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Sample records for exchange parameters contribute

  1. Optimization of parameters of heat exchangers vehicles

    Directory of Open Access Journals (Sweden)

    Andrei MELEKHIN

    2014-09-01

    Full Text Available The relevance of the topic due to the decision of problems of the economy of resources in heating systems of vehicles. To solve this problem we have developed an integrated method of research, which allows to solve tasks on optimization of parameters of heat exchangers vehicles. This method decides multicriteria optimization problem with the program nonlinear optimization on the basis of software with the introduction of an array of temperatures obtained using thermography. The authors have developed a mathematical model of process of heat exchange in heat exchange surfaces of apparatuses with the solution of multicriteria optimization problem and check its adequacy to the experimental stand in the visualization of thermal fields, an optimal range of managed parameters influencing the process of heat exchange with minimal metal consumption and the maximum heat output fin heat exchanger, the regularities of heat exchange process with getting generalizing dependencies distribution of temperature on the heat-release surface of the heat exchanger vehicles, defined convergence of the results of research in the calculation on the basis of theoretical dependencies and solving mathematical model.

  2. Gas exchange and chlorophyll a fluorescence parameters of ornamental bromeliads

    Directory of Open Access Journals (Sweden)

    Karina Gonçalves da Silva

    2017-10-01

    Full Text Available Gas exchange and chlorophyll a fluorescence are widely used in physiological and ecological studies; however, few studies have used these techniques with ornamental plants. This study tested the potential contribution of gas exchange and chlorophyll a fluorescence to evaluate the water and nutrients uptake by the tank and root system of epiphyte bromeliad Guzmania lingulata. For this purpose, we conducted an experiment with different water regime and another with different concentrations of nitrogen. The experiments were: 1 - Watering: Control (application of water into Tank and Root, Tank (watering into Tank, Root (watering Root and Drought (water suspension during the 90 days of experimentation and 2 - Nitrogen: Plants fertilized with Hoagland and Arnon nutrient solution exclusively into Tank or Root with nitrogen concentrations of control and 2.62 or 5.34 mM N applied as urea. The Fv /Fm ratio allowed comparing the treatments between experiments, demonstrating that Root and Tank both have the capacity to maintain G. lingulata photosynthetic activity and growth, while Drought treatment (water suspension was the limiting factor for energy conversion efficiency of PSII. However, gas exchange was more permissive as a parameter for comparing treatments in the nitrogen experiment, providing important information about the general aspects of the photosynthetic process in the watering experiment. Both gas exchange and chlorophyll a fluorescence can support the evaluation of G. lingulata physiological status and can be useful tools in ornamental horticultural studies.

  3. Assessment of the exchange parameters of Amberlite IR-45 (OH ...

    African Journals Online (AJOL)

    CLEMENT O BEWAJI

    ABSTRACT: Simple quantitative technique has been developed for assessing the exchange parameters of Amberlite IR. – 45 (OH) using column chromatographic techniques from the displacement of exchangeable hydroxyl ions of the resin by sulphate ions. The results obtained showed retention time of 33min, retention ...

  4. Assessment of the exchange parameters of Amberlite IR-45 (OH ...

    African Journals Online (AJOL)

    Simple quantitative technique has been developed for assessing the exchange parameters of Amberlite IR – 45 (OH) using column chromatographic techniques from the displacement of exchangeable hydroxyl ions of the resin by sulphate ions. The results obtained showed retention time of 33min, retention volume of ...

  5. Optimum design parameters of a heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Bayram; Yakut, Kenan; Kotcioglu, Isak [Ataturk Univ., Dept. of Mechanical Engineering, Erzurum (Turkey); Celik, Cafer [Ataturk Univ., Dept. of Industrial Engineering, Erzurum (Turkey)

    2005-09-01

    In this study, the effects of the longitudinal and lateral separations of consecutively enlarged-contracted arranged fin pairs, widths of the fins, angle of attack, heights of fins and flow velocity on the heat and pressure drop characteristics were investigated using the Taguchi experimental-design method. Nusselt number and friction factor were considered as performance parameters. An L{sub 18}(2{sup 1}*3{sup 7}) orthogonal array was selected as an experimental plan for the eight parameters mentioned above. First of all, each goal was optimized, separately. Then, all the goals were optimized together, considering the priority of the goals, and the optimum results were found to be fin width of 15 mm, angle of attack of 15 deg, fin height of 100 mm, span-wise distance between fins of 20 mm, stream-wise distance between fins of 10 mm, span-wise distance between slices of 20 mm, stream-wise distances between slices of 20 mm at a flow velocity of 4 m/s. (Author)

  6. The solution of private problems for optimization heat exchangers parameters

    Science.gov (United States)

    Melekhin, A.

    2017-11-01

    The relevance of the topic due to the decision of problems of the economy of resources in heating systems of buildings. To solve this problem we have developed an integrated method of research which allows solving tasks on optimization of parameters of heat exchangers. This method decides multicriteria optimization problem with the program nonlinear optimization on the basis of software with the introduction of an array of temperatures obtained using thermography. The author have developed a mathematical model of process of heat exchange in heat exchange surfaces of apparatuses with the solution of multicriteria optimization problem and check its adequacy to the experimental stand in the visualization of thermal fields, an optimal range of managed parameters influencing the process of heat exchange with minimal metal consumption and the maximum heat output fin heat exchanger, the regularities of heat exchange process with getting generalizing dependencies distribution of temperature on the heat-release surface of the heat exchanger vehicles, defined convergence of the results of research in the calculation on the basis of theoretical dependencies and solving mathematical model.

  7. Contribution of calcium oxalate to soil-exchangeable calcium

    Science.gov (United States)

    Dauer, Jenny M.; Perakis, Steven S.

    2013-01-01

    Acid deposition and repeated biomass harvest have decreased soil calcium (Ca) availability in many temperate forests worldwide, yet existing methods for assessing available soil Ca do not fully characterize soil Ca forms. To account for discrepancies in ecosystem Ca budgets, it has been hypothesized that the highly insoluble biomineral Ca oxalate might represent an additional soil Ca pool that is not detected in standard measures of soil-exchangeable Ca. We asked whether several standard method extractants for soil-exchangeable Ca could also access Ca held in Ca oxalate crystals using spike recovery tests in both pure solutions and soil extractions. In solutions of the extractants ammonium chloride, ammonium acetate, and barium chloride, we observed 2% to 104% dissolution of Ca oxalate crystals, with dissolution increasing with both solution molarity and ionic potential of cation extractant. In spike recovery tests using a low-Ca soil, we estimate that 1 M ammonium acetate extraction dissolved sufficient Ca oxalate to contribute an additional 52% to standard measurements of soil-exchangeable Ca. However, in a high-Ca soil, the amount of Ca oxalate spike that would dissolve in 1 M ammonium acetate extraction was difficult to detect against the large pool of exchangeable Ca. We conclude that Ca oxalate can contribute substantially to standard estimates of soil-exchangeable Ca in acid forest soils with low soil-exchangeable Ca. Consequently, measures of exchangeable Ca are unlikely to fully resolve discrepancies in ecosystem Ca mass balance unless the contribution of Ca oxalate to exchangeable Ca is also assessed.

  8. Characterization of energy exchange parameters in the Himalayan foothills Pakistan

    Science.gov (United States)

    Khalid, Bushra; Kumar, Mukul; Cholaw, Bueh; Aziz Khan, Junaid; Hayat Khan, Azmat

    2017-04-01

    The characterization of energy exchange parameters for spring season (April-May) has been done for Margalla hills national park (MHNP) Islamabad, Pakistan. It is important because Islamabad city lies in the foothills of Himalayas and micro meteorological activity makes the climate of surrounding areas. The activity on Himalaya's foothills (i.e., Margalla hills) regulate weather and also provide fresh water to the lakes and ponds by late afternoon thunder showers. This research is also important from the perspective of rain water harvesting in Islamabad, Pakistan. The objective of this study is to characterize the energy exchange parameters in the foothills of great Himalayas particularly on MHNP. Landsat ETM+ imageries have been used for calculating the land surface temperature (LST), normalized difference vegetation index (NDVI), and normalized difference moisture index (NDMI). SPOT 5 image has been used for land use/land cover classification over MHNP. The turbulent fluxes have been calculated by computing the values acquired from the processing of satellite imageries and real time observation data sets. The comparisons have been made between the land and atmospheric temperature and moisture to see the difference and its impacts on weather of twin cities i.e., Islamabad and Rawalpindi. The energy exchange parameters have been characterized by analyzing the impacts of weather parameters and turbulent fluxes on MHNP and surrounding cities. The potential rain water harvesting sites have been marked in the foothills. Weather and surface conditions become more favorable for the growth of vegetation by the end of April as the spring season reaches at its peak. There is the start of growing season in the month of April whereas the vegetation becomes thick over time during the month of May over Margalla hills however, the energy exchange parameters follow the same pattern in May as in April. The relative humidity remains between 18 - 55 % and the atmospheric temperature

  9. Global Manufacturing Research: Experience Exchange Group (EEG) contributions

    DEFF Research Database (Denmark)

    Bruun, Peter

    1998-01-01

    The intention of this paper is to clarify if and how an ExperienceExchange Group (EEG) can be involved in a research process in the areaof industrial management. For exemplification of the topic an ongoingresearch in global manufacturing is referred to. In this research itwas after a series...... of preliminary studies found interesting to set upan EEG composed of representatives from industry and a researcher. Inthe paper some general research methods pertinent to the areaindustrial management is discussed. The EEG concept is introduced andcharacterised in comparison with the other methods. EEG...... activities aredescribed and a tentative coupling to the phases in a research processis proposed. Following this is a discussion of methodological andquality requirements. It is considered how EEG activities couldpossible contribute to an industrial rooted research. The paper endsup looking at future research...

  10. Geometrical contributions to the exchange constants: Free electrons with spin-orbit interaction

    Science.gov (United States)

    Freimuth, Frank; Blügel, Stefan; Mokrousov, Yuriy

    2017-05-01

    Using thermal quantum field theory, we derive an expression for the exchange constant that resembles Fukuyama's formula for orbital magnetic susceptibility (OMS). Guided by this formal analogy between the exchange constant and OMS, we identify a contribution to the exchange constant that arises from the geometrical properties of the band structure in mixed phase space. We compute the exchange constants for free electrons and show that the geometrical contribution is generally important. Our formalism allows us to study the exchange constants in the presence of spin-orbit interaction. Thereby, we find sizable differences between the exchange constants of helical and cycloidal spin spirals. Furthermore, we discuss how to calculate the exchange constants based on a gauge-field approach in the case of the Rashba model with an additional exchange splitting, and we show that the exchange constants obtained from this gauge-field approach are in perfect agreement with those obtained from the quantum field theoretical method.

  11. Upland beech trees significantly contribute to forest methane exchange

    Science.gov (United States)

    Machacova, Katerina; Maier, Martin; Svobodova, Katerina; Halaburt, Ellen; Haddad, Sally; Lang, Friederike; Urban, Otmar

    2016-04-01

    . Compared to beech trees, forest floor was a sink for CH4 on the both sites. The deposition rates reached -52 and -161 μg CH4 m-2 soil area h-1 at the White Carpathians and Black Forest site, respectively. Concluded, CH4 emissions from upland beech trees significantly contribute to total CH4 flux and have to be counted towards the overall CH4 balance of beech forest. Acknowledgement This research was financially supported by the Czech Academy of Sciences and the German Academic Exchange Service within the project "Methane (CH4) and nitrous oxide (N2O) emissions from Fagus sylvatica trees" (DAAD-15-03), National Programme for Sustainability I (LO1415) and DFG project (MA 5826/2-1). We thank Marek Jakubik for technical support and Sinikka Paulus for help by field measurements.

  12. A new hybrid ion exchanger: Effect of system parameters on the adsorption of vanadium (V)

    Energy Technology Data Exchange (ETDEWEB)

    Yeom, Bong-Yeol [Nonwovens Cooperative Research Center, College of Textiles, North Carolina State University, Raleigh, NC 27695-8301 (United States); Lee, Chang-Soo [School of Applied Chemistry and Biological Engineering, College of Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Hwang, Taek-Sung, E-mail: tshwang@cnu.ac.kr [School of Applied Chemistry and Biological Engineering, College of Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2009-07-15

    The hybrid ion exchanger consisted of PONF-g-GMA anion fibrous exchanger and IRA-96 bead-type anion exchanger was developed by combining different types of layers with hot-melt adhesive. Its ion exchange capacity and the pressure drop with flow rate of water were measured and the adsorption of vanadium (V) ions on the hybrid ion exchanger was evaluated with various process parameters such as pH, initial concentration, and temperature. It was observed that the adsorption kinetics of vanadium (V) ions on the hybrid ion exchanger could be analyzed with pseudo-second-order model.

  13. Pion-exchange contribution to the parity-violating asymmetry in p-->p scattering

    Science.gov (United States)

    Silbar, Richard R.; Kloet, W. M.; Kisslinger, Leonard S.; Dubach, J.

    1989-11-01

    Charged pion exchange, resulting in an nΔ++ state, contributes positively to the weak scattering asymmetry in longitudinally polarized p-->p scattering at medium energy. This pion-exchange contribution combined with the traditional ρ and ω ``elastic'' contributions moves the total theoretical prediction into better agreement with the 800-MeV experimental data point. The pion-exchange contribution has both inelastic and elastic scattering components and is sizable even below the pion production threshold. Strong distortions enhance the magnitude of the effect.

  14. Pion-exchange contribution to the parity-violating asymmetry in rvec p p scattering

    Energy Technology Data Exchange (ETDEWEB)

    Silbar, R.R. (Theoretical Division, Los Alamos National Laboratory, University of California, Los Alamos, New Mexico 87545 (US)); Kloet, W.M. (Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903); Kisslinger, L.S. (Department of Physics, Carnegie-Mellon University, Pittsburgh, Pennsylvania 15213); Dubach, J. (Department of Physics and Astronomy, University of Massachusetts, Amherst, Massachusetts 01003 Continuous Electron Beam Accelerator Facility (CEBAF), 12000 Jefferson Avenue, Newport News, Virginia 23606)

    1989-11-01

    Charged pion exchange, resulting in an {ital n}{Delta}{sup ++} state, contributes positively to the weak scattering asymmetry in longitudinally polarized {ital {rvec p}p} scattering at medium energy. This pion-exchange contribution combined with the traditional {rho} and {omega} elastic'' contributions moves the total theoretical prediction into better agreement with the 800-MeV experimental data point. The pion-exchange contribution has both inelastic and elastic scattering components and is sizable even below the pion production threshold. Strong distortions enhance the magnitude of the effect.

  15. Influencing parameters on performance of a mantle heat exchanger ...

    African Journals Online (AJOL)

    Thermal performance of a solar water heater mainly depends on the thermal stratification. Thermal stratification in solar water tanks is essential for a better performance of energy storage systems where these tanks are integrated. In this research work, the performance of a solar water heater with a mantle heat exchanger is ...

  16. Pion-exchange contribution to the parity-violating asymmetry in pp scattering

    Science.gov (United States)

    Silbar, Richard R.; Kloet, W. M.; Kisslinger, Leonard S.; Dubach, J.

    1989-05-01

    Charged pion exchange, producing nΔ++ intermediate states, contributes negatively to the weak scattering asymmetry in longitudinally-polarized pp scattering. Including this contribution moves the theoretical prediction away from the 800 MeV experimental datum. The pion-exchange contribution has both inelastic and elastic scattering components and is sizeable even below the pion production threshold. Strong distortions enhance the magnitude of the effect.

  17. Pion-exchange contribution to the parity-violating asymmetry in pp scattering

    Energy Technology Data Exchange (ETDEWEB)

    Silbar, R.R. (Los Alamos National Laboratory, Los Alamos, NM 87545 (US)); Kloet, W.M. (Rutgers University, New Brunswick, NJ 08903); Kisslinger, L.S. (Carnegie-Mellon University, Pittsburgh, PA 15213); Dubach, J. (University of Massachusetts, Amherst, MA 01003)

    1989-05-01

    Charged pion exchange, producing n{Delta}{sup ++} intermediate states, contributes negatively to the weak scattering asymmetry in longitudinally-polarized pp scattering. Including this contribution moves the theoretical prediction away from the 800 MeV experimental datum. The pion-exchange contribution has both inelastic and elastic scattering components and is sizeable even below the pion production threshold. Strong distortions enhance the magnitude of the effect.

  18. Explaining contributions to public goods : Formalizing the social exchange heuristic

    NARCIS (Netherlands)

    Dijkstra, J.

    The public good game is a popular model of cooperation problems. Rational egoism predicts that in finitely repeated public good games no contributions are made. At least 4 observations are inconsistent with this prediction: contributions (i) are frequently positive, (ii) increase in the marginal

  19. Factors contributing to attitude exchange amongst preservice elementary teachers

    Science.gov (United States)

    Palmer, David H.

    2002-01-01

    Previous research has shown that elementary education majors often dislike science and lack confidence in their ability to teach it. This is an important problem because students who hold these attitudes are likely to avoid teaching science, or teach it poorly, when they become teachers. It is therefore necessary to identify preservice elementary teachers who hold negative attitudes towards science, and attempt to convert these attitudes to positive before they become teachers. This study was designed to identify students whose attitudes had changed from negative to positive (i.e., attitude exchange had occurred) after participating in a one-semester elementary science education course, and to identify the course factors that were responsible. Four participants were individually interviewed. The transcripts indicated that attitude exchange had occurred for each of the four students. Each student described several features of the course that had a positive influence. These were of three main types: personal attributes of the tutor, specific teaching strategies, and external validation. It was proposed that many of the individual factors were effective because they represented either performance accomplishments or vicarious experience as defined by Bandura (Psychological Review, 84, 1977, 191-215).

  20. Analysis of the Technological Parameters of the Heat Exchanger in the Heating Pipe

    Directory of Open Access Journals (Sweden)

    Knyazev Vladimir

    2017-01-01

    Full Text Available The main purpose of this article is to analyze the selecting of technological parameters for the heat exchanger to improve the heat transfer and reduce the noise during operation in the heating pipe, which is used in the different systems of the planes and helicopters. In result of this study, the best technical parameters are found, considering different variations of deformation cutting heat exchanger pipes.

  1. The two-photon exchange contribution to elastic electron-nucleon scattering at large momentum transfer

    Energy Technology Data Exchange (ETDEWEB)

    Andrei V. Afanasev; Stanley J. Brodsky; Carl E. Carlson; Yu-Chun Chen; Marc Vanderhaeghen

    2005-01-01

    We estimate the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer by using a quark-parton representation of virtual Compton scattering. We thus can relate the two-photon exchange amplitude to the generalized parton distributions which also enter in other wide angle scattering processes. We find that the interference of one- and two-photon exchange contribution is able to substantially resolve the difference between electric form factor measurements from Rosenbluth and polarization transfer experiments.

  2. The dominant surface-topography contributions of individual subduction parameters

    Science.gov (United States)

    Crameri, Fabio; Lithgow-Bertelloni, Carolina; Tackley, Paul

    2017-04-01

    It is no secret, not any longer, that dynamic processes below the plate exert a significant contribution to the elevation of the plate at the surface (e.g., Flament et al., 2013). We have therefore studied* the individual impact each and every major subduction parameter has on surface topography. This allows us to qualitatively compare the different sources amongst each other, and to quantify their actual potential to vertically deflect the surface. The gained knowledge from this compilation is crucial: We might finally be able to link the directly-observable surface topography to the dynamics (buoyancy, rheology, and geometry) of the subduction system. *This study is made possible by the efficient convection code StagYY (Tackley 2008), the largely-automated post-processing and visualisation toolbox StagLab (www.fabiocrameri.ch/software), and crucial model developments (Crameri and Tackley, 2015; Crameri et al., G-cubed, submitted, Crameri and Lithgow-Bertelloni, Tectonophysics, submitted). REFERENCES 
Flament, N., M. Gurnis, and R. D. Müller (2013), A review of observations and models of dynamic topography, Lithosphere, 5(2), 189-210. Crameri, F., and P. J. Tackley (2015), Parameters controlling dynamically self-consistent plate tectonics and single-sided subduction in global models of mantle convection, J. Geophys. Res. Solid Earth, 120(5), 3680-3706. Crameri, F., C. R. Lithgow-Bertelloni, and P. J. Tackley (submitted), The dynamical control of subduction parameters on surface topography, Geochem. Geophys. Geosyst. Crameri, F., and C. R. Lithgow-Bertelloni (submitted), Dynamic Mantle-Transition-Zone Controls on Upper-Plate Tilt, Tectonophysics. Tackley, P.J (2008) Modelling compressible mantle convection with large viscosity contrasts in a three- dimensional spherical shell using the yin-yang grid. Physics of the Earth and Planetary Interiors 171(1-4), 7-18.

  3. Improved group contribution parameter set for the application of solubility parameters to melt extrusion.

    Science.gov (United States)

    Just, Susann; Sievert, Frank; Thommes, Markus; Breitkreutz, Jörg

    2013-11-01

    Hot-melt extrusion is gaining importance for the production of amorphous solid solutions; in parallel, predictive tools for estimating drug solubility in polymers are increasingly demanded. The Hansen solubility parameter (SP) approach is well acknowledged for its predictive power of the miscibility of liquids as well as the solubility of some amorphous solids in liquid solvents. By solely using the molecular structure, group contribution (GC) methods allow the calculation of Hansen SPs. The GC parameter sets available were derived from liquids and polymers which conflicts with the object of prediction, the solubility of solid drugs. The present study takes a step from the liquid based SPs toward their application to solid solutes. On the basis of published experimental Hansen SPs of solid drugs and excipients only, a new GC parameter set was developed. In comparison with established parameter sets by van Krevelen/Hoftyzer, Beerbower/Hansen, Breitkreutz and Stefanis/Panayiotou, the new GC parameter set provides the highest overall predictive power for solubility experiments (correlation coefficient r = -0.87 to -0.91) as well as for literature data on melt extrudates and casted films (r = -0.78 to -0.96). Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Optimization principle of operating parameters of heat exchanger by using CFD simulation

    Directory of Open Access Journals (Sweden)

    Mičieta Jozef

    2016-01-01

    Full Text Available Design of effective heat transfer devices and minimizing costs are desired sections in industry and they are important for both engineers and users due to the wide-scale use of heat exchangers. Traditional approach to design is based on iterative process in which is gradually changed design parameters, until a satisfactory solution is achieved. The design process of the heat exchanger is very dependent on the experience of the engineer, thereby the use of computational software is a major advantage in view of time. Determination of operating parameters of the heat exchanger and the subsequent estimation of operating costs have a major impact on the expected profitability of the device. There are on the one hand the material and production costs, which are immediately reflected in the cost of device. But on the other hand, there are somewhat hidden costs in view of economic operation of the heat exchanger. The economic balance of operation significantly affects the technical solution and accompanies the design of the heat exchanger since its inception. Therefore, there is important not underestimate the choice of operating parameters. The article describes an optimization procedure for choice of cost-effective operational parameters for a simple double pipe heat exchanger by using CFD software and the subsequent proposal to modify its design for more economical operation.

  5. Progress in counterfeit deterrence: the contribution of information exchange

    Science.gov (United States)

    Lancaster, Ian M.; Kontnik, Lewis T.

    1996-03-01

    In this paper we establish the need for communication between organizations involved in the fight against counterfeiting crime. We also examine the paradox in providing information that could serve the criminal as well as those attempting to protect themselves from criminal activity. Counterfeiting is estimated to account for over 5% of world trade. It is a global operation with no respect for international borders. It is increasingly sophisticated and increasingly the province of organized crime, which applies the techniques developed for drug distribution to the production and distribution of counterfeit articles. To fight this crime there is an increasing plethora of authenticating features and technologies available. Many companies do not recognize the problem and the number of anticounterfeit technologies can be confusing for potential users. There is therefore a need for information about them, their comparative characteristics, to be easily available. At present there is inadequate communication between those who develop and produce anti-counterfeiting devices and those who use them, notwithstanding the marketing efforts of the former. Communication which stimulates and encourages the spread of information between those engaged in the fight against counterfeit crime can only help in that fight. But what we term 'the communication paradox' requires circumspection and care in the content and the distribution of such information. The communication paradox is that the better the channels of communication, the easier it is for criminals to get hold of that information. The challenge is to institute communications which are effective but restrictive. More communication of information between those engaged in counterfeit deterrence will enhance individual companies' and organizations' anticounterfeit efforts and thus contribute to an overall improvement in the fight against counterfeit crime.

  6. A contribution to theory and practice of nonlinear parameter optimization

    NARCIS (Netherlands)

    Stol, P.T.

    1975-01-01

    Nonlinear parameter optimization in least squares was studied from a point of view of differential geometry. Properties of curvilinear coordinates, scale factors and curvature were investigated. Parameters of the condition function were expressed as functions of algorithm parameters to

  7. Contribution of terms containing Z-boson exchange to the luminosity measurements at LEP

    Science.gov (United States)

    Beenakker, W.; Pietrzyk, B.

    1992-12-01

    We have investigated the contribution of terms containing Z-boson exchange to the luminosity measurements at LEP. Comparing the Monte Carlo program BABAMC and the semi-analytical program ALIBABA, we have determined the technical precision of the corresponding O( α) calculation in BABAMC to be 0.03%. Using the ALIBABA program we have assessed the higher-order corrections to these Z-boson exchange contributions to be of the order of 0.1% for the present luminosity measurements. The total theoretical error on the luminosity calculation for LEP experiments is at present not larger than 0.3%.

  8. Exchange-current contribution to the pion-deuteron scattering length

    Science.gov (United States)

    Robilotta, M. R.

    1980-05-01

    Chiral symmetry, implemented by means of effective lagrangians, is used to evaluate the exchange-current contribution to the pion-deuteron scattering length. It is shown that this approximate ssymmetry is responsible for partial cancellations, yielding an overall contribution of about 10% of the total scattering length. Work supported in part by the Conselho Nacional de Desenvolvimento Cientifico e Tecnológico, Brazil.

  9. Genetic parameters of reproductive traits in pigs: a contribution

    Directory of Open Access Journals (Sweden)

    G. Pagnacco

    2011-03-01

    Full Text Available Generally pig breeding efficiency is defined as the number of piglets weaned per sow per year, so in every pig breeding programmes, great emphasis is placed on improving reproductive traits in sow lines and generally, the evaluation of litter size is carried out in most selection planes. Usually, the reproduction breeding goal is to increase the number of piglets born, but this trait, as reported by Hanenberg et al. (2001 gives an undesirable correlation with the number of stillborn piglets. Litter size is the result of a large number of traits as number of total piglets born, number of born alive, stillbirth, weaned survival; as reported by Tummaruk et al. (2000 the variation in these parameters is influenced by genetic value of the sow and by environmental factors, such as management and season. Regarding the genetic influence on the litter size, we know that the breed can influence the number of born, but its interaction with stillbirth is not significant, although Leenhouwers et al. (1999 found an higher stillbirth incidence in purebred than in crossbred litters........

  10. Non-coherent contributions in charge-exchange reactions and η-η{sup '} mixing

    Energy Technology Data Exchange (ETDEWEB)

    Nekrasov, M.L. [NRC ' ' Kurchatov Institute' ' , Institute for High Energy Physics, Protvino (Russian Federation)

    2017-05-15

    We analyse K{sup -}p → (η,η{sup '},π{sup 0})Λ on the basis of the fit of data in a wide region of energies, and π{sup -}p → (η,η{sup '})n at the energies of GAMS-4π. We show that disagreements between the data and the predictions of Regge theory may be explained by the mode change of summation of intermediate contributions at increasing energy, from coherent to non-coherent. A method of experimental measurement of the non-coherent contributions is proposed. On the basis of available data on the charge-exchange reactions the η-η{sup '} mixing is estimated. (orig.)

  11. Intercomparison and assessment of turbulent and physiological exchange parameters of grassland

    Directory of Open Access Journals (Sweden)

    E. Nemitz

    2009-08-01

    Full Text Available Commonly, the micrometeorological parameters that underline the calculations of surface atmosphere exchange fluxes (e.g. friction velocity and sensible heat flux and parameters used to model exchange fluxes with SVAT-type parameterisations (e.g. latent heat flux and canopy temperature are measured with a single set of instrumentation and are analysed with a single methodology. This paper evaluates uncertainties in these measurements with a single instrument, by comparing the independent results from nine different institutes during the international GRAMINAE integrated field experiment over agricultural grassland near Braunschweig, Lower Saxony, Germany. The paper discusses uncertainties in measuring friction velocity, sensible and latent heat fluxes, canopy temperature and investigates the energy balance closure at this site. Although individual 15-min flux calculations show a large variability between the instruments, when averaged over the campaign, fluxes agree within 2% for momentum and 11% for sensible heat. However, the spread in estimates of latent heat flux (λE is larger, with standard deviations of averages of 18%. The dataset averaged over the different instruments fails to close the energy budget by 20%, significantly larger than the uncertainties in the individual flux corrections. However, if the largest individual turbulent flux estimates are considered, energy closure can be achieved, indicating that the closure gap is within the spread of the measurements. The uncertainty in λE feeds results in an uncertainty in the bulk stomatal resistance, which further adds to the uncertainties in the estimation of the canopy temperature that controls the exchange. The paper demonstrated how a consensus dataset was derived, which is used by the individual investigators to calculate fluxes and drive their models.

  12. Improved semiconductor lattice parameters and band gaps from a middle-range screened hybrid exchange functional.

    Science.gov (United States)

    Lucero, M J; Henderson, T M; Scuseria, G E

    2012-04-11

    We show that the middle-range exchange-correlation hybrid of Henderson, Izmaylov, Scuseria and Savin (HISS) performs extremely well for elemental and binary semiconductors with narrow or visible spectrum band gaps, as well as some wider gap or more ionic systems used in devices. The lattice parameters are superior to those predicted by the screened hybrid functional of Heyd, Scuseria and Ernzerhof (HSE), and provide a significant improvement over the geometries predicted by typical semilocal functionals, yielding results competitive with PBEsol, which was specially tuned for solids. HISS also yields band gaps superior to those produced by functionals developed specifically for the solid state. Timings indicate that HISS is more computationally efficient than HSE, implying that the high quality lattice constants coupled with improved optical band gap predictions render HISS a useful adjunct to HSE in the modeling of geometry-sensitive semiconductors.

  13. Solar Wind Charge Exchange Contribution To The ROSAT Sky Survey Maps

    Science.gov (United States)

    Uprety, Y.; Chiao, M.; Collier, M. R.; Cravens, T.; Galeazzi, M.; Koutroumpa, D.; Kuntz, K. D.; Lallement, R.; Lepri, S. T.; Liu, W.; hide

    2016-01-01

    DXL (Diffuse X-ray emission from the Local Galaxy) is a sounding rocket mission designed to estimate the contribution of solar wind charge eXchange (SWCX) to the diffuse X-ray background and to help determine the properties of the Local Hot Bubble. The detectors are large area thin-window proportional counters with a spectral response that is similar to that of the PSPC (Position Sensitive Proportional Counters) used in the ROSAT All Sky Survey (RASS). A direct comparison of DXL and RASS data for the same part of the sky viewed from quite different vantage points in the solar system, and the assumption of approximate isotropy for the solar wind, allowed us to quantify the SWCX contribution to all six RASS bands (R1-R7, excluding R3). We find that the SWCX contribution at l = 140 degrees, b = 0 degrees, where the DXL path crosses the Galactic plane, is 33 percent plus or minus 6 percent (statistical) plus or minus 12 percent (systematic) for R1, 44 percent plus or minus 6 percent plus or minus 5 percent for R2, 18 percent plus or minus 12 percent plus or minus 11 percent for R4, 14 percent plus or minus 11 percent plus or minus 9 percent for R5, and negligible for the R6 and R7 bands. Reliable models for the distribution of neutral H and He in the solar system permit estimation of the contribution of interplanetary SWCX emission over the the whole sky and correction of the RASS maps. We find that the average SWCX contribution in the whole sky is 26 percent plus or minus 6 percent plus or minus 13 percent for R1, 30 percent plus or minus 4 percent plus or minus 4 percent for R2, 8 percent plus or minus 5 percent plus or minus 5 percent for R4, 6 percent plus or minus 4 percent plus or minus 4 percent for R5, and negligible for R6 and R7.

  14. Contribution of understorey vegetation and soil processes to boreal forest isoprenoid exchange

    Science.gov (United States)

    Mäki, Mari; Heinonsalo, Jussi; Hellén, Heidi; Bäck, Jaana

    2017-03-01

    Boreal forest floor emits biogenic volatile organic compounds (BVOCs) from the understorey vegetation and the heterogeneous soil matrix, where the interactions of soil organisms and soil chemistry are complex. Earlier studies have focused on determining the net exchange of VOCs from the forest floor. This study goes one step further, with the aim of separately determining whether the photosynthesized carbon allocation to soil affects the isoprenoid production by different soil organisms, i.e., decomposers, mycorrhizal fungi, and roots. In each treatment, photosynthesized carbon allocation through roots for decomposers and mycorrhizal fungi was controlled by either preventing root ingrowth (50 µm mesh size) or the ingrowth of roots and fungi (1 µm mesh) into the soil volume, which is called the trenching approach. Isoprenoid fluxes were measured using dynamic (steady-state flow-through) chambers from the different treatments. This study aimed to analyze how important the understorey vegetation is as a VOC sink. Finally, a statistical model was constructed based on prevailing temperature, seasonality, trenching treatments, understory vegetation cover, above canopy photosynthetically active radiation (PAR), soil water content, and soil temperature to estimate isoprenoid fluxes. The final model included parameters with a statistically significant effect on the isoprenoid fluxes. The results show that the boreal forest floor emits monoterpenes, sesquiterpenes, and isoprene. Monoterpenes were the most common group of emitted isoprenoids, and the average flux from the non-trenched forest floor was 23 µg m-2 h-1. The results also show that different biological factors, including litterfall, carbon availability, biological activity in the soil, and physico-chemical processes, such as volatilization and absorption to the surfaces, are important at various times of the year. This study also discovered that understorey vegetation is a strong sink of monoterpenes. The

  15. Outlier treatment for improving parameter estimation of group contribution based models for upper flammability limit

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Abildskov, Jens; Sin, Gürkan

    2015-01-01

    Flammability data is needed to assess the risk of fire and explosions. This study presents a new group contribution (GC) model to predict the upper flammability limit UFL oforganic chemicals. Furthermore, it provides a systematic method for outlier treatment inorder to improve the parameter...

  16. Dependence of spectral characteristics on parameters describing CO2 exchange between crop species and the atmosphere

    Science.gov (United States)

    Uździcka, Bogna; Stróżecki, Marcin; Urbaniak, Marek; Juszczak, Radosław

    2017-07-01

    The aim of this paper is to demonstrate that spectral vegetation indices are good indicators of parameters describing the intensity of CO2 exchange between crops and the atmosphere. Measurements were conducted over 2011-2013 on plots of an experimental arable station on winter wheat, winter rye, spring barley, and potatoes. CO2 fluxes were measured using the dynamic closed chamber system, while spectral vegetation indices were determined using SKYE multispectral sensors. Based on spectral data collected in 2011 and 2013, various models to estimate net ecosystem productivity and gross ecosystem productivity were developed. These models were then verified based on data collected in 2012. The R2 for the best model based on spectral data ranged from 0.71 to 0.83 and from 0.78 to 0.92, for net ecosystem productivity and gross ecosystem productivity, respectively. Such high R2 values indicate the utility of spectral vegetation indices in estimating CO2 fluxes of crops. The effects of the soil background turned out to be an important factor decreasing the accuracy of the tested models.

  17. Estimate the contribution of incubation parameters influence egg hatchability using multiple linear regression analysis.

    Science.gov (United States)

    Khalil, Mohamed H; Shebl, Mostafa K; Kosba, Mohamed A; El-Sabrout, Karim; Zaki, Nesma

    2016-08-01

    This research was conducted to determine the most affecting parameters on hatchability of indigenous and improved local chickens' eggs. Five parameters were studied (fertility, early and late embryonic mortalities, shape index, egg weight, and egg weight loss) on four strains, namely Fayoumi, Alexandria, Matrouh, and Montazah. Multiple linear regression was performed on the studied parameters to determine the most influencing one on hatchability. The results showed significant differences in commercial and scientific hatchability among strains. Alexandria strain has the highest significant commercial hatchability (80.70%). Regarding the studied strains, highly significant differences in hatching chick weight among strains were observed. Using multiple linear regression analysis, fertility made the greatest percent contribution (71.31%) to hatchability, and the lowest percent contributions were made by shape index and egg weight loss. A prediction of hatchability using multiple regression analysis could be a good tool to improve hatchability percentage in chickens.

  18. Identification of the contribution of contact and aerial biomechanical parameters in acrobatic performance.

    Science.gov (United States)

    Haering, Diane; Huchez, Aurore; Barbier, Franck; Holvoët, Patrice; Begon, Mickaël

    2017-01-01

    Teaching acrobatic skills with a minimal amount of repetition is a major challenge for coaches. Biomechanical, statistical or computer simulation tools can help them identify the most determinant factors of performance. Release parameters, change in moment of inertia and segmental momentum transfers were identified in the prediction of acrobatics success. The purpose of the present study was to evaluate the relative contribution of these parameters in performance throughout expertise or optimisation based improvements. The counter movement forward in flight (CMFIF) was chosen for its intrinsic dichotomy between the accessibility of its attempt and complexity of its mastery. Three repetitions of the CMFIF performed by eight novice and eight advanced female gymnasts were recorded using a motion capture system. Optimal aerial techniques that maximise rotation potential at regrasp were also computed. A 14-segment-multibody-model defined through the Rigid Body Dynamics Library was used to compute recorded and optimal kinematics, and biomechanical parameters. A stepwise multiple linear regression was used to determine the relative contribution of these parameters in novice recorded, novice optimised, advanced recorded and advanced optimised trials. Finally, fixed effects of expertise and optimisation were tested through a mixed-effects analysis. Variation in release state only contributed to performances in novice recorded trials. Moment of inertia contribution to performance increased from novice recorded, to novice optimised, advanced recorded, and advanced optimised trials. Contribution to performance of momentum transfer to the trunk during the flight prevailed in all recorded trials. Although optimisation decreased transfer contribution, momentum transfer to the arms appeared. Findings suggest that novices should be coached on both contact and aerial technique. Inversely, mainly improved aerial technique helped advanced gymnasts increase their performance. For both

  19. Identification of the contribution of contact and aerial biomechanical parameters in acrobatic performance.

    Directory of Open Access Journals (Sweden)

    Diane Haering

    Full Text Available Teaching acrobatic skills with a minimal amount of repetition is a major challenge for coaches. Biomechanical, statistical or computer simulation tools can help them identify the most determinant factors of performance. Release parameters, change in moment of inertia and segmental momentum transfers were identified in the prediction of acrobatics success. The purpose of the present study was to evaluate the relative contribution of these parameters in performance throughout expertise or optimisation based improvements. The counter movement forward in flight (CMFIF was chosen for its intrinsic dichotomy between the accessibility of its attempt and complexity of its mastery.Three repetitions of the CMFIF performed by eight novice and eight advanced female gymnasts were recorded using a motion capture system. Optimal aerial techniques that maximise rotation potential at regrasp were also computed. A 14-segment-multibody-model defined through the Rigid Body Dynamics Library was used to compute recorded and optimal kinematics, and biomechanical parameters. A stepwise multiple linear regression was used to determine the relative contribution of these parameters in novice recorded, novice optimised, advanced recorded and advanced optimised trials. Finally, fixed effects of expertise and optimisation were tested through a mixed-effects analysis.Variation in release state only contributed to performances in novice recorded trials. Moment of inertia contribution to performance increased from novice recorded, to novice optimised, advanced recorded, and advanced optimised trials. Contribution to performance of momentum transfer to the trunk during the flight prevailed in all recorded trials. Although optimisation decreased transfer contribution, momentum transfer to the arms appeared.Findings suggest that novices should be coached on both contact and aerial technique. Inversely, mainly improved aerial technique helped advanced gymnasts increase their

  20. Virtual Protein Purification: A Simple Exercise to Introduce pH as A Parameter That Effects Ion Exchange Chromatography

    Science.gov (United States)

    Clark, Daniel D.; Edwards, Daniel J.

    2018-01-01

    This article describes a simple exercise using a free, easy-to-use, established online program. The exercise helps to reinforce protein purification concepts and introduces undergraduates to pH as a parameter that affects anion-exchange chromatography. The exercise was tested with biochemistry majors at California State University-Chico. Given the…

  1. Heterodimerization of Arabidopsis calcium/proton exchangers contributes to regulation of guard cell dynamics and plant defense responses

    Science.gov (United States)

    "Arabidopsis thaliana" cation exchangers (CAX1 and CAX3) are closely related tonoplast-localized calcium/proton (Ca(2+)/H+) antiporters that contribute to cellular Ca(2+) homeostasis. CAX1 and CAX3 were previously shown to interact in yeast; however, the function of this complex in plants has remain...

  2. The contribution of mosses to the carbon and water exchange of artic ecosystems: quantification and relationships with system properties

    NARCIS (Netherlands)

    Douma, J.C.; Wijk, van M.T.; Lang, S.I.; Shaver, G.R.

    2007-01-01

    Water vapour and CO2 exchange were measured in moss-dominated vegetation using a gas analyser and a 0.3 × 0.3 m chamber at 17 sites near Abisko, Northern Sweden and 21 sites near Longyearbyen, Svalbard, to quantify the contribution of mosses to ecosystem level fluxes. With the help of a simple

  3. The effect of the application of the biological control agent EM1 on gas exchange parameters and productivity of Pisum sativum L. infected with Fusarium oxysporum Schlecht.

    Directory of Open Access Journals (Sweden)

    Adam Okorski

    2012-12-01

    Full Text Available A pot experiment on different methods of EM 1 application was conducted in the period 2002-2004. The study was carried out under controlled growth conditions. The experimental factor was the method of EM1 application. Before application, the biological preparation EM1 was propagated as recommended by the manufacturer (Greenland. The health status of the aboveground parts of 'Ramrod' pea plants was estimated at the flowering stage. The assessment of pea leaf gas exchange parameters (An, E, Gs, and Ci was made using a LI-Cor 6400 Portable Photosynthesis System. Soil application of EM1 combined with chemical control contributed to inhibiting Fusarium wilt of pea. Foliar application of EM1 combined with chemical control increased all gas exchange rates of pea leaves. Fusarium wilt of pea insignificantly decreased all gas exchange rates of pea leaves and the number of seeds per pod. The best method of EM1 application was soil treatment combined with chemical control, which increased all yield-related morphometric parameters of pea.

  4. The contribution of the ECU to exchange rate stability. A reply

    Directory of Open Access Journals (Sweden)

    H. JAGER

    2013-12-01

    Full Text Available A brief reply to Sarcinelli’s criticism of the authors’ article The private ECU’s potential impact on Global and European exchange-rate stability (1988. The authors rebut the criticisms and seek to clarify their reasoning. They maintain their core hypothesis that the growth of the ECU does not necessarily enhance the stability of exchange rates but may lead to instability too.

  5. Private transfers with incomplete information: A contribution to the "altruism-exchange motivation for transfers" debate

    OpenAIRE

    Eli Feinerman; Edward J. Seiler

    2002-01-01

    We examine the role of altruism in determining optimal transfers from a principal (a mother) to selfish agents (her children) in return for attention services. Transfer-attention contracts are studied in a setting in which informational asymmetries arise from the inability of a parent to determine the extent of her children's selfishness. We find a predominating exchange motive for transfers in the symmetric informational regime we study. However, both altruism and exchange are important moti...

  6. Combined Yamamoto approach for simultaneous estimation of adsorption isotherm and kinetic parameters in ion-exchange chromatography.

    Science.gov (United States)

    Rüdt, Matthias; Gillet, Florian; Heege, Stefanie; Hitzler, Julian; Kalbfuss, Bernd; Guélat, Bertrand

    2015-09-25

    Application of model-based design is appealing to support the development of protein chromatography in the biopharmaceutical industry. However, the required efforts for parameter estimation are frequently perceived as time-consuming and expensive. In order to speed-up this work, a new parameter estimation approach for modelling ion-exchange chromatography in linear conditions was developed. It aims at reducing the time and protein demand for the model calibration. The method combines the estimation of kinetic and thermodynamic parameters based on the simultaneous variation of the gradient slope and the residence time in a set of five linear gradient elutions. The parameters are estimated from a Yamamoto plot and a gradient-adjusted Van Deemter plot. The combined approach increases the information extracted per experiment compared to the individual methods. As a proof of concept, the combined approach was successfully applied for a monoclonal antibody on a cation-exchanger and for a Fc-fusion protein on an anion-exchange resin. The individual parameter estimations for the mAb confirmed that the new approach maintained the accuracy of the usual Yamamoto and Van Deemter plots. In the second case, offline size-exclusion chromatography was performed in order to estimate the thermodynamic parameters of an impurity (high molecular weight species) simultaneously with the main product. Finally, the parameters obtained from the combined approach were used in a lumped kinetic model to simulate the chromatography runs. The simulated chromatograms obtained for a wide range of gradient lengths and residence times showed only small deviations compared to the experimental data. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Intestinal anion exchange in marine teleosts is involved in osmoregulation and contributes to the oceanic inorganic carbon cycle.

    Science.gov (United States)

    Grosell, M

    2011-07-01

    Marine teleost fish osmoregulation involves seawater ingestion and intestinal fluid absorption. Solute coupled fluid absorption by the marine teleost fish intestine has long been believed to be the product of Na(+) and Cl(-) absorption via the Na(+) :K(+) :2Cl(-) co-transporter (NKCC2). However, the past decade has revealed that intestinal anion exchange contributes significantly to Cl(-) absorption, in exchange for HCO(3) (-) secretion, and that this process is important for intestinal water absorption. In addition to contributing to solute coupled water absorption intestinal anion exchange results in luminal precipitation of CaCO(3) which acts to reduce luminal osmotic pressure and thus assist water absorption. Most recently, activity of apical H(+) -pumps, especially in distal segments of the intestine have been suggested to not only promote anion exchange, but also to reduce luminal osmotic pressure by preventing excess HCO(3)(-) concentrations from accumulating in intestinal fluids, thereby aiding water absorption. The present review summarizes and synthesizes the most recent advances in our view of marine teleosts osmoregulation, including our emerging understanding of epithelial transport of acid-base equivalents in the intestine, the consequences for whole organism acid-base balance and finally the impact of piscine CaCO(3) formation on the global oceanic carbon cycle. © 2011 The Author. Acta Physiologica © 2011 Scandinavian Physiological Society.

  8. Gas exchange parameters in leaves and ears of winter wheat Tricitum aestivum L. and its productivity under fungicide control conditions

    Directory of Open Access Journals (Sweden)

    Joanna K. Jarmołkowicz

    2012-12-01

    Full Text Available A research experiment was conducted in which rates of photosynthesis and transpiration were measured in leaves and ears of two winter wheat varieties grown under fungicide control conditions and without fungicide control. A LI-COR 6400 portable gas exchange system was used in the investigations. In most cases the fungicide Juwel was shown to have no effect on the gas exchange processes, whereas the other of the fungicidal agents applied - Swing - significantly decreased the gas exchange rates measured. Measurements of gas exchange parameters in ears showed that the intensity of gas exchange was low, in particular at the later stage of ear development. But the applied fungicide caused higher release of CO2 into the atmosphere than its uptake. Furthermore, the applied fungicides were found to significantly increase grain yield compared to the control treatment, both in the first and second year of the study. Among the tested varieties, 'Nutka' was characterized by higher productivity, in spite of lower 1000 kernel weight. However, this cultivar developed longer ears with a larger amount of grains.

  9. Severe Neonatal Hyperbilirubinemia; Causes and Contributing Factors Leading to Exchange Transfusion at Ghaem Hospital in Mashhad

    Directory of Open Access Journals (Sweden)

    Farhad Heydarian

    2010-12-01

    Full Text Available Hyperbilirubinemia is common in neonates; it can have a serious rising course. Due to its critical morbidity called "kernicterus", severe neonatal hyperbilirubinemia causes which lead to exchange transfusion, should be clarified. This descriptive cross sectional study performed with reviewing of files of 118 neonates weighting 2kg and more who had exchange transfusion in pediatrics ward at Ghaem training hospital in Mashhad from April 2004 to March 2007. Among 118 patients, 75 (63.6% were male, and 43 patients (36.4% were female. The most common cause of exchange transfusion was ABO incompatibility (38.1%. In order of frequency, unknown etiology (25.4%, Rh incompatibility (16.1% with no immune hydrops, Sepsis(8.5%, urinary tract infection (5.1% and others (3.4% (Including Crigler-Najjar and cephalohematoma were next ones. Vaginal delivery and exclusive breast feeding were detected as associated factors. Mean serum bilirubin levels was 28.7 mg/dl (SD. 9.2 ABO incompatibility. ABO incompatibility was the main cause of exchange transfusion. Male gender, vaginal delivery and exclusive breast feeding were seen more among patients who need to be exchanged. So in case of ABO incompatibility especially when delivery route is vaginal, newborns should be visited soon again after early discharge from hospital.

  10. Severe Neonatal Hyperbilirubinemia; Causes and Contributing Factors Leading to Exchange Transfusion at Ghaem Hospital in Mashhad

    Directory of Open Access Journals (Sweden)

    Farhad Heydarian

    2010-11-01

    Full Text Available "nHyperbilirubinemia is common in neonates; it can have a serious rising course. Due to its critical morbidity called "kernicterus", severe neonatal hyperbilirubinemia causes which lead to exchange transfusion, should be clarified. This descriptive cross sectional study performed with reviewing of files of 118 neonates weighting 2kg and more who had exchange transfusion in pediatrics ward at Ghaem training hospital in Mashhad from April 2004 to March 2007. Among 118 patients, 75 (63.6% were male, and 43 patients (36.4% were female. The most common cause of exchange transfusion was ABO incompatibility (38.1%. In order of frequency, unknown etiology (25.4%, Rh incompatibility (16.1% with no immune hydrops, Sepsis(8.5%, urinary tract infection (5.1% and others (3.4% (Including Crigler-Najjar and cephalohematoma were next ones. Vaginal delivery and exclusive breast feeding were detected as associated factors. Mean serum bilirubin levels was 28.7 mg/dl (SD. 9.2 ABO incompatibility. ABO incompatibility was the main cause of exchange transfusion. Male gender, vaginal delivery and exclusive breast feeding were seen more among patients who need to be exchanged. So in case of ABO incompatibility especially when delivery route is vaginal, newborns should be visited soon again after early discharge from hospital.

  11. The Effect of Water Stress on the Gas Exchange Parameters, Productivity and Seed Health of Buckwheat (Fagopyrum esculentum Moench

    Directory of Open Access Journals (Sweden)

    Agnieszka Pszczółkowska

    2012-12-01

    Full Text Available The present pot experiment studied the effect of different soil moisture contents (60 - 70% CWC (capillary water capacity - control; 30 - 35% CWC - water stress on buckwheat productivity, the gas exchange parameters and health of buckwheat nuts. It was found that water deficit affected adversely certain biometric features investigated (plant height, number of nuts per cluster and caused a decrease in seed weight per plant. It was also shown that water stress reduced the values of the investigated gas exchange parameters (photosynthesis rate, transpiration rate, intercellular-space CO2 concentration, and stomatal conductance relative to the control treatment. Different soil moisture contents did not have a clear effect on fungal colonization of seeds. The multiplex PCR assays did not enable the detection of the genes responsible for mycotoxin synthesis. Under water deficit conditions, an increase was found in the content of albumin and globulin fractions as well as of glutelin fractions.

  12. The contribution of the ECU to exchange-rate stability. A comment

    Directory of Open Access Journals (Sweden)

    M. SARCINELLI

    2013-12-01

    Full Text Available The article is a brief note criticising some essential elements of Jager and De Jong’s The private ECU’s potential impact on Global and European exchange-rate stability (1988. The author provides three points of criticism which undermine that article’s analysis. Firstly, the ECU ought to be considered in all its functions of an international reserve currency and not only as an investment currency. Secondly, the restrictiveness of the assumptions underlying the portfolio approach make the authors’ outcome useless in practice. Thirdly, the outcome of their calculations favours the hypothesis that the ECU creates exchange-rate stability.

  13. Hyperfine contributions to spin-exchange frequency shifts in the hydrogen maser

    NARCIS (Netherlands)

    Verhaar, B.J.; Koelman, J.M.V.A.; Stoof, H.T.C.; Luiten, O.J.; Crampton, S.B.

    1987-01-01

    We have rigorously included hyperfine interactions during electron-spin-exchange collisions between ground state hydrogen atoms. We predict additional frequency shifts which are not compensated for by the usual methods of tuning maser cavities. These shifts are large compared to the potential

  14. Bromodeoxyuridine does not contribute to sister chromatid exchange events in normal or Bloom syndrome cells

    NARCIS (Netherlands)

    van Wietmarschen, Niek; Lansdorp, Peter M.

    2016-01-01

    Sister chromatid exchanges (SCEs) are considered sensitive indicators of genome instability. Detection of SCEs typically requires cells to incorporate bromodeoxyuridine (BrdU) during two rounds of DNA synthesis. Previous studies have suggested that SCEs are induced by DNA replication over

  15. Effect of myelin water exchange on DTI-derived parameters in diffusion MRI: Elucidation of TE dependence.

    Science.gov (United States)

    Lin, Mu; He, Hongjian; Tong, Qiqi; Ding, Qiuping; Yan, Xu; Feiweier, Thorsten; Zhong, Jianhui

    2018-03-01

    Water exchange exists between different neuronal compartments of brain tissue but is often ignored in most diffusion models. The goal of the current study was to demonstrate the dependence of diffusion measurements on echo time (TE) in the human brain and to investigate the underlying effects of myelin water exchange. Five healthy subjects were examined with single-shot pulsed-gradient spin-echo echo-planar imaging with fixed duration (δ) and separation (Δ) of diffusion gradient pulses and a set of varying TEs. The effects of water exchange and intrinsic T2 difference in cellular environments were investigated with Monte Carlo simulations. Both in vivo measurements and simulations showed that fractional anisotropy (FA) and axial diffusivity (AD) had positive correlations with TE, while radial diffusivity (RD) showed a negative correlation, which is consistent with a previous study. The simulation results further indicated the sensitivity of TE dependence to the change of g-ratio. The exchange between myelin and intra/extra-axonal water pools often plays a non-negligible role in the observed TE dependence of diffusion parameters, which may accompany or alter the effect of intrinsic T2 in causing such dependence. The TE dependence may potentially serve as a biomarker for demyelination processes (e.g., in multiple sclerosis and Alzheimer's disease). Magn Reson Med 79:1650-1660, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  16. Leader-member exchange and affective organizational commitment: the contribution of supervisor's organizational embodiment.

    Science.gov (United States)

    Eisenberger, Robert; Karagonlar, Gokhan; Stinglhamber, Florence; Neves, Pedro; Becker, Thomas E; Gonzalez-Morales, M Gloria; Steiger-Mueller, Meta

    2010-11-01

    In order to account for wide variation in the relationship between leader-member exchange and employees' affective organizational commitment, we propose a concept termed supervisor's organizational embodiment (SOE), which involves the extent to which employees identify their supervisor with the organization. With samples of 251 social service employees in the United States (Study 1) and 346 employees in multiple Portuguese organizations (Study 2), we found that as SOE increased, the association between leader-member exchange and affective organizational commitment became greater. This interaction carried through to in-role and extra-role performance. With regard to antecedents, we found in Study 1 that supervisor's self-reported identification with the organization increased supervisor's expression of positive statements about the organization, which in turn increased subordinates' SOE. (c) 2010 APA, all rights reserved.

  17. Time dependency of psychotherapeutic exchanges: the contribution of the theory of dynamic systems in analyzing process.

    Science.gov (United States)

    Salvatore, Sergio; Tschacher, Wolfgang

    2012-01-01

    This paper provides a general framework for the use of Theory of Dynamic Systems (TDS) in the field of psychotherapy research. Psychotherapy is inherently dynamic, namely a function of time. Consequently, the improvement of construct validity and clinical relevance of psychotherapy process research require the development of models of investigation allowing dynamic mappings of clinical exchange. Thus, TDS becomes a significant theoretical and methodological reference. The paper focuses two topics. First, the main concepts of TDS are briefly introduced together with a basic typology of approaches developed within this domain. Second, we propose a repertoire of investigation strategies that can be used to capture the dynamic nature of clinical exchange. In this way we intend to highlight the feasibility and utility of strategies of analysis informed by TDS.

  18. Time dependency of psychotherapeutic exchanges: The contribution of the Theory of Dynamic Systems in analyzing process

    Directory of Open Access Journals (Sweden)

    Sergio eSalvatore

    2012-07-01

    Full Text Available This paper provides a general framework for the use of TDS in the field of psychotherapy research. Psychotherapy is inherently dynamic, namely a function of time. Consequently, the improvement of construct validity and clinical relevance of psychotherapy process research require the development of models of investigation allowing dynamic mappings of clinical exchange. Thus, the Theory of Dynamic Systems (TDS becomes a significant theoretical and methodological reference. The paper focuses two topics. First, the main concepts of TDS are briefly introduced together with a basic typology of approaches developed within this domain. Second, we propose a repertoire of investigation strategies that can be used to capture the dynamic nature of clinical exchange. In this way we intend to highlight the feasibility and utility of strategies of analysis informed by TDS.

  19. Diversity of Gender and Formation of Ingroup: a Contribution of Leader - Member Exchange Theory - LMX

    OpenAIRE

    Amaral, Derly Jardim do; Godoy, Arilda Schimidt; César, Ana Maria Roux Valentini Coelho; Silva, Adilson Aderito da

    2007-01-01

    The purpose of this article is to investigate the relationship between the Leader and Member Exchange Theory - LMX´s assumptions and the diversity of genders. To accomplish it, a questionnaire named LMX-MDM developed by Liden and Maslyn (1998) was used. The instrument is composed by 11 propositions that measures the multidimensionality of LMX. The questionnaire was submitted to a reversed translation process and was applied on a sample of students from Universidade Presbiteriana Mackenzie, lo...

  20. Can Leader–Member Exchange Contribute to Safety Performance in An Italian Warehouse?

    Science.gov (United States)

    Mariani, Marco G.; Curcuruto, Matteo; Matic, Mirna; Sciacovelli, Paolo; Toderi, Stefano

    2017-01-01

    Introduction: The research considers safety climate in a warehouse and wants to analyze the Leader–Member Exchange (LMX) role in respect to safety performance. Griffin and Neal’s safety model was adopted and Leader-Member Exchange was inserted as moderator in the relationships between safety climate and proximal antecedents (motivation and knowledge) of safety performance constructs (compliance and participation). Materials and Methods: Survey data were collected from a sample of 133 full-time employees in an Italian warehouse. The statistical framework of Hayes (2013) was adopted for moderated mediation analysis. Results: Proximal antecedents partially mediated the relationship between Safety climate and safety participation, but not safety compliance. Moreover, the results from the moderation analysis showed that the Leader–Member Exchange moderated the influence of safety climate on proximal antecedents and the mediation exist only at the higher level of LMX. Conclusion: The study shows that the different aspects of leadership processes interact in explaining individual proficiency in safety practices. Practical Implications: Organizations as warehouses should improve the quality of the relationship between a leader and a subordinate based upon the dimensions of respect, trust, and obligation for high level of safety performance. PMID:28553244

  1. Can Leader–Member Exchange Contribute to Safety Performance in An Italian Warehouse?

    Directory of Open Access Journals (Sweden)

    Marco G. Mariani

    2017-05-01

    Full Text Available Introduction: The research considers safety climate in a warehouse and wants to analyze the Leader–Member Exchange (LMX role in respect to safety performance. Griffin and Neal’s safety model was adopted and Leader-Member Exchange was inserted as moderator in the relationships between safety climate and proximal antecedents (motivation and knowledge of safety performance constructs (compliance and participation.Materials and Methods: Survey data were collected from a sample of 133 full-time employees in an Italian warehouse. The statistical framework of Hayes (2013 was adopted for moderated mediation analysis.Results: Proximal antecedents partially mediated the relationship between Safety climate and safety participation, but not safety compliance. Moreover, the results from the moderation analysis showed that the Leader–Member Exchange moderated the influence of safety climate on proximal antecedents and the mediation exist only at the higher level of LMX.Conclusion: The study shows that the different aspects of leadership processes interact in explaining individual proficiency in safety practices.Practical Implications: Organizations as warehouses should improve the quality of the relationship between a leader and a subordinate based upon the dimensions of respect, trust, and obligation for high level of safety performance.

