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Sample records for ac systems

  1. AC power supply systems

    An ac power supply system includes a rectifier fed by a normal ac supply, and an inverter connected to the rectifier by a dc link, the inverter being effective to invert the dc output of the receiver at a required frequency to provide an ac output. A dc backup power supply of lower voltage than the normal dc output of the rectifier is connected across the dc link such that the ac output of the rectifier is derived from the backup supply if the voltage of the output of the inverter falls below that of the backup supply. The dc backup power may be derived from a backup ac supply. Use in pumping coolant in nuclear reactor is envisaged. (author)

  2. ac propulsion system for an electric vehicle

    Geppert, S.

    1980-01-01

    It is pointed out that dc drives will be the logical choice for current production electric vehicles (EV). However, by the mid-80's, there is a good chance that the price and reliability of suitable high-power semiconductors will allow for a competitive ac system. The driving force behind the ac approach is the induction motor, which has specific advantages relative to a dc shunt or series traction motor. These advantages would be an important factor in the case of a vehicle for which low maintenance characteristics are of primary importance. A description of an EV ac propulsion system is provided, taking into account the logic controller, the inverter, the motor, and a two-speed transmission-differential-axle assembly. The main barrier to the employment of the considered propulsion system in EV is not any technical problem, but inverter transistor cost.

  3. AC motor drive system for electric cars

    Morohoshi, Yukinobu; Yoshinori, Naoto; Naito, Hironobu (Fuji Electric Co., Ltd., Tokyo, (Japan))

    1989-08-10

    Various main circuit equipment with large capacity GTO thyristors are outlined for AC and DC electric cars. The configuration of a PWM converter system is presented for the AC main motor drive system of the Shinkansen trains, and its following features are described: the high power factor control capable of keeping a power factor 100% constantly, energy saving by power regenerative braking, the small triple structure with large capacity reverse-conducting GTO thyristors of 4,500V/3,000A, and the reduction of equivalent interfering current and harmonic current by three phase-triple phase difference operation. Furthermore, a control logic equipment with 16 bit MPU and a main transformer are outlined, and the verification test results of the control logic equipment by an analog model simulation and the combinational test results of the commercial equipment are reported. Prototype VVVF inverter system for DC electric cars is also presented. 6 refs., 13 figs., 3 tabs.

  4. Flexible AC transmission systems modelling and control

    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

  5. A Simple Load Power Estimator For Quasi-Direct AC-AC Converter System

    Marian GAICEANU; Emil ROSU

    2003-01-01

    In this paper a simple load power estimator for the three-phase quasi-direct acac converter system is reported. Since the ac-ac converter control by means of pulsewidth modulation (PWM) is based on the power balance concept, its load power should be known. Two control boards, based on the dSMC (digital Smart Motion Controller) 30 MIPS 32-bit fixed-point digital signal processor (DSP), were involved in the ac-ac system driving. By using the power balance control, the DC link voltage variation ...

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

    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.

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

    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.

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

    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.

  9. Nonlinear ac conductivity of interacting 1d electron systems

    Rosenow, Bernd; Nattermann, Thomas

    2004-01-01

    We consider low energy charge transport in one-dimensional (1d) electron systems with short range interactions under the influence of a random potential. Combining RG and instanton methods, we calculate the nonlinear ac conductivity and discuss the crossover between the nonanalytic field dependence of the electric current at zero frequency and the linear ac conductivity at small electric fields and finite frequency.

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

    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.

  11. Behaviour analysis of AC-600 passive safety systems

    Southwest Center of Reactor Engineering Research and Design has finished the first step conceptual design of 600 mwe advanced PWR (AC-600). The main research emphases of AC-600 conceptual design include the advanced reactor core, the passive safety systems and the simplification. The passive safety systems of AC-600 consist of two reactor make up water tanks, two accumulators, two emergency feedwater tanks, two emergency natural draft air condensers, a containment water jacket and an enhanced primary cycle natural circulation flow system. 25% of the rated reactor power can be removed by the natural circulation cooling. The full pressure reactor make up water tanks are able to provide enough borated water which would be injected into the reactor coolant system during small LOCA. The coolant natural circulations can be established in the primary system and the passive secondary emergency feedwater system, removing residual heat from the reactor core to the atmosphere when station blackout occurs. It is indicated from analysis that the containment diameter of AC-600 is about 35 m. The large tanks and the large vertical distances between the tanks and reactor core are the main reason of using the big containment. It is also indicated from analysis that the low head safety injection pumps are required in AC-600 design to assure the recirculation system operation when large LOCA occurs. The reliability of AC-600 engineered safety systems is increased because the function of the passive safety systems is conducted through the immutable natural laws. The paper discusses the natural circulation ability and safety behavior of the passive safety systems during LOCA or station blackout for AC-600. The passive limits to excess reactivity and thermal hydraulic transients are also preliminarily discussed. Figs and tabs

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

    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

  13. A Simple Load Power Estimator For Quasi-Direct AC-AC Converter System

    Marian GAICEANU

    2003-12-01

    Full Text Available In this paper a simple load power estimator for the three-phase quasi-direct acac converter system is reported. Since the ac-ac converter control by means of pulsewidth modulation (PWM is based on the power balance concept, its load power should be known. Two control boards, based on the dSMC (digital Smart Motion Controller 30 MIPS 32-bit fixed-point digital signal processor (DSP, were involved in the ac-ac system driving. By using the power balance control, the DC link voltage variation at the load changes can be reduced. In this way a small DC link capacitor is required to handle the dc voltage error control. The feed-forward (Sul and Lipo, 1990 current component provides fast correction of the reference control to load power variation. In order to obtain the feed-forward current component, the load power must to be known. In this paper the load power is estimated from the dc link, indirectly, through a dc load current estimator. In this way the author overcomes the use of the serial communication between control boards (Gaiceanu, 2004 in order to deliver the load power information from the inverter side. The load current estimator is based on the DC link voltage and on the load current of the supply converter. This method presents certain advantages instead of using measured method, which requires a low pass filter: no time delay, the feed-forward current component has no ripple, no additional hardware, and more fast control response. Through simulation and experimental results the performances of the proposed load current estimator scheme are demonstrated.

  14. Research on AC Variable Frequency Speed Regulation System

    Ou Bing-Xian; Li Qing-Zhong; Yan Jun-Xia

    2013-01-01

    In view of shortcomings existing in shear speed control system, shearer AC speed regulating system is designed and studied. The mathematical model of three-phase asynchronous motor in rotating coordinate system is established, and PWM technology of space vector is discussed. Software and hardware of the asynchronous motor vector control variable frequency speed regulating system are designed. The simulation of system based on Matlab is made and the correctness and feasibility of the sys...

