WorldWideScience

Sample records for distribution primary circuits

  1. Temperature distribution in the Temelin NPP primary circuit piping

    International Nuclear Information System (INIS)

    Blaha, V.; Maca, K.; Kodl, P.; Kroj, L.

    2004-01-01

    Temperature non-homogeneity in the VVER 1000 reactor primary piping hot legs was detected during the commissioning of Temelin units 1 and 2. A quantification of temperature differences was carried out and explanation of its causes was presented. Mathematical analysis of the effect was carried out using the PHOENICS 3.4 code, and the results were processed graphically by means of a post processor PHOTON and by means of a user program allowing statistic evaluation of temperature profiles at the core outlet and in the area of the temperature-measurement pits. The coolant temperatures in the core area increased gradually following the given radial and axial distribution of output from the inlet temperature of 288.1 degC to 315-331 degC at the core outlet. The temperature profile was balanced and in the IO piping in the area of temperature-measurement pits the difference of the maximum and minimum temperature value was approx. 1 degC according to the calculation. The temperature field shape is mainly determined by the radial distribution of the core output. The mean outlet temperature from the core weighted through mass flow is determined by the flow through the core and by the total output. The calculated temperature span at the core outlet in the range of 315 - 331 degC corresponded well with the measured values during the operation. The values were in the range of 310-333 degC, however, the in-core thermocouple inaccuracy should also be taken into consideration. On the other hand, the temperature span in the area of temperature-measurement pits was actually about 4 times higher than the calculated temperature (observed: 4 degC as against the calculated 1 degC). A good agreement was reached between the analysis results and the actual condition of the nuclear unit in the area of the core outlet. (P.A.)

  2. BR-5 primary circuit decontamination

    International Nuclear Information System (INIS)

    Efimov, I.A.; Nikulin, M.P.; Smirnov-Averin, A.P.; Tymosh, B.S.; Shereshkov, V.S.

    1976-01-01

    Results and methodology of steam-water and acid decontamination of the primary coolant circuit SBR-5 reactor in 1971 are discussed. Regeneration process in a cold trap of the primary coolant circuit is discussed

  3. Computerized procedure for protection coordination in distribution primary circuits; Procedimiento computarizado para coordinacion de protecciones en circuitos primarios de distribucion

    Energy Technology Data Exchange (ETDEWEB)

    Carrillo, Victor M; Velazquez Sanchez, Raul [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1987-12-31

    Nowadays, the method employed to study the protection coordination are based in the hand outlining of curves time- current and in the visual comparison in log sheets. Due to the large amount of distribution circuits, the engineer makes a considerable effort to perform this type of studies, which besides are routinist and time consuming. In this article a program for the computer aided design for the protection coordination in primary distribution circuits is presented. Such a program -carried out in the Transmission and Distribution Department of the Power Systems Division of the Instituto de Investigaciones Electricas (IIE)- substitutes in an efficient manner, the manual procedures that are performed in the protection coordination studies. The coordination principles, suggested by the equipment manufacturers, were respected, trying, at the same time, to keep the procedures of the Comision Federal de Electricidad personnel (CFE) emerged from the field experience. The algorithm basically consists of an iterative process in the selection of the adjustments taking as a reference the of three-phase short- circuit and of phase to ground, values, as well as the operating times. [Espanol] Actualmente, los metodos que se emplean para estudiar la coordinacion de protecciones se basan en el trazado manual de curvas de tiempo-corriente y en la comparacion visual sobre hojas logaritmicas. Debido a la gran cantidad de circuitos de distribucion, el ingeniero hace un esfuerzo considerable para realizar este tipo de estudios, los que ademas, son rutinarios y tardados. En este articulo, se presenta un programa para el diseno asistido por computadora del proceso de coordinacion de protecciones en circuitos primarios de distribucion. Dicho programa -realizado en el Departamento de Transmision y Distribucion, de la Division de Sistemas de Potencia, del Instituto de Investigaciones Electricas (IIE)- sustituye de manera eficaz los procedimientos manuales que se efectuan en los estudios

  4. Computerized procedure for protection coordination in distribution primary circuits; Procedimiento computarizado para coordinacion de protecciones en circuitos primarios de distribucion

    Energy Technology Data Exchange (ETDEWEB)

    Carrillo, Victor M.; Velazquez Sanchez, Raul [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1986-12-31

    Nowadays, the method employed to study the protection coordination are based in the hand outlining of curves time- current and in the visual comparison in log sheets. Due to the large amount of distribution circuits, the engineer makes a considerable effort to perform this type of studies, which besides are routinist and time consuming. In this article a program for the computer aided design for the protection coordination in primary distribution circuits is presented. Such a program -carried out in the Transmission and Distribution Department of the Power Systems Division of the Instituto de Investigaciones Electricas (IIE)- substitutes in an efficient manner, the manual procedures that are performed in the protection coordination studies. The coordination principles, suggested by the equipment manufacturers, were respected, trying, at the same time, to keep the procedures of the Comision Federal de Electricidad personnel (CFE) emerged from the field experience. The algorithm basically consists of an iterative process in the selection of the adjustments taking as a reference the of three-phase short- circuit and of phase to ground, values, as well as the operating times. [Espanol] Actualmente, los metodos que se emplean para estudiar la coordinacion de protecciones se basan en el trazado manual de curvas de tiempo-corriente y en la comparacion visual sobre hojas logaritmicas. Debido a la gran cantidad de circuitos de distribucion, el ingeniero hace un esfuerzo considerable para realizar este tipo de estudios, los que ademas, son rutinarios y tardados. En este articulo, se presenta un programa para el diseno asistido por computadora del proceso de coordinacion de protecciones en circuitos primarios de distribucion. Dicho programa -realizado en el Departamento de Transmision y Distribucion, de la Division de Sistemas de Potencia, del Instituto de Investigaciones Electricas (IIE)- sustituye de manera eficaz los procedimientos manuales que se efectuan en los estudios

  5. Computation of fission product distribution in core and primary circuit of a high temperature reactor during normal operation

    International Nuclear Information System (INIS)

    Mattke, U.H.

    1991-08-01

    The fission product release during normal operation from the core of a high temperature reactor is well known to be very low. A HTR-Modul-reactor with a reduced power of 170 MW th is examined under the aspect whether the contamination with Cs-137 as most important nuclide will be so low that a helium turbine in the primary circuit is possible. The program SPTRAN is the tool for the computations and siumlations of fission product transport in HTRs. The program initially developed for computations of accident events has been enlarged for computing the fission product transport under the conditions of normal operation. The theoretical basis, the used programs and data basis are presented followed by the results of the computations. These results are explained and discussed; moreover the consequences and future possibilities of development are shown. (orig./HP) [de

  6. Solubility of cobalt in primary circuit solutions

    International Nuclear Information System (INIS)

    Lambert, I.; Joyer, F.

    1992-01-01

    The solubility of cobalt ferrite (CoFe 2 O 4 ) was measured in PWR primary circuit conditions, in the temperature range 250-350 deg C, and the results were compared with the ones obtained on magnetite and nickel ferrite. As in the former cases, it was found that, in the prevailing primary circuit conditions, the solubility of the cobalt ferrite was minimum at temperatures around 300 deg C, for cobalt as well as for iron. The equilibrium iron concentration is significantly lower than in the case of magnetite. The results are discussed in relation with the POTHY code, based only on thermodynamic laws and data, used for the prediction of the primary circuit chemistry

  7. Components of the primary circuit of LWRs

    International Nuclear Information System (INIS)

    1980-01-01

    This standard is to be applied to components made of metallic materials, operated at design temperatures of up to 673 K (400 C). The primary circuit as the pressure containment of the reactor coolant comprises: Reactor pressure vessel (without internals), steam generator (primary loop), pressurizer, reactor coolant pump housing, interconnecting pipings between the components mentioned above and appropriate various valve and instrument casings, pipings branding from the above components and interconnecting pipings, including the appropriate instrument casings, up to and including the first isolating valve, pressure shielding of control rod drives. (orig.) [de

  8. Primary coolant circuits in FBR type reactors

    International Nuclear Information System (INIS)

    Kutani, Masushiro.

    1985-01-01

    Purpose: To eliminate the requirement of a pump for the forcive circulation of primary coolants and avoid the manufacturing difficulty of equipments. Constitution: In primary coolant circuits of an LMFBR type reactor having a recycling path forming a closed loop between a reactor core and a heat exchanger, coolants recycled through the recycling path are made of a magnetic fluid comprising liquid sodium incorporated with fine magnetic powder, and an electromagnet is disposed to the downstream of the heat exchanger. In the above-mentioned structure, since the magnetic fluid as the primary coolants losses its magnetic property when heated in the reactor core but recovers the property at a lower temperature after the completion of the heat exchange, the magnetic fluid can forcively be flown through the recycling path under the effect of the electromagnet disposed to the down stream of the heat exchanger to thereby forcively recycle the primary coolants. (Kawakami, Y.)

  9. Simplified model of a PWR primary circuit

    International Nuclear Information System (INIS)

    Souza, A.L.; Faya, A.J.G.

    1988-07-01

    The computer program RENUR was developed to perform a very simplified simulation of a typical PWR primary circuit. The program has mathematical models for the thermal-hydraulics of the reactor core and the pressurizer, the rest of the circuit being treated as a single volume. Heat conduction in the fuel rod is analyzed by a nodal model. Average and hot channels are treated so that bulk response of the core and DNBR can be evaluated. A homogenenous model is employed in the pressurizer. Results are presented for a steady-state situation as well as for a loss of load transient. Agreement with the results of more elaborate computer codes is good with substantial reduction in computer costs. (author) [pt

  10. Short circuit protection for a power distribution system

    Science.gov (United States)

    Owen, J. R., III

    1969-01-01

    Sensing circuit detects when the output from a matrix is present and when it should be present. The circuit provides short circuit protection for a power distribution system where the selection of the driven load is accomplished by digital logic.

  11. Volumetric and chemical control auxiliary circuit for a PWR primary circuit

    International Nuclear Information System (INIS)

    Costes, D.

    1990-01-01

    The volumetric and chemical control circuit has an expansion tank with at least one water-steam chamber connected to the primary circuit by a sampling pipe and a reinjection pipe. The sampling pipe feeds jet pumps controlled by valves. An action on these valves and pumps regulates the volume of the water in the primary circuit. A safety pipe controlled by a flap automatically injects water from the chamber into the primary circuit in case of ruptures. The auxiliary circuit has also systems for purifying the water and controlling the boric acid and hydrogen content [fr

  12. 29 CFR 1915.181 - Electrical circuits and distribution boards.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Electrical circuits and distribution boards. 1915.181... Electrical Machinery § 1915.181 Electrical circuits and distribution boards. (a) The provisions of this... employee is permitted to work on an electrical circuit, except when the circuit must remain energized for...

  13. Fission and corrosion products behavior in primary circuits of LMFBR's

    International Nuclear Information System (INIS)

    Feuerstein, H.; Thorley, A.W.

    1987-08-01

    Most of the 20 presented papers report items belonging to more than one session. The equipment results of primary circuits of LMFBR's relative to corrosion and fission products, release and chemistry of fuel, measurement techniques and analytical procedures of sodium sampling, difficulties with radionuclides and particles, reactor experiences with EBR-II, FFTF, BR10, BOR60, BN350, BN600, JOYO, and KNK-II, DFR, PFR, RAPSODIE, PHENIX, and SUPERPHENIX, and at least the verification of codes for calculation models of radioactive products accumulation and distribution are described. All 20 papers presented at the meeting are separately indexed in the database. (DG)

  14. Experimental investigation of processes in primary circuit relief system

    International Nuclear Information System (INIS)

    Tomas, Z.; Simo, T.; Konecny, A.

    1989-01-01

    The protective condenser (direct contact condenser) is one of the basic components of the primary circuit relief system of WWER power plants. The steam flowing from the surge tank through relief valves into the subcooled water condensates in the protective condenser vessel. Two simple physical models were designed and constructed for investigation of bubbling through (contact condensation). An experimental program was performed with the aim of determining the distribution of temperatures in the axis of the steam jet and its vicinity, determining the velocity field of water into vicinity of steam jets, observing the geometrical shape of jets and their interaction and determining important values for mathematical model. (orig.)

  15. Method of decontaminating primary coolant circuits

    International Nuclear Information System (INIS)

    Ishibashi, Masaru; Sumi, Masao.

    1981-01-01

    Purpose: To eliminate hard contaminated layers as well as soft contaminated layers without injuring substrate materials, upon decontamination of radiation contaminated portions in equipments and pipeways constituting primary coolant circuits. Constitution: High pressure water from a high pressure pump is jetted out from the nozzle of a spray gun to the radiation contaminated portions in equipments, for example, to the surface of water chamber in a vapor evaporator. High pressure pure water or aqueous boric acid is jetted out from the periphery and boric oxide particles (of about 1 - 100 μ particle size) are jetted out from the center of the nozzle of the spray gun. The particles (blasting material) jetted out together with the high pressure water impinge on the contaminated surfaces to remove the contaminated layers. Upon impingement, the high pressure water acts as the shock absorber for the blasting material and, after the impingement, it flows down to the bottom of the water chamber, and the blasting material is dissolved in the high pressure water. (Horiuchi, T.)

  16. Optimizing Teleportation Cost in Distributed Quantum Circuits

    Science.gov (United States)

    Zomorodi-Moghadam, Mariam; Houshmand, Mahboobeh; Houshmand, Monireh

    2018-03-01

    The presented work provides a procedure for optimizing the communication cost of a distributed quantum circuit (DQC) in terms of the number of qubit teleportations. Because of technology limitations which do not allow large quantum computers to work as a single processing element, distributed quantum computation is an appropriate solution to overcome this difficulty. Previous studies have applied ad-hoc solutions to distribute a quantum system for special cases and applications. In this study, a general approach is proposed to optimize the number of teleportations for a DQC consisting of two spatially separated and long-distance quantum subsystems. To this end, different configurations of locations for executing gates whose qubits are in distinct subsystems are considered and for each of these configurations, the proposed algorithm is run to find the minimum number of required teleportations. Finally, the configuration which leads to the minimum number of teleportations is reported. The proposed method can be used as an automated procedure to find the configuration with the optimal communication cost for the DQC. This cost can be used as a basic measure of the communication cost for future works in the distributed quantum circuits.

  17. Developing equivalent circuits for radial distribution networks

    Energy Technology Data Exchange (ETDEWEB)

    Prada, Ricardo; Coelho, Agnelo; Rodrigues, Anselmo [Catholic University of Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. of Electrical Engineering], Emails: prada@ele.puc-rio.br, agnelo@ele.puc-rio.br, nebulok_99@yahoo.com; Silva, Maria da Guia da [Federal University of Maranhao, Sao Luiz, MA (Brazil). Dept. of Electrical Engineering

    2009-07-01

    This paper presents a method for evaluating External Equivalent in Electric Distribution Networks (EDN).The proposed method has as its main objectives the reduction of the computational costs in distribution network reconfiguration, investigation of the optimal allocation of banks of capacitors, investigation of the allocation of distributed generation, etc. In these sorts of problems a large number of alternative projects must be assessed in order to identify the optimal solution. The optimal solution comes up with the voltage level in the load points within specified limits. Consequently, the EDN must retain the external network load points but without major increasing in the dimension of the equivalent circuit. The proposed method has been tested and validated in a substation of the Electricity Utility of Maranhao - CEMAR, in Brazil. (author)

  18. Current distribution characteristics of superconducting parallel circuits

    International Nuclear Information System (INIS)

    Mori, K.; Suzuki, Y.; Hara, N.; Kitamura, M.; Tominaka, T.

    1994-01-01

    In order to increase the current carrying capacity of the current path of the superconducting magnet system, the portion of parallel circuits such as insulated multi-strand cables or parallel persistent current switches (PCS) are made. In superconducting parallel circuits of an insulated multi-strand cable or a parallel persistent current switch (PCS), the current distribution during the current sweep, the persistent mode, and the quench process were investigated. In order to measure the current distribution, two methods were used. (1) Each strand was surrounded with a pure iron core with the air gap. In the air gap, a Hall probe was located. The accuracy of this method was deteriorated by the magnetic hysteresis of iron. (2) The Rogowski coil without iron was used for the current measurement of each path in a 4-parallel PCS. As a result, it was shown that the current distribution characteristics of a parallel PCS is very similar to that of an insulated multi-strand cable for the quench process

  19. Radioisotopes in the primary circuit of a fast reactor

    International Nuclear Information System (INIS)

    Berlin, M.; Cauvin, M.

    1976-01-01

    In the frame of the research performed to understand the behaviour of the radioactive isotopes of iodine in the primary coolant circuit of fast reactor, a simple theoretical model is proposed. Results concerning PHENIX and RAPSODIE are given

  20. Superconducting power distribution structure for integrated circuits

    International Nuclear Information System (INIS)

    Ruby, R.C.

    1991-01-01

    This patent describes a superconducting power distribution structure for an integrated circuit. It comprises a first superconducting capacitor plate; a second superconducting capacitor plate provided with electrical isolation means within the second capacitor plate; dielectric means separating the first capacitor plate from the second capacitor plate; first via means coupled at a first end to the first capacitor plate and extending through the dielectric and the electrical isolation means of the second capacitor plate; first contact means coupled to a second end of the first via means; and second contact means coupled to the second capacitor plate such that the first contact means and the second contact means are accessible from the same side of the second capacitor plate

  1. Resin intrusion into the primary circuit of NPP Jaslovske Bohunice V-1

    International Nuclear Information System (INIS)

    Grezdo, O.; Mraz, V.

    2005-01-01

    During the refueling at the first unit of Bohunice NPP in 2005 a lot of sediment was found on the upper storage rack. This sediment was identification as a filter resin. Resin was found in most of the fuel assemblies, pipes and tanks of the primary circuit and his auxiliary systems. Resin producer and WANO network was contacted in order to get information about similar events. Management of Bohunice NPP made a decision that primary circuit, fuel assemblies and auxiliary systems have to be cleaned. Subsequent cleaning extended outage by 31 days. This paper summarizes causes, existing consequences and corrective actions. Accent was put on the hydraulic characteristics of the primary circuit measurement, power distribution core monitoring and the primary circuit water quality verification (Authors)

  2. Primary circuit water chemistry during shutdown period at Kalinin NPP

    International Nuclear Information System (INIS)

    Gorbatenko, S.; Otchenashev, G.; Yurmanov, V.

    2005-01-01

    The primary circuit water chemistry feature at Kalinin NPP is using of special up-dated regime during the period of unit shutdown for refueling. The main objective of up-dated regime is removing from the circuit long time living corrosion products on SVO-2 ion exchange filters with the purpose of dose rates reduction from the equipment and in such a way reduction of maintenance personnel overexposure. (N.T.)

  3. Criteria for the selection of PEC primary circuit structural material

    International Nuclear Information System (INIS)

    Antoni, R.; Brunori, G.; Maesa, S.; Scibona, G.; Tomassetti, G.

    1977-01-01

    The choice of the structural materials is generally a compromise between the project requirements, the characteristics (mechanical and environmental) of the materials and the available technology to construct the various parts of the components. The criteria of selection of structural materials for the primary circuit of fast reactor are reported. The criteria concern both general and utilization aspects

  4. Ammonia role in WWER primary circuit water chemistry optimization

    International Nuclear Information System (INIS)

    Kritskij, V.G.; Stjagkin, P.S.; Chvedova, M.N.; Slobodov, A.A.

    1999-01-01

    Ammonia influence on iron crud's solubility at 300 deg. C and different relations of boric acid and alkaline cation sum are considered. Reduction of dose rate on WWER-440 steam generators at average ammonia concentration increasing is empirically explained. Practical recommendations on optimization of WWER primary circuit water chemistry are given. (author)

  5. Integrated Power Flow and Short Circuit Calculation Method for Distribution Network with Inverter Based Distributed Generation

    OpenAIRE

    Yang, Shan; Tong, Xiangqian

    2016-01-01

    Power flow calculation and short circuit calculation are the basis of theoretical research for distribution network with inverter based distributed generation. The similarity of equivalent model for inverter based distributed generation during normal and fault conditions of distribution network and the differences between power flow and short circuit calculation are analyzed in this paper. Then an integrated power flow and short circuit calculation method for distribution network with inverte...

  6. The primary circuit of the dragon high temperature reactor experiment

    International Nuclear Information System (INIS)

    Simon, R.

    2005-01-01

    The 20 MWth Dragon Reactor Experiment was the first HTGR (High Temperature Gas-cooled Reactor) with coated particle fuel. Its purpose was to test fuel and materials for the High Temperature Reactor programmes pursued in Europe 40 years ago. This paper describes the design and construction of the primary (helium) circuit. It summarizes the main design objectives, lists the performance data and explains the flow paths of the heat removal and helium purification systems. The principal circuit accidents postulated are discussed and the choice of the main construction materials is given. (author)

  7. Fission product behaviour in the primary circuit of an HTR

    International Nuclear Information System (INIS)

    Decken, C.B. von der; Iniotakis, N.

    1981-01-01

    The knowledge of fission product behaviour in the primary circuit of a High Temperature Reactor (HTR) is an essential requirement for the estimations of the availability of the reactor plant in normal operation, of the hazards to personnel during inspection and repair and of the potential danger to the environment from severe accidents. On the basis of the theoretical and experimental results obtained at the ''Institute for Reactor Components'' of the KFA Juelich /1/,/2/ the transport- and deposition behaviour of the fission- and activation products in the primary circuit of the PNP-500 reference plant has been investigated thoroughly. Special work had been done to quantify the uncertainties of the investigations and to calculate or estimate the dose rate level at different components of the primary cooling circuit. The contamination and the dose rate level in the inspection gap in the reactor pressure vessel is discussed in detail. For these investigations in particular the surface structure and the composition of the material, the chemical state of the fission products in the cooling gas, the composition of the cooling gas and the influence of dust on the transport- and deposition behaviour of the fission products have been taken into account. The investigations have been limited to the nuclides Ag-110m; Cs-134 and Cs-137

  8. Components of the LWR primary circuit. Pt. 2

    International Nuclear Information System (INIS)

    1984-01-01

    This standard is to be applied to components made of metallic materials, operated at design temperatures of up to 673 K (400 0 C). The primary circuit as the pressure containment of the reactor coolant comprises: Reactor pressure vessel (without internals), steam generator (primary loop), pressurizer, reactor coolant pump housing, interconnecting pipings between the components mentioned above and appropriate various valve and instrument casings, pipings branding from the above components and interconnecting pipings, including the appropriate instrument casings, up to and including the first isolating valve, pressure shielding of control rod drives. (orig.) [de

  9. Corrosion products in the primary circuits of PWRs

    International Nuclear Information System (INIS)

    Darras, R.

    1983-01-01

    The characteristics of PWR primary circuits are recalled, particularly the chemical specifications of the medium and the various materials used (austenitic steel, nickel alloys, cobalt-based alloys and zirconium alloys). The behaviour of these materials as regards general corrosion in nominal and transient conditions is then outlined briefly, special emphasis being laid on the effect of the determining parameters on the quantity of corrosion products formed. The release of the latter into the primary coolant is caused by two main processes: solubilization and erosion. Particular attention was given therefore to the laws governing the solubility of the oxides involved, especially as a function of temperature and pH. Erosion, or release in the form of solid particles, is relatively severe during transient events. As these corrosion products are then carried through all circuits, they cause deposits to form in favourable places on the walls as a result either of precipitation of soluble species or of sedimentation followed by consolidation of suspended particles. The presence of corrosion products in the primary circuits creates a particular impact since they become radioactive as they pass through the core and especially when they remain in it in the form of deposits; as a result, the products are capable of contaminating the entire system. Finally, although long-term reliability is obviously an essential condition for materials developed, attention must also be given to problems associated with a build-up of corrosion products in the cooling circuits and efforts made to minimize them. To that end, a number of precautions are recommended, and various remedies can be applied: selecting materials which are not readily activated, keeping structures clean, purifying fluids properly, restricting solubilization and precipitation, and perhaps, periodic decontamination. (author)

  10. Simplified model of a PWR primary coolant circuit

    International Nuclear Information System (INIS)

    Souza, A.L. de; Faya, A.J.G.

    1988-01-01

    The computer program RENUR was developed to perform a very simplified simulation of a typical PWR primary circuit. The program has mathematical models for the thermal-hydraulics of the reactor core and the pressurizer, the rest of the circuit being treated as a single volume. Heat conduction in the fuel rod is analysed by a nodal model. Average and hot channels are treated so that the bulk response of the core and DNBR can be evaluated. A Homogenenous model is employed in the pressurizer. Results are presented for a steady-state situation as well as for a loss of load transient. Agreement with the results of more elaborate computer codes is good with substantial reduction in computer costs. (author) [pt

  11. Monitoring of primary circuit and reactor of NPP A-1

    International Nuclear Information System (INIS)

    Prazska, M.; Majersky, M.; Rezbarik, J.; Sekely, S.; Vozarik, P.; Walthery, R.; Stuller, P.

    2005-01-01

    Nuclear Power Plant A-1 in Jaslovske Bohunice was commissioned in 1972. Heavy water moderated, carbon dioxide cooled channel type reactor was shut down after two accidents in 1977. During more serious second accident, the reduced coolant flow caused local overheating of the fuel and consequent damage/melting of the fuel channel. Both accidents had led to the damage of several fuel assemblies with extensive local damage of fuel claddings. As a consequence, the main cooling circuit was significantly contaminated by fission products and long-life alpha nuclides. The detailed monitoring of dose rates, smearable contamination and sampling of contamination was performed. Extended monitoring in reacto vessel, primary circuit pipes, turbo-compressors, steam generators, main valves, gas tanks and also heavy water system with collectors, coolers, distilling and purification station, pumps and valves was done. Appropriate devices and procedures for the monitoring and examination of the installations were prepared and applied. Obtained results will serve for the future planning of the decontamination and decommissioning works. The 3-D model of the reactor that had been developed as part of this Project proved invaluable for orientation, visualisation, planning and analysis of results. Dose rates were measured in the technological channels from the reactor hall floor to the bottom of the hot gas chamber in decrements of 1 m and 0.5 m. The highest absolute values of dose rates were found in channels located in the middle of the reactor (up to 1900 mGy/h in the active zone region). It is estimated that the total contaminated area of primary circuit equipment (pipework, steam generators and turbo-compressors) is some 48 000 m 2 . It follows that the total gamma contamination is of the order of 10 14 to 10 15 Bq and total alpha contamination 10 11 to 10 13 Bq. The total amount of deposits in the gas circuit is about 14.3 tons. (authors)

  12. Study on radioactive corrosion products behaviour in primary circuits of JOYO

    International Nuclear Information System (INIS)

    Iizawa, Katsuyuki; Suzuki, Soju; Tamura, Masaaki; Seki, Seiichi; Hikichi, Takayoshi

    1987-01-01

    Radioactive CP deposition and distribution, and the resulting radiation fields along the JOYO primary circuit piping have been measured. The measurement results have been compared with calculations for estimating radioactive CP behaviour and the resulting radiation fields in an LMFBR primary circuit using a computer code which is named PSYCHE. The deposited radioactivity of CPs calculated by using PSYCHE agreed well with the measured results within a factor of 0.5-2. The gamma dose rate distribution calculated from the PSYCHE results reproduced measured values within a factor of 0.6-2 over the piping system, using the JOANDARC modification of the QAD-CG code. Using these verified codes, a prediction of radiation levels for future plant operation, and an evaluation of methods for the reduction of radioactive CPs have been conducted. (orig./DG)

  13. Thermal hydraulic tradeoffs in the design of IRIS primary circuit

    International Nuclear Information System (INIS)

    Oriani, L.; Lombardi, C.; Ricotti, M.E.; Paramonov, D.; Carelli, M.; Conway, L.

    2001-01-01

    IRIS (International Reactor Innovative and Secure) is currently being developed by an international consortium, led by Westinghouse and including universities. In order to achieve high level of safety, reduce complexity and capital cost, and enhance proliferation resistance, an integral primary circuit configuration has been selected. The integral configuration (the core, steam generators, coolant pumps, pressurizer and control rods are all contained within the reactor vessel) has no loop piping and thereby eliminates the possibility of large loss of coolant accidents. If the reactor vessel and components are designed for a very high level of natural circulation, which is promoted by an integral design, the consequence of loss of flow accidents can be significantly reduced or even completely eliminated. Core and integral primary circuit design optimization has been performed using the OSCAR computer code, a specialized tool for the analyses of the IRIS primary system developed at POLIMI. Results of trade-off studies of various in-vessel configurations explored to achieve tight packaging and high serviceability and/or replacement of components such as steam generators and pumps are reported. Effects of changes in secondary side parameters and steam generator design on system efficiency were explored together with the optimization of the vessel and steam generator dimensions and costs. The aim of the trade-off analyses was to limit the design space, and select a reference configuration for the IRIS reactor. (author)

  14. Substitution of cobalt alloying in PWR primary circuit gate valves

    International Nuclear Information System (INIS)

    Cachon, L.; Sudreau, F.; Brunel, L.

    1995-01-01

    The object of this study is qualify cobalt-free alternative alloys for valve applications. This paper focus on tribological characterization of numerous coatings is done by using the first one, of a classical type. Then tests are performed with the second one which simulates solicitations supported by gate valves in primary circuit of PWR. 35% Ni-Cr - 65% Cr 3 C 2 coating, deposited by detonation gun technology, gives us hope to find a substitute of Stelite 6. (author). 5 refs., 16 figs., 2 tabs

  15. A high-precision synchronization circuit for clock distribution

    International Nuclear Information System (INIS)

    Lu Chong; Tan Hongzhou; Duan Zhikui; Ding Yi

    2015-01-01

    In this paper, a novel structure of a high-precision synchronization circuit, HPSC, using interleaved delay units and a dynamic compensation circuit is proposed. HPSCs are designed for synchronization of clock distribution networks in large-scale integrated circuits, where high-quality clocks are required. The application of a hybrid structure of a coarse delay line and dynamic compensation circuit performs roughly the alignment of the clock signal in two clock cycles, and finishes the fine tuning in the next three clock cycles with the phase error suppressed under 3.8 ps. The proposed circuit is implemented and fabricated using a SMIC 0.13 μm 1P6M process with a supply voltage at 1.2 V. The allowed operation frequency ranges from 200 to 800 MHz, and the duty cycle ranges between [20%, 80%]. The active area of the core circuits is 245 × 134 μm 2 , and the power consumption is 1.64 mW at 500 MHz. (paper)

  16. Effect of decontamination on nuclear power plant primary circuit materials

    International Nuclear Information System (INIS)

    Brezina, M.; Kupca, L.

    1991-01-01

    The effect of repeated decontamination on the properties of structural materials of the WWER-440 primary coolant circuit was examined. Three kinds of specimens of 08Kh18Ni10T steel were used for radioactivity-free laboratory experiments; they included material obtained from assembly additions to the V-2 nuclear power plant primary piping, and a sheet of the CSN 17247 steel. Various chemical, electrochemical and semi-dry electrochemical decontamination procedures were tested. Chemical decontamination was based on the conventional AP(20/5)-CITROX(20/20) procedure and its variants; NP-CITROX type procedures with various compositions were also employed. Solutions based on oxalic acid were tested for the electrochemical and semi-dry electrochemical decontamination. The results of measurements of mass losses of the surfaces, of changes in the corrosion resistance and in the mechanical properties of the materials due to repeated decontamination are summarized. (Z.S.). 12 figs., 1 tab., 8 refs

  17. Noise distribution of a peak track and hold circuit

    International Nuclear Information System (INIS)

    Seller, Paul; Hardie, Alec L.; Morrissey, Quentin

    2012-01-01

    Noise in linear electronic circuits is well characterised in terms of power spectral density in the frequency domain and the Normal probability density function in the time domain. For instance a charge preamplifier followed by a simple time independent pulse shaping circuit produces an output with a predictable, easily calculated Normal density function. By the Ergodic Principle this is true if the signal is sampled randomly in time or the experiment is run many times and measured at a fixed time after the circuit is released from reset. Apart from well defined cases, the time of the sample after release of reset does not affect the density function. If this signal is then passed through a peak track-and-hold circuit the situation is very different. The probability density function of the sampled signal is no longer Normal and the function changes with the time of the sample after release of reset. This density function can be classified by the Gumbel probability density function which characterises the Extreme Value Distribution of a defined number of Normally distributed values. The number of peaks in the signal is an important factor in the analysis. This issue is analysed theoretically and compared with a time domain noise simulation programme. This is then related to a real electronic circuit used for low-noise X-ray measurements and shows how the low-energy resolution of this system is significantly degraded when using a peak track-and-hold.

  18. Derivation of criteria for primary circuit activity in an HTGR

    International Nuclear Information System (INIS)

    Su, S.D.; Barsell, A.W.

    1980-11-01

    This paper derives specific criteria for the circulating and plateout activity in the primary circuit for a 2170-MW(t) high temperature gas-cooled reactor-gas turbine (HTGR-GT) plant. Results show that for a design basis, (1) the circulating activity should be limited to 14,000 Ci Kr-88 (a principal nuclide) to meet both offsite dose and containment access constraint during normal operation and depressurization accidents, and (2) the plateout inventories for those important nuclides affecting shutdown maintenance should not exceed 10,000 Ci Ag-110m, 45,000 Ci Cs-134 and 130,000 Ci Cs-137. This paper presents bases and methodology for deriving such criteria and compares them with light water reactors. 5 tables

  19. Behavior of stainless steels in pressurized water reactor primary circuits

    International Nuclear Information System (INIS)

    Féron, D.; Herms, E.; Tanguy, B.

    2012-01-01

    Stainless steels are widely used in primary circuits of pressurized water reactors (PWRs). Operating experience with the various grades of stainless steels over several decades of years has generally been excellent. Nevertheless, stress corrosion failures have been reported in few cases. Two main factors contributing to SCC susceptibility enhancement are investigated in this study: cold work and irradiation. Irradiation is involved in the stress corrosion cracking and corrosion of in-core reactor components in PWR environment. Irradiated assisted stress corrosion cracking (IASCC) is a complex and multi-physics phenomenon for which a predictive modeling able to describe initiation and/or propagation is not yet achieved. Experimentally, development of initiation smart tests and of in situ instrumentation, also in nuclear reactors, is an important axis in order to gain a better understanding of IASCC kinetics. A strong susceptibility for SCC of heavily cold worked austenitic stainless steels is evidenced in hydrogenated primary water typical of PWRs. It is shown that for a given cold-working procedure, SCC susceptibility of austenitic stainless steels materials increases with increasing cold-work. Results have shown also strong influences of the cold work on the oxide layer composition and of the maximum stress on the time to fracture.

  20. Feeding and purge systems of coolant primary circuit and coolant secondary circuit control of the I sup(123) target

    International Nuclear Information System (INIS)

    Almeida, G.L. de.

    1986-01-01

    The Radiation Protection Service of IEN (Brazilian-CNEN) detected three faults in sup(123)I target cooling system during operation process for producing sup(123)I: a) non hermetic vessel containing contaminated water from primary coolant circuit; possibility of increasing radioactivity in the vessel due to accumulation of contaminators in cooling water and; situation in region used for personnels to arrange and adjust equipments in nuclear physics area, to carried out maintenance of cyclotron and target coupling in irradiation room. The primary circuit was changed by secondary circuit for target coolant circulating through coil of tank, which receive weater from secondary circuit. This solution solved the three problems simultaneously. (M.C.K.)

  1. Integrated Power Flow and Short Circuit Calculation Method for Distribution Network with Inverter Based Distributed Generation

    Directory of Open Access Journals (Sweden)

    Shan Yang

    2016-01-01

    Full Text Available Power flow calculation and short circuit calculation are the basis of theoretical research for distribution network with inverter based distributed generation. The similarity of equivalent model for inverter based distributed generation during normal and fault conditions of distribution network and the differences between power flow and short circuit calculation are analyzed in this paper. Then an integrated power flow and short circuit calculation method for distribution network with inverter based distributed generation is proposed. The proposed method let the inverter based distributed generation be equivalent to Iθ bus, which makes it suitable to calculate the power flow of distribution network with a current limited inverter based distributed generation. And the low voltage ride through capability of inverter based distributed generation can be considered as well in this paper. Finally, some tests of power flow and short circuit current calculation are performed on a 33-bus distribution network. The calculated results from the proposed method in this paper are contrasted with those by the traditional method and the simulation method, whose results have verified the effectiveness of the integrated method suggested in this paper.

  2. Short circuit analysis of distribution system with integration of DG

    DEFF Research Database (Denmark)

    Su, Chi; Liu, Zhou; Chen, Zhe

    2014-01-01

    and as a result bring challenges to the network protection system. This problem has been frequently discussed in the literature, but mostly considering only the balanced fault situation. This paper presents an investigation on the influence of full converter based wind turbine (WT) integration on fault currents......Integration of distributed generation (DG) such as wind turbines into distribution system is increasing all around the world, because of the flexible and environmentally friendly characteristics. However, DG integration may change the pattern of the fault currents in the distribution system...... during both balanced and unbalanced faults. Major factors such as external grid short circuit power capacity, WT integration location, connection type of WT integration transformer are taken into account. In turn, the challenges brought to the protection system in the distribution network are presented...

  3. 30 CFR 77.501 - Electric distribution circuits and equipment; repair.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric distribution circuits and equipment... OF UNDERGROUND COAL MINES Electrical Equipment-General § 77.501 Electric distribution circuits and equipment; repair. No electrical work shall be performed on electric distribution circuits or equipment...

  4. Filtering device for primary coolant circuits in BWR type reactors

    International Nuclear Information System (INIS)

    Tajima, Fumio; Yamamoto, Tetsuo.

    1985-01-01

    Purpose: To obtain a filtering device with a large filtering area and requiring less space. Constitution: A condensate inlet for introducing condensates to be filtered of primary coolant circuits, a filtrate exit, a backwash water exit and a bent tube are disposed to a container, and a plurality of hollow thread membrane modules are suspended in the container. The condensates are caused to flow through the condensate inlet, filtered through the hollow thread membrane and then discharged from the filtrate exit. When the filtering treatment is proceeded to some extent, since solid contents captured in the hollow thread membranes are accumulated, a differential pressure is produced between the condensate inlet and the filtrate exit. When the differential pressure reaches a predetermined value, the backwash is conducted to discharge the liquid cleaning wastes through the backwash exit. The bent tube disposed to the container body is used for water and air draining. The hollow thread membranes are formed with porous resin such as of polyethylene. (Kawakami, Y.)

  5. Cognitive consilience: Primate non-primary neuroanatomical circuits underlying cognition

    Directory of Open Access Journals (Sweden)

    Soren Van Hout Solari

    2011-12-01

    Full Text Available Interactions between the cerebral cortex, thalamus, and basal ganglia form the basis ofcognitive information processing in the mammalian brain. Understanding the principles ofneuroanatomical organization in these structures is critical to understanding the functions theyperform and ultimately how the human brain works. We have manually distilled and synthesizedhundreds of primate neuroanatomy facts into a single interactive visualization. The resultingpicture represents the fundamental neuroanatomical blueprint upon which cognitive functionsmust be implemented. Within this framework we hypothesize and detail 7 functional circuitscorresponding to psychological perspectives on the brain: consolidated long-term declarativememory, short-term declarative memory, working memory/information processing, behavioralmemory selection, behavioral memory output, cognitive control, and cortical information flow regulation. Each circuit is described in terms of distinguishable neuronal groups including thecerebral isocortex (9 pyramidal neuronal groups, parahippocampal gyrus and hippocampus,thalamus (4 neuronal groups, basal ganglia (7 neuronal groups, metencephalon, basal forebrainand other subcortical nuclei. We focus on neuroanatomy related to primate non-primary corticalsystems to elucidate the basis underlying the distinct homotypical cognitive architecture. To dis-play the breadth of this review, we introduce a novel method of integrating and presenting datain multiple independent visualizations: an interactive website (www.cognitiveconsilience.comand standalone iPhone and iPad applications. With these tools we present a unique, annotatedview of neuroanatomical consilience (integration of knowledge.

  6. Draft of diagnostic techniques for primary coolant circuit facilities using control computer

    International Nuclear Information System (INIS)

    Suchy, R.; Procka, V.; Murin, V.; Rybarova, D.

    A method is proposed of in-service on-line diagnostics of primary circuit selected parts by means of a control computer. Computer processing will involve the measurements of neutron flux, pressure difference in pumps and in the core, and the vibrations of primary circuit mechanical parts. (H.S.)

  7. Engine Tune-Up Service. Unit 3: Primary Circuit. Review Exercise Book. Automotive Mechanics Curriculum.

    Science.gov (United States)

    Bacon, E. Miles

    This book of pretests and review exercises is designed to accompany the Engine Tune-Up Service Student Guide for Unit 3, Primary Circuit, available separately as CE 031 211. Focus of the exercises and pretests is testing the primary ignition circuit. Pretests and performance checklists are provided for each of the eight performance objectives…

  8. Engine Tune-Up Service. Unit 3: Primary Circuit. Student Guide. Automotive Mechanics Curriculum.

    Science.gov (United States)

    Bacon, E. Miles

    This student guide is for Unit 3, Primary Circuit, in the Engine Tune-Up Service portion of the Automotive Mechanics Curriculum. It deals with how to test the primary ignition circuit. A companion review exercise book and posttests are available separately as CE 031 212-213. An introduction tells how this unit fits into the total tune-up service,…

  9. Engine Tune-Up Service. Unit 3: Primary Circuit. Posttests. Automotive Mechanics Curriculum.

    Science.gov (United States)

    Morse, David T.

    This book of posttests is designed to accompany the Engine Tune-Up Service Student Guide for Unit 3, Primary Circuit, available separately as CE 031 211. Focus of the posttests is setting the primary ignition circuit. One multiple choice posttest is provided, covering the eight performance objectives contained in the unit. (No answer key is…

  10. Primary circuit iodine model addition to IMPAIR-3

    Energy Technology Data Exchange (ETDEWEB)

    Osetek, D J; Louie, D L.Y. [Los Alamos Technical Associates, Inc., Albuquerque, NM (United States); Guntay, S; Cripps, R [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-12-01

    As part of a continuing effort to provide the U.S. Department of Energy (DOE) Advanced Reactor Severe Accident Program (ARSAP) with complete iodine analysis capability, a task was undertaken to expand the modeling of IMPAIR-3, an iodine chemistry code. The expanded code will enable the DOE to include detailed iodine behavior in the assessment of severe accident source terms used in the licensing of U.S. Advanced Light Water Reactors (ALWRs). IMPAIR-3 was developed at the Paul Scherrer Institute (PSI), Switzerland, and has been used by ARSAP for the past two years to analyze containment iodine chemistry for ALWR source term analyses. IMPAIR-3 is primarily a containment code but the iodine chemistry inside the primary circuit (the Reactor Coolant System or RCS) may influence the iodine species released into the the containment; therefore, a RCS iodine chemistry model must be implemented in IMPAIR-3 to ensure thorough source term analysis. The ARSAP source term team and the PSI IMPAIR-3 developers are working together to accomplish this task. This cooperation is divided into two phases. Phase I, taking place in 1996, involves developing a stand-alone RCS iodine chemistry program called IMPRCS (IMPAIR -Reactor Coolant System). This program models a number of the chemical and physical processes of iodine that are thought to be important at conditions of high temperature and pressure in the RCS. In Phase II, which is tentatively scheduled for 1997, IMPRCS will be implemented as a subroutine in IMPAIR-3. To ensure an efficient calculation, an interface/tracking system will be developed to control the use of the RCS model from the containment model. These two models will be interfaced in such a way that once the iodine is released from the RCS, it will no longer be tracked by the RCS model but will be tracked by the containment model. All RCS thermal-hydraulic parameters will be provided by other codes. (author) figs., tabs., refs.

  11. Cellular complexity in subcortical white matter: a distributed control circuit?

    Science.gov (United States)

    Colombo, Jorge A

    2018-03-01

    The subcortical white matter (SWM) has been traditionally considered as a site for passive-neutral-information transfer through cerebral cortex association and projection fibers. Yet, the presence of subcortical neuronal and glial "interstitial" cells expressing immunolabelled neurotransmitters/neuromodulators and synaptic vesicular proteins, and recent immunohistochemical and electrophysiological observations on the rat visual cortex as well as interactive regulation of myelinating processes support the possibility that SWM nests subcortical, regionally variable, distributed neuronal-glial circuits, that could influence information transfer. Their hypothetical involvement in regulating the timing and signal transfer probability at the SWM axonal components ought to be considered and experimentally analysed. Thus, the "interstitial" neuronal cells-associated with local glial cells-traditionally considered to be vestigial and functionally inert under normal conditions, they may well turn to be critical in regulating information transfer at the SWM.

  12. Thermodynamics and the transport of corrosion products in PWR primary circuits

    International Nuclear Information System (INIS)

    Turner, D.J.

    1992-01-01

    It is argued that practically useful models for the activation, transport and deposition of corrosion products in PWR primary circuits can only be produced on the basis of an improved understanding of the chemical processes which control them. In particular, if a model is to make reliable predictions it is essential that its thermodynamic basis be sound. This is not the case with most current models which employ the erroneous concept of a corrosion product 'solubility'. In addition to the misuse of this term, other complications are discussed. These include the need to take account of the consequences of Gibbs' phase rule and the fact that, for mixed spinels, neither the concept of a thermodynamic solubility nor of a solubility product is valid. There is no reason to believe that measured apparent solubilities of nickel ferrites or spinel mixtures containing cobalt can give any direct guidance on the direction of transport of Ni or Co in PWR primary circuits. This is more likely to be determined by the distribution of stable and unstable ferrites and chromites than by any temperature coefficient of apparent solubility. Most of the transport of Ni and Co into and out of the core probably occurs as a consequence of either chemical or mechanical transients. Most important is likely to be the oxidative destruction and subsequent re-precipitation of chromites which occurs as a consequence of the oxygenated conditions employed during plant shutdown. (author)

  13. Principal working group 3 on primary circuit integrity

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-12-31

    The main themes of this conference (13 papers) are: operating experience on leakages and failures in nuclear power plant piping, coolant circuits and steam generator tubes, probabilistic estimation and risk assessment, system failure analysis, leakage events and frequency, leak rate models and crack propagation mechanics, damage mechanisms and rupture probability.

  14. Helium impurities in a PNP-primary coolant circuit

    International Nuclear Information System (INIS)

    Reif, M.

    1981-01-01

    The concentration of impurities to be expected have been defined in consideration of recent findings concerning the rates of infiltration and formation and the reaction mechanisms of the impurity components in the circuit. The data obtained correspond with the requirements on the metallic high-temperature components as well as with the requirements of limited graphite corrosion. (DG) [de

  15. Principal working group 3 on primary circuit integrity

    International Nuclear Information System (INIS)

    1992-01-01

    The main themes of this conference (13 papers) are: operating experience on leakages and failures in nuclear power plant piping, coolant circuits and steam generator tubes, probabilistic estimation and risk assessment, system failure analysis, leakage events and frequency, leak rate models and crack propagation mechanics, damage mechanisms and rupture probability

  16. Manipulator techniques and problems of their application in primary circuit maintenance

    International Nuclear Information System (INIS)

    Kertscher, F.; Popp, P.

    1985-01-01

    The fundamental structure and specifications of manipulators (in particular of industrial robots) are presented in order to derive the application conditions and fields for manipulators in primary circuit maintenance. The necessity of applying process-specific manipulator technique in the primary circuit maintenance is based on nuclear safety requirements and on decreasing of the radiation exposure of maintenance personnel. Synchronous manipulators and industrial robots are the types of manipulators used in materials testing, repairing and scrapping. The technical requirements of manipulators are discussed

  17. Integrated equipment for increasing and maintaining coolant pressure in primary circuit of PWR nuclear power plant

    International Nuclear Information System (INIS)

    Sykora, D.

    1986-01-01

    An open heat pump circuit is claimed connected to the primary circuit. The pump circuit consists of a steam pressurizer with a built-in steam distributor, a compressor, an expander, a reducing valve, an auxiliary pump, and of water and steam pipes. The operation is described and a block diagram is shown of integrated equipment for increasing and maintaining pressure in the nuclear power plant primary circuit. The appropriate entropy diagram is also shown. The advantage of the open pump circuit consists in reducing the electric power input and electric power consumption for the steam pressurizers, removing entropy loss in heat transfer with high temperature gradient, in the possibility of inserting, between the expander and the auxiliary pump, a primary circuit coolant treatment station, in simplified design and manufacture of the high-pressure steam pressurizer vessel, reducing the weight of the steam pressurizer by changing its shape from cylindrical to spherical, increasing the rate of pressure growth in the primary circuit. (E.S.)

  18. Suitability of Co as an alloy material for components of the primary circuit of HTR reactors

    International Nuclear Information System (INIS)

    Iniotakis, N.

    1977-02-01

    For high temperature reactors it is of interest if Co-alloys could be used for the different components of the primary cooling circuit. It has been investigated in detail to what amount the Co-60 created by neutron activation of Co-59 contained in the material of the components could possibly contribute to the contamination of the primary cooling circuit of the reactor. The result of these investigations is compared with the contamination of the cooling circuit by fission and activation products like Co-137, Cs-134, Ag-11om etc. For pebble bed reactors with an OTTO-type fuel management it could be shown that there is no limitation for the use of cobalt in alloys for materials of the components in the primary cooling circuit. The only boundary condition is that the local Thermal Flux at the position of the components should be less than phisub(th) 7 n/cm 2 . sec. (orig.) [de

  19. Corrosion product behaviour in the primary circuit of the KNK nuclear reactor facility

    International Nuclear Information System (INIS)

    Stamm, H.H.; Stade, K.Ch.

    1976-01-01

    During nuclear operation of the KNK facility from 1972 until September 1974 the composition and behaviour of radionuclides occuring in the primary circuit were investigated. Besides traces of 140 Ba/ 140 La, no fission product activity was detectable in the KNK primary circuit. The fuel element purification from sodium deposits (prior to transport to the reprocessing plant) did not yield any indication of a fuel element failure during KNK-I operation. The activity inventory of the primary loop was exclusively made up of activated corrosion products and 22 Na. The main activity was due to 65 Zn, followed by 54 Mn, 22 Na, sup(110m)Ag, 182 Ta, 60 Co and 124 Sb. It was found that the sorption of 65 Zn and 54 Mn on crucibles made from nickel was condiserably higher than on vessels made from other materials. This observation was confirmed both in tests with material samples from the primary circuit and for disks of gate valves of the primary circuit. sup(110m)Ag did hardly exhibit any sorption effects and had been dissolved largely homogeneously in the hot primary coolant. In the first primary cold trap which was removed from the circuit after some 20,000 hours of operation, only 65 Zn and 54 Mn were detected in addition to traces of 60 Co and 182 Ta. (author)

  20. Distribution of nutrients, chlorophyll and phytoplankton primary ...

    African Journals Online (AJOL)

    Distribution of nutrients, chlorophyll and phytoplankton primary production in ... Two cruises were undertaken in the vicinity of the Cape Frio upwelling cell ... and concentrations of nitrate, phosphate, silicate, oxygen and chlorophyll a. ... Estimates of the annual primary production for each of the water bodies were calculated.

  1. Analysis of Statistical Distributions Used for Modeling Reliability and Failure Rate of Temperature Alarm Circuit

    International Nuclear Information System (INIS)

    EI-Shanshoury, G.I.

    2011-01-01

    Several statistical distributions are used to model various reliability and maintainability parameters. The applied distribution depends on the' nature of the data being analyzed. The presented paper deals with analysis of some statistical distributions used in reliability to reach the best fit of distribution analysis. The calculations rely on circuit quantity parameters obtained by using Relex 2009 computer program. The statistical analysis of ten different distributions indicated that Weibull distribution gives the best fit distribution for modeling the reliability of the data set of Temperature Alarm Circuit (TAC). However, the Exponential distribution is found to be the best fit distribution for modeling the failure rate

  2. Experiences of activity measurements of primary circuit materials in a WWR-SM research reactor

    International Nuclear Information System (INIS)

    Elek, A.; Toth, M.; Bakos, L.; Vizdos, G.

    1980-01-01

    The activity of water and gas samples taken from the primary circuit have been measured nondestructively for more than two years to monitor the technological parameters of the reactor. In the primary water samples 17 fission products and seven activated traces, as well as six radioactive conponents in the gas samples were determined routinely by Ge/Li gamma-spectrometry. (author)

  3. Effect of a Diagram on Primary Students' Understanding About Electric Circuits

    Science.gov (United States)

    Preston, Christine Margaret

    2017-09-01

    This article reports on the effect of using a diagram to develop primary students' conceptual understanding about electric circuits. Diagrammatic representations of electric circuits are used for teaching and assessment despite the absence of research on their pedagogical effectiveness with young learners. Individual interviews were used to closely analyse Years 3 and 5 (8-11-year-old) students' explanations about electric circuits. Data was collected from 20 students in the same school providing pre-, post- and delayed post-test dialogue. Students' thinking about electric circuits and changes in their explanations provide insights into the role of diagrams in understanding science concepts. Findings indicate that diagram interaction positively enhanced understanding, challenged non-scientific views and promoted scientific models of electric circuits. Differences in students' understanding about electric circuits were influenced by prior knowledge, meta-conceptual awareness and diagram conventions including a stylistic feature of the diagram used. A significant finding that students' conceptual models of electric circuits were energy rather than current based has implications for electricity instruction at the primary level.

  4. 46 CFR 169.682 - Distribution and circuit loads.

    Science.gov (United States)

    2010-10-01

    ... the rating of the overcurrent protective device, computed using the greater of— (1) The lamp sizes to be installed; or (2) 50 watts per outlet. (b) Circuits supplying electrical discharge lamps must be...

  5. Po-210 distribution in uranium-mill circuits

    International Nuclear Information System (INIS)

    McKlveen, J.W.; Hubele, N.D.; McDowell, W.J.; Case, G.N.

    1983-01-01

    Greater than 99% of all incoming Po-210 reports to the tailing piles for both the acid and the alkaline leach uranium circuits. Leached Po-210 may be carried along on small particles rather than dissolved in solution. There does not appear to be any radiologically significant buildup or accumulation in the acid leach circuit, but there are noteworthy amounts in the molybdenum recovery solution

  6. Decontamination between dismantling of the Rapsodie primary coolant circuit

    International Nuclear Information System (INIS)

    Costes, J.R.; Gauchon, J.P.; Antoine, P.

    1991-01-01

    The large-scale decontamination of FBR sodium loops is a novel task, as only a limited number of laboratory-scale results are available to date. The principal objective of this work is to develop a suitable decontamination procedure for application to the primary loops of the RAPSODIE fast breeder reactor as part of decommissionning to Stage 2

  7. Modeling the electrochemistry of the primary circuits of light water reactors

    International Nuclear Information System (INIS)

    Bertuch, A.; Macdonald, D.D.; Pang, J.; Kriksunov, L.; Arioka, K.

    1994-01-01

    To model the corrosion behaviors of the heat transport circuits of light water reactors, a mixed potential model (NTM) has been developed and applied to both boiling water reactors (BWRs) and pressurized water reactors (PWRs). Using the data generated by the GE/UKEA-Harwell radiolysis model, electrochemical potentials (ECPs) have been calculated for the heat transport circuits of eight BWRs operating under hydrogen water chemistry (HWC). By modeling the corrosion behaviors of these reactors, the effectiveness of HWC at limiting IGSCC and IASCC can be determined. For simulating PWR primary circuits, a chemical-radiolysis model (developed by the authors) was used to generate input parameters for the MPM. Corrosion potentials of Type 304 and 316 SSs in PWR primary environments were calculated using the NTM and were found to be in good agreement with the corrosion potentials measured in the laboratory for simulated PWR primary environments

  8. Study of colloidal particles behaviour in the PWR primary circuit conditions

    International Nuclear Information System (INIS)

    Barale, M.

    2006-12-01

    EDF wants to understand, model and limit primary circuit contamination of Pressurized Water Reactors by colloidal particles resulting from corrosion. The electrostatic behaviour of representative oxide particles (cobalt ferrite, nickel ferrite and magnetite) has been studied in primary circuit conditions with the influence of boric acid and lithium hydroxide. The isoelectric point (IEP) and the point of zero charge (PZC) of particles, measured between 5 C and 320 C, exhibit a minimum towards 200 C. The thermodynamic constants of the protonation equilibrium of surface sites were calculated. When boric acid is added, zeta potential and IEP decrease because of borate ions sorption. On the contrary, there is not effect of lithium ions. The modelling of these results under conditions representative of primary circuit shows that these oxides exhibit a negative surface charge, explaining their sorption and adhesion behaviour. (author)

  9. Design on Hygrometry System of Primary Coolant Circuit of HTR-PM

    International Nuclear Information System (INIS)

    Sun Yanfei; Zhong Shuoping; Huang Xiaojin

    2014-01-01

    Helium is the primary coolant in HTR-PM. If vapor get into the helium in primary coolant circuit because of some special reasons, such as the broken of steam-generator tube, chemical reaction will take effect between the graphite in reactor core and vapor in primary coolant circuit, and the safety of the reactor operation will be influenced. So the humidity of the helium in primary coolant circuit is one key parameter of HTR-PM to be monitored in-line. Once the humidity is too high, trigger signal of turning off the reactor must be issued. The hygrometry system of HTR-PM is consisting of filter, cooler, hygrometry sensor, flow meter, and some valves and tube. Helium with temperature of 250℃ is lead into the hygrometry system from the outlet of the main helium blower. After measuring, the helium is re-injected back to the primary circuit. No helium loses in this processing, and no other pump is needed. Key factors and calculations in design on hygrometry system of HTR-PM are described. A sample instrument has been made. Results of experiments proves that this hygrometry system is suitable for monitoring the humidity of the primary coolant of HTR-PM. (author)

  10. Optimization of a primary circuit of the nuclear power plant from the vibration point of view

    International Nuclear Information System (INIS)

    Dupal, J.; Zeman, V.