  2. Can Leader-Member Exchange Contribute to Safety Performance in An Italian Warehouse?

    Science.gov (United States)

    Mariani, Marco G; Curcuruto, Matteo; Matic, Mirna; Sciacovelli, Paolo; Toderi, Stefano

    2017-01-01

    Introduction: The research considers safety climate in a warehouse and wants to analyze the Leader-Member Exchange (LMX) role in respect to safety performance. Griffin and Neal's safety model was adopted and Leader-Member Exchange was inserted as moderator in the relationships between safety climate and proximal antecedents (motivation and knowledge) of safety performance constructs (compliance and participation). Materials and Methods: Survey data were collected from a sample of 133 full-time employees in an Italian warehouse. The statistical framework of Hayes (2013) was adopted for moderated mediation analysis. Results: Proximal antecedents partially mediated the relationship between Safety climate and safety participation, but not safety compliance. Moreover, the results from the moderation analysis showed that the Leader-Member Exchange moderated the influence of safety climate on proximal antecedents and the mediation exist only at the higher level of LMX. Conclusion: The study shows that the different aspects of leadership processes interact in explaining individual proficiency in safety practices. Practical Implications: Organizations as warehouses should improve the quality of the relationship between a leader and a subordinate based upon the dimensions of respect, trust, and obligation for high level of safety performance.

  3. Effect of synthesis parameters and ion exchange on crystallinity and morphology of EU-1 zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Mohamed H.M.; Muraza, Oki, E-mail: omuraza@kfupm.edu.sa; Al Amer, Adnan M.

    2014-12-25

    Highlights: • Prolonged aging time to 12 h favored the phase purity and crystallinity of EU-1. • The optimum synthesis temperature to get highly crystalline EU-1 is 190 °C. • Minimum synthesis time at 190 °C is 72 h. • Metal ion exchange reduced the crystallinity of EU-1 crystals. - Abstract: The effect of aging time, synthesis temperature and synthesis time on crystallinity and morphology of Na–EU-1 has been studied. Hexamethonium bromide was used as a template to synthesize Na–EU-1 zeolite with Si/Al of 25. In addition, the effect of modification using ion exchange with (NH{sub 4}{sup +}, Ca{sup 2+}, Li{sup +} and Ni{sup +}) nitrates to replace Na{sup +} was also studied. X-ray diffraction was used to study the phases and the crystallinity of zeolite crystals. Morphology of EU-1 crystals was observed using scanning electron microscope (SEM). Prolonged aging time up to 12 h favored pure phase and crystalline EU-1. It has been found that the optimum synthesis temperature to obtain highly crystalline EU-1 is 190 °C. The shortest synthesis time to obtain crystalline EU-1 at 190 °C is 72 h. Ion exchange reduced the crystallinity of EU-1 crystals. We anticipate that the metal-modified EU-1 is a potential catalyst in numerous reactions such as isomerization and methanol-to-hydrocarbon.

  4. Understanding on Interface Contribution to the Electrode Performance of Proton Exchange Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma; Grahl-Madsen, L.

    2016-01-01

    The commercialization of proton exchange membrane fuel cells (PEMFCs) is closer to the reality than ever before. Electrode interface development can bring a boost to the last few steps. Here, we explore electrode properties from its interface structure, especially the ionomer phase. Electrodes...... decreased with the increase of the ionomer. The electrode surface studies surprisingly reveal that the ionomer coverage increases linearly with the ionomer loading/content only up to a certain extent (around 30 wt.% in this case); further increase of the ionomer content triggers ionomer agglomeration, which...

  5. Electrostatic contributions to protein retention in ion-exchange chromatography. 1. Cytochrome C variants.

    Science.gov (United States)

    Yao, Yan; Lenhoff, Abraham M

    2004-11-15

    Among the factors that modulate protein interactions, several protein structural properties, such as size, shape, and charge distribution, may play significant roles. In this work, we investigate the influence of protein structure on binding in ion-exchange chromatography, in which electrostatic interactions are dominant. Chromatographic experiments show separation of cytochrome c variants with a limited number of sequence differences to be feasible. To probe the molecular basis for this behavior, protein-adsorbent electrostatic interactions were modeled in the context of continuum electrostatics accounting for the full 3D protein structure. Protein retention was modeled by averaging over all protein-adsorbent configurations using the full accessible surface of the protein. The electrostatic interaction free energy distribution shows that configurations in which numerous positive protein charges are close to the cation exchanger functional groups produce the most favorable binding. The calculated binding equilibrium constant, found by averaging over the full 3D configurational space, captures the chromatographic differentiation of closely related cytochrome c variants. To obviate the need for full sampling of protein configurations, calculations of interaction free energies at short protein-adsorbent separation distances or of protein surface potentials were found to yield reasonable semiquantitative descriptions of the retention trends.

  6. A quark model calculation for the short-range contribution in the pion double charge exchange reaction

    Energy Technology Data Exchange (ETDEWEB)

    Zou Bingsong; Jiang Huanqing (Institute of Theoretical Physics and Institute of High Energy Physcis, Academia Sinica, Beijing (CN))

    1989-10-01

    A quark model calculation for the short-range contribution in the pion double charge exchange (DCX) reaction is presented. In the framework of this new model the angular distributions of {sup 18}O({pi}{sup +},{pi}{sup {minus}}){sup 18}Ne(g.s.) at low energies are calculated and compared with the experimental data. It is found that this model can explain the anomalous'' increasing behavior for the DCX reaction around 50 MeV quite well.

  7. Contributions of rapid neuromuscular transmission to the fine control of acoustic parameters of birdsong.

    Science.gov (United States)

    Mencio, Caitlin; Kuberan, Balagurunathan; Goller, Franz

    2017-02-01

    Neural control of complex vocal behaviors, such as birdsong and speech, requires integration of biomechanical nonlinearities through muscular output. Although control of airflow and tension of vibrating tissues are known functions of vocal muscles, it remains unclear how specific muscle characteristics contribute to specific acoustic parameters. To address this gap, we removed heparan sulfate chains using heparitinases to perturb neuromuscular transmission subtly in the syrinx of adult male zebra finches (Taeniopygia guttata). Infusion of heparitinases into ventral syringeal muscles altered their excitation threshold and reduced neuromuscular transmission changing their ability to modulate airflow. The changes in muscle activation dynamics caused a reduction in frequency modulation rates and elimination of many high-frequency syllables but did not alter the fundamental frequency of syllables. Sound amplitude was reduced and sound onset pressure was increased, suggesting a role of muscles in the induction of self-sustained oscillations under low-airflow conditions, thus enhancing vocal efficiency. These changes were reversed to preinfusion levels by 7 days after infusion. These results illustrate complex interactions between the control of airflow and tension and further define the importance of syringeal muscle in the control of a variety of acoustic song characteristics. In summary, the findings reported here show that altering neuromuscular transmission can lead to reversible changes to the acoustic structure of song. Understanding the full extent of muscle involvement in song production is critical in decoding the motor program for the production of complex vocal behavior, including our search for parallels between birdsong and human speech motor control. It is largely unknown how fine motor control of acoustic parameters is achieved in vocal organs. Subtle manipulation of syringeal muscle function was used to test how active motor control influences acoustic

  8. Search for a two-photon exchange contribution to inclusive deep-inelastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Airapetian, A. [Giessen Univ. (Germany). Physikalisches Institut; Michigan Univ., Ann Arbor (United States). Randall Lab. of Physics; Akopov, N. [Yerevan Physics Institute (Argentina); Akopov, Z. [DESY Hamburg (DE)] (and others)

    2009-07-15

    The transverse-target single-spin asymmetry for inclusive deep-inelastic scattering with effectively unpolarized electron and positron beams off a transversely polarized hydrogen target was measured, with the goal of searching for a two-photon exchange signal in the kinematic range 0.0071 GeV{sup 2} and Q{sup 2}<1 GeV{sup 2}, and for both electron and positron beams, the asymmetries are found to be consistent with zero within statistical and systematic uncertainties, which are of order 10{sup -3} for the asymmetries integrated over x{sub B}. (orig.)

  9. An Excel tool for deriving key photosynthetic parameters from combined gas exchange and chlorophyll fluorescence: theory and practice.

    Science.gov (United States)

    Bellasio, Chandra; Beerling, David J; Griffiths, Howard

    2016-06-01

    Combined photosynthetic gas exchange and modulated fluorometres are widely used to evaluate physiological characteristics associated with phenotypic and genotypic variation, whether in response to genetic manipulation or resource limitation in natural vegetation or crops. After describing relatively simple experimental procedures, we present the theoretical background to the derivation of photosynthetic parameters, and provide a freely available Excel-based fitting tool (EFT) that will be of use to specialists and non-specialists alike. We use data acquired in concurrent variable fluorescence-gas exchange experiments, where A/Ci and light-response curves have been measured under ambient and low oxygen. From these data, the EFT derives light respiration, initial PSII (photosystem II) photochemical yield, initial quantum yield for CO2 fixation, fraction of incident light harvested by PSII, initial quantum yield for electron transport, electron transport rate, rate of photorespiration, stomatal limitation, Rubisco (ribulose 1·5-bisphosphate carboxylase/oxygenase) rate of carboxylation and oxygenation, Rubisco specificity factor, mesophyll conductance to CO2 diffusion, light and CO2 compensation point, Rubisco apparent Michaelis-Menten constant, and Rubisco CO2 -saturated carboxylation rate. As an example, a complete analysis of gas exchange data on tobacco plants is provided. We also discuss potential measurement problems and pitfalls, and suggest how such empirical data could subsequently be used to parameterize predictive photosynthetic models. © 2015 John Wiley & Sons Ltd.

  10. How behavioural science can contribute to health partnerships: the case of The Change Exchange.

    Science.gov (United States)

    Byrne-Davis, Lucie M T; Bull, Eleanor R; Burton, Amy; Dharni, Nimarta; Gillison, Fiona; Maltinsky, Wendy; Mason, Corina; Sharma, Nisha; Armitage, Christopher J; Johnston, Marie; Byrne, Ged J; Hart, Jo K

    2017-06-12

    Health partnerships often use health professional training to change practice with the aim of improving quality of care. Interventions to change practice can learn from behavioural science and focus not only on improving the competence and capability of health professionals but also their opportunity and motivation to make changes in practice. We describe a project that used behavioural scientist volunteers to enable health partnerships to understand and use the theories, techniques and assessments of behavioural science. This paper outlines how The Change Exchange, a collective of volunteer behavioural scientists, worked with health partnerships to strengthen their projects by translating behavioural science in situ. We describe three case studies in which behavioural scientists, embedded in health partnerships in Uganda, Sierra Leone and Mozambique, explored the behaviour change techniques used by educators, supported knowledge and skill development in behaviour change, monitored the impact of projects on psychological determinants of behaviour and made recommendations for future project developments. Challenges in the work included having time and space for behavioural science in already very busy health partnership schedules and the difficulties in using certain methods in other cultures. Future work could explore other modes of translation and further develop methods to make them more culturally applicable. Behavioural scientists could translate behavioural science which was understood and used by the health partnerships to strengthen their project work.

  11. Bromodeoxyuridine does not contribute to sister chromatid exchange events in normal or Bloom syndrome cells.

    Science.gov (United States)

    van Wietmarschen, Niek; Lansdorp, Peter M

    2016-08-19

    Sister chromatid exchanges (SCEs) are considered sensitive indicators of genome instability. Detection of SCEs typically requires cells to incorporate bromodeoxyuridine (BrdU) during two rounds of DNA synthesis. Previous studies have suggested that SCEs are induced by DNA replication over BrdU-substituted DNA and that BrdU incorporation alone could be responsible for the high number of SCE events observed in cells from patients with Bloom syndrome (BS), a rare genetic disorder characterized by marked genome instability and high SCE frequency. Here we show using Strand-seq, a single cell DNA template strand sequencing technique, that the presence of variable BrdU concentrations in the cell culture medium and in DNA template strands has no effect on SCE frequency in either normal or BS cells. We conclude that BrdU does not induce SCEs and that SCEs detected in either normal or BS cells reflect DNA repair events that occur spontaneously. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  12. [Sister chromatid exchanges and chromosome aberrations as parameters for human risk of cancer development].

    Science.gov (United States)

    Morimoto, K

    1987-04-01

    Chromosome alterations, which are directly visible changes in the DNA, have close associations to cancer development, non-specific ageing, and heritable genetic status. Human lymphocyte cultures can be used for cytogenetic monitoring of genetic health because many cancers and genetic effects are caused by long-term unhealthy life-styles. We have investigated the sensitivities of lymphocytes from inherited-cancer-prone diseases to the induction of the chromosome alterations by mutagens and carcinogens, and the correlations between the frequency of sister chromatid exchanges (SCEs) in peripheral lymphocytes and life-styles or daily ways of living. Lymphocytes from patients with Down syndrome, Fanconi anemia, xeroderma pigmentosum, ataxia telangiectasia, and Bloom syndromes showed altered (usually enhanced) susceptibilities to the induction of chromosome aberrations and SCEs by mutagens and carcinogens in our environments. Mean frequencies of baseline SCEs in lymphocytes from normal men with poor life-styles have also been shown to be significantly higher than those in cells from men having good life-styles. The former cells have further been shown to have hyper sensitivities to the induction of SCEs by mitomycin-C' treatment compared to latter cells. Unhealthy life-styles also make the lymphocytes to be more sensitive to ara-C's enhancement of radiation-induced chromosome aberrations.

  13. Significant contribution from foliage-derived ABA in regulating gas exchange in Pinus radiata.

    Science.gov (United States)

    Mitchell, Patrick J; McAdam, Scott A M; Pinkard, Elizabeth A; Brodribb, Timothy J

    2017-02-01

    The complex regulatory system controlling stomata involves physical and chemical signals that affect guard cell turgor to bring about changes in stomatal conductance (gs). Abscisic acid (ABA) closes stomata, yet the mechanisms controlling foliar ABA status in tree species remain unclear. The importance of foliage-derived ABA in regulating gas exchange was evaluated under treatments that affected phloem export through girdling and reduced water availability in the tree species, Pinus radiata (D. Don). Branch- and whole-plant girdling increased foliar ABA levels leading to declines in gs, despite no change in plant water status. Changes in gs were largely independent of the more transient increases in foliar non-structural carbohydrates (NSC), suggesting that gradual accumulation of foliar ABA was the primary mechanism for reductions in gs and assimilation. Whole-plant girdling eventually reduced root NSC, hindering root water uptake and decreasing foliar water potential, causing a dramatic increase in ABA level in leaves and concentrations in the xylem sap of shoots (4032 ng ml-1), while root xylem sap concentrations remained low (43 ng ml-1). Contrastingly, the drought treatment caused similar increases in xylem sap ABA in both roots and shoots, suggesting that declines in water potential result in relatively consistent changes in ABA along the hydraulic pathway. ABA levels in plant canopies can be regulated independently of changes in root water status triggered by changes by both phloem export and foliar water status. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Strength of Selection Pressure Is an Important Parameter Contributing to the Complexity of Antibiotic Resistance Evolution

    Science.gov (United States)

    Oz, Tugce; Guvenek, Aysegul; Yildiz, Sadik; Karaboga, Enes; Tamer, Yusuf Talha; Mumcuyan, Nirva; Ozan, Vedat Burak; Senturk, Gizem Hazal; Cokol, Murat; Yeh, Pamela; Toprak, Erdal

    2014-01-01

    Revealing the genetic changes responsible for antibiotic resistance can be critical for developing novel antibiotic therapies. However, systematic studies correlating genotype to phenotype in the context of antibiotic resistance have been missing. In order to fill in this gap, we evolved 88 isogenic Escherichia coli populations against 22 antibiotics for 3 weeks. For every drug, two populations were evolved under strong selection and two populations were evolved under mild selection. By quantifying evolved populations’ resistances against all 22 drugs, we constructed two separate cross-resistance networks for strongly and mildly selected populations. Subsequently, we sequenced representative colonies isolated from evolved populations for revealing the genetic basis for novel phenotypes. Bacterial populations that evolved resistance against antibiotics under strong selection acquired high levels of cross-resistance against several antibiotics, whereas other bacterial populations evolved under milder selection acquired relatively weaker cross-resistance. In addition, we found that strongly selected strains against aminoglycosides became more susceptible to five other drug classes compared with their wild-type ancestor as a result of a point mutation on TrkH, an ion transporter protein. Our findings suggest that selection strength is an important parameter contributing to the complexity of antibiotic resistance problem and use of high doses of antibiotics to clear infections has the potential to promote increase of cross-resistance in clinics. PMID:24962091

  15. Contribution of thermal infrared images on the understanding of the subsurface/atmosphere exchanges on Earth.

    Science.gov (United States)

    Lopez, Teodolina; Antoine, Raphaël; Baratoux, David; Rabinowicz, Michel

    2017-04-01

    High temporal resolution of space-based thermal infrared images (METEOSAT, MODIS) and the development of field thermal cameras have permitted the development of thermal remote sensing in Earth Sciences. Thermal images are influenced by many factors such as atmosphere, solar radiation, topography and physico-chemical properties of the surface. However, considering these limitations, we have discovered that thermal images can be used in order to better understand subsurface hydrology. In order to reduce as much as possible the impact of these perturbing factors, our approach combine 1) field observations and 2) numerical modelling of surface/subsurface thermal processes. Thermal images of the Piton de la Fournaise volcano (Réunion Island), acquired by hand, show that the Formica Leo inactive scoria cone and some fractures close to the Bory-Dolomieu caldera are always warmer, inducing a thermal difference with the surrounding of at least 5°C and a Self-Potential anomaly [1, 2]. Topography cannot explain this thermal behaviour, but Piton de la Fournaise is known as highly permeable. This fact allows the development of an air convection within the whole permeable structure volcanic edifice [2]. Cold air enters the base of the volcano, and exits warmer upslope, as the air is warmed by the geothermal flow [1,2]. Then, we have decided to understand the interaction between subsurface hydrogeological flows and the humidity in the atmosphere. In the Lake Chad basin, regions on both sides of Lake Chad present a different thermal behaviour during the diurnal cycle and between seasons [3]. We propose that this thermal behaviour can only be explained by lateral variations of the surface permeability that directly impact the process of evaporation/condensation cycle. These studies bring new highlights on the understanding of the exchanges between subsurface and the atmosphere, as the presence of a very permeable media and/or variations of the surface permeability may enhance or

  16. IgE sensitisation in relation to flow-independent nitric oxide exchange parameters

    Directory of Open Access Journals (Sweden)

    Norbäck Dan

    2006-06-01

    Full Text Available Abstract Background A positive association between IgE sensitisation and exhaled NO levels has been found in several studies, but there are no reports on the compartment of the lung that is responsible for the increase in exhaled NO levels seen in IgE-sensitised subjects. Methods The present study comprised 288 adult subjects from the European Community Respiratory Health Survey II who were investigated in terms of lung function, IgE sensitisation (sum of specific IgE, smoking history and presence of rhinitis and asthma. Mean airway tissue concentration of NO (CawNO, airway transfer factor for NO (DawNO, mean alveolar concentration of NO (CalvNO and fractional exhaled concentration of NO at a flow rate of 50 mL s-1 (FENO 0.05 were determined using the extended NO analysis. Results IgE-sensitised subjects had higher levels (geometric mean of FENO 0.05 (24.9 vs. 17.3 ppb (p NO (10.5 vs. 8 mL s-1 (p = 0.02 and CawNO (124 vs. 107 ppb (p NO 0.05, CawNO and DawNO levels (p Conclusion The presence of IgE sensitisation and the degree of allergic sensitisation were related to the increase in airway NO transfer factor and the increase in NO concentration in the airway wall. Sensitisation to cat allergen was related to the highest increases in exhaled NO parameters. Our data suggest that exhaled NO is more a specific marker of allergic inflammation than a marker of asthma or rhinitis.

  17. Estimate the contribution of incubation parameters influence egg hatchability using multiple linear regression analysis

    OpenAIRE

    Khalil, Mohamed H.; Shebl, Mostafa K.; Kosba, Mohamed A.; El-Sabrout, Karim; Zaki, Nesma

    2016-01-01

    Aim: This research was conducted to determine the most affecting parameters on hatchability of indigenous and improved local chickens’ eggs. Materials and Methods: Five parameters were studied (fertility, early and late embryonic mortalities, shape index, egg weight, and egg weight loss) on four strains, namely Fayoumi, Alexandria, Matrouh, and Montazah. Multiple linear regression was performed on the studied parameters to determine the most influencing one on hatchability. Results: The...

  18. Purification of Monoclonal Antibodies Using a Fiber Based Cation-Exchange Stationary Phase: Parameter Determination and Modeling

    Directory of Open Access Journals (Sweden)

    Jan Schwellenbach

    2016-10-01

    Full Text Available Monoclonal antibodies (mAb currently dominate the market for protein therapeutics. Because chromatography unit operations are critical for the purification of therapeutic proteins, the process integration of novel chromatographic stationary phases, driven by the demand for more economic process schemes, is a field of ongoing research. Within this study it was demonstrated that the description and prediction of mAb purification on a novel fiber based cation-exchange stationary phase can be achieved using a physico-chemical model. All relevant mass-transport phenomena during a bind and elute chromatographic cycle, namely convection, axial dispersion, boundary layer mass-transfer, and the salt dependent binding behavior in the fiber bed were described. This work highlights the combination of model adaption, simulation, and experimental parameter determination through separate measurements, correlations, or geometric considerations, independent from the chromatographic cycle. The salt dependent binding behavior of a purified mAb was determined by the measurement of adsorption isotherms using batch adsorption experiments. Utilizing a combination of size exclusion and protein A chromatography as analytic techniques, this approach can be extended to a cell culture broth, describing the salt dependent binding behavior of multiple components. Model testing and validation was performed with experimental bind and elute cycles using purified mAb as well as a clarified cell culture broth. A comparison between model calculations and experimental data showed a good agreement. The influence of the model parameters is discussed in detail.

  19. The use of laboratory-determined ion exchange parameters in the predictive modelling of field-scale major cation migration in groundwater over a 40-year period.

    Science.gov (United States)

    Carlyle, Harriet F; Tellam, John H; Parker, Karen E

    2004-01-01

    An attempt has been made to estimate quantitatively cation concentration changes as estuary water invades a Triassic Sandstone aquifer in northwest England. Cation exchange capacities and selectivity coefficients for Na(+), K(+), Ca(2+), and Mg(2+) were measured in the laboratory using standard techniques. Selectivity coefficients were also determined using a method involving optimized back-calculation from flushing experiments, thus permitting better representation of field conditions; in all cases, the Gaines-Thomas/constant cation exchange capacity (CEC) model was found to be a reasonable, though not perfect, first description. The exchange parameters interpreted from the laboratory experiments were used in a one-dimensional reactive transport mixing cell model, and predictions compared with field pumping well data (Cl and hardness spanning a period of around 40 years, and full major ion analyses in approximately 1980). The concentration patterns predicted using Gaines-Thomas exchange with calcite equilibrium were similar to the observed patterns, but the concentrations of the divalent ions were significantly overestimated, as were 1980 sulphate concentrations, and 1980 alkalinity concentrations were underestimated. Including representation of sulphate reduction in the estuarine alluvium failed to replicate 1980 HCO(3) and pH values. However, by including partial CO(2) degassing following sulphate reduction, a process for which there is 34S and 18O evidence from a previous study, a good match for SO(4), HCO(3), and pH was attained. Using this modified estuary water and averaged values from the laboratory ion exchange parameter determinations, good predictions for the field cation data were obtained. It is concluded that the Gaines-Thomas/constant exchange capacity model with averaged parameter values can be used successfully in ion exchange predictions in this aquifer at a regional scale and over extended time scales, despite the numerous assumptions inherent in

  20. Signal intensities derived from different NMR probes and parameters contribute to variations in quantification of metabolites.

    Directory of Open Access Journals (Sweden)

    Paige Lacy

    Full Text Available We discovered that serious issues could arise that may complicate interpretation of metabolomic data when identical samples are analyzed at more than one NMR facility, or using slightly different NMR parameters on the same instrument. This is important because cross-center validation metabolomics studies are essential for the reliable application of metabolomics to clinical biomarker discovery. To test the reproducibility of quantified metabolite data at multiple sites, technical replicates of urine samples were assayed by 1D-(1H-NMR at the University of Alberta and the University of Michigan. Urine samples were obtained from healthy controls under a standard operating procedure for collection and processing. Subsequent analysis using standard statistical techniques revealed that quantitative data across sites can be achieved, but also that previously unrecognized NMR parameter differences can dramatically and widely perturb results. We present here a confirmed validation of NMR analysis at two sites, and report the range and magnitude that common NMR parameters involved in solvent suppression can have on quantitated metabolomics data. Specifically, saturation power levels greatly influenced peak height intensities in a frequency-dependent manner for a number of metabolites, which markedly impacted the quantification of metabolites. We also investigated other NMR parameters to determine their effects on further quantitative accuracy and precision. Collectively, these findings highlight the importance of and need for consistent use of NMR parameter settings within and across centers in order to generate reliable, reproducible quantified NMR metabolomics data.

  1. Towards the blackbox computation of magnetic exchange coupling parameters in polynuclear transition-metal complexes: theory, implementation, and application.

    Science.gov (United States)

    Phillips, Jordan J; Peralta, Juan E

    2013-05-07

    We present a method for calculating magnetic coupling parameters from a single spin-configuration via analytic derivatives of the electronic energy with respect to the local spin direction. This method does not introduce new approximations beyond those found in the Heisenberg-Dirac Hamiltonian and a standard Kohn-Sham Density Functional Theory calculation, and in the limit of an ideal Heisenberg system it reproduces the coupling as determined from spin-projected energy-differences. Our method employs a generalized perturbative approach to constrained density functional theory, where exact expressions for the energy to second order in the constraints are obtained by analytic derivatives from coupled-perturbed theory. When the relative angle between magnetization vectors of metal atoms enters as a constraint, this allows us to calculate all the magnetic exchange couplings of a system from derivatives with respect to local spin directions from the high-spin configuration. Because of the favorable computational scaling of our method with respect to the number of spin-centers, as compared to the broken-symmetry energy-differences approach, this opens the possibility for the blackbox exploration of magnetic properties in large polynuclear transition-metal complexes. In this work we outline the motivation, theory, and implementation of this method, and present results for several model systems and transition-metal complexes with a variety of density functional approximations and Hartree-Fock.

  2. Exchanged naturality contributions from high-energy polarization measurements in two-body inclusive and exclusive reactions

    CERN Document Server

    Ader, J P

    1974-01-01

    In the paper, dealing with high-energy quasi-two-body or multiparticle production, the authors focus on what can be learned about exchanged naturality amplitudes from final polarization measurements with polarized or unpolarized beam amd/or target. The separation of t- channel (boson exchange) and u-channel (baryon exchange) exchanges into components of natural and unnatural parity and the measure of naturality interferences are extensively studied in all cases which are now or will be soon available with present experimental techniques. Special attention is paid to the transversity amplitudes which are shown to be always naturality conserving. (19 refs).

  3. Manual blood exchange transfusion does not significantly contribute to parasite clearance in artesunate-treated individuals with imported severe Plasmodium falciparum malaria

    NARCIS (Netherlands)

    A.R. Kreeftmeijer-Vegter (Annemarie); M.M. de Melo (Mariana ); P.J. de Vries (Peter); R. Koelewijn (Rob); J.J. van Hellemond (Jaap); P.J.J. van Genderen (Perry)

    2013-01-01

    textabstractBackground: Exchange transfusion (ET) has remained a controversial adjunct therapy for the treatment of severe malaria. In order to assess the relative contribution of ET to parasite clearance in severe malaria, all patients receiving ET as an adjunct treatment to parenteral quinine or

  4. Analysis of the influence of climatic and physiological parameters on the net ecosystem carbon exchange of an apple orchard

    Science.gov (United States)

    Zanotelli, Damiano; Montagnani, Leonardo; Scandellari, Francesca; Tagliavini, Massimo

    2013-04-01

    Net ecosystem carbon exchange (NEE) of an apple orchard located in South Tyrol (Caldaro, Bolzano, Italy) was monitored continuously since March 2009 via eddy covariance technique. Contemporary measurements of the main environmental parameters (temperature, photosynthetic active photon flux density, soil water content, vapor pressure deficit) were taken at the same field site. Leaf Area Index was also determined biometrically starting from spring 2010. Objectives of this work were (i) to assess the influence of these environmental and physiological parameters on NEE, (ii) to set up a model capable to fill large gap occurring in the dataset and (iii) predict inter-annual variability of fluxes based on the measurements of the selected explanatory variables. Daily cumulated values of the response variable (NEE, g C d-1) and mean daily value of the five explanatory variables considered (air T, ° C; SWC, m3m-3; PPFD, μmol m-2s-1; VPD, hPa, LAI m2m-2) were used in this analysis. The complex interactions between the explanatory variables and NEE were analyzed with the tree model approach which draws a picture of the complexity of data structure and highlights the explanatory variable that explain the greater amount of deviance of the response variable. NEE variability was mostly explained by LAI and PPFD. The most positive values of NEE occurred below the LAI threshold of 1.16 m2m-2 while above that LAI threshold and with an average daily PPFD above 13.2 μmol m-2s-1, the orchard resulted always a sink of carbon (negative daily NEE). On half of the available data (only alternate months of the considered period were considered), a stepwise multiple regression approach was used to model NEE using the variables indicated above. Simplification by deletion of the non-significant terms was carried out until all parameters where highly significant (p analysis, the model was further improved by transforming the linear predictor. Akaikés Information Criterion (AIC) was used to

  5. EVALUATING THE CONTRIBUTION OF PHYSICAL PARAMETERS ON THE SAFETY OF UNSIGNALIZED INTERSECTIONS

    Directory of Open Access Journals (Sweden)

    A. AHMED

    2015-05-01

    Full Text Available Safety of any particular Road way facility cannot be attributed to set of parameters specific to a certain domain. Unsignalized intersections are no exceptions, thus, making them an important area of study. This paper presents the results of the analysis of four parameters, namely road width, traffic control, lane marking and landuse; and their sub-class on the safety of unsignalized intersections. The raw accident data was obtained from MIROS (Malaysian Institute of Road Safety Research. It was then reduced for descriptive analysis. Hypothesis testing was performed to assess the significance of all parameters and severity analysis was done to accomplish micro scale examination of each sub-class. The results show that landuse and lane marking are statistically significant. They are important variables to predict accidents whereas traffic control and road width are not significant. Intersections located in city with single line lane marking having no control and major road width greater than 9 meters were found to have the highest severity indices.

  6. Making sense of nonsense in British Sign Language (BSL): The contribution of different phonological parameters to sign recognition.

    Science.gov (United States)

    Orfanidou, Eleni; Adam, Robert; McQueen, James M; Morgan, Gary

    2009-04-01

    Do all components of a sign contribute equally to its recognition? In the present study, misperceptions in the sign-spotting task (based on the word-spotting task; Cutler & Norris, 1988) were analyzed to address this question. Three groups of deaf signers of British Sign Language (BSL) with different ages of acquisition (AoA) saw BSL signs combined with nonsense signs, along with combinations of two nonsense signs. They were asked to spot real signs and report what they had spotted. We will present an analysis of false alarms to the nonsense-sign combinations-that is, misperceptions of nonsense signs as real signs (cf. van Ooijen, 1996). Participants modified the movement and handshape parameters more than the location parameter. Within this pattern, however, there were differences as a function of AoA. These results show that the theoretical distinctions between form-based parameters in sign-language models have consequences for online processing. Vowels and consonants have different roles in speech recognition; similarly, it appears that movement, handshape, and location parameters contribute differentially to sign recognition.

  7. Electric control of exchange bias training.

    Science.gov (United States)

    Echtenkamp, W; Binek, Ch

    2013-11-01

    Voltage-controlled exchange bias training and tunability are introduced. Isothermal voltage pulses are used to reverse the antiferromagnetic order parameter of magnetoelectric Cr(2)O(3), and thus continuously tune the exchange bias of an adjacent CoPd film. Voltage-controlled exchange bias training is initialized by tuning the antiferromagnetic interface into a nonequilibrium state incommensurate with the underlying bulk. Interpretation of these hitherto unreported effects contributes to new understanding in electrically controlled magnetism.

  8. The effect of the application of the biological control agent EM1 on gas exchange parameters and productivity of Pisum sativum L. infected with Fusarium oxysporum Schlecht.

    OpenAIRE

    Adam Okorski; Jacek Olszewski; Katarzyna Głowacka; Sylwia Okorska; Agnieszka Pszczółkowska

    2012-01-01

    A pot experiment on different methods of EM 1 application was conducted in the period 2002-2004. The study was carried out under controlled growth conditions. The experimental factor was the method of EM1 application. Before application, the biological preparation EM1 was propagated as recommended by the manufacturer (Greenland). The health status of the aboveground parts of 'Ramrod' pea plants was estimated at the flowering stage. The assessment of pea leaf gas exchange parameters (An, E, Gs...

  9. European contribution to heat exchanger design/performance: HTFS research and computer programs. Final report. [SCON4 and CEMP1

    Energy Technology Data Exchange (ETDEWEB)

    Lang, C.; Skrovanek, T.

    1979-01-01

    The performance of selected HTFS computer program in solving example heat exchanger design/performance situations is evaluated. In addition, the specific inputs required by the program are presented to give an idea of the amount of detail the user must supply concerning the heat transfer system. Comments on the versatility of each program and technical details necessary for running each program are also provided. The computer programs examined rate the performance of shell-and-tube type condensers and plate-fin heat exchangers.

  10. Effect of some geometric parameters on performance of PF{sup 2} heat exchangers in periodic frosting

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ping [Zhejiang Vocational College of Commerce, Hangzhou, Binwen Road 470 (China); Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801 (United States); Hrnjak, P.S. [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801 (United States)

    2010-03-15

    The thermal performance under conditions of initial frost growth and subsequent refrosting after a defrost is experimentally studied for the parallel flow parallel fin (PF{sup 2}) heat exchanger, a new style of heat exchanger that uses louvered bent fins on flat tubes to enhance water drainage when the flat tubes are horizontal (typically outdoor heat exchanger in heat pump operation). This paper focuses on quantification of the effects of geometry (i.e. fin pitch 12-22 fpi and louver pitch 1.4-2.8 mm) on defrost and refrost times. Eight heat exchangers differing in louver pitch and fin spacing are studied. A series of tests are conducted in search for the best geometry. The effects of geometry on heat transfer (thermal performance) and pressure drop for air face velocities of 0.9, 2, and 3 m/s are determined and used for comparison. Characteristics of initial heat transfer coefficient and pressure drop during the first frosting cycle are reported in terms of Colburn j{sub 0} factor and Fanning friction f{sub 0} factor, as a function of Re{sub L{sub p}} and geometry. The newly developed air-side correlations for PF{sup 2} heat exchangers (Colburn j{sub 0} factor and Fanning friction f{sub 0} factor) predict the test data within rms error of {+-}10%, and with mean deviation of 2.95% and 4.98%, respectively. The correlations are base on a very low Reynolds numbers in the range of 100-620, and 8 PF{sup 2} heat exchangers using 48 experimental data. (author)

  11. Analysis of parameter sensitivity on surface heat exchange in the Noah land surface model at a temperate desert steppe site in China

    Science.gov (United States)

    Zhang, Guo; Zhou, Guangsheng; Chen, Fei

    2017-12-01

    The dominant parameters in the Noah land surface model (LSM) are identified, and the effects of parameter optimization on the surface heat exchange are investigated at a temperate desert steppe site during growing season in Inner Mongolia, China. The relative impacts of parameters on surface heat flux are examined by the distributed evaluation of local sensitivity analysis (DELSA), and the Noah LSM is calibrated by the global shuffled complex evolution (SCE) against the corresponding observations during May-September of 2008 and 2009. The differences in flux simulations are assessed between the Noah LSM calibrated by the SCE with 27 parameters and 12 dominant parameters. The systematic error, unsystematic error, root mean squared error, and mean squared error decompositions are used to evaluate the model performance. Compared to the control experiment, parameter optimization by the SCE using net radiation, sensible heat flux, latent heat flux, and ground heat flux as the objective criterion, respectively, can obviously reduce the errors of the Noah LSM. The calibrated Noah LSM is further validated against flux observations of growing season in 2010, and it is found that the calibrated Noah LSM can be applied in the longer term at this site. The Noah LSM with 12 dominant parameters calibrated performs similar to that with 27 parameters calibrated.

  12. Sea ice contribution to the air-sea CO{sub 2} exchange in the Arctic and Southern Oceans

    Energy Technology Data Exchange (ETDEWEB)

    Rysgaard, Soeren (Greenland Climate Research Centre, Greenland Inst. of Natural Resources, Nuuk, Greenland (Denmark); Centre for Earth Observation Science, CHR Faculty of Environment Earth and Resources, Univ. of Manitoba, Winnipeg (Canada)), e-mail: rysgaard@natur.gl; Bendtsen, Joergen (Greenland Climate Research Centre, Greenland Inst. of Natural Resources, Nuuk, Greenland (Denmark); Centre for Ice and Climate, Niels Bohr Inst., Univ. of Copenhagen, Copenhagen O (Denmark)); Delille, Bruno (Unit' e d' Oceanographie Chimique, Interfacultary Centre for Marine Research, Universite de Liege, Liege (Belgium)); Dieckmann, Gerhard S. (Alfred Wegener Inst. for Polar and Marine Research, Bremerhaven (Germany)); Glud, Ronnie N. (Greenland Climate Research Centre, Greenland Inst. of Natural Resources, Nuuk, Greenland (Denmark); Scottish Association of Marine Sciences, Scotland UK, Southern Danish Univ. and NordCee, Odense M (Denmark)); Kennedy, Hilary; Papadimitriou, Stathys (School of Ocean Sciences, Bangor Univ., Menai Bridge, Anglesey, Wales (United Kingdom)); Mortensen, John (Greenland Climate Research Centre, Greenland Inst. of Natural Resources, Nuuk, Greenland (Denmark)); Thomas, David N. (School of Ocean Sciences, Bangor Univ., Menai Bridge, Anglesey, Wales (United Kingdom); Finnish Environment Inst. (SYKE), Marine Research Centre, Helsinki (Finland)); Tison, Jean-Louis (Glaciology Unit, Dept. of Earth and Environmental Sciences, Universite Libre de Bruxelles, Bruxelles, (Belgium))

    2011-11-15

    Although salt rejection from sea ice is a key process in deep-water formation in ice-covered seas, the concurrent rejection of CO{sub 2} and the subsequent effect on air-sea CO{sub 2} exchange have received little attention. We review the mechanisms by which sea ice directly and indirectly controls the air-sea CO{sub 2} exchange and use recent measurements of inorganic carbon compounds in bulk sea ice to estimate that oceanic CO{sub 2} uptake during the seasonal cycle of sea-ice growth and decay in ice-covered oceanic regions equals almost half of the net atmospheric CO{sub 2} uptake in ice-free polar seas. This sea-ice driven CO{sub 2} uptake has not been considered so far in estimates of global oceanic CO{sub 2} uptake. Net CO{sub 2} uptake in sea-ice-covered oceans can be driven by; (1) rejection during sea-ice formation and sinking of CO{sub 2}-rich brine into intermediate and abyssal oceanic water masses, (2) blocking of air-sea CO{sub 2} exchange during winter, and (3) release of CO{sub 2}-depleted melt water with excess total alkalinity during sea-ice decay and (4) biological CO{sub 2} drawdown during primary production in sea ice and surface oceanic waters

  13. Sea ice contribution to the air-sea CO(2) exchange in the Arctic and Southern Oceans

    DEFF Research Database (Denmark)

    Rysgaard...[], Søren; Bendtsen, Jørgen; Delille, B.

    2011-01-01

    Although salt rejection from sea ice is a key process in deep-water formation in ice-covered seas, the concurrent rejection of CO(2) and the subsequent effect on air-sea CO(2) exchange have received little attention. We review the mechanisms by which sea ice directly and indirectly controls the air......-sea CO(2) exchange and use recent measurements of inorganic carbon compounds in bulk sea ice to estimate that oceanic CO(2) uptake during the seasonal cycle of sea-ice growth and decay in ice-covered oceanic regions equals almost half of the net atmospheric CO(2) uptake in ice-free polar seas. This sea......-ice driven CO(2) uptake has not been considered so far in estimates of global oceanic CO(2) uptake. Net CO(2) uptake in sea-ice-covered oceans can be driven by; (1) rejection during sea-ice formation and sinking of CO(2)-rich brine into intermediate and abyssal oceanic water masses, (2) blocking of air...

  14. A no-key-exchange secure image sharing scheme based on Shamir's three-pass cryptography protocol and the multiple-parameter fractional Fourier transform.

    Science.gov (United States)

    Lang, Jun

    2012-01-30

    In this paper, we propose a novel secure image sharing scheme based on Shamir's three-pass protocol and the multiple-parameter fractional Fourier transform (MPFRFT), which can safely exchange information with no advance distribution of either secret keys or public keys between users. The image is encrypted directly by the MPFRFT spectrum without the use of phase keys, and information can be shared by transmitting the encrypted image (or message) three times between users. Numerical simulation results are given to verify the performance of the proposed algorithm.

  15. Contribution of geometric design parameters to knee implant performance: Conflicting impact of conformity on kinematics and contact mechanics.

    Science.gov (United States)

    Ardestani, Marzieh M; Moazen, Mehran; Jin, Zhongmin

    2015-06-01

    Articular geometry of knee implant has a competing impact on kinematics and contact mechanics of total knee arthroplasty (TKA) such that geometry with lower contact pressure will impose more constraints on knee kinematics. The geometric parameters that may cause this competing effect have not been well understood. This study aimed to quantify the underlying relationships between implant geometry as input and its performance metrics as output. Parametric dimensions of a fixed-bearing cruciate retaining implant were randomized to generate a number of perturbed implant geometries. Performance metrics (i.e., maximum contact pressure, anterior-posterior range of motion [A-P ROM] and internal-external range of motion [I-E ROM]) of each randomized design were calculated using finite element analysis. The relative contributions of individual geometric variables to the performance metrics were then determined in terms of sensitivity indices (SI). The femoral and tibial distal or posterior radii and femoral frontal radius are the key parameters. In the sagittal plane, distal curvature of the femoral and tibial influenced both contact pressure, i.e., SI=0.57; SI=0.65, and A-P ROM, i.e., SI=0.58; SI=0.6, respectively. However, posterior curvature of the femoral and tibial implants had a smaller impact on the contact pressure, i.e., SI=0.31; SI=0.23 and a higher impact on the I-E ROM, i.e., SI=0.72; SI=0.58. It is noteworthy that in the frontal plane, frontal radius of the femoral implant impacted both contact pressure (SI=0.38) and I-E ROM (SI=0.35). Findings of this study highlighted how changes in the conformity of the femoral and tibial can impact the performance metrics. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. A Cross-Cultural Perspective of Teachers' Perceptions: What Contributions Are Exchanged between Cooperating Teachers and Student Teachers?

    Science.gov (United States)

    Clinard, Linda M.; Miron, Louis; Ariav, Tamar; Botzer, Iris; Conroy, Judy; Laycock, Kathy; Yule, Kathy

    The University of California Irvine (UCI) and Beit Berl College (BBC) in Israel developed an action research project with cooperating teachers at their Professional Development Schools. This paper examines perceptions of UCI and BBC cooperating teachers within each culture and across cultures regarding: (1) contributions teachers provide to…

  17. Surface expression of Mediterranean Water dipoles and their contribution to the shelf/slope – open ocean exchange

    Directory of Open Access Journals (Sweden)

    N. Serra

    2010-02-01

    Full Text Available The generation of dipolar eddies within the Mediterranean Water (MW layers, at the Portuguese continental slope, was observed using subsurface RAFOS floats. The surface expression of these mid-depth dipoles is here characterized with remote sensing data, namely with sea surface temperature, chlorophyll concentration and sea surface height measurements. Two cases are presented demonstrating the remote detection of these underwater structures in the Gulf of Cadiz during 1998 and 2001. The presence of subsurface MW dipoles in the Iberian coastal zone is shown to influence the development of coastal upwelling filaments. The surface circulation induced by the dipoles causes the upwelling filaments to extend offshorewards and thus to enhance the transport of physical, chemical and biological properties into the open ocean. A numerical model simulation of the ocean circulation around the Iberian Peninsula forced by heat and freshwater fluxes (computed using the NCEP reanalysis atmospheric state and by the overflow of MW at the Strait of Gibraltar, corroborates the connection between the surface and the mid-depth flows. The high-resolution numerical experiment is used to help clarifying the occurrence of the MW dipoles surface expression and the impact of these dipoles on the eddy kinetic energy of the upper ocean and on the exchange of volume and salt between the shelf/slope and the open ocean.

  18. Structure of the thoracic spiracular valves and their contribution to unidirectional gas exchange in flying blowflies Calliphora vicina.

    Science.gov (United States)

    Wasserthal, Lutz T; Fröhlich, Anja S

    2017-01-15

    The operation of the thoracic spiracular valves was analysed using anatomical and physiological techniques. Dense spiracular filter trichomes impede a diffusive gas exchange. However, the hinged posterior filter flap of the metathoracic spiracle (Sp2) opens passively during upstroke of the wings and closes by the suction of the sub-atmospheric tracheal pressure during the downstroke, which supports a unidirectional respiratory airflow. The action of the interior spiracular valve lids was recorded by photocell sensors oriented above the enlarged spiracles and projected onto the screen of a video camera. The thoracic spiracles opened much quicker (approximately 0.1 s) than they closed (1 s), suggesting that the spiracular muscles are openers, as confirmed by experimental induction of muscle contraction. Simultaneous photocell measurement revealed that the first and second thoracic spiracles act concordantly. At rest, the spiracles were mostly closed or only slightly open (flights, the valves opened wide at the start of the flight for a short time, and in many cases opened again after the flight ended. Often, the opening was wider after the flight ended than during the flight itself. During long spontaneous continuous flight phases (up to 2 h), the valves were only slightly open (flight. The advantage of generating sub-atmospheric pressure, supporting a unidirectional airflow with a PO2  increase above the resting level, is discussed. © 2017. Published by The Company of Biologists Ltd.

  19. Designing a knowledge transfer and exchange strategy for the Alberta Depression Initiative: contributions of qualitative research with key stakeholders

    Directory of Open Access Journals (Sweden)

    Mitton Craig

    2009-06-01

    Full Text Available Abstract Background Depressive disorders are highly prevalent and of significant societal burden. In fall 2004, the 'Alberta Depression Initiative' (ADI research program was formed with a mission to enhance the mental health of the Alberta population. A key expectation of the ADI is that research findings will be effectively translated to appropriate research users. To help ensure this, one of the initiatives funded through the ADI focused specifically on knowledge transfer and exchange (KTE. The objectives of this project were first to examine the state of the KTE literature, and then based on this review and a set of key informant interviews, design a KTE strategy for the ADI. Methods Face to face interviews were conducted with 15 key informants familiar with KTE and/or mental health policy and programs in Alberta. Interviews were transcribed and analyzed using the constant comparison method. Results This paper reports on findings from the qualitative interviews. Respondents were familiar with the barriers to and facilitators of KTE as identified in the existing literature. Four key themes related to the nature of effective KTE were identified in the data analysis: personal relationships, cultivating champions, supporting communities of practice, and building receptor capacity. These recommendations informed the design of a contextually appropriate KTE strategy for the ADI. The three-phased strategy involves preliminary research, public workshops, on-going networking and linkage activities and rigorous evaluation against pre-defined and mutually agreed outcome measures. Conclusion Interest in KTE on the part of ADI has led to the development of a strategy for engaging decision makers, researchers, and other mental health stakeholders in an on-going network related to depression programs and policy. A similarly engaged process might benefit other policy areas.

  20. Contribution of social isolation, restraint, and hindlimb unloading to changes in hemodynamic parameters and motion activity in rats.

    Directory of Open Access Journals (Sweden)

    Darya Tsvirkun

    Full Text Available The most accepted animal model for simulation of the physiological and morphological consequences of microgravity on the cardiovascular system is one of head-down hindlimb unloading. Experimental conditions surrounding this model include not only head-down tilting of rats, but also social and restraint stresses that have their own influences on cardiovascular system function. Here, we studied levels of spontaneous locomotor activity, blood pressure, and heart rate during 14 days under the following experimental conditions: cage control, social isolation in standard rat housing, social isolation in special cages for hindlimb unloading, horizontal attachment (restraint, and head-down hindlimb unloading. General activity and hemodynamic parameters were continuously monitored in conscious rats by telemetry. Heart rate and blood pressure were both evaluated during treadmill running to reveal cardiovascular deconditioning development as a result of unloading. The main findings of our work are that: social isolation and restraint induced persistent physical inactivity, while unloading in rats resulted in initial inactivity followed by normalization and increased locomotion after one week. Moreover, 14 days of hindlimb unloading showed significant elevation of blood pressure and slight elevation of heart rate. Hemodynamic changes in isolated and restrained rats largely reproduced the trends observed during unloading. Finally, we detected no augmentation of tachycardia during moderate exercise in rats after 14 days of unloading. Thus, we concluded that both social isolation and restraint, as an integral part of the model conditions, contribute essentially to cardiovascular reactions during head-down hindlimb unloading, compared to the little changes in the hydrostatic gradient.

  1. A high-throughput 2D-analytical technique to obtain single protein parameters from complex cell lysates for in silico process development of ion exchange chromatography.

    Science.gov (United States)

    Kröner, Frieder; Elsäßer, Dennis; Hubbuch, Jürgen

    2013-11-29

    The accelerating growth of the market for biopharmaceutical proteins, the market entry of biosimilars and the growing interest in new, more complex molecules constantly pose new challenges for bioseparation process development. In the presented work we demonstrate the application of a multidimensional, analytical separation approach to obtain the relevant physicochemical parameters of single proteins in a complex mixture for in silico chromatographic process development. A complete cell lysate containing a low titre target protein was first fractionated by multiple linear salt gradient anion exchange chromatography (AEC) with varying gradient length. The collected fractions were subsequently analysed by high-throughput capillary gel electrophoresis (HT-CGE) after being desalted and concentrated. From the obtained data of the 2D-separation the retention-volumes and the concentration of the single proteins were determined. The retention-volumes of the single proteins were used to calculate the related steric-mass action model parameters. In a final evaluation experiment the received parameters were successfully applied to predict the retention behaviour of the single proteins in salt gradient AEC. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Relative contribution of combined kinetic and exchange energy terms vs the electronic component of molecular electrostatic potential in hardness potential derivatives.

    Science.gov (United States)

    Bhattacharjee, Rituparna; Roy, Ram Kinkar

    2013-11-14

    The relative contribution of the sum of kinetic [(10/9)CFρ(r)2/3] and exchange energy [(4/9)CXρ(r)1/3] terms to that of the electronic part of the molecular electrostatic potential [Vel(r)] in the variants of hardness potential is investigated to assess the proposed definition of Δ+h(k) = −[VelN+1(k) – VelN(k)] and Δ–h(k) = −[VelN(k) – VelN–1(k)] (Saha; et al. J. Comput. Chem. 2013, 34, 662). Some substituted benzenes and polycyclic aromatic hydrocarbons (PAHs) (undergoing electrophilic aromatic substitution), carboxylic acids, and their derivatives are chosen to carry out the theoretical investigation as stated above. Intra- and intermolecular reactivity trends generated by Δ+h(k) and Δ–h(k) are found to be satisfactory and are correlated reasonably well with experimental results.

  3. Guan-Xi, Loyalty, Contribution and ‘Speak-Up Behavior: The Role of Leader-Member Exchange (LMX as Mediator and Political Skill as Moderator

    Directory of Open Access Journals (Sweden)

    Chin-Yi Shu

    2015-07-01

    Full Text Available This study investigates factors that encourage employee’s speaking-up behavior in the organization which is considered to be a risky behavior. Drawing on the principles of Uncertainty Management Theory (UMT, this research proposes that factors which embodies two key facets of certainty, confidence and control, encourages employees to speak-up to direct supervisors. This study proposes that leader-member exchange (LMX has a mediating effect on the relationship between Cheng’s categorization criteria (guan-xi, loyalty, contribution and speak-up behavior while political skill moderates the relationship between LMX and speak-up behavior. Data collected from 288 subordinates and 92 of their immediate supervisors support all hypotheses. This study reveals the effects of LMX and political skill, on ‘speak-up’ behavior and provides practical suggestions to aid employees and organizations maximize the potential of their workforce.

  4. Within-canopy and ozone fumigation effects on delta13C and Delta18O in adult beech (Fagus sylvatica) trees: relation to meteorological and gas exchange parameters.

    Science.gov (United States)

    Gessler, Arthur; Löw, Markus; Heerdt, Christian; de Beeck, Maarten Op; Schumacher, Johannes; Grams, Thorsten E E; Bahnweg, Günther; Ceulemans, Reinhart; Werner, Herbert; Matyssek, Rainer; Rennenberg, Heinz; Haberer, Kristine

    2009-11-01

    In this study, the effects of different light intensities either in direct sunlight or in the shade crown of adult beech (Fagus sylvatica L.) trees on delta13C and Delta18O were determined under ambient (1 x O3) and twice-ambient (2 x O3) atmospheric ozone concentrations during two consecutive years (2003 and 2004). We analysed the isotopic composition in leaf bulk, leaf cellulose, phloem and xylem material and related the results to (a) meteorological data (air temperature, T and relative humidity, RH), (b) leaf gas exchange measurements (stomatal conductance, g(s); transpiration rate, E; and maximum photosynthetic activity, A(max)) and (c) the outcome of a steady-state evaporative enrichment model. Delta13C was significantly lower in the shade than in the sun crown in all plant materials, whilst Delta18O was increased significantly in the shade than in the sun crown in bulk material and cellulose. Elevated ozone had no effect on delta13C, although Delta18O was influenced by ozone to varied degrees during single months. We observed significant seasonal changes for both parameters, especially in 2004, and also significant differences between the study years. Relating the findings to meteorological data and gas exchange parameters, we conclude that the differences in Delta18O between the sun and the shade crown were predominantly caused by the Péclet effect. This assumption was supported by the modelled Delta18O values for leaf cellulose. It was demonstrated that independent of RH, light-dependent reduction of stomatal conductance (and thus transpiration) and of A(max) can drive the pattern of Delta18O increase with the concomitant decrease of delta13C in the shade crown. The effect of doubling ozone levels on time-integrated stomatal conductance and transpiration as indicated by the combined analysis of Delta18O and delta13C was much lower than the influence caused by the light exposure.

  5. Valence bond/broken symmetry analysis of the exchange coupling constant in copper(II) dimers. Ferromagnetic contribution exalted through combined ligand topology and (singlet) covalent-ionic mixing.

    Science.gov (United States)

    Onofrio, Nicolas; Mouesca, Jean-Marie

    2010-05-27

    In this paper we aim at presenting a full-VB (valence-bond) analysis of the DFT broken symmetry (BS) exchange coupling constant J(BS). We extend Kahn and Briat's "two sites-two electrons" VB original formalism (Kahn, O.; Briat, B. J. Chem. Soc. Farady Trans. II, 1976, 72, 268) by taking into account the covalent-ionic singlet state mixing, here translated into intersite magnetic orbital delocalization. In this way, two explicit contributions to the magnetic orbital overlap appear, one from the purely covalent state, and the other one from the covalent-ionic mixing. This scheme allows us to relax the strict orthogonality constraint of Kahn and Briat's chemically heuristic model resulting into ferromagnetism. Moreover, we show how DFT-BS calculations applied to various copper(II) dimers yield effective parameters that can be injected into the full-VB model, allowing for a breaking down of J(BS) into various contributions, one of which being either ferromagnetic or antiferromagnetic depending on the bridging ligand topology. Two classes of systems emerge from this analysis and the exceptional ferromagnetic coupling property of the "end-on" azido-bridged copper dimer is especially emphasized.

  6. Ventilatory changes during the use of heat and moisture exchangers in patients submitted to mechanical ventilation with support pressure and adjustments in ventilation parameters to compensate for these possible changes: a self-controlled intervention study in humans.

    Science.gov (United States)

    Lucato, Jeanette Janaina Jaber; Cunha, Thiago Marraccini Nogueira da; Reis, Aline Mela Dos; Picanço, Patricia Salerno de Almeida; Barbosa, Renata Cléia Claudino; Liberali, Joyce; Righetti, Renato Fraga

    2017-01-01

    To evaluate the possible changes in tidal volume, minute volume and respiratory rate caused by the use of a heat and moisture exchanger in patients receiving pressure support mechanical ventilation and to quantify the variation in pressure support required to compensate for the effect caused by the heat and moisture exchanger. Patients under invasive mechanical ventilation in pressure support mode were evaluated using heated humidifiers and heat and moisture exchangers. If the volume found using the heat and moisture exchangers was lower than that found with the heated humidifier, an increase in pressure support was initiated during the use of the heat and moisture exchanger until a pressure support value was obtained that enabled the patient to generate a value close to the initial tidal volume obtained with the heated humidifier. The analysis was performed by means of the paired t test, and incremental values were expressed as percentages of increase required. A total of 26 patients were evaluated. The use of heat and moisture exchangers increased the respiratory rate and reduced the tidal and minute volumes compared with the use of the heated humidifier. Patients required a 38.13% increase in pressure support to maintain previous volumes when using the heat and moisture exchanger. The heat and moisture exchanger changed the tidal and minute volumes and respiratory rate parameters. Pressure support was increased to compensate for these changes.

