within the tropics, but also because of their teleconnections to the extratropics. Here we present time series of large-scale atmospheric circulation indices back to 1900 and compare these with output from a 9-member "all forcings" ensemble calculation by a general circulation model. The indices represent the main features of the zonal mean circulation in the northern hemisphere in boreal winter (such as the Hadley circulation and the subtropical jet) as well as aspects of the regional and large-scale circulation (the Indian monsoon and the Pacific North American pattern, PNA). Back to 1948 the indices are taken from NCEP/NCAR reanalysis and are statistically reconstructed based on historical upper-air and surface data prior to 1948. We discuss the interannual-to-decadal variability of the index time series and compare them with possible driving factors, such as El Niño/Southern Oscillation, volcanic eruptions and solar activity. The results show that the interannual variability of the Hadley cell and subtropical jet is well reproduced in the model ensemble mean (and hence potentially predictable), whereas the poleward extent of the Hadley cell and the latitude of the subtropical jet are less well predictable. For all indices, the correlation between observations and model ensemble mean agree favourably well with the correlations between individual ensemble members. We find that the source of predictability is mainly related to ENSO. On the decadal scale small but significant effects of solar variability are found.

  16. [Thermoregulating devices for artificial circulation apparatus with thermoelectric elements].

    PubMed

    Efremov, A A; Andrushchenko, L I

    1981-01-01

    The increase of the absolute capacity of temperature control devices used in extracorporeal blood circulation apparatus has necessitated the intensification of heat exchange and, as a consequence, the work of heat exchangers under anisothermal conditions. This concerns mainly thermoelectric temperature control devices. Calculations in the process of their design and, to a greater extent, the optimization of their parameters under the conditions of anisothermality in the soldered joints become far more complicated. The numerical analysis of such thermoelectric device with anisothermal soldered joints has demonstrated the possibility of its analytical optimization by assuming it to be a thermoelectric device working under the average effective values of temperature and the coefficients of electrical characteristics. The results thus obtained allow to considerably decrease labor consumption in designing the above-mentioned devices. PMID:7207094

  17. Calculators and Polynomial Evaluation.

    ERIC Educational Resources Information Center

    Weaver, J. F.

    The intent of this paper is to suggest and illustrate how electronic hand-held calculators, especially non-programmable ones with limited data-storage capacity, can be used to advantage by students in one particular aspect of work with polynomial functions. The basic mathematical background upon which calculator application is built is summarized.…

  18. TI-73 Calculator Activities

    ERIC Educational Resources Information Center

    Phillips-Bey, Carol K.

    2004-01-01

    This article describes TI-73 calculator activities appropriate for middle school students. It was found that the use of the calculator allowed for higher-level thinking and a richer exploration of mathematical ideas by students. [Included with this article are "Dice Roll Worksheet" and "Transforming Tree Worksheet".] (Contains 9 figures.)

  19. The biomolecular corona of nanoparticles in circulating biological media.

    PubMed

    Pozzi, D; Caracciolo, G; Digiacomo, L; Colapicchioni, V; Palchetti, S; Capriotti, A L; Cavaliere, C; Zenezini Chiozzi, R; Puglisi, A; Laganà, A

    2015-09-01

    When nanoparticles come into contact with biological media, they are covered by a biomolecular 'corona', which confers a new identity to the particles. In all the studies reported so far nanoparticles are incubated with isolated plasma or serum that are used as a model for protein adsorption. Anyway, bodily fluids are dynamic in nature so the question arises on whether the incubation protocol, i.e. dynamic vs. static incubation, could affect the composition and structure of the biomolecular corona. Here we let multicomponent liposomes interact with fetal bovine serum (FBS) both statically and dynamically, i.e. in contact with circulating FBS (≈40 cm s(-1)). The structure and composition of the liposome-protein corona, as determined by dynamic light scattering, electrophoretic light scattering and liquid chromatography tandem mass spectrometry, were found to be dependent on the incubation protocol. Specifically, following dynamic exposure to FBS, multicomponent liposomes were less enriched in complement proteins and appreciably more enriched in apolipoproteins and acute phase proteins (e.g. alpha-1-antitrypsin and inter-alpha-trypsin inhibitor heavy chain H3) that are involved in relevant interactions between nanoparticles and living systems. Supported by our results, we speculate that efficient predictive modeling of nanoparticle behavior in vivo will require accurate knowledge of nanoparticle-specific protein fingerprints in circulating biological media.

