WorldWideScience

Sample records for natural circulation operational

  1. Study on thermal-hydraulics of natural circulation operation for decay heat removal of LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Tomonari [Central Research Inst. of Electric Power Industry, Abiko, Chiba (Japan). Abiko Research Lab

    2000-05-01

    Thermal-hydraulic characteristics of the decay heat removal system (DHRS) has been evaluated by both a water test and its computational analysis. The direct reactor auxiliary cooling system (DRACS) was studied as a representative DHRS in the LMFBR design. A natural circulation flow of the DRACS is originated from the buoyancy force balanced with the pressure loss within the active core. Hence it appears that the performance of the DRACS could be fully estimated by the thermal-hydraulic study of one fuel sub-assembly under the condition of low flow rate. The inter-wrapper flow occurring in the gap between core sub-assemblies under the natural circulation operation might have a large capacity to cool the core. An inverse flow occurring at the outer region of the core was due to the cooling effect of the inter-wrapper flow. (author)

  2. Thermal-hydraulic characteristics of natural circulation operation for decay heat removal of LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Tomonari [Central Research Inst. of Electric Power Industry, Abiko, Chiba (Japan); Watanabe, Osamu [Advanced Reactor Technology Co., Ltd., Tokyo (Japan)

    2000-10-01

    Thermal-hydraulic characteristics of the decay heat removal system (DHRS) has been evaluated by both a water test and its computational analysis. The direct reactor auxiliary cooling system (DRACS) was studied as a representative DHRS in the LMFBR design. A natural circulation flow of the DRACS is originated from the buoyancy force balanced with the pressure loss within the active core. Hence it appears that the performance of the DRACS could be fully estimated by the thermal-hydraulic study of one fuel sub-assembly under the condition of low flow rate. The inter-wrapper flow occurring in the gap between core sub-assemblies under the natural circulation operation might have a large capacity to cool the core. An inverse flow occurring at the outer region of the core was due to the cooling effect of the inter-wrapper flow. (author)

  3. Evaluation of nitrogen gas accumulated inside MCP during natural circulation operation of SMART

    Energy Technology Data Exchange (ETDEWEB)

    Choi, B. S.; Kim, Y. I.; Seo, J. K.; Park, C. T.; Lee, D. J.; Jang, M. H. [KAERI, Taejon (Korea, Republic of)

    2001-10-01

    With nitrogen used in pressurizer, primary coolant of SMART will contain dissolved nitrogen. The solubility of nitrogen gas in water is calculated as a function of temperature and pressure by Himmelblau equation based on Henry's law. It is found that the nitrogen concentration of primary coolant is highly dependent upon thermal-hydraulic parameters of the primary system, temperature, pressure and heatup rate. The accumulated nitrogen gas within MCP is evaluated based on the assumed natural convective flows established between SMART core and MCP. It is concluded that the natural circulation time is varied from 100 {approx} 1000 hrs according to the natural convection flows.

  4. Working regime identification for natural circulation loops by comparative thermalhydraulic analyses with three fluids under identical operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Milan K.S.; Basu, Dipankar N., E-mail: dipankar.n.basu@gmail.com

    2015-11-15

    Highlights: • Thermalhydraulic analyses of NCL to justify the use of supercritical condition. • Mass flow rate of supercritical loop increases with heater power till a maxima. • Supercritical loop suffer from HTD beyond the maxima with jump in fluid temperature. • HTD is pronounced at higher sink temperatures and pressures just above critical. • Supercritical CO{sub 2} is preferred fluid till the HTD and single-phase water afterwards. - Abstract: Computational investigation for comparative thermalhydraulic analyses of rectangular natural circulation loops is performed to propose a guideline for selecting the working fluid and nature of the loop, subcritical or supercritical, under identical levels of operating parameters like pressure, heating power and coolant temperature. A 3-d uniform-diameter loop geometry is developed with horizontal heating and cooling. Heating is provided in constant heat flux mode, whereas cooling is through a constant temperature sink. Due to favourable thermophysical properties and environmental conformity, water, CO{sub 2} and R134a are selected as possible working fluids. Operational parameters are set so as to have sub- to supercritical condition for CO{sub 2}, supercritical for R134a and single-phase liquid for water. Mass flow rate for supercritical fluid rapidly increases with heater power, when the fluid is allowed to cross the pseudocritical point during its passage through the heater, and exhibits a maxima. Drastic fall in mass flow rate can be observed beyond the maxima, accompanied by a jump in maximum fluid temperature and a rapid decline in sink-side heat transfer coefficient. That can be identified as heat transfer deterioration in supercritical natural circulation loops, a highly undesirable situation from loop safety point of view. Allowable working range of heater power can be enhanced by increasing system pressure and decreasing sink temperature. For any specified set of operating conditions, CO{sub 2}-based

  5. Quenching phenomena in natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Umekawa, Hisashi; Ozawa, Mamoru [Kansai Univ., Osaka (Japan); Ishida, Naoki [Daihatsu Motor Company, Osaka (Japan)

    1995-09-01

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

  6. Efficient quantum circuits for dense circulant and circulant like operators

    Science.gov (United States)

    Zhou, S. S.; Wang, J. B.

    2017-05-01

    Circulant matrices are an important family of operators, which have a wide range of applications in science and engineering-related fields. They are, in general, non-sparse and non-unitary. In this paper, we present efficient quantum circuits to implement circulant operators using fewer resources and with lower complexity than existing methods. Moreover, our quantum circuits can be readily extended to the implementation of Toeplitz, Hankel and block circulant matrices. Efficient quantum algorithms to implement the inverses and products of circulant operators are also provided, and an example application in solving the equation of motion for cyclic systems is discussed.

  7. Cooling Performance of Natural Circulation for a Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Suki; Chun, J. H.; Yum, S. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    This paper deals with the core cooling performance by natural circulation during normal operation and a flow channel blockage event in an open tank-in-pool type research reactor. The cooling performance is predicted by using the RELAP5/ MOD3.3 code. The core decay heat is usually removed by natural circulation to the reactor pool water in open tank-in-pool type research reactors with the thermal power less than several megawatts. Therefore, these reactors have generally no active core cooling system against a loss of normal forced flow. In reactors with the thermal power less than around one megawatt, the reactor core can be cooled down by natural circulation even during normal full power operation. The cooling performance of natural circulation in an open tank-in-pool type research reactor has been investigated during the normal natural circulation and a flow channel blockage event. It is found that the maximum powers without void generation at the hot channel are around 1.16 MW and 820 kW, respectively, for the normal natural circulation and the flow channel blockage event.

  8. The immunity of the ICMS (Circulation Tax) on interstate operations involving natural gas; Da imunidade do ICMS (Imposto sobre Circulacao de Mercadorias e Servicos) em operacoes interestaduais envolvendo gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Yvy, Maytta A.S.; Galvao, Katia C.P.; Mendonca, Fabiano A.S. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Faculdade de Direito

    2004-07-01

    The Federal Constitution of Brazil, in the article 155, para. 2nd, X, b, determines that there will not be Circulation Taxs (ICMS) over operations that destinates to other States petroleum, including lubricants, liquid and gaseous fuels of him derived. It establishes, therefore, hypothesis of tributary immunity. However, the interpretation of this rule in the juridical scenery is rounded by doubts. There are two possible interpretations: or the natural gas is included in this hypothesis of tributary immunity, considering it is a derived gaseous fuel of the petroleum or, in the other hand, it is not included in the hypothesis, since it is not admitted as a petroleum product. Using not juridical interpretative elements and using constitutional principles and interpretative rules, the conclusion is that the natural gas doesn't integrate the normative hypothesis, in view that the opposite comprehension would surpass the meaning of the norm in exam, falling in inconstitutionality. However, having in mind the convenience of enlarging the natural gas participation in the national energy head office, the possibility of granting tributary discharge through exemption of ICMS over operations between States involving natural gas is open. (author)

  9. Experimental study of natural circulation circuit

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Wanderley F.; Su, Jian, E-mail: wlemos@lasme.coppe.ufrj.br, E-mail: sujian@lasme.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao de Engenharia (LASME/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Simulacao e Metodos Numericos; Faccini, Jose L.H., E-mail: faccini@ien.gov.br [Instituto de Engenharia Nuclear (LTE/IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. de Termo-Hidraulica Experimental

    2011-07-01

    This work presents an experimental study about fluid flows behavior in natural circulation, under conditions of single-phase flow. The experiment was performed through experimental thermal-hydraulic circuit built at IEN. This test equipment has performance similar to passive system of residual heat removal present in Advanced Pressurized Water Reactors (APWR). This experimental study aims to observing and analyzing the natural circulation phenomenon, using this experimental circuit that was dimensioned and built based on concepts of similarity and scale. This philosophy allows the analysis of natural circulation behavior in single-phase flow conditions proportionally to the functioning real conditions of a nuclear reactor. The experiment was performed through procedures to initialization of hydraulic feeding of primary and secondary circuits and electrical energizing of resistors installed inside heater. Power controller has availability to adjust values of electrical power to feeding resistors, in order to portray several conditions of energy decay of nuclear reactor in a steady state. Data acquisition system allows the measurement and monitoring of the evolution of the temperature in various points through thermocouples installed in strategic points along hydraulic circuit. The behavior of the natural circulation phenomenon was monitored by graphical interface on computer screen, showing the temperature evolutions of measuring points and results stored in digital spreadsheets. The results stored in digital spreadsheets allowed the getting of data to graphic construction and discussion about natural circulation phenomenon. Finally, the calculus of Reynolds number allowed the establishment for a correlation of friction in function of geometric scales of length, heights and cross section of tubing, considering a natural circulation flow throughout in the region of hot leg. (author)

  10. Experimental study of two-phase natural circulation circuit

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Wanderley Freitas; Su, Jian, E-mail: wlemos@lasme.coppe.ufrj.br, E-mail: sujian@nuclear.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Faccini, Jose Luiz Horacio, E-mail: faccini@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), RIo de Janeiro, RJ (Brazil). Lab. de Termo-Hidraulica Experimental

    2012-07-01

    This paper reports an experimental study on the behavior of fluid flow in natural circulation under single-and two-phase flow conditions. The natural circulation circuit was designed based on concepts of similarity and scale in proportion to the actual operating conditions of a nuclear reactor. This test equipment has similar performance to the passive system for removal of residual heat presents in Advanced Pressurized Water Reactors (A PWR). The experiment was carried out by supplying water to primary and secondary circuits, as well as electrical power resistors installed inside the heater. Power controller has available to adjust the values for supply of electrical power resistors, in order to simulate conditions of decay of power from the nuclear reactor in steady state. Data acquisition system allows the measurement and control of the temperature at different points by means of thermocouples installed at several points along the circuit. The behavior of the phenomenon of natural circulation was monitored by a software with graphical interface, showing the evolution of temperature measurement points and the results stored in digital format spreadsheets. Besides, the natural circulation flow rate was measured by a flowmeter installed on the hot leg. A flow visualization technique was used the for identifying vertical flow regimes of two-phase natural circulation. Finally, the Reynolds Number was calculated for the establishment of a friction factor correlation dependent on the scale geometrical length, height and diameter of the pipe. (author)

  11. Circulating fluidized bed boilers design and operations

    CERN Document Server

    Basu, Prabir

    1991-01-01

    This book provides practicing engineers and students with insight into the design and operation of circulating fluidized bed (CFB) boilers. Through a combination of theoretical concepts and practical experience, this book gives the reader a basic understanding of the many aspects of this subject.Important environmental considerations, including solid waste disposal and predicted emissions, are addressed individually in separate chapters. This book places an emphasis on combustion, hydrodynamics, heat transfer, and material issues, and illustrates these concepts with numerous examples of pres

  12. Severe accident natural circulation studies at the INEL

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-02-01

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

  13. Experimental and Analytical Modeling of Natural Circulation and Forced Circulation BWRs : Thermal-Hydraulic, Core-Wide, and Regional Stability Phenomena

    OpenAIRE

    2006-01-01

    Currently, 434 nuclear power plants are in operation worldwide. 21% of them are known as Boiling Water Reactors (BWRs). These BWRs have pumps that cool their reactor cores (the forced circulation BWRs). In the design of new BWRs, ways to cool the core by a natural circulation flow, without pumps, also called natural circulation BWRs, are being considered. A possible disadvantage of natural circulation BWRs might be their susceptibility to instabilities, which could then lead to both flow and ...

  14. Numerical simulation of a natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Verissimo, Gabriel L.; Moreira, Maria de Lourdes; Faccini, Jose Luiz H., E-mail: gabrielverissimo@poli.ufrj.b, E-mail: malu@ien.gov.b, E-mail: faccini@ien.gov.b [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    This work presents a numerical simulation of a natural circulation loop using computational fluid dynamics. The simulated loop is an experimental model in a reduced scale of 1:10 of a passive heat removal system typical of advanced PWR reactors. The loop is composed of a heating vessel containing 52 electric heaters, a vertical shell-tube heat exchanger and a column of expansion. The working fluid is distilled water. Initially it was created a tridimensional geometric model of the loop components. After that, it was generated a tridimensional mesh of finite elements in order to calculate the variables of the problem. The boundaries of the numerical simulation were the power of the electric resistances and the cooling flow in the secondary side of the heat exchanger. The initial conditions were the temperature, the pressure and the fluid velocity at the time just before the power has been switched on. The results of this simulation were compared with the experimental data, in terms of the evolution of the temperatures in different locations of the loop, and of the average natural circulation flow as a function of time for a given power. (author)

  15. Experimental natural circulation circuit - preliminaries results; Circuito experimental de circulacao natural - resultados experimentais preliminares

    Energy Technology Data Exchange (ETDEWEB)

    Faccini, Jose Luiz H.; Botelho, David A.; Soares, Milton; Coutinho, Jorge A.; Freitas, Sergio Carlos [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil). E-mail: faccini@cnen.gov.br

    2000-07-01

    These are the preliminaries results of the tests carried out at experimental natural circulation system of IEN/CNEN. The experimental system is a reduced scale similar model in power, pressure, and length of a passive residual heat removal prototype system. It enables studies of natural circulation phenomena in an advanced PWR. The experimental results refer to the steps of data acquisition system calibration, power control system calibration, and single-phase operational tests. The results of single-phase tests show temperature in time measured by the thermocouples placed along the natural circulation system. It is also presented a brief commentary on the experimental results, based on theory and preliminary computational simulations. (author)

  16. Stability analysis on natural circulation boiling water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Metz, Peter

    1999-05-01

    The purpose of the study is a stability analysis of the simplified boiling water reactor concept. A fluid dynamics code, DYNOS, was developed and successfully validated against FRIGG and DESIRE data and a stability benchmark on the Ringhals 1 forced circulation BWR. Three simplified desings were considered in the analysis: The SWRIOOO by Siemens and the SBWR and ESBWR from the General Electric Co. For all three design operational characteristics, i.e. power versus flow rate maps, were calculated. The effects which different geometric and operational parameters, such as the riser height, inlet subcooling etc., have on the characteristics have been investigated. Dynamic simulations on the three simplified design revealed the geysering and the natural circulation oscillations modes only. They were, however, only encountered at pressure below 0.6 MPa. Stability maps for all tree simplified BWRs were calculated and plotted. The study concluded that a fast pressurisation of the reactor vessel is necessary to eliminate the possibility of geysering or natural circulation oscillations mode instability. (au) 26 tabs., 88 ills.

  17. Conceptual analysis of a preliminary model for instability study in normal operation of a natural circulation reactor type EBWR, using Relap5/Mod 3.2; Analisis conceptual de un modelo preliminar para el estudio de la inestabilidad en la operacion normal de un reactor de circulacion natural tipo ESBWR, usando Relap5/Mod 3.2

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda S, J.; Morales S, J.; Chavez M, C. [UNAM, Facultad de Ingenieria, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)], e-mail: j.os.ojeda@hotmail.com

    2009-10-15

    This work intends a model using the code Relap5/Mod 3.2, for the instability study in normal operation of a natural circulation reactor type ESBWR. A conceptual analysis is considered because all the information was obtained of the open literature, and some of reactor operation or dimension (not available) parameters were approached. As starting point was took the pattern developed for reactor type BWR, denominated Browns Ferry and changes were focused in elimination of bonds of forced recirculation, in modification of operation parameters, dimensions and own control parameters, according to internal code structure. Additionally the nodalization outline is described analyzing for separate the four fundamental areas employees in peculiar geometry of natural circulation reactor. Comparative analysis of results of stability behavior obtained with those reported in the open literature were made, by part of commercial reactor designer ESBWR. (Author)

  18. Use of the Natural Circulation Flow Map for Natural Circulation Systems Evaluation

    Directory of Open Access Journals (Sweden)

    M. Cherubini

    2008-01-01

    Full Text Available The aim of this paper is to collect and resume the work done to build and develop, at the University of Pisa, an engineering tool related to the natural circulation. After a brief description of the different loop flow regimes in single phase and two phase, the derivation of a suitable tool to judge the NC performance in a generic system is presented. Finally, an extensive comparison among the NC performance of various nuclear power plants having different design is done to show a practical application of the NC flow map.

  19. Parametric study on a natural circulation cooled U-battery

    Energy Technology Data Exchange (ETDEWEB)

    De Zwaan, Sieuwert; Kloosterman, Jan Leen [Delft University of Technology, Delft (Netherlands); Van Uitert, Gert [The Hague (Netherlands)

    2008-07-01

    A feasibility study has been performed on a natural circulation cooled small nuclear reactor with a molten salt or tin as a coolant. This reactor is called the U-Battery. The study included neutronics calculations to obtain the minimum dimensions required for a critical system during burnup, the calculation of coolant temperature and core temperature reactivity coefficients, and an investigation of the thermal hydraulics to asses the possibilities for natural circulation cooling. For every coolant, core designs are feasible within the dimensions imposed and with natural circulation of the coolant. (authors)

  20. Analysis on natural circulation capacity of the CARR

    Institute of Scientific and Technical Information of China (English)

    TIAN Wenxi; QIU Suizheng; WANG Jiaqiang; SU Guanghui; JIA Dounan; ZHANG Jianwei

    2007-01-01

    The investigation on natural circulation (NC) characteristics of the China Advanced Research Reactor(CARR) is very valuable for practical engineering application and also a key subject for the CARR. In this study, a computer code was developed to calculate the NC capacity of the CARR under different pool water temperatures. Effects of the pool water temperature on NC characteristics were analyzed. The results show that with increasing pool water temperature, the NC flow rate increases while the NC capacity decreases. Based on the computation results and theoretical deduction, a correlation was proposed on predicting the relationship between the NC mass flow and the core power under different conditions. The correlation prediction agrees well with the computational result within ±10% for the maximal deviation. This work is instructive for the actual operation of the CARR.

  1. Natural Circulation Characteristics at Low-Pressure Conditions through PANDA Experiments and ATHLET Simulations

    Directory of Open Access Journals (Sweden)

    Domenico Paladino

    2008-01-01

    Full Text Available Natural circulation characteristics at low pressure/low power have been studied by performing experimental investigations and numerical simulations. The PANDA large-scale facility was used to provide valuable, high quality data on natural circulation characteristics as a function of several parameters and for a wide range of operating conditions. The new experimental data allow for testing and improving the capabilities of the thermal-hydraulic computer codes to be used for treating natural circulation loops in a range with increased attention. This paper presents a synthesis of a part of the results obtained within the EU-Project NACUSP “natural circulation and stability performance of boiling water reactors.” It does so by using the experimental results produced in PANDA and by showing some examples of numerical simulations performed with the thermal-hydraulic code ATHLET.

  2. Experimental and Analytical Modeling of Natural Circulation and Forced Circulation BWRs : Thermal-Hydraulic, Core-Wide, and Regional Stability Phenomena

    NARCIS (Netherlands)

    Furuya, M.

    2006-01-01

    Currently, 434 nuclear power plants are in operation worldwide. 21% of them are known as Boiling Water Reactors (BWRs). These BWRs have pumps that cool their reactor cores (the forced circulation BWRs). In the design of new BWRs, ways to cool the core by a natural circulation flow, without pumps, al

  3. Experimental and Analytical Modeling of Natural Circulation and Forced Circulation BWRs : Thermal-Hydraulic, Core-Wide, and Regional Stability Phenomena

    NARCIS (Netherlands)

    Furuya, M.

    2006-01-01

    Currently, 434 nuclear power plants are in operation worldwide. 21% of them are known as Boiling Water Reactors (BWRs). These BWRs have pumps that cool their reactor cores (the forced circulation BWRs). In the design of new BWRs, ways to cool the core by a natural circulation flow, without pumps,

  4. Experimental and Analytical Modeling of Natural Circulation and Forced Circulation BWRs : Thermal-Hydraulic, Core-Wide, and Regional Stability Phenomena

    NARCIS (Netherlands)

    Furuya, M.

    2006-01-01

    Currently, 434 nuclear power plants are in operation worldwide. 21% of them are known as Boiling Water Reactors (BWRs). These BWRs have pumps that cool their reactor cores (the forced circulation BWRs). In the design of new BWRs, ways to cool the core by a natural circulation flow, without pumps, al

  5. An efficiency booster for energy conversion in natural circulation loops

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dongqing, E-mail: wangdongqing@stu.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Beijing Computational Science Research Center, Beijing 100084 (China); Jiang, Jin, E-mail: jjiang@eng.uwo.ca [Department of Electrical and Computer Engineering, The University of Western Ontario, London, Ontario N6A 5B9 (Canada); Beijing Computational Science Research Center, Beijing 100084 (China)

    2016-08-01

    Highlights: • Low driving power conversion efficiency of natural circulation loops is proved. • The low conversion efficiency leads to low heat transfer capacity of such loops. • An efficiency booster is designed with turbine to increase the efficiency. • Performance of the proposed booster has been numerically simulated. • The booster drastically enhances heat transfer capacity of such loops. - Abstract: In this paper, the capacity of a natural circulation loop for transferring heat from a heat source to a heat sink has been analyzed. It is concluded that the capacity of the natural circulation loop depends on the conversion efficiency of the thermal energy from the heat source to the driving force for the circulation of the flow. The low conversion efficiency leading to weak driving force in such loops has been demonstrated analytically and validated through simulation results. This issue has resulted in a low heat transfer capacity in the circulation loop. To increase the heat transfer capacity, one has to improve this efficiency. To meet such a need, a novel efficiency booster has been developed in this paper. The booster essentially increases the flow driving force and hence significantly improves the overall heat transfer capacity. Design and analysis of this booster have been performed in detail. The performance has been examined through extensive computer simulations. It is concluded that the booster can indeed drastically improve the heat transfer capacity of the natural circulation loop.

  6. System model of a natural circulation integral test facility

    Science.gov (United States)

    Galvin, Mark R.

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

  7. PWR hot leg natural circulation modeling with MELCOR code

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hong; Lee, Jong In [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1997-12-31

    Previous MELCOR and SCDAP/RELAP5 nodalizations for simulating the counter-current, natural circulation behavior of vapor flow within the RCS hot legs and SG U-tubes when core damage progress can not be applied to the steady state and water-filled conditions during the initial period of accident progression because of the artificially high loss coefficients in the hot legs and SG U-tubes which were chosen from results of COMMIX calculation and the Westinghouse natural circulation experiments in a 1/7-scale facility for simulating steam natural circulation behavior in the vessel and circulation modeling which can be used both for the liquid flow condition at steady state and for the vapor flow condition at the later period of in-vessel core damage. For this, the drag forces resulting from the momentum exchange effects between the two vapor streams in the hot leg was modeled as a pressure drop by pump model. This hot leg natural circulation modeling of MELCOR was able to reproduce similar mass flow rates with those predicted by previous models. 6 refs., 2 figs. (Author)

  8. Influence of Heat Sink and Source Temperature on Operation Reliability of Natural Circulation System%冷源、热源温度对自然循环系统运行可靠性的影响分析

    Institute of Scientific and Technical Information of China (English)

    玉宇; 钱晓明; 高庆瀚; 王晓轩

    2012-01-01

    物理过程失效是导致非能动系统运行失效的重要因素之一,必须在非能动系统可靠性分析中予以考虑.而对于物理过程失效,目前尚无成熟的分析方法.本文提出采用蒙特卡罗模拟方法研究冷源温度、热源温度在其合理范围内变化对自然循环系统运行可靠性的影响.结果表明,冷源、热源温度变化对系统物理过程失效具有重要影响,且运行列数越少,影响越显著.计算结果说明系统运行失效是物理过程失效与设备失效综合作用的结果,但并非二者的简单叠加,物理过程失效与设备失效是互为条件的;当系统设计安全裕量较大时,即使参与运行的设备列数不能满足设计要求,也并不一定导致系统失效.%In the Probabilistic Safety Assessment (PSA), Fault Tree (FT) is the approach commonly used for system reliability analysis. And it is the important feature of passive system and the basic difference from the active system that nuclear plant is able to be driven to safe state or shutdown by inherent safety characters of the reactor and physical principles, and is independent of human interfere or the operations of outside equipments, when the reactor is in the abnormal condition. Therefore, the passive system is widely used in new generation Nuclear Power Plant (NPP), such as AP1000 NPPs and high-temperature gas-cooled reactors to improve the safety. At the same time, since the passive system operation is depending on natural force, both the driven force and resistance are influenced by many uncertain factors, physical process failure become one of the significant causes for the system failure, which need to be considered in, the system reliability analysis. FT method is not power enough to deal with this condition. For the passive system which is operating based on natural circulation, temperature of heat source and sink are important influence factors on system operation. Monte Carlo (MC) simulation is

  9. Development of vapor compression refrigeration cycle with a natural-circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Okazaki, Takashi; Sumida, Yoshihiro; Matsushita, Akihiro

    1999-07-01

    Vapor compression refrigeration cycle with a natural-circulation loop (VCNC) has been developed to save energy for an air conditioner of shelters of electronic facilities. VCNC consists of a compressor, a condenser, a liquid pipe, an evaporator, a gas pipe, an accumulator and three valves. VCNC has two operating modes; vapor compression mode and natural-circulation mode, which are easily changed by the values. The experiments were carried out to evaluate the cycle performance in natural-circulation mode, and calculations were performed to examine the energy consumption of VCNC using the profile of seasonal environmental temperature in Tokyo. The experimental results indicated that the cooling capacity in natural-circulation mode depended on the amount of charged refrigerant and took a maximum value in the case that the refrigerant at the outlet of the evaporator became saturated vapor. Also, the cooling capacity in natural-circulation mode linearly increased as the outdoor temperature decreased. The calculated results indicated that the operating ratio of the compressor of VCNC was approximately 70% smaller than that of conventional air conditioners (VC). Furthermore, the energy consumption of VCNC was approximately 50% lower than that of VC.

  10. Coolant rate distribution in horizontal steam generator under natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Blagovechtchenski, A.; Leontieva, V.; Mitrioukhin, A. [St. Petersburg State Technical Univ. (Russian Federation)

    1997-12-31

    In the presentation the major factors determining the conditions of NCC (Natural Coolant Circulation) in the primary circuit and in particular conditions of coolant rate distribution on the horizontal tubes of PGV-1000 in NPP with VVER-1000 under NCC are considered. 5 refs.

  11. Theoretical investigation on the steady-state natural circulation characteristics of a new type of pressurized water reactor

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This article presents a theoretical investigation on the steady-state natural circulation characteristics of a new type of pressurized water reactor. Through numerically solving the one-dimensional steady-state single-phase conservative equations for the primary circuit and the steady-state two-phase drift-flux conservative equations for the secondary side of the steam generator, the natural circulation characteristics were studied. On the basis of the preliminary calculation analysis, it was found that natural circulation mass flow rate was proportional to the exponential function of the power and that the value of the exponent is related to the operating conditions of the secondary side of the steam generator. The higher the outlet pressure of the secondary side of the steam generator, the higher the primary natural circulation mass flow rate. The larger height difference between the core center and the steam generator center is favorable for the heat removal capacity of the natural circulation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yoder Jr, Graydon L [ORNL; Heatherly, Dennis Wayne [ORNL; Williams, David F [ORNL; Elkassabgi, Yousri M. [Texas A& M University, Kingsville; Caja, Joseph [Electrochemical Systems, Inc.; Caja, Mario [ORNL; Jordan, John [Texas A& M University, Kingsville; Salinas, Roberto [Texas A& M University, Kingsville

    2014-04-01

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

  13. Experimental study of natural circulation flow instability in rectangular channels

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Tao; Qi, Shi; Song, Mingqiang [North China Electric Power Univ., Beijing (China). School of Nuclear Science and Engineering; Passive Nuclear Safety Technology, Beijing (China). Beijing Key Lab.; Xiao, Zejun [Nuclear, Reactor Thermal Hydraulics Technology, Chengdu (China). CNNC Key Lab.

    2017-05-15

    Experiments of natural circulation flow instability were conducted in rectangular channels with 5 mm and 10 mm wide gaps. Results for different heating powers were obtained. The results showed that the flow will tend to be instable with the growing of heating power. The oscillation period of pressure D-value and volume flow are the same, but their phase positions are opposite. They both can be described by trigonometric functions. The existence of edge position and secondary flow will strengthen the disturbance of fluid flow in rectangle channels, which contributes to heat transfer. The disturbance of bubble and fluid will be strengthened, especially in the saturated boiling section, which make it possible for the mixing flow. The results also showed that the resistance in 5 mm channel is bigger than that in 10 mm channel, it is less likely to form stable natural circulation in the subcooled region.

  14. Automated scoping methodology for liquid metal natural circulation small reactor

    Energy Technology Data Exchange (ETDEWEB)

    Son, Hyung M.; Suh, Kune Y., E-mail: kysuh@snu.ac.kr

    2014-07-01

    Highlights: • Automated scoping methodology for natural circulation small modular reactor is developed. • In-house code is developed to carry out system analysis and core geometry generation during scoping. • Adjustment relations are obtained to correct the critical core geometry out of diffusion theory. • Optimized design specification is found using objective function value. • Convex hull volume is utilized to quantify the impact of different constraints on the scope range. - Abstract: A novel scoping method is proposed that can automatically generate design variable range of the natural circulation driven liquid metal cooled small reactor. From performance requirements based upon Generation IV system roadmap, appropriate structure materials are selected and engineering constraints are compiled based upon literature. Utilizing ASME codes and standards, appropriate geometric sizing criteria on constituting components are developed to ensure integrity of the system during its lifetime. In-house one dimensional thermo-hydraulic system analysis code is developed based upon momentum integral model and finite element methods to deal with non-uniform descritization of temperature nodes for convection and thermal diffusion equation of liquid metal coolant. In order to quickly generate critical core dimensions out of given unit cell information, an adjustment relation that relates the critical geometry estimated from one-group diffusion and that from MCNP code is constructed and utilized throughout the process. For the selected unit cell dimension ranges, burnup calculations are carried out to check the cores can generate energy over the reactor lifetime. Utilizing random method, sizing criteria, and in-house analysis codes, an automated scoping methodology is developed. The methodology is applied to nitride fueled integral type lead cooled natural circulation reactor concept to generate design scopes which satisfies given constraints. Three dimensional convex

  15. Single Phase Natural Circulation Behaviors of the Integral Type Marine Reactor Simulator under Rolling Motion Condition

    Directory of Open Access Journals (Sweden)

    Hou-jun Gong

    2015-01-01

    Full Text Available During operation in the sea the reactor natural circulation behaviors are affected by ship rolling motion. The development of an analysis code and the natural circulation behaviors of a reactor simulator under rolling motion are described in this paper. In the case of rolling motion, the primary coolant flow rates in the hot legs and heating channels oscillated periodically, and the amplitude of flow rate oscillation was in direct proportion to rolling amplitude, but in inverse proportion to rolling period. The total mass flow rate also oscillated with half the rolling period, and the average total mass flow rate was less than that in steady state. In the natural circulation under a rolling motion, the flow rate oscillations in the hot legs were controlled by the tangential force; however, the mass flow rate oscillations in the total natural circulation and the heating channels were a result of the combined action of the change of inclination angle, flow resistance, and the extra force arising from the rolling motion. The extra tangential force brought about intense flow rate oscillations in the hot legs, which resulted in increasing total flow resistance; however the extra centrifugal force played a role in increasing thermal driving head.

  16. Development of essential system technologies for advanced reactor - Development of natural circulation analysis code for integral reactor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Goon Cherl; Park, Ik Gyu; Kim, Jae Hak; Lee, Sang Min; Kim, Tae Wan [Seoul National University, Seoul (Korea)

    1999-04-01

    The objective of this study is to understand the natural circulation characteristics of integral type reactors and to develope the natural circulation analysis code for integral type reactors. This study is focused on the asymmetric 3-dimensional flow during natural circulation such as 1/4 steam generator section isolation and the inclination of the reactor systems. Natural circulation experiments were done using small-scale facilities of integral reactor SMART (System-Integrated Modular Advanced ReacTor). CFX4 code was used to investigate the flow patterns and thermal mixing phenomena in upper pressure header and downcomer. Differences between normal operation of all steam generators and the 1/4 section isolation conditions were observed and the results were used as the data 1/4 section isolation conditions were observed and the results were used as the data for RETRAN-03/INT code validation. RETRAN-03 code was modified for the development of natural circulation analysis code for integral type reactors, which was development of natural circulation analysis code for integral type reactors, which was named as RETRAN-03/INT. 3-dimensional analysis models for asymmetric flow in integral type reactors were developed using vector momentum equations in RETRAN-03. Analysis results using RETRAN-03/INT were compared with experimental and CFX4 analysis results and showed good agreements. The natural circulation characteristics obtained in this study will provide the important and fundamental design features for the future small and medium integral reactors. (author). 29 refs., 75 figs., 18 tabs.

  17. Development of essential system technologies for advanced reactor - Development of natural circulation analysis code for integral reactor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Goon Cherl; Park, Ik Gyu; Kim, Jae Hak; Lee, Sang Min; Kim, Tae Wan [Seoul National University, Seoul (Korea)

    1999-04-01

    The objective of this study is to understand the natural circulation characteristics of integral type reactors and to develope the natural circulation analysis code for integral type reactors. This study is focused on the asymmetric 3-dimensional flow during natural circulation such as 1/4 steam generator section isolation and the inclination of the reactor systems. Natural circulation experiments were done using small-scale facilities of integral reactor SMART (System-Integrated Modular Advanced ReacTor). CFX4 code was used to investigate the flow patterns and thermal mixing phenomena in upper pressure header and downcomer. Differences between normal operation of all steam generators and the 1/4 section isolation conditions were observed and the results were used as the data 1/4 section isolation conditions were observed and the results were used as the data for RETRAN-03/INT code validation. RETRAN-03 code was modified for the development of natural circulation analysis code for integral type reactors, which was development of natural circulation analysis code for integral type reactors, which was named as RETRAN-03/INT. 3-dimensional analysis models for asymmetric flow in integral type reactors were developed using vector momentum equations in RETRAN-03. Analysis results using RETRAN-03/INT were compared with experimental and CFX4 analysis results and showed good agreements. The natural circulation characteristics obtained in this study will provide the important and fundamental design features for the future small and medium integral reactors. (author). 29 refs., 75 figs., 18 tabs.

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

    Science.gov (United States)

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

    2016-06-01

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

  19. Thermal analysis of lithium cooled natural circulation loop module for fuel rod testing in the Fast Flux Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Eyler, L.L.; Kim, D.; Stover, R.L.; Beaver, T.R.

    1987-01-01

    Maximum heat removal capability of a lithium cooled natural circulation fuel rod test module design is determined. Loop geometry is optimized within limitations of design specifications for nominal operation temperatures, materials, and test module environment. Results provide test module operation limits and range of potential uncertainties. 3 refs., 12 figs.

  20. Continuous circulation apparatus for air drilling well bore operations

    Energy Technology Data Exchange (ETDEWEB)

    Stallings, J.L.

    1982-02-16

    An apparatus is disclosed for maintaining a continuous supply of air pressure downhole during a well bore drilling operation, even during the addition of a pipe section to the drill string. It consists of a housing installed at the surface of the well at the position of the drilling equipment wherein the upper end of the drill string is separated from the drive mechanism in order that a new piece of drill pipe may be added to the drill string, a flapper or closure member pivotally secured within the housing normally held in an open position by the outer periphery of the drill string and spring urged in a direction toward the open end of the sleeve through which the drive mechanism passes when the drive mechanism has been backed off or removed for the addition of a section of pipe to the drill string, and a by-pass line in communication with the interior of the housing for directing air pressure from the air supply to the housing when the flapper member is in the closed position whereby the air pressure may be circulated downwardly through the drill string for maintaining the air circulation downhole during the entire drilling operation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sebe, F.; Horie, H.; Matsumiya, H. [Toshiba Corporation, 8 Shinsugita-Cho, Isogo-Ku, Yokohama, 235-8523 (Japan); Fanning, T. H. [Argonne National Laboratory, 9700 S Cass Ave, Argonne, IL 60439 (United States)

    2012-07-01

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

  2. Frequency analysis for the thermal hydraulic characterization of a natural circulation circuit

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Walmir M.; Macedo, Luiz A.; Sabundjian, Gaiane; Andrade, Delvonei A.; Umbehaun, Pedro E.; Conti, Thadeu N.; Mesquita, Roberto N.; Masotti, Paulo H.; Angelo, Gabriel, E-mail: wmtorres@ipen.b, E-mail: lamacedo@ipen.b, E-mail: gdjian@ipen.b, E-mail: delvonei@ipen.b, E-mail: umbehaun@ipen.b, E-mail: tnconti@ipen.b, E-mail: , E-mail: rnavarro@ipen.b, E-mail: pmasotti@ipen.b, E-mail: gabriel.angelo@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    This paper presents the frequency analysis studies of the pressure signals from an experimental natural circulation circuit during a heating process. The main objective is to identify the characteristic frequencies of this process using fast Fourier transform. Video images are used to associate these frequencies to the observed phenomenology in the circuit during the process. Sub-cooled and saturated flow boiling, heaters vibrations, overall circuit vibrations, chugging and geysering were observed. Each phenomenon has its specific frequency associated. Some phenomena and their frequencies must be avoided or attenuated since they can cause damages to the natural circulation circuit and its components. Special operation procedures and devices can be developed to avoid these undesirable frequencies. (author)

  3. Experimental and analytical study of stability characteristics of natural circulation boiling water reactors during startup transient

    Science.gov (United States)

    Woo, Kyoungsuk

    Two-phase natural circulation loops are unstable at low pressure operating conditions. New reactor design relying on natural circulation for both normal and abnormal core cooling is susceptible to different types of flow instabilities. In contrast to forced circulation boiling water reactor (BWR), natural circulation BWR is started up without recirculation pumps. The tall chimney placed on the top of the core makes the system susceptible to flashing during low pressure start-up. In addition, the considerable saturation temperature variation may induce complicated dynamic behavior driven by thermal non-equilibrium between the liquid and steam. The thermal-hydraulic problems in two-phase natural circulation systems at low pressure and low power conditions are investigated through experimental methods. Fuel heat conduction, neutron kinetics, flow kinematics, energetics and dynamics that govern the flow behavior at low pressure, are formulated. A dimensionless analysis is introduced to obtain governing dimensionless groups which are groundwork of the system scaling. Based on the robust scaling method and start-up procedures of a typical natural circulation BWR, the simulation strategies for the transient with and without void reactivity feedback is developed. Three different heat-up rates are applied to the transient simulations to study characteristics of the stability during the start-up. Reducing heat-up rate leads to increase in the period of flashing-induced density wave oscillation and decrease in the system pressurization rate. However, reducing the heat-up rate is unable to completely prevent flashing-induced oscillations. Five characteristic regions of stability are discovered at low pressure conditions. They are stable single-phase, flashing near the separator, intermittent oscillation, sinusoidal oscillation and low subcooling stable regions. Stability maps were acquired for system pressures ranging 100 kPa to 400 kPa. According to experimental investigation

  4. Inverted annular flow heat transfer in a natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Ozawa, M.; Umekawa, H.; Shiba, Y.; Yano, T. [Kansai Univ., Osaka (Japan)

    1998-07-01

    Gravity-feed reflooding experiment was conducted in a natural circulation loop of liquid nitrogen. The cooling curve of high temperature tube wall had a characteristic feature, i.e. initial rapid cooling with steam binding, relatively long-time plateau, gradual decrease with or without flow oscillation, and final drastic decrease during quenching process. Such phenomena had close relationship to the heated wall dynamics and heating power transient. To provide fundamental understanding on the present phenomena, the heat transfer data in inverted annular and dispersed flows were obtained under steady or oscillatory flow condition. The experimental data suggested that the heat transfer coefficient in the inverted annular or dispersed flow regimes is a slightly increasing function of heat flux but significantly depended on the tube diameter. The flow oscillation deteriorated heat transfer slightly in the inverted annular and dispersed flow regimes but significantly in the quenching process.

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

    Energy Technology Data Exchange (ETDEWEB)

    Massoud, M

    1987-01-01

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

  6. Experimental Investigation of Natural Circulation in Regional Energy Reactor-10MW{sub th}

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Byeong Il; Jeun, Gyoo Dong [Hanyang University, Seoul (Korea, Republic of); Kim, Moo Hwan [POSTECH, Pohang (Korea, Republic of)

    2009-10-15

    A small- and medium-sized nuclear reactor (SMR) has drawn attention because it is used for multi-purpose applications of desaltination, district heating, ship propulsion and small-scale power generation. The SMR has the virtue of providing for the safety more than a large-sized nuclear reactor. It can be avoidable the occurrence of a large break LOCA because the primary pipes are eliminated. And as the SMR is designed to simplify the geometries and safety systems, uncertainties about the reactor operations are reduced and its safety improves. RERI (Regional Energy Research Institute for Next Generation) is designing REX-10 (Regional Energy Reactor 10 MWth) based on SMART-P. This reactor must improve the enhanced safety because the main purposes of it are small-scale power generation and district heating. From this reason, REX-10 adopts the way to remove heat by natural circulation. And to investigate the natural circulation characteristics of REX-10, we constructed RTF (REX- 10 Test Facility) in RERI. The main aim of this article is to evaluate the natural circulation behavior under various experimental conditions.

  7. Feasibility analysis of the Primary Loop of Pool-Type Natural Circulating Nuclear Reactor Dedicated to Seawater Desalination

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Woonho; Jeong, Yong Hoon [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    In this study, the feasibility of natural circulation was evaluated for the reference plant AHR400 (Advanced Heating Reactor 400MWth). AHR400 is a pool-type desalination-dedicated nuclear reactor. As a consequence, AHR400 has low operating pressure and temperature which provides large safety margin. Removal of the reactor coolant pump from the AHR400 will enforce integrity of the reactor vessel and passive safety feature. Therefore, the study also tried to find out optimized primary loop design to achieve total natural circulation of the coolant. Natural circulation capacity of the primary loop of the desalination dedicated nuclear reactor AHR400 was evaluated. It was concluded that to remove RCP from the AHR400 and operates the reactor only by natural circulation of the coolant is impossible. Decreased core power as half make removal of RCP possible with 15m central height difference between the core and IHXs. Furthermore, validation and modification of pressure loss coefficients by small-scaled natural circulation experiment at a pool-type reactor would provide more accurate results.

  8. Preliminary Study of Single-Phase Natural Circulation for Lab-scaled Molten Salt Application

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Yukyung; Kang, Sarah; Kim, In Guk; Seo, Seok Bin; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of); Park, Seong Dae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Advanced reactors such as MSR (FHR), VHTR and AHTR utilized molten salt as a coolant for efficiency and safety which has advantages in higher heat capacity, lower pumping power and scale compared to liquid metal. It becomes more necessary to study on the characteristics of molten salt. However, due to several characteristics such as high operating temperature, large-scale facility and preventing solidification, satisfying that condition for study has difficulties. Thus simulant fluid was used with scaling method for lab-scale experiment. Scaled experiment enables simulant fluid to simulate fluid mechanics and heat transfer behavior of molten salt on lower operating temperature and reduced scale. In this paper, as a proof test of the scaled experiment, simplified single-phase natural circulation loop was designed in a lab-scale and applied to the passive safety system in advanced reactor in which molten salt is considered as a major coolant of the system. For the application of the improved safety system, prototype was based on the primary loop of the test-scale DRACS, the main passive safety system in FHR, developed at the OSU. For preliminary experiment, single-phase natural circulation under low power was performed. DOWTHERM A and DOWTHERM RP were selected as simulant candidates. Then, study of feasibility with simulant was conducted based on the scaling law for heat transfer characteristics and geometric parameters. Additionally, simulation with MARS code and ANSYS-CFX with the same condition of natural circulation was carried out as verification. For the accurate code simulation, thermo-physical properties of DOWTHERM A and RP were developed and implemented into MARS code. In this study, single-phase natural circulation experiment was performed with simulant oil, DOWTHERM RP, based on the passive safety system of FHR. Feasibility of similarity experiment for molten salt with oil simulant was confirmed by scaling method. In addition, simulation with two

  9. Development of an Internally Circulating Fluidized Bed Membrane Reactor for Hydrogen Production from Natural Gas

    Institute of Scientific and Technical Information of China (English)

    XIE Dong-lai; GRACE John R; LIM C Jim

    2006-01-01

    An innovative Internally Circulating Fluidized Bed Membrane Reactor (ICFBMR) was designed and operated for ultra-pure hydrogen production from natural gas. The reactor includes internal catalyst solids circulation for conveying heat between a reforming zone and an oxidation zone. In the reforming zone, catalyst particles are transported upwards by reactant gas where steam reforming reactions are taking place and hydrogen is permeating through the membrane surfaces. Air is injected into the oxidation zone to generate heat which is carried by catalyst particles to the reforming zone supporting the endothermic steam reforming reaction. The technology development process is introduced: cold model test,pilot plant and industrial demonstration unit. The process flow diagram and key components of each unit are described.The ICFBMR process has the potential to provide improved performance relative to conventional SMR fixed-bed tubular reactors.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Zhiwei [Nuclear Engineering Laboratory Zurich (Switzerland)

    1995-09-01

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

  11. Nature and operation of attitudes.

    Science.gov (United States)

    Ajzen, I

    2001-01-01

    This survey of attitude theory and research published between 1996 and 1999 covers the conceptualization of attitude, attitude formation and activation, attitude structure and function, and the attitude-behavior relation. Research regarding the expectancy-value model of attitude is considered, as are the roles of accessible beliefs and affective versus cognitive processes in the formation of attitudes. The survey reviews research on attitude strength and its antecedents and consequences, and covers progress made on the assessment of attitudinal ambivalence and its effects. Also considered is research on automatic attitude activation, attitude functions, and the relation of attitudes to broader values. A large number of studies dealt with the relation between attitudes and behavior. Research revealing additional moderators of this relation is reviewed, as are theory and research on the link between intentions and actions. Most work in this context was devoted to issues raised by the theories of reasoned action and planned behavior. The present review highlights the nature of perceived behavioral control, the relative importance of attitudes and subjective norms, the utility of adding more predictors, and the roles of prior behavior and habit.

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

    Science.gov (United States)

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

    2015-04-01

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

  13. Isomorphic Operators and Functional Equations for the Skew-Circulant Algebra

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available The skew-circulant matrix has been used in solving ordinary differential equations. We prove that the set of skew-circulants with complex entries has an idempotent basis. On that basis, a skew-cyclic group of automorphisms and functional equations on the skew-circulant algebra is introduced. And different operators on linear vector space that are isomorphic to the algebra of n×n complex skew-circulant matrices are displayed in this paper.

  14. Adaptive fuzzy system for analysis of natural circulation; Sistema fuzzy adaptativo para analise de circulacao natural

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Antonio Cesar Ferreira [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil)

    2002-04-01

    This work consists of the analysis of natural circulation in a thermal hydraulics loop to a system of passive cooling of a nuclear reactor. The loop in reduced scale is similar to a passive heat removal system of a Pressurized Water Reactor. Using some experts of the area and of the system simulator, a set of fuzzy rules are defined to represent the problem and the associated uncertainties. The results are satisfactory if compared for example to experimental ones. With this model, inferences can be accomplished by the engineer, for adjustment and control of the problem variables. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Middleton, Bobby D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rodriguez, Salvador B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Carlson, Matthew David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Mamoru [Purdue Univ., West Lafayette, IN (United State

    2016-11-30

    power density on the flow instability. The experimental startup transient results showed the existence of three different flow instability mechanisms, i.e., flashing instability, condensation induced flow instability, and density wave oscillations. In addition, the void-reactivity feedback did not have significant effects on the flow instability during the startup transients for NMR-50. ii Several initial startup procedures with different power ramp rates were experimentally investigated to eliminate the flow instabilities observed from the startup transients. Particularly, the very slow startup transient and pressurized startup transient tests were performed and compared. It was found that the very slow startup transients by applying very small power density can eliminate the flashing oscillations in the single-phase natural circulation and stabilize the flow oscillations in the phase of net vapor generation. The initially pressurized startup procedure was tested to eliminate the flashing instability during the startup transients as well. The pressurized startup procedure included the initial pressurization, heat-up, and venting process. The startup transient tests showed that the pressurized startup procedure could eliminate the flow instability during the transition from single-phase flow to two-phase flow at low pressure conditions. The experimental results indicated that both startup procedures were applicable to the initial startup of NMR. However, the pressurized startup procedures might be preferred due to short operating hours required. In order to have a deeper understanding of natural circulation flow instability, the quasi-steady tests were performed using the test facility installed with preheater and subcooler. The effect of system pressure, core inlet subcooling, core power density, inlet flow resistance coefficient, and void reactivity feedback were investigated in the quasi-steady state tests. The experimental stability boundaries were determined

  17. Analysis of hot leg natural circulation under station blackout severe accident

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Under severe accidents, natural circulation flows are important to influence the accident progression and result in a pressurized water reactor (PWR). In a station blackout accident with no recovery of steam generator (SG) auxiliary feedwater (TMLB' severe accident scenario), the hot leg countercurrent natural circulation flow is analyzed by using a severe-accident code, to better understand its potential impacts on the creep-rupture timing among the surge line, the hot leg, and SG tubes. The results show that the natural circulation may delay the failure time of the hot leg.The recirculation ratio and the hot mixing factor are also calculated and discussed.

  18. Numerical simulation and artificial neural network modeling of natural circulation boiling water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Garg, A. [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam (India); Sastry, P.S. [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam (India); Pandey, M. [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam (India)]. E-mail: manmohan@iitg.ac.in; Dixit, U.S. [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam (India); Gupta, S.K. [Atomic Energy Regulatory Board, Mumbai 400085 (India)

    2007-02-15

    Numerical simulation of natural circulation boiling water reactor is important in order to study its performance for different designs and under various off-design conditions. Numerical simulations can be performed by using thermal-hydraulic codes. Very fast numerical simulations, useful for extensive parametric studies and for solving design optimization problems, can be achieved by using an artificial neural network (ANN) model of the system. In the present work, numerical simulations of natural circulation boiling water reactor have been performed with RELAP5 code for different values of design parameters and operational conditions. Parametric trends observed have been discussed. The data obtained from these simulations have been used to train artificial neural networks, which in turn have been used for further parametric studies and design optimization. The ANN models showed error within {+-}5% for all the simulated data. Two most popular methods, multilayer perceptron (MLP) and radial basis function (RBF) networks, have been used for the training of ANN model. Sequential quadratic programming (SQP) has been used for optimization.

  19. Experimental Study on Heat Transfer Enhancement of Natural Circulation Liquid Cooling System for Electronic Component

    Institute of Scientific and Technical Information of China (English)

    张正国; 李倩侠; 方晓明; 本田博司

    2004-01-01

    The present research is an experimental study on heat transfer characteristics of a natural circulation cooling system for electronic components. A smooth chip and two micro-pin-finned chips were tested. The chip is mounted on the base of a rectangular horizontal duct located at the bottom of 250 mm high natural circulation loop.FC-72 is used as a coolant. The test conditions are set that the operation pressure of experimental system is 1. 013× 105 Pa, the flow rate of FC-72 is 150 g/min and the subcoolings are 10 K, 25 K and 35 k, respectively. Effect of the subcooling on nucleate boiling and critical heat flux(CHF) were investigated. The results show that subcoolingis found to significantly affect CHF for all chips and micro-pin-finned chips sharply enhanced the boiling heat transfer, CHF of micro-pin-finned chips are 2.5~3 times as large as that of smooth chip at the same subcooling.

  20. Experiments on the basic behavior of supercritical CO{sub 2} natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guangxu [CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology, Nuclear Power Institute of China (China); Huang, Yanping, E-mail: hyanping007@163.com [CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology, Nuclear Power Institute of China (China); Wang, Junfeng; Lv, Fa [CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology, Nuclear Power Institute of China (China); Leung, Laurence K.H. [Canadian Nuclear Laboratories, 286 Plant Road, Chalk River, Ontario (Canada)

    2016-04-15

    Highlights: • Steady-state behavior of supercritical CO{sub 2} natural circulation was studied. • Effects of pressure and inlet temperature were carefully investigated. • No instabilities were found in present study. • The maximum of mass flow was obtained at outlet temperature much higher than T{sub pc}. • Inlet temperature has vital effect on mass flow rate. - Abstract: To study the steady-state characteristics of supercritical carbon dioxide natural circulation, experiments were carried out in a simple rectangular loop with vertically placed heating section. The effects of system pressure and inlet temperature on the system behavior were also investigated. No instabilities were found in the present experiments. The maximum of mass flow rate was obtained at a heating section outlet temperature much higher than the pseudo-critical temperature. The maximum value of mass flow rate increased with system pressure just as in two-phase natural circulation systems. Inlet temperature significantly affected the steady-state characteristics of supercritical carbon dioxide natural circulation system. A small temperature difference of 14 °C in the natural circulation system could induce a mass flow rate with considerably high Re up to 9.1 × 10{sup 4}, which indicates the potential for supercritical carbon dioxide to be used as a high efficient natural circulation working fluid.

  1. [PULMONARY COMPLICATIONS IN CHILDREN, OPERATED ON FOR INBORN HEART FAILURES IN THE ARTIFICIAL BLOOD CIRCULATION ENVIRONMENT].

    Science.gov (United States)

    Moshkivska, L V; Nastenko, E A; Golovenko, O S; Lazoryshynets, V V

    2015-11-01

    The risk factors of pulmonary complications occurrence were analyzed in children, operated on for inborn heart failures in atrificial blood circulation environment. Pulmonary complications rate and the risk factors of their occurrence were analyzed.

  2. Experimental study on natural circulation using liquid nitrogen for superconducting applications

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yeon Suk [Korea Basic Science Institute, Daejeon(Korea, Republic of)

    2013-09-15

    An experiment to investigate the natural circulation of a cryogen has been performed. The study is motivated mainly by our recent development of cryogenic cooling system for prototype superconducting cyclotron without any circulating pump. In the natural circulation loop system, a cooling channel is attached on the outer surface of the aluminium block and the liquid nitrogen passes through inside of the channel to cool the block indirectly. A cryocooler as a heat sink is located at the top to re-condense cryogenic vapor coming from the aluminium block in which electrical heater is installed as a heat source. The main dimensions are determined using the relevant analysis and the natural circulation loop is successfully fabricated. The temperature distributions in the loop are measured during initial cool-down process and in steady state, from which the modified Grashof numbers are calculated and compared with the existing correlation estimated with one-dimensional analysis for steady state flow.

  3. Numerical modeling of supercritical CO{sub 2} natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Archana, V., E-mail: archanav@barc.gov.in [Homi Bhabha National Institute, Mumbai, Maharashtra 400 094 (India); Vaidya, A.M., E-mail: avaidya@barc.gov.in [Bhabha Atomic Research Centre, Mumbai, Maharashtra 400 085 (India); Vijayan, P.K., E-mail: vijayanp@barc.gov.in [Bhabha Atomic Research Centre, Mumbai, Maharashtra 400 085 (India)

    2015-11-15

    Highlights: • Supercritical CO{sub 2} natural circulation loop is modeled by in-house developed 1D and 2D axi-symmetric CFD codes. • Steady state characteristics of VHVC configuration of supercritical CO{sub 2} natural circulation loop are studied over a range of power. • Improved accuracy of predictions by 2D axi-symmetric formulation over 1D formulation is demonstrated. • The validity of correlations used in 1D model such as friction factor and heat transfer correlations is analyzed. • Simulation results shows normal, enhanced and deteriorated heat transfer regimes in supercritical CO{sub 2} natural circulation loop. - Abstract: The objective of this research project is to estimate steady state characteristics of supercritical natural circulation loop (SCNCL) using computational methodology and to compliment on-going experimental investigation of the same at the authors’ organization. For computational investigation, a couple of in-house codes are developed. At first, formulation and a corresponding computer program for the SCNCL based on conservation equations written in 1D framework is developed. Comparison of 1D code results with experimental data showed that, under some operating conditions, there is deviation between computed results and experimental data. To improve predictive capability, it was thought to model the SCNCL using conservation equations in 2D axi-symmetric framework. An existing 2D axi-symmetric code (named NAFA), which was developed and validated for supercritical fluid flow in pipes, is modified for natural circulation loop (NCL) geometry. The modified code, named NAFA-Loop, is subsequently used to compute the steady state characteristics of the SCNCL. These results are compared with experimental data. The steady state characteristics such as the variation of mass flow rate with power, velocity and temperature profiles in heater and cooler are studied using NAFA-Loop. The computed velocity and temperature fields show that the

  4. Experimental studies on heat transfer characteristics and natural circulation performance of PRHRS of the high temperature and high pressure thermal-hydraulic test facility

    Energy Technology Data Exchange (ETDEWEB)

    Park, H. S.; Choi, K. Y.; Joe, S.; Park, C. K.; Lee, S. J.; Song, C. W.; Jeong, M. K. [KAERI, Taejon (Korea, Republic of)

    2003-10-01

    Several experiments are performed to investigate the heat transfer characteristics and natural circulation performance of passive residual removal system (PRHRS) of the high temperature and high pressure thermal-hydraulic test facility. Especially the natural circulation performance of PRHRS, the heat transfer characteristics of PRHRS heat exchangers and emergency cooldown tank (ECT), and the thermal-hydraulic behavior of the primary loop are investigated in detail. The coolant flows steadily in the natural circulation loop which is composed of the steam generator (SG) primary side, the secondary system, and the PRHRS. The heat transfers through the PRHRS heat exchanger and ECT are sufficient enough to enable the natural circulation of the coolant. Also the experimental results show that the core decay heat are sufficiently removed with the operation of the PRHRS.

  5. Self-organizing maps applied to two-phase flow on natural circulation loop studies

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Leonardo F.; Cunha, Kelly de P.; Andrade, Delvonei A.; Sabundjian, Gaiane; Torres, Walmir M.; Macedo, Luiz A.; Rocha, Marcelo da S.; Masotti, Paulo H.F.; Mesquita, Roberto N. de, E-mail: rnavarro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Two-phase flow of liquid and gas is found in many closed circuits using natural circulation for cooling purposes. Natural circulation phenomenon is important on recent nuclear power plant projects for heat removal on 'loss of pump power' or 'plant shutdown' accidents. The accuracy of heat transfer estimation has been improved based on models that require precise prediction of pattern transitions of flow. Self-Organizing Maps are trained to digital images acquired on natural circulation flow instabilities. This technique will allow the selection of the more important characteristics associated with each flow pattern, enabling a better comprehension of each observed instability. This periodic flow oscillation behavior can be observed thoroughly in this facility due its glass-made tubes transparency. The Natural Circulation Facility (Circuito de Circulacao Natural - CCN) installed at Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN, is an experimental circuit designed to provide thermal hydraulic data related to one and two phase flow under natural circulation conditions. (author)

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

    Science.gov (United States)

    Lu, Qiyue

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Buckner, M.R.

    2001-06-26

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

  8. Study on control method of natural circulation by injection of helium gas

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Tetsuaki, E-mail: ttakeda@yamanashi.ac.jp; Nomura, Masashi; Yanagawa, Naoto; Funatani, Shumpei

    2014-05-01

    This study is to investigate a control method of natural circulation of air by injection of helium gas. A depressurization accident is one of the design-basis accidents of a very high temperature reactor (VHTR). When the primary pipe rupture accident occurs in the VHTR, air is expected to enter into the reactor pressure vessel from the breach and oxidize in-core graphite structures. Finally, it seems to be probable that the natural circulation flow of air in the reactor pressure vessel produce continuously. In order to predict or analyze the air ingress phenomena during the depressurization accident of the VHTR, therefore, it is important to develop the method for prevention of air ingress during the accident. The experiment has been carried out regarding natural circulation using a circular tube consisting of a reverse U-shaped type. The vertical channel consists of the one side heated tube and the other side cooled tube. The experimental procedure is as follows. Firstly, the apparatus is filled with air and one vertical tube is heated. Then, natural circulation of air will be produced in the channel. After the steady state is established, a very small amount of helium gas injects from the top of the channel. The velocity, temperature of gas, and temperature of the tube wall are measured during the experiment. The analysis also has been carried out regarding natural circulation. The results were obtained as follows. The temperature difference between the vertical pipes was 50–130 K, and a small amount of helium gas injected to the channel. The volume of injected helium gas is about 3.5–10% of the total volume of the channel. When the temperature difference between the vertical tubes was kept at 52 K, the velocity of natural circulation flow became about 0.12 m/s. During a steady state, a small amount of helium gas injected into the channel. Then, the flow velocity of natural circulation suddenly decreased. The volume of injected helium gas is about 3% of the

  9. Experiments and numerical analysis of a control method for natural circulation through helium gas injection

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Tetsuaki, E-mail: ttakeda@yamanashi.ac.jp; Hatori, Hirofumi; Funatani, Shumpei

    2016-09-15

    This study investigated a control method for natural circulation of air by helium gas injection. A depressurization accident is a design-basis accident of a very high temperature reactor. When a primary pipe rupture accident occurs, air is expected to enter the reactor pressure vessel from the breach. Thus, in-core graphite structures are oxidized. In order to predict and analyze the phenomena of air ingress during a depressurization accident, numerical analysis was carried out using a one-dimensional (1D) analysis code and three-dimensional computational fluid dynamics (3D CFD). An experiment was carried out regarding natural circulation using a circular pipe consisting of a reverse U-shaped channel. The channel consisted of two vertical heated and cooled pipes. The temperature difference between the vertical pipes was maintained at 40–80 K, and a small amount of helium gas was injected into the channel. The injected volume of helium was about 3.1–12.5% of the total channel volume. After injecting helium gas, each component gas moved through molecular diffusion and very weak natural circulation. After approximately 1180 s, ordinary natural circulation of air was suddenly produced. The numerical results of the 3D CFD code were in good agreement with the experimental results. The numerical results also showed that the natural circulation of air can be controlled by helium gas injection.