  7. Stable oxygen isotope and flux partitioning demonstrates understory of an oak savanna contributes up to half of ecosystem carbon and water exchange

    Directory of Open Access Journals (Sweden)

    Maren eDubbert

    2014-10-01

    Full Text Available Semi-arid ecosystems contribute about 40% to global net primary production (GPP even though water is a major factor limiting carbon uptake. Evapotranspiration (ET accounts for up to 95% of the water loss and in addition, vegetation can also mitigate drought effects by altering soil water distribution. Hence, partitioning of carbon and water fluxes between the soil and vegetation components is crucial to gain mechanistic understanding of vegetation effects on carbon and water cycling. However, the possible impact of herbaceous vegetation in savanna type ecosystems is often overlooked. Therefore, we aimed at quantifying understory vegetation effects on the water balance and productivity of a Mediterranean oak savanna. ET and net ecosystem CO2 exchange (NEE were partitioned based on flux and stable oxygen isotope measurements and also rain infiltration was estimated.The understory vegetation contributed importantly to total ecosystem ET and GPP with a maximum of 43% and 51%, respectively. It reached water-use efficiencies (WUE; ratio of carbon gain by water loss similar to cork-oak trees. The understory vegetation inhibited soil evaporation (E and, although E was large during wet periods, it did not diminish WUE during water-limited times. The understory strongly increased soil water infiltration, specifically following major rain events. At the same time, the understory itself was vulnerable to drought, which led to an earlier senescence of the understory growing under trees as compared to open areas, due to competition for water. Thus, beneficial understory effects are dominant and contribute to the resilience of this ecosystem. At the same time the vulnerability of the understory to drought suggests that future climate change scenarios for the Mediterranean basin threaten understory development. This in turn will very likely diminish beneficial understory effects like infiltration and ground water recharge and therefore ecosystem resilience to

  8. Reverse mode Na+/Ca2+ exchange mediated by STIM1 contributes to Ca2+ influx in airway smooth muscle following agonist stimulation

    Directory of Open Access Journals (Sweden)

    Fox Jane

    2010-12-01

    Full Text Available Abstract Background Agonist stimulation of airway smooth muscle (ASM results in IP3 mediated Ca2+ release from the sarcoplasmic reticulum followed by the activation of store operated and receptor operated non-selective cation channels. Activation of these non-selective channels also results in a Na+ influx. This localised increase in Na+ levels can potentially switch the Na+/Ca2+ exchanger into reverse mode and so result in a further influx of Ca2+. The aim of this study was to characterise the expression and physiological function of the Na+/Ca2+ exchanger in cultured human bronchial smooth muscle cells and determine its contribution to agonist induced Ca2+ influx into these cells. Methods The expression profile of NCX (which encodes the Na+/Ca2+ exchanger homologues in cultured human bronchial smooth muscle cells was determined by reverse transcriptase PCR. The functional activity of reverse mode NCX was investigated using a combination of whole cell patch clamp, intracellular Ca2+ measurements and porcine airway contractile analyses. KB-R7943 (an antagonist for reverse mode NCX and target specific siRNA were utilised as tools to inhibit NCX function. Results NCX1 protein was detected in cultured human bronchial smooth muscle cells (HBSMC cells and NCX1.3 was the only mRNA transcript variant detected. A combination of intracellular Na+ loading and addition of extracellular Ca2+ induced an outwardly rectifying current which was augmented following stimulation with histamine. This outwardly rectifying current was inhibited by 10 μM KB-R7943 (an antagonist of reverse mode NCX1 and was reduced in cells incubated with siRNA against NCX1. Interestingly, this outwardly rectifying current was also inhibited following knockdown of STIM1, suggesting for the first time a link between store operated cation entry and NCX1 activation. In addition, 10 μM KB-R7943 inhibited agonist induced changes in cytosolic Ca2+ and induced relaxation of porcine

  9. Kinetic parameters, collision rates, energy exchanges and transport coefficients of non-thermal electrons in premixed flames at sub-breakdown electric field strengths

    KAUST Repository

    Bisetti, Fabrizio

    2014-01-02

    The effects of an electric field on the collision rates, energy exchanges and transport properties of electrons in premixed flames are investigated via solutions to the Boltzmann kinetic equation. The case of high electric field strength, which results in high-energy, non-thermal electrons, is analysed in detail at sub-breakdown conditions. The rates of inelastic collisions and the energy exchange between electrons and neutrals in the reaction zone of the flame are characterised quantitatively. The analysis includes attachment, ionisation, impact dissociation, and vibrational and electronic excitation processes. Our results suggest that Townsend breakdown occurs for E/N = 140 Td. Vibrational excitation is the dominant process up to breakdown, despite important rates of electronic excitation of CO, CO2 and N2 as well as impact dissociation of O2 being apparent from 50 Td onwards. Ohmic heating in the reaction zone is found to be negligible (less than 2% of peak heat release rate) up to breakdown field strengths for realistic electron densities equal to 1010 cm-3. The observed trends are largely independent of equivalence ratio. In the non-thermal regime, electron transport coefficients are insensitive to mixture composition and approximately constant across the flame, but are highly dependent on the electric field strength. In the thermal limit, kinetic parameters and transport coefficients vary substantially across the flame due to the spatially inhomogeneous concentration of water vapour. A practical approach for identifying the plasma regime (thermal versus non-thermal) in studies of electric field effects on flames is proposed. © 2014 Taylor & Francis.

  10. On-shell gauge-parameter independence of contributions to electroweak quark self-energies

    Energy Technology Data Exchange (ETDEWEB)

    Ahmady, M.R.; Elias, V.; Mendel, R.R.; Scadron, M.D.; Steele, T.

    1989-05-01

    We allow an external condensate to enter standard SU(2) x U(1) electroweak theory via the vacuum expectation value <0chemically bond:q-bar(x)q(y):chemically bond0>, as in QCD sum-rule applications. For a given flavor, we then find that any gauge-parameter dependence of quark self-energies on the ''mass shell'' is eliminated provided that the mass shell is made to coincide with both the expansion-parameter mass occurring in the operator-product expansion of <0chemically bond:q-bar(x)q(y):chemically bond0> and the standard electroweak mass acquired via the Yukawa coupling to the usual scalar vacuum expectation value of spontaneous symmetry breaking. This result indicates that if the QCD-generated order parameter and associated dynamical mass(es) m/sub q//sup dyn/ are utilized as external input parameters in electroweak calculations involving hadrons, then new corrections must be introduced into the q-barqW and q-barqZ vertices in order to preserve SU(2) x U(1) Ward identities.

  11. Making sense of nonsense in British Sign Language (BSL): The contribution of different phonological parameters to sign recognition

    NARCIS (Netherlands)

    Orfanidou, E.; Adam, R.; McQueen, J.M.; Morgan, G.

    2009-01-01

    Do all components of a sign contribute equally to its recognition? In the present study, misperceptions in the sign-spotting task (based on the word-spotting task; Cutler & Norris, 1988) were analyzed to address this question. Three groups of deaf signers of British Sign Language (BSL) with

  12. Inhibition of the sarcoplasmic reticulum Ca2+ pump with thapsigargin to estimate the contribution of Na+-Ca2+ exchange to ventricular myocyte relaxation

    Directory of Open Access Journals (Sweden)

    Bassani R.A.

    2003-01-01

    Full Text Available Relaxation in the mammalian ventricle is initiated by Ca2+ removal from the cytosol, which is performed by three main transport systems: sarcoplasmic reticulum Ca2+-ATPase (SR-A, Na+-Ca2+ exchanger (NCX and the so-called slow mechanisms (sarcolemmal Ca2+-ATPase and mitochondrial Ca2+ uptake. To estimate the relative contribution of each system to twitch relaxation, SR Ca2+ accumulation must be selectively inhibited, usually by the application of high caffeine concentrations. However, caffeine has been reported to often cause changes in membrane potential due to NCX-generated inward current, which compromises the reliability of its use. In the present study, we estimated integrated Ca2+ fluxes carried by SR-A, NCX and slow mechanisms during twitch relaxation, and compared the results when using caffeine application (Cf-NT and an electrically evoked twitch after inhibition of SR-A with thapsigargin (TG-TW. Ca2+ transients were measured in 20 isolated adult rat ventricular myocytes with indo-1. For transients in which one or more transporters were inhibited, Ca2+ fluxes were estimated from the measured free Ca2+ concentration and myocardial Ca2+ buffering characteristics. NCX-mediated integrated Ca2+ flux was significantly higher with TG-TW than with Cf-NT (12 vs 7 µM, whereas SR-dependent flux was lower with TG-TW (77 vs 81 µM. The relative participations of NCX (12.5 vs 8% with TG-TW and Cf-NT, respectively and SR-A (85 vs 89.5% with TG-TW and Cf-NT, respectively in total relaxation-associated Ca2+ flux were also significantly different. We thus propose TG-TW as a reliable alternative to estimate NCX contribution to twitch relaxation in this kind of analysis.

  13. New parameters available on Sysmex XE-5000 hematology analyzers contribute to differentiating dengue from leptospirosis and enteric fever.

    Science.gov (United States)

    Oehadian, A; Michels, M; de Mast, Q; Prihatni, D; Puspita, M; Hartantri, Y; Sinarta, S; van der Ven, A J A M; Alisjahbana, B

    2015-12-01

    Distinguishing dengue virus infection from other febrile thrombocytopenic illnesses such as leptospirosis or enteric fever is important but difficult, due to the unavailability of reliable diagnostic tests. Sysmex XE-5000 hematology analyzers use fluorescence flow cytometry to quantitate new parameters including cells in the atypical lymphocyte area (AL), high-fluorescent lymphocyte counts (HFLC), immature granulocytes (IG), and immature platelets (IPF). This study aimed to investigate whether these parameters can help to discriminate between the diseases. We compared hematocytometry performed by a Sysmex XE-5000 analyzer in Indonesian adults with dengue (n = 93), leptospirosis (n = 11), and enteric fever (n = 6) infection, and in healthy controls (n = 28). Receiver operating characteristic curves comparing dengue and leptospirosis showed that dengue was characterized by increased %AL (AUC 0.87; 95% CI 0.70-1.03), %HFLC (AUC 0.89; 95% CI 0.78-0.99), and %IPF (AUC 0.81; 95% CI 0.65-0.97), while patients with leptospirosis had increased %IG (AUC 0.86; 95% CI 0.71-1.02). Low %AL, %HFLC, and %IG supported a diagnosis of enteric fever. The detection of AL, HFLC, IG, and IPF by Sysmex XE-5000 hematology analyzers can help to differentiate between common causes of febrile illnesses with thrombocytopenia in dengue endemic areas. We recommend further investigating the discriminatory value of these parameters in clinical practice. © 2015 John Wiley & Sons Ltd.

  14. The influence of ions of the cadmium and the lead on some parameters of the lipid exchanges and the system of antioxidant protection of carp (Сyprinus Сarpio L.

    Directory of Open Access Journals (Sweden)

    B. S. Musaev

    2009-01-01

    Full Text Available The influence of chronic pollution of the water environment by ions of the cadmium and the lead (5, 15, 30 and 40-th days on some parameters of the lipid exchanges and the systems of antioxidant protection of tissues of the liver, kidneys, muscles and the brain of the carp (Cyprinus Сarpio L. are studied.

  15. Bepicolombo Laser Altimeter (BELA) contributions to MPO orbit improvement towards a better determination of Mercury geophysical parameters

    Science.gov (United States)

    Hosseiniarani, A.; Bertone, S.; Jäggi, A.; Thomas, N.

    2017-09-01

    Laser altimetry is the main source of information to improve planetary topography. However, it is also possible to use it in the form of crossovers to significantly improve the spacecraft orbit and infer geophysical properties. In this study we will present our latest results on modeling BELA instrument in flight and the potential improvement of MPO orbit. The impact of using altimetry crossovers on Mercury geophysical parameters is one of the final goals of this study and will be the object of future talks.

  16. A Comprehensive Methodology for Development, Parameter Estimation, and Uncertainty Analysis of Group Contribution Based Property Models -An Application to the Heat of Combustion

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Marcarie, Camille; Abildskov, Jens

    2016-01-01

    of the prediction. The methodology is evaluated through development of a GC method for the prediction of the heat of combustion (ΔHco) for pure components. The results showed that robust regression lead to best performance statistics for parameter estimation. The bootstrap method is found to be a valid alternative......A rigorous methodology is developed that addresses numerical and statistical issues when developing group contribution (GC) based property models such as regression methods, optimization algorithms, performance statistics, outlier treatment, parameter identifiability, and uncertainty...... identifiability issues, reporting of the 95% confidence intervals of the predicted property values should be mandatory as opposed to reporting only single value prediction, currently the norm in literature. Moreover, inclusion of higher order groups (additional parameters) does not always lead to improved...

  17. Assessing the Contribution of the Environmental Parameters to Eutrophication with the Use of the "PaD" and "PaD2" Methods in a Hypereutrophic Lake.

    Science.gov (United States)

    Hadjisolomou, Ekaterini; Stefanidis, Konstantinos; Papatheodorou, George; Papastergiadou, Evanthia

    2016-07-28

    Lake Pamvotis (Greece) is a shallow hypereutrophic lake with a natural tendency to eutrophication. Several restoration measures were applied, but with no long-term success. To examine the causes for this an Artificial Neural Network (ANN) was created in order to simulate the chlorophyll-a (Chl-a) levels and to investigate the role of the associated environmental parameters. The ANN managed to simulate with good correlation the simulated Chl-a and can be considered as a reliable predictor. The relative importance of the environmental parameters to the simulated Chl-a was calculated with the use of the "Partial Derivatives" ("PaD") sensitivity method. The water temperature (WT) and soluble reactive phosphorus (SRP) had the highest relative importance, with values of 50% and 17%, respectively. The synergistic effect of the paired parameters was calculated with the use of the "PaD2" algorithm. The SRP-WT paired parameter was the most influential, with a relative contribution of 22%. The ANN showed that Lake Pamvotis is prone to suffer the effects of climatic change, because of the major contribution of WT. The ANN also revealed that combined nutrients reduction would improve water quality status. The ANN findings can act as an advisory tool regarding any restoration efforts.

  18. Estimation of Total Fusion Reactivity and Contribution from Suprathermal Tail using 3-parameter Dagum Ion Speed Distribution

    CERN Document Server

    Majumdar, Rudrodip

    2016-01-01

    Thermonuclear fusion reactivity is a pivotal quantity in the studies pertaining to fusion energy production, fusion ignition and energy break-even analysis in both inertially and magnetically confined systems. Although nuclear fusion reactivity and thereafter the power density of a magnetic confinement fusion reactor and the fulfillment of the ignition criterion are quantitatively determined by assuming the ion speed distribution to be Maxwellian, a significant population of suprathermal ions,with energy greater than the quasi-Maxwellian background plasma temperature, is generated by the fusion reactions and auxiliary heating in the fusion devices. In the current work 3-parameter Dagum speed distribution has been introduced to include the effect of suprathermal ion population in the calculation of total fusion reactivity. The extent of enhancement in the fusion reactivity, at different back-ground temperatures of the fusion fuel plasma, due to the suprathermal ion population has also been discussed.

  19. Contribution of counterions and degree of ionization for birefringence creation and relaxation kinetics parameters of PAH/PAZO films

    Energy Technology Data Exchange (ETDEWEB)

    Raposo, Maria, E-mail: mfr@fct.unl.pt; Monteiro Timóteo, Ana Rita; Ribeiro, Paulo A. [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, UNL, Campus de Caparica, 2829-516 Caparica (Portugal); Ferreira, Quirina [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, UNL, Campus de Caparica, 2829-516 Caparica (Portugal); Instituto de Telecomunicações, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, P-1049-001 Lisboa (Portugal); Botelho do Rego, Ana Maria [Centro de Química-Física Molecular and IN, Complexo Interdisciplinar, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisboa (Portugal)

    2015-09-21

    Photo induced birefringent materials can be used to develop optical and conversion energy devices, and consequently, the study of the variables that influences the creation and relaxation of birefringence should be carefully analyzed. In this work, the parameters of birefringence creation and relaxation kinetics curves obtained on layer-by-layer (LBL) films, prepared from azo-polyectrolyte poly[1-[4-(3-carboxy-4 hydroxyphenylazo) benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) and poly(allylamine hydrochloride)(PAH), are related with the presence of counterions and the degree of ionization of the polyelectrolytes. Those kinetics curves obtained on PAH/PAZO LBL films, prepared from PAH solutions with different pHs and maintaining the pH of PAZO solution constant at pH = 9, were analyzed taking into account the films composition which was characterized by X-ray photoelectron spectroscopy. The creation and relaxation birefringence curves are justified by two processes: one associated to local mobility of the azobenzene with a characteristic time 30 s and intensity constant and other associated with polymeric chains mobility with the characteristic time and intensity decreasing with pH. These results allow us to conclude that the birefringence creation process, associated to local mobility of azobenzenes is independent of the degree of ionization and of number of counterions or co-ions present while the birefringence creation process associated to mobility of chains have its characteristic time and intensity dependent of both degree of ionization and number of counterions. The birefringence relaxation processes are dependent of the degree of ionization. The analysis of the films composition revealed, in addition, the presence of a protonated secondary or tertiary amine revealing that PAZO may have positive charges and consequently a zwitterionic behavior.

  20. Assessment of organic compound exposures, thermal comfort parameters, and HVAC system-driven air exchange rates in public school portable classrooms in California

    Energy Technology Data Exchange (ETDEWEB)

    Shendell, Derek Garth [Univ. of California, Los Angeles, CA (United States)

    2003-01-01

    The prevalence of prefabricated, portable classrooms (portables, relocatables, RCs) has increased due to class size reduction initiatives and limited resources. Classroom mechanical wall-mount heating, ventilation, and air conditioning (HVAC) systems may function improperly or not be maintained; lower ventilation rates may impact indoor air and environmental quality (IEQ). Materials in portables may off-gas volatile organic compounds (VOCs), including formaldehyde, as a function of age, temperature, and humidity. For a pilot study, public K-12 schools located in or serving target areas within five Los Angeles County communities were identified. In two communities where school districts (SD) consented, 1-3 randomly selected portables, one newer and one older, and one main building control classroom from each participating school were included. Sampling was conducted over a five-day school week in the cooling and heating seasons, or repeated twice in the cooling season. Measurements included passive samplers for VOCs, formaldehyde and acetaldehyde, and air exchange rate (AER) calculation; indoor air temperature and humidity; technician walk-through surveys; an interview questionnaire above HVAC system operation and maintenance (O and M). For an intervention study evaluating advanced HVAC technologies in comparison to the common conventional technology, and materials for source reduction of VOCs, four RC were manufactured and located in pairs at two schools in two recruited Northern California SD in different climate zones. RCs were built with the two HVAC systems, cabinetry and conduit for monitoring equipment, and standard or advanced interior finish materials. Each RC was its own control in a case-crossover design--HVAC systems alternately operated for 1-2 week intervals in the 2001-02 school year, with IEQ monitoring including aldehyde and indoor air temperature and humidity data. Measured classroom AER were low, formaldehyde concentrations were below the state

  1. Contributions of structural connectivity and cerebrovascular parameters to functional magnetic resonance imaging signals in mice at rest and during sensory paw stimulation.

    Science.gov (United States)

    Schroeter, Aileen; Grandjean, Joanes; Schlegel, Felix; Saab, Bechara J; Rudin, Markus

    2017-07-01

    Previously, we reported widespread bilateral increases in stimulus-evoked functional magnetic resonance imaging signals in mouse brain to unilateral sensory paw stimulation. We attributed the pattern to arousal-related cardiovascular changes overruling cerebral autoregulation thereby masking specific signal changes elicited by local neuronal activity. To rule out the possibility that interhemispheric neuronal communication might contribute to bilateral functional magnetic resonance imaging responses, we compared stimulus-evoked functional magnetic resonance imaging responses to unilateral hindpaw stimulation in acallosal I/LnJ, C57BL/6, and BALB/c mice. We found bilateral blood-oxygenation-level dependent signal changes in all three strains, ruling out a dominant contribution of transcallosal communication as reason for bilaterality. Analysis of functional connectivity derived from resting-state functional magnetic resonance imaging, revealed that bilateral cortical functional connectivity is largely abolished in I/LnJ animals. Cortical functional connectivity in all strains correlated with structural connectivity in corpus callosum as revealed by diffusion tensor imaging. Given the profound influence of systemic hemodynamics on stimulus-evoked functional magnetic resonance imaging outcomes, we evaluated whether functional connectivity data might be affected by cerebrovascular parameters, i.e. baseline cerebral blood volume, vascular reactivity, and reserve. We found that effects of cerebral hemodynamics on functional connectivity are largely outweighed by dominating contributions of structural connectivity. In contrast, contributions of transcallosal interhemispheric communication to the occurrence of ipsilateral functional magnetic resonance imaging response of equal amplitude to unilateral stimuli seem negligible.

  2. Relative contributions of Na+/H+ exchange and Na+/HCO3- cotransport to ischemic Na-i(+) overload in isolated rat hearts

    NARCIS (Netherlands)

    Ten Hove, M; Nederhoff, MGJ; Van Echteld, CJA

    The Na+/H+ exchanger (NHE) and/or the Na+/HCO3- cotransporter (NBC) were blocked during ischemia in isolated rat hearts. Intracellular Na+ concentration ([Na+](i)), intracellular pH (pH(i)), and energy-related phosphates were measured by using simultaneous Na-23 and P-31 NMR spectroscopy. Hearts

  3. Calculations of the dominant long-range, spin-independent contributions to the interaction energy between two nonrelativistic Dirac fermions from double-boson exchange of spin-0 and spin-1 bosons with spin-dependent couplings

    Science.gov (United States)

    Aldaihan, S.; Krause, D. E.; Long, J. C.; Snow, W. M.

    2017-05-01

    Various theories beyond the Standard Model predict new particles with masses in the sub-eV range with very weak couplings to ordinary matter which can possess spin-dependent couplings to electrons and nucleons. Present laboratory constraints on exotic spin-dependent interactions with pseudoscalar and axial couplings for exchange boson masses between meV and eV are very poor compared to constraints on spin-independent interactions in the same mass range arising from spin-0 and spin-1 boson exchange. It is therefore interesting to analyze in a general way how one can use the strong experimental bounds on spin-independent interactions to also constrain spin-dependent interactions by considering higher-order exchange processes. The exchange of a pair of bosons between two fermions with spin-dependent couplings will possess contributions which flip spins twice and thereby generate a polarization-independent interaction energy which can add coherently between two unpolarized objects. In this paper we derive the dominant long-range contributions to the interaction energy between two nonrelativistic spin-1 /2 Dirac fermions from double exchange of spin-0 and spin-1 bosons proportional to couplings of the form gP4, gS2gP2, and gV2gA2 . Our results for gP4 are in agreement with previous calculations that have appeared in the literature. We demonstrate the usefulness of this analysis to constrain spin-dependent couplings by presenting the results of a reanalysis of data from a short-range gravity experiment to derive an improved constraint on (gPN)2, the pseudoscalar coupling for nucleons, in the range between 40 and 200 μ m of about a factor of 5 compared to previous limits. We hope that the expressions derived in this work will be employed by other researchers in the future to evaluate whether or not they can constrain exotic spin-dependent interactions from spin-independent measurements. The spin-independent contribution from 2-boson exchange with axial vector couplings

  4. Interface exchange parameters in La{sub 2/3}Ca{sub 1/3}Mn{sub 3}O/La{sub 1/3}Ca{sub 2/3}Mn{sub 3}O bilayers: a Monte Carlo approach

    Energy Technology Data Exchange (ETDEWEB)

    Restrepo-Parra, E., E-mail: erestrepopa@unal.edu.co [Universidad Nacional de Colombia-Sede Manizales, PCM Computational Applications, Manizales (Colombia); Londoño-Navarro, J. [Universidad Nacional de Colombia-Sede Manizales, PCM Computational Applications, Manizales (Colombia); Restrepo, J. [Grupo de Magnetismo y Simulación. Instituto de Física. Universidad de Antioquia. A.A. 1226, Medellín (Colombia)

    2013-10-15

    Ferromagnetic/antiferromagnetic (FM/AF) bilayers have been widely studied because they exhibit special phenomena, such as exchange bias and magnetoresistance. These effects are strongly influenced by interface behavior. In this work, a study of hysteresis loops in La{sub 2/3}Ca{sub 1/3}MnO{sub 3}/La{sub 1/3}Ca{sub 2/3}MnO{sub 3} bilayers is presented. Simulations were carried out using the Monte Carlo method combined with the Metropolis algorithm and Heisenberg model. The study was focused on determining the most suitable exchange parameters at the interface by applying the model proposed by Kiwi. This model considers the use of two interface exchange parameters to represent the anisotropy that occurs at the interface because of the contact between two phases (ferromagnetic and antiferromagnetic). These two interface exchange parameters were named J{sub I1} and J{sub I2}. Initially, we assumed J{sub I1} to be equal to J{sub I2} without presenting exchange bias. Then, J{sub I1} and J{sub I2} were assumed to be different. In this configuration, the exchange phenomenon appeared in the hysteresis loops. It was also observed that the exchange bias is strongly dependent on the ratio of J{sub I1} to J{sub I2}. As J{sub I1} increases, the exchange bias decreases slowly and becomes comparable to the effective exchange bias field, assuming that it only depends on ΔJ{sub I}=J{sub I1}−J{sub I2}. - Highlights: • Exchange bias is influenced by the type of interaction ions and exchange parameters. • An interface asymmetric is required for observing the exchange bias phenomenon. • Monte Carlo method allows simulating the exchange bias phenomenon in FM/AF systems.

  5. arXiv Complete two-loop QCD contributions to the lightest Higgs-boson mass in the MSSM with complex parameters

    CERN Document Server

    Borowka, Sophia; Weiglein, Georg

    Higher-order corrections to the Higgs-boson masses within the MSSM are desirable for accurate predictions currently testable at the LHC. From the comparison of the prediction with the measured value of the mass of the discovered Higgs signal, constraints on the available parameter space can be inferred. In order to improve on the accuracy of current predictions, all two-loop corrections involving the strong coupling are computed for the Higgs-boson mass spectrum of the MSSM with complex parameters. Apart from the dependence on the strong coupling, these contributions depend on the weak coupling, leading to terms of $\\mathcal{O}{\\left(\\alpha\\alpha_s\\right)}$, or on Yukawa couplings, leading to terms of $\\mathcal{O}{\\left(\\sqrt{\\alpha_{q_1}}\\sqrt{\\alpha_{q_2}}\\alpha_s\\right)}$, ($q_{1,2}=t,b,c,s,u,d$; flavor-violation effects are neglected). The full dependence on the external momentum at the two-loop level and on all relevant mass scales is taken into account. The calculation is performed in the Feynman-diagra...

  6. Barter exchanges

    DEFF Research Database (Denmark)

    Sudzina, Frantisek

    Although barter is often perceived as something that proceeded money, barter is still used. The focus of the paper is on barter exchanges. Barter exchanges are used both in developing countries as well as in developed countries (including the U.S.). They are used by both organizations...... and individuals. They usually allow to exchange good but some include also services. Some exchanges allow only for bi-directional barter, i.e. when only two parties are involved in the exchange. But probably most of the barter exchanges use barter money; this makes it easier to exchange goods and services...

  7. O3 and NOx Exchange

    NARCIS (Netherlands)

    Loubet, B.; Castell, J.F.; Laville, P.; Personne, E.; Tuzet, A.; Ammann, C.; Emberson, L.; Ganzeveld, L.; Kowalski, A.S.; Merbold, L.; Stella, P.; Tuovinen, J.P.

    2015-01-01

    This discussion was based on the background document “Review on modelling atmosphere-biosphere exchange of Ozone and Nitrogen oxides”, which reviews the processes contributing to biosphere-atmosphere exchange of O3 and NOx, including stomatal and non-stomatal exchange of O3 and NO, NO2.

  8. A new approach to the joined estimation of the heat generated by a semicontiunuous emulsion polymerization Qr and the overall heat exchange parameter UA

    Directory of Open Access Journals (Sweden)

    Freire F. B.

    2004-01-01

    Full Text Available This work is concerned with the coupled estimation of the heat generated by the reaction (Qr and the overall heat transfer parameter (UA during the terpolymerization of styrene, butyl acrylate and methyl methacrylate from temperature measurements and the reactor heat balance. By making specific assumptions about the dynamics of the evolution of UA and Q R, we propose a cascade of observers to successively estimate these two parameters without the need for additional measurements of on-line samples. One further aspect of our approach is that only the energy balance around the reactor was employed. It means that the flow rate of the cooling jacket fluid was not required.

  9. Cryptographic Combinatorial Securities Exchanges

    Science.gov (United States)

    Thorpe, Christopher; Parkes, David C.

    We present a useful new mechanism that facilitates the atomic exchange of many large baskets of securities in a combinatorial exchange. Cryptography prevents information about the securities in the baskets from being exploited, enhancing trust. Our exchange offers institutions who wish to trade large positions a new alternative to existing methods of block trading: they can reduce transaction costs by taking advantage of other institutions’ available liquidity, while third party liquidity providers guarantee execution—preserving their desired portfolio composition at all times. In our exchange, institutions submit encrypted orders which are crossed, leaving a “remainder”. The exchange proves facts about the portfolio risk of this remainder to third party liquidity providers without revealing the securities in the remainder, the knowledge of which could also be exploited. The third parties learn either (depending on the setting) the portfolio risk parameters of the remainder itself, or how their own portfolio risk would change if they were to incorporate the remainder into a portfolio they submit. In one setting, these third parties submit bids on the commission, and the winner supplies necessary liquidity for the entire exchange to clear. This guaranteed clearing, coupled with external price discovery from the primary markets for the securities, sidesteps difficult combinatorial optimization problems. This latter method of proving how taking on the remainder would change risk parameters of one’s own portfolio, without revealing the remainder’s contents or its own risk parameters, is a useful protocol of independent interest.

  10. The fluvial geochemistry, contributions of silicate, carbonate and saline-alkaline components to chemical weathering flux and controlling parameters: Narmada River (Deccan Traps), India

    Science.gov (United States)

    Gupta, Harish; Chakrapani, Govind J.; Selvaraj, Kandasamy; Kao, Shuh-Ji

    2011-02-01

    The Narmada River in India is the largest west-flowing river into the Arabian Sea, draining through the Deccan Traps, one of the largest flood basalt provinces in the world. The fluvial geochemical characteristics and chemical weathering rates (CWR) for the mainstream and its major tributaries were determined using a composite dataset, which includes four phases of seasonal field (spot) samples (during 2003 and 2004) and a decade-long (1990-2000) fortnight time series (multiannual) data. Here, we demonstrate the influence of minor lithologies (carbonates and saline-alkaline soils) on basaltic signature, as reflected in sudden increases of Ca 2+-Mg 2+ and Na + contents at many locations along the mainstream and in tributaries. Both spot and multiannual data corrected for non-geological contributions were used to calculate the CWR. The CWR for spot samples (CWR spot) vary between 25 and 63 ton km -2 year -1, showing a reasonable correspondence with the CWR estimated for multiannual data (CWR multi) at most study locations. The weathering rates of silicate ( SilWR), carbonate ( CarbWR) and evaporite ( Sal-AlkWR) have contributed ˜38-58, 28-45 and 8-23%, respectively to the CWR spot at different locations. The estimated SilWR (11-36 ton km -2 year -1) for the Narmada basin indicates that the previous studies on the North Deccan Rivers (Narmada-Tapti-Godavari) overestimated the silicate weathering rates and associated CO 2 consumption rates. The average annual CO 2 drawdown via silicate weathering calculated for the Narmada basin is ˜0.032 × 10 12 moles year -1, suggesting that chemical weathering of the entire Deccan Trap basalts consumes approximately 2% (˜0.24 × 10 12 moles) of the annual global CO 2 drawdown. The present study also evaluates the influence of meteorological parameters (runoff and temperature) and physical weathering rates (PWR) in controlling the CWR at annual scale across the basin. The CWR and the SilWR show significant correlation with runoff

  11. Optimization of Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Ivan Catton

    2010-10-01

    The objective of this research is to develop tools to design and optimize heat exchangers (HE) and compact heat exchangers (CHE) for intermediate loop heat transport systems found in the very high temperature reator (VHTR) and other Generation IV designs by addressing heat transfer surface augmentation and conjugate modeling. To optimize heat exchanger, a fast running model must be created that will allow for multiple designs to be compared quickly. To model a heat exchanger, volume averaging theory, VAT, is used. VAT allows for the conservation of mass, momentum and energy to be solved for point by point in a 3 dimensional computer model of a heat exchanger. The end product of this project is a computer code that can predict an optimal configuration for a heat exchanger given only a few constraints (input fluids, size, cost, etc.). As VAT computer code can be used to model characteristics )pumping power, temperatures, and cost) of heat exchangers more quickly than traditional CFD or experiment, optimization of every geometric parameter simultaneously can be made. Using design of experiment, DOE and genetric algorithms, GE, to optimize the results of the computer code will improve heat exchanger disign.

  12. Sister chromatid exchange and micronucleus frequency in human lymphocytes of 1,650 subjects in an Italian population: I. Contribution of methodological factors.

    Science.gov (United States)

    Barale, R; Marrazzini, A; Bacci, E; Di Sibio, A; Tessa, A; Cocchi, L; Scarcelli, V; Lubrano, V; Vassalle, C; Landi, S

    1998-01-01

    The influence of several methodological factors on mean values of sister chromatid exchanges (SCEs) and micronuclei (MN) in peripheral lymphocytes of 1,650 subjects was analyzed. Donors belonged to a general healthy population living in Pisa and in two nearby small cities: Cascina and Navacchio (Ca-Na). Blood samples were collected over a period of 29 months and processed in three different laboratories of the some institute. Slides were analyzed by several scorers. Our data showed that lymphocyte proliferation indexes (PIs) and baseline mean values of SCEs were affected mainly by sampling period. This factor accounted for a percentage ranging from roughly 10% (Pisa) to 20% (Ca-Na) of total SCE variance and from roughly 10% (Pisa) to 13% (Ca-Na) of total PIs variance. A marginal effect was attributable to the different laboratories involved (maximum 3% for SCEs and 7% for PIs). The sampling period variable included many sources of variability such as culture media batches, fetal calf serum, PHA, BrdUrd, and seasonality. MN counts revealed a more marked dependence on processing laboratories. This factor accounted for a percentage of roughly 10% (Pisa and Ca-Na) of total variance, while the sampling period was marginally effective (about 1-4% of total variability). Because laboratories were equipped and supplied with the same materials and consumables and technicians were rotated constantly, the only variable ascertained was represented by the three different models of CO2 incubators used for lymphocyte culturing. When "month" and "incubator" variables were considered jointly, experimental variability accounted for 15-20% of total variance, both for PIs and mean values SCEs and MN. The variability due to slide scoring was reduced by assigning each slide to five different scorers and matching low with high scorers in each group. Present data show that when the study is performed under these controlled conditions, about 20% of total interdonor variability can be

  13. Critical power concept adapted for the specific table tennis test: comparisons between exhaustion criteria, mathematical modeling, and correlation with gas exchange parameters.

    Science.gov (United States)

    Zagatto, A; Miranda, M F; Gobatto, C A

    2011-07-01

    The purposes of this study were to determine and to compare the critical power concept adapted for the specific table tennis test (critical frequency - C F ) estimated from 5 mathematical models and using 2 different exhaustion criteria (voluntary and technical exhaustions). Also, it was an aim to assess the relationship between C F estimated from mathematical models and respiratory compensation point (RCP), peak oxygen uptake ( V˙O (2PEAK)) and minimal intensity at which V˙O (2PEAK) ( F V˙O (2PEAK)) appears. 9 male table tennis players [18(1) years; 62.3(4.4) kg] performed the maximal incremental test and 3-4 exhaustive exercise bouts to estimate C F s (balls · min (-1)). The exhaustion time and C F obtained were independent of the exhaustion criteria. The C F from 3-parameter model [45.2(7.0)-voluntary, 43.2(5.6)-technical] was lower than C F estimated by linear 2-parameter models, frequency-time (-1) [53.5(3.6)-voluntary, 53.5(3.5)-technical] and total ball thrown-time [52.2(3.5)-voluntary, 52.2(3.5)-technical] but significantly correlated. C F values from 2 linear models were significantly correlated with RCP [47.4(3.4) balls · min (-1)], and C F values of the linear and nonlinear models were correlated with F V˙O (2PEAK) [56.7(3.4) balls · min (-1)]. However, there were no significant correlations between C F values and V˙O (2PEAK) [49.8(1.1)ml · kg (-1) · min (-1)]. The results were not modified by exhaustion criteria. The 2 linear and non-linear 2-parameter models can be used to estimate aerobic endurance in specific table tennis tests. © Georg Thieme Verlag KG Stuttgart · New York.

  14. Sister chromatid exchange and micronucleus frequency in human lymphocytes of 1,650 subjects in an Italian population: II. Contribution of sex, age, and lifestyle.

    Science.gov (United States)

    Barale, R; Chelotti, L; Davini, T; Del Ry, S; Andreassi, M G; Ballardin, M; Bulleri, M; He, J; Baldacci, S; Di Pede, F; Gemignani, F; Landi, S

    1998-01-01

    Sister chromatid exchange (SCE) and micronuclei (MN) analysis was carried out on 1,650 healthy individuals living in Pisa and in two nearby small cities, Cascina and Navacchio (Ca-Na). The effect of smoking on SCEs was linearly correlated with the number of cigarettes per day, and an increase of 7.3% SCEs was detectable for as few cigarettes as 1-10/day. Ex-smokers showed intermediate mean values of SCEs (8.09 +/- 1.88) in comparison with never smokers (7.54 +/- 1.61) and current smokers (8.45 +/- 1.94). Mean values of SCEs of ex-smokers decreased linearly with time of smoking cessation, reaching the mean values of never smokers within 8 years. The extent of SCE decrease was inversely proportional to the number of cigarettes previously smoked. No interaction between smoking habits and coffee or alcohol drinking on SCEs was observed. A borderline (P = 0.053) increase in mean SCE values in coffee drinkers (more than 3 cups/day) was found. The age effect on SCEs was remarkable in Ca-Na, but not in Pisa donors. Job type was not associated with significant modification of mean values of SCEs. Multiple logistic regression analysis revealed a statistically significant association between the proportion of high frequency cells (HCF) outliers and coffee consumption. Age and sex appeared to be by far the most important variables associated with modifications in MN frequency, which increased by 0.04 per thousand and 0.02 per thousand per year in males and females, respectively. Children and young donors (age < or = 40 years) showed lower MN frequency regardless of sex, whereas sex appeared to determine a significantly higher increase of MN only in females older than 40 years. In contrast, in males the MN rate by age tended to level off after the age of 30-50. MN frequencies of Pisa blue- and white-collar workers were statistically significantly higher than in students (+0.71 and +0.55 per thousand, respectively). Smoking did not determine any increase of MN frequency. A total

  15. Exchange Network

    Science.gov (United States)

    The Environmental Information Exchange Network (EIEN) is an Internet-based system used by state, tribal and territorial partners to securely share environmental and health information with one another and EPA.

  16. Specific microbial gene abundances and soil parameters contribute to C, N, and greenhouse gas process rates after land use change in Southern Amazonian Soils

    Directory of Open Access Journals (Sweden)

    Daniel Renato Lammel

    2015-10-01

    Full Text Available Ecological processes regulating soil carbon (C and nitrogen (N cycles are still poorly understood, especially in the world’s largest agricultural frontier in Southern Amazonia. We analyzed soil parameters in samples from pristine rainforest and after land use change to pasture and crop fields, and correlated them with abundance of functional and phylogenetic marker genes (amoA, nirK, nirS, norB, nosZ, nifH, mcrA, pmoA, and 16S/18S rRNA. Additionally, we integrated these parameters using path analysis and multiple regressions. Following forest removal, concentrations of soil C and N declined, and pH and nutrient levels increased, which influenced microbial abundances and biogeochemical processes. A seasonal trend was observed, suggesting that abundances of microbial groups were restored to near native levels after the dry winter fallow. Integration of the marker gene abundances with soil parameters using path analysis and multiple regressions provided good predictions of biogeochemical processes, such as the fluxes of NO3, N2O, CO2, and CH4. In the wet season, agricultural soil showed the highest abundance of nitrifiers (amoA and Archaea, however forest soils showed the highest abundances of denitrifiers (nirK, nosZ and high N, which correlated with increased N2O emissions. Methanogens (mcrA and methanotrophs (pmoA were more abundant in forest soil, but methane flux was highest in pasture sites, which was related to soil compaction. Rather than analyzing direct correlations, the data integration using multivariate tools provided a better overview of biogeochemical processes. Overall, in the wet season, land use change from forest to agriculture reduced the abundance of different functional microbial groups related to the soil C and N cycles; integrating the gene abundance data and soil parameters provided a comprehensive overview of these interactions. Path analysis and multiple regressions addressed the need for more comprehensive approaches

  17. Hydrogen exchange

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Rand, Kasper Dyrberg

    2016-01-01

    Hydrogen exchange (HX) monitored by mass spectrometry (MS) is a powerful analytical method for investigation of protein conformation and dynamics. HX-MS monitors isotopic exchange of hydrogen in protein backbone amides and thus serves as a sensitive method for probing protein conformation...... and dynamics along the entire protein backbone. This chapter describes the exchange of backbone amide hydrogen which is highly quenchable as it is strongly dependent on the pH and temperature. The HX rates of backbone amide hydrogen are sensitive and very useful probes of protein conformation......, as they are distributed along the polypeptide backbone and form the fundamental hydrogen-bonding networks of basic secondary structure. The effect of pressure on HX in unstructured polypeptides (poly-dl-lysine and oxidatively unfolded ribonuclease A) and native folded proteins (lysozyme and ribonuclease A) was evaluated...

  18. Serial tempering without exchange.

    Science.gov (United States)

    Nymeyer, Hugh

    2010-09-21

    Serial tempering is a computational method that turns the temperature T (or more generally any independent λ parameter) into a dynamical variable. It is shown that, under conditions for which this variable is fast, serial tempering is equivalent to the umbrella sampling method with a single effective potential. This equivalence is demonstrated using both a small one-dimensional system and a small solvated peptide. The suggestion is then made to replace the serial tempering protocol with the equivalent umbrella sampling calculation. This approach, serial tempering without exchange (STeWiE), has the same performance as serial tempering in the limit that exchanges are frequent, is simpler to implement, and has fewer adjustable parameters than conventional serial tempering. The equivalence of serial tempering and STeWiE also provides a convenient route for estimating and optimizing the performance of serial tempering simulations and other generalized-ensemble methods.

  19. Exchange Options

    NARCIS (Netherlands)

    Jamshidian, F.

    2007-01-01

    The contract is described and market examples given. Essential theoretical developments are introduced and cited chronologically. The principles and techniques of hedging and unique pricing are illustrated for the two simplest nontrivial examples: the classical Black-Scholes/Merton/Margrabe exchange

  20. Characterization of the atrazine sorption process on Andisol and Ultisol volcanic ash-derived soils: kinetic parameters and the contribution of humic fractions.

    Science.gov (United States)

    Báez, María E; Fuentes, Edwar; Espinoza, Jeannette

    2013-07-03

    Atrazine sorption was studied in six Andisol and Ultisol soils. Humic and fulvic acids and humin contributions were established. Sorption on soils was well described by the Freundlich model. Kf values ranged from 2.2-15.6 μg(1-1/n)mL(1/n)g⁻¹. The relevance of humic acid and humin was deduced from isotherm and kinetics experiments. KOC values varied between 221 and 679 mLg⁻¹ for these fractions. Fulvic acid presented low binding capacity. Sorption was controlled by instantaneous equilibrium followed by a time-dependent phase. The Elovich equation, intraparticle diffusion model, and a two-site nonequilibrium model allowed us to conclude that (i) there are two rate-limited phases in Andisols related to intrasorbent diffusion in organic matter and retarded intraparticle diffusion in the organo-mineral complex and that (ii) there is one rate-limited phase in Ultisols attributed to the mineral composition. The lower organic matter content of Ultisols and the slower sorption rate and mechanisms involved must be considered to assess the leaching behavior of atrazine.

  1. Application of cinchona-sulfonate-based chiral zwitterionic ion exchangers for the separation of proline-containing dipeptide rotamers and determination of on-column isomerization parameters from dynamic elution profiles

    Energy Technology Data Exchange (ETDEWEB)

    Wernisch, Stefanie, E-mail: stefanie.wernisch@univie.ac.at [Institute for Analytical Chemistry, University of Vienna, Währinger Straße 38, A-1090 Vienna (Austria); Trapp, Oliver, E-mail: trapp@oci.uni-heidelberg.de [Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg (Germany); Lindner, Wolfgang, E-mail: wolfgang.lindner@univie.ac.at [Institute for Analytical Chemistry, University of Vienna, Währinger Straße 38, A-1090 Vienna (Austria)

    2013-09-17

    Graphical abstract: -- Highlights: •X-Pro peptides produce interconverting elution profiles on zwitterionic stationary phases. •The cis–trans isomerization rate in solution is lower than in the chromatographic system. •Cinchona-based zwitterionic selectors apparently lower the isomerization barrier. •Rotamer separation is feasible <0 °C, enantiomer separation above room temperature. -- Abstract: The interconversion of cis and trans isomers of dipeptides containing C-terminal proline was studied by dynamic chromatography on zwitterionic chiral stationary phases at temperatures ranging from −15 °C to +45 °C The cis–trans isomers could be separated below 0 °C and above 0–10 °C plateau formation and peak coalescence phenomena occurred, which is characteristic for a dynamic process at the time-scale of partitioning. At and above room temperature, full coalescence was observed, which allowed separations of enantiomers without interference from interconversion effects. Analysis of the dynamic elution profiles of the interconverting peptides allowed the determination of isomerization rate constants and thermodynamic activation parameters (isomerization enthalpy, entropy and activation energy). In accordance with established results, isomerization rates and thermodynamic parameters were found to depend on the nature of the N-terminal amino acid. Isomerization barriers were only slightly lower than values determined with other methods but significant differences in the relative contributions of the activation enthalpy and entropy as well as isomerization rates pointed toward selector-moderated isomerization dynamics.

  2. Ion exchange equilibrium constants

    CERN Document Server

    Marcus, Y

    2013-01-01

    Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and

  3. The study of various parameters affecting the ion exchange of Cu2+, Zn2+, Ni2+, Cd2+, and Pb2+ from aqueous solution on Dowex 50W synthetic resin.

    Science.gov (United States)

    Pehlivan, Erol; Altun, Turkan

    2006-06-30

    A gel resin containing sulfonate groups (Dowex 50W) was investigated for its sorption properties towards copper, zinc, nickel, cadmium and lead metal ions. The use of selective ion exchange to recover metals from aqueous solution has been studied. The ion exchange behavior of five metals on Dowex 50W, depending on pH, temperature, and contact time and adsorbate amount was studied. Experimental measurements have been made on the batch sorption of toxic metals from aqueous solutions using cation exchanger Dowex 50W. The maximum recoveries (about 97%) Cu(2+), Zn(2+), Ni(2+), Cd(2+) and (about 80%) Pb(2+) were found at pH ranges 8-9. The amount of sorbed metal ion was calculated as 4.1, 4.6, 4.7, 4.8, and 4.7mequiv./gram dry resin for Pb(2+), Cu(2+), Zn(2+), Cd(2+), and Ni(2+), respectively. The precision of the method was examined at under optimum conditions. Selectivity increased in the series: Pb>Cd>Cu>Zn>Ni. It has been observed that, selectivity of the -SO(3)H group of the resin increases with atomic number, valance, degree of ionization of the exchanged metals. The equilibrium ion exchange capacity of resin for metal ions was measured and explored by using Freundlich and Langmuir isotherms. Langmuir type sorption isotherm was suitable for equilibrium studies.

  4. The study of various parameters affecting the ion exchange of Cu{sup 2+}, Zn{sup 2+}, Ni{sup 2+}, Cd{sup 2+}, and Pb{sup 2+} from aqueous solution on Dowex 50W synthetic resin

    Energy Technology Data Exchange (ETDEWEB)

    Pehlivan, Erol [Department of Chemical Engineering, Selcuk University, Campus, 42031 Konya (Turkey)]. E-mail: pehlivan@selcuk.edu.tr; Altun, Turkan [Department of Chemical Engineering, Selcuk University, Campus, 42031 Konya (Turkey)

    2006-06-30

    A gel resin containing sulfonate groups (Dowex 50W) was investigated for its sorption properties towards copper, zinc, nickel, cadmium and lead metal ions. The use of selective ion exchange to recover metals from aqueous solution has been studied. The ion exchange behavior of five metals on Dowex 50W, depending on pH, temperature, and contact time and adsorbate amount was studied. Experimental measurements have been made on the batch sorption of toxic metals from aqueous solutions using cation exchanger Dowex 50W. The maximum recoveries (about 97%) Cu{sup 2+}, Zn{sup 2+}, Ni{sup 2+}, Cd{sup 2+} and (about 80%) Pb{sup 2+} were found at pH ranges 8-9. The amount of sorbed metal ion was calculated as 4.1, 4.6, 4.7, 4.8, and 4.7 mequiv./gram dry resin for Pb{sup 2+}, Cu{sup 2+}, Zn{sup 2+}, Cd{sup 2+}, and Ni{sup 2+}, respectively. The precision of the method was examined at under optimum conditions. Selectivity increased in the series: Pb > Cd > Cu > Zn > Ni. It has been observed that, selectivity of the -SO{sub 3}H group of the resin increases with atomic number, valance, degree of ionization of the exchanged metals. The equilibrium ion exchange capacity of resin for metal ions was measured and explored by using Freundlich and Langmuir isotherms. Langmuir type sorption isotherm was suitable for equilibrium studies.

  5. Segmented heat exchanger

    Science.gov (United States)

    Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann

    2010-12-14

    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  6. Our International Art Exchange Project.

    Science.gov (United States)

    Cocciolone, Kathy R.

    1989-01-01

    Discusses an international art exchange project designed to teach fifth-grade students that the culture of a country is reflected in its art and that art is a universal language. Describes the contributions from Scotland, Mexico, Saudi Arabia, Egypt, Japan, and India. Points out ways to use materials in schools. (KO)

  7. Data Exchanges and Verifications Online (DEVO)

    Data.gov (United States)

    Social Security Administration — DEVO is the back-end application for processing SSN verifications and data exchanges. DEVO uses modern technology for parameter driven processing of both batch and...

  8. Productivity, Respiration, and Light-Response Parameters of World Grassland and Agroecosystems Derived From Flux-Tower Measurements

    NARCIS (Netherlands)

    Gilmanov, T.G.; Aires, L.; Barsca, V.; Baron, S.; Moors, E.J.; Jacobs, A.

    2010-01-01

    Grasslands and agroecosystems occupy one-third of the terrestrial area, but their contribution to the global carbon cycle remains uncertain. We used a set of 316 site-years of CO2 exchange measurements to quantify gross primary productivity, respiration, and light-response parameters of grasslands,

  9. Intra- and interspecific differences of 10 barley and 10 tomato cultivars in response to short-time UV-B radiation: A study analysing thermoluminescence, fluorescence, gas-exchange and biochemical parameters

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, Matthias, E-mail: mgilbert@rz.uni-leipzig.d [University of Leipzig, Institute of Biology I, Plant Physiology, Johannisallee 21-23, D-04103 Leipzig (Germany); Poers, Yvonne, E-mail: yvonne.poers@rz.hu-berlin.d [Humboldt University Berlin, Institute of Biology, Cell Biology, Invalidenstrasse 42, D-10115 Berlin (Germany); Humboldt University Berlin, Institute of Biology, Plant Physiology, Philippstrasse 13, D-10115 Berlin (Germany); Grover, Kirsten, E-mail: sandhyagro@gmx.d [University of Leipzig, Institute of Biology I, Plant Physiology, Johannisallee 21-23, D-04103 Leipzig (Germany); Weingart, Ilka, E-mail: sounso@googlemail.co [University of Leipzig, Institute of Biology I, Plant Physiology, Johannisallee 21-23, D-04103 Leipzig (Germany); Skotnica, Jiri, E-mail: skotnica2@seznam.c [University of Leipzig, Institute of Biology I, Plant Physiology, Johannisallee 21-23, D-04103 Leipzig (Germany); Grimm, Bernhard, E-mail: bernhard.grimm@rz.hu-berlin.d [Humboldt University Berlin, Institute of Biology, Plant Physiology, Philippstrasse 13, D-10115 Berlin (Germany); Seidlitz, Harald K., E-mail: harald.seidlitz@helmholtz-muenchen.d [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Soil Ecology, Department of Environmental Engineering, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany); Langebartels, Christian, E-mail: langebartels@helmholtz-muenchen.d [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Program Planning and Management Department, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany); Wilhelm, Christian, E-mail: cwilhelm@rz.uni-leipzig.d [University of Leipzig, Institute of Biology I, Plant Physiology, Johannisallee 21-23, D-04103 Leipzig (Germany)

    2009-05-15

    The impact of UV-B radiation on 10 genotypically different barley and tomato cultivars was tested in a predictive study to screen for potentially UV-tolerant accessions and to analyze underlying mechanisms for UV-B sensitivity. Plant response was analyzed by measuring thermoluminescence, fluorescence, gas exchange and antioxidant status. Generally, barley cultivars proved to be much more sensitive against UV-B radiation than tomato cultivars. Statistical cluster analysis could resolve two barley groups with distinct differences in reaction patterns. The UV-B sensitive group showed a stronger loss in PSII photochemistry and a lower gas-exchange performance and regulation after UV-B radiation compared to the more tolerant group. The results indicate that photosynthetic light and dark reactions have to play optimally in concert to render plants more tolerant against UV-B radiation. Hence, measuring thermoluminescence/fluorescence and gas exchange in parallel will have much higher potential in identifying tolerant cultivars and will help to understand the underlying mechanisms. - Mechanisms of UV-B tolerance and sensitivity in crop plants.

  10. Totalization Data Exchange (TDEX)

    Data.gov (United States)

    Social Security Administration — The Totalization Data Exchange (TDEX) process is an exchange between SSA and its foreign country partners to identify deaths of beneficiaries residing abroad. The...

  11. Detente: A Role for U.S.-Soviet Exchanges?

    Science.gov (United States)

    Herman, Paul F., Jr.

    The contribution of international exchanges (e.g., cultural activities, tourism, student exchange) to detente enhancement is assessed. International exchanges have a capacity for engendering trust and for providing cultural, political, and economic benefit, two characteristics of policy acts which tend to enhance detente. A comparison of four very…

  12. An analysis of the development of home exchange organisations ...

    African Journals Online (AJOL)

    This paper contributes to a better understanding of the home exchange phenomenon by considering the historical developmentof the home exchange intermediation processes, membership profiles and the role of the media. The Internet has enableda more interactive process and facilitated home exchange kernels which, ...

  13. New approaches for the calibration of exchange-energy densities in local hybrid functionals.

    Science.gov (United States)

    Maier, Toni M; Haasler, Matthias; Arbuznikov, Alexei V; Kaupp, Martin

    2016-08-21

    The ambiguity of exchange-energy densities is a fundamental challenge for the development of local hybrid functionals, or of other functionals based on a local mixing of exchange-energy densities. In this work, a systematic construction of semi-local calibration functions (CFs) for adjusting the exchange-energy densities in local hybrid functionals is provided, which directly links a given CF to an underlying semi-local exchange functional, as well as to the second-order gradient expansion of the exchange hole. Using successive steps of integration by parts allows the derivation of correction terms of increasing order, resulting in more and more complicated but also more flexible CFs. We derive explicit first- and second-order CFs (pig1 and pig2) based on B88 generalized-gradient approximation (GGA) exchange, and a first-order CF (tpig1) based on τ-dependent B98 meta-GGA exchange. We combine these CFs with different long-range damping functions and evaluate them for calibration of LDA, B88 GGA, and TPSS meta-GGA exchange-energy densities. Based on a minimization of unphysical nondynamical correlation contributions in three noble-gas dimer potential-energy curves, free parameters in the CFs are optimized, and performance of various approaches in the calibration of different exchange-energy densities is compared. Most notably, the second-order pig2 CF provides the largest flexibility with respect to the diffuseness of the damping function. This suggests that higher-order CFs based on the present integration-by-parts scheme may be particularly suitable for the flexible construction of local hybrid functionals.

  14. Application of ground-to-air heat exchanger for preheating of supply air

    Science.gov (United States)

    Sorokins, Juris; Borodinecs, Anatolijs; Zemitis, Jurgis

    2017-10-01

    This study focuses on assessing the contribution of the passive ground-coupled air heat exchanger system to decreasing the energy consumption of air conditioning and ventilation systems for office buildings in the Latvian climate conditions. The theoretical part of the thesis deals with methods of office building ventilation, supply air preheating and heat recovery as well as particularities of using ground-coupled air heat exchangers, their design parameters and their joint impact on the thermal performance. The engineering project part includes a ventilation system for an office building with an integrated ground-coupled air heat exchanger. By simulating energy consumption of the ventilation system for a duration of one year, the thesis analyzes the contribution of the heat exchanger to the overall energy consumption, which totals 9.53 MWh and 4.02 MWh a year, according to the desired parameters of the indoor climate. The possible alternative heat recovery solutions are investigated to reach by European Regional Development Fund project Nr.1.1.1.1/16/A/048 “NEARLY ZERO ENERGY SOLUTIONS FOR UNCLASSIFIED BUILDINGS”.

  15. Mineral Separation in a CELSS by Ion-exchange Chromatography

    Science.gov (United States)

    Ballou, E. V.; Spitze, L. A.; Wong, F. W.; Wydeven, T.; Johnson, C. C.

    1982-01-01

    Operational parameters pertinent to ion exchange chromatography separation were identified. The experiments were performed with 9 mm diameter ion exchange columns and conventional column accessories. The cation separation beds were packed with AG 50W-X2 strong acid cation exchange resin in H(+) form and 200-400 dry mesh particle size. The stripper beds used in some experiments were packed with AG 1-XB strong base cation exchange resin in OH(-) form and 200-400 dry mesh particle size.

  16. VOLATILITY OF EXCHANGE RATE IN THE CONTEXT OF FOREIGN TRADE

    Directory of Open Access Journals (Sweden)

    Oleg STRATULAT

    2016-09-01

    Full Text Available Moderate fluctuation of the exchange rate, basically in its floating regime is considered normality. Meanwhile,excessive volatility of the exchange rate is an issue for many countries. Its elimination is directed to foreign trade, which, through essential exports, followed by significant currency inflows, contribute to the stability of exchange rates. Unfortunately, Moldova’s foreign trade has become a key factor in maintaining the stability of foreign exchange.

  17. Research into the Physiology of Cerebrospinal Fluid Reaches a New Horizon: Intimate Exchange between Cerebrospinal Fluid and Interstitial Fluid May Contribute to Maintenance of Homeostasis in the Central Nervous System.

    Science.gov (United States)

    Matsumae, Mitsunori; Sato, Osamu; Hirayama, Akihiro; Hayashi, Naokazu; Takizawa, Ken; Atsumi, Hideki; Sorimachi, Takatoshi

    2016-07-15

    Cerebrospinal fluid (CSF) plays an essential role in maintaining the homeostasis of the central nervous system. The functions of CSF include: (1) buoyancy of the brain, spinal cord, and nerves; (2) volume adjustment in the cranial cavity; (3) nutrient transport; (4) protein or peptide transport; (5) brain volume regulation through osmoregulation; (6) buffering effect against external forces; (7) signal transduction; (8) drug transport; (9) immune system control; (10) elimination of metabolites and unnecessary substances; and finally (11) cooling of heat generated by neural activity. For CSF to fully mediate these functions, fluid-like movement in the ventricles and subarachnoid space is necessary. Furthermore, the relationship between the behaviors of CSF and interstitial fluid in the brain and spinal cord is important. In this review, we will present classical studies on CSF circulation from its discovery over 2,000 years ago, and will subsequently introduce functions that were recently discovered such as CSF production and absorption, water molecule movement in the interstitial space, exchange between interstitial fluid and CSF, and drainage of CSF and interstitial fluid into both the venous and the lymphatic systems. Finally, we will summarize future challenges in research. This review includes articles published up to February 2016.

  18. Parameter Estimation

    DEFF Research Database (Denmark)

    Sales-Cruz, Mauricio; Heitzig, Martina; Cameron, Ian

    2011-01-01

    In this chapter the importance of parameter estimation in model development is illustrated through various applications related to reaction systems. In particular, rate constants in a reaction system are obtained through parameter estimation methods. These approaches often require the application...... of optimisation techniques coupled with dynamic solution of the underlying model. Linear and nonlinear approaches to parameter estimation are investigated. There is also the application of maximum likelihood principles in the estimation of parameters, as well as the use of orthogonal collocation to generate a set...... of algebraic equations as the basis for parameter estimation.These approaches are illustrated using estimations of kinetic constants from reaction system models....

  19. Sea-ice melt CO2-carbonate chemistry in the western Arctic Ocean: meltwater contributions to air-sea CO2 gas exchange, mixed layer properties and rates of net community production under sea ice

    Science.gov (United States)

    Bates, N. R.; Garley, R.; Frey, K. E.; Shake, K. L.; Mathis, J. T.

    2014-01-01

    The carbon dioxide (CO2)-carbonate chemistry of sea-ice melt and co-located, contemporaneous seawater has rarely been studied in sea ice covered oceans. Here, we describe the CO2-carbonate chemistry of sea-ice melt (both above sea ice as "melt ponds" and below sea ice as "interface waters") and mixed layer properties in the western Arctic Ocean in the early summer of 2010 and 2011. At nineteen stations, the salinity (~ 0.5 to 1500 μatm) with the majority of melt ponds acting as potentially strong sources of CO2 to the atmosphere. The pH of melt pond waters was also highly variable ranging from mildly acidic (6.1 to 7) to slightly more alkaline than underlying seawater (8 to 10.7). All of observed melt ponds had very low (pH/Ωaragonite than the co-located mixed layer beneath. Sea-ice melt thus contributed to the suppression of mixed layer pCO2 enhancing the surface ocean's capacity to uptake CO2 from the atmosphere. Meltwater contributions to changes in mixed-layer DIC were also used to estimate net community production rates (mean of 46.9 ±29.8 g C m-2 for the early-season period) under sea-ice cover. Although sea-ice melt is a transient seasonal feature, above-ice melt pond coverage can be substantial (10 to > 50%) and under-ice interface melt water is ubiquitous during this spring/summer sea-ice retreat. Our observations contribute to growing evidence that sea-ice CO2-carbonate chemistry is highly variable and its contribution to the complex factors that influence the balance of CO2 sinks and sources (and thereby ocean acidification) is difficult to predict in an era of rapid warming and sea ice loss in the Arctic Ocean.

