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Sample records for current limiter sfcl

  1. Current limiting characteristics of transformer type SFCL with coupled secondary windings according to its winding direction

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sung Hun [Dept. of Electrical Engineering, Soongsil University, Seoul (Korea, Republic of); Han, Tae Hee [Dept. of Aero Materials Engineering, Jungwon University, Goesan (Korea, Republic of)

    2017-06-15

    In this paper, the current limiting characteristics of the transformer type superconducting fault current limiter (SFCL) with the two coupled secondary windings due to its winding direction were analyzed. To analyze the dependence of transient fault current limiting characteristics on the winding direction of the additional secondary winding, the fault current limiting tests of the SFCL with an additional secondary winding, wound as subtractive polarity winding and additive polarity winding, were carried out. The time interval of quench occurrence between two superconducting elements comprising the transformer type SFCL with the additional secondary winding was confirmed to be affected by the winding direction of the additional secondary winding. In case of the subtractive polarity winding of the additional secondary winding, the time interval of the quench occurrence in two superconducting elements was shorter than the case of the additive polarity winding.

  2. Proposal of rectifier type superconducting fault current limiter with non-inductive reactor (SFCL)

    Science.gov (United States)

    Mohammad Salim, Khosru; Muta, Itsuya; Hoshino, Tsutomu; Nakamura, Taketsune; Yamada, Masato

    2004-03-01

    A rectifier type superconducting fault current limiter (SFCL) with non-inductive reactor has been proposed. The concept behind this SFCL is the appearance of high impedance during non-superconducting state of the coil. In a hybrid bridge circuit, two superconducting coils connected in anti-parallel: a trigger coil and a limiting coil. Both the coils are magnetically coupled with each other and have same number of turns. There is almost zero flux inside the core and therefore the total inductance is small during normal operation. At fault time when the trigger coil current reaches to a certain level, the trigger coil changes from superconducting state to normal state. This super-to-normal transition of the trigger coil changes the current ratio of the coils and therefore the flux inside the reactor is no longer zero. So, the equivalent impedance of both the coils increased thus limits the fault current. We have carried out computer simulation using EMTDC and observed the results. A preliminary experiment has already been performed using copper wired reactor with simulated super-to-normal transition resistance and magnetic switches. Both the simulation and preliminary experiment shows good results. The advantage of using hybrid bridge circuit is that the SFCL can also be used as circuit breaker. Two separate bridge circuit can be used for both trigger coil and the limiter coil. In such a case, the trigger coil can be shutdown immediately after the fault to reduce heat and thus reduce the recovery time. Again, at the end of fault when the SFCL needs to re-enter to the grid, turning off the trigger circuit in the two-bridge configuration the inrush current can be reduced. This is because the current only flows through the limiting coil. Another advantage of this type of SFCL is that no voltage sag will appear during load increasing time as long as the load current stays below the trigger current level.

  3. Design, Fabrication and Testing of a Superconducting Fault Current Limiter (SFCL)

    Energy Technology Data Exchange (ETDEWEB)

    Gouge, M..; Schwenterly, S.W.; Hazelton, D. (SuperPower, Inc.)

    2011-06-15

    The purpose of this project was to conduct R&D on specified components and provide technical design support to a SuperPower team developing a high temperature superconducting Fault Current Limiter (SFCL). ORNL teamed with SuperPower, Inc. on a Superconductivity Partnerships with Industry (SPI) proposal for the SFCL that was submitted to DOE and approved in FY 2003. A contract between DOE and SuperPower, Inc. was signed on July 14, 2003 to design, fabricate and test the SFCL. This device employs high temperature superconducting (HTS) elements and SuperPower's proprietary technology. The program goal was to demonstrate a device that will address a broad range of the utility applications and meet utility industry requirements. This DOE-sponsored Superconductivity Partnership with Industry project would positively impact electric power transmission reliability and security by introducing a new element in the grid that can significantly mitigate fault currents and provide lower cost solutions for grid protection. The project will conduct R&D on specified components and provide technical design support to a SuperPower-led team developing a SFCL as detailed in tasks 1-5 below. Note the SuperPower scope over the broad SPI project is much larger than that shown below which indicates only the SuperPower tasks that are complementary to the ORNL tasks. SuperPower is the Project Manager for the SFCL program, and is responsible for completion of the project on schedule and budget. The scope of work for ORNL is to provide R&D support for the SFCL in the following four broad areas: (1) Assist with high voltage subsystem R&D, design, fabrication and testing including characterization of the general dielectric performance of LN2 and component materials; (2) Consult on cryogenic subsystem R&D, design, fabrication and testing; (3) Participate in project conceptual and detailed design reviews; and (4) Guide commercialization by participation on the Technical Advisory Board (TAB

  4. Current Limiting Performance of Three-Phase Concentric Transformer Type SFCL at Unbalanced Fault Conditions

    OpenAIRE

    Shirai, Yasuyuki; Noda, Syo; Yamabe, Kenta; Hattori, Keisuke; Baba, Jumpei; Nishihara, Taichi; Nitta, Tanzo; Kobayashi, Shinichi; Sato, Kenichi

    2013-01-01

    We have proposed a transformer type SFCL whose primary and secondary superconducting coils have rewound structure. The primary coil is connected to a power line. The secondary one is short-circuited and has fewer turns than the primary coil. For small fault current, only the secondary coil turns to normal state. Inductive component of impedance at the primary terminal mainly appears. For larger fault current, the primary coil also turns to normal state, resistive component additively appears....

  5. Comparison of the quench and fault current limiting characteristics of the flux-coupling type SFCL with single and three-phase transformer

    Science.gov (United States)

    Jung, Byung Ik; Cho, Yong Sun; Park, Hyoung Min; Chung, Dong Chul; Choi, Hyo Sang

    2013-01-01

    The South Korean power grid has a network structure for the flexible operation of the system. The continuously increasing power demand necessitated the increase of power facilities, which decreased the impedance in the power system. As a result, the size of the fault current in the event of a system fault increased. As this increased fault current size is threatening the breaking capacity of the circuit breaker, the main protective device, a solution to this problem is needed. The superconducting fault current limiter (SFCL) has been designed to address this problem. SFCL supports the stable operation of the circuit breaker through its excellent fault-current-limiting operation [1-5]. In this paper, the quench and fault current limiting characteristics of the flux-coupling-type SFCL with one three-phase transformer were compared with those of the same SFCL type but with three single-phase transformers. In the case of the three-phase transformers, both the superconducting elements of the fault and sound phases were quenched, whereas in the case of the single-phase transformer, only that of the fault phase was quenched. For the fault current limiting rate, both cases showed similar rates for the single line-to-ground fault, but for the three-wire earth fault, the fault current limiting rate of the single-phase transformer was over 90% whereas that of the three-phase transformer was about 60%. It appears that when the three-phase transformer was used, the limiting rate decreased because the fluxes by the fault current of each phase were linked in one core. When the power loads of the superconducting elements were compared by fault type, the initial (half-cycle) load was great when the single-phase transformer was applied, whereas for the three-phase transformer, its power load was slightly lower at the initial stage but became greater after the half fault cycle.

  6. Simulating the effect of SFCL on limiting the internal fault of synchronous machine

    Energy Technology Data Exchange (ETDEWEB)

    Kheirizad, I [Islamic Republic of Iran Broadcasting, Tehran (Iran, Islamic Republic of); Varahram, M H [Ministry of Science, Research and Technology, Tehran (Iran, Islamic Republic of); Jahed-Motlagh, M R [Azad University of Science and Research, Tehran (Iran, Islamic Republic of); Rahnema, M; Mohammadi, A [Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)], E-mail: hadi_varahram@yahoo.com

    2008-02-01

    In this paper, we have modelled a synchronous generator with internal one phase to ground fault and then the performance of this machine with internal one phase to ground fault have been analyzed. The results show that if the faults occur in vicinity of machine's terminal, then we would have serious damages. To protect the machine from this kind of faults we have suggested integrating a SFCL (superconducting fault current limiter) into the machine's model. The results show that the fault currents in this case will reduce considerably without influencing the normal operation of the machine.

  7. Superconducting fault current limiter for railway transport

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, L. M., E-mail: LMFisher@niitfa.ru; Alferov, D. F.; Akhmetgareev, M. R.; Budovskii, A. I.; Evsin, D. V.; Voloshin, I. F.; Kalinov, A. V. [National Technical Physics and Automation Research Institute (Russian Federation)

    2015-12-15

    A resistive switching superconducting fault current limiter (SFCL) for DC networks with voltage of 3.5 kV and nominal current of 2 kA is developed. The SFCL consists of two series-connected units: block of superconducting modules and high-speed vacuum breaker with total disconnection time not more than 8 ms. The results of laboratory tests of superconducting SFCL modules in current limiting mode are presented. The recovery time of superconductivity is experimentally determined. The possibility of application of SFCL on traction substations of Russian Railways is considered.

  8. Utility survey of requirements for a HTS fault current limiter

    DEFF Research Database (Denmark)

    Nielsen, Jan Nygaard; Jørgensen, P.; Østergaard, Jacob;

    2000-01-01

    The application of superconducting fault current limiters (SFCL) in the electric utility sector will clearly dependent on to what extent the needs and requirements of electric utilities can be met by the ongoing development of SFCL technology. This paper considers a questionnaire survey of which ...... needs and expectations the Danish electric utilities have to this new technology. A bus-tie application of SFCL in a distribution substation with three parallel-coupled transformers is discussed......The application of superconducting fault current limiters (SFCL) in the electric utility sector will clearly dependent on to what extent the needs and requirements of electric utilities can be met by the ongoing development of SFCL technology. This paper considers a questionnaire survey of which...

  9. Cooling performance test of the superconducting fault current limiter

    Energy Technology Data Exchange (ETDEWEB)

    Yeom, H.; Hong, Y. J.; Ko, J.; In, S.; Kim, H. B.; Park, S. J. [Korea Institute ofMachinery and Materials, Daejeon (Korea, Republic of); Kim, H.; Kim, H. R. [Korea Electric Power Corporation Research Institute, Daejeon (Korea, Republic of)

    2014-12-15

    The superconducting fault current limiter (SFCL) is an electrical power system device that detects the fault current automatically and limits the magnitude of the current below a certain safety level. The SFCL module does not have any electrical resistance below the critical temperature, which facilitates lossless power transmission in the electric power system. Once given the fault current, however, the superconducting conductor exhibits extremely high electrical resistance, and the magnitude of the current is accordingly limited to a low value. Therefore, SFCL should be maintained at a temperature below the critical temperature, which justifies the cryogenic cooling system as a mandatory component. This report is a study which reported on the cooling system for the 154 kV-class hybrid SFCL owned by Korea Electric Power Corporation (KEPCO). Using the cryocooler, the temperature of liquid nitrogen (LN2) was lowered to 71 K. The cryostat was pressurized to 5 bars to improve the dielectric strength of nitrogen and suppress nitrogen bubble foaming during operation of SFCL. The SFCL module was immersed in the liquid nitrogen of the cryostat to maintain the superconducting state. The performance test results of the key components such as cryocooler, LN2 circulation pump, cold box, and pressure builder are shown in this paper.

  10. Current distribution mapping in insulated (Gd,Y)BCO based stabilizer-free coated conductor after AC over-current test for R-SFCL application

    Science.gov (United States)

    Kar, Soumen; Li, Xiao-Fen; Selvamanickam, Venkat; Rao, V. V.

    2017-02-01

    Uniformity of critical current (Ic ) over long lengths of (GdY)-Ba-Cu-O ((Gd,Y)BCO)-based high temperature superconducting (HTS) tapes after long periods of AC current excitation is an important criterion in their selection for resistive type superconducting fault current limiter (R-SFCL). The present work describes such critical current (Ic ) uniformity measurements performed over 1m long, stabilizer-free (SF), 12 mm wide, 2nd generation (2G) (Gd,Y)BCO based HTS tape. A non-destructive method using a static hall probe (Tapestar®) with moving HTS tape configuration was employed for estimation of Ic uniformity. Scanning Hall probe microscopy (SHPM) was then used to examine the weak superconducting regions (i.e. less Ic ) with a static HTS tape. Remanent field distribution on the HTS tape was measured to yield the critical current density distribution. Except for small degradation of Ic at some locations, these studies confirmed near-uniform critical current distribution over meter-long (Gd,Y)BCO tapes, both in virgin state and after exposure to AC over current.

  11. A study on optimal SFCL specification to enhance the transfer capability on Korean power system

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Minhan, E-mail: radiance0@korea.ac.kr [School of Electrical Engineering, Korea University, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-713 (Korea, Republic of); Lee, Hansang [School of Railway and Electrical Engineering, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Cho, Yoonsung [Department of Electric and Energy Engineering, Catholic university of Daegu, Gyeongbuk 712-702 (Korea, Republic of); Jung, Seungmin [School of Electrical Engineering, Korea University, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-713 (Korea, Republic of); Jang, Gilsoo, E-mail: gjang@korea.ac.kr [School of Electrical Engineering, Korea University, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-713 (Korea, Republic of)

    2014-09-15

    Highlights: • The fault current problem is a severe issue in the Korean power system in the future. • The fault current contribution method has been used with the real Korean power system planning data. • The effectiveness of the SFCL application is verified using the proposed algorithm. - Abstract: The Korea Electric Power Corporation (KEPCO) power system has the characteristics of the load being concentrated in the Seoul metropolitan region and direct power transfer from generations located at distant points in the system thereby resulting in high levels of fault current in the metropolitan region during fault conditions. This fault current problem in the metropolitan region has been a critical issue during the past few years where the increase in the load elevates the fault current levels thereby requiring the replacement of numerous circuit breakers. In order to reduce the fault current levels in the system, the installation of superconductivity fault current limiter (SFCL) has been considered as a solution to reduce the fault current levels in the system. In this paper, an optimal SFCL specification is proposed, by using the fault current contribution method, for siting the optimal location of the SFCL to minimize the current injection into the fault point. The effectiveness of the SFCL application is being verified by simulations based on the KEPCO power system planning data where several installation points are examined for effective reduction of the fault current issue in the system.

  12. Operational characteristics in the three-phase transformer-type SFCL with neutral line based on sequential reclosing process

    Science.gov (United States)

    Cho, Y. S.; Choi, H. S.; Jung, B. I.

    2011-11-01

    In a transformer-type superconducting fault current limiter (SFCL) with a neutral line, which is connected between the superconducting elements and secondary windings, we verified that the SFCL has excellent characteristics that induce the perfect simultaneous quench of the superconducting elements in the previous study. The application of the SFCL to the power networks requires its coordination with the reclosing operation duty, which protects a circuit. In this study, the fault current limiting and recovery characteristics of superconducting elements in the three-phase transformer-type SFCL with the neutral line were analyzed. The limiting rate of the fault current in the transformer-type SFCL could increased by an iron core, which allows quenching of the superconducting elements in a sound phase as well as in a faulted phase. In addition, the simultaneous quench led to uniform burdens on superconducting elements, all of which recovered their superconducting state within an opening cycle of a circuit breaker. Thus, the transformer-type SFCL with the neutral line could reliably conduct the fault current limiting and recovery operations of superconducting elements according to the reclosing operation duty and fault types.

  13. Transmission Level High Temperature Superconducting Fault Current Limiter

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Gary [SuperPower, Inc., Schenectady, NY (United States)

    2016-10-05

    The primary objective of this project was to demonstrate the feasibility and reliability of utilizing high temperature superconducting (HTS) materials in a Transmission Level Superconducting Fault Current Limiter (SFCL) application. During the project, the type of high temperature superconducting material used evolved from 1st generation (1G) BSCCO-2212 melt cast bulk high temperature superconductors to 2nd generation (2G) YBCO based high temperature superconducting tape. The SFCL employed SuperPower's “Matrix” technology that offers modular features to enable scale up to transmission voltage levels. The SFCL consists of individual modules that contain elements and parallel inductors that assist in carrying the current during the fault. A number of these modules are arranged in an m x n array to form the current limiting matrix.

  14. Transmission Level High Temperature Superconducting Fault Current Limiter

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Gary [SuperPower, Inc., Schenectady, NY (United States)

    2016-10-05

    The primary objective of this project was to demonstrate the feasibility and reliability of utilizing high-temperature superconducting (HTS) materials in a Transmission Level Superconducting Fault Current Limiter (SFCL) application. During the project, the type of high-temperature superconducting material used evolved from 1st generation (1G) BSCCO-2212 melt cast bulk high-temperature superconductors to 2nd generation (2G) YBCO-based high-temperature superconducting tape. The SFCL employed SuperPower's “Matrix” technology, that offers modular features to enable scale up to transmission voltage levels. The SFCL consists of individual modules that contain elements and parallel inductors that assist in carrying the current during the fault. A number of these modules are arranged in an m x n array to form the current-limiting matrix.

  15. The impact of SFCL and SMES integration on the distance relay

    Science.gov (United States)

    Yang, Jun; Zhang, Liling; Wang, Xinpu; Chen, Lei; Chen, Yanxia

    2016-11-01

    The superconducting fault current limiter (SFCL) is an ideal short-circuit fault current limiting device that can limit the fault current without any delay and control the voltage drop of the non-fault line. The superconducting magnetic energy storage (SMES) device can exchange the active and reactive power independently, so it is applied broadly to improve power system stability. With SFCL, the low voltage ride-through capability of SMES can be enhanced as well as its MW and MJ capacities. The distance relay is a key electrical apparatus that will trip circuit breakers to protect electrical devices from short circuit faults. Due to the application of SFCL and SMES integration, the voltage and current in power grid will change accordingly, and the operation characteristic of distance relay may be affected. In this paper, the impact of a bridge-type SFCL and SMES integration on the circle distance relay is studied. And simulation results show that the integration of SFCL and SMES does influence the measured impedance of distance relay, which can lead to mal-operation of the circle distance relay. Furthermore, an improved distance relay is proposed and verified.

  16. Fault current reduction by SFCL in a distribution system with PV using fuzzy logic technique

    Science.gov (United States)

    Mounika, M.; Lingareddy, P.

    2017-07-01

    In the modern power system, as the utilization of electric power is very wide, there is a frequent occurring of any fault or disturbance in power system. It causes a high short circuit current. Due to this fault, high currents occurs results to large mechanical forces, these forces cause overheating of the equipment. If the large size equipment are used in power system then they need a large protection scheme for severe fault conditions. Generally, the maintenance of electrical power system reliability is more important. But the elimination of fault is not possible in power systems. So the only alternate solution is to minimize the fault currents. For this the Super Conducting Fault Current Limiter using fuzzy logic technique is the best electric equipment which is used for reducing the severe fault current levels. In this paper, we simulated the unsymmetrical and symmetrical faults with fuzzy based superconducting fault current limiter. In our analysis it is proved that, fuzzy logic based super conducting fault current limiter reduces fault current quickly to a lower value.

  17. Performance test of the cryogenic cooling system for the superconducting fault current limiter

    Science.gov (United States)

    Hong, Yong-Ju; In, Sehwan; Yeom, Han-Kil; Kim, Heesun; Kim, Hye-Rim

    2015-12-01

    A Superconducting Fault Current Limiter is an electric power device which limits the fault current immediately in a power grid. The SFCL must be cooled to below the critical temperature of high temperature superconductor modules. In general, they are submerged in sub-cooled liquid nitrogen for their stable thermal characteristics. To cool and maintain the target temperature and pressure of the sub-cooled liquid nitrogen, the cryogenic cooling system should be designed well with a cryocooler and coolant circulation devices. The pressure of the cryostat for the SFCL should be pressurized to suppress the generation of nitrogen bubbles in quench mode of the SFCL. In this study, we tested the performance of the cooling system for the prototype 154 kV SFCL, which consist of a Stirling cryocooler, a subcooling cryostat, a pressure builder and a main cryostat for the SFCL module, to verify the design of the cooling system and the electric performance of the SFCL. The normal operation condition of the main cryostat is 71 K and 500 kPa. This paper presents tests results of the overall cooling system.

  18. A superconducting direct-current limiter with a power of up to 8 MVA

    Science.gov (United States)

    Fisher, L. M.; Alferov, D. F.; Akhmetgareev, M. R.; Budovskii, A. I.; Evsin, D. V.; Voloshin, I. F.; Kalinov, A. V.

    2016-12-01

    A resistive switching superconducting fault current limiter (SFCL) for DC networks with a nominal voltage of 3.5 kV and a nominal current of 2 kA was developed, produced, and tested. The SFCL has two main units—an assembly of superconducting modules and a high-speed vacuum circuit breaker. The assembly of superconducting modules consists of nine (3 × 3) parallel-series connected modules. Each module contains four parallel-connected 2G high-temperature superconducting (HTS) tapes. The results of SFCL tests in the short-circuit emulation mode with a maximum current rise rate of 1300 A/ms are presented. The SFCL is capable of limiting the current at a level of 7 kA and break it 8 ms after the current-limiting mode begins. The average temperature of HTS tapes during the current-limiting mode increases to 210 K. After the current is interrupted, the superconductivity recovery time does not exceed 1 s.

  19. Investigation of shunt resistor's connection for a DC Resistive SFCL

    Energy Technology Data Exchange (ETDEWEB)

    Imparato, S; Morandi, A; Fabbri, M; Negrini, F; Ribani, P L, E-mail: salvatore.imparato@mail.ing.unibo.i [Department of Electrical Engineering, University of Bologna, Viale Risorgimento 2, 40136 Bologna (Italy)

    2010-06-01

    A DC-operating resistive-type superconducting fault current limiter for AC applications (in short a DC Resistive SFCL) is based on the synergistic use of the 'resistive' and the 'rectifier' fault current limiter concepts, and allows the superconductor to operate in nearly DC current conditions. This regime of operation drastically reduces AC losses thus opening new perspectives with regard to materials, architecture of the cable, lay out of windings and cryogenics. In this paper the concept of DC resistive SFCL is resumed and a case study about its possible application in the distribution electrical system is reported. Two possible connections of external shunt resistor in order to reduce the Joule heating during the limiting phase are analysed.

  20. Implementation of superconducting fault current limiter for flexible operation in the power substation

    Energy Technology Data Exchange (ETDEWEB)

    Song, Chong Suk, E-mail: chong_suk@korea.ac.kr [School of Electrical Engineering, Korea University, Anam dong, Seonbukgu, Seoul 136-713 (Korea, Republic of); Lee, Hansang [School of Railway and Electrical Engineering, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Cho, Yoon-sung [Department of Electric and Energy Engineering, Catholic University of Daegu, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-702 (Korea, Republic of); Suh, Jaewan [School of Electrical Engineering, Korea University, Anam dong, Seonbukgu, Seoul 136-713 (Korea, Republic of); Jang, Gilsoo, E-mail: gjang@korea.ac.kr [School of Electrical Engineering, Korea University, Anam dong, Seonbukgu, Seoul 136-713 (Korea, Republic of)

    2014-09-15

    Highlights: • The power load concentrated in load centers results in high levels of fault current. • This paper introduces a fault current reduction scheme using SFCLs in substations. • The SFCL is connected in parallel to the bus tie between the two busbars. • The fault current mitigation using SFCLs is verified through PSS/e simulations. - Abstract: The concentration of large-scale power loads located in the metropolitan areas have resulted in high fault current levels during a fault thereby requiring the substation to operate in the double busbar configuration mode. However, the double busbar configuration mode results in deterioration of power system reliability and unbalanced power flow in the adjacent transmission lines which may result in issues such as overloading of lines. This paper proposes the implementation of the superconducting fault current limiter (SFCL) to be installed between the two substation busbars for a more efficient and flexible operation of the substation enabling both single and double busbar configurations depending on the system conditions for guaranteeing power system reliability as well as fault current limitations. Case studies are being performed for the effectiveness of the SFCL installation and results are compared for the cases where the substation is operating in single and double busbar mode and with and without the installation of the SFCL for fault current mitigation.

  1. Current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Loescher, D.H. [Sandia National Labs., Albuquerque, NM (United States). Systems Surety Assessment Dept.; Noren, K. [Univ. of Idaho, Moscow, ID (United States). Dept. of Electrical Engineering

    1996-09-01

    The current that flows between the electrical test equipment and the nuclear explosive must be limited to safe levels during electrical tests conducted on nuclear explosives at the DOE Pantex facility. The safest way to limit the current is to use batteries that can provide only acceptably low current into a short circuit; unfortunately this is not always possible. When it is not possible, current limiters, along with other design features, are used to limit the current. Three types of current limiters, the fuse blower, the resistor limiter, and the MOSFET-pass-transistor limiters, are used extensively in Pantex test equipment. Detailed failure mode and effects analyses were conducted on these limiters. Two other types of limiters were also analyzed. It was found that there is no best type of limiter that should be used in all applications. The fuse blower has advantages when many circuits must be monitored, a low insertion voltage drop is important, and size and weight must be kept low. However, this limiter has many failure modes that can lead to the loss of over current protection. The resistor limiter is simple and inexpensive, but is normally usable only on circuits for which the nominal current is less than a few tens of milliamperes. The MOSFET limiter can be used on high current circuits, but it has a number of single point failure modes that can lead to a loss of protective action. Because bad component placement or poor wire routing can defeat any limiter, placement and routing must be designed carefully and documented thoroughly.

  2. Comparative study of superconducting fault current limiter both for LCC-HVDC and VSC-HVDC systems

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong-Geon; Khan, Umer Amir; Lim, Sung-Woo; Shin, Woo-ju; Seo, In-Jin; Lee, Bang-Wook, E-mail: bangwook@hanyang.ac.kr

    2015-11-15

    Highlights: • The role of SFCL in types of HVDC system was evaluated. • A simulation model based on Korea Jeju–Haenam HVDC power system was designed in Matlab/Simulink. • Utilizing the designed both HVDC power system models, the efficiency of DC-SFCL was relatively low, compared to AC-SFCL. • It was deduced that the AC-SFCL was more effective in LCC-HVDC system than VSC-HVDC system. - Abstract: High Voltage Direct Current (HVDC) system has been evaluated as the optimum solution for the renewable energy transmission and long-distance power grid connections. In spite of the various advantages of HVDC system, it still has been regarded as an unreliable system compared to AC system due to its vulnerable characteristics on the power system fault. Furthermore, unlike AC system, optimum protection and switching device has not been fully developed yet. Therefore, in order to enhance the reliability of the HVDC systems mitigation of power system fault and reliable fault current limiting and switching devices should be developed. In this paper, in order to mitigate HVDC fault, both for Line Commutated Converter HVDC (LCC-HVDC) and Voltage Source Converter HVDC (VSC-HVDC) system, an application of resistive superconducting fault current limiter which has been known as optimum solution to cope with the power system fault was considered. Firstly, simulation models for two types of LCC-HVDC and VSC-HVDC system which has point to point connection model were developed. From the designed model, fault current characteristics of faulty condition were analyzed. Second, application of SFCL on each types of HVDC system and comparative study of modified fault current characteristics were analyzed. Consequently, it was deduced that an application of AC-SFCL on LCC-HVDC system with point to point connection was desirable solution to mitigate the fault current stresses and to prevent commutation failure in HVDC electric power system interconnected with AC grid.

  3. Mitigation of commutation failures in LCC-HVDC systems based on superconducting fault current limiters

    Science.gov (United States)

    Lee, Jong-Geon; Khan, Umer Amir; Lee, Ho-Yun; Lim, Sung-Woo; Lee, Bang-Wook

    2016-11-01

    Commutation failure in line commutated converter based HVDC systems cause severe damages on the entire power grid system. For LCC-HVDC, thyristor valves are turned on by a firing signal but turn off control is governed by the external applied AC voltage from surrounding network. When the fault occurs in AC system, turn-off control of thyristor valves is unavailable due to the voltage collapse of point of common coupling (PCC), which causes the commutation failure in LCC-HVDC link. Due to the commutation failure, the power transfer interruption, dc voltage drop and severe voltage fluctuation in the AC system could be occurred. In a severe situation, it might cause the protection system to block the valves. In this paper, as a solution to prevent the voltage collapse on PCC and to limit the fault current, the application study of resistive superconducting fault current limiter (SFCL) on LCC-HVDC grid system was performed with mathematical and simulation analyses. The simulation model was designed by Matlab/Simulink considering Haenam-Jeju HVDC power grid in Korea which includes conventional AC system and onshore wind farm and resistive SFCL model. From the result, it was observed that the application of SFCL on LCC-HVDC system is an effective solution to mitigate the commutation failure. And then the process to determine optimum quench resistance of SFCL which enables the recovery of commutation failure was deeply investigated.

  4. Mitigation of commutation failures in LCC–HVDC systems based on superconducting fault current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong-Geon; Khan, Umer Amir; Lee, Ho-Yun; Lim, Sung-Woo; Lee, Bang-Wook, E-mail: bangwook@hanyang.ac.kr

    2016-11-15

    Commutation failure in line commutated converter based HVDC systems cause severe damages on the entire power grid system. For LCC–HVDC, thyristor valves are turned on by a firing signal but turn off control is governed by the external applied AC voltage from surrounding network. When the fault occurs in AC system, turn-off control of thyristor valves is unavailable due to the voltage collapse of point of common coupling (PCC), which causes the commutation failure in LCC–HVDC link. Due to the commutation failure, the power transfer interruption, dc voltage drop and severe voltage fluctuation in the AC system could be occurred. In a severe situation, it might cause the protection system to block the valves. In this paper, as a solution to prevent the voltage collapse on PCC and to limit the fault current, the application study of resistive superconducting fault current limiter (SFCL) on LCC–HVDC grid system was performed with mathematical and simulation analyses. The simulation model was designed by Matlab/Simulink considering Haenam-Jeju HVDC power grid in Korea which includes conventional AC system and onshore wind farm and resistive SFCL model. From the result, it was observed that the application of SFCL on LCC–HVDC system is an effective solution to mitigate the commutation failure. And then the process to determine optimum quench resistance of SFCL which enables the recovery of commutation failure was deeply investigated.

  5. Application of a modified flux-coupling type superconducting fault current limiter to transient performance enhancement of micro-grid

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lei, E-mail: stclchen1982@163.com [School of Electrical Engineering, Wuhan University, Wuhan 430072 (China); Zheng, Feng; Deng, Changhong; Li, Shichun; Li, Miao; Liu, Hui [School of Electrical Engineering, Wuhan University, Wuhan 430072 (China); Zhu, Lin [Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville 37996 (United States); Guo, Fang [Department of Substation, Guang Dong Electric Power Design Institute, Guangzhou 510663 (China)

    2015-11-15

    Highlights: • A modified flux-coupling type SFCL is suggested to enhance the transient performance of a micro-grid. • The SFCL’s main contribution is to improve the micro-grid’s fault ride-through capability. • The SFCL also can make the micro-grid carry out a smooth transition between its grid-connected and islanded modes. • The simulations show that the SFCL can availably strengthen the micro-grid’s voltage and frequency stability. - Abstract: Concerning the application and development of a micro-grid system which is designed to accommodate high penetration of intermittent renewable resources, one of the main issues is related to an increase in the fault-current level. It is crucial to ensure the micro-grid’s operational stability and service reliability when a fault occurs in the main network. In this paper, our research group suggests a modified flux-coupling type superconducting fault current limiter (SFCL) to enhance the transient performance of a typical micro-grid system. The SFCL is installed at the point of common coupling (PCC) between the main network and the micro-grid, and it is expected to actively improve the micro-grid’s fault ride-through capability. And for some specific faults, the micro-grid should disconnect from the main network, and the SFCL’s contribution is to make the micro-grid carry out a smooth transition between its grid-connected and islanded modes. Related theory derivation, technical discussion and simulation analysis are performed. From the demonstrated results, applying the SFCL can effectively limit the fault current, maintain the power balance, and enhance the voltage and frequency stability of the micro-grid.

  6. Influences of Resistor-Type Superconducting Fault Current Limiter on Power System Transient Stability with Asymmetrical Short-Circuit Faults

    Institute of Scientific and Technical Information of China (English)

    Xue-Ping Gu; Zhi-Long Yang

    2008-01-01

    The transient stability of a single machine to infinite-busbar power system with resistor- type superconducting fault current limiters (SFCL) is analyzed under asymmetrical short-circuit fault conditions. The SFCL is considered to introduce a resistance into the three-phase circuits when faults occur. Based on the power-angle curves for different short-circuit conditions of the single-line to ground, double-line to ground and line to line short-circuit faults, the influences of the SFCLs on transient stability are analyzed in detail. The time-domain simulation of transient stability is carried out to verify the analytical results.

  7. A numerical study on the feasibility evaluation of a hybrid type superconducting fault current limiter applying thyristors

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Seok Ho; Lee, Woo Seung; Lee, Ji Ho; Hwang, Young Jin; Ko, Tae Kuk [Yonsei University, Seoul (Korea, Republic of)

    2013-12-15

    Smart fault current controller (SFCC) proposed in our previous work consists of a power converter, a high temperature superconducting (HTS) DC reactor, thyristors, and a control unit [1]. SFCC can limit and control the current by adjusting firing angles of thyristors when a fault occurs. SFCC has complex structure because the HTS DC reactor generates the loss under AC. To use the DC reactor under AC, rectifier that consists of four thyristors is needed and it increases internal resistance of SFCC. For this reason, authors propose a hybrid type superconducting fault current limiter (SFCL). The hybrid type SFCL proposed in this paper consists of a non-inductive superconducting coil and two thyristors. To verify the feasibility of the proposed hybrid type SFCL, simulations about the interaction of the superconducting coil and thyristors are conducted when fault current flows in the superconducting coil. Authors expect that the hybrid type SFCL can control the magnitude of the fault current by adjusting the firing angles of thyristors after the superconducting coil limits the fault current at first peak.

  8. Development, Testing and Installation of a Superconducting Fault Current Limiter for Medium Voltage Distribution Networks

    Science.gov (United States)

    Martini, Luciano; Bocchi, Marco; Ascade, Massimo; Valzasina, Angelo; Rossi, Valerio; Angeli, Giuliano; Ravetta, Cesare

    Since 2009 Ricerca sul Sistema Energetico (RSE S.p.A.) has been involved in the design of resistive-type Superconducting Fault Current Limiter (SFCL) for MV applications to be installed in the A2A Reti Elettriche S.p.A distribution grid in the Milano area. The project started with simulations, design and testing activities for a singlephase device; in this paper we report on the successive step, which is concerned with developing, testing and installation at the hosting utility of the final three-phase SFCL prototype. The result of this research activity is a resistive-type 9 kV/3.4 MVA SFCL device, based on first generation (1G) BSCCO tapes, developed by RSE in the framework of a R&D national project. Owing to the positive test results of partial discharge, dielectric and shortcircuit results the three-phase SFCL device is being to be installed in the A2A distribution grid in the Milano area and it is going to be soon energized starting a one-year long field-testing activity.

  9. Superconducting fault-current limiter and inductor design

    Science.gov (United States)

    Rogers, J. D.; Boenig, H. J.; Chowdhuri, P.; Schermer, R. I.; Wollan, J. J.; Weldon, D. M.

    1982-11-01

    A superconducting fault current limiter (SFCL) that uses a biased superconducting inductor in a diode or thyristor bridge circuit was analyzed for transmission systems in 69, 138, and 230 rms kV utility transmission systems. The limiter was evaluated for costs with all components, superconducting coil, diode and/or SCR power electronics, high voltage insulation, high voltage bushings and vapor cooled leads, dewar, and refrigerator, included. A design was undertaken for the superconducting cable and coils for both diode and SCR 69 kV limiter circuits.

  10. Super conducting fault current limiter and inductor design

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, J.; Boenig, H.; Chowdhuri, P.; Schermer, R.; Weldon, D.; Wollan, J.

    1983-05-01

    A superconducting fault current limiter (SFCL) that uses a biased superconducting inductor in a diode or thyristor bridge circuit was analyzed for transmission systems in 69, 138, and 230 rms kV utility transmission systems. The limiter was evaluated for costs with all components--superconducting coil, diode and/or SCR power electronics, high voltage insulation, high voltage bushings and vapor cooled leads, dewar, and refrigerator--included. A design was undertaken for the superconducting cable and coils for both diode and SCR 69 kV limiter circuits.

  11. Superconducting fault-current limiter and inductor design

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, J.D.; Boenig, H.J.; Chowdhuri, P.; Schermer, R.I.; Wollan, J.J.; Weldon, D.M.

    1982-01-01

    A superconducting fault current limiter (SFCL) that uses a biased superconducting inductor in a diode or thyristor bridge circuit was analyzed for transmission systems in 69, 138, and 230 rms kV utility transmission systems. The limiter was evaluated for costs with all components - superconducting coil, diode and/or SCR power electronics, high voltage insulation, high voltage bushings and vapor cooled leads, dewar, and refrigerator - included. A design was undertaken for the superconducting cable and coils for both diode and SCR 69 kV limiter circuits.

  12. Current limiting behavior in three-phase transformer-type SFCLs using an iron core according to variety of fault

    Science.gov (United States)

    Cho, Yong-Sun; Jung, Byung-Ik; Ha, Kyoung-Hun; Choi, Soo-Geun; Park, Hyoung-Min; Choi, Hyo-Sang

    To apply the superconducting fault current limiter (SFCL) to the power system, the reliability of the fault-current-limiting operation must be ensured in diverse fault conditions. The SFCL must also be linked to the operation of the high-speed recloser in the power system. In this study, a three-phase transformer-type SFCL, which has a neutral line to improve the simultaneous quench characteristics of superconducting elements, was manufactured to analyze the fault-current-limiting characteristic according to the single, double, and triple line-to-ground faults. The transformer-type SFCL, wherein three-phase windings are connected to one iron core, reduced the burden on the superconducting element as the superconducting element on the sound phase was also quenched in the case of the single line-to-ground fault. In the case of double or triple line-to-ground faults, the flux from the faulted phase winding was interlinked with other faulted or sound phase windings, and the fault-current-limiting rate decreased because the windings of three phases were inductively connected by one iron core.

  13. Control strategy for three-phase four-wire PWM converter of integrated voltage compensation type active SFCL

    Science.gov (United States)

    Chen, Lei; Tang, Yuejin; Shi, Jing; Li, Zhi; Ren, Li; Cheng, Shijie

    2010-02-01

    The integrated voltage compensation type active superconducting fault current limiter (SFCL) is composed of three air-core superconducting transformers and a three-phase four-wire PWM converter. In order to realize the current-limiting characteristics of the integrated active SFCL, it is needed to control the three-phase four-wire PWM converter flexibly and reasonably. Thereby, the control strategy for the converter is analyzed in this paper. In dq0 reference frame, the mathematical model of the converter is founded. The double-loop control strategy, consisting of voltage outer loop and current inner loop, is presented. Moreover, the voltage balance control for the split DC link capacitors is also considered. Using MATLAB, the simulation model of the integrated active SFCL is built. According to the simulation results, it is known that, the presented control strategy is feasible and valid, and the converter can work well under unsymmetrical and symmetrical fault conditions, and then the fault current can be limited quickly and effectively.

  14. Application of a modified flux-coupling type superconducting fault current limiter to transient performance enhancement of micro-grid

    Science.gov (United States)

    Chen, Lei; Zheng, Feng; Deng, Changhong; Li, Shichun; Li, Miao; Liu, Hui; Zhu, Lin; Guo, Fang

    2015-11-01

    Concerning the application and development of a micro-grid system which is designed to accommodate high penetration of intermittent renewable resources, one of the main issues is related to an increase in the fault-current level. It is crucial to ensure the micro-grid's operational stability and service reliability when a fault occurs in the main network. In this paper, our research group suggests a modified flux-coupling type superconducting fault current limiter (SFCL) to enhance the transient performance of a typical micro-grid system. The SFCL is installed at the point of common coupling (PCC) between the main network and the micro-grid, and it is expected to actively improve the micro-grid's fault ride-through capability. And for some specific faults, the micro-grid should disconnect from the main network, and the SFCL's contribution is to make the micro-grid carry out a smooth transition between its grid-connected and islanded modes. Related theory derivation, technical discussion and simulation analysis are performed. From the demonstrated results, applying the SFCL can effectively limit the fault current, maintain the power balance, and enhance the voltage and frequency stability of the micro-grid.

  15. Study on Recovery Performance of High Tc Superconducting Tapes for Resistive Type Superconducting Fault Current Limiter Applications

    Science.gov (United States)

    kar, Soumen; Kulkarni, Sandeep; Dixit, Manglesh; Singh, Kuwar Pal; Gupta, Alok; Balasubramanyam, P. V.; Sarangi, S. K.; Rao, V. V.

    Recent advances in reliable production of long length high temperature superconducting (HTS) tapes have resulted in commercial application of superconducting fault current limiters (SFCLs) in electrical utility networks. SFCL gives excellent technical performance when compared to conventional fault current limiters. The fast self-recovery from normal state to superconducting state immediately after the fault removal is an essential criterion for resistive type SFCL operation. In this paper, results on AC over-current testing of 1st generation (1G) Bi2223 tapes and 2nd generation (2G) YBCO coated conductors operating at 77 K are reported. From these results, the recovery time is estimated for different available HTS tapes in the market. The current limiting tests have also been performed to study the effective current limitation. Further, the recovery characteristics after the current limitation are quantitatively discussed for repetitive faults for different time intervals in the range of 100 ms to few seconds.

  16. Coordinated Control of Superconducting Fault Current Limiter and Superconducting Magnetic Energy Storage for Transient Performance Enhancement of Grid-Connected Photovoltaic Generation System

    Directory of Open Access Journals (Sweden)

    Lei Chen

    2017-01-01

    Full Text Available In regard to the rapid development of renewable energy sources, more and more photovoltaic (PV generation systems have been connected to main power networks, and it is critical to enhance their transient performance under short-circuit faults conditions. This paper proposes and studies the coordinated control of a flux-coupling-type superconducting fault current limiter (SFCL and a superconducting magnetic energy storage (SMES, to improve the fault ride through (FRT capability and smooth the power fluctuation of a grid-connected PV generation system. Theoretical analyses of the device structure, operating principle and control strategy are conducted, and a detailed simulation model of 100 kW class PV generation system is built in MATLAB/SIMULINK. During the simulations of the symmetrical and asymmetrical faults, the maximum power point tracking (MPPT control is disabled, and four different cases including without auxiliary, with SFCL, with SMES, and with SFCL-SMES, are compared. From the demonstrated results, the combination of without MPPT and with SFCL-SMES can more efficiently improve the point of common coupling (PCC voltage sag, inhibit the DC-link overvoltage and alleviate the power fluctuation. Finally, a preliminary parameter optimization method is suggested for the SFCL and the SMES, and it is helpful to promote their future application in the real PV projects.

  17. Study of recovery characteristics of 2nd generation HTS tapes with different stabilizers for resistive type superconducting fault current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Jie, E-mail: 1988725sheng@163.com; Zeng, Weina; Ma, Jun; Yao, Zhihao; Li, Zhuyong; Jin, Zhijian; Hong, Zhiyong

    2016-02-15

    Highlights: • Three methods of measuring the recovery time of HTS tapes are compared. • Four tapes with different stabilizers were tested to compare their recovery characteristics. • The HTS tapes with thinner stabilizers have better recovery characteristics. • Encapsulation makes the recovery characteristics of HTS tapes worse. • The results can be reference of the re-reclosed operation time interval. - Abstract: The resistive type superconducting fault current limiter (SFCL) is one of the most important superconducting power applications nowadays. As known, this type of SFCL is settled directly in the power transmission line. When a short fault happens, the temperature of the superconductors in the SFCL will increase sharply due to the huge generated heat. This means the superconductors need time to recover the superconducting properties and be ready for the next short fault. So the recovery characteristics become one of the most crucial features of the resistive type SFCL. In this paper, several different kinds of measuring methods are presented to calculate the recovery time of the HTS tapes, and comparison of these methods is also carried out by a standard test. On basis of this, samples with different kinds of stabilizers are used to explore the influence of stabilizer on their recovery characteristics. In addition, the influence of the encapsulation technology is also discussed in this paper.

  18. The first Italian Superconducting Fault Current Limiter: Results of the field testing experience after one year operation

    Science.gov (United States)

    Martini, L.; Bocchi, M.; Ascade, M.; Valzasina, A.; Rossi, V.; Ravetta, C.; Angeli, G.

    2014-05-01

    Ricerca sul Sistema Energetico S.p.A. (RSE) has been gaining a relevant experience in the simulation, design and installation of resistive-type Superconducting Fault Current Limiter (SFCL) devices for more than five years in the framework of a R&D national project funded by the Ricerca di Sistema (RdS). The most recent outcome of this research activity is the installation of a resistive-type BSCCO-based 9 kV / 3.4 MVA SFCL device in a single feeder branch of the Medium Voltage (MV) distribution network managed by A2A Reti Elettriche S.p.A (A2A) in the Milano area. This installation represents the first SFCL successfully installed in Italy. In this paper, we report on the main outcomes after a more than 1-year long steady-state field testing activity. The design of an upgraded device to be installed in the same substation has already been initiated: the new SFCL will allow to protect four different feeders, therefore implying a device upgrade up to 15.6 MVA.

  19. Operating characteristics of superconducting fault current limiter using 24kV vacuum interrupter driven by electromagnetic repulsion switch

    Energy Technology Data Exchange (ETDEWEB)

    Endo, M; Hori, T; Koyama, K; Kaiho, K; Yanabu, S [Tokyo Denki University, 2-2 Kandanishiki-chou Chiyoda-ku Tokyo 101-8457 (Japan); Yamaguchi, I; Arai, K [National Institute of Advanced Industrial Science and Technology(AIST), 1-1-1 Umezono, Tsukuba-shi, Ibaraki 305-8565 (Japan)], E-mail: yanabu@e.dendai.ac.jp

    2008-02-01

    Using a high temperature superconductor, we constructed and tested a model Superconducting Fault Current Limiter (SFCL). SFCL which has a vacuum interrupter with electromagnetic repulsion mechanism. We set out to construct high voltage class SFCL. We produced the electromagnetic repulsion switch equipped with a 24kV vacuum interrupter(VI). There are problems that opening speed becomes late. Because the larger vacuum interrupter the heavier weight of its contact. For this reason, the current which flows in a superconductor may be unable to be interrupted within a half cycles of current. In order to solve this problem, it is necessary to change the design of the coil connected in parallel and to strengthen the electromagnetic repulsion force at the time of opening the vacuum interrupter. Then, the design of the coil was changed, and in order to examine whether the problem is solvable, the current limiting test was conducted. We examined current limiting test using 4 series and 2 parallel-connected YBCO thin films. We used 12-centimeter-long YBCO thin film. The parallel resistance (0.1{omega}) is connected with each YBCO thin film. As a result, we succeed in interrupting the current of superconductor within a half cycle of it. Furthermore, series and parallel-connected YBCO thin film could limit without failure.

  20. Implementation of an Effective Fault Current Limiter for 1.5 MW DFIG in Wind Power Systems

    Directory of Open Access Journals (Sweden)

    M. Panneerselvam

    2014-05-01

    Full Text Available With the continuous increase of power demand, the capacities of renewable energy generation systems are being expanded. With the increased penetration of wind energy as a renewable energy source, there is a need to keep wind turbines connected to the grid during grid faults. The ability of WTGS (Wind Turbine Generation System to remain connected to the grid during faults is termed as Fault-Ride Through capability (FRT of the system. In this paper, the use of superconducting fault current limiter (SFCL is proposed to improve the FRT capability of WTGS thus improving reliability of the system. A Doubly-Fed Induction Generator (DFIG is considered as a wind-turbine generator for analysis. Detailed simulation results are obtained with and without SFCL considering the stator and rotor currents. Also, the voltage profile, real and reactive power magnitudes are analyzed. The computed results ensure that SFCL is effective in mitigating the fault current magnitude which would enhance the reliability and stability of the system as a whole.

  1. Multi-scale model of resistive-type superconducting fault current limiters based on 2G HTS coated conductors

    Science.gov (United States)

    Bonnard, Charles-Henri; Sirois, Frédéric; Lacroix, Christian; Didier, Gaëtan

    2017-01-01

    In order to plan the integration of superconducting fault current limiters (SFCLs) in power systems, accurate models of SFCLs must be made available in commercial power system transient simulators. In this context, we developed such a model for the EMTP-RV software package, a power system transient simulator widely used by power utilities. The model can be used with any resistive-type SFCL (rSFCL) made of high temperature superconductor (HTS) tapes, which are discretized in ‘electro-thermal elements’. Those elements consist solely of electric circuit components, and are used to represent portions of tape of various sizes and dimensions (a ‘multi-scale’ approach). Both the electrical and thermal behaviors of the tape are modeled, including interfacial effects, nonlinear properties of materials and heat transfer to the surrounding environment. Such a multi-scale model can simulate accurately both the local quench dynamics of HTS tapes (microscopic scale) and the global impact of the rSFCL on the power system (macroscopic/system scale). In this paper, the model is used to compute phenomena such as propagation velocity of a hot spot and heat diffusion through the thickness of the tape. Results were verified by comparing EMTP-RV results with finite element simulations. In addition to the development of the multi-scale model itself, which is the major contribution of this paper, the use of the model allowed us to determine the conditions of validity of the commonly used ‘homogenization’ of the thermal properties across the tape thickness. Indeed, when the current flowing into the rSFCL is slightly above its critical current I c (and up to 2{I}{{c}}), very important errors in the power waveforms arise, leading to potentially wrong decisions of protection systems. Homogenized thermal models should thus be used with great care in practice.

  2. Thermal analysis of HTS air-core transformer used in voltage compensation type active SFCL

    Science.gov (United States)

    Song, M.; Tang, Y.; Li, J.; Zhou, Y.; Chen, L.; Ren, L.

    2010-11-01

    The three-phase voltage compensation type active superconducting fault current limiter (SFCL) is composed of three HTS air-core transformers and a three-phase four-wire Pulse Width Modulation (PWM) converter. The primary winding of the each phase HTS air-core transformer is in series with the main system, and the second winding is connected with the PWM converter. The single-phase conduction-cooled HTS air-core transformer is consisting of four double-pancakes wound by the Bi2223/Ag tape. In this paper, according to the electromagnetic analysis on the single-phase HTS air-core transformer, its AC loss corresponding to different operation modes is calculated. Furthermore, the thermal behaviors are studied by the time-stepping numerical simulations. On the basis of the simulation results, the related problems with the HTS air-core transformer's thermal stability are discussed.

  3. Current limiter circuit system

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. Comparative study of superconducting fault current limiter both for LCC-HVDC and VSC-HVDC systems

    Science.gov (United States)

    Lee, Jong-Geon; Khan, Umer Amir; Lim, Sung-Woo; Shin, Woo-ju; Seo, In-Jin; Lee, Bang-Wook

    2015-11-01

    High Voltage Direct Current (HVDC) system has been evaluated as the optimum solution for the renewable energy transmission and long-distance power grid connections. In spite of the various advantages of HVDC system, it still has been regarded as an unreliable system compared to AC system due to its vulnerable characteristics on the power system fault. Furthermore, unlike AC system, optimum protection and switching device has not been fully developed yet. Therefore, in order to enhance the reliability of the HVDC systems mitigation of power system fault and reliable fault current limiting and switching devices should be developed. In this paper, in order to mitigate HVDC fault, both for Line Commutated Converter HVDC (LCC-HVDC) and Voltage Source Converter HVDC (VSC-HVDC) system, an application of resistive superconducting fault current limiter which has been known as optimum solution to cope with the power system fault was considered. Firstly, simulation models for two types of LCC-HVDC and VSC-HVDC system which has point to point connection model were developed. From the designed model, fault current characteristics of faulty condition were analyzed. Second, application of SFCL on each types of HVDC system and comparative study of modified fault current characteristics were analyzed. Consequently, it was deduced that an application of AC-SFCL on LCC-HVDC system with point to point connection was desirable solution to mitigate the fault current stresses and to prevent commutation failure in HVDC electric power system interconnected with AC grid.

  5. Conceptual design of a high-speed electromagnetic switch for a modified flux-coupling-type SFCL and its application in renewable energy system.

    Science.gov (United States)

    Chen, Lei; Chen, Hongkun; Yang, Jun; Shu, Zhengyu; He, Huiwen; Shu, Xin

    2016-01-01

    The modified flux-coupling-type superconducting fault current (SFCL) is a high-efficient electrical auxiliary device, whose basic function is to suppress the short-circuit current by controlling the magnetic path through a high-speed switch. In this paper, the high-speed switch is based on electromagnetic repulsion mechanism, and its conceptual design is carried out to promote the application of the modified SFCL. Regarding that the switch which is consisting of a mobile copper disc, two fixed opening and closing coils, the computational method for the electromagnetic force is discussed, and also the dynamic mathematical model including circuit equation, magnetic field equation as well as mechanical motion equation is theoretically deduced. According to the mathematical modeling and calculation of characteristic parameters, a feasible design scheme is presented, and the high-speed switch's response time can be less than 0.5 ms. For that the modified SFCL is equipped with this high-speed switch, the SFCL's application in a 10 kV micro-grid system with multiple renewable energy sources are assessed in the MATLAB software. The simulations are well able to affirm the SFCL's performance behaviors.

  6. Superconducting technology for overcurrent limiting in a 25 kA current injection system

    Science.gov (United States)

    Heydari, Hossein; Faghihi, Faramarz; Sharifi, Reza; Poursoltanmohammadi, Amir Hossein

    2008-09-01

    Current injection transformer (CIT) systems are within the major group of the standard type test of high current equipment in the electrical industry, so their performance becomes very important. When designing high current systems, there are many factors to be considered from which their overcurrent protection must be ensured. The output of a CIT is wholly dependent on the impedance of the equipment under test (EUT). Therefore current flow beyond the allowable limit can occur. The present state of the art provides an important guide to developing current limiters not only for the grid application but also in industrial equipment. This paper reports the state of the art in the technology available that could be developed into an application of superconductivity for high current equipment (CIT) protection with no test disruption. This will result in a greater market choice and lower costs for equipment protection solutions, reduced costs and improved system reliability. The paper will also push the state of the art by using two distinctive circuits, closed-core and open-core, for overcurrent protection of a 25 kA CIT system, based on a flux-lock-type superconducting fault current limiter (SFCL) and magnetic properties of high temperature superconducting (HTS) elements. An appropriate location of the HTS element will enhance the rate of limitation with the help of the magnetic field generated by the CIT output busbars. The calculation of the HTS parameters for overcurrent limiting is also performed to suit the required current levels of the CIT.

  7. Technical Evaluation of Superconducting Fault Current Limiters Used in a Micro-Grid by Considering the Fault Characteristics of Distributed Generation, Energy Storage and Power Loads

    Directory of Open Access Journals (Sweden)

    Lei Chen

    2016-09-01

    Full Text Available Concerning the development of a micro-grid integrated with multiple intermittent renewable energy resources, one of the main issues is related to the improvement of its robustness against short-circuit faults. In a sense, the superconducting fault current limiter (SFCL can be regarded as a feasible approach to enhance the transient performance of a micro-grid under fault conditions. In this paper, the fault transient analysis of a micro-grid, including distributed generation, energy storage and power loads, is conducted, and regarding the application of one or more flux-coupling-type SFCLs in the micro-grid, an integrated technical evaluation method considering current-limiting performance, bus voltage stability and device cost is proposed. In order to assess the performance of the SFCLs and verify the effectiveness of the evaluation method, different fault cases of a 10-kV micro-grid with photovoltaic (PV, wind generator and energy storage are simulated in the MATLAB software. The results show that, the efficient use of the SFCLs for the micro-grid can contribute to reducing the fault current, improving the voltage sags and suppressing the frequency fluctuations. Moreover, there will be a compromise design to fully take advantage of the SFCL parameters, and thus, the transient performance of the micro-grid can be guaranteed.

  8. Active inrush-current limiter

    Science.gov (United States)

    Kichak, R. A.

    1977-01-01

    By stretching turn-on time from approximately 1 to 200 ms, effects of inrush current (and of associated large current spikes) and current rate of rise (dl/dt) are made potentially less severe. Limiter arrangement consists of time-variable impedance connected in series between input dc power source return and power circuit of converter.

  9. Application of fault current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, A.

    2007-11-30

    This report presents the results of a study commissioned by the Department for Business, Enterprise and Industry (BERR; formerly the Department of Trade and Industry) into the application of fault current limiters in the UK. The study reviewed the current state of fault current limiter (FCL) technology and regulatory position in relation to all types of current limiters. It identified significant research and development work with respect to medium voltage FCLs and a move to high voltage. Appropriate FCL technologies being developed include: solid state breakers; superconducting FCLs (including superconducting transformers); magnetic FCLs; and active network controllers. Commercialisation of these products depends on successful field tests and experience, plus material development in the case of high temperature superconducting FCL technologies. The report describes FCL techniques, the current state of FCL technologies, practical applications and future outlook for FCL technologies, distribution fault level analysis and an outline methodology for assessing the materiality of the fault level problem. A roadmap is presented that provides an 'action agenda' to advance the fault level issues associated with low carbon networks.

  10. Fault current limiters using superconductors

    Science.gov (United States)

    Norris, W. T.; Power, A.

    Fault current limiters on power systems are to reduce damage by heating and electromechanical forces, to alleviate duty on switchgear used to clear the fault, and to mitigate disturbance to unfaulted parts of the system. A basic scheme involves a super-resistor which is a superconductor being driven to high resistance when fault current flows either when current is high during a cycle of a.c. or, if the temperature of the superconductive material rises, for the full cycle. Current may be commuted from superconductor to an impedance in parallel, thus reducing the energy dispersed at low temperature and saving refrigeration. In a super-shorted transformer the ambient temperature primary carries the power system current; the superconductive secondary goes to a resistive condition when excessive currents flow in the primary. A super-transformer has the advantage of not needing current leads from high temperature to low temperature; it behaves as a parallel super-resistor and inductor. The supertransductor with a superconductive d.c. bias winding is large and has small effect on the rate of fall of current at current zero; it does little to alleviate duty on switchgear but does reduce heating and electromechanical forces. It is fully active after a fault has been cleared. Other schemes depend on rapid recooling of the superconductor to achieve this.

  11. 饱和铁芯型超导限流器研究进展综述%Summarization of R&D on DC biased iron core type superconductive fault current limiter

    Institute of Scientific and Technical Information of China (English)

    金涛; 徐颖; 周世平; 何清; 任丽

    2013-01-01

    电力系统短路电流对系统的稳定安全运行造成了极大的威胁,超导故障限流器是一种将超导技术、电力技术相结合产生的故障限流装置,能有效地限制短路电流.饱和铁芯型超导限流器是产业化前景较好的一种超导限流器,在对此类型的故障限流器进行了深入调研和广泛收集资料的基础上,介绍了饱和铁芯型超导限流器的工作原理,分析了它的优缺点,阐述了饱和铁芯型超导限流器的国内外发展现状,归纳了其在设计过程中的关键技术和制约其工业化应用的主要问题,并提出了技术建议,最后展望了饱和铁芯型超导限流的应用前景.%The continuous enlargement of fault current has great influence on the stability and safety of power system. Super-conductive Fault Current Limiter (SFCL) is a current - limiting device which combines the superconducting technology with the electric technology, which is a effective way to solve the problem. And DC biased iron core type SFCL has the better application prospect. According to the investigation and extensive collection of fundamental data, the operating principle of this type SFCL was introduced in this paper. Through analyzing the research and development situation at home and abroad, its advantages and disadvantages were compared. The key technologies in design procedure and main problems constraining its industrial application were summarized. Finally, technical proposal of the DC biased iron core type SFCL was proposed, and the application prospect of it was predicted.

  12. DC superconducting fault current limiter

    Science.gov (United States)

    Tixador, P.; Villard, C.; Cointe, Y.

    2006-03-01

    There is a lack of satisfying solutions for fault currents using conventional technologies, especially in DC networks, where a superconducting fault current limiter could play a very important part. DC networks bring a lot of advantages when compared to traditional AC ones, in particular within the context of the liberalization of the electric market. Under normal operation in a DC network, the losses in the superconducting element are nearly zero and only a small, i.e. a low cost, refrigeration system is then required. The absence of zero crossing of a DC fault current favourably accelerates the normal zone propagation. The very high current slope at the time of the short circuit in a DC grid is another favourable parameter. The material used for the experiments is YBCO deposited on Al2O3 as well as YBCO coated conductors. The DC limitation experiments are compared to AC ones at different frequencies (50-2000 Hz). Careful attention is paid to the quench homogenization, which is one of the key issues for an SC FCL. The University of Geneva has proposed constrictions. We have investigated an operating temperature higher than 77 K. As for YBCO bulk, an operation closer to the critical temperature brings a highly improved homogeneity in the electric field development. The material can then absorb large energies without degradation. We present tests at various temperatures. These promising results are to be confirmed over long lengths.

  13. State of the art of superconducting fault current limiters and their application to the electric power system

    Science.gov (United States)

    Morandi, Antonio

    2013-01-01

    Modern electric power systems are becoming more and more complex in order to meet new needs. Nowadays a high power quality is mandatory and there is the need to integrate increasing amounts of on-site generation. All this translates in more sophisticated electric network with intrinsically high short circuit rate. This network is vulnerable in case of fault and special protection apparatus and procedures needs to be developed in order to avoid costly or even irreversible damage. A superconducting fault current limiter (SFCL) is a device with a negligible impedance in normal operating conditions that reliably switches to a high impedance state in case of extra-current. Such a device is able to increase the short circuit power of an electric network and to contemporarily eliminate the hazard during the fault. It can be regarded as a key component for future electric power systems. In this paper the state of the art of superconducting fault current limiters mature for applications is briefly resumed and the potential impact of this device on the paradigm of design and operation of power systems is analyzed. In particular the use of the FCL as a mean to allow more interconnection of MV bus-bars as well an increased immunity with respect to the voltage disturbances induced by critical customer is discussed. The possibility to integrate more distributed generation in the distribution grid is also considered.

  14. Research on resistance characteristics of YBCO tape under short-time DC large current impact

    Science.gov (United States)

    Zhang, Zhifeng; Yang, Jiabin; Qiu, Qingquan; Zhang, Guomin; Lin, Liangzhen

    2017-06-01

    Research of the resistance characteristics of YBCO tape under short-time DC large current impact is the foundation of the developing DC superconducting fault current limiter (SFCL) for voltage source converter-based high voltage direct current system (VSC-HVDC), which is one of the valid approaches to solve the problems of renewable energy integration. SFCL can limit DC short-circuit and enhance the interrupting capabilities of DC circuit breakers. In this paper, under short-time DC large current impacts, the resistance features of naked tape of YBCO tape are studied to find the resistance - temperature change rule and the maximum impact current. The influence of insulation for the resistance - temperature characteristics of YBCO tape is studied by comparison tests with naked tape and insulating tape in 77 K. The influence of operating temperature on the tape is also studied under subcooled liquid nitrogen condition. For the current impact security of YBCO tape, the critical current degradation and top temperature are analyzed and worked as judgment standards. The testing results is helpful for in developing SFCL in VSC-HVDC.

  15. High temperature superconducting fault current limiter

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R. (Hinsdale, IL)

    1997-01-01

    A fault current limiter (10) for an electrical circuit (14). The fault current limiter (10) includes a high temperature superconductor (12) in the electrical circuit (14). The high temperature superconductor (12) is cooled below its critical temperature to maintain the superconducting electrical properties during operation as the fault current limiter (10).

  16. Fault current limiter using bulk oxides superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Belmont, O.; Ferracci, P.; Porcar, L.; Barbut, J.M. [Schneider Electric, Grenoble (France). Usine A3; Tixador, P.; Noudem, J.G.; Bourgault, D.; Tournier, R

    1998-08-01

    We study the limitation possibilities of bulk Bi high T{sub c} materials. For this we test these materials with AC or DC currents above their critical currents. We study particularly the evolution of the voltage with time or with current. The material, the value of the current and the time duration play important parts. For sintered Bi samples the voltage depends only on the current even for values much larger than the critical current. With textured samples the V(I) curves shows an hysteretic behaviour due to a warming up. The textured materials are more interesting than sintered ones in terms of required volume for the current limitation. In both cases the superconductors are in a dissipative state but not in the normal state. This state is nevertheless reached if the dissipated energy inside the sample is sufficient. We have tried to apply a magnetic field on the samples in order to trigger a more effective limitation. The voltage increases but with a limited effect for currents much higher (3-4 times) than the critical zero field current. We think that the dissipative state is due mainly to the grain boundaries which become resistive above the critical current. (orig.) 11 refs.

  17. Current limiting remote power control module

    Science.gov (United States)

    Hopkins, Douglas C.

    1990-01-01

    The power source for the Space Station Freedom will be fully utilized nearly all of the time. As such, any loads on the system will need to operate within expected limits. Should any load draw an inordinate amount of power, the bus voltage for the system may sag and disrupt the operation of other loads. To protect the bus and loads some type of power interface between the bus and each load must be provided. This interface is most crucial when load faults occur. A possible system configuration is presented. The proposed interface is the Current Limiting Remote Power Controller (CL-RPC). Such an interface should provide the following power functions: limit overloading and resulting undervoltage; prevent catastrophic failure and still provide for redundancy management within the load; minimize cable heating; and provide accurate current measurement. A functional block diagram of the power processing stage of a CL-RPC is included. There are four functions that drive the circuit design: rate control of current; current sensing; the variable conductance switch (VCS) technology; and the algorithm used for current limiting. Each function is discussed separately.

  18. Superconducting Fault Current Limiter optimized design

    Energy Technology Data Exchange (ETDEWEB)

    Tixador, Pascal, E-mail: Pascal.Tixador@grenoble-inp.fr [Univ. Grenoble Alpes, G2Elab – Institut Néel, F-38000 Grenoble (France); CNRS, G2Elab – Institut Néel, F-38000 Grenoble (France); Badel, Arnaud [CNRS, G2Elab – Institut Néel, F-38000 Grenoble (France)

    2015-11-15

    Highlights: • A low cost design of YBCO Fault Current Limiter. • A high resistance conductor for reduced length. • An asymmetrical YBCO conductor (injection and AC losses). • A thickness suitable for non destructive hot spots. - Abstract: The SuperConducting Fault Current Limiter (SCFCL) appears as one of the most promising SC applications for the electrical grids. Despite its advantages and many successful field experiences the market of SCFCL has difficulties to take off even if the first orders for permanent operation in grids are taken. The analytical design of resistive SCFCL will be discussed with the objective to reduce the quantity of SC conductor (length and section) to be more cost-effective. For that the SC conductor must have a high resistivity in normal state. It can be achieved by using high resistivity alloy for shunt, such as Hastelloy®. One of the most severe constraint is that the SCFCL should operate safely for any faults, especially those with low prospective short-circuit currents. This constraint requires to properly design the thickness of the SC tape in order to limit the hot spot temperature. An operation at 65 K appears as very interesting since it decreases the SC cost at least by a factor 2 with a simple LN2 cryogenics. Taking into account the cost reduction in a near future, the SC conductor cost could be rather low, half a dollar per kV A.

  19. Novel 3-Phase Inductive Fault Current Limiter

    Science.gov (United States)

    Kosa, Janos

    The paper describes the inductive three-phase fault current limiter. In this work I examine the novel arrangements of the perfect closed superconducting loop made of HTS wire. I applied one iron core with 3 limbs and special loops for uniform temperature of the superconducting wire. In this work I present the results of my experiments with this device. I present the static and dynamic measured results of this solution. It has got several advantages e. g. fast switching and less fault power for high-power electric machines. The advantage of the equipment is that in the case of single-phase short circuit the current will decrease in all the three phases. This can be an appropriate solution for high power machines. For example, in the case of high-power electric motor if there is a single-phase breaking or a single phase short circuit, we can decrease the current in the three phases.

  20. Superconducting Fault Current Limiter optimized design

    Science.gov (United States)

    Tixador, Pascal; Badel, Arnaud

    2015-11-01

    The SuperConducting Fault Current Limiter (SCFCL) appears as one of the most promising SC applications for the electrical grids. Despite its advantages and many successful field experiences the market of SCFCL has difficulties to take off even if the first orders for permanent operation in grids are taken. The analytical design of resistive SCFCL will be discussed with the objective to reduce the quantity of SC conductor (length and section) to be more cost-effective. For that the SC conductor must have a high resistivity in normal state. It can be achieved by using high resistivity alloy for shunt, such as Hastelloy®. One of the most severe constraint is that the SCFCL should operate safely for any faults, especially those with low prospective short-circuit currents. This constraint requires to properly design the thickness of the SC tape in order to limit the hot spot temperature. An operation at 65 K appears as very interesting since it decreases the SC cost at least by a factor 2 with a simple LN2 cryogenics. Taking into account the cost reduction in a near future, the SC conductor cost could be rather low, half a dollar per kV A.

  1. Current limiting level-time characteristic of a superconducting fault current limiter

    Science.gov (United States)

    Tang, Y. J.; Yokomizu, Y.; Hayakawa, N.; Matsumura, T.; Okubo, H.; Kito, Y.

    A model superconducting fault current limiter (SE-FCL) has been developed. The adopted superconducting cable is composed of six strands insulated from each other. The current limiting level of the SC-FCL is measured under two types of overcurrent, a sinusoidal and an inrush current. The results show that the current limiting level of the SC-FCL Iq increases with an increase in the rate of rise of the overcurrent. By introducing a new parameter of time-to-quench tf, it is found that Iq increases with decreasing tf. This feature is taken as a current limiting level-time characteristic i.e. the Iq- tf characteristic. The existence of the Iq- tf characteristic found in the SC-FCL is qualitatively explained by measuring current distribution among the six strands. The superconducting cable is driven to the normal state strand by strand. Some delay in time is found from the quench of the first strand to that of the last and this is recognized as an Iq- tf characteristic in its current limiting performance.