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

    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

  16. Sustainable AC/AC hybrid electrochemical capacitors in aqueous electrolyte approaching the performance of organic systems

    Abbas, Qamar; Babuchowska, Paulina; Frąckowiak, Elżbieta; Béguin, François

    2016-09-01

    A high energy hybrid AC/AC electrochemical capacitor has been realized in aqueous Li2SO4+KI electrolyte mixture. Owing to the redox processes associated with the 2I-/I2 system, the positive electrode operates in narrow potential range and displays high capacity. During prolonged potentiostatic floating at 1.6 V, the hybrid cell demonstrates remarkably stable capacitance and resistance. Analyses by temperature programmed desorption after floating at 1.6 V proved that oxidation of the positive AC electrode is prevented by the use of Li2SO4+KI, which enables the maximum potential of this electrode to be shifted below the water oxidation potential. When charged at 0.2 A g-1 up to U = 1.6 V, the hybrid cell displays a high capacitance of 75 F g-1 (300 F g-1 per mass of one electrode) compared to 47 F g-1 (188 F g-1 per mass of one electrode) for a symmetric cell in Li2SO4. At 0.2 A g-1 up to 1.6 V, the hybrid capacitor in Li2SO4+KI displays an energy density of 26 Wh kg-1 which approaches the energy density of 30.9 Wh kg-1 measured when the same carbon is implemented in a capacitor using TEABF4/ACN electrolyte and charged up to 2.5 V.

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

    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.

  18. Active Harmonics Filtering of Distributed AC System

    Shahbaz, Muhammad

    2012-01-01

    The tendency of connecting the Power Electronic loads and distributed power plants through Power Electronic converters is increasing day by day. These Power Electronic converters and loads are the sources of harmonics and reactive power which greatly affect the performance of the power system network. In a weak power grid, the voltage unbalance and non-sinusoidal regimes are very common. Under such circumstances not only the controllability of the power grid itself but also the controllabilit...

  19. Security analysis of interconnected AC/DC systems

    Eriksson, Robert

    2015-01-01

    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.......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 redistribution of power has a sudden effect on the power-flow in the interconnected ac system. This may cause overloading of lines and transformers resulting in disconnection of equipment, and as a consequence cascading failure. The PTDF is used as a method to analyze and avoid violating limits by in the dc...

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

    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.

  1. The minimization of ac phase noise in interferometric systems

    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 a...... in optics. Thus, the necessity of eliminating the effects of index of refraction fluctuations which degrade the performance of all interferometers is pointed out as the first priority. A substantial decrease of the effects of all vibrating, rotating, or flowing masses (e.g., cooling lines) in direct...

  2. System and Battery Charge Control for PV-Powered AC Lighting Systems

    Kern, G.

    1999-04-01

    This report reviews a number of issues specific to stand-alone AC lighting systems. A review of AC lighting technology is presented, which discusses the advantages and disadvantages of various lamps. The best lamps for small lighting systems are compact fluorescent. The best lamps for intermediate-size systems are high- or low-pressure sodium. Specifications for battery charging and load control are provided with the goal of achieving lamp lifetimes on the order of 16,000 to 24,000 hours and battery lifetimes of 4 to 5 years. A rough estimate of the potential domestic and global markets for stand-alone AC lighting systems is presented. DC current injection tests were performed on high-pressure sodium lamps and the test results are presented. Finally, a prototype system was designed and a prototype system controller (with battery charger and DC/AC inverter) was developed and built.

  3. Application of AC servo motor on the in-core neutron flux instrumentation system

    The application of ac servo motor in the In-Core Neutron Flux Instrumentation System is described. The hardware component of ac servo motor control system is different from the dc motor control system. The effect of two control system on the instrumentation system is compared. The ac servo motor control system can improve the accuracy of the motion control, optimize the speed control and increase the reliability. (authors)

  4. A transgenic system for generation of transposon Ac/Ds-induced chromosome rearrangements in rice

    Yu, Chuanhe; Han, FangPu; Zhang, Jianbo; Birchler, James; Peterson, Thomas

    2012-01-01

    The maize Activator (Ac)/Dissociation (Ds) transposable element system has been used in a variety of plants for insertional mutagenesis. Ac/Ds elements can also generate genome rearrangements via alternative transposition reactions which involve the termini of closely linked transposons. Here, we introduced a transgene containing reverse-oriented Ac/Ds termini together with an Ac transposase gene into rice (Oryza sativa ssp. japonica cv. Nipponbare). Among the transgenic progeny, we identifie...

  5. Optimizing DC Voltage Droop Settings for AC/DC System Interactions

    Eriksson, Robert; Beerten, Jef; Ghandari, Mehrdad; Belmans, Ronnie

    2014-01-01

    In this paper, a methodology is presented to optimize the dc voltage droop settings in a multiterminal voltage-source converter high-voltage direct-current system with respect to the ac system stability. Implementing dc voltage droop control enables having multiple converters assisting the system in case of a converter outage. However, the abrupt power setpoint changes create additional stress in the ac system, especially when multiple converters are connected to the same interconnected ac sy...

  6. GRID-CONNECTECD DOUBLE-STAGE AC-AC POWER CONVERTER FOR CSP RENEWABLE ENERGY SYSTEMS

    Sorrentino, Vincenzo

    2015-01-01

    In the last years the renewable energy sources have known a state of their advanced diffusion considering their advantages compared to the traditional energy sources like fossil fuels. For this reason the combined heat and power (CHP) plant fueled by renewable sources are widely used. The purpose of this Ph.D. thesis is the design of a new Grid-connected Double-Stage AC-DC/DC-AC Power Converter (DSACPC) for a Concentrating Solar plant for Combined generation of Heat and Power (CS-CHP), th...

  7. Research on closed-loop simulation system for digital AC servo system

    HAO ShuangHui; ZHENG WeiFeng; HAO MingHui; MA RuQi; LI Hong

    2009-01-01

    An intelligent and efficient closed-loop simulation system without any hardware is proposed for AC servo system. According to the characteristics of AC servo system and its control processor, the code executing platform combined with the reverse Polish notation algorithm is developed. To gain the accurate simulation results, the discrete motor model and IPM model are built to deal with the dead-time.Based on the simulation system, parameter identification can be implemented and control parameters can be optimized by using the exhaust algorithm. The parameters obtained by the simulation system were successfully applied to an experimental system, and the favorable control performance was achieved.

  8. Flexible AC transmission system devices: allocation and transmission pricing

    The transmission of electricity differs from transportation of any typical commodity by some inherent aspects such as: the production needs to match the consumption at the same time; system control is not an easy task; the electricity flows do not usually follow the economic law. The last aspect is normally observed when transmission systems are included in, for instance, an economic dispatch problem. One way to minimize the operational costs caused by an overloaded transmission system is through the installation of Flexible AC Transmission System (FACTS) devices in the system. They are able to change power flows by modifying the network parameters. This paper focuses on the ability of FACTS devices to change the overall costs of the system and their impact on transmission pricing. The allocation and the determination of the FACTS required are also discussed. Some examples using the IEEE-14 system and the Brazilian electrical system of the Southern region are given to illustrate the concepts introduced in this paper. (author)

  9. An NPV and AC Analysis of a Stochastic Inventory System with Joint Manufacturing and Remanufacturing

    Laan, Erwin

    2000-01-01

    textabstractWhile the net present value (NPV) approach is widely accepted as the right framework for studying production and inventory control systems, average cost (AC) models are more widely used. For the well known EOQ model it can be veri_ed that (under certain conditions) the AC approach gives near optimal results. This paper investigates whether the same holds for two-source systems with joint manufacturing and remanufacturing. It appears that the performance of the AC approach stands o...

