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Sample records for ac metal-enclosed switchgear

  1. Metal-enclosed, air-insulated traction switchgear - developments and applications

    Energy Technology Data Exchange (ETDEWEB)

    Loenard, D.; Northe, J. [Balfour Beatty Rail GmbH Power Systems, Offenbach (Germany)

    2006-07-01

    TracFeed {sup registered} TA switchgear series has been extended and successfully type tested under exceptional conditions for the requirements of 15 kV 16,7 Hz traction power supply systems. Therefore, air-insulated, metal-enclosed prefabricated switchgear systems are available for AC power supply with 15 kV 16,7 Hz in one- and two-pole configurations. The new switchgears are now in use in several installations. (orig.)

  2. High-voltage switchgear and controlgear part 200 : AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV

    CERN Document Server

    International Electrotechnical Commission. Geneva

    2011-01-01

    Specifies requirements for factory-assembled metal-enclosed switchgear and controlgear for alternating current of rated voltages above 1 kV and up to and including 52 kV for indoor and outdoor installation, and for service frequencies up to and including 60 Hz. Enclosures may include fixed and removable components and may be filled with fluid (liquid or gas) to provide insulation. This standard defines several types of metal enclosed switchgear and controlgear which differ due to - the consequences on network service continuity in case of maintenance on the switchgear and controlgear; - the need and convenience of maintenance of the equipment. For metal-enclosed switchgear and controlgear containing gas-filled compartments, the design pressure is limited to a maximum of 300 kPa (relative pressure). Metal-enclosed switchgear and controlgear for special use, for example, in flammable atmospheres, in mines or on board ships, may be subject to additional requirements. Components contained in metal-enclosed switch...

  3. High-voltage switchgear and controlgear part 200 : AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV

    CERN Document Server

    International Electrotechnical Commission. Geneva

    2003-01-01

    Specifies requirements for factory-assembled metal-enclosed switchgear and controlgear for alternating current of rated voltages above 1 kV and up to and including 52 kV for indoor and outdoor installation, and for service frequencies up to and including 60 Hz. Enclosures may include fixed and removable components and may be filled with fluid (liquid or gas) to provide insulation. This standard defines several types of metal enclosed switchgear and controlgear which differ due to - the consequences on network service continuity in case of maintenance on the switchgear and controlgear; - the need and convenience of maintenance of the equipment. For metal-enclosed switchgear and controlgear containing gas-filled compartments, the design pressure is limited to a maximum of 300 kPa (relative pressure). Metal-enclosed switchgear and controlgear for special use, for example, in flammable atmospheres, in mines or on board ships, may be subject to additional requirements. Components contained in metal-enclosed switch...

  4. Metal-enclosed air-insulated switchgear for the use in railway power supply systems; Metallgekapselte, luftisolierte Bahnstromschaltanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Loenard, D.; Northe, J. [Balfour Beatty Rail GmbH Power Systems, Offenbach (Germany); Blecher, U. [Ritter Starkstromtechnik GmbH und Co. KG, Geschaeftsbereich Anlagen und Werk fuer Schaltanlagen, Olfen (Germany)

    2004-07-01

    The medium-voltage switchgear of type TracFeed TAC has been designed for the use in standard, booster (1AC) and autotransformer (2AC) 25 kV 50/60 Hz railway power supply systems. This railway switchgear is of metal-enclosed air-insulated design and has been type tested according to EN 62271-200. It meets the special requirements described in the paper entitled ''Requirements on medium-voltage switchgear for railway power supply'' published in No. 10/2003. (orig.)

  5. Discharge Diagnosis of Metal-enclosed Switchgear by Using TEV Method%Discharge Diagnosis of Metal-enclosed Switchgear by Using TEV Method

    Institute of Scientific and Technical Information of China (English)

    REN Ming; DONG Ming; REN Zhong; PENG Hua-dong; LI Hong-jie; QIU Ai-ci

    2011-01-01

    In order to solve the problems of TEV (transient earth voltage) utilization, such as single judgment criterion and low reliability of PD detection in HV switchboard, this paper discussed the method on how to make a better utilization of TEV in PD detection of metal-enclosed switchgears. Through discussing the relationship among the temporal phase, number of pulses and threshold of measuring and extracting the features corresponding to different typical defects, test results showed that the needle discharge distributed in 0°-90° and 200°-340° with low appearance probability above high measurement threshold; internal discharge distributed in 0°-90° and 270°-315°, and showed a similar decreasing trend under increasing of the threshold in the two regions; suspended discharge distributed in 0°- 135° and 180°-315° where the PD in negative half periods decreased more seriously than those in positive half with increasing threshold. These results followed the doctrine of consistency with the conclusions that were obtained by using the traditional pulse current method. The possibility of using TEV method to make identification of PD defects has been proved to prepare foriurther research. Key words: metal-enclosed switchgear; identification of defects; transient earth voltage(TEV) ; PD detection

  6. 1100kV/63kA气体绝缘金属封闭开关设备的研制%Development and Implementation of Gas-Insulated Metal-Enclosed Switchgear With Breaking Capability of 63 kA for 1 100 kV AC Power Transmission Project

    Institute of Scientific and Technical Information of China (English)

    郭媛媛; 崔博源; 王承玉; 孙岗

    2011-01-01

    The gas-insulated metal-enclosed switchgear (GIS) is the most important control and protection equipment in 1 100 kV power grid and it plays important role of ensuring secure and stable operation and reliable power supply of UHVAC power grid. In view of the fact that GIS with breaking capability of 50 kA for 1 100 kV pilot power transmission project cannot meet the requirement of switching-off the short-circuit current of 63 kA, to meet the requirement of constructing UHV power grids in future, it is necessary to develop the GIS with breaking capability of 63 kA. On the basis of researching and analyzing existing UHV power transmission technologies home and abroad, the overall process of developing 1 100 kV GIS with breaking capability of 63 kA is systemically expounded in aspects of power grid demand, simulation analysis, structural design and type test. The core components of the 1 100 kV GIS with breaking capability of 63 kA are calulated and analyzed theoretically, and the structures of circuit breakers with two-contact and four-contact respectively are designed and simulative verifications of them are performed. After scheme comparison, a scheme to meet the requirement of type test for 1 100 kV GIS with breaking capability of 63 kA is proposed. Finally, according to national standard the type test of circuit breaker with four-contact and that with two-contact are completed. Type test results show that the development and manufacturing of GIS with breaking capability of 63 kA for 1 100 kV power grid can be utterly implemented.%1100kV气体绝缘金属封闭开关设备(gas—insulated metal-enclosed switchgear,GIS)是特高压电网中最重要的控制和保护设备,对确保特高压电网的安全稳定运行和可靠供电起着重要作用。特高压交流试验示范工程用1100kV/50kAGIS设备已不能达到开断系统短路电流63kA的要求,为满足未来特高压电网建设需求必须研制出1100kV/63kAGIS设备。分析并

  7. Miniaturization of SF6 Gas-insulated Metal-enclosed Switchgear Design and Development%小型化SF6气体绝缘金属封闭开关设备的设计与研发

    Institute of Scientific and Technical Information of China (English)

    王彬翰; 郭云鹏; 杨升

    2015-01-01

    SF6 gas-insulated metal-enclosed switchgear is also known as SF6 gas enclosed electric; it is widely used in more than 72.5 kV power systems. From the SF6 gas-insulated metal-enclosed switchgear basic content is analyzed using numerical analysis and simulation software to optimize measures miniaturization SF6 gas-insulated metal-enclosed switchgear designed to provide a reference for related research.%SF6气体绝缘金属封闭开关设备又被称为SF6气体封闭式组合电器,它被广泛应用于72.5 kV以上的电力系统中。从 SF6气体绝缘金属封闭开关设备的基本内容出发,分析了采用数值分析和仿真软件实现小型化 SF6气体绝缘金属封闭开关设备设计的优化措施,以期为相关研究提供一定的参考。

  8. Discussion of External Fasteners Selection of Outdoor Gas Insulated Metal-Enclosed Switchgear Gas Chamber%户外GIS气室外用紧固件的选用

    Institute of Scientific and Technical Information of China (English)

    陈伯荣; 俞慧忠; 周庆清; 黄志强

    2014-01-01

    针对户外气体绝缘金属封闭开关设备气室外用紧固件的生锈问题,分析了现阶段碳钢紧固件常用的三种表面防锈防腐处理措施热浸镀锌和达克罗特性及不锈钢材质紧固件的特性,讨论了紧固件设计安装时应注意的事项,并比较了这三类紧固件的防锈防腐特性,综合考虑成本等因素后,给出了户外气体绝缘金属封闭开关设备气室外用紧固件比较经济合理的选用方案。%Aiming at the rust problems of external fasteners of outdoor gas insulated metal-enclosed switchgear (GIS) gas chamber, this paper analyzed hot dip galvanizing, the surface rust and corrosion prevention measure commonly used for the existing carbon steel fasteners and the characteristics of Dacromet and stainless steel fasteners. This paper discussed the caution items of fastener design and installation and compared the rust and corrosion prevention characteristics of three kinds of fasteners. Combined with con-sideration of cost etc factors, this paper gives the economic and reasonable selection plan of external fasteners of GIS gas chamber.

  9. Application of High-Voltage Presence Indication System in Gas Insulated Metal-Enclosed Switchgear%高压带电显示装置在GIS中的应用

    Institute of Scientific and Technical Information of China (English)

    高二平

    2016-01-01

    介绍了高压带电显示装置在SF6气体绝缘金属封闭式组合电器(GIS)上的应用,阐述了其工作原理及在GIS上实现的结构型式,并对比了高压带电显示装置的IEC标准、国家标准及行业标准的差异,总结了高压带电显示装置在GIS实际应用过程中出现的问题及影响因素,为GIS上使用高压带电显示装置提供了参考。%Introduction was made to the application of high-voltage presence indication device in SF6 gas insulated metal-enclosed switchgear (GIS). This paper expounded on its working principle and the realized structural style in GIS, compared the difference among the relevant IEC, GB and DL standards of high-voltage presence indication device and summarized the arisen problems and influence factors in the practical application process of GIS in high-voltage presence indication device, to provide references for the application of high-voltage presence indication device in GIS.

  10. Operating experience with factory-made air-insulated 1AC/2AC switchgear systems; Erste Betriebserfahrungen mit fabrikgefertigten, luftisolierten 1AC-/2AC-Schaltanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Northe, J. [Balfour Beatty Rail GmbH, Offenbach (Germany); Loenard, D. [Bombardier Transportation GmbH, Mannheim (Germany)

    2007-07-01

    Today, factory-made air-insulated switchgear systems of the type TracFeed {sup registered} are available for all supply versions of 16.7 Hz and 50 Hz a.c. railways. These are supported by auxiliary equipment to ensure reliable railway operation through specific protective functions and a simplified line test. (orig.)

  11. New switchgear concepts for a.c. railway applications; Neue Schaltanlagenkonzepte fuer AC-Bahnanwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Loenard, D.; Northe, J. [Balfour Beatty Rail GmbH Power Systems, Offenbach (Germany); Stollberg, A. [VA TECH SAT GmbH, Waltershausen (Germany)

    2005-04-15

    The power supply of electrified railway lines has been provided by well-tried supply systems of different rated voltage levels which require a switchgear with one or two-pole insulation and have resulted in various designs also with respect to the insulation concept. The newly developed branch-based line testing system in conjunction with the enlarged TracFeed {sup registered} series introduced earlier [1] makes it possible to further reduce the size of the switchgear and its buildings. (orig.)

  12. Distribution switchgear

    CERN Document Server

    Stewart, Stan

    2004-01-01

    Switchgear plays a fundamental role within the power supply industry. It is required to isolate faulty equipment, divide large networks into sections for repair purposes, reconfigure networks in order to restore power supplies and control other equipment.This book begins with the general principles of the Switchgear function and leads on to discuss topics such as interruption techniques, fault level calculations, switching transients and electrical insulation; making this an invaluable reference source. Solutions to practical problems associated with Distribution Switchgear are also included.

  13. Compact 40 kA 16,7 Hz switchgear for traction power supply; Kompakte 40-kA-Bahnschaltanlage fuer AC 15 kV 16,7 Hz

    Energy Technology Data Exchange (ETDEWEB)

    Kinscher, Jochen [Siemens AG, Erlangen (DE). Industry Sector Mobility Div. Complete Transportation (I MO CT); Jentzsch, Peter [Siemens AG, Berlin (DE). Industry Sector Mobility Div. Complete Transportation Power Supply Germany (I MO CT EL P)

    2011-10-15

    The air-insulated medium-voltage switchgear Sitras {sup registered} ASG 15 is the first type-tested compact switchgear that can be used in AC 15 kV 16,7 Hz traction power supplies with up to 40 kA short-circuit currents. Therefore, it meets all the demands on prefabricated switchgears for railway applications that railway system operators today are focusing on and is a best practice example for a successful adaption of components designed for the 50 Hz technology for 16,7 Hz traction power supplies. (orig.)

  14. Switchgear condition monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Budyn, M. [ABB Corporate Research, Krakow (Poland); Karandikar, H.M.; Urmson, M.G. [ABB Inc., Lake Mary, FL (United States)

    2010-07-01

    Electric utilities strive to keep switchgear in proper condition over their long life. Medium voltage switchgear are one of the key components in electrical power systems used to distribute electrical power, selectively isolate electrical loads and protect loads from cascading failure. They generally include a combination of electrical elements such as disconnectors, fuses, circuit breakers and distribution bus bars arranged in a lineup of frames. Since switchgear distributes electrical current, heat buildup becomes an important characteristic to monitor. The most significant amount of heat dissipation is on distribution elements like bus bars. Unexpected temperature rise at a particular location may indicate corrosion or a defect. If left uncorrected, this defect could result in catastrophic failure resulting in deactivated loads and potentially hazardous conditions to personnel. Currently, switchgear bus temperature monitoring is done periodically by manual inspections using IR cameras or by fibre-optic systems. Both methods have limitations, such as inaccurate and infrequent readouts, high implementation cost and limited monitoring area. This paper presented a modern approach for condition monitoring based on passive, SAW-based, wireless sensors, reducing installation costs and enhancing monitoring by allowing measurements in previously unreachable locations. A practical implementation of the wireless condition monitoring system was illustrated as a part of a general, built-in, switchgear diagnostics and maintenance system. The use of miniature SAW sensors proved effective in monitoring breaker connectors and non-invasive installation inside the switchgear. 8 refs., 5 figs.

  15. 30 CFR 56.12026 - Grounding transformer and switchgear enclosures.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding transformer and switchgear enclosures... MINES Electricity § 56.12026 Grounding transformer and switchgear enclosures. Metal fencing and metal buildings enclosing transformers and switchgear shall be grounded....

  16. 30 CFR 57.12026 - Grounding transformer and switchgear enclosures.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding transformer and switchgear enclosures... NONMETAL MINES Electricity Surface and Underground § 57.12026 Grounding transformer and switchgear enclosures. Metal fencing and metal buildings enclosing transformers and switchgear shall be grounded....

  17. Requirements on medium-voltage switchgear for traction power supply; Anforderungen an Mittelspannungsschaltanlagen zur Bahnenergieversorgung

    Energy Technology Data Exchange (ETDEWEB)

    Girbert, K.H.; Loenard, D.; Northe, J. [Balfour Beatty Rail GmbH Power Systems, Offenbach (Germany)

    2003-10-01

    Differing requirements to be met by medium-voltage switchgear in conjunction with historical developments, applicable standards and regulations and customers' conditions of operation were the factors responsible for the use of open-air switchgear in outdoor and air-insulated and gas-insulated equipment in indoor environments. The requirements made today on single-phase equipment and two-phase equipment for feeding autotransformer systems are described. Priority focus in the article is given to 25 kV 50 Hz applications though the information applies to 1 AC 15 kV 16.7 Hz equipment in principle as well. The equipment is compared with that used for d.c. railways and public power supply systems. (orig.)

  18. TEV和UHF在10kV开关柜带电检测中的应用%Application of TEV and UHF in PD Detection for the Live 10 kV Switchgear

    Institute of Scientific and Technical Information of China (English)

    曾雄杰; 江健武; 侯俊

    2012-01-01

    10、35 kV金属封闭式开关柜在变电站广泛使用,其运行安全直接影响整个变电站的供电可靠性.因此,对开关柜运行状态的监测及对故障的预判和合理检修是保证开关设备安全可靠运行的关键.笔者介绍了10 kV开关柜局部放电带电测试的TEV和UHF原理,并且成功检测出了深圳某变电站10 kV 2BM、3BM过渡CT柜532BCT柜存在局部放电信号,同时通过对532BCT柜的停电检查,发现532BCT柜中的隔离开关A相静触头是产生局部放电信号的源头所在,从而验证了采用TEV和UHF这两种原理相结合的方式检测10 kV开关柜故障的有效性,为较早地发现10 kV开关柜中的设备缺陷提供了有效检测方法和依据.%Metal-enclosed switchgear rated voltage 10, 35 kV in substations are widely used, which operating security directly affects the supply reliability of substation. Therefore, switchgear operating state monitoring, fault prejudging and reasonable overhaul are the key to guarantee safe and reliable operation of switchgear. The paper explains the principle of TEV and UHF in detecting 10 kV switchgear PD signal respectively. And it also shows the successful application of these two methods in detecting and discovering PD signal on 10 kV 532BCT switchgear of one station. Open and check the equipment, the PD signal has been found on 532BCT disconnecting switch of phase A. This example proves that the combination of both methods is effective in detecting switchgear defect and provides effective methods and basis for finding defects in 10 kV switchgear.

  19. Intelligent MV Switchgear as an Element of Smart Grid Network

    Directory of Open Access Journals (Sweden)

    Janusz Ropa

    2015-12-01

    Full Text Available In the paper the family of intelligent switchgears, developed by a consortium formed by Tele and Radio Research Institute, Transformex sp. o.o., Elektromontaż Lublin and Łódź University of Technology, has been presented as an element of a Smart Grid power network. The switchgear has been equipped with innovative, hybrid current-voltage transducers made using multilayer printed circuit board technology. In the paper the concept of the switchgear, the construction of the transducers and the electronic module integrating the transducer with protection relay input circuit have been described. The intelligent bay controller implemented in the switchgear contains several modules such as Smart Metering, Smart Control, Smart Communication (IEC 61850 and integrates easily with Smart Grid power networks. The bay controller is additionally equipped with a circuit breaker (CB diagnostics module (Smart Diagnostics, which analyses CB parameters during its operation. It generates early warning signals about imminent failure likely to happen between periodic inspections and in this way enhances the reliability and safety of network operation. The switchgear contains also the fault recorder and criterion recorder (Smart Recorder/Logger, that facilitates diagnosing the failure events.

  20. Simulation Analysis of Transient Earth Voltages Aroused by Partial Discharge in Switchgear

    Directory of Open Access Journals (Sweden)

    Man Yuyan

    2014-01-01

    Full Text Available The authors investigated the properties of Transient Earth Voltages (TEV Aroused by Partial Discharge in Switchgear by Simulation. The mechanism of TEV aroused by partial discharge in switchgears is analyzed. The Finite Integration Theory (FIT was employed to simulate the propagation of TEV in the switchgear. The simulation results show that the pulse width of TEV increases as the pulse width of PD pulse increases and the amplitude of TEV is proportional to the PD pulse amplitude. There are time differences between the TEV signals of different detecting points when the TEV propagating on the switchgear’s surface. Based on the simulation, a method of locating the PD of switchgear is proposed by positioning multi-sensors on the external surface of switchgear.

  1. GG-1A型开关柜由架空出线改造为电缆出线的方案%Schemes for converting overhead-outlet metal-enclosed switchgear type GG-1A into cable-outlet switchgear

    Institute of Scientific and Technical Information of China (English)

    黄伟雄

    2005-01-01

    随着配电网改造的深入,许多架空出线已逐步改造为电缆出线.针对GG-1A型架空出线开关柜在运行中可能出现的故障隐患,介绍了几种比较经济易行的电缆出线改造方案,并提出了改造方案实施过程中的技术要点.

  2. Trends of the technology for gas insulated switchgear

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Koji; Daimon, Goro; Yamagiwa, Tokio; Endo, Fumihiro

    1988-08-25

    This is the introduction of the recent technology for gas insulated switchgears. Analysis, detection, and survey technologies from the development stage to the operation stage have made progresses. The third dimension analysis technology makes it possible to make high resolution analysis of asymmetric parts, and the analysis of insulating gas heat flow at the time of high electric current flow. Partial discharge of electricity and supersonic waves have made possible the highly sensitive detection of conductive debris to secure the SF/sub 6/ gas insulation. Lightning surge observation system has been developed and is reflected in the coordination of insulation technology. Application of these technologies to predicative maintenance is also studied. An air shelter was developed to prevent the invasion of debris at the time of assembling on the spot, and for the last examination an impulse testing device is used to confirm the insulation. So far 8,000 gas circuit breakers have been supplied; the coltage was heightened to 550kV and the capacity was augmented to 63kA; and the breaking efficiency leaped high thanks to the improvement of arc extinguish chambers and to the development of new insulating material. Noise was abated, and the breaking capacity per one point has been augmented, so the number of breaking points has been abated. Miniaturization of the switchgear has been materialized by the completion of the all three phase package type. (17 figs, 6 refs)

  3. DC switchgear for the Beijing Metro line 15; Gleichstromschaltanlagen fuer die Metro Peking

    Energy Technology Data Exchange (ETDEWEB)

    Klinge, Ralf [Tianjin BB Electric JV. Ltd. (China); Walter, Mike [Balfour Beatty Rail GmbH, Offenbach (Germany)

    2010-08-15

    The new DC switchgear of type TracFeed {sup registered} TDx is intended for the use in traction power supply sys-tems of DC 750 V and DC 1500 V rated voltage. It is a continuously further developed version of a switchgear unit that has been successfully used since a number of years and is of compact, air-insulated and type-tested design. After it has been used in various applications in Germany this switchgear unit will for the fi rst time be employed in a large scale in the Beijing Metro line 15 project with 21 substations. (orig.)

  4. Temperature Rise Comparison of Switchgear in SF6, N2, and Air

    Directory of Open Access Journals (Sweden)

    Feng Hao

    2013-01-01

    Full Text Available Based on the heat conduction equation, fluid flow governing equation and radiation heat transfer equation, a multi-physics coupled mathematical model is established, the convection heat transfer problem between solid and fluid is solved by wall function. The three dimensional thermal field in a type of switchgear filled respectively with SF6, N2, and air are calculated and analyzed to discuss the feasibility of using air or N2 as the substitution of SF6 by the finite volume method. The results show that the temperature field in three gases are similar in the switchgear. The temperature rise of current-carrying loop is the highest in SF6 and is the lowest in the air. So the conclusion could be made that air or N2 can replace SF6 as the insulating gas of switchgear on the perspective of temperature rise.

  5. High energy arcing fault fires in switchgear equipment : a literature review.

    Energy Technology Data Exchange (ETDEWEB)

    Nowlen, Steven Patrick; Brown, Jason W.; Wyant, Francis John

    2008-10-01

    In power generating plants, switchgear provide a means to isolate and de-energize specific electrical components and buses in order to clear downstream faults, perform routine maintenance, and replace necessary electrical equipment. These protective devices may be categorized by the insulating medium, such as air or oil, and are typically specified by voltage classes, i.e. low, medium, and high voltage. Given their high energy content, catastrophic failure of switchgear by means of a high energy arcing fault (HEAF) may occur. An incident such as this may lead to an explosion and fire within the switchgear, directly impact adjacent components, and possibly render dependent electrical equipment inoperable. Historically, HEAF events have been poorly documented and discussed in little detail. Recent incidents involving switchgear components at nuclear power plants, however, were scrupulously investigated. The phenomena itself is only understood on a very elementary level from preliminary experiments and theories; though many have argued that these early experiments were inaccurate due to primitive instrumentation or poorly justified methodologies and thus require re-evaluation. Within the past two decades, however, there has been a resurgence of research that analyzes previous work and modern technology. Developing a greater understanding of the HEAF phenomena, in particular the affects on switchgear equipment and other associated switching components, would allow power generating industries to minimize and possibly prevent future occurrences, thereby reducing costs associated with repair and downtime. This report presents the findings of a literature review focused on arc fault studies for electrical switching equipment. The specific objective of this review was to assess the availability of the types of information needed to support development of improved treatment methods in fire Probabilistic Risk Assessment (PRA) for nuclear power plant applications.

  6. Investigation on Preventing SF6 Gas Liquefaction For Gas Insulated Metal-enclosed Switchgear in Alpine Regin%严寒地区防止全封闭组合电器SF6气体液化的方案探讨

    Institute of Scientific and Technical Information of China (English)

    李强

    2015-01-01

    阐述了252kV GIS在户外严寒地区运行时,为防止SF6气体液化所采取的措施.设计了三种不同结构的加热器,并分别计算了加热器的功率,用试验验证了加热器的效果,解决了252kVGIS在高寒地区SF6气体液化的问题.

  7. Study on the characteristic decomposition components of air-insulated switchgear cabinet under partial discharge

    Science.gov (United States)

    Gui, Yingang; Zhang, Xiaoxing; Zhang, Ying; Qiu, Yinjun; Chen, Lincong

    2016-07-01

    Air-insulated switchgear cabinet plays a critical role in entire power transmission and distribution system. Its stability directly affects the operational reliability of the power system. And the on-line gas detection method, which evaluates the insulation status of insulation equipment by detecting the decomposition components of filled air in cabinet, becomes an innovative way to ensure the running stability of air-insulated switchgear cabinet. In order to study the characteristic gas types and production regularity of decomposition components under partial discharge, three insulation defects: needle-plate, air-gap and impurity defect are proposed to simulate the insulation defects under partial discharge in air-insulated switchgear cabinet. Firstly, the generation pathways and mechanism of composition components are discussed. Then CO and NO2 are selected as the characteristic decomposition components to characterize the partial discharge due to their high concentration and chemical stability. Based on the different change regularity of CO and NO2 concentration under different insulation defect, it provides an effective way to evaluate and predict the insulation defect type and severity in the field.

  8. Study on the Application of an Ultra-High-Frequency Fractal Antenna to Partial Discharge Detection in Switchgears

    Directory of Open Access Journals (Sweden)

    Chenguo Yao

    2013-12-01

    Full Text Available The ultra-high-frequency (UHF method is used to analyze the insulation condition of electric equipment by detecting the UHF electromagnetic (EM waves excited by partial discharge (PD. As part of the UHF detection system, the UHF sensor determines the detection system performance in signal extraction and recognition. In this paper, a UHF antenna sensor with the fractal structure for PD detection in switchgears was designed by means of modeling, simulation and optimization. This sensor, with a flat-plate structure, had two resonance frequencies of 583 MHz and 732 MHz. In the laboratory, four kinds of insulation defect models were positioned in the testing switchgear for typical PD tests. The results show that the sensor could reproduce the electromagnetic waves well. Furthermore, to optimize the installation position of the inner sensor for achieving best detection performance, the precise simulation model of switchgear was developed to study the propagation characteristics of UHF signals in switchgear by finite-difference time-domain (FDTD method. According to the results of simulation and verification test, the sensor should be positioned at the right side of bottom plate in the front cabinet. This research established the foundation for the further study on the application of UHF technique in switchgear PD online detection.

  9. A New Approach To Inspect the Internal Pressure of Vacuum Switchgear

    Institute of Scientific and Technical Information of China (English)

    LUO Li-wen; ZHAO Zi-yu; LI Hai-yu

    2008-01-01

    A new approach is developed to inspect the internal pressure within the vacuum switchgear by no means of magnet-exciting coil, micro-discharge threshold voltage Ud and field emission threshold voltage Ue, all of which are available in laboratory. Experimental results show that internal pressure is a function of the ratio of the micro-discharge threshold voltage to the field emission threshold voltage i.e., Ud/Ue. By this method, the internal pressure in the range of 100-10-4 Pa within vacuum chambers can be inspected without magnet-exciting coil which is required in conventional magnetron discharge method.

  10. The Research of Mathematical Method and Position Control of Actuator in Power Switchgear

    Directory of Open Access Journals (Sweden)

    Enyuan Dong

    2013-01-01

    Full Text Available Transient effects such as overvoltage and inrush currents will be caused due to opening and closing the switchgear at random phase. Phase-controlled technology present in recent years, which is restricted by the operation dispersion of actuator, can limit the transient effects. And the dispersion of the switchgear with a permanent magnetic actuator (PMA is small. Therefore, the research of mathematical method and position control in this paper is based on the PMA. Firstly, the dynamic mathematical method and simulation system established in MATLAB are used to improve the design of the PMA owing same type. Secondly, simulation with the use of improved fuzzy algorithm is carried out. And an optimized self-adaptive fuzzy algorithm is obtained in the simulation process which can be used to trace the given displacement curve. Finally, a large number of tracing experiments have been done on the 35 kV breaker prototype to verify the effectiveness of the algorithm. In the experiments, the closing time of breaker can be stabilized within ±0.5 ms when capacitor voltage and capacitance change. These results prove that the mathematical model and the fuzzy algorithm are effective and practical.

  11. Abatement cost of SF6 emissions from medium voltage switchgear. Validation of recent studies for the European Commission

    Energy Technology Data Exchange (ETDEWEB)

    Benner, J.; Van Lieshout, M.; Croezen, H.

    2012-05-15

    Sulphur hexafluoride (SF6) is a gas with applications including use as an insulator and switching medium in medium voltage (MV) switchgear. While having certain unique properties, it is also a greenhouse gas, with a 22,800 times greater impact than CO2 and an atmospheric lifetime of over 3,000 years. Although the use of SF6 in MV switchgear can be avoided, according to recent studies for the European Commission, the abatement costs are high. This study validates the calculated cost levels as well as the general feasibility of determining a fixed cost figure for this purpose. This analysis yields a result which differs from the earlier studies, particularly with respect to the cost aspect, but also in other areas. CE Delft concludes that for the majority of applications cost-effective SF6-free options are available, leading to abatement costs for the use of SF6 in MV switchgear that range from - 40 to 0 euro/tCO2 eq., for all types of switchgear, with voltage levels below 25 kV and situated on relatively dry locations.

  12. Aging Management Guideline for commercial nuclear power plants: Electrical switchgear. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Toman, G.; Gazdzinski, R.; Schuler, K. [Ogden Environmental and Energy Services Co., Inc., Blue Bell, PA (United States)

    1993-07-01

    This Aging Management Guideline (AMG) provides recommended methods for effective detection and mitigation of age-related degradation mechanisms in BWR and PWR commercial nuclear power plant electrical switchgear important to license renewal. The latent of this AMG to assist plant maintenance and operations personnel in maximizing the safe, useful life of these components. It also supports the documentation of effective aging management programs required under the License Renewal Rule 10 CFR Part 54. This AMG is presented in a manner which allows personnel responsible for performance analysis and maintenance, to compare their plant-specific aging mechanisms (expected or already experienced) and aging management program activities to the more generic results and recommendations presented herein.

  13. MV gasinsulated switchgear and controlgear progressing; Gasisolierte MS-Schaltanlagen auf dem Vormarsch

    Energy Technology Data Exchange (ETDEWEB)

    Brueggemann, G. [Schneider Electric GmbH, Ratingen (Germany). Produktmarketing Mittelspannung

    1998-08-24

    Gasinsulated switchgear and controlgear (GIS) are getting more and more importance in medium voltage range. Significant for this is that differences in price are becoming smaller in comparison to airinsulated technology with further improvements of the GIS primary part (switch-unit). In parallel attractive improvement of capability is given by using pre-defined combinations with relevant secondary equipment (protection, control and monitoring systems). The author summarizes the basic steps for this development and explains them using as example the newest solutions. (orig.) [Deutsch] Gasisolierte Schaltanlagen (GIS) erlangen in der Mittelspannung eine immer groessere Bedeutung. Kennzeichnend dafuer ist zum einen, dass die Preisunterschiede zur vergleichbaren luftisolierten Technik immer geringer werden. Zum anderen zeigen sich parallel zur kontinuierlichen Weiterentwicklung der GIS-Primaertechnik (Schaltfelder) attraktive Leistungsverbesserungen durch vorentwickelte Kombinationen mit der zugehoerigen Sekundaertechnik (Schutz-, Steuer- und Ueberwachungseinrichtungen). Der Verfasser fasst die grundlegenden Schritte dieser Entwicklung zusammen und konkretisiert sie am Beispiel der neuesten Loesungen. (orig.)

  14. Design of a New Built-in UHF Multi-Frequency Antenna Sensor for Partial Discharge Detection in High-Voltage Switchgears

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2016-07-01

    Full Text Available In this study a new built-in ultrahigh frequency (UHF antenna sensor was designed and applied in a high-voltage switchgear for partial discharge (PD detection. The casing of the switchgear was initially used as the ground plane of the antenna sensor, which integrated the sensor into the high-voltage switchgear. The Koch snowflake patch was adopted as the radiation patch of the antenna to overcome the disadvantages of common microstrip antennas, and the feed position and the dielectric layer thickness were simulated in detail. Simulation results show that the antenna sensor possessed four resonant points with good impedance matching from 300 MHz to 1000 MHz, and it also presented good multi-frequency performance in the entire working frequency band. PD detection experiments were conducted in the high-voltage switchgear, and the fabricated antenna sensor was effectively built into the high-voltage switchgear. In order to reflect the advantages of the built-in antenna sensor, another external UHF antenna sensor was used as a comparison to simultaneously detect PD. Experimental results demonstrated that the built-in antenna sensor possessed high detection sensitivity and strong anti-interference capacity, which ensured the practicability of the design. In addition, it had more high-voltage switchgear PD detection advantages than the external sensor.

  15. Design of a New Built-in UHF Multi-Frequency Antenna Sensor for Partial Discharge Detection in High-Voltage Switchgears.

    Science.gov (United States)

    Zhang, Xiaoxing; Cheng, Zheng; Gui, Yingang

    2016-07-26

    In this study a new built-in ultrahigh frequency (UHF) antenna sensor was designed and applied in a high-voltage switchgear for partial discharge (PD) detection. The casing of the switchgear was initially used as the ground plane of the antenna sensor, which integrated the sensor into the high-voltage switchgear. The Koch snowflake patch was adopted as the radiation patch of the antenna to overcome the disadvantages of common microstrip antennas, and the feed position and the dielectric layer thickness were simulated in detail. Simulation results show that the antenna sensor possessed four resonant points with good impedance matching from 300 MHz to 1000 MHz, and it also presented good multi-frequency performance in the entire working frequency band. PD detection experiments were conducted in the high-voltage switchgear, and the fabricated antenna sensor was effectively built into the high-voltage switchgear. In order to reflect the advantages of the built-in antenna sensor, another external UHF antenna sensor was used as a comparison to simultaneously detect PD. Experimental results demonstrated that the built-in antenna sensor possessed high detection sensitivity and strong anti-interference capacity, which ensured the practicability of the design. In addition, it had more high-voltage switchgear PD detection advantages than the external sensor.

  16. Proposal for the award of a contract, without competitive tendering, for the maintenance of low-voltage switchgear

    CERN Document Server

    2003-01-01

    This document concerns the award of a contract, without competitive tendering, for the maintenance of low-voltage switchgear. The Finance Committee is invited to agree to the negotiation of a contract, without competitive tendering, for the maintenance of low-voltage switchgear with HAZEMEYER (FR) for a total amount of 385 000 euros (610 000 Swiss francs), covering an initial period of five years, subject to revision for inflation after 1 January 2007. The contract will include options for two one-year extensions beyond the initial five-year period. The amount in Swiss francs has been calculated using the present rate of exchange. The firm has indicated the following distribution by country of the contract value covered by this adjudication proposal: FR - 100%.

  17. SIMPLIFIED METHOD FOR CALCULATING CLOSING IN OF SWITCH-GEAR FLEXIBLE BUSES AT SHORT CIRCUIT BY IMPULSE OF ELECTRODYNAMIC FORCES

    OpenAIRE

    I. I. Sergey; E. G. Ponomarenko; W. M. Sammur; P. I. Klimkovich

    2005-01-01

    The paper contains description of a simplified method for calculating closing-in of switch-gear flexible buses at short circuit. The developed method is based on integral and energy principles of  mechanics. In order to increase accuracy of the calculation corrections factors are introduced in an explicit formula for calculation of maximum horizontal deviations. These factors have been obtained with the help of a computer program that realized numerical method for calculating closing-in of wi...

  18. Monitoring system applicable for 3-phase encapsulated switchgears; Monitoringsystem fuer dreiphasig gekapselte gasisolierte HV-Schaltanlagen. Neuer Kommunikationsstandard IEC 61850

    Energy Technology Data Exchange (ETDEWEB)

    Glock, J.; Heinemann, L. [ABB AG, Mannheim (Germany)

    2008-02-25

    The monitoring system presented is applicable for 3-phase encapsulated switchgears. It helps to reduce maintenance costs by continuous supervision of primary and secondary equipment. Inspection intervals can be increased and maintenance effort is reduced. Maintenance planning is supported by remaining life time determination and trend analysis. In the unlikely case of a failure the system allows fast and easy access to all relevant information for fault localization and counter-measures. (orig.)

  19. 10 CFR 830 Major Modification Determination for the ATR Diesel Bus (E-3) and Switchgear Replacement

    Energy Technology Data Exchange (ETDEWEB)

    Noel Duckwtiz

    2011-05-01

    Near term replacement of aging and obsolescent original ATR equipment has become important to ensure ATR capability in support of NE’s long term national missions. To that end, a mission needs statement has been prepared for a non-major system acquisition which is comprised of three interdependent subprojects. The first project, subject of this determination, will replace the existent diesel-electrical bus (E-3) and associated switchgear. More specifically, INL proposes transitioning ATR to 100% commercial power with appropriate emergency backup to include: • Provide commercial power as the normal source of power to the ATR loads currently supplied by diesel-electric power. • Provide backup power to the critical ATR loads in the event of a loss of commercial power. • Replace obsolescent critical ATR power distribution equipment, e.g., switchgear, transformers, motor control centers, distribution panels. Completion of this and two other age-related projects (primary coolant pump and motor replacement and emergency firewater injection system replacement) will resolve major age related operational issues plus make a significant contribution in sustaining the ATR safety and reliability profile. The major modification criteria evaluation of the project pre-conceptual design identified several issues make the project a major modification: 1. Evaluation Criteria #2 (Footprint change). The addition of a new PC-4 structure to the ATR Facility to house safety-related SSCs requires careful attention to maintaining adherence to applicable engineering and nuclear safety design criteria (e.g., structural qualification, fire suppression) to ensure no adverse impacts to the safety-related functions of the housed equipment. 2. Evaluation Criteria #3 (Change of existing process). The change to the strategy for providing continuous reliable power to the safety-related emergency coolant pumps requires careful attention and analysis to ensure it meets a project primary object

  20. SIMPLIFIED METHOD FOR CALCULATING CLOSING IN OF SWITCH-GEAR FLEXIBLE BUSES AT SHORT CIRCUIT BY IMPULSE OF ELECTRODYNAMIC FORCES

    Directory of Open Access Journals (Sweden)

    I. I. Sergey

    2005-01-01

    Full Text Available The paper contains description of a simplified method for calculating closing-in of switch-gear flexible buses at short circuit. The developed method is based on integral and energy principles of  mechanics. In order to increase accuracy of the calculation corrections factors are introduced in an explicit formula for calculation of maximum horizontal deviations. These factors have been obtained with the help of a computer program that realized numerical method for calculating closing-in of wires by flexible thread levels.Diagrams are constructed with the purpose to find ymax and criteria of electro-dynamic resistance of flexible buses (permissible impulse of electro-dynamic forces and current of electro-dynamic resistance is determined.

  1. UHF Signal Processing and Pattern Recognition of Partial Discharge in Gas-Insulated Switchgear Using Chromatic Methodology

    Science.gov (United States)

    Wang, Xiaohua; Li, Xi; Rong, Mingzhe; Xie, Dingli; Ding, Dan; Wang, Zhixiang

    2017-01-01

    The ultra-high frequency (UHF) method is widely used in insulation condition assessment. However, UHF signal processing algorithms are complicated and the size of the result is large, which hinders extracting features and recognizing partial discharge (PD) patterns. This article investigated the chromatic methodology that is novel in PD detection. The principle of chromatic methodologies in color science are introduced. The chromatic processing represents UHF signals sparsely. The UHF signals obtained from PD experiments were processed using chromatic methodology and characterized by three parameters in chromatic space (H, L, and S representing dominant wavelength, signal strength, and saturation, respectively). The features of the UHF signals were studied hierarchically. The results showed that the chromatic parameters were consistent with conventional frequency domain parameters. The global chromatic parameters can be used to distinguish UHF signals acquired by different sensors, and they reveal the propagation properties of the UHF signal in the L-shaped gas-insulated switchgear (GIS). Finally, typical PD defect patterns had been recognized by using novel chromatic parameters in an actual GIS tank and good performance of recognition was achieved. PMID:28106806

  2. THE STUDY ON MEASURING TECHNIQUE OF PARTIAL DISCHARGE IN GAS INSULATED SWITCHGEAR USING ULTRA HIGH FREQUENCY METHOD WITH EXTERNAL SENSORS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Objective In order to find early latent faults and prevent catastrophic failures, diagnosis of insulation condition by measuring technique of partial discharge(PD) in gas insulated switchgear (GIS) is applied in this paper, which is one of the most basic ways for diagnosis of insulation condition. Methods Ultra high frequency(UHF) PD detection method by using internal sensors has been proved efficient, because it may avoid the disturbance of corona, but the sensor installation of this method will be limited by the structure and operation condition of GIS.There are some of electromagnetic (E-M) waves leak from the place of insulation spacer, therefore, the external sensors UHF measuring PD technique is applied, which isn't limited by the operation condition of GIS. Results This paper analyzes propagated electromagnetic (E-M) waves of partial discharge pulse excited by using the finite-difference time-domain (FDTD) method. The signal collected at the outer point is more complex than that of the inner point, and the signals' amplitude of outer is about half of the inner, because it propagates through spacer and insulation slot. Set up UHF PD measuring system. The typical PD in 252kV GIS bus bar was measured using PD detection UHF technique with external sensors. Finally, compare the results of UHF measuring technique using external sensors with the results of FDTD method simulation and the traditional IEC60270 method detection. Conclusion The results of experiment shows that the UHF technique can realize the diagnosis of insulation condition, the results of FDTD method simulation and the result UHF method detection can demonstrate each other, which gives references to further researches and application for UHF PD measuring technique.

  3. AC 410 AC410 AC410 Unit 7 Homework Assignment

    OpenAIRE

    Laynebaril1

    2017-01-01

    AC 410 AC410 AC410 Unit 7 Homework Assignment Click Link Below To Buy: http://hwcampus.com/shop/ac410-unit-7-homework-assignment/    Questions Requiring Analysis 14-30   Early in your first audit of Star Corporation, you notice that sales and year-end inventory are almost unchanged from the prior year. However, cost of goods sold is less than in the preceding year, and accounts payable also are down substantially. Gross profit has increased, but this increase has not c...

  4. Peltier ac calorimeter

    OpenAIRE

    Jung, D. H.; Moon, I. K.; Jeong, Y. H.

    2001-01-01

    A new ac calorimeter, utilizing the Peltier effect of a thermocouple junction as an ac power source, is described. This Peltier ac calorimeter allows to measure the absolute value of heat capacity of small solid samples with sub-milligrams of mass. The calorimeter can also be used as a dynamic one with a dynamic range of several decades at low frequencies.

  5. ACAC Converters for UPS

    Directory of Open Access Journals (Sweden)

    Rusalin Lucian R. Păun

    2008-05-01

    Full Text Available This paper propose a new control technique forsingle – phase ACAC converters used for a on-line UPSwith a good dynamic response, a reduced-partscomponents, a good output characteristic, a good powerfactorcorrection(PFC. This converter no needs anisolation transformer. A power factor correction rectifierand an inverter with the proposed control scheme has beendesigned and simulated using Caspoc2007, validating theconcept.

  6. Approach for Wide Use of Diagnostic Method for XLPE Cables Using Harmonics in AC Loss Current

    Science.gov (United States)

    Tsujimoto, Tomiyuki; Nakade, Masahiko; Yagi, Yukihiro; Ishii, Noboru

    Water tree is one of the degradation aspects of XLPE cables used for under-ground distribution or transmission lines. We have developed the loss current method using 3rd harmonic in AC loss current for cable diagnosis. Harmonic components in loss current arise as a result of the non-linear voltage-current characteristics of water trees. We confirmed that the 3rd harmonic in AC loss current had good correlation with water tree growth and break down strength. After that, we have applied this method to the actual 66kV XLPE cable lines. Up to now, the number of the application results is more than 130 lines. In case of cable lines terminated at gas-insulated switchgear (GIS), we have to remove the lightning arrestor (LA) and the potential transformer (PT) out of the test circuit. The reason is that we are afraid that each of LA and PT disturbs the degradation signal from cable lines. It takes extra time (1 or 2 days) and costs more to remove LA and PT in GIS out of a circuit. In order to achieve easy and reasonable diagnosis, we have developed a new method for cable lines terminated at GIS, by utilizing a technique, which enables to reduce signal of LA and PT from disturbed signal of cable lines. We confirmed the effect of the new method by experiments with actual cables.

  7. ACS: ALMA Common Software

    Science.gov (United States)

    Chiozzi, Gianluca; Šekoranja, Matej

    2013-02-01

    ALMA Common Software (ACS) provides a software infrastructure common to all ALMA partners and consists of a documented collection of common patterns and components which implement those patterns. The heart of ACS is based on a distributed Component-Container model, with ACS Components implemented as CORBA objects in any of the supported programming languages. ACS provides common CORBA-based services such as logging, error and alarm management, configuration database and lifecycle management. Although designed for ALMA, ACS can and is being used in other control systems and distributed software projects, since it implements proven design patterns using state of the art, reliable technology. It also allows, through the use of well-known standard constructs and components, that other team members whom are not authors of ACS easily understand the architecture of software modules, making maintenance affordable even on a very large project.

  8. High voltage switchgear cabinet based on IoT technology%基于物联网的智能高压开关柜设计

    Institute of Scientific and Technical Information of China (English)

    黄新波; 方寿贤; 王霄宽; 王红亮; 李小博; 李文静

    2013-01-01

    An intelligent high voltage switchgear cabinet is designed based on IoT (Internet of Things) technologies. Its IED(Intelligent Electronic Device) applies dual-CPU(DSP+ARM) structure,which collects the information from the intelligent monitoring unit via CAN bus/485 bus/ZigBee and communicates with the service center of substation control layer for remote monitoring according to IEC61850 protocol. Its intelligent control unit monitors the binary variables, temperature and humidity of cabinet and displays the states of cabinet via LCD screen/highlighted indictor bars/indictor lights. The control unit is also responsible for the electric operation control of cabinet. Device information is assigned as electronic tag inside the device,which is read and transmitted to the IED of cabinet by the intelligent recognition unit using RFID (Radio Frequency IDentification) technology. The received information is further sent to the integrated information platform for device locating and tracking. The intelligent high voltage switchgear cabinet is installed in a substation and operates well.%设计了一种基于物联网技术的智能开关柜.智能开关柜IED采用DSP+ARM双CPU的结构,通过CAN总线、RS-485总线、ZigBee技术等接收智能监测单元监测到的信息,按照IEC61850协议与站控层服务中心进行通信,实现远程监控功能.智能控制单元对柜内开关量、温度、湿度等进行监测,并通过液晶屏、高亮指示条和指示灯显示开关柜状态,同时负责实现开关柜电动操作控制.智能识别单元将设备信息以电子标签的形式预埋在设备中,通过无线射频识别(RFID)技术直接将设备信息传递给智能开关柜IED,由开关柜上传到一体化信息平台,对设备进行准确定位、跟踪.所设计的智能开关柜已成功应用于唐山虹桥变电站,现场工作正常.

  9. A fully enclosed, compact standard lightning impulse generator for testing ultra-high-voltage-class gas-insulated switchgears with high capacitance

    Science.gov (United States)

    Wen, Tao; Zhang, Qiaogen; Zhang, Lingli; Zhao, Junping; Liu, Xuandong; Li, Xiaoang; Guo, Can; You, Haoyang; Chen, Weijiang; Yin, Yu; Shi, Weidong

    2016-03-01

    At present, conducting standard lightning impulse (LI) tests in the field for gas-insulated switchgear (GIS) equipment is difficult because of the high capacitance of the test equipment and large circuit inductance of traditional impulse devices, which leads to a wavefront time Tf ≥ 2.5 μs. A novel fully enclosed, compact standard LI generator for testing ultra-high-voltage-class GIS equipment with high capacitance is presented to solve the problem of Tf exceeding the standard during LI voltage tests for actual large-sized equipment. The impulse generator is installed in a metal vessel filled with SF6 or SF6/N2 gas mixture at a pressure of 0.3-0.5 MPa, providing a more compact structure and a lower series inductance. A newly developed conical voltage sensor is used to accurately measure the output voltage waveform. Two test modes (via bushing docking and direct docking) for the GIS test based on the impulse generator are introduced. Calculation results show that the impulse generator can generate an LI test waveform following the present IEC standard for the test of equipment with capacitance >10 000 pF.

  10. Electrical Locking Analysis of Pushcart Switchgear Cabinet Unit%小车式开关柜单元电气闭锁分析

    Institute of Scientific and Technical Information of China (English)

    陈秋杰; 卢迪勇

    2011-01-01

    Combining with substation site operation procedures and safety requirements of maintenance and taking some factories' 10 kV pushcart switchgear cabinets for examples,this paper described the working principle of mutual interlocks for line-out pushcart,bus%结合变电站现场操作步骤和检修的安全要求,以部分厂家10kV小车式开关柜为例,阐述了出线小车、母线分段小车、主变开关小车、主变隔离小车和接地车的相互联锁的工作原理,比较了其单元电气闭锁流程及特点,对联锁流程作出评价,并总结出一套10kV小车式开关柜操作常规流程,供设计、运行人员参考。

  11. Electric Field Optimization in 170 kV Gas-Insulated Switchgear Spacer based on Non-Uniform Rational B-spline Curve

    Science.gov (United States)

    Han, In Su; Kim, Eung Sik; Min, Suk Won; Hur, Don; Park, Jong Keun

    2004-10-01

    In this paper, the electric field at the spacer in a 170 kV gas-insulated switchgear (GIS) is optimized. Initially, the tangential and total electric fields around the original shape of the 170 kV GIS produced by a Korean company are calculated using a combination of the charge simulation method (CSM) and surface charge method (SCM). The contour of the spacer in the 170 kV GIS is found using a non-uniform rational B-spline (NURB) curve the effectiveness of which has been proved. By moving some control points in the NURB curve, the initial shape of the 170 kV GIS can be determined so that we may begin to optimize the electric field. Owing to the proposed algorithm, the overall process has a stable convergence. The objects that we want to design are the upper and lower parts of the spacer. Finally, we can find the shapes in which the tangential and total electric fields are optimized.

  12. AcEST: DK950971 [AcEST

    Lifescience Database Archive (English)

    Full Text Available GN=... 37 0.66 tr|B1ACS4|B1ACS4_BALBO DMP1 (Fragment) OS=Balaenoptera borealis ... 37 0.66 tr|B1ACS3|B1ACS3...todon GN=DM... 37 1.1 tr|B1ACT4|B1ACT4_LISBO DMP1 (Fragment) OS=Lissodelphis borealis ... 37 1.1 tr|B1ACS2|B...SSSEEEIQSKNTEMESRRLTVDAY 160 >tr|B1ACS4|B1ACS4_BALBO DMP1 (Fragment) OS=Balaenoptera borealis GN=DMP1 PE=4 S

  13. Isolation of sequences flanking Ac insertion sites by Ac casting.

    Science.gov (United States)

    Wang, Dafang; Peterson, Thomas

    2013-01-01

    Localizing Ac insertions is a fundamental task in studying Ac-induced mutation and chromosomal rearrangements involving Ac elements. Researchers may sometimes be faced with the situation in which the sequence flanking one side of an Ac/Ds element is known, but the other flank is unknown. Or, a researcher may have a small sequence surrounding the Ac/Ds insertion site and needs to obtain additional flanking genomic sequences. One way to rapidly clone unknown Ac/Ds flanking sequences is via a PCR-based method termed Ac casting. This approach utilizes the somatic transposition activity of Ac during plant development, and provides an efficient means for short-range genome walking. Here we describe the principle of Ac casting, and show how it can be applied to isolate Ac macrotransposon insertion sites.

  14. Harm and Protection of Arc Fault Inside 10 kV Switchgear%10kV开关柜内部电弧故障的危害与保护

    Institute of Scientific and Technical Information of China (English)

    曾新雄; 李新海; 曾庆祝; 孟晨旭; 肖星; 姚盛华

    2016-01-01

    In allusion to problems that arc fault inside 10 kV switchgear may cause great harm and degree of harm is in pro‐portion to combustion time of electric arc ,a kind of proactive arc protection device for restricting combustion time of inter‐nal electric arc is presented and developed in order to solve problems of long action time and complicated scheme of current protection ,arc protection and breaker clearing electric arc fault .When arc fault occurs inside 10 kV switchgear ,this device may cause three‐phase metallic earth of 10 kV bus with the fault in less than 5 ms by controlling arc quenching unit and con‐sequently extinguish faulted electric arc .Meanwhile ,the device sends out tripping order to the incoming circuit breaker to cut off power supply and isolate fault which may avoid damages of equipments caused by arc fault inside the switchgear ,en‐sure security of field personnel and realize initiative and fast protection for arc fault inside 10 kV switchgear .%针对10 kV开关柜内部电弧故障危害性大,故障危害程度与电弧燃烧时间成正比的特点,为解决现有电流式保护、弧光保护和断路器切除电弧故障的动作时间长、方案复杂等问题,提出并研发了用于限制内部电弧燃烧时间的主动型电弧故障保护装置。当发生10 kV开关柜内部电弧故障时,该装置能在小于5 ms内控制熄弧单元主动将故障所在的10 kV母线进行三相金属性接地,从而熄灭故障电弧,同时该装置发出跳闸命令给进线断路器跳闸,将电源切除,隔离故障,避免了开关柜内部电弧故障造成的设备损坏,保障了现场工作人员的安全,实现了10 kV开关柜内部电弧故障的主动快速防护。

  15. Application of Electric Heating in SF6 Switchgear%电加热方式在SF_6开关设备中的应用

    Institute of Scientific and Technical Information of China (English)

    李松琴

    2012-01-01

    Due to liquefaction of SF6 gas under super low temperature, the SF6 gas density within the SF6 switch equipment comes down, reduced the breaking capacity of SF6 switehgear and insulation level, unable to ensure the reliable operation of SF6 switch device. For this purpose, the writers made use of SF6 in electric heating device on the SF6 switchgear gas heating temperature can be always higher than the SF6 gas liquefaction of SF6 gas temperature of the solution. At the same time, this article on ultra-low temperature environment of the other solutions also analyzed.%由于SF6气体在超低温下产生部分液化,使得SF6开关设备内的SF6气体密度下降,降低了SF6开关设备的开断能力和绝缘水平,无法保证SF6开关设备的可靠运行。为此,本文作者提出了采用电加热装置对SF6开关设备中的SF6气体进行加热,使SF6气体的温度可以始终高于SF6气体液化温度的解决方案。同时,本文对超低温环境下的其他解决方案也进行了分析比较。

  16. AC-3 audio coder

    Science.gov (United States)

    Todd, Craig

    1995-12-01

    AC-3 is a system for coding up to 5.1 channels of audio into a low bit-rate data stream. High quality may be obtained with compression ratios approaching 12-1 for multichannel audio programs. The high compression ratio is achieved by methods which do not increase decoder memory, and thus cost. The methods employed include: the transmission of a high frequency resolution spectral envelope; and a novel forward/backward adaptive bit allocation algorithm. In order to satisfy practical requirements of an emissions coder, the AC-3 syntax includes a number of features useful to broadcasters and consumers. These features include: loudness uniformity between programs; dynamic range control; and broadcaster control of downmix coefficients. The AC-3 coder has been formally selected for inclusion of the U.S. HDTV broadcast standard, and has been informally selected for several additional applications.