  20. Sea-ice melt CO2-carbonate chemistry in the western Arctic Ocean: meltwater contributions to air-sea CO2 gas exchange, mixed-layer properties and rates of net community production under sea ice

    Science.gov (United States)

    Bates, N. R.; Garley, R.; Frey, K. E.; Shake, K. L.; Mathis, J. T.

    2014-12-01

    The carbon dioxide (CO2)-carbonate chemistry of sea-ice melt and co-located, contemporaneous seawater has rarely been studied in sea-ice-covered oceans. Here, we describe the CO2-carbonate chemistry of sea-ice melt (both above sea-ice as "melt ponds" and below sea-ice as "interface waters") and mixed-layer properties in the western Arctic Ocean in the early summer of 2010 and 2011. At 19 stations, the salinity (∼0.5 to 1500 μatm) with the majority of melt ponds acting as potentially strong sources of CO2 to the atmosphere. The pH of melt pond waters was also highly variable ranging from mildly acidic (6.1 to 7) to slightly more alkaline than underlying seawater (>8.2 to 10.8). All of the observed melt ponds had very low (pH/Ωaragonite than the co-located mixed layer beneath. Sea-ice melt thus contributed to the suppression of mixed-layer pCO2, thereby enhancing the surface ocean's capacity to uptake CO2 from the atmosphere. Our observations contribute to growing evidence that sea-ice CO2-carbonate chemistry is highly variable and its contribution to the complex factors that influence the balance of CO2 sinks and sources (and thereby ocean acidification) is difficult to predict in an era of rapid warming and sea-ice loss in the Arctic Ocean.

  1. VT Telephone Exchange Boundaries

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The UtilityTelecom_EXCHANGE represents Vermont Telephone Exchange boundaries as defined by the VT Public Service Board. The original data was...

  2. Predicting the distribution of whey protein fouling in a plate heat exchanger using the kinetic parameters of the thermal denaturation reaction of β-lactoglobulin and the bulk temperature profiles.

    Science.gov (United States)

    Blanpain-Avet, P; André, C; Khaldi, M; Bouvier, L; Petit, J; Six, T; Jeantet, R; Croguennec, T; Delaplace, G

    2016-12-01

    Fouling of plate heat exchangers (PHE) is a severe problem in the dairy industry, notably because the relationship between the build-up of protein fouling deposits and the chemical reactions taking place in the fouling solution has not yet been fully elucidated. Experiments were conducted at pilot scale in a corrugated PHE, and fouling deposits were generated using a model β-lactoglobulin (β-LG) fouling solution for which the β-LG thermal denaturation reaction constants had been previously determined experimentally. Then 18 different bulk temperature profiles within the PHE were imposed. Analysis of the fouling runs shows that the dry deposit mass per channel versus the ratio R=kunf/kagg (with kunf and kagg representing, respectively, the unfolding and aggregation rate constants computed from both the identification of the β-LG thermal denaturation process and knowledge of the imposed bulk temperature profile into the PHE channel) is able to gather reasonably well the experimental fouling mass data into a unique master curve. This type of representation of the results clearly shows that the heat-induced reactions (unfolding and aggregation) of the various β-LG molecular species in the bulk fluid are essential to capture the trend of the fouling mass distribution inside a PHE. This investigation also illustrates unambiguously that the release of the unfolded β-LG (also called β-LG molten globule) within the bulk fluid (and the absence of its consumption in the form of aggregates) is a key phenomenon that controls the extent of protein fouling as well as its location inside the PHE. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  3. Modelling boreal forest CO{sub 2} exchange and seasonality

    Energy Technology Data Exchange (ETDEWEB)

    Thum, T.

    2009-07-01

    Man-induced climate change has raised the need to predict the future climate and its feedback to vegetation. These are studied with global climate models; to ensure the reliability of these predictions, it is important to have a biosphere description that is based upon the latest scientific knowledge. This work concentrates on the modelling of the CO{sub 2} exchange of the boreal coniferous forest, studying also the factors controlling its growing season and how these can be used in modelling. In addition, the modelling of CO{sub 2} gas exchange at several scales was studied. A canopy-level CO{sub 2} gas exchange model was developed based on the biochemical photosynthesis model. This model was first parameterized using CO{sub 2} exchange data obtained by eddy covariance (EC) measurements from a Scots pine forest at Sodankylae. The results were compared with a semi-empirical model that was also parameterized using EC measurements. Both of the models gave satisfactory results. The biochemical canopy-level model was further parameterized at three other coniferous forest sites located in Finland and Sweden. At all the sites, the two most important biochemical model parameters showed seasonal behaviour, i.e., their temperature responses changed according to the season. Modelling results were improved when these changeover dates were related to temperature indices. During summer-time the values of the biochemical model parameters were similar at all the four sites. Different control factors for CO{sub 2} gas exchange were studied at the four coniferous forests, including how well these factors can be used to predict the initiation and cessation of the CO{sub 2} uptake. Temperature indices, atmospheric CO{sub 2} concentration, surface albedo and chlorophyll fluorescence (CF) were all found to be useful and have predictive power. In Finnish Lapland a trend toward an earlier start of the CO{sub 2} uptake in spring was also observed. In addition, a detailed simulation study

  4. Ideal Heat Exchange System

    Science.gov (United States)

    Tsirlin, A. M.

    2017-09-01

    The requirements with which a heat exchange system should comply in order that at certain values of the total contact surface and heat load the entropy production in it should be minimal have been determined. It has been shown that this system can serve as a standard for real systems of irreversible heat exchange. We have found the conditions for physical realizability of a heat exchange system in which heat exchange occurs by a law linear with respect to the temperature difference between contacting flows. Analogous conditions are given without deriving for the case of heat exchange by the Fourier law.

  5. Resolution exchange simulation.

    Science.gov (United States)

    Lyman, Edward; Ytreberg, F Marty; Zuckerman, Daniel M

    2006-01-20

    We extend replica-exchange simulation in two ways and apply our approaches to biomolecules. The first generalization permits exchange simulation between models of differing resolution--i.e., between detailed and coarse-grained models. Such "resolution exchange" can be applied to molecular systems or spin systems. The second extension is to "pseudoexchange" simulations, which require little CPU usage for most levels of the exchange ladder and also substantially reduce the need for overlap between levels. Pseudoexchanges can be used in either replica or resolution exchange simulations. We perform efficient, converged simulations of a 50-atom peptide to illustrate the new approaches.

  6. Social power in exchange theories: Homans's and Blau's considerations of the relationship between the power and the exchange

    Directory of Open Access Journals (Sweden)

    Mentus Vladimir

    2014-01-01

    Full Text Available Since social exchange is one of the key concepts in the social life, the exchange theory can be one of the most important within sociology. Also, another crucial concept to the social reality and social sciences is social power. The theory of social exchange has provided a significant contribution to the study of power, however, this contribution of theorists who belong to exchange paradigm is completely neglected within scientific literature. Therefore, the subject of this paper is social power from the perspective of the exchange theory, particularly the theories of George Homans and Peter Blau. The structure of the paper is as follows: first, the basic principles of the exchange theory are briefly described, then the relationship between concepts of social power and exchange is presented, and finally Homans's and Blau's interpretations of that relationship are exposed, along with the critical scrutiny of these interpretations.

  7. The Radioecology Exchange

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, Catherine L.; Beresford, Nicholas A.; Patel, Sabera; Wells, Claire; Howard, Brenda J. [NERC Centre for Ecology and Hydrology, CEH Lancaster, Lancaster Environment Centre, Library Av., Bailrigg, Lancaster, LA1 4AP (United Kingdom); Mora, Juan Carlos; Real, Almudena [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avenida complutense 22, Madrid, 28040 (Spain); Beaugelin-Seiller, Karine; Gilbin, Rodolphe; Hinton, Thomas [IRSN-Institut de Radioprotection et de Surete Nucleaire, 31, Avenue de la Division Leclerc, 92260 Fontenay-Aux-Roses (France); Vesterbacka, Pia; Muikku, Maarit; Outola, Iisa [Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881 Helsinki (Finland); Skuterud, Lavrans; AlbumYtre-Eide, Martin [Norwegian Radiation Protection Authority, Grini Naeringspark 13, Oesteraas, 1332 (Norway); Bradshaw, Clare; Stark, Karolina; Jaeschke, Ben [Stockholms Universitet, Universitetsvaegen 10, Stockholm, 10691 (Sweden); Oughton, Deborah; Skipperud, Lindis [NMBU Norwegian University of Life Science P.O. Box 5003N-1432 Aas, Oslo (Norway); Vandenhove, Hildegarde; Vanhoudt, Nathalie [SCK.CEN, Studiecentrum voor Kernenergie/Centre d' Etude de l' Energie Nucleaire, Avenue Herrmann-Debroux 40, BE-1160 Brussels (Belgium); Willrodt, Christine; Steiner, Martin [Bundesamt fuer Strahlenschutz, Willy-Brandt-Strasse 5, 38226 Salzgitter (Germany)

    2014-07-01

    The Radioecology Exchange (www.radioecology-exchange.org) was created in 2011 under the EU FP7 STAR (Strategy for Allied Radioecology) network of excellence. The project aims to integrate the research efforts on radioecology of nine European organisations into a sustainable network. The web site (together with associated Twitter feeds and Facebook page) currently provides the gateway to project outputs and other on-line radiation protection and radioecological resources. In 2013, the EU FP7 COMET (Coordination and implementation of a pan-European instrument for radioecology) project commenced; it aims to strengthen research on the impact of radiation on man and the environment. COMET includes the STAR partners with the addition of one Japanese and two Ukrainian research institutes. As STAR and COMET interact closely together and with the European Radioecology Alliance (www.er-alliance.org/), the Radioecology Exchange will be modified to become an international 'hub' for information related to radioecology. Project specific information will be hosted on separate web sites www.star-radioecology.org and www.comet-radioecology.org. This paper will present an overview of the resources hosted on the Radioecology Exchange inviting other scientists to contribute. Highlighted aspects of the site include: Social media (News blog, Twitter, Facebook) - Items announcing project outputs, training courses, jobs, studentships etc. Virtual laboratory - Information which encourages integration through joint research and integrated use of data and sample materials. These pages will focus on three categories: (1) Methodological: descriptions and video clips of commonly used analytical methods and protocols and the procedures used in STAR and COMET; (2) Informative: databases made available by STAR/COMET partners together with details of sample archives held. Fact-sheets on radio-ecologically important radionuclides and 'topical descriptions' which show absorbed

  8. Analysis of Leader Member Exchange

    Directory of Open Access Journals (Sweden)

    Adi Santoso

    2016-10-01

    Full Text Available This research aims to find out how the relationship of superiors and subordinates works or we call it, LEADER MEMBER EXCHANGE (LMX in another term. The object of this research is an Integrated Nursing Home for Impaired Speech and Hearing (INISPH, ''Meohai” Kendari, with 5 superiors and subordinates of this institution as the research informants. The method used in this research is descriptive qualitative analysis. The research found that the relationship of superiors and subordinates or Leader Member Exchange (LMX, has been well-intertwined, based on the affection, loyalty, enormous contribution, and respect one another toward the profession done in creating a close relationship to achieve the goal.DOI: 10.15408/etk.v15i2.3244

  9. Phase exposure-dependent exchange

    Science.gov (United States)

    Ginn, T. R.; Schreyer, L. G.; Zamani, K.

    2017-01-01

    Solutes and suspended material often experience delays during exchange between phases one of which may be moving. Consequently transport often exhibits combined effects of advection/dispersion, and delays associated with exchange between phases. Such processes are ubiquitous and include transport in porous/fractured media, watersheds, rivers, forest canopies, urban infrastructure systems, and networks. Upscaling approaches often treat the transport and delay mechanisms together, yielding macroscopic "anomalous transport" models. When interaction with the immobile phase is responsible for the delays, it is not the transport that is anomalous, but the lack of it, due to delays. We model such exchanges with a simple generalization of first-order kinetics completely independent of transport. Specifically, we introduce a remobilization rate coefficient that depends on the time in immobile phase. Memory-function formulations of exchange (with or without transport) can be cast in this framework, and can represent practically all time-nonlocal mass balance models including multirate mass transfer and its equivalent counterparts in the continuous time random walk and time-fractional advection dispersion formalisms, as well as equilibrium exchange. Our model can address delayed single-/multievent remobilizations as in delay-differential equations and periodic remobilizations that may be useful in sediment transport modeling. It is also possible to link delay mechanisms with transport if so desired, or to superpose an additional source of nonlocality through the transport operator. This approach allows for mechanistic characterization of the mass transfer process with measurable parameters, and the full set of processes representable by these generalized kinetics is a new open question.

  10. 75 FR 41017 - Political Contributions by Certain Investment Advisers

    Science.gov (United States)

    2010-07-14

    ... Exchange Commission 17 CFR Part 275 Political Contributions by Certain Investment Advisers; Final Rule #0... Investment Advisers AGENCY: Securities and Exchange Commission. ACTION: Final rule. SUMMARY: The Securities and Exchange Commission is adopting a new rule under the Investment Advisers Act of 1940 that...

  11. Inventory parameters

    CERN Document Server

    Sharma, Sanjay

    2017-01-01

    This book provides a detailed overview of various parameters/factors involved in inventory analysis. It especially focuses on the assessment and modeling of basic inventory parameters, namely demand, procurement cost, cycle time, ordering cost, inventory carrying cost, inventory stock, stock out level, and stock out cost. In the context of economic lot size, it provides equations related to the optimum values. It also discusses why the optimum lot size and optimum total relevant cost are considered to be key decision variables, and uses numerous examples to explain each of these inventory parameters separately. Lastly, it provides detailed information on parameter estimation for different sectors/products. Written in a simple and lucid style, it offers a valuable resource for a broad readership, especially Master of Business Administration (MBA) students.

  12. Adaptively Compressed Exchange Operator

    CERN Document Server

    Lin, Lin

    2016-01-01

    The Fock exchange operator plays a central role in modern quantum chemistry. The large computational cost associated with the Fock exchange operator hinders Hartree-Fock calculations and Kohn-Sham density functional theory calculations with hybrid exchange-correlation functionals, even for systems consisting of hundreds of atoms. We develop the adaptively compressed exchange operator (ACE) formulation, which greatly reduces the computational cost associated with the Fock exchange operator without loss of accuracy. The ACE formulation does not depend on the size of the band gap, and thus can be applied to insulating, semiconducting as well as metallic systems. In an iterative framework for solving Hartree-Fock-like systems, the ACE formulation only requires moderate modification of the code, and can be potentially beneficial for all electronic structure software packages involving exchange calculations. Numerical results indicate that the ACE formulation can become advantageous even for small systems with tens...

  13. Laser Processed Heat Exchangers

    Science.gov (United States)

    Hansen, Scott

    2017-01-01

    The Laser Processed Heat Exchanger project will investigate the use of laser processed surfaces to reduce mass and volume in liquid/liquid heat exchangers as well as the replacement of the harmful and problematic coatings of the Condensing Heat Exchangers (CHX). For this project, two scale unit test articles will be designed, manufactured, and tested. These two units are a high efficiency liquid/liquid HX and a high reliability CHX.

  14. Microsoft Exchange 2013 cookbook

    CERN Document Server

    Van Horenbeeck, Michael

    2013-01-01

    This book is a practical, hands-on guide that provides the reader with a number of clear, step-by-step exercises.""Microsoft Exchange 2013 Cookbook"" is targeted at network administrators who deal with the Exchange server in their day-to-day jobs. It assumes you have some practical experience with previous versions of Exchange (although this is not a requirement), without being a subject matter expert.

  15. Information exchanges in cournot duopolies

    Directory of Open Access Journals (Sweden)

    Faíña Medín J. Andrés

    2003-01-01

    Full Text Available In this paper we analyze the profitability of information sharing among Cournot oligopolists receiving private information about random demand. We model the random demand as a linear demand having, 1 an unknown intercept, and 2 an unknown slope. In each of these two scenarios, firms observe private signals about the unknown parameter. We show that in the scenario-1, if the private signal observed by firms is accurate enough, information exchange is profitable and in the scenario-2, if there is a sufficiently large variation in the demand slope and private signals are accurate enough, firms earn strictly higher profits by sharing their information rather than keeping it private.

  16. Microtube strip heat exchanger

    Science.gov (United States)

    Doty, F. D.

    1991-07-01

    During the last quarter, Doty Scientific, Inc. (DSI) continued to make progress on the microtube strip (MTS) heat exchanger. The DSI completed a heat exchanger stress analysis of the ten-module heat exchanger bank; and performed a shell-side flow inhomogeneity analysis of the three-module heat exchanger bank. The company produced 50 tubestrips using an in-house CNC milling machine and began pressing them onto tube arrays. The DSI revised some of the tooling required to encapsulate a tube array and press tubestrips into the array to improve some of the prototype tooling.

  17. Comparison of sampling efficiency between simulated tempering and replica exchange

    OpenAIRE

    Zhang, Cheng; Ma, Jianpeng

    2008-01-01

    We compared the sampling efficiency of simulated tempering and replica exchange. Our results indicate that simulated tempering is superior to replica exchange if the parameters for temperature transition in simulated tempering are adjusted to be proportional to the partition function. It is shown that, in simulated tempering, the rate of traversing energy space of different temperatures is much higher than that in replica exchange, especially in the case of low tempering frequency and∕or larg...

  18. Comparison of sampling efficiency between simulated tempering and replica exchange.

    Science.gov (United States)

    Zhang, Cheng; Ma, Jianpeng

    2008-10-07

    We compared the sampling efficiency of simulated tempering and replica exchange. Our results indicate that simulated tempering is superior to replica exchange if the parameters for temperature transition in simulated tempering are adjusted to be proportional to the partition function. It is shown that, in simulated tempering, the rate of traversing energy space of different temperatures is much higher than that in replica exchange, especially in the case of low tempering frequency and/or larger temperature separations.

  19. GRUNDTVIG in transnational exchange

    DEFF Research Database (Denmark)

    Grundtvig in transnational exchange is the report from the seminar in december 2015 in cooperation with University of Cape Town and University of Hamburg.......Grundtvig in transnational exchange is the report from the seminar in december 2015 in cooperation with University of Cape Town and University of Hamburg....

  20. Education and Industry Exchange

    Science.gov (United States)

    Webb, Gerald A.

    1974-01-01

    Through an exchange plan a school representative worked at the personnel counter of a local company, and a supervisor from that company worked with counselors, faculty, administrators, and students from the local school. The exchange of ideas and insights were of benefit to the school and the company. (KP)

  1. A meson exchange model for the YN interaction

    Energy Technology Data Exchange (ETDEWEB)

    J. Haidenbauer; W. Melnitchouk; J. Speth

    2001-09-01

    We present a new model for the hyperon-nucleon (Lambda N, Sigma N) interaction, derived within the meson exchange framework. The model incorporates the standard one boson exchange contributions of the lowest pseudoscalar and vector meson multiplets with coupling constants fixed by SU(6) symmetry relations. In addition - as the main feature of the new model - the exchange of two correlated pions or kaons, both in the scalar-isoscalar (sigma) and vector-isovector (rho) channels, is included.

  2. Contribution to the study of the exchanges to the interface liquid bubble, resulting from an ejector venturi, for the treatment of dust; Contribution a l'etude des echanges a l'interface bulle liquide, issue d'un ejecteur venturi, horizontal en vue du traitement des poussieres

    Energy Technology Data Exchange (ETDEWEB)

    Giovannacci, D.

    2002-06-15

    A great number of industrial processes generate aerosols that the legislation prohibited to reject too great quantities (Decree no 98-360, 6 may 1998). Among the processes of elimination but also of recovery of these pollutants, washing by means of selective solvent is widespread. This operation is realized in contactors gas-liquid that one can classify out of absorbers with columns and absorbers venturi. Among the latter, one distinguishes the ejector venturi, the venturi high energy and the venturi with emulsion. In this work, we proposed to study the ejector venturi on the plans of hydrodynamics and transfer of matter, in the case of pollutants in the form of dust. At the time of the hydrodynamic study, we determine experimentally using fast camera the characteristics of the interface, the surface of exchange a and the diameter of the bubbles. We then could establish the law of distribution of the diameters of the bubbles. The introduction of a model of evolution in three phases of the current of bubbles enabled us to understand the evolution of the diameter during the course of the bubble and to characterize the influence of coalescence. With regard to the study of transfer of matter, we introduced a new model characterizing the trapping of dust included into bubbles. The dominating mechanism in the trapping is then with the inertial effects with the range of diameter of dust [ 2;4 ] {mu}m for which the trapping is optimum. We measured in experiments the effectiveness of trapping of the ejector, and its variations with the temperature of two effluents, the time of course and the density of the particles. The results from this study make it possible to work out a new type of particle filter, based on the technique of the ejector venturi. (author)

  3. STEP - Product Model Data Sharing and Exchange

    DEFF Research Database (Denmark)

    Kroszynski, Uri

    1998-01-01

    - Product Data Representation and Exchange", featuring at present some 30 released parts, and growing continuously. Many of the parts are Application Protocols (AP). This article presents an overview of STEP, based upon years of involvement in three ESPRIT projects, which contributed to the development...

  4. Heat exchanger design handbook

    CERN Document Server

    Thulukkanam, Kuppan

    2013-01-01

    Completely revised and updated to reflect current advances in heat exchanger technology, Heat Exchanger Design Handbook, Second Edition includes enhanced figures and thermal effectiveness charts, tables, new chapter, and additional topics--all while keeping the qualities that made the first edition a centerpiece of information for practicing engineers, research, engineers, academicians, designers, and manufacturers involved in heat exchange between two or more fluids.See What's New in the Second Edition: Updated information on pressure vessel codes, manufacturer's association standards A new c

  5. Anion exchange membrane

    Science.gov (United States)

    Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus

    2013-05-07

    An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

  6. Exergo-ecological evaluation of heat exchanger

    Directory of Open Access Journals (Sweden)

    Stanek Wojciech

    2014-01-01

    Full Text Available Thermodynamic optimization of thermal devices requires information about the influence of operational and structural parameters on its behaviour. The interconnections among parameters can be estimated by tools such as CFD, experimental statistic of the deviceetc. Despite precise and comprehensive results obtained by CFD, the time of computations is relatively long. This disadvantage often cannot be accepted in case of optimization as well as online control of thermal devices. As opposed to CFD the neural network or regression is characterized by short computational time, but does not take into account any physical phenomena occurring in the considered process. The CFD model of heat exchanger was built using commercial package Fluent/Ansys. The empirical model of heat exchanger has been assessed by regression and neural networks based on the set of pseudo-measurements generated by the exact CFD model. In the paper, the usage of the developed empirical model of heat exchanger for the minimisation of TEC is presented. The optimisationconcerns operational parameters of heat exchanger. The TEC expresses the cumulative exergy consumption of non-renewable resources. The minimization of the TEC is based on the objective function formulated by Szargut. However, the authors extended the classical TEC by the introduction of the exergy bonus theory proposed by Valero. The TEC objective function fulfils the rules of life cycle analysis because it contains the investment expenditures (measured by the cumulative exergy consumption of non-renewable natural resources, the operation of devices and the final effects of decommissioning the installation.

  7. Shell-and-double concentric-tube heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Bougriou, Cherif; Baadache, Khireddine [University of Batna, Department of Mechanics, Batna (Algeria)

    2010-03-15

    This study concerns a new type of heat exchangers, which is that of shell-and-double concentric-tube heat exchangers. These heat exchangers can be used in many specific applications such as air conditioning, waste heat recovery, chemical processing, pharmaceutical industries, power production, transport, distillation, food processing, cryogenics, etc. The case studies include both design calculations and performance calculations. It is demonstrated that the relative diameter sizes of the two tubes with respect to each other are the most important parameters that influence the heat exchanger size. (orig.)

  8. Data Exchange Inventory System (DEXI)

    Data.gov (United States)

    Social Security Administration — Enterprise tool used to identify data exchanges occurring between SSA and our trading partners. DEXI contains information on both incoming and outgoing exchanges and...

  9. Microplate Heat Exchanger Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a microplate heat exchanger for cryogenic cooling systems used for continuous flow distributed cooling systems, large focal plane arrays, multiple cooling...

  10. Exchange Risk Management Policy

    CERN Document Server

    2005-01-01

    At the Finance Committee of March 2005, following a comment by the CERN Audit Committee, the Chairman invited the Management to prepare a document on exchange risk management policy. The Finance Committee is invited to take note of this document.

  11. HUD Exchange Grantee Database

    Data.gov (United States)

    Department of Housing and Urban Development — The About Grantees section of the HUD Exchange brings up contact information, reports, award, jurisdiction, and location data for organizations that receive HUD...

  12. NASA Earth Exchange (NEX)

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA Earth Exchange (NEX) represents a new platform for the Earth science community that provides a mechanism for scientific collaboration and knowledge sharing....

  13. Anion exchange polymer electrolytes

    Science.gov (United States)

    Kim, Yu Seung; Kim, Dae Sik

    2015-06-02

    Anion exchange polymer electrolytes that include guanidinium functionalized polymers may be used as membranes and binders for electrocatalysts in preparation of anodes for electrochemical cells such as solid alkaline fuel cells.

  14. NMR Analysis of Amide Hydrogen Exchange Rates in a Pentapeptide-Repeat Protein from A. thaliana.

    Science.gov (United States)

    Xu, Shenyuan; Ni, Shuisong; Kennedy, Michael A

    2017-05-23

    At2g44920 from Arabidopsis thaliana is a pentapeptide-repeat protein (PRP) composed of 25 repeats capped by N- and C-terminal α-helices. PRP structures are dominated by four-sided right-handed β-helices typically consisting of mixtures of type II and type IV β-turns. PRPs adopt repeated five-residue (Rfr) folds with an Rfr consensus sequence (STAV)(D/N)(L/F)(S/T/R)(X). Unlike other PRPs, At2g44920 consists exclusively of type II β-turns. At2g44920 is predicted to be located in the thylakoid lumen although its biochemical function remains unknown. Given its unusual structure, we investigated the biophysical properties of At2g44920 as a representative of the β-helix family to determine if it had exceptional global stability, backbone dynamics, or amide hydrogen exchange rates. Circular dichroism measurements yielded a melting point of 62.8°C, indicating unexceptional global thermal stability. Nuclear spin relaxation measurements indicated that the Rfr-fold core was rigid with order parameters ranging from 0.7 to 0.9. At2g44920 exhibited a striking range of amide hydrogen exchange rates spanning 10 orders of magnitude, with lifetimes ranging from minutes to several months. A weak correlation was found among hydrogen exchange rates, hydrogen bonding energies, and amino acid solvent-accessible areas. Analysis of contributions from fast (approximately picosecond to nanosecond) backbone dynamics to amide hydrogen exchange rates revealed that the average order parameter of amides undergoing fast exchange was significantly smaller compared to those undergoing slow exchange. Importantly, the activation energies for amide hydrogen exchange were found to be generally higher for the slowest exchanging amides in the central Rfr coil and decreased toward the terminal coils. This could be explained by assuming that the concerted motions of two preceding or following coils required for hydrogen bond disruption and amide hydrogen exchange have a higher activation energy

  15. Building Capacity for Global Education in a School Library Media Education Program through International Exchange

    National Research Council Canada - National Science Library

    Houston, Cynthia

    2006-01-01

    .... Research on short-term international exchange programs indicates they contribute to the cognitive and personal growth prerequisite for developing a global perspective in both students and faculty...

  16. Development of Compact Heat Exchangers According to the Results Study of the Regularities of Heat Exchange Enhancement Energy Saving

    Science.gov (United States)

    Vasilev, V. Ya

    2017-11-01

    The conditions for the realization of energy-saving heat exchange enhancement are experimentally determined, in which the increase in heat transfer in the investigated surface ducts is equal to the growth of aerodynamic losses. A method for determining the geometric and regime parameters of surface ducts, which determine the energy-saving regimes of heat exchange enhancement, is implemented. Energy-saving enhancement of heat transfer in the interrupted ducts and channels with ridges and valleys allows, respectively, to 2.78 and 1.40 times to reduce the heat exchange surface and the mass of the heat exchanger with the previous energy costs. The results of the research make it possible to eliminate the intuitive choice of the shape and parameters of the ducts of the heat exchanger surfaces and to ensure their operation in energy-saving regimes.

  17. Contributions lexicographiques

    Directory of Open Access Journals (Sweden)

    France Bezlaj

    1955-12-01

    Full Text Available Dans les »Novice« du 6 avril 1859, p. 108, Fr. Pohorski (probablement un pseudonyme d'un auteur inconnu publia des matériaux lexicographiques sous le title »Quelques mots rares de Pohorje en Styrie«. Cette contribution passa inaperçue et Pleteršnik ne cite dans son dictionnaire que quelques-uns de ces mots qu'il a tirés d'une autre source. Dans un passé plus récent, J. Kelemina prit dans ce recueil le nom commun tega, teha »chalet de montagne«, die Taie en all. Carinth (Slovenski etnograf VI-VIII 323  *tegia, (prérom. Attegia (Meyer-Lübke, REW 761 et sot »chemin de montagne« (SR VIII 88, ce qui pourrait venir, après avoir passé par le roman, de (prérom.

  18. Enabling Detailed Energy Analyses via the Technology Performance Exchange: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Studer, D.; Fleming, K.; Lee, E.; Livingood, W.

    2014-08-01

    One of the key tenets to increasing adoption of energy efficiency solutions in the built environment is improving confidence in energy performance. Current industry practices make extensive use of predictive modeling, often via the use of sophisticated hourly or sub-hourly energy simulation programs, to account for site-specific parameters (e.g., climate zone, hours of operation, and space type) and arrive at a performance estimate. While such methods are highly precise, they invariably provide less than ideal accuracy due to a lack of high-quality, foundational energy performance input data. The Technology Performance Exchange was constructed to allow the transparent sharing of foundational, product-specific energy performance data, and leverages significant, external engineering efforts and a modular architecture to efficiently identify and codify the minimum information necessary to accurately predict product energy performance. This strongly-typed database resource represents a novel solution to a difficult and established problem. One of the most exciting benefits is the way in which the Technology Performance Exchange's application programming interface has been leveraged to integrate contributed foundational data into the Building Component Library. Via a series of scripts, data is automatically translated and parsed into the Building Component Library in a format that is immediately usable to the energy modeling community. This paper (1) presents a high-level overview of the project drivers and the structure of the Technology Performance Exchange; (2) offers a detailed examination of how technologies are incorporated and translated into powerful energy modeling code snippets; and (3) examines several benefits of this robust workflow.

  19. Forging Colloidal Nanostructures via Cation Exchange Reactions

    Science.gov (United States)

    2016-01-01

    Among the various postsynthesis treatments of colloidal nanocrystals that have been developed to date, transformations by cation exchange have recently emerged as an extremely versatile tool that has given access to a wide variety of materials and nanostructures. One notable example in this direction is represented by partial cation exchange, by which preformed nanocrystals can be either transformed to alloy nanocrystals or to various types of nanoheterostructures possessing core/shell, segmented, or striped architectures. In this review, we provide an up to date overview of the complex colloidal nanostructures that could be prepared so far by cation exchange. At the same time, the review gives an account of the fundamental thermodynamic and kinetic parameters governing these types of reactions, as they are currently understood, and outlines the main open issues and possible future developments in the field. PMID:26891471

  20. Performance Expectations of Closed-Brayton-Cycle Heat Exchangers in 100-kWe Nuclear Space Power Systems

    Science.gov (United States)

    Barrett, Michael J.

    2003-01-01

    Performance expectations of closed-Brayton-cycle heat exchangers to be used in 100-kWe nuclear space power systems were forecast. Proposed cycle state points for a system supporting a mission to three of Jupiter s moons required effectiveness values for the heat-source exchanger, recuperator and rejection exchanger (gas cooler) of 0.98,0.95 and 0.97, respectively. Performance parameters such as number of thermal units (Nm), equivalent thermal conductance (UA), and entropy generation numbers (Ns) varied from 11 to 19,23 to 39 kWK, and 0.019 to 0.023 for some standard heat exchanger configurations. Pressure-loss contributions to entropy generation were significant; the largest frictional contribution was 114% of the heat-transfer irreversibility. Using conventional recuperator designs, the 0.95 effectiveness proved difficult to achieve without exceeding other performance targets; a metallic, plate-fin counterflow solution called for 15% more mass and 33% higher pressure-loss than the target values. Two types of gas-coolers showed promise. Single-pass counterflow and multipass cross-counterflow arrangements both met the 0.97 effectiveness requirement. Potential reliability-related advantages of the cross-countefflow design were noted. Cycle modifications, enhanced heat transfer techniques and incorporation of advanced materials were suggested options to reduce system development risk. Carbon-carbon sheeting or foam proved an attractive option to improve overall performance.

  1. Mechanism of Ni2+ and NiOH+ interaction with hydroxamic acids in SDS: evaluation of the contributions to the equilibrium and rate parameters in the aqueous and micellar phase.

    Science.gov (United States)

    Beccia, Maria R; Biver, Tarita; García, Begoña; Leal, José M; Secco, Fernando; Ruiz, Rebeca; Venturini, Marcella

    2012-06-28

    The equilibria and kinetics (stopped-flow) of the binding of Ni(II) to salicylhydroxamic acid (SHA) and phenylbenzohydroxamic acid (PBHA) have been investigated in aqueous solutions containing SDS micelles. The two ligands are fairly distributed between the two pseudophases present, so the binding reaction occurs in both phases. The contributions to the total reaction from each phase has been evaluated, following a procedure where use is made of the experimentally determined partition coefficients of the reactants involved. The mechanism of the reaction occurring on the micelle surface has been derived and comparison with the mechanism in water shows that the step Ni(2+) + HL ⇄ NiHL(2+) is operative in both pseudophases, whereas the step Ni(2+) + L(-)⇄ NiL(+), which is operative in water, is replaced in SDS by the step NiOH(+) + HL ⇄ NiL(+). The analysis of the equilibrium and of the kinetic data enabled the evaluation of the equilibrium and the rate constants of the individual steps taking part in the binding process over the micelle surface. Interestingly, the first hydrolysis constant of the Ni(H(2)O)(6)(2+) ion in SDS is more than two orders of magnitude higher than in water. The agreement between the equilibrium constants derived from kinetics and those obtained by static measurements confirms the validity of the proposed mechanism.

  2. Exchanging Description Logic Knowledge Bases

    NARCIS (Netherlands)

    Arenas, M.; Botoeva, E.; Calvanese, D.; Ryzhikov, V.; Sherkhonov, E.

    2012-01-01

    In this paper, we study the problem of exchanging knowledge between a source and a target knowledge base (KB), connected through mappings. Differently from the traditional database exchange setting, which considers only the exchange of data, we are interested in exchanging implicit knowledge. As

  3. Regenerator heat exchanger – calculation of heat recovery efficiency and pressure loss

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per Kvols

    Performance of heat exchangers is determined based on two main parameters: efficiency to exchange / recover heat and pressure loss due to friction between fluid and exchanger surfaces. These two parameters are contradicting each other which mean that the higher is efficiency the higher becomes...... pressure loss. The aim of the optimized design of heat exchanger is to reach the highest or the required heat efficiency and at the same time to keep pressure losses as low as possible keeping total exchanger size within acceptable size. In this report is presented analytical calculation method...... to calculate efficiency and pressure loss in the regenerator heat exchanger with a fixed matrix that will be used in the decentralized ventilation unit combined in the roof window. Moreover, this study presents sensitivity study of regenerator heat exchanger performance, taking into account, such parameters as...

  4. Radiation effects on ion exchange materials

    Energy Technology Data Exchange (ETDEWEB)

    Gangwer, T.E.; Goldstein, M.; Pillay, K.K.S.

    1977-11-01

    An extensive literature review and data compilation has been completed on the radiation-damage of ion exchange resins. The primary goal of the study has been to review the available literature on ion exchange materials used in, as well as those with potential for use in, the nuclear fuel and waste reprocessing areas. The physical and chemical properties of ion exchangers are reviewed. Experimental parameters useful in characterizing the effects of radiation on synthetic ion exchange resins are identified or defined. In compiling the diverse types of data, an effort was made to present the experimental data or experimentally based parameters in a format that would be useful for inter-comparing radiation effects on resins. When subject to radiation there are various general trends or qualitative effects displayed by the different types of resins. These radiation-trends and effects have been formulated into qualitative statements. The present day level of understanding of the behavior of resins under ionizing radiation is too limited to justify quantitative predictive modeling. The limitations and deficiencies of the literature are discussed and the experimentation needed to achieve quantitative modeling are outlined. 14 figs., 108 references.

  5. Microgravity condensing heat exchanger

    Science.gov (United States)

    Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor); North, Andrew (Inventor); Weislogel, Mark M. (Inventor)

    2011-01-01

    A heat exchanger having a plurality of heat exchanging aluminum fins with hydrophilic condensing surfaces which are stacked and clamped between two cold plates. The cold plates are aligned radially along a plane extending through the axis of a cylindrical duct and hold the stacked and clamped portions of the heat exchanging fins along the axis of the cylindrical duct. The fins extend outwardly from the clamped portions along approximately radial planes. The spacing between fins is symmetric about the cold plates, and are somewhat more closely spaced as the angle they make with the cold plates approaches 90.degree.. Passageways extend through the fins between vertex spaces which provide capillary storage and communicate with passageways formed in the stacked and clamped portions of the fins, which communicate with water drains connected to a pump externally to the duct. Water with no entrained air is drawn from the capillary spaces.

  6. Ion exchange phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Bourg, I.C.; Sposito, G.

    2011-05-01

    Ion exchange phenomena involve the population of readily exchangeable ions, the subset of adsorbed solutes that balance the intrinsic surface charge and can be readily replaced by major background electrolyte ions (Sposito, 2008). These phenomena have occupied a central place in soil chemistry research since Way (1850) first showed that potassium uptake by soils resulted in the release of an equal quantity of moles of charge of calcium and magnesium. Ion exchange phenomena are now routinely modeled in studies of soil formation (White et al., 2005), soil reclamation (Kopittke et al., 2006), soil fertilitization (Agbenin and Yakubu, 2006), colloidal dispersion/flocculation (Charlet and Tournassat, 2005), the mechanics of argillaceous media (Gajo and Loret, 2007), aquitard pore water chemistry (Tournassat et al., 2008), and groundwater (Timms and Hendry, 2007; McNab et al., 2009) and contaminant hydrology (Chatterjee et al., 2008; van Oploo et al., 2008; Serrano et al., 2009).

  7. Thermal-Hydraulic Sensitivity Study of Intermediate Loop Parameters for Nuclear Hydrogen Production System

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jong Hwa; Lee, Heung Nae; Park, Jea Ho [KONES Corp., Seoul (Korea, Republic of); Lee, Won Jae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Sang Il; Yoo, Yeon Jae [Hyundai Engineering Co., Seoul (Korea, Republic of)

    2016-10-15

    The heat generated from the VHTR is transferred to the intermediate loop through Intermediate Heat Exchanger (IHX). It is further passed on to the Sulfur-Iodine (SI) hydrogen production system (HPS) through Process Heat Exchanger (PHX). The IL provides the safety distance between the VHTR and HPS. Since the IL performance affects the overall nuclear HPS efficiency, it is required to optimize its design and operation parameters. In this study, the thermal-hydraulic sensitivity of IL parameters with various coolant options has been examined by using MARS-GCR code, which was already applied for the case of steam generator. Sensitivity study of the IL and PHX parameters has been carried out based on their thermal-hydraulic performance. Several parameters for design and operation, such as the pipe diameter, safety distance and surface area, are considered for different coolant options, He, CO{sub 2} and He-CO{sub 2} (2:8). It was found that the circulator work is the major factor affecting on the overall nuclear hydrogen production system efficiency. Circulator work increases with the safety distance, and decreases with the operation pressure and loop pipe diameter. Sensitivity results obtained from this study will contribute to the optimization of the IL design and operation parameters and the optimal coolant selection.

  8. Diversidade de Gênero e Formação do Endogrupo: uma contribuição da teoria da troca entre líder e membro (LMXDiversity of Gender and Formation of Ingroup: a contribution of leader-member exchange theory – LMXDiversidad de Género y Formacion de Endogrupo: una contribuición de la leader-member exchange theory - LMX

    Directory of Open Access Journals (Sweden)

    SILVA, Adilson Aderito da

    2007-05-01

    Full Text Available RESUMOO objetivo do presente artigo é investigar a relação existente entre os pressupostos da Teoria da Troca entre Líder e Membro – LMX e a diversidade de gênero. Para tanto, foi utilizado um questionário denominado LMX-MDM, desenvolvido por Liden e Maslyn (1998. O instrumento é composto de 11 assertivas que mensuram a multidimensionalidade da LMX. O questionário passou pelo processo de tradução reversa e foi aplicado a uma amostra de estudantes da Universidade Presbiteriana Mackenzie, localizada na cidade de São Paulo. A amostra foi composta de 241 alunos sendo que 124 (51,5% são homens e 117 (48,5% são mulheres. Os dados obtidos foram submetidos às técnicas uni e multivariadas, e os resultados revelaram que, na amostra pesquisada, os sujeitos percebem as dimensões afeto, lealdade, contribuição e respeito profissional conforme os pressupostos da LMX e que as pessoas do gênero feminino sentem-se mais participantes do endogrupo do que as pessoas do gênero masculino.ABSTRACTThe purpose of this article is to investigate the relationship between the Leader and Member Exchange Theory – LMX´s assumptions and the diversity of genders. To accomplish it, a questionnaire named LMX-MDM developed by Liden and Maslyn (1998 was used. The instrument is composed by 11 propositions that measures the multidimensionality of LMX. The questionnaire was submitted to a reversed translation process and was applied on a sample of students from Universidade Presbiteriana Mackenzie, located in São Paulo. The sample was composed of 241 students, from which 124 (51,5% men and 117 (48,5% women. The collected data was submitted to univariate and multivariate techniques, and the results revealed that the researched sample perceives the dimensions of affection, loyalty, contribution and professional respect in line with LMX´s assumptions, and that female gender feel more participant of the ingroup than people from the ale group.RESUMENEl objetivo del

  9. Heat exchanger panel

    Science.gov (United States)

    Warburton, Robert E. (Inventor); Cuva, William J. (Inventor)

    2005-01-01

    The present invention relates to a heat exchanger panel which has broad utility in high temperature environments. The heat exchanger panel has a first panel, a second panel, and at least one fluid containment device positioned intermediate the first and second panels. At least one of the first panel and the second panel have at least one feature on an interior surface to accommodate the at least one fluid containment device. In a preferred embodiment, each of the first and second panels is formed from a high conductivity, high temperature composite material. Also, in a preferred embodiment, the first and second panels are joined together by one or more composite fasteners.

  10. Microscale Regenerative Heat Exchanger

    Science.gov (United States)

    Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred

    2006-01-01

    The device described herein is designed primarily for use as a regenerative heat exchanger in a miniature Stirling engine or Stirling-cycle heat pump. A regenerative heat exchanger (sometimes called, simply, a "regenerator" in the Stirling-engine art) is basically a thermal capacitor: Its role in the Stirling cycle is to alternately accept heat from, then deliver heat to, an oscillating flow of a working fluid between compression and expansion volumes, without introducing an excessive pressure drop. These volumes are at different temperatures, and conduction of heat between these volumes is undesirable because it reduces the energy-conversion efficiency of the Stirling cycle.

  11. Symmetry in social exchange and health

    Science.gov (United States)

    Siegrist, Johannes

    2005-10-01

    Symmetry is a relevant concept in sociological theories of exchange. It is rooted in the evolutionary old norm of social reciprocity and is particularly important in social contracts. Symmetry breaking through violation of the norm of reciprocity generates strain in micro-social systems and, above all, in victims of non-symmetric exchange. In this contribution, adverse healthconsequences of symmetry breaking in contractual social exchange are analysed, with a main focus on the employment contract. Scientific evidence is derived from prospective epidemiological studies testing the model of effort-reward imbalance at work. Overall, a twofold elevated risk of incident disease is observed in employed men and women who are exposed to non-symmetric exchange. Health risks include coronary heart disease, depression and alcohol dependence, among others. Preliminary results suggest similar effects on health produced by symmetry breaking in other types of social relationships (e.g. partnership, parental roles). These findings underline the importance of symmetry in contractual social exchange for health and well-being.

  12. Electronic device for measuring the polarization parameter in the {pi}{sup -}p {yields} {pi}{sup 0}n charge exchange reaction on a polarized proton target; Un appareillage electronique destine a la mesure du parametre de polarisation dans la reaction d'echange de charge {pi}{sup -}p {yields} {pi}{sup 0}n sur cible de protons polarises

    Energy Technology Data Exchange (ETDEWEB)

    Brehin, S. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-12-15

    An electronic apparatus has been constructed to measure the polarization parameter P{sub 0}(t) in {pi}{sup -}p {yields} {pi}{sup 0}n charge exchange scattering at 5.9 GeV/c and 11,2 GeV/c on polarized proton target. This device insures triggering of a heavy plate spark chamber, allowing visualisation of {gamma} rays from the {pi}{sup 0} decays when the associated neutron offers suitable characteristics in direction and energy. The neutron is detected by an array of 32 counters and his energy is measured by a time of flight method. Electronic circuits of this apparatus are described as test and calibration methods used. (author) [French] Un appareillage electronique a ete realise pour mesurer le parametre de polarisation P{sub 0}(t) dans la reaction d'echange de charge {pi}{sup -}p {yields} {pi}{sup 0}n a 5,9 GeV/c et 11,2 GeV/c sur une cible de protons polarises. Ce dispositif assure le declenchement d'une chambre a etincelles a plaques lourdes, permettant de visualiser les {gamma} de desitegration du {pi}{sup 0}, lorsque le neutron associe presente les caracteristiques convenables en direction et en energie. Le neutron est detecte par un ensemble de 32 compteurs et son energie est mesuree par une methode de temps de vol. Les circuits composant cet appareillage sont decrits ainsi que les methodes d'etalonnage et de verification utilisees. (auteur)

  13. Contribution to the determination of the neutronic parameters uncertainties of a compact heterogeneous core: the material testing Jules Horowitz reactor; Contribution a l'etude des incertitudes des parametres neutroniques d'un coeur compact et heterogene: le reacteur d'irradiation Jules Horowitz

    Energy Technology Data Exchange (ETDEWEB)

    Di Salvo, J

    2002-07-01

    The design studies of the future Material Testing Reactor Jules Horowitz require the development of an adapted neutronic calculation route. To guarantee good accuracy and save time cost, some approximations with deterministic modelling (APOLLO2 / CRONOS2) are needed. As no relevant integral experiments are yet available to ensure the accuracy of the calculation, the results need to be validated by a rigorous methodical approach, which is based on comparison against numerical benchmarks (Monte Carlo TRIPOLI4 code). In order to complete the validation results, sensitivity coefficients of main neutronic parameters to nuclear data are very useful to get an estimate of the final uncertainty on the calculation. Unfortunately, most of covariance information is missing in the recent evaluated files such as JEF-2.2. To generate missing covariance matrices, a method based on the comparison of different independent evaluations is used in this study. Special attention is paid to the determination of sensitivity coefficients, using perturbation methods and direct calculations. This study points out the importance of the non-diagonal elements of the covariance matrices as well as the neutron capture cross section uncertainty of the 27Al in the thermal range. In complement to uncertainty studies, it will be still necessary to obtain integral experimental validation of the Jules Horowitz Reactor neutronic parameters calculations. (author)

  14. Nature's Heat Exchangers.

    Science.gov (United States)

    Barnes, George

    1991-01-01

    Discusses the heat-transfer systems of different animals. Systems include heat conduction into the ground, heat transferred by convection, heat exchange in lizards, fish and polar animals, the carotid rete system, electromagnetic radiation from animals and people, and plant and animal fiber optics. (MDH)

  15. Basic Exchange Rate Theories

    NARCIS (Netherlands)

    J.G.M. van Marrewijk (Charles)

    2005-01-01

    textabstractThis four-chapter overview of basic exchange rate theories discusses (i) the elasticity and absorption approach, (ii) the (long-run) implications of the monetary approach, (iii) the short-run effects of monetary and fiscal policy under various economic conditions, and (iv) the transition

  16. Technology Performance Exchange

    Energy Technology Data Exchange (ETDEWEB)

    2015-09-01

    To address the need for accessible, high-quality data, the Department of Energy has developed the Technology Performance Exchange (TPEx). TPEx enables technology suppliers, third-party testing laboratories, and other entities to share product performance data. These data are automatically transformed into a format that technology evaluators can easily use in their energy modeling assessments to inform procurement decisions.

  17. Telephone Exchange Maintenance

    CERN Document Server

    2005-01-01

    Urgent maintenance work on CERN telephone exchanges will be performed on 24 March from 6 a.m. to 8 a.m. Telephone services may be disrupted or even interrupted during this time. For more details, please contact us by email at Standard.Telephone@cern.ch.

  18. Baltic Exchange toodi Tallinna

    Index Scriptorium Estoniae

    2007-01-01

    Viimane osa merekonteineritesse kokkupakitud Londoni laevandus- ja merebörsi Baltic Exchange'i endise peakorteri detailidest jõudis 2007. a. juunis Tallinna. Hoone detailid ostnud ärimehed Heiti Hääl ja Eerik-Niiles Kross plaanivad leida hoonele koha Tallinna kesklinnas. E.-N. Krossi kommentaar

  19. Heat exchanger. Varmeveksler

    Energy Technology Data Exchange (ETDEWEB)

    Rosman, I.E.; Wagner, W.R.

    1986-03-17

    The invention concerns a manifold for a plate-type heat exchanger, and includes a side channel connected the inlet of the manifold. The plates can be designed as an integral assembly together with the integrated side- and external end-manifolds as well. 16 drawings.

  20. Chemical exchange program analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Waffelaert, Pascale

    2007-09-01

    As part of its EMS, Sandia performs an annual environmental aspects/impacts analysis. The purpose of this analysis is to identify the environmental aspects associated with Sandia's activities, products, and services and the potential environmental impacts associated with those aspects. Division and environmental programs established objectives and targets based on the environmental aspects associated with their operations. In 2007 the most significant aspect identified was Hazardous Materials (Use and Storage). The objective for Hazardous Materials (Use and Storage) was to improve chemical handling, storage, and on-site movement of hazardous materials. One of the targets supporting this objective was to develop an effective chemical exchange program, making a business case for it in FY07, and fully implementing a comprehensive chemical exchange program in FY08. A Chemical Exchange Program (CEP) team was formed to implement this target. The team consists of representatives from the Chemical Information System (CIS), Pollution Prevention (P2), the HWMF, Procurement and the Environmental Management System (EMS). The CEP Team performed benchmarking and conducted a life-cycle analysis of the current management of chemicals at SNL/NM and compared it to Chemical Exchange alternatives. Those alternatives are as follows: (1) Revive the 'Virtual' Chemical Exchange Program; (2) Re-implement a 'Physical' Chemical Exchange Program using a Chemical Information System; and (3) Transition to a Chemical Management Services System. The analysis and benchmarking study shows that the present management of chemicals at SNL/NM is significantly disjointed and a life-cycle or 'Cradle-to-Grave' approach to chemical management is needed. This approach must consider the purchasing and maintenance costs as well as the cost of ultimate disposal of the chemicals and materials. A chemical exchange is needed as a mechanism to re-apply chemicals on site. This

  1. Exchange Rate Deregulation and Industrial Performance: An ...

    African Journals Online (AJOL)

    FIRST LADY

    CIPG = βo + β1EXR + β2INTR + β3TOT + µ2............. (iii). Where IPGR is industrial productivity growth rate and it is calculated as;. IPGR = (IOt-1 – IOt)/IOt-1. IO is index of industrial output. CIPG is contribution of industrial production to GDP, calculated as;. CIPG = (IO/GDP) X 100/1. Exchange Rate Deregulation and Industrial ...

  2. Counterflow Regolith Heat Exchanger

    Science.gov (United States)

    Zubrin, Robert; Jonscher, Peter

    2013-01-01

    A problem exists in reducing the total heating power required to extract oxygen from lunar regolith. All such processes require heating a great deal of soil, and the heat energy is wasted if it cannot be recycled from processed material back into new material. The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat exchanger with internal and external augers attached to the inner rotating tube to move the regolith. Hot regolith in the outer tube is moved in one direction by a right-hand - ed auger, and the cool regolith in the inner tube is moved in the opposite direction by a left-handed auger attached to the inside of the rotating tube. In this counterflow arrangement, a large fraction of the heat from the expended regolith is transferred to the new regolith. The spent regolith leaves the heat exchanger close to the temperature of the cold new regolith, and the new regolith is pre-heated close to the initial temperature of the spent regolith. Using the CoRHE can reduce the heating requirement of a lunar ISRU system by 80%, reducing the total power consumption by a factor of two. The unique feature of this system is that it allows for counterflow heat exchange to occur between solids, instead of liquids or gases, as is commonly done. In addition, in variants of this concept, the hydrogen reduction can be made to occur within the counterflow heat exchanger itself, enabling a simplified lunar ISRU (in situ resource utilization) system with excellent energy economy and continuous nonbatch mode operation.

  3. Analytical applications of ion exchangers

    CERN Document Server

    Inczédy, J

    1966-01-01

    Analytical Applications of Ion Exchangers presents the laboratory use of ion-exchange resins. This book discusses the development in the analytical application of ion exchangers. Organized into 10 chapters, this book begins with an overview of the history and significance of ion exchangers for technical purposes. This text then describes the properties of ion exchangers, which are large molecular water-insoluble polyelectrolytes having a cross-linked structure that contains ionic groups. Other chapters consider the theories concerning the operation of ion-exchange resins and investigate th

  4. 77 FR 4070 - Self-Regulatory Organizations; C2 Options Exchange, Incorporated; Notice of Filing and Immediate...

    Science.gov (United States)

    2012-01-26

    ... Exchange may determine to apply these price check parameters to market orders and/or marketable limit... price check parameters that apply to both market orders and marketable limit complex orders.\\5\\ In... future, should the Exchange would determine to apply this price check parameter feature to ratio orders...

  5. DHE (downhole heat exchangers). [Downhole Heat Exchangers (DHE)

    Energy Technology Data Exchange (ETDEWEB)

    Culver, G.

    1990-11-01

    The use of downhole heat exchangers (DHE) for residential or commercial space and domestic water heating and other applications has several desirable features. Systems are nearly or completely passive -- that is, no or very little geothermal water or steam is produced from the well either reducing or completely eliminating surface environmental concerns and the need for disposal systems or injection wells. Initial cost of pumps and installation are eliminated or reduced along with pumping power costs and maintenance costs associated with pumping often corrosive geothermal fluids. Many residential and small commercial systems do not require circulating pumps because the density difference in the incoming and outgoing sides of the loop are sufficient to overcome circulating friction losses in the entire system. The major disadvantage of DHEs is their dependence on natural heat flow. In areas where geological conditions provide high permeability and a natural hydraulic gradient, DHEs can provide a substantial quantity of heat. A single 500-ft (152 m) well in Klamath Falls, Oregon, supplies over one megawatt thermal and output is apparently limited by the surface area of pipe that can be installed in the well bore. In contrast, DHEs used in conjunction with heat pumps may supply less than 8 KW from a well of similar depth. Here output is limited by conductive heat flow with perhaps a small contribution from convection near the well bore. The highest capacity DHE reported to date, in Turkey, supplies 6 MW thermal from an 820-ft (250 m) well. There were two main goals for this project. The first was to gather, disseminate and exchange internationally information on DHES. The second was to perform experiments that would provide insight into well bore/aquifer interaction and thereby provide more information on which to base DHE designs. 27 refs., 31 figs., 3 tabs.

  6. Data Exchange Inventory (DEXI) System

    Data.gov (United States)

    Social Security Administration — DEXI is an intranet application used by SSA users to track all incoming and outgoing data exchanges between SSA and our data exchange partners. Information such as...

  7. Hubungan Antara Parameter Model Dan Parameter Peramalan

    OpenAIRE

    Siregar, Salamat

    2011-01-01

    Studies on the relationship between model parameters and forecasting parameter is an urgent and important study carried out in order to obtain some certainty about how exactly the effect of one parameter model for others of other model parameters and forecast parameters. To make the discussion of the issue, selected cases of weather forecasting (weather forecasting) as a model case to study the relationship between model parameters and weather forecasting. The model used was the Numerical Wea...

  8. Fabrication of Nd-Fe-B exchange-spring magnets

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen Mau Lam [Department of Physics, Pedagogic University of Hanoi No 2, Xuan Hoa, Phuc Yen, Vinh Phuc (Viet Nam); Nguyen Thi Thanh Huyen [University of Industry, Dong Trieu, Quang Ninh (Viet Nam); Do Hung Manh; Vu Hong Ky; Do Khanh Tung; Nguyen Huy Dan [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi (Viet Nam)], E-mail: dannh@ims.vast.ac.vn

    2009-09-01

    In this report we present our recent results on fabrication of Nd-Fe-B exchange-spring magnets using melt-spinning method. Additive elements were used to improve useful parameters of this kind of hard magnetic materials. Hot pressing technique was applied to increase mass density of the magnets. The compositions and technology routes for fabricating the Nd-Fe-B exchange-spring magnets with maximum energy product (BH){sub max} above 10 MGOe were shown.

  9. A novel technique for highly accurate gas exchange measurements

    Science.gov (United States)

    Kalkenings, R. K.; Jähne, B. J.

    2003-04-01

    cameras. In this contribution the dependence of gas exchange on a number of parameters such as the mean square slope will be presented.

  10. Dynamical Clustering of Exchange Rates

    OpenAIRE

    Fenn, Daniel J.; Porter, Mason A.; Mucha, Peter J; Mark McDonald; Stacy Williams; Johnson, Neil F.; Jones, Nick S

    2009-01-01

    We use techniques from network science to study correlations in the foreign exchange (FX) market over the period 1991--2008. We consider an FX market network in which each node represents an exchange rate and each weighted edge represents a time-dependent correlation between the rates. To provide insights into the clustering of the exchange rate time series, we investigate dynamic communities in the network. We show that there is a relationship between an exchange rate's functional role withi...

  11. Lipid exchange by ultracentrifugation

    DEFF Research Database (Denmark)

    Drachmann, Nikolaj Düring; Olesen, Claus

    2014-01-01

    Lipids play an important role in maintaining P-type ATPase structure and function, and often they are crucial for ATPase activity. When the P-type ATPases are in the membrane, they are surrounded by a mix of different lipids species with varying aliphatic chain lengths and saturation......, and the complex interplay between the lipids and the P-type ATPases are still not well understood. We here describe a robust method to exchange the majority of the lipids surrounding the ATPase after solubilisation and/or purification with a target lipid of interest. The method is based on an ultracentrifugation...... step, where the protein sample is spun through a dense buffer containing large excess of the target lipid, which results in an approximately 80-85 % lipid exchange. The method is a very gently technique that maintains protein folding during the process, hence allowing further characterization...

  12. Exchange rate rebounds after foreign exchange market interventions

    Science.gov (United States)

    Hoshikawa, Takeshi

    2017-03-01

    This study examined the rebounds in the exchange rate after foreign exchange intervention. When intervention is strongly effective, the exchange rate rebounds at next day. The effect of intervention is reduced slightly by the rebound after the intervention. The exchange rate might have been 67.12-77.47 yen to a US dollar without yen-selling/dollar-purchasing intervention of 74,691,100 million yen implemented by the Japanese government since 1991, in comparison to the actual exchange rate was 103.19 yen to the US dollar at the end of March 2014.