  10. Mathematical modeling of Automatic Control System (ACS) and synchronous motor in high reliability power supply systems in Kozloduy NPP - set up optimization of ACS

    The article presents the models of Automatic Control System (ACS) and synchronous motor of the reversible generator-engine groups of the first category power supply section in the Kozloduy NPP units 1 to 4. The control parameter is the magnetic field. The research aims are optimal ACS setups, property control guaranties in accordance with the technical requirements. The used synchronous machine model is included in Matlab5.x library. For optimization the instruments of optimization toolbox - NCD out port block and plant actuator and created basic models of variable Discrete PID-regulator and PWM system are utilized. The results are applied for the setup of the real ACS. The results precision of the created models gives a possibility for a real summary model development and the achieved models implementation in cases of fluctuations of AC/DC reversible electromechanical supply

  11. Mathematical modeling of Automatic Control System (ACS) and synchronous generator in high reliability power supply systems in Kozloduy NPP - set up optimization of ACS

    The article presents the models of Automatic Control System (ACS) and synchronous generator of the reversible generator-engine groups of first category power supply section in the Kozloduy NPP units 1 to 4. The control parameter is the synchronous machine tension. The research aims are optimal ACS setups, property control guaranties in accordance with the technical requirements. The used synchronous machine model is included in Matlab5.x library. For optimization the instruments of optimization toolbox - NCD out port block and plant actuator and created basic models of variable Discrete PID-regulator and PWM system are utilized. The results are applied for the setup of the real ACS. The results precision of the created models gives a possibility for a real summary model development and the achieved models implementation in cases of fluctuations of AC/DC reversible electromechanical supply

  12. On two-liquid AC electroosmotic system for thin films.

    Navarkar, Abhishek; Amiroudine, Sakir; Demekhin, Evgeny A

    2016-03-01

    Lab-on-chip devices employ EOF for transportation and mixing of liquids. However, when a steady (DC) electric field is applied to the liquids, there are undesirable effects such as degradation of sample, electrolysis, bubble formation, etc. due to large magnitude of electric potential required to generate the flow. These effects can be averted by using a time-periodic or AC electric field. Transport and mixing of nonconductive liquids remain a problem even with this technique. In the present study, a two-liquid system bounded by two rigid plates, which act as substrates, is considered. The potential distribution is derived by assuming a Boltzmann charge distribution and using the Debye-Hückel linearization. Analytical solution of this time-periodic system shows some effects of viscosity ratio and permittivity ratio on the velocity profile. Interfacial electrostatics is also found to play a significant role in deciding velocity gradients at the interface. High frequency of the applied electric field is observed to generate an approximately static velocity profile away from the Electric Double Layer (EDL). PMID:26773725

  13. System Frequency as Information Carrier in AC Power Systems

    Douglass, Philip James; Heussen, Kai; You, Shi;

    2015-01-01

    -DER) using changes to frequency setpoint values of genera- tors. Signaling discrete system states by generating off-nominal system frequency values can be used as a novel narrowband unidirectional broadcast communications channel. This paper describes two protocols for utilizing off-nominal frequencies...... to carry information: First, a protocol for dispatching blocks of FS- DER that is suitable for systems restricted to relatively slow rates of change of frequency (ROCOF). Second, for systems that allow higher ROCOF values, the feasibility of using power generation resources as a power line communication...... is shown with laboratory tests of a 20 kVA inverter. The inverter was found to have a maximum ROCOF of 2.2 Hz/s, sufficient to enable its use as a power line communication transmitter...

  14. An NPV and AC Analysis of a Stochastic Inventory System with Joint Manufacturing and Remanufacturing

    E.A. van der Laan (Erwin)

    2000-01-01

    textabstractWhile the net present value (NPV) approach is widely accepted as the right framework for studying production and inventory control systems, average cost (AC) models are more widely used. For the well known EOQ model it can be veri_ed that (under certain conditions) the AC approach gives

  15. A Simulator Study of Recovery of HVDC Links Following AC System Faults

    J. Senthil; Padiyar, KR; Sachchidanand, *

    1990-01-01

    This paper presents the simulator study of a two-terminal HVDC system. The various AC system faults to which the study system is subjected are a) remote-three-phase ground fault, b)single-phase-ground fault and three phase ground faults. These faults are applied both at the rectifier and inverter ends. The results of the simulator study are presented to demonstrate the controller performance in the recovery of HVDC link following AC system faults.

  16. Research on closed-loop simulation system for digital AC servo system

    2009-01-01

    An intelligent and efficient closed-loop simulation system without any hardware is proposed for AC servo system.According to the characteristics of AC servo system and its control processor,the code executing platform combined with the reverse Polish notation algorithm is developed.To gain the accurate simulation results,the discrete motor model and IPM model are built to deal with the dead-time.Based on the simulation system,parameter identification can be implemented and control parameters can be optimized by using the exhaust algorithm.The parameters obtained by the simulation system were successfully applied to an experimental system,and the favorable control performance was achieved.

  17. Voltage Swell Mitigation Using Flexible AC Transmission Systems Based on Evolutionary Computing Methods

    Marwa Shahin; Ebtisam Saied; M.A. Moustafa Hassan; Fahmy Bendary

    2014-01-01

    The main subject of these paper deals with enhancing the steady-state and dynamics performance of the power grids by using new idea namely Advanced Flexible AC Transmission Systems based on Evolutionary Computing Methods. Control of the electric power system can be achieved by using the new trends as Particle Swarm Optimization applied to this subject to enhance the characteristics of controller performance. This paper studies and analyzes Advanced Flexible AC Transmission System to mitigate ...

  18. Frequency support among asynchronous AC systems through VSCs emulating power plants

    Papangelis, Lampros; Guillaud, Xavier; Van Cutsem, Thierry

    2015-01-01

    This paper proposes a new control scheme for the Voltage Source Converters (VSCs) of a High Voltage Direct Current (HVDC) grid connecting asynchronous AC systems, so that the latter can mutually support their frequencies after a disturbance. The scheme involves no communication between VSCs. It is activated upon detection of a significant frequency deviation, with the possibility to limit the support requested from other AC systems. It relies on an integral control enforcing the frequency dro...

  19. A New Simulator for HVdc/ac Systems-Part I

    ZANGENEH, B. Zohouri; SHOULAIE, A.

    2003-01-01

    A simulator with optimal step time (SOST) has been designed to investigate Large HVdc/ac systems. The adequacy and robustness of the simulator will be demonstrated by showing some important applications relevant to operation, operational planning and medium-term planing. Some of the features of our SOST simulator are optimal step time algorithm, interpolation, chatter removal, MATLAB interface, unlimited size of ac system, and Farsi command that help model complex power electronic ci...