  17. Tevatron AC dipole system

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, R.; Kopp, S.E.; /Texas U.; Jansson, A.; Syphers, M.J.; /Fermilab

    2007-06-01

    The AC dipole is an oscillating dipole magnet which can induce large amplitude oscillations without the emittance growth and decoherence. These properties make it a good tool to measure optics of a hadron synchrotron. The vertical AC dipole for the Tevatron is powered by an inexpensive high power audio amplifier since its operating frequency is approximately 20 kHz. The magnet is incorporated into a parallel resonant system to maximize the current. The use of a vertical pinger magnet which has been installed in the Tevatron made the cost relatively inexpensive. Recently, the initial system was upgraded with a more powerful amplifier and oscillation amplitudes up to 2-3{sigma} were achieved with the 980 GeV proton beam. This paper discusses details of the Tevatron AC dipole system and also shows its test results.

  18. High Voltage Switchgear Temperature Acquisition System Based on SAW Sensor Technology Analysis%基于 SAW 传感器技术的高压开关柜温度采集系统设计分析

    Institute of Scientific and Technical Information of China (English)

    郭翠玲; 高丽

    2015-01-01

    根据传统高压开关柜温度采集方法的不足,采用 SAW 传感器技术对高压开关柜进行无源无线温度采集。该系统具有温度测量、报警功能、参数设定、数据存储等功能,对温度进行远程实时在线监测,是智能电网建设的重要依据。%Based on the shortcomings of the traditional method of temperature measurement of high voltage switchgear ,the paper uses SAW sensor technology to take passive wireless temperature measurement for high voltage switchgear .T he system ,w hich has temperature measurement ,alarm function ,parameter setting ,data storage and other functions that can take real - time remote temperature online monito‐ring ,is an important basis for smart grid construction .

  19. AC/RF Superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [JLAB

    2015-02-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  20. 基于小波变换的开关柜电磁干扰分析%Analysis of Switchgear Electromagnetic Interference Based on Wavelet Analysis

    Institute of Scientific and Technical Information of China (English)

    朱晨光; 徐铭辉; 华争祥; 胡可

    2015-01-01

    Transient electromagnetic interference generated in the process of switch equipment running exerts a great influence on the stable operation of the secondary electronic device. To tackle such issues as the ambiguity of the switchgear electromagnetic interference signal characteristics and the inadequacy of secondary circuit noise im-munity competence, the paper proposed a method of using synthetic test circuit and raster isolation acquisition sys-tem to collect electromagnetic interference signals under different operating environments, which was analyzed using wavelet to process interference signals mathematically and to extract the transient electromagnetic interference and the energy distribution of the main band. The results indicate that with the upgrading of the current value of the cir-cuit, electromagnetic interference tend to increase gradually, the electromagnetic interference band being between d4 wavelet 31. 25 MHz and d5 wavelet 7. 8125 MHz. The study lays the foundation for further study of the transient electromagnetic interference mitigation methods to enhance the electromagnetic immunity level of secondary elec-tronic devices.%开关设备运行过程中产生的暂态电磁干扰对二次电子装置的稳定运行有重要的影响。针对目前开关柜电磁干扰信号特征不明确,二次回路抗干扰能力不足的问题,提出了一种利用合成试验回路和光栅隔离采集系统进行不同运行环境下电磁干扰信号采集,利用db小波分析方法对干扰信号进行数学处理并提取出暂态电磁干扰的主要频带及能量分布的方法。研究表明:随着断路器开断电流数值的提升,由开断造成的电磁干扰呈现逐渐增强的态势,干扰电磁波频段为d4小波和d5小波所在的7.8125~31.25MHz频段。为下一步研究暂态电磁干扰抑制方法,提升二次电子装置的电磁抗干扰水平打下了基础。

  1. High performance AC drives

    CERN Document Server

    Ahmad, Mukhtar

    2010-01-01

    This book presents a comprehensive view of high performance ac drives. It may be considered as both a text book for graduate students and as an up-to-date monograph. It may also be used by R & D professionals involved in the improvement of performance of drives in the industries. The book will also be beneficial to the researchers pursuing work on multiphase drives as well as sensorless and direct torque control of electric drives since up-to date references in these topics are provided. It will also provide few examples of modeling, analysis and control of electric drives using MATLAB/SIMULIN

  2. 2000 m海拔35 kV开关柜母排结构安全净距试验研究%Experimental Study on Net Safety Distance of 35 kV Switchgear Bus Structure in 2 000 Meters Altitude

    Institute of Scientific and Technical Information of China (English)

    王磊; 赵现平; 董俊; 徐富良

    2013-01-01

    The phase to phase and phase to ground distances in air to ensure the security of 35 kV switchgear bus are obtained through the rod-plane air gap experiment at the place below of 1 000 meters altitude. In fact, there exists differences between the structure of rod-plane air gap and switchgear bus, and in higher altitude, discharge in air becomes easy due to lower atmospheric pressure. In order to get the net safety distance in 35 kV switchgear at 2 000 meters altitude, switchgear bus structures are classified and the simulation experiment switchgear is designed in this paper. Power frequency voltage and impulse voltage tests are taken to the different structure in 2 000 meters altitude. The minimum distance without discharge, normally called net safety distance, is obtained through experiment in which applied voltage values are in accordance to standard. The results can be referred to switchgear design and manufacture.%35 kV开关柜母排相间、相对地保证安全的空气距离是在1 000 m以下海拔通过对棒—板间隙的试验得出,棒—板间隙结构与开关柜内部母排结构存在差异,同时高海拔地区大气压力降低,空气间隙放电变得容易,为了得到2000m海拔35 kV开关柜的安全净距,文中对开关柜内母排结构进行了分类并设计了模拟试验开关柜,对不同结构母排进行了2000m海拔的工频及冲击放电试验.试验通过对不同结构母排施加标准要求的试验电压值,得到相对应的最小不放电距离即安全净距,为2000m海拔开关柜的设计、制造提供了参考.

  3. AC Optimal Power Flow

    Energy Technology Data Exchange (ETDEWEB)

    2016-10-04

    In this work, we have implemented and developed the simulation software to implement the mathematical model of an AC Optimal Power Flow (OPF) problem. The objective function is to minimize the total cost of generation subject to constraints of node power balance (both real and reactive) and line power flow limits (MW, MVAr, and MVA). We have currently implemented the polar coordinate version of the problem. In the present work, we have used the optimization solver, Knitro (proprietary and not included in this software) to solve the problem and we have kept option for both the native numerical derivative evaluation (working satisfactorily now) as well as for analytical formulas corresponding to the derivatives being provided to Knitro (currently, in the debugging stage). Since the AC OPF is a highly non-convex optimization problem, we have also kept the option for a multistart solution. All of these can be decided by the user during run-time in an interactive manner. The software has been developed in C++ programming language, running with GCC compiler on a Linux machine. We have tested for satisfactory results against Matpower for the IEEE 14 bus system.

  4. Single-Phase Direct AC-AC Boost Converter

    Directory of Open Access Journals (Sweden)

    LUCANU, M.

    2014-08-01

    Full Text Available The paper presents a single-phase direct AC-AC boost converter. The circuit of the converter is simple and it has good performances, irrespective of the load nature. The adequate functioning and high performance of the circuit (the efficiency and waveform of the absorbed input current were tested both by simulation and experimentally.

  5. Cooling Floor AC Systems

    Science.gov (United States)

    Jun, Lu; Hao, Ding; Hong, Zhang; Ce, Gao Dian

    The present HVAC equipments for the residential buildings in the Hot-summer-and-Cold-winter climate region are still at a high energy consuming level. So that the high efficiency HVAC system is an urgently need for achieving the preset government energy saving goal. With its advantage of highly sanitary, highly comfortable and uniform of temperature field, the hot-water resource floor radiation heating system has been widely accepted. This paper has put forward a new way in air-conditioning, which combines the fresh-air supply unit and such floor radiation system for the dehumidification and cooling in summer or heating in winter. By analyze its advantages and limitations, we found that this so called Cooling/ Heating Floor AC System can improve the IAQ of residential building while keep high efficiency quality. We also recommend a methodology for the HVAC system designing, which will ensure the reduction of energy cost of users.

  6. ACS CCD Stability Monitor

    Science.gov (United States)

    Grogin, Norman

    2012-10-01

    A moderately crowded stellar field in the cluster 47 Tuc {6 arcmin West of the cluster core} is observed every four months with the WFC. The first visit exercises the full suite of broad and narrow band imaging filters and sub-array modes; following visits observe with only the six most popular Cycle 18 filters in full-frame mode. The positions and magnitudes of objects will be used to monitor local and large scale variations in the plate scale and the sensitivity of the detectors and to derive an independent measure of the detector CTE. One exposure in each sub-array mode with the WFC will allow us to verify that photometry obtained in full-frame and in sub-array modes are repeatable to better than 1%. This test is important for the ACS Photometric Cross-Calibration program, which uses sub-array exposures. This program may receive additional orbits to investigate ORIENT-dependent geometric distortion, which motivates the ORIENT and BETWEEN requirement on the first visit.

  7. AcEST: DK956383 [AcEST

    Lifescience Database Archive (English)

    Full Text Available TAC +HPGP Sbjct: 130 TP----GQAEEEKIEPLAPPVQKAVIDINQPQVCKNKGCGQTFKERDNHETACSHHPGPA 185 Query: 574 VF 579 VF S...AC +HPGP Sbjct: 130 TP----GQAEEEKIEPLAPPVQKAVIDINQPQVCKNKGCGQTFKERDNHETACSHHPGPA 185 Query: 574 VF 579 VF Sb

  8. Using AC Motors in Robotics

    Directory of Open Access Journals (Sweden)

    Hosein Marzi

    2008-11-01

    Full Text Available It has been proven that fuzzy controllers are capable of controlling non-linear systems where it is cumbersome to develop conventional controllers based on mathematical modeling. This paper describes designing fuzzy controllers for an AC motor run mechanism. It also compares performance of two controllers designed based on Mamdani and Takagi-Sugeno with the conventional control scheme in a short track length, following a high disturbance. Fine and rapid control of AC motors have been a challenge and the main obstacle in gaining popularity in use of AC motors in robots actuators. This chapter reviews how use of intelligent control scheme can help to solve this problem.

  9. Research of 10kV Switchgear Partial Discharge Charged Detection Application based on Multi-dimensional Diagnostic Techniques%基于多维度诊断技术的10kV开关柜局放带电检测应用研究

    Institute of Scientific and Technical Information of China (English)

    陈俊; 王勇; 黄慧红; 刘俊翔

    2016-01-01

    With the advance of test pattern condition monitoring of 10 kV switchgear,the ultrasonic method,TEV and UHF method are applied to carry out the live testing of 10 kV switchgear.In this paper,by setting discharge source with different types of defects in the switchgear,a variety of diagnostic techniques including TEV,ultrasonic method are used to test discharge under the same test condition,aiming to determine the effectiveness of various diagnostic methods.Meanwhile, using the radio frequency electromagnetic scanning device,electromagnetic radiation around the switchgear with different types of discharge under different discharge voltage are measured,aiming to obtain clearer and more targeted atlas recognition results. Based on the test results,it is concluded that collaborative judgment using a variety of devices is an important protection of switchgear partial discharge detection precisely.%随着对10kV开关柜状态检测试验模式的不断推进,广州供电局分别应用了超声波、对地暂态过电压(TEV)、超高频等测试手段对10kV开关柜进行带电测试。通过在开关柜中设置不同类型缺陷的放电源,利用TEV法、超声法等多种诊断技术在同一试验条件下,对放电进行检测,从而判断各种诊断方法的有效性。同时,使用无线电磁波扫描装置,测量记录在不同放电类型、不同放电电压下,开关柜周围的电磁辐射状况,以期获得清晰且有针对性的图谱识别结果。基于试验结果可得,采用多种设备协同判断是准确进行开关柜局放检测的重要保障。

  10. Aislamiento acústico

    Directory of Open Access Journals (Sweden)

    Tobío, J. M.

    1970-07-01

    Full Text Available This is a very specific subject in the field of architectural acoustics, namely, insulation'. Emphasis is placed on the theoretical foundations of this phenomenon, and the most simple formula are developed to calculate easily the transmission losses of a material or the constructional insulating arrangements. The practical aspect of insulation can be considered by means of several graphs and charts, without the use of mathematics, and utilising common materials, that will not substantially increase the cost of the project. Finally this papers offers a critical discussion of building codes, and their reference to the acoustical insulation of dwellings, and data is included on the new regulations of the Madrid Municipality.Se trata un tema muy concreto de la Acústica Arquitectónica, el aislamiento, haciendo hincapié en los fundamentos teóricos del fenómeno y estableciendo las fórmulas más sencillas que permiten calcular fácilmente las pérdidas de transmisión de un material o disposición constructiva aislante. Varias gráficas y abacos permiten abordar, sin ningún tratamiento matemático, el problema práctico del aislamiento, aprovechando los materiales comunes y sin ocasionar gastos que graven sustancialmente el importe del proyecto. Por último, se hace un estudio crítico de las normas y su incidencia en los problemas del aislamiento de viviendas, incluyendo datos referentes a la nueva Ordenanza del Ayuntamiento de Madrid.

  11. Partial AC-coupling minigrids

    Energy Technology Data Exchange (ETDEWEB)

    Moix, Pierre-Olivier; Ruchet, Claude [Studer Innotec, Sion (Switzerland)

    2010-07-01

    Partial AC-coupling: - It is feasible to make AC-coupling of some compatible elements without V/f droops. Standard elements available on the market were tested. - Optimum design for efficiency is a share of the solar modules between DC-coupling with a solar charger and AC-coupling with a grid inverter according to the load profile. - Partial AC-coupling is better in term of robustness; it is more reliable to have at least a part of the solar production connected directly to DC, or even only DC coupling. The presented concepts are not only theoretical but were implemented and tested on real products available on the market. Many tests have been done to find out the limits and problems that can occur with the use of grid connected and stand alone inverter together. Many combinations were tested and it was found robust enough to be used in the field with the precautions mentioned about microcycling. (orig.)

  12. Total AC loss of YBCO coated conductor carrying AC transport current in AC transverse magnetic field with various orientations

    Energy Technology Data Exchange (ETDEWEB)

    Amemiya, Naoyuki [Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan); Jiang, Zhenan [Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan); Iijima, Yasuhiro [Materials Research Laboratory, Fujikura Ltd, 1-5-1 Kiba, Koto, Tokyo 135-8512 (Japan); Kakimoto, Kazuomi [Materials Research Laboratory, Fujikura Ltd, 1-5-1 Kiba, Koto, Tokyo 135-8512 (Japan); Saitoh, Takashi [Materials Research Laboratory, Fujikura Ltd, 1-5-1 Kiba, Koto, Tokyo 135-8512 (Japan)

    2004-08-01

    Using an electro-magnetic method, we measured the total AC loss of a YBCO coated conductor carrying an AC transport current in an AC transverse magnetic field with various orientations. We measured the magnetization loss (energy flow from the external magnetic field) and the transport loss (energy flow from the transport current circuit) independently during simultaneous application of an AC transverse magnetic field and AC transport current. Their sum gave us the total AC loss. The transport loss increases with increasing AC transverse magnetic field, and the magnetization loss increases with increasing AC transport current. The AC transverse magnetic field and the AC self magnetic field interact with each other at the conductor edges. This nonlinear interaction is a possible cause of the increase in AC loss. Due to the high aspect ratio of YBCO coated conductors, this increase in AC loss due to the interaction between the AC transverse and AC self magnetic fields is observed even when the transverse magnetic field is nearly parallel to the conductor wide-face. When the total AC losses for various transport currents and various field orientations are plotted against a transverse magnetic field component which is perpendicular to the conductor wide-face, the plots with different field angles but identical transport current all agree quite well with each other. The total AC loss is dominated by the self magnetic field and the perpendicular component of the transverse magnetic field, both of which mostly penetrate from the conductor edges.

  13. Distributed AC power flow method for AC and AC-DC hybrid ...

    African Journals Online (AJOL)

    DR OKE

    Present MGs incorporate AC and DC sources and loads along with storage and power ... Keywords: Microgrid (MG), Distributed Energy Resources (DER), Particle ... But in case of renewable based MGs, where small and intermittent sources ...

  14. 低频唤醒在电厂高压开关柜触头温度监测中的应用%Application of Low Frequency Wake-up in High Voltage Switchgear Contact Temperature Monitoring for Power Plants

    Institute of Scientific and Technical Information of China (English)

    周晓莉

    2014-01-01

    针对无线式电厂高压开关柜触头温度监测中无线采集模块供电不稳和系统组网问题,提出了一种无线采集模块采用高方式间歇工作的方法,降低了功耗,解决了无线发送冲突的问题。给出了系统框图,阐述了工作原理,介绍了低频唤醒方式的具体实现方法。%This paper puts forward a method of wireless picking module by batch working according to low frequency wake-up. It solves the problem of instable current supply and system network of the wireless picking module in the system of high voltage switchgear contact temperature monitoring for power plants. The method reduces the power consumption and solves the problem of the conflict of wireless transmission. It provides the system block diagram of the module and represents its working principle. At last, it offers the detailed method of the low frequency wake-up.

  15. Hopping models and ac universality

    DEFF Research Database (Denmark)

    Dyre, Jeppe; Schrøder, Thomas

    2002-01-01

    Some general relations for hopping models are established. We proceed to discuss the universality of the ac conductivity which arises in the extreme disorder limit of the random barrier model. It is shown that the relevant dimension entering into the diffusion cluster approximation (DCA) is the h......) is the harmonic (fracton) dimension of the diffusion cluster. The temperature scaling of the dimensionless frequency entering into the DCA is discussed. Finally, some open problems regarding ac universality are listed.......Some general relations for hopping models are established. We proceed to discuss the universality of the ac conductivity which arises in the extreme disorder limit of the random barrier model. It is shown that the relevant dimension entering into the diffusion cluster approximation (DCA...

  16. Speed Control of DC Motor using AC/AC/DC Converter Based on Intelligent Techniques

    Directory of Open Access Journals (Sweden)

    Rakan Kh Antar

    2013-05-01

    Full Text Available    This paper describes the application of ac/ac/dc and ac/dc converters to control the speed of a separately excited DC motor. Artificial neural network and PI controller are trained to select the desired values of firing angles for triggering thyristors of the ac/ac/dc and ac/dc bridge converters in order to control the speed of the dc motor at a desired value with constant and different load torques in order to obtain the best speed response. Simulation results show that the rising time for ac/dc and ac/ac/dc converters at 250rpm are reduced about 79% and 89% respectively, while delay time it reduced about 69% and 64% respectively. Therefore, speed response of the dc motor is more efficient for closed loop system compared with open loop also the response of ac/ac/dc converter is better than ac/dc converter.

  17. AC410 Unit 9 Assignment

    OpenAIRE

    Laynebaril1

    2017-01-01

     AC410 Unit 9 Assignment Click Link Below To Buy: http://hwcampus.com/shop/ac410-unit-9-assignment/   18–29. The CPA firm of Carson & Boggs LLP is performing an internal control audit in accordance with PCAOB Standard No. 5. The partner in charge of the engagement has asked you to explain the process of determining which controls to test. Describe the process, presenting each of the links in this process and a short summary of how the auditors approach each of them. v ...

  18. Electrothermal ac electro-osmosis

    Science.gov (United States)

    Gagnon, Zachary R.; Chang, Hsueh-Chia

    2009-01-01

    Two ac polarization mechanisms, charge accumulation due to electrode double layer charging and bulk permittivity/conductivity gradients generated by Joule heating, are combined in the double layer by introducing zwitterions to produce a new ac electrokinetic pump with the largest velocity (>1 mm/s) and flow penetration depth (100 μm) reported for low-conductivity fluids. The large fluid velocity is due to a quartic scaling with respect to voltage, as is true of electrothermal flow, but exhibits a clear maximum at a frequency corresponding to the electrode double layer inverse RC time.

  19. Nuclear structure of $^{231}$Ac

    CERN Document Server

    Boutami, R; Mach, H; Kurcewicz, W; Fraile, L M; Gulda, K; Aas, A J; García-Raffi, L M; Løvhøiden, G; Martínez, T; Rubio, B; Taín, J L; Tengblad, O

    2008-01-01

    The low-energy structure of 231Ac has been investigated by means of gamma ray spectroscopy following the beta-decay of 231Ra. Multipolarities of 28 transitions have been established by measuring conversion electrons with a mini-orange electron spectrometer. The decay scheme of 231Ra --> 231Ac has been constructed for the first time. The Advanced Time Delayed beta-gamma-gamma(t) method has been used to measure the half-lives of five levels. The moderately fast B(E1) transition rates derived suggest that the octupole effects, albeit weak, are still present in this exotic nucleus.

  20. AcEST: DK963222 [AcEST

    Lifescience Database Archive (English)

    Full Text Available sp|P81919|OR46A_DROME Odorant receptor 46a, isoform A OS=Drosoph... 32 2.8 sp|Q5MJ68|SPDYC_HUMAN Speed...FCFKA 181 CS +T + AV S L + +YV + AC Q FI C+ A Sbjct: 262 CSVLVLTANFYAIAVLSDERLELFKYVTYQACMLIQIFILCYYA 305 >sp|Q5MJ68|SPDYC_HUMAN Spee

  1. AcEST: DK953266 [AcEST

    Lifescience Database Archive (English)

    Full Text Available 34 0.49 sp|A5VSF3|ACSA_BRUO2 Acetyl-coenzyme A synthetase OS=Brucella ov... 34 0.49 sp|Q8YJ48|ACSA_BRUME Ac... K++ + NK L+ R G WG GR++ Sbjct: 180 FVITADEGVRGGKPVALKENTDTAIDIAAKQYVMVNKVLVVRRTGGKVSWGRGRDL 235 >sp|A5VSF3|ACSA_BRUO2

  2. AcEST: BP918420 [AcEST

    Lifescience Database Archive (English)

    Full Text Available D 180 >sp|A8AC98|APGM_IGNH4 2,3-bisphosphoglycerate-independent phosphoglycerate mutase OS=Ignicoccus hosp...italis (strain KIN4/I / DSM 18386 / JCM 14125) GN=apgM PE=3 SV=1 Length = 416 Score

  3. AcEST: BP921446 [AcEST

    Lifescience Database Archive (English)

    Full Text Available 34 2e-30 tr|A4VIU1|A4VIU1_PSEU5 Putative uncharacterized protein OS=Pseud... 129 1e-28 tr|Q11HF6|Q11HF6_MESSB...EHTHLMLDSKAGWVEPHIQAGDRCFAEYPDESLAQWHERLGL 159 >tr|Q11HF6|Q11HF6_MESSB Glutathione-dependent formaldehyde-ac

  4. AcEST: BP917259 [AcEST

    Lifescience Database Archive (English)

    Full Text Available Q96AC6|KIFC2_HUMAN Kinesin-like protein KIFC2 OS=Homo sapiens... 30 9.0 sp|O88737|BSN_MOUSE Protein bassoon ... WGQPG AAGS + PG Sbjct: 748 SSSPTEWVKWSWGQPG-------AAGSRAPPG 772 >sp|O88737|BSN_MOUSE Protein bassoon

  5. AcEST: DK947455 [AcEST

    Lifescience Database Archive (English)

    Full Text Available tative uncharacterized protein OS=Picea... 246 9e-64 tr|A8QIH7|A8QIH7_MORAL Chlor...DPTARSDNGSCEYEFKE 479 >tr|A8QIH7|A8QIH7_MORAL Chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase ac

  6. AcEST: DK943932 [AcEST

    Lifescience Database Archive (English)

    Full Text Available rella paten... 145 2e-33 tr|B6T2L2|B6T2L2_MAIZE Sedoheptulose-1,7-bisphosphatase ...EAL++SHVCK+AC Sbjct: 67 ATACVNTFGDEQLAVDMLADKLLFEALRHSHVCKYAC 103 >tr|B6T2L2|B6T2L2_MAIZE Sedoheptulose-1,7-

  7. AcEST: DK961189 [AcEST

    Lifescience Database Archive (English)

    Full Text Available OS=A... 127 7e-29 sp|Q94B08|GCP1_ARATH Germination-specific cysteine protease 1 OS... 125 2e-28 sp|P00785|AC...IRNSWGLNWGDSGYVKLQRNIDDPFGKCGIAMMPSYP 347 >sp|Q94B08|GCP1_ARATH Germination-specific cysteine protease 1 OS=

  8. ACS from development to operations

    Science.gov (United States)

    Caproni, Alessandro; Colomer, Pau; Jeram, Bogdan; Sommer, Heiko; Chiozzi, Gianluca; Mañas, Miguel M.

    2016-08-01

    The ALMA Common Software (ACS), provides the infrastructure of the distributed software system of ALMA and other projects. ACS, built on top of CORBA and Data Distribution Service (DDS) middleware, is based on a Component- Container paradigm and hides the complexity of the middleware allowing the developer to focus on domain specific issues. The transition of the ALMA observatory from construction to operations brings with it that ACS effort focuses primarily on scalability, stability and robustness rather than on new features. The transition came together with a shorter release cycle and a more extensive testing. For scalability, the most problematic area has been the CORBA notification service, used to implement the publisher subscriber pattern because of the asynchronous nature of the paradigm: a lot of effort has been spent to improve its stability and recovery from run time errors. The original bulk data mechanism, implemented using the CORBA Audio/Video Streaming Service, showed its limitations and has been replaced with a more performant and scalable DDS implementation. Operational needs showed soon the difference between releases cycles for Online software (i.e. used during observations) and Offline software, which requires much more frequent releases. This paper attempts to describe the impact the transition from construction to operations had on ACS, the solution adopted so far and a look into future evolution.

  9. 基于偏最小二乘法的3/2接线方式下开关回路电阻在线评估方法%On-line Evaluation of Switchgear Circuit Resistance Under 3/2 Connection Mode Based on Partial Least Squares Method

    Institute of Scientific and Technical Information of China (English)

    侯洋; 吉晓筱; 卜京; 夏方涛

    2016-01-01

    Switchgear circuit resistance is one of the most important parameters to evaluate the status of switch equipment. Aiming at the online evaluation problem of switchgear circuit resistance under 3/2 connection mode, a kind of online calculation method based on partial least squares is proposed. The mathematical model of switchgear circuit resistance is established according to the data of current flowing through switch equipment and Kirchhoff’s law. To reduce the error caused by the high linear correlation of current condition at different time, partial least squares method is used to calculate the switchgear circuit resistance. Lastly,using a 500 kV substation which uses 3/2 connection mode as an example to do simulation calculation. The result shows that partial least squares method can reduce the error caused by the high linear correlation of current condition obviously. Compared with least squares method, partial least squares method is more accurate.%开关回路电阻是评价开关设备状态的重要参数之一,针对3/2接线方式变电站开关回路电阻在线评估问题,提出一种基于偏最小二乘法的在线计算方法。根据变电站开关电流数据和基尔霍夫定律,建立开关回路电阻的数学模型。为减小不同时刻电流工况线性相关性带来的误差,采用偏最小二乘法求解开关回路电阻。最后,以采用3/2接线方式的某500 kV变电站为例,进行仿真计算。结果表明,采用偏最小二乘法能显著减小电流工况线性相关性带来的误差,相比于最小二乘法,精度更高。

  10. AcEST: DK943965 [AcEST

    Lifescience Database Archive (English)

    Full Text Available FKBP-type OS=Cya... 55 2e-06 tr|B8EIG1|B8EIG1_METSI Peptidylprolyl isomerase FKBP-type OS=Met... 53 9e-06 t... type OS=Ac... 51 4e-05 tr|B8I9L2|B8I9L2_METNO Peptidylprolyl isomerase FKBP-type OS=Met.

  11. Efficient Found of Insulation Defect in Alternating Current Withstand Voltage Test of Gas Insulated Switchgear%GIS交流耐压试验中绝缘缺陷的高效发现

    Institute of Scientific and Technical Information of China (English)

    严鹏志; 黄烜城; 刘全; 赵凯强

    2015-01-01

    Introduction was made to the corresponding standard of alternating current withstand voltage test of gas insulated switchgear (GIS) type in state grid corporation of China. This paper compared the differences of two kinds of auxiliary detection methods, ultrahigh frequency (UHF) and ultrasonic (AE) and the detection effect of similar signal sources. Aiming at the two breakdown events of withstand voltage tests, this paper analyzed the process of insulation defect discovery in test. The results show that the seriously executive standard plays an important role in finding the hidden dangers of equipment insulation for alternating current withstand voltage tests. The comprehensive application of UHF and AE detection methods could compensate each other's advantages, suppressing the impacts of interference factors on identification signals.%介绍了国家电网公司对气体绝缘开关设备(GIS)类设备交流耐压的相关标准,比较了两种辅助检测方法特高频法(UHF)和超声波法(AE)的差异及对同类信号源的检测效果。针对两起耐压试验击穿事件,对试验中绝缘缺陷发现的过程进行分析,结果表明从严执行标准对交接耐压试验中高效发现设备绝缘隐患具有重要作用,综合运用UHF和AE检测法,实现两者的优势互补,可排除干扰因素对判读信号的影响。

  12. AC dynamometer; Koryu dinamo meter

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-01-10

    Fuji Electric Co., Ltd., developed an AC dynamometer for testing automobiles, and the product was delivered to Hokkaido Automotive Engineering College via Safety Automobile Company. The device is used for testing 1,300cc-class automobiles. It is similar to the conventional type in that its force of reaction to an imposed load is measured by load cells. It is a variable speed motor driven by an inverter (FRENIC5000VG5), whose specifications and features are mentioned below. It is a totally-enclosed self-cooled oscillating AC dynamometer that outputs 75kW, revolves at 1500/2868rpm, and operates for 30min. Since it is rated for a short time operation, the external fan is dispensed with, and this reduces noise. A number of parts for the standard type (R90 series) are utilized for reduction in the cost, and the time required for its delivery was short. (NEDO)

  13. Performance of AC/graphite capacitors at high weight ratios of AC/graphite

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongyu [IM and T Ltd., Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan); Yoshio, Masaki [Advanced Research Center, Department of Applied Chemistry, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan)

    2008-03-01

    The effect of negative to positive electrode materials' weight ratio on the electrochemical performance of both activated carbon (AC)/AC and AC/graphite capacitors has been investigated, especially in the terms of capacity and cycle-ability. The limited capacity charge mode has been proposed to improve the cycle performance of AC/graphite capacitors at high weight ratios of AC/graphite. (author)

  14. AcEST: DK943968 [AcEST

    Lifescience Database Archive (English)

    Full Text Available = +2 Query: 71 SSIRDLDNSRPRAIACSDNSGICVAVAYNHLANM------AVATFRDKPSVHQAGS---M 223 SS+ S P AC+ N+ VA HL+N+ A+ F...ives = 24/56 (42%) Frame = +2 Query: 107 AIACSDNSGICVAVAYNHLANMAVATFRDKPSVHQAGSMN...es = 83/195 (42%), Gaps = 1/195 (0%) Frame = +2 Query: 32 VLTACSSGVYFWDSSIRDLDNSRPRAIACSDNSGICVAVAYNHLANMAVA.../188 (41%), Gaps = 2/188 (1%) Frame = +2 Query: 32 VLTACSSGVYFWDSSIRDLDNSRPRAIACSDNSGICVAVAYN-HLANMAVATFRDKP... VLTACSSGVYFWDSSIRDLDNSRPRAIACSDNSGICVAVAYN-HLANMAVATFRDKPSVH 208 V++A S G WD D +RP + +N G+C+++A N +++ VA+FR

  15. AcEST: DK954735 [AcEST

    Lifescience Database Archive (English)

    Full Text Available AC ■■Homology search results ■■ - Swiss-Prot (release 56.9) Link to BlastX Result : Swiss-Prot sp_hit_id Q7TMD5 Definition sp|Q7TMD5...ng significant alignments: (bits) Value sp|Q7TMD5|ZC3HE_RAT Zinc finger CCCH domain-containing protein 1... ...tein pstB ... 30 5.8 sp|Q2S081|PSTB_SALRD Phosphate import ATP-binding protein pstB O... 30 7.6 >sp|Q7TMD5

  16. Effect of the magnetic material on AC losses in HTS conductors in AC magnetic field carrying AC transport current

    Science.gov (United States)

    Wan, Xing-Xing; Huang, Chen-Guang; Yong, Hua-Dong; Zhou, You-He

    2015-11-01

    This paper presents an investigation on the AC losses in several typical superconducting composite conductors using the H-formulation model. A single superconducting strip with ferromagnetic substrate or cores and a stack of coated conductors with ferromagnetic substrates are studied. We consider all the coated conductors carrying AC transport currents and simultaneously exposed to perpendicular AC magnetic fields. The influences of the amplitude, frequency, phase difference and ferromagnetic materials on the AC losses are investigated. The results show that the magnetization losses of single strip and stacked strips have similar characteristics. The ferromagnetic substrate can increase the magnetization loss at low magnetic field, and decrease the loss at high magnetic field. The ferromagnetic substrate can obviously increase the transport loss in stacked strips. The trends of total AC losses of single strip and stacked strips are similar when they are carrying current or exposed to a perpendicular magnetic field. The effect of the frequency on the total AC losses of single strip is related to the amplitude of magnetic field. The AC losses decrease with increasing frequency in low magnetic field region while increase in high magnetic field region. As the phase difference changes, there is a periodic variation for the AC losses. Moreover, when the strip is under only the transport current and magnetic field, the ferromagnetic cores will increase the AC losses for large transport current or field.

  17. Universality of ac conduction in disordered solids

    DEFF Research Database (Denmark)

    Dyre, Jeppe; Schrøder, Thomas

    2000-01-01

    The striking similarity of ac conduction in quite different disordered solids is discussed in terms of experimental results, modeling, and computer simulations. After giving an overview of experiment, a macroscopic and a microscopic model are reviewed. For both models the normalized ac conductivity...... as a function of a suitably scaled frequency becomes independent of details of the disorder in the extreme disorder limit, i.e., when the local randomly varying mobilities cover many orders of magnitude. The two universal ac conductivities are similar, but not identical; both are examples of unusual non......-power-law universalities. It is argued that ac universality reflects an underlying percolation determining dc as well as ac conductivity in the extreme disorder limit. Three analytical approximations to the universal ac conductivities are presented and compared to computer simulations. Finally, model predictions...

  18. Control of grid interactive AC microgrids

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Guerrero, Josep M.; Chen, Zhe

    2010-01-01

    and reliability, becomes an attractive candidate for the configuration of future electrical power system. This paper gives a brief review of grid interactive ac microgrid configurations. Control methods for power electronics interfaced DER units in grid interactive ac microgrids are discussed. In addition......, microgrid controls and power management strategies are presented. Future trends of microgrid are discussed pointing out how this concept can be a key to achieve a more intelligent and flexible AC grid....

  19. RHIC spin flipper AC dipole controller

    Energy Technology Data Exchange (ETDEWEB)

    Oddo, P.; Bai, M.; Dawson, C.; Gassner, D.; Harvey, M.; Hayes, T.; Mernick, K.; Minty, M.; Roser, T.; Severino, F.; Smith, K.

    2011-03-28

    The RHIC Spin Flipper's five high-Q AC dipoles which are driven by a swept frequency waveform require precise control of phase and amplitude during the sweep. This control is achieved using FPGA based feedback controllers. Multiple feedback loops are used to and dynamically tune the magnets. The current implementation and results will be presented. Work on a new spin flipper for RHIC (Relativistic Heavy Ion Collider) incorporating multiple dynamically tuned high-Q AC-dipoles has been developed for RHIC spin-physics experiments. A spin flipper is needed to cancel systematic errors by reversing the spin direction of the two colliding beams multiple times during a store. The spin flipper system consists of four DC-dipole magnets (spin rotators) and five AC-dipole magnets. Multiple AC-dipoles are needed to localize the driven coherent betatron oscillation inside the spin flipper. Operationally the AC-dipoles form two swept frequency bumps that minimize the effect of the AC-dipole dipoles outside of the spin flipper. Both AC bumps operate at the same frequency, but are phase shifted from each other. The AC-dipoles therefore require precise control over amplitude and phase making the implementation of the AC-dipole controller the central challenge.

  20. AcEST: DK959751 [AcEST

    Lifescience Database Archive (English)

    Full Text Available .. 86 1e-16 sp|A0FGR8|ESYT2_HUMAN Extended synaptotagmin-2 OS=Homo sapiens G... 72 3e-12 sp|Q6PFQ7|RASL2_MOU...SE Ras GTPase-activating protein 4 OS=Mus mus... 72 4e-12 sp|Q3TZZ7|ESYT2_MOUSE Extended...ivating-like protein 1 OS=Mus mu... 65 3e-10 sp|Q5M7N9|ESYT3_XENTR Extended synaptotagmin-3 OS=Xenopus tropi... 1 OS=Homo s... 61 6e-09 sp|Q8L7A4|AGD11_ARATH Probable ADP-ribosylation factor GTPase-ac... 61 6e-09 sp|Q7ZWU7|EST2B_XENLA Extended... synaptotagmin-2-B OS=Xenopus laev... 60 1e-08 sp|Q5FWL4|EST2A_XENLA Extended

  1. AcEST: BP920842 [AcEST

    Lifescience Database Archive (English)

    Full Text Available ta... 59 6e-09 sp|Q3TZZ7|ESYT2_MOUSE Extended synaptotagmin-2 OS=Mus musculus G... 59 7e-09 sp|Q9ZT47|PP16A_...CUCMA 16 kDa phloem protein 1 OS=Cucurbita maxim... 57 2e-08 sp|A0FGR8|ESYT2_HUMAN Extended synaptotagmin-2 ... domain-conta... 56 6e-08 sp|Q8L7A4|AGD11_ARATH Probable ADP-ribosylation factor GTPase-ac... 55 8e-08 sp|A0FGR9|ESYT3_HUMAN Extended... synaptotagmin-3 OS=Homo sapiens G... 55 1e-07 sp|Q5DTI8|ESYT3_MOUSE Extended synap...totagmin-3 OS=Mus musculus G... 54 2e-07 sp|Q5M7N9|ESYT3_XENTR Extended synaptota

  2. AcEST: DK956298 [AcEST

    Lifescience Database Archive (English)

    Full Text Available AIZE Glutamate dehydrogenase OS=Zea mays GN=GDH1... 370 e-102 sp|Q43314|DHE1_ARATH Glutamate dehydrogenase 1...HGK 202 >sp|P93541|DHE3_SOLLC Glutamate dehydrogenase OS=Solanum lycopersicum GN=GDH1 PE=2 SV=1 Length = 412...RG ++A EALL ++G+ Sbjct: 181 RDAATGRGALFATEALLNEHGK 202 >sp|Q43260|DHE3_MAIZE Glutamate dehydrogenase OS=Zea mays GN=GDH1...ATH Glutamate dehydrogenase 1 OS=Arabidopsis thaliana GN=GDH1 PE=1 SV=1 Length = 411 Score = 369 bits (946),...AC Glutamate dehydrogenase OS=Nicotiana taba... 376 e-103 tr|A7YVW3|A7YVW3_ACTCH GDH1 OS=Actinidia chinensis GN=GDH1

  3. Investigation of the Coupling Paths of a Galvanically Isolated AC/AC Converter

    NARCIS (Netherlands)

    Roc'h, Anne; Zhao, Dongsheng; Leferink, Frank; Polinder, Henk; Ferreira, Braham

    2007-01-01

    A galvanically isolated three-phase AC/AC converter with a high-frequency AC-link has been analyzed from an EMC point of view. This is a special configuration because of a large number of switches, a high frequency transformer, and a fourwire output. The essential coupling paths are identified. Corr

  4. AC polarographic determination of cloxacillin.

    Science.gov (United States)

    Núñez-Vergara, L J; Silva, M M; Squella, J A

    1982-11-01

    Hydrolysis of cloxacillin at pH 4.0 yields an electroactive product which can be determined by polarography. Depending on the concentration of cloxacillin, one of 2 peaks was obtained: The potential ac peaks for a 4.36 mM cloxacillin solution were peak I, -0.23 V and peak II, -0.13 V. For analytical purposes, the first peak was used. A linear relationship was established for levels of cloxacillin between 2.2 X 10(-5) and 2.2 X 10(-3)M. Average recovery was 98.8% (SD 1.8), indicating satisfactory accuracy for the method. Individual capsule and composite assays as well as interference tests are described.

  5. AC-tabsmodeller for superledende kabelledere

    DEFF Research Database (Denmark)

    Østergaard, Jacob; Holm (fratrådt), Jesper; Understrup (fratrådt), Henriette

    1996-01-01

    I denne rapport opstilles tre modeller for beregning af AC-tab (vekselstrømstab) i superledende kabelledere. Beregning af tabenes størrelse er væsentlig i forbindelse med vurdering af superlederteknologiens anvendelighed til AC-applikationer. Viden om tabenes natur giver desuden et vigtigt...

  6. AcEST: BP916793 [AcEST

    Lifescience Database Archive (English)

    Full Text Available SC complexes subunit ssr2 OS=S... 66 6e-14 sp|Q9XI07|SWI3C_ARATH SWI/SNF complex subunit SWI3C OS=Arabidops...... 65 1e-12 sp|Q8VY05|SWI3D_ARATH SWI/SNF complex subunit SWI3D OS=Arabidops... 66 2e-12 sp|P97496|SMRC1_MOU...2|SWI3B_ARATH SWI/SNF complex subunit SWI3B OS=Arabidops... 59 9e-09 sp|Q8W475|SWI3A_ARATH SWI/SNF complex s...ional adapter ADA2 OS=Oryza sati... 47 3e-05 sp|Q9ATB4|TAD2B_ARATH Transcriptional adapter ADA2b OS=Arabidops...... 45 2e-04 sp|Q9SFD5|TAD2A_ARATH Transcriptional adapter ADA2a OS=Arabidops... 44 3e-04 sp|Q5ZJF3|TAD2A_C

  7. Memory effect in ac plasma displays

    Science.gov (United States)

    Szlenk, K.; Obuchowicz, E.

    1993-10-01

    The bistable or `memory' mode of operation of an ac plasma display panel is presented. The difference between dc and ac plasma panel operation from the point of view of memory function is discussed. The graphic ac plasma display with thin film Cr-Cu-Cr electrodes was developed in OBREP and its basic parameters are described. It consists of 36 X 59 picture elements, its outer dimensions are: 76 X 52 mm2 and the screen size is: 49 X 30 mm2. The different dielectric glass materials were applied as dielectric layers and the influence of the properties of these materials on display parameters and memory function was investigated.

  8. Switchgear installations for extremely high voltages

    Energy Technology Data Exchange (ETDEWEB)

    Muller, M.; Stepinski, B.

    1964-01-01

    The methods by which 750-kV installations can be economically constructed are described. Besides the choice of phase distances and conductors, the possible layouts and circuitry are dealt with and illustrated by results obtained from the basic studies of 750-kV equipment. In conclusion, a comparison of costs is made, both for the individual components and for the overall financial outlay for the arrangements considered; the total and itemized costs of compounds for voltages of 245 to 750 kV according to the present state of the art are also discussed.

  9. DC-Modulated PFC Buck-Type AC/AC Converter for Light Dimming

    Institute of Scientific and Technical Information of China (English)

    罗方林; 叶虹

    2007-01-01

    Dimmers are very widely applied in theatres, cinemas, dancing-parties, auditoriums and signal systems. They are usually supplied by single-stage AC/AC converters in the past with voltage regulation technique with the disadvantages of high total harmonic distortion, low power factor and poor power transfer efficiency. This paper introduces a novel method-DC-modulation that implements DC/DC conversion technology into AC/AC converters. The DC-modulated single-stage PFC AC/AC converters effectively improved the power factor up to 0.999 and the power transfer efficiency up to 97.8 %. The experimental results verified our design and calculation. This technique will be widely used in light dimming and other industrial applications.

  10. Cooperative Frequency Control for Autonomous AC Microgrids

    DEFF Research Database (Denmark)

    Shafiee, Qobad; Quintero, Juan Carlos Vasquez; Guerrero, Josep M.

    2015-01-01

    Distributed secondary control strategies have been recently studied for frequency regulation in droop-based AC Microgrids. Unlike centralized secondary control, the distributed one might fail to provide frequency synchronization and proportional active power sharing simultaneously, due to having...... not require measuring the system frequency as compared to the other presented methods. An ac Microgrid with four sources is used to verify the performance of the proposed control methodology....

  11. Guiding Principles in Selecting AC To DC Converters For Power Factor Corrections in AC Transmission System

    Directory of Open Access Journals (Sweden)

    Ibekwe B.E

    2014-10-01

    Full Text Available The ac to dc converters’ power factors correction in ac transmission system were investigated. The studies include: phase-controlled converter; pulse width modulated (PWM converter and ac input current shaped converter. Using Fourier series, power factors of these converters were calculated and simulated using MATLAB. The resulting curves are displayed in the hard copies for practical guides in the choice of converters; and comparatively, current shaped type is the best.

  12. The Effect of the Feedback Controller on Superconducting Tokamak AC Losses + AC-CRPP user manual

    Energy Technology Data Exchange (ETDEWEB)

    Schaerz, B.; Bruzzone, P.; Favez, J.Y.; Lister, J.B.; Zapretilina, E

    2001-11-01

    Superconducting coils in a Tokamak are subject to AC losses when the field transverse to the coil current varies. A simple model to evaluate the AC losses has been derived and benchmarked against a complete model used in the ITER design procedure. The influence of the feedback control strategy on the AC losses is examined using this model. An improved controller is proposed, based on this study. (author)

  13. 马士基将重组AC-2和AC-3航线

    Institute of Scientific and Technical Information of China (English)

    燕翔(整理)

    2014-01-01

    马士基航运将重组其远东-墨西哥-中美洲-南美洲西海岸航线“AC-2”线和“AC-3”线。“AC-2”线将延伸至华北和韩国,同时不再挂靠华南,在亚洲,该航线将加挂青岛和釜山,

  14. imulation Results of Single Stage AC- AC Converter for Induction Heating

    Directory of Open Access Journals (Sweden)

    S. ARUMUGAM

    2010-12-01

    Full Text Available This paper presents simulation of single stage Induction heating system with series Load Resonance. Low frequency AC is converted in to High Frequency Ac using newly developed ZVS-PWM high frequency inverter. This High Frequency is used for Induction Heating .Single stage AC-AC converter system is modeled and simulated using Matlab Simulink. The simulation results of ZVS-PWM high frequency system are presented. The effectiveness of this UFAC-to-HFAC direct power frequency converter using IGBTs for consumer high-frequency IH appliances is evaluated and proved on the basis of simulation results.

  15. 78 FR 39345 - ACS Wireless, Inc.; Notice of Application

    Science.gov (United States)

    2013-07-01

    ... No. 812-14066] ACS Wireless, Inc.; Notice of Application AGENCY: Securities and Exchange Commission... (``Act''). Summary of Application: ACS Wireless, Inc. (``ACS Wireless'') seeks an order under section 3(b..., reinvesting, owning, holding or trading in securities. ACS Wireless is primarily engaged in providing...

  16. 21 CFR 886.1850 - AC-powered slitlamp biomicroscope.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered slitlamp biomicroscope. 886.1850... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1850 AC-powered slitlamp biomicroscope. (a) Identification. An AC-powered slitlamp biomicroscope is an AC-powered device that is...

  17. 21 CFR 886.4440 - AC-powered magnet.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  18. 21 CFR 888.1240 - AC-powered dynamometer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered dynamometer. 888.1240 Section 888.1240...) MEDICAL DEVICES ORTHOPEDIC DEVICES Diagnostic Devices § 888.1240 AC-powered dynamometer. (a) Identification. An AC-powered dynamometer is an AC-powered device intended for medical purposes to...

  19. 21 CFR 886.1630 - AC-powered photostimulator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered photostimulator. 886.1630 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1630 AC-powered photostimulator. (a) Identification. An AC-powered photostimulator is an AC-powered device intended to provide light stimulus...

  20. AC Electrokinetics of Physiological Fluids for Biomedical Applications.

    Science.gov (United States)

    Lu, Yi; Liu, Tingting; Lamanda, Ariana C; Sin, Mandy L Y; Gau, Vincent; Liao, Joseph C; Wong, Pak Kin

    2015-12-01

    Alternating current (AC) electrokinetics is a collection of processes for manipulating bulk fluid mass and embedded objects with AC electric fields. The ability of AC electrokinetics to implement the major microfluidic operations, such as pumping, mixing, concentration, and separation, makes it possible to develop integrated systems for clinical diagnostics in nontraditional health care settings. The high conductivity of physiological fluids presents new challenges and opportunities for AC electrokinetics-based diagnostic systems. In this review, AC electrokinetic phenomena in conductive physiological fluids are described followed by a review of the basic microfluidic operations and the recent biomedical applications of AC electrokinetics. The future prospects of AC electrokinetics for clinical diagnostics are presented.

  1. The Sloan Lens ACS Survey. V. The full ACS strong-lens sample

    NARCIS (Netherlands)

    Bolton, Adam S.; Burles, Scott; Koopmans, Leon V. E.; Treu, Tommaso; Gavazzi, Raphael; Moustakas, Leonidas A.; Wayth, Randall; Schlegel, David J.

    2008-01-01

    We present the definitive data for the full sample of 131 strong gravitational lens candidates observed with the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope by the Sloan Lens ACS (SLACS) Survey. All targets were selected for higher redshift emission lines and lower redshift

  2. The Sloan Lens ACS Survey. V. The full ACS strong-lens sample

    NARCIS (Netherlands)

    Bolton, Adam S.; Burles, Scott; Koopmans, Leon V. E.; Treu, Tommaso; Gavazzi, Raphael; Moustakas, Leonidas A.; Wayth, Randall; Schlegel, David J.

    2008-01-01

    We present the definitive data for the full sample of 131 strong gravitational lens candidates observed with the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope by the Sloan Lens ACS (SLACS) Survey. All targets were selected for higher redshift emission lines and lower redshift c

  3. Approaches to building single-stage AC/AC conversion switch-mode audio power amplifiers

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2004-01-01

    This paper discusses the possible topologies and promising approaches towards direct single-phase AC-AC conversion of the mains voltage for audio applications. When compared to standard Class-D switching audio power amplifiers with a separate power supply, it is expected that direct conversion...

  4. Cyclotron and linac production of Ac-225.

    Science.gov (United States)

    Melville, Graeme; Allen, Barry J

    2009-04-01

    Radium needles that were once implanted into tumours as a cancer treatment are now obsolete and constitute a radioactive waste problem, as their half-life is 1600 years. The reduction of radium by photonuclear transmutation by bombarding Ra-226 with high-energy photons from a medical linear accelerator (linac) has been investigated. A linac dose of 2800 Gy produced about 2.4 MBq (64 microCi) of Ra-225, which decays to Ac-225 and can then be used for 'Targeted Alpha Therapy' (TAT) of cancer. This result, while consistent with theoretical calculations, is far too low to be of practical use unless much larger quantities of radium are irradiated. The increasing application of Ac-225 for cancer therapy indicates the potential need for its increased production and availability. This paper investigates the possibility of producing of Ac-225 in commercial quantities, which could potentially reduce obsolete radioactive material and displace the need for expensive importation of Ac-225 from the USA and Russia in the years ahead. Scaled up production of Ac-225 could theoretically be achieved by the use of a high current cyclotron or linac. Production specifications are determined for a linac in terms of current, pulse length and frequency, as well as an examination of other factors such as radiation issues and radionuclei separation. Yields are compared with those calculated for the Australian National Cyclotron in Sydney.

  5. AC/DC and DC/AC Converty Circuits in Power Supply Equipment%电源设备中AC/DC和DC/AC变换电路

    Institute of Scientific and Technical Information of China (English)

    杨碧石

    2001-01-01

    电源设备中根据电路变换功能来看,可分为四种类型:AC/DC、DC/AC、DC/DC、AC/AC,本文对AC/DC、DC/AC这两种变换的工作原理进行分析阐述并讨论每种电路的应用领域.

  6. AC susceptibilities of grain-textured superconductors

    Science.gov (United States)

    Sakamoto, N.; Fukuda, Y.; Koga, M.; Akune, T.; Khan, H. R.; Lüders, K.

    2008-09-01

    In-phase χ n‧ and out-phase χ n″ components of nth harmonics of AC susceptibility with measuring parameters of a DC magnetic field Bdc, an amplitude Ba and a frequency f of the superimposed AC magnetic fields give substantial information of the superconducting properties. In low- Tc metallic superconductors, χ1‧ shows smooth transition and χ1″ does single peak. High- Tc oxide superconductors with anisotropic and grain-textured structures show deformed complex characteristics. Double peaks in χ1″ and shoulders in χ1‧ appear in AC susceptibility of Hg-1223 superconductors. Instead of simple Bean model, a grained model, where the superconducting grains are immersed in weak superconducting matrix, are proposed. The susceptibilities numerically analyzed using the model show varied and deformed curves and are successfully compared with the measured results.

  7. Nuclear structure of {sup 231}Ac

    Energy Technology Data Exchange (ETDEWEB)

    Boutami, R. [Instituto de Estructura de la Materia, CSIC, Serrano 113 bis, E-28006 Madrid (Spain); Borge, M.J.G. [Instituto de Estructura de la Materia, CSIC, Serrano 113 bis, E-28006 Madrid (Spain)], E-mail: borge@iem.cfmac.csic.es; Mach, H. [Department of Radiation Sciences, ISV, Uppsala University, SE-751 21 Uppsala (Sweden); Kurcewicz, W. [Department of Physics, University of Warsaw, Pl-00 681 Warsaw (Poland); Fraile, L.M. [Departamento Fisica Atomica, Molecular y Nuclear, Facultad CC. Fisicas, Universidad Complutense, E-28040 Madrid (Spain); ISOLDE, PH Department, CERN, CH-1211 Geneva 23 (Switzerland); Gulda, K. [Department of Physics, University of Warsaw, Pl-00 681 Warsaw (Poland); Aas, A.J. [Department of Chemistry, University of Oslo, PO Box 1033, Blindern, N-0315 Oslo (Norway); Garcia-Raffi, L.M. [Instituto de Fisica Corpuscular, CSIC - Universidad de Valencia, Apdo. 22805, E-46071 Valencia (Spain); Lovhoiden, G. [Department of Physics, University of Oslo, PO Box 1048, Blindern, N-0316 Oslo (Norway); Martinez, T.; Rubio, B.; Tain, J.L. [Instituto de Fisica Corpuscular, CSIC - Universidad de Valencia, Apdo. 22805, E-46071 Valencia (Spain); Tengblad, O. [Instituto de Estructura de la Materia, CSIC, Serrano 113 bis, E-28006 Madrid (Spain); ISOLDE, PH Department, CERN, CH-1211 Geneva 23 (Switzerland)

    2008-10-15

    The low-energy structure of {sup 231}Ac has been investigated by means of {gamma} ray spectroscopy following the {beta}{sup -} decay of {sup 231}Ra. Multipolarities of 28 transitions have been established by measuring conversion electrons with a MINI-ORANGE electron spectrometer. The decay scheme of {sup 231}Ra {yields}{sup 231}Ac has been constructed for the first time. The Advanced Time Delayed {beta}{gamma}{gamma}(t) method has been used to measure the half-lives of five levels. The moderately fast B(E1) transition rates derived suggest that the octupole effects, albeit weak, are still present in this exotic nucleus.