  20. 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

  1. Blood transcriptomes reveal novel parasitic zoonoses circulating in Madagascar's lemurs.

    PubMed

    Larsen, Peter A; Hayes, Corinne E; Williams, Cathy V; Junge, Randall E; Razafindramanana, Josia; Mass, Vanessa; Rakotondrainibe, Hajanirina; Yoder, Anne D

    2016-01-01

    Zoonotic diseases are a looming threat to global populations, and nearly 75% of emerging infectious diseases can spread among wildlife, domestic animals and humans. A 'One World, One Health' perspective offers us an ideal framework for understanding and potentially mitigating the spread of zoonoses, and the island of Madagascar serves as a natural laboratory for conducting these studies. Rapid habitat degradation and climate change on the island are contributing to more frequent contact among humans, livestock and wildlife, increasing the potential for pathogen spillover events. Given Madagascar's long geographical isolation, coupled with recent and repeated introduction of agricultural and invasive species, it is likely that a number of circulating pathogens remain uncharacterized in lemur populations. Thus, it is imperative that new approaches be implemented for de novo pathogen discovery. To this end, we used non-targeted deep sequencing of blood transcriptomes from two species of critically endangered wild lemurs (Indri indri and Propithecus diadema) to characterize blood-borne pathogens. Our results show several undescribed vector-borne parasites circulating within lemurs, some of which may cause disease in wildlife, livestock and humans. We anticipate that advanced methods for de novo identification of unknown pathogens will have broad utility for characterizing other complex disease transmission systems. PMID:26814226

  2. Observations of the summer Red Sea circulation

    NASA Astrophysics Data System (ADS)

    Sofianos, Sarantis S.; Johns, William E.

    2007-06-01

    Aiming at exploring and understanding the summer circulation in the Red Sea, a cruise was conducted in the basin during the summer of 2001 involving hydrographic, meteorological, and direct current observations. The most prominent feature, characteristic of the summer circulation and exchange with the Indian Ocean, is a temperature, salinity, and oxygen minimum located around a depth of 75 m at the southern end of the basin, associated with Gulf of Aden Intermediate Water inflowing from the Gulf of Aden during the summer season as an intruding subsurface layer. Stirring and mixing with ambient waters lead to marked increases in temperature (from 16.5 to almost 33°C) and salinity (from 35.7 to more than 38 psu) in this layer by the time it reaches midbasin. The observed circulation presents a very vigorous pattern with strong variability and intense features that extend the width of the basin. A permanent cyclone, detected in the northern Red Sea, verifies previous observations and modeling studies, while in the central sector of the basin a series of very strong anticyclones were observed with maximum velocities exceeding 1 m/s. The three-layer flow pattern, representative of the summer exchange between the Red Sea and the Gulf of Aden, is observed in the strait of Bab el Mandeb. In the southern part of the basin the layer flow is characterized by strong banking of the inflows and outflows against the coasts. Both surface and intermediate water masses involved in the summer Red Sea circulation present prominent spatial variability in their characteristics, indicating that the eddy field and mixing processes play an important role in the summer Red Sea circulation.

  3. 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.

  4. The Congo basin zonal overturning circulation

    NASA Astrophysics Data System (ADS)

    Neupane, Naresh

    2016-06-01

    The Gulf of Guinea in the equatorial Atlantic is characterized by the presence of strong subsidence at certain times of the year. This subsidence appears in June and becomes well established from July to September. Since much of theWest African monsoon flow originates over the Gulf, Guinean subsidence is important for determining moisture sources for the monsoon. Using reanalysis products, I contribute to a physical understanding of what causes this seasonal subsidence, and how it relates to precipitation distributions across West Africa. There is a seasonal zonal overturning circulation above the Congo basin and the Gulf of Guinea in the ERA-Interim, ERA-40, NCEP2, and MERRA reanalyses. The up-branch is located in the Congo basin around 20°E. Mid-tropospheric easterly flows constitute the returning-branch and sinking over the Gulf of Guinea forms the down-branch, which diverges at 2°W near the surface, with winds to the east flowing eastward to complete the circulation. This circulation is driven by surface temperature differences between the eastern Gulf and Congo basin. Land temperatures remain almost uniform, around 298 K, throughout a year, but the Guinean temperatures cool rapidly from 294 K in May to about 290 K in August. These temperature changes increase the ocean/land temperature contrast, up to 8 K, and drive the circulation. I hypothesize that when the overturning circulation is anomalously strong, the northward moisture transport and Sahelian precipitation are also strong. This hypothesis is supported by ERA-Interim and PERSIANN-CDR (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record) data.