  13. CYLINDER OF THE DISPOSABLE MASS EXCHANGE DEVICE FOR HEMOSORPTION

    Directory of Open Access Journals (Sweden)

    F. I. Kazakov

    2015-01-01

    Full Text Available BACKGROUND. Hemocarboperfusion, previously widely used in our country, can universally pass out of use due to the lack of industrial production of disposable mass exchange devices.MATERIAl AND METHODS. Physicochemical properties of materials and design features of the body samples elements of various sizes have been studied.RESULTS. The elements and materials properties of the hemosorption mass exchanger cylinder have been studied. Hydrodynamic parameters of manipulation using the developed cylinders at different perfusion rates have been studied in bench experiments.CONCLUSION. The original cylinder of the disposable mass exchange device for hemosorption, which meets the current clinical needs, has been developed. 

  14. The stability of exchange networks

    NARCIS (Netherlands)

    Doğan, G.; Assen, M. van; Rijt, A. van de; Buskens, V.W.

    2009-01-01

    Economic and sociological exchange theories predict divisions of exchange benefits given an assumed fixed network of exchange relations. Since network structure has been found to have a large impact on actors’ payoffs, actors have strong incentives for network change.Weanswer the question what

  15. Integrated foreign exchange risk management

    DEFF Research Database (Denmark)

    Aabo, Tom; Høg, Esben; Kuhn, Jochen

    2010-01-01

    Empirical research has focused on export as a proxy for exchange rate exposure and the use of foreign exchange derivatives as an instrument to deal with this exposure. This empirical study applies an integrated foreign exchange risk management approach with a particular focus on the role of impor...

  16. Integrated Foreign Exchange Risk Management

    DEFF Research Database (Denmark)

    Aabo, Tom; Høg, Esben; Kuhn, Jochen

    Empirical research has focused on export as a proxy for the exchange rate exposure and the use of foreign exchange derivatives as the instrument to deal with this exposure. This empirical study applies an integrated foreign exchange risk management approach with a particular focus on the role...

  17. Scraped surface heat exchangers.

    Science.gov (United States)

    Rao, Chetan S; Hartel, Richard W

    2006-01-01

    Scraped surface heat exchangers (SSHEs) are commonly used in the food, chemical, and pharmaceutical industries for heat transfer, crystallization, and other continuous processes. They are ideally suited for products that are viscous, sticky, that contain particulate matter, or that need some degree of crystallization. Since these characteristics describe a vast majority of processed foods, SSHEs are especially suited for pumpable food products. During operation, the product is brought in contact with a heat transfer surface that is rapidly and continuously scraped, thereby exposing the surface to the passage of untreated product. In addition to maintaining high and uniform heat exchange, the scraper blades also provide simultaneous mixing and agitation. Heat exchange for sticky and viscous foods such as heavy salad dressings, margarine, chocolate, peanut butter, fondant, ice cream, and shortenings is possible only by using SSHEs. High heat transfer coefficients are achieved because the boundary layer is continuously replaced by fresh material. Moreover, the product is in contact with the heating surface for only a few seconds and high temperature gradients can be used without the danger of causing undesirable reactions. SSHEs are versatile in the use of heat transfer medium and the various unit operations that can be carried out simultaneously. This article critically reviews the current understanding of the operations and applications of SSHEs.

  18. Timing Foreign Exchange Markets

    Directory of Open Access Journals (Sweden)

    Samuel W. Malone

    2016-03-01

    Full Text Available To improve short-horizon exchange rate forecasts, we employ foreign exchange market risk factors as fundamentals, and Bayesian treed Gaussian process (BTGP models to handle non-linear, time-varying relationships between these fundamentals and exchange rates. Forecasts from the BTGP model conditional on the carry and dollar factors dominate random walk forecasts on accuracy and economic criteria in the Meese-Rogoff setting. Superior market timing ability for large moves, more than directional accuracy, drives the BTGP’s success. We explain how, through a model averaging Monte Carlo scheme, the BTGP is able to simultaneously exploit smoothness and rough breaks in between-variable dynamics. Either feature in isolation is unable to consistently outperform benchmarks throughout the full span of time in our forecasting exercises. Trading strategies based on ex ante BTGP forecasts deliver the highest out-of-sample risk-adjusted returns for the median currency, as well as for both predictable, traded risk factors.

  19. Paste heat exchange

    Energy Technology Data Exchange (ETDEWEB)

    1943-07-30

    The subject of coal paste heat exchangers is discussed in this letter report from Gelsenberg A.G. to I.G. Farbenindustrie A.G. Gelsenberg had given little consideration to the heating of coal paste by means of regeneration (heat exchange) because of the lack of experience in paste regeneration with bituminous coal, especially at 700 atmospheres. At the I.G. Farben plant at Poelitz, paste regeneration was carried out so that low concentration coal paste was heated in the regenerator together with the process gas, and the remaining coal was fed into the cold pass of the preheater in a thicker paste. Later tests proved this process viable. Gelsenberg heated normal coal paste and the gas in heat exchangers with the goal of relieving the preheater. Good results were achieved without change in design. The coal paste was heated with process gas in the regenerator at up to 315 degrees with constant pressure difference, so that after three months no decrease in K-values and no deposition or thickening was observed. Through the omission of paste gas, the pressure difference of the system became more constant and did not rise above the former level. The temperature also was more controllable, the chamber smoother running. Principal thermal data are given in a table. 1 table, 1 graph.

  20. The exchangeability of shape

    Directory of Open Access Journals (Sweden)

    Kaba Dramane

    2010-10-01

    Full Text Available Abstract Background Landmark based geometric morphometrics (GM allows the quantitative comparison of organismal shapes. When applied to systematics, it is able to score shape changes which often are undetectable by traditional morphological studies and even by classical morphometric approaches. It has thus become a fast and low cost candidate to identify cryptic species. Due to inherent mathematical properties, shape variables derived from one set of coordinates cannot be compared with shape variables derived from another set. Raw coordinates which produce these shape variables could be used for data exchange, however they contain measurement error. The latter may represent a significant obstacle when the objective is to distinguish very similar species. Results We show here that a single user derived dataset produces much less classification error than a multiple one. The question then becomes how to circumvent the lack of exchangeability of shape variables while preserving a single user dataset. A solution to this question could lead to the creation of a relatively fast and inexpensive systematic tool adapted for the recognition of cryptic species. Conclusions To preserve both exchangeability of shape and a single user derived dataset, our suggestion is to create a free access bank of reference images from which one can produce raw coordinates and use them for comparison with external specimens. Thus, we propose an alternative geometric descriptive system that separates 2-D data gathering and analyzes.

  1. Effect of size sprinkled heat exchange surface on developing boiling

    Directory of Open Access Journals (Sweden)

    Petr Kracík

    2016-06-01

    Full Text Available This article presents research of sprinkled heat exchangers. This type of research has become rather topical in relation to sea water desalination. This process uses sprinkling of exchangers which rapidly separates vapour phase from a liquid phase. Applications help better utilize low-potential heat which is commonly wasted in utility systems. Low-potential heat may increase utilization of primary materials. Our ambition is to analyse and describe the whole sprinkled exchanger. Two heat exchangers were tested with a similar tube pitch: heat exchanger no. 1 had a four-tube bundle and heat exchanger no. 2 had eight-tube bundle. Efforts were made to maintain similar physical characteristics. They were tested at two flow rates (ca 0.07 and 0.11 kg s−1 m−1 and progress of boiling on the bundle was observed. Initial pressure was ca 10 kPa (abs at which no liquid was boiling at any part of the exchanger; the pressure was then lowered. Other input parameters were roughly similar for both flow rates. Temperature of heating water was ca 50°C at a constant flow rate of ca 7.2 L min−1. Results of our experiments provide optimum parameters for the given conditions for both tube bundles.

  2. Review of SR-Can: Evaluation of SKB's handling of spent fuel performance, radionuclide chemistry and geosphere transport parameters. External review contribution in support of SKI's and SSI's review of SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    Stenhouse, Mike (Monitor Scientific LLC, Denver, CO (US)); Jegou, Christophe (Commissariat a l' Energie Atomique (CEA) (FR)); Brown, Paul (Geochem Australia (AU)); Meinrath, Guenther (RER Consultants, Passau (DE)); Nitsche, Heino (Univ. of California, Berkeley (US)); Ekberg, Christian (Chalmers University of Technology (SE))

    2008-03-15

    SR-Can covers the containment phase of the KBS-3 barriers as well as the consequences of releases of radionuclides to the rock and eventually the biosphere (after complete containment within fuel canisters has partially failed). The aim of this report is to provide a range of review comments with respect to those parameters related to spent fuel performance as well as radionuclide chemistry and transport. These parameter values are used in the quantification of consequences due to release of radionuclides from potentially leaking canisters. The report does not cover modelling approaches used for quantification of consequences. However, modelling used to derive parameter values is to some extent addressed (such as calculation of maximum radionuclide concentration due to formation of solubility limiting phases). The following are the key highlights and comments generated in the course of the review: Inconsistencies exist between recommendations provided in technical reports and those quoted in the Data Report. One of the reasons for such inconsistencies has been the timing of different pieces of research. It is hoped that the timing of contributions to SR-Site will be such that these inconsistencies can be avoided. Sensitivity analyses need to be carried out and reported in a number of areas to support some of the assumptions or decisions made in the assessment calculations. The likelihood is that SKB has performed many of the sensitivity analyses identified in different parts of this report, but these need to be reported, preferably to complement the recommendations provided

  3. The impact of exchange rate volatility on emerging market exports

    Directory of Open Access Journals (Sweden)

    Johannes Khosa

    2015-02-01

    Full Text Available Orientation: High exchange rate volatility has implications for business and policy decisions and exchange rate movements are important in debates around trade and trade policies. Research purpose: The purpose of the research was to determine the impact of exchange rate volatility on exports in emerging markets. Motivation for the study: A lack of clarity in literature regarding this relationship increases the risk of improper planning by export organisations as well as implementing suboptimal economic policies. Research design, approach and method: This research analysed the effect of exchange rate volatility on emerging market exports using a sample of nine emerging countries from 1995 to 2010. Panel data analysis was conducted. Volatility was measured by Generalised Autoregressive Conditional Heteroscedasticity and conventional standard deviation in order to determine if the instrument of volatility used influenced the nature of the relationship between exchange rate volatility and exports. The Pedroni residual cointegration method was used to test for panel cointegration in order to determine if there was a long-run relationship. Main findings: The results showed that exchange rate volatility had a significant negative effect on the performance of exports, regardless of the measure of volatility used. It was also evident that a long-run relationship did exist. Practical/managerial implications: The study concluded that the policy mix that will reduce exchange rate volatility (such as managed exchange rate regimes and relatively competitive exchange rates were essential for emerging markets in order to sustain their exports performance. Contribution/value-add: This research provided policy makers of emerging market economies with new evidence pertaining to the relationship between exchange rate volatility and the performance of exports. This research contributed to the existing knowledge on the topic and provides a base for future

  4. Optimal sampling schedule for chemical exchange saturation transfer.

    Science.gov (United States)

    Tee, Y K; Khrapitchev, A A; Sibson, N R; Payne, S J; Chappell, M A

    2013-11-01

    The sampling schedule for chemical exchange saturation transfer imaging is normally uniformly distributed across the saturation frequency offsets. When this kind of evenly distributed sampling schedule is used to quantify the chemical exchange saturation transfer effect using model-based analysis, some of the collected data are minimally informative to the parameters of interest. For example, changes in labile proton exchange rate and concentration mainly affect the magnetization near the resonance frequency of the labile pool. In this study, an optimal sampling schedule was designed for a more accurate quantification of amine proton exchange rate and concentration, and water center frequency shift based on an algorithm previously applied to magnetization transfer and arterial spin labeling. The resulting optimal sampling schedule samples repeatedly around the resonance frequency of the amine pool and also near to the water resonance to maximize the information present within the data for quantitative model-based analysis. Simulation and experimental results on tissue-like phantoms showed that greater accuracy and precision (>30% and >46%, respectively, for some cases) were achieved in the parameters of interest when using optimal sampling schedule compared with evenly distributed sampling schedule. Hence, the proposed optimal sampling schedule could replace evenly distributed sampling schedule in chemical exchange saturation transfer imaging to improve the quantification of the chemical exchange saturation transfer effect and parameter estimation. Copyright © 2013 Wiley Periodicals, Inc.

  5. Treasury Bond Market Segment at Bucharest Stock Exchange

    Directory of Open Access Journals (Sweden)

    Georgescu Maria Andrada

    2013-04-01

    Full Text Available The present paper aims to present the level of development reached by Romanian Treasury bond market segment at Bucharest Stock Exchange. A trial will be made to identify the determinants that contributed to the current level of development of domestic secondary government bond market and the factors that can generate a further (and improved development. The analysis will be descriptive (the data series available for Romanian are short, based on the secondary data offered by Bucharest Stock Exchange.

  6. Ligand Exchange Kinetics of Environmentally Relevant Metals

    Energy Technology Data Exchange (ETDEWEB)

    Panasci, Adele Frances [Univ. of California, Davis, CA (United States)

    2014-07-15

    The interactions of ground water with minerals and contaminants are of broad interest for geochemists but are not well understood. Experiments on the molecular scale can determine reaction parameters (i.e. rates of ligand exchange, activation entropy, activation entropy, and activation volume) that can be used in computations to gain insight into reactions that occur in natural groundwaters. Experiments to determine the rate of isotopic ligand exchange for three environmentally relevant metals, rhodium (Rh), iron (Fe), and neptunium (Np), are described. Many environmental transformations of metals (e.g. reduction) in soil occur at trivalent centers, Fe(III) in particular. Contaminant ions absorb to mineral surfaces via ligand exchange, and the reversal of this reaction can be dangerous, releasing contaminants into the environment. Ferric iron is difficult to study spectroscopically because most of its complexes are paramagnetic and are generally reactive toward ligand exchange; therefore, Rh(III), which is diamagnetic and less reactive, was used to study substitution reactions that are analogous to those that occur on mineral oxide surfaces. Studies on both Np(V) and Np(VI) are important in their own right, as 237Np is a radioactive transuranic element with a half-life of 2 million years.

  7. Complex use of heat-exchange tunnels

    Directory of Open Access Journals (Sweden)

    А. Ф. Галкин

    2017-04-01

    Full Text Available The paper presents separate results of complex research (experimental and theoretical on the application of heat-exchange tunnels – in frozen rocks, among other things – as underground constructions serving two purposes. It is proposed to use heat-exchange tunnels as a separate multi-functional module, which under normal conditions will be used to set standards of heat regime parameters in the mines, and in emergency situations, natural or man-made, will serve as a protective structure to shelter mine workers. Heat-exchange modules can be made from mined-out or specially constructed tunnels. Economic analysis shows that the use of such multi-functional modules does not increase operation and maintenance costs, but enhances safety of mining operations and reliability in case of emergency situations. There are numerous theoretic and experimental investigations in the field of complex use of mining tunnels, which allows to develop regulatory design documents on their basis. Experience of practical application of heat-exchange tunnels has been assessed from the position of regulating heat regime in the mines.

  8. Kinetic study of heavy metal ions removal by ion exchange in batch conical air spouted bed

    Directory of Open Access Journals (Sweden)

    T.M. Zewail

    2015-03-01

    Full Text Available Spouted bed contactor is a hybrid of fixed and fluidized bed contactors, which retains the advantages of each with good hydrodynamic conditions. The aim of the present study is to investigate the performance of a batch conical air spouted vessel for heavy metal removal by strong cation exchange resins (AMBERJET 1200 Na. The effect of various parameters such as type of heavy metal ions (Ni+2 and Pb+2, contact time, superficial air velocity and initial heavy metal ion concentration on % heavy metal ion removal has been investigated. It has been found that under optimum conditions 98% and 99% removal of Ni+2 and Pb+2 were achieved respectively. Several kinetic models were used to test the experimental data and to examine the controlling mechanism of the sorption process. The present results of Ni+2 and Pb+2 well fit pseudo second order kinetic model with a high correlation coefficient. Both film diffusion and intra-particle diffusion contribute to the ion exchange process. The present study revealed that spouted bed vessel may provide an effective alternative for conducting ion exchange reactions.

  9. Molecular Exchange in Ordered Diblock Copolymer Micelles

    Science.gov (United States)

    Choi, Soo-Hyung; Lodge, Timothy; Bates, Frank

    2011-03-01

    Previously, molecular exchange between spherical micelles in dilute solution (1 vol% polymer) was investigated using time-resolved small-angle neutron scattering (TR-SANS). As the concentration of spherical micelles formed by the diblock copolymers increases, the micelles begin to overlap and eventually pack onto body-centered cubic (BCC) lattice. In this study, concentrated, ordered micelles (15 vol% polymers) prepared by dispersing isotopically labeled poly(styrene- b -ethylene-alt-propylene) in an isotopic squalane mixture was investigated to understand the micellar concentration dependence of the molecular exchange. Perfectly random mixing of isotopically labeled micelles on the BCC lattice was confirmed by SANS patterns where the interparticle contribution vanishes, resulting in an intensity that directly relates to the exchange kinetics. The measured molecular exchange process for the concentrated, ordered system is qualitatively consistent with the previous observations, but the rate is more than an order of magnitude slower than that for the dilute, disordered system. Infineum(IPrime), MRSEC(NSF), NIST.

  10. Optimization of porous microchannel heat exchanger

    Science.gov (United States)

    Kozhukhov, N. N.; Konovalov, D. A.

    2017-11-01

    The technical progress in information and communication sphere leads to a sharp increase in the use of radio electronic devices. Functioning of radio electronics is accompanied by release of thermal energy, which must be diverted from the heat-stressed element. Moreover, using of electronics at negative temperatures, on the contrary, requires supply of a certain amount of heat to start the system. There arises the task of creating a system that allows both to supply and to divert the necessary amount of thermal energy. The development of complex thermostabilization systems for radio electronic equipment is due to increasing the efficiency of each of its elements separately. For more efficient operation of a heat exchanger, which directly affects the temperature of the heat-stressed element, it is necessary to calculate the mode characteristics and to take into account the effect of its design parameters. The results of optimizing the microchannel heat exchanger are presented in the article. The target optimization functions are the mass, pressure drop and temperature. The parameters of optimization are the layout of porous fins, their geometric dimensions and coolant flow. For the given conditions, the optimum variant of porous microchannel heat exchanger is selected.

  11. Renormalizable two-parameter piecewise isometries.

    Science.gov (United States)

    Lowenstein, J H; Vivaldi, F

    2016-06-01

    We exhibit two distinct renormalization scenarios for two-parameter piecewise isometries, based on 2π/5 rotations of a rhombus and parameter-dependent translations. Both scenarios rely on the recently established renormalizability of a one-parameter triangle map, which takes place if and only if the parameter belongs to the algebraic number field K=Q(5) associated with the rotation matrix. With two parameters, features emerge which have no counterpart in the single-parameter model. In the first scenario, we show that renormalizability is no longer rigid: whereas one of the two parameters is restricted to K, the second parameter can vary continuously over a real interval without destroying self-similarity. The mechanism involves neighbouring atoms which recombine after traversing distinct return paths. We show that this phenomenon also occurs in the simpler context of Rauzy-Veech renormalization of interval exchange transformations, here regarded as parametric piecewise isometries on a real interval. We explore this analogy in some detail. In the second scenario, which involves two-parameter deformations of a three-parameter rhombus map, we exhibit a weak form of rigidity. The phase space splits into several (non-convex) invariant components, on each of which the renormalization still has a free parameter. However, the foliations of the different components are transversal in parameter space; as a result, simultaneous self-similarity of the component maps requires that both of the original parameters belong to the field K.

  12. Cation exchange properties of zeolites in hyper alkaline aqueous media.

    Science.gov (United States)

    Van Tendeloo, Leen; de Blochouse, Benny; Dom, Dirk; Vancluysen, Jacqueline; Snellings, Ruben; Martens, Johan A; Kirschhock, Christine E A; Maes, André; Breynaert, Eric

    2015-02-03

    Construction of multibarrier concrete based waste disposal sites and management of alkaline mine drainage water requires cation exchangers combining excellent sorption properties with a high stability and predictable performance in hyper alkaline media. Though highly selective organic cation exchange resins have been developed for most pollutants, they can serve as a growth medium for bacterial proliferation, impairing their long-term stability and introducing unpredictable parameters into the evolution of the system. Zeolites represent a family of inorganic cation exchangers, which naturally occur in hyper alkaline conditions and cannot serve as an electron donor or carbon source for microbial proliferation. Despite their successful application as industrial cation exchangers under near neutral conditions, their performance in hyper alkaline, saline water remains highly undocumented. Using Cs(+) as a benchmark element, this study aims to assess the long-term cation exchange performance of zeolites in concrete derived aqueous solutions. Comparison of their exchange properties in alkaline media with data obtained in near neutral solutions demonstrated that the cation exchange selectivity remains unaffected by the increased hydroxyl concentration; the cation exchange capacity did however show an unexpected increase in hyper alkaline media.

  13. Precise Determination of the Z Resonance Parameters at LEP Zedometry

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Bailey, I.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Benelli, G.; Bentvelsen, S.; Beeston, C.; Bethke, S.; Biebel, O.; Bloodworth, I.J.; Boeriu, O.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Cammin, J.; Capiluppi, P.; Carnegie, R.K.; Caron, B.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couchman, J.; Coxe, R.L.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Dallison, S.; Darling, C.; De Roeck, A.; De Wolf, E.A.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Fanti, M.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Foucher, M.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gascon, J.; Gascon-Shotkin, S.M.; Gary, J.W.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giacomelli, R.; Glenzinski, D.; Goldberg, J.; Grandi, C.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Hajdu, C.; Hanson, G.G.; Harder, K.; Harel, A.; Harin-Dirac, M.; Hart, P.A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hillier, S.J.; Hocker, James Andrew; Hoffman, Kara Dion; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Kirk, J.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Krop, D.; Kuhl, T.; Kupper, M.; Kyberd, P.; Lafferty, G.D.; Lahmann, R.; Lai, W.P.; Landsman, H.; Lanske, D.; Lauber, J.; Lawson, I; Layter, J.G.; Lee, A.M.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; Lillich, J.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Marchant, T.E.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Menges, W.; Menke, S.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Montanari, A.; Mori, T.; Muller, U.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Oh, A.; Okpara, A.; Oldershaw, N.J.; Oreglia, M.J.; Orito, S.; Palmonari, F.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Przybycien, M.; Quadt, A.; Quast, G.; Rabbertz, K.; Raith, B.; Rembser, C.; Renkel, P.; Rick, H.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schmitt, B.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Skuja, A.; Smith, A.M.; Smith, T.J.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Springer, Robert Wayne; Sproston, M.; Stahl, A.; Stephens, K.; Stoll, K.; Strom, David M.; Strohmer, R.; Stumpf, L.; Surrow, B.; Talbot, S.D.; Tarem, S.; Taylor, R.J.; Teuscher, R.; Tecchio, M.; Thomas, J.; Thomson, M.A.; Towers, S.; Toya, D.; Trefzger, T.; Trigger, I.; Trocsanyi, Z.; Tsukamoto, T.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Vachon, B.; Vannerem, P.; Verzocchi, M.; Vokurka, E.H.; Voss, H.; Vossebeld, J.; Wagner, A.; Wagner, D.L.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Zacek, V.; Zer-Zion, D.

    2001-01-01

    This final analysis of hadronic and leptonic cross-sections and of leptonic forward-backward asymmetries in e+e- collisions with the OPAL detector makes use of the full LEP1 data sample comprising 161 pb^-1 of integrated luminosity and 4.5 x 10^6 selected Z decays. An interpretation of the data in terms of contributions from pure Z exchange and from Z-gamma interference allows the parameters of the Z resonance to be determined in a model-independent way. Our results are in good agreement with lepton universality and consistent with the vector and axial-vector couplings predicted in the Standard Model. A fit to the complete dataset yields the fundamental Z resonance parameters: mZ = 91.1852 +- 0.0030 GeV, GZ = 2.4948 +- 0.0041 GeV, s0h = 41.501 +- 0.055 nb, Rl = 20.823 +- 0.044, and Afb0l = 0.0145 +- 0.0017. Transforming these parameters gives a measurement of the ratio between the decay width into invisible particles and the width to a single species of charged lepton, Ginv/Gl = 5.942 +- 0.027. Attributing th...

  14. The Dynamics of Multilateral Exchange

    Science.gov (United States)

    Hausken, Kjell; Moxnes, John F.

    The article formulates a dynamic mathematical model where arbitrarily many players produce, consume, exchange, loan, and deposit arbitrarily many goods over time to maximize utility. Consuming goods constitutes a benefit, and producing, exporting, and loaning away goods constitute a cost. Utilities are benefits minus costs, which depend on the exchange ratios and bargaining functions. Three-way exchange occurs when one player acquires, through exchange, one good from another player with the sole purpose of using this good to exchange against the desired good from a third player. Such a triple handshake is not merely a set of double handshakes since the player assigns no interest to the first good in his benefit function. Cognitive and organization costs increase dramatically for higher order exchanges. An exchange theory accounting for media of exchange follows from simple generalization of two-way exchange. The examples of r-way exchange are the triangle trade between Africa, the USA, and England in the 17th and 18th centuries, the hypothetical hypercycle involving RNAs as players and enzymes as goods, and reaction-diffusion processes. The emergence of exchange, and the role of trading agents are discussed. We simulate an example where two-way exchange gives zero production and zero utility, while three-way exchange causes considerable production and positive utility. Maximum utility for each player is reached when exchanges of the same order as the number of players in society are allowed. The article merges micro theory and macro theory within the social, natural, and physical sciences.

  15. Cryogenic regenerative heat exchangers

    CERN Document Server

    Ackermann, Robert A

    1997-01-01

    An in-depth survey of regenerative heat exchangers, this book chronicles the development and recent commercialization of regenerative devices for cryogenic applications. Chapters cover historical background, concepts, practical applications, design data, and numerical solutions, providing the latest information for engineers to develop advanced cryogenic machines. The discussions include insights into the operation of a regenerator; descriptions of the cyclic and fluid temperature distributions in a regenerator; data for various matrix geometries and materials, including coarse and fine bronze, stainless steel-woven wire mesh screens, and lead spheres; and unique operating features of cryocoolers that produce deviations from ideal regenerator theory.

  16. Exporter Price Response to Exchange Rate Changes

    DEFF Research Database (Denmark)

    Fosse, Henrik Barslund

    Firms exporting to foreign markets face a particular challenge: to price their exports in a foreign market when the exchange rate changes. This paper takes on pricing- to-market using a unique data set that covers rm level monthly trade at great detail. As opposed to annual trade ows, monthly trade...... theoretical contributions to the litterature on pricing-to-market and exchange rate pass-through....... ows bring us closer to the transaction level where rm decisions are actually made. I nd that the utilization of monthly data does add new information about the average level of pricing-to-market, and the di¤erences between long-run pricing-to-market and short-run pricing-to-market. Furthermore, I nd...

  17. Spatio-Temporal Data Exchange Standards

    DEFF Research Database (Denmark)

    Jensen, Christian Søndergaard; Schmidt, Albrecht

    2003-01-01

    We believe that research that concerns aspects of spatio-temporal data management may benefit from taking into account the various standards for spatio-temporal data formats. For example, this may contribute to rendering prototype software “open” and more readily useful. This paper thus identifies...... and briefly surveys standardization in relation to primarily the exchange and integration of spatio-temporal data. An overview of several data exchange languages is offered, along with reviews their potential for facilitating the collection of test data and the leveraging of prototypes. The standards, most...... of which are XML-based, lend themselves to the integration of prototypes into middleware architectures, e.g., as Web services....

  18. Katabatic Wind-Driven Exchange in Fjords

    Science.gov (United States)

    Spall, Michael A.; Jackson, Rebecca H.; Straneo, Fiammetta

    2017-10-01

    The general issue of katabatic wind-driven exchange in fjords is considered using an idealized numerical model, theory, and observations. Two regimes are identified. For fjords narrower than a viscous boundary layer width, the exchange is limited by a balance between wind and friction in lateral boundary layers. For the nonlinear viscous parameterization used here, this boundary layer thickness depends on the properties of the fjord, such as stratification and length, as well as on the wind stress and numerical parameters such as grid spacing and an empirical constant. For wider fjords typical of east Greenland, the balance is primarily between wind, the along-fjord pressure gradient, and acceleration, in general agreement with previous two-layer nonrotating theories. It is expected that O(10%) of the surface layer will be flushed out of the fjord by a single wind event. Application of the idealized model to a typical katabatic wind event produces outflowing velocities that are in general agreement with observations in Sermilik Fjord, a large glacial fjord in southeast Greenland. The presence of a sill has only a minor influence on the exchange until the sill penetrates over most of the lower layer thickness, in which cases the exchange is reduced. It is concluded that the multiple katabatic wind events per winter that are experienced by the fjords along east Greenland represent an important mechanism of exchange between the fjord and shelf, with implications for the renewal of warm, salty waters at depth and for the export of glacial freshwater in the upper layer.

  19. Level density parameter in relativistic models

    Energy Technology Data Exchange (ETDEWEB)

    Centelles, M. (Dept. d' Estructura i Constituents de la Materia, Facultat de Fisica, Univ. de Barcelona (Spain)); Vinas, X. (Dept. d' Estructura i Constituents de la Materia, Facultat de Fisica, Univ. de Barcelona (Spain)); Schuck, P. (Inst. des Sciences Nucleaires, 38 Grenoble (France))

    1994-01-24

    The level density parameter for finite nuclei is studied in the framework of the relativistic mean field theory. Systematic self-consistent calculations are performed in the Thomas-Fermi approximation using [sigma]-[omega] models that include scalar meson self-couplings. For realistic nuclear matter properties, the level density parameter turns out to be in the range of values obtained in non-relativistic calculations with Skyrme interactions, and thus it is smaller than the global trend of the experimental data. The implications for the level density parameter of including vacuum fluctuations and exchange corrections in the mean field theory are also investigated. (orig.)

  20. Developing bulk exchange spring magnets

    Energy Technology Data Exchange (ETDEWEB)

    Mccall, Scott K.; Kuntz, Joshua D.

    2017-06-27

    A method of making a bulk exchange spring magnet by providing a magnetically soft material, providing a hard magnetic material, and producing a composite of said magnetically soft material and said hard magnetic material to make the bulk exchange spring magnet. The step of producing a composite of magnetically soft material and hard magnetic material is accomplished by electrophoretic deposition of the magnetically soft material and the hard magnetic material to make the bulk exchange spring magnet.

  1. Characteristics of model heat exchanger

    Science.gov (United States)

    Kolínský, Jan

    2017-09-01

    The aim of this paper is thermal analysis of model water to water heat exchanger at different mass flow rates. Experimental study deals with determination of total heat transfer - power of the heat exchanger. Furthermore the paper deals with analysis of heat exchanger charakcteristic using a definition of thermal efficiency. It is demonstrated that it is advisable to monitor the dependence of thermal efficiency and flow ratio.

  2. What Drives Stock Exchange Integration?

    National Research Council Canada - National Science Library

    Ekaterina Dorodnykh

    2013-01-01

    .... After a broad discussion of the existent literature, the investigation combines a large number of potentially relevant determinants for the explanation of whether stock exchanges are participating...

  3. Mastering Microsoft Exchange Server 2013

    CERN Document Server

    Elfassy, David

    2013-01-01

    The bestselling guide to Exchange Server, fully updated for the newest version Microsoft Exchange Server 2013 is touted as a solution for lowering the total cost of ownership, whether deployed on-premises or in the cloud. Like the earlier editions, this comprehensive guide covers every aspect of installing, configuring, and managing this multifaceted collaboration system. It offers Windows systems administrators and consultants a complete tutorial and reference, ideal for anyone installing Exchange Server for the first time or those migrating from an earlier Exchange Server version.Microsoft

  4. Research on Heat Exchange Process in Aircraft Air Conditioning System

    Science.gov (United States)

    Chichindaev, A. V.

    2017-11-01

    Using of heat-exchanger-condenser in the air conditioning system of the airplane Tu-204 (Boeing, Airbus, Superjet 100, MS-21, etc.) for cooling the compressed air by the cold air with negative temperature exiting the turbine results in a number of operational problems. Mainly it’s frosting of the heat exchange surface, which is the cause of live-section channels frosting, resistance increasing and airflow in the system decreasing. The purpose of this work is to analyse the known freeze-up-fighting methods for heat-exchanger-condenser, description of the features of anti-icing protection and offering solutions to this problem. For the problem of optimizing the design of heat exchangers in this work used generalized criterion that describes the ratio of thermal resistances of cold and hot sections, which include: the ratio of the initial values of heat transfer agents flow state; heat exchange surface finning coefficients; factors which describes the ratio of operating parameters and finning area. By controlling the ratio of the thermal resistances can be obtained the desired temperature of the heat exchange surface, which would prevent freezing. The work presents the results of a numerical study of the effect of different combinations of regime and geometrical factors changes on reduction of the heat-exchanger-condenser freezing surface area, including using of variable ratio of thermal resistances.

  5. Optimized heat exchanger unit in a thermoacoustic refrigerator

    Science.gov (United States)

    El-Fawal, Mawahib Hassan; Mohd-Ghazali, Normah

    2012-06-01

    Due to concern over the environmental impact caused by hazardous refrigerants, the last ten years or so has seen increasing research into thermoacoustic refrigeration. A thermoacoustic refrigerator is a device which uses acoustic power to pump heat. It holds the merits of simple mechanical design, absence of harmful refrigerants and having no or few moving parts. However, the performance of the thermoacoustic refrigerator, particularly the standing wave types, is currently not competitive compared to its counterpart conventional vapor-compression refrigerator. Thermoacoustic refrigeration prototypes, built up-to-date, achieved 0.1-0.2 relative coefficient of performance (COPR) compared with that of 0.33-0.5 for the conventional vapor-compression refrigerators. The poor heat exchanger design is one of the reasons for this poor efficiency. This paper discussed the influence of the thermoacoustic refrigerator heat exchanger's parameters on its design and the optimization of the performance of the system using the Lagrange multiplier method. The results showed that, the dissipated power is less than the published value by about 49% in the cold heat exchanger and about 38.5% in the hot heat exchanger. Furthermore, the increase of the cold heat exchanger effectiveness is found to be 3%. Thus, the decrease in the dissipated power in both heat exchangers with effective cold heat exchanger increases the performance of the thermoacoustic refrigerator.

  6. Hybrid Heat Exchangers

    Science.gov (United States)

    Tu, Jianping Gene; Shih, Wei

    2010-01-01

    A hybrid light-weight heat exchanger concept has been developed that uses high-conductivity carbon-carbon (C-C) composites as the heat-transfer fins and uses conventional high-temperature metals, such as Inconel, nickel, and titanium as the parting sheets to meet leakage and structural requirements. In order to maximize thermal conductivity, the majority of carbon fiber is aligned in the fin direction resulting in 300 W/m.K or higher conductivity in the fin directions. As a result of this fiber orientation, the coefficient of thermal expansion (CTE) of the C-C composite in both non-fiber directions matches well with the CTE of various high-temperature metal alloys. This allows the joining of fins and parting sheets by using high-temperature braze alloys.

  7. Analysis of data for hypercharge-exchange reactions

    CERN Document Server

    Irving, A C; Martin, A D

    1973-01-01

    The properties of the experimental data on the hypercharge- exchange reactions pi N to K Sigma , K Lambda and KN to pi Sigma , pi Lambda in the region (4/16)GeV/c are surveyed, with attention to line-reversal inequalities, reaction energy dependences in terms of effective trajectories, phase-energy properties, and SU/sub 3/ for exchanges. The s-channel helicity nonflip amplitudes at 4 and 14 GeV/c are determined, assuming an exchange degenerate K/sub V/*-K/sub T/* Regge- pole approximation for the flip amplitudes. In the impact-parameter representation only the imaginary parts of the pi N to KY nonflip amplitudes (or in terms of exchanges Im K/sub V/*) are found to be peripheral. All other nonflip amplitude components are central. An SU /sub 3/ comparison is made with K/sup -/p to eta Lambda , eta ' Lambda data. (28 refs).

  8. Hydraulic Validation of the LHC Cold Mass Heat Exchanger Tube

    CERN Document Server

    Provenaz, P

    1998-01-01

    The knowledge of the helium mass flow vs. the fraction of the tube wetted by the liquid helium II in the heat exchanger is a crucial input parameter for the heat exchange since the heat flux is direct ly proportional to the wetted surface. In the range of liquid and gas velocities inside the heat exchanger, the liquid flow behaves like in an open channel. Looking at the flow equations for such a s ituation, the velocity depends on the fluid properties only by the friction factor which is a function of the Reynolds number. Thus it was decided to build an experiment with water in order to check t he open channel equations in the heat exchanger geometry. This paper shows the results for water and gives the extrapolation for helium.

  9. Heat exchanger optimization for geothermal district heating systems: A fuel saving approach

    Energy Technology Data Exchange (ETDEWEB)

    Dagdas, Ahmet [Department of Mechanical Engineering, Yildiz Technical University, 34349 Besiktas, Istanbul (Turkey)

    2007-05-15

    One of the most commonly used heating devices in geothermal systems is the heat exchanger. The output conditions of heat exchangers are based on several parameters. The heat transfer area is one of the most important parameters for heat exchangers in terms of economics. Although there are a lot of methods to optimize heat exchangers, the method described here is a fairly easy approach. In this paper, a counter flow heat exchanger of geothermal district heating system is considered and optimum design values, which provide maximum annual net profit, for the considered heating system are found according to fuel savings. Performance of the heat exchanger is also calculated. In the analysis, since some values are affected by local conditions, Turkey's conditions are considered. (author)

  10. Methodological approach for evaluating the geo-exchange potential: VIGOR Project

    Directory of Open Access Journals (Sweden)

    Antonio Galgaro

    2012-12-01

    Full Text Available In the framework of VIGOR Project, a national project coordinated by the Institute of Geosciences and Earth Resources (CNR-IGG and sponsored by the Ministry of Economic Development (MiSE, dedicated to the evaluation of geothermal potential in the regions of the Convergence Objective in Italy (Puglia, Calabria, Campania and Sicily, is expected to evaluate the ability of the territory to heat exchange with the ground for air conditioning of buildings. To identify the conditions for the development of low enthalpy geothermal systems collected and organized on a regional scale geological and stratigraphic data useful for the preparation of a specific thematic mapping, able to represent in a synergistic and simplified way the physical parameters (geological, lithostratigraphic, hydrogeological, thermodynamic that most influence the subsoil behavior for thermal exchange. The litho-stratigraphic and hydrogeological database created for every region led to the production of different cartographic thematic maps, such as the thermal conductivity (lithological and stratigraphical, the surface geothermal flux, the average annual temperature of air, the climate zoning, the areas of hydrogeological restrictions. To obtain a single representation of the geo-exchange potential of the region, the different thematic maps described must be combined together by means of an algorithm, defined on the basis of the SINTACS methodology. The purpose is to weigh the contributions of the involved parameters and to produce a preliminary synthesis map able to identify the territorial use of geothermal heat pump systems, based on the geological characteristics and in agreement with the existing regulatory constraints.

  11. Reversal magnetization, spin reorientation, and exchange bias in YCr O3 doped with praseodymium

    Science.gov (United States)

    Durán, A.; Escamilla, R.; Escudero, R.; Morales, F.; Verdín, E.

    2018-01-01

    Crystal structure, thermal properties, and magnetic properties were studied systematically in Y1 -xP rxCr O3 with 0.0 ≤x ≤0.3 compositions. Magnetic susceptibility and specific-heat measurements show an increase in the antiferromagnetic transition temperature (TN) as Pr is substituted in the Y sites and notable magnetic features are observed below TN. Strong coupling between magnetic and crystalline parameters is observed in a small range of Pr compositions. A small perturbation in the lattice parameters by a Pr ion is sufficient to induce a spin-reorientation transition followed by magnetization reversal to finally induce the exchange-bias effect. The spin-reorientation temperature (TSR) is increased from 35 to 149 K for 0.025 ≤x ≤0.1 compositions. It is found that the Cr spin sublattice rotates continuously from TSR to a new spin configuration at lower temperature. In addition, magnetization reversal is observed at T*˜35 K for x =0.05 up to T*˜63 K for x =0.20 composition. The M -H curves show a negative exchange-bias effect induced by Pr ions, which are observed below 100 K and are more intense at 5 K. At 10 K, the magnetic contribution of the specific heat as well as the ZFC magnetization show the rise of a peak with increasing Pr content. The magnetic anomaly could be associated with the freezing of the Pr magnetic moment randomly distributed at the 4 c crystallographic site. A clear correspondence between spin reorientation, magnetization reversal, and exchange-bias anisotropy with the tilting and octahedral distortion is also discussed.

  12. Induced ferro-ferromagnetic exchange bias in nanocrystalline systems

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-García, J.C.; Rivas, M.; García, J.A.

    2015-03-01

    An unusual magnetic hysteresis consisting of horizontally shifted and distorted loops appears in some Co-based nanocrystalline systems in which soft and hard ferromagnetic phases coexist. The bias field can be tuned at room temperature by premagnetising treatments. Several works attributed the origin of this effect to the dipolar interaction, while little attention has been paid to the exchange interaction contribution due to its short-range nature. In this paper the relative importance of the dipolar and exchange interactions is investigated by means of micromagnetic simulations. It is demonstrated that the exchange coupling, though a nearest-neighbour interaction, has far-reaching repercussions in the magnetic configuration, and substantially prevails over the magnetostatic interaction as the cause of the asymmetrical magnetisation reversal. The straightforward conclusion is that we are dealing with a ferro-ferromagnetic exchange bias effect. - Highlights: • Magnetic biphase nanocrystalline systems with biased hysteresis loops are presented. • Computational calculations including magnetostatic and exchange interactions have been made. • Exchange interaction largely prevails as the cause of the biasing effect. • The biasing of HL is due to exchange coupling of both ferromagnetic phases. • Assuming monodomain behaviour for the crystals allows simulating the experimental HL.

  13. Effects of interest and exchange rate policies on Brazilian exports

    Directory of Open Access Journals (Sweden)

    Cláudia Maria Sonaglio

    2016-01-01

    Full Text Available In heterodox literature, the industrial sector is considered strategic for economic development. Consequently, reducing the contribution of this sector in the production of the country before it has reached the stage of economic maturity, affects the productive dynamics and slow technical progress. The appreciation of the real exchange rate is seen as one of the factors responsible for the reduction of the external competitiveness of Brazilian manufactures, and this exchange rate valuation may be occurring due to the differences between domestic and international interest rates. Given this context, the aim of this study is to evaluate the impact of changes in the monetary and exchange rate policy and in the composition of the total exports on the performance of the Brazilian economy using a structuralist model. The results reinforce the importance of the manufacturing sector to economic growth, especially in a competitive exchange rate environment.

  14. Emulsion ripening through molecular exchange at droplet contacts.

    Science.gov (United States)

    Roger, Kevin; Olsson, Ulf; Schweins, Ralf; Cabane, Bernard

    2015-01-26

    Two coarsening mechanisms of emulsions are well established: droplet coalescence (fusion of two droplets) and Ostwald ripening (molecular exchange through the continuous phase). Here a third mechanism is identified, contact ripening, which operates through molecular exchange upon droplets collisions. A contrast manipulated small-angle neutron scattering experiment was performed to isolate contact ripening from coalescence and Ostwald ripening. A kinetic study was conducted, using dynamic light scattering and monodisperse nanoemulsions, to obtain the exchange key parameters. Decreasing the concentration or adding ionic repulsions between droplets hinders contact ripening by decreasing the collision frequency. Using long surfactant chains and well-hydrated heads inhibits contact ripening by hindering fluctuations in the film. Contact ripening can be controlled by these parameters, which is essential for both emulsion formulation and delivery of hydrophobic ingredients. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Simulating Replica Exchange: Markov State Models, Proposal Schemes, and the Infinite Swapping Limit.

    Science.gov (United States)

    Zhang, Bin W; Dai, Wei; Gallicchio, Emilio; He, Peng; Xia, Junchao; Tan, Zhiqiang; Levy, Ronald M

    2016-08-25

    Replica exchange molecular dynamics is a multicanonical simulation technique commonly used to enhance the sampling of solvated biomolecules on rugged free energy landscapes. While replica exchange is relatively easy to implement, there are many unanswered questions about how to use this technique most efficiently, especially because it is frequently the case in practice that replica exchange simulations are not fully converged. A replica exchange cycle consists of a series of molecular dynamics steps of a set of replicas moving under different Hamiltonians or at different thermodynamic states followed by one or more replica exchange attempts to swap replicas among the different states. How the replica exchange cycle is constructed affects how rapidly the system equilibrates. We have constructed a Markov state model of replica exchange (MSMRE) using long molecular dynamics simulations of a host-guest binding system as an example, in order to study how different implementations of the replica exchange cycle can affect the sampling efficiency. We analyze how the number of replica exchange attempts per cycle, the number of MD steps per cycle, and the interaction between the two parameters affects the largest implied time scale of the MSMRE simulation. The infinite swapping limit is an important concept in replica exchange. We show how to estimate the infinite swapping limit from the diagonal elements of the exchange transition matrix constructed from MSMRE "simulations of simulations" as well as from relatively short runs of the actual replica exchange simulations.

  16. 78 FR 69910 - Joint Industry Plan; BATS Exchange, Inc., BATS-Y Exchange, Inc., BOX Options Exchange LLC, C2...

    Science.gov (United States)

    2013-11-21

    ... COMMISSION Joint Industry Plan; BATS Exchange, Inc., BATS-Y Exchange, Inc., BOX Options Exchange LLC, C2... LLC, NYSE Arca, Inc. and Topaz Exchange, LLC; Notice of Filing of Proposed National Market System Plan... and Exchange Commission (``Commission'') the proposed National Market System (``NMS'') Plan Governing...

  17. Thermal analysis of shell and tube heat exchangers using artificial ...

    African Journals Online (AJOL)

    A feed-forward artificial neural network is set up to simplify the iterative nature of the design process. This also gives the necessary quick design iteration cycles to reach the optimized design. A design space is created with heat exchanger parameters, and the feed forward network is trained with semi-empirical data.

  18. Assessing the identifiability in isotope exchange depth profiling measurements

    DEFF Research Database (Denmark)

    Ciucci, Francesco; Panagakos, Grigorios; Chen, Chi

    2014-01-01

    Accurate identification of the physical parameters describing the surface exchange kinetic coefficient k and oxygen diffusion coefficient D is key in solid state ionics, because the performance of many ionic devices is connected to such quantities. In this work we extend and generalize the concept...

  19. Biogeochemistry of Phosphorus Exchange in Magnetic Bacteria

    Science.gov (United States)

    Drennen, C.; Popa, R.; Nealson, K.

    2005-12-01

    Magnetotactic bacteria swim (some at high relative speeds of ~5 mm/min) across the sediment water interface, in both freshwater and marine ecosystems, this occurs in an apparent diurnal pattern. We hypothesized that this is part of a migratory life cycle across the oxic anoxic transition zone (OATZ), at the water-sediment interface. Magnetotactic bacteria have been shown to contain sizable reserves of metals, phosphorus and sulfur. If the migration model is true, then this migration has important consequences on the exchange of phosphorous, sulfur and metals between water and sediments. Our results show that the exchange of phosphorus between magnetic bacteria and water is consistent with a periodic life cycle. These results also show that magnetic cells accumulate large amounts of phosphate under oxidizing conditions. Under reducing and anaerobic conditions (e.g. sulfidic, low Eh sediments) cells release phosphorus. This research shows the importance of magnetic bacteria in the exchange of materials across redox interfaces. Magnetotactic bacteria may also play a significant role in biomineralization and bioweathering of metal oxides and phosphates, as well as possibly contributing to the magnetization of sediments.

  20. Liquid/liquid heat exchanger

    Science.gov (United States)

    Miller, C. G.

    1980-01-01

    Conceptual design for heat exchanger, utilizing two immiscible liquids with dissimilar specific gravities in direct contact, is more efficient mechanism of heat transfer than conventional heat exchangers with walls or membranes. Concept could be adapted for collection of heat from solar or geothermal sources.

  1. Educators Exchange: A Program Evaluation.

    Science.gov (United States)

    Armstrong, William B.

    The Educators Exchange Program (EEP) was established under a training and educational exchange agreement reached by California's San Diego Community College District (SDCCD) and the republic of Mexico. In the program, the District provided a 4-week technological training program to faculty at Centros de Capacitacion Tecnologica Industrial…

  2. Risk Balance in Exchange Protocols

    NARCIS (Netherlands)

    M.T. Dashti (Mohammad); Y. Wang (Yanjing); I. Cervesato

    2007-01-01

    htmlabstractWe study the behaviour of rational agents in exchange protocols which rely on trustees. We allow malicious parties to compromise the trustee by paying a cost and, thereby, present a game analysis that advocates exchange protocols which induce balanced risks on the participants. We also

  3. Professional Exchange: Mapping the Future.

    Science.gov (United States)

    Dingman, Robert L.

    1993-01-01

    New associate editor of Professional Exchange section of "Journal of Mental Health Counseling" discusses importance of section. Lists potential topics suggested in 1989, then adds several other topics to the list. Concludes with guidelines for submission to Professional Exchange section. (NB)

  4. Pengaruh Leader Member Exchange Terhadap Kinerja Karyawan Di Hotel X Surabaya

    OpenAIRE

    Hutama, Patrick; Goenawan, Rocky

    2017-01-01

    Leader Member Exchange merupakan kualitas hubungan timbal Balik antara pemimpin dan karyawan dalam sebuah organisasi. Dalam penelitian ini menggunakan Leader Member Exchange sebagai variabel yang memiliki 4 dimensi, yaitu affect, loyalty, contribution, dan professional respect. Penelitian ini bertujuan untuk mengetahui hubungan dari Leader Member Exchange dan kinerja karyawan di Hotel X Surabaya. Dengan sampel yang melibatkan 35 karyawan, hasil penelitian menunjukkan bahwa Leader Member Excha...

  5. Heat exchanger leakage problem location

    Directory of Open Access Journals (Sweden)

    Jícha Miroslav

    2012-04-01

    Full Text Available Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.

  6. Transendothelial lipoprotein exchange and microalbuminuria

    DEFF Research Database (Denmark)

    Jensen, Jan Skov; Feldt-Rasmussen, Bo; Jensen, Kurt Svarre

    2004-01-01

    OBJECTIVE: Microalbuminuria associates with increased risk of atherosclerosis in individuals without diabetes. We hypothesized that transendothelial lipoprotein exchange is elevated among such individuals, possibly explaining increased intimal lipoprotein accumulation and thus atherosclerosis....... METHODS: Using an in vivo isotope technique, transendothelial exchange of low density lipoprotein (LDL) was measured in 77 non-diabetic individuals. Autologous 131-iodinated LDL was reinjected intravenously, and the 1-h fractional escape rate was calculated as index of transendothelial exchange. RESULTS......: There was no difference in transendothelial LDL exchange between subjects with microalbuminuria versus normoalbuminuria (mean (95% confidence interval) 3.8%/h (3.3-4.3%/h) versus 4.2%/h (3.7-4.7%/h); P=0.33). In contrast, there was a positive correlation between transendothelial LDL exchange and (logarithmically...

  7. Next Generation Microchannel Heat Exchangers

    CERN Document Server

    Ohadi, Michael; Dessiatoun, Serguei; Cetegen, Edvin

    2013-01-01

    In Next Generation Microchannel Heat Exchangers, the authors’ focus on the new generation highly efficient heat exchangers and presentation of novel data and technical expertise not available in the open literature.  Next generation micro channels offer record high heat transfer coefficients with pressure drops much less than conventional micro channel heat exchangers. These inherent features promise fast penetration into many mew markets, including high heat flux cooling of electronics, waste heat recovery and energy efficiency enhancement applications, alternative energy systems, as well as applications in mass exchangers and chemical reactor systems. The combination of up to the minute research findings and technical know-how make this book very timely as the search for high performance heat and mass exchangers that can cut costs in materials consumption intensifies.

  8. High Temperature Heat Exchanger Project

    Energy Technology Data Exchange (ETDEWEB)

    Anthony E. Hechanova, Ph.D.

    2008-09-30

    The UNLV Research Foundation assembled a research consortium for high temperature heat exchanger design and materials compatibility and performance comprised of university and private industry partners under the auspices of the US DOE-NE Nuclear Hydrogen Initiative in October 2003. The objectives of the consortium were to conduct investigations of candidate materials for high temperature heat exchanger componets in hydrogen production processes and design and perform prototypical testing of heat exchangers. The initial research of the consortium focused on the intermediate heat exchanger (located between the nuclear reactor and hydrogen production plan) and the components for the hydrogen iodine decomposition process and sulfuric acid decomposition process. These heat exchanger components were deemed the most challenging from a materials performance and compatibility perspective

  9. Patient Protection and Affordable Care Act; exchange and insurance market standards for 2015 and beyond. Final rule.

    Science.gov (United States)

    2014-05-27

    This final rule addresses various requirements applicable to health insurance issuers, Affordable Insurance Exchanges (``Exchanges''), Navigators, non-Navigator assistance personnel, and other entities under the Patient Protection and Affordable Care Act and the Health Care and Education Reconciliation Act of 2010 (collectively referred to as the Affordable Care Act). Specifically, the rule establishes standards related to product discontinuation and renewal, quality reporting, non-discrimination standards, minimum certification standards and responsibilities of qualified health plan (QHP) issuers, the Small Business Health Options Program, and enforcement remedies in Federally-facilitated Exchanges. It also finalizes: A modification of HHS's allocation of reinsurance collections if those collections do not meet our projections; certain changes to allowable administrative expenses in the risk corridors calculation; modifications to the way we calculate the annual limit on cost sharing so that we round this parameter down to the nearest $50 increment; an approach to index the required contribution used to determine eligibility for an exemption from the shared responsibility payment under section 5000A of the Internal Revenue Code; grounds for imposing civil money penalties on persons who provide false or fraudulent information to the Exchange and on persons who improperly use or disclose information; updated standards for the consumer assistance programs; standards related to the opt-out provisions for self-funded, non-Federal governmental plans and related to the individual market provisions under the Health Insurance Portability and Accountability Act of 1996 including excepted benefits; standards regarding how enrollees may request access to non-formulary drugs under exigent circumstances; amendments to Exchange appeals standards and coverage enrollment and termination standards; and time-limited adjustments to the standards relating to the medical loss ratio

  10. A study on equilibrium and kinetics of ion exchange of alkaline earth ...

    Indian Academy of Sciences (India)

    A study on equilibrium and kinetics of ion exchange of alkaline earth metals using an inorganic cation exchanger - zirconium titanium phosphate ... Further, various kinetic parameters like self-diffusion coefficient (0), energy of activation () and entropy of activation (*) have been evaluated under conditions favouring a ...

  11. Fault-Tolerant Heat Exchanger

    Science.gov (United States)

    Izenson, Michael G.; Crowley, Christopher J.

    2005-01-01

    A compact, lightweight heat exchanger has been designed to be fault-tolerant in the sense that a single-point leak would not cause mixing of heat-transfer fluids. This particular heat exchanger is intended to be part of the temperature-regulation system for habitable modules of the International Space Station and to function with water and ammonia as the heat-transfer fluids. The basic fault-tolerant design is adaptable to other heat-transfer fluids and heat exchangers for applications in which mixing of heat-transfer fluids would pose toxic, explosive, or other hazards: Examples could include fuel/air heat exchangers for thermal management on aircraft, process heat exchangers in the cryogenic industry, and heat exchangers used in chemical processing. The reason this heat exchanger can tolerate a single-point leak is that the heat-transfer fluids are everywhere separated by a vented volume and at least two seals. The combination of fault tolerance, compactness, and light weight is implemented in a unique heat-exchanger core configuration: Each fluid passage is entirely surrounded by a vented region bridged by solid structures through which heat is conducted between the fluids. Precise, proprietary fabrication techniques make it possible to manufacture the vented regions and heat-conducting structures with very small dimensions to obtain a very large coefficient of heat transfer between the two fluids. A large heat-transfer coefficient favors compact design by making it possible to use a relatively small core for a given heat-transfer rate. Calculations and experiments have shown that in most respects, the fault-tolerant heat exchanger can be expected to equal or exceed the performance of the non-fault-tolerant heat exchanger that it is intended to supplant (see table). The only significant disadvantages are a slight weight penalty and a small decrease in the mass-specific heat transfer.

  12. Dynamic Relationship between Crude Oil Price, Exchange Rate and ...

    African Journals Online (AJOL)

    DrNneka

    stock market performance (Adebiyi et al., 2009). This study contributed to the study of linkage between crude oil price movements, exchange rate behaviour and stock market performance of African oil-exporting countries. The increased integration of financial markets in the world today provides investors with new ways to ...

  13. AGU's Thriving Earth Exchange: Five Reasons to Join In

    Science.gov (United States)

    Pandya, Raj; Galkiewicz, Julia; Williams, Billy; Furukawa, Harry

    2013-11-01

    AGU has launched the Thriving Earth Exchange, a new initiative that supports communities as they protect themselves from hazards, adapt to a changing planet, and create sustainable futures. Through the program, AGU members will work with local leaders to contribute their Earth and space science expertise to these significant societal challenges.

  14. Electrically switched ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Lilga, M.A. [Pacific Northwest National Lab., Richland, WA (United States); Schwartz, D.T.; Genders, D.

    1997-10-01

    A variety of waste types containing radioactive {sup 137}Cs are found throughout the DOE complex. These waste types include water in reactor cooling basins, radioactive high-level waste (HLW) in underground storage tanks, and groundwater. Safety and regulatory requirements and economics require the removal of radiocesium before these wastes can be permanently disposed of. Electrically Switched Ion Exchange (ESIX) is an approach for radioactive cesium separation that combines IX and electrochemistry to provide a selective, reversible, and economic separation method that also produces little or no secondary waste. In the ESIX process, an electroactive IX film is deposited electrochemically onto a high-surface area electrode, and ion uptake and elution are controlled directly by modulating the potential of the film. For cesium, the electroactive films under investigation are ferrocyanides, which are well known to have high selectivities for cesium in concentrated sodium solutions. When a cathode potential is applied to the film, Fe{sup +3} is reduced to the Fe{sup +2} state, and a cation must be intercalated into the film to maintain charge neutrality (i.e., Cs{sup +} is loaded). Conversely, if an anodic potential is applied, a cation must be released from the film (i.e., Cs{sup +} is unloaded). Therefore, to load the film with cesium, the film is simply reduced; to unload cesium, the film is oxidized.

  15. Models for estimating photosynthesis parameters from in situ production profiles

    Science.gov (United States)

    Kovač, Žarko; Platt, Trevor; Sathyendranath, Shubha; Antunović, Suzana

    2017-12-01

    The rate of carbon assimilation in phytoplankton primary production models is mathematically prescribed with photosynthesis irradiance functions, which convert a light flux (energy) into a material flux (carbon). Information on this rate is contained in photosynthesis parameters: the initial slope and the assimilation number. The exactness of parameter values is crucial for precise calculation of primary production. Here we use a model of the daily production profile based on a suite of photosynthesis irradiance functions and extract photosynthesis parameters from in situ measured daily production profiles at the Hawaii Ocean Time-series station Aloha. For each function we recover parameter values, establish parameter distributions and quantify model skill. We observe that the choice of the photosynthesis irradiance function to estimate the photosynthesis parameters affects the magnitudes of parameter values as recovered from in situ profiles. We also tackle the problem of parameter exchange amongst the models and the effect it has on model performance. All models displayed little or no bias prior to parameter exchange, but significant bias following parameter exchange. The best model performance resulted from using optimal parameter values. Model formulation was extended further by accounting for spectral effects and deriving a spectral analytical solution for the daily production profile. The daily production profile was also formulated with time dependent growing biomass governed by a growth equation. The work on parameter recovery was further extended by exploring how to extract photosynthesis parameters from information on watercolumn production. It was demonstrated how to estimate parameter values based on a linearization of the full analytical solution for normalized watercolumn production and from the solution itself, without linearization. The paper complements previous works on photosynthesis irradiance models by analysing the skill and consistency of

  16. EU language policy and the language goals and gains of exchange students in Scandinavia

    DEFF Research Database (Denmark)

    Petersen, Margrethe; Shaw, Philip; Caudery, Tim

    To assess whether the Erasmus student exchange program contributes to EU’s language policy aim of furthering multilingualism/plurilingualism, this presentation draws on interviews with, and tests taken by, some 50 incoming exchange students in Scandinavia and employs Bourdieu’s concept of capital...... in explaining individual variation in students’ language goals and gains....