  8. The Effective AC Response of Nonlinear Composites

    Institute of Scientific and Technical Information of China (English)

    WEI En-Bo; GU Guo-Qing

    2001-01-01

    A perturbative approach is used to study the AC response of nonlinear composite media, which obey a current-field relation of the form J = σ E + χ|E|2 E with components having nonlinear response at finite frequencies. For a sinusoidal applied field, we extend the local potential in terms of sinusoidal components at fundamental frequency and high-order harmonic frequencies to treat the nonlinear composites. For nonlinear composite media vith a low concentrations of spherical inclusions, we give the formulae of the nonlinear effective AC susceptibility χ*3ω at the third harmonic frequency.

  9. The ACS Nearby Galaxy Survey Treasury

    CERN Document Server

    Dalcanton, Julianne J; Seth, Anil C; Dolphin, Andrew; Holtzman, Jon; Rosema, Keith; Skillman, Evan D; Cole, Andrew; Girardi, Leo; Gogarten, Stephanie M; Karachentsev, Igor D; Olsen, Knut; Weisz, Daniel; Christensen, Charlotte; Freeman, Ken; Gilbert, Karoline; Gallart, Carme; Harris, Jason; Hodge, Paul; de Jong, Roelof S; Karachentseva, Valentina; Mateo, Mario; Stetson, Peter B; Tavarez, Maritza; Zaritsky, Dennis; Governato, Fabio; Quinn, Thomas

    2009-01-01

    The ACS Nearby Galaxy Survey Treasury (ANGST) is a systematic survey to establish a legacy of uniform multi-color photometry of resolved stars for a volume-limited sample of nearby galaxies (D14 million stars. In this paper we present the details of the sample selection, imaging, data reduction, and the resulting photometric catalogs, along with an analysis of the photometric uncertainties (systematic and random), for both t he ACS and WFPC2 imaging. We also present uniformly derived relative distances measured from the apparent magnitude of the TRGB.

  10. AC optik - visuaalisen identiteetin suunnittelu optikkoliikkeelle

    OpenAIRE

    Valén, Wilma

    2017-01-01

    Toteutin opinnäytetyöni yhdessä pienen loviisalaisen optikkoliikkeen, AC optikin kanssa. Opinnäytetyössäni suunnittelen AC optikille uuden visuaalisen ilmeen ja brändätyn pakkauksen, jossa silmälasit ja oheistavara on helppo luovuttaa asiakkaalle. Taustoitan aihettani yksityisyrittäjälle tärkeistä näkökulmista eli keskittymällä positiivisen asiakaskokemuksen tärkeyteen brändin rakentamisessa. Sen lisäksi käyn läpi visuaalisen identiteetin suunnittelun elementtejä ja pakkauksen asemaa brän...

  11. AC410 Unit 2 Homework Assignment

    OpenAIRE

    Laynebaril1

    2017-01-01

      AC410 Unit 2 Homework Assignment Click Link Below To Buy: http://hwcampus.com/shop/ac410-unit-2-homework-assignment/   3-31 Ron Barber, CPA, is auditing the financial statements of DGF, Inc., a publicly held company. During the course of the audit, Barber discovered that DGF has been making illegal bribes to foreign government officials to obtain business, and he reported the matter to senior management and the board of directors of DGF. Required: If management a...

  12. Control of Power Converters in AC Microgrids

    DEFF Research Database (Denmark)

    Rocabert, Joan; Luna, Alvaro; Blaabjerg, Frede

    2012-01-01

    The enabling of ac microgrids in distribution networks allows delivering distributed power and providing grid support services during regular operation of the grid, as well as powering isolated islands in case of faults and contingencies, thus increasing the performance and reliability of the ele......The enabling of ac microgrids in distribution networks allows delivering distributed power and providing grid support services during regular operation of the grid, as well as powering isolated islands in case of faults and contingencies, thus increasing the performance and reliability...

  13. Cascaded Buck-Boost AC/AC converter%级联式Buck-Boost AC/AC变换器

    Institute of Scientific and Technical Information of China (English)

    张友军; 丁明昌; 任永保; 王阿敏; 翁振明

    2010-01-01

    详细分析了Buck型和Boost型AC/AC变换器的工作原理及其控制方法,在此基础上提出了一种新型级联式Buck-Boost AC/AC变换器及其三模式控制策略.三模式控制策略是比较输入电压与基准输出电压的大小,使得变换器只有3种工作模式:Buck模式、Boost模式和滤波模式.该电路虽然由Buck型和Boost型AC/AC变换器2级变换器级联而成,并采用2级占空比调制,但实际上最多只存在一级功率变换,具有控制简单、变换效率高、开关管电压应力低等优点.仿真结果证明了级联式Buck-Boost AC/AC变换器及其控制策略的可行性和理论分析的正确性.

  14. Analysis on Belleville Spring Fracture of Controlling Gear of Gas Insulated Switchgear in 220 kV Substation%220 kV 变电站气体绝缘金属封闭开关设备操作机构碟形弹簧断裂分析

    Institute of Scientific and Technical Information of China (English)

    李文胜; 董重里; 胡平; 王伟; 林介东

    2016-01-01

    通过宏观检查、金相试验、光谱分析、洛氏硬度试验、扫描电镜观察和能谱分析等试验,对一起220 kV变电站气体绝缘金属封闭开关设备(gas insulated switchgear,GIS)操作机构碟形弹簧断裂的原因进行分析。结果表明,碟形弹簧断裂的原因可以推断是弹簧下表面外径边缘至 U 形凹槽的区域在制造过程中形成原始缺陷,此处存在应力集中现象,在使用过程中,裂纹扩展并最终导致弹簧断裂。此外,碟形弹簧的显微组织保留了明显的马氏体针状形态,还出现了少量的羽毛状回火贝氏体,这些特征表明弹簧在使用过程中较易发生脆性断裂。%This paper analyzes reasons for Belleville spring fracture of controlling gear of gas insulated switchgear in 220 kV substation by experiments of microscopic test,metallographic test,spectral analysis,Rockwell hardness test,scanning elec-tron microscope observation,energy spectrum analysis,and so on. Results indicate that reasons for Belleville spring fracture may be deduced for original defect of the area along the edge of external diameter of the lower surface of the spring to the U-shaped groove in manufacturing process where exists stress concentration,and in use procedure,cracks extend and finally cause spring fracture. In addition,microscopic structure of the Belleville spring keeps obvious martensitic acicular form and there is a little featheriness tempered bainite,which indicates that brittle fracture is easy to occur on the spring in use procedure.

  15. SINGLE PHASE HIGH FREQUENCY AC CONVERTER FOR INDUCTION HEATING APPLICATION

    Directory of Open Access Journals (Sweden)

    M.A INAYATHULLAAH,

    2010-12-01

    Full Text Available The proposed topology reduces the total harmonic distortion (THD of a high frequency AC/AC Converter well below the acceptable limit. This paper deals with a novel single phase AC/DC/AC soft switching utility frequency AC to high frequency AC converter. In this paper a single phase full bridge inverter with Vienna rectifier as front end is used instead of conventional diode bridge rectifier to provide continuous sinusoidal input current with nearly unity power factor at the source side with extremely low distortion.. This power converter is more suitable and acceptable for cost effective high frequency (HF consumer induction heating applications.

  16. YBCO thin films in ac and dc films

    CERN Document Server

    Shahzada, S

    2001-01-01

    We report studies on the dc magnetization of YBCO thin films in simultaneously applied dc and ac fields. The effect of the ac fields is to decrease the irreversible magnetization drastically leading to complete collapse of the hysteresis loops for relatively small ac fields (250e). The magnitude of the decrease depends on the component of the ac field parallel to the c-axis. The decrease is non-linear with ac amplitude and is explained in the framework of the critical state response of ultra thin films in perpendicular geometry. The ac fields increase the relaxation rapidly at short times while the long time response appears unaffected. (author)

  17. AcsA-AcsB: The core of the cellulose synthase complex from Gluconacetobacter hansenii ATCC23769.

    Science.gov (United States)

    McManus, John B; Deng, Ying; Nagachar, Nivedita; Kao, Teh-hui; Tien, Ming

    2016-01-01

    The gram-negative bacterium, Gluconacetobacter hansenii, produces cellulose of exceptionally high crystallinity in comparison to the cellulose of higher plants. This bacterial cellulose is synthesized and extruded into the extracellular medium by the cellulose synthase complex (CSC). The catalytic component of this complex is encoded by the gene AcsAB. However, several other genes are known to encode proteins critical to cellulose synthesis and are likely components of the bacterial CSC. We have purified an active heterodimer AcsA-AcsB from G. hansenii ATCC23769 to homogeneity by two different methods. With the purified protein, we have determined how it is post-translationally processed, forming the active heterodimer AcsA-AcsB. Additionally, we have performed steady-state kinetic studies on the AcsA-AcsB complex. Finally through mutagenesis studies, we have explored the roles of the postulated CSC proteins AcsC, AcsD, and CcpAx.

  18. Modeling of long High Voltage AC Underground

    DEFF Research Database (Denmark)

    Gudmundsdottir, Unnur Stella; Bak, Claus Leth; Wiechowski, W. T.

    2010-01-01

    This paper presents the work and findings of a PhD project focused on accurate high frequency modelling of long High Voltage AC Underground cables. The project is cooperation between Aalborg University and Energinet.dk. The objective of the project is to investigate the accuracy of most up to date...

  19. Protection of AC and DC Microgrids

    DEFF Research Database (Denmark)

    Beheshtaein, Siavash; Savaghebi, Mehdi; Quintero, Juan Carlos Vasquez

    2015-01-01

    In future, distributed energy resources (RESs) will be utilized at consumption points. As a consequence, power flow and fault current would be bidirectional and topologydependent; and hence the conventional protection strategies would be inefficient. This paper categorizes the main challenges in AC...

  20. 76 FR 65633 - RIN 1904-AC43

    Science.gov (United States)

    2011-10-24

    ... 1904-AC43. Comments may be submitted using any of the following methods: Federal eRulemaking Portal... and avoid the use of special characters or any form of encryption. Postal Mail: Ms. Brenda Edwards, U... FR 56678 (September 14, 2011) to make available and invite comments on the framework document...

  1. Thermal Simulation of AC Electromagnetic Contactor

    Institute of Scientific and Technical Information of China (English)

    NIUChun-ping; CHENDe-gui; ZHANGJing-shu; LIXing-wen

    2005-01-01

    Transient magnetic circuit method is adopted to calculate the power loss in winding and shading coil. Based on the analysis of heat transfer process in AC contactor, a thermal model is proposed and the temperature field distribution is simulated with 3-D FEM of ANSYS.Comparison of simulation results with measurements shows that the proposed method is effective.

  2. AC Losses of Prototype HTS Transmission Cables

    Energy Technology Data Exchange (ETDEWEB)

    Demko, J.A.; Dresner, L.; Hughey, R.L.; Lue, J.W.; Olsen, S.K.; Sinha, U.; Tolbert, J.C.

    1998-09-13

    Since 1995 Southwire Company and Oak Ridge National Laboratory (ORNL) have jointly designed, built, and tested nine, l-m long, high temperature superconducting (HTS) transmission cable prototypes. This paper summarizes the AC loss measurements of five of the cables not reported elsewhere, and compares the losses with each other and with theory developed by Dresner. Losses were measured with both a calorimetric and an electrical technique. Because of the broad resistive transition of the HTS tapes, the cables can be operated stably beyond their critical currents. The AC losses were measured in this region as well as below critical currents. Dresner's theory takes into account the broad resistive transition of the HTS tapes and calculates the AC losses both below and above the critical current. The two sets of AC 10SS data agree with each other and with the theory quite welL In particular, at low currents of incomplete penetration, the loss data agree with the theoretical prediction of hysteresis loss based on only the outer two Iayers carrying the total current.

  3. AC power generation from microbial fuel cells

    Science.gov (United States)

    Lobo, Fernanda Leite; Wang, Heming; Forrestal, Casey; Ren, Zhiyong Jason

    2015-11-01

    Microbial fuel cells (MFCs) directly convert biodegradable substrates to electricity and carry good potential for energy-positive wastewater treatment. However, the low and direct current (DC) output from MFC is not usable for general electronics except small sensors, yet commercial DC-AC converters or inverters used in solar systems cannot be directly applied to MFCs. This study presents a new DC-AC converter system for MFCs that can generate alternating voltage in any desired frequency. Results show that AC power can be easily achieved in three different frequencies tested (1, 10, 60 Hz), and no energy storage layer such as capacitors was needed. The DC-AC converter efficiency was higher than 95% when powered by either individual MFCs or simple MFC stacks. Total harmonic distortion (THD) was used to investigate the quality of the energy, and it showed that the energy could be directly usable for linear electronic loads. This study shows that through electrical conversion MFCs can be potentially used in household electronics for decentralized off-grid communities.

  4. From Beamline to Scanner with 225Ac

    Science.gov (United States)

    Robertson, Andrew K. H.; Ramogida, Caterina F.; Kunz, Peter; Rodriguez-Rodriguez, Cristina; Schaffer, Paul; Sossi, Vesna

    2016-09-01

    Due to the high linear energy transfer and short range of alpha-radiation, targeted radiation therapy using alpha-emitting pharmaceuticals that successfully target small disease clusters will kill target cells with limited harm to healthy tissue, potentially treating the most aggressive forms of cancer. As the parent of a decay chain with four alpha- and two beta-decays, 225Ac is a promising candidate for such a treatment. However, this requires retention of the entire decay chain at the target site, preventing the creation of freely circulating alpha-emitters that reduce therapeutic effect and increase toxicity to non-target tissues. Two major challenges to 225Ac pharmaceutical development exist: insufficient global supply, and the difficulty of preventing toxicity by retaining the entire decay chain at the target site. While TRIUMF works towards large-scale (C i amounts) production of 225Ac, we already use our Isotope Separation On-Line facility to provide small (overview of this research program and the journey of 225Ac from the beamline to the scanner. This research is funded by the Natural Sciences and Engineering Research Council of Canada.

  5. A dry-cooled AC quantum voltmeter

    Science.gov (United States)

    Schubert, M.; Starkloff, M.; Peiselt, K.; Anders, S.; Knipper, R.; Lee, J.; Behr, R.; Palafox, L.; Böck, A. C.; Schaidhammer, L.; Fleischmann, P. M.; Meyer, H.-G.

    2016-10-01

    The paper describes a dry-cooled AC quantum voltmeter system operated up to kilohertz frequencies and 7 V rms. A 10 V programmable Josephson voltage standard (PJVS) array was installed on a pulse tube cooler (PTC) driven with a 4 kW air-cooled compressor. The operating margins at 70 GHz frequencies were investigated in detail and found to exceed 1 mA Shapiro step width. A key factor for the successful chip operation was the low on-chip power consumption of 65 mW in total. A thermal interface between PJVS chip and PTC cold stage was used to avoid a significant chip overheating. By installing the cryocooled PJVS array into an AC quantum voltmeter setup, several calibration measurements of dc standards and calibrator ac voltages up to 2 kHz frequencies were carried out to demonstrate the full functionality. The results are discussed and compared to systems with standard liquid helium cooling. For dc voltages, a direct comparison measurement between the dry-cooled AC quantum voltmeter and a liquid-helium based 10 V PJVS shows an agreement better than 1 part in 1010.

  6. Aging, Counterfeiting Configuration Control (AC3)

    Science.gov (United States)

    2010-01-31

    relabeled fake microcircuit chips from overseas - threaten the reliability, safety, and performance of DoD systems. These systems are vulnerable... NASA , Raytheon internal, etc. Aging, Counterfeiting Configuration Control (AC3) Page 13 of 28 are important in determining the alert’s priority

  7. Implementation and Control of an AC/DC/AC Converter for Double Wound Flywheel Application

    Directory of Open Access Journals (Sweden)

    J. G. Oliveira

    2012-01-01

    Full Text Available An all-electric driveline based on a double wound flywheel, connected in series between main energy storage and a wheel motor, is presented. The flywheel works as a power buffer, allowing the battery to deliver optimized power. It also separates electrically the system in two sides, with the battery connected to the low voltage side and the wheel motor connected to the high voltage side. This paper presents the implementation and control of the AC/DC/AC converter, used to connect the flywheel high voltage windings to the wheel motor. The converter general operation and the adopted control strategy are discussed. The implementation of the AC/DC/AC converter has been described from a practical perspective. Results from experimental tests performed in the full-system prototype are presented. The prototype system is running with satisfactory stability during acceleration mode. Good efficiency and unity power factor could be achieved, based on vector control and space vector modulation.

  8. Digital model for harmonic interactions in AC/DC/AC systems

    Energy Technology Data Exchange (ETDEWEB)

    Guarini, A.P.; Rangel, R.D.; Pilotto, L.A.S.; Pinto, R.J.; Passos Junior, R. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)

    1994-12-31

    The main purpose of this paper is to present a model for calculation of HVdc converter harmonics taking into account the influence of the harmonic interactions between the ac systems in dc link transmissions. The ideas and methodologies used in the model development take into account the dc current ripple and ac voltage distortion in the ac systems. The theory of switching functions is applied to contemplate for the frequency conversions between the ac and dc sides, in an iterative process. It is possible then to obtain, even in balanced situations, non-characteristic harmonics that are produced by frequencies originated in the other terminal, which can be significant in a strongly coupled system, such as back-to-back configuration. (author) 9 refs., 3 figs.

  9. AcEST Contig - AcEST | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available [ Credits ] BLAST Search Image Search Home About Archive Update History Contact us ...contig.zip File URL: ftp://ftp.biosciencedbc.jp/archive/acest/LATEST/acestcontig....zip File size: 1.34MB Simple search URL http://togodb.biosciencedbc.jp/togodb/view/archive_acestcontig#en Da...Joomla SEF URLs by Artio About This Database Database Description Download License Update History of This Database Site Policy | Contact Us AcEST Contig - AcEST | LSDB Archive ...

  10. Dicty_cDB: FCL-AC21 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FCL (Link to library) FCL-AC21 (Link to dictyBase) - - - Contig-U15479-1 FCL-AC21E ...(Link to Original site) - - - - - - FCL-AC21E 632 Show FCL-AC21 Library FCL (Link to library) Clone ID FCL-AC2... http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC21Q.Seq.d/ Representative seq. ID FCL-AC2...1E (Link to Original site) Representative DNA sequence >FCL-AC21 (FCL-AC21Q) /CSM/FCL/FCL-AC/FCL-AC2...M/SL/SLG7-D/SLG773Q.Seq.d/ 1205 0.0 FCL-AC21 (FCL-AC21Q) /CSM/FCL/FCL-AC/FCL-AC21

  11. Morphological studies of the galaxy populations in distant "Butcher-Oemler" clusters with HST. II. AC103, AC118 and AC114 at z=0.31

    CERN Document Server

    Couch, W J; Smail, I; Ellis, Richard S; Sharples, R M

    1997-01-01

    We present new results of a program to study the detailed morphologies of galaxies in intermediate redshift clusters and hence understand the physical origin of the enhanced star formation in these environments at earlier epochs. Deep, high resolution imagery has been obtained of 3 rich clusters, AC103,AC118 & AC114 at z=0.31, using the WFPC2 on HST. For AC103 & AC118, single pointings covering a central 0.5x0.5Mpc have been obtained; for AC114, 4 pointings covering a 1.2x0.7Mpc area have been obtained, allowing the more outer regions of a distant cluster to be studied. Hubble types plus evidence for dynamical interactions and/or structural abnormalities have been determined visually for all galaxies down to R=22.25 in AC103 & AC118 and R=23.0 in AC114.We find the numbers of spirals (Sa-Sdm) in our clusters to be up to 4x higher than that seen in present-day clusters; only in the virialised core of our most massive regular cluster, AC114, do we see morphological fractions approaching those of the ...

  12. Methods for Addressing Missing Data with Applications from ACS Exams

    Science.gov (United States)

    Brandriet, Alexandra; Holme, Thomas

    2015-01-01

    As part of the ACS Examinations Institute (ACS-EI) national norming process, student performance data sets are collected from professors at colleges and universities from around the United States. Because the data sets are collected on a volunteer basis, the ACS-EI often receives data sets with only students' total scores and without the students'…

  13. Importance of Attenuation Correction (AC) for Small Animal PET Imaging

    DEFF Research Database (Denmark)

    El Ali, Henrik H.; Bodholdt, Rasmus Poul; Jørgensen, Jesper Tranekjær;

    2012-01-01

    was performed. Methods: Ten NMRI nude mice with subcutaneous implantation of human breast cancer cells (MCF-7) were scanned consecutively in small animal PET and CT scanners (MicroPETTM Focus 120 and ImTek’s MicroCATTM II). CT-based AC, PET-based AC and uniform AC methods were compared. Results: The activity...

  14. AC LED的研究现状与发展%Current research and development of AC LED

    Institute of Scientific and Technical Information of China (English)

    满瑞; 李秋俊

    2012-01-01

    介绍了AC LED的特征及其工作原理,分析了AC LED相比于DC LED的优缺点,概述了AC LED在国内外的研究进展及其应用现状,讨论了AC LED技术发展过程中面临的挑战,并展望了其发展趋势.%The characteristics and operation principles of AC LED were presented.The advantages and disadvantages of AC LED compared with the DC LED were analyzed.The development and the latest application of AC LED were described.The challenges of the competition with the traditional light source were discussed,as well as the development trend of AC LED.

  15. Improvements of KYN Maintenance Earthing Handcart Five Interlocking Control Circuit Design%KYN用检修接地手车的五防联锁控制电路的改进设计

    Institute of Scientific and Technical Information of China (English)

    熊学海

    2015-01-01

    铠装移开式交流金属封闭开关设备,是一种适用于三相交流50 Hz、12 kV、额定电流4000 A及以下的户内配电系统,是目前最常用的12 kV开关成套设备。近年来,由于本柜型的“五防”联锁不完善,经常出现事故。就该产品在“五防”联锁方面出现的新问题进行分析,着重探讨该产品配套的检修接地手车与设备之间的“五防”联锁电气改进方案。%Armoured open ac metal-enclosed switchgear is a kind of applicable to three-phase ac 50 Hz, 12 kV, rated current under 4000A and indoor distribution system,and it is the most commonly used 12 kV switch complete sets of equipment by far. In recent years, due to this type of“five prevention”interlocking is imperfect,the accidents is frequent. This paper analyzed the product in the aspect of“five prevention”interlocking new problems,and focused on the maintenance of the product form a complete set of grounding handcart“five prevention”interlock between equipment and electrical improvements.

  16. RHIC AC DIPOLE DESIGN AND CONSTRUCTION.

    Energy Technology Data Exchange (ETDEWEB)

    BAI,M.; METH,M.; PAI,C.; PARKER,B.; PEGGS,S.; ROSER,T.; SANDERS,R.; TRBOJEVIC,D.; ZALTSMAN,A.

    2001-06-18

    Two ac dipoles with vertical and horizontal magnetic field have been proposed at RHIC for applications in linear and non-linear beam dynamics and spin manipulations. A magnetic field amplitude of 380 Gm is required to produce a coherent oscillation of 5 times the rms beam size at the top energy. We take the ac dipole frequency to be 1.0% of the revolution frequency away from the betatron frequency. To achieve the strong magnetic field with minimum power loss, an air-core magnet with two seven turn winding of low loss Litz wire resonating at 64 kHz is designed. The system is also designed to allow one to connect the two magnet winding in series to resonate at 37 kHz for the spin manipulation. Measurements of a half length prototype magnet are also presented.

  17. Nanorod dynamics in ac electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Ruda, H E; Shik, A [Centre for Advanced Nanotechnology, University of Toronto, Toronto, M5S 3E3 (Canada)

    2010-06-11

    Metal and semiconductor nanorods polarized by an external electric field tend to align parallel to this field. We derived the equation of motion for this alignment, taking into account electrostatic forces, thermal fluctuations and viscous resistance of the liquid the nanorods are suspended in. It was solved for a strong ac electric field, as well as for the combination of strong dc and weak ac fields. The results were used for calculations of the capacity of the nanorod solution, its frequency dispersion and dependence on the field strength. Modification of the nanorod absorption spectra under the influence of an electric field was also considered. It was shown that metal nanorods in laser radiation, with the frequency belonging to the interval between longitudinal and transverse plasmon modes, tend to align perpendicular, rather than parallel, to the optical electric field.

  18. 78 FR 49318 - Availability of Draft Advisory Circular (AC) 90-106A and AC 20-167A

    Science.gov (United States)

    2013-08-13

    ... Systems (78 FR 34935-34958) (Docket No.: FAA-2013-0485; Notice No. 1209). AC 90-106A, Enhanced Flight... the Federal Register published on April 11, 2000 (65 FR 19477-19478), as well as at http://DocketsInfo... Federal Aviation Administration Availability of Draft Advisory Circular (AC) 90-106A and AC 20-...

  19. AC plasma anemometer—characteristics and design

    Science.gov (United States)

    Marshall, Curtis; Matlis, Eric; Corke, Thomas; Gogineni, Sivaram

    2015-08-01

    The characteristics and design of a high-bandwidth flow sensor that uses an AC glow discharge (plasma) as the sensing element is presented. The plasma forms in the air gap between two protruding low profile electrodes attached to a probe body. The output from the anemometer is an amplitude modulated version of the AC voltage input that contains information about the mean and fluctuating velocity components. The anemometer circuitry includes resistance and capacitance elements that simulate a dielectric-barrier to maintain a diffuse plasma, and a constant-current feedback control that maintains operation within the desired glow discharge regime over an extended range of air velocities. Mean velocity calibrations are demonstrated over a range from 0 to 140 m s-1. Over this velocity range, the mean output voltage varied linearly with air velocity, providing a constant static sensitivity. The effect of the electrode gap and input AC carrier frequency on the anemometer static sensitivity and dynamic response are investigated. Experiments are performed to compare measurements obtained with a plasma sensor operating at two AC carrier frequencies against that of a constant-temperature hot-wire. All three sensors were calibrated against the same known velocity reference. An uncertainty based on the standard deviation of the velocity calibration fit was applied to the mean and fluctuating velocity measurements of the three sensors. The motivation is not to replace hot-wires as a general measurement tool, but rather as an alternative to hot-wires in harsh environments or at high Mach numbers where they either have difficulty in surviving or lack the necessary frequency response.

  20. Lazy AC-Pattern Matching for Rewriting

    OpenAIRE

    Walid Belkhir; Alain Giorgetti

    2012-01-01

    We define a lazy pattern-matching mechanism modulo associativity and commutativity. The solutions of a pattern-matching problem are stored in a lazy list composed of a first substitution at the head and a non-evaluated object that encodes the remaining computations. We integrate the lazy AC-matching in a strategy language: rewriting rule and strategy application produce a lazy list of terms.

  1. Lazy AC-Pattern Matching for Rewriting

    Directory of Open Access Journals (Sweden)

    Walid Belkhir

    2012-04-01

    Full Text Available We define a lazy pattern-matching mechanism modulo associativity and commutativity. The solutions of a pattern-matching problem are stored in a lazy list composed of a first substitution at the head and a non-evaluated object that encodes the remaining computations. We integrate the lazy AC-matching in a strategy language: rewriting rule and strategy application produce a lazy list of terms.

  2. Cryocooled Josephson standards for AC voltage metrology

    Science.gov (United States)

    Durandetto, P.; Sosso, A.; Monticone, E.; Trinchera, B.; Fretto, M.; Lacquaniti, V.

    2017-05-01

    The Josephson effect is worldwide used as a basis for constant reference voltages in national metrological institutes and in calibration laboratories of industry. Research on Josephson voltage standards is aiming at a fundamental change also in the metrology of the volt for AC and arbitrary waveforms: programmable Josephson voltage standards converting a digital code into a quantum-accurate stepwise waveform are already available in primary laboratories and even more advanced standards for converting sub-nanosecond binary coded pulses into any arbitrary signal with quantum accuracy are now actively developed and tested. A new experimental setup based on a two-stage Gifford-McMahon cryocooler has been developed at INRiM for the operation of AC-Josephson voltage standards. Among its distinct features, the possibility of employing both the aforementioned techniques (programmable and pulsed Josephson voltage standards) is particularly interesting. Quantum-based AC voltage sine waves have been synthesized with both programmable and pulse-driven arrays, although their accuracy is still limited by thermal oscillations due to the cryocooler piston motion.

  3. The Hubble Legacy Archive ACS Grism Data

    CERN Document Server

    Kuemmel, M; Fosbury, R; Haase, J; Hook, R N; Kuntschner, H; Lombardi, M; Micol, A; Nilsson, K K; Stoehr, F; Walsh, J R

    2011-01-01

    A public release of slitless spectra, obtained with ACS/WFC and the G800L grism, is presented. Spectra were automatically extracted in a uniform way from 153 archival fields (or "associations") distributed across the two Galactic caps, covering all observations to 2008. The ACS G800L grism provides a wavelength range of 0.55-1.00 \\mu$m, with a dispersion of $40 \\ \\AA / pixel$ and a resolution of $\\sim 80\\ \\AA$ for point-like sources. The ACS G800L images and matched direct images were reduced with an automatic pipeline that handles all steps from archive retrieval, alignment and astrometric calibration, direct image combination, catalogue generation, spectral extraction and collection of metadata. The large number of extracted spectra (73,581) demanded automatic methods for quality control and an automated classification algorithm was trained on the visual inspection of several thousand spectra. The final sample of quality controlled spectra includes 47,919 datasets (65% of the total number of extracted spect...

  4. AC susceptibilities of grain-textured superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, N. [Department of Electrical Engineering, Kyushu Sangyo University, 2-3-1 Matsukadai, 813-8503 Fukuoka (Japan)], E-mail: saka@te.kyusan-u.ac.jp; Fukuda, Y.; Koga, M.; Akune, T. [Department of Electrical Engineering, Kyushu Sangyo University, 2-3-1 Matsukadai, 813-8503 Fukuoka (Japan); Khan, H.R. [Institut von Ionenstrahl und Vakuum Technologie, 73728 Esslingen (Germany); Lueders, K. [Freie Universitaet Berlin, Arnimallee, Fac.Physik, D-14195 Berlin (Germany)

    2008-09-15

    In-phase {chi}{sub n}' and out-phase {chi}{sub n}'' components of nth harmonics of AC susceptibility with measuring parameters of a DC magnetic field B{sub dc}, an amplitude B{sub a} and a frequency f of the superimposed AC magnetic fields give substantial information of the superconducting properties. In low-T{sub c} metallic superconductors, {chi}{sub 1}' shows smooth transition and {chi}{sub 1}'' does single peak. High-T{sub c} oxide superconductors with anisotropic and grain-textured structures show deformed complex characteristics. Double peaks in {chi}{sub 1}'' and shoulders in {chi}{sub 1}' appear in AC susceptibility of Hg-1223 superconductors. Instead of simple Bean model, a grained model, where the superconducting grains are immersed in weak superconducting matrix, are proposed. The susceptibilities numerically analyzed using the model show varied and deformed curves and are successfully compared with the measured results.

  5. 单相直接AC-AC变换器的实现与分析%The Implementation and Analysis of Simple Phase Direct AC-AC Converter

    Institute of Scientific and Technical Information of China (English)

    万衡; 喻嬿; 黄道

    2002-01-01

    针对传统AC-DC-AC变换存在的缺陷,采用高频调制直接AC-AC变换技术,实现了两种不同结构的单相AC-AC直接变换器,对其特点和仿真结果进行了分析,并探讨了应用前景.

  6. 美式箱变、户外环网柜交流无间隙氧化锌避雷器选用%Selection of AC Non-Gap Metal Oxide Surge Arrester for US Package Substation and Outdoor Ringed Network Switchgear

    Institute of Scientific and Technical Information of China (English)

    朱辉

    2007-01-01

    文章针对美式箱变、户外环网柜配用的交流无间隙氧化锌避雷器主要电气指标的选择,从国家相关标准的规定和运行经验的角度,分析和对比了国产和进口两系列产品,说明了避雷器应优先采用符合国家标准的国产品,若确实需要用进口产品时则应选择能满足我国国标各项指标要求的且残压较小的产品.

  7. Molecular biology of maize Ac/Ds elements: an overview.

    Science.gov (United States)

    Lazarow, Katina; Doll, My-Linh; Kunze, Reinhard

    2013-01-01

    Maize Activator (Ac) is one of the prototype transposable elements of the hAT transposon superfamily, members of which were identified in plants, fungi, and animals. The autonomous Ac and nonautonomous Dissociation (Ds) elements are mobilized by the single transposase protein encoded by Ac. To date Ac/Ds transposons were shown to be functional in approximately 20 plant species and have become the most widely used transposable elements for gene tagging and functional genomics approaches in plants. In this chapter we review the biology, regulation, and transposition mechanism of Ac/Ds elements in maize and heterologous plants. We discuss the parameters that are known to influence the functionality and transposition efficiency of Ac/Ds transposons and need to be considered when designing Ac transposase expression constructs and Ds elements for application in heterologous plant species.

  8. Development of a hardware-based AC microgrid for AC stability assessment

    Science.gov (United States)

    Swanson, Robert R.

    As more power electronic-based devices enable the development of high-bandwidth AC microgrids, the topic of microgrid power distribution stability has become of increased interest. Recently, researchers have proposed a relatively straightforward method to assess the stability of AC systems based upon the time-constants of sources, the net bus capacitance, and the rate limits of sources. In this research, a focus has been to develop a hardware test system to evaluate AC system stability. As a first step, a time domain model of a two converter microgrid was established in which a three phase inverter acts as a power source and an active rectifier serves as an adjustable constant power AC load. The constant power load can be utilized to create rapid power flow transients to the generating system. As a second step, the inverter and active rectifier were designed using a Smart Power Module IGBT for switching and an embedded microcontroller as a processor for algorithm implementation. The inverter and active rectifier were designed to operate simultaneously using a synchronization signal to ensure each respective local controller operates in a common reference frame. Finally, the physical system was created and initial testing performed to validate the hardware functionality as a variable amplitude and variable frequency AC system.

  9. 隔离式SEPIC三电平AC-AC变换器的研究%Research of Isolated SEPIC Three-level AC - AC Converter

    Institute of Scientific and Technical Information of China (English)

    周振军; 李磊

    2011-01-01

    电力电子装置已在电力系统中得到了越来越广泛的应用,代表之一就是交流调压稳压装置.但是目前的交流调压稳压器多数采用AC-DC-AC的变换方式,这种调压稳压器不仅体积大、噪音大,而且开关管的电压应力大、输出电压波形质量低.提出了一种新型的隔离式交-交变换器,它是在sepic变换器(单端初级电感转换器)的基础上引入了推挽式变压器实现电气隔离.分析了工作原理,给出了控制策略,并通过仿真论证了变换器开关管电压应力小、输出电压波形质量高等特点.%Power electronics have been more widely used in power systems. One representative of power electronics is AC voltage regulator. But the AC - DC - AC conversion type is widely used for voltage regulator now. These AC voltage regulator not only have big bulk and high noise,but also with high power switch voltage stress and low quality of output waveform. To solve these problems)an isolated three-level AC - AC direct converter was proposed. It joined the push-pull transformer to achieve electrical isolation based on sepic AC -AC converter. Its operation principle and control strategies of the converter were investigated. By modeling and simulation,the performances of the AC - AC converter were verified, such as low switch voltage stress, high quality of output waveform and so on.

  10. MATHEMATICAL MODELING OF AC ELECTRIC POINT MOTOR

    Directory of Open Access Journals (Sweden)

    S. YU. Buryak

    2014-03-01

    Full Text Available Purpose. In order to ensure reliability, security, and the most important the continuity of the transportation process, it is necessary to develop, implement, and then improve the automated methods of diagnostic mechanisms, devices and rail transport systems. Only systems that operate in real time mode and transmit data on the instantaneous state of the control objects can timely detect any faults and thus provide additional time for their correction by railway employees. Turnouts are one of the most important and responsible components, and therefore require the development and implementation of such diagnostics system.Methodology. Achieving the goal of monitoring and control of railway automation objects in real time is possible only with the use of an automated process of the objects state diagnosing. For this we need to know the diagnostic features of a control object, which determine its state at any given time. The most rational way of remote diagnostics is the shape and current spectrum analysis that flows in the power circuits of railway automatics. Turnouts include electric motors, which are powered by electric circuits, and the shape of the current curve depends on both the condition of the electric motor, and the conditions of the turnout maintenance. Findings. For the research and analysis of AC electric point motor it was developed its mathematical model. The calculation of parameters and interdependencies between the main factors affecting the operation of the asynchronous machine was conducted. The results of the model operation in the form of time dependences of the waveform curves of current on the load on engine shaft were obtained. Originality. During simulation the model of AC electric point motor, which satisfies the conditions of adequacy was built. Practical value. On the basis of the constructed model we can study the AC motor in various mode of operation, record and analyze current curve, as a response to various changes

  11. Flexible AC transmission systems modelling and control

    CERN Document Server

    Zhang, Xiao-Ping; Pal, Bikash

    2012-01-01

    The extended and revised second edition of this successful monograph presents advanced modeling, analysis and control techniques of Flexible AC Transmission Systems (FACTS). The book covers comprehensively a range of power-system control problems: from steady-state voltage and power flow control, to voltage and reactive power control, to voltage stability control, to small signal stability control using FACTS controllers. In the six years since the first edition of the book has been published research on the FACTS has continued to flourish while renewable energy has developed into a mature and

  12. Composite Based EHV AC Overhead Transmission Lines

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard

    Overhead lines at transmission level are the backbone of any national power grid today. New overhead line projects however are at the same time subject to ever greater public resistance due to the lines environmental impact. As full undergrounding of transmission lines at extra high voltage (EHV...... and analysed with regard to the possibilities, limitations and risks widespread application of composite materials on EHV AC overhead transmission lines may present. To form the basis for evaluation of the useability of composite materials, dierent overhead line projects aimed at reducing the environmental...

  13. DC injection into low voltage AC networks

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This report summarises the results of a study investigating the impact of levels of injected DC current injections on a low voltage AC distribution network systems in order to recommend acceptable limits of DC from microgeneration. Relevant literature is reviewed, and the impact of DC levels in distribution transformers, transformer modelling, and instrumental transformers are discussed. The impact of DC in residual current devices (RCD) and in domestic electricity watt hour meters is examined along with DC enhanced corrosion, corrosion failure, and the measurement of DC current injection. Sources of DC injection outlined include DC from computer power supplies, network faults, geomagnetic phenomena, lighting circuits/dimmers, and embedded generators.

  14. POWER FACTOR IMPROVEMENT IN THREE PHASE AC-AC CONVERTER THROUGH MODIFIED SPWM

    Directory of Open Access Journals (Sweden)

    P.VASUKI,

    2011-02-01

    Full Text Available Recently, a new generation of ac-ac single-phase and three-phase power converters with more commutations per half cycle has been proposed for ac power due to the increasing availability and power capability of high frequency controlled-on and off power emiconductor switching devices. This paper presents three phase ac-acconverter whose control strategy is based on modified sinusoidal ulse-width modulation switching technique. As majority of the industrial loads are being inductive, the power factor is less. To improve the power factor, the delayed current is shifted to the input voltage, through a modification of the classical sinusoidal pulse width modulation switching technique. In this way, the decrease in the phase angle between the input current and voltage is feasible, and consequently, high cost compensation capacitors can be avoided. The improvement of power factor through this switching technique on the proposed converter is investigated and verified via simulation using the software Matlab/Simulink.

  15. Research on the Mechanical State Evaluation Method of High Voltage Switchgear Based on Kendall Correlation Coefficient%基于肯德尔相关系数的高压开关设备机械状态评估方法研究

    Institute of Scientific and Technical Information of China (English)

    孙银山; 张文涛; 张一茗; 于维娟; 刘逸凡

    2014-01-01

    智能高压开关设备在线评估技术是进行故障诊断和实施状态检修的前提和基础,采用了一种基于肯德尔相关系数计算曲线相似度的方法,以本公司自主研制开发的126kV智能隔离断路器为研究对象,在大量现场实验数据的基础上对智能隔离断路器机械状态评估进行了分析和探索。实验结果表明具有非常良好的实用性和可移植性,执行速度快,可靠性高等诸多优点,在开关设备评估中具有很好的应用前景。%Online evaluation technique for the intelligent high voltage switchgear is the premise and foundation for fault diagnosis and implementation of condition-based maintenance.With respect to the intelligent 126kV disconnecting circuit breaker developed by our company,this paper uses a method for calculating the curve similarity based on Kendall correlation coefficient to analyze and explore the evaluation of mechanical state of the intelligent discounting circuit breaker on the basis of lots of site experiment data. Experimental results indicate that this evaluation approach has excellent usability and transportability,high execution speed and high reliability,and has a good perspective of application in the evaluation of switching devices.

  16. Cascading failures in ac electricity grids

    Science.gov (United States)

    Rohden, Martin; Jung, Daniel; Tamrakar, Samyak; Kettemann, Stefan

    2016-09-01

    Sudden failure of a single transmission element in a power grid can induce a domino effect of cascading failures, which can lead to the isolation of a large number of consumers or even to the failure of the entire grid. Here we present results of the simulation of cascading failures in power grids, using an alternating current (AC) model. We first apply this model to a regular square grid topology. For a random placement of consumers and generators on the grid, the probability to find more than a certain number of unsupplied consumers decays as a power law and obeys a scaling law with respect to system size. Varying the transmitted power threshold above which a transmission line fails does not seem to change the power-law exponent q ≈1.6 . Furthermore, we study the influence of the placement of generators and consumers on the number of affected consumers and demonstrate that large clusters of generators and consumers are especially vulnerable to cascading failures. As a real-world topology, we consider the German high-voltage transmission grid. Applying the dynamic AC model and considering a random placement of consumers, we find that the probability to disconnect more than a certain number of consumers depends strongly on the threshold. For large thresholds the decay is clearly exponential, while for small ones the decay is slow, indicating a power-law decay.

  17. Electrothermally driven flows in ac electrowetting.

    Science.gov (United States)

    García-Sánchez, Pablo; Ramos, Antonio; Mugele, Frieder

    2010-01-01

    Mixing within sessile drops can be enhanced by generating internal flow patterns using ac electrowetting. While for low ac frequencies, the flow patterns have been attributed to oscillations of the drop surface, we provide here the driving mechanism of the hitherto unexplained high-frequency flows. We show that: (1) the electric field in the liquid bulk becomes important, leading to energy dissipation due to Joule heating and a temperature increase of several degrees Celsius, and (2) the fluid flow at these frequencies is generated by electrothermal effect, i.e., gradients in temperature give rise to gradients in conductivity and permittivity, the electric field acting on these inhomogeneities induces an electrical body force that generates the flow. We solved numerically the equations for the electric, temperature and flow fields. The temperature is obtained from a convection-diffusion equation where Joule heating is introduced as a source term. From the solution of the electric field and the temperature, we compute the electrical force that acts as a body force in Stokes equations. Our numerical results agree with previous experimental observations.

  18. Djungle power. A more remote AC bus

    Energy Technology Data Exchange (ETDEWEB)

    Boehnke, Heinz W. [Technosol, Jork (Germany)

    2010-07-01

    The Dzanga-Sangha Reserve in the Central African Republic is probably one of the world's most remote protected rainforest areas, much to the benefit of the rare species of lowland gorilla, forest elephant and local pygmy population Ba'Aka. The park is co-managed by the ''WWF-World Wide Fund for Nature'' with sponsoring from the German Regenwald-Stiftung. In 2008 wwf decided to switch from the old, failing generator supply to a solar hybrid mini-grid, along with stringent measures of energy conservation and management. After a careful energy audit Technosol designed an AC-bus system with a 22 kWp PV generator which should overcome the dependency on the old generators and their fuel demands. For 15 buildings, an entirely new distribution network was installed, state of the art energy saving devices introduced and an energy metering system deviced. The installation is operating since August 2009. In such remote locations, the reliability of the AC-bus over other generator-based solutions will be demonstrated and with the support of international organisations like the wwf the practical application of solar hybrid supply becomes a landmark of sustainable energy concepts. (orig.)

  19. Magnetic irreversibility in granular superconductors: ac susceptibility study

    Energy Technology Data Exchange (ETDEWEB)

    Perez, F.; Obradors, X.; Fontcuberta, J. (ICMAB, CSIC, Bellaterra, Barcelona (Spain)); Vallet, M.; Gonzalez-Calbet, J. (Lab. Magnetismo Aplicado, RENFE-U.C. Madrid, Las Matas (Spain))

    1991-12-01

    Ac susceptibility measurements of a ceramic weak-coupled superconductor in very low ac fields (2mG, 111Hz) are reported. We present evidence for the observation of the magnetic irreversibility following a ZFC-FC thermal cycling by means of ac susceptibilty measurements. It is shown that this technique also reflect local magnetic field effects in granular superconductors, as previously suggested in microwave surface resistance and I-V characteristics. (orig.).

  20. Transport AC Losses in Striated YBCO Coated Conductors (Postprint)

    Science.gov (United States)

    2012-02-01

    AFRL-RZ-WP-TP-2012-0124 TRANSPORT AC LOSSES IN STRIATED YBCO COATED CONDUCTORS (POSTPRINT) G.A. Levin and P.N. Barnes Mechanical Energy...TRANSPORT AC LOSSES IN STRIATED YBCO COATED CONDUCTORS (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...2006. 14. ABSTRACT DC current-voltage characteristics and transport ac losses of striated and non-striated Y1Ba2Cu3O7-δ ( YBCO ) coated conductors

  1. GIS在局部放电下的SF6气体分解产物实验研究%Experimental Study on Relationship of SF6 Decomposition Products and Partial Discharge in Gas Insulated Switchgear

    Institute of Scientific and Technical Information of China (English)

    鲁钢; 郭江涛; 孙福军; 颜湘莲; 陈海伦

    2013-01-01

    A 126 kV AC power frequency power supply,a GIS partial discharge testing platform,and a gas detection system are designed to simulate the fault state of discharge to ground.Subsequently,SF6 decomposed characteristic gas components induced by partial discharge are analyzed quantitatively,where the intensity of partial discharge is monitored with the pulse current method.The results show that:①The characteristic gas components from partial discharge-induced SF6 decomposition are SOF2,SO2,and S2OF10;②The volume fractions of SOF2 and SO2 exhibit positive correlation with duration and intensity of partial discharge; ③Adsorbent imposes effect on measurement of SF6 decomposition products.%笔者使用自行设计126 kV交流工频电源和GIS局部放电实体实验平台以及气体分析检测系统,模拟对地放电故障状态,对局部放电引起的SF6分解物特征组份气体进行定性定量分析,用脉冲电流法对局部放电强度进行监视,得到局部放电引起SF6气体分解物特征组份及变化规律.研究表明:局部放电致使SF6气体发生分解,特征组分为SOF2、SO2、S2OF10,SOF2、SO2与局放持续时间、局放强度呈现正相关性,吸附剂对于SF6分解物检测有影响.

  2. AC electric motors control advanced design techniques and applications

    CERN Document Server

    Giri, Fouad

    2013-01-01

    The complexity of AC motor control lies in the multivariable and nonlinear nature of AC machine dynamics. Recent advancements in control theory now make it possible to deal with long-standing problems in AC motors control. This text expertly draws on these developments to apply a wide range of model-based control designmethods to a variety of AC motors. Contributions from over thirty top researchers explain how modern control design methods can be used to achieve tight speed regulation, optimal energetic efficiency, and operation reliability and safety, by considering online state var

  3. Autonomous Operation of Hybrid Microgrid With AC and DC Subgrids

    DEFF Research Database (Denmark)

    Chiang Loh, Poh; Li, Ding; Kang Chai, Yi

    2013-01-01

    This paper investigates on power-sharing issues of an autonomous hybrid microgrid. Unlike existing microgrids which are purely ac, the hybrid microgrid studied here comprises dc and ac subgrids interconnected by power electronic interfaces. The main challenge here is to manage power flows among all...... sources distributed throughout the two types of subgrids, which is certainly tougher than previous efforts developed for only ac or dc microgrid. This wider scope of control has not yet been investigated, and would certainly rely on the coordinated operation of dc sources, ac sources, and interlinking...

  4. AC Own Motion Percentage of Randomly Sampled Cases

    Data.gov (United States)

    Social Security Administration — Longitudinal report detailing the numbers and percentages of Appeals Council (AC) own motion review actions taken on un-appealed favorable hearing level decisions...

  5. [Intestinal occlusion and abdominal compartment syndrome (ACS)].

    Science.gov (United States)

    Stagnitti, Franco

    2009-01-01

    Intestinal occlusion is defined as an independent predictive factor of intra-abdominal hypertension (IAH) which represents an independent predictor of mortality. Baggot in 1951 classified patients operated with intestinal occlusion as being at risk for IAH ("abdominal blow-out"), recommending them for open abdomen surgery proposed by Ogilvie. Abdominal surgery provokes IAH in 44.7% of cases with mortality which, in emergency, triples with respect to elective surgery (21.9% vs 6.8%). In particular, IAH is present in 61.2% of ileus and bowel distension and is responsible for 52% of mortality (54.8% in cases with intra-abdominal infection). These patients present with an increasing intra-abdominal pressure (IAP) which, over 20-25 mmHg, triggers an Abdominal Compartment Syndrome (ACS) with altered functions in some organs arriving at Multiple Organ Dysfunction Syndrome (MODS). The intestine normally covers 58% of abdominal volume but when there is ileus distension, intestinal pneumatosis develops (third space) which can occupy up to 90% of the entire cavity. At this moment, Gastro Intestinal Failure (GIF) can appear, which is a specific independent risk factor of mortality, motor of "Organ Failure". The pathophysiological evolution has many factors in 45% of cases: intestinal pneumatosis is associated with mucosal and serous edema, capillary leakage with an increase in extra-cellular volume and peritoneal fluid collections (fourth space). The successive loss of the mucous barrier permits a bacterial translocation which includes bacteria, toxins, pro-inflammatory factors and oxygen free radicals facilitating the passage from an intra-abdominal to inter-systemic vicious cyrcle. IAH provokes the raising of the diaphragm, and vascular and visceral compressions which induce hypertension in the various spaces with compartmental characteristics. These trigger hypertension in the renal, hepatic, pelvic, thoracic, cardiac, intracranial, orbital and lower extremity areas, giving

  6. A Non-linear Controller for Single-Phase AC-AC Power Converter to meet UPS Performance Index

    Directory of Open Access Journals (Sweden)

    Abdelhafid Ait Elmahjoub

    2012-07-01

    Full Text Available This article focuses on AC-AC power converter that can be used for uninterruptible power supply (UPS. The converter is built on two stages: a AC-DC input stage and a DC-AC output stage. The two blocks are connected by an intermediate DC bus. The aim of control is threefold: i power factor correction ii regulation of DC bus iii generating a sinusoidal voltage at the output. The synthesis of controllers has been achieved through the technique of nonlinear backstepping control. A detailed analysis of the stability control system is presented. The performances of regulators have been validated by numerical simulation in MATLAB / SIMULINK.

  7. AC Dielectrophoresis Using Elliptic Electrode Geometry

    Directory of Open Access Journals (Sweden)

    S. M. Rezaul Hasan

    2011-01-01

    Full Text Available This paper presents negative AC dielectrophoretic investigations using elliptic electrode geometry. Simulations of the electric field gradient variation using various ratios of the semimajor and the semiminor axis were carried out to determine the optimum elliptic geometry for the dielectrophoretic electrokinetics of specimen in an assay with laminar (low Reynolds number fluid flow. Experimental setup of the elliptic electrode assembly using PCB fabrication and electrokinetic accumulation of specimen in a dielectrophoretic cage is also being reported. Using an actuating signal between 1 kHz and 1 MHz, successful trapping of 45 μm polystyrene beads suspended in distilled water was demonstrated due to negative dielectrophoresis near 100 kHz using the novel elliptic electrode.

  8. Effective ac response in weakly nonlinear composites

    Energy Technology Data Exchange (ETDEWEB)

    Wei Enbo [Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Yang Zidong [College of Power Engineering, University of Shanghai Science and Technology, Shanghai 200093 (China); Gu Guoqing [Information College of Science and Technology, East China Normal University, Shanghai 200062 (China)

    2004-01-07

    The perturbation method is developed to deal with the problem of determining the effective nonlinear conductivity of Kerr-like nonlinear media under an external ac electric field. As an example, we have considered the cylindrical inclusion embedded in a host under the sinusoidal external field E{sub 1} sin (<{omega}t) + E{sub 3} sin (3<{omega}t) with frequencies{omega} and 3{omega}. The potentials of composites at higher harmonics are derived in both local inclusion particle and host regions. The effective responses of bulk nonlinear composites at basic frequency and harmonics are given for cylindrical composites in the dilute limit. Moreover, the relationships between the nonlinear effective responses at the basic frequency and the third harmonics are derived.

  9. Fuzzy efficiency optimization of AC induction motors

    Science.gov (United States)

    Jani, Yashvant; Sousa, Gilberto; Turner, Wayne; Spiegel, Ron; Chappell, Jeff

    1993-01-01

    This paper describes the early states of work to implement a fuzzy logic controller to optimize the efficiency of AC induction motor/adjustable speed drive (ASD) systems running at less than optimal speed and torque conditions. In this paper, the process by which the membership functions of the controller were tuned is discussed and a controller which operates on frequency as well as voltage is proposed. The membership functions for this dual-variable controller are sketched. Additional topics include an approach for fuzzy logic to motor current control which can be used with vector-controlled drives. Incorporation of a fuzzy controller as an application-specific integrated circuit (ASIC) microchip is planned.

  10. ac impedance of the carbon monofluoride electrode

    Science.gov (United States)

    Suchanski, M. R.

    1985-09-01

    The ac impedance of carbon monofluoride (CF) half-cells and Li/CF batteries that contain 1M LiBF4/4-butyrolactone electrolyte was measured as a function of state of charge. The nonfaradaic components of the CF half-cell impedance were resolved with the aid of a one-dimensional macroscopic treatment of a porous electrode. The values of the nonfaradaic components and their variation with charge withdrawn provide information concerning the nature of cathode discharge products, the degree of tortuosity in the cathode and separator matrices, and the cathode failure mechanism. The CF electrode capacitance, as measured by the low frequency quadrature impedance, can serve as a semiquantitative measure of battery state of charge under certain conditions.

  11. The AC and DC Conductivity of Nanocomposites

    Directory of Open Access Journals (Sweden)

    David S. McLachlan

    2007-01-01

    Full Text Available The microstructures of binary (conductor-insulator composites, containing nanoparticles, will usually have one of two basic structures. The first is the matrix structure where the nanoparticles (granules are embedded in and always coated by the matrix material and there are no particle-particle contacts. The AC and DC conductivity of this microstructure is usually described by the Maxwell-Wagner/Hashin-Shtrikman or Bricklayer model. The second is a percolation structure, which can be thought to be made up by randomly packing the two types of granules (not necessarily the same size together. In percolation systems, there exits a critical volume fraction below which the electrical properties are dominated by the insulating component and above which the conducting component dominates. Such percolation systems are best analyzed using the two-exponent phenomenological percolation equation (TEPPE. This paper discusses all of the above and addresses the problem of how to distinguish among the microstructures using electrical measurements.

  12. Transcranial alternating current stimulation (tACS

    Directory of Open Access Journals (Sweden)

    Andrea eAntal

    2013-06-01

    Full Text Available Transcranial alternating current stimulation (tACS seems likely to open a new era of the field of noninvasive electrical stimulation of the human brain by directly interfering with cortical rhythms. It is expected to synchronize (by one single resonance frequency or desynchronize (e.g. by the application of several frequencies cortical oscillations. If applied long enough it may cause neuroplastic effects. In the theta range it may improve cognition when applied in phase. Alpha rhythms could improve motor performance, whereas beta intrusion may deteriorate them. TACS with both alpha and beta frequencies has a high likelihood to induce retinal phosphenes. Gamma intrusion can possibly interfere with attention. Stimulation in the ripple range induces intensity dependent inhibition or excitation in the motor cortex most likely by entrainment of neuronal networks, whereas stimulation in the low kHz range induces excitation by neuronal membrane interference. TACS in the 200 kHz range may have a potential in oncology.