  5. Circulation factors affecting precipitation over Bulgaria

    NASA Astrophysics Data System (ADS)

    Nojarov, Peter

    2015-09-01

    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.

  6. Relativistic shell model calculations

    NASA Astrophysics Data System (ADS)

    Furnstahl, R. J.

    1986-06-01

    Shell model calculations are discussed in the context of a relativistic model of nuclear structure based on renormalizable quantum field theories of mesons and baryons (quantum hadrodynamics). The relativistic Hartree approximation to the full field theory, with parameters determined from bulk properties of nuclear matter, predicts a shell structure in finite nuclei. Particle-hole excitations in finite nuclei are described in an RPA calculation based on this QHD ground state. The particle-hole interaction is prescribed by the Hartree ground state, with no additional parameters. Meson retardation is neglected in deriving the RPA equations, but it is found to have negligible effects on low-lying states. The full Dirac matrix structure is maintained throughout the calculation; no nonrelativistic reductions are made. Despite sensitive cancellations in the ground state calculation, reasonable excitation spectra are obtained for light nuclei. The effects of including charged mesons, problems with heavy nuclei, and prospects for improved and extended calculations are discussed.

  7. 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.

  8. Impact of atmospheric feedbacks on the stability of the thermohaline circulation in the Atlantic ocean

    NASA Astrophysics Data System (ADS)

    Cimatoribus, Andrea; Drijfhout, Sybren; Dijkstra, Henk

    2010-05-01

    How do atmospheric feedbacks affect the stability of thermohaline circulation in the Atlantic ocean? This question has been asked several times in literature during the last decade, but no final answer is widely accepted. Idealised and simpler general circulation models apparently contradict the results of state of the art computations. While the former ones hint at the existence of a stable collapsed state and multiple equilibria, the latter do not show such behaviour. Understanding the relative importance of the salt advection feedback in the ocean and of the response of the atmosphere to a thermohaline circulation depression is a crucial point in this work. A combined approach is developed to start answering these questions, focusing on the physical mechanisms that may change the stability properties of density driven circulation. An atmosphere/ocean/sea-ice coupled general circulation model (Speedo/CLIO) is used in two different setups. First, the statistical steady state of the model is recorded. In a second experiment, a collapse of thermohaline circulation is induced with a freshwater pulse in the north Atlantic. Thermohaline circulation does not recover even after the release of the pulse, and a second steady state with no thermohaline circulation is attained. Using these two runs, the anomalies can be computed as linear regressions on the local value of sea surface temperature and on northern hemisphere average sea surface temperature separately. With this approach, both natural variability of atmospheric forcing due to local temperature anomalies and large scale changes due to the collapse of thermohaline circulation can be represented. Changes in freshwater and heat fluxes are the most significant. The northern-southern Atlantic temperature dipole and the southward shift of intertropical convergence zone, believed to be the main atmospheric signals in response to a collapse of thermohaline circulation, are evident in the second experiment and well

  9. 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.

  10. [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.

  11. 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.

  12. Dose Calculation Spreadsheet

    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 atmore » various downwind distances as specified by the user.« less

  13. The influence of transmeridian flight on human circulating lymphocytes.

    PubMed

    Ohkoshi, H; Asukata, I; Tajima, N; Yamamoto, K; Sasaki, M; Hokari, M; Sakai, T

    1991-01-01

    We studied the influence of transmeridian flight on the number of circulating lymphocytes, which have a circadian rhythm with low values in the daytime. The number of T lymphocytes was found to be higher than the baseline value, yet its rhythmicity was maintained after eastward flight with an 8-h time difference. The number of OKB2+ as well as Leu11+ cells were suppressed after the flight. The change in the number of T lymphocytes occurred due to the increased number of OKT4+ lymphocytes. There was no correlation between the number of OKT4+ lymphocytes and the plasma cortisol level, though plasma cortisol is a major factor in regulating the number of lymphocytes. These data showed that the number of helper/inducer T lymphocytes, B cells, and natural killer cells were affected by the physical conditions experienced after the flight. The changes in T lymphocytes were independent of those of plasma cortisol levels.

  14. (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.

  15. [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".

  16. [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.

  17. 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.

  18. 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.