  2. Application of Superconducting Fault Current Limiters in Resolving Short-Circuit Currents in Power Grids%超导限流器在解决电网短路电流中的应用分析

    Institute of Scientific and Technical Information of China (English)

    舒彬; 陈志莉; 任安林; 信赢

    2012-01-01

    Superconducting Fault Current Limiter (SFCL) has superior properties as a new fault current limiting device. SFCLs are able to contribute significantly to the solution to fault current problem. This paper discusses the demands and challenges in the application of SFCLs to power grids. Technical and economical comparisons with conventional fault current control technologies are presented. Finally the marketing path of SFCLs is analyzed. The 220 kV SFCLs promise better technical & economic benefits and they represent an important breakthrough in promoting the application of SFCLs. With further technological development and cost reduction, they may finally be applied to 500 kV power grids and MV networks with DGs.%作为一种新型限流设备,超导限流器以其优越的特性,将在解决短路电流问题上发挥重要作用.讨论了不同电压等级电网对超导限流器的应用需求及设计要求,并通过与传统方案的技术经济比较,分析了其市场发展路径.220 kV级SFCI将以其综合技术经济优势打开应用的突破口,随着技术不断提高及成本降低,将在500 kV电网和分布式配电网中得到广泛应用.

  3. Inrush-Current Limiter And Bus Isolator

    Science.gov (United States)

    Dolland, Carlisle R.

    1994-01-01

    Electronic circuit protects electrical power bus and source of power against excessive current demands. Circuit intended for use with power-consuming electronic system drawing pulsed currents and including capacitor bank as low-impedance secondary source from which pulsed currents drawn.

  4. Medicare Current Beneficiary Survey - Limited Data Set

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Medicare Current Beneficiary Survey (MCBS) is a continuous, multipurpose survey of a representative national sample of the Medicare population. There are two...

  5. Influence of Superconductor Fault Current Limiter on Transformers Lifetime

    Directory of Open Access Journals (Sweden)

    2012-07-01

    Full Text Available In this article the impact of the superconducting current limiter and reducing the incidenceof stress single phase short circuit has been analyzed with this method and conventionalmethod of current limiting resistance has been compared. For this purpose a saturated corehigh temperature superconducting current limiter model considered and its effects on networkperformance in different modes has been studied. PSCAD software for simulating thenetwork is used.

  6. Natural Limits for Currents in Charge Separated Pulsar Magnetospheres

    CERN Document Server

    Jessner, A; Kunzl, T A

    2002-01-01

    Rough estimates and upper limits on current and particle densities form the basis of most of the canonical pulsar models. Whereas the surface of the rotating neutron star is capable of supplying sufficient charges to provide a current that, given the polar cap potential, could easily fuel the observed energy loss processes, observational and theoretical constraints provide strict upper limits to the charge densities. The space charge of a current consisting solely of particles having only one sign creates a compensating potential that will make the maximum current dependent on potential and distance. In the non-relativistic case this fact is expressed in the familiar Child-Langmuir law. Its relativistic generalization and subsequent application to the inner pulsar magnetosphere provides clear limits on the strength and radial extension of charged currents originating on the polar cap. Violent Pierce-type oscillations set in, if one attempts to inject more current than the space charge limit into a given volum...

  7. Limiting the current with HTc materials; HTc pour la limitation du courant

    Energy Technology Data Exchange (ETDEWEB)

    Barbut, J.M.; Belmont, O.; Devismes, M.F.; Noudem, J.G.; Porcar, L.; Sanchez, J. [Schneider Electric, Grenoble (France); Tixador, P. [CRTBT, CNRS, Grenoble (France); Bourgault, D.; Tournier, R. [Matformag, CNRS, Grenoble (France)

    1998-01-01

    Superconducting fault current limiter could be used in high voltage network. A most part of existing HTc superconducting materials have been tested in situation to limit fault current. Bulk materials are classified by growing critical current density which correspond to different behaviours. Critical electrical field during transition seems to be about 1 kV/m. (orig.). 7 refs.

  8. Vacuum Dielectric Recovery Characteristics of a Novel Current Limiting Circuit Breaker Base on Artificial Current Zero

    Institute of Scientific and Technical Information of China (English)

    JIANG Zhuangxian; ZHUANG Jinwu; WANG Chen; WU Jin; LIU Luhui

    2012-01-01

    A novel current limiting circuit breaker employs zero current switching method in cutting off DC current, which gives out a reverse impulsive current towards a high speed vacuum interrupter and force the current down to zero. This kind of breaker is simply in structure and can act in a very short time with high current limiting capability, and therefore it has a long electric life and is extremely suitable to be installed in a DC electrical system as a fault orotection utility.

  9. Space-charge limiting current in spherical cathode diodes

    Institute of Scientific and Technical Information of China (English)

    刘国治; 邵浩

    2003-01-01

    The results of the investigation on the space-charge limiting current for a spherical-cathode diode in the nonrelativistic situation are presented in this paper. The results show that the current enhancement factor equals the square of E-field enhancement factor on the cathode surface. The generated space-charge limiting current is deduced.In the case of a pin-shaped-cathode diode, the space-charge limiting current is also obtained, indicating that the current is independent of the geometric parameters of the diode. Analyses of the shielding effects and the conditions for generation of the uniform space-charge limiting beam show that, for pin-arrayed cathodes, the distance between pins should be in the range from 1.2D to 1.5D, where D is the distance between the two electrodes.

  10. Geometry dependence of 2-dimensional space-charge-limited currents

    CERN Document Server

    De Visschere, Patrick

    2016-01-01

    The space-charge-limited current in a zero thickness planar thin film depends on the geometry of the electrodes. We present a theory which is to a large extent analytical and applicable to many different lay-outs. We show that a space-charge-limited current can only be sustained if the emitting electrode induces a singularity in the field and if the singularity induced by the collecting electrode is not too strong. For those lay-outs where no space-charge-limited current can be sustained for a zero thickness film, the real thickness of the film must be taken into account using a numerical model.

  11. Fault Current Limitation with Superconducting YBCO Thin Films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The behavior of YBCO/metal bilayers under transport currents was explored in the framework of fault current limitation (FCL). Properties of the superconducting-normal transition were first studied phenomenologically during sweep current experiments. For current rates higher than 500 A/s, the transition into the normal state was based on non-thermal phenomena and was characterized by a flux creep regime ended by a jump into the normal state. At lower sweep rates, a total diversion of the current in the metallic shunt was observed for temperatures higher than 85 K. In this regime, a partial recovery of the superconducting state took place due to a finite thermal resistance between the superconductingand the metallic films. These two properties of partial diversion into the shunt and of fast switching for a quick rise of the current during a default were exploited for current limitation at 77 K. FCL experiments at 50 Hz show that YBCO/Au bilayers limit the current in about 1 ms at a valueof 2.5Ic by developing electrical fields as high as 3 kV/m. Moreover, a recovery of the zero resistance state could occur under rated mode. A straightforward application of this property would be the transformer connection. Finally, results on DC current limitation and recovery under nominal mode were presented for the first time.

  12. Injection-limited current in a polymeric heterojunction

    NARCIS (Netherlands)

    Woudenbergh, T. van; Wildeman, J.; Blom, P.W.M.; Mertens, RP; Claeys, CL

    2004-01-01

    This work describes the current over an interface between two different polymeric semiconductors. The interface barrier amounts to 0.7 to 1.0 eV, which is orders of magnitude larger than the thermal energy. It is demonstrated that the current across the interface is injection limited. Furthermore, i

  13. Testing of 3-meter Prototype Fault Current Limiting Cables

    Energy Technology Data Exchange (ETDEWEB)

    Gouge, Michael J [ORNL; Duckworth, Robert C [ORNL; Demko, Jonathan A [ORNL; Rey, Christopher M [ORNL; Thompson, James R [ORNL; Lindsay, David T [ORNL; Tolbert, Jerry Carlton [ORNL; Willen, Dag [Ultera; Lentge, Heidi [Ultera; Thidemann, Carsten [Ultera; Carter, Bill [AMSC

    2009-01-01

    Two 3-m long, single-phase cables have been fabricated by Ultera from second generation (2G) superconductor supplied by American Superconductor. The first cable was made with two layers of 2G tape conductor and had a critical current of 5,750 A while the second cable had four layers and a critical current of 8,500 A. AC loss was measured for both cables at ac currents of up to 4 kArms. Ultera performed initial fault current studies of both cables in Denmark with limited currents in the range from 9.1 to 44 kA. Results from these tests will provide a basis for a 25-m long, three-phase, prototype cable to be tested at ORNL early next year and a 300-m long, fault current limiting, superconducting cable to be installed in a ConEd substation in New York City.

  14. Using electric current to surpass the microstructure breakup limit

    Science.gov (United States)

    Qin, Rongshan

    2017-01-01

    The elongated droplets and grains can break up into smaller ones. This process is driven by the interfacial free energy minimization, which gives rise to a breakup limit. We demonstrated in this work that the breakup limit can be overpassed drastically by using electric current to interfere. Electric current free energy is dependent on the microstructure configuration. The breakup causes the electric current free energy to reduce in some cases. This compensates the increment of interfacial free energy during breaking up and enables the processing to achieve finer microstructure. With engineering practical electric current parameters, our calculation revealed a significant increment of the obtainable number of particles, showing electric current a powerful microstructure refinement technology. The calculation is validated by our experiments on the breakup of Fe3C-plates in Fe matrix. Furthermore, there is a parameter range that electric current can drive spherical particles to split into smaller ones.

  15. Determining the Limiting Current Density of Vanadium Redox Flow Batteries

    Directory of Open Access Journals (Sweden)

    Jen-Yu Chen

    2014-09-01

    Full Text Available All-vanadium redox flow batteries (VRFBs are used as energy storage systems for intermittent renewable power sources. The performance of VRFBs depends on materials of key components and operating conditions, such as current density, electrolyte flow rate and electrolyte composition. Mass transfer overpotential is affected by the electrolyte flow rate and electrolyte composition, which is related to the limiting current density. In order to investigate the effect of operating conditions on mass transport overpotential, this study established a relationship between the limiting current density and operating conditions. First, electrolyte solutions with different states of charge were prepared and used for a single cell to obtain discharging polarization curves under various operating conditions. The experimental results were then analyzed and are discussed in this paper. Finally, this paper proposes a limiting current density as a function of operating conditions. The result helps predict the effect of operating condition on the cell performance in a mathematical model.

  16. Thermal performance of back-up current-limiting fuses

    Energy Technology Data Exchange (ETDEWEB)

    Torres, E.; Mazon, A.J.; Fernandez, E.; Zamora, I. [Department of Electrical Engineering, University of the Basque Country (UPV/EHU), Alameda de Urquijo, s/n, Bilbao 48013, Bizkaia (Spain); Perez, J.C. [MESA - Schneider Electric, Gatica 48110 (Spain)

    2010-12-15

    The design and development of current-limiting power fuses requires considerable time and expense on testing to verify that the maximum temperature limits under the rated current established in international standards are not exceeded. This paper presents a new methodology that reproduces the thermal behaviour of high voltage current-limiting fuses under currents up to the rated value and so, it reduces the need for testing as prototypes, more similar to the final design, can be obtained. Firstly, the methodology solves the transient heating process of the fuse to obtain the values of the power dissipated and the heat transfer coefficient, corresponding to the steady state condition. Once these values have been calculated, the temperature distribution at the surface of the complete fuse is obtained. The validity of the method proposed has been verified by comparison of the numerical values calculated with those obtained by testing real fuses. (author)

  17. Market potential of superconductor current limiters; Marktpotential von supraleitenden Strombegrenzern

    Energy Technology Data Exchange (ETDEWEB)

    Lakner, M.; Braun, D. [ABB Schweiz AG, Corporate Research, Baden-Daettwil (Switzerland); Schnyder, G.; Mauchle, P. [Schnyder Ingenieure AG, Huenenberg (Switzerland)

    2003-07-01

    This final report for the Swiss Federal Office of Energy describes the two concepts - 'resistive' and 'inductive' - used for Superconducting Fault Current Limiters (SCFCL) that utilise the transition from zero to finite resistance to limit short-circuit currents. The main advantages of SCFCL are compared to other current-limiting technologies: They can limit any type of prospective fault current, operate fail-safe, be self-triggered and self-restoring. Their main disadvantage - the cooling effort necessary - is also discussed. The application possibilities of SCFCL were investigated by simulating the impact on utility and industrial grids. Applications of SCFCL such as the coupling of medium-voltage grids and their use in series with a circuit-breaker on the secondary side of a substation transformer are discussed. It is also shown that, by using fault current limiters, considerable cost savings can be made, especially in connection with new installations or the extension of existing plants.

  18. Fault current limiter with solid-state circuit breakers

    Science.gov (United States)

    Bălan, H.; Neamț, L.; Buzdugan, M. I.; Varodi, T.; Pop, E.

    2016-08-01

    Switching of power circuit breakers is an important technical issue, especially at short circuit, since the fault current cause thermal and dynamic stresses, and the power quality worsens. Recently, the development of distributed renewable electricity induces the short circuit protection problematic because the distributed production of electric energy cause the transport networks to lose their radial character and disturbs the protective relays coordination. The modern technologies for power switching uses static fault current limiters, which offers a viable solution to remove the problems caused by large fault currents in the system. An appropriate design of the current limiting device reduces the thermal and dynamic stress and limits the fault current to a low value. The static switches are based on high power semiconductor devices that offer advantages compared to mechanical switches. Using a fault current limiter that minimizes the effect of distributed generation of electricity in a radial network on the co-ordination of protective relays is a solution to this problem in terms of switching speed and lifespan of power switches.

  19. A current limiter with superconducting coil for magnetic field shielding

    Science.gov (United States)

    Kaiho, K.; Yamaguchi, H.; Arai, K.; Umeda, M.; Yamaguchi, M.; Kataoka, T.

    2001-05-01

    The magnetic shield type superconducting fault current limiter have been built and successfully tested in ABB corporate research and so on. The device is essentially a transformer in which the secondary winding is the superconducting tube. However, due to the large AC losses and brittleness of the superconducting bulk tube, they have not yet entered market. A current limiter with superconducting coil for the magnetic field shielding is considered. By using the superconducting coil made by the multi-filamentary high Tc superconductor instead of the superconducting bulk tube, the AC losses can be reduced due to the reduced superconductor thickness and the brittleness of the bulk tube can be avoidable. This paper presents a preliminary consideration of the magnetic shield type superconducting fault current limiter with superconducting coil as secondary winding and their AC losses in comparison to that of superconducting bulk in 50 Hz operation.

  20. Limiting current of intense electron beams in a decelerating gap

    Science.gov (United States)

    Nusinovich, G. S.; Beaudoin, B. L.; Thompson, C.; Karakkad, J. A.; Antonsen, T. M.

    2016-02-01

    For numerous applications, it is desirable to develop electron beam driven efficient sources of electromagnetic radiation that are capable of producing the required power at beam voltages as low as possible. This trend is limited by space charge effects that cause the reduction of electron kinetic energy and can lead to electron reflection. So far, this effect was analyzed for intense beams propagating in uniform metallic pipes. In the present study, the limiting currents of intense electron beams are analyzed for the case of beam propagation in the tubes with gaps. A general treatment is illustrated by an example evaluating the limiting current in a high-power, tunable 1-10 MHz inductive output tube (IOT), which is currently under development for ionospheric modification. Results of the analytical theory are compared to results of numerical simulations. The results obtained allow one to estimate the interaction efficiency of IOTs.

  1. Quantum theory of space charge limited current in solids

    Energy Technology Data Exchange (ETDEWEB)

    González, Gabriel, E-mail: gabriel.gonzalez@uaslp.mx [Cátedras Conacyt, Universidad Autónoma de San Luis Potosí, San Luis Potosí 78000, Mexico and Coordinación para la Innovación y la Aplicación de la Ciencia y la Tecnología, Universidad Autónoma de San Luis Potosí, San Luis Potosí 78000 (Mexico)

    2015-02-28

    We present a quantum model of space charge limited current transport inside trap-free solids with planar geometry in the mean field approximation. We use a simple transformation which allows us to find the exact analytical solution for the steady state current case. We use our approach to find a Mott-Gurney like behavior and the mobility for single charge carriers in the quantum regime in solids.

  2. LIMITATIONS OF CURRENT APPROACHES FOR THE TREATMENT OF ACROMEGALY.

    Science.gov (United States)

    Shanik, Michael H

    2016-02-01

    Acromegaly is a rare disease characterized by hypersecretion of growth hormone (GH), typically from a benign pituitary somatotroph adenoma, that leads to subsequent hypersecretion of insulin-like growth factor 1 (IGF-1). Patients with acromegaly have an increased risk of mortality and progressive worsening of comorbidities. Surgery, medical therapy, and radiotherapy are currently available treatment approaches for patients with acromegaly, with overall therapeutic goals of lowering GH levels and achieving normal IGF-1 levels, reducing tumor size, improving comorbidities, and minimizing mortality risk. Although surgery can lead to biochemical remission in some patients with acromegaly, many patients will continue to have uncontrolled disease and require additional treatment. We reviewed recently published reports and present a summary of the safety and efficacy of current treatment modalities for patients with acromegaly. A substantial proportion of patients who receive medical therapy or radiotherapy will have persistently elevated GH and/or IGF-1. Because of the serious health consequences of continued elevation of GH and IGF-1, there is a need to improve therapeutic approaches to optimize biochemical control, particularly in high-need patient populations for whom current treatment options provide limited benefit. This review discusses current treatment options for patients with acromegaly, limitations associated with each treatment approach, and areas within the current treatment algorithm, as well as patient populations for which improved therapeutic options are needed. Novel agents in development were also highlighted, which have the potential to improve management of patients with uncontrolled or persistent acromegaly.

  3. Defining the safe current limit for opening ID photon shutter

    Energy Technology Data Exchange (ETDEWEB)

    Seletskiy, S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Photon Sciences Dept.

    2015-12-14

    The NSLS-II storage ring is protected from possible damage from insertion devices (IDs) synchrotron radiation by a dedicated active interlock system (AIS). It monitors electron beam position and angle and triggers beam drop if beam orbit exceeds the boundaries of pre-calculated active interlock envelope (AIE). The beamlines (BL) and beamline frontends (FE) are designed under assumption that the electron beam is interlocked within the AIE. For historic reasons the AIS engages the ID active interlock (AI-ID) at any non-zero beam current whenever the ID photon shutter (IDPS) is getting opened. Such arrangement creates major inconveniences for BLs commissioning. Apparently there is some IDPS safe current limit (SCL) under which the IDPS can be opened without interlocking the e-beam. The goal of this paper is to find such limit.

  4. Trapped-space-charge-limited currents in organics

    Energy Technology Data Exchange (ETDEWEB)

    Paasch, Gernot [IFW Dresden (Germany); Blom, Paul; Mandoc, Magda; Boer, Bert de [University of Groningen (Netherlands)

    2007-07-01

    The Mott-Gurney law for space charge limited current (SCLC) has been modified early to account for the presence of exponentially distributed traps. This expression has been widely used to analyse transport in organic light emitting diodes. However, the theory fails to describe the rather weak temperature dependence observed for electron transport, for instance in PPV derivatives. There we have shown that the trap-limited SCLC law is essentially modified if the density of transport states is of Gaussian type. Here, we discuss the origin of this modification and present a detailed analysis of the modified law. In addition, we derive further modifications for different combinations of densities of states of both the transport states and the trap distribution. As a result, rather different dependencies of the current on voltage, layer thickness and temperature are possible. Consequently, one has to exercise care in order to obtain reliable trap parameters from SCLC.

  5. Design Aspects and Test of an Inductive Fault Current Limiter

    Directory of Open Access Journals (Sweden)

    Arsénio Pedro

    2014-05-01

    Full Text Available Magnetic shielding inductive fault current limiters with high temperature superconducting tapes are considered as emerging devices that provide technology for the advent of modern power grids. The development of such limiters requires magnetic iron cores and leads to several design challenges regarding the constitutive parts of the limiter, namely the primary and secondary windings. Preliminary tests in a laboratory scale prototype have been carried out considering an assembly designed for simplicity in which the optimization of the magnetic coupling between the primary and secondary was not the main focus. This work addresses the design configuration of an inductive current limiter prototype regarding the assembly of the primary and secondary windings in the core. The prototype is based on a closed magnetic core wound by a primary, built from a normal electric conductor, and a short-circuited secondary, built from first generation superconducting tape. Four different design configurations are considered. Through experimental tests, the performance of such prototype is discussed and compared, in terms of normal and fault operation regimes. The results show that all the configurations assure effective magnetic shielding at normal operation regime, however, at fault operation regime, there are differences among configurations.

  6. Superconducting fault current-limiter with variable shunt impedance

    Science.gov (United States)

    Llambes, Juan Carlos H; Xiong, Xuming

    2013-11-19

    A superconducting fault current-limiter is provided, including a superconducting element configured to resistively or inductively limit a fault current, and one or more variable-impedance shunts electrically coupled in parallel with the superconducting element. The variable-impedance shunt(s) is configured to present a first impedance during a superconducting state of the superconducting element and a second impedance during a normal resistive state of the superconducting element. The superconducting element transitions from the superconducting state to the normal resistive state responsive to the fault current, and responsive thereto, the variable-impedance shunt(s) transitions from the first to the second impedance. The second impedance of the variable-impedance shunt(s) is a lower impedance than the first impedance, which facilitates current flow through the variable-impedance shunt(s) during a recovery transition of the superconducting element from the normal resistive state to the superconducting state, and thus, facilitates recovery of the superconducting element under load.

  7. Imaging fast calcium currents beyond the limitations of electrode techniques.

    Science.gov (United States)

    Jaafari, Nadia; De Waard, Michel; Canepari, Marco

    2014-09-16

    The current understanding of Ca(2+) channel function is derived from the use of the patch-clamp technique. In particular, the measurement of fast cellular Ca(2+) currents is routinely achieved using whole-cell voltage-clamp recordings. However, this experimental approach is not applicable to the study of local native Ca(2+) channels during physiological changes of membrane potential in complex cells, since the voltage-clamp configuration constrains the membrane potential to a given value. Here, we report for the first time to our knowledge that Ca(2+) currents from individual cells can be quantitatively measured beyond the limitations of the voltage-clamp approach using fast Ca(2+) imaging with low-affinity indicators. The optical measurement of the Ca(2+) current was correlated with the membrane potential, simultaneously measured with a voltage-sensitive dye to investigate the activation of Ca(2+) channels along the apical dendrite of the CA1 hippocampal pyramidal neuron during the back-propagation of an action potential. To validate the method, we analyzed the voltage dependence of high- and low-voltage-gated Ca(2+) channels. In particular, we measured the Ca(2+) current component mediated by T-type channels, and we investigated the mechanisms of recovery from inactivation of these channels. This method is expected to become a reference approach to investigate Ca(2+) channels in their native physiological environment.

  8. Current Status and Research into Overcoming Limitations of Capsule Endoscopy.

    Science.gov (United States)

    Kwack, Won Gun; Lim, Yun Jeong

    2016-01-01

    Endoscopic investigation has a critical role in the diagnosis and treatment of gastrointestinal (GI) diseases. Since 2001, capsule endoscopy (CE) has been available for small-bowel exploration and is under continuous development. During the past decade, CE has achieved impressive improvements in areas such as miniaturization, resolution, and battery life. As a result, CE is currently a first-line tool for the investigation of the small bowel in obscure gastrointestinal bleeding and is a useful alternative to wired enteroscopy. Nevertheless, CE still has several limitations, such as incomplete examination and limited diagnostic and therapeutic capabilities. To resolve these problems, many groups have suggested several models (e.g., controlled CO2 insufflation system, magnetic navigation system, mobile robotic platform, tagging and biopsy equipment, and targeted drug-delivery system), which are in development. In the near future, new technological advances will improve the capabilities of CE and broaden its spectrum of applications not only for the small bowel but also for the colon, stomach, and esophagus. The purpose of this review is to introduce the current status of CE and to review the ongoing development of solutions to address its limitations.

  9. Correcting Acidosis during Hemodialysis: Current Limitations and a Potential Solution.

    Science.gov (United States)

    Tovbin, David; Sherman, Richard A

    2016-01-01

    The deleterious catabolic and pro-inflammatory effects of acidosis in hemodialysis (HD) patients and the importance of its correction for limiting mineral bone disease (MBD) are well known. Although oral base therapy could be a solution for correcting acidosis in HD patients, it increases their already enormous medication load and sodium intake; this approach is not used commonly. Therefore, we need to rely more on correcting acidosis during the HD procedure, which is difficult to achieve, in part, because HD is an intermittent therapy. The currently used fixed dialysate bicarbonate concentrations are associated with pre-HD acidosis and intra-dialytic alkalosis. We suggest that a decreasing dialysate bicarbonate concentration from an initially high concentration be considered as a means of correcting acidosis with limited intra-dialytic alkalosis. Some evidence, as well as theoretical considerations, supports such an approach. © 2015 Wiley Periodicals, Inc.

  10. Pediatric minimally invasive surgery in Africa: limitations and current situation.

    Science.gov (United States)

    Loveland, Jerome; Numanoglu, Alp; Hay, Sameh Abdel

    2012-05-01

    The second largest and most populous continent, with an exploding pediatric population, Africa has an overwhelming burden on its very limited pediatric surgical services. In an international environment of progressively advancing endoscopic and robotic surgical techniques, the authors focus on the current role of endoscopic surgery on the continent and explore the potential reasons for its delayed acceptance and implementation. They proceed to document the spectrum of what is available and, using their "African experience," expand on financially viable models of further rolling out these techniques, including discussion around suitable training models for surgeons and their teams. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Proposed hybrid superconducting fault current limiter for distribution systems

    Energy Technology Data Exchange (ETDEWEB)

    Elmitwally, A. [Elect. Eng. Dept., Mansoura University, Mansoura 35516 (Egypt)

    2009-11-15

    In this paper, a new hybrid fault current limiter is proposed for primary distribution systems. It incorporates a high temperature superconducting element in parallel with other two branches. The first is an inductive impedance to share the fault current with. The second branch is a gate-turn-off thyristor switch controlled to work in either of two modes. For the main mode, it controls the temperature of the superconducting element and protect it against damaging excessive heating. Instead, it keeps the device applicable without that superconducting element in the auxiliary operation mode. The design, control and operation of the device is addressed. Its performance in 11 kV distribution systems with DG is investigated. The factors affecting the device behavior for different scenarios are explored. (author)

  12. Potential and limitations of eddy current lockin-thermography

    Science.gov (United States)

    Riegert, G.; Gleiter, A.; Busse, G.

    2006-04-01

    Eddy current thermography uses an induction coil to induce eddy currents in conductive materials. The involved resistive losses heat the sample. By modulation of the eddy current amplitude, thermal waves are generated which interact with boundaries thereby revealing defects. Conventional eddy current testing has only a limited depth range due to the skin effect of metal samples. In Induction-Lockin-Thermography (ILT) the depth range is extended by the thermal penetration depth. An infrared camera monitors the modulation of the temperature field on the surface as a response to the coded excitation thereby allowing for fast imaging of defects in larger areas without the need of slow point-by-point mapping. This response is decoded by a Fourier analysis at the modulation frequency. So the extracted information is displayed by just two images where one displays local amplitude and the other local phase. ILT has significant advantages as compared to inductive heating with visual inspection of the thermographic sequence: Phase angle images are independent of most artifacts like reflections, variation in emission coefficient, or inhomogeneous heating. Due to the performed Fourier analysis of the temperature image sequence, the signal-to-noise ratio in the amplitude and phase images is significantly better than in single temperature images of the sequence. Induction heating is confined to conductive materials. However, it is applicable not only to metals but also to carbon fiber reinforced laminates (CFRP) or carbon fiber reinforced ceramics (C/C-SiC). The presented examples for applications of ILT illustrate the potential and limitations of this new non-destructive inspection method.

  13. Thermal instability and current-voltage scaling in superconducting fault current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Zeimetz, B [Department of Materials Science and Metallurgy, Cambridge University, Pembroke Street, Cambridge CB1 3QZ (United Kingdom); Tadinada, K [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Eves, D E [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Coombs, T A [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Evetts, J E [Department of Materials Science and Metallurgy, Cambridge University, Pembroke Street, Cambridge CB1 3QZ (United Kingdom); Campbell, A M [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom)

    2004-04-01

    We have developed a computer model for the simulation of resistive superconducting fault current limiters in three dimensions. The program calculates the electromagnetic and thermal response of a superconductor to a time-dependent overload voltage, with different possible cooling conditions for the surfaces, and locally variable superconducting and thermal properties. We find that the cryogen boil-off parameters critically influence the stability of a limiter. The recovery time after a fault increases strongly with thickness. Above a critical thickness, the temperature is unstable even for a small applied AC voltage. The maximum voltage and maximum current during a short fault are correlated by a simple exponential law.

  14. Ion current rectification, limiting and overlimiting conductances in nanopores.

    Directory of Open Access Journals (Sweden)

    Liesbeth van Oeffelen

    Full Text Available Previous reports on Poisson-Nernst-Planck (PNP simulations of solid-state nanopores have focused on steady state behaviour under simplified boundary conditions. These are Neumann boundary conditions for the voltage at the pore walls, and in some cases also Donnan equilibrium boundary conditions for concentrations and voltages at both entrances of the nanopore. In this paper, we report time-dependent and steady state PNP simulations under less restrictive boundary conditions, including Neumann boundary conditions applied throughout the membrane relatively far away from the nanopore. We simulated ion currents through cylindrical and conical nanopores with several surface charge configurations, studying the spatial and temporal dependence of the currents contributed by each ion species. This revealed that, due to slow co-diffusion of oppositely charged ions, steady state is generally not reached in simulations or in practice. Furthermore, it is shown that ion concentration polarization is responsible for the observed limiting conductances and ion current rectification in nanopores with asymmetric surface charges or shapes. Hence, after more than a decade of collective research attempting to understand the nature of ion current rectification in solid-state nanopores, a relatively intuitive model is retrieved. Moreover, we measured and simulated current-voltage characteristics of rectifying silicon nitride nanopores presenting overlimiting conductances. The similarity between measurement and simulation shows that overlimiting conductances can result from the increased conductance of the electric double-layer at the membrane surface at the depletion side due to voltage-induced polarization charges. The MATLAB source code of the simulation software is available via the website http://micr.vub.ac.be.

  15. Ion current rectification, limiting and overlimiting conductances in nanopores.

    Science.gov (United States)

    van Oeffelen, Liesbeth; Van Roy, Willem; Idrissi, Hosni; Charlier, Daniel; Lagae, Liesbet; Borghs, Gustaaf

    2015-01-01

    Previous reports on Poisson-Nernst-Planck (PNP) simulations of solid-state nanopores have focused on steady state behaviour under simplified boundary conditions. These are Neumann boundary conditions for the voltage at the pore walls, and in some cases also Donnan equilibrium boundary conditions for concentrations and voltages at both entrances of the nanopore. In this paper, we report time-dependent and steady state PNP simulations under less restrictive boundary conditions, including Neumann boundary conditions applied throughout the membrane relatively far away from the nanopore. We simulated ion currents through cylindrical and conical nanopores with several surface charge configurations, studying the spatial and temporal dependence of the currents contributed by each ion species. This revealed that, due to slow co-diffusion of oppositely charged ions, steady state is generally not reached in simulations or in practice. Furthermore, it is shown that ion concentration polarization is responsible for the observed limiting conductances and ion current rectification in nanopores with asymmetric surface charges or shapes. Hence, after more than a decade of collective research attempting to understand the nature of ion current rectification in solid-state nanopores, a relatively intuitive model is retrieved. Moreover, we measured and simulated current-voltage characteristics of rectifying silicon nitride nanopores presenting overlimiting conductances. The similarity between measurement and simulation shows that overlimiting conductances can result from the increased conductance of the electric double-layer at the membrane surface at the depletion side due to voltage-induced polarization charges. The MATLAB source code of the simulation software is available via the website http://micr.vub.ac.be.

  16. Noise limits of CMOS current interfaces for biosensors: a review.

    Science.gov (United States)

    Crescentini, Marco; Bennati, Marco; Carminati, Marco; Tartagni, Marco

    2014-04-01

    Current sensing readout is one of the most frequent techniques used in biosensing due to the charge-transfer phenomena occurring at solid-liquid interfaces. The development of novel nanodevices for biosensing determines new challenges for electronic interface design based on current sensing, especially when compact and efficient arrays need to be organized, such as in recent trends of rapid label-free electronic detection of DNA synthesis. This paper will review the basic noise limitations of current sensing interfaces with particular emphasis on integrated CMOS technology. Starting from the basic theory, the paper presents, investigates and compares charge-sensitive amplifier architectures used in both continuous-time and discrete-time approaches, along with their design trade-offs involving noise floor, sensitivity to stray capacitance and bandwidth. The ultimate goal of this review is providing analog designers with helpful design rules and analytical tools. Also, in order to present a comprehensive overview of the state-of-the-art, the most relevant papers recently appeared in the literature about this topic are discussed and compared.

  17. CURRENT-VOLTAGE CURVES FOR TREATING EFFLUENT CONTAINING HEDP: DETERMINATION OF THE LIMITING CURRENT

    Directory of Open Access Journals (Sweden)

    T. Scarazzato

    2015-12-01

    Full Text Available Abstract Membrane separation techniques have been explored for treating industrial effluents to allow water reuse and component recovery. In an electrodialysis system, concentration polarization causes undesirable alterations in the ionic transportation mechanism. The graphic construction of the current voltage curve is proposed for establishing the value of the limiting current density applied to the cell. The aim of this work was to determine the limiting current density in an electrodialysis bench stack, the function of which was the treatment of an electroplating effluent containing HEDP. For this, a system with five compartments was used with a working solution simulating the rinse waters of HEDP-based baths. The results demonstrated correlation between the regions defined by theory and the experimental data.

  18. Fault current limitation with HTc superconductors; Limitation de courant a partir de materiaux supraconducteurs HTc

    Energy Technology Data Exchange (ETDEWEB)

    Buzon, D.

    2002-09-15

    This report deals with the possibility of using high critical temperature (HTc) superconductors for current limitation. The transition from a superconductive to a high dissipative state could be used to limit inrush currents. This application of superconductivity is very attractive because it's an innovative device for electrical networks without any conventional equivalence at high voltage. This device would allow to improve the density of connections and the continuity of the electrical distribution. This study can be divided into two fields. The aim of the first one is to analyse the behaviour of different HTc superconductors for current limitation. We carried out experimental measurements to characterise those conductors during a nominal AC rating (measurements of losses) and during a fault setting. Particularly, a description of the transition in bulk textured YBCO samples near Tc was made of inhomogeneous transition of the device and to estimate its losses. Finally, a 1 kV / 100 A demonstrator made of 43 meanders of textured YBCO was tested at 90,5 K. Thermal gradients seem to be responsible of the altering of some of the samples. The other part of this study concerns the dynamic of the transition. Near Tc, our experiments showed that the transition is more homogeneous. Experimental measurements also showed the influence of thermal exchanges with the cryogenic surrounding on the transition. This point can be justified if the dissipated energy is locally concentrated. (author)

  19. LIFELONG LEARNING THROUGH SECOND LIFE: CURRENT TRENDS, POTENTIALS AND LIMITATIONS

    Directory of Open Access Journals (Sweden)

    Nil GOKSEL-CANBEK

    2011-08-01

    Full Text Available Lifelong Learning (LLL has been a remarkable response to people-centered educational demand of 21st century. In order to provide effective formal, non-formal, and informal learning, immersive educational activities undertaken throughout life should be aimed to create a learning society in which people can experience individual and collective learning with no constrains of time or location. The concept of lifelong learning within the context of distance immersive education encompasses diverse 3D activities. The three dimensional, Web-based structured activities supported by distance learning technologies can be viewed as interactive tools which foster LLL. In this perspective, Second Life (SL can be regarded as one of the learning simulation milieus that allow learners to participate in various educational LLL activities in individual or group forms. The following paper examines how SL, taking advantage of its simulative nature and the possibility for creative interaction among participants, which are also common in games, allows the learners to participate in immersive constructivist learning activities. The article will also touch on the current uses of SL as a tool for LLL, as well as its potentials for further development according to the current trends in adult education. Further, the authors will discuss its limitations and will make suggestions towards a more complete pedagogical use.

  20. Evolution and current development of Transversal Themes: possibilities and limits

    Directory of Open Access Journals (Sweden)

    Carlos Rosales López

    2015-02-01

    Full Text Available The aim of this study was to determine the characteristics of the evolution and current development of transversal themes in education, considering them basically as important social cuestions with great influence in the overall education of the student. Specifically it seeks to clarify the level of preparation and dedication of teachers and schools to teach them. To do this, legislation used in our country (organics laws and decrees curriculum were analyzed and also the contribution of outstanding educators, institutions and researchers. We analyzed the characteristics of transversal themes in the educational project and the teaching program, its development in the clasroom and its projection out of it through the help of family and community. Conclusions about their current status (possibilities and limitations are derived and future proposals are made on the improvement of initial and ongoing training of teachers, to increase their collegiate or cooperative work of planning, intervention and evaluation, increased media and counseling in use, the need for increased communication and collaboration with families and other community institutions.How to reference this articleRosales López, C. (2015. Evolución y desarrollo actual de los Temas Transversales: posibilidades y límites. Foro de Educación, 13(18, pp. 143-160. doi: http://dx.doi.org/10.14516/fde.2015.013.018.008

  1. Superconducting matrix fault current limiter with current-driven trigger mechanism

    Science.gov (United States)

    Yuan, Xing

    2008-04-15

    A modular and scalable Matrix-type Fault Current Limiter (MFCL) that functions as a "variable impedance" device in an electric power network, using components made of superconducting and non-superconducting electrically conductive materials. An inductor is connected in series with the trigger superconductor in the trigger matrix and physically surrounds the superconductor. The current surge during a fault will generate a trigger magnetic field in the series inductor to cause fast and uniform quenching of the trigger superconductor to significantly reduce burnout risk due to superconductor material non-uniformity.

  2. Circulating thyroid cancer biomarkers: Current limitations and future prospects.

    Science.gov (United States)

    Nixon, Alexander M; Provatopoulou, Xeni; Kalogera, Eleni; Zografos, George N; Gounaris, Antonia

    2017-08-01

    Differentiated thyroid cancer (DTC) is the most common malignancy of the endocrine system. There has been a significant increase in its incidence over the past two decades attributable mainly to the use of more sensitive diagnostic modalities. Ultrasound-guided fine needle aspiration cytology is the mainstay of diagnosis of benign disorders and malignancy. However, approximately 20% of lesions cannot be adequately categorized as benign or malignant. In the postoperative setting, monitoring of thyroglobulin (Tg) levels has been employed for the detection of disease recurrence. Unfortunately, Tg antibodies are common and interfere with Tg measurement in this subset of patients. Despite this limitation, Tg remains the sole widely used thyroid cancer biomarker in the clinical setting. In an attempt to bypass antibody interference, research has focused mainly on mRNA targets thought to be exclusively expressed in thyroid cells. Tg and thyroid stimulating hormone receptor (TSHR) mRNA have been extensively studied both for discerning between benign disease and malignancy and in postoperative disease surveillance. However, results among reports have been inconsistent probably reflecting considerable differences in methodology. Recently, microRNA (miRNA) targets are being investigated as potential biomarkers in DTC. MiRNAs are more stable molecules and theoretically are not as vulnerable as mRNA during manipulation. Initial results have been encouraging but large-scale studies are warranted to verify and elucidate their potential application in diagnosis and postoperative surveillance of thyroid cancer. Several other novel targets, primarily mutations and circulating cells, are currently emerging as promising thyroid cancer circulating biomarkers. Although interesting and intriguing, data are limited and derive from small-scale studies in specific patient cohorts. Further research findings demonstrating their value are awaited with anticipation. © 2017 John Wiley & Sons

  3. Current parallel I/O limitations to scalable data analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Mascarenhas, Ajith Arthur; Pebay, Philippe Pierre

    2011-07-01

    This report describes the limitations to parallel scalability which we have encountered when applying our otherwise optimally scalable parallel statistical analysis tool kit to large data sets distributed across the parallel file system of the current premier DOE computational facility. This report describes our study to evaluate the effect of parallel I/O on the overall scalability of a parallel data analysis pipeline using our scalable parallel statistics tool kit [PTBM11]. In this goal, we tested it using the Jaguar-pf DOE/ORNL peta-scale platform on a large combustion simulation data under a variety of process counts and domain decompositions scenarios. In this report we have recalled the foundations of the parallel statistical analysis tool kit which we have designed and implemented, with the specific double intent of reproducing typical data analysis workflows, and achieving optimal design for scalable parallel implementations. We have briefly reviewed those earlier results and publications which allow us to conclude that we have achieved both goals. However, in this report we have further established that, when used in conjuction with a state-of-the-art parallel I/O system, as can be found on the premier DOE peta-scale platform, the scaling properties of the overall analysis pipeline comprising parallel data access routines degrade rapidly. This finding is problematic and must be addressed if peta-scale data analysis is to be made scalable, or even possible. In order to attempt to address these parallel I/O limitations, we will investigate the use the Adaptable IO System (ADIOS) [LZL+10] to improve I/O performance, while maintaining flexibility for a variety of IO options, such MPI IO, POSIX IO. This system is developed at ORNL and other collaborating institutions, and is being tested extensively on Jaguar-pf. Simulation code being developed on these systems will also use ADIOS to output the data thereby making it easier for other systems, such as ours, to

  4. Fabrication of HTS dc Bias Coil for 35 kV/90 MVA SFCL

    Institute of Scientific and Technical Information of China (English)

    Jing-Yin Zhang; Wei-Zhi Gong; Zheng-Jian Cao; Hui Hong; Bo Tian; Yang Wang; Jian-Zhong Wang; Xiao-Ye Niu; Ying Xin

    2008-01-01

    For a saturated iron core fault current limiter, superconductor is the only suitable material to make the dc bias coil, especially when the device is used in a high voltage power grid. Commonly, supercon- ducting wires are used to wind the dc bias coil. Since the performance of the wires changes greatly under magnetic fields, the calculation of the field spatial distraction is essential to the optimization of the superconducting magnet. A superconducting coil with 141000 ampere-turns magnetizing capacity made of 17600 meters of BSCCO 2223 HTS tapes was fabricated. This coil was built for a 35 kV/90 MVA saturated iron-core fault current limiter. Computer simulations on magnetic field distribution were carried out to optimize the structural design, and experiments were done to verify the performance of the coil. The configuration and the key parameters of the coil will be reported in this paper.

  5. Current limitations and challenges in nanowaste detection, characterisation and monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Part, Florian; Zecha, Gudrun [Department of Water-Atmosphere-Environment, University of Natural Resources and Life Sciences, Institute of Waste Management, Muthgasse 107, 1190 Vienna (Austria); Causon, Tim [Department of Chemistry, Division of Analytical Chemistry, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna (Austria); Sinner, Eva-Kathrin [Department of Nanobiotechnology, Institute for Synthetic Bioarchitectures, University of Natural Resources and Life Sciences, Muthgasse 11/II, 1190 Vienna (Austria); Huber-Humer, Marion, E-mail: marion.huber-humer@boku.ac.at [Department of Water-Atmosphere-Environment, University of Natural Resources and Life Sciences, Institute of Waste Management, Muthgasse 107, 1190 Vienna (Austria)

    2015-09-15

    Highlights: • First review on detection of nanomaterials in complex waste samples. • Focus on nanoparticles in solid, liquid and gaseous waste samples. • Summary of current applicable methods for nanowaste detection and characterisation. • Limitations and challenges of characterisation of nanoparticles in waste. - Abstract: Engineered nanomaterials (ENMs) are already extensively used in diverse consumer products. Along the life cycle of a nano-enabled product, ENMs can be released and subsequently accumulate in the environment. Material flow models also indicate that a variety of ENMs may accumulate in waste streams. Therefore, a new type of waste, so-called nanowaste, is generated when end-of-life ENMs and nano-enabled products are disposed of. In terms of the precautionary principle, environmental monitoring of end-of-life ENMs is crucial to allow assessment of the potential impact of nanowaste on our ecosystem. Trace analysis and quantification of nanoparticulate species is very challenging because of the variety of ENM types that are used in products and low concentrations of nanowaste expected in complex environmental media. In the framework of this paper, challenges in nanowaste characterisation and appropriate analytical techniques which can be applied to nanowaste analysis are summarised. Recent case studies focussing on the characterisation of ENMs in waste streams are discussed. Most studies aim to investigate the fate of nanowaste during incineration, particularly considering aerosol measurements; whereas, detailed studies focusing on the potential release of nanowaste during waste recycling processes are currently not available. In terms of suitable analytical methods, separation techniques coupled to spectrometry-based methods are promising tools to detect nanowaste and determine particle size distribution in liquid waste samples. Standardised leaching protocols can be applied to generate soluble fractions stemming from solid wastes, while

  6. Limit currents and value distribution of holomorphic maps

    CERN Document Server

    Buurns, Daniel

    2010-01-01

    We construct $d$-closed and $dd^c$-closed positive currents associated to a holomorphic map $\\phi$ via cluster points of normalized weighted truncated image currents. They are constructed using analogues of the Ahlfors length-area inequality in higher dimensions. Such classes of currents are loosely referred to as Ahlfors currents. We give some applications to equidistribution problems in value distribution theory.

  7. On Dynamic Range Limitations of CMOS Current Conveyors

    DEFF Research Database (Denmark)

    Bruun, Erik

    1999-01-01

    This paper is concerned with the dynamic range of continuous time CMOS current mode circuits. As a representative current mode device a class AB current conveyor is examined. First, the voltage input range of the high impedance Y input is investigated. Next, the current input range of the low...... frequency band and for the situation where the conveyor is used over the full bandwidth achievable. Finally, the optimisation of the current input range is related to the distortion characteristics and it is pointed out that to a first order approximation the distortion is independent of the current range....... impedance X input is investigated. It is compared to the thermal noise in the X to Z signal path in order to evaluate the dynamic range, and the dependencies of the dynamic range on the supply voltage and the transistor lay-out is derived, both for the situation where the conveyor is used over a narrow...

  8. Novel Topology of Saturated-core Fault Current Limiter

    NARCIS (Netherlands)

    Cvoric, D.

    2010-01-01

    Increasing levels of fault currents in utility grids are expected to result in mechanical and thermal overstresses of different power system components. To cope with these increased levels, expensive upgrades and replacements of currently employed Circuit Breakers might be required in the near futur

  9. Limitations of eddy current testing in a fast reactor environment

    Science.gov (United States)

    Wu, Tao; Bowler, John R.

    2016-02-01

    The feasibility of using eddy current probes for detecting flaws in fast nuclear reactor structures has been investigated with the aim of detecting defects immersed in electrically conductive coolant including under liquid sodium during standby. For the inspections to be viable, there is a need to use an encapsulated sensor system that can be move into position with the aid of visualization tools. The initial objective being to locate the surface to be investigated using, for example, a combination of electromagnetic sensors and sonar. Here we focus on one feature of the task in which eddy current probe impedance variations due to interaction with the external surface of a tube are evaluated in order to monitor the probe location and orientation during inspection.

  10. Current status of nuclear medicine in chronic airflow limitation

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, S.W.; Agnew, J.E.

    1987-06-01

    Radionuclide imaging, quite apart from its role in the diagnosis of pulmonary embolism, offers information about the distribution of ventilatory and perfusion abnormalities within the lung. The extent of ventilatory abnormality seen can be related to the severity of airways obstruction as assessed spirometrically, whilst abnormalities in the matching of perfusion to ventilation can be related to the severity of hypoxaemia in patients with chronic airflow limitation. Clearance of mucus from the lungs of patients with chronic mucus hypersection may be assessed by following the clearance rate of insoluble radioaerosol particles; by such means the relative contributions of mucociliary transport and of cough to the overall clearance can be observed. Clearance is often severely impaired in patients with airways obstruction; the radioaerosol technique can be used to determine the effects of drug or physiotherapy treatment. Chronic airflow limitation leading to hypoxaemia can be associated with pulmonary artery hypertension and right ventricular hypertrophy - this may be investigated noninvasively by a radionuclide test of right ventricular ejection fraction.

  11. PRA: A PERSPECTIVE ON STRENGTHS, CURRENT LIMITATIONS, AND POSSIBLE IMPROVEMENTS

    Directory of Open Access Journals (Sweden)

    ALI MOSLEH

    2014-02-01

    Full Text Available Probabilistic risk assessment (PRA has been used in various technological fields to assist regulatory agencies, managerial decision makers, and systems designers in assessing and mitigating the risks inherent in these complex arrangements. Has PRA delivered on its promise? How do we gage PRA performance? Are our expectations about value of PRA realistic? Are there disparities between what we get and what we think we are getting form PRA and its various derivatives? Do current PRAs reflect the knowledge gained from actual events? How do we address potential gaps? These are some of the questions that have been raised over the years since the inception of the field more than forty years ago. This paper offers a brief assessment of PRA as a technical discipline in theory and practice, its key strengths and weaknesses, and suggestions on ways to address real and perceived shortcomings.

  12. Fighting Sharka in Peach: Current Limitations and Future Perspectives

    Science.gov (United States)

    Cirilli, Marco; Geuna, Filippo; Babini, Anna R.; Bozhkova, Valentina; Catalano, Luigi; Cavagna, Beniamino; Dallot, Sylvie; Decroocq, Véronique; Dondini, Luca; Foschi, Stefano; Ilardi, Vincenza; Liverani, Alessandro; Mezzetti, Bruno; Minafra, Angelantonio; Pancaldi, Marco; Pandolfini, Tiziana; Pascal, Thierry; Savino, Vito N.; Scorza, Ralph; Verde, Ignazio; Bassi, Daniele

    2016-01-01

    Sharka, caused by Plum Pox Virus (PPV), is by far the most important infectious disease of peach [P. persica (L.) Batsch] and other Prunus species. The progressive spread of the virus in many important growing areas throughout Europe poses serious issues to the economic sustainability of stone fruit crops, peach in particular. The adoption of internationally agreed-upon rules for diagnostic tests, strain-specific monitoring schemes and spatial–temporal modeling of virus spread, are all essential for a more effective sharka containment. The EU regulations on nursery activity should be modified based on the zone delimitation of PPV presence, limiting open-field production of propagation materials only to virus-free areas. Increasing the efficiency of preventive measures should be augmented by the short-term development of resistant cultivars. Putative sources of resistance/tolerance have been recently identified in peach germplasm, although the majority of novel resistant sources to PPV-M have been found in almond. However, the complexity of introgression from related-species imposes the search for alternative strategies. The use of genetic engineering, particularly RNA interference (RNAi)-based approaches, appears as one of the most promising perspectives to introduce a durable resistance to PPV in peach germplasm, notwithstanding the well-known difficulties of in vitro plant regeneration in this species. In this regard, rootstock transformation to induce RNAi-mediated systemic resistance would avoid the transformation of numerous commercial cultivars, and may alleviate consumer resistance to the use of GM plants. PMID:27625664

  13. Fighting Sharka in Peach: Current Limitations and Future Perspectives

    Directory of Open Access Journals (Sweden)

    Marco Cirilli

    2016-08-01

    Full Text Available Sharka, caused by Plum Pox Virus (PPV, is by far the most important infectious disease of peach [P. persica (L. Batsch] and other Prunus species. The progressive spread of the virus in many important growing areas throughout Europe poses serious issues to the economic sustainability of stone fruit crops, peach in particular. The adoption of internationally agreed-upon rules for diagnostic tests, strain-specific monitoring schemes and spatial-temporal modeling of virus spread, are all essential for a more effective sharka containment. The EU regulations on nursery activity should be modified based on the zone delimitation of PPV presence, limiting open-field production of propagation materials only to virus-free areas. Increasing the efficiency of preventive measures should be augmented by the short-term development of resistant cultivars. Putative sources of resistance/tolerance have been recently identified in peach germplasm, although the majority of novel resistant sources to PPV-M have been found in almond. However, the complexity of introgression from related-species imposes the search for alternative strategies. The use of genetic engineering, particularly RNAi-based approaches, appears as one of the most promising perspectives to introduce a durable resistance to PPV in peach germplasm, notwithstanding the well-known difficulties of in vitro plant regeneration in this species. In this regard, rootstock transformation to induce RNAi-mediated systemic resistance to PPV would avoid the transformation of numerous commercial cultivars, and may alleviate consumer resistance to the use of GM plants.

  14. Melt textured YBaCuO transport current capability. Application to current limitation; Capacite de transport et de limitation du courant des materiaux YBaCuO textures

    Energy Technology Data Exchange (ETDEWEB)

    Porcar, L.; Belmont, O.; Noudem, J.G.; Barbut, J.M.; Barrault, M. [Schneider Electric S.A., Grenoble (France); Bourgault, D.; Chaud, X.; Tournier, R. [CNRS-EPM/Matformag, Grenoble (France); Tixador, P. [CNRS-CRTBT/LEG, Grenoble (France)

    1998-01-01

    Pulsed and permanent sinusoidal transport current have been applied to melt textured Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} in order to estimate its current limitation capability. High pulsed transport currents reaching 9000A (23000 A/cm{sup 2}) crossed a 4 cm long sample. In permanent sinusoidal current, 3000 A (7800 A/cm{sup 2}) crossed the sample without showing any resistive losses. Above the critical current, the transition from the superconducting to the normal state is strongly abrupt. (orig.). 8 refs.

  15. Evaluation of Ferrite Chip Beads as Surge Current Limiters in Circuits with Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander

    2014-01-01

    Limiting resistors are currently required to be connected in series with tantalum capacitors to reduce the risk of surge current failures. However, application of limiting resistors decreases substantially the efficiency of the power supply systems. An ideal surge current limiting device should have a negligible resistance for DC currents and high resistance at frequencies corresponding to transients in tantalum capacitors. This work evaluates the possibility of using chip ferrite beads (FB) as such devices. Twelve types of small size FBs from three manufacturers were used to evaluate their robustness under soldering stresses and at high surge current spikes associated with transients in tantalum capacitors. Results show that FBs are capable to withstand current pulses that are substantially greater than the specified current limits. However, due to a sharp decrease of impedance with current, FBs do not reduce surge currents to the required level that can be achieved with regular resistors.

  16. A Solid-State Fault Current Limiting Device for VSC-HVDC Systems

    Science.gov (United States)

    Larruskain, D. Marene; Zamora, Inmaculada; Abarrategui, , Oihane; Iturregi, Araitz

    2013-08-01

    Faults in the DC circuit constitute one of the main limitations of voltage source converter VSC-HVDC systems, as the high fault currents can damage seriously the converters. In this article, a new design for a fault current limiter (FCL) is proposed, which is capable of limiting the fault current as well as interrupting it, isolating the DC grid. The operation of the proposed FCL is analysed and verified with the most usual faults that can occur in overhead lines.

  17. Remote forcing of subsurface currents and temperatures near the northern limit of the California Current System

    Science.gov (United States)

    Engida, Zelalem; Monahan, Adam; Ianson, Debby; Thomson, Richard E.

    2016-10-01

    Local and remote wind forcing of upwelling along continental shelves of coastal upwelling regions play key roles in driving biogeochemical fluxes, including vertical net fluxes of carbon and nutrients. These fluxes are responsible for high primary productivity, which in turn supports a lucrative fishery in these regions. However, the relative contributions of local versus remote wind forcing are not well quantified or understood. We present results of coherence analyses between currents at a single mooring site (48.5°N, 126°W) in the northern portion of the California Current System (CalCS) from 1989 to 2008 and coincident time series of North America Regional Reanalysis (NARR) 10 m wind stress within the CalCS (36-54°N, 120-132°W). The two-decade-long current records from the three shallowest depths (35, 100, and 175 m) show a remote response to winds from south as far as 36°N. In contrast, only temperatures at the deepest depth (400 m) show strong coherences with remote winds. Weaker local wind influence is observed in both the currents and 400 m temperatures but is mostly due to the large spatial coherence within the wind field itself. Lack of coherence between distal winds and the 400 m currents suggests that the temperature variations at that depth are driven by vertical motion resulting from poleward travelling coastal trapped waves (CTWs). Understanding the effects of remote forcing in coastal upwelling regions is necessary for determining the occurrence and timing of extreme conditions in coastal oceans, and their subsequent impact on marine ecosystems.

  18. Series transformer based diode-bridge-type solid state fault current limiter

    Institute of Scientific and Technical Information of China (English)

    Amir HEIDARY; Hamid RADMANESH; Seyed Hamid FATHI; G B GHAREHPETIAN

    2015-01-01

    We propose a novel series transformer based diode-bridge-type solid state fault current limiter (SSFCL). To control the fault current, a series RLC branch is connected to the secondary side of an isolation series transformer. Based on this RLC branch, two current limiting modes are created. In the first mode, R and C are bypassed via a paralleled power electronic switch (insulated-gate bipolar transistor, IGBT) and L remains connected to the secondary side of the transformer as a DC reactor. In the second mode, the series reactor impedance is not enough to limit the fault current. In this case, the fault current can be con-trolled by selecting a proper on-off duration of the parallel IGBT, across the series damping resistor (R) and capacitor, which inserts high impedance into the line to limit the fault current. Then, by controlling the magnitude of the DC reactor current, the fault current is reduced and the voltage of the point of common coupling (PCC) is kept at an acceptable level. In addition, in the new SSFCL, the series RC branch, connected in parallel with the IGBT, serves as a snubber circuit for decreasing the transient recovery voltage (TRV) of the IGBT during on-off states. Therefore, the power quality indices can be improved. The measure-ment results of a built prototype are presented to support the simulation and theoretical studies. The proposed SSFCL can limit the fault current without any delay and successfully smooth the fault current waveform.

  19. A double-stage start-up structure to limit the inrush current used in current mode charge pump

    Science.gov (United States)

    Cong, Liu; Xinquan, Lai; Hanxiao, Du; Yuan, Chi

    2016-06-01

    A double-stage start-up structure to limit the inrush current used in current-mode charge pump with wide input range, fixed output and multimode operation is presented in this paper. As a widely utilized power source implement, a Li-battery is always used as the power supply for chips. Due to the internal resistance, a potential drop will be generated at the input terminal of the chip with an input current. A false shut down with a low supply voltage will happen if the input current is too large, leading to the degradation of the Li-battery's service life. To solve this problem, the inrush current is limited by introducing a new start-up state. All of the circuits have been implemented with the NUVOTON 0.6 μm CMOS process. The measurement results show that the inrush current can be limited below 1 A within all input supply ranges, and the power efficiency is higher than the conventional structure. Project supported by the National Natural Science Foundation of China (No. 61106026).

  20. A micro-power LDO with piecewise voltage foldback current limit protection

    Institute of Scientific and Technical Information of China (English)

    Wei Hailong; Liu Youbao; Guo Zhongjie; Liao Xue

    2012-01-01

    To achieve a constant current limit,low power consumption and high driving capability,a micro-power LDO with a piecewise voltage-foldback current-limit circuit is presented.The current-limit threshold is dynamically adjusted to achieve a maximum driving capability and lower quiescent current of only 300 nA.To increase the loop stability of the proposed LDO,a high impedance transconductance buffer under a micro quiescent current is designed for splitting the pole that exists at the gate of the pass transistor to the dominant pole,and a zero is designed for the purpose of the second pole phase compensation.The proposed LDO is fabricated in a BiCMOS process.The measurement results show that the short-circuit current of the LDO is 190 mA,the constant limit current under a high drop-out voltage is 440 mA,and the maximum load current under a low drop-out voltage is up to 800 mA.In addition,the quiescent current of the LDO is only 7 μA,the load regulation is about 0.56% on full scale,the line regulation is about 0.012%/V,the PSRR at 120 Hz is 58 dB and the drop-out voltage is only 70 mV when the load current is 250 mA.

  1. Charge Exchange Effect on Space-Charge-Limited Current Densities in Ion Diode

    Institute of Scientific and Technical Information of China (English)

    石磊

    2002-01-01

    The article theoretically studied the charge-exchange effects on space charge limited electron and ion current densities of non-relativistic one-dimensional slab ion diode, and compared with those of without charge exchange.

  2. Estimating Heat and Mass Transfer Processes in Green Roof Systems: Current Modeling Capabilities and Limitations (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Tabares Velasco, P. C.

    2011-04-01

    This presentation discusses estimating heat and mass transfer processes in green roof systems: current modeling capabilities and limitations. Green roofs are 'specialized roofing systems that support vegetation growth on rooftops.'

  3. Diabetes Mellitus and Cardiovascular Prevention: The Role and the Limitations of Currently Available Antiplatelet Drugs

    Directory of Open Access Journals (Sweden)

    A. Tufano

    2011-01-01

    This paper reviews the role of currently available antiplatelet drugs in primary and secondary prevention of vascular events in diabetic patients and the limitations of these drugs, and it discusses the role of novel and more potent antiplatelets and of new agents currently under clinical development.

  4. InP Gunn Diodes with Current Limiting Contact for High Efficiency Gunn Oscillators

    Science.gov (United States)

    Kim, Mi-Ra; Rhee, Jin-Koo; Lee, Chang-Woo; Chae, Yeon-Sik; Choi, Jae-Hyun; Kim, Wan-Joo

    We fabricated and examined current limiting effect for InP Gunn diodes with stable depletion layer mode operation of diodes for high efficiency Gunn oscillators. Current limiting at the cathode was achieved by a shallow Schottky barrier at the interface. We discussed fabrication procedure, the results for negative differential resistance and rf tests for InP Gunn diodes. It was shown that the fabricated Gunn diodes have the output power of 10.22dBm at a frequency of 90.13GHz. Its input voltage and corresponding current were 8.55V and 252mA, respectively.

  5. Over-limiting Current and Control of Dendritic Growth by Surface Conduction in Nanopores

    CERN Document Server

    Han, Ji-Hyung; Bai, Peng; Bazant, Martin Z

    2014-01-01

    Understanding over-limiting current (faster than diffusion) is a long-standing challenge in electrochemistry with applications in desalination and energy storage. Known mechanisms involve either chemical or hydrodynamic instabilities in unconfined electrolytes. Here, it is shown that over-limiting current can be sustained by surface conduction in nano pores, without any such instabilities, and used to control dendritic growth during electrodeposition. Copper electrode posits are grown in anodized aluminum oxide membranes with polyelectrolyte coatings to modify the surface charge. At low currents, uniform electroplating occurs, unaffected by surface modification due to thin electric double layers, but the morphology changes dramatically above the limiting current. With negative surface charge, growth is enhanced along the nanopore surfaces, forming surface dendrites and nanotubes behind a deionization shock. With positive surface charge, dendrites avoid the surfaces and are either guided along the nanopore cen...

  6. First experimental results with the Current Limit Avoidance System at the JET tokamak

    Energy Technology Data Exchange (ETDEWEB)

    De Tommasi, G. [Associazione EURATOM-ENEA-CREATE, Università di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); Galeani, S. [Dipartimento di Informatica, Sistemi e Produzione, Università di Roma, Tor Vergata, Rome (Italy); Jachmich, S. [Association EURATOM-Belgian State, Koninklijke Militaire School - Ecole Royale Militaire, B-1000 Brussels (Belgium); Joffrin, E. [IRFM-CEA, Centre de Cadarache, 13108 Saint-paul-lez-Durance (France); Lennholm, M. [EFDA Close Support Unit, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); European Commission, B-1049 Brussels (Belgium); Lomas, P.J. [Euratom-CCFE, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Neto, A.C. [Associazione EURATOM-IST, Instituto de Plasmas e Fusao Nuclear, IST, 1049-001 Lisboa (Portugal); Maviglia, F. [Associazione EURATOM-ENEA-CREATE, Via Claudio 21, 80125 Napoli (Italy); McCullen, P. [Euratom-CCFE, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Pironti, A. [Associazione EURATOM-ENEA-CREATE, Università di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); Rimini, F.G. [Euratom-CCFE, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Sips, A.C.C. [European Commission, B-1049 Brussels (Belgium); Varano, G.; Vitelli, R. [Dipartimento di Informatica, Sistemi e Produzione, Università di Roma, Tor Vergata, Rome (Italy); Zaccarian, L. [CNRS, LAAS, 7 Avenue du Colonel Roche, F-31400 Toulouse (France); Universitè de Toulouse, LAAS, F-31400 Toulouse (France)

    2013-06-15

    The Current Limit Avoidance System (CLA) has been recently deployed at the JET tokamak to avoid current saturations in the poloidal field (PF) coils when the eXtreme Shape Controller is used to control the plasma shape. In order to cope with the current saturation limits, the CLA exploits the redundancy of the PF coils system to automatically obtain almost the same plasma shape using a different combination of currents in the PF coils. In the presence of disturbances it tries to avoid the current saturations by relaxing the constraints on the plasma shape control. The CLA system has been successfully implemented on the JET tokamak and fully commissioned in 2011. This paper presents the first experimental results achieved in 2011–2012 during the restart and the ITER-like wall campaigns at JET.

  7. Multi-Soft gluon limits and extended current algebras at null-infinity

    CERN Document Server

    McLoughlin, Tristan

    2016-01-01

    In this note we consider aspects of the current algebra interpretation of multi-soft limits of tree-level gluon scattering amplitudes in four dimensions. Building on the relation between a positive helicity gluon soft-limit and the Ward identity for a level-zero Kac-Moody current, we use the double-soft limit to define the Sugawara energy-momentum tensor and, by using the triple- and quadruple-soft limits, show that it satisfies the correct OPEs for a CFT. We study the resulting Knizhnik-Zamolodchikov equations and show that they hold for positive helicity gluons in MHV amplitudes. Turning to the sub-leading soft-terms we define a one-parameter family of currents whose Ward identities correspond to the universal tree-level sub-leading soft-behaviour. We compute the algebra of these currents formed with the leading currents and amongst themselves. Finally, by parameterising the ambiguity in the double-soft limit for mixed helicities, we introduce a non-trivial OPE between the holomorphic and anti-holomorphic c...

  8. Improving Transient Recovery voltage of circuit breaker using Fault Current Limiter

    Directory of Open Access Journals (Sweden)

    Amir Heidary

    2012-12-01

    Full Text Available This study investigates influence of Fault Current Limiter (FCL on short-circuits current level of substation bus bar splitter circuit breaker and its TRV. An approach for TRV evaluation is developed and applied for proposed power system as shown in this study. FCL circuit is connected to the power system in order to limit TRV. The limiter circuit consists of two equal windings which are turned around unique magnetic core. One of the windings is connected in series with the power system network and the other is connected to the network via series capacitor and power electronic switches. During normal operating condition, both tyristors are in on state and current of the primary and secondary windings are equal. This causes zero impedance of the limiter. During fault, faults current cause the power electronic switch to turn off which increases the limiter impedance. By increasing the limiter impedance, amplitude of TRV decreases substantially. The novel method presented in this study is a cheap and successful scheme.

  9. Analysis and design of over-current limit control strategies applied in aeronautical power supplies

    Institute of Scientific and Technical Information of China (English)

    WANG Lin-bing; HE Xiang-ning

    2007-01-01

    Some Over-Current Limit Control strategies are analyzed and designed to meet the demands of high reliability and rapid dynamic response in the aeronautical power supply applications. The control schemes are both effective in DC-DC converters and DC-AC converters. Controller models are set up, and the over-current limit operation principles of analogy and digital control are analyzed too. An 800VA aeronautical power supply has been constructed to verify the performance of the proposed control strategy in various cases such as the sudden load change and the constant load. The analysis and experiments confirm the advantages of the proposed over-current limit strategies as follows: simple,effective and reliable.

  10. Current self-limitation in a transverse nanosecond discharge with a slotted cathode

    Science.gov (United States)

    N, A. ASHURBEKOV; K, O. IMINOV; O, A. POPOV; G, S. SHAKHSINOV

    2017-03-01

    A high-voltage transverse pulsed nanosecond discharge with a slotted hollow cathode was found to be a source of high-energy (few kV) ribbon electron beams. Conditions for the formation and extinction of electron beams were experimentally studied in discharges in helium at pressures of 1–100 Torr. It was found that interaction of fast electrons with a non-uniform electric field near the slotted cathode led to limitation of the magnitude of the discharge current. A physical model was developed to describe the discharge current self-limitation that was in satisfactory agreement with the experimental results. Some technical solutions that are expected to increase the upper current limits in transverse nanosecond discharge are discussed.