  13. Wind-powered asynchronous AC/DC/AC converter system. [for electric power supply regulation

    Science.gov (United States)

    Reitan, D. K.

    1973-01-01

    Two asynchronous ac/dc/ac systems are modelled that utilize wind power to drive a variable or constant hertz alternator. The first system employs a high power 60-hertz inverter tie to the large backup supply of the power company to either supplement them from wind energy, storage, or from a combination of both at a preset desired current; rectifier and inverter are identical and operate in either mode depending on the silicon control rectifier firing angle. The second system employs the same rectification but from a 60-hertz alternator arrangement; it provides mainly dc output, some sinusoidal 60-hertz from the wind bus and some high harmonic content 60-hertz from an 800-watt inverter.

  14. Three-Level AC-DC-AC Z-Source Converter Using Reduced Passive Component Count

    DEFF Research Database (Denmark)

    Loh, Poh Chiang; Gao, Feng; Tan, Pee-Chin;

    2007-01-01

    This paper presents a three-level ac-dc-ac Z-source converter with output voltage buck-boost capability. The converter is implemented by connecting a low cost front-end diode rectifier to a neutral-point-clamped inverter through a single X-shaped LC impedance network. The inverter is controlled...... to switch with a three-level output voltage, where the middle neutral potential is uniquely tapped from the star-point of a wye-connected capacitive filter placed before the front-end diode rectifier for input current filtering. Through careful control, the resulting converter can accurately produce...... the correct volt-sec average at its output, while simultaneously achieving inductive voltage boosting. More interestingly, these performance features are achieved with no increase in the number of semiconductor commutations, and hence no increase in switching losses. The proposed converter therefore offers...

  15. Equivalent circuit models for ac impedance data analysis

    Science.gov (United States)

    Danford, M. D.

    1990-01-01

    A least-squares fitting routine has been developed for the analysis of ac impedance data. It has been determined that the checking of the derived equations for a particular circuit with a commercially available electronics circuit program is essential. As a result of the investigation described, three equivalent circuit models were selected for use in the analysis of ac impedance data.

  16. A remark on Kov\\'acs' vanishing theorem

    CERN Document Server

    Fujino, Osamu

    2012-01-01

    We give an alternative proof of Kov\\'acs' vanishing theorem. Our proof is based on the standard arguments of the minimal model theory. We do not need the notion of Du Bois pairs. We reduce Kov\\'acs' vanishing theorem to the well-known relative Kawamata--Viehweg--Nadel vanishing theorem.

  17. 40 CFR Appendixes A-C to Part 403 - [Reserved

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true A Appendixes A-C to Part 403 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PRE-TREAT-MENT REGULATIONS FOR EXIST-ING AND NEW SOURCES OF POLLUTION Appendixes A-C to Part 403 ...

  18. Flexible AC transmission systems: the state of the art

    Energy Technology Data Exchange (ETDEWEB)

    Edris, Abdel-Aty [Electric Power Research Inst., Palo Alto, CA (United States). Electric Systems Division

    1994-12-31

    Flexible AC transmission systems (FACTS) is a concept promoting the use of power electronic controllers to enhance the controllability and usable capacity of AC transmission. This paper presents the state of the art of FACTS and the status of the current projects for the application of the FACTS controllers in transmission systems. (author) 8 refs., 8 figs.

  19. Considerations for an Ac Dipole for the LHC

    CERN Document Server

    Bai, M; Fischer, W; Oddo, P; Schmickler, Hermann; Serrano, J; Jansson, A; Syphers, M; Kopp, S; Miyamoto, R

    2007-01-01

    Following successful experience at the BNL AGS, FNAL Tevatron, and CERN SPS, an AC Dipole will be adopted at the LHC for rapid measurements of ring optics. This paper describes some of the parameters of the AC dipole for the LHC, scaling from performance of the FNAL and BNL devices.

  20. Precursors of Short GRBs Registered by SPI-ACS/INTEGRAL

    Science.gov (United States)

    Minaev, P.; Pozanenko, A.

    2016-10-01

    We have searched for precursors in light curves of short gamma-ray bursts registered by SPI-ACS/INTEGRAL in 2002-2014. The portion of short bursts with precursor activity will be less than 0.4% from all short bursts registered by SPI-ACS.

  1. Scaling and universality of ac conduction in disordered solids

    DEFF Research Database (Denmark)

    Schrøder, Thomas; Dyre, Jeppe

    2000-01-01

    Recent scaling results for the ac conductivity of ionic glasses by Roling et al. [Phys. Rev. Lett. 78, 2160 (1997)] and Sidebottom [Phys. Rev. Lett. 82, 3653 (1999)] are discussed. We prove that Sidebottom's version of scaling is completely general. A new approximation to the universal ac...

  2. The topological AC effect on noncommutative phase space

    CERN Document Server

    Li, K; Li, Kang; Wang, Jianhua

    2006-01-01

    The Aharonov-Casher (AC) effect in non-commutative(NC) quantum mechanics is studied. Instead of using the star product method, we use a generalization of Bopp's shift method. After solving the Dirac equations both on noncommutative space and noncommutative phase space by the new method, we obtain the corrections to AC phase on NC space and NC phase space respectively.

  3. Operation of AC Adapters Visualized Using Light-Emitting Diodes

    Science.gov (United States)

    Regester, Jeffrey

    2016-01-01

    A bridge rectifier is a diamond-shaped configuration of diodes that serves to convert alternating current(AC) into direct current (DC). In our world of AC outlets and DC electronics, they are ubiquitous. Of course, most bridge rectifiers are built with regular diodes, not the light-emitting variety, because LEDs have a number of disadvantages. For…

  4. New switching pattern for AC/AC converters with RB-IGBTs for offshore wind parks

    OpenAIRE

    Mogstad, Anne Berit

    2008-01-01

    Offshore wind power has an increasing interest in the research community and among the politicians. Therefore it is important to find the right solutions to meet the environmental and commercial requirements to give offshore wind power a promising future. This thesis are proposing a new converter topology for offshore wind parks. Since the topology is based on DC transmission in stead of AC transmission it is better suited for use in this type of parks. All the converters are located in the w...

  5. HVDC-AC system interaction from AC harmonics. Volume 1. Harmonic impedance calculations. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Breuer, G D; Chow, J H; Lindh, C B; Miller, N W; Numrich, F H; Price, W W; Turner, A E; Whitney, R R

    1982-09-01

    Improved methods are needed to characterize ac system harmonic behavior for ac filter design for HVDC systems. The purpose of this General Electric Company RP1138 research is to evaluate the present filter design practice and to investigate methods for calculating system harmonic impedances. An overview of ac filter design for HVDC systems and a survey of literature related to filter design have been performed. Two methods for calculating system harmonic impedances have been investigated. In the measurement method, an instrumentation system for measuring system voltage and current has been assembled. Different schemes of using the measurements to calculate system harmonic impedances have been studied. In the analytical method, a procedure to include various operating conditions has been proposed. Computer programs for both methods have been prepared, and the results of the measurement and analytical methods analyzed. A conclusion of the project is that the measurement and analytical methods both provided reasonable results. There are correlations between the measured and analytical results for most harmonics, although there are discrepancies between the assumptions used in the two methods. A sensitivity approach has been proposed to further correlate the results. From the results of the analysis, it is recommended that both methods should be tested further. For the measurement method, more testing should be done to cover different system operating conditions. In the analytical method, more detailed models for representing system components should be studied. In addition, alternative statistical and sensitivity approaches should be attempted.

  6. HVDC-AC system interaction from AC harmonics. Volume 1. Harmonic impedance calculations. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Breuer, G D; Chow, J H; Lindh, C B; Miller, N W; Numrich, F H; Price, W W; Turner, A E; Whitney, R R

    1982-09-01

    Improved methods are needed to characterize ac system harmonic behavior for ac filter design for HVDC systems. The purpose of this General Electric Company RP1138 research is to evaluate the present filter design practice and to investigate methods for calculating system harmonic impedances. An overview of ac filter design for HVDC systems and a survey of literature related to filter design have been performed. Two methods for calculating system harmonic impedances have been investigated. In the measurement method, an instrumentation system for measuring system voltage and current has been assembled. Different schemes of using the measurements to calculate system harmonic impedances have been studied. In the analytical method, a procedure to include various operating conditions has been proposed. Computer programs for both methods have been prepared, and the results of the measurement and analytical methods analyzed. A conclusion of the project is that the measurement and analytical methods both provided reasonable results. There are correlations between the measured and analytical results for most harmonics, although there are discrepancies between the assumptions used in the two methods. A sensitivity approach has been proposed to further correlate the results. From the results of the analysis, it is recommended that both methods should be tested further. For the measurement method, more testing should be done to cover different system operating conditions. In the analytical method, more detailed models for representing system components should be studied. In addition, alternative statistical and sensitivity approaches should be attempted.

  7. Ac response of a coupled double quantum dot

    Institute of Scientific and Technical Information of China (English)

    Xu Jie; W.Z. Shangguan; Zhan Shi-Chang

    2005-01-01

    The effect of phase-breaking process on the ac response of a coupled double quantum dot is studied in this paper based on the nonequilibrium Green function formalism. A general expression is derived for the ac current in the presence of electron-phonon interaction. The ac conductance is numerically computed and the results are compared with those in [Anatram M P and Datts S 1995 Phys. Rev. B 51 7632]. Our results reveal that the inter-dot electron tunnelling interplays with that between dots and electron reservoirs, and contributes prominently to the ac current when inter-dot tunnelling coupling is much larger than the tunnelling coupling between dots and electron reservoirs. In addition, the phase-breaking process is found to have a significant effect on the ac transport through the coupled double dot.

  8. Characterisation of AC1: a naturally decaffeinated coffee

    Directory of Open Access Journals (Sweden)

    Luciana Benjamim Benatti

    2012-01-01

    Full Text Available We compared the biochemical characteristics of the beans of a naturally decaffeinated Arabica coffee (AC1 discovered in 2004 with those of the widely grown Brazilian Arabica cultivar "Mundo Novo" (MN. Although we observed differences during fruit development, the contents of amino acids, organic acids, chlorogenic acids, soluble sugars and trigonelline were similar in the ripe fruits of AC1 and MN. AC1 beans accumulated theobromine, and caffeine was almost entirely absent. Tests on the supply of [2-14C] adenine and enzymatic analysis of theobromine synthase and caffeine synthase in the endosperm of AC1 confirmed that, as in the leaves, caffeine synthesis is blocked during the methylation of theobromine to caffeine. The quality of the final coffee beverage obtained from AC1 was similar to that of MN.

  9. Determination for β-delayed fission probability of 230Ac

    Institute of Scientific and Technical Information of China (English)

    袁双贵; 杨维凡; 徐岩冰; 肖永厚; 罗亦孝

    2002-01-01

    The 230Ra has been produced via 232Th-2p reaction induced by 60 MeV/u 18O ion irradia-tion of natural thorium. The radium was radiochemically separated from the mixture of thorium andreaction products. Thin Ra sources in which 230Ac was got through 230Ra β- → 230Ac were pre-pared for observing fission fragments from β-delayed fission of 230Ac. The sources were exposedto the mica fission track detectors and measured by the HPGe γ detector. The precursor 230Ac wasidentified by means of observed two fission events as well as γ spectra, and the β-delayed fissionprobability of 230Ac was obtained to be (1.19±0.85) × 10-8.

  10. Estimation of the Thurstonian model for the 2-AC protocol

    DEFF Research Database (Denmark)

    Christensen, Rune Haubo Bojesen; Lee, Hye-Seong; Brockhoff, Per B.

    2012-01-01

    The 2-AC protocol is a 2-AFC protocol with a “no-difference” option and is technically identical to the paired preference test with a “no-preference” option. The Thurstonian model for the 2-AC protocol is parameterized by δ and a decision parameter τ, the estimates of which can be obtained...... by fairly simple well-known methods. In this paper we describe how standard errors of the parameters can be obtained and how exact power computations can be performed. We also show how the Thurstonian model for the 2-AC protocol is closely related to a statistical model known as a cumulative probit model....... This relationship makes it possible to extract estimates and standard errors of δ and τ from general statistical software, and furthermore, it makes it possible to combine standard regression modelling with the Thurstonian model for the 2-AC protocol. A model for replicated 2-AC data is proposed using cumulative...

  11. 单相电压型Z源AC/AC变流器电路%Single-Phase Voltage-Fed Z-Source AC/AC Converter

    Institute of Scientific and Technical Information of China (English)

    房绪鹏

    2006-01-01

    提出了一种新型AC/AC变流器电路--单相电压型Z源AC/AC变流器;介绍了其电路拓扑、工作原理、控制方法等;给出了相应的仿真和实验结果.仿真和实验证实了该电路拓扑的合理性和优越性.

  12. 40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

    Science.gov (United States)

    2010-07-01

    ... Procedures § 86.162-00 Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2. The alternative air conditioning test procedures AC1 and AC2 are approved by the Administrator... requirements of paragraph (a) of this section and meet the requirements of § 86.163-00. Air conditioning tests...

  13. An Ac transposon system based on maize chromosome 4S for isolating long-distance-transposed Ac tags in the maize genome.

    Science.gov (United States)

    Wang, Fei; Li, Zhaoying; Fan, Jun; Li, Pengfei; Hu, Wei; Wang, Gang; Xu, Zhengkai; Song, Rentao

    2010-12-01

    Transposon tagging is an important tool for gene isolation and functional studies. In maize, several transposon-tagging systems have been developed, mostly using Activator/Dissociation (Ac/Ds) and Mutator systems. Here, we establish another Ac-based transposon system with the donor Ac tightly linked with sugary1 (su1) on maize chromosome 4S. Newly transposed Ac (tr-Acs) were detected based on a negative dosage effect, and long-distance-transposed Ac events were identified and isolated from the donor Ac by a simple backcross scheme. In this study, we identified 208 independent long-distance-transposed Ac lines. Thirty-one flanking sequences of these tr-Acs were isolated and localized in the maize genome. As found in previous studies, the tr-Acs preferentially inserted into genic sequences. The distribution of tr-Acs is not random. In our study, the tr-Acs preferentially transposed into chromosomes 1, 2, 9 and 10. We discuss the preferential distribution of tr-Acs from Ac systems. Our system is complementary to two other Ac-based regional-mutagenesis systems in maize, and the combined use of these systems will achieve an even and high-density distribution of Ac elements throughout the maize genome for functional-genomics studies.

  14. Safe-commutation principle for direct single-phase AC-AC converters for use in audio power amplification

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2004-01-01

    This paper presents an alternative safe commutation principle for a single phase bidirectional bridge, for use in the new generation of direct single-stage AC-AC audio power amplifiers. As compared with the bridge commutation with load current or source voltage sensing, in this approach...

  15. Safe-commutation principle for direct single-phase AC-AC converters for use in audio power amplification

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2004-01-01

    This paper presents an alternative safe commutation principle for a single phase bidirectional bridge, for use in the new generation of direct single-stage AC-AC audio power amplifiers. As compared with the bridge commutation with load current or source voltage sensing, in this approach...

  16. The complete Ac/Ds transposon family of maize.

    Science.gov (United States)

    Du, Chunguang; Hoffman, Andrew; He, Limei; Caronna, Jason; Dooner, Hugo K

    2011-12-01

    The nonautonomous maize Ds transposons can only move in the presence of the autonomous element Ac. They comprise a heterogeneous group that share 11-bp terminal inverted repeats (TIRs) and some subterminal repeats, but vary greatly in size and composition. Three classes of Ds elements can cause mutations: Ds-del, internal deletions of the 4.6-kb Ac element; Ds1, ~400-bp in size and sharing little homology with Ac, and Ds2, variably-sized elements containing about 0.5 kb from the Ac termini and unrelated internal sequences. Here, we analyze the entire complement of Ds-related sequences in the genome of the inbred B73 and ask whether additional classes of Ds-like (Ds-l) elements, not uncovered genetically, are mobilized by Ac. We also compare the makeup of Ds-related sequences in two maize inbreds of different origin. We found 903 elements with 11-bp Ac/Ds TIRs flanked by 8-bp target site duplications. Three resemble Ac, but carry small rearrangements. The others are much shorter, once extraneous insertions are removed. There are 331 Ds1 and 39 Ds2 elements, many of which are likely mobilized by Ac, and two novel classes of Ds-l elements. Ds-l3 elements lack subterminal homology with Ac, but carry transposase gene fragments, and represent decaying Ac elements. There are 44 such elements in B73. Ds-l4 elements share little similarity with Ac outside of the 11-bp TIR, have a modal length of ~1 kb, and carry filler DNA which, in a few cases, could be matched to gene fragments. Most Ds-related elements in B73 (486/903) fall in this class. None of the Ds-l elements tested responded to Ac. Only half of Ds insertion sites examined are shared between the inbreds B73 and W22. The majority of Ds-related sequences in maize correspond to Ds-l elements that do not transpose in the presence of Ac. Unlike actively transposing elements, many Ds-l elements are inserted in repetitive DNA, where they probably become methylated and begin to decay. The filler DNA present in most elements

  17. Measurement of AC loss of superconductors by vaporizing method

    Energy Technology Data Exchange (ETDEWEB)

    Wakabayashi, Hiroshi; Isono, Takaaki; Matsui, Kunihiro; Fujisaki, Reishi; Nunoya, Yoshihiko; Koizumi, Norikiyo; Takahashi, Yoshikazu; Tsuji, Hiroshi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    1995-07-01

    In Japan Atomic Energy Research Institute, the development of superconducting pulse conductors for next period nuclear fusion reactors has been carried out. For these conductors, the rated current of 46 kA and the rated magnetic field of 13T are demanded. When the pulse excitation of superconductors is carried out, AC loss arises, and the temperature of the superconductors rises, and when it exceeds a certain value, the superconducting state cannot be maintained. Therefore, the AC loss of pulse conductors must be limited to a low value. It is difficult to evaluate the AC loss of superconductors by calculation, therefore, it is evaluated by actual measurement. There are magnetizing method and vaporizing method for measuring the AC loss. This time, the equipment for measuring the AC loss of 40 kA class superconductors by vaporizing method which measures the helium gas quantity vaporizing at the time of AC loss occurrence was designed and manufactured for the first time. The method of measuring the AC loss, the structure of the measuring equipment, the helium gas recovering part and the measuring part, the countermeasures for preventing helium gas leakage, the resistance heater for calibration, and the results of measurement are reported. (K.I.)

  18. Faint Galaxies in deep ACS observations

    CERN Document Server

    Benítez, N; Bouwens, R; Menanteau, F; Blakeslee, J P; Gronwall, C; Illingworth, G D; Meurer, G; Broadhurst, T J; Clampin, M; Franx, M; Hartig, G F; Magee, D; Sirianni, M; Ardila, D R; Bartko, F; Brown, R A; Burrows, C J; Cheng, E S; Cross, N J G; Feldman, P D; Golimowski, D A; Infante, L; Kimble, R A; Krist, J E; Lesser, M P; Levay, Z G; Martel, A R; Miley, G K; Postman, M; Rosati, P; Sparks, W B; Tran, H D; Tsvetanov, Z I; Zheng, R L

    2003-01-01

    We present the analysis of the faint galaxy population in the Advanced Camera for Surveys (ACS) Early Release Observation fields VV 29 (UGC 10214) and NGC 4676. Here we attempt to thoroughly consider all aspects relevant for faint galaxy counting and photometry, developing methods which are based on public software and that are easily reproducible by other astronomers. Using simulations we determine the best SExtractor parameters for the detection of faint galaxies in deep HST observations, paying special attention to the issue of deblending, which significantly affects the normalization and shape of the number count distribution. We confirm, as claimed by Bernstein, Freedman and Madore (2002), that Kron-like magnitudes, such as the ones generated by SExtractor, can miss more than half of the light of faint galaxies, what dramatically affects the slope of the number counts. We present catalogs for the VV 29 and NGC 4676 fields with photometry in the g,V and I bands. We also show that combining the bayesian so...

  19. AC Impedance Behaviour of Black Diamond Films

    Institute of Scientific and Technical Information of China (English)

    Haitao YE; Olivier GAUDIN; Richard B.JACKMAN

    2005-01-01

    The first measurement of impedance on free-standing diamond films from 0.1 Hz to 10 MHz up to 300℃ were reported. A wide range of chemical vapour deposition (CVD) materials were investigated, but here we concentrate are well fitted to a RC parallel circuit model and the equivalent resistance and capacitance for the diamond films have been estimated using the Zview curve fitting. The results show only one single semicircle response at each temperature measured. It was found that the resistance decreases from 62 MΩ at room temperature to 4 kΩ at300℃, with an activation energy around 0.51 eV. The equivalent capacitance is maintained at the level of 100 pF up to 300℃ suggesting that the diamond grain boundaries are dominating the conduction. At 400℃, the impedance at low frequencies shows a linear tail, which can be explained that the AC polarization of diamond/Au interface occurs.

  20. Neurinoma central do nervo acústico

    Directory of Open Access Journals (Sweden)

    Paulo Pinto Pupo

    1950-03-01

    Full Text Available O autor apresenta o caso de uma paciente com 45 anos, com hipertensão arterial, queixando-se de tonturas e surdez progressiva à esquerda que, ao exame neurológico, apresentava síndrome protuberancial, com hemi-anestesia táctil e dolorosa à direita respeitando a face, hemiparesia direita, ataxia de tipo sensitivo nos membros da direita, paralisia facial de tipo periférico, hipoacusia, paresia de motor ocular externo à esquerda, síndrome vertiginosa e nistagmo horizontal ao olhar para a direita. À necrópsia foi encontrado um tumor na hemicalota protuberancial esquerda e foco malácico adjacente, secundário a distúrbio circulatório. O tumor, intimamente dependente das raízes intraprotuberanciais do nervo acústico, se apresentava com as características histológicas dos neurinomas. Além dessas particularidades, a lesão do feixe central da calota e conseqüente degeneração "hipertrófica" da oliva bulbar constituem outro aspecto de grande interêsse dêste caso.

  1. Analysis of Input and Output Ripples of PWM AC Choppers

    Directory of Open Access Journals (Sweden)

    Pekik Argo Dahono

    2008-11-01

    Full Text Available This paper presents an analysis of input and output ripples of PWM AC choppers. Expressions of input and output current and voltage ripples of single-phase PWM AC choppers are first derived. The derived expressions are then extended to three-phase PWM AC choppers. As input current and output voltage ripples specification alone cannot be used to determine the unique values of inductance and capacitance of the LC filters, an additional criterion based on the minimum reactive power is proposed. Experimental results are included in this paper to show the validity of the proposed analysis method.

  2. Recurrent Security Gaps In 802.11ac Routers

    OpenAIRE

    Mohammed Farik; ABM Shawkat Ali

    2015-01-01

    Abstract In comparison to earlier IEEE 802.11 standard abgn routers todays popular 802.11ac standard routers have enhanced security. However 802.11ac router still has major security vulnerabilities. The novelty of this paper is that we not only highlight multiple security vulnerabilities in 802.11ac router technologies that still have not been secured since the earlier standards but also present some new ideas with solutions. We believe that our line of thoughts on security vulnerabilities ga...

  3. An Improved AC-BM Algorithm for Monitoring Watch List

    Directory of Open Access Journals (Sweden)

    Mo Yiwen

    2013-07-01

    Full Text Available With the expanding of database of the watch list of anti-money laundering, improving the speed in matching between the watch list and the database of account holders and clients’ transaction is especially important. This paper proposes an improved AC-BM Algorithm, a matching algorithm of subsection, to improve the speed of matching. Experiment results show the time performance of the improved algorithm is better than traditional BM algorithm, AC algorithm and the AC-BM algorithm. It can improve the efficiency of on-line monitoring of anti-money laundering.  

  4. Cyclotron production of Ac-225 for targeted alpha therapy.

    Science.gov (United States)

    Apostolidis, C; Molinet, R; McGinley, J; Abbas, K; Möllenbeck, J; Morgenstern, A

    2005-03-01

    The feasibility of producing Ac-225 by proton irradiation of Ra-226 in a cyclotron through the reaction Ra-226(p,2n)Ac-225 has been experimentally demonstrated for the first time. Proton energies were varied from 8.8 to 24.8 MeV and cross-sections were determined by radiochemical analysis of reaction yields. Maximum yields were reached at incident proton energies of 16.8 MeV. Radiochemical separation of Ac-225 from the irradiated target yielded a product suitable for targeted alpha therapy of cancer.

  5. Advanced DC/AC inverters applications in renewable energy

    CERN Document Server

    Luo, Fang Lin

    2013-01-01

    DC/AC inversion technology is of vital importance for industrial applications, including electrical vehicles and renewable energy systems, which require a large number of inverters. In recent years, inversion technology has developed rapidly, with new topologies improving the power factor and increasing power efficiency. Proposing many novel approaches, Advanced DC/AC Inverters: Applications in Renewable Energy describes advanced DC/AC inverters that can be used for renewable energy systems. The book introduces more than 100 topologies of advanced inverters originally developed by the authors,

  6. Single-Phase Four Switch Z-Source AC-AC Converters%单相四开关Z源AC-AC变换器

    Institute of Scientific and Technical Information of China (English)

    汤雨; 谢少军; 张超华

    2007-01-01

    提出了一种单相四开关Z源AC-AC变换器,它包括电压型与电流型两类.与传统脉宽调制AC-AC变换器相比,它具有如下特点:输出电压范围宽且可升可降,输出电压与输入电压可同相或反相,冲击和谐波电流小,可靠性高.针对AC-AC变换器中固有的开关管换流问题,提出了一种适用于单相四开关Z源AC-AC变换器的换流方案,无需外加缓冲吸收电路即可实现开关管的安全换流.以电压型单相四开关Z源AC-AC变换器为例,对其进行了理论分析、仿真和原理试验研究.实验结果证实了Z源变换器的特性及换流方案的可行性.

  7. ACS Algorithm in Discrete Ordinates for Pressure Vessel Dosimetry

    Directory of Open Access Journals (Sweden)

    Walters William

    2016-01-01

    Full Text Available The Adaptive Collision Source (ACS method can solve the Linear Boltzmann Equation (LBE more efficiently by adaptation of the angular quadrature order. This is similar to, and essentially an extension of, the first collision source method. Previously, the ACS methodology has been implemented into the TITAN discrete ordinates code, and has shown speedups of 2–4 on a simple test problem, with very little loss of accuracy (within a provided adaptive tolerance. This work examines the use of the ACS method for a more realistic problem: pressure vessel dosimetry with the VENUS-2 MOX-fuelled reactor dosimetry benchmark. The ACS method proved to be able to obtain accurate results while being approximately twice as efficient as using a constant quadrature in a standard source iteration scheme.

  8. Fabrication of alumina films with laminated structures by ac anodization

    Directory of Open Access Journals (Sweden)

    Hiroyo Segawa

    2014-01-01

    Full Text Available Anodization techniques by alternating current (ac are introduced in this review. By using ac anodization, laminated alumina films are fabricated. Different types of alumina films consisting of 50–200 nm layers were obtained by varying both the ac power supply and the electrolyte. The total film thickness increased with an increase in the total charge transferred. The thickness of the individual layers increased with the ac voltage; however, the anodization time had little effect on the film thickness. The laminated alumina films resembled the nacre structure of shells, and the different morphologies exhibited by bivalves and spiral shells could be replicated by controlling the rate of increase of the applied potentials.

  9. A hybrid electromechanical solid state switch for ac power control

    Science.gov (United States)

    1972-01-01

    Bidirectional thyristor coupled to a series of actuator driven electromechanical contacts generates hybrid electromechanical solid state switch for ac power control. Device is useful in power control applications where zero crossover switching is required.

  10. EHV AC undergrounding electrical power performance and planning

    CERN Document Server

    Benato, Roberto

    2014-01-01

    Analytical methods of cable performance in EHV AC electrical power are discussed in this comprehensive reference. Descriptions of energization, power quality, cable safety constraints and more, guide readers in cable planning and power network operations.

  11. Hydrolysis of polycarbonate catalyzed by ionic liquid [Bmim][Ac].

    Science.gov (United States)

    Song, Xiuyan; Liu, Fusheng; Li, Lei; Yang, Xuequn; Yu, Shitao; Ge, Xiaoping

    2013-01-15

    Hydrolysis of polycarbonate (PC) was studied using ionic liquid 1-butyl-3-methylimidazolium acetate ([Bmim][Ac]) as a catalyst. The influences of temperature, time, water dosage and [Bmim][Ac] dosage on the hydrolysis reaction were examined. Under the conditions of temperature 140°C, reaction time 3.0 h, m([Bmim][Ac]):m(PC)=1.5:1 and m(H(2)O):m(PC)=0.35:1, the conversion of PC was nearly 100% and the yield of bisphenol A (BPA) was over 96%. The ionic liquid could be reused up to 6 times without apparent decrease in the conversion of PC and yield of BPA. The kinetics of the reaction was also investigated. The results showed that the hydrolysis of PC in [Bmim][Ac] was a first-order kinetic reaction with an activation energy of 228 kJ/mol.

  12. Methanolysis of polycarbonate catalysed by ionic liquid [Bmim][Ac].

    Science.gov (United States)

    Liu, Fusheng; Li, Lei; Yu, Shitao; Lv, Zhiguo; Ge, Xiaoping

    2011-05-15

    The methanolysis of polycarbonate (PC) was studied using ionic liquid [Bmim][Ac] as a catalyst. The effects of temperature, time, methanol dosage and [Bmim][Ac] dosage on the methanolysis reaction were examined. It was shown that the conversion of PC was nearly 100%, and the yield of bisphenol A (BPA) was over 95% under the following conditions: m([Bmim][Ac]):m(PC) = 0.75:1;m(methanol):m(PC) = 0.75:1; a reaction temperature of 90 °C and a total time of 2.5h. The ionic liquid could be reused up to 6 times with no apparent decrease in the conversion of PC and yield of BPA. The kinetics of the reaction was also investigated. The results indicated that the methanolysis of PC in [Bmim][Ac] was a first-order kinetic reaction with an activation energy of 167 kJ/mol.

  13. PREVENTION AND CONTROL OF TUBERCULOSIS *A.C. Okoh ...

    African Journals Online (AJOL)

    drclement

    *A.C. Okoh. Department of Community Health, University of Teaching Hospital Benin City,. Nigeria ... Organization. (WHO) ... Control is the reduction of the prevalence ... behavioural changes, especially in ... stimulate an acquired resistance to.

  14. Alternating current(AC) corrosion analyzed by electrochemical impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Tae Hyun; Kim, Dae Kyeong; Bae, Jeong Hyo; Lee, Hyun Goo; Lee, Sung Jin [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

    2002-12-15

    So far, many research results on AC corrosion have been reported but each one is not consistent with another. In order to understand the characteristics and factors affecting on AC corrosion, Electrochemical impedance spectroscopy (E.I.S) was used and changes in kinetics and surface properties was analyzed. Generally, E.I.S. test has been used mainly for the diagnosis of the concrete corrosion and coating material. However, considering the outstanding functions of E.I.S. test, it can be adopted as a good method to study AC corrosion. Electrolyte resistance (R{sub sol}), double layer capacitance (C{sub dl}) and polarization resistance (R{sub p}) are the basic circuit elements. Using the model which is consist of these basic elements, various results of E.I.S. test can be interpreted. And through this method the mechanism and characteristics of AC corrosion can be explained

  15. American Community Survey (ACS) 5-Year Estimates for Coastal Geographies

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The American Community Survey (ACS) is an ongoing statistical survey that samples a small percentage of the population every year. These data have been apportioned...

  16. A precursor of β-delayed fission:230Ac

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The 230Ra has been produced via multinucleon transfer and dissipativefragmentation of heavy target in the 60 MeV/u 18O ion reaction with natural thorium.The radium was radiochemically separated from irradiated thorium targets. 230Acwas obtained by 230Ra β-→ 230Ac. Thin Ra sources were prepared for observing fissionfragments from β-delayed fission of 230Ac. The sources were exposed to the micafission track detectors and measured by a HPGe γ detector. The two fission eventswere obtained and could been assigned to theβ-delayed fission of 230Ac. The β-delayedfission probability of 230Ac was determined to be (1.19+0.85) × 10-8.

  17. A Switched Capacitor Based AC/DC Resonant Converter for High Frequency AC Power Generation

    Directory of Open Access Journals (Sweden)

    Cuidong Xu

    2015-09-01

    Full Text Available A switched capacitor based AC-DC resonant power converter is proposed for high frequency power generation output conversion. This converter is suitable for small scale, high frequency wind power generation. It has a high conversion ratio to provide a step down from high voltage to low voltage for easy use. The voltage conversion ratio of conventional switched capacitor power converters is fixed to n, 1/n or −1/n (n is the switched capacitor cell. In this paper, A circuit which can provide n, 1/n and 2n/m of the voltage conversion ratio is presented (n is stepping up the switched capacitor cell, m is stepping down the switching capacitor cell. The conversion ratio can be changed greatly by using only two switches. A resonant tank is used to assist in zero current switching, and hence the current spike, which usually exists in a classical switching switched capacitor converter, can be eliminated. Both easy operation and efficiency are possible. Principles of operation, computer simulations and experimental results of the proposed circuit are presented. General analysis and design methods are given. The experimental result verifies the theoretical analysis of high frequency AC power generation.

  18. Simulation of the Relaxation Potential Profile of an ac-dc-ac Test

    Directory of Open Access Journals (Sweden)

    Kerry N. Allahar

    2014-01-01

    Full Text Available The relaxation period of the accelerated ac-dc-ac test for coatings is associated with the transient electrochemistry that occurs when the immersed coated system is allowed to return to a stable open-circuit condition after being subjected to a cathodic potential. A mathematical model of the transient electrochemistry that occurs during this relaxation period is presented for coated aluminum. Expressions for the corrosion potential and corrosion current as functions of the local pH at the metal-coating interface were developed using reported experimental results. These expressions enabled the simulation of the transient electrochemistry under the constraint of balanced anodic and cathodic current densities. Regression of the transient relaxation potential profiles to exponential decay functions provided time-constant characterization of the profiles. Simulated results are presented that demonstrate the influences of the coating's porosity and thickness, the applied dc potential and the metal-coating interface condition on the time-constants associated with the relaxation profile. Interpretation of experimentally reported relaxation potential profiles supported the analysis of the simulated results.

  19. Diffusive Suppression of AC-Stark Shifts in Atomic Magnetometers

    CERN Document Server

    Sulai, I A; Kauer, M; Smetana, G S; Wakai, R T; Walker, T G

    2012-01-01

    In atomic magnetometers, the vector AC-Stark shift associated with circularly polarized light generates spatially varying effective magnetic fields which limit the magnetometer response and serve as sources of noise. We describe a scheme whereby optically pumping a small sub-volume of the magnetometer cell and relying on diffusion to transport polarized atoms allows a magnetometer to be operated with minimal sensitivity to the AC-Stark field.

  20. Antifriction coatings based on a-C for biomedicine applications

    Science.gov (United States)

    Yurjev, Y. N.; Kiseleva, D. V.; Zaitcev, D. A.; Sidelev, D. V.; Korneva, O. S.

    2016-01-01

    This article reports on the investigation of mechanical properties of carbon films deposited by dual magnetron sputtering system with closed and mirror magnetic field. There is shown that a-C films with predominantly sp2-phase have relatively high hardness (up to 20 GPa) and low friction index (∼0.01). The influence of magnetic field on friction index is determined. The analysis of experimental data shows the obtained a-C samples can be used for biomedicine applications.

  1. Adiabaticity of the ramping process of an ac dipole

    Directory of Open Access Journals (Sweden)

    R. Tomás

    2005-02-01

    Full Text Available ac dipoles in accelerators are used to excite coherent betatron oscillations at a drive frequency close to the tune. If the excitation amplitude is slowly increased to the desired value and slowly decreased back to zero there is no significant emittance growth. The aim of this article is to study the adiabaticity of the ramping process of an ac dipole as a function of the different parameters involved.

  2. Development of the Field of Flexible AC Transmission Systems (FACTS)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@ Theoretical and technological development of large capacity power electronics and flexible AC transmission systems are one of the most important projects developed by Tsinghua University. The Flexible AC Transmission System (FACTS) technology which uses power electronics to improve the efficiency and quality of the electrical generation, transmission and distribution system is considered to be one of the most significant technological innovations for power systems in the 20th century. The advanced static var generator (ASVG) is a key FACTS device.

  3. An AC magnetohydrodynamic micropump: towards a true integrated microfluidic system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A P; Lemoff, A V; McConaghy, C F; Miles, R R

    1999-03-01

    An AC Magnetohydrodynamic (MHD) micropump has been demonstrated in which the Lorentz force is used to propel an electrolytic solution along a microchannel etched in silicon. This micropump has no moving parts, produces a continuous (not pulsatile) flow, and is compatible with solutions containing biological specimens. micropump, using the Lorentz force as the pumping mechanism for biological analysis. The AC Magnetohydrodynamic (MHD) micropump investigated produces a continuous flow and allows for complex microchannel design.

  4. The topological AC effect on non-commutative phase space

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kang [Hangzhou Teachers College, Department of Physics, Hangzhou (China); The Abdus Salam International Center for Theoretical Physics, Trieste (Italy); Wang, Jianhua [Shaanxi University of Technology, Department of Physics, Hanzhong (China); The Abdus Salam International Center for Theoretical Physics, Trieste (Italy)

    2007-05-15

    The Aharonov-Casher (AC) effect in non-commutative (NC) quantum mechanics is studied. Instead of using the star product method, we use a generalization of Bopp's shift method. After solving the Dirac equations both on non-commutative space and non-commutative phase space by the new method, we obtain corrections to the AC phase on NC space and NC phase space, respectively. (orig.)

  5. Diagnostics of the Fermilab Tevatron using an AC dipole

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Ryoichi [Univ. of Texas, Austin, TX (United States)

    2008-08-01

    The Fermilab Tevatron is currently the world's highest energy colliding beam facility. Its counter-rotating proton and antiproton beams collide at 2 TeV center-of-mass. Delivery of such intense beam fluxes to experiments has required improved knowledge of the Tevatron's beam optical lattice. An oscillating dipole magnet, referred to as an AC dipole, is one of such a tool to non-destructively assess the optical properties of the synchrotron. We discusses development of an AC dipole system for the Tevatron, a fast-oscillating (f ~ 20 kHz) dipole magnet which can be adiabatically turned on and off to establish sustained coherent oscillations of the beam particles without affecting the transverse emittance. By utilizing an existing magnet and a higher power audio amplifier, the cost of the Tevatron AC dipole system became relatively inexpensive. We discuss corrections which must be applied to the driven oscillation measurements to obtain the proper interpretation of beam optical parameters from AC dipole studies. After successful operations of the Tevatron AC dipole system, AC dipole systems, similar to that in the Tevatron, will be build for the CERN LHC. We present several measurements of linear optical parameters (beta function and phase advance) for the Tevatron, as well as studies of non-linear perturbations from sextupole and octupole elements.

  6. Role of nuclear Lamin A/C in cardiomyocyte functions.

    Science.gov (United States)

    Carmosino, Monica; Torretta, Silvia; Procino, Giuseppe; Gerbino, Andrea; Forleo, Cinzia; Favale, Stefano; Svelto, Maria

    2014-10-01

    Lamin A/C is a structural protein of the nuclear envelope (NE) and cardiac involvement in Lamin A/C mutations was one of the first phenotypes to be reported in humans, suggesting a crucial role of this protein in the cardiomyocytes function. Mutations in LMNA gene cause a class of pathologies generically named 'Lamanopathies' mainly involving heart and skeletal muscles. Moreover, the well-known disease called Hutchinson-Gilford Progeria Syndrome due to extensive mutations in LMNA gene, in addition to the systemic phenotype of premature aging, is characterised by the death of patients at around 13 typically for a heart attack or stroke, suggesting again the heart as the main site sensitive to Lamin A/C disfunction. Indeed, the identification of the roles of the Lamin A/C in cardiomyocytes function is a key area of exploration. One of the primary biological roles recently conferred to Lamin A/C is to affect contractile cells lineage determination and senescence. Then, in differentiated adult cardiomyocytes both the 'structural' and 'gene expression hypothesis' could explain the role of Lamin A in the function of cardiomyocytes. In fact, recent advances in the field propose that the structural weakness/stiffness of the NE, regulated by Lamin A/C amount in NE, can 'consequently' alter gene expression. © 2014 Société Française des Microscopies and Société de Biologie Cellulaire de France. Published by John Wiley & Sons Ltd.

  7. AC electrophoretic deposition of organic-inorganic composite coatings.

    Science.gov (United States)

    Yoshioka, T; Chávez-Valdez, A; Roether, J A; Schubert, D W; Boccaccini, A R

    2013-02-15

    Alternating current electrophoretic deposition (AC-EPD) of polyacrylic acid (PAA)-titanium oxide (TiO(2)) nanoparticle composites on stainless steel electrodes was investigated in basic aqueous solution. AC square wave with duty cycle of 80% was applied at a frequency of 1 kHz. FTIR-ATR spectra showed that both AC and direct current (DC) EPD successfully deposited PAA-TiO(2) composites. The deposition rate using AC-EPD was lower than that obtained in direct current DC-EPD. However, the microstructure and surface morphology of the deposited composite coatings were different depending on the type of electric field applied. AC-EPD applied for not more than 5 min led to smooth films without bubble formation, while DC-EPD for 1 min or more showed deposits with microstructural defects possibly as result of water electrolysis. AC-EPD was thus for the first time demonstrated to be a suitable technique to deposit organic-inorganic composite coatings from aqueous suspensions, showing that applying a square wave and frequency of 1 kHz leads to uniform PAA-TiO(2) composite coatings on conductive materials.

  8. A Novel High Performance Bridgeless Ac-Dc Boost Converter

    Directory of Open Access Journals (Sweden)

    S.M.AshrafulAlam Mohon

    2016-08-01

    Full Text Available A new single phase high performance bridgeless AC-DC Boost converter is proposed. The converter is made bridgeless by the use of two unidirectional switches and two diodes at the input ac side for power conversion for both positive and negative half cycle. Because of the high frequency switching, the power factor of the circuit is inherently corrected and it requires a small filter to make the input current near sinusoidal with limited THD. The significant improvement in THD makes the circuit a good choice in applications needing AC-DC conversion with power conditioning. The circuit exhibits such better performances than conventional AC-DC boost converter with variable loads at constant frequency switching with no additional control circuits. The efficiency of the circuit is also satisfactory. Analysis and simulation results of the circuit are obtained by using software simulation. The main advantage of this new AC-DC converter is its superior power quality over conventional AC-DC boost converter

  9. Update on bedside ultrasound (US) diagnosis of acute cholecystitis (AC).

    Science.gov (United States)

    Zenobii, Maria Francesca; Accogli, Esterita; Domanico, Andrea; Arienti, Vincenzo

    2016-03-01

    Acute cholecystitis (AC) represents a principal cause of morbidity worldwide and is one of the most frequent reasons for hospitalization due to gastroenteric tract diseases. AC should be suspected in presence of clinical signs and of gallstones on an imaging study. Upper abdominal US represents the first diagnostic imaging step in the case of suspected AC. Computed tomography (CT) with intravenous contrast (IV) or magnetic resonance imaging (MRI) with gadolinium contrast and technetium hepatobiliary iminodiacetic acid (Tc-HIDA) can be employed to exclude complications. US examination should be performed with right subcostal oblique, with longitudinal and intercostal scans. Normal gallbladder US findings and AC major and minor US signs are described. Polyps, sludge and gallbladder wall thickening represent the more frequent pitfalls and they must be differentiated from stones, duodenal artifacts and many other non-inflammatory conditions that cause wall thickening, respectively. By means of bedside ultrasound, the finding of gallstones in combination with acute pain, when the clinician presses the gallbladder with the US probe (the sonographic Murphy's sign), has a 92.2 % positive predictive value for AC. In our preliminary experience, bedside US-performed by echoscopy (ES) and/or point-of-care US (POCUS) demonstrated good reliability in detecting signs of AC, and was always integrated with physical examination and performed by a skilled operator.

  10. Temperature integration at the AC thermosensory neurons in Drosophila.

    Science.gov (United States)

    Tang, Xin; Platt, Michael D; Lagnese, Christopher M; Leslie, Jennifer R; Hamada, Fumika N

    2013-01-16

    Temperature sensation has a strong impact on animal behavior and is necessary for animals to avoid exposure to harmful temperatures. It is now well known that thermoTRP (transient receptor potential) channels in thermosensory neurons detect a variable range of temperature stimuli. However, little is known about how a range of temperature information is relayed and integrated in the neural circuits. Here, we show novel temperature integration between two warm inputs via Drosophila TRPA channels, TRPA1 and Pyrexia (Pyx). The internal AC (anterior cell) thermosensory neurons, which express TRPA1, detect warm temperatures and mediate temperature preference behavior. We found that the AC neurons were activated twice when subjected to increasing temperatures. The first response was at ∼25°C via TRPA1 channel, which is expressed in the AC neurons. The second response was at ∼27°C via the second antennal segments, indicating that the second antennal segments are involved in the detection of warm temperatures. Further analysis reveals that pyx-Gal4-expressing neurons have synapses on the AC neurons and that mutation of pyx eliminates the second response of the AC neurons. These data suggest that AC neurons integrate both their own TRPA1-dependent temperature responses and a Pyx-dependent temperature response from the second antennal segments. Our data reveal the first identification of temperature integration, which combines warm temperature information from peripheral to central neurons and provides the possibility that temperature integration is involved in the plasticity of behavioral outputs.

  11. Importance of Attenuation Correction (AC) for Small Animal PET Imaging

    DEFF Research Database (Denmark)

    El Ali, Henrik H.; Bodholdt, Rasmus Poul; Jørgensen, Jesper Tranekjær

    2012-01-01

    was performed. Methods: Ten NMRI nude mice with subcutaneous implantation of human breast cancer cells (MCF-7) were scanned consecutively in small animal PET and CT scanners (MicroPETTM Focus 120 and ImTek’s MicroCATTM II). CT-based AC, PET-based AC and uniform AC methods were compared. Results: The activity...... concentration in the same organ with and without AC revealed an overall attenuation recovery of 9–21% for MAP reconstructed images, i.e., SUV without AC could underestimate the true activity at this level. For subcutaneous tumors, the attenuation was 13 ± 4% (9–17%), for kidneys 20 ± 1% (19......–21%), and for bladder 18 ± 3% (15–21%). The FBP reconstructed images showed almost the same attenuation levels as the MAP reconstructed images for all organs. Conclusions: The annihilation photons are suffering attenuation even in small subjects. Both PET-based and CT-based are adequate as AC methods. The amplitude...

  12. 21 CFR 880.6320 - AC-powered medical examination light.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered medical examination light. 880.6320... Miscellaneous Devices § 880.6320 AC-powered medical examination light. (a) Identification. An AC-powered medical examination light is an AC-powered device intended for medical purposes that is used to illuminate...

  13. Monoclonal antibodies AC-43 and AC-29 disrupt Plasmodium vivax development in the Indian malaria vector Anopheles culicifacies (Diptera: culicidae)

    Indian Academy of Sciences (India)

    Manoj Chugh; B R Gulati; S K Gakhar

    2010-03-01

    A repertoire of monoclonal antibodies (mAbs) was generated against the midgut proteins of Anopheles culicifacies mosquitoes. The mAbs AC-43 and AC-29 significantly inhibited Plasmodium vivax development inside the mosquito midgut. The number of oocysts that developed was reduced by 78.6% when mosquitoes ingested a combination of these two mAbs along with the blood meal. AC-43 mAb binds to the epitope common in 97, 80 and 43 kDa polypeptides from the midgut protein extract, as indicated by western blot analysis. Similarly, the mAb AC-29 recognized 52, 44, 40 and 29 kDa polypeptides. These female midgut-specific polypeptides are shared between An. culicifacies and An. stephensi, two major vectors of malaria in India. Deglycosylation assays revealed that -linked carbohydrates are the major components in epitopes corresponding to AC-43 and AC-29. Gold particle labelling revealed that both these mAbs preferentially bind to glycoproteins at the apical microvilli and the microvillus-associated network present inside transverse sections of the gut epithelium. These regions are particularly known to have receptors for ookinetes, which enable them to cross this epithelial barrier and provide them with certain necessary chemicals or components for further development into oocysts. Therefore, these glycoproteins appear to be potential candidates for a vectordirected transmission-blocking vaccine (TBV).

  14. An AC/AC Direct Power Conversion Topology Having Multiple Power Grid Connections with Adjustable Loading

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2004-01-01

    Normally, a power converter has one supply port to connect to the power grid and one or multiple output ports to connect to AC loads that require variable voltage and variable frequency. As the trend on the energy market is towards deregulation, new converter topologies are needed to allow...... independent producers/consumers to connect to multiple distribution grids in order to optimise the electricity price, as this will vary during the day from one power distribution company to another one. It will be needed to have a load that can smoothly adjust the power consumed from each power grid in order...... these fraction power will be a necessary feature on a deregulated energy market. This paper presents a new topology of a power converter based on the Direct Power Conversion concept, which is able to connect to multiple grids and provide complete decoupling between without circulating power between the grids...

  15. Temas de Física para Ingeniería: Acústica

    OpenAIRE

    Beléndez Vázquez, Augusto

    1992-01-01

    Acústica, fluidos y termodinámica: "Acústica". Ondas sonoras, propagación. Sonidos puros, sonidos complejos y ruidos. Velocidad de propagación del sonido. Intensidad del sonido y potencia acústica. Impedancia acústica y transmisión del sonido. Medición del campo acústico: niveles. Audición. Interferencia de ondas sonoras y pulsaciones. Tubos sonoros. Efecto Doppler.

  16. Temas de Física para Ingeniería: Acústica

    OpenAIRE

    Beléndez Vázquez, Augusto

    1992-01-01

    Acústica, fluidos y termodinámica: "Acústica". Ondas sonoras, propagación. Sonidos puros, sonidos complejos y ruidos. Velocidad de propagación del sonido. Intensidad del sonido y potencia acústica. Impedancia acústica y transmisión del sonido. Medición del campo acústico: niveles. Audición. Interferencia de ondas sonoras y pulsaciones. Tubos sonoros. Efecto Doppler.

  17. 一种简单新型拓扑Cuk AC/AC变换器及其仿真研究%A New Simple Topology of Cuk AC/AC Converter and Its Simulation

    Institute of Scientific and Technical Information of China (English)

    陈溪; 刘韬; 谭光慧; 纪延超

    2006-01-01

    由Cuk DC/DC变换器的拓扑结构导出一种只具有两个开关的PWM AC/AC变换器的简单新型拓扑--Cuk AC/AC变换器.给出单相和三相Cuk AC/AC变换器的拓扑结构,分析Cuk AC/AC变换器的外特性及小信号特性.仿真结果验证了所提的Cuk AC/AC变换器的合理性和可行性.

  18. Modelling ac ripple currents in HTS coated conductors

    Science.gov (United States)

    Xu, Zhihan; Grilli, Francesco

    2015-10-01

    Dc transmission using high temperature superconducting (HTS) coated conductors (CCs) offers a promising solution to the globally growing demand for effective, reliable and economic transmission of green energy up to the gigawatt level over very long distances. The credible estimation of the losses and thereby the heat dissipation involved, where ac ripples (introduced in rectification/ac-dc conversion) are viewed as a potential source of notable contribution, is highly essential for the rational design of practical HTS dc transmission cables and corresponding cryogenic systems to fulfil this demand. Here we report a targeted modelling study into the ac losses in a HTS CC subject to dc and ac ripple currents simultaneously, by solving Maxwell’s equations using the finite element method (FEM) in the commercial software package COMSOL. It is observed that the instantaneous loss exhibits only one peak per cycle in the HTS CC subject to sinusoidal ripples, given that the amplitude of the ac ripples is smaller than approximately 20% of that of the dc current. This is a distinct contrast to the usual observation of two peaks per cycle in a HTS CC subject to ac currents only. The unique mechanism is also revealed, which is directly associated with the finding that, around any local minima of the applied ac ripples, the critical state of -J c is never reached at the edges of the HTS CC, as it should be according to the Bean model. When running further into the longer term, it is discovered that the ac ripple loss of the HTS CC in full-wave rectification decays monotonically, at a speed which is found to be insensitive to the frequency of the applied ripples within our targeted situations, to a relatively low level of approximately 1.38 × 10-4 W m-1 in around 1.7 s. Comparison between this level and other typical loss contributions in a HTS dc cable implies that ac ripple currents in HTS CCs should only be considered as a minor source of dissipation in superconducting dc

  19. Impedance, AC conductivity and dielectric behavior Adeninium Trichloromercurate (II)

    Science.gov (United States)

    Fersi, M. Amine; Chaabane, I.; Gargouri, M.

    2016-09-01

    In this work, we report the measurements impedance spectroscopy technique for the organic-inorganic hybrid compound (C5H6N5) HgCl3, 11/2H2O measured in the 209 Hz-5 MHz frequency range from 378 to 428 K. Besides, the Cole-Cole (Z″ versus Z‧) plots were well fitted to an equivalent circuit built up by a parallel combination of resistance (R), fractal capacitance (CPE) and capacitance (C). Furthermore, the AC conductivity was investigated as a function of temperature and frequency in the same range. The experiment results indicated that AC conductivity (σac) was proportional to σdc + A ωS . The obtained results are discussed in terms of the correlated barrier hopping (CBH) model. An agreement between the experimental and theoretical results suggests that the AC conductivity behavior of Adeninium Trichloromercurate (II) can be successfully explained by CBH model. The contribution of single polaron hopping to AC conductivity in a present alloy was also studied.

  20. Design and synthesis of {sup 225}Ac radioimmunopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    McDevitt, Michael R.; Ma, Dangshe; Simon, Jim; Frank, R. Keith; Scheinberg, David A. E-mail: d-scheinberg@ski.mskcc.org

    2002-12-01

    The alpha-particle-emitting radionuclides {sup 213}Bi, {sup 211}At, {sup 224}Ra are under investigation for the treatment of leukemias, gliomas, and ankylosing spondylitis, respectively. {sup 213}Bi and {sup 211}At were attached to monoclonal antibodies and used as targeted immunotherapeutic agents while unconjugated {sup 224}Ra chloride selectively seeks bone. {sup 225}Ac possesses favorable physical properties for radioimmunotherapy (10 d half-life and 4 net alpha particles), but has a history of unfavorable radiolabeling chemistry and poor metal-chelate stability. We selected functionalized derivatives of DOTA as the most promising to pursue from out of a group of potential {sup 225}Ac chelate compounds. A two-step synthetic process employing either MeO-DOTA-NCS or 2B-DOTA-NCS as the chelating moiety was developed to attach {sup 225}Ac to monoclonal antibodies. This method was tested using several different IgG systems. The chelation reaction yield in the first step was 93{+-}8% radiochemically pure (n=26). The second step yielded {sup 225}Ac-DOTA-IgG constructs that were 95{+-}5% radiochemically pure (n=27) and the mean percent immunoreactivity ranged from 25% to 81%, depending on the antibody used. This process has yielded several potential novel targeted {sup 225}Ac-labeled immunotherapeutic agents that may now be evaluated in appropriate model systems and ultimately in humans.

  1. AC propulsion system for an electric vehicle, phase 2

    Science.gov (United States)

    Slicker, J. M.