  19. Stress-induced changes of circulating neuropeptide Y in the rat: comparison with catecholamines.

    PubMed

    Castagné, V; Corder, R; Gaillard, R; Mormède, P

    1987-10-01

    Circulating concentrations of neuropeptide Y-like immunoreactivity (NPY), noradrenaline (NA) and adrenaline (AD) were measured in conscious, chronically catheterized rats submitted to various stress protocols. Basal plasma levels of NPY, NA and AD (194 +/- 52 fmol/ml, 0.90 +/- 0.11 pmol/ml and 0.52 +/- 0.07 pmol/ml) were increased by handling (+132%, +76% and +629%, respectively) and rose further during electric shock treatment. Adrenalectomy resulted in the complete disappearance of circulating adrenaline but did not alter either control or stress values of noradrenaline. In comparison circulating levels of NPY were reduced, but not significantly in adrenalectomized animals. Insulin stress induced a large increase in plasma AD levels and cold stress induced an increase in plasma NA levels, without any parallel change in NPY concentrations. These results demonstrate that NPY, which is colocalized with catecholamines in the peripheral nervous systems, is also released during stress responses and that its release parallels more closely changes in circulating NA than AD. Furthermore, stress-induced changes in circulating NPY-like immunoreactivity do not originate from the adrenal gland but mainly from the peripheral nervous system, and the release of NPY is dependent upon the nature of the stimulus. PMID:3317527

  20. 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. PMID:23151588

  1. 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

  2. Warm World Ocean Thermohaline Circulation Model

    NASA Astrophysics Data System (ADS)

    Zimov, N.; Zimov, S. A.

    2014-12-01

    Modern day ocean circulation is dominated by thermal convection with cold waters subsiding in the Northern Atlantic, filling the ocean interior with cold and heavy water. However, ocean circulation diminished during the last glaciation and consequently the downwelling of the cold. Therefore interior ocean water temperatures must have been affected by other mechanisms which are negligible in the current state. We propose that the submergence of highly saline water from warm seas with high rates of evaporation (like the Red or Mediterranean Sea) was a major factor controlling ocean circulation during the last glaciation. Even today, waters in these poorly connected seas are the heaviest waters in the World ocean (1.029 g/cm3). The second mechanism affecting ocean temperature is the geothermal heat flux. With no heat exchange between the atmosphere and the ocean, geothermal heat flux through the ocean floor is capable of increasing ocean temperature by tens of degrees C over a 100 thousand year glacial cycle. To support these hypotheses we present an ocean box model that describes thermohaline circulation in the World Ocean. According to the model parameters, all water circulation is driven by the water density gradient. Boxes include high-latitude seas, high salinity seas, surface ocean, glaciers, and rift and lateral zones of the ocean interior. External heat sources are radiative forcing, affected by Milankovich cycles, and geothermal heat flux. Additionally this model accounts for the heat produced by organic rain decay. Taking all input parameters close to currently observed values, the model manages to recreate the glacial-interglacial cycles. During the glacial periods only haline circulation takes place, the ocean is strongly stratified, and the interior ocean accumulates heat while high-latitudes accumulate ice. 112,000 years after glaciation starts, water density on the ocean bottom becomes equal to the density of water in high-latitude seas, strong thermal

  3. 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

  4. Target Heart Rate Calculator

    MedlinePlus

    ... My Saved Articles » My ACS » + - Text Size Target Heart Rate Calculator Compute your best workout Enter your age ... is your age? years. How to Check Your Heart Rate Right after you stop exercising, take your pulse: ...

  5. The CIPW Normative Calculation.

    ERIC Educational Resources Information Center

    Bickel, Charles

    1979-01-01

    The author has rewritten rules for CIPW norm calculation and has written FORTRAN IV programs to assist the student in this procedure. Includes a set of problems utilizing the CIPW norm to illustrate principles of chemical petrology. (MA)

  6. Alcohol Calorie Calculator

    MedlinePlus

    ... Alcohol Calorie Calculator Find out the number of beer and hard alcohol calories you are consuming. Simply ... calories) Average Drinks Per Week Monthly Subtotal Calories Beer Regular 12 149 Regular Beer Light 12 110 ...

  7. 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...

  8. 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)

  9. 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.

  10. 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.

  11. Systematics and limit calculations

    SciTech Connect

    Fisher, Wade; /Fermilab

    2006-12-01

    This note discusses the estimation of systematic uncertainties and their incorporation into upper limit calculations. Two different approaches to reducing systematics and their degrading impact on upper limits are introduced. An improved {chi}{sup 2} function is defined which is useful in comparing Poisson distributed data with models marginalized by systematic uncertainties. Also, a technique using profile likelihoods is introduced which provides a means of constraining the degrading impact of systematic uncertainties on limit calculations.