    2003-01-01

    The primary circuit of the nuclear power plant (NPP) as a dynamical vibrating system can be disturbed by various excitation including earthquake or pressure pulsation generated by main circulation pumps (MCP). Especially, unpleasant pulsation vibration growth can be caused by the small differences of revolutions between main circulation pumps of the individual coolant loops. This growth corresponds to the well known beats. The paper deals with an approach to the improving and optimization of dynamical properties of the whole primary circuit system including the reactor and coolant loops under pressure pulsation. (author)

  11. Specialists meeting on properties of primary circuit structural materials including environmental effects

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1977-07-01

    The Specialists Meeting on Properties of Primary Circuit Structural Materials of LMFBRs covered the following topics: overview of materials program in different countries; mechanical properties of materials in air; fracture mechanics studies - component related activities; impact of environmental influences on mechanical properties; relationship of material properties and design methods. The purpose of the meeting was to provide a forum for exchange of information on structural materials behaviour in primary circuit of fast breeder reactors. Special emphasis was placed on environmental effects such as influence of sodium and irradiation on mechanical properties of reactor materials.

  12. Specialists meeting on properties of primary circuit structural materials including environmental effects

    International Nuclear Information System (INIS)

    1977-01-01

    The Specialists Meeting on Properties of Primary Circuit Structural Materials of LMFBRs covered the following topics: overview of materials program in different countries; mechanical properties of materials in air; fracture mechanics studies - component related activities; impact of environmental influences on mechanical properties; relationship of material properties and design methods. The purpose of the meeting was to provide a forum for exchange of information on structural materials behaviour in primary circuit of fast breeder reactors. Special emphasis was placed on environmental effects such as influence of sodium and irradiation on mechanical properties of reactor materials

  13. The propagation of pressure pulsations in the primary circuit of power plant A1

    International Nuclear Information System (INIS)

    Pecinka, L.

    1976-01-01

    A classification is made of the exciting forces of pressure pulsations in the primary coolant circuit with forced coolant circulation. A mathematical model is constructed of the propagation of pressure pulsations in the system and examples of measurements are given. The measurement methods used and the methods for the generalization of obtained data are assessed. The methods and results of the measurements of hydrodynamic pressure pulsations in a closed primary circuit with forced coolant circulation of the A-1 nuclear power plant are given. (F.M.)

  14. Water quality estimation method for primary coolant circuit

    International Nuclear Information System (INIS)

    Wada, Yoichi; Ibe, Hidefumi.

    1994-01-01

    The present invention is suitable to water quality diagnosis at each of the portions in a reactor upon hydrogen injection for preventing stress corrosion crackings (SCC) of a BWR type reactor. That is, a plurality of simulations are conducted how the water quality at each of the portions in the reactor is changed when hydrogen injection amount is changed depending on the design and operation conditions of the plant. The result of the calculation is stored in a memory device. A water quality distribution in a pressure vessel having a solution which agrees with a value actually measured by a water quality measuring device disposed at the outside of a reactor core is retrieved from the results of the calculation. If no agreeing solution can be found, water quality distribution containing the actually measured value is determined based on the result of the calculation by using interpolation. In the present invention, the result of the calculation obtained by the simulation and the actually measured value at the outside of the reactor core can be utilized, to map the distribution of reactor water ingredients on a screen, which can accurately estimate the water quality at the periphery of the reactor core on real time. As a result, an operational efficiency of a reactor which can control water quality upon hydrogen injection at an optimum condition. (I.S.)

  15. DIADEME: A computer code to assess in operation defective fuel characteristics and primary circuit contamination

    Energy Technology Data Exchange (ETDEWEB)

    Genin, J.B. [DEN/DEC/S3C, CEA Cadarache, 13 - Saint-Paul-lez-Durance (France); Harrer, A. [EdF/SEPTEN, 69 - Villeurbanne (France); Musante, Y. [FRAMATOME-ANP, 69 - Lyon (France)

    2002-07-01

    DIADEME is a computer code developed within the framework of R and D cooperation between the French Atomic Energy Commission (CEA), Electricite de France (EdF) and FRAMATOME-ANP. Its aim is to assess in operation defective fuel characteristics and primary circuit contamination for actinides and long half-life fission products involved in health physics problems as well as in waste and decommissioning studies. DIADEME has been developed and qualified for the EDF nuclear power plants. For many years, both theoretical and experimental studies have been carried out at the CEA on the release of fission products and actinides out of defective fuel rods in operation, their migration and deposition in PWR primary circuits. These studies have allowed defect characteristic diagnosis methods to be developed, based on radiochemical measurements of the primary coolant. These methods are generally used along with gamma spectrometry measurements on primary water sampling. In order to be completely efficient, these methods can also be used in connection with an on-line primary water gamma spectrometry device. This permits to obtain the most comprehensive data on fission product activity evolutions at steady state and during operation transients, and allows the on-line characterization of the defective fuel assemblies. For long half-life fission products and for actinides, DIADEME is also able to assess the activities of soluble and insoluble forms in the primary water and in the chemical and voluminal control system (CVCS) filters and resins, as well as those activities deposited on primary circuit surfaces. (author)

  16. DIADEME: A computer code to assess in operation defective fuel characteristics and primary circuit contamination

    International Nuclear Information System (INIS)

    Genin, J.B.; Harrer, A.; Musante, Y.

    2002-01-01

    DIADEME is a computer code developed within the framework of R and D cooperation between the French Atomic Energy Commission (CEA), Electricite de France (EdF) and FRAMATOME-ANP. Its aim is to assess in operation defective fuel characteristics and primary circuit contamination for actinides and long half-life fission products involved in health physics problems as well as in waste and decommissioning studies. DIADEME has been developed and qualified for the EDF nuclear power plants. For many years, both theoretical and experimental studies have been carried out at the CEA on the release of fission products and actinides out of defective fuel rods in operation, their migration and deposition in PWR primary circuits. These studies have allowed defect characteristic diagnosis methods to be developed, based on radiochemical measurements of the primary coolant. These methods are generally used along with gamma spectrometry measurements on primary water sampling. In order to be completely efficient, these methods can also be used in connection with an on-line primary water gamma spectrometry device. This permits to obtain the most comprehensive data on fission product activity evolutions at steady state and during operation transients, and allows the on-line characterization of the defective fuel assemblies. For long half-life fission products and for actinides, DIADEME is also able to assess the activities of soluble and insoluble forms in the primary water and in the chemical and voluminal control system (CVCS) filters and resins, as well as those activities deposited on primary circuit surfaces. (author)

  17. Modelling the behaviour of corrosion products in the primary heat transfer circuits of pressurised water reactors

    International Nuclear Information System (INIS)

    Rodliffe, R.S.; Polley, M.V.; Thornton, E.W.

    1985-05-01

    The redistribution of corrosion products from the primary circuit surfaces of a water reactor can result in increased flow resistance, poorer heat transfer performance, fuel failure and radioactive contamination of circuit surfaces. The environment is generally sufficiently well controlled to ensure that the first three effects are not limiting. The last effect is of particular importance since radioactive corrosion products are major contributors to shutdown fields and since it is necessary to ensure that the radiation exposure of personnel is as low as reasonably achievable. This review focusses attention on the principles which must form the basis for any mechanistic model describing the formation, transport and deposition of radioactive corrosion products. It is relevant to all water reactors in which the primary heat transfer medium is predominantly single-phase water and in which steam is generated in a secondary circuit, i.e. including CANDU pressurised heavy water reactors, Sovient VVERs, etc. (author)

  18. Modeling in fast dynamics of accidents in the primary circuit of PWR type reactors

    International Nuclear Information System (INIS)

    Robbe, M.F.

    2003-12-01

    Two kinds of accidents, liable to occur in the primary circuit of a Pressurized Water Reactor and involving fast dynamic phenomena, are analyzed. The Loss Of Coolant Accident (LOCA) is the accident used to define the current PWR. It consists in a large-size break located in a pipe of the primary circuit. A blowdown wave propagates through the circuit. The pressure differences between the different zones of the reactor induce high stresses in the structures of the lower head and may degrade the reactor core. The primary circuit starts emptying from the break opening. Pressure decreases very quickly, involving a large steaming. Two thermal-hydraulic simulations of the blowdown phase of a LOCA are computed with the Europlexus code. The primary circuit is represented by a pipe-model including the hydraulic peculiarities of the circuit. The main differences between both computations concern the kind of reactor, the break location and model, and the initialization of the accidental operation. Steam explosion is a hypothetical severe accident liable to happen after a core melting. The molten part of the core (called corium) falls in the lower part of the reactor. The interaction between the hot corium and the cold water remaining at the bottom of the vessel induces a massive and violent vaporization of water, similar to an explosive phenomenon. A shock wave propagates in the vessel. what can damage seriously the neighbouring structures or drill the vessel. This work presents a synthesis of in-vessel parametrical studies carried out with the Europlexus code, the linkage of the thermal-hydraulic code Mc3d dedicated to the pre-mixing phase with the Europlexus code dealing with the explosion, and finally a benchmark between the Cigalon and Europlexus codes relative to the Vulcano mock-up. (author)

  19. Comparison of decay heat exchangers placing in the primary circuit of pool type fast reactor

    International Nuclear Information System (INIS)

    Birbraer, P.N.; Gorbunov, V.S.; Zotov, V.G.; Kuzavkov, N.G.; Pykhonin, V.A.; Sobolev, V.A.; Ryzhov, V.A.

    1993-01-01

    Description of two alternative arrangements of decay beat exchangers (DHXs) in the fast reactor tank is presented: in 'hot' cavity and in 'cold' cavity. The results of calculation for the two alternative arrangements as regards static and dynamic parameters in the primary circuit on 1-D program are given. (author)

  20. Analysis of the NPP-V1 primary circuit fast cooldown

    International Nuclear Information System (INIS)

    Filo, J.; Bazso, Z.; Vranka, L.

    1994-01-01

    Results of thermal-hydraulic calculations of the NPP-V1 primary circuit fast cooldown during small leakage through openings of diameter 20, 32 and 50 mm as well as analyses of cooldown following the steam pipeline break at nominal and null reactor power are given in this paper. 4 refs, 24 figs, 1 tab

  1. Activity build-up in the primary circuit of pressurized water reactors

    International Nuclear Information System (INIS)

    Sachse, G.; Mittag, I.

    1986-01-01

    Based upon international literature, the following topics are reviewed: research and development efforts; release, transport, and deposition of radioactive corrosion products under primary circuit conditions; experimental results in test and technical systems; possibilities of controlling radiation fields in nuclear power plants by water-chemical measures, decontamination, and high-temperature filtration. (author)

  2. Evolution of a Family Nurse Practitioner Program to Improve Primary Care Distribution

    Science.gov (United States)

    Andrus, Len Hughes; Fenley, Mary D.

    1976-01-01

    Describes a Family Nurse Practitioner Program that has effectively improved the distribution of primary health care manpower in rural areas. Program characteristics include selection of personnel from areas of need, decentralization of clinical and didactic training sites, competency-based portable curriculum, and circuit-riding institutionally…

  3. Retrofitting the instrumentation and control system of primary cooling circuit from TRIGA INR 14 MW reactor

    International Nuclear Information System (INIS)

    Preda, M.; Ciocanescu, M.; Ana, E. M.; Cristea, D.

    2008-01-01

    Activities of retrofitting the instrumentation and control system from TRIGA INR primary cooling circuit consists in replacement of actual system for: - parameter measurement; - safety; - reactor external scramming; - protection, command and supply for electrical elements of the system. This retrofitting project is designed to ensure the necessary features of reactor external safety and for technological parameter measurement. The new safety system of main cooling circuit is completely separated from its operating system and is arranged in a panel assembly in reactor control room. The operating system has the following features: - data acquisition; - parameter value and state of command elements displaying; - command elements on hierarchical levels; - operator information through visual and acoustic alarm. (authors)

  4. TRANP - a computer code for digital simulation of steady - state and transient behavior of a pressurizer water reactor primary circuit

    International Nuclear Information System (INIS)

    Chalhoub, E.S.

    1980-09-01

    A digital computer code TRANP was developed to simulate the steady-state and transient behavior of a pressurizer water reactor primary circuit. The development of this code was based on the combining of three codes already developed for the simulation of a PWR core, a pressurizer, a steam generator and a main coolant pump, representing the primary circuit components. (Author) [pt

  5. Cobalt deposition studies in the primary circuit under BWR conditions (Phase 1 and 2)

    International Nuclear Information System (INIS)

    Bennett, Peter

    1996-04-01

    This report presents the results from the first 2 phases of an experiment performed to investigate the effects of water chemistry on cobalt transport and deposition in the primary circuit under BWR conditions. Two high pressure water loops have been used to compare the incorporation of cobalt into the oxide films on coupons of various LWR primary circuit constructional materials, with several pretreatments, under Hydrogen Water Chemistry (HWC) and Normal Water Chemistry (NWC) conditions. Cobalt-60 deposition rates onto samples that had been pre-oxidised in air were lower than on samples that had been exposed previously in a water loop or had untreated surfaces. In NWC, oxide layers were thicker, normalised Co-60 deposition rates were higher and Co-60 activities per unit volume of oxide were greater. Some evidence has been produced to support the conclusions of other workers that a chromium-rich outer oxide layer is responsible for enhanced cobalt incorporation. (author)

  6. Primary circuit contamination in nuclear power plants: contribution to occupational exposure

    International Nuclear Information System (INIS)

    Provens, H.

    2002-01-01

    In every country since the 80's, a clear downward trend is observed concerning the occupational doses at nuclear power plants, as shows the regularly decreasing annual collective dose per operating reactor. Even if technology and work management are improving, the reduction and the control of radiation sources remain one critical point. This paper summarizes the results of an extended study on the primary circuit contamination in nuclear power plants and its contribution to workers' exposure. The paper reviews the origin and mechanisms of radiation production and the different ways of radiation control or reduction based on physical and chemical parameters and not organisational or human factors. It underlines that chemistry control of the primary circuit is one essential component of radiation protection optimisation in nuclear power plants. Results reported come from scientific data in open literature and cannot be generalized to all the power plants

  7. Chemical aspects of fission product transport in the primary circuit of a light water reactor

    International Nuclear Information System (INIS)

    Bowsher, B.R.; Dickinson, S.; Nichols, A.L.; Ogden, J.S.; Potter, P.E.

    1985-01-01

    The transport and fission products in the primary circuit of a light water reactor are of fundamental importance in assessing the consequences of severe accidents. Recent experimental studies have concentrated upon the behaviour of simulant fission product species such as caesium iodide, caesium hydroxide and tellurium, in terms of their vapour deposition characteristics onto metals representative of primary circuit materials. An induction furnace has been used to generate high-density/structural materials aerosols for subsequent analysis, and similar equipment has been incorporated into a glove-box to study lightly-irradiated UO/sub 2/ clad in Zircaloy. Analytical techniques are being developed to assist in the identification of fission product chemical species released from the fuel at temperatures from 1000 to 2500 0 C. Matrix isolation-infrared spectroscopy has been used to identify species in the vapour phase, and specific data using this technique are reported

  8. Chemical aspects of fission product transport in the primary circuit of a light water reactor

    International Nuclear Information System (INIS)

    Bowsher, B.R.; Dickinson, S.; Nichols, A.L.; Ogden, J.S.; Potter, P.E.

    1985-01-01

    The transport and deposition of fission products in the primary circuit of a light water reactor are of fundamental importance in assessing the consequences of severe accidents. Recent experimental studies have concentrated upon the behavior of simulant fission product species such as cesium iodide, cesium hydroxide and tellurium, in terms of their vapor deposition characteristics onto metals representative of primary circuit materials. An induction furnace has been used to generate high density/structural materials aerosols for subsequent analysis, and similar equipment has been incorporated into a glove-box to study lightly-irradiated UO 2 clad in Zircaloy. Analytical techniques are being developed to assist in the identification of fission product chemical species released from the fuel at temperatures from 1000 to 2500 0 C. Matrix isolation-infrared spectroscopy has been used to identify species in the vapor phase, and specific data using this technique are reported

  9. Experience in vibro-acoustic control of primary coolant circuit aggregates

    International Nuclear Information System (INIS)

    Sedov, V.K.; Adamenkov, K.A.

    1977-01-01

    Fundamental principles and possibilities of vibro-acoustic control of the primary coolant circuit in nuclear power plants for detecting failures (slack parts, penetration of foreign bodies, crack formation, etc.) are presented. As a result of pressure and flow rate fluctuations such failures give rise to characteristic changes in apmplitude and frequency of vibration and technological noise from the different aggregates with respect to a 'calibration' spectrum taken in the intact state. Nature and location of the failures may be determined by statistical analysis of the signals recorded from pressure and acceleration gauges. Certain parts of the primary circuit are controlled, especially the main circulation pumps. Additionally, neutron noise has been measured in order to control the core insertions. The method is illustrated by means of measurements performed in the units 1 to 4 of the Novovoronezh nuclear power plant during start-up operation and continuous operation. (author)

  10. Experience in vibro-acoustic control of primary coolant circuit aggregates

    Energy Technology Data Exchange (ETDEWEB)

    Sedov, V K; Adamenkov, K A [Nuclear power plant Novo-Voronesh (USSR)

    1977-10-01

    Fundamental principles and possibilities of vibro-acoustic control of the primary coolant circuit in nuclear power plants for detecting failures (slack parts, penetration of foreign bodies, crack formation, etc.) are presented. As a result of pressure and flow rate fluctuations such failures give rise to characteristic changes in apmplitude and frequency of vibration and technological noise from the different aggregates with respect to a 'calibration' spectrum taken in the intact state. Nature and location of the failures may be determined by statistical analysis of the signals recorded from pressure and acceleration gauges. Certain parts of the primary circuit are controlled, especially the main circulation pumps. Additionally, neutron noise has been measured in order to control the core insertions. The method is illustrated by means of measurements performed in the units 1 to 4 of the Novovoronezh nuclear power plant during start-up operation and continuous operation.

  11. An overview of the U.S. programs on properties of primary circuit materials

    International Nuclear Information System (INIS)

    Brinkman, C.R.; Sikka, V.K.; Booker, M.K.

    1977-01-01

    The objective of U.S. Breeder Reactor Programs associated with primary circuit structural materials is to develop the design data base and associated design technology on existing commercially available materials as well as new alloys. This will permit economic operation of components at acceptable levels of plant availability and at up to 40-yr lifetimes for inaccessible components. Long-term component reliability, elevated-temperature service within the creep range, and resistance to sodium attack and irradiation damage, along with design in compliance with ASME Codes and RDT Specifications, have required that the U.S. Programs be directed toward contributing knowledge in a number of areas. These areas, relating to material deformation, failure modes, compatibility, fabrication, long-term behavior, irradiation damage, and availability will be discussed. The U.S. Structural Material Programs concerned with primary-circuit components will be reviewed, and their current and future contributions to knowledge of these areas will be explained. (author)

  12. Overview of the U.S. programs on properties of primary circuit materials

    International Nuclear Information System (INIS)

    Brinkman, C.R.; Sikka, V.K.; Booker, M.K.

    1977-01-01

    The objective of U.S. Breeder Reactor Programs associated with primary circuit structural materials is to develop the design data base and associated design technology on existing commercially available materials as well as new alloys. This will permit economic operation of components at acceptable levels of plant availability and at up to 40-year lifetimes for inaccessible components. Long-term component reliability, elevated-temperature service within the creep range, and resistance to sodium attack and irradiation damage, along with design in compliance with ASME Codes and RDT Specifications, have required that the U.S. programs be directed toward contributing knowledge in a number of areas. These areas, relating to material deformation, failure modes, compatibility, fabrication, long-term behavior, irradiation damage, and availability will be discussed. The U.S. Structural Material Programs concerned with primary-circuit components will be reviewed, and their current and future contributions to knowledge of these areas will be explained

  13. Evaluation of specific activity in the primary circuit of SMART-P

    International Nuclear Information System (INIS)

    Kim, Ah Young; Choi, Byung Seon; Kim, Seong Hoon; Yoon, Ju Hyeon; Zee, Sung Qunn

    2005-01-01

    SMART-P is a soluble boron free reactor, and the ammonia is used as a pH reagent. The titanium alloy, which has a high corrosion resistance, is chosen as a steam generator tube material. Despite these design features to achieve the corrosion reduction, it is expected that SMART-P exhibits a relatively high specific activity in the coolant due to the lack of purification during the power operation. The main reason for the high specific activity is the activation and transportation of the corrosion products that released from the primary circuit surfaces. The objective of this work is to analyze the corrosion product activity in the primary circuit of SMART-P using a multi-region model, KORA. This model, which is incorporated with the mass and activity transport between the dissolved corrosion products in the coolant and the surface, describes the specific activity of corrosion products in coolant and on the surfaces according to the operation modes

  14. An overview of the U.S. programs on properties of primary circuit materials

    Energy Technology Data Exchange (ETDEWEB)

    Brinkman, C R; Sikka, V K; Booker, M K [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    1977-07-01

    The objective of U.S. Breeder Reactor Programs associated with primary circuit structural materials is to develop the design data base and associated design technology on existing commercially available materials as well as new alloys. This will permit economic operation of components at acceptable levels of plant availability and at up to 40-yr lifetimes for inaccessible components. Long-term component reliability, elevated-temperature service within the creep range, and resistance to sodium attack and irradiation damage, along with design in compliance with ASME Codes and RDT Specifications, have required that the U.S. Programs be directed toward contributing knowledge in a number of areas. These areas, relating to material deformation, failure modes, compatibility, fabrication, long-term behavior, irradiation damage, and availability will be discussed. The U.S. Structural Material Programs concerned with primary-circuit components will be reviewed, and their current and future contributions to knowledge of these areas will be explained. (author)

  15. Insights into iodine behaviour and speciation in the Phébus primary circuit

    International Nuclear Information System (INIS)

    Girault, N.; Payot, F.

    2013-01-01

    Highlights: • Unexpectedly, gaseous iodine was transported in the circuit during some test periods. • The highest gaseous iodine fraction was measured in FPT3. • Several iodine vapours were evidenced in the hot leg, CsI being not predominant. • Equilibrium gas-phase chemistry do not explain the experimental iodine results. • Kinetic limitations in iodine reactions probably played a significant role. - Abstract: The Phébus FP integral test series studies a large spectrum of the phenomenology of severe accidents in water-cooled nuclear reactors. These tests represent a unique source of representative integral source term data, covering fuel rod degradation and behaviour of fission-products released via the coolant system into the containment. The present analysis concerns the behaviour of iodine in the test circuit representing the Reactor Coolant System (RCS) which reaches gas temperatures of nearly 1600 °C at the circuit entrance and descending to 150 °C before entry into the containment. The stake in the data analysis is a better understanding of iodine phenomenology in RCS. This is indeed all the more serious as iodine is one of the most radiological important fission products released from the fuel and may exist under highly volatile forms even within cold leg thermal– hydraulics conditions. Complex and coupled phenomena arise in the primary circuit during the tests as the temperature decreases (drops) from the inlet of the circuit to the outlet. These are respectively for the iodine vapours and aerosols: chemical transformation, condensation on walls/aerosols, homogeneous nucleation into aerosols and agglomeration, deposition by thermophoresis. Depending on the location in the primary circuit, a combination of these phenomena occurred simultaneously. The phenomenological behaviour of iodine in RCS will be appraised through the analyses of the iodine transport, retention, vapour speciation and gaseous occurrence in the Phébus FP primary circuit

  16. Heat and fluid dynamic in the primary circuit of a research reactor

    International Nuclear Information System (INIS)

    Gebrin, A.N.

    1986-01-01

    Aiming at the analysis of some thermohydraulic transients that may affect the safety of a reactor core, a FORTRAN program was developed which evaluates the heat and fluid dynamics in the primary circuit of a research reactor. The selection of the pump, the determination of the length and diameter of the pipes, as well as the appropriate arrangement of the pipes and heat exchanger, are determined from the stationary regime. (Author) [pt

  17. Hard alloys testing-machine for values of PWR primary coolant circuits

    International Nuclear Information System (INIS)

    Campan, J.L.; Sauze, A.

    1980-01-01

    Testing of valve parts or material used in valve fabrication and particularly seizing conditions in friction of plane surfaces coated with hard alloys of the type stellite. The testing equipment called Marguerite is composed of a hot pressurized water loop in conditions similar to PWR primary coolant circuits (320 0 C, 150 bars) and a testing-machine with measuring instruments. Testing conditions and samples are described [fr

  18. Experiments for simulating a great leak in the primary coolant circuit of a PWR type reactor

    International Nuclear Information System (INIS)

    Liebig, E.

    1977-01-01

    A loss of coolant accident is to be simulated on a high pressure test rig. The accident is initiated by an externally induced rupture of a pair of rupture-disks installed in a coolant ejection device. Several problems of simulating leaks in the primary coolant circuit of PWR type reactors are dealt with. The selection of appropriate rupture-disks for such experiments is described

  19. PWR type reactor equipped with a primary circuit loop water level gauge

    International Nuclear Information System (INIS)

    Suzuki, Mitsuhiro.

    1990-01-01

    The time of lowering a water level to less than the position of high temperature side pipeway nozzle has been rather delayed because of the swelling of mixed water level due to heat generation of the reactor core. Further, there has been a certain restriction for the installation, maintenance and adjustment of a water level gauge since it is at a position under high radiation exposure. Then, a differential pressure type water level gauge with temperature compensation is disposed at a portion below a water level gauge of a pressurizer and between the steam generator exit plenum and the lower end of the loop seal. Further, a similar water level system is disposed to all of the loops of the primary circulation circuits. In a case that the amount of water contained in a reactor container should decreased upon occurrence of loss of coolant accidents caused by small rupture and stoppage of primary circuit pumps, lowering of the water level preceding to the lowering of the water level in the reactor core is detected to ensure the amount of water. Since they are disposed to all of the loops and ensure the excess margin, reliability for the detection of the amount of contained water can be improved by averaging time for the data of the water level and averaging the entire systems, even when there are vibrations in the fluid or pressure in the primary circuit. (N.H.)

  20. Radioactive 55Fe contamination in the primary circuit of WWER-440

    International Nuclear Information System (INIS)

    Ruskov, T.; Ruskov, R.; Dobrevski, I.; Konnova, S.; Zaharieva, N.; Menut, P.

    2001-01-01

    The isotope 55 Fe generation in the steel construction materials of the reactor and the mechanism of internal irradiation and blood affection by the 55 Fe are briefly discussed in this paper. The paper also presents the results from calculation of direct generation of 55 Fe due to neutron irradiation of different iron-contained parts of the reactor system such as the steel shell of the reactor core, the core basket, the steel shaft of the reactor vessels. Calculations are performed with specially developed program code DIRGEN. Another type of contamination, considered in the paper is due to the corrosion of materials and erosion-dissolution processes in the primary circuit of WWER with their subsequent deposition-precipitation on the inner surface of the primary circuit. The real time calculations of the 55 Fe activity are performed, by using of the updated computer code MIGA-RT. The obtained results show that the 55 Fe activity deposition on the inner surfaces of the primary circuits reaches the values of 103 kBq/cm 2 for the reactor core surfaces and 102 kBq/cm 2 for the out-of-core surfaces. The activity values are in one order of magnitude higher than the corresponding activity values due to 60 Co buildup

  1. Contamination of a PWR primary circuit by fuel pins with failed cladding

    International Nuclear Information System (INIS)

    Janvier, J.C.; Chagrot, M.

    1979-01-01

    The safety authorities in the principal nuclear countries appear to be attaching increasing importance to keeping reactor primary circuits as contamination-free as possible. Therefore, the consequences of cladding failures and especially of those resulting from fabrication defects have to be evaluated, for when these failures become systematic in nature they constitute an important source of contamination in pressurized-water reactors. The Grenoble Nuclear Research Centre is implementing a programme on the study of such failures with a view to analysing the behaviour of failed fuel elements. A distinction is made between two types of cladding failure, depending on whether the primary water enters the fuel pin as soon as the circuits are pressurized (fabrication defect) or whether the failure is caused during operation. The emission of gaseous fission products and halogens has been analysed in different operating modes (steady-state or transient), and in spite of the complexity of the phenomena involved, some results have been obtained which already enable one to evaluate fission product contamination of the primary circuit. (author)

  2. A procedure for temperature-stress fields calculation of WWER-1000 primary circuit in PTS event

    Energy Technology Data Exchange (ETDEWEB)

    Petkov, G [Technical Univ., Dept. Thermal and Nuclear Power Engineering, Sofia (Bulgaria); Groudev, P; Argirov, J [Bulgarian Academy of Science, Inst. for Nuclear Research and Nuclear Energy, Sofia (Bulgaria)

    1997-09-01

    The paper presents the procedure of an investigation of WWER-1000 primary circuit temperature-stress field by the use of thermohydraulic computation data for a pressurized thermal shock event ``Core overcooling``. The procedure is based on a model of the plane stress state with ideal contact between wall and medium for the calculation. The computation data are calculated on the base of WWER-1000 thermohydraulic model by the RELAP5/MOD3 codes. This model was developed jointly by the Bulgarian and BNL/USA staff to provide an analytical tool for performing safety analysis. As a result of calculations by codes the computation data for temperature field law (linear laws of a few distinguished parts) and pressure of coolant at points on inner surface of WWER-1000 primary circuit equipment are received. Such calculations can be used as a base for determination of all-important load-carrying sections of the primary circuit pipes and vessels, which need further consideration. (author). 7 refs, 2 figs, 2 tabs.

  3. Components of the LWR primary circuit. Pt. 2. Komponenten des Primaerkreises von Leichtwasserreaktoren. T. 2

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    This standard is to be applied to components made of metallic materials, operated at design temperatures of up to 673 K (400/sup 0/C). The primary circuit as the pressure containment of the reactor coolant comprises: Reactor pressure vessel (without internals), steam generator (primary loop), pressurizer, reactor coolant pump housing, interconnecting pipings between the components mentioned above and appropriate various valve and instrument casings, pipings branding from the above components and interconnecting pipings, including the appropriate instrument casings, up to and including the first isolating valve, pressure shielding of control rod drives.

  4. High temperature alloys for the primary circuit of a prototype nuclear process heat plant

    International Nuclear Information System (INIS)

    Ennis, P.J.; Schuster, H.

    1979-01-01

    As part of a comprehensive materials test programme for the High Temperature Reactor Project 'Prototype Plant for Nuclear Process Heat' (PNP), high temperature alloys are being investigated for primary circuit components operating at temperatures above 750 0 C. On the basis of important material parameters, in particular corrosion behaviour and mechanical properties in primary coolant helium, the potential of candidate alloys is discussed. By comparing specific PNP materials data with the requirements of PNP and those of conventional plant, the implications for the materials programme and component design are given. (orig.)

  5. Components of the LWR primary circuit. Pt. 2. Design, construction and calculation. Draft

    International Nuclear Information System (INIS)

    1995-01-01

    This standard is to be applied to components made of metallic materials, operated at design temperatures of up to 673 K (400 deg C). The primary circuit as the pressure containment of the reactor coolant comprises: Reactor pressure vessel (without internals), steam generator (primary loop), pressurizer, reactor coolant pump housing, interconnecting pipings between the components mentioned above and appropriate various valve and instrument casings, pipings branding from the above components and interconnecting pipings, including the appropriate instrument casings, up to and including the first isolating valve, pressure shielding of control rod drives. (orig.) [de

  6. Influence of hydrazine primary water chemistry on corrosion of fuel cladding and primary circuit components

    International Nuclear Information System (INIS)

    Iourmanov, V.; Pashevich, V.; Bogancs, J.; Tilky, P.; Schunk, J.; Pinter, T.

    1999-01-01

    Earlier at Paks 1-4 NPP standard ammonia chemistry was in use. The following station performance indicators were improved when hydrazine primary water chemistry was introduced: occupational radiation exposures of personnel; gamma-radiation dose rates near primary system components during refuelling and maintenance outages. The reduction of radiation exposures and radiation fields were achieved without significant expenses. Recent results of experimental studies allowed to explain the mechanism of hydrazine dosing influence on: corrosion rate of structure materials in primary coolant; behaviour of soluble and insoluble corrosion products including long-life corrosion-induced radionuclides in primary system during steady-state and transient operation modes; radiolytic generation of oxidising radiolytic products in core and its corrosion activity in primary system; radiation situation during refuelling and maintenance outages; foreign material degradation and removal (including corrosion active oxidant species) from primary system during abnormal events. Operational experience and experimental data have shown that hydrazine primary water chemistry allows to reduce corrosion wear and thereby makes it possible to extend the life-time of plant components in primary system. (author)

  7. Beyond the temporal pole: limbic memory circuit in the semantic variant of primary progressive aphasia.

    Science.gov (United States)

    Tan, Rachel H; Wong, Stephanie; Kril, Jillian J; Piguet, Olivier; Hornberger, Michael; Hodges, John R; Halliday, Glenda M

    2014-07-01

    Despite accruing evidence for relative preservation of episodic memory in the semantic variant of primary progressive aphasia (previously semantic dementia), the neural basis for this remains unclear, particularly in light of their well-established hippocampal involvement. We recently investigated the Papez network of memory structures across pathological subtypes of behavioural variant frontotemporal dementia and demonstrated severe degeneration of all relay nodes, with the anterior thalamus in particular emerging as crucial for intact episodic memory. The present study investigated the status of key components of Papez circuit (hippocampus, mammillary bodies, anterior thalamus, cingulate cortex) and anterior temporal cortex using volumetric and quantitative cell counting methods in pathologically-confirmed cases with semantic variant of primary progressive aphasia (n = 8; 61-83 years; three males), behavioural variant frontotemporal dementia with TDP pathology (n = 9; 53-82 years; six males) and healthy controls (n = 8, 50-86 years; four males). Behavioural variant frontotemporal dementia cases with TDP pathology were selected because of the association between the semantic variant of primary progressive aphasia and TDP pathology. Our findings revealed that the semantic variant of primary progressive aphasia and behavioural variant frontotemporal dementia show similar degrees of anterior thalamic atrophy. The mammillary bodies and hippocampal body and tail were preserved in the semantic variant of primary progressive aphasia but were significantly atrophic in behavioural variant frontotemporal dementia. Importantly, atrophy in the anterior thalamus and mild progressive atrophy in the body of the hippocampus emerged as the main memory circuit regions correlated with increasing dementia severity in the semantic variant of primary progressive aphasia. Quantitation of neuronal populations in the cingulate cortices confirmed the selective loss of anterior cingulate

  8. High temperature filtration of radioactivable corrosion products in the primary circuit of PWR type reactors

    International Nuclear Information System (INIS)

    Dolle, L.

    1976-01-01

    A effective limitation to the deposition of radioactive corrosion products in the core of a reactor at power operation, is to be obtained by filtering the water of the primary circuit at a flow rate upper than 1% of the coolant flow rate. However, in view of accounting for more important release of corrosion products during the reactor start-up and also for some possible variations in the efficiency of the system, it is better that the flow rate to be treated by the cleaning circuit is stated at 5%. Filtration must be effected at the temperature of the primary circuit and preferably on each loop. To this end, the feasibility of electromagnetic filtration or filtration through a deep bed of granulated graphite has been studied. The on-loop tests effected on each filter gave efficiencies and yields respectively upper than 90% and 99% for magnetite and ferrite particles in suspension in water at 250 deg C. Such results confirm the interest lying in high temperature filtration and lead to envisage its application to reactors [fr

  9. High-dimensional quantum key distribution based on multicore fiber using silicon photonic integrated circuits

    DEFF Research Database (Denmark)

    Ding, Yunhong; Bacco, Davide; Dalgaard, Kjeld

    2017-01-01

    is intrinsically limited to 1 bit/photon. Here we propose and experimentally demonstrate, for the first time, a high-dimensional quantum key distribution protocol based on space division multiplexing in multicore fiber using silicon photonic integrated lightwave circuits. We successfully realized three mutually......-dimensional quantum states, and enables breaking the information efficiency limit of traditional quantum key distribution protocols. In addition, the silicon photonic circuits used in our work integrate variable optical attenuators, highly efficient multicore fiber couplers, and Mach-Zehnder interferometers, enabling...

  10. Calculated model of radioactive fission and corrosion product accumulation and distribution in a fast reactor sodium coolant circuit

    International Nuclear Information System (INIS)

    Kizin, V.D.; Konyashov, V.V.

    1987-01-01

    A simple calculation procedure of radioactive products accumulation and distribution in a primary circuit has been developed on the basis of experimental investigations at the BOR-60 reactor. Common knowledge on the impurity products transfer at the liquid-solid and liquid-gas phase boundary is taken. Use is made of the typical in reactor physics relationships for the description of the products transition to the equipment surfaces, of fission products release, metal corrosion and others. Satisfactory agreement of the calculation data with the experimental ones has been obtained. (orig.)

  11. Process and system for stirring liquid sodium flowing through the primary circuit of a steam generator

    International Nuclear Information System (INIS)

    Fabregue, J.P.

    1982-01-01

    The invention concerns the stirring of the liquid sodium of a steam generator comprising a primary circuit composed of an elongated vessel through which the liquid sodium flows, a secondary circuit composed of a number of tubes extending inside the long cyclindrical vessel. The process consists in imparting simultaneously to the liquid sodium, during its passage through the cylindrical vessel, a movement of continuous rotation about the longitudinal axis of the cylindrical vessel and an alternating series of radial movements, centripetal and centrifugal, in relation to the longitudinal axis, so that each unit quantity of the sodium comes into contact with a large number of tubes. The application particularly concerns steam generators for nuclear power stations [fr

  12. Method for heating of the primary circuit of WWER electric power units at cold start-up

    International Nuclear Information System (INIS)

    Ivanov, I.N.; Dimitrov, B.D.; Korkinova, M.I.

    1982-01-01

    The method increases the heating rate and shorten the start-up time of the electric power units. It comprises a primary stopping of the reactor core heating and provides a forced circulation of the heat-carrier through the circulation cycles of the primary circuit. The thermal energy is supplied in one or several steam generators in the secondary circuit of an NPP operating unit. 1 cl., 3 figs

  13. The impact of radiolytic yield on the calculated ECP in PWR primary coolant circuits

    International Nuclear Information System (INIS)

    Urquidi-Macdonald, Mirna; Pitt, Jonathan; Macdonald, Digby D.

    2007-01-01

    A code, PWR-ECP, comprising chemistry, radiolysis, and mixed potential models has been developed to calculate radiolytic species concentrations and the corrosion potential of structural components at closely spaced points around the primary coolant circuits of pressurized water reactors (PWRs). The pH(T) of the coolant is calculated at each point of the primary-loop using a chemistry model for the B(OH) 3 + LiOH system. Although the chemistry/radiolysis/mixed potential code has the ability to calculate the transient reactor response, only the reactor steady state condition (normal operation) is discussed in this paper. The radiolysis model is a modified version of the code previously developed by Macdonald and coworkers to model the radiochemistry and corrosion properties of boiling water reactor primary coolant circuits. In the present work, the PWR-ECP code is used to explore the sensitivity of the calculated electrochemical corrosion potential (ECP) to the set of radiolytic yield data adopted; in this case, one set had been developed from ambient temperature experiments and another set reported elevated temperatures data. The calculations show that the calculated ECP is sensitive to the adopted values for the radiolytic yields

  14. Explaining the absence of Co-58 radiation fields around CANDU reactor primary circuit

    International Nuclear Information System (INIS)

    Burrill, K.A.; Guzonas, D.A.

    2002-01-01

    Radiation fields from Co-58 are rarely detected in CANDU plants. For example, Ge(Li) surveys of the Inconel 600 steam generators at some CANDU plants may show radiation attributed to Co-58 only early in plant life, and most artefacts removed from the primary circuit later in plant operation show no Co-58 present. However, Pressurized Water Reactor plants experience relatively large fields from Co-58 on their isothermal piping, e.g., steam generator channel head, and steam generators tube sampling programs do show deposits in the tubes with significant Co-58 compared to other radionuclides such as Co-60. CANDU reactors have high concentrations of dissolved iron due to the extensive use of carbon steel for the isothermal piping, e.g., feeders, headers, and steam generator channel heads. A dissolved iron transport diagram that was proposed recently for the primary circuit of CANDU plants has been validated by comparison of predicted deposit weights with plant deposit data from various components. One feature of the diagram is dissolved iron precipitation inside the steam generators tubes. An hypothesis is advanced here in which precipitating dissolved iron is proposed to occlude dissolved nickel. This removal mechanism may prevent the solubility of dissolved nickel from being exceeded anywhere around the primary circuit. In particular, this mechanism could avoid NiO precipitation in the core and the generation of large quantities of Co-58. Using this mechanism along with the known solubility behaviour of NiO with temperature, a dissolved nickel transport diagram has been proposed for CANDU plants. (authors)

  15. A distributed chemosensory circuit for oxygen preference in C. elegans.

    Directory of Open Access Journals (Sweden)

    Andy J Chang

    2006-09-01

    Full Text Available The nematode Caenorhabditis elegans has complex, naturally variable behavioral responses to environmental oxygen, food, and other animals. C. elegans detects oxygen through soluble guanylate cyclase homologs (sGCs and responds to it differently depending on the activity of the neuropeptide receptor NPR-1: npr-1(lf and naturally isolated npr-1(215F animals avoid high oxygen and aggregate in the presence of food; npr-1(215V animals do not. We show here that hyperoxia avoidance integrates food with npr-1 activity through neuromodulation of a distributed oxygen-sensing network. Hyperoxia avoidance is stimulated by sGC-expressing oxygen-sensing neurons, nociceptive neurons, and ADF sensory neurons. In npr-1(215V animals, the switch from weak aerotaxis on food to strong aerotaxis in its absence requires close regulation of the neurotransmitter serotonin in the ADF neurons; high levels of ADF serotonin promote hyperoxia avoidance. In npr-1(lf animals, food regulation is masked by increased activity of the oxygen-sensing neurons. Hyperoxia avoidance is also regulated by the neuronal TGF-beta homolog DAF-7, a secreted mediator of crowding and stress responses. DAF-7 inhibits serotonin synthesis in ADF, suggesting that ADF serotonin is a convergence point for regulation of hyperoxia avoidance. Coalitions of neurons that promote and repress hyperoxia avoidance generate a subtle and flexible response to environmental oxygen.

  16. Role of electromagnetic filter in limitating radioactivity in the primary circuits of light water reactors

    International Nuclear Information System (INIS)

    Dolle, L.

    1978-01-01

    High temperature electromagnetic filtration of particulate corrosion products can be carried out with discharges up to 5% of the cooling flow rate. It allows efficient extraction of particulate matter which rate constants required for considerable reduction of activable crud deposition in the core. The paper holds a review of the preventing operation in the primary circuit of a PWR, and reports experimental results of efficiency measurments with an electromagnetic filter set in out-of-pile and in-pile pressurized water loops. The notable efficiencies towards radioactive fine grain and colloidal matter justify more extensive reactor scale application experiments. (author)

  17. Role of electromagnetic filter in limitating radioactivity in the primary circuits of light water reactors

    International Nuclear Information System (INIS)

    Dolle, L.

    1978-01-01

    High temperature electromagnetic filtration of particulate corrosion products can be carried out with discharges up to 5% of the cooling flow rate. It allows efficient extraction of particulate matter with rate constants required for considerable reduction of activable crud deposition in the core. The paper holds a review of the preventing operation in the primary circuit of a PWR, and reports experimental results of efficiency measurements with an electromagnetic filter set in out-of-pile and in-pile pressurized water loops. The notable efficiencies towards radioactive fine grain and colloidal matter justify more extensive reactor scale application experiments

  18. Activity transport models for PWR primary circuits; PWR-ydinvoimalaitoksen primaeaeripiirin aktiivisuuskulkeutumismallit

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, V; Rosenberg, R [VTT Chemical Technology, Otaniemi (Finland)

    1995-03-01

    The corrosion products activated in the primary circuit form a major source of occupational radiation dose in the PWR reactors. Transport of corrosion activity is a complex process including chemistry, reactor physics, thermodynamics and hydrodynamics. All the mechanisms involved are not known and there is no comprehensive theory for the process, so experimental test loops and plant data are very important in research efforts. Several activity transport modelling attempts have been made to improve the water chemistry control and to minimise corrosion in PWR`s. In this research report some of these models are reviewed with special emphasis on models designed for Soviet VVER type reactors. (51 refs., 16 figs., 4 tabs.).

  19. Study of the formation and transport of corrosion products in PWR primary circuit simulators

    International Nuclear Information System (INIS)

    Noe, M.; Frejaville, G.; Camp, J.J.

    1983-01-01

    The formation, migration and deposition of corrosion products in PWR primary circuits are studied in out-of-reactor loops. The aim of these studies is to limit the build-up of the radiation fields impinging on out-of-flux walls and to reduce the danger of rapid corrosion of fuel cans, taking into account the tougher conditions imposed on current trends in the operation of such industrial plants. Four simulator loops and their respective possibilities and research methods are described. (author)

  20. Decentralization and Distribution Primary Education Access in Indonesia 2014

    OpenAIRE

    Benita, Novinaz

    2016-01-01

    This paper examines decentralisation and distribution of access to primary school in Indonesia. Data come from Indonesia National Socio Economic Survey 2014, and statistic reports from Ministry of education, Ministry Of Finance, and General Election Commision. Descriptive statistic is used to describe spatial distribution of decentralization in primary education system and distribution of primary education access. The results show there are districts disparities in decentralization of primary...

  1. Silicon photonic transceiver circuit for high-speed polarization-based discrete variable quantum key distribution.

    Science.gov (United States)

    Cai, Hong; Long, Christopher M; DeRose, Christopher T; Boynton, Nicholas; Urayama, Junji; Camacho, Ryan; Pomerene, Andrew; Starbuck, Andrew L; Trotter, Douglas C; Davids, Paul S; Lentine, Anthony L

    2017-05-29

    We demonstrate a silicon photonic transceiver circuit for high-speed discrete variable quantum key distribution that employs a common structure for transmit and receive functions. The device is intended for use in polarization-based quantum cryptographic protocols, such as BB84. Our characterization indicates that the circuit can generate the four BB84 states (TE/TM/45°/135° linear polarizations) with >30 dB polarization extinction ratios and gigabit per second modulation speed, and is capable of decoding any polarization bases differing by 90° with high extinction ratios.

  2. Temperature monitoring and leak detection in sodium circuits of FBR using Raman distributed fiber optic sensor

    International Nuclear Information System (INIS)

    Kasinathan, M.; Murali, N.; Sosamma, S.; Babu Rao, C.; Kumar, Anish; Purnachandra Rao, B.; Jayakumar, T.

    2013-01-01

    This paper discusses the fiber optic temperature sensor based leak detection in the coolant circuits of fast breeder reactor. These sensors measure the temperature based on spontaneous Raman scattering principle and is not influenced by the electromagnetic interference. Various experiments were conducted to evaluate the performance of the fiber optic sensor based leak detection using Raman distributed Temperature Sensor (RDTS). This paper also deals with the details of fiber optic sensor type leak detector layout for the coolant circuit of FBR, performance requirement of leak detection system, description of the test facility, experimental procedure and test results of various experiments conducted. (author)

  3. Q-factor of coolant flow in the primary circuit of NPP with pressurised water reactors

    International Nuclear Information System (INIS)

    Proskuryakov, K.N.; Belikov, S.O.; Novikov, K.S.

    2011-01-01

    Systems of preoperational vibration dynamic monitoring in of WWER are presented. The results of measurements during commission of NPP with WWER are presented. The paper provides the result of the research, that estimation of coolant fluctuations caused by pulse perturbation of pressure in the primary circuit NPP. It is shown that results could be received at known value of a Q - factor of acoustical oscillatory system only. The research demonstrates the results of dependence of the sound speed from the mass steam content in the coolant flow thru reactor core. The worked out results can be used for identification of the reasons of abnormal growth of level of vibrations of fuel assembly, fuel rod, equipment and internals, and for forecasting the operation conditions which provide of vibration - acoustical resonances in the primary loop equipment. (author)

  4. Measurement and evaluation of radioactive corrosion product behaviour in primary sodium circuits of JOYO

    International Nuclear Information System (INIS)

    Ito, K.; Iizawa, K.; Takahashi, K.; Zulquarnain, M.A.; Suzuki, S.; Kinjo, K.

    1992-01-01

    In the experimental fast reactor JOYO, the radioactive corrosion product (CP) measurement has been conducted in the primary sodium circuits during each annual inspection. The measured data has been analyzed by the computer code 'PSYCHE', which has been developed by PNC. Main results obtained from the measurements and/or calculations are as follows; (1) The dominant CP nuclide is 54 Mn followed by 60 Co and 58 Co. (2) Average surface gamma dose rate around the primary piping system at the 8th annual inspection is 0.96 mSv/h. The increasing rate of this value is 0.25 (mSv/h)/EFPY. (3) The calculated deposition densities of 54 Mn and 60 Co agree with measured ones within factor of 0.7 ∼ 1.7. (author)

  5. Study of the contamination level in the primary circuit of a pressurised water reactor

    International Nuclear Information System (INIS)

    Gomit, J.-M.

    1980-07-01

    The purpose of this study is to work out a model which allows to predict the contamination level in the primary circuit of a pressurised water reactor (PWR). We assume that the passage of fission products from fuel (UO 2 ) to water takes place in two stages: a) the fission products created in the fuel diffuse and go out into the gap; b) owing to failure of clad, fission products stored in the gap diffuse into the water. A migration constant will correspond to each of these stages (ν(C) for fuel and ν(J) for gap). We have designed two models: - an empiric model in which constants ν(C) and ν(J) are adjusted from experiments CYRANO and BOUFFON carried out by the CEA; - a theoretical model to describe the physical mechanisms of migration inside the fuel. This leads us to introduce trapping and resolution probabilities. This models lead to a theoretical definition of ν(C). We have undertaken a second qualification of the empiric model using code PROFIP 3. Application to the Tihange reactor enabled us to get a good estimation of activity in the primary circuit and the number of failed rods during the first cycle [fr

  6. An Investigation into Water Chemistry in Primary Coolant Circuit of an Advanced Boiling Water Reactor

    International Nuclear Information System (INIS)

    Wu, Bing-Jhen; Yeh, Tsung-Kuang; Wang, Mei-Ya; Sheu, Rong-Jiun

    2012-09-01

    To ensure operation safety, an optimization on the coolant chemistry in the primary coolant circuit of a nuclear reactor is essential no matter what type or generation the reactor belongs to. For a better understanding toward the water chemistry in an advanced boiling water reactor (ABWR), such as the one being constructed in the northern part of Taiwan, and for a safer operation of this ABWR, we conducted a proactive, thorough water chemistry analysis prior to the completion of this reactor in this study. A numerical simulation model for water chemistry analyses in ABWRs has been developed, based upon the core technology we established in the past. This core technology for water chemistry modeling is basically an integration of water radiolysis, thermal-hydraulics, and reactor physics. The model, by the name of DEMACE - ABWR, is an improved version of the original DEMACE model and was used for radiolysis and water chemistry prediction in the Longmen ABWR in Taiwan. Predicted results pertinent to the water chemistry variation and the corrosion behavior of structure materials in the primary coolant circuit of this ABWR under rated-power operation were reported in this paper. (authors)

  7. Development of a computer code for dynamic analysis of the primary circuit of advanced reactors

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Jussie Soares da; Lira, Carlos A.B.O.; Magalhaes, Mardson A. de Sa, E-mail: cabol@ufpe.b [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2011-07-01

    Currently, advanced reactors are being developed, seeking for enhanced safety, better performance and low environmental impacts. Reactor designs must follow several steps and numerous tests before a conceptual project could be certified. In this sense, computational tools become indispensable in the preparation of such projects. Thus, this study aimed at the development of a computational tool for thermal-hydraulic analysis by coupling two computer codes to evaluate the influence of transients caused by pressure variations and flow surges in the region of the primary circuit of IRIS reactor between the core and the pressurizer. For the simulation, it was used a situation of 'insurge', characterized by the entry of water in the pressurizer, due to the expansion of the refrigerant in the primary circuit. This expansion was represented by a pressure disturbance in step form, through the block 'step' of SIMULINK, thus enabling the transient startup. The results showed that the dynamic tool, obtained through the coupling of the codes, generated very satisfactory responses within model limitations, preserving the most important phenomena in the process. (author)

  8. Pulverulent deposits on fuel assemblies in primary circuit on 2 units at EDF (France)

    International Nuclear Information System (INIS)

    Zatla, A.; Piana, O.

    2015-01-01

    In march 2013, during the moving of some fuel assemblies in the fuel deactivation pool of two units nuclear power plants (Blayais 4 and Chinon B2 units), some fine and powdery deposits in suspension have been observed. In the two cases, the fuel has stayed in the deactivation pool during a long time (12 and 3 months), the units have started for the first time to inject Zinc in the primary circuit in the beginning of the precedent fuel cycle, and the units have operated an extended fuel cycle. EDF has performed analysis to evaluate the harmfulness of the particles and to investigate the mechanisms involved in this phenomenon. 3 conclusions can be drawn. First, the deposits are made up of usual corrosion products issued from the primary circuit components. Secondly, the chemical composition and the powdery characteristics of the deposits exclude nuclear safety risks. Thirdly, the atypical behaviour of the deposits could probably be linked with a modification of their structure due to a zinc effect. Because of the lack of new understanding elements, the extension of zinc injection to other NPP units has been broken off currently in France. EDF is studying the international experience feedback to identify the operating parameters of the nuclear power plant which might influent the phenomenon, and to evaluate if the deposits could enhance fuel cladding corrosion

  9. Fact and fiction in ECP measurement and control in boiling water reactor primary coolant circuits

    International Nuclear Information System (INIS)

    Macdonald, D.D.

    2005-01-01

    A review is presented of various electrochemical potentials, including the electrochemical corrosion potential (ECP), that are used in the mitigation of stress corrosion cracking in the primary coolant circuits of boiling water reactors (BWRs). Attention is paid to carefully defining each potential in terms of fundamental electrochemical concepts, so as to counter the confusion that has arisen due to the misuse of previously accepted terminology. A brief discussion is also included of reference electrodes and it is shown on the basis of experimental data that the use of a platinum redox sensor as a reference electrode in the monitoring of ECP in BWR primary coolant circuits is inappropriate and should be discouraged. If platinum is used as a reference electrode, because of extenuating circumstances (e.g., potential measurements in high dose regions in a reactor core), the onus must be placed on the user to demonstrate quantitatively that the electrode behaves as an equilibrium electrode under the specified conditions and/or that its potential is invariant with changes in the independent variables of the system. Preferably, a means should also be demonstrated of transferring the measured potential to the standard hydrogen electrode (SHE) scale. (orig.)

  10. Development of a computer code for dynamic analysis of the primary circuit of advanced reactors

    International Nuclear Information System (INIS)

    Rocha, Jussie Soares da; Lira, Carlos A.B.O.; Magalhaes, Mardson A. de Sa

    2011-01-01

    Currently, advanced reactors are being developed, seeking for enhanced safety, better performance and low environmental impacts. Reactor designs must follow several steps and numerous tests before a conceptual project could be certified. In this sense, computational tools become indispensable in the preparation of such projects. Thus, this study aimed at the development of a computational tool for thermal-hydraulic analysis by coupling two computer codes to evaluate the influence of transients caused by pressure variations and flow surges in the region of the primary circuit of IRIS reactor between the core and the pressurizer. For the simulation, it was used a situation of 'insurge', characterized by the entry of water in the pressurizer, due to the expansion of the refrigerant in the primary circuit. This expansion was represented by a pressure disturbance in step form, through the block 'step' of SIMULINK, thus enabling the transient startup. The results showed that the dynamic tool, obtained through the coupling of the codes, generated very satisfactory responses within model limitations, preserving the most important phenomena in the process. (author)

  11. Optimal Meter Placement for Distribution Network State Estimation: A Circuit Representation Based MILP Approach

    DEFF Research Database (Denmark)

    Chen, Xiaoshuang; Lin, Jin; Wan, Can

    2016-01-01

    State estimation (SE) in distribution networks is not as accurate as that in transmission networks. Traditionally, distribution networks (DNs) are lack of direct measurements due to the limitations of investments and the difficulties of maintenance. Therefore, it is critical to improve the accuracy...... of SE in distribution networks by placing additional physical meters. For state-of-the-art SE models, it is difficult to clearly quantify measurements' influences on SE errors, so the problems of optimal meter placement for reducing SE errors are mostly solved by heuristic or suboptimal algorithms....... Under this background, this paper proposes a circuit representation model to represent SE errors. Based on the matrix formulation of the circuit representation model, the problem of optimal meter placement can be transformed to a mixed integer linear programming problem (MILP) via the disjunctive model...

  12. Modelling and numerical simulation of the corrosion product transport in the pressurised water reactor primary circuit

    International Nuclear Information System (INIS)

    Marchetto, C.