  20. Risk Based Assessment of Subsynchronous Resonance in AC/DC Systems

    Adrees, Atia

    2014-01-01

    Risk Based Assessment of Subsynchronous Resonance in compensated AC/DC systemMrs Atia Adrees, The University of Manchester, April 2014This thesis investigates the phenomenon of subsynchronous resonance (SSR) in meshed series compensated AC/DC systems in the presence of operational uncertainties. The main contribution of this research is the novel application of risk assessment methods to SSR studies.In terms of network topology, future electric power transmission networks alongside the curren...

  1. Marketing information system online design for craftsmen small medium enterprises (case study: craftsmen ac)

    Fitriana, Rina; Kurniawan, Wawan; Barlianto, Anung; Adriansyah Putra, Rizki

    2016-02-01

    AC is small and medium enterprises which is engaged in the field of crafts. This SME (Small Medium Enterprise) didn't have an integrated information system for managing sales. This research aims to design a marketing Information system online as applications that built as web base. The integrated system is made to manage sales and expand its market share. This study uses a structured analysis and design in its approach to build systems and also implemented a marketing framework of STP (Segmentation, Targeting, Positioning) and 4P (Price, Product, Place, Promotion) to obtain market analysis. The main market target customer craftsmen AC is women aged 13 years to 35 years. The products produced by AC are shoes, brooch, that are typical of the archipelago. The prices is range from Rp. 2000 until Rp. 400.000. Marketing information system online can be used as a sales transaction document, promoting the goods, and for customer booking products.

  2. Development of an electric power conversion system using a high frequency AC insulating link system. Koshuha AC zetsuen link hoshiki wo mochiita denryoku henkan system no kaihatsu

    1991-05-10

    An electric power convertion system incorporating a cycloconverter type high frequency AC insulating link system of which object was the dispersed power sources of 5KVA class was experimentally developed to evaluate the properties of the developed equipment. The system was composed of a cycloconverter which converted the frequency from 20kHz to 60Hz directly by converting DC to high frequency AC at the 20kHz high frequency inverter, and then by connecting to a high frequency transformer which insulated between the inputting side and the outputting circuit. The multi-functional hybrid IC technology where semiconductor elements, driving circuits, current detecting elements and overcurrent cut-off circuits were incorporated into a module, was introduced. As a result, the size of the high frequency transformer became one-tenth or less the size of transformer using commercial frequency and the weight reduced to about one-twentyfifth. When the commutation of high frequency power source and the forced gate commutation were used jointly, the efficiency was improved by 10 percentage at the 100 percentage load, compared with the case using only the forced gate commutation and the efficiency of mounted equipment was 90 percentage. 3 figs.

  3. Study of the DEF Feedback Control System in AC Operation of Superconducting Tokamak

    WANG Hua; LUO Jiarong; YUAN Qiping; XU Congdong

    2007-01-01

    AC operation with multiple full cycles has been successfully performed on the superconducting tokamak HT-7. In the experiment, it was discovered that the saturation of the transformer magnetic flux with DEF, a signal name, was one of key aspects that affected the AC operation. The conditions of DEF were examined through the DEF feedback control system. By controlling the working patterns of the subsystems, namely the poloidal field control system and density control system, it was guaranteed that DEF would remain in the non-saturated status.

  4. Study of the DEF Feedback Control System in AC Operation of Superconducting Tokamak

    Wang, Hua; Luo, Jiarong; Yuan, Qiping; Xu, Congdong

    2007-02-01

    AC operation with multiple full cycles has been successfully performed on the superconducting tokamak HT-7. In the experiment, it was discovered that the saturation of the transformer magnetic flux with DEF, a signal name, was one of key aspects that affected the AC operation. The conditions of DEF were examined through the DEF feedback control system. By controlling the working patterns of the subsystems, namely the poloidal field control system and density control system, it was guaranteed that DEF would remain in the non-saturated status.

  5. Harmonic detection an AC excited generation system based on in-phase correlation filtering

    2002-01-01

    The paper reports results of investigation on the harmonic detection technique of a complicated power supply system such as an AC excited generation system, which has a variable fundamental frequency and low order harmonics with rich sub-harmonics whose frequencies are lower than the fundamental one. The in-phase correlation filtering technique, based on the frequency shifting principle, is proposed in this paper. Theoretical analysis and experimental results validate the effectiveness of this technique for the harmonic detections of AC excited generation systems.

  6. Design issues of the TF AC/DC converter for the ITER coil power supply system

    The ITER Toroidal Field (TF) coil system is composed of 18 series-connected superconductor coils (L=17.5 Henry), related protection circuits, and an AC/DC converter. The converter for the TF coil system is a 12-pulse and 2-quadrant converter with the two thyristor bridges connected in parallel through the inter-phase reactor. The rated current of the converter is 68 kA, and no-load output voltage is 900 V when 66 kV AC input is used. Because ITER is a pulse system that uses huge power during the pulse, there are additional critical issues in designing the AC/DC converters. In this study the following issues in designing the TF AC/DC converter are discussed to improve the characteristics of the TF coil system; - Fault current issues related with AC input voltage and operational scenario. - Junction temperatures during the faults and the thyristor numbers per an arm. - Efficient and reliable bypass method including resuming. - Protection sequence for the fault conditions. - Reactive power reduction method. - Estimation of the optimum inductance of the DC Reactor (DCR)

  7. Combined operation of AC and DC distribution system with distributed generation units

    This paper presents a DC distribution system which has been supplied by external AC systems as well as local DG units in order to demonstrate an overall solution to power quality issue. In this paper, the proposed operation method is demonstrated by simulation of power transfer between external AC systems, DG units, AC and DC loads. The power flow control in DC distribution system has been achieved by network converters and DG converters. Also, the mathematical model of the network, DG and load converters are obtained by using the average technique, which allows converter systems accurately simulated and control strategies for this converters is achieved. A suitable control strategy for network converters has been proposed that involves DC voltage droop regulator and novel instantaneous power regulation scheme. Also, a novel control technique has been proposed for DG converters. In this paper, a novel control system based on stationary and synchronously rotating reference frame has been proposed for load converters for supplying AC loads connected to the DC bus by balanced voltages. The several case studies have been studied based on proposed methods. The simulation results show that DC distribution systems including DG units can improve the power quality at the point of common coupling (PCC) in the power distribution system or industrial power system. (authors)

  8. Electromechanical systems with transient high power response operating from a resonant ac link

    Burrows, Linda M.; Hansen, Irving G.

    1992-01-01

    The combination of an inherently robust asynchronous (induction) electrical machine with the rapid control of energy provided by a high frequency resonant ac link enables the efficient management of higher power levels with greater versatility. This could have a variety of applications from launch vehicles to all-electric automobiles. These types of systems utilize a machine which is operated by independent control of both the voltage and frequency. This is made possible by using an indirect field-oriented control method which allows instantaneous torque control all four operating quadrants. Incorporating the ac link allows the converter in these systems to switch at the zero crossing of every half cycle of the ac waveform. This zero loss switching of the link allows rapid energy variations to be achieved without the usual frequency proportional switching loss. Several field-oriented control systems were developed under contract to NASA.