  10. Simplified thermal-hydraulic analysis of single phase natural circulation circuit with two heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, Larissa Cunha; Su, Jian, E-mail: larissa@lasme.coppe.ufrj.br, E-mail: sujian@lasme.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenhraria Nuclear; Cotta, Renato Machado, E-mail: cotta@mecanica.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (POLI/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Mecanica

    2015-07-01

    Single phase natural circulation circuits composed of two convective heat exchangers and connecting tubes are important for the passive heat removal from spent fuel pools (SFP). To keep the structural integrity of the stored spent fuel assemblies, continuously cooling has to be provided in order to avoid increase at the pool temperature and subsequent uncovering of the fuel and enhanced reaction between water and metal releasing hydrogen. Decay heat can achieve considerably high amounts of energy e.g. in the AP1000, considering the emergency fuel assemblies, the maximum heat decay will reach 13 MW in the 15th day (Westinghouse Electric Company, 2010). A highly efficient alternative to do so is by means of natural circulation, which is cost-effective compared to active cooling systems and is inherently safer since presents less associated devices and no external work is required. Many researchers have investigated safety and stability aspects of natural circulation loops (NCL). However, there is a lack of literature concerning the improvement of NCL through a standard unified methodology, especially for natural circulation circuits with two heat exchangers. In the present study, a simplified thermal-hydraulic analysis of single phase natural circulation circuit with two heat exchanges is presented. Relevant dimensionless key groups were proposed to for the design and safety analysis of a scaled NCL for the cooling of spent fuel storage pool with convective cooling and heating. (author)

  11. Non-dimensional analysis of static bifurcation in a natural circulation loop

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The steady-state characteristics of a two-phase natural circulation loop were investigated based on the homogenous model. Transcendental equations of non-dimensional loop mass flow rate under various conditions were also derived. The static bifurcation diagram of a two-phase natural circulation described with non-dimensional variables Npch-m + was obtained. In addition, various steady-state characteristics of a natural circulation loop were analyzed and discussed. These characteristics include the existence of multiple solutions under certain conditions, and the maximum mass flow rate. The authors also examined the effects of important parameters such as sub-cooling number,riser-to-heated-region length ratio, and riser-to-heated-region diameter ratio.

  12. Analysis of transient gas-liquid two-phase natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Kataoka, Isao; Matsumoto, Tadayoshi; Morita, Yu; Kawashima, Atsushi [Department of Mechanophysics Engineering, Osaka University, Suita, Osaka (Japan); Nakayama, Akio

    1999-07-01

    Analyses were made on the transient behavior of two-phase natural circulation in annular passage. Drift flux model was used in the analyses and several correlations of drift velocity were used and compared. Transient variation of void fraction, inlet liquid flux and length of two-phase region were predicted based on simplified model. It was revealed that in transient two-phase natural circulation, the condition for pressure difference between inlet and outlet is quite important and difficult to be specified. A simplified model for inlet pressure condition was assumed and transient two-phase natural circulation was reasonably predicted. The correlation of drift velocity was shown to have important effect on the flow behavior particularly for the transient variation of two-phase length. (author)

  13. RELAP5 simulation for one and two-phase natural circulation phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Sabundjian, Gaiane; Andrade, Delvonei Alves de; Umbehaun, Pedro Ernesto; Torres, Walmir Maximo; Castro, Alfredo Jose Alvim de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: gdjian@ipen.br; delvonei@ig.com.br; umbehaun@ipen.br; wmtorres@ipen.br; Braz Filho, Francisco A.; Borges, Eduardo Madeira [Centro Tecnico Aeroespacial (CTA-IEAv), Sao Jose dos Campos, SP (Brazil). Inst. de Estudos Avancados]. E-mails: eduardo@ieav.cta.br; fbraz@ieav.cta.br; Belchior Junior, Antonio; Rocha, Ricardo Takeshi Vieira da [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Sao Paulo, SP (Brazil)]. E-mails: belchior@bol.com.br; rtvrocha@uol.com.br; Damy, Osvaldo Luiz Almeida; Torres, Eduardo [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica]. E-mails: osvaldo.damy@poli.usp.br; etorres@pac.ind.br

    2007-07-01

    The objective of this paper is to study the natural circulation phenomenon in one and two-phase regime. There has been a crescent interest in the scientific community in the study of the natural circulation. New generation of compact nuclear reactors uses the natural circulation for residual heat removal in case of accident or shutdown. For this study, the modeling and the simulation of the experimental circuit is performed with the RELAP5 code. The experimental circuit is mounted in the Chemical Engineering Department of the University of Sao Paulo. It is presented in this work the theoretical/experimental comparison for one and two-phase flow. These results will be stored in a database to validate RELAP5 calculations. This work was also used to training some users of RELAP5 from IEAv. (author)

  14. Evaluation of SPACE code for natural circulation test of Hanbit unit 2

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seyun; Kim, Minhee [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    SPACE (Safety and Performance Analysis Code for Nuclear Power Plants) has been developed by KHNP with the cooperation with KEPCO E and C and KAERI. SPACE code is expected to be applied to the safety analysis for LOCA (Loss of Coolant Accident) and Non-LOCA scenarios. SPACE code solves two-fluid, three-field governing equations and programmed with C++ computer language using object-oriented concepts. To evaluate the analysis capability for the passive cooling phenomenon in the actual nuclear power plant, a natural circulation test of Hanbit unit 2 was simulated with SPACE code. To evaluate the analysis capability for the passive cooling phenomenon in the actual nuclear power plant, a natural circulation test of Hanbit unit 2 was simulated with SPACE code. The major parameters of natural circulation in transient are well predicted in SPACE calculations when compared to the plant data. The SPACE code has sufficient capability to simulate passive cooling phenomena.

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

    Science.gov (United States)

    Shi, Shanbin

    The Purdue Novel Modular Reactor (NMR) is a new type small modular reactor (SMR) that belongs to the design of boiling water reactor (BWR). Specifically, the NMR is one third the height and area of a conventional BWR reactor pressure vessel (RPV) with an electric output of 50 MWe. The fuel cycle length of the NMR-50 is extended up to 10 years due to optimized neutronics design. The NMR-50 is designed with double passive engineering safety system. However, natural circulation BWRs (NCBWR) could experience certain operational difficulties due to flow instabilities that occur at low pressure and low power conditions. Static instabilities (i.e. flow excursion (Ledinegg) instability and flow pattern transition instability) and dynamic instabilities (i.e. density wave instability and flashing/condensation instability) pose a significant challenge in two-phase natural circulation systems. In order to experimentally study the natural circulation flow instability, a proper scaling methodology is needed to build a reduced-size test facility. The scaling analysis of the NMR uses a three-level scaling method, which was developed and applied for the design of the Purdue Multi-dimensional Integral Test Assembly (PUMA). Scaling criteria is derived from dimensionless field equations and constitutive equations. The scaling process is validated by the RELAP5 analysis for both steady state and startup transients. A new well-scaled natural circulation test facility is designed and constructed based on the scaling analysis of the NMR-50. The experimental facility is installed with different equipment to measure various thermal-hydraulic parameters such as pressure, temperature, mass flow rate and void fraction. Characterization tests are performed before the startup transient tests and quasi-steady tests to determine the loop flow resistance. The controlling system and data acquisition system are programmed with LabVIEW to realize the real-time control and data storage. The thermal

  16. MODELING THE AMBIENT CONDITION EFFECTS OF AN AIR-COOLED NATURAL CIRCULATION SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Rui; Lisowski, Darius D.; Bucknor, Matthew; Kraus, Adam R.; Lv, Qiuping

    2017-07-02

    The Reactor Cavity Cooling System (RCCS) is a passive safety concept under consideration for the overall safety strategy of advanced reactors such as the High Temperature Gas-Cooled Reactor (HTGR). One such variant, air-cooled RCCS, uses natural convection to drive the flow of air from outside the reactor building to remove decay heat during normal operation and accident scenarios. The Natural convection Shutdown heat removal Test Facility (NSTF) at Argonne National Laboratory (“Argonne”) is a half-scale model of the primary features of one conceptual air-cooled RCCS design. The facility was constructed to carry out highly instrumented experiments to study the performance of the RCCS concept for reactor decay heat removal that relies on natural convection cooling. Parallel modeling and simulation efforts were performed to support the design, operation, and analysis of the natural convection system. Throughout the testing program, strong influences of ambient conditions were observed in the experimental data when baseline tests were repeated under the same test procedures. Thus, significant analysis efforts were devoted to gaining a better understanding of these influences and the subsequent response of the NSTF to ambient conditions. It was determined that air humidity had negligible impacts on NSTF system performance and therefore did not warrant consideration in the models. However, temperature differences between the building exterior and interior air, along with the outside wind speed, were shown to be dominant factors. Combining the stack and wind effects together, an empirical model was developed based on theoretical considerations and using experimental data to correlate zero-power system flow rates with ambient meteorological conditions. Some coefficients in the model were obtained based on best fitting the experimental data. The predictive capability of the empirical model was demonstrated by applying it to the new set of experimental data. The

  17. Experimental study of critical heat flux enhancement with hypervapotron structure under natural circulation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Fangxin [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing (China); Chang, Huajian [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing (China); State Nuclear Power Technology R& D Center (Beijing), Beijing (China); Zhao, Yufeng, E-mail: zhaoyufeng@snptc.com.cn [State Nuclear Power Technology R& D Center (Beijing), Beijing (China); Zhang, Ming; Gao, Tianfang [State Nuclear Power Technology R& D Center (Beijing), Beijing (China); Chen, Peipei [State Power Investment Corporation, Beijing (China)

    2017-05-15

    Highlights: • Natural circulation tests are performed to study the effect of hypervapotron on CHF. • Hypervapotron structure improves CHF under natural circulation conditions. • Visualization data illustrate vapor blanket behavior under subcooled flow conditions. - Abstract: The enhancement of critical heat flux with a hypervapotron structure under natural circulation conditions is investigated in this study. Subcooled flow boiling CHF experiments are performed using smooth and hypervapotron surfaces at different inclination angles under natural circulation conditions. The experimental facility, TESEC (Test of External Vessel Surface with Enhanced Cooling), is designed to conduct CHF experiments in a 30 mm by 61 mm rectangular flow channel with a 200 mm long heated surface along the flow direction. The two-phase flow of subcooled flow boiling on both smooth and hypervapotron heating plates is observed and analyzed by the high-speed visualization technology. The results show that both smooth surface and hypervapotron surface CHF data exhibit a similar trend against inclination angles compared with the CHF results under forced flow condition on the same facility in earlier studies. However, the CHF enhancement of the hypervapotron structure is evidently more significant than the one under forced flow conditions. The experiments also indicate that the natural flow rates are higher with hypervapotron structure. The initiation of CHF is analyzed under transient subcooling and flow rate conditions for both smooth and hypervapotron heating surfaces. An explanation is given for the significant enhancement effect caused by the hypervapotron surface under natural circulation conditions. The visualization data are exhibited to demonstrate the behavior of the vapor blanket at various inclination angles and on different surfaces. The geometric data of the vapor blanket are quantified by an image post-processing method. It is found that the thickness of the vapor blanket

  18. Experimental and numerical stability investigations on natural circulation boiling water reactors

    CERN Document Server

    Marcel, CP

    2007-01-01

    In the design of novel nuclear reactors active systems are replaced by passive ones in order to reduce the risk of failure. For that reason natural circulation is being considered as the primary cooling mechanism in next generation nuclear reactor designs

  19. Experimental and numerical stability investigations on natural circulation boiling water reactors

    NARCIS (Netherlands)

    Marcel, C.P.

    2007-01-01

    The stability of natural circulation boiling water reactors is investigated with a strong emphasis on experiments. Two different facilities are used for such a task: the GENESIS facility (to which a void reactivity feedback system is artificially added) and the CIRCUS facility. In addition, numerica

  20. Experimental and numerical stability investigations on natural circulation boiling water reactors

    NARCIS (Netherlands)

    Marcel, C.P.

    2007-01-01

    The stability of natural circulation boiling water reactors is investigated with a strong emphasis on experiments. Two different facilities are used for such a task: the GENESIS facility (to which a void reactivity feedback system is artificially added) and the CIRCUS facility. In addition, numerica

  1. Experimental and numerical stability investigations on natural circulation boiling water reactors

    NARCIS (Netherlands)

    Marcel, C.P.

    2007-01-01

    The stability of natural circulation boiling water reactors is investigated with a strong emphasis on experiments. Two different facilities are used for such a task: the GENESIS facility (to which a void reactivity feedback system is artificially added) and the CIRCUS facility. In addition,

  2. A RELAP5 study to identify flow regime in natural circulation phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Sabundjian, Gaiane; Torres, Walmir M.; Macedo, Luiz A.; Mesquita, Roberto N.; Andrade, Delvonei A.; Umbehaun, Pedro E.; Conti, Thadeu N.; Masotti, Paulo H.F.; Belchior Junior, Antonio; Angelo, Gabriel, E-mail: gdjian@ipen.b, E-mail: umbehaun@ipen.b, E-mail: wmtorres@ipen.b, E-mail: tnconti@ipen.b, E-mail: rnavarro@ipen.b, E-mail: lamacedo@ipen.b, E-mail: pmasotti@ipen.b, E-mail: abelchior@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    There has been a crescent interest in the scientific community in the study of natural circulation phenomenon. New generation of compact nuclear reactors uses the natural circulation of the fluid as a system of cooling and of residual heat removal in case of accident or shutdown. The objective of this paper is to compare the flow patterns of experimental data and numerical simulation for the natural circulation phenomenon in two-phase flow regime. An experimental circuit built with glass tubes is used for the experiments. Thus, it allows the thermal hydraulic phenomena visualization. There is an electric heater as the heat source, a heat exchanger as the heat sink and an expansion tank to accommodate fluid density excursions. The circuit instrumentation consists of thermocouples and pressure meters to better keep track of the flow and heat transfer phenomena. Data acquisition is performed through a computer interface developed with LABVIEW. The characteristic of the regime is identified using photography techniques. Numerical modeling and simulation is done with the thermal hydraulic code RELAP5, which is widely used for this purpose. This numerical simulation is capable to reproduce some of the flow regimes which are present in the circuit for the natural circulation phenomenon. Comparison between experimental and numerical simulation is presented in this work. (author)

  3. Study on natural circulation characteristics of an IPWR under inclined and rolling condition

    Energy Technology Data Exchange (ETDEWEB)

    He, Lihui [College of Computer Science and Information Technology, Harbin Normal University, Harbin (China); Wang, Bing [Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin (China); Xia, Genglei, E-mail: xiagenglei@163.com [Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin (China); Peng, Minjun [Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin (China)

    2017-06-15

    Highlights: • An ocean-based thermal-hydraulic analysis code was developed based on RELAP5 codes. • The inclination condition can reduce the mass flow rate of reactor core. • The system parameters asymmetry increases with the increasing inclination angle. • Flow oscillation of different loops cancel each other due to the symmetrical arrangement of the reactor. • The off-center roll axis location can break the symmetry and enlarge fluctuation amplitude of the core flow rate. - Abstract: An ocean-based thermal-hydraulic system analysis code was developed based on RELAP5/MOD3 code by adding additional force model of ocean condition and control volume coordinate solver model. The natural circulation operation characteristics of integrated pressurized water reactor (IPWR) under ocean conditions were studied and the effects of inclination and rolling motions were analyzed. The results conclude that, the inclination condition can reduce the mass flow rate of reactor core and lead to inconsistent coolant flow rates of the left and right loops, furthermore, it affects the heat transfer of once-through steam generators (OTSGs). In the case of rolling motion, the additional pressure drop of the loop is dominated by tangential force, and flow oscillation of different loops cancel each other due to the symmetrical arrangement of the reactor. The off-center roll axis location, the combination of the inclination and rolling motion, both can break the thermal-hydraulic symmetry among different loops and enlarge fluctuation amplitude of the core flow rate.

  4. Numerical Simulations and Design Optimization of the PHT Loop of Natural Circulation BWR

    Directory of Open Access Journals (Sweden)

    G. V. Durga Prasad

    2008-01-01

    Full Text Available Mathematical modeling and numerical simulation of natural circulation boiling water reactor (NCBWR are very important in order to study its performance for different designs and various off-design conditions and for design optimization. In the present work, parametric studies of the primary heat transport loop of NCBWR have been performed using lumped parameter models and RELAP5/MOD3.4 code. The lumped parameter models are based on the drift flux model and homogeneous equilibrium mixture (HEM model of two-phase flow. Numerical simulations are performed with both models. Compared to the results obtained from the HEM model, those obtained from the drift flux model are closer to RELAP5. The variations of critical heat flux with various geometric parameters and operating conditions are thoroughly investigated. The material required to construct the primary heat transport (PHT loop of NCBWR has been minimized using sequential quadratic programming. The stability of NCBWR has also been verified at the optimum point.

  5. Circulating miRNAs as biomarkers for oral squamous cell carcinoma recurrence in operated patients

    DEFF Research Database (Denmark)

    Yan, Yan; Wang, Xuan; Venø, Morten Trillingsgaard

    2017-01-01

    MicroRNAs (miRNAs) are small regulatory non-coding RNAs for which altered expression in cancers can serve as potential biomarkers for diseases. We here investigated whether circulating miRNAs can serve as biomarkers for predicting post-operational recurrence of oral squamous cell carcinoma (OSCC)...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-11-01

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

  7. Validation of the RELAP5 code for the modeling of flashing-induced instabilities under natural-circulation conditions using experimental data from the CIRCUS test facility

    Energy Technology Data Exchange (ETDEWEB)

    Kozmenkov, Y. [Helmholtz-Zentrum Dresden-Rossendorf e.V. (FZD), Institute of Safety Research, P.O.B. 510119, D-01324 Dresden (Germany); Institute of Physics and Power Engineering, Obninsk (Russian Federation); Rohde, U., E-mail: U.Rohde@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf e.V. (FZD), Institute of Safety Research, P.O.B. 510119, D-01324 Dresden (Germany); Manera, A. [Paul Scherrer Institute (Switzerland)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer We report about the simulation of flashing-induced instabilities in natural circulation systems. Black-Right-Pointing-Pointer Flashing-induced instabilities are of relevance for operation of pool-type reactors of small power at low pressure. Black-Right-Pointing-Pointer The RELAP5 code is validated against measurement data from natural circulation experiments. Black-Right-Pointing-Pointer The magnitude and frequency of the oscillations were reproduced in good agreement with the measurement data. - Abstract: This paper reports on the use of the RELAP5 code for the simulation of flashing-induced instabilities in natural circulation systems. The RELAP 5 code is intended to be used for the simulation of transient processes in the Russian RUTA reactor concept operating at atmospheric pressure with forced convection of coolant. However, during transient processes, natural circulation with flashing-induced instabilities might occur. The RELAP5 code is validated against measurement data from natural circulation experiments performed within the framework of a European project (NACUSP) on the CIRCUS facility. The facility, built at the Delft University of Technology in The Netherlands, is a water/steam 1:1 height-scaled loop of a typical natural-circulation-cooled BWR. It was shown that the RELAP5 code is able to model all relevant phenomena related to flashing induced instabilities. The magnitude and frequency of the oscillations were reproduced in a good agreement with the measurement data. The close correspondence to the experiments was reached by detailed modeling of all components of the CIRCUS facility including the heat exchanger, the buffer vessel and the steam dome at the top of the facility.

  8. Reliability Assessment of 2400 MWth Gas-Cooled Fast Reactor Natural Circulation Decay Heat Removal in Pressurized Situations

    Directory of Open Access Journals (Sweden)

    C. Bassi

    2008-01-01

    Full Text Available As the 2400 MWth gas-cooled fast reactor concept makes use of passive safety features in combination with active safety systems, the question of natural circulation decay heat removal (NCDHR reliability and performance assessment into the ongoing probabilistic safety assessment in support to the reactor design, named “probabilistic engineering assessment” (PEA, constitutes a challenge. Within the 5th Framework Program for Research and Development (FPRD of the European Community, a methodology has been developed to evaluate the reliability of passive systems characterized by a moving fluid and whose operation is based on physical principles, such as the natural circulation. This reliability method for passive systems (RMPSs is based on uncertainties propagation into thermal-hydraulic (T-H calculations. The aim of this exercise is finally to determine the performance reliability of the DHR system operating in a “passive” mode, taking into account the uncertainties of parameters retained for thermal-hydraulical calculations performed with the CATHARE 2 code. According to the PEA preliminary results, exhibiting the weight of pressurized scenarios (i.e., with intact primary circuit boundary for the core damage frequency (CDF, the RMPS exercise is first focusing on the NCDHR performance at these T-H conditions.

  9. Model prediction of the operating behavior of a circulating fluidized bed boiler

    Institute of Scientific and Technical Information of China (English)

    王勤辉; 骆仲泱; 倪明江; 岑可法

    2002-01-01

    An improved mathematical model for a circulating fluidized bed (CFB) boiler based on the model developed earlier by the authors was applied to simulate the operation of a 12 MW CFB boiler. The influences of the excess air ratio, primary air ratio, coal particle size distribution, coal properties (ash content and volatile content) and Ca/S ratio on the boiler operation were analyzed. The results showed that the model simulation may be applied to the optimum design and economic operation of the CFB boiler.

  10. Model prediction of the operating behavior of a circulating fluidized bed boiler

    Institute of Scientific and Technical Information of China (English)

    王勤辉; 骆仲泱; 倪明江; 岑可法

    2002-01-01

    An improved mathematical model for a circulating fluidized bed (CFB) boiler baaed on the model developed earlier by the authors was applied to simulate the operation of a 12 MW CFB boiler.The influences of the excess air ratio, primary air ratio, coal particle size distribution, coal properties (ash content and volatile content) and Ca/S ratio on the boiler operation were analyzed. The results showed that the model simulation may be applied to the optimum design and economic operation of the CFB boiler.

  11. Study on stability of natural circulation flow in an LMFBR. Pt. 2. Stability of core flow

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Tomonari [Central Research Inst. of Electric Power Industry, Abiko, Chiba (Japan). Abiko Research Lab.

    1997-11-01

    By using an experimental apparatus with water in which the primary loop and the core of an LMFBR were roughly simulated, stability of natural circulation flows in the core has been experimentally evaluated. The following were clarified as a result of the present study: (1) Though a certain and stable flow occurs in the primary loop under a steady state of natural circulation, a chaotic flow or a variant flow in addition to the steady flow arises in some simulated fuel sub-assemblies. The chaotic flow tends to occur in the range of large Reynolds number and large Richardson number. (2) Estimation of the fluctuation supposed as a chaos revealed that it was a high dimensional chaos. (author)

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

    Science.gov (United States)

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

    2011-08-01

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

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

    Science.gov (United States)

    Jain, Rachna

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

  14. Comparison between experimental data and numerical modeling for the natural circulation phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Sabundjian, Gaiane; Andrade, Delvonei A.; Umbehaun, Pedro E.; Torres, Walmir M.; Macedo, Luiz A.; Conti, Thadeu N.; Mesquita, Roberto N.; Massotti, Paulo H.F.; Penha, Rosani M.L.; Silva Filho, Mauro F.; Melo, Gabriel R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: gdjian@ipen.br, e-mail: delvonei@ig.com.br, e-mail: umbehaun@ipen.br, e-mail: wmtorres@ipen.br, e-mail: tnconti@ipen.br, e-mail: rnavarro@ipen.br, e-mail: lamacedo@ipen.br, e-mail: pmasotti@ipen.br, e-mail: rmpenha@ipen.br, e-mail: mauromfs@uol.com; Braz Filho, Francisco A.; Borges, Eduardo M. [Instituto de Estudos Avancados (IEAv), Sao Jose dos Campos, SP (Brazil)], e-mail: eduardo@ieav.cta.br, e-mail: fbraz@ieav.cta.br

    2009-07-01

    There is a crescent interest in the scientific community in the study of natural circulation phenomenon. New generation of compact nuclear reactors uses the natural circulation of the fluid as a system of cooling and of residual heat removal in case of accident or shutdown. The objective of this paper is to present a study through the comparison of experimental data and numerical simulation for the natural circulation phenomenon in one and two-phase flow regime. An experimental circuit built with glass tubes is used for the experiments. Thus, it allows the thermal hydraulic phenomena visualization. There is an electric heater as the heat source, a heat exchanger as the heat sink and an expansion tank to accommodate fluid density excursions. The circuit instrumentation consists of thermocouples and pressure meters to better keep track of the flow and heat transfer phenomena. Instrumentation data acquisition is performed through a computer interface developed with LABVIEW. Previous comparisons were presented. However, in this work pressure transducers were mounted in the heat source outlet and in the expansion tank inlet to allow fluid level variation measures. Numerical modeling and simulation is done with the thermal hydraulic code RELAP5, which is widely used for this purpose. This simulation is capable to reproduce pressure variations, expansion tank level and temperatures measured along the circuit. The observed reverse flow in the circuit is also well represented by model. Comparison between experimental and numerical simulation is presented in this work and showed to be in good agreement. (author)

  15. Analysis of a natural draught tower in the circulation seawater system of nuclear power plant of Laguna Verde; Analisis de una torre de tiro natural en el sistema de agua de circulacion de mar de la central nucleoelectrica Laguna Verde

    Energy Technology Data Exchange (ETDEWEB)

    Tijerina S, F.; Vargas A, A. [Comision Federal de Electricidad, Central Nucleoelectrica Laguna Verde, Subgerencia de Ingenieria, Carretera Veracruz-Medellin Km. 7.5, Veracruz (Mexico)], e-mail: francisco.tijerina@cfe.gob.mx

    2009-10-15

    The analysis of a natural draught tower in open circuit for the cooling system of seawater circulation on the nuclear power plant of Laguna Verde, it is based on conditions of 2027 MWt and 2317 MWt, where the flows of circulation water system hardly vary and whose purpose will be, to cool the seawater circulation. The circulation water system is used as heat drain in main condenser of turbo generator to condense the nuclear vapor. The annual average temperature in the seawater at present is of 26 C to the entrance to circulation water system and it is vary in accordance with the time of year. The mean temperature of leaving of circulation water system to the sea is of 41 C. Having a cooling tower to reduce the entrance temperature to the circulation water system, it improves the efficiency of thermal transfer in condenser, it improves the vacuum in condenser giving more operative margin to avoid condenser losses by air entrances and nuclear power plant shutdowns, as well as for to improve the efficiency of operative balance of nuclear power plant, also it prevents the impact in thermal transfer efficiency in condenser by the climatic change. (Author)

  16. Sealed operation, and circulation and purification of gas in the HARPO TPC

    CERN Document Server

    Frotin, M; Attié, D; Bernard, D; Dauvois, V; Delbart, A; Durand, D; Geerebaert, Y; Legand, S; Magnier, P; Poilleux, P; Semeniouk, I

    2015-01-01

    HARPO is a time projection chamber (TPC) demonstrator of a gamma-ray telescope and polarimeter in the MeV-GeV range, for a future space mission. We present the evolution of the TPC performance over a five month sealed-mode operation, by the analysis of cosmic-ray data, followed by the fast and complete recovery of the initial gas properties using a lightweight gas circulation and purification system.

  17. Closed-loop helium circulation system for actuation of a continuously operating heart catheter pump.

    Science.gov (United States)

    Karabegovic, Alen; Hinteregger, Markus; Janeczek, Christoph; Mohl, Werner; Gföhler, Margit

    2017-06-09

    Currently available, pneumatic-based medical devices are operated using closed-loop pulsatile or open continuous systems. Medical devices utilizing gases with a low atomic number in a continuous closed loop stream have not been documented to date. This work presents the construction of a portable helium circulation addressing the need for actuating a novel, pneumatically operated catheter pump. The design of its control system puts emphasis on the performance, safety and low running cost of the catheter pump. Static and dynamic characteristics of individual elements in the circulation are analyzed to ensure a proper operation of the system. The pneumatic circulation maximizes the working range of the drive unit inside the catheter pump while reducing the total size and noise production.Separate flow and pressure controllers position the turbine's working point into the stable region of the pressure creation element. A subsystem for rapid gas evacuation significantly decreases the duration of helium removal after a leak, reaching subatmospheric pressure in the intracorporeal catheter within several milliseconds. The system presented in the study offers an easy control of helium mass flow while ensuring stable behavior of its internal components.

  18. Estimation of the coolant flow through a natural circulation BWR fuel channel applying and equivalent electrical model

    Energy Technology Data Exchange (ETDEWEB)

    Valle H, J.; Morales S, J. B. [UNAM, DEPFI, Laboratorio de Analisis de Ingenieria de Reactores Nucleares, Campus Morelos en IMTA, Jiutepec, Morelos (Mexico); Espinosa P, G., E-mail: julfi_ig@yahoo.com.m [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco No. 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)

    2010-10-15

    This work presents the design and implementation of an advanced controller for a reduced order model of a BWR reactor core cooled by natural circulating water, which allows real time estimates of coolant flows through fuel assemblies about standard neutron flux strings. Nuclear power plants with boiling water reactors control individual fuel assembly coolant flows by forced circulation using external or internal water pumps and different core support plate orifices. These two elements reduce flow dependency on local channel pressure drops. In BWR reactors using only natural circulation coolant flows, these two elements are not available and therefore individual channel coolant flows are highly dependent in local conditions, such as power distributions and local pressure drops. Therefore it is expected that grater uncertainties in these variables be used during safety, fuel management and other analysis, which in turns may lead to increased operation penalties, such as tighter operating limits. The objective of this work is to asses by computer simulations means to reduce uncertainties in the measurement of fuel assembly coolant flows and eventually the associated penalties. During coolant phase transitions, pressure drops and local power may alter local natural circulation through fuel assemblies and flow estimates can be helped or not by control rod moves. This work presents the construction of an optimal controller for a core flow estimator based on a reduced order model of the coolant going though the reactor vessel components and nuclear core. This model is to be driven by plant signals from standard BWR instrumentation in order to estimate the coolant flows in selected fuel assemblies about a LPRM string. For this purpose an equivalent electrical model has been mathematically developed and numerically tested. The power-flow maps of typical BRW are used as steady state references for this equivalent model. Once these were fully reproduced for steady state

  19. Reduced-scale water test of natural circulation for decay heat removal in loop-type sodium-cooled fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, T., E-mail: murakami@criepi.denken.or.jp [Central Research Institute of Electric Power Industry, 1646 Abiko, Chiba (Japan); Eguchi, Y., E-mail: eguchi@criepi.denken.or.jp [Central Research Institute of Electric Power Industry, 1646 Abiko, Chiba (Japan); Oyama, K., E-mail: kazuhiro_oyama@mfbr.mhi.co.jp [Mitsubishi FBR Systems, Inc., 2-34-17 Jinguumae, Shibuya, Tokyo (Japan); Watanabe, O., E-mail: osamu4_watanabe@mfbr.mhi.co.jp [Mitsubishi FBR Systems, Inc., 2-34-17 Jinguumae, Shibuya, Tokyo (Japan)

    2015-07-15

    Highlights: • The natural circulation characteristics of a loop-type SFR are examined by a water test. • The performance of decay heat removal system is evaluated using a similarity law. • The effects of flow deviation in the parallel piping of a primary loop are clarified. • The reproducibility of the natural circulation test is confirmed. - Abstract: Water tests of a loop-type sodium-cooled fast reactor have been conducted to physically evaluate the natural circulation characteristics. The water test apparatus was manufactured as a 1/10-scale mock-up of the Japan Sodium-Cooled Fast Reactor, which adopts a decay heat removal system (DHRS) utilizing natural circulation. Tests simulating a variety of events and operation conditions clarified the thermal hydraulic characteristics and core-cooling performance of the natural circulation in the primary loop. Operation conditions such as the duration of the pump flow coast-down and the activation time of the DHRS affect the natural circulation characteristics. A long pump flow coast-down cools the upper plenum of the reactor vessel (RV). This causes the loss of the buoyant force in the RV. The test result indicates that a long pump flow coast-down tends to result in a rapid increase in the core temperature because of the loss of the buoyant force. The delayed activation of the DHRS causes a decrease in the natural circulation flow rate and a temperature rise in the RV. Flow rate deviation and a reverse flow appear in the parallel cold-leg piping in some events, which cause thermal stratification in the cold-leg piping. The DHRS prevents the core temperature from fatally rise even for the most severe design-basis event, in which sodium leakage in a secondary loop of the DHRS and the opening failure of a single damper of the air cooler occur simultaneously. In the water test for the case of siphon break in the primary loop, which is one of the design extension conditions, a circulation flow consisting of ascendant

  20. Zhongxian-Wuhan Natural Gas Put into Operation

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ The 1375-kilometer Zhongxian-Wuhan natural gas pipeline was put into operation on November 16 after five years of construction, starting to supply natural gas for commercial users in Central China's Hubei Province one month ahead of schedule.

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

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yeon Suk [Korea Basic Science Institute, 169-148 Gwahak-ro, Yuseong-gu, Daejeon, 305-806 (Korea, Republic of)

    2014-01-29

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

  2. Methodology for studies of natural circulation in closed circuits; Metodologia para estudos de circulacao natural em circuitos fechados

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Rafael de Oliveira Pessoa de

    2009-07-01

    This work presents the results obtained from the analysis of stability of the phenomenon of the natural circulation for one-dimension single-phase flow in a closed loop, by a computer program with the method of finite element. The Navier-Stokes equations in cartesian geometry were used for the balance of mass, momentum and one equation for energy. The formulation has been implemented in a computer code developed at the Nuclear Engineering Institute(IEN-CNEN-RJ) and is now available either for futures analysis or design of nuclear systems. (author)

  3. Elimination of zero sequence circulating current between parallel operating three-level inverters

    DEFF Research Database (Denmark)

    Li, Kai; Wang, Xiaodong; Dong, Zhenhua

    2016-01-01

    In order to suppress the zero sequence circulating currents (ZSCCs) between parallel operating three level voltage source inverters with common AC and DC buses, a common mode voltage reduction PWM (CMVR-PWM) technique and neural point potentials (NPPs) control based method is proposed in this paper...... strategies, ZSCCs between parallel inverters can be eliminated effectively. This strategy has the advantage of without carrier synchronization and can be utilized to parallel operating inverters with different types of filter. Simulation result validate the proposed ZSCC elimination schemes....

  4. Apparatus, components and operating methods for circulating fluidized bed transport gasifiers and reactors

    Energy Technology Data Exchange (ETDEWEB)

    Vimalchand, Pannalal; Liu, Guohai; Peng, Wan Wang

    2015-02-24

    The improvements proposed in this invention provide a reliable apparatus and method to gasify low rank coals in a class of pressurized circulating fluidized bed reactors termed "transport gasifier." The embodiments overcome a number of operability and reliability problems with existing gasifiers. The systems and methods address issues related to distribution of gasification agent without the use of internals, management of heat release to avoid any agglomeration and clinker formation, specific design of bends to withstand the highly erosive environment due to high solid particles circulation rates, design of a standpipe cyclone to withstand high temperature gasification environment, compact design of seal-leg that can handle high mass solids flux, design of nozzles that eliminate plugging, uniform aeration of large diameter Standpipe, oxidant injection at the cyclone exits to effectively modulate gasifier exit temperature and reduction in overall height of the gasifier with a modified non-mechanical valve.

  5. Safety in Liquefied Natural Gas (LNG) Operations

    Energy Technology Data Exchange (ETDEWEB)

    Buhrow, C. [Technische Univ. Bergakademie, Freiberg (Germany). Lehrstuhl Bergbau/Tiefbau; Niemann-Delius, C.; Okafor, E. [Technische Hochschule Aachen (Germany). Lehrstuhl und Inst. fuer Bergbaukunde 3

    2005-07-01

    Germany needs an LNG receiving terminal to import LNG and supplement expected future gas supply shortages. Enormous economic benefits also abound if Germany is to install an LNG receiving terminal. Jobs will be created for several hundred people. New tax revenues will be generated for state and local governments and this will further enhance the economic competitiveness of Germany. Additionally, it will provide Germany with a reliable source of clean-burning energy. Any proposed LNG receiving terminal should incorporate safety right from the start. These safety requirements will: ensure that certain public land uses, people, and structures outside the LNG facility boundaries are protected in the event of LNG fire, prevent vapour clouds associated with an LNG spill from reaching a property line that can be built upon, prevent severe burns resulting from thermal radiation, specify requirements for design, construction and use of LNG facilities and other equipments, and promote safe, secure and reliable LNG operations. The German future LNG business will not be complete without the evolution of both local and international standards that can apply to LNG operations. Currently existing European standards also appear inadequate. With an OHSAS 18001 management system integrated with other existing standards we can better control our LNG occupational health and safety risks, and improve performance in the process. Additionally, an OHSAS 18001 System will help future German LNG contractors and operators safeguard their most important assets - their employees. (orig.)

  6. Changes in equatorial zonal circulations and precipitation in the context of the global warming and natural modes

    Science.gov (United States)

    Kim, Byeong-Hee; Ha, Kyung-Ja

    2017-07-01

    The strengthening and westward shift of Pacific Walker Circulation (PWC) is observed during the recent decades. However, the relative roles of global warming and natural variability on the change in PWC unclearly remain. By conducting numerical atmospheric general circulation model (AGCM) experiments using the spatial SST patterns in the global warming and natural modes which are obtained by the multi-variate EOF analysis from three variables including precipitation, sea surface temperature (SST), and divergent zonal wind, we indicated that the westward shift and strengthening of PWC are caused by the global warming SST pattern in the global warming mode and the negative Interdecadal Pacific Oscillation-like SST pattern in the natural mode. The SST distribution of the Pacific Ocean (PO) has more influence on the changes in equatorial zonal circulations and tropical precipitation than that of the Indian Ocean (IO) and Atlantic Ocean (AO). The change in precipitation is also related to the equatorial zonal circulations variation through the upward and downward motions of the circulations. The IO and AO SST anomalies in the global warming mode can affect on the changes in equatorial zonal circulations, but the influence of PO SST disturbs the changes in Indian Walker Circulation and Atlantic Walker Circulation which are affected by the anomalous SST over the IO and AO. The zonal shift of PWC is found to be highly associated with a zonal gradient of SST over the PO through the idealized numerical AGCM experiments and predictions of CMIP5 models.

  7. The Effect of Circulation Fan on Energy Consumption in Nature Convective Refrigerator-Freezer

    Institute of Scientific and Technical Information of China (English)

    LU Zhi-li; DING Guo-liang

    2007-01-01

    The effect of the circulation fan installed in fresh food compartment on energy consumption of natural convective refrigerator/freezers (RFs) was experimentally studied. Five different RF models with different cycles were tested. The experimental results showed that the energy consumption of the single-loop cycle RF increased by 2.4%~3.8%, that of the bypass two-circuit cycle RF decreased by 1.0%, and that of the two-circuit cycle RF with its evaporators in parallel when the geometry parameters of refrigeration system and the refrigerant charge were not changed after the circulation fan was installed decreased by 3.3%. When the optimization on the refrigerant charge and the evaporator was carried out, the energy consumption of the single-loop cycle RF , the bypass two-circuit cycle RF and the two-circuit cycle RF with its evaporators in parallel, decreased by 1.0%~ 6.4%,3.25% and 3.23% respectively. The present conclusions will provide a guideline to the optimum design for the RF with the circulation fan.

  8. The research of feasible temperature modes in the ampoule channel with natural circulation

    Directory of Open Access Journals (Sweden)

    T.A. Osipova

    2016-03-01

    Full Text Available The paper presents the results of a computational analysis into the thin-wall sample cooling during in-pile irradiation in a two-body ampoule channel with heat transfer by natural convection. A two-body design of the channel makes it possible to change the channel wall heat resistance with the channel heat leak regulation by varying the gas composition and pressure inside the gap between the bodies. The purpose of the study is to determine the feasible sample cooling conditions in the considered channel. The computational analysis was based on a thermal-hydraulic code, RELAP5/MOD3.2. For the calculations, helium and nitrogen were assumed to be the filling gas for the gap between the bodies. Major regularities in the variation of irradiation temperatures have been shown depending on the power density in the channel and irradiation device structural materials, the circulation circuit height, and the channel wall heat resistance. By varying the circulation circuit height and the power density in the structural materials, it is possible to provide inside the ampoule channel the sample cooling temperatures in a range from the circumambient primary coolant temperature to the boiling temperature at a given pressure (50–331°C. With no coolant boiling on samples and with the maximum (8m circulation circuit height, not more than 55kW (14W/g on samples is removed when helium is used as the gap filling gas and not more than 15kW (3.7W/g on samples is removed when nitrogen is used, while, with the minimum (1m circulation circuit height, the respective values are not more than 10kW (2.5W/g on samples and 5kW (1.2W/g on samples.

  9. The simulation of start-up of natural circulation boiler based on the Astrom-Bell model

    Science.gov (United States)

    Zhang, Tianyu; Zhao, Zhenning; Li, Yuanyuan; Zhu, Xianran

    2017-01-01

    This paper presents a numerical investigation on the dynamic analysis of steam and water system of the natural circulation boiler SHL35.2.5/AI with the software MATLAB/SIMULINK. Based on the four-order Astrom-Bell model, a model applicable the specific boiler was established, casting light on the changes in parameters of designed, cold start and varying load condition. And a curve of cold start is obtained, which can be taken as reference for practical operation. In addition, in the condition of varying load, our model captured the phenomenon of false water level, and according analysis is made. Our study introduces a feasible method of simulation on the dynamic analysis of steam and water system on other boilers as well.

  10. Transient analysis of subcritical/supercritical carbon dioxide based natural circulation loop with end heat exchangers: experimental study

    Science.gov (United States)

    Yadav, Ajay Kumar; Ramgopal, Maddali; Bhattacharyya, Souvik

    2017-09-01

    Carbon dioxide (CO2) based natural circulation loops (NCLs) has gained attention due to its compactness with higher heat transfer rate. In the present study, experimental investigations have been carried out to capture the transient behaviour of a CO2 based NCL operating under subcritical as well as supercritical conditions. Water is used as the external fluid in cold and hot heat exchangers. Results are obtained for various inlet temperatures (323-353 K) of water in the hot heat exchanger and a fixed inlet temperature (305 K) of cooling water in the cold heat exchanger. Effect of loop operating pressure (50-90 bar) on system performance is also investigated. Effect of loop tilt in two different planes (XY and YZ) is also studied in terms of transient as well as steady state behaviour of the loop. Results show that the time required to attain steady state decreases as operating pressure of the loop increases. It is also observed that the change in temperature of loop fluid (CO2) across hot or cold heat exchanger decreases as operating pressure increases.

  11. Characteristics of thermal hydraulic stability in a HYPER system with enhanced natural circulation potential

    Energy Technology Data Exchange (ETDEWEB)

    Tak, Nam Il; Park, Won S.; Han, Seok Jung

    1999-06-01

    Pb-Bi eutectic chosen as a coolant of HYPER is an excellent heat transfer medium but requires relatively large pumping power. Thus the mixed cooling concept to increase economy and safety is being considered for HYPER. In this cooling concept, a large fraction of total thermal power is carried by natural circulation. However, the mixed cooling concept has been considered for conceptual designs only an it has never been applied to real reactors. The purpose of the present study is to provide simple tools to analyze mixed flow and to examine fundamental stability characteristics of mixed flow. Conventional one-dimensional approaches using mass, momentum, and energy conservation are used to describe a forced circulating flow affected by a large buoyancy force. The results of simple analysis using preliminary design parameters of HYPER show that cooling by mixed flow is possible only when the total pressure loss of system is sufficiently low. The stability behavior of mixed flow in a simple rectangular loop has been studied using numerical solutions of the governing equations. As in the case of natural circulation, three types of flow regions, such as stable, neutrally stable, and unstable regions, were found. The stability map of mixed flow has been obtained using the results of calculations. Forced flow due to the pump is found to increase the stability of the loop, since the stable portion of the stability map is increased. However, the unstable region of the mixed flow does not completely disappear, even though the pump exists. (author). 37 refs., 4 tabs., 23 figs.

  12. Unsteady single-phase natural circulation flow mixing prediction using CATHARE three-dimensional capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Salah, Anis Bousbia; Vlassenbroeck, Jacques [Bel V - Subsidiary of the Belgian Federal Agency for Nuclear Contro, Brussels (Belize)

    2017-04-15

    Coolant mixing under natural circulation flow regime constitutes a key parameter that may play a role in the course of an accidental transient in a nuclear pressurized water reactor. This issue has motivated some experimental investigations carried out within the OECD/NEA PKL projects. The aim was to assess the coolant mixing phenomenon in the reactor pressure vessel downcomer and the core lower plenum under several asymmetric steady and unsteady flow conditions, and to provide experimental data for code validations. Former studies addressed the mixing phenomenon using, on the one hand, one-dimensional computational approaches with cross flows that are not fully validated under transient conditions and, on the other hand, expensive computational fluid dynamic tools that are not always justified for large-scale macroscopic phenomena. In the current framework, an unsteady coolant mixing experiment carried out in the Rossendorf coolant mixing test facility is simulated using the three-dimensional porous media capabilities of the thermal–hydraulic system CATHARE code. The current study allows highlighting the current capabilities of these codes and their suitability for reproducing the main phenomena occurring during asymmetric transient natural circulation mixing conditions.

  13. Analysis on Non-Uniform Flow in Steam Generator During Steady State Natural Circulation Cooling

    Directory of Open Access Journals (Sweden)

    Susyadi

    2007-07-01

    Full Text Available Investigation on non uniform flow behavior among U-tube in steam generator during natural circulation cooling has been conducted using RELAP5. The investigation is performed by modeling the steam generator into multi channel models, i.e. 9-tubes model. Two situations are implemented, high pressure and low pressure cases. Using partial model, the calculation simulates situation similar to the natural circulation test performed in LSTF. The imposed boundary conditions are flow rate, quality, pressure of the primary side, feed water temperature, steam generator liquid level, and pressure in the secondary side. Calculation result shows that simulation using model with nine tubes is capable to capture important non-uniform phenomena such as reverse flow, fill-and-dump, and stagnant vertical stratification. As a result of appropriate simulation of non uniform flow, the calculated steam generator outlet flow in the primary loop is stable as observed in the experiments. The results also clearly indicate the importance of simulation of non-uniform flow in predicting both the flow stability and heat transfer between the primary and secondary side. In addition, the history of transient plays important role on the selection of the flow distribution among tubes. © 2007 Atom Indonesia. All rights reserved

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

    Energy Technology Data Exchange (ETDEWEB)

    Oktamuliani, Sri, E-mail: srioktamuliani@ymail.com; Su’ud, Zaki, E-mail: szaki@fi.itb.ac.id [Nuclear and Reactor Physics Laboratory, FMIPA, ITB, Physics Buildings, Jl. Ganesha 10, Bandung 40132 (Indonesia)

    2015-09-30

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

  15. Central Hemodynamics and Oxygen Transport in Various Activation of Patients Operated On Under Extracorporeal Circulation

    Directory of Open Access Journals (Sweden)

    Ye. V. Dzybinskaya

    2009-01-01

    Full Text Available Objective: to study central hemodynamics, the determinants of myocardial oxygen balance, and the parameters of oxygen transport in various activation of patients after surgery under extracorporeal circulation. Subjects and methods. Thirty-four patients aged 57.8±2.5 years who had coronary heart disease were divided into 2 groups: 1 those with late activation (artificial ventilation time 157±9 min and 2 those with immediate activation (artificial ventilation time 33±6 min. Group 2 patients were, if required, given fentanyl, midazolam, or myorelaxants. Results. During activation, there were no intergroup differences in the mean levels of the major parameters of cardiac pump function, in the determinants of coronary blood flow (coronary perfusion gradients and myocardial oxygen demand (the product of heart rate by systolic blood pressure, and in the parameters of oxygen transport, including arterial lactatemia. After tracheal extubation, the left ventricular pump coefficient was increased considerably (up to 3.8±0.2 and 4.4±0.2 gm/mm Hg/m2 in Groups 1 and 2, respectively; p<0.05 with minimum inotropic support (dopamine and/or dobutamine being used at 2.7±0.3 and 2.4±0.3 mg/kg/min, respectively. In both groups, there were no close correlations between the indices of oxygen delivery and consumption at all stages of the study, which was indicative of no transport-dependent oxygen uptake. Conclusion. When the early activation protocol was followed up, the maximum acceleration of early activation, including that using specific antagonists of anesthetics, has no negative impact on central hemodynamics, the determinants of myocardial oxygen balance and transport in patients operated on under extracorporeal circulation. Key words: early activation, surgery under extracorporeal circulation, tracheal extubation in the operating-room, central hemodynamics, oxygen transport.

  16. Correlation of Steam Generator Mixing Parameters for Severe Accident Hot-Leg Natural Circulation

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Yehong; Guentay, Salih [Paul Scherrer Institut, Villigen PSI, CH-5232 (Switzerland)

    2008-07-01

    Steam generator inlet plenum mixing phenomenon with hot-leg counter-current natural circulation during a PWR station blackout severe accident is one of the important processes governing which component will fail first as a result of thermal challenge from the circulating gas with high temperature and pressure. Since steam generator tube failure represents bypass release of fission product from the reactor to environment, study of inlet plenum mixing parameters is important to risk analysis. Probability distribution functions of individual mixing parameter should be obtained from experiments or calculated by analysis. In order to perform sensitivity studies of the synergetic effects of all mixing parameters on the severe accident-induced steam generator tube failure, the distribution and correlation of these mixing parameters must be known to remove undue conservatism in thermal-hydraulic calculations. This paper discusses physical laws governing three mixing parameters in a steady state and setups the correlation among these mixing parameters. The correlation is then applied to obtain the distribution of one of the mixing parameters that has not been given in the previous CFD analysis. Using the distributions and considering the inter-dependence of the three mixing parameters, three sensitivity cases enveloping the mixing parameter uncertainties are recommended for the plant analysis. (authors)

  17. Optimal estimate of the coolant flow in the assemblies of a BWR of natural circulation in real time; Estimacion optima del flujo de refrigerante en los ensambles de un BWR de circulacion natural en tiempo real

    Energy Technology Data Exchange (ETDEWEB)

    Valle H, J.; Morales S, J. B. [UNAM, Facultad de Ingenieria, Division de Estudios de Posgrado, Laboratorio de Analisis de Ingenieria de Reactores Nucleares, Paseo Cuauhnahuac 8532, Col. Progreso, 62550 Jiutepec, Morelos (Mexico); Espinosa P, G., E-mail: julfi_jg@yahoo.com.mx [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)

    2012-10-15

    The present work exposes the design and the implementation of an advanced controller that allows estimating the coolant flow in the fuel assemblies of a BWR reactor of natural circulation in real time. To be able to reduce the penalizations that are established in the calculations of the operation limits due to the magnitude of the uncertainties in the coolant flows of a natural circulation reactor, is the objective of this research. In this work the construction of the optimal controller that allows estimating the coolant flows in a fuel channels group of the reactor is shown, as well as the operation of this applied to a reduced order model that simulates the dynamics of a natural circulation reactor. The controller design required of an estimator of the valuation variables not directly of the plant and of the estimates use of the local distributions of the coolant flow. The controller construction of the estimator was based mathematically in the filter Kalman whose algorithm allows to be carried out an advanced control of the system. To prove the estimator operation was development a simplified model that reproduces the basic dynamics of the flowing coolant in the reactor, which works as observer of the system, this model is coupled by means of the estimator controller to a detail model of the plant. The results are presented by means of graphics of the interest variables and the estimate flow, and they are documented in the chart that is presented at the end of this article. (Author)

  18. Estimate of coolant flow in assemblies of a natural circulation BWR applying and equivalent electric model; Estimacion del flujo de refrigerante en los ensambles de un BWR de circulacion natural aplicando un modelo electrico equivalente

    Energy Technology Data Exchange (ETDEWEB)

    Valle H, J.; Morales S, J. B. [UNAM, DEPFI, Laboratorio de Analisis de Ingenieria de Reactores Nucleares, Paseo Cuauhnahuac 8532, 62550 Jiutepec, Morelos (Mexico); Espinosa P, G. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)], e-mail: julfi_jg@yahoo.com.mx

    2009-10-15

    The present work exposes the design and implementation of an advanced controller that it allows to estimate the coolant flow in fuel assemblies of a natural circulation BWR in real time. the complete development of this study is part of a doctoral project in course. In this work the construction of optimal controller is shown that allows to estimate the coolant flows in reactor and its operation applied to an equivalent electric model to natural circulation ESBWR. The controller design that allows the completely automatic starter of natural circulation reactor, required of a variables estimator not meter directly of nuclear power plant and use of local distributions estimates of coolant flow, (this controller type at the moment is utilized in the A BWR and several BWR in operation in Japan). The construction of estimator controller is mathematically based in the theory referring to Kalman filter, whose algorithm provides an advanced control of system. To prove the estimator operation was developed a simplified model that reproduces the basic dynamic of coolant flowing in the ESBWR, a practice way and very interesting of representing this phenomenon is by means the use of an equivalent electric model, which was developed starting from analogies that there is among the relation that keep the pressure differences with the mass flow and differences of electric potential with electric current. A detailed analysis of equivalence among models will be presented in a later article. (Author)

  19. Experimental Study of a Stoppage Natural Circulation during a Nuclear Heating Reactor LOCA

    Institute of Scientific and Technical Information of China (English)

    博金海; 张佑杰; 姜胜耀

    2001-01-01

    The 5MW nuclear heating reactor is an integral naturalcirculation reactor. The rupture of the coolant penetrating tube is a typical accident causing coolant loss. When the water level drops down to the upper edge of the inlet of the heat exchanger, the natural circulation stops. This influences the core cooling and the stability of the main loop. A series of tests showed that there is a stable drop of pressure, and the heated element temperature is not too high to cause burnout. But the backward flow or flow oscillation in the primary coolant circuit occurs when the flow breaks completely in the end. The whole flow process is described and the mechanism is discussed.

  20. Steam drum level control studies of a natural circulation multi loop reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rajesh; Contractor, A.D.; Srivastava, Abhishek; Lele, H.G. [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Reactor Safety Div.; Vaze, K.K. [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Reactor Design and Development Group

    2013-12-15

    The proposed heavy water moderated and light water cooled pressure tube type boiling water reactor works on natural circulation at all power levels. It has parallel inter-connected loops with 452 boiling channels in the main heat transport system configuration. These multiple (four) interconnected loops influence the steam drum level control adversely through the common reactor inlet header. Alternate design studies made earlier for efficient control of SD levels have shown favorable results. This has lead to explore further the present scheme with the compartmentalization of CRIH into four compartments catering to four loops separately. The conventional 3-element level control has been found to be working satisfactorily. The interconnections between ECCS header and inlet header compartments have also increased the safety margin for various LOCA and design basis events. The paper deals with the SD level control aspects for this novel MHT configuration which has been analyzed for various PIEs (Postulated Initiating Events) and found to be satisfactory. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Raussi, P.; Kainulainen, S. [Lappeenranta Univ. of Technology, Lappeenranta (Finland); Kouhia, J. [VTT Energy, Lappeenranta (Finland)

    1995-09-01

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

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

    Science.gov (United States)

    Song, Yu; Four, Aurélien; Baudouy, Bertrand

    2014-01-01

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

  3. Bifurcation and hysteresis phenomena in thetwo-phase natural circulation system

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The static bifurcation of the two-phase natural circulation (TPNC)system was studiedtheoretically and numerically. By the DERPAR algorithm the solutiondiagram was calculated, which shows that the static bifurcationoccurs undersome conditions in the TPNC systems. Also, it shows that, in a region of multiplesolutions, the static instability may occur. It is defined as a region ofthermal-siphon instability induced flow rate jumping. By means of thesolution diagram, the stability margin can be determined in this region.Furthermore, the heat input at the peak of the solution diagram is defined as themaximum capacity of heating load that can be used to judge the capacityof the TPNC ofa given geometry topological structure. Meanwhile, it is interestingthat the TPNCsystemshave the hysteresis phenomenon defined as thermal-siphon hysteresis.Some parametriceffects related were also studied.

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

    Science.gov (United States)

    Egmond, Florike; Kusukawa, Sachiko

    2016-01-01

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

  5. Experimental Investigation of a Natural Circulation Solar Domestic Water Heater Performance under Standard Consumption Rate

    DEFF Research Database (Denmark)

    Kolaei, Alireza Rezania; Taherian, H.; Ganji, D. D.

    2012-01-01

    This paper reports experimental studies on the performance of a natural circulation solar water heater considering the weather condition of a city in north of Iran. The tests are done on clear and partly cloudy days. The variations of storage tank temperature due to consumption from the tank, daily...... consumption influence on the solar water heater efficiency, and on the input temperature of the collector are studied and the delivered daily useful energy has been obtained. The results show that by withdrawing from storage tank, the system as well as its collector efficiency will increase. Considering...... the value of the coefficient FRUL and τα, which are obtained experimentally as 6.03 and 0.83 respectively, average. monthly total load that is covered by this solar water heating system is estimated....

  6. Visualization of boiling flow structure in a natural circulation boiling loop

    Energy Technology Data Exchange (ETDEWEB)

    Karmakar, Arnab; Paruya, Swapan, E-mail: swapanparuya@gmail.com

    2015-04-15

    Highlights: • Vapor–liquid jet flows in natural circulation boiling loop. • Flow patterns and their transitions during geysering instability in the loop. • Evaluation of the efficiency of the needle probe in detecting the vapor–liquid and boiling flow structure. - Abstract: The present study reports vapor–liquid jet flows, flow patterns and their transitions during geysering instability in a natural circulation boiling loop under varied inlet subcooling ΔT{sub sub} (30–50 °C) and heater power Q (4–5 kW). Video imaging, voltage measurement using impedance needle probe, measurement of local pressure and loop flow rate have been carried out in this study. Power spectra of the voltage, the pressure and the flow rate reveal that at a high ΔT{sub sub} the jet flows have long period (21.36–86.95 s) and they are very irregular with a number of harmonics. The period decreases and becomes regular with a decrease of ΔT{sub sub}. The periods of the jet flows at ΔT{sub sub} = 30–50 °C and Q = 4 kW are in close agreement with those obtained from the video imaging. The probe was found to be more efficient than the pressure sensor in detecting the jet flows within an uncertainty of 9.5% and in detecting a variety of bubble classes. Both the imaging and the probe consistently identify the bubbly flow/vapor-mushrooms transition or the bubbly flow/slug flow transition on decreasing ΔT{sub sub} or on increasing Q.

  7. Genetic characterization of small ruminant lentiviruses circulating in naturally infected sheep and goats in Ontario, Canada.