  12. 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

  13. IN SITU FLOW METERS AROUND A GROUNDWATER CIRCULATION WELL (PAPER)

    EPA Science Inventory

    The primary benefit of groundwater circulation well (GCW) technology is the development of strong vertical flows surrounding the treatment well. The extent of significant vertical flow surrounding a circulation well is difficult to establish from traditional groundwater elevation...

  14. IN SITU FLOW METERS AROUND A GROUNDWATER CIRCULATION WELL (ABSTRACT)

    EPA Science Inventory

    The primary benefit of groundwater circulation well (GCW) technology is the development of strong vertical flows surrounding the treatment well. The extent of significant vertical flow surrounding a circulation well is difficult to establish from traditional groundwater elevation...

  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. Estimated rate of thromboxane secretion into the circulation of normal humans.

    PubMed Central

    Patrono, C; Ciabattoni, G; Pugliese, F; Pierucci, A; Blair, I A; FitzGerald, G A

    1986-01-01

    We have measured the excretion of a major urinary metabolite of thromboxane B2 (TxB2), i.e., 2,3-dinor-TxB2, during the infusion of exogenous TxB2 over a 50-fold dose range to enable estimation of the rate entry of endogenous TxB2 into the bloodstream. Four healthy male volunteers received 6-h i.v. infusions of venhicle alone and TxB2 at 0.1, 1.0, and 5.0 ng/kg X min in random order. They were pretreated with aspirin at a dose of 325 mg/d in order to suppress endogenous TxB2 production. Urinary 2,3-dinor-TxB2 was measured before, during, and up to 24 h after the infusions and in aspirin-free periods, by means of radioimmunoassay. The nature of the extracted immunoreactivity was characterized by thin-layer chromatography and confirmed by negative ion-chemical ionization gas chromatography/mass spectrometry. Aspirin treatment suppressed urinary 2,3-dinor-TxB2 excretion by 80%. The fractional elimination of 2,3-dinor-TxB2 was independent of the rate of TxB2 infusion and averaged 5.3 +/- 0.8%. Interpolation of metabolite values obtained in aspirin-free periods onto the linear relationship between the quantities of infused TxB2 and the amount of metabolite excreted in excess of control values (y = 0.0066x, r = 0.975, P less than 0.001) permitted calculation of the mean rate of entry of endogenous TxB2 into the circulation as 0.11 ng/kg X min. The rate of disappearance of immunoreactive TxB2 from the circulation was monoexponential over the first 10 min with an apparent half-life of 7 min. This corresponded to a maximal estimate of the plasma concentration of endogenous TxB2 of 2.0 pg/ml. These results suggest that ex vivo platelet activation and/or analytical problems confound estimates of endogenous thromboxane release based on plasma TxB2 and provide a rationale for seeking longer-lived enzymatic metabolites of TxB2 in plasma. PMID:3944270

  17. 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.

  18. Paraplegic pressure sore frequency versus circulation measurements.

    PubMed

    Bennett, L; Lee, B Y

    1990-01-01

    Paraplegic subjects (N = 34) were examined to determine the association of pressure sore history with respect to ankle pressure ratio and buttocks cutaneous plethysmographic harmonic persistence. No relationship was found between pressure sore history and ankle pressure ratio. No significant difference in ankle pressure ratios exists for those who have a pressure sore history as compared to those who have not experienced a pressure sore in 5 years. Those subjects with a diminished buttocks circulation harmonic persistence are more likely to have experienced one or more pressure sores than those subjects with normal circulation characteristics. A Poisson distribution analysis of multiple pressure sore occurrence suggests that repeated pressure sores are unlikely to arise as the result of chance.

  19. Cognitive problems related to vertebrobasilar circulation.

    PubMed

    Koçer, Abdulkadir

    2015-01-01

    Neurodegenerative disorders are characterized by decreased regional cerebral blood flow. Supporting this concept, both cognitive training exercises and physical activity promote blood flow increase and correlate with healthy cognitive aging. The terminal branches of the posterior circulation supply blood to areas of the brain, such as the thalamus, hippocampus, occipital lobe, and cerebellum, involved with important intellectual functions, particularly recent memory, visual-spatial functioning, and visuomotor adaptations. Amnesia and visual agnosia may be a complication of not only posterior circulation infarctions but also vertebrobasilar insufficiency (VBI) without accompanying structural infarcts. The cognitive impairment maybe a manifestation of transient attacks and may persist beyond resolution of symptoms related to ischemia. Early recognition of cognitive deficits in the VBI patient is important because several recent reports show stent placements or medical treatment may improve cognition. PMID:26738337

  20. 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.