    2002-05-01

    During operation of pressurised water reactor, corrosion of the primary circuit alloys leads to the release of metallic species such as iron, nickel and cobalt in the primary fluid. These corrosion products are implicated in different transport phenomena and are activated in the reactor core where they are submitted to neutron flux. The radioactive corrosion products are afterwards present in the out of flux parts of primary circuit where they generate a radiation field. The first part of this study deals with the modelling of the corrosion: product transport phenomena. In particular, considering the current state of the art, corrosion and release mechanisms are described empirically, which allows to take into account the material surface properties. New mass balance equations describing the corrosion product behaviour are thus obtained. The numerical resolution of these equations is implemented in the second part of this work. In order to obtain large time steps, we choose an implicit time scheme. The associated system is linearized from the Newton method and is solved by a preconditioned GMRES method. Moreover, a time step auto-adaptive management based on Newton iterations is performed. Consequently, an efficient resolution has been implemented, allowing to describe not only the quasi-steady evolutions but also the fast transients. In a last step, numerical simulations are carried out in order to validate the new corrosion product transport modelling and to illustrate the capabilities of this modelling. Notably, the numerical results obtained indicate that the code allows to restore the on-site observations underlining the influence of material surface properties on reactor contamination. (author)

  13. VT VEC Primary Overhead and Underground Distribution Lines

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) Vermont Electric Cooperative, Inc. (VEC) Primary Overhead and Underground Distribution Lines. VEC’s Distribution lines were drawn from pole to...

  14. Current, voltage and temperature distribution modeling of light-emitting diodes based on electrical and thermal circuit analysis

    International Nuclear Information System (INIS)

    Yun, J; Shim, J-I; Shin, D-S

    2013-01-01

    We demonstrate a modeling method based on the three-dimensional electrical and thermal circuit analysis to extract current, voltage and temperature distributions of light-emitting diodes (LEDs). In our model, the electrical circuit analysis is performed first to extract the current and voltage distributions in the LED. Utilizing the result obtained from the electrical circuit analysis as distributed heat sources, the thermal circuit is set up by using the duality between Fourier's law and Ohm's law. From the analysis of the thermal circuit, the temperature distribution at each epitaxial film is successfully obtained. Comparisons of experimental and simulation results are made by employing an InGaN/GaN multiple-quantum-well blue LED. Validity of the electrical circuit analysis is confirmed by comparing the light distribution at the surface. Since the temperature distribution at each epitaxial film cannot be obtained experimentally, the apparent temperature distribution is compared at the surface of the LED chip. Also, experimentally obtained average junction temperature is compared with the value calculated from the modeling, yielding a very good agreement. The analysis method based on the circuit modeling has an advantage of taking distributed heat sources as inputs, which is essential for high-power devices with significant self-heating. (paper)

  15. Pressure Pump Power Control in the Primary Circuit of the Heat Exchange System

    Directory of Open Access Journals (Sweden)

    Shilin Aleksandr

    2017-01-01

    Full Text Available In this paper we consider the problem of speed in hot water systems where highly efficient plate heat exchanger is used. Especially marked the problem which is connected with long transition drive of constant speed exceeding the time of the heat exchanger accumulative tank emptying more than twice. As a regulating element in the heat exchange system there was proposed to use asynchronous electric drive of pressure pump in the primary circuit of the heat exchanger. For correct use of such electric drive we solved the problem of control object mathematical model synthesis, which has non-linear properties, in particular, the transfer coefficient of the circuit can vary in more than 6 times. At the same time there was revealed the dependence of the transfer coefficient on the motor speed, which must be considered in the controller synthesis. In conclusion we suggested the solutions of regulators synthesis tasks with customizable settings for speed and switchable structure between relay λ and PI regulators.

  16. Coolant clean-up system in the primary coolant circuit for nuclear reactor

    International Nuclear Information System (INIS)

    Saito, Michio.

    1981-01-01

    Purpose: To maintain the quality of coolants at a prescribed level by distillating coolants in the primary coolant circuit for a BWR type reactor to remove impurities therefrom, taking out the condensates from the top of the distillation column and extracting impurities in a concentrated state from the bottom. Constitution: Coolant water for cooling the core is recycled by a recycling pump by way of a recycling pipeway in a reactor. The coolants extracted from an extraction pipeway connected to the recycling pipeway are fed into a distillation column, where distillation is taken place. Impurities in the coolants, that is, in-core corrosion products, fission products generated in the reactor core, etc. are separated by the distillation, concentrated and solidified in the bottom of the distillation column. While on the other hand, condensates removed with the impurities, that is, coolants cleaned-up are recycled to the coolant water for cooling the reactor core. (Moriyama, K.)

  17. Operative modes of the primary circuit degasser of Atucha II N.P.P

    International Nuclear Information System (INIS)

    Rodriguez, Ivanna; Contino, Maximiliano; Chocron, Mauricio; Duca, Jorge

    2012-09-01

    Atucha II (N.A.S.A., Buenos Aires Province, Argentina) is a Pressurized Vessel Heavy Water Reactor designed by Siemens with a capacity of 740 MWe. After a long delay in construction the plant is close to the commissioning and among the many task that are carried out, chemistry and operation of devices related to it are under consideration [1]. As it is known, Hydrogen or Deuterium dosing has the purpose of both: limitation of the water radiolysis and to provide an appropriate reductive media for the structural materials, mainly stainless steel, A800 and Zr-4. Dealing with a heavy water plant, it is critical to determine whether it is necessary to add D 2 or if it is feasible to dose H 2 , by considering heavy water degradation and heavy water upgrading system capability. Those aspects have been previously analyzed and presented [2]. It is also necessary to consider blankets and venting locations that address to losses of the expensive D 2 . In the present work several alternatives of hydrogenation are presented and evaluated, considering the Degasser (D), the Volume Control Tank (TCV) and the special features of the purification and volume control system of a pressurized vessel heavy water plant where the primary circuit and moderator are partially mixed. Also the influence of venting through the pressurizer is analyzed. Conclusions are obtained in connection to (i) the maintenance of a permanent blanket of H 2 /He, 4%, in the TCV dome at a given initial pressure, (ii) The same but constant pressure to reach 0.6 ppm of H 2 in the Primary and Moderator water circuit, (iii) transients while reducing pressure in the Degasser and considering contribution of pressurizer venting, (iv) estimated contribution of the general corrosion of the system and (iv) differences if D 2 is used. (authors)

  18. Primary circuit and reactor core T-H characteristics determination of WWER 440 reactors

    International Nuclear Information System (INIS)

    Hermansky, J.; Petenyi, V.; Zavodsky, M.

    2010-01-01

    The WWER-440 nuclear fuel vendor permanently improves the assortment of produced nuclear fuel assemblies for achieving better fuel cycle economy and reactor operation safety. During unit refuelling there also could be made some other changes in hydraulic parameters of primary circuit (change of impeller wheels, hydraulic resistance coefficient changes of internal parts of primary circuit, etc.). Therefore it is necessary to determine real coolant flow rate through the reactor during units start-up after their refuelling, and also to have the skilled methodology and computing code for analyzing factors, which affecting the inaccuracy of coolant flow redistribution determination through reactor on flows through separate parts of reactor core in any case of parallel operation of different assembly types. Computing code TH-VCR and CORFLO are used for reactor core characteristics determination for one type of fuel and control assemblies and also in case of parallel operation of different assembly types. The code TH-VCR is able to calculate coolant flow rate for different combinations of three different fuel assembly channel types and three different control assembly channel types. The CORFLO code deals the area of the reactor core which consists of 312 fuel assemblies and 37 control assemblies. Regarding the rotational 60 deg symmetry of reactor core only 1/6 of reactor core with 59 fuel assemblies is taken into account. Computing code CORFLO is verified and validated at this time. Paper presents some results from measurements of coolant flow rate through reactors during start-up after unit refuelling and short description of computing code TH-VCR and CORFLO with some calculated results. (Authors)

  19. Pain distribution in primary care patients with hip osteoarthritis

    DEFF Research Database (Denmark)

    Poulsen, Erik; Overgaard, Søren; Vestergaard, Jacob T

    2016-01-01

    BACKGROUND: Hip osteoarthritis (OA) is the most common diagnosis in primary care adult patients presenting with hip pain but pain location and pain distribution in primary care patients with hip OA have been reported inadequately. OBJECTIVE: To describe pain location and pain distribution...

  20. On steady-state concentrations of ammonia and molecular hydrogen in the primary circuit of the WWER-1000 reactors

    International Nuclear Information System (INIS)

    Arkhipov, O.P.; Bugaenko, V.L.; Kamakchi, S.A.

    1997-01-01

    It is shown that the MORAVA-N2 software package describes well the coolant state in the primary circuit of an actual reactor facility with the WWER-1000 during on-load operation. It permits using the package for analysis of process perturbation effect on the coolant composition. Specific feature of ammonia radiation chemistry in the primary circuit of a reactor facility with the WWER-1000, assuring the rates hydrogen concentration in the coolant with ammonia concentration variation in the coolant within wide limits, when reactor operates on power, can be mentioned by way of example, the fact being ascertained in this study

  1. Estimation of Operating Condition of Appliances Using Circuit Current Data on Electric Distribution Boards

    Science.gov (United States)

    Iwafune, Yumiko; Ogimoto, Kazuhiko; Yagita, Yoshie

    The Energy management systems (EMS) on demand sides are expected as a method to enhance the capability of supply and demand balancing of a power system under the anticipated penetration of renewable energy generation such as Photovoltaics (PV). Elucidation of energy consumption structure in a building is one of important elements for realization of EMS and contributes to the extraction of potential energy saving. In this paper, we propose the estimation method of operating condition of household appliances using circuit current data on an electric distribution board. Circuit current data are broken down by their shape using a self-organization map method and aggregated by appliance based on customers' information of appliance possessed. Proposed method is verified using residential energy consumption measurement survey data.

  2. Application of surface science to the study of the corrosion of PWR primary circuit materials

    International Nuclear Information System (INIS)

    Harris, S.J.

    1989-04-01

    This thesis describes a study of the corrosion and oxidation of PWR primary circuit materials using surface sensitive spectroscopic techniques. An X-ray photoemission spectroscopy (XPS) study of a number of mixed oxides of known composition is described and the information obtained is related to XPS measurements made on the surface of iron and nickel based alloys oxidised under controlled conditions. A secondary ion mass spectroscopy (SIMA) study on these mixed transition metal oxides is also described. The gaseous oxidation of stainless steel 3041 and Inconel-690 is examined. Both alloys were oxidised at 600K in air with the composition of the oxide films formed studied by a range of surface spectroscopic methods. Further experimental work was performed on Inconel-690 to examine the effects of surface pretreatment and the effects of low oxygen partial pressures on the formation of oxide films at 600 K. The incorporation of the radionuclide, cobalt-60, into the oxide films formed on structural components of a PWR, result in the build up of radiation fields. A method of pretreating the surface of the alloy stainless steel 3041, in order to reduce the level of cobalt adsorbed into the oxide film formed under simulated primary coolant conditions is examined and contrasts with treatments which have been developed to release cobalt adsorbed in existing oxide layers under reactor conditions are discussed. (author)

  3. Importance of ECP in the prediction of radiation fields in PWR and VVER primary circuits

    International Nuclear Information System (INIS)

    Urquidi-Macdonald, M.; Jacesko, S.L.; Macdonald, Digby D.; Salter-Williams, M.

    2002-01-01

    A model has been developed for predicting mass and activity transport in the primary coolant circuits of PWRs and VVERs with the objective of demonstrating and quantifying the importance of the electrochemical corrosion potential (ECP) in determining the impact of both processes on reactor operation. The model initially employs a radiolysis/mixed potential code to calculate the ECP at four locations (core, hot leg, steam generator, cold leg) and the ECP is then used to estimate the local magnetite solubility. The solubility is then averaged around the loop to yield the ''background'' solubility. Comparison of the background solubility with the local solubility determines whether precipitation or dissolution will occur at any given point in the circuit under any given set of conditions. It is further assumed that the concentration of 59 Co in the coolant is given by the isotopic fraction of this species compared with iron averaged over all materials and weighted by the respective wetted areas. Activation of 59 Co to 60 Co is assumed to occur in the coolant phase by fast, epithermal, and thermal neutron capture. The calculated activity is then used to train an artificial neural network (ANN) to establish relationships between activity at any given location and the operating properties of the reactor, including coolant pH, ECP, temperature, power level, etc. The model predicts that during shut down, magnetite (and hence 59 Co) migrates to the core, where it is irradiated and activated, particularly during subsequent start-up. During start-up, the magnetite (and hence 60 Co) migrates from the core to out-of-core surfaces where it establishes the radiation fields. (authors)

  4. Possibilities for the reduction of the activity build-up in the primary circuit of water-cooled nuclear reactors

    International Nuclear Information System (INIS)

    Sachse, G.; Mittag, I.

    1985-01-01

    Basing upon the international literature in a review are refered: research and development efforts; release, transport and deposition of radioactive corrosion products under primary circuit conditions; experimental results in test and technical systems; and possibilities to control radiation fields in nuclear power plants by waterchemical measures, decontamination, and high temperature filtration. Relevant patents are summarized. (author)

  5. Modulation of distributed feedback (DFB) laser diode with the autonomous Chua's circuit: Theory and experiment

    Science.gov (United States)

    Talla Mbé, Jimmi Hervé; Woafo, Paul

    2018-03-01

    We report on a simple way to generate complex optical waveforms with very cheap and accessible equipments. The general idea consists in modulating a laser diode with an autonomous electronic oscillator, and in the case of this study, we use a distributed feedback (DFB) laser diode pumped with an electronic Chua's circuit. Based on the adiabatic P-I characteristics of the laser diode at low frequencies, we show that when the total pump is greater than the laser threshold, it is possible to convert the electrical waveforms of the Chua's circuit into optical carriers. But, if that is not the case, the on-off dynamical behavior of the laser permits to obtain many other optical waveform signals, mainly pulses. Our numerical results are consistent with experimental measurements. The work presents the advantage of extending the range of possible chaotic dynamics of the laser diodes in the time domains (millisecond) where it is not usually expected with conventional modulation techniques. Moreover, this new technique of laser diodes modulation brings a general benefit in the physical equipment, reduces their cost and congestion so that, it can constitute a step towards photonic integrated circuits.

  6. Fission products distributions in Candu primary heat transport and Candu containment systems during a severe accident

    International Nuclear Information System (INIS)

    Constantin, Marin; Rizoiu, Andrei

    2005-01-01

    The paper is intended to analyse the distribution of the fission products (FPs) in CANDU Primary Heat Transport (PHT) and CANDU Containment Systems by using the ASTEC code (Accident Source Term Evaluation Code). The complexity of the data required by ASTEC and the complexity both of CANDU PHT and Containment System were strong motivations to begin with a simplified geometry in order to avoid the introducing of unmanageable errors at the level of input deck. Thus only 1/4 of the PHT circuit was simulated and a simplified FPs inventory, some simplifications in the feeders geometry and containment were used. The circuit consists of 95 horizontal fuel channels connected to 95 horizontal out-feeders, then through vertical feeders to the outlet-header (a big pipe that collects the water from feeders); the circuit continues from the outlet-header with a riser and then with the steam generator and a pump. After this pump, the circuit was broken; in this point the FPs are transferred to the containment. The containment model consists of 4 rooms connected between by 6 links. The data related to the nodes' definitions, temperatures and pressure conditions were chosen as possible as real data from CANDU NPP loss of coolant accident sequence. Temperature and pressure conditions in the time of the accident were calculated by the CATHENA code and the source term of FPs introduced into the PHT was estimated by the ORIGEN code. The FPs distribution in the nodes of the circuit and the FPs mass transfer per isotope and chemical species are obtained by using SOPHAEROS module of ASTEC code. The distributions into the containment are obtained by the CPA module of ASTEC code (thermalhydraulics calculations in the containment and FPs aerosol transport). The results consist of mass distributions in the nodes of the circuit and the transferred mass to the containment through the break for different species (FPs and chemical species) and mass distributions in the different parts and

  7. The primary visual cortex in the neural circuit for visual orienting

    Science.gov (United States)

    Zhaoping, Li

    The primary visual cortex (V1) is traditionally viewed as remote from influencing brain's motor outputs. However, V1 provides the most abundant cortical inputs directly to the sensory layers of superior colliculus (SC), a midbrain structure to command visual orienting such as shifting gaze and turning heads. I will show physiological, anatomical, and behavioral data suggesting that V1 transforms visual input into a saliency map to guide a class of visual orienting that is reflexive or involuntary. In particular, V1 receives a retinotopic map of visual features, such as orientation, color, and motion direction of local visual inputs; local interactions between V1 neurons perform a local-to-global computation to arrive at a saliency map that highlights conspicuous visual locations by higher V1 responses. The conspicuous location are usually, but not always, where visual input statistics changes. The population V1 outputs to SC, which is also retinotopic, enables SC to locate, by lateral inhibition between SC neurons, the most salient location as the saccadic target. Experimental tests of this hypothesis will be shown. Variations of the neural circuit for visual orienting across animal species, with more or less V1 involvement, will be discussed. Supported by the Gatsby Charitable Foundation.

  8. Improvement and qualification of ultrasonic testing of dissimilar welds in the primary circuit of NPPs

    International Nuclear Information System (INIS)

    Mitzscherling, Steffen; Barth, Enrico; Homann, Tobias; Prager, Jens; Goetschel, Sebastian; Weiser, Martin

    2017-01-01

    The austenitic and dissimilar welds found in the primary circuit of nuclear power plants are not only extremely relevant to safety but also place very high demands on material testing. In addition to limited accessibility, the macroscopic structure of the weld seam is of paramount importance for ultrasound testing. In order to reliably determine material errors in position and size, the grain orientations and the elastic constants of the anisotropic weld bead structure must be known. The following work steps are used for the imaging representation of possible material defects: First, the weld seam is sounded in order to be able to determine important weld seam parameters, such as, for example, the grain orientation, using an inverse method. On the basis of these parameters, the sound paths are simulated in the next step by means of raytracing (RT). Finally, this RT simulation is assigned the measurement data (A-scans) from different transmitter and receiver positions and superimposed according to the Synthetic Aperature Focusing Technique (SAFT) method. The combination of inverse process, RT and SAFT also ensures a correct visualization of the faults in anisotropic materials. We explain these three methods and present the test arrangement of test specimens with artificial test errors. Measurement data as well as their evaluation are compared with the results of a CIVA simulation. [de

  9. On aging factors, aging mechanisms and their combinations in the primary circuit of NPPs

    International Nuclear Information System (INIS)

    Varga, T.; Brumovsky, M.

    1993-01-01

    Ageing is the dominating problem of elder nuclear power plant (NPP) components but still can not be neglected even for the newest ones. Ageing may express itself in different ways: irradiated steel parts may become embrittled, chromium alloy steels may decompose, fatigue life may become exhausted so that cracks may be formed and finally, corrosion attack may result in stress corrosion cracking. However, even synthetics and rubber parts may become inelastic, swell, shrink or crack, electric contacts may be oxydised, or isolations may lose their high electric resistance. Therefore, experts in the different components and their materials have collected and published not only plenty of observations, but also a number of more or less systematic approaches. A general picture, however, still seems to be lacking, due to the fact that ageing factors and mechanisms are not defined and used properly, i.e. - ageing factors act because of the service conditions of the components, as well as the characteristics of the materials which provoke ageing mechanisms - ageing mechanisms cause the changing of properties of the materials involved - combinations of single ageing mechanisms, which can be double, triple or multiple, change and accelerate the ageing process - the consequence of ageing mechanisms is the altering of the properties of the material depending on the lifetime. In this paper we shall try to show a systematic approach to a potential ageing analysis concerning the main metallic components of primary circuits of NPP's - connection between ageing factors, ageing mechanisms and their consequences/effects on component behaviour

  10. A computer analysis code of radioactive corrosion product behaviour in primary circuits of LMFBRs (PSYCHE)

    International Nuclear Information System (INIS)

    Iizawa, Katsuyuki; Seki, Seiichi; Kawasaki, Yuji; Kano, Shigeki; Nihei, Isao

    1986-01-01

    Recently it has become an important subject to reduce exposure to radiation from radioactive corrosion products (CPs) during maintenance and repair works in reactor plants. Metallic sodium is used as cooling material in fast reactor plants, leading to different CP behaviours compared to light water reactors. In the present study, a computer code for analyzing behaviours of CPs in fast reactor plants is developed. The analysis code, called PSYCHE, makes it possible to perform consistent analysis of production, migration and deposition of CPs in primary circuits together with dose rate around piping of apparatus in cooling systems. An analysis model is developed based on test results on CP behaviour in out-pile sodium. The model, called the ''dissolution-deposition model'', can reproduce atom-selective behaviour, transient phenomenon and downstream effect of CPs, which represent mass transfer phenomena in sodium. Verification of this code is carried out on the basis of CP measurements made in ''Joyo''. The calculation vs. measurement ratio is found to be 0.5 - 2 for CP deposition density in piping for cooling systems and 0.7 - 1.3 for dose rate, demonstrating that this code can give reasonable results. Analysis is also made to predict future changes in total amount of deposited CP in ''Joyo''. (Nogami, K.)

  11. Theoretical approach to description of some corrosion product transport processes in PWRs primary circuit

    International Nuclear Information System (INIS)

    Zmitko, M.

    1990-10-01

    The behavior and mass transport of corrosion products in primary circuits of PWR type reactors are described assuming that the products occur in ionic form, in colloidal form (about 0.01-0.6 μm in size) and in particulate form. The transport of the soluble form is treated as a diffusion process. For the colloidal form, allowance is made for its Van der Waals attraction and repulsion interaction with the surfaces. For particles and their agglomerates, the hydrodynamical effects of the flowing liquid on the agglomerate breakdown and re-formation of the particle suspension are taken into account. Efforts were made to employ theoretical relations rather than particular experimental data, for the conclusions to be applicable to different facilities. It is believed that the complex approach to the problem can contribute to gaining insight into the role of the individual factors and processes involved, particularly as regards colloidal particles whose effect on the formation of radiation fields is not yet fully understood. (author). 3 figs., 10 refs

  12. Organization of Estrogen-Associated Circuits in the Mouse Primary Auditory Cortex

    Directory of Open Access Journals (Sweden)

    Liisa A. Tremere

    2011-01-01

    Full Text Available Sex steroid hormones influence the perceptual processing of sensory signals in vertebrates. In particular, decades of research have shown that circulating levels of estrogen correlate with hearing function. The mechanisms and sites of action supporting this sensory-neuroendocrine modulation, however, remain unknown. Here we combined a molecular cloning strategy, fluorescence in-situ hybridization and unbiased quantification methods to show that estrogen-producing and -sensitive neurons heavily populate the adult mouse primary auditory cortex (AI. We also show that auditory experience in freely-behaving animals engages estrogen-producing and -sensitive neurons in AI. These estrogen-associated networks are greatly stable, and do not quantitatively change as a result of acute episodes of sensory experience. We further demonstrate the neurochemical identity of estrogen-producing and estrogen-sensitive neurons in AI and show that these cell populations are phenotypically distinct. Our findings provide the first direct demonstration that estrogen-associated circuits are highly prevalent and engaged by sensory experience in the mouse auditory cortex, and suggest that previous correlations between estrogen levels and hearing function may be related to brain-generated hormone production. Finally, our findings suggest that estrogenic modulation may be a central component of the operational framework of central auditory networks.

  13. Applying wind turbines and battery storage to defer Orcas Power and Light Company distribution circuit upgrades

    International Nuclear Information System (INIS)

    Zaininger, H.W.; Barnes, P.R.

    1997-03-01

    The purpose of this study is to conduct a detailed assessment of the Orcas Power and Light Company (OPALCO) system to determine the potential for deferring the costly upgrade of the 25-kV Lopez- Eastsound circuit, by the application of a MW-scale wind farm and battery storage facilities as appropriate. Local wind resource data has been collected over the past year and used to determine MW-scale wind farm performance. This hourly wind farm performance data is used with measured hourly Eastsound load data, and recent OPALCO distribution system expansion plans and cost projections in performing this detailed benefit-cost assessment. The OPALCO distribution circuit expansion project and assumptions are described. MW-scale wind farm performance results are given. The economic benefit-cost results for the wind farm and battery storage applications on the OPALCO system using OPALCO system design criteria and cost assumptions are reported. A recalculation is presented of the benefit-cost results for similar potential wind farm and battery storage applications on other utility systems with higher marginal energy and demand costs. Conclusions and recommendations are presented. costs. Conclusions and recommendations are presented

  14. Assessment of the heat carrier movement in the primary coolant circuit by its own momentum

    International Nuclear Information System (INIS)

    Kadalev, Stoyan

    2014-01-01

    Highlights: • We model the heat carrier flow alteration after the circulation pump(s) stop. • The general mathematical model used is described in details. • The model is adapted and applied to a particular example research reactor. • Assessment is presented in detail, step by step with references. • The information provided is enough to apply calculations to another facility. - Abstract: In the presented paper is considered the approach to an assessment of the heat carrier flow alteration in the primary water–water reactor coolant circuit after the circulation pump(s) stop. This topic is highly relevant trough advanced and increased nuclear safety requirements because such a process is observed in case of black-out accident or damaged pump(s). The general mathematical model used is described; enabling preparation of this evaluation adapted and applied to a particular example facility namely a pool type research reactor. The factors influencing to the heat carrier movement by its own momentum are examined. The evaluation measures and includes the factors influencing the heat carrier flow rate from the moment the pump(s) stops down to a negligible value. Assessment is presented in detail, step by step and where needed with references to specific data and/or formulae from reference books to allow repetition of the calculations and/or apply to another facility. The calculations are presented utilizing all necessary data according to the design and technological documentation. No account is given to the pressure of the natural circulation caused by the residual heat generation in the fuel after the reactor scram system extinction of the fission reaction

  15. The online sealing performance test of the primary circuit pressure boundary check valve in nuclear power plants

    International Nuclear Information System (INIS)

    Yang Yunfei; Huang Huimin

    2013-01-01

    The primary circuit pressure boundary check valves of 320 MW pressurized water reactor is a nuclear grade I key equipment. The sealing demand is very high, which is directly related to the internal leakage rate of the primary circuit system. After the welding check valve is repaired, the sealing performance is judged by color printing checks. If there is water or humid vapor in the pipe, it will affect the accuracy of the color printing checks. For the particularity of the online check valve tightness test, online detecting device is designed by the hydraulic pressure drop method in other nuclear power plants, but the method has some shortcomings and restrictions. In this paper, we design a reliable and portable test equipment by the low-pressure gas seal test flow measurement, which make accurate and quantitative judgment of sealing property after the pressure boundary check valves are repaired. (authors)

  16. Thermal-hydraulic model of the primary coolant circuits for the full-scale training facility with WWER-1000

    International Nuclear Information System (INIS)

    Kroshilin, A.E.; Zhukavin, A.P.; Pryakhin, V.N.

    1992-01-01

    The mathematical model realized in the full-scale educational facility for NPP operator training is described. The RETACT computational complex providing real time process simulation for all regimes including the maximum credible accident is used for calculation of thermohydraulic parameters of the primary coolant circuits and steam generator under stationary and transient conditions. The two-velocity two-temperature model of one-dimensional steam-water flow containing uncondensed gases is realized in the program

  17. EDF operational experience of primary circuit filter usage. Analysis of results and strategy for optimizing filtration and reducing solid wastes

    International Nuclear Information System (INIS)

    Mascarenhas, Darren; Moleiro, Edgar; Bancelin, Estelle; Bretelle, Jean-Luc

    2014-01-01

    Pleated fibreglass media filter cartridges are used throughout the auxiliary systems at nuclear power plants across the 58 reactors of EDF fleet. The main role of these filters is to remove suspended solids from coolant to prevent them accumulating in circuits or in equipments. In the primary circuit, these filters therefore limit the deposition of solids that are active or could become active if allowed to recirculate throughout the primary circuit, avoiding potential consequences such as an increase in dose rates, axial offset anomalies, demineralisers fouling, higher pressure losses in primary loop, and clogging of the primary pumps. Since 2008, a steady increase in the consumption of filters has been noticed, and therefore an increase in the amount of solid waste to treat. Preliminary studies have identified the primary circuit high-flow filters of the 1300/1450 MWe reactors as the main source of this increase. Not only has this stretched of solid waste containers production to the limit, as well as strained site resources and increased risks of operational errors during periods of frequent filter changes; it has also suggested that there is an underlying problem that could pose a serious risk to the primary circuit if untreated. Further studies have been carried out to identify more precisely the impact of possible causes, including increased quality surveillance of the filters, correlation of consumption data with the concentrations of various conditioning products and typical pollutants, and an impact analysis of events such as steam generator replacements or new practices like zinc injection. Work has been done with the filter manufacturer to improve their service lifetime and a simulation tool has been developed in order to understand and optimise filtration. We are also working with sites on creating good practices and avoiding bad ones. These actions should reduce the consumption in the short term while still assuring a high quality of filtration and

  18. Analysis of a distributed pulse power system using a circuit analysis code

    International Nuclear Information System (INIS)

    Hoeft, L.O.; BDM Corp., Albuquerque, NM)

    1979-01-01

    A sophisticated computer code (SCEPTRE), used to analyze electronic circuits, was used to evaluate the performance of a large flash x-ray machine. This device was considered to be a transmission line whose impedance varied with position. This distributed system was modeled by lumped parameter sections with time constants of 1 ns. The model was used to interpret voltage, current, and radiation measurements in terms of diode performance. The effects of tube impedance, diode model, switch behavior, and potential geometric modifications were determined. The principal conclusions were that, since radiation output depends strongly on voltage, diode impedance was much more important than the other parameters, and the charge voltage must be accurately known

  19. Raman distributed sensor system for temperature monitoring and leak detection in sodium circuits of FBR

    Energy Technology Data Exchange (ETDEWEB)

    Pandian, C.; Kasinathan, M.; Sosamma, S.; Babu Rao, C.; Jayakumar, T.; Murali, N.; Paunikar, V.; Kumar, S.; Rajan, K. K.; Raj, B. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2009-07-01

    Leak detection in coolant loops of nuclear reactors is critical for the safety and performance of the reactors. The feasibility of using Raman distributed temperature sensor (RDTS) has been studied on a 30 m test loop. Temperature in sodium circuits of fast Breeder Reactor (FBR) exceeds 550 C degrees, gold coated fiber is chosen as sensor fibers. Leak is simulated through an artificial micro fissure integrated in the test loop with provision for controlled leak rate. The results are discussed in the paper. The temperature response of RDTS is compared to the conventional thermocouple and their performance was found comparable. The feasibility of detecting the temperature differential of a controlled leak with RDTS is demonstrated

  20. Highly localized distributed Brillouin scattering response in a photonic integrated circuit

    Science.gov (United States)

    Zarifi, Atiyeh; Stiller, Birgit; Merklein, Moritz; Li, Neuton; Vu, Khu; Choi, Duk-Yong; Ma, Pan; Madden, Stephen J.; Eggleton, Benjamin J.

    2018-03-01

    The interaction of optical and acoustic waves via stimulated Brillouin scattering (SBS) has recently reached on-chip platforms, which has opened new fields of applications ranging from integrated microwave photonics and on-chip narrow-linewidth lasers, to phonon-based optical delay and signal processing schemes. Since SBS is an effect that scales exponentially with interaction length, on-chip implementation on a short length scale is challenging, requiring carefully designed waveguides with optimized opto-acoustic overlap. In this work, we use the principle of Brillouin optical correlation domain analysis to locally measure the SBS spectrum with high spatial resolution of 800 μm and perform a distributed measurement of the Brillouin spectrum along a spiral waveguide in a photonic integrated circuit. This approach gives access to local opto-acoustic properties of the waveguides, including the Brillouin frequency shift and linewidth, essential information for the further development of high quality photonic-phononic waveguides for SBS applications.

  1. Components of the primary circuit of LWRs. Design, construction and calculation. Komponenten des Primaerkreises von Leichtwasserreaktoren. Auslegung, Konstruktion und Berechnung

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    This standard is to be applied to components made of metallic materials, operated at design temperatures of up to 673 K (400 C). The primary circuit as the pressure containment of the reactor coolant comprises: Reactor pressure vessel (without internals), steam generator (primary loop), pressurizer, reactor coolant pump housing, interconnecting pipings between the components mentioned above and appropriate various valve and instrument casings, pipings branding from the above components and interconnecting pipings, including the appropriate instrument casings, up to and including the first isolating valve, pressure shielding of control rod drives.

  2. 3D modeling of the primary circuit in the reactor pressure vessel of a PHWR

    Energy Technology Data Exchange (ETDEWEB)

    Ramajo, Damian, E-mail: dramajo@santafe-conicet.gov.ar; Corzo, Santiago; Schiliuk, Nicolas; Nigro, Norberto

    2013-12-15

    A computational fluid dynamics (CFD) simulation of the reactor pressure vessel (RPV) of the pressurized heavy water reactor (PHWR) of 745 electrical MW Atucha II nuclear power plant was carried out. A three dimensional (3D) detailed model was employed to simulate coolant circuit considering the upper and lower plenums, the downcomer and the hot and cold legs. Control rods and coolant channel tubes at the upper plenum were included to quantify the mixing flow with more realism. The whole set of 451 coolant channels were modeled by means of a zero dimensional methodology. That is, the effect of each coolant channel was modeled through the introduction of a source point at the upper plenum and a sink point at the lower plenum. For each coupled sink/source points (SSP) the mass, momentum and energy balance were solved considering the local pressure difference and the temperature between the corresponding points where sinks and sources were placed. Based on this strategy, three models with increasingly level of approximation were implemented. For the first model the 451 coolant channels were reduced to only 57 pairs of SSP to represent all the coolant channels, concentrating the effect of several coolant channels in a unique pair of sink and source while taking into account geometric design details. For the second model, 225 pairs of SSP were introduced. Finally, for the third model each one of the 451 coolant channels were modeled by means of one pair of SSP. Depending on the coolant channel location, the radial power distribution and the pressure loss caused by the corresponding flow restrictor present by design were considered. Simulations carried out give insight in the complexity of the flow. As expected, the greater the details of the model the better the accuracy reached in the representation of the RPV behavior. In addition, the flow distributor located at the lower plenum showed to be very efficient since, the mass flow at each channel was found to be fairly

  3. Teachers' reflections on distributive leadership in public primary ...

    African Journals Online (AJOL)

    The findings revealed that leadership in Soweto primary schools is rooted in classical leadership practices and that any potential for the practice of distributive leadership is hindered by autocratic styles of leadership, hierarchical structures, and non-participative decision-making. Keywords: Activity Theory, collective ...

  4. Distributed Practice and Retrieval Practice in Primary School Vocabulary Learning

    NARCIS (Netherlands)

    N.A.M.C. Goossens (Nicole)

    2015-01-01

    markdownabstractThe aim of this thesis was to investigate whether particular memory strategies stemming from cognitive and educational psychology, enhance primary school vocabulary learning. Th e memory strategies investigated in this thesis were distributed practice and retrieval practice. Th e

  5. Primary sclerosing cholangitis and disease distribution in inflammatory bowel disease.

    LENUS (Irish Health Repository)

    O'Toole, Aoibhlinn

    2012-04-01

    The relationship between site of intestinal inflammation and primary sclerosing cholangitis (PSC) development in inflammatory bowel disease (IBD) has not been studied extensively, but may be important in understanding the pathogenesis of PSC. We aimed to determine patterns of disease distribution in IBD patients with and without PSC.

  6. Entanglement distribution schemes employing coherent photon-to-spin conversion in semiconductor quantum dot circuits

    Science.gov (United States)

    Gaudreau, Louis; Bogan, Alex; Korkusinski, Marek; Studenikin, Sergei; Austing, D. Guy; Sachrajda, Andrew S.

    2017-09-01

    Long distance entanglement distribution is an important problem for quantum information technologies to solve. Current optical schemes are known to have fundamental limitations. A coherent photon-to-spin interface built with quantum dots (QDs) in a direct bandgap semiconductor can provide a solution for efficient entanglement distribution. QD circuits offer integrated spin processing for full Bell state measurement (BSM) analysis and spin quantum memory. Crucially the photo-generated spins can be heralded by non-destructive charge detection techniques. We review current schemes to transfer a polarization-encoded state or a time-bin-encoded state of a photon to the state of a spin in a QD. The spin may be that of an electron or that of a hole. We describe adaptations of the original schemes to employ heavy holes which have a number of attractive properties including a g-factor that is tunable to zero for QDs in an appropriately oriented external magnetic field. We also introduce simple throughput scaling models to demonstrate the potential performance advantage of full BSM capability in a QD scheme, even when the quantum memory is imperfect, over optical schemes relying on linear optical elements and ensemble quantum memories.

  7. Modelling of Transport of Radioactive Substances in the Primary Circuit of Water Cooled Reactors

    International Nuclear Information System (INIS)

    2012-03-01

    coordinated research project (CRP) was proposed to determine the accuracy of existing computer codes and to identify how they could be improved through application of this body of work. Specifically, the CRP was expected to: - Build a database for selected pressurized water reactor (PWR) plants that would contain the design information suitable for their description within a computer code, as well as give the operating history of the plant, which would include the water chemistry data over several refuelling cycles; - Show the contamination of selected out-of-core surfaces such as circulating loops and steam generator channel heads versus operating history and compare the prediction of surface contamination versus time from modern radioactivity transport codes with actual plant data in a blind benchmarking exercise; - Determine how current codes, as well as new ones, could be improved and encourage the development of accurate new codes in Member States using the recommendations from the present work. This report uses as its basis the results of this CRP on 'Modelling of Transport of Radioactive Substances in the Primary Circuit of Water Cooled Reactors', which was conducted over the period 1996-2001 for PWR type reactors. The report also describes the significant progress demonstrated in this field in the period that followed.

  8. Predicted Variations of Water Chemistry in the Primary Coolant Circuit of a Supercritical Water Reactor

    International Nuclear Information System (INIS)

    Yeh, Tsung-Kuang; Wang, Mei-Ya; Liu, Hong-Ming; Lee, Min

    2012-09-01

    In response to the demand over a higher efficiency for a nuclear power plant, various types of Generation IV nuclear reactors have been proposed. One of the new generation reactors adopts supercritical light water as the reactor coolant. While current in-service light water reactors (LWRs) bear an average thermal efficiency of 33%, the thermal efficiency of a supercritical water reactor (SCWR) could generally reach more than 44%. For LWRs, the coolants are oxidizing due to the presence of hydrogen peroxide and oxygen, and the degradation of structural materials has mainly resulted from stress corrosion cracking. Since oxygen is completely soluble in supercritical water, similar or even worse degradation phenomena are expected to appear in the structural and core components of an SCWR. To ensure proper designs of the structural components and suitable selections of the materials to meet the requirements of operation safety, it would be of great importance for the design engineers of an SCWR to be fully aware of the state of water chemistry in the primary coolant circuit (PCC). Since SCWRs are still in the stage of conceptual design and no practical data are available, a computer model was therefore developed for analyzing water chemistry variation and corrosion behavior of metallic materials in the PCC of a conceptual SCWR. In this study, a U.S. designed SCWR with a rated thermal power of 3575 MW and a coolant flow rate of 1843 kg/s was selected for investigating the variations in redox species concentration in the PCC. Our analyses indicated that the [H 2 ] and [H 2 O 2 ] at the core channel were higher than those at the other regions in the PCC of this SCWR. Due to the self-decomposition of H 2 O 2 , the core channel exhibited a lower [O 2 ] than the upper plenum. Because the middle water rod region was in parallel with the core channel region with relatively high dose rates, the [H 2 ] and [H 2 O 2 ] in this region were higher than those in the other regions

  9. Lessons learnt from the resin release into the primary circuit of the Fessenheim NPP unit 1 in January 2004. Impact on the nuclear safety

    International Nuclear Information System (INIS)

    Georgescu, M.

    2004-01-01

    On January the 24 th , at the Fessenheim NPP unit 1, a human error was committed during a boron demineralizer line-up, caused by lack of preparation. Consequently, a quantity of resin estimated at about 300 liters was released from this demineralizer, through its safety valve, into the head-tank of the chemical and volume control (CVC) system and after that, into the primary circuit. The incident had a real impact on the unit: the CVC filters were clogged, the seal injection flow of the primary circuit main pumps was lost, the primary circuit main pump 2 tripped four days after the incident, as the rate of the recirculated seal leak flow (downstream the seal 1) increased up to the automatic trip set point, the shaft of the running primary circuit feed pump was found seized into the rear hydrostatic bearing following the pump stop (after ten days of successful operation), the thimble plugs were jammed into their guide tubes, the small diameter pipes were plugged. The unit shutdown for over five months was necessary to clean the primary circuit components, repair or replace the affected equipment items and carry out inspections and tests. The reinforced unit in-service monitoring program, set up during the unit start-up, confirms that, up to now, the unit operation has not been adversely affected by the residual amounts of resin which subsist in certain areas of the primary circuit. Nevertheless, it remains to verify that, in the long term, these deposits will have no negative chemical effect in the potential confined areas, such as the thermal barriers of the primary circuit main pumps. Finally, the occurrence of this incident underlines, once more, the importance of normal operating activity preparing and checking. It also reveals the implementation of an ''unforgiving'' design change allowing the installation of a boron demineralizer safety valve having its outlet connected to the primary circuit. (orig.)

  10. Fission product chemistry and aerosol behaviour in the primary circuit of a pressurised water reactor under severe accident conditions

    International Nuclear Information System (INIS)

    Bowsher, B.R.

    1985-09-01

    Three key accident sequences are considered covering a representative range of different environments of pressure, flow, temperature history and degree of zircaloy oxidation, and their principle thermal hydraulic and physical characteristics affecting chemistry behaviour are identified. Inventories, chemical forms and timing of fission product release are summarized together with the major sources of structural materials and their release characteristics. Chemistry of each main fission product species is reviewed from available experimental and/or theoretical data. Studies modelling primary circuit fission product behaviour are reviewed. Requirements for further study are assessed. (UK)

  11. Application of the leak-before-break concept to the primary circuit piping of the Leningrad NPP

    Energy Technology Data Exchange (ETDEWEB)

    Eperin, A.P.; Zakharzhevsky, Yu.O.; Arzhaev, A.I. [and others

    1997-04-01

    A two-year Finnish-Russian cooperation program has been initiated in 1995 to demonstrate the applicability of the leak-before-break concept (LBB) to the primary circuit piping of the Leningrad NPP. The program includes J-R curve testing of authentic pipe materials at full operating temperature, screening and computational LBB analyses complying with the USNRC Standard Review Plan 3.6.3, and exchange of LBB-related information with emphasis on NDE. Domestic computer codes are mainly used, and all tests and analyses are independently carried out by each party. The results are believed to apply generally to RBMK type plants of the first generation.

  12. Improving the ALUeS diagnostic system for determining the coolant leak place from the WWER-440 primary circuit

    International Nuclear Information System (INIS)

    Markosyan, G.R.; Petrosyan, V.G.; Shakhverdyan, S.V.; Aslanyan, M.A.

    2000-01-01

    The new algorithm for localizing the leakage from the WWER-440 primary circuit, intended for operation in the Siemens ALUeS system, is proposed. The results of the algorithm realization in the leakage control system (the ALUeS system copy), installed at the Armenian NPP power unit-2, are presented. The leakage localization algorithm proposed was tested in other experiments. The leakage position in the majority of cases is determined exactly. Small (up to 5 m) deviations, the cause whereof were incorrect readings of the transducers, were observed [ru

  13. Water chemistry and corrosion control of cladding and primary circuit components. Proceedings of a technical committee meeting

    International Nuclear Information System (INIS)

    1999-12-01

    Corrosion is the principal life limiting degradation mechanism in nuclear steam supply systems, especially taking into account the trends to increase fuel burnup, thermal rate and cycle length. Primary circuit components of water cooled power reactors have an impact on Zr-based alloys behaviour due to crud (primary circuit corrosion products) formation, transport and deposition on heat transfer surfaces. Crud deposits influence water chemistry, radiation and thermal hydraulic conditions near cladding surface, and by this way-Zr-based alloy corrosion. During the last decade, significant improvements were achieved in the reduction of the corrosion and dose rates by changing the cladding material for one more resistant to corrosion or by the improvement of water chemistry conditions. However, taking into account the above mentioned tendency for heavier fuel duties, corrosion and water chemistry, control will remain a serious task to work with for nuclear power plant operators and scientists, as well as development of generally accepted corrosion model of Zr-based alloys in a water environment in a new millennium. Upon the recommendation of the International Working Group on Water Reactor Fuel Performance and Technology, water chemistry and corrosion of cladding and primary circuit components are in the focus of the IAEA activities in the area of fuel technology and performance. At present the IAEA performs two co-ordinated research projects (CRPs): on On-line High Temperature Monitoring of Water Chemistry and Corrosion (WACOL) and on Activity Transport in Primary Circuits. Two CRPs deal with hydrogen and hydride degradation of the Zr-based alloys. A state-of-the-art review entitled: 'Waterside Corrosion of Zirconium Alloys in Nuclear Power Plants' was published in 1998. Technical Committee meetings on the subject were held in 1985 (Cadarache, France), 1989 (Portland, USA), 1993 (Rez, Czech Republic). During the last few years extensive exchange of experience in

  14. Highly localized distributed Brillouin scattering response in a photonic integrated circuit

    Directory of Open Access Journals (Sweden)

    Atiyeh Zarifi

    2018-03-01

    Full Text Available The interaction of optical and acoustic waves via stimulated Brillouin scattering (SBS has recently reached on-chip platforms, which has opened new fields of applications ranging from integrated microwave photonics and on-chip narrow-linewidth lasers, to phonon-based optical delay and signal processing schemes. Since SBS is an effect that scales exponentially with interaction length, on-chip implementation on a short length scale is challenging, requiring carefully designed waveguides with optimized opto-acoustic overlap. In this work, we use the principle of Brillouin optical correlation domain analysis to locally measure the SBS spectrum with high spatial resolution of 800 μm and perform a distributed measurement of the Brillouin spectrum along a spiral waveguide in a photonic integrated circuit. This approach gives access to local opto-acoustic properties of the waveguides, including the Brillouin frequency shift and linewidth, essential information for the further development of high quality photonic-phononic waveguides for SBS applications.

  15. Design analysis of a lead–lithium/supercritical CO2 Printed Circuit Heat Exchanger for primary power recovery

    International Nuclear Information System (INIS)

    Fernández, Iván; Sedano, Luis

    2013-01-01

    Highlights: • A design for a PbLi/CO 2 (SC) Printed Circuit Heat Exchanger which optimizes the pressure drop performance is proposed. • Numerical analyses have been performed to optimize the airfoil fins shape and arrangement. • SiC is proposed as structural material and tritium permeation barrier for the PCHE. • The integrated flux is larger than expected and allows reducing the CO 2 mass flow in this sector of the power cycle. • A transport model has been developed to evaluate the permeation of tritium from the liquid metal to the secondary CO 2 . -- Abstract: One of the key issues for fusion power plant technology is the efficient, reliable and safe recovery of the power extracted by the primary coolants. An interesting design option for power conversion cycles based on Dual Coolant Breeding Blankets (DCBB) is a Printed Circuit Heat Exchanger, which is supported by the advantages of its compactness, thermal effectiveness, high temperature and pressure capability and corrosion resistance. This work presents a design analysis of a silicon carbide Printed Circuit Heat Exchanger for lead–lithium/supercritical CO 2 at DEMO ranges (4× segmentation)

  16. Study of colloidal particles behaviour in the PWR primary circuit conditions; Etude du comportement des particules colloidales dans les conditions physicochimiques du circuit primaire des reacteurs a eau sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Barale, M

    2006-12-15

    EDF wants to understand, model and limit primary circuit contamination of Pressurized Water Reactors by colloidal particles resulting from corrosion. The electrostatic behaviour of representative oxide particles (cobalt ferrite, nickel ferrite and magnetite) has been studied in primary circuit conditions with the influence of boric acid and lithium hydroxide. The isoelectric point (IEP) and the point of zero charge (PZC) of particles, measured between 5 C and 320 C, exhibit a minimum towards 200 C. The thermodynamic constants of the protonation equilibrium of surface sites were calculated. When boric acid is added, zeta potential and IEP decrease because of borate ions sorption. On the contrary, there is not effect of lithium ions. The modelling of these results under conditions representative of primary circuit shows that these oxides exhibit a negative surface charge, explaining their sorption and adhesion behaviour. (author)

  17. Mercury distribution characteristics in primary manganese smelting plants

    International Nuclear Information System (INIS)

    Back, Seung-Ki; Sung, Jin-Ho; Moon, Young-Hoon; Kim, Young-Hee; Seok, Kwang-Seol; Song, Geum-Ju; Seo, Yong-Chil

    2017-01-01

    The mercury (Hg) distribution characteristics were investigated in three primary manganese smelting plants in Korea for the assessment of anthropogenic Hg released. Input and output materials were sampled from each process, and Hg concentrations in the samples were analyzed. Among the input materials, the most mercury was found in the manganese ore (83.1–99.7%) and mercury was mainly released through fly ash or off gas, depending on the condition of off gas cleaning system. As off gas temperature decreases, proportion and concentration of emitted gaseous elemental mercury (Hg 0 ) in off gas decreases. Based on mass balance study from these three plants and national manganese production data, the total amount of mercury released from those Korean plants was estimated to 644 kg/yr. About half of it was emitted into the air while the rest was released to waste as fly ash. With the results of this investigation, national inventory for Hg emission and release could be updated for the response to Minamata Convention on Mercury. - Graphical abstract: 1. Lack of data on mercury (Hg) distribution in manganese smelters. 2. Mass distribution of Hg released from 3 plants (as normalized values) were made as follows by measurements. 3. Information of distribution of Hg in Manganese smelters would be used for emission in to air and releases to other streams for the nation and globe in UNEP mercury report. - Highlights: • The mass balance study by on-site measurement from primary manganese smelting plants was made at first time in the world. • Hg distribution and main input and release pathways of Hg from primary manganese smelting plants could be found as the first time. • Gas temperature in bag filter affects Hg behavior and speciation changes in APCDs. • National inventory of Hg emssion has been updated with new data. - Mercury distribution in manganese smelting plant was investigated as the first measurements at commercial plants in the world. National Hg release

  18. Study of the accumulation and distribution of the radioactivity in the cooling circuit of the BOR-60 reactor

    International Nuclear Information System (INIS)

    Kizin, V.D.; Konyashov, V.V.; Lisitsyn, E.S.; Polyakov, V.I.; Chechetkin, Yu.V.

    1976-04-01

    The results of measurements of the radioactivity of the coolant and the deposits in the primary circuit of the BOR-60 reactor during its five years of operation are discussed. The values calculated for the exposure dose rate from the piping system and the contribution of the γ-radiation from the corrosion and fission product nuclides are given. The efficiency of coolant draining from the pipes in reducing the dose rate is estimated. (orig.) [de

  19. Influence of decontamination of the WWER-440 primary circuit equipment on pressure drop in the reactor

    International Nuclear Information System (INIS)

    Kritsky, V.; Rodionov, Y.; Beresina, I.

    2003-01-01

    Over 40 reactor cycles at four WWER-440 type reactors have been analyzed in order to explain the increase of the pressure drop under certain combination of conditions. It is shown that the staff radiation exposure and the dose rate at first circuit segments are inversely correlated with the value of the pressure drop at the reactor, which is connected with the mechanism of redistribution of deposits and radioactive nuclides between the reactor and the rest part of the circuit. The influence of pH T on the formation of the dose rate from equipment and the change of pressure drop in the reactor WWER-440 is studied. The optimal range of pH T values for these parameters is determined to be 6.95-7.05 and these values are within the range of the water chemistry standards. The correlation between the changes of pressure drop and the number of decontaminated steam generators is established. This correlation shows that the pressure drop at the reactor grows with the increase of steam generators decontaminated during a preventive maintenance

  20. Primary circuit leak detection an application on PWR vessel head penetrations

    International Nuclear Information System (INIS)

    Loisy, F.; Germain, J.L.; Chauvel, L.

    1996-01-01

    In 1991, cracks were discovered and localized in the lower part of certain vessel head adapters in EDF PWR units. While awaiting the replacement of the vessel heads in question, EDF developed systems to enable continuous monitoring of vessel head penetration, by means of early detection of leaks. One of these systems in based on detection of water vapour in a confined space above the vessel head. The efficiency of the measurement chain is particularly dependent on dilution of the leakage in the confined space prior TO entry in the sampling circuit. The detection threshold for this method is on the order of 1.2 liters/hour for a dilution rate of 1500 rate of 1500 m 3 /h and a dew point of 22 deg C. This system has now been in operation on three 1300-MW PWR units for three years, and has proved to function satisfactorily. (authors)

  1. Improved high-frequency equivalent circuit model based on distributed effects for SiGe HBTs with CBE layout

    International Nuclear Information System (INIS)

    Sun Ya-Bin; Li Xiao-Jin; Zhang Jin-Zhong; Shi Yan-Ling

    2017-01-01

    In this paper, we present an improved high-frequency equivalent circuit for SiGe heterojunction bipolar transistors (HBTs) with a CBE layout, where we consider the distributed effects along the base region. The actual device structure is divided into three parts: a link base region under a spacer oxide, an intrinsic transistor region under the emitter window, and an extrinsic base region. Each region is considered as a two-port network, and is composed of a distributed resistance and capacitance. We solve the admittance parameters by solving the transmission-line equation. Then, we obtain the small-signal equivalent circuit depending on the reasonable approximations. Unlike previous compact models, in our proposed model, we introduce an additional internal base node, and the intrinsic base resistance is shifted into this internal base node, which can theoretically explain the anomalous change in the intrinsic bias-dependent collector resistance in the conventional compact model. (paper)

  2. Structural analysis and incipient failure detection of primary circuit components based on correlation-analysis and finite-element models

    International Nuclear Information System (INIS)

    Olma, B.J.

    1977-01-01

    A method is presented to compute vibrational power spectral densities (VPSD's) of primary circuit components based on a finite-element representation of the primary circuit. First this method has been applied to the sodium cooled reactor KNK, Karlsruhe. Now a further application is being developed for a BWR-nuclear power plant. The experimentally determined VPSD's can be considered as the output of a multiple input-output system. They have to be explained as the frequency response of a multidimensional mechanical system, which is excited by stochastic and deterministic mechanical driving forces. The stochastic mechanical forces are generated by the dynamic pressure fluctuations of the fluid. The deterministic mechanical forces are caused by the pressure fluctuations, which are induced by the main coolant pumps or by standing waves. The excitation matrix can be obtained from measured pressure fluctuations. The vibration transfer function matrix can be computed from the mass matrix, damping matrix and stiffness matrix of a theoretical finite-element model or mass-spring model. Based on this theory the computer code 'STAMPO' has been established. This program has been applied to the KNK reactor. The excitation matrix was created from measured jet-noise pressure fluctuations. The mass-, stiffness- and damping matrix has been extracted from a SAP-IV-model of the primary system. Sequentially for each frequency point the complete VPSD matrix has been computed. The diagonal elements of this matrix represent the vibrational auto-power spectral densities, the off-diagonal elements represent the vibrational cross-power spectral densities. The calculations give good agreement with measured VPSD's. The comparison shows that the measured jet-noise pressure fluctuations act nearly uncorrelated on the structure, whereas the output VPSD's are well correlated

  3. Modeling in fast dynamics of accidents in the primary circuit of PWR type reactors; Modelisation en dynamique rapide d'accidents dans le circuit primaire des reacteurs a eau pressurisee

    Energy Technology Data Exchange (ETDEWEB)

    Robbe, M.F

    2003-12-01

    Two kinds of accidents, liable to occur in the primary circuit of a Pressurized Water Reactor and involving fast dynamic phenomena, are analyzed. The Loss Of Coolant Accident (LOCA) is the accident used to define the current PWR. It consists in a large-size break located in a pipe of the primary circuit. A blowdown wave propagates through the circuit. The pressure differences between the different zones of the reactor induce high stresses in the structures of the lower head and may degrade the reactor core. The primary circuit starts emptying from the break opening. Pressure decreases very quickly, involving a large steaming. Two thermal-hydraulic simulations of the blowdown phase of a LOCA are computed with the Europlexus code. The primary circuit is represented by a pipe-model including the hydraulic peculiarities of the circuit. The main differences between both computations concern the kind of reactor, the break location and model, and the initialization of the accidental operation. Steam explosion is a hypothetical severe accident liable to happen after a core melting. The molten part of the core (called corium) falls in the lower part of the reactor. The interaction between the hot corium and the cold water remaining at the bottom of the vessel induces a massive and violent vaporization of water, similar to an explosive phenomenon. A shock wave propagates in the vessel. what can damage seriously the neighbouring structures or drill the vessel. This work presents a synthesis of in-vessel parametrical studies carried out with the Europlexus code, the linkage of the thermal-hydraulic code Mc3d dedicated to the pre-mixing phase with the Europlexus code dealing with the explosion, and finally a benchmark between the Cigalon and Europlexus codes relative to the Vulcano mock-up. (author)

  4. Experimental investigation of localized stress-induced leakage current distribution in gate dielectrics using array test circuit

    Science.gov (United States)

    Park, Hyeonwoo; Teramoto, Akinobu; Kuroda, Rihito; Suwa, Tomoyuki; Sugawa, Shigetoshi

    2018-04-01

    Localized stress-induced leakage current (SILC) has become a major problem in the reliability of flash memories. To reduce it, clarifying the SILC mechanism is important, and statistical measurement and analysis have to be carried out. In this study, we applied an array test circuit that can measure the SILC distribution of more than 80,000 nMOSFETs with various gate areas at a high speed (within 80 s) and a high accuracy (on the 10-17 A current order). The results clarified that the distributions of localized SILC in different gate areas follow a universal distribution assuming the same SILC defect density distribution per unit area, and the current of localized SILC defects does not scale down with the gate area. Moreover, the distribution of SILC defect density and its dependence on the oxide field for measurement (E OX-Measure) were experimentally determined for fabricated devices.

