WorldWideScience

Sample records for forced circulation circuit

  1. Logic circuits from zero forcing.

    Science.gov (United States)

    Burgarth, Daniel; Giovannetti, Vittorio; Hogben, Leslie; Severini, Simone; Young, Michael

    We design logic circuits based on the notion of zero forcing on graphs; each gate of the circuits is a gadget in which zero forcing is performed. We show that such circuits can evaluate every monotone Boolean function. By using two vertices to encode each logical bit, we obtain universal computation. We also highlight a phenomenon of "back forcing" as a property of each function. Such a phenomenon occurs in a circuit when the input of gates which have been already used at a given time step is further modified by a computation actually performed at a later stage. Finally, we show that zero forcing can be also used to implement reversible computation. The model introduced here provides a potentially new tool in the analysis of Boolean functions, with particular attention to monotonicity. Moreover, in the light of applications of zero forcing in quantum mechanics, the link with Boolean functions may suggest a new directions in quantum control theory and in the study of engineered quantum spin systems. It is an open technical problem to verify whether there is a link between zero forcing and computation with contact circuits.

  2. Experimental study of natural circulation circuit

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  3. Experimental study of natural circulation circuit

    International Nuclear Information System (INIS)

    Lemos, Wanderley F.; Su, Jian; Faccini, Jose L.H.

    2011-01-01

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

  4. Experimental study of two-phase natural circulation circuit

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-01

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

  5. Experimental study of two-phase natural circulation circuit

    International Nuclear Information System (INIS)

    Lemos, Wanderley Freitas; Su, Jian; Faccini, Jose Luiz Horacio

    2012-01-01

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

  6. Steam generator of the forced circulation type

    International Nuclear Information System (INIS)

    Forestier, Jean; Leblanc, Bernard; Monteil, Marcel; Monteil, Pierre

    1977-01-01

    The steam generator described is of the forced circulation single passage type comprising an outer casing including a vertical generally cylindrical side ring, an internal skirt coaxial with the outer casing, the bottom of this skirt having a free edge separated from a bottom end closing the outer casing, a central tube plate extending horizontally near a top end, in opposition to the bottom end, a peripheral tube plate, parallel to the central plate and located in the annular space under this central plate, a bundle of J shaped tubes [fr

  7. Circuit Design of Surface Acoustic Wave Based Micro Force Sensor

    Directory of Open Access Journals (Sweden)

    Yuanyuan Li

    2014-01-01

    Full Text Available Pressure sensors are commonly used in industrial production and mechanical system. However, resistance strain, piezoresistive sensor, and ceramic capacitive pressure sensors possess limitations, especially in micro force measurement. A surface acoustic wave (SAW based micro force sensor is designed in this paper, which is based on the theories of wavelet transform, SAW detection, and pierce oscillator circuits. Using lithium niobate as the basal material, a mathematical model is established to analyze the frequency, and a peripheral circuit is designed to measure the micro force. The SAW based micro force sensor is tested to show the reasonable design of detection circuit and the stability of frequency and amplitude.

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

    International Nuclear Information System (INIS)

    Torres, Walmir M.; Macedo, Luiz A.; Sabundjian, Gaiane; Andrade, Delvonei A.; Umbehaun, Pedro E.; Conti, Thadeu N.; Mesquita, Roberto N.; Masotti, Paulo H.; Angelo, Gabriel

    2011-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  10. In-service diagnostics of main circulating circuit pipes of WWER nuclear power plants

    International Nuclear Information System (INIS)

    Svoboda, V.; Merta, J.; Merta, V.

    1982-01-01

    The application is discussed of the acoustic emission method for testing the integrity of the components of the main circulating circuit of the WWER 440 nuclear power plant. A description is given of the main circulating circuit and a stress analysis on the basis of strength computations considering operating modes is presented. An analysis is also presented of the possible damage of the pipe material as related to the application of the acoustic emission method for in-service inspection of the pipes. Certain practical problems of application are discussed. (author)

  11. Methodology for studies of natural circulation in closed circuits

    International Nuclear Information System (INIS)

    Araujo, Rafael de Oliveira Pessoa de

    2009-01-01

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

  12. Electronic zero-point fluctuation forces inside circuit components

    Science.gov (United States)

    Leonhardt, Ulf

    2018-01-01

    One of the most intriguing manifestations of quantum zero-point fluctuations are the van der Waals and Casimir forces, often associated with vacuum fluctuations of the electromagnetic field. We study generalized fluctuation potentials acting on internal degrees of freedom of components in electrical circuits. These electronic Casimir-like potentials are induced by the zero-point current fluctuations of any general conductive circuit. For realistic examples of an electromechanical capacitor and a superconducting qubit, our results reveal the possibility of tunable forces between the capacitor plates, or the level shifts of the qubit, respectively. Our analysis suggests an alternative route toward the exploration of Casimir-like fluctuation potentials, namely, by characterizing and measuring them as a function of parameters of the environment. These tunable potentials may be useful for future nanoelectromechanical and quantum technologies. PMID:29719863

  13. Electronic zero-point fluctuation forces inside circuit components.

    Science.gov (United States)

    Shahmoon, Ephraim; Leonhardt, Ulf

    2018-04-01

    One of the most intriguing manifestations of quantum zero-point fluctuations are the van der Waals and Casimir forces, often associated with vacuum fluctuations of the electromagnetic field. We study generalized fluctuation potentials acting on internal degrees of freedom of components in electrical circuits. These electronic Casimir-like potentials are induced by the zero-point current fluctuations of any general conductive circuit. For realistic examples of an electromechanical capacitor and a superconducting qubit, our results reveal the possibility of tunable forces between the capacitor plates, or the level shifts of the qubit, respectively. Our analysis suggests an alternative route toward the exploration of Casimir-like fluctuation potentials, namely, by characterizing and measuring them as a function of parameters of the environment. These tunable potentials may be useful for future nanoelectromechanical and quantum technologies.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

  15. Atlantic Meridional Overturning Circulation response to idealized external forcing

    Energy Technology Data Exchange (ETDEWEB)

    Park, W.; Latif, M. [Leibniz-Institut fuer Meereswissenschaften an der Universitaet Kiel, Kiel (Germany)

    2012-10-15

    The response of the Atlantic Meridional Overturning Circulation (AMOC) to idealized external (solar) forcing is studied in terms of the internal (unforced) AMOC modes with the Kiel Climate Model (KCM), a coupled atmosphere-ocean-sea ice general circulation model. The statistical investigation of KCM's internal AMOC variability obtained from a multi-millennial control run yields three distinct modes: a multi-decadal mode with a period of about 60 years, a quasi-centennial mode with a period of about 100 years and a multi-centennial mode with a period of about 300-400 years. Most variance is explained by the multi-centennial mode, and the least by the quasi-centennial mode. The solar constant varies sinusoidally with two different periods (100 and 60 years) in forced runs with KCM. The AMOC response to the external forcing is rather complex and nonlinear. It involves strong changes in the frequency structure of the variability. While the control run depicts multi-timescale behavior, the AMOC variability in the experiment with 100 year forcing period is channeled into a relatively narrow band centered near the forcing period. It is the quasi-centennial AMOC mode with a period of just under 100 years which is excited, although it is heavily damped in the control run. Thus, the quasi-centennial mode retains its period which does not correspond exactly to the forcing period. Surprisingly, the quasi-centennial mode is also most strongly excited when the forcing period is set to 60 years, the period of the multi-decadal mode which is rather prominent in the control run. It is largely the spatial structure of the forcing rather than its period that determines which of the three internal AMOC modes is excited. The results suggest that we need to understand the full modal structure of the internal AMOC variability in order to understand the circulation's response to external forcing. This could be a challenge for climate models: we cannot necessarily expect that the

  16. Thermo hydraulics of a steam boiler forced circulation

    International Nuclear Information System (INIS)

    Tucakovic, Dragan; Zivanovic, Titoslav; Stevanovic, Vladimir

    2006-01-01

    In order to minimize the dryout at the steam boiler furnace in the Thermal Power Plant Kolubara B, designed are inner rifled wall tubes. This type of tubes, with many spiral grooves cut into the bore, prevents film boiling and enables the nucleate boiling be still maintained under the condition of vapour quality being app. 1. To verify the choice of the rifled tubes instead of the cheaper, smooth tubes type being justified, analyzed is the change of the actual and critical vapour quality with the furnace height, under uniform and non-uniform heat flu through evaporator walls. Furthermore, made are hydraulic calculations for various steam boiler loads, in case of both rifled and smooth tubes types, with the purpose to check the rifles influence to pressure drop increase in comparison with the smooth tubes. Also, checked is the selection of the circulation pump. Key words: evaporator, forced circulation, rifled tubes, critical vapour quality, pressure drop

  17. MES lead bismuth forced circulation loop and test results

    International Nuclear Information System (INIS)

    Ono, Mikinori; Mine, Tatsuya; Kitano, Teruaki; Kamata, Kin-ya

    2003-01-01

    Liquid lead-bismuth is a promising material as future reactor coolant or intensive neutron source material for accelerator driven system (ADS). Mitsui Engineering and Shipbuilding Co., Ltd. (MES) completed lead-bismuth coolant (LBC) forced circulation loop in May 2001 and acquired engineering data on economizer, electro magnetic pump, electro magnetic flow meter and so on. For quality control of LBC, oxygen sensor and filtering element are developing using some hydrogen and moisture mixed gases. Structural materials corrosion test for accelerator driver system (ADS) will start soon. And thermal hydraulic test for ADS will start in tree years. (author)

  18. Capacitance sensor for void fraction measurement in a natural circulation refrigeration circuit

    International Nuclear Information System (INIS)

    Rocha, Marcelo S.; Cabral, Eduardo L.L.; Simoes-Moreira, Jose R.

    2009-01-01

    Natural circulation is widely used in nuclear reactors for residual heat refrigeration. In this work, a conductance probe is designed and constructed to measure the instantaneous bulk void fraction in a vertical tube section. This probe is installed in a natural circulation refrigeration loop designed to simulate a nuclear reactor primary refrigeration circuit. During the operation of the natural circulation loop several gas-liquid flow patterns are observed, including oscillatory flow. The instantaneous signal generated by the capacitance probe allows the calculation of the two-phase flow void fraction. The void fraction obtained by the probe will be compared with the theoretical void fraction calculated by the computational program RELAP5/MOD3.2.2 gamma. The probe design and electronics, as well as the previous results obtained are presented and discussed. (author)

  19. Widely Tunable On-Chip Microwave Circulator for Superconducting Quantum Circuits

    Science.gov (United States)

    Chapman, Benjamin J.; Rosenthal, Eric I.; Kerckhoff, Joseph; Moores, Bradley A.; Vale, Leila R.; Mates, J. A. B.; Hilton, Gene C.; Lalumière, Kevin; Blais, Alexandre; Lehnert, K. W.

    2017-10-01

    We report on the design and performance of an on-chip microwave circulator with a widely (GHz) tunable operation frequency. Nonreciprocity is created with a combination of frequency conversion and delay, and requires neither permanent magnets nor microwave bias tones, allowing on-chip integration with other superconducting circuits without the need for high-bandwidth control lines. Isolation in the device exceeds 20 dB over a bandwidth of tens of MHz, and its insertion loss is small, reaching as low as 0.9 dB at select operation frequencies. Furthermore, the device is linear with respect to input power for signal powers up to hundreds of fW (≈103 circulating photons), and the direction of circulation can be dynamically reconfigured. We demonstrate its operation at a selection of frequencies between 4 and 6 GHz.

  20. Performance Improvement of a Radioactive Forced Circulation Evaporator System

    International Nuclear Information System (INIS)

    Zaki, A.A.; Hala, A.A.; Othman, E.A.

    2016-01-01

    Evaporation is a proven method for treatment of liquid radioactive wastes providing both good decontamination and high concentration. In a radioactive waste treatment plant a forced circulation evaporator is used to reduce the volume of radioactive liquid wastes arising from different applications of nuclear industries. The safe operation, limiting the composition of the liquid radioactive waste at a prescribed value, with high performance efficiency, requires good control for the evaporator operating pressure and the level of liquid waste inside the separator part of the evaporator. The aim of this work was to improve the safety and performance of a forced-circulation evaporator used in a liquid radioactive wastes treatment plant. In this respect, a level controller system for this type of evaporator was designed, where proportional (P), proportional Integral (PI) and deadbeat response controllers for the separator level system were suggested. More over, an ideal 2×2(2 inputs and 2 outputs )de coupler controller for controlling the operating pressure and the product composition was developed. Computer results demonstrated that the deadbeat response has been success fully obtained from the developed separator control system. The maximum over shoot in the unit-step response curve was reduce d to 25 % and the settling time also was reduced to more than the half; about 26 minutes using Ziegler-Nichols tuning technique.The designed de coupling controller has been found effective in achieving a good trade-off between stability and performance

  1. Forced circulation type steam generator simulation code: HT4

    International Nuclear Information System (INIS)

    Okamoto, Masaharu; Tadokoro, Yoshihiro

    1982-08-01

    The purpose of this code is a understanding of dynamic characteristics of the steam generator, which is a component of High-temperature Heat Transfer Components Test Unit. This unit is a number 4th test section of Helium Engineering Demonstration Loop (HENDEL). Features of this report are as follows, modeling of the steam generator, a basic relationship for the continuity equation, numerical analysis techniques of a non-linear simultaneous equation and computer graphics output techniques. Forced circulation type steam generator with strait tubes and horizontal cut baffles, applied in this code, have be designed at the Over All System Design of the VHTRex. The code is for use with JAERI's digital computer FACOM M200. About 1.5 sec required for each time step reiteration, then about 40 sec cpu time required for a standard problem. (author)

  2. Radiological characterization of the main circulation circuit of the 1st unit at Ignalina NPP

    International Nuclear Information System (INIS)

    Poskas, P.; Zujus, R.; Brazauskaite, A. and others

    2003-01-01

    A preliminary assessment of the main circulation circuit (MCC) equipment contamination at the reactor final shut-down and analysis of the contamination variation with time are presented. In order to perform this assessment, data on MCC element characteristics, the coolant characteristics, the system operational conditions, etc. were collected. The modified computer code LLWAA-DECOM (Belgium) was used to determine contamination of the system elements. As a result, nuclide vectors and surface dose rates of deposits for every MCC element were determined. The modeling results were compared to the measurement results of the dose rates. (author)

  3. Dynamic simulation of a forced circulation evaporating system

    International Nuclear Information System (INIS)

    Lee, J.S.; Lee, K.J.

    1993-01-01

    A dynamic simulation program has been developed to simulate the forced circulation evaporating system of the Kori PWR Power Plant in Korea which is used to treat liquid waste containing boric acid. Energy and mass balances for the vapor and liquid phases are used to describe the interaction among system components such as the vapor body, heater jacket and condenser. In order to simulate entrainment carryover in the sieve tray column and wire mesh pad, Kister's and Carpenter-Othmer's correlations are adopted, respectively. A new correlation formula is also suggested to simulate the geometric effect of the vapor body. A fuzzy heuristic controller and conventional controllers such as P (proportional), PI (proportional-integral) and PID (proportional-integral-derivative) controls are incorporated to observe their responses to a given disturbance. The simulations show good agreement with the real operation data. It is also identified that the vapor velocity or flow rate in the sieve tray column determines the system decontamination factor (DF), and that the longer the vapor body is, the less entrainment carryover occurs out of the vapor body. In addition, the wire mesh pad is identified as maintaining very high deentrainment efficiency even though the vapor velocity may show large fluctuations. With respect to system control, the fuzzy heuristic controller approaches a new steady state faster than conventional controllers. Also the fuzzy controller maintains higher DF during transients and is stronger against time delay in the control components. (Author)

  4. Direct weakening of tropical circulations from masked CO2 radiative forcing.

    Science.gov (United States)

    Merlis, Timothy M

    2015-10-27

    Climate models robustly simulate weakened mean circulations of the tropical atmosphere in direct response to increased carbon dioxide (CO2). The direct response to CO2, defined by the response to radiative forcing in the absence of changes in sea surface temperature, affects tropical precipitation and tropical cyclone genesis, and these changes have been tied to the weakening of the mean tropical circulation. The mechanism underlying this direct CO2-forced circulation change has not been elucidated. Here, I demonstrate that this circulation weakening results from spatial structure in CO2's radiative forcing. In regions of ascending circulation, such as the intertropical convergence zone, the CO2 radiative forcing is reduced, or "masked," by deep-convective clouds and high humidity; in subsiding regions, such as the subtropics, the CO2 radiative forcing is larger because the atmosphere is drier and deep-convective clouds are infrequent. The spatial structure of the radiative forcing reduces the need for the atmosphere to transport energy. This, in turn, weakens the mass overturning of the tropical circulation. The previously unidentified mechanism is demonstrated in a hierarchy of atmospheric general circulation model simulations with altered radiative transfer to suppress the cloud masking of the radiative forcing. The mechanism depends on the climatological distribution of clouds and humidity, rather than uncertain changes in these quantities. Masked radiative forcing thereby offers an explanation for the robustness of the direct circulation weakening under increased CO2.

  5. Verification of RBMK-1500 reactor main circulation circuit model with Cathare V1.3L

    International Nuclear Information System (INIS)

    Jasiulevicius, A.

    2001-01-01

    Among other computer codes, French code CATHARE is also applied for RBMK reactor calculations. In this paper results of such application for Ignalina NPP reactor (RBMK-1500 type) main circulation circuit are presented. Three transients calculations were performed: all main circulation pumps (MCP) trip, trip of one main circulation pump and trip of one main circulation pump without a closure of check valve on the pump line. Calculation results were compared to data from the Ignalina NPP, where all these transients were recorded in the years 1986, 1996 and 1998. The presented studies prove the capability of the CATHARE code to treat thermal-hydraulic transients with a reactor scram in the RBMK, in case of single or multiple pump trips. However, the presented model needs further improvements in order to simulate loss of coolant accidents. For this reason, emergency core cooling system should be included in the model. Additional model improvement is also needed in order to gain more independent pressure behavior in both loops. Also, flow rates through the reactor channels should be modeled by dividing channels into several groups, referring to channel power (in RBMK power produced in a channel, located in different parts of the core is not the same). The point-neutron kinetic model of the CATHARE code is not suitable to predict transients when the reactor is operating at a nominal power level. Such transients would require the use of 3D-neutron kinetics model to describe properly the strong space-time effect on the power distribution in the reactor core

  6. Analysis of water hammer phenomena in RBMK-1500 reactor main circulation circuit

    International Nuclear Information System (INIS)

    Kaliatka, A.; Uspuras, E.; Vaisnoras, M.

    2006-01-01

    Water hammer can occur in any thermal-hydraulic systems. Water hammer can reach pressure levels far exceeding the pressure range of a pipe given by the manufacturer, and it can lead to the failure of the pipeline integrity. In the past three decades, since a large number of water hammer events occurred in the light-water- reactor power plants, a number of comprehensive studies on the phenomena associated with water hammer events have been performed. There are three basic types of severe water hammer occurring at power plants that can result in significant plant damage: rapid valve operation events; void-induced water hammer; condensation-induced water hammer. Correct prediction of water hammer transients, is therefore of paramount importance for the safe operation of the plant. Therefore verifying of computer codes capability to simulate water hammer type transients is very important issue at performing of safety analyses for nuclear power plants. Verification of RELAP5/MOD3.3 code capability to simulate water hammer type transients employing the experimental investigations is presented. Experience gained from benchmarking analyses has been used at development of the detail RELAP5 code RBMK-1500 model for simulation of water hammer effects in reactor main circulation circuit. Analysis of reactor cooling system shows, that water hammers can occur in main circulation circuit of RBMK-1500 reactor in cases of: (1) Guillotine break of the inlet piping upstream of the Group Distribution Header and (2) Guillotine break of the pressure piping upstream the Main Circulation Pump check valve. Analysis of above mentioned accident scenarios is presented in this paper. First scenario of the accident potentially is more dangerous, because the pressure pulses influence not only the reactor cooling circuit, but also the piping of safety related system (Emergency Core Cooling System pipeline) connected to affected Group Distribution Header. The performed analysis using RELAP5 code

  7. Forcing mechanisms of the Bay of Bengal circulation

    Digital Repository Service at National Institute of Oceanography (India)

    Vinayachandran, P.N.; Shetye, S.R.; Sengupta, D.; Gadgil, S.

    A state-of-the-art ocean general circulation model, set up for the North Indian Ocean and driven by climatological wind stress simulates most of the observed features of the near-surface circulation of the Bay of Bengal. The prominent features...

  8. Analysis of Electromagnetic Attractive Force : Examination by Magnetic Circuit, Finite Element Method and Experiment

    OpenAIRE

    薮野, 浩司; 大和田, 竜太郎; 青島, 伸治; Hiroshi, YABUNO; Ryotaro, OOWADA; Nobuharu, AOSHIMA; 筑波大学; 筑波大学院; 筑波大学

    1998-01-01

    This paper presents the limitation of the magnetic circuit method. The force between magnetic bodies can be approximated accurately by the magnetic circuit method. Therefore this method has been used widely for the estimation of magnetic force. However this method is limited by the magnetic leakage and can be not used in the case when the gap between the magnetic bodies is wide. It is very important to clarify the limitation of the magnetic circuit method. In this research, the force of an el...

  9. Measurement of liquid level in a natural circulation circuit using an ultrasonic technique

    International Nuclear Information System (INIS)

    Barbosa, Amanda Cardozo; Su, Jian

    2017-01-01

    The measurement by an ultrasonic technique of the water level in the expansion tank of the Natural Circulation Circuit (NCC) of the Experimental Thermo-Hydraulic Laboratory of the Institute of Nuclear Engineering is presented. In the single-phase NCC operation the water level in the expansion tank is stable. However, during the two-phase operation, oscillations occur in the water level due to temperature and vacuum fraction variations. Thus, the development of a technique that allows the measurement of these oscillations, will allow an estimation of the variation of the vacuum fraction of the circuit over time. The experimental set - up was performed on a test bench, using an ultrasonic transducer. The ultrasonic technique used is pulse-echo, in which the same transducer is the transmitter and receiver of the signal. The transducer-shoe assembly is part of an ultrasonic system consisting of an ultrasonic signal generating plate, transducers and a computer (PC) with a program in LabView to control the system. The program is able to calculate the transit time that the ultrasonic signals take to cross the tank base wall, the layer (level) of liquid and return to the transducer. Knowing the speed of the ultrasound in the wall and in the liquid it is possible to calculate the thickness of the wall and the height of the liquid. Measurements were made by filling the tank with a known volume of water and under varying temperature conditions, from room temperature to 90 deg C. The liquid heights are determined and the volume of water calculated by measuring the temperature with a digital thermometer. The volumes measured were highly accurate when compared to the known volumes

  10. Forces and stresses in cryoturbogenerator rotor in presence of short circuit

    International Nuclear Information System (INIS)

    Kovarskii, M.E.; Rubinraut, A.M.; Tsyrlin, A.L.

    1981-01-01

    A method is presented for determining the electrodynamic forces, mechanical stresses, and strains in the shells of a cryogenic-turbogenerator cryostat in the presence of an abrupt short circuit. The physical pattern of occurrence of forces in a cryostat shell is considered for capacitive, inductive, and active armature-current cases. It is shown that in addition to the radial component, there is a tangential component of the electrodynamic forces, with the interaction of the two components governing the strength in the presence of short circuits. Results are reported for mechanical-strength calculations, based on the proposed method, for a 200 kw cryogenic turbogenerator

  11. Magnetic Circuit Model of PM Motor-Generator to Predict Radial Forces

    Science.gov (United States)

    McLallin, Kerry (Technical Monitor); Kascak, Peter E.; Dever, Timothy P.; Jansen, Ralph H.

    2004-01-01

    A magnetic circuit model is developed for a PM motor for flywheel applications. A sample motor is designed and modeled. Motor configuration and selection of materials is discussed, and the choice of winding configuration is described. A magnetic circuit model is described, which includes the stator back iron, rotor yoke, permanent magnets, air gaps and the stator teeth. Iterative solution of this model yields flux linkages, back EMF, torque, power, and radial force at the rotor caused by eccentricity. Calculated radial forces are then used to determine motor negative stiffness.

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

    Science.gov (United States)

    Hagos, S.; Zhang, C.

    2008-12-01

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

  13. Magnetic force microscopy method and apparatus to detect and image currents in integrated circuits

    Science.gov (United States)

    Campbell, Ann. N.; Anderson, Richard E.; Cole, Jr., Edward I.

    1995-01-01

    A magnetic force microscopy method and improved magnetic tip for detecting and quantifying internal magnetic fields resulting from current of integrated circuits. Detection of the current is used for failure analysis, design verification, and model validation. The interaction of the current on the integrated chip with a magnetic field can be detected using a cantilevered magnetic tip. Enhanced sensitivity for both ac and dc current and voltage detection is achieved with voltage by an ac coupling or a heterodyne technique. The techniques can be used to extract information from analog circuits.

  14. Analytical study on thermal-hydraulic behavior of transient from forced circulation to natural circulation in JRR-3

    International Nuclear Information System (INIS)

    Hirano, Masashi; Sudo, Yukio

    1986-01-01

    Transient thermal-hydraulic behaviors of the JRR-3 which is an open-pool type research reactor has been analyzed with the THYDE-P1 code. The focal point is the thermal-hydraulic behaviors related to the core flow reversal during the transition from forced circulation downflow to natural circulation upflow. In the case of a loss-of-coolant accident (LOCA), for example, the core flow reversal is expected to occur just after the water pool isolation from the primary cooling loop with a leak. The core flow reversal should cause a sudden increase in fuel temperature and a steep decrease in the departure-from-nucleate-boiling ratio (DNBR) and the phenomenon is, therefore, very important especially for safety design and evaluation of research reactors. Major purposes of the present work are to clarify physical phenomena during the transient and to identify important parameters affecting the peak fuel temperature and the minimum DNBR. The results calculated with THYDE-P1 assuming the sequences of events of the loss-of-offsite power and LOCA help us to understand the phenomena both qualitatively and quantitatively, with respect to the safety design and evaluation. (author)

  15. Functional end-arterial circulation of the choroid assessed by using fat embolism and electric circuit simulation.

    Science.gov (United States)

    Lee, Ji Eun; Ahn, Ki Su; Park, Keun Heung; Pak, Kang Yeun; Kim, Hak Jin; Byon, Ik Soo; Park, Sung Who

    2017-05-30

    The discrepancy in the choroidal circulation between anatomy and function has remained unsolved for several decades. Postmortem cast studies revealed extensive anastomotic channels, but angiographic studies indicated end-arterial circulation. We carried out experimental fat embolism in cats and electric circuit simulation. Perfusion defects were observed in two categories. In the scatter perfusion defects suggesting an embolism at the terminal arterioles, fluorescein dye filled the non-perfused lobule slowly from the adjacent perfused lobule. In the segmental perfusion defects suggesting occlusion of the posterior ciliary arteries, the hypofluorescent segment became perfused by spontaneous resolution of the embolism without subsequent smaller infarction. The angiographic findings could be simulated with an electric circuit. Although electric currents flowed to the disconnected lobule, the level was very low compared with that of the connected ones. The choroid appeared to be composed of multiple sectors with no anastomosis to other sectors, but to have its own anastomotic arterioles in each sector. Blood flows through the continuous choriocapillaris bed in an end-arterial nature functionally to follow a pressure gradient due to the drainage through the collector venule.

  16. Study of turbulent natural-circulation flow and low-Prandtl-number forced-convection flow

    International Nuclear Information System (INIS)

    Chung, K.S.; Thompson, D.H.

    1980-01-01

    Calculational methods and results are discussed for the coupled energy and momentum equations of turbulent natural circulation flow and low Prandtl number forced convection flow. The objective of this paper is to develop a calculational method for the study of the thermal-hydraulic behavior of coolant flowing in a liquid metal fast breeder reactor channel under natural circulation conditions. The two-equation turbulence model is used to evaluate the turbulent momentum transport property. Because the analogy between momentum transfer and heat transfer does not generally hold for low Prandtl number fluid and natural circulation flow conditions, the turbulent thermal conductivity is calculated independently using equations similar to the two-equation turbulence model. The numerical technique used in the calculation is the finite element method

  17. Reduced scaling of thermal-hydraulic circuits for studies of PWR reactors natural circulation

    International Nuclear Information System (INIS)

    Botelho, D.A.

    1993-01-01

    The Ishii et al. hydrodynamic similarity criteria for natural circulation were used for scaling reduced models of prototype passive residual heat removal system of a 600 M We PWR. The physical scales of the thermohydraulic parameters obtained presented a reasonable agreement when compared with simplified analytic models of the systems. (author)

  18. Operational Augmentation of Forced Circulation Type Solar Dryer System Using CFD Analysis

    OpenAIRE

    Atul Patel; Gaurav Patel

    2014-01-01

    Solar drying is basically heat and mass transfer process in which the liquid water from the surface and the vapour removed by draft. The efficiency of a solar drying system is affected by the properties of drying materials.e.g. size, shape and geometry as well as ambient conditions. In this research article, the authors have done the CFD analysis of a Forced Circulation type Solar Dryer used conventionally for dehydrating vegetables and fruits. Using CFD analysis, the limiting...

  19. Response of Ocean Circulation to Different Wind Forcing in Puerto Rico and US Virgin Islands

    Science.gov (United States)

    Solano, Miguel; Garcia, Edgardo; Leonardi, Stafano; Canals, Miguel; Capella, Jorge

    2013-11-01

    The response of the ocean circulation to various wind forcing products has been studied using the Regional Ocean Modeling System. The computational domain includes the main islands of Puerto Rico, Saint John and Saint Thomas, located on the continental shelf dividing the Caribbean Sea and the Atlantic Ocean. Data for wind forcing is provided by an anemometer located in a moored buoy, the Coupled Ocean-Atmosphere Mesoscale Prediction System (COAMPS) model and the National Digital Forecast Database (NDFD). Hindcast simulations have been validated using hydrographic data at different locations in the area of study. Three cases are compared to quantify the impact of high resolution wind forcing on the ocean circulation and the vertical structure of salinity, temperature and velocity. In the first case a constant wind velocity field is used to force the model as measured by an anemometer on top of a buoy. In the second case, a forcing field provided by the Navy's COAMPS model is used and in the third case, winds are taken from NDFD in collaboration with the National Centers for Environmental Prediction. Validated results of ocean currents against data from Acoustic Doppler Current Profilers at different locations show better agreement using high resolution wind data as expected. Thanks to CariCOOS and NOAA.

  20. Climate forcings and climate sensitivities diagnosed from atmospheric global circulation models

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Bruce T. [Boston University, Department of Geography and Environment, Boston, MA (United States); Knight, Jeff R.; Ringer, Mark A. [Met Office Hadley Centre, Exeter (United Kingdom); Deser, Clara; Phillips, Adam S. [National Center for Atmospheric Research, Boulder, CO (United States); Yoon, Jin-Ho [University of Maryland, Cooperative Institute for Climate and Satellites, Earth System Science Interdisciplinary Center, College Park, MD (United States); Cherchi, Annalisa [Centro Euro-Mediterraneo per i Cambiamenti Climatici, and Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy)

    2010-12-15

    Understanding the historical and future response of the global climate system to anthropogenic emissions of radiatively active atmospheric constituents has become a timely and compelling concern. At present, however, there are uncertainties in: the total radiative forcing associated with changes in the chemical composition of the atmosphere; the effective forcing applied to the climate system resulting from a (temporary) reduction via ocean-heat uptake; and the strength of the climate feedbacks that subsequently modify this forcing. Here a set of analyses derived from atmospheric general circulation model simulations are used to estimate the effective and total radiative forcing of the observed climate system due to anthropogenic emissions over the last 50 years of the twentieth century. They are also used to estimate the sensitivity of the observed climate system to these emissions, as well as the expected change in global surface temperatures once the climate system returns to radiative equilibrium. Results indicate that estimates of the effective radiative forcing and total radiative forcing associated with historical anthropogenic emissions differ across models. In addition estimates of the historical sensitivity of the climate to these emissions differ across models. However, results suggest that the variations in climate sensitivity and total climate forcing are not independent, and that the two vary inversely with respect to one another. As such, expected equilibrium temperature changes, which are given by the product of the total radiative forcing and the climate sensitivity, are relatively constant between models, particularly in comparison to results in which the total radiative forcing is assumed constant. Implications of these results for projected future climate forcings and subsequent responses are also discussed. (orig.)

  1. Effects of wave-induced forcing on a circulation model of the North Sea

    Science.gov (United States)

    Staneva, Joanna; Alari, Victor; Breivik, Øyvind; Bidlot, Jean-Raymond; Mogensen, Kristian

    2017-04-01

    The effect of wind waves on water level and currents during two storms in the North Sea is investigated using a high-resolution NEMO model forced with fluxes and fields from a high-resolution wave model. The additional terms accounting for wave-current interaction that are considered in this study are the Stokes-Coriolis force and the sea-state dependent energy and momentum fluxes. The individual and collective role of these processes is quantified and the results are compared with a control run without wave effects as well as against current and water level measurements from coastal stations. We find a better agreement with observations when the circulation model is forced by sea-state dependent fluxes, especially in extreme events. The two extreme events, the storm Christian (25-27 October 2013), and about a month later, the storm Xaver (5-7 December 2013), induce different wave and surge conditions over the North Sea. Including the wave effects in the circulation model for the storm Xaver raises the modelled surge by more than 40 cm compared with the control run in the German Bight area. For the storm Christian, a difference of 20-30 cm in the surge level between the wave-forced and the stand-alone ocean model is found over the whole southern part of the North Sea. Moreover, the modelled vertical velocity profile fits the observations very well when the wave forcing is accounted for. The contribution of wave-induced forcing has been quantified indicating that this represents an important mechanism for improving water level and current predictions.

  2. Response of the meridional overturning circulation to variable buoyancy forcing in a double hemisphere basin

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, Marc A. [National Oceanography Centre, University of Southampton, School of Ocean and Earth Science, Southampton (United Kingdom); Collecte Localisation Satellite, Ramonville Saint Agne (France); Hirschi, J.J.M. [National Oceanography Centre, University of Southampton, School of Ocean and Earth Science, Southampton (United Kingdom); Marotzke, J. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

    2010-04-15

    We consider how a highly idealized double-hemisphere basin responds to a zonally constant restoring surface temperature profile that oscillates in time, with periods ranging from 0.5 to 32,000 years. In both hemispheres, the forcing is similar but can be either in phase or out of phase. The set-up is such that the Northern Hemisphere always produces the densest waters. The model's meridional overturning circulation (MOC) exhibits a strong response in both hemispheres on decadal to multi-millennial timescales. The amplitude of the oscillations reaches up to 140% of the steady-state maximum MOC and exhibits resonance-like behaviour, with a maximum at centennial to millennial forcing periods. When the forcing is in phase between the Northern and Southern Hemispheres, there is a marked decrease in the amplitude of the MOC response as the forcing period is increased beyond the resonance period. In this case the resonance-like behaviour is identical to the one we found earlier in a single-hemisphere model and occurs for the same reasons. When the forcing is out of phase between the Northern and Southern Hemispheres, the amplitude of the MOC response is substantially greater for long forcing periods (millennial and longer), particularly in the Southern Hemisphere. This increased MOC amplitude occurs because for an out of phase forcing, either the northern or the southern deep water source is always active, leading to generally colder bottom waters and thus greater stratification in the opposite hemisphere. This increased stratification in turn stabilises the water column and thus reduces the strength of the weaker overturning cell. The interaction of the two hemispheres leads to response timescales of the deep ocean at half the forcing period. Our results suggest a possible explanation for the half-precessional time scale observed in the deep Atlantic Ocean palaeo-temperature record. (orig.)

  3. Bubbling route to strange nonchaotic attractor in a nonlinear series LCR circuit with a nonsinusoidal force.

    Science.gov (United States)

    Senthilkumar, D V; Srinivasan, K; Thamilmaran, K; Lakshmanan, M

    2008-12-01

    We identify an unconventional route to the creation of a strange nonchaotic attractor (SNA) in a quasiperiodically forced electronic circuit with a nonsinusoidal (square wave) force as one of the quasiperiodic forces through numerical and experimental studies. We find that bubbles appear in the strands of the quasiperiodic attractor due to the instability induced by the additional square-wave-type force. The bubbles then enlarge and get increasingly wrinkled as a function of the control parameter. Finally, the bubbles get extremely wrinkled (while the remaining parts of the strands of the torus remain largely unaffected) resulting in the creation of the SNA; we term this the bubbling route to the SNA. We characterize and confirm this creation from both experimental and numerical data using maximal Lyapunov exponents and their variance, Poincaré maps, Fourier amplitude spectra, and spectral distribution functions. We also strongly confirm the creation of a SNA via the bubbling route by the distribution of the finite-time Lyapunov exponents.

  4. The Effect of Wind Forcing on Modeling Coastal Circulation at a Marine Renewable Test Site

    Directory of Open Access Journals (Sweden)

    Lei Ren

    2017-12-01

    Full Text Available The hydrodynamic circulation in estuaries is primarily driven by tides, river inflows and surface winds. While tidal and river data can be quite easily obtained for input to hydrodynamic models, sourcing accurate surface wind data is problematic. Inaccurate wind data can lead to inaccuracies in the surface currents computed by three-dimensional hydrodynamic models. In this research, a high-resolution wind model was coupled with a three-dimensional hydrodynamic model of Galway Bay, a semi-enclosed estuary on the west coast of Ireland, to investigate the effect of wind forcing on model accuracy. Two wind-forcing conditions were investigated: (1 using wind data measured onshore on the NUI Galway campus (NUIG and (2 using offshore wind data provided by a high resolution wind model (HR. A scenario with no wind forcing (NW was also assessed. The onshore wind data varied with time but the speed and direction were applied across the full model domain. The modeled offshore wind fields varied with both time and space. The effect of wind forcing on modeled hydrodynamics was assessed via comparison of modeled surface currents with surface current measurements obtained from a High-Frequency (HF radar Coastal Ocean Dynamics Applications Radar (CODAR observation system. Results indicated that winds were most significant in simulating the north-south surface velocity component. The model using high resolution temporally- and spatially-varying wind data achieved better agreement with the CODAR surface currents than the model using the onshore wind measurements and the model without any wind forcing.

  5. Interannual Variation of Surface Circulation in the Japan/East Sea due to External Forcings and Intrinsic Variability

    Science.gov (United States)

    Choi, Byoung-Ju; Cho, Seong Hun; Jung, Hee Seok; Lee, Sang-Ho; Byun, Do-Seong; Kwon, Kyungman

    2018-03-01

    The interannual variation of surface ocean currents can be as large as seasonal variation in the Japan/East Sea (JES). To identify the major factors that cause such interannual variability of surface ocean circulation in the JES, surface circulation was simulated from 1998 to 2009 using a three-dimensional model. Contributions of atmospheric forcing (ATM), open boundary data (OBC), and intrinsic variability (ITV) of the surface flow in the JES on the interannual variability of surface ocean circulation were separately examined using numerical simulations. Variability in surface circulation was quantified in terms of variance in sea surface height, 100-m depth water temperature, and surface currents. ITV was found to be the dominant factor that induced interannual variabilities of surface circulation, the main path of the East Korea Warm Current (EKWC), and surface kinetic energy on a time scale of 2-4 years. OBC and ATM were secondary factors contributing to the interannual variation of surface circulation. Interannual variation of ATM changed the separation latitude of EKWC and increased the variability of surface circulation in the Ulleung Basin. Interannual variation of OBC enhanced low-frequency changes in surface circulation and eddies in the Yamato Basin. It also modulated basin-wide uniform oscillations of sea level. This study suggests that precise estimation of initial conditions using data assimilation is essential for long-term prediction of surface circulation in the JES.

  6. Impact of remote oceanic forcing on Gulf of Alaska sea levels and mesoscale circulation

    Science.gov (United States)

    Melsom, Arne; Metzger, E. Joseph; Hurlburt, Harley E.

    2003-11-01

    We examine the relative importance of regional wind forcing and teleconnections by an oceanic pathway for impact on interannual ocean circulation variability in the Gulf of Alaska. Any additional factors that contribute to this variability, such as freshwater forcing from river runoff, are disregarded. The study is based on results from numerical simulations, sea level data from tide gauge stations, and sea surface height anomalies from satellite altimeter data. At the heart of this investigation is a comparison of ocean simulations that include and exclude interannual oceanic teleconnections of an equatorial origin. Using lagged correlations, the model results imply that 70-90% of the interannual coastal sea level variance in the Gulf of Alaska can be related to interannual sea levels at La Libertad, Equador. These values are higher than the corresponding range from sea level data, which is 25-55%. When oceanic teleconnections from the equatorial Pacific are excluded in the model, the explained variance becomes about 20% or less. During poleward propagation the coastally trapped sea level signal in the model is less attenuated than the observed signal. In the Gulf of Alaska we find well-defined sea level peaks in the aftermath of El Niño events. The interannual intensity of eddies in the Gulf of Alaska also peaks after El Niño events; however, these maxima are less clear after weak and moderate El Niño events. The interannual variations in eddy activity intensity are predominantly governed by the regional atmospheric forcing.

  7. Measurement of circulation around wing-tip vortices and estimation of lift forces using stereo PIV

    Science.gov (United States)

    Asano, Shinichiro; Sato, Haru; Sakakibara, Jun

    2017-11-01

    Applying the flapping flight to the development of an aircraft as Mars space probe and a small aircraft called MAV (Micro Air Vehicle) is considered. This is because Reynolds number assumed as the condition of these aircrafts is low and similar to of insects and small birds flapping on the earth. However, it is difficult to measure the flow around the airfoil in flapping flight directly because of its three-dimensional and unsteady characteristics. Hence, there is an attempt to estimate the flow field and aerodynamics by measuring the wake of the airfoil using PIV, for example the lift estimation method based on a wing-tip vortex. In this study, at the angle of attack including the angle after stall, we measured the wing-tip vortex of a NACA 0015 cross-sectional and rectangular planform airfoil using stereo PIV. The circulation of the wing-tip vortex was calculated from the obtained velocity field, and the lift force was estimated based on Kutta-Joukowski theorem. Then, the validity of this estimation method was examined by comparing the estimated lift force and the force balance data at various angles of attack. The experiment results are going to be presented in the conference.