  1. 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.

  2. Circulating transportation orbits between earth and Mars

    NASA Technical Reports Server (NTRS)

    Friedlander, A. L.; Niehoff, J. C.; Byrnes, D. V.; Longuski, J. M.

    1986-01-01

    This paper describes the basic characteristics of circulating (cyclical) orbit design as applied to round-trip transportation of crew and materials between earth and Mars in support of a sustained manned Mars Surface Base. The two main types of nonstopover circulating trajectories are the socalled VISIT orbits and the Up/Down Escalator orbits. Access to the large transportation facilities placed in these orbits is by way of taxi vehicles using hyperbolic rendezvous techniques during the successive encounters with earth and Mars. Specific examples of real trajectory data are presented in explanation of flight times, encounter frequency, hyperbolic velocities, closest approach distances, and Delta V maneuver requirements in both interplanetary and planetocentric space.

  3. 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

  4. 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.

  5. Genetically Encoded Voltage Indicators in Circulation Research.

    PubMed

    Kaestner, Lars; Tian, Qinghai; Kaiser, Elisabeth; Xian, Wenying; Müller, Andreas; Oberhofer, Martin; Ruppenthal, Sandra; Sinnecker, Daniel; Tsutsui, Hidekazu; Miyawaki, Atsushi; Moretti, Alessandra; Lipp, Peter

    2015-09-08

    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.

  6. [William Harvey, discoverer of the blood circulation].

    PubMed

    v Mühlendahl, K E

    2007-06-01

    William Harvey (1578-1657), living at the turn to modern times, scientifically speaking, was an eminent physician and scientist. He developed the concept of the circulation of the blood and his findings have proved to be correct in nearly all details to this day. He published his physiological findings and interpretations in a small, albeit epoch-making, volume: Exercitatio anatomica de motu cordis et sanguinis in animalibus, published in Frankfurt in 1628. On the occasion of the 350th anniversary of his death on June 3, 2007, this essay commemorates the work of this important physician, illustrating his brilliant conception of the blood circulation by quoting passages from De motu cordis et sanguinis.

  7. Anticoagulation management associated with extracorporeal circulation.

    PubMed

    Sniecinski, Roman M; Levy, Jerrold H

    2015-06-01

    The use of extracorporeal circulation requires anticoagulation to maintain blood fluidity throughout the circuit, and to prevent thrombotic complications. Additionally, adequate suppression of hemostatic activation avoids the unnecessary consumption of coagulation factors caused by the contact of blood with foreign surfaces. Cardiopulmonary bypass represents the greatest challenge in this regard, necessitating profound levels of anticoagulation during its conduct, but also quick, efficient reversal of this state once the surgical procedure is completed. Although extracorporeal circulation has been around for more than half a century, many questions remain regarding how to best achieve anticoagulation for it. Although unfractionated heparin is the predominant agent used for cardiopulmonary bypass, the amount required and how best to monitor its effects are still unresolved. This review discusses the use of heparin, novel anticoagulants, and the monitoring of anticoagulation during the conduct of cardiopulmonary bypass.

  8. Estimates of the stratospheric residual circulation using the downward control principle

    SciTech Connect

    Rosenlof, K.H.; Holton, J.R.

    1993-06-20

    The transformed Eulerian-mean momentum and continuity equations are used to calculate the residual mean meridional circulations for the lower stratosphere and troposphere. Momentum and temperature fluxes required for the computation are estimated from U.K. Meterological Office (UKMO) analyzed geopotential heights. National Center for Atmospheric Research (NCAR) CCM2 model output is used to assess the errors associated with the calculation. The model comparisons showed that the method works reasonably well for solstice seasons, but is inadequate for equinox seasons. In addition, it is found that some parameterization of gravity wave drag needs to be included with the planetary wave forcing to accurately estimate the residual mean circulation using this method. 24 refs., 10 figs., 5 tabs.

  9. Near-surface circulation in the South China Sea during the winter monsoon

    NASA Astrophysics Data System (ADS)

    Centurioni, L. R.; Niiler, P. N.; Lee, D.-K.