    1983-01-01

    A second-generation prototype ac propulsion system for a passenger electric vehicle was designed, fabricated, tested, installed in a modified Mercury Lynx vehicle and track tested at the Contractor's site. The system consisted of a Phase 2, 18.7 kw rated ac induction traction motor, a 192-volt, battery powered, pulse-width-modulated, transistorized inverter packaged for under rear seat installation, a 2-axis, 2-speed, automatically-shifted mechanical transaxle and a microprocessor-based powertrain/vehicle controller. A diagnostics computer to assist tuning and fault finding was fabricated. Dc-to-mechanical-system efficiency varied from 78% to 82% as axle speed/torque ranged from 159 rpm/788 nm to 65 rpm/328 nm. Track test efficiency results suggest that the ac system will be equal or superior to dc systems when driving urban cycles. Additional short-term work is being performed under a third contract phase (AC-3) to raise transaxle efficiency to predicted levels, and to improve starting and shifting characteristics. However, the long-term challenge to the system's viability remains inverter cost. A final report on the Phase 2 system, describing Phase 3 modifications, will be issued at the conclusion of AC-3.

  2. AC Zeeman potentials for atom chip-based ultracold atoms

    Science.gov (United States)

    Fancher, Charles; Pyle, Andrew; Ziltz, Austin; Aubin, Seth

    2015-05-01

    We present experimental and theoretical progress on using the AC Zeeman force produced by microwave magnetic near-fields from an atom chip to manipulate and eventually trap ultracold atoms. These AC Zeeman potentials are inherently spin-dependent and can be used to apply qualitatively different potentials to different spin states simultaneously. Furthermore, AC Zeeman traps are compatible with the large DC magnetic fields necessary for accessing Feshbach resonances. Applications include spin-dependent trapped atom interferometry and experiments in 1D many-body physics. Initial experiments and results are geared towards observing the bipolar detuning-dependent nature of the AC Zeeman force at 6.8 GHz with ultracold 87Rb atoms trapped in the vicinity of an atom chip. Experimental work is also underway towards working with potassium isotopes at frequencies of 1 GHz and below. Theoretical work is focused on atom chip designs for AC Zeeman traps produced by magnetic near-fields, while also incorporating the effect of the related electric near-fields. Electromagnetic simulations of atom chip circuits are used for mapping microwave propagation in on-chip transmission line structures, accounting for the skin effect, and guiding impedance matching.

  3. AC losses in circular arrangements of parallel superconducting tapes

    DEFF Research Database (Denmark)

    Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten; Däumling, Manfred

    1998-01-01

    The DC and AC properties of superconducting tapes connected in parellel and arranged in a single closed layer on two tubes (correspondig to power cable models with infinite pitch) with different diameters are compared. We find that the DC properties, i.e. the critical currents of the two arrangem......The DC and AC properties of superconducting tapes connected in parellel and arranged in a single closed layer on two tubes (correspondig to power cable models with infinite pitch) with different diameters are compared. We find that the DC properties, i.e. the critical currents of the two...... arrangements, scale with the number of tapes and hence appear to be independent of the diameter.However, the AC loss per tape (for a given current per tape) appears to decrease with increasing diameter of the circular arrangement. Compared to a model for the AC loss in a continuous superconducting layer...... (Monoblock model) the measured values are about half an order of magnitude higher than expected for the small diameter arrangement. When compared to the AC loss calculated for N individual superconducting tapes using a well known model ( Norris elliptical) the difference is slightly smaller....

  4. COMPARISON OF BACTERIAL ADSORPTION AND ANTIBACTERIAL PROPERTIES BETWEEN AC AND AC(Ag)%AC及AC(Ag)对细菌的吸附及灭菌功能的对比研究

    Institute of Scientific and Technical Information of China (English)

    万怡灶; 王玉林; 董向红; 周福刚; 成国祥; 温廷益; 韩森

    2000-01-01

    测定了活性碳(AC)及载银活性碳(AC(Ag))的比表面积和孔径分布曲线,对比研究了AC及AC(Ag))对大肠杆菌的吸附能力和灭菌性能.结果表明,载银后,虽然AC(Ag)的比表面积下降,但由于银的存在,使其吸附的大肠杆菌数量高于AC,而吸附速率低于AC.灭菌试验表明,AC对大肠杆菌没有杀灭能力,而AC(Ag)对大肠杆菌有较好的灭菌功能.

  5. Variable transposition of eight maize activator (ac) elements located on the short arm of chromosome 1.

    Science.gov (United States)

    Sheridan, William F

    2011-09-01

    Eight Activator (Ac) transposable elements mapped to the maize chromosome arm 1S were assessed for Ac transposition rates. For each of the Ac stocks, plants homozygous for the single Ac element and the Ds reporter r1-sc:m3 on chromosome 10 were crossed as females by a homozygous r1-sc:m3 tester color-converted W22 line. The resulting ears produced mostly coarsely spotted kernels and a low frequency of either near-colorless fine-spotted kernels or nonspotted kernels. The relative frequency of these two types of near-colorless kernels differed among the eight Ac stocks. The extent to which increased Ac dosage results in nonspotted kernels may be Ac-specific. Although all of the Ac elements are in near-isogenic inbred W22 lines, they varied to a large extent in their transposition frequency. These differences might possibly result from structural differences among the Ac elements. Because one pair of Ac elements derived from Ac33 on chromosome arm 5S differed about 13-fold in transposition frequency and a second pair of Ac elements derived from Ac12 on chromosome arm 1S differed about 3-fold in transposition frequency, this is not a likely explanation for all eight Ac elements. The data presented here support the notion that the differences in transposition frequency of the eight Ac elements may be a reflection of variability in Ac transcription or accessibility of the transposase to the Ac element, resulting from differences in the chromatin environments wherein the Ac elements are located. This is the first report of variability in transposition rates among different Ac donor lines.

  6. Superconducting shielded core reactor with reduced AC losses

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Yung S.; Hull, John R.

    2006-04-04

    A superconducting shielded core reactor (SSCR) operates as a passive device for limiting excessive AC current in a circuit operating at a high power level under a fault condition such as shorting. The SSCR includes a ferromagnetic core which may be either closed or open (with an air gap) and extends into and through a superconducting tube or superconducting rings arranged in a stacked array. First and second series connected copper coils each disposed about a portion of the iron core are connected to the circuit to be protected and are respectively wound inside and outside of the superconducting tube or rings. A large impedance is inserted into the circuit by the core when the shielding capability of the superconducting arrangement is exceeded by the applied magnetic field generated by the two coils under a fault condition to limit the AC current in the circuit. The proposed SSCR also affords reduced AC loss compared to conventional SSCRs under continuous normal operation.

  7. On the Application of TLS Techniques to AC Electrical Drives

    Directory of Open Access Journals (Sweden)

    M. Cirrincione

    2005-03-01

    Full Text Available This paper deals with the application of a new neuron, the TLS EXIN neuron, to AC induction motor drives. In particular, it addresses two important subjects of AC induction motor drives: the on-line estimation of the electrical parameters of the machine and the speed estimation in sensorless drives. On this basis, this work summarizes the parameter estimation and sensorless techniques already developed by the authors over these last few years, all based on the TLS EXIN. With regard to sensorless, two techniques are proposed: one based on the MRAS and the other based on the full-order Luenberger observer. The work show some of the most significant results obtained by the authors in these fields and stresses the important potentiality of this new neural technique in AC induction machine drives.

  8. Neural network based PWM AC chopper fed induction motor drive

    Directory of Open Access Journals (Sweden)

    Venkatesan Jamuna

    2009-01-01

    Full Text Available In this paper, a new Simulink model for a neural network controlled PWM AC chopper fed single phase induction motor is proposed. Closed loop speed control is achieved using a neural network controller. To maintain a constant fluid flow with a variation in pressure head, drives like fan and pump are operated with closed loop speed control. The need to improve the quality and reliability of the drive circuit has increased because of the growing demand for improving the performance of motor drives. With the increased availability of MOSFET's and IGBT's, PWM converters can be used efficiently in low and medium power applications. From the simulation studies, it is seen that the PWM AC chopper has a better harmonic spectrum and lesser copper loss than the Phase controlled AC chopper. It is observed that the drive system with the proposed model produces better dynamic performance, reduced overshoot and fast transient response. .

  9. Strongly nonlinear dynamics of electrolytes in large ac voltages

    DEFF Research Database (Denmark)

    Olesen, Laurits Højgaard; Bazant, Martin Z.; Bruus, Henrik

    2010-01-01

    We study the response of a model microelectrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider the simplest possible model of a symmetric binary electrolyte confined between parallel-plate blocking electrodes...... in the electrolyte near the electrodes and, at very large voltage, the breakdown of the quasiequilibrium structure of the double layers. The former leads to the prediction of “ac capacitive desalination” since there is a time-averaged transfer of salt from the bulk to the double layers, via oscillating diffusion...... nonlinear responses to large ac voltages, such as Faradaic reactions, electro-osmotic instabilities, and induced-charge electrokinetic phenomena....

  10. Structural, ac conductivity and dielectric properties of 3-formyl chromone

    Science.gov (United States)

    Ali, H. A. M.

    2017-07-01

    The structure for the powder of 3-formyl chromone was examined by X-ray diffraction technique in the 2θ° range ( 4° - 60° . The configuration of Al/3-formyl chromone/Al samples was designed. The electrical and dielectric properties were studied as a function of frequency (42- 5 × 106 Hz) and temperature (298-408K). The ac conductivity data of bulk of 3-formyl chromone varies as a power law with the frequency at different temperatures. The predominant mechanism for ac conduction was deduced. The ac conductivity shows a thermally activated process at different frequencies. The dielectric constant and dielectric loss were determined using the capacitance and dissipation factor measurements at different temperatures. The dielectric loss shows a peak of relaxation time that shifted to higher frequency with an increase in the temperature. The activation energy of the relaxation process was estimated.

  11. Reliability of emergency ac power systems at nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Battle, R E; Campbell, D J

    1983-07-01

    Reliability of emergency onsite ac power systems at nuclear power plants has been questioned within the Nuclear Regulatory Commission (NRC) because of the number of diesel generator failures reported by nuclear plant licensees and the reactor core damage that could result from diesel failure during an emergency. This report contains the results of a reliability analysis of the onsite ac power system, and it uses the results of a separate analysis of offsite power systems to calculate the expected frequency of station blackout. Included is a design and operating experience review. Eighteen plants representative of typical onsite ac power systems and ten generic designs were selected to be modeled by fault trees. Operating experience data were collected from the NRC files and from nuclear plant licensee responses to a questionnaire sent out for this project.

  12. Recurrent Security Gaps In 802.11ac Routers

    Directory of Open Access Journals (Sweden)

    Mohammed Farik

    2015-08-01

    Full Text Available Abstract In comparison to earlier IEEE 802.11 standard abgn routers todays popular 802.11ac standard routers have enhanced security. However 802.11ac router still has major security vulnerabilities. The novelty of this paper is that we not only highlight multiple security vulnerabilities in 802.11ac router technologies that still have not been secured since the earlier standards but also present some new ideas with solutions. We believe that our line of thoughts on security vulnerabilities gaps and on new solutions will provide network security researchers router manufacturers and network administrators with new disclosures to redesign even better security mechanisms in routers to counter attacks on networks via routers.

  13. Harmonic-free line-commutated ac/dc rectifiers

    Energy Technology Data Exchange (ETDEWEB)

    Villablanca, Miguel E. [Electrical Engineering Department, University of Santiago, P.O. Box 10233, Santiago (Chile)

    2009-11-15

    In this paper both a method and apparatus are applied to different configurations of line-commutated ac/dc rectifiers to reduce the distortion of currents flowing from the ac supply. The load may be either inductive or capacitive. The technology involves an accurate shaping of the dc current by using two self-commutated switches. This dc-current shaping is reflected back into the shaping of the ac input currents, which become pure sine waves. Thyristor-based rectifying operation is possible with a simple control circuit, which is able to deal with both rapid load variations and failures in the self-commutated switches. Furthermore, the overlap conduction of bridge thyristors is eliminated completely. Experimental verification is provided from a 400-V 30-kVA 50-Hz laboratory prototype. (author)

  14. Introducing high performance distributed logging service for ACS

    Science.gov (United States)

    Avarias, Jorge A.; López, Joao S.; Maureira, Cristián; Sommer, Heiko; Chiozzi, Gianluca

    2010-07-01

    The ALMA Common Software (ACS) is a software framework that provides the infrastructure for the Atacama Large Millimeter Array and other projects. ACS, based on CORBA, offers basic services and common design patterns for distributed software. Every properly built system needs to be able to log status and error information. Logging in a single computer scenario can be as easy as using fprintf statements. However, in a distributed system, it must provide a way to centralize all logging data in a single place without overloading the network nor complicating the applications. ACS provides a complete logging service infrastructure in which every log has an associated priority and timestamp, allowing filtering at different levels of the system (application, service and clients). Currently the ACS logging service uses an implementation of the CORBA Telecom Log Service in a customized way, using only a minimal subset of the features provided by the standard. The most relevant feature used by ACS is the ability to treat the logs as event data that gets distributed over the network in a publisher-subscriber paradigm. For this purpose the CORBA Notification Service, which is resource intensive, is used. On the other hand, the Data Distribution Service (DDS) provides an alternative standard for publisher-subscriber communication for real-time systems, offering better performance and featuring decentralized message processing. The current document describes how the new high performance logging service of ACS has been modeled and developed using DDS, replacing the Telecom Log Service. Benefits and drawbacks are analyzed. A benchmark is presented comparing the differences between the implementations.

  15. Modeling and Correcting the Time-Dependent ACS PSF

    Science.gov (United States)

    Rhodes, Jason; Massey, Richard; Albert, Justin; Taylor, James E.; Koekemoer, Anton M.; Leauthaud, Alexie

    2006-01-01

    The ability to accurately measure the shapes of faint objects in images taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST) depends upon detailed knowledge of the Point Spread Function (PSF). We show that thermal fluctuations cause the PSF of the ACS Wide Field Camera (WFC) to vary over time. We describe a modified version of the TinyTim PSF modeling software to create artificial grids of stars across the ACS field of view at a range of telescope focus values. These models closely resemble the stars in real ACS images. Using 10 bright stars in a real image, we have been able to measure HST s apparent focus at the time of the exposure. TinyTim can then be used to model the PSF at any position on the ACS field of view. This obviates the need for images of dense stellar fields at different focus values, or interpolation between the few observed stars. We show that residual differences between our TinyTim models and real data are likely due to the effects of Charge Transfer Efficiency (CTE) degradation. Furthermore, we discuss stochastic noise that is added to the shape of point sources when distortion is removed, and we present MultiDrizzle parameters that are optimal for weak lensing science. Specifically, we find that reducing the MultiDrizzle output pixel scale and choosing a Gaussian kernel significantly stabilizes the resulting PSF after image combination, while still eliminating cosmic rays/bad pixels, and correcting the large geometric distortion in the ACS. We discuss future plans, which include more detailed study of the effects of CTE degradation on object shapes and releasing our TinyTim models to the astronomical community.

  16. Study of AC/RF properties of SRF ingot niobium

    Energy Technology Data Exchange (ETDEWEB)

    Dhakal, Pashupati; Tsindlekht, Menachem I; Genkin, Valery M; Ciovati, Gianluigi; Myneni, Ganapati Rao

    2013-09-01

    In an attempt to correlate the performance of superconducting radiofrequency cavities made of niobium with the superconducting properties, we present the results of the magnetization and ac susceptibility of the niobium used in the superconducting radiofrequency cavity fabrication. The samples were subjected to buffer chemical polishing (BCP) surface and high temperature heat treatments, typically applied to the cavities fabrications. The analysis of the results show the different surface and bulk ac conductivity for the samples subjected to BCP and heat treatment. Furthermore, the RF surface impedance is measured on the sample using a TE011 microwave cavity for a comparison to the low frequency measurements.

  17. Power converters and AC electrical drives with linear neural networks

    CERN Document Server

    Cirrincione, Maurizio

    2012-01-01

    The first book of its kind, Power Converters and AC Electrical Drives with Linear Neural Networks systematically explores the application of neural networks in the field of power electronics, with particular emphasis on the sensorless control of AC drives. It presents the classical theory based on space-vectors in identification, discusses control of electrical drives and power converters, and examines improvements that can be attained when using linear neural networks. The book integrates power electronics and electrical drives with artificial neural networks (ANN). Organized into four parts,

  18. Development of an AC Module System: Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Suparna Kadam; Miles Russell

    2012-06-15

    The GreenRay Inc. program focused on simplifying solar electricity and making it affordable and accessible to the mainstream population. This was accomplished by integrating a solar module, micro-inverter, mounting and monitoring into a reliable, 'plug and play' AC system for residential rooftops, offering the following advantages: (1) Reduced Cost: Reduction in installation labor with fewer components, faster mounting, faster wiring. (2) Maximized Energy Production: Each AC Module operates at its maximum, reducing overall losses from shading, mismatch, or module downtime. (3) Increased Safety. Electrical and fire safety experts agree that AC Modules have significant benefits, with no energized wiring or live connections during installation, maintenance or emergency conditions. (4) Simplified PV for a Broader Group of Installers. Dramatic simplification of design and installation of a solar power system, enabling faster and more efficient delivery of the product into the market through well-established, mainstream channels. This makes solar more accessible to the public. (5) Broadened the Rooftop Market: AC Modules enable solar for many homes that have shading, split roofs, or obstructions. In addition, due to the smaller building block size of 200W vs. 1000W, homeowners with budget limitations can start small and add to their systems over time. Through this DOE program GreenRay developed the all-in-one AC Module system with an integrated PV Module and microinverter, custom residential mounting and performance monitoring. Development efforts took the product from its initial concept, through prototypes, to a commercial product sold and deployed in the residential market. This pilot deployment has demonstrated the technical effectiveness of the AC Module system in meeting the needs and solving the problems of the residential market. While more expensive than the traditional central inverter systems at the pilot scale, the economics of AC Modules become

  19. Productos «Celotex» para acondicionamientos Acústicos

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1958-02-01

    Full Text Available Not availableBajo la denominación general «Celotex», que es un nombre registrado, la Casa Americana The Celotex Corporation, cuyo domicilio social es 120 South, La Salle Street, Chicago J. lllinois, fabrica diversos materiales para fines de acondicionamiento acústico elaborados, según los tipos de que se trate, con fibra de caña de azúcar, lanas minerales, acero, amianto, etc., perforados o no y de acuerdo con el efecto estético y acústico que se desee obtener.

  20. AC and Phase Sensing of Nanowires for Biosensing.

    Science.gov (United States)

    Crescentini, Marco; Rossi, Michele; Ashburn, Peter; Lombardini, Marta; Sangiorgi, Enrico; Morgan, Hywel; Tartagni, Marco

    2016-04-19

    Silicon nanowires are label-free sensors that allow real-time measurements. They are economical and pave the road for point-of-care applications but require complex readout and skilled personnel. We propose a new model and technique for sensing nanowire sensors using alternating currents (AC) to capture both magnitude and phase information from the sensor. This approach combines the advantages of complex impedance spectroscopy with the noise reduction performances of lock-in techniques. Experimental results show how modifications of the sensors with different surface chemistries lead to the same direct-current (DC) response but can be discerned using the AC approach.

  1. Development of an AC Module System: Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Suparna Kadam; Miles Russell

    2012-06-15

    The GreenRay Inc. program focused on simplifying solar electricity and making it affordable and accessible to the mainstream population. This was accomplished by integrating a solar module, micro-inverter, mounting and monitoring into a reliable, 'plug and play' AC system for residential rooftops, offering the following advantages: (1) Reduced Cost: Reduction in installation labor with fewer components, faster mounting, faster wiring. (2) Maximized Energy Production: Each AC Module operates at its maximum, reducing overall losses from shading, mismatch, or module downtime. (3) Increased Safety. Electrical and fire safety experts agree that AC Modules have significant benefits, with no energized wiring or live connections during installation, maintenance or emergency conditions. (4) Simplified PV for a Broader Group of Installers. Dramatic simplification of design and installation of a solar power system, enabling faster and more efficient delivery of the product into the market through well-established, mainstream channels. This makes solar more accessible to the public. (5) Broadened the Rooftop Market: AC Modules enable solar for many homes that have shading, split roofs, or obstructions. In addition, due to the smaller building block size of 200W vs. 1000W, homeowners with budget limitations can start small and add to their systems over time. Through this DOE program GreenRay developed the all-in-one AC Module system with an integrated PV Module and microinverter, custom residential mounting and performance monitoring. Development efforts took the product from its initial concept, through prototypes, to a commercial product sold and deployed in the residential market. This pilot deployment has demonstrated the technical effectiveness of the AC Module system in meeting the needs and solving the problems of the residential market. While more expensive than the traditional central inverter systems at the pilot scale, the economics of AC Modules become

  2. Active Power Regulation based on Droop for AC Microgrid

    DEFF Research Database (Denmark)

    Li, Chendan; Coelho, Ernane A. A.; Firoozabadi, Mehdi Savaghebi

    2015-01-01

    In this paper, two different control strategies are proposed to address the active power regulation issue in AC microgrids. The principle of power regulation in the droop controller is firstly introduced. Frequency scheduling and droop gain scheduling on top of droop control is proposed to succes......In this paper, two different control strategies are proposed to address the active power regulation issue in AC microgrids. The principle of power regulation in the droop controller is firstly introduced. Frequency scheduling and droop gain scheduling on top of droop control is proposed...

  3. System and method for determining stator winding resistance in an AC motor using motor drives

    Science.gov (United States)

    Lu, Bin; Habetler, Thomas G; Zhang, Pinjia

    2013-02-26

    A system and method for determining the stator winding resistance of AC motors is provided. The system includes an AC motor drive having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, a pulse width modulation (PWM) converter having switches therein to control current flow and terminal voltages in the AC motor, and a control system connected to the PWM converter. The control system generates a command signal to cause the PWM converter to control an output of the AC motor drive corresponding to an input to the AC motor, selectively generates a modified command signal to cause the PWM converter to inject a DC signal into the output of the AC motor drive, and determines a stator winding resistance of the AC motor based on the DC signal of at least one of the voltage and current.

  4. 升降式交流斩波器%Buck-Boost AC/AC Direct Converter

    Institute of Scientific and Technical Information of China (English)

    孙刚; 洪峰

    2009-01-01

    介绍了一种新颖的Buck-Boost型交流斩波器.该交流斩波器将Buck-Boost型DC/DC变换器的开关管双向化,可实现单级降压或升压的AC/AC直接变换和能量双向流动.该变换器使用较少的功率器件实现了单级功率变换和能量双向流动,有利于提高变换器的功率密度和变换效率.详细研究了其工作模态和原理.分析了该变换器的两种PWM调制策略,并指出采用第2种调制策略可降低开关损耗.采用滞环电流控制的Buck/Boost型交流斩波器可对输入电压畸变进行有效抑制,保持了输出电压波形的高度正弦化.仿真和实验验证了分析的正确性.

  5. Impacts on Power Factor of AC Voltage Controllers Under Non-Sinusoidal Conditions

    Directory of Open Access Journals (Sweden)

    Mukhtiar Ahmed Mahar

    2012-04-01

    Full Text Available AC-AC conversion is obtained with the help of Cyclo-converters, DC Link converters and AC Voltage Controllers. AC voltage controllers are also referred to as voltage regulators. Main issue concerned to these converters is that they generate harmonics due to periodic variable structure system. The generated harmonics create disturbances and degrade the performance of converter. The power factor of supply side is affected due to these harmonics. This paper focuses on source side power factor of ac voltage controllers under nonsinusoidal conditions. In order to observe the power factor, measurement tool of power factor and simulation model of ac voltage controller is also developed in MATLAB software.

  6. Modulation schemes with enhanced switch thermal distribution for single-phase AC-DC-AC reduced-switch converters

    DEFF Research Database (Denmark)

    Qin, Zian; Loh, Poh Chiang; Blaabjerg, Frede

    2015-01-01

    ulation schemes can significantly change the performance of a power converter in steady state, and they have been extensively studied, but mostly directed to three-phase topologies, where triplen offsets are added. Single-phase systems, including ac-dc-ac systems, are less widely pursued, even...... among their switches, while keeping their dc-link voltages low. Single points of failure are thus minimized, allowing the converters to have longer lifetimes. Simulation and experimental results have demonstrated the intended performances and hence verifying the idea....

  7. Two very long chain fatty acid acyl-CoA synthetase genes, acs-20 and acs-22, have roles in the cuticle surface barrier in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Eriko Kage-Nakadai

    Full Text Available In multicellular organisms, the surface barrier is essential for maintaining the internal environment. In mammals, the barrier is the stratum corneum. Fatty acid transport protein 4 (FATP4 is a key factor involved in forming the stratum corneum barrier. Mice lacking Fatp4 display early neonatal lethality with features such as tight, thick, and shiny skin, and a defective skin barrier. These symptoms are strikingly similar to those of a human skin disease called restrictive dermopathy. FATP4 is a member of the FATP family that possesses acyl-CoA synthetase activity for very long chain fatty acids. How Fatp4 contributes to skin barrier function, however, remains to be elucidated. In the present study, we characterized two Caenorhabditis elegans genes, acs-20 and acs-22, that are homologous to mammalian FATPs. Animals with mutant acs-20 exhibited defects in the cuticle barrier, which normally prevents the penetration of small molecules. acs-20 mutant animals also exhibited abnormalities in the cuticle structure, but not in epidermal cell fate or cell integrity. The acs-22 mutants rarely showed a barrier defect, whereas acs-20;acs-22 double mutants had severely disrupted barrier function. Moreover, the barrier defects of acs-20 and acs-20;acs-22 mutants were rescued by acs-20, acs-22, or human Fatp4 transgenes. We further demonstrated that the incorporation of exogenous very long chain fatty acids into sphingomyelin was reduced in acs-20 and acs-22 mutants. These findings indicate that C. elegans Fatp4 homologue(s have a crucial role in the surface barrier function and this model might be useful for studying the fundamental molecular mechanisms underlying human skin barrier and relevant diseases.

  8. BOLD signal effects of transcranial alternating current stimulation (tACS) in the alpha range: A concurrent tACS-fMRI study.

    Science.gov (United States)

    Vosskuhl, Johannes; Huster, René J; Herrmann, Christoph S

    2016-10-15

    Many studies have proven transcranial alternating current stimulation (tACS) to manipulate brain activity. Until now it is not known, however, how these manipulations in brain activity are represented in brain metabolism or how spatially specific these changes are. Alpha-tACS has been shown to enhance the amplitude of the individual alpha frequency (IAF) and a negative correlation between alpha amplitude and occipital BOLD signal was reported in numerous EEG/fMRI experiments. Thus, alpha-tACS was chosen to test the effects of tACS on the BOLD signal. A reduction thereof was expected during alpha-tACS which shows the spatial extent of tACS effects beyond modeling studies. Three groups of subjects were measured in an MRI scanner, receiving tACS at either their IAF (N=11), 1Hz (control; N=12) or sham (i.e., no stimulation - a second control; N=11) while responding to a visual vigilance task. Stimulation was administered in an interleaved pattern of tACS-on runs and tACS-free baseline periods. The BOLD signal was analyzed in response to tACS-onset during resting state and in response to seldom target stimuli. Alpha-tACS at 1.0mA reduced the task-related BOLD response to visual targets in the occipital cortex as compared to tACS-free baseline periods. The deactivation was strongest in an area where the BOLD signal was shown to correlate negatively with alpha amplitude. A direct effect of tACS on resting state BOLD signal levels could not be shown. Our findings suggest that tACS-related changes in BOLD activity occur only as a modulation of an existing BOLD response.

  9. Equivalent Circuits For AC-Impedance Analysis Of Corrosion

    Science.gov (United States)

    Danford, M. D.

    1992-01-01

    Report presents investigation of equivalent circuits for ac-impedance analysis of corrosion. Impedance between specimen and electrolyte measured as function of frequency. Data used to characterize corrosion electrochemical system in terms of equivalent circuit. Eleven resistor/capacitor equivalent-circuit models were analyzed.

  10. harmonics: generation and suppression in ac system networks

    African Journals Online (AJOL)

    2012-11-03

    Nov 3, 2012 ... HARMONICS: GENERATION AND SUPPRESSION IN AC. SYSTEM NETWORKS .... If Vs = 295V; Z = (8 + j6)Ω and δ = 2π/3, the output voltage, Vo and ... tor current assume the characteristics shown in figure. 8. The output ...

  11. Current Control of Grid Converters Connected with Series AC Capacitor

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2015-01-01

    The series ac capacitor has recently been used with the transformerless grid-connected converters in the distribution power grids. The capacitive characteristic of the resulting series LC filter restricts the use of conventional synchronous integral or stationary resonant current controllers. Thus...

  12. Calculation of AC losses in large HTS stacks and coils

    DEFF Research Database (Denmark)

    Zermeno, Victor; Abrahamsen, Asger Bech; Mijatovic, Nenad;

    2012-01-01

    In this work, we present a homogenization method to model a stack of HTS tapes under AC applied transport current or magnetic field. The idea is to find an anisotropic bulk equivalent for the stack of tapes, where the internal alternating structures of insulating, metallic, superconducting and su...

  13. Novel dielectric reduces corona breakdown in ac capacitors

    Science.gov (United States)

    Loehner, J. L.

    1972-01-01

    Dielectric system was developed which consists of two layers of 25-gage paper separated by one layer of 50-gage polypropylene to reduce corona breakdown in ac capacitors. System can be used in any alternating current application where constant voltage does not exceed 400 V rms. With a little research it could probably be increased to 700 to 800 V rms.

  14. Dielectric relaxation and ac conductivity of sodium tungsten phosphate glasses

    Indian Academy of Sciences (India)

    B Singh; P S Tarsikka; L Singh

    2002-10-01

    Studies of dielectric relaxation and ac conductivity have been made on three samples of sodium tungsten phosphate glasses over a temperature range of 77–420 K. Complex relative permittivity data have been analyzed using dielectric modulus approach. Conductivity relaxation frequency increases with the increase of temperature. Activation energy for conductivity relaxation has also been evaluated. Measured ac conductivity (m()) has been found to be higher than dc at low temperatures whereas at high temperature m() becomes equal to dc at all frequencies. The ac conductivity obeys the relation ac() = A over a considerable range of low temperatures. Values of exponent are nearly equal to unity at about 78 K and the values decrease non-linearly with the increase of temperature. Values of the number density of states at Fermi level ((F)) have been evaluated at 80 K assuming values of electron wave function decay constant to be 0.5 (Å)-1. Values of (F) have the order 1020 which are well within the range suggested for localized states. Present values of (F) are smaller than those for tungsten phosphate glasses.

  15. Heat Transfer Analysis for Industrial AC Electric Arc Furnace

    Institute of Scientific and Technical Information of China (English)

    (U)nal (C)amdali; Murat Tun(c)

    2005-01-01

    The heat transfer analysis was performed for an AC electric arc furnace (EAF). Heat losses by conduction, convection and radiation from outer surface, roof, bottom and electrodes of EAF were determined in detail. Some suggestions about decreasing heat losses were presented.

  16. 7 CFR 1737.31 - Area Coverage Survey (ACS).

    Science.gov (United States)

    2010-01-01

    ... Design. (Approved by the Office of Management and Budget under control number 0572-0079) ... Survey (ACS) is a market forecast of service requirements of subscribers in a proposed service area. (b... identification of future establishments are also recorded on the maps. (2) A forecast of the number of...

  17. Introducing AC Inductive Reactance with a Power Tool

    Science.gov (United States)

    Bryant, Wesley; Baker, Blane

    2016-01-01

    The concept of reactance in AC electrical circuits is often non-intuitive and difficult for students to grasp. In order to address this lack of conceptual understanding, classroom exercises compare the predicted resistance of a power tool, based on electrical specifications, to measured resistance. Once students discover that measured resistance…

  18. A simple technique for a.c. conductivity measurements

    Indian Academy of Sciences (India)

    R Padma Suvarna; K Raghavendra Rao; K Subbarangaiah

    2002-12-01

    An inexpensive, indigenous and a simple electronic instrument based on voltage follower, current–to–voltage converter, zero crossing detector and a phase detector has been developed for measurement of a.c. conductivity. Real and imaginary parts of complex impedance are determined for a given sample as a function of frequency and the given sample is represented by a pure electronic model.

  19. Rethinking Rectification: AC-DC Power Supply in Package

    DEFF Research Database (Denmark)

    Pejtersen, Jens; Knott, Arnold; Jørgensen, Ivan Harald Holger

    Rectification of AC mains voltage is almost exclusively implemented with passive diode bridge rectifiers for power applications below 100 W. The diode bridge rectifier is reliable, cost effective and easy to use. But it is also lossy, nonlinear and passive. Thus reducing the power conversion...

  20. 78 FR 42567 - ACS Wireless, Inc.; Notice of Application

    Science.gov (United States)

    2013-07-16

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION ACS Wireless, Inc.; Notice of Application June 25, 2013. Correction In notice document 2013-15658 beginning on page 39345 in the issue of Monday, July 1, 2013, make the following correction: On page...

  1. Soliton ratchetlike dynamics by ac forces with harmonic mixing

    DEFF Research Database (Denmark)

    Salerno, Mario; Zolotaryuk, Yaroslav

    2002-01-01

    The possibility of unidirectional motion of a kink (topological soliton) of a dissipative sine-Gordon equation in the presence of ac forces with harmonic mixing (at least biharmonic) and of zero mean, is presented. The dependence of the kink mean velocity on system parameters is investigated...

  2. Stretched exponential relaxation and ac universality in disordered dielectrics

    DEFF Research Database (Denmark)

    Milovanov, Alexander V.; Rypdal, Kristoffer; Juul Rasmussen, Jens

    2007-01-01

    This paper is concerned with the connection between the properties of dielectric relaxation and alternating-current (ac) conduction in disordered dielectrics. The discussion is divided between the classical linear-response theory and a self-consistent dynamical modeling. The key issues are stretc......This paper is concerned with the connection between the properties of dielectric relaxation and alternating-current (ac) conduction in disordered dielectrics. The discussion is divided between the classical linear-response theory and a self-consistent dynamical modeling. The key issues...... are stretched exponential character of dielectric relaxation, power-law power spectral density, and anomalous dependence of ac conduction coefficient on frequency. We propose a self-consistent model of dielectric relaxation in which the relaxations are described by a stretched exponential decay function....... Mathematically, our study refers to the expanding area of fractional calculus and we propose a systematic derivation of the fractional relaxation and fractional diffusion equations from the property of ac universality....

  3. Study of ac electrical properties of aluminium-epoxy composites

    Energy Technology Data Exchange (ETDEWEB)

    Elimat, Z M [Applied Science Department, Ajloun University College, Al-Balqa Applied University, Amman (Jordan); Zihlif, A M [Physics Department, University of Jordan, Amman (Jordan); Ragosta, G [Institute of Chemistry and Polymer Technology (ICTP), CNR-Possouli, Napoli (Italy)], E-mail: adzh@ju.edu.jo

    2008-08-21

    Ac electrical properties of aluminium flakes-epoxy composites were studied as a function of the composition, frequency and temperature. The dielectric constant increased smoothly with an increase in the concentration of aluminium. An increase in the dielectric constant was observed with the temperature as well as with a decrease in the frequency. The observed increase in the values of the dielectric constant with the aluminium concentration was attributed to interfacial polarization. It was found that ac electrical conductivity increases with increasing content of aluminium, temperature and frequency. The observed enhancement in ac conductivity is attributed to the increase in the number of conduction paths created by the aluminium flake contacts in the composite to give a higher electrical conductivity. Also, the activation energy of aluminium flakes-epoxy composites was determined, as well as the values of the dielectric constant. Compared with various theoretical models, Bruggman's formula gives a better fit. The universal power-law model of ac conductivity is observed in epoxy-aluminium composites. The calculated power exponent (about unity) is physically acceptable within this applied model.

  4. Recommended ACS Syllabus for Introductory Courses in Polymer Chemistry.

    Science.gov (United States)

    Seymour, Raymond B.

    1982-01-01

    Provides syllabus for courses in introductory polymer chemistry (including major topics and recommended time allotments) and currently available textbooks and audio courses which may be used with the syllabus. Syllabus topics are congruent with those used in American Chemical Society (ACS) standardized examination in polymer chemistry. (Author/JN)

  5. Calculated characteristics of an ac plasma display panel cell

    Energy Technology Data Exchange (ETDEWEB)

    Boeuf, J.P.; Pitchford, L.C. [Universite Paul Sabatier, Toulouse (France)

    1996-02-01

    Equipotential contours and contours of constant power deposition into excitation of xenon, calculated from a two-dimensional (2-D) fluid model, are presented at times during the evolution of a single discharge event in an ac plasma display panel cell with a dielectric barrier rib geometry.

  6. An overview of the ALMA Common Software (ACS) .

    Science.gov (United States)

    Di Marcantonio, P.; Cirami, R.; Caproni, A.; Chiozzi, G.; Jeram, B.; Sommer, H.; Harrington, S.; Zagar, K.; Plesko, M.; Sekoranja, M.

    The ALMA Common Software (ACS) is an application framework designed to provide a common and homogeneous software architecture and infrastructure, spanning the end to end needs of an Astronomical observatory, from the Telescope Control system to high-level data flow management. ACS offers, at the lower level, several basic services needed for object-oriented distributed computing like transparent remote object invocation, object deployment and location, distributed error, alarm handling, logging and events. On top of this it provides an application architecture based on the Component/Container paradigm that fosters sharing and reusing of software components. Although developed for the ALMA project, ACS is now used by several other projects worldwide, among which the Italian Sardinia Radio Telescope (SRT). Besides, there is an active community that shares ideas, concepts and actual software components. Major drivers for this diffusion were the choice of adopting the LGPL public license and the adoption of CORBA, a free but reliable and widely used middleware software. In this paper we present an overview of the main features of ACS, emphasizing in particular the role of INAF-OAT in this project.

  7. Container-component model and XML in ALMA ACS

    Science.gov (United States)

    Sommer, Heiko; Chiozzi, Gianluca; Zagar, Klemen; Voelter, Markus

    2004-09-01

    ALMA software, from high-level data flow applications down to instrument control, is built using the ACS framework. To meet the challenges of developing distributed software in distributed teams, ACS offers a container/component model that integrates the use of XML transfer objects. ACS containers are built on top of CORBA and are available for C++, Java, and Python, so that ALMA software can be written as components in any of these languages. The containers perform technical aspects of the software system, while components can focus on the implementation of functional requirements. Like Web services, components can use XML to exchange structured data by value. For Java components, the container seamlessly integrates the use of XML binding classes, which are Java classes that encapsulate access to XML data through type-safe methods. Binding classes are generated from XML schemas, allowing the Java compiler to enforce compliance of application code with the XML schemas. This presentation will explain the capabilities of the ACS container/component model, and how it relates to other middleware technologies that are popular in industry.

  8. Phase controlled dc-ac converter with high frequency switching

    Science.gov (United States)

    Harada, Koosuke; Sakamoto, Hiroshi; Shoyama, Masahito

    A sinusoidal dc-ac converter is presented in which a pair of switches is placed on each side of the primary and secondary of the isolation transformer. This converter is controlled by the phase difference between the two pairs of switches. The transformer is miniaturized by making the switching frequency high. This converter is especially suitable for small uninterruptible power supply systems.

  9. Acústica, fluidos y termodinámica

    OpenAIRE

    Beléndez Vázquez, Augusto

    1992-01-01

    Acústica. Estática de fluidos. Dinámica de fluidos y fluidos reales. Temperatura y propagación del calor. Primer principio de la Termodinámica. Gases ideales. Segundo principio de la Termodinámica.

  10. Conductivity measurements with trapezoidal a.c. magnetic fields

    NARCIS (Netherlands)

    Gijsbertse, E.A.; Klundert, van de L.J.M.

    1981-01-01

    The inductive response of normal metals to trapezoidal a.c. fields is studied theoretically as well as experimentally. A method is presented to determine the conductivity and its magnetic induction dependence from the decay of the induced voltage during periods of constant field. The correctness of

  11. Biocontrol activity of Paenibacillus polymyxa AC-1 against Pseudomonas syringae and its interaction with Arabidopsis thaliana.

    Science.gov (United States)

    Hong, Chi Eun; Kwon, Suk Yoon; Park, Jeong Mee

    2016-04-01

    Paenibacillus polymyxa AC-1 (AC-1) is a plant growth-promoting rhizobacterium (PGPR) that has been used as a soil inoculant for biocontrol of plant pathogenic fungi and to promote plant growth. In this study, we examine the effects of AC-1 on the bacterial phytopathogen Pseudomonas syringae and internal colonization of AC-1 by counting bacterial populations that colonize plants. AC-1 inhibited the growth of both P. syringae pv. tomato DC3000 (Pst) and P. syringae pv. tabaci (Pta) in a concentration-dependent manner in in vitro assays. Upon treatment of AC-1 dropping at root tip of axenically grown Arabidopsis, we found that most of the AC-1 was detected in interior of leaves of Arabidiopsis plants rather than roots after 5 days post infection, indicating systemic spreading of AC-1 occur. We examined further AC-1 colonization patterns in Arabidopsis mutants deficient in phytohormone signaling pathways. These results indicated that abscisic acid (ABA) and jasmonic acid (JA) signaling pathways positively and negatively contributed, respectively, to AC-1 colonization of leaves, whereas epiphytic accumulation of AC-1 around root tissues was not affected. This study shows that AC-1 is an effective biocontrol agent to suppress P. syringae growth, possibly owing to its colonization patterns as a leaf-inhabiting endophyte. The results showed in this work will help to expand our understanding of the mode of action of AC-1 as a biological control agent and consequently, its application in agriculture.

  12. Aragonite coating solutions (ACS) based on artificial seawater

    Energy Technology Data Exchange (ETDEWEB)

    Tas, A. Cuneyt, E-mail: c_tas@hotmail.com

    2015-03-01

    Graphical abstract: - Highlights: • Developed completely inorganic solutions for the deposition of monolayers of aragonite spherules (or ooids). • Solutions mimicked the artificial seawater. • Biomimetic crystallization was performed at the tropical sea surface temperature of 30 °C. - Abstract: Aragonite (CaCO{sub 3}, calcium carbonate) is an abundant biomaterial of marine life. It is the dominant inorganic phase of coral reefs, mollusc bivalve shells and the stalactites or stalagmites of geological sediments. Inorganic and initially precipitate-free aragonite coating solutions (ACS) of pH 7.4 were developed in this study to deposit monolayers of aragonite spherules or ooids on biomaterial (e.g., UHMWPE, ultrahigh molecular weight polyethylene) surfaces soaked in ACS at 30 °C. The ACS solutions of this study have been developed for the surface engineering of synthetic biomaterials. The abiotic ACS solutions, enriched with calcium and bicarbonate ions at different concentrations, essentially mimicked the artificial seawater composition and started to deposit aragonite after a long (4 h) incubation period at the tropical sea surface temperature of 30 °C. While numerous techniques for the solution deposition of calcium hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}), of low thermodynamic solubility, on synthetic biomaterials have been demonstrated, procedures related to the solution-based surface deposition of high solubility aragonite remained uncommon. Monolayers of aragonite ooids deposited at 30 °C on UHMWPE substrates soaked in organic-free ACS solutions were found to possess nano-structures similar to the mortar-and-brick-type botryoids observed in biogenic marine shells. Samples were characterized using SEM, XRD, FTIR, ICP-AES and contact angle goniometry.

  13. Flame spread over inclined electrical wires with AC electric fields

    KAUST Repository

    Lim, Seung J.

    2017-07-21

    Flame spread over polyethylene-insulated electrical wires was studied experimentally with applied alternating current (AC) by varying the inclination angle (θ), applied voltage (VAC), and frequency (fAC). For the baseline case with no electric field applied, the flame spread rate and the flame width of downwardly spreading flames (DSFs) decreased from the horizontal case for −20° ≤ θ < 0° and maintained near constant values for −90° ≤ θ < −20°, while the flame spread rate increased appreciably as the inclination angle of upwardly spreading flames (USFs) increased. When an AC electric field was applied, the behavior of flame spread rate in DSFs (USFs) could be classified into two (three) sub-regimes characterized by various functional dependences on VAC, fAC, and θ. In nearly all cases of DSFs, a globular molten polyethylene formed ahead of the spreading flame edge, occasionally dripping onto the ground. In these cases, an effective flame spread rate was defined to represent the burning rate by measuring the mass loss due to dripping. This effective spread rate was independent of AC frequency, while it decreased linearly with voltage and was independent of the inclination angle. In DSFs, when excessively high voltage and frequency were applied, the dripping led to flame extinction during propagation and the extinction frequency correlated well with applied voltage. In USFs, when high voltage and frequency were applied, multiple globular molten PEs formed at several locations, leading to ejections of multiple small flame segments from the main flame, thereby reducing the flame spread rate, which could be attributed to the electrospray phenomenon.

  14. 多元组合ACS-TSP系统%A Multi-Metaheuristic Combined ACS-TSP System

    Institute of Scientific and Technical Information of China (English)

    陈芳

    2015-01-01

    文章提出了用多算法结合蚁族系统(ACS)求解旅行商问题(TSP)的方法,介绍了在ACS-TSP问题上的遗传算法,目的是为了寻找处理旅行商早期停滞现象的解空间.此外,还提出了一种新的最小生成树(MST)算法,结合最近邻(NN)来创建一个初始架构,以便又快又好地解决旅行商问题.%This paper presents a Multi-Metaheuristic combined Ant Colony System (ACS)-Travelling Salesman Problem (TSP) al-gorithm for solving the TSP. We introduce genetic algorithm in ACS-TSP to search solutions space for dealing with the early stagnation problem of the traveling salesman problem. Moreover, we present a new strategy of Minimum Spanning Tree(MST) coupled with Nearest Neighbor(NN) to construct a initial tour for improving TSP thus obtaining good solutions quickly. According to our simulation results, the new algorithm can provide a significant improvement for obtaining a global optimum solution or a near global optimum solution in large TSPs.

  15. A Study on Power Quality Improvement in PWM Controlled AC Voltage Controller

    Directory of Open Access Journals (Sweden)

    Ahmet ALTINTAŞ

    2009-04-01

    Full Text Available A lot of topologies of pulse-width modulated (PWM-AC controllers for single-phase and three-phase systems are proposed up to date. PWM-AC controllers have important advantages compared with the phase-controlled AC controllers using thyristors and triacs. The PWM-AC controller has sinusoidal current waveforms, smaller THD values, better power factor, faster dynamics, and smaller input/output filter. This article presents a novel control technique for application to PWM-AC controllers with ability of generating fewer harmonics. In the proposed control method, both the traditional AC voltage controllers and the PWM-AC controllers are combined; and smaller THD values are obtained. Thus, the harmonic pollution in the power system will be reduced; and consequently, the power quality will be increased. For this purpose, computer simulations are performed in order to investigate the proposed controller performance. The obtained results are compared with the conventional PWM-AC controller.

  16. Recent applications of AC electrokinetics in biomolecular analysis on microfluidic devices.

    Science.gov (United States)

    Sasaki, Naoki

    2012-01-01

    AC electrokinetics is a generic term that refers to an induced motion of particles and fluids under nonuniform AC electric fields. The AC electric fields are formed by application of AC voltages to microelectrodes, which can be easily integrated into microfluidic devices by standard microfabrication techniques. Moreover, the magnitude of the motion is large enough to control the mass transfer on the devices. These advantages are attractive for biomolecular analysis on the microfluidic devices, in which the characteristics of small space and microfluidics have been mainly employed. In this review, I describe recent applications of AC electrokinetics in biomolecular analysis on microfluidic devices. The applications include fluid pumping and mixing by AC electrokinetic flow, and manipulation of biomolecules such as DNA and proteins by various AC electrokinetic techniques. Future prospects for highly functional biomolecular analysis on microfluidic devices with the aid of AC electrokinetics are also discussed.

  17. Software Development for ALMA in Chile: The ACS-UTFSM Group.

    Science.gov (United States)

    von Brand, H. H.

    ALMA Common Software (ACS) provides a common software framework for ALMA, the Atacama Large Millimeter Array in Chile. ACS is a collection of well-documented patterns for controlling systems and a set of components written to those patterns. In its core, ACS is a distributed, object-oriented system, written on top of CORBA. The ACS-UTFSM Group started as some students of informatics did summer jobs at the La Silla Observatory of ESO, where they became acquainted with ACS. Their interest led them to continue working on ACS on their own, and they eventually became official developers of the package. Now the group is being funded by project ALMA-CONICYT 31060008 ``Software Development for ALMA: Building Up Expertise to Meet ALMA Software Requirements within a Chilean University''. Several members of the original group are now working for ALMA, which fullfills one of the goals of the project. Some parts of ACS developed by the ACS-UTFSM Group include H3E (Hardware End-to-End Example), a Lego model of a telescope and its controlling software for training and demonstration purposes; and CDBChecker, a tool to verify the consistency of the configuration database for a ACS deployment. Currently we are working towards a general framework for telescope control using ACS, in order to simplify the deployment of new instruments; and repackaging ACS so it is easier to install and use. A master's thesis is exploring the real-time requirements of ACS.

  18. File list: His.PSC.50.H3ac.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.PSC.50.H3ac.AllCell mm9 Histone H3ac Pluripotent stem cell SRX882861,SRX882864,...SRX882865,SRX882862,SRX882860,SRX882863 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.PSC.50.H3ac.AllCell.bed ...

  19. Scaling of ac susceptibility and the nonlinear response function of high-temperature superconductors

    Institute of Scientific and Technical Information of China (English)

    CHEN; Kaixuan; NING; Zhenhua; XU; Hengyi; QI; Zhi; LU; Guo

    2005-01-01

    The amplitude-dependent ac susceptibility of high-temperature superconductors is shown to obey some empirical scaling relations. We try to analyze this behavior by extending a dc nonlinear response function of mixed state to the ac cases. The derived equations for critical current and ac susceptibility x(T) agree with the scaling relations of experimental data.

  20. Investigation and comparison of AC losses on stabilizer-free and copper stabilizer HTS tapes

    Science.gov (United States)

    Shen, Boyang; Li, Jing; Geng, Jianzhao; Fu, Lin; Zhang, Xiuchang; Li, Chao; Zhang, Heng; Dong, Qihuan; Ma, Jun; Coombs, T. A.

    2017-10-01

    This paper presents the measurement and simulation of Alternating Current (AC) losses on the Stabilizer-free and Copper Stabilizer High Temperature Superconducting (HTS) Tapes: SuperPower SF12100 and SCS12050. The AC loss measurement utilised electrical method to obtain overall losses with AC transport currents. The 2D H-formulation by COMSOL Multiphysics has been used to simulate the real geometry and multi-layer HTS tapes. Ferromagnetic AC losses of substrate have been assumed to be ignored as the substrates of SF12100 and SCS12050 are non-magnetic. Hysteresis AC losses in the superconducting layer, and eddy-current AC losses in copper stabilizer, silver overlayer and substrate were concerned in this investigation. The measured AC losses were compared to the AC losses from simulation, with 3 cases of different AC frequency 10, 100, and 1000 Hz. The eddy-current AC losses of copper stabilizer at frequency 1000 Hz were determined from both experiment and simulation. The estimation of AC losses with frequency at 10,000 Hz was also carried out using simulation method. Finally, the frequency dependence of AC losses from Stabilizer-free Tape and Copper Stabilizer Tape were compared and analysed.

  1. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered adjustable hospital bed. 880.5100... (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered...

  2. A Dual-Buck–Boost AC/DC Converter for DC Nanogrid With Three Terminal Outputs

    DEFF Research Database (Denmark)

    Wu, Weimin; Wang, Houqing; Liu, Yuan

    2017-01-01

    such as the low-voltage ac power system. There are three typical grounding configurations for a dc nanogrid: the united grounding, the unidirectional grounding, and the virtual isolated grounding. Each grounding configuration has its own specifications to ac/dc converters. In this paper, a dual-buck-boost ac...

  3. Examining the Effects of Introducing Online Access to ACS Journals at Primarily Undergraduate Institutions

    Science.gov (United States)

    Landolt, R. G.

    2007-01-01

    In collaboration with the Publications Division of the American Chemical Society (ACS), students and faculty at 24 primarily undergraduate institutions were provided online access to ACS primary research journals for a period of 18 months, and a group of eight schools were granted access to use the archives of ACS journals for a year. Resources…

  4. AC-13混合料矿料级配及特性试验研究%Research on AC-13 mixture mineral materials gradation and feature experiments

    Institute of Scientific and Technical Information of China (English)

    何亦伟

    2016-01-01

    The paper adopts the Marshall method and Superpave method,undertakes the mixture design for AC-13Ⅰand AC-13,compares and analyzes the optimal asphalt volume and compaction features of the two,and points out the designed asphalt volumes has the same optimal asphalt and aggregate ratio,and the latter is superior to the former one in the aspect of compaction.%应用马歇尔法和Superpave法对AC-13Ⅰ和AC-13进行了混合料设计,对比分析了两者的最佳沥青用量及压实特性,指出两者的设计沥青用量在最佳油石比时基本相同,AC-13的压实特性优于AC-13Ⅰ.

  5. Antimicrobial activity analysis of conotoxin-like peptide from AcMNPV%AcMNPV类芋螺毒素多肽的抗菌活性分析

    Institute of Scientific and Technical Information of China (English)

    曹青; 吴岩; 刘永; 吴俣; 王文兵; 朱姗颖

    2012-01-01

    类芋螺毒素(CTX)基因存在于多种杆状病毒,编码富含半胱氨酸的多肽.从AcMNPV中克隆了ctx基因,利用AcMNPV杆粒操作系统构建了重组病毒Ac-pFastBac1-Pie1-ctx-eGFP和Ac-pFastBacl-Pie1-ctx.绿色荧光蛋白介导的亚细胞定位显示AcMNPV CTX定位于Tn细胞的细胞膜;抑菌实验表明,重组病毒Ac-pFastBacl-Piel-ctx感染的胞外产物对金黄色葡萄球菌、微球菌、短小芽孢杆菌等临床致病菌具有显著的抗菌活性,但其作用机制尚需进一步阐明.%Conotoxin-like (CTX) gene encodes a small cysteine-rich peptide in various baculoviruses. In this study, the ctx gene was cloned from AcMNPV, and the recombinant AcMNPVs (Ac-pFastBac1-Pie1-ctx-eGFP and Ac-pFastBac1-Pie1-ctx) was generated using AcMNPV bacmid system. Green fluorescence in CTX-eGFP-positive Tn cells was mainly observed on the cell membrane. The results also indicated that extracullular products of Tn cells infected by Ac-pFastBac1-Pie1-ctx had antimicrobial activity to some clinical pathogenic bactera (Staphylococcus aureus, Micrococcus and Bacillus pumilus).

  6. Characterization of an Ac transposon system based on apt1-m1 (Ac) on the long arm of maize chromosome 9.

    Science.gov (United States)

    Wang, Fei; Li, Pengfei; Tang, Yuanping; Fan, Jun; Xu, Dabin; Guo, Shengming; Xu, Zhengkai; Song, Rentao

    2012-09-01

    Activator/Dissociation (Ac/Ds) transposable elements have been used in maize insertional mutagenesis as a complement to Mutator (Mu). In this study, to further improve the efficiency of the Ac/Ds mutagenesis system, we adopted apt1-m1 (Ac) on the long arm of chromosome 9 (9L) as a donor Ac to create an Ac insertion library. This system is based on the negative selection pressure against the donor Ac, and it was highly efficient for isolating new transposition events. We obtained 9,625 transposition events from 1083 F1 ears with an average transposition rate of 8.66 % (rates ranged from 1.11 to 29.73 %). We also adopted a modified PCR-based genome walking strategy to improve the efficiency of the new method for isolating transposon-flanking sequences. This method is more efficient than the Southern-based method that was used in previous studies. A validation step was developed to distinguish transposon tags derived from newly transposed Ac or Ds elements. Using this PCR-based method, we isolated 67 inheritable flanking sequences from the apt1-m1 (Ac) transposition library; of these, 51 were confirmed as tr-Ac-flanking sequences and 11 were tr-Ds-flanking sequences. Similar to other Ac donors from different loci, the apt1-m1 (Ac) system also exhibited a preference for short distance transposition. In this study, we have further improved the Ac mutagenesis system in maize for gene isolation and functional genomics studies.