    Science.gov (United States)

    Santry, Lisa A; de Jong, Jondavid; Gold, Alexander C; Walsh, Scott R; Menzies, Paula I; Wootton, Sarah K

    2013-07-01

    Maedi-visna virus (MVV) and caprine arthritis encephalitis virus (CAEV) are related members of a group of small ruminant lentiviruses (SRLVs) that infect sheep and goats. SRLVs are endemic in many countries, including Canada. However, very little is known about the genetic characteristics of Canadian SRLVs, particularly in the province of Ontario. Given the importance of surveillance and eradication programs for the control of SRLVs, it is imperative that the diagnostic tests used to identify infected animals are sensitive to local strains of SRLVs. The aim of this work was to characterize SRLV strains circulating in Ontario and to evaluate the variability of the immunodominant regions of the Gag protein. In this study, the nearly complete gag sequence of 164 SRLVs, from 130 naturally infected sheep and 32 naturally infected goats from Ontario, was sequenced. Animals belonged to distantly located single and mixed species (sheep and goats) farms. Ovine lentiviruses from the same farm tended to cluster more closely together than did caprine lentiviruses from the same farm. Sequence analysis revealed a higher degree of heterogeneity among the caprine lentivirus sequences with an average inter-farm pairwise DNA distance of 10% and only 5% in the ovine lentivirus group. Interestingly, amplification of SRLVs from ELISA positive sheep was successful in 81% of cases, whereas amplification of SRLV proviral DNA was only possible in 55% of the ELISA positive goat samples; suggesting that a significant portion of caprine lentiviruses circulating in Ontario possess heterogeneity at the primer binding sites used in this study. Sequences of sheep and goat SRLVs from Ontario were assembled into phylogenetic trees with other known SRLVs and were found to belong to sequence groups A2 and B1, respectively, as defined by Shah et al. (2004a). A novel caprine lentivirus with a pairwise genetic difference of 15.6-25.4% relative to other group B subtypes was identified. Thus we suggest

  8. Two-phase flow assessment and void fraction measurement of a pilot natural circulation loop using capacitance probe

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Marcelo S.; Cabral, Eduardo L.L., E-mail: msrocha@ipen.br, E-mail: elcabral@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    This article focuses the project, construction and tests of a capacitance probe for void fraction measurement and two-phase flow assessment in a natural circulation loop. Two-phase flow patterns and the associated variables are very important in natural circulation circuits and it is used in the new generation of nuclear reactors for residual heat removal during shut-off and emergency events. The capacitance probe was calibrated to measure the instantaneous bulk void fraction in a vertical tube section of a natural circulation loop. Instantaneous signals generated by the capacitance probe allow the determination of the local bulk void fraction. The probe design is presented and discussed and void fraction data obtained by the probe are compared with theoretical void fraction calculated by analytical models from literature. (author)

  9. Causes of Multiple Organ Dysfunction During Cardiosurgical Operations under Extracorporeal Circulation

    Directory of Open Access Journals (Sweden)

    M. A. Babayev

    2010-01-01

    Full Text Available Objective: to reveal possible causes of postoperative multiple organ dysfunction syndrome (MODS in patients after surgery under extracorporeal circulation (EC, by measuring the level and balance of pro- and anti-inflammatory cytokines. Subjects and methods. The investigation enrolled 162 patients who had undergone operations on the heart and thoracic aorta. The levels of interleukins (IL-6, IL-8, and IL-10 were determined by ELISA. Results. At surgery under EC, MODS was encountered in 5.7%, mortality was 55.6%. The principal causes of MODS were prolonged EC concurrent with bleeding (23%, massive hemorrhage (16%, perioperative myocardial infarction and cardiogenic shock (15%, prolonged EC (12%, acute lung injury (12%, disseminated intravascular coagulation (10%, allergic and anaphylactic reactions (9%, and intravascular hemolysis (6%. The levels of pro- and anti-inflammatory cytokines were substantially increased in all the patients after surgery under EC irrespective of the presence of MODS in the postoperative period. The patients with MODS displayed pro- and anti-inflammatory cytokine imbalance due to a preponderance of the proinflammatory activity of a systemic response. During massive hemorrhage (more than 20 ml/kg, the patients with MODS exhibited a reduction in the two pools of cytokines. In the absence of MODS, there was a parallel increase in both pro- and anti-inflammatory cytokines. The magnitude of a change in the level of cytokines is related to the volume of blood loss. During prolonged EC (more than 170 min, the patients with MODS had a higher pro- and anti-inflammatory cytokine ratio due to the elevated levels of both pools, but the elevation of anti-inflammatory cytokines was more pronounced. In the patients without MODS, the values of both groups of interleukins were sigmficantly unchanged with longer duration of EC. Key words: multiple organ dysfunction syndrome, systemic inflammatory reaction, interleukins 6, 8, 10

  10. Numerical Comparison of Thermalhydraulic Aspects of Supercritical Carbon Dioxide and Subcritical Water-Based Natural Circulation Loop

    Directory of Open Access Journals (Sweden)

    Milan Krishna Singha Sarkar

    2017-02-01

    Full Text Available Application of the supercritical condition in reactor core cooling needs to be properly justified based on the extreme level of parameters involved. Therefore, a numerical study is presented to compare the thermalhydraulic performance of supercritical and single-phase natural circulation loops under low-to-intermediate power levels. Carbon dioxide and water are selected as respective working fluids, operating under an identical set of conditions. Accordingly, a three-dimensional computational model was developed, and solved with an appropriate turbulence model and equations of state. Large asymmetry in velocity and temperature profiles was observed in a single cross section due to local buoyancy effect, which is more prominent for supercritical fluids. Mass flow rate in a supercritical loop increases with power until a maximum is reached, which subsequently corresponds to a rapid deterioration in heat transfer coefficient. That can be identified as the limit of operation for such loops to avoid a high temperature, and therefore, the use of a supercritical loop is suggested only until the appearance of such maxima. Flow-induced heat transfer deterioration can be delayed by increasing system pressure or lowering sink temperature. Bulk temperature level throughout the loop with water as working fluid is higher than supercritical carbon dioxide. This is until the heat transfer deterioration, and hence the use of a single-phase loop is prescribed beyond that limit.

  11. Numerical comparison of thermal hydraulic aspects of supercritical carbon dioxide and subcritical water-based natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Milan Krishna Singhar; Basu, Dipankar Narayan [Dept. of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati (India)

    2017-02-15

    Application of the supercritical condition in reactor core cooling needs to be properly justified based on the extreme level of parameters involved. Therefore, a numerical study is presented to compare the thermalhydraulic performance of supercritical and single-phase natural circulation loops under low-to-intermediate power levels. Carbon dioxide and water are selected as respective working fluids, operating under an identical set of conditions. Accordingly, a three-dimensional computational model was developed, and solved with an appropriate turbulence model and equations of state. Large asymmetry in velocity and temperature profiles was observed in a single cross section due to local buoyancy effect, which is more prominent for supercritical fluids. Mass flow rate in a supercritical loop increases with power until a maximum is reached, which subsequently corresponds to a rapid deterioration in heat transfer coefficient. That can be identified as the limit of operation for such loops to avoid a high temperature, and therefore, the use of a supercritical loop is suggested only until the appearance of such maxima. Flow-induced heat transfer deterioration can be delayed by increasing system pressure or lowering sink temperature. Bulk temperature level throughout the loop with water as working fluid is higher than supercritical carbon dioxide. This is until the heat transfer deterioration, and hence the use of a single-phase loop is prescribed beyond that limit.

  12. Hydrodynamique, transfert de chaleur et combustion de gaz naturel en lit fluidisé circulant Hydrodynamics, Heat Transfer and Combustion of Natural Gas in a Circulating Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Feugier A.

    2006-11-01

    Full Text Available L'hydrodynamique, les transferts de chaleur et la combustion du gaz naturel ont été étudiés dans un réacteur à lit circulant de 15 cm de diamètre et de 7 m de haut. Ce réacteur peut opérer avec des vitesses de gaz allant jusqu'à 15 m/s, jusqu'à des températures de 880-900°C et avec des débits de solides compris entre 0 et 15t/h. Les charges utilisées sont des sables de granulométrie allant de 95 à 625 microns. Le profil de concentration en solides dans le réacteur est déterminé à partir du profil de pression. Une corrélation reliant la vitesse de glissement des particules aux principaux paramètres opératoires, rend compte de façon très satisfaisante de l'ensemble des résultats expérimentaux. La mise en place d'un échangeur en paroi dans la partie supérieure du réacteur a permis la détermination de coefficients d'échange thermique. Ces derniers sont essentiellement fonction de la, concentration en particules au droit de l'échangeur et de la granulométrie des particules. Des valeurs allant jusqu'à 200 W/m2 K peuvent, être obtenues. Enfin, la combustion du méthane s'avère très sensible à la présence de particules dans le réacteur. Ces particules ont un effet inhibiteur. Hydrodynamics, heat transfer and combustion of natural gas have been investigated in a circulating-bed reactor 15 cm in diameter and 7 m high. This reactor can operate with gas velocities up to 15 m/s, at temperature up to 880-900°C and with solids flow rates of between 0 and 15 t/h. The solids used are sands with a particle size ranging from 95 to 625 microns. The solids concentration profile in the reactor is determined from the pressure profile. A correlation linking the slippage velocity of particles to the principal operating parameters very satisfactorily takes into consideration the overall experimental results. The installation of a wall heat exchanger in the upper part of the reactor enabled the heat exchange coefficients to be

  13. Benchmark Simulation of Natural Circulation Cooling System with Salt Working Fluid Using SAM

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, K. K.; Scarlat, R. O.; Hu, R.

    2017-09-03

    Liquid salt-cooled reactors, such as the Fluoride Salt-Cooled High-Temperature Reactor (FHR), offer passive decay heat removal through natural circulation using Direct Reactor Auxiliary Cooling System (DRACS) loops. The behavior of such systems should be well-understood through performance analysis. The advanced system thermal-hydraulics tool System Analysis Module (SAM) from Argonne National Laboratory has been selected for this purpose. The work presented here is part of a larger study in which SAM modeling capabilities are being enhanced for the system analyses of FHR or Molten Salt Reactors (MSR). Liquid salt thermophysical properties have been implemented in SAM, as well as properties of Dowtherm A, which is used as a simulant fluid for scaled experiments, for future code validation studies. Additional physics modules to represent phenomena specific to salt-cooled reactors, such as freezing of coolant, are being implemented in SAM. This study presents a useful first benchmark for the applicability of SAM to liquid salt-cooled reactors: it provides steady-state and transient comparisons for a salt reactor system. A RELAP5-3D model of the Mark-1 Pebble-Bed FHR (Mk1 PB-FHR), and in particular its DRACS loop for emergency heat removal, provides steady state and transient results for flow rates and temperatures in the system that are used here for code-to-code comparison with SAM. The transient studied is a loss of forced circulation with SCRAM event. To the knowledge of the authors, this is the first application of SAM to FHR or any other molten salt reactors. While building these models in SAM, any gaps in the code’s capability to simulate such systems are identified and addressed immediately, or listed as future improvements to the code.

  14. Experimental and computational studies on the natural circulation characteristics of a small- and medium-sized reactor, REX-10

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Byeong Il

    2012-02-15

    obtain key experimental data, thermocouples, turbine flowmeters, and pressure transducer were installed in the proper location of the experimental facilities. The experiments were performed in two categories steady-state and transient experiment. From the steady-state experiment, it was confirmed that the natural circulation flow can be established successfully in both experimental facilities. With regards to the test on the effect of heater power, the heater power is very likely to influence the natural circulation behavior and thereby the mass flow rate tends to follow the natural circulation model proposed by Zvirin et al well. However, it is observed that the feedwater flow rate affects the temperature distribution of the primary system slightly. On the basis of the steady-state experiments, various transient experiments were conducted. The transient experiments showed that two experimental facilities reached new steady-state conditions due to the changes in the heater power and feedwater flow rate. In the case of RTF, the chiller trip experiment was conducted by stopping the feedwater flow. This chiller trip experiment showed that the RTF has the ability to remove the decay heat if the RHRS is normally operated. In NACTER experiment, loss of the feedwater flow rate was tested. This test showed that the NACTER is capable of removing the primary heat of 10kWt despite breakdown of the two pumps. Various transient tests demonstrated that two experimental facilities have the ability to deal with any emergency. To validate MARS, the MARS simulation was conducted. MARS was in good agreement with both steady-state and transient experiments except for two cases . chiller trip in the RTF and loss of the feedwater flow rate in the NACTER. In case of the chiller trip, MARS reached the trip point faster than the experiment and generated the earlier fluctuation of the primary mass flow rate. The reason may be attributed to two facts. First, MARS ignores heat loss to ambient and

  15. Flow visualization of bubble behavior under two-phase natural circulation flow conditions using high speed digital camera

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Wanderley F.; Su, Jian, E-mail: wlemos@con.ufrj.br, E-mail: sujian@lasme.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Faccini, Jose L.H., E-mail: faccini@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. de Termo-Hidraulica Experimental

    2013-07-01

    The The present work aims at identifying flow patterns and measuring interfacial parameters in two-phase natural circulation by using visualization technique with high-speed digital camera. The experiments were conducted in the Natural Circulation Circuit (CCN), installed at Nuclear Engineering Institute/CNEN. The thermo-hydraulic circuit comprises heater, heat exchanger, expansion tank, the pressure relief valve and pipes to interconnect the components. A glass tube is installed at the midpoint of the riser connected to the heater outlet. The natural circulation circuit is complemented by acquisition system of values of temperatures, flow and graphic interface. The instrumentation has thermocouples, volumetric flow meter, rotameter and high-speed digital camera. The experimental study is performed through analysis of information from measurements of temperatures at strategic points along the hydraulic circuit, besides natural circulation flow rates. The comparisons between analytical and experimental values are validated by viewing, recording and processing of the images for the flows patterns. Variables involved in the process of identification of flow regimes, dimensionless parameters, the phase velocity of the flow, initial boiling point, the phenomenon of 'flashing' pre-slug flow type were obtained experimentally. (author)

  16. Estimating steady state and transient characteristics of molten salt natural circulation loop using CFD

    Energy Technology Data Exchange (ETDEWEB)

    Kudariyawar, J.Y. [Homi Bhabha National Institue, Mumbai (India); Vaidya, A.M.; Maheshwari, K.K.; Srivastava, A.K. [Reactor Engineering Division, Bhabha Atomic Research Center, Mumbai (India); Satyamurthy, P. [ATDS, Bhabha Atomic Research Center, Mumbai (India)

    2015-03-15

    The steady state and transient characteristics of a molten salt natural circulation loop (NCL) are obtained by 3D CFD simulations. The working fluid is a mixture of NaNO{sub 3} and KNO{sub 3} in 60:40 ratio. Simulation is performed using PHOENICS CFD software. The computational domain is discretized by a body fitted grid generated using in-built mesh generator. The CFD model includes primary side. Primary side fluid is subjected to heat addition in heater section, heat loss to ambient (in piping connecting heater and cooler) and to secondary side (in cooler section). Reynolds Averaged Navier Stokes equations are solved along with the standard k-ε turbulence model. Validation of the model is done by comparing the computed steady state Reynolds number with that predicted by various correlations proposed previously. Transient simulations were carried out to study the flow initiations transients for different heater powers and different configurations. Similarly the ''power raising'' transient is computed and compared with in-house experimental data. It is found that, using detailed information obtained from 3D transient CFD simulations, it is possible to understand the physics of oscillatory flow patterns obtained in the loop under certain conditions.

  17. Experimental verification of the horizontal steam generator boil-off transfer degradation at natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Hyvaerinen, J. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland); Kouhia, J. [VTT Energy, Lappeenranta (Finland)

    1997-12-31

    The presentation summarises the highlights of experimental results obtained for VVER type horizontal steam generator heat transfer, primary side flow pattern, and mixing in the hot collector during secondary side boil-off with primary at single-phase natural circulation. The experiments were performed using the PACTEL facility with Large Diameter (LD) steam generator models, with collector instrumentation designed specifically for these tests. The key findings are as follows: (1) the primary to secondary heat transfer degrades as the secondary water inventory is depleted, following closely the wetted tube area; (2) a circulatory flow pattern exists in the tube bundle, resulting in reversed flow (from cold to the hot collector) in the lower part of the tube bundle, and continuous flow through the upper part, including the tubes that have already dried out; and (3) mixing of the hot leg flow entering the hot collector and reversed, cold, tube flow remains confined within the collector itself, extending only a row or two above the elevation at which tube flow reversal has taken place. 6 refs.

  18. Natural Number Bias in Operations with Missing Numbers

    Science.gov (United States)

    Christou, Konstantinos P.

    2015-01-01

    This study investigates the hypothesis that there is a natural number bias that influences how students understand the effects of arithmetical operations involving both Arabic numerals and numbers that are represented by symbols for missing numbers. It also investigates whether this bias correlates with other aspects of students' understanding of…

  19. Modeling of natural circulation for the inherent safety analysis of sodium cooled fast reactors

    Directory of Open Access Journals (Sweden)

    A.S. Bochkarev

    2016-12-01

    Full Text Available The paper discusses a set of developed integrated one-dimensional models of thermal-hydraulic processes that contribute to the removal of decay heat in a BN-type reactor. The assumptions and constraints involved in one-dimensional equations of unsteady natural convection in closed circuits have been analyzed. It has been shown that the calculated values of the primary circuit sodium temperature and flow rate in conditions with a loss of heat sink and with a forced circulation of the primary coolant are in a reasonable agreement with the results of a benchmark experiment in the PHENIX reactor. The model makes it possible to assess the effects general thermophysical and geometrical parameters and the selected technology have on the efficiency of passive heat removal by the natural coolant convection in the reactor tank and in the emergency heat removal system's intermediate circuit and by the heat transfer through the reactor vessel. The model is a part of an integrated algorithm used to assess the inherent safety level of advanced fast neutron reactors and is intended primarily to develop, at the early conceptual design stage, the recommendations and requirements with respect to the reactor equipment parameters leading to an increase in the reactor inherent safety. The model will be used to identify the set of quantitative thermal-hydraulic criteria that have an effect on the dynamics of emergency transients leading to a potential loss of integrity by the reactor safety barriers, and to formulate such limits for the defined criteria as would cause, if observed, the requirement for the safety barrier integrity to be met under any combination of the accident initiating events.

  20. The effects of phototherapy on the numbers of circulating natural killer cells and T lymphocytes in psoriasis.

    LENUS (Irish Health Repository)

    Tobin, A M

    2009-04-01

    The innate immune system is believed to be important in the pathogenesis of psoriasis and natural killer (NK) have been found in increased numbers in psoriatic plaques. Alterations in the numbers of NK cells in peripheral blood have been reported. We investigated the effect of phototherapy on levels of peripheral NK cells and lymphocytes in patients with psoriasis. In nine patients whom we followed before, during and after narrowband ultraviolet B (UVB) treatment there were no differences in the numbers of circulating lymphocytes, lymphocyte subsets or cells expressing NK markers and controls. Treatment with narrowband UVB did, however, significantly lower circulating CD4 counts which gradually recovered posttreatment.

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

    Energy Technology Data Exchange (ETDEWEB)

    Jose Reyes

    2005-02-14

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

  2. Design of the Natural Circulation Loop and Implementation of DOWTHERM A Properties into MARS-LMR Code

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Yukyung; Park, Seong Dae; Kang, Sarah; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2015-05-15

    Molten Salt Reactor (MSR), which is one of the generation IV reactors, has an advantage in these requirements. MSR uses a molten salt mixture as the primary coolant, or the fuel itself and it operates on high temperature, so it doesn't need pressurizing. Also, liquid state fuel has an advantage for pyro-processing with easy separation of fission products. These fission products also have relatively short half-lives compared to those of the existing reactors. With these characteristics, MSR can have inherent safety in both direct and indirect sides. Also, MSR can operate at high temperature range, so that it can have the high efficiency to produce electricity. Therefore, research of MSR is meaningful for developing advanced nuclear reactors. FLiBe which is a mixture of lithium fluoride (LiF) and beryllium fluoride (BeF{sub 2}) is used as a primary coolant in MSR and LMR (Liquid Metal cooled Reactor). It has superiority over conventional liquid metal coolant like sodium, because it doesn't react with air or water. thermos-physical properties of DOWTHERM A for MARS-LMR code were made by modifying stg file of existing one. It was based on the process of Moore using 6 output parameters such as specific volume, internal energy, thermal expansion coefficient, isothermal compressibility, specific heat and entropy. With generated stg file (stgdowa.f90) and input file, tpf file (tpfdowa) which includes fluid property tables for MARS-LMR simulation was obtained. For the verification, this tpf file with execution file will be applied to the input deck of our natural circulation design. This work will contribute to researching and developing of MSR and LMR.

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

    Science.gov (United States)

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

    2002-02-01

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

  4. Numerical analysis of the fluid dynamics in a natural circulation loop; Analise numerica da dinamica do escoamento em circuitos de circulacao natural

    Energy Technology Data Exchange (ETDEWEB)

    Angelo, Gabriel

    2013-07-01

    Natural circulation loops apply to many engineering applications such as: water heating solar energy system (thermo-siphons), thermal management of electrical components (voltage converter), geothermal energy, nuclear reactors, etc. In pressurized water nuclear reactors, known as PWR's, the natural circulation loops are employed to ensure passive safety. In critical situations, the heat transfer will occur only by natural convection, without any external control or mechanical devices. This feature is desired and has been considered in modern nuclear reactor projects. This work consists of a numerical study of the natural circulation loop, located at the Instituto de Pesquisas Energeticas e Nucleares / Comissao Nacional de Energia Nuclear in Sao Paulo, Brazil, in order to establish the flow pattern in single phase conditions. The comparison of numerical results to experiments in transient condition revealed significant deviations for the Zero Equation turbulence model. Intermediate deviations for the Eddy Viscosity Turbulence Equation (EVTE), k - {omega}, SST e SSG models. And the best results are obtained by the k - {epsilon} e DES models (with better results for the k - {epsilon} model). (author)

  5. Computational simulation of flow and heat transfer in single-phase natural circulation loops; Simulacao computacional de escoamento e transferencia de calor em circuitos de circulacao natural monofasica

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, Larissa Cunha

    2017-07-01

    Passive decay heat removal systems based on natural circulation are essential assets for the new Gen III+ nuclear power reactors and nuclear spent fuel pools. The aim of the present work is to study both laminar and turbulent flow and heat transfer in single-phase natural circulation systems through computational fluid dynamics simulations. The working fluid is considered to be incompressible with constant properties. In the way, the Boussinesq Natural Convection Hypothesis was applied. The model chosen for the turbulence closure problem was the k -- εThe commercial computational fluid dynamics code ANSYS CFX 15.0 was used to obtain the numerical solution of the governing equations. Two single-phase natural circulation circuits were studied, a 2D toroidal loop and a 3D rectangular loop, both with the same boundary conditions of: prescribed heat flux at the heater and fixed wall temperature at the cooler. The validation and verification was performed with the numerical data provided by DESRAYAUD et al. [1] and the experimental data provided by MISALE et al. [2] and KUMAR et al. [3]. An excellent agreement between the Reynolds number (Re) and the modified Grashof number (Gr{sub m}), independently of Prandtl Pr number was observed. However, the convergence interval was observed to be variable with Pr, thus indicating that Pr is a stability governing parameter for natural circulation. Multiple steady states was obtained for Pr = 0,7. Finally, the effect of inclination was studied for the 3D circuit, both in-plane and out-of-plane inclinations were verified for the steady state laminar regime. As a conclusion, the Re for the out-of-plane inclination was in perfect agreement with the correlation found for the zero inclination system, while for the in-plane inclined system the results differ from that of the corresponding vertical loop. (author)

  6. Thermal-hydraulic characterization of the natural circulation of air between two vertical cylinders enclosed in a rectangular cavity

    Science.gov (United States)

    Alfredo Payan-Rodriguez, Luis; Rivera-Solorio, Carlos Ivan; Villarreal-Garcia, Salvador; Garcia-Cuellar, Alejadro Javier; Ramirez-Tijerina, Ramon

    2008-11-01

    This work presents the results of an experimental analysis focused on the characterization of the natural circulation of air in the vicinity of two vertical cylinders. A three dimensional cavity encloses each cylinder, where one of them is a heat source and the other is a heat sink. A wall with two holes of variable diameter delimits and connects the two enclosures in order to restrict the air flow exchanged between them. The distance between the center lines of the cylinders was varied with the purpose of measuring the effect of the surrounding walls on the natural circulation. All configurations were tested for different heat generation rates. A Particle Image Velocimeter was used to obtain the flow patterns and a set of thermocouples was installed to measure the temperature field. The experimental results are analyzed and discussed.

  7. Inlet throttling effect on the boiling two-phase flow stability in a natural circulation loop with a chimney

    Science.gov (United States)

    Furuya, M.; Inada, F.; Yasuo, A.

    Experiments have been conducted to investigate an effect of inlet restriction on the thermal-hydraulic stability. A Test facility used in this study was designed and constructed to have non-dimensional values that are nearly equal to those of natural circulation BWR. Experimental results showed that driving force of the natural circulation at the stability boundary was described as a function of heat flux and inlet subcooling independent of inlet restriction. In order to extend experimental database regarding thermal-hydraulic stability to different inlet restriction, numerical analysis was carried out based on the homogeneous flow model. Stability maps in reference to the core inlet subcooling and heat flux were presented for various inlet restrictions using the above-mentioned function. Instability region during the inlet subcooling shifted to the higher inlet subcooling with increasing inlet restriction and became larger with increasing heat flux.

  8. A Computing Approach with the Heat-Loss Model for the Transient Analysis of Liquid Metal Natural Circulation Loop

    OpenAIRE

    2014-01-01

    The transient behaviors of natural circulation loop (NCL) are important for the system reliability under postulated accidents. The heat loss and structure thermal inertia may influence the transient behaviors of NCL greatly, so a transient analysis model with consideration of heat loss was developed based on the MATLAB/Simulink to predict the thermal-hydraulic characteristic of liquid metal NCL. The transient processes including the start-up, the loss of pump, and the shutdown of thermal-hydr...

  9. Analysis of the Natural Circulation Behavior in Regional Energy {sub r}X-10MW{sub th}

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Byeong Il [KEPCO Nuclear Fuel Co., Daejeon (Korea, Republic of); Choi, Sun Do [Korea Institute of Nuclear Nonproliferation and Control, Daejeon (Korea, Republic of); Kim, Moo Hwan [Pohang University of Science and Technology, Pohang (Korea, Republic of); Jeun, Gyoo Dong [Hanyang University, Seoul (Korea, Republic of)

    2011-05-15

    Recently there has been a renewal of interest in the Small- and Medium-sized nuclear Reactor (SMR)1-2 such as NHR-200 (China), CAREM (Argentina), IRIS (USA), PSRD-100 (Japan) and SMART (Korea). The SMR has two significant redeeming features various applications and enhanced safety. Firstly, the SMR is used for desalination, district heating, ship propulsion and small-scale power generation. Secondly, in the case of the SMR as the main pipes in the reactor pressure vessel are eliminated and have a simple design, it can avoid a large break loss of coolant accident (LBLOCA). A Regional Energy Research Institute for Next Generation (Redi) is designing a new conceptual nuclear reactor, a Regional Energy {sub r}X-10MW{sub th} (Rex- 10)3 as references of various SMRs. To increase reactor safety, the REX-10 adopts the cooling mode of natural circulation. To evaluate the natural circulation behavior of the REX-10, an experimental facility, NACTER, was designed by scaling down the REX-10. The detailed descriptions of NACTER are in section 2. The main purpose of this article is to evaluate the natural circulation behavior of the REX-10 by the experiment

  10. Circulating pressurized fluidized bed. Trial operation, phase 1c. Final report; Zirkulierende Druckwirbelschicht. Versuchsbetrieb, Phase 1c. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Krein, J.; Schmitt, J.; Wedel, G. von; Winkler, K.

    1993-09-01

    Since March `89, the Deutsche Babcock Energie und Umwelttechnik AG have been operating a 15 MW{sub th} experimental pressurized fluidized bed facility. The plant was first designed as a stationary pressurized fluidized bed and was optimized and tested in a 2000-h period of trial operation. In view of the good results of the plant and the technical superiority of the circulating fluidized bed technology, the experimental facility was converted into a circulating pressurized fluidized bed system. The reconstruction work was started in February `91, and from October `91 onwards the circulating pressurized fluidized bed system was optimized and tested in a 900-h trial operation period. This report explains the concept of circulating pressurized fluidized bed technology as applied by the Deutsche Babcock Energie und Umwelttechnik AG and presents the results of circulating trial operation. The results of circulating and stationary fluidized bed trial operation are compared. This comparison is particularly significant as all marginal systems of the plant, i.e. for combustion air supply, flue gas discharge, coal supply and ash removal, have remained unmodified during the reconstruction phase. (orig.) [Deutsch] Seit Maerz `89 betreibt die Deutsche Babcock Energie und Umwelttechnik AG eine 15 MW{sub th} Druckwirbelschicht Versuchsanlage. In einer ersten Versuchsphase wurde die Anlage als stationaere Druckwirbelschicht konzipiert und in einem 2000-stuendigen Versuchsbetrieb optimiert und getestet. Ausgehend von den guten Ergebnissen aus dem stationaeren, druckaufgeladenen Versuchsbetrieb und in Anbetracht der aus dem atmosphaerischen Bereich bekannten Vorteile der zirkulierenden gegenueber der stationaeren Wirbelschicht wurde die Versuchsanlage ab Februar `91 in eine zirkulierende Druckwirbelschicht umgebaut. Ab Oktober `91 wurde die zirkulierende Druckwirbelschicht in einem 900-stuendigen Versuchsbetrieb optimiert und getestet. In diesem Bericht wird das von der Deutsche

  11. Development of Sirius facility that simulates void-reactivity feedback, and regional and core-wide stability estimation of natural circulation BWR

    Energy Technology Data Exchange (ETDEWEB)

    Furuya, M.; Inada, F.; Yasuo, A. [Tokyo Electric Power Co., Inc., Central Research Institute (Japan)

    2001-07-01

    The SIRIUS facility was designed and constructed for highly accurate simulation of core-wide and regional instabilities of the BWR. A real-time simulation was performed in the digital controller for modal point kinetics of reactor neutronics and fuel-rod conduction on the basis of measured void fractions in reactor core sections of the thermal-hydraulic loop. Stability experiments were conducted for a wide range of fluid conditions, power distributions, and fuel rod thermal conductivity time constants, including the normal operating conditions of a typical natural circulation BWR. The results showed that there is a sufficiently wide stability margin under normal operating conditions, even when void-reactivity feedback is taken into account. (author)

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

    Science.gov (United States)

    Scarlat, Raluca Olga

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

  13. Experimental studies and computational benchmark on heavy liquid metal natural circulation in a full height-scale test loop for small modular reactors

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Yong-Hoon, E-mail: chaotics@snu.ac.kr [Department of Energy Systems Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826 (Korea, Republic of); Cho, Jaehyun [Korea Atomic Energy Research Institute, 111 Daedeok-daero, 989 Beon-gil, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Lee, Jueun; Ju, Heejae; Sohn, Sungjune; Kim, Yeji; Noh, Hyunyub; Hwang, Il Soon [Department of Energy Systems Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826 (Korea, Republic of)

    2017-05-15

    Highlights: • Experimental studies on natural circulation for lead-bismuth eutectic were conducted. • Adiabatic wall boundaries conditions were established by compensating heat loss. • Computational benchmark with a system thermal-hydraulics code was performed. • Numerical simulation and experiment showed good agreement in mass flow rate. • An empirical relation was formulated for mass flow rate with experimental data. - Abstract: In order to test the enhanced safety of small lead-cooled fast reactors, lead-bismuth eutectic (LBE) natural circulation characteristics have been studied. We present results of experiments with LBE non-isothermal natural circulation in a full-height scale test loop, HELIOS (heavy eutectic liquid metal loop for integral test of operability and safety of PEACER), and the validation of a system thermal-hydraulics code. The experimental studies on LBE were conducted under steady state as a function of core power conditions from 9.8 kW to 33.6 kW. Local surface heaters on the main loop were activated and finely tuned by trial-and-error approach to make adiabatic wall boundary conditions. A thermal-hydraulic system code MARS-LBE was validated by using the well-defined benchmark data. It was found that the predictions were mostly in good agreement with the experimental data in terms of mass flow rate and temperature difference that were both within 7%, respectively. With experiment results, an empirical relation predicting mass flow rate at a non-isothermal, adiabatic condition in HELIOS was derived.

  14. The variations of Sylvian veins and cisterns in anterior circulation aneurysms. An operative study.

    Science.gov (United States)

    Aydin, I H; Kadioğlu, H H; Tüzün, Y; Kayaoğlu, C R; Takçi, E

    1996-01-01

    The anatomical variations of Sylvian vein and cistern were investigated during the pterional approach in 230 patients with 276 aneurysms of anterior circulation arteries, that were operated on at the Neurosurgical Department of Atatürk University Medical School. Erzurum, Türkiye. All patients underwent radical surgery for aneurysm by the right or left pterional approach. The findings were recorded during surgical intervention and observed through the slides and videotapes of the operations. In our study, we surgically classified the variations of the Sylvian vein, according to its branching and draining patterns. Type I: The fronto-orbital (frontosylvian), fronto-parietal (parietosylvian) and anterior temporal (temporosylvian) veins drain into one sylvian vein. Type II: Two superficial Sylvian veins with separated basal vein draining into the sphenoparietal and Rosenthal's basal vein. Type III: Two superficial Sylvian veins draining into the sphenoparietal and the superior petrosal veins. Type IV: Hypoplastic superficial Sylvian vein and the deep one. Four types of Sylvian vein variations were defined as follows. The Type I was seen in 45% (n = 103), the Type II was found in 29% (n = 67), Type III was recorded in 15% (n = 34) and Type IV, or hypoplastic and deep form was discovered in 11% (n = 26) of patients. The course of the Sylvian vein was on the temporal side (Temporal Coursing) in 70 percent of the cases (n = 160), on the frontal side (Frontal Coursing) in 19% of the patients (n = 45) and in 8 percent of the cases (n = 18) in the deep localization (Deep Coursing). Only 3 percent of the cases (n = 7) showed a mixed course. The variations of the Sylvian cisterns were classified into three types, according to the relationships between the lateral fronto-orbital gyrus and the superior temporal gyrus. In Sylvian Type, the frontal and temporal lobes are loosely (Sylvian Type A, Large) or tightly (Sylvian Type B, Close and Narrow) approximated on the surface

  15. Deficiencies of Circulating Mucosal-associated Invariant T Cells and Natural Killer T Cells in Patients with Multiple Trauma.

    Science.gov (United States)

    Jo, Young Goun; Choi, Hyun Jung; Kim, Jung Chul; Cho, Young Nan; Kang, Jeong Hwa; Jin, Hye Mi; Kee, Seung Jung; Park, Yong Wook

    2017-05-01

    Mucosal-associated invariant T (MAIT) cells and natural killer T (NKT) cells are known to play important roles in autoimmunity, infectious diseases and cancers. However, little is known about the roles of these invariant T cells in multiple trauma. The purposes of this study were to examine MAIT and NKT cell levels in patients with multiple trauma and to investigate potential relationships between these cell levels and clinical parameters. The study cohort was composed of 14 patients with multiple trauma and 22 non-injured healthy controls (HCs). Circulating MAIT and NKT cell levels in the peripheral blood were measured by flow cytometry. The severity of injury was categorised according to the scoring systems, such as Acute Physiology and Chronic Health Evaluation (APACHE) II score, Simplified Acute Physiology Score (SAPS) II, and Injury Severity Score (ISS). Circulating MAIT and NKT cell numbers were significantly lower in multiple trauma patients than in HCs. Linear regression analysis showed that circulating MAIT cell numbers were significantly correlated with age, APACHE II, SAPS II, ISS category, hemoglobin, and platelet count. NKT cell numbers in the peripheral blood were found to be significantly correlated with APACHE II, SAPS II, and ISS category. This study shows numerical deficiencies of circulating MAIT cells and NKT cells in multiple trauma. In addition, these invariant T cell deficiencies were found to be associated with disease severity. These findings provide important information for predicting the prognosis of multiple trauma. © 2017 The Korean Academy of Medical Sciences.

  16. Energy-Efficient Train Operation Using Nature-Inspired Algorithms

    Directory of Open Access Journals (Sweden)

    Kemal Keskin

    2017-01-01

    Full Text Available A train operation optimization by minimizing its traction energy subject to various constraints is carried out using nature-inspired evolutionary algorithms. The optimization process results in switching points that initiate cruising and coasting phases of the driving. Due to nonlinear optimization formulation of the problem, nature-inspired evolutionary search methods, Genetic Simulated Annealing, Firefly, and Big Bang-Big Crunch algorithms were employed in this study. As a case study a real-like train and test track from a part of Eskisehir light rail network were modeled. Speed limitations, various track alignments, maximum allowable trip time, and changes in train mass were considered, and punctuality was put into objective function as a penalty factor. Results have shown that all three evolutionary methods generated effective and consistent solutions. However, it has also been shown that each one has different accuracy and convergence characteristics.

  17. Lightning: Nature's Probe of Severe Weather for Research and Operations

    Science.gov (United States)

    Blakeslee, R.J.

    2007-01-01

    Lightning, the energetic and broadband electrical discharge produced by thunderstorms, provides a natural remote sensing signal for the study of severe storms and related phenomena on global, regional and local scales. Using this strong signal- one of nature's own probes of severe weather -lightning measurements prove to be straightforward and take advantage of a variety of measurement techniques that have advanced considerably in recent years. We briefly review some of the leading lightning detection systems including satellite-based optical detectors such as the Lightning Imaging Sensor, and ground-based radio frequency systems such as Vaisala's National Lightning Detection Network (NLDN), long range lightning detection systems, and the Lightning Mapping Array (LMA) networks. In addition, we examine some of the exciting new research results and operational capabilities (e.g., shortened tornado warning lead times) derived from these observations. Finally we look forward to the next measurement advance - lightning observations from geostationary orbit.

  18. Circulating concentrations of insulin-like growth factor-1 in dogs with naturally occurring mitral regurgitation

    DEFF Research Database (Denmark)

    Pedersen, Henrik Duelund; Falk, Bo Torkel; Häggström, Jens;

    2005-01-01

    Insulin-like growth factor-1 (IGF-1), which mediates most effects of growth hormone, has effects on cardiac mass and function, and plays an important role in the regulation of vascular tone. In humans, an inverse relationship between degree of heart failure (HF) and circulating IGF-1 concentrations...

  19. A nested Atlantic-Mediterranean Sea general circulation model for operational forecasting

    Directory of Open Access Journals (Sweden)

    P. Oddo

    2009-10-01

    Full Text Available A new numerical general circulation ocean model for the Mediterranean Sea has been implemented nested within an Atlantic general circulation model within the framework of the Marine Environment and Security for the European Area project (MERSEA, Desaubies, 2006. A 4-year twin experiment was carried out from January 2004 to December 2007 with two different models to evaluate the impact on the Mediterranean Sea circulation of open lateral boundary conditions in the Atlantic Ocean. One model considers a closed lateral boundary in a large Atlantic box and the other is nested in the same box in a global ocean circulation model. Impact was observed comparing the two simulations with independent observations: ARGO for temperature and salinity profiles and tide gauges and along-track satellite observations for the sea surface height. The improvement in the nested Atlantic-Mediterranean model with respect to the closed one is particularly evident in the salinity characteristics of the Modified Atlantic Water and in the Mediterranean sea level seasonal variability.

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

    Science.gov (United States)

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

    2016-01-01

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

  1. An Analytical and Experimental Study of a Natural Circulation Loop with Horizontal Heating Section

    Institute of Scientific and Technical Information of China (English)

    YinxueSu; QingjinWu

    1994-01-01

    The thermal performance of a rectangular loop with a horizontal heating segment and a partly cooling vertical leg is studied.By one-dimensional approach,traditional friction factor and empirical correlation,a modified Grashof number Gr* which turns out to be very important in the description of circulation flow is introduced .A new correlation for Nusselt number of the horizontal heater is obtained and the comparison with experimental values shows good agreement.

  2. Numerical Analysis of General Trends in Single-Phase Natural Circulation in a 2D-Annular Loop

    Directory of Open Access Journals (Sweden)

    Gilles Desrayaud

    2008-01-01

    Full Text Available The aim of this paper is to address fluid flow behavior of natural circulation in a 2D-annular loop filled with water. A two-dimensional, numerical analysis of natural convection in a 2D-annular closed-loop thermosyphon has been performed for various radius ratios from 1.2 to 2.0, the loop being heated at a constant flux over the bottom half and cooled at a constant temperature over the top half. It has been numerically shown that natural convection in a 2D-annular closed-loop thermosyphon is capable of showing pseudoconductive regime at pitchfork bifurcation, stationary convective regimes without and with recirculating regions occurring at the entrance of the exchangers, oscillatory convection at Hopf bifurcation and Lorenz-like chaotic flow. The complexity of the dynamic properties experimentally encountered in toroidal or rectangular loops is thus also found here.

  3. Influence of ulinastatin on myocardial enzyme spectrum, inflammatory state and reperfusion injury of patients with extracorporeal circulation heart operation

    Institute of Scientific and Technical Information of China (English)

    Ming-Bin Deng; Ju-Yi Wan; Yi-Bing Fang

    2016-01-01

    Objective:To study the influence of ulinastatin on the myocardial enzymes, the inflammatory state and the reperfusion injury of patients with cardiopulmonary bypass.Methods:A total of 60 patients with extracorporeal circulation heart operation in our hospital from September 2012 to August 2015 were taken as research objects. 60 patients were randomly divided into two groups: observation group (conventional surgery group with ulinastatin, 30 cases) and control group (conventional surgery group, 30 cases), and then detected and compared the related indicators of serum cardiac enzymes, inflammatory state and ischemia-reperfusion injury of two test groups at 12 h, 24 h, 72 h after operation.Results:The serum myocardial zymogram of the observation group at 12 h, 24 h and 72 h after the operation were all lower than those of the control group. Meanwhile, the inflammatory indexes and the reperfusion injury indexes of the observation group were also better than those of the control group. The test result of two groups had significant differences.Conclusions: Ulinastatin can effectively improve the myocardial enzyme spectrum and the inflammatory state of patients with extracorporeal circulation heart operation. Besides, ulinastatin is also plays active role in the prevention of reperfusion injury.

  4. Effect of Loop Diameter on the Steady State and Stability Behaviour of Single-Phase and Two-Phase Natural Circulation Loops

    Directory of Open Access Journals (Sweden)

    P. K. Vijayan

    2008-01-01

    Full Text Available In natural circulation loops, the driving force is usually low as it depends on the riser height which is generally of the order of a few meters. The heat transport capability of natural circulation loops (NCLs is directly proportional to the flow rate it can generate. With low driving force, the straightforward way to enhance the flow is to reduce the frictional losses. A simple way to do this is to increase the loop diameter which can be easily adopted in pressure tube designs such as the AHWR and the natural circulation boilers employed in fossil-fuelled power plants. Further, the loop diameter also plays an important role on the stability behavior. An extensive experimental and theoretical investigation of the effect of loop diameter on the steady state and stability behavior of single- and two-phase natural circulation loops have been carried out and the results of this study are presented in this paper.

  5. A review of modern advances in analyses and applications of single-phase natural circulation loop in nuclear thermal hydraulics

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Dipankar N., E-mail: dipankar.n.basu@gmail.com [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Bhattacharyya, Souvik; Das, P.K. [Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

    2014-12-15

    Highlights: • Comprehensive review of state-of-the-art on single-phase natural circulation loops. • Detailed discussion on growth in solar thermal system and nuclear thermal hydraulics. • Systematic development in scaling methodologies for fabrication of test facilities. • Importance of numerical modeling schemes for stability assessment using 1-D codes. • Appraisal of current trend of research and possible future directions. - Abstract: A comprehensive review of single-phase natural circulation loop (NCL) is presented here. Relevant literature reported since the later part of 1980s has been meticulously surveyed, with occasional obligatory reference to a few pioneering studies originating prior to that period, summarizing the key observations and the present trend of research. Development in the concept of buoyancy-induced flow is discussed, with introduction to flow initiation in an NCL due to instability. Detailed discussion on modern advancement in important application areas like solar thermal systems and nuclear thermal hydraulics are presented, with separate analysis for various reactor designs working on natural circulation. Identification of scaling criteria for designing lab-scale experimental facilities has gone through a series of modification. A systematic analysis of the same is presented, considering the state-of-the-art knowledge base. Different approaches have been followed for modeling single-phase NCLs, including simplified Lorenz system mostly for toroidal loops, 1-D computational modeling for both steady-state and stability characterization and 3-D commercial system codes to have a better flow visualization. Methodical review of the relevant studies is presented following a systematic approach, to assess the gradual progression in understanding of the practical system. Brief appraisal of current research interest is reported, including the use of nanofluids for fluid property augmentation, marine reactors subjected to rolling waves

  6. Conceptual design of a passive moderator cooling system for a pressure tube type natural circulation boiling water cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Mukesh [Reactor Engineering Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Pal, Eshita, E-mail: eshi.pal@gmail.com [Homi Bhabha National Institute, Anushaktinagar, Mumbai 400 094 (India); Nayak, Arun K.; Vijayan, Pallipattu K. [Reactor Engineering Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2015-09-15

    Highlights: • Passive moderator cooling system is designed to cool moderator passively during SBO. • PMCS is a system of two natural circulation loops, coupled via a heat exchanger. • RELAP5 analyses show that PMCS maintains moderator within safe limits for 7 days. - Abstract: The recent Fukushima accident has raised strong concern and apprehensions about the safety of reactors in case of a prolonged Station Black Out (SBO) continuing for several days. In view of this, a detailed study was performed simulating this condition in Advanced Heavy Water Reactor. In this study, a novel concept of moderator cooling by passive means has been introduced in the reactor design. The Passive Moderator Cooling System (PMCS) consists of a shell and tube heat exchanger designed to remove 2 MW heat from the moderator inside Calandria. The heat exchanger is located at a suitable elevation from the Calandria of the reactor, such that the hot moderator rises due to buoyancy into the heat exchanger and upon cooling from shell side water returns to Calandria forming a natural circulation loop. The shell side of the heat exchanger is also a natural circulation loop connected to an overhead large water reservoir, namely the GDWP. The objective of the PMCS is to remove the heat from the moderator in case of an SBO and maintaining its temperature below the permissible safe limit (100 °C) for at least 7 days. The paper first describes the concept of the PMCS. The concept has been assessed considering a prolonged SBO for at least 7 days, through an integrated analysis performed using the code RELAP5/MOD3.2 considering all the major components of the reactor. The analysis shows that the PMCS is able to maintain the moderator temperature below boiling conditions for 7 days.

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

    Science.gov (United States)

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

    2015-09-01

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

  8. CFD Analysis of the Primary Cooling System for the Small Modular Natural Circulation Lead Cooled Fast Reactor SNRLFR-100

    OpenAIRE

    Pengcheng Zhao; Kangli Shi; Shuzhou Li; Jingchao Feng; Hongli Chen

    2016-01-01

    Small modular reactor (SMR) has drawn wide attention in the past decades, and Lead cooled fast reactor (LFR) is one of the most promising advanced reactors which are able to meet the safety economic goals of Gen-IV nuclear energy systems. A small modular natural circulation lead cooled fast reactor-100 MWth (SNRLFR-100) is being developed by University of Science and Technology of China (USTC). In the present work, a 3D CFD model, primary heat exchanger model, fuel pin model, and point kineti...

  9. Numerical simulation of circulation in Kara and Pechora Seas using the system of operational diagnosis and forecast of the marine dynamics

    Science.gov (United States)

    Diansky, Nikolay; Fomin, Vladimir; Kabatchenko, Ilya; Gusev, Anatoly

    2015-04-01

    The system of operational diagnosis and forecast (SODaF) is presented for hydrometeorological characteristics of Kara and Pechora Seas, which is implemented in the N.N.Zubov State Oceanography Institute (SOI). It includes the computation of atmospheric forcing using the WRF model, computation of currents, sea level, temperature, salinity and sea ice using the model INMOM, and computation of wind wave parameters using Russian Wind Wave Model (RWWM).The results of the verification are presented including simulated hydrometeocharacteristics obtained by SODaF for Kara and Pechora Seas. As well, the retrospective simulation was performed for thermohydrodynamical characteristics of these seas for the ice-free period of 2003-2012. The important features of circulation in Kara and Pechora Seas and the structure of water exchange between them in the ice-free period are shown. The use of non-hydrostatic atmospheric model WRF allows one to reproduce katabatic winds formed over the glaciers. In general, the direction and speed of katabatic winds are fairly permanent. In accordance with the nature of katabatic winds, they are intensified from warm to cold period that is well manifested in the wind map for August. The basis of the Kara Sea circulation is NewLand, Yamal and Ob-Yenisey currents, which are well reproduced with the INMOM. It is shown that the main contribution to the monthly mean circulation of Kara and Pechora seas is made by wind currents. In the western part of the Kara Sea between the mainland and the New Land in the fall the pronounced cyclonic circulation is formed that is typical for closed seas. The main components of the circulation are the NewLand and Yamal currents flowing respectively along the eastern coast of NewLand and the western coast of the Yamal Peninsula.It is caused by regional winds directed from the "cold" land to the "warm" sea. In summer,such a circulation is broken along the coast of the mainland, so that the Yamal flow is reduced. This

  10. Slurry circulation after cement compression operations; Circulacao de pasta apos operacoes de compressao de cimento

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Clavio Roberto S. [PETROBRAS, BA (Brazil). Regiao de Producao da Bahia. Divisao Regional de Complementacao

    1994-07-01

    In the traditional low pressure cement compression method, after pressure stabilization we wait for the setting and remove the hardened cement with a rock bit. The method described here suggests that following pressure stabilization, the slurry must be removed from the casing with reverse circulation, thus excluding the whole process of cutting hardened cement, optimizing rig time and equipment wear, and anticipating oil production. This work describes this experience in Reconcavo basin, Potiguar basin, and Campos basin, production regions of PETROBRAS, and suggests slurry parameters and a methodology to employ the method. (author)

  11. Nature on the Move: The Value and Circulation of Liquid Nature and the Emergence of Fictitious Conservation

    NARCIS (Netherlands)

    B.E. Büscher (Bram)

    2013-01-01

    markdownabstract__Abstract__ A rich body of literature investigates the many ways in which nature is impacted upon and transformed by the “endless accumulation of capital.” Much less attention has been reserved for understanding how capitalist actors increasingly aim to profit from the non-extracti

  12. CFD Analysis of the Primary Cooling System for the Small Modular Natural Circulation Lead Cooled Fast Reactor SNRLFR-100

    Directory of Open Access Journals (Sweden)

    Pengcheng Zhao

    2016-01-01

    Full Text Available Small modular reactor (SMR has drawn wide attention in the past decades, and Lead cooled fast reactor (LFR is one of the most promising advanced reactors which are able to meet the safety economic goals of Gen-IV nuclear energy systems. A small modular natural circulation lead cooled fast reactor-100 MWth (SNRLFR-100 is being developed by University of Science and Technology of China (USTC. In the present work, a 3D CFD model, primary heat exchanger model, fuel pin model, and point kinetic model were established based on some reasonable simplifications and assumptions, the steady-state natural circulation characteristics of SNCLFR-100 primary cooling system were discussed and illustrated, and some reasonable suggestions were proposed for the reactor’s thermal-hydraulic and structural design. Moreover, in order to have a first evaluation of the system behavior in accident conditions, an unprotected loss of heat sink (ULOHS transient simulation at beginning of the reactor cycle (BOC has been analyzed and discussed based on the steady-state simulation results. The key temperatures of the reactor core are all under the safety limits at transient state; the reactor has excellent thermal-hydraulic performance.

  13. Investigation of TASS/SMR Capability to Predict a Natural Circulation in the Test Facility for an Integral Reactor

    Directory of Open Access Journals (Sweden)

    Young-Jong Chung

    2014-01-01

    Full Text Available System-integrated modular advanced reactor (SMART is a small-sized advanced integral type pressurized water reactor (PWR with a rated thermal power of 330 MW. It can produce 100 MW of electricity or 90 MW of electricity and 40,000 ton of desalinated water concurrently, which is sufficient for 100,000 residents. The design features contributing to safety enhancement are basically inherent safety improvement and passive safety features. TASS/SMR code was developed for an analysis of design based events and accidents in an integral type reactor reflecting the characteristics of the SMART design. The main purpose of the code is to analyze all relevant phenomena and processes. The code should be validated using experimental data in order to confirm prediction capability. TASS/SMR predicts well the overall thermal-hydraulic behavior under various natural circulation conditions at the experimental test facility for an integral reactor. A pressure loss should be provided a function of Reynolds number at low velocity conditions in order to simulate the mass flow rate well under natural circulations.

  14. Investigation of some locally water-soluble natural polymers as circulation loss control agents during oil fields drilling

    Directory of Open Access Journals (Sweden)

    A.M. Alsabagh

    2014-03-01

    Full Text Available Eliminating or controlling lost circulation during drilling process is costly and time-consuming. Polymers play an important role in mud loss control for their viscosity due to their high molecular weight. In this paper, three natural cellulosic polymers (carboxymethyl cellulose, guar gum and potato starch were investigated as lost circulation control material by measuring different filtration parameters such as; spurt loss, fluid loss and permeability plugging tester value according to the American Petroleum Institute (API standard. The experiments were conducted in a permeability plugging apparatus (PPA at a differential pressure of 100 and 300 psi, using 10, 60 and 90 ceramic discs. From the obtained data, it was found that the 0.1% from the carboxymethyl cellulose exhibited the best results in the filtration parameters among 0.3% guar gum and 0.6% potato starch. At the same time the carboxymethyl cellulose (CMC enhanced the rheological properties of the drilling mud better than the two other used natural polymers in the term of gel strength, thixotropy, plastic and apparent viscosity. These results were discussed in the light of the adsorption and micellar formation.

  15. Study on model of onset of nucleate boiling in natural circulation with subcooled boiling using unascertained mathematics

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Tao [Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China)]. E-mail: zhoutao@mail.tsinghua.edu.cn; Wang Zenghui [Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China); Yang Ruichang [Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China)

    2005-10-01

    Experiment data got from onset of nucleate boiling (ONB) in natural circulation is analyzed using unascertained mathematics. Unitary mathematics model of the relation between the temperature and onset of nucleate boiling is built up to analysis ONB. Multiple unascertained mathematics models are also built up with the onset of natural circulation boiling equation based on the experiment. Unascertained mathematics makes that affirmative results are a range of numbers that reflect the fluctuation of experiment data more truly. The fluctuating value with the distribution function F(x) is the feature of unascertained mathematics model and can express fluctuating experimental data. Real status can be actually described through using unascertained mathematics. Thus, for calculation of ONB point, the description of unascertained mathematics model is more precise than common mathematics model. Based on the unascertained mathematics, a new ONB model is developed, which is important for advanced reactor safety analysis. It is conceivable that the unascertained mathematics could be applied to many other two-phase measurements as well.

  16. TMSR硝酸盐自然循环回路控制系统设计%Design of nitrate natural circulation loop control system in TMSR

    Institute of Scientific and Technical Information of China (English)

    张宁; 郭冰; 韩立欣; 周大勇

    2015-01-01

    Background: Nitrate natural circulation loop (NNCL) is one of experimental platform in thorium-based molten salt reactor (TMSR), which was designed to study the heat transfer behavior and corrosion behavior of direct reactor auxiliary cooling system (DRACS).Purpose: This study aims to implement a distributed control system (DCS) with functionalities of system control, online state monitor and experimental data acquisition in NNCL. Methods: An experimental physics and industrial control system (EPICS) based distributed control system was designed for this project. An optimized support module structure was designed for I/O operation with low-level PLCs to improve the performance of input/output controller (IOC) runtime database, and a PostgreSQL database was employed for data archive by RDB ChannelArchiver. A control system studio (CSS) interface and MATLAB was implemented in operator interface (OPI) computers, for visual operation and experimental data calculation.Results: Testing for online operation and history data acquisition in OPI interface proved that the control system satisfied all requirements of NNCL control and state monitor with long-term effective.Conclusion: The system could provide efficient and reliable routine for online operation and would well support advanced study of DRACS on this NNCL platform.%为了对硝酸盐自然循环回路(Nitrate Natural Circulation Loop, NNCL)的各子系统及设备的运行状态进行在线监测及远程控制,设计并实现了具有分布式结构的控制系统,并根据工程实际对其软件模块进行了改进。主要包括对过程控制软件包进行结构优化,以提高多通道模式下数据传输效率;使用PostgreSQL关系型数据库取代本地数据存储方式进行数据存档管理和和查询;在操作员计算机中更新人机界面软件以获得更好的界面效果,配置MATLAB在线驱动接口用于数据在线处理。经过运行测试表明,此系统可长期有

  17. Methods for continuous direct carbon fuel cell operation with a circulating electrolyte slurry

    Energy Technology Data Exchange (ETDEWEB)

    Harjes, Daniel I.; Dineen, Jr., D. Andrew; Guo, Liang; Calo, Joseph M.; Bloomfield, Valerie J.

    2017-02-07

    The present invention relates to methods and systems related to fuel cells, and in particular, to direct carbon fuel cells. The methods and systems relate to cleaning and removal of components utilized and produced during operation of the fuel cell, regeneration of components utilized during operation of the fuel cell, and generating power using the fuel cell.

  18. Methods for continuous direct carbon fuel cell operation with a circulating electrolyte slurry

    Science.gov (United States)

    Harjes, Daniel I.; Dineen, Jr., D. Andrew; Guo, Liang; Calo, Joseph M.; Bloomfield, Valerie J.

    2017-02-07

    The present invention relates to methods and systems related to fuel cells, and in particular, to direct carbon fuel cells. The methods and systems relate to cleaning and removal of components utilized and produced during operation of the fuel cell, regeneration of components utilized during operation of the fuel cell, and generating power using the fuel cell.

  19. Self-organizing maps applied to two-phase flow on natural circulation loop study; Aplicacao de mapas auto-organizaveis na classificacao de padroes de escoamento bifasico

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Leonardo Ferreira

    2016-11-01

    Two-phase flow of liquid and gas is found in many closed circuits using natural circulation for cooling purposes. Natural circulation phenomenon is important on recent nuclear power plant projects for decay heat removal. The Natural Circulation Facility (Circuito de Circulacao Natural CCN) installed at Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN, is an experimental circuit designed to provide thermal hydraulic data related to single and two-phase flow under natural circulation conditions. This periodic flow oscillation behavior can be observed thoroughly in this facility due its glass-made tubes transparency. The heat transfer estimation has been improved based on models that require precise prediction of pattern transitions of flow. This work presents experiments realized at CCN to visualize natural circulation cycles in order to classify two-phase flow patterns associated with phase transients and static instabilities of flow. Images are compared and clustered using Kohonen Self-organizing Maps (SOM's) applied on different digital image features. The Full Frame Discret Cosine Transform (FFDCT) coefficients were used as input for the classification task, enabling good results. FFDCT prototypes obtained can be associated to each flow pattern, enabling a better comprehension of each observed instability. A systematic test methodology was used to verify classifier robustness.

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

    Directory of Open Access Journals (Sweden)

    Juan D Rodas

    2009-07-01

    Full Text Available Rhesus macaques infected with the WE strain of lymphocytic choriomeningitis virus (LCMV-WE serve as a model for human infection with Lassa fever virus. To identify the earliest events of acute infection, rhesus macaques were monitored immediately after lethal infection for changes in peripheral blood mononuclear cells (PBMCs. Changes in CD3, CD4, CD8 and CD20 subsets did not vary outside the normal fluctuations of these blood cell populations; however, natural killer (NK and γδ T cells increased slightly on day 1 and then decreased significantly after two days. The NK subsets responsible for the decrease were primarily CD3-CD8+ or CD3-CD16+ and not the NKT (primarily CD3+CD56+ subset. Macaques infected with a non-virulent arenavirus, LCMV-Armstrong, showed a similar drop in circulating NK and γδ T cells, indicating that this is not a pathogenic event. V³9 T cells, representing the majority of circulating γδ T cells in rhesus macaques, displayed significant apoptosis when incubated with LCMV in cell culture; however, the low amount of cell death for virus-co-cultured NK cells was insufficient to account for the observed disappearance of this subset. Our observations in primates are similar to those seen in LCMV-infected mice, where decreased circulating NK cells were attributed to margination and cell death. Thus, the disappearance of these cells during acute hemorrhagic fever in rhesus macaques may be a cytokine-induced lymphopenia common to many virus infections.

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

    Science.gov (United States)

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

    2015-10-01

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

  2. Global Environmental Micro Sensors Test Operations in the Natural Environment

    Science.gov (United States)

    Adams, Mark L.; Buza, Matthew; Manobianco, John; Merceret, Francis J.

    2007-01-01

    ENSCO, Inc. is developing an innovative atmospheric observing system known as Global Environmental Micro Sensors (GEMS). The GEMS concept features an integrated system of miniaturized in situ, airborne probes measuring temperature, relative humidity, pressure, and vector wind velocity. In order for the probes to remain airborne for long periods of time, their design is based on a helium-filled super-pressure balloon. The GEMS probes are neutrally buoyant and carried passively by the wind at predetermined levels. Each probe contains onboard satellite communication, power generation, processing, and geolocation capabilities. ENSCO has partnered with the National Aeronautics and Space Administration's Kennedy Space Center (KSC) for a project called GEMS Test Operations in the Natural Environment (GEMSTONE) that will culminate with limited prototype flights of the system in spring 2007. By leveraging current advances in micro and nanotechnology, the probe mass, size, cost, and complexity can be reduced substantially so that large numbers of probes could be deployed routinely to support ground, launch, and landing operations at KSC and other locations. A full-scale system will improve the data density for the local initialization of high-resolution numerical weather prediction systems by at least an order of magnitude and provide a significantly expanded in situ data base to evaluate launch commit criteria and flight rules. When applied to launch or landing sites, this capability will reduce both weather hazards and weather-related scrubs, thus enhancing both safety and cost-avoidance for vehicles processed by the Shuttle, Launch Services Program, and Constellation Directorates. The GEMSTONE project will conclude with a field experiment in which 10 to 15 probes are released over KSC in east central Florida. The probes will be neutrally buoyant at different altitudes from 500 to 3000 meters and will report their position, speed, heading, temperature, humidity, and

  3. Testing and Implementation of the Navy's Operational Circulation Model for the Mediterranean Sea

    Science.gov (United States)

    Farrar, P. D.; Mask, A. C.

    2012-04-01

    The US Naval Oceanographic Office (NAVOCEANO) has the responsibility for running ocean models in support of Navy operations. NAVOCEANO delivers Navy-relevant global, regional, and coastal ocean forecast products on a 24 hour/7 day a week schedule. In 2011, NAVOCEANO implemented an operational version of the RNCOM (Regional Navy Coastal Ocean Model) for the Mediterranean Sea (MedSea), replacing an older variation of the Princeton Ocean Model originally set up for this area back in the mid-1990's. RNCOM is a gridded model that assimilates both satellite data and in situ profile data in near real time. This 3km MedSea RNCOM is nested within a lower resolution global NCOM in the Atlantic at the 12.5 degree West longitude. Before being accepted as a source of operational products, a Navy ocean model must pass a series of validation tests and then once in service, its skill is monitored by software and regional specialists. This presentation will provide a brief summary of the initial evaluation results. Because of the oceanographic peculiarities of this basin, the MedSea implementation posed a set of new problems for an RNCOM operation. One problem was the present Navy satellite altimetry model assimilation techniques do not improve Mediterranean NCOM forecasts, so it has been turned off, pending improvements. Another problem was that since most in-situ observations were profiling floats with short five-day profiling intervals, there was a problem with temporal aliasing when comparing these observations to the NCOM predictions. Because of the time and spatial correlations in the MedSea and in the model, the observation/model comparisons would give an unrealistically optimistic estimate of model accuracy of the Mediterranean's temperature/salinity structure. Careful pre-selection of profiles for comparison during the evaluation stage, based on spatial distribution and novelty, was used to minimize this effect. NAVOCEANO's operational customers are interested primarily in

  4. Thermal—hydraulic stability of a natural circulation system with nuclear feedback

    Institute of Scientific and Technical Information of China (English)

    XuZhan-Jie; ChenLi-Qiang; 等

    1997-01-01

    The stability of low temperature nuclear heating reactor with varous subcoolings of reacotr core inlet has been studied by means of simulating experiments.The thermalhydraulic system and the data acquisition and processing system are presented.Especially,the process of realizing the simulating nuclear feedback is introduced in detail>finally,the experimental results are discussed in the opinions of nuclear reactor physics and thermal-hydraulics,The conclusion is that the nuclear reactor can operate stably only when the subcoopling of reactor core inlet is high enough.