  8. An Open Source Low-Cost Wireless Control System for a Forced Circulation Solar Plant.

    Science.gov (United States)

    Salamone, Francesco; Belussi, Lorenzo; Danza, Ludovico; Ghellere, Matteo; Meroni, Italo

    2015-11-05

    The article describes the design phase, development and practical application of a low-cost control system for a forced circulation solar plant in an outdoor test cell located near Milan. Such a system provides for the use of an electric pump for the circulation of heat transfer fluid connecting the solar thermal panel to the storage tank. The running plant temperatures are the fundamental parameter to evaluate the system performance such as proper operation, and the control and management system has to consider these parameters. A solar energy-powered wireless-based smart object was developed, able to monitor the running temperatures of a solar thermal system and aimed at moving beyond standard monitoring approaches to achieve a low-cost and customizable device, even in terms of installation in different environmental conditions. To this end, two types of communications were used: the first is a low-cost communication based on the ZigBee protocol used for control purposes, so that it can be customized according to specific needs, while the second is based on a Bluetooth protocol used for data display.

  9. An Open Source Low-Cost Wireless Control System for a Forced Circulation Solar Plant

    Directory of Open Access Journals (Sweden)

    Francesco Salamone

    2015-11-01

    Full Text Available The article describes the design phase, development and practical application of a low-cost control system for a forced circulation solar plant in an outdoor test cell located near Milan. Such a system provides for the use of an electric pump for the circulation of heat transfer fluid connecting the solar thermal panel to the storage tank. The running plant temperatures are the fundamental parameter to evaluate the system performance such as proper operation, and the control and management system has to consider these parameters. A solar energy-powered wireless-based smart object was developed, able to monitor the running temperatures of a solar thermal system and aimed at moving beyond standard monitoring approaches to achieve a low-cost and customizable device, even in terms of installation in different environmental conditions. To this end, two types of communications were used: the first is a low-cost communication based on the ZigBee protocol used for control purposes, so that it can be customized according to specific needs, while the second is based on a Bluetooth protocol used for data display.

  10. Analysis of a BWR direct cycle forced circulation power plants operation

    International Nuclear Information System (INIS)

    Andrade, G.G. de.

    1973-01-01

    First, it is established a general view over the operational problems of the BWR direct cycle forced circulation power plants, and then it is analysed the possibility of the utilization of the energy purged from the turbine as an additional energy for the electrical generation. To simulate the BWR power plant and to obtain the solution of the mathematical model it was developed a computer code named ATOR which shows the feasibility of the proposed method. In this way it is shown the possibility to get a better maneuvering allowance for the BWR power plant whenever it is permitted a convenient use of the vapor extracted from the turbine for the feedwater pre-heaters of the reactor. (author)

  11. Relative contributions of external forcing factors to circulation and hydrographic properties in a micro-tidal bay

    Science.gov (United States)

    Yoon, Seokjin; Kasai, Akihide

    2017-11-01

    The dominant external forcing factors influencing estuarine circulation differ among coastal environments. A three-dimensional regional circulation model was developed to estimate external influence indices and relative contributions of external forcing factors such as external oceanic forcing, surface heat flux, wind stress, and river discharge to circulation and hydrographic properties in Tango Bay, Japan. Model results show that in Tango Bay, where the Tsushima Warm Current passes offshore of the bay, under conditions of strong seasonal winds and river discharge, the water temperature and salinity are strongly influenced by surface heat flux and river discharge in the surface layer, respectively, while in the middle and bottom layers both are mainly controlled by open boundary conditions. The estuarine circulation is comparably influenced by all external forcing factors, the strong current, surface heat flux, wind stress, and river discharge. However, the influence degree of each forcing factor varies with temporal variations in external forcing factors as: the influence of open boundary conditions is higher in spring and early summer when the stronger current passes offshore of the bay, that of surface heat flux reflects the absolute value of surface heat flux, that of wind stress is higher in late fall and winter due to strong seasonal winds, and that of river discharge is higher in early spring due to snow-melting and summer and early fall due to flood events.

  12. Atmospheric circulation response to anthropogenic forcings: from annular modes to storm tracks

    International Nuclear Information System (INIS)

    Oudar, Thomas

    2016-01-01

    Climate variability in mid and high latitudes is very complex due to numerous physical mechanisms implied. This climate variability can be decomposed into 2 components: the internal variability associated with internal processes and the forced variability linked to the external forcings which can be natural (volcanism, natural aerosols) or anthropogenic (greenhouse gases, anthropogenic aerosols). These external forcings play a crucial role on the climate and its variability. The challenge in the climate research is to understand their effects on the climate and their roles relatively with the internal variability. The objective of this thesis is a better understanding of the respective roles of internal variability and forced variability on the past and future atmospheric circulation in both hemispheres characterized by the annular mode and the synoptic activity associated using atmospheric reanalysis and experiments performed with the coupled climate model CNRM-CM5. First, we focus on the annular mode changes in both hemispheres, named the NAM (Northern Annular Mode) and the SAM (Southern Annular Mode). We show that the observed positive trend of the SAM in the 1960's in austral summer is well reproduced by the climate model. However, contrarily to other studies which suggest that this positive trend can be explained by only stratospheric ozone depletion, it is reproduced in the CNRM-CM5 model when the ozone depletion and greenhouse gases (GHG) increase are both prescribed. Then, we investigate the changes in the Northern Hemisphere atmospheric circulation. These are more complex than in the Southern Hemisphere. Indeed, the increase of GHG in the atmosphere causes a general global warming maximum in the tropical high troposphere and over the pole at the surface which is mainly explained by Arctic sea ice loss. So the understanding of the changes is very complex due to several physical processes and retroactions. Thus, we have conducted a protocol with the coupled

  13. Forced synchronization of large-scale circulation to increase predictability of surface states

    Science.gov (United States)

    Shen, Mao-Lin; Keenlyside, Noel; Selten, Frank; Wiegerinck, Wim; Duane, Gregory

    2016-04-01

    Numerical models are key tools in the projection of the future climate change. The lack of perfect initial condition and perfect knowledge of the laws of physics, as well as inherent chaotic behavior limit predictions. Conceptually, the atmospheric variables can be decomposed into a predictable component (signal) and an unpredictable component (noise). In ensemble prediction the anomaly of ensemble mean is regarded as the signal and the ensemble spread the noise. Naturally the prediction skill will be higher if the signal-to-noise ratio (SNR) is larger in the initial conditions. We run two ensemble experiments in order to explore a way to reduce the SNR of surface winds and temperature. One ensemble experiment is AGCM with prescribing sea surface temperature (SST); the other is AGCM with both prescribing SST and nudging the high-level temperature and winds to ERA-Interim. Each ensemble has 30 members. Larger SNR is expected and found over the tropical ocean in the first experiment because the tropical circulation is associated with the convection and the associated surface wind convergence as these are to a large extent driven by the SST. However, small SNR is found over high latitude ocean and land surface due to the chaotic and non-synchronized atmosphere states. In the second experiment the higher level temperature and winds are forced to be synchronized (nudged to reanalysis) and hence a larger SNR of surface winds and temperature is expected. Furthermore, different nudging coefficients are also tested in order to understand the limitation of both synchronization of large-scale circulation and the surface states. These experiments will be useful for the developing strategies to synchronize the 3-D states of atmospheric models that can be later used to build a super model.

  14. Dynamical and statistical phenomena of circulation and heat transfer in periodically forced rotating turbulent Rayleigh-Bénard convection

    NARCIS (Netherlands)

    Sterl, S.H.; Li, H.M.; Zhong, J.Q.

    2016-01-01

    In this paper, we present results from an experimental study into turbulent Rayleigh-Bénard convection forced externally by periodically modulated unidirectional rotation rates. We find that the azimuthal rotation velocity θ(t) and thermal amplitude δ(t) of the large-scale circulation (LSC) are

  15. Experimental investigation on flow instability of forced circulation in a vertical mini-rectangular channel

    International Nuclear Information System (INIS)

    Yu Zhiting; Tan Sichao; Yuan Hongsheng; Zhuang Nailiang; Chen Hanying

    2015-01-01

    An experimental study was conducted to investigate the flow instability in a vertical mini-rectangular channel with distilled water as the working fluid. The rotational speed of the primary pump is gradually reduced to lower the inlet flow rate until the flow becomes unstable, while maintaining all other thermal parameters unchanged. Three types of instability, characterized by large amplitude oscillation, small amplitude oscillation and flow excursion, were identified from the experimental data. A stability map for the vertical mini-rectangular channel under forced circulation was established based on the Subcooling number and Phase Change number. The oscillation periods were correlated with the fluid transit time and the boiling delay time. A flow pattern map for vertical upward flow in a mini-rectangular channel was applied to confirm the flow patterns during the oscillation. The mechanisms of the three types of instability were obtained by considering several types of flow instabilities and comparing them with the oscillations observed in this work. (author)

  16. Experimental study of the transition from forced to natural circulation in EBR-II at low power and flow

    International Nuclear Information System (INIS)

    Gillette, J.L.; Singer, R.M.; Tokar, J.V.; Sullivan, J.E.

    1979-01-01

    A series of tests have been conducted in EBR-II which studied the dynamics of the transition from forced to natural circulation flow in a liquid-metal-cooled fast breeder reactor (LMFBR). Each test was initiated by abruptly tripping an electromagnetic pump which supplies 5 to 6% of the normal full operational primary flow rate. The ensuing flow coast-down reached a minimum value after which the flow increased as natural circulation was established. The effects of secondary system flow through the intermediate heat exchanger and reactor decay power level on the minimum in-core flow rates and maximum in-core temperatures were examined

  17. Exposure to Forced Swim Stress Alters Local Circuit Activity and Plasticity in the Dentate Gyrus of the Hippocampus

    Directory of Open Access Journals (Sweden)

    Mouna Maroun

    2008-02-01

    Full Text Available Studies have shown that, depending on its severity and context, stress can affect neural plasticity. Most related studies focused on synaptic plasticity and long-term potentiation (LTP of principle cells. However, evidence suggests that following high-frequency stimulation, which induces LTP in principal cells, modifications also take place at the level of complex interactions with interneurons within the dentate gyrus, that is, at the local circuit level. So far, the possible effects of stress on local circuit activity and plasticity were not studied. Therefore, we set out to examine the possible alterations in local circuit activity and plasticity following exposure to stress. Local circuit activity and plasticity were measured by using frequency dependant inhibition (FDI and commissural modulation protocols following exposure to a 15 minute-forced swim trial. Exposure to stress did not alter FDI. The application of theta-burst stimulation (TBS reduced FDI in both control and stressed rats, but this type of plasticity was greater in stressed rats. Commissural-induced inhibition was significantly higher in stressed rats both before and after applying theta-burst stimulation. These findings indicate that the exposure to acute stress affects aspects of local circuit activity and plasticity in the dentate gyrus. It is possible that these alterations underlie some of the behavioral consequences of the stress experience.

  18. Exposure to Forced Swim Stress Alters Local Circuit Activity and Plasticity in the Dentate Gyrus of the Hippocampus

    Science.gov (United States)

    Yarom, Orli; Maroun, Mouna; Richter-Levin, Gal

    2008-01-01

    Studies have shown that, depending on its severity and context, stress can affect neural plasticity. Most related studies focused on synaptic plasticity and long-term potentiation (LTP) of principle cells. However, evidence suggests that following high-frequency stimulation, which induces LTP in principal cells, modifications also take place at the level of complex interactions with interneurons within the dentate gyrus, that is, at the local circuit level. So far, the possible effects of stress on local circuit activity and plasticity were not studied. Therefore, we set out to examine the possible alterations in local circuit activity and plasticity following exposure to stress. Local circuit activity and plasticity were measured by using frequency dependant inhibition (FDI) and commissural modulation protocols following exposure to a 15 minute-forced swim trial. Exposure to stress did not alter FDI. The application of theta-burst stimulation (TBS) reduced FDI in both control and stressed rats, but this type of plasticity was greater in stressed rats. Commissural-induced inhibition was significantly higher in stressed rats both before and after applying theta-burst stimulation. These findings indicate that the exposure to acute stress affects aspects of local circuit activity and plasticity in the dentate gyrus. It is possible that these alterations underlie some of the behavioral consequences of the stress experience. PMID:18301720

  19. Atmospheric radiation measurement: A program for improving radiative forcing and feedback in general circulation models

    International Nuclear Information System (INIS)

    Patrinos, A.A.; Renne, D.S.; Stokes, G.M.; Ellingson, R.G.

    1991-01-01

    The Atmospheric Radiation Measurement (ARM) Program is a key element of the Department of Energy's (DOE's) global change research strategy. ARM represents a long-term commitment to conduct comprehensive studies of the spectral atmospheric radiative energy balance profile for a wide range of cloud conditions and surface types, and to develop the knowledge necessary to improve parameterizations of radiative processes under various cloud regimes for use in general circulation models (GCMs) and related models. The importance of the ARM program is a apparent from the results of model assessments of the impact on global climate change. Recent studies suggest that radiatively active trace gas emissions caused by human activity can lead to a global warming of 1.5 to 4.5 degrees Celsius and to important changes in water availability during the next century (Cess, et al. 1989). These broad-scale changes can be even more significant at regional levels, where large shifts in temperature and precipitation patterns are shown to occur. However, these analyses also indicate that considerable uncertainty exists in these estimates, with the manner in which cloud radiative processes are parameterized among the most significant uncertainty. Thus, although the findings have significant policy implications in assessment of global and regional climate change, their uncertainties greatly influence the policy debate. ARM's highly focused observational and analytical research is intended to accelerate improvements and reduce key uncertainties associated with the way in which GCMs treat cloud cover and cloud characteristics and the resulting radiative forcing. This paper summarizes the scientific context for ARM, ARM's experimental approach, and recent activities within the ARM program

  20. Remarkable separability of the circulation response to Arctic sea ice loss and greenhouse gas forcing

    Science.gov (United States)

    McCusker, K. E.; Kushner, P. J.; Fyfe, J. C.; Sigmond, M.; Kharin, V. V.; Bitz, C. M.

    2017-12-01

    Arctic sea ice loss has an important effect on local climate through increases in ocean to atmosphere heat flux and associated feedbacks, and may influence midlatitude climate by changing large-scale circulation that can enhance or counter changes that are due to greenhouse gases. The extent to which climate change in a warming world can be understood as greenhouse gas-induced changes that are modulated by Arctic sea ice loss depends on how additive the responses to the separate influences are. Here we use a novel sea ice nudging methodology in the Canadian Earth System Model, which has a fully coupled ocean, to isolate the effects of Arctic sea ice loss and doubled atmospheric carbon dioxide (CO2) to determine their additivity and sensitivity to mean state. We find that the separate effects of Arctic sea ice loss and doubled CO2 are remarkably additive and relatively insensitive to mean climate state. This separability is evident in several thermodynamic and dynamic fields throughout most of the year, from hemispheric to synoptic scales. The extent to which the regional response to sea ice loss sometimes agrees with and sometimes cancels the response to CO2 is quantified. In this model, Arctic sea ice loss enhances the CO2-induced surface air temperature changes nearly everywhere and zonal wind changes over the Pacific sector, whereas sea ice loss counters CO2-induced sea level pressure changes nearly everywhere over land and zonal wind changes over the Atlantic sector. This separability of the response to Arctic sea ice loss from the response to CO2 doubling gives credence to the body of work in which Arctic sea ice loss is isolated from the forcing that modified it, and might provide a means to better interpret the diverse array of modeling and observational studies of Arctic change and influence.

  1. A system for the discharge of gas bubbles from the coolant flow of a nuclear reactor cooled by forced circulation

    International Nuclear Information System (INIS)

    Markfort, D.; Kaiser, A.; Dohmen, A.

    1975-01-01

    In a reactor cooled by forced circulation the gas bubbles carried along with the coolant flow are separated before entering the reactor core or forced away into the external zones. For this purpose the coolant is radially guided into a plenum below the core and deflected to a tangential direction by means of flow guide elements. The flow runs spirally downwards. On the bubbles, during their dwell time in this channel, the buoyant force and a force towards the axis of symmetry of the tank are exerted. The major part of the coolant is directed into a radial direction by means of a guiding apparatus in the lower section of the channel and guided through a chimney in the plenum to the center of the reactor core. This inner chimney is enclosed by an outer chimney for the core edge zones through which coolant with a small share of bubbles is taken away. (RW) [de

  2. Heat transfer experiments and correlations for natural and forced circulations of water in rod bundles at low Reynolds numbers

    International Nuclear Information System (INIS)

    Kim, Sung-Ho; El-Genk, Mohamed S.; Rubio, Reuben A.; Bryson, James W.; Foushee, Fabian C.

    1988-01-01

    Experimental heat transfer studies were conducted for fully developed forced and natural flows of water through seven uniformly heated rod bundles, triangularly arrayed with P/D = 1.25, 1.38, and 1.5. In forced circulation experiments, Re ranged from 80 to 50,000 and Pr from 3 to 8.5, while in natural circulation, Re varied from 260 to 2,000, and Ra q from 8 x 10 8 to 2.5 x 10 8 . The forced flow data fell into the two basic flow regimes: turbulent and laminar flow. At the transition between these regimes, Re, which varied from 2,200 for P/D = 1.25 to 5,500 for P/D = 1.5, increased linearly with P/D. The heat transfer data for turbulent flow was within ±15 percent of Weisman's correlation, which was developed for fully developed turbulent flow in rod bundles at Re > 25,000. The laminar flow data showed the dependence of Nu on Re to be weaker than that for turbulent flow, but the exponent of Re increased with P/D: Nu = A Re B Pr 1/3 , where A is equal to 1.061, 0.511, and 0.346 for P/D = 1.25, 1.38 and 1.5, respectively, and B is a linear function of P/D (B = 0.797 P/D - 0.656). Natural circulation data indicated that rod spacing only slightly affected heat transfer, and Nu increased proportionally to Ra 0.25 ; Nu = 0.272 Ra q 0.25 . The application of the results to SNL's ACRR indicated that although the core is cooled by natural convection, either the natural circulation correlation or the forced turbulent flow correlation can be used to accurately predict the single phase heat transfer coefficient in the ACRR. These results were concluded because of the high Rayleigh and Reynolds numbers in the ACRR. The ACRR operates near the boundary between mixed and forced turbulent flow regimes: consequently, achieving the high heat transfer coefficient was possible with natural circulation. (author)

  3. The mechanisms underlying corrosion product formation and deposition in nuclear power plant circuits through the action of galvanic and thermal electromotive forces

    International Nuclear Information System (INIS)

    Brusakov, V.P.; Sedov, V.M.; Khitrov, Yu.A.; Brusov, K.N.; Razmashkin, N.V.; Versin, V.V.; Rybalchenko, I.L.

    1983-01-01

    From a theoretical standpoint, the processes of formation of corrosion products in nuclear power plant circuits, deposition of corrosion products on the circuit surfaces, formation of an equilibrium concentration of corrosion products in the coolant, and distribution of radionuclides resulting from corrosion in different parts of the circuit are considered. It is shown that the main driving forces for the mass-transfer processes in the circuits are the thermal and galvanic electromotive forces (EMF) of the microcouples. On the basis of the theoretical concepts developed the authors have obtained analytical dependences for calculating the individual stages of the process of corrosion product transfer in the circuits. The mechanisms underlying the processes which occur as a result of thermal and galvanic EMFs are considered, together with the factors influencing these processes. The results of verification of the dependences by computational methods are given and they are compared with operational data from nuclear and conventional thermal power plants and with experimental data. (author)

  4. Development of force sensing circuit to determine the optimal force required for effective dynamic tripod grip/writing

    Science.gov (United States)

    Suraj S., S.; Kulkarni, Palash; Bokadia, Pratik; Ramanathan, Prabhu; Nageswaran, Sharmila

    2018-04-01

    Handwriting is a combination of fine motor perceptions and cognitive skills to produce words on paper. For writing, the most commonly used and recommended grip is the dynamic tripod grip. A child's handwriting starts developing during the times of pre-schooling and improves over time. While writing, children apply excessive force on the writing instrument. This force is exerted by their fingers and as per the law of reaction, the writing instruments tend to exert an equal and opposite force, that could damage the delicate soft tissue structures in their fingers and initiate cramps and pains. This condition is also prevalent in adults who tend to write for long hours under pressure. An example would be adolescence student during the exams. Clinically this condition is termed as `Writer's Cramp', which is usually characterized by muscle fatigue and pain in the fingers. By understanding and fixing the threshold of the force that should be exerted by the fingers while gripping the instrument, the pain can be controlled or avoided. This research aims in designing an electronic module which can help in understanding the threshold of pressure which is optimum enough to establish a better contact between the fingers and the instrument and should be capable of controlling or avoiding the pain. The design of FSR based electronic system is explained with its circuitry and results of initial testing is presented in this paper.

  5. Midlatitude Forcing Mechanisms for Glacier Mass Balance Investigated Using General Circulation Models

    NARCIS (Netherlands)

    Reichert, B.K.; Bengtsson, L.; Oerlemans, J.

    2001-01-01

    A process-oriented modeling approach is applied in order to simulate glacier mass balance for individual glaciers using statistically downscaled general circulation models (GCMs). Glacier-specific seasonal sensitivity characteristics based on a mass balance model of intermediate complexity are used

  6. A Novel Design Method for Optimizing an Indirect Forced Circulation Solar Water Heating System Based on Life Cycle Cost Using a Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Myeong Jin Ko

    2015-10-01

    Full Text Available To maximize the energy performance and economic benefits of solar water heating (SWH systems, the installation and operation-related design variables as well as those related to capacity must be optimized. This paper presents a novel design method for simultaneously optimizing the various design variables of an indirect forced-circulation SWH system that is based on the life cycle cost and uses a genetic algorithm. The effectiveness of the proposed method is assessed by evaluating the long-term performance corresponding to four cases, which are optimized using different annual solar fractions and sets of the design variables. When the installation and operation-related design variables were taken into consideration, it resulted in an efficient and economic design and an extra cost reduction of 3.2%–6.1% over when only the capacity-related design variables were considered. In addition, the results of parametric studies show that the slope and mass flow rate of the collector have a significant impact on the energy and economic performances of SWH systems. In contrast, the mass flow rate in the secondary circuit and the differences in the temperatures of the upper and lower dead bands of the differential controller have a smaller impact.

  7. Influence of various forcings on global climate in historical times using a coupled atmosphere-ocean general circulation model

    DEFF Research Database (Denmark)

    Stendel, Martin; Mogensen, Irene A.; Christensen, Jens H.

    2006-01-01

    The results of a simulation of the climate of the last five centuries with a state-of-the-art coupled atmosphere-ocean general circulation model are presented. The model has been driven with most relevant forcings, both natural (solar variability, volcanic aerosol) and anthropogenic (greenhouse...... gases, sulphate aerosol, land-use changes). In contrast to previous GCM studies, we have taken into account the latitudinal dependence of volcanic aerosol and the changing land cover for a period covering several centuries. We find a clear signature of large volcanic eruptions in the simulated...

  8. A numerical modeling study of the interaction between the tides and the circulation forced by high-latitude plasma convection

    International Nuclear Information System (INIS)

    Mikkelsen, I.S.; Larsen, M.F.

    1991-01-01

    A spectral, time-varying thermospheric general circulation model has been used to study the nonlinear interaction at high latitudes between the tides propagating into the thermosphere from below and the circulation induced by magnetospheric forcing and in situ solar heating. The model is discrete in the vertical with 27 layers spaced by half a scale height. In the horizontal, the fields are expanded in a series of spherical harmonics using a triangular truncation at wave number 31, equivalent to a homogeneous global resolution with a minimum wavelength of 1,270 km. A hypothetical uniform grid point model would require a horizontal spacing of 417 km to describe the same minimum wavelength. In the high-latitude F region the tides affect the dusk vortex of the neutral flow very little, but the dawn vortex is either suppressed or amplified dependent upon the universal time and tidal phase. In the E region neutral flow, both the dusk and dawn vortices are shifted in local time by the tides, again as a function of universal time and tidal phase. At dusk a nonlinear amplification of the sunward winds occurs for certain combination of parameters, and at dawn the winds may be completely suppressed. Below 120 km altitude the magnetospheric forcing creates a single cyclonic vortex which is also sensitive to the high-latitude tidal structure

  9. A zonally symmetric model for the monsoon-Hadley circulation with stochastic convective forcing

    Science.gov (United States)

    De La Chevrotière, Michèle; Khouider, Boualem

    2017-02-01

    Idealized models of reduced complexity are important tools to understand key processes underlying a complex system. In climate science in particular, they are important for helping the community improve our ability to predict the effect of climate change on the earth system. Climate models are large computer codes based on the discretization of the fluid dynamics equations on grids of horizontal resolution in the order of 100 km, whereas unresolved processes are handled by subgrid models. For instance, simple models are routinely used to help understand the interactions between small-scale processes due to atmospheric moist convection and large-scale circulation patterns. Here, a zonally symmetric model for the monsoon circulation is presented and solved numerically. The model is based on the Galerkin projection of the primitive equations of atmospheric synoptic dynamics onto the first modes of vertical structure to represent free tropospheric circulation and is coupled to a bulk atmospheric boundary layer (ABL) model. The model carries bulk equations for water vapor in both the free troposphere and the ABL, while the processes of convection and precipitation are represented through a stochastic model for clouds. The model equations are coupled through advective nonlinearities, and the resulting system is not conservative and not necessarily hyperbolic. This makes the design of a numerical method for the solution of this system particularly difficult. Here, we develop a numerical scheme based on the operator time-splitting strategy, which decomposes the system into three pieces: a conservative part and two purely advective parts, each of which is solved iteratively using an appropriate method. The conservative system is solved via a central scheme, which does not require hyperbolicity since it avoids the Riemann problem by design. One of the advective parts is a hyperbolic diagonal matrix, which is easily handled by classical methods for hyperbolic equations, while

  10. Remarkable separability of circulation response to Arctic sea ice loss and greenhouse gas forcing

    Science.gov (United States)

    McCusker, K. E.; Kushner, P. J.; Fyfe, J. C.; Sigmond, M.; Kharin, V. V.; Bitz, C. M.

    2017-08-01

    Arctic sea ice loss may influence midlatitude climate by changing large-scale circulation. The extent to which climate change can be understood as greenhouse gas-induced changes that are modulated by this loss depends on how additive the responses to the separate influences are. A novel sea ice nudging methodology in a fully coupled climate model reveals that the separate effects of doubled atmospheric carbon dioxide (CO2) concentrations and associated Arctic sea ice loss are remarkably additive and insensitive to the mean climate state. This separability is evident in several fields throughout most of the year, from hemispheric to synoptic scales. The extent to which the regional response to sea ice loss sometimes agrees with and sometimes cancels the response to CO2 is quantified. The separability of the responses might provide a means to better interpret the diverse array of modeling and observational studies of Arctic change and influence.

  11. Sensitivity of modeled estuarine circulation to spatial and temporal resolution of input meteorological forcing of a cold frontal passage

    Science.gov (United States)

    Weaver, Robert J.; Taeb, Peyman; Lazarus, Steven; Splitt, Michael; Holman, Bryan P.; Colvin, Jeffrey

    2016-12-01

    In this study, a four member ensemble of meteorological forcing is generated using the Weather Research and Forecasting (WRF) model in order to simulate a frontal passage event that impacted the Indian River Lagoon (IRL) during March 2015. The WRF model is run to provide high and low, spatial (0.005° and 0.1°) and temporal (30 min and 6 h) input wind and pressure fields. The four member ensemble is used to force the Advanced Circulation model (ADCIRC) coupled with Simulating Waves Nearshore (SWAN) and compute the hydrodynamic and wave response. Results indicate that increasing the spatial resolution of the meteorological forcing has a greater impact on the results than increasing the temporal resolution in coastal systems like the IRL where the length scales are smaller than the resolution of the operational meteorological model being used to generate the forecast. Changes in predicted water elevations are due in part to the upwind and downwind behavior of the input wind forcing. The significant wave height is more sensitive to the meteorological forcing, exhibited by greater ensemble spread throughout the simulation. It is important that the land mask, seen by the meteorological model, is representative of the geography of the coastal estuary as resolved by the hydrodynamic model. As long as the temporal resolution of the wind field captures the bulk characteristics of the frontal passage, computational resources should be focused so as to ensure that the meteorological model resolves the spatial complexities, such as the land-water interface, that drive the land use responsible for dynamic downscaling of the winds.

  12. Dynamical and statistical phenomena of circulation and heat transfer in periodically forced rotating turbulent Rayleigh-Bénard convection

    Science.gov (United States)

    Sterl, Sebastian; Li, Hui-Min; Zhong, Jin-Qiang

    2016-12-01

    In this paper, we present results from an experimental study into turbulent Rayleigh-Bénard convection forced externally by periodically modulated unidirectional rotation rates. We find that the azimuthal rotation velocity θ ˙(t ) and thermal amplitude δ (t ) of the large-scale circulation (LSC) are modulated by the forcing, exhibiting a variety of dynamics including increasing phase delays and a resonant peak in the amplitude of θ ˙(t ) . We also focus on the influence of modulated rotation rates on the frequency of occurrence η of stochastic cessation or reorientation events, and on the interplay between such events and the periodically modulated response of θ ˙(t ) . Here we identify a mechanism by which η can be amplified by the modulated response, and these normally stochastic events can occur with high regularity. We provide a modeling framework that explains the observed amplitude and phase responses, and we extend this approach to make predictions for the occurrence of cessation events and the probability distributions of θ ˙(t ) and δ (t ) during different phases of a modulation cycle, based on an adiabatic approach that treats each phase separately. Last, we show that such periodic forcing has consequences beyond influencing LSC dynamics, by investigating how it can modify the heat transport even under conditions where the Ekman pumping effect is predominant and strong enhancement of heat transport occurs. We identify phase and amplitude responses of the heat transport, and we show how increased modulations influence the average Nusselt number.

  13. Forced-circulation solar water heater using a solar battery; Taiyo denchi wo mochiita kyosei junkahshiki taiyonetsu onsuiki

    Energy Technology Data Exchange (ETDEWEB)

    Asai, S; Mizuno, T [Yazaki Corp., Tokyo (Japan)

    1997-11-25

    Optimal operation control was discussed on a forced-circulation solar water heater using solar cells not only as the power supply of a heat collecting pump, but also for controlling operation of the heat collecting pump. With this system, when the amount of power generated by solar cells reaches a sufficient level for operating the heat collecting pump, the heat collecting pump starts operation, wherein the heat collecting medium circulates in the system. The discussion was given by using simulation based on experimental expressions such as the relation expression between insolation and heat collecting medium flow rate as derived from the result of the system`s heat collecting performance test. As a result, the following conclusions were obtained: optimal insolation for activating the discussed system is from 50 to 100 W/m {sup 2}, and the heat collected within this range is within -1.5% of the collected heat amount at an optimum value; optimal activating insolation for the case of 1000 to 2000 W/m {sup 2} with low daily cumulative insolation is from 0 to 50 W/m {sup 2}, whereas the optimal activating insolation amount increases as the daily cumulative insolation amount increases; and the optimal activating insolation amount increases as water to be supplied requires higher temperature. 1 ref., 17 figs., 2 tabs.

  14. Evaluation on driving force of natural circulation in downcomer for passive residual heat removal system in JAERI passive safety reactor JPSR

    International Nuclear Information System (INIS)

    Kunii, Katsuhiko; Iwamura, Takamichi; Murao, Yoshio

    1997-01-01

    The driving-force of the natural circulation in the residual heat removal (RHR) system for the JPSR (JAERI Passive Safety Reactor) is given as a gravity force of the density difference between hotter coolant in core and upper plenum and cooler coolant in downcomer. The amount of density difference and time to achieve the enough density difference for the RHR system change directly dependent on the thermal fluid flow pattern in downcomer of annulus flow pass. The purposes of the present study are to investigate the possibilities of the followings by evaluating the three-dimensional thermal fluid flow in downcomer by numerical analysis using the STREAM code; 1) promotion of making the flow pattern uniform in downcomer by installing a baffle, 2) achievement of an enough driving-force of the natural circulation, 3) validity of one-point assumption, that is, complete mixing down-flow assumption for the three-dimensional thermal fluid flow in downcomer to evaluate the function of the passive RHR system. The following conclusions were obtained: (1) The effect of baffle on the thermal fluid flow and driving-force is little, (2) The driving-force required for natural circulation cooling can be obtained in wide range of inlet velocity even if the flow is multi-dimensional, (3) Both in initial transient stage and in steady-state, the one-point assumption can be applied to evaluate the driving-force of natural circulation in the passive RHR system. (author)

  15. The subpolar North Atlantic - Response to North Atlantic oscillation like forcing and Influence on the Atlantic meridional overturning circulation

    Science.gov (United States)

    Lohmann, Katja; Drange, Helge; Jungclaus, Johann

    2010-05-01

    The extent and strength of the North Atlantic subpolar gyre (SPG) changed rapidly in the mid-1990s, going from large and strong in 1995 to substantially weakened in the following years. The abrupt change in the intensity of the SPG is commonly linked to the reversal of the North Atlantic Oscillation (NAO) index, changing from strong positive to negative values, in the winter 1995/96. In this study we investigate the impact of the initial SPG state on its subsequent behavior by means of an ocean general circulation model driven by NCEP-NCAR reanalysis fields. Our sensitivity integrations suggest that the weakening of the SPG cannot be explained by the change in the atmospheric forcing alone. Rather, for the time period around 1995, the SPG was about to weaken, irrespective of the actual atmospheric forcing, due to the ocean state governed by the persistently strong positive NAO during the preceding seven years (1989 to 1995). Our analysis indicates that it was this preconditioning of the ocean, in combination with the sudden drop in the NAO in 1995/96, that lead to the strong and rapid weakening of the SPG in the second half of the 1990s. In the second part, the sensitivity of the low-frequency variability of the Atlantic meridional overturning circulation to changes in the subpolar North Atlantic is investigated using a 2000 year long control integration as well as sensitivity experiments with the MPI-M Earth System Model. Two 1000 year long sensitivity experiments will be performed, in which the low-frequency variability in the overflow transports from the Nordic Seas and in the subpolar deep water formation rates is suppressed respectively. This is achieved by nudging temperature and salinity in the GIN Sea or in the subpolar North Atlantic (up to about 1500m depth) towards a monthly climatology obtained from the last 1000 years of the control integration.

  16. The influence of cirrus cloud-radiative forcing on climate and climate sensitivity in a general circulation model

    International Nuclear Information System (INIS)

    Lohmann, U.; Roeckner, E.

    1994-01-01

    Six numerical experiments have been performed with a general circulation model (GCM) to study the influence of high-level cirrus clouds and global sea surface temperature (SST) perturbations on climate and climate sensitivity. The GCM used in this investigation is the third-generation ECHAM3 model developed jointly by the Max-Planck-Institute for Meteorology and the University of Hamburg. It is shown that the model is able to reproduce many features of the observed cloud-radiative forcing with considerable skill, such as the annual mean distribution, the response to seasonal forcing and the response to observed SST variations in the equatorial Pacific. In addition to a reference experiment where the cirrus emissivity is computed as a function of the cloud water content, two sensitivity experiments have been performed in which the cirrus emissivity is either set to zero everywhere above 400 hPa ('transparent cirrus') or set to one ('black cirrus'). These three experiments are repeated identically, except for prescribing a globally uniform SST warming of 4 K. (orig.)

  17. 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.)

  18. 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

  19. 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.

  20. Seasonal overturning circulation in the Red Sea: 2. Winter circulation

    KAUST Repository

    Yao, Fengchao; Hoteit, Ibrahim; Pratt, Lawrence J.; Bower, Amy S.; Kö hl, Armin; Gopalakrishnan, Ganesh; Rivas, David

    2014-01-01

    The shallow winter overturning circulation in the Red Sea is studied using a 50 year high-resolution MITgcm (MIT general circulation model) simulation with realistic atmospheric forcing. The overturning circulation for a typical year, represented

  1. Some didactical suggestions for a deeper embedding of DC circuits into electromagnetism

    International Nuclear Information System (INIS)

    Cavinato, M; Giliberti, M; Barbieri, S R

    2017-01-01

    Undergraduate students often encounter great difficulties in understanding Ohm’s law and electrical circuits. Considering the widespread students’ beliefs and their common mistakes, as they come out from the literature and our teaching experience, we think that a relevant source of these problems comes from the fact that electrical circuits are generally treated separately from the other topics of electromagnetism, with poor reference to the circulation of the electric field. We present here a way to deal with electrical circuits that could help students to overcome their difficulties. In our approach, the electric field is the protagonist and the mathematical tool the students are asked to use is its circulation. In the light of the circulation of the electric field, the experimental Ohm’s law is revisited, the concept of electromotive force is discussed and some suggestions to eliminate common misconceptions about the role of a battery in a circuit are presented. (paper)

  2. Some didactical suggestions for a deeper embedding of DC circuits into electromagnetism

    Science.gov (United States)

    Cavinato, M.; Giliberti, M.; Barbieri, S. R.

    2017-09-01

    Undergraduate students often encounter great difficulties in understanding Ohm’s law and electrical circuits. Considering the widespread students’ beliefs and their common mistakes, as they come out from the literature and our teaching experience, we think that a relevant source of these problems comes from the fact that electrical circuits are generally treated separately from the other topics of electromagnetism, with poor reference to the circulation of the electric field. We present here a way to deal with electrical circuits that could help students to overcome their difficulties. In our approach, the electric field is the protagonist and the mathematical tool the students are asked to use is its circulation. In the light of the circulation of the electric field, the experimental Ohm’s law is revisited, the concept of electromotive force is discussed and some suggestions to eliminate common misconceptions about the role of a battery in a circuit are presented.

  3. Reverse Estuarine Circulation Due to Local and Remote Wind Forcing, Enhanced by the Presence of Along-Coast Estuaries

    Science.gov (United States)

    Giddings, S. N.; MacCready, P.

    2017-12-01

    Estuarine exchange flow governs the interaction between oceans and estuaries and thus plays a large role in their biogeochemical processes. This study investigates the variability in estuarine exchange flow due to offshore oceanic conditions including upwelling/downwelling, and the presence of a river plume offshore (from a neighboring estuary). We address these processes via numerical simulations at the mouth of the Salish Sea, a large estuarine system in the Northeast Pacific. An analysis of the Total Exchange Flow indicates that during the upwelling season, the exchange flow is fairly consistent in magnitude and oriented in a positive (into the estuary at depth and out at the surface) direction. However, during periods of downwelling favorable winds, the exchange flow shows significantly more variability including multiple reversals, consistent with observations, and surface intrusions of the Columbia River plume which originates 250 km to the south. Numerical along-strait momentum budgets show that the exchange flow is forced dominantly by the pressure gradients, particularly the baroclinic. The pressure gradient is modified by Coriolis and sometimes advection, highlighting the importance of geostrophy and local adjustments. In experiments conducted without the offshore river plume, reversals still occur but are weaker, and the baroclinic pressure gradient plays a reduced role. These results suggest that estuaries along strong upwelling coastlines should experience significant modulation in the exchange flow during upwelling versus downwelling conditions. Additionally, they highlight the importance of nearby estuaries impacting one-another, not only in terms of connectivity, but also altering the exchange flow.Plain Language SummaryEstuarine systems provide extensive biological and ecological functions as well as contribute to human uses and economies. However, estuaries are susceptible to change and most estuaries have been significantly impacted, threatening

  4. Experimental study of core thermohydraulics in fast reactors during transition from forced to natural circulation. Influence of inter-wrapper flow

    International Nuclear Information System (INIS)

    Kamide, H.; Hayashi, K.; Momoi, K.

    1997-01-01

    The evaluation of core thermohydraulics under natural circulation conditions is important to utilize inherent safety features of Fast Reactors. When heat exchangers of a decay heat removal system are operated in an upper plenum of reactor vessel, cold sodium is provided by the heat exchangers. Core-plenum interactions will occur during a natural circulation condition due to this cold sodium in the upper plenum, e.g., it can penetrate into gap regions between fuel subassemblies (inter-wrapper flow, IWF) and the flow may reverse in low power core channels. These interactions will significantly modify the flow and temperature distributions in the core. Sodium experiments were carried out to study these phenomena. In a test section, seven subassemblies are housed and connected to an upper plenum. The influences of core-plenum interactions on the core thermohydraulics were investigated under steady state conditions and also in transitions from forced to natural circulation. Cooling effects of IWF on the fuel subassemblies were found in spite of natural circulation flow reduction in the primary loop due to temperature decreases in the upper non-heated section in the core. The inter-wrapper flow can effectively cool the core under extreme conditions of low flow rates through the core. (author)

  5. Benchmark analysis of three main circulation pump sequential trip event at Ignalina NPP

    International Nuclear Information System (INIS)

    Uspuras, E.; Kaliatka, A.; Urbonas, R.

    2001-01-01

    The Ignalina Nuclear Power Plant is a twin-unit with two RBMK-1500 reactors. The primary circuit consists of two symmetrical loops. Eight Main Circulation Pumps (MCPs) at the Ignalina NPP are employed for the coolant water forced circulation through the reactor core. The MCPs are joined in groups of four pumps for each loop (three for normal operation and one on standby). This paper presents the benchmark analysis of three main circulation pump sequential trip event at RBMK-1500 using RELAP5 code. During this event all three MCPs in one circulation loop at Unit 2 Ignalina NPP were tripped one after another, because of inadvertent activation of the fire protection system. The comparison of calculated and measured parameters led us to establish realistic thermal hydraulic characteristics of different main circulation circuit components and to verify the model of drum separators pressure and water level controllers.(author)

  6. A 40 GHz fully integrated circuit with a vector network analyzer and a coplanar-line-based detection area for circulating tumor cell analysis using 65 nm CMOS technology

    Science.gov (United States)

    Nakanishi, Taiki; Matsunaga, Maya; Kobayashi, Atsuki; Nakazato, Kazuo; Niitsu, Kiichi

    2018-03-01

    A 40-GHz fully integrated CMOS-based circuit for circulating tumor cells (CTC) analysis, consisting of an on-chip vector network analyzer (VNA) and a highly sensitive coplanar-line-based detection area is presented in this paper. In this work, we introduce a fully integrated architecture that eliminates unwanted parasitic effects. The proposed analyzer was designed using 65 nm CMOS technology, and SPICE and MWS simulations were used to validate its operation. The simulation confirmed that the proposed circuit can measure S-parameter shifts resulting from the addition of various types of tumor cells to the detection area, the data of which are provided in a previous study: the |S 21| values for HepG2, A549, and HEC-1-A cells are -0.683, -0.580, and -0.623 dB, respectively. Additionally, the measurement demonstrated an S-parameters reduction of -25.7% when a silicone resin was put on the circuit. Hence, the proposed system is expected to contribute to cancer diagnosis.