  9. Design study of an AC power supply system in JT-60SA

    In the initial research phase of JT-60SA, which is the International Thermonuclear Experimental Reactor (ITER) satellite Tokamak with superconducting toroidal and poloidal magnetic field coils, the plasma heating operation of 30 MW-60 s or 20 MW-100 s is planned for 5.5 MA single null divertor plasmas. To achieve this operation, AC power source of the medium voltage of 18 kV and ∼7 GJ has to be provided in total to the poloidal field coil power supplies and additional heating devices such as neutral beam injection (NBI) and electron cyclotron radio frequency (ECRF). In this paper, the proposed AC power supply system in JT-60SA was estimated from the view point of available power, and harmonic currents based on the standard plasma operation scenario during the initial research phase. This AC power supply system consists of the reused JT-60 power supply facilities including motor generators with flywheel, AC breakers, harmonic filters, etc., to make it cost effective. In addition, the conceptual design of the upgraded AC power supply system for the ultimate heating power of 41 MW-100 s in the extended research phase is also described.

  10. Electromechanical systems with transient high power response operating from a resonant AC link

    Burrows, Linda M.; Hansen, Irving G.

    1992-01-01

    The combination of an inherently robust asynchronous (induction) electrical machine with the rapid control of energy provided by a high frequency resonant AC link enables the efficient management of higher power levels with greater versatility. This could have a variety of applications from launch vehicles to all-electric automobiles. These types of systems utilize a machine which is operated by independent control of both the voltage and frequency. This is made possible by using an indirect field-oriented control method which allows instantaneous torque control in all four operating quadrants. Incorporating the AC link allows the converter in these systems to switch at the zero crossing of every half cycle of the AC waveform. This zero loss switching of the link allows rapid energy variations to be achieved without the usual frequency proportional switching loss. Several field-oriented control systems were developed by LeRC and General Dynamics Space Systems Division under contract to NASA. A description of a single motor, electromechanical actuation system is presented. Then, focus is on a conceptual design for an AC electric vehicle. This design incorporates an induction motor/generator together with a flywheel for peak energy storage. System operation and implications along with the associated circuitry are addressed. Such a system would greatly improve all-electric vehicle ranges over the Federal Urban Driving Cycle (FUD).

  11. Modelling and control of hybrid renewable energy system connected to AC grid

    Sami Younsi

    2011-12-01

    Full Text Available This paper discusses the development of new control and supervision method for the optimum operation of hybrid renewable energy system (HRES connected to AC grid. The hybrid system consists of wind generator (WG, diesel generator (DG, and flywheel energy storage system (FESS. These subsystems are based on permanent magnet synchronous machines (PMSM which are controlled by sliding mode control. A supervisor control is designed to determine the energy transfer type of flywheel energy storage system (charging / discharging / no transfer energy, to take decision on diesel generators ON/OFF status, and to determine the reference powers for these two subsystems. The supervisor inputs are the power requested by AC grid, the power generated by wind generator, and the energy stored in flywheel. The objectives of the control and supervision for hybrid renewable energy system are to satisfy the power requested by AC grid, to manage the energy transfer between hybrid system and AC grid, to optimize the use of wind energy, and to reduce fuel of diesel generator. The system is simulated with Matlab – Simulink software and it gave good results.

  12. Methods, systems and apparatus for controlling operation of two alternating current (AC) machines

    Gallegos-Lopez, Gabriel; Nagashima, James M.; Perisic, Milun; Hiti, Silva

    2012-06-05

    A system is provided for controlling two alternating current (AC) machines via a five-phase PWM inverter module. The system comprises a first control loop, a second control loop, and a current command adjustment module. The current command adjustment module operates in conjunction with the first control loop and the second control loop to continuously adjust current command signals that control the first AC machine and the second AC machine such that they share the input voltage available to them without compromising the target mechanical output power of either machine. This way, even when the phase voltage available to either one of the machines decreases, that machine outputs its target mechanical output power.

  13. Study of Power Flow Algorithm of AC/DC Distribution System including VSC-MTDC

    Haifeng Liang

    2015-08-01

    Full Text Available In recent years, distributed generation and a large number of sensitive AC and DC loads have been connected to distribution networks, which introduce a series of challenges to distribution network operators (DNOs. In addition, the advantages of DC distribution networks, such as the energy conservation and emission reduction, mean that the voltage source converter based multi-terminal direct current (VSC-MTDC for AC/DC distribution systems demonstrates a great potential, hence drawing growing research interest. In this paper, considering losses of the reactor, the filter and the converter, a mathematical model of VSC-HVDC for the load flow analysis is derived. An AC/DC distribution network architecture has been built, based on which the differences in modified equations of the VSC-MTDC-based network under different control modes are analyzed. In addition, corresponding interface functions under five control modes are provided, and a back/forward iterative algorithm which is applied to power flow calculation of the AC/DC distribution system including VSC-MTDC is proposed. Finally, by calculating the power flow of the modified IEEE14 AC/DC distribution network, the efficiency and validity of the model and algorithm are evaluated. With various distributed generations connected to the network at appropriate locations, power flow results show that network losses and utilization of transmission networks are effectively reduced.

  14. AC Versus DC Link Comparison Based on Power Flow Analysis of a Multimachine Power System

    Mohammed Abdeljalil DJEHAF

    2014-02-01

    Full Text Available Deregulation and privatization is posing new challenges on high voltage transmission and on distributions systems as well. An increasingly liberalized market will encourage trading opportunities to be identified and developed. High voltage power electronics, such as HVDC (High Voltage Direct Current and FACTS (Flexible AC Transmission Systems provide the necessary features to avoid technical problems in heavily loaded power systems; HVDC offers most advantages: it can be used for system interconnection and for control of power flow as well. The major benefit of HVDC is its incorporated ability for fault-current blocking, which is not possible with synchronous AC links. In addition, HVDC can effectively support the surrounding AC systems in case of transient fault conditions and it serves as firewall against cascading disturbances. This paper presents a comparison between HVDC link and an HVAC link in a 29 Bus multimachine system, based on load flow analysis using Newton-Raphson method for the AC link case, and sequential method for the HVDC link case.