    2009-03-01

    Original velocity measurements at 15 m depth from Surface Velocity Program drifters are used to calculate the circulation in the South China Sea during the Winter Monsoon. The Ekman currents are computed with a new method and subtracted from drifter's velocity to calculate the residual circulation, which is approximately in geostrophic balance. The Ekman flow is nearly zonal and comparable to the zonal geostrophic flow in the northern basin. The geostrophic flow is cyclonic and extends into the southern Luzon Strait. Strong jets occur south of Hainan, off Vietnam and, to the south, off peninsular Malaysia. The Vietnam jet is concentrated inshore of the 200 m isobath, with mean speeds in excess of 1 m s-1. The onshore Ekman transport and pumping velocity computed from the wind stress curl offer a qualitative explanation of the existence and behavior of such jets.

  10. Influence of geomagnetic disturbance on atmospheric circulation

    NASA Technical Reports Server (NTRS)

    Kodera, K.

    1985-01-01

    The influence of geomagnetic disturbance or passage of the solar sector boundary on the atmospheric circulation was reported. Unfortunately little is known about the general morphology of Sun weather relationships. In order to know the general characteristics, pressure height variations on an isobaric surface over the Northern Hemisphere were analyzed. Although it may be suitable to use some index, or some integrated value for statistical purposes, weather prediction data were used to verify whether the obtained tropospheric response is caused externally or not.

  11. Positive Stop For Circulation-Control Slot

    NASA Technical Reports Server (NTRS)

    Hunter, David; Cullen, Laurence

    1992-01-01

    Rounded shoulder on bushing ensures repeatable stop position. Improved stop mechanism allows airflow slot on circulation-control airfoil to be limited to precise width. Shoulder bushing installed in duct so shoulder rests on inside surface of duct. Bolt slides in bushing in duct wall between more open and less open positions. No relative motion or wear between bolt and slot panel. Prevents bushing from being dislodged by stop forces and provides stiffer stopping surface than sleeve bushing bonded in duct wall.

  12. Cluster Dynamics in a Circulating Fluidized Bed

    SciTech Connect

    Guenther, C.P.; Breault, R.W.

    2006-11-01

    A common hydrodynamic feature in industrial scale circulating fluidized beds is the presence of clusters. The continuous formation and destruction of clusters strongly influences particle hold-up, pressure drop, heat transfer at the wall, and mixing. In this paper fiber optic data is analyzed using discrete wavelet analysis to characterize the dynamic behavior of clusters. Five radial positions at three different axial locations under five different operating were analyzed using discrete wavelets. Results are summarized with respect to cluster size and frequency.

  13. Reconfigurable Josephson Circulator/Directional Amplifier

    NASA Astrophysics Data System (ADS)

    Sliwa, K. M.; Hatridge, M.; Narla, A.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Devoret, M. H.

    2015-10-01

    Circulators and directional amplifiers are crucial nonreciprocal signal routing and processing components involved in microwave read-out chains for a variety of applications. They are particularly important in the field of superconducting quantum information, where the devices also need to have minimal photon losses to preserve the quantum coherence of signals. Conventional commercial implementations of each device suffer from losses and are built from very different physical principles, which has led to separate strategies for the construction of their quantum-limited versions. However, as recently theoretically, by establishing simultaneous pairwise conversion and/or gain processes between three modes of a Josephson-junction-based superconducting microwave circuit, it is possible to endow the circuit with the functions of either a phase-preserving directional amplifier or a circulator. Here, we experimentally demonstrate these two modes of operation of the same circuit. Furthermore, in the directional amplifier mode, we show that the noise performance is comparable to standard nondirectional superconducting amplifiers, while in the circulator mode, we show that the sense of circulation is fully reversible. Our device is far simpler in both modes of operation than previous proposals and implementations, requiring only three microwave pumps. It offers the advantage of flexibility, as it can dynamically switch between modes of operation as its pump conditions are changed. Moreover, by demonstrating that a single three-wave process yields nonreciprocal devices with reconfigurable functions, our work breaks the ground for the development of future, more complex directional circuits, and has excellent prospects for on-chip integration.

  14. Reducing mode circulating fluid bed combustion

    DOEpatents

    Lin, Yung-Yi; Sadhukhan, Pasupati; Fraley, Lowell D.; Hsiao, Keh-Hsien

    1986-01-01

    A method for combustion of sulfur-containing fuel in a circulating fluid bed combustion system wherein the fuel is burned in a primary combustion zone under reducing conditions and sulfur captured as alkaline sulfide. The reducing gas formed is oxidized to combustion gas which is then separated from solids containing alkaline sulfide. The separated solids are then oxidized and recycled to the primary combustion zone.