  17. Foreign Exchange Market Contagion in the Asian Crisis: A Regression-based Approach

    NARCIS (Netherlands)

    van Horen, N.; Jager, H.; Klaassen, F.J.G.M.

    2006-01-01

    This paper investigates whether, during the Asian crisis, contagion occurred from Thailand to the other crisis countries through the foreign exchange market, and, if so, determines the contribution of this contagion to the crisis. More specifically, we examine whether the effect of the exchange

  18. Effects of International Student Exchange on Pre-Service Teachers: A Quasi-Experimental Study

    Science.gov (United States)

    Leutwyler, Bruno; Meierhans, Claudia

    2016-01-01

    This contribution provides empirical answers to the question of how teaching-specific competencies develop during participation in an international student exchange programme. The quantitative analyses of this quasi-experimental study suggest that, generally speaking, no specific developments occur during an exchange experience. These findings…

  19. Social Exchange and Sexual Behavior in Young Women's Premarital Relationships in Kenya

    Science.gov (United States)

    Luke, Nancy; Goldberg, Rachel E.; Mberu, Blessing U.; Zulu, Eliya M.

    2011-01-01

    Transactional sex, or the exchange of money and gifts for sexual activities within nonmarital relationships, has been widely considered a contributing factor to the disproportionate prevalence of HIV/AIDS among young women in sub-Saharan Africa. This study applied social exchange theory to premarital relationships in order to investigate the…

  20. Use of Multi-Functional Flexible Micro-Sensors for in situ Measurement of Temperature, Voltage and Fuel Flow in a Proton Exchange Membrane Fuel Cell

    Science.gov (United States)

    Lee, Chi-Yuan; Chan, Pin-Cheng; Lee, Chung-Ju

    2010-01-01

    Temperature, voltage and fuel flow distribution all contribute considerably to fuel cell performance. Conventional methods cannot accurately determine parameter changes inside a fuel cell. This investigation developed flexible and multi-functional micro sensors on a 40 μm-thick stainless steel foil substrate by using micro-electro-mechanical systems (MEMS) and embedded them in a proton exchange membrane fuel cell (PEMFC) to measure the temperature, voltage and flow. Users can monitor and control in situ the temperature, voltage and fuel flow distribution in the cell. Thereby, both fuel cell performance and lifetime can be increased. PMID:22163545

  1. Multicomponent liquid ion exchange with chabazite zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, S.M.; Arnold, W.D. Jr.; Byers, C.W.

    1993-10-01

    In spite of the increasing commercial use of zeolites for binary and multicomponent sorption, the understanding of the basic mass-transfer processes associated with multicomponent zeolite ion-exchange systems is quite limited. This study was undertaken to evaluate Na-Ca-Mg-Cs-Sr ion exchange from an aqueous solution using a chabazite zeolite. Mass-transfer coefficients and equilibrium equations were determined from experimental batch-reactor data for single and multicomponent systems. The Langmuir isotherm was used to represent the equilibrium relationship for binary systems, and a modified Dubinin-Polyani model was used for the multicomponent systems. The experimental data indicate that diffusion through the microporous zeolite crystals is the primary diffusional resistance. Macropore diffusion also significantly contributes to the mass-transfer resistance. Various mass-transfer models were compared to the experimental data to determine mass-transfer coefficients. Effective diffusivities were obtained which accurately predicted experimental data using a variety of models. Only the model which accounts for micropore and macropore diffusion occurring in series accurately predicted multicomponent data using single-component diffusivities. Liquid and surface diffusion both contribute to macropore diffusion. Surface and micropore diffusivities were determined to be concentration dependent.

  2. Custom, contract, and kidney exchange.

    Science.gov (United States)

    Healy, Kieran; Krawiec, Kimberly D

    2012-01-01

    In this Essay, we examine a case in which the organizational and logistical demands of a novel form of organ exchange (the nonsimultaneous, extended, altruistic donor (NEAD) chain) do not map cleanly onto standard cultural schemas for either market or gift exchange, resulting in sociological ambiguity and legal uncertainty. In some ways, a NEAD chain resembles a form of generalized exchange, an ancient and widespread instance of the norm of reciprocity that can be thought of simply as the obligation to “pay it forward” rather than the obligation to reciprocate directly with the original giver. At the same time, a NEAD chain resembles a string of promises and commitments to deliver something in exchange for some valuable consideration--that is, a series of contracts. Neither of these salient "social imaginaries" of exchange--gift giving or formal contract--perfectly meets the practical demands of the NEAD system. As a result, neither contract nor generalized exchange drives the practice of NEAD chains. Rather, the majority of actual exchanges still resemble a simpler form of exchange: direct, simultaneous exchange between parties with no time delay or opportunity to back out. If NEAD chains are to reach their full promise for large-scale, nonsimultaneous organ transfer, legal uncertainties and sociological ambiguities must be finessed, both in the practices of the coordinating agencies and in the minds of NEAD-chain participants. This might happen either through the further elaboration of gift-like language and practices, or through a creative use of the cultural form and motivational vocabulary, but not necessarily the legal and institutional machinery, of contract.

  3. HEAT EXCHANGERS IN SEWAGE PIPES

    OpenAIRE

    Podobeková, Veronika; Peráčková, Jana

    2014-01-01

    The article discusses utilization of heat from waste water in sewage. During the year, temperature of water in sewage ranges between 10 °C and 20 °C and the heat from sewage could be used for heating, cooling and hot water preparation in building. The heat is extracted through a transfer surface area of the heat exchanger into the heat pump, which is able to utilize the low–potential energy. Different design and types of the heat exchangers in sewage are dealt with: heat exchangers embedded i...

  4. Relational and XML Data Exchange

    CERN Document Server

    Arenas, Marcelo

    2010-01-01

    Data exchange is the problem of finding an instance of a target schema, given an instance of a source schema and a specification of the relationship between the source and the target. Such a target instance should correctly represent information from the source instance under the constraints imposed by the target schema, and it should allow one to evaluate queries on the target instance in a way that is semantically consistent with the source data. Data exchange is an old problem that re-emerged as an active research topic recently, due to the increased need for exchange of data in various for

  5. Heat exchanger using graphite foam

    Science.gov (United States)

    Campagna, Michael Joseph; Callas, James John

    2012-09-25

    A heat exchanger is disclosed. The heat exchanger may have an inlet configured to receive a first fluid and an outlet configured to discharge the first fluid. The heat exchanger may further have at least one passageway configured to conduct the first fluid from the inlet to the outlet. The at least one passageway may be composed of a graphite foam and a layer of graphite material on the exterior of the graphite foam. The layer of graphite material may form at least a partial barrier between the first fluid and a second fluid external to the at least one passageway.

  6. Analytical and Numerical Design Analysis of Concentric Tube Heat Exchangers – A Review

    Science.gov (United States)

    Silaipillayarputhur, Karthik; Mughanam, Tawfiq Al; Mojil, Abdulaziz Al; Dhmoush, Mohammed Al

    2017-12-01

    This paper considers an analytical and a numerical approach in the design of a concentric tube heat exchanger. Sensible heat transfer is considered in the analysis and the heat exchanger is developed for actual operating conditions in a chemical plant. The heat exchanger is a concentric tube heat exchanger where hot oil exchanges heat with hot water. Hot oil is in the inner pipe and the heating medium, hot water, is in the outer pipe (annular side) of the heat exchanger. An analytical model employing effectiveness-number of transfer units (ε-NTU) approach and log mean temperature difference (LMTD) approach were employed in the design of the concentric tube heat exchanger. In the design process, performance charts were developed for concentric tube heat exchanger. Performance charts describe the performance of the heat exchanger in terms of crucial dimensionless parameters. Performance charts help to select the right number of transfer units (NTU) for the given heat exchanger. Both parallel and counter flow configurations were considered for the design analysis. Likewise, a numerical model was also considered in the design of the heat exchanger. The results from the analysis are presented and compared. From the results it can be seen that both numerical and analytical approaches produce the exact same results. The designer certainly has the flexibility to choose an appropriate design methodology based on the available inputs and requirements.

  7. Geothermal heat exchanger with coaxial flow of fluids

    Directory of Open Access Journals (Sweden)

    Pejić Dragan M.

    2005-01-01

    Full Text Available The paper deals with a heat exchanger with coaxial flow. Two coaxial pipes of the secondary part were placed directly into a geothermal boring in such a way that geothermal water flows around the outer pipe. Starting from the energy balance of the exchanger formed in this way and the assumption of a study-state operating regime, a mathematical model was formulated. On the basis of the model, the secondary circle output temperature was determined as a function of the exchanger geometry, the coefficient of heat passing through the heat exchange areas, the average mass isobaric specific heats of fluid and mass flows. The input temperature of the exchanger secondary circle and the temperature of the geothermal water at the exit of the boring were taken as known values. Also, an analysis of changes in certain factors influencing the secondary water temperature was carried out. The parameters (flow temperature of the deep boring B-4 in Sijarinska Spa, Serbia were used. The theoretical results obtained indicate the great potential of this boring and the possible application of such an exchanger.

  8. Asynchronous replica exchange software for grid and heterogeneous computing

    Science.gov (United States)

    Gallicchio, Emilio; Xia, Junchao; Flynn, William F.; Zhang, Baofeng; Samlalsingh, Sade; Mentes, Ahmet; Levy, Ronald M.

    2015-11-01

    Parallel replica exchange sampling is an extended ensemble technique often used to accelerate the exploration of the conformational ensemble of atomistic molecular simulations of chemical systems. Inter-process communication and coordination requirements have historically discouraged the deployment of replica exchange on distributed and heterogeneous resources. Here we describe the architecture of a software (named ASyncRE) for performing asynchronous replica exchange molecular simulations on volunteered computing grids and heterogeneous high performance clusters. The asynchronous replica exchange algorithm on which the software is based avoids centralized synchronization steps and the need for direct communication between remote processes. It allows molecular dynamics threads to progress at different rates and enables parameter exchanges among arbitrary sets of replicas independently from other replicas. ASyncRE is written in Python following a modular design conducive to extensions to various replica exchange schemes and molecular dynamics engines. Applications of the software for the modeling of association equilibria of supramolecular and macromolecular complexes on BOINC campus computational grids and on the CPU/MIC heterogeneous hardware of the XSEDE Stampede supercomputer are illustrated. They show the ability of ASyncRE to utilize large grids of desktop computers running the Windows, MacOS, and/or Linux operating systems as well as collections of high performance heterogeneous hardware devices.

  9. Extensions to the Dynamic Aerospace Vehicle Exchange Markup Language

    Science.gov (United States)

    Brian, Geoffrey J.; Jackson, E. Bruce

    2011-01-01

    The Dynamic Aerospace Vehicle Exchange Markup Language (DAVE-ML) is a syntactical language for exchanging flight vehicle dynamic model data. It provides a framework for encoding entire flight vehicle dynamic model data packages for exchange and/or long-term archiving. Version 2.0.1 of DAVE-ML provides much of the functionality envisioned for exchanging aerospace vehicle data; however, it is limited in only supporting scalar time-independent data. Additional functionality is required to support vector and matrix data, abstracting sub-system models, detailing dynamics system models (both discrete and continuous), and defining a dynamic data format (such as time sequenced data) for validation of dynamics system models and vehicle simulation packages. Extensions to DAVE-ML have been proposed to manage data as vectors and n-dimensional matrices, and record dynamic data in a compatible form. These capabilities will improve the clarity of data being exchanged, simplify the naming of parameters, and permit static and dynamic data to be stored using a common syntax within a single file; thereby enhancing the framework provided by DAVE-ML for exchanging entire flight vehicle dynamic simulation models.

  10. Air conditioning - window model. Part 2. Thermal exchange processes; Klimatechnik - Fenstermodell. Teil 2. Thermische Austauschvorgaenge

    Energy Technology Data Exchange (ETDEWEB)

    Stoll, J. [Georg-Simon-Ohm-Fachhochschule, Nuernberg (Germany)

    2005-07-01

    Modern external walls and windows require detailed calculations which cannot be based on out-of-date information. While the first part of this contribution discussed short-wave solar radiation, this sequel goes into thermal exchange processes. (orig.)

  11. Simultaneous Disulfide and Boronic Acid Ester Exchange in Dynamic Combinatorial Libraries

    DEFF Research Database (Denmark)

    Diemer, Sanna L.; Kristensen, Morten; Rasmussen, Brian

    2015-01-01

    that operate simultaneously or two reversible reactions that operate independently. Both these scenarios have advantages and disadvantages. In this contribution, we show how disulfide exchange and boronic ester transesterification can function simultaneous in dynamic combinatorial libraries under appropriate...

  12. A survey of oscillating flow in Stirling engine heat exchangers

    Science.gov (United States)

    Simon, Terrence W.; Seume, Jorge R.

    1988-01-01

    Similarity parameters for characterizing the effect of flow oscillation on wall shear stress, viscous dissipation, pressure drop and heat transfer rates are proposed. They are based on physical agruments and are derived by normalizing the governing equations. The literature on oscillating duct flows, regenerator and porous media flows is surveyed. The operating characteristics of the heat exchanger of eleven Stirling engines are discribed in terms of the similarity parameters. Previous experimental and analytical results are discussed in terms of these parameters and used to estimate the nature of the oscillating flow under engine operating conditions. The operating points for many of the modern Stirling engines are in or near the laminar to turbulent transition region. In several engines, working fluid does not pass entirely through heat exchangers during a cycle. Questions that need to be addressed by further research are identified.

  13. Pu Anion Exchange Process Intensification

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-08

    This project seeks to improve the efficiency of the plutonium anion-exchange process for purifying Pu through the development of alternate ion-exchange media. The objective of the project in FY15 was to develop and test a porous foam monolith material that could serve as a replacement for the current anion-exchange resin, Reillex® HPQ, used at the Savannah River Site (SRS) for purifying Pu. The new material provides advantages in efficiency over the current resin by the elimination of diffusive mass transport through large granular resin beads. By replacing the large resin beads with a porous foam there is much more efficient contact between the Pu solution and the anion-exchange sites present on the material. Several samples of a polystyrene based foam grafted with poly(4-vinylpyridine) were prepared and the Pu sorption was tested in batch contact tests.

  14. Liquid droplet heat exchanger studies

    Science.gov (United States)

    Bruckner, A. P.; Hedges, D. E.; Yungster, S.

    1987-01-01

    Recent analytical and experimental investigations of the liquid droplet heat exchanger (LDHX) concept for space power applications are described. The performance of the LDHX is compared to that of a conventional heat exchanger for heat rejection applications in a Brayton cycle, using the mass-specific heat exchanger effectiveness as a figure of merit. It is shown that the LDHX has an order of magnitude advantage over the conventional heat exchanger. Furthermore, significant improvement in cycle efficiency and power to mass ratio is possible. Two-phase flow experiments in a laboratory scale LDHX, using air and water as the two media, show very good agreement with the quasi-one-dimensional model used in the parametric studies.

  15. Estimating Foreign Exchange Reserve Adequacy

    Directory of Open Access Journals (Sweden)

    Abdul Hakim

    2013-04-01

    Full Text Available Accumulating foreign exchange reserves, despite their cost and their impacts on other macroeconomics variables, provides some benefits. This paper models such foreign exchange reserves. To measure the adequacy of foreign exchange reserves for import, it uses total reserves-to-import ratio (TRM. The chosen independent variables are gross domestic product growth, exchange rates, opportunity cost, and a dummy variable separating the pre and post 1997 Asian financial crisis. To estimate the risky TRM value, this paper uses conditional Value-at-Risk (VaR, with the help of Glosten-Jagannathan-Runkle (GJR model to estimate the conditional volatility. The results suggest that all independent variables significantly influence TRM. They also suggest that the short and long run volatilities are evident, with the additional evidence of asymmetric effects of negative and positive past shocks. The VaR, which are calculated assuming both normal and t distributions, provide similar results, namely violations in 2005 and 2008.

  16. VLER Health Exchange by Area

    Data.gov (United States)

    Department of Veterans Affairs — “Connect Your Docs” through the Virtual Lifetime Electronic Record (VLER) Health Exchange program. This program gives VA and community health care providers secure...

  17. Counterflow Regolith Heat Exchanger Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat...

  18. Virtual Photon Contribution to Frictional Drag in Double-layer Devices

    DEFF Research Database (Denmark)

    Donarini, Andrea; Ferrari, R.; Jauho, Antti-Pekka

    2003-01-01

    Frictional drag between coupled two-dimensional charge systems is commonly viewed as a second order effect arising either from screened Coulomb interaction, or phonon exchange. We point out that for single-photon exchange the first order contribution does not have to vanish even at T = 0, and eva......Frictional drag between coupled two-dimensional charge systems is commonly viewed as a second order effect arising either from screened Coulomb interaction, or phonon exchange. We point out that for single-photon exchange the first order contribution does not have to vanish even at T = 0...

  19. International Prices and Exchange Rates

    OpenAIRE

    Gopinath, Gita; Burstein, Ariel

    2013-01-01

    We survey the recent empirical and theoretical developments in the literature on the relation between prices and exchange rates. After updating some of the major findings in the empirical literature we present a simple framework to interpret this evidence. We review theoretical models that generate insensitivity of prices to exchange rate changes through variable markups, both under flexible prices and nominal rigidities, first in partial equilibrium and then in general equilibrium.

  20. Exchange rate determination in Vietnam

    OpenAIRE

    Thai-Ha Le

    2015-01-01

    This study investigates the determinants of the exchange rate in Vietnam and suggests policy implications. Gregory-Hansen cointegration tests and generalised variance decomposition (VDC) analysis were applied to monthly data from July 2004 to December 2013. The model was built based on the three popular approaches to exchange rate determination, which are purchasing power parity (PPP) approach, balance of payment (BOP) approach, and monetary and portfolio approach. This study finds that the p...

  1. Shared Year Exchange in Nursing

    DEFF Research Database (Denmark)

    Vedsegaard, Helle Wendner; Wederkinck, Elisabeth

    2010-01-01

    Beskrivelse af Shared Year Exchange in Nursing, et udviklingsporjekt omhandlende udvikling, beskrivelse og implementering af et fælles studieår for sygeplejerskestuderende ved Metropol og La Trobe University Australien.......Beskrivelse af Shared Year Exchange in Nursing, et udviklingsporjekt omhandlende udvikling, beskrivelse og implementering af et fælles studieår for sygeplejerskestuderende ved Metropol og La Trobe University Australien....

  2. Redefining solubility parameters: the partial solvation parameters.

    Science.gov (United States)

    Panayiotou, Costas

    2012-03-21

    The present work reconsiders a classical and universally accepted concept of physical chemistry, the solubility parameter. Based on the insight derived from modern quantum chemical calculations, a new definition of solubility parameter is proposed, which overcomes some of the inherent restrictions of the original definition and expands its range of applications. The original single solubility parameter is replaced by four partial solvation parameters reflecting the dispersion, the polar, the acidic and the basic character of the chemical compounds as expressed either in their pure state or in mixtures. Simple rules are adopted for the definition and calculation of these four parameters and their values are tabulated for a variety of common substances. In contrast, however, to the well known Hansen solubility parameters, their design and evaluation does not rely exclusively on the basic rule of "similarity matching" for solubility but it makes also use of the other basic rule of compatibility, namely, the rule of "complementarity matching". This complementarity matching becomes particularly operational with the sound definition of the acidic and basic components of the solvation parameter based on the third σ-moments of the screening charge distributions of the quantum mechanics-based COSMO-RS theory. The new definitions are made in a simple and straightforward manner, thus, preserving the strength and appeal of solubility parameter stemming from its simplicity. The new predictive method has been applied to a variety of solubility data for systems of pharmaceuticals and polymers. The results from quantum mechanics calculations are critically compared with the results from Abraham's acid/base descriptors.

  3. Resonant electronic excitation energy transfer by exchange mechanism in the quantum dot system

    Science.gov (United States)

    Chikalova-Luzina, O. P.; Samosvat, D. M.; Vyatkin, V. M.; Zegrya, G. G.

    2017-11-01

    A microscopic theory of nonradiative resonance energy transfer between spherical A3B5 semiconductor quantum dots by the exchange mechanism is suggested. The interdot Coulomb interaction is taken into consideration. It is assumed that the quantum dot-donor and the quantum dot-acceptor are made from the same A3B5 compound and are embedded in the matrix of another material that produces potential barriers for electrons and holes. The dependences of the energy transfer rate on the quantum-dot system parameters are found in the frame of the Kane model that provides the most adequate description of the real spectra of A3B5 semiconductors. The analytical treatment is carried out with using the density matrix method, which enabled us to perform an energy transfer analysis both in the weak-interaction approximation and in the strong-interaction approximation. The numerical calculations showed the saturation of the energy transfer rate at the distances between the donor and the acceptor approaching the contact one. The contributions of the exchange and direct Coulomb intractions can be of the same order at the small distances and can have the same value in the saturation range.

  4. Exchange Perturbation Theory for Multiatomic Electron System and Its Application to Spin Arrangement in Manganite Chains

    Directory of Open Access Journals (Sweden)

    E. V. Orlenko

    2011-01-01

    Full Text Available A new methodology of binding energy calculation with respect to different spin arrangements for a multiatomic electron system is developed from the first principle in the frame of the exchange perturbation theory (EPT. We developed EPT formalism in the general form of the Rayleigh-Srchödinger expansion with a symmetric Hamiltonian, taking into account an exchange and nonadditive contributions of a superexchange interaction. The expressions of all corrections to the energy and wave function were reduced to the nonsymmetric Hamiltonian form. The EPT method is extended for the case of degeneracy in the total spin of a system. As an example of the application of the developed EPT formalism for the degeneracy case, spin arrangements were considered for the key ⟨Mn⟩–O–⟨Mn⟩ (⟨Mn⟩: Mn3+ or Mn4+ fragments in manganites. In ⟨Mn⟩–O–⟨Mn⟩ for La1/3Ca2/3MnO3 are in good agreement the obtained estimations of Heisenberg parameter and binding energy with the available experimental data.

  5. Stochastic Model of Maturation and Vesicular Exchange in Cellular Organelles

    CERN Document Server

    Vagne, Quentin

    2016-01-01

    The dynamical organization of membrane-bound organelles along intracellular transport pathways relies on vesicular exchange between organelles and on biochemical maturation of the organelle content by specific enzymes. The relative importance of each mechanism in controlling organelle dynamics remains controversial, in particular for transport through the Golgi apparatus. Using a stochastic model, we show that full maturation of membrane-bound compartments can be seen as the stochastic escape from a steady-state in which export is dominated by vesicular exchange. We show that full maturation can contribute a significant fraction of the total out-flux for small organelles such as endosomes and Golgi cisternae.

  6. Exchange Rate Exposure Management: "Speculation" in Non-Financial Companies

    DEFF Research Database (Denmark)

    Aabo, Tom

    "Speculation" in non-financial companies in relation to exchange rate exposure management constitutes one of the contributing factors behind corporate (or more widespread) crises. Deviations from benchmark positions constitute speculation. An empirical study of Danish non-financial companies finds...... that the larger the company (ability) and the larger its relative sale on foreign markets (relevance), the more likely the company will be to benchmark its exchange rate exposures. However, at the same time the very same factors (size and foreign sale) lead to more extensive speculation. Financial solvency (value...

  7. Going on exchange to Scandinavia to improve language skills

    DEFF Research Database (Denmark)

    Caudery, Tim; Petersen, Margrethe; Shaw, Philip

    Most exchange students now come to Scandinavian countries not because they are students of the languages of the countries concerned, but because they wish to experience study abroad and can do so in Scandinavia through the medium of English used as a lingua franca. This paper reports on a three-y...... for their interactions? What contributions do these exchanges make to European goals of promoting 'mother tongue plus two'? The paper sheds some light upon these questions and considers the implications of the answers found thus far....

  8. The effect of the correlation and exchange interactions on the electronic and magnetic properties of the hexagonal NiS using the onsite exact exchange/hybrid functionals

    Science.gov (United States)

    Reggad, A.; Lardjani, R.; Baghdad, R.; Bouhafs, B.

    2017-12-01

    We have performed ab initio calculations using the onsite exact exchange/hybrid functionals within the density functional theory to study the effect of the correlation and exchange interactions on the structural, electronic and magnetic properties of the hexagonal nickel sulphide (NiS) by varying the Fock exchange parameter value. The Perdew- Burke- Ernzerhof (PBE) calculation shows that the non magnetic state is the most stable, but the application of the onsite exact exchange/hybrid functionals for the correlated d electrons leads to get the anti-ferromagnetic AFM I state the most stable which is consistent with the experimental results. To get the semiconductor state we should use a α parameter value more than 0.05 which represents 5% of the Fock exchange. The α parameter has a big effect on the unit cell volume but there is a little effect on the c/a ratio. The magnetic moment and band gap are widely influenced by the exchange and correlation interactions. We have also investigated the effect of the lattice parameters on the magnetic and electronic properties.

  9. Positive and negative exchanges in social relationships as predictors of depression: evidence from the English Longitudinal Study of Aging.

    Science.gov (United States)

    Stafford, Mai; McMunn, Anne; Zaninotto, Paola; Nazroo, James

    2011-06-01

    To investigate whether the impact of negative and positive social exchanges on depression depends on relationship type among late middle age and older adults. Using data from the English Longitudinal Study of Aging, baseline positive and negative exchanges with partners, children, other family and friends were linked to 2-year changes in depression on the eight-item Center for Epidemiologic Studies Depression Scale. Positive and negative exchanges with partners and with children were independently associated with depression, adjusting for age, gender, wealth, and baseline depression. Negative but not positive exchanges with other family and with friends were associated with depression. The association between depression and positive/negative exchanges was weaker among the above 70s compared with those aged 50 to 70. Negative and positive exchanges with partners and children appear equally salient for depression onset although negative exchanges with family and friends contribute to depression whereas positive exchanges do not.

  10. Metasurfaces: Simultaneous Stokes parameters

    Science.gov (United States)

    Lepetit, Thomas; Kanté, Boubacar

    2015-11-01

    Techniques for determining Stokes parameters, which fully define the polarization state of a wave, require multiple measurements, thus potentially leading to inaccuracies. Researchers now show how to simultaneously determine the parameters for visible light using periodic metal structures.

  11. International common cause failure data exchange project motor operated valves status

    Energy Technology Data Exchange (ETDEWEB)

    Tirira, J. [CEA Fontenay aux Roses, Inst. de Protection et de Surete Nucleaire, 92 (France); Kreuser, A. [GRS, Cologne (Germany)

    2001-07-01

    This paper presents a study performed on the set of common cause failures (CCF) of motor operated valves (MOV). The data studied here are derived from the International CCF Data Exchange (ICDE) database, to which several countries have submitted CCF event data. The purpose of the ICDE is to allow contributing countries to collaborate and exchange CCF data to enhance the quality of risk analyses that include CCF modelling. The project was established so that CCFs of key components in the main systems (e.g., centrifugal pumps, emergency diesels generators, etc) would be collected and exchanged among the participating countries. Because CCF events are typically rare events, most countries do not experience enough CCF events to perform meaningful analyses. Data combined from several countries, however, yields sufficient material for more rigorous analyses. This report is the result of an in-depth review of the MOV events and presents several insights about them. This study begins with an overview of the data set. Charts and tables are provided which show the event count for the event parameters. The database contains information developed during the original entry of the events that was used in this study. This information includes detection method, root cause, coupling factor, size and corrective action. As part of this study, these events were reviewed and additional categories of the data were included. These categories include the degree of failure, affected sub-component, kind of human failure, and kind of technical failure. In particular, this study synthesizes the major insights regarding root causes, coupling factors, and correctives actions. (authors)

  12. Comprehensive investigation of the corrosion state of the heat exchanger tubes of steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Nemeth, Z.; Varga, K.; Baja, B.; Rado, K. [Pannonia Univ., Institute of Radiochemistry and Radioecology, Veszprem (Hungary); Szabo, N.A. [Istvan Szechenyi Univ., Dept. of Physics and Chemistry, Gyor (Hungary); Homonnay, Z.; Kuzmann, E. [Eotvos Lorand Univ., Institute of Chemistry, Budapest (Hungary); Patek, G.; Schunk, J. [Paks NPP Ltd., Paks (Hungary)

    2009-07-01

    Evaluating the water chemistry in the primary circuit and the effect of chemical decontamination of the heat exchanger tubes performed by the AP-CITROX procedure at Paks NPP (Hungary), a project dealing with the comprehensive investigation of the general corrosion state of the steam generators (SGs) has been initiated. Owing to the fact that there is no investigation method available for the in-situ monitoring of the inner surfaces of heat exchanger tubes, a research program based on sampling as well as on ex-situ electrochemical and surface analytical measurements were developed and elaborated. In the time period of 2000-2008 - within the frame of the above project - 45 stainless steel specimens, cut out from various locations of the steam generators of the Paks NPP were investigated. Besides to the corrosion characteristics (corrosion rate, thickness and chemical composition of the protective oxide-layer) surface properties (morphology, chemical and phase compositions) of the passive layer formed on the inner surface of above heat exchanger tubes were studied, too. The passivity of the inside surface of the stainless steel specimens was measured by voltammetry, the morphology, chemical and phase compositions of the oxide layer formed on the surface were analyzed by SEM-EDX, XRD and CEMS methods. The great number of experimental results allowed us to develop an electronic database which involves the results of the above corrosion experiments, and also some special characteristics of the tubes (e.g. location in the SGs, surface pretreatment by decontamination, if any, etc). Evaluating the main relations among these parameters may contribute to the identification of important processes affecting the corrosion state of steam generators, and highly decisive concerning a life time prolongation project of VVER-type nuclear reactors. In the present work we provide a brief overview on these experiments, some characteristic results, the database developed, as well as some

  13. Analysis and optimization of the heat transfer coefficient of a finned heat exchanger submitted to natural convection; Analise e otimizacao do coeficiente de transferencia de calor de um trocador aletado submetido a conveccao natural

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Alan Carlos Bueno da

    1997-07-01

    A heat transfer (condenser) of a domestic freezer was tested in a vertical channel in order to study the influence of the chimney effect in the optimization of the heat transfer coefficient. The variation of the opening of the channel, position and the heating power of the heat exchanger in the heat transfer coefficient was considered. The influence of the surface emissivity on the heat transfer by thermal radiation was studied with the heat exchanger testes without paint and with black paint. The air velocity entering the channel was measured with a hot wire anemometer. In order to evaluate the chimney effect, the heat exchanger was testes in a open ambient. This situation simulates its operational conditions when installed on the freezer system. The variables collected in the experimental procedures was gathered in the form of dimensionless parameters as Nusselt, Rayleigh, Grashof and Prandtl numbers, and dimensional parameters of the convection. The results showed that the highest heat transfer value occurred when both a specific position and a specific channel opening were used. The experiments pointed out that the radiation contribution must be considered in heat transfer calculations. The conclusions showed that different channel openings can improve the heat transfer coefficient in this heat transfer exchanger. (author)

  14. THE CHALLENGES FOR WOMEN IN EXECUTIVE POSITIONS AND THE ROLE OF GENDER ON LEADER MEMBER EXCHANGE

    Directory of Open Access Journals (Sweden)

    Buket AKDÖL

    2017-12-01

    Full Text Available This study concentrates on the potential effects of glass ceiling and queen bee syndrome in establishing high quality exchange (leader member exchange with subordinates. The study analyses if gender plays a significant role in determining exchange with subordinates.  Data was collected from white-collar employees at Turkish business context by using Liden Maslyn (1998 multi-dimension Leader Member Exchange assessment tool.  The findings of the study exhibit that in Turkish business context leader's gender is insignificant at determining exchange with white-collar subordinates for dimensions such as affection, contribution, loyalty and professional respect. The study also concludes gender of the subordinates is insignificant at determining the exchange with leaders of both genders

  15. Enhancement of Heat Exchanger Control Using Improved PID Controller

    Directory of Open Access Journals (Sweden)

    Gopalakrishna G.

    2009-08-01

    Full Text Available The Proportional, Integral and Derivative (PID controllers are widely used in industrial applications. Their popularity comes from their robust performance and also from their functional simplicity. Temperature control of double tube heat exchanger system is presented and ant colony algorithm for optimizing PID parameters of temperature controller is presented in this paper on the basis of conventional PID controller. Temperature controller based on ant colony optimization for double tube heat exchanger is designed. Simulation results show that, for the case of heat exchanger system, ACO-PID is good model and generalize well. The closed loop unit step response obtained with the proposed PID compares favorably with the one achieved using a conventional PID controller with dynamic closed-loop simulation. More important, the proposed approach takes a fraction of the time spent by the standard technique, without the need of perturbing the closed-loop system.

  16. The use of fibrous ion exchangers in gold hydrometallurgy

    Science.gov (United States)

    Kautzmann, R. M.; Sampaio, C. H.; Cortina, J. L.; Soldatov, V.; Shunkevich, A.

    2002-10-01

    This article examines a family of ion-exchange fibers, FIBAN, containing primary and secondary amine groups. These ion exchangers have a fiber diameter of 20 40 Μm, high osmotic and mechanic stability, a high rate of adsorption and regeneration, and excellent dynamic characteristics as filtering media. Inparticular, this article discusses the use of FIBAN fibrous ion exchangers in the recovery of gold cyanide andbase-metal cyanides (copper and mercury) from mineral-leaching solutions. The influence of polymer structure and water content on their extraction ability is described, along with key parameters of gold hydrometallurgy such as extraction efficiency, selectivity, pH dependence, gold cyanide loading, kinetics, and stripping.

  17. Thermodynamic analysis and optimization of air-cooled heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Salimpour, Mohammad Reza; Bahrami, Zabihollah [Isfahan University of Technology, Department of Mechanical Engineering, Isfahan (Iran, Islamic Republic of)

    2011-01-15

    In the present study, a thermodynamic second-law analysis was performed to investigate the effects of different geometry and flow parameters on the air-cooled heat exchanger performance. For this purpose, the entropy generation due to heat transfer and pressure loss of internal and external flows of the air-cooled heat exchanger was calculated; and it was observed that the total entropy generation has a minimum at special tube-side Reynolds number. Also, it was seen that the increasing of the tube-side Reynolds number resulted in the rise of the irreversibility of the air-cooled heat exchanger. The results also showed when air-side Reynolds number decreased, the entropy generation rate of the external flow reduced. Finally, based on the computed results, a new correlation was developed to predict the optimum Reynolds number of the tube-side fluid flow. (orig.)

  18. Heat exchanger selection and design analyses for metal hydride heat pump systems

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Voskuilen, Tyler G.; Waters, Essene L.

    2016-01-01

    This study presents a design analysis for the development of highly efficient heat exchangers within stationary metal hydride heat pumps. The design constraints and selected performance criteria are applied to three representative heat exchangers. The proposed thermal model can be applied to select...... the most efficient heat exchanger design and provides outcomes generally valid in a pre-design stage. Heat transfer effectiveness is the principal performance parameter guiding the selection analysis, the results of which appear to be mildly (up to 13%) affected by the specific Nusselt correlation used....... The thermo-physical properties of the heat transfer medium and geometrical parameters are varied in the sensitivity analysis, suggesting that the length of independent tubes is the physical parameter that influences the performance of the heat exchangers the most. The practical operative regions for each...

  19. Leaf gas exchange and chlorophyll a fluorescence in wheat plants supplied with silicon and infected with Pyricularia oryzae.

    Science.gov (United States)

    Perez, Carlos Eduardo Aucique; Rodrigues, Fabrício Ávila; Moreira, Wiler Ribas; DaMatta, Fábio Murilo

    2014-02-01

    This study investigated the effect of silicon (Si) on the photosynthetic gas exchange parameters (net CO2 assimilation rate [A], stomatal conductance to water vapor [gs], internal CO2 concentration [Ci], and transpiration rate [E]) and chlorophyll fluorescence a parameters (maximum quantum quenching [Fv/Fm and Fv'/Fm'], photochemical [qP] and nonphotochemical [NPQ] quenching coefficients, and electron transport rate [ETR]) in wheat plants grown in a nutrient solution containing 0 mM (-Si) or 2 mM (+Si) Si and noninoculated or inoculated with Pyricularia oryzae. Blast severity decreased due to higher foliar Si concentration. For the inoculated +Si plants, A, gs, and E were significantly higher in contrast to the inoculated -Si plants. For the inoculated +Si plants, significant differences of Fv/Fm between the -Si and +Si plants occurred at 48, 96, and 120 h after inoculation (hai) and at 72, 96, and 120 hai for Fv'/Fm'. The Fv/Fm and Fv'/Fm', in addition to total chlorophyll concentration (a + b) and the chlorophyll a/b ratio, significantly decreased in the -Si plants compared with the +Si plants. Significant differences between the -Si and +Si inoculated plants occurred for qP, NPQ, and ETR. The supply of Si contributed to decrease blast severity in addition to improving gas exchange performance and causing less dysfunction at the photochemical level.

  20. Microscopic insight into role of protein flexibility during ion exchange chromatography by nuclear magnetic resonance and quartz crystal microbalance approaches.

    Science.gov (United States)

    Hao, Dongxia; Ge, Jia; Huang, Yongdong; Zhao, Lan; Ma, Guanghui; Su, Zhiguo

    2016-03-18

    Driven by the prevalent use of ion exchange chromatography (IEC) for polishing therapeutic proteins, many rules have been formulated to summarize the different dependencies between chromatographic data and various operational parameters of interest based on statically determined interactions. However, the effects of the unfolding of protein structures and conformational stability are not as well understood. This study focuses on how the flexibility of proteins perturbs retention behavior at the molecular scale using microscopic characterization approaches, including hydrogen-deuterium (H/D) exchange detected by NMR and a quartz crystal microbalance (QCM). The results showed that a series of chromatographic retention parameters depended significantly on the adiabatic compressibility and structural flexibility of the protein. That is, softer proteins with higher flexibility tended to have longer retention times and stronger affinities on SP Sepharose adsorbents. Tracing the underlying molecular mechanism using NMR and QCM indicated that an easily unfolded flexible protein with a more compact adsorption layer might contribute to the longer retention time on adsorbents. The use of NMR and QCM provided a previously unreported approach for elucidating the effect of protein structural flexibility on binding in IEC systems. Copyright © 2016. Published by Elsevier B.V.

  1. Assessing the Sodium Exchange Capacity in Rainfed and Irrigated Soils in the Mediterranean Basin Using GIS

    Directory of Open Access Journals (Sweden)

    Luís Loures

    2017-03-01

    Full Text Available The soil exchange complex consists of colloidal materials on which ion exchange phenomena occur allowing it to attract, retain, and exchange elements that have opposite electric charges. Since their mineral constituents (clay and organic components (humus are mainly of a negative nature retained or exchanged ion are predominantly cations. Historically, failing to monitor parameters like the exchange sodium percentage (ESP has led to the permanent deterioration of soils which have become completely unproductive, largely reducing the sustainability of the agricultural systems. This study assesses how the sodium exchange capacity in irrigated soils differs from the rainfed ones through a sample survey that was carried out in the 15,031 ha of the Caia Irrigation Perimeter and adjacent areas, located in the municipalities of Elvas and Campo Maior, Portalegre District, Portugal where 14,280 georeferenced samples were collected from the top soil layer (0–20 cm, which were mixed 10 at a time so that each composite sample representing 11.1 ha. Then the samples were analyzed regarding the most relevant parameters for characterizing the soil exchange complex including the concentrations of exchanged bases and Cation Exchange Capacity (CEC. The results were arranged in a georeferenced grid with 1451 entries. Using classical statistical analysis and Geographic Information Systems (GIS software, it was possible to relate the individual soil samples analyzed with the cultural system practiced (irrigated or rainfed and the present soil group which permitted us to analyze the influence of the cultural system in the soil exchange complex. The distribution chart of the exchange sodium and CEC were created. The obtained results confirm a general decrease of CEC values and an increase of the exchangeable sodium content of irrigated explored soils when compared to the rainfed ones, putting forward noteworthy ideas not only regarding the necessary changes towards

  2. Understanding Oceanographic Contribution to Polar Motion

    Science.gov (United States)

    Kwon, S. R.; Chambers, D. P.

    2013-12-01

    Many studies have shown that mass redistribution within the oceans and ocean currents are significant contributors to polar motion. Chambers and Willis (2009) have previously identified a significant low-frequency mass exchange between the Pacific and Indo-Atlantic Oceans. Here, we examine how much this large-scale mass exchange contributes to polar motion by using ocean bottom pressure data from a model for 1993 to 2011. We find that the interbasin exchange of mass explains nearly 53% of the y-component of polar motion driven by ocean mass variations, but less than 3% the x-component. On the other hand, redistribution of mass within the Pacific alone explains nearly 60% of the variance in the x-component driven by ocean mass variations. The remainder of the variance is explained by redistribution within the Indo-Atlantic Ocean. The motion component of polar motion based on currents from the same model was also calculated using only data from areas poleward of of 30°S to the contribution of the Antarctic Circumpolar Current on polar motion.

  3. Parameters-related uncertainty in modeling sugar cane yield with an agro-Land Surface Model

    Science.gov (United States)

    Valade, A.; Ciais, P.; Vuichard, N.; Viovy, N.; Ruget, F.; Gabrielle, B.

    2012-12-01

    Agro-Land Surface Models (agro-LSM) have been developed from the coupling of specific crop models and large-scale generic vegetation models. They aim at accounting for the spatial distribution and variability of energy, water and carbon fluxes within soil-vegetation-atmosphere continuum with a particular emphasis on how crop phenology and agricultural management practice influence the turbulent fluxes exchanged with the atmosphere, and the underlying water and carbon pools. A part of the uncertainty in these models is related to the many parameters included in the models' equations. In this study, we quantify the parameter-based uncertainty in the simulation of sugar cane biomass production with the agro-LSM ORCHIDEE-STICS on a multi-regional approach with data from sites in Australia, La Reunion and Brazil. First, the main source of uncertainty for the output variables NPP, GPP, and sensible heat flux (SH) is determined through a screening of the main parameters of the model on a multi-site basis leading to the selection of a subset of most sensitive parameters causing most of the uncertainty. In a second step, a sensitivity analysis is carried out on the parameters selected from the screening analysis at a regional scale. For this, a Monte-Carlo sampling method associated with the calculation of Partial Ranked Correlation Coefficients is used. First, we quantify the sensitivity of the output variables to individual input parameters on a regional scale for two regions of intensive sugar cane cultivation in Australia and Brazil. Then, we quantify the overall uncertainty in the simulation's outputs propagated from the uncertainty in the input parameters. Seven parameters are identified by the screening procedure as driving most of the uncertainty in the agro-LSM ORCHIDEE-STICS model output at all sites. These parameters control photosynthesis (optimal temperature of photosynthesis, optimal carboxylation rate), radiation interception (extinction coefficient), root

  4. Electrical and thermal control of magnetic exchange interactions.

    Science.gov (United States)

    Fransson, Jonas; Ren, Jie; Zhu, Jian-Xin

    2014-12-19

    We investigate the far-from-equilibrium nature of magnetic anisotropy and exchange interactions between molecular magnets embedded in a tunnel junction. By mapping to an effective spin model, these magnetic interactions can be divided into three types: isotropic Heisenberg, anisotropic Ising, and anisotropic Dzyaloshinski-Moriya contributions, which are attributed to the background nonequilibrium electronic structures. We further demonstrate that both the magnetic self- and exchange interactions can be controlled either electrically by gating and tuning the voltage bias, or thermally by adjusting the temperature bias. We show that the Heisenberg and Ising interactions scale linearly, while the Dzyaloshinski-Moriya interaction scales quadratically, with the molecule-lead coupling strength. The interactions scale linearly with the effective spin polarizations of the leads and the molecular coherence. Our results pave a way for smart control of magnetic exchange interactions at atomic and molecular levels.

  5. Biological insights from hydrogen exchange mass spectrometry.

    Science.gov (United States)

    Jaswal, Sheila S

    2013-06-01

    Over the past two decades, hydrogen exchange mass spectrometry (HXMS) has achieved the status of a widespread and routine approach in the structural biology toolbox. The ability of hydrogen exchange to detect a range of protein dynamics coupled with the accessibility of mass spectrometry to mixtures and large complexes at low concentrations result in an unmatched tool for investigating proteins challenging to many other structural techniques. Recent advances in methodology and data analysis are helping HXMS deliver on its potential to uncover the connection between conformation, dynamics and the biological function of proteins and complexes. This review provides a brief overview of the HXMS method and focuses on four recent reports to highlight applications that monitor structure and dynamics of proteins and complexes, track protein folding, and map the thermodynamics and kinetics of protein unfolding at equilibrium. These case studies illustrate typical data, analysis and results for each application and demonstrate a range of biological systems for which the interpretation of HXMS in terms of structure and conformational parameters provides unique insights into function. This article is part of a Special Issue entitled: Mass spectrometry in structural biology. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Innovation as the object of market exchange

    Directory of Open Access Journals (Sweden)

    Jerzy Koszałka

    2014-03-01

    Full Text Available The article discusses the problem of the characteristics of innovation as products that the world increasingly also in Poland, are the object of market exchange. They differ substantially from the products offered by the production and service companies in the markets of consumer goods, also ready-made industrial goods. The key differences are due to the fact, that innovation can be a product — market traded object already as an idea and concept, or as a solution in different phases of development and growth. This will involve a high degree of uncertainty as to all aspects of the pro-innovation project in the development process. This applies above all intellectual property rights in the development process of innovation, functionality and technical parameters of solutions, manufacturability of solutions, affecting the ability of their production, marketing aspects, as well as the economic and financial aspects. In addition, the theoretical issues related to innovation as products — objects of the market exchange are discussed with examples from practice Gdansk University of Technology, who is the creator and provider of innovative solutions for the industrial market. There are characterized changes in knowledge, uncertainty and risk, resulting from the process of innovation. The article ends with conclusions.

  7. Fair Exchange in Strand Spaces

    Directory of Open Access Journals (Sweden)

    Joshua D. Guttman

    2009-10-01

    Full Text Available Many cryptographic protocols are intended to coordinate state changes among principals. Exchange protocols coordinate delivery of new values to the participants, e.g. additions to the set of values they possess. An exchange protocol is fair if it ensures that delivery of new values is balanced: If one participant obtains a new possession via the protocol, then all other participants will, too. Fair exchange requires progress assumptions, unlike some other protocol properties. The strand space model is a framework for design and verification of cryptographic protocols. A strand is a local behavior of a single principal in a single session of a protocol. A bundle is a partially ordered global execution built from protocol strands and adversary activities. The strand space model needs two additions for fair exchange protocols. First, we regard the state as a multiset of facts, and we allow strands to cause changes in this state via multiset rewriting. Second, progress assumptions stipulate that some channels are resilient-and guaranteed to deliver messages-and some principals are assumed not to stop at certain critical steps. This method leads to proofs of correctness that cleanly separate protocol properties, such as authentication and confidentiality, from invariants governing state evolution. G. Wang's recent fair exchange protocol illustrates the approach.

  8. Pu Anion Exchange Process Intensification

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, Kathryn M. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-10-06

    This research is focused on improving the efficiency of the anion exchange process for purifying plutonium. While initially focused on plutonium, the technology could also be applied to other ion-exchange processes. Work in FY17 focused on the improvement and optimization of porous foam columns that were initially developed in FY16. These foam columns were surface functionalized with poly(4-vinylpyridine) (PVP) to provide the Pu specific anion-exchange sites. Two different polymerization methods were explored for maximizing the surface functionalization with the PVP. The open-celled polymeric foams have large open pores and large surface areas available for sorption. The fluid passes through the large open pores of this material, allowing convection to be the dominant mechanism by which mass transport takes place. These materials generally have very low densities, open-celled structures with high cell interconnectivity, small cell sizes, uniform cell size distributions, and high structural integrity. These porous foam columns provide advantages over the typical porous resin beads by eliminating the slow diffusion through resin beads, making the anion-exchange sites easily accessible on the foam surfaces. The best performing samples exceeded the Pu capacity of the commercially available resin, and also offered the advantage of sharper elution profiles, resulting in a more concentrated product, with less loss of material to the dilute heads and tails cuts. An alternate approach to improving the efficiency of this process was also explored through the development of a microchannel array system for performing the anion exchange.

  9. Electrically Switched Cesium Ion Exchange

    Energy Technology Data Exchange (ETDEWEB)

    JPH Sukamto; ML Lilga; RK Orth

    1998-10-23

    This report discusses the results of work to develop Electrically Switched Ion Exchange (ESIX) for separations of ions from waste streams relevant to DOE site clean-up. ESIX combines ion exchange and electrochemistry to provide a selective, reversible method for radionuclide separation that lowers costs and minimizes secondary waste generation typically associated with conventional ion exchange. In the ESIX process, an electroactive ion exchange film is deposited onto. a high surface area electrode, and ion uptake and elution are controlled directly by modulating the potential of the film. As a result, the production of secondary waste is minimized, since the large volumes of solution associated with elution, wash, and regeneration cycles typical of standard ion exchange are not needed for the ESIX process. The document is presented in two parts: Part I, the Summary Report, discusses the objectives of the project, describes the ESIX concept and the approach taken, and summarizes the major results; Part II, the Technology Description, provides a technical description of the experimental procedures and in-depth discussions on modeling, case studies, and cost comparisons between ESIX and currently used technologies.

  10. Lumped-parameter models

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Liingaard, Morten

    A lumped-parameter model represents the frequency dependent soil-structure interaction of a massless foundation placed on or embedded into an unbounded soil domain. The lumped-parameter model development have been reported by (Wolf 1991b; Wolf 1991a; Wolf and Paronesso 1991; Wolf and Paronesso 1992......; Wolf 1994; Wolf 1997; Wu and Lee 2002; Wu and Lee 2004). In this technical report the the steps of establishing a lumped-parameter model are presented. Following sections are included in this report: Static and dynamic formulation (Section 1.1), Simple lumped-parameter models (Section 1.2) and Advanced...... lumped-parameter models (Section 1.3)....

  11. Bacterial exchange in household washing machines

    Directory of Open Access Journals (Sweden)

    Chris eCallewaert

    2015-12-01

    Full Text Available Household washing machines launder soiled clothes and textiles, but do not sterilize them. We investigated the microbial exchange occurring in five household washing machines. Samples from a new cotton T-shirt were laundered together with a normal laundry load. Analyses were performed on the influent water and the ingoing cotton samples, as well as the greywater and the washed cotton samples. The number of living bacteria was generally not lower in the washing machine effluent water as compared to the influent water. The laundering process caused a microbial exchange of influent water bacteria, skin- and clothes-related bacteria and biofilm-related bacteria in the washing machine. A variety of biofilm-producing bacteria were enriched in the effluent after laundering, although their presence in the cotton sample was low. Nearly all bacterial genera detected on the initial cotton sample were still present in the washed cotton samples. A selection for typical skin- and clothes-related microbial species occurred in the cotton samples after laundering. Accordingly, malodour-causing microbial species might be further distributed to other clothes. The bacteria on the ingoing textiles contributed for a large part to the microbiome found in the textiles after laundering.

  12. Bacterial Exchange in Household Washing Machines.

    Science.gov (United States)

    Callewaert, Chris; Van Nevel, Sam; Kerckhof, Frederiek-Maarten; Granitsiotis, Michael S; Boon, Nico

    2015-01-01

    Household washing machines (WMs) launder soiled clothes and textiles, but do not sterilize them. We investigated the microbial exchange occurring in five household WMs. Samples from a new cotton T-shirt were laundered together with a normal laundry load. Analyses were performed on the influent water and the ingoing cotton samples, as well as the greywater and the washed cotton samples. The number of living bacteria was generally not lower in the WM effluent water as compared to the influent water. The laundering process caused a microbial exchange of influent water bacteria, skin-, and clothes-related bacteria and biofilm-related bacteria in the WM. A variety of biofilm-producing bacteria were enriched in the effluent after laundering, although their presence in the cotton sample was low. Nearly all bacterial genera detected on the initial cotton sample were still present in the washed cotton samples. A selection for typical skin- and clothes-related microbial species occurred in the cotton samples after laundering. Accordingly, malodour-causing microbial species might be further distributed to other clothes. The bacteria on the ingoing textiles contributed for a large part to the microbiome found in the textiles after laundering.

  13. Cumulant expansions for measuring water exchange using diffusion MRI

    Science.gov (United States)

    Ning, Lipeng; Nilsson, Markus; Lasič, Samo; Westin, Carl-Fredrik; Rathi, Yogesh

    2018-02-01

    The rate of water exchange across cell membranes is a parameter of biological interest and can be measured by diffusion magnetic resonance imaging (dMRI). In this work, we investigate a stochastic model for the diffusion-and-exchange of water molecules. This model provides a general solution for the temporal evolution of dMRI signal using any type of gradient waveform, thereby generalizing the signal expressions for the Kärger model. Moreover, we also derive a general nth order cumulant expansion of the dMRI signal accounting for water exchange, which has not been explored in earlier studies. Based on this analytical expression, we compute the cumulant expansion for dMRI signals for the special case of single diffusion encoding (SDE) and double diffusion encoding (DDE) sequences. Our results provide a theoretical guideline on optimizing experimental parameters for SDE and DDE sequences, respectively. Moreover, we show that DDE signals are more sensitive to water exchange at short-time scale but provide less attenuation at long-time scale than SDE signals. Our theoretical analysis is also validated using Monte Carlo simulations on synthetic structures.

  14. Exchange Rate Forecasting Using Entropy Optimized Multivariate Wavelet Denoising Model

    Directory of Open Access Journals (Sweden)

    Kaijian He

    2014-01-01

    Full Text Available Exchange rate is one of the key variables in the international economics and international trade. Its movement constitutes one of the most important dynamic systems, characterized by nonlinear behaviors. It becomes more volatile and sensitive to increasingly diversified influencing factors with higher level of deregulation and global integration worldwide. Facing the increasingly diversified and more integrated market environment, the forecasting model in the exchange markets needs to address the individual and interdependent heterogeneity. In this paper, we propose the heterogeneous market hypothesis- (HMH- based exchange rate modeling methodology to model the micromarket structure. Then we further propose the entropy optimized wavelet-based forecasting algorithm under the proposed methodology to forecast the exchange rate movement. The multivariate wavelet denoising algorithm is used to separate and extract the underlying data components with distinct features, which are modeled with multivariate time series models of different specifications and parameters. The maximum entropy is introduced to select the best basis and model parameters to construct the most effective forecasting algorithm. Empirical studies in both Chinese and European markets have been conducted to confirm the significant performance improvement when the proposed model is tested against the benchmark models.

  15. Pervaporation with ion exchange membranes

    Energy Technology Data Exchange (ETDEWEB)

    Boeddeker, K.W.; Wenzlaff, A.

    1986-01-01

    Sorption and pervaporation of aqueous-organic solvent systems (water-ethanol; water-carboxylic acids) with commercial ion exchange membranes are compared to obtain information on polymersolvent interaction vs. coupling. Close agreement between sorption selectivity and pervaporation selectivity indicates coupling. If pervaporation is less selective than sorption, polymer-solvent interaction overtakes coupling, the limit of de-coupling being phase separation within the sorbate as signaled by a sudden increase in permeability of the lesser interacting component. As long as sorption and pervaporation operate in parallel, favoring enrichment of the same component, coupling enhances the separation effect. If pervaporation counteracts sorption, coupling is detrimental to the separation effect. Potential applications include the dehydration of pre-concentrated water-ethanol using anion exchange membranes, and the enrichment of acetic acid from dilute aqueous solution by pervaporative removal of water through cation exchange membranes.

  16. Thermo-hydraulic design of earth-air heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    De Paepe, M. [Department of Flow, Heat and Combustion Mechanics, Ghent University, Ghent (Belgium); Janssens, A. [Department of Architecture and Urbanism, Ghent University, Ghent (Belgium)

    2003-07-01

    Earth-air heat exchangers, also called ground tube heat exchangers, are an interesting technique to reduce energy consumption in a building. They can cool or heat the ventilation air, using cold or heat accumulated in the soil. Several papers have been published in which a design method is described. Most of them are based on a discretisation of the one-dimensional heat transfer problem in the tube. Three-dimensional complex models, solving conduction and moisture transport in the soil are also found. These methods are of high complexity and often not ready for use by designers. In this paper, a one-dimensional analytical method is used to analyse the influence of the design parameters of the heat exchanger on the thermo-hydraulic performance. A relation is derived for the specific pressure drop, linking thermal effectiveness with pressure drop of the air inside the tube. The relation is used to formulate a design method which can be used to determine the characteristic dimensions of the earth-air heat exchanger in such a way that optimal thermal effectiveness is reached with acceptable pressure loss. The choice of the characteristic dimensions, becomes thus independent of the soil and climatological conditions. This allows designers to choose the earth-air heat exchanger configuration with the best performance. (author)

  17. Thermo-hydraulic design of earth-air heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Paepe, M. de [Ghent University (Belgium). Department of Flow, Heat and Combustion Mechanics; Janssens, A. [Ghent University (Belgium). Department of Architecture and Urbanism

    2003-05-01

    Earth-air heat exchangers, also called ground tube heat exchangers, are an interesting technique to reduce energy consumption in a building. They can cool or heat the ventilation air, using cold or heat accumulated in the soil. Several papers have been published in which a design method is described. Most of them are based on a discretisation of the one-dimensional heat transfer problem in the tube. Three-dimensional complex models, solving conduction and moisture transport in the soil are also found. These methods are of high complexity and often not ready for use by designers. In this paper, a one-dimensional analytical method is used to analyse the influence of the design parameters of the heat exchanger on the thermo-hydraulic performance. A relation is derived for the specific pressure drop, linking thermal effectiveness with pressure drop of the air inside the tube. The relation is used to formulate a design method which can be used to determine the characteristic dimensions of the earth-air heat exchanger in such a way that optimal thermal effectiveness is reached with acceptable pressure loss. The choice of the characteristic dimensions, becomes thus independent of the soil and climatological conditions. This allows designers to choose the earth-air heat exchanger configuration with the best performance. (author)

  18. Low Cost Polymer heat Exchangers for Condensing Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Butcher, Thomas [Brookhaven National Lab. (BNL), Upton, NY (United States); Trojanowski, Rebecca [Brookhaven National Lab. (BNL), Upton, NY (United States); Wei, George [Brookhaven National Lab. (BNL), Upton, NY (United States); Worek, Michael [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-09-30

    Work in this project sought to develop a suitable design for a low cost, corrosion resistant heat exchanger as part of a high efficiency condensing boiler. Based upon the design parameters and cost analysis several geometries and material options were explored. The project also quantified and demonstrated the durability of the selected polymer/filler composite under expected operating conditions. The core material idea included a polymer matrix with fillers for thermal conductivity improvement. While the work focused on conventional heating oil, this concept could also be applicable to natural gas, low sulfur heating oil, and biodiesel- although these are considered to be less challenging environments. An extruded polymer composite heat exchanger was designed, built, and tested during this project, demonstrating technical feasibility of this corrosion-resistant material approach. In such flue gas-to-air heat exchangers, the controlling resistance to heat transfer is in the gas-side convective layer and not in the tube material. For this reason, the lower thermal conductivity polymer composite heat exchanger can achieve overall heat transfer performance comparable to a metal heat exchanger. However, with the polymer composite, the surface temperature on the gas side will be higher, leading to a lower water vapor condensation rate.

  19. Stability versus exchange: a paradox in DNA replication.

    Science.gov (United States)

    Åberg, Christoffer; Duderstadt, Karl E; van Oijen, Antoine M

    2016-06-02

    Multi-component biological machines, comprising individual proteins with specialized functions, perform a variety of essential processes in cells. Once assembled, most such complexes are considered very stable, retaining individual constituents as long as required. However, rapid and frequent exchange of individual factors in a range of critical cellular assemblies, including DNA replication machineries, DNA transcription regulators and flagellar motors, has recently been observed. The high stability of a multi-protein complex may appear mutually exclusive with rapid subunit exchange. Here, we describe a multisite competitive exchange mechanism, based on simultaneous binding of a protein to multiple low-affinity sites. It explains how a component can be stably integrated into a complex in the absence of competing factors, while able to rapidly exchange in the presence of competing proteins. We provide a mathematical model for the mechanism and give analytical expressions for the stability of a pre-formed complex, in the absence and presence of competitors. Using typical binding kinetic parameters, we show that the mechanism is operational under physically realistic conditions. Thus, high stability and rapid exchange within a complex can be reconciled and this framework can be used to rationalize previous observations, qualitatively as well as quantitatively. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  20. Understanding Groundwater and Surface Water Exchange Processes Along a Controlled Stream Using Thermal Remote Sensing and In-Situ Measurements

    Science.gov (United States)

    Varli, D.; Yilmaz, K. K.