  5. Fluid circulating pump operated by same incident solar energy which heats energy collection fluid

    Science.gov (United States)

    Collins, E. R.

    1980-01-01

    The application of using a spacecraft solar powered pump terrestrially to reduce or eliminate the need for fossil fuel generated electricity for domestic solar hot water systems was investigated. A breadboard prototype model was constructed utilizing bimetals to convert thermal energy into mechanical motion by means of a toggle operated shutter mechanism. Although it did not meet expected thermal efficiency, the prototype model was sufficient to demonstrate the mechanical concept.

  6. Tank 241-AZ-101 and Tank 241-AZ-102 Airlift Circulator Operation Vapor Sampling and Analysis Plan

    Energy Technology Data Exchange (ETDEWEB)

    TEMPLETON, A.M.

    1999-12-07

    This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained during the operation of the tank 241-AZ-101 and 241-AZ-102 airlift circulators (ALCs) and during the initial operation (''bump'') of the tank 241-AZ-101 mixer pumps. The purpose of the ALC operation is to support portions of the operational test procedure (OTP) for Project W-030 (OTP-W030-001) and to perform functional test in support of Project W-151. Project W-030 is the 241-A-702 ventilation upgrade project (241-142-702) and Project W-151 is the 241-AZ-101 Mixer Pump Test. The functional tests will check the operability of the tank 241-AZ-101 ALCs. Process Memo's No. 2E98-082 and No. 2E99-001 (LMHC 1999a, LMHC 1999b) direct the operation of the ALCs and the Industrial Hygiene monitoring respectively. A series of tests will be conducted in which the ALCs in tanks 241-AZ-101 and 241-AZ-102 will be operated at different air flow rates. Vapor samples will be obtained to determine constituents that may be present in the tank headspace during ALC operation at tanks 241-AZ-101 and 241-AZ-102 as the waste is disturbed. During the testing, vapor samples will be obtained from the headspace of tanks 241-AZ-101 and 241-AZ-102 via the unused port on the standard hydrogen monitoring system (SHMS). In addition the last two vapor samples will be collected from the headspace of tank 241-AZ-101 during the operation of the mixer pumps. Each mixer pump will be operated for approximately 5 minutes. Results will be used to provide the waste feed delivery program with environmental air permitting data for tank waste disturbing activities. Because of radiological concerns, the samples will be filtered for particulates. It is recognized that this may remove some organic compounds. The following sections provide the general methodology and procedures to be used in the

  7. The complex of looped diagrams and natural operations on Hochschild homology

    DEFF Research Database (Denmark)

    Klamt, Angela

    In this thesis natural operations on the (higher) Hochschild complex of a given family of algebras are investigated. We give a description of all formal operations (in the sense of Wahl) for the class of commutative algebras using Loday's lambda operation, Connes' boundary operator and shue produ...... of formal operations on Hochschild homology to higher Hochschild homology. We also generalize statements about the formal operations and give smaller models for the formal operations on higher Hochschild homology in certain cases....

  8. HIV Type 1 Integrase Natural Polymorphisms in Viral Variants Circulating in FSU Countries.

    Science.gov (United States)

    Lapovok, Ilya; Laga, Vita; Kazennova, Elena; Bobkova, Marina

    2017-08-15

    Natural variability of integrase (IN) across HIV-1 variants may influence the emergence of resistant viruses. The most apparent explanation of these fact is the IN polymorphism and the associated differences in codon usage, which, in turn, influence the probability and the terms of DRMs acquisition. Possible mechanisms by which polymorphisms affect DRMs emergence remain disputed and should still be clarified because these substitutions may be associated with a reduced activity of some INSTIs and may impact on ART regimen choice depending of HIV-1 subtype. The aim of this work was to assess the prevalence of naturally occurring polymorphisms within the HIV-1 integrase gene, which might influence the susceptibility to INSTIs, among the patients from Russia and former USSR countries, according to HIV-1 subtypes. A study involved 506 HIV-1 IN sequences of INSTI-naive patients from Russia, Ukraine, Armenia, Kyrgyzstan, Kazakhstan, Uzbekistan, Belarus, and Georgia. Among them, 194 sequences were newly obtained in this study and 312 were downloaded from Los-Alamos database. The proviral DNA was sequenced using an in-house PCR protocol designed on the basis of a well-conserved integrase region in order to detect all HIV-1 variants. The phylogenetic analyses based on IN population sequencing found subtype A6 being the most prevalent (259) (51.2%) in the collection studied, followed by subtype G (36) (7.1%), AG-recombinants (148) (29.3%), subtype B (50) (9.9%), and CRF03_AB (5) (1,0%). The major INSTI resistance-associated mutations (DRMs) were found only in two A6 samples. The prevalence of minor/accessory substitutions depended on HIV-1 variants, while the most notable findings were L74I in subtype A6 (93.1%) and E157Q in subtype B (44.0%). Most of minor DRMs and polymorphic substitutions were concentrated in the central catalytic domain of the IN molecule. Both the DDE triad and HHCC zinc binding motifs were fully conserved. The results of the study suggest a very low

  9. [Operative neurosurgery: personal view and historical backgrounds (3). Anterior circulation--pterional approach].

    Science.gov (United States)

    Yonekawa, Yasuhiro

    2007-07-01

    Under the title of anterior circulation aneurysms and the pterional approach, followings are presented and emphasized along with mentioning their historical development in our present performance status. Pterional approach: head positioning with Mayfield-Kees fixation apparatus using one pin around the processus matoideus and the other 2 pins on the contralateral side behind the hair line the head turned 30 degrees and reclined chin-up l5-20 grade. Skin incision beginning just in front of the tragus ending up at the midline hair line in a curvilinear fashion always including the superficial temporal artery STA in its frontal branch and the facial nerve (frontal branch) in the skin flap. A muscle fascial preparation is so fashioned such that a strip of myofascial cuff is left at the linea temporalis and the temporal musculature is reflected and retracted towards the postero-basal direction in order to expose the pterion, for which a small short myofascial incision is added parallel to the skin incision towards the tragus up to several cm above it to prevent postoperative trismus. Bone flap is sawed out usually using three burr holes, at the key hole just at the proximal part of the linea temporalis, frontomedially on the squama frontalis and on the sutura squamosa, so that the Sylvian fissure and the superior temporal gyrus are exposed enough for further procedure. The sphenoid ridge is drilled away until the most lateral corner of the superior orbital fissure comes into view. Thus one has drilled away enough to do surgery in question at the skull base even at the time of "angry brain" due to subarachnoid hemorrhage SAH. This procedure can be followed by selective extradural anterior clinoidectomy SEAC in case of necessity. The dura is opened in a curvilinear fashion so that the dura can be reflected over the drilled sphenoid wing and so that the Sylvian fissure and the superior temporal gyrus is exposed for the treatment of aneurysms of the internal carotid artery

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

    Energy Technology Data Exchange (ETDEWEB)

    Moisseytsev, A.; Sienicki, J. J.

    2007-03-08

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

  11. Store-operated channels in the pulmonary circulation of high- and low-altitude neonatal lambs.

    Science.gov (United States)

    Parrau, Daniela; Ebensperger, Germán; Herrera, Emilio A; Moraga, Fernando; Riquelme, Raquel A; Ulloa, César E; Rojas, Rodrigo T; Silva, Pablo; Hernandez, Ismael; Ferrada, Javiera; Diaz, Marcela; Parer, Julian T; Cabello, Gertrudis; Llanos, Aníbal J; Reyes, Roberto V

    2013-04-15

    We determined whether store-operated channels (SOC) are involved in neonatal pulmonary artery function under conditions of acute and chronic hypoxia, using newborn sheep gestated and born either at high altitude (HA, 3,600 m) or low altitude (LA, 520 m). Cardiopulmonary variables were recorded in vivo, with and without SOC blockade by 2-aminoethyldiphenylborinate (2-APB), during basal or acute hypoxic conditions. 2-APB did not have effects on basal mean pulmonary arterial pressure (mPAP), cardiac output, systemic arterial blood pressure, or systemic vascular resistance in both groups of neonates. During acute hypoxia 2-APB reduced mPAP and pulmonary vascular resistance in LA and HA, but this reduction was greater in HA. In addition, isolated pulmonary arteries mounted in a wire myograph were assessed for vascular reactivity. HA arteries showed a greater relaxation and sensitivity to SOC blockers than LA arteries. The pulmonary expression of two SOC-forming subunits, TRPC4 and STIM1, was upregulated in HA. Taken together, our results show that SOC contribute to hypoxic pulmonary vasoconstriction in newborn sheep and that SOC are upregulated by chronic hypoxia. Therefore, SOC may contribute to the development of neonatal pulmonary hypertension. We propose SOC channels could be potential targets to treat neonatal pulmonary hypertension.

  12. Overview of the system alone and system/CFD coupled calculations of the PHENIX Natural Circulation Test within the THINS project

    Energy Technology Data Exchange (ETDEWEB)

    Pialla, David, E-mail: david.pialla@cea.fr [Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), DEN/DM2S/STMF, 17 rue des martyrs, 38054 Grenoble Cedex 9 (France); Tenchine, Denis [Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), DEN/DM2S/STMF, 17 rue des martyrs, 38054 Grenoble Cedex 9 (France); Li, Simon [Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), DEN/DM2S/STMF, 91191 Gif-sur-Yvette Cedex (France); Gauthe, Paul; Vasile, Alfredo [Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), DEN/DER/SESI, 13108 Saint Paul Lez Durance Cedex (France); Baviere, Roland; Tauveron, Nicolas; Perdu, Fabien [Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), DEN/DM2S/STMF, 17 rue des martyrs, 38054 Grenoble Cedex 9 (France); Maas, Ludovic; Cocheme, François [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN/SEMIA/BAST, B.P. 17, 92262 Fontenay-aux-Roses Cedex (France); Huber, Klaus; Cheng, Xu [Karlsruhe Institute of Technology (KIT), Institute of Fusion and Reactor Technology (IFRT), Kaiserstraße 12, Building 07.08, 76131 Karlsruhe (Germany)

    2015-08-15

    Highlights: • The PHENIX natural convection test performed during the end of life tests program. • The calculation with system codes and theirs limits. • The calculation with coupling CFD and system code, which allows better prediction. • The tasks of code validation have been done in the frame of the THINS project. - Abstract: The PHENIX sodium cooled fast reactor started operation in 1973 and was shut down in 2009. Before decommissioning, an ultimate test program was designed and performed to provide valuable data for the development of future sodium cooled fast reactors, as the so-called Astrid prototype in France. Among these ultimate tests, a thermal-hydraulic Natural Convection Test (NCT) was set-up in June 2009. Starting from a reduced power state of 120 MWt, the NCT consists of a loss of the heat sink combined with a reactor scram and a primary pumps trip leading to stabilized natural circulation in the primary sodium system. The thermal-hydraulics innovative system project (THINS project), sponsored by the European Community in the frame of the 7th FP has selected this transient for validation of both stand-alone system code simulations and coupled simulations using system and CFD codes. Participants from three organizations (CEA, IRSN and KIT) have addressed this transient using different system codes (CATHARE, DYN2B and ATHLET) and CFD codes (TRIO-U and OPEN FOAM). The present paper depicts the different modeling approaches, methodologies and compares the numerical results with the available experimental data. Finally, the main lessons learned from the work performed within the THINS project on the PHENIX NCT with respect to code development and validation are summarized.

  13. Experiments for heat transfer characteristics and natural circulation performance of PRHRS of the high temperature/high pressure thermal-hydraulic test facility(VISTA)

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyun Sik; Choi, Ki Yong; Cho, Seok; Lee, Sung Jae; Song, Chul Hwa; Park, Chun Kyong; Chung, Moon Ki

    2004-01-01

    The VISTA (Experimental Verification by Integral Simulation of Transients and Accidents) is an experimental facility to verify the performance and safety issues of the SMART-P (Pilot plant of the System-integrated Modular Advanced Reactor). The basic design of the SMART-P has been completed by KAERI. The present report describes the experimental results on the heat transfer characteristics and the natural circulation performance of the PRHRS of the VISTA facility. A stable flow occurs in a natural circulation loop which is composed of a steam generator secondary side, a secondary system, and a PRHRS, and its flow rate corresponds to 12% of the rated feedwater flowrate of the secondary system. The heat transfers through the PRHRS heat exchanger and the emergency cooldown tank are sufficient enough to enable stable natural circulation. In the primary loop the natural circulation occurs due to the core decay heat and the heat removal of the steam generator. Although the flow rate in the primary loop fluctuates a little, the decay heat is removed easily.

  14. Internal combustion engine for natural gas compressor operation

    Energy Technology Data Exchange (ETDEWEB)

    Hagen, Christopher; Babbitt, Guy

    2016-12-27

    This application concerns systems and methods for compressing natural gas with an internal combustion engine. In a representative embodiment, a method is featured which includes placing a first cylinder of an internal combustion engine in a compressor mode, and compressing a gas within the first cylinder, using the cylinder as a reciprocating compressor. In some embodiments a compression check valve system is used to regulate pressure and flow within cylinders of the engine during a compression process.

  15. A Computing Approach with the Heat-Loss Model for the Transient Analysis of Liquid Metal Natural Circulation Loop

    Directory of Open Access Journals (Sweden)

    Daogang Lu

    2014-01-01

    Full Text Available The transient behaviors of natural circulation loop (NCL are important for the system reliability under postulated accidents. The heat loss and structure thermal inertia may influence the transient behaviors of NCL greatly, so a transient analysis model with consideration of heat loss was developed based on the MATLAB/Simulink to predict the thermal-hydraulic characteristic of liquid metal NCL. The transient processes including the start-up, the loss of pump, and the shutdown of thermal-hydraulic ADS lead bismuth loop (TALL experimental facility were simulated by using the model. A good agreement is obtained to validate the transient model. The appended structure would provide significant thermal inertia and flatten the temperature distribution in the transients. The oscillations of temperature and flow rate are also weakened. The temperature difference between hot leg and cold leg would increase with the decrease of heat loss, so the flow rate increases as well. However, a significant increase of hot section temperature may cause a failure of facility integrity due to the decrease of heat loss. Hence, the full power of the core tank may also be limited.

  16. Malthus and the Philanthropists, 1764–1859: The Cultural Circulation of Political Economy, Botany, and Natural Knowledge

    Directory of Open Access Journals (Sweden)

    J. Marc MacDonald

    2017-01-01

    Full Text Available Modernity does not possess a monopoly on mass incarceration, population fears, forced migration, famine, or climatic change. Indeed, contemporary and early modern concerns over these matters have extended interests in Thomas Malthus. Yet, despite extensive research on population issues, little work explicates the genesis of population knowledge production or how the process of intellectual transfer occurred during the eighteenth and early nineteenth centuries. This paper examines the Delessert network’s instrumental role in cultivating, curating, and circulating knowledge that popularized Malthusian population theory, including the theory’s constitutive elements of political economy, philanthropy, industry, agriculture, and botany. I show how deviant, nonconformist groups suffered forced migration for their political philosophy, particularly during the revolutionary 1790s, resulting in their imprisonment and migration to America. A consequence of these social shifts was the diffusion and dissemination of population theory—as a pursuit of scientific knowledge and exploration—across both sides of the Atlantic. By focusing on the Delesserts and their social network, I find that a byproduct of inter and intra continental migration among European elites was a knowledge exchange that stimulated Malthus’s thesis on population and Genevan Augustin Pyramus Candolle’s research on botany, ultimately culminating in Charles Darwin’s theory of natural selection and human evolution.

  17. Evaluation of some natural water-insoluble cellulosic material as lost circulation control additives in water-based drilling fluid

    Directory of Open Access Journals (Sweden)

    Ahmed Mohamed Alsabagh

    2015-12-01

    In this work, three natural water-insoluble cellulosic materials; peanut hulls, bagasse and sawdust were investigated as lost circulation control materials. One hundred and eight different LCM samples made of various materials were tested with mud. The experiments were conducted in a permeability plugging apparatus (PPA at a differential pressure of 100 psi and 300 psi, using 10, 60 and 90 ceramic discs. The performance of each LCM sample was determined based on the amount of spurt loss and total fluid loss of the mud according to the American Petroleum Institute (API standard. The obtained results showed that, the amount of the fluid loss depends on the LCM material, concentration and size distribution, testing results show that, the peanut gives the best results among the bagasse and sawdust, especially fine size which exhibited better results in the filtration characteristics due to the better filling properties of this size. Peanut hulls, bagasse and sawdust show a slight effect on the rheological properties of the mud. The results were discussed on light of particle size distribution.

  18. Operational Decisions: What is the Nature of the Information Required?

    Science.gov (United States)

    1987-05-21

    ground and a decisive battle would be fought between the Chindwin and Irrawaddy River with the city of Mandalay in the balance, Slim was In error, He...with elements of the IV Corps and continue the advance toward the Irrawaddy River giving every 1r,-.,.:.’tion that Mandalay was the objective of the 14th...Corps would cross the Irrawaddy and seize Mandalay without the threat of the Japanese defense being reinforced. A subsequent phase of the operation was

  19. Abundance and Utility: For Military Operations, Liquid Fuels Remain a Solid Choice over Natural Gas

    Science.gov (United States)

    2014-08-01

    and combat support vehicles, ships, and aircraft, the adoption of natural gas —whether as compressed natural gas (CNG) or liquefied natural gas (LNG...tacticaldefensemedia.com16 | DoD Power & Energy Fall 2014 For Military Operations, Liquid Fuels Remain a Solid Choice over Natural Gas By Bret...Strogen and Patrick Lobner Abundance and Utility Fueling the Force Natural Gas M ilitary energy strategists often recount the British Royal Navy’s decision

  20. Coordinated Operation of the Electricity and Natural Gas Systems with Bi-directional Energy Conversion

    DEFF Research Database (Denmark)

    Zeng, Qing; Zhang, Baohua; Fang, Jiakun

    2017-01-01

    A coordinated operation of the natural gas and electricity network with bi-directional energy conversion is expected to accommodate high penetration levels of renewables. This work focuses on the unified optimal operation of the integrated natural gas and electricity system considering the network...

  1. Relationship between composition of mixture charged and that in circulation in an auto refrigerant cascade and a J-T refrigerator operating in liquid refrigerant supply mode

    Science.gov (United States)

    Sreenivas, Bura; Nayak, H. Gurudath; Venkatarathnam, G.

    2017-01-01

    The composition of the refrigerant mixture in circulation during steady state operation of J-T and allied refrigerators is not the same as that charged due to liquid hold up in the heat exchangers and phase separators, as well as the differential solubility of different refrigerant components in the compressor lubricating oil. The performance of refrigerators/liquefiers operating on mixed refrigerant cycles is dependent on the mixture composition. It is therefore important to charge the right mixture that results in an optimum composition in circulation during steady state operation. The relationship between the charged and circulating composition has been experimentally studied in a J-T refrigerator operating in the liquid refrigerant supply (LRS) mode and an auto refrigerant cascade refrigerator (with a phase separator) operating in the gas refrigerant supply (GRS) mode. The results of the study are presented in this work. The results show that the method presented earlier for J-T refrigerators operating in GRS mode is also applicable in the case of refrigerators studied in this work.

  2. Blade-to-coolant heat-transfer results and operating data from a natural-convection water-cooled single-stage turbine

    Science.gov (United States)

    Diaguila, Anthony J; Freche, John C

    1951-01-01

    Blade-to-coolant heat-transfer data and operating data were obtained with a natural-convection water-cooled turbine over range of turbine speeds and inlet-gas temperatures. The convective coefficients were correlated by the general relation for natural-convection heat transfer. The turbine data were displaced from a theoretical equation for natural convection heat transfer in the turbulent region and from natural-convection data obtained with vertical cylinders and plates; possible disruption of natural convection circulation within the blade coolant passages was thus indicated. Comparison of non dimensional temperature-ratio parameters for the blade leading edge, midchord, and trailing edge indicated that the blade cooling effectiveness is greatest at the midchord and least at the trailing edge.

  3. Internal combustion engine for natural gas compressor operation

    Energy Technology Data Exchange (ETDEWEB)

    Hagen, Christopher L.; Babbitt, Guy; Turner, Christopher; Echter, Nick; Weyer-Geigel, Kristina

    2016-04-19

    This application concerns systems and methods for compressing natural gas with an internal combustion engine. In a representative embodiment, a system for compressing a gas comprises a reciprocating internal combustion engine including at least one piston-cylinder assembly comprising a piston configured to travel in a cylinder and to compress gas in the cylinder in multiple compression stages. The system can further comprise a first pressure tank in fluid communication with the piston-cylinder assembly to receive compressed gas from the piston-cylinder assembly until the first pressure tank reaches a predetermined pressure, and a second pressure tank in fluid communication with the piston-cylinder assembly and the first pressure tank. The second pressure tank can be configured to receive compressed gas from the piston-cylinder assembly until the second pressure tank reaches a predetermined pressure. When the first and second pressure tanks have reached the predetermined pressures, the first pressure tank can be configured to supply gas to the piston-cylinder assembly, and the piston can be configured to compress the gas supplied by the first pressure tank such that the compressed gas flows into the second pressure tank.

  4. Perinatal outcomes and unconventional natural gas operations in Southwest Pennsylvania.

    Directory of Open Access Journals (Sweden)

    Shaina L Stacy

    Full Text Available Unconventional gas drilling (UGD has enabled extraordinarily rapid growth in the extraction of natural gas. Despite frequently expressed public concern, human health studies have not kept pace. We investigated the association of proximity to UGD in the Marcellus Shale formation and perinatal outcomes in a retrospective cohort study of 15,451 live births in Southwest Pennsylvania from 2007-2010. Mothers were categorized into exposure quartiles based on inverse distance weighted (IDW well count; least exposed mothers (first quartile had an IDW well count less than 0.87 wells per mile, while the most exposed (fourth quartile had 6.00 wells or greater per mile. Multivariate linear (birth weight or logistical (small for gestational age (SGA and prematurity regression analyses, accounting for differences in maternal and child risk factors, were performed. There was no significant association of proximity and density of UGD with prematurity. Comparison of the most to least exposed, however, revealed lower birth weight (3323 ± 558 vs 3344 ± 544 g and a higher incidence of SGA (6.5 vs 4.8%, respectively; odds ratio: 1.34; 95% confidence interval: 1.10-1.63. While the clinical significance of the differences in birth weight among the exposure groups is unclear, the present findings further emphasize the need for larger studies, in regio-specific fashion, with more precise characterization of exposure over an extended period of time to evaluate the potential public health significance of UGD.

  5. Perinatal outcomes and unconventional natural gas operations in Southwest Pennsylvania.

    Science.gov (United States)

    Stacy, Shaina L; Brink, LuAnn L; Larkin, Jacob C; Sadovsky, Yoel; Goldstein, Bernard D; Pitt, Bruce R; Talbott, Evelyn O

    2015-01-01

    Unconventional gas drilling (UGD) has enabled extraordinarily rapid growth in the extraction of natural gas. Despite frequently expressed public concern, human health studies have not kept pace. We investigated the association of proximity to UGD in the Marcellus Shale formation and perinatal outcomes in a retrospective cohort study of 15,451 live births in Southwest Pennsylvania from 2007-2010. Mothers were categorized into exposure quartiles based on inverse distance weighted (IDW) well count; least exposed mothers (first quartile) had an IDW well count less than 0.87 wells per mile, while the most exposed (fourth quartile) had 6.00 wells or greater per mile. Multivariate linear (birth weight) or logistical (small for gestational age (SGA) and prematurity) regression analyses, accounting for differences in maternal and child risk factors, were performed. There was no significant association of proximity and density of UGD with prematurity. Comparison of the most to least exposed, however, revealed lower birth weight (3323 ± 558 vs 3344 ± 544 g) and a higher incidence of SGA (6.5 vs 4.8%, respectively; odds ratio: 1.34; 95% confidence interval: 1.10-1.63). While the clinical significance of the differences in birth weight among the exposure groups is unclear, the present findings further emphasize the need for larger studies, in regio-specific fashion, with more precise characterization of exposure over an extended period of time to evaluate the potential public health significance of UGD.

  6. Internal combustion engine for natural gas compressor operation

    Science.gov (United States)

    Hagen, Christopher L.; Babbitt, Guy; Turner, Christopher; Echter, Nick; Weyer-Geigel, Kristina

    2016-04-19

    This application concerns systems and methods for compressing natural gas with an internal combustion engine. In a representative embodiment, a system for compressing a gas comprises a reciprocating internal combustion engine including at least one piston-cylinder assembly comprising a piston configured to travel in a cylinder and to compress gas in the cylinder in multiple compression stages. The system can further comprise a first pressure tank in fluid communication with the piston-cylinder assembly to receive compressed gas from the piston-cylinder assembly until the first pressure tank reaches a predetermined pressure, and a second pressure tank in fluid communication with the piston-cylinder assembly and the first pressure tank. The second pressure tank can be configured to receive compressed gas from the piston-cylinder assembly until the second pressure tank reaches a predetermined pressure. When the first and second pressure tanks have reached the predetermined pressures, the first pressure tank can be configured to supply gas to the piston-cylinder assembly, and the piston can be configured to compress the gas supplied by the first pressure tank such that the compressed gas flows into the second pressure tank.

  7. Scaled Facility Design Approach for Pool-Type Lead-Bismuth Eutectic Cooled Small Modular Reactor Utilizing Natural Circulation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sangrok; Shin, Yong-Hoon; Lee, Jueun; Hwang, Il Soon [Seoul National University, Seoul (Korea, Republic of)

    2015-10-15

    In low carbon era, nuclear energy is the most prominent energy source of electricity. For steady ecofriendly nuclear energy supply, Generation IV reactors which are future nuclear reactor require safety, sustainability, economics and non-proliferation as four criteria. Lead cooled fast reactor (LFR) is one of these reactor type and Generation IV international forum (GIF) adapted three reference LFR systems which are a small and movable systems with long life without refueling, intermediate size and huge electricity generation system for power grid. NUTRECK (Nuclear Transmutation Energy Center of Korea) has been designed reactor called URANUS (Ubiquitous, Rugged, Accident-forgiving, Non-proliferating, and Ultra-lasting Sustainer) which is small modular reactor and using lead-bismuth eutectic coolant. To prove natural circulation capability of URANUS and analyze design based accidents, scaling mock-up experiment facility will be constructed. In this paper, simple specifications of URANUS will be presented. Then based on this feature, scaling law and scaled facility design results are presented. To validate safety feature and thermodynamics characteristic of URANUS, scaled mockup facility of URANUS is designed based on the scaling law. This mockup adapts two area scale factors, core and lower parts of mock-up are scaled for 3D flow experiment. Upper parts are scaled different size to reduce electricity power and LBE tonnage. This hybrid scaling method could distort some thermal-hydraulic parameters, however, key parameters for experiment will be matched for up-scaling. Detailed design of mock-up will be determined through iteration for design optimization.

  8. Mass flow rate sensitivity and uncertainty analysis in natural circulation boiling water reactor core from Monte Carlo simulations

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa-Paredes, Gilberto, E-mail: gepe@xanum.uam.m [Area de Ingenieria en Recursos Energeticos, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco, 186, Col. Vicentina, Mexico D.F., 09340 (Mexico); Verma, Surendra P. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Priv. Xochicalco s/no., Col Centro, Apartado Postal 34, Temixco 62580 (Mexico); Vazquez-Rodriguez, Alejandro [Area de Ingenieria en Recursos Energeticos, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco, 186, Col. Vicentina, Mexico D.F., 09340 (Mexico); Nunez-Carrera, Alejandro [Comision Nacional de Seguridad Nuclear y Salvaguardias, Doctor Barragan 779, Col. Narvarte, Mexico D.F. 03020 (Mexico)

    2010-05-15

    Our aim was to evaluate the sensitivity and uncertainty of mass flow rate in the core on the performance of natural circulation boiling water reactor (NCBWR). This analysis was carried out through Monte Carlo simulations of sizes up to 40,000, and the size, i.e., repetition of 25,000 was considered as valid for routine applications. A simplified boiling water reactor (SBWR) was used as an application example of Monte Carlo method. The numerical code to simulate the SBWR performance considers a one-dimensional thermo-hydraulics model along with non-equilibrium thermodynamics and non-homogeneous flow approximation, one-dimensional fuel rod heat transfer. The neutron processes were simulated with a point reactor kinetics model with six groups of delayed neutrons. The sensitivity was evaluated in terms of 99% confidence intervals of the mean to understand the range of mean values that may represent the entire statistical population of performance variables. The regression analysis with mass flow rate as the predictor variable showed statistically valid linear correlations for both neutron flux and fuel temperature and quadratic relationship for the void fraction. No statistically valid correlation was observed for the total heat flux as a function of the mass flow rate although heat flux at individual nodes was positively correlated with this variable. These correlations are useful for the study, analysis and design of any NCBWR. The uncertainties were propagated as follows: for 10% change in the mass flow rate in the core, the responses for neutron power, total heat flux, average fuel temperature and average void fraction changed by 8.74%, 7.77%, 2.74% and 0.58%, respectively.

  9. Communicating for Climate Change Adaptation: Lessons from a Case Study with Nature-Based Tour Operators

    Science.gov (United States)

    Timm, K.; Sparrow, E. B.; Pettit, E. C.; Trainor, S. F.; Taylor, K.

    2014-12-01

    Increasing temperatures are projected to have a positive effect on the length of Alaska's tourism season, but the natural attractions that tourism relies on, such as glaciers, wildlife, fish, or other natural resources, may change. In order to continue to derive benefits from these resources, nature-based tour operators may have to adapt to these changes, and communication is an essential, but poorly understood, component of the climate change adaptation process. The goal of this study was to determine how to provide useful climate change information to nature-based tour operators by answering the following questions: 1. What environmental changes do nature-based tour operators perceive? 2. How are nature-based tour operators responding to climate and environmental change? 3. What climate change information do nature-based tour operators need? To answer these questions, twenty-four nature-based tour operators representing 20 different small and medium sized businesses in Juneau, Alaska were interviewed. The results show that many of Juneau's nature-based tour operators are observing, responding to, and in some cases, actively planning for further changes in the environment. The types of responses tended to vary depending on the participants' certainty in climate change and the perceived risks to their organization. Using these two factors, this study proposes a framework to classify climate change responses for the purpose of generating meaningful information and communication processes that promote adaptation and build adaptive capacity. During the course of the study, several other valuable lessons were learned about communicating about adaptation. The results of this study demonstrate that science communication research has an important place in the practice of promoting and fostering climate change adaptation. While the focus of this study was tour operators, the lessons learned may be valuable to other organizations striving to engage unique groups in climate

  10. Experimental study on two-phase flow natural circulation in a core catcher cooling channel for EU-APR1400 using air-water system

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ki Won [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Korea Atomic Energy Research Institute, Daejeon 34057 (Korea, Republic of); Nguyen, Thanh Hung [School of Nuclear Engineering, Purdue University, West Lafayette, IN 47906 (United States); Ha, Kwang Soon; Kim, Hwan Yeol; Song, Jinho [Korea Atomic Energy Research Institute, Daejeon 34057 (Korea, Republic of); Park, Hyun Sun [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Revankar, Shripad T., E-mail: shripad@postech.ac.kr [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); School of Nuclear Engineering, Purdue University, West Lafayette, IN 47906 (United States); Kim, Moo Hwan [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Korea Institute of Nuclear Safety, Daejeon 305-338 (Korea, Republic of)

    2017-05-15

    Highlights: • Two-phase flow regimes and transition behavior were observed in the coolant channel. • Test were conducted for natural circulation with air-water. • Data were obtained on flow regime, void fraction, flow rates and re-wetting time. • The data were related to a cooling capability of core catcher system. - Abstract: Ex-vessel core catcher cooling system driven by natural circulation is designed using a full scaled air-water system. A transparent half symmetric section of a core catcher coolant channel of a pressurized water reactor was designed with instrumentations for local void fraction measurement and flow visualization. Two designs of air-water top separator water tanks are studied including one with modified ‘super-step’ design which prevents gas entrainment into down-comer. In the experiment air flow rates are set corresponding to steam generation rate for given corium decay power. Measurements of natural circulation flow rate, spatial local void fraction distribution and re-wetting time near the top wall are carried out for various air flow rates which simulate boiling-induced vapor generation. Since heat transfer and critical heat flux are strongly dependent on the water mass flow rate and development of two-phase flow on the heated wall, knowledge of two-phase flow characteristics in the coolant channel is essential. Results on flow visualization showing two phase flow structure specifically near the high void accumulation regions, local void profiles, rewetting time, and natural circulation flow rate are presented for various air flow rates that simulate corium power levels. The data are useful in assessing the cooling capability of and safety of the core catcher system.

  11. Study on Instability of Natural Circulation Induced by Subcooled Boiling%欠热沸腾诱发自然循环不稳定性的研究

    Institute of Scientific and Technical Information of China (English)

    彭天骥; 邱金荣; 郭赟; 曾和义

    2013-01-01

    The best estimate system analysis code RELAP5 was used to analyze the natural circulation systems. The instability boundaries of one natural circulation system were obtained under different conditions. According to present results, most of the boundary points were found in the low subcooled boiling zone. The natural circulation systems can tolerate high subcooled boiling, and the disturbance of bubbles departing from the wall and condensing in the subcooled boiling region may be the inherent source to induce the instability, then the flow oscillations can become self-sustained and evolve because of the phase differences among system driving force, resistance and flow rate.%以最佳估算程序RELAP5为基本分析工具,对自然循环系统进行数值分析,得出了不同条件下系统的不稳定性边界.研究发现自然循环对过冷沸腾有一定的承受能力,不稳定性一般发生在低欠热沸腾区,气泡脱离壁面和凝结时的扰动可能是自然循环系统不稳定性的诱因,系统驱动力、阻力和流量之间的相位差使振荡得以维持和发展.

  12. Operation method of circulation blower of fuel cell power generation system; Nenryo denchi hatsuden sochi no junkan buroa unten hoho

    Energy Technology Data Exchange (ETDEWEB)

    Iida, T. [Fuji Electric Co. Ltd., Tokyo (Japan)

    1998-02-13

    The conventional circulation blower of fuel cell power generation system has such problem as generating a big pressure difference between electrodes. When the blower is started, the pressure difference is caused by sudden start of suction of cell exhaust gas from the upper stream of the circulation blower since the starting is done in total voltage start by switch. When the blower is stopped, the pressure difference is also caused by sudden stop of suction of cell exhaust gas from the upper stream of the circulation blower. In the invention, the motor driving the circulation blower which circulates the cell exhaust gas of fuel cell power generation system to the cell inlet is equipped with a rotation control system (VVVF). When the blower is started, a smooth start of blower, or smooth start of suction of exhaust gas is given by the control system because the rotation speed is gradually increased from low speed. When the blower is stopped, a smooth stop of blower, or smooth stop of suction of exhaust gas is given by the control system because the rotation speed is gradually decreased from high speed to low speed. In this way, the generation of extreme pressure difference between electrodes of fuel cell can be suppressed. 2 figs.

  13. Detailed evaluation of two phase natural circulation flow in the cooling channel of the ex-vessel core catcher for EU-APR1400

    Energy Technology Data Exchange (ETDEWEB)

    Park, Rae-Joon, E-mail: rjpark@kaeri.re.kr; Ha, Kwang-Soon; Rhee, Bo-Wook; Kim, Hwan Yeol

    2016-03-15

    Highlights: • Ex-vessel core catcher of PECS is installed in EU-APR1400. • CE-PECS has been conducted to test a cooling capability of the PECS. • Two phase flow in CE-PECS and PECS was analyzed using RELAP5/MOD3. • RELAP5 results are very similar to the CE-PECS data. • The super-step design is suitable for steam injection into the downcomer in PECS. - Abstract: The ex-vessel core catcher of the PECS (Passive Ex-vessel corium retaining and Cooling System) is installed to retain and cool down the corium in the reactor cavity of the EU (European Union)-APR (Advanced Power Reactor) 1400. A verification experiment on the cooling capability of the PECS has been conducted in the CE (Cooling Experiment)-PECS. Simulations of a two-phase natural circulation flow using the RELAP5/MOD3 computer code in the CE-PECS and PECS have been conducted to predict the two-phase flow characteristics, to determine the natural circulation mass flow rate in the cooling channel, and to evaluate the scaling in the experimental design of the CE-PECS. Particularly from a comparative study of the prototype PECS and the scaled test facility of the CE-PECS, the orifice loss coefficient in the CE-PECS was found to be 6 to maintain the coolant circulation mass flux, which is approximately 273.1 kg/m{sup 2} s. The RELAP5 results on the coolant circulation mass flow rate are very similar to the CE-PECS experimental results. An increase in the coolant injection temperature and the heat flux lead to an increase in the coolant circulation mass flow rate. In the base case simulation, a lot of vapor was injected into the downcomer, which leads to an instability of the two-phase natural circulation flow. A super-step design at a downcomer inlet is suitable to prevent vapor injection into the downcomer piping.

  14. TECHNOLOGIES TO ENHANCE OPERATION OF THE EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn

    2004-03-01

    This report documents work performed in Phase I of the project entitled: ''Technologies to Enhance Operation of the Existing Natural Gas Compression Infrastructure''. The project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity. The report describes a number of potential enhancements to the existing natural gas compression infrastructure that have been identified and qualitatively demonstrated in tests on three different integral engine/compressors in natural gas transmission service.

  15. TECHNOLOGIES TO ENHANCE OPERATION OF THE EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn

    2004-08-01

    This report documents work performed in Phase I of the project entitled: ''Technologies to Enhance Operation of the Existing Natural Gas Compression Infracture''. The project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity. The report describes a number of potential enhancements to the existing natural gas compression infrastructure that have been identified and tested on four different integral engine/compressors in natural gas transmission service.

  16. Popular epidemiology and "fracking": citizens' concerns regarding the economic, environmental, health and social impacts of unconventional natural gas drilling operations.

    Science.gov (United States)

    Powers, Martha; Saberi, Poune; Pepino, Richard; Strupp, Emily; Bugos, Eva; Cannuscio, Carolyn C

    2015-06-01

    Pennsylvania sits atop the Marcellus Shale, a reservoir of natural gas that was untapped until the 2004 introduction of unconventional natural gas drilling operations (UNGDO) in the state. Colloquially known as fracking, UNGDO is a controversial process that employs large volumes of water to fracture the shale and capture gas; it has become a multi-billion dollar industry in Pennsylvania. We analyzed letters to the editor of the most widely circulated local newspaper in the most heavily drilled county in Pennsylvania (Bradford County) in order to characterize residents' concerns and their involvement in popular epidemiology--the process by which citizens investigate risks associated with a perceived environmental threat. We reviewed 215 letters to the editor that referenced natural gas operations and were published by The Daily Review between January 1, 2008 and June 8, 2013. We used NVivo 10 to code and analyze letters and identify major themes. Nvivo is qualitative data analysis software (http://www.qsrinternational.com/products_nvivo.aspx) that allows researchers to code and analyze "unstructured" data, including text files of any type (e.g., interview transcripts, news articles, letters, archival materials) as well as photographs and videos. Nvivo can be used to classify, sort, query, comment on, and share data across a research group. Letters demonstrated citizen engagement in beginning and intermediate stages of lay epidemiology, as well as discord and stress regarding four main issues: socio-economic impacts, perceived threats to water, population growth and implications, and changes to the rural landscape. Residents called for stronger scientific evidence and a balance of economic development and health and environmental protections. Citizens' distress regarding UNGDO appeared to be exacerbated by a dearth of information to guide economic growth and health, environmental, and social concerns. This analysis proposes locally informed questions to guide future

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

    Science.gov (United States)

    Sakitani, Katsumi; Honda, Hiroshi

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

  18. 风力发电机自循环蒸发内冷系统稳定性的研究∗%Static bifurcation analysis of natural circulation inner evap orative co oling system in wind turbine

    Institute of Scientific and Technical Information of China (English)

    王海峰; 李旺; 顾国彪; 沈俊; 滕启治

    2016-01-01

    Wind power is one of the most attractive renewable clean energies under development at present. On a global scale, wind power generation development was very rapid in recent years. As the wind power generation tends to develop toward large-scale and offshore, the traditional cooling methods gradually expose their own shortcomings. As the large wind turbine installation tower is high, and the installation site is dispersed, the installation and maintenance of wind turbine generator are difficult. So, the generator is required to have a small weight and less maintenance. Self-circulation inner evaporative cooling system (SCIECS) has the following advantages: self-circulation without pump, high cooling efficiency, safe and reliable operation, and basically maintain-free, etc. The self-circulation of cooling system can be realized by the 3◦–5◦ between wind turbine generator and the horizontal direction, and it is very suitable for being used in a large-scale wind power generator. Owing to the intrinsic nonlinearity of two-phase self-circulation system, changes of operation condition and circuit topology in a large range may lead to an instability of the cooling system, causing the system parameters to severly change. The instability of the cooling system can cause the local overheating and even burning of the generator, which provides a huge security risk for the cooling system, thus threatening the safe and stable operation of the generator. The stability of SCIECS is very important for the safe operation of wind turbine. In this paper, static stability of the SCIECS in wind power generator is studied based on the nonlinear bifurcation analysis theory and its numerical continuation method. System static bifurcation diagram is obtained to analyze the evolution characteristics of the SCIECS. Parameter effect of the system static bifurcation is analyzed at the same time. In order to verify the theoretical prediction of the static bifurcation of the small-angle two

  19. [Operation of acute dissecting aortic aneurysm in the 25th week of pregnancy using hypothermic extracorporeal circulation].

    Science.gov (United States)

    Thaler, C J; Korell, M; Klinner, U; Reichart, B; Hepp, H

    1992-09-01

    We report on a 24 + 2 weeks pregnant woman with Marfan's syndrome, who acutely developed a dissecting aortic aneurysm with aortic valve insufficiency. Emergency surgery was performed by using hypothermic extracorporeal circulation, whilst the aortic valve and ascending aorta were replaced by a synthetic graft. Foetal heart rates, continuously monitored by using Doppler ultrasound, were shown to be closely correlated with perfusion pressures. By applying perfusion pressures of 90-100 mmHg, we were able to maintain foetal heart rates of approximately 100/min. During the first postoperative day, the CTG was normal for gestational age and no contractions were noted. During the second postoperative night, the patient prematurely delivered a dead 820 g infant (Apgar score 0/0/0/0). In view of this case report, opportunities and problems associated with an application of extracorporeal circulation during pregnancy are discussed.

  20. Circulation economics

    DEFF Research Database (Denmark)

    Ingebrigtsen, Stig; Jakobsen, Ove

    2006-01-01

    Purpose - This paper is an attempt to advance the critical discussion regarding environmental and societal responsibility in economics and business. Design/methodology/approach - The paper presents and discusses as a holistic, organic perspective enabling innovative solutions to challenges...... concerning the responsible and efficient use of natural resources and the constructive interplay with culture. To reach the goal of sustainable development, the paper argues that it is necessary to make changes in several dimensions in mainstream economics. This change of perspective is called a turn towards...... presupposes a perspective integrating economic, natural and cultural values. Third, to organize the interplay between all stakeholders we introduce an arena for communicative cooperation. Originality/value - The paper concludes that circulation economics presupposes a change in paradigm, from a mechanistic...

  1. An ELISA for sensitive and specific detection of circulating antigen of Angiostrongylus vasorum in serum samples of naturally and experimentally infected dogs.

    Science.gov (United States)

    Schnyder, M; Tanner, I; Webster, P; Barutzki, D; Deplazes, P

    2011-06-30

    Canine angiostrongylosis is an emerging cardiopulmonary disease in Europe which can be fatal if left untreated. We developed a sandwich-ELISA based on a monoclonal antibody (mAb Av 56/1/2) and on polyclonal rabbit antibodies directed against Angiostrongylus vasorum adult excretory/secretory - antigen for the detection of circulating serum antigen of A. vasorum. The sensitivity of the test was 95.7% (78.1-99.9, 95% CI) as determined with sera of 23 dogs naturally infected with A. vasorum. The specificity was 94.0% (83.5-98.7, 95% CI) using 50 dog sera (control group) submitted for reasons other than parasitic infections. Potential cross-reactions were investigated with sera of a group of totally 61 dogs with proven infections with Dirofilaria immitis (n=23), Crenosoma vulpis (n=14), Ancylostoma caninum (n=4) or Toxocara canis (n=20). No significant difference was observed concerning the proportion of positive reactions between the control group and the group with proven helminth infections other than A. vasorum. In experimentally inoculated dogs with proven worm burdens of A. vasorum, the proportion of seropositive dogs increased over the first 3 months of infection, starting from 35 days post inoculation (dpi) which was before the onset of larval excretion. Ten weeks post inoculation, 98.6% of the dogs were seropositive, and circulating antigen persisted in two dogs with long-term follow-up over 286 and 356 days, respectively. In contrast, in dogs with a single treatment with imidacloprid/moxidectin at four or 32 dpi, no circulating antigen was observed, while in dogs treated at 88-92 dpi, OD values decreased within 13-34 days. The specific detection of circulating A. vasorum antigen by ELISA represents a valid alternative for reliable diagnosis and for follow-up investigations after anthelmintic treatment. Moreover, the test can be used for mass screening in large epidemiological investigations.

  2. Changes in natural Foxp3(+Treg but not mucosally-imprinted CD62L(negCD38(+Foxp3(+Treg in the circulation of celiac disease patients.

    Directory of Open Access Journals (Sweden)

    Marieke A van Leeuwen

    Full Text Available BACKGROUND: Celiac disease (CD is an intestinal inflammation driven by gluten-reactive CD4(+ T cells. Due to lack of selective markers it has not been determined whether defects in inducible regulatory T cell (Treg differentiation are associated with CD. This is of importance as changes in numbers of induced Treg could be indicative of defects in mucosal tolerance development in CD. Recently, we have shown that, after encounter of retinoic acid during differentiation, circulating gut-imprinted T cells express CD62L(negCD38(+. Using this new phenotype, we now determined whether alterations occur in the frequency of natural CD62L(+Foxp3(+ Treg or mucosally-imprinted CD62L(negCD38(+Foxp3(+ Treg in peripheral blood of CD patients. In particular, we compared pediatric CD, aiming to select for disease at onset, with adult CD. METHODS: Cell surface markers, intracellular Foxp3 and Helios were determined by flow cytometry. Foxp3 expression was also detected by immunohistochemistry in duodenal tissue of CD patients. RESULTS: In children, the percentages of peripheral blood CD4(+Foxp3(+ Treg were comparable between CD patients and healthy age-matched controls. Differentiation between natural and mucosally-imprinted Treg on the basis of CD62L and CD38 did not uncover differences in Foxp3. In adult patients on gluten-free diet and in refractory CD increased percentages of circulating natural CD62L(+Foxp3(+ Treg, but normal mucosally-imprinted CD62L(negCD38(+Foxp3(+ Treg frequencies were observed. CONCLUSIONS: Our data exclude that significant numeric deficiency of mucosally-imprinted or natural Foxp3(+ Treg explains exuberant effector responses in CD. Changes in natural Foxp3(+ Treg occur in a subset of adult patients on a gluten-free diet and in refractory CD patients.

  3. Analysis of Modifications on a Spark Ignition Engine for Operation with Natural Gas

    Directory of Open Access Journals (Sweden)

    Ramasamy D.

    2016-01-01

    Full Text Available Transportation is one of the key contributors to petroleum usage and emissions to the atmosphere. According to researchers, there are many ways to use transport by using renewable energy sources. Of these solutions, the immediate solution which requires less modification to current engine technology is by using gaseous fuels. Natural gas is the fuel of choice for minor modification to current engines. As it can be derived from anaerobic digestion process, the potential as a renewable energy source is tremendous, especially for an agricultural country such a Malaysia. The aim in the future will be operating an engine with natural gas only with pipelines straight to houses for easy filling. The fuel is light and can be easily carried in vehicles when in compressed form. As such, Compressed Natural Gas (CNG is currently used in bi-fuel engines, but is mostly not optimized in term of their performance. The focus of the paper is to optimize a model of natural gas engine by one dimensional flow modeling for operation with natural gas. The model is analyzed for performance and emission characteristics produced by a gasoline engine and later compared with natural gas. The average performance drop is about 15% from its gasoline counterpart. The 4% benchmark indicates that the modification to ignition timing and compression ratio does improve engine performance using natural gas as fuel.

  4. "What if I do nothing?" The natural history of operable cancer of the alimentary tract.

    Science.gov (United States)

    Keshava, H B; Rosen, J E; DeLuzio, M R; Kim, A W; Detterbeck, F C; Boffa, D J

    2017-04-01

    "Natural history", or anticipated survival without treatment, is critical for patients weighing risks and benefits of cancer surgery. Current estimates concerning the natural history of cancer includes patients whose poor health precludes treatment; a cohort whose fate is likely distinctly worse than those eligible for surgery ("operable"). The study objective was to evaluate survival among patients recommended for cancer surgery but went untreated, to determine the natural history of "operable" alimentary tract cancer. The NCDB was queried for untreated patients with clinical stage I-III esophageal, gastric, colon, and rectal cancer diagnosed between 2003 and 2009. Untreated patients who were recommended for surgery were considered "operable," while patients coded as surgically ineligible for health reasons were "inoperable." 5-year survival of untreated, "operable" alimentary tract cancers varied by clinical stage: esophageal cI = 10.0%, cII = 9.8%, cIII = 4.6%; gastric cI = 9.2%, cII = 5.8%, cIII = 4.3%; colon cI = 18.4%, cII = 5.0%, cIII = 10.4; and rectal cI = 17.1%, cII = 14.0%, cIII = 19.9%. At every timepoint, stage-specific survival of "operable" patients was superior to inoperable patients (p < 0.05). Additionally, median survival among "operable" patients at least doubled "inoperable" patients for each tumor. Natural history of patients with "operable" alimentary tract cancer is superior to that of "inoperable" patients. Preoperative counseling should be refined to reflect this distinction. Copyright © 2017 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

  5. 75 FR 17407 - Energy Efficiency of the Natural Gas Infrastructure and Operations Conference; Notice of Public...

    Science.gov (United States)

    2010-04-06

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Energy Efficiency of the Natural Gas Infrastructure and Operations.... Eastern Time, in the Commission Meeting Room on the second floor of the offices of the Federal...

  6. 75 FR 29338 - Energy Efficiency of Natural Gas Infrastructure and Operations Conference; Final Notice of Public...

    Science.gov (United States)

    2010-05-25

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Energy Efficiency of Natural Gas Infrastructure and Operations Conference; Final Notice of Public Conference May 18, 2010. As announced in the ``Notice of Public Conference'' issued on March 31, 2010, a public...

  7. 75 FR 27340 - Energy Efficiency of Natural Gas Infrastructure and Operations Conference; Supplemental Notice of...

    Science.gov (United States)

    2010-05-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Energy Efficiency of Natural Gas Infrastructure and Operations Conference; Supplemental Notice of Public Conference May 3, 2010. As announced in the ``Notice of Public Conference'' issued on March 31, 2010, a...

  8. Some insights in novel risk modeling of liquefied natural gas carrier maintenance operations

    Science.gov (United States)

    Nwaoha, T. C.; John, Andrew

    2016-06-01

    This study discusses the analysis of various modeling approaches and maintenance techniques applicable to the Liquefied Natural Gas (LNG) carrier operations in the maritime environment. Various novel modeling techniques are discussed; including genetic algorithms, fuzzy logic and evidential reasoning. We also identify the usefulness of these algorithms in the LNG carrier industry in the areas of risk assessment and maintenance modeling.

  9. Coordinated Operation of the Electricity and Natural Gas Systems with Bi-directional Energy Conversion

    DEFF Research Database (Denmark)

    Zeng, Qing; Zhang, Baohua; Fang, Jiakun

    2017-01-01

    A coordinated operation of the natural gas and electricity network with bi-directional energy conversion is expected to accommodate high penetration levels of renewables. This work focuses on the unified optimal operation of the integrated natural gas and electricity system considering the network...... constraints in both systems. An iterative method is proposed to deal with the nonlinearity in the proposed model. The models of the natural gas and power system are linearized in every iterative step. Simulation results demonstrate the effectiveness of the approach. Applicability of the proposed method...... is tested in the sample case. Finally, the effect of Power to Gas (P2G) on the daily economic dispatch is also investigated....

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

    Science.gov (United States)

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

    2009-02-01

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

  11. Microwave circulator design

    CERN Document Server

    Linkhart, Douglas K

    2014-01-01

    Circulator design has advanced significantly since the first edition of this book was published 25 years ago. The objective of this second edition is to present theory, information, and design procedures that will enable microwave engineers and technicians to design and build circulators successfully. This resource contains a discussion of the various units used in the circulator design computations, as well as covers the theory of operation. This book presents numerous applications, giving microwave engineers new ideas about how to solve problems using circulators. Design examples are provided, which demonstrate how to apply the information to real-world design tasks.

  12. Brazilian liquefied natural gas terminals: from the conception to the operation

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Renata N.R. dos; Lemos, Marcelo C. de; Silva, Marcos Jose M. da; Borges, Jorge Luiz P.; Soares, Fabio L.; Grieco, Eduardo P.; Melchior, Jose Carlos [PETROBRAS Transporte S.A. (TRANSPETRO), Rio de Janeiro, RJ (Brazil)

    2009-12-19

    To guarantee more flexibility and safety in supplying natural gas to the Brazilian market, PETROBRAS designed and constructed two liquefied natural gas (LNG) regasification terminals. These terminals are unprecedented in the world since they are the only ones to use vessels that have been adapted to store LNG and re gasify the product onboard and to adopt the model of transferring LNG from a supply ship to a regasification vessel via cryogenic arms. Due to these different characteristics, TRANSPETRO, the PETROBRAS subsidiary in charge of operating these terminals, had to prepare itself not only to deal with a new product but also to operate terminals that have no counterparts in the world. This article gives an overview of the LNG supply chain and of the new Brazilian LNG Terminals from their conception to the preparation process to operate them. (author)

  13. 一体化压水堆强迫循环转自然循环过渡过程特性分析%Research on Transition Process From Forced Circulation to Natural Circulation of Integrated Pressurized Water Reactor

    Institute of Scientific and Technical Information of China (English)

    刘守相; 于雷; 鄢炳火

    2012-01-01

    针对一体化压水堆核动力装置,以核动力装置瞬态最佳估算程序RELAP5/MOD3为基础,采用两群三维时空中子动力学模型替代点堆模型,并建立三维空间内中子物理与热工水力的耦合模型,研制相应的计算程序.对一体化核动力装置强迫循环向自然循环转换过程进行仿真模拟.在过渡过程中,一体化压水堆核动力装置反应堆功率变化幅度较大,冷却剂流量的变化对一回路温度影响较大.%The analysis code for an integrated pressurized water reactor was developed on the basis of best-estimate transient analysis code RELAP5/MOD3 for nuclear power plan. The point reactor kinetics model in the original code was replaced by the two-group, 3-D spatial and temporal neutron kinetic model. The coupling model for three-dimensional physics and thermal hydraulic was established. The transition process from forced circulation (FC) to natural circulation (NC) was simulated with this code. During the transition from FC to NC, the variation of reactor power is significant, while the coolant temperature is greatly affected by the coolant flow rate.

  14. Natural Rubber Latex Hypersensitivity with Skin Prick Test in Operating Room Personnel

    Directory of Open Access Journals (Sweden)

    Seyed Hessamedin Nabavizadeh

    2009-12-01

    Full Text Available Hypersensitivity reactions to natural rubber latex have increased recently, especially among people with high exposure to latex allergens. Hypersensitivity reactions to latex are related to many conditions like occupational asthma. Our study was performed to determine the prevalence of hypersensitivity to natural rubber latex and potential food cross reactions in operation room personnel in Shiraz hospitals. In this cross-sectional, descriptive study, 580 operation room personnel filled out our questionnaire which included data about their personal history, symptoms of latex hypersensitivity, and other related allergies such as food hypersensitivity. An informed consent was obtained and skin prick tests were performed for natural rubber latex and potential food cross reactions (kiwi, banana, and potato. The obtained data were analyzed by SPSS and Chi-square test.Results: 104 (17.9% of the operating room personnel showed positive latex skin tests. We revealed a significant correlation between those with positive skin tests to latex with atopia, urthicaria, and food hypersensitivity. The prevalence did not vary by sex, age, education, surgical and non-surgical gloves users, or history of contact dermatitis. Latex hypersensitivity is common among operation room personnel. Evaluation of symptoms and prediction of future diseases necessitate screening tests in individuals at risk.

  15. Restoring Natural Streamflow Variability by Modifying Multi-purpose Reservoir Operation

    Science.gov (United States)

    Shiau, J.

    2010-12-01

    Multi-purpose reservoirs typically provide benefits of water supply, hydroelectric power, and flood mitigation. Hydroelectric power generations generally do not consume water. However, temporal distribution of downstream flows is highly changed due to hydro-peaking effects. Associated with offstream diversion of water supplies for municipal, industrial, and agricultural requirements, natural streamflow characteristics of magnitude, duration, frequency, timing, and rate of change is significantly altered by multi-purpose reservoir operation. Natural flow regime has long been recognized a master factor for ecosystem health and biodiversity. Restoration of altered flow regime caused by multi-purpose reservoir operation is the main objective of this study. This study presents an optimization framework that modifying reservoir operation to seeking balance between human and environmental needs. The methodology presented in this study is applied to the Feitsui Reservoir, located in northern Taiwan, with main purpose of providing stable water-supply and auxiliary purpose of electricity generation and flood-peak attenuation. Reservoir releases are dominated by two decision variables, i.e., duration of water releases for each day and percentage of daily required releases within the duration. The current releasing policy of the Feitsui Reservoir releases water for water-supply and hydropower purposes during 8:00 am to 16:00 pm each day and no environmental flows releases. Although greater power generation is obtained by 100% releases distributed within 8-hour period, severe temporal alteration of streamflow is observed downstream of the reservoir. Modifying reservoir operation by relaxing these two variables and reserve certain ratio of streamflow as environmental flow to maintain downstream natural variability. The optimal reservoir releasing policy is searched by the multi-criterion decision making technique for considering reservoir performance in terms of shortage ratio

  16. Multiobjective optimization of the operation of a liquid-solid circulating fluidized bed ion-exchange system for continuous protein recovery.

    Science.gov (United States)

    Mazumder, Jahirul; Zhu, Jingxu; Bassi, Amarjeet S; Ray, Ajay K

    2009-08-01

    Like most real-life processes, the operation of liquid-solid circulating fluidized bed (LSCFB) system for continuous protein recovery is associated with several objectives such as maximization of production rate and recovery of protein, and minimization of amount solid ion-exchange resin requirement, all of which need to be optimized simultaneously. In this article, multiobjective optimization of a LSCFB system for continuous protein recovery was carried out using an experimentally validated mathematical model to find the scope for further improvements in its operation. Elitist non-dominated sorting genetic algorithm with its jumping gene adaptation was used to solve a number of bi- and tri-objective function optimization problems. The optimization resulted in Pareto-optimal solution, which provides a broad range of non-dominated solutions due to conflicting behavior of the operating parameters on the system performance indicators. Significant improvements were achieved, for example, the production rate at optimal operation increased by 33%, using 11% less solid compared to reported experimental results for the same recovery level. The effects of operating variables on the optimal solutions are discussed in detail. The multiobjective optimization study reported here can be easily extended for the improvement of LSCFB system for other applications.

  17. Identifying emerging smart grid impacts to upstream and midstream natural gas operations.

    Energy Technology Data Exchange (ETDEWEB)

    McIntyre, Annie

    2010-09-01

    The Smart Grid has come to describe a next-generation electrical power system that is typified by the increased use of communications and information technology in the generation, delivery and consumption of electrical energy. Much of the present Smart Grid analysis focuses on utility and consumer interaction. i.e. smart appliances, home automation systems, rate structures, consumer demand response, etc. An identified need is to assess the upstream and midstream operations of natural gas as a result of the smart grid. The nature of Smart Grid, including the demand response and role of information, may require changes in upstream and midstream natural gas operations to ensure availability and efficiency. Utility reliance on natural gas will continue and likely increase, given the backup requirements for intermittent renewable energy sources. Efficient generation and delivery of electricity on Smart Grid could affect how natural gas is utilized. Things that we already know about Smart Grid are: (1) The role of information and data integrity is increasingly important. (2) Smart Grid includes a fully distributed system with two-way communication. (3) Smart Grid, a complex network, may change the way energy is supplied, stored, and in demand. (4) Smart Grid has evolved through consumer driven decisions. (5) Smart Grid and the US critical infrastructure will include many intermittent renewables.

  18. Fetal Circulation

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Fetal Circulation Updated:Oct 18,2016 click to enlarge The ... fetal heart. These two bypass pathways in the fetal circulation make it possible for most fetuses to survive ...

  19. Operator Splitting Method for Simulation of Dynamic Flows in Natural Gas Pipeline Networks

    CERN Document Server

    Dyachenko, Sergey A; Chertkov, Michael

    2016-01-01

    We develop an operator splitting method to simulate flows of isothermal compressible natural gas over transmission pipelines. The method solves a system of nonlinear hyperbolic partial differential equations (PDEs) of hydrodynamic type for mass flow and pressure on a metric graph, where turbulent losses of momentum are modeled by phenomenological Darcy-Weisbach friction. Mass flow balance is maintained through the boundary conditions at the network nodes, where natural gas is injected or withdrawn from the system. Gas flow through the network is controlled by compressors boosting pressure at the inlet of the adjoint pipe. Our operator splitting numerical scheme is unconditionally stable and it is second order accurate in space and time. The scheme is explicit, and it is formulated to work with general networks with loops. We test the scheme over range of regimes and network configurations, also comparing its performance with performance of two other state of the art implicit schemes.