  11. On-chip temperature monitoring of a SiC current limiter

    Energy Technology Data Exchange (ETDEWEB)

    Tournier, D.; Godignon, P.; Millan, J. [Centro Nacional de Microelectronica (CNM), Univ. Autonoma de Barcelona, Bellaterra (Spain); Planson, D.; Chante, J.P. [Centre de Genie Electrique de Lyon (CEGELY) INSA-LYON, UMR 5005 CNRS, Villeurbanne (France); Sarrus, F.; Palma, J.F. de [Ferraz Shawmut, Bonnet de Mure (France)

    2004-07-01

    High voltage and high current potentiality of SiC based devices has been proved, and various devices able to work at high temperature have been reported as well. Nevertheless, packaging is one of the main constrains for high temperature operation of these devices. Up to date, no specific power package has been reported for high temperature operation. Moreover, it is desirable to predict the SiC die temperature to avoid any related failure in order to improve the efficiency of the packaged SiC device. This paper deals with an integrated temperature sensor for SiC current limiting devices. The current limiter is based on a VJFET structure, which capability for dissipating high power density (140 kW/cm{sup 2}), in the limiting state, has been previously demonstrated. Carrier mobility dependence with temperature was extracted from cryogenic measurements. The temperature estimation is based on the measurement of the variation of the electrical resistance (caused by mobility variation) of the sensing device integrated with the current limiter. In this paper we first describe the temperature estimation methodology using various technological solution (from metallic resistor solution to the SiC integrated sensor). Then experimental temperature measurements using an integrated SiC sensor within a packaged current limiting devices will be presented. Electro-thermal measurements on the fabricated devices show that the current limiter is able to work at 205 C under steady state conditions (320 V), without degrading their electrical performances. Finally, perspectives in terms of integration and reliability will be proposed. (orig.)

  12. Modeling the Non Linear Behavior of a Magnetic Fault Current Limiter

    Directory of Open Access Journals (Sweden)

    P. R. Wilson

    2015-11-01

    Full Text Available Fault Current Limiters are used in a wide array of applications from small circuit protection at low power levels to large scale high power applications which require superconductors and complex control circuitry. One advantage of  passive fault current limiters (FCL is the automatic behavior that is dependent on the intrinsic properties of the circuit elements rather than on a complex feedback control scheme making this approach attractive for low cost applications and also where reliability is critical. This paper describes the behavioral modeling of a passive Magnetic FCL and its potential application in practical circuits.

  13. Two-dimensional relativistic space charge limited current flow in the drift space

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y. L.; Chen, S. H., E-mail: chensh@ncu.edu.tw [Department of Physics, National Central University, Jhongli 32001, Taiwan (China); Koh, W. S. [A-STAR Institute of High Performance Computing, Singapore 138632 (Singapore); Ang, L. K. [Engineering Product Development, Singapore University of Technology and Design, Singapore 138682 (Singapore)

    2014-04-15

    Relativistic two-dimensional (2D) electrostatic (ES) formulations have been derived for studying the steady-state space charge limited (SCL) current flow of a finite width W in a drift space with a gap distance D. The theoretical analyses show that the 2D SCL current density in terms of the 1D SCL current density monotonically increases with D/W, and the theory recovers the 1D classical Child-Langmuir law in the drift space under the approximation of uniform charge density in the transverse direction. A 2D static model has also been constructed to study the dynamical behaviors of the current flow with current density exceeding the SCL current density, and the static theory for evaluating the transmitted current fraction and minimum potential position have been verified by using 2D ES particle-in-cell simulation. The results show the 2D SCL current density is mainly determined by the geometrical effects, but the dynamical behaviors of the current flow are mainly determined by the relativistic effect at the current density exceeding the SCL current density.

  14. Regge limit of R-current correlators in AdS supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Bartels, J.; Kotanski, J.; Mischler, A.M. [II. Inst. fuer Theoretische Physik, Univ. Hamburg (Germany); Schomerus, V. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2009-08-15

    Four-point functions of R-currents are discussed within Anti-de Sitter supergravity. In particular, we compute Witten diagrams with graviton and gauge boson exchange in the high energy Regge limit. Assuming validity of the AdS/CFT correspondence, our results apply to R-current four-point functions of N=4 super Yang-Mills theory at strong coupling. (orig.)

  15. Surveillance of fetal arrhythmias in the outpatient setting: current limitations and call for action.

    Science.gov (United States)

    Freire, Grace

    2015-12-01

    Surveillance of fetal arrhythmias in the outpatient setting remains limited by lack of monitoring modalities. Despite technological advances made in the field of obstetrics, existing devices are not currently suitable to monitor fetal arrhythmias. In this report, the author describes the current and developing fetal heart rate monitoring technologies including the recent introduction of hand-held Doppler monitors for outpatient surveillance of fetal arrhythmias.

  16. Virtual Impedance Based Fault Current Limiters for Inverter Dominated AC Microgrids

    DEFF Research Database (Denmark)

    Lu, Xiaonan; Wang, Jianhui; Guerrero, Josep M.

    2017-01-01

    In this paper, a virtual impedance based fault current limiter (VI-FCL) is proposed for islanded microgrids comprised of multiple inverter interfaced distributed generators (DGs). Considering the increased fault current capability induced by high penetration of renewable energy sources (RESs), FC......, and the stability analysis in consideration of VI-FCLs is thereby studied. MATLAB/Simulink model comprised of three inverter-interfaced DGs is implemented to verify the feasibility of the proposed method....

  17. Simple voltage-controlled current source for wideband electrical bioimpedance spectroscopy: circuit dependences and limitations

    Science.gov (United States)

    Seoane, F.; Macías, R.; Bragós, R.; Lindecrantz, K.

    2011-11-01

    In this work, the single Op-Amp with load-in-the-loop topology as a current source is revisited. This circuit topology was already used as a voltage-controlled current source (VCCS) in the 1960s but was left unused when the requirements for higher frequency arose among the applications of electrical bioimpedance (EBI). The aim of the authors is not only limited to show that with the currently available electronic devices it is perfectly viable to use this simple VCCS topology as a working current source for wideband spectroscopy applications of EBI, but also to identify the limitations and the role of each of the circuit components in the most important parameter of a current for wideband applications: the output impedance. The study includes the eventual presence of a stray capacitance and also an original enhancement, driving with current the VCCS. Based on the theoretical analysis and experimental measurements, an accurate model of the output impedance is provided, explaining the role of the main constitutive elements of the circuit in the source's output impedance. Using the topologies presented in this work and the proposed model, any electronic designer can easily implement a simple and efficient current source for wideband EBI spectroscopy applications, e.g. in this study, values above 150 kΩ at 1 MHz have been obtained, which to the knowledge of the authors are the largest values experimentally measured and reported for a current source in EBI at this frequency.

  18. Superhydrophobic SAM Modified Electrodes for Enhanced Current Limiting Properties in Intrinsic Conducting Polymer Surge Protection Devices.

    Science.gov (United States)

    Jabarullah, Noor H; Verrelli, Emanuele; Mauldin, Clayton; Navarro, Luis A; Golden, Josh H; Madianos, Leonidas M; Kemp, Neil T

    2015-06-09

    Surface interface engineering using superhydrophobic gold electrodes made with 1-dodecanethiol self-assembled monolayer (SAM) has been used to enhance the current limiting properties of novel surge protection devices based on the intrinsic conducting polymer, polyaniline doped with methanesulfonic acid. The resulting devices show significantly enhanced current limiting characteristics, including current saturation, foldback, and negative differential effects. We show how SAM modification changes the morphology of the polymer film directly adjacent to the electrodes, leading to the formation of an interfacial compact thin film that lowers the contact resistance at the Au-polymer interface. We attribute the enhanced current limiting properties of the devices to a combination of lower contact resistance and increased Joule heating within this interface region which during a current surge produces a current blocking resistive barrier due to a thermally induced dedoping effect caused by the rapid diffusion of moisture away from this region. The effect is exacerbated at higher applied voltages as the higher temperature leads to stronger depletion of charge carriers in this region, resulting in a negative differential resistance effect.

  19. InGaAs-InP avalanche photodiodes with dark current limited by generation-recombination.

    Science.gov (United States)

    Zhao, Yanli; Zhang, Dongdong; Qin, Long; Tang, Qi; Wu, Rui Hua; Liu, Jianjun; Zhang, Youping; Zhang, Hong; Yuan, Xiuhua; Liu, Wen

    2011-04-25

    Separate absorption grading charge multiplication avalanche photodiodes (SAGCM APDs) are widely accepted in photon starved optical communication systems due to the presence of large photocurrent gain. In this work, we present a detailed analysis of dark currents of planar-type SAGCM InGaAs-InP APDs with different thicknesses of multiplication layer. The effect of the diffusion process, the generation-recombination process, the tunneling process and the multiplication process on the total leakage current is discussed. A new empirical formula has been established to predict the optimal multiplication layer thickness of SAGCM APDs with dark current limited by generation-recombination at multiplication gain of 8.

  20. THE MATHEMATIC MODEL OF POTENTIAL RELAXATION IN COULOSTATIC CONDITIONS FOR LIMITING DIFFUSION CURRENT CASE

    Directory of Open Access Journals (Sweden)

    O. H. Kapitonov

    2010-05-01

    Full Text Available A mathematical model of coulostatic relaxation of the potential for solid metallic electrode was presented. The solution in the case of limiting diffusion current was obtained. On the basis of this model the technique of concentration measurements for heavy metal ions in diluted solutions was suggested. The model adequacy was proved by experimental data.

  1. Limiting Current of Oxygen Reduction on Gas-Diffusion Electrodes for Phosphoric Acid Fuel Cells

    DEFF Research Database (Denmark)

    Li, Qingfeng; Gang, Xiao; Hjuler, Hans Aage;

    1994-01-01

    Various models have been devoted to the operation mechanism of porous diffusion electrodes. They are, however, suffering from the lack of accuracy concerning the acid-film thickness on which they are based. In the present paper the limiting current density has been measured for oxygen reduction...... on polytetrafluorine-ethyl bonded gas-diffusion electordes in phosphoric acid with and without fluorinated additives. This provides an alternative to estimate the film thickness by combining it with the acid-adsorption measurements and the porosity analysis of the catalyst layer. It was noticed that the limiting...... expression for the limiting current density. The acid-film thickness estimated this way was found to be of 0.1 mum order of magnitude for the two types of electrodes used in phosphoric acid with and without fluorinated additives at 150-degrees-C....

  2. Predicting size effect on diffusion-limited current density of oxygen reduction by copper wire

    Institute of Scientific and Technical Information of China (English)

    LU Yonghong; XU Haibo; WANG Jia; ZHONG Lian

    2011-01-01

    The size effect of copper wire radius (0.04鈥?.82 mm) on the diffusion-limited current density of an oxygen reduction reaction in stagnant simulated seawater (naturally aerated 0.5 mol/L NaCl) is investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) and compared with the results obtained in 0.5 mol/L H2SO4. In the oxygen diffusion-limited range, size effect is found to occur independent of electrolytes, which is attributed to non-linear diffusion. Additionally, to satisfy application in a marine setting, an empirical equation correlating oxygen diffusion-limited current density to copper wire radius is proposed by fitting experimental data.

  3. Analysis of the effects of asymmetric faults in three-phase superconducting inductive fault current limiters

    Science.gov (United States)

    Ferreira, R.; Pina, J. M.; Vilhena, N.; Arsénio, P.; Pronto, A. G.; Martins, J.

    2014-05-01

    Inductive fault current limiters of magnetic shielding type can be described in terms of the excursion in the plane defined by flux linked with primary and line current, and this methodology has been previously applied to single-phase devices. Practical applications, however, require three-phase limiters, which, for the sake of compactness, may be built by three legged cores, instead of three single phase units. This has the advantage of using well established methods of power transformers industry, but the performance of the devices depends on the type of fault, e.g. phase to ground or phase to phase. For instance, in a three legged core, a phase to ground fault affects healthy phases, and these are the most frequent faults in distribution grids, where such systems are envisaged. The effects of asymmetric faults are analysed in this paper, by means of measured excursions in the linked flux-current plane.

  4. Inrush Current Limitation in Wind Generators by SCR Based Soft-starter during grid connection

    Directory of Open Access Journals (Sweden)

    Sanjay Mishra

    2013-10-01

    Full Text Available High Inrush current & harmonics is a generic problem wind generators during grid connection.The designed SCR based soft-starter successfully limits the high inrush current during the connection of the wind-turbine system to the grid. The proposed SCR based soft starter using will be simulating in PSCAD on a three-phase induction generator. Expected results will show a significant reduction in high inrush current and smooth connection of the three phase induction generator to the grid with small impact on the power quality. A small-scale wind turbine coupled three phase induction generator is an attractive choice for an isolated grid hybrid power system in remote areas because of its low cost, compactness, ruggedness, high reliability, low inertia and ease in control. In this work, a SCR based soft starter for limiting the high inrush current during the connection of the small-scale wind turbine coupled three phase induction generator to an isolated weak grid has been proposed. Soft-starter is designed to reduce inrush current or surge in current while achieving a proper synchronism between the generator and the grid.

  5. Enhancement of transient stability using fault current limiter and braking resistor

    Energy Technology Data Exchange (ETDEWEB)

    Yagami, M.; Hiratsuka, Y. [Hokkaido Inst. of Technology, Sapporo, Hokkaido (Japan); Tamura, J. [Kitami Inst. of Technology, Kitami, Hokkaido (Japan)

    2006-07-01

    Replacement of aging substation equipment is needed in order to maintain the stability of electric power systems which are becoming increasingly interconnected. This paper addressed the issue of using fault current limiters (FCLs) as a means of limiting fault currents and enhancing the transient stability of a power system. FCL limits the fault current by generating an impedance when a fault occurs. The limiting impedance helps to increase generator output degraded by a fault, thus providing stabilization. However, FCLs installed in series with transmission lines can only be operated during the period from the fault occurrence to the fault clearing. Therefore, they cannot control the generator disturbances after the clearing of a fault. However, in the event of power failures, thyristor controlled braking resistors (TCBRs) can quickly control generator disturbances. Therefore, the authors proposed the use of both FCL and TCBR devices to enhance transient stability and damp the turbine shaft torsional oscillations. The effectiveness of both devices on suppression of the turbine shaft torsional oscillations was illustrated through simulations performed in EMTP/ATP considering three-lines-to-ground fault. It was shown that if both devices operate at the same bus, the stabilization control scheme can be carried out continuously and with flexibility from the fault occurrence instance, thereby effectively improving transient stability. 7 refs., 2 tabs., 10 figs.

  6. Current Limitations and Recommendations to Improve Testing for the Environmental Assessment of Endocrine Active Substances

    DEFF Research Database (Denmark)

    Coady, Katherine K; Biever, Ronald C; Denslow, Nancy D

    2016-01-01

    evaluate whether a chemical possesses endocrine activity and whether this activity can result in adverse outcomes either to humans or the environment. Current test systems include in silico, in vitro and in vivo techniques focused on detecting potential endocrine activity, and in vivo tests that collect...... apical data to detect possible adverse effects. These test systems are currently designed to robustly assess endocrine activity and/or adverse effects in the estrogen, androgen, and thyroid hormone signaling pathways; however, there are some limitations of current test systems for evaluating endocrine...... methods currently do not exist, and addressing key endocrine pathways of possible concern in addition to those associated with estrogen, androgen and thyroid signaling. This article is protected by copyright. All rights reserved....

  7. Review on Superconducting Fault Current Limiters%超导限流器综述

    Institute of Scientific and Technical Information of China (English)

    信赢

    2015-01-01

    This paper briefly recalls the scientific origin and R&D history of superconducting fault current limiters. The working princi-ple, generic structure, and equivalent circuitry of resistive type, saturated iron-core type, magnetic shield type, and bridge type super-conducting fault current limiters are introduced. The functional characteristics, technical advantages and disadvantages of resistive type and saturated iron-core type superconducting fault current limiters are analyzed and compared in detail. Real grid application examples of these two types of devices are presented. Discussing the application scope and prospect of superconducting fault current limiters, the paper points out that besides conventional fault current limiting functions, superconducting fault current limiters may become an indis-pensable device in grid integration of distributed renewable generations, and they will play an important role in upgrading power grids by reducing transmission loss and enhancing efficiency in the future.%概述了超导限流器的科学基础和发展历史,介绍了电阻型、饱和铁心型、磁屏蔽性和电桥型超导限流器的技术原理、基本结构和等效电路,详细分析和比较了电阻型和饱和铁心型超导限流器的性能特征、优点和缺点,以及其在实际电网挂网运行的案例。展望了超导限流器可能的应用范围及前景,指出除了传统观念上的短路故障限流作用之外,超导限流器未来可能成为可再生能源分布式发电并网的必要设备,在降低输电损耗和提高输送效率方面发挥重要作用。

  8. Research on a Fast-Closing Switch Based Fault Current Limiter with Series Compensation

    Institute of Scientific and Technical Information of China (English)

    CHEN Jin-xiang; ZOU Ji-yan; DONG En-yuan; SHI Jing

    2002-01-01

    A new type of fault current limiter (FCL) with series compensation based fast-closing switch is proposed. It is composed of a capacitor bank and a reactor in series.The main control component is a fast-closing switch connected in parallel with the capacitors, which is driven by the electromagnetic repulsion force. When fault occurs, the switch closes and bypasses the capacitors,and the fault is limited by the reactor then. Simulated analysis and experiments show that it is feasible to develop the FCL with low cost and high reliability. The effectiveness of transient stability for power system is evaluated by digital simulation.

  9. Impact and Limitations Deriving from Basel II within the Context of the Current Financial Crisis

    Directory of Open Access Journals (Sweden)

    Oana Miruna DĂNILĂ

    2012-06-01

    Full Text Available The Banking sector risk management framework, geared towards maintaining a solid capital adequacy level, has witnessed a permanent evolution, determined by the global economic and financial reality.Basel II has brought an improvement of the risk management framework by adding minimum capital levels corresponding to market and operational risk and by the introduction of internal rating models. However the current crisis has brought forward some adverse effects as well as limitations.This paper analyses the evolution of prudential rules and regulations introduced by Basel II and their impact on the banking system together with outlining certain limitations.

  10. Limitations of absolute current densities derived from the Semel & Skumanich method

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Semel and Skumanich proposed a method to obtain the absolute electric current density, |Jz|, without disambiguation of 180° in the transverse field directions. The advantage of the method is that the uncertainty in the determination of the ambiguity in the magnetic azimuth is removed. Here, we investigate the limits of the calculation when applied to a numerical MHD model. We have found that the combination of changes in the magnetic azimuth with vanishing horizontal field component leads to errors, where electric current densities are often strong. Where errors occur, the calculation gives |Jz| too small by factors typically 1.2 - 2.0.

  11. Predicting the behavioural impact of transcranial direct current stimulation: issues and limitations

    Directory of Open Access Journals (Sweden)

    Archy Otto De Berker

    2013-10-01

    Full Text Available The transcranial application of weak currents to the human brain has enjoyed a decade of success, providing a simple and powerful tool for non-invasively altering human brain function. However, our understanding of current delivery and its impact upon neural circuitry leaves much to be desired. We argue that the credibility of conclusions drawn with tDCS is contingent upon realistic explanations of how tDCS works, and that our present understanding of tDCS limits the technique’s use to localize function in the human brain. We outline two central issues where progress is required: the localization of currents, and predicting their functional consequence. We encourage experimenters to eschew simplistic explanations of mechanisms of transcranial current stimulation. We suggest the use of individualized current modelling, together with computational neurostimulation to inform mechanistic frameworks in which to interpret the physiological impact of tDCS. We hope that through mechanistically richer descriptions of current flow and action, insight into the biological processes by which transcranial currents influence behaviour can be gained, leading to more effective stimulation protocols and empowering conclusions drawn with tDCS.

  12. A dulal-functional medium voltage level DVR to limit downstream fault currents

    DEFF Research Database (Denmark)

    Li, Yun Wei; Vilathgamuwa, D. Mahinda; Loh, Poh Chiang

    2007-01-01

    , the DVR will therefore be tasked to mitigate even more faults involving downstream loads. Large fault currents would flow through the DVR during a downstream fault before the opening of a circuit breaker. This will cause the voltage at point of common coupling (PCC) to drop, which would affect the loads...... on the other parallel feeders connected to PCC. Furthermore, if not controlled properly, the DVR might also contribute to this PCC voltage sag in the process of compensating the missing voltage, thus further worsening the fault situation. To limit the flow of large line currents, and therefore restore the PCC...... voltage as well as protect the DVR system components, a downstream fault limiting function is proposed and integrated in the DVR operation. A flux-charge-model feedback algorithm is implemented so that the DVR would act as a large virtual inductance in series with the distribution feeder in fault...

  13. Study of the Fast—Closing Switch Used for Fault Current Limiters in Power System

    Institute of Scientific and Technical Information of China (English)

    邹积岩; 陈金祥; 等

    2002-01-01

    This paper presents a new type of fault current limiter(FCL) based on fast-closing switch,which is composed of a capacitor bank and a reactor in series.The main control component is a fast-closing switch connected in parallel with the capactitors,which is drien by the electromagnetic repulsion force.It can response the order within 1 ms.When fault occurs,the switch closes and the capacitors are bypassed.and the fault current is limited by the reactor,Simulation analysis and experiment show that the electromagnetic repulsion force actuator can meet the demand of fast-closing switch,it is feasible to develop the FCL with low cost and high reliability.

  14. Current-limiting reactor based on high-T sub c superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Bashkirov, Y.A.; Fleishman, L.S.; Patsayeve, T.Y.; Sobolev, A.N.P; Vdovin, A.B. (Krzhizhanovsky Power Engineering Inst., Leninsky prospect, 19, Moscow 117927 (SU))

    1991-03-01

    This paper deals with one of the possible applications of high-temperature superconductors in power devices with superconducting shields. The behavior was analyzed of a current-limiting reactor combining a high-T{sub c} shield and an iron core in an a.c. circuit. The model of the device was built comprising a stack of yttrium ceramic rings. The experiments with such a reactor confirmed the presence of nonlinear characteristics with transition from low to high impedance.

  15. Transformation of current limiting effect into varistor effect in tin dioxide based ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Bondarchuk, A N; Glot, A B [Universidad Tecnologica de la Mixteca, Huajuapan de Leon, Oaxaca, C.P. 69000 (Mexico)], E-mail: alexbond@mixteco.utm.mx

    2008-09-07

    The current limiting effect and its transformation into the varistor effect were found in SnO{sub 2}-Co{sub 3}O{sub 4}-Nb{sub 2}O{sub 5}-Cr{sub 2}O{sub 3} ceramics sintered at relatively low temperatures 1100-1200 {sup 0}C. Results of electrical measurements in oxidizing and inert atmosphere are explained in terms of the modified barrier model.

  16. Limiting current technique in the research of mass/heat transfer in nanofluid

    Science.gov (United States)

    Wilk, J.; Grosicki, S.

    2016-09-01

    In the paper the authors focused on the application of the electrochemical limiting diffusion current technique to the study of mass transfer in nanofluid flow. As mass and heat transfer are analogical phenomena, analysing mass transfer helps understand heat transfer processes in nanofluids. The paper begins with a short review of the available literature on the subject followed by the authors' results of mass transfer coefficient measurements and the conclusions concerning mass/heat transfer enhancement in nanofluids.

  17. Current meter data from moored current meter casts in the Northeast Pacific (limit - 180) from 12 June 1992 - 20 June 1994 (NODC Accession 9700237)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter data were collected using moored current meter casts in the Northeast Pacific (limit - 180) from June 12, 1992 to June 20, 1994. Data were submitted by...

  18. Current components data from current meters from the NE Pacific (limit-180) from 01 June 1954 to 01 June 1970 (NODC Accession 7601441)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current components data were collected from current meters in the NE Pacific (limit-180). Data were collected by the Japanese Hydrographic Office from 01 June 1954...

  19. Limiting current density in bis(trifluoromethylsulfonyl)amide-based ionic liquid for lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jun-Woo; Yoshida, Kazuki; Tachikawa, Naoki; Dokko, Kaoru; Watanabe, Masayoshi [Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan)

    2011-02-15

    The physicochemical and electrochemical properties of the binary ionic liquid (IL), lithium bis(trifluoromethylsulfonyl)amide (LiTFSA) dissolved in N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl)amide (DEMETFSA), were investigated. The ionic conductivity of the binary IL decreased with an increase in LiTFSA concentration. The self-diffusion coefficients of Li{sup +}, DEME{sup +}, and TFSA{sup -} dissolved in the IL were measured by using the pulsed-field-gradient spin-echo (PGSE) NMR method. The self-diffusion coefficient of each ionic species was also found to decrease with increasing concentration of LiTFSA. The limiting current density in the IL electrolyte was evaluated by chronoamperometry using symmetric Li vertical stroke IL vertical stroke Li cell. The results suggest that the diffusion process of Li(I) in the IL dominates the limiting current density in the cell. The highest limiting current density is achieved at a concentration of 0.64 mol dm{sup -3} of LiTFSA. (author)

  20. Functional limitations linked to high body mass index, age and current pain in obese women.

    Science.gov (United States)

    Evers Larsson, U; Mattsson, E

    2001-06-01

    To describe functional limitations in obese women. Comparisons of functional limitations in obese women and in a normal-weight reference group regarding mobility, balance and housework transport. A large room with a corridor and staircase nearby. Fifty-seven consecutively selected obese female outpatients, mean age 44 y, body mass index (BMI) 37 kg.m(-2), and 22 voluntary references, mean age 49 y, BMI 22 kg.m(-2). Pain questionnaire (for background data); a new valid and reliable test protocol measuring activities of daily life (ADL), pain and exertion, heart rate, balance and speed. The patients had problems in performing 13 of 16 actions compared with the references (P-values between 0.05 and 0.001). They moved more slowly and had difficulties and /or pain and exertion in flexibility tasks, balancing, activities at floor level (bending and kneeling), climbing stairs and carrying groceries. BMI (P=0.002), age (P=0.02) and current pain (P=0.02) from the lower body predicted functional limitation. The functional test reflected functional limitations in obese women, revealing difficulties and perceived pain in ADL. The test protocol can be used to evaluate the effects of training or dieting. For clinical use we recommend considering BMI, age and current pain for use when individualizing advice on training.

  1. Operation Tests for SN Transition Superconducting Fault Current Limiter in the Power System Simulator

    Science.gov (United States)

    Kameda, Hideyuki; Torii, Shinji; Kumano, Teruhisa; Sakaki, Hisayoshi; Kubota, Hiroshi; Yasuda, Kenji

    One of important problems to be solved in Japanese trunk transmission systems is the reduction of short circuit capacity. As this countermeasure, double buses are split into two buses in some substations. In recent years, dispersed generators are introduced in lower voltage classes due to the introduction of the electricity deregulation. In such a distribution system as many dispersed generators are introduced, it is a possibility that the fault current becomes beyond the breaking capacity at the occurrence of short circuit. Introduction of superconducting fault current limiters into a power system is very effective as one of the means to solve the above-mentioned problem, and we have studied on the effective introduction method of them and setting method of their parameters. This paper describes the results of the operation tests for SN transition type of a superconducting fault current limiter using 3 phases of FCL modules against various kinds of system faults or inrush current in the Power System Simulator installed at CRIEPI.

  2. Limitations Of The Current State Space Modelling Approach In Multistage Machining Processes Due To Operation Variations

    Science.gov (United States)

    Abellán-Nebot, J. V.; Liu, J.; Romero, F.

    2009-11-01

    The State Space modelling approach has been recently proposed as an engineering-driven technique for part quality prediction in Multistage Machining Processes (MMP). Current State Space models incorporate fixture and datum variations in the multi-stage variation propagation, without explicitly considering common operation variations such as machine-tool thermal distortions, cutting-tool wear, cutting-tool deflections, etc. This paper shows the limitations of the current State Space model through an experimental case study where the effect of the spindle thermal expansion, cutting-tool flank wear and locator errors are introduced. The paper also discusses the extension of the current State Space model to include operation variations and its potential benefits.

  3. Enhancing LVRT of DFIG by Using a Superconducting Current Limiter on Rotor Circuit

    Directory of Open Access Journals (Sweden)

    Flávio Oliveira

    2015-12-01

    Full Text Available This paper have studied the dynamic of a 2.0 MW Doubly Fed Induction Generator (DFIG during a severe voltage sag. Using the dynamic model of a DFIG, it was possible to determine the current, Electromagnetic Force and flux behavior during three-phase symmetrical voltage dip. Among the technologies of wind turbines the DFIG is widely employed; however, this machine is extremely susceptible to disturbances from the grid. In order to improve DFIG Low Voltage Ride-Through (LVRT, it is proposed a novel solution, using Superconducting Current Limiter (SCL in two arrangements: one, the SCL is placed between the machine rotor and the rotor side converter (RSC, and another placed in the RSC DC-link. The proposal is validated through simulation using PSCAD™/EMTDC™ and according to requirements of specific regulations. The analysis ensure that both SCL arrangements behave likewise, and are effective in decrement the rotor currents during the disturbance.

  4. Current Treatment of Bacterial Vaginosis—Limitations and Need for Innovation

    Science.gov (United States)

    Bradshaw, Catriona S.; Sobel, Jack D.

    2016-01-01

    Practitioners and patients alike widely recognize the limitations of current therapeutic approaches to the treatment of bacterial vaginosis (BV). Options remain extremely limited, and our inability to prevent the frequently, often relentless symptomatic recurrences of BV and to reduce serious sequelae such as preterm delivery, remains an acknowledged but unresolved shortcoming. Our incomplete understanding of the pathophysiology of this unique form of vaginal dysbiosis has been a significant impediment to developing optimal treatment and prevention approaches. New drugs have not been forthcoming and are not likely to be available in the immediate future; hence, reliance on the optimal use of available agents has become essential as improvised often unproven regimens are implemented. In this review, we will explore the limitations of currently recommended therapies, with a particular focus on the contribution of reinfection and pathogen persistence to BV recurrence, and the development of interventions that target these mechanisms. Ultimately, to achieve sustained cure and effectiveness against BV-associated sequelae, it is possible that we will need approaches that combine antimicrobials with biofilm-disrupting agents and partner treatments in those at risk of reinfection. PMID:27449869

  5. Current Treatment of Bacterial Vaginosis-Limitations and Need for Innovation.

    Science.gov (United States)

    Bradshaw, Catriona S; Sobel, Jack D

    2016-08-15

    Practitioners and patients alike widely recognize the limitations of current therapeutic approaches to the treatment of bacterial vaginosis (BV). Options remain extremely limited, and our inability to prevent the frequently, often relentless symptomatic recurrences of BV and to reduce serious sequelae such as preterm delivery, remains an acknowledged but unresolved shortcoming. Our incomplete understanding of the pathophysiology of this unique form of vaginal dysbiosis has been a significant impediment to developing optimal treatment and prevention approaches. New drugs have not been forthcoming and are not likely to be available in the immediate future; hence, reliance on the optimal use of available agents has become essential as improvised often unproven regimens are implemented. In this review, we will explore the limitations of currently recommended therapies, with a particular focus on the contribution of reinfection and pathogen persistence to BV recurrence, and the development of interventions that target these mechanisms. Ultimately, to achieve sustained cure and effectiveness against BV-associated sequelae, it is possible that we will need approaches that combine antimicrobials with biofilm-disrupting agents and partner treatments in those at risk of reinfection. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  6. A Practical Study of the 66kV Fault Current Limiter (FCL) System with Rectifier

    Science.gov (United States)

    Tokuda, Noriaki; Matsubara, Yoshio; Yuguchi, Kyosuke; Ohkuma, Takeshi; Hobara, Natsuro; Takahashi, Yoshihisa

    A fault current limiter (FCL) is extensively expected to suppress fault current, particularly required for trunk power systems heavily connected high-voltage transmission lines, such as 500kV class power system which constitutes the nucleus of the electric power system. By installing such FCL in the power system, the system interconnection is possible without the need to raise the capacity of the circuit breakers, and facilities can be configured for efficiency, among other benefits. For these reasons, fault current limiters based on various principles of operation have been developed both in Japan and abroad. In this paper, we have proposed a new type of FCL system, consisting of solid-state diodes, DC coil and bypass AC coil, and described the specification of distribution power system and 66kV model at the island power system and the superconducting cable power system. Also we have made a practical study of 66kV class, which is the testing items and the future subjects of the rectifier type FCL system.

  7. Limiter

    Science.gov (United States)

    Cohen, S.A.; Hosea, J.C.; Timberlake, J.R.

    1984-10-19

    A limiter with a specially contoured front face is provided. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution. This limiter shape accommodates the various power scrape-off distances lambda p, which depend on the parallel velocity, V/sub parallel/, of the impacting particles.

  8. High-temperature superconducting fault-current limiter - optimisation of superconducting elements

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    This report summarises the findings of a study initiated to continue the work of a DTI-LINK Collaborative Research Programme 'Enhancing the Properties of Bulk High Temperature Superconductors and their Potential Application as Fault Current Limiters (FCL). Details are given of computer modelling of the quenching process involving the transition from superconducting to normal conducting states undergone by the material when large currents are present. The design of compound elements, and a multi-element model are described along with FCL design covering distribution bus-coupler, embedded generator connection, larger generator connection, hazardous area safety, and interconnection to fault-prone network. The evaluation of thermal loss, test equipment and schedule, the optimised element, installed cost data, and the UK market are considered.

  9. Assessment of the impact of HTSCs on superconducting fault-current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Giese, R.F. [Argonne National Lab., IL (United States); Runde, M. [Energiforsyningens Forskningsinstitutt A/S, Trondheim (Norway)

    1993-03-01

    The possible impact of nitrogen-cooled superconductors on the desip and cost of superconducting fault-current limiters is assessed by considering the technical specifications such devices must meet and by comparing material properties of 77-K and 4-K superconductors. The main advantages of operating superconductors at 77 K are that the refrigeration operating cost is reduced by a factor of up to 25 and the refrigeration capital cost is reduced by a factor of up to 10. The heat capacity is several orders of magnitude Larger at 77 K and at 4 K. This phenomenon increases conductor stability against flux jumps but makes switching from the superconducting to the normal state slow and difficult. Therefore, a high critical current density, probably at least 10{sup 5} A/cm{sup 2}, is required.

  10. A Current Limiting Strategy to Improve Fault Ride-Through of Inverter Interfaced Autonomous Microgrids

    DEFF Research Database (Denmark)

    Sadeghkhani, Iman; Esmail Hamedani Golshan, Mohamad; Guerrero, Josep M.

    2017-01-01

    With high penetration of distributed energy resources (DER), fault management strategy is of great importance for the distribution network operation. The objective of this paper is to propose a current and voltage limiting strategy to enhance fault ride-through (FRT) capability of inverter......-based islanded microgrids (MGs) in which the effects of inverter control system and inverter topology (four/three-wire) are considered. A threephase voltage-sourced inverter (VSI) with multi-loop control system implemented in synchronous, stationary, and natural reference frames is employed in this study...... for both four- and three-wire configurations. The proposed strategy provides high voltage and current quality during overcurrent conditions, which is necessary for sensitive loads. Several time-domain simulation studies are conducted to investigate the FRT capability of the proposed strategy against both...

  11. Modeling space-charge-limited currents in organic semiconductors: Extracting trap density and mobility

    KAUST Repository

    Dacuña, Javier

    2011-11-28

    We have developed and have applied a mobility edge model that takes drift and diffusion currents to characterize the space-charge-limited current in organic semiconductors into account. The numerical solution of the drift-diffusion equation allows the utilization of asymmetric contacts to describe the built-in potential within the device. The model has been applied to extract information of the distribution of traps from experimental current-voltage measurements of a rubrene single crystal from Krellner showing excellent agreement across several orders of magnitude in the current. Although the two contacts are made of the same metal, an energy offset of 580 meV between them, ascribed to differences in the deposition techniques (lamination vs evaporation) was essential to correctly interpret the shape of the current-voltage characteristics at low voltage. A band mobility of 0.13cm 2V-1s-1 for holes is estimated, which is consistent with transport along the long axis of the orthorhombic unit cell. The total density of traps deeper than 0.1 eV was 2.2×1016cm -3. The sensitivity analysis and error estimation in the obtained parameters show that it is not possible to accurately resolve the shape of the trap distribution for energies deeper than 0.3 eV or shallower than 0.1 eV above the valence-band edge. The total number of traps deeper than 0.3 eV, however, can be estimated. Contact asymmetry and the diffusion component of the current play an important role in the description of the device at low bias and are required to obtain reliable information about the distribution of deep traps. © 2011 American Physical Society.

  12. Design, Test and Demonstration of Saturable Reactor High-Temperature Superconductor Fault Current Limiters

    Energy Technology Data Exchange (ETDEWEB)

    Darmann, Frank [Zenergy Power, Inc., Burlingame, CA (United States); Lombaerde, Robert [Zenergy Power, Inc., Burlingame, CA (United States); Moriconi, Franco [Zenergy Power, Inc., Burlingame, CA (United States); Nelson, Albert [Zenergy Power, Inc., Burlingame, CA (United States)

    2012-03-01

    Zenergy Power has successfully designed, built, tested, and installed in the US electrical grid a saturable reactor Fault Current Limiter. Beginning in 2007, first as SC Power Systems and from 2008 as Zenergy Power, Inc., ZP used DOE matching grant and ARRA funds to help refine the design of the saturated reactor fault current limiter. ZP ultimately perfected the design of the saturated reactor FCL to the point that ZP could reliably design a suitable FCL for most utility applications. Beginning with a very basic FCL design using 1G HTS for a coil housed in a LN2 cryostat for the DC bias magnet, the technology progressed to a commercial system that was offered for sale internationally. Substantial progress was made in two areas. First, the cryogenics cooling system progressed from a sub-cooled liquid nitrogen container housing the HTS coils to cryostats utilizing dry conduction cooling and reaching temperatures down to less than 20 degrees K. Large, round cryostats with warm bore diameters of 1.7 meters enabled the design of large tanks to hold the AC components. Second, the design of the AC part of the FCL was refined from a six legged spider design to a more compact and lighter design with better fault current limiting capability. Further refinement of the flux path and core shape led to an efficient saturated reactor design requiring less Ampere-turns to saturate the core. In conclusion, the development of the saturable reactor FCL led to a more efficient design not requiring HTS magnets and their associated peripheral equipment, which yielded a more economical product in line with the electric utility industry expectations. The original goal for the DOE funding of the ZP project Design, Test and Demonstration of Saturable Reactor High-Temperature Superconductor Fault Current Limiters was to stimulate the HTS wire industry with, first 1G, then 2G, HTS wire applications. Over the approximately 5 years of ZP's product development program, the amount of HTS

  13. Water Dissociation Phenomena on a Bipolar Membrane——Current-voltage Curve in Relation with Ionic Transport and Limiting Current Density

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The water dissociation mechanism on a bipolar membrane under the electrical field was investigated and characterized in terms of ionic transport and limiting current density. It is considered that the depletion layer exists at the junction of a bipolar membrane, which is coincided with the viewpoint of the most literatures, but we also consider that the thickness and conductivity of this layer is not only related with the increase of the applied voltage but also with the limiting current density. Below the limiting current density, the thickness of the depletion layer keeps a constant and the conductivity decreases with the increase of the applied voltage;while above the limiting current density, the depletion thickness will increase with the increase of the applied voltage and the conductivity keeps a very low constant. Based on the data reported in the literatures and independent determinations, the limiting current density was calculated and the experimental curves Ⅰ- Ⅴ in the two directions were compared with the theoretical calculations. It is demonstrated that above the limiting current density, the experimental results,either in the L-H direction or in the H-L direction, are consistent with the theoretical calculations; below the limiting current density, a slight deviation exists between the experimental and the theoretical results, and between the experimental results in the two directions. The change in Donnan potential due to the asymmetry of the mono-layers and the changes of ionic composition in the two directions is possibly responsible for this deviation.

  14. Bringing biofuels on the market. Options to increase EU biofuels volumes beyond the current blending limits

    Energy Technology Data Exchange (ETDEWEB)

    Kampman, B.; Van Grinsven, A.; Croezen, H. [CE Delft, Delft (Netherlands); Verbeek, R.; Van Mensch, P.; Patuleia, A. [TNO, Delft, (Netherlands)

    2013-07-15

    This handbook on biofuels provides a comprehensive overview of different types of biofuels, and the technical options that exist to market the biofuels volumes expected to be consumed in the EU Member States in 2020. The study concludes that by fully utilizing the current blending limits of biodiesel (FAME) in diesel (B7) and bioethanol in petrol (E10) up to 7.9% share of biofuels in the EU transport sector can be technically reached by 2020. Increasing use of advanced biofuels, particularly blending of fungible fuels into diesel (eg. HVO and BTL) and the use of higher ethanol blends in compatible vehicles (e.g. E20), can play an important role. Also, the increased use of biomethane (in particular bio-CNG) and higher blends of biodiesel (FAME) can contribute. However, it is essential for both governments and industry to decide within 1 or 2 years on the way ahead and take necessary actions covering both, the fuels and the vehicles, to ensure their effective and timely implementation. Even though a range of technical options exist, many of these require considerable time and effort to implement and reach their potential. Large scale implementation of the options beyond current blending limits requires new, targeted policy measures, in many cases complemented by new fuel and vehicle standards, adaptation of engines and fuel distribution, etc. Marketing policies for these vehicles, fuels and blends are also likely to become much more important than in the current situation. Each Member State may develop its own strategy tailored to its market and policy objectives, but the EU should play a crucial facilitating role in these developments.

  15. Progress in American Superconductor's HTS wire and optimization for fault current limiting systems

    Science.gov (United States)

    Malozemoff, Alexis P.

    2016-11-01

    American Superconductor has developed composite coated conductor tape-shaped wires using high temperature superconductor (HTS) on a flexible substrate with laminated metal stabilizer. Such wires enable many applications, each requiring specific optimization. For example, coils for HTS rotating machinery require increased current density J at 25-50 K. A collaboration with Argonne, Brookhaven and Los Alamos National Laboratories and several universities has increased J using an optimized combination of precipitates and ion irradiation defects in the HTS. Major commercial opportunities also exist to enhance electric power grid resiliency by linking substations with distribution-voltage HTS power cables [10]. Such links provide alternative power sources if one substation's transmission-voltage power is compromised. But they must also limit fault currents which would otherwise be increased by such distribution-level links. This can be done in an HTS cable, exploiting the superconductor-to-resistive transition when current exceeds the wires' critical J. A key insight is that such transitions are usually nonuniform; so the wire must be designed to prevent localized hot spots from damaging the wire or even generating gas bubbles in the cable causing dielectric breakdown. Analysis shows that local heating can be minimized by increasing the composite tape's total thickness, decreasing its total resistance in the normal state and decreasing its critical J. This conflicts with other desirable wire characteristics. Optimization of these conflicting requirements is discussed.

  16. Test Results For a 25-m Prototype Fault Current Limiting HTS Cable for Project Hydra

    Energy Technology Data Exchange (ETDEWEB)

    Rey, Christopher M [ORNL; Duckworth, Robert C [ORNL; Demko, Jonathan A [ORNL; Ellis, Alvin R [ORNL; Gouge, Michael J [ORNL; James, David Randy [ORNL; Tuncer, Enis [ORNL

    2010-01-01

    The Oak Ridge National Laboratory (ORNL) has tested a 25-m long prototype High Temperature Superconducting (HTS) cable with inherent Fault-Current Limiting (FCL) capability at its recently upgraded HTS cable test facility in Oak Ridge, TN. The HTS-FCL cable and terminations were designed and fabricated by Ultera, which is a joint venture of Southwire and nkt cables with FCL features and HTS wire provided by American Superconductor Corporation. The overall project is sponsored by the U.S. Department of Homeland Security. The ultimate goal of the 25-m HTS-FCL cable test program was to verify the design and ensure the operational integrity for the eventual installation of a ~ 200-m fully functional HTS-FCL cable in the Consolidated Edison electric grid located in downtown New York City. The 25-m HTS-FCL cable consisted of a three-phase (3- ) Triax design with a cold dielectric between the phases. The HTS-FCL cable had an operational voltage of 13.8 kV phase-to-phase and an operating current of 4000 Arms per phase, which is the highest operating current to date of any HTS cable. The 25-m HTS-FCL cable was subjected to a series of cryogenic and electrical tests. Test results from the 25-m HTS-FCL cable are presented and discussed.

  17. Development and Testing of a Transmission Voltage SuperLimiter™ Fault Current Limiter

    Energy Technology Data Exchange (ETDEWEB)

    Romanosky, Walter [American Superconductor Corporation, Devens, MA (United States)

    2012-09-01

    This report summarizes work by American Superconductor (AMSC), Los Alamos National Laboratory (LANL), Nexans, Siemens and Southern California Edison on a 138kV resistive type high temperature superconductor (HTS) fault current limiter (FCL) under a cooperative agreement with the U.S. Department of Energy (DOE). Phase 1A encompassed core technology development and system design and was previously reported (see summary that follows in Section 1.1 of the Introduction). This report primarily discusses work performed during Phase 1B, and addresses the fabrication and test of a single-phase prototype FCL. The results are presented along with a discussion of requirements/specifications and lessons learned to aid future development and product commercialization.

  18. Current limit diagrams for dendrite formation in solid-state electrolytes for Li-ion batteries

    Science.gov (United States)

    Raj, R.; Wolfenstine, J.

    2017-03-01

    We build upon the concept that nucleation of lithium dendrites at the lithium anode-solid state electrolyte interface is instigated by the higher resistance of grain boundaries that raises the local electro-chemical potential of lithium, near the lithium-electrode. This excess electro-chemo-mechanical potential, however, is reduced by the mechanical back stress generated when the dendrite is formed within the electrolyte. These parameters are coalesced into an analytical model that prescribes a specific criterion for dendrite formation. The results are presented in the form of current limit diagrams that show the "safe" and "fail" regimes for battery function. A higher conductivity of the electrolyte can reduce dendrite formation.

  19. Growth instability due to lattice-induced topological currents in limited-mobility epitaxial growth models.

    Science.gov (United States)

    Kanjanaput, Wittawat; Limkumnerd, Surachate; Chatraphorn, Patcha

    2010-10-01

    The energetically driven Ehrlich-Schwoebel barrier had been generally accepted as the primary cause of the growth instability in the form of quasiregular moundlike structures observed on the surface of thin film grown via molecular-beam epitaxy (MBE) technique. Recently the second mechanism of mound formation was proposed in terms of a topologically induced flux of particles originating from the line tension of the step edges which form the contour lines around a mound. Through large-scale simulations of MBE growth on a variety of crystalline lattice planes using limited-mobility, solid-on-solid models introduced by Wolf-Villain and Das Sarma-Tamborenea in 2+1 dimensions, we show that there exists a topological uphill particle current with strong dependence on specific lattice crystalline structure. Without any energetically induced barriers, our simulations produce spectacular mounds very similar, in some cases, to what have been observed in many recent MBE experiments. On a lattice where these currents cease to exist, the surface appears to be scale invariant, statistically rough as predicted by the conventional continuum growth equation.

  20. On the increase in the limiting current of an atmospheric-pressure glow discharge in an argon flow

    Science.gov (United States)

    Baldanov, B. B.; Ranzhurov, Ts. V.

    2014-04-01

    The initiation of an atmospheric-pressure glow discharge (APGD) is studied in the multitip cathode-planar anode electrode system through which an argon flow passes. It is shown that sectioning of the cathode and ballast resistances present at corona tips make it possible to substantially expand the current region of the discharge and considerably raise the limiting current of the APGD. The shape of the coronafree electrode is found to influence the limiting discharge current.

  1. Assessment on the influence of resistive superconducting fault current limiter in VSC-HVDC system

    Science.gov (United States)

    Lee, Jong-Geon; Khan, Umer Amir; Hwang, Jae-Sang; Seong, Jae-Kyu; Shin, Woo-Ju; Park, Byung-Bae; Lee, Bang-Wook

    2014-09-01

    Due to fewer risk of commutation failures, harmonic occurrences and reactive power consumptions, Voltage Source Converter (VSC) based HVDC system is known as the optimum solution of HVDC power system for the future power grid. However, the absence of suitable fault protection devices for HVDC system hinders the efficient VSC-HVDC power grid design. In order to enhance the reliability of the VSC-HVDC power grid against the fault current problems, the application of resistive Superconducting Fault Current Limiters (SFCLs) could be considered. Also, SFCLs could be applied to the VSC-HVDC system with integrated AC Power Systems in order to enhance the transient response and the robustness of the system. In this paper, in order to evaluate the role of SFCLs in VSC-HVDC systems and to determine the suitable position of SFCLs in VSC-HVDC power systems integrated with AC power System, a simulation model based on Korea Jeju-Haenam HVDC power system was designed in Matlab Simulink/SimPowerSystems. This designed model was composed of VSC-HVDC system connected with an AC microgrid. Utilizing the designed VSC-HVDC systems, the feasible locations of resistive SFCLs were evaluated when DC line-to-line, DC line-to-ground and three phase AC faults were occurred. Consequently, it was found that the simulation model was effective to evaluate the positive effects of resistive SFCLs for the effective suppression of fault currents in VSC-HVDC systems as well as in integrated AC Systems. Finally, the optimum locations of SFCLs in VSC-HVDC transmission systems were suggested based on the simulation results.

  2. Assessment on the influence of resistive superconducting fault current limiter in VSC-HVDC system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong-Geon; Khan, Umer Amir; Hwang, Jae-Sang; Seong, Jae-Kyu; Shin, Woo-Ju; Park, Byung-Bae; Lee, Bang-Wook, E-mail: bangwook@hanyang.ac.kr

    2014-09-15

    Highlights: • The role of SFCLs in VSC-HVDC systems was evaluated. • Simulation model based on Korea Jeju-Haenam HVDC power system was designed. • An effect and the feasible locations of resistive SFCLs were evaluated. • DC line-to-line, DC line-to-ground and 3 phase AC faults were imposed and analyzed. - Abstract: Due to fewer risk of commutation failures, harmonic occurrences and reactive power consumptions, Voltage Source Converter (VSC) based HVDC system is known as the optimum solution of HVDC power system for the future power grid. However, the absence of suitable fault protection devices for HVDC system hinders the efficient VSC-HVDC power grid design. In order to enhance the reliability of the VSC-HVDC power grid against the fault current problems, the application of resistive Superconducting Fault Current Limiters (SFCLs) could be considered. Also, SFCLs could be applied to the VSC-HVDC system with integrated AC Power Systems in order to enhance the transient response and the robustness of the system. In this paper, in order to evaluate the role of SFCLs in VSC-HVDC systems and to determine the suitable position of SFCLs in VSC-HVDC power systems integrated with AC power System, a simulation model based on Korea Jeju-Haenam HVDC power system was designed in Matlab Simulink/SimPowerSystems. This designed model was composed of VSC-HVDC system connected with an AC microgrid. Utilizing the designed VSC-HVDC systems, the feasible locations of resistive SFCLs were evaluated when DC line-to-line, DC line-to-ground and three phase AC faults were occurred. Consequently, it was found that the simulation model was effective to evaluate the positive effects of resistive SFCLs for the effective suppression of fault currents in VSC-HVDC systems as well as in integrated AC Systems. Finally, the optimum locations of SFCLs in VSC-HVDC transmission systems were suggested based on the simulation results.

  3. Dual Purpose Simulation: New Data Link Test and Performance Limit Testing of Currently Deployed Data Link

    Science.gov (United States)

    Robinson, Daryl C.

    2002-01-01

    While the results of this paper are similar to those of [I], in this paper technical difficulties present in [I] are eliminated, producing better results, enabling one to more readily see the benefits of Prioritized CSMA (PCSMA). A new analysis section also helps to generalize this research so that it is not limited to exploration of the new concept of PCSMA. Commercially available network simulation software, OPNET version 7.0, simulations are presented involving an important application of the Aeronautical Telecommunications Network (ATN), Controller Pilot Data Link Communications (CPDLC) over the Very High Frequency Data Link Mode 2 (VDL-2). Communication is modeled for essentially all incoming and outgoing nonstop air-traffic for just three United States cities: Cleveland, Cincinnati, and Detroit. The simulation involves 111 Air Traffic Control (ATC) ground stations, 32 airports distributed throughout the U.S., which are either sources or destinations for the air traffic landing or departing from the three cities, and also 1,235 equally equipped aircraft-taking off, flying realistic free-flight trajectories, and landing in a 24-hr period. Collision-less PCSMA is successfully tested and compared with the traditional CSMA typically associated with VDL-2. The performance measures include latency, throughput, and packet loss. As expected, PCSMA is much quicker and more efficient than traditional CSMA. These simulation results show the potency of PCSMA for implementing low latency, high throughput and efficient connectivity. Moreover, since PCSMA outperforms traditional CSMA, by simulating with it, we can determine the limits of performance beyond which traditional CSMA may not pass. So we have the tools to determine the traffic-loading conditions where traditional CSMA will fail, and we are testing a new and better data link that could replace it with relative ease. Work is currently being done to drastically expand the number of flights to make the simulation more

  4. Current Limitations in the Control and Spread of Ticks that Affect Livestock: A Review

    Directory of Open Access Journals (Sweden)

    Agustín Estrada-Peña

    2013-04-01

    Full Text Available Ticks are well-known parasites that affect livestock productivity. This paper reviews the current knowledge regarding the spread of ticks with their impact in animal health and the limitations to achieve effective control measures. The forecasted trends in climate play an obvious role in promoting the spread of ticks in several regions. It appears that climate warming is pivotal in the spread and colonization of new territories by Rhipicephalus microplus in several regions of Africa. The reported increase in altitude of this tick species in the mountainous regions of Central and South America appears to be driven by such general trends in climate change. This factor, however, is not the only single contributor to the spread of ticks. The poor management of farms, uncontrolled movements of domestic animals, abundance of wild animals, and absence of an adequate framework to capture the ecological plasticity of certain ticks may explain the complexity of the control measures. In this paper, we review several details regarding the relationships of ticks with the environment, wild fauna and competition with other species of ticks. Our intention is to highlight these relationships with the aim to produce a coherent framework to explore tick ecology and its relationship with animal production systems.

  5. Clinical Uses of Botulinum Neurotoxins: Current Indications, Limitations and Future Developments

    Directory of Open Access Journals (Sweden)

    Sheng Chen

    2012-10-01

    Full Text Available Botulinum neurotoxins (BoNTs cause flaccid paralysis by interfering with vesicle fusion and neurotransmitter release in the neuronal cells. BoNTs are the most widely used therapeutic proteins. BoNT/A was approved by the U.S. FDA to treat strabismus, blepharospam, and hemificial spasm as early as 1989 and then for treatment of cervical dystonia, glabellar facial lines, axillary hyperhidrosis, chronic migraine and for cosmetic use. Due to its high efficacy, longevity of action and satisfactory safety profile, it has been used empirically in a variety of ophthalmological, gastrointestinal, urological, orthopedic, dermatological, secretory, and painful disorders. Currently available BoNT therapies are limited to neuronal indications with the requirement of periodic injections resulting in immune-resistance for some indications. Recent understanding of the structure-function relationship of BoNTs prompted the engineering of novel BoNTs to extend therapeutic interventions in non-neuronal systems and to overcome the immune-resistance issue. Much research still needs to be done to improve and extend the medical uses of BoNTs.

  6. Possibilities and limitations of current technologies for quantification of biological extracellular vesicles and synthetic mimics

    Science.gov (United States)

    Maas, Sybren L.N.; de Vrij, Jeroen; van der Vlist, Els J.; Geragousian, Biaina; van Bloois, Louis; Mastrobattista, Enrico; Schiffelers, Raymond M.; Wauben, Marca H.M.; Broekman, Marike L.D.; Nolte-'t Hoen, Esther N.M.

    2015-01-01

    Nano-sized extracelullar vesicles (EVs) released by various cell types play important roles in a plethora of (patho)physiological processes and are increasingly recognized as biomarkers for disease. In addition, engineered EV and EV-inspired liposomes hold great potential as drug delivery systems. Major technologies developed for high-throughput analysis of individual EV include nanoparticle tracking analysis (NTA), tunable resistive pulse sensing (tRPS) and high-resolution flow cytometry (hFC). Currently, there is a need for comparative studies on the available technologies to improve standardization of vesicle analysis in diagnostic or therapeutic settings. We investigated the possibilities, limitations and comparability of NTA, tRPS and hFC for analysis of tumor cell-derived EVs and synthetic mimics (i.e. differently sized liposomes). NTA and tRPS instrument settings were identified that significantly affected the quantification of these particles. Furthermore, we detailed the differences in absolute quantification of EVs and liposomes using the three technologies. This study increases our understanding of possibilities and pitfalls of NTA, tRPS and hFC, which will benefit standardized and large-scale clinical application of (engineered) EVs and EV-mimics in the future. PMID:25555362

  7. Combining Pharmacological and Psychological Treatments for Binge Eating Disorder: Current Status, Limitations, and Future Directions.

    Science.gov (United States)

    Grilo, Carlos M; Reas, Deborah L; Mitchell, James E

    2016-06-01

    Binge eating disorder (BED) is characterized by recurrent binge eating and marked distress about binge eating without the extreme compensatory behaviors for weight control that characterize other eating disorders. BED is prevalent, associated strongly with obesity, and is associated with heightened levels of psychological, psychiatric, and medical concerns. This article provides an overview of randomized controlled treatments for combined psychological and pharmacological treatment of BED to inform current clinical practice and future treatment research. In contrast to the prevalence and significance of BED, to date, limited research has been performed on combining psychological and pharmacological treatments for BED to enhance outcomes. Our review here found that combining certain medications with cognitive behavioral therapy (CBT) or behavioral weight loss (BWL) interventions produces superior outcomes to pharmacotherapy only but does not substantially improve outcomes achieved with CBT/BWL only. One medication (orlistat) has improved weight losses with CBT/BWL albeit minimally, and only one medication (topiramate) has enhanced reductions achieved with CBT in both binge eating and weight. Implications for future research are discussed.

  8. Investigation on the Arc Ignition Characteristics and Energy Absorption of Liquid Metal Current Limiter Based on Self-Pinch Effect

    Institute of Scientific and Technical Information of China (English)

    JU Xingbao; SUN Haishun; YANG Zhuo; ZHANG Junmin

    2016-01-01

    The GaInSn liquid metal current limiter based on the fluid pinch effect has broad application prospects due to its particular properties.However,the limited rated current and ability of power dissipation are the critical problems for its wide application.Firstly,the temperature distribution of the liquid metal current limiter (LMCL) was obtained by experiments with a rated current of 1 kA and the arc ignition phenomenon was observed with 1.5 kA,which indicates that the rated current is mainly limited by the arc rather than the high temperature compared to the traditional switchgears.Furthermore,an improved method is proposed by adding the paralleled pure resistance,impedance or another LMCL element to protect the setup from the fault energy concentration in the setup.The problem of a slower arc voltage increasing rate can be solved by adding a paralleled impedance with suitable parameters.Finally,the current limiting properties based on the improved method were investigated and the alternating oscillating current was found between two paralleled LMCL elements owing to their deviation of arc ignition in reality.

  9. Scanning fast and slow: current limitations of 3 Tesla functional MRI and future potential

    Directory of Open Access Journals (Sweden)

    Roland N Boubela

    2014-02-01

    Full Text Available Functional MRI at 3T has become a workhorse for the neurosciences, e.g., neurology, psychology, and psychiatry, enabling non-invasive investigation of brain function and connectivity. However, BOLD-based fMRI is a rather indirect measure of brain function, confounded by fluctuation related signals, e.g. head or brain motion, brain pulsation, blood flow, intermixed with susceptibility differences close or distant to the region of neuronal activity. Even though a plethora of preprocessing strategies have been published to address these confounds, their efficiency is still under discussion. In particular, physiological signal fluctuations closely related to brain supply may mask BOLD signal changes related to true neuronal activation. Here we explore recent technical and methodological advancements aimed at disentangling the various components, employing fast multiband vs. standard EPI, in combination with fast temporal ICA.Our preliminary results indicate that fast (TR< 0.5s scanning may help to identify and eliminate physiologic components, increasing tSNR and functional contrast. In addition, biological variability can be studied and task performance better correlated to other measures. This should increase specificity and reliability in fMRI studies. Furthermore, physiological signal changes during scanning may then be recognized as a source of information rather than a nuisance. As we are currently still undersampling the complexity of the brain, even at a rather coarse macroscopic level, we should be very cautious in the interpretation of neuroscientific findings, in particular when comparing different groups (e.g., age, sex, medication, pathology, etc.. From a technical point of view our goal should be to sample brain activity at layer specific resolution with low TR, covering as much of the brain as possible without violating SAR limits. We hope to stimulate discussion towards a better understanding and a more quantitative use of fMRI.

  10. New lightning current resistant low voltage limiting device for DC railway systems; Neue blitzstromtragfaehige Niederspannungsbegrenzungseinrichtung zum Potenzialschutz von Gleichstrombahnsystemen

    Energy Technology Data Exchange (ETDEWEB)

    Rocks, A.; Hinrichsen, V. [Technische Univ. Darmstadt (Germany). Fachgebiet Hochspannungstechnik; Richter, B. [ABB Schweiz AG, Wettingen (Switzerland); Zayer, H. [ESN Bahngeraete GmbH, Mannheim (Germany)

    2007-07-01

    In dc railway systems, low voltage limiters are applied to limit potential rises in case of failures by forming a permanent short-circuit between return circuit and Earth. These devices can usually carry only moderate lightning currents without permanent failure. In this contribution, a new concept is introduced which provides personal as well as equipment protection by combining a surge arrester and a low voltage limiter in a suited way. (orig.)

  11. Fault Ride Though Control of Photovoltaic Grid-connected Inverter with Current-limited Capability under Offshore Unbalanced Voltage Conditions

    DEFF Research Database (Denmark)

    Liu, Wenzhao; Guo, Xiaoqiang; Savaghebi, Mehdi;

    2016-01-01

    of the excessive current phenomenon with the conventional fault ride through control is discussed. The quantitative analysis of the current peak value is conducted and a new current-limiting control strategy is proposed to achieve the flexible power control and successful fault ride through in a safe current......The photovoltaic (PV) inverter installed on board experiences the excessive current stress in case of the offshore unbalanced voltage fault ride through (FRT), which significantly affects the operation reliability of the power supply system. In order to solve the problem, the inherent mechanism...

  12. Formation of a spark discharge in an inhomogeneous electric field with current limitation by a large ballast Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Baldanov, B. B., E-mail: baibat@mail.ru [Russian Academy of Sciences, Institute of Physical Material Science, Siberian Branch (Russian Federation)

    2016-01-15

    Results of studies of a spark discharge initiated in argon in a point–plane electrode gap with limitation of the discharge current by a large ballast resistance are presented. It is shown that the current flowing through the plasma channel of such a low-current spark has the form of periodic pulses. It is experimentally demonstrated that, when a low-current spark transforms into a constricted glow discharge, current pulses disappear, the spatial structure of the cathode glow changes abruptly, and a brightly glowing positive plasma column forms in the gap.

  13. Flexible Power Regulation and Current-limited Control of Grid-connected Inverter under Unbalanced Grid Voltage Faults

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Liu, Wenzhao; Lu, Zhigang

    2017-01-01

    The grid-connected inverters may experience excessive current stress in case of unbalanced grid voltage Fault Ride Through (FRT), which significantly affects the reliability of the power supply system. In order to solve the problem, the inherent mechanisms of the excessive current phenomenon...... with the conventional FRT solutions are discussed. The quantitative analysis of three phase current peak values are conducted and a novel current-limited control strategy is proposed to achieve the flexible active and reactive power regulation and successful FRT in a safe current operation area with the aim...

  14. Influence of current limitation on voltage stability with voltage sourced converter HVDC

    DEFF Research Database (Denmark)

    Zeni, Lorenzo; Jóhannsson, Hjörtur; Hansen, Anca Daniela;

    2013-01-01

    A first study of voltage stability with relevant amount of Voltage Sourced Converter based High Voltage Direct Current (VSC-HVDC) transmission is presented, with particular focus on the converters’ behaviour when reaching their rated current. The detrimental effect of entering the current...

  15. Proceedings of the 1979 workshop on beam current limitations in storage rings, July 16-27, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrini, C. (ed.)

    1979-01-01

    The Workshop on Beam Current Limitations in Storage Rings was held at Brookhaven National Laboratory from July 16 to 27, 1979. The purpose of this Workshop was to discuss the physical mechanisms limiting the beam current or current density in accelerators or storage rings. Many of these machines are now being built or planned for a variety of applications, such as colliding beam experiments, synchrotron light production, heavy ion beams. This diversity was reflected in the Workshop and in the papers which have been contributed to these Proceedings. The twenty-one papers from the workshop were incorporated individually in the data base. (GHT)

  16. Characterization of superconducting coil for fault current limitation; Caracterizacao de bobina supercondutora para limitacao de corrente de curto-circuito

    Energy Technology Data Exchange (ETDEWEB)

    Polasek, Alexander; Dias, Rodrigo; Niedu, Daniel Brito; Ogasawara, Tsuneharu; Oliveira Filho, Orsino Borges de; Serra, Eduardo Torres [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil); Gomes Junior, George; Amorim, Helio Salim [Coordenacao dos Programas de Pos-Graduacao em Engeharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil)

    2010-07-01

    The increasing power demand has been raising fault currents up to dangerous levels. Superconducting fault current limiters are a promising solution for this problem. In the present work, we studied a superconducting Bi-2212 coil that is used for fault current limitation. Samples were analyzed by XRD, SEM/EDS and measurement of critical temperature (Tc). The Rietveld method was employed for phase quantification. Relatively high Bi-2212 fractions were found. However, Tc varies from a sample to another one. Variations of local Tc are attributed to variations of oxygen content in Bi- 2212 phase. (author)

  17. Space-charge-limited leakage current in high dielectric constant and ferroelectric thin films considering the field-dependent permittivity

    Science.gov (United States)

    Sun, J.; Zheng, X. J.; Yin, W.; Tang, M. H.; Li, W.

    2010-12-01

    Distinguishing from the traditional characterization on high-field leakage current density-voltage relationship, the field-dependent permittivity from the polarization derivative is used to solve the space-charge-limited conduction, and the simulated leakage current densities are compared with the previous experimental observations. The influences of the mobility, ferroelectric parameters, and film thickness on the leakage current densities are discussed. The results verify that the high-field quasi-Ohmic region observed experimentally may result from the field-dependent permittivity, and that the leakage current can be influenced by the ferroelectric polarization.

  18. Design and optimization of LCL-VSC grid-tied converter having short circuit fault current limiting ability

    Science.gov (United States)

    Liu, Mengqi; Liu, Haijun; Wang, Zhikai

    2017-01-01

    Traditional LCL grid-tied converters haven't the ability to limit the short-circuit fault current and only remove grid-connected converter using the breaker. However, the VSC converters become uncontrollable after the short circuit fault cutting off and the power switches may be damaged if the circuit breaker removes slowly. Compared to the filter function of the LCL passive components in traditional VSC converters, the novel LCL-VSC converter has the ability of limiting the short circuit fault current using the reasonable designed LCL parameters. In this paper the mathematical model of the LCL converter is established and the characteristics of the short circuit fault current generated by the ac side and dc side are analyzed. Thus one design and optimization scheme of the reasonable LCL passive parameter is proposed for the LCL-VSC converter having short circuit fault current limiting ability. In addition to ensuring the LCL passive components filtering the high-frequency harmonic, this scheme also considers the impedance characteristics to limit the fault current of AC and DC short circuit fault respectively flowing through the power switch no more than the maximum allowable operating current, in order to make the LCL converter working continuously. Finally, the 200kW simulation system is set up to prove the validity and feasibility of the theoretical analysis using the proposed design and optimization scheme.

  19. The Effect of Current-Limiting Reactors on the Tripping of Short Circuits in High-Voltage Electrical Equipment

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, M. S.; Gusev, Yu. P., E-mail: GusevYP@mpei.ru; Monakov, Yu. V.; Cho, Gvan Chun [National Research University “Moscow Power Engineering Institute,” (Russian Federation)

    2016-01-15

    The insertion of current-limiting reactors into electrical equipment operating at a voltage of 110 and 220 kV produces a change in the parameters of the transient recovery voltages at the contacts of the circuit breakers for disconnecting short circuits, which could be the reason for the increase in the duration of the short circuit, damage to the electrical equipment and losses in the power system. The results of mathematical modeling of the transients, caused by tripping of the short circuit in a reactive electric power transmission line are presented, and data are given on the negative effect of a current-limiting resistor on the rate of increase and peak value of the transient recovery voltages. Methods of ensuring the standard requirements imposed on the parameters of the transient recovery voltages when using current-limiting reactors in the high-voltage electrical equipment of power plants and substations are proposed and analyzed.

  20. Voltage Quality Enhancement and Fault Current Limiting with Z-Source based Series Active Filter

    Directory of Open Access Journals (Sweden)

    F. Gharedaghi

    2011-11-01

    Full Text Available In this study, series active filter or dynamic voltage restorer application is proposed for reduction of downstream fault current in addition to voltage quality enhancement. Recently, the application of Z-source inverter is proposed in order to optimize DVR operation. This inverter makes DVR to operate appropriately when the energy storage device’s voltage level severely falls. Here, the Z-source inverter based DVR is proposed to compensate voltage disturbance at the PCC and to reduce the fault current in downstream of DVR. By calculating instantaneous current magnitude in synchronous frame, control system recognizes if the fault exists or not, and determines whether DVR should compensate voltage disturbance or try to reduce the fault current. The proposed system is simulated under voltage sag and swell and short circuit conditions. The simulation results show that the system operates correctly under voltage sag and short circuit conditions.

  1. Status and Progress of a Fault Current Limiting Hts Cable to BE Installed in the con EDISON Grid

    Science.gov (United States)

    Maguire, J.; Folts, D.; Yuan, J.; Henderson, N.; Lindsay, D.; Knoll, D.; Rey, C.; Duckworth, R.; Gouge, M.; Wolff, Z.; Kurtz, S.