  15. Theoretical and experimental investigation into anti-idling A/C system for trucks

    Highlights: • A mathematical model is developed and verified using a built test-bed. • Thermal and performance characteristics of an anti-idling truck A/C system are investigated. • It is shown that variable speed fans have significant effects on the COP in different conditions. • A point of optimum COP can be found by changing the fans speed for any operating condition. • Anti-idling A/C systems equipped to variable speed control can significantly save environment. - Abstract: In this study, a recently developed truck anti-idling air conditioning (A/C) system is investigated. A mathematical model is developed to simulate the thermodynamic and heat transfer characteristics of the A/C system and calculate the coefficient of performance (COP). Utilizing environmental chambers and a number of measuring equipment, an experimental setup is built to verify the accuracy of the mathematical model and to perform a comprehensive study on the performance of the system for a wide range of operating conditions. A good agreement between the simulation and the experimental data, with a maximum discrepancy of 10.6%, is achieved. The results show a range of 0.5–1.7 for the system COP under a variety of operating condition. The parametric study shows that for any cooling demand, ambient and indoor air temperatures, there is a point of optimum COP that can be achieved by adjusting the condenser and evaporator fans speed

  16. Model of Bi-directional Flyback Converter for Hybrid AC/DC Distribution System

    Riku Pasonen

    2013-01-01

    In this article, a simulation model and concept of two switch bi-directional isolated DC/DC converter is presented. Converter is based on flyback converter type. Also control method for voltage regulation with bi-directional power transfer is presented. Target application of the proposed converter was selected to be a hybrid AC/DC distribution system concept of which was briefly described. The requirement of galvanic isolation in the hybrid AC/DC concept comes from use of shared neutral wire;...

  17. Internal Heating of an IGBT module in a System With a Regenerative AC Drive

    Mabano, Michel

    2016-01-01

    The purpose of this thesis was to understand the internal heating of an IGBT module inside an AC drive in a system with a regenerative unit to it. During the implementation of the lab, various approaches were taken in an effort to collect measurements appropriate to the topic of investigation. The IGBT junction temperature was recorded over a sustained period of time at various speed of the induction motor. The braking torque applied through a second AC drive was varied in order to study...

  18. Model of Bi-directional Flyback Converter for Hybrid AC/DC Distribution System

    Riku Pasonen

    2013-12-01

    Full Text Available In this article, a simulation model and concept of two switch bi-directional isolated DC/DC converter is presented. Converter is based on flyback converter type. Also control method for voltage regulation with bi-directional power transfer is presented. Target application of the proposed converter was selected to be a hybrid AC/DC distribution system concept of which was briefly described. The requirement of galvanic isolation in the hybrid AC/DC concept comes from use of shared neutral wire; DC current runs with unbalanced part of AC current in neutral wire. Without galvanic isolation grounded neutral would cause short circuit if DC/DC converter is connected to three phase rectifier or inverter. Simulation was carried out with PSCAD electromagnetic transient simulator.

  19. Development of New Type Gap Arrester for Earth Fault Protection in AC Feeding System

    Ajiki, Kohji; Morimoto, Hiroaki; Hisamizu, Yasuzi; Kinoshita, Nobuo; Takai, Wataru; Sato, Ryogo

    A gap arrester is being used for ground fault protection in AC Feeding System. However there are faults in which a conventional gap arrester burns down in a normal state of circuit. We investigated the cause of the fault in which a gap arrester burns. Then, it was found out that the cause of the fault was the discharge of AC current from the surge voltage. Therefore, we developed a new type gap arrester which does not burn down. The new type gap arrester is composed of a discharge tube and a zinc oxide element which are connected in series. Unnecessary AC current discharge is prevented by this structure. The new type gap arrester is actually used at the railroad track.

  20. Modeling and Analysis of Harmonic Stability in an AC Power-Electronics-Based Power System

    Wang, Xiongfei; Blaabjerg, Frede; Wu, Weimin

    2014-01-01

    This paper addresses the harmonic stability caused by the interactions among the wideband control of power converters and passive components in an AC power-electronicsbased power system. The impedance-based analytical approach is employed and expanded to a meshed and balanced threephase network w...

  1. A Series-LC-Filtered Active Damper for AC Power Electronics Based Power Systems

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

    2015-01-01

    This paper proposes an active damper with a series LC-filter for suppressing resonances in an ac power electronics based power system. The added filter capacitor helps to lower the voltage stress of the converter to be used for implementing the damper. Unlike active filters for the compensation of...

  2. Autonomous Active Power Control for Islanded AC Microgrids with Photovoltaic Generation and Energy Storage System

    Wu, Dan; Tang, Fen; Dragicevic, Tomislav; Vasquez, Juan Carlos; Guerrero, Josep M.

    2014-01-01

    In an islanded AC microgrid with distributed energy storage system (ESS), photovoltaic (PV) generation and loads, a coordinated active power regulation is required to ensure efficient utilization of renewable energy, while keeping the ESS from overcharge and over discharge conditions. In this pap...

  3. Flow diagram of the longitudinal and Hall conductivities in ac regime in the disordered graphene quantum Hall system

    We numerically study the behavior of σxy(ω) and σxx (ω) for graphene QHE system in the ac (frequency ω) domain. We interpret these conductivities with the dynamical scaling analysis. We also discuss the temperature flow of σxy(ω) — σxx(ω) diagram for graphene QHE system in the ac region.

  4. Digital Signal Processor System for AC Power Drivers

    Ovidiu Neamtu

    2009-10-01

    Full Text Available DSP (Digital Signal Processor is the bestsolution for motor control systems to make possible thedevelopment of advanced motor drive systems. The motorcontrol processor calculates the required motor windingvoltage magnitude and frequency to operate the motor atthe desired speed. A PWM (Pulse Width Modulationcircuit controls the on and off duty cycle of the powerinverter switches to vary the magnitude of the motorvoltages.

  5. Control Structures for VSC-based FACTS Devices under Normal and Faulted AC-systems

    Babaei, Saman

    This thesis is concerned with improving the Flexible AC Transmission Systems (FACTS) devices performance under the normal and fault AC-system conditions by proposing new control structures and also converter topologies. The combination of the increasing electricity demand and restrictions in expanding the power system infrastructures has urged the utility owners to deploy the utility-scaled power electronics in the power system. Basically, FACTS is referred to the application of the power electronics in the power systems. Voltage Source Converter (VSC) is the preferred building block of the FACTS devices and many other utility-scale power electronics applications. Despite of advances in the semiconductor technology and ultra-fast microprocessor based controllers, there are still many issues to address and room to improve[25]. An attempt is made in this thesis to address these important issues of the VSC-based FACTS devices and provide solutions to improve them.

  6. Optimization Control of Bidirectional Cascaded DC-AC Converter Systems

    Tian, Yanjun

    reliability in bidirectional cascaded converter. This research work analyses the control strategies based on the topology of dual active bridges converter cascaded with a three phase inverter. It firstly proposed a dc link voltage and active power coordinative control method for this cascaded topology, and it...... can reduce dc link voltage fluctuations, enhancing the dc link voltage reliability in case of one sub converter failure. Then the bidirectional power flow effect is analyzed, and an important guide line is proposed for the design of the two stage cascaded converter system. Towards the different...... reduce the dc link voltage control system type number, which is capable to improve system stability. Afterwards, this dissertation comes up with the concept of front to end impedance control method for the two stage cascaded converter, and it can greatly improve the system stability. At last the thesis...