  20. Operational and contractual impacts in E and P offshore during predicted natural hazards

    Energy Technology Data Exchange (ETDEWEB)

    Benevides, Paulo Roberto Correa de Sa e [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    Generally, when E and P operators using DP (Dynamic Positioning) are advised previously of a possible natural hazard occurrence, usually they consider it like an emergency situation and their main action is oriented only to prepare the first response and use the 'force majeure' argumentation to protect itself from any additional responsibility. When the natural phenomenon actually happens, the expenses due to the losses will be accepted because it was already considered in its budget as 'Losses due to accident' and it will be shared by the partners of the project according to the correspondent contractual terms. This paper describes real cases of the evolution of predictions for natural hazards in offshore basins in Brazil, Western Africa and Gulf of Mexico where PETROBRAS and many other oil companies have used DP operations. It proposes some alternative procedures through the BCM (Business Continuity Management) to manage natural crisis instead of the common use of the traditional 'force majeure' argumentation. (author)

  1. Expansion of circulating CD56bright natural killer cells in patients with JAK2-positive chronic myeloproliferative neoplasms during treatment with interferon-α

    DEFF Research Database (Denmark)

    Riley, Caroline H; Hansen, Morten; Brimnes, Marie K

    2015-01-01

    -tumor immune response against the JAK2-mutated clone. The objective of this study was to investigate circulating levels and phenotype of natural killer cells in 29 JAK2-positive MPN patients during IFN-α treatment. Furthermore, functional studies of NK cells upon target-cell recognition and cytokine......In recent years, major molecular remissions have been observed in patients with JAK2-positive chronic myeloproliferative neoplasms (MPNs) after therapy with IFN-α. IFN-α is known to have altering effects on immune cells involved in immune surveillance and might consequently enhance anti...... stimulation were performed. The CD56(bright) and CD56(dim) NK cell subtypes display different properties in terms of cytokine production and cytotoxicity, respectively. Our results show a significant increase in the proportion of CD56(bright) NK cells and a decreasing CD56(dim) population during treatment...

  2. Extracting important information from Chinese Operation Notes with natural language processing methods.

    Science.gov (United States)

    Wang, Hui; Zhang, Weide; Zeng, Qiang; Li, Zuofeng; Feng, Kaiyan; Liu, Lei

    2014-04-01

    Extracting information from unstructured clinical narratives is valuable for many clinical applications. Although natural Language Processing (NLP) methods have been profoundly studied in electronic medical records (EMR), few studies have explored NLP in extracting information from Chinese clinical narratives. In this study, we report the development and evaluation of extracting tumor-related information from operation notes of hepatic carcinomas which were written in Chinese. Using 86 operation notes manually annotated by physicians as the training set, we explored both rule-based and supervised machine-learning approaches. Evaluating on unseen 29 operation notes, our best approach yielded 69.6% in precision, 58.3% in recall and 63.5% F-score. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Effect of Coolant Inventories and Parallel Loop Interconnections on the Natural Circulation in Various Heat Transport Systems of a Nuclear Power Plant during Station Blackout

    Directory of Open Access Journals (Sweden)

    Avinash J. Gaikwad

    2008-01-01

    Full Text Available Provision of passive means to reactor core decay heat removal enhances the nuclear power plant (NPP safety and availability. In the earlier Indian pressurised heavy water reactors (IPHWRs, like the 220 MWe and the 540 MWe, crash cooldown from the steam generators (SGs is resorted to mitigate consequences of station blackout (SBO. In the 700 MWe PHWR currently being designed an additional passive decay heat removal (PDHR system is also incorporated to condense the steam generated in the boilers during a SBO. The sustainability of natural circulation in the various heat transport systems (i.e., primary heat transport (PHT, SGs, and PDHRs under station blackout depends on the corresponding system's coolant inventories and the coolant circuit configurations (i.e., parallel paths and interconnections. On the primary side, the interconnection between the two primary loops plays an important role to sustain the natural circulation heat removal. On the secondary side, the steam lines interconnections and the initial inventory in the SGs prior to cooldown, that is, hooking up of the PDHRs are very important. This paper attempts to open up discussions on the concept and the core issues associated with passive systems which can provide continued heat sink during such accident scenarios. The discussions would include the criteria for design, and performance of such concepts already implemented and proposes schemes to be implemented in the proposed 700 MWe IPHWR. The designer feedbacks generated, and critical examination of performance analysis results for the added passive system to the existing generation II & III reactors will help ascertaining that these safety systems/inventories in fact perform in sustaining decay heat removal and augmenting safety.

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

    Directory of Open Access Journals (Sweden)

    Renato Sathler-Avelar

    2016-01-01

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

  5. Theoretical investigations of the operating characteristics of circulating pressurized fluidized bed combustors; Theoretische Untersuchungen zum Betriebsverhalten zirkulierender Druckwirbelschichtfeuerungen

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, M.; Krumm, W.

    1999-07-01

    The combination of gas turbine and water-/steam cycle is a proper alternative to increase the efficiency of power plants. Coal fired power plants can be designed as reactors with pressurized coal gasification, pressurized coal dust combustion or a pressurized fluidized bed combustion to realize these plant design. Mathematical modeling and simulation are used to support the development of new power plant concepts, e.g. pressurized fluidized bed combustion. In this paper a one-dimensional model for a pressurized fluidized circulating bed combustion power plant is presented. The modeling structure allows to vary different parameters to identify the particular influence on the overall plant behavior. The model is enlarged by a more detailed balance for limestone. After describing the theoretical background of the influence of added limestone rate on the emissions of sulfurdioxide is shown. (orig.) [German] Ausgehend vom Prinzip eines Dampfkraftwerks mit atmosphaerischer Wirbelschichtfeuerung werden der Dampf- und Gasturbinenprozess bei den druckaufgeladenen Konzepten quasi parallel betrieben und die Gasturbine mit dem Rauchgas aus der Kohlenfeuerung beaufschlagt. Die wesentlichen Unterschiede zu erdgas- oder oelbefeuerten Kombianlagen sind bei den Druckwirbelschichtkonzepten, durch den in Zusammensetzung und Feuchtegehalt stark variierenden Brennstoff Kohle und durch die Auskopplung grosser Waermemengen bei der integrierten Dampferzeugung, gegeben. Der Hauptanteil der erzeugten elektrischen Leistung entfaellt auf den Dampfturbinenprozess. Druckwirbelschichtanlagen mit blasenbildender Wirbelschicht sind seit Anfang der 90er Jahre in Betrieb. Entsprechend der Entwicklung bei der atmopshaerischen Wirbelschichtfeuerung zeichnet sich als naechste Generation dieses Kraftwerkstyps die zirkulierende Druckwirbelschicht mit Heissgasfilter ab. Die mathematische Modellbildung hat sich zu einem anerkannten Werkzeug zur Unterstuetzung der Auslegung und der Untersuchung der Wirkung

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

    Science.gov (United States)

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

    2010-01-01

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

  7. 33 CFR 165.1709 - Security Zones: Liquefied Natural Gas Tanker Transits and Operations at Phillips Petroleum LNG...

    Science.gov (United States)

    2010-07-01

    ... Gas Tanker Transits and Operations at Phillips Petroleum LNG Pier, Cook Inlet, AK. 165.1709 Section...: Liquefied Natural Gas Tanker Transits and Operations at Phillips Petroleum LNG Pier, Cook Inlet, AK. (a... navigable waters within a 1000-yard radius of the Liquefied Natural Gas (LNG) tankers during their...

  8. [Cardioprotective effects of glutamine in patients with ischemic heart disease operated under conditions of extracorporeal blood circulation].

    Science.gov (United States)

    Lomivorotov, V V; Efremov, S M; Shmyrev, V A; Ponomarev, D N; Sviatchenko, A V; Kniaz'kova, L G

    2012-01-01

    It was conducted a study of glutamine cardioptotective effects during perioperative use in patients with ischemic heart disease, operated under CB. Exclusion criteria were: left ventricular ejection fraction less than 50%, diabetes melitus, myocardial infarction less than 3 months ago, Patients of the study group (n=25) had glutamine (20% solution N(2)-L-alanine-L-glutamine ("Dipeptiven" Fresenius Kabi, Germany); 0.4 g/kg/day. Patients of control group (n=25) received placebo (0.9% NaCl solution). The main indicators were the dynamics of troponin I, as well as central hemodynamics parameters. On the 1-st day after operation the concentration of troponin I was significantly lower in the glutamine-group compared placebo-group (1.280 (0.840-2.230) 2.410 (1.060-6.600) ng/ml; p=0.035). 4 hours after CB in a glutamine-group also had significantly large indicators of cardiac index (2.58 (2.34-2.91) l/min/m2 vs 2.03 (1.76-2.32)) l/min/m2; p=0,002) and stroke index (32.8 (27.8-36.0.) ml/m2 vs 26.1 (22.6-31.8) ml/m2; p=0.023). Systemic vascular resistance index was significantly lower in glutamine-group (1942 (1828-2209) dyn x s/cm(-5)/m2 vs 2456 (2400-3265) dyn x s/cm(-5)/m2; p=0.001). Conclusion. Perioperative use of N(2)-L-alanine-L-glutamine during the first 24 hours ofperioperative period gives cardioprotective effect in patients with ischemic heart disease operated under CB.

  9. 33 CFR 165.110 - Safety and Security Zone; Liquefied Natural Gas Carrier Transits and Anchorage Operations, Boston...

    Science.gov (United States)

    2010-07-01

    ...; Liquefied Natural Gas Carrier Transits and Anchorage Operations, Boston, Massachusetts. 165.110 Section 165... Limited Access Areas First Coast Guard District § 165.110 Safety and Security Zone; Liquefied Natural Gas... ahead and one mile astern, and 500 yards on each side of any liquefied natural gas carrier (LNGC)...

  10. 78 FR 53190 - Pipeline Safety: Notice to Operators of Hazardous Liquid and Natural Gas Pipelines of a Recall on...

    Science.gov (United States)

    2013-08-28

    ... Liquid and Natural Gas Pipelines of a Recall on Leak Repair Clamps Due to Defective Seal AGENCY: Pipeline... seal. Hazardous liquid and natural gas pipeline operators should ] verify if they have any TDW LRCs... and Flanged Fittings. These LRCs were manufactured for use on hazardous liquid and natural...

  11. Access of Digitized Print Originals in US and UK Higher Education Libraries Combined with Print Circulation Indicates Increased Usage of Traditional Forms of Reading Materials. A Review of: Joint, Nicholas. “Is Digitisation the New Circulation?: Borrowing Trends, Digitisation and the nature of reading in US and UK Libraries.” Library Review 57.2 (2008: 87-95.

    Directory of Open Access Journals (Sweden)

    Kurt Blythe

    2009-03-01

    libraries, while it is up in the non-ARL higher education libraries represented and in UK higher education libraries. However, audio book circulation in US public libraries supplements print circulation to the point where overall circulation of book materials is increasing, and the access of digital literature supplements print circulation in ARL member libraries (although the statistics are difficult to measure and meld with print circulation statistics. Essentially, the circulation of book material is increasing in most institutions when all formats are considered. According to the author, library patrons are reading more than ever; the materials patrons are accessing are traditional in content regardless of the means by which the materials are accessed.Conclusion – The author contends that print circulation is in decline only where digitization efforts are extensive, such as in ARL-member libraries; when digital content is factored into the equation the access of book-type materials is up in most libraries. The author speculates that whether library patrons use print or digital materials, the content of those materials is largely traditional in nature, thereby resulting in the act of “literary” reading remaining a focal point of library usage. Modes of reading and learning have not changed, at least insofar as these things may be inferred from studying circulation statistics. The author asserts that digital access is favorable to patrons and that libraries should attempt to follow the ARL model of engaging in large scale digitization projects in order to provide better service to their patrons; the author goes on to argue that UK institutions with comparable funding to ARLs will have greater success in this endeavour if UK copyright laws are relaxed.

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

    Science.gov (United States)

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

    2017-01-01

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

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

    Science.gov (United States)

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

    2017-03-12

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

  14. Operation modes research of liquefied natural gas storages as a part of the ground complexes equipment

    Directory of Open Access Journals (Sweden)

    N. S. Korolev

    2014-01-01

    Full Text Available The use of the Liquefied Natural Gas (LNG in the space-rocket equipment is motivated by some advantages. That is why a lot of tests and works are actively carried out now on rocket engines using liquefied natural gas.To provide the engine tests and subsequent rocket complex operation a creation of LNG storages is demanded as a part of ground processing equipment and support for their safe operation conditions.One of LNG danger factor is its low boiling temperature, and also changing the condition, density and LNG boiling temperature at storage due to evaporation of light component, namely methane. At refill of the storages having fuel remains with a new LNG portion these factors can lead to formation of the stratified macro-layers and cause a mode of the intensive mixing that is called "rollover", with almost instant evaporation of LNG big mass and sharp pressure boost, capable to result in the storage distraction with catastrophic effects.The work objectives are formulated such as a technique development for forecasting of the LNG parameters in operating storages including the rollover mode, a comparison of calculated results of the LNG parameters with the experimental data, and a definition of possible recommendations for safe operation of LNG storages as a part of the ground complexes equipment.The paper reviews 12 publications concerning the issues and proceeding processes at operation of LNG storages, including the rollover mode.To verify the reliability of process simulation results in the LNG, represented in models by the binary methane-ethane mixture the calculated values have been compared with the experimental data for a LNG storage mode in the reservoir of a ground test complex.The reliability of developed models of the heat-mass-exchange processes in stratified on density and temperature in LNG storage with emergence of conditions for the rollover mode has been verified by comparing the settlement characteristics to the published

  15. TECHNOLOGIES TO ENHANCE THE OPERATION OF EXISTNG NATURAL GAS COMPRESSION INFRASTRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn; Danny M. Deffenbaugh

    2005-01-28

    This quarterly report documents work performed under Tasks 15, 16, and 18 through 23 of the project entitled: ''Technologies to Enhance the Operation of the Existing Natural Gas Compression Infrastructure''. The project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity. The report first documents a survey test performed on an HBA-6 engine/compressor installed at Duke Energy's Bedford Compressor Station. This is one of several tests planned, which will emphasize identification and reduction of compressor losses. Additionally, this report presents a methodology for distinguishing losses in compressor attributable to valves, irreversibility in the compression process, and the attached piping (installation losses); it illustrates the methodology with data from the survey test. The report further presents the validation of the simulation model for the Air Balance tasks and outline of conceptual manifold designs.

  16. TECHNOLOGIES TO ENHANCE THE OPERATION OF EXISTING NATURAL GAS COMPESSION INFRASTRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn; Danny M. Deffenbaugh

    2006-01-24

    This quarterly report documents work performed under Tasks 15, 16, and 18 through 23 of the project entitled: ''Technologies to Enhance the Operation of Existing Natural Gas Compression Infrastructure''. The project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity. The report presents results of design analysis performed on the TCVC10 engine/compressor installed at Dominion's Groveport Compressor Station to develop options and guide decisions for reducing pulsations and enhancing compressor system efficiency and capacity. The report further presents progress on modifying and testing the laboratory GMVH6 at SwRI for correcting air imbalance.

  17. Hydrogen and Hydrogen/Natural Gas Station and Vehicle Operations - 2006 Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Francfort; Donald Karner; Roberta Brayer

    2006-09-01

    This report is a summary of the operations and testing of internal combustion engine vehicles that were fueled with 100% hydrogen and various blends of hydrogen and compressed natural gas (HCNG). It summarizes the operations of the Arizona Public Service Alternative Fuel Pilot Plant, which produces, compresses, and dispenses hydrogen fuel. Other testing activities, such as the destructive testing of a CNG storage cylinder that was used for HCNG storage, are also discussed. This report highlights some of the latest technology developments in the use of 100% hydrogen fuels in internal combustion engine vehicles. Reports are referenced and WWW locations noted as a guide for the reader that desires more detailed information. These activities are conducted by Arizona Public Service, Electric Transportation Applications, the Idaho National Laboratory, and the U.S. Department of Energy’s Advanced Vehicle Testing Activity.

  18. Natural Airfield Pavements, Load-Carrying Capacities There Of, Principles Of Construction And Operational Use

    Directory of Open Access Journals (Sweden)

    Nita Piotr

    2015-09-01

    Full Text Available The paper has been intended to present analytically derived relationships for aircraft wheels that move through the soil medium. The analyses have been conducted for both the rigid wheel and the pneumatic whell. The most fundamental principles of constructing natural(soil and sod/grass airfield pavements have been diccussed. Characteristic of soils typical of such pavements /surfaces have been defined. Proped are criteria for the evaluation of load-carring capacities of such pavements. The most essential principles that goven the operational use there of follow.

  19. Nearshore circulation

    NARCIS (Netherlands)

    Battjes, J.A.; Sobey, R.J.; Stive, M.J.F.

    1990-01-01

    Shelf circulation is driven primarily by wind- and tide-induced forces. It is laterally only weakly constrained so that the geostrophic (Coriolis) acceleration is manifest in the response. Nearshore circulation on the other hand is dominated by wave-induced forces associated with shallow-water. wave

  20. 自然循环汽包炉蒸发回路稳态数学模型%A Steady-state Model of Drum-downcomer-riser Loop in Natural Circulation Drum-type Boilers

    Institute of Scientific and Technical Information of China (English)

    刘福国; 何传怀

    2014-01-01

    A steady-state model was developed which gave detailed account of the thermal-hydraulic phenomena in down-comer-riser-drum loop of a natural circulation drum-type boiler. The model was composed of mass, energy and momentum conservation equations, together with algebraic relationships to describe the working fluids properties and phase change. The empirical relative distribution of heat flux along the height of the furnace was used to drive the model, the averaged heat flux in furnace was solved as unknown, and this fairly accords with the physical process. The model is capable of predicting working fluids temperature, pressure, circulation flow-rates and steam distributions in risers under various operating conditions. Results of the simulation provide a clear insight into two-phase flow and heat transfer conditions in evaporating tubes, and predicated circulation ratios are consistent with results obtained in other literatures.%建立了自然循环汽包炉下降管-上升管-汽包回路的稳态数学模型,该模型是由物质、能量和动量微分方程以及工质物性和相变代数方程组成,炉膛相对热负荷沿高度的一维经验分布作为模型的驱动方程,炉膛平均热负荷是求解变量,因此,热负荷不是独立变量,它与汽包产生的蒸汽量相关,这与实际物理过程较好地相符。该模型能够预测不同运行状态下工质在上升管内的压力、温度、循环流量以及含汽率分布,模拟结果给出了蒸发管内两相流动和传热的清晰图景,循环倍率的预测值与有关文献给出的结果相一致。

  1. The identification of blood circulation in the operation of free flap transplantation%游离皮瓣移植术中血液循环判断

    Institute of Scientific and Technical Information of China (English)

    顾加祥; 田恒; 张乃臣; 刘宏君; 潘俊博; 董佳生

    2012-01-01

    Objective To explore the significance of identifying blood circulation in the operation of free flap transplantation to a successful flap surgery. Methods Twenty - six patients who suffered from trauma and soft tissue loss in our hospital from Mar. 2007 to Dec. 2009 received free skin flap transplantation with latissimus dorsi muscle and thigh anterolatera flap. The correlation between flap flexibility, color, the color of the venous blood, and flap survival after surgery were observed. Results After surgery, it was found that the flap survival was good if the flap flexibility and the color of the flap had the same color with the donor area and the venous blood became mauve. Conclusion The identification of blood circulation in the operation of free flap transplantation is important to a successful flap surgery.%目的 探讨游离皮瓣移植术中血液循环判断对皮瓣手术成功的指导意义.方法 对2007年3月~2009年12月26例外伤后皮肤和软组织缺损的患者行游离背阔肌和股前外侧皮瓣移植,观察术中吻合血管后皮瓣的弹性、色泽,吻合处静脉血流的颜色和术后皮瓣的存活之间的关系.结果 游离皮瓣移植术中吻合血管后,如皮瓣的弹性正常、色泽逐渐转为原供区切取前色泽,静脉血流颜色转为(淡)紫红色,则皮瓣术后存活良好.结论 游离皮瓣移植术中静脉血流和皮瓣颜色等血液循环的判断对皮瓣存活有重要的参考的意义.

  2. Application of Hydrogen Assisted Lean Operation to Natural Gas-Fueled Reciprocating Engines (HALO)

    Energy Technology Data Exchange (ETDEWEB)

    Chad Smutzer

    2006-01-01

    Two key challenges facing Natural Gas Engines used for cogeneration purposes are spark plug life and high NOx emissions. Using Hydrogen Assisted Lean Operation (HALO), these two keys issues are simultaneously addressed. HALO operation, as demonstrated in this project, allows stable engine operation to be achieved at ultra-lean (relative air/fuel ratios of 2) conditions, which virtually eliminates NOx production. NOx values of 10 ppm (0.07 g/bhp-hr NO) for 8% (LHV H2/LHV CH4) supplementation at an exhaust O2 level of 10% were demonstrated, which is a 98% NOx emissions reduction compared to the leanest unsupplemented operating condition. Spark ignition energy reduction (which will increase ignition system life) was carried out at an oxygen level of 9%, leading to a NOx emission level of 28 ppm (0.13 g/bhp-hr NO). The spark ignition energy reduction testing found that spark energy could be reduced 22% (from 151 mJ supplied to the coil) with 13% (LHV H2/LHV CH4) hydrogen supplementation, and even further reduced 27% with 17% hydrogen supplementation, with no reportable effect on NOx emissions for these conditions and with stable engine torque output. Another important result is that the combustion duration was shown to be only a function of hydrogen supplementation, not a function of ignition energy (until the ignitability limit was reached). The next logical step leading from these promising results is to see how much the spark energy reduction translates into increase in spark plug life, which may be accomplished by durability testing.

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

    Science.gov (United States)

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

    2015-12-01

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

  4. Input Calibration and Validation of RELAP5 Against CIRCUS-IV Single Channel Tests on Natural Circulation Two-Phase Flow Instability

    Directory of Open Access Journals (Sweden)

    Viet-Anh Phung

    2015-01-01

    Full Text Available RELAP5 is a system thermal-hydraulic code that is used to perform safety analysis on nuclear reactors. Since the code is based on steady state, two-phase flow regime maps, there is a concern that RELAP5 may provide significant errors for rapid transient conditions. In this work, the capability of RELAP5 code to predict the oscillatory behavior of a natural circulation driven, two-phase flow at low pressure is investigated. The simulations are compared with a series of experiments that were performed in the CIRCUS-IV facility at the Delft University of Technology. For this purpose, we developed a procedure for calibration of the input and code validation. The procedure employs (i multiple parameters measured in different regimes, (ii independent consideration of the subsections of the loop, and (iii assessment of importance of the uncertain input parameters. We found that predicted system parameters are less sensitive to variations of the uncertain input and boundary conditions in high frequency oscillations regime. It is shown that calculation results overlap experimental values, except for the high frequency oscillations regime where the maximum inlet flow rate was overestimated. This finding agrees with the idea that steady state, two-phase flow regime maps might be one of the possible reasons for the discrepancy in case of rapid transients in two-phase systems.

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

    Science.gov (United States)

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

    2014-03-01

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

  6. Diluted Operation of a Heavy-Duty Natural Gas Engine - Aiming at Improved Effciency, Emission and Maximum Load

    OpenAIRE

    Kaiadi, Mehrzad

    2011-01-01

    Most heavy-duty engines are diesel operated. Severe emission regulations, high fuel prices, high technology costs (e.g. catalysts, fuel injection systems) and unsustainably in supplying fuel are enough reasons to convenience engine developers to explore alternative technologies or fuels. Using natural gas/biogas can be a very good alternative due to the attractive fuel properties regarding emission reduction and engine operation. Heavy-duty diesel engines can be easily converted for natur...

  7. Effectiveness of Operation of Organic Rankine Cycle Installation Applied in the Liquid Natural Gas Regasification Plant

    Science.gov (United States)

    Kaczmarek, R.; Stachel, A. A.

    2017-05-01

    An analysis of the operation of an Organic Rankine Cycle (ORC) installation heated by a low-temperature heat source is presented for the case where a condenser of a working fluid is cooled by a liquid of ultralow temperature. For this purpose, the process of regasification of liquid natural gas (LNG) is considered. In the process, the condensation heat of the working fluid in ORC is taken by the LNG evaporating subsequently (i.e., undergoing regasification). The paper presents the schematic of this installation and its application, as well as the results of calculations on the basis of the analysis in terms of the power and efficiency. In the analysis, organic fluids used in the ORC as working ones have been selected.

  8. Numerical Simulations of a Prechamber Autoignition Engine Operating on Natural Gas

    Directory of Open Access Journals (Sweden)

    Daniel Favrat

    2011-05-01

    Full Text Available

    At our laboratory extensive research has been conducted on the conversion of conventional Diesel cogeneration engines to operation on natural gas and biogas. In the framework of this research, a numerical simulation of a prechamber autoignition gas engine has been performed based on an experimental test case. With a simplified finite-rate/eddy-dissipation model for the combustion of natural gas, it was possible to properly reproduce the experiment considering the combustion duration, ignition timing and overall energy balance. A modification of the original cylindrical-conical prechamber geometry to a simpler cylindrical one was tested with the simulation model. The influence of burnt gases inside the prechamber was assessed simulating the mixture formation inside the prechamber. The simulations showed little effect of taking into account the non-homogeneities in the gas phase on the combustion duration. The new cylindrical geometry envisaged did not show any improvement in the combustion homogeneity inside the prechamber and its volume (limited by the real engine geometry is in fact not sufficient to properly ignite the main chamber according to the simulations. The model can be used to further guide design modifications of the prechamber engine to improve performance.


  9. Metrological and operational performance of measuring systems used in vehicle compressed natural gas filling stations

    Energy Technology Data Exchange (ETDEWEB)

    Velosa, Jhonn F.; Abril, Henry; Garcia, Luis E. [CDT de GAS (Venezuela). Gas Technological Development Center Corporation

    2008-07-01

    Corporation CDT GAS financially supported by the Colombian government through COLCIENCIAS, carried out a study aimed at designing, developing and implementing in Colombia a calibration and metrological verification 'specialized service' for gas meters installed at dispensers of filling stations using compressed natural gas. The results permitted the identification of improving opportunities (in measuring systems, equipment and devices used to deliver natural gas) which are focused on achieving the highest security and reliability of trading processes of CNG for vehicles. In the development of the first stage of the project, metrological type variables were initially considered, but given the importance of the measuring system and its interaction with the various elements involving gas supply to the filling station, the scope of the work done included aspects related to the operational performance, that is, those influencing the security of the users and the metrological performance of the measuring system. The development of the second stage counted on the collaboration of national companies from the sector of CNG for vehicles, which permitted the carrying out of multiple calibrations to the measuring systems installed in the CNG dispensers, thus achieving, in a concrete way, valid and reliable technological information of the implemented procedures. (author)

  10. TECHNOLOGIES TO ENHANCE OPERATION OF THE EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn; Danny M. Deffenbaugh

    2005-01-01

    This quarterly report documents work performed under Tasks 10 through 14 of the project entitled: ''Technologies to Enhance Operation of the Existing Natural Gas Compression Infrastructure''. The project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity. The report first documents tests performed on a KVG103 engine/compressor installed at Duke's Thomaston Compressor Station. This is the first series of tests performed on a four-stroke engine under this program. Additionally, this report presents results, which complete a comparison of performance before and after modification to install High Pressure Fuel Injection and a Turbocharger on a GMW10 at Williams Station 60. Quarterly Reports 7 and 8 already presented detailed data from tests before and after this modification, but the final quantitative comparison required some further analysis, which is presented in Section 5 of this report. The report further presents results of detailed geometrical measurements and flow bench testing performed on the cylinders and manifolds of the Laboratory Cooper GMVH6 engine being employed for two-stroke engine air balance investigations. These measurements are required to enhance the detailed accuracy in modeling the dynamic interaction of air manifold, exhaust manifold, and in-cylinder fuel-air balance.

  11. Flared natural gas-based onsite atmospheric water harvesting (AWH) for oilfield operations

    Science.gov (United States)

    Wikramanayake, Enakshi D.; Bahadur, Vaibhav

    2016-03-01

    Natural gas worth tens of billions of dollars is flared annually, which leads to resource waste and environmental issues. This work introduces and analyzes a novel concept for flared gas utilization, wherein the gas that would have been flared is instead used to condense atmospheric moisture. Natural gas, which is currently being flared, can alternatively power refrigeration systems to generate the cooling capacity for large scale atmospheric water harvesting (AWH). This approach solves two pressing issues faced by the oil-gas industry, namely gas flaring, and sourcing water for oilfield operations like hydraulic fracturing, drilling and water flooding. Multiple technical pathways to harvest atmospheric moisture by using the energy of natural gas are analyzed. A modeling framework is developed to quantify the dependence of water harvest rates on flared gas volumes and ambient weather. Flaring patterns in the Eagle Ford Shale in Texas and the Bakken Shale in North Dakota are analyzed to quantify the benefits of AWH. Overall, the gas currently flared annually in Texas and North Dakota can harvest enough water to meet 11% and 65% of the water consumption in the Eagle Ford and the Bakken, respectively. Daily harvests of upto 30 000 and 18 000 gallons water can be achieved using the gas currently flared per well in Texas and North Dakota, respectively. In fifty Bakken sites, the water required for fracturing or drilling a new well can be met via onsite flared gas-based AWH in only 3 weeks, and 3 days, respectively. The benefits of this concept are quantified for the Eagle Ford and Bakken Shales. Assessments of the global potential of this concept are presented using data from countries with high flaring activity. It is seen that this waste-to-value conversion concept offers significant economic benefits while addressing critical environmental issues pertaining to oil-gas production.

  12. 压力容器外部冷却两相自然循环特性理论分析%Theoretical analysis of the properties of the two-phase natural circulation of ERVC

    Institute of Scientific and Technical Information of China (English)

    赵国志; 曹欣荣; 石兴伟

    2014-01-01

    针对严重事故下压水堆压力容器下封头外侧与绝热层内侧环形通道内两相自然循环流动问题,利用FORTRAN语言,编写了压水堆压力容器外部冷却( external reactor vessel cooling, ERVC)一维稳态自然循环分析程序。通过分析不同摩擦系数的计算公式对两相自然循环质量流量和空泡份额计算的影响,与中国开展的REPEC( reactor pressure vessel external cooling)实验及RELAP5模拟结果对比,验证了程序的可行性。对ERVC系统重要的热工水力和结构参数进行了敏感性分析,得到结论:进口过冷度对ERVC系统内两相流量影响很大,当过冷度接近饱和值时,流量会出现峰值,进口面积、间隙宽度和水淹高度会影响质量流量峰值的大小;当过冷度高于峰值对应的过冷度,流量随过冷度增大而减小,反之随过冷度增大而增大。结果可为ERVC系统的设计和运行参数的评估提供了一种简便快速的方法。%Focusing on the problem of two-phase natural circulation flow inside the loop-shape passage between the outside of the lower head of the reactor vessel and the inside of the insulator in times of severe accidents, an analy-sis program for one-dimensional steady-state natural circulation under the external reactor vessel cooling ( ERVC ) condition was done by utilizing the FORTRAN language. The effects of the calculation formulae of different friction coefficients on mass flow and void fraction of the two-phase natural circulation flow were studied. The results were compared with those obtained in the Chinese REPEC ( reactor pressure vessel external cooling) experiment and the RELAP5 simulation, and the feasibility of the program was demonstrated. A sensitivity analysis was performed for the important thermal-hydraulic and configuration parameters of the ERVC system, and the following conclusion was obtained:The inlet subcooling has a significant impact on the two

  13. TECHNOLOGIES TO ENHANCE THE OPERATION OF EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn; Ford A. Phillips; Danny M. Deffenbaugh

    2006-05-31

    This project has documented and demonstrated the feasibility of technologies and operational choices for companies who operate the large installed fleet of integral engine compressors in pipeline service. Continued operations of this fleet is required to meet the projected growth of the U.S. gas market. Applying project results will meet the goals of the DOE-NETL Natural Gas Infrastructure program to enhance integrity, extend life, improve efficiency, and increase capacity, while managing NOx emissions. These benefits will translate into lower cost, more reliable gas transmission, and options for increasing deliverability from the existing infrastructure on high demand days. The power cylinders on large bore slow-speed integral engine/compressors do not in general combust equally. Variations in cylinder pressure between power cylinders occur cycle-to-cycle. These variations affect both individual cylinder performance and unit average performance. The magnitude of the variations in power cylinder combustion is dependent on a variety of parameters, including air/fuel ratio. Large variations in cylinder performance and peak firing pressure can lead to detonation and misfires, both of which can be damaging to the unit. Reducing the variation in combustion pressure, and moving the high and low performing cylinders closer to the mean is the goal of engine balancing. The benefit of improving the state of the engine ''balance'' is a small reduction in heat rate and a significant reduction in both crankshaft strain and emissions. A new method invented during the course of this project is combustion pressure ratio (CPR) balancing. This method is more effective than current methods because it naturally accounts for differences in compression pressure, which results from cylinder-to-cylinder differences in the amount of air flowing through the inlet ports and trapped at port closure. It also helps avoid compensation for low compression pressure by the

  14. Pythagoras's theorem on a two-dimensional lattice from a `natural' Dirac operator and Connes's distance formula

    Science.gov (United States)

    Dai, Jian; Song, Xing-Chang

    2001-07-01

    One of the key ingredients of Connes's noncommutative geometry is a generalized Dirac operator which induces a metric (Connes's distance) on the pure state space. We generalize such a Dirac operator devised by Dimakis et al, whose Connes distance recovers the linear distance on an one-dimensional lattice, to the two-dimensional case. This Dirac operator has the local eigenvalue property and induces a Euclidean distance on this two-dimensional lattice, which is referred to as `natural'. This kind of Dirac operator can be easily generalized into any higher-dimensional lattices.

  15. Pythagoras' Theorem on a 2D-Lattice from a "Natural" Dirac Operator and Connes' Distance Formula

    CERN Document Server

    Dai, J; Dai, Jian; Song, Xing-Chang

    2001-01-01

    One of the key ingredients of A. Connes' noncommutative geometry is a generalized Dirac operator which induces a metric(Connes' distance) on the state space. We generalize such a Dirac operator devised by A. Dimakis et al, whose Connes' distance recovers the linear distance on a 1D lattice, into 2D lattice. This Dirac operator being "naturally" defined has the so-called "local eigenvalue property" and induces Euclidean distance on this 2D lattice. This kind of Dirac operator can be generalized into any higher dimensional lattices.

  16. Wintertime Air Quality Impacts from Oil and Natural Gas Drilling Operations in the Bakken Formation Region

    Science.gov (United States)

    Evanoski-Cole, Ashley; Sive, Barkley; Zhou, Yong; Prenni, Anthony; Schurman, Misha; Day, Derek; Sullivan, Amy; Li, Yi; Hand, Jenny; Gebhart, Kristi; Schichtel, Bret; Collett, Jeffrey

    2016-04-01

    Oil and natural gas extraction has dramatically increased in the last decade in the United States due to the increased use of unconventional drilling techniques which include horizontal drilling and hydraulic fracturing. The impact of these drilling activities on local and regional air quality in oil and gas basins across the country are still relatively unknown, especially in recently developed basins such as the Bakken shale formation. This study is the first to conduct a comprehensive characterization of the regional air quality in the Bakken region. The Bakken shale formation, part of the Williston basin, is located in North Dakota and Montana in the United States and Saskatchewan and Manitoba in Canada. Oil and gas drilling operations can impact air quality in a variety of ways, including the generation of atmospheric particulate matter (PM), hazardous air pollutants, ozone, and greenhouse gas emissions. During the winter especially, PM formation can be enhanced and meteorological conditions can favor increased concentrations of PM and other pollutants. In this study, ground-based measurements throughout the Bakken region in North Dakota and Montana were collected over two consecutive winters to gain regional trends of air quality impacts from the oil and gas drilling activities. Additionally, one field site had a comprehensive suite of instrumentation operating at high time resolution to gain detailed characterization of the atmospheric composition. Measurements included organic carbon and black carbon concentrations in PM, the characterization of inorganic PM, inorganic gases, volatile organic compounds (VOCs), precipitation and meteorology. These elevated PM episodes were further investigated using the local meteorological conditions and regional transport patterns. Episodes of elevated concentrations of nitrogen oxides and sulfur dioxide were also detected. The VOC concentrations were analyzed and specific VOCs that are known oil and gas tracers were used

  17. Global Environmental Micro Sensors Test Operations in the Natural Environment (GEMSTONE

    Directory of Open Access Journals (Sweden)

    Mark ADAMS

    2007-10-01

    Full Text Available ENSCO, Inc. is developing an innovative atmospheric observing system known as Global Environmental Micro Sensors (GEMS. The GEMS concept features an integrated system of miniaturized in situ, airborne probes measuring temperature, relative humidity, pressure, and vector wind velocity. In order for the probes to remain airborne for long periods of time, their design is based on a helium-filled super-pressure balloon. The GEMS probes are neutrally buoyant and carried passively by the wind at predetermined levels. Each probe contains on-board satellite communication, power generation, processing, and geolocation capabilities. ENSCO has partnered with the National Aeronautics and Space Administration’s Kennedy Space Center (KSC Weather Office for a project called GEMS Test Operations in the Natural Environment (GEMSTONE. The goal of the GEMSTONE project was to build and field-test a small system of prototype probes in the Earth’s atmosphere. This paper summarizes the 9-month GEMSTONE project (Sep 2006 – May 2007 including probe and system engineering as well as experiment design and data analysis from laboratory and field tests. These tests revealed issues with reliability, sensor accuracy, electronics miniaturization, and sub-system optimization. Nevertheless, the success of the third and final free flight test provides a solid foundation to move forward in follow on projects addressing these issues as highlighted in the technology roadmap for future GEMS development.

  18. PDCA循环管理在手术室护理带教中的应用%Application of PDCA Circulation Management in Nursing Teaching in Operation Room

    Institute of Scientific and Technical Information of China (English)

    袁蕾

    2016-01-01

    目的:探讨分析PDCA循环管理在手术室护理带教中的应用。方法选取我院2014年1月~2014年12月实习的72名护生为研究对象,根据不同管理方法分为对照组与观察组,各组36名。对照组给予常规管理,观察组给予PDCA循环管理,对两组护生的带教成果进行观察对比。结果观察组护生的理论成绩、实践成绩、带教满意度均高于对照组,差异具有统计学意义(P<0.05)。结论在手术室护理带教中施行PDCA循环管理,可提高护生的综合成绩与满意度。%Objective To explore the application of PDCA circulation management in nursing teaching in operation room.Methods72 nursing students in our hospital from January 2014 to December 2014 were selected and divided into two groups according to different management methods, namely, the control group and the observation group, 36 students in each group. The control group was given routine management, the observation group was given PDCA cycle management, and the two groups of nursing students were observed and compared with the results of teaching.Results Nursing students' theory, practice and teaching satisfaction in the observation group were higher than the control group, the difference between the two groups was significant (P<0.05).Conclusion The implementation of PDCA cycle management in nursing teaching in operation room can signiifcantly improve the comprehensive performance and satisfaction of nursing students.

  19. Integrated treatment process using a natural Wyoming clinoptilolite for remediating produced waters from coalbed natural gas operations

    Science.gov (United States)

    Zhao, H.; Vance, G.F.; Urynowicz, M.A.; Gregory, R.W.

    2009-01-01

    Coalbed natural gas (CBNG) development in western U.S. states has resulted in an increase in an essential energy resource, but has also resulted in environmental impacts and additional regulatory needs. A concern associated with CBNG development relates to the production of the copious quantities of potentially saline-sodic groundwater required to recover the natural gas, hereafter referred to as CBNG water. Management of CBNG water is a major environmental challenge because of its quantity and quality. In this study, a locally available Na-rich natural zeolite (clinoptilolite) from Wyoming (WY) was examined for its potential to treat CBNG water to remove Na+ and lower the sodium adsorption ratio (SAR, mmol1/2 L- 1/2). The zeolite material was Ca-modified before being used in column experiments. Column breakthrough studies indicated that a metric tonne (1000??kg) of Ca-WY-zeolite could be used to treat 60,000??L of CBNG water in order to lower SAR of the CBNG water from 30 to an acceptable level of 10??mmol1/2 L- 1/2. An integrated treatment process using Na-WY-zeolite for alternately treating hard water and CBNG water was also examined for its potential to treat problematic waters in the region. Based on the results of this study, use of WY-zeolite appears to be a cost-effective water treatment technology for maximizing the beneficial use of poor-quality CBNG water. Ongoing studies are evaluating water treatment techniques involving infiltration ponds lined with zeolite. ?? 2008 Elsevier B.V. All rights reserved.

  20. Management of extracorporeal circulation during totally thoracoscopic cardiac operation%全胸腔镜心脏手术中体外循环管理

    Institute of Scientific and Technical Information of China (English)

    张力; 罗智超; 钟执文; 彭东; 周成斌; 章晓华; 郭惠明; 庄建

    2015-01-01

    目的:总结全胸腔镜心脏手术体外循环( ECC)管理特点。方法2013年1月至2014年6月开展123例全胸腔镜心脏手术,其中男性41例,女性82例。经颈内静脉和股静脉插静脉引流管,使用负压辅助静脉引流( VAVD)技术。右侧股动脉插动脉灌注管,逆行灌注全身。 ECC过程中采用中低温(28~32℃),灌注流量为60~80 ml/(kg·min)。心肌保护采用经主动脉根部顺行灌注冷血心肌保护液的方法。结果 ECC平均时间为(117.2±41.8)min,平均主动脉阻断时间为(73.7±32.1) min。所有病例均在开放升主动脉后心脏自动复跳。术后平均呼吸机辅助时间(13.2±12.7) h,术后第一天平均胸液量(43.5±74.1)ml,没有明显神经系统并发症,平均ICU时间(34.6±32.7) h。结论全胸腔镜心脏手术经外周血管插管,逆行灌注,辅以VAVD技术可改善静脉引流,其体外循环管理和心肌保护方法与常规体外循环管理类似。%Objective To summarize the management of extracorporeal circulation ( ECC) during totally thoracoscopic cardiac oper⁃ation. Methods From January 2013 to June 2014, 123 patients ( 41 males and 82 females) underwent totally thoracoscopic cardiac operation. The venous cannulas were inserted into the internal jugular vein and femoral vein. The vacuum assisted venous drainage ( VAVD) technology was used for enhancing the venous drainage. The arterial cannula was inserted to the right femoral artery for retro⁃grade perfusion. The flow of ECC was about 60-80 ml/(kg·min) under moderate hypothermia (28-32℃).Antegradecold blood car⁃dioplegia was delivered via the arotic root.Results The average ECC duration was 117.2±41.8 min and the average aortic cross-clamp time was 73.7±32.1 min. All patients restored heartrhythm spontaneously after release of cross-clamp. The post-operative ventilation time was 13.2±12.7 h and the average

  1. 研究堆自然循环阀直径的选择与实验验证%Selection of Natural Circulation Valve Diameter and Experiment Verification for Research Reactor

    Institute of Scientific and Technical Information of China (English)

    黄洪文; 刘汉刚; 徐显启; 钱达志

    2012-01-01

    为了确定某研究堆自然循环阀门直径,利用RETRAN-02分析模型,从自然循环阀(NCV)误打开和停堆后自然循环建立过程的角度,分析研究堆自然循环阀直径分别为150、200、250和300 mm时通过的流量、堆芯热通道的流量、燃料元件热点温度和最小偏离泡核沸腾比(MDNBR)的差异以及对反应堆安全的影响,最后选定NCV的直径为200 mm.%Based on different natural circulation valve diameters of 150mm, 200mm, 250mm and 300mm. RETRAN-02 code is used to calculate the flow of the natural circulation valve (NCV) and the hot channel, the temperature of the hot spot, the minimum departure from nuclear boiling ratio (MDNBR), and to analyze the safety of thermo-hydraulic parameter from the two aspects of NCV abnormal open and the establishment of natural circulation. It is proved that the NCV diameter of 200 mm is suitable.

  2. TECHNOLOGIES TO ENHANCE THE OPERATION OF EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn; Ford A. Phillips; Danny M. Deffenbaugh

    2006-05-31

    This project has documented and demonstrated the feasibility of technologies and operational choices for companies who operate the large installed fleet of integral engine compressors in pipeline service. Continued operations of this fleet is required to meet the projected growth of the U.S. gas market. Applying project results will meet the goals of the DOE-NETL Natural Gas Infrastructure program to enhance integrity, extend life, improve efficiency, and increase capacity, while managing NOx emissions. These benefits will translate into lower cost, more reliable gas transmission, and options for increasing deliverability from the existing infrastructure on high demand days. The power cylinders on large bore slow-speed integral engine/compressors do not in general combust equally. Variations in cylinder pressure between power cylinders occur cycle-to-cycle. These variations affect both individual cylinder performance and unit average performance. The magnitude of the variations in power cylinder combustion is dependent on a variety of parameters, including air/fuel ratio. Large variations in cylinder performance and peak firing pressure can lead to detonation and misfires, both of which can be damaging to the unit. Reducing the variation in combustion pressure, and moving the high and low performing cylinders closer to the mean is the goal of engine balancing. The benefit of improving the state of the engine ''balance'' is a small reduction in heat rate and a significant reduction in both crankshaft strain and emissions. A new method invented during the course of this project is combustion pressure ratio (CPR) balancing. This method is more effective than current methods because it naturally accounts for differences in compression pressure, which results from cylinder-to-cylinder differences in the amount of air flowing through the inlet ports and trapped at port closure. It also helps avoid compensation for low compression pressure by the

  3. Regional energy markets and the cost of natural flow dam operation

    Energy Technology Data Exchange (ETDEWEB)

    Sparrow, F.T.; Preckel, P.V.; Gotham, D.J. [Purdue University, Energy Center at Discovery Park, West Lafayette, IN (United States); Bowen, B.H. [American University in Kosovo, Pristina (RS); Yu, Z. [EmberClear, Inc., Houston, TX (United States)

    2011-11-15

    With the proliferation of electricity markets for the purchase and sale of firm and non-firm power and capacity, the possibility exists for using trade in these commodities to minimize the cost impact of operating dams to restore downstream flows to pre-dam patterns - so called Run of River (ROR) dam operation. We examine the impact of such markets on the incremental costs of ROR operation relative to least cost operation via a stochastic, dynamic optimization model. We identify features of the dam structure and of the economic environment that are critical to achieving ROR operation at modest incremental cost. (orig.)

  4. Intelligent system for control and automation of natural gas distribution operation; Sistema inteligente de controle e automacao da operacao de distribuicao de gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Scucuglia, Jose W.; Souza, Celso C. [Universidade para o Desenvolvimento do Estado e da Regiao do Pantanal (UNIDERP), Campo Grande, MS (Brazil). Curso de Engenharia Eletrica; Patricio, Cristian M.M.M.; Cruz, Lauro C.; Reis, Antonio M.; Cortez, Marco A.A.; Maldonado, Waldemar; Rosa, Willian A. [Universidade para o Desenvolvimento do Estado e da Regiao do Pantanal (UNIDERP), Campo Grande, MS (Brazil). Nucleo de Energia, Automacao e Controle; Teixeira, Marcelo C.M. [UNESP, Ilha Solteira, SP (Brazil). Faculdade de Engenharia Eletrica; Carrasco, Benjamim [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    The present work has as objective to present the development of a dedicated intelligent system to the operation of natural gas distribution. The system adds tools of project, simulation, supervision and control of the flow of natural gas in networks distribution, and is composed of hardware and intelligent software. The developed software possess friendly graphical interface, so that the operator composing visually the distribution network automatically, composes a mathematical model formed by a set of differential equations, being solved by the Newton-Raphson method. This tool of simulation allows, in function of network topology, to get through simulation the conditions gas flow in each point of the loop flow. The micro controlled hardware for acquisition of the data in real time and control of valves was developed. The hardware possesses flexible communication (Radio Frequency, Ethernet and Optical Fiber), intelligence for decision taking and auto test of its proper functioning, so that guarantee security in the operations. An implanted neural system in software propitiates the control monitoring of the characteristics operation and conditions of leak with loss of load, identifying inclusive the place of this leak along of the duct. A system with national technology was gotten, of low cost and high added technological value. (author)

  5. Organization and operation of the Sixth International Symposium on the Natural Radiation Environment (NRE VI)

    Energy Technology Data Exchange (ETDEWEB)

    Hopke, P.K.

    1996-10-01

    An important source of human exposure to radiation is the natural world including cosmic rays, cosmogenic radionuclides, natural terrestrial radionuclides, and radon isotopes and its decay products. Considerable effort is being expended on a worldwide basis to characterize the exposure to the natural radiation environment and determine the important pathways for the exposure to result in the dose to tissue that leads to injury and disease. The problem of background exposure to naturally occurring radioactivity has been the subject of research since the initial discovery of the radioactivity of uranium and thorium. However, with the advent of artificial sources of radiation with both benefits and harm the nature and magnitude of the natural radiation environment and the effects on various populations are important in the development of overall public health strategies as ALARA principles are applied to the situation.

  6. 78 FR 70163 - Communication of Operational Information between Natural Gas Pipelines and Electric Transmission...

    Science.gov (United States)

    2013-11-22

    .... Commission Determination 123. IV. Clarification Regarding Table-Top Exercises 126. A. NOPR 126. B. Comments... rule to help promote the reliability and efficiency of the natural gas and electric systems by....\\11\\ In contrast, due to the physical characteristics of interstate natural gas pipelines, the...

  7. TROPICAL METEOROLOGY & Climate: Hadley Circulation

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jian; Vecchi, Gabriel A.

    2015-01-30

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

  8. Theoretical investigations on operational performance of one- and two-shaft gas turbines used in circulating pressure fluidised bed firing; Theoretische Untersuchungen zum Betriebsverhalten von ein- und zweiwelligen Gasturbinen beim Einsatz in der zirkulierenden Druckwirbelschichtfeuerung

    Energy Technology Data Exchange (ETDEWEB)

    Nemet, A.; Fett, F.N. [Siegen Univ. (Gesamthochschule) (Germany). Inst. fuer Energietechnik

    1999-12-01

    By means of simulation calculations the stationary and instationary operating performance of two gas turbine connections with one and two shafts and their interaction with circulating pressure fluidised bed firing has been investigated in the present paper. It could be shown that the construction type and properties of the gas turbine considerably influences the partial load and transition performance of a circulating pressure fluidised bed firing plant. The properties of the gas turbine have a strong influence on the gas/solid flow in the circulating pressure fluidised bed. The investigated gas turbine with one shaft is limited in its adaptability to the demands of the circulating pressure fluidised bed below the LS-point, however it shows a good operating performance in all partial load ranges. The two-shaft gas turbine shows better adaptability and flexibility, however the potential of the circulating pressure fluidised bed firing generating an almost constant smoke gas temperature in partial load operation can not be fully utilised in the lower partial load range (< 50%) because the operating point of the high pressure compressor moves towards the pump limit with decreasing load. (orig.) [Deutsch] Anhand von Simulationsrechnungen wurde in dem vorliegenden Beitrag das stationaere und instationaere Betriebsverhalten zweier Gasturbinenschaltungen in ein- und zweiwelliger Bauart und ihr Zusammenspiel mit einer zirkulierenden Druckwirbelschichtfeuerung untersucht. Es konnte gezeigt werden, dass die Gasturbinenbauart und -charakteristik in erheblichem Masse das Teillast- und Uebergangsverhalten einer ZDWSF-Anlage mitbestimmt. Insbesondere hat die Gasturbinencharakteristik einen wesentlichen Einfluss auf die Gas/Feststoff-Stroemung in zirkulierenden Druckwirbelschichtfeuerungen. Die untersuchte Gasturbine in einwelliger Bauart ist unterhalb des LS-Eckpunkts in ihrer Anpassungsfaehigkeit an die Anforderungen der zirkulierenden Druckwirbelschicht zwar eingeschraenkt

  9. Open Feedlots Listed in the Iowa Department of Natural Resources Animal Feeding Operations Database

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Currently, the Animal Feeding Operations (AFO) database does not allow facilities to be queried by watershed, therefore, this coverage was developed to assist with...

  10. Percutaneous internal jugular venous cannulation for extracorporeal circulation during minimally invasive technique in children with congenital heart disease: operative technique and results.

    Science.gov (United States)

    Vida, Vladimiro L; Tiberio, Ivo; Gallo, Michele; Guariento, Alvise; Suti, Emirjeta; Pittarello, Demetrio; Stellin, Giovanni

    2016-10-01

    The aim of this study was to evaluate the safety and efficacy of the percutaneous cannulation of the internal jugular venous (PCIJV) for extracorporeal circulation during minimally invasive cardiac surgery (MICS) in children with simple congenital heart disease. From September 2007, 83 children (<16 years) underwent PCIJV for extracorporeal circulation. Primary outcome of the study was to evaluate the safety and advantages of PCIJV technique. Technical steps and pitfalls of PCIJV technique are described. Median age at surgery was 9 years (range 3.5-16 years) and median body weight was 31 kilograms (range 13-72 kilograms); 32 patients (40%) had a body weight less than 30 kilograms. The PCIJV was achieved with a 14 French cannula in 61 pts (73%), with a 17 Fr cannula in 22 (23%). The PIJVC was judged difficult in 2 patients (2.4%); in both of them cannulation was achieved at a different venous site There were no procedure-related complications and no flow disturbances during the extracorporeal circulation. The PCIJV during MICS is an effective and reproducible technique for achieving peripheral CPB in children with simple CHDs. We progressively expanded the use of this technique in smaller children and this allows us to further minimize surgical trauma without experiencing venous drainage's problems.

  11. Task 23 - background report on subsurface environmental issues relating to natural gas sweetening and dehydration operations. Topical report, February 1, 1994--February 28, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, J.A.

    1998-12-31

    This report describes information pertaining to environmental issues, toxicity, environmental transport, and fate of alkanolamines and glycols associated with natural gas sweetening and dehydration operations. Waste management associated with the operations is also discussed.

  12. 重水堆停堆工况下单相自然循环流动与传热分析%Analysis on Flow Rate and Heat Transfer of Single-phase Natural Circulation Under Shutdown Condition for PHWR

    Institute of Scientific and Technical Information of China (English)

    苑景田; 佟立丽; 曹学武

    2014-01-01

    The single-phase natural circulation of the main heat transport system (HTS) for CANDU 6 under shutdown condition was analyzed by using RELAP5 code ,and the single-phase natural circulation mass flow rate model was developed .The comparison analysis of the Vijayan model and natural circulation models including the Chrichill-Chu model and McAdams model for RELAP5 was conducted ,respectively .The results show that a lower horizontal heat transfer coefficient is obtained by using Vijayan model than that by the McAdams model ,causing a slight higher cladding temperature .However , the vertical heat transfer coefficients from both models have no significant difference .%使用RELAP5程序建立CANDU 6型重水堆模型,对停堆工况下主热传输系统环路内的单相自然循环进行了分析研究,并推导出重水堆单相自然循环流量模型。对 Vijayan模型与 RELAP5程序的自然对流传热模型(Churchill-Chu和McAdams模型)进行比较计算,结果表明,Vijayan模型计算的水平壁面传热系数低于程序模型,造成包壳温度略高,而竖直壁面传热系数则无明显差别。

  13. Sensitivity of natural gas HCCI combustion to fuel and operating parameters using detailed kinetic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S; Dibble, R; Flowers, D; Smith, J R; Westbrook, C K

    1999-07-19

    This paper uses the HCT (Hydrodynamics, Chemistry and Transport) chemical kinetics code to analyze natural gas HCCI combustion in an engine. The HCT code has been modified to better represent the conditions existing inside an engine, including a wall heat transfer correlation. Combustion control and low power output per displacement remain as two of the biggest challenges to obtaining satisfactory performance out of an HCCI engine, and these are addressed in this paper. The paper considers the effect of natural gas composition on HCCI combustion, and then explores three control strategies for HCCI engines: DME (dimethyl ether) addition, intake heating and hot EGR addition. The results show that HCCI combustion is sensitive to natural gas composition, and an active control may be required to compensate for possible changes in composition. The three control strategies being considered have a significant effect in changing the combustion parameters for the engine, and should be able to control HCCI combustion.

  14. Prevalence of Allergy to Natural Rubber Latex and Potential Cross Reacting Food in Operation Room Staff in Shiraz Hospitals -2006

    Directory of Open Access Journals (Sweden)

    H Nabavizade

    2007-07-01

    Full Text Available Introduction & Objective: Allergic reactions to natural rubber latex have increased during past 10 years especially among health care workers and patients with high exposure to latex allergens. Allergic reaction to latex is related to many diseases like occupational asthma. This study was performed to determine the prevalence of allergy to natural rubber latex and potential cross reacting food in operation room staff in Shiraz hospitals. Materials & Methods: In this cross-sectional descriptive study five hundred eighty operation room staff of ten private and state hospitals in Shiraz completed latex allergy questionnaire. They were questioned about personal history and previous history of latex sensitivity, symptoms of latex reactivity and about other allergies particularly to foods that may cross react with latex. Informed consent was obtained and skin prick testing was performed with natural rubber latex. Skin prick tests were done with three potentially cross reacting food (banana, Kiwi, and potato. The obtained data were analyzed with SPSS software and Chi-square test. Results: Among the 580 operation room workers 104 (17.9 % of participants were positive to latex skin test. We found a significant association between positive skin test to latex in operation room staff and atopy, urticaria and food allergy. Positive skin test to latex related to positive kiwi skin test (p<0.05. The prevalence did not vary by sex, age, education, surgical and non surgical glove users, history of contact dermatitis or smoking status. Conclusion: Latex allergy has a high prevalence in personnel of operation room. Evaluation of present symptom and prediction of future disease necessitate screening test in individuals at risk.

  15. An integrated transient model for simulating the operation of natural gas transport systems

    NARCIS (Netherlands)

    Pambour, Kwabena Addo; Bolado-Lavin, Ricardo; Dijkema, Gerard P. J.

    This paper presents an integrated transient hydraulic model that describes the dynamic behavior of natural gas transport systems (GTS). The model includes sub models of the most important facilities comprising a GTS, such as pipelines, compressor stations, pressure reduction stations, underground

  16. Study of the dosimetric and operating characteristics of natural diamond detectors

    Energy Technology Data Exchange (ETDEWEB)

    De Angelis, C.; Onori, S.; Pacilio, M. [Istituto Superiore di Sanita' , Roma (Italy); INFN, Gruppo Collegato Sanita' , Roma (Italy); Cirrone, P.; Cuttone, G.; Raffaele, L.; Sabini, M.G. [INFN-LNS, Catania (Italy); Bucciolini, M.; Mazzocchi, S. [Firenze Univ., Firenze (Italy). Dipartimento di Fisiopatologia Clinica; INFN, Florence (Italy)

    2002-07-01

    Main properties of PTW natural diamond detectors have been studied in photon, electron and photon beams. Suitability for depth dose and dose profile measurements in photon beams has been investigated. The necessity to characterise each detector sample before its clinical use has been addressed.

  17. 78 FR 44900 - Communication of Operational Information Between Natural Gas Pipelines and Electric Transmission...

    Science.gov (United States)

    2013-07-25

    ... should not be shared with natural gas pipeline representatives or affiliates that sell or buy wholesale...'' depends on the specific facts of the behavior and the circumstances to determine whether disparities exist....C. Cir. 2010) (citing Ark. Elec. Energy Consumers v. FERC, 290 F.3d 362, 367 (D.C. Cir. 2002)...

  18. An integrated transient model for simulating the operation of natural gas transport systems

    NARCIS (Netherlands)

    Pambour, Kwabena Addo; Bolado-Lavin, Ricardo; Dijkema, Gerard P. J.

    2016-01-01

    This paper presents an integrated transient hydraulic model that describes the dynamic behavior of natural gas transport systems (GTS). The model includes sub models of the most important facilities comprising a GTS, such as pipelines, compressor stations, pressure reduction stations, underground ga

  19. An integrated transient model for simulating the operation of natural gas transport systems

    NARCIS (Netherlands)

    Pambour, Kwabena Addo; Bolado-Lavin, Ricardo; Dijkema, Gerard P. J.

    2016-01-01

    This paper presents an integrated transient hydraulic model that describes the dynamic behavior of natural gas transport systems (GTS). The model includes sub models of the most important facilities comprising a GTS, such as pipelines, compressor stations, pressure reduction stations, underground ga

  20. 76 FR 37309 - Parts and Accessories Necessary for Safe Operation; Application for Exemption From the Natural...

    Science.gov (United States)

    2011-06-27

    ... with natural gas fuel systems. NHTSA's Federal Motor Vehicle Safety Standard (FMVSS) No. 303, ``Fuel... to ``meet all applicable Federal Motor Vehicle Safety Standards, as defined by the National Highway... vehicle. It is believed the intent of the existing regulation is to avoid the risk of fuel entering the...

  1. Record of Cycling Operation of the Natural Nuclear Reactor in the Oklo/Okelobondo Area in Gabon

    Science.gov (United States)

    Meshik, A. P.; Hohenberg, C. M.; Pravdivtseva, O. V.

    2004-10-01

    Using selective laser extraction technique combined with sensitive ion-counting mass spectrometry, we have analyzed the isotopic structure of fission noble gases in U-free La-Ce-Sr-Ca aluminous hydroxy phosphate associated with the 2 billion yr old Oklo natural nuclear reactor. In addition to elevated abundances of fission-produced Zr, Ce, and Sr, we discovered high (up to 0.03 cm3 STP/g) concentrations of fission Xe and Kr, the largest ever observed in any natural material. The specific isotopic structure of xenon in this mineral defines a cycling operation for the reactor with 30-min active pulses separated by 2.5h dormant periods. Thus, nature not only created conditions for self-sustained nuclear chain reactions, but also provided clues on how to retain nuclear wastes, including fission Xe and Kr, and prevent uncontrolled runaway chain reaction.