  5. Implementation of Complex Biological Logic Circuits Using Spatially Distributed Multicellular Consortia

    Science.gov (United States)

    Urrios, Arturo; de Nadal, Eulàlia; Solé, Ricard; Posas, Francesc

    2016-01-01

    Engineered synthetic biological devices have been designed to perform a variety of functions from sensing molecules and bioremediation to energy production and biomedicine. Notwithstanding, a major limitation of in vivo circuit implementation is the constraint associated to the use of standard methodologies for circuit design. Thus, future success of these devices depends on obtaining circuits with scalable complexity and reusable parts. Here we show how to build complex computational devices using multicellular consortia and space as key computational elements. This spatial modular design grants scalability since its general architecture is independent of the circuit’s complexity, minimizes wiring requirements and allows component reusability with minimal genetic engineering. The potential use of this approach is demonstrated by implementation of complex logical functions with up to six inputs, thus demonstrating the scalability and flexibility of this method. The potential implications of our results are outlined. PMID:26829588

  6. Welded joints engineering design of the primary circuit, surge line and main steam piping of the Angra 2 reactor

    International Nuclear Information System (INIS)

    Volta, Angelo Roberto; Couto, Jose Gonzalo Villaverde

    1995-01-01

    The erection of nuclear systems of a Nuclear Power Station is under international requests, that results in a detailed elaboration of documents for the performance of welds. NUCLEN as an engineering design company, responsible for the erection of Angra 2, developed a suitable software program for the elaboration of welding procedure qualifications, tests and examination sequence plans and heat treatment plans applied to primary circuit, surgeline and main steam piping. The paper shows the employed methodology for the elaboration of these documents, as well as the requested engineering design of welding technology and testability in order to assure the stipulated quality level, according to requirements of the specifications, codes and norms. (author). 6 refs

  7. Integral forged pump casing for the primary coolant circuit of a nuclear reactor: Development in design, forging technology, and material

    International Nuclear Information System (INIS)

    Austel, W.; Korbe, H.

    1986-01-01

    Developments in the forging of large casings for primary circuit coolant pumps for light water reactors in Germany are demonstrated beginning with the multiple forging fabricated version and ending with the integral forged type. This version is the result of the joint efforts of the pump manufacturer and the forgemaster after a cost-gain evaluation and represents an optimum solution in view of its functional and economical performance and also considering the high requirements for mechanical-technological properties, including homogeneity of the material. The development from 22 NiMoCr 3 7/A 508 Class 2 to 20 MnMoNi 5 5/A 508 Class 3 and their optimization will be demonstrated. This development is based mainly on minimizing the sulfur content and on vacuum carbon deoxidation (VCD), which results in a reduction of the A-segregations, in improving fracture toughness and isotropy, and in the desired fine-grain structure

  8. Chemical interactions between aerosols and vapors in the primary circuit of an LWR during a severe accident

    International Nuclear Information System (INIS)

    Wheatley, C.J.

    1988-01-01

    Aerosol formation, agglomeration, convection and deposition within the primary circuit of an LWR during a severe accident significantly affect the transport of fission products, even though they may compose only a small fraction of the aerosol material. Intra-particle and vapor chemical interactions are important to this through mass transfer between the aerosol and vapor. The authors will describe a model that attempts to account for these processes and of the two-way coupling that exists with the thermal hydraulics. They will discuss what agglomeration and deposition mechanisms must be included, alternatives for treating intra-particle chemical interactions, mechanisms of aerosol formation, and methods for solving the resulting equations. Results will be presented that illustrate the importance of treating the two-way coupling and the extent to which disequilibrium between the aerosol and vapor affects fission product behavior

  9. Development of new chemical and electrochemical decontamination methods for selected equipment of WWER-440 and WWER-1000 reactor primary circuit

    International Nuclear Information System (INIS)

    Solcanyi, M.; Majersky, D.

    1998-01-01

    Special devices for in-situ application of decontamination technologies assigned for Steam Generator, Pressurizer and Main Circulating Casing of WWER-1000 type were designed, manufactured and tested in real conditions of their use in above Primary Circuit components. New decontamination technologies like low-concentration process NP-NHN for the decontamination of the Steam Generator, combined chemico-mechanical treatment for the Pressurizer and semi-dry electrolysis for the Main Circulating Pump Casing were developed and approved for their safe plant application from point of view of decontamination efficiency, corrosion influence and processing of secondary wastes. Main technological parameters were defined to achieve high decontamination efficiency and corrosion-safe application of all decontamination technologies. (author)

  10. Study of aged embrittled stainless steels used in the primary circuit of fission reactors

    International Nuclear Information System (INIS)

    Hazarabedian, Alfredo

    1999-01-01

    We checked the damage and fracture mechanisms of duplex stainless steels aged in conditions representative of the actual operating condition of a PWR nuclear power plant. We proved that the fracture mechanisms starts with the fracture of ferrite laths and ends with the fracture of austenite ligaments. We determined by quantitative metallography the average void nucleation rate and the spatial distribution of voids. This information, incorporated to the Gurson-Tvergaard-Joly model of a damaged elastoplastic material, served to predict adequately the distribution of the mean strain at fracture of notched axisymmetric specimens. The model also predicted the lower bound of the experimental distribution of the crack resistance at 0.2 mm of crack extension (J 02 ). (author)

  11. Temperature conditions in an LMFBR power plant from primary sodium to steam circuits

    International Nuclear Information System (INIS)

    Aubert, M.; Chaumont, J.M.; Mougniot, J.C.; Recolin, J.; Acket.

    1977-01-01

    The optimization analysis which is presented is based on an evaluation of the tender prior to contracting Super Phenix. Process constraints are reviewed: fuel limitations, turbine, steam generators; parameter selection involves major temperatures (primary ΔT 0 , steam generator water inlet temperature, turbine steam inlet temperature) or minor temperature (secondary sodium); countervailing mechanisms include upward and downward tendencies. The optimum values obtained by the method represent a coherent balanced set of parameters. So, the most significant tendency revealed by an optimization of investment costs involves the advantages of a hot system with a steam temperature above 515 0 C, but the hot temperature range is very limited (3 0 C between the hot primary sodium temperature and the steam temperature) while the cold temperatures cover a much wide range. The tolerance range within which each critical temperature may be selected without exceeding a certain cost margin per KWh is given

  12. Analytical and sampling problems in primary coolant circuits of PWR-type reactors

    International Nuclear Information System (INIS)

    Illy, H.

    1980-10-01

    Details of recent analytical methods on the analysis and sampling of a PWR primary coolant are given in the order as follows: sampling and preparation; analysis of the gases dissolved in the water; monitoring of radiating substances; checking of boric acid concentration which controls the reactivity. The bibliography of this work and directions for its use are published in a separate report: KFKI-80-48 (1980). (author)

  13. Network model and short circuit program for the Kennedy Space Center electric power distribution system

    Science.gov (United States)

    1976-01-01

    Assumptions made and techniques used in modeling the power network to the 480 volt level are discussed. Basic computational techniques used in the short circuit program are described along with a flow diagram of the program and operational procedures. Procedures for incorporating network changes are included in this user's manual.

  14. Evaluation of fatigue crack growth in the primary circuit pipeline of a WWER 440/213c type nuclear power plant

    International Nuclear Information System (INIS)

    Samohyl, P.

    1993-07-01

    The fatigue damage of the primary circuit of WWER-440/213c reactors was evaluated proceeding from actual and design operating data of units 3 and 4 of the Bohunice V-2 nuclear power plant. A complex computation model was set up, encompassing the main circulation pipeline, pressurizer pipeline, emergency core aftercooling system pipeline, steam pipeline, and feedwater pipeline. The standardized STATIC code was applied to the stress analysis, and the FATLBB code was used to determine the crack increment for all operating states and primary circuit sections. The probability of fatigue failure of the pipelines was found to be low. (J.B.). 55 tabs., 3 figs., 9 refs

  15. Isotope distributions in primary heat transport and containment systems during a severe accident in CANDU type reactor

    International Nuclear Information System (INIS)

    Constantin, M.

    2005-01-01

    The paper is intended to analyse the distribution of the fission products (FPs) in CANDU Primary Heat Transport (PHT) and CANDU Containment Systems by using the ASTEC code. The complexity of the data required by ASTEC and the complexity both of CANDU PHT and Containment System were strong motivation to begin with a simplified model. The data related to the nodes' definitions, temperatures and pressure conditions were chosen as possible as real data from CANDU loss of coolant accident sequence (CATHENA code results). The source term of FPs introduced into the PHT was estimated by ORIGEN code. The FPs distribution in the nodes of the circuit and the FPs mass transfer per isotope and chemical species were obtained by using SOPHAEROS module. The distributions within the containment are obtained by the CPA module (thermalhydraulic calculations in the containment and FPs aerosol transport). The results consist of mass distributions in the nodes of the circuit and the transferred mass to the containment through the break for different species (FPs and chemical species) and mass distributions in the different parts of the containment and different hosts. (authors)

  16. Professionals' perception of circuits of care for hypertensive or diabetic patients between primary and secondary care.

    Science.gov (United States)

    Alonso-Moreno, Francisco Javier; Martell-Claros, Nieves; de la Figuera, Mariano; Escalada, Javier; Rodríguez, Marta; Orera, Luisa

    2016-01-01

    To determine the flow of care for patients with type 2 diabetes mellitus (T2DM) and hypertension between primary care (PC) and specialized care (SC) in clinical practice, and the criteria used for referral and follow-up within the Spanish National Health System (NHS). A descriptive, cross-sectional, multicenter study. A probability convenience sampling stratified by number of physicians participating in each Spanish autonomous community was performed. Nine hundred and ninety-nine physicians were surveyed, of whom 78.1% (n=780) were primary care physicians (PCPs), while 11.9% (n=119) and 10.0% (n=100) respectively were specialists in hypertension and diabetes. KEY MEASUREMENTS: was conducted using two self administered online surveys. A majority of PCPs (63.7% and 55.5%) and specialists (79.8% and 45.0%) reported the lack of a protocol to coordinate the primary and specialized settings for both hypertension and T2DM respectively. The most widely used method for communication between specialists was the referral sheet (94.6% in PC and 92.4% in SC). The main reasons for referral to a specialist were refractory hypertension (80.9%) and suspected secondary hypertension (75.6%) in hypertensive patients, and suspicion of a specific diabetes (71.9%) and pregnancy (71.7%) in T2DM patients. Although results showed some common characteristics between PCPs and specialists in disease management procedures, the main finding was a poor coordination between PC and SC. Copyright © 2015. Published by Elsevier España, S.L.U.

  17. Distribution of language-related Cntnap2 protein in neural circuits critical for vocal learning.

    Science.gov (United States)

    Condro, Michael C; White, Stephanie A

    2014-01-01

    Variants of the contactin associated protein-like 2 (Cntnap2) gene are risk factors for language-related disorders including autism spectrum disorder, specific language impairment, and stuttering. Songbirds are useful models for study of human speech disorders due to their shared capacity for vocal learning, which relies on similar cortico-basal ganglia circuitry and genetic factors. Here we investigate Cntnap2 protein expression in the brain of the zebra finch, a songbird species in which males, but not females, learn their courtship songs. We hypothesize that Cntnap2 has overlapping functions in vocal learning species, and expect to find protein expression in song-related areas of the zebra finch brain. We further expect that the distribution of this membrane-bound protein may not completely mirror its mRNA distribution due to the distinct subcellular localization of the two molecular species. We find that Cntnap2 protein is enriched in several song control regions relative to surrounding tissues, particularly within the adult male, but not female, robust nucleus of the arcopallium (RA), a cortical song control region analogous to human layer 5 primary motor cortex. The onset of this sexually dimorphic expression coincides with the onset of sensorimotor learning in developing males. Enrichment in male RA appears due to expression in projection neurons within the nucleus, as well as to additional expression in nerve terminals of cortical projections to RA from the lateral magnocellular nucleus of the nidopallium. Cntnap2 protein expression in zebra finch brain supports the hypothesis that this molecule affects neural connectivity critical for vocal learning across taxonomic classes. Copyright © 2013 Wiley Periodicals, Inc.

  18. Modeling of a Pouch Lithium Ion Battery Using a Distributed Parameter Equivalent Circuit for Internal Non-Uniformity Analysis

    Directory of Open Access Journals (Sweden)

    Dafen Chen

    2016-10-01

    Full Text Available A battery model that has the capability of analyzing the internal non-uniformity of local state variables, including the state of charge (SOC, temperature and current density, is proposed in this paper. The model is built using a set of distributed parameter equivalent circuits. In order to validate the accuracy of the model, a customized battery with embedded T-type thermocouple sensors inside the battery is tested. The simulated temperature conforms well with the measured temperature at each test point, and the maximum difference is less than 1 °C. Then, the model is applied to analyze the evolution processes of local state variables’ distribution inside the battery during the discharge process. The simulation results demonstrate drastic distribution changes of the local state variables inside the battery during the discharge process. The internal non-uniformity is originally caused by the resistance of positive and negative foils, while also influenced by the change rate of open circuit voltage and the total resistance of the battery. Hence, the factors that affect the distribution of the local state variables are addressed.

  19. Inflammatory Cell Distribution in Primary Merkel Cell Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Wheat, Rachel [School of Cancer Sciences and CR UK Centre for Cancer Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT (United Kingdom); Roberts, Claudia [School of Cancer Sciences and CR UK Centre for Cancer Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT (United Kingdom); University Hospitals Birmingham NHS Foundation Trust, New Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Edgbaston, Birmingham, B15 2WB (United Kingdom); Waterboer, Tim [Infection and Cancer Program, DKFZ (German Cancer Research Centre), 69120 Heidelberg (Germany); Steele, Jane [Human Biomaterials Resource Centre, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT (United Kingdom); Marsden, Jerry [University Hospitals Birmingham NHS Foundation Trust, New Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Edgbaston, Birmingham, B15 2WB (United Kingdom); Steven, Neil M., E-mail: n.m.steven@bham.ac.uk [School of Cancer Sciences and CR UK Centre for Cancer Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT (United Kingdom); University Hospitals Birmingham NHS Foundation Trust, New Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Edgbaston, Birmingham, B15 2WB (United Kingdom); Blackbourn, David J., E-mail: n.m.steven@bham.ac.uk [Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH (United Kingdom)

    2014-05-06

    Merkel cell carcinoma (MCC) is an aggressive poorly differentiated neuroendocrine cutaneous carcinoma associated with older age, immunodeficiency and Merkel cell polyomavirus (MCPyV) integrated within malignant cells. The presence of intra-tumoural CD8+ lymphocytes reportedly predicts better MCC-specific survival. In this study, the distribution of inflammatory cells and properties of CD8+ T lymphocytes within 20 primary MCC specimens were characterised using immunohistochemistry and multicolour immunofluorescent staining coupled to confocal microscopy. CD8+ cells and CD68+ macrophages were identified in 19/20 primary MCC. CD20+ B cells were present in 5/10, CD4+ cells in 10/10 and FoxP3+ cells in 7/10 specimens. Only two specimens had almost no inflammatory cells. Within specimens, inflammatory cells followed the same patchy distribution, focused at the edge of sheets and nodules and, in some cases, more intense in trabecular areas. CD8+ cells were outside vessels on the edge of tumour. Those few within malignant sheets typically lined up in fine septa not contacting MCC cells expressing MCPyV large T antigen. The homeostatic chemokine CXCL12 was expressed outside malignant nodules whereas its receptor CXCR4 was identified within tumour but not on CD8+ cells. CD8+ cells lacked CXCR3 and granzyme B expression irrespective of location within stroma versus malignant nodules or of the intensity of the intra-tumoural infiltrate. In summary, diverse inflammatory cells were organised around the margin of malignant deposits suggesting response to aberrant signaling, but were unable to penetrate the tumour microenvironment itself to enable an immune response against malignant cells or their polyomavirus.

  20. Inflammatory Cell Distribution in Primary Merkel Cell Carcinoma

    International Nuclear Information System (INIS)

    Wheat, Rachel; Roberts, Claudia; Waterboer, Tim; Steele, Jane; Marsden, Jerry; Steven, Neil M.; Blackbourn, David J.

    2014-01-01

    Merkel cell carcinoma (MCC) is an aggressive poorly differentiated neuroendocrine cutaneous carcinoma associated with older age, immunodeficiency and Merkel cell polyomavirus (MCPyV) integrated within malignant cells. The presence of intra-tumoural CD8+ lymphocytes reportedly predicts better MCC-specific survival. In this study, the distribution of inflammatory cells and properties of CD8+ T lymphocytes within 20 primary MCC specimens were characterised using immunohistochemistry and multicolour immunofluorescent staining coupled to confocal microscopy. CD8+ cells and CD68+ macrophages were identified in 19/20 primary MCC. CD20+ B cells were present in 5/10, CD4+ cells in 10/10 and FoxP3+ cells in 7/10 specimens. Only two specimens had almost no inflammatory cells. Within specimens, inflammatory cells followed the same patchy distribution, focused at the edge of sheets and nodules and, in some cases, more intense in trabecular areas. CD8+ cells were outside vessels on the edge of tumour. Those few within malignant sheets typically lined up in fine septa not contacting MCC cells expressing MCPyV large T antigen. The homeostatic chemokine CXCL12 was expressed outside malignant nodules whereas its receptor CXCR4 was identified within tumour but not on CD8+ cells. CD8+ cells lacked CXCR3 and granzyme B expression irrespective of location within stroma versus malignant nodules or of the intensity of the intra-tumoural infiltrate. In summary, diverse inflammatory cells were organised around the margin of malignant deposits suggesting response to aberrant signaling, but were unable to penetrate the tumour microenvironment itself to enable an immune response against malignant cells or their polyomavirus

  1. Eco-friendly preparation of large-sized graphene via short-circuit discharge of lithium primary battery.

    Science.gov (United States)

    Kang, Shaohong; Yu, Tao; Liu, Tingting; Guan, Shiyou

    2018-02-15

    We proposed a large-sized graphene preparation method by short-circuit discharge of the lithium-graphite primary battery for the first time. LiC x is obtained through lithium ions intercalation into graphite cathode in the above primary battery. Graphene was acquired by chemical reaction between LiC x and stripper agents with dispersion under sonication conditions. The gained graphene is characterized by Raman spectrum, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Atomic force microscope (AFM) and Scanning electron microscopy (SEM). The results indicate that the as-prepared graphene has a large size and few defects, and it is monolayer or less than three layers. The quality of graphene is significant improved compared to the reported electrochemical methods. The yield of graphene can reach 8.76% when the ratio of the H 2 O and NMP is 3:7. This method provides a potential solution for the recycling of waste lithium ion batteries. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Survey on structural material investigations for the primary circuit of the SNR 300

    International Nuclear Information System (INIS)

    Grosser, E.D.; Lorenz, H.

    1977-01-01

    The material programs described so far cover major Important areas of structural material behavior in the primary system of a sodium cooled reactor. The results demonstrate that a good base is available for the design and safe operation of sodium systems. For complementation purposes some further work is needed in certain areas: creep-fatigue interaction mechanism and description of base material and weld metal behavior for design purposes, irradiation effects in the low-dose range on time-dependent material behavior, impact of heat-to-heat variation on materials properties data, establishment of a profound data base to evaluate sodium impact on mechanical properties, application of the leak-before-break concept in plant design, confirmation of laboratory test results by the operational experience of sodium cooled reactor systems. (author)

  3. Considerations in providing purification flows for 500 MWe PHWR primary circuits

    International Nuclear Information System (INIS)

    Sharma, A.K.; Goswami, S.; Bapat, C.N.; Sharma, V.K.

    1995-01-01

    The purpose of the purification system is to keep the primary heat transport (PHT) system clean by removing traces of impurities arising due to corrosion of the carbon steel pipes and heat transfer surfaces and erosion/corrosion of valve trims, pipes and mechanical seals or due to presence of soluble or insoluble fission products. These impurities are undesirable because they are usually radioactive, either naturally or through activation by the neutron flux as they are carried by the coolant through the reactor core. The purification system minimizes the probability of generation of radioactive impurities by controlling the chemistry of PHT coolant so that corrosion is minimum. Various considerations for providing the requisite purification flow to fulfill the above functions for a typical 500 MWe PHWR are presented. (author). 4 refs., 2 tabs., 2 figs

  4. Common-signal-induced synchronization in photonic integrated circuits and its application to secure key distribution.

    Science.gov (United States)

    Sasaki, Takuma; Kakesu, Izumi; Mitsui, Yusuke; Rontani, Damien; Uchida, Atsushi; Sunada, Satoshi; Yoshimura, Kazuyuki; Inubushi, Masanobu

    2017-10-16

    We experimentally achieve common-signal-induced synchronization in two photonic integrated circuits with short external cavities driven by a constant-amplitude random-phase light. The degree of synchronization can be controlled by changing the optical feedback phase of the two photonic integrated circuits. The change in the optical feedback phase leads to a significant redistribution of the spectral energy of optical and RF spectra, which is a unique characteristic of PICs with the short external cavity. The matching of the RF and optical spectra is necessary to achieve synchronization between the two PICs, and stable synchronization can be obtained over an hour in the presence of optical feedback. We succeed in generating information-theoretic secure keys and achieving the final key generation rate of 184 kb/s using the PICs.

  5. The use of the acoustic emission for the components of the primary circuit of the nuclear power plants

    International Nuclear Information System (INIS)

    Svoboda, V.

    1992-01-01

    Full text: The Modrany Engineering Works (Modranske strojirny) is a producer and a final supplier of the main connecting piping circuit systems and valves for the nuclear power plants (type VVER 440 and VVER 1000) built in Czechoslovakia. Besides the delivery and assembly of valves and components methods there were developed for a monitoring of the stated equipment ability of a service in the Material and Diagnostic Laboratory, which is a part of the company. An important object of this work is to obtain a sufficient set of data and to work out suitable methods, on the basis of which it would be possible to perform a serious estimation of residual service life of the main piping components after certain service operation of the nuclear power plant. During the operation of a nuclear power station a failure of the main piping circuit could happen in either of two possible modes: 1.) A sudden break - by an unstable defect propagation leading to a. final fracture of the piping; 2) A fatigue failure - which is characterised by a gradual subcritical growth of defect in relation to the loading parameters. This process is frequently accelerated by further processes, e.g. corrosion. It is therefore suitable to use such physical and mechanical quantities, which characterize the material damage. Acoustic emission signals belongs to these quantities. A knowledge of the response of these signals in relation to the damage of the material gives us the possibility to evaluate the residual life of the piping containing defects. The importance of this is increasing mainly after a long period of service. She paper deals in details with experience gained in application of acoustic emission, during pressure tests of primary circuit components (elbow, welds, T- junction etc) in laboratory conditions which imitate those in service. There are shown some results of cyclic fatigue tests by internal pressure on prototypes models and specimen. Acoustic emission method represents the

  6. Password Based Distribution Panel and Circuit Breaker Operation for the Safety of Lineman during Maintenance Work

    OpenAIRE

    Hudedmani, Mallikarjun G; Ummannanavar, Nitin; Mudaliar, Mani Dheeraj; Sooji, Chandana; Bogar, Mala

    2017-01-01

    Security is the prime concern in our day to day life while performing any activity. In the current scenario, accidental death of lineman is often read and evidenced. In this direction, a safety measure to safe guard the operator is found very necessary looking into the present working style. The electric lineman safety system is designed to control the control panel doors and circuit breaker by using a password for the safety. Critical electrical accidents to lineman are on the rise during el...

  7. Modelling of the local chemistry in stagnant areas in the PWR primary circuit

    International Nuclear Information System (INIS)

    Reid, Rick; Fruzzetti, Keith; Ahluwalia, Al; Summe, Alex; Dame, Cecile; Schmitt, Kyle

    2014-01-01

    MRP-236 demonstrated a correlation between stagnant or low flow conditions and stress corrosion cracking (SCC) of stainless steel components in the PWR primary system. Of the approximately 140 SCC events documented (affecting 15 different components), 83% involved stagnant or low flow conditions that were likely to be associated with chemical environments different from the well mixed bulk coolant. The chemistry in such locations is typically not monitored, and sampling is difficult or impossible. Actions to improve chemistry in regions of low or no coolant flow, such as flushing, cycling of components and imposition of more stringent make up water chemistry controls affect both operational costs and outage schedules. Similarly, design changes to improve flow in affected areas are costly or impracticable. Improving the understanding of the factors controlling chemistry in such areas and development of the capability to predict typical and worst case conditions will allow an informed assessment of procedural actions and/or design changes to improve local chemistry and thereby reduce SCC susceptibility. A project was undertaken to develop a model to predict local chemistry conditions in stagnant locations. The model comprises the iterative application of the EPRI MULTEQ solution chemistry equilibrium code and standard thermodynamic relationships to predict local chemistry conditions considered likely to have been present at the surfaces of components when SCC was initiated. The starting chemistry conditions are based on PWR primary system chemistry from different plant maneuvers (e.g., startup and shutdown conditions). The model was applied to three example components where SCC has occurred in the field. The selected components were: control rod drive mechanism canopy seals; valve drain lines; and reactor vessel o-ring leak-off lines. This paper provides a summary of the model and predicted local chemistry conditions that develop for the three example component as a

  8. Stress and fatigue analyses of primary circuit components of NPP using FEM

    International Nuclear Information System (INIS)

    Gal, P.

    2015-01-01

    This poster is a short illustration of the numerical assessment of the VVER-440 reactor pressure vessel (RPV) main flange. RPV main flange consists in free flange, pressure ring, flange bolts, nut and nickel gasket. Operating temperature transient modes, like heat up regime can lead to serious tension in bolts. So temperature fields have to be calculated. The fatigue assessment of the main flange bolt requires the determination of the coefficient of stress concentrators in bolt thread. Stress concentrators can be computed through FEM or given by norms (PNAEG). The most significant value of fatigue usage factor is in the first thread connection between bolt and nut. A finite element method (FEM) is used for calculation stress and temperature distribution in the reactor flange. The reassessment was performed according Czech normative document NTD-A.S.I. and VERLIFE

  9. Performance evaluation of parallel electric field tunnel field-effect transistor by a distributed-element circuit model

    Science.gov (United States)

    Morita, Yukinori; Mori, Takahiro; Migita, Shinji; Mizubayashi, Wataru; Tanabe, Akihito; Fukuda, Koichi; Matsukawa, Takashi; Endo, Kazuhiko; O'uchi, Shin-ichi; Liu, Yongxun; Masahara, Meishoku; Ota, Hiroyuki

    2014-12-01

    The performance of parallel electric field tunnel field-effect transistors (TFETs), in which band-to-band tunneling (BTBT) was initiated in-line to the gate electric field was evaluated. The TFET was fabricated by inserting an epitaxially-grown parallel-plate tunnel capacitor between heavily doped source wells and gate insulators. Analysis using a distributed-element circuit model indicated there should be a limit of the drain current caused by the self-voltage-drop effect in the ultrathin channel layer.

  10. Effect of high-temperature filtration on impurity composition in the primary circuit coolant of power units with WWER-1000 reactors

    International Nuclear Information System (INIS)

    Efimov, A.A.; Moskvin, L.N.; Gusev, B.A.; Leont'ev, G.G.; Nekrest'yanov, S.N.

    1992-01-01

    The effects of high-temperature filtration on changes in dispersive, chemical, radioisotope and phase compositions of impurities in primary circuit coolant of NPP with the WWER-1000 reactor are studied. Special filters are used for the studies. The data obtained confirm the applicability of high-temperature filtration for purification of WWER reactor water and steam separators at NPPs with RBMK reactors

  11. General thermodynamic description of pollutants and preservatives in water at high temperature: application to primary and secondary circuits of power plants

    International Nuclear Information System (INIS)

    Alvarez, Jorge L.; Kukuljan, Juan A.; Gutkowski, Karin; Japas, Maria L.; Fernandez Prini, Roberto

    1999-01-01

    A formalism has been developed for the description of solubilities and other thermodynamic functions, based only on the Krichevskii function and properties of the pure solvent. This formalism is applied to pollutants of primary and secondary circuits nuclear power plants. (author)

  12. Safety Research Program for Light Water Reactors. Technical report 2: BMFT support project RS 0036 B. Reflooding experiments with regard to primary circuits (PKL) instrumentation of experimental setup

    International Nuclear Information System (INIS)

    Schweickert, H.; Mandl, R.

    The reflooding of the hot core of a PWR will be investigated in a model of the complete primary system. The demands that the instrumentation must meet as well as a description of the measurement methods used in the circuit are described. Data on the efficiency of the instruments, error estimates and constructive solutions to design problems are also given

  13. The primary circuit materials properties results analysis performed on archive material used in NPP V-1 and Kola NPP Units 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    Kupca, L.; Beno, P. [Nuclear Power Plants Research Institute Inc., Trnava (Slovakia)

    1997-04-01

    A very brief summary is provided of a primary circuit piping material properties analysis. The analysis was performed for the Bohunice V-1 reactor and the Kola-1 and -2 reactors. Assessment was performed on Bohunice V-1 archive materials and primary piping material cut from the Kola units after 100,000 hours of operation. Main research program tasks included analysis of mechanical properties, corrosion stability, and microstructural properties. Analysis results are not provided.

  14. Transient short-circuit behaviour of distributed energy sources and their influence on protection coordination conference

    NARCIS (Netherlands)

    Geldtmeijer, D.A.M.; Provoost, F.; Myrzik, J.M.A.; Kling, W.L.

    2006-01-01

    This paper presents the results obtained by research on the influence of distributed generation (DG) on protection in the distribution network. Generation connected to the grid is subject to protection regulations. Applying the present regulations to distributed generation results in unnecessary

  15. Preparation of Power Distribution System for High Penetration of Renewable Energy Part I. Dynamic Voltage Restorer for Voltage Regulation Pat II. Distribution Circuit Modeling and Validation

    Science.gov (United States)

    Khoshkbar Sadigh, Arash

    by simulation and experimental tests under various conditions considering all possible cases such as different amounts of voltage sag depth (VSD), different amounts of point-on-wave (POW) at which voltage sag occurs, harmonic distortion, line frequency variation, and phase jump (PJ). Furthermore, the ripple amount of fundamental voltage amplitude calculated by the proposed method and its error is analyzed considering the line frequency variation together with harmonic distortion. The best and worst detection time of proposed method were measured 1ms and 8.8ms, respectively. Finally, the proposed method has been compared with other voltage sag detection methods available in literature. Part 2: Power System Modeling for Renewable Energy Integration: As power distribution systems are evolving into more complex networks, electrical engineers have to rely on software tools to perform circuit analysis. There are dozens of powerful software tools available in the market to perform the power system studies. Although their main functions are similar, there are differences in features and formatting structures to suit specific applications. This creates challenges for transferring power system circuit models data (PSCMD) between different software and rebuilding the same circuit in the second software environment. The objective of this part of thesis is to develop a Unified Platform (UP) to facilitate transferring PSCMD among different software packages and relieve the challenges of the circuit model conversion process. UP uses a commonly available spreadsheet file with a defined format, for any home software to write data to and for any destination software to read data from, via a script-based application called PSCMD transfer application. The main considerations in developing the UP are to minimize manual intervention and import a one-line diagram into the destination software or export it from the source software, with all details to allow load flow, short circuit and

  16. Mercury distribution characteristics in primary manganese smelting plants.

    Science.gov (United States)

    Back, Seung-Ki; Sung, Jin-Ho; Moon, Young-Hoon; Kim, Young-Hee; Seok, Kwang-Seol; Song, Geum-Ju; Seo, Yong-Chil

    2017-08-01

    The mercury (Hg) distribution characteristics were investigated in three primary manganese smelting plants in Korea for the assessment of anthropogenic Hg released. Input and output materials were sampled from each process, and Hg concentrations in the samples were analyzed. Among the input materials, the most mercury was found in the manganese ore (83.1-99.7%) and mercury was mainly released through fly ash or off gas, depending on the condition of off gas cleaning system. As off gas temperature decreases, proportion and concentration of emitted gaseous elemental mercury (Hg 0 ) in off gas decreases. Based on mass balance study from these three plants and national manganese production data, the total amount of mercury released from those Korean plants was estimated to 644 kg/yr. About half of it was emitted into the air while the rest was released to waste as fly ash. With the results of this investigation, national inventory for Hg emission and release could be updated for the response to Minamata Convention on Mercury. Copyright © 2017. Published by Elsevier Ltd.

  17. Reliability of an HTR-module primary circuit pressure boundary. Influences, sensitivity, and comparison with a PWR

    International Nuclear Information System (INIS)

    Staat, M.

    1995-01-01

    The reliability of the HTR-module for electricity and steam generation was analysed for normal operation, as well as accident conditions. The probabilistic fracture mechanics assessment was performed with a modification of the ZERBERUS code on the basis of widely used data. The calculated failure probabilities may thus be compared with similar investigations. The HTR-module primary circuit pressure boundary as a unit showed leak-before-break behaviour in a probabilistic sense, although a break was more probable than a leak for some of its parts.However, the findings may depend greatly on the stochastic data. Therefore a stochastic reference problem is defined and the results are compared with the Japanese round robin on a PWR section. Possible changes of failure probabilities and of the leak-before-break behaviour are discussed for different criteria for the events leading to a leak, and for modifications of the stochastic reference problem such as the inclusion of NDE. The results may be used to identify those stochastic variables which have the greatest influence on the computed failure probabilities, and to perhaps justify further work which would provide more detailed information on these probabilities. Furthermore, there is an obvious need for reduction of the non-statistical reasons for great variations of failure probabilities. (orig.)

  18. Simulation of the occupational radiation dose caused by contamination of primary circuit media in pressurized water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Artmann, Andreas; Bruhn, Gerd; Schneider, Sebastian [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Koeln (Germany); Strub, Erik [Koeln Univ. (Germany). Abt. Nuklearchemie

    2016-11-15

    The occupational radiation exposure of workers in NPPs during overall maintenance and refueling inspections and decommissioning is determined by numerous parameters. Radiation exposure caused by contamination of components may be minimised by the chemical operation mode and by applying systematic decontamination techniques. Data on occupational exposure in German NPPs as well as information about the radionuclide concentration in the coolant are available. The generic 3D model of the primary circuit presented is based on the analysis of technical documentation of German PWRs. Tasks are modeled as a combination of retention times at related local positions in the surroundings of work areas. The generic model allows the calculation of the resulting occupational doses generated by definable jobs and tasks. The KWU/Siemens- PWR generations are characterised by nuclide vectors, the thickness of shielding, and the material composition of components. It was possible to show that for a pre-Konvoi plant, the calculated occupational dose caused by a specific working task is close to measurements.

  19. Simulation of the occupational radiation dose caused by contamination of primary circuit media in pressurized water reactors

    International Nuclear Information System (INIS)

    Artmann, Andreas; Bruhn, Gerd; Schneider, Sebastian; Strub, Erik

    2016-01-01

    The occupational radiation exposure of workers in NPPs during overall maintenance and refueling inspections and decommissioning is determined by numerous parameters. Radiation exposure caused by contamination of components may be minimised by the chemical operation mode and by applying systematic decontamination techniques. Data on occupational exposure in German NPPs as well as information about the radionuclide concentration in the coolant are available. The generic 3D model of the primary circuit presented is based on the analysis of technical documentation of German PWRs. Tasks are modeled as a combination of retention times at related local positions in the surroundings of work areas. The generic model allows the calculation of the resulting occupational doses generated by definable jobs and tasks. The KWU/Siemens- PWR generations are characterised by nuclide vectors, the thickness of shielding, and the material composition of components. It was possible to show that for a pre-Konvoi plant, the calculated occupational dose caused by a specific working task is close to measurements.

  20. Effects of PbO on the oxide films of incoloy 800HT in simulated primary circuit of PWR

    International Nuclear Information System (INIS)

    Tan, Yu; Yang, Junhan; Wang, Wanwan; Shi, Rongxue; Liang, Kexin; Zhang, Shenghan

    2016-01-01

    Effects of trace PbO on oxide films of Incoloy 800HT were investigated in simulated primary circuit water chemistry of PWR, also with proper Co addition. The trace PbO addition in high temperature water blocked the protective spinel oxides formation of the oxide films of Incoloy 800HT. XPS results indicated that the lead, added as PbO into the high temperature water, shows not only +2 valance but also +4 and 0 valances in the oxide film of 800HT co-operated with Fe, Cr and Ni to form oxides films. Potentiodynamic polarization results indicated that as PbO concentration increased, the current densities of the less protective oxide films of Incoloy 800HT decreased in a buffer solution tested at room temperature. The capacitance results indicated that the donor densities of oxidation film of Incoloy 800HT decreased as trace PbO addition into the high temperature water. - Highlights: • Trace PbO addition into the high temperature water block the formation of spinel oxides on Incoloy 800HT. • The donor density of oxide film decreases with trace PbO addition. • The current density of potentiodynamic polarization decreases of oxide film with trace PbO addition.

  1. Impact of load follow operation on the chemistry of the primary and secondary circuit of a pressurized water reactor

    International Nuclear Information System (INIS)

    Boettcher, F.; Riehm, S.; Bolz, M.; Speck, A.

    2012-09-01

    Germany decided to abandon nuclear energy and to switch to renewable energy forms. According the renewable energy act renewable energy forms have priority to be fed to the grid. The support of wind and solar energy demands more and more load follow operation of the remaining nuclear power plants to stabilize the grid. This report summarizes first experience with load follow operation in two pressurized water reactors (Philippsburg KKP2 and Neckarwestheim GKNI) with regard to chemistry and radiology. The most important mechanisms of dose rate built up on the primary side are described with Co-60 and Co-58 being the main contributors to dose rate. Goal of the primary side chemistry is to avoid or at least to delay the dose rate built-up as far as achievable. Both reactors are operated according to the modified coordinated B-Li-Chemistry with a pH300 of 7.4 as target value for optimised dose build up delay. By using B-10-enriched boric acid with a boron-10 abundance of 30 at-% (compared to ca. 19.9 at-% in natural boron) the pH 300 target value can be reached earlier in the cycle due to the lower concentration of boric acid required for neutron balancing. In GKNI Zn-injection was started 2005 as a mean of dose reduction. Since 2007 GKNI was operated with load follow operation. In KKP2 load reductions due to wind energy excess are more and more common since 2008. The results of dose rate measurements on the primary side are correlated to primary coolant chemistry and load follow operation. The use of enriched boric acid had a positive (i.e. reducing dose rate) impact on the activity build-up of Co-60 on the loop lines, thus proving the effectiveness of the VGB specifications. After 5 years (one half life time of Co-60) of Zn-injection a positive effect on surface occupancy with nuclides can be determined. The impact of short term deviations from optimal chemical conditions during load follow operation on the activity build up is assessed on the basis of the corrosion

  2. Contribution to the study of the distribution of air within the lung using xenon 133 during primary bronchial carcinoma

    International Nuclear Information System (INIS)

    Laval, P.; Vigne, J.; Feliciano, J.M.; Kleisbauer, J.P.; Poirier, R.; Lins, M.I.

    1975-01-01

    An Anger gamma-camera coupled with a two route integrator to record graphs giving the activity of each lung, and a computer with two analog-digital converters for storage of data on paper and magnetic tape, were used. 133 Xe is inhaled in a closed circuit, then a radioactive bolus is given intravenously and expired. The present programme includes a count for each lung, the percentage of ventilation between the right and left lung, the percentage of aerial distribution of the 9 different areas for each lung compared with the whole of the side under consideration, restoration of the distribution curves on inspiration and wash-out on expiration for each of these zones. Study of 14 patients with primary bronchial carcinoma is made. The results are analyzed, typical cases are given, and the future prospects of the method, which may suggest a physical model reproducing the respiratory apparatus of a given subject, are discussed [fr

  3. Distributed Leadership: Key to Improving Primary Students' Mathematical Knowledge

    Science.gov (United States)

    Larson, Matthew R.; Smith, Wendy M.

    2013-01-01

    The purpose of this article is to present the findings of a quantitative study focused on primary mathematics teachers who participated in an intensive professional development program and then had leadership responsibility for the implementation of a new primary mathematics curriculum in their district. The study examines the effect of the…

  4. Sparse distributed representation of odors in a large-scale olfactory bulb circuit.

    Directory of Open Access Journals (Sweden)

    Yuguo Yu

    Full Text Available In the olfactory bulb, lateral inhibition mediated by granule cells has been suggested to modulate the timing of mitral cell firing, thereby shaping the representation of input odorants. Current experimental techniques, however, do not enable a clear study of how the mitral-granule cell network sculpts odor inputs to represent odor information spatially and temporally. To address this critical step in the neural basis of odor recognition, we built a biophysical network model of mitral and granule cells, corresponding to 1/100th of the real system in the rat, and used direct experimental imaging data of glomeruli activated by various odors. The model allows the systematic investigation and generation of testable hypotheses of the functional mechanisms underlying odor representation in the olfactory bulb circuit. Specifically, we demonstrate that lateral inhibition emerges within the olfactory bulb network through recurrent dendrodendritic synapses when constrained by a range of balanced excitatory and inhibitory conductances. We find that the spatio-temporal dynamics of lateral inhibition plays a critical role in building the glomerular-related cell clusters observed in experiments, through the modulation of synaptic weights during odor training. Lateral inhibition also mediates the development of sparse and synchronized spiking patterns of mitral cells related to odor inputs within the network, with the frequency of these synchronized spiking patterns also modulated by the sniff cycle.

  5. Verification results of methodology for determining the weighted mean coolant temperature in the primary circuit hot legs of WWER-1000 reactor plants

    Energy Technology Data Exchange (ETDEWEB)

    Saunin, Yuri V.; Dobrotvorski, Alexander N.; Semenikhin, Alexander V.; Korolev, Alexander S. [JSC ' ' Atomtechenergo' ' , Novovoronezh (Russian Federation). Novovoronezh Filial ' ' Novovoronezhatomtechenergo' ' ; Ryasny, Sergei I. [JSC ' ' Atomtechenergo' ' , Moscow (Russian Federation)

    2017-09-15

    The JSC ''Atomtechenergo'' experts have developed a new methodology for determining the weighted mean coolant temperature in the primary circuit hot legs of WWER-1000 reactor plants. The necessity for developing the new methodology was determined by the need to decrease the calculation error of the weighted mean coolant temperature in the hot legs because of the coolant temperature stratification. The methodology development was based on the findings of experimental and calculating research executed by the authors. The methodology verification was fulfilled through comparison of calculation results obtained with and without the methodology use in various operational states and modes of several WWER-1000 power units. The obtained verification results have confirmed that the use of the new methodology provides objective error decrease in determining the weighted mean coolant temperature in the primary circuit hot legs. The decrease value depends on the stratification character which is various for different objects and conditions.

  6. Verification results of methodology for determining the weighted mean coolant temperature in the primary circuit hot legs of WWER-1000 reactor plants

    International Nuclear Information System (INIS)

    Saunin, Yuri V.; Dobrotvorski, Alexander N.; Semenikhin, Alexander V.; Korolev, Alexander S.

    2017-01-01

    The JSC ''Atomtechenergo'' experts have developed a new methodology for determining the weighted mean coolant temperature in the primary circuit hot legs of WWER-1000 reactor plants. The necessity for developing the new methodology was determined by the need to decrease the calculation error of the weighted mean coolant temperature in the hot legs because of the coolant temperature stratification. The methodology development was based on the findings of experimental and calculating research executed by the authors. The methodology verification was fulfilled through comparison of calculation results obtained with and without the methodology use in various operational states and modes of several WWER-1000 power units. The obtained verification results have confirmed that the use of the new methodology provides objective error decrease in determining the weighted mean coolant temperature in the primary circuit hot legs. The decrease value depends on the stratification character which is various for different objects and conditions.

  7. Thermal hydraulic analyses of accidents associated with coolant leak from the primary circuit through a hole 10 mm equivalent diameter for the needs of PTS

    International Nuclear Information System (INIS)

    Krhounkova, J.; Kral, P.; Parduba, Z.

    1999-10-01

    The conservative assumptions of the analyses were oriented towards a worsening of the process with respect to the pressurized thermal shock (PTS). Four variants were treated, viz. leaks from the cold or hot leg, each at the rated power or zero power. Since the temperature of water supplied to the primary circuit by the emergency core cooling system is an important parameter with respect to a PTS, the calculations were performed by the iterative procedure: the basic thermal hydraulic calculation was performed by the RELAP5/MOD3.2.1 code which calculates the behaviour of the primary and secondary circuits, whereas the MELCOR code was used to calculate the behaviour of the parameters in the hermetic rooms. The calculation by the RELAP code was then repeated using data from the MELCOR calculations. Interventions by the reactor operators were also considered. (P.A.)

  8. Current distribution in LV networks during 1-phase MV short-circuit

    NARCIS (Netherlands)

    Waes, van J.B.M.; Provoost, F.; Merwe, van der J.; Cobben, J.F.G.; Deursen, van A.P.J.; van Riet, M.J.M.; Laan, van der P.C.T.

    2000-01-01

    This paper describes the consequences of a fault in a medium voltage network on the grounding systems at the LV-side. To study the current distribution and to verify the models, we deliberately introduced one phase to ground faults in the 10 kV floating MV network. The selected site was the end of a

  9. Short circuit behavior of distribution grids with a large share of distributied generation units

    NARCIS (Netherlands)

    Coster, E.J.; Karaliolios, P.; Xyngi, I.; Slootweg, J.G.; Popov, M.; Kling, W.L.; Sluis, van der L.

    2011-01-01

    increasing rapidly. Most of these units are connected to the distribution grid. With the increasing penetration level the impact of these units on for instance power flows, fault levels and protective systems cannot be neglected anymore. To allow an increasing penetration level of DG without causing

  10. To the application of TV and optical equipment for in-service inspection of reactor vessel and primary circuit component materials

    International Nuclear Information System (INIS)

    Afonin, Eh.M.; Bachelis, I.M.; Tokarev, E.A.; Yastrebov, V.E.

    1985-01-01

    Some problems of application of TV and optical equipment for inspection of reactor vessel and primary circuit component materials are considered taking the most widespread WWER-440 type reactor as an example. The most advanrageous objects of the inspection and typical zones of equipment arrangement are shown. Methods and peculiarities of the inspection with the use of TV and optical equipment are presented. Recommendations on rational application of the equipment for the inspection of WWER-440 reactor vessel components are given

  11. Part of the hydrogen in the intergranular crack by stress corrosion in primary circuit for the 600 and 690 nickel base alloys

    International Nuclear Information System (INIS)

    Odemer, G.; Coudurier, A.; Jambon, F.; Chene, J.; Odemer, G.; Coudurier, A.; Chene, J.

    2007-01-01

    The aim of this study is, in a first part, to characterize the hydrogen embrittlement sensitivity of the 600 and 690 based alloys in order to better understand the hydrogen role in the stress corrosion mechanism which appears in theses alloys in the primary circuit of the PWR type reactors. The authors studies how the hydrogen embrittlement is resulting from an interaction between the hydrogen and the plastic deformation. (A.L.B.)

  12. Automatic ultrasonic pre-service, and in-service inspection of pressurized components of the primary circuit of nuclear power stations

    International Nuclear Information System (INIS)

    Muller, G.P.; Hallermeier, L.; Heinrich, D.; Grabendorfer, W.; Rebrmann, M.

    1985-01-01

    Ultrasonic pre-service and especially in-service inspection activities on the primary circuit of nuclear power stations form an essential part of the maintenance work that must be performed throughout the lifetime to ensure plant integrity. Consequently, the equipment required to carry out these inspections must be continuously improved in respect of reliability, safety, accuracy and ease of handling in order to minimize disturbances and repairs and reduce radiation exposure of the personnel. The authors' discussion of technique, equipment and performance of automated ultrasonic inspection is based on 15 years of experience in the testing of components of the primary circuit in nuclear power stations. To cover all inspection areas of the RPV of a PWR, four different manipulators are required, two for the closure head, one for the studs and one for the cylindrical shell and bottom closure. The use of the newly developed equipment, which naturally meets all the recommendations of the licensing authorities, allows for the automatic inspection of the components of primary circuit of nuclear power stations and the thus helps to substantially decrease the radiation exposure of the personnel. All the manipulators and their control consoles were designed and manufactured by M.A.N., Nuremberg while the ultrasonic electronic system was developed by Krautkramer, Cologne

  13. The experimental definition of the acoustic standing wave series shapes, formed in the coolant of the primary circuit of VVER-440 type reactor

    International Nuclear Information System (INIS)

    Bulavin, V.V.; Pavelko, V.I.

    1995-01-01

    On the basis of pressure fluctuation measurements in some primary circuit loops at 2 nd Unit of Kola NPP with VVER-440 type reactors, the shapes of acoustic standing waves (ASW) were determined at frequencies corresponding to four minimal oscillation eigenfrequencies in the primary circuit coolant. On identification of the ASW modes and properties, experimental results based on six circulating loops in symmetric arrangement allowed determination of the three-dimensional space structure of the wave nodes and antinodes inside and outside of the reactor vessel (RV). As part of this analysis, the geometric features of the primary circuit that caused the formation of these standing waves were identified. Differences in each ASW shape were shown to cause different individual effects on the neutron field in the reactor core and on fuel assembly vibration. This has been partially confirmed by ex-core neutron ionization chamber noise analysis. One type of ASW, possessing an antinode inside the RV, can be used for measurement of the pressure coefficient of reactivity. However, this must be done with care to avoid the potential for incorrect results in some cases. The results presented in this paper can be readily extended to other VVER type reactors with both odd and even number of loops. (author)

  14. Components of the primary circuit of LWRs. Design, construction and calculation. Draft. Komponenten des Primaerkreises von Leichtwasserreaktoren. Auslegung, Konstruktion und Berechnung. Entwurf

    Energy Technology Data Exchange (ETDEWEB)

    1979-10-01

    This standard is to be applied to components made of metallic materials, operated at design temperatures of up to 673/sup 0/K (400/sup 0/C). The primary circuit as the pressure continement of the reactor coolant comprises: Reactor pressure vessel (without internals), steam generator (primary loop), pressurizer, reactor coolant pump housing, interconnecting pipings between the components mentioned above and appropriate various valve and instrument casings, pipings branding off from the above components and interconnecting pipings, including the appropriate instrument casings, up to and including the first isolating valve, pressure shielding of control rod drives.

  15. Teachers' reflections on distributive leadership in public primary ...

    African Journals Online (AJOL)

    hierarchy, leadership styles, power, principals, school climate, teacher ... of the work of the principal, has led to the emergence of distributive forms of ..... premised on shared collaboration, where their function is to “connect and contribute”.

  16. Distributed generation: An empirical analysis of primary motivators

    International Nuclear Information System (INIS)

    Carley, Sanya

    2009-01-01

    What was once an industry dominated by centralized fossil-fuel power plants, the electricity industry in the United States is now evolving into a more decentralized and deregulated entity. While the future scope and scale of the industry is not yet apparent, recent trends indicate that distributed generation electricity applications may play an important role in this transformation. This paper examines which types of utilities are more likely to adopt distributed generation systems and, additionally, which factors motivate decisions of adoption and system capacity size. Results of a standard two-part model reveal that private utilities are significantly more inclined to adopt distributed generation than cooperatives and other types of public utilities. We also find evidence that interconnection standards and renewable portfolio standards effectively encourage consumer-owned distributed generation, while market forces associated with greater market competition encourage utility-owned distributed generation. Net metering programs are also found to have a significant marginal effect on distributed generation adoption and deployment.

  17. Distributed generation: An empirical analysis of primary motivators

    Energy Technology Data Exchange (ETDEWEB)

    Carley, Sanya [Department of Public Policy and Center for Sustainable Energy, Environment, and Economic Development, University of North Carolina at Chapel Hill, CB3435, Chapel Hill, NC 27599 (United States)], E-mail: scarley@email.unc.edu

    2009-05-15

    What was once an industry dominated by centralized fossil-fuel power plants, the electricity industry in the United States is now evolving into a more decentralized and deregulated entity. While the future scope and scale of the industry is not yet apparent, recent trends indicate that distributed generation electricity applications may play an important role in this transformation. This paper examines which types of utilities are more likely to adopt distributed generation systems and, additionally, which factors motivate decisions of adoption and system capacity size. Results of a standard two-part model reveal that private utilities are significantly more inclined to adopt distributed generation than cooperatives and other types of public utilities. We also find evidence that interconnection standards and renewable portfolio standards effectively encourage consumer-owned distributed generation, while market forces associated with greater market competition encourage utility-owned distributed generation. Net metering programs are also found to have a significant marginal effect on distributed generation adoption and deployment.

  18. Distributed generation. An empirical analysis of primary motivators

    Energy Technology Data Exchange (ETDEWEB)

    Carley, Sanya [Department of Public Policy and Center for Sustainable Energy, Environment, and Economic Development, University of North Carolina at Chapel Hill, CB3435, Chapel Hill, NC 27599 (United States)

    2009-05-15

    What was once an industry dominated by centralized fossil-fuel power plants, the electricity industry in the United States is now evolving into a more decentralized and deregulated entity. While the future scope and scale of the industry is not yet apparent, recent trends indicate that distributed generation electricity applications may play an important role in this transformation. This paper examines which types of utilities are more likely to adopt distributed generation systems and, additionally, which factors motivate decisions of adoption and system capacity size. Results of a standard two-part model reveal that private utilities are significantly more inclined to adopt distributed generation than cooperatives and other types of public utilities. We also find evidence that interconnection standards and renewable portfolio standards effectively encourage consumer-owned distributed generation, while market forces associated with greater market competition encourage utility-owned distributed generation. Net metering programs are also found to have a significant marginal effect on distributed generation adoption and deployment. (author)

  19. Study of water radiolysis in relation with the primary cooling circuit of pressurized water reactors; Etude sur la radiolyse de l`eau en relation avec le circuit primaire de refroidissement des reacteurs nucleaires a eau sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Pastina, B

    1997-07-01

    This memorandum shows a fundamental study on the water radiolysis in relation with the cooling primary circuit of PWR type reactors. The water of the primary circuit contains boric acid a soluble neutronic poison and also hydrogen that has for role to inhibit the water decomposition under radiation effect. In the aim to better understand the mechanism of dissolved hydrogen action and to evaluate the impact of several parameters on this mechanism, aqueous solutions with boric acid and hydrogen have been irradiated in a experimental nuclear reactor, at 30, 100 and 200 Celsius degrees. It has been found that, with hydrogen, the water decomposition under irradiation is a threshold phenomenon in function of the ratio between the radiation flux `1` B(n, )`7 Li and the gamma flux. When this ratio become too high, the number of radicals is not sufficient to participate at the chain reaction, and then water is decomposed in O{sub 2} and H{sub 2}O{sub 2} in a irreversible way. The temperature has a beneficial part on this mechanism. The iron ion and the copper ion favour the water decomposition. (N.C.). 83 refs.

  20. Analysis of the kinetic behaviour of iodine and caesium isotopes in the primary circuit of LWR's during severe fuel damage accidents

    International Nuclear Information System (INIS)

    Alonso, A.; Fernandez, S.; Buron, J.M.; Lopez, J.V.

    1991-01-01

    This State of the Art report deals with the chemical behaviour of caesium and iodine in the primary system, focusing particularly on kinetic chemical aspects. In case of a postulated severe accident in a nuclear reactor, cesium and iodine fission products are among the major contributors to health harm because of their high volatility and radiotoxicity. The extent of the release of such fission products to the environment depends on the effectiveness of transport through different structures in the reactor coolant system and within the reactor building. The release from fuel has been briefly studied; only those aspects concerning to iodine and caesium chemical forms when released have been reviewed; nevertheless the emphasis has been put on the transport of such elements and their species through the primary system. Some thermochemical equilibrium studies, applied to primary circuit conditions in LWR's, have been analyzed. The revision of the few kinetic studies existing on this matter has shown that kinetic behaviour of iodine and caesium isotopes in the primary circuit is an aspect poorly studied, despite the fact that kinetic aspects could have great importance on the chemical species formed under certain conditions. Other phenomena affecting iodine and caesium transport, besides chemical reactions, such as interactions with surfaces, aerosols or other chemical species have also been examined from available information on diverse experiments

  1. Conceptions of Pupils of the Primary on the Topic of an Electric Circuit in Three Countries (Canada, France and Morocco)

    Science.gov (United States)

    Métioui, Abdeljalil; MacWillie, Mireille Baulu; Trudel, Louis

    2016-01-01

    Qualitative research conducted with 237 pupils from Canada, France, and Morocco, between 10 and 12 years of age, on the setting and functioning of simple electric circuits, demonstrates that similar explanatory systems of the students. For this, we had given them a paper and pencil questionnaire of a sixty minutes duration. The first question was…

  2. A Power Hardware-in-the-Loop Platform with Remote Distribution Circuit Cosimulation

    Energy Technology Data Exchange (ETDEWEB)

    Palmintier, Bryan; Lundstrom, Blake; Chakraborty, Sudipta; Williams, Tess L.; Schneider, Kevin P.; Chassin, David P.