    2010-04-01

    In the last decade, significant advances in the performance of second generation (2G) high temperature superconducting wire have made it suitable for commercially viable applications such as electric power cables and fault current limiters. Currently, the U.S. Department of Homeland Security is co-funding the design, development and demonstration of an inherently fault current limiting HTS cable under the Hydra project with American Superconductor and Consolidated Edison. The cable will be approximately 300 m long and is being designed to carry 96 MVA at a distribution level voltage of 13.8 kV. The underground cable will be installed and energized in New York City. The project is led by American Superconductor teamed with Con Edison, Ultera (Southwire and nkt cables joint venture), and Air Liquide. This paper describes the general goals, design criteria, status and progress of the project. Fault current limiting has already been demonstrated in 3 m prototype cables, and test results on a 25 m three-phase cable will be presented. An overview of the concept of a fault current limiting cable and the system advantages of this unique type of cable will be described.

  2. A Versatile Control Scheme For Dynamic Voltage Restorer To Limit Downstream Fault Currents

    Directory of Open Access Journals (Sweden)

    A.Nagendra

    2014-12-01

    Full Text Available The Dynamic Voltage Restorer (DVR is a custom power device utilized to counteract voltage sags. It injects controlled three-phase ac voltages in series with the supply voltage, subsequent to voltage sag, to enhance voltage quality by adjusting the voltage magnitude, wave shape, and phase angle. The DVR is conventionally bypassed during a downstream fault to prevent potential adverse impacts on the fault and to protect the DVR components against the fault current. This paper proposes an augmented control strategy for the DVR that provides:1 voltage-sag compensation under balanced and unbalanced conditions and 2 a fault current interruption (FCI function. This paper introduces and evaluates an auxiliary control strategy for downstream fault current interruption in a radial distribution line by means of a dynamic voltage restorer (DVR. The proposed controller supplements the voltage-sag compensation control of the DVR. It does not require phaselocked loop and independently controls the magnitude and phase angle of the injected voltage for each phase. Fast least error squares digital filters are used to estimate the magnitude and phase of the measured voltages and effectively reduce the impacts of noise, harmonics, and disturbances on the estimated phasor parameters, and this enables effective fault current interrupting even under arcing fault conditions. The performance of the DVR for fault current interruption is analyzed by using MATLAB/SIMULINK software.

  3. Estimation of the spatial distribution of traps using space-charge-limited current measurements in an organic single crystal

    KAUST Repository

    Dacuña, Javier

    2012-09-06

    We used a mobility edge transport model and solved the drift-diffusion equation to characterize the space-charge-limited current of a rubrene single-crystal hole-only diode. The current-voltage characteristics suggest that current is injection-limited at high voltage when holes are injected from the bottom contact (reverse bias). In contrast, the low-voltage regime shows that the current is higher when holes are injected from the bottom contact as compared to hole injection from the top contact (forward bias), which does not exhibit injection-limited current in the measured voltage range. This behavior is attributed to an asymmetric distribution of trap states in the semiconductor, specifically, a distribution of traps located near the top contact. Accounting for a localized trap distribution near the contact allows us to reproduce the temperature-dependent current-voltage characteristics in forward and reverse bias simultaneously, i.e., with a single set of model parameters. We estimated that the local trap distribution contains 1.19×1011 cm -2 states and decays as exp(-x/32.3nm) away from the semiconductor-contact interface. The local trap distribution near one contact mainly affects injection from the same contact, hence breaking the symmetry in the charge transport. The model also provides information of the band mobility, energy barrier at the contacts, and bulk trap distribution with their corresponding confidence intervals. © 2012 American Physical Society.

  4. High or low-side solid state relay with current limiting and operational testing

    Science.gov (United States)

    Dolland, C. R.

    1984-07-01

    The switch comprises a circuit from a first output terminal via parallel MOS devices in series with current-sensing resistance to a second output terminal, with alternative high-side and low-side configurations having a load between the second terminal and ground, or the first terminal and the DC supply voltage. An input terminal for a digital control signal is coupled via an input diode and two Schmitt Trigger CMOS inverters to a control lead for the gates of the switch. A current overload or short circuit protection circuit coupled between the current-sensor and the input diode comprises two transistors coupled by a diode. A built-in test circuit for indicating the switch condition (on, off, shorted or open) comprises MOS transistors having their gates connected to voltage dividers at the two output terminals, and their drains connected to discrete indication terminals.

  5. Thickness scaling of the space-charge-limited current in poly(p-phenylene vinylene)

    NARCIS (Netherlands)

    Blom, PWM; Tanase, C; de Leeuw, DM; Coehoorn, R

    2005-01-01

    Charge transport in light-emitting diodes (LEDs) based on a polyp-phenylene vinylene) (PPV) derivative is investigated as a function of sample thickness. Via the thickness dependence, the contributions from the electric field and charge carrier density to the mobility in space-charge-limited (SCL) d

  6. Active to sterile neutrino mixing limits from neutral-current interactions in MINOS

    CERN Document Server

    Adamson, P; Ayres, D S; Backhouse, C; Barr, G; Bishai, M; Blake, A; Bock, G J; Boehnlein, D J; Bogert, D; Cavanaugh, S; Cherdack, D; Childress, S; Coelho, J A B; Coleman, S J; Corwin, L; Cronin-Hennessy, D; Danko, I Z; de Jong, J K; Devenish, N E; Diwan, M V; Dorman, M; Escobar, C O; Evans, J J; Falk, E; Feldman, G J; Frohne, M V; Gallagher, H R; Gomes, R A; Goodman, M C; Gouffon, P; Graf, N; Gran, R; Grant, N; Grzelak, K; Habig, A; Harris, D; Hartnell, J; Hatcher, R; Himmel, A; Holin, A; Huang, X; Hylen, J; Ilic, J; Irwin, G M; Isvan, Z; Jaffe, D E; James, C; Jensen, D; Kafka, T; Kasahara, S M S; Koizumi, G; Kopp, S; Kordosky, M; Kreymer, A; Lang, K; Lefeuvre, G; Ling, J; Litchfield, P J; Loiacono, L; Lucas, P; Mann, W A; Marshak, M L; Mayer, N; McGowan, A M; Mehdiyev, R; Meier, J R; Messier, M D; Miller, W H; Mishra, S R; Mitchell, J; Moore, C D; Morfín, J; Mualem, L; Mufson, S; Musser, J; Naples, D; Nelson, J K; Newman, H B; Nichol, R J; Nicholls, T C; Nowak, J A; Oliver, W P; Orchanian, M; Paley, J; Patterson, R B; Pawloski, G; Pearce, G F; Petyt, D A; Phan-Budd, S; Pittam, R; Plunkett, R K; Qiu, X; Ratchford, J; Raufer, T M; Rebel, B; Rodrigues, P A; Rosenfeld, C; Sanchez, H A Rubin M C; Schneps, J; Schreiner, P; Sharma, R; Shanahan, P; Sousa, A; Stamoulis, P; Strait, M; Tagg, N; Talaga, R L; Tetteh-Lartey, E; Thomas, J; Thomson, M A; Tinti, G; Toner, R; Torretta, D; Tzanakos, G; Urheim, J; Vahle, P; Viren, B; Walding, J J; Weber, A; Webb, R C; White, C; Whitehead, L; Wojcicki, S G; Zwaska, R

    2011-01-01

    Results are reported from a search for active to sterile neutrino oscillations in the MINOS long-baseline experiment, based on the observation of neutral-current neutrino interactions, from an exposure to the NuMI neutrino beam of $7.07\\times10^{20}$ protons on target. A total of 802 neutral-current event candidates is observed in the Far Detector, compared to an expected number of $754\\pm28\\rm{(stat.)}\\pm{37}\\rm{(syst.)}$ for oscillations among three active flavors. The fraction $f_s$ of disappearing \

  7. Current strategies for improving access and adherence to antiretroviral therapies in resource-limited settings

    Directory of Open Access Journals (Sweden)

    Scanlon ML

    2013-01-01

    Full Text Available Michael L Scanlon,1,2 Rachel C Vreeman1,21Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA; 2USAID, Academic Model Providing Access to Healthcare (AMPATH Partnership, Eldoret, KenyaAbstract: The rollout of antiretroviral therapy (ART significantly reduced human immunodeficiency virus (HIV-related morbidity and mortality, but good clinical outcomes depend on access and adherence to treatment. In resource-limited settings, where over 90% of the world’s HIV-infected population resides, data on barriers to treatment are emerging that contribute to low rates of uptake in HIV testing, linkage to and retention in HIV care systems, and suboptimal adherence rates to therapy. A review of the literature reveals limited evidence to inform strategies to improve access and adherence with the majority of studies from sub-Saharan Africa. Data from observational studies and randomized controlled trials support home-based, mobile and antenatal care HIV testing, task-shifting from doctor-based to nurse-based and lower level provider care, and adherence support through education, counseling and mobile phone messaging services. Strategies with more limited evidence include targeted HIV testing for couples and family members of ART patients, decentralization of HIV care, including through home- and community-based ART programs, and adherence promotion through peer health workers, treatment supporters, and directly observed therapy. There is little evidence for improving access and adherence among vulnerable groups such as women, children and adolescents, and other high-risk populations and for addressing major barriers. Overall, studies are few in number and suffer from methodological issues. Recommendations for further research include health information technology, social-level factors like HIV stigma, and new research directions in cost-effectiveness, operations, and implementation. Findings from this review make a

  8. Rapid Detection Strategies for the Global Threat of Zika Virus: Current State, New Hypotheses and Limitations

    Directory of Open Access Journals (Sweden)

    Shruti Shukla

    2016-10-01

    Full Text Available The current scenario regarding the widespread Zika virus (ZIKV has resulted in numerous diagnostic studies, specifically in South America and in locations where there is frequent entry of travelers returning from ZIKV-affected areas, including pregnant women with or without clinical symptoms of ZIKV infection. The World Health Organization, WHO, announced that millions of cases of ZIKV are likely to occur in the United States of America in the near future. This situation has created an alarming public health emergency of international concern requiring the detection of this life-threatening viral candidate due to increased cases of newborn microcephaly associated with ZIKV infection. Hence, this review reports possible methods and strategies for the fast and reliable detection of ZIKV with particular emphasis on current updates, knowledge and new hypotheses that might be helpful for medical professionals in poor and developing countries that urgently need to address this problem. In particular, we emphasize liposome-based biosensors. Although these biosensors are currently among the less popular tools for human disease detection, they have become useful tools for the screening and detection of pathogenic bacteria, fungi and viruses because of their versatile advantageous features compared to other sensing devices. This review summarizes the currently available methods employed for the rapid detection of ZIKV and suggests an innovative approach involving the application of a liposome-based hypothesis for the development of new strategies for ZIKV detection and their use as effective biomedicinal tools.

  9. Space-charge-limited current and the effect of light in CdS-single crystals

    NARCIS (Netherlands)

    Driedonks, F.; Zijlstra, R.J.J.

    1966-01-01

    Thin CdS-single crystals in darkness show current-voltage characteristics in agreement with Lampert's theory. Illumination with photons in the extrinsic energy-range appears to increase considerably the amount of injected charge that remains free in the conduction band.

  10. Behaviour of bipolar membranes at high current density. Water diffusion limitation

    NARCIS (Netherlands)

    Krol, J.J.; Jansink, M.G.J.; Wessling, Matthias; Strathmann, H.

    1998-01-01

    In this paper the behaviour of bipolar membranes at very high current density is discussed. Current–voltage curves are determined, both for the Tokuyama Soda BP-1 and the WSI Technologies bipolar membrane. The current–voltage curves are characterised by an inflection point at which a drastic

  11. Current status data with competing risks: limiting distribution of the MLE

    NARCIS (Netherlands)

    Groeneboom, P.; Maathuis, M.H.; Wellner, J.A.

    2008-01-01

    We study nonparametric estimation for current status data with competing risks. Our main interest is in the nonparametric maximum likelihood estimator (MLE), and for comparison we also consider a simpler “naive estimator.” Groeneboom, Maathuis and Wellner [Ann. Statist. (2008) 36 1031–1063] proved t

  12. Prehospital Stroke Care : Limitations of Current Interventions and Focus on New Developments

    NARCIS (Netherlands)

    Yperzeele, Laetitia; Van Hooff, Robbert-Jan; De Smedt, Ann; Espinoza, Alexis Valenzuela; de Casseye, Rohny Van; Hubloue, Ives; De Keyser, Jacques; Brouns, Raf

    Background: The global burden of stroke is immense, both in medical and economic terms. With the aging population and the ongoing industrialization of the third world, stroke prevalence is expected to increase and will have a major effect on national health expenditures. Currently, the medical

  13. Noise in space-charge-limited current in a CdS-single crystal at low injection level

    NARCIS (Netherlands)

    Driedonks, F.

    1967-01-01

    Current noise spectra (25Hz–20MHz) of a CdS-diode, working under space-charge-limited conditions. show trapping noise at low frequencies and slightly suppressed noise in the upper frequency range. Suppression is relatively small due to the effect of traps.

  14. Current Density Limitations in a Fast-Pulsed High-Voltage Diode

    Science.gov (United States)

    1992-06-01

    based on mass x acceleration - charge x E-field) - - -= qT (x)=-e rT(X) (19) dt M c M c where y ,ŕ /•/ 2/c ••V/c; t * time (S) e I electron charge I... Plasmaphysik IPP 4/250, September 1991. 6. Parker, R.K., Explosive Electron Emission and the Characteristics of High-Current Electron Flow, Air Force

  15. [Outpatient thoracic surgery: Evolution of the indications, current applications and limits].

    Science.gov (United States)

    Bagan, P; Berna, P; De Dominicis, F; Lafitte, S; Zaimi, R; Dakhil, B; Das Neves Pereira, J-C

    2016-12-01

    The objectives of outpatient surgery are to reduce the risks connected to hospitalization, to improve postoperative recovery and to decrease the health costs. Few studies have been performed in the field of thoracic surgery and there remains great scope for progress in outpatient lung surgery. The purpose of this article is to present a revue of the current situation and the prospects for the development of out patient thoracic surgery.

  16. Measures to observe the current dust emission limit; Massnahmen zur Einhaltung des aktuellen Staubemissionsgrenzwerts

    Energy Technology Data Exchange (ETDEWEB)

    Evard, Michael [Vattenfall Europe Waerme AG, Berlin (Germany). Betrieb Heizkraftwerk Moabit

    2011-07-01

    The paper describes the operational experience and optimisation approach for a hot electrostatic precipitator (ESP) with a flue gas temperature of approximately 350 C as part of a circulating fluidised bed (CFB) boiler. It is particularly dealing with fault finding and cleaning after 20 years of operation. From the beginning of January 2011, new laws have come into force regulating dust emission limits. Therefore, it was necessary that existing ESP systems operate optimally. The ESP is a part of a hard coal-fired CFB boiler. (orig.)

  17. Stem cells for clinical use in cardiovascular medicine: current limitations and future perspectives.

    Science.gov (United States)

    Menasché, Philippe

    2005-10-01

    Cell transplantation is currently gaining a growing interest as a potential new means of improving the prognosis of patients with cardiac failure. The basic assumption is that left ventricular dysfunction is largely due to the loss of a critical number of cardiomyocytes and that it can be partly reversed by implantation of new contractile cells into the postinfarction scars. Primarily for practical reasons, autologous skeletal myoblasts have been the first to undergo clinical trials and now that the feasibility of the procedure is well established, efficacy data are expected from the ongoing randomized studies. Bone marrow stem cells are also generating a great deal of interest, particularly in patients with acute myocardial infarction, and are currently undergoing extensive clinical testing although recent data have raised a cautionary note about the transdifferentiation potential of these cells. While experimental studies and early-phase clinical trials tend to support the concept that cell therapy may enhance cardiac repair, several key issues still need to be addressed including (1) the optimal type of donor cells in relation to the clinical profile of the patients, (2) the mechanism by which cell engraftment improves cardiac function, (3) the optimization of cell survival, (4) the development of less invasive cell delivery techniques and (5) the potential benefits of cell transplantation in nonischemic heart failure. Current evidence suggests, however, that adult stem cells (myogenic or marrow-derived) fail to electromechanically integrate within the recipient heart, thereby mandating the search for second generation cell types able to achieve this goal which is the prerequisite for an effective enhancement of contractile function. Preliminary data suggest that cells that feature a true cardiomyogenic phenotype such as cardiac stem cells and cardiac-precommitted embryonic stem cells may fall in this category and carry the potential for ensuring a true

  18. The impact of antiretroviral therapy in resource-limited settings and current HIV therapeutics.

    Science.gov (United States)

    Kumarasamy, N

    2016-04-01

    Four million people of the global total of 35 million with HIV infection are from South-East Asia. ART is currently utilized by 15 million people and has led to a dramatic decline in the mortality rate, including those in low- and middle-income countries. A reduction in sexually transmitted HIV and in comorbidities including tuberculosis has also followed. Current recommendations for the initiation of antiretroviral therapy in people who are HIV+ are essentially to initiate ART irrespective of CD4 cell count and clinical stage. The frequency of HIV testing should be culturally specific and based on the HIV incidence in different key populations but phasing in viral load technology in LMIC is an urgent priority and this needs resources and capacity. With the availability of simplified potent ART regimens, persons with HIV now live longer. The recent WHO treatment guidelines recommending routine HIV testing and earlier initiation of treatment should be the stepping stone for ending the AIDS epidemic and to meet the UNAIDS mission of 90*90*90.

  19. Current Challenges and Limitations in Antibody-Based Detection of Citrullinated Histones

    Science.gov (United States)

    Neeli, Indira; Radic, Marko

    2016-01-01

    Studies on NETosis demand reliable and convenient markers to monitor the progress of this form of cell death. Because a determining step in the release of nuclear chromatin NETs requires the conversion of arginine residues to citrulline residues in histones by peptidylarginine deiminase, citrullinated histones can provide such a marker. Here, we evaluate antibody reagents for the detection of citrulline residues in histones and observe alarming differences between commercial antisera and mouse and rabbit monoclonal antibodies in their ability to detect their nominal target residues. Differences between antibodies that are currently used to detect citrulline residues in histones could jeopardize efforts to reach a scientific consensus and instead lead to inconsistent and even conflicting conclusions regarding the regulation of histone deimination. Our results will assist others in planning their initial or ongoing studies on peptidylarginine deiminase activity with the use of currently available antibodies. Furthermore, we argue that, along with the careful attention to experimental conditions and calcium concentrations, validated antibody reagents are urgently needed to avoid possible setbacks in the research on NETosis. PMID:27933065

  20. Current Challenges and Limitations in Antibody-Based Detection of Citrullinated Histones

    Directory of Open Access Journals (Sweden)

    Indira Neeli

    2016-11-01

    Full Text Available Studies on NETosis demand reliable and convenient markers to monitor the progress of this form of cell death. Because a determining step in the release of nuclear chromatin NETs requires the conversion of arginine residues to citrulline residues in histones by peptidylarginine deiminase, citrullinated histones can provide such a marker. Here, we evaluate antibody reagents for the detection of citrulline residues in histones and observe alarming differences between commercial antisera and mouse and rabbit monoclonal antibodies in their ability to detect their nominal target residues. Differences between antibodies that are currently used to detect citrulline residues in histones could jeopardize efforts to reach a scientific consensus and instead lead to inconsistent and even conflicting conclusions regarding the regulation of histone deimination. Our results will assist others in planning their initial or ongoing studies on peptidylarginine deiminase activity with the use of currently available antibodies. Further, we argue that, along with the careful attention to experimental conditions and calcium concentrations, validated antibody reagents are urgently needed to avoid possible setbacks in the research on NETosis.

  1. Visualization of the boiling phenomena and counter-current flow limit of annular heat pipe

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Guk; Kim, Kyung Mo; Jeong, Yeong Shin; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of)

    2015-10-15

    The thermal resistance of conventional heat pipes increases over the capillary limit because of the insufficient supplement of the working fluid. Due to the shortage of the liquid supplement, thermosyphon is widely used for vertically oriented heat transport and high heat load conditions. Thermosyphons are two-phase heat transfer devices that have the highly efficient heat transport from evaporation to condensation section that makes an upward driving force for vapor. In the condenser section, the vapor condenses and releases the latent heat. Due to the gravitation force acting on the liquid in the tube, working fluid back to the evaporator section, normally this process operate at the vertical and inclination position. The use of two-phase closed thermosyphon (TPCT) for the cooling devices has the limitation due to the phase change of the working fluid assisted by gravity force. Due to the complex phenomenon of two-phase flow, it is required to understand what happened in TPCT. The visualization of the thermosyphon and heat pipe is investigated for the decrease of thermal resistance and enhancement of operation limit. Weibel et al. investigated capillary-fed boiling of water with porous sintered powder wick structure using high speed camera. At the high heat flux condition, dry-out phenomenon and a thin liquid film are observed at the porous wick structure. Wong and Kao investigated the evaporation and boiling process of mesh wicked heat pipe using optical camera. At the high heat flux condition, the water filing became thin and partial dry-out was observed in the evaporator section. Our group suggested the concept of a hybrid heat pipe with control rod as Passive IN-core Cooling System (PINCs) for decay heat removal for advanced nuclear power plant. The hybrid heat pipe is the combination of the heat pipe and control rod. It is necessary for PINCs to contain a neutron absorber (B{sub 4}C) to have the ability of reactivity control. It has annular vapor space and

  2. Deliberate Microbial Infection Research Reveals Limitations to Current Safety Protections of Healthy Human Subjects.

    Science.gov (United States)

    Evers, David L; Fowler, Carol B; Mason, Jeffrey T; Mimnall, Rebecca K

    2015-08-01

    Here we identify approximately 40,000 healthy human volunteers who were intentionally exposed to infectious pathogens in clinical research studies dating from late World War II to the early 2000s. Microbial challenge experiments continue today under contemporary human subject research requirements. In fact, we estimated 4,000 additional volunteers who were experimentally infected between 2010 and the present day. We examine the risks and benefits of these experiments and present areas for improvement in protections of participants with respect to safety. These are the absence of maximum limits to risk and the potential for institutional review boards to include questionable benefits to subjects and society when weighing the risks and benefits of research protocols. The lack of a duty of medical care by physician-investigators to research subjects is likewise of concern. The transparency of microbial challenge experiments and the safety concerns raised in this work may stimulate further dialogue on the risks to participants of human experimentation.

  3. Biasing, operation and parasitic current limitation in single device equivalent to CMOS, and other semiconductor systems

    Science.gov (United States)

    Welch, James D.

    2003-09-23

    Disclosed are semiconductor devices including at least one junction which is rectifying whether the semiconductor is caused to be N or P-type, by the presence of applied gate voltage field induced carriers in essentially intrinsic, essentially homogeneously simultaneously containing both N and P-type metallurgical dopants at substantially equal doping levels, essentially homogeneously simultaneously containing both N and P-type metallurgical dopants at different doping levels, and containing a single metallurgical doping type, and functional combinations thereof. In particular, inverting and non-inverting gate voltage channel induced semiconductor single devices with operating characteristics similar to conventional multiple device CMOS systems, which can be operated as modulators, are disclosed as are a non-latching SCR and an approach to blocking parasitic currents utilizing material(s) which form rectifying junctions with both N and P-type semiconductor whether metallurigically or field induced.

  4. Invited review current progress and limitations of spider silk for biomedical applications.

    Science.gov (United States)

    Widhe, Mona; Johansson, Jan; Hedhammar, My; Rising, Anna

    2012-06-01

    Spider silk is a fascinating material combining remarkable mechanical properties with low density and biodegradability. Because of these properties and historical descriptions of medical applications, spider silk has been proposed to be the ideal biomaterial. However, overcoming the obstacles to produce spider silk in sufficient quantities and in a manner that meets regulatory demands has proven to be a difficult task. Also, there are relatively few studies of spider silk in biomedical applications available, and the methods and materials used vary a lot. Herein we summarize cell culture- and in vivo implantation studies of natural and synthetic spider silk, and also review the current status and future challenges in the quest for a large scale production of spider silk for medical applications. Copyright © 2011 Wiley Periodicals, Inc.

  5. Protein-Protein Interactions: Gene Acronym Redundancies and Current Limitations Precluding Automated Data Integration.

    Science.gov (United States)

    Casado-Vela, Juan; Matthiesen, Rune; Sellés, Susana; Naranjo, José Ramón

    2013-05-31

    Understanding protein interaction networks and their dynamic changes is a major challenge in modern biology. Currently, several experimental and in silico approaches allow the screening of protein interactors in a large-scale manner. Therefore, the bulk of information on protein interactions deposited in databases and peer-reviewed published literature is constantly growing. Multiple databases interfaced from user-friendly web tools recently emerged to facilitate the task of protein interaction data retrieval and data integration. Nevertheless, as we evidence in this report, despite the current efforts towards data integration, the quality of the information on protein interactions retrieved by in silico approaches is frequently incomplete and may even list false interactions. Here we point to some obstacles precluding confident data integration, with special emphasis on protein interactions, which include gene acronym redundancies and protein synonyms. Three human proteins (choline kinase, PPIase and uromodulin) and three different web-based data search engines focused on protein interaction data retrieval (PSICQUIC, DASMI and BIPS) were used to explain the potential occurrence of undesired errors that should be considered by researchers in the field. We demonstrate that, despite the recent initiatives towards data standardization, manual curation of protein interaction networks based on literature searches are still required to remove potential false positives. A three-step workflow consisting of: (i) data retrieval from multiple databases, (ii) peer-reviewed literature searches, and (iii) data curation and integration, is proposed as the best strategy to gather updated information on protein interactions. Finally, this strategy was applied to compile bona fide information on human DREAM protein interactome, which constitutes liable training datasets that can be used to improve computational predictions.

  6. Scanning fast and slow: current limitations of 3 Tesla functional MRI and future potential

    Science.gov (United States)

    Boubela, Roland N.; Kalcher, Klaudius; Nasel, Christian; Moser, Ewald

    2014-02-01

    Functional MRI at 3T has become a workhorse for the neurosciences, e.g., neurology, psychology, and psychiatry, enabling non-invasive investigation of brain function and connectivity. However, BOLD-based fMRI is a rather indirect measure of brain function, confounded by fluctuation related signals, e.g. head or brain motion, brain pulsation, blood flow, intermixed with susceptibility differences close or distant to the region of neuronal activity. Even though a plethora of preprocessing strategies have been published to address these confounds, their efficiency is still under discussion. In particular, physiological signal fluctuations closely related to brain supply may mask BOLD signal changes related to "true" neuronal activation. Here we explore recent technical and methodological advancements aimed at disentangling the various components, employing fast multiband vs. standard EPI, in combination with fast temporal ICA.Our preliminary results indicate that fast (TRbrain, even at a rather coarse macroscopic level, we should be very cautious in the interpretation of neuroscientific findings, in particular when comparing different groups (e.g., age, sex, medication, pathology, etc.). From a technical point of view our goal should be to sample brain activity at layer specific resolution with low TR, covering as much of the brain as possible without violating SAR limits. We hope to stimulate discussion towards a better understanding and a more quantitative use of fMRI.

  7. Human immune system mice: current potential and limitations for translational research on human antibody responses.

    Science.gov (United States)

    Vuyyuru, Raja; Patton, John; Manser, Tim

    2011-12-01

    It has recently become possible to generate chimeric mice durably engrafted with many components of the human immune system (HIS mice). We have characterized the maturation and function of the B cell compartment of HIS mice. The antibody response of HIS mice to T cell-dependent B cell antigens is limited, and contributing factors may be the general immaturity of the B cell compartment, infrequent helper T cells selected on human MHC class II antigens, and incomplete reconstitution of secondary lymphoid organs and their microenvironments. In contrast, HIS mice generate protective antibody responses to the bacterium Borrelia hermsii, which acts as a T cell-independent antigen in mice, but do not respond to purified polysaccharide antigens (PPS). We speculate that the anti-B. hermsii response of HIS mice is derived from an abundant B cell subset that may be analogous to B1 B cells in mice. We suggest that failure of HIS mice to respond to PPS is due to the lack of a B cell subset that may originate from adult bone marrow and is highly dependent on human interleukin-7 for development.

  8. Four point function of R-currents in N=4 SYM in the Regge limit at weak coupling

    Energy Technology Data Exchange (ETDEWEB)

    Bartels, J.; Mischler, A.M.; Salvadore, M. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2008-04-15

    We compute, in N = 4 super Yang-Mills, the four point correlation function of R-currents in the Regge limit in the leading logarithmic approximation at weak coupling. Such a correlator is the closest analog to photon-photon scattering within QCD, and there is a well defined procedure to perform the analogous computation at strong coupling via AdS/CFT. The main result of this paper is, on the gauge theory side, the proof of Regge factorization and the explicit computation of the R-current impact factors. (orig.)

  9. Theoretical Limit to the Laser Threshold Current Density in an InGaN Quantume Well Laser

    Energy Technology Data Exchange (ETDEWEB)

    Amano, H; Chow, W W; Han, J

    1998-10-09

    This paper describes an investigation of the spontaneous emission limit to the laser threshold current density in an InGaN quantum well laser. The peak gain and spontaneous emission rate as functions of carrier density are com- puted using a microscopic laser theory. From these quantities, the minimum achievable threshold current density is determined for a given threshold gain. The dependence on quantum well width, and the effects of inhomogeneous broadening due to spatial alloy variations are discussed. Also, comparison with experiments is made.

  10. 故障电流限制器发展现状与应用前景%Current Status and Application Prospect of Fault Current Limiters

    Institute of Scientific and Technical Information of China (English)

    郑健超

    2014-01-01

    To meet the challenge of ever-increasing fault current level in the power grid, various fault current limiters have been proposed and developed over the past decades. However, with a few exceptions, there has been little progress in developing products feasible for commercial applications. This paper attempts to give an overview of current states and technical features of the leading fault current limiters, and to analyze the restrictions to its penetration into power market. Finally, the development trend and future prospect of FCL are projected, with special reference to the recent innovation tendency in making FCL more competitive, including extending its applications to smart grid and further improving its tech-economic performance by technology convergence.%为了应对电网故障电流水平日益增长的挑战,过去数十年,提出并开发了各类故障电流限制器。但是,除少数例外,适合于商业应用的产品开发却进展缓慢。该文概括介绍了主要限流器的发展现状及技术特点,分析了影响限流器进入电力市场的制约因素。最后,预测了限流器的发展趋势和未来前景,重点讲述为提高限流器的竞争力,近年来技术创新的趋向,包括将限流器的应用扩展到智能电网,通过技术融合进一步改善其技术经济性能等。

  11. Fault ride-through enhancement of fixed speed wind turbine using bridge-type fault current limiter

    Directory of Open Access Journals (Sweden)

    Mostafa I. Marei

    2016-05-01

    Full Text Available The interaction between wind energy turbines and the grid results in two main problems, increasing the short-circuit level and reducing the Fault Ride-Through (FRT capability during faults. The objective of this paper is to solve these problems, for fixed speed Wind Energy Systems (WECS, utilizing the bridge-type Fault Current Limiter (FCL with a discharging resistor. A simple cascaded control system is proposed for the FCL to regulate the terminal voltage of the generator and limit the current. The system is simulated on PSCAD/EMTDC software to evaluate the dynamic performance of the proposed WECS compensated by FCL. The simulation results show the potentials of the FCL as a simple and effective method for solving grid interconnection problems of WECS.

  12. 基于限流电抗电流控制的新型桥式固态限流器%A Novel Bridge-Type Solid-State Fault Current Limiter Based on Limiting Reactance Current Control

    Institute of Scientific and Technical Information of China (English)

    范宇; 江道灼; 吕文韬

    2014-01-01

    On the basis of thyristors based single-phase/three-phase bridge-type solid-state fault current limiter (SSFCL), its topological structure is improved:thyristors in rectifier and freewheel bridges are substituted by diodes to decrease the number of power electronic controllable elements. A limiting reactance current control based control strategy is proposed, that is, through controlling the switching off/on of full-controllable power electronic switch elements in current limiting reactance branch the current flowing through current limiting reactance is kept stable to limit the amplitude of fault current in transmission line. The analysis on entire working process of the improved SSFCL is given. Based on the topological structure and working principle, the control system and element parameters are designed and corresponding simulation model is established. Simulation results show that under different fault conditions the improved SSFCL works correctly and slightly affects on non-fault phase;it can control fault current accurately and the value of limited current can be flexible regulated, so after the clearance of the fault the transmission line can be back to normal operation rapidly, besides the improve SSFCL is suitable for following conditions:many times of fault occurred in a short-term, non-full-phase operation of transmission line and automatic reclosure.%在基于晶闸管的单相/三相桥式固态限流器基础上,对其拓扑结构进行改进,其中整流桥路、续流桥路均采用二极管,减少电力电子可控元件的数量。提出了基于限流电抗电流控制的控制策略,通过控制限流电抗支路的全控电力电子开关器件的关断与导通,保持限流电抗电流稳定,限制线路故障电流的幅值,并对整个工作过程给出了完整分析。根据拓扑结构与工作原理,对控制系统与元件参数进行设计并进行建模仿真。结果表明该限流器正确工作于不同故障且

  13. A trap-limited-current-based model of Meyer-Neldel rule and its connection to persistent photocurrent

    Science.gov (United States)

    Tian, Ye; Jiang, Lianjun; Zhang, Xuejun; Zhang, Guangfu

    2016-10-01

    A theoretical model is established to describe the emergence of the Meyer-Neldel rule (MNR) based on trap-limited current (TLC) theory. The model produces both MNR and anti-MNR behavior, and is available to various trap distributions. Moreover, TLC-based MNR is connected to persistent photocurrent (PPC) phenomenon. The information from MNR and PPC as well as their connection can be used to probe the distribution of the traps in materials.

  14. Some current problems in perovskite nano-ferroelectrics and multiferroics: kinetically-limited systems of finite lateral size

    Science.gov (United States)

    Scott, James F.; Schilling, Alina; Rowley, S. E.; Gregg, J. Marty

    2015-06-01

    We describe some unsolved problems of current interest; these involve quantum critical points in ferroelectrics and problems which are not amenable to the usual density functional theory, nor to classical Landau free energy approaches (they are kinetically limited), nor even to the Landau-Kittel relationship for domain size (they do not satisfy the assumption of infinite lateral diameter) because they are dominated by finite aperiodic boundary conditions.

  15. Stochastic dynamics of extended objects in driven systems II: Current quantization in the low-temperature limit

    Science.gov (United States)

    Catanzaro, Michael J.; Chernyak, Vladimir Y.; Klein, John R.

    2016-12-01

    Driven Langevin processes have appeared in a variety of fields due to the relevance of natural phenomena having both deterministic and stochastic effects. The stochastic currents and fluxes in these systems provide a convenient set of observables to describe their non-equilibrium steady states. Here we consider stochastic motion of a (k - 1) -dimensional object, which sweeps out a k-dimensional trajectory, and gives rise to a higher k-dimensional current. By employing the low-temperature (low-noise) limit, we reduce the problem to a discrete Markov chain model on a CW complex, a topological construction which generalizes the notion of a graph. This reduction allows the mean fluxes and currents of the process to be expressed in terms of solutions to the discrete Supersymmetric Fokker-Planck (SFP) equation. Taking the adiabatic limit, we show that generic driving leads to rational quantization of the generated higher dimensional current. The latter is achieved by implementing the recently developed tools, coined the higher-dimensional Kirchhoff tree and co-tree theorems. This extends the study of motion of extended objects in the continuous setting performed in the prequel (Catanzaro et al.) to this manuscript.

  16. Stochastic Dynamics of Extended Objects in Driven Systems II: Current Quantization in the Low-Temperature Limit

    CERN Document Server

    Catanzaro, Michael J; Klein, John R

    2016-01-01

    Driven Langevin processes have appeared in a variety of fields due to the relevance of natural phenomena having both deterministic and stochastic effects. The stochastic currents and fluxes in these systems provide a convenient set of observables to describe their non-equilibrium steady states. Here we consider stochastic motion of a (k - 1)-dimensional object, which sweeps out a k-dimensional trajectory, and gives rise to a higher k-dimensional current. By employing the low-temperature (low-noise) limit, we reduce the problem to a discrete Markov chain model on a CW complex, a topological construction which generalizes the notion of a graph. This reduction allows the mean fluxes and currents of the process to be expressed in terms of solutions to the discrete Supersymmetric Fokker-Planck (SFP) equation. Taking the adiabatic limit, we show that generic driving leads to rational quantization of the generated higher dimensional current. The latter is achieved by implementing the recently developed tools, coined...

  17. Self-rehealing characteristics of a sodium current limiter and its over current coordination for low voltage distribution systems; Natoriumu (Na) genryu soshi no jiko fukkyu tokusei to teiatsu haiden kairo oyo ni okeru kadenryu kyocho

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Y.; Hamano, S.; Mori, T. [Mitsubishi Electric Corp., Tokyo (Japan)

    1994-07-20

    As one of the short circuits protection techniques in a power circuit, there is a technique called the current-limiting breaking. When a short circuit current commences to flow after a short circuit occurs, this technique limits and breaks this current under a certain value by some measures before this current reaches to the crest value. There is a current-limiting fuse in the best known one as a functional element doing the current-limiting breaking. However in case of a current-limiting fuse, when an element is fused off, because a current can not be flowed, it has to be replaced. As a new element to eliminate this defect and moreover with a current-limiting function, a self-rehealing type current-limiting element possessing the alkaline metal, Na as an element has been developed. In this report, as for this element called Na current-limiting element, together with elucidating a rehealing process after the current-limiting action experimentally in detail, an overcurrent coordination is investigated when this element is applied to a main circuit of the control center, which is one of the low voltage distribution systems. 5 refs., 8 figs., 1 tab.

  18. Solid-State Fault Current Limiter Development : Design and Testing Update of a 15kV SSCL Power Stack

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Ram Adapa; Mr. Dante Piccone

    2012-04-30

    ABSTRACT The Solid-State Fault Current Limiter (SSCL) is a promising technology that can be applied to utility power delivery systems to address the problem of increasing fault currents associated with load growth. As demand continues to grow, more power is added to utility system either by increasing generator capacity or by adding distributed generators, resulting in higher available fault currents, often beyond the capabilities of the present infrastructure. The SSCL is power-electronics based equipment designed to work with the present utility system to address this problem. The SSCL monitors the line current and dynamically inserts additional impedance into the line in the event of a fault being detected. The SSCL is based on a modular design and can be configured for 5kV through 69kV systems at nominal current ratings of 1000A to 4000A. Results and Findings This report provides the final test results on the development of 15kV class SSCL single phase power stack. The scope of work included the design of the modular standard building block sub-assemblies, the design and manufacture of the power stack and the testing of the power stack for the key functional tests of continuous current capability and fault current limiting action. Challenges and Objectives Solid-State Current Limiter technology impacts a wide spectrum of utility engineering and operating personnel. It addresses the problems associated with load growth both at Transmission and Distribution class networks. The design concept is pioneering in terms of developing the most efficient and compact power electronics equipment for utility use. The initial test results of the standard building blocks are promising. The independent laboratory tests of the power stack are promising. However the complete 3 phase system needs rigorous testing for performance and reliability. Applications, Values, and Use The SSCL is an intelligent power-electronics device which is modular in design and can provide current

  19. Low Resolution Limits and Inaccurate Algorithms Decrease Significantly the Value of Late Loss in Current Drug-Eluting Stent Trials

    Directory of Open Access Journals (Sweden)

    Johannes B. Dahm

    2012-01-01

    Full Text Available Quantitative coronary and vascular angiography (QCA resp., QVA remains the current gold standard for evaluation of restenosis. Late loss as one of the most commonly accepted parameters to highlight efficacy of the various devices has shown high correlation to clinical parameters but, surprisingly, has no impact on the evaluation of the remaining amount of restenostic tissue. The current clinical practice leads to unrealistic late loss calculations. Smaller late loss differences are usually not greater than the inherited resolution limits of QCA, which is especially the case in small differences between the various stents in the drug-eluting stent era. Late loss include additional systematic and random errors, due to the fact that measurements were taken at two different time points including the inherited resolution and calibration limits of QCA on two occasions. Due to the limited value of late loss in discriminating the small differences between the one and other DES, late lumen area loss and clearly defined calculation algorithms (e.g., MLD-relocation should be used in future DES studies also to fulfill the more stringent regulatory requirements.

  20. 某型导弹舵机限流电路分析%Missile Servo Current-limiting Circuit Analysis

    Institute of Scientific and Technical Information of China (English)

    王小波; 付克亚

    2016-01-01

    The current of current-limiting circuit frequently surpasses its nomial value in testing servo control circuit of a certain type missile.This paper analyses the working principle of current-limiting circuit,identifies its main influence factors,and brings forward the corresponding solution to solve such failure and promote the passing ratio of control circuit assembly test.The feasibility and effectiveness of the solution method is validat-ed in practice.%某型导弹舵机控制电路在测试时,经常出现限幅电流超差故障。该文从分析限流电路工作原理出发,查找出其主要影响因素,并有针对性的提出解决方法,以解决此类故障,提高控制电路装配测试合格率。通过生产实际,验证了这些解决方法的可行性和有效性。

  1. Assessment of the impact of HTSCs on superconducting fault-current limiters. [High Temperature SuperConductors (HTSCs)

    Energy Technology Data Exchange (ETDEWEB)

    Giese, R.F. (Argonne National Lab., IL (United States)); Runde, M. (Energiforsyningens Forskningsinstitutt A/S, Trondheim (Norway))

    1993-01-01

    The possible impact of nitrogen-cooled superconductors on the desip and cost of superconducting fault-current limiters is assessed by considering the technical specifications such devices must meet and by comparing material properties of 77-K and 4-K superconductors. The main advantages of operating superconductors at 77 K are that the refrigeration operating cost is reduced by a factor of up to 25 and the refrigeration capital cost is reduced by a factor of up to 10. The heat capacity is several orders of magnitude Larger at 77 K and at 4 K. This phenomenon increases conductor stability against flux jumps but makes switching from the superconducting to the normal state slow and difficult. Therefore, a high critical current density, probably at least 10[sup 5] A/cm[sup 2], is required.

  2. Upper Extremity Injured Workers Stratified by Current Work Status: An Examination of Health Characteristics, Work Limitations and Work Instability

    Directory of Open Access Journals (Sweden)

    H Grant

    2010-06-01

    Full Text Available Background: Upper extremity injured workers are an under-studied population. A descriptive comparison of workers with shoulder, elbow and hand injuries reporting to a Canadian Workplace Safety and Insurance Board (WSIB clinic was undertaken.Objective: To determine if differences existed between injury groups stratified by current work status.Methods: All WSIB claimants reporting to our upper extremity clinic between 2003 and 2008 were approached to participate in this descriptive study. 314 working and 146 non-working WSIB claimants completed the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH; Short Form health survey (SF36; Worker’s Limitations Questionnaire and the Work Instability Scale. Various parametric and non-parametric analyses were used to assess significant differences between groups on demographic, work and health related variables.Results: Hand, followed by the shoulder and elbow were the most common site of injury. Most non-workers listed their current injury as the reason for being off work, and attempted to return to work once since their injury occurrence. Non-workers and a subset of workers at high risk for work loss showed significantly worse mental functioning. Workers identified physical demands as the most frequent injury-related on the job limitation. 60% of current workers were listed as low risk for work loss on the Work Instability Scale.Conclusions: Poorer mental functioning, being female and sustaining a shoulder injury were risk factors for work instability. Our cohort of injured non-workers were unable to return to work due to their current injury, reinforcing the need to advocate for modified duties, shorter hours and a work environment where stress and injury recurrence is reduced. Future studies examining pre-injury depression as a risk factor for prolonged work absences are warranted.

  3. Current meter data from moored current meter casts in the SW Pacific (limit-147 E to 140 W) as part of the Equatorial Pacific Ocean Climate Studies (EPOCS) project from 29 September 1985 to 01 April 1986 (NODC Accession 8800136)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter data were collected using moored current meter casts in the SW Pacific (limit-147 E to 140 W) from September 29, 1985 to June 1, 1986. Data were...

  4. Current meter data from moored current meter casts in the Northwest Atlantic Ocean (limit-40 W) as part of the Outer Continental Shelf - Georges Bank (OCS -Georges Bank) project from 27 October 1980 - 01 November 1982 (NODC Accession 8600087)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter data were collected using moored current meter casts in the Northwest Atlantic Ocean (limit-40 W) from November 27, 1980 to November 1, 1982. Data were...

  5. Current meter data from moored current meter casts in the Northwest Atlantic Ocean (limit -40 W) as part of the Ocean Dumping project, 24 May 1990 - 17 June 1991 (NODC Accession 9300112)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter data were collected using moored current meter casts in the Northwest Atlantic Ocean (limit -40 W) from May 24, 1990 to June 17, 1991. Data were...

  6. Temperature and current profiles from BT and current profilers from DRIFTING PLATFORMS from the SW Atlantic (limit-20 W) and other locations from 01 January 1993 to 31 December 1995 (NODC Accession 9600085)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature and current data from BT cast and current profilers from DRIFTING PLATFORMS from the SW Atlantic (limit-20 W) and other locations. Data was collected by...

  7. Current components, physical, and other data from moored current meters and CTD casts from NOAA Ship Discoverer and other platforms from the NE Pacific (limit-180) from 1993-08-18 to 1994-09-28 (NODC Accession 9500006)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current components, physical, and other data from moored current meters and CTD casts from NOAA Ship DISCOVERER and other platforms from the NE Pacific (limit-180)....

  8. Current meter data from moored current meter casts in the Northwest Atlantic Ocean (limit-40 W) as part of the Outer Continental Shelf - Georges Bank (OCS -Georges Bank) project from 25 October 1980 - 01 November 1982 (NODC Accession 8600046)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter data were collected using moored current meter casts in the Northwest Atlantic Ocean (limit-40 W) from October 25, 1980 to November 1, 1982. Data were...

  9. Current components, physical, and other data from moored current meters and CTD casts from NOAA Ship Discoverer and other platforms from the NE Pacific (limit-180) from 1994-04-22 to 1995-08-20 (NODC Accession 9500150)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current components, physical, and other data from moored current meters and CTD casts from NOAA Ship DISCOVERER and other platforms from the NE Pacific (limit-180)....

  10. Fault Current Limitation and Analysis of Current Limiting Characteristic for Multi-terminal VSC-HVDC DC Lines%多端VSC-HVDC直流线路故障限流及限流特性分析

    Institute of Scientific and Technical Information of China (English)

    刘剑; 邰能灵; 范春菊; 郑晓冬; 唐跃中

    2016-01-01

    基于电压源型换流器(voltage source converters,VSC)的多端柔性直流系统中直流线路的故障电流上升速度快、电流峰值大。然而具有大容量、快切断能力的高压直流断路器正在研制中。结合目前直流断路器开断容量水平,该文提出通过在直流线路两端串入限流电路的方法来限制故障电流的峰值和电流的上升速度率,并给出相关参数的理论计算方法。对该电路的限流特性进行分析与对比,结果表明,该限流电路能有效抑制故障电流,降低了对直流断路器开断容量和开断速度的要求。在该限流电路的基础上,提出一种多端VSC-HVDC 直流线路故障处理方案。仿真分析表明,该故障处理方案能够有效抑制直流线路故障电流以及 IGBT 并联二极管电流,故障切除后非故障系统能保持正常运行,可以有效地增强多端VSC-HVDC系统对直流线路故障的处理能力。%The fault current of DC line in multi-terminal HVDC system based on voltage source converters (VSC) increases quickly with large peak, while the DC circuit breaker with large capacity and fast breaking speed is still under development. Combined with the capacity level of DC circuit breaker breaking, a current limiting circuit was proposed to limit the peak and rising rate of fault current by connecting it to DC line ends. Theoretical calculation method for the circuit parameters was also given. The analysis results about the circuit and the comparison with other methods show that the proposed circuit is able to limit the fault current effectively and reduce the requirement for DC breaker capacity and speed. Based on the circuit, a fault-handling scheme for DC lines in multi-terminal VSC-HVDC was proposed. The simulation results show that the proposed scheme is capable of limiting fault current of DC lines and parallel diodes effectively, and non-fault system can maintain normal operation after fault

  11. Optimal allocation of fault current limiters for sustaining overcurrent relays coordination in a power system with distributed generation

    Directory of Open Access Journals (Sweden)

    A. Elmitwally

    2015-12-01

    Full Text Available This paper addresses the problem of overcurrent relays (OCRs coordination in the presence of DGs. OCRs are optimally set to work in a coordinated manner to isolate faults with minimal impacts on customers. The penetration of DGs into the power system changes the fault current levels seen by the OCRs. This can deteriorate the coordinated operation of OCRs. Operation time difference between backup and main relays can be below the standard limit or even the backup OCR can incorrectly work before the main OCR. Though resetting of OCRs is tedious especially in large systems, it cannot alone restore the original coordinated operation in the presence of DGs. The paper investigates the optimal utilization of fault current limiters (FCLs to maintain the directional OCRs coordinated operation without any need to OCRs resetting irrespective of DGs status. It is required to maintain the OCRs coordination at minimum cost of prospective FCLs. Hence, the FCLs location and sizing problem is formulated as a constrained multi-objective optimization problem. Multi-objective particle swarm optimization is adopted for solving the optimization problem to determine the optimal locations and sizes of FCLs. The proposed algorithm is applied to meshed and radial power systems at different DGs arrangements using different types of FCLs. Moreover, the OCRs coordination problem is studied when the system includes both directional and non-directional OCRs. Comparative analysis of results is provided.

  12. 饱和铁心型超导限流器%Saturated iron - core superconducting fault current limiter

    Institute of Scientific and Technical Information of China (English)

    庞骁刚; 龚伟志; 洪辉; 任安林; 信赢

    2012-01-01

    饱和铁心型超导限流器具有限流功能可靠、输电稳态损耗小、限流恢复时间短等优异特性.根据其工作原理,一方面,用于直流励磁的超导绕组自身不承受短路电流冲击,这避免了其它类型超导限流器中由于超导绕组失超所带来的诸多技术难题;另一方面,其主体电抗器可以借鉴成熟的铁心电抗器技术.因此,饱和铁心型超导限流器的以其优异的性能特性和成熟的工程实现技术,成为迄今为止人们研究的各类超导限流器中的最具实用价值的一种.在电网容量不断扩大,智能化水平不断提高的今天,饱和铁心型超导限流器有非常广阔的应用前景.文中将叙述饱和铁心型超导限流器的基本原理、结构形式、功能特性,并对已在云南普吉变电站挂网运行的35kV/90MVA超导限流器进行简要介绍.%Saturated iron -core superconducting fault current limiters have some superior performance features, such as very low operation loss at normal power transmission, high impedance at fault current limiting, immediately reacting, and fast recovering. Thinks to its working mechanism, there is no risk of quench to the superconductor coil on the impact of the fault current, so complex mechanical, electrical and thermal protection measures can be avoided. The complicity to deal with a quench of superconductor might be a severe technical barrier for other types of superconducting fault current limiiers. In addition, the reactor of the device is mainly composed by iron cores and copper coils, which can be built with the technology for conventional transformers or reactors. For these reasons, this kind of superconducting fault current limiters is considered the most practically viable device in industrial applications. In this paper, the fundamental principles, the structures and the performance features of saturated iron core SFCLs are introduced. The specifications, testing results, and the operational

  13. Zonal and Meridional Ocean Currents at TOPEX/Poseidon and JASON-1 Crossovers around Taiwan: Error Analysis and Limitation

    Directory of Open Access Journals (Sweden)

    Cheinway Hwang

    2008-01-01

    Full Text Available A crossover method for determining zonal and meridional ocean current components is examined using data at three crossovers of TOPEX/Poseidon and JASON-1 ground tracks over 2002 - 2006. To implement this method, a geoid model around Taiwan is constructed using surface and airborne gravity data. The modeled and observed geoidal heights at coastal benchmarks are consistent to 5 cm RMS with the means removed. The error and limitation of this method are discussed, concluding that, in order to obtain current velocities at a 10 cm s-1 accuracy and a 6-km resolution, the dynamic ocean topography (DOT at a mm-level accuracy is needed, which is not possible to achieve today. By filtering DOT to a spatial scale of 100 km or coarser, a 10 cm s-1 accuracy of velocity may be obtained. One crossover (A is situated south of Taiwan and near the Kuroshio, the second (B is at the axis of the Kuroshio and the third is located in the northern Taiwan Strait. These three crossovers feature different ocean current patterns. At a spatial scale of 120 km, the agreement among the altimeter, the Princeton Ocean Model (POM, and the drifter-derived velocities is the best at B, followed by that at A, and then C. In fact, at C the altimeter-derived velocities contradict the POM-derived values, and the tide model error is to be blamed. Further improvement on geoid modeling is suggested.

  14. Estimation of electron mobility of n-doped 4, 7-diphenyl-1, 10-phenanthroline using space-charge-limited currents

    Institute of Scientific and Technical Information of China (English)

    Khizar-ul-Haq; Khan M A; Jiang Xueyin; Zhang Zhilin; Zhang Xiaowen; Zhang Liang; Li Jun

    2009-01-01

    The electron mobilities of 4, 7-diphenyl-1, 10-phenanthroline (BPhen) doped 8-hydroxyquinolinatolithium (Liq) at various thicknesses (50-300 nm) have been estimated by using space-charge-limited current measurements. It is observed that the electron mobility of 33 wt% Liq doped BPhen approaches its true value when the thickness is more than 200 nm. The electron mobility of 33 wt% Liq doped BPhen at 300 nm is found to be ~5.2 × 10~(-3) cm~2/(V·s) (at 0.3 MV/cm) with weak dependence on electric field, which is about one order of magnitude higher than that of pristine BPhen (3.4 × 10~(-4) cm~2/(V·s)) measured by SCLC. For the typical thickness of organic light-emitting devices, the electron mobility of doped BPhen is also investigated.

  15. Study on application of a high-speed trigger-type SFCL (TSFCL) for interconnection of power systems with different reliabilities

    Science.gov (United States)

    Kim, Hye Ji; Yoon, Yong Tae

    2016-11-01

    Interconnection of power systems is one effective way to improve power supply reliability. However, differences in the reliability of each power system create a greater obstacle for the stable interconnection of power systems, as after interconnection a high-reliability system is affected by frequent faults in low reliability side systems. Several power system interconnection methods, such as the back-to-back method and the installation of either transformers or series reactors, have been investigated to counteract the damage caused by faults in the other neighboring systems. However, these methods are uneconomical and require complex operational management plans. In this work, a high-speed trigger-type superconducting fault current limiter (TSFCL) with large-impedance is proposed as a solution to maintain reliability and power quality when a high reliability power system is interconnected with a low reliability power system. Through analysis of the reliability index for the numerical examples obtained from a PSCAD/EMTDC simulator, a high-speed TSFCL with a large-impedance is confirmed to be effective for the interconnection between power systems with different reliabilities.

  16. Opportunities to overcome the current limitations and challenges for efficient microbial production of optically pure lactic acid.

    Science.gov (United States)

    Abdel-Rahman, Mohamed Ali; Sonomoto, Kenji

    2016-10-20

    There has been growing interest in the microbial production of optically pure lactic acid due to the increased demand for lactic acid-derived environmentally friendly products, for example biodegradable plastic (poly-lactic acid), as an alternative to petroleum-derived materials. To maximize the market uptake of these products, their cost should be competitive and this could be achieved by decreasing the production cost of the raw material, that is, lactic acid. It is of great importance to isolate and develop robust and highly efficient microbial lactic acid producers. Alongside the fermentative substrate and concentration, the yield and productivity of lactic acid are key parameters and major factors in determining the final production cost of lactic acid. In this review, we will discuss the current limitations and challenges for cost-efficient microbial production of optically pure lactic acid. The main obstacles to effective fermentation are the use of food resources, indirect utilization of polymeric sugars, sensitivity to inhibitory compounds released during biomass treatments, substrate inhibition, decreased lactic acid yield and productivity, inefficient utilization of mixed sugars, end product inhibition, increased use of neutralizing agents, contamination problems, and decreased optical purity of lactic acid. Furthermore, opportunities to address and overcome these limitations, either by fermentation technology or metabolic engineering approaches, will be introduced and discussed.

  17. Use of cone beam computed tomography in implant dentistry: current concepts, indications and limitations for clinical practice and research.

    Science.gov (United States)

    Bornstein, Michael M; Horner, Keith; Jacobs, Reinhilde

    2017-02-01

    Diagnostic radiology is an essential component of treatment planning in the field of implant dentistry. This narrative review will present current concepts for the use of cone beam computed tomography imaging, before and after implant placement, in daily clinical practice and research. Guidelines for the selection of three-dimensional imaging will be discussed, and limitations will be highlighted. Current concepts of radiation dose optimization, including novel imaging modalities using low-dose protocols, will be presented. For preoperative cross-sectional imaging, data are still not available which demonstrate that cone beam computed tomography results in fewer intraoperative complications such as nerve damage or bleeding incidents, or that implants inserted using preoperative cone beam computed tomography data sets for planning purposes will exhibit higher survival or success rates. The use of cone beam computed tomography following the insertion of dental implants should be restricted to specific postoperative complications, such as damage of neurovascular structures or postoperative infections in relation to the maxillary sinus. Regarding peri-implantitis, the diagnosis and severity of the disease should be evaluated primarily based on clinical parameters and on radiological findings based on periapical radiographs (two dimensional). The use of cone beam computed tomography scans in clinical research might not yield any evident beneficial effect for the patient included. As many of the cone beam computed tomography scans performed for research have no direct therapeutic consequence, dose optimization measures should be implemented by using appropriate exposure parameters and by reducing the field of view to the actual region of interest.

  18. Current Treatment Limitations in Age-Related Macular Degeneration and Future Approaches Based on Cell Therapy and Tissue Engineering

    Directory of Open Access Journals (Sweden)

    P. Fernández-Robredo

    2014-01-01

    Full Text Available Age-related macular degeneration (AMD is the leading cause of blindness in the Western world. With an ageing population, it is anticipated that the number of AMD cases will increase dramatically, making a solution to this debilitating disease an urgent requirement for the socioeconomic future of the European Union and worldwide. The present paper reviews the limitations of the current therapies as well as the socioeconomic impact of the AMD. There is currently no cure available for AMD, and even palliative treatments are rare. Treatment options show several side effects, are of high cost, and only treat the consequence, not the cause of the pathology. For that reason, many options involving cell therapy mainly based on retinal and iris pigment epithelium cells as well as stem cells are being tested. Moreover, tissue engineering strategies to design and manufacture scaffolds to mimic Bruch’s membrane are very diverse and under investigation. Both alternative therapies are aimed to prevent and/or cure AMD and are reviewed herein.

  19. The Importance and Current Limitations of Planetary Boundary Layer (PBL) Retrieval from Space for Land-Atmosphere Coupling Studies

    Science.gov (United States)

    Santanello, J. A., Jr.; Schaefer, A.

    2016-12-01

    There is an established need for improved PBL remote sounding over land for hydrology, land-atmosphere (L-A), PBL, cloud/convection, pollution/chemistry studies and associated model evaluation and development. Most notably, the connection of surface hydrology (through soil moisture) to clouds and precipitation relies on proper quantification of water's transport through the coupled system, which is modulated strongly by PBL structure, growth, and feedback processes such as entrainment. In-situ (ground-based or radiosonde) measurements will be spatially limited to small field campaigns for the foreseeable future, so satellite data is a must in order to understand these processes globally. The scales of these applications require diurnal resolution (e.g. 3-hourly or finer) at PBL coupling and water and energy cycles at their native scales. Today's satellite sensors (e.g. advanced IR, GEO, lidar, GPS-RO) do not reach close to these targets in terms of accuracy or resolution, and each of these sensors has some advantages but even more limitations that make them impractical for PBL and L-A studies. Unfortunately, there is very little attention or planning (short or long-term) in place for improving lower tropospheric sounding over land, and as a result PBL and L-A interactions have been identified as `gaps' in current programmatic focal areas. It is therefore timely to assess how these technologies can be leveraged, combined, or evolved in order to form a dedicated mission or sub-mission to routinely monitor the PBL on diurnal timescales. In addition, improved PBL monitoring from space needs to be addressed in the next Decadal Survey. In this talk, the importance of PBL information (structure, evolution) for L-A coupling diagnostics and model development will be summarized. The current array of PBL retrieval methods and products from space will then be assessed in terms of meeting the needs of these models, diagnostics, and scales, with a look forward as to how this can

  20. Imaging of Myocardial Fibrosis in Patients with End-Stage Renal Disease: Current Limitations and Future Possibilities

    Science.gov (United States)

    Patel, A. S.; Marsh, A.-M.; McAdam, J.; McCann, G. P.; Burton, J. O.

    2017-01-01

    Cardiovascular disease in patients with end-stage renal disease (ESRD) is driven by a different set of processes than in the general population. These processes lead to pathological changes in cardiac structure and function that include the development of left ventricular hypertrophy and left ventricular dilatation and the development of myocardial fibrosis. Reduction in left ventricular hypertrophy has been the established goal of many interventional trials in patients with chronic kidney disease, but a recent systematic review has questioned whether reduction of left ventricular hypertrophy improves cardiovascular mortality as previously thought. The development of novel imaging biomarkers that link to cardiovascular outcomes and that are specific to the disease processes in ESRD is therefore required. Postmortem studies of patients with ESRD on hemodialysis have shown that the extent of myocardial fibrosis is strongly linked to cardiovascular death and accurate imaging of myocardial fibrosis would be an attractive target as an imaging biomarker. In this article we will discuss the current imaging methods available to measure myocardial fibrosis in patients with ESRD, the reliability of the techniques, specific challenges and important limitations in patients with ESRD, and how to further develop the techniques we have so they are sufficiently robust for use in future clinical trials.

  1. Classification of chronic rhinosinusitis according to a nasal polyp and tissue eosinophilia: limitation of current classification system for Asian population

    Science.gov (United States)

    Cho, Sung-Woo; Kim, Dae Woo; Kim, Jeong-Whun; Lee, Chul Hee

    2017-01-01

    Chronic rhinosinusitis (CRS) can be classified according to the presence of a nasal polyp (NP): CRS with NP (CRSwNP) and CRS without NP (CRSsNP). CRSwNP has characteristics with high infiltration of tissue eosinophilia with a burst of Th2 inflammatory cytokine. However recent findings in Eastern Asia countries suggest that CRSwNP can be divided according to the presence of tissue eosinophilia. Thus, CRSwNP can be classified into eosinophilic and noneosinophilic. Eosinophilic CRSwNP seems to have different immunological and clinical feature compared to noneosinophilic CRSwNP. From the same point of view, CRSsNP can also be divided according to tissue eosinophilia. However, the meaning of this dichotomous categorization in CRS seems to be not quite clear. This review focus on the limitations in current subclassification of CRS according to the presence of NP and tissue eosinophilia and discuss other factors related to tissue remodeling and NP generation which may provide clues for the further understanding of CRS pathogenesis. PMID:28765816

  2. The LLNL High Accuracy Volume Renderer for Unstructured Data: Capabilities, Current Limits, and Potential for ASCI/VIEWS Deployment

    Energy Technology Data Exchange (ETDEWEB)

    Williams, P L; Max, N L

    2001-06-04

    This report describes a volume rendering system for unstructured data, especially finite element data, that creates images with very high accuracy. The system will currently handle meshes whose cells are either linear or quadratic tetrahedra, or meshes with mixed cell types: tetrahedra, bricks, prisms, and pyramids. The cells may have nonplanar facets. Whenever possible, exact mathematical solutions for the radiance integrals and for interpolation are used. Accurate semitransparent shaded isosurfaces may be embedded in the volume rendering. For very small cells, subpixel accumulation by splatting is used to avoid sampling error. A new exact and efficient visibility ordering algorithm is described. The most accurate images are generated in software, however, more efficient algorithms utilizing graphics hardware may also be selected. The report describes the parallelization of the system for a distributed-shared memory multiprocessor machine, and concludes by discussing the system's limits, desirable future work, and ways to extend the system so as to be compatible with projected ASCI/VIEWS architectures.

  3. Current meter components and other data from FIXED PLATFORMS from the SW Atlantic (limit-20 W) from 27 January 1986 to 01 April 1987 (NODC Accession 8800329)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter components data were collected from FIXED PLATFORMS in the SW Atlantic (limit-20 W) from 27 January 1986 to 01 April 1987. Data were collected by...

  4. Current meter components and other data from FIXED PLATFORMS from NE Pacific (limit-180) from 25 April 1984 to 01 May 1990 (NODC Accession 9100018)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter components data were collected from FIXED PLATFORMS in the NE Pacific (limit-180) from 25 April 1984 to 01 May 1990. Data were collected by the Pacific...

  5. Experiments on current-driven three-dimensional ion sound turbulence. I - Return-current limited electron beam injection. II - Wave dynamics

    Science.gov (United States)

    Stenzel, R. L.

    1978-01-01

    Pulsed electron beam injection into a weakly collisional magnetized background plasma is investigated experimentally; properties of the electron beam and background plasma, as well as the low-frequency instabilities and wave dynamics, are discussed. The current of the injected beam closes via a field-aligned return current of background electrons. Through study of the frequency and wavenumber distribution, together with the electron distribution function, the low-frequency instabilities associated with the pulsed injection are identified as ion acoustic waves driven unstable by the return current. The frequency cut-off of the instabilities predicted from renormalized plasma turbulence theory, has been verified experimentally.

  6. Approach to Recover Hydrocarbons from Currently Off-Limit Areas of the Antrim Formation, MI Using Low-Impact Technologies

    Energy Technology Data Exchange (ETDEWEB)

    James Wood; William Quinlan

    2008-09-30

    The goal of this project was to develop and execute a novel drilling and completion program in the Antrim Shale near the western shoreline of Northern Michigan. The target was the gas in the Lower Antrim Formation (Upper Devonian). Another goal was to see if drilling permits could be obtained from the Michigan DNR that would allow exploitation of reserves currently off-limits to exploration. This project met both of these goals: the DNR (Michigan Department of Natural Resources) issued permits that allow drilling the shallow subsurface for exploration and production. This project obtained drilling permits for the original demonstration well AG-A-MING 4-12 HD (API: 21-009-58153-0000) and AG-A-MING 4-12 HD1 (API: 21-009-58153-0100) as well as for similar Antrim wells in Benzie County, MI, the Colfax 3-28 HD and nearby Colfax 2-28 HD which were substituted for the AG-A-MING well. This project also developed successful techniques and strategies for producing the shallow gas. In addition to the project demonstration well over 20 wells have been drilled to date into the shallow Antrim as a result of this project's findings. Further, fracture stimulation has proven to be a vital step in improving the deliverability of wells to deem them commercial. Our initial plan was very simple; the 'J-well' design. We proposed to drill a vertical or slant well 30.48 meters (100 feet) below the glacial drift, set required casing, then angle back up to tap the resource lying between the base to the drift and the conventional vertical well. The 'J'-well design was tested at Mancelona Township in Antrim County in February of 2007 with the St. Mancelona 2-12 HD 3.

  7. Fault-current predetermination using time-limited CT secondary side measurements by the covariance-Prony method

    Energy Technology Data Exchange (ETDEWEB)

    Kamel, N.; Sankaran, P.; Venkatesh, B. [Multimedia Univ. (Malaysia)

    2004-11-01

    Protective current transformers (CTs) are integrated into electrical power systems for assessment of the health of the system. They are intended to provide a scaled-down value of the line current. During major faults, excessive fault currents with decaying DC components could flow through the primary of the CT, causing core saturation and a consequent malfunction of the protection system. This problem is addressed in the paper, and a signal-processing scheme is proposed for fast predetermination of the peak value of the steady-state AC component, instant of occurrence of fault and the time constant of the decaying direct current. Samples of the CT secondary current are collected until the onset of saturation, and are operated upon using a covariance-Prony algorithm to estimate the aforementioned critical parameters. Simulation results in support of the proposed technique are also presented. (author)

  8. An improved low-voltage ride-through performance of DFIG based wind plant using stator dynamic composite fault current limiter.

    Science.gov (United States)

    Gayen, P K; Chatterjee, D; Goswami, S K

    2016-05-01

    In this paper, an enhanced low-voltage ride-through (LVRT) performance of a grid connected doubly fed induction generator (DFIG) has been presented with the usage of stator dynamic composite fault current limiter (SDCFCL). This protection circuit comprises of a suitable series resistor-inductor combination and parallel bidirectional semiconductor switch. The SDCFCL facilitates double benefits such as reduction of rotor induced open circuit voltage due to increased value of stator total inductance and concurrent increase of rotor impedance. Both effects will limit rotor circuit over current and over voltage situation more secured way in comparison to the conventional scheme like the dynamic rotor current limiter (RCL) during any type of fault situation. The proposed concept is validated through the simulation study of the grid integrated 2.0MW DFIG.