  7. The Role of Subtropical Irreversible PV Mixing in the Zonal Mean Circulation Response to Global Warming-like Thermal Forcing

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sun, Lantao [National Center for Atmospheric Research, Boulder, CO (United States); Wu, Yutian [New York Univ. (NYU), NY (United States); Chen, Gang [Cornell Univ., Ithaca, NY (United States)

    2013-11-21

    The atmospheric circulation response to the global warming-like tropical upper tropospheric heating is revisited using a dry atmospheric general circulation model (AGCM) in light of a new diagnostics based on the concept of finite-amplitude wave activity (FAWA) on equivalent latitude. For a given tropical heating profile, the linear Wentzel-Kramers-Brillouin (WKB) wave refraction analysis sometimes gives a very different and even opposite prediction of the eddy momentum flux response to that of the actual full model simulation, exposing the limitation of the traditional linear approach in understanding the full dynamics of the atmospheric response under global warming. The implementation of the FAWA diagnostics reveals that in response to the upper tropospheric heating, effective diffusivity, a measure of the mixing efficiency, increases and advances upward and poleward in the subtropics and the resultant enhancement and the poleward encroachment of eddy potential vorticity mixing leads to a poleward displaced potential vorticity (PV) gradient peak in the upper troposphere. The anomalous eddy PV flux, in balance with the PV dissipation, gives rise to a poleward shift in the eddy-driven jet and eddy-driven mean meridional circulation. Sensitivity experiments show that these irreversible dissipation processes in the upper troposphere are robust, regardless of the width of the tropical heating.

  8. Influence of forced internal air circulation on airflow distribution and heat transfer in a gas double-dynamic solid-state fermentation bioreactor.

    Science.gov (United States)

    Chen, Hongzhang; Qin, Lanzhi; Li, Hongqiang

    2014-02-01

    Internal air circulation affects the temperature field distribution in a gas double-dynamic solid-state fermentation bioreactor (GDSFB). To enhance heat transfer through strengthening internal air circulation in a GDSFB, we put an air distribution plate (ADP) into the bioreactor and studied the effects of forced internal air circulation on airflow, heat transfer, and cellulase activity of Trichoderma viride L3. Results showed that ADP could help form a steady and uniform airflow distribution, and with gas-guide tubes, air reversal was formed inside the bioreactor, thus resulting in a smaller temperature difference between medium and air by enhancing convective heat transfer inside the bioreactor. Using an ADP of 5.35 % aperture ratio caused a 1 °C decrease in the average temperature difference during the solid-state fermentation process of T. viride L3. Meanwhile, the cellulase activity of T. viride L3 increased by 13.5 %. The best heat-transfer effect was attained when using an ADP of 5.35 % aperture ratio and setting the fan power to 125 V (4.81 W) in the gas double-dynamic solid-state fermentation (GDSF) process. An option of suitable aperture ratio and fan power may be conducive to ADPs' industrial amplification.

  9. Thermohaline forcing of eastern boundary currents: With application to the circulation off the west coast of Australia

    Digital Repository Service at National Institute of Oceanography (India)

    Mc; Shetye, S.R.; Kundu, P.K.

    The linear, viscid, continuously stratified model of McCreary (1981) is extended to allow for thermohaline forcing by a specified, longitudinally independent, surface density field @ips@@. When the ocean is unbounded and @ips@@ is steady...

  10. Modes of interannual variability in northern hemisphere winter atmospheric circulation in CMIP5 models: evaluation, projection and role of external forcing

    Science.gov (United States)

    Frederiksen, Carsten S.; Ying, Kairan; Grainger, Simon; Zheng, Xiaogu

    2018-04-01

    Models from the coupled model intercomparison project phase 5 (CMIP5) dataset are evaluated for their ability to simulate the dominant slow modes of interannual variability in the Northern Hemisphere atmospheric circulation 500 hPa geopotential height in the twentieth century. A multi-model ensemble of the best 13 models has then been used to identify the leading modes of interannual variability in components related to (1) intraseasonal processes; (2) slowly-varying internal dynamics; and (3) the slowly-varying response to external changes in radiative forcing. Modes in the intraseasonal component are related to intraseasonal variability in the North Atlantic, North Pacific and North American, and Eurasian regions and are little affected by the larger radiative forcing of the Representative Concentration Pathways 8.5 (RCP8.5) scenario. The leading modes in the slow-internal component are related to the El Niño-Southern Oscillation, Pacific North American or Tropical Northern Hemisphere teleconnection, the North Atlantic Oscillation, and the Western Pacific teleconnection pattern. While the structure of these slow-internal modes is little affected by the larger radiative forcing of the RCP8.5 scenario, their explained variance increases in the warmer climate. The leading mode in the slow-external component has a significant trend and is shown to be related predominantly to the climate change trend in the well mixed greenhouse gas concentration during the historical period. This mode is associated with increasing height in the 500 hPa pressure level. A secondary influence on this mode is the radiative forcing due to stratospheric aerosols associated with volcanic eruptions. The second slow-external mode is shown to be also related to radiative forcing due to stratospheric aerosols. Under RCP8.5 there is only one slow-external mode related to greenhouse gas forcing with a trend over four times the historical trend.

  11. Future discharge drought across climate regions around the world modelled with a synthetic hydrological modelling approach forced by three general circulation models

    Science.gov (United States)

    Wanders, N.; Van Lanen, H. A. J.

    2015-03-01

    Hydrological drought characteristics (drought in groundwater and streamflow) likely will change in the 21st century as a result of climate change. The magnitude and directionality of these changes and their dependency on climatology and catchment characteristics, however, is uncertain. In this study a conceptual hydrological model was forced by downscaled and bias-corrected outcome from three general circulation models for the SRES A2 emission scenario (GCM forced models), and the WATCH Forcing Data set (reference model). The threshold level method was applied to investigate drought occurrence, duration and severity. Results for the control period (1971-2000) show that the drought characteristics of each GCM forced model reasonably agree with the reference model for most of the climate types, suggesting that the climate models' results after post-processing produce realistic outcomes for global drought analyses. For the near future (2021-2050) and far future (2071-2100) the GCM forced models show a decrease in drought occurrence for all major climates around the world and increase of both average drought duration and deficit volume of the remaining drought events. The largest decrease in hydrological drought occurrence is expected in cold (D) climates where global warming results in a decreased length of the snow season and an increased precipitation. In the dry (B) climates the smallest decrease in drought occurrence is expected to occur, which probably will lead to even more severe water scarcity. However, in the extreme climate regions (desert and polar), the drought analysis for the control period showed that projections of hydrological drought characteristics are most uncertain. On a global scale the increase in hydrological drought duration and severity in multiple regions will lead to a higher impact of drought events, which should motivate water resource managers to timely anticipate the increased risk of more severe drought in groundwater and streamflow

  12. Circulation pump mounting

    International Nuclear Information System (INIS)

    Skalicky, A.

    1976-01-01

    The suspension is described of nuclear reactor circulating pumps enabling their dilatation with a minimum reverse force consisting of spacing rods supported with one end in the anchor joints and provided with springs and screw joints engaging the circulating pump shoes. The spacing rods are equipped with side vibration dampers anchored in the shaft side wall and on the body of the circulating pump drive body. The negative reverse force F of the spacing rods is given by the relation F=Q/l.y, where Q is the weight of the circulating pump, l is the spatial distance between the shoe joints and anchor joints, and y is the deflection of the circulating pump vertical axis from the mean equilibrium position. The described suspension is advantageous in that that the reverse force for the deflection from the mean equilibrium position is minimal, dynamic behaviour is better, and construction costs are lower compared to suspension design used so far. (J.B.)

  13. 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

  14. Respective roles of direct GHG radiative forcing and induced Arctic sea ice loss on the Northern Hemisphere atmospheric circulation

    Science.gov (United States)

    Oudar, Thomas; Sanchez-Gomez, Emilia; Chauvin, Fabrice; Cattiaux, Julien; Terray, Laurent; Cassou, Christophe

    2017-12-01

    The large-scale and synoptic-scale Northern Hemisphere atmospheric circulation responses to projected late twenty-first century Arctic sea ice decline induced by increasing Greenhouse Gases (GHGs) concentrations are investigated using the CNRM-CM5 coupled model. An original protocol, based on a flux correction technique, allows isolating the respective roles of GHG direct radiative effect and induced Arctic sea ice loss under RCP8.5 scenario. In winter, the surface atmospheric response clearly exhibits opposing effects between GHGs increase and Arctic sea ice loss, leading to no significant pattern in the total response (particularly in the North Atlantic region). An analysis based on Eady growth rate shows that Arctic sea ice loss drives the weakening in the low-level meridional temperature gradient, causing a general decrease of the baroclinicity in the mid and high latitudes, whereas the direct impact of GHGs increase is more located in the mid-to-high troposphere. Changes in the flow waviness, evaluated from sinuosity and blocking frequency metrics, are found to be small relative to inter-annual variability.

  15. Forced-circulation solar water heater using a solar battery; Taiyo denchi wo mochiita kyosei junkanshiki taiyonetsu onsuiki

    Energy Technology Data Exchange (ETDEWEB)

    Asai, S; Mizuno, T [Yazaki Resources Co. Ltd., Shizuoka (Japan)

    1996-10-27

    For the purpose of satisfying demands for qualitative improvement on tapwater temperature and pressure, an indirect-type solar water heater using solar cells, in which a closed type hot water storage tank connected directly to the water supply is integrated with a solar collector, was examined for its characteristics and performance. The heat collecting medium is a water solution of polypropylene glycol, which circulates through the solar collector pump, cistern, solar collector, and heat exchanger (hot water storage tank). The results of the test are summarized below. When comparison is made between the two solar collector pump control methods, the solar cells direct connection method and the differential thermo method utilizing temperature difference between the solar collector and the hot water storage tank, they are alike in collecting heat on clear days, but on cloudy days the latter collects 5% more than the former. In winter, when the heat exchanger heat transfer area is 0.4m{sup 2} large, a further increase in the area improves but a little the heat collecting efficiency. An increase in the medium flow rate and temperature, or in the Reynolds number, enhances the heat collecting efficiency. 13 figs., 6 tabs.

  16. Assessment of Southern Ocean water mass circulation and characteristics in CMIP5 models: Historical bias and forcing response

    Science.gov (United States)

    Sallée, J.-B.; Shuckburgh, E.; Bruneau, N.; Meijers, A. J. S.; Bracegirdle, T. J.; Wang, Z.; Roy, T.

    2013-04-01

    The ability of the models contributing to the fifth Coupled Models Intercomparison Project (CMIP5) to represent the Southern Ocean hydrological properties and its overturning is investigated in a water mass framework. Models have a consistent warm and light bias spread over the entire water column. The greatest bias occurs in the ventilated layers, which are volumetrically dominated by mode and intermediate layers. The ventilated layers have been observed to have a strong fingerprint of climate change and to impact climate by sequestrating a significant amount of heat and carbon dioxide. The mode water layer is poorly represented in the models and both mode and intermediate water have a significant fresh bias. Under increased radiative forcing, models simulate a warming and lightening of the entire water column, which is again greatest in the ventilated layers, highlighting the importance of these layers for propagating the climate signal into the deep ocean. While the intensity of the water mass overturning is relatively consistent between models, when compared to observation-based reconstructions, they exhibit a slightly larger rate of overturning at shallow to intermediate depths, and a slower rate of overturning deeper in the water column. Under increased radiative forcing, atmospheric fluxes increase the rate of simulated upper cell overturning, but this increase is counterbalanced by diapycnal fluxes, including mixed-layer horizontal mixing, and mostly vanishes.

  17. 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

  18. 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

  19. The effect of Coriolis-Stokes forcing on upper ocean circulation in a two-way coupled wave-current model

    Institute of Scientific and Technical Information of China (English)

    DENG Zeng'an; XIE Li'an; HAN Guijun; ZHANG Xuefeng; WU Kejian

    2012-01-01

    We investigated the Stokes drift-driven ocean currents and Stokes drift-induced wind energy input into the upper ocean using a two-way coupled wave-current modeling system that consists of the Princeton Ocean Model generalized coordinate system (POMgcs),Simulating WAves Nearshore (SWAN) wave model,and the Model Coupling Toolkit (MCT).The Coriolis-Stokes forcing (CSF) computed using the wave parameters from SWAN was incorporated with the momentum equation of POMgcs as the core coupling process.Experimental results in an idealized setting show that under the steady state,the scale of the speed of CSF-driven current was 0.001 m/s and the maximum reached 0.02 rn/s.The Stokes drift-induced energy rate input into the model ocean was estimated to be 28.5 GW,taking 14% of the direct wind energy rate input.Considering the Stokes drift effects,the total mechanical energy rate input was increased by approximately 14%,which highlights the importance of CSF in modulating the upper ocean circulation.The actual run conducted in Taiwan Adjacent Sea (TAS) shows that:1) CSF-based wave-current coupling has an impact on ocean surface currents,which is related to the activities of monsoon winds; 2) wave-current coupling plays a significant role in a place where strong eddies present and tends to intensify the eddy's vorticity; 3) wave-current coupling affects the volume transport of the Taiwan Strait (TS) throughflow in a nontrivial degree,3.75% on average.

  20. Integrated coherent matter wave circuits

    International Nuclear Information System (INIS)

    Ryu, C.; Boshier, M. G.

    2015-01-01

    An integrated coherent matter wave circuit is a single device, analogous to an integrated optical circuit, in which coherent de Broglie waves are created and then launched into waveguides where they can be switched, divided, recombined, and detected as they propagate. Applications of such circuits include guided atom interferometers, atomtronic circuits, and precisely controlled delivery of atoms. We report experiments demonstrating integrated circuits for guided coherent matter waves. The circuit elements are created with the painted potential technique, a form of time-averaged optical dipole potential in which a rapidly moving, tightly focused laser beam exerts forces on atoms through their electric polarizability. Moreover, the source of coherent matter waves is a Bose-Einstein condensate (BEC). Finally, we launch BECs into painted waveguides that guide them around bends and form switches, phase coherent beamsplitters, and closed circuits. These are the basic elements that are needed to engineer arbitrarily complex matter wave circuitry

  1. 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.

  2. 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.

  3. 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.

  4. Containment air circulation for optimal hydrogen recombination

    International Nuclear Information System (INIS)

    Spinks, N.; Krause, M.

    1997-01-01

    An accepted first-line defense for hydrogen mitigation is to design for the hydrogen to be rapidly mixed with the containment atmosphere and diluted to below flammability concentrations. Then, as hydrogen continues to be produced in the longer term, recombiners can be used to remove hydrogen: recombiners can be located in forced-air ducts or passive recombiners can be distributed within containment and the heat of recombination used to promote local air circulation. However, this principle does not eliminate the possibility of high hydrogen concentrations at locations removed from the recombiners. An improvement on this strategy is to arrange for a specific, buoyancy-driven, overall circulation of the containment atmosphere such that the recombiners can be located within the recirculation flow, immediately downstream of the hydrogen source. This would make the mixing process more predictable and solve the mass-transfer problem associated with distributed recombiners. Ideally, the recombiners would be located just above the hydrogen source so that the heat of recombination would assist the overall circulation. In this way, the hydrogen would be removed as close as possible to the source, thereby minimizing the amount of hydrogen immediately downstream of the source and reducing the hydrogen concentration to acceptable levels at other locations. Such a strategy requires the containment volume to be divided into an upflow path, past the hydrogen source and the recombiner, and a downflow path to complete the circuit. The flow could be generated actively using fans or passively using buoyancy forces arising from the difference in density of gases in the upfiow and downflow paths; the gases in the downflow path being cooled at an elevated heat sink. (author)

  5. 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...

  6. 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)

  7. Variational integrators for electric circuits

    International Nuclear Information System (INIS)

    Ober-Blöbaum, Sina; Tao, Molei; Cheng, Mulin; Owhadi, Houman; Marsden, Jerrold E.

    2013-01-01

    In this contribution, we develop a variational integrator for the simulation of (stochastic and multiscale) electric circuits. When considering the dynamics of an electric circuit, one is faced with three special situations: 1. The system involves external (control) forcing through external (controlled) voltage sources and resistors. 2. The system is constrained via the Kirchhoff current (KCL) and voltage laws (KVL). 3. The Lagrangian is degenerate. Based on a geometric setting, an appropriate variational formulation is presented to model the circuit from which the equations of motion are derived. A time-discrete variational formulation provides an iteration scheme for the simulation of the electric circuit. Dependent on the discretization, the intrinsic degeneracy of the system can be canceled for the discrete variational scheme. In this way, a variational integrator is constructed that gains several advantages compared to standard integration tools for circuits; in particular, a comparison to BDF methods (which are usually the method of choice for the simulation of electric circuits) shows that even for simple LCR circuits, a better energy behavior and frequency spectrum preservation can be observed using the developed variational integrator

  8. Seasonal overturning circulation in the Red Sea: 2. Winter circulation

    Science.gov (United States)

    Yao, Fengchao; Hoteit, Ibrahim; Pratt, Larry J.; Bower, Amy S.; Köhl, Armin; Gopalakrishnan, Ganesh; Rivas, David

    2014-04-01

    The shallow winter overturning circulation in the Red Sea is studied using a 50 year high-resolution MITgcm (MIT general circulation model) simulation with realistic atmospheric forcing. The overturning circulation for a typical year, represented by 1980, and the climatological mean are analyzed using model output to delineate the three-dimensional structure and to investigate the underlying dynamical mechanisms. The horizontal model circulation in the winter of 1980 is dominated by energetic eddies. The climatological model mean results suggest that the surface inflow intensifies in a western boundary current in the southern Red Sea that switches to an eastern boundary current north of 24°N. The overturning is accomplished through a cyclonic recirculation and a cross-basin overturning circulation in the northern Red Sea, with major sinking occurring along a narrow band of width about 20 km along the eastern boundary and weaker upwelling along the western boundary. The northward pressure gradient force, strong vertical mixing, and horizontal mixing near the boundary are the essential dynamical components in the model's winter overturning circulation. The simulated water exchange is not hydraulically controlled in the Strait of Bab el Mandeb; instead, the exchange is limited by bottom and lateral boundary friction and, to a lesser extent, by interfacial friction due to the vertical viscosity at the interface between the inflow and the outflow.

  9. 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)

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Electronic circuit for control rod attracting electromagnet

    International Nuclear Information System (INIS)

    Ito, Koji.

    1991-01-01

    The present invention provides a discharging circuit for control rod attracting electromagnet used for a reactor which is highly reliable and has high performance. The resistor of the circuit comprises a non-linear resistor element and a blocking rectification element connected in series. The discharging circuit can be prevented from short-circuit by selecting a resistor having a resistance value about ten times as great as the coil resistance, even in a case where the blocking rectification element and the non-linear resistor element are failed. Accordingly, reduction of attracting force and the increase of scream releasing time can be minimized. (I.S.)

  15. Electric circuit theory applied electricity and electronics

    CERN Document Server

    Yorke, R

    1981-01-01

    Electric Circuit Theory provides a concise coverage of the framework of electrical engineering. Comprised of six chapters, this book emphasizes the physical process of electrical engineering rather than abstract mathematics. Chapter 1 deals with files, circuits, and parameters, while Chapter 2 covers the natural and forced response of simple circuit. Chapter 3 talks about the sinusoidal steady state, and Chapter 4 discusses the circuit analysis. The fifth chapter tackles frequency response of networks, and the last chapter covers polyphase systems. This book will be of great help to electrical

  16. Two-phase flow patterns recognition and parameters estimation through natural circulation test loop image analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita, R.N.; Libardi, R.M.P.; Masotti, P.H.F.; Sabundjian, G.; Andrade, D.A.; Umbehaun, P.E.; Torres, W.M.; Conti, T.N.; Macedo, L.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Nuclear Engineering Center], e-mail: rnavarro@ipen.br

    2009-07-01

    Visualization of natural circulation test loop cycles is used to study two-phase flow patterns associated with phase transients and static instabilities of flow. Experimental studies on natural circulation flow were originally related to accidents and transient simulations relative to nuclear reactor systems with light water refrigeration. In this regime, fluid circulation is mainly caused by a driving force ('thermal head') which arises from density differences due to temperature gradient. Natural circulation phenomenon has been important to provide residual heat removal in cases of 'loss of pump power' or plant shutdown in nuclear power plant accidents. The new generation of compact nuclear reactors includes natural circulation of their refrigerant fluid as a security mechanism in their projects. Two-phase flow patterns have been studied for many decades, and the related instabilities have been object of special attention recently. Experimental facility is an all glass-made cylindrical tubes loop which contains about twelve demineralized water liters, a heat source by an electrical resistor immersion heater controlled by a Variac, and a helicoidal heat exchanger working as cold source. Data is obtained through thermo-pairs distributed over the loop and CCD cameras. Artificial intelligence based algorithms are used to improve (bubble) border detection and patterns recognition, in order to estimate and characterize, phase transitions patterns and correlate them with the periodic static instability (chugging) cycle observed in this circuit. Most of initial results show good agreement with previous numerical studies in this same facility. (author)

  17. Two-phase flow patterns recognition and parameters estimation through natural circulation test loop image analysis

    International Nuclear Information System (INIS)

    Mesquita, R.N.; Libardi, R.M.P.; Masotti, P.H.F.; Sabundjian, G.; Andrade, D.A.; Umbehaun, P.E.; Torres, W.M.; Conti, T.N.; Macedo, L.A.

    2009-01-01

    Visualization of natural circulation test loop cycles is used to study two-phase flow patterns associated with phase transients and static instabilities of flow. Experimental studies on natural circulation flow were originally related to accidents and transient simulations relative to nuclear reactor systems with light water refrigeration. In this regime, fluid circulation is mainly caused by a driving force ('thermal head') which arises from density differences due to temperature gradient. Natural circulation phenomenon has been important to provide residual heat removal in cases of 'loss of pump power' or plant shutdown in nuclear power plant accidents. The new generation of compact nuclear reactors includes natural circulation of their refrigerant fluid as a security mechanism in their projects. Two-phase flow patterns have been studied for many decades, and the related instabilities have been object of special attention recently. Experimental facility is an all glass-made cylindrical tubes loop which contains about twelve demineralized water liters, a heat source by an electrical resistor immersion heater controlled by a Variac, and a helicoidal heat exchanger working as cold source. Data is obtained through thermo-pairs distributed over the loop and CCD cameras. Artificial intelligence based algorithms are used to improve (bubble) border detection and patterns recognition, in order to estimate and characterize, phase transitions patterns and correlate them with the periodic static instability (chugging) cycle observed in this circuit. Most of initial results show good agreement with previous numerical studies in this same facility. (author)

  18. Keynes's Lost Distinction Between Industrial and Financial Circulation of Money

    DEFF Research Database (Denmark)

    Jespersen, Jesper

    2010-01-01

    Although financial circulation is an important part of banks' balance sheets in the form of savings deposits, this is hardly discussed in monetary circuit theory. In this paper, we argue that monetary circuit theory would be more coherent if it were expanded to incorporate some aspects of Keynes...... in his Treatise on Money....

  19. 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.

  20. 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)

  1. Measurement of liquid level in a natural circulation circuit using an ultrasonic technique; Medição de nível de líquido em um circuito de circulação natural utilizando uma técnica ultrassônica

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Amanda Cardozo, E-mail: amandabarbosa@poli.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Departamento de Engenharia Nuclear; Faccini, José L.H., E-mail: faccini@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Su, Jian, E-mail: sujian@lasme.coppe.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2017-07-01

    The measurement by an ultrasonic technique of the water level in the expansion tank of the Natural Circulation Circuit (NCC) of the Experimental Thermo-Hydraulic Laboratory of the Institute of Nuclear Engineering is presented. In the single-phase NCC operation the water level in the expansion tank is stable. However, during the two-phase operation, oscillations occur in the water level due to temperature and vacuum fraction variations. Thus, the development of a technique that allows the measurement of these oscillations, will allow an estimation of the variation of the vacuum fraction of the circuit over time. The experimental set - up was performed on a test bench, using an ultrasonic transducer. The ultrasonic technique used is pulse-echo, in which the same transducer is the transmitter and receiver of the signal. The transducer-shoe assembly is part of an ultrasonic system consisting of an ultrasonic signal generating plate, transducers and a computer (PC) with a program in LabView to control the system. The program is able to calculate the transit time that the ultrasonic signals take to cross the tank base wall, the layer (level) of liquid and return to the transducer. Knowing the speed of the ultrasound in the wall and in the liquid it is possible to calculate the thickness of the wall and the height of the liquid. Measurements were made by filling the tank with a known volume of water and under varying temperature conditions, from room temperature to 90 deg C. The liquid heights are determined and the volume of water calculated by measuring the temperature with a digital thermometer. The volumes measured were highly accurate when compared to the known volumes.

  2. El Nino, from 1870 to 2014, and other Atmospheric Circulation Forcing by Extreme Apparitions of the Eight Annual, Continental Scale, Aerosol Plumes in the Satellite Era which Point to a Possible Cause for the Current Californian Drought

    Science.gov (United States)

    Potts, K. A.

    2015-12-01

    Eight continental scale aerosol plumes exist each year as the enclosed image shows. Apparitions of seven plumes only exist for a few months in the same season each year whilst the East Asian Plume is visible all year. The aerosol optical depth (AOD) of all the plumes varies enormously interannually with two studies showing the surface radiative forcing of the South East Asian Plume (SEAP) as -150W/m2 and -286W/m2/AOD. I show that the SEAP, created by volcanic aerosols (natural) and biomass burning and gas flares in the oil industry (anthropogenic), is the sole cause of all El Nino events, the greatest interannual perturbation of the atmospheric circulation system. The SEAP creates an El Nino by absorbing solar radiation at the top of the plume which heats the upper atmosphere and cools the surface. This creates a temperature inversion compared to periods without the plume and reduces convection. With reduced convection in SE Asia, the Maritime Continent, the Trade Winds blowing across the Pacific are forced to relax as their exit into the Hadley and Walker Cells is constrained and the reduced Trade Wind speed causes the Sea Surface Temperature (SST) to rise in the central tropical Pacific Ocean as there is a strong negative correlation between wind speed and SST. The warmer SST in the central Pacific creates convection in the region which further reduces the Trade Wind speed and causes the Walker Cell to reverse - a classic El Nino. Having established the ability of such extreme aerosol plumes to create El Nino events I will then show how the South American, West African, Middle East and SEAP plumes create drought in the Amazon, Spain, Darfur and Australia as well as causing the extremely warm autumn and winter in Europe in 2006-07. All these effects are created by the plumes reducing convection in the region of the plume which forces the regional Hadley Cells into anomalous positions thereby creating persistent high pressure cells in the mid latitudes. This

  3. Simple Cell Balance Circuit

    Science.gov (United States)

    Johnson, Steven D.; Byers, Jerry W.; Martin, James A.

    2012-01-01

    A method has been developed for continuous cell voltage balancing for rechargeable batteries (e.g. lithium ion batteries). A resistor divider chain is provided that generates a set of voltages representing the ideal cell voltage (the voltage of each cell should be as if the cells were perfectly balanced). An operational amplifier circuit with an added current buffer stage generates the ideal voltage with a very high degree of accuracy, using the concept of negative feedback. The ideal voltages are each connected to the corresponding cell through a current- limiting resistance. Over time, having the cell connected to the ideal voltage provides a balancing current that moves the cell voltage very close to that ideal level. In effect, it adjusts the current of each cell during charging, discharging, and standby periods to force the cell voltages to be equal to the ideal voltages generated by the resistor divider. The device also includes solid-state switches that disconnect the circuit from the battery so that it will not discharge the battery during storage. This solution requires relatively few parts and is, therefore, of lower cost and of increased reliability due to the fewer failure modes. Additionally, this design uses very little power. A preliminary model predicts a power usage of 0.18 W for an 8-cell battery. This approach is applicable to a wide range of battery capacities and voltages.

  4. Seasonal overturning circulation in the Red Sea: 2. Winter circulation

    KAUST Repository

    Yao, Fengchao

    2014-04-01

    The shallow winter overturning circulation in the Red Sea is studied using a 50 year high-resolution MITgcm (MIT general circulation model) simulation with realistic atmospheric forcing. The overturning circulation for a typical year, represented by 1980, and the climatological mean are analyzed using model output to delineate the three-dimensional structure and to investigate the underlying dynamical mechanisms. The horizontal model circulation in the winter of 1980 is dominated by energetic eddies. The climatological model mean results suggest that the surface inflow intensifies in a western boundary current in the southern Red Sea that switches to an eastern boundary current north of 24N. The overturning is accomplished through a cyclonic recirculation and a cross-basin overturning circulation in the northern Red Sea, with major sinking occurring along a narrow band of width about 20 km along the eastern boundary and weaker upwelling along the western boundary. The northward pressure gradient force, strong vertical mixing, and horizontal mixing near the boundary are the essential dynamical components in the model\\'s winter overturning circulation. The simulated water exchange is not hydraulically controlled in the Strait of Bab el Mandeb; instead, the exchange is limited by bottom and lateral boundary friction and, to a lesser extent, by interfacial friction due to the vertical viscosity at the interface between the inflow and the outflow. Key Points Sinking occurs in a narrow boundary layer along the eastern boundary Surface western boundary current switches into an eastern boundary current Water exchange in the Strait of Bab el Mandeb is not hydraulically controlled © 2014. American Geophysical Union. All Rights Reserved.

  5. 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

  6. 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

  7. 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.

  8. Research of Driving Circuit in Coaxial Induction Coilgun

    Directory of Open Access Journals (Sweden)

    Yadong Zhang

    2013-09-01

    Full Text Available Power supply is crucial equipment in coaxial induction coil launcher.Configuration of the driving circuit influences the efficiency of the coil launcher directly.This paper gives a detailed analysis of the properties of the driving circuit construction based on the capacitor source. Three topologies of the driving circuit are compared including oscillation circuit, crowbar circuit and half-wave circuit. It is proved that which circuit has the better efficiency depends on the detailed parameters of the experiment, especially the crowbar resistance. Crowbar resistor regulates not only efficiency of the system, but also temperature rise of the coil. Electromagnetic force (EMF applied on the armature will be another question which influences service condition of the driving circuits. Oscillation circuit and crowbar circuit should apply to the asynchronous induction coil launcher and synchronous induction coil launcher, respectively. Half-wave circuit is seldom used in the experiment. Although efficiency of the half-wave circuit is very high, the speed of the armature is low. A simple independent half-wave circuit is suggested in this paper. Generally speaking, the comprehensive property of crowbar circuit is the most practical in the three typical circuits. Conclusions of the paper could provide guidelines for practice.

  9. Nonreciprocal frequency conversion in a multimode microwave optomechanical circuit

    Science.gov (United States)

    Feofanov, A. K.; Bernier, N. R.; Toth, L. D.; Koottandavida, A.; Kippenberg, T. J.

    Nonreciprocal devices such as isolators, circulators, and directional amplifiers are pivotal to quantum signal processing with superconducting circuits. In the microwave domain, commercially available nonreciprocal devices are based on ferrite materials. They are barely compatible with superconducting quantum circuits, lossy, and cannot be integrated on chip. Significant potential exists for implementing non-magnetic chip-scale nonreciprocal devices using microwave optomechanical circuits. Here we demonstrate a possibility of nonreciprocal frequency conversion in a multimode microwave optomechanical circuit using solely optomechanical interaction between modes. The conversion scheme and the results reflecting the actual progress on the experimental implementation of the scheme will be presented.

  10. 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

  11. 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

  12. 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

  13. Automatic design of digital synthetic gene circuits.

    Directory of Open Access Journals (Sweden)

    Mario A Marchisio

    2011-02-01

    Full Text Available De novo computational design of synthetic gene circuits that achieve well-defined target functions is a hard task. Existing, brute-force approaches run optimization algorithms on the structure and on the kinetic parameter values of the network. However, more direct rational methods for automatic circuit design are lacking. Focusing on digital synthetic gene circuits, we developed a methodology and a corresponding tool for in silico automatic design. For a given truth table that specifies a circuit's input-output relations, our algorithm generates and ranks several possible circuit schemes without the need for any optimization. Logic behavior is reproduced by the action of regulatory factors and chemicals on the promoters and on the ribosome binding sites of biological Boolean gates. Simulations of circuits with up to four inputs show a faithful and unequivocal truth table representation, even under parametric perturbations and stochastic noise. A comparison with already implemented circuits, in addition, reveals the potential for simpler designs with the same function. Therefore, we expect the method to help both in devising new circuits and in simplifying existing solutions.

  14. 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)

  15. Seasonal Overturning Circulation in the Red Sea

    Science.gov (United States)

    Yao, F.; Hoteit, I.; Koehl, A.

    2010-12-01

    The Red Sea exhibits a distinct seasonal overturning circulation. In winter, a typical two-layer exchange structure, with a fresher inflow from the Gulf of Aden on top of an outflow from the Red Sea, is established. In summer months (June to September) this circulation pattern is changed to a three-layer structure: a surface outflow from the Red Sea on top of a subsurface intrusion of the Gulf of Aden Intermediate Water and a weakened deep outflow. This seasonal variability is studied using a general circulation model, MITgcm, with 6 hourly NCEP atmospheric forcing. The model is able to reproduce the observed seasonal variability very well. The forcing mechanisms of the seasonal variability related to seasonal surface wind stress and buoyancy flux, and water mass transformation processes associated with the seasonal overturning circulation are analyzed and presented.

  16. 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

  17. 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.

  18. 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...

  19. 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

  20. 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

  1. 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

  2. Modeling of Natural Self-Pressurized Circulation Circuits

    International Nuclear Information System (INIS)

    Zanocco, Pablo; Gimenez, Marcelo; Delmastro, Dario

    2003-01-01

    In this work, HUARPE code models for self-pressurized two-phase natural convection systems are improved.A drift-flux model is included, allowing the modeling of the relative velocity between phases.The model of steam dome structures is improved, with a thermal resistance scheme, in order to model the material thermal conductivity.This allows improving thermal losses modeling and structures dynamic.'Shape functions' are implemented based on analytic solutions for pressure derivative and density in each node, which allows less diffusive solving schemes, more appropriate for analyzing cases involving density waves phenomena.Finally, pressure evolutions during a pressurization transient are analyzed, comparing the new models and the previous version results.These results are also checked against RELAP code ones, obtained with different dome nodalizations. Moreover, modeling problems are analyzed for each case

  3. 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...

  4. Experimental study of the natural circulation phenomena

    International Nuclear Information System (INIS)

    Sabundjian, Gaiane; Andrade, Delvonei Alves de; Umbehaun, Pedro E.; Torres, Walmir M.; Castro, Alfredo Jose Alvim de; Belchior Junior, Antonio; Rocha, Ricardo Takeshi Vieira da; Damy, Osvaldo Luiz de Almeida; Torres, Eduardo

    2006-01-01

    The objective of this paper is to study the natural circulation in experimental loops and extend the results to nuclear facilities. New generation of compact nuclear power plants use the natural circulation as cooling and residual heat removal systems in case of accidents or shutdown. Lately the interest in this phenomenon, by scientific community, has increased. The experimental loop, described in this paper, was assembled at Escola Politecnica - USP at the Chemical Engineering Department. It is the goal to generate information to help with the understanding of the one and two phase natural circulation phenomena. Some experiments were performed with different levels of heat power and different flow of the cooling water at the secondary circuit. The data generated from these experiments are going to be used to validate some computational thermal hydraulic codes. Experimental results for one and two phase regimes are presented as well as the proposed model to simulate the flow regimes with the RELAP5 code. (author)

  5. The global atmospheric electric circuit and its effects on cloud microphysics

    International Nuclear Information System (INIS)

    Tinsley, B A

    2008-01-01

    circuit variations. The theory for electrical effects on scavenging of aerosols in clouds is reviewed, with several microphysical processes having consequences for contact ice nucleation; effects on droplet size distributions; precipitation and cloud lifetimes. There are several pathways for resulting macroscopic cloud changes that affect atmospheric circulation; including enhanced ice production and precipitation from clouds in cyclonic storms, with latent heat release affecting cyclone vorticity; and cloud cover changes in layer clouds that affect the atmospheric radiation balance. These macroscopic consequences of global circuit variability affecting aerosols-cloud interactions provide explanations for the many observations of short term and long term changes in clouds and climate that correlate with measured or inferred J z and cosmic ray flux changes due to external or internal forcing, and lead to predictions of additional effects

  6. The global atmospheric electric circuit and its effects on cloud microphysics

    Energy Technology Data Exchange (ETDEWEB)

    Tinsley, B A [Physics Department and Center for Space Sciences, WT15, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX, 75080-3021 (United States)], E-mail: Tinsley@UTDallas.edu

    2008-06-15

    inferred global circuit variations. The theory for electrical effects on scavenging of aerosols in clouds is reviewed, with several microphysical processes having consequences for contact ice nucleation; effects on droplet size distributions; precipitation and cloud lifetimes. There are several pathways for resulting macroscopic cloud changes that affect atmospheric circulation; including enhanced ice production and precipitation from clouds in cyclonic storms, with latent heat release affecting cyclone vorticity; and cloud cover changes in layer clouds that affect the atmospheric radiation balance. These macroscopic consequences of global circuit variability affecting aerosols-cloud interactions provide explanations for the many observations of short term and long term changes in clouds and climate that correlate with measured or inferred J{sub z} and cosmic ray flux changes due to external or internal forcing, and lead to predictions of additional effects.

  7. Josephson Circuits as Vector Quantum Spins

    Science.gov (United States)

    Samach, Gabriel; Kerman, Andrew J.

    While superconducting circuits based on Josephson junction technology can be engineered to represent spins in the quantum transverse-field Ising model, no circuit architecture to date has succeeded in emulating the vector quantum spin models of interest for next-generation quantum annealers and quantum simulators. Here, we present novel Josephson circuits which may provide these capabilities. We discuss our rigorous quantum-mechanical simulations of these circuits, as well as the larger architectures they may enable. This research was funded by the Office of the Director of National Intelligence (ODNI) and the Intelligence Advanced Research Projects Activity (IARPA) under Air Force Contract No. FA8721-05-C-0002. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of ODNI, IARPA, or the US Government.

  8. Quantum RLC circuits: Charge discreteness and resonance

    Energy Technology Data Exchange (ETDEWEB)

    Utreras-Diaz, Constantino A. [Instituto de Fisica, Facultad de Ciencias, Universidad Austral de Chile, Campus Isla Teja s/n, Casilla 567, Valdivia (Chile)], E-mail: cutreras@uach.cl

    2008-10-20

    In a recent article [C.A. Utreras-Diaz, Phys. Lett. A 372 (2008) 5059], we have advanced a semiclassical theory of quantum circuits with discrete charge and electrical resistance. In this work, we present a few elementary applications of this theory. For the zero resistance inductive circuit, we obtain the Stark ladder energies in yet another way; for the circuit driven by a combination d.c. plus a.c. electromotive force (emf) we generalize earlier results by Chandia et al. [K. Chandia, J.C. Flores, E. Lazo, Phys. Lett. A 359 (2006) 693]. As a second application, we investigate the effect of electrical resistance and charge discreteness, in the resonance conditions of a series RLC quantum circuit.

  9. Quantum RLC circuits: Charge discreteness and resonance

    International Nuclear Information System (INIS)

    Utreras-Diaz, Constantino A.

    2008-01-01

    In a recent article [C.A. Utreras-Diaz, Phys. Lett. A 372 (2008) 5059], we have advanced a semiclassical theory of quantum circuits with discrete charge and electrical resistance. In this work, we present a few elementary applications of this theory. For the zero resistance inductive circuit, we obtain the Stark ladder energies in yet another way; for the circuit driven by a combination d.c. plus a.c. electromotive force (emf) we generalize earlier results by Chandia et al. [K. Chandia, J.C. Flores, E. Lazo, Phys. Lett. A 359 (2006) 693]. As a second application, we investigate the effect of electrical resistance and charge discreteness, in the resonance conditions of a series RLC quantum circuit

  10. 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...

  11. [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.

  12. 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

  13. 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.

  14. 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. <

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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

  3. Opportunities in CARICOM Migration : Brain Circulation, Diasporic ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Opportunities in CARICOM Migration : Brain Circulation, Diasporic Tourism, and Investment. Between 1965 and 2000, about 12% of the Caribbean labour force moved to Canada and other developed countries, making the Caribbean the largest per capita source of emigrants in the world. Remittances from these emigrants ...

  4. 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...

  5. Microwave circulator design

    CERN Document Server

    Linkhart, Douglas K

    2014-01-01

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

  6. 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.

  7. Modelling of boiler heating surfaces and evaporator circuits

    DEFF Research Database (Denmark)

    Sørensen, K.; Condra, T.; Houbak, Niels

    2002-01-01

    the circulation in the evaporator circuit. The models have been developed as Differential-Algebraic-Equations (DAE) and MATLAB has been applied for the integration of the models. In general MATLAB has proved to be very stable for the relatively stiff equation systems. Experimental verification is planned...