    2015-04-01

    This paper demonstrates the use of a novel cosimulation architecture that integrates hardware testing using Power Hardware-in-the-Loop (PHIL) with larger-scale electric grid models using off-the-shelf, non-PHIL software tools. This architecture enables utilities to study the impacts of emerging energy technologies on their system and manufacturers to explore the interactions of new devices with existing and emerging devices on the power system, both without the need to convert existing grid models to a new platform or to conduct in-field trials. The paper describes an implementation of this architecture for testing two residential-scale advanced solar inverters at separate points of common coupling. The same hardware setup is tested with two different distribution feeders (IEEE 123 and 8500 node test systems) modeled using GridLAB-D. In addition to simplifying testing with multiple feeders, the architecture demonstrates additional flexibility with hardware testing in one location linked via the Internet to software modeling in a remote location. In testing, inverter current, real and reactive power, and PCC voltage are well captured by the co-simulation platform. Testing of the inverter advanced control features is currently somewhat limited by the software model time step (1 sec) and tested communication latency (24 msec). Overshoot induced oscillations are observed with volt/VAR control delays of 0 and 1.5 sec, while 3.4 sec and 5.5 sec delays produced little or no oscillation. These limitations could be overcome using faster modeling and communication within the same co-simulation architecture.

  3. The Challenges of Distributing Leadership in Irish Post-Primary Schools

    Science.gov (United States)

    O'Donovan, Margaret

    2015-01-01

    This study explores the challenges and opportunities in relation to developing distributed leadership practice in Irish post-primary schools. It considers school leadership within the context of contemporary distributed leadership theory. Associated concepts such as distributed cognition and activity theory are used to frame the study. The study…

  4. Professional learning for distributed leadership:Primary headteachers’ perspectives

    OpenAIRE

    Torrance, Deirdre

    2015-01-01

    This article draws from a small-scale study of headteachers motivated to positively impact on the quality of pupil experience by involving all staff in a distributed perspective on leadership. Each headteacher perceived leadership as involving learned processes requiring support and experience, expending considerable effort in providing a fertile environment for learning about its practice. This perspective developed from their personal experience of challenging established leadership orthodo...

  5. The computation of the build-up of long-lived radioisotopes on the surface of primary circuits and the ion exchange material of BWR

    International Nuclear Information System (INIS)

    Lundgren, K.

    1980-06-01

    The buildup of radionuclides on the surface of the primary circuits and in the ion exchange material is calculated. The computation is made by the computer code 'CRUD'. The buildup is interesting from the viewpoint of nuclear waste. Oskarshamn 2 is chosen as the reference plant. An extrapolation is made for 20 years of operation. Calculation are givin for Mn54, Fe55, Co60, Ni59, Ni63 and Zn65. The constants of deposition and disharge are determined by fitting the values. (G.B.)

  6. Oscillator circuits

    CERN Document Server

    Graf, Rudolf F

    1996-01-01

    This series of circuits provides designers with a quick source for oscillator circuits. Why waste time paging through huge encyclopedias when you can choose the topic you need and select any of the specialized circuits sorted by application?This book in the series has 250-300 practical, ready-to-use circuit designs, with schematics and brief explanations of circuit operation. The original source for each circuit is listed in an appendix, making it easy to obtain additional information.Ready-to-use circuits.Grouped by application for easy look-up.Circuit source listing

  7. Measuring circuits

    CERN Document Server

    Graf, Rudolf F

    1996-01-01

    This series of circuits provides designers with a quick source for measuring circuits. Why waste time paging through huge encyclopedias when you can choose the topic you need and select any of the specialized circuits sorted by application?This book in the series has 250-300 practical, ready-to-use circuit designs, with schematics and brief explanations of circuit operation. The original source for each circuit is listed in an appendix, making it easy to obtain additional information.Ready-to-use circuits.Grouped by application for easy look-up.Circuit source listings

  8. Distributed practice and retrieval practice in primary school vocabulary learning: A multi-classroom study

    NARCIS (Netherlands)

    Goossens, Nicole; Camp, Gino; Verkoeijen, Peter; Tabbers, Huib; Bouwmeester, Samantha; Zwaan, Rolf

    2018-01-01

    Distributed practice and retrieval practice are promising learning strategies to use in education. We examined the effects of these strategies in primary school vocabulary lessons. Grades 2, 3, 4, and 6 children performed exercises that were part of the regular curriculum. For the distributed

  9. Reverse osmosis and its use at the nuclear power plants. Purification of primary circuit coolant by the means of reverse osmosis

    International Nuclear Information System (INIS)

    Kus, Pavel; Vonkova, Katerina; Kunesova, Katerina; Bartova, Sarka; Skala, Martin; Moucha, Tomáš

    2014-01-01

    This contribution is focused on the use of membrane technologies (e.g. reverse osmosis) for the primary coolant purification at the nuclear power plants. Currently, boric acid present in the primary coolant is preconcentrated at the evaporators, but their operation is very inefficient and expensive. Therefore, reverse osmosis was proposed as one of promising methods possibly replacing evaporators. The aim of the purification process is to achieve boric acid solution of a defined concentration (40 g/l) in the retentate stream in order to recycle it and reuse it in the primary circuit. Additionally, permeate flow should consist solely of pure water. To study the efficiency of several reverse osmosis modulus in the boric acid removal form the water solutions, experimental apparatus was constructed in our laboratory. It consists of the solution reservoir, pump and reverse osmosis modulus. The arrangement of experiments was batch and the retentate flow was refluxed to the feed solution. Several modulus of commercial reverse osmosis membranes were tested. The feed solution contained various concentrations of H 3 BO 3 , KOH, LiOH and NH 3 in order to simulate real primary coolant composition. Based on the experimental results, mathematical model was developed in order to optimize experimental conditions for the best results in primary coolant purification and boric acid preconcentration. (author)

  10. Analysis of the impact of connecting a larger number of small hydroelectric power plants to the short-circuit currents values and relay protection system of distribution network

    Directory of Open Access Journals (Sweden)

    Sučević Nikola

    2017-01-01

    Full Text Available In this paper the influence of a large number of small hydro power plants on the short-circuit currents is analysed, as well as the operation of the relay protection system within the real distribution network in Serbia. The necessary modification of the existing protection functions, as well as the implementation of the new proposed protection functions, are presented and discussed. Network modeling and analysis are performed using the program tool DIgSILENT PowerFactory.

  11. The removal of gaseous impurities from the primary circuit in high temperature reactors with cerium-mischmetal-getters

    International Nuclear Information System (INIS)

    Heinen, R.

    1986-11-01

    The use of getters to remove tritium and other gaseous impurities (especially H 2 , N 2 and CO) from helium circuits in nuclear reactors has been investigated. The loading capcity of beds, containing small cerium-mischmetal chips has been tested for several typical conditions. The results show that it is possible to use getters to purify inert gas streams for given boundary conditions. High CO-levels, however, lead to a poisoning (passivation) of the getter material. The effect of poisoning is cumulative. A mathematical model describes the behavior of CO in this kind of getter. Safety tests under possible accident conditions were made with the highly reactive cerium-mischmetal chips. The results show that there isn't a critical problem in using this material in the form of a chemical reactive getter bed near a nuclear reactor in the investigated range of accident conditions. (orig.) [de

  12. Radioactivity of long-lived nuclides in the primary circuit of the reactor BOR-60 during operation with defective fuel elements

    International Nuclear Information System (INIS)

    Gryazev, V.M.; Kizin, V.D.; Lisitsyn, E.S.; Polyakov, V.I.; Chechetkin, Y.V.

    1978-06-01

    The summarized results of measurements of the enrichment and distribution of radioactive nuclides from corrosion and of fission products during the four years of operation of BOR-60, including a longer period of operation with detective fuel elements in the core, are presented. It is shown that for operation with approximately 1% leaking fuel rods radiation exposure becomes worse manily because of release and enrichment of cesium isotopes in the coolant. Of the other fission products, the largest contribution to the dose rate in pipework and components is given by 140 Ba / 140 La and 95 Nb. On operation with 0.1 to 0.2% of leaking fuel rods, this contribution is comparable to that of the corrosion products 60 Co and 54 Mn. The radioactivity of corrosion products in the circuit has not increased within the last three years and was about one order of magnitude lower than the theoretical values. The corrosion and fission products are nonuniformly distributed over the circuit. Concentration of 95 Nb and 60 Co in the pipe for 'cold' sodium is larger by a factor of 2 - 5 and of 140 Ba and 54 Mn by a factor of 10-20 than in the pipes for 'hot' sodium. Most of the cobalt was found to deposit in the heat exchanges. The effectiveness of emptying the pipes from coolant in order to reduce the dose sate is assessed. (orig.) [de

  13. Business opportunities and dynamic competition through distributed generation in primary electricity distribution networks

    International Nuclear Information System (INIS)

    Raineri, R.; Rios, S.; Vasquez, R.

    2005-01-01

    In this paper, for a real electricity distribution network, an assessment of business opportunities to invest in distributed generation (DG) is performed through a simulation based on a full representation of three medium voltage (12 kV) feeders. The three feeders representation includes 1062 sections of conductors with 13 different sizes. The economic assessment focuses on both, the incentives of the incumbent distribution company and those of a new entrant. The technical and economic impact on losses, reliability and voltage regulation in the network area are verified. The DG solution analyzed determines a business opportunity for new investors where end users are also benefited. This work calls in the debate on the need to reformulate the current regulation model on electricity distribution, by defining clear rules to incorporate DG to the existing network, and to enable any agent to develop the proposed business. DG success depends on the location of adequate sites to strategically establish few DG units being a substitute to network expansion

  14. Application of the Severe Accident Code ATHLET-CD. Coolant injection to primary circuit of a PWR by mobile pump system in case of SBLOCA severe accident scenario

    Energy Technology Data Exchange (ETDEWEB)

    Jobst, Matthias; Wilhelm, Polina; Kliem, Soeren; Kozmenkov, Yaroslav [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Reactor Safety

    2017-06-01

    The improvement of the safety of nuclear power plants is a continuously on-going process. The analysis of transients and accidents is an important research topic, which significantly contributes to safety enhancements of existing power plants. In case of an accident with multiple failures of safety systems, core uncovery and heat-up can occur. In order to prevent the accident to turn into a severe one or to mitigate the consequences of severe accidents, different accident management measures can be applied. By means of numerical analyses performed with the compute code ATHLET-CD, the effectiveness of coolant injection with a mobile pump system into the primary circuit of a PWR was studied. According to the analyses, such a system can stop the melt progression if it is activated prior to 10 % of total core is molten.

  15. Application of the Severe Accident Code ATHLET-CD. Coolant injection to primary circuit of a PWR by mobile pump system in case of SBLOCA severe accident scenario

    International Nuclear Information System (INIS)

    Jobst, Matthias; Wilhelm, Polina; Kliem, Soeren; Kozmenkov, Yaroslav

    2017-01-01

    The improvement of the safety of nuclear power plants is a continuously on-going process. The analysis of transients and accidents is an important research topic, which significantly contributes to safety enhancements of existing power plants. In case of an accident with multiple failures of safety systems, core uncovery and heat-up can occur. In order to prevent the accident to turn into a severe one or to mitigate the consequences of severe accidents, different accident management measures can be applied. By means of numerical analyses performed with the compute code ATHLET-CD, the effectiveness of coolant injection with a mobile pump system into the primary circuit of a PWR was studied. According to the analyses, such a system can stop the melt progression if it is activated prior to 10 % of total core is molten.

  16. Fracture toughness assessment of in-service aged primary circuit elbows using mini C(T) specimens taken from outer skin

    International Nuclear Information System (INIS)

    Jayet-Gendrot, S.; Meylogan, T.; Ould, P.

    1995-05-01

    Type CF8M cast duplex stainless steels used in the primary circuit elbows of pressurized water reactors are subject to thermal aging embrittlement at their service temperature, around 300 deg. C. This phenomenon affects their fracture toughness properties. In order to assess the residual fracture toughness of these elbows, estimations are made through predictive formulae based on chemical composition and aging conditions, which provide safe values. However, in the case of the most sensitive materials, it is important to obtain more accurate estimations. A new method of determination was thus considered, based on the testing of mini-CT specimens taken from the skin of in-service elbows. The feasibility of using mini-CT specimens to evaluate the tearing resistance of cast duplex stainless steels seems at first sight difficult, in particular because of the very coarse metallurgical structure of these steels: will small specimens be representative of larger volumes (mainly regular T-CT specimens) and will they not induce too much scatter ? In order to answer such questions, an experimental validation program has been undertaken: the completed program shows that the method is relevant and leads to proposed guidelines which aim at optimizing the experimental results analysis. Then the method is applied to an in-service elbow: the results obtained are found to be in good agreement with the toughness estimations given by our predictive formulae. This subsequently contributes to the validation of the general methodology used for the justification of French primary circuit elbows. (authors). 7 refs., 4 figs., 5 tabs

  17. The Italian primary school-size distribution and the city-size: a complex nexus

    Science.gov (United States)

    Belmonte, Alessandro; di Clemente, Riccardo; Buldyrev, Sergey V.

    2014-06-01

    We characterize the statistical law according to which Italian primary school-size distributes. We find that the school-size can be approximated by a log-normal distribution, with a fat lower tail that collects a large number of very small schools. The upper tail of the school-size distribution decreases exponentially and the growth rates are distributed with a Laplace PDF. These distributions are similar to those observed for firms and are consistent with a Bose-Einstein preferential attachment process. The body of the distribution features a bimodal shape suggesting some source of heterogeneity in the school organization that we uncover by an in-depth analysis of the relation between schools-size and city-size. We propose a novel cluster methodology and a new spatial interaction approach among schools which outline the variety of policies implemented in Italy. Different regional policies are also discussed shedding lights on the relation between policy and geographical features.

  18. Simulation program for the dynamic behaviour of the primary system and moderators's circuit of the Atucha I Nuclear Power Plant

    International Nuclear Information System (INIS)

    Castano, Jorge; Gvirtzman, H.A.

    1981-01-01

    A model of digital computation is presented to simulate the primary system of heat transportation, moderator system and the associated systems for adjustment, regulation and control in the PHWR reactor at the Atucha-1 nuclear power plant. The model discusses in a concentrated way the different components and allows the study of the dynamical behaviour of the power plant facing disturbances with respect to a state of stationary regime. General considerations and description of the model are made. The method is described showing flow sheets, graphs and developing basic formulas, simulating a primary system, moderator and secondary system of the steam generator and the main system of regulation. Also an analysis of the results is made, for the case of disturbances which reduce or increase the power of the reactor by 10%. (V.B.) [es

  19. Response characteristics of HPR1000 primary circuit under different working conditions of the atmospheric relief system after SBLOCA

    Energy Technology Data Exchange (ETDEWEB)

    Sui, Danting, E-mail: suidanting@163.com [School of Nuclear Science and Engineering, North China Electric Power University, Beijing (China); Beijing Key Laboratory of Passive Safety Technology for Nuclear Energy, North China Electric Power University, Beijing (China); Lu, Daogang [School of Nuclear Science and Engineering, North China Electric Power University, Beijing (China); Beijing Key Laboratory of Passive Safety Technology for Nuclear Energy, North China Electric Power University, Beijing (China); Shang, Changzhong; Wei, Yuanyuan [China Nuclear Power Design Co., ltd (ShenZhen), Shenzhen (China); Zhang, Xianjie [School of Nuclear Science and Engineering, North China Electric Power University, Beijing (China); Beijing Key Laboratory of Passive Safety Technology for Nuclear Energy, North China Electric Power University, Beijing (China)

    2017-04-01

    Highlights: • Response of HPR1000 under different VDA conditions after SBLOCA was investigated. • Activation of VDA can trigger ACCU SI earlier with a critical point exists. • VDA capability design should compromise the critical point with reactivity feedback. - Abstract: To cope with SBLOCA in absence of High-Head Safety Injection (HHSI) from design of HPR1000, atmospheric relief system (originally named as VDA in French) is uniquely designed to help to trigger Middle Head Safety Injection (MHSI) or Low Head Safety Injection (LHSI) earlier through cooling primary system quickly after SBLOCA. To make the best use of VDA decay heat removal capability, primary and secondary system of HPR1000 was modeled with RELAP5/SCDAP computer code. After steady-state initialization, a cold leg 30 mm break SBLOCA was simulated with six simulation conditions and five additional cases including availability of ACCU, different VDA discharge locations and area. Response characteristics of primary loop under different VDA working conditions are investigated. Pressurizer pressure decreases rapidly to lower level to trigger the reactor scram, VDA activation and accumulator safety injection sequently. Peak cladding temperature is 899.45 K occurring at 222 s, which is far below the safety limit. Activation of VDA can trigger ACCU SI earlier with a critical point, while positive reactivity will be introduced due to negative moderator temperature effect and Doppler effect. Larger VDA discharge capability will introduce larger reactivity feedback, as well as induce lower core level and SG level. It's suggested that VDA discharge condition should be chosen before the critical point, with the compromise with reactivity feedback introduced due to the negative moderator temperature effect.

  20. Stress corrosion cracking of iron-nickel-chromium alloys in primary circuit environment of PWR-type reactors

    International Nuclear Information System (INIS)

    Boursier, Jean-Marie

    1993-01-01

    Stress corrosion cracking of Alloy 600 steam generator tubing is a great concern for pressurized water reactors. The mechanism that controls intergranular stress corrosion cracking of Alloy 600 in primary water (lithiated-borated water) has yet to be clearly identified. A study of stress corrosion cracking behaviour, which can identify the main parameters that control the cracking phenomenon, was so necessary to understand the stress corrosion cracking process. Constant extension rate tests, and constant load tests have evidenced that Alloy 600 stress corrosion cracking involves firstly an initiation period, then a slow propagation stage with crack less than 50 to 80 micrometers, and finally a rapid propagation stage leading to failure. The influence of mechanical parameters have shown the next points: - superficial strain hardening and cold work have a strong effect of stress corrosion cracking resistance (decrease of initiation time and increase of crack growth rate), - strain rate was the most suitable parameter for describing the different stage of propagation. The creep behaviour of alloy 600 has shown an increase of creep rate in primary water compared to air, which implies a local interaction plasticity/corrosion. An assessment of the durations of the initiation and the propagation stages was attempted for the whole uniaxial tensile tests, using the macroscopic strain rate: - the initiation time is less than 100 hours and seems to be an electrochemical process, - the durations of the propagation stage are strongly dependent on the strain rate. The behaviour in high primary water temperature of Alloys 690 and 800, which replace Alloy 600, was studied to appraise their margin, and validate their choice. Then the last chapter has to objective to evaluate the crack tip strain rate, in order to better describe the evolution of the different stages of cracking. (author) [fr

  1. Response characteristics of HPR1000 primary circuit under different working conditions of the atmospheric relief system after SBLOCA

    International Nuclear Information System (INIS)

    Sui, Danting; Lu, Daogang; Shang, Changzhong; Wei, Yuanyuan; Zhang, Xianjie

    2017-01-01

    Highlights: • Response of HPR1000 under different VDA conditions after SBLOCA was investigated. • Activation of VDA can trigger ACCU SI earlier with a critical point exists. • VDA capability design should compromise the critical point with reactivity feedback. - Abstract: To cope with SBLOCA in absence of High-Head Safety Injection (HHSI) from design of HPR1000, atmospheric relief system (originally named as VDA in French) is uniquely designed to help to trigger Middle Head Safety Injection (MHSI) or Low Head Safety Injection (LHSI) earlier through cooling primary system quickly after SBLOCA. To make the best use of VDA decay heat removal capability, primary and secondary system of HPR1000 was modeled with RELAP5/SCDAP computer code. After steady-state initialization, a cold leg 30 mm break SBLOCA was simulated with six simulation conditions and five additional cases including availability of ACCU, different VDA discharge locations and area. Response characteristics of primary loop under different VDA working conditions are investigated. Pressurizer pressure decreases rapidly to lower level to trigger the reactor scram, VDA activation and accumulator safety injection sequently. Peak cladding temperature is 899.45 K occurring at 222 s, which is far below the safety limit. Activation of VDA can trigger ACCU SI earlier with a critical point, while positive reactivity will be introduced due to negative moderator temperature effect and Doppler effect. Larger VDA discharge capability will introduce larger reactivity feedback, as well as induce lower core level and SG level. It's suggested that VDA discharge condition should be chosen before the critical point, with the compromise with reactivity feedback introduced due to the negative moderator temperature effect.

  2. After-production and in-service inspections of components of nuclear power plant primary coolant circuits

    International Nuclear Information System (INIS)

    Slama, K.; Svetlik, M.

    1990-01-01

    A new diagnostic system was developed for detecting defects in the material of mechanically loaded equipment. It is based on the measurement of elastic strain waves propagating through the materials. The instrument units as well as the methodology and software are of Czechoslovak origin and can be modified to conform to the requirements and experience of the user. The way of applying the method to the diagnostics of pressure vessels, main circulation pumps of the pressurizers and of the primary piping is described. Some results of after-production and in-service acoustic emission tests are given, as are the technical parameters of the acoustic emission analyzer. (M.D.). 5 figs

  3. Teachers' reflections on distributive leadership in public primary schools in Soweto

    Directory of Open Access Journals (Sweden)

    Suraiya R Naicker

    2013-01-01

    Full Text Available Schooling has become increasingly complex in purpose and structure and therefore requires appropriate forms of leadership to address this challenge. One current leadership approach that is receiving national and global attention is distributive leadership. A qualitative approach was employed to investigate teachers' experiences and perceptions of the practice of distributive leadership in public primary schools in Soweto. Soweto is a township in Johannesburg, South Africa, which comprises predominantly black African residents. The findings revealed that leadership in Soweto primary schools is rooted in classical leadership practices and that any potential for the practice of distributive leadership is hindered by autocratic styles of leadership, hierarchical structures, and non-participative decision-making.

  4. Method for evaluating the system instrumentation for loose part detection in the primary cooling circuit of French PWRs

    International Nuclear Information System (INIS)

    Gerardin, J.P.; Donnette, J.E.

    1995-05-01

    The purpose of the loose part detection system is to trigger an alarm whenever it is warranted, to localize, and to provide information on the type of loose part involved and the damages it may provoke. It is therefore indispensable to have efficient instrumentation, beginning with the sensors which must provide us with a response to all mechanical impacts in natural trapping areas (reactor vessel and steam generator water box). A series of mass- and energy-calibrated impacts have been generated on 45 points in the primary cooling system of a nuclear plant unit in the startup phase. This test provided insights into the relationship between sensor signals and various impact parameters such as velocity of impact or loose part mass. Once these parameters were known, it was possible to define a method for evaluating the detection threshold of sensors depending on the way they are mounted. (author)

  5. The Challenges of Distributing Leadership in Irish Post-Primary Schools

    Directory of Open Access Journals (Sweden)

    Margaret O’DONOVAN

    2015-12-01

    Full Text Available This study explores the challenges and opportunities in relation to developing distributed leadership practice in Irish post-primary schools. It considers school leadership within the context of contemporary distributed leadership theory. Associated concepts such as distributed cognition and activity theory are used to frame the study. The study is situated in a space which acknowledges the current complex reality in our schools, where school leadership is characterised by increased workload and an ever-expanding role-definition. Drawing on the empirical findings from semi-structured interviews conducted with principals, deputy principals, post of responsibility holders and teachers in three case-study schools, the study probes: (1 how school leaders (reconstruct a form of leadership suited to the needs of the current reality, by exploring their leadership and management styles; (2 how the internal conditions are created in which distributed leadership can function; (3 the challenges posed by distributed leadership and how they might be overcome. The findings clarify that school leadership is a construct beyond the scope of the principal alone. While there is widespread support for a distributed model of leadership, the concept does not explicitly form part of the discourse in the case-study schools. This poses challenges for school leaders and policy-makers to put mechanisms in place to re-culture schools, to develop teacher-leadership capacity and to reflect on the future direction of leadership in Irish post-primary schools.

  6. The challenges of distributing leadership in Irish post-primary schools

    Directory of Open Access Journals (Sweden)

    Margaret O'Donovan

    2015-09-01

    Full Text Available This study explores the challenges and opportunities in relation to developing distributed leadership practice in Irish post-primary schools. It considers school leadership within the context of contemporary distributed leadership theory. Associated concepts such as distributed cognition and activity theory are used to frame the study. The study is situated in a space which acknowledges the current complex reality in our schools, where school leadership is characterised by increased workload and an ever-expanding role-definition. Drawing on the empirical findings from semi-structured interviews conducted with principals, deputy principals, post of responsibility holders and teachers in three case-study schools, the study probes: (1 how school leaders (reconstruct a form of leadership suited to the needs of the current reality, by exploring their leadership and management styles; (2 how the internal conditions are created in which distributed leadership can function; (3 the challenges posed by distributed leadership and how they might be overcome. The findings clarify that school leadership is a construct beyond the scope of the principal alone. While there is widespread support for a distributed model of leadership, the concept does not explicitly form part of the discourse in the case-study schools. This poses challenges for school leaders and policy-makers to put mechanisms in place to re-culture schools, to develop teacher-leadership capacity and to reflect on the future direction of leadership in Irish post-primary schools.

  7. Role of non destructive techniques for monitoring structural integrity of primary circuit of pressurized water reactor nuclear power plant

    International Nuclear Information System (INIS)

    Sharma, P.K.; Sreenivas, P.

    2015-01-01

    The safety of nuclear installations is ensured by assessing status of primary equipment for performing the intended function reliably and maintaining the integrity of pressure boundaries. The pressure boundary materials undergo material degradation during the plant operation. Pressure boundary materials are subjected to operating stresses and material degradation that results in material properties changes, discontinuities initiation and increase in size of existing discontinuities. Pre-Service Inspection (PSI) is performed to generate reference base line data of initial condition of the pressure boundary. In-Service Inspections (ISI) are performed periodically to confirm integrity of pressure boundaries through comparison with respect to base line data. The non destructive techniques are deployed considering nature of the discontinuities expected to be generated through operating conditions and degradation mechanisms. The paper is prepared considering Pressurized Water Reactor (PWR) Nuclear Power Plant. The paper describes the degradation mechanisms observed in the PWR nuclear power plants and salient aspect of PSI and ISI and considerations in selecting non destructive testing. The paper also emphasises on application of acoustic emission (AE) based condition monitoring systems that can supplement in-service inspections for detecting and locating discontinuities in pressure boundaries. Criticality of flaws can be quantitatively evaluated by determining their size through in-service inspection. Challenges anticipated in deployment of AE based monitoring system and solutions to cater those challenges are also discussed. (author)

  8. Corrosion of high temperature alloys in the primary circuit helium of high temperature gas cooled reactors. Pt. 2

    International Nuclear Information System (INIS)

    Quadakkers, W.J.

    1985-01-01

    The reactive impurities H 2 O, CO, H 2 and CH 4 which are present in the primary coolant helium of high temperature gas-cooled reactors can cause scale formation, internal oxidation and carburization or decarburization of the high temperature structural alloys. In Part 1 of this contribution a theoretical model was presented, which allows the explanation and prediction of the observed corrosion effects. The model is based on a classical stability diagram for chromium, modified to account for deviations from equilibrium conditions caused by kinetic factors. In this paper it is shown how a stability diagram for a commercial alloy can be constructed and how this can be used to correlate the corrosion results with the main experimental parameters, temperature, gas and alloy composition. Using the theoretical model and the presented experimental results, conditions are derived under which a protective chromia based surface scale will be formed which prevents a rapid transfer of carbon between alloy and gas atmosphere. It is shown that this protective surface oxide can only be formed if the carbon monoxide pressure in the gas exceeds a critical value. Psub(CO), which depends on temperature and alloy composition. Additions of methane only have a limited effect provided that the methane/water ratio is not near to, or greater than, a critical value of around 100/1. The influence of minor alloying additions of strong oxide forming elements, commonly present in high temperature alloys, on the protective properties of the chromia surface scales and the kinetics of carbon transfer is illustrated. (orig.) [de

  9. Genetic and clinical characteristics of primary and secondary glioblastoma is associated with differential molecular subtype distribution

    OpenAIRE

    Li, Rui; Li, Hailin; Yan, Wei; Yang, Pei; Bao, Zhaoshi; Zhang, Chuanbao; Jiang, Tao; You, Yongping

    2015-01-01

    Glioblastoma multiforme (GBM) is classified into primary (pGBM) or secondary (sGBM) based on clinical progression. However, there are some limits to this classification for insight into genetically and clinically distinction between pGBM and sGBM. The aim of this study is to characterize pGBM and sGBM associating with differential molecular subtype distribution. Whole transcriptome sequencing data was used to assess the distribution of molecular subtypes and genetic alterations in 88 pGBM and...

  10. Power distribution and substrate noise coupling investigations on the behavioral level for photon counting imaging readout circuits

    International Nuclear Information System (INIS)

    Lundgren, Jan; Abdalla, Suliman; O'Nils, Mattias; Oelmann, Bengt

    2007-01-01

    In modern mixed-signal system design, there are increasing problems associated with noise coupling caused by switching digital parts to sensitive analog parts. As a consequence, there is a growing necessity to understand these problems. In order to avoid costly design iterations, noise coupling simulations should be initiated as early as possible in the design chain. The problems associated with on-chip noise coupling have been discovered in photon counting pixel detector readout systems, where the level of integration of analog and digital circuits is very high on a very small area, and it would appear that these problems will continue to increase for future system designs in this field. This paper deals with the functionality of utilizing behavioral level models for simulating noise coupling in these readout systems. The methods and models are described and simulation results are shown for a photon counting pixel detector readout system

  11. Multiuser remote access to distributed heterogeneous system of programmable logic based laboratory equipment for remote digital circuits design labs

    Directory of Open Access Journals (Sweden)

    Mikhail N. Yokhin

    2017-12-01

    Full Text Available The paper contains an analysis of perspective structures of software and hardware equipment of universal digital design laboratories with the purpose of enabling laboratory classes of digital circuit design to be taken remotely. Implementation characteristics and usage experience of some of those structures applied to labs on several hardware related courses of « Computer science and computer engineering» program in NRNU MEPhI are presented. The paper also considers different aspects of usage of remote access enabled laboratory which should be taken into account to substantiate laboratory configuration from technical and economical standpoints. To increase equipment usage efficiency an approach to group several distinct projects to place them on a single FPGA chip is proposed. The paper shows advisability and gives an example of parametrizable virtual stand for remote debugging of FPGA projects.

  12. Computer programmes of the Power Research Institute for the analysis of processes in the primary coolant circuit and in the containment of a WWER plant in a loss-of-coolant accident

    International Nuclear Information System (INIS)

    Misak, J.

    1976-01-01

    A brief description is given of computer programmes for the analysis of loss-of-coolant accidents (LOCA) in WWER type reactors. The LENKA programme is intended for the thermal and hydraulic analysis of the consequences of such accidents in the primary coolant circuit. The SICHTA programme is intended for the detailed calculation of the time dependence of the axial and radial distribution of heat in fuel rods from steady-state to the flooding of the core. CHEMLOC is intended for the analysis of the heat history of the core and the extent of chemical reactions in LOCA when the emergency core cooling system is not operating. The TRACO I is intended for the analysis of the initial stage of the transient process in a full-pressure containment after LOCA (the computation of the time and spatial dependences of pressures and temperatures). TRACO III is intended for the computation of the long-term time dependence of pressure and temperature in the full-pressure containment after LOCA. (B.S.)

  13. Resonance circuits for adiabatic circuits

    Directory of Open Access Journals (Sweden)

    C. Schlachta

    2003-01-01

    Full Text Available One of the possible techniques to reduces the power consumption in digital CMOS circuits is to slow down the charge transport. This slowdown can be achieved by introducing an inductor in the charging path. Additionally, the inductor can act as an energy storage element, conserving the energy that is normally dissipated during discharging. Together with the parasitic capacitances from the circuit a LCresonant circuit is formed.

  14. Visualizing Metal Content and Intracellular Distribution in Primary Hippocampal Neurons with Synchrotron X-Ray Fluorescence.

    Directory of Open Access Journals (Sweden)

    Robert A Colvin

    Full Text Available Increasing evidence suggests that metal dyshomeostasis plays an important role in human neurodegenerative diseases. Although distinctive metal distributions are described for mature hippocampus and cortex, much less is known about metal levels and intracellular distribution in individual hippocampal neuronal somata. To solve this problem, we conducted quantitative metal analyses utilizing synchrotron radiation X-Ray fluorescence on frozen hydrated primary cultured neurons derived from rat embryonic cortex (CTX and two regions of the hippocampus: dentate gyrus (DG and CA1. Comparing average metal contents showed that the most abundant metals were calcium, iron, and zinc, whereas metals such as copper and manganese were less than 10% of zinc. Average metal contents were generally similar when compared across neurons cultured from CTX, DG, and CA1, except for manganese that was larger in CA1. However, each metal showed a characteristic spatial distribution in individual neuronal somata. Zinc was uniformly distributed throughout the cytosol, with no evidence for the existence of previously identified zinc-enriched organelles, zincosomes. Calcium showed a peri-nuclear distribution consistent with accumulation in endoplasmic reticulum and/or mitochondria. Iron showed 2-3 distinct highly concentrated puncta only in peri-nuclear locations. Notwithstanding the small sample size, these analyses demonstrate that primary cultured neurons show characteristic metal signatures. The iron puncta probably represent iron-accumulating organelles, siderosomes. Thus, the metal distributions observed in mature brain structures are likely the result of both intrinsic neuronal factors that control cellular metal content and extrinsic factors related to the synaptic organization, function, and contacts formed and maintained in each region.

  15. A new evolutionary solution method for dynamic expansion planning of DG-integrated primary distribution networks

    International Nuclear Information System (INIS)

    Ahmadigorji, Masoud; Amjady, Nima

    2014-01-01

    Highlights: • A new dynamic distribution network expansion planning model is presented. • A Binary Enhanced Particle Swarm Optimization (BEPSO) algorithm is proposed. • A Modified Differential Evolution (MDE) algorithm is proposed. • A new bi-level optimization approach composed of BEPSO and MDE is presented. • The effectiveness of the proposed optimization approach is extensively illustrated. - Abstract: Reconstruction in the power system and appearing of new technologies for generation capacity of electrical energy has led to significant innovation in Distribution Network Expansion Planning (DNEP). Distributed Generation (DG) includes the application of small/medium generation units located in power distribution networks and/or near the load centers. Appropriate utilization of DG can affect the various technical and operational indices of the distribution network such as the feeder loading, energy losses and voltage profile. In addition, application of DG in proper size is an essential tool to achieve the DG maximum potential benefits. In this paper, a time-based (dynamic) model for DNEP is proposed to determine the optimal size, location and installation year of DG in distribution system. Also, in this model, the Optimal Power Flow (OPF) is exerted to determine the optimal generation of DGs for every potential solution in order to minimize the investment and operation costs following the load growth in a specified planning period. Besides, the reinforcement requirements of existing distribution feeders are considered, simultaneously. The proposed optimization problem is solved by the combination of evolutionary methods of a new Binary Enhanced Particle Swarm Optimization (BEPSO) and Modified Differential Evolution (MDE) to find the optimal expansion strategy and solve OPF, respectively. The proposed planning approach is applied to two typical primary distribution networks and compared with several other methods. These comparisons illustrate the

  16. Electronic circuit encyclopedia 2

    International Nuclear Information System (INIS)

    Park, Sun Ho

    1992-10-01

    This book is composed of 15 chapters, which are amplification of weak signal and measurement circuit audio control and power amplification circuit, data transmission and wireless system, forwarding and isolation, signal converting circuit, counter and comparator, discriminator circuit, oscillation circuit and synthesizer, digital and circuit on computer image processing circuit, sensor drive circuit temperature sensor circuit, magnetic control and application circuit, motor driver circuit, measuring instrument and check tool and power control and stability circuit.

  17. Electronic circuit encyclopedia 2

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sun Ho

    1992-10-15

    This book is composed of 15 chapters, which are amplification of weak signal and measurement circuit audio control and power amplification circuit, data transmission and wireless system, forwarding and isolation, signal converting circuit, counter and comparator, discriminator circuit, oscillation circuit and synthesizer, digital and circuit on computer image processing circuit, sensor drive circuit temperature sensor circuit, magnetic control and application circuit, motor driver circuit, measuring instrument and check tool and power control and stability circuit.

  18. Primary and Aggregate Size Distributions of PM in Tail Pipe Emissions form Diesel Engines

    Science.gov (United States)

    Arai, Masataka; Amagai, Kenji; Nakaji, Takayuki; Hayashi, Shinji

    Particulate matter (PM) emission exhausted from diesel engine should be reduced to keep the clean air environment. PM emission was considered that it consisted of coarse and aggregate particles, and nuclei-mode particles of which diameter was less than 50nm. However the detail characteristics about these particles of the PM were still unknown and they were needed for more physically accurate measurement and more effective reduction of exhaust PM emission. In this study, the size distributions of solid particles in PM emission were reported. PMs in the tail-pipe emission were sampled from three type diesel engines. Sampled PM was chemically treated to separate the solid carbon fraction from other fractions such as soluble organic fraction (SOF). The electron microscopic and optical-manual size measurement procedures were used to determine the size distribution of primary particles those were formed through coagulation process from nuclei-mode particles and consisted in aggregate particles. The centrifugal sedimentation method was applied to measure the Stokes diameter of dry-soot. Aerodynamic diameters of nano and aggregate particles were measured with scanning mobility particle sizer (SMPS). The peak aggregate diameters detected by SMPS were fallen in the same size regime as the Stokes diameter of dry-soot. Both of primary and Stokes diameters of dry-soot decreased with increases of engine speed and excess air ratio. Also, the effects of fuel properties and engine types on primary and aggregate particle diameters were discussed.

  19. A calculation model for primary intensity distributions from cylindrically symmetric x-ray lenses

    International Nuclear Information System (INIS)

    Hristov, Dimitre; Maltz, Jonathan

    2008-01-01

    A calculation model for the quantitative prediction of primary intensity fluence distributions obtained by the Bragg diffraction focusing of kilovoltage radiation by cylindrical x-ray lenses is presented. The mathematical formalism describes primary intensity distributions from cylindrically-symmetric x-ray lenses, with a planar isotropic radiation source located in a plane perpendicular to the lens axis. The presence of attenuating medium inserted between the lens and the lens focus is accounted for by energy-dependent attenuation. The influence of radiation scattered within the media is ignored. Intensity patterns are modeled under the assumption that photons that are not interacting with the lens are blocked out at any point of interest. The main characteristics of the proposed calculation procedure are that (i) the application of vector formalism allows universal treatment of all cylindrical lenses without the need of explicit geometric constructs; (ii) intensity distributions resulting from x-ray diffraction are described by a 3D generalization of the mosaic spread concept; (iii) the calculation model can be immediately coupled to x-ray diffraction simulation packages such as XOP and Shadow. Numerical simulations based on this model are to facilitate the design of focused orthovoltage treatment (FOT) systems employing cylindrical x-ray lenses, by providing insight about the influence of the x-ray source and lens parameters on quantities of dosimetric interest to radiation therapy

  20. Bose-type distribution and primary cosmic ray nucleon spectrum from sea-level muon spectrum

    CERN Document Server

    Bhattacharya, D P; Roychowdhury, R K

    1976-01-01

    The recent CERN Intersecting Storage Ring cross section data on the p +p to pi /sup +or-/+X inclusive reactions have been analysed using the Bose-type distribution of the form E(d/sup 3/ sigma )/(d/sup 3/p)=(Axs /sup 1/2/)/(exp( epsilon ( lambda )/T)-1) proposed by Hoang (1973). This formula has been used to derive the cosmic ray primary nucleon spectrum from the sea-level muon spectrum. It is found that the primary spectrum obeys the following relation: N(E/sub p/)dE/sub p /=2.06E/sub p//sup -2.64/dE/sub p/. The result has been compared with the recent experimental data and theoretical predictions given by different authors. (11 refs).

  1. Specific features of energy and spatial distribution of primary knocked-out atoms in monocrystals

    International Nuclear Information System (INIS)

    Taratin, A.M.; Vorob'ev, S.A.

    1978-01-01

    By simulation trajectories of 0.2 MeV protons in 1 μm thick Al monocrystal, the energy and spatial distributions of primary atoms knocked out by the protons (PKA) have been studied. Different orientations of the incident beam axis relative to the densely packed direction in the case of ''quasichanneling'' and ''chaotic'' scattering of particles by the crystal have been researched. The depth dependence of the number of generated PKA, their distribution in the plane transverse to the preferred direction, and the energy spectrum of PKA have been obtained. It is shown that the PKA volume density is higher than that obtained using evaluations not accounting for the crystalline structure, and the energy spectrum contains more low energy PKAs. A concept of the cross section of the PKA production on an atomic chain is introduced for ipterpretation of the data obtained

  2. Energy efficiency in arenas : the effect of the distribution circuit on the surface ice temperature; L'efficacite energetique dans les arenas : effet du circuit de distribution sur la temperature de surface de la glace

    Energy Technology Data Exchange (ETDEWEB)

    Bellache, O.; Cummins, R.; Lavallee, H. [Systeme Energie TST, Laval, PQ (Canada)

    2009-03-15

    The ice in most arenas is cooled by brine chillers which consume large amounts of energy. The pump alone that circulates the brine in the piping system underneath the cement consumes as much as 15 per cent of the energy required to cool the ice. This article described a new brine system for skating rinks that has been used in 20 arenas in Montreal. The brine specifications in the arenas were first updated. Then, the commonly used two-pass brine distribution systems with evaporators connected in parallel were replaced with a four-pass brine distribution system with evaporators connected in series. Brine flow was reduced by half and pump horsepower was also significantly reduced while maintaining sufficient fluid velocity in the heat exchangers. Money was also saved because less salt was needed to top up the system. The new design for the brine system is recommended for replacing corroded headers, because payback can be immediate. The new system maintains optimal ice conditions. While the ice quality remains the same, the money saved is substantial, notably 8,500 per rink per year. 3 refs., 9 figs.

  3. Supply and distribution of primary healthcare registered nurses in british columbia.

    Science.gov (United States)

    Wong, Sabrina T; Watson, Diane E; Young, Ella; Mooney, Dawn

    2009-11-01

    WHAT DID WE DO?: This study uses an existing data source to (a) describe the population and geographic distribution of registered nurses (RNs) working in primary healthcare (PHC) in British Columbia, (b) compare this workforce to PHC physicians and (c) assess the distribution of PHC-RNs relative to population health status. WHAT DID WE LEARN?: Of the 27,570 practising RNs in British Columbia in 2000, there were 3,179 (12%) in the PHC workforce. This translates into 147 people per practising RN and 1,277 people per PHC-RN. In 2000, there were 990 people per PHC physician. PHC-RNs represented 43% of the combined PHC workforce of physicians and RNs. A large proportion (47%) of PHC-RNs worked in community health centres, whereas less than 2% worked in physicians' offices. Geographic distribution of PHC-RNs is similar to the distribution of PHC physicians and is not associated with population health status. WHAT ARE THE IMPLICATIONS?: There seem to be sufficient PHC-RNs to implement policy objectives in support of interdisciplinary PHC teams, but physicians and nurses will increasingly need to practice in the same location or have access to electronic information systems to support coordination, continuity and comprehensiveness of PHC. The PHC workforce could be better deployed to align with population health status.

  4. Mutual influences of rated currents, short circuit levels, fault durations and integrated protective schemes for industrial distribution MV switchgears

    Energy Technology Data Exchange (ETDEWEB)

    Gaidano, G. (FIAT Engineering, Torino, Italy); Lionetto, P.F.; Pelizza, C.; Tommazzolli, F.

    1979-01-01

    This paper deals with the problem of integrated and coordinated design of distribution systems, as regards the definition of system structure and parameters together with protection criteria and schemes. Advantages in system operation, dynamic response, heavier loads with reduced machinery rating margins and overall cost reduction, can be achieved. It must be noted that MV switchgears installed in industrial main distribution substations are the vital nodes of the distribution system. Very large amounts of power (up to 100 MW and more) are conveyed through MV busbars, coming from Utility and from in-plant generators and outgoing to subdistribution substations, to step-down transformers and to main concentrated loads (big drivers, furnaces etc.). Criteria and methods already studied and applied to public distribution are examined to assess service continuity and economics by means of the reduction of thermal stresses, minimization of disturbances and improvement of system stability. The life of network components depends on sizing, on fault energy levels and on probability of fault occurrence. Constructional measures and protection schemes, which reduce probability and duration of faults, are the most important tools to improve overall reliability. The introduction of advanced techniques, mainly based on computer application, not only allows drastic reduction of fault duration, but also permits the system to operate, under any possible contingency, in the optimal conditions, as the computer provides adaptive control. This mode of system management makes it possible to size network components with reference to the true magnitude of system quantities, avoiding expensive oversizing connected to the unflexibility of conventional protection and control schemes.

  5. Structure of electron tracks in water. 2. Distribution of primary ionizations and excitations in water radiolysis

    International Nuclear Information System (INIS)

    Pimblott, S.M.; Mozumder, A.

    1991-01-01

    A procedure for the calculation of entity-specific ionization and excitation probabilities for water radiolysis at low linear energy transfer (LET) has been developed. The technique pays due attention to the effects of the ionization threshold and the energy dependence of the ionization efficiency. The numbers of primary ionizations and excitations are not directly proportional to the spur energy. At a given spur energy, ionization follows a binomial distribution subject to an energetically possible maximum. The excitation distribution for a spur of given energy and with a given number of ionizations is given by a geometric series. The occurrence probabilities depend upon the cross sections of ionization, excitation, and other inferior processes. Following the low-LET radiolysis of liquid water the most probable spurs contain one ionization, two ionizations, or one ionization and one excitation, while in water vapor they contain either one ionization or one excitation. In liquid water the most probable outcomes for spurs corresponding to the most probable energy loss (22 eV) and to the mean energy loss (38 eV) are one ionization and one excitation, and two ionizations and one excitation, respectively. In the vapor, the most probable energy loss is 14 eV which results in one ionization or one excitation and the mean energy loss is 34 eV for which the spur of maximum probability contains one ionization and two excitations. The total calculated primary yields for low-LET radiolysis are in approximate agreement with experiment in both phases

  6. Distribution and utilization of curative primary healthcare services in Lahej, Yemen.

    Science.gov (United States)

    Bawazir, A A; Bin Hawail, T S; Al-Sakkaf, K A Z; Basaleem, H O; Muhraz, A F; Al-Shehri, A M

    2013-09-01

    No evidence-based data exist on the availability, accessibility and utilization of healthcare services in Lahej Governorate, Yemen. The aim of this study was to assess the distribution and utilization of curative services in primary healthcare units and centres in Lahej. Cross-sectional study (clustering sample). This study was conducted in three of the 15 districts in Lahej between December 2009 and August 2010. Household members were interviewed using a questionnaire to determine sociodemographic characteristics and types of healthcare services available in the area. The distribution of health centres, health units and hospitals did not match the size of the populations or areas of the districts included in this study. Geographical accessibility was the main obstacle to utilization. Factors associated with the utilization of curative services were significantly related to the time required to reach the nearest facility, seeking curative services during illness and awareness of the availability of health facilities (P < 0.01). There is an urgent need to look critically and scientifically at the distribution of healthcare services in the region in order to ensure accessibility and quality of services. Copyright © 2013 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  7. A Quantitative Study of the Relationship between Distributed Leadership and Organizational Citizenship Behavior: Perceptions of Turkish Primary School Teachers

    Science.gov (United States)

    Kilinç, Ali Çagatay

    2014-01-01

    The purpose of this study was to determine the relationship between primary school teachers' perceptions on distributed leadership and organizational citizenship behaviors (OCBs). A total of 258 teachers employed in 14 primary schools located in Kastamonu, Turkey participated in this study. Data of the study was collected through "Distributed…

  8. Improvement and qualification of ultrasonic testing of dissimilar welds in the primary circuit of NPPs; Verbesserung und Qualifizierung der Ultraschallpruefung von Mischnaehten im Primaerkreis von KKW

    Energy Technology Data Exchange (ETDEWEB)

    Mitzscherling, Steffen; Barth, Enrico; Homann, Tobias; Prager, Jens [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany); Goetschel, Sebastian; Weiser, Martin [Konrad-Zuse-Zentrum fuer Informationstechnik Berlin (ZIB) (Germany)

    2017-08-01

    The austenitic and dissimilar welds found in the primary circuit of nuclear power plants are not only extremely relevant to safety but also place very high demands on material testing. In addition to limited accessibility, the macroscopic structure of the weld seam is of paramount importance for ultrasound testing. In order to reliably determine material errors in position and size, the grain orientations and the elastic constants of the anisotropic weld bead structure must be known. The following work steps are used for the imaging representation of possible material defects: First, the weld seam is sounded in order to be able to determine important weld seam parameters, such as, for example, the grain orientation, using an inverse method. On the basis of these parameters, the sound paths are simulated in the next step by means of raytracing (RT). Finally, this RT simulation is assigned the measurement data (A-scans) from different transmitter and receiver positions and superimposed according to the Synthetic Aperature Focusing Technique (SAFT) method. The combination of inverse process, RT and SAFT also ensures a correct visualization of the faults in anisotropic materials. We explain these three methods and present the test arrangement of test specimens with artificial test errors. Measurement data as well as their evaluation are compared with the results of a CIVA simulation. [German] Die im Primaerkreislauf von Kernkraftwerken anzutreffenden austenitischen Schweiss- und Mischnaehte sind nicht nur extrem sicherheitsrelevant, sondern stellen auch sehr hohe Anforderungen an die Materialpruefung. Neben der eingeschraenkten Zugaenglichkeit ist das makroskopische Gefuege der Schweissnaht fuer die Pruefung mit Ultraschall von hoechster Bedeutung. Um Materialfehler zuverlaessig in Position und Groesse bestimmen zu koennen, muessen die Kornorientierungen und die elastischen Konstanten des anisotropen Schweissnahtgefueges bekannt sein. Fuer die bildgebende Darstellung

  9. Arithmetic circuits for DSP applications

    CERN Document Server

    Stouraitis, Thanos

    2017-01-01

    Arithmetic Circuits for DSP Applications is a complete resource on arithmetic circuits for digital signal processing (DSP). It covers the key concepts, designs and developments of different types of arithmetic circuits, which can be used for improving the efficiency of implementation of a multitude of DSP applications. Each chapter includes various applications of the respective class of arithmetic circuits along with information on the future scope of research. Written for students, engineers, and researchers in electrical and computer engineering, this comprehensive text offers a clear understanding of different types of arithmetic circuits used for digital signal processing applications. The text includes contributions from noted researchers on a wide range of topics, including a review o circuits used in implementing basic operations like additions and multiplications; distributed arithmetic as a technique for the multiplier-less implementation of inner products for DSP applications; discussions on look ...

  10. Developmental distribution of the plasma membrane-enriched proteome in the maize primary root growth zone

    Directory of Open Access Journals (Sweden)

    Zhe eZhang

    2013-03-01

    Full Text Available Within the growth zone of the maize primary root, there are well-defined patterns of spatial and temporal organization of cell division and elongation. However, the processes underlying this organization remain poorly understood. To gain additional insights into the differences amongst the defined regions, we performed a proteomic analysis focusing on fractions enriched for plasma membrane (PM proteins. The PM is the interface between the plant cell and the apoplast and/or extracellular space. As such, it is a key structure involved in the exchange of nutrients and other molecules as well as in the integration of signals that regulate growth and development. Despite the important functions of PM-localized proteins in mediating these processes, a full understanding of dynamic changes in PM proteomes is often impeded by low relative concentrations relative to total proteins. Using a relatively simple strategy of treating microsomal fractions with Brij-58 detergent to enrich for PM proteins, we compared the developmental distribution of proteins within the root growth zone which revealed a number of previously known as well as novel proteins with interesting patterns of abundance. For instance, the quantitative proteomic analysis detected a gradient of PM aquaporin proteins similar to that previously reported using immunoblot analyses, confirming the veracity of this strategy. Cellulose synthases increased in abundance with increasing distance from the root apex, consistent with expected locations of cell wall deposition. The similar distribution pattern for Brittle-stalk-2-like protein 3 implicate that this protein may also have cell wall related functions. These results show that the simplified PM enrichment method previously demonstrated in Arabidopsis can be successfully applied to completely unrelated plant tissues and provide insights into differences in the PM proteome throughout growth and development zones of the maize primary root.

  11. Developmental distribution of the plasma membrane-enriched proteome in the maize primary root growth zone.

    Science.gov (United States)

    Zhang, Zhe; Voothuluru, Priyamvada; Yamaguchi, Mineo; Sharp, Robert E; Peck, Scott C

    2013-01-01

    Within the growth zone of the maize primary root, there are well-defined patterns of spatial and temporal organization of cell division and elongation. However, the processes underlying this organization remain poorly understood. To gain additional insights into the differences amongst the defined regions, we performed a proteomic analysis focusing on fractions enriched for plasma membrane (PM) proteins. The PM is the interface between the plant cell and the apoplast and/or extracellular space. As such, it is a key structure involved in the exchange of nutrients and other molecules as well as in the integration of signals that regulate growth and development. Despite the important functions of PM-localized proteins in mediating these processes, a full understanding of dynamic changes in PM proteomes is often impeded by low relative concentrations relative to total proteins. Using a relatively simple strategy of treating microsomal fractions with Brij-58 detergent to enrich for PM proteins, we compared the developmental distribution of proteins within the root growth zone which revealed a number of previously known as well as novel proteins with interesting patterns of abundance. For instance, the quantitative proteomic analysis detected a gradient of PM aquaporin proteins similar to that previously reported using immunoblot analyses, confirming the veracity of this strategy. Cellulose synthases increased in abundance with increasing distance from the root apex, consistent with expected locations of cell wall deposition. The similar distribution pattern for Brittle-stalk-2-like protein implicates that this protein may also have cell wall related functions. These results show that the simplified PM enrichment method previously demonstrated in Arabidopsis can be successfully applied to completely unrelated plant tissues and provide insights into differences in the PM proteome throughout growth and development zones of the maize primary root.

  12. Distribution of essential medicines to primary care institutions in Hubei of China: effects of centralized procurement arrangements.

    Science.gov (United States)

    Yang, Lianping; Huang, Cunrui; Liu, Chaojie

    2017-11-14

    Poor distribution of essential medicines to primary care institutions has attracted criticism since China adopted provincial centralized regional tendering and procurement systems. This study evaluated the impact of new procurement arrangements that limit the number of distributors at the county level in Hubei province, China. Procurement ordering and distribution data were collected from four counties that pioneered a new distribution arrangement (commencing September 2012) compared with six counties that continued the existing arrangement over the period from August 2011 to September 2013. The new arrangement allowed primary care institutions and/or suppliers to select a local distributor from a limited panel (from 3 to 5) of government nominated distributors. Difference-in-differences analyses were performed to assess the impact of the new arrangements on delivery and receipt of essential medicines. Overall, the new distribution arrangement has not improved distribution of essential medicines to primary care institutions. On the contrary, we found a 7.78-19.85 percentage point (p Procurement arrangements need to consider the special characteristics of rural facilities. In a county, there are more rural primary care institutions than urban ones. On average, rural primary care institutions demand more and are more geographically dispersed compared to their urban counterparts, which may impose increased distribution costs.

  13. Controllable circuit

    DEFF Research Database (Denmark)

    2010-01-01

    A switch-mode power circuit comprises a controllable element and a control unit. The controllable element is configured to control a current in response to a control signal supplied to the controllable element. The control unit is connected to the controllable element and provides the control...

  14. Circuit Training.

    Science.gov (United States)

    Nelson, Jane B.

    1998-01-01

    Describes a research-based activity for high school physics students in which they build an LC circuit and find its resonant frequency of oscillation using an oscilloscope. Includes a diagram of the apparatus and an explanation of the procedures. (DDR)

  15. Determining of the nuclear composition of primary cosmic rays from the experimental distributions of multiple muons in atmospheric showers

    International Nuclear Information System (INIS)

    Beshtoev, Kh.M.

    1993-01-01

    Various approaches are discussed for determining the nuclear composition of the primary cosmic radiation from the distributions of multiple muons. Results are presented of calculations of the distributions of multiple muons for A 1 , A 4 , A 14 , A 26 , A 56 nuclei for an infinite plane and for the underground scintillation telescope of the Institute for Nuclear Research of the Academy of Sciences of Russia.The most suitable technique for determination of the primary nuclear composition of cosmic rays from the distribution of multiple muons is shown to be the approximate solution of a set of N equations, in which the respective coefficients of the contributions of various nuclei A i (i=1-N) to the primary composition serve as variables, while the remaining parts of these equations are the distributions of multiple muons obtained experimentally. 7 refs.; 2 tabs

  16. An Icepak-PSpice Co-Simulation Method to Study the Impact of Bond Wires Fatigue on the Current and Temperature Distribution of IGBT Modules under Short-Circuit

    DEFF Research Database (Denmark)

    Wu, Rui; Iannuzzo, Francesco; Wang, Huai

    2014-01-01

    Bond wires fatigue is one of the dominant failure mechanisms of IGBT modules. Prior-art research mainly focuses on its impact on the end-of-life failure, while its effect on the short-circuit capability of IGBT modules is still an open issue. This paper proposes a new electro-thermal simulation...... approach enabling analyze the impact of the bond wires fatigue on the current and temperature distribution on IGBT chip surface under short-circuit. It is based on an Icepack-PSpice co-simulation by taking the advantage of both a finite element thermal model and an advanced PSpice-based multi-cell IGBT...

  17. Distribution of Ca, Fe, Cu and Zn in primary colorectal cancer and secondary colorectal liver metastases

    International Nuclear Information System (INIS)

    Al-Ebraheem, A.; Mersov, A.; Gurusamy, K.; Farquharson, M.J.