  15. 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)

  16. Rotor blade construction for circulation control aircraft

    NASA Technical Reports Server (NTRS)

    Carter, Sr., Donald R. (Inventor); Krauss, Timothy A. (Inventor); Sedlak, Matthew (Inventor)

    1986-01-01

    A circulation control aircraft rotor blade having a spanwise Coanda surface 16 and a plurality of spanwise extending flexible composite material panels 18 cooperating with the surface to define slots for the discharge of compressed air from within the blade with each panel having first flexure means 60 associated with screw adjustments 36 for establishing a slot opening preload and second flexure means 62 associated with screw adjustments 38 for establishing a slot maximum opening.

  17. 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,...

  18. Comparative analysis of the North Atlantic surface circulation reproduced by three different methods

    NASA Astrophysics Data System (ADS)

    Lebedev, K. V.; Sarkisyan, A. S.; Nikitin, O. P.

    2016-07-01

    Calculation results are presented for long-term mean annual surface currents in the North Atlantic based on direct drifter measurements and numerical experiments with the ocean general circulation model using both climatic arrays of hydrological data World Ocean Atlas 2009 and Argo profiling data. The calculations show that the technique suggested for model calculations of oceanographic characteristics of the World Ocean with the use of Argo data significantly improves the climatic fields of the temperature and salinity even on a coarse grid. The comparison of the model calculation results with drifter data showed that the temperature and salinity fields found from Argo data with the use of data variational interpolation on a regular grid allow the calculation of realistic currents and can be successfully used as initial conditions in hydrodynamic models of the ocean dynamics.

  19. The Patos Lagoon summertime circulation and dynamics

    NASA Astrophysics Data System (ADS)

    Moller, Osmar O.; Lorenzzentti, Joa˜o. A.; Stech, JoséL.; Math, Mauricio M.

    1996-03-01

    The main aspects of the summertime circulation and dynamics of the Patos Lagoon, a system located in southern Brazil and considered as one of the world's largest choked coastal lagoons, are studied through the analysis of time series of wind stress, water level and freshwater discharge, combined with the results of a barotropic circulation model. The longitudinal wind component has been verified as the main driving force, generating a set-up/set-down mechanism of oscillation with the nodal line in the midlagoon area. The period of this oscillation coincides with the passages of frontal systems for this region. The sea breeze acts as a secondary effect, being clearly observed in the northern part of the lagoon. Freshwater discharge is expected to cause variations in water level on the seasonal band and to a lesser degree in the 8-15 day time-scale. The tidal signal is of importance only near the exit to the ocean, being strongly reduced in the interior of the lagoon. Model results suggest a wind set-up momentum balance in the longitudinal direction in the deeper parts of the lagoon; near the margins, the longitudinal momentum balance is mostly of frictional form, with the wind stress being balanced by the bottom friction. In the lateral direction, a geostrophic balance is verified in both regions. The wind forced circulation is characterized by the presence of several cells with downwind velocity near the margins and upwind return flow occurring in the central areas.

  20. [Circulating nucleic acids and in vitro fertilization].

    PubMed

    Scalici, E; Traver, S; Mullet, T; Ferrières, A; Monforte, M; Vintejoux, E; Hamamah, S

    2014-10-01

    During the last years, the use of circulating nucleic acids (microRNAs and cell-free DNA) as diagnostic and/or prognostic tools in cancerology was widely documented. Likewise, in obstetrics and gynecology, the development of non-invasive prenatal testing based on the assessment of these biomarkers confirmed their growing interest in this speciality. In human reproduction, several studies were interested in the microRNAs, small non-coding RNA sequences, present in the ovarian follicle and their implication in folliculogenesis. Some of these microRNAs, as well as the vesicles which transport them, are easily detectable in the bloodstream and could be used as reliable biomarkers of interest in infertility care. Cell-free DNA level varies according to physiopathology and reflect the proportion of apoptotic and/or necrotic events occurring in the body. As a result, its quantification could give an additional help to the practitioners for ovarian functional status evaluation. Furthermore, these circulating nucleic acids could also constitute new predictive biomarkers of oocyte and/or embryo quality and represent a promising perspective for the prevention of in vitro fertilization implantation failures. In conclusion, these circulating nucleic acids open the way to the development of new diagnostic and/or prognostic innovative tests in order to improve in vitro fertilization outcomes.