  9. Development of resistive type superconducting fault current limiter using oxide superconductor; Sankabutsu chodendotai wo mochiita teikogata chodendo genryuki no kaihatsu -muyudo sorenoido koiru no shisaku shiken kekka

    Energy Technology Data Exchange (ETDEWEB)

    Yoneda, E.; Shimada, M.; Nomura, S. [Toshiba Corp., Tokyo (Japan); Okuma, T.; Sato, Y.; Iwata, Y. [Tokyo Electric Power Co., Inc., Tokyo (Japan)

    1999-11-10

    We have advanced the development of resistive superconductivity current limiter using the normal transition of the superconductor until now, and it has produced and tested 6.6kV/1kA single-phase current limiter using the metal system superconductor experimentally. As a result of these evaluations, in turning to the practical application of that the oxide superconductor was used from the metal system superconductor from the viewpoint of wire rod performance, refrigerating machine, insulation performance, it reached the advantageous conclusion. Here, it reports the result that it produced the mischievous prank non-induction coil model experimentally in the mind and tested coil resistance type current-limiting element using the oxide superconductor. (NEDO)

  10. Current limitations in super-resolution fluorescence microscopy for biological specimens: How deep can we go from the cover glass?

    Science.gov (United States)

    Okada, Yasushi

    2017-04-01

    Diffraction limit of resolution has been one of the biggest limitations in the optical microscopy. Super-resolution fluorescence microscopy has enabled us to break this limit. However, for the observations of real biological specimens, especially for the imaging of tissues or whole body, the target structures of interest are often embedded deep inside the specimen. Here, we would present our results to extend the target of the super-resolution microscopy deeper into the cells. Confocal microscope optics work effectively to minimize the effect by the aberrations by the cellular components, but at the expense of the signal intensities. Spherical aberrations by the refractive index mismatch between the cellular environment and the immersion liquid can be much larger, but can be reduced by adjusting the correction collar at the objective lens.

  11. buffer Layer Growth, the Thickness Dependence of Jc in Coated Conductors, Local Identification of Current Limiting Mechanisms and Participation in the Wire Development Group

    Energy Technology Data Exchange (ETDEWEB)

    Larbalestier, David; Hellstron, Eric; Abraimov, Dmytro

    2011-12-17

    The primary thrusts of our work were to provide critical understanding of how best to enhance the current-carrying capacity of coated conductors. These include the deconstruction of Jc as a function of fim thickness, the growth of in situ films incorporating strong pinning centers and the use of a suite of position-sensitive tools that enable location and analysis of key areas where current-limiting occurs.

  12. Reviews on Current-limiting Protection Based on PTC Materials%基于PTC材料的限流保护研究现状

    Institute of Scientific and Technical Information of China (English)

    惠飞飞; 杨锋

    2015-01-01

    Aimed at the increasing of the short circuit current, the current limiting is an effective way to achieve the short-circuit protection. To adopt PTC components in the current-limiting protection is a new method in this area, which not only can be both recoverable and reusable, but also has the great potential of application in the area of the large current breaker. This paper mainly summarizes and compares existing methods for current-limiting protection. What's more, it systematically analyzes the problems in the research on PTC and listed on the types and applications of those PTC in being. More importantly, detailed analysis is made in this paper on the feasibility for the solution related to PTC's withstand voltage as well as its large current shock. Finally, the full text and get the drafting solution for the PTC's application in current limit is summarized.%短路电流不断增大,采用限流的方式进行短路保护是一种有效的保护方式.使用PTC元件进行限流保护是一种新型的保护方式,具有可恢复性和可重复使用的特点,且对于大电流的分断具有很大的应用潜力.该文对现有限流保护技术进行总结与比对,对PTC研究存在问题进行系统分析,阐述罗列现有PTC种类以及适用用途,并对其耐压大电流冲击方案进行可行性分析.最后对其全文进行总结,给出限流应用PTC拟解决方案.

  13. Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current

    NARCIS (Netherlands)

    Assmy, P.; Smetacek, V.; Klaas, C.; Henjes, J.; Strass, V.H.; Arrieta, J.M.; Bathmann, U.; Cisewski, B.; Fuchs, N.; Herndl, G.J.

    2013-01-01

    Diatoms of the iron-replete continental margins and North Atlantic are key exporters of organic carbon. In contrast, diatoms of the iron-limited Antarctic Circumpolar Current sequester silicon, but comparatively little carbon, in the underlying deep ocean and sediments. Because the Southern Ocean is

  14. A Dual-Mode Step-up DC/DC Converter IC with Current-Limiting and EMI Reduction Techniques

    Institute of Scientific and Technical Information of China (English)

    Wan-Rone Liou; Chun-Ting Kuo; Mei-Ling Yeh; Ping-Hsing Chen; Marynelle L. Z. Rosales

    2008-01-01

    This paper presents a novel dual-mode step-up (boost) DC/DC converter. Pulse-frequency modulation (PFM) is used to improve the efficiency at light load. This converter can operate between pulse-width modulation (PWM) and pulse-frequency modulation. The converter will operate in PFM mode at light load and in PWM mode at heavy load. The maximum conversion efficiency of this converter is 96%. The conversion efficiency is greatly improved when load current is below 100 mA. Additionally, a soft-start circuit and a variable-sawtooth frequency circuit are proposed in this paper. The former is used to avoid the large switching current at the start up of the converter and the latter is utilized to reduce the EMI of the converter.

  15. Current limitations and a path forward to improve testing for the environmental assessment of endocrine active substances

    DEFF Research Database (Denmark)

    Coady, Katherine K.; Biever, Ronald C.; Denslow, Nancy D.

    issue of significant concern to for current EACS screening/testing programs involves resources in regard such as to cost, time, trained personnel, and animal use. This is especially problematic when considering the number of chemicals that some regulatory authorities need to assess. One way to address......, statistical power to detect biologically significant adverse effects, delivery and analytical measurement of test substances, availability of technical expertise, and study interpretation, including linking mechanistic and apical effects. Some of these areas can be addressed by the lessons learned and best...... screening/testing. Finally, a number of recommendations are provided for longer term research to address areas of uncertainty, including identifying potentially sensitive species for which test methods currently do not exist (e.g., invertebrates) and key endocrine pathways in addition to estrogen, androgen...

  16. Nanofabrication of Arrays of Silicon Field Emitters with Vertical Silicon Nanowire Current Limiters and Self-Aligned Gates

    Science.gov (United States)

    2016-08-19

    Akinwande Department of Electrical Engineering and Computer Science and Microsystems Technology Laboratories, Massachusetts Institute of Technology ...Cambridge, MA 02139, USA E-mail: guerrera@alum.mit.edu Received 16 September 2015, revised 2 December 2015 Accepted for publication 11 January 2016...series with the tip. Using the current voltage characteristics and with the aid of numerical device models , we estimated the tip radius of our field

  17. Analysis of SFCL’s in DC System with Renewable Energy Sources

    Directory of Open Access Journals (Sweden)

    S. Mohanram

    2015-12-01

    Full Text Available Superconducting fault-current limiters (SFCLs have been the subject of research and development for many years and offer an attractive solution to the problem of rising fault levels in electrical distribution systems. SFCLs can greatly reduce fault currents and the damage at the point of fault, and help improve the stability of a power system. Superconducting fault-current limiters (SFCL provide a new efficient approach to the reliable handling of such faults.(SCFLs can be used for various nominal voltages and currents, and can be adapted to particular limiting characteristics in case of short circuits. In this project, dc resistive type superconducting fault current limiter (SFCL is presented. This SFCL is designed for the HVDC system. Uniform current and voltage sharing among the SFCL modules can be observed through contact resistance tests, dc flow-through tests, and ac flow-through tests. Results of tests show that each limiting module has good uniformity in higher current system. The proposed concept can be implemented using renewable energy sources. The results are presented by using Matlab / simulink platform.

  18. Assaying embryotoxicity in the test tube: current limitations of the embryonic stem cell test (EST) challenging its applicability domain.

    Science.gov (United States)

    Riebeling, Christian; Hayess, Katrin; Peters, Annelieke K; Steemans, Margino; Spielmann, Horst; Luch, Andreas; Seiler, Andrea E M

    2012-05-01

    Testing for embryotoxicity in vitro is an attractive alternative to animal experimentation. The embryonic stem cell test (EST) is such a method, and it has been formally validated by the European Centre for the Validation of Alternative Methods. A number of recent studies have underscored the potential of this method. However, the EST performed well below the 78% accuracy expected from the validation study using a new set of chemicals and pharmaceutical compounds, and also of toxicity criteria, tested to enlarge the database of the validated EST as part of the Work Package III of the ReProTect Project funded within the 6th Framework Programme of the European Union. To assess the performance and applicability domain of the EST we present a detailed review of the substances and their effects in the EST being nitrofen, ochratoxin A, D-penicillamine, methylazoxymethanol, lovastatin, papaverine, warfarin, β-aminopropionitrile, dinoseb, furosemide, doxylamine, pravastatin, and metoclopramide. By delineation of the molecular mechanisms of the substances we identify six categories of reasons for misclassifications. Some of these limitations might also affect other in vitro methods assessing embryotoxicity. Substances that fall into these categories need to be included in future validation sets and in validation guidelines for embryotoxicity testing. Most importantly, we suggest conceivable improvements and additions to the EST which will resolve most of the limitations.

  19. [Evaluation of scientific production in different subareas of Public Health: limits of the current model and contributions to the debate].

    Science.gov (United States)

    Iriart, Jorge Alberto Bernstein; Deslandes, Suely Ferreira; Martin, Denise; Camargo Jr, Kenneth Rochel de; Carvalho, Marilia Sá; Coeli, Cláudia Medina

    2015-10-01

    The aim of this study was to discuss the limits of the quantitative evaluation model for scientific production in Public Health. An analysis of the scientific production of professors from the various subareas of Public Health was performed for 2010-2012. Distributions of the mean annual score for professors were compared according to subareas. The study estimated the likelihood that 60% of the professors in the graduate studies programs scored P50 (Very Good) or higher in their area. Professors of Epidemiology showed a significantly higher median annual score. Graduate studies programs whose faculty included at least 60% of Epidemiology professors and fewer than 10% from the subarea Social and Human Sciences in Health were significantly more likely to achieve a "Very Good" classification. The observed inequalities in scientific production between different subareas of Public Health point to the need to rethink their evaluation in order to avoid reproducing iniquities that have harmful consequences for the field's diversity.

  20. Barrier inhomogeneities limited current and 1/f noise transport in GaN based nanoscale Schottky barrier diodes

    Science.gov (United States)

    Kumar, Ashutosh; Heilmann, M.; Latzel, Michael; Kapoor, Raman; Sharma, Intu; Göbelt, M.; Christiansen, Silke H.; Kumar, Vikram; Singh, Rajendra

    2016-01-01

    The electrical behaviour of Schottky barrier diodes realized on vertically standing individual GaN nanorods and array of nanorods is investigated. The Schottky diodes on individual nanorod show highest barrier height in comparison with large area diodes on nanorods array and epitaxial film which is in contrast with previously published work. The discrepancy between the electrical behaviour of nanoscale Schottky diodes and large area diodes is explained using cathodoluminescence measurements, surface potential analysis using Kelvin probe force microscopy and 1ow frequency noise measurements. The noise measurements on large area diodes on nanorods array and epitaxial film suggest the presence of barrier inhomogeneities at the metal/semiconductor interface which deviate the noise spectra from Lorentzian to 1/f type. These barrier inhomogeneities in large area diodes resulted in reduced barrier height whereas due to the limited role of barrier inhomogeneities in individual nanorod based Schottky diode, a higher barrier height is obtained. PMID:27282258

  1. Barrier inhomogeneities limited current and 1/f noise transport in GaN based nanoscale Schottky barrier diodes.

    Science.gov (United States)

    Kumar, Ashutosh; Heilmann, M; Latzel, Michael; Kapoor, Raman; Sharma, Intu; Göbelt, M; Christiansen, Silke H; Kumar, Vikram; Singh, Rajendra

    2016-01-01

    The electrical behaviour of Schottky barrier diodes realized on vertically standing individual GaN nanorods and array of nanorods is investigated. The Schottky diodes on individual nanorod show highest barrier height in comparison with large area diodes on nanorods array and epitaxial film which is in contrast with previously published work. The discrepancy between the electrical behaviour of nanoscale Schottky diodes and large area diodes is explained using cathodoluminescence measurements, surface potential analysis using Kelvin probe force microscopy and 1ow frequency noise measurements. The noise measurements on large area diodes on nanorods array and epitaxial film suggest the presence of barrier inhomogeneities at the metal/semiconductor interface which deviate the noise spectra from Lorentzian to 1/f type. These barrier inhomogeneities in large area diodes resulted in reduced barrier height whereas due to the limited role of barrier inhomogeneities in individual nanorod based Schottky diode, a higher barrier height is obtained.

  2. Using of explosive technologies for development of a compact current-limiting device for operation on 110 kV class systems

    Science.gov (United States)

    Shurupov, A. V.; Shurupov, M. A.; Kozlov, A. A.; Kotov, A. V.

    2016-11-01

    This paper considers the possibility of creating on new physical principles a highspeed current-limiting device (CLD) for the networks with voltage of 110 kV, namely, on the basis of the explosive switching elements. The device is designed to limit the steady short-circuit current to acceptable values for the time does not exceed 3 ms at electric power facilities. The paper presents an analysis of the electrical circuit of CLD. The main features of the scheme are: a new high-speed switching element with high regenerating voltage; fusible switching element that enables to limit the overvoltage after sudden breakage of network of the explosive switch; non-inductive resistor with a high heat capacity and a special reactor with operating time less than 1 s. We analyzed the work of the CLD with help of special software PSPICE, which is based on the equivalent circuit of single-phase short circuit to ground in 110 kV network. Analysis of the equivalent circuit operation CLD shows its efficiency and determines the CLD as a perspective direction of the current-limiting devices of new generation.

  3. Current limitations and a path forward to improve testing for the environmental assessment of endocrine active substances

    DEFF Research Database (Denmark)

    Coady, Katherine K.; Biever, Ronald C.; Denslow, Nancy D.

    issue of significant concern to for current EACS screening/testing programs involves resources in regard such as to cost, time, trained personnel, and animal use. This is especially problematic when considering the number of chemicals that some regulatory authorities need to assess. One way to address......To assess the hazards and risks of possible endocrine active chemicals (EACs) there is a need for robust, validated test methods that detect perturbation of endocrine pathways of concern and provide insights reliable information as to assess to potential adverse effects on apical endpoints. One...... practices developed through recent experiences conducting EAC screening/testing. Additionally, the collective assessment of EAC screening and testing data (e.g. compilation of historical control data) can be leveraged to refine test designs and performance criteria to maximize the power and utility of EAC...

  4. A Dual-Mode Step-up DC/DC Converter IC with Current-Limiting and EMI Reduction Techniques

    Institute of Scientific and Technical Information of China (English)

    Wan-Rone Liou; Chun-Ting Kuo; Mei-Ling Yeh; Ping-Hsing Chen; Marynelle L. Z. Rosales

    2008-01-01

    This paper presents a novel dual-modestep-up (boost) DC/DC converter. Pulse-frequencymodulation (PFM) is used to improve the efficiency atlight load. This converter can operate betweenpulse-width modulation (PWM) and pulse-frequencymodulation. The converter will operate in PFM mode atlight load and in PWM mode at heavy load. Themaximum conversion efficiency of this converter is 96%.The conversion efficiency is greatly improved when loadcurrent is below 100 mA. Additionally, a soft-startcircuit and a variable-sawtooth frequency circuit areproposed in this paper. The former is used to avoid thelarge switching current at the start up of the converterand the latter is utilized to reduce the EMI of theconverter.

  5. Learned EEG-based regulation of motor-related brain oscillations during application of transcranial electric currents: feasibility and limitations

    Directory of Open Access Journals (Sweden)

    Surjo R Soekadar

    2014-03-01

    Full Text Available Objective: Transcranial direct current stimulation (tDCS improves motor learning and can influence emotional processing or attention. However, it remained unclear whether learned electroencephalography (EEG-based brain-machine interface (BMI control during tDCS is feasible and how application of transcranial electric currents during BMI control would interfere with feature-extraction of physiological brain signals. Here we tested this combination and evaluated stimulation-dependent artifacts across different EEG frequencies and stability of motor imagery-based BMI control. Approach: Ten healthy volunteers were invited to two BMI-sessions, each comprising two 60-trial blocks. During the trials, modulation of mu-rhythms (8-15Hz associated with motor imagery recorded over C4 was translated into online cursor movements on a computer screen. During block 2, either sham (session A or anodal tDCS (session B was applied at 1mA with the stimulation electrode placed 1cm anterior of C4. Main results: tDCS was associated with a significant signal power increase in the lower frequencies most evident in the signal spectrum of the EEG channel closest to the stimulation electrode. Stimulation-dependent signal power increase exhibited a decay of 12dB per decade, leaving frequencies above 9Hz unaffected. Analysis of BMI control performance did not indicate a difference between blocks and tDCS conditions. Conclusion: Application of tDCS during learned EEG-based self-regulation of brain oscillations above 9Hz is feasible and safe, and might improve applicability of BMI systems in patient populations.

  6. Limits for the graphene on ferroelectric domain wall p-n-junction rectifier for different regimes of current

    Science.gov (United States)

    Strikha, Maksym V.; Morozovska, Anna N.

    2016-12-01

    Here, we present the theory of the conductivity of a pn junction (pnJ) in a graphene channel, placed on a ferroelectric substrate, caused by the ferroelectric domain wall for the case of the arbitrary current regime: from ballistic to diffusive one. We calculated the ratio of the pnJ conductions for opposite polarities of voltages, applied to source and drain electrodes of the channel, G+to t a l /G-to t a l , as a function of graphene channel length L, electron mean free path λ, and ferroelectric substrate permittivity ɛ33f . We have demonstrated that the small values of G+to t a l /G-to t a l (0.1 and smaller), which correspond to the efficient graphene pnJ based rectifier, can be obtained for the ferroelectrics with high ɛ33f≫100 and for the ratios of L/λ ˜ 1 or smaller. However, for ferroelectrics with extremely high ɛ33f (relaxor or PbZrxTi1-xO3 with the composition x near the morphotropic phase boundary x = 0.52), the ratio G+to t a l /G-to t a l can be essentially smaller than unity for the case of a pronounced diffusive regime of current as well. This makes the ferroelectric substrates with high permittivity excellent candidates for the fabrication of new generation of rectifiers based on the graphene pnJ. The temperature effect on the G+to t a l /G-to t a l ratio was studied within the Landau-Ginzburg-Devonshire approach. We have demonstrated that the rectifying properties of the graphene pnJ become better in the vicinity of Curie temperature. However, for the temperatures higher than the Curie temperature, the rectifying effect vanishes due to the ferroelectric polarization disappearance.

  7. Non-invasive brain stimulation for the treatment of brain diseases in childhood and adolescence: state of the art, current limits and future challenges

    Directory of Open Access Journals (Sweden)

    Carmelo Mario Vicario

    2013-11-01

    Full Text Available In the last decades interest in application of non-invasive brain stimulation for enhancing neural functions is growing continuously. However, the use of such techniques in pediatric populations remains rather limited and mainly confined to the treatment of severe neurological and psychiatric diseases. In this article we provide a complete review of non-invasive brain stimulation studies conducted in pediatric populations. We also provide a brief discussion about the current limitations and future directions in a field of research still very young and full of issues to be explored.

  8. Feasibility analysis of a novel hybrid-type superconducting circuit breaker in multi-terminal HVDC networks

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Umer Amir [Hanyang University, Sa-3dong, Sangrok-gu, Ansan 426-791 (Korea, Republic of); National University of Sciences and Technology, PNEC Campus, Habib Rehmatullah Road, Karachi (Pakistan); Lee, Jong-Geon; Seo, In-Jin [Hanyang University, Sa-3dong, Sangrok-gu, Ansan 426-791 (Korea, Republic of); Amir, Faisal [National University of Sciences and Technology, PNEC Campus, Habib Rehmatullah Road, Karachi (Pakistan); Lee, Bang-Wook, E-mail: bangwook@hanyang.ac.kr [Hanyang University, Sa-3dong, Sangrok-gu, Ansan 426-791 (Korea, Republic of)

    2015-11-15

    Highlights: • A novel hybrid-type superconducting circuit breaker (SDCCB) is proposed. • SDCCB has SFCL located in the main current path to limit the fault current until the final trip signal. • SFCL in SDCCB suppressed the fast rising DC fault current for a predefined time. • SFCL significantly reduced the DC current breaking stress on SDCCB components. • SDCCB isolated the HVDC faulty line in three, four, and five converter stations MTDC. - Abstract: Voltage source converter-based HVDC systems (VSC-HVDC) are a better alternative than conventional thyristor-based HVDC systems, especially for developing multi-terminal HVDC systems (MTDC). However, one of the key obstacles in developing MTDC is the absence of an adequate protection system that can quickly detect faults, locate the faulty line and trip the HVDC circuit breakers (DCCBs) to interrupt the DC fault current. In this paper, a novel hybrid-type superconducting circuit breaker (SDCCB) is proposed and feasibility analyses of its application in MTDC are presented. The SDCCB has a superconducting fault current limiter (SFCL) located in the main current path to limit fault currents until the final trip signal is received. After the trip signal the IGBT located in the main line commutates the current into a parallel line where DC current is forced to zero by the combination of IGBTs and surge arresters. Fault simulations for three-, four- and five-terminal MTDC were performed and SDCCB performance was evaluated in these MTDC. Passive current limitation by SFCL caused a significant reduction of fault current interruption stress in the SDCCB. It was observed that the DC current could change direction in MTDC after a fault and the SDCCB was modified to break the DC current in both the forward and reverse directions. The simulation results suggest that the proposed SDCCB could successfully suppress the DC fault current, cause a timely interruption, and isolate the faulty HVDC line in MTDC.

  9. Constraints on the formation of double neutron stars from the observed eccentricities and current limits on merger rates

    CERN Document Server

    Chruslinska, Martyna; Bulik, Tomasz; Gladysz, Wojciech

    2016-01-01

    We employ population synthesis method to model the double neutron star (DNS) population and test various possibilities on natal kick velocities gained by neutron stars after their formation. We first choose natal kicks after standard core collapse SN from a Maxwellian distribution with velocity dispersion of sigma=265 km/s as proposed by Hobbs et al. (2005) and then modify this distribution by changing the velocity dispersion towards smaller and larger kick values. We also take into account the possibility of NS formation through electron capture supernova. In this case we test two scenarios: zero natal kick or small natal kick, drawn from Maxwellian distribution with sigma = 26.5 km/s. We calculate the present-day orbital parameters of binaries and compare the resulting eccentricities with those known for observed DNSs. As an additional test we calculate Galactic merger rates for our model populations and confront them with observational limits. We do not find any model unequivocally consistent with both obs...

  10. Constraints on the Formation of Double Neutron Stars from the Observed Eccentricities and Current Limits on Merger Rates

    Science.gov (United States)

    Chruslinska, M.; Belczynski, K.; Bulik, T.; Gladysz, W.

    2017-03-01

    We employ population synthesis method to model the double neutron star (DNS) population and test various possibilities on natal kick velocities gained by neutron stars after their formation. We first choose natal kicks after standard core collapse supernovae (CCSN) from a Maxwellian distribution with velocity dispersion of σ = 265 km/s as proposed by Hobbs and then modify this distribution by changing σ toward smaller and larger kick values. We also take into account the possibility of NS formation through electron capture supernova. In this case we test two scenarios: zero natal kick or small natal kick, drawn from Maxwellian distribution with σ = 26.5 km/s. We calculate the present-day orbital parameters of binaries and compare the resulting eccentricities with those known for observed DNSs. As an additional test we calculate Galactic merger rates for our model populations and confront them with observational limits. We do not find any model unequivocally consistent with both observational constraints simultaneously. The models with low kicks after CCSN for binaries with the second NS forming through core collapse SN are marginally consistent with the observations. This means that either 14 observed DNSs are not representative of the intrinsic Galactic population, or that our modeling of DNS formation needs revision.

  11. Evaluation of critical current density and residual resistance ratio limits in powder in tube Nb3Sn conductors

    CERN Document Server

    Segal, Christopher; Sung, Zu Hawn; Lee, Peter J; Sailer, Bernd; Thoener, Manfred; Schlenga, Klaud; Ballarino, Amalia; Bottura, Luca; Bordini, Bernardo; Scheuerlein, Christian; Larnalestier, David C

    2016-01-01

    High critical current density ( Jc) Nb3Sn A15 multifilamentary wires require a large volume fraction of small grain (SG), superconducting A15 phase, as well as Cu stabilizer with high Residual Resistance Ratio (RRR) to provide electromagnetic stabilization and protection. In powder-in-tube (PIT) wires the unreacted Nb7.5 wt%Ta outer layer of the tubular filaments acts as a diffusion barrier and protects the interfilamentary Cu stabilizer from Sn contamination. A high RRR requirement generally imposes a restricted A15 reaction heat treatment to prevent localized full reaction of the filament that could allow Sn to reach the Cu. In this study we investigate recent high quality PIT wires that achieve a Jc (12 T, 4.2 K) up to ∼2500 A mm−2 and find that the minimum diffusion barrier thickness decreases as the filament aspect ratio increases from ∼1 in the inner rings of filaments to 1.3 in the outer filament rings. We found that just 2–3 diffusion barrier breaches can degrade RRR from 300 to 150 or less. U...

  12. Evaluation of critical current density and residual resistance ratio limits in powder in tube Nb3Sn conductors

    CERN Document Server

    Segal, Christopher; Sung, Zu Hawn; Lee, Peter J; Sailer, Bernd; Thoener, Manfred; Schlenga, Klaud; Ballarino, Amalia; Bottura, Luca; Bordini, Bernardo; Scheuerlein, Christian; Larnalestier, David C

    2016-01-01

    High critical current density ( Jc) Nb3Sn A15 multifilamentary wires require a large volume fraction of small grain (SG), superconducting A15 phase, as well as Cu stabilizer with high Residual Resistance Ratio (RRR) to provide electromagnetic stabilization and protection. In powder-in-tube (PIT) wires the unreacted Nb7.5 wt%Ta outer layer of the tubular filaments acts as a diffusion barrier and protects the interfilamentary Cu stabilizer from Sn contamination. A high RRR requirement generally imposes a restricted A15 reaction heat treatment to prevent localized full reaction of the filament that could allow Sn to reach the Cu. In this study we investigate recent high quality PIT wires that achieve a Jc (12 T, 4.2 K) up to ∼2500 A mm−2 and find that the minimum diffusion barrier thickness decreases as the filament aspect ratio increases from ∼1 in the inner rings of filaments to 1.3 in the outer filament rings. We found that just 2–3 diffusion barrier breaches can degrade RRR from 300 to 150 or less. U...

  13. Cut-off characterisation of energy spectra of bright fermi sources: Current instrument limits and future possibilities

    Science.gov (United States)

    Romoli, C.; Taylor, A. M.; Aharonian, F.

    2017-02-01

    In this paper some of the brightest GeV sources observed by the Fermi-LAT were analysed, focusing on their spectral cut-off region. The sources chosen for this investigation were the brightest blazar flares of 3C 454.3 and 3C 279 and the Vela pulsar with a reanalysis with the latest Fermi-LAT software. For the study of the spectral cut-off we first explored the Vela pulsar spectrum, whose statistics in the time interval of the 3FGL catalog allowed strong constraints to be obtained on the parameters. We subsequently performed a new analysis of the flaring blazar SEDs. For these sources we obtained constraints on the cut-off parameters under the assumption that their underlying spectral distribution is described by a power-law with a stretched exponential cut-off. We then highlighted the significant potential improvements on such constraints by observations with next generation ground based Cherenkov telescopes, represented in our study by the Cherenkov Telescope Array (CTA). Adopting currently available simulations for this future observatory, we demonstrate the considerable improvement in cut-off constraints achievable by observations with this new instrument when compared with that achievable by satellite observations.

  14. Cut-off Characterisation of Energy Spectra of Bright Fermi Sources: Current instrument limits and future possibilities

    CERN Document Server

    Romoli, C; Aharonian, F

    2016-01-01

    In this paper some of the brightest GeV sources observed by the Fermi-LAT were analysed, focusing on their spectral cut-off region. The sources chosen for this investigation were the brightest blazar flares of 3C 454.3 and 3C 279 and the Vela pulsar using catalogue data and reanalysis with the latest Fermi-LAT software. For the study the spectral cut-off we first explored the Vela pulsar spectrum, whose statistics in the 3FGL catalog allowed strong constraints to be obtained on the parameters. We subsequently performed a new analysis of the flaring blazar SEDs. For these sources we obtained constraints on the cut-off parameters under the assumption that their underlying spectral distribution is described by a power-law with a stretched exponential cut-off. We then highlighted the significant potential improvements on such constraints by observations with next generation ground based Cherenkov telescopes, represented in our study by the Cherenkov Telescope Array (CTA). Adopting currently available simulations ...

  15. Exploring the Physics Limitations of Compact High Gradient Accelerating Structures Simulations of the Electron Current Spectrometer Setup in Geant4

    CERN Document Server

    Van Vliet, Philine Julia

    2017-01-01

    The high field gradient of 100 MV/m that will be applied to the accelerator cavities of the Compact Linear Collider (CLIC), gives rise to the problem of RF breakdowns. The field collapses and a plasma of electrons and ions is being formed in the cavity, preventing the RF field from penetrating the cavity. Electrons in the plasma are being accelerated and ejected out, resulting in a breakdown current up to a few Amp`eres, measured outside the cavities. These breakdowns lead to luminosity loss, so reducing their amount is of great importance. For this, a better understanding of the physics behind RF breakdowns is needed. To study these breakdowns, the XBox 2 test facility has a spectrometer setup installed after the RF cavity that is being conditioned. For this report, a simulation of this spectrometer setup has been made using Geant4. Once a detailed simulation of the RF field and cavity has been made, it can be connected to this simulation of the spectrometer setup and used to recreate the data that has b...

  16. Molecular and cellular approaches for the detection of protein-protein interactions: latest techniques and current limitations.

    Science.gov (United States)

    Lalonde, Sylvie; Ehrhardt, David W; Loqué, Dominique; Chen, Jin; Rhee, Seung Y; Frommer, Wolf B

    2008-02-01

    Homotypic and heterotypic protein interactions are crucial for all levels of cellular function, including architecture, regulation, metabolism, and signaling. Therefore, protein interaction maps represent essential components of post-genomic toolkits needed for understanding biological processes at a systems level. Over the past decade, a wide variety of methods have been developed to detect, analyze, and quantify protein interactions, including surface plasmon resonance spectroscopy, NMR, yeast two-hybrid screens, peptide tagging combined with mass spectrometry and fluorescence-based technologies. Fluorescence techniques range from co-localization of tags, which may be limited by the optical resolution of the microscope, to fluorescence resonance energy transfer-based methods that have molecular resolution and can also report on the dynamics and localization of the interactions within a cell. Proteins interact via highly evolved complementary surfaces with affinities that can vary over many orders of magnitude. Some of the techniques described in this review, such as surface plasmon resonance, provide detailed information on physical properties of these interactions, while others, such as two-hybrid techniques and mass spectrometry, are amenable to high-throughput analysis using robotics. In addition to providing an overview of these methods, this review emphasizes techniques that can be applied to determine interactions involving membrane proteins, including the split ubiquitin system and fluorescence-based technologies for characterizing hits obtained with high-throughput approaches. Mass spectrometry-based methods are covered by a review by Miernyk and Thelen (2008; this issue, pp. 597-609). In addition, we discuss the use of interaction data to construct interaction networks and as the basis for the exciting possibility of using to predict interaction surfaces.

  17. Evaluation of critical current density and residual resistance ratio limits in powder in tube Nb3Sn conductors

    Science.gov (United States)

    Segal, Christopher; Tarantini, Chiara; Hawn Sung, Zu; Lee, Peter J.; Sailer, Bernd; Thoener, Manfred; Schlenga, Klaus; Ballarino, Amalia; Bottura, Luca; Bordini, Bernardo; Scheuerlein, Christian; Larbalestier, David C.

    2016-08-01

    High critical current density (J c) Nb3Sn A15 multifilamentary wires require a large volume fraction of small grain (SG), superconducting A15 phase, as well as Cu stabilizer with high Residual Resistance Ratio (RRR) to provide electromagnetic stabilization and protection. In powder-in-tube (PIT) wires the unreacted Nb7.5 wt%Ta outer layer of the tubular filaments acts as a diffusion barrier and protects the interfilamentary Cu stabilizer from Sn contamination. A high RRR requirement generally imposes a restricted A15 reaction heat treatment to prevent localized full reaction of the filament that could allow Sn to reach the Cu. In this study we investigate recent high quality PIT wires that achieve a J c (12 T, 4.2 K) up to ˜2500 A mm-2 and find that the minimum diffusion barrier thickness decreases as the filament aspect ratio increases from ˜1 in the inner rings of filaments to 1.3 in the outer filament rings. We found that just 2-3 diffusion barrier breaches can degrade RRR from 300 to 150 or less. Using progressive etching of the Cu we also found that the RRR degradation is localized near the external filaments where deformation is highest. Consequently minimizing filament distortion during strand fabrication is important for reducing RRR degradation. The additional challenge of developing the highest possible J c must be addressed by forming the maximum fraction of high J c SG A15 and minimizing low J c large-grain (LG) A15 morphologies. In one wire we found that 15% of the filaments had a significantly enhanced SG/LG A15 ratio and no residual A15 in the core, a feature that opens a path to substantial J c improvement.

  18. 自收缩效应型液态金属限流器限流特性影响因素的研究%Study of Influence Factors on Current Limiting Characteristics of Self Pinch Effect Type Liquid Metal Current Limiter

    Institute of Scientific and Technical Information of China (English)

    刘懿莹; 吴翊; 荣命哲; 何海龙; 李阳; 刘宏

    2012-01-01

    The liquid metal current limiter(LMCL) based on self pinch effect has a good application prospect with the merits of self detection,self-healing property after fault exclusion,the environment friendly medium,simple design and small volume.In this paper,the influence factors on current limiting characteristics of LMCL was experimental investigated by measuring the circuit current and the arc voltage of LMCL under different conditions during the current limiting process,which provided reference for optimum design of LMCL structure.The experimental results indicate that the current limiting effect is improved with the reduction of pre arcing time and the increase of arc voltage,and the pre arcing time and arc voltage are influenced by the prospective short current and structure parameters,during the experiment.It was found that the arc pressure can adversely affect the current limiting characteristics under high current,so a structure with pressure release space was proposed to solve this problem;and the current limiting effect was improved effectively.%基于自收缩效应的液态金属限流器(liquid metal current limiter,LMCL)有自动检测限流、故障排除后可自恢复、填充介质对环境友好、结构简单以及体积小的独特优点,具有良好的应用前景。通过测量不同情况下限流过程回路电流以及LMCL的电弧电压,实验研究了LMCL限流特性的影响因素,为LMCL结构的优化设计提供参考依据。实验结果表明:LMCL的限流效果随着弧前时间的缩短以及电弧电压的上升而愈加明显,弧前时间和电弧电压受预期短路电流和LMCL结构参数的影响;同时实验过程中发现,大电流下电弧压力对LMCL限流性能会产生不利的影响,为解决此问题,提出了一种带有压力释放功能的限流器结构,可以有效地改善限流效果。

  19. A Limiting Current Oxygen Sensor Based on LSGM as a Solid Electrolyte and LSGMN ( N = Fe, Co) as a Dense Diffusion Barrier

    Science.gov (United States)

    Liu, Tao; Gao, Xiang; He, Bei-Gang; Yu, Jing-Kun

    2016-07-01

    The La0.8Sr0.2(Ga1- x Co x )0.8Mg0.2O3- δ (LSGMC x = 0.05, 0.1, 0.15, 0.2, 0.25) and La0.8Sr0.2(Ga1- x Fe x )0.8Mg0.2O3- δ (LSGMF x = 0.1, 0.2, 0.3) samples were prepared by solid-state reaction. The structure, conductivity, thermal expansion behavior, and chemical compatibility were studied by XRD, dilatometry, and four-terminal method. A limiting current oxygen sensor was prepared with La0.8Sr0.2Ga0.83Mg0.17O2.815 as a solid electrolyte and La0.8Sr0.2(Ga0.75Co0.25)0.8Mg0.2O3- δ as a dense diffusion barrier. The oxygen-sensitive characteristic was measured at different oxygen concentrations. The results show that the phase structure of samples is cubic, except La0.8Sr0.2(Ga0.75Co0.25)0.8Mg0.2O3- δ , which has a hexagonal structure. The change in activation energy for electrical conductivity and the increase in thermal expansion coefficient are confirmed to correlate with an increasing concentration of oxygen vacancies. The limiting current oxygen sensor exhibits a good limiting current platform and the limiting current depends linearly on the oxygen concentration: I L(mA) = 12.8519 + 2.2667 x_{{{O}_{{2}} }} (mol%, 0 < x_{{{{O}}_{ 2} }} < 3.31) at 750 °C, I L(mA) = 14.3222 + 3.5180 x_{{{O}_{{2}} }} (mol%, 0 < x_{{{{O}}_{ 2} }} < 4.16) at 800 °C, and I L(mA) = 15.2872 + 5.0269x_{{{O}_{{2}} }}(mol%, 0 < x_{{{{O}}_{ 2} }} < 4.12) at 850 °C. The sensor has the best sensitivity at 850 °C. As the oxygen concentration increases, the interface resistance of the sensor decreases at 850 °C.

  20. 限流式动态电压恢复器及其参数设计%Dynamic voltage restorer with current limiting function and its parameter design

    Institute of Scientific and Technical Information of China (English)

    唐君华; 涂春鸣; 姜飞; 刘子维; 郭成; 帅智康

    2015-01-01

    为优化电网正常运行时的电能质量,针对电力系统短路故障问题,提出了一种限流式动态电压恢复器(Dynamic voltage restorer with fault current limiting, DVR-FCL)拓扑结构。以限流阻抗值为目标函数,考虑直流侧电压整定的参数设计,给出了 DVR-FCL 的直流侧电压、输出滤波器、串联变压器参数、串联变流器、直流侧电容的整定方法。利用PSCAD/EMTDC仿真软件验证了DVR-FCL对电压跌落及短路故障的动作特性。结果表明,所提拓扑结构和参数设计方法正确,可实现改善电压质量和短路限流的双重功能,保证了电力系统安全性和稳定性。%For the voltage quality optimization under normal power operation, aiming at short-circuit fault in power system, a topology of dynamic voltage restorer with current limiting function (DVR-FCL) is proposed. A parameter design of DVR-FCL based on the objective function of current limiting impedance and the adjustment of DC voltage is introduced. The design methods of the DC link voltage, the output filter, series transformer capacity, the leakage reactance, the series converter and the DC link capacitor are analyzed in detail. The operations of DVR-FCL to voltage sag and short-circuit fault are respectively verified by PSCAD/EMTDC. Simulation results show that the proposed topology and parameters design methods are correct and reasonable, and can effectively realize the double functions of voltage quality improvement and fault current limiting. Thus, it can ensure the security and stability of power system.

  1. CLIP限流保护器在中压配电系统应用%Introduction on the application of CLIP current limiting device for MV distribution network

    Institute of Scientific and Technical Information of China (English)

    李锡芝

    2006-01-01

    @@ 1 工作原理和基本参数 1.1 工作原理 CLIP限流保护器(简称CLIP)属于转换型限流保护装置TCL(Triggered Current Limiter),是一种具有大持续载流能力的高速切换开关,俗称组合式限流熔断器.在欧洲、加拿大、美国和世界各地应用甚广.

  2. Eddy current imaging. Limits of the born approximation and advantages of an exact solution to the inverse problem; Imagerie par courants de Foucault. Limites de l`approximation de Born et interet d`une resolution exacte du probleme inverse

    Energy Technology Data Exchange (ETDEWEB)

    Hamman, E.; Zorgati, R.

    1995-12-31

    Eddy current non-destructive testing is used by EDF to detect flaws affecting conductive objects such as steam generator tubes. With a view to obtaining ever more accurate information on equipment integrity, thereby facilitating diagnosis, studies aimed at using measurements to reconstruct an image of the flaw have been proceeding now for about ten years. In this context, our approach to eddy current imaging is based on inverse problem formalism. The direct problem, involving a mathematical model linking measurements provided by a probe with variables characterizing the defect, is dealt with elsewhere. Using the model results, we study the possibility of inverting it, i.e. of reconstructing an image of the flaw from the measurements. We first give an overview of the different inversion techniques, representative of the state of the art and all based on linearization of the inverse problem by means of the Born approximation. The model error resulting from an excessive Born approximation nevertheless severely limits the quantity of the images which can be obtained. In order to counteract this often critical error and extend the eddy current imaging application field, we have to del with the non-linear inverse problem. A method derived from recent research is proposed and implemented to ensure consistency with the exact model. Based on an `optimization` type approach and provided with a convergence theorem, the method is highly efficient. (authors). 17 refs., 7 figs., 1 append.

  3. Two-phase flow experiments on Counter-Current Flow Limitation in a model of the hot leg of a pressurized water reactor (2015 test series)

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, Matthias; Lucas, Dirk; Pietruske, Heiko; Szalinski, Lutz

    2016-12-15

    Counter-Current Flow Limitation (CCFL) is of importance for PWR safety analyses in several accident scenarios connected with loss of coolant. Basing on the experiences obtained during a first series of hot leg tests now new experiments on counter-current flow limitation were conducted in the TOPFLOW pressure vessel. The test series comprises air-water tests at 1 and 2 bar as well as steam-water tests at 10, 25 and 50 bar. During the experiments the flow structure was observed along the hot leg model using a high-speed camera and web-cams. In addition pressure was measured at several positions along the horizontal part and the water levels in the reactor-simulator and steam-generator-simulator tanks were determined. This report documents the experimental setup including the description of operational and special measuring techniques, the experimental procedure and the data obtained. From these data flooding curves were obtained basing on the Wallis parameter. The results show a slight shift of the curves in dependency of the pressure. In addition a slight decrease of the slope was found with increasing pressure. Additional investigations concern the effects of hysteresis and the frequencies of liquid slugs. The latter ones show a dependency on pressure and the mass flow rate of the injected water. The data are available for CFD-model development and validation.

  4. AmpaCity. Superconducting cables and fault current limiters for the energy supply in conurbations; AmpaCity. Supraleitende Kabel und Strombegrenzer fuer die Energieverteilung in Ballungsgebieten

    Energy Technology Data Exchange (ETDEWEB)

    Merschel, F. [RWE Deutschland AG, Essen (Germany); Noe, M. [Karlsruher Institute of Technology (KIT), Karlsruhe (Germany); Stemmle, M. [Nexans Deutschland GmbH, Hannover (Germany); Hobl, A. [Nexans SuperConductors GmbH, Huerth (Germany); Sauerbach, O. [Westnetz GmbH, Essen (Germany)

    2013-07-01

    In 2013 RWE Germany is working jointly with cable manufacturer Nexans and with the scientific support of the Karlsruhe Institute of Technology (KIT) to install world's longest superconducting cable in the downtown area electricity grid of Essen. The AmpaCity project is partly funded by the German Federal Ministry of Economics and Technology and is playing an exemplary role in the further development of electricity grids in major cities worldwide. The project consortium presents AmpaCity as a convincing system solution especially with respect to economics and security of supply. Components of the system are a superconducting three-phase AC cable with two terminations and one connection joint in combination with a fault current limiter, which is also based on superconducting materials. The superconducting system is designed for 10 kV nominal voltage and 40 MW nominal power. It will replace a 110 kV cable system of equal capacity. At the same time, the project partners are paving the way for high failsafe performance, as the cable in conjunction with the fault current limiter cannot be overloaded by short circuit currents in the event of faults in the grid. Planning and follow up on the civil works in Essen posed a major challenge. Cable laying in the inner city, with various crossings of major highways, tramways, as well as already dense cable routes necessitated very thorough preparation and coordination. The civil works in Essen started in April 2013. At around the same time, after the cable had passed the type test, it went into production. Cable laying is scheduled for late summer. After commissioning, planned for the end of 2013, the field trial will run for at least two years under real grid conditions, to demonstrate this technology's suitability for wider deployment.

  5. Current Flow and Pair Creation at Low Altitude in Rotation-Powered Pulsars' Force-Free Magnetospheres: Space Charge Limited Flow

    Science.gov (United States)

    Timokhin, A. N.; Arons, J.

    2013-01-01

    We report the results of an investigation of particle acceleration and electron-positron plasma generation at low altitude in the polar magnetic flux tubes of rotation-powered pulsars, when the stellar surface is free to emit whatever charges and currents are demanded by the force-free magnetosphere. We apply a new 1D hybrid plasma simulation code to the dynamical problem, using Particle-in-Cell methods for the dynamics of the charged particles, including a determination of the collective electrostatic fluctuations in the plasma, combined with a Monte Carlo treatment of the high-energy gamma-rays that mediate the formation of the electron-positron pairs.We assume the electric current flowing through the pair creation zone is fixed by the much higher inductance magnetosphere, and adopt the results of force-free magnetosphere models to provide the currents which must be carried by the accelerator. The models are spatially one dimensional, and designed to explore the physics, although of practical relevance to young, high-voltage pulsars. We observe novel behaviour (a) When the current density j is less than the Goldreich-Julian value (0 1), the system develops high voltage drops (TV or greater), causing emission of curvature gamma-rays and intense bursts of pair creation. The bursts exhibit limit cycle behaviour, with characteristic time-scales somewhat longer than the relativistic fly-by time over distances comparable to the polar cap diameter (microseconds). (c) In return current regions, where j/j(sub GJ) rotating frame), finding that such steady flows can occupy only a small fraction of the current density parameter space exhibited by the force-free magnetospheric model. The generic polar flow dynamics and pair creation are strongly time dependent. The model has an essential difference from almost all previous quantitative studies, in that we sought the accelerating voltage (with pair creation, when the voltage drops are sufficiently large; without, when they are

  6. Current Health-Related Quality of Life in Former National Collegiate Athletic Association Division I Collision Athletes Compared With Contact and Limited-Contact Athletes.

    Science.gov (United States)

    Simon, Janet E; Docherty, Carrie L

    2016-03-01

    Previous researchers have shown that current health-related quality of life (HRQoL) is lower in former National Collegiate Athletic Association Division I athletes than in nonathletes. However, evidence supports the idea that individuals in collision sports (football) may suffer more serious injuries that may affect them later in life. To measure HRQoL in former Division I collision, contact, and limited-contact athletes. Cross-sectional study. Research laboratory. A total of 374 former Division I athletes between the ages of 40 and 65 years were separated into collision, contact, and limited-contact groups. All individuals completed the Short Form 36 version 2 via a computer. The dependent variables were the physical component and mental component summary scores and the physical functioning, physical role functioning, bodily pain, general health, vitality, social role functioning, emotional role functioning, and mental health scales. An initial multivariate analysis of covariance included data from the 2 domains: physical component and mental component summary scores. The second multivariate analysis of covariance included data from the 8 dimensions: physical function, role physical, bodily pain scale, general health, mental health, role emotional, social function, and vitality scales. The α level was set at P contact and limited-contact athletes for the summary scores (F2,370 = 90.09, P contact athletes for the bodily pain and role physical scales, with mean differences of 12.91 and 11.80 points, respectively. Competing at the Division I level can be strenuous on an athlete's physical, mental, and social dimensions, which can affect the athlete later in life. Based on these data, collision athletes may sacrifice their future HRQoL compared with contact and limited-contact athletes.

  7. Experimental Characterisation of the Interfacial Structure during Counter-Current Flow Limitation in a Model of the Hot Leg of a PWR

    Directory of Open Access Journals (Sweden)

    Christophe Vallée

    2012-01-01

    Full Text Available In order to investigate the two-phase flow behaviour during counter-current flow limitation in the hot leg of a pressurised water reactor, dedicated experiments were performed in a scaled down model of Kobe University. The experiments were performed with air and water at atmospheric pressure and room temperature. At high flow rates, CCFL occurs and the discharge of water to the reactor pressure vessel simulator is limited by the formation of slugs carrying liquid back to the steam generator. The structure of the interface was observed from the side of the channel test section using a high-speed video camera. An algorithm was developed to recognise the stratified interface in the camera frames after background subtraction. This method allows extracting the water level at any position in the image as well as performing further statistical treatments. The evolution of the interfacial structure along the horizontal part of the hot leg is shown by the visualisation of the probability distribution of the water level and analysed in function of the liquid and gas flow rates. The data achieved are useful for the analysis of the flow conditions as well as for the validation of modelling approaches like computational fluid dynamics.

  8. Intrinsic limits on resolutions in muon- and electron-neutrino charged-current events in the KM3NeT/ORCA detector

    Science.gov (United States)

    Adrián-Martínez, S.; Ageron, M.; Aiello, S.; Albert, A.; Ameli, F.; Anassontzis, E. G.; Andre, M.; Androulakis, G.; Anghinolfi, M.; Anton, G.; Ardid, M.; Avgitas, T.; Barbarino, G.; Barbarito, E.; Baret, B.; Barrios-Mart, J.; Belias, A.; Berbee, E.; van den Berg, A.; Bertin, V.; Beurthey, S.; van Beveren, V.; Beverini, N.; Biagi, S.; Biagioni, A.; Billault, M.; Bondì, M.; Bormuth, R.; Bouhadef, B.; Bourlis, G.; Bourret, S.; Boutonnet, C.; Bouwhuis, M.; Bozza, C.; Bruijn, R.; Brunner, J.; Buis, E.; Buompane, R.; Busto, J.; Cacopardo, G.; Caillat, L.; Calamai, M.; Calvo, D.; Capone, A.; Caramete, L.; Cecchini, S.; Celli, S.; Champion, C.; Cherubini, S.; Chiarella, V.; Chiarelli, L.; Chiarusi, T.; Circella, M.; Classen, L.; Cobas, D.; Cocimano, R.; Coelho, J. A. B.; Coleiro, A.; Colonges, S.; Coniglione, R.; Cordelli, M.; Cosquer, A.; Coyle, P.; Creusot, A.; Cuttone, G.; D'Amato, C.; D'Amico, A.; D'Onofrio, A.; De Bonis, G.; De Sio, C.; Di Palma, I.; Díaz, A. F.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti-Hasankiadeh, Q.; Drakopoulou, E.; Drouhin, D.; Durocher, M.; Eberl, T.; Eichie, S.; van Eijk, D.; El Bojaddaini, I.; Elsaesser, D.; Enzenhöfer, A.; Favaro, M.; Fermani, P.; Ferrara, G.; Frascadore, G.; Furini, M.; Fusco, L. A.; Gal, T.; Galatà, S.; Garufi, F.; Gay, P.; Gebyehu, M.; Giacomini, F.; Gialanella, L.; Giordano, V.; Gizani, N.; Gracia, R.; Graf, K.; Grégoire, T.; Grella, G.; Grmek, A.; Guerzoni, M.; Habel, R.; Hallmann, S.; van Haren, H.; Harissopulos, S.; Heid, T.; Heijboer, A.; Heine, E.; Henry, S.; Hernández-Rey, J. J.; Hevinga, M.; Hofestädt, J.; Hugon, C. M. F.; Illuminati, G.; James, C. W.; Jansweijerf, P.; Jongen, M.; de Jong, M.; Kadler, M.; Kalekin, O.; Kappes, A.; Katz, U. F.; Keller, P.; Kieft, G.; Kießling, D.; Koffeman, E. N.; Kooijman, P.; Kouchner, A.; Kreter, M.; Kulikovskiy, V.; Lahmann, R.; Lamare, P.; Larosa, G.; Leisos, A.; Leone, F.; Leonora, E.; Lindsey Clark, M.; Liolios, A.; Llorens Alvarez, C. D.; Lo Presti, D.; Löhner, H.; Lonardo, A.; Lotze, M.; Loucatos, S.; Maccioni, E.; Mannheim, K.; Manzali, M.; Margiotta, A.; Margotti, A.; Marinelli, A.; Maris, O.; Markou, C.; Martínez-Mora, J. A.; Martini, A.; Marzaioli, F.; Mele, R.; Melis, K. W.; Michael, T.; Migliozzi, P.; Migneco, E.; Mijakowski, P.; Miraglia, A.; Mollo, C. M.; Mongelli, M.; Morganti, M.; Moussa, A.; Musico, P.; Musumeci, M.; Navas, S.; Nicolau, C. A.; Olcina, I.; Olivetto, C.; Orlando, A.; Orzelli, A.; Pancaldi, G.; Papaikonomou, A.; Papaleo, R.; Păvălas, G. E.; Peek, H.; Pellegrini, G.; Pellegrino, C.; Perrina, C.; Pfutzner, M.; Piattelli, P.; Pikounis, K.; Pleinert, M.-O.; Poma, G. E.; Popa, V.; Pradier, T.; Pratolongo, F.; Pühlhofer, G.; Pulvirenti, S.; Quinn, L.; Racca, C.; Raffaelli, F.; Randazzo, N.; Rauch, T.; Real, D.; Resvanis, L.; Reubelt, J.; Riccobene, G.; Rossi, C.; Rovelli, A.; Saldaña, M.; Salvadori, I.; Samtleben, D. F. E.; Sánchez García, A.; Sánchez Losa, A.; Sanguineti, M.; Santangelo, A.; Santonocito, D.; Sapienza, P.; Schimmel, F.; Schmelling, J.; Schnabel, J.; Sciacca, V.; Sedita, M.; Seitz, T.; Sgura, I.; Simeone, F.; Sipala, V.; Spisso, B.; Spurio, M.; Stavropoulos, G.; Steijger, J.; Stellacci, S. M.; Stransky, D.; Taiuti, M.; Tayalati, Y.; Terrasi, F.; Tézier, D.; Theraube, S.; Timmer, P.; Tönnis, C.; Trasatti, L.; Travaglini, R.; Trovato, A.; Tsirigotis, A.; Tzamarias, S.; Tzamariudaki, E.; Vallage, B.; Van Elewyck, V.; Vermeulen, J.; Versari, F.; Vicini, P.; Viola, S.; Vivolo, D.; Volkert, M.; Wiggers, L.; Wilms, J.; de Wolf, E.; Zachariadou, K.; Zani, S.; Zornoza, J. D.; Zúñiga, J.

    2017-05-01

    Studying atmospheric neutrino oscillations in the few-GeV range with a multi-megaton detector promises to determine the neutrino mass hierarchy. This is the main science goal pursued by the future KM3NeT/ORCA water Cherenkov detector in the Mediterranean Sea. In this paper, the processes that limit the obtainable resolution in both energy and direction in charged-current neutrino events in the ORCA detector are investigated. These processes include the composition of the hadronic fragmentation products, the subsequent particle propagation and the photon-sampling fraction of the detector. GEANT simulations of neutrino interactions in seawater produced by GENIE are used to study the effects in the 1-20 GeV range. It is found that fluctuations in the hadronic cascade in conjunction with the variation of the inelasticity y are most detrimental to the resolutions. The effect of limited photon sampling in the detector is of significantly less importance. These results will therefore also be applicable to similar detectors/media, such as those in ice. [Figure not available: see fulltext.

  9. Leakage current limiting mechanisms and ferroelectric properties of BiAlO3/La0.67Sr0.33MnO3 heterostructure

    Science.gov (United States)

    Zhao, Yanan; Luo, Bingcheng; Chen, Changle; Xing, Hui; Wang, Jianyuan; Jin, Kexin

    2017-03-01

    The BiAlO3/La0.67Sr0.33MnO3 heterostructure was deposited on LaAlO3 (111) substrate by pulse laser deposition technology. X-ray diffraction measurement indicates that BiAlO3 thin films belong to tetragonal phase. Two different leakage current mechanisms, i.e., Space Charge Limited Current and Schottky emission models are observed in J-E characteristics of BiAlO3/La0.67Sr0.33MnO3 heterostructure in different temperature regions, respectively. The ferroelectric hysteresis loops measured by positive-up negative-down method show intrinsic remnant polarization (2Pr = 2.4 μC/cm2) at the applied electric field of 750 kV/cm, with the 80 nm thickness of BiAlO3 thin films at room temperature. The domain imagines and local piezoelectric hysteresis loops obtained by Piezoresponse Force Microscopy technique further reveal the intrinsic ferroelectricity of. BiAlO3 thin films at room temperature.

  10. CFD studies on the phenomena around counter-current flow limitations of gas/liquid two-phase flow in a model of a PWR hot leg

    Energy Technology Data Exchange (ETDEWEB)

    Deendarlianto, E-mail: deendarlianto@ugm.ac.id [Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Department of Mechanical and Industrial Engineering, Faculty of Engineering, Gadjah Mada University, Jalan Grafika No. 2, Yogyakarta 55281 (Indonesia); Hoehne, Thomas; Lucas, Dirk; Vallee, Christophe [Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Zabala, Gustavo Adolfo Montoya [Department of Chemical Engineering, Simon Bolivar University, Valle of Sartenejas, Caracas 1080 (Venezuela, Bolivarian Republic of)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer We modelled CCFL in a PWR hot leg using Algebraic Interfacial Area Density model. Black-Right-Pointing-Pointer The model is able to distinguish the local flow morphologies. Black-Right-Pointing-Pointer Test fluids are air-water and steam-water. Black-Right-Pointing-Pointer Calculated CCFL and water level are in good agreement with experimental data. - Abstract: In order to improve the understanding of counter-current two-phase flow and to validate new physical models, CFD simulations of a 1/3rd scale model of the hot leg of a German Konvoi pressurized water reactor (PWR) with rectangular cross section were performed. Selected counter-current flow limitation (CCFL) experiments conducted at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) were calculated with ANSYS CFX using the multi-fluid Euler-Euler modelling approach. The transient calculations were carried out using a gas/liquid inhomogeneous multiphase flow model coupled with a shear stress transport (SST) turbulence model. In the simulation, the drag law was approached by a newly developed correlation of the drag coefficient in the Algebraic Interfacial Area Density (AIAD) model. The model can distinguish the bubbles, droplets and the free surface using the local liquid phase volume fraction value. A comparison with the high-speed video observations shows a good qualitative agreement. The results indicate also a quantitative agreement between calculations and experimental data for the CCFL characteristics and the water level inside the hot leg channel.

  11. Current components, physical, and other data from moored current meters and CTD casts from NOAA Ship DISCOVERER and other platforms from the NE Pacific (limit-180) as part of the VENTS program from 1985-06-03 to 1991-06-11 (NCEI Accession 9200073)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current components, physical, and other data from moored current meters and CTD casts from NOAA Ship DISCOVERER and other platforms from the NE Pacific (limit-180)....

  12. Current, profile, and other data from current meters and CTD casts from NOAA Ship DISCOVERER and other platforms from the NW Pacific (limit-180) as part of the VENTS program from 1991-06-11 to 1992-06-11 (NCEI Accession 9300078)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current, profile, and other data were collected from current meters and CTD casts from NOAA Ship Discoverer and other platforms from the NW Pacific (limit-180) from...

  13. Food composition tables in resource-poor settings: exploring current limitations and opportunities, with a focus on animal-source foods in sub-Saharan Africa.

    Science.gov (United States)

    de Bruyn, Julia; Ferguson, Elaine; Allman-Farinelli, Margaret; Darnton-Hill, Ian; Maulaga, Wende; Msuya, John; Alders, Robyn

    2016-11-08

    Animal-source foods (ASF) have the potential to enhance the nutritional adequacy of cereal-based diets in low- and middle-income countries, through the provision of high-quality protein and bioavailable micronutrients. The development of guidelines for including ASF in local diets requires an understanding of the nutrient content of available resources. This article reviews food composition tables (FCT) used in sub-Saharan Africa, examining the spectrum of ASF reported and exploring data sources for each reference. Compositional data are shown to be derived from a small number of existing data sets from analyses conducted largely in high-income nations, often many decades previously. There are limitations in using such values, which represent the products of intensively raised animals of commercial breeds, as a reference in resource-poor settings where indigenous breed livestock are commonly reared in low-input production systems, on mineral-deficient soils and not receiving nutritionally balanced feed. The FCT examined also revealed a lack of data on the full spectrum of ASF, including offal and wild foods, which correspond to local food preferences and represent valuable dietary resources in food-deficient settings. Using poultry products as an example, comparisons are made between compositional data from three high-income nations, and potential implications of differences in the published values for micronutrients of public health significance, including Fe, folate and vitamin A, are discussed. It is important that those working on nutritional interventions and on developing dietary recommendations for resource-poor settings understand the limitations of current food composition data and that opportunities to improve existing resources are more actively explored and supported.

  14. Study of counter current flow limitation model of MARS-KS and SPACE codes under Dukler's air/water flooding test conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Woong; Kim, Min Gil; Lee, Jeong Ik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Bang, Young Seok [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-10-15

    In particular, CCFL(the counter current flow limitation) occurs in components such as hot leg, downcomer annulus and steam generator inlet plenum during LOCA which is possible to have flows in two opposite directions. Therefore, CCFL is one of the thermal-hydraulic models which has significant effect on the reactor safety analysis code performance. In this study, the CCFL model will be evaluated with MARS-KS based on two-phase two-field governing equations and SPACE code based on two-phase three-field governing equations. This study will be conducted by comparing MARS-KS code which is being used for evaluating the safety of a Korean Nuclear Power Plant and SPACE code which is currently under assessment for evaluating the safety of the designed nuclear power plant. In this study, comparison of the results of liquid upflow and liquid downflow rate for different gas flow rate from two code to the famous Dukler's CCFL experimental data are presented. This study will be helpful to understand the difference between system analysis codes with different governing equations, models and correlations, and further improving the accuracy of system analysis codes. In the nuclear reactor system, CCFL is an important phenomenon for evaluating the safety of nuclear reactors. This is because CCFL phenomenon can limit injection of ECCS water when CCFL occurs in components such as hot leg, downcomer annulus or steam generator inlet plenum during LOCA which is possible to flow in two opposite directions. Therefore, CCFL is one of the thermal-hydraulic models which has significant effect on the reactor safety analysis code performance. In this study, the CCFL model was evaluated with MARS-KS and SPACE codes for studying the difference between system analysis codes with different governing equations, models and correlations. This study was conducted by comparing MARS-KS and SPACE code results of liquid upflow and liquid downflow rate for different gas flow rate to the famous Dukler

  15. A Scheme for Current-limiting Hybrid DC Circuit Breaker%一种限流式混合直流断路器方案

    Institute of Scientific and Technical Information of China (English)

    江道灼; 张弛; 郑欢; 叶李心; 严玉婷

    2014-01-01

    for high-voltage DC-breakers. Furthermore,a scheme of hybrid DC-breakers with fault current limiting is proposed, its feasibility verified through simulation.In this scheme the DC-breaker adopts the hybrid solid-state switch (composed of half and full gate-controlled devices in series connection) which is paralleled with a mechanical breaker involving the fault-current-limiting technology. Therefore the rising rate of short-circuit current can be effectively restrained,relieving the requirement on fault diagnosis sensitivity and mechanical breaker speed.Moreover,the series quantities of solid-state switching devices (especially the expensive full gate-controlled devices such as the insulated gate bipolar transistor)in high voltage application,and the technical difficulty and production costs etc will be reduced.

  16. Current meter components and other data from FIXED PLATFORMS from NW Pacific (limit-180) in support of the Emperor Seamount Experiment from 28 June 1982 to 01 November 1983 (NODC Accession 8500287)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter components data were collected from FIXED PLATFORMS in the NW Pacific (limit-180) from 28 June 1982 to 01 November 1983 . Data were collected by the...

  17. Analysis of Limiting Measures of Three-phase Short-circuit Current of 500kV Intensive Receiving-end Power Grid in the Early Stage of UHV Construction

    Directory of Open Access Journals (Sweden)

    Zhang Xiao Hang

    2016-01-01

    Full Text Available This paper took the intensive receiving-end power grid as the research object and analysed the problems of three-phase short-circuit current over-limited of 500kV intensive power grid in the early stage of UHV construction. Firstly, this paper analysed the influence factors of the short-circuit current based on self-impedance analysis model of two-port network theory and the equivalent model of UHV power grid. Then, the applicable current-limiting measures were put forward. Finally, this paper proposed one scheme to solve the problems of three-phase short-circuit current over-limited of 500kV buses in one practical receiving-end power grid and verified the feasibility of this scheme from three different aspects. Aiming at the over-limited influential factors, the applicable current-limiting measures can be taken as follows: separating the 500kV bus at UHV substation, lapping the lines outside the substation and decentralizing the power supplies. The proposed measures can effectively solve the problems of short-circuit current over-limited in the early stage of UHV construction and provide reference for other power grid.

  18. Current limitations of SNP data from the public domain for studies of complex disorders: a test for ten candidate genes for obesity and osteoporosis

    Directory of Open Access Journals (Sweden)

    Xiao Peng

    2004-02-01

    Full Text Available Abstract Background Public SNP databases are frequently used to choose SNPs for candidate genes in the association and linkage studies of complex disorders. However, their utility for such studies of diseases with ethnic-dependent background has never been evaluated. Results To estimate the accuracy and completeness of SNP public databases, we analyzed the allele frequencies of 41 SNPs in 10 candidate genes for obesity and/or osteoporosis in a large American-Caucasian sample (1,873 individuals from 405 nuclear families by PCR-invader assay. We compared our results with those from the databases and other published studies. Of the 41 SNPs, 8 were monomorphic in our sample. Twelve were reported for the first time for Caucasians and the other 29 SNPs in our sample essentially confirmed the respective allele frequencies for Caucasians in the databases and previous studies. The comparison of our data with other ethnic groups showed significant differentiation between the three major world ethnic groups at some SNPs (Caucasians and Africans differed at 3 of the 18 shared SNPs, and Caucasians and Asians differed at 13 of the 22 shared SNPs. This genetic differentiation may have an important implication for studying the well-known ethnic differences in the prevalence of obesity and osteoporosis, and complex disorders in general. Conclusion A comparative analysis of the SNP data of the candidate genes obtained in the present study, as well as those retrieved from the public domain, suggests that the databases may currently have serious limitations for studying complex disorders with an ethnic-dependent background due to the incomplete and uneven representation of the candidate SNPs in the databases for the major ethnic groups. This conclusion attests to the imperative necessity of large-scale and accurate characterization of these SNPs in different ethnic groups.

  19. From an 'ice-see' perspective: The current use, potential and limitations of Structure-from-Motion photogrammetry for cryospheric applications

    Science.gov (United States)

    Westoby, Matthew; Dunning, Stuart; Allan, Mark; Smith, Mark; Quincey, Duncan; Carrivick, Jonathan; Watson, C. Scott

    2016-04-01

    Structure-from-Motion with Multi-View Stereo (SfM-MVS) methods are rapidly becoming the tool of choice for geoscientists who require a relatively low-cost and viable alternative to traditional surveying technologies for characterising the form and short-term evolution of Earth surface landforms and landscapes. Uptake of SfM-MVS methods by workers in the cryospheric science community has been particularly rapid. The choice to use SfM-MVS has many logistical benefits which promote its adoption in remote glacial environments, namely the requirement for little more than a digital camera and proprietary or open-source software for topographic reconstruction, and a surveyed network of ground control to transform the resultant 3D models into a real-world co-ordinate system, if desired. Optionally, a dedicated aerial photography platform (e.g. kite, blimp, multirotor or fixed-wing UAV) may be used for initial photograph acquisition, which can facilitate glacier-scale observation and analysis. To date, cryospheric applications of SfM-MVS have included: the monitoring of glacier, moraine, and rock glacier movement; the evolution of ice cliffs on debris-covered glaciers; the reconstruction of ice-marginal or deglaciated topography; patch- and moraine-scale sedimentological characterisation; and the characterisation of glacier surfaces to monitor supraglacial drainage development or to inform energy balance modelling. This contribution will showcase existing applications and original data and discuss exciting potential opportunities and current limitations of the SfM-MVS method for the cryospheric sciences.

  20. Current meter and other data collected using current meter in the NW Atlantic (limit-40 W) from ENDEAVOR and other platforms from 16 September 1980 to 12 May 1983 (NODC Accession 8600198)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter and other data were collected using current meter (PCM) casts from G. B. KELEZ, ENDEAVOR, and CAPE HATTERAS in the Northwest Atlantic Ocean. Data were...

  1. Limits to the critical current in Bi2Sr2Ca2Cu3Ox tape conductors: The parallel path model

    NARCIS (Netherlands)

    van der Laan, D.C.; Schwartz, J.; ten Haken, Bernard; Dhalle, M.; van Eck, H.J.N.

    2008-01-01

    An extensive overview of a model that describes current flow and dissipation in high-quality Bi2Sr2Ca2Cu3Ox superconducting tapes is provided. The parallel path model is based on a superconducting current running in two distinct parallel paths. One of the current paths is formed by grains that are

  2. A limited contribution of Ca2+ current facilitation to paired-pulse facilitation of transmitter release at the rat calyx of Held

    OpenAIRE

    Mueller, Martin; Felmy, Felix; Schneggenburger, Ralf

    2008-01-01

    Recent studies have suggested that transmitter release facilitation at synapses is largely mediated by presynaptic Ca2+ current facilitation, but the exact contribution of Ca2+ current facilitation has not been determined quantitatively. Here, we determine the contribution of Ca2+ current facilitation, and of an increase in the residual free Ca2+ concentration ([Ca2+](i)) in the nerve terminal, to paired-pulse facilitation of transmitter release at the calyx of Held. Under conditions of low r...

  3. A limited contribution of Ca2+ current facilitation to paired-pulse facilitation of transmitter release at the rat calyx of Held.