  2. The nature and necessity of operational flexibility in the emergency department.

    Science.gov (United States)

    Ward, Michael J; Ferrand, Yann B; Laker, Lauren F; Froehle, Craig M; Vogus, Timothy J; Dittus, Robert S; Kripalani, Sunil; Pines, Jesse M

    2015-02-01

    Hospital-based emergency departments (EDs), given their high cost and major role in allocating care resources, are at the center of the debate about how to maximize value in delivering health care in the United States. To operate effectively and create value, EDs must be flexible, having the ability to rapidly adapt to the highly variable needs of patients. The concept of flexibility has not been well described in the ED literature. We introduce the concept, outline its potential benefits, and provide some illustrative examples to facilitate incorporating flexibility into ED management. We draw on operations research and organizational theory to identify and describe 5 forms of flexibility: physical, human resource, volume, behavioral, and conceptual. Each form of flexibility may be useful individually or in combination with other forms in improving ED performance and enhancing value. We also offer suggestions for measuring operational flexibility in the ED. A better understanding of operational flexibility and its application to the ED may help us move away from reactive approaches of managing variable demand to a more systematic approach. We also address the tension between cost and flexibility and outline how "partial flexibility" may help resolve some challenges. Applying concepts of flexibility from other disciplines may help clinicians and administrators think differently about their workflow and provide new insights into managing issues of cost, flow, and quality in the ED. Copyright © 2014 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

  3. The complex of looped diagrams and natural operations on Hochschild homology

    DEFF Research Database (Denmark)

    Klamt, Angela

    operations for commutative algebras (as computed in the rst part of the thesis) and a shifted BV structure which has been investigated by Abbaspour earlier. We prove that this BV structure comes from a suspended Cacti operad sitting inside the complex of looped diagrams. Last, we eneralize the setup...

  4. THE DEVELOPMENT AND NATURE OF OPERATIONS RESEARCH AND ITS RELEVANCE TO EDUCATIONAL-MEDIA RESEARCH.

    Science.gov (United States)

    ACKOFF, RUSSELL

    SUCH QUESTIONS AS WHY AND HOW OPERATIONS RESEARCH (OR) AND SYSTEMS ANALYSIS ORIGINATED, WHAT THEY ARE, AND WHAT CONTRIBUTIONS THEY MIGHT MAKE TO INSTRUCTIONAL MEDIA PROGRAMS ARE ANSWERED. "OR" ORIGINATED AT THE OUTBREAK OF WORLD WAR II WHEN MILITARY ORGANIZATIONS, WHICH HAD BEEN DEVELOPING THEIR TECHNOLOGY FASTER THAN IT COULD BE…

  5. The Natural History of Clinical Operational Tolerance After Kidney Transplantation Through Twenty-Seven Cases

    NARCIS (Netherlands)

    Brouard, S.; Pallier, A.; Renaudin, K.; Foucher, Y.; Danger, R.; Devys, A.; Cesbron, A.; Guillot-Guegen, C.; Ashton-Chess, J.; Roux, S. le; Harb, J.; Roussey, G.; Subra, J.F.; Villemain, F.; Legendre, C.; Bemelman, F.J.; Orlando, G.; Garnier, A.; Jambon, H.; Monies De Sagazan, H. le; Braun, L.; Noel, C.; Pillebout, E.; Moal, M.C.; Cantarell, C.; Hoitsma, A.J.; Ranbant, M.; Testa, A.; Soulillou, J.P.; Giral, M.

    2012-01-01

    We report here on a European cohort of 27 kidney transplant recipients displaying operational tolerance, compared to two cohorts of matched kidney transplant recipients under immunosuppression and patients who stopped immunosuppressive drugs and presented with rejection. We report that a lower propo

  6. Natural vibration response based damage detection for an operating wind turbine via Random Coefficient Linear Parameter Varying AR modelling

    Science.gov (United States)

    Avendaño-Valencia, L. D.; Fassois, S. D.

    2015-07-01

    The problem of damage detection in an operating wind turbine under normal operating conditions is addressed. This is characterized by difficulties associated with the lack of measurable excitation(s), the vibration response non-stationary nature, and its dependence on various types of uncertainties. To overcome these difficulties a stochastic approach based on Random Coefficient (RC) Linear Parameter Varying (LPV) AutoRegressive (AR) models is postulated. These models may effectively represent the non-stationary random vibration response under healthy conditions and subsequently used for damage detection through hypothesis testing. The performance of the method for damage and fault detection in an operating wind turbine is subsequently assessed via Monte Carlo simulations using the FAST simulation package.

  7. BRIDGING THE STRATEGIC TO OPERATIONAL GAP: AIR MOBILTY IN NATURAL DISASTER RELIEF

    Science.gov (United States)

    2016-06-01

    the picture at the beginning of this chapter. Note that there are zero USAF air mobility aircraft on the apron, but rather all international and...airport to the tsunami’s ground zero . The Japanese government and military were able to provide extensive search and rescue, as well as relief...for natural disasters. They have extensive knowledge and experience in prepping for and responding to contingencies. In the case of the Great

  8. Year of Expanding into Circulating Biomarkers

    Directory of Open Access Journals (Sweden)

    Shidong Jia

    2015-01-01

    Full Text Available This editorial article summarizes the achievements and current challenges for the Journal of Circulating Biomarkers (JCB regarding a more strategic approach to branding and attracting a high quality variety of articles. More emphasis is placed on fostering engagement with academic and industry sources operating at the cutting-edge of translational technologies applied to the field of circulating biomarkers (interface between extracellular vesicles including exosomes and microvesicles, circulating tumour cells, cell-free circulating DNA and circulating protein markers and with those in the investment arena seeking and providing private funding for this area of research.

  9. Year of Expanding into Circulating Biomarkers

    Directory of Open Access Journals (Sweden)

    Shidong Jia

    2015-01-01

    Full Text Available This editorial article summarizes the achievements and current challenges for the Journal of Circulating Biomarkers (JCB regarding a more strategic approach to branding and attracting a high quality variety of articles. More emphasis is placed on fostering engagement with academic and industry sources operating at the cutting-edge of transla‐ tional technologies applied to the field of circulating biomarkers (interface between extracellular vesicles including exosomes and microvesicles, circulating tumour cells, cell-free circulating DNA and circulating protein markers and with those in the investment arena seeking and providing private funding for this area of research.

  10. Year of Expanding into Circulating Biomarkers.

    Science.gov (United States)

    Jia, Shidong; Kuo, Winston Patrick

    2015-01-01

    This editorial article summarizes the achievements and current challenges for the Journal of Circulating Biomarkers (JCB) regarding a more strategic approach to branding and attracting a high quality variety of articles. More emphasis is placed on fostering engagement with academic and industry sources operating at the cutting-edge of translational technologies applied to the field of circulating biomarkers (interface between extracellular vesicles including exosomes and microvesicles, circulating tumour cells, cell-free circulating DNA and circulating protein markers) and with those in the investment arena seeking and providing private funding for this area of research.

  11. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  12. Impact of Remotely Piloted Aircraft Type on Operations Using the Same Control Station: A Natural Experiment

    Science.gov (United States)

    2013-07-01

    give rise to them (3). This theoretical framework has been popularized in Reason’s “Swiss Cheese ” model of human error, which was later expanded...management 32 46.4 7 36.8 0.459 Organizational culture 8 11.6 5 26.3 0.109 Organizational process 42 60.9 8 42.1 0.144 Logistic...Perceptual factors 0.742 Technological environment 0.660 2 19.50 Organizational culture 0.834 Planned inappropriate operations 0.727 Resource

  13. Influence of operation of national experimental nuclear reactor on the natural environment

    Directory of Open Access Journals (Sweden)

    Agnieszka Kaczmarek-Kacprzak

    2012-09-01

    Full Text Available This paper presents the impact of experimental nuclear reactor operations on the national environment, based on assessment reports of the radiological protection of active nuclear technology sources. Using the analysis of measurements carried out in the last 15 years, the trends are presented in selected elements of the environment on the Świerk Nuclear Centre site and its surroundings. In addition, the impact of research results is presented from the fi fteen year period of environmental analysis on building public confi dence on the eve of the start of construction of the first Polish nuclear power plant.

  14. Understanding physiological and degenerative natural vision mechanisms to define contrast and contour operators.

    Directory of Open Access Journals (Sweden)

    Jacques Demongeot

    Full Text Available BACKGROUND: Dynamical systems like neural networks based on lateral inhibition have a large field of applications in image processing, robotics and morphogenesis modeling. In this paper, we will propose some examples of dynamical flows used in image contrasting and contouring. METHODOLOGY: First we present the physiological basis of the retina function by showing the role of the lateral inhibition in the optical illusions and pathologic processes generation. Then, based on these biological considerations about the real vision mechanisms, we study an enhancement method for contrasting medical images, using either a discrete neural network approach, or its continuous version, i.e. a non-isotropic diffusion reaction partial differential system. Following this, we introduce other continuous operators based on similar biomimetic approaches: a chemotactic contrasting method, a viability contouring algorithm and an attentional focus operator. Then, we introduce the new notion of mixed potential Hamiltonian flows; we compare it with the watershed method and we use it for contouring. CONCLUSIONS: We conclude by showing the utility of these biomimetic methods with some examples of application in medical imaging and computed assisted surgery.

  15. Natural gas distribution operation and maintenance dissemination project Kaunas City, Lithuania. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    The main objective of this project has been to disseminate the results and experiences achieved during the former projects in Kaunas to other Lithuanian gas companies and the gas sector in general. Also new subjects selected in co-operation with Kaunas Gas Company, the Lithuanian Energy Institute and the Lithuanian Gas Training Centre, where improvements were required, have been implemented. The components of the project were the following: (1) A training course in cathodic protection. One course concerning measuring and registration and one course concerning design and implementation. (2) A pilot project to develop methods for measuring cathodic protection on coherent steel pipe network. (3) Analysis of gas losses related to types of gas meters and calibration of meters. (4) A training course and technology transfer concerning relations between gas companies and consumers. (5) Dissemination of the experience of 1998 from the preparation of an operation and maintenance manual for Kaunas Gas Company. Dissemination of the ideas to other Lithuanian gas companies. (EHS)

  16. 循环冷却水系统的日常运行与管理%Routine Operation and Management of Circulating Cool Water System

    Institute of Scientific and Technical Information of China (English)

    任玉兵

    2012-01-01

    加强循环水系统管理的目的是在保证循环冷却水温度、压力、流量的基础上,保持水质良好,防止设备腐蚀和结垢,提高设备的使用寿命和取得良好的经济效益.详细介绍了尿素装置循环冷却水系统的日常监控项目,对减少不良水质对设备的腐蚀因素进行分析并提出相应的减缓腐蚀的措施,对循环冷却水系统日常监测及巡检工作、黏泥剥离方案及特殊情况的处理提出相应的措施.%The aim of tightening up the management of the circulating cooling water system is on the basis of ensuring the temperature, pressure and flowrate of the circulating cooling water to maintain the water quality in a good condition, prevent the equipment from corrosion and scaling, lengthen the service life of the equipment, and reap good economic benefit. A detailed explanation is given of the routine monitoring items of the system in the urea unit, an analysis is made of a decrease in corrosion factors of the equipment by poor water quality, with relevant measures suggested for slowing down the corrosion rate, routine monitoring and rounds of inspection of the system, schemes for stripping slime and handling of exceptional cases.

  17. Natural Image Enhancement Using a Biogeography Based Optimization Enhanced with Blended Migration Operator

    Directory of Open Access Journals (Sweden)

    J. Jasper

    2014-01-01

    Full Text Available This paper addresses a novel and efficient algorithm for solving optimization problem in image processing applications. Image enhancement (IE is one of the complex optimization problems in image processing. The main goal of this paper is to enhance color images such that the eminence of the image is more suitable than the original image from the perceptual viewpoint of human. Traditional methods require prior knowledge of the image to be enhanced, whereas the aim of the proposed biogeography based optimization (BBO enhanced with blended migration operator (BMO algorithm is to maximize the objective function in order to enhance the image contrast by maximizing the parameters like edge intensity, edge information, and entropy. Experimental results are compared with the current state-of-the-art approaches and indicate the superiority of the proposed technique in terms of subjective and objective evaluation.

  18. Spring flood pH decline in northern Sweden: Towards an operational model separating natural acidity from anthropogenic acidification

    Energy Technology Data Exchange (ETDEWEB)

    Laudon, H.

    1999-10-01

    The spring flood is a defining feature of the ecosystem in northern Sweden. In this region, spring flood is an occasion for dramatic hydrochemical changes that profoundly effect the biodiversity of the aquatic ecosystem. Spring flood is also the period most susceptible to anthropogenic acidification. A belief in the anthropogenic component to pH decline during spring flood has been an important factor in spending over half a billion crowns to lime surface waters in Northern Sweden during the last decade. The natural component of episodic pH decline during spring flood, however, has received less attention. The main objective of this work is to present an operational model for separating and quantifying the anthropogenic and natural contributions of episodic acidification during high flow events in Northern Sweden. The key assumptions in this model are that baseflow ANC has not been affected by anthropogenic acidification, that DOC has not changed due to modern land-use practice and that natural dilution during hydrological episodes can be quantified. The limited data requirements of 10-15 stream water samples before and during spring flood make the model suitable for widespread use in environmental monitoring programs. This makes it possible to distinguish trends of human impact as well as natural pH decline in space and time. Modeling results from northern Sweden demonstrate that the natural driving mechanisms of dilution and organic acidity were the dominant factors in the episodic acidification of spring flood in the region. The anthropogenic contribution to spring pH decline was similar in size to the natural contribution in only two of the more than 30 events where this model was applied. Natural factors alone were found to cause pH values below 4.5 in some streams. Anthropogenic sources of acidity can be superimposed on this natural dynamics. In the sites studied, the magnitude of the anthropogenic ANC decline was correlated to the winter deposition of

  19. Research on Natural Gas Safe Operating Condition%天然气安全操作工况的研究

    Institute of Scientific and Technical Information of China (English)

    俞群援

    2016-01-01

    In view of natural gas’s characteristics of flammable and explosive, using nitrogen’s inerting principle, some researches on the explosion limit of natural gas and air mixture and the critical explosion suppression concentration of nitrogen are carried out on the basis of relative explosion testing experiments. Therefore, the theoretical basis can be provided for natural gas safe operation, then make the process of using natural gas safe and avoid accidents.%针对天然气易燃易爆的特性,利用氮气的惰化原理,以相关爆炸测试实验为基础研究天然气与空气混合气体的爆炸上下限、氮气的临界抑爆浓度,从而为天然气的安全运行操作提供理论依据,确保天然气使用操作过程的安全、避免事故的发生。

  20. TECHNOLOGIES TO ENHANCE THE OPERATION OF EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE - MANIFOLD DESIGN FOR CONTROLLING ENGINE AIR BALANCE

    Energy Technology Data Exchange (ETDEWEB)

    Gary D. Bourn; Ford A. Phillips; Ralph E. Harris

    2005-12-01

    This document provides results and conclusions for Task 15.0--Detailed Analysis of Air Balance & Conceptual Design of Improved Air Manifolds in the ''Technologies to Enhance the Operation of Existing Natural Gas Compression Infrastructure'' project. SwRI{reg_sign} is conducting this project for DOE in conjunction with Pipeline Research Council International, Gas Machinery Research Council, El Paso Pipeline, Cooper Compression, and Southern Star, under DOE contract number DE-FC26-02NT41646. The objective of Task 15.0 was to investigate the perceived imbalance in airflow between power cylinders in two-stroke integral compressor engines and develop solutions via manifold redesign. The overall project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity.

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

    Science.gov (United States)

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

    2015-03-01

    Infection with hepatitis B virus (HBV) can result in spontaneous resolution or chronic infection, which can remain asymptomatic or can progress to cirrhosis and/or hepatocellular carcinoma. The host immune response is thought to be a major determinant of the outcome of HBV infection and virus-specific cytotoxic T lymphocytes (CTL) can mediate immunity against the virus and cause liver pathology. Antigen-nonspecific innate lymphocytes may also contribute to HBV infection and liver disease, therefore, we examined the frequencies, phenotypes, cytolytic activities and cytokine profiles of circulating natural killer (NK) cells, CD1d-restricted invariant natural killer T (iNKT) cells and CD56(+) T cells in 102 asymptomatic HBV-infected patients and compared them with those in 66 uninfected control subjects. NK cells expressing low levels of CD56 (CD56(dim)) and CD56(+) T cells were significantly expanded in the circulation of HBV-infected patients compared with control subjects. CD1d expression and iNKT cell frequencies were similar in both groups. Despite these expansions, we did not detect augmented natural or cytokine-induced cytotoxicity in the HBV-infected subjects. All lymphocyte populations studied produced interferon-γ (IFN-γ) significantly more frequently when taken from HBV-infected patients compared with when taken from healthy controls. Additionally, NK cells from the patients more frequently produced interleukin-10. As our HBV-infected cohort consisted of asymptomatic patients with low viral loads, we propose that CD56(dim) NK cells and CD56(+) T cells control HBV infection by noncytolytic mechanisms. © 2014 John Wiley & Sons Ltd.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, L.L.

    1998-10-07

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

  3. Special considerations on operating a fuel cell power plant using natural gas with marginal heating value

    Energy Technology Data Exchange (ETDEWEB)

    Moses, L. Ng; Chien-Liang Lin [Industrial Technology Research Institute, Taiwan (China); Ya-Tang Cheng [Power Research Institute, Taiwan (China)

    1996-12-31

    In realizing new power generation technologies in Taiwan, a phosphoric acid fuel cell power plant (model PC2513, ONSI Corporation) has been installed in the premises of the Power Research Institute of the Taiwan Power Company in Taipei County of Taiwan. The pipeline gas supplying to the site of this power plant has a high percentage of carbon dioxide and thus a slightly lower heating value than that specified by the manufacturer. Because of the lowering of heating value of input gas, the highest Output power from the power plant is understandably less than the rated power of 200 kW designed. Further, the transient response of the power plant as interrupted from the Grid is also affected. Since this gas is also the pipeline gas supplying to the heavily populated Taipei Municipal area, it is conceivable that the success of the operations of fuel cells using this fuel is of vital importance to the promotion of the use of this power generation technology in Taiwan. Hence, experiments were set up to assess the feasibility of this fuel cell power plant using the existing pipeline gas in this part of Taiwan where fuel cells would most likely find useful.

  4. Operability Analysis of Sea Water Circulation Pump in AP 1000 PWR%AP1000核电站海水循环泵可运行性分析

    Institute of Scientific and Technical Information of China (English)

    欧鸣雄; 严建华; 盛绛; 施卫东; 滕国荣

    2014-01-01

    建立了A P1000立式循环泵机组的整机有限元模型,采用响应谱法针对循环泵在设计地震载荷工况下的强度及其动、静部件的变形位移进行了分析,并对该泵在设计地震载荷工况下的结构完整性和可运行性进行了评估。分析结果显示,该泵的1阶横向弯曲振动频率为14.4 Hz ,在单位水平激励载荷下,其前4阶振型在模型中的有效质量分数达0.94。在设计地震载荷工况下,作为主承压部件的泵体最大组合应力为203 M Pa ,叶轮室段壳体最大变形位移不超过1.5mm,转子部件最大组合应力为1.7MPa,最大变形位移为0.8mm,该系列响应值均在循环泵设计允许范围内,分析结果显示该泵能满足结构完整性和可运行性的要求。%The integrated definite element model of vertical circulation pump assembles in AP1000 was built .The static analysis and response spectrum analysis were used for normal design condition and design earthquake condition respectively , and the integrality and operability of pump were evaluated through strength and displacement analysis .The results demonstrate that the 1st lateral natural frequency of the pump is 14.4 Hz ,and the first 4 vibration mode shapes consist of an effective mass ratio of 0.94 in the model under a horizontal excitation load .At the design seismic load condition ,the max combination stress of pump case as the main pressure-bearing container is 203 M Pa ,the max displacement in impeller case is 1.5 mm ,the max combination stress of motor assemble is 1.7 M Pa ,and the max displacement of motor assemble is 0.8 mm , all these results are allowable in design . The analysis results demonstrate that the integrality and operability demands of pump are met in this design .

  5. Analysis of the possible incidence of ICMS (tax on circulation of merchandises and services) on burning natural gas; Analise da possivel incidencia de ICMS (Imposto sobre Circulacao de Mercadorias e Servicos) na queima de gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Marianna Perantoni; Silva, Fernando Henrique Dantas de Araujo [Agencia Nacional do Petroleo, Gas Natural e Biocombustiveis (ANP), Brasilia, DF (Brazil). Programa de Recursos Humanos em Direito do Petroleo, Gas Natural e Biocombustiveis

    2010-02-15

    This paper proposes to address the issue in regards to tax national gas industry, which, to date, has not their economic agents classified as 'Imposto sobre Circulacao de Mercadorias e Servicos, ICMS' (tax on circulation of merchandises and services) for the gas burned in flares. Despite this fact, within their needs and skills raised, the Treasury Department of the Sao Paulo and Rio de Janeiro States, announced that they will collect the tax mentioned in the aforementioned circumstances, causing a collision to generate the which have different legal arguments. The research will address arguments for and against the tax incidence of flaring, within legal parameters.

  6. Optogenetic mimicry of the transient activation of dopamine neurons by natural reward is sufficient for operant reinforcement.

    Directory of Open Access Journals (Sweden)

    Kyung Man Kim

    Full Text Available Activation of dopamine receptors in forebrain regions, for minutes or longer, is known to be sufficient for positive reinforcement of stimuli and actions. However, the firing rate of dopamine neurons is increased for only about 200 milliseconds following natural reward events that are better than expected, a response which has been described as a "reward prediction error" (RPE. Although RPE drives reinforcement learning (RL in computational models, it has not been possible to directly test whether the transient dopamine signal actually drives RL. Here we have performed optical stimulation of genetically targeted ventral tegmental area (VTA dopamine neurons expressing Channelrhodopsin-2 (ChR2 in mice. We mimicked the transient activation of dopamine neurons that occurs in response to natural reward by applying a light pulse of 200 ms in VTA. When a single light pulse followed each self-initiated nose poke, it was sufficient in itself to cause operant reinforcement. Furthermore, when optical stimulation was delivered in separate sessions according to a predetermined pattern, it increased locomotion and contralateral rotations, behaviors that are known to result from activation of dopamine neurons. All three of the optically induced operant and locomotor behaviors were tightly correlated with the number of VTA dopamine neurons that expressed ChR2, providing additional evidence that the behavioral responses were caused by activation of dopamine neurons. These results provide strong evidence that the transient activation of dopamine neurons provides a functional reward signal that drives learning, in support of RL theories of dopamine function.

  7. Xenon in oklo al phosphate: implication for operational conditions of natural reactors.

    Science.gov (United States)

    Meshik, A. P.; Hohenberg, C. M.; Pravdivtseva, O. V.

    2003-04-01

    New data for the Oklo natural reactor (Gabon), obtained by laser microprobe extraction and high precision noble gas mass-spectrometry, confirm our previous findings of large amount of anomalous Xe in U-free Al-phosphate adjacent to uraninite [1]. Compared with known fission spectra, the anomalous Xe is enriched in 132Xe, 131Xe and, to a less extent, 129Xe and 134Xe. It was suggested [1] that the observed Xe anomalies are due to chemical fractionation of Xe from β^ precursors (mainly I and Te) in isobaric decay chains. However, no mechanisms were proposed at that time. In this work, a follow-up to the previous studies, we explore the manner in which these anomalies may be produced. Apparently, under the temperatures present during the active periods of the Oklo reactor (300 - 450^oC), both I and Xe may easily diffuse out of U-oxides. Te in general is less mobile, due to slightly higher ionic radius, and has better retention than I and Xe. When the chain reaction is stopped, the temperature starts dropping and at the certain moment Xe formed from Te starts to retain in the Al-phosphate. Since that moment, accumulation of each Xe isotope must be proportional to decay time of corresponding Te isotope. This may in fact be responsible for the Xe anomalies found in Al-phosphate. 132Te, 131Te and 134Te have different half-lives and therefore ratios of these isotopes will not remain constant after the chain reaction is terminated due to the lack of water. Our calculation demonstrates that to produce the observed Xe anomalies the reactor must have been cycling with about 1frac{3}{4} hour period. Large concentration of fission products found in Al-phosphate also suggests that this material may be suitable for long-term storage of nuclear wastes. We are grateful to Don Bogard and to late Paul K. Kuroda with whom the idea of thermal cycling of Oklo reactor has been discussed. The Oklo sample was provided by Maurice Pagel and Yuri Dymkov. This work is supported by NASA grant

  8. Effect of NaCl/Hydroxyethyl Starch 200/0.5 on Lung Function and Hemodynamics in Patients Operated on under Extracorporeal Circulation

    Directory of Open Access Journals (Sweden)

    V. V. Lomivorotov

    2012-01-01

    Full Text Available Objective: to study the effect of 7.2% NaCl/hydroxyethyl starch 200/0.5 on extravascular lung water and respiratory and cardiovascular systems in patients with coronary heart disease (CHD after myocardial revascularization under extracorporeal circulation (EC. Subjects and methods. A prospective, randomized study was conducted in 40 patients with coronary artery disease. A study group (n=20 received 7.2% NaCl/hydroxyethyl starch 200/0.5; a control group (n=20 had 0.9% NaCl in a dose of 4 ml/kg within 30 min before EC. Extravascular lung water and central hemodynamic parameters were assessed using transpulmonary thermodilution and a Swan-Ganz catheter; respiratory function was estimated by the arterial oxygenation index, alveolar-arterial oxygen tension difference, and venous shunt fraction. Plasma osmolality and Na concentration were determined using an Osmomat 030 device. Conclusion. The intraoperative use of 7.2% NaCl/hydroxyethyl starch 200/0.5 in patients with CHD leads to a significant reduction in extravascular lung water after myocardial revascularization, thereby effectively protecting pulmonary oxygenizing function. The single administration of 7.2% NaCl/hydroxyethyl starch causes a short-term increase in cardiac index and it is a relatively safe in preventing neurological disorders and heart failure. Key words: 7.2% NaCl/hydroxyethyl starch 200/0.5; extravascular lung water, respiratory function, cardiac index, osmolarity.

  9. Dispensing with the DVD Circulation Dilemma

    Science.gov (United States)

    Ellis, Mark

    2008-01-01

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

  10. Operation Optimization of Constant-speed Circulating Water Pumps in a Thermal Power Plant under Full Conditions%火电机组定速循环水泵的全工况运行优化

    Institute of Scientific and Technical Information of China (English)

    刘吉臻; 王玮; 曾德良; 常太华; 柳玉

    2011-01-01

    为解决枚举法得出的定速循环水泵最优运行方式的局限性,通过分析汽轮机低压缸、冷却塔及凝汽器真空的全工况计算模型,提出了在环境温度相等的前提下进行循环水泵全工况运行优化,并对其流程进行了阐述,将排汽压力对汽轮机功率的修正曲线进行了全工况拟合,利用二分法求解机组各工况下循环水泵相邻运行方式的等效益点,进而获得等效益曲线,并采用二分法对某电厂的定速循环水泵进行了等效益曲线实例验证.结果表明:循环水泵优化运行后,平均可降低煤耗0.594g/(kw·h).%In order to overcome the limitation of optimized operation of constant-speed circulating water pumps obtained by enumeration method, the idea of optimizing the operation of circulating water pumps under full conditions was proposed on the premise of equal inlet temperature of cooling water, based on a- nalysis of full-condition calculation models for low-pressure cylinder, cooling tower and condenser vacuum. The specific optimization process is to fit the corrective curve between turbine power and exhaust pressure under full conditions, then to solve the equal efficiency points between adjacent operating modes of circu- lating water pumps by dichotomy method, and finally to acquire the equal efficiency curves. Verification results on the equal efficiency curves in a certain power plant show that an average of 0. 594 g/(kw .h) net coal consumption can be saved after the optimization of relevant circulating water pumps.

  11. A Novel Boil-Off Gas Re-Liquefaction Using a Spray Recondenser for Liquefied Natural-Gas Bunkering Operations

    Directory of Open Access Journals (Sweden)

    Jiheon Ryu

    2016-11-01

    Full Text Available This study presents the design of a novel boil-off gas (BOG re-liquefaction technology using a BOG recondenser system. The BOG recondenser system targets the liquefied natural gas (LNG bunkering operation, in which the BOG phase transition occurs in a pressure vessel instead of a heat exchanger. The BOG that is generated during LNG bunkering operation is characterized as an intermittent flow with various peak loads. The system was designed to temporarily store the transient BOG inflow, condense it with subcooled LNG and store the condensed liquid. The superiority of the system was verified by comparing it with the most extensively employed conventional re-liquefaction system in terms of consumption energy and via an exergy analysis. Static simulations were conducted for three compositions; the results indicated that the proposed system provided 0 to 6.9% higher efficiencies. The exergy analysis indicates that the useful work of the conventional system is 24.9%, and the useful work of the proposed system is 26.0%. Process dynamic simulations of six cases were also performed to verify the behaviour of the BOG recondenser system. The results show that the pressure of the holdup in the recondenser vessel increased during the BOG inflow mode and decreased during the initialization mode. The maximum pressure of one of the bunkering cases was 3.45 bar. The system encountered a challenge during repetitive operations due to overpressurizing of the BOG recondenser vessel.

  12. Experimental study on the evaporation of phosphoric acid in natural circulation under low temperature%磷酸自然循环低温蒸发实验研究

    Institute of Scientific and Technical Information of China (English)

    陈建利; 王魁; 刘德春; 夏素兰; 朱家骅

    2011-01-01

    国内大型磷酸装置普遍面临浓缩能力不足的问题,回收工艺过程中低温位余热进行稀磷酸低温预浓缩是解决此问题的方案之一。在低于30℃下进行湿法磷酸自然循环浓缩实验研究,获得了彬(P20,)O%~40%的磷酸溶液循环启动工况下垂直上升管内气液两相流沸腾传热平均给热系数377~1047w/(m^2·K),与之对应的管内壁温度35~45℃。实验结果表明,磷酸自然循环低温蒸发具有流体动力学稳定性,适于利用低温位热源。%Using the recycled waste heat with low temperature to concentrate dilute phosphoric acid is one of the methods for solving the deficiency of concentration capacity in large-scale WPA plant in China. Experiments on evaporation of WPA in natural circulation under temperature below 30°C are carried out. The average heat transfer coefficient of the gas-liquid two phase flow upwards in the vertical tube is of 377 - 1 047 W/ ( m2·K) under conditions of circulation starting with w (P205) of 0% - 40% and the corresponding temperature of inside-wall of the tube of 35- 45 °C. The result indicates: the evaporation of phosphoric acid in natural circulation under low temperature bears stability of hydro dynamics and goes well with utilization of low grade heat source.

  13. 多重耦合自然循环载热系统瞬态特性及其热工水力解耦%Transient Characteristics and Thermo-hydraulic Decoupling of Multi-coupled Natural Circulation Heat Transport Systems

    Institute of Scientific and Technical Information of China (English)

    李晓伟; 宋宇; 吴莘馨; 李笑天

    2014-01-01

    The thermo-hydraulic of multi-coupled natural circulation heat transport sys-tems has the characteristics of flow-and-heat-transfer coupling and between-loop coupling .In this paper ,theoretical and numerical methods were used to investigate the natural circulation start-up time ,circulation direction and thermo-hydraulic decoupling of the multi-coupled natural circulation systems .A transient flow model for a natural circulation loop was proposed ,which can predict the start-up time and flow decay of a natural circulation loop . The predictions coincide with numerical simulation . The circulation direction of a natural circulation loop with zero initial velocity was determined by the orientations of the heating and cooling surfaces .The vertical arrangement of the heating and cooling surfaces will make the system have an intrinsic circulation direction . However ,when the initial velocity is reverse to the intrinsic circulation direction and exceeds a critical value , it can make the circulation direction reverse to its intrinsic direction .A simple decoupling analysis method of the thermo-hydraulic of multi-coupled natural circulation heat transport systems was proposed . It can quickly predict the thermal-hydraulic parameters of a multi-coupled natural circulation system .Both theory and calculation show that the heat transfer capacity of a natural circulation loop is proportional to 1 .5 power of the temperature difference of the heating and cooling sources .%多重耦合自然循环载热系统热工水力具有流动换热耦合和回路间耦合的特点,本文采用理论分析结合数值计算的方法对自然循环的建立时间、流动方向及多重耦合自然循环系统的热工水力解耦等问题进行了研究。提出了自然循环载热系统瞬态流动的理论模型,该模型能预测自然循环建立时间、流动衰减等现象,模型计算结果与数值计算结果吻合。初始流速为零的

  14. Screening key parameters affecting nitrate natural circulation loop performance based on analytic hierarchy process%基于层次分析法选取影响硝酸盐自然循环回路性能的关键参数

    Institute of Scientific and Technical Information of China (English)

    邵世威; 王凯; 曲世祥; 何兆忠; 陈堃

    2016-01-01

    硝酸盐自然循环回路(Nitrate natural circulation loop,NNCL)中驱动力和阻力在量级上非常接近,由于环境、材料参数、结构参数和运行参数的波动都可能对NNCL系统性能造成不可忽略的影响,因此需要寻找出影响NNCL系统性能的关键参数.层次分析法是一种采用专家经验构造判断矩阵,通过计算参数不同权重供人们决策的系统分析方法.利用层次分析法对影响NNCL系统性能的40个参数进行建立层次结构模型和判断矩阵,通过权重计算从而选出12个关键参数,这些参数既包括物性参数、结构参数,也包括运行参数.通过分析得出NNCL系统运行阶段应关注的关键参数依次为空气入口温度、加热功率和空气流量.%Background:The driving force and resistance in nitrate natural circulation loop (NNCL) are almost in the same magnitude. The system performance of NNCL can be influenced by lots of parameters, such as environment, material, structural and operation condition, thus selection of key parameters affecting NNCL is very important. Purpose:The aim is toidentify the key parameters affecting NNCL reliability.Methods: The analytic hierarchy process (AHP) is an effective method to analyze the importance of each parameter to the NNCL reliability using experts' judgment to structure judgment matrix and calculate the parameters' weight. In this paper, an AHP model and judgment matrix is established for the 40 parameters.Results:12 key parameters are selected including physical parameters, structural parameters and operating parameters.Conclusion: The results show that the most important parameters affecting NNCL reliability are air temperature, heating power and air flow rate in the NNCL operational phase.

  15. Modification of the Filter in the Turbid Circulating Water System at Meishan Steel Hot Rolling Mill and Operating results%梅钢热轧浊循环系统过滤器的改造及运行效果

    Institute of Scientific and Technical Information of China (English)

    邹正东

    2015-01-01

    针对梅钢热轧浊循环系统过滤器出现的问题,进行了详细的分析,并制定了相关改进措施.认为过滤器本体设计、制造存在缺陷,对其改进后,运行稳定性得到了显著提高.%Problems in the high-speed sand filter of the turbid circulating cooling water system at Meishan Steel Hot Rolling Mill were analyzed in detail and corresponding im-provement measures were also drawn up. It was found that the design and manufacture of the filter body had defects and modification was carried out, which has significantly improved op-eration stability.

  16. Standard Practice for Exposure of Cover Materials for Solar Collectors to Natural Weathering Under Conditions Simulating Operational Mode

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1995-01-01

    1.1 This practice provides a procedure for the exposure of cover materials for flat-plate solar collectors to the natural weather environment at temperatures that are elevated to approximate operating conditions. 1.2 This practice is suitable for exposure of both glass and plastic solar collector cover materials. Provisions are made for exposure of single and double cover assemblies to accommodate the need for exposure of both inner and outer solar collector cover materials. 1.3 This practice does not apply to cover materials for evacuated collectors or photovoltaics. 1.4 The values stated in SI units are to be regarded as the standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  17. Endocrine-disrupting chemicals and oil and natural gas operations: Potential environmental contamination and recommendations to assess complex environmental mixtures

    Science.gov (United States)

    Kassotis, Christopher D.; Tillitt, Donald E.; Lin, Chung-Ho; McElroy, Jane A.; Nagel, Susan C.

    2015-01-01

    Background: Hydraulic fracturing technologies, developed over the last 65 years, have only recently been combined with horizontal drilling to unlock oil and gas reserves previously deemed inaccessible. While these technologies have dramatically increased domestic oil and natural gas production, they have also raised concerns for the potential contamination of local water supplies with the approximately 1,000 chemicals used throughout the process, including many known or suspected endocrine-disrupting chemicals.Objectives: We discuss the need for an endocrine component to health assessments for drilling-dense regions in the context of hormonal and anti-hormonal activities for chemicals used.Methods: We discuss the literature on 1) surface and ground water contamination by oil and gas extraction operations, and 2) potential human exposure, particularly in context of the total hormonal and anti-hormonal activities present in surface and ground water from natural and anthropogenic sources, with initial analytical results and critical knowledge gaps discussed.Discussion: In light of the potential for environmental release of oil and gas chemicals that can disrupt hormone receptor systems, we recommend methods for assessing complex hormonally active environmental mixtures.Conclusions: We describe a need for an endocrine-centric component for overall health assessments and provide supporting information that using this may help explain reported adverse health trends as well as help develop recommendations for environmental impact assessments and monitoring programs.

  18. Use of Natural-Fiber Bio-Composites in Construction versus Traditional Solutions: Operational and Embodied Energy Assessment

    Directory of Open Access Journals (Sweden)

    Carmen Galan-Marin

    2016-06-01

    Full Text Available During the last decades natural polymers have become more and more frequent to replace traditional inorganic stabilizers in building materials. The purpose of this research is to establish a comparison between the most conventional building material solutions for load-bearing walls and a type of biomaterial. This comparison will focus on load-bearing walls as used in a widespread type of twentieth century dwelling construction in Europe and still used in developing countries nowadays. To carry out this analysis, the structural and thermal insulation characteristics of different construction solutions are balanced. The tool used for this evaluation is the life cycle assessment throughout the whole lifespan of these buildings. This research aims to examine the environmental performance of each material assessed: fired clay brick masonry walls (BW, concrete block masonry walls (CW, and stabilized soil block masonry walls (SW stabilized with natural fibers and alginates. These conventional and new materials are evaluated from the point of view of both operational and embodied energy.

  19. Use of Natural-Fiber Bio-Composites in Construction versus Traditional Solutions: Operational and Embodied Energy Assessment.

    Science.gov (United States)

    Galan-Marin, Carmen; Rivera-Gomez, Carlos; Garcia-Martinez, Antonio

    2016-06-13

    During the last decades natural polymers have become more and more frequent to replace traditional inorganic stabilizers in building materials. The purpose of this research is to establish a comparison between the most conventional building material solutions for load-bearing walls and a type of biomaterial. This comparison will focus on load-bearing walls as used in a widespread type of twentieth century dwelling construction in Europe and still used in developing countries nowadays. To carry out this analysis, the structural and thermal insulation characteristics of different construction solutions are balanced. The tool used for this evaluation is the life cycle assessment throughout the whole lifespan of these buildings. This research aims to examine the environmental performance of each material assessed: fired clay brick masonry walls (BW), concrete block masonry walls (CW), and stabilized soil block masonry walls (SW) stabilized with natural fibers and alginates. These conventional and new materials are evaluated from the point of view of both operational and embodied energy.

  20. Circulation in blast driven instabilities

    Science.gov (United States)

    Henry de Frahan, Marc; Johnsen, Eric

    2016-11-01

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

  1. Code-to-code comparison for analysing the steady-state heat transfer and natural circulation in an air-cooled RCCS using GAMMA+ and Flownex

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, P.G., E-mail: pgr@mtechindustrial.com [School of Mechanical and Nuclear Engineering, North-West University, Private Bag X 6001, Potchefstroom (South Africa); Toit, C.G. du [School of Mechanical and Nuclear Engineering, North-West University, Private Bag X 6001, Potchefstroom (South Africa); Jun, J.S.; Noh, J.M. [Korea Atomic Energy Research Institute, Daedeok-daero 989-111, Yuseong-gu, Daejeon (Korea, Republic of)

    2015-09-15

    Highlights: • The GAMMA+ and Flownex codes are used in the analyses of the air-cooled RCCS system. • Radiation heat transfer comprises the bulk of the total rate of heat transfer. • It is possible to obtain reverse flow through the RCCS standpipes. • It has been found that the results obtained with the two codes are in good agreement. • RCCS remain functional for very high blockage ratios thus supporting the safety case. - Abstract: The GAMMA+ and Flownex codes are both based on a one-dimensional flow network modelling approach and both can account for any complex network of different heat transfer phenomena occurring simultaneously. However, there are notable differences in some of the detail modelling aspects, such as the way in which the convection in the reactor cavity is represented. Despite this, it was found in the analyses of the air-cooled RCCS system that the results provided by the two codes compare very well if similar input values are used for the pressure drop coefficients, heat transfer coefficients and view factors. The results show that the radiation heat transfer comprises the bulk of the total rate of heat transfer from the RPV surface. It is also shown that it is possible to obtain a stable and sustainable steady-state operational condition where the flow is in the reverse direction through the RCCS standpipes, resulting in excessively high values for the concrete wall temperature. It is therefore crucial in the design to ensure that such a flow reversal will not occur under any circumstances. In general the good comparison between the two codes provides confidence in the ability of both to correctly solve the fundamental conservation and heat transfer relations in an integrated manner for the complete RCCS system. Provided that appropriate input values are available, these codes can therefore be used effectively to evaluate the integrated performance of the system under various operating conditions. It is shown here that the RCCS

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

    Science.gov (United States)

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

    2013-11-15

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

  3. Contribution to the study of the thermal and hydrodynamical properties of a two-phase natural circulation flow of normal helium (He I) for the cooling of superconducting magnets; Contribution a l'etude des proprietes thermiques et hydrodynamiques d'un ecoulement d'helium normal (He I) diphasique en circulation naturelle pour le refroidissement des aimants supraconducteurs

    Energy Technology Data Exchange (ETDEWEB)

    Benkheira, L

    2007-06-15

    The method of cooling based on the thermosyphon principle is of great interest because of its simplicity, its passivity and its low cost. It is adopted to cool down to 4,5 K the superconducting magnet of the CMS particles detector of the Large Hadron Collider (LHC) experiment under construction at CERN, Geneva. This work studies heat and mass transfer characteristics of two phase He I in a natural circulation loop. The experimental set-up consists of a thermosyphon single branch loop mainly composed of a phase separator, a downward tube, and a test section. The experiments were conducted with varying several parameters such as the diameter of the test section (10 mm or 14 mm) and the applied heat flux up to the appearance of the boiling crisis. These experiments have permitted to determine the laws of evolution of the various parameters characterizing the flow (circulation mass flow rate, vapour mass flow rate, vapour quality, friction coefficient, two phase heat transfer coefficient and the critical heat flux) as a function of the applied heat flux. On the base of the obtained results, we discuss the validity of the various existing models in the literature. We show that the homogeneous model is the best model to predict the hydrodynamical properties of this type of flow in the vapour quality range 0{<=}x{<=}30%. Moreover, we propose two models for the prediction of the two phase heat transfer coefficient and the density of the critical heat flux. The first one considers that the effects of the forced convection and nucleate boiling act simultaneously and contribute to heat transfer. The second one correlates the measured critical heat flux density with the ratio altitude to diameter. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Arroyo, R.; Rebollo, L. [Union Electrica, SA, Madrid (Spain)

    1993-06-01

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

  5. Hydrothermal circulation along oceanic detachment fault: Constraints on the nature and conditions of syntectonic silicification at the 13°20'N oceanic core complex (Mid-Atlantic ridge)

    Science.gov (United States)

    Bonnemains, D.; Verlaguet, A.; Escartin, J.; Mevel, C.; Andreani, M.

    2016-12-01

    To understand the link between extreme strain localization and fluid flow at long-lived oceanic detachment faults, we present results of geological investigations at the active 13°20'N detachment fault along the Mid-Atlantic ridge (ODEMAR cruise, Nov-Dec13) onboard NO Pourquoi pas? using the ROV Victor6000. During this cruise, we identified and sampled 7 fault outcrops on the flanks of detachment microbathymetric corrugations. These fault surfaces, extending up to 100m laterally, with extension-parallel subhorizontal striations. Sampled fault rocks are breccias containing mainly diabase clasts (often altered) and rare ultramafic clasts. Samples also show striated surfaces indicating strain localization at outcrop to sample scales. These fault rocks, which show pervasive syntectonic silicification during fault exhumation, are not documented along other detachments. To constrain the nature and origin of the silicifying fluids and the conditions of fluid-rock interactions, we combined whole-rock and mineral analyses with a study of fluid inclusions in quartz. Highly silicified samples record high homogenization temperatures (250-350°C), while moderate silicification temperatures are lower (150-250°C). In all cases salinities are generally higher than seawater (4-10 wt% eq. NaCl). These high salinity fluids likely record phase separation at high temperature (>400°C), and Raman spectroscopy shows that they contain H2±CH4±CO2. These results suggest an interaction of these fluids with ultramafic rocks undergoing serpentinization reactions (H2 release) in the footwall of the detachment and the presence of a high temperature zone at depth. This is supported by trace element patterns of mafic breccias, which shift towards ultramafic compositions with increasing silicification degree. The detachment fault zone thus channels and records a tectonic mixing between hydrothermal serpentinite fluids, and shallower seawater-like fluids potentially from the mafic hanging wall.

  6. Analysis of ROSA 1.1 test with TRACE code: ECSS water injection under natural circulation conditions; Analisis con el codigo TRACE del test ROSA 1.1: Inyeccion de agua ECCS bajo condiciones de circulacion natural

    Energy Technology Data Exchange (ETDEWEB)

    Julibe, A. J.; Munoz-Coba, J. L.; Escriva, A.; Romero, A.

    2010-07-01

    This paper is based on modelling the ROSA 1.1 test by TRACE code. The ROSA 1.1 test presents several natural flow phases in biphasic conditions and this was the cause of this work. Therefore, the aim of this paper is verify the TRACE code ability to simulate such flows using standard components and modules.

  7. 基于IAPWS-IF97的自然循环差压测量修正技术%Natural Circulation Differential Pressure Measurement Correction Technology Based on IAPWS-IF97

    Institute of Scientific and Technical Information of China (English)

    郝文涛; 李卫华; 杨星团; 姜胜耀; 刘志勇

    2012-01-01

    The low temperature nuclear heating reactor (NHR), developed by Institute of Nuclear and New Energy Technology of Qinghua University, is highly safe because of its natural circulation at full power level, The driving force of natural circulation is very low, so the flow rate is highly affected by the resistance of the reactor coolant loop. As a result, reducing the flow resistance is a key technology of NHR design. A experiment equipment, which simulated the natural circulation of the reactor coolant loop, was constructed to validate the design. The pressure drop was measured by differential pressure transmitters. The temperature difference of the water in different impulse tubes introduced density difference, which led to large measurement error. Considering the high precision of IAPWS-97, an ActiveX control was developed based on IAPWS-97 to calculate the density of water at deferent pressures and temperatures. The control was used in the data acquisition system based on configuration software platform and the online correction of differential pressure measurement was realized. The testing data analysts shows that the precision of the corrected differential pressure measurement results is highly improved.%清华大学核能与新能源技术研究院所设计的低温供热堆一回路采用全功率自然循环,具有很强的固有安全性.由于自然循环压头低,回路阻力对流量有较大影响,因此,降低一回路阻力是反应堆设计的关键技术之一.为验证设计的正确性,搭建了1个试验回路,模拟一回路自然循环.采用差压变送器测量回路压降时,引压管内水的温度差将导致其密度差,并进而带来很大的测量误差.IAPWS-IF97公式在计算水和蒸汽物性时具有很高的精度,为此,开发了基于该公式的ActiveX控件,计算水在不同温度和压力下的密度.将该控件应用到基于组态软件的数据采集系统中,实现了差压测量的在线修正.数据分析结果表

  8. Modeling of temperature and turbidity in a natural lake and a reservoir connected by pumped-storage operations

    Science.gov (United States)

    Bonalumi, Matteo; Anselmetti, Flavio S.; Wüest, Alfred; Schmid, Martin

    2012-08-01

    Pumped-storage (PS) systems are used to store electric energy as potential energy for release during peak demand. We investigate the impacts of a planned 1000 MW PS scheme connecting Lago Bianco with Lago di Poschiavo (Switzerland) on temperature and particle mass concentration in both basins. The upper (turbid) basin is a reservoir receiving large amounts of fine particles from the partially glaciated watershed, while the lower basin is a much clearer natural lake. Stratification, temperature and particle concentrations in the two basins were simulated with and without PS for four different hydrological conditions and 27 years of meteorological forcing using the software CE-QUAL-W2. The simulations showed that the PS operations lead to an increase in temperature in both basins during most of the year. The increase is most pronounced (up to 4°C) in the upper hypolimnion of the natural lake toward the end of summer stratification and is partially due to frictional losses in the penstocks, pumps and turbines. The remainder of the warming is from intense coupling to the atmosphere while water resides in the shallower upper reservoir. These impacts are most pronounced during warm and dry years, when the upper reservoir is strongly heated and the effects are least concealed by floods. The exchange of water between the two basins relocates particles from the upper reservoir to the lower lake, where they accumulate during summer in the upper hypolimnion (10 to 20 mg L-1) but also to some extent decrease light availability in the trophic surface layer.

  9. A coupled human-natural system to assess the operational value of weather and climate services for agriculture

    Science.gov (United States)

    Li, Yu; Giuliani, Matteo; Castelletti, Andrea

    2017-09-01

    Recent advances in weather and climate (W&C) services are showing increasing forecast skills over seasonal and longer timescales, potentially providing valuable support in informing decisions in a variety of economic sectors. Quantifying this value, however, might not be straightforward as better forecast quality does not necessarily imply better decisions by the end users, especially when forecasts do not reach their final users, when providers are not trusted, or when forecasts are not appropriately understood. In this study, we contribute an assessment framework to evaluate the operational value of W&C services for informing agricultural practices by complementing traditional forecast quality assessments with a coupled human-natural system behavioural model which reproduces farmers' decisions. This allows a more critical assessment of the forecast value mediated by the end users' perspective, including farmers' risk attitudes and behavioural factors. The application to an agricultural area in northern Italy shows that the quality of state-of-the-art W&C services is still limited in predicting the weather and the crop yield of the incoming agricultural season, with ECMWF annual products simulated by the IFS/HOPE model resulting in the most skillful product in the study area. However, we also show that the accuracy of estimating crop yield and the probability of making optimal decisions are not necessarily linearly correlated, with the overall assessment procedure being strongly impacted by the behavioural attitudes of farmers, which can produce rank reversals in the quantification of the W&C services operational value depending on the different perceptions of risk and uncertainty.

  10. 非能动安全壳冷却系统空气流道自然循环的比例分析与设计%Scaling Analysis and Design for PCS Air Flow Path Natural Circulation

    Institute of Scientific and Technical Information of China (English)

    刘卓; 常华健; 阳祥; 杨燕宁

    2016-01-01

    在考虑建设试验台架经济性的前提下,缩小比例的单项和整体效应试验台架对研究和开发大型先进压水堆核电站及其分析验证程序都具有重要意义。非能动安全壳冷却系统(PCS )壳外空气流道内的自然循环在安全壳非能动冷却性能中发挥着重要的作用。本文从自然循环的数学模型出发,推导出了单项和整体效应试验台架的比例设计方法。在给定壳内热流密度的条件下,通过PCCSAP‐3D程序对C A P1400非能动安全壳的2/5比例单项效应试验理想比例台架(IS F )进行模拟。结果表明,本比例分析与设计方法以及在降低高度台架上模拟自然循环是可行的。%The scale‐down separate and integral effect test facilities are of vital signifi‐cance not only for the research and development of large‐scale advanced pressurized w ater reactor nuclear pow er plants ,but also for validation and verification of the related analysis codes . The passive containment cooling system (PCS ) air flow path system plays an important role in containment passive cooling .Based on the natural circulation model ,the scaling and design methods for both the separate and integral effect test facil‐ities were proposed .Under given heat flux from the inner side of the shell ,simulation of an ideal scaled facility (ISF) design of a 2/5 length scaled separate effect test facility for CAP1400 PCS was preliminarily performed by the PCCSAP‐3D code .The simulation results show that the design method and the modeling of natural circulation on a reduced height test facility are feasible .

  11. Nature/culture/seawater.

    Science.gov (United States)

    Helmreich, Stefan

    2011-01-01

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

  12. Pythagoras's theorem on a two-dimensional lattice from a 'natural' Dirac operator and Connes's distance formula

    Energy Technology Data Exchange (ETDEWEB)

    Dai Jian [Theory Group, Department of Physics, Peking University, Beijing (China)]. E-mail: jdai@mail.phy.pku.edu.cn; Song Xingchang [Theory Group, Department of Physics, Peking University, Beijing (China)]. E-mail: songxc@ibm320h.phy.pku.edu.cn

    2001-07-13

    One of the key ingredients of Connes's noncommutative geometry is a generalized Dirac operator which induces a metric (Connes's distance) on the pure state space. We generalize such a Dirac operator devised by Dimakis et al, whose Connes distance recovers the linear distance on an one-dimensional lattice, to the two-dimensional case. This Dirac operator has the local eigenvalue property and induces a Euclidean distance on this two-dimensional lattice, which is referred to as 'natural'. This kind of Dirac operator can be easily generalized into any higher-dimensional lattices. (author)

  13. Expression and function of store-operated calcium channels in human circulating fibrocytes%钙库操纵性钙通道在人循环纤维细胞中的表达及功能

    Institute of Scientific and Technical Information of China (English)

    钟金男; 兰兰; 何光珍; 黄革; 杨炯; 高亚东

    2016-01-01

    目的:研究钙库操纵性钙通道(store-operated calcium channels,SOCC)相关功能蛋白ORAI1-3和STIM1-2在人循环纤维细胞(circulating fibrocytes)中的表达及SOCC对人循环纤维细胞分化的影响.方法:采集健康人外周静脉血,分离出单个核细胞,体外培养分化为循环纤维细胞.采用RT-PCR和real-time PCR检测循环纤维细胞中ORAI1-3及STIM1-2的mRNA表达情况,并检测SOCC抑制剂对循环纤维细胞分化的影响.结果:Real-time PCR检测结果显示ORAI1-3和STIM1-2 mRNA在循环纤维细胞中有较高的表达水平,并且SOCC抑制剂SKF-96365对循环纤维细胞分化具有明显的抑制作用.结论:SOCC表达于循环纤维细胞中,并且影响循环纤维细胞的分化.%AIM:To investigate the expression and function of store-operated calcium channels ( SOCC) in human circulating fibrocytes.METHODS:Peripheral blood mononuclear cells ( PBMCs) were isolated and cultured in ser-um-free media.After 7 d, the PBMCs differentiated into fibrocytes.RT-PCR and real-time PCR were performed to deter-mine the mRNA expression of ORAI1-3 and STIM1-2 in the fibrocytes.SOCC inhibitor SKF-96365 was used to elucidate the role of SOCC in the differentiation of fibrocytes.RESULTS:The results of real-time PCR showed that the mRNA ex-pression of ORAI1-3 and STIM1-2 was positive in cultured fibrocytes.SKF-96365 (10μmol/L) significantly inhibited the differentiation of fibrocytes.CONCLUSION:SOCC-related proteins ORAI1-3 and STIM1-2 are abundantly expressed in the fibrocytes, and may play an important role in the differentiation of these cells.

  14. Operation analysis and optimization research of natural gas dehydration system%天然气脱水系统现状分析及优化

    Institute of Scientific and Technical Information of China (English)

    陈秀娜; 范峥; 李稳宏; 贾浩民; 闫昭; 赵聪; 李珍

    2012-01-01

    针对陕北某天然气净化厂脱水系统中原料气水含量偏高、产品气无法满足国标要求这一生产难题,本文利用ChemCAD对该脱水系统进行了全流程模拟,研究分析得到最佳的优化操作参数为:TEG循环量为6.16m3/h,原料气进气温度为33℃。通过FRI、HTRI和Pipe Flow Expert等专业软件对系统改造后的关键设备及管线进行优化,核算结果表明,脱水塔的各个流体力学参数均可满足生产需要;套管换热器换热能力不足,通过对比分析可知选用高效板式换热器替代在役套管换热器是一种较为经济、合理的优化方案;通过提高原料气预冷器换热管束的表面翅化率可以有效改善它的换热效果,使其达到系统指定的换热要求。研究结果可为该脱水系统的升级改造提供可靠的理论依据,对同类型装置亦具有一定的借鉴作用。%The water content of the feed gas in dehydration system for a natural gas purification plant located in northern Shaanxi was too high and product gas could not meet the national standard.In order to resolve the problem ChemCAD was used to simulate the whole process and analyze the main influence factors.The best optimized operating parameters were as follows:the circulation quantity of TEG was 6.16m3/h,the temperature of feed gas was 33℃.Some professional software containing FRI,HTRI,Pipe Flow Expert and so on were used to optimize the relevant key equipment and pipelines after system transformation.The calculation result demonstrated that hydrodynamic parameters of TEG contactor would satisfy the operation requirement.The duty of jacketed pipe exchanger was deficient.The contrast analysis result showed that the selection of an efficient plate heat exchanger to replace the jacketed pipe exchanger in service was an economical and reasonable optimization method.The bundle finning ratio of feed gas precooler needed to be increased to improve heat transfer in order to be

  15. Natural and human drivers of salinity in reservoirs and their implications in water supply operation through a Decision Support System

    Science.gov (United States)

    Contreras, Eva; Gómez-Beas, Raquel; Linares-Sáez, Antonio

    2016-04-01

    changes from 3800 to 5100 μScm-1 in the deepest layers are found with a similar daily water inflow. On the other hand, when reservoir water level is low, salinity increases around 1000 μScm-1 are found with a 2 m water level falling. In view of the influence of water level in the reservoir dynamics, this factor should be considered when dam operation decisions are taken by managers in terms of satisfying the water demand. The results will be implemented in a Decision Support System that is being displayed in the Guadalhorce River and which includes prediction of water quantity and quality in the reservoir in terms of salinity, involving water level and water inflow forecasting as the main factors to control the state of the reservoir and therefore with implications in water management. This methodology could be implemented in other reservoirs with high salinity and be adapted to other substances (such as nutrients and heavy metals) associated to water inflow in water bodies where water quality and quantity are driven by human decisions factors besides natural factors such as floods and dynamics of flows in the reservoir.

  16. Operation Characteristics of Fluidized Bed Heat Exchanger of Large-scale Circulating Fluidized Bed Boiler%大型循环流化床锅炉外置换热器运行特性分析

    Institute of Scientific and Technical Information of China (English)

    张缦; 吴海波; 孙运凯; 吕清刚

    2012-01-01

    为掌握大型循环流化床(circulating fluidized bed,CFB)锅炉外置换热器(fluidized bed heat exchanger,FBHE)的运行特性,在2台实际运行的300MW CFB锅炉上进行了运行特性测试研究,包括FBHE对CFB锅炉床温、汽温的调节及其传热特性的研究。结果表明:带FBHE的CFB锅炉炉膛温度沿炉膛高度分布比较均匀,且在60%锅炉最大连续蒸发量(boiler maximum continue rate,BMCR)以上运行时床温无明显变化,而无FBHE的CFB锅炉床温随负荷变化明显,炉膛温度沿炉膛高度差别较大,且随着锅炉负荷的降低,差别更明显;锥型阀的开度随锅炉负荷的增加而增大;在负荷不变的情况下,过热器的喷水量和再热器的吸热量随床温的升高递减,但减少幅度较小;不同负荷下FBHE内不同受热面的传热系数不同,其值均随负荷的增加单调增大。%In order to investigate the operation characteristics of fluidized bed heat exchanger(FBHE) of large-scale circulating fluidized bed(CFB) boiler,experiments were conducted on two 300 MW CFB boilers which have been put into commercial operation,including the effect of FBHE on the adjustment characteristics of furnace temperature and steam temperature of CFB boiler and heat transfer characteristics of FBHE.The results indicate that the furnace temperature of CFB boiler with FBHE is quite even along the height direction,and there is almost no change in temperature when the boiler operates at above 60% boiler maximum continue rate(BMCR),whereas the furnace temperature of CFB boiler without FBHE is quite different,such difference becomes more obvious with the boiler load decreasing.The opening of cone valve increases monotonously along with the boiler load increasing.In the condition of constant load,when the bed temperature rises superheater water spray and reheater heat absorption decreases but at a relatively low degree.At different boiler loads,the heat transfer coefficients of

  17. 高浓度循环水下跳汰机操作参数的调整%Adjustment of operating parameters of jigger under higher concentration circulating water

    Institute of Scientific and Technical Information of China (English)

    王敏; 金吉元; 刘新国

    2011-01-01

    由济三选煤厂原煤筛分试验和煤泥水筛分试验可知,原煤泥化现象严重,煤泥水处理能力低,循环水中细粒级含量较高,导致循环水浓度升高,高浓度循环水是影响跳汰机分选效果的主要原因.通过调整进气蝶阀、排气蝶阀,设置风压频率和调整水量等措施对跳汰机操作参数进行了调整,并通过三产品分配率曲线对调整效果进行了验证,结果表明:三产品跳汰机分配率曲线较陡,可能偏差EP1、Ep2,不完善度I1、I2均小于0.1,跳汰机分选效果良好.调整跳汰机操作参数后,济三选煤厂产品质量结构得到优化,省去了配煤洗混的麻烦;精煤灰分合格率达到100%,精煤产率提高了3%;原煤入洗能力提高了120 t/h,超额完成了选煤厂生产指标.%Raw coal screening experiments and coal water slurry screening experiments in Jining NO. 3 coal preparation plant show that the raw coal is extremely sliming and the efficient of processing system is lower, there are also large amount of fine particles in circulating water, higher concentration of circulating water is the main cause of lower separation efficiency. The operating parameters have been adjusted by adjusting gas inlet and outlet butterfly valves, resetting wind pressure frequency, regulating flow of circulating water and so on. Adjustment effect have been tested by three products distribution rate curve. The results show that the the slope of curve is larger, the possible deviation EP1、EP2 .imperfection I1, I2 are above 0. 1 ,the jigging effect is better. After adjument,the quality of products have been improved, also have saved the plant the trouble of bulk flotating for blending coal, cleans ash has reached 100% ,the clean coal productive has been improved by 3% .processing capability is up 120 t/h. The productive task has been overfulfilled.