  7. Direct AC–AC grid interface converter for ocean wave energy system

    Highlights: • Novel power grid interface converter for ocean wave energy system. • Unlike conventional approach, generator output is directly converted into fixed frequency AC for synchronous connection. • High conversion efficient and power quality could be achieved. - Abstract: Ocean wave energy is very promising. However, existing systems are using rectifying circuits to convert variable voltage and variable frequency output of electric generator into DC voltage and then use grid-tied inverter to connect to the power grid. Such arrangement will not only reduce the overall efficient but also increase the cost of the system. A direct AC–AC converter is a desirable solution. In this paper, a six-switch AC–AC converter has been proposed as a single phase grid-connected interface. New switching scheme has been derived for the converter such that the virtual input AC–DC conversion and the output DC–AC conversion can be decoupled. State-space averaging model and pulse width modulation scheme have been derived for the converter. As the input and the output operations can be decoupled, two independent controllers have been designed to handle the input AC–DC regulation and the output DC–AC regulation. The proposed scheme demands for two separate duty ratios and novel switching scheme has been derived to realize the combined duty ratios in one switching cycle. Power regulation, harmonics elimination and power factor correction control algorithms have also been derived for the converter when it is connected to the supply grid. Experimental results of a small scale model are included to demonstrate the effectiveness of the proposed switching and control schemes

  8. System co-optimization in wireless receiver design with TrACS

    Ramesh, Chithrupa; Rusu, Ana; Ismail, Mohammed; Skoglund, Mikael

    2008-01-01

    System co-optimization of the analog receiver front end circuit and the digital baseband processing could enable receiver designs with lower power budgets, as the signal processing in the digital receiver is asymmetric across circuit topologies. This paper presents a simulation tool that could assist with such co-optimized designs. TrACS (Transceiver Architecture and Channel Simulator) is an RF/DSP co-simulator, capable of providing an application-specific system-level perspective to receiver...

  9. Harmonic Analysis of AC-DC Topologies and their Impacts on Power Systems

    Mukhtiar Ahmed Mahar; Muhammad Aslam Uqaili; Abdul Sattar Larik

    2011-01-01

    Power Electronic Converters are commonly used in different applications because of high efficiency and low cost. Due to latest advancement in semiconductor devices it is difficult to draw the boundaries for applications of power electronic topologies. These topologies are variable structure systems and generate harmonics during the operation which will affect the power quality when are connected to system network. Rectifier is a big family of converters and used when ac-dc conv...

  10. Power Electronics for Mitigation of Voltage Sags and Improved Control of AC Power Systems

    Magalhães de Oliveira, Marcio

    2000-01-01

    The thesis deals with the application of compensators andswitches based on power electronics in AC transmission anddistribution systems. The objective of the studieddevices/equipment is the power flow and voltage control intransmission systems and the mitigation of voltage sags andmomentary interruptions to critical loads in distributionsystems. For validating the power electronics based devices/equipmentdescribed in the thesis, scaled models at a real-time simulatorhave been built. Simulatio...

  11. A reduction of proof complexity to computational complexity for $AC^0[p]$ Frege systems

    Krajicek, Jan

    2013-01-01

    We give a general reduction of lengths-of-proofs lower bounds for constant depth Frege systems in DeMorgan language augmented by a connective counting modulo a prime $p$ (the so called $AC^0[p]$ Frege systems) to computational complexity lower bounds for search tasks involving search trees branching upon values of maps on the vector space of low degree polynomials over the finite filed with $p$ elements.

  12. Influence of the iodide/iodine redox system on the self-discharge of AC/AC electrochemical capacitors in salt aqueous electrolyte

    Qamar Abbas

    2015-12-01

    Full Text Available Self-discharge (SD of AC/AC (AC=activated carbon electrochemical capacitors in aqueous solutions of lithium sulfate (Li2SO4 and lithium sulfate+iodide salts (Li2SO4+KI or Li2SO4+LiI was investigated at 24 °C and −40 °C after cell potential hold at values from 1 V to 1.6 V. At 24 °C, the cells exhibit lower SD in Li2SO4+KI than in Li2SO4, owing to the redox activity of the 2I−/I2 system which drives the positive AC electrode to operate in narrow potential range and display lower potential drop than in Li2SO4. At −40°C, the capacitors exhibit comparable and reduced SD both in Li2SO4+LiI and Li2SO4, whatever the holding cell potential. Three-electrode cell experiments demonstrate that, at −40 °C, hydrogen chemisorption is thermodynamically unfavored under negative polarization, while the activity of the 2I−/I2 redox system under positive polarization is only slightly reduced. As a consequence, the AC/AC cells in Li2SO4 exhibit a typical electrical double-layer performance at −40°C, whereas they still behave as hybrid ones in Li2SO4+LiI, with twice higher capacitance than in Li2SO4. The (Ui-Ut vs t1/2 plots demonstrate that SD is essentially controlled by diffusion at −40°C, suggesting that it originates from bulkier hydrated ions. Overall, in the investigated temperature range, the AC/AC capacitors in Li2SO4+LiI demonstrate low self-discharge and high capacitance, while being able to operate up to 1.6 V.

  13. Enhancing the Capacity of the AC Distribution System Using DC Interlinks - A Step Towards Future DC Grid

    Chaudhary, Sanjay; Guerrero, Josep M.; Teodorescu, Remus

    2015-01-01

    , the dc grid interconnection also allows the introduction of a common storage system which can be shared by the connected ac feeders, and the dc grid connection to other renewable energy resources. The increased power handling capacity and improved voltage profile of the ac distribution feeder using...

  14. An evaluation of the Panasonic model UD513AC-1 Thermoluminescence Dosimetry system

    An evaluation of the Panasonic UD513AC-1 Thermoluminescence Dosimetry system was performed to determine the system's capabilities as a general purpose thermoluminescence dosimeter measuring device. The tests that were performed included a critique of the user's manual, delimitation of the operating parameters, the quality of construction, and an evaluation of the features that were unique to this system. The UD513AC-1 was found to be an adequate measuring device for most dosimetric applications. It was not well suited for experimental work with thermoluminescence materials due to a low sensitivity displayed by the photomultiplier tube to commonly used materials. The system was well constructed and did not suffer hardware failure during this research. Major attributes of the UD513AC-1 were automatic data storage, highly reproducible heating ramps, an excellent infrared light filter and a unique feature to a single phosphor unit, a dose determination function. Negative aspects of the system included a limited data manipulation capability within the controlling program, a poorly written user's manual, inadequate sensitivity on the part of the photomultiplier tube, and insufficient capability to adjust the hot N2 gas flow to desired levels

  15. Mathematical analysis of parameter maintenance in precision technological V and AC systems (rus

    Sotnikov A.G.

    2011-08-01

    Full Text Available Various industrial processes usually take place in the air and they require different parameters of air quality and accuracy of its maintenance.In present there are no rigorous analytical methods for reliable determination the actual accuracy of maintenance of air quality parameters on condition that they change orderly or stochastically. The harmonic analysis of exponents of periodical increase and decrease of parameters is proposed. It can be used for the estimation of fluctuations and precision of maintenance of various air quality parameters, first of all, in precision technological V and AC systems.Suggested method of temperature calculation under changing periodical heat load at the premises is illustrated by the example of high-precision V and AC system operating the area of grinding and test of optical devices.