    2016-12-01

    Effective management of water resources requires understanding and quantification of interaction between groundwater and surface water bodies. Moreover, the exchange processes have recently received increasing attention due to important influences on biogeochemical and ecological status of watersheds. In this study we investigated the exchange processes between surface water and groundwater along Kirmir stream - a controlled stream nearby Kizilcahamam, Ankara, Turkey. At the first stage, potential stream reaches where the exchange processes could occur were pinpointed using geological and geomorphological information. Then, thermal remote sensing was utilized to further narrow down the potential locations in which interaction could occur at a smaller scale. Nested piezometers were installed at identified locations to observe the variations in vertical hydraulic gradient over time. Differential discharge measurements were performed to understand the gains and losses along the stream reach. Streambed temperature measurements were taken at two different depths for a period of time using temperature loggers to calculate the vertical fluid fluxes through the streambed at various locations. Basic water quality field parameters (temperature, electrical conductivity, total dissolved solid amount, dissolved oxygen, pH and oxidation - reduction potential) were measured along the stream reach, from surface water and the piezometers as wells as from the nearby springs and wells. Chloride mass balance was performed to find the contribution of groundwater and chloride concentrations were associated with the geology of the area. This hierarchical, multi-scale methodology provided an efficient and effective way to determine the locations and the direction of groundwater and surface water exchange processes within the study area.

  1. Oscillating-Coolant Heat Exchanger

    Science.gov (United States)

    Scotti, Stephen J.; Blosser, Max L.; Camarda, Charles J.

    1992-01-01

    Devices useful in situations in which heat pipes inadequate. Conceptual oscillating-coolant heat exchanger (OCHEX) transports heat from its hotter portions to cooler portions. Heat transported by oscillation of single-phase fluid, called primary coolant, in coolant passages. No time-averaged flow in tubes, so either heat removed from end reservoirs on every cycle or heat removed indirectly by cooling sides of channels with another coolant. Devices include leading-edge cooling devices in hypersonic aircraft and "frost-free" heat exchangers. Also used in any situation in which heat pipe used and in other situations in which heat pipes not usable.

  2. CHANGES IN EXCHANGE RATE REGIMES

    Directory of Open Access Journals (Sweden)

    Carmen SANDU (TODERASCU

    2014-06-01

    Full Text Available The experience of recentyears showsthat it hasa fundamentalroleformation mechanismof the exchange rateinmacroeconomic stabilization. Global economiccrises, oil shockshave shownthe difficultyoffloatingsustainabilitybyparticipants in the system. EuropeanMonetary System, focused onconcertedfloatingcurrenciestoECU, was formedunder the conditionsin which somecountries have adoptedregional monetaryarrangements(EU countries, with suchbasescurrencyregimeshybridthat combinesspecific mechanismsto those offixedratefree floating. This paperaims to demonstratethe important role thatithasthe choice ofexchange rateregimeas abasic elementin thefoundationofmacroeconomic stabilizationinstruments. Consideredan expression of thestateof the domestic economyandinternationalcompetitiveness, the exchange rate is determined bya complex set ofexternal factorsorinternalstabilityisa prerequisite forthe crisis.

  3. Proton exchange membrane fuel cells

    CERN Document Server

    Qi, Zhigang

    2013-01-01

    Preface Proton Exchange Membrane Fuel CellsFuel CellsTypes of Fuel CellsAdvantages of Fuel CellsProton Exchange Membrane Fuel CellsMembraneCatalystCatalyst LayerGas Diffusion MediumMicroporous LayerMembrane Electrode AssemblyPlateSingle CellStackSystemCell Voltage Monitoring Module (CVM)Fuel Supply Module (FSM)Air Supply Module (ASM)Exhaust Management Module (EMM)Heat Management Module (HMM)Water Management Module (WMM)Internal Power Supply Module (IPM)Power Conditioning Module (PCM)Communications Module (COM)Controls Module (CM)SummaryThermodynamics and KineticsTheoretical EfficiencyVoltagePo

  4. [Histone variants and histone exchange].

    Science.gov (United States)

    Wu, Nan; Gui, Jian-Fang

    2006-04-01

    Histones, as the basic components of nucleosome, are essential to chromatin structure and function. To adapt to various states of chromatin, corresponding histone variants are incorporated in nucleosome, and certain modifications also occur on the variants' tails. These variants change the conformation and stability of nucleosome to facilitate transcriptional activation or deactivation, DNA repairing, heterochromatin formation, and others. During histone exchange, chromatin remodeling complex facilitates histone variant deposition into nucleosome, and different variants have diverse deposition pathways. Recently, research on histone variants is not only a new hotspot in epigenetics, but also a new annotation of "histone code". In addition, histone exchange reveals new changing mechanism of DNA-histone interaction.

  5. Social Contributions in Romania

    Directory of Open Access Journals (Sweden)

    Attila Gyorgy

    2012-12-01

    Full Text Available Social contributions have an important impact on payroll policy. Also, social contributions represent a significant budgetary revenue item which can be viewed at the edge between taxation and insurance. Social contributions in Romania experienced many changes which ended in 2008. Nowadays, they are within a long transaction period towards partial externalization of the insurance activity to privately managed funds. The aim of this paper is to analyse the homogeneity of Romanian social security public scheme using annual data extracted from 2002-2009.The main findings reveal that social contributions reached the pinnacle of diversification, being too many, some of them with a small contribution rates; fiscal reforms which reduced contribution rates advantaged employers, and state will be interested to externalize this activity as far private sector will be able to assume this responsibility and the budgetary effects are acceptable for the public finance.

  6. 77 FR 4073 - Self-Regulatory Organizations; Chicago Board Options Exchange, Incorporated; Notice of Filing and...

    Science.gov (United States)

    2012-01-26

    ... addition, other conditions may apply. For example, the Exchange may establish price check parameters that... activated and, depending on the particular version of HAL, differing price check features apply.\\11\\ Thus... acceptable tick distance parameter may be applied (i.e., the same price check features applicable to HAL2...

  7. ION-EXCHANGE PROPERTIES OF IONITES WITH VARIOUS FUNCTIONAL GROUPS

    Directory of Open Access Journals (Sweden)

    Manhur Jafarli

    2016-12-01

    Full Text Available Sorption regularities of Zn2+ and Pb2+ ions from water solutions by ion exchangers of Diaion CR 11, Amberlite IRC 748 with iminodiacetic acid functional group and Dowex M 4195 with bis-picolilamine functional group are investigated, sorption isotherms are plotted, isotherms are analyzed on the basis of known models, thermodynamic parameters are calculated on the basis of kinetic data, thermodynamic factor controlling processes is determined.

  8. Learning as Social Exchange in City Year London

    DEFF Research Database (Denmark)

    Revsbech, Christine

    Learning as Social Exchange in City Year London: Action towards an image of greatness contributes to the growing field of research on social entrepreneurship. The thesis is the result of an interesting, anthropological study of a social voluntary organisation, City Year London, a British affiliate...... of an American charity. Young volunteers were followed in their daily activities working as mentors for public primary school children, and the interaction between staff and volunteers in City Year London were observed. Also, interviews with both volunteers and staff were carried out. The thesis explores...... the empirical findings applying an understanding of learning as social exchange of value. The rich empirical data has led to analyses that draw on and contribute to economic anthropology, learning theories and social entrepreneurship....

  9. John Locke's seed lists: a case study in botanical exchange.

    Science.gov (United States)

    Harris, Stephen A; Anstey, Peter R

    2009-12-01

    This paper gives a detailed analysis of four seed lists in the journals of John Locke. These lists provide a window into a fascinating open network of botanical exchange in the early 1680s which included two of the leading botanists of the day, Pierre Magnol of Montpellier and Jacob Bobart the Younger of Oxford. The provenance and significance of the lists are assessed in relation to the relevant extant herbaria and plant catalogues from the period. The lists and associated correspondence provide the main evidence for Locke's own important, though modest contribution to early modern botany, a contribution which he would have regarded as a small part of the broader project of constructing a natural history of plants. They also provide a detailed case study of the sort of open and informal network of knowledge exchange in the early modern period that is widely recognised by historians of science, but all too rarely illustrated.

  10. Estimation and optimization of heat transfer and overall presure drop for a shell and tube heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Bala Bhaskara [Dept. of Mechanical Engineering, SISTAM College, JNTU, Kakinada (India); Raju, V. Ramachandra [Dept. of Mechanical Engineering, JNTU, Kakinada (India); Deepak, B. B V. L. [Dept. of Industrial Design, National Institute of Technology, Rourkela (India)

    2017-01-15

    Most thermal/chemical industries are equipped with heat exchangers to enhance thermal efficiency. The performance of heat exchangers highly depends on design modifications in the tube side, such as the cross-sectional area, orientation, and baffle cut of the tube. However, these parameters do not exhibit a specific relation to determining the optimum design condition for shell and tube heat exchangers with a maximum heat transfer rate and reduced pressure drops. Accordingly, experimental and numerical simulations are performed for a heat exchanger with varying tube geometries. The heat exchanger considered in this investigation is a single-shell, multiple-pass device. A Generalized regression neural network (GRNN) is applied to generate a relation among the input and output process parameters for the experimental data sets. Then, an Artificial immune system (AIS) is used with GRNN to obtain optimized input parameters. Lastly, results are presented for the developed hybrid GRNN-AIS approach.

  11. Microchannel Heat Exchangers with Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Y.; Ohadi, M.M.; Radermacher, R.

    2001-09-15

    The objective of the present study was to determine the performance of CO{sub 2} microchannel evaporators and gas coolers in operational conditions representing those of residential heat pumps. A set of breadboard prototype microchannel evaporators and gas coolers was developed and tested. The refrigerant in the heat exchangers followed a counter cross-flow path with respect to the airflow direction. The test conditions corresponded to the typical operating conditions of residential heat pumps. In addition, a second set of commercial microchannel evaporators and gas coolers was tested for a less comprehensive range of operating conditions. The test results were reduced and a comprehensive data analysis, including comparison with the previous studies in this field, was performed. Capacity and pressure drop of the evaporator and gas cooler for the range of parameters studied were analyzed and are documented in this report. A gas cooler performance prediction model based on non-dimensional parameters was also developed and results are discussed as well. In addition, in the present study, experiments were conducted to evaluate capacities and pressure drops for sub-critical CO{sub 2} flow boiling and transcritical CO{sub 2} gas cooling in microchannel heat exchangers. An extensive review of the literature failed to indicate any previous systematic study in this area, suggesting a lack of fundamental understanding of the phenomena and a lack of comprehensive data that would quantify the performance potential of CO{sub 2} microchannel heat exchangers for the application at hand. All experimental tests were successfully conducted with an energy balance within {+-}3%. The only exceptions to this were experiments at very low saturation temperatures (-23 C), where energy balances were as high as 10%. In the case of evaporators, it was found that a lower saturation temperature (especially when moisture condensation occurs) improves the overall heat transfer coefficient

  12. Simulated annealing technique to design minimum cost exchanger

    Directory of Open Access Journals (Sweden)

    Khalfe Nadeem M.

    2011-01-01

    Full Text Available Owing to the wide utilization of heat exchangers in industrial processes, their cost minimization is an important target for both designers and users. Traditional design approaches are based on iterative procedures which gradually change the design and geometric parameters to satisfy a given heat duty and constraints. Although well proven, this kind of approach is time consuming and may not lead to cost effective design as no cost criteria are explicitly accounted for. The present study explores the use of nontraditional optimization technique: called simulated annealing (SA, for design optimization of shell and tube heat exchangers from economic point of view. The optimization procedure involves the selection of the major geometric parameters such as tube diameters, tube length, baffle spacing, number of tube passes, tube layout, type of head, baffle cut etc and minimization of total annual cost is considered as design target. The presented simulated annealing technique is simple in concept, few in parameters and easy for implementations. Furthermore, the SA algorithm explores the good quality solutions quickly, giving the designer more degrees of freedom in the final choice with respect to traditional methods. The methodology takes into account the geometric and operational constraints typically recommended by design codes. Three different case studies are presented to demonstrate the effectiveness and accuracy of proposed algorithm. The SA approach is able to reduce the total cost of heat exchanger as compare to cost obtained by previously reported GA approach.

  13. Exchange asymmetry in experimental settings

    Science.gov (United States)

    Thomas C. Brown; Mark D. Morrison; Jacob A. Benfield; Gretchen Nurse Rainbolt; Paul A. Bell

    2015-01-01

    We review past trading experiments and present 11 new experiments designed to show how the trading rate responds to alterations of the experimental procedure. In agreement with earlier studies, results show that if the trade decision is converted to one resembling a choice between goods the exchange asymmetry disappears, but otherwise the asymmetry is...

  14. SPECTRAL ANALYSIS OF EXCHANGE RATES

    Directory of Open Access Journals (Sweden)

    ALEŠA LOTRIČ DOLINAR

    2013-06-01

    Full Text Available Using spectral analysis is very common in technical areas but rather unusual in economics and finance, where ARIMA and GARCH modeling are much more in use. To show that spectral analysis can be useful in determining hidden periodic components for high-frequency finance data as well, we use the example of foreign exchange rates

  15. Milk fouling in heat exchangers

    NARCIS (Netherlands)

    Jeurnink, T.J.M.

    1996-01-01


    The mechanisms of fouling of heat exchangers by milk were studied. Two major fouling mechanisms were indentified during the heat treatment of milk: (i) the formation and the subsequent deposition of activated serum protein molecules as a result of the heat denaturation; (ii) the

  16. Update of telephone exchange switches

    CERN Multimedia

    2004-01-01

    Within the scope of the CERN phone services improvement, a software update will be done on exchange switches on Wednesday 27 october from 7.00 pm to 12.00 pm. Disturbances or even interruptions of telephony services may occur during this intervention. We appology in advance for any inconveniences that may occur.

  17. Maintenance of CERN telephone exchanges

    CERN Multimedia

    2005-01-01

    A maintenance of CERN telephone exchanges will be performed on 21st, 22nd, 23rd, 24th of September from 7 p.m. to 9 p.m. Disturbances or even interruptions of telephony services may occur during this lapse of time. We apology in advance for any inconveniences that this may cause.

  18. The Commodity and its Exchange

    DEFF Research Database (Denmark)

    Høst, Jeppe Engset

    2015-01-01

    and the value of the quota are examined through the concrete exchange of fishing rights, and it is explained why quota trade can give rise to speculation and monopolies. In the final part of the chapter, it is argued that the value of transferable fishing quotas rely on a social relation between owners...... and nonowners of quota, as a form of monopoly rent....

  19. Baltic Exchange teper v Tallinne

    Index Scriptorium Estoniae

    2007-01-01

    Viimane osa merekonteineritesse kokkupakitud Londoni laevandus- ja merebörsi Baltic Exchange'i endise peakorteri detailidest jõudis 2007. a. juunis Tallinna. Hoone detailid ostnud ärimehed Heiti Hääl ja Eerik-Niiles Kross plaanivad leida hoonele koha Tallinna kesklinnas. E.-N. Krossi kommentaar

  20. Energy Exchange NASA Opening Plenary

    Science.gov (United States)

    Marrs, Rick

    2017-01-01

    Rick Marrs, Deputy Assistant Administrator Office of Strategic Infrastructure NASA Headquarters will be speaking during the 2017 Energy Exchange opening plenary. His presentation showcases the NASA mission, sustainability at NASA, NASA's strategic Sustainability Performance Plan, Existing PV Partnerships, and NASA funded Solar Initiatives at KSC.

  1. Homans on Exchange: Hedonism Revived

    Science.gov (United States)

    Abrahamsson, Bengt

    1970-01-01

    George C. Homan's theory on social exchange is critically examined and found to have serious shortcomings with regard to its deductive and inductive aspects. An expecially prominent shortcoming concerns the tautological character of his concept of reward," which makes his theory deductively unclear and empirically untestable. Homan's critique…

  2. Common knowledge in email exchanges

    NARCIS (Netherlands)

    Sietsma, F.; Apt, K.R.; van Eijck, D.J.N.; Verbrugge, R.

    2011-01-01

    We consider a framework in which a group of agents communicates by means of emails, with the possibility of replies, forwards and blind carbon copies (BCC). We study the epistemic consequences of such email exchanges by introducing an appropriate epistemic language and semantics. This allows us to

  3. Knowledge Exchange with Sistema Scotland

    Science.gov (United States)

    Allan, Julie; Moran, Nikki; Duffy, Celia; Loening, Gica

    2010-01-01

    This paper reports on a knowledge exchange project, funded by the Scottish Funding Council and undertaken by a group of researchers from three higher education institutions in Scotland and the project partner, Sistema Scotland. This newly established charity is attempting to implement a major programme of social change, developed in Venezuela,…

  4. Inflationary trispectrum from graviton exchange

    DEFF Research Database (Denmark)

    Seery, David; Sloth, Martin Snoager; Vernizzi, Filippo

    2009-01-01

    We compute the connected four-point correlation function of the primordial curvature perturbation generated during inflation with standard kinetic terms, where the correlation is established via exchange of a graviton between two pairs of scalar fluctuations. Any such correlation yields a contrib...

  5. A Comprehensive Analysis of Parameter Sensitivity and Land Surface Model Optimization for the Amazon Basin

    Science.gov (United States)

    Rosolem, R.; Shuttleworth, W. J.; Gupta, H. V.; Goncalves, L.; Zeng, X.; Restrepo-Coupe, N.

    2010-12-01

    About eight years of data (1999-2006) collected from a variety of sites located in the Amazon basin under the Large-scale Biosphere-Atmosphere experiment in Amazonia (LBA) are now being used to compare a large number of land surface parameterization (LSP) schemes as part of the LBA Data-Model Intercomparison Project (LBA-DMIP). We use continuous hourly meteorological data obtained from the LBA-DMIP to drive the third generation of the Simple Biosphere model (SiB3), and to conduct a comprehensive parameter estimation study in the region. The validation data comprise of sensible and latent heat flux densities (i.e., H and LE, respectively) and Net Ecosystem Exchange of CO2 (i.e., NEE). Given the large number of parameters found in current LSP schemes (such as SiB3), manual calibration can be intractable and, consequently, automatic calibration techniques have become the preferred alternative. Parameter sensitivity analysis contributes to the understanding of potential structural characteristics of a model, and also reduces the dimension of the optimization problem by fixing insensitive parameters to their nominal values. In this study, we use the variance-based Sobol sensitivity analysis approach which determines the sensitivity of each parameter based on its percent contribution to the total output variance in the model. We then conduct the optimization of the most significant parameters in SiB3 using the so called “A Multi-Algorithm, Genetically Adaptive Multiobjective” (AMALGAM) which combines two highly desired concepts in evolutionary algorithms: (1) simultaneous multimethod search, and (2) self-adaptive offspring creation. The ultimate goal of this study is to identify key parameters related to individual LBA sites that need to be properly analyzed and calibrated in order to improve simulated land surface processes in the region. We anticipate that this will also help how measurements of these parameters are obtained in situ. The performance of SiB3 prior

  6. Air-side performance evaluation of three types of heat exchangers in dry, wet and periodic frosting conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ping [Zhejiang Vocational College of Commerce, Hangzhou, Binwen Road 470 (China); Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign 1206 West Green Street, Urbana, IL 61801 (United States); Hrnjak, P.S. [Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign 1206 West Green Street, Urbana, IL 61801 (United States)

    2009-08-15

    The performances of three types of heat exchangers that use the louver fin geometry: (1) parallel flow parallel fin with extruded flat tubes heat exchanger (PF{sup 2}), (2) parallel flow serpentine fin with extruded flat tubes heat exchanger (PFSF) and (3) round tube wave plate fin heat exchanger (RTPF) have been experimentally studied under dry, wet and frost conditions and results are presented. The parameters quantified include air-side pressure drop, water retention on the surface of the heat exchanger, capacity and overall heat transfer coefficient for air face velocity 0.9, 2 and 3 m/s, air humidity 70% and 80% and different orientations. The performances of three types of heat exchanger are compared and the results obtained are presented. The condensate drainage behavior of the air-side surface of these three heat exchanger types was studied using both the dip testing method and wind tunnel experiment. (author)

  7. On the Large Synchronous Machine Parameters Calculatioin

    Directory of Open Access Journals (Sweden)

    Ioan Adrian Viorel

    2004-01-01

    Full Text Available The large synchronous generators were intensively studied, but not so many papers are entirely dedicated to the analythical calculation of the generator´s parameters. Therefore any contribution should be welcomed if it offers an improvement in the existing procedures or formulae. The paper is dealing with the large synchronous generator smagnetizing and leakage inductances calculation. A coherent algorithm is presented and the calculated parameters for a generator are given.

  8. HECDOR: a heat exchanger cost and design optimization routine

    Energy Technology Data Exchange (ETDEWEB)

    Turner, S.E.; Madsen, W.W.

    1977-04-01

    An update is presented on a series of four computer codes developed by the Bureau of Mines. The programs were developed to evaluate design parameters and cost of heat exchangers. The major differences in three of the programs were concerned with pumping costs; the first (N = 1) used both fluids, the second (N = 2) used tube side fluid, and the third (N = 3) used shell side fluid as a base for prime parameters. All three assumed no change in phase. The fourth program (N = 4) assumed a change of phase on the shell side.

  9. The computational optimization of heat exchange efficiency in stack chimneys

    Energy Technology Data Exchange (ETDEWEB)

    Van Goch, T.A.J.

    2012-02-15

    For many industrial processes, the chimney is the final step before hot fumes, with high thermal energy content, are discharged into the atmosphere. Tapping into this energy and utilizing it for heating or cooling applications, could improve sustainability, efficiency and/or reduce operational costs. Alternatively, an unused chimney, like the monumental chimney at the Eindhoven University of Technology, could serve as an 'energy channeler' once more; it can enhance free cooling by exploiting the stack effect. This study aims to identify design parameters that influence annual heat exchange in such stack chimney applications and optimize these parameters for specific scenarios to maximize the performance. Performance is defined by annual heat exchange, system efficiency and costs. The energy required for the water pump as compared to the energy exchanged, defines the system efficiency, which is expressed in an efficiency coefficient (EC). This study is an example of applying building performance simulation (BPS) tools for decision support in the early phase of the design process. In this study, BPS tools are used to provide design guidance, performance evaluation and optimization. A general method for optimization of simulation models will be studied, and applied in two case studies with different applications (heating/cooling), namely; (1) CERES case: 'Eindhoven University of Technology monumental stack chimney equipped with a heat exchanger, rejects heat to load the cold source of the aquifer system on the campus of the university and/or provides free cooling to the CERES building'; and (2) Industrial case: 'Heat exchanger in an industrial stack chimney, which recoups heat for use in e.g. absorption cooling'. The main research question, addressing the concerns of both cases, is expressed as follows: 'what is the optimal set of design parameters so heat exchange in stack chimneys is optimized annually for the cases in which a

  10. Application of Parametrized Post-Newtonian Methods to the Gravitational IS of Satellite Energy Exchange Data

    Science.gov (United States)

    Smalley, Larry L.

    1998-01-01

    Project Satellite Energy Exchange (SEE) is a free-flying, high altitude satellite that utilizes space to construct a passive, low-temperature, nano-g environment in order to accurately measure the poorly known gravitational constant G plus other gravitational parameters that are difficult to measure in an earth-based laboratory. Eventually data received from SEE must be analyzed using a model of the gravitational interaction including parameters that describe deviations from general relativity and experiment. One model that can be used to fit tile data is the Parametrized post- Newtonian (PPN) approximation of general relativity (GR) which introduces ten parameters which have specified values in (GR). It is the lowest-order, consistent approximation that contains non linear terms. General relativity predicts that the Robertson parameters, gamma (light deflection), and beta (advance of the perihelion), are both 1 in GR. Another eight parameters, alpha(sub k), k=1,2,3 and zeta(sub k), k=1,2,3,4 and Xi are all zero in GR. Non zero values for alpha(sub k) parameters predict preferred frame effects; for zeta(sub k) violations of globally conserved quantities such as mass, momentum and angular momentum; and for Xi a contribution from the Whitehead theory of gravitation, once thought to be equivalent to GR. In addition, there is the possibility that there may be a preferred frame for the universe. If such a frame exists, then all observers must measure the velocity omega of their motion with respect to this universal rest frame. Such a frame is somewhat reminiscent of the concept of the ether which was supposedly the frame in which the velocity of light took the value c predicted by special relativity. The SEE mission can also look for deviations from the r(exp -2) law of Newtonian gravity, adding parameters alpha and lamda for non Newtonian behavior that describe the magnitude and range of the r(exp -2) deviations respectively. The foundations of the GR supposedly agree

  11. Ethical Leadership and Leader Member Exchange (LMX) Theory

    OpenAIRE

    Babič Šejla

    2014-01-01

    The aim of this paper is to evaluate the contribution that developments in the area of ethical leadership and trust have made to our understanding of effective people management within organisations. This paper is based on a case study from Harvard Business Review (2007) called "IBM - Leading the Turnaround". The author will use Leader Member Exchange (LMX) theory by Graen and Uhl-Bien (1995) and integrate the ideas of ethical leadership to critically evaluate the leadership style of the CEO ...

  12. NACP VPRM NEE Parameters Optimized to North American Flux Tower Sites, 2000-2006

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides Vegetation Photosynthesis Respiration Model (VPRM) net ecosystem exchange (NEE) parameter values optimized to 65 flux tower sites across North...

  13. Exchange Rate Expectations and the Current Exchange Rate: A Test of the Monetarist Approach

    OpenAIRE

    V S Somanath

    1984-01-01

    The monetarist model of the exchange rate includes expectations of the future exchange rate as a determinant of the current exchange rate. This paper investigates whether expectations are a significant determinant of the exchange rate. An expectations process that is consistent with a basic monetarist exchange rate model is considered. Alternative measures of expectations are generated using this process. In the empirical tests, while the standard forward exchange premium measure of expectati...

  14. Procedure to reduce sulphite in wine with anion-exchange resin

    Directory of Open Access Journals (Sweden)

    Miroslav Horák

    2012-01-01

    Full Text Available The aim of this experiment was to eliminate SO2 ions present in wine using the anion-exchanger resins. To compare the effectiveness, 2 following strongly basic anion-exchange resin were used. When activated, the sodium bicarbonate solution (activation solution I is used to prevent parallel reduction of sulphites, tartates and malates, so the anion-exchange resins were activated in two-step activation. In the second step, it was immersed into a mixture of malic acid and tartaric acid (1:1. After the application of anex into wine, the content of total SO2 was reduced to 97–201 mg.L−1 (depending on the amount of anex added into the wine sample. According to our expectations, the variants with anion-exchange resin activated only with bicarbonate solution, the tartrates and malates were significantly reduced. If the anion-exchange resin was activated with a two-steps activation, the tartaric acid and malic acid were reduced in the range of ± 0.13 g.L−1. This phenomenon was strongly reflected at the anion-exchanger Aqua Osmotic 02. The changes in antioxidant content were not affected by the type of anion-exchange resin, the method of activation, or an amount of used anion-exchanger. The color parameters of wine, expressed by the L * a * b *, were not significantly affected by the effects of anion-exchange resin use.

  15. Foreign Exchange Reserves: Bangladesh Perspective

    Directory of Open Access Journals (Sweden)

    Md Zahangir Alam

    2013-10-01

    Full Text Available This study is about foreign exchangereserves of Bangladesh. The mainpurpose of this study is to the influence of exchange rates on foreign exchangereserves to the Bangladesh context.  Both the primary and secondary data has been used inthis study. The primary data has been collected through a structuredquestionnaire from 50 respondents. The secondary data, namely Bangladeshforeign exchange reserves (FER, Bangladesh current account balance (CAB,Bangladesh capital andfinancial account balance (CFAB, and BDT/USD exchange rates (ER.  This study covers yearly data from July 01,1996 to June 30, 2005 and quarterly data from July 01, 2005 to June 30, 2012. Findingsof this study shows that out of the selected 16 factors affecting foreignexchange reserves, exchange rates occupy the first position, weighted averagescore (WAS being 4.56. Foreign exchange reserves (FER and current accountbalance (CAB have increased by 502.9087% and 1451.218%,whereas capital and financial account (CFAB has decreased by -649.024% on June30, 2012 compared to June 30, 1997. The influence of other factors heldconstant, as ER changes by 285.6894 units due to one unit change in FER, onaverage in the same direction which represents that ER has positive effect on theFER and this relationship is statistically significant.  62.1526 percentof the variation in FER is explained by ER. The outcomes of Breusch-Godfrey test (LM test, ARCHtest, and the Normality test are that there is a serial correlation among residuals, the variance of residuals is notconstant, and the residuals are not normally distributed.

  16. Compact Ceramic Microchannel Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Lewinsohn, Charles [Ceramatec, Inc., Salt Lake City, UT (United States)

    2016-10-31

    The objective of the proposed work was to demonstrate the feasibility of a step change in power plant efficiency at a commercially viable cost, by obtaining performance data for prototype, compact, ceramic microchannel heat exchangers. By performing the tasks described in the initial proposal, all of the milestones were met. The work performed will advance the technology from Technology Readiness Level 3 (TRL 3) to Technology Readiness Level 4 (TRL 4) and validate the potential of using these heat exchangers for enabling high efficiency solid oxide fuel cell (SOFC) or high-temperature turbine-based power plants. The attached report will describe how this objective was met. In collaboration with The Colorado School of Mines (CSM), specifications were developed for a high temperature heat exchanger for three commercial microturbines. Microturbines were selected because they are a more mature commercial technology than SOFC, they are a low-volume and high-value target for market entry of high-temperature heat exchangers, and they are essentially scaled-down versions of turbines used in utility-scale power plants. Using these specifications, microchannel dimensions were selected to meet the performance requirements. Ceramic plates were fabricated with microchannels of these dimensions. The plates were tested at room temperature and elevated temperature. Plates were joined together to make modular, heat exchanger stacks that were tested at a variety of temperatures and flow rates. Although gas flow rates equivalent to those in microturbines could not be achieved in the laboratory environment, the results showed expected efficiencies, robust operation under significant temperature gradients at high temperature, and the ability to cycle the stacks. Details of the methods and results are presented in this final report.

  17. Hubungan Leader-member Exchange Dan Komitmen Organisasional: Studi Pada Karyawan Restoran D'cost Seafood Surabaya

    OpenAIRE

    Taupan, Fenny; Sunyoto, Caroline; Kartika, Endo Wijaya

    2016-01-01

    Leader-member Exchange merupakan kualitas hubungan timbal Balik antara pemimpin dan karyawan dalam sebuah organisasi. Dalam penelitian ini menggunakan leader-member exchange sebagai variabel yang memiliki 4 dimensi, yaitu affect, loyalty, contribution, dan professional respect. Penelitian ini bertujuan untuk mengetahui hubungan dari leader-member exchange dan komitmen organisasional karyawan di restoran D'COST Seafood Surabaya. Dengan sampel yang melibatkan 61 karyawan, hasil penelitian menun...

  18. correlations with maternal parameters

    African Journals Online (AJOL)

    hematopoietic stem cell transplant is still far fetched, studies on the haematological parameters of umbilical cord blood are in addition relatively scanty. Several reports from Nigeria have focused mainly on haematological parameters in pregnant Nigerian subjects11, l2 and in healthy newborn neonates 13 14: Reports ...

  19. RECENT CONTRIBUTIONS OF THE STATISTICAL PHYSICS IN THE RESEARCH OF BANKING, STOCK EXCHANGE AND FOREIGN EXCHANGE MARKETS

    Directory of Open Access Journals (Sweden)

    PIRVU DANIELA

    2016-04-01

    Full Text Available This paper proposes a framework for exploring the main research approaches of the financial markets, conducted in the past years by statistical physics specialists. It, also, presents the global financial developments in the last few years, as well as a review of the most important steps in the development of the physical and mathematical modelling of the socioeconomic phenomena. In this regard, we analysed research findings published in the notable international journals. Our research demonstrated that the econophysical models developed in the past few years for the description of the financial phenomena and processes do not provide satisfactory results for the construction of complete solutions able to answer the nowadays financial challenges. We believe that research instrumentation of statistical physics has developed significantly lately and the research approaches in this field should continue and should be enhanced.

  20. An Anesthesia Preinduction Checklist to Improve Information Exchange, Knowledge of Critical Information, Perception of Safety, and Possibly Perception of Teamwork in Anesthesia Teams.

    Science.gov (United States)

    Tscholl, David W; Weiss, Mona; Kolbe, Michaela; Staender, Sven; Seifert, Burkhardt; Landert, Daniel; Grande, Bastian; Spahn, Donat R; Noethiger, Christoph B

    2015-10-01

    An anesthesia preinduction checklist (APIC) to be performed before anesthesia induction was introduced and evaluated with respect to 5 team-level outcomes, each being a surrogate end point for patient safety: information exchange (the percentage of checklist items exchanged by a team, out of 12 total items); knowledge of critical information (the percentage of critical information items out of 5 total items such as allergies, reported as known by the members of a team); team members' perceptions of safety (the median scores given by the members of a team on a continuous rating scale); their perception of teamwork (the median scores given by the members of a team on a continuous rating scale); and clinical performance (the percentage of completed items out of 14 required tasks, e.g., suction device checked). A prospective interventional study comparing anesthesia teams using the APIC with a control group not using the APIC was performed using a multimethod design. Trained observers rated information exchange and clinical performance during on-site observations of anesthesia inductions. After the observations, each team member indicated the critical information items they knew and their perceptions of safety and teamwork. One hundred five teams using the APIC were compared with 100 teams not doing so. The medians of the team-level outcome scores in the APIC group versus the control group were as follows: information exchange: 100% vs 33% (P perception of safety: 91% vs 84% (P perception of teamwork: 90% vs 86% (P = 0.028), and clinical performance: 93% vs 93% (P = 0.60). This study provides empirical evidence that the use of a preinduction checklist significantly improves information exchange, knowledge of critical information, and perception of safety in anesthesia teams-all parameters contributing to patient safety. There was a trend indicating improved perception of teamwork.

  1. Complex Heat Exchangers for Improved Performance

    Science.gov (United States)

    Bran, Gabriela Alejandra

    propagates along the channel. However, the sinusoidal behavior on one of the fluids does not fully translate to the other gets damped by the wall and the heat transfer coefficients that can be barely seen on the other flow. A scaling analysis and a parametric study were performed to determine the influence the different parameters on the system have on the time a heat exchanger takes to reach steady state. The results show the dependency of tst* (time a system takes to reach steady state) on the dimensionless parameters M, C, NTUh, NTUc, and Cw. t st* depends linearly on C and Cw, and it is a power function of M. It was also shown that tst* has a logarithmic dependency on NTUh and NTUc. A correlation was generated to approximate the time a system takes to reach steady state for systems where C w behavior during the system start-up was presented. In order to achieve the desired outlet steam temperature at a reasonable time, the system must operate at high gas mass flow rates. If the inlet temperature of the gas suffers a step change, it affects the reaction rate as well as the outlet steam temperature. A small perturbation on the gas mass flow rate has an effect on the profile shape. However, the maximum temperature reached by the gas due to reaction is not affected, and consequently, it has little effect on the steam temperature. Axial conduction in the reactor heat exchanger was also investigated, specifically in the gas section. Axial conduction cannot be assumed to be negligible in the reactor heat exchanger because of the iron-based catalytic bed. Results in this section show that axial conduction is detrimental for the system. It was found that for Peclet number greater than 100, axial conduction can be neglected. An alternative solution to address axial conduction was proposed, namely to include a well-insulated non-reacting section (without a catalytic bed) upstream of the reactor. The modified reactor heat exchanger was a novel solution to avoid the negative effect

  2. Virtual lesion extension : a measure to quantify the effects of bacterial blight on rice leaf CO2 exchange

    NARCIS (Netherlands)

    Elings, A.; Rossing, W.A.H.; Werf, van der W.

    1999-01-01

    Virtual lesion extension was proposed as a measure to summarize the effects of foliar diseases with single spreading lesions on CO2-exchange parameters at the whole-leaf level. Visible lesion plus virtual lesion extension constitute a virtual lesion, in which CO2 exchange was postulated to be nil.

  3. Notes on exchange interactions in holographic p-adic CFT

    Directory of Open Access Journals (Sweden)

    Parikshit Dutta

    2017-10-01

    Full Text Available There is a renewed interest in conformal field theories (CFT on ultrametric spaces (p-adic field and its algebraic extensions in view of their natural adaptability to the holographic setting. We compute the contributions from the exchange interactions arising from bulk trivalent vertices to the four-point correlator of the CFT using Witten diagrams with three-scalar interaction vertex. Together with the contributions from the bulk four-point interaction, i.e. the contact term, computed earlier, these provide a complete answer. We remark on the singularity structure in Mellin space, and argue that all these models are analogues of adS2/CFT1.

  4. Comparative field performance of three different gas exchange systems

    Directory of Open Access Journals (Sweden)

    G. F. Midgley

    1997-12-01

    Full Text Available We compared portable and continuously monitoring gas exchange systems under field conditions, using Protea glabra Thunb. as a test species. The aim was to determine if the same patterns of gas exchange and ancillary parameters could be obtained with rather different measurement systems, and whether the same interpretation and conclusions about environmental control of gas exchange could be drawn. The following systems were compared: 1, a ‘closed’ portable 1RGA manufactured by Ll-Cor (LI-6200; 2, an ‘open’ portable porometer manufactured by Walz; and 3, a continuously monitoring minicuvette system with temperature control facility, also manufactured by Walz. All three systems yielded similar diurnal curves for CO2  uptake, although absolute flux values for the minicuvette system were lower than those obtained for the portable systems. This was likely due to stem respiration and self-shading of leaves on the shoot enclosed in the minicuvette. Differences in sampling technique between the two portable systems, primarily with regard to changes in leaf orientation, resulted in some differences in absolute values of gas fluxes and ancillary parameters such as leaf temperature and leaf to air vapour pressure difference. However, data from all three systems allowed similar interpretations to be made about the environmental dependencies of gas exchange patterns. It appears that each system has certain drawbacks associated with widely varying field conditions. A combination of portable and continuous monitoring techniques would seem to be the most powerful approach to investigating the gas exchange patterns of terrestrial plants in their natural environment.

  5. RSA-Based Password-Authenticated Key Exchange, Revisited

    Science.gov (United States)

    Shin, Seonghan; Kobara, Kazukuni; Imai, Hideki

    The RSA-based Password-Authenticated Key Exchange (PAKE) protocols have been proposed to realize both mutual authentication and generation of secure session keys where a client is sharing his/her password only with a server and the latter should generate its RSA public/private key pair (e, n), (d, n) every time due to the lack of PKI (Public-Key Infrastructures). One of the ways to avoid a special kind of off-line (so called e-residue) attacks in the RSA-based PAKE protocols is to deploy a challenge/response method by which a client verifies the relative primality of e and φ(n) interactively with a server. However, this kind of RSA-based PAKE protocols did not give any proof of the underlying challenge/response method and therefore could not specify the exact complexity of their protocols since there exists another security parameter, needed in the challenge/response method. In this paper, we first present an RSA-based PAKE (RSA-PAKE) protocol that can deploy two different challenge/response methods (denoted by Challenge/Response Method1 and Challenge/Response Method2). The main contributions of this work include: (1) Based on the number theory, we prove that the Challenge/Response Method1 and the Challenge/Response Method2 are secure against e-residue attacks for any odd prime e (2) With the security parameter for the on-line attacks, we show that the RSA-PAKE protocol is provably secure in the random oracle model where all of the off-line attacks are not more efficient than on-line dictionary attacks; and (3) By considering the Hamming weight of e and its complexity in the. RSA-PAKE protocol, we search for primes to be recommended for a practical use. We also compare the RSA-PAKE protocol with the previous ones mainly in terms of computation and communication complexities.

  6. Transmission Electron Microscope Measures Lattice Parameters

    Science.gov (United States)

    Pike, William T.

    1996-01-01

    Convergent-beam microdiffraction (CBM) in thermionic-emission transmission electron microscope (TEM) is technique for measuring lattice parameters of nanometer-sized specimens of crystalline materials. Lattice parameters determined by use of CBM accurate to within few parts in thousand. Technique developed especially for use in quantifying lattice parameters, and thus strains, in epitaxial mismatched-crystal-lattice multilayer structures in multiple-quantum-well and other advanced semiconductor electronic devices. Ability to determine strains in indivdual layers contributes to understanding of novel electronic behaviors of devices.

  7. Analysis of Heat Transfers inside Counterflow Plate Heat Exchanger Augmented by an Auxiliary Fluid Flow

    Science.gov (United States)

    Khaled, A.-R. A.

    2014-01-01

    Enhancement of heat transfers in counterflow plate heat exchanger due to presence of an intermediate auxiliary fluid flow is investigated. The intermediate auxiliary channel is supported by transverse conducting pins. The momentum and energy equations for the primary fluids are solved numerically and validated against a derived approximate analytical solution. A parametric study including the effect of the various plate heat exchanger, and auxiliary channel dimensionless parameters is conducted. Different enhancement performance indicators are computed. The various trends of parameters that can better enhance heat transfer rates above those for the conventional plate heat exchanger are identified. Large enhancement factors are obtained under fully developed flow conditions. The maximum enhancement factors can be increased by above 8.0- and 5.0-fold for the step and exponential distributions of the pins, respectively. Finally, counterflow plate heat exchangers with auxiliary fluid flows are recommended over the typical ones if these flows can be provided with the least cost. PMID:24719572

  8. Two-pion-exchange in the non-mesonic weak decay of {lambda}-hypernuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chumillas, C. [Departament d' Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos, Universitat de Barcelona, E-08028 Barcelona (Spain)], E-mail: chumi@ecm.ub.es; Garbarino, G. [Dipartimento di Fisica Teorica, Universita di Torino and INFN, Sezione di Torino, I-10125 Turin (Italy); Parreno, A.; Ramos, A. [Departament d' Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos, Universitat de Barcelona, E-08028 Barcelona (Spain)

    2007-12-06

    The non-mesonic weak decay of {lambda}-hypernuclei is studied within a one-meson-exchange potential supplemented by a chirally motivated two-pion-exchange mechanism. The effects of final state interactions on the outgoing nucleons are also taken into account. Particular attention is payed to the asymmetry of the protons emitted by polarized hypernuclei. The one-meson-exchange model describes the non-mesonic rates and the neutron-to-proton ratio satisfactorily but predicts a too large and negative asymmetry parameter. The two-pion exchange mechanism modifies the strength and sign of some decay amplitudes. As a consequence, while the rates change moderately, the asymmetry parameter is strongly affected, acquiring values that lie well within the experimental observations.

  9. Analysis of heat transfers inside counterflow plate heat exchanger augmented by an auxiliary fluid flow.

    Science.gov (United States)

    Khaled, A-R A

    2014-01-01

    Enhancement of heat transfers in counterflow plate heat exchanger due to presence of an intermediate auxiliary fluid flow is investigated. The intermediate auxiliary channel is supported by transverse conducting pins. The momentum and energy equations for the primary fluids are solved numerically and validated against a derived approximate analytical solution. A parametric study including the effect of the various plate heat exchanger, and auxiliary channel dimensionless parameters is conducted. Different enhancement performance indicators are computed. The various trends of parameters that can better enhance heat transfer rates above those for the conventional plate heat exchanger are identified. Large enhancement factors are obtained under fully developed flow conditions. The maximum enhancement factors can be increased by above 8.0- and 5.0-fold for the step and exponential distributions of the pins, respectively. Finally, counterflow plate heat exchangers with auxiliary fluid flows are recommended over the typical ones if these flows can be provided with the least cost.

  10. Development, Fabrication, and Testing of a Liquid/Liquid Microchannel Heat Exchanger for Constellation Spacecrafts

    Science.gov (United States)

    Hawkins-Reynolds, Ebony; Le, Hung; Stephan, Ryan

    2010-01-01

    Microchannel technology can be incorporated into heat exchanger designs to decrease the mass and volume of space hardware. The National Aeronautics and Space Administration at the Johnson Space Center (NASA JSC) partnered with Pacific Northwest National Laboratories (PNNL) to develop a liquid/liquid microchannel heat exchanger that has significant mass and volume savings without sacrificing thermal and pressure drop performance. PNNL designed the microchannel heat exchanger to the same performance design requirements of a conventional plate and fin liquid/liquid heat exchanger; 3 kW duty with inlet temperatures of 26 C and 4 C. Both heat exchangers were tested using the same test parameters on a test apparatus and performance data compared.

  11. Kinetics of intramolecular chemical exchange by initial growth rates of spin saturation transfer difference experiments (SSTD NMR).

    Science.gov (United States)

    Quirós, M Teresa; Angulo, Jesús; Muñoz, María Paz

    2015-06-25

    We report here the Initial Growth Rates SSTD NMR method, as a new powerful tool to obtain the kinetic parameters of intramolecular chemical exchange in challenging small organic and organometallic molecules.

  12. Modular Heat Exchanger With Integral Heat Pipe

    Science.gov (United States)

    Schreiber, Jeffrey G.

    1992-01-01

    Modular heat exchanger with integral heat pipe transports heat from source to Stirling engine. Alternative to heat exchangers depending on integrities of thousands of brazed joints, contains only 40 brazed tubes.

  13. Flexible Exchange of Farming Device Data

    DEFF Research Database (Denmark)

    Iftikhar, Nadeem; Pedersen, Torben Bach

    2011-01-01

    A new trend in the farming business is to replace conventional farming devices with computerized farming devices. Accordingly, numerous computer-based farming devices for logging, processing and exchanging data have recently been installed on moving farm machinery such as tractors. The exchange...... of data generally takes place between the devices and farming systems, mostly installed at the premises of farmers, contractors, advisory services etc. In most cases, data exchange is based on farming data exchange standards and is bi-directional. Bi-directional data exchange allows different devices...... and systems to exchange data based on a predefined set of rules. In consequence, many hand-coded data exchange solutions have been developed in the farming business. Although efforts regarding incorporating data exchange standards have been made, their actual usage so far has been limited, due to the fact...

  14. The transparency of wholesale electricity trading on the stock exchange, investigated for the example of the European Energy Exchange; Die Transparenz im boerslichen Stromgrosshandel am Beispiel der European Energy Exchange

    Energy Technology Data Exchange (ETDEWEB)

    Wrede, Viola v.

    2012-07-01

    The purpose of the present study was to make a well-founded contribution to the debate on the transparency of wholesale electricity trading on the stock exchange in Germany, while providing decision makers with a scientific basis for their actions. It was the author's intent that among whatever insights were gained on the need for transparency rules for wholesale electricity trading on the German stock exchange the study should be restricted to those that would foreseeably also apply to electricity exchanges yet to come in Germany. The EEX was used as a case example for the one reason that it was the only one in existence in Germany at the time of writing. In line with this, the study also includes suggestions for the German spot market, despite its relocation to Paris following a merger with the French trading platform operator Powernext. The study sets out with a description of the stock exchange and electricity exchange trading in general n order to familiarise the reader with the subject. This is followed by a chapter on the concept of transparency, including a discussion of the function of transparency and its role in economic theories. The study goes on to describe other commodities exchanges and elaborates a comparison with Scandinavian electricity exchanges. The last chapter identifies and discusses needs for change.

  15. Mathematical modelling of thermal and flow processes in vertical ground heat exchangers

    Directory of Open Access Journals (Sweden)

    Pater Sebastian

    2017-12-01

    Full Text Available The main task of mathematical modelling of thermal and flow processes in vertical ground heat exchanger (BHE-Borehole Heat Exchanger is to determine the unit of borehole depth heat flux obtainable or transferred during the operation of the installation. This assignment is indirectly associated with finding the circulating fluid temperature flowing out from the U-tube at a given inlet temperature of fluid in respect to other operational parameters of the installation.

  16. Nanofiltration: ion exchange system for effective surfactant removal from water solutions

    OpenAIRE

    Kowalska, I.

    2014-01-01

    A system combining nanofiltration and ion exchange for highly effective separation of anionic surfactant from water solutions was proposed. The subjects of the study were nanofiltration polyethersulfone membranes and ion-exchange resins differing in type and structure. The quality of the treated solution was affected by numerous parameters, such as quality of the feed solution, membrane cut-off, resin type, dose and the solution contact time with the resin. A properly designed purification sy...

  17. Rethinking exchange market models as optimization algorithms

    Science.gov (United States)

    Luquini, Evandro; Omar, Nizam

    2018-02-01

    The exchange market model has mainly been used to study the inequality problem. Although the human society inequality problem is very important, the exchange market models dynamics until stationary state and its capability of ranking individuals is interesting in itself. This study considers the hypothesis that the exchange market model could be understood as an optimization procedure. We present herein the implications for algorithmic optimization and also the possibility of a new family of exchange market models

  18. Latin American foreign exchange intervention - Updated

    OpenAIRE

    Da Silva, Sergio; Nunes, Mauricio

    2007-01-01

    We examine Latin American foreign exchange intervention in a framework where the exchange rate regime is endogenous and there exists an inefficient, equilibrium foreign exchange intervention bias. The model suggests that greater central bank independence is associated with lesser intervention in the foreign exchange market, and also with leaning-against-the-wind intervention. Both results are confirmed by data from 13 Latin American countries.

  19. How to stabilize the currency exchange rate

    OpenAIRE

    BLINOV, Sergey

    2016-01-01

    In 2015, many countries had to deal with the weakening of their currencies. Issues regarding exchange rate management by the Central Banks have again become the focal point of heated debate. For example, the Russian Ruble exchange rate has been fluctuating hugely. The problem now is not so much the Ruble's weakness as instability of its exchange rate, volatility. The management of the Central Bank claims that stabilization of the Ruble exchange rate is not possible though it is the respons...

  20. Heat exchanger and related methods

    Science.gov (United States)

    Turner, Terry D.; McKellar, Michael G.

    2015-12-22

    Heat exchangers include a housing having an inlet and an outlet and forming a portion of a transition chamber. A heating member may form another portion of the transition chamber. The heating member includes a first end having a first opening and a second end having a second opening larger than the first opening. Methods of conveying a fluid include supplying a first fluid into a transition chamber of a heat exchanger, supplying a second fluid into the transition chamber, and altering a state of a portion of the first fluid with the second fluid. Methods of sublimating solid particles include conveying a first fluid comprising a material in a solid state into a transition chamber, heating the material to a gaseous state by directing a second fluid through a heating member and mixing the first fluid and the second fluid.

  1. The picture exchange communication system.

    Science.gov (United States)

    Bondy, A S; Frost, L A

    1998-01-01

    The Picture Exchange Communication System (PECS) was developed as a means to teach children with autism and related developmental disabilities a rapidly acquired, self-initiating, functional communication system. Its theoretical roots combine principles from applied behavior analysis and guidelines established within the field of alternative and augmentative communication. This approach has several potential advantages relative to imitation-based strategies (both vocal and gestural) and symbol selection strategies. The system begins with the exchange of simple icons but rapidly builds "sentence" structure. The system also emphasizes developing the request function prior to developing responding to simple questions and commenting. The development of requesting with a sentence structure also permits the rapid development of attributes more traditionally taught within a receptive mode. The relationship between the introduction of PECS and various other behavioral issues (i.e., social approach and behavior management) as well as its relationship to the codevelopment of speech are reviewed.

  2. Value Appropriation in Business Exchange

    DEFF Research Database (Denmark)

    Ellegaard, Chris; Medlin, Christopher J.; Geersbro, Jens

    2014-01-01

    master the difficult balance between value creation and appropriation. This review has provided an overview of the many managerial options for value appropriation and created knowledge on the effects of the various appropriation mechanisms enabling managers to secure company rents while not jeopardizing......Purpose – Value appropriation is a central, yet neglected aspect in business exchange research. The purpose of the paper is to generate an overview of research on active value appropriation in business exchange and provide the foundation for further research into value appropriation, as well...... as some initial guidance for managers. Design/methodology/approach – Literatures investigating value appropriation were identified by the means of a systematic review of the overall management literature. Findings – The authors provide an overview and comparison of the literatures and find that they apply...

  3. High Temperature Composite Heat Exchangers

    Science.gov (United States)

    Eckel, Andrew J.; Jaskowiak, Martha H.

    2002-01-01

    High temperature composite heat exchangers are an enabling technology for a number of aeropropulsion applications. They offer the potential for mass reductions of greater than fifty percent over traditional metallics designs and enable vehicle and engine designs. Since they offer the ability to operate at significantly higher operating temperatures, they facilitate operation at reduced coolant flows and make possible temporary uncooled operation in temperature regimes, such as experienced during vehicle reentry, where traditional heat exchangers require coolant flow. This reduction in coolant requirements can translate into enhanced range or system payload. A brief review of the approaches and challengers to exploiting this important technology are presented, along with a status of recent government-funded projects.

  4. Groundwater–Surface Water Exchange

    DEFF Research Database (Denmark)

    Karan, Sachin

    The exchange of groundwater-surface water has been invetigated in the western part of Denmark. Holtum AA provides the framework for all the performed investigations. Several methods are used, primarily eld based measurements ombined with numerical models to achieve insight to the governing...... processes of interaction between groundwater and surface water. By using heat as a tracer it has been possible to use temperature directly as calibrationtargets in a groundwater and heat transport model. Thus, it is possible to use heat investigate the change in groundwater discharge in dynamic conditions...... by using simple temperature devices along a stream to delineate the areas of interest in regard to GW{SW exchange. Thus, at several locations in a stream a temperature data logger was placed in the water column and right at the streambed-water interface. By looking at the correlation of streambed...

  5. Electrically controlled cesium ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Lilga, M. [Pacific Northwest Lab., Richland, WA (United States)

    1996-10-01

    Several sites within the DOE complex (Savannah River, Idaho, Oak Ridge and Hanford) have underground storage tanks containing high-level waste resulting from nuclear engineering activities. To facilitate final disposal of the tank waste, it is advantageous to separate and concentrate the radionuclides for final immobilization in a vitrified glass matrix. This task proposes a new approach for radionuclide separation by combining ion exchange (IX) and electrochemistry to provide a selective and economic separation method.

  6. Value-Added Exchange Rates

    OpenAIRE

    Rudolfs Bems; Robert C. Johnson

    2012-01-01

    This paper updates the conceptual foundations for measuring real effective exchange rates (REERs) to allow for vertical specialization in trade. We derive a value-added REER describing how demand for the value added that a country produces changes as the price of its value added changes relative to competitors. We then compute this index for 42 countries from 1970-2009 using trade measured in value added terms and GDP deflators. There are substantial differences between value-added and conven...

  7. Exchange, phenomenology and the Self

    OpenAIRE

    Galonska, Deniece; Yener, Efe Can; Sørensen, Karen Mallya; Olesen, Tine Lautrup

    2016-01-01

    The research project aims to investigate the ‘Self’ concerning the experience of being an international exchange student. As the research approaches the three participants as unique individuals, phenomenology provided a foundation regarding the ontological stance and a method. The philosophy of phenomenology and its different interview methods will be discussed, in relation to perspectives by Edmund Husserl and Martin Heidegger, with attention aimed at the question whether or not objectiv...

  8. Review of Fractal Heat Exchangers

    OpenAIRE

    Huang, Zhiwei; Hwang, Yunho; Aute, Vikrant; Radermacher, Reinhard

    2016-01-01

    Nature has inspired many scientists and engineers to solve problems through observation and mimicry. One such example is heat transfer enhancement. The enormous natural heat and mass transfer phenomena have led engineers to seek solutions to heat transfer enhancement problems from nature. Fractal geometries are found in respiratory and vascular systems of plants and animals, such as blood vessels, human lungs, leaves, coastlines, etc. Inspired by this, fractal heat exchangers have been develo...

  9. Prison needle exchange programs work.

    Science.gov (United States)

    2004-12-01

    On 27 October 2004 the Canadian HIV/AIDS Legal Network and the Ontario Medical Association (OMA) released reports recommending that needle exchange programs (NEPs) be implemented in prisons, based on evidence that such programs promote and protect the health of both prisoners and prison staff. At the same time, the Scottish Prison Service announced that it was looking at providing such programs, and an Iranian physician reported on a pilot project in his country.

  10. Ion-exchange chromatographic protein refolding

    NARCIS (Netherlands)

    Freydell, E.; Wielen, van der L.; Eppink, M.H.M.; Ottens, M.

    2010-01-01

    The application of ion-exchange (IEX) chromatography to protein refolding (IExR) has been successfully proven, as supported by various studies using different model proteins, ion-exchange media and flow configurations. Ion-exchange refolding offers a relatively high degree of process

  11. Monetary and Exchange Rate Policy in Slovenia

    OpenAIRE

    Gonzalo Caprirolo; Vladimir Lavrac

    2003-01-01

    The paper is divided in three sections presenting some stylized facts concerning monetary and exchange rate policy framework in Slovenia. Three periods are covered: Money-based Stabilization Policy (1991-1995), Price and Real Exchange Rate Stability Dual Targeting Policy (1996-2001), and Exchange Rate Based Stabilization Policy and Accession to ERM2 (2001-).

  12. 78 FR 38203 - Refunds and Exchanges

    Science.gov (United States)

    2013-06-26

    ... Service through the manager, Payment Technology, USPS Headquarters. Subsequently, as part of this final... from the manager, Payment Technology (see 608.8.1 for address). * * * * * 9.0 Exchanges and Refunds... Not Exchangeable The following postage items cannot be exchanged: a. Adhesive stamps, unless mistakes...

  13. Cryogenic Heat Exchanger with Turbulent Flows

    Science.gov (United States)

    Amrit, Jay; Douay, Christelle; Dubois, Francis; Defresne, Gerard

    2012-01-01

    An evaporator-type cryogenic heat exchanger is designed and built for introducing fluid-solid heat exchange phenomena to undergraduates in a practical and efficient way. The heat exchanger functions at liquid nitrogen temperature and enables cooling of N[subscript 2] and He gases from room temperatures. We present first the experimental results of…

  14. The magic of knowledge exchange

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    “If you have an apple and I have an apple and we exchange these apples then you and I will still each have one apple. But if you have an idea and I have an idea and we exchange these ideas, then each of us will have two ideas”. (George Bernard Shaw). The CERN Global Network is a new, ideal place for past and present members of the CERN community to share ideas and create new links.   On 29 April, CERN’s Knowledge and Technology Transfer (KTT) Group launched the CERN Global Network, a tool whose aim is to facilitate knowledge exchanges inside and outside CERN. "Among the greatest ambassadors of knowledge are people who have been trained and educated at CERN and also at other institutes: here is where the Global Network comes into play", says Rolf Heuer, CERN Director General. “During the first phase, the Network will be open to current and former members of the CERN personnel, that is, staff, fellows, apprentices, associates, students a...

  15. DIVALENT ION EXCHANGE WITH ALKALI

    Energy Technology Data Exchange (ETDEWEB)

    Bunge, A.L.; Klein, G.; Radke, C.J.

    1980-05-01

    Exchange of hardness ions is important in enhanced oil recovery with chemical additives. In both micellar-polymer and caustic flooding processes, multivalent ions released from rock surfaces can interact with anionic surfactants, rendering them preferentially oil soluble and/or insoluble in water. Because hardness cations are sparingly soluble and precipitate in alkaline solutions, such solutions may be more efficient as surfactant flood preflushes than are softened brines. Multivalent ion precipitation may also occur in alkaline waterflooding. To permit design of such processes, this paper presents a chromatographic theory for simultaneous ion exchange with precipitation of divalent ions. Theoretical effluent histories and concentration profiles are presented for the cases of finite pulses and continuous injection of hydroxide ions into linear cores. Complete capture of the insoluble salt particles is assumed. Results are given for the case of instantaneous equilibration of the solution with the precipitate, as well for the case of complete nonequilibrium, in which the solid precipitate does not redissolve. The efficiency of alklaine preflushing is shown to depend on the exchange isotherm, initial divalent loading of the rock, injected pH and salinity, the solubility product of the precipitated salt, and pulse size. The effect of slug size on complete equilibrium removal of hardness ions is reduced efficiency with increasing size until a critical volume approximating continuous injection is reached. Increasing injected pH and salinity provides a more favorable response. Experimental data for Berea sandstone and an argillaceous sand compare favorably with the proposed theory.