    Science.gov (United States)

    Müller, Martin; Felmy, Felix; Schneggenburger, Ralf

    2008-11-15

    Recent studies have suggested that transmitter release facilitation at synapses is largely mediated by presynaptic Ca(2+) current facilitation, but the exact contribution of Ca(2+) current facilitation has not been determined quantitatively. Here, we determine the contribution of Ca(2+) current facilitation, and of an increase in the residual free Ca(2+) concentration ([Ca(2+)](i)) in the nerve terminal, to paired-pulse facilitation of transmitter release at the calyx of Held. Under conditions of low release probability imposed by brief presynaptic voltage-clamp steps, transmitter release facilitation at short interstimulus intervals (4 ms) was 227 +/- 31% of control, Ca(2+) current facilitation was 113 +/- 4% of control, and the peak residual [Ca(2+)](i) was 252 +/- 18 nm over baseline. By inferring the 'local' [Ca(2+)](i) transients that drive transmitter release during these voltage-clamp stimuli with the help of a kinetic release model, we estimate that Ca(2+) current facilitation contributes to approximately 40% to paired-pulse facilitation of transmitter release. The remaining component of facilitation strongly depends on the build-up, and on the decay of the residual free [Ca(2+)](i), but cannot be explained by linear summation of the residual free [Ca(2+)](i), and the back-calculated 'local' [Ca(2+)](i) signal, which only accounts for approximately 10% of the total release facilitation. Further voltage-clamp experiments designed to compensate for Ca(2+) current facilitation demonstrated that about half of the observed transmitter release facilitation remains in the absence of Ca(2+) current facilitation. Our results indicate that paired-pulse facilitation of transmitter release at the calyx of Held is driven by at least two distinct mechanisms: Ca(2+) current facilitation, and a mechanism independent of Ca(2+) current facilitation that closely tracks the time course of residual free [Ca(2+)](i).

  4. Current limits and future challenges in the management of renal dysfunction in patients with cirrhosis: report from the International Club of Ascites

    DEFF Research Database (Denmark)

    Angeli, Paolo; Sanyal, Arun; Møller, Søren

    2013-01-01

    is based either on the more recent knowledge on renal dysfunction in advanced cirrhosis or current opinions among the members of the International Club of Ascites (ICA) on the management of this complication, obtained through a survey and discussed during the EASL-ICA Joint Meeting in Berlin in March 2011....... It reviews critically our current knowledge and it outlines future perspectives, on the management of renal dysfunction in patients with cirrhosis....

  5. Study on Fault Current Limiter and Power Transmission Pilot Protection Matching Issue%故障限流器与输电线路纵联保护相配合问题的研究

    Institute of Scientific and Technical Information of China (English)

    董权力; 王佳成; 时斌; 李浩

    2014-01-01

    Introduction was made to the pilot protection principle of directional locking type. By Matlab software simulation model, this paper described the impact on circuits at time of different current limiting induction of bridge current limiter, analyzing impact of fault cur-rent limiter on current limiting induction and distance pilot protection. The result shows that with the fault current limiter added, the per-formance of current transformer could be improved, so as to prevent it from saturation, to reduce unbalanced current, but to cause power direction relay unwanted operation with sequence component as judging basis, which affects pilot protection correct work of applied power direction element.%介绍了方向闭锁式纵联保护原理,通过Matlab软件搭建仿真模型,描述了桥式限流器的限流电感不同时对电路产生的影响,分析了故障限流器对限流电感及距离纵联保护的影响,结果表明,加入故障限流器能改善电流互感器的性能,防止其饱和,减小不平衡电流,也可能造成以序分量为判断依据的功率方向继电器误动,妨碍应用了功率方向元件的纵联保护正确工作。

  6. Elaboration and characterization of superconducting Bi:2223 ceramics with a view to fault current limiters; Elaboration et caracterisation de ceramiques supraconductrices Bi:2223 en vue de la limitation du courant

    Energy Technology Data Exchange (ETDEWEB)

    Noudem, J.G.; Porcar, L. [CNRS, Grenoble (France). EPM-Matformag]|[Schneider Electric S.A., Grenoble (France); Belmont, O.; Bourgault, D.; Tixador, P.; Beille, J.; Tournier, R. [CNRS, Grenoble (France). EPM-Matformag; Sanchez, J.; Barbut, J.M.; Barrault, M. [Schneider Electric S.A., Grenoble (France)

    1998-01-01

    High pulsed currents with a duration varying from 1.25 to 20 ms have been applied at 77 K to sintered and textured samples. For I > I{sub c}, two types of behaviour are observed: when the average temperature of the sample is lower than T{sub c}, a critical current is recovered at the end of the pulse. Above T{sub c}, samples remain normal after the pulse because the sample temperature is too high leading to a maximum instantaneous applied power up to 182 GW/m{sup 3} in the sintered sample. At 15I{sub c} electric fields of 400 V/m and 1000 V/m are observed for the sintered and textured samples respectively. (orig.). 5 refs.

  7. Intrinsic limits on resolutions in muon- and electron-neutrino charged-current events in the KM3NeT/ORCA detector

    NARCIS (Netherlands)

    The KM3NeT collaboration; Adrián-Martínez, S.; Ageron, M.; Aiello, S.; Albert, A.; Ameli, F.; Anassontzis, E.G.; Andre, M.; Androulakis, G.; Anghinolfi, M.; Anton, G.; Ardid, M.; Avgitas, T.; Barbarino, G.; Barbarito, E.; Baret, B.; Barrios-Mart, J.; Belias, A.; Berbee, E.; Berg, A. van den; Bertin, V.; Beurthey, S.; Beveren, V. van; Beverini, N.; Biagi, S.; Biagioni, A.; Billault, M.; Bondì, M.; Bormuth, R.; Bouhadef, B.; Bourlis, G.; Bourret, S.; Boutonnet, C.; Bouwhuis, M.; Bozza, C.; Bruijn, R.; Brunner, J.; Buis, E.; Buompane, R.; Busto, J.; Cacopardo, G.; Caillat, L.; Calamai, M.; Calvo, D.; Capone, A.; Caramete, L.; Cecchini, S.; Celli, S.; Champion, C.; Cherubini, S.; Chiarella, V.; Chiarelli, L.; Chiarusi, T.; Circella, M.; Classen, L.; Cobas, D.; Cocimano, R.; Coelho, J.A.B.; Coleiro, A.; Colonges, S.; Coniglione, R.; Cordelli, M.; Cosquer, A.; Coyle, P.; Creusot, A.; Cuttone, G.; D’Amato, C.; D’Amico, A.; D’Onofrio, A.; De Bonis, G.; De Sio, C.; Di Palma, I.; Díaz, A.F.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti-Hasankiadeh, Q.; Drakopoulou, E.; Drouhin, D.; Durocher, M.; Eberl, T.; Eichie, S.; Eijk, D. van; El Bojaddaini, I.; Elsaesser, D.; Enzenhöfer, A.; Favaro, M.; Fermani, P.; Ferrara, G.; Frascadore, G.; Furini, M.; Fusco, L.A.; Gal, T.; Galatà, S.; Garufi, F.; Gay, P.; Gebyehu, M.; Giacomini, F.; Gialanella, L.; Giordano, V.; Gizani, N.; Gracia, R.; Graf, K.; Grégoire, T.; Grella, G.; Grmek, A.; Guerzoni, M.; Habel, R.; Hallmann, S.; Haren, H. van; Harissopulos, S.; Heid, T.; Heijboer, A.; Heine, E.; Henry, S.; Hernández-Rey, J.J.; Hevinga, M.; Hofestädt, J.; Hugon, C.M.F.; Illuminati, G.; James, C.W.; Jansweijerf, P.; Jongen, M.; Jong, M. de; Kadler, M.; Kalekin, O.; Kappes, A.; Katz, U.F.; Keller, P.; Kieft, G.; Kießling, D.; Koffeman, E.N.; Kooijman, P.; Kouchner, A.; Kreter, M.; Kulikovskiy, V.; Lahmann, R.; Lamare, P.; Larosa, G.; Leisos, A.; Leone, F.; Leonora, E.; Lindsey Clark, M.; Liolios, A.; Llorens Alvarez, C.D.; Lo Presti, D.; Löhner, H.; Lonardo, A.; Lotze, M.; Loucatos, S.; Maccioni, E.; Mannheim, K.; Manzali, M.; Margiotta, A.; Margotti, A.; Marinelli, A.; Maris, O.; Markou, C.; Martínez-Mora, J.A.; Martini, A.; Marzaioli, F.; Mele, R.; Melis, K.W.; Michael, T.; Migliozzi, P.; Migneco, E.; Mijakowski, P.; Miraglia, A.; Mollo, C.M.; Mongelli, M.; Morganti, M.; Moussa, A.; Musico, P.; Musumeci, M.; Navas, S.; Nicolau, C.A.; Olcina, I.; Olivetto, C.; Orlando, A.; Orzelli, A.; Pancaldi, G.; Papaikonomou, A.; Papaleo, R.; Păvălas, G.E.; Peek, H.; Pellegrini, G.; Pellegrino, C.; Perrina, C.; Pfutzner, M.; Piattelli, P.; Pikounis, K.; Pleinert, M.O.; Poma, G.E.; Popa, V.; Pradier, T.; Pratolongo, F.; Pühlhofer, G.; Pulvirenti, S.; Quinn, L.; Racca, C.; Raffaelli, F.; Randazzo, N.; Rauch, T.; Real, D.; Resvanis, L.; Reubelt, J.; Riccobene, G.; Rossi, C.; Rovelli, A.; Saldaña, M.; Salvadori, I.; Samtleben, D.F.E.; Sánchez García, A.; Sánchez Losa, A.; Sanguineti, M.; Santangelo, A.; Santonocito, D.; Sapienza, P.; Schimmel, F.; Schmelling, J.; Schnabel, J.; Sciacca, V.; Sedita, M.; Seitz, T.; Sgura, I.; Simeone, F.; Sipala, V.; Spisso, B.; Spurio, M.; Stavropoulos, G.; Steijger, J.; Stellacci, S.M.; Stransky, D.; Taiuti, M.; Tayalati, Y.; Terrasi, F.; Tézier, D.; Theraube, S.; Timmer, P.; Tönnis, C.; Trasatti, L.; Travaglini, R.; Trovato, A.; Tsirigotis, A.; Tzamarias, S.; Tzamariudaki, E.; Vallage, B.; Elewyck, V. van; Vermeulen, J.; Versari, F.; Vicini, P.; Viola, S.; Vivolo, D.; Volkert, M.; Wiggers, L.; Wilms, J.; Wolf, E. de; Zachariadou, K.; Zani, S.; Zornoza, J.D.; Zúñiga, J.

    2017-01-01

    Studying atmospheric neutrino oscillations in the few-GeV range with a multi-megaton detector promises to determine the neutrino mass hierarchy. This is the main science goal pursued by the future KM3NeT/ORCA water Cherenkov detector in the Mediterranean Sea. In this paper, the processes that limit

  8. EMIC-wave-moderated flux limitations of ring current energetic ion intensities in the multi-species plasmas of Earth's inner magnetosphere

    Science.gov (United States)

    Mauk, B.

    2013-12-01

    One of the early sophisticated integrations of theory and observations of the space age was the development in 1966 of the integral Kennel-Petschek flux limit for trapped energetic electrons and ions within Earth's inner magnetosphere. Specifically, it was proposed that: 1) trapped particle distributions in the magnetic bottle configuration of the inner magnetosphere are intrinsically unstable to the generation various plasma waves and 2) ionospheric reflection of some waves back into the trapped populations leads to runaway growth of the waves and dramatic loss of particles for particle integral intensities that rise above a fairly rigidly specified upper limit. While there has been a long hiatus in utilization of the KP limit in inner magnetospheric research, there have been recent highly successful reconsiderations of more general forms of the KP limit for understanding radiation belt electron intensities and spectral shapes, resulting from improvements in theoretical tools. Such a reconsideration has not happened for energetic trapped ions, perhaps due to the perceived immense complexity of the generation of the Electromagnetic Ion Cyclotron (EMIC) waves, that scatter the energetic ions, for plasmas containing multiple ionic species (H, He, O). Here, a differential Kennel-Petschek (KP) flux limit for magnetospheric energetic ions is devised taking into account multiple ion species effects on the EMIC waves. This new theoretical approach is applied to measured Earth magnetosphere energetic ion spectra (~ keV to ~ 1 MeV) for radial positions (L) 3 to 6.7 RE. The flatness of the most intense spectral shapes for mechanism, but modifications of traditional KP parameters are needed to account for maximum intensities up to 5 times greater than expected. Future work using the Van Allen Probes mission will likely resolve outstanding uncertainties.

  9. Introduction of a current waveform, waveshaping technique to limit conduction loss in high-frequency dc-dc converters suitable for space power

    Science.gov (United States)

    Miller, Douglas P.

    1990-06-01

    Space power supply manufacturers have tried to increase power density and construct smaller, highly efficient power supplies by increasing switching frequency. Incorporation of a power MOSFET as a switching element alleviates switching loss. However, values of R sub DS(on) (drain-to-source resistance in the on-state) for MOSFET's are of such magnitude to produce greater on-state losses than an equivalent BJT operated in saturation. This research serves to introduce a design concept, pertinent to low-voltage relatively-high-current applications, that minimizes the peak current through the switching element in order to reduce average power loss. Basic waveforms produced by different PWM and resonant mode topologies were examined. Theoretical analysis reveals that a ramp-sine current waveform could cut conduction power loss by at least 18 percent over a conventional Buck switching converter. A 14V, 14W combination quasi-resonant Buck/ZCS, Quasi-Resonant Buck dc-dc converter with an unregulated input voltage of 28 V was built for simplicity to demonstrate one particular waveshaping technique. This converter represents a useful example of an actual circuit which is capable of producing the desired ramp-sine switch-current waveform. Final results confirm improvement in conduction loss enhancing existing power MOSFET technology for use in dc-dc power conversion.

  10. An ecotoxicological analysis of the sediment quality in a European Atlantic harbor emphasizes the current limitations of the Water Framework Directive.

    Science.gov (United States)

    Gonçalves, Sandra F; Calado, Ricardo; Gomes, Newton C M; Soares, Amadeu M V M; Loureiro, Susana

    2013-07-15

    The "PortoNovo" project was developed to standardize the methodologies for water quality management in the port areas of coastal Atlantic regions to improve the Water Frame Directive (WFD) for these specific water bodies. Under this scope, water and sediment samples were collected from five sites within the Port of Aveiro, Portugal. According to the physical and chemical parameters that were analyzed (i.e., metals, total organic carbon, polychlorinated biphenyls and polycyclic aromatic hydrocarbons), the sediments were not considered at risk based on European sediment quality laws. However, the bioassays that were performed on the sediment samples (Microtox®) and the standardized acute toxicity test using the marine rotifer, Brachionus plicatilis, on sediment elutriates revealed higher toxicity levels. The use of bioassays to assess sediment quality clearly complements more conservative approaches and highlights current gaps within the WFD. The approach presented here can be easily transferred to other port areas for more reliable water quality management.

  11. Development of Bulk Bi2+xSr3-yCa yCu 2O8+delta Superconductors by Partial-Melting Route for Fault Current Limiters Application

    Directory of Open Access Journals (Sweden)

    Bojan A. Marinkovic

    2002-06-01

    Full Text Available The production of bulk Bi2+xSr3-yCa yCu 2O8+delta (Bi-2212 superconductors for fault current limiter application was developed via a partial-melting route. Aiming high Ic (critical current, which is the essential superconducting characteristic for application of this material in the construction of Fault Current Limiters (FCL, the produced blocks have predominance of Bi-2212 phase (83 wt%, which characterizes with high values of zero and onset transport critical temperature of 92K and 97.5K, respectively. A relatively low transition width, deltaT, from the superconducting to the normal state of 5.5K, revealed a good intergrain connectivity. Consequently, current measurements on the blocks of Bi-2212 show promising Ic values of 230A and 850A for direct and alternate current, respectively. It is expected that further increases in the Ic values will depend on the elimination of an observed amorphous phase and further reduction of amount and grain sizes of secondary phases, still present in the blocks obtained by the proposed partial-melting route. This may be achieved by a further optimization of the partial-melting processing parameters.

  12. Discussion on the Limitations of Current Financial Analysis%试论现行财务分析的局限性

    Institute of Scientific and Technical Information of China (English)

    张小梅

    2011-01-01

    As the company's core operation source: finance, only to grasp the processes of enterprise's operation, sum up the past experiences, and predict its future trends, can undoubtedly become the basis of information users to make decisions. This article will analyze the framework of present financial analysis and find out the limitations, so that users can make further analysis according to its insufficient, finally make the right decision.%作为企业的核心运作源泉财务,只有很好的把握企业运作过程,并总结过去经济活动经验,预测其未来走向,对信息使用者来说无疑是作出决策的根据.文章将从对现行财务分析的框架进行剖析,找出其局限性,以便信息使用者能根据其不足作进一步分析,最终做出正确的决策判断.

  13. Monolithic quasi-sliding-mode controller for SIDO buck converter with a self-adaptive free-wheeling current level

    Institute of Scientific and Technical Information of China (English)

    Wu Xiaobo; Liu Qing; Zhao Menglian; Chen Mingyang

    2013-01-01

    An analog implementation of a novel fixed-frequency quasi-sliding-mode controller for single-inductor dual-output (SIDO) buck converter in pseudo-continuous conduction mode (PCCM) with a self-adaptive freewheeling current level (SFCL) is presented.Both small and large signal variations around the operation point are considered to achieve better transient response so as to reduce the cross-regulation of this SIDO buck converter.Moreover,an internal integral loop is added to suppress the steady-state regulation error introduced by conventional PWM-based sliding mode controllers.Instead of keeping it as a constant value,the free-wheeling current level varies according to the load condition to maintain high power efficiency and less cross-regulation at the same time.To verify the feasibility of the proposed controller,an SIDO buck converter with two regulated output voltages,1.8 V and 3.3 V,is designed and fabricated in HEJIAN 0.35 μm CMOS process.Simulation and experiment results show that the transient time of this SIDO buck converter drops to 10 μs while the cross-regulation is reduced to 0.057 mV/mA,when its first load changes from 50 to 100 mA.

  14. 用于电力系统故障电流限制器的快速合闸开关研究%Study of the Fast-Closing Switch Used for Fault Current Limiters in Power System

    Institute of Scientific and Technical Information of China (English)

    邹积岩; 董恩源; 陈金祥

    2002-01-01

    This paper presents a new type of fault current limiter (FCL) based on fast-closing switch, which is composed of a capacitor bank and a reactor in series. The main control component is a fast-closing switch connected in parallel with the capacitors, which is driven by the electromagnetic repulsion force. It can response the order within 1 ms. When fault occurs, the switch closes and the capacitors are bypassed, and the fault current is limited by the reactor. Simulation analysis and experiment show that the electromagnetic repulsion force actuator can meet the demand of fast-closing switch, it is feasible to develop the FCL with low cost and high reliability.

  15. The utility and limitations of current web-available algorithms to predict peptides recognized by CD4 T cells in response to pathogen infection #

    Science.gov (United States)

    Chaves, Francisco A.; Lee, Alvin H.; Nayak, Jennifer; Richards, Katherine A.; Sant, Andrea J.

    2012-01-01

    The ability to track CD4 T cells elicited in response to pathogen infection or vaccination is critical because of the role these cells play in protective immunity. Coupled with advances in genome sequencing of pathogenic organisms, there is considerable appeal for implementation of computer-based algorithms to predict peptides that bind to the class II molecules, forming the complex recognized by CD4 T cells. Despite recent progress in this area, there is a paucity of data regarding their success in identifying actual pathogen-derived epitopes. In this study, we sought to rigorously evaluate the performance of multiple web-available algorithms by comparing their predictions and our results using purely empirical methods for epitope discovery in influenza that utilized overlapping peptides and cytokine Elispots, for three independent class II molecules. We analyzed the data in different ways, trying to anticipate how an investigator might use these computational tools for epitope discovery. We come to the conclusion that currently available algorithms can indeed facilitate epitope discovery, but all shared a high degree of false positive and false negative predictions. Therefore, efficiencies were low. We also found dramatic disparities among algorithms and between predicted IC50 values and true dissociation rates of peptide:MHC class II complexes. We suggest that improved success of predictive algorithms will depend less on changes in computational methods or increased data sets and more on changes in parameters used to “train” the algorithms that factor in elements of T cell repertoire and peptide acquisition by class II molecules. PMID:22467652

  16. Parametic Study of the current limit within a single driver-scaletransport beam line of an induction Linac for Heavy Ion Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Prost, Lionel Robert [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    The High Current Experiment (HCX) at Lawrence Berkeley National Laboratory is part of the US program that explores heavy-ion beam as the driver option for fusion energy production in an Inertial Fusion Energy (IFE) plant. The HCX is a beam transport experiment at a scale representative of the low-energy end of an induction linear accelerator driver. The primary mission of this experiment is to investigate aperture fill factors acceptable for the transport of space-charge-dominated heavy-ion beams at high intensity (line charge density ~0.2 μC/m) over long pulse durations (4 μs) in alternating gradient focusing lattices of electrostatic or magnetic quadrupoles. This experiment is testing transport issues resulting from nonlinear space-charge effects and collective modes, beam centroid alignment and steering, envelope matching, image charges and focusing field nonlinearities, halo and, electron and gas cloud effects. We present the results for a coasting 1 MeV K+ ion beam transported through ten electrostatic quadrupoles. The measurements cover two different fill factor studies (60% and 80% of the clear aperture radius) for which the transverse phase-space of the beam was characterized in detail, along with beam energy measurements and the first halo measurements. Electrostatic quadrupole transport at high beam fill factor (~80%) is achieved with acceptable emittance growth and beam loss. We achieved good envelope control, and re-matching may only be needed every ten lattice periods (at 80% fill factor) in a longer lattice of similar design. We also show that understanding and controlling the time dependence of the envelope parameters is critical to achieving high fill factors, notably because of the injector and matching section dynamics.

  17. Maximum permissible voltage of YBCO coated conductors

    Science.gov (United States)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z.; Hong, Z.; Wang, D.; Zhou, H.; Shen, X.; Shen, C.

    2014-06-01

    Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (Ic) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the Ic degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

  18. Maximum permissible voltage of YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z. [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Hong, Z., E-mail: zhiyong.hong@sjtu.edu.cn [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Wang, D.; Zhou, H.; Shen, X.; Shen, C. [Qingpu Power Supply Company, State Grid Shanghai Municipal Electric Power Company, Shanghai (China)

    2014-06-15

    Highlights: • We examine three kinds of tapes’ maximum permissible voltage. • We examine the relationship between quenching duration and maximum permissible voltage. • Continuous I{sub c} degradations under repetitive quenching where tapes reaching maximum permissible voltage. • The relationship between maximum permissible voltage and resistance, temperature. - Abstract: Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (I{sub c}) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the I{sub c} degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

  19. Monocular Vision: Occupational Limitations and Current Standards

    Science.gov (United States)

    2011-03-01

    Kumagai, J. K., Williams, S., and Kline, D. (2005), Vision standards for aircrew: Visual acuity for pilots, (DRDC-TORONTO-CR-2005-142), Greenley ...Canadian Forces aircrew, (DRDC-TORONTO-CR-2006-255), Greenley and Associate Inc., Ottawa. Lövsund, P., Hedin, A., and Törnros, J. (1991), Effects...Williams, S., Casson, E., Brooks, J., Greenley , M., and Nadeau, J. (2003), Visual acuity standard for divers, Greenley & Associates Incorporated

  20. Orthopaedic thromboprophylaxis: limitations of current guidelines

    DEFF Research Database (Denmark)

    Warwick, D.; Dahl, O.E.; Fisher, W.D.

    2008-01-01

    research into 'evidence-based' advice. Guidelines should, in theory, benefit patient care by ensuring that every patient routinely receives the best prophylaxis; without guidelines, it is argued, patients may fail to receive treatment or be exposed to protocols which are ineffective, dangerous or expensive...

  1. Search for Same-Sign Top-Quark Pair Production at $\\sqrt{s}$ = 7 TeV and Limits on Flavour Changing Neutral Currents in the Top Sector

    CERN Document Server

    Chatrchyan, Serguei; Sirunyan, Albert M; Tumasyan, Armen; Adam, Wolfgang; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hammer, Josef; Haensel, Stephan; Hoch, Michael; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Krammer, Manfred; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rahbaran, Babak; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Teischinger, Florian; Wagner, Philipp; Waltenberger, Wolfgang; Walzel, Gerhard; Widl, Edmund; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Bansal, Sunil; Benucci, Leonardo; De Wolf, Eddi A; Janssen, Xavier; Maes, Thomas; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Devroede, Olivier; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Michael; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Charaf, Otman; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hammad, Gregory Habib; Hreus, Tomas; Marage, Pierre Edouard; Raval, Amita; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Adler, Volker; Cimmino, Anna; Costantini, Silvia; Grunewald, Martin; Klein, Benjamin; Lellouch, Jérémie; Marinov, Andrey; Mccartin, Joseph; Ryckbosch, Dirk; Thyssen, Filip; Tytgat, Michael; Vanelderen, Lukas; Verwilligen, Piet; Walsh, Sinead; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Caudron, Julien; Ceard, Ludivine; Cortina Gil, Eduardo; De Favereau De Jeneret, Jerome; Delaere, Christophe; Favart, Denis; Giammanco, Andrea; Grégoire, Ghislain; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Nuttens, Claude; Ovyn, Severine; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Schul, Nicolas; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Alves, Gilvan; Brito, Lucas; De Jesus Damiao, Dilson; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Aldá Júnior, Walter Luiz; Carvalho, Wagner; Da Costa, Eliza Melo; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Mundim, Luiz; Nogima, Helio; Oguri, Vitor; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Silva Do Amaral, Sheila Mara; Sznajder, Andre; Bernardes, Cesar Augusto; De Almeida Dias, Flavia; Tomei, Thiago; De Moraes Gregores, Eduardo; Lagana, Caio; Da Cunha Marinho, Franciole; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Darmenov, Nikolay; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Dimitrov, Anton; Hadjiiska, Roumyana; Karadzhinova, Aneliya; Kozhuharov, Venelin; Litov, Leander; Mateev, Matey; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Meng, Xiangwei; Tao, Junquan; Wang, Jian; Wang, Jian; Wang, Xianyou; Wang, Zheng; Xiao, Hong; Xu, Ming; Zang, Jingjing; Zhang, Zhen; Ban, Yong; Guo, Shuang; Guo, Yifei; Li, Wenbo; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Zhu, Bo; Zou, Wei; Cabrera, Andrés; Gomez Moreno, Bernardo; Ocampo Rios, Alberto Andres; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Lelas, Karlo; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Dzelalija, Mile; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Morovic, Srecko; Attikis, Alexandros; Galanti, Mario; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Ellithi Kamel, Ali; Khalil, Shaaban; Mahmoud, Mohammed; Hektor, Andi; Kadastik, Mario; Müntel, Mait; Raidal, Martti; Rebane, Liis; Tiko, Andres; Azzolini, Virginia; Eerola, Paula; Fedi, Giacomo; Czellar, Sandor; Härkönen, Jaakko; Heikkinen, Mika Aatos; Karimäki, Veikko; Kinnunen, Ritva; Kortelainen, Matti J; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Mäenpää, Teppo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Banzuzi, Kukka; Karjalainen, Ahti; Korpela, Arja; Tuuva, Tuure; Sillou, Daniel; Besancon, Marc; Choudhury, Somnath; Dejardin, Marc; Denegri, Daniel; Fabbro, Bernard; Faure, Jean-Louis; Ferri, Federico; Ganjour, Serguei; Gentit, François-Xavier; Givernaud, Alain; Gras, Philippe; Hamel de Monchenault, Gautier; Jarry, Patrick; Locci, Elizabeth; Malcles, Julie; Marionneau, Matthieu; Millischer, Laurent; Rander, John; Rosowsky, André; Shreyber, Irina; Titov, Maksym; Verrecchia, Patrice; Baffioni, Stephanie; Beaudette, Florian; Benhabib, Lamia; Bianchini, Lorenzo; Bluj, Michal; Broutin, Clementine; Busson, Philippe; Charlot, Claude; Dahms, Torsten; Dobrzynski, Ludwik; Elgammal, Sherif; Granier de Cassagnac, Raphael; Haguenauer, Maurice; Miné, Philippe; Mironov, Camelia; Ochando, Christophe; Paganini, Pascal; Sabes, David; Salerno, Roberto; Sirois, Yves; Thiebaux, Christophe; Wyslouch, Bolek; Zabi, Alexandre; Agram, Jean-Laurent; Andrea, Jeremy; Bloch, Daniel; Bodin, David; Brom, Jean-Marie; Cardaci, Marco; Chabert, Eric Christian; Collard, Caroline; Conte, Eric; Drouhin, Frédéric; Ferro, Cristina; Fontaine, Jean-Charles; Gelé, Denis; Goerlach, Ulrich; Greder, Sebastien; Juillot, Pierre; Karim, Mehdi; Le Bihan, Anne-Catherine; Mikami, Yoshinari; Van Hove, Pierre; Fassi, Farida; Mercier, Damien; Baty, Clement; Beauceron, Stephanie; Beaupere, Nicolas; Bedjidian, Marc; Bondu, Olivier; Boudoul, Gaelle; Boumediene, Djamel; Brun, Hugues; Chasserat, Julien; Chierici, Roberto; Contardo, Didier; Depasse, Pierre; El Mamouni, Houmani; Fay, Jean; Gascon, Susan; Ille, Bernard; Kurca, Tibor; Le Grand, Thomas; Lethuillier, Morgan; Mirabito, Laurent; Perries, Stephane; Sordini, Viola; Tosi, Silvano; Tschudi, Yohann; Verdier, Patrice; Lomidze, David; Anagnostou, Georgios; Beranek, Sarah; Edelhoff, Matthias; Feld, Lutz; Heracleous, Natalie; Hindrichs, Otto; Jussen, Ruediger; Klein, Katja; Merz, Jennifer; Mohr, Niklas; Ostapchuk, Andrey; Perieanu, Adrian; Raupach, Frank; Sammet, Jan; Schael, Stefan; Sprenger, Daniel; Weber, Hendrik; Weber, Martin; Wittmer, Bruno; Ata, Metin; Dietz-Laursonn, Erik; Erdmann, Martin; Hebbeker, Thomas; Heidemann, Carsten; Hinzmann, Andreas; Hoepfner, Kerstin; Klimkovich, Tatsiana; Klingebiel, Dennis; Kreuzer, Peter; Lanske, Dankfried; Lingemann, Joschka; Magass, Carsten; Merschmeyer, Markus; Meyer, Arnd; Papacz, Paul; Pieta, Holger; Reithler, Hans; Schmitz, Stefan Antonius; Sonnenschein, Lars; Steggemann, Jan; Teyssier, Daniel; Bontenackels, Michael; Davids, Martina; Duda, Markus; Flügge, Günter; Geenen, Heiko; Giffels, Manuel; Haj Ahmad, Wael; Heydhausen, Dirk; Hoehle, Felix; Kargoll, Bastian; Kress, Thomas; Kuessel, Yvonne; Linn, Alexander; Nowack, Andreas; Perchalla, Lars; Pooth, Oliver; Rennefeld, Jörg; Sauerland, Philip; Stahl, Achim; Thomas, Maarten; Tornier, Daiske; Zoeller, Marc Henning; Aldaya Martin, Maria; Behrenhoff, Wolf; Behrens, Ulf; Bergholz, Matthias; Bethani, Agni; Borras, Kerstin; Cakir, Altan; Campbell, Alan; Castro, Elena; Dammann, Dirk; Eckerlin, Guenter; Eckstein, Doris; Flossdorf, Alexander; Flucke, Gero; Geiser, Achim; Hauk, Johannes; Jung, Hannes; Kasemann, Matthias; Katkov, Igor; Katsas, Panagiotis; Kleinwort, Claus; Kluge, Hannelies; Knutsson, Albert; Krämer, Mira; Krücker, Dirk; Kuznetsova, Ekaterina; Lange, Wolfgang; Lohmann, Wolfgang; Mankel, Rainer; Marienfeld, Markus; Melzer-Pellmann, Isabell-Alissandra; Meyer, Andreas Bernhard; Mnich, Joachim; Mussgiller, Andreas; Olzem, Jan; Petrukhin, Alexey; Pitzl, Daniel; Raspereza, Alexei; Rosin, Michele; Schmidt, Ringo; Schoerner-Sadenius, Thomas; Sen, Niladri; Spiridonov, Alexander; Stein, Matthias; Tomaszewska, Justyna; Walsh, Roberval; Wissing, Christoph; Autermann, Christian; Blobel, Volker; Bobrovskyi, Sergei; Draeger, Jula; Enderle, Holger; Gebbert, Ulla; Görner, Martin; Hermanns, Thomas; Kaschube, Kolja; Kaussen, Gordon; Kirschenmann, Henning; Klanner, Robert; Lange, Jörn; Mura, Benedikt; Naumann-Emme, Sebastian; Nowak, Friederike; Pietsch, Niklas; Sander, Christian; Schettler, Hannes; Schleper, Peter; Schlieckau, Eike; Schröder, Matthias; Schum, Torben; Stadie, Hartmut; Steinbrück, Georg; Thomsen, Jan; Barth, Christian; Bauer, Julia; Berger, Joram; Buege, Volker; Chwalek, Thorsten; De Boer, Wim; Dierlamm, Alexander; Dirkes, Guido; Feindt, Michael; Gruschke, Jasmin; Hackstein, Christoph; Hartmann, Frank; Heinrich, Michael; Held, Hauke; Hoffmann, Karl-Heinz; Honc, Simon; Komaragiri, Jyothsna Rani; Kuhr, Thomas; Martschei, Daniel; Mueller, Steffen; Müller, Thomas; Niegel, Martin; Oberst, Oliver; Oehler, Andreas; Ott, Jochen; Peiffer, Thomas; Quast, Gunter; Rabbertz, Klaus; Ratnikov, Fedor; Ratnikova, Natalia; Renz, Manuel; Saout, Christophe; Scheurer, Armin; Schieferdecker, Philipp; Schilling, Frank-Peter; Schott, Gregory; Simonis, Hans-Jürgen; Stober, Fred-Markus Helmut; Troendle, Daniel; Wagner-Kuhr, Jeannine; Weiler, Thomas; Zeise, Manuel; Zhukov, Valery; Ziebarth, Eva Barbara; Daskalakis, Georgios; Geralis, Theodoros; Kesisoglou, Stilianos; Kyriakis, Aristotelis; Loukas, Demetrios; Manolakos, Ioannis; Markou, Athanasios; Markou, Christos; Mavrommatis, Charalampos; Ntomari, Eleni; Petrakou, Eleni; Gouskos, Loukas; Mertzimekis, Theodoros; Panagiotou, Apostolos; Saoulidou, Niki; Stiliaris, Efstathios; Evangelou, Ioannis; Foudas, Costas; Kokkas, Panagiotis; Manthos, Nikolaos; Papadopoulos, Ioannis; Patras, Vaios; Triantis, Frixos A; Aranyi, Attila; Bencze, Gyorgy; Boldizsar, Laszlo; Hajdu, Csaba; Hidas, Pàl; Horvath, Dezso; Kapusi, Anita; Krajczar, Krisztian; Sikler, Ferenc; Veres, Gabor Istvan; Vesztergombi, Gyorgy; Beni, Noemi; Molnar, Jozsef; Palinkas, Jozsef; Szillasi, Zoltan; Veszpremi, Viktor; Raics, Peter; Trocsanyi, Zoltan Laszlo; Ujvari, Balazs; Beri, Suman Bala; Bhatnagar, Vipin; Dhingra, Nitish; Gupta, Ruchi; Jindal, Monika; Kaur, Manjit; Kohli, Jatinder Mohan; Mehta, Manuk Zubin; Nishu, Nishu; Saini, Lovedeep Kaur; Sharma, Archana; Singh, Anil; Singh, Jasbir; Singh, Supreet Pal; Ahuja, Sudha; Choudhary, Brajesh C; Gupta, Pooja; Jain, Sandhya; Kumar, Ashok; Kumar, Arun; Naimuddin, Md; Ranjan, Kirti; Shivpuri, Ram Krishen; Banerjee, Sunanda; Bhattacharya, Satyaki; Dutta, Suchandra; Gomber, Bhawna; Jain, Shilpi; Khurana, Raman; Sarkar, Subir; Choudhury, Rajani Kant; Dutta, Dipanwita; Kailas, Swaminathan; Kumar, Vineet; Mehta, Pourus; Mohanty, Ajit Kumar; Pant, Lalit Mohan; Shukla, Prashant; Aziz, Tariq; Guchait, Monoranjan; Gurtu, Atul; Maity, Manas; Majumder, Devdatta; Majumder, Gobinda; Mazumdar, Kajari; Mohanty, Gagan Bihari; Saha, Anirban; Sudhakar, Katta; Wickramage, Nadeesha; Banerjee, Sudeshna; Dugad, Shashikant; Mondal, Naba Kumar; Arfaei, Hessamaddin; Bakhshiansohi, Hamed; Etesami, Seyed Mohsen; Fahim, Ali; Hashemi, Majid; Hesari, Hoda; Jafari, Abideh; Khakzad, Mohsen; Mohammadi, Abdollah; Mohammadi Najafabadi, Mojtaba; Paktinat Mehdiabadi, Saeid; Safarzadeh, Batool; Zeinali, Maryam; Abbrescia, Marcello; Barbone, Lucia; Calabria, Cesare; Colaleo, Anna; Creanza, Donato; De Filippis, Nicola; De Palma, Mauro; Fiore, Luigi; Iaselli, Giuseppe; Lusito, Letizia; Maggi, Giorgio; Maggi, Marcello; Manna, Norman; Marangelli, Bartolomeo; My, Salvatore; Nuzzo, Salvatore; Pacifico, Nicola; Pierro, Giuseppe Antonio; Pompili, Alexis; Pugliese, Gabriella; Romano, Francesco; Roselli, Giuseppe; Selvaggi, Giovanna; Silvestris, Lucia; Trentadue, Raffaello; Tupputi, Salvatore; Zito, Giuseppe; Abbiendi, Giovanni; Benvenuti, Alberto; Bonacorsi, Daniele; Braibant-Giacomelli, Sylvie; Brigliadori, Luca; Capiluppi, Paolo; Castro, Andrea; Cavallo, Francesca Romana; Cuffiani, Marco; Dallavalle, Gaetano-Marco; Fabbri, Fabrizio; Fanfani, Alessandra; Fasanella, Daniele; Giacomelli, Paolo; Giunta, Marina; Grandi, Claudio; Marcellini, Stefano; Masetti, Gianni; Meneghelli, Marco; Montanari, Alessandro; Navarria, Francesco; Odorici, Fabrizio; Perrotta, Andrea; Primavera, Federica; Rossi, Antonio; Rovelli, Tiziano; Siroli, Gianni; Travaglini, Riccardo; Albergo, Sebastiano; Cappello, Gigi; Chiorboli, Massimiliano; Costa, Salvatore; Potenza, Renato; Tricomi, Alessia; Tuve, Cristina; Barbagli, Giuseppe; Ciulli, Vitaliano; Civinini, Carlo; D'Alessandro, Raffaello; Focardi, Ettore; Frosali, Simone; Gallo, Elisabetta; Gonzi, Sandro; Lenzi, Piergiulio; Meschini, Marco; Paoletti, Simone; Sguazzoni, Giacomo; Tropiano, Antonio; Benussi, Luigi; Bianco, Stefano; Colafranceschi, Stefano; Fabbri, Franco; Piccolo, Davide; Fabbricatore, Pasquale; Musenich, Riccardo; Benaglia, Andrea; De Guio, Federico; Di Matteo, Leonardo; Gennai, Simone; Ghezzi, Alessio; Malvezzi, Sandra; Martelli, Arabella; Massironi, Andrea; Menasce, Dario; Moroni, Luigi; Paganoni, Marco; Pedrini, Daniele; Ragazzi, Stefano; Redaelli, Nicola; Sala, Silvano; Tabarelli de Fatis, Tommaso; Buontempo, Salvatore; Carrillo Montoya, Camilo Andres; Cavallo, Nicola; De Cosa, Annapaola; Fabozzi, Francesco; Iorio, Alberto Orso Maria; Lista, Luca; Merola, Mario; Paolucci, Pierluigi; Azzi, Patrizia; Bacchetta, Nicola; Bellan, Paolo; Bisello, Dario; Branca, Antonio; Carlin, Roberto; Checchia, Paolo; Dorigo, Tommaso; Dosselli, Umberto; Fanzago, Federica; Gasparini, Fabrizio; Gasparini, Ugo; Gozzelino, Andrea; Lacaprara, Stefano; Lazzizzera, Ignazio; Margoni, Martino; Mazzucato, Mirco; Meneguzzo, Anna Teresa; Nespolo, Massimo; Perrozzi, Luca; Pozzobon, Nicola; Ronchese, Paolo; Simonetto, Franco; Torassa, Ezio; Tosi, Mia; Vanini, Sara; Zotto, Pierluigi; Zumerle, Gianni; Baesso, Paolo; Berzano, Umberto; Ratti, Sergio P; Riccardi, Cristina; Torre, Paola; Vitulo, Paolo; Viviani, Claudio; Biasini, Maurizio; Bilei, Gian Mario; Caponeri, Benedetta; Fanò, Livio; Lariccia, Paolo; Lucaroni, Andrea; Mantovani, Giancarlo; Menichelli, Mauro; Nappi, Aniello; Romeo, Francesco; Santocchia, Attilio; Taroni, Silvia; Valdata, Marisa; Azzurri, Paolo; Bagliesi, Giuseppe; Bernardini, Jacopo; Boccali, Tommaso; Broccolo, Giuseppe; Castaldi, Rino; D'Agnolo, Raffaele Tito; Dell'Orso, Roberto; Fiori, Francesco; Foà, Lorenzo; Giassi, Alessandro; Kraan, Aafke; Ligabue, Franco; Lomtadze, Teimuraz; Martini, Luca; Messineo, Alberto; Palla, Fabrizio; Palmonari, Francesco; Segneri, Gabriele; Serban, Alin Titus; Spagnolo, Paolo; Tenchini, Roberto; Tonelli, Guido; Venturi, Andrea; Verdini, Piero Giorgio; Barone, Luciano; Cavallari, Francesca; Del Re, Daniele; Di Marco, Emanuele; Diemoz, Marcella; Franci, Daniele; Grassi, Marco; Longo, Egidio; Meridiani, Paolo; Nourbakhsh, Shervin; Organtini, Giovanni; Pandolfi, Francesco; Paramatti, Riccardo; Rahatlou, Shahram; Rovelli, Chiara; Amapane, Nicola; Arcidiacono, Roberta; Argiro, Stefano; Arneodo, Michele; Biino, Cristina; Botta, Cristina; Cartiglia, Nicolo; Castello, Roberto; Costa, Marco; Demaria, Natale; Graziano, Alberto; Mariotti, Chiara; Marone, Matteo; Maselli, Silvia; Migliore, Ernesto; Mila, Giorgia; Monaco, Vincenzo; Musich, Marco; Obertino, Maria Margherita; Pastrone, Nadia; Pelliccioni, Mario; Potenza, Alberto; Romero, Alessandra; Ruspa, Marta; Sacchi, Roberto; Sola, Valentina; Solano, Ada; Staiano, Amedeo; Vilela Pereira, Antonio; Belforte, Stefano; Cossutti, Fabio; Della Ricca, Giuseppe; Gobbo, Benigno; Montanino, Damiana; Penzo, Aldo; Heo, Seong Gu; Nam, Soon-Kwon; Chang, Sunghyun; Chung, Jin Hyuk; Kim, Dong Hee; Kim, Gui Nyun; Kim, Ji Eun; Kong, Dae Jung; Park, Hyangkyu; Ro, Sang-Ryul; Son, Dong-Chul; Son, Taejin; Kim, Jaeho; Kim, Jae Yool; Song, Sanghyeon; Choi, Suyong; Hong, Byung-Sik; Jo, Mihee; Kim, Hyunchul; Kim, Ji Hyun; Kim, Tae Jeong; Lee, Kyong Sei; Moon, Dong Ho; Park, Sung Keun; Sim, Kwang Souk; Choi, Minkyoo; Kang, Seokon; Kim, Hyunyong; Park, Chawon; Park, Inkyu; Park, Sangnam; Ryu, Geonmo; Choi, Young-Il; Choi, Young Kyu; Goh, Junghwan; Kim, Min Suk; Lee, Byounghoon; Lee, Jongseok; Lee, Sungeun; Seo, Hyunkwan; Yu, Intae; Bilinskas, Mykolas Jurgis; Grigelionis, Ignas; Janulis, Mindaugas; Martisiute, Dalia; Petrov, Pavel; Sabonis, Tomas; Castilla-Valdez, Heriberto; De La Cruz-Burelo, Eduard; Heredia-de La Cruz, Ivan; Lopez-Fernandez, Ricardo; Magaña Villalba, Ricardo; Sánchez-Hernández, Alberto; Villasenor-Cendejas, Luis Manuel; Carrillo Moreno, Salvador; Vazquez Valencia, Fabiola; Salazar Ibarguen, Humberto Antonio; Casimiro Linares, Edgar; Morelos Pineda, Antonio; Reyes-Santos, Marco A; Krofcheck, David; Tam, Jason; Butler, Philip H; Doesburg, Robert; Silverwood, Hamish; Ahmad, Muhammad; Ahmed, Ijaz; Asghar, Muhammad Irfan; Hoorani, Hafeez R; Khan, Wajid Ali; Khurshid, Taimoor; Qazi, Shamona; Brona, Grzegorz; Cwiok, Mikolaj; Dominik, Wojciech; Doroba, Krzysztof; Kalinowski, Artur; Konecki, Marcin; Krolikowski, Jan; Frueboes, Tomasz; Gokieli, Ryszard; Górski, Maciej; Kazana, Malgorzata; Nawrocki, Krzysztof; Romanowska-Rybinska, Katarzyna; Szleper, Michal; Wrochna, Grzegorz; Zalewski, Piotr; Almeida, Nuno; Bargassa, Pedrame; David Tinoco Mendes, Andre; Faccioli, Pietro; Ferreira Parracho, Pedro Guilherme; Gallinaro, Michele; Musella, Pasquale; Nayak, Aruna; Pela, Joao; Ribeiro, Pedro Quinaz; Seixas, Joao; Varela, Joao; Afanasiev, Serguei; Belotelov, Ivan; Golutvin, Igor; Kamenev, Alexey; Karjavin, Vladimir; Kozlov, Guennady; Lanev, Alexander; Moisenz, Petr; Palichik, Vladimir; Perelygin, Victor; Savina, Maria; Shmatov, Sergey; Smirnov, Vitaly; Volodko, Anton; Zarubin, Anatoli; Golovtsov, Victor; Ivanov, Yury; Kim, Victor; Levchenko, Petr; Murzin, Victor; Oreshkin, Vadim; Smirnov, Igor; Sulimov, Valentin; Uvarov, Lev; Vavilov, Sergey; Vorobyev, Alexey; Vorobyev, Andrey; Andreev, Yuri; Dermenev, Alexander; Gninenko, Sergei; Golubev, Nikolai; Kirsanov, Mikhail; Krasnikov, Nikolai; Matveev, Viktor; Pashenkov, Anatoli; Toropin, Alexander; Troitsky, Sergey; Epshteyn, Vladimir; Gavrilov, Vladimir; Kaftanov, Vitali; Kossov, Mikhail; Krokhotin, Andrey; Lychkovskaya, Natalia; Popov, Vladimir; Safronov, Grigory; Semenov, Sergey; Stolin, Viatcheslav; Vlasov, Evgueni; Zhokin, Alexander; Boos, Edouard; Dubinin, Mikhail; Dudko, Lev; Ershov, Alexander; Gribushin, Andrey; Kodolova, Olga; Lokhtin, Igor; Markina, Anastasia; Obraztsov, Stepan; Perfilov, Maxim; Petrushanko, Sergey; Sarycheva, Ludmila; Savrin, Viktor; Snigirev, Alexander; Andreev, Vladimir; Azarkin, Maksim; Dremin, Igor; Kirakosyan, Martin; Leonidov, Andrey; Rusakov, Sergey V; Vinogradov, Alexey; Azhgirey, Igor; Bayshev, Igor; Bitioukov, Sergei; Grishin, Viatcheslav; Kachanov, Vassili; Konstantinov, Dmitri; Korablev, Andrey; Krychkine, Victor; Petrov, Vladimir; Ryutin, Roman; Sobol, Andrei; Tourtchanovitch, Leonid; Troshin, Sergey; Tyurin, Nikolay; Uzunian, Andrey; Volkov, Alexey; Adzic, Petar; Djordjevic, Milos; Krpic, Dragomir; Milosevic, Jovan; Aguilar-Benitez, Manuel; Alcaraz Maestre, Juan; Arce, Pedro; Battilana, Carlo; Calvo, Enrique; Cepeda, Maria; Cerrada, Marcos; Chamizo Llatas, Maria; Colino, Nicanor; De La Cruz, Begona; Delgado Peris, Antonio; Diez Pardos, Carmen; Domínguez Vázquez, Daniel; Fernandez Bedoya, Cristina; Fernández Ramos, Juan Pablo; Ferrando, Antonio; Flix, Jose; Fouz, Maria Cruz; Garcia-Abia, Pablo; Gonzalez Lopez, Oscar; Goy Lopez, Silvia; Hernandez, Jose M; Josa, Maria Isabel; Merino, Gonzalo; Puerta Pelayo, Jesus; Redondo, Ignacio; Romero, Luciano; Santaolalla, Javier; Soares, Mara Senghi; Willmott, Carlos; Albajar, Carmen; Codispoti, Giuseppe; de Trocóniz, Jorge F; Cuevas, Javier; Fernandez Menendez, Javier; Folgueras, Santiago; Gonzalez Caballero, Isidro; Lloret Iglesias, Lara; Vizan Garcia, Jesus Manuel; Brochero Cifuentes, Javier Andres; Cabrillo, Iban Jose; Calderon, Alicia; Chuang, Shan-Huei; Duarte Campderros, Jordi; Felcini, Marta; Fernandez, Marcos; Gomez, Gervasio; Gonzalez Sanchez, Javier; Jorda, Clara; Lobelle Pardo, Patricia; Lopez Virto, Amparo; Marco, Jesus; Marco, Rafael; Martinez Rivero, Celso; Matorras, Francisco; Munoz Sanchez, Francisca Javiela; Piedra Gomez, Jonatan; Rodrigo, Teresa; Rodríguez-Marrero, Ana Yaiza; Ruiz-Jimeno, Alberto; Scodellaro, Luca; Sobron Sanudo, Mar; Vila, Ivan; Vilar Cortabitarte, Rocio; Abbaneo, Duccio; Auffray, Etiennette; Auzinger, Georg; Baillon, Paul; Ball, Austin; Barney, David; Bell, Alan James; Benedetti, Daniele; Bernet, Colin; Bialas, Wojciech; Bloch, Philippe; Bocci, Andrea; Bolognesi, Sara; Bona, Marcella; Breuker, Horst; Bunkowski, Karol; Camporesi, Tiziano; Cerminara, Gianluca; Christiansen, Tim; Coarasa Perez, Jose Antonio; Curé, Benoît; D'Enterria, David; De Roeck, Albert; Di Guida, Salvatore; Dupont-Sagorin, Niels; Elliott-Peisert, Anna; Frisch, Benjamin; Funk, Wolfgang; Gaddi, Andrea; Georgiou, Georgios; Gerwig, Hubert; Gigi, Dominique; Gill, Karl; Giordano, Domenico; Glege, Frank; Gomez-Reino Garrido, Robert; Gouzevitch, Maxime; Govoni, Pietro; Gowdy, Stephen; Guiducci, Luigi; Hansen, Magnus; Hartl, Christian; Harvey, John; Hegeman, Jeroen; Hegner, Benedikt; Hoffmann, Hans Falk; Honma, Alan; Innocente, Vincenzo; Janot, Patrick; Kaadze, Ketino; Karavakis, Edward; Lecoq, Paul; Lourenco, Carlos; Maki, Tuula; Malberti, Martina; Malgeri, Luca; Mannelli, Marcello; Masetti, Lorenzo; Maurisset, Aurelie; Meijers, Frans; 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Mekterovic, Darko; Volpe, Roberta; Wu, Jing-Han; Yu, Shin-Shan; Bartalini, Paolo; Chang, Paoti; Chang, You-Hao; Chang, Yu-Wei; Chao, Yuan; Chen, Kai-Feng; Hou, George Wei-Shu; Hsiung, Yee; Kao, Kai-Yi; Lei, Yeong-Jyi; Lu, Rong-Shyang; Shiu, Jing-Ge; Tzeng, Yeng-Ming; Wang, Minzu; Adiguzel, Aytul; Bakirci, Mustafa Numan; Cerci, Salim; Dozen, Candan; Dumanoglu, Isa; Eskut, Eda; Girgis, Semiray; Gokbulut, Gul; Hos, Ilknur; Kangal, Evrim Ersin; Kayis Topaksu, Aysel; Onengut, Gulsen; Ozdemir, Kadri; Ozturk, Sertac; Polatoz, Ayse; Sogut, Kenan; Sunar Cerci, Deniz; Tali, Bayram; Topakli, Huseyin; Uzun, Dilber; Vergili, Latife Nukhet; Vergili, Mehmet; Akin, Ilina Vasileva; Aliev, Takhmasib; Bilin, Bugra; Bilmis, Selcuk; Deniz, Muhammed; Gamsizkan, Halil; Guler, Ali Murat; Ocalan, Kadir; Ozpineci, Altug; Serin, Meltem; Sever, Ramazan; Surat, Ugur Emrah; Yildirim, Eda; Zeyrek, Mehmet; Deliomeroglu, Mehmet; Demir, Durmus; Gülmez, Erhan; Isildak, Bora; Kaya, Mithat; Kaya, Ozlem; Özbek, Melih; Ozkorucuklu, Suat; 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Iles, Gregory; Jarvis, Martyn; Karapostoli, Georgia; Lyons, Louis; MacEvoy, Barry C; Magnan, Anne-Marie; Marrouche, Jad; Mathias, Bryn; Nandi, Robin; Nash, Jordan; Nikitenko, Alexander; Papageorgiou, Anastasios; Pesaresi, Mark; Petridis, Konstantinos; Pioppi, Michele; Raymond, David Mark; Rogerson, Samuel; Rompotis, Nikolaos; Rose, Andrew; Ryan, Matthew John; Seez, Christopher; Sharp, Peter; Sparrow, Alex; Tapper, Alexander; Tourneur, Stephane; Vazquez Acosta, Monica; Virdee, Tejinder; Wakefield, Stuart; Wardle, Nicholas; Wardrope, David; Whyntie, Tom; Barrett, Matthew; Chadwick, Matthew; Cole, Joanne; Hobson, Peter R; Khan, Akram; Kyberd, Paul; Leslie, Dawn; Martin, William; Reid, Ivan; Teodorescu, Liliana; Hatakeyama, Kenichi; Liu, Hongxuan; Henderson, Conor; Bose, Tulika; Carrera Jarrin, Edgar; Fantasia, Cory; Heister, Arno; St John, Jason; Lawson, Philip; Lazic, Dragoslav; Rohlf, James; Sperka, David; Sulak, Lawrence; Avetisyan, Aram; Bhattacharya, Saptaparna; Chou, John Paul; Cutts, David; Ferapontov, Alexey; Heintz, Ulrich; Jabeen, Shabnam; Kukartsev, Gennadiy; Landsberg, Greg; Luk, Michael; Narain, Meenakshi; Nguyen, Duong; Segala, Michael; Sinthuprasith, Tutanon; Speer, Thomas; Tsang, Ka Vang; Breedon, Richard; Breto, Guillermo; Calderon De La Barca Sanchez, Manuel; Chauhan, Sushil; Chertok, Maxwell; Conway, John; Cox, Peter Timothy; Dolen, James; Erbacher, Robin; Friis, Evan; Ko, Winston; Kopecky, Alexandra; Lander, Richard; Liu, Haidong; Maruyama, Sho; Miceli, Tia; Nikolic, Milan; Pellett, Dave; Robles, Jorge; Salur, Sevil; Schwarz, Thomas; Searle, Matthew; Smith, John; Squires, Michael; Tripathi, Mani; Vasquez Sierra, Ricardo; Veelken, Christian; Andreev, Valeri; Arisaka, Katsushi; Cline, David; Cousins, Robert; Deisher, Amanda; Duris, Joseph; Erhan, Samim; Farrell, Chris; Hauser, Jay; Ignatenko, Mikhail; Jarvis, Chad; Plager, Charles; Rakness, Gregory; Schlein, Peter; Tucker, Jordan; Valuev, Vyacheslav; Babb, John; Chandra, Avdhesh; Clare, Robert; Ellison, John Anthony; Gary, J William; Giordano, Ferdinando; Hanson, Gail; Jeng, Geng-Yuan; Kao, Shih-Chuan; Liu, Feng; Liu, Hongliang; Long, Owen Rosser; Luthra, Arun; Nguyen, Harold; Shen, Benjamin C; Stringer, Robert; Sturdy, Jared; Sumowidagdo, Suharyo; Wilken, Rachel; Wimpenny, Stephen; Andrews, Warren; Branson, James G; Cerati, Giuseppe Benedetto; Evans, David; Golf, Frank; Holzner, André; Kelley, Ryan; Lebourgeois, Matthew; Letts, James; Mangano, Boris; Padhi, Sanjay; Palmer, Christopher; Petrucciani, Giovanni; Pi, Haifeng; Pieri, Marco; Ranieri, Riccardo; Sani, Matteo; Sharma, Vivek; Simon, Sean; Sudano, Elizabeth; Tadel, Matevz; Tu, Yanjun; Vartak, Adish; Wasserbaech, Steven; Würthwein, Frank; Yagil, Avraham; Yoo, Jaehyeok; Barge, Derek; Bellan, Riccardo; Campagnari, Claudio; D'Alfonso, Mariarosaria; Danielson, Thomas; Flowers, Kristen; Geffert, Paul; Incandela, Joe; Justus, Christopher; Kalavase, Puneeth; Koay, Sue Ann; Kovalskyi, Dmytro; Krutelyov, Vyacheslav; Lowette, Steven; Mccoll, Nickolas; Pavlunin, Viktor; Rebassoo, Finn; Ribnik, Jacob; Richman, Jeffrey; Rossin, Roberto; Stuart, David; To, Wing; Vlimant, Jean-Roch; Apresyan, Artur; Bornheim, Adolf; Bunn, Julian; Chen, Yi; Gataullin, Marat; Ma, Yousi; Mott, Alexander; Newman, Harvey B; Rogan, Christopher; Shin, Kyoungha; Timciuc, Vladlen; Traczyk, Piotr; Veverka, Jan; Wilkinson, Richard; Yang, Yong; Zhu, Ren-Yuan; Akgun, Bora; Carroll, Ryan; Ferguson, Thomas; Iiyama, Yutaro; Jang, Dong Wook; Jun, Soon Yung; Liu, Yueh-Feng; Paulini, Manfred; Russ, James; Vogel, Helmut; Vorobiev, Igor; Cumalat, John Perry; Dinardo, Mauro Emanuele; Drell, Brian Robert; Edelmaier, Christopher; Ford, William T; Gaz, Alessandro; Heyburn, Bernadette; Luiggi Lopez, Eduardo; Nauenberg, Uriel; Smith, James; Stenson, Kevin; Ulmer, Keith; Wagner, Stephen Robert; Zang, Shi-Lei; Agostino, Lorenzo; Alexander, James; Chatterjee, Avishek; Eggert, Nicholas; Gibbons, Lawrence Kent; Heltsley, Brian; Henriksson, Kristofer; Hopkins, Walter; Khukhunaishvili, Aleko; Kreis, Benjamin; Nicolas Kaufman, Gala; Patterson, Juliet Ritchie; Puigh, Darren; Ryd, Anders; Saelim, Michael; Salvati, Emmanuele; Shi, Xin; Sun, Werner; Teo, Wee Don; Thom, Julia; Thompson, Joshua; Vaughan, Jennifer; Weng, Yao; Winstrom, Lucas; Wittich, Peter; Biselli, Angela; Cirino, Guy; Winn, Dave; Abdullin, Salavat; Albrow, Michael; Anderson, Jacob; Apollinari, Giorgio; Atac, Muzaffer; Bakken, Jon Alan; Bauerdick, Lothar AT; Beretvas, Andrew; Berryhill, Jeffrey; Bhat, Pushpalatha C; Bloch, Ingo; Borcherding, Frederick; Burkett, Kevin; Butler, Joel Nathan; Chetluru, Vasundhara; Cheung, Harry; Chlebana, Frank; Cihangir, Selcuk; Cooper, William; Eartly, David P; Elvira, Victor Daniel; Esen, Selda; Fisk, Ian; Freeman, Jim; Gao, Yanyan; Gottschalk, Erik; Green, Dan; Gunthoti, Kranti; Gutsche, Oliver; Hanlon, Jim; Harris, Robert M; Hirschauer, James; Hooberman, Benjamin; Jensen, Hans; Johnson, Marvin; Joshi, Umesh; Khatiwada, Rakshya; Klima, Boaz; Kousouris, Konstantinos; Kunori, Shuichi; Kwan, Simon; Leonidopoulos, Christos; Limon, Peter; Lincoln, Don; Lipton, Ron; Lykken, Joseph; Maeshima, Kaori; Marraffino, John Michael; Mason, David; McBride, Patricia; Miao, Ting; Mishra, Kalanand; Mrenna, Stephen; Musienko, Yuri; Newman-Holmes, Catherine; O'Dell, Vivian; Pivarski, James; Pordes, Ruth; Prokofyev, Oleg; Sexton-Kennedy, Elizabeth; Sharma, Seema; Spalding, William J; Spiegel, Leonard; Tan, Ping; Taylor, Lucas; Tkaczyk, Slawek; Uplegger, Lorenzo; Vaandering, Eric Wayne; Vidal, Richard; Whitmore, Juliana; Wu, Weimin; Yang, Fan; Yumiceva, Francisco; Yun, Jae Chul; Acosta, Darin; Avery, Paul; Bourilkov, Dimitri; Chen, Mingshui; Das, Souvik; De Gruttola, Michele; Di Giovanni, Gian Piero; Dobur, Didar; Drozdetskiy, Alexey; Field, Richard D; Fisher, Matthew; Fu, Yu; Furic, Ivan-Kresimir; Gartner, Joseph; Hugon, Justin; Kim, Bockjoo; Konigsberg, Jacobo; Korytov, Andrey; Kropivnitskaya, Anna; Kypreos, Theodore; Low, Jia Fu; Matchev, Konstantin; Mitselmakher, Guenakh; Muniz, Lana; Prescott, Craig; Remington, Ronald; Rinkevicius, Aurelijus; Schmitt, Michael; Scurlock, Bobby; Sellers, Paul; Skhirtladze, Nikoloz; Snowball, Matthew; Wang, Dayong; Yelton, John; Zakaria, Mohammed; Gaultney, Vanessa; Lebolo, Luis Miguel; Linn, Stephan; Markowitz, Pete; Martinez, German; Rodriguez, Jorge Luis; Adams, Todd; Askew, Andrew; Bochenek, Joseph; Chen, Jie; Diamond, Brendan; Gleyzer, Sergei V; Haas, Jeff; Hagopian, Sharon; Hagopian, Vasken; Jenkins, Merrill; Johnson, Kurtis F; Prosper, Harrison; Quertenmont, Loic; Sekmen, Sezen; Veeraraghavan, Venkatesh; Baarmand, Marc M; Dorney, Brian; Guragain, Samir; Hohlmann, Marcus; Kalakhety, Himali; Vodopiyanov, Igor; Adams, Mark Raymond; Anghel, Ioana Maria; Apanasevich, Leonard; Bai, Yuting; Bazterra, Victor Eduardo; Betts, Russell Richard; Callner, Jeremy; Cavanaugh, Richard; Dragoiu, Cosmin; Gauthier, Lucie; Gerber, Cecilia Elena; Hofman, David Jonathan; Khalatyan, Samvel; Kunde, Gerd J; Lacroix, Florent; Malek, Magdalena; O'Brien, Christine; Silkworth, Christopher; Silvestre, Catherine; Smoron, Agata; Strom, Derek; Varelas, Nikos; Akgun, Ugur; Albayrak, Elif Asli; Bilki, Burak; Clarida, Warren; Duru, Firdevs; Lae, Chung Khim; McCliment, Edward; Merlo, Jean-Pierre; Mermerkaya, Hamit; Mestvirishvili, Alexi; Moeller, Anthony; Nachtman, Jane; Newsom, Charles Ray; Norbeck, Edwin; Olson, Jonathan; Onel, Yasar; Ozok, Ferhat; Sen, Sercan; Wetzel, James; Yetkin, Taylan; Yi, Kai; Barnett, Bruce Arnold; Blumenfeld, Barry; Bonato, Alessio; Eskew, Christopher; Fehling, David; Giurgiu, Gavril; Gritsan, Andrei; Guo, Zijin; Hu, Guofan; Maksimovic, Petar; Rappoccio, Salvatore; Swartz, Morris; Tran, Nhan Viet; Whitbeck, Andrew; Baringer, Philip; Bean, Alice; Benelli, Gabriele; Grachov, Oleg; Kenny Iii, Raymond Patrick; Murray, Michael; Noonan, Daniel; Sanders, Stephen; Wood, Jeffrey Scott; Zhukova, Victoria; Barfuss, Anne-fleur; Bolton, Tim; Chakaberia, Irakli; Ivanov, Andrew; Khalil, Sadia; Makouski, Mikhail; Maravin, Yurii; Shrestha, Shruti; Svintradze, Irakli; Wan, Zongru; Gronberg, Jeffrey; Lange, David; Wright, Douglas; Baden, Drew; Boutemeur, Madjid; Eno, Sarah Catherine; Ferencek, Dinko; Gomez, Jaime; Hadley, Nicholas John; Kellogg, Richard G; Kirn, Malina; Lu, Ying; Mignerey, Alice; Rossato, Kenneth; Rumerio, Paolo; Santanastasio, Francesco; Skuja, Andris; Temple, Jeffrey; Tonjes, Marguerite; Tonwar, Suresh C; Twedt, Elizabeth; Alver, Burak; Bauer, Gerry; Bendavid, Joshua; Busza, Wit; Butz, Erik; Cali, Ivan Amos; Chan, Matthew; Dutta, Valentina; Everaerts, Pieter; Gomez Ceballos, Guillelmo; Goncharov, Maxim; Hahn, Kristan Allan; Harris, Philip; Kim, Yongsun; Klute, Markus; Lee, Yen-Jie; Li, Wei; Loizides, Constantinos; Luckey, Paul David; Ma, Teng; Nahn, Steve; Paus, Christoph; Ralph, Duncan; Roland, Christof; Roland, Gunther; Rudolph, Matthew; Stephans, George; Stöckli, Fabian; Sumorok, Konstanty; Sung, Kevin; Velicanu, Dragos; Wenger, Edward Allen; Wolf, Roger; Xie, Si; Yang, Mingming; Yilmaz, Yetkin; Yoon, Sungho; Zanetti, Marco; Cooper, Seth; Cushman, Priscilla; Dahmes, Bryan; De Benedetti, Abraham; Dudero, Phillip Russell; Franzoni, Giovanni; Gude, Alexander; Haupt, Jason; Klapoetke, Kevin; Kubota, Yuichi; Mans, Jeremy; Pastika, Nathaniel; Rekovic, Vladimir; Rusack, Roger; Sasseville, Michael; Singovsky, Alexander; Tambe, Norbert; Cremaldi, Lucien Marcus; Godang, Romulus; Kroeger, Rob; Perera, Lalith; Rahmat, Rahmat; Sanders, David A; Summers, Don; Bloom, Kenneth; Bose, Suvadeep; Butt, Jamila; Claes, Daniel R; Dominguez, Aaron; Eads, Michael; Jindal, Pratima; Keller, Jason; Kelly, Tony; Kravchenko, Ilya; Lazo-Flores, Jose; Malbouisson, Helena; Malik, Sudhir; Snow, Gregory R; Baur, Ulrich; Godshalk, Andrew; Iashvili, Ia; Jain, Supriya; Kharchilava, Avto; Kumar, Ashish; Shipkowski, Simon Peter; Smith, Kenneth; Alverson, George; Barberis, Emanuela; Baumgartel, Darin; Boeriu, Oana; Chasco, Matthew; Reucroft, Steve; Swain, John; Trocino, Daniele; Wood, Darien; Zhang, Jinzhong; Anastassov, Anton; Kubik, Andrew; Odell, Nathaniel; 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Zielinski, Marek; Bhatti, Anwar; Ciesielski, Robert; Demortier, Luc; Goulianos, Konstantin; Lungu, Gheorghe; Malik, Sarah; Mesropian, Christina; Atramentov, Oleksiy; Barker, Anthony; Duggan, Daniel; Gershtein, Yuri; Gray, Richard; Halkiadakis, Eva; Hidas, Dean; Hits, Dmitry; Lath, Amitabh; Panwalkar, Shruti; Patel, Rishi; Rose, Keith; Schnetzer, Steve; Somalwar, Sunil; Stone, Robert; Thomas, Scott; Cerizza, Giordano; Hollingsworth, Matthew; Spanier, Stefan; Yang, Zong-Chang; York, Andrew; Eusebi, Ricardo; Flanagan, Will; Gilmore, Jason; Gurrola, Alfredo; Kamon, Teruki; Khotilovich, Vadim; Montalvo, Roy; Osipenkov, Ilya; Pakhotin, Yuriy; Safonov, Alexei; Sengupta, Sinjini; Tatarinov, Aysen; Toback, David; Weinberger, Michael; Akchurin, Nural; Bardak, Cemile; Damgov, Jordan; Jeong, Chiyoung; Kovitanggoon, Kittikul; Lee, Sung Won; Libeiro, Terence; Mane, Poonam; Roh, Youn; Sill, Alan; Volobouev, Igor; Wigmans, Richard; Yazgan, Efe; Appelt, Eric; Brownson, Eric; Engh, Daniel; Florez, Carlos; Gabella, William; Issah, Michael; Johns, Willard; Kurt, Pelin; Maguire, Charles; Melo, Andrew; Sheldon, Paul; Snook, Benjamin; Tuo, Shengquan; Velkovska, Julia; Arenton, Michael Wayne; Balazs, Michael; Boutle, Sarah; Cox, Bradley; Francis, Brian; Goodell, Joseph; Hirosky, Robert; Ledovskoy, Alexander; Lin, Chuanzhe; Neu, Christopher; Yohay, Rachel; Gollapinni, Sowjanya; Harr, Robert; Karchin, Paul Edmund; Lamichhane, Pramod; Mattson, Mark; Milstène, Caroline; Sakharov, Alexandre; Anderson, Michael; Bachtis, Michail; Bellinger, James Nugent; Carlsmith, Duncan; Dasu, Sridhara; Efron, Jonathan; Gray, Lindsey; Grogg, Kira Suzanne; Grothe, Monika; Hall-Wilton, Richard; Herndon, Matthew; Hervé, Alain; Klabbers, Pamela; Klukas, Jeffrey; Lanaro, Armando; Lazaridis, Christos; Leonard, Jessica; Loveless, Richard; Mohapatra, Ajit; Ojalvo, Isabel; Reeder, Don; Ross, Ian; Savin, Alexander; Smith, Wesley H; Swanson, Joshua; Weinberg, Marc

    2011-01-01

    An inclusive search for same-sign top-quark pair production in pp collisions at sqrt(s) = 7 TeV is performed using a data sample recorded with the CMS detector in 2010, corresponding to an integrated luminosity of 35 inverse picobarns. This analysis is motivated by recent studies of p p-bar to t t-bar reporting mass-dependent forward-backward asymmetries larger than expected from the standard model. These asymmetries could be due to Flavor Changing Neutral Currents (FCNC) in the top sector induced by t-channel exchange of a massive neutral vector boson (Z'). Models with such a Z' also predict enhancement of same-sign top-pair production in pp or p p-bar collisions. Limits are set as a function of the Z'mass and its couplings to u and t quarks. These limits disfavour the FCNC interpretation of the Tevatron results.