  8. Natural Circulation Characteristics of an Integral Pressurized Water Reactor

    International Nuclear Information System (INIS)

    Junli Gou; Suizheng Qiu; Guanghui Su; Dounan Jia

    2006-01-01

    Natural circulation potential is of great importance to the inherent safety of a nuclear reactor. This paper presents a theoretical investigation on the natural circulation characteristics of an integrated pressurized water reactor. Through numerically solved the one-dimensional model, the steady-state single phase conservative equations for the primary circuit and the steady-state two-phase drift-flux conservative equations for the secondary side of the once-through steam generator, the natural circulation characteristics are studied. Based on the preliminary calculation analysis, it is found that natural circulation mass flow rate is proportional to the exponential function of the power, and the value of the exponent is related to working conditions of the steam generator secondary side. The higher height difference between the core center and the steam generator center is favorable to the heat removal capacity of the natural circulation. (authors)

  9. 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

  10. Thermalhydraulic instability analysis of a two phase natural circulation loop

    International Nuclear Information System (INIS)

    Sesini, Paula Aida

    1998-01-01

    This work presents an analysis of a loop operating in natural circulation regime. Experiments were done in a rectangular closed circuit in one and two-phase flows. Numerical analysis were performed initially with the CIRNAT code and afterwards with RELAP5/MOD2. The limitations of CIRNAT were studied and new developments for this code are proposed. (author)

  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. 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.

  14. 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

  15. 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

  16. 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

  17. 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.

  18. '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)

  19. Cascade of circulations in fluid turbulence.

    Science.gov (United States)

    Eyink, Gregory L

    2006-12-01

    Kelvin's theorem on conservation of circulations is an essential ingredient of Taylor's theory of turbulent energy dissipation by the process of vortex-line stretching. In previous work, we have proposed a nonlinear mechanism for the breakdown of Kelvin's theorem in ideal turbulence at infinite Reynolds number. We develop here a detailed physical theory of this cascade of circulations. Our analysis is based upon an effective equation for large-scale coarse-grained velocity, which contains a turbulent-induced vortex force that can violate Kelvin's theorem. We show that singularities of sufficient strength, which are observed to exist in turbulent flow, can lead to nonvanishing dissipation of circulation for an arbitrarily small coarse-graining length in the effective equations. This result is an analog for circulation of Onsager's theorem on energy dissipation for singular Euler solutions. The physical mechanism of the breakdown of Kelvin's theorem is diffusion of lines of large-scale vorticity out of the advected loop. This phenomenon can be viewed as a classical analog of the Josephson-Anderson phase-slip phenomenon in superfluids due to quantized vortex lines. We show that the circulation cascade is local in scale and use this locality to develop concrete expressions for the turbulent vortex force by a multiscale gradient expansion. We discuss implications for Taylor's theory of turbulent dissipation and we point out some related cascade phenomena, in particular for magnetic flux in magnetohydrodynamic turbulence.

  20. Simplifying the circuit of Josephson parametric converters

    Science.gov (United States)

    Abdo, Baleegh; Brink, Markus; Chavez-Garcia, Jose; Keefe, George

    Josephson parametric converters (JPCs) are quantum-limited three-wave mixing devices that can play various important roles in quantum information processing in the microwave domain, including amplification of quantum signals, transduction of quantum information, remote entanglement of qubits, nonreciprocal amplification, and circulation of signals. However, the input-output and biasing circuit of a state-of-the-art JPC consists of bulky components, i.e. two commercial off-chip broadband 180-degree hybrids, four phase-matched short coax cables, and one superconducting magnetic coil. Such bulky hardware significantly hinders the integration of JPCs in scalable quantum computing architectures. In my talk, I will present ideas on how to simplify the JPC circuit and show preliminary experimental results

  1. 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.

  2. 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.

  3. 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.

  4. On-Chip Microwave Quantum Hall Circulator

    Directory of Open Access Journals (Sweden)

    A. C. Mahoney

    2017-01-01

    Full Text Available Circulators are nonreciprocal circuit elements that are integral to technologies including radar systems, microwave communication transceivers, and the readout of quantum information devices. Their nonreciprocity arises from the interference of microwaves over the centimeter scale of the signal wavelength, in the presence of bulky magnetic media that breaks time-reversal symmetry. Here, we realize a completely passive on-chip microwave circulator with size 1/1000th the wavelength by exploiting the chiral, “slow-light” response of a two-dimensional electron gas in the quantum Hall regime. For an integrated GaAs device with 330  μm diameter and about 1-GHz center frequency, a nonreciprocity of 25 dB is observed over a 50-MHz bandwidth. Furthermore, the nonreciprocity can be dynamically tuned by varying the voltage at the port, an aspect that may enable reconfigurable passive routing of microwave signals on chip.

  5. Labour circulation and the urban labour process.

    Science.gov (United States)

    Standing, G

    1986-01-01

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

  6. 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

  7. 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…

  8. 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…

  9. Large-power microwave circuit device

    International Nuclear Information System (INIS)

    Suzuki, Kunio

    1987-01-01

    A 250 KW CW circulator and 1 MW CW dammy load are developed as large-power microwave circuit devices for Tristan, and they are shown to have good characteristics. The circulator has a Y-shape and consists of waveguides divided into four parts. Partition plates are provided in the waveguide connected to each port in order to divide the power into four components. A ferrite material which is high in Curie temperature and less likely to suffer from a RF loss is selected to be used in the circulator. Thin disks of this material, which is low in temperature gradient in the direction of thickness, are bonded to the surface of the waveguides with an epoxy adhesive. A magnet is provided at the top and bottom of the main portion of the circulator and the magnetic field is adjusted so that optimum characteristics are achieved. These arrangements result in good electrical and power characteristics. The dammy load of a water loading type is selected because microwave power is easily absorbed in water. A mechanically strong pipe which does not cause a large loss in microwave is mounted in a waveguide and water is passed through it to allow the power to be consumed gradually. A test up to a RF power of 750 KW shows that the temperature rise in the waveguide is 30 deg C. (Nogami, K.)

  10. Natural Circulation Characteristics of a Symmetric Loop under Inclined Conditions

    Directory of Open Access Journals (Sweden)

    Xingtuan Yang

    2014-01-01

    Full Text Available Natural circulation is an important process for primary loops of some marine integrated reactors. The reactor works under inclined conditions when severe accidents happen to the ship. In this paper, to investigate the characteristics of natural circulation, experiments were conducted in a symmetric loop under the inclined angle of 0~45°. A CFD model was also set up to predict the behaviors of the loop beyond the experimental scope. Total circulation flow rate decreases with the increase of inclined angle. Meanwhile one circulation is depressed while the other is enhanced, and accordingly the disparity between the branch circulations arises and increases with the increase of inclined angle. Circulation only takes place in one branch circuit at large inclined angle. Also based on the CFD model, the influences of flow resistance distribution and loop configuration on natural circulation are predicted. The numerical results show that to design the loop with the configuration of big altitude difference and small width, it is favorable to reduce the influence of inclination; however too small loop width will cause severe reduction of circulation ability at large angle inclination.

  11. 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.

  12. Duffing–van der Pol oscillator type dynamics in Murali–Lakshmanan–Chua (MLC) circuit

    International Nuclear Information System (INIS)

    Srinivasan, K.; Chandrasekar, V.K.; Venkatesan, A.; Raja Mohamed, I.

    2016-01-01

    Highlights: • Proposed an electronic circuit with diode based nonlinear element equivalent to a well known Murali–Lakshmanan–Chua (MLC) circuit. • For chosen circuit parameters this circuit admits familiar MLC type attractor and also Duffing–van der Pol circuit type chaotic attractor. • The performance of the circuit is investigated by means of explicit laboratory experiments, numerical simulations and analytical studies. - Abstract: We have constructed a simple second-order dissipative nonautonomous circuit exhibiting ordered and chaotic behaviour. This circuit is the well known Murali–Lakshmanan–Chua(MLC) circuit but with diode based nonlinear element. For chosen circuit parameters this circuit admits familiar MLC type attractor and also Duffing–van der Pol circuit type chaotic attractors. It is interesting to note that depending upon the circuit parameters the circuit shows both period doubling route to chaos and quasiperiodic route to chaos. In our study we have constructed two-parameter bifurcation diagrams in the forcing amplitude–frequency plane, one parameter bifurcation diagrams, Lyapunov exponents, 0–1 test and phase portrait. The performance of the circuit is investigated by means of laboratory experiments, numerical integration of appropriate mathematical model and explicit analytic studies.

  13. 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.)

  14. Twentieth century Walker Circulation change: data analysis and model experiments

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Qingjia [Leibniz-Institut fuer Meereswissenschaften, Kiel (Germany); Chinese Research Academy of Environmental Sciences, River and Coastal Environment Research Center, Beijing (China); Chinese Academy of Sciences, Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Qingdao (China); Latif, Mojib; Park, Wonsun; Keenlyside, Noel S.; Martin, Thomas [Leibniz-Institut fuer Meereswissenschaften, Kiel (Germany); Semenov, Vladimir A. [Leibniz-Institut fuer Meereswissenschaften, Kiel (Germany); A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow (Russian Federation)

    2012-05-15

    Recent studies indicate a weakening of the Walker Circulation during the twentieth century. Here, we present evidence from an atmospheric general circulation model (AGCM) forced by the history of observed sea surface temperature (SST) that the Walker Circulation may have intensified rather than weakened. Observed Equatorial Indo-Pacific Sector SST since 1870 exhibited a zonally asymmetric evolution: While the eastern part of the Equatorial Pacific showed only a weak warming, or even cooling in one SST dataset, the western part and the Equatorial Indian Ocean exhibited a rather strong warming. This has resulted in an increase of the SST gradient between the Maritime Continent and the eastern part of the Equatorial Pacific, one driving force of the Walker Circulation. The ensemble experiments with the AGCM, with and without time-varying external forcing, suggest that the enhancement of the SST gradient drove an anomalous atmospheric circulation, with an enhancement of both Walker and Hadley Circulation. Anomalously strong precipitation is simulated over the Indian Ocean and anomalously weak precipitation over the western Pacific, with corresponding changes in the surface wind pattern. Some sensitivity to the forcing SST, however, is noticed. The analysis of twentieth century integrations with global climate models driven with observed radiative forcing obtained from the Coupled Model Intercomparison Project (CMIP) database support the link between the SST gradient and Walker Circulation strength. Furthermore, control integrations with the CMIP models indicate the existence of strong internal variability on centennial timescales. The results suggest that a radiatively forced signal in the Walker Circulation during the twentieth century may have been too weak to be detectable. (orig.)

  15. 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

  16. 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.)

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. State of the Art Report for a Bearing for VHTR Helium Circulator

    International Nuclear Information System (INIS)

    Lee, Jae Seon; Song, Kee Nam; Kim, Yong Wan; Lee, Won Jae

    2008-10-01

    A helium circulator in a VHTR(Very High Temperature gas-cooled Reactor) plays a core role which translates thermal energy at high temperature from a nuclear core to a steam generator. Helium as a operating coolant circulates a primary circuit in high temperature and high pressure state, and controls thermal output of a nuclear core by controlling flow rate. A helium circulator is the only rotating machinery in a VHTR, and its reliability should be guaranteed for reliable operation of a reactor and stable production of hydrogen. Generally a main helium circulator is installed on the top of a steam generator vessel, and helium is circulated only by a main helium circulator in a normal operation state. An auxiliary or shutdown circulator is installed at the bottom of a reactor vessel, and it is an auxiliary circulator for shutting down a reactor in case of refueling or accelerating cooling down in case of fast cooling. Since a rotating shaft of a helium circulator is supported by bearings, bearings are the important machine elements which determines reliability of a helium circulator and a nuclear reactor. Various types of support bearings have been developed and applied for circulator bearings since 1960s, and it is still developing for developing VHTRs. So it is necessary to review and analyze the current technical state of helium circulator support bearings to develop bearings for Koran developing VHTR helium circulator

  4. Characteristic of onset of nucleate boiling in natural circulation

    International Nuclear Information System (INIS)

    Zhou Tao; Yang Ruichang; Liu Ruolei

    2006-01-01

    Two kinds of thermodynamics quality at onset of nucleate boiling with sub-cooled boiling were calculated for force circulation by using Bergles and Rohesenow method or Davis and Anderson method, and natural circulation by using Tsinghua University project group's empirical equations suggested in our natural circulation experiment at same condition. The characteristic of onset of nucleate boiling with subcooled boiling in natural circulation were pointed out. The research result indicates that the thermodynamics quality at onset of nucleate boiling with subcooled boiling in natural circulation is more sensitive for heat and inlet temperature and system pressure. Producing of onset of nucleate boiling with subcooled boiling is early at same condition. The research result also indicates more from microcosmic angle of statistical physics that the phenomena are caused by the effects of characteristic of dissipative structure of natural circulation in self organization, fluctuation force and momentum force of dynamics on thermodynamics equilibrium. these can lay good basis for study and application on sub-cooled boiling in natural circulation in future. (authors)

  5. Does the electromotive force (always represent work?

    Directory of Open Access Journals (Sweden)

    C. J. Papachristou

    2015-03-01

    Full Text Available In the literature of Electromagnetism, the electromotive force of a "circuit" is often defined as work done on a unit charge during a complete tour of the latter around the circuit. We explain why this statement cannot be generally regarded as true, although it is indeed true in certain simple cases. Several examples are used to illustrate these points.

  6. Sterilization of the artificial blood circulation apparatus with ozone

    Energy Technology Data Exchange (ETDEWEB)

    Pisarevskii, A A; Korukhov, N I.U.; Brazhnikov, E M; Konstantinova, M L; Razumovskii, S D

    1982-01-01

    Presented in this paper is the sterilization method of the assisted circulation unit. The method has been approved by stand testing and then applied for sterilizing the unit Ae, yeK-5 m when experimental implanting artificial heart. According to the method, ozone in concentration of 5 x 10(-3) moles/1 and with flow rate of 0,5 1/min is passed through an internal circuit of the unit during I h and 15 min. Control wash-out samples from lines have demonstrated complete sterility of the internal circuit. The method makes the sterilization process of such units much easier and may be recommended for clinical application.

  7. Double layers and circuits in astrophysics

    International Nuclear Information System (INIS)

    Alfven, H.

    1986-05-01

    As the rate of energy release in a double layer with voltage DeltaV is P corresponding to IDeltaV, a double layer must be treated part of a circuit which delivers the current I. As neither double layer nor circuit can be derived from magnetofluid models of a plasma, such models are useless for treating energy transfer by menas of double layers. They must be replaced by particle models and circuit theory. A simple circuit is suggested which is applied to the energizing of auroroal particles, to solar flares, and to intergalactic double radio sources. Application to the heliospheric current systems leads to the prediction of two double layers on the sun's axis which may give radiations detectable from earth. Double layers in space should be classified as a new type of celestial object (one example is the double radio sources). It is tentatively suggested in X-ray and gamma-ray bursts may be due to exploding double layers (although annihilation is an alternative energy source). A study of how a number of the most used textbooks in astrophysics treat important concepts like double layers, critical velocity, pinch effects and circuits is made. It is found that students using these textbooks remain essentially ignorant of even the existence of these, in spite of the fact that some of them have been well known for half a centry (e.g., double layers, Langmuir, 1929: pinch effect, Bennet, 1934). The conclusion is that astrophysics is too important to be left in the hands of the astrophysicist. Earth bound and space telescope data must be treated by scientists who are familiar with laboratory and magnetospheric physics and circuit theory, and of course with modern plasma theory. At least by volume the universe consists to more than 99 percent of plasma, and electromagnetic forces are 10/sup39/ time stronger than gravitation

  8. 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

  9. 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...

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. "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.

  16. 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

  17. 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

  18. 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

  19. 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)

  20. Nuclear reactor lid cooling which can work by natural circulation

    International Nuclear Information System (INIS)

    Wagner, J.

    1985-01-01

    The well-known air cooling of the lid of liquid metal cooled nuclear reactors is improved by the start of natural convection flow ensuring removal of heat in a sufficiently short time, if the blower fails. Go and return branches of the individual cooling circuits are arranged at different heights for this purpose. The circulation is supported by opening valves, which provide a direct path into the reactor building for the cooling air. The draught can be increased by setting up special chimneys. The start of circulation is aided by the temporary opening of another valve. (orig.) [de

  1. 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....

  2. 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)

  3. 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.

  4. 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

  5. Arctic circulation regimes.

    Science.gov (United States)

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

    2015-10-13

    Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability. © 2015 The Authors.

  6. Circulation and Directional Amplification in the Josephson Parametric Converter

    Science.gov (United States)

    Hatridge, Michael

    Nonreciprocal transport and directional amplification of weak microwave signals are fundamental ingredients in performing efficient measurements of quantum states of flying microwave light. This challenge has been partly met, as quantum-limited amplification is now regularly achieved with parametrically-driven, Josephson-junction based superconducting circuits. However, these devices are typically non-directional, requiring external circulators to separate incoming and outgoing signals. Recently this limitation has been overcome by several proposals and experimental realizations of both directional amplifiers and circulators based on interference between several parametric processes in a single device. This new class of multi-parametrically driven devices holds the promise of achieving a variety of desirable characteristics simultaneously- directionality, reduced gain-bandwidth constraints and quantum-limited added noise, and are good candidates for on-chip integration with other superconducting circuits such as qubits.

  7. 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...

  8. 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...

  9. 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.)

  10. 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

  11. 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

  12. 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.

  13. Space Time – Track Circuits with Trellis Code Modulation

    Directory of Open Access Journals (Sweden)

    Marius Enulescu

    2017-07-01

    Full Text Available The track circuits are very important equipments used in the railway transportation system. Today these are used to send vital information, to the running train, in the same time with the integrity checking of the rail. The actual track circuits have a small problem due to the use of the same transmission medium by the signals containing vital information and the return traction current, the running track rails. But this small problem can produce big disturbances in the train circulation, especially in the rush hours. To improve the data transmission to the train on-board equipment, the implementation of new track circuits using new communication technology were studied. This technology is used by the mobile and satellite communications and applies the principle of diversity encoding both time and space through the use of multiple transmission points of the track circuit signal for telegram which is sent to the train. Since this implementation does not satisfy the intended purpose, other modern communication principles such as 8PSK signals modulation and encoding using Trellis Coded Modulation were developed. This new track circuit aims to solve the problems which appeared in the current operation of track circuits and theoretically manages to transmit vital information to the train on board equipment without being affected by disturbances in electric traction transport systems.

  14. Fabrication of an electromagnetic pump with gas circulation

    International Nuclear Information System (INIS)

    Ravoire, J.

    1959-01-01

    This note reports the design and production of a pump aimed at circulating a gas in a closed circuit, and possessing some specific properties (tightness, gas in contact only with glass, operation pressure range, rates, resistance to overpressure). After a description of pump operation principle, the author describes the glassware part of the pump, its electromagnetic and electronic parts. He reports tests performed to assess pump characteristics. Obtained data are graphically presented, as well as a drawing of the pump

  15. Development of thermohydraulic software for PWR reactors with natural circulation

    International Nuclear Information System (INIS)

    Chasseur, Alfredo F.; Rauschert, A.; Delmastro, Dario F.

    2009-01-01

    The basics concepts about the development of software for steady state analysis of a reactor with natural circulations, in the primary circuit, are exposed. The reactor type is pressurized light water. The equations, correlations and flux diagrams of the source code of the software developed are shown. The source code of the software was written in FORTRAN 77 making use of modular technique, this save development effort and release of news versions is simplified. (author)

  16. 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

  17. 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.

  18. 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.)

  19. 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.

  20. 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

  1. Automated force controller for amplitude modulation atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Miyagi, Atsushi, E-mail: atsushi.miyagi@inserm.fr, E-mail: simon.scheuring@inserm.fr; Scheuring, Simon, E-mail: atsushi.miyagi@inserm.fr, E-mail: simon.scheuring@inserm.fr [U1006 INSERM, Université Aix-Marseille, Parc Scientifique et Technologique de Luminy, 163 Avenue de Luminy, 13009 Marseille (France)

    2016-05-15

    Atomic Force Microscopy (AFM) is widely used in physics, chemistry, and biology to analyze the topography of a sample at nanometer resolution. Controlling precisely the force applied by the AFM tip to the sample is a prerequisite for faithful and reproducible imaging. In amplitude modulation (oscillating) mode AFM, the applied force depends on the free and the setpoint amplitudes of the cantilever oscillation. Therefore, for keeping the applied force constant, not only the setpoint amplitude but also the free amplitude must be kept constant. While the AFM user defines the setpoint amplitude, the free amplitude is typically subject to uncontrollable drift, and hence, unfortunately, the real applied force is permanently drifting during an experiment. This is particularly harmful in biological sciences where increased force destroys the soft biological matter. Here, we have developed a strategy and an electronic circuit that analyzes permanently the free amplitude of oscillation and readjusts the excitation to maintain the free amplitude constant. As a consequence, the real applied force is permanently and automatically controlled with picoNewton precision. With this circuit associated to a high-speed AFM, we illustrate the power of the development through imaging over long-duration and at various forces. The development is applicable for all AFMs and will widen the applicability of AFM to a larger range of samples and to a larger range of (non-specialist) users. Furthermore, from controlled force imaging experiments, the interaction strength between biomolecules can be analyzed.

  2. 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.)

  3. An Oceanic General Circulation Model (OGCM) investigation of the Red Sea circulation: 2. Three-dimensional circulation in the Red Sea

    Science.gov (United States)

    Sofianos, Sarantis S.; Johns, William E.

    2003-03-01

    The three-dimensional circulation of the Red Sea is studied using a set of Miami Isopycnic Coordinate Ocean Model (MICOM) simulations. The model performance is tested against the few available observations in the basin and shows generally good agreement with the main observed features of the circulation. The main findings of this analysis include an intensification of the along-axis flow toward the coasts, with a transition from western intensified boundary flow in the south to eastern intensified flow in the north, and a series of strong seasonal or permanent eddy-like features. Model experiments conducted with different forcing fields (wind-stress forcing only, surface buoyancy forcing only, or both forcings combined) showed that the circulation produced by the buoyancy forcing is stronger overall and dominates the wind-driven part of the circulation. The main circulation pattern is related to the seasonal buoyancy flux (mostly due to the evaporation), which causes the density to increase northward in the basin and produces a northward surface pressure gradient associated with the downward sloping of the sea surface. The response of the eastern boundary to the associated mean cross-basin geostrophic current depends on the stratification and β-effect. In the northern part of the basin this results in an eastward intensification of the northward surface flow associated with the presence of Kelvin waves while in the south the traditional westward intensification due to Rossby waves takes place. The most prominent gyre circulation pattern occurs in the north where a permanent cyclonic gyre is present that is involved in the formation of Red Sea Outflow Water (RSOW). Beneath the surface boundary currents are similarly intensified southward undercurrents that carry the RSOW to the sill to flow out of the basin into the Indian Ocean.

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

    International Nuclear Information System (INIS)

    Wang, Dongqing; Jiang, Jin

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-01

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

  6. Nongeostrophic theory of zonally averaged circulation. I - Formulation

    Science.gov (United States)

    Tung, Ka Kit

    1986-01-01

    A nongeostrophic theory of zonally averaged circulation is formulated using the nonlinear primitive equations (mass conservation, thermodynamics, and zonal momentum) on a sphere. The relationship between the mean meridional circulation and diabatic heating rate is studied. Differences between results of nongeostropic theory and the geostrophic formulation concerning the role of eddy forcing of the diabatic circulation and the nonlinear nearly inviscid limit versus the geostrophic limit are discussed. Consideration is given to the Eliassen-Palm flux divergence, the Eliassen-Palm pseudodivergence, the nonacceleration theorem, and the nonlinear nongeostrophic Taylor relationship.

  7. Natural-circulation-cooling characteristics during PWR accident simulations

    International Nuclear Information System (INIS)

    Adams, J.P.; McCreery, G.E.; Berta, V.T.

    1983-01-01

    A description of natural circulation cooling characteristics is presented. Data were obtained from several pressurized water reactor accident simulations in the Loss-of-Fluid Test (LOFT) pressurized water reactor (PWR). The reliability of natural circulation cooling, its cooling effectiveness, and the effect of changing system conditions are described. Quantitative comparison of flow rates and time constants with theory for both single- and two-phase fluid conditions were made. It is concluded that natural circulation cooling can be relied on in plant recovery procedures in the absence of forced convection whenever the steam generator heat sink is available

  8. 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.

  9. Reliability analysis of 2400 MWth gas-cooled fast reactor natural circulation decay heat removal system

    International Nuclear Information System (INIS)

    Marques, M.; Bassi, C.; Bentivoglio, F.

    2012-01-01

    In support to a PSA (Probability Safety Assessment) performed at the design level on the 2400 MWth Gas-cooled Fast Reactor, the functional reliability of the decay heat removal system (DHR) working in natural circulation has been estimated in two transient situations corresponding to an 'aggravated' Loss of Flow Accident (LOFA) and a Loss of Coolant Accident (LOCA). The reliability analysis was based on the RMPS methodology. Reliability and global sensitivity analyses use uncertainty propagation by Monte Carlo techniques. The DHR system consists of 1) 3 dedicated DHR loops: the choice of 3 loops (3*100% redundancy) is made in assuming that one could be lost due to the accident initiating event (break for example) and that another one must be supposed unavailable (single failure criterion); 2) a metallic guard containment enclosing the primary system (referred as close containment), not pressurized in normal operation, having a free volume such as the fast primary helium expansion gives an equilibrium pressure of 1.0 MPa, in the first part of the transient (few hours). Each dedicated DHR loop designed to work in forced circulation with blowers or in natural circulation, is composed of 1) a primary loop (cross-duct connected to the core vessel), with a driving height of 10 meters between core and DHX mid-plan; 2) a secondary circuit filled with pressurized water at 1.0 MPa (driving height of 5 meters for natural circulation DHR); 3) a ternary pool, initially at 50 C. degrees, whose volume is determined to handle one day heat extraction (after this time delay, additional measures are foreseen to fill up the pool). The results obtained on the reliability of the DHR system and on the most important input parameters are very different from one scenario to the other showing the necessity for the PSA to perform specific reliability analysis of the passive system for each considered scenario. The analysis shows that the DHR system working in natural circulation is

  10. 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

  11. Power system with an integrated lubrication circuit

    Science.gov (United States)

    Hoff, Brian D [East Peoria, IL; Akasam, Sivaprasad [Peoria, IL; Algrain, Marcelo C [Peoria, IL; Johnson, Kris W [Washington, IL; Lane, William H [Chillicothe, IL

    2009-11-10

    A power system includes an engine having a first lubrication circuit and at least one auxiliary power unit having a second lubrication circuit. The first lubrication circuit is in fluid communication with the second lubrication circuit.

  12. Energy efficient circuit design using nanoelectromechanical relays

    Science.gov (United States)

    Venkatasubramanian, Ramakrishnan

    Nano-electromechanical (NEM) relays are a promising class of emerging devices that offer zero off-state leakage and behave like an ideal switch. Recent advances in planar fabrication technology have demonstrated that microelectromechanical (MEMS) scale miniature relays could be manufactured reliably and could be used to build fully functional, complex integrated circuits. The zero leakage operation of relays has renewed the interest in relay based low power logic design. This dissertation explores circuit architectures using NEM relays and NEMS-CMOS heterogeneous integration. Novel circuit topologies for sequential logic, memory, and power management circuits have been proposed taking into consideration the NEM relay device properties and optimizing for energy efficiency and area. In nanoscale electromechanical devices, dispersion forces like Van der Waals' force (vdW) affect the pull-in stability of the relay devices significantly. Verilog-A electromechanical model of the suspended gate relay operating at 1V with a nominal air gap of 5 - 10nm has been developed taking into account all the electrical, mechanical and dispersion effects. This dissertation explores different relay based latch and flip-flop topologies. It has been shown that as few as 4 relay cells could be used to build flip-flops. An integrated voltage doubler based flip flop that improves the performance by 2X by overdriving Vgb has been proposed. Three NEM relay based parallel readout memory bitcell architectures have been proposed that have faster access time, and remove the reliability issues associated with previously reported serial readout architectures. A paradigm shift in design of power switches using NEM relays is proposed. An interesting property of the relay device is that the ON state resistance (Ron) of the NEM relay switch is constant and is insensitive to the gate slew rate. This coupled with infinite OFF state resistance (Roff ) offers significant area and power advantages over CMOS

  13. Controlled humidity gas circulators

    International Nuclear Information System (INIS)

    Gruner, S.M.

    1981-01-01

    A programmable circulator capable of regulating the humidity of a gas stream over a wide range of humidity is described. An optical dew-point hygrometer is used as a feedback element to control the addition or removal of water vapor. Typical regulation of the gas is to a dew-point temperature of +- 0.2 0 C and to an accuracy limited by the dew-point hygrometer

  14. Fluid circulation control device

    International Nuclear Information System (INIS)

    Benard, Henri; Henocque, Jean.

    1982-01-01

    Horizontal fluid circulation control device, of the type having a pivoting flap. This device is intended for being fitted in the pipes of hydraulic installation, particularly in a bleed and venting system of a nuclear power station shifting radioactive or contaminated liquids. The characteristic of this device is the cut-out at the top of the flap to allow the air contained in the pipes to flow freely [fr

  15. Design and study of Engineering Test Facility - Helium Circulator

    International Nuclear Information System (INIS)

    Jiang Huijing; Ye Ping; Zhao Gang; Geng Yinan; Wang Jie

    2015-01-01

    Helium circulator is one of the key equipment of High-temperature Gas-cooled Reactor Pebble-bed Module (HTR-PM). In order to simulate most normal and accident operating conditions of helium circulator in HTR-PM, a full scale, rated flow rate and power, engineering test loop, which was called Engineering Test Facility - Helium Circulator (ETF-HC), was designed and established. Two prototypes of helium circulator, which was supported by Active Magnetic Bearing (AMB) or sealed by dry gas seals, would be tested on ETF-HC. Therefore, special interchangeable design was under consideration. ETF-HC was constructed compactly, which consisted of eleven sub-systems. In order to reduce the flow resistance of the circuit, special ducts, elbows, valves and flowmeters were selected. Two stages of heat exchange loops were designed and a helium - high pressure pure water heat exchanger was applied to ensure water wouldn't be vaporized while simulating accident conditions. Commissioning tests were carried out and operation results showed that ETF-HC meets the requirement of helium circulator operation. On this test facility, different kinds of experiments were supposed to be held, including mechanical and aerodynamic performance tests, durability tests and so on. These tests would provide the features and performance of helium circulator and verify its feasibility, availability and reliability. (author)

  16. A Coordinate Control Strategy for Circulating Current Suppression in Multiparalleled Three-Phase Inverters

    DEFF Research Database (Denmark)

    Zhang, Xueguang; Wang, Tianyi; Wang, Xiongfei

    2017-01-01

    This paper addresses the zero-sequence circulating current control in the multiparalleled three-phase voltage-source inverters. The model of the zero-sequence circulating current in the N-paralleled (N ≥ 3) inverters is derived. It is shown that the circulating current is not only susceptible...... to the mismatches of circuit parameters, but it is also influenced by the interactions of circulating current controllers used by other paralleled inverters. To eliminate these adverse effects on the circulating current control loop, a coordinate control strategy for the N-paralleled inverter is proposed based...... on the zero-vector feedforward method with the space-vector pulse width modulation. Moreover, a virtual inverter method is introduced to facilitate the implementation of the proposed controller, which decouples the interactions of circulating current controllers in the paralleled inverters. Finally...

  17. 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)

  18. Subatomic forces

    International Nuclear Information System (INIS)

    Sutton, C.

    1989-01-01

    Inside the atom, particles interact through two forces which are never felt in the everyday world. But they may hold the key to the Universe. These ideas on subatomic forces are discussed with respect to the strong force, the electromagnetic force and the electroweak force. (author)

  19. Characterization of natural circulation looping of emergency cooling systems in naval and advanced reactors

    International Nuclear Information System (INIS)

    Macedo, Luiz Alberto; Baptista Filho, Benedito Dias

    2000-01-01

    This paper describes the natural circuit looping, resumes the main project characteristics, presents results of the hydraulic characterization, consisting of pressure loss measurements, and presents results from calibration tests of the power and flow measurements and the first experiments in natural circulation. Those experiments comprised transients in natural circulation with application of application of power steps. The results shown a non linear behaviour of the magnetic flow meter and a dependence on the fluid temperature as well. The assembly circuit/instrumentation/data acquisition system is suitable for the research on emergency cooling passive systems

  20. 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.)

  1. Fuel Cooling in Absence of Forced Flow at Shutdown Condition with PHTS Partially Drained

    Energy Technology Data Exchange (ETDEWEB)

    Parasca, L.; Pecheanu, D.L., E-mail: laurentiu.parasca@cne.ro, E-mail: doru.pecheanu@cne.ro [Cernavoda Nuclear Power Plant, Cernavoda (Romania)

    2014-09-15

    During the plant outage for maintenance on primary side (e.g. for the main Heat Transport System pumps maintenance, the Steam Generators inspection), there are situations which require the primary heat transport system (HTS) drainage to a certain level for opening the circuit. The primary fuel heat sink for this configuration is provided by the shutdown cooling system (SDCS). In case of losing the forced cooling (e.g. due to the loss of SDCS, design basis earthquake-DBE), flow conditions in the reactor core may become stagnant. Inside the fuel channels, natural circulation phenomena known as Intermittent Buoyancy Induced Flow (IBIF) will initiate, providing an alternate heat sink mechanism for the fuel. However, this heat sink is effective only for a limited period of time (recall time). The recall time is defined as the elapsed time until the water temperature in the HTS headers exceeds a certain limit. Until then, compensatory measures need to be taken (e.g. by re-establishing the forced flow or initiate Emergency Core Cooling system injection) to preclude fuel failures. The present paper briefly presents the results of an analysis performed to demonstrate that fuel temperature remains within acceptable limits during IBIF transient. One of the objectives of this analysis was to determine the earliest moment since the reactor shut down when maintenance activities on the HTS can be started such that IBIF is effective in case of losing the forced circulation. The resulting peak fuel sheath and pressure tube temperatures due to fuel heat up shall be within the acceptable limits to preclude fuel defect or fuel channel defects.Thermalhydraulic circuit conditions were obtained using a CATHENA model for the primary side of HTS (drained to a certain level), an ECC system model and a system model for SDCS. A single channel model was developed in GOTHIC code for the fuel assessment analysis. (author)

  2. The stability of the thermohaline circulation in a coupled ocean-atmosphere general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Schiller, A. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Mikolajewicz, U. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Voss, R. [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany)

    1996-02-01

    The stability of the Atlantic thermohaline circulation against meltwater input is investigated in a coupled ocean-atmosphere general circulation model. The meltwater input to the Labrador Sea is increased linearly for 250 years to a maximum input of 0.625 Sv and then reduced again to 0 (both instantaneously and slowly decreasing over 250 years). The resulting freshening forces a shutdown of the formation of North Atlantic deepwater and a subsequent reversal of the thermohaline circulation of the Atlantic, filling the deep Atlantic with Antarctic bottom water. The change in the overturning pattern causes a drastic reduction of the Atlantic northward heat transport, resulting in a strong cooling with maximum amplitude over the northern North Atlantic and a southward shift of the sea-ice margin in the Atlantic. Due to the increased meridional temperature gradient, the Atlantic intertropical convergence zone is displaced southward and the westerlies in the northern hemisphere gain strength. We identify four main feedbacks affecting the stability of the thermohaline circulation: the change in the overturning circulation of the Atlantic leads to longer residence times of the surface waters in high northern latitudes, which allows them to accumulate more precipitation and runoff from the continents, which results in an increased stability in the North Atlantic.

  3. Seasonal overturning circulation in the Red Sea: 1. Model validation and summer circulation

    KAUST Repository

    Yao, Fengchao

    2014-04-01

    The overturning circulation in the Red Sea exhibits a distinct seasonally reversing pattern and is studied using high-resolution MIT general circulation model simulations. In the first part of this study, the vertical and horizontal structure of the summer overturning circulation and its dynamical mechanisms are presented from the model results. The seasonal water exchange in the Strait of Bab el Mandeb is successfully simulated, and the structures of the intruding subsurface Gulf of Aden intermediate water are in good agreement with summer observations in 2011. The model results suggest that the summer overturning circulation is driven by the combined effect of the shoaling of the thermocline in the Gulf of Aden resulting from remote winds in the Arabian Sea and an upward surface slope from the Red Sea to the Gulf of Aden set up by local surface winds in the Red Sea. In addition, during late summer two processes associated, respectively, with latitudinally differential heating and increased salinity in the southern Red Sea act together to cause the reversal of the contrast of the vertical density structure and the cessation of the summer overturning circulation. Dynamically, the subsurface northward pressure gradient force is mainly balanced by vertical viscosity resulting from the vertical shear and boundary friction in the Strait of Bab el Mandeb. Unlike some previous studies, the three-layer summer exchange flows in the Strait of Bab el Mandeb do not appear to be hydraulically controlled.

  4. Seasonal overturning circulation in the Red Sea: 1. Model validation and summer circulation

    KAUST Repository

    Yao, Fengchao; Hoteit, Ibrahim; Pratt, Larry J.; Bower, Amy S.; Zhai, Ping; Kö hl, Armin; Gopalakrishnan, Ganesh

    2014-01-01

    The overturning circulation in the Red Sea exhibits a distinct seasonally reversing pattern and is studied using high-resolution MIT general circulation model simulations. In the first part of this study, the vertical and horizontal structure of the summer overturning circulation and its dynamical mechanisms are presented from the model results. The seasonal water exchange in the Strait of Bab el Mandeb is successfully simulated, and the structures of the intruding subsurface Gulf of Aden intermediate water are in good agreement with summer observations in 2011. The model results suggest that the summer overturning circulation is driven by the combined effect of the shoaling of the thermocline in the Gulf of Aden resulting from remote winds in the Arabian Sea and an upward surface slope from the Red Sea to the Gulf of Aden set up by local surface winds in the Red Sea. In addition, during late summer two processes associated, respectively, with latitudinally differential heating and increased salinity in the southern Red Sea act together to cause the reversal of the contrast of the vertical density structure and the cessation of the summer overturning circulation. Dynamically, the subsurface northward pressure gradient force is mainly balanced by vertical viscosity resulting from the vertical shear and boundary friction in the Strait of Bab el Mandeb. Unlike some previous studies, the three-layer summer exchange flows in the Strait of Bab el Mandeb do not appear to be hydraulically controlled.

  5. Dynamic pulse difference circuit

    International Nuclear Information System (INIS)

    Erickson, G.L.

    1978-01-01

    A digital electronic circuit of especial use for subtracting background activity pulses in gamma spectrometry is disclosed which comprises an up-down counter connected to count up with signal-channel pulses and to count down with background-channel pulses. A detector responsive to the count position of the up-down counter provides a signal when the up-down counter has completed one scaling sequence cycle of counts in the up direction. In an alternate embodiment, a detector responsive to the count position of the up-down counter provides a signal upon overflow of the counter

  6. Electronics circuits and systems

    CERN Document Server

    Bishop, Owen

    2007-01-01

    The material in Electronics - Circuits and Systems is a truly up-to-date textbook, with coverage carefully matched to the electronics units of the 2007 BTEC National Engineering and the latest AS and A Level specifications in Electronics from AQA, OCR and WJEC. The material has been organized with a logical learning progression, making it ideal for a wide range of pre-degree courses in electronics. The approach is student-centred and includes: numerous examples and activities; web research topics; Self Test features, highlighted key facts, formulae and definitions. Each chapter ends with a set

  7. Electric circuits problem solver

    CERN Document Server

    REA, Editors of

    2012-01-01

    Each Problem Solver is an insightful and essential study and solution guide chock-full of clear, concise problem-solving gems. All your questions can be found in one convenient source from one of the most trusted names in reference solution guides. More useful, more practical, and more informative, these study aids are the best review books and textbook companions available. Nothing remotely as comprehensive or as helpful exists in their subject anywhere. Perfect for undergraduate and graduate studies.Here in this highly useful reference is the finest overview of electric circuits currently av

  8. Digital logic circuit test

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Gil Jung; Yang, Hong Young

    2011-03-15

    This book is about digital logic circuit test, which lists the digital basic theory, basic gate like and, or And Not gate, NAND/NOR gate such as NAND gate, NOR gate, AND and OR, logic function, EX-OR gate, adder and subtractor, decoder and encoder, multiplexer, demultiplexer, flip-flop, counter such as up/down counter modulus N counter and Reset type counter, shift register, D/A and A/D converter and two supplements list of using components and TTL manual and CMOS manual.

  9. Photonic Integrated Circuits

    Science.gov (United States)

    Krainak, Michael; Merritt, Scott

    2016-01-01

    Integrated photonics generally is the integration of multiple lithographically defined photonic and electronic components and devices (e.g. lasers, detectors, waveguides passive structures, modulators, electronic control and optical interconnects) on a single platform with nanometer-scale feature sizes. The development of photonic integrated circuits permits size, weight, power and cost reductions for spacecraft microprocessors, optical communication, processor buses, advanced data processing, and integrated optic science instrument optical systems, subsystems and components. This is particularly critical for small spacecraft platforms. We will give an overview of some NASA applications for integrated photonics.

  10. Integrated circuit cell library

    Science.gov (United States)

    Whitaker, Sterling R. (Inventor); Miles, Lowell H. (Inventor)

    2005-01-01

    According to the invention, an ASIC cell library for use in creation of custom integrated circuits is disclosed. The ASIC cell library includes some first cells and some second cells. Each of the second cells includes two or more kernel cells. The ASIC cell library is at least 5% comprised of second cells. In various embodiments, the ASIC cell library could be 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more comprised of second cells.

  11. 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.

  12. Electronic logic circuits

    CERN Document Server

    Gibson, J

    2013-01-01

    Most branches of organizing utilize digital electronic systems. This book introduces the design of such systems using basic logic elements as the components. The material is presented in a straightforward manner suitable for students of electronic engineering and computer science. The book is also of use to engineers in related disciplines who require a clear introduction to logic circuits. This third edition has been revised to encompass the most recent advances in technology as well as the latest trends in components and notation. It includes a wide coverage of application specific integrate

  13. Linear integrated circuits

    CERN Document Server

    Carr, Joseph

    1996-01-01

    The linear IC market is large and growing, as is the demand for well trained technicians and engineers who understand how these devices work and how to apply them. Linear Integrated Circuits provides in-depth coverage of the devices and their operation, but not at the expense of practical applications in which linear devices figure prominently. This book is written for a wide readership from FE and first degree students, to hobbyists and professionals.Chapter 1 offers a general introduction that will provide students with the foundations of linear IC technology. From chapter 2 onwa

  14. 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.