    2010-01-01

    A microbeam synchrotron X-ray fluorescence (μSRXRF) technique has been used to determine the localization and the relative concentrations of Zn, Cu, Fe and Ca in primary colorectal cancer and secondary colorectal liver metastases. 24 colon and 23 liver samples were examined, all of which were formalin fixed tissues arranged as microarrays of 1.0 mm diameter and 10 μm thickness. The distribution of these metals was compared with light transmission images of adjacent sections that were H and E stained to reveal the location of the cancer cells. Histological details were provided for each sample which enable concentrations of all elements in different tissue types to be compared. In the case of liver, significant differences have been found for all elements when comparing tumour, normal, necrotic, fibrotic, and blood vessel tissues (Kruskal Wallis Test, P<0.0001). The concentrations of all elements have also been found to be significantly different among tumour, necrotic, fibrotic, and mucin tissues in the colon samples (Kruskal Wallis Test, P<0.0001). The concentrations of all elements have been compared between primary colorectal samples and colorectal liver metastases. Concentration of Zn, Cu, Fe and Ca are higher in all types of liver tissues compared to those in the colon tissues. Comparing liver tumour and colon tumour samples, significant differences have been found for all elements (Mann Whitney, P<0.0001). For necrotic tissues, significant increase has been found for Zn, Ca, Cu and Fe (Mann Whitney, P<0.0001 for Fe and Zn, 0.014 for Ca, and 0.001 for Cu). The liver fibrotic levels of Zn, Ca, Cu and Fe were higher than the fibrotic colon areas (independent T test, P=0.007 for Zn and Mann Whitney test P<0.0001 for Cu, Fe and Ca). For the blood vessel tissue, the analysis revealed that the difference was only significant for Fe (P=0.009) from independent T test.

  18. Unequal socioeconomic distribution of the primary care workforce: whole-population small area longitudinal study.

    Science.gov (United States)

    Asaria, Miqdad; Cookson, Richard; Fleetcroft, Robert; Ali, Shehzad

    2016-01-19

    To measure changes in socioeconomic inequality in the distribution of family physicians (general practitioners (GPs)) relative to need in England from 2004/2005 to 2013/2014. Whole-population small area longitudinal data linkage study. England from 2004/2005 to 2013/2014. 32,482 lower layer super output areas (neighbourhoods of 1500 people on average). Slope index of inequality (SII) between the most and least deprived small areas in annual full-time equivalent GPs (FTE GPs) per 100,000 need adjusted population. In 2004/2005, inequality in primary care supply as measured by the SII in FTE GPs was 4.2 (95% CI 3.1 to 5.3) GPs per 100,000. By 2013/2014, this SII had fallen to -0.7 (95% CI -2.5 to 1.1) GPs per 100,000. The number of FTE GPs per 100,000 serving the most deprived fifth of small areas increased over this period from 54.0 to 60.5, while increasing from 57.2 to 59.9 in the least deprived fifth, so that by the end of the study period there were more GPs per 100,000 need adjusted population in the most deprived areas than in the least deprived. The increase in GP supply in the most deprived fifth of neighbourhoods was larger in areas that received targeted investment for establishing new practices under the 'Equitable Access to Primary Medical Care'. There was a substantial reduction in socioeconomic inequality in family physician supply associated with national policy. This policy may not have completely eliminated socioeconomic inequality in family physician supply since existing need adjustment formulae do not fully capture the additional burden of multimorbidity in deprived neighbourhoods. The small area approach introduced in this study can be used routinely to monitor socioeconomic inequality of access to primary care and to indicate workforce shortages in particular neighbourhoods. http://creativecommons.org/licenses/by/4.0. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to

  19. The grain-size distribution of pyroclasts: Primary fragmentation, conduit sorting or abrasion?

    Science.gov (United States)

    Kueppers, U.; Schauroth, J.; Taddeucci, J.

    2013-12-01

    Explosive volcanic eruptions expel a mixture of pyroclasts and lithics. Pyroclasts, fragments of the juvenile magma, record the state of the magma at fragmentation in terms of porosity and crystallinity. The grain size distribution of pyroclasts is generally considered to be a direct consequence of the conditions at magma fragmentation that is mainly driven by gas overpressure in bubbles, high shear rates, contact with external water or a combination of these factors. Stress exerted by any of these processes will lead to brittle fragmentation by overcoming the magma's relaxation timescale. As a consequence, most pyroclasts exhibit angular shapes. Upon magma fragmentation, the gas pyroclast mixture is accelerated upwards and eventually ejected from the vent. The total grain size distribution deposited is a function of fragmentation conditions and transport related sorting. Porous pyroclasts are very susceptible to abrasion by particle-particle or particle-conduit wall interaction. Accordingly, pyroclastic fall deposits with angular clasts should proof a low particle abrasion upon contact to other surfaces. In an attempt to constrain the degree of particle interaction during conduit flow, monomodal batches of washed pyroclasts have been accelerated upwards by rapid decompression and subsequently investigated for their grain size distribution. In our set-up, we used a vertical cylindrical tube without surface roughness as conduit. We varied grain size (0.125-0.25; 0.5-1; 1-2 mm), porosity (0; 10; 30 %), gas-particle ratio (10 and 40%), conduit length (10 and 28 cm) and conduit diameter (2.5 and 6 cm). All ejected particles were collected after settling at the base of a 3.3 m high tank and sieved at one sieve size below starting size (half-Φ). Grain size reduction showed a positive correlation with starting grain size, porosity and overpressure at the vent. Although milling in a volcanic conduit may take place, porous pyroclasts are very likely to be a primary product

  20. Effects of ultraviolet radiation on rates and size distribution of primary production by Lake Erie phytoplankton

    International Nuclear Information System (INIS)

    Hiriart, V.P.; Greenberg, B.M.; Guildford, S.J.; Smith, R.E.H.

    2002-01-01

    The impact of natural solar ultraviolet radiation (UVR), particularly UVB (297-320 nm), on phytoplankton primary production in Lake Erie was investigated during the spring and summer of 1997. Radiocarbon incorporation and size-selective filtration was used to trace total production and its distribution among particulate and dissolved pools. On average, 1-h exposures produced half the UVB-dependent inhibition of total production realized in 8-h exposures, indicating rapid kinetics of photoinhibition. Cumulative UVB-dependent photoinhibition averaged 36% in 8-h simulated surface exposures. The efficiency of photoinhibition was greater for N-deficient than N-replete communities, but was not related to phytoplankton light history, P limitation, or the dominant genera. The proportion of recently fixed carbon occurring in the dissolved pool after 8-h exposures was significantly greater in higher-UVB treatments, whereas the share in picoplankton (<2 μm) was significantly lower. Significant UVB-dependent inhibition of total production was limited on average to relatively severe exposures, but the rapid kinetics of inhibition and the apparent effects on the allocation of carbon suggest it may be important to the lake's food web. Differences in optical properties and thermal stratification patterns suggested that the relatively turbid west basin was potentially more susceptible to UVR photoinhibition than the more transparent east or central basins. (author)

  1. Head-circumference distribution in a large primary care network differs from CDC and WHO curves.

    Science.gov (United States)

    Daymont, Carrie; Hwang, Wei-Ting; Feudtner, Chris; Rubin, David

    2010-10-01

    To compare currently available head-circumference growth curves to curves constructed from clinical measurements from patients in a large US primary care network (PCN). We performed a retrospective cohort study of 75 412 patients in an urban-suburban PCN. Patients with a birth weight of curves. The PCN curves were most similar to the National Center for Health Statistics (NCHS) curves and were substantially different from the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) curves. The overall proportion of observations above the 95th percentile was 4.9% (PCN), 6.2% (NCHS), 8.6% (CDC), and 14.0% (WHO). The proportion below the 5th percentile was 4.4% (PCN), 5.1% (NCHS), 2.9% (CDC), and 2.3% (WHO). When using the CDC curves, the proportion above the 95th percentile increased from 0.2% for children younger than 2 weeks to 11.8% for children 12 months old. When using the WHO curves, the proportion above the 95th percentile was >5% at all ages, with a maximum of 18.0% for children older than 24 months. The CDC and WHO head-circumference curves describe different distributions than the clinical measurements in our PCN population, especially for children with larger heads. The resulting percentile misclassification may delay diagnosis in children with intracranial pathology in very young infants and spur unnecessary evaluation of healthy children older than 6 months.

  2. IR laser induced reactions: temperature distributions and detection of primary products

    International Nuclear Information System (INIS)

    Bachmann, F.

    1981-12-01

    The products of laser-driven pyrolysis in the gas phase often differ drastically from those of conventional pyrolysis. In this work some reasons for this behaviour are considered. First, temperature distributions in cylindrical cells, filled with SF 6 at low pressure and heated by cw CO 2 laser radiation, are calculated by a simple model. The influence of convection is not taken into account. Comparison of theoretical prediction and corresponding experiments included the temperature-dependent absorption cross section. In the second part we describe a molecular-beam sampling system for real time monitoring of primary products in laser-driven reactions. With this system initial tests were made in nonreacting SF 6 /rare-gas mixtures. The influence of thermal diffusion was indicated by changes in concentration when the laser was switched on and off. A theoretical treatment is given solving the time-dependent heat-conduction and diffusion equation numerically. As an example for reacting systems, the laser-driven pyrolysis of methanol with SF 6 as an absorber was studied. (orig./HT)

  3. LOGIC CIRCUIT

    Science.gov (United States)

    Strong, G.H.; Faught, M.L.

    1963-12-24

    A device for safety rod counting in a nuclear reactor is described. A Wheatstone bridge circuit is adapted to prevent de-energizing the hopper coils of a ball backup system if safety rods, sufficient in total control effect, properly enter the reactor core to effect shut down. A plurality of resistances form one arm of the bridge, each resistance being associated with a particular safety rod and weighted in value according to the control effect of the particular safety rod. Switching means are used to switch each of the resistances in and out of the bridge circuit responsive to the presence of a particular safety rod in its effective position in the reactor core and responsive to the attainment of a predetermined velocity by a particular safety rod enroute to its effective position. The bridge is unbalanced in one direction during normal reactor operation prior to the generation of a scram signal and the switching means and resistances are adapted to unbalance the bridge in the opposite direction if the safety rods produce a predetermined amount of control effect in response to the scram signal. The bridge unbalance reversal is then utilized to prevent the actuation of the ball backup system, or, conversely, a failure of the safety rods to produce the predetermined effect produces no unbalance reversal and the ball backup system is actuated. (AEC)

  4. Computation of aquatic primary production: Extended formalism to include effect of angular and spectral distribution of light

    Digital Repository Service at National Institute of Oceanography (India)

    Sathyendranath, S.; Platt, T.

    and utilization by algal cells. Neglecting the effect of angular distribution on the light absorbed by phytoplankton can lead to underestimation of primary production. For the stations studied as examples, the minimum correction required is 5-l3% for daily, column...

  5. Short- circuit tests of circuit breakers

    OpenAIRE

    Chorovský, P.

    2015-01-01

    This paper deals with short-circuit tests of low voltage electrical devices. In the first part of this paper, there are described basic types of short- circuit tests and their principles. Direct and indirect (synthetic) tests with more details are described in the second part. Each test and principles are explained separately. Oscilogram is obtained from short-circuit tests of circuit breakers at laboratory. The aim of this research work is to propose a test circuit for performing indirect test.

  6. Study of the strength distribution of primary γ-transitions in the decay from superdeformed states in 194Hg

    International Nuclear Information System (INIS)

    Lopez-Martens, A.P.; Doessing, T.; Khoo, T.L.; Korichi, A.; Hannachi, F.; Calderin, I.J.; Lauritsen, T.; Ahmad, I.; Carpenter, M.P.; Fischer, S.M.; Hackman, G.; Janssens, R.V.F.; Nisius, D.; Reiter, P.; Amro, H.; Moore, E.F.

    1999-01-01

    The strength distribution of the primary γ rays in the decay from superdeformed (SD) states is investigated by applying the maximum likelihood method. For the 194 Hg nucleus, 41 primary transitions are identified above 2600 keV. It is concluded that they represent the strongest 10% of the transitions selected stochastically from a Porter-Thomas distribution. This would support the scenario of a statistical decay of SD states via coupling to a compound state at normal deformation. However, the occurrence of several very strong 'one-step linking' transitions is found to have a very small probability. Based on the absence of strong primary transitions from SD states in adjacent nuclei, the situation in 194 Hg is viewed as a very lucky incidence

  7. Collective of mechatronics circuit

    International Nuclear Information System (INIS)

    1987-02-01

    This book is composed of three parts, which deals with mechatronics system about sensor, circuit and motor. The contents of the first part are photo sensor of collector for output, locating detection circuit with photo interrupts, photo sensor circuit with CdS cell and lamp, interface circuit with logic and LED and temperature sensor circuit. The second part deals with oscillation circuit with crystal, C-R oscillation circuit, F-V converter, timer circuit, stability power circuit, DC amp and DC-DC converter. The last part is comprised of bridge server circuit, deformation bridge server, controlling circuit of DC motor, controlling circuit with IC for PLL and driver circuit of stepping motor and driver circuit of Brushless.

  8. Collective of mechatronics circuit

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1987-02-15

    This book is composed of three parts, which deals with mechatronics system about sensor, circuit and motor. The contents of the first part are photo sensor of collector for output, locating detection circuit with photo interrupts, photo sensor circuit with CdS cell and lamp, interface circuit with logic and LED and temperature sensor circuit. The second part deals with oscillation circuit with crystal, C-R oscillation circuit, F-V converter, timer circuit, stability power circuit, DC amp and DC-DC converter. The last part is comprised of bridge server circuit, deformation bridge server, controlling circuit of DC motor, controlling circuit with IC for PLL and driver circuit of stepping motor and driver circuit of Brushless.

  9. A sequential logic circuit for coincidences randomly distributed in 'time' and 'duration', with selection and total sampling

    International Nuclear Information System (INIS)

    Carnet, Bernard; Delhumeau, Michel

    1971-06-01

    The principles of binary analysis applied to the investigation of sequential circuits were used to design a two way coincidence circuit whose input may be, random or periodic variables of constant or variable duration. The output signal strictly reproduces the characteristics of the input signal triggering the coincidence. A coincidence between input signals does not produce any output signal if one of the signals has already triggered the output signal. The characteristics of the output signal in relation to those of the input signal are: minimum time jitter, excellent duration reproducibility and maximum efficiency. Some rules are given for achieving these results. The symmetry, transitivity and non-transitivity characteristics of the edges on the primitive graph are analyzed and lead to some rules for positioning the states on a secondary graph. It is from this graph that the equations of the circuits can be calculated. The development of the circuit and its dynamic testing are discussed. For this testing, the functioning of the circuit is simulated by feeding into the input randomly generated signals

  10. Circuit parties.

    Science.gov (United States)

    Guzman, R

    2000-03-01

    Circuit parties are extended celebrations, lasting from a day to a week, primarily attended by gay and bisexual men in their thirties and forties. These large-scale dance parties move from city to city and draw thousands of participants. The risks for contracting HIV during these parties include recreational drug use and unsafe sex. Limited data exists on the level of risk at these parties, and participants are skeptical of outside help because of past criticism of these events. Health care and HIV advocates can promote risk-reduction strategies with the cooperation of party planners and can counsel individuals to personally reduce their own risk. To convey the message, HIV prevention workers should emphasize positive and community-centered aspects of the parties, such as taking care of friends and avoiding overdose.

  11. Multiple output power supply circuit for an ion engine with shared upper inverter

    Science.gov (United States)

    Cardwell, Jr., Gilbert I. (Inventor); Phelps, Thomas K. (Inventor)

    2001-01-01

    A power supply circuit for an ion engine suitable for a spacecraft is coupled to a bus having a bus input and a bus return. The power supply circuit has a first primary winding of a first transformer. An upper inverter circuit is coupled to the bus input and the first primary winding. The power supply circuit further includes a first lower inverter circuit coupled to the bus return and the first primary winding. The second primary winding of a second transformer is coupled to the upper inverter circuit. A second lower inverter circuit is coupled to the bus return and the second primary winding.

  12. Commutation circuit for an HVDC circuit breaker

    Science.gov (United States)

    Premerlani, William J.

    1981-01-01

    A commutation circuit for a high voltage DC circuit breaker incorporates a resistor capacitor combination and a charging circuit connected to the main breaker, such that a commutating capacitor is discharged in opposition to the load current to force the current in an arc after breaker opening to zero to facilitate arc interruption. In a particular embodiment, a normally open commutating circuit is connected across the contacts of a main DC circuit breaker to absorb the inductive system energy trapped by breaker opening and to limit recovery voltages to a level tolerable by the commutating circuit components.

  13. Coordinated Primary and Secondary Control with Frequency-Bus-Signaling for Distributed Generation and Storage in Islanded Microgrids

    DEFF Research Database (Denmark)

    Wu, Dan; Tang, Fen; Dragicevic, Tomislav

    2013-01-01

    In this paper, a distributed coordinated control scheme based on frequency-bus-signaling (FBS) method for a low-voltage AC three phase microgrid is proposed. The control scheme is composed by two levels. Firstly a primary local control which is different for the DGs and the ESS is proposed. The ESS...... control is implemented to restore the frequency deviation produced by the primary ESS controller while preserving the coordinated control performance. Real-time simulation results show the feasibility of the proposed approach by showing the operation of the microgrid in different scenarios....

  14. Prospective single and multi-phase short-circuit current levels in the Dutch transmission, sub-transmission and distribution grids

    NARCIS (Netherlands)

    Janssen, A.L.J.; van Riet, M.J.M.; Smeets, R.P.P.; Kanters, J.; van den Akker, W.F.; Aanhaanen, G.L.P.

    2012-01-01

    As elsewhere in the world, also in the Netherlands utilities face an increase in the actual and future short-circuit current levels at all voltages. This development is provoked by the required increase in transmission capacity as well as the concentration of power generation capacity. Large

  15. Analog circuit design designing dynamic circuit response

    CERN Document Server

    Feucht, Dennis

    2010-01-01

    This second volume, Designing Dynamic Circuit Response builds upon the first volume Designing Amplifier Circuits by extending coverage to include reactances and their time- and frequency-related behavioral consequences.

  16. Trigger circuit

    International Nuclear Information System (INIS)

    Verity, P.R.; Chaplain, M.D.; Turner, G.D.J.

    1984-01-01

    A monostable trigger circuit comprises transistors TR2 and TR3 arranged with their collectors and bases interconnected. The collector of the transistor TR2 is connected to the base of transistor TR3 via a capacitor C2 the main current path of a grounded base transistor TR1 and resistive means R2,R3. The collector of transistor TR3 is connected to the base of transistor TR2 via resistive means R6, R7. In the stable state all the transistors are OFF, the capacitor C2 is charged, and the output is LOW. A positive pulse input to the base of TR2 switches it ON, which in turn lowers the voltage at points A and B and so switches TR1 ON so that C2 can discharge via R2, R3, which in turn switches TR3 ON making the output high. Thus all three transistors are latched ON. When C2 has discharged sufficiently TR1 switches OFF, followed by TR3 (making the output low again) and TR2. The components C1, C3 and R4 serve to reduce noise, and the diode D1 is optional. (author)

  17. Combining forces. Distributed Leadership and a professional learning community in primary and secondary education

    NARCIS (Netherlands)

    Hulsbos, Frank; Van Langevelde, Stefan; Evers, Arnoud

    2018-01-01

    This report describes an in depth case study of two good practice schools where a professional learning community and distributed leadership are highly developed. The goal of this study was to learn what conditions in the school support a professional learning community and distributed leadership.

  18. Modeling of coherent heat and mass-exchange phenomena for a specter of primary circuit leaks in a NPP with WWER-1000 type reactor

    International Nuclear Information System (INIS)

    Stanev, I.; Mladenova, S.; Hadjiev, V.

    2004-01-01

    Subject of study are the inter-relations between the primary leak parameters, the containment pressure and the functioning of the WWER-1000/V320 plant systems. The model includes systems for normal operation and safety systems, which are actuated in the initial stage of the accident. The studied specter of primary leaks includes diameters from 10 to 60 mm. The model is based on the design features of unit 5 in NPP Kozloduy. This paper presents a fragment of the work, performed jointly by Atoma Consult Ltd and NPP Kozloduy Plc on the validation of the symptom oriented emergency operation procedures for units 5 and 6 in NPP Kozloduy. (authors)

  19. Water quality control program in experimental circuits

    International Nuclear Information System (INIS)

    Cegalla, Miriam A.

    1996-01-01

    The Water Quality Control Program of the Experimental Circuits visualizes studying the water chemistry of the cooling in the primary and secondary circuits, monitoring the corrosion of the systems and studying the mechanism of the corrosion products transport in the systems. (author)

  20. Investigating the Cherenkov light lateral distribution function for primary proton and iron nuclei in extensive air showers

    International Nuclear Information System (INIS)

    Al-Rubaiee, A.A.; Hashim, U.; Al-Douri, Y.

    2015-01-01

    The lateral distribution function (LDF) of Cherenkov radiation in extensive air showers (EAS) was simulated by CORSIKA program for the conditions of Yakutsk Cherenkov array at high energy range (10 13 -10 16 eV) for two primary particles (p and Fe) for different zenith angles. Using Breit-Wigner function for analyzing Cherenkov light LDF, a parameterization of Cherenkov light LDF was reconstructed by depending on CORSIKA simulation as a function of primary energy. The comparison between the estimated Cherenkov light LDF and the LDF that was measured on the Yakutsk EAS array gives the ability of particle identification that initiated the shower and determination of particle's energy around the knee region. The extrapolation of approximated Cherenkov light LDF for energies 20 and 30 PeV was obtained for primary particles (p and Fe)

  1. Maximum forseeable accident analysis made by a sodium leak on the BN-800 primary circuit and the more constraining accident development scenario

    International Nuclear Information System (INIS)

    Ivanenko, V.N.; Zybin, V.A.

    1988-01-01

    In this paper the different ways of development for the BN-800 maximum credible accident in case of loss and fire of primary sodium are examined. The more constraining scenario is presented. During the scenario analysis the accidental release of radioactive materials in the environment has been studied. These releases are below the authorized values [fr

  2. History of Physics as a Tool to Detect the Conceptual Difficulties Experienced by Students: The Case of Simple Electric Circuits in Primary Education

    Science.gov (United States)

    Leone, Matteo

    2014-01-01

    The present paper advocates the use of History of Science into the teaching of science in primary education through a case study in the field of electricity. In this study, which provides both historical and experimental evidence, a number of conceptual difficulties faced by early nineteenth century physicists are shown to be a useful tool to…

  3. Nano integrated circuit process

    International Nuclear Information System (INIS)

    Yoon, Yung Sup

    2004-02-01

    This book contains nine chapters, which are introduction of manufacture of semiconductor chip, oxidation such as Dry-oxidation, wet oxidation, oxidation model and oxide film, diffusion like diffusion process, diffusion equation, diffusion coefficient and diffusion system, ion implantation, including ion distribution, channeling, multiimplantation and masking and its system, sputtering such as CVD and PVD, lithography, wet etch and dry etch, interconnection and flattening like metal-silicon connection, silicide, multiple layer metal process and flattening, an integrated circuit process, including MOSFET and CMOS.

  4. Nano integrated circuit process

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Yung Sup

    2004-02-15

    This book contains nine chapters, which are introduction of manufacture of semiconductor chip, oxidation such as Dry-oxidation, wet oxidation, oxidation model and oxide film, diffusion like diffusion process, diffusion equation, diffusion coefficient and diffusion system, ion implantation, including ion distribution, channeling, multiimplantation and masking and its system, sputtering such as CVD and PVD, lithography, wet etch and dry etch, interconnection and flattening like metal-silicon connection, silicide, multiple layer metal process and flattening, an integrated circuit process, including MOSFET and CMOS.

  5. Evaluation of an optimized coolant circuit conception in a thermal whole vehicle environment with respect to the consumption of primary energy; Bewertung eines optimierten Kuehlmittelkreislaufkonzeptes in einer thermischen Gesamtfahrzeugumgebung hinsichtlich des Primaerenergieverbrauchs

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, Mirko; Neumann, Alexander; Tilch, Benjamin; Eilts, Peter [Technische Univ. Braunschweig (Germany). Inst. fuer Verbrennungskraftmaschinen; Niedersaechsisches Forschungszentrum Fahrzeugtechnik (NFF), Braunschweig (Germany)

    2012-11-01

    This work deals with a co-simulation vehicle environment developed by the institute of internal combustion engines (ivb) of the Technical University Braunschweig as a tool to analyze the thermal effects in the power train during the warm-up phase, especially on the fuel consumption. This allows evaluating new drive train concepts in early stages of development by using power train thermal management techniques (TMM). Therefore you are able to give an objective statement for these techniques by analyzing the changes in fuel consumption. The used simulation models will be introduced and the mechanical and thermal behavior is verified using test bench data. An optimized coolant circuit concept in GT Suite {sup registered}, developed at the institute is identified and coupled to a thermal engine model. In this paper, the potentials for reducing primary energy consumption in the New European Driving Cycle (NEDC) are presented. (orig.)

  6. Spatial distribution of clinical computer systems in primary care in England in 2016 and implications for primary care electronic medical record databases: a cross-sectional population study.

    Science.gov (United States)

    Kontopantelis, Evangelos; Stevens, Richard John; Helms, Peter J; Edwards, Duncan; Doran, Tim; Ashcroft, Darren M

    2018-02-28

    UK primary care databases (PCDs) are used by researchers worldwide to inform clinical practice. These databases have been primarily tied to single clinical computer systems, but little is known about the adoption of these systems by primary care practices or their geographical representativeness. We explore the spatial distribution of clinical computing systems and discuss the implications for the longevity and regional representativeness of these resources. Cross-sectional study. English primary care clinical computer systems. 7526 general practices in August 2016. Spatial mapping of family practices in England in 2016 by clinical computer system at two geographical levels, the lower Clinical Commissioning Group (CCG, 209 units) and the higher National Health Service regions (14 units). Data for practices included numbers of doctors, nurses and patients, and area deprivation. Of 7526 practices, Egton Medical Information Systems (EMIS) was used in 4199 (56%), SystmOne in 2552 (34%) and Vision in 636 (9%). Great regional variability was observed for all systems, with EMIS having a stronger presence in the West of England, London and the South; SystmOne in the East and some regions in the South; and Vision in London, the South, Greater Manchester and Birmingham. PCDs based on single clinical computer systems are geographically clustered in England. For example, Clinical Practice Research Datalink and The Health Improvement Network, the most popular primary care databases in terms of research outputs, are based on the Vision clinical computer system, used by <10% of practices and heavily concentrated in three major conurbations and the South. Researchers need to be aware of the analytical challenges posed by clustering, and barriers to accessing alternative PCDs need to be removed. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  7. Estimation of maximum pressure in small containments of PWR reactors due to loss of coolant accident in primary circuit; Estimativa da pressao maxima em contencoes de reatores PWR de pequeno porte devido a um acidente de perda de refrigerante no circuito primario

    Energy Technology Data Exchange (ETDEWEB)

    Mendes Neto, Teofilo [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Moreira, Joao Manoel Losada [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), SP (Brazil)

    2000-07-01

    This work studies the problem of containment pressurization after a LOCA in reactors with small containment free volumes. The relationship between the reactor power and the containment free volume is described with the ratio between the volumes of the primary circuit and of the containment. The maximum pressure in a containment, following a LOCA, obtained after a correlation based on large containment PWR, is around 185 psia for a primary circuit and containment volumes ratio of 0.025. For the same problem, calculations with the CONTEMPT-LT code produced a maximum pressure of 162 psia. The behavior of the temperature after a LOCA to the containment, as a function of the ratio between the primary circuit and containment volume, is such that it increases reaching asymptotically to a maximum; differently, the pressure increases almost linearly with the ratio of volumes. (author)

  8. Segmental distribution and morphometric features of primary sensory neurons projecting to the tibial periosteum in the rat.

    Directory of Open Access Journals (Sweden)

    Tadeusz Cichocki

    2004-07-01

    Full Text Available Previous reports have demonstrated very rich innervation pattern in the periosteum. Most of the periosteal fibers were found to be sensory in nature. The aim of this study was to identify the primary sensory neurons that innervate the tibial periosteum in the adult rat and to describe the morphometric features of their perikarya. To this end, an axonal fluorescent carbocyanine tracer, DiI, was injected into the periosteum on the medial surface of the tibia. The perikarya of the sensory fibers were traced back in the dorsal root ganglia (DRG L1-L6 by means of fluorescent microscopy on cryosections. DiI-containing neurons were counted in each section and their segmental distribution was determined. Using PC-assisted image analysis system, the size and shape of the traced perikarya were analyzed. DiI-labeled sensory neurons innervating the periosteum of the tibia were located in the DRG ipsilateral to the injection site, with the highest distribution in L3 and L4 (57% and 23%, respectively. The majority of the traced neurons were of small size (area < 850 microm2, which is consistent with the size distribution of CGRP- and SP-containing cells, regarded as primary sensory neurons responsible for perception of pain and temperature. A small proportion of labeled cells had large perikarya and probably supplied corpuscular sense receptors observed in the periosteum. No differences were found in the shape distribution of neurons belonging to different size classes.

  9. Electric Vehicle Interaction at the Electrical Circuit Level

    Science.gov (United States)

    2018-01-01

    The objective of the Electric Vehicle Interaction at the Electrical Circuit Level project was to investigate electric vehicle (EV) charging as a means of mitigating transient over-voltages (TOVs) on the circuit level electric utility distribution gri...

  10. Trafficking regulates the subcellular distribution of voltage-gated sodium channels in primary sensory neurons.

    Science.gov (United States)

    Bao, Lan

    2015-09-30

    Voltage-gated sodium channels (Navs) comprise at least nine pore-forming α subunits. Of these, Nav1.6, Nav1.7, Nav1.8 and Nav1.9 are the most frequently studied in primary sensory neurons located in the dorsal root ganglion and are mainly localized to the cytoplasm. A large pool of intracellular Navs raises the possibility that changes in Nav trafficking could alter channel function. The molecular mediators of Nav trafficking mainly consist of signals within the Navs themselves, interacting proteins and extracellular factors. The surface expression of Navs is achieved by escape from the endoplasmic reticulum and proteasome degradation, forward trafficking and plasma membrane anchoring, and it is also regulated by channel phosphorylation and ubiquitination in primary sensory neurons. Axonal transport and localization of Navs in afferent fibers involves the motor protein KIF5B and scaffold proteins, including contactin and PDZ domain containing 2. Localization of Nav1.6 to the nodes of Ranvier in myelinated fibers of primary sensory neurons requires node formation and the submembrane cytoskeletal protein complex. These findings inform our understanding of the molecular and cellular mechanisms underlying Nav trafficking in primary sensory neurons.

  11. Frequency and distribution of primary site among gender minority cancer patients: An analysis of U.S. national surveillance data.

    Science.gov (United States)

    Nash, Rebecca; Ward, Kevin C; Jemal, Ahmedin; Sandberg, David E; Tangpricha, Vin; Goodman, Michael

    2018-03-09

    Transgender people and persons with disorders of sex development (DSD) are two separate categories of gender minorities, each characterized by unique cancer risk factors. Although cancer registry data typically include only two categories of sex, registrars have the option of indicating that a patient is transgender or has a DSD. Data for primary cancer cases in 46 states and the District of Columbia were obtained from the North American Association of Central Cancer Registries (NAACCR) database for the period 1995-2013. The distributions of primary sites and categories of cancers with shared risk factors were examined separately for transgender and DSD patients and compared to the corresponding distributions in male and female cancer patients. Proportional incidence ratios were calculated by dividing the number of observed cases by the number of expected cases. Expected cases were calculated based on the age- and year of diagnosis-specific proportions of cases in each cancer category observed among male and female patients. Transgender patients have significantly elevated proportional incidence ratios (95% confidence intervals) for viral infection induced cancers compared to either males (2.3; 2.0-2.7) or females (3.3; 2.8-3.7). Adult DSD cancer patients have a similar distribution of primary sites compared to male or female patients but DSD children with cancer have ten times more cases of testicular malignancies than expected (95% confidence interval: 4.7-20). The proportions of certain primary sites and categories of malignancies among transgender and DSD cancer patients are different from the proportions observed for male or female patients. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. The sensitivities of in cloud and cloud top phase distributions to primary ice formation in ICON-LEM

    Science.gov (United States)

    Beydoun, H.; Karrer, M.; Tonttila, J.; Hoose, C.

    2017-12-01

    Mixed phase clouds remain a leading source of uncertainty in our attempt to quantify cloud-climate and aerosol-cloud climate interactions. Nevertheless, recent advances in parametrizing the primary ice formation process, high resolution cloud modelling, and retrievals of cloud phase distributions from satellite data offer an excellent opportunity to conduct closure studies on the sensitivity of the cloud phase to microphysical and dynamical processes. Particularly, the reliability of satellite data to resolve the phase at the top of the cloud provides a promising benchmark to compare model output to. We run large eddy simulations with the new ICOsahedral Non-hydrostatic atmosphere model (ICON) to place bounds on the sensitivity of in cloud and cloud top phase to the primary ice formation process. State of the art primary ice formation parametrizations in the form of the cumulative ice active site density ns are implemented in idealized deep convective cloud simulations. We exploit the ability of ICON-LEM to switch between a two moment microphysics scheme and the newly developed Predicted Particle Properties (P3) scheme by running our simulations in both configurations for comparison. To quantify the sensitivity of cloud phase to primary ice formation, cloud ice content is evaluated against order of magnitude changes in ns at variable convective strengths. Furthermore, we assess differences between in cloud and cloud top phase distributions as well as the potential impact of updraft velocity on the suppression of the Wegener-Bergeron-Findeisen process. The study aims to evaluate our practical understanding of primary ice formation in the context of predicting the structure and evolution of mixed phase clouds.

  13. Predicting dihedral angle probability distributions for protein coil residues from primary sequence using neural networks

    DEFF Research Database (Denmark)

    Helles, Glennie; Fonseca, Rasmus

    2009-01-01

    residue in the input-window. The trained neural network shows a significant improvement (4-68%) in predicting the most probable bin (covering a 30°×30° area of the dihedral angle space) for all amino acids in the data set compared to first order statistics. An accuracy comparable to that of secondary...... seem to have a significant influence on the dihedral angles adopted by the individual amino acids in coil segments. In this work we attempt to predict a probability distribution of these dihedral angles based on the flanking residues. While attempts to predict dihedral angles of coil segments have been...... done previously, none have, to our knowledge, presented comparable results for the probability distribution of dihedral angles. Results: In this paper we develop an artificial neural network that uses an input-window of amino acids to predict a dihedral angle probability distribution for the middle...

  14. Wireless system for location of permanent faults by short circuit current monitoring in electric power distribution network; Sistema wireless para localizacao de faltas permanentes atraves da monitoracao da corrente de curto-circuito em redes de distribuicao de energia eletrica

    Energy Technology Data Exchange (ETDEWEB)

    Machado, A.G.; Correa, A.C.; Machado, R.N. das M.; Ferreira, A.M.D.; Pinto, J.A.C. [Instituto Federal de Educacao, Ciencia e Tecnologia do Para (IFPA), Belem, PA (Brazil)], E-mail: alcidesmachado000@yahoo.com.br; Barra Junior, W. [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Inst. de Tecnologia. Faculdade de Engenharia Eletrica], E-mail: walbarra@ufpa.br

    2009-07-01

    This paper presents the development of an automatic system for permanent short-circuits location in medium voltage (13.8 kV) electric power system distribution feeders, by indirect monitoring of the line current. When a permanent failure occurs, the developed system uses mobile telephony (GSM) text messages (SMS) to inform the power company operation center where the failure most likely took place. With this information in real time, the power company operation center may provide the network restoration in a faster and efficient way. (author)

  15. Models of primary runaway electron distribution in the runaway vortex regime

    International Nuclear Information System (INIS)

    Guo, Zehua; Tang, Xian-Zhu; McDevitt, Christopher J.

    2017-01-01

    Generation of runaway electrons (RE) beams can possibly induce the most deleterious effect of tokamak disruptions. A number of recent numerical calculations have confirmed the formation of a RE bump in their energy distribution by taking into account Synchrontron radiational damping force due to RE’s gyromotions. Here, we present a detailed examination on how the bump location changes at different pitch-angle and the characteristics of the RE pitch-angle distribution. Although REs moving along the magnetic field are preferably accelerated and then populate the phase-space of larger pitch-angle mainly through diffusions, an off-axis peak can still form due to the presence of the vortex structure which causes accumulation of REs at low pitch-angle. A simplified Fokker- Planck model and its semi-analytical solutions based on local expansions around the O point is used to illustrate the characteristics of RE distribution around the O point of the runaway vortex in phase-space. The calculated energy location of the O point together with the local energy and pitch-angle distributions agree with the full numerical solution.

  16. The testing of generator circuit-breakers

    NARCIS (Netherlands)

    Smeets, R.P.P.; Linden, van der W.A.

    1998-01-01

    Generator circuit-breakers face much higher current and voltage stress than distribution switchgear. This has led to a special standard (ANSI C37.013). Strictly in accordance with this standard's requirements, test circuits and parameters for a 100 kA and 120 kA (25.3 kV) SF6 generator

  17. EFECTIVIDAD DEL MÉTODO DE FLUJO CON RECURRENCIA EN ESTUDIOS DE CIRCUITOS DE DISTRIBUCIÓN PRIMARIA; EFECTIVITY OF THE RECURRENT FLUX METHOD IN PRIMARY DISTRIBUTION STUDIES

    Directory of Open Access Journals (Sweden)

    Raúl Nicolás Carvajal Pérez

    2015-04-01

    Full Text Available Los estudios de circuitos de distribución comienzan con el cálculo de flujo de potencia por el circuito. Este refleja su estado actual en cuanto a pérdidas y caídas de tensión; básicos para cualquier análisis. Cuando se trabaja con técnicas genéticas, estos cálculos se realizan miles de veces. En este trabajo se sugiere un método de cálculo de flujo de potencia en circuitos de distribución radiales. Se aplica éste cuando solo se conoce la demanda total del circuito utilizando “Ardvinson” para asignar una “demanda de cálculo” a cada nodo. En esencia se realiza una primera iteración utilizando esa demanda y la tensión nominal del circuito en una dirección. La segunda iteración recurre a los valores obtenidos en la primera. Se exponen los cálculos realizados en un circuito real utilizando un sistema de cálculo específico y el Microsoft EXCEL para demostrar la rapidez del método y su nivel de exactitud. The first step in Distribution Circuits studios consist in power flux calculus. It shows the actual situation. of the circuit. When the studio is realized using genetic techniques, this step is repeated thousands times. A method to obtain power flux in distribution circuits is presented. The method is applied when only have the total circuit demand. Here is applied Ardvinson method to obtain “Calculus demand” in each node, realize the first iteration with these demand and nominal tension. Later, repeat the calculus using the values obtained before. An example of real circuit is resolved using specific software and EXCEL to demonstrate the efficiency of the method.

  18. Solid-state circuits

    CERN Document Server

    Pridham, G J

    2013-01-01

    Solid-State Circuits provides an introduction to the theory and practice underlying solid-state circuits, laying particular emphasis on field effect transistors and integrated circuits. Topics range from construction and characteristics of semiconductor devices to rectification and power supplies, low-frequency amplifiers, sine- and square-wave oscillators, and high-frequency effects and circuits. Black-box equivalent circuits of bipolar transistors, physical equivalent circuits of bipolar transistors, and equivalent circuits of field effect transistors are also covered. This volume is divided

  19. Circuit analysis for dummies

    CERN Document Server

    Santiago, John

    2013-01-01

    Circuits overloaded from electric circuit analysis? Many universities require that students pursuing a degree in electrical or computer engineering take an Electric Circuit Analysis course to determine who will ""make the cut"" and continue in the degree program. Circuit Analysis For Dummies will help these students to better understand electric circuit analysis by presenting the information in an effective and straightforward manner. Circuit Analysis For Dummies gives you clear-cut information about the topics covered in an electric circuit analysis courses to help

  20. Current limiter circuit system

    Science.gov (United States)

    Witcher, Joseph Brandon; Bredemann, Michael V.

    2017-09-05

    An apparatus comprising a steady state sensing circuit, a switching circuit, and a detection circuit. The steady state sensing circuit is connected to a first, a second and a third node. The first node is connected to a first device, the second node is connected to a second device, and the steady state sensing circuit causes a scaled current to flow at the third node. The scaled current is proportional to a voltage difference between the first and second node. The switching circuit limits an amount of current that flows between the first and second device. The detection circuit is connected to the third node and the switching circuit. The detection circuit monitors the scaled current at the third node and controls the switching circuit to limit the amount of the current that flows between the first and second device when the scaled current is greater than a desired level.

  1. Laser surface treatment on a nickel based alloy in order to form chromium oxide to reduce cations release in primary circuit. Experimental and numerical study of laser mater interaction

    International Nuclear Information System (INIS)

    Gouton, Lucille

    2015-01-01

    Alloy 690 (60%Ni, 30%Cr, 10%Fe) is mainly used in primary circuit pipes for nuclear power plants.The aim of this thesis is to form a Cr 2 O 3 layer, using laser surface melting, with the objective of creating a chromium-rich oxide layer. In order to optimize the treatment, it was first important to determine parameters influence on the layer oxide properties then, with the objective of a deeper understanding of mechanisms involved, to address thermo-physical phenomena occurring during and after the laser pulse striking the upper surface. A deep parametric study first enabled to find an optimized laser surface treatment which produces chromium enrichment of the upper surface and a dense and continuous oxide layer. This treatment has been applied on samples, set in a primary medium simulation loop. Experiments and calculations were carried out to provide understanding of surface chromium enrichment by laser process. The results were shown to explain chromium enrichment until melt pool solidification occurred on the upper surface, assumingly just before chromium oxide formation. This was also promoted by a high affinity with oxygen and a higher stability of Cr 2 O 3 oxide compared with other potential oxide formation. (author) [fr

  2. Estimative of core damage frequency in IPEN's IEA-R1 research reactor (PSA level 1) due to the initiating event of loss of coolant caused by large rupture in the pipe of the primary circuit

    International Nuclear Information System (INIS)

    Hirata, Daniel Massami

    2009-01-01

    This work applies the methodology of probabilistic safety assessment level 1 to the research reactor IEA-R1 IPEN-CNEN/SP. Two categories of identified initiating events of accidents in the reactor are studied: loss of flow and loss of primary coolant. Among the initiating events, blockage of flow channel and loss of cooling fluid by major pipe rupture in the primary circuit are chosen for a detailed analysis. The event tree technique is used to analyze the evolution of the accident, including the actuation or the fail of actuation of the safety systems and the reactor damages. Using the fault tree the reliability of the following reactor safety systems is evaluated: reactor shutdown system, isolation of the reactor pool, emergency core cooling system (ECCS) and the electric system. Estimative for the frequency of damage to the reactor core and the probability of failure of the analyzed systems are calculated. The estimated values for the frequencies of core damage are within the expected margins and are of the same order of magnitude as those found for similar reactors. The reliability of the reactor shutdown system, isolation of the reactor pool and ECCS are satisfactory for the conditions these systems are required. However, for the electric system it is suggested an upgrade to increase its reliability. (author)

  3. Family medicine graduate proximity to their site of training: policy options for improving the distribution of primary care access.

    Science.gov (United States)

    Fagan, Ernest Blake; Gibbons, Claire; Finnegan, Sean C; Petterson, Stephen; Peterson, Lars E; Phillips, Robert L; Bazemore, Andrew W

    2015-02-01

    The US Graduate Medical Education (GME) system is failing to produce primary care physicians in sufficient quantity or in locations where they are most needed. Decentralization of GME training has been suggested by several federal advisory boards as a means of reversing primary care maldistribution, but supporting evidence is in need of updating. We assessed the geographic relationship between family medicine GME training sites and graduate practice location. Using the 2012 American Medical Association Masterfile and American Academy of Family Physicians membership file, we obtained the percentage of family physicians in direct patient care located within 5, 25, 75, and 100 miles and within the state of their family medicine residency program (FMRP). We also analyzed the effect of time on family physician distance from training site. More than half of family physicians practice within 100 miles of their FMRP (55%) and within the same state (57%). State retention varies from 15% to 75%; the District of Columbia only retains 15% of family physician graduates, while Texas and California retain 75%. A higher percentage of recent graduates stay within 100 miles of their FMRP (63%), but this relationship degrades over time to about 51%. The majority of practicing family physicians remained proximal to their GME training site and within state. This suggests that decentralized training may be a part of the solution to uneven distribution among primary care physicians. State and federal policy-makers should prioritize funding training in or near areas with poor access to primary care services.

  4. Evaluation of tests for coastdown of reactor coolant flow and measure of primary circuit flow of Angra-1 nuclear power plant

    International Nuclear Information System (INIS)

    Galetti, M.R.S.; Camargo, C.T.M.; Pontedeiro, A.C.

    1987-05-01

    The Angra 1 Nuclear Power Plant first reload license was issued after several technical discussions among CNEN, FURNAS and KWU. During the license process CNEN has established that the plant could return to anormal operation if the requirements described in the letter CNEN-DExL-C 06/86 were satisfied. The requirements according to the CNEN Transient and Thermohydraulic Group Analysis were to do again the following tests: 'Primary Flow Measurement' to check if the excess flow measured in the first cycle was held; and Pump Coastdown' to check if the Westinghouse and KWU fuel elements are thermo-hydraulicaly compatibles during transients. The mixed core must keep at least the same safety margin presented on Angra 1 FSAR for the original core. The tests and the analysis of results are described. (Author) [pt

  5. Structural and Functional Substitution of Deleted Primary Sensory Neurons by New Growth from Intrinsic Spinal Cord Nerve Cells: An Alternative Concept in Reconstruction of Spinal Cord Circuits

    Directory of Open Access Journals (Sweden)

    Nicholas D. James

    2017-07-01

    Full Text Available In a recent clinical report, return of the tendon stretch reflex was demonstrated after spinal cord surgery in a case of total traumatic brachial plexus avulsion injury. Peripheral nerve grafts had been implanted into the spinal cord to reconnect to the peripheral nerves for motor and sensory function. The dorsal root ganglia (DRG containing the primary sensory nerve cells had been surgically removed in order for secondary or spinal cord sensory neurons to extend into the periphery and replace the deleted DRG neurons. The present experimental study uses a rat injury model first to corroborate the clinical finding of a re-established spinal reflex arch, and second, to elucidate some of the potential mechanisms underlying these findings by means of morphological, immunohistochemical, and electrophysiological assessments. Our findings indicate that, after spinal cord surgery, the central nervous system sensory system could replace the traumatically detached original peripheral sensory connections through new neurite growth from dendrites.

  6. SOLPREC - a code for estimating the deposition density of activated corrosion products in the primary circuits of LMFBR: development, validation and application

    International Nuclear Information System (INIS)

    Sivasubramanian, K.; Satyanarayana, S.V.; Mohankumar, N.

    2002-01-01

    Full text: During the normal operation of a liquid metal fast breeder reactor, activated corrosion products are produced in stainless steel, which is the structural material of the core. The products consisting mainly of 54 Mn and 60 Co diffuse through the cladding into the primary sodium and get deposited along the pipelines of the reactor vessel. Since this poses a radiation hazard, an estimate of this build up is essential. Using the solution and precipitation model of Polley and Skyrme, a one-dimensional code to estimate the surface and bulk concentrations was developed for the fast breeder test reactor at Kalpakkam. This paper gives an outline of this code and the relevant results

  7. Influence of undersized cementless hip stems on primary stability and strain distribution.

    Science.gov (United States)

    Fottner, Andreas; Woiczinski, Matthias; Kistler, Manuel; Schröder, Christian; Schmidutz, Tobias F; Jansson, Volkmar; Schmidutz, Florian

    2017-10-01

    Undersizing of cementless hip stems is a risk factor for aseptic loosening and early subsidence. The purpose of this study was to evaluate the effects of undersized stems and determine whether a biomechanical study can predict the clinical results. Three consecutive sizes of a clinically proven stem (CLS Spotorno) were implanted into six composite femora (size large, Sawbones ® ), respectively. According to the Canal Fill Index (CFI), two stems (size 11.25 and 12.5) were undersized (CFI  80%). The primary stability was evaluated by measurement of 3-dimensional (3D)-micromotions under physiological adapted load and surface strains were recorded before and after implantation to detect stress-shielding processes. Both undersized stems revealed significantly higher micromotions in all regions compared to the appropriate stem. The highest micromotions were registered at the distal tip of the three stem sizes. The changes in surface strain did not show a significant difference between the three stem sizes, but the highest strain reduction was observed proximally indicating a tendency for stress shielding. This study confirms the clinical assumption that undersized stem result in a significantly reduced primary stability. Furthermore, in vitro studies allow to determine the effects of undersizing and stress shielding processes.

  8. Distribution of Porphyromonas gingivalis fimA genotypes in primary endodontic infections.

    Science.gov (United States)

    Rôças, Isabela N; Siqueira, José F

    2010-03-01

    Long fimbriae (FimA) are important virulence factors of Porphyromonas gingivalis. Based on the diversity of the fimA gene, this species is classified into 6 genotypes. This study surveyed samples from primary endodontic infections for the presence of these P. gingivalis fimA variants. Genomic DNA isolated from samples taken from 25 root canals of teeth with chronic apical periodontitis and 25 aspirates from acute apical abscess was used as template in polymerase chain reaction (PCR) assays directed toward the detection of the different P. gingivalis fimA genotypes. Porphyromonas gingivalis was detected by a 16S rRNA gene-based PCR in 36% of the total number of cases sampled (44% of chronic apical periodontitis and 28% of abscess aspirates). In cases of chronic apical periodontitis, P. gingivalis variant type IV was the most prevalent (24%), followed by types I (20%), II (16%), and III (8%). In acute abscess samples, variant type II was the most prevalent (12%), followed by types III and IV (8% of each) and type I (4%). Combinations of up to 3 different genotypes were detected in a few cases. No single fimA genotype variant or combination thereof was significantly associated with symptoms. Overall, fimA types IV (16%), II (14%), and I (12%) were the most prevalent. Findings demonstrated that different P. gingivalis fimA genotypes can be present in primary endodontic infections. Copyright 2010 Mosby, Inc. All rights reserved.

  9. Homeostatic migration and distribution of innate immune cells in primary and secondary lymphoid organs with ageing.

    Science.gov (United States)

    Nikolich-Žugich, J; Davies, J S

    2017-03-01

    Ageing of the innate and adaptive immune system, collectively termed immune senescence, is a complex process. One method to understand the components of ageing involves dissociating the effects of ageing on the cells of the immune system, on the microenvironment in lymphoid organs and tissues where immune cells reside and on the circulating factors that interact with both immune cells and their microenvironment. Heterochronic parabiosis, a surgical union of two organisms of disparate ages, is ideal for this type of study, as it has the power to dissociate the age of the cell and the age of the microenvironment into which the cell resides or is migrating. So far, however, it has been used sparingly to study immune ageing. Here we review the limited literature on homeostatic innate immune cell trafficking in ageing in the absence of chronic inflammation. We also review our own recent data on trafficking of innate immune subsets between primary and secondary lymphoid organs in heterochronic parabiosis. We found no systemic bias in retention or acceptance of neutrophils, macrophages, dendritic cells or natural killer cells with ageing in primary and secondary lymphoid organs. We conclude that these four innate immune cell types migrate to and populate lymphoid organs (peripheral lymph nodes, spleen and bone marrow), regardless of their own age and of the age of lymphoid organs. © 2017 British Society for Immunology.

  10. Study on a corrosion products behavior with zinc injection in PWR primary circuit based on the crud investigation in actual plant

    International Nuclear Information System (INIS)

    Hisamune Kenji; Nambu Tohru; Akutagawa Daisuke; Nagata Nobuaki; Shimizu, Yuichi; Nagamine, Kunitaka; Kogawa Noritaka

    2012-09-01

    Zinc injection into the reactor coolant of Pressurized Water Reactor (PWR) is one of the most effective techniques for removing radioactive cobalt from the chromite type spinel oxides in the inner layer of reactor coolant component surfaces. Many documents have reported that zinc injection applied plants have generally achieved positive dose rate reduction effects for the reactor coolant components and piping. Tsuruga Nuclear Power Plant unit 2 (hereafter Tsuruga unit 2) which applied zinc injection in 2005 has also achieved good dose reduction effects in most primary coolant piping. However, some piping without dose-rate reduction effects exist, it has come to an issue to plan radiation exposure reduction measures for the works around relevant piping. To plan a reasonable dose-rate reduction measures for respective components and piping in primary systems, it is considered necessary to understand the dose-rate reduction effects of zinc injection mechanically. Therefore, the surface oxides/deposits on piping and fuel cladding tubes with operational histories under zinc injection were investigated. As a result of the investigation, the changes in specific aspects of oxide layers and CRUDs are found as follow: - Owing to long-term zinc injection, deposits and oxides on the primary coolant piping are extremely reduced, the boundary between the outer oxide layer and the inner oxide layer become unclear with the thinning of the outer oxide layers. - At a Pressurizer Spray Piping, the dose-rate increases than before zinc injection. The oxide layers have the same 3-layer construction as before zinc injection, and the surface concentration of the radioactive cobalt is high. - At the fuel cladding tube surfaces, what is observed is the amount of metal nickel decrease and the chromium composition increase in the spinel type oxide From these results, it is suggested that, the oxide layers composed principally of zinc chromite spinel grow up on the pipe surface with zinc

  11. Development of a kinetic model, including rate constant estimations, on iodine and caesium behaviour in the primary circuit of LWR's under accident conditions

    International Nuclear Information System (INIS)

    Alonso, A.; Buron, J.M.; Fernandez, S.

    1991-07-01

    In this report, a kinetic model has been developed with the aim to try to reproduce the chemical phenomena that take place in a flowing system containing steam, hydrogen and iodine and caesium vapours. The work is divided into two different parts. The first part consists in the estimation, through the Activited Complex Theory, of the reaction rate constants, for the chosen reactions, and the development of the kinetic model based on the concept of ideal tubular chemical reactor. The second part deals with the application of such model to several cases, which were taken from the Phase B 'Scoping Calculations' of the Phebus-FP Project (sequence AB) and the SFD-ST and SFD1.1 experiments. The main conclusion obtained from this work is that the assumption of instantaneous equilibrium could be inacurrate in order to estimate the iodine and caesium species distribution under severe accidents conditions

  12. Effect of Local Strain Distribution of Cold-Rolled Alloy 690 on Primary Water Stress Corrosion Crack Growth Behavior

    Directory of Open Access Journals (Sweden)

    Kim S.-W.

    2017-06-01

    Full Text Available This work aims to study the stress corrosion crack growth behavior of cold-rolled Alloy 690 in the primary water of a pressurized water reactor. Compared with Alloy 600, which shows typical intergranular cracking along high angle grain boundaries, the cold-rolled Alloy 690, with its heterogeneous microstructure, revealed an abnormal crack growth behavior in mixed mode, that is, in transgranular cracking near a banded region, and in intergranular cracking in a matrix region. From local strain distribution analysis based on local mis-orientation, measured along the crack path using the electron back scattered diffraction method, it was suggested that the abnormal behavior was attributable to a heterogeneity of local strain distribution. In the cold-rolled Alloy 690, the stress corrosion crack grew through a highly strained area formed by a prior cold-rolling process in a direction perpendicular to the maximum principal stress applied during a subsequent stress corrosion cracking test.

  13. Distribution of TTX-sensitive voltage-gated sodium channels in primary sensory endings of mammalian muscle spindles.

    Science.gov (United States)

    Carrasco, Dario I; Vincent, Jacob A; Cope, Timothy C

    2017-04-01

    Knowledge of the molecular mechanisms underlying signaling of mechanical stimuli by muscle spindles remains incomplete. In particular, the ionic conductances that sustain tonic firing during static muscle stretch are unknown. We hypothesized that tonic firing by spindle afferents depends on sodium persistent inward current (INaP) and tested for the necessary presence of the appropriate voltage-gated sodium (NaV) channels in primary sensory endings. The NaV 1.6 isoform was selected for both its capacity to produce INaP and for its presence in other mechanosensors that fire tonically. The present study shows that NaV 1.6 immunoreactivity (IR) is concentrated in heminodes, presumably where tonic firing is generated, and we were surprised to find NaV 1.6 IR strongly expressed also in the sensory terminals, where mechanotransduction occurs. This spatial pattern of NaV 1.6 IR distribution was consistent for three mammalian species (rat, cat, and mouse), as was tonic firing by primary spindle afferents. These findings meet some of the conditions needed to establish participation of INaP in tonic firing by primary sensory endings. The study was extended to two additional NaV isoforms, selected for their sensitivity to TTX, excluding TTX-resistant NaV channels, which alone are insufficient to support firing by primary spindle endings. Positive immunoreactivity was found for NaV 1.1 , predominantly in sensory terminals together with NaV 1.6 and for NaV 1.7 , mainly in preterminal axons. Differential distribution in primary sensory endings suggests specialized roles for these three NaV isoforms in the process of mechanosensory signaling by muscle spindles. NEW & NOTEWORTHY The molecular mechanisms underlying mechanosensory signaling responsible for proprioceptive functions are not completely elucidated. This study provides the first evidence that voltage-gated sodium channels (NaVs) are expressed in the spindle primary sensory ending, where NaVs are found at every site

  14. Chemical and radiochemical control of the primary circuit of Atucha INPP (Nuclear Power Plant) since the start up in January 1990

    International Nuclear Information System (INIS)

    Ali, S.P; Baungartner, E.C.; Blesa, M.A.