  16. EXCHANGE

    Energy Technology Data Exchange (ETDEWEB)

    Boltz, J.C. (ed.)

    1993-03-01

    This report discusses the following topics on computer environments: Releasing computer software outside EG G Idaho; Ilford digital photo imager; mandatory upgrade of PC ORPS software; ORPS host computer upgrade; EROB computer users see network change; password expiration notice; big iron still has place in HPC market; handy scripts to copy and move files; more on workstation password expiration; training center course schedule for April 1993; Microsoft Word Version 5.1a- button bar; file attributes can provide you greater flexibility; constructing a personal WordPerfect dictionary; and Windows shortcuts.

  17. Forest Biophysical Parameters (SNF)

    Data.gov (United States)

    National Aeronautics and Space Administration — Biophysical parameters (DBH, NPP, biomass, bark area index, LAI, subcanopy LAI) by study site for Aspen and Spruce in the Superior National Forest, MN (SNF)

  18. Forest Biophysical Parameters (SNF)

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Biophysical parameters (DBH, NPP, biomass, bark area index, LAI, subcanopy LAI) by study site for Aspen and Spruce in the Superior National Forest, MN (SNF)

  19. Simultaneous estimation of experimental and material parameters

    CSIR Research Space (South Africa)

    Jansen van Rensburg, GJ

    2012-07-01

    Full Text Available This conference contribution focusses on the invertibility of non-ideal material tests to accurately determine material parameters. This is done by attempting to model non-ideal test cases and comparing strains as well as force history...

  20. Reassessment of safeguards parameters

    Energy Technology Data Exchange (ETDEWEB)

    Hakkila, E.A.; Richter, J.L.; Mullen, M.F.

    1994-07-01

    The International Atomic Energy Agency is reassessing the timeliness and goal quantity parameters that are used in defining safeguards approaches. This study reviews technology developments since the parameters were established in the 1970s and concludes that there is no reason to relax goal quantity or conversion time for reactor-grade plutonium relative to weapons-grade plutonium. For low-enriched uranium, especially in countries with advanced enrichment capability there may be an incentive to shorten the detection time.

  1. Analysis of Exchange Interaction and Electron Delocalization as Intramolecular Determinants of Intermolecular Electron-Transfer Kinetics.

    Science.gov (United States)

    Bominaar, E. L.; Achim, C.; Borshch, S. A.; Girerd, J.-J.; Münck, E.

    1997-08-13

    During the past decades, spectroscopic characterization of exchange interactions and electron delocalization has developed into a powerful tool for the recognition of metal clusters in metalloproteins. By contrast, the biological relevance of these interactions has received little attention thus far. This paper presents a theoretical study in which this problem is addressed. The rate constant for intermolecular electron-transfer reactions which are essential in many biological processes is investigated. An expression is derived for the dependence of the rate constant for self-exchange on the delocalization degree of the mixed-valence species. This result allows us to rationalize published kinetic data. In the simplest case of electron transfer from an exchange-coupled binuclear mixed-valence donor to a diamagnetic acceptor, the rate constant is evaluated, taking into account spin factors and exchange energies in the initial and final state. The theoretical analysis indicates that intramolecular spin-dependent electron delocalization (double exchange) and Heisenberg-Dirac-van Vleck (HDvV) exchange have an important impact on the rate constant for intermolecular electron transfer. This correlation reveals a novel relationship between magnetochemistry and electrochemistry. Contributions to the electron transfer from the ground and excited states of the exchange-coupled dimer have been evaluated. For clusters in which these states have different degrees of delocalization, the excited-state contributions to electron transfer may become dominant at potentials which are less reductive than the potential at which the rate constant for the transfer from the ground state is maximum. The rate constant shows a steep dependence on HDvV exchange, which suggests that an exchange-coupled cluster can act as a molecular switch for exchange-controlled electron gating. The relevance of this result is discussed in the context of substrate specificity of electron-transfer reactions in

  2. Numerical Calculation and Exergy Equations of Spray Heat Exchanger Attached to a Main Fan Diffuser

    Science.gov (United States)

    Cui, H.; Wang, H.; Chen, S.

    2015-04-01

    In the present study, the energy depreciation rule of spray heat exchanger, which is attached to a main fan diffuser, is analyzed based on the second law of thermodynamics. Firstly, the exergy equations of the exchanger are deduced. The equations are numerically calculated by the fourth-order Runge-Kutta method, and the exergy destruction is quantitatively effected by the exchanger structure parameters, working fluid (polluted air, i.e., PA; sprayed water, i.e., SW) initial state parameters and the ambient reference parameters. The results are showed: (1) heat transfer is given priority to latent transfer at the bottom of the exchanger, and heat transfer of convection and is equivalent to that of condensation in the upper. (2) With the decrease of initial temperature of SW droplet, the decrease of PA velocity or the ambient reference temperature, and with the increase of a SW droplet size or initial PA temperature, exergy destruction both increase. (3) The exergy efficiency of the exchanger is 72.1 %. An approach to analyze the energy potential of the exchanger may be provided for engineering designs.

  3. A Double-Edged Sword: Race, Daily Family Support Exchanges, and Daily Well-Being

    OpenAIRE

    Kelly E. Cichy; Stawski, Robert S.; Almeida, David M.

    2013-01-01

    This study contributes to research on race and family ties by exploring racial differences in the direct effects of family support exchanges on daily well-being and the extent to which family support buffers/exacerbates stressor reactivity. African Americans and European Americans aged 34 to 84 (N = 1,931) from the National Study of Daily Experiences (NSDE) reported on family support exchanges (i.e., support received/support provided), daily stressors, and negative affect du...

  4. Subjective trust, perceived risk and exchange performance in buyer-supplier relationships

    OpenAIRE

    Emanuela Delbufalo

    2012-01-01

    This article offers some theoretical and empirical contributions to the literature on relational exchange by examining the nature of subjective trust and perceived risk in buyer-supplier relationships. The relational view represents the theoretical framework for the research. The study explores the theoretical proposition that subjective trust and perceived risk in buyer-supplier relationships impact on exchange performance through the mediating effects of four sources of relational rents: as...

  5. Social Exchange and Sexual Behavior in Young Women’s Premarital Relationships in Kenya

    OpenAIRE

    Luke, Nancy; Goldberg, Rachel E.; Mberu, Blessing U.; Zulu, Eliya M.

    2011-01-01

    Transactional sex, or the exchange of money and gifts for sexual activities within nonmarital relationships, has been widely considered a contributing factor to the disproportionate prevalence of HIV/AIDS among young women in sub-Saharan Africa. This study applied social exchange theory to premarital relationships in order to investigate the linkages between a variety of young women’s resources—including employment and material transfers from male partners—and sexual behaviors. Data on the fi...

  6. Intensification of heat exchange by method of interacting flows

    Science.gov (United States)

    Agishev, B. Y.; Varava, A. N.; Dedov, A. V.; Zakharenkov, A. V.; Komov, A. T.

    2017-11-01

    The effectiveness of the heat exchange intensifier “rib-twisted wire” is considered in this paper. The main goal was to study the influence of the wire coiling step t on heat transfer and hydraulic resistance for different values \\dot{H} of the dimensionless height of the edge \\dot{H}, as well as some results on heat exchange during bubbly boiling in an annular channel. Given: • a brief description and an image of the heat exchange intensifier “rib-twisted wire” • generalized results of studies of heat exchange and hydraulic resistance in the annular channel in the single-phase convection with different geometric characteristics of the intensifier • empirical correlations of the generalized experimental results that allow to calculate the coefficient of hydraulic resistance and heat transfer in the range of regime parameters in the single-phase convection that is being studied. • some results of experiments in bubbly boiling regimes and near-critical thermal loads.

  7. Kinetic model of mass exchange with dynamic Arrhenius transition rates

    Science.gov (United States)

    Hristopulos, Dionissios T.; Muradova, Aliki

    2016-02-01

    We study a nonlinear kinetic model of mass exchange between interacting grains. The transition rates follow the Arrhenius equation with an activation energy that depends dynamically on the grain mass. We show that the activation parameter can be absorbed in the initial conditions for the grain masses, and that the total mass is conserved. We obtain numerical solutions of the coupled, nonlinear, ordinary differential equations of mass exchange for the two-grain system, and we compare them with approximate theoretical solutions in specific neighborhoods of the phase space. Using phase plane methods, we determine that the system exhibits regimes of diffusive and growth-decay (reverse diffusion) kinetics. The equilibrium states are determined by the mass equipartition and separation nullcline curves. If the transfer rates are perturbed by white noise, numerical simulations show that the system maintains the diffusive and growth-decay regimes; however, the noise can reverse the sign of equilibrium mass difference. Finally, we present theoretical analysis and numerical simulations of a system with many interacting grains. Diffusive and growth-decay regimes are established as well, but the approach to equilibrium is considerably slower. Potential applications of the mass exchange model involve coarse-graining during sintering and wealth exchange in econophysics.

  8. Classification of hydrological parameter sensitivity and evaluation of parameter transferability across 431 US MOPEX basins

    Science.gov (United States)

    Ren, Huiying; Hou, Zhangshuan; Huang, Maoyi; Bao, Jie; Sun, Yu; Tesfa, Teklu; Ruby Leung, L.

    2016-05-01

    The Community Land Model (CLM) represents physical, chemical, and biological processes of the terrestrial ecosystems that interact with climate across a range of spatial and temporal scales. As CLM includes numerous sub-models and associated parameters, the high-dimensional parameter space presents a formidable challenge for quantifying uncertainty and improving Earth system predictions needed to assess environmental changes and risks. This study aims to evaluate the potential of transferring hydrologic model parameters in CLM through sensitivity analyses and classification across watersheds from the Model Parameter Estimation Experiment (MOPEX) in the United States. The sensitivity of CLM-simulated water and energy fluxes to hydrological parameters across 431 MOPEX basins are first examined using an efficient stochastic sampling-based sensitivity analysis approach. Linear, interaction, and high-order nonlinear impacts are all identified via statistical tests and stepwise backward removal parameter screening. The basins are then classified according to their parameter sensitivity patterns (internal attributes), as well as their hydrologic indices/attributes (external hydrologic factors) separately, using Principal component analysis (PCA) and expectation-maximization (EM) - based clustering approach. Similarities and differences among the parameter sensitivity-based classification system (S-Class), the hydrologic indices-based classification (H-Class), and the Koppen climate classification systems (K-Class) are discussed. Within each parameter sensitivity-based classification system (S-Class) with similar parameter sensitivity characteristics, similar inversion modeling setups can be used for parameter calibration, and the parameters and their contribution or significance to water and energy cycling may also be more transferrable. This classification study provides guidance on identifiable parameters, and on parameterization and inverse model design for CLM but the

  9. The dielectric environment dependent exchange self-energy of the energy structure in graphene

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C.H., E-mail: chyang@nuist.edu.c [Faculty of Maths and Physics, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Xu, W. [Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2010-10-01

    We theoretically calculate the energy dispersion in the presence of the screened exchange self-energy in extrinsic monolayer graphene. It is found that the exchange self-energy enhances the renormalized Fermi velocity. With decreasing the dielectric constant, the screening effect and the electron correlation effect increase which induces the Fermi velocity increasing. The screened exchange energy has an energy shift at the Dirac points. The self-energy from the valance band carriers gives the main contribution to the effective energy. We also discuss the electron density dependence of the self-energy.

  10. Localized hydration in lyophilized myoglobin by hydrogen-deuterium exchange mass spectrometry. 2. Exchange kinetics.

    Science.gov (United States)

    Sophocleous, Andreas M; Topp, Elizabeth M

    2012-04-02

    Solid-state hydrogen-deuterium exchange with mass spectrometric analysis (ssHDX) is a promising method for characterizing proteins in amorphous solids. Though analysis of HDX kinetics is informative and well-established in solution, application of these methods to solid samples is complicated by possible heterogeneities in the solid. The studies reported here provide a detailed analysis of the kinetics of hydration and ssHDX for equine myoglobin (Mb) in solid matrices containing sucrose or mannitol. Water sorption was rapid relative to ssHDX, indicating that ssHDX kinetics was not limited by bulk water transport. Deuterium uptake in solids was well-characterized by a biexponential model; values for regression parameters provided insight into differences between the two solid matrices. Analysis of the widths of peptide mass envelopes revealed that, in solution, an apparent EX2 mechanism prevails, consistent with native conformation of the protein. In contrast, in mannitol-containing samples, a smaller non-native subpopulation exchanges by an EX1-like mechanism. Together, the results indicate that the analysis of ssHDX kinetic data and of the widths of peptide mass envelopes is useful in screening solid formulations of protein drugs for the presence of non-native species that cannot be detected by amide I FTIR.

  11. Localized Hydration in Lyophilized Myoglobin by Hydrogen-Deuterium Exchange Mass Spectrometry. 2. Exchange Kinetics

    Science.gov (United States)

    Sophocleous, Andreas M.; Topp, Elizabeth M.

    2012-01-01

    Solid-state hydrogen deuterium exchange with mass spectrometric analysis (ssHDX) is a promising method for characterizing proteins in amorphous solids. Though analysis of HDX kinetics is informative and well-established in solution, application of these methods to solid samples is complicated by possible heterogeneities in the solid. The studies reported here provide a detailed analysis of the kinetics of hydration and ssHDX for equine myoglobin (Mb) in solid matrices containing sucrose or mannitol. Water sorption was rapid relative to ssHDX, indicating that ssHDX kinetics was not limited by bulk water transport. Deuterium uptake in solids was well-characterized by a bi-exponential model; values for regression parameters provided insight into differences between the two solid matrices. Analysis of the widths of peptide mass envelopes revealed that in solution, an apparent EX2 mechanism prevails, consistent with native conformation of the protein. In contrast, in mannitol-containing samples, a smaller non-native subpopulation exchanges by an EX1-like mechanism. Together, the results indicate that the analysis of ssHDX kinetic data and the widths of peptide mass envelopes are useful in screening solid formulations of protein drugs for the presence of non-native species that cannot be detected by amide I FTIR. PMID:22352990

  12. XTC MRI: sensitivity improvement through parameter optimization.

    Science.gov (United States)

    Ruppert, Kai; Mata, Jaime F; Wang, Hsuan-Tsung J; Tobias, William A; Cates, Gordon D; Brookeman, James R; Hagspiel, Klaus D; Mugler, John P

    2007-06-01

    Xenon polarization Transfer Contrast (XTC) MRI pulse sequences permit the gas exchange of hyperpolarized xenon-129 in the lung to be measured quantitatively. However, the pulse sequence parameter values employed in previously published work were determined empirically without considering the now-known gas exchange rates and the underlying lung physiology. By using a theoretical model for the consumption of magnetization during data acquisition, the noise intensity in the computed gas-phase depolarization maps was minimized as a function of the gas-phase depolarization rate. With such optimization the theoretical model predicted an up to threefold improvement in precision. Experiments in rabbits demonstrated that for typical imaging parameter values the optimized XTC pulse sequence yielded a median noise intensity of only about 3% in the depolarization maps. Consequently, the reliable detection of variations in the average alveolar wall thickness of as little as 300 nm can be expected. This improvement in the precision of the XTC MRI technique should lead to a substantial increase in its sensitivity for detecting pathological changes in lung function.

  13. Performance evaluation on an air-cooled heat exchanger for alumina nanofluid under laminar flow.

    Science.gov (United States)

    Teng, Tun-Ping; Hung, Yi-Hsuan; Teng, Tun-Chien; Chen, Jyun-Hong

    2011-08-09

    This study analyzes the characteristics of alumina (Al2O3)/water nanofluid to determine the feasibility of its application in an air-cooled heat exchanger for heat dissipation for PEMFC or electronic chip cooling. The experimental sample was Al2O3/water nanofluid produced by the direct synthesis method at three different concentrations (0.5, 1.0, and 1.5 wt.%). The experiments in this study measured the thermal conductivity and viscosity of nanofluid with weight fractions and sample temperatures (20-60°C), and then used the nanofluid in an actual air-cooled heat exchanger to assess its heat exchange capacity and pressure drop under laminar flow. Experimental results show that the nanofluid has a higher heat exchange capacity than water, and a higher concentration of nanoparticles provides an even better ratio of the heat exchange. The maximum enhanced ratio of heat exchange and pressure drop for all the experimental parameters in this study was about 39% and 5.6%, respectively. In addition to nanoparticle concentration, the temperature and mass flow rates of the working fluid can affect the enhanced ratio of heat exchange and pressure drop of nanofluid. The cross-section aspect ratio of tube in the heat exchanger is another important factor to be taken into consideration.

  14. Fabrication and characterization planar waveguides of Na+-Ag+/K+ by ion exchange and prism coupler

    Science.gov (United States)

    Yulianto, Muchlas; Marzuki, Ahmad; Suryanti, Venty

    2017-08-01

    This paper reports about the fabrication of planar waveguides made of the ion-exchanged technique on a soda-lime glass. The process of the ion-exchanged occurs between Na+ ions from the soda-lime glass and Ag+/K+ ions from molten salt AgNO3+KNO3. Fabrication is conducted at 70 mol% of KNO3 and 30 mol% of an AgNO3 melt takes place for the realization of planar waveguides. The duration of ion-exchanged has been varied in the range of 25-900 minutes at the temperature of 350°C to diffusion processes. The purpose of our experiments is especially to study the effect of duration of the ion-exchange process to the main parameters used to characterized optical waveguides. The optical transmission spectra of the ion exchanged glasses were measured with a single beam UV/Visible Ocean Optics USB4000 Spectrometer. The refractive index change, the number of modes waveguides, and diffusion depth had been investigated. The m-lines spectroscopy with standard prism-coupling technique at 632,8 nm was used to measure the number of modes and depth of waveguides. Refractive index was measured with ABBE refractometer. The result shows that the glass refractive index change values of the ion-exchanged glasses are independent of both the ion exchange duration. The number of modes and the diffusion depth, however increase with increasing the duration of ion-exchange processes.

  15. Fault Diagnosis for the Heat Exchanger of the Aircraft Environmental Control System Based on the Strong Tracking Filter

    Science.gov (United States)

    Ma, Jian; Lu, Chen; Liu, Hongmei

    2015-01-01

    The aircraft environmental control system (ECS) is a critical aircraft system, which provides the appropriate environmental conditions to ensure the safe transport of air passengers and equipment. The functionality and reliability of ECS have received increasing attention in recent years. The heat exchanger is a particularly significant component of the ECS, because its failure decreases the system’s efficiency, which can lead to catastrophic consequences. Fault diagnosis of the heat exchanger is necessary to prevent risks. However, two problems hinder the implementation of the heat exchanger fault diagnosis in practice. First, the actual measured parameter of the heat exchanger cannot effectively reflect the fault occurrence, whereas the heat exchanger faults are usually depicted by utilizing the corresponding fault-related state parameters that cannot be measured directly. Second, both the traditional Extended Kalman Filter (EKF) and the EKF-based Double Model Filter have certain disadvantages, such as sensitivity to modeling errors and difficulties in selection of initialization values. To solve the aforementioned problems, this paper presents a fault-related parameter adaptive estimation method based on strong tracking filter (STF) and Modified Bayes classification algorithm for fault detection and failure mode classification of the heat exchanger, respectively. Heat exchanger fault simulation is conducted to generate fault data, through which the proposed methods are validated. The results demonstrate that the proposed methods are capable of providing accurate, stable, and rapid fault diagnosis of the heat exchanger. PMID:25823010

  16. Fault diagnosis for the heat exchanger of the aircraft environmental control system based on the strong tracking filter.

    Science.gov (United States)

    Ma, Jian; Lu, Chen; Liu, Hongmei

    2015-01-01

    The aircraft environmental control system (ECS) is a critical aircraft system, which provides the appropriate environmental conditions to ensure the safe transport of air passengers and equipment. The functionality and reliability of ECS have received increasing attention in recent years. The heat exchanger is a particularly significant component of the ECS, because its failure decreases the system's efficiency, which can lead to catastrophic consequences. Fault diagnosis of the heat exchanger is necessary to prevent risks. However, two problems hinder the implementation of the heat exchanger fault diagnosis in practice. First, the actual measured parameter of the heat exchanger cannot effectively reflect the fault occurrence, whereas the heat exchanger faults are usually depicted by utilizing the corresponding fault-related state parameters that cannot be measured directly. Second, both the traditional Extended Kalman Filter (EKF) and the EKF-based Double Model Filter have certain disadvantages, such as sensitivity to modeling errors and difficulties in selection of initialization values. To solve the aforementioned problems, this paper presents a fault-related parameter adaptive estimation method based on strong tracking filter (STF) and Modified Bayes classification algorithm for fault detection and failure mode classification of the heat exchanger, respectively. Heat exchanger fault simulation is conducted to generate fault data, through which the proposed methods are validated. The results demonstrate that the proposed methods are capable of providing accurate, stable, and rapid fault diagnosis of the heat exchanger.

  17. Fault diagnosis for the heat exchanger of the aircraft environmental control system based on the strong tracking filter.

    Directory of Open Access Journals (Sweden)

    Jian Ma

    Full Text Available The aircraft environmental control system (ECS is a critical aircraft system, which provides the appropriate environmental conditions to ensure the safe transport of air passengers and equipment. The functionality and reliability of ECS have received increasing attention in recent years. The heat exchanger is a particularly significant component of the ECS, because its failure decreases the system's efficiency, which can lead to catastrophic consequences. Fault diagnosis of the heat exchanger is necessary to prevent risks. However, two problems hinder the implementation of the heat exchanger fault diagnosis in practice. First, the actual measured parameter of the heat exchanger cannot effectively reflect the fault occurrence, whereas the heat exchanger faults are usually depicted by utilizing the corresponding fault-related state parameters that cannot be measured directly. Second, both the traditional Extended Kalman Filter (EKF and the EKF-based Double Model Filter have certain disadvantages, such as sensitivity to modeling errors and difficulties in selection of initialization values. To solve the aforementioned problems, this paper presents a fault-related parameter adaptive estimation method based on strong tracking filter (STF and Modified Bayes classification algorithm for fault detection and failure mode classification of the heat exchanger, respectively. Heat exchanger fault simulation is conducted to generate fault data, through which the proposed methods are validated. The results demonstrate that the proposed methods are capable of providing accurate, stable, and rapid fault diagnosis of the heat exchanger.

  18. Nucleon charge-exchange reactions at intermediate energy

    Energy Technology Data Exchange (ETDEWEB)

    Alford, W.P. [Western Ontario Univ., London, ON (Canada). Dept. of Physics]|[TRIUMF, Vancouver, BC (Canada); Spicer, B.M. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    An historical review of the development of ideas pertaining to Gamow-Teller giant resonances is given, and a description of the emergence of techniques for the study of charge exchange reactions - particularly the technical advances which yielded the recent volume of new date. The present status of charge exchange reactions is reviewed and assessed. Evidence is presented from the {sup 14}C(p,n) reaction for the dominance of the spin-isospin component of the nucleon-nucleon interaction in intermediate energy reactions. In (p,n) reactions the Gamow-Teller giant resonance dominates the spectra, with higher multipoles contributing. By contrast, in (n,p) reactions in the heavier nuclei, the Gamow-Teller transitions are substantially Pauli-blocked and the spin dipole resonance dominates, with contributions from higher multipoles. Discussions of the multipole decomposition process, used to obtain from the data the contributions of the different multipoles, and the contributions of the multipoles, are given. 226 refs., 19 figs.

  19. The determinants of exchange rate in Croatia

    Directory of Open Access Journals (Sweden)

    Manuel BENAZIC

    2016-06-01

    Full Text Available The dilemma for every country with an independent monetary policy is which kind of exchange rate arrangement should be applied. Through the exchange rate policy, countries can influence their economies, i.e. price stability and export competiveness. Croatia is a new EU member state, it has its own monetary policy and currency but it is on the way to euro introduction. Regarding the experiences from the beginning of the 1990s when Croatia was faced with serious monetary instabilities and hyperinflation, the goal of Croatian National Bank (CNB is to ensure price stability and one way to do so is through exchange rate policy. Croatia, as a small and open economy, has applied a managed floating exchange rate regime. The exchange rate is determined primarily by the foreign exchange supply and demand on the foreign exchange market, with occasional market interventions by the CNB. Therefore, in order to maintain exchange rate stability, policymakers must be able to recognize how changes in these factors affect changes in the exchange rate. This research aims to find a relationship among the main sources of foreign currency inflow and outflow and the level of exchange rate in Croatia. The analysis is carried out by using the bounds testing (ARDL approach for co-integration. The results indicate the existence of a stable co-integration relationship between the observed variables, whereby an increase in the majority of variables leads to an exchange rate appreciation.

  20. Analysis of the Na+/Ca2+ exchanger gene family within the phylum Nematoda.

    Directory of Open Access Journals (Sweden)

    Chao He

    Full Text Available Na+/Ca2+ exchangers are low affinity, high capacity transporters that rapidly transport calcium at the plasma membrane, mitochondrion, endoplasmic (and sarcoplasmic reticulum, and the nucleus. Na+/Ca2+ exchangers are widely expressed in diverse cell types where they contribute homeostatic balance to calcium levels. In animals, Na+/Ca2+ exchangers are divided into three groups based upon stoichiometry: Na+/Ca2+ exchangers (NCX, Na+/Ca2+/K+ exchangers (NCKX, and Ca2+/Cation exchangers (CCX. In mammals there are three NCX genes, five NCKX genes and one CCX (NCLX gene. The genome of the nematode Caenorhabditis elegans contains ten Na+/Ca2+ exchanger genes: three NCX; five CCX; and two NCKX genes. Here we set out to characterize structural and taxonomic specializations within the family of Na+/Ca2+ exchangers across the phylum Nematoda. In this analysis we identify Na+/Ca2+ exchanger genes from twelve species of nematodes and reconstruct their phylogenetic and evolutionary relationships. The most notable feature of the resulting phylogenies was the heterogeneous evolution observed within exchanger subtypes. Specifically, in the case of the CCX exchangers we did not detect members of this class in three Clade III nematodes. Within the Caenorhabditis and Pristionchus lineages we identify between three and five CCX representatives, whereas in other Clade V and also Clade IV nematode taxa we only observed a single CCX gene in each species, and in the Clade III nematode taxa that we sampled we identify NCX and NCKX encoding genes but no evidence of CCX representatives using our mining approach. We also provided re-annotation for predicted CCX gene structures from Heterorhabditis bacteriophora and Caenorhabditis japonica by RT-PCR and sequencing. Together, these findings reveal a complex picture of Na+/Ca2+ transporters in nematodes that suggest an incongruent evolutionary history of proteins that provide central control of calcium dynamics.

  1. Analysis of the Na+/Ca2+ exchanger gene family within the phylum Nematoda.

    Science.gov (United States)

    He, Chao; O'Halloran, Damien M

    2014-01-01

    Na+/Ca2+ exchangers are low affinity, high capacity transporters that rapidly transport calcium at the plasma membrane, mitochondrion, endoplasmic (and sarcoplasmic) reticulum, and the nucleus. Na+/Ca2+ exchangers are widely expressed in diverse cell types where they contribute homeostatic balance to calcium levels. In animals, Na+/Ca2+ exchangers are divided into three groups based upon stoichiometry: Na+/Ca2+ exchangers (NCX), Na+/Ca2+/K+ exchangers (NCKX), and Ca2+/Cation exchangers (CCX). In mammals there are three NCX genes, five NCKX genes and one CCX (NCLX) gene. The genome of the nematode Caenorhabditis elegans contains ten Na+/Ca2+ exchanger genes: three NCX; five CCX; and two NCKX genes. Here we set out to characterize structural and taxonomic specializations within the family of Na+/Ca2+ exchangers across the phylum Nematoda. In this analysis we identify Na+/Ca2+ exchanger genes from twelve species of nematodes and reconstruct their phylogenetic and evolutionary relationships. The most notable feature of the resulting phylogenies was the heterogeneous evolution observed within exchanger subtypes. Specifically, in the case of the CCX exchangers we did not detect members of this class in three Clade III nematodes. Within the Caenorhabditis and Pristionchus lineages we identify between three and five CCX representatives, whereas in other Clade V and also Clade IV nematode taxa we only observed a single CCX gene in each species, and in the Clade III nematode taxa that we sampled we identify NCX and NCKX encoding genes but no evidence of CCX representatives using our mining approach. We also provided re-annotation for predicted CCX gene structures from Heterorhabditis bacteriophora and Caenorhabditis japonica by RT-PCR and sequencing. Together, these findings reveal a complex picture of Na+/Ca2+ transporters in nematodes that suggest an incongruent evolutionary history of proteins that provide central control of calcium dynamics.

  2. Parameter estimation through ignorance.

    Science.gov (United States)

    Du, Hailiang; Smith, Leonard A

    2012-07-01

    Dynamical modeling lies at the heart of our understanding of physical systems. Its role in science is deeper than mere operational forecasting, in that it allows us to evaluate the adequacy of the mathematical structure of our models. Despite the importance of model parameters, there is no general method of parameter estimation outside linear systems. A relatively simple method of parameter estimation for nonlinear systems is introduced, based on variations in the accuracy of probability forecasts. It is illustrated on the logistic map, the Henon map, and the 12-dimensional Lorenz96 flow, and its ability to outperform linear least squares in these systems is explored at various noise levels and sampling rates. As expected, it is more effective when the forecast error distributions are non-Gaussian. The method selects parameter values by minimizing a proper, local skill score for continuous probability forecasts as a function of the parameter values. This approach is easier to implement in practice than alternative nonlinear methods based on the geometry of attractors or the ability of the model to shadow the observations. Direct measures of inadequacy in the model, the "implied ignorance," and the information deficit are introduced.

  3. A Review of Industrial Heat Exchange Optimization

    Science.gov (United States)

    Yao, Junjie

    2018-01-01

    Heat exchanger is an energy exchange equipment, it transfers the heat from a working medium to another working medium, which has been wildly used in petrochemical industry, HVAC refrigeration, aerospace and so many other fields. The optimal design and efficient operation of the heat exchanger and heat transfer network are of great significance to the process industry to realize energy conservation, production cost reduction and energy consumption reduction. In this paper, the optimization of heat exchanger, optimal algorithm and heat exchanger optimization with different objective functions are discussed. Then, optimization of the heat exchanger and the heat exchanger network considering different conditions are compared and analysed. Finally, all the problems discussed are summarized and foresights are proposed.

  4. Creating sustainable local health information exchanges: can barriers to stakeholder participation be overcome?

    Science.gov (United States)

    Grossman, Joy M; Kushner, Kathryn L; November, Elizabeth A

    2008-02-01

    Local health information exchanges (HIEs) hold the promise of collecting patient clinical data across sites of care to provide more complete and timely information for treatment, as well as supporting quality improvement and reporting, public health activities, and clinical research. Findings from a study of stakeholder perspectives on participation in four HIEs by the Center for Studying Health System Change (HSC) and the National Institute for Health Care Management (NIHCM) Foundation suggest, however, that barriers to achieving data exchange remain high. Concerns about loss of competitive advantage and data misuse impede provider and health plan willingness to contribute patient data. Additionally, uncertainty about who benefits from HIEs is affecting stakeholder willingness to fund the exchanges. The more mature exchanges--Cincinnati-based HealthBridge and the Indiana Health Information Exchange (IHIE)--have achieved some viability by meeting a specific business need--more efficient delivery of hospital test results to physicians. The newer exchanges--CareSpark, serving northeast Tennessee and southwest Virginia, and the Tampa Bay Regional Health Information Organization (RHIO)--have struggled to identify and finance initial services without a similar critical mass of hospital participation. While narrow data exchange efforts that improve transaction efficiency may be a pragmatic first step to overcome barriers to stakeholder participation, expanding HIEs to achieve the broad-based data exchange necessary for quality reporting and pay-for-performance (P4P) activities raises more challenges.

  5. Dissecting the accountability of parameterized and parameter-free single-hybrid and double-hybrid functionals for photophysical properties of TADF-based OLEDs

    Science.gov (United States)

    Alipour, Mojtaba; Karimi, Niloofar

    2017-06-01

    Organic light emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) emitters are an attractive category of materials that have witnessed a booming development in recent years. In the present contribution, we scrutinize the accountability of parameterized and parameter-free single-hybrid (SH) and double-hybrid (DH) functionals through the two formalisms, full time-dependent density functional theory (TD-DFT) and Tamm-Dancoff approximation (TDA), for the estimation of photophysical properties like absorption energy, emission energy, zero-zero transition energy, and singlet-triplet energy splitting of TADF molecules. According to our detailed analyses on the performance of SHs based on TD-DFT and TDA, the TDA-based parameter-free SH functionals, PBE0 and TPSS0, with one-third of exact-like exchange turned out to be the best performers in comparison to other functionals from various rungs to reproduce the experimental data of the benchmarked set. Such affordable SH approximations can thus be employed to predict and design the TADF molecules with low singlet-triplet energy gaps for OLED applications. From another perspective, considering this point that both the nonlocal exchange and correlation are essential for a more reliable description of large charge-transfer excited states, applicability of the functionals incorporating these terms, namely, parameterized and parameter-free DHs, has also been evaluated. Perusing the role of exact-like exchange, perturbative-like correlation, solvent effects, and other related factors, we find that the parameterized functionals B2π-PLYP and B2GP-PLYP and the parameter-free models PBE-CIDH and PBE-QIDH have respectable performance with respect to others. Lastly, besides the recommendation of reliable computational protocols for the purpose, hopefully this study can pave the way toward further developments of other SHs and DHs for theoretical explorations in the field of OLEDs technology.

  6. Reducing nitrogen crossover in microbial reverse-electrodialysis cells by using adjacent anion exchange membranes and anion exchange resin

    KAUST Repository

    Wallack, Maxwell J.

    2015-01-01

    Microbial reverse electrodialysis cells (MRECs) combine power generation from salinity gradient energy using reverse electrodialysis (RED), with power generation from organic matter using a microbial fuel cell. Waste heat can be used to distill ammonium bicarbonate into high (HC) and low salt concentration (LC) solutions for use in the RED stack, but nitrogen crossover into the anode chamber must be minimized to avoid ammonia loses, and foster a healthy microbial community. To reduce nitrogen crossover, an additional low concentration (LC) chamber was inserted before the anode using an additional anion exchange membrane (AEM) next to another AEM, and filled with different amounts of anion or cation ion exchange resins. Addition of the extra AEM increased the ohmic resistance of the test RED stack from 103 Ω cm2 (1 AEM) to 295 Ω cm2 (2 AEMs). However, the use of the anion exchange resin decreased the solution resistance of the LC chamber by 74% (637 Ω cm2, no resin; 166 Ω cm2 with resin). Nitrogen crossover into the anode chamber was reduced by up to 97% using 50% of the chamber filled with an anion exchange resin compared to the control (no additional chamber). The added resistance contributed by the use of the additional LC chamber could be compensated for by using additional LC and HC membrane pairs in the RED stack.

  7. Optimisation of Double Pipe Helical Tube Heat Exchanger and its Comparison with Straight Double Tube Heat Exchanger

    Science.gov (United States)

    Kareem, Rashid

    2017-10-01

    Optimization of double pipe helical coil heat exchanger with various optimizing parameters and its comparison with double pipe straight tube are the prime objectives of this paper. Numerical studies were performed with the aid of a commercial computational fluid dynamics package ANSYS FLUENT 14. In this paper the double pipe helical coil is analysed under turbulent flow conditions for optimum heat exchanger properties. The parameters used for optimization are cross-sectional shape and taper angles. Optimization analysis is being carried out for finding best cross sectional shape of heat exchanger coils by using rectangular, square, triangular and circular cross-sections. The tapered double pipe helical coil is then analysed for best heat transfer and pressure drop characteristics by varying the angle of taper. Finally, an optimum coil on the basis of all the analysis is selected. This optimized double pipe helical coil is compared with double pipe straight tube of equivalent cross-sectional area and length as that of unwounded length of double pipe helical coil.

  8. Magnetic S-parameter

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2010-01-01

    We propose a direct test of the existence of gauge duals for nonsupersymmetric asymptotically free gauge theories developing an infrared fixed point by computing the S-parameter in the electric and dual magnetic description. In particular we show that at the lower bound of the conformal window...... the magnetic S-parameter, i.e. the one determined via the dual magnetic gauge theory, assumes a simple expression in terms of the elementary magnetic degrees of freedom. The results further support our recent conjecture of the existence of a universal lower bound on the S parameter and indicates...... that it is an ideal operator for counting the active physical degrees of freedom within the conformal window. Our results can be directly used to unveil possible four dimensional gauge duals and constitute the first explicit computation of a nonperturbative quantity, in the electric variables, via nonsupersymmetric...

  9. Diffusive and Arrestedlike Dynamics in Currency Exchange Markets

    Science.gov (United States)

    Clara-Rahola, J.; Puertas, A. M.; Sánchez-Granero, M. A.; Trinidad-Segovia, J. E.; de las Nieves, F. J.

    2017-02-01

    This work studies the symmetry between colloidal dynamics and the dynamics of the Euro-U.S. dollar currency exchange market (EURUSD). We consider the EURUSD price in the time range between 2001 and 2015, where we find significant qualitative symmetry between fluctuation distributions from this market and the ones belonging to colloidal particles in supercooled or arrested states. In particular, we find that models used for arrested physical systems are suitable for describing the EURUSD fluctuation distributions. Whereas the corresponding mean-squared price displacement (MSPD) to the EURUSD is diffusive for all years, when focusing in selected time frames within a day, we find a two-step MSPD when the New York Stock Exchange market closes, comparable to the dynamics in supercooled systems. This is corroborated by looking at the price correlation functions and non-Gaussian parameters and can be described by the theoretical model. We discuss the origin and implications of this analogy.

  10. Oscillating flow loss test results in Stirling engine heat exchangers

    Science.gov (United States)

    Koester, G.; Howell, S.; Wood, G.; Miller, E.; Gedeon, D.

    1990-01-01

    The results are presented for a test program designed to generate a database of oscillating flow loss information that is applicable to Stirling engine heat exchangers. The tests were performed on heater/cooler tubes of various lengths and entrance/exit configurations, on stacked and sintered screen regenerators of various wire diameters and on Brunswick and Metex random fiber regenerators. The test results were performed over a range of oscillating flow parameters consistent with Stirling engine heat exchanger experience. The tests were performed on the Sunpower oscillating flow loss rig which is based on a variable stroke and variable frequency linear drive motor. In general, the results are presented by comparing the measured oscillating flow losses to the calculated flow losses. The calculated losses are based on the cycle integration of steady flow friction factors and entrance/exit loss coefficients.

  11. Heat transfer studies on spiral plate heat exchanger

    Directory of Open Access Journals (Sweden)

    Rajavel Rangasamy

    2008-01-01

    Full Text Available In this paper, the heat transfer coefficients in a spiral plate heat exchanger are investigated. The test section consists of a plate of width 0.3150 m, thickness 0.001 m and mean hydraulic diameter of 0.01 m. The mass flow rate of hot water (hot fluid is varying from 0.5 to 0.8 kg/s and the mass flow rate of cold water (cold fluid varies from 0.4 to 0.7 kg/s. Experiments have been conducted by varying the mass flow rate, temperature, and pressure of cold fluid, keeping the mass flow rate of hot fluid constant. The effects of relevant parameters on spiral plate heat exchanger are investigated. The data obtained from the experimental study are compared with the theoretical data. Besides, a new correlation for the Nusselt number which can be used for practical applications is proposed.

  12. PARAMETER DESIGN PROPELLER KAPAL

    Directory of Open Access Journals (Sweden)

    Muhammad Ridwan

    2012-04-01

    Full Text Available   Designer propeller kapal harus mempertimbangkan berbagai parameter untuk menghasilkan bentuk, type dan ukuran propeller yang memiliki nilai  efektifitas dan effisiensi propulsi tinggi. Propulsi kapal merupakan faktor yang mendominasi  operasional kapal, karena pemakaian bahan bakar untuk operasional propulsi kapal merupakan 42% dari total cost operasional kapal dan merupakan added value yang akan diperoleh oleh perusahaan pelayaran. Pertimbangan parameter desain propeller argonomis dapat mendukung tujuan di atas sehingga dapat menurunkan pemakaian bahan bakar hingga 20 % saat kapal dioperaionalkan.

  13. Bifurcation without parameters

    CERN Document Server

    Liebscher, Stefan

    2015-01-01

    Targeted at mathematicians having at least a basic familiarity with classical bifurcation theory, this monograph provides a systematic classification and analysis of bifurcations without parameters in dynamical systems. Although the methods and concepts are briefly introduced, a prior knowledge of center-manifold reductions and normal-form calculations will help the reader to appreciate the presentation. Bifurcations without parameters occur along manifolds of equilibria, at points where normal hyperbolicity of the manifold is violated. The general theory, illustrated by many applications, aims at a geometric understanding of the local dynamics near the bifurcation points.

  14. Heat exchanger with oscillating flow

    Science.gov (United States)

    Scotti, Stephen J. (Inventor); Blosser, Max L. (Inventor); Camarda, Charles J. (Inventor)

    1993-01-01

    Various heat exchange apparatuses are described in which an oscillating flow of primary coolant is used to dissipate an incident heat flux. The oscillating flow may be imparted by a reciprocating piston, a double action twin reciprocating piston, fluidic oscillators or electromagnetic pumps. The oscillating fluid flows through at least one conduit in either an open loop or a closed loop. A secondary flow of coolant may be used to flow over the outer walls of at least one conduit to remove heat transferred from the primary coolant to the walls of the conduit.

  15. IRON EXCHANGE IN MYCOBACTERIA

    OpenAIRE

    V. L. Dobin; V. G. Demikhov; M. P. Zharikova

    2016-01-01

    The review analyzes the major foreign publications on the iron exchange in mycobacteria for the recent years. The issues of iron absorption by tuberculous mycobacteria, its preservation and regulation of their metabolism have been reviewed. Deeper and more detail description of the above process will provide new opportunities for therapeutic interventions into it and assist in development of new tuberculosis treatment techniques.

  16. IRON EXCHANGE IN MYCOBACTERIA

    Directory of Open Access Journals (Sweden)

    V. L. Dobin

    2016-01-01

    Full Text Available The review analyzes the major foreign publications on the iron exchange in mycobacteria for the recent years. The issues of iron absorption by tuberculous mycobacteria, its preservation and regulation of their metabolism have been reviewed. Deeper and more detail description of the above process will provide new opportunities for therapeutic interventions into it and assist in development of new tuberculosis treatment techniques.

  17. EPR of exchange coupled systems

    CERN Document Server

    Bencini, Alessandro

    2012-01-01

    From chemistry to solid state physics to biology, the applications of Electron Paramagnetic Resonance (EPR) are relevant to many areas. This unified treatment is based on the spin Hamiltonian approach and makes extensive use of irreducible tensor techniques to analyze systems in which two or more spins are magnetically coupled. This edition contains a new Introduction by coauthor Dante Gatteschi, a pioneer and scholar of molecular magnetism.The first two chapters review the foundations of exchange interactions, followed by examinations of the spectra of pairs and clusters, relaxation in oligon

  18. Newton's Contributions to Optics

    Indian Academy of Sciences (India)

    Newton's epochal work on dynamics and gravitation some- times tends to eclipse his great contributions to optics. Also, his work in optics is rivalled by equally significant work by his contemporaries, especially Huygens. Yet his creativity is apparent, even in ideas and models in optics that were later abandoned in science. 1.

  19. Contributions to climate summit

    NARCIS (Netherlands)

    Wassink, J.

    2015-01-01

    Politicians will meet at the Climate Summit in Paris to discuss the IPCC (Intergovernmental Panel on Climate Change) report. It provides an overview of the current state of climate knowledge, based on the work of thousands of scientists all over the world. Delft researchers have also contributed in

  20. Newton's Contributions to Optics

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 12. Newton's Contributions to Optics. Arvind Kumar. General Article Volume 11 Issue 12 December 2006 pp 10-20. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/011/12/0010-0020. Keywords.

  1. A proud contribution

    African Journals Online (AJOL)

    The views expressed in this piece reflect the opinion of the writer only, and no other organisation to which he belongs. Franco Colin. PO Box 75772. Lynnwoodridge. 0040. Volume 10 No. 3 October 2004 - SAJP. A proud contribution. Franco Colin is a psychiatrist in private practice and a part-time consultant in.

  2. Czech Contribution to Athena

    Directory of Open Access Journals (Sweden)

    R. Hudec

    2011-01-01

    Full Text Available We describe the recent status of the Czech contribution to the ESA Athena space mission, with emphasis on the development of new technologies and test samples of X-ray mirrors with precise surfaces, based on new materials, and their applications in space. In addition, alternative X-ray optical arrangements are investigated, such as Kirkpatrick-Baez systems.

  3. Fisher's Contributions to Statistics

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 9. Fisher's Contributions to Statistics. T Krishnan. General Article Volume 2 Issue 9 September 1997 pp 32-37 ... Author Affiliations. T Krishnan1. Computer Science Unit, Indian Statistical Institute, 203 B T Road, Calcutta 700 035, India ...

  4. Fisher's Contributions to Statistics

    Indian Academy of Sciences (India)

    its applications, especially to agriculture and the design of experiments therein. His contributions to statistics are so many that it is not even possible to mention them all in this short article. We, therefore, confine our attention to discussing what we regard as the more important among them. Fisher provided a unified and ...

  5. Group Contribution Methods for Phase Equilibrium Calculations.

    Science.gov (United States)

    Gmehling, Jürgen; Constantinescu, Dana; Schmid, Bastian

    2015-01-01

    The development and design of chemical processes are carried out by solving the balance equations of a mathematical model for sections of or the whole chemical plant with the help of process simulators. For process simulation, besides kinetic data for the chemical reaction, various pure component and mixture properties are required. Because of the great importance of separation processes for a chemical plant in particular, a reliable knowledge of the phase equilibrium behavior is required. The phase equilibrium behavior can be calculated with the help of modern equations of state or g(E)-models using only binary parameters. But unfortunately, only a very small part of the experimental data for fitting the required binary model parameters is available, so very often these models cannot be applied directly. To solve this problem, powerful predictive thermodynamic models have been developed. Group contribution methods allow the prediction of the required phase equilibrium data using only a limited number of group interaction parameters. A prerequisite for fitting the required group interaction parameters is a comprehensive database. That is why for the development of powerful group contribution methods almost all published pure component properties, phase equilibrium data, excess properties, etc., were stored in computerized form in the Dortmund Data Bank. In this review, the present status, weaknesses, advantages and disadvantages, possible applications, and typical results of the different group contribution methods for the calculation of phase equilibria are presented.

  6. A novel erythroid anion exchange variant (Gly796Arg) of hereditary stomatocytosis associated with dyserythropoiesis

    Science.gov (United States)

    Iolascon, Achille; De Falco, Luigia; Borgese, Franck; Esposito, Maria Rosaria; Avvisati, Rosa Anna; Izzo, Pietro; Piscopo, Carmelo; Guizouarn, Helene; Biondani, Andrea; Pantaleo, Antonella; De Franceschi, Lucia

    2009-01-01

    Background Stomatocytoses are a group of inherited autosomal dominant hemolytic anemias and include overhydrated hereditary stomatocytosis, dehydrated hereditary stomatocytosis, hereditary cryohydrocytosis and familial pseudohyperkalemia. Design and Methods We report a novel variant of hereditary stomatocytosis due to a de novo band 3 mutation (p. G796R-band3 CEINGE) associated with a dyserythropoietic phenotype. Band 3 genomic analysis, measurement at of hematologic parameters and red cell indices and morphological analysis of bone marrow were carried out. We then evaluated the red cell membrane permeability and ion transport systems by functional studies of the patient’s erythrocytes and Xenopus oocytes transfected with mutated band 3. We analyzed the red cell membrane tyrosine phosphorylation profile and the membrane association of the tyrosine kinases Syk and Lyn from the Src-family-kinase group, since the activity of the membrane cation transport pathways is related to cyclic phosphorylation-dephosphorylation events. Results The patient showed mild hemolytic anemia with circulating stomatocytes together with signs of dyserythropoiesis. Her red cells displayed increased Na+ content with decreased K+content and abnormal membrane cation transport activities. Functional characterization of band 3 CEINGE in Xenopus oocytes showed that the mutated band 3 is converted from being an anion exchanger (Cl−, HCO3−) to being a cation pathway for Na+ and K+. Increased tyrosine phosphorylation of some red cell membrane proteins was observed in diseased erythrocytes. Syk and Lyn membrane association was increased in the patient’s red cells compared to in normal controls, indicating perturbation of phospho-signaling pathways involved in cell volume regulation events. Conclusions Band 3 CEINGE alters function from that of anion exchange to cation transport, affects the membrane tyrosine phosphorylation profile, in particular of band 3 and stomatin, and its presence

  7. Design Guideline for Primary Heat Exchanger in a Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sunil; Seo, Kyoung-Woo; Kim, Seong-Hoon; Chi, Dae-Young; Park, Cheol [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In this paper, analytical study is conducted to track the variation of the PCS outlet temperature in conditions of the constant core power and constant SCS inlet temperature. The PCS circulates demineralized water to remove the heat generated in reactor core. The heat is transferred to the cold water of the SCS through the primary heat exchanger. In JRTR, Plate-type Heat Exchanger (PHE) was used as the primary heat exchanger. The cooling tower automatically sets the SCS inlet temperature constant by fan speed control. The flow rate of SCS is adjusted to be identical with the PCS flow rate. To design the PHE, the inlet and outlet temperatures and the flow rates for both systems should be determined. The flow rate has the allowable band for the safe operation from the lower limit to upper limit resulting in different temperature distribution in the PHE. Specially, the PCS outlet temperature which is the core inlet temperature is used for a safety parameter for the reactor shutdown. Therefore, we need to figure out which limit for the flow rate should be used from the conservative point of view. At 200 kg/s of PCS and SCS flow rates, the inlet and outlet temperatures are 41.3℃and 34℃, respectively. With increase of the flow rate, both of PCS inlet and outlet temperatures decrease to 33.6℃ and 39.9℃. This result means the low limit of the allowable flow band should be used for the conservative design of primary heat exchanger. If the upper limit of the allowable flow band is used, the PCS outlet temperature which is the safety parameter used for the reactor shutdown increases with decrease of the flow rate.

  8. Magnetization processes in core/shell exchange-spring structures.

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, J. S.

    2015-03-27

    The magnetization reversal processes in cylindrical and spherical soft core/hard shell exchange-spring structures are investigated via the analytical nucleation theory, and are verified with numerical micromagnetic simulations. At small core sizes, the nucleation of magnetic reversal proceeds via the modified bulging mode, where the transverse component of the magnetization is only semi-coherent in direction and the nucleation field contains a contribution from self-demagnetization. For large core sizes, the modified curling mode, where the magnetization configuration is vortex-like, is favored at nucleation. The preference for the modified curling mode is beneficial in that the fluxclosure allows cylindrical and spherical core/shell exchange-spring elements to be densely packed into bulk permanent magnets without affecting the nucleation field, thereby offering the potential for high energy product.

  9. Lipid exchange between Borrelia burgdorferi and host cells.

    Directory of Open Access Journals (Sweden)

    Jameson T Crowley

    2013-01-01

    Full Text Available Borrelia burgdorferi, the agent of Lyme disease, has cholesterol and cholesterol-glycolipids that are essential for bacterial fitness, are antigenic, and could be important in mediating interactions with cells of the eukaryotic host. We show that the spirochetes can acquire cholesterol from plasma membranes of epithelial cells. In addition, through fluorescent and confocal microscopy combined with biochemical approaches, we demonstrated that B. burgdorferi labeled with the fluorescent cholesterol analog BODIPY-cholesterol or (3H-labeled cholesterol transfer both cholesterol and cholesterol-glycolipids to HeLa cells. The transfer occurs through two different mechanisms, by direct contact between the bacteria and eukaryotic cell and/or through release of outer membrane vesicles. Thus, two-way lipid exchange between spirochetes and host cells can occur. This lipid exchange could be an important process that contributes to the pathogenesis of Lyme disease.

  10. BASIMO - Borehole Heat Exchanger Array Simulation and Optimization Tool

    Science.gov (United States)

    Schulte, Daniel O.; Bastian, Welsch; Wolfram, Rühaak; Kristian, Bär; Ingo, Sass

    2017-04-01

    Arrays of borehole heat exchangers are an increasingly popular source for renewable energy. Furthermore, they can serve as borehole thermal energy storage (BTES) systems for seasonally fluctuating heat sources like solar thermal energy or district heating grids. The high temperature level of these heat sources prohibits the use of the shallow subsurface for environmental reasons. Therefore, deeper reservoirs have to be accessed instead. The increased depth of the systems results in high investment costs and has hindered the implementation of this technology until now. Therefore, research of medium deep BTES systems relies on numerical simulation models. Current simulation tools cannot - or only to some extent - describe key features like partly insulated boreholes unless they run fully discretized models of the borehole heat exchangers. However, fully discretized models often come at a high computational cost, especially for large arrays of borehole heat exchangers. We give an update on the development of BASIMO: a tool, which uses one dimensional thermal resistance and capacity models for the borehole heat exchangers coupled with a numerical finite element model for the subsurface heat transport in a dual-continuum approach. An unstructured tetrahedral mesh bypasses the limitations of structured grids for borehole path geometries, while the thermal resistance and capacity model is improved to account for borehole heat exchanger properties changing with depth. Thereby, partly insulated boreholes can be considered in the model. Furthermore, BASIMO can be used to improve the design of BTES systems: the tool allows for automated parameter variations and is readily coupled to other code like mathematical optimization algorithms. Optimization can be used to determine the required minimum system size or to increase the system performance.

  11. Band parameters of phosphorene

    DEFF Research Database (Denmark)

    Lew Yan Voon, L. C.; Wang, J.; Zhang, Y.

    2015-01-01

    Phosphorene is a two-dimensional nanomaterial with a direct band-gap at the Brillouin zone center. In this paper, we present a recently derived effective-mass theory of the band structure in the presence of strain and electric field, based upon group theory. Band parameters for this theory...

  12. Response model parameter linking

    NARCIS (Netherlands)

    Barrett, M.L.D.

    2015-01-01

    With a few exceptions, the problem of linking item response model parameters from different item calibrations has been conceptualized as an instance of the problem of equating observed scores on different test forms. This thesis argues, however, that the use of item response models does not require

  13. Measuring the chargino parameters

    Indian Academy of Sciences (India)

    Instytut Fizyki Teoretycznej UW, Hoza 69, 00681 Warszawa, Poland. Abstract. After the supersymmetric particles have been discovered, the priority will ... the priority will be to determine the low-energy Lagrangian parameters. This will allow us to verify the relations among them, if any, in order to distinguish between various.

  14. 31 CFR 515.325 - National securities exchange.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false National securities exchange. 515.325... Definitions § 515.325 National securities exchange. The term national securities exchange shall mean an exchange registered as a national securities exchange under section 6 of the Securities Exchange Act of...

  15. 31 CFR 500.325 - National securities exchange.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false National securities exchange. 500.325... Definitions § 500.325 National securities exchange. The term national securities exchange shall mean an exchange registered as a national securities exchange under section 6 of the Securities Exchange Act of...

  16. Inorganic ion exchangers for nuclear waste remediation

    Energy Technology Data Exchange (ETDEWEB)

    Clearfield, A.; Bortun, A.; Bortun, L.; Behrens, E. [Texas A& M Univ., College Station, TX (United States)

    1997-10-01

    The objective of this work is to provide a broad spectrum of inorganic ion exchangers that can be used for a range of applications and separations involving remediation of groundwater and tank wastes. The authors intend to scale-up the most promising exchangers, through partnership with AlliedSignal Inc., to provide samples for testing at various DOE sites. While much of the focus is on exchangers for removal of Cs{sup +} and Sr{sup 2+} from highly alkaline tank wastes, especially at Hanford, the authors have also synthesized exchangers for acid wastes, alkaline wastes, groundwater, and mercury, cobalt, and chromium removal. These exchangers are now available for use at DOE sites. Many of the ion exchangers described here are new, and others are improved versions of previously known exchangers. They are generally one of three types: (1) layered compounds, (2) framework or tunnel compounds, and (3) amorphous exchangers in which a gel exchanger is used to bind a fine powder into a bead for column use. Most of these exchangers can be regenerated and used again.

  17. How did China's foreign exchange reform affect the efficiency of foreign exchange market?

    Science.gov (United States)

    Ning, Ye; Wang, Yiming; Su, Chi-wei

    2017-10-01

    This study compares the market efficiency of China's onshore and offshore foreign exchange markets before and after the foreign exchange reform on August 11, 2015. We use the multifractal detrended fluctuation analysis of the onshore and offshore RMB/USD spot exchange rate series as basis. We then find that the onshore foreign exchange market before the reform has the lowest market efficiency, which increased after the reform. The offshore foreign exchange market before the reform has the highest market efficiency, which dropped after the reform. This finding implies the increased efficiency of the onshore foreign exchange market and the loss of efficiency in the offshore foreign exchange market. We also find that the offshore foreign exchange market is more efficient than the onshore market and that the gap shrank after the reform. Changes in intervention of the People's Bank of China since the reform is a possible explanation for the changes in the efficiency of the foreign exchange market.

  18. 75 FR 43799 - Employee Contribution Elections and Contribution Allocations

    Science.gov (United States)

    2010-07-27

    ... Part 1600 Employee Contribution Elections and Contribution Allocations AGENCY: Federal Retirement...: PART 1600--EMPLOYEE CONTRIBUTION ELECTIONS AND CONTRIBUTION ALLOCATIONS 0 1. The authority citation for... contribution allocation and/or an interfund transfer; and (d) The employee's ability to request a refund of any...

  19. Phase-exchange thermoacoustic engine

    Science.gov (United States)

    Offner, Avshalom; Meir, Avishai; Ramon, Guy Z.; WET Lab Team

    2017-11-01

    Phase-exchange thermoacoustic engines are reliable machines holding great promise in converting heat from low grade heat sources to mechanical or electrical power. In these engines the working fluid is a gas mixture containing one condensable component, decreasing the temperature difference required for ignition and steady state operation. Our experimental setup consists of a vertical acoustic resonator containing a mixture of air-water vapor. Water evaporates near the heat source, condenses at the heat sink and is drawn back down by gravity and capillary forces where it re-evaporates, sustaining a steady state closed thermodynamic cycle. We investigated the stability limit, namely the critical point at which temperature difference in the engine enables onset of self-excited oscillations, and the steady state of the engine. A simple theoretical model was derived, describing mechanisms of irreversible entropy generation and production of acoustic power in such engines. This model captures the essence in the differences between regular and phase-exchange thermoacoustic engines, and shows good agreement with experimental results of stability limit. Steady state results reveal not only a dramatic decrease in temperature difference, but also an increase in engine performances. The authors acknowledge the support from the Nancy and Stephen Grand Technion Energy Program (GTEP).

  20. Dipole-induced exchange bias.

    Science.gov (United States)

    Torres, Felipe; Morales, Rafael; Schuller, Ivan K; Kiwi, Miguel

    2017-11-09

    The discovery of dipole-induced exchange bias (EB), switching from negative to positive sign, is reported in systems where the antiferromagnet and the ferromagnet are separated by a paramagnetic spacer (AFM-PM-FM). The magnitude and sign of the EB is determined by the cooling field strength and the PM thickness. The same cooling field yields negative EB for thin spacers, and positive EB for thicker ones. The EB decay profile as a function of the spacer thickness, and the change of sign, are attributed to long-ranged dipole coupling. Our model, which accounts quantitatively for the experimental results, ignores the short range interfacial exchange interactions of the usual EB theories. Instead, it retains solely the long range dipole field that allows for the coupling of the FM and AFM across the PM spacer. The experiments allow for novel switching capabilities of long range EB systems, while the theory allows description of the structures where the FM and AFM are not in atomic contact. The results provide a new approach to design novel interacting heterostructures.