  18. Proper Sizing of Circulation Pumps

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Nørgaard, Jørgen

    2007-01-01

    , but the results can be applied to Europe in general. Despite the small sample of houses involved in the test, 15 houses, some rather safe conclusions can be drawn from the results, which showed that newly developed pumps with power consumption around 5-8 W, can perform the task of circulating the water...... sufficiently to keep the houses satisfactorily warm during the heating season of the test. The old replaced pumps used 5-10 times more power. In Europe alone, a gradual replacement of the present vastly oversized pumps with such small but sufficient pumps can save the construction of 17 large power plants...... as well as their pollution during operation. Policy measures are proposed of how to ensure that in the future only such energy saving pumps are installed. Furthermore, on the basis of the historic experiences with circulation pumps some con¬clusions are drawn on how to investigate, develop and market new...

  19. How operational Advanced-DInSAR Analysis can improve knowledge on natural and anthropogenic deformations for Nuclear Power Plant areas

    Science.gov (United States)

    Vollrath, Andreas; Zucca, Francesco; Stramondo, Salvatore; Bignami, Christian; Roeder, Johannes

    2015-04-01

    The application of Advanced Differential Interferometric Synthetic Aperture Radar (A-DINSAR) techniques has strongly emerged in the last two decades and became an important part in georelated fields. State-of-the-art A-DInSAR methods, such as Persistent Scatterer Interferometry (PSI) or the Small BASeline (SBAS) approach have demonstrated their usefulness in monitoring urban areas and single buildings, up to critical infrastructures. Combined with additional data from GPS networks or levelling, it could prove its large potential for an operational, cost-effective mapping of surface deformations. Given a reasonable amount of images, changes in surface deformation can be detected down to 1 mm/y. Compared to point-wise field measurements it offers a spatially consistent mapping approach from local to regional scales. In this review we want to provide a synopsis how A-DInSAR can be utilized in the framework of Nuclear Power Plant safety. Indeed, A-DInSAR is able to provide a detailed spatial analysis of slow movements occurring at NPP structures directly, as well as within the surrounding areas of the NPPs. Different phenomena of surface motion can be subject of such a monitoring. Natural causes, like active tectonics and terrain instability of slope which lead to landslides, as well as human-induced subsidence phenomena due to heavy construction or water pumping can be detected. We start by presenting techniques to determine the feasibility of the analysis for a given area and show its limitations. Then we propose a short insight into state-of-the-art studies where landslides, interseismic and human-induced deformation of the surface were mapped by A-DInSAR, to point out the relevance of a consequent analysis over an area of a NPP. Furthermore we present results of case studies from international projects (TERRAFIRMA) as well as preliminary results from the Krsko NPP in Slovenia. Finally, we provide a outlook into present and future trends concerning the use of freely

  20. Study on Chaotic Characteristics of Natural Circulation Flow Instability Under Rolling Motion%摇摆条件下自然循环流动不稳定性的混沌特性研究

    Institute of Scientific and Technical Information of China (English)

    张文超; 谭思超; 高璞珍; 张虹; 张红岩

    2012-01-01

    对摇摆条件下两相自然循环系统不规则复合型脉动进行了非线性时序分析.通过相空间重构计算了不规则复合型脉动时间序列的关联维、K2熵和最大Lyapunov指数值,在几何不变量的计算结果基础上,结合密度波型脉动和波谷型脉动的对比,分析了不规则复合型脉动的混沌特征和产生机理.分析结果表明:不规则复合型脉动为典型的混沌运动,热驱动力、流动阻力和摇摆引起的附加外力的相互作用和耦合导致了混沌的出现.%Non-linear time series analysis on irregular complex flow oscillations of natural circulation system under rolling motion was studied. The correlation dimension, Kz entropy and maximal Lyapunov exponent (MLE) were determined based on phase space reconstruction theory. The chaotic features of the irregular complex flow oscillations were analyzed by comparing with density wave oscillation and trough-type flow oscillation base on the results of geometric invariants. The results indicate that irregular complex flow oscillations are typical chaotic oscillations, the interaction and feedback of thermal driving forces, flow resistance and additional forces caused by rolling motion lead to the emergence of chaos.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Margaret R Dunne

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

  3. [Effect of 5 warm-hot nature Chinese drugs for promoting blood circulation and removing blood stasis on 5-HT, NE, and endocrine hormones of rats of cold coagulation and blood stasis syndrome].

    Science.gov (United States)

    Wang, Peng; Fu, Xian-Jun; Zhou, Yang; Wang, Zhen-Guo

    2014-11-01

    To study the mechanism of warm-hot nature Chinese drugs (WHNCD) for promoting blood circulation and removing blood stasis (PBCRBS) for intervening model rats of cold coagulation and blood stasis syndrome (CCBSS). CCBSS rat model was set up in outbred SD rats using ice water immersion method. Totally 300 successfully modeled CCBSS rats were randomly divided into 5 groups according to the principle of balance weight, 60 in each group. Contents of triothyrone (T3), tetraiodothyroine (T4), progesterone (P), 5-hydroxytryptamine (5-HT), and noradrenalin (NE) were paralleledly detected in all groups. Then rats in each group were subdivided into 6 subgroups as the model group, the curcuma group, the Ligsticum Chuanxiong group, the safflower group, the Rhizoma Corydalis group, and the Olibanumg group. Besides, 5 normal control groups were set up for 5 indices, 50 rats in total. We need 70 rats (7 groups) to finish observing 1 index, 350 rats in total for 5 indices. Except those in the model group and the normal control group, rats were administered with corresponding decoction at 20 g crude drugs/kg body weight by gastrogavage, 3 mL each time, once daily for 7 successive days. Equal volume of normal saline was given to rats in the normal control group and the model group. Contents of T3, T4, P, 5-HT, and NE were detected before treatment and 1 week after treatment. Compared with before treatment in the same group, T3 increased in the Ligsticum Chuanxiong group and the Olibanumg group, 5-HT increased in the Ligsticum Chuanxiong group, T4, NE, and P increased in all medicated groups (P endocrine system, which might be one of the pharmacodynamic mechanism of WHNCD for PBCRBS in intervening CCBSS.

  4. Organization and operation of the sixth international symposium on the natural radiation environment (NRE VI). Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hopke, P.K.

    1995-12-31

    An important source of human exposure to radiation is the natural world including cosmic rays, cosmogonic radionuclides, natural terrestrial radionuclides, and radon isotopes and its decay products. Considerable effort is being expended on a worldwide basis to characterize the exposure to the natural radiation environment and determine the important pathways for the exposure to result in dose to tissue that leads to injury and disease. The problem of background exposure to naturally occurring radioactivity has been the subject of research since the initial discovery of the radioactivity of uranium and thorium. However, with the advent of artificial sources of radiation with both benefits (medical x-rays and nuclear medicine), and harm (Chernobyl fallout), the nature and magnitude of the natural radiation environment and the effects on various populations are important in the development of overall public health strategies as ALARA principles are applied. To facilitate the exchange of information and the review of uncertainties and scientific research priorities, a series of 5 international meetings on Natural Radiation Environment, 1963, 1987, 1991. This conference (Montreal, 1995) covers the range of natural radiation environments that give rise to human exposure and dose. This document is a program summary.

  5. 气-液-固自然循环流化床中的流动特性和压降%Flow Properties and Pressure Drop of Gas-Liquid-Solid Natural Circulating in Fluidized-Bed

    Institute of Scientific and Technical Information of China (English)

    齐国鹏; 姜峰; 赵燕禹; 赵国华; 周震; 李修伦

    2009-01-01

    A fluidized-bed evaporator for gas-liquid-solid natural circulation was set up to research the flow and distribution of solid particles and pressure drop of liquid-solid two-phase flow in a heating pipe bundle. With CCD image collecting and processing system,the influences of the particle kinds,particle holdup and additive air amount were studied. The experimental results show that air inlet positions have much effect on the distribution of solid particles in the heating pipe bundle. The form of moving and fluidization of solid particles in up-channel is different from that in down-channel. In up-channel,solid particles make circulating movement with the central part rising and perimeter dropping. As the density decreases,the distribution of solid particles in up-channel gradually becomes uniform. In down-channel,solid particles form two big whirls at both sides of the central axis. As additive air amount increases,the rotation rate of whirls increases. When the air is input from the up-channel,the pressure drop of liquid-solid two-phase flow in the heating pipe bundle increases with the increase of particles holdup and air amount. The pressure drop model of liquid-solid two-phase flow in the heating pipe bundle has been set up,and the calculated data agree well with the experimental results.%建立了气-液-固冷模多管自然循环流化床蒸发器,利用CCD图像采集和处理系统,研究了固体颗粒的种类、含率和通气量等操作参数对于固体颗粒的流化和运动形态、分布以及加热管束中液-固两相流压降的影响.结果表明:通气位置对于固体颗粒在加热管束中的分布影响较大.在上、下管箱中,固体颗粒的运动和流化形态不同.在上管箱中,固体颗粒形成中心上升、四周下降的循环运动,并且随着其密度的降低,固体颗粒在上管箱中的分布逐渐趋向均匀;在下管箱中,固体颗粒在中心轴的两侧形成两个大的旋涡,旋涡的旋转速度随着

  6. Optimizing the operation of the Qingshitan Reservoir in the Lijiang River for multiple human interests and quasi-natural flow maintenance

    Institute of Scientific and Technical Information of China (English)

    Qiuwen Chen; Duan Chen; Ruiguang Han; Ruonan Li; Jinfeng Ma; Koen Blanckaert

    2012-01-01

    For reservoir operation,maintaining a quasi-natural flow regime can benefit river ecosystems,but may sacrifice human interests.This study took the Qingshitan Reservoir in the Lijiang River as a case,and developed an optimization model to explore a trade-off solution between social-economic interests and nature flow maintenance on a monthly base.The objective function considered irrigation,cruise navigation and water supply aspects.An index of flow alteration degree was proposed to measure the difference between the regulated discharge and the natural flow.The index was then used as an additional constraint in the model besides the conventional constraints on reservoir safety.During model solving,different criteria were applied to the index,representing various degrees of alteration of the natural flow regime in the river.Through the model,a relationship between social-economic interests and flow alteration degree was established.Finally,a trade-off solution of the reservoir operation was defined that led to a favorable social-economic benefit at an acceptable alteration of the natural flow.

  7. Mountains and Tropical Circulation

    Science.gov (United States)

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

    2015-12-01

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

  8. Operation of the NETL Chemical Looping Reactor with Natural Gas and a Novel Copper-Iron Material

    Energy Technology Data Exchange (ETDEWEB)

    Straub, Douglas [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Bayham, Samuel [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Weber, Justin [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

    2017-02-21

    The proposed Clean Power Plan requires CO2 emission reductions of 30% by 2030 and further reductions are targeted by 2050. The current strategies to achieve the 30% reduction targets do not include options for coal. However, the 2016 Annual Energy Outlook suggests that coal will continue to provide more electricity than renewable sources for many regions of the country in 2035. Therefore, cost effective options to reduce greenhouse gas emissions from fossil fuel power plants are vital in order to achieve greenhouse gas reduction targets beyond 2030. As part of the U.S. Department of Energy’s Advanced Combustion Program, the National Energy Technology Laboratory’s Research and Innovation Center (NETL R&IC) is investigating the feasibility of a novel combustion concept in which the GHG emissions can be significantly reduced. This concept involves burning fuel and air without mixing these two reactants. If this concept is technically feasible, then CO2 emissions can be significantly reduced at a much lower cost than more conventional approaches. This indirect combustion concept has been called Chemical Looping Combustion (CLC) because an intermediate material (i.e., a metal-oxide) is continuously cycled to oxidize the fuel. This CLC concept is the focus of this research and will be described in more detail in the following sections. The solid material that is used to transport oxygen is called an oxygen carrier material. The cost, durability, and performance of this material is a key issue for the CLC technology. Researchers at the NETL R&IC have developed an oxygen carrier material that consists of copper, iron, and alumina. This material has been tested extensively using lab scale instruments such as thermogravimetric analysis (TGA), scanning electron microscopy (SEM), mechanical attrition (ASTM D5757), and small fluidized bed reactor tests. This report will describe the results from a realistic, circulating, proof-of-concept test that was

  9. 自然循环换热器壳侧传热及流动的数值模拟%Numerical Simulation of Shell-Side Heat Transfer and Flow of Natural Circulation Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    薛若军; 邓程程; 李朝君; 王明远

    2012-01-01

    In order to analyze the influence on the heat transfer and flow characteristics of the heat exchanger model of different solving models and structures, a variety of transformation to the model equivalent for the heat exchanger was studied. In this paper, Fluent software was used to simulate the temperature-field and flow-field of the equivalent model, and investigate its heat-transferring and flow characteristics. Through comparative analysis of the distribution of temperature-field and flow-field for different models, the heat-transferring process and natural convection situation of heat exchanger were deeply understood. The results show that the temperature difference between the inside and outside of the natural circulation heat exchanger tubes is larger and the flow is more complex, so the turbulence model is the more reasonable choice. Asymmetry of tubes position makes the flow and heat transfer of the fluid on both sides to be dissymmetrical and makes the fluid interaction, and increases the role of natural convection. The complex structure of heat exchanger makes the flow and heat transferof the fluid on both sides to be irregular to some extent when straight tubes into C-bent are transformed, and all these make the turbulence intensity increase and improve the effect of heat transfer.%为分析换热器的求解模型和内部结构的不同对传热和流动特性的影响,用等效自然循环换热器的模型进行多种变换.用Fluent软件对等效模型进行非稳态数值模拟,研究其传热和流动特性.通过比较分析不同模型的温度场和流场的变化,对该换热器的传热过程和自然对流情况有较深刻的认识.结果表明:自然循环换热器的传热管内外温差较大,且流动较复杂,选用湍流模型计算更为合理;传热管位置的不对称性,引起左右两侧传热和流动的不对称性,使得流体相互影响,增强了自然对流作用;传热管的形状由直管变为C型弯管,结构的

  10. Experimental investigation of a natural circulation parabolic trough collector system for medium-high temperature steam generation%自然循环槽式太阳能中高温集热系统实验研究

    Institute of Scientific and Technical Information of China (English)

    陈欢; 王红梅; 俞自涛; 胡亚才; 张良; 倪煜; 樊建人

    2012-01-01

    A 50 kW natural circulation parabolic trough collector (PTC) system for medium-high temperature steam generation was proposed. Experimental investigation of thermal performance and stability was performed under different solar irradiation and discharging steam pressure conditions. Results show that the requirement of minimum solar irradiation perpendicular to the mirror for system working steadily is 254-272 W/m2. In good irradiation condition of summer, this system can generate steam at pressure up to 0. 5 MPa stably in one day. When three days continuous heating is performed, the pressure of saturated steam generated by the system reaches to 0. 8 MPa. During the steam producing process at different pressure, there is subcooling heat transfer happening due to insufficient solar radiation and thermal losses of pipes which result in inadequate heat fluxes in heat pipe.%介绍了规模为50 kW的自然循环槽式太阳能中高温集热系统,并对系统在不同太阳辐照和排汽压力工况下的传热特性及稳定性进行了实验研究.结果表明,系统稳定运行的最低有效辐照条件为垂直镜面辐照度254~272 W/m2;在较好的辐照条件下,本系统能够实现当天0.5 MPa稳定排汽;在连续3d良好辐照条件下,系统产生的饱和蒸汽压力达到0.8 MPa.在不同压力工况排汽过程中,由于辐照强度较小,管道热损失偏大,热管流量和携带热量偏小,自然循环换热系统均出现了不同程度的过冷换热现象.

  11. 摇摆运动下单相自然循环核热耦合特性研究%Nuclear Thermal Coupling Characteristics of Single-phase Natural Circulation Under Rolling Motion

    Institute of Scientific and Technical Information of China (English)

    张连胜; 张红岩; 谭思超; 张文超; 高璞珍; 张虹

    2013-01-01

    采用考虑6组缓发中子的点堆中子动力学模型,开发了核反馈模拟模块,并将之与摇摆条件下单相自然循环热工水力计算模型进行合并,基于Matlab软件编制了相应的计算程序,实现了摇摆条件下单相自然循环核热耦合的模拟计算。计算结果表明:摇摆条件下,与不考虑核反馈相比,考虑核反馈后核热耦合效应使系统流量降低,系统功率产生波动;系统功率的平均值随摇摆频率及振幅的增大而降低,而系统功率的振幅则随摇摆周期及振幅的增大而增大。核热耦合效应使燃料元件温度的波动振幅减小,起到了抑制燃料温度波动的作用。%A nuclear feedback simulation module adopting the point reactor neutron kinetics model with six delayed neutron precursor groups was proposed . A program which combines a nuclear feedback module with the thermal-hydraulic calculation model to simulate the natural circulation under rolling motion in Matlab platform was developed .The results show that the average flow rate and heating power decrease when considering the nuclear thermal coupling effect under rolling motion condition . The average value of the heating power decreases with the increase of the rolling frequency and rolling amplitude . The oscillation amplitude of the heating power increases with rolling period and rolling amplitude .Furthermore ,the nuclear thermal coupling effect decreases the fluctuation amplitude of the fuel temperature ,playing a positive role in suppressing the temperature fluctuations .

  12. Investigation on Installation height of Storage Tank for Natural Circulation Flat Plate Solar Collector%自然循环平板式太阳能热水器水箱放置高度的研究

    Institute of Scientific and Technical Information of China (English)

    郑土逢; 李明; 魏生贤; 罗熙; 王炳灿

    2011-01-01

    The device of natural circulation flat plate solar water heater has been built.In accordance with the national testing standard methods, the efficiency of the system was tested.The transient model of NFSWH has been developed by using the TRNSYS simulation program.The effect of installation height between the bottom of the tank and the outlet of the collector on efficiency of the solar collector has been investigated both theoretically and experimentally.The data show the theoretical results are highly consistent with the experimental ones.Results indicate that the optimum value of installation height is 0.74m with the maximum efficiency of 67.5% for the system with a total area of 1.5m2 and a storage water tank capacity of 120L.When the installation height is between 0.44 and 1.04 m, the change of thermal efficiency of the solar system is at a range of 3%.%搭建了自然循环平板式太阳能热水器(NFSWH)的实验平台,根据太阳能热水器国家测试标准方法对系统的热效率进行测试.用TRNSYS软件建立了NFSWH的瞬态模型.模拟和实际测量了水箱放置高度对热水器热效率的影响.结果显示,实验与模拟吻合较好.对于集热面积为1.5m2水箱容积为120L的系统,水箱底到集热器出口的高度(Hr)为0.74m时,系统的热效率最大(67.7%).放置高度为0.44-1.04m时,系统集热效率变化不大,在3%以内.

  13. 小型自然循环钠冷堆堆芯初步设计研究%Preliminary Design Research on Core of Small Natural-circulation Sodium-cooled Reactor

    Institute of Scientific and Technical Information of China (English)

    陆道纲; 张勋

    2014-01-01

    A small natural-circulation sodium-cooled reactor-AM TEC system was pres-ented as a distributed generation system . According to the criticality calculation and thermal-hydraulic analysis of the core when the total fuel mass was constant ,the influ-ence of pellet radius ,fuel pin length and the number of rings of fuel pins upon the effec-tive multiplication factor kef , pressure drop across the core and heat transfer was analyzed .Additionally ,the B4 C absorber thickness and beginning-of-life excess reactivi-ty under different numbers of rings of the fuel pins were studied when the assumed addi-tional shutdown margin was different .The results show that decreasing the number of rings and active fuel length would increase kef and decrease pressure drop across the core w hen the core equivalent diameter and total cross-sectional area of the coolant channel are unchanged .In order to increase additional shutdow n margin ,the absorber thickness should be increased while the beginning-of-life excess reactivity and power plant econo-my would decrease .%提出了一种适用于分布式发电系统的小型自然循环钠冷堆-AMTEC系统。通过对堆芯的临界计算和热工水力分析,研究了堆芯燃料装载量不变情况下,芯块半径、燃料棒长度和圈数对堆芯有效增殖因数 kef 、堆芯压降和传热的影响。同时分析了不同额外停堆裕量下,B4 C吸收层厚度和堆芯初始剩余反应性随燃料棒圈数的变化关系。计算结果表明:保持堆芯当量直径和冷却剂通道总截面积不变的情况下,减少燃料棒圈数和活性区长度不仅可增加 kef ,且能降低堆芯压降;为提高额外停堆裕量需增加吸收层厚度,但降低了堆芯初始剩余反应性,不利于电厂的经济性。

  14. 太阳能集热器的热流气体对砾石的蓄放热特性研究%Characteristics of heat storage and release of gravel layer in solar collectors by hot air natural circulation

    Institute of Scientific and Technical Information of China (English)

    张文基

    2005-01-01

    The thermal characteristics of heat storage and release of the gravel layer used in the solar collector in winter were analyzed. Air from the solar collector was expected to circulate through the gravel layer naturally without other energy consumption. The gravel layer consisted of river gravels with diameter from 50 mm to 100 mm. The temperature of the solar collector, gravel layer and cement mortar surface were measured respectively to analyze thermal characteristics of heat storage during daytime and heat release at night in the gravel layer. The horizontal and vertical heat characteristics of the gravel layer and cement mortar surface were analyzed. Results of the thermal characteristics of the gravel layer in the solar collector can be used as basic data for the thermal analysis of gravel layer.%太阳能的蓄放热特性的研究对清洁能源太阳能的开发和利用具有重要意义.该文利用冬季太阳能集热器的热流气体,对砾石的蓄放热特性进行了研究.以居民居住的标准房间(4 m×2.7 m)为依据进行了模拟;利用太阳能集热器的热能与直径为50~100 mm的砾石铺设成150 mm厚度的地下蓄热系统进行蓄热和放热试验,研究昼夜之间室内砾石的蓄热和放热特性;通过测试太阳能集热器的内部温度、砾石层内部及室内地表面的温度,研究了太阳能集热器的蓄热效率和转换效率,同时分析了蓄热层及室内地表面的热传递特性;为进一步开拓针对冬季寒冷地区太阳能蓄热型居民建筑物内部热环境方面的基础研究提供了科学的依据.

  15. Learning Circulant Sensing Kernels

    Science.gov (United States)

    2014-03-01

    learned dictionaries. Examples of analytic dictionaries include the discrete cosine basis, various wavelets bases , as well as tight frames. Some of them...Compressive sensing based high resolution channel estimation for OFDM system. To appear in IEEE Journal of Selected Topics in Signal Processing, Special...theoretical and computational properties to a (partial) circulant matrix of the same size, our discussions below are based exclusively on the circulant

  16. Monitoring the natural attenuation of petroleum in ground water at the former naval complex, Operable Unit A, Adak Island, Alaska, May and June 2003

    Science.gov (United States)

    Dinicola, R.S.; Simonds, F.W.; Defawe, Rose

    2005-01-01

    During May and June 2003, the U.S. Geological Survey installed monitoring wells and collected data to characterize the effectiveness of natural attenuation processes for remediating petroleum-contaminated ground water at Operable Unit A of the former Naval complex on Adak Island, Alaska. In addition, the evidence for petroleum biodegradation in ground water was evaluated at selected petroleum sites, plans for future natural attenuation monitoring were suggested for the selected petroleum sites, and the natural attenuation monitoring strategy for the Downtown area of Adak Island was reviewed and refinements were suggested. U.S. Geological Survey personnel measured water levels and collected ground-water samples from about 100 temporary boreholes and 50 monitoring wells. Most samples were analyzed on-site for concentrations of selected petroleum compounds and natural attenuation parameters such as dissolved oxygen, ferrous iron, and carbon dioxide. The U.S. Geological Survey evaluated the data on-site, selected new monitoring well locations, and installed, developed, and sampled 10 monitoring wells. The review and suggestions for the natural attenuation monitoring strategy focused on how to better achieve monitoring objectives specified in the Record of Decision for Adak Island petroleum sites. To achieve the monitoring objective of verifying that natural attenuation is occurring, the monitoring plans for each monitored natural attenuation site need to include sampling of at least one strategically placed well at the downgradient margin of the contaminant plume margin, preferably where contaminant concentrations are detectable but less than the cleanup level. Collection of natural attenuation parameter data and sampling background wells is no longer needed to achieve the monitoring objective of demonstrating the occurrence of natural attenuation. To achieve the objective of monitoring locations where chemical concentrations exceed specified cleanup levels, at least

  17. Two Types of Designs for On-Line Circulation Systems

    Directory of Open Access Journals (Sweden)

    Rob McGee

    1972-09-01

    Full Text Available On-line circulation systems divide into two types. One type contains records only for charged or otherwise absent items. The other contains a file of records for all titles or volumes in the library collection, regardless of their circulation status. This paper traces differences between the two types, examining different kinds of files and terminals, transaction evidence, the quality of bibliographic data, querying, and the possibility of functions outside circulation. Aspects of both operational and potential systems are considered.

  18. OPERATIONAL REMOTE SENSING SERVICES IN NORTH EASTERN REGION OF INDIA FOR NATURAL RESOURCES MANAGEMENT, EARLY WARNING FOR DISASTER RISK REDUCTION AND DISSEMINATION OF INFORMATION AND SERVICES

    Directory of Open Access Journals (Sweden)

    P. L. N. Raju

    2016-06-01

    Full Text Available North Eastern Region (NER of India comprising of eight states considered to be most unique and one of the most challenging regions to govern due to its unique physiographic condition, rich biodiversity, disaster prone and diverse socio-economic characteristics. Operational Remote Sensing services increased manifolds in the region with the establishment of North Eastern Space Applications Centre (NESAC in the year 2000. Since inception, NESAC has been providing remote sensing services in generating inventory, planning and developmental activities, and management of natural resources, disasters and dissemination of information and services through geo-web services for NER. The operational remote sensing services provided by NESAC can be broadly divided into three categories viz. natural resource planning and developmental services, disaster risk reduction and early warning services and information dissemination through geo-portal services. As a apart of natural resources planning and developmental services NESAC supports the state forest departments in preparing the forest working plans by providing geospatial inputs covering entire NER, identifying the suitable culturable wastelands for cultivation of silkworm food plants, mapping of natural resources such as land use/land cover, wastelands, land degradation etc. on temporal basis. In the area of disaster risk reduction, NESAC has initiated operational services for early warning and post disaster assessment inputs for flood early warning system (FLEWS using satellite remote sensing, numerical weather prediction, hydrological modeling etc.; forest fire alert system with actionable attribute information; Japanese Encephalitis Early Warning System (JEWS based on mosquito vector abundance, pig population and historical disease intensity and agriculture drought monitoring for the region. The large volumes of geo-spatial databases generated as part of operational services are made available to the

  19. Operational Remote Sensing Services in North Eastern Region of India for Natural Resources Management, Early Warning for Disaster Risk Reduction and Dissemination of Information and Services

    Science.gov (United States)

    Raju, P. L. N.; Sarma, K. K.; Barman, D.; Handique, B. K.; Chutia, D.; Kundu, S. S.; Das, R. Kr.; Chakraborty, K.; Das, R.; Goswami, J.; Das, P.; Devi, H. S.; Nongkynrih, J. M.; Bhusan, K.; Singh, M. S.; Singh, P. S.; Saikhom, V.; Goswami, C.; Pebam, R.; Borgohain, A.; Gogoi, R. B.; Singh, N. R.; Bharali, A.; Sarma, D.; Lyngdoh, R. B.; Mandal, P. P.; Chabukdhara, M.

    2016-06-01

    North Eastern Region (NER) of India comprising of eight states considered to be most unique and one of the most challenging regions to govern due to its unique physiographic condition, rich biodiversity, disaster prone and diverse socio-economic characteristics. Operational Remote Sensing services increased manifolds in the region with the establishment of North Eastern Space Applications Centre (NESAC) in the year 2000. Since inception, NESAC has been providing remote sensing services in generating inventory, planning and developmental activities, and management of natural resources, disasters and dissemination of information and services through geo-web services for NER. The operational remote sensing services provided by NESAC can be broadly divided into three categories viz. natural resource planning and developmental services, disaster risk reduction and early warning services and information dissemination through geo-portal services. As a apart of natural resources planning and developmental services NESAC supports the state forest departments in preparing the forest working plans by providing geospatial inputs covering entire NER, identifying the suitable culturable wastelands for cultivation of silkworm food plants, mapping of natural resources such as land use/land cover, wastelands, land degradation etc. on temporal basis. In the area of disaster risk reduction, NESAC has initiated operational services for early warning and post disaster assessment inputs for flood early warning system (FLEWS) using satellite remote sensing, numerical weather prediction, hydrological modeling etc.; forest fire alert system with actionable attribute information; Japanese Encephalitis Early Warning System (JEWS) based on mosquito vector abundance, pig population and historical disease intensity and agriculture drought monitoring for the region. The large volumes of geo-spatial databases generated as part of operational services are made available to the administrators and

  20. In-flight medical emergencies during airline operations: a survey of physicians on the incidence, nature, and available medical equipment.

    Science.gov (United States)

    Hinkelbein, Jochen; Neuhaus, Christopher; Böhm, Lennert; Kalina, Steffen; Braunecker, Stefan

    2017-01-01

    Data on the incidence of in-flight medical emergencies on-board civil aircraft are uncommon and rarely published. Such data could provide information regarding required medical equipment on-board aircraft and requisite training for cabin crew. The aim of the present study was to gather data on the incidences, nature, and medical equipment for in-flight medical emergencies by way of a survey of physician members of a German aerospace medical society. Using unipark.de (QuestBack GmbH, Cologne, Germany), an online survey was developed and used to gather specific information. Members of the German Society for Aviation and Space Medicine (Deutsche Gesellschaft für Luft- und Raumfahrtmedizin e.V.; DGLRM) were invited to participate in the survey during a 4-week period (21 March 2015 to 20 April 2015). Chi-square test was used for statistical analysis (pairline flights per year (median). Cardiovascular (40.0%) and neurological disorders (17.8%) were the most frequent diagnoses. The medical equipment (78.7%) provided was sufficient. An emergency diversion was undertaken in 10.6% of the cases. Although using a different method of data acquisition, this survey confirms previous data on the nature of emergencies and gives plausible numbers. Our data strongly argue for the establishment of a standardized database for recording the incidence and nature of in-flight medical emergencies. Such a database could inform on required medical equipment and cabin crew training.

  1. Evidence for the two-body nature of the E1 transition operator in the sdf-interacting boson model

    Energy Technology Data Exchange (ETDEWEB)

    Barfield, A.F.; Brentano, P. von; Dewald, A.; Zell, K.O.; Zamfir, N.V.; Bucurescu, D.; Ivascu, M.; Scholten, O.

    1989-01-01

    Two new a absolute transition rates are reported for the nucleus /sup 144/Sm following an (..cap alpha.., ..cap alpha..') Coulomb excitation study. They are B(E3;3/sup -/ -> 0/sup +/)=(38+-3)W.u. and B(E1;3/sup -/ -> 2/sup +/)=2.8+-0.4)x10/sup -3/W.u. This large E1 matrix element, along with the previously known B(E1;1/sup -/ -> 0/sup +/) value support the interpretation of the 1/sup -/ state in this nucleus as 2-phonon 2/sup +/x3/sup -/ excitation. In the frame of the IBM-1+f-boson model we show the need for a two-body term in the E1 transition operator. Estimates for the strenghts of the one and two-body parts of the E1 transition operator are obtained from these experimental data.

  2. The Evolving Nature of Warfare. Joint Center for Operational Analysis. Quarterly Bulletin, Volume 10, Issue 3, Fall 2008

    Science.gov (United States)

    2008-01-01

    particularly the “ art ” of strategic communication that COL Baker exhibited on this line of operation. Pakistan Earthquake: Unintended Consequences At...minds in some places (e.g., Kurdistan ) than in others (e.g., the Sunni Triangle). The relevance, however, is not in a comparison of the immensities... rocked by tropical breezes that could seem as cold as an arctic blast. They ate the same food: rice and black beans, supplemented by whatever fruit

  3. Linking supply chain operations' performance to the company's financial strategy: a case study of an Egyptian natural bottled water company

    OpenAIRE

    Elgazzar, S.; Tipi, Nicoleta S.; Hubbard, Nick J.; Leach, David Z.

    2011-01-01

    Over the last decade, supply chain management has become a recognized strategic tool\\ud to ensure customer satisfaction (Chopra and Meindl, 2004). Strategic supply chain\\ud management improves the way processes are done and hence improves long-term\\ud performance (Harrison and Van Hoek, 2005). Evaluating the performance of supply\\ud chain (SC) operations can contribute to redesigning business goals and strategies\\ud through assessing the current SC operations’ performance in order to identify...

  4. Conceptual models of the wind-driven and thermohaline circulation

    NARCIS (Netherlands)

    Drijfhout, S.S.; Marshall, D.P.; Dijkstra, H.A.

    2013-01-01

    Conceptual models are a vital tool for understanding the processes that maintain the global ocean circulation, both in nature and in complex numerical ocean models. In this chapter we provide a broad overview of our conceptual understanding of the wind-driven circulation, the thermohaline

  5. Conceptual models of the wind-driven and thermohaline circulation

    NARCIS (Netherlands)

    Drijfhout, S.S.; Marshall, D.P.; Dijkstra, H.A.

    2013-01-01

    Conceptual models are a vital tool for understanding the processes that maintain the global ocean circulation, both in nature and in complex numerical ocean models. In this chapter we provide a broad overview of our conceptual understanding of the wind-driven circulation, the thermohaline circulatio

  6. Conceptual models of the wind-driven and thermohaline circulation

    NARCIS (Netherlands)

    Drijfhout, S.S.; Marshall, D.P.; Dijkstra, H.A.

    2013-01-01

    Conceptual models are a vital tool for understanding the processes that maintain the global ocean circulation, both in nature and in complex numerical ocean models. In this chapter we provide a broad overview of our conceptual understanding of the wind-driven circulation, the thermohaline circulatio

  7. Gaussian Fibonacci Circulant Type Matrices

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available Circulant matrices have become important tools in solving integrable system, Hamiltonian structure, and integral equations. In this paper, we prove that Gaussian Fibonacci circulant type matrices are invertible matrices for n>2 and give the explicit determinants and the inverse matrices. Furthermore, the upper bounds for the spread on Gaussian Fibonacci circulant and left circulant matrices are presented, respectively.

  8. Heat transfer enhancement in a natural draft dry cooling tower under crosswind operation with heterogeneous water distribution

    Energy Technology Data Exchange (ETDEWEB)

    Goodarzi, Mohsen; Amooie, Hossein [Bu-Ali Sina Univ., Hamedan (Iran, Islamic Republic of). Dept. of Mechanical Engineering

    2016-04-15

    Crosswind significantly decreases cooling efficiency of a natural draft dry cooling tower. The possibility of improving cooling efficiency with heterogeneous water distribution within the cooling tower radiators under crosswind condition is analysed. A CFD approach was used to model the flow field and heat transfer phenomena within the cooling tower and airflow surrounding the cooling tower. A mathematical model was developed from various CFD results. Having used a trained Genetic Algorithm with the result of mathematical model, the best water distribution was found among the others. Remodeling the best water distribution with the CFD approach showed that the highest enhancement of the heat transfer compared to the usual uniform water distribution.

  9. Ocean circulation using altimetry

    Science.gov (United States)

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

    1991-01-01

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

  10. Impact assessment of the impact on nature values of the construction and operation of the repository for spent nuclear fuel at Forsmark; Konsekvensbedoemning av paaverkan paa naturvaerden av anlaeggande och drift av slutfoervar foer anvaent kaernbraensle i Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Allmer, Johan (Ekologigruppen AB, Stockholm (Sweden))

    2011-03-15

    Construction and operation of a repository at Soederviken in Forsmark, Oesthammar municipality means impact, effects and consequences for the environment. This report describes the natural conditions and natural values in Forsmark with particular focus on Soederviken. Furthermore, an assessment of consequences for the natural environment in the development and operation of a repository at Soederviken. Assessment of impacts from water activities are treated in a special report.

  11. In-flight medical emergencies during airline operations: a survey of physicians on the incidence, nature, and available medical equipment

    Directory of Open Access Journals (Sweden)

    Hinkelbein J

    2017-02-01

    Full Text Available Jochen Hinkelbein,1,2 Christopher Neuhaus,2,3 Lennert Böhm,1 Steffen Kalina,1 Stefan Braunecker1,2 1Department of Anaesthesiology and Intensive Care Medicine, University Hospital of Cologne, Cologne, 2Working group “Emergency Medicine and Air Rescue”, German Society for Aviation and Space Medicine (DGLRM, Munich, 3Department of Anesthesiology, Heidelberg University Hospital, Heidelberg, Germany Background: Data on the incidence of in-flight medical emergencies on-board civil aircraft are uncommon and rarely published. Such data could provide information regarding required medical equipment on-board aircraft and requisite training for cabin crew. The aim of the present study was to gather data on the incidences, nature, and medical equipment for in-flight medical emergencies by way of a survey of physician members of a German aerospace medical society.Materials and methods: Using unipark.de (QuestBack GmbH, Cologne, Germany, an online survey was developed and used to gather specific information. Members of the German Society for Aviation and Space Medicine (Deutsche Gesellschaft für Luft- und Raumfahrtmedizin e.V.; DGLRM were invited to participate in the survey during a 4-week period (21 March 2015 to 20 April 2015. Chi-square test was used for statistical analysis (p<0.05 was considered significant.Results: Altogether, 121 members of the society responded to the survey (n=335 sent out. Of the 121 respondents, n=54 (44.6% of the participants (89.9% male and 10.1% female; mean age, 54.1 years; n=121 were involved in at least one in-flight medical emergency. Demographic parameters in this survey were in concordance with the society members’ demographics. The mean duration of flights was 5.7 hours and the respondents performed 7.1 airline flights per year (median. Cardiovascular (40.0% and neurological disorders (17.8% were the most frequent diagnoses. The medical equipment (78.7% provided was sufficient. An emergency diversion was

  12. Circulant Double Coverings of a Circulant Graph of Valency Five

    Institute of Scientific and Technical Information of China (English)

    Rong Quan FENG; Jin Ho KWAK

    2007-01-01

    Enumerating the isomorphism classes of several types of graph covering projections is one of the central research topics in enumerative topological graph theory. A covering of G is called circulant if its covering graph is circulant. Recently, the authors [Discrete Math., 277, 73-85 (2004)]enumerated the isomorphism classes of circulant double coverings of a certain type, called a typicalcovering, and showed that no double covering of a circulant graph of valency three is circulant. Also, in [Graphs and Combinatorics, 21, 386-400 (2005)], the isomorphism classes of circulant double coverings of a circulant graph of valency four are enumerated. In this paper, the isomorphism classes of circulant double coverings of a circulant graph of valency five are enumerated.

  13. On the use of hydrate inhibitors for operating natural gas caverns; Zum Einsatz von Hydratinhibitoren beim Betrieb von Erdgasspeichern

    Energy Technology Data Exchange (ETDEWEB)

    Kleinitz, W.; Lissanon, S.J.; Luehn, H.G. [Preussag Energie GmbH, Lingen/Ems (Germany)

    1997-12-31

    One way to prevent gas hydrates in natural gas caverns is to use thermodynamic or kinetic inhibitors in a defined temperature / pressure range. The present contribution describes the temperature conditions prevailing in the tubing string. It also discusses bacterial processes around wells arising in association with methanol digesting bacteria, diethylene glycol digesting bacteria, and kinetic inhibitors. Further topics include inhibitor dosage and absorption drying. (MSK) [Deutsch] Zur Vermeidung von Gashydraten im Erdgasspeicherbereich werden thermodynamische oder kinetische Inhibitoren in einem definierten Temperatur/Druckbereich eingesetzt. Im Folgenden werden die Temperaturbedingungen im Steigrohrsystem erlaeutert. Ebenso werden die bakteriellen Vorgaenge im Bohrlochsbereich in folgenden Einzelheiten: Methanol-verwertenden Bakterien, Diethylenglykol-verwertende Bakterien sowie kinetische Inhibitoren diskutiert. Weitere Themenpunkte sind die Inhibitordosierung und die Adsorptionstrocknung.

  14. Kernels in circulant digraphs

    Directory of Open Access Journals (Sweden)

    R. Lakshmi

    2014-06-01

    Full Text Available A kernel $J$ of a digraph $D$ is an independent set of vertices of $D$ such that for every vertex $w,in,V(D,setminus,J$ there exists an arc from $w$ to a vertex in $J.$ In this paper, among other results, a characterization of $2$-regular circulant digraph having a kernel is obtained. This characterization is a partial solution to the following problem: Characterize circulant digraphs which have kernels; it appeared in the book {it Digraphs - theory, algorithms and applications}, Second Edition, Springer-Verlag, 2009, by J. Bang-Jensen and G. Gutin.

  15. Polarization and Dielectric Study of Methylammonium Lead Iodide Thin Film to Reveal its Nonferroelectric Nature under Solar Cell Operating Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hoque, Md Nadim Ferdous; Yang, Mengjin; Li, Zhen; Islam, Nazifah; Pan, Xuan; Zhu, Kai; Fan, Zhaoyang

    2016-07-08

    Researchers have debated whether methylammonium lead iodide (MAPbI3), with a perovskite crystal structure, is ferroelectric and therefore contributes to the current--voltage hysteresis commonly observed in hybrid perovskite solar cells (PSCs). We thoroughly investigated temperature-dependent polarization, dielectric, and impedance spectroscopies, and we found no evidence of ferroelectric effect in a MAPbI3 thin film at normal operating conditions. Therefore, the effect does not contribute to the hysteresis in PSCs, whereas the large component of ionic migration observed may play a critical role. Our temperature-based polarization and dielectric studies find that MAPbI3 exhibits different electrical behaviors below and above ca. 45 degrees C, suggesting a phase transition around this temperature. In particular, we report the activation energies of ionic migration for the two phases and temperature-dependent permittivity of MAPbI3. This study contributes to the understanding of the material properties and device performance of hybrid perovskites.

  16. The stripline circulator theory and practice

    CERN Document Server

    Helszajn, J

    2008-01-01

    Stripline circulator theory and applications from the world's foremost authority. The stripline junction circulator is a unique three-port non-reciprocal microwave junction used to connect a single antenna to both a transmitter and a receiver. Its operation relies on the interaction between an electron spin in a suitably magnetized insulator with an alternating radio frequency magnetic field. In its simplest form, it consists of a microwave planar gyromagnetic resonator symmetrically coupled by three transmission lines. This book explores the magnetic interaction involved in the stripline circ.

  17. Development of a 4K/80K multiple operating type of GM refrigeration system for the superconducting magnet in maglev use. Cooling characteristics of the nitrogen self-circulated cooling-type radiation shield plate; Fujoshiki tetsudoyo chodendojishaku no 4K/80K ryoyo GM reito sisutemu no kaihatsu. Chisso shizen junkanhoshiki netsu shirudo no reikyaku tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Nakao, Hiroyuki; Takahashi, Masahiko; Sanada, Yoshinao; Yamashita, Tomohiro; Yamaji, Mutsuhiko [Toshiba Corp., Tokyo (Japan); Terai, Motoaki [Central Japan Railway Corp., Tokyo (Japan); Igarashi, Motohiro; Yamaguchi, Mitsugu [Niigata Unviersity, Niigata (Japan)

    1999-02-25

    An onboard refrigeration system is one of the most important components in the superconducting magnetically levitated system (Maglev system). In the superconducting magnet, liquid helium and nitrogen are used to cool the superconducting coils and the radiation shields. At the Yamanashi Maglev Test Line, the operation of the superconducting magnet without a supplement of liquid helium has been achieved by the onboard 4 K Gifford-McMahon/Joule-Thomson (GM/JT) refrigerators- . As for the liquid nitrogen, it is supplied to the radiation shields periodically. Our final target for an onboard refrigeration system for commercial use is to operate magnets with no supplementation of cryogen. That is the operations of magnets should not depend on a helium liquefaction plant or a liquid nitrogen supplying system in the train depot, except for occasions of the magnet's precooling or when the vehicle is being overhauled. To meet these requirements, we have been developing a new type of onboard GM refrigeration (GM refrigerator application) system that features a combination of a 4K/80K multiple-operating type of GM refrigerator and a self-circulated cooling-type radiation shield. The nitrogen self-circulated cooling-type radiation shield plate was demonstrated by using the radiation shield plate mock-up. (author)

  18. Calcium copper-titanate thin film growth: tailoring of the operational conditions through nanocharacterization and substrate nature effects.

    Science.gov (United States)

    Lo Nigro, Raffaella; Toro, Roberta G; Malandrino, Graziella; Fragalà, Ignazio L; Losurdo, Maria; Giangregorio, Michelaria M; Bruno, Giovanni; Raineri, Vito; Fiorenza, Patrick

    2006-09-07

    A novel approach based on a molten multicomponent precursor source has been applied for the MOCVD fabrication of high-quality CaCu(3)Ti(4)O(12) (CCTO) thin films on various substrates. The adopted in situ strategy involves a molten mixture consisting of Ca(hfa)(2).tetraglyme, Ti(tmhd)(2)(O-iPr)(2), and Cu(tmhd)(2) [Hhfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedione; tetraglyme = 2,5,8,11,14-pentaoxapentadecane; Htmhd = 2,2,6,6-tetramethyl-3,5-heptandione; O-iPr = isopropoxide] precursors. Film structural and morphological characterizations have been carried out by several techniques [X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM)], and in particular the energy filtered TEM mapping and X-ray energy dispersive (EDX) analysis in TEM mode provided a suitable correlation between nanostructural properties of CCTO films and deposition conditions and/or the substrate nature. Correlation between the nanostructure and optical/dielectric properties has been investigated exploiting spectroscopic ellipsometry.

  19. Performance evaluation of a fuel cell with NiO-YSV anode operating with natural gas; Avaliacao do desempenho de uma celula a combustivel com anodo de NiO YSZ operando com gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Nobrega, Shayenne Diniz da; Vasconcelos, Carmel Suzarte Ayres; Lima, Luiz Rogerio Pinho de Andrade [Universidade Federal da Bahia (UFBa), Salvador, BA (Brazil). Escola Politecnica. Dept. de Ciencia e Tecnologia dos Materiais]. E-mail: shayennedn@yahoo.com.br

    2008-07-01

    Fuel cell is an electrochemical device that converts the chemical energy into electric energy. The natural gas, for its proven improvement in the income of the equipment in relation to other energy ones, has been very used to feed the solid oxide fuel cell (SOFC) in the generation of electric power. Ceramics of Yttria-stabilized zirconia had been used as electrolyte and when supported with nickel oxide they act as anode in the solid oxide fuel cell, due to raised ionic conductivity that these materials present in high temperatures, while lanthanum with strontium and manganite are used as cathode. In the composition of the anode, the concentration of Ni O, acting as catalytic in the YSZ confers high electric conductivity and high electrochemical activity of the reactions, providing the internal reform in the SOFC. In this work, the solid oxide fuel cell, formed by Yttria- stabilized zirconia, nickel oxide, and lanthanum with strontium and manganite were tested in the reform had been prepared samples of electrode/electrolyte for use in SOFC of the natural gas in the presence of low water text, similar condition to the operation of the SOFC, operating in temperatures range from 700 to 800 deg C. This cell also was characterized using the impedance spectroscopy technique. These results allowed the development of components of the current versus voltage. (author)

  20. A 12 GHz broadband latching circulator

    Science.gov (United States)

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

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

  1. Kinetic inhibition of natural gas hydrates in offshore drilling, production, and processing operations. Annual report, January 1--December 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1992-12-31

    Natural gas hydrates are solid crystalline compounds which form when molecules smaller than n-butane contact molecules of water at elevated pressures and reduced temperatures, both above and below the ice point. Because these crystalline compounds plug flow channels, they are undesirable. In this project the authors proposed an alternate approach of controlling hydrate formation by preventing hydrate growth into a sizeable mass which could block a flow channel. The authors call this new technique kinetic inhibition, because while it allows the system to exist in the hydrate domain, it prevents the kinetic agglomeration of small hydrate crystals to the point of pluggage of a flow channel. In order to investigate the kinetic means of inhibiting hydrate formation, they held two consortium meetings, on June 1, 1990 and on August 31, 1990. At subsequent meetings, the authors determined the following four stages of the project, necessary to reach the goal of determining a new hydrate field inhibitor: (1) a rapid screening method was to be determined for testing the hydrate kinetic formation period of many surfactants and polymer candidates (both individually and combined), the present report presents the success of two screening apparatuses: a multi-reactor apparatus which is capable of rapid, high volume screening, and the backup screening method--a viscometer for testing with gas at high pressure; (2) the construction of two high, constant pressure cells were to experimentally confirm the success of the chemicals in the rapid screening apparatus; (3) in the third phase of the work, Exxon volunteered to evaluate the performance of the best chemicals from the previous two stages in their 4 inch I.D. Multiphase flow loop in Houston; (4) in the final phase of the work, the intention was to take the successful kinetic inhibition chemicals from the previous three stages and then test them in the field in gathering lines and wells from member companies.

  2. Observations of Langmuir Circulation From FLIP

    Science.gov (United States)

    Smith, J. A.

    2002-12-01

    Langmuir circulation has significance across the marine disciplines. Enhanced deepening and inhibited re-stratification can alter the surface temperature and hence net air-sea exchanges. Organization of bubbles into windrows introduces dramatic sound speed variability and also affects air/sea gas fluxes. Organization of seaweed and plankton affects marine life, including pelagic fisheries. Finally, dispersal by Langmuir circulation is a major component in models for oil-spill tracking and for search-and-rescue operations. To get an adequate picture of the forcing and response of Langmuir circulation (and the wind-mixed layer in general), the observations needed include windstress, directional waves, wave breaking, heat and moisture fluxes, stratification (temperature and salinity profiles), velocity profiles across the mixed layer and thermocline, spacing and orientation of windrows, and a measure of the strength of the circulation (e.g., surface rms velocities). These measurements span both the air/sea interface and the thermocline, and must be maintained continuously for many days to span storms and daily, tidal, and inertial cycles. In addition, the total power requirements exceed that comfortably supplied by batteries or local generation by wind or solar energy. It appears that FLIP is uniquely qualified as a platform from which the required range of measurements may all be made. Findings concerning the evolution and dynamics of Langmuir circulation that were facilitated by FLIP are reviewed and summarized, with emphasis on observations from 1990, 1995, and 2002.

  3. Nucla circulating atmospheric fluidized bed demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-31

    During the fourth quarter of 1990, steady-state performance testing at the Nucla Circulating Fluidized Bed (CFB) resumed under sponsorship of the US Department of Energy. Co-sponsorship of the Demonstration Test Program by the Electric Power Research Institute (EPRI) was completed on June 15, 1990. From October through December, 1990, Colorado-Ute Electric Association (CUEA) completed a total of 23 steady-state performance tests, 4 dynamic tests, and set operating records during November and December as the result of improved unit operating reliability. Highlight events and achievements during this period of operation are presented.

  4. State of the Art Report for a Bearing for VHTR Helium Circulator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Seon; Song, Kee Nam; Kim, Yong Wan; Lee, Won Jae

    2008-10-15

    A helium circulator in a VHTR(Very High Temperature gas-cooled Reactor) plays a core role which translates thermal energy at high temperature from a nuclear core to a steam generator. Helium as a operating coolant circulates a primary circuit in high temperature and high pressure state, and controls thermal output of a nuclear core by controlling flow rate. A helium circulator is the only rotating machinery in a VHTR, and its reliability should be guaranteed for reliable operation of a reactor and stable production of hydrogen. Generally a main helium circulator is installed on the top of a steam generator vessel, and helium is circulated only by a main helium circulator in a normal operation state. An auxiliary or shutdown circulator is installed at the bottom of a reactor vessel, and it is an auxiliary circulator for shutting down a reactor in case of refueling or accelerating cooling down in case of fast cooling. Since a rotating shaft of a helium circulator is supported by bearings, bearings are the important machine elements which determines reliability of a helium circulator and a nuclear reactor. Various types of support bearings have been developed and applied for circulator bearings since 1960s, and it is still developing for developing VHTRs. So it is necessary to review and analyze the current technical state of helium circulator support bearings to develop bearings for Koran developing VHTR helium circulator.

  5. Natural Propositions

    DEFF Research Database (Denmark)

    Stjernfelt, Frederik

    Preface -- Introduction -- The generality of signs -- Dicisigns -- Some consequences of the dicisign doctrine -- Dicisigns and cognition -- Natural propositions--the evolution of semiotic self-control -- Dicisigns beyond language -- Operational and optimal iconicity in Peirce's diagrammatology...

  6. Natural Propositions

    DEFF Research Database (Denmark)

    Stjernfelt, Frederik

    Preface -- Introduction -- The generality of signs -- Dicisigns -- Some consequences of the dicisign doctrine -- Dicisigns and cognition -- Natural propositions--the evolution of semiotic self-control -- Dicisigns beyond language -- Operational and optimal iconicity in Peirce's diagrammatology...

  7. Ocean circulation studies

    Science.gov (United States)

    Koblinsky, C. J.

    1984-01-01

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

  8. The fetal circulation.

    Science.gov (United States)

    Kiserud, Torvid; Acharya, Ganesh

    2004-12-30

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

  9. 循环水泵前池水位降低对汽轮机冷端系统运行性能影响分析%Influence Analysis of Circulating Water Pump Forebay Water Lowering on the Operating Performance of Steam Turbine Cold-end System

    Institute of Scientific and Technical Information of China (English)

    田思来; 程东涛; 居文平

    2016-01-01

    Water lowering of the power station circulating water pump forebay compared to local water level influences the safety and economy of the steam turbine cold-end system.Through quantitative analysis and qualitative analysis ,the analysis of impact of water lowering of the circulating water pump forebay on the economic performance of the steam turbine cold -end system,clearly put forward decision criteria for operating safety of the steam turbine cold-end system.A set of simple and practical calculation method is developed , applied to the quantitative analysis on the problems existing in the circulating water system,at the same time provides guidance advice for the work of design and selection of circulating water system of same type.%电站循环水泵前池水位相对水源地水位下降,对汽轮机冷端系统安全性和经济性运行产生重要影响。通过定量分析和定性分析相结合,分析计算循环水泵前池水位下降对汽轮机冷端系统运行经济性的影响量,明确了对汽轮机冷端系统运行安全性影响的判定标准。形成了一套简便、实用的分析计算方法,对循环水取水系统存在的问题进行量化分析,同时为同类型循环水取水系统的设计选型工作提供了指导建议。

  10. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    1992-02-01

    The objective of this DOE Cooperative Agreement is to conduct a cost-shared clean coal technology project to demonstrate the feasibility of circulating fluidized bed combustion technology and to evaluate economic, environmental, and operational benefits of CFB steam generators on a utility scale. At the conclusion of the Phase 2 program, testing related to satisfying these objectives was completed. Data analysis and reporting are scheduled for completion by October 1991. (VC)

  11. Cluster Dynamics in a Circulating Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-11-01

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

  12. Modelled Circulation In Storfjorden

    Science.gov (United States)

    Skogseth, R.; Asplin, L.

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

  13. Uncertainty in particle number modal analysis during transient operation of compressed natural gas, diesel, and trap-equipped diesel transit buses.

    Science.gov (United States)

    Holmén, Britt A; Qu, Yingge

    2004-04-15

    The relationships between transient vehicle operation and ultrafine particle emissions are not well-known, especially for low-emission alternative bus technologies such as compressed natural gas (CNG) and diesel buses equipped with particulate filters/traps (TRAP). In this study, real-time particle number concentrations measured on a nominal 5 s average basis using an electrical low pressure impactor (ELPI) for these two bus technologies are compared to that of a baseline catalyst-equipped diesel bus operated on ultralow sulfur fuel (BASE) using dynamometer testing. Particle emissions were consistently 2 orders of magnitude lower for the CNG and TRAP compared to BASE on all driving cycles. Time-resolved total particle numbers were examined in terms of sampling factors identified as affecting the ability of ELPI to quantify the particulate matter number emissions for low-emitting vehicles such as CNG and TRAP as a function of vehicle driving mode. Key factors were instrument sensitivity and dilution ratio, alignment of particle and vehicle operating data, sampling train background particles, and cycle-to-cycle variability due to vehicle, engine, after-treatment, or driver behavior. In-cycle variability on the central business district (CBD) cycle was highest for the TRAP configuration, but this could not be attributed to the ELPI sensitivity issues observed for TRAP-IDLE measurements. Elevated TRAP emissions coincided with low exhaust temperature, suggesting on-road real-world particulate filter performance can be evaluated by monitoring exhaust temperature. Nonunique particle emission maps indicate that measures other than vehicle speed and acceleration are necessary to model disaggregated real-time particle emissions. Further testing on a wide variety of test cycles is needed to evaluate the relative importance of the time history of vehicle operation and the hysteresis of the sampling train/dilution tunnel on ultrafine particle emissions. Future studies should

  14. Environmental health research recommendations from the Inter-Environmental Health Sciences Core Center Working Group on unconventional natural gas drilling operations.

    Science.gov (United States)

    Penning, Trevor M; Breysse, Patrick N; Gray, Kathleen; Howarth, Marilyn; Yan, Beizhan

    2014-11-01

    Unconventional natural gas drilling operations (UNGDO) (which include hydraulic fracturing and horizontal drilling) supply an energy source that is potentially cleaner than liquid or solid fossil fuels and may provide a route to energy independence. However, significant concerns have arisen due to the lack of research on the public health impact of UNGDO. Environmental Health Sciences Core Centers (EHSCCs), funded by the National Institute of Environmental Health Sciences (NIEHS), formed a working group to review the literature on the potential public health impact of UNGDO and to make recommendations for needed research. The Inter-EHSCC Working Group concluded that a potential for water and air pollution exists that might endanger public health, and that the social fabric of communities could be impacted by the rapid emergence of drilling operations. The working group recommends research to inform how potential risks could be mitigated. Research on exposure and health outcomes related to UNGDO is urgently needed, and community engagement is essential in the design of such studies.

  15. Cereral Circulation in Preeclampsia

    Directory of Open Access Journals (Sweden)

    A. A. Ivshin

    2008-01-01

    Full Text Available Objective: to evaluate the possibilities of using transcranial Doppler study in pregnant women and pueperas with preeclamp-sia. Subjects and methods. Two hundred and thirty-two pregnant women diagnosed as having varying preeclampsia were prospectively studied. A comparison group comprised 90 apparently healthy women in the third trimester of pregnancy. All the respondents underwent transcranial duplex scanning of the medial cerebral artery with the linear velocity values being determined. A number of the values reflecting the level of perfusion and intracranial pressures, hydrodynamic resistance in the system, cerebrovascular responsiveness and the state of the vascular wall were calculated. Correlation analysis was made between the parameters of cerebral circulation and the severity of preeclampsia, proteinuria, the severity of hydrops, and the parameters of central and peripheral hemodynamics. Results. The findings suggest that there is impaired cerebral perfusion in pregnant women and puerperas with varying preeclampsia, the severity of cerebral circulatory disorders being in proportion with that of preeclampsia. There is a close correlation between cerebral circulation and the individual criteria determining the severity of preeclampsia. The linear values of the Doppler spectrum, namely linear flow characteristics, are prognos-tically most significant. Conclusion. The introduction of transcranial Doppler study into obstetric care has permitted the authors not only to study cerebral circulatory disorders in healthy and pregnant women and puerperas with preeclampia in detail, but also to establish a number of highly significant prognostic criteria for the severity of this life-threatening complication of gestation. The results of transcranial Doppler study assist practitioners in timely and accurately solving the problems in the diagnosis of preeclampsia and in evaluating its severity. Cerebral circulatory values may be successfully used to

  16. World Ocean Circulation Experiment

    Science.gov (United States)

    Clarke, R. Allyn

    1992-01-01

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

  17. Resolvability in Circulant Graphs

    Institute of Scientific and Technical Information of China (English)

    Muhammad SALMAN; Imran JAVAID; Muhammad Anwar CHAUDHRY

    2012-01-01

    A set W of the vertices of a connected graph G is called a resolving set for G if for every two distinct vertices u,v ∈ V(G) there is a vertex w ∈ W such that d(u,w) ≠ d(v,w).A resolving set of minimum cardinality is called a metric basis for G and the number of vertices in a metric basis is called the metric dimension of G,denoted by dim(G).For a vertex u of G and a subset S of V(G),the distance between u and S is the number mins∈s d(u,s).A k-partition H ={S1,S2,...,Sk} of V(G) is called a resolving partition if for every two distinct vertices u,v ∈ V(G) there is a set Si in Π such that d(u,Si) ≠ d(v,Si).The minimum k for which there is a resolving k-partition of V(G) is called the partition dimension of G,denoted by pd(G).The circulant graph is a graph with vertex set Zn,an additive group ofintegers modulo n,and two vertices labeled i and j adjacent if and only if i - j (mod n) ∈ C,where C C Zn has the property that C =-C and 0(∈) C.The circulant graph is denoted by Xn,△ where A =|C|.In this paper,we study the metric dimension of a family of circulant graphs Xn,3 with connection set C ={1,-n/2,n - 1} and prove that dim(Xn,3) is independent of choice of n by showing that 3 for all n =0 (mod 4),dim(X,n,3) ={ 4 for all n =2 (mod 4).We also study the partition dimension of a family of circulant graphs Xn,4 with connection set C ={±1,±2} and prove that pd(Xn,4) is independent of choice of n and show that pd(X5,4) =5 and 3 forall odd n≥9,pd(Xn,4) ={ 4 for all even n ≥ 6 and n =7.

  18. Preconceptual design of the new production reactor circulator test facility

    Energy Technology Data Exchange (ETDEWEB)

    Thurston, G.