  7. RNA interference suppression of mucin 5AC (MUC5AC) reduces the adhesive and invasive capacity of human pancreatic cancer cells.

    Science.gov (United States)

    Yamazoe, Sadaaki; Tanaka, Hiroaki; Sawada, Tetsuji; Amano, Ryosuke; Yamada, Nobuya; Ohira, Masaichi; Hirakawa, Kosei

    2010-05-23

    MUC5AC is a secretory mucin normally expressed in the surface muconous cells of stomach and bronchial tract. It has been known that MUC5AC de novo expression occurred in the invasive ductal carcinoma and pancreatic intraepithelial neoplasm with no detectable expression in normal pancreas, however, its function remains uncertain. Here, we report the impact of MUC5AC on the adhesive and invasive ability of pancreatic cancer cells. We used two MUC5AC expressing cell lines derived from human pancreatic cancer, SW1990 and BxPC3. Small-interfering (si) RNA directed against MUC5AC were used to assess the effects of MUC5AC on invasion and adhesion of pancreas cancer cells in vitro and in vivo. We compared parental cells (SW1990 and BxPC3) with MUC5AC suppressed cells by si RNA (si-SW1990 and si-BxPC3). MUC5AC was found to express in more than 80% of pancreatic ductal carcinoma specimens. Next we observed that both of si-SW1990 and si-BxPC3 showed significantly lower adhesion and invasion to extracellular matrix components compared with parental cell lines. Expression of genes associated with adhesion and invasion including several integerins, matrix metalloproteinase (MMP) -3 and vascular endothelial growth factor (VEGF) were down-regulated in both MUC5AC suppressed cells. Furthermore, production of VEGF and phosphorylation of VEGFR-1 were significantly reduced by MUC5AC down regulation. Both of si-SW1990 and si-BxPC3 attenuated activation of Erk1/2. In vivo, si-SW1990 did not establish subcutaneous tumor in nude mice. Knockdown of MUC5AC reduced the ability of pancreatic cancer cells to adhesion and invasion, suggesting that MUC5AC might contribute to the invasive motility of pancreatic cancer cells by enhancing the expression of integrins, MMP-3, VEGF and activating Erk pathway.

  8. Sensorless operation of surface mount permanent magnet AC (PMAC) motors

    Energy Technology Data Exchange (ETDEWEB)

    Toliyat, H.A.; Rahman, K.M.; Shet, D.S.

    1999-12-01

    A sensorless field oriented control scheme for surface mount permanent magnet ac (PMAC) motor with split phase stator windings is presented. This motor is obtained by splitting the phase windings of a conventional three phase motor. The six-phase motor, however is run as a three-phase motor by connecting the split phase stator windings in series, while the taps are made available for voltage measurements. By measuring the terminal voltages and the line currents, absolute position of the permanent magnet ac motor driven by a current regulated PWM inverter with a hysteresis controller is estimated. The estimated position information is independent of the stator resistance, thus this scheme is even applicable at low speeds. Results are presented to show the effectiveness of the new controller, and it is also shown that the position error is negligible.

  9. Droop-free Distributed Control for AC Microgrids

    DEFF Research Database (Denmark)

    Nasirian, Vahidreza; Shafiee, Qobad; Guerrero, Josep M.

    2016-01-01

    guidelines are provided. Steady-state performance analysis shows that the proposed controller can accurately handle the global voltage regulation and proportional load sharing. An AC microgrid prototype is set up, where the controller performance, plug-and-play capability, and resiliency to the failure...... active power of each inverter with its neighbors’ and uses the difference to update the frequency and, accordingly, the phase angle of that inverter. The global dynamic model of the microgrid, including distribution grid, regulator modules, and the communication network, is derived, and controller design......A cooperative distributed secondary/primary control paradigm for AC microgrids is proposed. This solution replaces the centralized secondary control and the primary-level droop mechanism of each inverter with three separate regulators: voltage, reactive power, and active power regulators. A sparse...

  10. The minimization of ac phase noise in interferometric systems

    DEFF Research Database (Denmark)

    Filinski, Ignacy; Gordon, R A

    1994-01-01

    A simple step-by-step procedure, including several novel techniques discussed in the Appendices, is given for minimizing ac phase noise in typical interferometric systems such as two-beam interferometers, holographic setups, four-wave mixers, etc. Special attention is given to index of refraction...... fluctuations, direct mechanical coupling, and acoustic coupling, whose importance in determining ac phase noise in interferometric systems has not been adequately treated. The minimization procedure must be carried out while continuously monitoring the phase noise which can be done very simply by using...... with the optical table will also have to be carefully carried out regardless of the type of interferometric system employed.It is recommended that this be followed by a simple, inexpensive change to a novel type of interferometer discussed in Appendix A which is inherently less sensitive to mechanical vibration...

  11. Towards an AC-MOT of CaF

    Science.gov (United States)

    Anderegg, Loic; Chae, Eunmi; Ravi, Aakash; Augenbraun, Benjamin; Hemmerling, Boerge; Drayna, Garrett; Hutzler, Nicholas; Collopy, Alejandra; Wu, Yewei; Ding, Shiqian; Ye, Jun; Ketterle, Wolfgang; Doyle, John

    2016-05-01

    Ultra-cold diatomic molecules have rich prospects as candidates to study controlled ultra-cold chemistry, strongly correlated systems and precision measurements. They are also considered as possible qubits in quantum computing and simulation schemes. We report on progress towards loading CaF into a molecular magneto-optical trap (MOT). An AC-MOT will be used to actively remix magnetic dark states via both polarization and magnetic field switching. In order to load a molecular MOT, we have successfully laser slowed a CaF beam to near the expected capture velocity. We describe our AC-MOT apparatus, which is designed to co-trap CaF and Li. We outline our planned study of CaF-Li collisions to explore the feasibility of sympathetically cooling molecules to ultra-cold temperatures.

  12. Ac magnetic susceptibility study of in vivo nanoparticle biodistribution

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, L; Veintemillas-Verdaguer, S; Serna, C J; Morales, M P [Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC, Sor Juana Ines de la Cruz 3, Cantoblanco 28049, Madrid (Spain); MejIas, R; Barber, D F [Centro Nacional de BiotecnologIa, CNB-CSIC, Darwin 3, Cantoblanco 28049, Madrid (Spain); Lazaro, F J, E-mail: lucia@icmm.csic.es [Departamento de Ciencia y Tecnologia de Materiales y Fluidos, Universidad de Zaragoza, Maria de Luna 3, 50018, Zaragoza (Spain)

    2011-06-29

    We analysed magnetic nanoparticle biodistribution, before and after cytokine conjugation, in a mouse model by ac susceptibility measurements of the corresponding resected tissues. Mice received repeated intravenous injections of nanoparticle suspension for two weeks and they were euthanized 1 h after the last injection. In general, only 10% of the total injected nanoparticles after multiple exposures were found in tissues. The rest of the particles may probably be metabolized or excreted by the organism. Our findings indicate that the adsorption of interferon to DMSA-coated magnetic nanoparticles changes their biodistribution, reducing the presence of nanoparticles in lungs and therefore their possible toxicity. The specific targeting of the particles to tumour tissues by the use of an external magnetic field has also been studied. Magnetic nanoparticles were observed by transmission electron microscopy in the targeted tissue and quantified by ac magnetic susceptibility.

  13. Transport signatures in topological systems coupled to ac fields

    Science.gov (United States)

    Ruocco, Leonard; Gómez-León, Álvaro

    2017-02-01

    We study the transport properties of a topological system coupled to an ac electric field by means of Floquet-Keldysh formalism. We consider a semi-infinite chain of dimers coupled to a semi-infinite metallic lead and obtain the density of states and current when the system is out of equilibrium. Our formalism is nonperturbative and allows us to explore, in the thermodynamic limit, a wide range of regimes for the ac field, arbitrary values of the coupling strength to the metallic contact and corrections to the wide-band limit (WBL). We find that hybridization with the contact can change the dimerization phase, and that the current dependence on the field amplitude can be used to discriminate between them. We also show the appearance of side bands and nonequilibrium zero-energy modes, characteristic of the Floquet systems. Our results directly apply to the stability of nonequilibrium topological phases, when transport measurements are used for their detection.

  14. 单相AC/AC Buck变换器中双向开关四步换流策略的研究%Four-step switching strategy of the bidirectional switches in single-phase AC/AC Buck converter

    Institute of Scientific and Technical Information of China (English)

    曾松; 张波; 丘东元; 马化盛

    2007-01-01

    为解决双向开关在电力电子器件中的换流问题,可采用"四象限换流"的换流策略,即"四步换流".该方法根据电压的相对大小或电流的方向将两个双向开关之间的换流过程分为四步进行,有效地避免了换流过程中的故障,实现了真正意义上的安全换流.本文以单相AC/AC Buck变换器为例,研究其中双向开关的四步换流控制策略,设计出具体的实现电路,并用实验加以验证.

  15. Improvement program for polycarbonate capacitors. [hermetically sealed, and ac wound

    Science.gov (United States)

    Bailey, R. R.; Waterman, K. D.

    1973-01-01

    Hermetically sealed, wound, AC, polycarbonate capacitors incorporating design improvements recommended in a previous study were designed and built. A 5000 hour, 400 Hz ac life test was conducted using 384 of these capacitors to verify the adequacy of the design improvements. The improvements incorporated in the capacitors designed for this program eliminated the major cause of failure found in the preceding work, termination failure. A failure cause not present in the previous test became significant in this test with capacitors built from one lot of polycarbonate film. The samples from this lot accounted for 25 percent of the total test complement. Analyses of failed samples showed that the film had an excessive solvent content. This solvent problem was found in 37 of the total 46 failures which occurred in this test. The other nine were random failures resulting from causes such as seal leaks, foreign particles, and possibly wrinkles.

  16. Final Report for the Advanced Camera for Surveys (ACS)

    Science.gov (United States)

    2004-01-01

    ACS was launched aboard the Space Shuttle Columbia just before dawn on March 1, 2002. At the time of liftoff, the Hubble Space Telescope (HST) was reflecting the early morning sun as it moved across the sky. After successfully docking with HST, several components were replaced. One of the components was the Advanced Camera for Surveys built by Ball Aerospace & Technologies Corp. (BATC) in Boulder, Colorado. Over the life of the HST contract at BATC, hundreds of employees had the pleasure of working on the concept, design, fabrication, assembly, and test of ACS. Those employees thank NASA - Goddard Space Flight Center and the science team at Johns Hopkins University (JHU) for the opportunity to participate in building a great science instrument for HST.

  17. Total loss of AC power analysis for EPR reactor

    Energy Technology Data Exchange (ETDEWEB)

    Darnowski, Piotr, E-mail: piotr.darnowski@itc.pw.edu.pl [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); Skrzypek, Eleonora, E-mail: eleonora.skrzypek@ncbj.gov.pl [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); National Centre for Nuclear Research (NCBJ), A. Sołtana 7, 05-400 Otwock-Świerk (Poland); Mazgaj, Piotr, E-mail: piotr.mazgaj@itc.pw.edu.pl [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); Świrski, Konrad [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); Gandrille, Pascal [AREVA NP SAS, Tour AREVA, 1 place Jean Millier, 92084 Paris La Défense (France)

    2015-08-15

    Highlights: • Total loss of AC power (Station Blackout) was simulated for the EPR reactor model. • In-vessel phase of the accident is under consideration. • Comparison of MELCOR and MAAP results is presented. • MELCOR and MAAP results are comparable. - Abstract: In this paper the results of severe accident simulations for the EPR reactor in the case of loss of offsite power combined with total failure of all diesel generators (total loss of AC power) are presented. Calculations were performed with MELCOR 2.1 computer code for in-vessel phase of the accident. In this scenario, the unavailability of all offsite and onsite power sources and the lack of cooling leads directly to core degradation, material relocation to the lower plenum and rupture of the reactor pressure vessel. MELCOR results were compared qualitatively and quantitatively with MAAP4 code results and show a good agreement.

  18. SNL software manual for the ACS Data Analytics Project.

    Energy Technology Data Exchange (ETDEWEB)

    Stearley, Jon R.; McLendon, William Clarence, III; Rodrigues, Arun F.; Williams, Aaron S.; Hooper, Russell Warren; Robinson, David Gerald; Stickland, Michael G.

    2011-10-01

    In the ACS Data Analytics Project (also known as 'YumYum'), a supercomputer is modeled as a graph of components and dependencies, jobs and faults are simulated, and component fault rates are estimated using the graph structure and job pass/fail outcomes. This report documents the successful completion of all SNL deliverables and tasks, describes the software written by SNL for the project, and presents the data it generates. Readers should understand what the software tools are, how they fit together, and how to use them to reproduce the presented data and additional experiments as desired. The SNL YumYum tools provide the novel simulation and inference capabilities desired by ACS. SNL also developed and implemented a new algorithm, which provides faster estimates, at finer component granularity, on arbitrary directed acyclic graphs.

  19. Effective nonlinear AC response to composite with spherical particles

    Institute of Scientific and Technical Information of China (English)

    Chen Xiao-Gang; Liang Fang-Chu; Wei En-Bo

    2005-01-01

    An effective nonlinear alternative-current (AC) response to granular nonlinear-composite with spherical inclusions embedded in a host medium under the action of an external AC field is investigated by using a perturbation approach.The local potentials of composite at higher harmonics are derived both in a region of local inclusion particles and in a local host region under the action of a sinusoidal field E1 sinωt + E3sin3ωt. An effective nonlinear-response to composite and the relationship between the effective nonlinear-responses at the fundamental frequency and the third harmonics are also studied for the spherical inclusions in a dilute limit.

  20. Strongly nonlinear dynamics of electrolytes in large ac voltages

    CERN Document Server

    Olesen, Laurits H; Bruus, Henrik

    2009-01-01

    We study the response of a model micro-electrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider the simplest possible model of a symmetric binary electrolyte confined between parallel-plate blocking electrodes, ignoring any transverse instability or fluid flow. We analyze the resulting one-dimensional problem by matched asymptotic expansions in the limit of thin double layers and extend previous work into the strongly nonlinear regime, which is characterized by two novel features - significant salt depletion in the electrolyte near the electrodes and, at very large voltage, the breakdown of the quasi-equilibrium structure of the double layers. The former leads to the prediction of "ac capacitive desalination", since there is a time-averaged transfer of salt from the bulk to the double layers, via oscillating diffusion layers. The latter is associated with transient diffusion limitation, which drives the formation and co...

  1. Low power DCVSL circuits employing AC power supply

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In view of changing the type of energy conversion in CMOS circuits, this paper investigates low power CMOS circuit design, which adopts a gradually changing power clock. First, we discuss the algebraic expressions and the corresponding properties of clocked power signals. Then the design procedure is summed up for converting complementary CMOS logic gates employing DC power to the power-clocked CMOS gates employing AC power. On this basis, the design of differential cascode voltage switch logic (DCVSL) circuits employing AC power clocks is proposed. The PSPICE simulations using a sinusoidal power-clock demonstrate that the designed power-clocked DCVSL circuit has a correct logic function and low power characteristics. Finally, an interface circuit to convert clocked signals into the standard logic levels of a CMOS circuit is proposed, and its validity is verified by computer simulations.

  2. [Effect of prostatilen AC suppositories on course of experimental prostatitis].

    Science.gov (United States)

    Savateeva-Liubimova, T N; Sivak, K V; Malinin, V V

    2012-01-01

    The article presents the results of evaluation of efficacy of new drug prostatilen AC (rectal suppositories), containing regulatory peptides of the bovine prostate and zinc arginate-glycinate complex, in the treatment of prostatitis. The experiment was conducted on 40 Sprague-Dawley rats weighing 180-200 g. Chronic prostatitis was modeled by injection of 10% Dimexidum in combination with water, mixed with turpentine, a volumetric ratio of 4:1. It is shown that prostatilen AC has pronounced organotropic antiinflammatory effect, which manifests in reducing the weight of the prostate, reducing the protein level in the urine, activity of acid phosphatase, and levels of ceruloplasmin and C-reactive protein. In addition, this drug normalizes the act of urination and increases the diurnal diuresis, has antioxidant properties and increases the blood level of the male sex hormone testosterone.

  3. On-Chip AC self-test controller

    Science.gov (United States)

    Flanagan, John D.; Herring, Jay R.; Lo, Tin-Chee

    2009-09-29

    A system for performing AC self-test on an integrated circuit that includes a system clock for normal operation is provided. The system includes the system clock, self-test circuitry, a first and second test register to capture and launch test data in response to a sequence of data pulses, and a logic circuit to be tested. The self-test circuitry includes an AC self-test controller and a clock splitter. The clock splitter generates the sequence of data pulses including a long data capture pulse followed by an at speed data launch pulse and an at speed data capture pulse followed by a long data launch pulse. The at speed data launch pulse and the at speed data capture pulse are generated for a common cycle of the system clock.

  4. Photovoltaic Inverter Controllers Seeking AC Optimal Power Flow Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Dall' Anese, Emiliano; Dhople, Sairaj V.; Giannakis, Georgios B.

    2016-07-01

    This paper considers future distribution networks featuring inverter-interfaced photovoltaic (PV) systems, and addresses the synthesis of feedback controllers that seek real- and reactive-power inverter setpoints corresponding to AC optimal power flow (OPF) solutions. The objective is to bridge the temporal gap between long-term system optimization and real-time inverter control, and enable seamless PV-owner participation without compromising system efficiency and stability. The design of the controllers is grounded on a dual ..epsilon..-subgradient method, while semidefinite programming relaxations are advocated to bypass the non-convexity of AC OPF formulations. Global convergence of inverter output powers is analytically established for diminishing stepsize rules for cases where: i) computational limits dictate asynchronous updates of the controller signals, and ii) inverter reference inputs may be updated at a faster rate than the power-output settling time.

  5. Control of the LHC 400 MHz RF System (ACS)

    CERN Document Server

    Arnaudon, L; Maesen, P; Prax, M

    2004-01-01

    The LHC ACS RF system is composed of 16 superconducting cavities, eight per ring. Each ring has two cryomodules, each containing four cavities. Each cavity is powered by a 300 kW klystron. The klystrons are grouped in fours, the klystrons in each group sharing a common 58 kV power converter and HV equipment bunker. The ACS RF control system is based on modern industrial programmable controllers (PLCs). A new fast interlock and alarm system with inbuilt diagnostics has been developed. Extensive use of the FIPIO Fieldbus drastically decreases the cabling complexity and brings improved signal quality, increased reliability and easier maintenance. Features of the implementation, such as system layout, communication and the high-level software interface are described. Operational facilities such as the automatic switch on procedure are described, as well as the necessary specialist tools and interfaces. A complete RF chain, including high voltage, cryomodule and klystron is presently being assembled in order to ch...

  6. Small-Signal Analysis of Single-Phase and Three-phase DC/AC and AC/DC PWM Converters with the Frequency-Shift Technique

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Aquila, A. Dell’; Liserre, Marco;

    2004-01-01

    A systematic approach to study dc/ac and ac/dc converters without the use of synchronous transformation is proposed. The use of a frequency-shift technique allows a straightforward analysis of single-phase and three-phase systems. The study of dc/ac and of ac/dc converters is reported to the study...... of dc/dc converters via a 50 Hz frequency-shift. The input admittance is calculated and measured for two study examples (a three-phase active rectifier and a single-phase photovoltaic inverter). These examples show that the purpose of a well designed controller for grid-connected converters...

  7. Challenges and solutions in medically managed ACS in the Asia-Pacific region: expert recommendations from the Asia-Pacific ACS Medical Management Working Group.

    Science.gov (United States)

    Huo, Yong; Thompson, Peter; Buddhari, Wacin; Ge, Junbo; Harding, Scott; Ramanathan, Letchuman; Reyes, Eugenio; Santoso, Anwar; Tam, Li-Wah; Vijayaraghavan, Govindan; Yeh, Hung-I

    2015-03-15

    Acute coronary syndromes (ACS) remain a leading cause of mortality and morbidity in the Asia-Pacific (APAC) region. International guidelines advocate invasive procedures in all but low-risk ACS patients; however, a high proportion of ACS patients in the APAC region receive solely medical management due to a combination of unique geographical, socioeconomic, and population-specific barriers. The APAC ACS Medical Management Working Group recently convened to discuss the ACS medical management landscape in the APAC region. Local and international ACS guidelines and the global and APAC clinical evidence-base for medical management of ACS were reviewed. Challenges in the provision of optimal care for these patients were identified and broadly categorized into issues related to (1) accessibility/systems of care, (2) risk stratification, (3) education, (4) optimization of pharmacotherapy, and (5) cost/affordability. While ACS guidelines clearly represent a valuable standard of care, the group concluded that these challenges can be best met by establishing cardiac networks and individual hospital models/clinical pathways taking into account local risk factors (including socioeconomic status), affordability and availability of pharmacotherapies/invasive facilities, and the nature of local healthcare systems. Potential solutions central to the optimization of ACS medical management in the APAC region are outlined with specific recommendations.

  8. Ac Synchronous Servo Based On The Armature Voltage Prediction Model

    Science.gov (United States)

    Hoshino, Akihiro; Kuromaru, Hiroshi; Kobayashi, Shinichi

    1987-10-01

    A new control method of the AC synchro-nous servo-system (Brushless DC servo-system) is discussed. The new system is based on the armature voltage prediction model. Without a resolver-digital-conver-ter nor a tachometer-generator, the resolver provides following three signals to the system immediately, they are the current command, the induced voltage, and the rotor speed. The new method realizes a simple hardware configuration. Experimental results show a good performance of the system.

  9. Effective AC needleless and collectorless electrospinning for yarn production.

    Science.gov (United States)

    Pokorny, P; Kostakova, E; Sanetrnik, F; Mikes, P; Chvojka, J; Kalous, T; Bilek, M; Pejchar, K; Valtera, J; Lukas, D

    2014-12-28

    Nanofibrous materials are essential components for a wide range of applications, particularly in the fields of medicine and material engineering. These include protective materials, sensors, cosmetics, hygiene, filtration and energy storage. The most widely used and researched technology in these fields is electrospinning. This method for producing fibers yields highly promising results thanks to its versatility and simplicity. Electrospinning is employed in multiple forms, among which needle and needleless direct current (DC) variants are the most distinctive. The former is based on the generation of just one single jet from a nozzle; hence this fabrication process is not very productive. The latter uses the destabilization of free liquid surfaces by means of an electric field, which enhances the throughput since it produces numerous jets, emitted from the surfaces of rollers, spheres, strings and spirals. However, although some progress in total producibility has been achieved, the efficiency of the DC method still remains relatively low. A further drawback of DC electrospinning is that both variants need a collector, which makes it difficult to combine DC electrospinning easily with other technologies due to the presence of the high field strength within the entire spinning zone. This paper describes our experiments with AC electrospinning. We show that alternating current (AC) electrospinning based on a needleless spinning-electrode provides a highly productive smoke-like aerogel composed of nanofibers. This aerogel rises rapidly from the electrode like a thin plume of smoke, without any need for a collector. Our work shows that AC needleless electrospinning gains its efficiency and collector-less feature thanks to the creation of a perpetually charge-changing virtual counter-electrode composed of the nanofibers emitted. High-speed camera recordings demonstrate the formation mechanism of the nanofibrous plume, which is wafted by an electric wind. This wind

  10. Offshore windfarm connection with low frequency AC transmission technology

    DEFF Research Database (Denmark)

    Qin, Nan; Xu, Zhao; You, Shi

    2009-01-01

    This paper investigates the feasibility of using the low frequency AC transmission (LFAC) system, e.g. fraction of 50 Hz or 60 Hz, for connecting the large offshore wind farm to the grid by modelling and simulation. The LFAC system improves the transmission capacity and distance compared to the c...... to the reduced inductive reactance of the grid. Moreover, the harmonics introduced by the frequency converter may require extra filters to be installed in such system....

  11. Transient Temperature Analysis for Industrial AC Arc Furnace Bottom

    Institute of Scientific and Technical Information of China (English)

    (U)nal (C)amdal1; Murat Tun(c)

    2004-01-01

    Heat losses from the furnaces depend on the design and size. The surface heat loss from the bottom of an industrial AC electric arc furnace (EAF) possesses an important fraction of overall losses. So in this study the transient temperature variation at the bottom of the EAF was investigated. The transient temperature analysis was carried out using MATLAB computer program. T=T(r, t) for different bottom lining layers was depicted.

  12. MD 349: Impedance Localization with AC-dipole

    CERN Document Server

    Biancacci, Nicolo; Metral, Elias; Salvant, Benoit; Papotti, Giulia; Persson, Tobias Hakan Bjorn; Tomas Garcia, Rogelio; CERN. Geneva. ATS Department

    2016-01-01

    The purpose of this MD is to measure the distribution of the transverse impedance of the LHC by observing the phase advance variation with intensity between the machine BPMs. Four injected bunches with different intensities are excited with an AC dipole and the turn by turn data is acquired from the BPM system. Through post-processing analysis the phase variation along the machine is depicted and, from this information, first conclusions of the impedance distribution can be drawn.

  13. Cardiovascular Biomarkers in ACS: State of the Art 2012

    OpenAIRE

    Giannitsis, Evangelos; Katus, Hugo A.

    2013-01-01

    In the setting of an acute coronary syndrome cardiac troponins are well established for the diagnosis of myocardial infarction. In particular, diagnostic protocols using high-sensitivity troponin assays are being recommended for earlier diagnosis of MI by the European Society of Cardiology (ESC) guidelines on the management of ACS without ST segment elevation. In addition to accurate detection of myocardial necrosis, cardiac troponins give complementary information on short- and long-term pro...

  14. Measuring System of Magnetostriction Under AC Excitation Using Optical Methods

    OpenAIRE

    Nakase, Tomoya; Nakano, Masanori; Fujiwara, F.; TAKAHASHI, N

    1998-01-01

    A measuring system for magnetostriction of silicon steel sheet using optical methods and a single sheet tester has been developed to establish a standard test method for IEC and JIS. Various factors affecting measurement accuracy and reproducibility of the developed system are examined. Two optical instruments, such as a laser Doppler vibrometer and a heterodyne displacement meter, are compared. 3-D characteristics of magnetostriction under ac excitation in the rolling direction are measured ...

  15. AC system stabilization via phase shift transformer with thyristor commutation

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Jose Carlos de; Guimaraes, Geraldo Caixeta; Moraes, Adelio Jose [Uberlandia Univ., MG (Brazil); Abreu, Jose Policarpo G. de [Escola Federal de Engenharia de Itajuba, MG (Brazil); Oliveira, Edimar Jose de [Juiz de Fora Univ., MG (Brazil)

    1994-12-31

    This article aims to present initially the constructive and operative forms of a phase-shift autotransformer which provides both magnitude and phase angle change through thyristor commutation, including a technic to reduce the number of thyristors. Following, it is proposed a control system to make such equipment an efficient AC system stabilizing tool. It is presented some simulation results to show the operation of this transformer in an electrical system. (author) 3 refs., 11 figs., 3 tabs.

  16. Ac/Ds-induced chromosomal rearrangements in rice genomes.

    Science.gov (United States)

    Xuan, Yuan Hu; Zhang, Jianbo; Peterson, Thomas; Han, Chang-Deok

    2012-03-01

    A closely-linked pair of Ac/Ds elements induces chromosomal rearrangements in Arabidopsis and maize. This report summarizes the Ac/Ds systems that generate an exceptionally high frequency of chromosomal rearrangements in rice genomes. From a line containing a single Ds element inserted at the OsRLG5 locus, plants containing a closely-linked pair of inversely-oriented Ds elements were obtained at 1% frequency among the population regenerated from tissue culture. Subsequent regeneration of the lines containing cis-paired Ds elements via tissue culture led to a high frequency (35.6%) of plants containing chromosomal rearrangements at the OsRLG5 locus. Thirty-four rearrangement events were characterized, revealing diverse chromosomal aberrations including deletions, inversions and duplications. Many rearrangements could be explained by sister chromatid transposition (SCT) and homologous recombination (HR), events previously demonstrated in Arabidopsis and maize. In addition, novel events were detected and presumably generated via a new alternative transposition mechanism. This mechanism, termed single chromatid transposition (SLCT), resulted in juxtaposed inversions and deletions on the same chromosome. This study demonstrated that the Ac/Ds system coupled with tissue culture-mediated plant regeneration could induce higher frequencies and a greater diversity of chromosomal rearrangements than previously reported. Understanding transposon-induced chromosomal rearrangements can provide new insights into the relationship between transposable elements and genome evolution, as well as a means to perform chromosomal engineering for crop improvement. Rice is a staple cereal crop worldwide. Complete genome sequencing and rich genetic resources are great advantages for the study of the genomic complexity induced by transposable elements.(1) (-) (2) The combination of tissue culture with genetic lines carrying a pair of closely located Ac/Ds elements greatly increases the

  17. Prototipo acústico adaptable. Para espacios multifuncionales

    Directory of Open Access Journals (Sweden)

    Constanza Ipinza Olatte

    2017-04-01

    Full Text Available Este artículo presenta la primera etapa de la investigación “Prototipo Acústico Adaptable –para espacios multifuncionales–”, desarrollado en la Escuela de Arquitectura de la Universidad de Santiago de Chile. El objetivo de ella ha sido diseñar y construir un dispositivo de geometría articulada que permita calibrar la acústica del espacio, en función de las necesidades de recepción de los usuarios. Se revisa la base teórica de la propuesta a partir del concepto de arquitectura líquida, que en su fundamentación pretende incorporar la dimensión dinámica del tiempo en la condición material de los espacios. Asimismo, se examina el término acústica variable, que aborda técnicamente la versatilidad del acontecimiento sonoro en un despliegue de técnicas activas o pasivas. Luego se presenta la metodología a través del diseño, basada en el modelo propuesto por Lucien Blessing, que formula un proceso desde la definición de los criterios, hasta la concreción formal del diseño en la construcción del modelo. Finalmente, se presentan los parámetros de validación del diseño que apuntan a la prosecución de su desarrollo en una segunda etapa. En ella, el objetivo será optimizar el modelo y mejorar las transformaciones del ambiente acústico material, espacial y temporal, como se ha propuesto.

  18. Opaciniols A-C, new terpenoids from Garcinia opaca.

    Science.gov (United States)

    Mori, Reika; Nugroho, Alfarius Eko; Hirasawa, Yusuke; Wong, Chin Piow; Kaneda, Toshio; Shirota, Osamu; Hadi, A Hamid A; Morita, Hiroshi

    2014-01-01

    Three new terpenoids, opaciniols A-C (1-3), were isolated from the barks of Garcinia opaca, together with malabarica-17,21-dien-3β,14-diol (4) and 13βH-malabarica-14,17,21-trien-3β-ol (5). Their structures were determined on the basis of NMR spectroscopic data. 3 and 4 showed moderate cytotoxicity against HL-60 cells.

  19. A Novel Protection Scheme against Fault Resistance for AC Microgrid

    Directory of Open Access Journals (Sweden)

    Xinrui Liu

    2017-01-01

    Full Text Available The faults characteristics of the lines in AC microgrid are weakened due to the fault resistance, which may refuse protection action. To solve the problems caused by different types of the faults through fault resistance (FTFR, the faults where the fault point resistance is greater than zero in AC microgrid, a novel FTFR protection scheme based on the active power of 0-frame component or d-frame component consumed by fault resistance is proposed in this paper as the backup protection of FTFR. This proposed protection scheme utilizes the active power of 0-frame component or d-frame component consumed by fault resistance to identify internal FTFR and external faults. It performs well in grid-connected mode and islanded mode by adopting self-adaptive threshold and is not affected by the factors such as the fault position and the fault resistance value. The theoretical analysis and various simulations show that this protection scheme can identify and isolate different types of internal FTFR in AC microgrid with high reliability and high sensitivity.

  20. The ACS-NUCL Division 50th Anniversary: Introduction

    Energy Technology Data Exchange (ETDEWEB)

    Hobart, David E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-10

    The ACS Division of Nuclear Chemistry and Technology was initiated in 1955 as a subdivision of the Division of Industrial and Engineering Chemistry. Probationary divisional status was lifted in 1965. The Division’s first symposium was held in Denver in 1964 and it is fitting that we kicked-off the 50th Anniversary in Denver in the spring of 2015. Listed as a small ACS Division with only about 1,000 members, NUCL’s impact over the past fifty years has been remarkable. National ACS meetings have had many symposia sponsored or cosponsored by NUCL that included Nobel Laureates, U.S. Senators, other high-ranking officials and many students as speakers. The range of subjects has been exceptional as are the various prestigious awards established by the Division. Of major impact has been the past 30 years of the NUCL Nuclear Chemistry Summer Schools to help fill the void of qualified nuclear scientists and technicians. In celebrating the 50th Anniversary we honor the past, celebrate the present and shape the future of the Division and nuclear science and technology. To celebrate this auspicious occasion a commemorative lapel pin has been designed for distribution to NUCL Division members.

  1. Effects of AC Electric Field on Small Laminar Nonpremixed Flames

    KAUST Repository

    Xiong, Yuan

    2015-04-01

    Electric field can be a viable method in controlling various combustion properties. Comparing to traditional actuators, an application of electric field requires very small power consumption. Especially, alternating current (AC) has received attention recently, since it could modulate flames appreciably even for the cases when direct current (DC) has minimal effects. In this study, the effect of AC electric fields on small coflow diffusion flames is focused with applications of various laser diagnostic techniques. Flow characteristics of baseline diffusion flames, which corresponds to stationary small coflow diffusion flames when electric field is not applied, were firstly investigated with a particular focus on the flow field in near-nozzle region with the buoyancy force exerted on fuels due to density differences among fuel, ambient air, and burnt gas. The result showed that the buoyancy force exerted on the fuel as well as on burnt gas significantly distorted the near-nozzle flow-fields. In the fuels with densities heavier than air, recirculation zones were formed very close to the nozzle exit. Nozzle heating effect influenced this near-nozzle flow-field particularly among lighter fuels. Numerical simulations were also conducted and the results showed that a fuel inlet boundary condition with a fully developed velocity profile for cases with long fuel tubes should be specified inside the fuel tube to obtain satisfactory agreement in both the flow and temperature fields with those from experiment. With sub-critical AC applied to the baseline flames, particle image velocimetry (PIV), light scattering, laser-induced incandescence (LII), and laser-induced fluores- cence (LIF) techniques were adopted to identify the flow field and the structures of OH, polycyclic aromatic hydrocarbons (PAHs), soot zone. Under certain AC condi- tions of applied voltage and frequency, the distribution of PAHs and the flow field near the nozzle exit were drastically altered from the

  2. AC Conductivity and Dielectric Properties of Borotellurite Glass

    Science.gov (United States)

    Taha, T. A.; Azab, A. A.

    2016-10-01

    Borotellurite glasses with formula 60B2O3-10ZnO-(30 - x)NaF- xTeO2 ( x = 0 mol.%, 5 mol.%, 10 mol.%, and 15 mol.%) have been synthesized by thermal melting. X-ray diffraction (XRD) analysis confirmed that the glasses were amorphous. The glass density ( ρ) was determined by the Archimedes method at room temperature. The density ( ρ) and molar volume ( V m) were found to increase with increasing TeO2 content. The direct-current (DC) conductivity was measured in the temperature range from 473 K to 623 K, in which the electrical activation energy of ionic conduction increased from 0.27 eV to 0.48 eV with increasing TeO2 content from 0 mol.% to 15 mol.%. The dielectric parameters and alternating-current (AC) conductivity ( σ ac) were investigated in the frequency range from 1 kHz to 1 MHz and temperature range from 300 K to 633 K. The AC conductivity and dielectric constant decreased with increasing TeO2 content from 0 mol.% to 15 mol.%.

  3. AC electrokinetic manipulation of selenium nanoparticles for potential nanosensor applications

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoodi, Seyed Reza [School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Bayati, Marzieh, E-mail: m-bayati@tums.ac.ir [School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Hosseinirad, Somayeh [School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Foroumadi, Alireza [Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Gilani, Kambiz [Department of Pharmaceutics, School of Pharmacy, Tehran University of Medical Science, Tehran (Iran, Islamic Republic of); Rezayat, Seyed Mahdi [School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2013-03-15

    Highlights: ► Se nanoparticles were synthesized using a reverse-microemulsion process. ► AC osmotic fluid flow repulses the particles from electrode edges. ► Dielectrophoretic force attracts the particles to electrode edges. ► Dielectrophoresis electrode showed non-ohmic behavior. ► The device can potentially be used as a nanosensor. - Abstract: We report the AC electrokinetic behavior of selenium (Se) nanoparticles for electrical characterization and possible application as micro/nano devices. selenium Se nanoparticles were successfully synthesized using a reverse-microemulsion process and investigated structurally using X-ray diffraction and transmission electron microscope. Interdigitated castellated ITO and non-castellated platinum electrodes were employed for manipulation of suspended materials in the fluid. Using ITO electrodes at low frequency limits resulted in deposition of Se particles on electrode surface. When Se particles exposed to platinum electrodes in the 10 Hz–1 kHz range and V {sub p−p}> 8, AC osmotic fluid flow repulses the particles from electrode edges. However, in 10 kHz–10 MHz range and V {sub p−p}> 5, dielectrophoretic force attracts the particles to electrode edges. As the Se particle concentration increased, the trapped Se particles were aligned along the electric field line and bridged the electrode gap. The device was characterized and can potentially be useful in making micro/nano electronic devices.

  4. AC electric field induced vortex in laminar coflow diffusion flames

    KAUST Repository

    Xiong, Yuan

    2014-09-22

    Experiments were performed by applying sub-critical high-voltage alternating current (AC) to the nozzle of laminar propane coflow diffusion flames. Light scattering, laser-induced incandescence and laser-induced fluorescence techniques were used to identify the soot zone, and the structures of OH and polycyclic aromatic hydrocarbons (PAHs). Particle image velocimetry was adopted to quantify the velocity field. Under certain AC conditions of applied voltage and frequency, the distribution of PAHs and the flow field near the nozzle exit were drastically altered, leading to the formation of toroidal vortices. Increased residence time and heat recirculation inside the vortex resulted in appreciable formation of PAHs and soot near the nozzle exit. Decreased residence time along the jet axis through flow acceleration by the vortex led to a reduction in the soot volume fraction in the downstream sooting zone. Electromagnetic force generated by AC was proposed as a viable mechanism for the formation of the toroidal vortex. The onset conditions for the vortex formation supported the role of an electromagnetic force acting on charged particles in the flame zone. (C) 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

  5. New Subarray Readout Patterns for the ACS Wide Field Channel

    Science.gov (United States)

    Golimowski, D.; Anderson, J.; Arslanian, S.; Chiaberge, M.; Grogin, N.; Lim, Pey Lian; Lupie, O.; McMaster, M.; Reinhart, M.; Schiffer, F.; Serrano, B.; Van Marshall, M.; Welty, A.

    2017-04-01

    At the start of Cycle 24, the original CCD-readout timing patterns used to generate ACS Wide Field Channel (WFC) subarray images were replaced with new patterns adapted from the four-quadrant readout pattern used to generate full-frame WFC images. The primary motivation for this replacement was a substantial reduction of observatory and staff resources needed to support WFC subarray bias calibration, which became a new and challenging obligation after the installation of the ACS CCD Electronics Box Replacement during Servicing Mission 4. The new readout patterns also improve the overall efficiency of observing with WFC subarrays and enable the processing of subarray images through stages of the ACS data calibration pipeline (calacs) that were previously restricted to full-frame WFC images. The new readout patterns replace the original 512×512, 1024×1024, and 2048×2046-pixel subarrays with subarrays having 2048 columns and 512, 1024, and 2048 rows, respectively. Whereas the original square subarrays were limited to certain WFC quadrants, the new rectangular subarrays are available in all four quadrants. The underlying bias structure of the new subarrays now conforms with those of the corresponding regions of the full-frame image, which allows raw frames in all image formats to be calibrated using one contemporaneous full-frame "superbias" reference image. The original subarrays remain available for scientific use, but calibration of these image formats is no longer supported by STScI.

  6. Design and development of the Army KE ASAT ACS thruster

    Science.gov (United States)

    Craddock, Jeff; Janeski, Bruce

    1993-06-01

    Increasingly ambitious missions for advanced kinetic energy (KE) weapons have necessitated the development of a lightweight storable-propellant attitude control system (ACS) thruster capable of very fast response and long duration firings. This paper summarizes the results of a ACS thruster design and development test effort, performed for the U.S. Army Space and Strategic Defense Command (USASSDC) on the KE Anti Satellite (KE ASAT) weapon system program. Design approaches used to achieve long-duration continuous firing with a composite combustion chamber are detailed. This design effort culminated in a 6.7 lbf. thruster assembly weighing less than 0.2 pounds, approximately one-sixth that of a conventional satellite ACS thruster. Results of tests of flightweight engines with nitrogen tetroxide and monomethyl hydrazine hypergolic propellants are included. The test series culminated in what is believed to be the industry's longest continuous firing of a composite combustion chamber. This thruster will be integrated into the KE ASAT kinetic vehicle for its first free-flight hover test in early FY94. The demonstrated fast response, high pulse performance, and long-duration capabilities of this engine suggest that this thruster can significantly increase the capability of other spacecraft.

  7. Working with the American Community Survey in R a guide to using the acs package

    CERN Document Server

    Glenn, Ezra Haber

    2016-01-01

    This book serves as a hands-on guide to the "acs" R package for demographers, planners, and other researchers who work with American Community Survey (ACS) data. It gathers the most common problems associated with using ACS data and implements functions as a package in the R statistical programming language. The package defines a new "acs" class object (containing estimates, standard errors, and metadata for tables from the ACS) with methods to deal appropriately with common tasks (e.g., creating and combining subgroups or geographies, automatic fetching of data via the Census API, mathematical operations on estimates, tests of significance, plots of confidence intervals).

  8. Production of AC-225 and application of the BI-213 daughter in cancer therapy

    Science.gov (United States)

    Koch, L.; Apostolidis, C.; Janssens, W.; Molinet, R.; van Geel, J.

    1999-01-01

    There are several ongoing medical trials to use Bi-213 conjugated to monoclonal antibodies to kill tumour-cells of various cancer types. The institute is supplying Ac-225 generators for the test and is itself engaged in in-vitro cytotoxicity tests. Nuclear reactions leading to Ac-225 are discussed. The present supply of Ac-225 stems from Th-229 decay obtained from aged U-233. From the possible alternative the reactions Ra-226 (p, 2n) Ac-225 is presently favoured. The fabrication of a Ac-225 for Bi-213 generator will be described.

  9. Relations between ac-dc components and optical path length in photoplethysmography

    Science.gov (United States)

    Lee, Chungkeun; Sik Shin, Hang; Lee, Myoungho

    2011-07-01

    Photoplethysmography is used in various areas such as vital sign measurement, vascular characteristics analysis, and autonomic nervous system assessment. Photoplethysmographic signals are composed of ac and dc, but it is difficult to find research about the interaction of photoplethysmographic components. This study suggested a model equation combining two Lambert-Beer equations at the onset and peak points of photoplethysmography to evaluate ac characteristics, and verified the model equation through simulation and experiment. In the suggested equation, ac was dependent on dc and optical path length. In the simulation, dc was inversely proportionate to ac sensitivity (slope), and ac and optical path length were proportionate. When dc increased from 10% to 90%, stabilized ac decreased from 1 to 0.89 +/- 0.21, and when optical path length increased from 10% to 90%, stabilized ac increased from 1 to 1.53 +/- 0.40.

  10. 144例近视患者AC/A值与近视处方

    Institute of Scientific and Technical Information of China (English)

    贾宝轩

    2010-01-01

    目的:研究青少年近视眼与AC/A值的关系,讨论结合AC/A值确定处方的必要性.方法:随机抽取144名10~19岁的患者,进行眼镜全矫,根据屈光度分成6组,然后进行AC/A值的测定.结果:通过AC/A值的比较,可以看出近视眼患者的AC/A值和正常值有差距,而且AC/A平均值随近视度增加有升高的趋势.结论:针对近视患者,在主客观验光的基础上,要结合AC/A检查结果,为患者提供合理的处方.

  11. Phosphor-in-glass for high-powered remote-type white AC-LED.

    Science.gov (United States)

    Lin, Hang; Wang, Bo; Xu, Ju; Zhang, Rui; Chen, Hui; Yu, Yunlong; Wang, Yuansheng

    2014-12-10

    The high-powered alternating current (AC) light-emitting diode (LED) (AC-LED), featuring low cost, high energy utilization efficiency, and long service life, will become a new economic growth point in the field of semiconductor lighting. However, flicker of AC-LED in the AC cycles is not healthy for human eyes, and therefore need to be restrained. Herein we report an innovation of persistent "phosphor-in-glass" (PiG) for the remote-type AC-LED, whose afterglow can be efficiently activated by the blue light. It is experimentally demonstrated that the afterglow decay of PiG in the microsecond range can partly compensate the AC time gap. Moreover, the substitution of inorganic glass for organic resins or silicones as the encapsulants would bring out several technological benefits to AC-LED, such as good heat-dissipation, low glare, and excellent physical/chemical stability.

  12. Reassembled Biosynthetic Pathway for a Large-scale Synthesis of CMP-Neu5Ac

    Directory of Open Access Journals (Sweden)

    Min Xiao

    2003-11-01

    Full Text Available Abstract: CMP-Neu5Ac is an important sugar nucleotide for biosynthesis of sialic acid and its conjugates. In this paper, a large-scale production system of CMP-Neu5Ac by a single strain is reported. The co-expression of Neu5Ac aldolase (EC4.1.3.3 and CMP-Neu5Ac synthetase (EC 2.7.7.43 was achieved by constructing individual genes into one plasmid and having a single culture that has both NeuAc aldolase and CMP-Neu5Ac synthetase activities. Overall this system only employed N-acetylmannosamine, excess of pyruvate and CTP to produce CMP-Neu5Ac. This work has demonstrated that a large-scale synthesis of sialic acid-derived oligosaccharides could be achieved economically and efficiently through a single, biosynthetic pathway engineered microorganism.

  13. The dynamic process of atmospheric water sorption in [EMIM][Ac] and mixtures of [EMIM][Ac] with biopolymers and CO2 capture in these systems.

    Science.gov (United States)

    Chen, Yu; Sun, Xiaofu; Yan, Chuanyu; Cao, Yuanyuan; Mu, Tiancheng

    2014-10-02

    There are mainly three findings related to the dynamic process of atmospheric water sorption in the ionic liquid (IL) 1-ethyl-3-methlyl-imidazolium acetate ([EMIM][Ac]) and its mixtures with biopolymers (i.e., cellulose, chitin, and chitosan), and CO2 capture in these systems above. The analytical methods mainly include gravimetric hygroscopicity measurement and in situ infrared spectroscopy with the techniques of difference, derivative, deconvoluted attenuated total reflectance and two-dimensional correlation. These three findings are listed as below. (1) Pure [EMIM][Ac] only shows a two-regime pattern, while all the mixtures of [EMIM][Ac] with biopolymers (i.e., cellulose, chitin, and chitosan) present a three-regime tendency for the dynamic process of atmospheric water sorption. Specifically, the IL/chitosan mixture has a clear three-regime mode; the [EMIM][Ac]/chitin mixture has an unclear indiscernible regime 3; and the [EMIM][Ac]/cellulose mixture shows an indiscernible regime 2. (2) [EMIM][Ac] and its mixtures with biopolymers could physically absorb a trace amount of and chemically react with a much larger amount of CO2 from the air. The chemisorption capacity of CO2 in these pure and mixed systems is ordered as chitosan/[EMIM][Ac] mixture > chitin/[EMIM][Ac] mixture > cellulose/[EMIM][Ac] mixture > pure [EMIM][Ac] (ca. 0.09 mass ratio % g/g CO2/IL). (3) The CO2 solubility in [EMIM][Ac] decreases about 50% after being exposed to the atmospheric moist air for some specific time period.

  14. Mungbean yellow mosaic virus (MYMV) AC4 suppresses post-transcriptional gene silencing and an AC4 hairpin RNA gene reduces MYMV DNA accumulation in transgenic tobacco.

    Science.gov (United States)

    Sunitha, Sukumaran; Shanmugapriya, Gnanasekaran; Balamani, Veluthambi; Veluthambi, Karuppannan

    2013-06-01

    Mungbean yellow mosaic virus (MYMV) is a legume-infecting geminivirus that causes yellow mosaic disease in blackgram, mungbean, soybean, Frenchbean and mothbean. AC4/C4, which is nested completely within the Rep gene, is less conserved among geminiviruses. Much less is known about its role in viral pathogenesis other than its known role in the suppression of host-mediated gene silencing. Transient expression of MYMV AC4 by agroinfiltration suppressed post-transcriptional gene silencing in Nicotiana benthamiana 16c expressing green fluorescence protein, at a level comparable to MYMV TrAP expression. AC4 full-length gene and an inverted repeat of AC4 (comprising the full-length AC4 sequence in sense and antisense orientations with an intervening intron) which makes a hairpin RNA (hpRNA) upon transcription were introduced into tobacco by Agrobacterium-mediated leaf disc transformation. Leaf discs of the transgenic plants were agroinoculated with partial dimers of MYMV and used to study the effect of the AC4-sense and AC4 hpRNA genes on MYMV DNA accumulation. Leaf discs of two transgenic plants that express the AC4-sense gene displayed an increase in MYMV DNA accumulation. Leaf discs of six transgenic plants containing the AC4 hpRNA gene accumulated small-interfering RNAs (siRNAs) specific to AC4, and upon agroinoculation with MYMV they exhibited a severe reduction in the accumulation of MYMV DNA. Thus, the MYMV AC4 hpRNA gene has emerged as a good candidate to engineer resistance against MYMV in susceptible plants.

  15. Expression Study of LeGAPDH, LeACO1, LeACS1A, and LeACS2 in Tomato Fruit (Solanum lycopersicum

    Directory of Open Access Journals (Sweden)

    Pijar Riza Anugerah

    2015-10-01

    Full Text Available Tomato is a climacteric fruit, which is characterized by ripening-related increase of respiration and elevated ethylene synthesis. Ethylene is the key hormone in ripening process of climacteric fruits. The objective of this research is to study the expression of three ethylene synthesis genes: LeACO1, LeACS1A, LeACS2, and a housekeeping gene LeGAPDH in ripening tomato fruit. Specific primers have been designed to amplify complementary DNA fragment of LeGAPDH (143 bp, LeACO1 (240 bp, LeACS1A (169 bp, and LeACS2 (148 bp using polymerase chain reaction. Nucleotide BLAST results of the complementary DNA fragments show high similarity with LeGAPDH (NM_001247874.1, LeACO1 (NM_001247095.1, LeACS1A(NM_001246993.1, LeACS2 (NM_001247249.1, respectively. Expression study showed that LeACO1, LeACS1A, LeACS2, and LeGAPDH genes were expressed in ripening tomato fruit. Isolation methods, reference sequences, and primers used in this study can be used in future experiments to study expression of genes responsible for ethylene synthesis using quantitative polymerase chain reaction and to design better strategy for controlling fruit ripening in agroindustry.

  16. AcMNPV-mediated expression of BmK IT promotes the apoptosis of Sf9 cells and replication of AcMNPV.

    Science.gov (United States)

    Fu, Yue-Jun; Zhao, Jie; Liang, Ai-Hua; Hu, Feng-Yun

    2015-06-25

    Chinese scorpion Buthus martensii Karsch (BmK) venom is a rich source of neurotoxins which bind to various ion channels with high affinity and specificity and thus widely used as compounds to modulate channel gating or channel currents. To promote the insecticidal effects of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV), the gene encoding an excitatory insect toxin, BmK IT, was inserted into the genome of AcMNPV to construct a recombinant baculovirus, AcMNPV-BmK IT. Spodopter frugiperda 9 (Sf9) cells were infected with AcMNPV and AcMNPV-BmK IT respectively for 24 h. Results from the MTT assay, TUNEL assay, analysis of the expression level of apoptosis-related proteins (c-Myc, cleaved-Caspase3, Bcl-2 and Bax) of Sf9 cells, the transcription level of key genes (38K, C42, P78, F) of AcMNPV, and viral propagation assay demonstrated that AcMNPV-mediated expression of BmK IT promoted the apoptosis of Sf9 cells and replication of AcMNPV. The results laid a foundation for further structural and functional analysis of BmK IT.

  17. New Composites LnBDC@AC and CB[6]@AC: From Design toward Selective Adsorption of Methylene Blue or Methyl Orange

    Science.gov (United States)

    Santos, Guilherme de C.; Barros, Amanda L.; de Oliveira, Carlos A. F.; da Luz, Leonis L.; da Silva, Fausthon F.; Demets, Grégoire J.-F.; Alves Júnior, Severino

    2017-01-01

    New porous composites LnBDC@AC (AC = Activated carbon, Ln = Eu and Gd and BDC = 1,4-benzenedicaboxylate) and CB[6]@AC (CB[6] = Cucurbit[6]uril) were obtained using hydrothermal route. The LnBDC and CB[B] are located inside the pore of the carbon materials as was observed in SEM-EDS, XRPD and FT-IR analysis. Porosimetry analysis showed values typically between AC and LnBDC material, with pore size and surface area, respectively, 29,56 Å and 353.98 m2g-1 for LnBDC@AC and 35,53 Å and 353.98 m2g-1 for CB[6]@AC. Both materials showed good absorptive capacity of metil orange (MO) and methylene blue (MB) with selectivity as a function of pH. For acid pH, both materials present selectivity by MB and alkaline pH for MO, with notable performance for CB[6]@AC. Additionally, europium luminescence was used as structural probe to investigate the coordination environment of Eu3+ ions in the EuBDC@AC composite after adsorption experiment. PMID:28107440

  18. Bacillus thuringiensis delta-endotoxin Cry1Ac domain III enhances activity against Heliothis virescens in some, but not all Cry1-Cry1Ac hybrids

    NARCIS (Netherlands)

    Karlova, R.B.; Weemen, W.M.J.; Naimov, S.; Ceron, J.; Dukiandjiev, S.; Maagd, de R.A.

    2005-01-01

    We investigated the role of domain III of Bacillus thuringiensis d-endotoxin Cry1Ac in determining toxicity against Heliothis virescens. Hybrid toxins, containing domain III of Cry1Ac with domains I and II of Cry1Ba, Cry1Ca, Cry1Da, Cry1Ea, and Cry1Fb, respectively, were created. In this way Cry1Ca,

  19. 新颖的Buck-Boost高频环节AC/AC变换器%Novel Buck-Boost AC/AC Converters with High Frequency Link

    Institute of Scientific and Technical Information of China (English)

    刘剑; 陈道炼; 尹春

    2004-01-01

    提出了Buck-Boost高频环节AC/AC变换器电路拓扑,该电路拓扑由输入周波变换器、高频储能式变压器、输出周波变换器构成.分析研究了该变换器工作模式和电压瞬时值反馈控制策略.理论分析和试验表明,该变换器具有两级功率变换(LFAC/HFAC/LFAC)、双向功率流、网侧电流波形可得到改善、负载适应能力强、音频噪音小等优点.

  20. 77 FR 38375 - Advisory Circular (AC) 150/5345-53D, Airport Lighting Equipment Certification Program; Proposed...

    Science.gov (United States)

    2012-06-27

    ... Federal Aviation Administration Advisory Circular (AC) 150/5345-53D, Airport Lighting Equipment... replace AC150/5345-53C with AC150/5345-53D to clarify the criteria under the Airport Lighting Equipment... Transportation is providing notice in the Federal Register of, and an opportunity for public comment on AC150...

  1. Improvement of cotton fiber quality by transforming the acsA and acsB genes into Gossypium hirsutum L. by means of vacuum infiltration.