  15. Electronics circuits and systems

    CERN Document Server

    Bishop, Owen

    2011-01-01

    The material in Electronics - Circuits and Systems is a truly up-to-date textbook, with coverage carefully matched to the electronics units of the 2007 BTEC National Engineering and the latest AS and A Level specifications in Electronics from AQA, OCR and WJEC. The material has been organized with a logical learning progression, making it ideal for a wide range of pre-degree courses in electronics. The approach is student-centred and includes: numerous examples and activities; web research topics; Self Test features, highlighted key facts, formulae and definitions. Ea

  16. Optoelectronics circuits manual

    CERN Document Server

    Marston, R M

    1999-01-01

    This manual is a useful single-volume guide specifically aimed at the practical design engineer, technician, and experimenter, as well as the electronics student and amateur. It deals with the subject in an easy to read, down to earth, and non-mathematical yet comprehensive manner, explaining the basic principles and characteristics of the best known devices, and presenting the reader with many practical applications and over 200 circuits. Most of the ICs and other devices used are inexpensive and readily available types, with universally recognised type numbers.The second edition

  17. Optically controllable molecular logic circuits

    International Nuclear Information System (INIS)

    Nishimura, Takahiro; Fujii, Ryo; Ogura, Yusuke; Tanida, Jun

    2015-01-01

    Molecular logic circuits represent a promising technology for observation and manipulation of biological systems at the molecular level. However, the implementation of molecular logic circuits for temporal and programmable operation remains challenging. In this paper, we demonstrate an optically controllable logic circuit that uses fluorescence resonance energy transfer (FRET) for signaling. The FRET-based signaling process is modulated by both molecular and optical inputs. Based on the distance dependence of FRET, the FRET pathways required to execute molecular logic operations are formed on a DNA nanostructure as a circuit based on its molecular inputs. In addition, the FRET pathways on the DNA nanostructure are controlled optically, using photoswitching fluorescent molecules to instruct the execution of the desired operation and the related timings. The behavior of the circuit can thus be controlled using external optical signals. As an example, a molecular logic circuit capable of executing two different logic operations was studied. The circuit contains functional DNAs and a DNA scaffold to construct two FRET routes for executing Input 1 AND Input 2 and Input 1 AND NOT Input 3 operations on molecular inputs. The circuit produced the correct outputs with all possible combinations of the inputs by following the light signals. Moreover, the operation execution timings were controlled based on light irradiation and the circuit responded to time-dependent inputs. The experimental results demonstrate that the circuit changes the output for the required operations following the input of temporal light signals

  18. Sequential circuit design for radiation hardened multiple voltage integrated circuits

    Science.gov (United States)

    Clark, Lawrence T [Phoenix, AZ; McIver, III, John K.

    2009-11-24

    The present invention includes a radiation hardened sequential circuit, such as a bistable circuit, flip-flop or other suitable design that presents substantial immunity to ionizing radiation while simultaneously maintaining a low operating voltage. In one embodiment, the circuit includes a plurality of logic elements that operate on relatively low voltage, and a master and slave latches each having storage elements that operate on a relatively high voltage.

  19. Advanced Breakdown Modeling for Solid-State Circuit Design

    NARCIS (Netherlands)

    Milovanovi?, V.

    2010-01-01

    Modeling of the effects occurring outside the usual region of application of semiconductor devices is becoming more important with increasing demands set upon electronic systems for simultaneous speed and output power. Analog integrated circuit designers are forced to enter regimes of transistor

  20. Quantum-Circuit Refrigerator

    Science.gov (United States)

    MöTtöNen, Mikko; Tan, Kuan Y.; Masuda, Shumpei; Partanen, Matti; Lake, Russell E.; Govenius, Joonas; Silveri, Matti; Grabert, Hermann

    Quantum technology holds great potential in providing revolutionizing practical applications. However, fast and precise cooling of the functional quantum degrees of freedom on demand remains a major challenge in many solid-state implementations, such as superconducting circuits. We demonstrate direct cooling of a superconducting resonator mode using voltage-controllable quantum tunneling of electrons in a nanoscale refrigerator. In our first experiments on this type of a quantum-circuit refrigerator, we measure the drop in the mode temperature by electron thermometry at a resistor which is coupled to the resonator mode through ohmic losses. To eliminate unwanted dissipation, we remove the probe resistor and directly observe the power spectrum of the resonator output in agreement with the so-called P(E) theory. We also demonstrate in microwave reflection experiments that the internal quality factor of the resonator can be tuned by orders of magnitude. In the future, our refrigerator can be integrated with different quantum electric devices, potentially enhancing their performance. For example, it may prove useful in the initialization of superconducting quantum bits and in dissipation-assisted quantum annealing. We acknowledge European Research Council Grant SINGLEOUT (278117) and QUESS (681311) for funding.

  1. Quasi-Linear Circuit

    Science.gov (United States)

    Bradley, William; Bird, Ross; Eldred, Dennis; Zook, Jon; Knowles, Gareth

    2013-01-01

    This work involved developing spacequalifiable switch mode DC/DC power supplies that improve performance with fewer components, and result in elimination of digital components and reduction in magnetics. This design is for missions where systems may be operating under extreme conditions, especially at elevated temperature levels from 200 to 300 degC. Prior art for radiation-tolerant DC/DC converters has been accomplished utilizing classical magnetic-based switch mode converter topologies; however, this requires specific shielding and component de-rating to meet the high-reliability specifications. It requires complex measurement and feedback components, and will not enable automatic re-optimization for larger changes in voltage supply or electrical loading condition. The innovation is a switch mode DC/DC power supply that eliminates the need for processors and most magnetics. It can provide a well-regulated voltage supply with a gain of 1:100 step-up to 8:1 step down, tolerating an up to 30% fluctuation of the voltage supply parameters. The circuit incorporates a ceramic core transformer in a manner that enables it to provide a well-regulated voltage output without use of any processor components or magnetic transformers. The circuit adjusts its internal parameters to re-optimize its performance for changes in supply voltage, environmental conditions, or electrical loading at the output

  2. Moderator circulation in CANDU reactors

    International Nuclear Information System (INIS)

    Fath, H.E.S.; Hussein, M.A.

    1989-01-01

    A two-dimensional computer code that is capable of predicting the moderator flow and temperature distribution inside CANDU calandria is presented. The code uses a new approach to simulate the calandria tube matrix by blocking the cells containing the tubes in the finite difference mesh. A jet momentum-dominant flow pattern is predicted in the nonisothermal case, and the effect of the buoyancy force, resulting from nuclear heating, is found to enhance the speed of circulation. Hot spots are located in low-velocity areas at the top of the calandria and below the inlet jet level between the fuel channels. A parametric study is carried out to investigate the effect of moderator inlet velocity,moderator inlet nozzle location, and geometric scaling. The results indicate that decreasing the moderator inlet velocity has no significant influence on the general features of the flow pattern (i.e., momentum dominant); however, too many high-temperature hot spots appear within the fuel channels

  3. 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 ...

  4. Integrated circuit cooled turbine blade

    Science.gov (United States)

    Lee, Ching-Pang; Jiang, Nan; Um, Jae Y.; Holloman, Harry; Koester, Steven

    2017-08-29

    A turbine rotor blade includes at least two integrated cooling circuits that are formed within the blade that include a leading edge circuit having a first cavity and a second cavity and a trailing edge circuit that includes at least a third cavity located aft of the second cavity. The trailing edge circuit flows aft with at least two substantially 180-degree turns at the tip end and the root end of the blade providing at least a penultimate cavity and a last cavity. The last cavity is located along a trailing edge of the blade. A tip axial cooling channel connects to the first cavity of the leading edge circuit and the penultimate cavity of the trailing edge circuit. At least one crossover hole connects the penultimate cavity to the last cavity substantially near the tip end of the blade.

  5. Control circuit for transformer relay

    International Nuclear Information System (INIS)

    Wyatt, G.A.

    1984-01-01

    A control circuit for a transformer relay which will automatically momentarily control the transformer relay to a selected state upon energization of the control circuit. The control circuit has an energy storage element and a current director coupled in series and adapted to be coupled with the secondary winding of the transformer relay. A device for discharge is coupled across the energy storage element. The energy storage element and current director will momentarily allow a unidirectional flow of current in the secondary winding of the transformer relay upon application of energy to the control circuit. When energy is not applied to the control circuit the device for discharge will allow the energy storage element to discharge and be available for another operation of the control circuit

  6. Circulating current battery heater

    Science.gov (United States)

    Ashtiani, Cyrus N.; Stuart, Thomas A.

    2001-01-01

    A circuit for heating energy storage devices such as batteries is provided. The circuit includes a pair of switches connected in a half-bridge configuration. Unidirectional current conduction devices are connected in parallel with each switch. A series resonant element for storing energy is connected from the energy storage device to the pair of switches. An energy storage device for intermediate storage of energy is connected in a loop with the series resonant element and one of the switches. The energy storage device which is being heated is connected in a loop with the series resonant element and the other switch. Energy from the heated energy storage device is transferred to the switched network and then recirculated back to the battery. The flow of energy through the battery causes internal power dissipation due to electrical to chemical conversion inefficiencies. The dissipated power causes the internal temperature of the battery to increase. Higher internal temperatures expand the cold temperature operating range and energy capacity utilization of the battery. As disclosed, either fixed frequency or variable frequency modulation schemes may be used to control the network.

  7. Source-circuit design overview

    Science.gov (United States)

    Ross, R. G., Jr.

    1983-01-01

    The source circuit is the fundamental electrical building block of a large central-station array; it consists of a series-parallel network of solar cells that develops full system voltage. The array field is generally made up of a large number of parallel source circuits. Source-circuit electrical configuration is driven by a number of design considerations, which must be considered simultaneously. Array fault tolerance and hot spot heating endurance are examined in detail.

  8. Design and fabrication of a micro fluidic circuit for the separation of micron sized particles

    CSIR Research Space (South Africa)

    Khumalo, F

    2009-07-01

    Full Text Available The development of a micro fluidic circuit for the separation of micro particles is being investigated. There are a wide range of available separation techniques such as acoustic, laminar flow, split flow, optical trapping and centrifugal forces...

  9. Determination of short circuit stresses in an air core reactor using ...

    African Journals Online (AJOL)

    DR OKE

    developed has crossed the boundary condition limit of 70 MPa whereas the ... The method can be used to identify the inter layer forces ... Power transformer design using magnetic circuit theory and finite element analysis – A Comparison.

  10. Experimental investigation of an active magnetic regenerative heat circulator applied to self-heat recuperation technology

    International Nuclear Information System (INIS)

    Kotani, Yui; Kansha, Yasuki; Ishizuka, Masanori; Tsutsumi, Atsushi

    2014-01-01

    An experimental investigation into an active magnetic regenerative (AMR) heat circulator based on self-heat recuperation technology, was conducted to evaluate its energy saving potential in heat circulation. In an AMR heat circulator, magnetocaloric effect is applied to recuperate the heat exergy of the process fluid. The recuperated heat can be reused to heat the feed process fluid and realize self-heat recuperation. In this paper, AMR heat circulator has newly been constructed to determine the amount of heat circulated when applied to self-heat recuperation and the energy consumption of the heat circulator. Gadolinium and water was used as the magnetocaloric working material and the process fluid, respectively. The heat circulated amount was determined by measuring the temperature of the process fluid and gadolinium. The net work input for heat circulation was obtained from the magnetizing and demagnetizing forces and the distance travelled by the magnetocaloric bed. The results were compared with the minimum work input needed for heat circulation derived from exergy loss during heat exchange. It was seen that the experimentally obtained value was close to the minimum work input needed for heat circulation. - Highlights: • AMR heat circulator has newly been constructed for experimental evaluation. • Heat circulation in the vicinity of Curie temperature was observed. • Energy consumption of an AMR heat circulator has been measured. • Energy saving for processes near Curie temperature of working material was seen

  11. Radiation-sensitive switching circuits

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.H.; Cockshott, C.P.

    1976-03-16

    A radiation-sensitive switching circuit has a light emitting diode which supplies light to a photo-transistor, the light being interrupted from time to time. When the photo-transistor is illuminated, current builds up and when this current reaches a predetermined value, a trigger circuit changes state. The peak output of the photo-transistor is measured and the trigger circuit is arranged to change state when the output of the device is a set proportion of the peak output, so as to allow for aging of the components. The circuit is designed to control the ignition system in an automobile engine.

  12. Four-junction superconducting circuit

    Science.gov (United States)

    Qiu, Yueyin; Xiong, Wei; He, Xiao-Ling; Li, Tie-Fu; You, J. Q.

    2016-01-01

    We develop a theory for the quantum circuit consisting of a superconducting loop interrupted by four Josephson junctions and pierced by a magnetic flux (either static or time-dependent). In addition to the similarity with the typical three-junction flux qubit in the double-well regime, we demonstrate the difference of the four-junction circuit from its three-junction analogue, including its advantages over the latter. Moreover, the four-junction circuit in the single-well regime is also investigated. Our theory provides a tool to explore the physical properties of this four-junction superconducting circuit. PMID:27356619

  13. Radiology of liver circulation

    International Nuclear Information System (INIS)

    Hermine, C.L.

    1985-01-01

    This book proposes that careful evaluation of the arterioportogram is the cornerstone in assessing portal flow obstruction, being the most consistent of all observations including liver histology, portal venous pressure, size and number of portosystemic collaterals, and wedged hepatic venous pressure. Very brief chapters cover normal hepatic circulation and angiographic methods. Contrast volumes and flow rates for celiac, hepatic, and superior mesenteric injection are given, with the timing for venous phase radiographs. In the main body of the text, portal obstruction is divided very simply into presinusoidal (all proximal causes) and postsinusoidal (all distal causes, including Budd-Chiari). Changes are discussed regarding the splenic artery and spleen; hepatic artery and its branches; portal flow rate and direction; and arterioportal shunting and portosystemic collateral circulation in minimal, moderate, severe, and very severe portal obstruction and in recognizable entities such as prehepatic portal and hepatic venous obstructions. The major emphasis in this section is the recognition and understanding of flow changes by which level and severity of obstruction are assessed (not simply the anatomy of portosystemic collateral venous flow). Excellent final chapters discuss the question of portal hypertension without obstruction, and the contribution of arterioportography to the treatment of portal hypertension, again with an emphasis on hemodynamics before and after shunt surgery. There is a fascinating final chapter on segmental intrahepatic obstruction without portal hypertension that explains much of the unusual contrast enhancement sometimes seen in CT scanning of hepatic mass lesions

  14. Circulation of Stars

    Science.gov (United States)

    Boitani, P.

    2016-01-01

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

  15. Natural Circulation Phenomena and Modelling for Advanced Water Cooled Reactors

    International Nuclear Information System (INIS)

    2012-03-01

    The role of natural circulation in advanced water cooled reactor design has been extended with the adoption of passive safety systems. Some designs utilize natural circulation to remove core heat during normal operation. Most passive safety systems used in evolutionary and innovative water cooled reactor designs are driven by natural circulation. The use of passive systems based on natural circulation can eliminate the costs associated with the installation, maintenance and operation of active systems that require multiple pumps with independent and redundant electric power supplies. However, considering the weak driving forces of passive systems based on natural circulation, careful design and analysis methods must be employed to ensure that the systems perform their intended functions. Several IAEA Member States with advanced reactor development programmes are actively conducting investigations of natural circulation to support the development of advanced water cooled reactor designs with passive safety systems. To foster international collaboration on the enabling technology of passive systems that utilize natural circulation, in 2004 the IAEA initiated a coordinated research project (CRP) on Natural Circulation Phenomena, Modelling and Reliability of Passive Systems that Utilize Natural Circulation. Three reports were published within the framework of this CRP. The first report (IAEA-TECDOC-1474) contains the material developed for the first IAEA training course on natural circulation in water cooled nuclear power plants. The second report (IAEA-TECDOC-1624) describes passive safety systems in a wide range of advanced water cooled nuclear power plant designs, with the goal of gaining insights into system design, operation and reliability. This third, and last, report summarizes the research studies completed by participating institutes during the CRP period.

  16. Memristor Circuits and Systems

    KAUST Repository

    Zidan, Mohammed A.

    2015-05-01

    Current CMOS-based technologies are facing design challenges related to the continuous scaling down of the minimum feature size, according to Moore’s law. Moreover, conventional computing architecture is no longer an effective way of fulfilling modern applications demands, such as big data analysis, pattern recognition, and vector processing. Therefore, there is an exigent need to shift to new technologies, at both the architecture and the device levels. Recently, memristor devices and structures attracted attention for being promising candidates for this job. Memristor device adds a new dimension for designing novel circuits and systems. In addition, high-density memristor-based crossbar is widely considered to be the essential element for future memory and bio-inspired computing systems. However, numerous challenges need to be addressed before the memristor genuinely replaces current memory and computing technologies, which is the motivation behind this research effort. In order to address the technology challenges, we begin by fabricating and modeling the memristor device. The devices fabricated at our local clean room enriched our understanding of the memristive phenomenon and enabled the experimental testing for our memristor-based circuits. Moreover, our proposed mathematical modeling for memristor behavior is an essential element for the theoretical circuit design stage. Designing and addressing the challenges of memristor systems with practical complexity, however, requires an extra step, which takes the form of a reliable and modular simulation platform. We, therefore, built a new simulation platform for the resistive crossbar, which can simulate realistic size arrays filled with real memory data. In addition, this simulation platform includes various crossbar nonidealities in order to obtain accurate simulation results. Consequently, we were able to address the significant challenges facing the high density memristor crossbar, as the building block for

  17. Basic electronic circuits

    CERN Document Server

    Buckley, P M

    1980-01-01

    In the past, the teaching of electricity and electronics has more often than not been carried out from a theoretical and often highly academic standpoint. Fundamentals and basic concepts have often been presented with no indication of their practical appli­ cations, and all too frequently they have been illustrated by artificially contrived laboratory experiments bearing little relationship to the outside world. The course comes in the form of fourteen fairly open-ended constructional experiments or projects. Each experiment has associated with it a construction exercise and an explanation. The basic idea behind this dual presentation is that the student can embark on each circuit following only the briefest possible instructions and that an open-ended approach is thereby not prejudiced by an initial lengthy encounter with the theory behind the project; this being a sure way to dampen enthusiasm at the outset. As the investigation progresses, questions inevitably arise. Descriptions of the phenomena encounte...

  18. ECCS control circuit

    International Nuclear Information System (INIS)

    Sato, Takashi.

    1986-01-01

    Purpose: To afford a sufficient margin to pressure vibrations upon starting of an automatic depressurization system by dispersing pressure vibration in suppression water due to the opening action of an automatic releaf valve in the automatic depressurization system thereby reducing the dynamic load exerted to the surface of the suppression walls. Constitution: Upon occurrence of loss of coolant accidents, an automatic releaf valve for automatic depressurization is opened to deliver the steams in the pressure vessel into the suppression pool. Since a plurality of automatic releaf valves have usually been disposed, if they are opened simultaneously, excess dynamic loads are exerted due to the pressure vibrations to the wall surface of the suppression pool. In this invention, a control circuit is disposed such that the opening timing for each of the automatic releaf valves is deviated upon occurrence of a driving signal for the automatic depressurization system to thereby disperse the pressure vibrations in the suppression water. (Kamimura, M.)

  19. A dishwasher for circuits

    CERN Multimedia

    Rosaria Marraffino

    2014-01-01

    You have always been told that electronic devices fear water. However, at the Surface Mount Devices (SMD) Workshop here at CERN all the electronic assemblies are cleaned with a machine that looks like a… dishwasher.   The circuit dishwasher. Credit: Clara Nellist.  If you think the image above shows a dishwasher, you wouldn’t be completely wrong. Apart from the fact that the whole pumping system and the case itself are made entirely from stainless steel and chemical resistant materials, and the fact that it washes electrical boards instead of dishes… it works exactly like a dishwasher. It’s a professional machine (mainly used in the pharmaceutical industry) designed to clean everything that can be washed with a water-based chemical soap. This type of treatment increases the lifetime of the electronic boards and therefore the LHC's reliability by preventing corrosion problems in the severe radiation and ozone environment of the LHC tunn...

  20. Modeling cortical circuits.

    Energy Technology Data Exchange (ETDEWEB)

    Rohrer, Brandon Robinson; Rothganger, Fredrick H.; Verzi, Stephen J.; Xavier, Patrick Gordon

    2010-09-01

    The neocortex is perhaps the highest region of the human brain, where audio and visual perception takes place along with many important cognitive functions. An important research goal is to describe the mechanisms implemented by the neocortex. There is an apparent regularity in the structure of the neocortex [Brodmann 1909, Mountcastle 1957] which may help simplify this task. The work reported here addresses the problem of how to describe the putative repeated units ('cortical circuits') in a manner that is easily understood and manipulated, with the long-term goal of developing a mathematical and algorithmic description of their function. The approach is to reduce each algorithm to an enhanced perceptron-like structure and describe its computation using difference equations. We organize this algorithmic processing into larger structures based on physiological observations, and implement key modeling concepts in software which runs on parallel computing hardware.

  1. Inductive circuit arrangements

    International Nuclear Information System (INIS)

    Mansfield, Peter; Coxon, R.J.

    1987-01-01

    A switched coil arrangement is connected in a bridge configuration of four switches S 1 , S 2 , S 3 and S 4 which are each shunted by diodes D 1 , D 2 , D 3 and D 4 so that current can flow in either direction through a coil L depending on the setting of the switches. A capacitor C is connected across the bridge through a switch S 5 to receive the inductive energy stored in coil L on breaking the current flow path through the coil. The electrostatic energy stored in capacitor C can then be used to supply current through the coil in the reverse direction either immediately or after a time delay. Coil L may be a superconductive coil. Losses in the circuit can be made up by a trickle charge of capacitor C from a separate supply V 2 . The device may be used in nuclear magnetic resonance imaging. (author)

  2. Large-Scale Ocean Circulation-Cloud Interactions Reduce the Pace of Transient Climate Change

    Science.gov (United States)

    Trossman, D. S.; Palter, J. B.; Merlis, T. M.; Huang, Y.; Xia, Y.

    2016-01-01

    Changes to the large scale oceanic circulation are thought to slow the pace of transient climate change due, in part, to their influence on radiative feedbacks. Here we evaluate the interactions between CO2-forced perturbations to the large-scale ocean circulation and the radiative cloud feedback in a climate model. Both the change of the ocean circulation and the radiative cloud feedback strongly influence the magnitude and spatial pattern of surface and ocean warming. Changes in the ocean circulation reduce the amount of transient global warming caused by the radiative cloud feedback by helping to maintain low cloud coverage in the face of global warming. The radiative cloud feedback is key in affecting atmospheric meridional heat transport changes and is the dominant radiative feedback mechanism that responds to ocean circulation change. Uncertainty in the simulated ocean circulation changes due to CO2 forcing may contribute a large share of the spread in the radiative cloud feedback among climate models.

  3. Analysis of the hydrodynamic stability of natural circulation

    International Nuclear Information System (INIS)

    Olive, J.; Baby, J.P.

    1980-01-01

    A mathematical model (EOLE) for the analysis of the stability of boilers with natural circulation is discussed. The method employed consists in linearizing one-dimensional flow equations and in integrating them while employing the Laplace transformation. The properties of a two-phase fluid are schematized by a homogeneous model with slip. The computation results in the circulation loop transfer functions and its natural modes of oscillation (frequency and damping). A discussion follows which compares results obtained with this method to those of other existing models in the case of a straight pipe with forced circulation. Agreement proved to be satisfactory. The results are then given of a parametric study involving the stability of a PWR natural circulation steam generator. These results show that the model can satisfy, at least qualitatively, trends observed empirically or obtained with other more complex theoretical models. (author)

  4. The Dynamics of Hadley Circulation Variability and Change

    Science.gov (United States)

    Davis, Nicholas Alexander

    The Hadley circulation exerts a dominant control on the surface climate of earth's tropical belt. Its converging surface winds fuel the tropical rains, while subsidence in the subtropics dries and stabilizes the atmosphere, creating deserts on land and stratocumulus decks over the oceans. Because of the strong meridional gradients in temperature and precipitation in the subtropics, any shift in the Hadley circulation edge could project as major changes in surface climate. While climate model simulations predict an expansion of the Hadley cells in response to greenhouse gas forcings, the mechanisms remain elusive. An analysis of the climatology, variability, and response of the Hadley circulation to radiative forcings in climate models and reanalyses illuminates the broader landscape in which Hadley cell expansion is realized. The expansion is a fundamental response of the atmosphere to increasing greenhouse gas concentrations as it scales with other key climate system changes, including polar amplification, increasing static stability, stratospheric cooling, and increasing global-mean surface temperatures. Multiple measures of the Hadley circulation edge latitudes co-vary with the latitudes of the eddy-driven jets on all timescales, and both exhibit a robust poleward shift in response to forcings. Further, across models there is a robust coupling between the eddy-driving on the Hadley cells and their width. On the other hand, the subtropical jet and tropopause break latitudes, two common observational proxies for the tropical belt edges, lack a strong statistical relationship with the Hadley cell edges and have no coherent response to forcings. This undermines theories for the Hadley cell width predicated on angular momentum conservation and calls for a new framework for understanding Hadley cell expansion. A numerical framework is developed within an idealized general circulation model to isolate the mean flow and eddy responses of the global atmosphere to

  5. Fluid Circulation Determined in the Isolated Bovine Lens

    Science.gov (United States)

    Candia, Oscar A.; Mathias, Richard; Gerometta, Rosana

    2012-01-01

    Purpose. In 1997, a theoretical model was developed that predicted the existence of an internal, Na+-driven fluid circulation from the poles to the equator of the lens. In the present work, we demonstrate with a novel system that fluid movement can be measured across the polar and equatorial surface areas of isolated cow lenses. We have also determined the effects of ouabain and reduced bath [Na+]. Methods. Lenses were isolated in a chamber with three compartments separated by two thin O-rings. Each compartment, anterior (A), equatorial (E), and posterior (P), was connected to a vertical capillary graduated in 0.25 μL. Capillary levels were read every 15 minutes. The protocols consisted of 2 hours in either open circuit or short circuit. The effects of ouabain and low-Na+ solutions were determined under open circuit. Results. In 21 experiments, the E capillary increased at a mean rate of 0.060 μL/min while the A and P levels decreased at rates of 0.044 and 0.037 μL/min, respectively, closely accounting for the increase in E. The first-hour flows under short circuit were approximately 40% larger than those in open-circuit conditions. The first-hour flows were always larger than those during the second hour. Preincubation of lenses with either ouabain or low-[Na+] solutions resulted in reduced rates of fluid transport. When KCl was used to replace NaCl, a transitory stimulation of fluid transport occurred. Conclusions. These experiments support that a fluid circulation consistent with the 1997 model is physiologically active. PMID:22969071

  6. Helium compressor aerodynamic design considerations for MHTGR circulators

    International Nuclear Information System (INIS)

    McDonald, C.F.

    1988-01-01

    Compressor aerodynamic design considerations for both the main and shutdown cooling circulators in the Modular High-Temperature Gas-Cooled Reactor (MHTGR) plant are addressed in this paper. A major selection topic relates to the impeller type (i.e., axial or radial flow), and the aerothermal studies leading to the selection of optimum parameters are discussed. For the conceptual designs of the main and shutdown cooling circulators, compressor blading geometries were established and helium gas flow paths defined. Both circulators are conservative by industrial standards in terms of aerodynamic and structural loading, and the blade tip speeds are particularly modest. Performance characteristics are presented, and the designs embody margin to ensure that pressure-rise growth potential can be accomodated should the circuit resistance possibly increase as the plant design advances. The axial flow impeller for the main circulator is very similar to the Fort St. Vrain (FSV) helium compressor which performs well. A significant technology base exists for the MHTGR plant circulators, and this is highlighted in the paper. (author). 15 refs, 16 figs, 12 tabs

  7. Response of an ocean general circulation model to wind and ...

    Indian Academy of Sciences (India)

    The stretched-coordinate ocean general circulation model has been designed to study the observed variability due to wind and thermodynamic forcings. The model domain extends from 60°N to 60°S and cyclically continuous in the longitudinal direction. The horizontal resolution is 5° × 5° and 9 discrete vertical levels.

  8. A general circulation model (GCM) parameterization of Pinatubo aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Lacis, A.A.; Carlson, B.E.; Mishchenko, M.I. [NASA Goddard Institute for Space Studies, New York, NY (United States)

    1996-04-01

    The June 1991 volcanic eruption of Mt. Pinatubo is the largest and best documented global climate forcing experiment in recorded history. The time development and geographical dispersion of the aerosol has been closely monitored and sampled. Based on preliminary estimates of the Pinatubo aerosol loading, general circulation model predictions of the impact on global climate have been made.

  9. Circulation Systems Past and Present

    Directory of Open Access Journals (Sweden)

    Maurice J. Freedman

    1981-01-01

    Full Text Available A review of the development of circulation systems shows two areas of change. The librarian's perception of circulation control has shifted from a broad service orientation to a narrow record-keeping approach and recently back again. The technological development of circulation sys-tems has evolved from manual systems to the online systems of today. The trade-offs and deficiencies of earlier systems in relation to the comprehensive services made possible by the online computer are detailed.

  10. Compact Circuit Preprocesses Accelerometer Output

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1993-01-01

    Compact electronic circuit transfers dc power to, and preprocesses ac output of, accelerometer and associated preamplifier. Incorporated into accelerometer case during initial fabrication or retrofit onto commercial accelerometer. Made of commercial integrated circuits and other conventional components; made smaller by use of micrologic and surface-mount technology.

  11. Comminution circuits for compact itabirites

    Directory of Open Access Journals (Sweden)

    Pedro Ferreira Pinto

    Full Text Available Abstract In the beneficiation of compact Itabirites, crushing and grinding account for major operational and capital costs. As such, the study and development of comminution circuits have a fundamental importance for feasibility and optimization of compact Itabirite beneficiation. This work makes a comparison between comminution circuits for compact Itabirites from the Iron Quadrangle. The circuits developed are: a crushing and ball mill circuit (CB, a SAG mill and ball mill circuit (SAB and a single stage SAG mill circuit (SSSAG. For the SAB circuit, the use of pebble crushing is analyzed (SABC. An industrial circuit for 25 million tons of run of mine was developed for each route from tests on a pilot scale (grinding and industrial scale. The energy consumption obtained for grinding in the pilot tests was compared with that reported by Donda and Bond. The SSSAG route had the lowest energy consumption, 11.8kWh/t and the SAB route had the highest energy consumption, 15.8kWh/t. The CB and SABC routes had a similar energy consumption of 14.4 kWh/t and 14.5 kWh/t respectively.

  12. Current-mode minimax circuit

    NARCIS (Netherlands)

    Wassenaar, R.F.

    1992-01-01

    The minimum-maximum (minimax) circuit selects the minimum and maximum of two input currents. Four transistors in matched pairs are operated in the saturation region. Because the behavior of the circuit is based on matched devices and is independent of the relationship between the drain current and

  13. Short-circuit impedance measurement

    DEFF Research Database (Denmark)

    Pedersen, Knud Ole Helgesen; Nielsen, Arne Hejde; Poulsen, Niels Kjølstad

    2003-01-01

    Methods for estimating the short-circuit impedance in the power grid are investigated for various voltage levels and situations. The short-circuit impedance is measured, preferably from naturally occurring load changes in the grid, and it is shown that such a measurement system faces different...

  14. Cell short circuit, preshort signature

    Science.gov (United States)

    Lurie, C.

    1980-01-01

    Short-circuit events observed in ground test simulations of DSCS-3 battery in-orbit operations are analyzed. Voltage signatures appearing in the data preceding the short-circuit event are evaluated. The ground test simulation is briefly described along with performance during reconditioning discharges. Results suggest that a characteristic signature develops prior to a shorting event.

  15. Enhancement of Linear Circuit Program

    DEFF Research Database (Denmark)

    Gaunholt, Hans; Dabu, Mihaela; Beldiman, Octavian

    1996-01-01

    In this report a preliminary user friendly interface has been added to the LCP2 program making it possible to describe an electronic circuit by actually drawing the circuit on the screen. Component values and other options and parameters can easily be set by the aid of the interface. The interface...

  16. The ocean circulation inverse problem

    National Research Council Canada - National Science Library

    Wunsch, C

    1996-01-01

    .... This book addresses the problem of inferring the state of the ocean circulation, understanding it dynamically, and even forecasting it through a quantitative combination of theory and observation...

  17. Automatic circuit analysis based on mask information

    International Nuclear Information System (INIS)

    Preas, B.T.; Lindsay, B.W.; Gwyn, C.W.

    1976-01-01

    The Circuit Mask Translator (CMAT) code has been developed which converts integrated circuit mask information into a circuit schematic. Logical operations, pattern recognition, and special functions are used to identify and interconnect diodes, transistors, capacitors, and resistances. The circuit topology provided by the translator is compatible with the input required for a circuit analysis program

  18. A neural circuit for angular velocity computation

    Directory of Open Access Journals (Sweden)

    Samuel B Snider

    2010-12-01

    Full Text Available In one of the most remarkable feats of motor control in the animal world, some Diptera, such as the housefly, can accurately execute corrective flight maneuvers in tens of milliseconds. These reflexive movements are achieved by the halteres, gyroscopic force sensors, in conjunction with rapidly-tunable wing-steering muscles. Specifically, the mechanosensory campaniform sensilla located at the base of the halteres transduce and transform rotation-induced gyroscopic forces into information about the angular velocity of the fly's body. But how exactly does the fly's neural architecture generate the angular velocity from the lateral strain forces on the left and right halteres? To explore potential algorithms, we built a neuro-mechanical model of the rotation detection circuit. We propose a neurobiologically plausible method by which the fly could accurately separate and measure the three-dimensional components of an imposed angular velocity. Our model assumes a single sign-inverting synapse and formally resembles some models of directional selectivity by the retina. Using multidimensional error analysis, we demonstrate the robustness of our model under a variety of input conditions. Our analysis reveals the maximum information available to the fly given its physical architecture and the mathematics governing the rotation-induced forces at the haltere's end knob.

  19. Sensitivity experiments with an adaptation model of circulation of western tropical Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Bahulayan, N.; Shaji, C.; Rao, A.D.; Dube, S.K.

    circulation at 10 m depth is controlled by both wind stress and sea surface topography. Circulation at 50 m depth is mainly controlled by thermohaline forcing and sea surface topography. The current speed in the western tropical Indian Ocean is of the order...

  20. Dynamics of large scale 3-dimensional circulation of the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Swapna, P.

    -diagnostic and prognostic modes. Such a model could identify both the local and remote forcing of the Indian Ocean circulation. The other objectives of the thesis are the following: (i) To study the steady state 3-dimensional circulation of Indian Ocean based on semi...

  1. 3D circuit integration for Vertex and other detectors

    Energy Technology Data Exchange (ETDEWEB)

    Yarema, Ray; /Fermilab

    2007-09-01

    High Energy Physics continues to push the technical boundaries for electronics. There is no area where this is truer than for vertex detectors. Lower mass and power along with higher resolution and radiation tolerance are driving forces. New technologies such as SOI CMOS detectors and three dimensional (3D) integrated circuits offer new opportunities to meet these challenges. The fundamentals for SOI CMOS detectors and 3D integrated circuits are discussed. Examples of each approach for physics applications are presented. Cost issues and ways to reduce development costs are discussed.

  2. Nanofluidic Transistor Circuits

    Science.gov (United States)

    Chang, Hsueh-Chia; Cheng, Li-Jing; Yan, Yu; Slouka, Zdenek; Senapati, Satyajyoti

    2012-02-01

    Non-equilibrium ion/fluid transport physics across on-chip membranes/nanopores is used to construct rectifying, hysteretic, oscillatory, excitatory and inhibitory nanofluidic elements. Analogs to linear resistors, capacitors, inductors and constant-phase elements were reported earlier (Chang and Yossifon, BMF 2009). Nonlinear rectifier is designed by introducing intra-membrane conductivity gradient and by asymmetric external depletion with a reverse rectification (Yossifon and Chang, PRL, PRE, Europhys Lett 2009-2011). Gating phenomenon is introduced by functionalizing polyelectrolytes whose conformation is field/pH sensitive (Wang, Chang and Zhu, Macromolecules 2010). Surface ion depletion can drive Rubinstein's microvortex instability (Chang, Yossifon and Demekhin, Annual Rev of Fluid Mech, 2012) or Onsager-Wien's water dissociation phenomenon, leading to two distinct overlimiting I-V features. Bipolar membranes exhibit an S-hysteresis due to water dissociation (Cheng and Chang, BMF 2011). Coupling the hysteretic diode with some linear elements result in autonomous ion current oscillations, which undergo classical transitions to chaos. Our integrated nanofluidic circuits are used for molecular sensing, protein separation/concentration, electrospray etc.

  3. Experimental Device for Learning of Logical Circuit Design using Integrated Circuits

    OpenAIRE

    石橋, 孝昭

    2012-01-01

    This paper presents an experimental device for learning of logical circuit design using integrated circuits and breadboards. The experimental device can be made at a low cost and can be used for many subjects such as logical circuits, computer engineering, basic electricity, electrical circuits and electronic circuits. The proposed device is effective to learn the logical circuits than the usual lecture.

  4. Labor Force

    Science.gov (United States)

    Occupational Outlook Quarterly, 2012

    2012-01-01

    The labor force is the number of people ages 16 or older who are either working or looking for work. It does not include active-duty military personnel or the institutionalized population, such as prison inmates. Determining the size of the labor force is a way of determining how big the economy can get. The size of the labor force depends on two…

  5. Integrated circuits, and design and manufacture thereof

    Science.gov (United States)

    Auracher, Stefan; Pribbernow, Claus; Hils, Andreas

    2006-04-18

    A representation of a macro for an integrated circuit layout. The representation may define sub-circuit cells of a module. The module may have a predefined functionality. The sub-circuit cells may include at least one reusable circuit cell. The reusable circuit cell may be configured such that when the predefined functionality of the module is not used, the reusable circuit cell is available for re-use.

  6. Sino-Danish Brain Circulation

    DEFF Research Database (Denmark)

    Bertelsen, Rasmus Gjedssø; Du, Xiangyun; Søndergaard, Morten Karnøe

    2014-01-01

    China is faced with urgent needs to develop an economically and environmentally sustainable economy based on innovation and knowledge. Brain circulation and research and business investments from the outside are central for this development. Sino-American brain circulation and research...... and investment by overseas researchers and entrepreneurs are well described. In that case, the US is the center of global R&D and S&T. However, the brain circulation and research and investments between a small open Scandinavian economy, such as Denmark, and the huge developing economy of China are not well...... understood. In this case, Denmark is very highly developed, but a satellite in the global R&D and S&T system. With time and the growth of China as a R&D and S&T power house, both Denmark and China will benefit from brain circulation between them. Such brain circulation is likely to play a key role in flows...

  7. Radiation-sensitive switching circuits

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.H.; Cockshott, C.P.

    1976-03-16

    A radiation-sensitive switching circuit includes a light emitting diode which from time to time illuminates a photo-transistor, the photo-transistor serving when its output reaches a predetermined value to operate a trigger circuit. In order to allow for aging of the components, the current flow through the diode is increased when the output from the transistor falls below a known level. Conveniently, this is achieved by having a transistor in parallel with the diode, and turning the transistor off when the output from the phototransistor becomes too low. The circuit is designed to control the ignition system in an automobile engine.

  8. The Maplin electronic circuits handbook

    CERN Document Server

    Tooley, Michael

    1990-01-01

    The Maplin Electronic Circuits Handbook provides pertinent data, formula, explanation, practical guidance, theory and practical guidance in the design, testing, and construction of electronic circuits. This book discusses the developments in electronics technology techniques.Organized into 11 chapters, this book begins with an overview of the common types of passive component. This text then provides the reader with sufficient information to make a correct selection of passive components for use in the circuits. Other chapters consider the various types of the most commonly used semiconductor

  9. Secure integrated circuits and systems

    CERN Document Server

    Verbauwhede, Ingrid MR

    2010-01-01

    On any advanced integrated circuit or 'system-on-chip' there is a need for security. In many applications the actual implementation has become the weakest link in security rather than the algorithms or protocols. The purpose of the book is to give the integrated circuits and systems designer an insight into the basics of security and cryptography from the implementation point of view. As a designer of integrated circuits and systems it is important to know both the state-of-the-art attacks as well as the countermeasures. Optimizing for security is different from optimizations for speed, area,

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

    International Nuclear Information System (INIS)

    Sabundjian, Gaiane; Andrade, Delvonei Alves de; Umbehaun, Pedro Ernesto; Torres, Walmir Maximo; Castro, Alfredo Jose Alvim de; Braz Filho, Francisco A.; Borges, Eduardo Madeira; Damy. Osvaldo Luiz Almeida; Torres, Eduardo

    2007-01-01

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

  11. INTEGRATED SENSOR EVALUATION CIRCUIT AND METHOD FOR OPERATING SAID CIRCUIT

    OpenAIRE

    Krüger, Jens; Gausa, Dominik

    2015-01-01

    WO15090426A1 Sensor evaluation device and method for operating said device Integrated sensor evaluation circuit for evaluating a sensor signal (14) received from a sensor (12), having a first connection (28a) for connection to the sensor and a second connection (28b) for connection to the sensor. The integrated sensor evaluation circuit comprises a configuration data memory (16) for storing configuration data which describe signal properties of a plurality of sensor control signals (26a-c). T...

  12. Reevaluation of Kori Unit 4 Natural Circulation Test

    Energy Technology Data Exchange (ETDEWEB)

    Yassin, Nassir [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Woo, Sweng Woong [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2013-10-15

    The simulation results showed that the natural circulation flow developed by density difference was capable of removing decay heat from the fuel rod. The maximum pellet centerline temperature of the hot channel showed large margin to the pellet melting temperature. The maximum coolant temperature in the hot channel was well below the saturation temperature. If steam generators provide heat sink to the primary coolant system and thus natural circulation is maintained, the integrity of the fuel in the core can be sustained with large margin. Passive cooling of reactor is inevitable in case of failures in forced cooling system such as loss of electric power for cooling pumps. Fukushima accident showed the importance of the passive core cooling. During the commissioning test of PWRs, natural circulation test is performed to demonstrate the passive core cooling by natural convection. The driving force for coolant flow is developed by the density deference along the loop multiplied by the gravitation. Using the data from 'natural circulation test' and 'RCS flow coast down test' of Kori Unit 4, fuel behavior was reevaluated by FRAPTRAN code. RCS natural circulation test of Kori Unit 4 was reevaluated by FRAPTYRAN simulation to study the fuel behavior during the flow coast down transient and at the equilibrium condition in which decay heat transport and RCS flow were stabilized.