    1990-06-01

    This report presents the results of a study of a new circulator test facility for the New Production Reactor Modular High-Temperature Gas-Cooled Reactor. The report addresses the preconceptual design of a stand-alone test facility with all the required equipment to test the Main Circulator/shutoff valve and Shutdown Cooling Circulator/shutoff valve. Each type of circulator will be tested in its own full flow, full power helium test loop. Testing will cover the entire operating range of each unit. The loop will include a test vessel, in which the circulator/valve will be mounted, and external piping. The external flow piping will include a throttle valve, flowmeter, and heat exchanger. Subsystems will include helium handling, helium purification, and cooling water. A computer-based data acquisition and control system will be provided. The estimated costs for the design and construction of this facility are included. 2 refs., 15 figs.

  19. Effect analysis of quality control circle activity improving hand-washing compliance of circulating nurses in operating room%品管圈活动对提高手术室巡回护士洗手依从性效果分析

    Institute of Scientific and Technical Information of China (English)

    万美萍; 吴明琴; 罗媛榕

    2015-01-01

    目的:分析影响护理人员手卫生执行的相关因素,探究品管圈活动对于提高手术室巡回护士洗手依从性及综合素质的效果。方法选取我院12名手术室巡回护士为研究对象,采用品管圈的管理方式对其进行护理干预,比较不同时段内护理人员的洗手依从性及综合素质。结果干预实施前及干预1周后、干预2周后巡回护士的总体洗手执行率分别为72%、80.0%、73.3%,总体洗手执行率在干预1周后显著上升。2周后又回落到了干预前相似水平,干预实施前及干预1周后、干预2周后巡回护士的平均素质得分分别为(52.4±4.6)、(68.0±6.4)、(83.6±8.5),差异均有统计学意义(P<0.01)。结论品管圈活动可以有效提高手术室巡回护士的综合素质,在短期内也可迅速提升其洗手的依从性,但由于品管圈活动缺乏长期监督管理的环境,巡回护士其交接安置患者洗手率会严重回落,直接导致总体洗手依从性会再次回落。%ObjectiveTo analyze related factors of hand hygiene implementation and to explore effect of quality control circle activity on improving hand-washing compliance and comprehensive quality of circulating nurses in operating room.Methods12 circulating nurses of operating room in our hospital were selected as research objects and they were received nursing intervention by management method of quality control circle. Hand-washing compliance and comprehensive quality of nursing staff during different periods were compared.Results Total hand-washing implementation rates before intervention, 1 week after intervention and 2 weeks after intervention of circulating nurses were 72%, 80.0% and 73.3% respectively. Total hand-washing implementation rate of 1 week after intervention was significantly increased while total hand-washing implementation rate of weeks after intervention was the same as that before intervention. Average quality

  20. Walker circulation in a transient climate

    Science.gov (United States)

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

    2016-04-01

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

  1. Circulation of Stars

    Science.gov (United States)

    Boitani, P.

    2016-01-01

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

  2. North Atlantic Circulation

    Science.gov (United States)

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

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

  3. 黑龙江省绿色农产品流通渠道的构建与运营%The Establishment and Operation of Circulation Channel of Green Agriculture Products in Heilongjiang

    Institute of Scientific and Technical Information of China (English)

    魏静; 吕杨

    2015-01-01

    With an increasing demand of green agricultural products, to establish an exclusive channel for the circulation of the products is in urgent need as it is difficult for consumers to identify the products and the agricultural product market has been in disorder for a long time. In Heilongjiang province, to control the circulation channels, green agriculture products will be sold directly in chain stores, which sell green products only. The chain stores will take online or telephone orders with the help of website promotion. Meanwhile, the stores will look for and help build large-sized green product processing bases. The green consumption habit will be shaped by the influence of creation and environmental protection philosophy of college students.%当前,消费者对绿色农产品消费需求越来越大,但消费者对绿色农产品辨认难度很大,再加上长期以来农产品市场的无序,急需构建一个专业的绿色农产品流通专控渠道。对于绿色流通渠道的专控,黑龙江省准备采用直营的方式,只销售绿色农产品,禁止非绿色农产品的进入。以直营店的形式面向消费者,配合网页介绍,并接受网上和电话预定。在直营店背后,寻找并培养具有规模的绿色农产品生产加工基地。以销售影响上一级产业链,以大学生创业者的创新、环保理念,逐渐影响社会形成绿色消费的风气。

  4. An Analysis of the Importance of the Circulation Industry in the Western Ethnic Region and Its Development Strategy

    Institute of Scientific and Technical Information of China (English)

    LI Rongqing

    2013-01-01

    will be coordination , distribution of responsi-bilities, and complementary advantages between the western region and the eastern region , and e-ven the world . By combining the commercial skills, commodities, information, capital, and technical personnel of the eastern region and other countries with the western region , there will be a close co -operation between the two sides .Ac-cordingly, the economic gap between the western region and eastern region will be reduced , and close economic relations between the two regions will be established.As a result, the two regions will reach a common development and prosperity , which will definitely contribute to the national har-mony and stability . The development of circulation industry in the western ethnic region still lags behind .In terms of per capita social total retail sales , the western re-gion lags far behind the east region .No matter if we judge from the potential competitive power or the real competitive power , the provinces in the western region are listed last in the country , and they lack competitive power in the circulation in-dustry.The reasons are as follows: first, the poor natural conditions of the region objectively prevent development of the circulation industry .If seen from the location of the region , the living condi-tions surrounding the western ethnic region are not good , and natural disasters frequently occur .The poor natural conditions objectively increase the dif-ficulties in constructing circulation industry facili-ties, and thus , influence the development of the circulation industry .Second , the social system is growing slowly , and, for a long time it did not pay attention to the basic position of the circulation in-dustry .Enterprises and institutions on various lev-els do not notice the “pull” role of commercial de-velopment for local economic development , and they have not yet built up a framework for taking the circulation industry as a leading industry . Hence, the

  5. Global ocean circulation by altimetry

    Science.gov (United States)

    Wunsch, Carl; Haidvogel, D.

    1991-01-01

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

  6. Percutaneous interventions in Fontan circulation

    Directory of Open Access Journals (Sweden)

    Eduardo Franco

    2015-09-01

    Conclusions: Interventional catheterization procedures are often necessary to reach and maintain the fragile Fontan circulation, mainly in patients with right morphology systemic ventricles and fenestrated Fontan conduits.

  7. Lost circulation technology development status

    Energy Technology Data Exchange (ETDEWEB)

    Glowka, D.A.; Schafer, D.M.; Loeppke, G.E.; Scott, D.D.; Wernig, M.D.; Wright, E.K.

    1992-07-01

    Lost circulation is the loss of drilling fluid from the wellbore to fractures or pores in the rock formation. In geothermal drilling, lost circulation is often a serious problem that contributes greatly to the cost of the average geothermal well. The Lost Circulation Technology Development Program is sponsored at Sandia National Laboratories by the US Department of Energy. The goal of the program is to reduce lost circulation costs by 30--50% through the development of mitigation and characterization technology. This paper describes the technical progress made in this program during the period April 1991--March 1992. 8 refs.

  8. Trypanosoma cruzi: circulating antigens

    Directory of Open Access Journals (Sweden)

    V. Bongertz

    1981-03-01

    Full Text Available Circulating antigens were detected in sera of mice experimentally infected with a high close of Trypanosoma cruzi by reaction with sera from chronically infected mice. The immunodiffusion reaction between homologous acute and chronic sera produced four precipitation lines. By reaction with chronic mouse serum, circulating antingens were detected in sera from heavily infected hamsters, dogs, rabbits and in sera from chagasic patients. A reaction was also found in urine from acutely infected mice and dogs. Trypanosoma cruzi exoantigen was detected in trypanosome culture medium and in the supernatant of infected cell cultures. Attempts to isolate the antigens are described.Antígenos circulantes foram detectados em soros de camundongos infectados experimentalmente com elevadas doses de Trypanosoma cruzi pela reação com soros obtidos de camundongos em fase crônica de infecção. A reação de imunodifusão entre soros homólogos agudo e crônico produziu quatro linhas de precipitação. Por reação com soro crônico de camundongo antígenos circulantes foram detectados em soros de crícetos, cães e coelhos infectados com doses elevadas de Trypanosoma cruzi e em soros de pacientes chagásicos. Uma reação foi também observada com urina de camundongos e cães infectados de forma aguda. Exoantígeno de Trypanosoma cruzi foi detectado em meio de cultura de tripanosomas e em sobrenadantes de culturas de células infectadas. Tentativas de isolamento dos antigenos são descritas.

  9. The incidence and nature of adverse events during pediatric sedation/anesthesia with propofol for procedures outside the operating room: a report from the Pediatric Sedation Research Consortium.

    Science.gov (United States)

    Cravero, Joseph P; Beach, Michael L; Blike, George T; Gallagher, Susan M; Hertzog, James H

    2009-03-01

    We used a large database of prospectively collected data on pediatric sedation/anesthesia outside the operating room provided by a wide range of pediatric specialists to delineate the nature and frequency of adverse events associated with propofol-based sedation/anesthesia care. Data were collected by the Pediatric Sedation Research Consortium, a collaborative group of institutions dedicated to improving sedation/anesthesia care for children internationally. Members prospectively enrolled consecutive patients receiving sedation or sedation/anesthesia for procedures. The primary inclusion criterion was the need for some form of sedation/anesthesia to perform a diagnostic or therapeutic procedure outside the operating room. There were no exclusion criteria. Data on demographics, primary illness, coexisting illness, procedure performed, medications used, procedure and recovery times, medication doses outcomes of anesthesia, airway interventions and adverse events were collected and reported using web-based data collection tool. For this study, we evaluated all instances where propofol was used as the primary drug in the sedation/anesthesia technique. Thirty-seven locations submitted data on 49,836 propofol sedation/anesthesia encounters during the study period from July 1, 2004 until September 1, 2007. There were no deaths. Cardiopulmonary resuscitation was required twice. Aspiration during sedation/anesthesia occurred four times. Less serious events were more common with O(2) desaturation below 90% for more than 30 s, occurring 154 times per 10,000 sedation/anesthesia administrations. Central apnea or airway obstruction occurred 575 times per 10,000 sedation/anesthesia administrations. Stridor, laryngospasm, excessive secretions, and vomiting had frequencies of 50, 96, 341, and 49 per 10,000 encounters, respectively. Unexpected admissions (increases in levels of care required) occurred at a rate of 7.1 per 10,000 encounters. In an unadjusted analysis, the rate of

  10. Measurements of heat transfer and operating experience at the Wolfsburg power plant with a circulating fluidized bed furnace; Messungen zum Waermeuebergang und Betriebserfahrungen im Kraftwerk Wolfsburg mit zirkulierender Wirbelschichtfeuerung

    Energy Technology Data Exchange (ETDEWEB)

    Bluemel, W. [VW Kraftwerke GmbH, Wolfsburg (Germany); Kaeferstein, P. [VW Kraftwerke GmbH, Wolfsburg (Germany); Rummel, A.. [Technische Univ. Magdeburg (Germany). Inst. fuer Thermische Apparate- und Umwelttechnik (Germany); Moerl, P. [Technische Univ. Magdeburg (Germany). Inst. fuer Thermische Apparate- und Umwelttechnik (Germany)

    1992-12-31

    In order to obtain a deeper insight into the configurations developing upon the combustion of hard coal in an industrial circulating fluidized bed, an extensive process analysis was made. The determination of the heat transfer coefficient in the entire range of the steam generator was an essential part of this investigation. The exact calculation of the evaporator turns out to be difficult, as this part is distributed on the furnace, the second pass heating surfaces and the external heat exchanger. Within the scope of the lecture, the determination method as well as its results is presented. Furthermore, a report is made on latest methods for the improvement of the fuel burn-out and on the reduction of the lime consumption, which have resulted from experiments with the modification of combustion-technological parameters such as air ratio, combustion chamber temperatures for various types of coal. To conclude with, a computer-aided databank for the evaluation of various types of coals is being presented. (orig.) [Deutsch] Zum Zwecke einer tieferen Einsicht in die Zusammenhaenge bei der Verbrennung von Steinkohle in einer industriell betriebenen zirkulierenden Wirbelschicht wurde eine umfassende Prozessanalyse durchgefuehrt. Ein wesentlicher Bestandteil dieser Untersuchung war die Ermittlung des Waermedurchgangskoeffizienten im gesamten Bereich des Dampferzeugers. Da sich z.B. der Verdampferteil sowohl in der Brennkammer, in den nachschaltheizflaechen als auch im Fliessbettkuehler befindet, gestaltet sich die exakte Berechnung als sehr kompliziert. Im Rahmen dieses Vortrages werden sowohl die Methodik der Ermittlung als auch deren Ergebnisse vorgestellt. Ausserdem wird sowohl ueber neuere Ansaetze zur Verbesserung des Ausbrandes als auch ueber die Reduzierung des Kalkverbrauches berichtet, die sich aus Ergebnissen von Versuchen unter Aenderung von feuerungstechnischen Parametern wie Luftverhaeltnis, Brennkammertemperaturen und auch verschiedener Kohlen ergeben haben

  11. 体外循环下机器人心脏手术的手术室管理%Management of the operating room for the robotic cardiac surgery with extracorporeal circulation

    Institute of Scientific and Technical Information of China (English)

    赵悦; 李丽霞; 李密影

    2011-01-01

    Objective To observe 231 cases of minimally robotic on - pump cardiac surgery and summarize the management experience from these operations. Methods From January 2007 to April 2011, 231 cases of minimally invasive on - pump cardiac surgery had been accomplished by " Da Vinci S" robotic operation system in Cardiovascular Surgery Department of the PLA General Hospital. Results 231 cases of minimally invasive robotic on - pump cardiac surgery were successfully finished without intubation failure and no case was converted to sternotomy. Conclusion Reasonable layout of the operation room, tacit operative cooperation and comprehensive master of the " Da Vinci S" robotic operation system are the key factors to make sure that the cardiac surgery are going smoothly.%目的 观察231例体外循环下微创机器人心脏手术,总结其术中管理经验.方法 2007年1月至2011年4月,我院心脏外科使用"达芬奇S"机器人手术系统完成体外循环下微创手术231例.回顾分析术前手术室布局、体外循环下的手术配合及术中的管理方法.结果 成功地完成了231例体外循环下全机器人心脏手术,无术中插管失败,中转开胸.结论 合理的手术室布局,熟练的手术配合和对机器人系统的全面掌握是保证机器人心脏手术顺利进行的关键.

  12. Sino-Danish Brain Circulation

    DEFF Research Database (Denmark)

    Bertelsen, Rasmus Gjedssø; Du, Xiangyun; Søndergaard, Morten Karnøe

    2014-01-01

    China is faced with urgent needs to develop an economically and environmentally sustainable economy based on innovation and knowledge. Brain circulation and research and business investments from the outside are central for this development. Sino-American brain circulation and research...... and investment by overseas researchers and entrepreneurs are well described. In that case, the US is the center of global R&D and S&T. However, the brain circulation and research and investments between a small open Scandinavian economy, such as Denmark, and the huge developing economy of China are not well...... understood. In this case, Denmark is very highly developed, but a satellite in the global R&D and S&T system. With time and the growth of China as a R&D and S&T power house, both Denmark and China will benefit from brain circulation between them. Such brain circulation is likely to play a key role in flows...

  13. Quantum optical circulator controlled by a single chirally coupled atom

    Science.gov (United States)

    Scheucher, Michael; Hilico, Adèle; Will, Elisa; Volz, Jürgen; Rauschenbeutel, Arno

    2016-12-01

    Integrated nonreciprocal optical components, which have an inherent asymmetry between their forward and backward propagation direction, are key for routing signals in photonic circuits. Here, we demonstrate a fiber-integrated quantum optical circulator operated by a single atom. Its nonreciprocal behavior arises from the chiral interaction between the atom and the transversally confined light. We demonstrate that the internal quantum state of the atom controls the operation direction of the circulator and that it features a strongly nonlinear response at the single-photon level. This enables, for example, photon number–dependent routing and novel quantum simulation protocols. Furthermore, such a circulator can in principle be prepared in a coherent superposition of its operational states and may become a key element for quantum information processing in scalable integrated optical circuits.

  14. 高尚堡天然气处理装置改进与运行优化%Improvement and operation optimization of Gaoshangpu natural gas processing device

    Institute of Scientific and Technical Information of China (English)

    黄思宇; 吴印强; 朱聪; 孙立鹏

    2014-01-01

    The DHX condensation and separation process by propane and expansion refrigera-tion are used to recovery C +3 in Gaoshangpu natural gas processing device .Due to the decreasing of feed gas flow rate ,the increasing of CO2 and H2 S content in feed gas ,and the variations of processing device operating parameters ,a series of problems occurred including copper corrosion test unqualified in LPG ,equipment freezing and low propane recovery rate .Based on the analysis of existing problems ,processing technology was improved and the CO 2 and H2 S of feed gas were removed to reasonable range to solve the problem of equipment corrosion ,freezing and reduce the limit of acid component to the condensing temperature .The main adjustable parameters which can influence propane recovery rate and energy consumption of the device were screened out ,in-cluding the expander outlet pressure ,deethanizer operating pressure ,deethanizer bottom temper-ature ,and debutanizer operating pressure .By using HYSYS simulation to analyze the influence of the main adjustable parameters on propane recovery rate and energy consumption and to opti-mize the operating parameters ,the balance between propane recovery and energy consumption was realized and maximum benefit was achieved .After optimization ,although the energy cost in-crease 1 .081 million yuan every year ,but the product income increase 4 .398 million yuan ,the annual economic benefit increase 3 .317 million yuan .%高尚堡天然气处理装置采用丙烷+膨胀机制冷的D HX冷凝分离工艺回收C+3轻烃,由于原料气流量降低、气质组成中CO2和H2 S含量升高、处理装置操作参数变化造成液化气铜片腐蚀不合格、设备冻堵、丙烷收率低等问题。对装置存在问题进行分析后,改进处理工艺,脱除原料气中的CO2和H2 S至合理范围,解决液化气铜片腐蚀不合格和设备冻堵问题,降低酸性组分对装置冷凝温度的限制。筛选出影响装置

  15. Degradation of circulating thyroglobulin

    Energy Technology Data Exchange (ETDEWEB)

    Taura, M.; Yamashita, S.; Kubo, I.; Izumi, M.; Nagataki, S.

    1985-10-01

    In order to elucidate whether the derivatives of rat Tg in the peripheral circulation affect the results of kinetic studies of Tg, the present study was performed to investigate kinetics of rat Tg after separation of 19S Tg from its derivatives using gel-filtration. Radiolabeled Tg was obtained from thyroids of rats injected with SVI 24 hours before death, and subsequently purified by ammonium sulfate precipitation. The plasma samples obtained at varying time intervals after intravenous injection of SVI-rat Tg were fractionated on a Sephacryl S-300 column. As determined by sucrose density gradient, 99% of in vivo radiolabeled Tg was 19S. On gel-filtration, the injected labeled Tg and plasma samples obtained within two hours after injection showed a single peak in an identical area. A second peak in an area corresponding to a molecular weight of 60,000 to 70,000 appeared within six hours, and became as high as the first within 24 hours. In the second peak, 22.8% radioactivity was precipitated by anti-rat Tg antibody, and 14.4% of radioactivity of its TCA precipitate was not extracted by n-butanol. Thus, the second peak could affect the results of Tg kinetic studies which utilize TCA precipitation, n-butanol extraction or RIA procedures. The half life of rat Tg in the present study was calculated from the disappearance curves of radioactivity of 19S Tg separated from other radioactive substances.

  16. Contract System for Circulation of the Right to Rural Land Contractual Management

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    From the perspective of civil subject theory,law of value,comparative law and history of laws,the thesis expounds that the contract on the transfer of the contractual right of rural lands is in nature a civil contract instead of an administrative one.Then it explores the defects in the contract from the viewpoint of legal value goal,contract law and legal sociology,that is,the relevant provisions in Rural Land Contract Law and Explanations of Supreme People’s Court about the Issues concerning the Laws Applicable to the Trial of Cases of Disputes over Rural Land Contracting go against the principle of free contracting and run counter to the legal value goal of justice,so they do not achieve good implementing effect.Finally,the thesis demonstrates and makes some practical legislative proposals to perfect the contract system for circulation of the right to operate constructed rural lands,aiming at improving the circulation rate through perfecting the contract of the right to rural land contractual management,solving the disputes in rural lands circulation and safeguarding the legitimate rights of the farmers.

  17. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Keith, Raymond E.; Heller, Thomas J.; Bush, Stuart A.

    1991-01-01

    This Annual Report on Colorado-Ute Electric Association's NUCLA Circulating Fluidized Bed (CFB) Demonstration Program covers the period from February 1987 through December 1988. The outline for presentation in this report includes a summary of unit operations along with individual sections covering progress in study plan areas that commenced during this reporting period. These include cold-mode shakedown and calibration, plant commercial performance statistics, unit start-up (cold), coal and limestone preparation and handling, ash handling system performance and operating experience, tubular air heater, baghouse operation and performance, materials monitoring, and reliability monitoring. During this reporting period, the coal-mode shakedown and calibration plan was completed. (VC)

  18. [Assisted circulation with the heart-lung machine after cardiosurgical interventions: one year's experience with intra-aortal counter-pulsation with the heart-lung machine after cardiosurgical operations is reported (author's transl)].

    Science.gov (United States)

    Reichart, B; Kemkes, B; Kreuzer, E; Klinner, W; Holtz, J

    1978-02-17

    In the period from September 1976 to 1977, aortic or mitral valve replacement was performed in 84 and 34 patients respectively. Cardiogenic shock occurred during or immediately after the operation in 3 and 2 patients respectively (= 8.8% and 2.4%). In spite of the use of intra-aortal counter-pulsation, none of the patients survived the acute event. During the same period, 8 (= 5%) out of 113 patients who had undergone coronary surgery needed intra-aortal counter-pulsation. 4 of them survived the acute left heart failure and at the present time are clinically healthy (N.Y. Heart Association Class II).

  19. Refractory experience in circulating fluidized bed combustors, Task 7

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, R.Q.

    1989-11-01

    This report describes the results of an investigation into the status of the design and selection of refractory materials for coal-fueled circulating fluidized-bed combustors. The survey concentrated on operating units in the United States manufactured by six different boiler vendors: Babcock and Wilcox, Combustion Engineering, Foster Wheeler, Keeler Dorr-Oliver, Pyropower, and Riley Stoker. Information was obtained from the boiler vendors, refractory suppliers and installers, and the owners/operators of over forty units. This work is in support of DOE's Clean Coal Technology program, which includes circulating fluidized-bed technology as one of the selected concepts being evaluated.

  20. When Prostate Cancer Circulates in the Bloodstream

    Directory of Open Access Journals (Sweden)

    Virginie Vlaeminck-Guillem

    2015-10-01

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

  1. Transients in a circulating fluidized bed boiler

    Science.gov (United States)

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

    2013-11-01

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

  2. SOLID HOLDUP AND CIRCULATION RATE IN A LIQUID-SOLID CIRCULATING FLUIDIZED BED WITH VISCOUS LIQUID MEDIUM

    Directory of Open Access Journals (Sweden)

    N. Gnanasundaram

    2015-12-01

    Full Text Available Abstract Experiments were conducted in a liquid-solid circulating fluidized bed with different viscous liquids and particles to study the hydrodynamics, average solid hold up and solid circulation rate. The effects of operating parameters, i.e., primary liquid flow rate in the riser, auxiliary liquid flow rate, total liquid flow rate and viscosity of the liquid were studied for solids of different density and particle size. Results show that the circulating fluidization regime starts earlier for more viscous solutions because of the decrease in critical transitional velocity. The onset of solid holdup increases with an increase in liquid viscosity for sand and for glass beads. The solid circulation rate increases with an increase in total velocity and auxiliary velocity, and also increases with increasing viscosity.

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

    Science.gov (United States)

    2009-06-30

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

  4. The circulation physiology of agroecosystems

    Institute of Scientific and Technical Information of China (English)

    Cao Zhiping; Richard Dawson

    2007-01-01

    This paper represents an effort to enlarge the understanding of the biophysical foundation of agroecosystems by using an analogy with the circulation of the blood in the human body. The circulation function in the human body can be represented as arterial pressure. The factors affecting arterial pressure in the human body have direct counterparts in the cultivation-husbandry system. The relationship between circulation pressure and the factors affecting that pressure in the cultivation-husbandry system are similar to the relationship between the arterial pressure and factors affecting arterial pressure in the human body. Furthermore, circulation resistance in the cultivation-husbandry system can be shown to be analogous to the calculation of peripheral resistance in the human body by Poiseuille's formula.

  5. A review of existing gas-cooled reactor circulators with application of the lessons learned to the new production reactor circulators

    Energy Technology Data Exchange (ETDEWEB)

    White, L.S.

    1990-07-01

    This report presents the results of a study of the lessons learned during the design, testing, and operation of gas-cooled reactor coolant circulators. The intent of this study is to identify failure modes and problem areas of the existing circulators so this information can be incorporated into the design of the circulators for the New Production Reactor (NPR)-Modular High-Temperature Gas Cooled Reactor (MHTGR). The information for this study was obtained primarily from open literature and includes data on high-pressure, high-temperature helium test loop circulators as well as the existing gas cooled reactors worldwide. This investigation indicates that trouble free circulator performance can only be expected when the design program includes a comprehensive prototypical test program, with the results of this test program factored into the final circulator design. 43 refs., 7 tabs.

  6. Optimization of coolant arrangement for fusion-fission hybrid reactor and analysis of ex-core nature circulation%聚变-裂变混合堆冷却剂布置优化及堆外自然循环分析

    Institute of Scientific and Technical Information of China (English)

    喻章程; 解衡

    2013-01-01

    The simulation and numerical computation with FLUENT code are conducted for the fuel zone of fusion-fission hybrid reactor.Two coolant flowing arrangement schemes,uniform flow,and proportional flow based on the gross heat of each fuel cell,are compared for optimization.The results of the numerical computation show that the heat conduction between adjacent fuel cells is weak and the heat is carried away by the coolant in the duct,and it is almost completely equal to the heat produced by corresponding fuel cell except the fuel cell 1.Then the value of heat structure of the coolant duct is the gross heat of each fuel cell that means there is no need to remodel the fuel zone with system analysis program.The fuel zone has lower maximum temperature and more even temperature distribution in the case of proportional flow compared with uniform flow,but the effect of flattening temperature is not obvious.The capacity of heat transfer of ex-core nature circulation in the imaginary LOCA is also evaluated.The results show that the reactor core will be melted within 520s after shut-down without the nature circulation and the maximum temperature in the fuel region will be only elevated to 584.4℃ within 1000s after shut-down if with the nature circulation.%根据聚变-裂变混合堆概念堆型的燃料区水冷设计,通过FLUENT建模和模拟计算,比较了均匀流量和按燃料单元发热量比例分配流量两种冷却剂布置方案.数值计算结果表明,这两种布置方案中燃料单元之间的导热很小,除燃料单元1中冷却管道外,其余的冷却管道带走的热量几乎等于相应燃料单元的发热量,在用系统分析程序等效建模时,不必重新确定冷却管道的热构件;对后一种布置方案燃料区的最高温度更低,温度分布更均匀,但温度展平效果并不明显.计算了堆外自然循环系统在假设的失水事故(LOCA)中的导热能力.结果表明,如果不采用自然循环系统,停堆后520s

  7. The Motivation Analysis of Rural Land Circulation and Legal Countermeasures Research

    OpenAIRE

    Yongyong Zhu

    2014-01-01

    It’s the aim of this rural land circulation article to develop China Modern Agriculture, to achieve scale operation, to solve the Three Rural issues. Rural land circulation is the trend of China's agriculture development. It is the key of Three Rural issues. In the background of maintaining coordinated developments in rural and urban regions and the background of the constructions of new socialist rural area, we should encourage the various the rural land circulation forms, encourage the farm...

  8. Microsurgical management of posterior circulation aneurysms

    Directory of Open Access Journals (Sweden)

    SHI Xiang-en

    2012-02-01

    Full Text Available Objective To retrospectively analyze effective methods for surgical management of posterior circulation aneurysms. Methods There were 42 patients with posterior circulation aneurysms [26 cases of basilar aneurysm (27 aneurysms, 16 cases of vertebral aneurysm (17 aneurysms]. There were 15 patients underwent bypass surgery [4 external carotid artery-P2 segment of posterior cerebral artery (ECA-P2, 2 internal carotid artery-P2 segment of posterior cerebral artery (ICA-P2, 2 internal maxillary artery-P2 segment of posterior cerebral artery (IMA-P2, 2 intracranial segment of vertebral artery-extracranial segment of vertebral artery, 5 occipital artery-posterior inferior cerebellar artery (OA-PICA] and 27 patients underwent simple surgical clipping. Results Activities of daily life of 37 patients recovered to normal (14 patients with aneurysm on the top of basilar artery, 3 with aneurysm on the trunk of basilar artery, 9 with vertebral aneurysm, 5 with posterior inferior cerebellar artery aneurysm, 4 with aneurysm on the junction of P1-P2 segment of posterior cerebral artery, 1 with superior cerebellar artery, and 1 with anterior inferior cerebellar aneurysm. None of them occurred operation-related neurological dysfunction. The recovery rate was 88.09% . Among the other patients, 1 with aneurysm on the top of basilar artery presented severe signs and symptoms of neurological defect and cannot take care of oneself, 2 patients (1 with aneurysm on the top of basilar artery, 1 with aneurysm on the trunk of basilar artery occurred brain stem hemorrhage after operation, and died at perioperative period, 2 with vertebral aneurysm relapsed and was cured after treatment. Conclusion Posterior circulation aneurysm which is not suitable for surgical clipping can be treated with intra? and extra?cranial vessel bypass. It may avoid the risk of surgical clipping of aneurysm.

  9. Semicarbazide-sensitive amine oxidase (SSAO): from cell to circulation

    NARCIS (Netherlands)

    F. Boomsma (Frans); H. Hut; U. Bagghoe; A.H. van den Meiracker (Anton)

    2005-01-01

    textabstractSemicarbazide-sensitive amine oxidase (SSAO) is a multi-functional enzyme widely present in nature. It converts primary amines into their corresponding aldehydes, while generating H(2)O(2) and NH(3). In mammals, SSAO circulates in plasma, while a membrane-bound form (of

  10. Semicarbazide-sensitive amine oxidase (SSAO): from cell to circulation

    NARCIS (Netherlands)

    F. Boomsma (Frans); H. Hut; U. Bagghoe; A.H. van den Meiracker (Anton)

    2005-01-01

    textabstractSemicarbazide-sensitive amine oxidase (SSAO) is a multi-functional enzyme widely present in nature. It converts primary amines into their corresponding aldehydes, while generating H(2)O(2) and NH(3). In mammals, SSAO circulates in plasma, while a membrane-bound form

  11. Pressurized circulating fluidized bed combustion technology

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez-Malebran, S.; Anglesea, W.T. [Fluent Europe Limited, Sheffield (United Kingdom)

    1998-12-31

    This report describes how the FLUENT computations fluid dynamics code has been provided with a granular (gas-solids), multiphase flow-modelling capability in order to simulate the operation of a circulating fluidized bed combustion chamber. The new multiphase module solves the conservation equations for each phase on an Eulerian basis and it currently enables gas phase reactions and interphase heat and momentum transfer to be modelled. Because of fundng restrictions, the module has not yet been provided with a general capability for modelling interphase mass transfer and therefore approximations have to be made when simulating coal combustion. Having developed the code and carried out basic testing, it has been used to simulate one set of conditions in the circulating fluidized bed combustion test facility operated by RWE Energie AG at Niederaussem Germany. Considering the simplifications made in this simulation, the level of agreement between the code results and the available measurements and observations is very encouraging. 18 refs., 5 figs., 2 tabs.

  12. Satellite Altimetry, Ocean Circulation, and Data Assimilation

    Science.gov (United States)

    Fu, Lee-Lueng

    1999-01-01

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

  13. Temperature stratification in a hot water tank with circulation pipe

    DEFF Research Database (Denmark)

    Andersen, Elsa

    1998-01-01

    The aim of the project is to investigate the change in temperature stratification due to the operation of a circulation pipe. Further, putting forward rules for design of pipe inlet in order not to disturb the temperature stratification in the hot water tank. A validated computer model based...

  14. Market Research and Magazine Circulation Promotion: A Case Study.

    Science.gov (United States)

    Van Tubergen, G. Norman

    When a major national news magazine decided to advertise on television to increase circulation, market researchers had to design research procedures that would assess the effectiveness of various advertising options. The system was designed around the toll-free telephone number given in the advertisement, with the receiving operator recording the…

  15. DEVELOPMENT POTENTIALS AND RESEARCH NEEDS IN CIRCULATING FLUIDIZED BED COMBUSTION

    Institute of Scientific and Technical Information of China (English)

    Lothar Reh

    2003-01-01

    First a report about present status of circulating fluidized bed reactors for coal and multi-fuel combustion in power plants is given. Thereafter the development potentials and research needs for further improvement of CFB combustors operating with finely grained bed materials are discussed and recommendations for direction of further research and development work are presented.

  16. Naturalizing neoliberalism and the de-Mexicanization of the tequila industry

    OpenAIRE

    Marie Sarita Gaytán; Sarah Bowen

    2015-01-01

    Although scholars agree that nationalism remains an important aspect of the new vocabulary of neoliberalism, little is known about how these discourses operate on the ground and in particular contexts. In this paper, we investigate how a specific adaption of national identity, one that underscores the values of cultural integrity, is used to naturalize neoliberal shifts in the tequila industry. Tequila has long circulated in the images and myths of Mexican identity. However, in the last two d...

  17. Coastal circulation in the North Indian Ocean: Coastal segment (14,S-W)

    Digital Repository Service at National Institute of Oceanography (India)

    Shetye, S.R.; Gouveia, A.D.

    and as a result the circulation shows a distinct seasonal character. The nature of winds, precipitation, runoff, and tides in the region are summarized. Characteristics of large-scale near surface circulation and of water masses in the North Indian Basin...

  18. Seasonal overturning circulation in the Red Sea: 2. Winter circulation

    KAUST Repository

    Yao, Fengchao

    2014-04-01

    The shallow winter overturning circulation in the Red Sea is studied using a 50 year high-resolution MITgcm (MIT general circulation model) simulation with realistic atmospheric forcing. The overturning circulation for a typical year, represented by 1980, and the climatological mean are analyzed using model output to delineate the three-dimensional structure and to investigate the underlying dynamical mechanisms. The horizontal model circulation in the winter of 1980 is dominated by energetic eddies. The climatological model mean results suggest that the surface inflow intensifies in a western boundary current in the southern Red Sea that switches to an eastern boundary current north of 24N. The overturning is accomplished through a cyclonic recirculation and a cross-basin overturning circulation in the northern Red Sea, with major sinking occurring along a narrow band of width about 20 km along the eastern boundary and weaker upwelling along the western boundary. The northward pressure gradient force, strong vertical mixing, and horizontal mixing near the boundary are the essential dynamical components in the model\\'s winter overturning circulation. The simulated water exchange is not hydraulically controlled in the Strait of Bab el Mandeb; instead, the exchange is limited by bottom and lateral boundary friction and, to a lesser extent, by interfacial friction due to the vertical viscosity at the interface between the inflow and the outflow. Key Points Sinking occurs in a narrow boundary layer along the eastern boundary Surface western boundary current switches into an eastern boundary current Water exchange in the Strait of Bab el Mandeb is not hydraulically controlled © 2014. American Geophysical Union. All Rights Reserved.

  19. The Invertibility, Explicit Determinants, and Inverses of Circulant and Left Circulant and g-Circulant Matrices Involving Any Continuous Fibonacci and Lucas Numbers

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available Circulant matrices play an important role in solving delay differential equations. In this paper, circulant type matrices including the circulant and left circulant and g-circulant matrices with any continuous Fibonacci and Lucas numbers are considered. Firstly, the invertibility of the circulant matrix is discussed and the explicit determinant and the inverse matrices by constructing the transformation matrices are presented. Furthermore, the invertibility of the left circulant and g-circulant matrices is also studied. We obtain the explicit determinants and the inverse matrices of the left circulant and g-circulant matrices by utilizing the relationship between left circulant, g-circulant matrices and circulant matrix, respectively.

  20. Self-biased circulators for high power applications

    Science.gov (United States)

    Sokolov, Alexander S.

    Self-biased circulators exploit the properties of high anisotropy magnetic field in hexagonal ferrites, thus allowing operation without biasing magnets and a significant size and weight reduction. Although first self-biased circulators were demonstrated more than 20 years ago, all the prototypes constructed so far are unsuitable for practical applications. An attempt to design a self-biased circulator from scratch was made. Novel exceptionally low dielectric loss and high heat conductivity ceramic materials were developed and innovative substrate synthesis techniques were employed. Low temperature cofiring of green body ferrite compacts and dielectric ceramic slurries were mastered, resulting in solid composite substrates. Original device design was developed. Key features (including wide coupling angles, wide microstriplines, thick substrate, and absence of impedance transformers) enable low insertion loss, broadband operation, high power handling, and compact size. Fabrication and testing of Ka band Y-junction self-biased circulator are reported herein. Furthermore, design approach and fabrication techniques developed here can be readily applied for the construction of X-band self-biased circulators, provided that suitable ferrite materials are available. Low temperature cofiring of ferrite and dielectric materials is especially beneficial for various RF and high-frequency applications. Multiple devices can be readily fabricated on a single wafer using conventional lithographic techniques, resulting in true microwave monolithic integrated circuit.

  1. SUBSTATIONS OF DISTRICT HEATING SYSTEMS WITH PULSE COOLANT CIRCULATION

    Directory of Open Access Journals (Sweden)

    Andrey N. Makeev

    2017-01-01

    Full Text Available Abstract. Objectives The aim of the study is to generalise the results of the application of technologies and means for organising pulse coolant flow within a district heating system in order to increase its energy efficiency based on the organisation of local hydraulic shocks and the subsequent use of their energy to ensure the purification of heat energy equipment, intensify the heat transfer process and realise the possibility of transforming the available head from one hydraulic circuit to another. Methods Substations connecting the thermal power installations of consumers with heat networks via dependent and independent schemes are analytically generalised. The use of pulse coolant circulation is proposed as a means of overcoming identified shortcomings. Results Principal schemes of substations with pulse coolant circulation for dependent and independent connection of thermal power installations are detailed. A detailed description of their operation is given. The advantages of using pulse coolant circulation in substations are shown. The materials reflecting the results of the technical implementation and practical introduction of this technology are presented. Conclusion Theoretical analysis of the operation of the basic schemes of substations with pulse coolant circulation and the results of their practical application, as well as the materials of scientific works devoted to the use of the energy of a hydraulic impact and the study of the effect of pulse coolant flow on thermal and hydrodynamic processes, have yielded a combination of factors reflecting technical and economic rationality of application of pulse coolant circulation

  2. Circulating Fibronectin Controls Tumor Growth

    Directory of Open Access Journals (Sweden)

    Anja von Au

    2013-08-01

    Full Text Available Fibronectin is ubiquitously expressed in the extracellular matrix, and experimental evidence has shown that it modulates blood vessel formation. The relative contribution of local and circulating fibronectin to blood vessel formation in vivo remains unknown despite evidence for unexpected roles of circulating fibronectin in various diseases. Using transgenic mouse models, we established that circulating fibronectin facilitates the growth of bone metastases by enhancing blood vessel formation and maturation. This effect is more relevant than that of fibronectin produced by endothelial cells and pericytes, which only exert a small additive effect on vessel maturation. Circulating fibronectin enhances its local production in tumors through a positive feedback loop and increases the amount of vascular endothelial growth factor (VEGF retained in the matrix. Both fibronectin and VEGF then cooperate to stimulate blood vessel formation. Fibronectin content in the tumor correlates with the number of blood vessels and tumor growth in the mouse models. Consistent with these results, examination of three separate arrays from patients with breast and prostate cancers revealed that a high staining intensity for fibronectin in tumors is associated with increased mortality. These results establish that circulating fibronectin modulates blood vessel formation and tumor growth by modifying the amount of and the response to VEGF. Furthermore, determination of the fibronectin content can serve as a prognostic biomarker for breast and prostate cancers and possibly other cancers.

  3. Adjustable hybrid gas bearing – Influence of piezoelectrically adjusted injection on damping factors and natural frequencies of a flexible rotor operating under critical speeds

    DEFF Research Database (Denmark)

    Pierart, Fabián G.; Santos, Ilmar F.

    2016-01-01

    fourradial injectors equally pressurized. For the two configurations, the theoretical results are experimentally validated as afunction of the piezoactuators input voltage and the journal angular velocity. Results show a good agreement for natural frequencies and damping factors. Theoretical and experimental...

  4. Atmospheric Circulation of Terrestrial Exoplanets

    CERN Document Server

    Showman, Adam P; Merlis, Timothy M; Kaspi, Yohai

    2013-01-01

    The investigation of planets around other stars began with the study of gas giants, but is now extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated by this observational tide, we survey the basic dynamical principles governing the atmospheric circulation of terrestrial exoplanets, and discuss the interaction of their circulation with the hydrological cycle and global-scale climate feedbacks. Terrestrial exoplanets occupy a wide range of physical and dynamical conditions, only a small fraction of which have yet been explored in detail. Our approach is to lay out the fundamental dynamical principles governing the atmospheric circulation on terrestrial planets--broadly defined--and show how they can provide a foundation for understanding the atmospheric behavior of these worlds. We first survey basic atmospheric dynamics, including the role of geostrophy, baroclinic instabilities, and jets in the strongly rotating regime (the "extratropics") and the role of the Hadle...

  5. 自然循环蒸汽发生器倒U型管内倒流现象影响因素研究%Investigation on Factors Affecting Reverse Flow in Inverted U-Tubes of Steam Generator Under Natural Circulation

    Institute of Scientific and Technical Information of China (English)

    郝建立; 陈文振; 王少明

    2013-01-01

    For natural circulation, it is shown that reverse flow occurs in the inverted U-tubes of steam generator (SG) at certain low power levels. A flow model based on one-dimensional Oberbeck-Boussinesq equation was formulated to analyze this phenomenon. Two SGs of different scales were calculated. The results show that the reverse flow phenomenon occurs easily in the shorter U-tubes in small SG, but the phenomenon occurs easily in the longer U-tubes in large SG. The inlet temperature has great influence on the occurrence of reverse flow.%在某些自然循环工况下,蒸汽发生器部分倒U型管内存在倒流现象.基于一维OberbeckBoussinesq方程,建立了蒸汽发生器并联倒U型管内单相水流动传热模型,并以两种尺寸的蒸汽发生器为例进行了计算.计算结果表明,小型蒸汽发生器内短管易发生倒流,大型蒸汽发生器内长管易发生倒流;蒸汽发生器进口水温对倒流现象的发生具有重要的影响.

  6. 33 CFR 127.305 - Operations Manual.

    Science.gov (United States)

    2010-07-01

    ...) WATERFRONT FACILITIES WATERFRONT FACILITIES HANDLING LIQUEFIED NATURAL GAS AND LIQUEFIED HAZARDOUS GAS Waterfront Facilities Handling Liquefied Natural Gas Operations § 127.305 Operations Manual. Each...

  7. Natural gas; Gas Natural

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carlos A.; Moraes, Claudia C.D. [Eletricidade de Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil); Fonseca, Carlos H.F. [Centrais Eletricas de Santa Catarina S.A., Florianopolis, SC (Brazil); Silva, Clecio Fabricio da; Alves, Ricardo P. [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil); Sposito, Edivaldo Soares; Hulle, Lutero [Espirito Santo Centrais Eletricas S.A. (ESCELSA), Vitoria, ES (Brazil); S. Martins, Icaro da [Centrais Eletricas do Norte do Brasil S.A. (ELETRONORTE), Belem, PA (Brazil); Vilhena, Joao Luiz S. de [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Fagundes, Zaluar Aquino [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    1996-12-31

    An increase in the consumption of natural gas in Brazil is an expected fact in what concerns energetic planning. This work presents the existing situation in what concerns natural gas utilization in the main world economies, as well as an analysis of the participation of this fuel among the energy final consumption per sources. The Brazilian consumption of natural gas is also analysed as well as the international agreement between Brazil and Bolivia for natural gas commercialization. Some legal, institutional and political aspects related to natural gas commercialization are also discussed. Finally, several benefits to be brought by the utilization of natural gas are presented 10 refs., 3 tabs.

  8. Research on the utilization of circulating fluidized bed combustion ashes

    Energy Technology Data Exchange (ETDEWEB)

    Jahn, P.; Weis, P. (EAB Energie-Anlagen Berlin GmbH, Berlin (Germany, F.R.))

    1989-09-01

    Power plant residues from the Moabit, Berlin, Power Plant, which is currently under construction (circulating fluidized bed), must be utilized in accordance with the notice of consent. In order to meet this condition, extensive investigations are being carried out during the design and planning stage. In addition to preliminary tests in a fluidized bed pilot plant, representative circulating fluidized bed ash testing experience has been accumulated in a major test in an operating plant. The paper presents the results of the first physical construction material investigations together with possible solutions for applications at the Berlin West site. 2 refs., 11 figs., 1 tab.

  9. From geosphere to biosphere: circulation of matter in nature

    Directory of Open Access Journals (Sweden)

    Rodrigues, Ana Paula L.

    2011-11-01

    Full Text Available Con este experimento, para alumnos de la educación secundaria, se pretende estimular el gusto por la ciencia experimental. De una manera lúdica, vamos a intentar ejemplificar el movimiento de la materia en la naturaleza e ilustrar las consecuencias que los desequilibrios en los ciclos biogeoquímicos pueden tener para los seres vivos.

  10. Investigations on Cationic Exchange Capacity and Unused Bed Zone according to operational conditions in a Fixed Bed Reactor for water lead removal by a natural zeolite

    Directory of Open Access Journals (Sweden)

    Barthélemy JP.

    2006-01-01

    Full Text Available In this study, attention has been focused on the behaviour of the Cationic Exchange Capacity (CEC and the Unused Bed Zone (UBZ, according to the operating parameters (bed length: L, column diameter: D, particle diameter: d and fl ow rate: Q in a Fixed Bed Reactor (FBR. The investigations are performed for a single-component study of lead on New Zealand clinoptilolite at 25 ± 1°C. The results show a constant operating CEC of 1.00 ± 0.015 meq.g-1 which is independent of the operational parameters listed above. The performance of the operations expressed as UBZ, shows an optimum for the ratio L/D (bed length and column diameter fi xed at 18.1, for Q = 2.9 BV.h-1 (bed volume per hour and particle diameter d = 0.38 mm (the ratio particle diameter on column diameter d/D at 0.057. This maximum performance is reached with the lowest UBZ value of 5.6% of the operating CEC. Overall interpretation drawn from the results according to UBZ shows that decreasing the particles size improves the performance of ion exchange process; as well as decreasing the fl ow rate. Nevertheless, the increase of L/D to a certain extent does not improve ion exchange performances.

  11. On Willingness of Rural Land Circulation and Securitization in Central Regions of China

    Institute of Scientific and Technical Information of China (English)

    Jianxin; LU; Yuwei; SU

    2014-01-01

    On the basis of questionnaire survey in 54 natural villages of 22 cities( counties) in 6 central region provinces,this paper analyzed the willingness of rural land circulation and securitization and influencing factors with the aid of Logistic model and Multinomial Logit model.The study indicates that factors influencing willingness of rural land circulation and securitization mainly include land contract method,land circulation information and approaches,rights and interests of farmers infringed or not,policies of benefiting farmers,and non-agricultural skills. Finally,it came up with following pertinent policy recommendations:( 1) reforming and improving land contract methods;( 2)strengthening disclosure of land circulation information;( 3) reforming and improving land circulation approaches;( 4) strengthening protection of farmers’ rights and interests in the process of land circulation;( 5) reinforcing and implementing policies benefiting farmers;( 6) cultivating and developing farmers’ non-agricultural skills.

  12. Changes in the strength and width of the Hadley circulation since 1871

    Directory of Open Access Journals (Sweden)

    J. Liu

    2012-03-01

    Full Text Available Recent studies demonstrate that the Hadley Circulation has intensified and expanded for the past three decades, which has important implications for subtropical societies and may lead to profound changes in global climate. However, the robustness of this intensification and expansion that should be considered when interpreting long-term changes of the Hadley Circulation is still matters of debate. It also remains largely unknown how the Hadley Circulation has evolved over longer periods. Here we present long-term variability of the Hadley Circulation using the 20th Century Reanalysis. It shows a slight strengthening and widening of the Hadley Circulation since the late 1970s, which is not inconsistent with recent assessments. However, over centennial timescales (1871–2008, the Hadley Circulation shows a tendency towards more intense and narrower state. More importantly, the width of the Hadley Circulation has not yet completed a life-cycle since 1871. The strength and width of the Hadley Circulation during the late 19th and early 20th century show strong natural variability, exceeding variability that coincides with global warming in recent decades. These findings raise the question that the recent change of the Hadley Circulation is primarily attributed to greenhouse warming or a long-period oscillation of the Hadley Circulation substantially longer than that observed in previous studies.

  13. ENDEMIC ORTHOPOXVIRUS CIRCULATING IN PROCYONIDS IN MEXICO.

    Science.gov (United States)

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

    2016-07-01

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

  14. Circulating Tumor Cells Measurements in Hepatocellular Carcinoma

    Directory of Open Access Journals (Sweden)

    Franck Chiappini

    2012-01-01

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

  15. Factors influencing the presence of circulating differentiated thyroid cancer cells in the thyroidectomy perioperative period*

    Institute of Scientific and Technical Information of China (English)

    Wentao Wei; Qinjiang Liu; Wei Yao

    2015-01-01

    Objective The aim of the study was to detect circulating differentiated thyroid cancer (DTC) micrometas-tasis and to investigate the factors influencing their presence in the perioperative thyroidectomy period. Methods DTC micrometastases in the peripheral blood were detected with flow cytometry, and patient clinical and pathological factors were analyzed in 327 DTC patients.Results Circulating blood micrometastases were present in the peripheral circulation at a higher rate 1 week postoperatively than preoperatively and at 4 weeks postoperatively (P 0.05). At 4 weeks postoperatively, the presence of circulating micrometastasis was not associated with tumor size or lymph node stage (P > 0.05), but was associated with poorly differentiated tumors (P < 0.05). Conclusion The presence of circulating DTC micrometastases correlates to tumor size, lymph node stage, and operative manipulation. The differentiation degree of the tumors were associated with the persistent presence of micrometastasis in the circulating blood.

  16. VanderLaan Circulant Type Matrices

    Directory of Open Access Journals (Sweden)

    Hongyan Pan

    2015-01-01

    Full Text Available Circulant matrices have become a satisfactory tools in control methods for modern complex systems. In the paper, VanderLaan circulant type matrices are presented, which include VanderLaan circulant, left circulant, and g-circulant matrices. The nonsingularity of these special matrices is discussed by the surprising properties of VanderLaan numbers. The exact determinants of VanderLaan circulant type matrices are given by structuring transformation matrices, determinants of well-known tridiagonal matrices, and tridiagonal-like matrices. The explicit inverse matrices of these special matrices are obtained by structuring transformation matrices, inverses of known tridiagonal matrices, and quasi-tridiagonal matrices. Three kinds of norms and lower bound for the spread of VanderLaan circulant and left circulant matrix are given separately. And we gain the spectral norm of VanderLaan g-circulant matrix.

  17. In vivo acoustic and photoacoustic focusing of circulating cells

    Science.gov (United States)

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

    2016-03-01

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

  18. The complexity, function and applications of RNA in circulation

    Directory of Open Access Journals (Sweden)

    Alton eEtheridge

    2013-06-01

    Full Text Available Blood carries a wide array of biomolecules, including nutrients, hormones and molecules that are secreted by cells for specific biological functions. The recent finding of stable RNA of both endogenous and exogenous origin in the circulation raises a number of questions and opens a broad, new field: exploring the origins, functions and applications of these extracellular RNA molecules. These findings raise many important questions, including: what are the mechanisms of export and cellular uptake, what is the nature and source of their stability, what molecules do they interact with in the blood, and what are the possible biological functions of the circulating RNA. This review summarizes some key recent developments in circulating RNA research and discusses some of the open questions in the field.

  19. Conservation of Circulation in Magnetohydrodynamics

    CERN Document Server

    Bekenstein, J D; Bekenstein, Jacob D.; Oron, Asaf

    2000-01-01

    We demonstrate, both at the Newtonian and (general) relativistic levels, theexistence of a generalization of Kelvin's circulation theorem (for pure fluids)which is applicable to perfect magnetohydrodynamics. The argument is based onthe least action principle for magnetohydrodynamic flow. Examples of the newconservation law are furnished. The new theorem should be helpful inidentifying new kinds of vortex phenomena distinct from magnetic ropes or fluidvortices.

  20. Circulation in gas-slurry column reactors

    Energy Technology Data Exchange (ETDEWEB)

    Clark, N.; Kuhlman, J.; Celik, I.; Gross, R.; Nebiolo, E.; Wang, Yi-Zun.

    1990-08-15

    Circulation in bubble columns, such as those used in fischer-tropsch synthesis, detracts from their performance in that gas is carried on average more rapidly through the column, and the residence time distribution of the gas in the column is widened. Both of these factors influence mass-transfer operations in bubble columns. Circulation prediction and measurement has been undertaken using probes, one-dimensional models, laser Doppler velocimetry, and numerical modeling. Local void fraction was measured using resistance probes and a newly developed approach to determining air/water threshold voltage for the probe. A tall column of eight inch diameter was constructed of Plexiglas and the distributor plate was manufactured to distribute air evenly through the base of the column. Data were gathered throughout the volume at three different gas throughputs. Bubble velocities proved difficult to measure using twin probes with cross-correlation because of radial bubble movement. A series of three-dimensional mean and RMS bubble and liquid velocity measurements were also obtained for a turbulent flow in a laboratory model of a bubble column. These measurements have been made using a three-component laser Doppler velocimeter (LDV), to determine velocity distributions non-intrusively. Finally, the gas-liquid flow inside a vertically situated circular isothermal column reactor was simulated numerically. 74 refs., 170 figs., 5 tabs.

  1. Eyes of the Storm: Can Fusion Centers Play a Crucial Role During the Response Phase of Natural Disasters Through Collaborative Relationships With Emergency Operations Centers?

    Science.gov (United States)

    2014-09-01

    sector infrastructure owner/operators. The consortium was able to identify gas stations, banks, restaurants , pharmacies, and hotels that were open for...a state of heavy reliance on interconnectivity through technology and modern conveniences . This reality can strain resources in a steady state

  2. Optimization and operation of RNG-unit for production of reformed natural gas integrated with standard CHP unit; Optimering og drift af RNG-enhed til produktion af reformeret naturgas integreret med standard kraftvarmeenhed

    Energy Technology Data Exchange (ETDEWEB)

    Soegaard, C.; Schramm, J.

    2004-02-01

    A steam reforming unit has been developed during this project. The unit converts natural gas into reformed natural gas (RNG), which contain hydrogen. The RNG is combusted in an SI engine, which produces power and heat. Hydrogen was supposed to reduce hydrocarbon emissions and increase the combustion efficiency. An efficient control strategy has been developed, and the plant has been operating automatically without problems for more than one week. An increase in power efficiency of 0,5% was achieved, but almost no reduction in hydrocarbon emissions. However, the engine was unable to operate at excess air ratios beyond 2, where 10% reduction in unburned hydrocarbon emissions was seen. It is believed that larger plants, which operates with more excess air, will demonstrate more reduction in unburned hydrocarbons with RNG. An increase in compression ratio with RNG over NG is possible since the engine operates more stable on RNG. This could further improve power efficiency with 2-3%. The payback time for the plant was calculated to be 81 years without the effect from increased compression ratio. This does not support implementation of the plant in practice. (au)

  3. Optimal Backward Perturbation Analysis for the Block Skew Circulant Linear Systems with Skew Circulant Blocks

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available We first give the block style spectral decomposition of arbitrary block skew circulant matrix with skew circulant blocks. Secondly, we obtain the singular value of block skew circulant matrix with skew circulant blocks as well. Finally, based on the block style spectral decomposition, we deal with the optimal backward perturbation analysis for the block skew circulant linear system with skew circulant blocks.

  4. Interactions Between the Thermohaline Circulation and Tropical Atlantic SST in a Coupled General Circulation Model

    Science.gov (United States)

    Miller, Ron; Jiang, Xing-Jian; Travis, Larry (Technical Monitor)

    2001-01-01

    Tropical Atlantic SST shows a (statistically well-defined) decadal time scale in a 104-year simulation of unforced variability by a coupled general circulation model (CGCM). The SST anomalies superficially resemble observed Tropical Atlantic variability (TAV), and are associated with changes in the atmospheric circulation. Brazilian rainfall is modulated with a decadal time scale, along with the strength of the Atlantic trade winds, which are associated with variations in evaporation and the net surface heat flux. However, in contrast to observed tropical Atlantic variability, the trade winds damp the associated anomalies in ocean temperature, indicating a negative feedback. Tropical SST anomalies in the CGCM, though opposed by the surface heat flux, are advected in from the Southern Hemisphere mid-latitudes. These variations modulate the strength of the thermohaline circulation (THC): warm, salty anomalies at the equator sink drawing cold, fresh mid-latitude water. Upon reaching the equator, the latter inhibit vertical overturning and advection from higher latitudes, which allows warm, salty anomalies to reform, returning the cycle to its original state. Thus, the cycle results from advection of density anomalies and the effect of these anomalies upon the rate of vertical overturning and surface advection. This decadal modulation of Tropical Atlantic SST and the thermohaline circulation is correlated with ocean heat transport to the Northern Hemisphere high latitudes and Norwegian Sea SST. Because of the central role of equatorial convection, we question whether this mechanism is present in the current climate, although we speculate that it may have operated in palaeo times, depending upon the stability of the tropical water column.

  5. EVALUATION OF THE THIXOTROPY OF OIL-WELL CEMENTS USED FOR CEMENTING LOST CIRCULATION ZONES: EFFECT OF PLASTER AND BLAST FURNACE SLAG

    Directory of Open Access Journals (Sweden)

    T. Bouziani

    2015-08-01

    Full Text Available Cementing of oil and gas wells can be a very delicate operation. Among the concerns of service companies, during this operation are the nature and conditions of the formations in well. This is the case of cementing operations in southern Algeria, specifically on the fields of In-Amen, where the formations in lost zones are naturally weak and highly permeable. In these areas, drilling fluids (muds and cements pumped will be, completely or partially lost, what we call "lost circulation". Thixotropic cements are useful to overcome lost circulation problems. They are characterized by a special rheological behavior, allowing it to plug lost zones when they are pumped.Our work aims to assess the thixotropy of cements perapred with two types of cement (class G Asland cement and CEM I 42.5 portland cement with the plaster, using a viscometer with coaxial cylinder (couette type. Moreover, the effect of blast furnace slag (LHF on the properties and thixotropic mixtures prepared was also studied. The results show that portland cement (available locally can produce mixes with higher and more stable thixotropy than the class G cement (from importation, which is a practical and economical for cementing job operations in wells with loss zones. The results also show that the effect of LHF is positive, since in addition to his contribution to long term performances, especially the durability of hardened concrete, it improves the thixotropy of cement made of plaster.

  6. Market Governance Structure and Industrial Operation Pattern --Theoretical Study on Competitive and Monopolistic Situation of China's Circulation Industry%市场治理结构与产业运行格局——对中国流通产业竞争和垄断现状的理论考察

    Institute of Scientific and Technical Information of China (English)

    何大安

    2012-01-01

    Market governance structure is in many aspects of system design and implementation as the core content and the basic framework. There is a correlation between the market governance structure and industrial operation pattern. Market governance structure can be analysised from established system and non-established system at two levels. Market governance structure established means that the economic and institutional model and contractual way of linking are less change or not change. Market governance structure non-established is the result of the economic and institutional mode and the compact way of linking frequent changes. Market governance structure and industrial run pattern of China's circulation industry are as grade transaction and mixed transaction the main content. This paper analyzes the partial monopoly of China's circulation industry, and believes that the market organization of China's circulation industry is the coexistence of perfect competition and partial monopoly.%经济学家对市场治理结构的理论和实践问题的探讨,在许多方面是以制度的设计和实施为核心内容和基本架构的。市场治理结构与产业运行格局之间存在着相关性。市场治理结构作为一种制度安排.可以分别从制度既定和制度不既定两个层面来进行分析。市场治理结构既定。意味着经济体制模式和契约联结方式较少发生变动或不发生变动:市场治理结构不既定,是经济体制模式和契约联结方式经常发生变动的结果。西方产业组织理论只是部分适合于对中国流通产业运行实际的解释。分析中国流通产业的市场治理结构和产业运行格局.要以体制转轨和不完全契约作为宏微观分析背景.重点分析以等级交易和混合交易为主要内容的契约联结方式.并据此来研究流通产业的竞争和垄断。本文以现实的市场治理结构为背景.考察了中国流通产

  7. Structure and operation of the natural gas market in France; La structure et le fonctionnement du marche du gaz naturel en France

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    The French natural gas market is organized around six main activities: production, transport, methane terminals, storage, distribution and commercialization. This paper describes the facilities related to each activity: gas fields, pipelines network and distribution systems, terminals capacity and underground storage facilities. The selling activity is opened to competition but the French gas market follows a progressive and controlled opening which will be complete in July 2007. (J.S.)

  8. Optimised operation and management of natural gas distribution systems with the geographic information system GIS; Gasnetze besser verwalten und optimieren mit GIS

    Energy Technology Data Exchange (ETDEWEB)

    Niehoerster, K.

    2001-02-01

    The geographic information system of the natural gas utility Ruhrgas AG is explained. It consists of a great variety of products for acquisition, up-dating and visualization of geographic data, as well as specific software solutions for customized applications. (orig./CB) [German] Das geographische Informationssystem der Ruhrgas AG wird ausfuehrlich beschrieben. Es besteht aus einer Vielzahl von Produkten zur Erfassung, Pflege und Visualisierung von geografischen Daten, sowie aus spezifischen Softwareloesungen fuer Kundenanwendungen. (orig./CB)

  9. NUCLA Circulating Atmospheric Fluidiz