    Science.gov (United States)

    Li, X; Wang, X D; Zhao, X; Dutt, Y

    2004-04-01

    A novel method for the genetic transformation of cotton pollen by means of vacuum infiltration and Agrobacterium-mediated transformation is reported. The acsA and acsB genes, which are involved in cellulose synthesis in Acetobacter xylinum, were transferred into pollen grains of brown cotton with the aim of improving its fiber quality by incorporating useful prokaryotic features into the colored cotton plants. Transformation was carried out in cotton pollen-germinating medium, and transformation was mediated by vector pCAMBIA1301, which contains a reporter gene beta-glucuronidase (GUS), a selectable marker gene, hpt, for hygromycin resistance and the genes of interest, acsA and acsB. The integration and expression of acsA, acsB and GUS in the genome of transgenic plants were analyzed with Southern blot hybridization, PCR, histochemical GUS assay and Northern blot hybridization. We found that following pollination on the cotton stigma transformed pollen retained its capability of double-fertilization and that normal cotton seeds were produced in the cotton ovary. Of 1,039 seeds from 312 bolls pollinated with transformed pollen grains, 17 were able to germinate and grow into seedlings for more than 3 weeks in a nutrient medium containing 50 mg/l hygromycin; eight of these were transgenic plants integrated with acsA and acsB, yielding a 0.77% transformation rate. Fiber strength and length from the most positive transformants was 15% greater than those of the control (non-transformed), a significant difference, as was cellulose content between the transformed and control plants. Our study suggests that transformation through vacuum infiltration and Agrobacterium mediated transformation can be an efficient way to introduce foreign genes into the cotton pollen grain and that cotton fiber quality can be improved with the incorporation of the prokaryotic genes acsA and acsB.

  2. Construction and function of recombinant AcMNPV with double copies of v-cath gene

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Two recombinant baculoviruses, dciAcMNPV and dcdAcMNPV in which another copy of the v-cath gene controlled by ie1 promoter and polh promoter was inserted, were respectively constructed by the Bac-to-Bac system. The expression of the v-cath gene of the recombinant baculoviruses in Sf9 cells at different phases was investigated by SDS- PAGE and Western blot. The results showed that only recombinant virus dciAcMNPV containing late gene v-cath driven by early gene promoter could express V-CATH protein, cathepsin encoded by virus genome, 12 h post-infection and dcdAcMNPV containing late gene v-cath driven by late and very late gene promoters could express more V-CATH protein. Negative control ncAcMNPV, a mutant deleted v- cath gene, could not express V-CATH protein at all. The Spodopera exigua larvae were infected with viruses respectively and the results showed that the toxicity was as follows: dcdAcMNPV>dciAcMNPV>wtAcMNPV>ncAcMNPV. The toxicity of recombinant viruses and the characters of dead larvae showed that the v-cath gene was relative to viral toxicity and host liquefaction. Recombinant baculovirus dcdAcMNPV might be used as a new kind of safe viral-pes- ticide, because of its high toxicity obtained by adding another gene copy and changing the expression level of its own gene relative to virulence.

  3. AC-conductance of a non-local Thirring model

    Energy Technology Data Exchange (ETDEWEB)

    Trobo, Marta Liliana; Von Reichenbach, Maria Cecilia [Universidad Nacional de La Plata (UNLP) (Argentina); Barci, Daniel G. [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)]|[Illinois Univ., Urbana, IL (United States); Medeiros Neto, J.F. de [Universidade Estadual de Santa Cruz (UESC), Ilheus, BA (Brazil)

    2000-07-01

    Full text follows: In recent years renewed interest has arisen in the study of low dimensional field theories. In particular, research on the one dimensional (1-d) fermionic gas has been very active, mainly due to the actual nano-fabrication of the so called quantum wires and their relevance for low dimensional condensed matter physics as, for instance, the quantum Hall effect and high-T{sub c} superconductivity. Experimental and theoretical investigations of the AC-transport phenomena in nano-structures are of profound scientific interest since they provide insight into the behavior of quantum systems. In this frame, we consider a field theoretical approach that can be used to describe a system of 1-d strongly correlated particles in the low transferred momentum limit. We study a non-local and non-covariant version of the Thirring model where the fermionic densities and currents are coupled through bilocal, distance-dependent potentials which describe the forward scattering processes. We apply the functional bosonization formalism, a very useful technique to understand the non-perturbative regime of strongly correlated one-dimensional fermionic systems, to this non local Thirring like model (NLTM). We are interesting in the transport properties of the system, in particular in the AC-conductance. To this end, we consider a NLTM in the presence of an external electromagnetic field. We obtain the AC-conductance of the model in terms of non-local potentials used to describe the interactions between fermionic currents. We also analyze the transport properties in the case in which weak couplings between fermionic currents and localized impurities are taken into account. (author)

  4. EFEK MEDAN LISTRIK AC TERHADAP PERTUMBUHAN BAKTERI Klebsiella Pneumoniae

    Directory of Open Access Journals (Sweden)

    Mokhamad Tirono

    2013-05-01

    Full Text Available Penghambatan pertumbuhan bakteri Klebsiella pneumoniai pada ikan kembung dengan medan listrik alternating current (AC telah dilakukan. Medan Listrik AC yang digunakan divariasi dari 0,38 kV/cm sampai 5 kV/cm dengan frekwensi 50 Hz, sedangkan waktu paparan 10 menit. Pada penelitian ini dilakukan penumbuhan bakteri Klebsiella pneumonia pada media NA selama 24 jam dan berikutnya ditumbuhkan pada medium NB dan ikan yang sudah disterilkan selama 24 jam. Bakteri yang sudah ditumbuhkan pada medium NB dan ikan kemudian dipapar dengan medan listrik AC dengan variasi kuat medan yaitu dari 0,38 kV/cm sampai 5 kV/cm dengan waktu paparan 10 menit. Sehabis dipapar bakteri ditumbuhkan pada medium NB selama 24 jam dan berikutnya diencerkan dengan aquades untuk dihitung jumlah koloninya. Hasil uji menggunkan univariate analysis of variance didapatkan nilai signifisi 0,000 yang menunjukkan ada perbedaan yang signifikan untuk masing-masing kuat medan listrik. Menggunakan statistic post hoc test diperoleh bahwa dengan kuat medan 5 kV/cm mempunyai faktor hambat 0,99, sedangkan  dengan  kuat   medan  0,38   kV/cm  mempunyai  faktor   hambat   0,3.   Terhambatnya pertumbuhan bakteri ini disebabkan oleh karena membran seluler bakteri rusak, sehingga menyebabkan keluarnya materi intraseluler. Kerusakan membran seluler disebabkan oleh terjadinya elektroporasi yang dapat meningkatkan potensial membran. Semakin tinggi medan listrik yang dikenakan, maka peningkatan tegangan transmembran semakin tinggi.

  5. AC Motor Drive Fed by Renewable Energy Sources with PWM

    Directory of Open Access Journals (Sweden)

    J. Pavalam

    2014-01-01

    Full Text Available In this fast aproaching nature of technology the ned of Electricity becomes a mandatory in developing technology. The ned of Electricity increases the power demand where the power demand met by the conventional sources of energy has some disadvantage of polution, this disadvantage can be decreased by the use of the Renewable energy sources like Fuel Cel and available solar energy. When a FUEL cel produces AC power, basicaly two stages are required for conversion first a bosting stage and second is inversion stage. In this paper the Bost inverter topology is achieved where in the conventional methods the normal DC - AC power conversion method is used where as in this paper the PWM based DC - AC inverter has ben used which is useful in reducing the harmonics in the output of the Inverter. The voltage controled output is produced in the bost inverter the curent controled output is taken from dc-dc bidirectional converter. The Fuel cel canot be relied as a whole so a Solar PV module is conected acros the Load so while the Sunlight days the PV arays generate power and in the night time the Fuel cel is used to generate power for the load. Since, the Fuel cel and PV arays can generate power in Partial load they are prefered than any other sources. When the output from the Solar PV aray is low or when the sunlight available is not eficient in generating the power a automatic switch over is provided in the junction betwen the Solar PV aray and Fuel cel so that whenever it hapens the switch automaticaly switch over to another source. The simulation results are presented to confirm the operational feature of the proposed system.

  6. Impedance Localization Measurements using AC Dipoles in the LHC

    CERN Document Server

    Biancacci, Nicolo; Papotti, Giulia; Persson, Tobias; Salvant, Benoit; Tomás, Rogelio

    2016-01-01

    The knowledge of the LHC impedance is of primary importance to predict the machine performance and allow for the HL-LHC upgrade. The developed impedance model can be benchmarked with beam measurements in order to assess its validity and limit. This is routinely done, for example, moving the LHC collimator jaws and measuring the induced tune shift. In order to localize possible unknown impedance sources, the variation of phase advance with intensity between beam position monitors can be measured. In this work we will present the impedance localization measurements performed at injection in the LHC using AC dipoles as exciter as well as the underlying theory.

  7. Materials for Powder-Based AC-Electroluminescence

    Directory of Open Access Journals (Sweden)

    Hubert Schulze Dieckhoff

    2010-02-01

    Full Text Available At present, thick film (powder based alternating current electroluminescence (AC-EL is the only technology available for the fabrication of large area, laterally structured and coloured light sources by simple printing techniques. Substrates for printing may be based on flexible polymers or glass, so the final devices can take up a huge variety of shapes. After an introduction of the underlying physics and chemistry, the review highlights the technical progress behind this development, concentrating on luminescent and dielectric materials used. Limitations of the available materials as well as room for further improvement are also discussed.

  8. Unbalanced Voltage Compensation in Low Voltage Residential AC Grids

    DEFF Research Database (Denmark)

    Trintis, Ionut; Douglass, Philip; Munk-Nielsen, Stig

    2016-01-01

    This paper describes the design and test of a control algorithm for active front-end rectifiers that draw power from a residential AC grid to feed heat pump loads. The control algorithm is able to control the phase to neutral or phase to phase RMS voltages at the point of common coupling....... The voltage control was evaluated with either active or reactive independent phase load current control. The control performance in field operation in a residential grid situated in Bornholm, Denmark was investigated for different use cases....

  9. AC dipole based optics measurement and correction at RHIC

    CERN Document Server

    Shen, X; Bai, M; White, S; Robert-Domolaize, G; Luo, Y; Marusic, A; Tomas, R

    2013-01-01

    Independent component analysis (ICA) was applied to the AC dipole based optics measurement at RHIC to extract beta functions as well as phase advances at each BPM. Existence of excessive beta-beat was observed in both rings of RHIC at polarized proton store energy. A unique global optics correction scheme was then developed and tested successfully during the RHIC polarized proton run in 2013. The feasibility of using horizontal closed orbit bump at sextupole for arc beta-beat correction was also demonstrated.

  10. Warning: safety risk with some Apple AC Wall Plug Adapters

    CERN Multimedia

    CERN IT department

    2016-01-01

    Dear Mac and iOS Users, Apple has determined that some of its two prong Apple AC wall plug adapters may break and create a risk of electrical shock.   CERN users can now exchange their affected Apple wall plug adapters at the Service Desk. To find out if your adapter is affected and for any further information concerning the procedure to follow to exchange it, please check the following URL: https://cern.service-now.com/service-portal/view-outage.do?n=OTG0028639.

  11. Kadcotriones A-C: tricyclic triterpenoids from Kadsura coccinea.

    Science.gov (United States)

    Liang, Cheng-Qin; Shi, Yi-Ming; Li, Xing-Yao; Luo, Rong-Hua; Li, Yan; Zheng, Yong-Tang; Zhang, Hong-Bin; Xiao, Wei-Lie; Sun, Han-Dong

    2013-12-27

    Three new triterpenoids, kadcotriones A-C (1-3), together with the biogenetically related lanostane-type triterpenoid (4), were isolated from Kadsura coccinea. Compound 1 features a 12,14β-dimethyl 6/6/6-fused tricyclic skeleton, while 2 and 3 are characterized by a 6/6/5-ring system. Their structures were determined by NMR and electronic circular dichroism spectroscopic methods. Compounds 2 and 4 exhibited anti-HIV-1 activities with EC50 values of 30.29 and 54.81 μM, respectively.

  12. High Voltage AC underground cable systems for power transmission

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Silva, Filipe Miguel Faria da

    2016-01-01

    This paper is a second of two presenting a review of research results in underground cable transmission obtained by the Department of Energy Technology, Aalborg University ET/AAU and Danish TSO Energinet.dk within the last six years. The main core of the results are obtained by PhD students...... researching electrical engineering topics related to using underground cables for power transmission at EHV level and including the 420 kV level. The research topics were laid down by ET/AAU and Energinet.dk in the DANPAC (DANish Power systems with Ac Cables) research project. The main topics are discussed...

  13. Total synthesis and allelopathic activity of cytosporones A-C

    Energy Technology Data Exchange (ETDEWEB)

    Zamberlam, Charles E.M.; Meza, Alisson; Lima, Denis P. de; Beatriz, Adilson [Centro de Ciencias Exatas e Tecnologia, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS (Brazil); Leite, Carla Braga; Marques, Maria Rita [Centro de Ciencias Biologicas e da Saude, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS (Brazil)

    2012-07-01

    The search for efficient, environmentally friendly herbicides has been the focus of numerous studies on the organic synthesis of compounds isolated from natural sources. Cytosporones, which are phenolic lipids isolated from fungi, exhibit noteworthy biological properties. This paper reports the preparation of cytosporones A-C from the same starting material through a short synthetic route, with good yields. All compounds were tested for allelopathic activity on lettuce (Lactuca sativa L) seeds. Cytosporone A and its methylated precursor showed remarkable allelopathic activity, inhibiting seed germination and plantule growth. (author)

  14. A Multi-channel AC Power Supply Controller

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A multi-channel AC power Supply controler developed recently by us was introdueed briefty in this paper.This controller is a computer controlled multi-electronic-switch device.The controller contains 16 independent channels in a standard box(440W×405D×125H mm).There is an electronic switch in each channel,the rated load power is≤1 kW.The main function of the controller is to set the state of electronic switch(ON/OFF)

  15. Power Electronic Transformer based Three-Phase PWM AC Drives

    Science.gov (United States)

    Basu, Kaushik

    A Transformer is used to provide galvanic isolation and to connect systems at different voltage levels. It is one of the largest and most expensive component in most of the high voltage and high power systems. Its size is inversely proportional to the operating frequency. The central idea behind a power electronic transformer (PET) also known as solid state transformer is to reduce the size of the transformer by increasing the frequency. Power electronic converters are used to change the frequency of operation. Steady reduction in the cost of the semiconductor switches and the advent of advanced magnetic materials with very low loss density and high saturation flux density implies economic viability and feasibility of a design with high power density. Application of PET is in generation of power from renewable energy sources, especially wind and solar. Other important application include grid tied inverters, UPS e.t.c. In this thesis non-resonant, single stage, bi-directional PET is considered. The main objective of this converter is to generate adjustable speed and magnitude pulse width modulated (PWM) ac waveforms from an ac or dc grid with a high frequency ac link. The windings of a high frequency transformer contains leakage inductance. Any switching transition of the power electronic converter connecting the inductive load and the transformer requires commutation of leakage energy. Commutation by passive means results in power loss, decrease in the frequency of operation, distortion in the output voltage waveform, reduction in reliability and power density. In this work a source based partially loss-less commutation of leakage energy has been proposed. This technique also results in partial soft-switching. A series of converters with novel PWM strategies have been proposed to minimize the frequency of leakage inductance commutation. These PETs achieve most of the important features of modern PWM ac drives including 1) Input power factor correction, 2) Common

  16. Spectroscopic AC susceptibility imaging (sASI) of magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ficko, Bradley W., E-mail: Bradley.W.Ficko@Dartmouth.edu; Nadar, Priyanka M.; Diamond, Solomon G.

    2015-02-01

    This study demonstrates a method for alternating current (AC) susceptibility imaging (ASI) of magnetic nanoparticles (mNPs) using low cost instrumentation. The ASI method uses AC magnetic susceptibility measurements to create tomographic images using an array of drive coils, compensation coils and fluxgate magnetometers. Using a spectroscopic approach in conjunction with ASI, a series of tomographic images can be created for each frequency measurement set and is termed sASI. The advantage of sASI is that mNPs can be simultaneously characterized and imaged in a biological medium. System calibration was performed by fitting the in-phase and out-of-phase susceptibility measurements of an mNP sample with a hydrodynamic diameter of 100 nm to a Brownian relaxation model (R{sup 2}=0.96). Samples of mNPs with core diameters of 10 and 40 nm and a sample of 100 nm hydrodynamic diameter were prepared in 0.5 ml tubes. Three mNP samples were arranged in a randomized array and then scanned using sASI with six frequencies between 425 and 925 Hz. The sASI scans showed the location and quantity of the mNP samples (R{sup 2}=0.97). Biological compatibility of the sASI method was demonstrated by scanning mNPs that were injected into a pork sausage. The mNP response in the biological medium was found to correlate with a calibration sample (R{sup 2}=0.97, p<0.001). These results demonstrate the concept of ASI and advantages of sASI. - Highlights: • Development of an AC susceptibility imaging model. • Comparison of AC susceptibility imaging (ASI) and susceptibility magnitude imaging (SMI). • Demonstration of ASI and spectroscopic ASI (sASI) using three different magnetic nanoparticle types. • SASI scan separation of three different magnetic nanoparticles samples using 5 spectroscopic frequencies. • Demonstration of biological feasibility of sASI.

  17. Silicon (BSFR) solar cell AC parameters at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, R Anil; Suresh, M.S. [ISRO Satellite Center, Bangalore- 560 017 (India); Nagaraju, J. [Solar Energy and Thermodynamic Laboratory, Department of Instrumentation, Indian Institute of Science, Bangalore- 560 012 (India)

    2005-01-31

    The AC parameters of back surface field reflected (BSFR) silicon solar cell are measured at different cell temperatures (198-348K) both in forward and reverse bias under dark condition using impedance spectroscopy technique. It is found that cell capacitance increases with temperature whereas cell resistance decreases, in forward bias voltage. Beyond maximum power point voltage, the cell inductance (0.28{mu}H) is measured, as the inductive reactance is comparable with cell series resistance. The measured cell parameters (cell capacitance, dynamic resistance, etc) are used to calculate the mean carrier lifetime and diode factor at different cell temperatures.

  18. GaAs/Ge solar cell AC parameters under illumination

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, R.A.; Suresh, M.S. [ISRO Satellite Center, Bangalore (India); Nagaraju, J. [Indian Institute of Science, Bangalore (India). Department of Instrumentation, Solar Energy Laboratory

    2004-04-01

    The ac parameters of GaAs/Ge solar cell were measured under illumination at different cell temperatures using impedance spectroscopy technique. They are compared with the dark measurements. It is found that the cell capacitance is higher and cell resistance is lower under illumination than in dark for all cell terminal voltages. The cell capacitances at the corresponding maximum power point voltage (terminal) do not vary with temperature where as the cell resistance decreases. The cell capacitance under illumination is estimated from the dark cell capacitance and it is in good agreement with the measured illumination data. (author)

  19. Measurement of Current Profile in a Tokamak Through AC Modulation

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The plasma current is modulated with an alternating current (ac) component in a frequency range of 90 Hz~900 Hz in the plateau discharge phase in the CT-6B tokamak. A plasma electric conductivity profile in a form of (1 - r2/a2)α with a parameter α, which is fitted with the experimental data, can be determined. The effects of magnetic shear in a tokamak field configuration on the current penetration are taken into account in the numerical simulation. The measurement method and obtained results are discussed.

  20. AC Power Local Network with Multiple Power Routers

    Directory of Open Access Journals (Sweden)

    Ryo Takahashi

    2013-12-01

    Full Text Available Controlling power flow and achieving appropriate matching between power sources and loads according to the quality of energy is expected to be one of the approaches to reduce wasted energy consumption. A power router, proposed recently, has the capability of realizing circuit switching in a power distribution network. This study focuses on the feasibility of an AC power routing network system composed of multiple power routers. To evaluate the feasibility, we experimentally confirm the circuit switching operation of the parallel and series configurations of the power routers, so that the network system can be designed by the combination of parallel and series configurations.

  1. Propiedades acústicas de los paneles de carrizo

    Directory of Open Access Journals (Sweden)

    Díaz, César

    2012-03-01

    Full Text Available Reed is a plant species very similar to common cane which is widespread all over the Earth. It is an ecological and sustainable material which is low-cost, aesthetically attractive, easy to obtain and install, and can be used in different construction systems. This work analyses the acoustic properties of reed panels from the point of view of sound absorption and sound insulation against airborne noise, according to the corresponding EN ISO standards. The experimental results obtained point to the conclusion that reed panels are suitable construction systems for controlling reverberant sound within a space, and that the sound reduction index values for different thicknesses of reed panels, or reed panels used in combination with wood particle boards, demonstrate the possibility of using them in construction as an element on the facades and roofs of buildings and for interior partitions.

    El carrizo es una especie vegetal, parecida a la caña común, que se encuentra ampliamente distribuida en la superficie terrestre. Es un material ecológico y sostenible de bajo coste, estéticamente aceptable, fácil de obtener y colocar, que permite generar diferentes sistemas constructivos. En este trabajo se analizan las propiedades acústicas de los paneles de carrizo en lo referente a la absorción acústica y al aislamiento acústico a ruido aéreo, para ello se han aplicado los procedimientos de las normas EN ISO correspondientes. De los resultados experimentales obtenidos se concluye que los paneles de carrizo son unos sistemas constructivos adecuados para el control del sonido reverberante en un recinto y que los valores del índice de reducción acústica de paneles de diferentes espesores o en combinación con tableros de partículas de madera muestran la posibilidad de utilizarlos en la edificación como elemento de fachada, en cubiertas de edificios y particiones interiores.

  2. Technical Aspects of the Advanced Camera For Surveys Repair (ACS-R)

    Science.gov (United States)

    Rinehart, Stephen; Cheng, Edward S.; Sirianni, Marco

    2008-01-01

    The ACS Repair (ACS-R) team includes contributors from NASA's Goddard Space Flight Center, Ball Aerospace, and Teledyne Imaging Sensors; It determined that all of the capabilities of the ACS could be restored and created a concept for the ACS-R component of SN4. ACSR will restore the WFC of ACS by replacing the existing CCD Electronics Box (CEB) with the CEB-Replacement (CEB-R) and providing power from a new Low Voltage Power Supply Replacement (LVPS-8). The new LVPS-R will also attempt to restore the HRC function by providing power through the original power bus. In this presentation, we faeus on the concept and technical aspects of the ACS-R.

  3. Signal Peptide of Potato PinⅡ Enhances the Expression of Cry1Ac in Transgenic Tobacco

    Institute of Scientific and Technical Information of China (English)

    Yun-Jun LIU; Yuan YUAN; Jun ZHENG; Ya-Zhong TAO; Zhi-Gang DONG; Jian-Hua WANG; Guo-Ying WANG

    2004-01-01

    The modified Cry1Ac was expressed in transgenic tobacco plants.To allow secretion of the Cry1Ac protein into the intercellular space,the signal peptide sequence of potato proteinase inhibitor Ⅱ(pinⅡ)was N-terminally fused to the CrylAc encoding region.Expression of Cry1Ac in transgenic tobacco plants was assayed with ELISA.The results showed that pinⅡ signal peptide sequence enhanced the expression of Cry 1 Ac protein and led to the secretion of the Cry 1Ac protein in transgenic tobacco plants.GFP gene was also fused to the signal peptide sequence and transformed to tobacco.The results of fluorescent detection showed that GFP had localized in the apoplast of transgenic plants.

  4. Low-temperature transport in ac-driven quantum dots in the Kondo regime

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Rosa; Aguado, Ramon; Platero, Gloria; Tejedor, Carlos

    2001-08-15

    We present a fully nonequilibrium calculation of the low-temperature transport properties of a quantum dot in the Kondo regime when an ac potential is applied to the gate. We solve a time-dependent Anderson model with finite on-site Coulomb interaction. The interaction self-energy is calculated up to second order in perturbation theory in the on-site interaction, in the context of the Keldysh nonequilibrium technique, and the effect of the ac voltage is taken into account exactly for all ranges of ac frequencies and ac intensities. The obtained linear conductance and time-averaged density of states of the quantum dot evolve in a nontrivial way as a function of the ac frequency and ac intensity of the harmonic modulation.

  5. Spin-exchange collision mixing of the K and Rb ac Stark shifts

    Science.gov (United States)

    Chen, Yao; Quan, Wei; Duan, Lihong; Lu, Yan; Jiang, Liwei; Fang, Jiancheng

    2016-11-01

    In a hybrid pumping alkali-metal vapor cell filled with both K and Rb atoms, the K atom spins are optically pumped by the laser and the Rb atom spins are polarized by the K spins through spin exchange. We discovered that the ac Stark shift of the Rb atom spins, caused by the far-off-resonant pumping laser tuned to the K absorption lines, was mixed together with the ac Stark shift of the K atom spins through fast spin exchange. This mixing is studied and we demonstrate a K-Rb-21Ne comagnetometer in which the ac Stark shift of the Rb atom spins is eliminated by compensating for the Rb ac Stark shift with the K ac Stark shift. An ac Stark shift elimination method has been developed.

  6. System and method for determining stator winding resistance in an AC motor

    Science.gov (United States)

    Lu, Bin; Habetler, Thomas G.; Zhang, Pinjia; Theisen, Peter J.

    2011-05-31

    A system and method for determining stator winding resistance in an AC motor is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of an AC motor. The circuit includes at least one contactor and at least one switch to control current flow and terminal voltages in the AC motor. The system also includes a controller connected to the circuit and configured to modify a switching time of the at least one switch to create a DC component in an output of the system corresponding to an input to the AC motor and determine a stator winding resistance of the AC motor based on the injected DC component of the voltage and current.

  7. Control of hybrid AC/DC microgrid under islanding operational conditions

    DEFF Research Database (Denmark)

    Ding, G.; Gao, F.; Zhang, S.

    2014-01-01

    This paper presents control methods for hybrid AC/DC microgrid under islanding operation condition. The control schemes for AC sub-microgrid and DC sub-microgrid are investigated according to the power sharing requirement and operational reliability. In addition, the key control schemes...... of interlinking converter with DC-link capacitor or energy storage, which will devote to the proper power sharing between AC and DC sub-microgrids to maintain AC and DC side voltage stable, is reviewed. Combining the specific control methods developed for AC and DC sub-microgrids with interlinking converter......, the whole hybrid AC/DC microgrid can manage the power flow transferred between sub-microgrids for improving on the operational quality and efficiency....

  8. Similarly potent inhibition of adenylyl cyclase by P-site inhibitors in hearts from wild type and AC5 knockout mice.

    Directory of Open Access Journals (Sweden)

    Joerg H Braeunig

    Full Text Available Adenylyl cyclase type 5 (AC5 was described as major cardiac AC isoform. The knockout of AC5 (AC5KO exerted cardioprotective effects in heart failure. Our study explored the impact of AC5KO on mouse heart AC activities and evaluated putative AC5-selective inhibitors. In cardiac membranes from AC5KO mice, basal AC activity was decreased, while AC stimulation was intact. The putative AC5-selective P-site inhibitors SQ22,536 [9-(tetra-hydro-2-furanyl-9H-purin-6-amine], vidarabine (9-β-D-arabinosyladenine and NKY80 [2-amino-7-(2-furanyl-7,8-dihydro-5(6H-quinazolinone] inhibited recombinant AC5 more potently than AC2 and AC1, but selectivity was only modest (∼4-40-fold. These compounds inhibited cardiac AC from WT and AC5KO mice with similar potencies. In conclusion, AC regulation in AC5KO hearts was unimpaired, questioning the supposed dominant role of AC5 in the heart. Moreover, the AC inhibitors SQ22,536, NKY80 and vidarabine lack adequate selectivity for AC5 and, therefore, do not present suitable tools to study AC5-specific functions.

  9. Three-phase AC-AC power converters based on matrix converter topology matrix-reactance frequency converters concept

    CERN Document Server

    Szczesniak, Pawel

    2013-01-01

    AC voltage frequency changes is one of the most important functions of solid state power converters. The most desirable features in frequency converters are the ability to generate load voltages with arbitrary amplitude and frequency, sinusoidal currents and voltages waveforms; the possibility of providing unity power factor for any load; and, finally, a simple and compact power circuit. Over the past decades, a number of different frequency converter topologies have appeared in the literature, but only the converters with either a voltage or current DC link are commonly used in industrial app

  10. Security analysis of interconnected AC/DC systems

    DEFF Research Database (Denmark)

    Eriksson, Robert

    2015-01-01

    This paper analyses N-1 security in an interconnected ac/dc transmission system using power transfer distribution factors (PTDFs). In the case of a dc converter outage the power needs to be redistributed among the remaining converter to maintain power balance and operation of the dc grid. The red......This paper analyses N-1 security in an interconnected ac/dc transmission system using power transfer distribution factors (PTDFs). In the case of a dc converter outage the power needs to be redistributed among the remaining converter to maintain power balance and operation of the dc grid...... voltage control design consider the power distribution for a converter outage. By proper design and utilizing the proposed method increases the N-1 security and the secure transfer limits. This article proposes a method which minimizes the 2-norm of the sum of the PTDFs with constraints of not violating...... any line or transformer limits. Simulations were performed in a model of the Nordic power system where a dc grid is placed on top. The simulation supports the method as a tool to consider transfer limits in the grid to avoid violate the same and increase the security after a converter outage....

  11. Aspectos económicos del aislamiento acústico

    Directory of Open Access Journals (Sweden)

    Amarilla, Beatriz C.

    1990-12-01

    Full Text Available The general objective of this study was to analyze the soundproofing/cost ratio with different building alternatives for interior walls and floors. This technical-economic study was divided into three parts: — Dividing walls (environmental noises — Floors (impact noises — Special Solutions (double walls, floating floors, etcetera The results show that in developing countries the most costly solutions are not always the best for housing, as far as soundproofing is concerned. A good knowledge of the economic aspects related to this matter allows obtaining a good quality at a moderate cost, which is a priority in this type of country.

    El objetivo general de este trabajo fue el de analizar el comportamiento de la relación costo-aislamiento acústico en soluciones constructivas alternativas para muros interiores y entrepisos. Este estudio técnico-económico comprende tres partes: * Muros divisorios (ruidos aéreos. * Entrepisos (ruidos de impacto. * Soluciones especiales (muros de doble hoja, pisos flotantes, etc. Se llega a la conclusión que, en los países en desarrollo, no siempre las mejores soluciones para la vivienda, desde el punto de vista acústico, son las de mayor costo. Conocer en profundidad los aspectos económicos de esta cuestión significa poder lograr una buena calidad con costos moderados, lo cual constituye una prioridad en este tipo de países.

  12. AcMNPV As A Model for Baculovirus DNA Replication

    Institute of Scientific and Technical Information of China (English)

    Eric B. Carstens

    2009-01-01

    Baculoviruses were first identified as insect-specific pathogens, and it was this specificity that lead to their use as safe, target specific biological pesticides. For the past 30 years, AcMNPV has served as the subject of intense basic molecular research into the baculovirus infectious cycle including the interaction of the virus with a continuous insect cell line derived from Spodoptera frugiperda. The studies on baculoviruese have led to an in-depth understanding of the physical organization of the viral genomes including many complete genomic sequences, the time course of gene expression, and the application of this basic research to the use of baculoviruses not only as insecticides, but also as a universal eukaryotic protein expression system, and a potential vector in gene therapy. A great deal has also been discovered about the viral genes required for the replication of the baculovirus genome, while much remains to be learned about the mechanism of viral DNA replication. This report outlines the current knowledge of the factors involved in baculovirus DNA replication, using data on AcMNPV as a model for most members of the Baculoviridae.

  13. Memory Convergence and Optimization with Fuzzy PSO and ACS

    Directory of Open Access Journals (Sweden)

    Subhash C. Pandey

    2008-01-01

    Full Text Available Associative neural memories are models of biological phenomena that allow for the storage of pattern associations and the retrieval of the desired output pattern upon presentation of a possibly noisy or incomplete version of an input pattern. In this study, we introduce fuzzy swarm particle optimization technique for convergence of associative neural memories based on fuzzy set theory. A Fuzzy Particle Swarm Optimization (FPSO consists of clustering of swarm's particle by applying fuzzy c-mean algorithm to attain the neighborhood best. We present a singular value decomposition method for the selection of efficient rule from a given rule base required to attain the global best. Finally, we illustrate the proposed method by virtue of some examples. Further, ant colony system ACS algorithm is used to study the Symmetric Traveling Salesman Problem TSP. The optimum parameters for this algorithm have to found by trial and error. The ACS parameters working in a designed subset of TSP instances has also been optimized by virtue of Particle Swarm Optimization PSO.

  14. SQUIDs De-fluxing Using a Decaying AC Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Matlashov, Andrei Nikolaevich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Semenov, Vasili Kirilovich [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Anderson, Bill [Senior Scientific, LLC, Albuquerque, NM (United States)

    2016-06-08

    Flux trapping is the Achilles’ heel of all superconductor electronics. The most direct way to avoid flux trapping is a prevention of superconductor circuits from exposure to magnetic fields. Unfortunately this is not feasible if the circuits must be exposed to a strong DC magnetic field even for a short period of time. For example, such unavoidable exposures take place in superparamagnetic relaxation measurements (SPMR) and ultra-low field magnetic resonance imaging (ULF MRI) using unshielded thin-film SQUID-based gradiometers. Unshielded SQUIDs stop working after being exposed to DC magnetic fields of only a few Gauss in strength. In this paper we present experimental results with de-fluxing of planar thin-film LTS SQUID-based gradiometers using a strong decaying AC magnetic field. We used four commercial G136 gradiometers for SPMR measurements with up to a 10 mT magnetizing field. Strong 12.9 kHz decaying magnetic field pulses reliably return SQUIDs to normal operation 50 ms after zeroing the DC magnetizing field. This new AC de-fluxing method was also successfully tested with seven other different types of LTS SQUID sensors and has been shown to dissipate extremely low energy.

  15. Offline detection of broken rotor bars in AC induction motors

    Science.gov (United States)

    Powers, Craig Stephen

    ABSTRACT. OFFLINE DETECTION OF BROKEN ROTOR BARS IN AC INDUCTION MOTORS. The detection of the broken rotor bar defect in medium- and large-sized AC induction machines is currently one of the most difficult tasks for the motor condition and monitoring industry. If a broken rotor bar defect goes undetected, it can cause a catastrophic failure of an expensive machine. If a broken rotor bar defect is falsely determined, it wastes time and money to physically tear down and inspect the machine only to find an incorrect diagnosis. Previous work in 2009 at Baker/SKF-USA in collaboration with the Korea University has developed a prototype instrument that has been highly successful in correctly detecting the broken rotor bar defect in ACIMs where other methods have failed. Dr. Sang Bin and his students at the Korea University have been using this prototype instrument to help the industry save money in the successful detection of the BRB defect. A review of the current state of motor conditioning and monitoring technology for detecting the broken rotor bar defect in ACIMs shows improved detection of this fault is still relevant. An analysis of previous work in the creation of this prototype instrument leads into the refactoring of the software and hardware into something more deployable, cost effective and commercially viable.

  16. NSTE-ACS und STEMI: Zeitfenster zur Intervention?

    Directory of Open Access Journals (Sweden)

    Alber H

    2010-01-01

    Full Text Available Die neuesten Richtlinien zur Behandlung akuter Koronarsyndrome haben die Bedeutung der perkutanen Koronarintervention weiter gestärkt. Unverändert ist jedoch die Tatsache, dass ein richtig und individuell gewähltes Zeitfenster zur Intervention essenziell für den Benefit der mechanischen Revaskularisation ist. Angesichts vieler möglicher Zeitverzögerungen, vor allem im ländlichen Raum, kann im Einzelfall auch heute noch beim STEMI einer Fibrinolyse, häufig gefolgt von einer invasiven Abklärung innerhalb eines Tages, der Vorzug gegeben werden. Beim NSTE-ACS ist eine frühe Risikostratifizierung wichtig für die zeitliche Planung der Intervention. In allen Fällen bedarf es jedoch einer kontinuierlichen und konstruktiven Interaktion aller im Management von ACS-Patienten/innen beteiligten Berufsgruppen, um diesen sich stetig ändernden Empfehlungen mit dem Ziel der Prognoseverbesserung adäquat Rechnung tragen zu können.

  17. Long-range response in ac electricity grids

    Science.gov (United States)

    Jung, Daniel; Kettemann, Stefan

    2016-07-01

    Local changes in the topology of electricity grids can cause overloads far away from the disturbance [D. Witthaut and M. Timme, Eur. Phys. J. B 86, 377 (2013), 10.1140/epjb/e2013-40469-4], making the prediction of the robustness against changes in the topology—for example, caused by power outages or grid extensions—a challenging task. The impact of single-line additions on the long-range response of dc electricity grids has recently been studied [D. Labavić, R. Suciu, H. Meyer-Ortmanns, and S. Kettemann, Eur. Phys. J.: Spec. Top. 223, 2517 (2014), 10.1140/epjst/e2014-02273-0]. By solving the real part of the static ac load flow equations, we conduct a similar investigation for ac grids. In a regular two-dimensional grid graph with cyclic boundary conditions, we find a power law decay for the change of power flow as a function of distance to the disturbance over a wide range of distances. The power exponent increases and saturates for large system sizes. By applying the same analysis to the German transmission grid topology, we show that also in real-world topologies a long-ranged response can be found.

  18. Input current shaped ac-to-dc converters

    Science.gov (United States)

    1985-01-01

    Input current shaping techniques for ac-to-dc converters were investigated. Input frequencies much higher than normal, up to 20 kHz were emphasized. Several methods of shaping the input current waveform in ac-to-dc converters were reviewed. The simplest method is the LC filter following the rectifier. The next simplest method is the resistor emulation approach in which the inductor size is determined by the converter switching frequency and not by the line input frequency. Other methods require complicated switch drive algorithms to construct the input current waveshape. For a high-frequency line input, on the order of 20 kHz, the simple LC cannot be discarded so peremptorily, since the inductor size can be compared with that for the resistor emulation method. In fact, since a dc regulator will normally be required after the filter anyway, the total component count is almost the same as for the resistor emulation method, in which the filter is effectively incorporated into the regulator.

  19. SOLAR TO AC POWER SOURCE FOR REMOTE AREAS USING SEIG

    Directory of Open Access Journals (Sweden)

    MEHMET AKBABA

    2012-02-01

    Full Text Available Photovoltaic generators (PVG are increasingly used to provide electricity in remote areas. However, in many applications the DC generated electricity by a PVG need to be converted to AC. Traditionally DC to AC inverters have been widely used for this purpose. In this paper, a different system is proposed in which a self excited induction generator (SEIG driven by a permanent magnet DC motor (DCM and powered from a PVG through a maximum power point tracker (MPPT are used. A step-up chopper is utilized as an MPPT unit. The proposed system is modelled in time domain, and a detailed transient and steady-state analysis are presented. The main reason behind analyzing the system in the time domain is because of the fact that for unknown speeds, the methods developed for steady-state analysis of SEIGs can not be applied. The presented work shows that the full available power of the PVG can be harnessed by selecting suitable values for the duty cycle and the frequency of the step up chopper and the excitation capacitor of the SEIG. It is also shown that with such a combination power utilization efficiency of more than 83% can be achieved.

  20. ACS sampling system: design, implementation, and performance evaluation

    Science.gov (United States)

    Di Marcantonio, Paolo; Cirami, Roberto; Chiozzi, Gianluca

    2004-09-01

    By means of ACS (ALMA Common Software) framework we designed and implemented a sampling system which allows sampling of every Characteristic Component Property with a specific, user-defined, sustained frequency limited only by the hardware. Collected data are sent to various clients (one or more Java plotting widgets, a dedicated GUI or a COTS application) using the ACS/CORBA Notification Channel. The data transport is optimized: samples are cached locally and sent in packets with a lower and user-defined frequency to keep network load under control. Simultaneous sampling of the Properties of different Components is also possible. Together with the design and implementation issues we present the performance of the sampling system evaluated on two different platforms: on a VME based system using VxWorks RTOS (currently adopted by ALMA) and on a PC/104+ embedded platform using Red Hat 9 Linux operating system. The PC/104+ solution offers, as an alternative, a low cost PC compatible hardware environment with free and open operating system.

  1. Perfecting the Photometric Calibration of the ACS CCD Cameras

    Science.gov (United States)

    Bohlin, Ralph C.

    2016-09-01

    Newly acquired data and improved data reduction algorithms mandate a fresh look at the absolute flux calibration of the charge-coupled device cameras on the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The goals are to achieve a 1% accuracy and to make this calibration more accessible to the HST guest investigator. Absolute fluxes from the CALSPEC1 database for three primary hot 30,000-60,000K WDs define the sensitivity calibrations for the Wide Field Channel (WFC) and High Resolution Channel (HRC) filters. The external uncertainty for the absolute flux is ˜1%, while the internal consistency of the sensitivities in the broadband ACS filters is ˜0.3% among the three primary WD flux standards. For stars as cool as K type, the agreement with the CALSPEC standards is within 1% at the WFC1-1K subarray position, which achieves the 1% precision goal for the first time. After making a small adjustment to the filter bandpass for F814W, the 1% precision goal is achieved over the full F814W WFC field of view for stars of K type and hotter. New encircled energies and absolute sensitivities replace the seminal results of Sirianni et al. that were published in 2005. After implementing the throughput updates, synthetic predictions of the WFC and HRC count rates for the average of the three primary WD standard stars agree with the observations to 0.1%.

  2. Research on the Plasma Anemometer Based on AC Glow Discharge

    Directory of Open Access Journals (Sweden)

    Bing Yu

    2017-01-01

    Full Text Available A new plasma anemometer based on AC glow discharge is designed in this article. Firstly, theoretical analysis of plasma anemometer working principle is introduced to prove the feasibility of the experimental measurement method. Then the experiments are carried out to study the effects of different parameters on the static discharge characteristics of the plasma anemometer system, by which the system optimization methods are obtained. Finally, several groups of appropriate parameters are selected to build the plasma anemometer system based on resistance capacitance coupling negative feedback AC glow discharge, and different airflow speeds are applied to obtain the achievable velocity measurement range. The results show that there is a linear relationship between airflow velocity and discharge current in an allowable error range, which can be applied for airflow velocity measurement. Negative feedback coupling module, which is composed of the coupling resistance and the coupling capacitance, has good effects on improving the system stability. The measurement range of the airflow velocity is significantly increased when the electrode gap is 3 mm, coupling resistance is 470 Ω, and coupling capacitance is 220 pF.

  3. AC-driven organic light emission devices with carbon nanotubes

    Science.gov (United States)

    Jeon, So-Yeon; Yu, SeGi

    2017-02-01

    We have investigated alternating current (AC)-driven organic light-emitting devices (OLEDs), with carbon nanotubes (CNTs) incorporated within the emission layer. With CNT incorporation, the brightness of the OLEDs was substantially improved, and the turn-on voltage was reduced by at least a factor of five. Furthermore, the current levels of the CNT-incorporated OLEDs were lower than that of the reference device. A roughly 70% decrease in the current level was obtained for a CNT concentration of 0.03 wt%. This was accomplished by keeping the concentration of CNTs low and the length of CNTs short, which helped to suppress the percolation networking of CNTs within the emitting layer. Strong local electric fields near the end-tips of CNTs and micro-capacitors formed by dispersed CNTs might have caused this high brightness and these low currents. CNT incorporation in the emitting layer can improve the characteristics of AC-driven OLEDs, which are considered to be one of the candidates for flat panel displays and lightning devices.

  4. Perfecting the Photometric Calibration of the ACS CCD Cameras

    CERN Document Server

    Bohlin, Ralph C

    2016-01-01

    Newly acquired data and improved data reduction algorithms mandate a fresh look at the absolute flux calibration of the CCD cameras on the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The goals are to achieve a 1\\% accuracy and to make this calibration more accessible to the HST guest investigator. Absolute fluxes from the CALSPEC\\footnote{http://www.stsci.edu/hst/observatory/crds/calspec.html} database for three primary hot 30,000--60,000K WDs define the sensitivity calibrations for the WFC and HRC filters. The external uncertainty for the absolute flux is $\\sim$1\\%, while the internal consistency of the sensitivities in the broadband ACS filters is $\\sim$0.3\\% among the three primary WD flux standards. For stars as cool as K type, the agreement with the CALSPEC standards is within 1\\% at the WFC1-1K subarray position, which achieves the 1\\% precision goal for the first time. After making a small adjustment to the filter bandpass for F814W, the 1\\% precision goal is achieved over the full ...

  5. New Sky Flats for HST's ACS/WFC

    Science.gov (United States)

    Lucas, Ray A.; Grogin, Norman A.

    2016-06-01

    We have begun experiments to make new sky flat files for HST's ACS/WFC. Sky flats can be especially useful for deep imaging in such as programs as deep, extragalactic survey programs because they can help to better deal with noise at low levels. Although we also hope to make similar sky flats for some other popular filters including F606W and F814W, we are beginning this experiment with the F435W filter on the ACS/WFC since it is a popular filter in use in many deep extragalactic surveys, and since the bluer filters such as F435W generally have lower throughput and images in that filter are typically noisier than others at some longer mid-optical wavelengths. Initially, although sources will be masked in these images, etc. we are endeavoring to use just post-SM4 F435W images of duration equal to or greater than 800 seconds and which are free of bright stars in order to try and avoid scattered light and sky background color issues as much as possible, although the sky in different images taken at different times and in different directions will likely have some different background levels and color terms in any event. However, our hope is that the final sky flats will be of sufficient S/N to be good calibrators for deep survey programs.

  6. [Antiadhesive potencial of Rhodococcus erythropolis IMB Ac-5017 biosurfactants].

    Science.gov (United States)

    Pirog, T P; Gritsenko, N A; Konon, A D; Shevchuk, T A; Iutinskaia, G A

    2014-01-01

    The effect of Rhodococcus erythropolis IMB Ac-5017 biosurfactants (surface-active substances, SAS) with different degree of purification on attachment of bacteria (Escherichia coli IEM-1, Bacillus subtilis BT-2, Proteus vulgaris BT-1, Staphylococcus aureus BMC-1, Pseudomonas aeruginosa P-55, Enterobacter cloacae AC-22, Erwinia aroidaeae B-433), yeasts (Candida albicans D-6) and fungi (Aspergillus niger P-3, Fusarium culmorum T-7) to the abiotic surfaces (glass, plastic, ceramics, steel, linoleum) was studied. The dependence of microorganisms adhesion on degree of SAS purification (supernatant, purified SAS solution), SAS concentration (0,04-1,25 mg/ml), type of surface and test-cultures was established. The adhesion of majority investigated bacterial cells after treatment of abiotic surfaces with supernatant of cultural liquid with SAS concentration 0,06-0,25 mg/ml was on the average 20-45, yeasts C. albicans D-6--30-75% and was less than that purified SAS solution with the same concentration. Higher antiadhesive activity of supernatant as compared to purified SAS solution testifies to possibility of exception of the expensive stage of isolation and purification at obtaining of preparations with antiadhesive properties.

  7. AC2 and AC4 proteins of Tomato yellow leaf curl China virus and Tobacco curly shoot virus mediate suppression of RNA silencing

    Institute of Scientific and Technical Information of China (English)

    CUI Xiaofeng; ZHOU Xueping

    2004-01-01

    Tomato yellow leaf curl China virus Y10 isolate (TYLCCNV-Y10) alone could systemically infect host plants such as Nicotiana benthamiana without symptoms. In contrast, Tobacco curly shoot virus Y35 isolate (TbCSV-Y35) alone induces leaf curl symptoms in N. benthamiana. When inoculated into transgenic N. benthamiana plants expressing GFP gene (line 16c), TYLCCNV-Y10 neither reverses the established GFP silencing nor blocks the onset of GFP silencing. In contrast, TbCSV-Y35 can partially reverse the established GFP silencing and block the onset of GFP silencing in new leaves. In the patch co-infiltration assays, the AC2 and AC4 proteins of TYLCCNV-Y10 and TbCSV-Y35 could suppress local GFP silencing and delay systemic GFP silencing, suggesting that they are suppressors of RNA silencing. Comparison of the accumulation levels of GFP mRNA in the co-infiltration patches showed that Y10 AC2 and Y35 AC2 proteins had similar efficiency for suppression of RNA silencing. However, Y35 AC4 protein functioned as a stronger suppressor of RNA silencing than Y10 AC4 protein. Therefore, the pathogenicity difference between TbCSV-Y35 and TYLCCNV-Y10 may be related to the functional difference in their AC4 proteins.

  8. 直接AC/AC变换器输出电压及电流纹波分析%Analysis of Output Voltage and Current Ripple for Direct AC/AC Converter

    Institute of Scientific and Technical Information of China (English)

    文锋; 赵冉; 刘菁

    2009-01-01

    为解决直接AC/AC交换器的输出纹波计算问题,本文建立了以DC/DC变换器结构为基础的六种AC/AC变换器的理想模型.利用这些理想模型,DC/DC变换器的一般分析方法可方便地引入到AC/AC变换器的分析中,然后,论文以Buck型AC/AC变换器为例,给出其电路输出纹波系数的计算公式.为了证明理论分析的正确性,搭建了实验电路,实验结果与理论计算得到了很好的吻合.

  9. Update History of This Database - AcEST | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available [ Credits ] BLAST Search Image Search Home About Archive Update History Contact us AcEST Up...date History of This Database Date Update contents 2013/01/10 Errors found on AcEST Conting data hav...iew/acest/ ) is released. Joomla SEF URLs by Artio About This Database Database Description Download License Up...date History of This Database Site Policy | Contact Us Update History of This Database - AcEST | LSDB Archive ...

  10. 21 CFR 880.5510 - Non-AC-powered patient lift.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Non-AC-powered patient lift. 880.5510 Section 880... Devices § 880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a... patient in the horizontal or other required position from one place to another, as from a bed to a...

  11. Symposium on Energy Storage Materials Energy and Fuel Division, 246th ACS National Meeting

    Science.gov (United States)

    2015-04-17

    Approved for Public Release; Distribution Unlimited Final Report: Symposium on Energy Storage Materials Energy and Fuel Division, 246th ACS National...Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 ARO, symposium, batteries, energy, ACS REPORT DOCUMENTATION PAGE 11. SPONSOR...journals: Final Report: Symposium on Energy Storage Materials Energy and Fuel Division, 246th ACS National Meeting Report Title The symposium took place on

  12. Developing Test Apparatus and Measurements of AC Loss of High Temperature Superconductors

    Science.gov (United States)

    2012-11-01

    superconducting wires can be very effectively reduced in proportion of the number of filaments. The oxygen annealing eliminates the residual coupling losses by...made out of YBCO superconducting wires were studied, confirming the simulation method used to calculate and predict AC loss and hysteretic effects of... oxygen annealing were tested in order to determine their effect on AC loss reduction. Results showed that the AC loss in multifilament

  13. Using a nonparametric PV model to forecast AC power output of PV plants

    OpenAIRE

    Almeida, Marcelo Pinho; Perpiñan Lamigueiro, Oscar; Narvarte Fernández, Luis

    2015-01-01

    In this paper, a methodology using a nonparametric model is used to forecast AC power output of PV plants using as inputs several forecasts of meteorological variables from a Numerical Weather Prediction (NWP) model and actual AC power measurements of PV plants. The methodology was built upon the R environment and uses Quantile Regression Forests as machine learning tool to forecast the AC power with a confidence interval. Real data from five PV plants was used to validate the methodology, an...

  14. Correlation of AC Loss Data from Magnetic Susceptibility Measurements with YBCO Film Quality (Postprint)

    Science.gov (United States)

    2012-02-01

    AFRL-RZ-WP-TP-2012-0100 CORRELATION OF AC LOSS DATA FROM MAGNETIC SUSCEPTIBILITY MEASUREMENTS WITH YBCO FILM QUALITY (POSTPRINT) Paul N...CORRELATION OF AC LOSS DATA FROM MAGNETIC SUSCEPTIBILITY MEASUREMENTS WITH YBCO FILM QUALITY (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT...spreading of the temperature-dependent ac susceptibility curves with increasing applied magnetic field, the quality of the YBCO film generally

  15. Control of hybrid AC/DC microgrid under islanding operational conditions

    DEFF Research Database (Denmark)

    Ding, G.; Gao, F.; Zhang, S.

    2014-01-01

    This paper presents control methods for hybrid AC/DC microgrid under islanding operation condition. The control schemes for AC sub-microgrid and DC sub-microgrid are investigated according to the power sharing requirement and operational reliability. In addition, the key control schemes......, the whole hybrid AC/DC microgrid can manage the power flow transferred between sub-microgrids for improving on the operational quality and efficiency....

  16. Equal pulse width chopping control based on plugged pulse principle in three-phase AC/AC system%基于脉冲阻塞原理的三相AC/AC系统等脉宽斩波控制

    Institute of Scientific and Technical Information of China (English)

    郑诗程; 陈玲; 曹小虎

    2011-01-01

    A circuit topology of three-phase AC/AC system is presented,which needs only six power devices to realize the three-phase AC/AC frequency conversion. The traditional phase-shifted control strategy is replaced by the equal pulse width chopping control strategy based on plugged pulse principle to regulate the amplitude and frequency of output voltage separately or simultaneously. The equal pulse width chopping control strategy is analyzed in detail and the mathematic expression of duty cycle is deduced based on the area equivalent rule according to different frequency and amplitude of anticipant output voltage. Under the environment of PSPICE,the three-phase AC/AC system with the equal pulse width chopping control strategy is simulated. Its main circuit and FPGA-based control circuit are designed and tested. The experimental results are consistent with the simulative results,completely same as the theoretical analysis,which verifies the correctness and feasibility of the introduced control strategy.%针对传统的三相AC/AC变频电路特点,提出了一种新的电路拓扑,仅用6个功率器件即可实现三相AC/AC变频功能.提出基于脉冲阻塞原理的等脉宽斩波控制策略,取代传统的移相控制策略施加于该电路拓扑,实现了三相输出电压幅值、频率分别可调或同时可调.对等脉宽斩波控制策略进行了详细的理论分析.根据期望输出电压的不同频率和幅值.利用面积等效原则,推导出相应占空比的数学表达式.在PSPICE环境下根据脉冲阻塞原理.对三相AC/AC系统进行等脉宽斩波控制仿真.并设计了三相AC/AC系统主电路和基于FPGA的控制电路,完成了相关实验.仿真和实验结果一致,与文中的理论分析结果也完全一致,验证了该AC/AC变频控制策略的正确性及可行性.

  17. An H2A Histone Isotype, H2ac, Associates with Telomere and Maintains Telomere Integrity.

    Directory of Open Access Journals (Sweden)

    Chia-Hsin Su

    Full Text Available Telomeres are capped at the ends of eukaryotic chromosomes and are composed of TTAGGG repeats bound to the shelterin complex. Here we report that a replication-dependent histone H2A isotype, H2ac, was associated with telomeres in human cells and co-immunoprecipitates with telomere repeat factor 2 (TRF2 and protection of telomeres protein 1 (POT1, whereas other histone H2A isotypes and mutations of H2ac did not bind to telomeres or these two proteins. The amino terminal basic domain of TRF2 was necessary for the association with H2ac and for the recruitment of H2ac to telomeres. Depletion of H2ac led to loss of telomeric repeat sequences, the appearance of dysfunctional telomeres, and chromosomal instability, including chromosomal breaks and anaphase bridges, as well as accumulation of telomere-associated DNA damage factors in H2ac depleted cells. Additionally, knockdown of H2ac elicits an ATM-dependent DNA damage response at telomeres and depletion of XPF protects telomeres against H2ac-deficiency-induced G-strand overhangs loss and DNA damage response, and prevents chromosomal instability. These findings suggest that the H2A isotype, H2ac, plays an essential role in maintaining telomere functional integrity.