  2. Search for same-sign top-quark pair production at sqrt(s) = 7 TeV and limits on flavour changing neutral currents in the top sector

    Energy Technology Data Exchange (ETDEWEB)

    Chatrchyan, Serguei [Yerevan Physics Inst. (Armenia); et al.

    2011-08-01

    An inclusive search for same-sign top-quark pair production in pp collisions at sqrt(s) = 7 TeV is performed using a data sample recorded with the CMS detector in 2010, corresponding to an integrated luminosity of 35 inverse picobarns. This analysis is motivated by recent studies of p p-bar to t t-bar reporting mass-dependent forward-backward asymmetries larger than expected from the standard model. These asymmetries could be due to Flavor Changing Neutral Currents (FCNC) in the top sector induced by t-channel exchange of a massive neutral vector boson (Z'). Models with such a Z' also predict enhancement of same-sign top-pair production in pp or p p-bar collisions. Limits are set as a function of the Z' mass and its couplings to u and t quarks. These limits disfavour the FCNC interpretation of the Tevatron results.

  3. Observation of a new turbulence-driven limit-cycle state in H-modes with lower hybrid current drive and lithium-wall conditioning in the EAST superconducting tokamak

    DEFF Research Database (Denmark)

    Wang, H.Q.; Xu, G.S.; Guo, H.Y.;

    2012-01-01

    -frequency oscillation, termed a limit-cycle state, appears at the edge during the quiescent phase with good energy and particle confinement. Detailed measurements by edge Langmuir probes show modulation interaction and strong three-wave coupling between the low-frequency oscillations and high-frequency-broadband (80......The first high confinement H-mode plasma has been obtained in the Experimental Advanced Superconducting Tokamak (EAST) with about 1 MW lower hybrid current drive after wall conditioning by lithium evaporation and real-time injection of Li powder. Following the L–H transition, a small-amplitude, low....... And the measurements demonstrate that the energy gain of zonal flows is of the same order as the energy loss of turbulence. This strongly suggests the interactions between zonal flows and high-frequency turbulences at the pedestal during the limit-cycle state....

  4. 大容量高速限流开关的设计与试验研究%Design and Test Study of Large Capacity High Speed Current Limit Switch

    Institute of Scientific and Technical Information of China (English)

    李健; 朱峰

    2011-01-01

    针对现有保护设备难以满足大容量电力系统短路保护要求的问题,研制了一种基于爆炸活塞式高速开断器和灭弧熔断器的混合型限流保护装置,设计了额定640V/2500A的工程样机,并进行了高速开断器的分断试验和整机的限流试验。试验结果表明,该保护装置限流效果显著,全分断时fHJ仪为2.5ms,大大提高了电力系统的安全性。%Aiming at the problem that the existing protection equipment is difficult to meet large capacity power system short circuit protective requirements problem, this paper researched a kind of high speed break-off device based on explosive piston type and arc blow-out fuse mixed type, current limit protection device, designing rated voltage 640 V/2 500 A engineering sample machine. The break-off test and whole machine current limit test were carried out for high speed breaker. Test result shows that the protective device current limit effect is obvious and the total break-offtime is only 2.5 ms, which greatly raises safety of the power system.

  5. Start-stop Control Strategy for UPFC with Fault Current Limiting%限流式统一潮流控制器的启停控制策略

    Institute of Scientific and Technical Information of China (English)

    沈忱; 江道灼; 吕文韬; 王玉芬

    2013-01-01

    限流式统一潮流控制器(UPFC)可以有效避免串联变换器因系统短路电流冲击而损毁。针对限流式UPFC已有功率控制策略的不足,建立了含限流式 UPFC 的系统模型,提出了基于线路电流控制的功率控制策略。分析了限流式UPFC的启停过程,给出了完整的启停控制方案。启动阶段接入限流电阻以防止直流电容充电电流过大而导致过电压和过电流损坏。停机时通过并联变换器释放直流电容的一部分能量从而降低放电电阻的设计要求。PSCAD/EMTDC软件的建模与仿真结果证明了基于线路电流控制的限流式UPFC功率控制策略具有良好的动态和稳态性能,同时也验证了启停控制方案的合理性和有效性。%The unified power flow controller with fault current limiting (UPFC-FCL) can effectively protect series converter from being damaged by short circuit current.In view of the inadequacy of existing power control strategies for UPFC-FCL,a power system model with UPFC-FCL is developed,and a power control strategy based on line current control is proposed.The start-stop process of UPFC-FCL is analyzed,then a complete start-stop control scheme is proposed.In the start process,the charging rate of DC capacitor is limited by current-limiting resistance,which prevents overvoltage or overcurrent of the equipment.In the stop process,the design requirements of discharge resistance can be reduced as the energy of DC capacitance is partly released through the shunt converter.PSCAD/EMTDC simulation results demonstrate that the UPFC-FCL power control strategy based on line current control has good dynamic and steady performance,and the start-stop control scheme is rational and effective.

  6. 变频器限流电阻旁路开关的选用探讨%Research on selection of bypass switch for current-limit resistor of inverter

    Institute of Scientific and Technical Information of China (English)

    席志刚

    2016-01-01

    介绍了目前固态继电器、交流接触器、单极直流接触器等变频器的限流电阻保护用旁路开关的具体用法和选用习惯,讨论解决了在使用单极直流接触器时绝缘电压选择、接触器并联使用及额定工作电压选择等相关问题。%The usages and the selection trend of the bypass switches for the current-limit resistors of the solid-state relays, AC contactors and single-polar DC contactors of the inverters are presented. The three problems and the relevant solutions on the insulation voltage, the parallel connection and the rated working voltage for the single-polar DC contactors using are also given.

  7. Computer controlled performance mapping of thermionic converters: effect of collector, guard-ring potential imbalances on the observed collector current-density, voltage characteristics and limited range performance map of an etched-rhenium, niobium planar converter

    Science.gov (United States)

    Manista, E. J.

    1972-01-01

    The effect of collector, guard-ring potential imbalance on the observed collector-current-density J, collector-to-emitter voltage V characteristic was evaluated in a planar, fixed-space, guard-ringed thermionic converter. The J,V characteristic was swept in a period of 15 msec by a variable load. A computerized data acquisition system recorded test parameters. The results indicate minimal distortion of the J,V curve in the power output quadrant for the nominal guard-ring circuit configuration. Considerable distortion, along with a lowering of the ignited-mode striking voltage, was observed for the configuration with the emitter shorted to the guard ring. A limited-range performance map of an etched-rhenium, niobium, planar converter was obtained by using an improved computer program for the data acquisition system.

  8. Fabrication of Limiting-Current Type Oxygen Sensors by a Technology of Multilayered Cofiring%极限电流型氧传感器的多层共烧制备

    Institute of Scientific and Technical Information of China (English)

    沈杰; 简家文; 章东兴; 汪益

    2009-01-01

    A thin-film limiting-current type oxygen sensor using 5 mol% yttrium stabilized zirconia(5YSZ) was developed successfully through the technology of tape casting. It was made from tape-casting layers by screen printing,stacking hot pressing and multilayered cofiring process. Meanwhile the physical characteristics were investigated by thermal expansion instrument, SEM and digital microscope. The response time and I-V curve of oxygen sensor sample were tested at 923 K in a mixture of the N_2-O_2 with the oxygen concentration between 1100×10~(-6) and 90%. The result distinctly shows that stable current platforms of the sensors prepared by multilayered cofiring are formed in the scope of the oxygen concentration mentioned previously,and a good linear relationship between the limiting current and oxygen concentration is illustrated according to Normal diffusion mechanisms; Simultaneously it is indicated that the sensors have good repeatability at 923 K with the oxygen concentration varying from 5. 06% to 21. 24% and the response time is within 1 second.%实验采用5%摩尔钇含量氧化锆流延生瓷片,经过厚膜丝网印刷,叠片热压,多层共烧制备了氧化锆极限电流型氧传感器;通过热膨胀仪、数字显微镜、扫描电子显微镜(SEM)等手段对其进行了物理性能的表征,并对该传感器在923 K温度氧浓度1100×10~(-6)~90%范围内的气敏特性、响应时间等进行了输出特性的研究.实验结果表明共烧制备的传感器在上述氧浓度范围内具有较好的电流平台,且极限电流与氧浓度存在正常扩散模型具有的线性关系;工作温度在923 K,氧浓度在21.24%和5.06%之间变化对应的传感器响应时间呈现出较好的重复性,且均在1 s以内.

  9. Research on current situation and establishing methods of pesticide maximum residue limits in food%食品中农药最大残留限量的现状及制定方法

    Institute of Scientific and Technical Information of China (English)

    杨艳红; 姜兆兴; 赵敏

    2015-01-01

    食品中农药的最大残留限量(MRLs)是保障食品质量安全的重要立法依据,也是指导食品和农产品等生产的关键技术指标。MRLs的制定方法不仅影响农产品行业的持续发展,而且还对提高我国农产品行业的国际竞争力起到积极作用。本文简要介绍目前国内外 MRLs 标准的现状、涉及农药的种类以及制定农药最大残留限量的依据,概述了基于田间实验数据制定最大残留限量的方法,并且比较了国际上欧盟(EU)、北美自由贸易协定(NAFTA)成员国、经济合作与发展组织(OECD)及农药残留联席会议(JMPR)的限量制定方案。%Pesticide maximum residue limit is a critical legislative basis for food safety and a key technical indicator to instruct food and agro-products. The establishing methods for MRLs not only influence the sustainable development of agricultural industry, but also play an actively role on the improvement of international competitiveness of Chinese agricultural industry. The current situation and principles employed to establish maximum residue limits were briefly introduced in this paper. The methods derived from field trials were summarized for setting MRLs. Meanwhile, the calculation methods proposed by European Union (EU), members of North American Free Trade Agreement (NAFTA), Organization for Economic Cooperation and Development (OECD) and Joint Meeting of Pesticide Residues (JMPR) were compared.

  10. 大容量永磁饱和型故障限流器参数设计与优化%Parameter Design and Optimization Methodology for Large Capacity Applications of Permanent-magnet-biased Saturation Based Fault Current Limiter

    Institute of Scientific and Technical Information of China (English)

    邹亮; 李庆民; 刘洪顺; 张黎

    2011-01-01

    A straight-line type topology was employed for permanent-magnet-biased saturation based fault current limiter (PMFCL) to meet large capacity application requirements. By virtue of three basic variables of saturation depth ratio, inductance ratio and inductance sum, an algorithm for structural parameters design was established on the basis of equivalent magnetic circuit method. Through analysis of the iron-core's operational points, the optimization of the structural parameters was equivalently transformed to optimization of the three independent variables, which can also be considered as the optimization of three key points on the I-Be curve of iron-core. A solid foundation for optimal structural parameters was laid in view of all of the above work. The parameter optimization algorithm was applied to an actual case study in 110 kV system, and a magnetic field-circuit coupled simulation model was created with Maxwell-2D regarding the novel PMFCL topology, which verified the effectiveness of the proposed methodology and the optimized results.%为适应大容量应用需求,针对一种直线式永磁饱和型故障限流器(permanent-magnet-biased saturation based fault current limiter,PMFCL)磁拓扑结构,基于等效磁路法建立了以饱和深度比、电感比与电感和为基本变量的结构参数设计算法,并通过分析铁心上工作点的变化规律,将PMFCL结构参数优化转化为对3个独立变量的优化,即对铁心I-Be曲线上3个关键点的优化问题,为获得最优结构参数奠定了算法基础.将参数优化算法应用于110 kV系统设计实例,并基于Maxwell-2D软件建立了直线式PMFCL的场一路耦合仿真模型,验证了算法及优化结构参数的有效性.

  11. Limited Neutrality

    DEFF Research Database (Denmark)

    Nielsen, Morten Ebbe Juul

    2006-01-01

    Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."......Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."...

  12. Limiting Skepticism

    DEFF Research Database (Denmark)

    Hendricks, Vincent Fella; Symons, John

    2011-01-01

    Skeptics argue that the acquisition of knowledge is impossible given the standing possibility of error. We present the limiting convergence strategy for responding to skepticism and discuss the relationship between conceivable error and an agent’s knowledge in the limit. We argue that the skeptic...

  13. Limited Neutrality

    DEFF Research Database (Denmark)

    Nielsen, Morten Ebbe Juul

    2006-01-01

    Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."......Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."...

  14. Inverse Limits

    CERN Document Server

    Ingram, WT

    2012-01-01

    Inverse limits provide a powerful tool for constructing complicated spaces from simple ones. They also turn the study of a dynamical system consisting of a space and a self-map into a study of a (likely more complicated) space and a self-homeomorphism. In four chapters along with an appendix containing background material the authors develop the theory of inverse limits. The book begins with an introduction through inverse limits on [0,1] before moving to a general treatment of the subject. Special topics in continuum theory complete the book. Although it is not a book on dynamics, the influen

  15. Current investigations into the genotoxicity of zinc oxide and silica nanoparticles in mammalian models in vitro and in vivo: carcinogenic/genotoxic potential, relevant mechanisms and biomarkers, artifacts, and limitations

    Directory of Open Access Journals (Sweden)

    Kwon JY

    2014-12-01

    Full Text Available Jee Young Kwon,1,* Preeyaporn Koedrith,2,* Young Rok Seo1 1Department of Life Science, Institute of Environmental Medicine, Dongguk University, Seoul, Republic of Korea; 2Faculty of Environment and Resource Studies, Mahidol University, Phuttamonthon District, NakhonPathom, Thailand *These authors contributed equally to this work and should be considered as co-first authors Abstract: Engineered nanoparticles (NPs are widely used in many sectors, such as food, medicine, military, and sport, but their unique characteristics may cause deleterious health effects. Close attention is being paid to metal NP genotoxicity; however, NP genotoxic/carcinogenic effects and the underlying mechanisms remain to be elucidated. In this review, we address some metal and metal oxide NPs of interest and current genotoxicity tests in vitro and in vivo. Metal NPs can cause DNA damage such as chromosomal aberrations, DNA strand breaks, oxidative DNA damage, and mutations. We also discuss several parameters that may affect genotoxic response, including physicochemical properties, widely used assays/end point tests, and experimental conditions. Although potential biomarkers of nanogenotoxicity or carcinogenicity are suggested, inconsistent findings in the literature render results inconclusive due to a variety of factors. Advantages and limitations related to different methods for investigating genotoxicity are described, and future directions and recommendations for better understanding genotoxic potential are addressed. Keywords: carcinogenicity, exposure assessment, genotoxicity, nanoparticles, risk evaluation

  16. Surge Current Test of Fault Current Limiter Thyristor Valve in the 500 kV East China Power Grid%华东电网500kV故障电流限制器晶闸管阀浪涌电流试验方法研究

    Institute of Scientific and Technical Information of China (English)

    袁洪亮; 任孟干; 赵东旭; 昃萌; 柴斌

    2011-01-01

    Instead of the conventional method of half fundamental frequency cycle surge current, a test method of continuous fundamental frequency cycles surge current for thyristors was presented. The method was validated by a circuit simulation with mathematics modeling; and the circuit simulation was compared with the result from surge tests on the sample thyristors. The practical value of the selected thyristor through the model of instantaneous junction temperature rise was validated. Based on an application project, the method for simulation and experiment of thyristor valves was presented, and the test results were provided to support the selection and design of thyristor valves. The thyristor valves used in the fault current limiter were simulated with the method of instantaneous junction temperature rise in the 500 kV East China Power Grid. Combining the results of simulation, experiments and artificial ground short circuit test, the paper validates the reliability of 6-inch thyristor in the fault current limiter project.%针对晶闸管浪涌电流试验采用半波10ms浪涌试验方式,提出连续多周波浪涌的试验方法,通过数学建模对试验方法进行仿真研究,同时与晶闸管样品浪涌试验结果进行分析对比,验证了通过晶闸管结温温升系列模型仿真计算来选择晶闸管阀的实际指导价值.从实际工程角度出发,给出晶闸管阀仿真和试验的方法,为晶闸管阀的选择和设计提供了试验结果支持.对华东500kV故障电流限制器示范工程用晶闸管阀进行结温温升仿真,及人工接地短路试验的结果分析,验证了6英寸晶闸管在故障电流限制器工程中应用的可靠性.

  17. THE IDEA IS TO USEMODIS IN CONJUNCTION WITH THE CURRENT LIMITED LANDSAT CAPABILITY, COMMERCIAL SATELLITES, ANDUNMANNED AERIAL VEHICLES (UAV), IN A MULTI-STAGE APPROACH TO MEET EPA INFORMATION NEEDS.REMOTE SENSING OVERVIEW: EPA CAPABILITIES, PRIORITY AGENCY APPLICATIONS, SENSOR/AIRCRAFT CAPABILITIES, COST CONSIDERATIONS, SPECTRAL AND SPATIAL RESOLUTIONS, AND TEMPORAL CONSIDERATIONS

    Science.gov (United States)

    EPA remote sensing capabilities include applied research for priority applications and technology support for operational assistance to clients across the Agency. The idea is to use MODIS in conjunction with the current limited Landsat capability, commercial satellites, and Unma...

  18. Current and other data from fixed platforms from the SW Atlantic (limit-20 W) as part of the International Decade of Ocean Exploration / International Ocean Studies / First Dynamic Response and Kinematics Experiment in the Drake Passage (IDOE/ISOS/FDRAKE) from 16 February 1976 to 23 January 1977 (NODC Accession 7800683)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current and other data were collected from fixed platforms in the SW Atlantic (limit-20 W) from 16 February 1976 to 23 January 1977. Data were collected by Oregon...

  19. THE IDEA IS TO USEMODIS IN CONJUNCTION WITH THE CURRENT LIMITED LANDSAT CAPABILITY, COMMERCIAL SATELLITES, ANDUNMANNED AERIAL VEHICLES (UAV), IN A MULTI-STAGE APPROACH TO MEET EPA INFORMATION NEEDS.REMOTE SENSING OVERVIEW: EPA CAPABILITIES, PRIORITY AGENCY APPLICATIONS, SENSOR/AIRCRAFT CAPABILITIES, COST CONSIDERATIONS, SPECTRAL AND SPATIAL RESOLUTIONS, AND TEMPORAL CONSIDERATIONS

    Science.gov (United States)

    EPA remote sensing capabilities include applied research for priority applications and technology support for operational assistance to clients across the Agency. The idea is to use MODIS in conjunction with the current limited Landsat capability, commercial satellites, and Unma...

  20. Current meter components and other data from FIXED PLATFORMS from the NW Atlantic (limit-40 W) and others locations as part of the Coupled Ocean-Atmosphere Response Experiment (COARE) and other projects from 26 February 1984 to 01 June 1986 (NODC Accession 9100048)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter components data were collected from FIXED PLATFORMS in the NW Atlantic (limit-40 W) and others locations from 26 February 1984 to 01 June 1986. Data...

  1. Physical and other data from CTD casts, XBT casts, current meters, and other instruments from the SHOYO and other platforms from the NE Pacific (limit-180) and other locations by the Japanese Hydrographic Office and the Maritime Safety Agency; Hydrographic Division from 16 January 1993 to 01 December 1995 (NODC Accession 9600079)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical and other data from CTD casts, XBT casts, current meters, and other instruments from the SHOYO and other platforms from the NE Pacific (limit-180) and other...

  2. Hydrographic, current profile, and other data from STD and other instruments from the NW Pacific (limit-180) from the YAQUINA and other platforms as part of the International Decade of Ocean Exploration / Cooperative Investigations of the Caribbean and Adjacent Regions (IDOE/CICAR) and related projects from 31 July 1972 to 25 August 1972 (NODC Accession 7500531)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hydrographic, current profiles, and other data were collected from STD and other instruments in the NW Pacific (limit-180) from the YAQUINA from 31 July 1972 to 25...

  3. Short circuit current limiting strategies optimization based on parallel immune particle swarm algorithm%基于并行免疫粒子群算法的限流措施优化

    Institute of Scientific and Technical Information of China (English)

    张思; 黄民翔; 陈丽莉

    2012-01-01

    According to the discontinuous and nonlinear characteristics of the optimization of short circuit current limiting strategies for power system, a parallel immune particle swarm optimization algorithm is proposed. The algorithm combines self-regulation mechanism of immune algorithm with particle swarm optimization algorithm, and adopts the selection mechanism based on particle similarity to ensure the diversity of particles in the optimization process. The introduction of vaccination concept according to the characteristics of particle code effectively eliminates the chance of missing the best pieces of particles, thus both convergence accuracy and convergence rate can be ensured. This paper achieves parallelism of immune particle swarm optimization algorithms on Matlab parallel computing platform. The results show that the proposed algorithm has strong global optimization ability and convergence stability, and optimization time is short, so it is practicable.%针对电力系统限流措施优化问题不连续、非线性的特点,提出一种并行免疫粒子群算法.该算法将免疫算法的自我调节机制引入粒子群算法,采用基于粒子相似度的选择机制,保证优化过程中粒子的多样性.根据粒子编码的特点引入疫苗接种概念,有效减少了粒子最优片段丢失的概率,保证算法的收敛精度和收敛速度.并在Matlab并行计算平台上实现免疫粒子群算法的并行化.算例表明该算法具有较强的全局优化能力和收敛稳定性,且计算时间短,有较强的实用意义.

  4. Characteristics of the magnetic flux-offset type FCL by switching component

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Byung Ik [Dongkang Collage, Gwangju (Korea, Republic of); Choi, Hyo Sang [Chosun University, Gwangju (Korea, Republic of)

    2016-06-15

    The study of superconducting fault current limiter (SFCL) is continuously being studied as a countermeasure for reducing fault-current in the power system. When the fault occurred in the power system, the fault-current was limited by the generated impedance of SFCLs. The operational characteristics of the flux-offset type SFCL according to turn ratios between the primary and the secondary winding of a reactor were compared in this study. We connected the secondary core to a superconductor and a SCR switch in series in the suggested structure. The fault current in the primary and the secondary winding of the reactor and the voltage of the superconductor on the secondary were measured and compared. The results showed that the fault current in the load line was the lowest and the voltage applied at both ends of the superconductor was also low when the secondary winding of the reactor had lower turn ratio than the primary. It was confirmed based on these results that the turn ratio of the secondary winding of the reactor must be designed to be lower than that of the primary winding to reduce the burden of the superconductor and to lower the fault current. Also, the suggested structure could increase the duration of the limited current by limiting the continuous current after the first half cycle from the fault with the fault current limiter.

  5. Limiting Output

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    To protect the environment and its domestic industries from excess production,China must guide the non-ferrous metal industry In an effort to save energy and curb carbon emissions, in addition to reorganizing a currently disorderly industry, China will continue to control the

  6. Feasibility analysis of a novel hybrid-type superconducting circuit breaker in multi-terminal HVDC networks

    Science.gov (United States)

    Khan, Umer Amir; Lee, Jong-Geon; Seo, In-Jin; Amir, Faisal; Lee, Bang-Wook

    2015-11-01

    Voltage source converter-based HVDC systems (VSC-HVDC) are a better alternative than conventional thyristor-based HVDC systems, especially for developing multi-terminal HVDC systems (MTDC). However, one of the key obstacles in developing MTDC is the absence of an adequate protection system that can quickly detect faults, locate the faulty line and trip the HVDC circuit breakers (DCCBs) to interrupt the DC fault current. In this paper, a novel hybrid-type superconducting circuit breaker (SDCCB) is proposed and feasibility analyses of its application in MTDC are presented. The SDCCB has a superconducting fault current limiter (SFCL) located in the main current path to limit fault currents until the final trip signal is received. After the trip signal the IGBT located in the main line commutates the current into a parallel line where DC current is forced to zero by the combination of IGBTs and surge arresters. Fault simulations for three-, four- and five-terminal MTDC were performed and SDCCB performance was evaluated in these MTDC. Passive current limitation by SFCL caused a significant reduction of fault current interruption stress in the SDCCB. It was observed that the DC current could change direction in MTDC after a fault and the SDCCB was modified to break the DC current in both the forward and reverse directions. The simulation results suggest that the proposed SDCCB could successfully suppress the DC fault current, cause a timely interruption, and isolate the faulty HVDC line in MTDC.

  7. Modeling Complex Time Limits

    Directory of Open Access Journals (Sweden)

    Oleg Svatos

    2013-01-01

    Full Text Available In this paper we analyze complexity of time limits we can find especially in regulated processes of public administration. First we review the most popular process modeling languages. There is defined an example scenario based on the current Czech legislature which is then captured in discussed process modeling languages. Analysis shows that the contemporary process modeling languages support capturing of the time limit only partially. This causes troubles to analysts and unnecessary complexity of the models. Upon unsatisfying results of the contemporary process modeling languages we analyze the complexity of the time limits in greater detail and outline lifecycles of a time limit using the multiple dynamic generalizations pattern. As an alternative to the popular process modeling languages there is presented PSD process modeling language, which supports the defined lifecycles of a time limit natively and therefore allows keeping the models simple and easy to understand.

  8. Application of robotic surgical system in the treatment of liver neoplasms:Current status and limitations%机器人肝切除应用价值与评价

    Institute of Scientific and Technical Information of China (English)

    王晓颖

    2016-01-01

    Robotic platforms has overcome many of the limitations of conventional laparoscopic surgery. The indications for robotic liver surgery include all the indications for laparoscopic liver surgery and comprise both benign lesions and malignancies. The current literatures and data demonstrate that robotic liver surgery is a feasible and safe option. In properly selected patients, robotic approach associated with less invasion and fast recovery compared to open approach. Both robotic and laparoscopic approaches are similar in perioperative outcomes and long-term oncologic outcomes. Robotic approach may increase percentage of major hepatectomies in a purely minimally invasive fashion, facilitate the resection of superior and posterior liver tumors, and provide better precision in intracorporeal biliary and vascular reconstruction. However, robotic approach has significantly longer operative time and higher cost. Since the case number of available study was probably too small to allow firm conclusions,large randomized studies are needed to compare robotic liver surgery with conventional laparoscopy and open surgery.%机器人手术系统克服了传统腹腔镜技术的内在缺陷,已应用于各种良、恶性肝脏肿瘤手术中。机器人肝脏手术涵盖了所有腹腔镜肝脏手术的适应证。现有的文献资料提示机器人肝肿瘤手术安全有效。对于适宜病例,机器人手术较开放手术创伤小、恢复快;与传统腹腔镜手术相比,机器人手术在近、远期疗效方面与之相当。机器人手术系统在微创大范围肝切除、后上段等困难部位肝切除、需重建血管及胆道的复杂肝切除术中有一定优势;但也存在手术费用高、手术时间长等局限。鉴于现阶段研究报道例数有限,尚需大样本前瞻性随机对照研究进一步评估其优缺点。

  9. 空间电荷限制电流法测量共混体系中空穴的迁移率%Measurement of the hole mobility in the blend system by space charge limited current

    Institute of Scientific and Technical Information of China (English)

    於黄忠

    2012-01-01

    The measurement of carrier mobility in organic semiconductor material and device is one of important study contents. The hole- only devices based on the different solvent blends of poly (3-hexylthiophene) (P3HT) and [6, 6]-phenyl C61-butyric acid methyl ester (PCBM) as acceptor are fabricated, the structures of the devices are all ITO/PEDOT:PSS/P3HT:PCBM/Au. The hole mobilities in the blend systems with different solvents and various annealing treatments are measured by the space charge limited current method. The results show that the J-V curves of charge transfer in the devices meet Mott-Gurney equation, the hole mobilities in the active layer with different solvents are different, the active layer formed with high boiling point solvent 1, 2-dichlorobenzene possesses higher hole mobility, heat treatment contributes to the improvement of the hole mobility in the devices. The reason of change of hole mobility is analyzed.%载流子迁移率测量是有机半导体材料与器件研究中的重要内容之一.以聚噻吩为电子给体材料,C60的衍生物为电子受体材料,制备了一种单电荷传输器件.用空间电荷限制电流法测出了不同溶剂形成的活性层及不同温度热处理后器件中空穴的迁移率.结果表明:器件中电荷的传输J-y曲线符合Mott-Gurney方程,不同溶剂形成活性层中空穴具有不同的迁移率,高沸点的溶剂1,2-二氯苯形成的活性层具有较高的空穴迁移率,热处理有利于器件中空穴迁移率的提高.同时还进一步分析了空穴迁移率变化的原因.

  10. Temperature profile and current meter data collected using current meter (PCM) from the CHAIN in the Northeast Atlantic Ocean (limit-40 W) as part of the International Decade of Ocean Exploration / Mid-Ocean Dynamics Experiment from 01 May 1973 to 01 June 1973 (NODC Accession 7600732)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, pressure, depth, east-west current component, and north-south current component data were collected using current meter (PCM) from the CHAIN in the...

  11. Limits on $\

    CERN Document Server

    Perego, D L

    2002-01-01

    A limit on the tau neutrino mass is obtained using all the $Z^{0} \\to \\tau^{+} \\tau^{-}$ data collected at LEP by the DELPHI detector between 1992 and 1995. In this analysis events in which one of the taus decays into one charged particle, while the second $\\tau$ decays into f{}ive charged pions (1-5 topology) have been used. The neutrino mass is determined from a bidimensional \\fit ~on the invariant mass $m^{*}_{5 \\pi}$ and on the energy $E_{5 \\pi}$ of the f{}ive $\\pi^{\\pm}$ system. The result found is $m_{\

  12. Quantum-limit spectroscopy

    CERN Document Server

    Ficek, Zbigniew

    2017-01-01

    This book covers the main ideas, methods, and recent developments of quantum-limit optical spectroscopy and applications to quantum information, resolution spectroscopy, measurements beyond quantum limits, measurement of decoherence, and entanglement. Quantum-limit spectroscopy lies at the frontier of current experimental and theoretical techniques, and is one of the areas of atomic spectroscopy where the quantization of the field is essential to predict and interpret the existing experimental results. Currently, there is an increasing interest in quantum and precision spectroscopy both theoretically and experimentally, due to significant progress in trapping and cooling of single atoms and ions. This progress allows one to explore in the most intimate detail the ways in which light interacts with atoms and to measure spectral properties and quantum effects with high precision. Moreover, it allows one to perform subtle tests of quantum mechanics on the single atom and single photon scale which were hardly eve...

  13. PLT rotating pumped limiter

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, S.A.; Budny, R.V.; Corso, V.; Boychuck, J.; Grisham, L.; Heifetz, D.; Hosea, J.; Luyber, S.; Loprest, P.; Manos, D.

    1984-07-01

    A limiter with a specially contoured front face and the ability to rotate during tokamak discharges has been installed in a PLT pump duct. These features have been selected to handle the unique particle removal and heat load requirements of ICRF heating and lower-hybrid current-drive experiments. The limiter has been conditioned and commissioned in an ion-beam test stand by irradiation with 1 MW power, 200 ms duration beams of 40 keV hydrogen ions. Operation in PLT during ohmic discharges has proven the ability of the limiter to reduce localized heating caused by energetic electron bombardment and to remove about 2% of the ions lost to the PLT walls and limiters.

  14. Age Limits.

    Science.gov (United States)

    Antfolk, Jan

    2017-03-01

    Whereas women of all ages prefer slightly older sexual partners, men-regardless of their age-have a preference for women in their 20s. Earlier research has suggested that this difference between the sexes' age preferences is resolved according to women's preferences. This research has not, however, sufficiently considered that the age range of considered partners might change over the life span. Here we investigated the age limits (youngest and oldest) of considered and actual sex partners in a population-based sample of 2,655 adults (aged 18-50 years). Over the investigated age span, women reported a narrower age range than men and women tended to prefer slightly older men. We also show that men's age range widens as they get older: While they continue to consider sex with young women, men also consider sex with women their own age or older. Contrary to earlier suggestions, men's sexual activity thus reflects also their own age range, although their potential interest in younger women is not likely converted into sexual activity. Compared to homosexual men, bisexual and heterosexual men were more unlikely to convert young preferences into actual behavior, supporting female-choice theory.

  15. Inrush Current Control Circuit

    Science.gov (United States)

    Cole, Steven W. (Inventor)

    2002-01-01

    An inrush current control circuit having an input terminal connected to a DC power supply and an output terminal connected to a load capacitor limits the inrush current that charges up the load capacitor during power up of a system. When the DC power supply applies a DC voltage to the input terminal, the inrush current control circuit produces a voltage ramp at the load capacitor instead of an abrupt DC voltage. The voltage ramp results in a constant low level current to charge up the load capacitor, greatly reducing the current drain on the DC power supply.

  16. Computed tomography evaluation with the use of automatic current modulator: possibilities and limitations; Avaliacao de imagens de tomografia computadorizada com o uso do modulador automatico de corrente: potencialidades e limitacoes

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Giordana Salvi de; Real, Jessica Villa; Froner, Ana Paula Pastre; Silva, Ana Maria Marques da, E-mail: giordana.souza@acad.pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil)

    2015-08-15

    The technology available in most modern equipment CT enables the automatic tube current modulation, according to the thickness variation of the anatomical region studied. This study aimed to evaluate the quantitative parameters related to the image quality produced by CT scanner, with and without the use of the manufacturer's dose modulation system. For this, Catphan 700 phantom was used, and images were acquired in a Philips scanner, with and without the use of current modulation, using a protocol adult skull. The results showed an increase of 20.8% of the CTDI{sub vol} and DLP with the use of the current modulator in relation to the images acquired with the same protocol without the modulator. It was observed that the image noise using the modulator had the lowest value, as well as higher spatial resolution due to the higher dose provided by the current modulation system. There were no significant differences in the uniformity and accuracy of CT number and even in linearity. Concluding, the dose optimization process using simulators should be carefully evaluated because it depends on the settings for each current modulation system assumed by the manufacturer. Although they supposedly seek the dose optimization, such systems can produce a considerable increase in dose, without significantly modifying the image quality for certain protocols. (author)

  17. Current direction, bathythermograph (xbt), CTD, and other data from moored current meter casts and other instruments in the Northwest Atlantic Ocean (limit-40 W) and North American Coastline-South as part of the North Carolina FRontal Eddy Dynamics Experiment (FRED) project, 1987-05-07 to 1987-11-01 (NCEI Accession 8900181)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current direction, bathythermograph (xbt), CTD, and other data were collected using moored current meter casts and other instruments in the Northwest Atlantic Ocean...

  18. Spin current

    CERN Document Server

    Valenzuela, Sergio O; Saitoh, Eiji; Kimura, Takashi

    2012-01-01

    In a new branch of physics and technology called spin-electronics or spintronics, the flow of electrical charge (usual current) as well as the flow of electron spin, the so-called 'spin current', are manipulated and controlled together. This book provides an introduction and guide to the new physics and application of spin current.

  19. Study of Electromagnetic Repulsion Switch to High Speed Reclosing and Recover Time Characteristics of Superconductor

    Science.gov (United States)

    Koyama, Tomonori; Kaiho, Katsuyuki; Yamaguchi, Iwao; Yanabu, Satoru

    Using a high-temperature superconductor, we constructed and tested a model superconducting fault current limiter (SFCL). The superconductor and vacuum interrupter as the commutation switch were connected in parallel using a bypass coil. When the fault current flows in this equipment, the superconductor is quenched and the current is then transferred to the parallel coil due to the voltage drop in the superconductor. This large current in the parallel coil actuates the magnetic repulsion mechanism of the vacuum interrupter and the current in the superconductor is broken. Using this equipment, the current flow time in the superconductor can be easily minimized. On the other hand, the fault current is also easily limited by large reactance of the parallel coil. This system has many merits. So, we introduced to electromagnetic repulsion switch. There is duty of high speed re-closing after interrupting fault current in the electrical power system. So the SFCL should be recovered to superconducting state before high speed re-closing. But, superconductor generated heat at the time of quench. It takes time to recover superconducting state. Therefore it is a matter of recovery time. In this paper, we studied recovery time of superconductor. Also, we proposed electromagnetic repulsion switch with reclosing system.

  20. Limits of proton conductivity.

    Science.gov (United States)

    Kreuer, Klaus-Dieter; Wohlfarth, Andreas

    2012-10-15

    Parasitic current seems to be the cause for the "highest proton conductivity" of a material reported to date. Kreuer and Wohlfarth verify this hypothesis by measuring the conductivity of the same materials after preparing them in a different way. They further explain the limits of proton conductivity and comment on the problems of determining the conductivity of small objects (e.g., whiskers, see picture).

  1. Incorporating protein transduction domains (PTD) within intracellular proteins associated with the 'stemness' phenotype. Novel use of such recombinant 'fusion' proteins to overcome current limitations of applying autologous adult stem cells in regenerative medicine?

    Science.gov (United States)

    Heng, Boon Chin; Cao, Tong

    2005-01-01

    Adult stem cells originating from post-natal tissues hold tremendous promise in regenerative medicine. Nevertheless, there are several deficiencies of adult stem cells that would limit their application in transplantation therapy, in particular their relative scarcity, restricted multi-potency and limited proliferative capacity in vitro. A possible approach to overcome these limitations would be to genetically modulate adult stem cells to strongly express genes that are closely associated with the 'stemness' phenotype. Overwhelming safety concerns would preclude the direct application of recombinant DNA technology in genetic modulation. Moreover, constitutive expression of 'stemness' genes would prevent adult stem cells from participating in tissue/organ regeneration upon transplantation. A novel alternative would be to incorporate protein transduction domains within intracellular proteins (i.e. transcription factors) that are associated with the 'stemness' phenotype. Such recombinant fusion proteins would then have the ability to translocate across the cell membrane and be internalized within the cytosol, thereby enabling them to exert a gene-modulatory effect on the cell, without any permanent genetic alteration. This would be particularly useful for maintaining the 'stemness' of adult stem cell populations during extensive ex vivo proliferation, to generate adequate cell numbers for transplantation therapy.

  2. Trends in poverty risks among people with and without limiting-longstanding illness by employment status in Sweden, Denmark, and the United Kingdom during the current economic recession -- a comparative study

    DEFF Research Database (Denmark)

    Falk, Johanna; Bruce, Daniel; Burström, Bo;

    2013-01-01

    Previous studies have found higher employment rates and lower risk of relative poverty among people with chronic illness in the Nordic countries than in the rest of Europe. However, Nordic countries have not been immune to the general rise in poverty in many welfare states in recent decades....... This study analysed the trends in poverty risks among a particularly vulnerable group in the labour market: people with limiting-longstanding illness (LLSI), examining the experience of those with and without employment, and compared to healthy people in employment in Sweden, Denmark and the United Kingdom....

  3. Analysis on Fault Current Limitation and Self-recovery of MMC Based on Clamp Double Sub-module%基于钳位双子模块的 MMC 故障清除和重启能力分析

    Institute of Scientific and Technical Information of China (English)

    丁云芝; 苏建徽; 周建

    2014-01-01

    针对当前已投入运行的高压直流(HVDC)输电工程中模块化多电平换流器(MMC)不具备直流侧故障电流闭锁能力的问题,分析了一种可自清除直流侧故障电流并且可重启动的 MMC 拓扑---基于钳位双子模块的 MMC。这种拓扑可在发生直流故障时通过闭锁所有绝缘栅双极型晶体管(IGBT)的触发信号和利用二极管的反向阻断能力迅速完成闭锁过程,从而达到无需交流断路器动作实现清除直流故障的目的。这种拓扑将半桥模块化 MMC 的调制方法和控制策略与可清除直流故障能力结合在一起,且具有结构简单、造价经济等特点。通过对半桥模块化 MMC 和钳位双子模块 MMC 在直流侧双极短路故障情况下的故障电流进行分析和仿真,验证了基于钳位双子模块的 MMC 在处理直流侧故障方面的能力和效果。%In view of the inability of the modular multilevel converter (MMC) in the high voltage direct current (HVDC) transmission projects in current operation to lock fault current on the DC side,an MMC topology based on clamp double sub-module(CDSM)capable of automatically eliminating and restarting the fault current on the DC side is analyzed.Because of the reverse blocking of diodes,blocking during a DC fault is achieved by blocking all the impulses of IGBTs,then the DC fault is eliminated without the action of AC breakers.Simple in structure and economical,this topology combines the modulation and the control strategy of MMC based on half bridge sub-module(HBSM-MMC)with the ability of recovering from a DC fault.A comparison with the HBSM-MMC in the case of a DC pole-to-pole fault by simulation and analysis has proved the performance of MMC based on CDSM in the control of DC fault current.

  4. 当前企业财务会计报告的局限性与改进措施%The Current Limitations and Development Trend of Enterprise Financial Accounting Reports

    Institute of Scientific and Technical Information of China (English)

    宣红石

    2016-01-01

    With the development of knowledge economy, enterprises are facing the market competition is increasingly fierce. As an important part of enterprise internal management, financial accounting work is constantly improving and innovation. In the new development environment, we must overcome the drawbacks and limitations of corporate financial reporting, and strengthen the management of financial reporting, standardize the standard of financial accounting work, improve the authenticity and effectiveness of the financial accounting report.%知识经济不断发展,企业所面临的市场竞争也日渐激烈。作为企业内部管理的重要内容,财务会计工作也在不断完善和创新。在新的发展环境下,必须克服企业财务报告中存在的弊端以及局限性,加强财务报告的管理力度,规范财务会计工作标准,提升财务会计报告的真实性、有效性。

  5. Transient analyses using symmetrical component calculus in three-phase resistive and transformer-type SFCLs

    Science.gov (United States)

    Cho, Y. S.; Choi, H. S.; Jung, B. I.

    2010-11-01

    A transformer-type superconducting fault current limiter (SFCL) can control fault current by adjusting a turn's ratio of the primary and secondary windings. In addition, by inserting a neutral line into the secondary winding, the power burden of the superconducting elements can be evenly distributed. We compared the operating and transient characteristics of the three-phase resistive and transformer-type SFCLs in the balanced and unbalanced faults that occur in power systems. In transformer-type SFCLs, where the primary and secondary windings of each phase were connected to one iron core, flux was induced to each winding of the normal phases by the fault current of the fault phase, thus causing simultaneous quench between superconducting elements. In the three-phase power systems, however, when faults occurred in more than two phases, the flux from fault current of the fault phase affected the other normal phase, thus decreasing the reduction ratio of fault current. We confirmed, however, that the fault current was reduced by 70% relative to cases without SFCLs. The results of the analysis of the transient characteristics of the three-phase transformer-type SFCL through the symmetrical component calculus showed that in the case of triple line-to-ground fault, a difference between positive and negative phase currents was large enough to cause an increase in the phase angle (δ) between the generator creating the power and the motor acting as a load. Thus, we expect that the transient stability deteriorates.

  6. Limitations Of Infrared Thermography

    Science.gov (United States)

    Schott, John R.

    1983-03-01

    The state of the art of quantitative infrared thermography is addressed. We are asking more and more of thermography in the field of energy conservation. An energy and dollar conscious public wants to know how much heat is being lost and how much money can be saved by retrofit. Many mission oriented approaches have been developed to address these questions. However, many fundamental questions about how thermography works and how far its capabilities can be pushed have not been addressed. In addition, the theoretical and practical limits of doing benefit cost studies with thermography have not been seriously addressed. This paper discusses the limitations of the current technology and describes many unanswered but important questions facing the future use of thermography for quantitative heat loss analysis.

  7. Current management of presbyopia

    Directory of Open Access Journals (Sweden)

    Pandelis A Papadopoulos

    2014-01-01

    Full Text Available Presbyopia is a physiologic inevitability that causes gradual loss of accommodation during the fifth decade of life. The correction of presbyopia and the restoration of accommodation are considered the final frontier of refractive surgery. Different approaches on the cornea, the crystalline lens and the sclera are being pursued to achieve surgical correction of this disability. There are however, a number of limitations and considerations that have prevented widespread acceptance of surgical correction for presbyopia. The quality of vision, optical and visual distortions, regression of effect, complications such as corneal ectasia and haze, anisometropia after monovision correction, impaired distance vision and the invasive nature of the currently techniques have limited the utilization of presbyopia surgery. The purpose of this paper is to provide an update of current procedures available for presbyopia correction and their limitations.

  8. Current Titles

    Energy Technology Data Exchange (ETDEWEB)

    Various

    2006-06-01

    This booklet is published for those interested in current research being conducted at the National Center for Electron Microscopy. The NCEM is a DOE-designated national user facility and is available at no charge to qualified researchers. Access is controlled by an external steering committee. Interested researchers may contact Jane Cavlina, Administrator, at 510/486-6036.

  9. 330 kV开关型零损耗故障限流装置的研制及人工短路试验%Development and Short-circuit Experiment of 330 kV Switch-type No-loss Fault Current Limiter

    Institute of Scientific and Technical Information of China (English)

    艾绍贵; 高峰; 黄永宁; 樊益平; 李延军; 王川

    2015-01-01

    Fault current Limiter is one of the efficient technological measures to solve the increasingly serious problem of excessive short-circuit current. A 330 kV switch-type no-loss fault current limiter based on intelligent fast switch technique and short-circuit current zero crossing point fast prediction and accurate phase control breaking technology is developed. Limiting short-circuit current of 80 kA and below to a safe breaking level within 20 ms is realized by the device based on modular design method, which realizes no-loss during normal operation and fault current limiting of any depth. The device is successfully used in the 330 kV line, and the safety, effectiveness and reliability of the device which has simple structure, low cost and small footprint are verified through field operation and two single-phase transient short-circuit experiment.%装设故障限流装置是解决日益严重电网短路电流超标问题的有效技术措施之一,利用智能快速开关技术、短路电流过零点快速预测及精确相控开断技术研制一套330 kV开关型零损耗电网故障限流装置。该装置采用模块化设计方法,使正常运行时损耗为零,且短路故障发生20 ms内,则可将80 kA及以下的短路电流限制在系统断路器的安全开断水平,从而实现任意深度的故障限流;装置成功用在330 kV线路上,通过带电、挂网运行和2次人工单相瞬时短路试验,验证装置满足安全性、有效性和可靠性的要求,同时结构简单合理,成本低廉且占地面积小。

  10. Research of Asynchronous Motor Torque Ramp Current Limiting Start Based on dsPIC30 F6014 A%基于dsPIC30 F6014 A的异步电机转矩斜坡限流起动研究∗

    Institute of Scientific and Technical Information of China (English)

    刘斌; 童军; 曹浩翔; 王侠辉

    2016-01-01

    The mathematical model of the T-type equivalent circuit of induction motor was analyzed and studied, the control method of the asynchronous motor torque ramp current limiting was proposed, the fuzzy PID adaptive control was used in the current limiting control section. On the basis of this theory, using the MATLAB/Simulink tool to construct the simulation platform, the soft start of the motor torque limiting control was carried out. The result showed that this method could improved the starting torque of the starting current of the motor, so the reliability of the theory of the limit flow of the torque and the slope was verified.%对异步电机的T型等效电路的数学模型进行分析与研究,提出了异步电机转矩斜坡限流起动的控制思路,并将模糊PID自适应控制思路运用在限流控制部分。在此理论基础下,利用MATLAB/Simulink工具构建仿真平台对电机转矩限流控制的软起动进行试验。试验结果说明,该方法在降低电机起动电流的同时还可以提高起动转矩,从而验证了转矩斜坡限流理论的可靠性。

  11. Current titles

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    This booklet is published for those interested in current research being conducted at the National Center for Electron Microscopy. The NCEM is a DOE-designated national user facility and is available at no charge to qualified researchers. Access is controlled by an external steering committee. Interested researchers may contact Gretchen Hermes at (510) 486-5006 or address below for a User`s Guide. Copies of available papers can be ordered from: Theda Crawford National Center for Electron Microscopy, Lawrence Berkeley Laboratory, One Cyclotron Rd., MS72, Berkeley, California, USA 94720.

  12. Beam-limiting and radiation-limiting interlocks

    Energy Technology Data Exchange (ETDEWEB)

    Macek, R.J.

    1996-04-01

    This paper reviews several aspects of beam-limiting and radiation- limiting interlocks used for personnel protection at high-intensity accelerators. It is based heavily on the experience at the Los Alamos Neutron Science Center (LANSCE) where instrumentation-based protection is used extensively. Topics include the need for ``active`` protection systems, system requirements, design criteria, and means of achieving and assessing acceptable reliability. The experience with several specific devices (ion chamber-based beam loss interlock, beam current limiter interlock, and neutron radiation interlock) designed and/or deployed to these requirements and criteria is evaluated.

  13. Current ornithology

    CERN Document Server

    1983-01-01

    The appearance of the first volume of a projected series is the occasion for comment on scope, aims, and genesis of the work. The scope of Current Ornithology is all of the biology of birds. Ornithology, as a whole-organism science, is concerned with birds at every level of bi­ ological organization, from the molecular to the community, at least from the Jurassic to the present time, and over every scholarly discipline in which bird biology is done; to say this is merely to expand a dic­ tionary definition of "ornithology. " The aim of the work, to be realized over several volumes, is to present reviews or position statements con­ cerning the active fields of ornithological research. The reviews will be relatively short, and often will be done from the viewpoint of a readily­ identified group or school. Such a work could have come into being at any time within the past fifty years, but that Current Ornithology appears now is a result of events that are only seven to eight years old. One important event wa...

  14. Long Wavelength Limit of the Current Convective Instability.

    Science.gov (United States)

    1984-02-23

    V " > v , velocity shear ( Satyanarayana and Ossakow...NR-5264 F/G 12/1 i ••>;y>vr>wv•>•’.’.•.’••,•.’.’•’•••’J." •’!ŕ *i-Wl’W.l 1 I’/1. *^^^^^^T^^^^^^^^ , I 1 ". m w\\ • I.I»J nn, i’ri L V i 12.8...025 MICROCOPY RESOLUTION TEST CHART NATIONAL »U«t AU Of STAMOANOS - ’MS • * &ä&ä^ .,.-. „•- .f .•- v ;•:•:•:•/•;•:•. ’ ^^^r^

  15. Beyond the current noise limit in imaging through turbulent medium

    CERN Document Server

    Popowicz, A; Pollo, A; Smolka, B

    2015-01-01

    Shift-and-add is an approach employed to mitigate the phenomenon of resolution degradation in images acquired through a turbulent medium. Using this technique, a large number of consecutive short exposures is registered below the coherence time of the atmosphere or other blurring medium. The acquired images are shifted to the position of the brightest speckle and stacked together to obtain high-resolution and high signal-to-noise frame. In this paper we present a highly efficient method for determination of frames shifts, even if in a single frame the object cannot be distinguished from the background noise. The technique utilizes our custom genetic algorithm, which iteratively evolves a set of image shifts. We used the maximal energy of stacked images as an objective function for shifts estimation and validate the efficiency of the method on simulated and real images of simple and complex sources. Obtained results confirmed, that our proposed method allows for the recovery of spatial distribution of objects ...

  16. Current limitation in low-voltage grids; Strombegrenzung fuer Niederspannungsnetze

    Energy Technology Data Exchange (ETDEWEB)

    Verstraate, F. [Schneider Electric GmbH, Ratingen (Germany)

    1997-12-31

    The electricity supply grids operated by public utilities, industrial enterprises etc. are faced with a further significant increase of their delivery capacity. In view of the high power density that is already available, this means a further increase of power plant capacities and additional meshing of network structures. (orig.) [Deutsch] Die elektrischen Netze von Industrie, EVUs usw. stehen in den naechsten Jahren vor einer weiteren erheblichen Steigerung ihrer Abgabeleistung. Bei der bereits vorhandenen hohen Leistungsdichte ergibt sich daraus die Notwendigkeit, sowohl die Kraftwerkskapazitaeten zu erhoehen als auch eine zusaetzliche Vermaschung der Netzstruktur vorzunehmen. (orig.)

  17. Parallel programming practical aspects, models and current limitations

    CERN Document Server

    Tarkov, Mikhail S

    2014-01-01

    Parallel programming is designed for the use of parallel computer systems for solving time-consuming problems that cannot be solved on a sequential computer in a reasonable time. These problems can be divided into two classes: 1. Processing large data arrays (including processing images and signals in real time)2. Simulation of complex physical processes and chemical reactions For each of these classes, prospective methods are designed for solving problems. For data processing, one of the most promising technologies is the use of artificial neural networks. Particles-in-cell method and cellular automata are very useful for simulation. Problems of scalability of parallel algorithms and the transfer of existing parallel programs to future parallel computers are very acute now. An important task is to optimize the use of the equipment (including the CPU cache) of parallel computers. Along with parallelizing information processing, it is essential to ensure the processing reliability by the relevant organization ...

  18. What limits the performance of current invasive Brain Machine Interfaces?

    Directory of Open Access Journals (Sweden)

    Gytis eBaranauskas

    2014-04-01

    Full Text Available The concept of a brain-machine interface (BMI or a computer-brain interface is simple: BMI creates a communication pathway for a direct control by brain of an external device. In reality BMIs are very complex devices and only recently the increase in computing power of microprocessors enabled a boom in BMI research that continues almost unabated to this date, the high point being the insertion of electrode arrays into the brains of 5 human patients in a clinical trial run by Cyberkinetics with few other clinical tests still in progress. Meanwhile several EEG-based BMI devices (non-invasive BMIs were launched commercially. Modern electronics and dry electrode technology made possible to drive the cost of some of these devices below few hundred dollars. However, the initial excitement of the direct control by brain waves of a computer or other equipment is dampened by large efforts required for learning, high error rates and slow response speed. All these problems are directly related to low information transfer rates typical for such EEG-based BMIs. In invasive BMIs employing multiple electrodes inserted into the brain one may expect much higher information transfer rates than in EEG-based BMIs because, in theory, each electrode provides an independent information channel. However, although invasive BMIs require more expensive equipment and have ethical problems related to the need to insert electrodes in the live brain, such financial and ethical costs are often not offset by a dramatic improvement in the information transfer rate. Thus the main topic of this review is why in invasive BMIs an apparently much larger information content obtained with multiple extracellular electrodes does not translate into much higher rates of information transfer? This paper explores possible answers to this question by concluding that more research on what movement parameters are encoded by neurons in motor cortex is needed before we can enjoy the next generation BMIs.

  19. Multivariate PAT solutions for biopharmaceutical cultivation: current progress and limitations

    NARCIS (Netherlands)

    Mercier, S.M.; Diepenbroek, B.; Wijffels, R.H.; Streefland, M.

    2014-01-01

    Increasingly elaborate and voluminous datasets are generated by the (bio)pharmaceutical industry and are a major challenge for application of PAT and QbD principles. Multivariate data analysis (MVDA) is required to delineate relevant process information from large multi-factorial and multi-collinear

  20. Genetic improvement of brewer's yeast: current state, perspectives and limits.

    Science.gov (United States)

    Saerens, Sofie M G; Duong, C Thuy; Nevoigt, Elke

    2010-05-01

    Brewer's yeast strain optimisation may lead to a more efficient beer production process, better final quality or healthier beer. However, brewer's yeast genetic improvement is very challenging, especially true when it comes to lager brewer's yeast (Saccharomyces pastorianus) which contributes to 90% of the total beer market. This yeast is a genetic hybrid and allopolyploid. While early studies applying traditional genetic approaches encountered many problems, the development of rational metabolic engineering strategies successfully introduced many desired properties into brewer's yeast. Recently, the first genome sequence of a lager brewer's strain became available. This has opened the door for applying advanced omics technologies and facilitating inverse metabolic engineering strategies. The latter approach takes advantage of natural diversity and aims at identifying and transferring the crucial genetic information for an interesting phenotype. In this way, strains can be optimised by introducing "natural" mutations. However, even when it comes to self-cloned strains, severe concerns about genetically modified organisms used in the food and beverage industry are still a major hurdle for any commercialisation. Therefore, research efforts will aim at developing new sophisticated screening methods for the isolation of natural mutants with the desired properties which are based on the knowledge of genotype-phenotype linkage.

  1. What limits the performance of current invasive brain machine interfaces?

    Science.gov (United States)

    Baranauskas, Gytis

    2014-01-01

    The concept of a brain-machine interface (BMI) or a computer-brain interface is simple: BMI creates a communication pathway for a direct control by brain of an external device. In reality BMIs are very complex devices and only recently the increase in computing power of microprocessors enabled a boom in BMI research that continues almost unabated to this date, the high point being the insertion of electrode arrays into the brains of 5 human patients in a clinical trial run by Cyberkinetics with few other clinical tests still in progress. Meanwhile several EEG-based BMI devices (non-invasive BMIs) were launched commercially. Modern electronics and dry electrode technology made possible to drive the cost of some of these devices below few hundred dollars. However, the initial excitement of the direct control by brain waves of a computer or other equipment is dampened by large efforts required for learning, high error rates and slow response speed. All these problems are directly related to low information transfer rates typical for such EEG-based BMIs. In invasive BMIs employing multiple electrodes inserted into the brain one may expect much higher information transfer rates than in EEG-based BMIs because, in theory, each electrode provides an independent information channel. However, although invasive BMIs require more expensive equipment and have ethical problems related to the need to insert electrodes in the live brain, such financial and ethical costs are often not offset by a dramatic improvement in the information transfer rate. Thus the main topic of this review is why in invasive BMIs an apparently much larger information content obtained with multiple extracellular electrodes does not translate into much higher rates of information transfer? This paper explores possible answers to this question by concluding that more research on what movement parameters are encoded by neurons in motor cortex is needed before we can enjoy the next generation BMIs.

  2. Determination of the Limiting Magnitude

    Science.gov (United States)

    Kingery, Aaron; Blaauw, Rhiannon

    2017-01-01

    The limiting magnitude of an optical camera system is an important property to understand since it is used to find the completeness limit of observations. Limiting magnitude depends on the hardware and software of the system, current weather conditions, and the angular speed of the objects observed. If an object exhibits a substantial angular rate during the exposure, its light spreads out over more pixels than the stationary stars. This spreading causes the limiting magnitude to be brighter when compared to the stellar limiting magnitude. The effect, which begins to become important when the object moves a full width at half max during a single exposure or video frame. For targets with high angular speeds or camera systems with narrow field of view or long exposures, this correction can be significant, up to several magnitudes. The stars in an image are often used to measure the limiting magnitude since they are stationary, have known brightness, and are present in large numbers, making the determination of the limiting magnitude fairly simple. In order to transform stellar limiting magnitude to object limiting magnitude, a correction must be applied accounting for the angular velocity. This technique is adopted in meteor and other fast-moving object observations, as the lack of a statistically significant sample of targets makes it virtually impossible to determine the limiting magnitude before the weather conditions change. While the weather is the dominant factor in observing satellites, the limiting magnitude for meteors also changes throughout the night due to the motion of a meteor shower or sporadic source radiant across the sky. This paper presents methods for determining the limiting stellar magnitude and the conversion to the target limiting magnitude.

  3. Economia solidária e reabilitação vocacional no campo da drogadição: possibilidades e limites das práticas atuais Cooperative work and vocational rehabilitation in the drug addiction treatment: opportunities and limitations of current practices

    Directory of Open Access Journals (Sweden)

    Alessandra Nagamine Bonadio

    2013-03-01

    perspectives. The literature on vocational rehabilitation was raised through a literature review on Medline, Pubmed and Lilacs, with the following key words: vocational rehabilitation, substance abuse treatment & work. The Brazilian Government guidelines were collected in the official publications available online by the Ministry of Health and Ministry of Labour and Employment of Brazil. The analysis of the material pointed out that the vocational rehabilitation practiced in North America and Europe focus on users of mental health services, proceeding to the work inclusion through the bias of the disease. The vocational rehabilitation emphasizes the replacement in the formal labor market, through programs aimed at skills training to get and keep a job. On the other hand, the Brazilian public policies are guided by the principles of cooperative and social economy. It privileges the human ethics in its entirety, as the subject and the purpose of higher economic activity, focusing on the strengths and resources of the work, rather than the limitations imposed by the disease or the socioeconomic status that has generated the situation of exclusion.

  4. 超导限流器短路实验的平台搭建及实验项目的实现%Construction of Short-Circuit Experiment Platform and Its Realization of Experiment Project for Superconducting Fault Current Limiter

    Institute of Scientific and Technical Information of China (English)

    王佳成; 姚磊; 梅军; 郑建勇; 于泳

    2013-01-01

    Introduction was made to the construction of short-circuit experiment platform for the superconducting fault current limiter and its work mode and principle. This paper gave the call process of the experimental data collected from the lower machine DSP to PC’s VB program. The short-circuit experiment of magnesium diboride superconducting fault current limiter was conducted under the conditions of liquid nitrogen. The experiment results show that the platform could correctly relfect the voltages at two sides of large current generator and the superconducting coil currents and effectively measure the temperature variation of the superconducting coil, to lay the foundation for the continuous experiment under the conditions of liquid nitrogen.%介绍了超导限流器短路实验平台的搭建过程及其工作方式与原理,并给出实验数据从下位机DSP采集到上位机VB程序调用的过程。进行了二硼化镁超导限流器在液氮条件下的短路实验,实验结果表明该平台能正确反映大电流发生器两侧电压以及超导线圈电流,并有效测量超导线圈的温度变化,为后续液氦条件下的实验打下了基础。

  5. HOME Income Limits

    Data.gov (United States)

    Department of Housing and Urban Development — HOME Income Limits are calculated using the same methodology that HUD uses for calculating the income limits for the Section 8 program. These limits are based on HUD...

  6. Passive immitance limiters

    OpenAIRE

    Filinyuk N. A.; Lischinskaya L. B.; Chekhmestruk R. Yu.

    2015-01-01

    The paper presents quadripole R, L, C immittance limiters, in which output immittance to the certain value depends on the input immittance. A classification of immittance limiters is given. Basic parameters are considered: low and high levels of output immittance limiters; low and high values of input immittance, corresponding to low and high levels of limitation, accordingly; range of possible values of output immittance; steepness of immittance limiters; time of wearing-out (or delay); high...

  7. Limits on {nu}{sub {mu}}({nu}{sub {mu}}){r_arrow}{nu}{sub {tau}}({nu}{sub {tau}}) and {nu}{sub {mu}}({nu}{sub {mu}}){r_arrow}({nu}{sub {ital e}}){nu}{sub {ital e}} oscillations from a precision measurement of neutrino-nucleon neutral current interactions

    Energy Technology Data Exchange (ETDEWEB)

    McFarland, K.S.; Naples, D.; Arroyo, C.G.; Auchincloss, P.; de Barbaro, P.; Bazarko, A.O.; Bernstein, R.H.; Bodek, A.; Bolton, T.; Budd, H.; Conrad, J.; Drucker, R.B.; Harris, D.A.; Johnson, R.A.; Kim, J.H.; King, B.J.; Kinnel, T.; Koizumi, G.; Koutsoliotas, S.; Lamm, M.J.; Lefmann, W.C.; Marsh, W.; McNulty, C.; Mishra, S.R.; Nienaber, P.; Nussbaum, M.; Oreglia, M.J.; Perera, L.; Quintas, P.Z.; Romosan, A.; Sakumoto, W.K.; Schumm, B.A.; Sciulli, F.J.; Seligman, W.G.; Shaevitz, M.H.; Smith, W.H.; Spentzouris, P.; Steiner, R.; Stern, E.G.; Vakili, M.; Yang, U.K. [Adelphi University, Garden City, New York 11530 (United States)]|[University of Chicago, Chicago, Illinois 60637 (United States)]|[University of Cincinnati, Cincinnati, Ohio 45221 (United States)]|[Columbia University, New York, New York 10027 (United States)]|[Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)]|[Kansas State University, Manhattan, Kansas 66506 (United States)]|[University of Oregon, Eugene, Oregon 97403 (United States)]|[University of Rochester, Rochester, New York 14627 (United States)]|[University of Wisconsin, Madison, Wisconsin 53706 (United States)]|[Xavier University, Cincinnati, Ohio 45207 (United States)

    1995-11-27

    We present limits on {nu}{sub {mu}}({nu}{sub {mu}}){r_arrow}{nu}{sub {tau}}({nu}{sub {tau}}) and {nu}{sub {mu}}({nu}{sub {mu}}){r_arrow}{nu}{sub {ital e}}({nu}{sub {ital e}}) oscillations based on a study of inclusive {nu}{ital N} interactions performed using the CCFR massive coarse-grained detector in the Fermilab Tevatron Quadrupole Triplet neutrino beam. The sensitivity to oscillations is from the difference in the longitudinal energy deposition pattern of {nu}{sub {mu}}{ital N} vs {nu}{sub {tau}}{ital N} or {nu}{sub {ital e}}{ital N} charged-current interactions. The {nu}{sub {mu}} energies ranged from 30 to 500 GeV with a mean of 140 GeV. The minimum and maximum {nu}{sub {mu}} flight lengths are 0.9 and 1.4 km, respectively. For {nu}{sub {mu}}{r_arrow}{nu}{sub {tau}} oscillations, the lowest 90% confidence upper limit in sin{sup 2}2{alpha} of 2.7{times}10{sup {minus}3} is obtained at {Delta}{ital m}{sup 2}{similar_to}50 eV{sup 2}. This result is the most stringent limit to date for 25{lt}{Delta}{ital m}{sup 2}{lt}90 eV{sup 2}. For {nu}{sub {mu}}{r_arrow}{nu}{sub {ital e}} oscillations, the lowest 90% confidence upper limit in sin{sup 2}2{alpha} of 1.9{times}10{sup {minus}3} is obtained at {Delta}{ital m}{sup 2}{similar_to}350 eV{sup 2}. This result is the most stringent limit to date for 250{lt}{Delta}{ital m}{sup 2}{lt}450 eV{sup 2}, and also excludes at 90% confidence much of the high {Delta}{ital m}{sup 2} region favored by the recent LSND observation. {copyright} {ital 1995} {ital The} {ital American} {ital Physical} {ital Society}.

  8. Problems of anthropogenic tritium limitation

    Directory of Open Access Journals (Sweden)

    Kochetkov О.A.

    2013-12-01

    Full Text Available This article contains the current situation in respect to the environmental concentrations of anthropogenic and natural tritium. There are presented and analyzed domestic standards for НТО of all Radiation Safety Standards (NRB, as well as the regulations analyzed for tritium in drinking water taken in other countries today. This article deals with the experience of limitation of tritium and focuses on the main problem of rationing of tritium — rationing of organically bound tritium.

  9. Multiobjective Optimization in Combinatorial Wind Farms System Integration and Resistive SFCL Using Analytical Hierarchy Process

    DEFF Research Database (Denmark)

    Moghadasi, Amirhasan; Sarwat, Arif; Guerrero, Josep M.