  13. Natural Circulation with Boiling

    Energy Technology Data Exchange (ETDEWEB)

    Mathisen, R P

    1967-09-15

    A number of parameters with dominant influence on the power level at hydrodynamic instability in natural circulation, two-phase flow, have been studied experimentally. The geometrical dependent quantities were: the system driving head, the boiling channel and riser dimensions, the single-phase as well as the two phase flow restrictions. The parameters influencing the liquid properties were the system pressure and the test section inlet subcooling. The threshold of instability was determined by plotting the noise characteristics in the mass flow records against power. The flow responses to artificially obtained power disturbances at instability conditions were also measured in order to study the nature of hydrodynamic instability. The results presented give a review over relatively wide ranges of the main parameters, mainly concerning the coolant performance in both single and parallel boiling channel flow. With regard to the power limits the experimental results verified that the single boiling channel performance was intimately related to that of the parallel channels. In the latter case the additional inter-channel factors with attenuating effects were studied. Some optimum values of the parameters were observed.

  14. Modelling, simulating and optimizing boiler heating surfaces and evaporator circuits

    DEFF Research Database (Denmark)

    Sørensen, K.; Condra, T.; Houbak, Niels

    2003-01-01

    A model for optimizing the dynamic performance of boiler have been developed. Design variables related to the size of the boiler and its dynamic performance have been defined. The object function to be optimized takes the weight of the boiler and its dynamic capability into account. As constraints...... for the optimization a dynamic model for the boiler is applied. Furthermore a function for the value of the dynamic performance is included in the model. The dynamic models for simulating boiler performance consists of a model for the flue gas side, a model for the evaporator circuit and a model for the drum....... The dynamic model has been developed for the purpose of determining boiler material temperatures and heat transfer from the flue gas side to the water-/steam side in order to simulate the circulation in the evaporator circuit and hereby the water level fluctuations in the drum. The dynamic model has been...

  15. Quantum circuit behaviour

    International Nuclear Information System (INIS)

    Poulton, D.

    1989-09-01

    Single electron tunnelling in multiply connected weak link systems is considered. Using a second quantised approach the tunnel current, in both normal and superconducting systems, using perturbation theory, is derived. The tunnel currents are determined as a function of an Aharanov-Bohm phase (acquired by the electrons). Using these results, the multiply connected system is then discussed when coupled to a resonant LC circuit. The resulting dynamics of this composite system are then determined. In the superconducting case the results are compared and contrasted with flux mode behaviour seen in large superconducting weak link rings. Systems in which the predicted dynamics may be seen are also discussed. In analogy to the electron tunnelling analysis, the tunnelling of magnetic flux quanta through the weak link is also considered. Here, the voltage across the weak link, due to flux tunnelling, is determined as a function of an externally applied current. This is done for both singly and multiply connected flux systems. The results are compared and contrasted with charge mode behaviour seen in superconducting weak link systems. Finally, the behaviour of simple quantum fluids is considered when subject to an external rotation. Using a microscopic analysis it is found that the microscopic quantum behaviour of the particles is manifest on a macroscopic level. Results are derived for bosonic, fermionic and BCS pair-type systems. The connection between flux quantisation in electromagnetic systems is also made. Using these results, the dynamics of such a quantum fluid is considered when coupled to a rotating torsional oscillator. The results are compared with those found in SQUID devices. A model is also presented which discusses the possible excited state dynamics of such a fluid. (author)

  16. Dispersion Forces

    CERN Document Server

    Buhmann, Stefan Yoshi

    2012-01-01

    In this book, a modern unified theory of dispersion forces on atoms and bodies is presented which covers a broad range of advanced aspects and scenarios. Macroscopic quantum electrodynamics is shown to provide a powerful framework for dispersion forces which allows for discussing general properties like their non-additivity and the relation between microscopic and macroscopic interactions. It is demonstrated how the general results can be used to obtain dispersion forces on atoms in the presence of bodies of various shapes and materials. Starting with a brief recapitulation of volume I, this volume II deals especially with bodies of irregular shapes, universal scaling laws, dynamical forces on excited atoms, enhanced forces in cavity quantum electrodynamics, non-equilibrium forces in thermal environments and quantum friction. The book gives both the specialist and those new to the field a thorough overview over recent results in the field. It provides a toolbox for studying dispersion forces in various contex...

  17. 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

  18. Transistor and integrated circuit manufacture

    International Nuclear Information System (INIS)

    Colman, D.

    1978-01-01

    This invention relates to the manufacture of transistors and integrated circuits by ion bombardment techniques and is particularly, but not exclusively, of value in the manufacture of so-called integrated injection logic circuitry. (author)

  19. Time domain analog circuit simulation

    NARCIS (Netherlands)

    Fijnvandraat, J.G.; Houben, S.H.M.J.; Maten, ter E.J.W.; Peters, J.M.F.

    2006-01-01

    Recent developments of new methods for simulating electric circuits are described. Emphasis is put on methods that fit existing datastructures for backward differentiation formulae methods. These methods can be modified to apply to hierarchically organized datastructures, which allows for efficient

  20. Circuit design on plastic foils

    CERN Document Server

    Raiteri, Daniele; Roermund, Arthur H M

    2015-01-01

    This book illustrates a variety of circuit designs on plastic foils and provides all the information needed to undertake successful designs in large-area electronics.  The authors demonstrate architectural, circuit, layout, and device solutions and explain the reasons and the creative process behind each. Readers will learn how to keep under control large-area technologies and achieve robust, reliable circuit designs that can face the challenges imposed by low-cost low-temperature high-throughput manufacturing.   • Discusses implications of problems associated with large-area electronics and compares them to standard silicon; • Provides the basis for understanding physics and modeling of disordered material; • Includes guidelines to quickly setup the basic CAD tools enabling efficient and reliable designs; • Illustrates practical solutions to cope with hard/soft faults, variability, mismatch, aging and bias stress at architecture, circuit, layout, and device levels.

  1. Discharge quenching circuit for counters

    International Nuclear Information System (INIS)

    Karasik, A.S.

    1982-01-01

    A circuit for quenching discharges in gas-discharge detectors with working voltage of 3-5 kV based on transistors operating in the avalanche mode is described. The quenching circuit consists of a coordinating emitter follower, amplifier-shaper for avalanche key cascade control which changes potential on the counter electrodes and a shaper of discharge quenching duration. The emitter follower is assembled according to a widely used flowsheet with two transistors. The circuit permits to obtain a rectangular quenching pulse with front of 100 ns and an amplitude of up to 3.2 kV at duration of 500 μm-8 ms. Application of the quenching circuit described permits to obtain countering characteristics with the slope less than or equal to 0.02%/V and plateau extent greater than or equal to 300 V [ru

  2. Transistor and integrated circuit manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Colman, D

    1978-09-27

    This invention relates to the manufacture of transistors and integrated circuits by ion bombardment techniques and is particularly, but not exclusively, of value in the manufacture of so-called integrated injection logic circuitry.

  3. Ignition circuit for combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Becker, H W

    1977-05-26

    The invention refers to the ignition circuit for combustion engines, which are battery fed. The circuit contains a transistor and an oscillator to produce an output voltage on the secondary winding of an output transformer to supply an ignition current. The plant is controlled by an interrupter. The purpose of the invention is to form such a circuit that improved sparks for ignition are produced, on the one hand, and that on the other hand, the plant can continue to function after loss of the oscillator. The problem is solved by the battery and the secondary winding of the output transformers of the oscillator are connected via a rectifier circuit to produce a resultant total voltage with the ignition coil from the battery voltage and the rectified pulsating oscillator output.

  4. Electronic circuits, systems and standards the best of EDN

    CERN Document Server

    Hickman, Ian

    2013-01-01

    Electronic Circuits, Systems and Standards: The Best of EDN is a collection of 66 EDN articles. The topics covered in this collection are diverse but all are relevant to controlled circulation electronics. The coverage of the text includes topics about software and algorithms, such as simple random number algorithm; simple log algorithm; and efficient algorithm for repeated FFTs. The book also tackles measurement related topics, including test for identifying a Gaussian noise source; enhancing product reliability; and amplitude-locked loop speeds filter test. The text will be useful to student

  5. LH2 three-phase pump control circuit description

    International Nuclear Information System (INIS)

    Pierce, W.

    1977-05-01

    A brief description and circuit drawings are given for a pump control system. The pump is used to circulate liquid hydrogen through the cell and heat exchanger of an LH 2 target. The pump is powered by three-phase 60 cycle power, and the control unit is powered from a positive and negative 24 V dc supply available in the NIM Bin. The control unit is packaged in a double-width NIM module. Drawings are given for the pump speed indicator, function generator, and power supply

  6. Cooling Performance of Natural Circulation for a Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

  7. Modelling the Seasonal Overturning Circulation in the Red Sea

    KAUST Repository

    Yao, Fengchao

    2015-04-01

    The overturning circulation in the Red Sea exhibits a distinct seasonally reversing pattern and is studied using 50-year, high-resolution MIT general circulation model simulations. The seasonal water exchange in the Strait of Bab el Mandeb is successfully simulated, and the structures of the intruding subsurface Gulf of Aden intermediate water are in good agreement with summer observations in 2011. The model results suggest that the summer overturning circulation is driven by the combined effect of the shoaling of the thermocline in the Gulf of Aden resulting from remote winds in the Arabian Sea and an upward surface slope from the Red Sea to the Gulf of Aden set up by local surface winds in the Red Sea. For the winter overturning circulation, the climatological model mean results suggest that the surface inflow intensifies in a western boundary current in the southern Red Sea that switches to an eastern boundary current north of 24°N. The overturning is accomplished through a cyclonic recirculation and a cross-basin overturning circulation in the northern Red Sea, with major sinking occurring along a narrow band of width about 20 km along the eastern boundary and weaker upwelling along the western boundary. The northward pressure gradient force, strong vertical mixing, and horizontal mixing near the boundary are the essential dynamical components in the model\\'s winter overturning circulation.

  8. Reverse engineering of integrated circuits

    Science.gov (United States)

    Chisholm, Gregory H.; Eckmann, Steven T.; Lain, Christopher M.; Veroff, Robert L.

    2003-01-01

    Software and a method therein to analyze circuits. The software comprises several tools, each of which perform particular functions in the Reverse Engineering process. The analyst, through a standard interface, directs each tool to the portion of the task to which it is most well suited, rendering previously intractable problems solvable. The tools are generally used iteratively to produce a successively more abstract picture of a circuit, about which incomplete a priori knowledge exists.

  9. Gland system, especially for nuclear power plant circulation pumps

    International Nuclear Information System (INIS)

    Skalicky, A.; Vesely, M.

    1975-01-01

    The invention claims a gland system suitable especially for the circulation pumps of nuclear power plants. The system prevents the release of the radioactive high-pressure cooling liquid in the atmosphere. The gland system consists of at least two mechanical glands arranged in series and of the closed circuit of the cooling high-pressure medium. The respective mechanical glands are linked with by-pass branches and discharge piping. The by-pass branches accommodating control manometers and flowmeters are linked with the storage reservoir with drain pipes provided with stop fittings. (Oy)

  10. Receiver Gain Modulation Circuit

    Science.gov (United States)

    Jones, Hollis; Racette, Paul; Walker, David; Gu, Dazhen

    2011-01-01

    A receiver gain modulation circuit (RGMC) was developed that modulates the power gain of the output of a radiometer receiver with a test signal. As the radiometer receiver switches between calibration noise references, the test signal is mixed with the calibrated noise and thus produces an ensemble set of measurements from which ensemble statistical analysis can be used to extract statistical information about the test signal. The RGMC is an enabling technology of the ensemble detector. As a key component for achieving ensemble detection and analysis, the RGMC has broad aeronautical and space applications. The RGMC can be used to test and develop new calibration algorithms, for example, to detect gain anomalies, and/or correct for slow drifts that affect climate-quality measurements over an accelerated time scale. A generalized approach to analyzing radiometer system designs yields a mathematical treatment of noise reference measurements in calibration algorithms. By treating the measurements from the different noise references as ensemble samples of the receiver state, i.e. receiver gain, a quantitative description of the non-stationary properties of the underlying receiver fluctuations can be derived. Excellent agreement has been obtained between model calculations and radiometric measurements. The mathematical formulation is equivalent to modulating the gain of a stable receiver with an externally generated signal and is the basis for ensemble detection and analysis (EDA). The concept of generating ensemble data sets using an ensemble detector is similar to the ensemble data sets generated as part of ensemble empirical mode decomposition (EEMD) with exception of a key distinguishing factor. EEMD adds noise to the signal under study whereas EDA mixes the signal with calibrated noise. It is mixing with calibrated noise that permits the measurement of temporal-functional variability of uncertainty in the underlying process. The RGMC permits the evaluation of EDA by

  11. Artificial immune system algorithm in VLSI circuit configuration

    Science.gov (United States)

    Mansor, Mohd. Asyraf; Sathasivam, Saratha; Kasihmuddin, Mohd Shareduwan Mohd

    2017-08-01

    In artificial intelligence, the artificial immune system is a robust bio-inspired heuristic method, extensively used in solving many constraint optimization problems, anomaly detection, and pattern recognition. This paper discusses the implementation and performance of artificial immune system (AIS) algorithm integrated with Hopfield neural networks for VLSI circuit configuration based on 3-Satisfiability problems. Specifically, we emphasized on the clonal selection technique in our binary artificial immune system algorithm. We restrict our logic construction to 3-Satisfiability (3-SAT) clauses in order to outfit with the transistor configuration in VLSI circuit. The core impetus of this research is to find an ideal hybrid model to assist in the VLSI circuit configuration. In this paper, we compared the artificial immune system (AIS) algorithm (HNN-3SATAIS) with the brute force algorithm incorporated with Hopfield neural network (HNN-3SATBF). Microsoft Visual C++ 2013 was used as a platform for training, simulating and validating the performances of the proposed network. The results depict that the HNN-3SATAIS outperformed HNN-3SATBF in terms of circuit accuracy and CPU time. Thus, HNN-3SATAIS can be used to detect an early error in the VLSI circuit design.

  12. Spectral Purity Enhancement via Polyphase Multipath Circuits

    NARCIS (Netherlands)

    Mensink, E.; Klumperink, Eric A.M.; Nauta, Bram

    2004-01-01

    The central question of this paper is: can we enhance the spectral purity of nonlinear circuits by using polyphase multipath circuits? The basic idea behind polyphase multipath circuits is to split the nonlinear circuits into two or more paths and exploit phase differences between these paths to

  13. Distortion Cancellation via Polyphase Multipath Circuits

    NARCIS (Netherlands)

    Mensink, E.; Klumperink, Eric A.M.; Nauta, Bram

    The central question of this paper is: can we enhance the spectral purity of nonlinear circuits with the help of polyphase multipath circuits. Polyphase multipath circuits are circuits with two or more paths that exploit phase differences between the paths to cancel unwanted signals. It turns out

  14. Dynamic theory for the mesoscopic electric circuit

    International Nuclear Information System (INIS)

    Chen Bin; Shen Xiaojuan; Li Youquan; Sun LiLy; Yin Zhujian

    2005-01-01

    The quantum theory for mesoscopic electric circuit with charge discreteness is briefly described. The minibands of quasienergy in LC design mesoscopic electric circuit have been found. In the mesoscopic 'pure' inductance design circuit, just like in the mesoscopic metallic rings, the quantum dynamic characteristics have been obtained explicitly. In the 'pure' capacity design circuit, the Coulomb blockade had also been addressed

  15. Multi-Layer E-Textile Circuits

    Science.gov (United States)

    Dunne, Lucy E.; Bibeau, Kaila; Mulligan, Lucie; Frith, Ashton; Simon, Cory

    2012-01-01

    Stitched e-textile circuits facilitate wearable, flexible, comfortable wearable technology. However, while stitched methods of e-textile circuits are common, multi-layer circuit creation remains a challenge. Here, we present methods of stitched multi-layer circuit creation using accessible tools and techniques.

  16. Versatile resonance-tracking circuit for acoustic levitation experiments.

    Science.gov (United States)

    Baxter, K; Apfel, R E; Marston, P L

    1978-02-01

    Objects can be levitated by radiation pressure forces in an acoustic standing wave. In many circumstances it is important that the standing wave frequency remain locked on an acoustic resonance despite small changes in the resonance frequency. A self-locking oscillator circuit is described which tracks the resonance frequency by sensing the magnitude of the transducer current. The tracking principle could be applied to other resonant systems.

  17. Instrumentation and test gear circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Instrumentation and Test Gear Circuits Manual provides diagrams, graphs, tables, and discussions of several types of practical circuits. The practical circuits covered in this book include attenuators, bridges, scope trace doublers, timebases, and digital frequency meters. Chapter 1 discusses the basic instrumentation and test gear principles. Chapter 2 deals with the design of passive attenuators, and Chapter 3 with passive and active filter circuits. The subsequent chapters tackle 'bridge' circuits, analogue and digital metering techniques and circuitry, signal and waveform generation, and p

  18. Different forces

    CERN Multimedia

    1982-01-01

    The different forces, together with a pictorial analogy of how the exchange of particles works. The table lists the relative strength of the couplings, the quanta associated with the force fields and the bodies or phenomena in which they have a dominant role.

  19. Labor Force

    Science.gov (United States)

    Occupational Outlook Quarterly, 2010

    2010-01-01

    The labor force is the number of people aged 16 or older who are either working or looking for work. It does not include active-duty military personnel or institutionalized people, such as prison inmates. Quantifying this total supply of labor is a way of determining how big the economy can get. Labor force participation rates vary significantly…

  20. Installations having pressurised fluid circuits

    International Nuclear Information System (INIS)

    Rigg, S.; Grant, J.

    1977-01-01

    Reference is made to nuclear installations having pressurised coolant flow circuits. Breaches in such circuits may quickly result in much damage to the plant. Devices such as non-return valves, orifice plates, and automatically operated shut-off valves have been provided to prevent or reduce fluid flow through a breached pipe line, but such devices have several disadvantages; they may present large restrictions to normal flow of coolant, and may depend on the operation of ancillary equipment, with consequent delay in bringing them into operation in an emergency. Other expedients that have been adopted to prevent or reduce reverse flow through an upstream breach comprise various forms of hydraulic counter flow brakes. The arrangement described has at least one variable fluid brake comprising a fluidic device connected into a duct in the pressurised circuit, the device having an inlet, an outlet, a vortex chamber between the inlet and outlet, a control jet for introducing fluid into the vortex chamber, connections communicating the inlet and the outlet into one part of the circuit and the control jet into another region at a complementary pressure so that, in the event of a breach in the circuit in one region, fluid passes from the other region to enter the vortex chamber to stimulate pressure to create a flow restricting vortex in the chamber that reduces flow through the breach. The system finds particular application to stream generating pressure tube reactors, such as the steam generating heavy water reactor at UKAEA, Winfrith. (U.K.)

  1. 30 CFR 75.601-1 - Short circuit protection; ratings and settings of circuit breakers.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Short circuit protection; ratings and settings... Trailing Cables § 75.601-1 Short circuit protection; ratings and settings of circuit breakers. Circuit breakers providing short circuit protection for trailing cables shall be set so as not to exceed the...

  2. 30 CFR 77.506 - Electric equipment and circuits; overload and short-circuit protection.

    Science.gov (United States)

    2010-07-01

    ... short-circuit protection. 77.506 Section 77.506 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... circuits; overload and short-circuit protection. Automatic circuit-breaking devices or fuses of the correct type and capacity shall be installed so as to protect all electric equipment and circuits against short...

  3. 30 CFR 75.518 - Electric equipment and circuits; overload and short circuit protection.

    Science.gov (United States)

    2010-07-01

    ... short circuit protection. 75.518 Section 75.518 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... Equipment-General § 75.518 Electric equipment and circuits; overload and short circuit protection... installed so as to protect all electric equipment and circuits against short circuit and overloads. Three...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  5. Indian summer monsoon forcing on the deglacial polar cold reversals

    Indian Academy of Sciences (India)

    Virupaxa K Banakar

    2017-09-01

    Sep 1, 2017 ... because CO2, the fundamental forcing for deglaciation, and Atlantic meridional overturning circulation, ... The role of CO2 in causing these deglacial cold ..... Temperature changes in the polar regions with reference to their ...

  6. Nucla circulating atmospheric fluidized bed demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    Keith, Raymond E.

    1991-10-01

    Colorado-Ute Electric Association began a study to evaluate options for upgrading and extending the life of its Nucla power station in 1982. Located in southwestern Colorado near the town of Nucla, this station was commissioned in 1959 with a local bituminous coal as its design fuel for three identical stoker-fired units, each rated at 12.6 MW(e). Poor station efficiency, high fuel costs, and spiraling boiler maintenance costs forced the Nucla Station into low priority in the CUEA dispatch order as early as 1981. Among the options CUEA considered was to serve as a host utility to demonstrate Atmospheric Fluidized Bed Combustion (AFBC) technology. The anticipated environmental benefits and apparent attractive economics of a circulating AFBC led to Colorado-Ute's decision to proceed with the design and construction of a demonstration project in 1984 at the Nucla facility.

  7. Instability of single-phase natural circulation

    International Nuclear Information System (INIS)

    Xie Heng; Zhang Jinling; Jia Dounan

    1997-01-01

    The author has investigated the instability of single-phase flows in natural circulation loops. The momentum equation and energy equation are made dimensionless according to some definitions, and some important dimensionless parameters are gotten. The authors decomposed the mean mass flowrate and temperature into a steady solution and a small disturbance equations. Through solving the disturbance equations, the authors get the neutral stability curves. The authors have studied the effect of the two parameters which represent the ratio of buoyancy force to the friction loss in the loop on the stability of loops. The authors also have studied the effect of the difference of height between the center of heat source and the heat sink on the stability

  8. Experimental studies in a single-phase parallel channel natural circulation system. Preliminary results

    International Nuclear Information System (INIS)

    Bodkha, Kapil; Pilkhwal, D.S.; Jana, S.S.; Vijayan, P.K.

    2016-01-01

    Natural circulation systems find extensive applications in industrial engineering systems. One of the applications is in nuclear reactor where the decay heat is removed by natural circulation of the fluid under off-normal conditions. The upcoming reactor designs make use of natural circulation in order to remove the heat from core under normal operating conditions also. These reactors employ multiple vertical fuel channels with provision of on-power refueling/defueling. Natural circulation systems are relatively simple, safe and reliable when compared to forced circulation systems. However, natural circulation systems are prone to encounter flow instabilities which are highly undesirable for various reasons. Presence of parallel channels under natural circulation makes the system more complicated. To examine the behavior of parallel channel system, studies were carried out for single-phase natural circulation flow in a multiple vertical channel system. The objective of the present work is to study the flow behavior of the parallel heated channel system under natural circulation for different operating conditions. Steady state and transient studies have been carried out in a parallel channel natural circulation system with three heated channels. The paper brings out the details of the system considered, different cases analyzed and preliminary results of studies carried out on a single-phase parallel channel system.

  9. Contrôle des Circuits Auxiliaires des PFW (arrêt machines 2002/2003)

    CERN Document Server

    Ottaviani, J

    2003-01-01

    Les PFW sont des nappes polaires installées sur les pôles des aimants du PS. Elles sont au nombre de 4 par unité d aimant et constituées d un circuit principal (dans lequel circule le courant désiré selon le cycle magnétique utilisé) et de circuits auxiliaires. Les circuits auxiliaires sont des enroulements de correction (boucles de tour et pick-up brasés sur les enroulements). Pendant la variation du champ magnétique de l aimant PS, on utilise des tensions induites dans ces circuits auxiliaires pour corriger les erreurs de champ dues aux courants de Foucault dans la chambre à vide. Chaque année, pendant l arrêt machine, on vérifie si les caractéristiques des circuits auxiliaires correspondent aux normes (mesures des résistances des boucles de tours, résistances entre pick-up et isolation des circuits) afin de faire un suivi. Les 404 PFW sont ainsi vérifiées. Dans cette note, on ne relèvera que les PFW ayant des défauts (valeurs hors tolérances, boucles ouvertes ou en court-circuit, déf...

  10. Multiplication circuit for particle identification

    International Nuclear Information System (INIS)

    Gerlier, Jean

    1962-01-01

    After having commented some characteristics of the particles present in a cyclotron, and their interactions, this report addresses the development and the implementation of a method and a device for selecting and counting particles. The author presents the principle and existing techniques of selection. In comparison with an existing device, the proportional counter and the scintillator are replaced by junctions: a surface barrier type junction (a silicon N layer with a very thin oxygen layer playing the role of the P layer), and lithium-based junction (a silicon P type layer made intrinsic by migration of lithium). The author then describes the developed circuit and assembly (background of the choice of a multiplication circuit), and their operation. In the next part, he presents the performed tests and discuses the obtained results. He finally outlines the benefits of the herein presented circuit [fr

  11. Wiring of electronic evaluation circuits

    International Nuclear Information System (INIS)

    Bauer, R.; Svoboda, Z.

    1977-01-01

    The wiring is described of electronic evaluation circuits for the automatic viewing of photographic paper strip negatives on which line tracks with an angular scatter relative to the spectrograph longitudinal axis were recorded during the oblique flight of nuclear particles during exposure in the spectrograph. In coincidence evaluation, the size of the angular scatter eventually requires that evaluation dead time be increased. The equipment consists of minimally two fixed registers and a block of logic circuits whose output is designed such as will allow connection to equipment for recording signals corresponding to the number of tracks on the film. The connection may be implemented using integrated circuits guaranteeing high operating reliability and life. (J.B.)

  12. Counterpulse railgun energy recovery circuit

    International Nuclear Information System (INIS)

    Honig, E.M.

    1986-01-01

    This patent describes a counterpulse railgun energy recovery circuit for propelling a projectile along a railgun the counterpulse railgun energy recovery circuit consists of: a railgun having an effective inductance; a source inductor initially charged to an initial current; current means for initially charging the source inductor to the initial current; first current-zero type switching means; second current-zero type switching; third current-zero type switching; muzzle current-zero type switching means; transfer capacitor, the transfer capacitor is for cooperating with the first, second, third, and muzzle current-zero type switching means for providing a resonant circuit for transferring current from the source inductor to the effective inductance of the railgun during the propelling of a projectile along the railgun and for returning current from the effective inductance of the railgun to the source inductance after the projectile has exited the railgun

  13. Vertically Integrated Circuits at Fermilab

    International Nuclear Information System (INIS)

    Deptuch, Grzegorz; Demarteau, Marcel; Hoff, James; Lipton, Ronald; Shenai, Alpana; Trimpl, Marcel; Yarema, Raymond; Zimmerman, Tom

    2009-01-01

    The exploration of the vertically integrated circuits, also commonly known as 3D-IC technology, for applications in radiation detection started at Fermilab in 2006. This paper examines the opportunities that vertical integration offers by looking at various 3D designs that have been completed by Fermilab. The emphasis is on opportunities that are presented by through silicon vias (TSV), wafer and circuit thinning and finally fusion bonding techniques to replace conventional bump bonding. Early work by Fermilab has led to an international consortium for the development of 3D-IC circuits for High Energy Physics. The consortium has submitted over 25 different designs for the Fermilab organized MPW run organized for the first time.

  14. Experimental determination of heat transfer critical conditions in water forced convection at low pressure in a circular channel

    International Nuclear Information System (INIS)

    Fernandes, M.P.

    1973-02-01

    An experimental determination was made of heat transfer critical conditions in a circular channel, uniformly heated, and internally cooled by water in ascending forced convection, under a pressure slightly above atmospheric pressure. Measurements were made of water flow, pressure, electric power temperature and heating, and a systematic analysis was made of the system's parameters. The values obtained for the heat critical flux are circa 50% lower than those predicted by Becker and Biasi and this is accounted to flowing instabilities of thermo-hydrodynamic nature. It is suggested that the flowing channels of circuits aiming at the study of the boiling crisis phenomenon be expanded in its upper extremity, and that the coolant circulation be kept through a pump with a pressure X flow characteristic as vertical as possible

  15. Southern Hemisphere extratropical circulation: Recent trends and natural variability

    Science.gov (United States)

    Thomas, Jordan L.; Waugh, Darryn W.; Gnanadesikan, Anand

    2015-07-01

    Changes in the Southern Annular Mode (SAM), Southern Hemisphere (SH) westerly jet location, and magnitude are linked with changes in ocean circulation along with ocean heat and carbon uptake. Recent trends have been observed in these fields but not much is known about the natural variability. Here we aim to quantify the natural variability of the SH extratropical circulation by using Coupled Model Intercomparison Project Phase 5 (CMIP5) preindustrial control model runs and compare with the observed trends in SAM, jet magnitude, and jet location. We show that trends in SAM are due partly to external forcing but are not outside the natural variability as described by these models. Trends in jet location and magnitude, however, lie outside the unforced natural variability but can be explained by a combination of natural variability and the ensemble mean forced trend. These results indicate that trends in these three diagnostics cannot be used interchangeably.

  16. Fermionic models with superconducting circuits

    Energy Technology Data Exchange (ETDEWEB)

    Las Heras, Urtzi; Garcia-Alvarez, Laura; Mezzacapo, Antonio; Lamata, Lucas [University of the Basque Country UPV/EHU, Department of Physical Chemistry, Bilbao (Spain); Solano, Enrique [University of the Basque Country UPV/EHU, Department of Physical Chemistry, Bilbao (Spain); IKERBASQUE, Basque Foundation for Science, Bilbao (Spain)

    2015-12-01

    We propose a method for the efficient quantum simulation of fermionic systems with superconducting circuits. It consists in the suitable use of Jordan-Wigner mapping, Trotter decomposition, and multiqubit gates, be with the use of a quantum bus or direct capacitive couplings. We apply our method to the paradigmatic cases of 1D and 2D Fermi-Hubbard models, involving couplings with nearest and next-nearest neighbours. Furthermore, we propose an optimal architecture for this model and discuss the benchmarking of the simulations in realistic circuit quantum electrodynamics setups. (orig.)

  17. Circuit modeling for electromagnetic compatibility

    CERN Document Server

    Darney, Ian B

    2013-01-01

    Very simply, electromagnetic interference (EMI) costs money, reduces profits, and generally wreaks havoc for circuit designers in all industries. This book shows how the analytic tools of circuit theory can be used to simulate the coupling of interference into, and out of, any signal link in the system being reviewed. The technique is simple, systematic and accurate. It enables the design of any equipment to be tailored to meet EMC requirements. Every electronic system consists of a number of functional modules interconnected by signal links and power supply lines. Electromagnetic interference

  18. Relative ultrasound energy measurement circuit

    OpenAIRE

    Gustafsson, E.Martin I.; Johansson, Jonny; Delsing, Jerker

    2005-01-01

    A relative ultrasound energy estimation circuit has been designed in a standard 0.35-μm CMOS process, to be a part of a thumb size internet connected wireless ultrasound measurement system. This circuit measures the relative energy between received ultrasound pulses, and presents an output signal that is linear to the received energy. Post-layout simulations indicate 7 bit linearity for 500 mV input signals, 5 μsec startup and stop times, 2.6 mW power consumption during active state. The acti...

  19. Simplified design of filter circuits

    CERN Document Server

    Lenk, John

    1999-01-01

    Simplified Design of Filter Circuits, the eighth book in this popular series, is a step-by-step guide to designing filters using off-the-shelf ICs. The book starts with the basic operating principles of filters and common applications, then moves on to describe how to design circuits by using and modifying chips available on the market today. Lenk's emphasis is on practical, simplified approaches to solving design problems.Contains practical designs using off-the-shelf ICsStraightforward, no-nonsense approachHighly illustrated with manufacturer's data sheets

  20. Programming languages for circuit design.

    Science.gov (United States)

    Pedersen, Michael; Yordanov, Boyan

    2015-01-01

    This chapter provides an overview of a programming language for Genetic Engineering of Cells (GEC). A GEC program specifies a genetic circuit at a high level of abstraction through constraints on otherwise unspecified DNA parts. The GEC compiler then selects parts which satisfy the constraints from a given parts database. GEC further provides more conventional programming language constructs for abstraction, e.g., through modularity. The GEC language and compiler is available through a Web tool which also provides functionality, e.g., for simulation of designed circuits.

  1. Endogenous money, circuits and financialization

    OpenAIRE

    Malcolm Sawyer

    2013-01-01

    This paper locates the endogenous money approach in a circuitist framework. It argues for the significance of the credit creation process for the evolution of the economy and the absence of any notion of ‘neutrality of money’. Clearing banks are distinguished from other financial institutions as the providers of initial finance in a circuit whereas other financial institutions operate in a final finance circuit. Financialization is here viewed in terms of the growth of financial assets an...

  2. Structure and variances of equatorial zonal circulation in a multimodel ensemble

    Energy Technology Data Exchange (ETDEWEB)

    Yu, B. [Environment Canada, Climate Data and Analysis Section, Climate Research Division, Toronto, ON (Canada); Zwiers, F.W. [University of Victoria, Pacific Climate Impacts Consortium, Victoria, BC (Canada); Boer, G.J. [Environment Canada, Canadian Centre for Climate Modeling and Analysis, Climate Research Division, Victoria, BC (Canada); Ting, M.F. [Columbia University, Lamont-Doherty Earth Observatory, Palisades, NY (United States)

    2012-11-15

    The structure and variance of the equatorial zonal circulation, as characterized by the atmospheric mass flux in the equatorial zonal plane, is examined and inter-compared in simulations from 9 CMIP3 coupled climate models with multiple ensemble members and the NCEP-NCAR and ERA-40 reanalyses. The climate model simulations analyzed here include twentieth century (20C3M) and twenty-first century (SRES A1B) simulations. We evaluate the 20C3M modeled zonal circulations by comparing them with those in the reanalyses. We then examine the variability of the circulation, its changes with global warming, and the associated thermodynamic maintenance. The tropical zonal circulation involves three major components situated over the Pacific, Indian, and Atlantic oceans. The three cells are supported by the corresponding diabatic heating extending deeply throughout the troposphere, with heating centers apparent in the mid-troposphere. Seasonal features appear in the zonal circulation, including variations in its intensity and longitudinal migration. Most models, and hence the multi-model mean, represent the annual and seasonal features of the circulation and the associated heating reasonably well. The multi-model mean reproduces the observed climatology better than any individual model, as indicated by the spatial pattern correlation and mean square difference of the mass flux and the diabatic heating compared to the reanalysis based values. Projected changes in the zonal circulation under A1B forcing are dominated by mass flux changes over the Pacific and Indian oceans. An eastward shift of the Pacific Walker circulation is clearly evident with global warming, with anomalous rising motion apparent over the equatorial central Pacific and anomalous sinking motions in the west and east, which favors an overall strengthening of the Walker circulation. The zonal circulation weakens and shifts westwards over the Indian Ocean under external forcing, whereas it strengthens and shifts

  3. Climatology of the HOPE-G global ocean general circulation model - Sea ice general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Legutke, S. [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany); Maier-Reimer, E. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

    1999-12-01

    The HOPE-G global ocean general circulation model (OGCM) climatology, obtained in a long-term forced integration is described. HOPE-G is a primitive-equation z-level ocean model which contains a dynamic-thermodynamic sea-ice model. It is formulated on a 2.8 grid with increased resolution in low latitudes in order to better resolve equatorial dynamics. The vertical resolution is 20 layers. The purpose of the integration was both to investigate the models ability to reproduce the observed general circulation of the world ocean and to obtain an initial state for coupled atmosphere - ocean - sea-ice climate simulations. The model was driven with daily mean data of a 15-year integration of the atmosphere general circulation model ECHAM4, the atmospheric component in later coupled runs. Thereby, a maximum of the flux variability that is expected to appear in coupled simulations is included already in the ocean spin-up experiment described here. The model was run for more than 2000 years until a quasi-steady state was achieved. It reproduces the major current systems and the main features of the so-called conveyor belt circulation. The observed distribution of water masses is reproduced reasonably well, although with a saline bias in the intermediate water masses and a warm bias in the deep and bottom water of the Atlantic and Indian Oceans. The model underestimates the meridional transport of heat in the Atlantic Ocean. The simulated heat transport in the other basins, though, is in good agreement with observations. (orig.)

  4. Joule-Thief Circuit Performance for Electricity Energy Saving of Emergency Lamps

    Science.gov (United States)

    Nuryanto Budisusila, Eka; Arifin, Bustanul

    2017-04-01

    The alternative energy such as battery as power source is required as energy source failures. The other need is outdoor lighting. The electrical power source is expected to be a power saving, optimum and has long life operating. The Joule-Thief circuit is one of solution method for energy saving by using raised electromagnetic force on cored coil when there is back-current. This circuit has a transistor operated as a switch to cut voltage and current flowing along the coils. The present of current causing magnetic induction and generates energy. Experimental prototype was designed by using battery 1.5V to activate Light Emitting Diode or LED as load. The LED was connected in parallel or serial circuit configuration. The result show that the joule-thief circuit able to supply LED circuits up to 40 LEDs.

  5. PWR hot leg natural circulation modeling with MELCOR code

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-31

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

  6. PWR hot leg natural circulation modeling with MELCOR code

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

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

  7. Multiple states in the late Eocene ocean circulation

    Science.gov (United States)

    Baatsen, M. L. J.; von der Heydt, A. S.; Kliphuis, M.; Viebahn, J.; Dijkstra, H. A.

    2018-04-01

    The Eocene-Oligocene Transition (EOT) marks a major step within the Cenozoic climate in going from a greenhouse into an icehouse state, with the formation of a continental-scale Antarctic ice sheet. The roles of steadily decreasing CO2 concentrations versus changes in ocean circulation at the EOT are still debated and the threshold for Antarctic glaciation is obscured by uncertainties in global geometry. Here, a detailed study of the late Eocene ocean circulation is carried out using an ocean general circulation model under two slightly different geography reconstructions of the middle-to-late Eocene (38 Ma). Using the same atmospheric forcing, both geographies give a profoundly different equilibrium ocean circulation state. The underlying reason for this sensitivity is the presence of multiple equilibria characterised by either North or South Pacific deep water formation. A possible shift from a southern towards a northern overturning circulation would result in significant changes in the global heat distribution and consequently make the Southern Hemisphere climate more susceptible for significant cooling and ice sheet formation on Antarctica.

  8. Implementation of Chua's circuit using simulated inductance

    Science.gov (United States)

    Gopakumar, K.; Premlet, B.; Gopchandran, K. G.

    2011-05-01

    In this study we describe how to build an inductorless version of the classic Chua's circuit. A suitable inductor for Chua's circuit is often hard to procure. The required inductor for the circuit is designed using simple circuit elements such as resistors, capacitors and operational amplifiers. The complete circuit can be implemented by using off-the-shelf components, and it can readily be integrated on a single chip. This design of Chua's circuit allows the original dynamics to be slowed down to just a few hertz, enabling implementation of sophisticated control schemes without severe time restrictions. Another novel feature of the circuit is that losses associated with capacitors due to leakages can easily be compensated by providing negative resistance using the same setup. The chaotic behaviour of the circuit is verified by PSpice and Multisim simulation and also by experimental study on a circuit breadboard. The results give excellent agreement with each other and with the results of previous investigators.

  9. The Invertibility, Explicit Determinants, and Inverses of Circulant and Left Circulant and g-Circulant Matrices Involving Any Continuous Fibonacci and Lucas Numbers

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available Circulant matrices play an important role in solving delay differential equations. In this paper, circulant type matrices including the circulant and left circulant and g-circulant matrices with any continuous Fibonacci and Lucas numbers are considered. Firstly, the invertibility of the circulant matrix is discussed and the explicit determinant and the inverse matrices by constructing the transformation matrices are presented. Furthermore, the invertibility of the left circulant and g-circulant matrices is also studied. We obtain the explicit determinants and the inverse matrices of the left circulant and g-circulant matrices by utilizing the relationship between left circulant, g-circulant matrices and circulant matrix, respectively.

  10. Neuromorphic circuits impart a sense of touch

    Science.gov (United States)

    Bartolozzi, Chiara

    2018-06-01

    The sense of touch is the ability to perceive consistency, texture, and shape of objects that we manipulate, and the forces we exchange with them. Touch is a source of information that we effortlessly decode to smoothly and naturally grasp and manipulate objects, maintain our posture while walking, or avoid stumbling into obstacles, allowing us to plan, adapt, and correct actions in an ever-changing external world. As such, artificial devices, such as robots or prostheses, that aim to accomplish similar tasks must possess artificial tactile-sensing systems. On page 998 of this issue, Kim et al. (1) report on a “neuromorphic” tactile sensory system based on organic, flexible, electronic circuits that can measure the force applied on the sensing regions. The encoding of the signal is similar to that used by human nerves that are sensitive to tactile stimuli (mechanoreceptors), so the device outputs can substitute for them and communicate with other nerves (e.g., residual nerve fibers of amputees or motor neurons). The proposed system exploits organic electronics that allow for three-dimensional printing of flexible structures that conform to large curved surfaces, as required for placing sensors on robots (2) and prostheses.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

  12. Self-organizing maps applied to two-phase flow on natural circulation loop study

    International Nuclear Information System (INIS)

    Castro, Leonardo Ferreira

    2016-01-01

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

  13. Advanced circuit simulation using Multisim workbench

    CERN Document Server

    Báez-López, David; Cervantes-Villagómez, Ofelia Delfina

    2012-01-01

    Multisim is now the de facto standard for circuit simulation. It is a SPICE-based circuit simulator which combines analog, discrete-time, and mixed-mode circuits. In addition, it is the only simulator which incorporates microcontroller simulation in the same environment. It also includes a tool for printed circuit board design.Advanced Circuit Simulation Using Multisim Workbench is a companion book to Circuit Analysis Using Multisim, published by Morgan & Claypool in 2011. This new book covers advanced analyses and the creation of models and subcircuits. It also includes coverage of transmissi

  14. Digital circuit boards mach 1 GHz

    CERN Document Server

    Morrison, Ralph

    2012-01-01

    A unique, practical approach to the design of high-speed digital circuit boards The demand for ever-faster digital circuit designs is beginning to render the circuit theory used by engineers ineffective. Digital Circuit Boards presents an alternative to the circuit theory approach, emphasizing energy flow rather than just signal interconnection to explain logic circuit behavior. The book shows how treating design in terms of transmission lines will ensure that the logic will function, addressing both storage and movement of electrical energy on these lines. It cove

  15. Clocking Scheme for Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1998-01-01

    A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed.......A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed....