    1990-01-01

    Since the start up of Atucha I Nuclear Power Plant in January 1990, an exhaustive chemical and radiochemical control of primary media was undertaken. The main objectives were the evaluation of the water condition after the long outage and the determination of activity measurements limitations to detect and localize fuel failures. Chemical and radiochemical techniques were critically proved. At the same time, a complete program of updating and optimization of those procedures was developed, including the revision of the analytical parameters, range of applicability and accuracy. A more adequate processing of data was adopted. They were compared with historical values corresponding to periods with and without fuel elements failures, used as references. The analysis of theoretical models of total gamma activity concentration and some specific radionuclides activity concentration evolution and their rates, and the comparison with experimental data obtained during normal operation including some failure events, generated tables of alarm criteria through a combination of parameters. Additionally, actions are suggested for different combination of parameters. Operative conditions that might interfere in the detection and localization of a failed fuel element are also pointed out. (Author)

  15. Determination of safety margins for creep loaded primary circuit components in case of loss of pressure accidents of a HTR plant (SR 383)

    International Nuclear Information System (INIS)

    Breitbach, G.; Ahmed, K.; Over, H.; Schubert, F.; Nickel, H.

    1991-10-01

    The wall thickness of tubes in high temperature plants must be limited in such a way that pressure differences can not produce unadmissible deformations. For HTR (PNP-Plant) the postulated loss of secondary pressure is one of the considered accidents. In that case the tubes of the heat exchangers are loaded by the outher pressure of the primary coolant. So the risk of a creep collapse is given. The report is related to experimental and theoretical work for the creep collapse phenomena. HTR relevant tube geometries of the high temperature alloys NiCr22Co12Mo (INCONEL 617) and X10NiCrAlTi 32 20 (INCOLOY 800) were tested at temperatures of 900 and 950deg C and outer pressure loads in the range 40 bars. The experimental results are compared with theoretically computed values and discussed. The problem of safety margin is treated. Further, simplified procedures are developed for the estimation of the collapse time. (orig.) [de

  16. Distribution and etiology of chronic respiratory diseases in primary healthcare departments in Cape Verde.

    Science.gov (United States)

    Carreiro-Martins, P; Rosado-Pinto, J; do Céu Teixeira, M; Neuparth, N; Silva, O; Papoila, A L; Khaltaev, N; Bousquet, J; Annesi-Maesano, I

    2015-10-01

    Data on chronic respiratory diseases (CRD) are scarce or unavailable in most African countries. We aimed to determine the prevalence of CRD and associated risk factors in Cape Verde, at the primary healthcare level. In the frame of the Global Alliance Against Chronic Respiratory Diseases, a cross-sectional study was carried out in October 2006 in 3256 outpatients (2142 women) (median age of 30 years) seeking care at primary healthcare departments, through a standardized interview questionnaire during two weeks. The prevalence of emphysema, tuberculosis, chronic bronchitis, rhinoconjunctivitis and asthma were 0.7%, 2%, 4.5%, 12.3% and 6.2%, respectively. Current smoking was associated with emphysema (OR: 3.36; 95% CI: 0.97-11.40) and tuberculosis (OR: 2.14; 95% CI: 1.07-4.30), ever exposed to a dusty workplace with chronic bronchitis (OR: 2.20; CI 95%: 1.50-3.21) and rhinoconjunctivitis (OR: 1.56; CI 95%: 1.23-1.98) and cooking or heating using an open fire with asthma (OR: 1.59; CI 95%: 1.16-2.19). The estimates of attributable risks percent indicated that, in the sample, a noticeable part of CRD could be attributed to active smoking, exposure to dust and biomass. Results varied according to gender, particularly regarding current smoking which was more important for men. Tobacco smoking, exposure to dust at work and using an open fire were important risk factors for CRD. Our results suggest that if actions were taken in order to reduce the aforementioned exposures, an important CRD decrease could be achieved. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  17. One size does not fit all: The impact of primary vaccine container size on vaccine distribution and delivery.

    Science.gov (United States)

    Haidari, Leila A; Wahl, Brian; Brown, Shawn T; Privor-Dumm, Lois; Wallman-Stokes, Cecily; Gorham, Katie; Connor, Diana L; Wateska, Angela R; Schreiber, Benjamin; Dicko, Hamadou; Jaillard, Philippe; Avella, Melanie; Lee, Bruce Y

    2015-06-22

    While the size and type of a vaccine container (i.e., primary container) can have many implications on the safety and convenience of a vaccination session, another important but potentially overlooked consideration is how the design of the primary container may affect the distribution of the vaccine, its resulting cost, and whether the vial is ultimately opened. Using our HERMES software platform, we developed a simulation model of the World Health Organization Expanded Program on Immunization supply chain for the Republic of Benin and used the model to explore the effects of different primary containers for various vaccine antigens. Replacing vaccines with presentations containing fewer doses per vial reduced vaccine availability (proportion of people arriving for vaccines who are successfully immunized) by as much as 13% (from 73% at baseline) and raised logistics costs by up to $0.06 per dose administered (from $0.25 at baseline) due to increased bottlenecks, while reducing total costs by as much as $0.15 per dose administered (from $2.52 at baseline) due to lower open vial wastage. Primary containers with a greater number of doses per vial each improved vaccine availability by 19% and reduced logistics costs by $0.05 per dose administered, while reducing the total costs by up to $0.25 per dose administered. Changes in supply chain performance were more extreme in departments with greater constraints. Implementing a vial opening threshold reversed the direction of many of these effects. Our results show that one size may not fit all when choosing a primary vaccine container. Rather, the choice depends on characteristics of the vaccine, the vaccine supply chain, immunization session size, and goals of decision makers. In fact, the optimal vial size may vary among locations within a country. Simulation modeling can help identify tailored approaches to improve availability and efficiency. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Distribution of liver metastases based on the site of primary pancreatic carcinoma

    International Nuclear Information System (INIS)

    Ambrosetti, Maria Chiara; Zamboni, Giulia A.; Mucelli, Roberto Pozzi

    2016-01-01

    To investigate whether the different location of pancreatic adenocarcinoma affects the lobar distribution of metastases to the liver. From all patients who underwent multidetector computed tomography (MDCT) examinations for staging of pancreatic adenocarcinoma in the last 4 years we selected 80 patients (42 men, 38 women; mean age, 60.56 years) with liver metastases and a pancreatic adenocarcinoma of the head (group A, 40 patients; diameter, 32.41 ± 2.28 mm) or body-tail (group B, 40 patients; diameter, 52.21 ± 2.8 mm). We analysed tumour site, diameter, vascular invasion and number of metastases in each lobe of the liver. The total number of metastases was compared between the two groups with an unpaired t-test, while Fisher's test was used to compare the number of metastases within the two lobes. As expected, the number of liver metastases was higher in group B than in group A. The ratio of metastases in the right-to-left hemi-liver was 7.4:1 for group A compared with 3.3:1 for group B (p < 0.0001). Although the number of liver metastases is higher in the right lobe than in the left lobe in both groups, there is a significant difference in the ratio of metastases between the right and the left hemi-liver. This supports the existence of a streamline phenomenon and a selective lobar distribution of metastases within the liver. (orig.)

  19. Distributed leadership - Strenghtening the condition for continious innovation in primary health organizations

    DEFF Research Database (Denmark)

    Günzel-Jensen, Franziska; Ulhøi, John Parm

    on distributed leadership as a means to influence resource availability, decision making and goal setting in an organizational setting. The overall RQ guiding this research is: how does DL need to be enacted to enable change and continuous innovation in healthcare. We first introduce a theory developing case...... study of four units within a Danish hospital with about 4500 employees. Our findings identify a mix of emergent and contextualized leadership which needs time to be enacted. Furthermore, we find that resource allocation, social capital accumulation, collaborative work culture, and legitimacy building......Public hospitals need to change and innovate to handle the challenges of increasing demands for more, faster, better and cheaper health provision. Practicing leadership does not occur in a sterile context but in a highly contextual and social setting. This in turn invites for focussing...

  20. Engineering Inertial and Primary-Frequency Response for Distributed Energy Resources: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Dall-Anese, Emiliano [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhao, Changhong [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Guggilam, Swaroop [University of Minnesota; Dhople, Sairaj V [University of Minnesota; Chen, Yu C [University of British Columbia; Zhao, Changhong [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-12-19

    We propose a framework to engineer synthetic-inertia and droop-control parameters for distributed energy resources (DERs) so that the system frequency in a network composed of DERs and synchronous generators conforms to prescribed transient and steady-state performance specifications. Our approach is grounded in a second-order lumped-parameter model that captures the dynamics of synchronous generators and frequency-responsive DERs endowed with inertial and droop control. A key feature of this reduced-order model is that its parameters can be related to those of the originating higher-order dynamical model. This allows one to systematically design the DER inertial and droop-control coefficients leveraging classical frequency-domain response characteristics of second-order systems. Time-domain simulations validate the accuracy of the model-reduction method and demonstrate how DER controllers can be designed to meet steady-state-regulation and transient-performance specifications.

  1. Leak detection system with distributed microprocessor in the primary containment vessel

    International Nuclear Information System (INIS)

    Inahara, K.; Yoshioka, K.; Tomizawa, T.

    1980-01-01

    Responding to the demand for greater improvements of the safety monitoring system, less public radiation exposure, and increase of plant availability, measuring and control systems in nuclear power plants have undergone many improvements. Leak detection systems are also required to give earlier warning, additional accuracy, and continuous monitoring function. This paper describes the drywell sump leakage detection system utilizing a distributed microprocessor, which is a successful application owing to its versatile function and ease of installation. The microprocessor performs various functions such as a rate of level change computation, conversion to leakage flow rate, initiation of alarm, and sump pump control. This system has already been applied to three operating BWR plants that demonstrate its efficiency. (auth)

  2. Intuitive analog circuit design

    CERN Document Server

    Thompson, Marc

    2013-01-01

    Intuitive Analog Circuit Design outlines ways of thinking about analog circuits and systems that let you develop a feel for what a good, working analog circuit design should be. This book reflects author Marc Thompson's 30 years of experience designing analog and power electronics circuits and teaching graduate-level analog circuit design, and is the ideal reference for anyone who needs a straightforward introduction to the subject. In this book, Dr. Thompson describes intuitive and ""back-of-the-envelope"" techniques for designing and analyzing analog circuits, including transistor amplifi

  3. The circuit designer's companion

    CERN Document Server

    Williams, Tim

    1991-01-01

    The Circuit Designer's Companion covers the theoretical aspects and practices in analogue and digital circuit design. Electronic circuit design involves designing a circuit that will fulfill its specified function and designing the same circuit so that every production model of it will fulfill its specified function, and no other undesired and unspecified function.This book is composed of nine chapters and starts with a review of the concept of grounding, wiring, and printed circuits. The subsequent chapters deal with the passive and active components of circuitry design. These topics are foll

  4. Electronic devices and circuits

    CERN Document Server

    Pridham, Gordon John

    1972-01-01

    Electronic Devices and Circuits, Volume 3 provides a comprehensive account on electronic devices and circuits and includes introductory network theory and physics. The physics of semiconductor devices is described, along with field effect transistors, small-signal equivalent circuits of bipolar transistors, and integrated circuits. Linear and non-linear circuits as well as logic circuits are also considered. This volume is comprised of 12 chapters and begins with an analysis of the use of Laplace transforms for analysis of filter networks, followed by a discussion on the physical properties of

  5. Distribution of phototrophic populations and primary production in a microbial mat from the Ebro Delta, Spain.

    Science.gov (United States)

    Martínez-Alonso, Maira; Mir, Joan; Caumette, Pierre; Gaju, Núria; Guerrero, Ricardo; Esteve, Isabel

    2004-03-01

    Microbial mats arising in the sand flats of the Ebro Delta (Tarragona, Spain) were investigated during the summer season, when the community was highly developed. These mats are composed of three pigmented layers of phototrophic organisms, an upper brown layer mainly composed of Lyngbya aestuarii and diatoms, an intermediate green layer of the cyanobacterium Microcoleus chthonoplastes, and an underlying pink layer of a so-far unidentified purple sulfur bacterium. In the photic zone, oxygenic phototrophs constitute about 58% of total photosynthetic biomass, measured as biovolume, and anoxygenic phototrophs represent 42%. Diatoms constitute 11.8% of the oxygenic biomass, M. chthonoplastes 61.2%, and L. aestuarii and coccoid cyanobacteria 20.6 and 6.4%, respectively. In this laminated community, organic matter has an autochthonous origin, and photosynthesis is the most important source of organic carbon. Oxygen production reaches up to 27.2 mmol O(2) m(-2) h(-1), measured at 1000 microE m(-2) s(-1) light intensity, whereas oxidation of sulfide in the light has been calculated to be 18.6 mmol S m(-2) h(-1). This amount represents 26% of the total photosynthetic production in terms of photoassimilated carbon, demonstrating the important role of anoxygenic phototrophs as primary producers in the pink layer of Ebro Delta microbial mats.

  6. Influence of primary fragment excitation energy and spin distributions on fission observables

    Science.gov (United States)

    Litaize, Olivier; Thulliez, Loïc; Serot, Olivier; Chebboubi, Abdelaziz; Tamagno, Pierre

    2018-03-01

    Fission observables in the case of 252Cf(sf) are investigated by exploring several models involved in the excitation energy sharing and spin-parity assignment between primary fission fragments. In a first step the parameters used in the FIFRELIN Monte Carlo code "reference route" are presented: two parameters for the mass dependent temperature ratio law and two constant spin cut-off parameters for light and heavy fragment groups respectively. These parameters determine the initial fragment entry zone in excitation energy and spin-parity (E*, Jπ). They are chosen to reproduce the light and heavy average prompt neutron multiplicities. When these target observables are achieved all other fission observables can be predicted. We show here the influence of input parameters on the saw-tooth curve and we discuss the influence of a mass and energy-dependent spin cut-off model on gamma-rays related fission observables. The part of the model involving level densities, neutron transmission coefficients or photon strength functions remains unchanged.

  7. A Didatic Reflection on Distribution of Textual Genres to the Primary School

    Directory of Open Access Journals (Sweden)

    João Bosco Figueiredo-Gomes

    2015-12-01

    Full Text Available Considering the interest on the studies about textual genre and its teaching in the three last decades, the present article presents a report of an analysis of collection of didactic books of Portuguese language of the Primary School II, which aimed at verifying if the didactic book enables a comprehension about different textual genres as for the student, in relation to the context and social use, as well as for the teacher, in relation to parameters in order to do an analysis and choice of didactic collection books. The theoretical methodological framework based mainly in the contributions of Interactionism Socio-discursive: Bronckart (1999, 2003 and Schneuwly and Dolz (2004; in the studies by Marcuschi (2002, 2008 and in the orientations about the teaching of mother language contained in the National Curriculum Guidelines – PCN (BRASIL, 1998. The results provided a reflection that offers param-eters to the analysis, choice and organization of didactic collections, as well as suggestions of pedagogic implementation towards the teaching of Portuguese language.

  8. Distribution of Biopsy-Proven Presumed Primary Glomerulonephropathies in 2000-2011 Among a Racially and Ethnically Diverse US Population.

    Science.gov (United States)

    Sim, John J; Batech, Michael; Hever, Aviv; Harrison, Teresa N; Avelar, Taurino; Kanter, Michael H; Jacobsen, Steven J

    2016-10-01

    The incidence and distribution of primary glomerulonephropathies vary throughout the world and by race and ethnicity. We sought to evaluate the distribution of primary glomerulonephropathies among a large racially and ethnically diverse population of the United States. Case series from January 1, 2000, through December 31, 2011. Adults (aged ≥ 18 years) of an integrated health system who underwent native kidney biopsy and had kidney biopsy findings demonstrating focal segmental glomerulosclerosis (FSGS), membranous glomerulonephritis (MGN), minimal change disease (MCD), immunoglobulin A nephropathy (IgAN), and other. Rates and characteristics of the most common primary glomerulonephropathies overall and by race and ethnicity. 2,501 patients with primary glomerulonephropathy were identified, with a mean age 50.6 years, 45.7% women, 36.1% Hispanics, 31.2% non-Hispanic whites, 17.4% blacks, and 12.4% Asians. FSGS was the most common glomerulonephropathy (38.9%) across all race and ethnic groups, followed by MGN (12.7%), MCD (11.0%), IgAN (10.2%), and other (27.3%). The FSGS category had the greatest proportion of blacks, and patients with FSGS had the highest rate of poverty. IgAN was the second most common glomerulonephropathy among Asians (28.6%), whereas it was 1.2% among blacks. Patients with MGN presented with the highest proteinuria (protein excretion, 8.3g) whereas patients with FSGS had the highest creatinine levels (2.6mg/dL). Overall glomerulonephropathy rates increased annually in our 12-year observation period, driven by FSGS (2.7 cases/100,000) and IgAN (0.7 cases/100,000). MGN and MCD rates remained flat. Missing data for urine albumin and sediment, indication bias in performing kidney biopsies, and inexact classification of primary versus secondary disease. Among a racially and ethnically diverse cohort from a single geographical area and similar environment, FSGS was the most common glomerulonephropathy, but there was variability of other

  9. Monitoring Sodium Circuits and ACSR cables using Fiber Optic Sensors

    International Nuclear Information System (INIS)

    Kasinathan, M.; Sosamma, S.; Babu-Rao, C.; Kumar, Anish; Purna-Chandra-Rao, B.; Murali, N; Jayakumar, T.

    2013-06-01

    Raman Distributed Temperature Sensors (RDTS) are attractive for the monitoring of coolant loop systems in nuclear power plants and monitoring of overhead power transmission lines. This paper discusses deployment of RDTS on double walled pipelines of primary sodium circuits in Fast Breeder Reactors (FBR). It is demonstrated as a proof-of-concept on a test loop with water as the leaking medium. Path delay multiplexing is adopted to improve the spatial resolution from 1.02 m to 0.5 m. A second application focuses on the influence of environmental factors on the detectability of defects in the ACSR cables using RDTS. (authors)

  10. 30 CFR 56.6402 - Deenergized circuits near detonators.

    Science.gov (United States)

    2010-07-01

    ... Electric Blasting § 56.6402 Deenergized circuits near detonators. Electrical distribution circuits within 50 feet of electric detonators at the blast site shall be deenergized. Such circuits need not be deenergized between 25 to 50 feet of the electric detonators if stray current tests, conducted as frequently...

  11. 30 CFR 57.6402 - Deenergized circuits near detonators.

    Science.gov (United States)

    2010-07-01

    ... Electric Blasting-Surface and Underground § 57.6402 Deenergized circuits near detonators. Electrical distribution circuits within 50 feet of electric detonators at the blast site shall be deenergized. Such circuits need not be deenergized between 25 to 50 feet of the electric detonators if stray current tests...

  12. Methods and theory in bone modeling drift: comparing spatial analyses of primary bone distributions in the human humerus.

    Science.gov (United States)

    Maggiano, Corey M; Maggiano, Isabel S; Tiesler, Vera G; Chi-Keb, Julio R; Stout, Sam D

    2016-01-01

    This study compares two novel methods quantifying bone shaft tissue distributions, and relates observations on human humeral growth patterns for applications in anthropological and anatomical research. Microstructural variation in compact bone occurs due to developmental and mechanically adaptive circumstances that are 'recorded' by forming bone and are important for interpretations of growth, health, physical activity, adaptation, and identity in the past and present. Those interpretations hinge on a detailed understanding of the modeling process by which bones achieve their diametric shape, diaphyseal curvature, and general position relative to other elements. Bone modeling is a complex aspect of growth, potentially causing the shaft to drift transversely through formation and resorption on opposing cortices. Unfortunately, the specifics of modeling drift are largely unknown for most skeletal elements. Moreover, bone modeling has seen little quantitative methodological development compared with secondary bone processes, such as intracortical remodeling. The techniques proposed here, starburst point-count and 45° cross-polarization hand-drawn histomorphometry, permit the statistical and populational analysis of human primary tissue distributions and provide similar results despite being suitable for different applications. This analysis of a pooled archaeological and modern skeletal sample confirms the importance of extreme asymmetry in bone modeling as a major determinant of microstructural variation in diaphyses. Specifically, humeral drift is posteromedial in the human humerus, accompanied by a significant rotational trend. In general, results encourage the usage of endocortical primary bone distributions as an indicator and summary of bone modeling drift, enabling quantitative analysis by direction and proportion in other elements and populations. © 2015 Anatomical Society.

  13. Anatomic Subsite of Primary Colorectal Cancer and Subsequent Risk and Distribution of Second Cancers

    Science.gov (United States)

    Phipps, Amanda I.; Chan, Andrew T.; Shuji Ogino, MD

    2013-01-01

    Background Individuals with a history of colorectal cancer (CRC) have an increased risk of subsequent cancer. We used cancer registry data to evaluate whether this increased risk of cancer after CRC differed by anatomic subsite of a first CRC. Methods Individuals diagnosed with first primary CRC between 1992–2009 were identified from 12 Surveillance Epidemiology and End Results (SEER) cancer registries. We calculated standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) comparing the incidence of subsequent cancers in these index CRC cases to cancer incidence rates in the general population. SIRs were calculated for cancers at anatomic sites within and outside the colorectum in analyses stratified by subsite of the index CRC. Results Cancer incidence rates were significantly higher in those with prior CRC than in the general population (SIR=1.15, 95% CI: 1.13–1.16). Individuals with an index CRC located between the transverse and descending colon experienced the greatest increased risk both overall (SIR=1.29 to 1.33), and with respect to risk of second CRC in particular (SIR=2.53 to 3.35). Incidence of small intestinal cancer was significantly elevated regardless of index CRC subsite (SIR=4.31, 95% CI: 3.70–4.77); incidence of endometrial cancer was elevated in those with index CRC in the proximal colon (SIR=1.37 to 1.79). Conclusions Risk of second cancer after CRC differs by anatomic site of the first tumor, and is particularly pronounced for those with prior CRC located in the transverse to descending colon. The mechanisms underlying this pattern of second cancer risk remain unknown. PMID:23856984

  14. Distribution and morphology of nitridergic neurons across functional domains of the rat primary somatosensory cortex

    Directory of Open Access Journals (Sweden)

    Anaelli A Nogueira-Campos

    2012-11-01

    Full Text Available The rat primary somatosensory cortex (S1 is remarkable for its conspicuous vertical compartmentalization in barrels and septal columns, which are additionally stratified in horizontal layers. Whereas excitatory neurons from each of these compartments perform different types of processing, the role of interneurons is much less clear. Among the numerous types of GABAergic interneurons, those producing nitric oxide (NO are especially puzzling, since this gaseous messenger can modulate neural activity, synaptic plasticity and neurovascular coupling. We used a quantitative morphological approach to investigate whether nitrergic interneurons, which might therefore be considered both as NO volume diffusers and as elements of local circuitry, display features that could relate to barrel cortex architecture. In fixed brain sections, nitrergic interneurons can be revealed by histochemical processing for NADPH-diaphorase (NADPHd. Here, the dendritic arbors of nitrergic neurons from different compartments of area S1 were 3D reconstructed from serial 200-μm thick sections, using 100x objective and the Neurolucida system. Standard morphological parameters were extracted for all individual arbors and compared across columns and layers. Wedge analysis was used to compute dendritic orientation indices. Supragranular layers displayed the highest density of nitrergic neurons, whereas layer IV contained nitrergic neurons with largest soma area. The highest nitrergic neuronal density was found in septa, where dendrites were previously characterized as more extense and ramified than in barrels. Dendritic arbors were not confined to the boundaries of the column nor layer of their respective soma, being mostly double-tufted and vertically oriented, except in supragranular layers. These data strongly suggest that nitrergic interneurons adapt their morphology to the dynamics of processing performed by cortical compartments.

  15. Changes in the state-level distribution of primary and secondary syphilis in the USA, 1985-2007.

    Science.gov (United States)

    Chesson, Harrell W; Sternberg, Maya; Leichliter, Jami S; Aral, Sevgi O

    2010-12-01

    To examine changes over time in the distribution of primary and secondary syphilis cases across states, using Lorenz curves and Gini coefficients. For each year from 1985 to 2007, the Gini coefficient for the state-level distribution of male and female syphilis cases was calculated. The Gini coefficient can range from 0 (indicating equality in syphilis rates across states) to 1 (indicating complete inequality such that all syphilis cases occur in one state). The Gini coefficients for men are notably lower (indicating more equality in the distribution of syphilis across states) in recent years (in which men who have sex with men (MSM) account for most syphilis cases) than in the heterosexual epidemic of the late 1980s and early 1990s. Although syphilis rates in men were similar in 1995 and 2007 (6.7 and 6.6 per 100,000, respectively), the Gini coefficient for male syphilis decreased from 0.523 in 1995 to 0.333 in 2007. For syphilis in women, Gini coefficients have not shown the same degree of decline. The spread of MSM syphilis cases to urban areas across the nation is likely to be a main cause of the decreased concentration of male syphilis cases across states from 1995 to 2007.

  16. Electrical Circuits and Water Analogies

    Science.gov (United States)

    Smith, Frederick A.; Wilson, Jerry D.

    1974-01-01

    Briefly describes water analogies for electrical circuits and presents plans for the construction of apparatus to demonstrate these analogies. Demonstrations include series circuits, parallel circuits, and capacitors. (GS)

  17. Electric circuits essentials

    CERN Document Server

    REA, Editors of

    2012-01-01

    REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Electric Circuits I includes units, notation, resistive circuits, experimental laws, transient circuits, network theorems, techniques of circuit analysis, sinusoidal analysis, polyph

  18. Piezoelectric drive circuit

    Science.gov (United States)

    Treu, C.A. Jr.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes. 7 figs.

  19. Load testing circuit

    DEFF Research Database (Denmark)

    2009-01-01

    A load testing circuit a circuit tests the load impedance of a load connected to an amplifier. The load impedance includes a first terminal and a second terminal, the load testing circuit comprising a signal generator providing a test signal of a defined bandwidth to the first terminal of the load...

  20. Short-circuit logic

    NARCIS (Netherlands)

    Bergstra, J.A.; Ponse, A.

    2010-01-01

    Short-circuit evaluation denotes the semantics of propositional connectives in which the second argument is only evaluated if the first argument does not suffice to determine the value of the expression. In programming, short-circuit evaluation is widely used. A short-circuit logic is a variant of

  1. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten

    2011-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital

  2. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten

    2010-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital

  3. Algorithmic Optimal Management of a Potable Water Distribution System: Application to the Primary Network of Bonaberi (Douala, Cameroon

    Directory of Open Access Journals (Sweden)

    Zineb Simeu-Abazi

    2009-11-01

    Full Text Available The optimal management of a potable water distribution system requires the control of the reference (standard data, the control points, control of the drainage parameters (pressure, flow, etc. and maintenance parameters. The control of the mentioned data defines the network learning process [1]. Besides classic IT functions of acquisition, storage and data processing, a geographical information system (GIS can be used as the basis for an alarm system, allowing one to identify and to localize the presence of water leaks in the network [2]. In this article we propose an algorithm coupling the various drainage parameters for the management of the network. The algorithm leads to an optimal management of leaks. An application is in progress on the primary network in the region of Bonaberi in Douala, the largest city of Cameroon.

  4. Distribution, persistence and interchange of Epstein-Barr virus strains among PBMC, plasma and saliva of primary infection subjects.

    Science.gov (United States)

    Kwok, Hin; Chan, Koon Wing; Chan, Kwok Hung; Chiang, Alan Kwok Shing

    2015-01-01

    Our study aimed at investigating the distribution, persistence and interchange of viral strains among peripheral blood mononuclear cells (PBMC), plasma and saliva of primary Epstein-Barr virus (EBV) infection subjects. Twelve infectious mononucleosis (IM) patients and eight asymptomatic individuals (AS) with primary EBV infection were followed longitudinally at several time points for one year from the time of diagnosis, when blood and saliva samples were collected and separated into PBMC, plasma and saliva, representing circulating B cell, plasma and epithelial cell compartments, respectively. To survey the viral strains, genotyping assays for the natural polymorphisms in two latent EBV genes, EBNA2 and LMP1, were performed and consisted of real-time PCR on EBNA2 to distinguish type 1 and 2 viruses, fluorescent-based 30-bp typing assay on LMP1 to distinguish deletion and wild type LMP1, and fluorescent-based heteroduplex tracking assays on both EBNA2 and LMP1 to distinguish defined polymorphic variants. No discernible differences were observed between IM patients and AS. Multiple viral strains were acquired early at the start of infection. Stable persistence of dominant EBV strains in the same tissue compartment was observed throughout the longitudinal samples. LMP1-defined strains, China 1, China 2 and Mediterranean+, were the most common strains observed. EBNA2-defined groups 1 and 3e predominated the PBMC and saliva compartments. Concordance of EBNA2 and LMP1 strains between PBMC and saliva suggested ready interchange of viruses between circulating B cell and epithelial cell pools, whilst discordance of viral strains observed between plasma and PBMC/saliva indicated presence of viral pools in other undetermined tissue compartments. Taken together, the results indicated that the distribution, persistence and interchange of viral strains among the tissue compartments are more complex than those proposed by the current model of EBV life cycle.

  5. Smart Circuit Breaker Communication Infrastructure

    Directory of Open Access Journals (Sweden)

    Octavian Mihai MACHIDON

    2017-11-01

    Full Text Available The expansion of the Internet of Things has fostered the development of smart technologies in fields such as power transmission and distribution systems (as is the Smart Grid and also in regard to home automation (the Smart Home concept. This paper addresses the network communication infrastructure for a Smart Circuit Breaker system, a novel application at the edge of the two afore-mentioned systems (Smart Grid and Smart Home. Such a communication interface has high requirements from functionality, performance and security point of views, given the large amount of distributed connected elements and the real-time information transmission and system management. The paper describes the design and implementation of the data server, Web interface and the embedded networking capabilities of the smart circuit breakers, underlining the protocols and communication technologies used.

  6. Feedback in analog circuits

    CERN Document Server

    Ochoa, Agustin

    2016-01-01

    This book describes a consistent and direct methodology to the analysis and design of analog circuits with particular application to circuits containing feedback. The analysis and design of circuits containing feedback is generally presented by either following a series of examples where each circuit is simplified through the use of insight or experience (someone else’s), or a complete nodal-matrix analysis generating lots of algebra. Neither of these approaches leads to gaining insight into the design process easily. The author develops a systematic approach to circuit analysis, the Driving Point Impedance and Signal Flow Graphs (DPI/SFG) method that does not require a-priori insight to the circuit being considered and results in factored analysis supporting the design function. This approach enables designers to account fully for loading and the bi-directional nature of elements both in the feedback path and in the amplifier itself, properties many times assumed negligible and ignored. Feedback circuits a...

  7. Grounding and shielding circuits and interference

    CERN Document Server

    Morrison, Ralph

    2016-01-01

    Applies basic field behavior in circuit design and demonstrates how it relates to grounding and shielding requirements and techniques in circuit design This book connects the fundamentals of electromagnetic theory to the problems of interference in all types of electronic design. The text covers power distribution in facilities, mixing of analog and digital circuitry, circuit board layout at high clock rates, and meeting radiation and susceptibility standards. The author examines the grounding and shielding requirements and techniques in circuit design and applies basic physics to circuit behavior. The sixth edition of this book has been updated with new material added throughout the chapters where appropriate. The presentation of the book has also been rearranged in order to reflect the current trends in the field.

  8. Thermohydraulic calculations of PWR primary circuits

    International Nuclear Information System (INIS)

    Botelho, D.A.

    1984-01-01

    Some mathematical and numerical models from Retran computer codes aiming to simulate reactor transients, are presented. The equations used for calculating one-dimensional flow are integrated using mathematical methods from Flash code, with steam code to correlate the variables from thermodynamic state. The algorithm obtained was used for calculating a PWR reactor. (E.G.) [pt

  9. Geographical distribution of the annual mean radon concentrations in primary schools of Southern Serbia – application of geostatistical methods

    International Nuclear Information System (INIS)

    Bossew, P.; Žunić, Z.S.; Stojanovska, Z.; Tollefsen, T.; Carpentieri, C.; Veselinović, N.; Komatina, S.; Vaupotič, J.; Simović, R.D.; Antignani, S.; Bochicchio, F.

    2014-01-01

    Between 2008 and 2011 a survey of radon ( 222 Rn) was performed in schools of several districts of Southern Serbia. Some results have been published previously (Žunić et al., 2010; Carpentieri et al., 2011; Žunić et al., 2013). This article concentrates on the geographical distribution of the measured Rn concentrations. Applying geostatistical methods we generate “school radon maps” of expected concentrations and of estimated probabilities that a concentration threshold is exceeded. The resulting maps show a clearly structured spatial pattern which appears related to the geological background. In particular in areas with vulcanite and granitoid rocks, elevated radon (Rn) concentrations can be expected. The “school radon map” can therefore be considered as proxy to a map of the geogenic radon potential, and allows identification of radon-prone areas, i.e. areas in which higher Rn radon concentrations can be expected for natural reasons. It must be stressed that the “radon hazard”, or potential risk, estimated this way, has to be distinguished from the actual radon risk, which is a function of exposure. This in turn may require (depending on the target variable which is supposed to measure risk) considering demographic and sociological reality, i.e. population density, distribution of building styles and living habits. -- Highlights: • A map of Rn concentrations in primary schools of Southern Serbia. • Application of geostatistical methods. • Correlation with geology found. • Can serve as proxy to identify radon prone areas

  10. New equivalent lumped electrical circuit for piezoelectric transformers.

    Science.gov (United States)

    Gonnard, Paul; Schmitt, P M; Brissaud, Michel

    2006-04-01

    A new equivalent circuit is proposed for a contour-vibration-mode piezoelectric transformer (PT). It is shown that the usual lumped equivalent circuit derived from the conventional Mason approach is not accurate. The proposed circuit, built on experimental measurements, makes an explicit difference between the elastic energies stored respectively on the primary and secondary parts. The experimental and theoretical resonance frequencies with the secondary in open or short circuit are in good agreement as well as the output "voltage-current" characteristic and the optimum efficiency working point. This circuit can be extended to various PT configurations and appears to be a useful tool for modeling electronic devices that integrate piezoelectric transformers.

  11. Interconnect rise time in superconducting integrating circuits

    International Nuclear Information System (INIS)

    Preis, D.; Shlager, K.

    1988-01-01

    The influence of resistive losses on the voltage rise time of an integrated-circuit interconnection is reported. A distribution-circuit model is used to present the interconnect. Numerous parametric curves are presented based on numerical evaluation of the exact analytical expression for the model's transient response. For the superconducting case in which the series resistance of the interconnect approaches zero, the step-response rise time is longer but signal strength increases significantly

  12. Electric circuits and signals

    CERN Document Server

    Sabah, Nassir H

    2007-01-01

    Circuit Variables and Elements Overview Learning Objectives Electric Current Voltage Electric Power and Energy Assigned Positive Directions Active and Passive Circuit Elements Voltage and Current Sources The Resistor The Capacitor The Inductor Concluding Remarks Summary of Main Concepts and Results Learning Outcomes Supplementary Topics on CD Problems and Exercises Basic Circuit Connections and Laws Overview Learning Objectives Circuit Terminology Kirchhoff's Laws Voltage Division and Series Connection of Resistors Current Division and Parallel Connection of Resistors D-Y Transformation Source Equivalence and Transformation Reduced-Voltage Supply Summary of Main Concepts and Results Learning Outcomes Supplementary Topics and Examples on CD Problems and Exercises Basic Analysis of Resistive Circuits Overview Learning Objectives Number of Independent Circuit Equations Node-Voltage Analysis Special Considerations in Node-Voltage Analysis Mesh-Current Analysis Special Conside...

  13. [Shunt and short circuit].

    Science.gov (United States)

    Rangel-Abundis, Alberto

    2006-01-01

    Shunt and short circuit are antonyms. In French, the term shunt has been adopted to denote the alternative pathway of blood flow. However, in French, as well as in Spanish, the word short circuit (court-circuit and cortocircuito) is synonymous with shunt, giving rise to a linguistic and scientific inconsistency. Scientific because shunt and short circuit made reference to a phenomenon that occurs in the field of the physics. Because shunt and short circuit are antonyms, it is necessary to clarify that shunt is an alternative pathway of flow from a net of high resistance to a net of low resistance, maintaining the stream. Short circuit is the interruption of the flow, because a high resistance impeaches the flood. This concept is applied to electrical and cardiovascular physiology, as well as to the metabolic pathways.

  14. The Composition of Comet C/2012 K1 (PanSTARRS) and the Distribution of Primary Volatile Abundances Among Comets

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Nathan X.; Gibb, Erika L. [Department of Physics and Astronomy, University of Missouri-St. Louis, 503 Benton Hall, One University Blvd., St. Louis, MO 63121 (United States); Bonev, Boncho P.; DiSanti, Michael A.; Mumma, Michael J.; Villanueva, Geronimo L.; Paganini, Lucas, E-mail: nxrq67@mail.umsl.edu [Goddard Center for Astrobiology, NASA Goddard Space Flight Center, Mail Stop 690, Greenbelt, MD 20771 (United States)

    2017-04-01

    On 2014 May 22 and 24 we characterized the volatile composition of the dynamically new Oort cloud comet C/2012 K1 (PanSTARRS) using the long-slit, high resolution ( λ /Δ λ  ≈ 25,000) near-infrared echelle spectrograph (NIRSPEC) at the 10 m Keck II telescope on Maunakea, Hawaii. We detected fluorescent emission from six primary volatiles (H{sub 2}O, HCN, CH{sub 4}, C{sub 2}H{sub 6}, CH{sub 3}OH, and CO). Upper limits were derived for C{sub 2}H{sub 2}, NH{sub 3}, and H{sub 2}CO. We report rotational temperatures, production rates, and mixing ratios (relative to water). Compared with median abundance ratios for primary volatiles in other sampled Oort cloud comets, trace gas abundance ratios in C/2012 K1 (PanSTARRS) for CO and HCN are consistent, but CH{sub 3}OH and C{sub 2}H{sub 6} are enriched while H{sub 2}CO, CH{sub 4}, and possibly C{sub 2}H{sub 2} are depleted. When placed in context with comets observed in the near-infrared to date, the data suggest a continuous distribution of abundances of some organic volatiles (HCN, C{sub 2}H{sub 6}, CH{sub 3}OH, CH{sub 4}) among the comet population. The level of “enrichment” or “depletion” in a given comet does not necessarily correlate across all molecules sampled, suggesting that chemical diversity among comets may be more complex than the simple organics-enriched, organics-normal, and organics-depleted framework.

  15. TH-AB-201-05: Determining the Direction Distribution of the Primary Radiation for a Cyberknife-M6

    International Nuclear Information System (INIS)

    Henzen, D; Schmidhalter, D; Volken, W; Mackeprang, P-H; Malthaner, M; K Fix, M; Manser, P; C Zanella, C

    2016-01-01

    Purpose: Radiation protection regulatory differentiates between primary and scatter radiation. Whereas for conventional clinical linear accelerators the solid angle for primary radiation is planar, the Cyberknife (Accuray Inc., Sunnyvale, CA) may point its beam in all spatial directions. In order to be able to judge on radiation protection calculations for a Cyberknife-M6 vault, the direction distribution for delivered plans was evaluated based on clinical experiences. Methods: The log-files of 121 delivered patient treatment plans were exported, divided into cranial and extra-cranial treatments and the delivered monitor units (MU) together with the corresponding beam directions were analyzed. This MU-weighted spatial distribution was then projected to a 9.5 × 5.9 × 3.9 m 3 vault, generating an “intensity map” using a binning of 50 × 50 cm 2 . The factor of direction (FOD) is reported as a fraction of the total applied MUs to the walls, ceiling and floor in the perspective of a patient lying in head-first-supine position on the couch. In this study, the term intFOD refers to the integral FOD and maxFOD refers to the maximal FOD for a single bin. Results: For all kind of treatments and collimators, intFOD and maxFOD for the wall behind the patient’s head is 0.0. The intFOD for the floor varies between 0.65 and 0.74. For the ceiling, maxFOD is 0.002 and 0.0 for cranial and extra-cranial cases, respectively. The intFOD for the wall at the patient’s feet, is 0.094 for cranial and 0.005 for extra-cranial cases. There is nearly no difference between the maxFOD of the right and left wall for cranial cases, whereas for extra-cranial cases these numbers differ by a factor of 1.75. Conclusion: The varying FODs for the Cyberknife were quantified based on delivered treatment plans. These findings are helpful regarding the design of Cyberknife vaults.

  16. Analog circuits cookbook

    CERN Document Server

    Hickman, Ian

    2013-01-01

    Analog Circuits Cookbook presents articles about advanced circuit techniques, components and concepts, useful IC for analog signal processing in the audio range, direct digital synthesis, and ingenious video op-amp. The book also includes articles about amplitude measurements on RF signals, linear optical imager, power supplies and devices, and RF circuits and techniques. Professionals and students of electrical engineering will find the book informative and useful.

  17. Analog circuit design

    CERN Document Server

    Dobkin, Bob

    2012-01-01

    Analog circuit and system design today is more essential than ever before. With the growth of digital systems, wireless communications, complex industrial and automotive systems, designers are being challenged to develop sophisticated analog solutions. This comprehensive source book of circuit design solutions aids engineers with elegant and practical design techniques that focus on common analog challenges. The book's in-depth application examples provide insight into circuit design and application solutions that you can apply in today's demanding designs. <

  18. Regenerative feedback resonant circuit

    Science.gov (United States)

    Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.

    2014-09-02

    A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.

  19. Circuit de distribution des poissons frais et congelés à Abidjan : Hygiène et évaluation microbiologique

    Directory of Open Access Journals (Sweden)

    Yiwo Thecle Noée Veline N'GUESSAM

    2018-03-01

    Full Text Available Fish is one of the main sources of animal protein commercialized fresh or processed in Côte d’Ivoire. Health problems and even nutritional risks were noticed in spite of the existence of self-control systems and official controls in place. The objective of this study is to determine the causes of the sanitary insecurity and to evaluate the microbiological quality of the fish sold in the distribution channels of Abidjan. The Ishikawa method was used to identify the causes of health insecurity. The results of the microbiological analyzes carried out on frozen fish (Trachurus trachurus, Scombers combrus and fresh (Chrysichthys nigrodigitafus show that the coliform count is high (7.1 102 and 8.1 101 in fresh fish. However, Staphylococcus aureusis was below 10 CFU/g of product. Salmonella spp was absent in all the samples under the investigation. Labor remains the major source of germs and the most important “weakest link”. Appropriate corrective action will reduce the sanitary insecurity of fishsold in the distribution system by around 90%.

  20. Design considerations of fission and corrosion product in primary system of MONJU

    International Nuclear Information System (INIS)

    Yanagisawa, T.; Akagane, K.; Yamamoto, K.; Kawashima, K.

    1976-01-01

    General influence of fission and corrosion products in primary system on MONJU plant design is reviewed. Various research and development works are now in progress to decrease the generation rate, to remove the products more effectively and to develop the methods of evaluation the behaviour of radioactive products. The inventory and distribution of fission and corrosion products in the primary circuit of MONJU are given. The radiation levels on the primary components are estimated to be several roentgens per hour. (author)

  1. CMOS circuits manual

    CERN Document Server

    Marston, R M

    1995-01-01

    CMOS Circuits Manual is a user's guide for CMOS. The book emphasizes the practical aspects of CMOS and provides circuits, tables, and graphs to further relate the fundamentals with the applications. The text first discusses the basic principles and characteristics of the CMOS devices. The succeeding chapters detail the types of CMOS IC, including simple inverter, gate and logic ICs and circuits, and complex counters and decoders. The last chapter presents a miscellaneous collection of two dozen useful CMOS circuits. The book will be useful to researchers and professionals who employ CMOS circu

  2. Timergenerator circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Timer/Generator Circuits Manual is an 11-chapter text that deals mainly with waveform generator techniques and circuits. Each chapter starts with an explanation of the basic principles of its subject followed by a wide range of practical circuit designs. This work presents a total of over 300 practical circuits, diagrams, and tables.Chapter 1 outlines the basic principles and the different types of generator. Chapters 2 to 9 deal with a specific type of waveform generator, including sine, square, triangular, sawtooth, and special waveform generators pulse. These chapters also include pulse gen

  3. Electronic devices and circuits

    CERN Document Server

    Pridham, Gordon John

    1968-01-01

    Electronic Devices and Circuits, Volume 1 deals with the design and applications of electronic devices and circuits such as passive components, diodes, triodes and transistors, rectification and power supplies, amplifying circuits, electronic instruments, and oscillators. These topics are supported with introductory network theory and physics. This volume is comprised of nine chapters and begins by explaining the operation of resistive, inductive, and capacitive elements in direct and alternating current circuits. The theory for some of the expressions quoted in later chapters is presented. Th

  4. Maximum Acceleration Recording Circuit

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Coarsely digitized maximum levels recorded in blown fuses. Circuit feeds power to accelerometer and makes nonvolatile record of maximum level to which output of accelerometer rises during measurement interval. In comparison with inertia-type single-preset-trip-point mechanical maximum-acceleration-recording devices, circuit weighs less, occupies less space, and records accelerations within narrower bands of uncertainty. In comparison with prior electronic data-acquisition systems designed for same purpose, circuit simpler, less bulky, consumes less power, costs and analysis of data recorded in magnetic or electronic memory devices. Circuit used, for example, to record accelerations to which commodities subjected during transportation on trucks.

  5. MOS integrated circuit design

    CERN Document Server

    Wolfendale, E

    2013-01-01

    MOS Integral Circuit Design aims to help in the design of integrated circuits, especially large-scale ones, using MOS Technology through teaching of techniques, practical applications, and examples. The book covers topics such as design equation and process parameters; MOS static and dynamic circuits; logic design techniques, system partitioning, and layout techniques. Also featured are computer aids such as logic simulation and mask layout, as well as examples on simple MOS design. The text is recommended for electrical engineers who would like to know how to use MOS for integral circuit desi

  6. Circuits and filters handbook

    CERN Document Server

    Chen, Wai-Kai

    2003-01-01

    A bestseller in its first edition, The Circuits and Filters Handbook has been thoroughly updated to provide the most current, most comprehensive information available in both the classical and emerging fields of circuits and filters, both analog and digital. This edition contains 29 new chapters, with significant additions in the areas of computer-aided design, circuit simulation, VLSI circuits, design automation, and active and digital filters. It will undoubtedly take its place as the engineer's first choice in looking for solutions to problems encountered in the design, analysis, and behavi

  7. Security electronics circuits manual

    CERN Document Server

    MARSTON, R M

    1998-01-01

    Security Electronics Circuits Manual is an invaluable guide for engineers and technicians in the security industry. It will also prove to be a useful guide for students and experimenters, as well as providing experienced amateurs and DIY enthusiasts with numerous ideas to protect their homes, businesses and properties.As with all Ray Marston's Circuits Manuals, the style is easy-to-read and non-mathematical, with the emphasis firmly on practical applications, circuits and design ideas. The ICs and other devices used in the practical circuits are modestly priced and readily available ty

  8. Part of the hydrogen in the intergranular crack by stress corrosion in primary circuit for the 600 and 690 nickel base alloys; Role de l'hydrogene dans le mecanisme de fissuration intergranulaire par corrosion sous contrainte en milieu primaire des alliages base nickel 600 et 690

    Energy Technology Data Exchange (ETDEWEB)

    Odemer, G.; Coudurier, A.; Jambon, F.; Chene, J. [CEA Saclay, Dept. de Physico-Chimie (DPC/SCCME/LECA), 91 - Gif sur Yvette (France); Odemer, G.; Coudurier, A.; Chene, J. [Evry Univ., UMR 8587 CNRS / CEA, LAMBE, 91 (France)

    2007-07-01

    The aim of this study is, in a first part, to characterize the hydrogen embrittlement sensitivity of the 600 and 690 based alloys in order to better understand the hydrogen role in the stress corrosion mechanism which appears in theses alloys in the primary circuit of the PWR type reactors. The authors studies how the hydrogen embrittlement is resulting from an interaction between the hydrogen and the plastic deformation. (A.L.B.)

  9. Solution of multiple circuits of steam cycle HTR system

    International Nuclear Information System (INIS)

    Li, Fu; Wang, Dengying; Hao, Chen; Zheng, Yanhua

    2014-01-01

    In order to analyze the dynamic operation performance and safety characteristics of the steam cycle high temperature gas cooled reactor (HTR) systems, it is necessary to find the solution of the whole HTR systems with all coupled circuits, including the primary circuit, the secondary circuit, and the residual heat removal system (RHRS). Considering that those circuits have their own individual fluidity and characteristics, some existing code packages for independent circuits themselves have been developed, for example THEMRIX and TINTE code for the primary circuit of the pebble bed reactor, BLAST for once through steam generator. To solve the coupled steam cycle HTR systems, a feasible way is to develop coupling method to integrate these independent code packages. This paper presents several coupling methods, e.g. the equivalent component method between the primary circuit and steam generator which reflect the close coupling relationship, the overlapping domain decomposition method between the primary circuit and the passive RHRS which reflects the loose coupling relationship. Through this way, the whole steam cycle HTR system with multiple circuits can be easily and efficiently solved by integration of several existing code packages. Based on this methodology, a code package TINTE–BLAST–RHRS was developed. Using this code package, some operation performance of HTR–PM was analyzed, such as the start-up process of the plant, and the depressurized loss of forced cooling accident when different number of residual heat removal trains is operated

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

    International Nuclear Information System (INIS)

    Blagovechtchenski, A.; Leontieva, V.; Mitrioukhin, A.

    1997-01-01

    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

  11. 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.

  12. 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)

    1998-12-31

    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.

  13. Brain Circuits Encoding Reward from Pain Relief.

    Science.gov (United States)

    Navratilova, Edita; Atcherley, Christopher W; Porreca, Frank

    2015-11-01

    Relief from pain in humans is rewarding and pleasurable. Primary rewards, or reward-predictive cues, are encoded in brain reward/motivational circuits. While considerable advances have been made in our understanding of reward circuits underlying positive reinforcement, less is known about the circuits underlying the hedonic and reinforcing actions of pain relief. We review findings from electrophysiological, neuroimaging, and behavioral studies supporting the concept that the rewarding effect of pain relief requires opioid signaling in the anterior cingulate cortex (ACC), activation of midbrain dopamine neurons, and the release of dopamine in the nucleus accumbens (NAc). Understanding of circuits that govern the reward of pain relief may allow the discovery of more effective and satisfying therapies for patients with acute or chronic pain.

  14. Modeling the transport of nitrogen in an NPP-2006 reactor circuit

    Science.gov (United States)

    Stepanov, O. E.; Galkin, I. Yu.; Sledkov, R. M.; Melekh, S. S.; Strebnev, N. A.

    2016-07-01

    Efficient radiation protection of the public and personnel requires detecting an accident-initiating event quickly. Specifically, if a heat-exchange tube in a steam generator is ruptured, the 16N radioactive nitrogen isotope, which contributes to a sharp increase in the steam activity before the turbine, may serve as the signaling component. This isotope is produced in the core coolant and is transported along the circulation circuit. The aim of the present study was to model the transport of 16N in the primary and the secondary circuits of a VVER-1000 reactor facility (RF) under nominal operation conditions. KORSAR/GP and RELAP5/Mod.3.2 codes were used to perform the calculations. Computational models incorporating the major components of the primary and the secondary circuits of an NPP-2006 RF were constructed. These computational models were subjected to cross-verification, and the calculation results were compared to the experimental data on the distribution of the void fraction over the steam generator height. The models were proven to be valid. It was found that the time of nitrogen transport from the core to the heat-exchange tube leak was no longer than 1 s under RF operation at a power level of 100% N nom with all primary circuit pumps activated. The time of nitrogen transport from the leak to the γ-radiation detection unit under the same operating conditions was no longer than 9 s, and the nitrogen concentration in steam was no less than 1.4% (by mass) of its concentration at the reactor outlet. These values were obtained using conservative approaches to estimating the leak flow and the transport time, but the radioactive decay of nitrogen was not taken into account. Further research concerned with the calculation of thermohydraulic processes should be focused on modeling the transport of nitrogen under RF operation with some primary circuit pumps deactivated.

  15. Distribution

    Science.gov (United States)

    John R. Jones

    1985-01-01

    Quaking aspen is the most widely distributed native North American tree species (Little 1971, Sargent 1890). It grows in a great diversity of regions, environments, and communities (Harshberger 1911). Only one deciduous tree species in the world, the closely related Eurasian aspen (Populus tremula), has a wider range (Weigle and Frothingham 1911)....

  16. Circuits on Cylinders

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt; Miltersen, Peter Bro; Vinay, V

    2006-01-01

    We consider the computational power of constant width polynomial size cylindrical circuits and nondeterministic branching programs. We show that every function computed by a Pi2 o MOD o AC0 circuit can also be computed by a constant width polynomial size cylindrical nondeterministic branching pro...

  17. CMOS analog circuit design

    CERN Document Server

    Allen, Phillip E

    1987-01-01

    This text presents the principles and techniques for designing analog circuits to be implemented in a CMOS technology. The level is appropriate for seniors and graduate students familiar with basic electronics, including biasing, modeling, circuit analysis, and some familiarity with frequency response. Students learn the methodology of analog integrated circuit design through a hierarchically-oriented approach to the subject that provides thorough background and practical guidance for designing CMOS analog circuits, including modeling, simulation, and testing. The authors' vast industrial experience and knowledge is reflected in the circuits, techniques, and principles presented. They even identify the many common pitfalls that lie in the path of the beginning designer--expert advice from veteran designers. The text mixes the academic and practical viewpoints in a treatment that is neither superficial nor overly detailed, providing the perfect balance.

  18. Automatic location of short circuit faults

    Energy Technology Data Exchange (ETDEWEB)

    Lehtonen, M. [VTT Energy, Espoo (Finland); Hakola, T.; Antila, E. [ABB Power Oy, Helsinki (Finland); Seppaenen, M. [North-Carelian Power Company (Finland)

    1996-12-31

    In this presentation, the automatic location of short circuit faults on medium voltage distribution lines, based on the integration of computer systems of medium voltage distribution network automation is discussed. First the distribution data management systems and their interface with the substation telecontrol, or SCADA systems, is studied. Then the integration of substation telecontrol system and computerised relay protection is discussed. Finally, the implementation of the fault location system is presented and the practical experience with the system is discussed

  19. Automatic location of short circuit faults

    Energy Technology Data Exchange (ETDEWEB)

    Lehtonen, M [VTT Energy, Espoo (Finland); Hakola, T; Antila, E [ABB Power Oy (Finland); Seppaenen, M [North-Carelian Power Company (Finland)

    1998-08-01

    In this chapter, the automatic location of short circuit faults on medium voltage distribution lines, based on the integration of computer systems of medium voltage distribution network automation is discussed. First the distribution data management systems and their interface with the substation telecontrol, or SCADA systems, is studied. Then the integration of substation telecontrol system and computerized relay protection is discussed. Finally, the implementation of the fault location system is presented and the practical experience with the system is discussed

  20. Automatic location of short circuit faults

    Energy Technology Data Exchange (ETDEWEB)

    Lehtonen, M [VTT Energy, Espoo (Finland); Hakola, T; Antila, E [ABB Power Oy, Helsinki (Finland); Seppaenen, M [North-Carelian Power Company (Finland)

    1997-12-31

    In this presentation, the automatic location of short circuit faults on medium voltage distribution lines, based on the integration of computer systems of medium voltage distribution network automation is discussed. First the distribution data management systems and their interface with the substation telecontrol, or SCADA systems, is studied. Then the integration of substation telecontrol system and computerised relay protection is discussed. Finally, the implementation of the fault location system is presented and the practical experience with the system is discussed

  1. Nascent energy distribution of the Criegee intermediate CH2OO from direct dynamics calculations of primary ozonide dissociation

    Science.gov (United States)

    Pfeifle, Mark; Ma, Yong-Tao; Jasper, Ahren W.; Harding, Lawrence B.; Hase, William L.; Klippenstein, Stephen J.

    2018-05-01

    Ozonolysis produces chemically activated carbonyl oxides (Criegee intermediates, CIs) that are either stabilized or decompose directly. This branching has an important impact on atmospheric chemistry. Prior theoretical studies have employed statistical models for energy partitioning to the CI arising from dissociation of the initially formed primary ozonide (POZ). Here, we used direct dynamics simulations to explore this partitioning for decomposition of c-C2H4O3, the POZ in ethylene ozonolysis. A priori estimates for the overall stabilization probability were then obtained by coupling the direct dynamics results with master equation simulations. Trajectories were initiated at the concerted cycloreversion transition state, as well as the second transition state of a stepwise dissociation pathway, both leading to a CI (H2COO) and formaldehyde (H2CO). The resulting CI energy distributions were incorporated in master equation simulations of CI decomposition to obtain channel-specific stabilized CI (sCI) yields. Master equation simulations of POZ formation and decomposition, based on new high-level electronic structure calculations, were used to predict yields for the different POZ decomposition channels. A non-negligible contribution of stepwise POZ dissociation was found, and new mechanistic aspects of this pathway were elucidated. By combining the trajectory-based channel-specific sCI yields with the channel branching fractions, an overall sCI yield of (48 ± 5)% was obtained. Non-statistical energy release was shown to measurably affect sCI formation, with statistical models predicting significantly lower overall sCI yields (˜30%). Within the range of experimental literature values (35%-54%), our trajectory-based calculations favor those clustered at the upper end of the spectrum.