  18. DC Vs AC - War Of Currents For Future Power Systems A HVDC Technology Overview

    Directory of Open Access Journals (Sweden)

    Anil K. Rai

    2015-08-01

    Full Text Available DC vs AC discussion began in 1880s with development of first commercial power transmission in Wall Street New York. Later when AC technology came into notice by efforts of inventor and researcher Sir Nicola Tesla soon the advantages of AC transmission and AC devices overtook the DC technology. It was hoped that DC technology had lost battle of currents. Today with researches going on FACTS devices and bulk power transmission HVDC has again gained a reputation in power sector. Solution of this centuries old debate is to develop HVDC systems that assists HVAC systems for better performance stability and control

  19. New resistance mechanism in Helicoverpa armigera threatens transgenic crops expressing Bacillus thuringiensis Cry1Ac toxin.

    Science.gov (United States)

    Gunning, Robin V; Dang, Ho T; Kemp, Fred C; Nicholson, Ian C; Moores, Graham D

    2005-05-01

    In Australia, the cotton bollworm, Helicoverpa armigera, has a long history of resistance to conventional insecticides. Transgenic cotton (expressing the Bacillus thuringiensis toxin Cry1Ac) has been grown for H. armigera control since 1996. It is demonstrated here that a population of Australian H. armigera has developed resistance to Cry1Ac toxin (275-fold). Some 70% of resistant H. armigera larvae were able to survive on Cry1Ac transgenic cotton (Ingard) The resistance phenotype is inherited as an autosomal semidominant trait. Resistance was associated with elevated esterase levels, which cosegregated with resistance. In vitro studies employing surface plasmon resonance technology and other biochemical techniques demonstrated that resistant strain esterase could bind to Cry1Ac protoxin and activated toxin. In vivo studies showed that Cry1Ac-resistant larvae fed Cy1Ac transgenic cotton or Cry1Ac-treated artificial diet had lower esterase activity than non-Cry1Ac-fed larvae. A resistance mechanism in which esterase sequesters Cry1Ac is proposed.

  20. Appeals to AC as a Percentage of Appealable Hearing Level Dispositions

    Data.gov (United States)

    Social Security Administration — Longitudinal report detailing the numbers and percentages of Requests for Review (RR) of hearing level decisions or dismissals filed with the Appeals Council (AC)...

  1. Space charge and charge trapping characteristics of cross-linked polyethylene subjected to ac electric stresses

    Science.gov (United States)

    Chong, Y. L.; Chen, G.; Miyake, H.; Matsui, K.; Tanaka, Y.; Takada, T.

    2006-04-01

    This paper reports on the result of space charge evolution in cross-linked polyethylene (XLPE) planar samples approximately 220 µm thick. The space charge measurement technique used in this study is the pulsed electroacoustic method. There are two phases to this experiment. In the first phase, the samples were subjected to dc 30 kVdc mm-1 and ac (sinusoidal) electric stress levels of 30 kVpk mm-1 at frequencies of 1, 10 and 50 Hz ac. In addition, ac space charge under 30 kVrms mm-1 and 60 kVpk mm-1 electric stress at 50 Hz was also investigated. The volts-off results showed that the amount of charge trapped in XLPE sample under dc electric stress is significantly bigger than samples under ac stress even when the applied ac stresses are substantially higher. The second phase of the experiment involves studying the dc space charge evolution in samples that were tested under ac stress during the first phase of the experiment. Ac ageing causes positive charge to become more dominant over negative charge. It was also discovered that ac ageing creates deeper traps, particularly for negative charge. This paper also gives a brief overview of the data processing methods used to analyse space charge under ac electric stress.

  2. Effect of AC electric fields on the stabilization of premixed bunsen flames

    KAUST Repository

    Kim, Minkuk

    2011-01-01

    The stabilization characteristics of laminar premixed bunsen flames have been investigated experimentally for stoichiometric methane-air mixture by applying AC voltage to the nozzle with the single-electrode configuration. The detachment velocity either at blowoff or partial-detachment has been measured by varying the applied voltage and frequency of AC. The result showed that the detachment velocity increased with the applied AC electric fields, such that the flame could be nozzle-attached even over five times of the blowoff velocity without having electric fields. There existed four distinct regimes depending on applied AC voltage and frequency. In the low voltage regime, the threshold condition of AC electric fields was identified, below which the effect of electric fields on the detachment velocity is minimal. In the moderate voltage regime, the flame base oscillated with the frequency synchronized to AC frequency and the detachment velocity increased linearly with the applied AC voltage and nonlinearly with the frequency. In the high voltage regime, two different sub-regimes depending on AC frequency were observed. For relatively low frequency, the flame base oscillated with the applied AC frequency together with the half frequency and the variation of the detachment velocity was insensitive to the applied voltage. For relatively high frequency, the stabilization of the flame was significantly affected by the generation of streamers and the detachment velocity decreased with the applied voltage. © 2010 Published by Elsevier Inc. on behalf of The Combustion Institute. All rights reserved.

  3. Instantaneous characteristics simulation and analysis on three-level brushless AC synchronous generators of aeronautic constant speed and frequency AC power system

    Science.gov (United States)

    Ma, Xiaohe; Shen, Songhua

    2006-11-01

    This paper mainly introduces theoretical analysis and experimental results of instantaneous characteristics on a certain three level brushless three-phase AC synchronous generators. The analysis, modeling and simulations with Simplorer software of Ansoft Company are carried out. It establishes three level generator models, gives theoretical relation matrix equation, and simulates some instantaneous characteristics. Design of the system requires reliable simulation tools with comprehensive component libraries capable of dealing with complex system behavior. The simulation results verify that the proposed system model can efficiently simulate the instantaneous characteristics of the real AC generator system. It gives better design experiences and digital methods for aeronautic constant speed and frequency AC power system.

  4. Design of IRIG-B(AC) code decoder Based on CPLD%基于CPLD的IRIG-B(AC)时间码解调器研制

    Institute of Scientific and Technical Information of China (English)

    王留全; 霍建华

    2013-01-01

    介绍了一种基于CPLD的IRIG-B(AC)码解调电路设计.该IRIG-B(AC)码解调电路具有实时秒脉冲和时、分、秒时间信息并行输出等功能.具有硬件电路和软件编程简单,AC码解调精度高,灵活度和稳定性高,可以方便的进行电路移植,是一种成功的IRIG-B(AC)时间码解调方案.

  5. Six switches solution for single-phase AC/DC/AC converter with capability of second-order power mitigation in DC-link capacitor

    DEFF Research Database (Denmark)

    Liu, Xiong; Wang, Peng; Loh, Poh Chiang

    2011-01-01

    This paper proposes an approach for DC-link second-order harmonic power cancellation in single-phase AC/DC/AC converter with reduced number of switches. The proposed six-switch converter has two bridges with three switches in each of them, where the middle switch in each bridge is shared by the AC...... on their modulation indices of the six-switch converter, and high modulation indices are proved to be feasible for second-order power cancellation in the DC-link based on the phase difference analysis. Both reduced switch numbers and DC electrolytic capacitor size can be achieved using the proposed converter...

  6. RNA interference suppression of mucin 5AC (MUC5AC reduces the adhesive and invasive capacity of human pancreatic cancer cells

    Directory of Open Access Journals (Sweden)

    Yamada Nobuya

    2010-05-01

    Full Text Available Abstract Background MUC5AC is a secretory mucin normally expressed in the surface muconous cells of stomach and bronchial tract. It has been known that MUC5AC de novo expression occurred in the invasive ductal carcinoma and pancreatic intraepithelial neoplasm with no detectable expression in normal pancreas, however, its function remains uncertain. Here, we report the impact of MUC5AC on the adhesive and invasive ability of pancreatic cancer cells. Methods We used two MUC5AC expressing cell lines derived from human pancreatic cancer, SW1990 and BxPC3. Small-interfering (si RNA directed against MUC5AC were used to assess the effects of MUC5AC on invasion and adhesion of pancreas cancer cells in vitro and in vivo. We compared parental cells (SW1990 and BxPC3 with MUC5AC suppressed cells by si RNA (si-SW1990 and si-BxPC3. Results MUC5AC was found to express in more than 80% of pancreatic ductal carcinoma specimens. Next we observed that both of si-SW1990 and si-BxPC3 showed significantly lower adhesion and invasion to extracellular matrix components compared with parental cell lines. Expression of genes associated with adhesion and invasion including several integerins, matrix metalloproteinase (MMP -3 and vascular endothelial growth factor (VEGF were down-regulated in both MUC5AC suppressed cells. Furthermore, production of VEGF and phosphorylation of VEGFR-1 were significantly reduced by MUC5AC down regulation. Both of si-SW1990 and si-BxPC3 attenuated activation of Erk1/2. In vivo, si-SW1990 did not establish subcutaneous tumor in nude mice. Conclusions Knockdown of MUC5AC reduced the ability of pancreatic cancer cells to adhesion and invasion, suggesting that MUC5AC might contribute to the invasive motility of pancreatic cancer cells by enhancing the expression of integrins, MMP-3, VEGF and activating Erk pathway.

  7. A Digital Method for AC/AC Converter Controller by Natural-commutation%自然换流AC/AC变频控制器数字化实现方法

    Institute of Scientific and Technical Information of China (English)

    李光叶; 苏玉民; 文小青

    2011-01-01

    For the dead band in AC/AC converter controller,a design method of both software and hardware is presented. All the trigger pulses are created by DSP.The full digitalization of the system is completed.The self-commutation of the controller is achieved by intelligent utilization of two timers of DSP.The dead band of commutation is greatly reduced.The quality of output waveform is improved observably .The experimental result verify the outstanding effectiveness and precision of the controller.%针对AC/AC变频电路存在的换流死区问题,提出了一种AC/AC变频控制器软、硬件设计方法.该方法中6路触发脉冲均由DSP生成,完成对系统的全数字化控制.通过DSP中两个定时器的合理使用,实现了AC/AC变频器的自然换流,减小了换流死区对输出波形的影响.实验结果表明,所设计的AC/AC变频数字控制系统具有较高的控制精度和较好的控制效果.

  8. Age-related changes in lamin A/C expression in cardiomyocytes.

    Science.gov (United States)

    Afilalo, Jonathan; Sebag, Igal A; Chalifour, Lorraine E; Rivas, Daniel; Akter, Rahima; Sharma, Kamal; Duque, Gustavo

    2007-09-01

    Lamin A and C (A/C) are type V intermediate filaments that form the nuclear lamina. Lamin A/C mutations lead to reduced expression of lamin A/C and diverse phenotypes such as familial cardiomyopathies and accelerated aging syndromes. Normal aging is associated with reduced expression of lamin A/C in osteoblasts and dermal fibroblasts but has never been assessed in cardiomyocytes. Our objective was to compare the expression of lamin A/C in cardiomyocytes of old (24 mo) versus young (4 mo) C57Bl/6J mice using a well-validated mouse model of aging. Lamin B1 was used as a control. Immunohistochemical and immunofluorescence analyses showed reduced expression of lamin A/C in cardiomyocyte nuclei of old mice (proportion of nuclei expressing lamin A/C, 9% vs. 62%, P < 0.001). Lamin A/C distribution was scattered peripherally and perinuclear in old mice, whereas it was homogeneous throughout the nuclei in young mice. Western blot analyses confirmed reduced expression of lamin A/C in nuclear extracts of old mice (ratio of lamin A/C to B1, 0.6 vs. 1.2, P < 0.01). Echocardiographic studies showed increased left ventricular wall thickness with preserved cavity size (concentric remodeling), increased left ventricular mass, and a slight reduction in fractional shortening in old mice. This is the first study to show that normal aging is associated with reduced expression and altered distribution of lamin A/C in nuclei of cardiomyocytes.

  9. AC impedance study of degradation of porous nickel battery electrodes

    Science.gov (United States)

    Lenhart, Stephen J.; Macdonald, D. D.; Pound, B. G.

    1987-01-01

    AC impedance spectra of porous nickel battery electrodes were recorded periodically during charge/discharge cycling in concentrated KOH solution at various temperatures. A transmission line model (TLM) was adopted to represent the impedance of the porous electrodes, and various model parameters were adjusted in a curve fitting routine to reproduce the experimental impedances. Degradation processes were deduced from changes in model parameters with electrode cycling time. In developing the TLM, impedance spectra of planar (nonporous) electrodes were used to represent the pore wall and backing plate interfacial impedances. These data were measured over a range of potentials and temperatures, and an equivalent circuit model was adopted to represent the planar electrode data. Cyclic voltammetry was used to study the characteristics of the oxygen evolution reaction on planar nickel electrodes during charging, since oxygen evolution can affect battery electrode charging efficiency and ultimately electrode cycle life if the overpotential for oxygen evolution is sufficiently low.

  10. Team-oriented Adaptive Droop Control for Autonomous AC Microgrids

    DEFF Research Database (Denmark)

    Shafiee, Qobad; Nasirian, Vahidreza; Guerrero, Josep M.;

    2014-01-01

    This paper proposes a distributed control strategy for voltage and reactive power regulation in ac Microgrids. First, the control module introduces a voltage regulator that maintains the average voltage of the system on the rated value, keeping all bus voltages within an acceptable range. Dynamic...... consensus protocol is used to estimate the average voltage across the Microgrid. This estimation is further utilized by the voltage regulator to elevate/lower the voltage-reactive power (Q-E) droop characteristic, compensating the drop caused by the droop mechanism. The second module, the reactive power...... regulator, dynamically fine-tunes the Q-E coefficients to handle the proportional reactive power sharing. Accordingly, locally supplied reactive power of any source is compared with neighbor sources and the local droop coefficient is adjusted to mitigate and, ultimately, eliminate the load mismatch...

  11. High Voltage AC underground cable systems for power transmission

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Silva, Filipe Miguel Faria da

    2016-01-01

    This paper is a first of two presenting a review of research results in underground cable transmission obtained by the Department of Energy Technology, Aalborg University ET/AAU and Danish TSO Energinet.dk within the last 6 years. The main core of the results are obtained by PhD students research......This paper is a first of two presenting a review of research results in underground cable transmission obtained by the Department of Energy Technology, Aalborg University ET/AAU and Danish TSO Energinet.dk within the last 6 years. The main core of the results are obtained by PhD students...... researching electrical engineering topics related to using underground cables for power transmission at EHV level and including the 420 kV level. The research topics were laid down by ET/AAU and Energinet.dk in the DANPAC (DANish Power systems with AC Cables) research project. The main topics are discussed...

  12. Resistojet control and power for high frequency ac buses

    Science.gov (United States)

    Gruber, Robert P.

    1987-01-01

    Resistojets are operational on many geosynchronous communication satellites which all use dc power buses. Multipropellant resistojets were selected for the Initial Operating Capability (IOC) Space Station which will supply 208 V, 20 kHz power. This paper discusses resistojet heater temperature controllers and passive power regulation methods for ac power systems. A simple passive power regulation method suitable for use with regulated sinusoidal or square wave power was designed and tested using the Space Station multipropellant resistojet. The breadboard delivered 20 kHz power to the resistojet heater. Cold start surge current limiting, a power efficiency of 95 percent, and power regulation of better than 2 percent were demonstrated with a two component, 500 W breadboard power controller having a mass of 0.6 kg.

  13. Using ac dipoles to localize sources of beam coupling impedance

    Directory of Open Access Journals (Sweden)

    N. Biancacci

    2016-05-01

    Full Text Available The beam coupling impedance is one of the main sources of beam instabilities and emittance blow up in circular accelerators. A refined machine impedance evaluation is therefore required in order to understand and model intensity dependent effects and instabilities that may limit the machine performance. For this reason, many impedance source localization techniques have been developed. In this work we present the impedance localization technique based on the observation of phase advance versus intensity at the beam position monitors using ac dipoles to force betatron oscillations. We present analytical formulas for the interpretation of measurements together with simulations to benchmark and illustrate the equations. Studies on the method accuracy for different Fourier transform algorithms are presented as well as first exploratory measurements performed in the LHC.

  14. ACS/SBC Internal Lamp P-flat Monitoring

    Science.gov (United States)

    Avila, Roberto J.; Chiaberge, Marco; Bohlin, Ralph

    2016-06-01

    We report on a Cycle 23 calibration program to monitor the status of the SBC P-flat. We find random pixel to pixel changes to be small, with only ˜2% of pixels having changed by more than 3σ. There are coherent changes that we measure to be above the poisson errors, in some regions as high as 4% peak to peak. We therefore recommend that the ACS team obtain new observations in order to create a new P-flat. We also measured the degradation of the deuterium lamp used to create internal flats. The brightness of the lamp is currently ˜65% of its initial level, the degradation being dependent on lifetime usage.

  15. Input-current shaped ac to dc converters

    Science.gov (United States)

    1986-01-01

    The problem of achieving near unity power factor while supplying power to a dc load from a single phase ac source of power is examined. Power processors for this application must perform three functions: input current shaping, energy storage, and output voltage regulation. The methods available for performing each of these three functions are reviewed. Input current shaping methods are either active or passive, with the active methods divided into buck-like and boost-like techniques. In addition to large reactances, energy storage methods include resonant filters, active filters, and active storage schemes. Fast voltage regulation can be achieved by post regulation or by supplementing the current shaping topology with an extra switch. Some indications of which methods are best suited for particular applications concludes the discussion.

  16. Coherent Spin Polarization in an AC-Driven Mesoscopic Device

    Directory of Open Access Journals (Sweden)

    Asham M. D.

    2012-01-01

    Full Text Available The spin transport characteristics through a mesoscopic device are investigated under the effect of an AC-field. This device consists of two-diluted magnetic semiconductor (DMS leads and a nonmagnetic semiconducting quantum dot. The conductance for both spin parallel and antiparallel alignment in the two DMS leads is deduced. The corresponding equations for giant magnetoresistance (GMR and spin polarization (SP are also deduced. Calculations show an oscillatory behavior of the present studied pa- rameters. These oscillations are due to the coupling of photon energy and spin-up & spin-down subbands and also due to Fano-resonance. This research work is very im- portant for spintronic devices.

  17. ACS photometry of the globular cluster B514

    CERN Document Server

    Galleti, S; Bellazzini, M; Buzzoni, A; Pecci, F F

    2006-01-01

    We present deep F606W, F814W ACS photometry of the recently discovered globular cluster B514, the outermost known globular in the M31 galaxy. The cluster appears quite extended and member stars are unequivocally identified out to ~200 pc from the center. The Color Magnitude Diagram reveals a steep Red Giant Branch (RGB), and a Horizontal Branch (HB) extending blue ward of the instability strip, indicating that B514 is a classical old metal-poor globular cluster. The RGB locus and the position of the RGB Bump are both consistent with a metallicity [Fe/H] ~ -1.8, in excellent agreement with spectroscopic estimates. A preliminary estimate of the integrated absolute V magnitude (M_V< -9.1) suggests that B514 is among the brightest globulars of M31.

  18. The AC magnetic susceptibility of high temperature superconductors

    CERN Document Server

    Salim, M

    2001-01-01

    This research concerns the development of AC magnetic susceptometers and use of susceptometers in analysing high temperature superconductors. Two of the designs were a differential magnetic susceptometer (DMS) and a double coil screening susceptometer (DCSS) whose descriptions are given in detail including coil design, field measurements, susceptometer operation, experimental instrumentation, phase adjustment, susceptometer calibration and sensitivity for each design. Theoretical details are given regarding each design in order to calculate the complex external and internal susceptibility. Investigation concerning the demagnetisation factor of different geometries, and the significant features and limitation for each design are also provided. The susceptometers were applied to a wide range of YBCO samples, which includes bulk samples with different geometry (i.e. Slabs, disk, powder and thick film) and thin films with different oxygen contents. Several silver sheathed Bi-2223 tapes were also involved. This al...

  19. Generic Electronic Board Design to Control 3-Phase Ac

    Directory of Open Access Journals (Sweden)

    RojasMolina A.

    2012-01-01

    Full Text Available This work presents the design and development of a low-cost power manager with controller for a 3-phase AC induction motor, with a wide range of industrial applications. The prototype drive design and development was made using the generic standard on printed board design IPC2221. Power manager consists of two stages. First is control stage, which includes an induction motor control-specific micro-controller. Second is power stage, with IGBTs as switching elements. This design is part of a wider project whose main objective is to advance a methodology to assist the quality improvement of academia-developed electronic prototypes. It is expected that these prototypes will be aligned with industrial standards, facilitating the industry-university connection regarding technological collaboration in the automation and control domain.

  20. Spinning Janus doublets driven in uniform AC electric fields

    CERN Document Server

    Boymelgreen, Alicia; Park, Sinwook; Miloh, Touvia

    2013-01-01

    We provide an experimental proof-of-concept for a robust, continuously rotating microstructure - consisting of two metallodielectric (gold-polystyrene)Janus particles rigidly attached to each other - which is driven in uniform ac fields by asymmetric induced-charge electroosmosis. The pairs (doublets) are stabilized on the substrate surface which is parallel to the plane of view and normal to the direction of the applied electric field. We find that the radius of orbit and angular velocity of the pair are predominantly dependent on the relative orientations of the interfaces between the metallic and dielectric hemispheres and that the electrohydrodynamic particle-particle interactions are small. Additionally, we verify that both the angular and linear velocities of the pair are proportional to the square of the applied field which is consistent with the theory for non-linear electrokinetics. A simple kinematic rigid body model is used to predict the paths and double velocities (angular and linear) based on th...

  1. Measurement of AC losses in different former materials

    DEFF Research Database (Denmark)

    Olsen, Søren Krüger; Træholt, Chresten; Kühle, Anders Van Der Aa

    1998-01-01

    A high temperature superconducting cable may be based on a centrally located cylindrical support, a so-called former. If electrically conductive, the former can contribute to the AC losses through eddy current losses caused by unbalanced axial and tangential magnetic fields. With these measurements...... we aim at investigating the eddy current losses of commonly used former materials. A one layer cable conductor was wound on a glass fibre reinforced polymer (GRFP) former. By inserting a variety of materials into this, it was possible to measure the eddy current losses of each of the former...... candidates separately; for example copper tubes, stainless steel braid, copper braid, corrugated stainless steel tubes, etc. The measured data are compared with the predictions of a theoretical model. Our results show that in most cases, the losses induced by eddy currents in the former are negligible...

  2. Delocalization of disturbances and the stability of ac electricity grids

    Science.gov (United States)

    Kettemann, Stefan

    2016-12-01

    In order to study how local disturbances affect the ac grid stability, we start from nonlinear power balance equations and map them to complex linear wave equations. Having obtained stationary solutions with phases φi at generator and consumer nodes i , we next study the dynamics of deviations. Starting with an initially localized perturbation, it is found to spread in a periodic grid diffusively throughout the grid. We find the parametric dependence of diffusion constant D . We apply the same solution strategy to general grid topologies and analyze their stability against local perturbations. The perturbation remains either localized or becomes delocalized, depending on grid topology, power capacity, and distribution of consumers and generator power Pi. Delocalization is found to increase the lifetime of perturbations and thereby their influence on grid stability, whereas localization results in an exponentially fast decay of perturbations at all grid sites. These results may therefore lead to new strategies to control the stability of electricity grids.

  3. Application for Single Price Auction Model (SPA) in AC Network

    Science.gov (United States)

    Wachi, Tsunehisa; Fukutome, Suguru; Chen, Luonan; Makino, Yoshinori; Koshimizu, Gentarou

    This paper aims to develop a single price auction model with AC transmission network, based on the principle of maximizing social surplus of electricity market. Specifically, we first formulate the auction market as a nonlinear optimization problem, which has almost the same form as the conventional optimal power flow problem, and then propose an algorithm to derive both market clearing price and trade volume of each player even for the case of market-splitting. As indicated in the paper, the proposed approach can be used not only for the price evaluation of auction or bidding market but also for analysis of bidding strategy, congestion effect and other constraints or factors. Several numerical examples are used to demonstrate effectiveness of our method.

  4. FLUXCAP: A flux-coupled ac/dc magnetizing device

    CERN Document Server

    Gopman, Daniel B; Kent, Andrew D

    2012-01-01

    We report on an instrument for applying ac and dc magnetic fields by capturing the flux from a rotating permanent magnet and projecting it between two adjustable pole pieces. This can be an alternative to standard electromagnets for experiments with small samples or in probe stations in which an applied magnetic field is needed locally, with advantages that include a compact form-factor, very low power requirements and dissipation as well as fast field sweep rates. This flux capture instrument (FLUXCAP) can produce fields from -400 to +400 mT, with field resolution less than 1 mT. It generates static magnetic fields as well as ramped fields, with ramping rates as high as 10 T/s. We demonstrate the use of this apparatus for studying the magnetotransport properties of spin-valve nanopillars, a nanoscale device that exhibits giant magnetoresistance.

  5. The ACS LCID Project: overview and first results

    CERN Document Server

    Gallart, Carme

    2007-01-01

    The star formation history (SFH) of Local Group galaxies is a powerful tool for studying their evolution, including chemical enrichment histories and stellar population gradients, which in turn may shed light on the role of reionization or Supernovae feedback in galaxy formation and evolution. In particular, isolated dwarfs are ideal laboratories since their evolution has not been complicated by the vicinity of giant galaxies. In this paper, we present the project Local Cosmology from Isolated Dwarfs (LCID), aimed at deriving detailed SFHs for a sample of Local Group isolated dwarf galaxies. To accomplish this goal we have collected, using the ACS on board the HST, color-magnitude diagrams (CMD) reaching their oldest main sequence turnoff (V~28 or M_V~+3.5) with good photometric accuracy. Some preliminary results from the CMDs are shown and briefly discussed.

  6. Water treatment by the AC gliding arc air plasma

    Science.gov (United States)

    Gharagozalian, Mehrnaz; Dorranian, Davoud; Ghoranneviss, Mahmood

    2017-06-01

    In this study, the effects of gliding arc (G Arc) plasma system on the treatment of water have been investigated experimentally. An AC power supply of 15 kV potential difference at 50 Hz frequency was employed to generate plasma. Plasma density and temperature were measured using spectroscopic method. The water was contaminated with staphylococcus aureus (Gram-positive) and salmonella bacteria (Gram-negative), and Penicillium (mold fungus) individually. pH, hydrogen peroxide, and nitride contents of treated water were measured after plasma treatment. Decontamination of treated water was determined using colony counting method. Results indicate that G Arc plasma is a powerful and green tool to decontaminate water without producing any byproducts.

  7. Cluster emission in the radioactive decay of 223Ac

    CERN Document Server

    Steyn, G F; Faccio, D; Bonetti, R; Tretyakova, S P; Shishkin, S V; Ogloblin, A A; Pik-Pichak, G A; Vermeulen, C; van der Meulen, N P; van der Walt, T N; McGee, D

    2010-01-01

    The branching ratio of 223Ac decay by spontaneous 14C emission was measured and a search for 15N clusters was performed. After exposure of a hemispherical array of solid-state nuclear track detectors, 347 14C events were identified and no 15N events. B(14C) = λ(14C)/λ(α) = (3.2 ± 1.0) x 10-11 is consistent with a favoured ground state to ground state transition. As no nitrogen tracks were found, only an upper limit could be inferred for 15N emission, B(15N) = λ(15N)/λ(α) ≤ 2.2 x 10-13 (confidence limit 90%), consistent with an unfavoured transition. Intense 227Pa sources were produced for this study, using the reaction 232Th(p,6n)227Pa. This offered an opportunity to compare the measured source strength with predictions based on published excitation function data.

  8. Nonlinearity exponent of ac conductivity in disordered systems

    Science.gov (United States)

    Nandi, U. N.; Sircar, S.; Karmakar, A.; Giri, S.

    2012-07-01

    We measured the real part of ac conductance Σ(x,f) or Σ(T,f) of iron-doped mixed-valent polycrystalline manganite oxides LaMn1-xFexO3 as a function of frequency f by varying initial conductance Σ0 by quenched disorder x at a fixed temperature T (room) and by temperature T at a fixed quenched disorder x. At a fixed temperature T, Σ(x,f) of a sample with fixed x remains almost constant at its zero-frequency dc value Σ0 at lower frequency. With increase in f, Σ(x,f) increases slowly from Σ0 and finally increases rapidly following a power law with an exponent s at high frequency. Scaled appropriately, the data for Σ(T,f) and Σ(x,f) fall on the same universal curve, indicating the existence of a general scaling formalism for the ac conductivity in disordered systems. The characteristic frequency fc at which Σ(x,f) or Σ(T,f) increases for the first time from Σ0 scales with initial conductance Σ0 as {f}_{{c}}\\sim {\\Sigma }_{0}^{{x}_{f}}, where xf is the onset exponent. The value of xf is nearly equal to one and is found to be independent of x and T. Further, an inverse relationship between xf and s provides a self-consistency check of the systematic description of Σ(x,f) or Σ(T,f). This apparent universal value of xf is discussed within the framework of existing theoretical models and scaling theories. The relevance to other similar disordered systems is also highlighted.

  9. Moderately nonlinear diffuse-charge dynamics under an ac voltage

    Science.gov (United States)

    Stout, Robert F.; Khair, Aditya S.

    2015-09-01

    The response of a symmetric binary electrolyte between two parallel, blocking electrodes to a moderate amplitude ac voltage is quantified. The diffuse charge dynamics are modeled via the Poisson-Nernst-Planck equations for a dilute solution of point-like ions. The solution to these equations is expressed as a Fourier series with a voltage perturbation expansion for arbitrary Debye layer thickness and ac frequency. Here, the perturbation expansion in voltage proceeds in powers of Vo/(kBT /e ) , where Vo is the amplitude of the driving voltage and kBT /e is the thermal voltage with kB as Boltzmann's constant, T as the temperature, and e as the fundamental charge. We show that the response of the electrolyte remains essentially linear in voltage amplitude at frequencies greater than the RC frequency of Debye layer charging, D /λDL , where D is the ion diffusivity, λD is the Debye layer thickness, and L is half the cell width. In contrast, nonlinear response is predicted at frequencies below the RC frequency. We find that the ion densities exhibit symmetric deviations from the (uniform) equilibrium density at even orders of the voltage amplitude. This leads to the voltage dependence of the current in the external circuit arising from the odd orders of voltage. For instance, the first nonlinear contribution to the current is O (Vo3) which contains the expected third harmonic but also a component oscillating at the applied frequency. We use this to compute a generalized impedance for moderate voltages, the first nonlinear contribution to which is quadratic in Vo. This contribution predicts a decrease in the imaginary part of the impedance at low frequency, which is due to the increase in Debye layer capacitance with increasing Vo. In contrast, the real part of the impedance increases at low frequency, due to adsorption of neutral salt from the bulk to the Debye layer.

  10. Vector control of three-phase AC machines system development in the practice

    CERN Document Server

    Quang, Nguyen Phung

    2008-01-01

    Covers the area of vector control of 3-phase AC machines, in particular induction motors with squirrel-cage rotor, permanent excited synchronous motors and doubly-fed induction machines. This title summarizes the basic structure of a field-oriented controlled 3-phase AC drive and grid voltage orientated controlled wind power plant.

  11. Recovery of consciousness in broilers following combined dc and ac stunning

    Science.gov (United States)

    Broilers in the United States are typically electrically stunned using low voltage-high frequency pulsed DC water bath stunners and in the European Union broilers are electrocuted using high voltage-low frequency AC. DC stunned broilers regain consciousness in the absence of exsanguination and AC st...

  12. Single phase AC-DC power factor corrected converter with high frequency isolation using buck converter

    Directory of Open Access Journals (Sweden)

    R. Ramesh,

    2014-03-01

    Full Text Available Single phase ac-dc converters having high frequency isolation are implemented in buck, boost, buck-boost configuration with improving the power quality in terms of reducing the harmonics of input current. The paperpropose the circuit configuration, control mechanism, and simulation result for the single phase ac-dc converter.

  13. Fe-aminoclay-entrapping electrospun polyacrylonitrile nanofibers (FeAC-PAN NFs) for environmental engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Young [Korea Railroad Research Institute, Uiwang (Korea, Republic of); Choi, Saehae [Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Park, Seung Bin [KAIST, Daejeon (Korea, Republic of); Kim, Mooon Il; Lee, Young Chul [Gachon Univ., Seongnam (Korea, Republic of); Lee, Go Woon [KIER, Daejeon (Korea, Republic of); Lee, Hyun Uk [Korea Basic Science Institute, Daejeon (Korea, Republic of)

    2015-09-15

    Electrospun polyacrylonitrile nanofibers (PAN NFs) with entrapped water-soluble Fe-aminoclay (FeAC) [FeAC-PAN NFs] were prepared. Slow dropwise addition of water-soluble FeAC into a PAN solution, less aggregated of FeAC into electrospun PAN NFs was one-pot evolved without FeAC post-decoration onto as-prepared PAN NFs. Taking into consideration both the Fe{sup 3+} source in FeAC and the improved surface hydrophilicity, the feasibility of Fentonlike reaction for decolorization of cationic model dye methylene blue (MB) under 6 hrs UV-light irradiation was established. In the case where FeAC-PAN NFs were enhanced by hydrogen peroxide (H{sub 2}O{sub 2}) injection, the apparent kinetic reaction rates were increased relative to those for the PAN NFs. Thus, our flexible FeAC-PAN NF mats can be effectively utilized in water/waste treatment and other environmental engineering applications.

  14. Are BVS suitable for ACS patients? Support from a large single center real live registry

    NARCIS (Netherlands)

    C. Felix (Cordula); Y. Onuma (Yoshinobu); J.M. Fam (Jiang Ming); R. Diletti (Roberto); Y. Ishibashi (Yuki); A. Karanasos (Antonios); B. Everaert (Bert); N.M. van Mieghem (Nicolas); J. Daemen (Joost); P.P.T. de Jaegere (Peter); F. Zijlstra (Felix); E.S. Regar (Eveline); R.J.M. van Geuns (Robert Jan)

    2016-01-01

    textabstractObjectives To investigate one-year outcomes after implantation of a bioresorbable vascular scaffold (BVS) in patients presenting with acute coronary syndrome (ACS) compared to stable angina patients. Background Robust data on the outcome of BVS in the setting of ACS is still scarce.

  15. AC-Specific Heat and Heat Conductivity Derived from Thermal Effusivity Measurements

    DEFF Research Database (Denmark)

    Christensen, Tage Emil

    It is shown how the 3-omega technique of AC-calorimetry applied to a plane heater with finite dimensions can be improved by including boundary effects.......It is shown how the 3-omega technique of AC-calorimetry applied to a plane heater with finite dimensions can be improved by including boundary effects....

  16. Measuring ac-loss in high temperature superconducting cable-conductors using four probe methods

    DEFF Research Database (Denmark)

    Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten; Olsen, Søren Krüger;

    1999-01-01

    Measuring the ac-loss of superconducting cable conductors have many aspects in common with measuring the ac-loss of single superconducting tapes. In a cable conductor all tapes are connected to each other and to the test circuit through normal metal joints in each end. This makes such measurement...

  17. Substituted Phthalimide AC94377 Is a Selective Agonist of the Gibberellin Receptor GID11[OPEN

    Science.gov (United States)

    Otani, Masato; Shimotakahara, Hiroaki; Yoon, Jung-Min; Park, Seung-Hyun; Miyaji, Tomoko; Nakano, Takeshi; Nakamura, Hidemitsu; Nakajima, Masatoshi

    2017-01-01

    Gibberellin (GA) is a major plant hormone that regulates plant growth and development and is widely used as a plant growth regulator in agricultural production. There is an increasing demand for function-limited GA mimics due to the limitations on the agronomical application of GA to crops, including GA’s high cost of producing and its leading to the crops’ lodging. AC94377, a substituted phthalimide, is a chemical that mimics the growth-regulating activity of GAs in various plants, despite its structural difference. Although AC94377 is widely studied in many weeds and crops, its mode of action as a GA mimic is largely unknown. In this study, we confirmed that AC94377 displays GA-like activities in Arabidopsis (Arabidopsis thaliana) and demonstrated that AC94377 binds to the Arabidopsis GIBBERELLIN INSENSITIVE DWARF1 (GID1) receptor (AtGID1), forms the AtGID1-AC94377-DELLA complex, and induces the degradation of DELLA protein. Our results also indicated that AC94377 is selective for a specific subtype among three AtGID1s and that the selectivity of AC94377 is attributable to a single residue at the entrance to the hydrophobic pocket of GID1. We conclude that AC94377 is a GID1 agonist with selectivity for a specific subtype of GID1, which could be further developed and used as a function-limited regulator of plant growth in both basic study and agriculture. PMID:27899534

  18. Risk prediction of ventricular arrhythmias and myocardial function in Lamin A/C mutation positive subjects

    DEFF Research Database (Denmark)

    Hasselberg, Nina E; Edvardsen, Thor; Petri, Helle;

    2014-01-01

    Mutations in the Lamin A/C gene may cause atrioventricular block, supraventricular arrhythmias, ventricular arrhythmias (VA), and dilated cardiomyopathy. We aimed to explore the predictors and the mechanisms of VA in Lamin A/C mutation-positive subjects.METHODS AND RESULTS: We included 41 Lamin A...

  19. The ACS Exams Institute Undergraduate Chemistry Anchoring Concepts Content Map I: General Chemistry

    Science.gov (United States)

    Holme, Thomas; Murphy, Kristen

    2012-01-01

    To provide tools for programmatic assessment related to the use of ACS Exams in undergraduate chemistry courses, the ACS Exams Institute has built a content map that applies to the entire undergraduate curriculum. At the top two levels, the grain size of the content classification is large and spans the entire undergraduate curriculum. At the…

  20. A Simplified Model to Calculate AC Losses in Large 2G HTS Coils

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Jensen, Bogi Bech;

    2015-01-01

    AC losses are of great significance to quantify the performance of high temperature superconducting (HTS) devices. This paper presents a simplified model to calculate AC losses in large 2G HTS coils, which serves as a baseline to study HTS large scale applications such as electric machines. The m...

  1. Performance Analysis of Phase Controlled Unidirectional and Bidirectional AC Voltage Controllers

    Directory of Open Access Journals (Sweden)

    Abdul Sattar Larik

    2011-01-01

    Full Text Available AC voltage controllers are used to vary the output ac voltage from a fixed ac input source. They are also commonly called ac voltage regulators or ac choppers. The output voltage is either controlled by PAC (Phase Angle Control method or on-off control method. Due to various advantages of ac voltage controllers, such as high efficiency, simplicity, low cost and ability to control large amount of power they efficiently control the speed of ac motors, light dimming and industrial heating, etc. These converters are variable structure systems and generate harmonics during the operation which will affect the power quality when connected to system network. During the last couple of years, a number of new semiconductor devices and various power electronic converters has been introduced. Accordingly the subject of harmonics and its problems are of great concern to power industry and customers. In this research work, initially the simulation models of single phase unidirectional and bidirectional ac voltage controllers were developed by using MATLAB software. The harmonics of these models are investigated by simulation. In the end, the harmonics were also analyzed experimentally. The simulated as well as experimental results are presented.

  2. The ACS Exams Institute Undergraduate Chemistry Anchoring Concepts Content Map I: General Chemistry

    Science.gov (United States)

    Holme, Thomas; Murphy, Kristen

    2012-01-01

    To provide tools for programmatic assessment related to the use of ACS Exams in undergraduate chemistry courses, the ACS Exams Institute has built a content map that applies to the entire undergraduate curriculum. At the top two levels, the grain size of the content classification is large and spans the entire undergraduate curriculum. At the…

  3. ACCE/ACS National Educator and Leader of the Year Winners: AEC Congratulates These Outstanding Educators

    Science.gov (United States)

    Australian Educational Computing, 2012

    2012-01-01

    This article presents the ACCE/ACS National Educator and Leader of the Year winners. Anne Mirtschin is the recipient of the ACCE/ACS 2012 Educator of the Year Award. Mirtschin is an innovative teacher at Hawkesdale P-12 College a small rural school that is isolated culturally and geographically. She uses online tools and technology to create…

  4. Drug-eluting stents and bare metal stents in patients with NSTE-ACS

    DEFF Research Database (Denmark)

    Pedersen, Sune Haahr; Pfisterer, Matthias; Kaiser, Christoph;

    2014-01-01

    Aims: The use of drug-eluting stents (DES) in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) is controversial and not yet endorsed in clinical guidelines. Methods and results: This was an a priori planned post hoc analysis involving 754 NSTE-ACS patients from the random...

  5. Investigations on gradient a.c. conductivity characteristics of bamboo (Dendrocalamus strictus)

    Indian Academy of Sciences (India)

    Navin Chand; Deepak Jain; Archana Nigrawal

    2006-04-01

    Effect of temperature and frequency variation on a.c. conductivity of bamboo was determined by using a 4274 A Multi-Frequencies LCR meter. Electrical measurements were carried out in the temperature range 24–120°C and in the frequency range 4–100 kHz. It was observed that the a.c. conductivity increased initially and then decreased with increase of temperature and frequencies. The increase of distance from outer surface to the inner surface side increased the a.c. conductivity values and showed the grading in a.c. conductivity behaviour. Two phases of a.c. conductivity behaviour with temperature exist in bamboo. At 10 mm distance a.c. conductivity suddenly increases which is the critical depth from skin for this bamboo. Increase of temperature, at all the frequencies increases the a.c. conductivity initially and then decreases. Downward peaks in a.c. conductivities are observed at all the frequencies due to the presence of moisture in bamboo, which liberated on heating. Sharp peak is observed in case of sample 4, which is inner most strip. Maximum sharp peak is observed at lowest 4 kHz frequency.

  6. A Computer Model for Teaching the Dynamic Behavior of AC Contactors

    Science.gov (United States)

    Ruiz, J.-R. R.; Espinosa, A. G.; Romeral, L.

    2010-01-01

    Ac-powered contactors are extensively used in industry in applications such as automatic electrical devices, motor starters, and heaters. In this work, a practical session that allows students to model and simulate the dynamic behavior of ac-powered electromechanical contactors is presented. Simulation is carried out using a rigorous parametric…

  7. The HST/ACS Coma Cluster Survey : II. Data Description and Source Catalogs

    NARCIS (Netherlands)

    Hammer, Derek; Kleijn, Gijs Verdoes; Hoyos, Carlos; den Brok, Mark; Balcells, Marc; Ferguson, Henry C.; Goudfrooij, Paul; Carter, David; Guzman, Rafael; Peletier, Reynier F.; Smith, Russell J.; Graham, Alister W.; Trentham, Neil; Peng, Eric; Puzia, Thomas H.; Lucey, John R.; Jogee, Shardha; Aguerri, Alfonso L.; Batcheldor, Dan; Bridges, Terry J.; Chiboucas, Kristin; Davies, Jonathan I.; del Burgo, Carlos; Erwin, Peter; Hornschemeier, Ann; Hudson, Michael J.; Huxor, Avon; Jenkins, Leigh; Karick, Arna; Khosroshahi, Habib; Kourkchi, Ehsan; Komiyama, Yutaka; Lotz, Jennifer; Marzke, Ronald O.; Marinova, Irina; Matkovic, Ana; Merritt, David; Miller, Bryan W.; Miller, Neal A.; Mobasher, Bahram; Mouhcine, Mustapha; Okamura, Sadanori; Percival, Sue; Phillipps, Steven; Poggianti, Bianca M.; Price, James; Sharples, Ray M.; Tully, R. Brent; Valentijn, Edwin

    2010-01-01

    The Coma cluster, Abell 1656, was the target of an HST-ACS Treasury program designed for deep imaging in the F475W and F814W passbands. Although our survey was interrupted by the ACS instrument failure in early 2007, the partially completed survey still covers ~50% of the core high-density region in

  8. The HST/ACS Coma Cluster Survey. II. Data Description and Source Catalogs

    NARCIS (Netherlands)

    Hammer, Derek; Verdoes Kleijn, Gijs; Hoyos, Carlos; den Brok, Mark; Balcells, Marc; Ferguson, Henry C.; Goudfrooij, Paul; Carter, David; Guzmán, Rafael; Peletier, Reynier F.; Smith, Russell J.; Graham, Alister W.; Trentham, Neil; Peng, Eric; Puzia, Thomas H.; Lucey, John R.; Jogee, Shardha; Aguerri, Alfonso L.; Batcheldor, Dan; Bridges, Terry J.; Chiboucas, Kristin; Davies, Jonathan I.; del Burgo, Carlos; Erwin, Peter; Hornschemeier, Ann; Hudson, Michael J.; Huxor, Avon; Jenkins, Leigh; Karick, Arna; Khosroshahi, Habib; Kourkchi, Ehsan; Komiyama, Yutaka; Lotz, Jennifer; Marzke, Ronald O.; Marinova, Irina; Matkovic, Ana; Merritt, David; Miller, Bryan W.; Miller, Neal A.; Mobasher, Bahram; Mouhcine, Mustapha; Okamura, Sadanori; Percival, Sue; Phillipps, Steven; Poggianti, Bianca M.; Price, James; Sharples, Ray M.; Tully, R. Brent; Valentijn, Edwin

    2010-01-01

    The Coma cluster, Abell 1656, was the target of an HST-ACS Treasury program designed for deep imaging in the F475W and F814W passbands. Although our survey was interrupted by the ACS instrument failure in early 2007, the partially completed survey still covers ~50% of the core high-density region in

  9. Qualitative and Quantitative Coronary Angiography in patients with Acute Coronary Syndrome (ACS

    Directory of Open Access Journals (Sweden)

    Ahmed H.H. El-Adawey

    2012-07-01

    Conclusion: The qualitative angiographic assessment represents an essential tool in the evaluation and risk stratification of patients with ACS, through the demonstration of the presence of thrombus and lumen irregularity that correlated more with ACS than the other studded criteria. In addition, QCA although added accurate assessment of the degree of luminal narrowing, thus helping in assessment of the severity of the disease.

  10. Mapping entrained brain oscillations during transcranial alternating current stimulation (tACS)

    NARCIS (Netherlands)

    Witkowski, M.; Garcia Cossio, E.; Chander, B.S.; Braun, C.; Birbaumer, N.; Robinson, S.E.; Soekadar, S.R.

    2016-01-01

    Transcranial alternating current stimulation (tACS), a non-invasive and well-tolerated form of electric brain stimulation, can influence perception, memory, as well as motor and cognitive function. While the exact underlying neurophysiological mechanisms are unknown, the effects of tACS are mainly

  11. Measurement of AC losses in a racetrack superconducting coil made from YBCO coated conductor

    DEFF Research Database (Denmark)

    Seiler, Eugen; Abrahamsen, Asger Bech; Kovac, Jan

    2012-01-01

    to reinforce it. The AC loss is measured versus the transport current Ia with the coil immersed in liquid nitrogen. Measurements at frequencies 21 Hz, 36 Hz and 72 Hz are compared. The AC losses follow I2 a dependence at low current amplitudes and I3 a at high amplitudes. After cutting the inner steel frame...

  12. Improved Tribological Performance of Amorphous Carbon (a-C Coating by ZrO2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Jinzhu Tang

    2016-09-01

    Full Text Available Nanomaterials, such as Graphene, h-BN nanoparticles and MoS2 nanotubes, have shown their ability in improving the tribological performance of amorphous carbon (a-C coatings. In the current study, the effectiveness of ZrO2 nanoparticles (ZrO2-NPs in lubricating the self-mated nonhydrogenated a-C contacts was investigated in boundary lubrication regime. The results showed that 13% less friction and 50% less wear compared to the base oil were achieved by employing ZrO2-NPs in the base oil in self-mated a-C contacts. Via analyzing the ZrO2-NPs and the worn a-C surface after tests, it was found that the improved lubrication by ZrO2-NPs was based on “polishing effects”, which is a new phenomenon observed between a-C and nanoparticles. Under the “polishing effect”, micro-plateaus with extremely smooth surface and uniform height were produced on the analyzed a-C surface. The resulting topography of the a-C coating is suitable for ZrO2-NPs to act as nano-bearings between rubbing surfaces. Especially, the ZrO2-NPs exhibited excellent mechanical and chemical stability, even under the severe service condition, suggesting that the combination of nonhydrogenated a-C coating with ZrO2-NPs is an effective, long lasting and environment-friendly lubrication solution.

  13. Electrocardiographic left ventricular hypertrophy in GUSTO IV ACS: an important risk marker of mortality in women

    DEFF Research Database (Denmark)

    Westerhout, Cynthia M; Lauer, Michael S; Fu, Yuling

    2007-01-01

    AIM: To examine the association of left ventricular hypertrophy (LVH) on admission electrocardiography with adverse outcomes in acute coronary syndrome (ACS) patients. METHODS AND RESULTS: A total of 7443 non-ST-elevation ACS patients in Global Utilization of STrategies to Open occluded arteries...

  14. Resveratrol inhibits mucus overproduction and MUC5AC expression in a murine model of asthma.

    Science.gov (United States)

    Ni, Zhen-Hua; Tang, Ji-Hong; Chen, Guo; Lai, Yi-Min; Chen, Qing-Ge; Li, Zao; Yang, Wei; Luo, Xu-Min; Wang, Xiong-Biao

    2016-01-01

    Previous in vitro studies have demonstrated that resveratrol is able to significantly inhibit the upregulation of mucin 5AC (MUC5AC), a major component of mucus; thus indicating that resveratrol may have potential in regulating mucus overproduction. However, there have been few studies regarding the resveratrol‑mediated prevention of MUC5AC overproduction in vivo, and the mechanisms by which resveratrol regulates MUC5AC expression have yet to be elucidated. In the present study, an ovalbumin (OVA)‑challenged murine model of asthma was used to assess the effects of resveratrol treatment on mucus production in vivo. The results demonstrated that resveratrol significantly inhibited OVA‑induced airway inflammation and mucus production. In addition, the mRNA and protein expression levels of MUC5AC were increased in the OVA‑challenged mice, whereas treatment with resveratrol significantly inhibited this effect. The expression levels of murine calcium‑activated chloride channel (mCLCA)3, an important key mediator of MUC5AC production, were also reduced following resveratrol treatment. Furthermore, in vitro studies demonstrated that resveratrol significantly inhibited human (h)CLCA1 and MUC5AC expression in a dose‑dependent manner. These results indicated that resveratrol was effective in preventing mucus overproduction and MUC5AC expression in vivo, and its underlying mechanism may be associated with regulation of the mCLCA3/hCLCA1 signaling pathway.

  15. A Sufficient Condition on Convex Relaxation of AC Optimal Power Flow in Distribution Networks

    DEFF Research Database (Denmark)

    Huang, Shaojun; Wu, Qiuwei; Wang, Jianhui;

    2016-01-01

    solution of the SOCP can be converted to an optimal solution of the original AC OPF. The efficacy of the convex relaxation to solve the AC OPF is demonstrated by case studies of an optimal multi-period planning problem of electric vehicles (EVs) in distribution networks....

  16. Nuclear Structure Effects in the Exotic Decay of $^{225}$Ac via $^{14}$C Emission

    CERN Multimedia

    2002-01-01

    % IS323 \\\\ \\\\ We propose to build at Isolde a high intensity $^{225}$Ac source by $\\beta$-decay of $^{225}$(Ra+Fr) beam, to be used at the superconducting spectrometer SOLENO of IPN-Orsay in order to study a possible fine structure in the spectrum of $^{14}$C ions spontaneously emitted by $^{225}$Ac.

  17. AC loss measurements in HTS coil assemblies with hybrid coil structures

    Science.gov (United States)

    Jiang, Zhenan; Long, Nicholas J.; Staines, Mike; Badcock, Rodney A.; Bumby, Chris W.; Buckley, Robert G.; Amemiya, Naoyuki

    2016-09-01

    Both AC loss and wire cost in coil windings are critical factors for high temperature superconductor (HTS) AC machinery applications. We present AC loss measurement results in three HTS coil assemblies at 77 K and 65 K which have a hybrid coil structure comprising one central winding (CW) and two end windings (EWs) wound with ReBCO and BSCCO wires with different self-field I c values at 77 K. All AC loss results in the coil assemblies are hysteretic and the normalized AC losses in the coil assemblies at different temperatures can be scaled with the I c value of the coil assemblies. The normalised results show that AC loss in a coil assembly with BSCCO CW can be reduced by using EWs wound with high I c ReBCO wires, whilst further AC loss reduction can be achieved by replacing the BSCCO CW with ReBCO CW. The results imply that a flexible hybrid coil structure is possible which considers both AC loss and wire cost in coil assemblies.

  18. Control the aggregation of model amyloid insulin protein under ac-electric fields

    Science.gov (United States)

    Zheng, Zhongli; Jing, Benxin; Zhu, Y. Elaine

    2013-03-01

    In vitro experiments have been widely used to characterize the misfolding/unfolding pathway characteristic of amylodogenic proteins. Conversion from natively folded amyloidogenic proteins to oligomers via nucleation is the accepted path to fibril formation upon heating over a certain lag time period. In an alternative engineering approach to manipulate and control protein aggregation, we have investigated the aggregation kinetics of insulin, a well-established amyloid model protein, under applied ac-electric fields of varied ac-frequency and voltage at room temperature. Using fluorescence correlation spectroscopy and fluorescence imaging, we have observed that the insulin aggregation can occur at much shortened lag time under applied ac-electric fields, when a critical ac-voltage is exceeded. The strong dependence of lag time on ac-frequency over a narrow range of 500 Hz-5 kHz indicates the effect of ac-electroosmosis on the diffusion controlled process of insulin nucleation. Yet, no difference of conformational structure is detected with insulin under applied ac-fields, suggesting the equivalence of ac-polarization to the conventional thermal activation process for insulin aggregation.

  19. Distributed Control for Autonomous Operation of a Three-Port AC/DC/DS Hybrid Microgrid

    DEFF Research Database (Denmark)

    Wang, Peng; Jin, Chi; Zhu, Dexuan

    2015-01-01

    This paper presents a distributed control scheme for reliable autonomous operation of a hybrid three-port ac/dc/distributed storage (ds) microgrid by means of power sharing in individual network, power exchange between ac and dc networks, and power management among three networks. The proposed...

  20. Tumor-associated MUC5AC stimulates in vivo tumorigenicity of human pancreatic cancer.

    Science.gov (United States)

    Hoshi, Hirotaka; Sawada, Tetsuji; Uchida, Motoyuki; Saito, Hikaru; Iijima, Hiroko; Toda-Agetsuma, Mikako; Wada, Tsutomu; Yamazoe, Sadaaki; Tanaka, Hiroaki; Kimura, Kenjiro; Kakehashi, Anna; Wei, Min; Hirakawa, Kosei; Wanibuchi, Hideki

    2011-03-01

    MUC5AC, a high molecular weight glycoprotein, is overexpressed in the ductal region of human pancreatic cancer but is not detectable in the normal pancreas, suggesting its association with disease development. In the present study, we investigated the in vitro and in vivo effects of MUC5AC knockdown by short interfering RNA (siRNA) in the MUC5AC-overexpressing SW1990 and BxPC3 human pancreatic cancer cell lines in order to clarify its function. Significant decreases in the expression levels of MUC5AC mRNA and protein were observed in SW1990 and BxPC3 cells that had been stably transfected with a MUC5AC siRNA expression vector (SW1990/si-MUC5AC and BxPC3/si-MUC5AC cells) compared to those in cells transfected with an si-mock vector (SW1990/si-mock and BxPC3/si-mock cells). In in vitro studies, neither type of MUC5AC-knockdown cell showed any difference in cell survival, proliferation, or morphology from the si-mock cells or parental cells. However, in vivo xenograft studies demonstrated that MUC5AC knockdown significantly reduced the tumorigenicity and suppressed the tumor growth of si-MUC5AC cells compared to those of the si-mock cells. Immunohistochemical analysis revealed that CD45R/B220+ and Gr-1+ cells had infiltrated into the tumor tissue of the SW1990/si-MUC5AC cells. Furthermore, cancer-associated antigen specific antibodies were detected at high levels in the sera from the SW1990/si-MUC5AC cell-bearing mice. These results suggest that tumor-associated MUC5AC expressed on the surface of pancreatic cancer cells supports the escape of pancreatic cancer cells from immunosurveillance. The present findings highlight a new dimension of MUC5AC as a functional immunosuppressive agent and its important role in pancreatic cancer progression.