  16. Prospects of increasing the power of a two-circuit geothermal power plant

    International Nuclear Information System (INIS)

    Alkhasov, A.B.

    2001-01-01

    The results of analysis of the thermodynamical cycle of the geothermal NPPs secondary circuit with various versions of the geothermal circulation system are presented. It is shown, that the technological scheme with horizontal well is the optimal one. The conclusion is made that by further assimilation of thermal power with application of the experience, accumulated by petroleum specialist, it is necessary to built up geothermal circulation systems with horizontal wells. This will sharply increase the indices of the geothermal branch, its efficiency and competivity as compared to the traditional power engineering [ru

  17. Unbalanced Neuronal Circuits in Addiction

    OpenAIRE

    Volkow, Nora D.; Wang, Gen-Jack; Tomasi, Dardo; Baler, Ruben D.

    2013-01-01

    Through sequential waves of drug-induced neurochemical stimulation, addiction co-opts the brain's neuronal circuits that mediate reward, motivation, , to behavioral inflexibility and a severe disruption of self-control and compulsive drug intake. Brain imaging technologies have allowed neuroscientists to map out the neural landscape of addiction in the human brain and to understand how drugs modify it.

  18. A Low Noise Electronic Circuit

    NARCIS (Netherlands)

    Annema, Anne J.; Leenaerts, Dominicus M.W.; de Vreede, Petrus W.H.

    2002-01-01

    An electronic circuit, which can be used as a Low Noise Amplifier (LNA), comprises two complementary Field Effect Transistors (M1, M2; M5, M6), each having a gate, a source and a drain. The gates are connected together as a common input terminal, and the drains are connected together as a

  19. Circuit design for RF transceivers

    CERN Document Server

    Leenaerts, Domine; Vaucher, Cicero S

    2007-01-01

    Second edition of this successful 2001 RF Circuit Design book, has been updated, latest technology reviews have been added as well as several actual case studies. Due to the authors being active in industry as well as academia, this should prove to be an essential guide on RF Transceiver Design for students and engineers.

  20. Integrated Circuit Stellar Magnitude Simulator

    Science.gov (United States)

    Blackburn, James A.

    1978-01-01

    Describes an electronic circuit which can be used to demonstrate the stellar magnitude scale. Six rectangular light-emitting diodes with independently adjustable duty cycles represent stars of magnitudes 1 through 6. Experimentally verifies the logarithmic response of the eye. (Author/GA)

  1. Simulated annealing and circuit layout

    NARCIS (Netherlands)

    Aarts, E.H.L.; Laarhoven, van P.J.M.

    1991-01-01

    We discuss the problem of approximately sotvlng circuit layout problems by simulated annealing. For this we first summarize the theoretical concepts of the simulated annealing algorithm using Ihe theory of homogeneous and inhomogeneous Markov chains. Next we briefly review general aspects of the

  2. Proper Sizing of Circulation Pumps

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Nørgaard, Jørgen

    2007-01-01

    The paper describes the preliminary results from field tests of replacing various types of old pumps used for circulating water in heating systems in single- and double-family houses with new types of pumps. The tests were carried out in Denmark for the Danish Electricity Savings Trust, but the r......The paper describes the preliminary results from field tests of replacing various types of old pumps used for circulating water in heating systems in single- and double-family houses with new types of pumps. The tests were carried out in Denmark for the Danish Electricity Savings Trust...

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

    International Nuclear Information System (INIS)

    Gou Junli; Qiu Suizheng; Su Guanghui; Jia Dounan

    2006-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

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

    International Nuclear Information System (INIS)

    Lemos, Wanderley F.; Su, Jian; Faccini, Jose L.H.

    2013-01-01

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

  6. On-chip microwave circulators using quantum Hall plasmonics

    Science.gov (United States)

    Mahoney, Alice; Colless, James; Pauka, Sebastian; Hornibrook, John; Doherty, Andrew; Reilly, David; Peeters, Lucas; Fox, Eli; Goldhaber-Gordon, David; Kou, Xuefeng; Pan, Lei; Wang, Kang; Watson, John; Gardner, Geoffrey; Manfra, Michael

    Circulators are directional circuit elements integral to technologies including radar systems, microwave communication transceivers and the readout of quantum information devices. Their non-reciprocity commonly arises from the interference of microwaves over the centimetre-scale of the signal wavelength in the presence of bulky magnetic media that breaks time-reversal symmetry. We present a completely passive on-chip microwave circulator with size 1/1000th the wavelength by exploiting the chiral, `slow-light' response of a GaAs/AlGaAs 2-dimensional electron gas in the quantum Hall regime. Further, by implementing this circulator design on a thin film of a magnetic topological insulator (Cr0.12(Bi0.26Sb0.62)2Te3), we show that similar non-reciprocity can be achieved at zero magnetic field. This additional mode of operation serves as a non-invasive probe of edge states in the quantum anomalous Hall effect, while also extending the possibility for integration with superconducting devices.

  7. Development of a steady-state calculation model for the KALIMER PDRC(Passive Decay Heat Removal Circuit)

    International Nuclear Information System (INIS)

    Chang, Won Pyo; Ha, Kwi Seok; Jeong, Hae Yong; Kwon, Young Min; Eoh, Jae Hyuk; Lee, Yong Bum

    2003-06-01

    A sodium circuit has usually featured for a Liquid Metal Reactor(LMR) using sodium as coolant to remove the decay heat ultimately under accidental conditions because of its high reliability. Most of the system codes used for a Light Water Reactor(LWR) analysis is capable of calculating natural circulation within such circuit, but the code currently used for the LMR analysis does not feature stand alone capability to simulate the natural circulation flow inside the circuit due to its application limitation. To this end, the present study has been carried out because the natural circulation analysis for such the circuit is realistically raised for the design with a new concept. The steady state modeling is presented in this paper, development of a transient model is also followed to close the study. The incompressibility assumption of sodium which allow the circuit to be modeled with a single flow, makes the model greatly simplified. Models such as a heat exchanger developed in the study can be effectively applied to other system analysis codes which require such component models

  8. The voltage—current relationship and equivalent circuit implementation of parallel flux-controlled memristive circuits

    International Nuclear Information System (INIS)

    Bao Bo-Cheng; Feng Fei; Dong Wei; Pan Sai-Hu

    2013-01-01

    A flux-controlled memristor characterized by smooth cubic nonlinearity is taken as an example, upon which the voltage—current relationships (VCRs) between two parallel memristive circuits — a parallel memristor and capacitor circuit (the parallel MC circuit), and a parallel memristor and inductor circuit (the parallel ML circuit) — are investigated. The results indicate that the VCR between these two parallel memristive circuits is closely related to the circuit parameters, and the frequency and amplitude of the sinusoidal voltage stimulus. An equivalent circuit model of the memristor is built, upon which the circuit simulations and experimental measurements of both the parallel MC circuit and the parallel ML circuit are performed, and the results verify the theoretical analysis results

  9. Fabric circuits and method of manufacturing fabric circuits

    Science.gov (United States)

    Chu, Andrew W. (Inventor); Dobbins, Justin A. (Inventor); Scully, Robert C. (Inventor); Trevino, Robert C. (Inventor); Lin, Greg Y. (Inventor); Fink, Patrick W. (Inventor)

    2011-01-01

    A flexible, fabric-based circuit comprises a non-conductive flexible layer of fabric and a conductive flexible layer of fabric adjacent thereto. A non-conductive thread, an adhesive, and/or other means may be used for attaching the conductive layer to the non-conductive layer. In some embodiments, the layers are attached by a computer-driven embroidery machine at pre-determined portions or locations in accordance with a pre-determined attachment layout before automated cutting. In some other embodiments, an automated milling machine or a computer-driven laser using a pre-designed circuit trace as a template cuts the conductive layer so as to separate an undesired portion of the conductive layer from a desired portion of the conductive layer. Additional layers of conductive fabric may be attached in some embodiments to form a multi-layer construct.

  10. Thermohaline circulation in the Gulf of California

    Science.gov (United States)

    Bray, N. A.

    1988-05-01

    The Gulf of California, a narrow, semienclosed sea, is the only evaporative basin of the Pacific Ocean. As a result of evaporative forcing, salinities in the gulf are 1 to 2 ‰ higher than in the adjacent Pacific at the same latitude. This paper examines the thermohaline structure of the gulf and the means by which thermohaline exchange between the Pacific and the gulf occurs, over time scales of months to years. In addition to evaporative forcing, air-sea heat fluxes and momentum fluxes are important to thermohaline circulation in the gulf. From observations presented here, it appears that the gulf gains heat from the atmosphere on an annual average, unlike the Mediterranean and Red seas, which have comparable evaporative forcing. As a result, outflow from the gulf tends to be less dense than inflow from the Pacific. Winds over the gulf change direction with season, blowing northward in summer and southward in winter. This same seasonal pattern appears in near-surface transports averaged across the gulf. The thermohaline circulation, then, consists of outflow mostly between about 50 m and 250 m, inflow mostly between 250 m and 500 m, and a surface layer in which the direction of transport changes with seasonal changes in the large-scale winds. Using hydrographic observations from a section across the central gulf, total transport in or out of the northern gulf is estimated to be 0.9 Sv, heat gain from the atmosphere is estimated to be 20 to 50 W m-2, and evaporation is estimated to be 0.95 m yr-1. These estimates are annual averages, based on cruises from several years. Seasonal variations in thermohaline structure in the gulf are also examined and found to dominate the variance in temperature and density in the top 500 m of the water column. Salinity has little seasonal variability but does exhibit more horizontal variablility than temperature or density. Major year-to-year variations in thermohaline structure may be attributable to El Niño-Southern Oscillation

  11. Investigation of Equivalent Circuit for PEMFC Assessment

    International Nuclear Information System (INIS)

    Myong, Kwang Jae

    2011-01-01

    Chemical reactions occurring in a PEMFC are dominated by the physical conditions and interface properties, and the reactions are expressed in terms of impedance. The performance of a PEMFC can be simply diagnosed by examining the impedance because impedance characteristics can be expressed by an equivalent electrical circuit. In this study, the characteristics of a PEMFC are assessed using the AC impedance and various equivalent circuits such as a simple equivalent circuit, equivalent circuit with a CPE, equivalent circuit with two RCs, and equivalent circuit with two CPEs. It was found in this study that the characteristics of a PEMFC could be assessed using impedance and an equivalent circuit, and the accuracy was highest for an equivalent circuit with two CPEs

  12. Sustainability issues in circuit board recycling

    DEFF Research Database (Denmark)

    Legarth, Jens Brøbech; Alting, Leo; Baldo, Gian Luca

    1995-01-01

    The resource recovery and environmental impact issues of printed circuit board recycling by secondary copper smelters are discussed. Guidelines concerning material selection for circuit board manufacture and concerning the recycling processes are given to enhance recovery efficiency and to lower...

  13. Developing a Domain Model for Relay Circuits

    DEFF Research Database (Denmark)

    Haxthausen, Anne Elisabeth

    2009-01-01

    In this paper we stepwise develop a domain model for relay circuits as used in railway control systems. First we provide an abstract, property-oriented model of networks consisting of components that can be glued together with connectors. This model is strongly inspired by a network model...... for railways madeby Bjørner et.al., however our model is more general: the components can be of any kind and can later be refined to e.g. railway components or circuit components. Then we show how the abstract network model can be refined into an explicit model for relay circuits. The circuit model describes...... the statics as well as the dynamics of relay circuits, i.e. how a relay circuit can be composed legally from electrical components as well as how the components may change state over time. Finally the circuit model is transformed into an executable model, and we show how a concrete circuit can be defined...

  14. Telecommunications Circuit Allocation Programs - Kansas City Area

    National Research Council Canada - National Science Library

    Thomas, William

    1994-01-01

    The overall objective of the audit was to determine whether DoD circuit allocation programs identified and used the most effective configurations for leased long-haul, special-purpose telecommunications circuits...

  15. Circuit QED lattices: Towards quantum simulation with superconducting circuits

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Sebastian [Institute for Theoretical Physics, ETH Zurich, 8093, Zurich (Switzerland); Koch, Jens [Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208 (United States)

    2013-06-15

    The Jaynes-Cummings model describes the coupling between photons and a single two-level atom in a simplified representation of light-matter interactions. In circuit QED, this model is implemented by combining microwave resonators and superconducting qubits on a microchip with unprecedented experimental control. Arranging qubits and resonators in the form of a lattice realizes a new kind of Hubbard model, the Jaynes-Cummings-Hubbard model, in which the elementary excitations are polariton quasi-particles. Due to the genuine openness of photonic systems, circuit QED lattices offer the possibility to study the intricate interplay of collective behavior, strong correlations and non-equilibrium physics. Thus, turning circuit QED into an architecture for quantum simulation, i.e., using a well-controlled system to mimic the intricate quantum behavior of another system too daunting for a theorist to tackle head-on, is an exciting idea which has served as theorists' playground for a while and is now also starting to catch on in experiments. This review gives a summary of the most recent theoretical proposals and experimental efforts. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. VanderLaan Circulant Type Matrices

    Directory of Open Access Journals (Sweden)

    Hongyan Pan

    2015-01-01

    Full Text Available Circulant matrices have become a satisfactory tools in control methods for modern complex systems. In the paper, VanderLaan circulant type matrices are presented, which include VanderLaan circulant, left circulant, and g-circulant matrices. The nonsingularity of these special matrices is discussed by the surprising properties of VanderLaan numbers. The exact determinants of VanderLaan circulant type matrices are given by structuring transformation matrices, determinants of well-known tridiagonal matrices, and tridiagonal-like matrices. The explicit inverse matrices of these special matrices are obtained by structuring transformation matrices, inverses of known tridiagonal matrices, and quasi-tridiagonal matrices. Three kinds of norms and lower bound for the spread of VanderLaan circulant and left circulant matrix are given separately. And we gain the spectral norm of VanderLaan g-circulant matrix.

  17. Experimental analysis of the natural circulation phenomenon at the monophase system

    International Nuclear Information System (INIS)

    Santos, Thiago A. dos; Stefanni, Giovanni Laranjo de; Conti, Thadeu das Neves

    2011-01-01

    The present work study the phenomenology of the natural circulation, which is the flow circulation without help of any mechanical device. One of the possible application of this study would be a new way of nuclear reactor cooling, and this practice is fundamental for the maintenance and safe of the reactor. For this study, a therma balance in the circuit was performed, which consist of evaluate the behavior of the circuit, observing if not exist excessive energy loss. The balance was made only for power values considered small (up to 4000 W), were the fluid is at the monophasic state. This methodology is extremely important for the evaluation of the equipment and determining therefore if the energy is conserved in order to work with a more complex system such as the two-phase one

  18. Global Current Circuit Structure in a Resistive Pulsar Magnetosphere Model

    Science.gov (United States)

    Kato, Yugo. E.

    2017-12-01

    Pulsar magnetospheres have strong magnetic fields and large amounts of plasma. The structures of these magnetospheres are studied using force-free electrodynamics. To understand pulsar magnetospheres, discussions must include their outer region. However, force-free electrodynamics is limited in it does not handle dissipation. Therefore, a resistive pulsar magnetic field model is needed. To break the ideal magnetohydrodynamic (MHD) condition E\\cdot B=0, Ohm’s law is used. This work introduces resistivity depending upon the distance from the star and obtain a self-consistent steady state by time integration. Poloidal current circuits form in the magnetosphere while the toroidal magnetic field region expands beyond the light cylinder and the Poynting flux radiation appears. High electric resistivity causes a large space scale poloidal current circuit and the magnetosphere radiates a larger Poynting flux than the linear increase outside of the light cylinder radius. The formed poloidal-current circuit has width, which grows with the electric conductivity. This result contributes to a more concrete dissipative pulsar magnetosphere model.

  19. Nuclear forces

    International Nuclear Information System (INIS)

    Holinde, K.

    1990-01-01

    In this paper the present status of the meson theory of nuclear forces is reviewed. After some introductory remarks about the relevance of the meson exchange concept in the era of QCD and the empirical features of the NN interaction, the exciting history of nuclear forces is briefly outlined. In the main part, the author gives the basic physical ideas and sketch the derivation of the one-boson-exchange model of the nuclear force, in the Feynman approach. Secondly we describe, in a qualitative way, various necessary extensions, leading to the Bonn model of the N interaction. Finally, points to some interesting pen questions connected with the extended quark structure of the hadrons, which are topics of current research activity

  20. What's new about generator circuit breakers

    International Nuclear Information System (INIS)

    Kolarik, P.L.

    1979-01-01

    The need for updating ANSI C37 Standards for AC high-voltage circuit breakers has become necessary because of the increased interest in power circuit breakers for generator application. These circuit breakers, which have continuous current ratings and rated short-circuit currents that are much higher than those presently covered by existing C37 Standards, take on added importance because they are being installed in critical AC power supplies at nuclear power stations

  1. Trip electrical circuit of the gyrotion

    International Nuclear Information System (INIS)

    Rossi, J.O.

    1987-09-01

    The electron cyclotron resonance heating system of INPE/LAP is shown and the trip electrical circuit of the gyrotron is described, together with its fundamental aspects. The trip electrical circuit consists basically of a series regulator circuit which regulates the output voltage level and controls the pulse width time. Besides that, a protection circuit for both tubes, regulator and gyrotron, against faults in the system. (author) [pt

  2. Hybdrid integral circuit for proportional chambers

    International Nuclear Information System (INIS)

    Yanik, R.; Khudy, M.; Povinets, P.; Strmen', P.; Grabachek, Z.; Feshchenko, A.A.

    1978-01-01

    Outlined briefly are a hybrid integrated circuit of the channel. One channel contains an input amplifier, delay circuit, and memory register on the base of the D-type flip-flop and controlled by the recording gate pulse. Provided at the output of the channel is a readout gating circuit. Presented are the flowsheet of the channel, the shaper amplifier and logical channel. At present the logical circuit was accepted for manufacture

  3. A Fault Tolerant Integrated Circuit Memory

    OpenAIRE

    Barton, Anthony Francis

    1980-01-01

    Most commercially produced integrated circuits are incapable of tolerating manufacturing defects. The area and function of the circuits is thus limited by the probability of faults occurring within the circuit. This thesis examines techniques for using redundancy in memory circuits to provide fault tolerance and to increase storage capacity. A hierarchical memory architecture using multiple Hamming codes is introduced and analysed to determine its resistance to manufa...

  4. Analysis of the flow imbalance in the KSTAR PF cryo-circuit

    International Nuclear Information System (INIS)

    Lee, Hyun-Jung; Park, Dong-Seong; Kwag, Sang-Woo; Joo, Jae-Jun; Moon, Kyung-Mo; Kim, Nam-Won; Lee, Young-Joo; Park, Young-Min; Yang, Hyung-Lyeol

    2015-01-01

    Highlights: • Investigate of flow imbalance trend for the KSTAR PF superconducting magnet. • Flow imbalance is compared with individual magnet test and integration magnet test. • Intensifying of flow imbalance is proven from the flow monitoring in the KSTAR PF circuit. • Flow behavior is analyzed during magnet charging in the circulator circuit. • Variation of magnet outlet temperature is analyzed due to flow imbalance. - Abstract: The KSTAR PF cryo-circuit is a quasi-closed circulation system in which more than 370 g/s of supercritical helium (SHe) is circulated using a SHe circulator. The heated helium from superconducting magnet is cooled through sub cooler (4.3 K). The circulator is operated at 4.5 K and 6.5 bar, and the pressure drop of the circuit is kept at 2 bar in order to maintain the supercritical state and circulator stability. The circuit is connected with helium refrigerator system, distribution system, and supercritical magnet system. It has a hundred branches to supply supercritical helium to the poloidal field superconducting magnet. The branch was designed to optimize the operation conditions and they are grouped for one cryogenic valve has the same length within the cardinal principle of the optimization. Five cryogenic valves are installed to control the mass flow rate, and seven orifice mass flow meters, differential pressure gauges and temperature sensors were installed in front of the magnet in the distribution because upper magnet and lower magnet is symmetric theoretically. The cryogenic pipe line was manufactured with elevation about 10 m between upper magnet and lower magnet. The inlet and outlet helium feed-through were installed at the coil inside in case of KSTAR PF1–PF5 upper magnet and lower magnet. The flow imbalance is caused by void fraction and it could be changed due to manufacturing process even if it has the same length of cooling channel. This creates an imbalance among cooling channels and temperatures are

  5. Development of a pulse shape discrimination circuit

    International Nuclear Information System (INIS)

    Ye Bangjiao; Fan Wei; Fan Yangmei; Yu Xiaoqi; Mei Wen; Wang Zhongmin; Han Rongdian; Xiao Zhenxi

    1994-01-01

    A pulse shape discrimination circuit was designed and used in an experiment measuring double-differential cross sections of (n, charged particle) reaction; to identify p, α and γ. The performance of the circuit was tested. With this circuit, excellent identification of p, α and γ was obtained. ((orig.))

  6. Circuit card failures and industry mitigation strategy

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, U. [Candu Owners Group, Toronto, Ontario (Canada)

    2012-07-01

    In recent years the nuclear industry has experienced an increase in circuit card failures due to ageing of components, inadequate Preventive Maintenance (PM), lack of effective circuit card health monitoring, etc. Circuit card failures have caused loss of critical equipment, e.g., electro hydraulic governors, Safety Systems, resulting in loss of function and in some cases loss of generation. INPO completed a root cause analysis of 40 Reactor Trips/Scrams in US reactors and has recommended several actions to mitigate Circuit Card failures. Obsolescence of discrete components has posed many challenges in conducting effective preventative maintenance on circuit cards. In many cases, repairs have resulted in installation of components that compromise performance of the circuit cards. Improper termination and worn edge connectors have caused intermittent contacts contributing to circuit card failures. Traditionally, little attention is paid to relay functions and preventative maintenance of relay. Relays contribute significantly to circuit card failures and have dominated loss of generation across the power industry. The INPO study recommended a number of actions to mitigate circuit card failures, such as; identification of critical components and single point vulnerabilities; strategic preventative maintenance; protection of circuit boards against electrostatic discharge; limiting power cycles; performing an effective burn-in prior to commissioning of the circuit cards; monitoring performance of DC power supplies; limiting cabinet temperatures; managing of component aging/degradation mechanism, etc. A subcommittee has been set up under INPO sponsorship to understand the causes of circuit card failure and to develop an effective mitigation strategy. (author)

  7. Improvements in or relating to transistor circuits

    International Nuclear Information System (INIS)

    Richards, R.F.; Williamson, P.W.

    1978-01-01

    This invention relates to transistor circuits and in particular to integrated transistor circuits formed on a substrate of semi-conductor material such as silicon. The invention is concerned with providing integrated circuits in which malfunctions caused by the effects of ionising, e.g. nuclear, radiations are reduced. (author)

  8. CMOS digital integrated circuits a first course

    CERN Document Server

    Hawkins, Charles; Zarkesh-Ha, Payman

    2016-01-01

    This book teaches the fundamentals of modern CMOS technology and covers equal treatment to both types of MOSFET transistors that make up computer circuits; power properties of logic circuits; physical and electrical properties of metals; introduction of timing circuit electronics and introduction of layout; real-world examples and problem sets.

  9. Piezo pump and pressurized circuit provided therewith

    NARCIS (Netherlands)

    Van Es, Johannes; Wits, Wessel Willems

    2015-01-01

    A piezo pump for use in a pressurized circuit includes a pump chamber with an inlet provided with a one way inlet valve, for connection to a feeding line of the pressurized circuit and an outlet provided with a one way outlet valve, for connection to a discharge line of the pressurized circuit and a

  10. 49 CFR 236.721 - Circuit, control.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Circuit, control. 236.721 Section 236.721..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.721 Circuit, control. An electrical circuit between a source of electric energy and a device which it operates. ...

  11. Sensing And Force-Reflecting Exoskeleton

    Science.gov (United States)

    Eberman, Brian; Fontana, Richard; Marcus, Beth

    1993-01-01

    Sensing and force-reflecting exoskeleton (SAFiRE) provides control signals to robot hand and force feedback from robot hand to human operator. Operator makes robot hand touch objects gently and manipulates them finely without exerting excessive forces. Device attaches to operator's hand; comfortable and lightweight. Includes finger exoskeleton, cable mechanical transmission, two dc servomotors, partial thumb exoskeleton, harness, amplifier box, two computer circuit boards, and software. Transduces motion of index finger and thumb. Video monitor of associated computer displays image corresponding to motion.

  12. Steady state flow analysis of two-phase natural circulation in multiple parallel channel loop

    International Nuclear Information System (INIS)

    Bhusare, V.H.; Bagul, R.K.; Joshi, J.B.; Nayak, A.K.; Kannan, Umasankari; Pilkhwal, D.S.; Vijayan, P.K.

    2016-01-01

    Highlights: • Liquid circulation velocity increases with increasing superficial gas velocity. • Total two-phase pressure drop decreases with increasing superficial gas velocity. • Channels with larger driving force have maximum circulation velocities. • Good agreement between experimental and model predictions. - Abstract: In this work, steady state flow analysis has been carried out experimentally in order to estimate the liquid circulation velocities and two-phase pressure drop in air–water multichannel circulating loop. Experiments were performed in 15 channel circulating loop. Single phase and two-phase pressure drops in the channels have been measured experimentally and have been compared with theoretical model of Joshi et al. (1990). Experimental measurements show good agreement with model.

  13. Investigations on the thermal-hydraulics of a natural circulation cooled BWR fuel assembly

    Energy Technology Data Exchange (ETDEWEB)

    Kok, H.V.; Hagen, T.H.J.J. van der; Mudde, R.F. [Delft Univ. of Technology (Netherlands)

    1995-09-01

    A scaled natural circulation loop facility has been built after the Dodewaard Boiling Water Reactor, which is the only operating natural circulation cooled BWR in the world. The loop comprises one fuel assembly, a riser with a downcomer and a condenser with a cooling system. Freon-12 is used as a scaling liquid. This paper reports on the first measurements done with this facility. Quantities like the circulation flow, carry-under and the void-fraction have been measured as a function of power, pressure, liquid level, riser length, condensate temperature and friction factors. The behavior of the circulation flow can be understood by considering the driving force. Special attention has been paid to the carry-under, which has been shown to have a very important impact on the dynamics of a natural circulation cooled BWR.

  14. The role of natural circulation in the FFTF [Fast Flux Test Facility] passive safety tests

    International Nuclear Information System (INIS)

    Stover, R.L.; Padilla, A.; Burke, T.M.; Knecht, W.L.

    1987-03-01

    A series of tests were completed at the Fast Flux Test Facility to demonstrate the passive safety characteristics of liquid metal reactors with natural circulation flow. The first test consisted of transition from forced to natural circulation flow at an initial decay power of 0.3%. The second test represented an unprotected loss-of-flow transient to natural circulation from 50% power with the control rods prevented from scramming into the core. The third test was a steady-state, natural circulation condition with core fission powers up ato about 2.3%. Core sodium data and results of single and multi-channel computer models confirmed the reliability and effectiveness of natural circulation flow for liquid metal reactor safety

  15. Superconducting flux flow digital circuits

    International Nuclear Information System (INIS)

    Martens, J.S.; Zipperian, T.E.; Hietala, V.M.; Ginley, D.S.; Tigges, C.P.; Phillips, J.M.; Siegal, M.P.

    1993-01-01

    The authors have developed a family of digital logic circuits based on superconducting flux flow transistors that show high speed, reasonable signal levels, large fan-out, and large noise margins. The circuits are made from high-temperature superconductors (HTS) and have been shown to operate at over 90 K. NOR gates have been demonstrated with fan-outs of more than 5 and fully loaded switching times less than a fixture-limited 50 ps. Ring-oscillator data suggest inverter delay times of about 40ps when using a 3-μm linewidths. Simple flip-flops have also been demonstrated showing large noise margins, response times of less than 30 ps, and static power dissipation on the order of 30 nW. Among other uses, this logic family is appropriate as an interface between logic families such as single flux quantum and conventional semiconductor logic

  16. Advanced Microwave Circuits and Systems

    DEFF Research Database (Denmark)

    This book is based on recent research work conducted by the authors dealing with the design and development of active and passive microwave components, integrated circuits and systems. It is divided into seven parts. In the first part comprising the first two chapters, alternative concepts...... amplifier architectures. In addition, distortion analysis and power combining techniques are considered. Another key element in most microwave systems is a signal generator. It forms the heart of all kinds of communication and radar systems. The fourth part of this book is dedicated to signal generators...... push currently available technologies to the limits. Some considerations to meet the growing requirements are provided in the fifth part of this book. The following part deals with circuits based on LTCC and MEMS technologies. The book concludes with chapters considering application of microwaves...

  17. Electron commutator on integrated circuits

    International Nuclear Information System (INIS)

    Demidenko, V.V.

    1975-01-01

    The scheme and the parameters of an electron 16-channel contactless commutator based entirely on integrated circuits are described. The device consists of a unit of analog keys based on field-controlled metal-insulator-semiconductor (m.i.s.) transistors, operation amplifier comparators controlling these keys, and a level distributor. The distributor is based on a ''matrix'' scheme and comprises two ring-shaped shift registers plugged in series and a decoder base on two-input logical elements I-NE. The principal dynamical parameters of the circuit are as follows: the control signal delay in the distributor. 50 nsec; the total channel switch-over time, 500-600 nsec. The commutator transmits both constant signals and pulses whose duration reaches tens of nsec. The commutator can be used in data acquisition and processing systems, for shaping complicated signals (for example), (otherwise signals), for simultaneous oscillographing of several signals, and so forth [ru

  18. 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.

  19. Foundations for microstrip circuit design

    CERN Document Server

    Edwards, Terry

    2016-01-01

    Building on the success of the previous three editions, Foundations for Microstrip Circuit Design offers extensive new, updated and revised material based upon the latest research. Strongly design-oriented, this fourth edition provides the reader with a fundamental understanding of this fast expanding field making it a definitive source for professional engineers and researchers and an indispensable reference for senior students in electronic engineering. Topics new to this edition: microwave substrates, multilayer transmission line structures, modern EM tools and techniques, microstrip and planar transmision line design, transmission line theory, substrates for planar transmission lines, Vias, wirebonds, 3D integrated interposer structures, computer-aided design, microstrip and power-dependent effects, circuit models, microwave network analysis, microstrip passive elements, and slotline design fundamentals.

  20. Study on the phenomena of natural circulation in LMFBR

    International Nuclear Information System (INIS)

    Takeda, Hirofumi; Koga, Tomonari

    1993-01-01

    Decay heat removal with natural circulation is to be introduced to the LMFBR operation under loss of the electric power supply. The natural circulation is highly reliable, but the phenomenon is essentially unstable and subtle, which makes fine prediction difficult. The difficulties of experimental prediction are explained by facts that the phenomena are ruled by the delicate balance between the buoyancy force and the low pressure loss and are influenced by the various parameters such as local geometry, heat capacity and so on. Therefore the similarity rule for the natural circulation has not been fully understood. This study has been conducted to establish the simulation method for the natural circulation phenomena and the detailed phenomena have been reviewed. For the natural circulation in an LMFBR plant, there are no readily available reference velocity and temperature. These values are related only with the heating and cooling rate, the characteristic length and physical properties of the testing fluid. Basic equations were transformed by these values, and dimensionless equations were derived and then two dimensionless numbers, the Gr' number and the Bo' number, were identified. In order to examine the similarity rule for natural circulation we performed experiments using the different scale water models, a 1/20th and a 1/6th model. The temperatures and velocities at typical points were measured in the transient condition with various heating rate as a parameter. Measured temperatures and velocities were transformed to dimensionless forms for comparison and the effects of the Bo' number and the Gr' number were examined. As a result, it was clarified that the effect of the Gr' number is negligibly small but the effect of Bo' number still remained in our experimental range. The Bo' number of an actual plant is within the range of this experiment. Accordingly similitude of the Bo' number becomes important in an experiment to simulate an actual plant. (author)

  1. Unbalanced neuronal circuits in addiction.

    Science.gov (United States)

    Volkow, Nora D; Wang, Gen-Jack; Tomasi, Dardo; Baler, Ruben D

    2013-08-01

    Through sequential waves of drug-induced neurochemical stimulation, addiction co-opts the brain's neuronal circuits that mediate reward, motivation to behavioral inflexibility and a severe disruption of self-control and compulsive drug intake. Brain imaging technologies have allowed neuroscientists to map out the neural landscape of addiction in the human brain and to understand how drugs modify it. Published by Elsevier Ltd.

  2. Monolithic readout circuits for RHIC

    International Nuclear Information System (INIS)

    O'Connor, P.; Harder, J.; Sippach, W.

    1991-10-01

    Several CMOS ASICs have been developed for a proposed RHIC experiment. This paper discusses why ASIC implementation was chosen for certain functions, circuit specifications and the design techniques used to meet them, and results of simulations and early prototypes. By working closely together from an early stage in the planning process, in-house ASIC designers and detector and data acquisition experimenters can achieve optimal use of this important technology

  3. Circuit complexity of regular languages

    Czech Academy of Sciences Publication Activity Database

    Koucký, Michal

    2009-01-01

    Roč. 45, č. 4 (2009), s. 865-879 ISSN 1432-4350 R&D Projects: GA ČR GP201/07/P276; GA MŠk(CZ) 1M0545 Institutional research plan: CEZ:AV0Z10190503 Keywords : regular languages * circuit complexity * upper and lower bounds Subject RIV: BA - General Mathematics Impact factor: 0.726, year: 2009

  4. Realistic Realizations Of Threshold Circuits

    Science.gov (United States)

    Razavi, Hassan M.

    1987-08-01

    Threshold logic, in which each input is weighted, has many theoretical advantages over the standard gate realization, such as reducing the number of gates, interconnections, and power dissipation. However, because of the difficult synthesis procedure and complicated circuit implementation, their use in the design of digital systems is almost nonexistant. In this study, three methods of NMOS realizations are discussed, and their advantages and shortcomings are explored. Also, the possibility of using the methods to realize multi-valued logic is examined.

  5. Microcontroller based Integrated Circuit Tester

    OpenAIRE

    Yousif Taha Yousif Elamin; Abdelrasoul Jabar Alzubaidi

    2015-01-01

    The digital integrated circuit (IC) tester is implemented by using the ATmega32 microcontroller . The microcontroller processes the inputs and outputs and displays the results on a Liquid Crystal Display (LCD). The basic function of the digital IC tester is to test a digital IC for correct logical functioning as described in the truth table and/or function table. The designed model can test digital ICs having 14 pins. Since it is programmable, any number of ICs can be tested . Thi...

  6. Monolithic readout circuits for RHIC

    Energy Technology Data Exchange (ETDEWEB)

    O`Connor, P.; Harder, J. [Brookhaven National Laboratory, Upton, NY (United States)

    1991-12-31

    Several CMOS ASICs have been developed for a proposed RHIC experiment. This paper discusses why ASIC implementation was chosen for certain functions, circuit specifications and the design techniques used to meet them, and results of simulations and early prototypes. By working closely together from an early stage in the planning process, in-house ASIC designers and detector and data acquisition experimenters can achieve optimal use of this important technology.

  7. Root finding with threshold circuits

    Czech Academy of Sciences Publication Activity Database

    Jeřábek, Emil

    2012-01-01

    Roč. 462, Nov 30 (2012), s. 59-69 ISSN 0304-3975 R&D Projects: GA AV ČR IAA100190902; GA MŠk(CZ) 1M0545 Institutional support: RVO:67985840 Keywords : root finding * threshold circuit * power series Subject RIV: BA - General Mathematics Impact factor: 0.489, year: 2012 http://www.sciencedirect.com/science/article/pii/S0304397512008006#

  8. Refractory silicides for integrated circuits

    International Nuclear Information System (INIS)

    Murarka, S.P.

    1980-01-01

    Transition metal silicides have, in the past, attracted attention because of their usefulness as high temperature materials and in integrated circuits as Schottky barrier and ohmic contacts. More recently, with the increasing silicon integrated circuits (SIC) packing density, the line widths get narrower and the sheet resistance contribution to the RC delay increases. The possibility of using low resistivity silicides, which can be formed directly on the polysilicon, makes these silicides highly attractive. The usefulness of a silicide metallization scheme for integrated circuits depends, not only on the desired low resistivity, but also on the ease with which the silicide can be formed and patterned and on the stability of the silicides throughout device processing and during actual device usage. In this paper, various properties and the formation techniques of the silicides have been reviewed. Correlations between the various properties and the metal or silicide electronic or crystallographic structure have been made to predict the more useful silicides for SIC applications. Special reference to the silicide resistivity, stress, and oxidizability during the formation and subsequent processing has been given. Various formation and etching techniques are discussed

  9. Ultra-low power integrated circuit design circuits, systems, and applications

    CERN Document Server

    Li, Dongmei; Wang, Zhihua

    2014-01-01

    This book describes the design of CMOS circuits for ultra-low power consumption including analog, radio frequency (RF), and digital signal processing circuits (DSP). The book addresses issues from circuit and system design to production design, and applies the ultra-low power circuits described to systems for digital hearing aids and capsule endoscope devices. Provides a valuable introduction to ultra-low power circuit design, aimed at practicing design engineers; Describes all key building blocks of ultra-low power circuits, from a systems perspective; Applies circuits and systems described to real product examples such as hearing aids and capsule endoscopes.

  10. Early concepts and charts of ocean circulation

    Science.gov (United States)

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

    Charts of ocean currents from the late nineteenth century show that already by then the patterns of surface circulation in regions away from polar latitudes were well understood. This fundamental knowledge accumulated gradually through centuries of sea travel and had reached a state of near correctness by the time dedicated research cruises, full-depth measurements and the practical application of the dynamical method were being instituted. Perhaps because of the foregoing, many of the pioneering works, critical to establishing what the upper-level circulation is like, the majority of the charts accompanying them, and several of the groundbreaking theoretical treatments on the physics of currents, are only poorly known to present-day oceanographers. In this paper we trace Western developments in knowledge and understanding of ocean circulation from the earliest times to the late-1800s transition into the modern era. We also discuss certain peripheral advances that proved critical to the subject. The earliest known ideas, dating from the Bronze Age and described by Homer, necessarily reflect severe limitations to geographical knowledge, as well as basic human predilections toward conjecture and exaggeration in the face of inadequate information. People considered the earth to be flat and circular, with the ocean flowing like a river around it. They also believed in horrific whirlpools, a concept that persisted into the Renaissance and which would later provide subject material for modern literature. From the Greek Classical Age, we find hydrologic theories of Earth's interior being laced with subterranean channels (Socrates) and all motion deriving from a divine force forever propelling the heavens toward the west, the primum mobile (Aristotle). These ideas, particularly the latter, dominated opinions about ocean circulation into the late Renaissance. By late Antiquity mariners had very likely acquired intimate knowledge of coastal currents in the Mediterranean, but

  11. CMOS circuit design, layout and simulation

    CERN Document Server

    Baker, R Jacob

    2010-01-01

    The Third Edition of CMOS Circuit Design, Layout, and Simulation continues to cover the practical design of both analog and digital integrated circuits, offering a vital, contemporary view of a wide range of analog/digital circuit blocks including: phase-locked-loops, delta-sigma sensing circuits, voltage/current references, op-amps, the design of data converters, and much more. Regardless of one's integrated circuit (IC) design skill level, this book allows readers to experience both the theory behind, and the hands-on implementation of, complementary metal oxide semiconductor (CMOS) IC design via detailed derivations, discussions, and hundreds of design, layout, and simulation examples.

  12. Design of analog integrated circuits and systems

    CERN Document Server

    Laker, Kenneth R

    1994-01-01

    This text is designed for senior or graduate level courses in analog integrated circuits or design of analog integrated circuits. This book combines consideration of CMOS and bipolar circuits into a unified treatment. Also included are CMOS-bipolar circuits made possible by BiCMOS technology. The text progresses from MOS and bipolar device modelling to simple one and two transistor building block circuits. The final two chapters present a unified coverage of sample-data and continuous-time signal processing systems.

  13. Variable cooling circuit for thermoelectric generator and engine and method of control

    Science.gov (United States)

    Prior, Gregory P

    2012-10-30

    An apparatus is provided that includes an engine, an exhaust system, and a thermoelectric generator (TEG) operatively connected to the exhaust system and configured to allow exhaust gas flow therethrough. A first radiator is operatively connected to the engine. An openable and closable engine valve is configured to open to permit coolant to circulate through the engine and the first radiator when coolant temperature is greater than a predetermined minimum coolant temperature. A first and a second valve are controllable to route cooling fluid from the TEG to the engine through coolant passages under a first set of operating conditions to establish a first cooling circuit, and from the TEG to a second radiator through at least some other coolant passages under a second set of operating conditions to establish a second cooling circuit. A method of controlling a cooling circuit is also provided.

  14. Graphene radio frequency receiver integrated circuit.

    Science.gov (United States)

    Han, Shu-Jen; Garcia, Alberto Valdes; Oida, Satoshi; Jenkins, Keith A; Haensch, Wilfried

    2014-01-01

    Graphene has attracted much interest as a future channel material in radio frequency electronics because of its superior electrical properties. Fabrication of a graphene integrated circuit without significantly degrading transistor performance has proven to be challenging, posing one of the major bottlenecks to compete with existing technologies. Here we present a fabrication method fully preserving graphene transistor quality, demonstrated with the implementation of a high-performance three-stage graphene integrated circuit. The circuit operates as a radio frequency receiver performing signal amplification, filtering and downconversion mixing. All circuit components are integrated into 0.6 mm(2) area and fabricated on 200 mm silicon wafers, showing the unprecedented graphene circuit complexity and silicon complementary metal-oxide-semiconductor process compatibility. The demonstrated circuit performance allow us to use graphene integrated circuit to perform practical wireless communication functions, receiving and restoring digital text transmitted on a 4.3-GHz carrier signal.