  2. Differential distribution of age and HBV serological markers in liver cirrhosis and non-cirrhotic patients with primary liver cancer

    Directory of Open Access Journals (Sweden)

    XU Xiuhua

    2013-03-01

    Full Text Available ObjectiveTo compare the age distributions and presence of hepatitis B virus (HBV serological markers between primary hepatic cancer (PHC patients with and without liver cirrhosis. MethodsA total of 547 PHC cases were analyzed retrospectively. After dividing into two groups according to liver cirrhosis status, the between-group differences in age and HBV serological markers, such as hepatitis B e antigen (HBeAg status, were statistically compared using the Chi-squared test. ResultsThe number of cirrhotic and non-cirrhotic PHC patients was 265 and 282, respectively. HBV infection was present in 221 cirrhotic PHC patients and 256 non-cirrhotic PHC patients (834% vs. 90.8%. There was a substantial bias in the proportion of males to females in the cirrhotic PHC patients (7.83∶1. The number of PHC patients <60 years old was similar between the cirrhotic and non-cirrhotic groups, but the non-cirrhotic group had significantly more patients >60 years old (P<0.005. In cirrhotic PHC patients, the HBV infection rate was highest in the <40 years old age group (96.7% and the HBeAg serological conversion rate was highest in the 40-60 years old age group (89.5%. In non-cirrhotic PHC patients, the 40-60 years old age group showed the highest HBV infection rate (90.3% but the lowest HBeAg serological conversion rate (80.0%. ConclusionPHC with liver cirrhosis mainly occurred in males, with the HBV infection rate being higher in individuals <60 years old. Non-cirrhotic PHC patients were more often >60 years old. Many of the HBV-infected PHC patients with cirrhosis had high HBeAg serological conversion rate.

  3. Nascent energy distribution of the Criegee intermediate CH2OO from direct dynamics calculations of primary ozonide dissociation.

    Science.gov (United States)

    Pfeifle, Mark; Ma, Yong-Tao; Jasper, Ahren W; Harding, Lawrence B; Hase, William L; Klippenstein, Stephen J

    2018-05-07

    Ozonolysis produces chemically activated carbonyl oxides (Criegee intermediates, CIs) that are either stabilized or decompose directly. This branching has an important impact on atmospheric chemistry. Prior theoretical studies have employed statistical models for energy partitioning to the CI arising from dissociation of the initially formed primary ozonide (POZ). Here, we used direct dynamics simulations to explore this partitioning for decomposition of c-C 2 H 4 O 3 , the POZ in ethylene ozonolysis. A priori estimates for the overall stabilization probability were then obtained by coupling the direct dynamics results with master equation simulations. Trajectories were initiated at the concerted cycloreversion transition state, as well as the second transition state of a stepwise dissociation pathway, both leading to a CI (H 2 COO) and formaldehyde (H 2 CO). The resulting CI energy distributions were incorporated in master equation simulations of CI decomposition to obtain channel-specific stabilized CI (sCI) yields. Master equation simulations of POZ formation and decomposition, based on new high-level electronic structure calculations, were used to predict yields for the different POZ decomposition channels. A non-negligible contribution of stepwise POZ dissociation was found, and new mechanistic aspects of this pathway were elucidated. By combining the trajectory-based channel-specific sCI yields with the channel branching fractions, an overall sCI yield of (48 ± 5)% was obtained. Non-statistical energy release was shown to measurably affect sCI formation, with statistical models predicting significantly lower overall sCI yields (∼30%). Within the range of experimental literature values (35%-54%), our trajectory-based calculations favor those clustered at the upper end of the spectrum.

  4. Species distribution and in vitro antifungal susceptibility of oral yeast isolates from Tanzanian HIV-infected patients with primary and recurrent oropharyngeal candidiasis.

    NARCIS (Netherlands)

    Hamza, O.J.M.; Matee, M.I.N.; Moshi, M.J.; Simon, E.N.; Mugusi, F.; Mikx, F.H.M.; Palenstein Helderman, W.H. van; Rijs, A.J.M.M.; Ven, A.J.A.M. van der; Verweij, P.E.

    2008-01-01

    BACKGROUND: In Tanzania, little is known on the species distribution and antifungal susceptibility profiles of yeast isolates from HIV-infected patients with primary and recurrent oropharyngeal candidiasis. METHODS: A total of 296 clinical oral yeasts were isolated from 292 HIV-infected patients

  5. Distribution patterns of the metastases of the lung carcinoma in relation to histological type of the primary tumor: An autopsy study

    Directory of Open Access Journals (Sweden)

    Ivana Savic Milovanovic

    2017-01-01

    Conclusions: While, overall, the most frequent hematogenous metastases occur in the liver and adrenal glands, various histological types of lung cancer show specific dissemination patterns. Knowing distribution of metastases is essential for making algorithms of treatment, as well as for improving clinical assessment of the patients with unclear clinical findings and suspicion on occult primary lung cancer.

  6. Approximate circuits for increased reliability

    Science.gov (United States)

    Hamlet, Jason R.; Mayo, Jackson R.

    2015-08-18

    Embodiments of the invention describe a Boolean circuit having a voter circuit and a plurality of approximate circuits each based, at least in part, on a reference circuit. The approximate circuits are each to generate one or more output signals based on values of received input signals. The voter circuit is to receive the one or more output signals generated by each of the approximate circuits, and is to output one or more signals corresponding to a majority value of the received signals. At least some of the approximate circuits are to generate an output value different than the reference circuit for one or more input signal values; however, for each possible input signal value, the majority values of the one or more output signals generated by the approximate circuits and received by the voter circuit correspond to output signal result values of the reference circuit.

  7. Troubleshooting analog circuits

    CERN Document Server

    Pease, Robert A

    1991-01-01

    Troubleshooting Analog Circuits is a guidebook for solving product or process related problems in analog circuits. The book also provides advice in selecting equipment, preventing problems, and general tips. The coverage of the book includes the philosophy of troubleshooting; the modes of failure of various components; and preventive measures. The text also deals with the active components of analog circuits, including diodes and rectifiers, optically coupled devices, solar cells, and batteries. The book will be of great use to both students and practitioners of electronics engineering. Other

  8. Modern TTL circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Modern TTL Circuits Manual provides an introduction to the basic principles of Transistor-Transistor Logic (TTL). This book outlines the major features of the 74 series of integrated circuits (ICs) and introduces the various sub-groups of the TTL family.Organized into seven chapters, this book begins with an overview of the basics of digital ICs. This text then examines the symbology and mathematics of digital logic. Other chapters consider a variety of topics, including waveform generator circuitry, clocked flip-flop and counter circuits, special counter/dividers, registers, data latches, com

  9. Circuit analysis with Multisim

    CERN Document Server

    Baez-Lopez, David

    2011-01-01

    This book is concerned with circuit simulation using National Instruments Multisim. It focuses on the use and comprehension of the working techniques for electrical and electronic circuit simulation. The first chapters are devoted to basic circuit analysis.It starts by describing in detail how to perform a DC analysis using only resistors and independent and controlled sources. Then, it introduces capacitors and inductors to make a transient analysis. In the case of transient analysis, it is possible to have an initial condition either in the capacitor voltage or in the inductor current, or bo

  10. Optoelectronics circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Optoelectronics Circuits Manual covers the basic principles and characteristics of the best known types of optoelectronic devices, as well as the practical applications of many of these optoelectronic devices. The book describes LED display circuits and LED dot- and bar-graph circuits and discusses the applications of seven-segment displays, light-sensitive devices, optocouplers, and a variety of brightness control techniques. The text also tackles infrared light-beam alarms and multichannel remote control systems. The book provides practical user information and circuitry and illustrations.

  11. 'Speedy' superconducting circuits

    International Nuclear Information System (INIS)

    Holst, T.

    1994-01-01

    The most promising concept for realizing ultra-fast superconducting digital circuits is the Rapid Single Flux Quantum (RSFQ) logic. The basic physical principle behind RSFQ logic, which include the storage and transfer of individual magnetic flux quanta in Superconducting Quantum Interference Devices (SQUIDs), is explained. A Set-Reset flip-flop is used as an example of the implementation of an RSFQ based circuit. Finally, the outlook for high-temperature superconducting materials in connection with RSFQ circuits is discussed in some details. (au)

  12. SITE WIDE SHORT CIRCUIT STUDY ASSESSMENT

    International Nuclear Information System (INIS)

    CARRATT, R.T.

    2004-01-01

    The Department of Energy requested that Fluor Hanford develop a plan to update the electrical distribution studies for FH managed facilities. Toward this end, an assessment of FH's nuclear facilities was performed to determine whether a current short circuit study of the facility electrical distribution system exists, and the status of such study. This report presents the methodology and results of that assessment. The assessment identified 29 relevant facilities. Of these, a short circuit study could not be identified for 15 facilities. A short circuit study was found to exist for fourteen facilities, however, of these 14, four were not released into a controlled document system, and two were not performed for the entire electrical distribution system. It is recommended that for four of the facilities no further action is required based upon the limited nature of the existing electrical system, or as in the case of PFP, the status of the existing short circuit study was determined adequate. For the majority of the facilities without a short circuit study, it is recommended that one is performed, and released into a controlled document system. Two facilities require further evaluation due to missing or conflicting documentation. For the remainder of the facilities, the recommendations are to review and revise as appropriate the existing study, and release into a controlled document system. A summation of the recommendations is presented

  13. Classical Simulation of Intermediate-Size Quantum Circuits

    OpenAIRE

    Chen, Jianxin; Zhang, Fang; Chen, Mingcheng; Huang, Cupjin; Newman, Michael; Shi, Yaoyun

    2018-01-01

    We introduce a distributed classical simulation algorithm for general quantum circuits, and present numerical results for calculating the output probabilities of universal random circuits. We find that we can simulate more qubits to greater depth than previously reported using the cluster supported by the Data Infrastructure and Search Technology Division of the Alibaba Group. For example, computing a single amplitude of an $8\\times 8$ qubit circuit with depth $40$ was previously beyond the r...

  14. Analogue circuits simulation

    Energy Technology Data Exchange (ETDEWEB)

    Mendo, C

    1988-09-01

    Most analogue simulators have evolved from SPICE. The history and description of SPICE-like simulators are given. From a mathematical formulation of the electronic circuit the following analysis are possible: DC, AC, transient, noise, distortion, Worst Case and Statistical.

  15. Printed circuit for ATLAS

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    A printed circuit board made by scientists in the ATLAS collaboration for the transition radiaton tracker (TRT). This will read data produced when a high energy particle crosses the boundary between two materials with different electrical properties.

  16. Magnonic logic circuits

    International Nuclear Information System (INIS)

    Khitun, Alexander; Bao Mingqiang; Wang, Kang L

    2010-01-01

    We describe and analyse possible approaches to magnonic logic circuits and basic elements required for circuit construction. A distinctive feature of the magnonic circuitry is that information is transmitted by spin waves propagating in the magnetic waveguides without the use of electric current. The latter makes it possible to exploit spin wave phenomena for more efficient data transfer and enhanced logic functionality. We describe possible schemes for general computing and special task data processing. The functional throughput of the magnonic logic gates is estimated and compared with the conventional transistor-based approach. Magnonic logic circuits allow scaling down to the deep submicrometre range and THz frequency operation. The scaling is in favour of the magnonic circuits offering a significant functional advantage over the traditional approach. The disadvantages and problems of the spin wave devices are also discussed.

  17. Peak reading detector circuit

    International Nuclear Information System (INIS)

    Courtin, E.; Grund, K.; Traub, S.; Zeeb, H.

    1975-01-01

    The peak reading detector circuit serves for picking up the instants during which peaks of a given polarity occur in sequences of signals in which the extreme values, their time intervals, and the curve shape of the signals vary. The signal sequences appear in measuring the foetal heart beat frequence from amplitude-modulated ultrasonic, electrocardiagram, and blood pressure signals. In order to prevent undesired emission of output signals from, e. g., disturbing intermediate extreme values, the circuit consists of the series connections of a circuit to simulate an ideal diode, a strong unit, a discriminator for the direction of charging current, a time-delay circuit, and an electronic switch lying in the decharging circuit of the storage unit. The time-delay circuit thereby causes storing of a preliminary maximum value being used only after a certain time delay for the emission of the output signal. If a larger extreme value occurs during the delay time the preliminary maximum value is cleared and the delay time starts running anew. (DG/PB) [de

  18. Color Coding of Circuit Quantities in Introductory Circuit Analysis Instruction

    Science.gov (United States)

    Reisslein, Jana; Johnson, Amy M.; Reisslein, Martin

    2015-01-01

    Learning the analysis of electrical circuits represented by circuit diagrams is often challenging for novice students. An open research question in electrical circuit analysis instruction is whether color coding of the mathematical symbols (variables) that denote electrical quantities can improve circuit analysis learning. The present study…

  19. Project Circuits in a Basic Electric Circuits Course

    Science.gov (United States)

    Becker, James P.; Plumb, Carolyn; Revia, Richard A.

    2014-01-01

    The use of project circuits (a photoplethysmograph circuit and a simple audio amplifier), introduced in a sophomore-level electric circuits course utilizing active learning and inquiry-based methods, is described. The development of the project circuits was initiated to promote enhanced engagement and deeper understanding of course content among…

  20. An assessment of equity in the distribution of non-financial health care inputs across public primary health care facilities in Tanzania.

    Science.gov (United States)

    Kuwawenaruwa, August; Borghi, Josephine; Remme, Michelle; Mtei, Gemini

    2017-07-11

    There is limited evidence on how health care inputs are distributed from the sub-national level down to health facilities and their potential influence on promoting health equity. To address this gap, this paper assesses equity in the distribution of health care inputs across public primary health facilities at the district level in Tanzania. This is a quantitative assessment of equity in the distribution of health care inputs (staff, drugs, medical supplies and equipment) from district to facility level. The study was carried out in three districts (Kinondoni, Singida Rural and Manyoni district) in Tanzania. These districts were selected because they were implementing primary care reforms. We administered 729 exit surveys with patients seeking out-patient care; and health facility surveys at 69 facilities in early 2014. A total of seventeen indices of input availability were constructed with the collected data. The distribution of inputs was considered in relation to (i) the wealth of patients accessing the facilities, which was taken as a proxy for the wealth of the population in the catchment area; and (ii) facility distance from the district headquarters. We assessed equity in the distribution of inputs through the use of equity ratios, concentration indices and curves. We found a significant pro-rich distribution of clinical staff and nurses per 1000 population. Facilities with the poorest patients (most remote facilities) have fewer staff per 1000 population than those with the least poor patients (least remote facilities): 0.6 staff per 1000 among the poorest, compared to 0.9 among the least poor; 0.7 staff per 1000 among the most remote facilities compared to 0.9 among the least remote. The negative concentration index for support staff suggests a pro-poor distribution of this cadre but the 45 degree dominated the concentration curve. The distribution of vaccines, antibiotics, anti-diarrhoeal, anti-malarials and medical supplies was approximately

  1. Circuit and interconnect design for high bit-rate applications

    NARCIS (Netherlands)

    Veenstra, H.

    2006-01-01

    This thesis presents circuit and interconnect design techniques and design flows that address the most difficult and ill-defined aspects of the design of ICs for high bit-rate applications. Bottlenecks in interconnect design, circuit design and on-chip signal distribution for high bit-rate

  2. Multi-phase AC/AC step-down converter for distribution systems

    Science.gov (United States)

    Aeloiza, Eddy C.; Burgos, Rolando P.

    2017-10-25

    A step-down AC/AC converter for use in an electric distribution system includes at least one chopper circuit for each one of a plurality of phases of the AC power, each chopper circuit including a four-quadrant switch coupled in series between primary and secondary sides of the chopper circuit and a current-bidirectional two-quadrant switch coupled between the secondary side of the chopper circuit and a common node. Each current-bidirectional two-quadrant switch is oriented in the same direction, with respect to the secondary side of the corresponding chopper circuit and the common node. The converter further includes a control circuit configured to pulse-width-modulate control inputs of the switches, to convert a first multiphase AC voltage at the primary sides of the chopper circuits to a second multiphase AC voltage at the secondary sides of the chopper circuits, the second multiphase AC voltage being lower in voltage than the first multiphase AC voltage.

  3. Protection of toroidal field coils using multiple circuits

    International Nuclear Information System (INIS)

    Thome, R.J.; Langton, W.G.; Mann, W.R.; Pillsbury, R.D.; Tarrh, J.M.

    1983-01-01

    The protection of toroidal field (TF) coils using multiple circuits is described. The discharge of a single-circuit TF system is given for purposes of definition. Two-circuit TF systems are analyzed and the results presented analytically and graphically. Induced currents, maximum discharge voltages, and discharge time constants are compared to the single-circuit system. Three-circuit TF systems are analyzed. In addition to induced currents, maximum discharge voltages, and time constants, several different discharge scenarios are included. The impacts of having discharge rates versus final maximum coil temperatures as requirements are examined. The out-of-plane forces which occur in the three-circuit system are analyzed using an approximate model. The analysis of multiplecircuit TF systems is briefly described and results for a Toroidal Fusion Core Experiment (TFCX) scale device are given based on computer analysis. The advantages and disadvantages of using multiple-circuit systems are summarized and discussed. The primary disadvantages of multiple circuits are the increased circuit complexity and potential for out-of-plane forces. These are offset by the substantial reduction in maximum discharge voltages, as well as other design options which become available when using multiple circuits

  4. Low latency asynchronous interface circuits

    Science.gov (United States)

    Sadowski, Greg

    2017-06-20

    In one form, a logic circuit includes an asynchronous logic circuit, a synchronous logic circuit, and an interface circuit coupled between the asynchronous logic circuit and the synchronous logic circuit. The asynchronous logic circuit has a plurality of asynchronous outputs for providing a corresponding plurality of asynchronous signals. The synchronous logic circuit has a plurality of synchronous inputs corresponding to the plurality of asynchronous outputs, a stretch input for receiving a stretch signal, and a clock output for providing a clock signal. The synchronous logic circuit provides the clock signal as a periodic signal but prolongs a predetermined state of the clock signal while the stretch signal is active. The asynchronous interface detects whether metastability could occur when latching any of the plurality of the asynchronous outputs of the asynchronous logic circuit using said clock signal, and activates the stretch signal while the metastability could occur.

  5. Thyroid volume in hypothyroidism due to autoimmune disease follows a unimodal distribution: evidence against primary thyroid atrophy and autoimmune thyroiditis being distinct diseases

    DEFF Research Database (Denmark)

    Carlé, Allan; Pedersen, Inge Bülow; Knudsen, Nils

    2009-01-01

    CONTEXT: Primary overt autoimmune hypothyroidism is often divided into primary idiopathic hypothyroidism with thyroid atrophy (Ord's disease) and hypothyroidism with goitre (Hashimoto's disease). OBJECTIVE: The aim of the present study was to characterize the two subtypes of disease. DESIGN...... program including thyroid ultrasonography and measurements of thyroid autoantibodies. Of the 144 patients investigated (58% of all invited), 139 were compared with 556 sex-, age-, and region-matched controls from the cohort. RESULTS: Patients had lower median (11.6 ml vs. 13.5 ml, P = 0.001) and a more...... dispersed distribution of thyroid volumes compared with controls (P thyroid volume showed a Gaussian distribution in both males and females with no bimodal pattern. Nearly all patients had measurable thyroid autoantibodies, but with increasing thyroid volume (quartile I, II, III, and IV...

  6. Junction and circuit fabrication

    International Nuclear Information System (INIS)

    Jackel, L.D.

    1980-01-01

    Great strides have been made in Josephson junction fabrication in the four years since the first IC SQUID meeting. Advances in lithography have allowed the production of devices with planar dimensions as small as a few hundred angstroms. Improved technology has provided ultra-high sensitivity SQUIDS, high-efficiency low-noise mixers, and complex integrated circuits. This review highlights some of the new fabrication procedures. The review consists of three parts. Part 1 is a short summary of the requirements on junctions for various applications. Part 2 reviews intergrated circuit fabrication, including tunnel junction logic circuits made at IBM and Bell Labs, and microbridge radiation sources made at SUNY at Stony Brook. Part 3 describes new junction fabrication techniques, the major emphasis of this review. This part includes a discussion of small oxide-barrier tunnel junctions, semiconductor barrier junctions, and microbridge junctions. Part 3 concludes by considering very fine lithography and limitations to miniaturization. (orig.)

  7. Data readout system utilizing photonic integrated circuit

    Energy Technology Data Exchange (ETDEWEB)

    Stopiński, S., E-mail: S.Stopinski@tue.nl [COBRA Research Institute, Eindhoven University of Technology (Netherlands); Institute of Microelectronics and Optoelectronics, Warsaw University of Technology (Poland); Malinowski, M.; Piramidowicz, R. [Institute of Microelectronics and Optoelectronics, Warsaw University of Technology (Poland); Smit, M.K.; Leijtens, X.J.M. [COBRA Research Institute, Eindhoven University of Technology (Netherlands)

    2013-10-11

    We describe a novel optical solution for data readout systems. The core of the system is an Indium-Phosphide photonic integrated circuit performing as a front-end readout unit. It functions as an optical serializer in which the serialization of the input signal is provided by means of on-chip optical delay lines. The circuit employs electro-optic phase shifters to build amplitude modulators, power splitters for signal distribution, semiconductor optical amplifiers for signal amplification as well as on-chip reflectors. We present the concept of the system, the design and first characterization results of the devices that were fabricated in a multi-project wafer run.

  8. Magnetic pulse compression circuits for plasma devices

    Energy Technology Data Exchange (ETDEWEB)

    Georgescu, N; Zoita, V; Presura, R [Inst. of Physics and Technology of Radiation Devices, Bucharest (Romania)

    1997-12-31

    Two magnetic pulse compression circuits (MPCC), for two different plasma devices, are presented. The first is a 20 J/pulse, 3-stage circuit designed to trigger a low pressure discharge. The circuit has 16-18 kV working voltage, and 200 nF in each stage. The saturable inductors are realized with toroidal 25 {mu}m strip-wound cores, made of a Fe-Ni alloy, with 1.5 T saturation induction. The total magnetic volume is around 290 cm{sup 3}. By using a 25 kV/1 A thyratron as a primary switch, the time compression is from 3.5 {mu}s to 450 ns, in a short-circuit load. The second magnetic pulser is a 200 J/pulse circuit, designed to drive a high average power plasma focus soft X-ray source, for X-ray microlithography as the main application. The 3-stage pulser should supply a maximum load current of 100 kA with a rise-time of 250 - 300 ns. The maximum pulse voltage applied on the plasma discharge chamber is around 20 - 25 kV. The three saturable inductors in the circuit are made of toroidal strip-wound cores with METGLAS 2605 CO amorphous alloy as the magnetic material. The total, optimized mass of the magnetic material is 34 kg. The maximum repetition rate is limited at 100 Hz by the thyratron used in the first stage of the circuit, the driver supplying to the load about 20 kW average power. (author). 1 tab., 3 figs., 3 refs.

  9. Small circuits for cryptography.

    Energy Technology Data Exchange (ETDEWEB)

    Torgerson, Mark Dolan; Draelos, Timothy John; Schroeppel, Richard Crabtree; Miller, Russell D.; Anderson, William Erik

    2005-10-01

    This report examines a number of hardware circuit design issues associated with implementing certain functions in FPGA and ASIC technologies. Here we show circuit designs for AES and SHA-1 that have an extremely small hardware footprint, yet show reasonably good performance characteristics as compared to the state of the art designs found in the literature. Our AES performance numbers are fueled by an optimized composite field S-box design for the Stratix chipset. Our SHA-1 designs use register packing and feedback functionalities of the Stratix LE, which reduce the logic element usage by as much as 72% as compared to other SHA-1 designs.

  10. Silicon integrated circuit process

    International Nuclear Information System (INIS)

    Lee, Jong Duck

    1985-12-01

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  11. Primer printed circuit boards

    CERN Document Server

    Argyle, Andrew

    2009-01-01

    Step-by-step instructions for making your own PCBs at home. Making your own printed circuit board (PCB) might seem a daunting task, but once you master the steps, it's easy to attain professional-looking results. Printed circuit boards, which connect chips and other components, are what make almost all modern electronic devices possible. PCBs are made from sheets of fiberglass clad with copper, usually in multiplelayers. Cut a computer motherboard in two, for instance, and you'll often see five or more differently patterned layers. Making boards at home is relatively easy

  12. Silicon integrated circuit process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Duck

    1985-12-15

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  13. Circuit design for reliability

    CERN Document Server

    Cao, Yu; Wirth, Gilson

    2015-01-01

    This book presents physical understanding, modeling and simulation, on-chip characterization, layout solutions, and design techniques that are effective to enhance the reliability of various circuit units.  The authors provide readers with techniques for state of the art and future technologies, ranging from technology modeling, fault detection and analysis, circuit hardening, and reliability management. Provides comprehensive review on various reliability mechanisms at sub-45nm nodes; Describes practical modeling and characterization techniques for reliability; Includes thorough presentation of robust design techniques for major VLSI design units; Promotes physical understanding with first-principle simulations.

  14. Electronic circuits fundamentals & applications

    CERN Document Server

    Tooley, Mike

    2015-01-01

    Electronics explained in one volume, using both theoretical and practical applications.New chapter on Raspberry PiCompanion website contains free electronic tools to aid learning for students and a question bank for lecturersPractical investigations and questions within each chapter help reinforce learning Mike Tooley provides all the information required to get to grips with the fundamentals of electronics, detailing the underpinning knowledge necessary to appreciate the operation of a wide range of electronic circuits, including amplifiers, logic circuits, power supplies and oscillators. The

  15. Pre-assembling electric circuits of braided conductors

    International Nuclear Information System (INIS)

    Mercado Gomez, Martin Elias

    1999-01-01

    The present article has for object to give to know an innovative concept of pre-assembling electric circuits for distribution of normal and regulated power, to the work position like integral subsystems of the calls intelligent buildings

  16. [Work accidents and automatic circuit reclosers in the electricity sector: beyond the immediate causes].

    Science.gov (United States)

    Silva, Alessandro Jose Nunes da; Almeida, Ildeberto Muniz de; Vilela, Rodolfo Andrade de Gouveia; Mendes, Renata Wey Berti; Hurtado, Sandra Lorena Beltran

    2018-05-10

    The Brazilian electricity sector has recorded high work-related mortality rates that have been associated with outsourcing, used to cut costs. In order to decrease the power outage time for consumers, the industry adopted the automatic circuit recloser as the technical solution. The device has hazardous implications for maintenance workers. The aim of this study was to analyze the origins and consequences of work accidents in power systems with automatic circuit recloser, using the Accident Analysis and Prevention (AAP) model. The AAP model was used to investigate two work accidents, aimed to explore the events' organizational origins. Case 1 - when changing a deenergized secondary line, a worker received a shock from the energized primary cable (13.8kV). The system reclosed three times, causing severe injury to the worker (amputation of a lower limb). Case 2 - a fatal work accident occurred during installation of a new crosshead on a partially insulated energized line. The tip of a metal cross arm section strap touched the energized secondary line and electrocuted the maintenance operator. The circuit breaker component of the automatic circuit recloser failed. The analyses revealed how business management logic can participate in the root causes of work accidents through failures in maintenance management, outsourced workforce management, and especially safety management in systems with reclosers. Decisions to adopt automation to guarantee power distribution should not overlook the risks to workers in overhead power lines or fail to acknowledge the importance of ensuring safe conditions.

  17. ESD analog circuits and design

    CERN Document Server

    Voldman, Steven H

    2014-01-01

    A comprehensive and in-depth review of analog circuit layout, schematic architecture, device, power network and ESD design This book will provide a balanced overview of analog circuit design layout, analog circuit schematic development, architecture of chips, and ESD design.  It will start at an introductory level and will bring the reader right up to the state-of-the-art. Two critical design aspects for analog and power integrated circuits are combined. The first design aspect covers analog circuit design techniques to achieve the desired circuit performance. The second and main aspect pres

  18. Unstable oscillators based hyperchaotic circuit

    DEFF Research Database (Denmark)

    Murali, K.; Tamasevicius, A.; G. Mykolaitis, A.

    1999-01-01

    A simple 4th order hyperchaotic circuit with unstable oscillators is described. The circuit contains two negative impedance converters, two inductors, two capacitors, a linear resistor and a diode. The Lyapunov exponents are presented to confirm hyperchaotic nature of the oscillations in the circ...... in the circuit. The performance of the circuit is investigated by means of numerical integration of appropriate differential equations, PSPICE simulations, and hardware experiment.......A simple 4th order hyperchaotic circuit with unstable oscillators is described. The circuit contains two negative impedance converters, two inductors, two capacitors, a linear resistor and a diode. The Lyapunov exponents are presented to confirm hyperchaotic nature of the oscillations...

  19. The test of VLSI circuits

    Science.gov (United States)

    Baviere, Ph.

    Tests which have proven effective for evaluating VLSI circuits for space applications are described. It is recommended that circuits be examined after each manfacturing step to gain fast feedback on inadequacies in the production system. Data from failure modes which occur during operational lifetimes of circuits also permit redefinition of the manufacturing and quality control process to eliminate the defects identified. Other tests include determination of the operational envelope of the circuits, examination of the circuit response to controlled inputs, and the performance and functional speeds of ROM and RAM memories. Finally, it is desirable that all new circuits be designed with testing in mind.

  20. Electronic Circuit Analysis Language (ECAL)

    Science.gov (United States)

    Chenghang, C.

    1983-03-01

    The computer aided design technique is an important development in computer applications and it is an important component of computer science. The special language for electronic circuit analysis is the foundation of computer aided design or computer aided circuit analysis (abbreviated as CACD and CACA) of simulated circuits. Electronic circuit analysis language (ECAL) is a comparatively simple and easy to use circuit analysis special language which uses the FORTRAN language to carry out the explanatory executions. It is capable of conducting dc analysis, ac analysis, and transient analysis of a circuit. Futhermore, the results of the dc analysis can be used directly as the initial conditions for the ac and transient analyses.

  1. An integrated circuit switch

    Science.gov (United States)

    Bonin, E. L.

    1969-01-01

    Multi-chip integrated circuit switch consists of a GaAs photon-emitting diode in close proximity with S1 phototransistor. A high current gain is obtained when the transistor has a high forward common-emitter current gain.

  2. Automatic sweep circuit

    International Nuclear Information System (INIS)

    Keefe, D.J.

    1980-01-01

    An automatically sweeping circuit for searching for an evoked response in an output signal in time with respect to a trigger input is described. Digital counters are used to activate a detector at precise intervals, and monitoring is repeated for statistical accuracy. If the response is not found then a different time window is examined until the signal is found

  3. Automatic sweep circuit

    Science.gov (United States)

    Keefe, Donald J.

    1980-01-01

    An automatically sweeping circuit for searching for an evoked response in an output signal in time with respect to a trigger input. Digital counters are used to activate a detector at precise intervals, and monitoring is repeated for statistical accuracy. If the response is not found then a different time window is examined until the signal is found.

  4. "Printed-circuit" rectenna

    Science.gov (United States)

    Dickinson, R. M.

    1977-01-01

    Rectifying antenna is less bulky structure for absorbing transmitted microwave power and converting it into electrical current. Printed-circuit approach, using microstrip technology and circularly polarized antenna, makes polarization orientation unimportant and allows much smaller arrays for given performance. Innovation is particularly useful with proposed electric vehicles powered by beam microwaves.

  5. Het onzichtbare circuit

    NARCIS (Netherlands)

    Nauta, Bram

    2013-01-01

    De chip, of geïntegreerde schakeling, heeft in een razend tempo ons leven ingrijpend veranderd. Het lijkt zo vanzelfsprekend dat er weer een nieuwe generatie smartphones, tablets of computers is. Maar dat is het niet. Prof.dr.ir. Bram Nauta, hoogleraar Integrated Circuit Design, laat in zijn rede

  6. Voltage regulating circuit

    NARCIS (Netherlands)

    2005-01-01

    A voltage regulating circuit comprising a rectifier (2) for receiving an AC voltage (Vmains) and for generating a rectified AC voltage (vrec), and a capacitor (3) connected in parallel with said rectified AC voltage for providing a DC voltage (VDC) over a load (5), characterized by a unidirectional

  7. Streaming Reduction Circuit

    NARCIS (Netherlands)

    Gerards, Marco Egbertus Theodorus; Kuper, Jan; Kokkeler, Andre B.J.; Molenkamp, Egbert

    2009-01-01

    Reduction circuits are used to reduce rows of floating point values to single values. Binary floating point operators often have deep pipelines, which may cause hazards when many consecutive rows have to be reduced. We present an algorithm by which any number of consecutive rows of arbitrary lengths

  8. A Magnetic Circuit Demonstration.

    Science.gov (United States)

    Vanderkooy, John; Lowe, June

    1995-01-01

    Presents a demonstration designed to illustrate Faraday's, Ampere's, and Lenz's laws and to reinforce the concepts through the analysis of a two-loop magnetic circuit. Can be made dramatic and challenging for sophisticated students but is suitable for an introductory course in electricity and magnetism. (JRH)

  9. Analysis of emergency operating procedures effectiveness for core damage prevention using computer code RELAP for nuclear power plants with VVER-1000/B-320 in reference to primary to secondary circuit leak with external power loss and BRU-A stuck open failure

    International Nuclear Information System (INIS)

    Arkhangelski, L.; Sheveliov, D. V.

    1999-01-01

    This report presents analysis of development emergency operating procedures effectiveness for possible accident on nuclear power plant with WWER-1000 reactor type. Accident initiating event is the primary to secondary circuit leak caused by steam generator primary cover lift-up. In according to conservative assumptions the following additional failures were considered: dump valve BRU-A stuck open failure; loss of external power. The results of this work are represented as a comparative analysis of two possible ways of accident evolution: according to functioning automatic safety systems responses; according to accident management based on development emergency operating procedures with operator intervention. Developed emergency operating procedures assure the following significant goals to mitigate accident sequences: optimal use of ECCS water inventory; severe core damage prevention; mitigation of environment radioactive contamination. (authors)

  10. Circuit for Communication Over Power Lines

    Science.gov (United States)

    Krasowski, Michael J.; Prokop, Normal F.; Greer, Lawrence C., III; Nappier, Jennifer

    2011-01-01

    Many distributed systems share common sensors and instruments along with a common power line supplying current to the system. A communication technique and circuit has been developed that allows for the simple inclusion of an instrument, sensor, or actuator node within any system containing a common power bus. Wherever power is available, a node can be added, which can then draw power for itself, its associated sensors, and actuators from the power bus all while communicating with other nodes on the power bus. The technique modulates a DC power bus through capacitive coupling using on-off keying (OOK), and receives and demodulates the signal from the DC power bus through the same capacitive coupling. The circuit acts as serial modem for the physical power line communication. The circuit and technique can be made of commercially available components or included in an application specific integrated circuit (ASIC) design, which allows for the circuit to be included in current designs with additional circuitry or embedded into new designs. This device and technique moves computational, sensing, and actuation abilities closer to the source, and allows for the networking of multiple similar nodes to each other and to a central processor. This technique also allows for reconfigurable systems by adding or removing nodes at any time. It can do so using nothing more than the in situ power wiring of the system.

  11. Filament supply circuit for particle accelerator

    International Nuclear Information System (INIS)

    Thompson, C.C. Jr.; Malone, H.F.

    1975-01-01

    In a particle accelerator of the type employing ac primary power and a voltage multiplication apparatus to achieve the required high dc accelerating voltage, a filament supply circuit is powered by a portion of the ac primary power appearing at the last stage of the voltage multiplier. This ac power is applied across a voltage regulator circuit in the form of two zener diodes connected back to back. The threshold of the zeners is below the lowest peak-to-peak voltage of the ac voltage, so that the regulated voltage remains constant for all settings of the adjustable acceleration voltage. The regulated voltage is coupled through an adjustable resistor and an impedance-matching transformer to the accelerator filament. (auth)

  12. 30 CFR 75.802 - Protection of high-voltage circuits extending underground.

    Science.gov (United States)

    2010-07-01

    ...-Voltage Distribution § 75.802 Protection of high-voltage circuits extending underground. (a) Except as... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protection of high-voltage circuits extending... which shall be grounded through a suitable resistor at the source transformers, and a grounding circuit...

  13. Arrival time distributions of electrons in air showers with primary energies above 10 (18)eV observed at 900m above sea level

    Science.gov (United States)

    Kakimoto, F.; Tsuchimoto, I.; Enoki, T.; Suga, K.; Nishi, K.

    1985-01-01

    Detection of air showers with primary energies above 10 to the 19th power eV with sufficient statistics is extremely important in an astrophysical aspect related to the Greisen cut off and the origin of such high energy cosmic rays. Recently, a method is proposed to observe such giant air showers by measuring the arrival time distributions of air-shower particles at large core distances with a mini array. Experiments to measure the arrival time distributions of muons were started in 1981 and those of electrons in early 1983 in the Akeno air-shower array (930 gcm cm squared atmospheric depth, 900m above sea level). During the time of observation, the detection area of the Akeno array was expanded from 1 sq km to sq km in 1982 and to 20 sq km in 1984. Now the arrival time distribution of electrons and muons can be measured for showers with primary energies above 1019eV at large core distances.

  14. The LMT circuit and SPICE

    DEFF Research Database (Denmark)

    Lindberg, Erik; Murali, K.; Tamacevicius, Arunas

    2006-01-01

    The state equations of the LMT circuit are modeled as a dedicated analogue computer circuit and solved by means of PSpice. The nonlinear part of the system is studied. Problems with the PSpice program are presented....

  15. Resistor Combinations for Parallel Circuits.

    Science.gov (United States)

    McTernan, James P.

    1978-01-01

    To help simplify both teaching and learning of parallel circuits, a high school electricity/electronics teacher presents and illustrates the use of tables of values for parallel resistive circuits in which total resistances are whole numbers. (MF)

  16. Detecting short circuits during assembly

    Science.gov (United States)

    Deboo, G. J.

    1980-01-01

    Detector circuit identifies shorts between bus bars of electronic equipment being wired. Detector sounds alarm and indicates which planes are shorted. Power and ground bus bars are scanned continuously until short circuit occurs.

  17. Exploring Distributed Energy Alternatives to Electrical Distribution Grid Expansion in Souhern California Edison Service Territory

    Energy Technology Data Exchange (ETDEWEB)

    Stovall, Therese K [ORNL; Kingston, Tim [Gas Technology Institute

    2005-12-01

    Distributed energy (DE) technologies have received much attention for the energy savings and electric power reliability assurances that may be achieved by their widespread adoption. Fueling the attention have been the desires to globally reduce greenhouse gas emissions and concern about easing power transmission and distribution system capacity limitations and congestion. However, these benefits may come at a cost to the electric utility companies in terms of lost revenue and concerns with interconnection on the distribution system. This study assesses the costs and benefits of DE to both consumers and distribution utilities and expands upon a precursory study done with Detroit Edison (DTE)1, by evaluating the combined impact of DE, energy-efficiency, photovoltaics (a use of solar energy), and demand response that will shape the grid of the future. This study was funded by the U.S. Department of Energy (DOE), Gas Research Institute (GRI), American Electric Power (AEP), and Gas Technology Institute's (GTI) Distributed Energy Collaborative Program (DECP). It focuses on two real Southern California Edison (SCE) circuits, a 13 MW suburban circuit fictitiously named Justice on the Lincoln substation, and an 8 MW rural circuit fictitiously named Prosper on the Washington Substation. The primary objectives of the study were threefold: (1) Evaluate the potential for using advanced energy technologies, including DE, energy-efficiency (EE), demand response, electricity storage, and photovoltaics (PV), to reshape electric load curves by reducing peak demand, for real circuits. (2) Investigate the potential impact on guiding technology deployment and managing operation in a way that benefits both utilities and their customers by: (a) Improving grid load factor for utilities; (b) Reducing energy costs for customers; and (c) Optimizing electric demand growth. (3) Demonstrate benefits by reporting on a recently installed advanced energy system at a utility customer site

  18. Distribution of binding sites for the plant lectin Ulex europaeus agglutinin I on primary sensory neurones in seven different mammalian species.

    Science.gov (United States)

    Gerke, Michelle B; Plenderleith, Mark B

    2002-01-01

    There is an increasing body of evidence to suggest that different functional classes of neurones express characteristic cell-surface carbohydrates. Previous studies have shown that the plant lectin Ulex europaeus agglutinin-I (UEA) binds to a population of small to medium diameter primary sensory neurones in rabbits and humans. This suggests that a fucose-containing glycoconjugate may be expressed by nociceptive primary sensory neurones. In order to determine the extent to which this glycoconjugate is expressed by other species, in the current study, we have examined the distribution of UEA-binding sites on primary sensory neurones in seven different mammals. Binding sites for UEA were associated with the plasma membrane and cytoplasmic granules of small to medium dorsal root ganglion cells and their axon terminals in laminae I-III of the grey matter of the spinal cord, in the rabbit, cat and marmoset monkey. However, no binding was observed in either the dorsal root ganglia or spinal cord in the mouse, rat, guinea pig or flying fox. These results indicate an inter-species variation in the expression of cell-surface glycoconjugates on mammalian primary sensory neurones.

  19. Net primary productivity distribution in the BOREAS region from a process model using satellite and surface data

    Science.gov (United States)

    Liu, J.; Chen, J. M.; Cihlar, J.; Chen, W.

    1999-11-01

    The purpose of this paper is to upscale tower measurements of net primary productivity (NPP) to the Boreal Ecosystem-Atmosphere Study (BOREAS) study region by means of remote sensing and modeling. The Boreal Ecosystem Productivity Simulator (BEPS) with a new daily canopy photosynthesis model was first tested in one coniferous and one deciduous site. The simultaneous CO2 flux measurements above and below the tree canopy made it possible to isolate daily net primary productivity of the tree canopy for model validation. Soil water holding capacity and gridded daily meteorological data for the region were used as inputs to BEPS, in addition to 1 km resolution land cover and leaf area index (LAI) maps derived from the advanced very high resolution radiometer (AVHRR) data. NPP statistics for the various cover types in the BOREAS region and in the southern study area (SSA) and the northern study area (NSA) are presented. Strong dependence of NPP on LAI was found for the three major cover types: coniferous forest, deciduous forest and cropland. Since BEPS can compute total photosynthetically active radiation absorbed by the canopy in each pixel, light use efficiencies for NPP and gross primary productivity could also be analyzed. From the model results, the following area-averaged statistics were obtained for 1994: (1) mean NPP for the BOREAS region of 217 g C m-2 yr-1; (2) mean NPP of forests (excluding burnt areas in the region) equal to 234 g C m-2 yr-1; (3) mean NPP for the SSA and the NSA of 297 and 238 g C m-2 yr-1, respectively; and (4) mean light use efficiency for NPP equal to 0.40, 0.20, and 0.33 g C (MJ APAR)-1 for deciduous forest, coniferous forest, and crops, respectively.

  20. MOS voltage automatic tuning circuit

    OpenAIRE

    李, 田茂; 中田, 辰則; 松本, 寛樹

    2004-01-01

    Abstract ###Automatic tuning circuit adjusts frequency performance to compensate for the process variation. Phase locked ###loop (PLL) is a suitable oscillator for the integrated circuit. It is a feedback system that compares the input ###phase with the output phase. It can make the output frequency equal to the input frequency. In this paper, PLL ###fomed of MOSFET's is presented.The presented circuit consists of XOR circuit, Low-pass filter and Relaxation ###Oscillator. On PSPICE simulation...

  1. Behavioral synthesis of asynchronous circuits

    DEFF Research Database (Denmark)

    Nielsen, Sune Fallgaard

    2005-01-01

    This thesis presents a method for behavioral synthesis of asynchronous circuits, which aims at providing a synthesis flow which uses and tranfers methods from synchronous circuits to asynchronous circuits. We move the synchronous behavioral synthesis abstraction into the asynchronous handshake...... is idle. This reduces unnecessary switching activity in the individual functional units and therefore the energy consumption of the entire circuit. A collection of behavioral synthesis algorithms have been developed allowing the designer to perform time and power constrained design space exploration...

  2. Selected collection of circuit drawings

    International Nuclear Information System (INIS)

    1977-01-01

    The many electronics circuits have been constracted in the Electronics Shop for use in nuclear experiments or other purposes of this Institute. The types of these circuits amount to about 500 items in total since 1968. This report describes the electronics circuit diagrams selected from this collection. The circuit details are not presented in this report, because these are already been published in the other technical reports. (auth.)

  3. Diode, transistor & fet circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Diode, Transistor and FET Circuits Manual is a handbook of circuits based on discrete semiconductor components such as diodes, transistors, and FETS. The book also includes diagrams and practical circuits. The book describes basic and special diode characteristics, heat wave-rectifier circuits, transformers, filter capacitors, and rectifier ratings. The text also presents practical applications of associated devices, for example, zeners, varicaps, photodiodes, or LEDs, as well as it describes bipolar transistor characteristics. The transistor can be used in three basic amplifier configuration

  4. Analysis of Bernstein's factorization circuit

    NARCIS (Netherlands)

    Lenstra, A.K.; Shamir, A.; Tomlinson, J.; Tromer, E.; Zheng, Y.

    2002-01-01

    In [1], Bernstein proposed a circuit-based implementation of the matrix step of the number field sieve factorization algorithm. These circuits offer an asymptotic cost reduction under the measure "construction cost x run time". We evaluate the cost of these circuits, in agreement with [1], but argue

  5. High voltage MOSFET switching circuit

    Science.gov (United States)

    McEwan, Thomas E.

    1994-01-01

    The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET.

  6. Experimental Study on Short Circuit Phenomena in Air Switch of Distribution Line due to Sparkover between Different Poles on Which One Surge Arrester of the Three Ones is Omitted

    Science.gov (United States)

    Sato, Tomoyuki; Uemura, Satoshi; Asakawa, Akira; Yokoyama, Shigeru; Honda, Hideki; Horikoshi, Kazuhiro

    In this study, we experimentally examined the possibility of the internal short circuit of an air switch due to the sparkover between different poles under the condition that no surge arrester exists in neighboring poles and one of three surge arresters is omitted at the pole with an air switch. Experiments at Shiobara Testing Yard and Akagi Testing Center of CRIEPI clarified the following. Fault current may flow via the grounding point of a pole with an air switch and that of the next pole on a different phase from grounded phase of the pole with an air switch. If the low-voltage wire, overhead ground wire or communication wire forms a short circuit between them, ultimately the air switch may burn out. Moreover Fault current continues even if the length of the short-circuit between different poles is increased. Although the increase of the short-circuit length results in the increase of wire impedance, the amount of increase is still small compared with source impedance.

  7. Neuromorphic Silicon Neuron Circuits

    Science.gov (United States)

    Indiveri, Giacomo; Linares-Barranco, Bernabé; Hamilton, Tara Julia; van Schaik, André; Etienne-Cummings, Ralph; Delbruck, Tobi; Liu, Shih-Chii; Dudek, Piotr; Häfliger, Philipp; Renaud, Sylvie; Schemmel, Johannes; Cauwenberghs, Gert; Arthur, John; Hynna, Kai; Folowosele, Fopefolu; Saighi, Sylvain; Serrano-Gotarredona, Teresa; Wijekoon, Jayawan; Wang, Yingxue; Boahen, Kwabena

    2011-01-01

    Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain–machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance-based Hodgkin–Huxley models to bi-dimensional generalized adaptive integrate and fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips. PMID:21747754

  8. Neuromorphic silicon neuron circuits

    Directory of Open Access Journals (Sweden)

    Giacomo eIndiveri

    2011-05-01

    Full Text Available Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain-machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance based Hodgkin-Huxley models to bi-dimensional generalized adaptive Integrate and Fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips.

  9. Integrated circuit structure

    International Nuclear Information System (INIS)

    1981-01-01

    The invention describes the fabrication of integrated circuit structures, such as read-only memory components of field-effect transistors, which may be fabricated and then maintained in inventory, and later selectively modified in accordance with a desired pattern. It is claimed that MOS depletion-mode devices in accordance with the invention can be fabricated at lower cost and at higher yields. (U.K.)

  10. Integrated Circuit Immunity

    Science.gov (United States)

    Sketoe, J. G.; Clark, Anthony

    2000-01-01

    This paper presents a DOD E3 program overview on integrated circuit immunity. The topics include: 1) EMI Immunity Testing; 2) Threshold Definition; 3) Bias Tee Function; 4) Bias Tee Calibration Set-Up; 5) EDM Test Figure; 6) EMI Immunity Levels; 7) NAND vs. and Gate Immunity; 8) TTL vs. LS Immunity Levels; 9) TP vs. OC Immunity Levels; 10) 7805 Volt Reg Immunity; and 11) Seventies Chip Set. This paper is presented in viewgraph form.

  11. Integrated coincidence circuits

    International Nuclear Information System (INIS)

    Borejko, V.F.; Grebenyuk, V.M.; Zinov, V.G.

    1976-01-01

    The description is given of two coincidence units employing integral circuits in the VISHNYA standard. The units are distinguished for the coincidence selection element which is essentially a combination of a tunnel diode and microcircuits. The output fast response of the units is at least 90 MHz in the mode of the output signal unshaped in duration and 50 MHz minimum in the mode of the output signal shaping. The resolution time of the units is dependent upon the duration of input signals

  12. Distribution of throughfall and stemflow in multi-strata agroforestry, perennial monoculture, fallow and primary forest in central Amazonia, Brazil

    Science.gov (United States)

    Schroth, Götz; Ferreira da Silva, Luciana; Wolf, Marc-Andree; Geraldes Teixeira, Wenceslau; Zech, Wolfgang

    1999-07-01

    The partitioning of rain water into throughfall, stemflow and interception loss when passing through plant canopies depends on properties of the respective plant species, such as leaf area and branch angles. In heterogeneous vegetation, such as tropical forest or polycultural systems, the presence of different plant species may consequently result in a mosaic of situations with respect to quantity and quality of water inputs into the soil. As these processes influence not only the water availability for the plants, but also water infiltration and nutrient leaching, the understanding of plant effects on the repartitioning of rain water may help in the optimization of land use systems and management practices. We measured throughfall and stemflow in a perennial polyculture (multi-strata agroforestry), monocultures of peach palm (Bactris gasipaes) for fruit and for palmito, a monoculture of cupuaçu (Theobroma grandiflorum), spontaneous fallow and primary forest during one year in central Amazonia, Brazil. The effect on rain water partitioning was measured separately for four useful tree species in the polyculture and for two tree species in the primary forest. Throughfall at two stem distances, and stemflow, differed significantly between tree species, resulting in pronounced spatial patterns of water input into the soil in the polyculture system. For two tree species, peach palm for fruit (Bactris gasipaes) and Brazil nut trees (Bertholletia excelsa), the water input into the soil near the stem was significantly higher than the open-area rainfall. This could lead to increased nutrient leaching when fertilizer is applied close to the stem of these trees. In the primary forest, such spatial patterns could also be detected, with significantly higher water input near a palm (Oenocarpus bacaba) than near a dicotyledonous tree species (Eschweilera sp.). Interception losses were 6·4% in the polyculture, 13·9 and 12·3% in the peach palm monocultures for fruit and for

  13. Semiconductor integrated circuits

    International Nuclear Information System (INIS)

    Michel, A.E.; Schwenker, R.O.; Ziegler, J.F.

    1979-01-01

    An improved method involving ion implantation to form non-epitaxial semiconductor integrated circuits. These are made by forming a silicon substrate of one conductivity type with a recessed silicon dioxide region extending into the substrate and enclosing a portion of the silicon substrate. A beam of ions of opposite conductivity type impurity is directed at the substrate at an energy and dosage level sufficient to form a first region of opposite conductivity within the silicon dioxide region. This impurity having a concentration peak below the surface of the substrate forms a region of the one conductivity type which extends from the substrate surface into the first opposite type region to a depth between the concentration peak and the surface and forms a second region of opposite conductivity type. The method, materials and ion beam conditions are detailed. Vertical bipolar integrated circuits can be made this way when the first opposite type conductivity region will function as a collector. Also circuits with inverted bipolar devices when this first region functions as a 'buried'' emitter region. (U.K.)

  14. Naloxone Distribution and Training for Patients with High-Risk Opioid Use in a Veterans Affairs Community-Based Primary Care Clinic.

    Science.gov (United States)

    Raffel, Katie E; Beach, Leila Y; Lin, John; Berchuck, Jacob E; Abram, Shelly; Markle, Elizabeth; Patel, Shalini

    2018-03-30

    Naloxone distribution has historically been implemented in a community-based, expanded public health model; however, there is now a need to further explore primary care clinic-based naloxone delivery to effectively address the nationwide opioid epidemic. To create a general medicine infrastructure to identify patients with high-risk opioid use and provide 25% of this population with naloxone autoinjector prescription and training within a 6-month period. The quality improvement study was conducted at an outpatient clinic serving 1238 marginally housed veterans with high rates of comorbid substance use and mental health disorders. Patients at high risk of opioid-related adverse events were identified using the Stratification Tool for Opioid Risk Management and were contacted to participate in a one-on-one, 15-minute, hands-on naloxone training led by nursing staff. The number of patients identified at high risk and rates of naloxone training/distribution. There were 67 patients identified as having high-risk opioid use. None of these patients had been prescribed naloxone at baseline. At the end of the intervention, 61 patients (91%) had been trained in the use of naloxone. Naloxone was primarily distributed by licensed vocational nurses (42/61, 69%). This study demonstrates the feasibility of high-risk patient identification and of a primary care-based and nursing-championed naloxone distribution model. This delivery model has the potential to provide access to naloxone to a population of patients with opioid use who may not be engaged in mental health or specialty care.

  15. Probabilistic model for primary distribution networks performance evaluation; Modelo probabilistico para avaliacao do desempenho de redes de distribuicao primaria

    Energy Technology Data Exchange (ETDEWEB)

    Valente, Andre Luiz de Carvalho

    1997-07-01

    A method for performance evaluation of primary feeders with respect to voltage drop, loss and level of reliability to use, specially in studies of investment planning is focused. The probabilistic model is the chronological minimum length tree. The work consists of: analysis of model; proposition of modifications in model necessary to brazilian electrical sector reality, introducing parameter representing the load density; model adaptation to reliability studies, with evaluation of principal indicators in use in the country; development of software for microcomputer; the simulation of some cases with the software; based in the results, attainment of laws to facilitate the use of model. Eventually, the conclusions are made with considerations about possible applications of the method and research topics for further developments are settled. (author)

  16. Anomalous Distributions of Primary Cosmic Rays as Evidence for Time-dependent Particle Acceleration in Supernova Remnants

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yiran; Liu, Siming; Yuan, Qiang, E-mail: liusm@pmo.ac.cn [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2017-07-20

    Recent precise measurements of cosmic-ray (CR) spectra show that the energy distribution of protons is softer than those of heavier nuclei, and there are spectral hardenings for all nuclear compositions above ∼200 GV. Models proposed for these anomalies generally assume steady-state solutions of the particle acceleration process. We show that if the diffusion coefficient has a weak dependence on the particle rigidity near shock fronts of supernova remnants (SNRs), time-dependent solutions of the linear diffusive shock acceleration at two stages of SNR evolution can naturally account for these anomalies. The high-energy component of CRs is dominated by acceleration in the free expansion and adiabatic phases with enriched heavy elements and a high shock speed. The low-energy component may be attributed to acceleration by slow shocks propagating in dense molecular clouds with low metallicity in the radiative phase. Instead of a single power-law distribution, the spectra of time-dependent solutions soften gradually with the increase of energy, which may be responsible for the “knee” of CRs.

  17. Interface Circuit For Printer Port

    Science.gov (United States)

    Tucker, Jerry H.; Yadlowsky, Ann B.

    1991-01-01

    Electronic circuit, called printer-port interface circuit (PPI) developed to overcome certain disadvantages of previous methods for connecting IBM PC or PC-compatible computer to other equipment. Has both reading and writing modes of operation. Very simple, requiring only six integrated circuits. Provides for moderately fast rates of transfer of data and uses existing unmodified circuit card in IBM PC. When used with appropriate software, circuit converts printer port on IBM PC, XT, AT, or compatible personal computer to general purpose, 8-bit-data, 16-bit address bus that connects to multitude of devices.

  18. Changes to the shuttle circuits

    CERN Multimedia

    GS Department

    2011-01-01

    To fit with passengers expectation, there will be some changes to the shuttle circuits as from Monday 10 October. See details on http://cern.ch/ShuttleService (on line on 7 October). Circuit No. 5 is cancelled as circuit No. 1 also stops at Bldg. 33. In order to guarantee shorter travel times, circuit No. 1 will circulate on Meyrin site only and circuit No. 2, with departures from Bldg. 33 and 500, on Prévessin site only. Site Services Section

  19. Testing methods of gaseous admixtures in HLMC circuits

    International Nuclear Information System (INIS)

    Shelemet'ev, V.M.; Martynov, P.N.; Askhadullin, R.Sh.; Storozhenko, A.N.; Sadovnichij, R.P.; Ivanov, I.I.

    2014-01-01

    Control of gas phase is the effective method for state diagnostics of circuit of nuclear power facilities with heavy liquid metal coolants. Use of developing in IPPE solid electrolyte and conductometric oxygen and hydrogen sensors, which are set directly in gas system of the primary circuit, allows to maintain continuously control of oxygen and hydrogen content as well as operational efficiency and accuracy of these parameters determination under various situations related with oxygen and hydrogen insertion into circuit. Sensors ensure long-term safe operation under extreme conditions of high temperatures, pressures, humidity, etc., and are advanced devices for application in nuclear power facilities with heavy liquid metal coolants [ru

  20. Thermionic integrated circuits: electronics for hostile environments

    International Nuclear Information System (INIS)

    Lynn, D.K.; McCormick, J.B.; MacRoberts, M.D.J.; Wilde, D.K.; Dooley, G.R.; Brown, D.R.

    1985-01-01

    Thermionic integrated circuits combine vacuum tube technology with integrated circuit techniques to form integrated vacuum triode circuits. These circuits are capable of extended operation in both high-temperature and high-radiation environments