    2016-01-01

    on the extreme load reduction is effectively demonstrated. A large WPP has a complicated structure using several components, and the inclusion of RSFCL composes this layout more problematic for optimal performance of the system. Hence, the most-widely decision-making technique based on the analytic hierarchy...... process (AHP) is proposed for the optimal design of the combinatorial RSFCL and 50MW WPP to compute the three-dimensional alignment in Pareto front at the end of the optimization run. The numerical simulations verify effectiveness of the proposed approach, using the Pareto optimality concept....

  10. Derived limits for surface contamination

    CERN Document Server

    Wrixon, A D; Linsley, G S; White, D F

    1979-01-01

    Derived limits (DLs) for surface contamination were first established for use in the nuclear energy industry where a wide variety of radionuclides is encountered. They were later used in factories, hospitals, and universities, where the radionuclides used are normally fewer in number, either known or readily identifiable, and often of low toxicity. In these situations the current limits are frequently over-restrictive. This report describes a reassessment of the values in the light of more recent information on the possible pathways of exposure and the dose equivalent limits given in ICRP Publication 26. The reassessment is prompted also by the introduction of SI units. The results of the reassessment are used to produce a classification of DLs for all radionuclides for active and inactive area surfaces and for skin.

  11. VT Limited Access Highways

    Data.gov (United States)

    Vermont Center for Geographic Information — A limited-access road, known by various terms worldwide, including limited-access highway, dual carriageway, expressway, and partial controlled access highway, is a...

  12. Robust test limits

    NARCIS (Netherlands)

    Albers, Willem/Wim; Kallenberg, W.C.M.; Otten, G.D.

    1997-01-01

    Because of inaccuracies of the measurement process inspection of manufactured parts requires test limits which are more strict than the given specification limits. Test limits derived under the assumption of normality for product characteristics turn out to violate the prescribed bound on the

  13. Does decoherence in the thermodynamic limit exist?

    CERN Document Server

    Frasca, M

    2002-01-01

    We consider the Jaynes-Cummings model for N particles in the thermodynamic limit showing how it can produce decoherence on a Schr\\"odinger cat state. This mechanism can be observed in current experiments with cavities.

  14. The density limit in JET diverted plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, D.J.; Clement, S.; Gottardi, N.; Gowers, C.; Harbour, P.; Loarte, A.; Horton, L.; Lingertat, J.; Lowry, C.G.; Saibene, G.; Stamp, M.; Stork, D. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Monk, R. [Royal Holloway Coll., London (United Kingdom). Dept. of Physics

    1994-07-01

    In JET limiter plasmas the density limit is associated with radiated power fractions of 100% and, in plasmas with carbon limiters, it is invariably disruptive. However, in discharges with solid beryllium limiters the limit is identified with the formation of a MARFE and disruptions are less frequent. In addition, the improved conditioning of the vessel arising from the use of beryllium has significantly improved the density limit scaling, so that the maximum density rises with the square root of the input power. In diverted plasmas several confinement regimes exist, making the characterization of the density limit more complex. While the density limit in L-mode plasmas is generally disruptive, the limit in ELMy and ELM-free H-modes generally prompts a return to the L-mode and a disruption is not inevitable. The density limit does rise with the increasing power, but the L-to-H transition complicates the analysis. Nevertheless, at low plasma currents (<2 MA), densities significantly above the Greenwald limit can be achieved, while at higher currents power handling limitations have constrained the range of density which can be achieved. (authors). 7 refs., 4 figs.

  15. Passive immitance limiters

    Directory of Open Access Journals (Sweden)

    Filinyuk N. A.

    2015-06-01

    Full Text Available The paper presents quadripole R, L, C immittance limiters, in which output immittance to the certain value depends on the input immittance. A classification of immittance limiters is given. Basic parameters are considered: low and high levels of output immittance limiters; low and high values of input immittance, corresponding to low and high levels of limitation, accordingly; range of possible values of output immittance; steepness of immittance limiters; time of wearing-out (or delay; high and low cutoff frequencies; central working frequency; frequency band; relative range of working frequencies; non-linearity coefficient. The authors have designed passive R-, L-, C-limiters with possibility of limitation from above and from below. The influence of the input parasitic immittances on the immittance transfer characteristic is evaluated. In most cases parasite immittance does not influence the considered devices, including R-limiters «from above» with the input quality factor of QR(Linp=0,1…0,2 and L-limiters «from above» with high-quality input circuits with QL(Rinp>2. The analysis also shows that high-qualitiy circuits with QN(RinpN>3 should be used in C-limiters with input parasitic immittances, while at parasitic immittance of the limiting element low-quality circuits with QN(RiN>0,2 should be selected.

  16. Transungual drug delivery: current status.

    Science.gov (United States)

    Elkeeb, Rania; AliKhan, Ali; Elkeeb, Laila; Hui, Xiaoying; Maibach, Howard I

    2010-01-15

    Topical therapy is highly desirable in treating nail disorders due to its localized effects, which results in minimal adverse systemic events and possibly improved adherence. However, the effectiveness of topical therapies is limited by minimal drug permeability through the nail plate. Current research on nail permeation that focuses on altering the nail plate barrier by means of chemical treatments, penetration enhancers as well as physical and mechanical methods is reviewed. A new method of nail sampling is examined. Finally limitations of current ungual drug permeability studies are briefly discussed.

  17. 基于自收缩效应液态金属限流器中电弧行为特性的实验研究%Experimental Research of Arc Behaviour Characteristics in Liquid Metal Current Limiter Based on Self Pinch Effect

    Institute of Scientific and Technical Information of China (English)

    刘懿莹; 吴翊; 荣命哲; 何海龙; 李阳; 刘宏

    2012-01-01

    研究基于自收缩效应液态金属限流器(LMCL)中的电弧行为特性。设计了具有LMCL基本结构特征的实验模型。利用高速摄影技术获得的起弧和燃弧过程的影像以及通过数字示波器记录的电弧电压和电流波形,揭示了液态金属中电弧起弧机理,分析了电流对弧前自收缩过程的影响,研究了在单孔条件下电弧形态随电弧电压的演变规律。同时在实验过程中发现了电弧对电极的侵蚀现象,并通过分析其成因提出一种能够有效避免侵蚀的电极结构改进方法。该研究对进一步提高LMCL限流性能具指导意义。%The arc behavior characteristics in the liquid metal current limiter(LMCL) based on self pinch effect was investigated. An experimental setup which had basic structural characteristic of LMCL was designed. According to the images obtained the high speed photography and the waveform of arc voltage and current recorded by the oscilloscope, the nature of arc initiation in liquid metal is revealed, and the influence of current on the self pinch process of pre arcing is analyzed. The morphological changes of arc with the variation of arc voltage in one channel are studied. The phenomenon of arc erosion on the electrodes is observed during the experiment. An improved method of electrode structure, which can avoid the erosion effectively, is proposed.The research work is a significant guide to the improvement of LMCL current limiting charateristics.

  18. Current-Induced Membrane Discharge

    OpenAIRE

    Andersen, MB; Soestbergen, van, M Michiel; A Mani; Bruus, H.; Biesheuvel, PM; Bazant, MZ

    2012-01-01

    Possible mechanisms for overlimiting current (OLC) through aqueous ion-exchange membranes (exceeding diffusion limitation) have been debated for half a century. Flows consistent with electro-osmotic instability have recently been observed in microfluidic experiments, but the existing theory neglects chemical effects and remains to be quantitatively tested. Here, we show that charge regulation and water self-ionization can lead to OLC by “current-induced membrane discharge” (CIMD), even in the...

  19. 微电网不对称故障模式下IBDG运行特性及无畸变限流保护研究%Research on Operation Characteristics of IBDG under the Asymmetric Fault Mode of Micro-grid and Current Limiting Protection Distortionless

    Institute of Scientific and Technical Information of China (English)

    张蕊; 顾和荣

    2016-01-01

    微电网安全可靠的运行离不开精确地控制和保护。由于微电网中微电源自身的特点,使孤岛微电网中的电气量的变化在故障情况下与传统大电网有很大的差别。因此,研究不同故障情况下 IBDG 的运行特性以及它们对微电网系统故障特性的影响至关重要。本文研究了孤岛微电网不对称故障模式下 IBDG 的运行特性,对电气量的变化做出了定性分析。在不对称故障情况下针对传统的限流造成的电压电流畸变,采用无畸变限流方法,减少系统中的谐波分量。利用Matlab/Simulink 仿真软件搭建了由三台逆变器组成的微电网的仿真模型,设置故障参数并进行仿真研究,验证对微电网故障情况下IBDG的运行特性及无畸变限流理论分析的正确性。%Safe and reliable operation of microgrid cannot do without precise control and protection. Due to the characteristics of the microsources of microgrid, the changes of the electric parameters of isolated microgrid under fault condition have a big difference with the traditional power grid. So it is essential to study the operation characteristics of IBDG under different fault conditions and their influence on the fault characteristics of microgrid system. This paper studied the operation characteristics of IBDG under asymmetrical fault modes of isolated microgrid, and the variation of the electric quantity is analyzed qualitatively. In the case of asymmetric fault, the comparison and analysis are made for the different current limiting methods. The analysis shows that the method of distortion-free current limitation can greatly reduce the harmonic component in the system. On the basis of analyzing the operation characteristics of IBDG under the fault conditions of microgrid, the fault characteristics of microgrid are also analyzed simply. a simulation model of microgrid made up of three inverters is established by using Matlab/Simulink simulation

  20. Investigation of pulsed voltage limiters characteristics

    Directory of Open Access Journals (Sweden)

    Karimov A. V.

    2012-06-01

    Full Text Available A new method for measuring the voltage limit is offered. It has been designed to measure high-power pulsed current of voltage limiters. The error of this method is half as much as the error of the known method of direct measurement. The investigation of dependence of power capability of single-crystal and double-crystal voltage limiters and of the pulsed operation time on pulse duration.

  1. Investigation of Current Driven Loudspeakers

    DEFF Research Database (Denmark)

    Schneider, Henrik; Agerkvist, Finn T.; Knott, Arnold

    2015-01-01

    Current driven loudspeakers have previously been investigated but the literature is limited and the advantages and disadvantages are yet to be fully identified. This paper makes use of a non-linear loudspeaker model to analyse loudspeakers with distinct non-linear characteristics under voltage...... and current drive. A multi tone test signal is used in the evaluation of the driving schemes since it resembles audio signals to a higher degree than the signals used in total harmonic distortion and intermodulation distortion test methods. It is found that current drive is superior over voltage drive in a 5...

  2. Limitations to sharing entanglement

    CERN Document Server

    Kim, Jeong San; Sanders, Barry C

    2011-01-01

    We discuss limitations to sharing entanglement known as monogamy of entanglement. Our pedagogical approach commences with simple examples of limited entanglement sharing for pure three-qubit states and progresses to the more general case of mixed-state monogamy relations with multiple qudits.

  3. Limits to Inclusion

    Science.gov (United States)

    Hansen, Janne Hedegaard

    2012-01-01

    In this article, I will argue that a theoretical identification of the limit to inclusion is needed in the conceptual identification of inclusion. On the one hand, inclusion is formulated as a vision that is, in principle, limitless. On the other hand, there seems to be an agreement that inclusion has a limit in the pedagogical practice. However,…

  4. Limits to Inclusion

    Science.gov (United States)

    Hansen, Janne Hedegaard

    2012-01-01

    In this article, I will argue that a theoretical identification of the limit to inclusion is needed in the conceptual identification of inclusion. On the one hand, inclusion is formulated as a vision that is, in principle, limitless. On the other hand, there seems to be an agreement that inclusion has a limit in the pedagogical practice. However,…

  5. Numerical Limit Analysis:

    DEFF Research Database (Denmark)

    Damkilde, Lars

    2007-01-01

    Limit State analysis has a long history and many prominent researchers have contributed. The theoretical foundation is based on the upper- and lower-bound theorems which give a very comprehensive and elegant formulation on complicated physical problems. In the pre-computer age Limit State analysis...

  6. Numerical Limit Analysis:

    DEFF Research Database (Denmark)

    Damkilde, Lars

    2007-01-01

    Limit State analysis has a long history and many prominent researchers have contributed. The theoretical foundation is based on the upper- and lower-bound theorems which give a very comprehensive and elegant formulation on complicated physical problems. In the pre-computer age Limit State analysis...... also enabled engineers to solve practical problems within reinforced concrete, steel structures and geotechnics....

  7. The Hugoniot Elastic Limit Decay Limit

    Science.gov (United States)

    Billingsley, J. P.

    1997-07-01

    The Hugoniot Elastic Limit(HEL) precursor decay in shock loaded solids has been the subject of considerable experimental and theoretical investigation. Comparative evidence is presented to show that the elastic precursor wave particle velocity, UPHEL, for certain materials decays asymptotically with propagation distance to the DeBroglie velocity, V1, level. This is demonstrated for the following materials: iron, aluminum alloy 6061-T6, plexiglas(PMMA), nickel alloy(MAR-M200), and lithium flouride(LiF). The DeBroglie velocity, V1, equals h/2md, where h is Planck's Constant, m is the mass of one atom, and d is the closest distance between atoms. Thus a relationship has been established between a microscopically derived velocity, V1, and a macroscopically observed velocity, UPHEL.

  8. Nuclear Structure at the Limits

    Energy Technology Data Exchange (ETDEWEB)

    Nazarewicz, W.

    1998-01-12

    One of the frontiers of today�s nuclear science is the �journey to the limits� of atomic charge and nuclear mass, of neutron-to-proton ratio, and of angular momentum. The tour to the limits is not only a quest for new, exciting phenomena, but the new data are expected, as well, to bring qualitatively new information about the fundamental properties of the nucleonic many-body system, the nature of the nuclear interaction, and nucleonic correlations at various energy-distance scales. In this series of lectures, current developments in nuclear structure at the limits are discussed from a theoretical perspective, mainly concentrating on medium-mass and heavy nuclei.

  9. Circuit Controls Turn-On Current

    Science.gov (United States)

    Holmes, K. G.

    1972-01-01

    Single choke used in primary circuit with diode arrangement, maintaining dc current flow through choke and setting up a unidirectional magnetic field, limits turn-on current of transformer-rectifier power supply. Technique reduces number and weight of components and minimizes effect of initial inrush surge current on source.

  10. Current-induced membrane discharge

    CERN Document Server

    Andersen, M B; Mani, A; Bruus, H; Biesheuvel, P M; Bazant, M Z

    2012-01-01

    Possible mechanisms for over-limiting current (OLC) through aqueous ion-exchange membranes (exceeding diffusion limitation) have been debated for half a century. Flows consistent with electro-osmotic instability (EOI) have recently been observed in microfluidic experiments, but the existing theory neglects chemical effects and remains to be quantitatively tested. Here, we show that charge regulation and water self-ionization can lead to OLC by "current-induced membrane discharge" (CIMD), even in the absence of fluid flow. Salt depletion leads to a large electric field which expels water co-ions, causing the membrane to discharge and lose its selectivity. Since salt co-ions and water ions contribute to OLC, CIMD interferes with electrodialysis (salt counter-ion removal) but could be exploited for current-assisted ion exchange and pH control. CIMD also suppresses the extended space charge that leads to EOI, so it should be reconsidered in both models and experiments on OLC.

  11. Limited Attention and Discourse Structure

    CERN Document Server

    Walker, M A

    1995-01-01

    This squib examines the role of limited attention in a theory of discourse structure and proposes a model of attentional state that relates current hierarchical theories of discourse structure to empirical evidence about human discourse processing capabilities. First, I present examples that are not predicted by Grosz and Sidner's stack model of attentional state. Then I consider an alternative model of attentional state, the cache model, which accounts for the examples, and which makes particular processing predictions. Finally I suggest a number of ways that future research could distinguish the predictions of the cache model and the stack model.

  12. Modern Cosmology: Assumptions and Limits

    Science.gov (United States)

    Hwang, Jai-Chan

    2012-06-01

    Physical cosmology tries to understand the Universe at large with its origin and evolution. Observational and experimental situations in cosmology do not allow us to proceed purely based on the empirical means. We examine in which sense our cosmological assumptions in fact have shaped our current cosmological worldview with consequent inevitable limits. Cosmology, as other branches of science and knowledge, is a construct of human imagination reflecting the popular belief system of the era. The question at issue deserves further philosophic discussions. In Whitehead's words, ``philosophy, in one of its functions, is the critic of cosmologies.'' (Whitehead 1925).

  13. Modern Cosmology: Assumptions and Limits

    CERN Document Server

    Hwang, Jai-chan

    2012-01-01

    Physical cosmology tries to understand the Universe at large with its origin and evolution. Observational and experimental situations in cosmology do not allow us to proceed purely based on the empirical means. We examine in which sense our cosmological assumptions in fact have shaped our current cosmological worldview with consequent inevitable limits. Cosmology, as other branches of science and knowledge, is a construct of human imagination reflecting the popular belief system of the era. The question at issue deserves further philosophic discussions. In Whitehead's words, "philosophy, in one of its functions, is the critic of cosmologies". (Whitehead 1925)

  14. Swine brucellosis: current perspectives

    Directory of Open Access Journals (Sweden)

    Olsen SC

    2016-12-01

    Full Text Available SC Olsen, FM Tatum Infectious Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, USA Abstract: Brucella suis is a significant zoonotic species that is present in domestic livestock and wildlife in many countries worldwide. Transmission from animal reservoirs is the source of human infection as human-to-human transmission is very rare. Although swine brucellosis causes economic losses in domestic livestock, preventing human infection is the primary reason for its emphasis in disease control programs. Although disease prevalence varies worldwide, in areas outside of Europe, swine brucellosis is predominantly caused by B. suis biovars 1 and 3. In Europe, swine are predominantly infected with biovar 2 which is much less pathogenic in humans. In many areas worldwide, feral or wild populations of swine are important reservoir hosts. Like other Brucella spp. in their natural host, B. suis has developed mechanisms to survive in an intracellular environment and evade immune detection. Limitations in sensitivity and specificity of current diagnostics require use at a herd level, rather for individual animals. There is currently no commercial vaccine approved for preventing brucellosis in swine. Although not feasible in all situations, whole-herd depopulation is the most effective regulatory mechanism to control swine brucellosis. Keywords: livestock, transmission, pathogenicity, vaccine, host, infection

  15. ACA Federal Upper Limits

    Data.gov (United States)

    U.S. Department of Health & Human Services — Affordable Care Act Federal Upper Limits (FUL) based on the weighted average of the most recently reported monthly average manufacturer price (AMP) for...

  16. HUD Program Income Limits

    Data.gov (United States)

    Department of Housing and Urban Development — Income limits used to determine the income eligibility of applicants for assistance under three programs authorized by the National Housing Act. These programs are...

  17. Limit experiments of GARCH

    CERN Document Server

    Buchmann, Boris; 10.3150/10-BEJ328

    2012-01-01

    GARCH is one of the most prominent nonlinear time series models, both widely applied and thoroughly studied. Recently, it has been shown that the COGARCH model (which was introduced a few years ago by Kl\\"{u}ppelberg, Lindner and Maller) and Nelson's diffusion limit are the only functional continuous-time limits of GARCH in distribution. In contrast to Nelson's diffusion limit, COGARCH reproduces most of the stylized facts of financial time series. Since it has been proven that Nelson's diffusion is not asymptotically equivalent to GARCH in deficiency, in the present paper, we investigate the relation between GARCH and COGARCH in Le Cam's framework of statistical equivalence. We show that GARCH converges generically to COGARCH, even in deficiency, provided that the volatility processes are observed. Hence, from a theoretical point of view, COGARCH can indeed be considered as a continuous-time equivalent to GARCH. Otherwise, when the observations are incomplete, GARCH still has a limiting experiment, which we ...

  18. Limited Denial of Participation

    Data.gov (United States)

    Department of Housing and Urban Development — A Limited Denial of Participation (LDP) is an action taken by a HUD Field Office or the Deputy Assistant Secretary for Single Family (DASSF) or Multifamily (DASMF)...

  19. HOME Rent Limits

    Data.gov (United States)

    Department of Housing and Urban Development — In accordance with 24 CFR Part 92.252, HUD provides maximum HOME rent limits. The maximum HOME rents are the lesser of: The fair market rent for existing housing for...

  20. Limited Income and Resources

    Data.gov (United States)

    U.S. Department of Health & Human Services — Information for those with limited income and resources (those who may qualify for or already have the Low Income Subsidy to lower their prescription drug coverage...

  1. Limited Angle Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Kyung; Cho, Min Kook; Kim, Seong Sik [Pusan National University, Busan (Korea, Republic of)

    2007-07-01

    In computed tomography (CT), many situations are restricted to obtain enough number of projections or views to avoid artifacts such as streaking and geometrical distortion in the reconstructed images. Speed of motion of an object to be imaged can limit the number of views. Cardiovascular imaging is a representative example. Size of an object can also limit the complete traverse motion or geometrical complexity can obscure to be imaged at certain range of angles. These situations are frequently met in industrial nondestructive testing and evaluation. Dental CT also suffers from similar situation because cervical spine causes less x-ray penetration from some directions such that the available information is not sufficient for standard reconstruction algorithms. The limited angle tomography is now greatly paid attention as a new genre in medical and industrial imaging, popularly known as digital tomosynthesis. In this study, we introduce a modified filtered backprojection method in limited angle tomography and demonstrate its application for the dental imaging.

  2. SIS - Annual Catch Limit

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Annual Catch Limit (ACL) dataset within the Species Information System (SIS) contains information and data related to management reference points and catch data.

  3. Altruism and Reproductive Limitations

    Directory of Open Access Journals (Sweden)

    Carey J. Fitzgerald

    2009-04-01

    Full Text Available We examined how different types of reproductive limitations — functional (schizoid personality disorder and schizophrenia, physical (malnutrition, and sexual (bisexuality and homosexuality — influenced altruistic intentions toward hypothetical target individuals of differing degrees of relatedness (r = 0, .25, and .50. Participants were 312 undergraduate students who completed a questionnaire on altruism toward hypothetical friends, half-siblings, and siblings with these different types of reproductive limitations. Genetic relatedness and reproductive limitations did not influence altruistic decision-making when the cost of altruism was low but did as the cost of altruism increased, with participants being more likely to help a sibling over a half-sibling and a half-sibling over a friend. Participants also indicated they were more likely to help a healthy (control person over people with a reproductive limitation. Of the three types of reproductive limitations, functional limitations had the strongest effect on altruistic decision-making, indicating that people were less likely to help those who exhibit abnormal social behavior.

  4. Determination of the meteor limiting magnitude

    Science.gov (United States)

    Kingery, A.; Blaauw, R. C.

    2017-09-01

    We present our method to calculate the meteor limiting magnitude. The limiting meteor magnitude defines the faintest magnitude at which all meteors are still detected by a given system. An accurate measurement of the limiting magnitude is important in order to calculate the meteoroid flux from a meteor shower or sporadic source. Since meteor brightness is linked to meteor mass, the limiting magnitude is needed to calculate the limiting mass of the meteor flux measurement. The mass distribution of meteoroids is thought to follow a power law, thus being slightly off in the limiting magnitude can have a significant effect on the measured flux. Sky conditions can change on fairly short timescales; therefore one must monitor the meteor limiting magnitude at regular intervals throughout the night, rather than just measuring it once. We use the stellar limiting magnitude as a proxy of the meteor limiting magnitude. Our method for determining the stellar limiting magnitude and how we transform it into the meteor limiting magnitude is presented. These methods are currently applied to NASA's wide-field meteor camera network to determine nightly fluxes, but are applicable to other camera networks.

  5. Fundamental Limits of Cooperation

    CERN Document Server

    Lozano, Angel; Andrews, Jeffrey G

    2012-01-01

    Cooperation is viewed as a key ingredient for interference management in wireless systems. This paper shows that cooperation has fundamental limitations. The main result is that even full cooperation between transmitters cannot in general change an interference-limited network to a noise-limited network. The key idea is that there exists a spectral efficiency upper bound that is independent of the transmit power. First, a spectral efficiency upper bound is established for systems that rely on pilot-assisted channel estimation; in this framework, cooperation is shown to be possible only within clusters of limited size, which are subject to out-of-cluster interference whose power scales with that of the in-cluster signals. Second, an upper bound is also shown to exist when cooperation is through noncoherent communication; thus, the spectral efficiency limitation is not a by-product of the reliance on pilot-assisted channel estimation. Consequently, existing literature that routinely assumes the high-power spect...

  6. The quantum geometric limit

    CERN Document Server

    Lloyd, Seth

    2012-01-01

    This letter analyzes the limits that quantum mechanics imposes on the accuracy to which spacetime geometry can be measured. By applying the fundamental physical bounds to measurement accuracy to ensembles of clocks and signals moving in curved spacetime -- e.g., the global positioning system -- I derive a covariant version of the quantum geometric limit: the total number of ticks of clocks and clicks of detectors that can be contained in a four volume of spacetime of radius r and temporal extent t is less than or equal to rt/\\pi x_P t_P, where x_P, t_P are the Planck length and time. The quantum geometric limit bounds the number of events or `ops' that can take place in a four-volume of spacetime: each event is associated with a Planck-scale area. Conversely, I show that if each quantum event is associated with such an area, then Einstein's equations must hold. The quantum geometric limit is consistent with and complementary to the holographic bound which limits the number of bits that can exist within a spat...

  7. Scaling Limits of Graphene Nanoelectrodes.

    Science.gov (United States)

    Sarwat, Syed Ghazi; Gehring, Pascal; Rodriguez Hernandez, Gerardo; Warner, Jamie H; Briggs, G Andrew D; Mol, Jan A; Bhaskaran, Harish

    2017-06-14

    Graphene nanogap electrodes have been of recent interest in a variety of fields, ranging from molecular electronics to phase change memories. Several recent reports have highlighted that scaling graphene nanogaps to even smaller sizes is a promising route to more efficient and robust molecular and memory devices. Despite the significant interest, the operating and scaling limits of these electrodes are completely unknown. In this paper, we report on our observations of consistent voltage driven resistance switching in sub-5 nm graphene nanogaps. We find that such electrical switching from an insulating state to a conductive state occurs at very low currents and voltages (0.06 μA and 140 mV), independent of the conditions (room ambient, low temperatures, as well as in vacuum), thus portending potential limits to scaling of functional devices with carbon electrodes. We then associate this phenomenon to the formation and rupture of carbon chains. Using a phase change material in the nanogap as a demonstrator device, fabricated using a self-alignment technique, we show that for gap sizes approaching 1 nm the switching is dominated by such carbon chain formation, creating a fundamental scaling limit for potential devices. These findings have important implications, not only for fundamental science, but also in terms of potential applications.

  8. FANCM limits meiotic crossovers.

    Science.gov (United States)

    Crismani, Wayne; Girard, Chloé; Froger, Nicole; Pradillo, Mónica; Santos, Juan Luis; Chelysheva, Liudmila; Copenhaver, Gregory P; Horlow, Christine; Mercier, Raphaël

    2012-06-22

    The number of meiotic crossovers (COs) is tightly regulated within a narrow range, despite a large excess of molecular precursors. The factors that limit COs remain largely unknown. Here, using a genetic screen in Arabidopsis thaliana, we identified the highly conserved FANCM helicase, which is required for genome stability in humans and yeasts, as a major factor limiting meiotic CO formation. The fancm mutant has a threefold-increased CO frequency as compared to the wild type. These extra COs arise not from the pathway that accounts for most of the COs in wild type, but from an alternate, normally minor pathway. Thus, FANCM is a key factor imposing an upper limit on the number of meiotic COs, and its manipulation holds much promise for plant breeding.

  9. Quantum-Limited Spectroscopy

    CERN Document Server

    Truong, Gar-Wing; May, Eric F; Stace, Thomas M; Luiten, Andre N

    2015-01-01

    Spectroscopy has an illustrious history delivering serendipitous discoveries and providing a stringent testbed for new physical predictions, including applications from trace materials detection, to understanding the atmospheres of stars and planets, and even constraining cosmological models. Reaching fundamental-noise limits permits optimal extraction of spectroscopic information from an absorption measurement. Here we demonstrate a quantum-limited spectrometer that delivers high-precision measurements of the absorption lineshape. These measurements yield a ten-fold improvement in the accuracy of the excited-state (6P$_{1/2}$) hyperfine splitting in Cs, and reveals a breakdown in the well-known Voigt spectral profile. We develop a theoretical model that accounts for this breakdown, explaining the observations to within the shot-noise limit. Our model enables us to infer the thermal velocity-dispersion of the Cs vapour with an uncertainty of 35ppm within an hour. This allows us to determine a value for Boltzm...

  10. Overlimiting current in a microchannel

    CERN Document Server

    Dydek, E Victoria; Rubinstein, Isaak; Deng, D S; Mani, Ali; Bazant, Martin Z

    2011-01-01

    We revisit the classical problem of diffusion-limited ion transport to a membrane (or electrode) by considering the effects of charged side walls. Using simple mathematical models and numerical simulations, we identify three basic mechanisms for over-limiting current in a microchannel: (i) {\\it surface conduction} carried by excess counterions, which dominates for very thin channels, (ii) convection by {\\it electro-osmotic flow} on the side walls, which dominates for thicker channels and transitions to (iii) {\\it electro-osmotic instability} on the membrane end in very thick channels. These intriguing electrokinetic phenomena may find applications in biological separations, water desalination, and electrochemical energy storage.

  11. Limits of Lubrication in

    DEFF Research Database (Denmark)

    Olsson, David Dam

    by strategic surfaces in comparison to normal stainless steel surfaces implying a larger extent of bi-axial stretching. Numerical simulations have been applied in order to evaluate limits of lubrication in the simulative strip reduction based on predictions of critical parameters appearing in terms...... of temperature and contact pressure. The numerical models have been calibrated regarding friction and thermal contact resistance based on experimental results from actual testing conditions. It has been found that predictions of limits of lubrication are possible by numerical means and that the FE...

  12. Current therapies for premature ejaculation.

    Science.gov (United States)

    Gur, Serap; Kadowitz, Philip J; Sikka, Suresh C

    2016-07-01

    Premature ejaculation (PE) subjectively affects 20-30% of men globally. Until recently, understanding of PE was hampered by the absence of a widely accepted definition, paucity of evidence-based clinical studies, and the absence of an appropriate animal model. Here, we elaborate on the current definition of PE, its pathogenesis, currently available therapies, and future treatment prospects. Most treatments for PE are 'off-label' and include selective serotonin reuptake inhibitors (SSRIs), topical anesthetics, tramadol, and phosphodiesterase type 5 (PDE5) inhibitors. Such knowledge of the benefit and limitations of each treatment will help to direct future drug design and formulations.

  13. Extreme geomagnetically induced currents

    Science.gov (United States)

    Kataoka, Ryuho; Ngwira, Chigomezyo

    2016-12-01

    We propose an emergency alert framework for geomagnetically induced currents (GICs), based on the empirically extreme values and theoretical upper limits of the solar wind parameters and of d B/d t, the time derivative of magnetic field variations at ground. We expect this framework to be useful for preparing against extreme events. Our analysis is based on a review of various papers, including those presented during Extreme Space Weather Workshops held in Japan in 2011, 2012, 2013, and 2014. Large-amplitude d B/d t values are the major cause of hazards associated with three different types of GICs: (1) slow d B/d t with ring current evolution (RC-type), (2) fast d B/d t associated with auroral electrojet activity (AE-type), and (3) transient d B/d t of sudden commencements (SC-type). We set "caution," "warning," and "emergency" alert levels during the main phase of superstorms with the peak Dst index of less than -300 nT (once per 10 years), -600 nT (once per 60 years), or -900 nT (once per 100 years), respectively. The extreme d B/d t values of the AE-type GICs are 2000, 4000, and 6000 nT/min at caution, warning, and emergency levels, respectively. For the SC-type GICs, a "transient alert" is also proposed for d B/d t values of 40 nT/s at low latitudes and 110 nT/s at high latitudes, especially when the solar energetic particle flux is unusually high.

  14. Limits to global groundwater consumption

    Science.gov (United States)

    de Graaf, I.; Van Beek, L. P.; Sutanudjaja, E.; Wada, Y.; Bierkens, M. F.

    2016-12-01

    Groundwater is the largest accessible freshwater resource worldwide and is of critical importance for irrigation, and so for global food security. For many regions of the world where groundwater abstraction exceeds groundwater recharge, persistent groundwater depletion occurs. A direct consequence of depletion is falling groundwater levels, reducing baseflows to rivers, harming ecosystems. Also, pumping costs increase, wells dry up and land subsidence can occur. Water demands are expected to increase further due to growing population, economic development and climate change, posing the urgent question how sustainable current water abstractions are worldwide and where and when these abstractions approach conceivable limits with all the associated problems. Here, we estimated past and future trends (1960-2050) in groundwater levels resulting from changes in abstractions and climate and predicted when limits of groundwater consumption are reached. We explored these limits by predicting where and when groundwater levels drop that low that groundwater becomes unattainable for abstractions and how river flows are affected. Water availabilities, abstractions, and lateral groundwater flows are simulated (5 arcmin. resolution) using a coupled version of the global hydrological model PCR-GLOBWB and a groundwater model based on MODFLOW. The groundwater model includes a parameterization of the worlds confined and unconfined aquifer systems, needed for a realistic simulation of groundwater head dynamics. Results show that, next to the existing regions experiencing groundwater depletion (like India, Pakistan, Central Valley) new regions will develop, e.g. Southern Europe, the Middle East, and Africa. Using a limit that reflects present-day feasibility of groundwater abstraction, we estimate that in 2050 groundwater becomes unattainable for 20% of the global population, mainly in the developing countries and pumping cost will increase significantly. Largest impacts are found

  15. Limits to responsible innovation

    NARCIS (Netherlands)

    de Hoop, E.; Pols, Auke; Romijn, Henny

    2016-01-01

    Responsible Innovation (RI) is a young field of research that has nevertheless had remarkable successes in dissemination within academic and political circles. However, there is relatively little awareness of its limits, blind spots and situations in which it cannot be used for actual innovation tra

  16. The Limits of Laughter.

    Science.gov (United States)

    Mindess, Harvey

    1983-01-01

    Three incidents which elucidate the limits of laughter are described. Most persons enjoy humor as comic relief, but when humor strikes a blow at something they hold dear, they find it very hard to laugh. People are upset by an irreverent attitude toward things they hold in esteem. (RM)

  17. Pushing the Photon Limit

    NARCIS (Netherlands)

    Wientjes, Emilie; Renger, Jan; Cogdell, Richard; Hulst, van Niek F.

    2016-01-01

    Nanoantennas are well-known for their effective role in fluorescence enhancement, both in excitation and emission. Enhancements of 3-4 orders of magnitude have been reported. Yet in practice, the photon emission is limited by saturation due to the time that a molecule spends in singlet and especi

  18. Tightening Home Purchase Limits

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    More Chinese cities will limit home purchase to cool the red-hot real estate market In June 2011,the average house price in 100 Chinese cities was 8,856 yuan ($1,373)per square meter.Of these cities,house prices in 75 of them increased

  19. Limitation of Auditors' Liability

    DEFF Research Database (Denmark)

    Werlauff, Erik; Foged-Ladefoged, Lise Kolding

    2014-01-01

    The article examines the question of whether rules on the limitation of auditors’ liability within the perspective of EU law are needed, and if so, which rules can provide an appropriate balance between the potential injured party’s interests and those of the auditing sector, including with respect...

  20. Limits of Software Reuse

    NARCIS (Netherlands)

    Holenderski, L.

    2006-01-01

    Software reuse is considered one of the main techniques to increasesoftware productivity. We present two simple mathematical argumentsthat show some theoretical limits of reuse. It turns out that the increase of productivity due to internal reuse is at most linear, farfrom the needed exponential gr

  1. Current measurement apparatus

    Science.gov (United States)

    Umans, Stephen D.

    2008-11-11

    Apparatus and methods are provided for a system for measurement of a current in a conductor such that the conductor current may be momentarily directed to a current measurement element in order to maintain proper current without significantly increasing an amount of power dissipation attributable to the current measurement element or adding resistance to assist in current measurement. The apparatus and methods described herein are useful in superconducting circuits where it is necessary to monitor current carried by the superconducting elements while minimizing the effects of power dissipation attributable to the current measurement element.

  2. Superconducting Current Leads for Cryogenic Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Space flight cryocoolers will be able to handle limited heat loads at their expected operating temperatures and the current leads may be the dominant contributor to...

  3. Umbilical metastases: current viewpoint

    Directory of Open Access Journals (Sweden)

    Egidi Federico

    2005-02-01

    Full Text Available Abstract Background Umbilical metastases from a malignant neoplasm, also termed Sister Mary Joseph's nodule, are not commonly reported in the English literature, and they have usually been considered as a sign of a poor prognosis for the patient. The present article reports on the current view point on umbilical metastasis besides discussing the epidemiology, clinical presentation, pathophysiology and treatment. Method A search of Pubmed was carried out using the term 'umblic*' and 'metastases' or metastasis' revealed no references. Another search was made using the term "Sister Joseph's nodule" or sister Joseph nodule" that revealed 99 references. Of these there were 14 review articles, however when the search was limited to English language it yielded only 20 articles. Articles selected from these form the basis of this report along with cross references. Results The primary lesions usually arise from gastrointestinal or genitourinary tract malignancies and may be the presenting symptom or sign of a primary tumour in an unknown site. Conclusion A careful evaluation of all umbilical lesions, including an early biopsy if appropriate, is recommended. Recent studies suggest an aggressive surgical approach combined with chemotherapy for such patients may improve survival.

  4. Current trends in minilaparoscopy.

    Science.gov (United States)

    Small Layne, Alyssa; Pinkard, Lauren; Shepherd, Jessica

    2016-08-01

    The purpose of this review is to understand the current use of minilaparoscopy in the field and how minilaparoscopy compares with traditional laparoscopy in terms of operative times, complications, pain, and cosmesis. Although there are few randomized controlled trials comparing minilaparoscopy with traditional laparoscopy in gynecologic procedures, the results suggest that minilaparoscopy can be performed safely with improved cosmetic outcomes and similar complication rates and operating times. Postoperative pain may be decreased with minimizing incisions sizes. Recently, case reports and case series have been published demonstrating the use of minilaparoscopy across many subtypes of gynecologic surgery. Traditional laparoscopic surgery has become common practice in gynecology as it has been found to be a well tolerated procedure with improved outcomes and decreased morbidity when compared with laparotomy. Although minilaparoscopy has been used for over 2 decades, its role in gynecology is continuing to evolve. Minilaparoscopy is a growing surgical option in gynecology as we try to minimize the impact of surgery. Results of minilaparoscopy in gynecology mirror those found in urology and general surgery. Although research is limited, minilaparoscopy has proven to be a well tolerated alternative for gynecology.

  5. Age Limit of Pediatrics.

    Science.gov (United States)

    Hardin, Amy Peykoff; Hackell, Jesse M

    2017-09-01

    Pediatrics is a multifaceted specialty that encompasses children's physical, psychosocial, developmental, and mental health. Pediatric care may begin periconceptionally and continues through gestation, infancy, childhood, adolescence, and young adulthood. Although adolescence and young adulthood are recognizable phases of life, an upper age limit is not easily demarcated and varies depending on the individual patient. The establishment of arbitrary age limits on pediatric care by health care providers should be discouraged. The decision to continue care with a pediatrician or pediatric medical or surgical subspecialist should be made solely by the patient (and family, when appropriate) and the physician and must take into account the physical and psychosocial needs of the patient and the abilities of the pediatric provider to meet these needs. Copyright © 2017 by the American Academy of Pediatrics.

  6. Telescopic limiting magnitudes

    Science.gov (United States)

    Schaefer, Bradley E.

    1990-01-01

    The prediction of the magnitude of the faintest star visible through a telescope by a visual observer is a difficult problem in physiology. Many prediction formulas have been advanced over the years, but most do not even consider the magnification used. Here, the prediction algorithm problem is attacked with two complimentary approaches: (1) First, a theoretical algorithm was developed based on physiological data for the sensitivity of the eye. This algorithm also accounts for the transmission of the atmosphere and the telescope, the brightness of the sky, the color of the star, the age of the observer, the aperture, and the magnification. (2) Second, 314 observed values for the limiting magnitude were collected as a test of the formula. It is found that the formula does accurately predict the average observed limiting magnitudes under all conditions.

  7. Limiting Temperatures in Multifragmentation

    CERN Document Server

    Trautmann, W

    2008-01-01

    The systematic data set on isotopic effects in spectator fragmentation collected recently at the GSI laboratory permits the investigation of the N/Z dependence of the nuclear caloric curve which is of interest in several respects. In particular, new light is shed on the proposed interpretation of chemical breakup temperatures as a manifestation of the limiting temperatures predicted by the Hartree-Fock model. The obtained results are discussed within the general context of temperature measurements in multifragmentation reactions.

  8. Limits of Nuclear Stability

    CERN Document Server

    Nerlo-Pomorska, B; Kleban, M

    2003-01-01

    The modern version of the liquid-drop model (LSD) is compared with the macroscopic part of the binding energy evaluated within the Hartree-Fock- Bogoliubov procedure with the Gogny force and the relativistic mean field theory. The parameters of a liquid-drop like mass formula which approximate on the average the self-consistent results are compared with other models. The limits of nuclear stability predicted by these models are discussed.

  9. Extreme Physics and Informational/Computational Limits

    Energy Technology Data Exchange (ETDEWEB)

    Di Sia, Paolo, E-mail: paolo.disia@univr.it, E-mail: 10alla33@virgilio.it [Department of Computer Science, Faculty of Science, Verona University, Strada Le Grazie 15, I-37134 Verona (Italy) and Faculty of Computer Science, Free University of Bozen, Piazza Domenicani 3, I-39100 Bozen-Bolzano (Italy)

    2011-07-08

    A sector of the current theoretical physics, even called 'extreme physics', deals with topics concerning superstring theories, multiverse, quantum teleportation, negative energy, and more, that only few years ago were considered scientific imaginations or purely speculative physics. Present experimental lines of evidence and implications of cosmological observations seem on the contrary support such theories. These new physical developments lead to informational limits, as the quantity of information, that a physical system can record, and computational limits, resulting from considerations regarding black holes and space-time fluctuations. In this paper I consider important limits for information and computation resulting in particular from string theories and its foundations.

  10. Elastic limit of silicane.

    Science.gov (United States)

    Peng, Qing; De, Suvranu

    2014-10-21

    Silicane is a fully hydrogenated silicene-a counterpart of graphene-having promising applications in hydrogen storage with capacities larger than 6 wt%. Knowledge of its elastic limit is critical in its applications as well as tailoring its electronic properties by strain. Here we investigate the mechanical response of silicane to various strains using first-principles calculations based on density functional theory. We illustrate that non-linear elastic behavior is prominent in two-dimensional nanomaterials as opposed to bulk materials. The elastic limits defined by ultimate tensile strains are 0.22, 0.28, and 0.25 along armchair, zigzag, and biaxial directions, respectively, an increase of 29%, 33%, and 24% respectively in reference to silicene. The in-plane stiffness and Poisson ratio are reduced by a factor of 16% and 26%, respectively. However, hydrogenation/dehydrogenation has little effect on its ultimate tensile strengths. We obtained high order elastic constants for a rigorous continuum description of the nonlinear elastic response. The limitation of second, third, fourth, and fifth order elastic constants are in the strain range of 0.02, 0.08, and 0.13, and 0.21, respectively. The pressure effect on the second order elastic constants and Poisson's ratio were predicted from the third order elastic constants. Our results could provide a safe guide for promising applications and strain-engineering the functions and properties of silicane monolayers.

  11. Cryogenic current leads

    Energy Technology Data Exchange (ETDEWEB)

    Zizek, F.

    1982-01-01

    Theoretical, technical and design questions are examined of cryogenic current leads for SP of magnetic systems. Simplified mathematical models are presented for the current leads. To illustrate modeling, the calculation is made of the real current leads for 500 A and three variants of current leads for 1500 A for the enterprise ''Shkoda.''

  12. Morphology and Microtopology of Cation-Exchange Polymers and the Origin of the Overlimiting Current

    NARCIS (Netherlands)

    Balster, J.H.; Yildirim, M.H.; Stamatialis, Dimitrios; Ibanez, R.; Lammertink, Rob G.H.; Jordan, V.; Wessling, Matthias

    2007-01-01

    In electrodialysis desalination processes, the operating current density is limited by concentration polarization. In contrast to other membrane processes such as ultrafiltration, in electrodialysis, current transport above the limiting current is possible. In this work, the origin of the

  13. Current interruption transients calculation

    CERN Document Server

    Peelo, David F

    2014-01-01

    Provides an original, detailed and practical description of current interruption transients, origins, and the circuits involved, and how they can be calculated Current Interruption Transients Calculationis a comprehensive resource for the understanding, calculation and analysis of the transient recovery voltages (TRVs) and related re-ignition or re-striking transients associated with fault current interruption and the switching of inductive and capacitive load currents in circuits. This book provides an original, detailed and practical description of current interruption transients, origins,

  14. Photon and graviton mass limits

    Energy Technology Data Exchange (ETDEWEB)

    Nieto, Michael [Los Alamos National Laboratory; Goldhaber Scharff, Alfred [SUNY

    2008-01-01

    We review past and current studies of possible long-distance, low-frequency deviations from Maxwell electrodynamics and Einstein gravity. Both have passed through three phases: (1) Testing the inverse-square laws of Newton and Coulomb, (2) Seeking a nonzero value for the rest mass of photon or graviton, and (3) Considering more degrees of freedom, allowing mass while preserving gauge or general-coordinate invariance. For electrodynamics there continues to be no sign of any deviation. Since our previous review the lower limit on the photon Compton wavelength (associated with weakening of electromagnetic fields in vacuum over large distance scale) has improved by four orders of magnitude, to about one astronomical unit. Rapid current progress in astronomical observations makes it likely that there will be further advances. These ultimately could yield a bound exceeding galactic dimensions, as has long been contemplated. Meanwhile, for gravity there have been strong arguments about even the concept of a graviton rest mass. At the same time there are striking observations, commonly labeled 'dark matter' and 'dark energy' that some argue imply modified gravity. This makes the questions for gravity much more interesting. For dark matter, which involves increased attraction at large distances, any explanation by modified gravity would be qualitatively different from graviton mass. Because dark energy is associated with reduced attraction at large distances, it might be explained by a graviton-mass-like effect.

  15. Limits to growth reconsidered.

    Science.gov (United States)

    Hagen, E E

    1972-01-01

    In their book, ''The Limits of Growth,'' the authors conclude that through pollution, exhaustion of natural resources, and limits to the food supply, the world faces a catastrophic fall in population and in living standards by the middle of the 21st century. The authors fail to state, however, 1 centrally important assumption underlying their results, but which is present through their omission of the contrary assumption. In their model the continuing technical progress that has been a primary feature of the material world for the past 200 years suddenly ceases. The assumptions of the model presented in ''Limits of Growth'' are not the assumptions other analysts make - these are strangely unrealistic. These assumptions require closer examination. The assumption concerning population assumes that the sole determinants of birthrates are the level of industrialization and the food supply. This is not good demography, for demographers have long recognized that it may have been the decrease in death rates, not industrialization or the rise in income, that caused the decrease in birthrates. Furthermore, their theory that many of the natural resources are irreplacable is like the belief that the sun revolves around the earth. It is obvious and false. It neglects that part of technical process which includes invention of new natural resources. Technical advance is needed and the following are some of the problems that technical advance must overcome: 1) a need to discover how to increase food production progressively while preventing the runoff of chemical fertilizers from the soil into waterways, 2) the ''natural'' minerals on which until recently all have depended are ''biodegradable,'' 3) there is a similar problem with radioactive nuclear wastes; 4) energy must dissipate into heat; and 5) there is a need to hasten the decline in birthrates throughout the world. In conclusion, indefinitely continuing growth is not regarded as desirable only as possible.

  16. Orind Refractories Limited

    Institute of Scientific and Technical Information of China (English)

    Mr R. Mishra; Group Manging Director

    2005-01-01

    @@ "Sight can be acquired, Vision cannot". Orind Refractories Limited (ORIND), China was formed with this rare vision. At a time when the world was testing the tepid waters of China; Mr. Ravin Jhunjhunwala, Chairman of ORIND and the management of ORIND India had looked over the Great Wall to begin a journey of success. Incorported on 18th August 1994 with an initial investment of USD 5 million, ORL caters to the ever-demanding needs of the steel industry and beyond. Incidentally ORIND was the first wholly owned India company to set up base in China. Pesently, ORIND China has a 616 strong work force including 23 expatriates.

  17. Drinking to the Limit

    DEFF Research Database (Denmark)

    Järvinen, Margaretha; Ellersgaard, Christoph Houman; Larsen, Anton Grau

    2014-01-01

    The aim of this article is to analyse social status differences in alcohol norms and practices seen from the perspective of ‘health governance’. Survey data on 1442 employees in a middle-sized, Danish firm are used to construct a Bourdieu-inspired social space, tied to four forms of capital: econ...... by the Danish National Health Board. Rather, this article identifies a relatively large group of high-positioned respondents balancing at the limits of risky drinking – or transgressing them, if measured by international standards....

  18. Limitations in forensic odontology

    Directory of Open Access Journals (Sweden)

    B Kavitha

    2009-01-01

    Full Text Available The concept of using dental evidence in forensic investigation has kindled so much interest in the recent past that forensic odontology is even suggested as the single positive identification method to solve certain forensic cases. In this process, the shortcomings in forensic odontology though few are overlooked. These discrepancies associated with various methods are to be weighed cautiously to make forensic odontology a more accurate, reliable, and reproducible investigatory science. In this paper, we present our understanding of the limitations in various methods employed in forensic odontology.

  19. Marketing with limited budget

    OpenAIRE

    Smirnova, Daria

    2017-01-01

    The purpose of this research-based thesis was to get an idea how managers of two small resembling hotels of a specific region deal with marketing process with a limited budget. In addition, the aim of the thesis was to examine if hotel managers who were interviewed perceive marketing only in the way of ‘promotion’ rather than marketing research, marketing mix and marketing environment theories. It was also found out if hotel managers of those hotels consider marketing as a key to successful h...

  20. Radiation from charges in the continuum limit

    CERN Document Server

    Ianconescu, Reuven

    2012-01-01

    It is known that an accelerating charge radiates according to Larmor formula. On the other hand, any DC current following a curvilinear path, e.g. a circular loop, consists of accelerating charges, but in such case the radiated power is 0. The scope of this paper is to analyze and quantify how the radiation vanishes when one goes to the continuum DC limit.

  1. Limits to biofuels

    Directory of Open Access Journals (Sweden)

    Johansson S.

    2013-06-01

    Full Text Available Biofuel production is dependent upon agriculture and forestry systems, and the expectations of future biofuel potential are high. A study of the global food production and biofuel production from edible crops implies that biofuel produced from edible parts of crops lead to a global deficit of food. This is rather well known, which is why there is a strong urge to develop biofuel systems that make use of residues or products from forest to eliminate competition with food production. However, biofuel from agro-residues still depend upon the crop production system, and there are many parameters to deal with in order to investigate the sustainability of biofuel production. There is a theoretical limit to how much biofuel can be achieved globally from agro-residues and this amounts to approximately one third of todays’ use of fossil fuels in the transport sector. In reality this theoretical potential may be eliminated by the energy use in the biomass-conversion technologies and production systems, depending on what type of assessment method is used. By surveying existing studies on biofuel conversion the theoretical limit of biofuels from 2010 years’ agricultural production was found to be either non-existent due to energy consumption in the conversion process, or up to 2–6000TWh (biogas from residues and waste and ethanol from woody biomass in the more optimistic cases.

  2. Smoothness of limit functors

    Indian Academy of Sciences (India)

    Benedictus Margaux

    2015-05-01

    Let be a scheme. Assume that we are given an action of the one dimensional split torus $\\mathbb{G}_{m,S}$ on a smooth affine -scheme $\\mathfrak{X}$. We consider the limit (also called attractor) subfunctor $\\mathfrak{X}_{}$ consisting of points whose orbit under the given action `admits a limit at 0’. We show that $\\mathfrak{X}_{}$ is representable by a smooth closed subscheme of $\\mathfrak{X}$. This result generalizes a theorem of Conrad et al. (Pseudo-reductive groups (2010) Cambridge Univ. Press) where the case when $\\mathfrak{X}$ is an affine smooth group and $\\mathbb{G}_{m,S}$ acts as a group automorphisms of $\\mathfrak{X}$ is considered. It also occurs as a special case of a recent result by Drinfeld on the action of $\\mathbb{G}_{m,S}$ on algebraic spaces (Proposition 1.4.20 of Drinfeld V, On algebraic spaces with an action of $\\mathfrak{G}_{m}$, preprint 2013) in case is of finite type over a field.

  3. Limitations of inclusive fitness.

    Science.gov (United States)

    Allen, Benjamin; Nowak, Martin A; Wilson, Edward O

    2013-12-10

    Until recently, inclusive fitness has been widely accepted as a general method to explain the evolution of social behavior. Affirming and expanding earlier criticism, we demonstrate that inclusive fitness is instead a limited concept, which exists only for a small subset of evolutionary processes. Inclusive fitness assumes that personal fitness is the sum of additive components caused by individual actions. This assumption does not hold for the majority of evolutionary processes or scenarios. To sidestep this limitation, inclusive fitness theorists have proposed a method using linear regression. On the basis of this method, it is claimed that inclusive fitness theory (i) predicts the direction of allele frequency changes, (ii) reveals the reasons for these changes, (iii) is as general as natural selection, and (iv) provides a universal design principle for evolution. In this paper we evaluate these claims, and show that all of them are unfounded. If the objective is to analyze whether mutations that modify social behavior are favored or opposed by natural selection, then no aspect of inclusive fitness theory is needed.

  4. (Limiting the greenhouse effect)

    Energy Technology Data Exchange (ETDEWEB)

    Rayner, S.

    1991-01-07

    Traveler attended the Dahlem Research Conference organized by the Freien Universitat, Berlin. The subject of the conference was Limiting the Greenhouse Effect: Options for Controlling Atmospheric CO{sub 2} Accumulation. Like all Dahlem workshops, this was a meeting of scientific experts, although the disciplines represented were broader than usual, ranging across anthropology, economics, international relations, forestry, engineering, and atmospheric chemistry. Participation by scientists from developing countries was limited. The conference was divided into four multidisciplinary working groups. Traveler acted as moderator for Group 3 which examined the question What knowledge is required to tackle the principal social and institutional barriers to reducing CO{sub 2} emissions'' The working rapporteur was Jesse Ausubel of Rockefeller University. Other working groups examined the economic costs, benefits, and technical feasibility of options to reduce emissions per unit of energy service; the options for reducing energy use per unit of GNP; and the significant of linkage between strategies to reduce CO{sub 2} emissions and other goals. Draft reports of the working groups are appended. Overall, the conference identified a number of important research needs in all four areas. It may prove particularly important in bringing the social and institutional research needs relevant to climate change closer to the forefront of the scientific and policy communities than hitherto.

  5. Whole-body staging of malignant melanoma. Advantages, limitations and current importance of PET-CT, whole-body MRI and PET-MRI; Ganzkoerperdiagnostik beim malignen Melanom. Vorteile, Grenzen und aktueller Stellenwert von PET-CT, GK-MRT und PET-MRT

    Energy Technology Data Exchange (ETDEWEB)

    Pfannenberg, C.; Schwenzer, N. [Eberhard-Karls-Universitaet Tuebingen, Abteilung Diagnostische und Interventionelle Radiologie, Tuebingen (Germany)

    2015-01-16

    Cross-sectional imaging methods are currently the standard methods for staging of advanced melanoma. The former time-consuming and expensive multimodality approach is increasingly being replaced by novel whole-body (WB) staging methods, such as 18F-fluorodeoxyglucose positron emission tomography/computed tomography ({sup 18}F-FDG-PET-CT) and whole-body magnetic resonance imaging (WBMRI) because they offer a complete head-to-toe coverage of the patient in a single examination with an accurate and sensitive detection of tumor spread. Several studies in patients with advanced melanoma revealed that PET-CT is more sensitive and specific than conventional modalities, such as CT alone resulting in a change of management in up to 30 % of cases. Due to the limited sensitivity of PET for lesions smaller than 1 cm, PET-CT is not useful for the initial work-up of patients with stage I and II melanoma but has proven to be superior for detection of distant metastases, which is essential prior to surgical metastasectomy. If PET-CT is not available WB-CT or WB-MRI can alternatively be used and WB-MRI including diffusion-weighted imaging (DWI) has become a real alternative for staging of melanoma patients. So far, however, only few reports suffering from small numbers of cases and heterogeneous design have compared the diagnostic performance of WB-MRI and PET-CT. The preliminary results indicate a high overall diagnostic accuracy of both methods; however, these methods differ in organ-based detection rates: PET-CT was more accurate in N-staging and detection of lung and soft tissue metastases whereas WB-MRI was superior in detecting liver, bone and brain metastases. The value of PET-MRI for staging of advanced melanoma is the subject of ongoing clinical studies. (orig.) [German] Schnittbildmethoden sind heute der Standard bei der Ausbreitungsdiagnostik ab Stadium III des malignen Melanoms. Das fruehere zeit- und kostenaufwendige multimodale Konzept wird heute durch Ganzkoerper

  6. Fahr's disease: current perspectives

    Directory of Open Access Journals (Sweden)

    Tai XY

    2015-07-01

    Full Text Available Xin You Tai, Amit BatlaUCL Institute of Neurology, Queen Square, London, UKAbstract: Based on original descriptions of brain calcification by Theodor Fahr, brain calcification, and more specifically basal ganglia calcification, is referred to as Fahr's syndrome. Recent identification of genetic mutations has concerted the description of this erstwhile heterogeneous condition which we refer to here as Fahr's disease. Fahr's disease refers to idiopathic calcification of the basal ganglia without a secondary (non-genetic cause. Idiopathic basal ganglia calcification (IBGC is another term, which offers a more accurate description of this condition. Within the last 2 years, genetic mutations for IBGC have been described in SLC20A2, PDGFB, and PDGFRB. These findings broaden our understanding of the pathophysiology and encourage a search for specific treatment options in this rare but disabling condition. Clinically, parkinsonism, dystonia, and other movement disorders are the most common clinical features, but psychiatric features can predominate. Cases with confirmed genetic mutations reveal new clinical features linked with Fahr's disease, such as headaches. Computed tomography or magnetic resonance imaging is usually the trigger for suspecting Fahr's disease and important for identifying the calcification pattern. Symmetric calcification of the globus pallidus, thalamus, and dentate nucleus is the most common pattern in IBGC, but other parts of the brain such as the cerebellum are involved. Treatment of Fahr's disease is currently limited and is largely symptomatic. A better understanding of this condition in light of genetic findings is important to improve the clinical diagnosis and develop specific treatment options.Keywords: Fahr's disease, basal ganglia calcification, parkinsonism, calcium

  7. Limits of Executive Control

    Science.gov (United States)

    Verbruggen, Frederick; McAndrew, Amy; Weidemann, Gabrielle; Stevens, Tobias; McLaren, Ian P. L.

    2016-01-01

    Cognitive-control theories attribute action control to executive processes that modulate behavior on the basis of expectancy or task rules. In the current study, we examined corticospinal excitability and behavioral performance in a go/no-go task. Go and no-go trials were presented in runs of five, and go and no-go runs alternated predictably. At the beginning of each trial, subjects indicated whether they expected a go trial or a no-go trial. Analyses revealed that subjects immediately adjusted their expectancy ratings when a new run started. However, motor excitability was primarily associated with the properties of the previous trial, rather than the predicted properties of the current trial. We also observed a large latency cost at the beginning of a go run (i.e., reaction times were longer for the first trial in a go run than for the second trial). These findings indicate that actions in predictable environments are substantially influenced by previous events, even if this influence conflicts with conscious expectancies about upcoming events. PMID:27000177

  8. Occupational exposure limits and olfaction in hyperbaric environments

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, M.E. [MATSU, Harwell (United Kingdom)

    1999-05-01

    This report with 62 references presents the results of a literature review of current information on exposure limits and olfaction in hyperbaric environments. Sources of contamination in the hyperbaric environment are identified, and measured concentrations of contaminants, occupational limits for contaminants in hyperbaric conditions, and principles adopted for the establishment of exposure limits are examined. Toxicological studies and olfaction and sense of smell are discussed, Details of current practice, alternative strategies, monitoring techniques, and the data on olfaction are given.

  9. Currents for Arbitrary Helicity

    CERN Document Server

    Dragon, Norbert

    2016-01-01

    Using Mackey's classification of unitary representations of the Poincar\\'e group on massles states of arbitrary helicity we disprove the claim that states with helicity |h|>=1 cannot couple to a conserved current by constructing such a current.

  10. Magnetic current sensor

    Science.gov (United States)

    Black, Jr., William C. (Inventor); Hermann, Theodore M. (Inventor)

    1998-01-01

    A current determiner having an output at which representations of input currents are provided having an input conductor for the input current and a current sensor supported on a substrate electrically isolated from one another but with the sensor positioned in the magnetic fields arising about the input conductor due to any input currents. The sensor extends along the substrate in a direction primarily perpendicular to the extent of the input conductor and is formed of at least a pair of thin-film ferromagnetic layers separated by a non-magnetic conductive layer. The sensor can be electrically connected to a electronic circuitry formed in the substrate including a nonlinearity adaptation circuit to provide representations of the input currents of increased accuracy despite nonlinearities in the current sensor, and can include further current sensors in bridge circuits.

  11. Array Antenna Limitations

    CERN Document Server

    Jonsson, B L G; Hussain, N

    2013-01-01

    This letter defines a physical bound based array figure of merit that provides a tool to compare the performance of both single and multi-band array antennas with respect to return-loss, thickness of the array over the ground-plane, and scan-range. The result is based on a sum-rule result of Rozanov-type for linear polarization. For single-band antennas it extends an existing limit for a given fixed scan-angle to include the whole scan-range of the array, as well as the unit-cell structure in the bound. The letter ends with an investigation of the array figure of merit for some wideband and/or wide-scan antennas with linear polarization. We find arrays with a figure of merit >0.6 that empirically defines high-performance antennas with respect to this measure.

  12. Personal Freedom beyond Limits

    Directory of Open Access Journals (Sweden)

    Juan Fernando Sellés

    2013-07-01

    Full Text Available In this work we distinguish between freedom in the human manifestations (intelligence, will,actions and personal freedom in the personal intimacy. This second is beyond the freedom reached bythe classic and modern thought, since it takes root in the personnel act of being. Because of it, it is not possible to characterize this freedom like the classic description as ‘domain over the own acts’, becauseit is a description of ‘categorial’ order; neither like present day ‘autonomy’ or ‘independence’, becausethe existence of one person alone is impossible, since ‘person’ means relation, personal free openingto other persons, description of the ‘transcendental’ order and, therefore, to the margin of limits.

  13. Universal Limit on Communication

    CERN Document Server

    Bousso, Raphael

    2016-01-01

    I derive a universal upper bound on the capacity of any communication channel between two distant systems. The Holevo quantity, and hence the mutual information, is at most of order $E \\Delta t / \\hbar$, where $E$ the average energy of the signal, and $\\Delta t$ is the amount of time for which detectors operate. The bound does not depend on the size or mass of the emitting and receiving systems, nor on the nature of the signal. No restrictions on preparing and processing the signal are imposed. As an example, I consider the encoding of information in the transverse or angular position of a signal emitted and received by systems of arbitrarily large cross-section. In the limit of a large message space, quantum effects become important even if individual signals are classical, and the bound is upheld.

  14. Clinical limitations of Invisalign.

    Science.gov (United States)

    Phan, Xiem; Ling, Paul H

    2007-04-01

    Adult patients seeking orthodontic treatment are increasingly motivated by esthetic considerations. The majority of these patients reject wearing labial fixed appliances and are looking instead to more esthetic treatment options, including lingual orthodontics and Invisalign appliances. Since Align Technology introduced the Invisalign appliance in 1999 in an extensive public campaign, the appliance has gained tremendous attention from adult patients and dental professionals. The transparency of the Invisalign appliance enhances its esthetic appeal for those adult patients who are averse to wearing conventional labial fixed orthodontic appliances. Although guidelines about the types of malocclusions that this technique can treat exist, few clinical studies have assessed the effectiveness of the appliance. A few recent studies have outlined some of the limitations associated with this technique that clinicians should recognize early before choosing treatment options.

  15. The Limits to Relevance

    Science.gov (United States)

    Averill, M.; Briggle, A.

    2006-12-01

    Science policy and knowledge production lately have taken a pragmatic turn. Funding agencies increasingly are requiring scientists to explain the relevance of their work to society. This stems in part from mounting critiques of the "linear model" of knowledge production in which scientists operating according to their own interests or disciplinary standards are presumed to automatically produce knowledge that is of relevance outside of their narrow communities. Many contend that funded scientific research should be linked more directly to societal goals, which implies a shift in the kind of research that will be funded. While both authors support the concept of useful science, we question the exact meaning of "relevance" and the wisdom of allowing it to control research agendas. We hope to contribute to the conversation by thinking more critically about the meaning and limits of the term "relevance" and the trade-offs implicit in a narrow utilitarian approach. The paper will consider which interests tend to be privileged by an emphasis on relevance and address issues such as whose goals ought to be pursued and why, and who gets to decide. We will consider how relevance, narrowly construed, may actually limit the ultimate utility of scientific research. The paper also will reflect on the worthiness of research goals themselves and their relationship to a broader view of what it means to be human and to live in society. Just as there is more to being human than the pragmatic demands of daily life, there is more at issue with knowledge production than finding the most efficient ways to satisfy consumer preferences or fix near-term policy problems. We will conclude by calling for a balanced approach to funding research that addresses society's most pressing needs but also supports innovative research with less immediately apparent application.

  16. Current and Current Fluctuations in Quantum Shuttles

    DEFF Research Database (Denmark)

    Jauho, Antti-Pekka; Flindt, Christian; Novotny, Tomas

    2005-01-01

    theoretical tools needed for the analysis, e.g., generalized master equations and Wigner functions, and we outline the methods how the resulting large numerical problems can be handled. Illustrative results are given for current, noise, and full counting statistics for a number of model systems. Throughout...

  17. Controlled current inductors

    Science.gov (United States)

    Thaler, S.

    1970-01-01

    Magnetic permeability and shape of special core inserts are varied to produce desired changes in saturation characteristics of current dependent inductor, thus improving its inductance-to-current properties. Materials and saturation levels of the core pieces are selected to permit a wide variety of relationships between inductance and current.

  18. BOOK REVIEW: The Current Comparator

    Science.gov (United States)

    Petersons, Oskars

    1989-01-01

    techniques for magnetic errors and magnetic-shield excitation for capacitive errors. The magnetic-shield-excitation technique leads naturally to two-stage transformer approaches, described in a small subchapter. Sensitivity of current comparators is discussed in terms of available signal levels for given excitations and current-comparator characteristics. The discussion, however, does not cover more basic limitations, such as inherent noise. A subchapter is devoted to electronically-aided current transformers. Although electronically-aided transformers are not in a strict sense current comparators, many of the design considerations and error sources are the same. Seven different circuits are presented with a brief qualitative discussion. The third chapter, covering design and construction, will be exceptionally valuable for someone needing basic information on how to construct a current comparator quickly. Indeed, all the necessary design, construction, and testing steps are presented in a well-illustrated 15-page chapter. The tests for shielding effectiveness discussed in this chapter and the knowledge of interwinding capacitances calculable from the equations in the previous chapter should enable one also to predict the limits of errors without an exhaustive and complete calibration. Chapter 4 is devoted to current-transformer calibration—the original objective for the current-comparator development work. The principal tool for this is the compensated current comparator, in effect a two-stage transformer operated in the current-comparator mode. The compensated current comparator is not only accurate but is also an extremely versatile device and, hence, deserves the attention that it receives in this book. Considerable space is devoted to the calibration of current comparators themselves using other current comparators in ratio-buildup (bootstrap) techniques. This information is more than most of the users will want since the pre-eminent feature of a current comparator is

  19. Decomposition of residue currents

    OpenAIRE

    Andersson, Mats; Wulcan, Elizabeth

    2007-01-01

    Given a submodule $J\\subset \\mathcal O_0^{\\oplus r}$ and a free resolution of $J$ one can define a certain vector valued residue current whose annihilator is $J$. We make a decomposition of the current with respect to Ass$(J)$ that correspond to a primary decomposition of $J$. As a tool we introduce a class of currents that includes usual residue and principal value currents; in particular these currents admit a certain type of restriction to analytic varieties and more generally to construct...

  20. Circle Points Discharge Tube Current Controller

    Institute of Scientific and Technical Information of China (English)

    Meng Jinjia; Meng Lisheng

    2005-01-01

    Circle points discharge tube current controller is a new type device to limit theoutput of high voltage discharge current. Circle points uniform corona discharge to form airionization current in the discharge tube. On the outside, even if the discharge electrode is sparkdischarging or the two discharge electrodes are short circuited, the air ionization current in the tuberemains within a stable range, and there is no spark discharge. In this case, when the dischargecurrent only increases slightly, the requirement to limited current is obtained. By installing thecontroller at a discharge pole with a small power but high voltage supply, we can realize the shiftbetween the continuous spark line discharge and corona discharge. This provides a new simpledevice for spark discharge research and is a supplement to the Townsend discharge experiment.