  15. Journalism as Cultures of Circulation

    DEFF Research Database (Denmark)

    Bødker, Henrik

    2013-01-01

    The universe of journalism has always consisted of interspersed texts, meanings and practices. Yet, much journalism research has often isolated either texts and/or contexts and as such assumed relations between professional practices, informed (rational) readers and (conceived) core texts...... of journalism. It is, however, more important than ever to shift attention away from texts to the processes through which they are circulated. This is partly because the many cultural forms of journalism (textual, institutional, technological, material, behavioural and imagined) are undergoing significant......, likes, comments, searches, journalist roles, writing and reading positions and identities etc. Such forms will be traced within the mediation of a specific event with the overall aim of beginning a theorization of the landscape of journalism as highly interrelated cultures of circulation....

  16. Radioisotopic evaluation of portal circulation

    International Nuclear Information System (INIS)

    Maliska, C.; Rosenthal, D.

    1986-01-01

    The use of a radio-tracer of portal circulation through the intestine, should prevent cruel punctures in the portal-vein or spleen as it is usually the case with traditional methods in the study of portal-system. The absorption of I-131 and Tc-99m, previously cheked in rabbits presented similar results in dogs. The time of circulation between terminal large-intestine and the liver (t-RF) was determined by external counting at hepatic level by recording radioactivity variation-time. In healthy animals the t-RF was from 20to 60 seconds, with average time of 42 seconds. In 2 animals with partial binding of portal-vein the t-RF went up to 110 and 120 seconds. (Author) [pt

  17. Ocean circulation generated magnetic signals

    DEFF Research Database (Denmark)

    Manoj, C.; Kuvshinov, A.; Maus, S.

    2006-01-01

    Conducting ocean water, as it flows through the Earth's magnetic field, generates secondary electric and magnetic fields. An assessment of the ocean-generated magnetic fields and their detectability may be of importance for geomagnetism and oceanography. Motivated by the clear identification...... of ocean tidal signatures in the CHAMP magnetic field data we estimate the ocean magnetic signals of steady flow using a global 3-D EM numerical solution. The required velocity data are from the ECCO ocean circulation experiment and alternatively from the OCCAM model for higher resolution. We assume...... of the magnetic field, as compared to the ECCO simulation. Besides the expected signatures of the global circulation patterns, we find significant seasonal variability of ocean magnetic signals in the Indian and Western Pacific Oceans. Compared to seasonal variation, interannual variations produce weaker signals....

  18. Observations of Local Seychelles Circulation

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Observations of Local Seychelles Circulation Geno...goal for the proposed work is to develop predictive capabilities for physical oceanography for the Seychelles region in support of locally relevant...observations in the Seychelles region that will lead to long-term data collection efforts. In collaboration with local partnerships, we will carry out

  19. Circulating nucleic acids and evolution.

    Science.gov (United States)

    Anker, Philippe; Stroun, Maurice

    2012-06-01

    J.B. Lamarck in 1809 was the first to present a theory of evolution. He proposed it was due to the adaptation of species to environmental changes, this adaptation being acquired by the offspring. In 1868, Darwin suggested that cells excrete gemmules, which circulate through the body and reach the gonads where they are transmitted to the next generation. His main argument came from graft hybrids. In the fifties and sixties, Russian geneticists, rejecting neo-Darwinism, said that acquired characteristics were the basis of evolution. The main experiments on which they based their theory were the transmission of hereditary characteristics by a special technique of grafting between two varieties of plants. We repeated this kind of experiment and also succeeded in obtaining hereditary modifications of the pupil plants that acquired some characteristics of the mentor variety. Rather than adopting the views of the Russian scientists, we suggested that DNA was circulating between the mentor and pupil plants. Hirata's group have shown recently, by using molecular techniques such as cloning, RFLP PCR and sequencing some genes of their graft hybrids of pepper plants, that transfer of informative molecules from the mentor to the pupil plant does exist. Nucleic acids are actively released by cells; they circulate in the body. They can transform oncogenically or trigger antibody response but the only genetic transformation showing that DNA can go from the soma to the germen comes from graft hybrids. This suggests that circulating nucleic acids, in this case DNA, like Darwin's gemmules, play a role in the mechanism of evolution.

  20. Improvement of Classification of Enterprise Circulating Funds

    OpenAIRE

    Rohanova Hanna O.

    2014-01-01

    The goal of the article lies in revelation of possibilities of increase of efficiency of managing enterprise circulating funds by means of improvement of their classification features. Having analysed approaches of many economists to classification of enterprise circulating funds, systemised and supplementing them, the article offers grouping classification features of enterprise circulating funds. In the result of the study the article offers an expanded classification of circulating funds, ...

  1. Hall Effect Gyrators and Circulators

    Science.gov (United States)

    Viola, Giovanni; DiVincenzo, David P.

    2014-04-01

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

  2. Analysis of reverse flow in inverted U-tubes of steam generator under natural circulation condition

    International Nuclear Information System (INIS)

    Yang Ruichang; Liu Ruolei; Liu Jinggong; Qin Shiwei

    2008-01-01

    In this paper, we report on the analysis of reverse flow in inverted U-tubes of a steam generator under natural circulation condition. The mechanism of reverse flow in inverted U-tubes of the steam generator with natural circulation is graphically analyzed by using the full-range characteristic curve of parallel U-tubes. The mathematical model and numerical calculation method for analyzing the reverse flow in inverted U-tubes of the steam generator with natural circulation have been developed. The reverse flow in an inverted U-tube steam generator of a simulated pressurized water reactor with natural circulation in analyzed. Through the calculation, the mass flow rates of normal and reverse flows in individual U-tubes are obtained. The predicted sharp drop of the fluid temperature in the inlet plenum of the steam generator due to reverse flow agrees very well with the experimental data. This indicates that the developed mathematical model and solution method can be used to correctly predict the reverse flow in the inverted U-tubes of the steam generator with natural circulation. The obtained results also show that in the analysis of natural circulation flow in the primary circuit, the reverse flow in the inverted U-tubes of the steam generator must be taken into account. (author)

  3. Performance of an on-chip superconducting circulator for quantum microwave systems

    Science.gov (United States)

    Chapman, Benjamin; Rosenthal, Eric; Moores, Bradley; Kerckhoff, Joseph; Mates, J. A. B.; Hilton, G. C.; Vale, L. R.; Ullom, J. N.; LalumíEre, Kevin; Blais, Alexandre; Lehnert, K. W.

    Microwave circulators enforce a single propagation direction for signals in an electrical network. Unfortunately, commercial circulators are bulky, lossy, and cannot be integrated close to superconducting circuits because they require strong ( kOe) magnetic fields produced by permanent magnets. Here we report on the performance of an on-chip, active circulator for superconducting microwave circuits, which uses no permanent magnets. Non-reciprocity is achieved by actively modulating reactive elements around 100 MHz, giving roughly a factor of 50 in the separation between signal and control frequencies, which facilitates filtering. The circulator's active components are dynamically tunable inductors constructed with arrays of dc-SQUIDs in series. Array inductance is tuned by varying the magnetic flux through the SQUIDs with fields weaker than 1 Oe. Although the instantaneous bandwidth of the device is narrow, the operation frequency is tunable between 4 and 8 GHz. This presentation will describe the device's theory of operation and compare its measured performance to design goals. This work is supported by the ARO under contract W911NF-14-1-0079 and the National Science Foundation under Grant Number 1125844.

  4. Encoders for block-circulant LDPC codes

    Science.gov (United States)

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

    2009-01-01

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

  5. A Parallel Genetic Algorithm for Automated Electronic Circuit Design

    Science.gov (United States)

    Long, Jason D.; Colombano, Silvano P.; Haith, Gary L.; Stassinopoulos, Dimitris

    2000-01-01

    Parallelized versions of genetic algorithms (GAs) are popular primarily for three reasons: the GA is an inherently parallel algorithm, typical GA applications are very compute intensive, and powerful computing platforms, especially Beowulf-style computing clusters, are becoming more affordable and easier to implement. In addition, the low communication bandwidth required allows the use of inexpensive networking hardware such as standard office ethernet. In this paper we describe a parallel GA and its use in automated high-level circuit design. Genetic algorithms are a type of trial-and-error search technique that are guided by principles of Darwinian evolution. Just as the genetic material of two living organisms can intermix to produce offspring that are better adapted to their environment, GAs expose genetic material, frequently strings of 1s and Os, to the forces of artificial evolution: selection, mutation, recombination, etc. GAs start with a pool of randomly-generated candidate solutions which are then tested and scored with respect to their utility. Solutions are then bred by probabilistically selecting high quality parents and recombining their genetic representations to produce offspring solutions. Offspring are typically subjected to a small amount of random mutation. After a pool of offspring is produced, this process iterates until a satisfactory solution is found or an iteration limit is reached. Genetic algorithms have been applied to a wide variety of problems in many fields, including chemistry, biology, and many engineering disciplines. There are many styles of parallelism used in implementing parallel GAs. One such method is called the master-slave or processor farm approach. In this technique, slave nodes are used solely to compute fitness evaluations (the most time consuming part). The master processor collects fitness scores from the nodes and performs the genetic operators (selection, reproduction, variation, etc.). Because of dependency

  6. On-chip integration of a superconducting microwave circulator and a Josephson parametric amplifier

    Science.gov (United States)

    Rosenthal, Eric I.; Chapman, Benjamin J.; Moores, Bradley A.; Kerckhoff, Joseph; Malnou, Maxime; Palken, D. A.; Mates, J. A. B.; Hilton, G. C.; Vale, L. R.; Ullom, J. N.; Lehnert, K. W.

    Recent progress in microwave amplification based on parametric processes in superconducting circuits has revolutionized the measurement of feeble microwave signals. These devices, which operate near the quantum limit, are routinely used in ultralow temperature cryostats to: readout superconducting qubits, search for axionic dark matter, and characterize astrophysical sensors. However, these amplifiers often require ferrite circulators to separate incoming and outgoing traveling waves. For this reason, measurement efficiency and scalability are limited. In order to facilitate the routing of quantum signals we have created a superconducting, on-chip microwave circulator without permanent magnets. We integrate our circulator on-chip with a Josephson parametric amplifier for the purpose of near quantum-limited directional amplification. In this talk I will present a design overview and preliminary measurements.

  7. Two-phase natural circulation experiments in a pressurized water loop with CANDU geometry

    International Nuclear Information System (INIS)

    Ardron, K.H.; Krishnan, V.S.; McGee, G.R.; Anderson, J.W.D.; Hawley, E.H.

    1984-07-01

    To provide information on two-phase natural circulation in a CANDU-type coolant circuit a series of tests has been performed in the RD-12 loop at the Whiteshell Nuclear Research Establishment. RD-12 is a 10-MPa pressurized-water loop containing two active boilers, two pumps, and two, or four, heated horizontal channels arranged in a symmetrical figure-of-eight configuration characteristic of the CANDU reactor primary heat-transport system. In the tests, single-phase natural circulation was established in the loop and void was introduced by controlled draining, with the surge tank (pressurizer) valved out of the system. The paper reviews the experimental results obtained and describes the evolution of natural circulation flow in particular cases as voidage is progressively increased. The stability behaviour is discussed briefly with reference to a simple stability model

  8. Fritz Schott's Contributions to the Understanding of the Ocean Circulation

    Science.gov (United States)

    Visbeck, M.

    2009-04-01

    driving force behind the Collaborative Research Project "Dynamics of the Thermohaline Circulation" which was funded from 1996-2006 by the German Research Foundation (DFG). Within this project, he and his colleagues made major contributions to our understanding of the sinking of cold, dense waters in the northern North Atlantic, a process critical for the deep ocean circulation as well as the role played by the Gulf Stream and Deep Western Boundary current system for climate. The starting point of this project was again the observation of the ocean. Vertical velocity and hydrographic measurements during active convection carried out in the Greenland Sea, the Labrador Sea and the Gulf of Lions represents the observational basis of the fundamental work regarding the open-ocean convection.

  9. INVESTIGATION OF MECHANICAL STRESSES IN THE DRIVE SHAFT OF MV VACUUM CIRCUIT BREAKER

    Directory of Open Access Journals (Sweden)

    E. I. Baida

    2017-03-01

    Full Text Available Introduction. In the last 10-15 years a dominant position in the market of medium voltage circuit breakers, vacuum circuit breakers have taken in which as an actuator mono- or bistable actuators with permanent magnets are used. Such circuit breakers are characterized by simplicity of design, high reliability, require preventive maintenance for many years. Development, research and improvement of vacuum circuit breakers are carried out at the Department for Electrical Apparatus, National Technical University «Kharkiv Polytechnic Institute». While working on the circuit breakers, developers have to deal with two related objectives – electrical and mechanical. This paper considers the solution of one of these problems – calculation of mechanical forces in the drive shaft of the vacuum circuit breaker in static and dynamic modes. This work was preceded by the failure of the results of measurements of the prototype circuit breakers’ contacts. Measurements have shown that these values do not match the expected values (there were less than the value of 0.8 to 1 mm. The assumption about the reasons for this discrepancy needed to be detailed checked. The results of the work done are presented in this paper. Purpose. Investigation of static and dynamic mechanical stresses and strains in the drive shaft of the vacuum circuit breaker mechanism to determine its characteristics and material selection. Methods. The investigation of mechanical processes is performed by the finite element method in the COMSOL software package. Results. We obtain the static and dynamic characteristics of the circuit breaker drive shaft: deformations, reaction forces, stresses. These characteristics made it possible to determine the actual course of the contacts, select shaft material and calculate the forces acting on the bearings. Conclusions. It is shown that the contact velocity and contact pressure are different from the theoretical value due to the deformation of the

  10. Study of core flow distribution for small modular natural circulation lead or lead-alloy cooled fast reactors

    International Nuclear Information System (INIS)

    Chen, Zhao; Zhao, Pengcheng; Zhou, Guangming; Chen, Hongli

    2014-01-01

    Highlights: • A core flow distribution calculation code for natural circulation LFRs was developed. • The comparison study between the channel method and the CFD method was conducted. • The core flow distribution analysis and optimization design for a 10MW natural circulation LFR was conducted. - Abstract: Small modular natural circulation lead or lead-alloy cooled fast reactor (LFR) is a potential candidate for LFR development. It has many attractive advantages such as reduced capital costs and inherent safety. The core flow distribution calculation is an important issue for nuclear reactor design, which will provide important input parameters to thermal-hydraulic analysis and safety analysis. The core flow distribution calculation of a natural circulation LFR is different from that of a forced circulation reactor. In a forced circulation reactor, the core flow distribution can be controlled and adjusted by the pump power and the flow distributor, while in a natural circulation reactor, the core flow distribution is automatically adjusted according to the relationship between the local power and the local resistance feature. In this paper, a non-uniform heated parallel channel flow distribution calculation code was developed and the comparison study between the channel method and the CFD method was carried out to assess the exactness of the developed code. The core flow distribution analysis and optimization design for a 10MW natural circulation LFR was conducted using the developed code. A core flow distribution optimization design scheme for a 10MW natural circulation LFR was proposed according to the optimization analysis results

  11. Optimal planning of series resistor to control time constant of test circuit for high-voltage AC circuit-breakers

    OpenAIRE

    Yoon-Ho Kim; Jung-Hyeon Ryu; Jin-Hwan Kim; Kern-Joong Kim

    2016-01-01

    The equivalent test circuit that can deliver both short-circuit current and recovery voltage is used to verify the performance of high-voltage circuit breakers. Most of the parameters in this circuit can be obtained by using a simple calculation or a simulation program. The ratings of the circuit breaker include rated short-circuit breaking current, rated short-circuit making current, rated operating sequence of the circuit breaker and rated short-time current. Among these ratings, the short-...

  12. Chaotic dynamics with high complexity in a simplified new nonautonomous nonlinear electronic circuit

    International Nuclear Information System (INIS)

    Arulgnanam, A.; Thamilmaran, K.; Daniel, M.

    2009-01-01

    A two dimensional nonautonomous dissipative forced series LCR circuit with a simple nonlinear element exhibiting an immense variety of dynamical features is proposed for the first time. Unlike the usual cases of nonlinear element, the nonlinear element used here possesses three segment piecewise linear character with one positive and one negative slope. This nonlinearity is verified to be sufficient to produce chaos with high complexity in many established nonautonomous nonlinear circuits, such as MLC, MLCV, driven Chua, etc., thus indicating an universal behavior similar to the familiar Chua's diode. The dynamics of the proposed circuit is studied experimentally, confirmed numerically, simulated through PSPICE and proved mathematically. An important feature of the circuit is its ability to show dual chaotic behavior.

  13. Performance of the Main Dipole Magnet Circuits of the LHC during Commissioning

    CERN Document Server

    Verweij, A; Ballarino, A; Bellesia, B; Bordry, Frederick; Cantone, A; Casas Lino, M; Castaneda Serra, A; Castillo Trello, C; Catalan-Lasheras, N; Charifoulline, Z; Coelingh, G; Dahlerup-Petersen, K; D'Angelo, G; Denz, R; Fehér, S; Flora, R; Gruwé, M; Kain, V; Khomenko, B; Kirby, G; MacPherson, A; Marqueta Barbero, A; Mess, K H; Modena, M; Mompo, R; Montabonnet, V; le Naour, S; Nisbet, D; Parma, V; Pojer, M; Ponce, L; Raimondo, A; Redaelli, S; Reymond, H; Richter, D; de Rijk, G; Rijllart, A; Romera Ramirez, I; Saban, R; Sanfilippo, S; Schmidt, R; Siemko, A; Solfaroli Camillocci, M; Thurel, Y; Thiessen, H; Venturini-Delsolaro, W; Vergara Fernandez, A; Wolf, R; Zerlauth, M

    2008-01-01

    During hardware commissioning of the Large Hadron Collider (LHC), 8 main dipole circuits are tested at 1.9 K and up to their nominal current. Each dipole circuit contains 154 magnets of 15 m length, and has a total stored energy of up to 1.3 GJ. All magnets are wound from Nb-Ti superconducting Rutherford cables, and contain heaters to quickly force the transition to the normal conducting state in case of a quench, and hence reduce the hot spot temperature. In this paper the performance of the first three of these circuits is presented, focussing on quench detection, heater performance, operation of the cold bypass diodes, and magnet-to-magnet quench propagation. The results as measured on the entire circuits will be compared to the test results obtained during the reception tests of the individual magnets.

  14. Circuit for Driving Piezoelectric Transducers

    Science.gov (United States)

    Randall, David P.; Chapsky, Jacob

    2009-01-01

    The figure schematically depicts an oscillator circuit for driving a piezoelectric transducer to excite vibrations in a mechanical structure. The circuit was designed and built to satisfy application-specific requirements to drive a selected one of 16 such transducers at a regulated amplitude and frequency chosen to optimize the amount of work performed by the transducer and to compensate for both (1) temporal variations of the resonance frequency and damping time of each transducer and (2) initially unknown differences among the resonance frequencies and damping times of different transducers. In other words, the circuit is designed to adjust itself to optimize the performance of whichever transducer is selected at any given time. The basic design concept may be adaptable to other applications that involve the use of piezoelectric transducers in ultrasonic cleaners and other apparatuses in which high-frequency mechanical drives are utilized. This circuit includes three resistor-capacitor networks that, together with the selected piezoelectric transducer, constitute a band-pass filter having a peak response at a frequency of about 2 kHz, which is approximately the resonance frequency of the piezoelectric transducers. Gain for generating oscillations is provided by a power hybrid operational amplifier (U1). A junction field-effect transistor (Q1) in combination with a resistor (R4) is used as a voltage-variable resistor to control the magnitude of the oscillation. The voltage-variable resistor is part of a feedback control loop: Part of the output of the oscillator is rectified and filtered for use as a slow negative feedback to the gate of Q1 to keep the output amplitude constant. The response of this control loop is much slower than 2 kHz and, therefore, does not introduce significant distortion of the oscillator output, which is a fairly clean sine wave. The positive AC feedback needed to sustain oscillations is derived from sampling the current through the

  15. Coherent defects in superconducting circuits

    International Nuclear Information System (INIS)

    Mueller, Clemens

    2011-01-01

    The interaction of superconducting circuits with additional quantum systems is a topic that has found extensive study in the recent past. In the limit where the added system are incoherent, this is the standard field of decoherence and the system dynamics can be described by a simple master equation. In the other limit however, when the additional parts are coherent, the resulting time-evolution can become more complicated. In this thesis we have investigated the interaction of superconducting circuits with coherent and incoherent two-level defects. We have shown theoretical calculations characterizing this interaction for all relevant parameter regimes. In the weak coupling limit, the interaction can be described in an effective bath picture, where the TLS act as parts of a large, decohering environment. For strong coupling, however, the coherent dynamics of the full coupled system has to be considered. We show the calculations of the coupled time-evolution and again characterize the interaction by an effective decoherence rate. We also used experimental data to characterize the microscopic origin of the defects and the details of their interaction with the circuits. The results obtained by analyzing spectroscopic data allow us to place strong constraint on several microscopic models for the observed TLS. However, these calculations are not yet fully conclusive as to the physical nature of the TLS. We propose additional experiments to fully characterize the interaction part of the Hamiltonian, thus providing the answer to the question of the physical origin of the coupling. Additionally we have developed a method to directly drive individual defect states via virtual excitation of the qubit. This method allows one to directly probe the properties of single TLS and possibly make use of their superior coherence times for quantum information purposes. The last part of this thesis provided a way for a possible implementation of geometric quantum computation in

  16. Miniaturization of Josephson logic circuits

    International Nuclear Information System (INIS)

    Ko, H.; Van Duzer, T.

    1985-01-01

    The performances of Current Injection Logic (CIL) and Resistor Coupled Josephson Logic (RCJL) have been evaluated for minimum features sizes ranging from 5 μm to 0.2 μm. The logic delay is limited to about 10 ps for both the CIL AND gate and the RCJL OR gate biased at 70% of maximum bias current. The maximum circuit count on an 6.35 x 6.35 chip is 13,000 for CIL gates and 20,000 for RCJL gates. Some suggestions are given for further improvements

  17. Integrated circuits for multimedia applications

    DEFF Research Database (Denmark)

    Vandi, Luca

    2007-01-01

    , and it is applied to a broad-band dual-loop receiver architecture in order to boost the linearity performances of the stage. A simplified noise- and linearity analysis of the circuit is derived, and a comparison is provided with a more traditional dual-loop topology (a broad-band stage based on shunt...... the impact of substrate-induced currents. Basic models are derived in the design phase, and the technological limits of the device are considered. Measurement results show that a very compact coil can provide ~1nH inductance up to 20GHz (physical limit for the measurement equipment), with a peak quality...

  18. Model reduction for circuit simulation

    CERN Document Server

    Hinze, Michael; Maten, E Jan W Ter

    2011-01-01

    Simulation based on mathematical models plays a major role in computer aided design of integrated circuits (ICs). Decreasing structure sizes, increasing packing densities and driving frequencies require the use of refined mathematical models, and to take into account secondary, parasitic effects. This leads to very high dimensional problems which nowadays require simulation times too large for the short time-to-market demands in industry. Modern Model Order Reduction (MOR) techniques present a way out of this dilemma in providing surrogate models which keep the main characteristics of the devi

  19. HF radio systems and circuits

    CERN Document Server

    Sabin, William

    1998-01-01

    A comprehensive reference for the design of high frequency communications systems and equipment. This revised edition is loaded with practical data, much of which cannot be found in other reference books. Its approach to the subject follows the needs of an engineer from system definition and performance requirements down to the individual circuit elements that make up radio transmitters and receivers. The accompanying disk contains updated software on filters, matching networks and receiver analysis. SciTech Publishing also provides many other products related to Communication Systems Design.

  20. Polysilicon photoconductor for integrated circuits

    Science.gov (United States)

    Hammond, R.B.; Bowman, D.R.

    1989-04-11

    A photoconductive element of polycrystalline silicon is provided with intrinsic response time which does not limit overall circuit response. An undoped polycrystalline silicon layer is deposited by LPCVD to a selected thickness on silicon dioxide. The deposited polycrystalline silicon is then annealed at a selected temperature and for a time effective to obtain crystal sizes effective to produce an enhanced current output. The annealed polycrystalline layer is subsequently exposed and damaged by ion implantation to a damage factor effective to obtain a fast photoconductive response. 6 figs.

  1. Wideband 4-diode sampling circuit

    Science.gov (United States)

    Wojtulewicz, Andrzej; Radtke, Maciej

    2016-09-01

    The objective of this work was to develop a wide-band sampling circuit. The device should have the ability to collect samples of a very fast signal applied to its input, strengthen it and prepare for further processing. The study emphasizes the method of sampling pulse shaping. The use of ultrafast pulse generator allows sampling signals with a wide frequency spectrum, reaching several gigahertzes. The device uses a pulse transformer to prepare symmetrical pulses. Their final shape is formed with the help of the step recovery diode, two coplanar strips and Schottky diode. Made device can be used in the sampling oscilloscope, as well as other measurement system.

  2. Circuit QED with transmon qubits

    Energy Technology Data Exchange (ETDEWEB)

    Wulschner, Karl Friedrich; Puertas, Javier; Baust, Alexander; Eder, Peter; Fischer, Michael; Goetz, Jan; Haeberlein, Max; Schwarz, Manuel; Xie, Edwar; Zhong, Ling; Deppe, Frank; Fedorov, Kirill; Marx, Achim; Menzel, Edwin; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Huebl, Hans [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Weides, Martin [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany)

    2015-07-01

    Superconducting quantum bits are basic building blocks for circuit QED systems. Applications in the fields of quantum computation and quantum simulation require long coherence times. We have fabricated and characterized superconducting transmon qubits which are designed to operate at a high ratio of Josephson energy and charging energy. Due to their low sensitivity to charge noise transmon qubits show good coherence properties. We couple transmon qubits to coplanar waveguide resonators and coplanar slotline resonators and characterize the devices at mK-temperatures. From the experimental data we derive the qubit-resonator coupling strength, the qubit relaxation time and calibrate the photon number in the resonator via Stark shifts.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-01-01

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

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

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  5. Eddy current analysis by the finite element circuit method

    International Nuclear Information System (INIS)

    Kameari, A.; Suzuki, Y.

    1977-01-01

    The analysis of the transient eddy current in the conductors by ''Finite Element Circuit Method'' is developed. This method can be easily applied to various geometrical shapes of thin conductors. The eddy currents on the vacuum vessel and the upper and lower support plates of JT-60 machine (which is now being constructed by Japan Atomic Energy Research Institute) are calculated by this method. The magnetic field induced by the eddy current is estimated in the domain occupied by the plasma. And the force exerted to the vacuum vessel is also estimated

  6. Recrystallization Experiments of Pyrite From Circulating Hydrothermal Solution by Thermal Convection

    Science.gov (United States)

    Tanaka, K.; Isobe, H.

    2005-12-01

    Pyrite is one of the most common accessory minerals in many rocks and generally occurs in hydrothermal deposit. However, pyrite morphology and association with other sulfide minerals is not well known with respect to the solution condition, especially with the hydrothermal solution under circulation. In this study, recrystallization experiments of pyrite from circulating hydrothermal solution by thermal convection were carried out. A rectangular circuit (42.6 cm by 17.3 cm) of SUS316 pressure tubing with 5 mm in inner diameter was used as a reaction vessel. The volume of the circuit is approximately 24 ml. Long sides of the rectangular circuit were held to be 20 degrees inclination. One of the long sides was heated by an electric furnace. Solution in the circuit evaporates in the high temperature tubing and the vapor condenses in room temperature tubing. The solution backs to the bottom of the high temperature tubing. Thus, thermal convection of the solution produces circulation in the circuit. Starting material was filled in the high temperature tubing. The lower half was filled with mixture of 2 g of powdered natural pyrite and 4 g of quartz grains. The upper half was filled with quartz grains only. 9 ml of 5 mol/l NH4Cl solution was sealed in the circuit with the starting material. Temperature gradient of the sample was monitored by 6 thermocouples. Maximum temperature was controlled at 350°C. Experimental durations are 3, 5, 10 and 30 days. After the experiments, the run products are fixed with resin and cut every 2 cm. Thin sections of vertical cross-sections are made and observed by microscope and SEM. Tiny pyrite crystals occurred at the upper outside of the furnace, where temperature should be much lower than 200°C. In the lower half of the starting material, pyrite decomposed and pyrrhotite formed around pyrite grains. At higher temperature area, pyrite decomposition and pyrrhotite formation is remarkable. Circulating sulfur-bearing solution provided by

  7. Climate hypersensitivity to solar forcing?

    Directory of Open Access Journals (Sweden)

    W. Soon

    2000-05-01

    Full Text Available We compare the equilibrium climate responses of a quasi-dynamical energy balance model to radiative forcing by equivalent changes in CO2, solar total irradiance (Stot and solar UV (SUV. The response is largest in the SUV case, in which the imposed UV radiative forcing is preferentially absorbed in the layer above 250 mb, in contrast to the weak response from global-columnar radiative loading by increases in CO2 or Stot. The hypersensitive response of the climate system to solar UV forcing is caused by strongly coupled feedback involving vertical static stability, tropical thick cirrus ice clouds and stratospheric ozone. This mechanism offers a plausible explanation of the apparent hypersensitivity of climate to solar forcing, as suggested by analyses of recent climatic records. The model hypersensitivity strongly depends on climate parameters, especially cloud radiative properties, but is effective for arguably realistic values of these parameters. The proposed solar forcing mechanism should be further confirmed using other models (e.g., general circulation models that may better capture radiative and dynamical couplings of the troposphere and stratosphere.Key words: Meteorology and atmospheric dynamics (climatology · general or miscellaneous · Solar physics · astrophysics · and astronomy (ultraviolet emissions

  8. Mechanisms governing the physico-chemical processes of transfer in NPP circuits

    International Nuclear Information System (INIS)

    Brusakov, V.P.; Sedov, V.M.; Khitrov, Yu.A.; Rybalchenko, I.L.

    1983-01-01

    The paper deals with the theoretical physico-chemical processes of corrosion products and their radionuclide transport in NPS circuits by thermoelectromotive and electromotive forces of microgalvanic couples. The laboratory and rig test results as well as the NPP operating experience data confirm the developed theoretical concept validity

  9. Isolation of Circulating Tumor Cells by Dielectrophoresis

    Directory of Open Access Journals (Sweden)

    Peter R. C. Gascoyne

    2014-03-01

    Full Text Available Dielectrophoresis (DEP is an electrokinetic method that allows intrinsic dielectric properties of suspended cells to be exploited for discrimination and separation. It has emerged as a promising method for isolating circulation tumor cells (CTCs from blood. DEP-isolation of CTCs is independent of cell surface markers. Furthermore, isolated CTCs are viable and can be maintained in culture, suggesting that DEP methods should be more generally applicable than antibody-based approaches. The aim of this article is to review and synthesize for both oncologists and biomedical engineers interested in CTC isolation the pertinent characteristics of DEP and CTCs. The aim is to promote an understanding of the factors involved in realizing DEP-based instruments having both sufficient discrimination and throughput to allow routine analysis of CTCs in clinical practice. The article brings together: (a the principles of DEP; (b the biological basis for the dielectric differences between CTCs and blood cells; (c why such differences are expected to be present for all types of tumors; and (d instrumentation requirements to process 10 mL blood specimens in less than 1 h to enable routine clinical analysis. The force equilibrium method of dielectrophoretic field-flow fractionation (DEP-FFF is shown to offer higher discrimination and throughput than earlier DEP trapping methods and to be applicable to clinical studies.

  10. Isolation of Circulating Tumor Cells by Dielectrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Gascoyne, Peter R. C., E-mail: pgascoyn@mdanderson.org [Department of Imaging Physics Research, The University of Texas M.D. Anderson Cancer Center Unit 951, 1515 Holcombe Boulevard, Houston, TX 77030 (United States); Shim, Sangjo [Department of Imaging Physics Research, The University of Texas M.D. Anderson Cancer Center Unit 951, 1515 Holcombe Boulevard, Houston, TX 77030 (United States); Department of Biomedical Engineering, The University of Texas at Austin, 1 University Station, C0800, Austin, TX 78712 (United States); Present address: Micro & Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, 208 North Wright Street, Urbana, IL 61801 (United States)

    2014-03-12

    Dielectrophoresis (DEP) is an electrokinetic method that allows intrinsic dielectric properties of suspended cells to be exploited for discrimination and separation. It has emerged as a promising method for isolating circulation tumor cells (CTCs) from blood. DEP-isolation of CTCs is independent of cell surface markers. Furthermore, isolated CTCs are viable and can be maintained in culture, suggesting that DEP methods should be more generally applicable than antibody-based approaches. The aim of this article is to review and synthesize for both oncologists and biomedical engineers interested in CTC isolation the pertinent characteristics of DEP and CTCs. The aim is to promote an understanding of the factors involved in realizing DEP-based instruments having both sufficient discrimination and throughput to allow routine analysis of CTCs in clinical practice. The article brings together: (a) the principles of DEP; (b) the biological basis for the dielectric differences between CTCs and blood cells; (c) why such differences are expected to be present for all types of tumors; and (d) instrumentation requirements to process 10 mL blood specimens in less than 1 h to enable routine clinical analysis. The force equilibrium method of dielectrophoretic field-flow fractionation (DEP-FFF) is shown to offer higher discrimination and throughput than earlier DEP trapping methods and to be applicable to clinical studies.

  11. Isolation of Circulating Tumor Cells by Dielectrophoresis

    International Nuclear Information System (INIS)

    Gascoyne, Peter R. C.; Shim, Sangjo

    2014-01-01

    Dielectrophoresis (DEP) is an electrokinetic method that allows intrinsic dielectric properties of suspended cells to be exploited for discrimination and separation. It has emerged as a promising method for isolating circulation tumor cells (CTCs) from blood. DEP-isolation of CTCs is independent of cell surface markers. Furthermore, isolated CTCs are viable and can be maintained in culture, suggesting that DEP methods should be more generally applicable than antibody-based approaches. The aim of this article is to review and synthesize for both oncologists and biomedical engineers interested in CTC isolation the pertinent characteristics of DEP and CTCs. The aim is to promote an understanding of the factors involved in realizing DEP-based instruments having both sufficient discrimination and throughput to allow routine analysis of CTCs in clinical practice. The article brings together: (a) the principles of DEP; (b) the biological basis for the dielectric differences between CTCs and blood cells; (c) why such differences are expected to be present for all types of tumors; and (d) instrumentation requirements to process 10 mL blood specimens in less than 1 h to enable routine clinical analysis. The force equilibrium method of dielectrophoretic field-flow fractionation (DEP-FFF) is shown to offer higher discrimination and throughput than earlier DEP trapping methods and to be applicable to clinical studies

  12. Dynamics and developing of natural circulation cooling from vertical upflow and downflow conditions

    International Nuclear Information System (INIS)

    Yang, B.W.; Ouyang, W.

    2004-01-01

    Several research programs have been conducted to evaluate the capability of natural circulation cooling of reactors following a loss of cooling accident. Both experimental and RELAP5 simulation results were obtained for these studies in a facility with vertical heated tube(s) and a unheated bypass channel. The analytical results showed that, under a certain power level, a natural circulation pattern can be developed from both initial upflow and downflow conditions, and maintained for a significant cooling period. This power level, for the discussion of this paper, is defined as the natural circulation cooling (NCC) power limit. Two import factors, namely the pump coastdown rate and the initial flow direction, are examined in this paper. In the benchmark case, as compared to the experimental results, the RELAP5 simulation program accurately predicted the transient phenomena from forced convection through flow reversal, then, into natural circulation cooling. Generally, the two-phase NCC power limit is higher and also more stable for the cases with initial upflow forced convection than for the cases with initial downflow. The transient phenomena (dynamics) of the natural circulation cooling was examined by varying the pump coast down rate in approaching the flow reversal natural circulation. A significant pump coastdown effect on the NCC power limit was observed for the analytical tests with initial downflow forced convection. For the tests with initial downflow condition, the higher the coastdown rate (or the shorter the coastdown period), the higher the NCC power limit. For the case with initial upflow forced convection, there may be an optimal coastdown rate for a given subcooled condition. However, for the subcooled condition used in this study, the effect of pump coast down rate is not as significant as in the downward forced convection. (author)

  13. The Southern Ocean's role in ocean circulation and climate transients

    Science.gov (United States)

    Thompson, A. F.; Stewart, A.; Hines, S.; Adkins, J. F.

    2017-12-01

    The ventilation of deep and intermediate density classes at the surface of the Southern Ocean impacts water mass modification and the air-sea exchange of heat and trace gases, which in turn influences the global overturning circulation and Earth's climate. Zonal variability occurs along the Antarctic Circumpolar Current and the Antarctic margins related to flow-topography interactions, variations in surface boundary conditions, and exchange with northern basins. Information about these zonal variations, and their impact on mass and tracer transport, are suppressed when the overturning is depicted as a two-dimensional (depth-latitude) streamfunction. Here we present an idealized, multi-basin, time-dependent circulation model that applies residual circulation theory in the Southern Ocean and allows for zonal water mass transfer between different ocean basins. This model efficiently determines the temporal evolution of the ocean's stratification, ventilation and overturning strength in response to perturbations in the external forcing. With this model we explore the dynamics that lead to transitions in the circulation structure between multiple, isolated cells and a three-dimensional, "figure-of-eight," circulation in which traditional upper and lower cells are interleaved. The transient model is also used to support a mechanistic explanation of the hemispheric asymmetry and phase lag associated with Dansgaard-Oeschger (DO) events during the last glacial period. In particular, the 200 year lag in southern hemisphere temperatures, following a perturbation in North Atlantic deep water formation, depends critically on the migration of Southern Ocean isopycnal outcropping in response to low-latitude stratification changes. Our results provide a self-consistent dynamical framework to explain various ocean overturning transitions that have occurred over the Earth's last 100,000 years, and motivate an exploration of these mechanisms in more sophisticated climate models.

  14. Realizing a supercapacitor in an electrical circuit

    International Nuclear Information System (INIS)

    Fukuhara, Mikio; Kuroda, Tomoyuki; Hasegawa, Fumihiko

    2014-01-01

    Capacitors are commonly used in electronic resonance circuits; however, capacitors have not been used for storing large amounts of electrical energy in electrical circuits. Here, we report a superior RC circuit which serves as an electrical storage system characterized by quick charging and long-term discharging of electricity. The improved energy storage characteristics in this mixed electric circuit (R 1  + R 2 C 1 ) with small resistor R 1 , large resistor R 2 , and large capacitor C 1 are derived from the damming effect by large R 2 in simple parallel R 2 C 1 circuit. However, no research work has been carried out previously on the use of capacitors as electrical energy storage devices in circuits. Combined with nanotechnology, we hope that our finding will play a remarkable role in a variety of applications such as hybrid electric vehicles and backup power supplies

  15. Diarrhea caused by circulating agents.

    Science.gov (United States)

    Fabian, Elisabeth; Kump, Patrizia; Krejs, Guenter J

    2012-09-01

    Circulating agents cause intestinal secretion or changes in motility with decreased intestinal transit time, resulting in secretory-type diarrhea. Secretory diarrhea as opposed to osmotic diarrhea is characterized by large-volume, watery stools, often more than 1 L per day; by persistence of diarrhea when patients fast; and by the fact that on analysis of stool-water, measured osmolarity is identical to that calculated from the electrolytes present. Although sodium plays the main role in water and electrolyte absorption, chloride is the major ion involved in secretion. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Vasculitis of the mesenteric circulation.

    Science.gov (United States)

    Koster, Matthew J; Warrington, Kenneth J

    2017-02-01

    Vasculitis of the mesenteric circulation is an uncommon but life-threatening manifestation of systemic vasculitis. Initial symptoms are frequently non-specific and therefore patients often present to primary care physicians and gastroenterologists with abdominal pain or gastrointestinal bleeding. Given the severity of the conditions associated with mesenteric vasculitis, it is imperative to appropriately diagnose and initiate treatment of suspected cases. This review will focus on diseases commonly associated with vasculitis of the mesenteric vessels. Imaging characteristics and clinical features assisting in diagnosis as well as initial approaches to treatment are emphasized. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Autonomic Regulation of Splanchnic Circulation

    Directory of Open Access Journals (Sweden)

    Kathleen A Fraser

    1991-01-01

    Full Text Available The role of the autonomic nervous system in circulatory regulation of the splanchnic organs (stomach, small intestine, colon, liver, pancreas and spleen is reviewed. In general, the sympathetic nervous system is primarily involved in vasoconstriction, while the parasympathetic contributes to vasodilation. Vasoconstriction in the splanchnic circulation appears to be mediated by alpha-2 receptors and vasodilation by activation of primary afferent nerves with subsequent release of vasodilatory peptides, or by stimulation of beta-adrenergic receptors. As well, an important function of the autonomic nervous system is to provide a mechanism by which splanchnic vascular reserve can be mobilized during stress to maintain overall cardiovascular homeostasis.

  18. 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)

  19. Simulation of barotropic wind-driven circulation in tbe Bay of Bengal and Andaman Sea during premonsoon and postmonsoon seasons

    Digital Repository Service at National Institute of Oceanography (India)

    Unnikrishnan, A.S.; Bahulayan, N.

    Two-dimensional vertically integrated model has been used to simulate depth-mean wind-driven circulation during premonsoon and postmonsoon seasons in the upper layers of the Bay of Bengal and Andaman Sea. The model is integrated for 365 d, forcEd...

  20. The analysis and design of linear circuits

    CERN Document Server

    Thomas, Roland E; Toussaint, Gregory J

    2009-01-01

    The Analysis and Design of Linear Circuits, 6e gives the reader the opportunity to not only analyze, but also design and evaluate linear circuits as early as possible. The text's abundance of problems, applications, pedagogical tools, and realistic examples helps engineers develop the skills needed to solve problems, design practical alternatives, and choose the best design from several competing solutions. Engineers searching for an accessible introduction to resistance circuits will benefit from this book that emphasizes the early development of engineering judgment.