  16. ABB ACS6000传动系统在热轧线的应用%Application of ABB ACS6000 Driver System in Hot-rolling Line

    孙坚; 王君艳

    2012-01-01

    宝钢股份特钢事业部热轧厂粗轧机同步电机主传动上应用了ACS6000中压变频传动系统,采用电力电子元件IGCT作为其功率元件.详细介绍了该变频系统的硬件结构、软件组成以及技术特点.%In the hot-rolling workshop of Baosteel Special branch, ABB ACS6000 medium voltage variable speed drive system is used for rough-rolling mill synchronous motor. This system is equipped with so called integrated gate commutated thyristors (ICCT) as its power element. Detailed described the hardware and software configuration, technical characteristic of the drive system.

  17. An active damper for stabilizing power-electronics-based AC systems

    Wang, Xiongfei; Blaabjerg, Frede; Liserre, Marco;

    2014-01-01

    The interactions among the parallel grid-connected converters coupled through the grid impedance tend to result in stability and power quality problems. To address them, this paper proposes an active damper based on a high bandwidth power electronics converter. The general idea behind this proposal...... experimental tests on a three-converter-based setup are carried out. The results show that the active damper can become a promising way to stabilize the power-electronics-based ac power systems....

  18. Comparison of Two Autonomous AC-DC Converters for Piezoelectric Energy Scavenging Systems

    Dallago, Enrico; Miatton, Daniele; Venchi, Giuseppe; Bottarel, Valeria; Frattini, Giovanni; Ricotti, Giulio; Schipani, Monica

    2010-01-01

    International audience Piezoelectric Energy Scavenging Systems (PESS) are used to convert the energy of mechanical vibrations into electrical energy exploiting the piezoelectric effect. Their output is a voltage which strongly varies in time; to obtain a suitable supply source an AC-DC conversion of the output voltage of these transducers is needed. Since the output power level of the energy transducer can be very low, the conversion should be as efficient as possible. The paper describes ...

  19. DC and AC Josephson Effect in a Superconductor-Luttinger Liquid-Superconductor System

    Fazio, Rosario; Hekking, F. W. J.; Odintsov, A.A.; RevTex, 11 pages; figures, 9

    1995-01-01

    We calculate both the DC and the AC Josephson current through a one-dimensional system of interacting electrons, connected to two superconductors by tunnel junctions. We treat the (repulsive) Coulomb interaction in the framework of the one-channel, spin-$1/2$ Luttinger model. The Josephson current is obtained for two geometries of experimental relevance: a quantum wire and a ring. At zero temperature, the critical current is found to decay algebraically with increasing distance $d$ between th...

  20. MODES OF OPERATION OF THE SYSTEM OF TRACTION POWER AC USING REACTIVE POWER COMPENSATION DEVICES

    Domanskyi, I. V.

    2015-01-01

    The paper presents a systematic analysis of existing methods of reactive power compensation. The study of operating modes of the systems external and traction power supply is carried out. The methodology for selecting promising compensation schemes and energy-saving in the traction networks AC electrified railway lines is offered. The comparative evaluation of prospective controlled compensation devices shows that use of seamlessly adjustable devices with unregulated condensing the battery an...

  1. Modeling and Analysis of Harmonic Stability in an AC Power-Electronics-Based Power System

    Wang, Xiongfei; Blaabjerg, Frede; Wu, Weimin

    2014-01-01

    This paper addresses the harmonic stability caused by the interactions among the wideband control of power converters and passive components in an AC power-electronicsbased power system. The impedance-based analytical approach is employed and expanded to a meshed and balanced threephase network which is dominated by multiple current- and voltage- controlled inverters with LCL- and LC-filters. A method of deriving the impedance ratios for different inverters is proposed by means of the nodal a...

  2. Scalable Heuristics for Planning, Placement and Sizing of Flexible AC Transmission System Devices

    Frolov, Vladmir [Skolkovo Institute of Science and Technology, Skolkovo (Russia); Backhaus, Scott N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chertkov, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-02

    Aiming to relieve transmission grid congestion and improve or extend feasibility domain of the operations, we build optimization heuristics, generalizing standard AC Optimal Power Flow (OPF), for placement and sizing of Flexible Alternating Current Transmission System (FACTS) devices of the Series Compensation (SC) and Static VAR Compensation (SVC) type. One use of these devices is in resolving the case when the AC OPF solution does not exist because of congestion. Another application is developing a long-term investment strategy for placement and sizing of the SC and SVC devices to reduce operational cost and improve power system operation. SC and SVC devices are represented by modification of the transmission line inductances and reactive power nodal corrections respectively. We find one placement and sizing of FACTs devices for multiple scenarios and optimal settings for each scenario simultaneously. Our solution of the nonlinear and nonconvex generalized AC-OPF consists of building a convergent sequence of convex optimizations containing only linear constraints and shows good computational scaling to larger systems. The approach is illustrated on single- and multi-scenario examples of the Matpower case-30 model.

  3. Very low noise AC/DC power supply systems for large detector arrays

    Arnaboldi, C.; Baù, A.; Carniti, P.; Cassina, L.; Giachero, A.; Gotti, C.; Maino, M.; Passerini, A.; Pessina, G.

    2015-12-01

    In this work, we present the first part of the power supply system for the CUORE and LUCIFER arrays of bolometric detectors. For CUORE, it consists of AC/DC commercial power supplies (0-60 V output) followed by custom DC/DC modules (48 V input, ±5 V to ±13.5 V outputs). Each module has 3 floating and independently configurable output voltages. In LUCIFER, the AC/DC + DC/DC stages are combined into a commercial medium-power AC/DC source. At the outputs of both setups, we introduced filters with the aim of lowering the noise and to protect the following stages from high voltage spikes that can be generated by the energy stored in the cables after the release of accidental short circuits. Output noise is very low, as required: in the 100 MHz bandwidth the RMS level is about 37 μVRMS (CUORE setup) and 90 μVRMS (LUCIFER setup) at a load of 7 A, with a negligible dependence on the load current. Even more importantly, high frequency switching disturbances are almost completely suppressed. The efficiency of both systems is above 85%. Both systems are completely programmable and monitored via CAN bus (optically coupled).

  4. Combination of AC Transmission Expansion Planning and Reactive Power Planning in the restructured power system

    Highlights: ► To overcome the disadvantages of DC model in Transmission Expansion Planning, AC model should be used. ► The Transmission Expansion Planning associated with Reactive Power Planning results in fewer new transmission lines. ► Electricity market concepts should be considered in Transmission Expansion Planning problem. ► Reliability aspects should be considered in Transmission Expansion Planning problem. ► Particle Swarm Optimization is a suitable optimization method to solve Transmission Expansion Planning problem. - Abstract: Transmission Expansion Planning (TEP) is an important issue in power system studies. It involves decisions on location and number of new transmission lines. Before deregulation of the power system, the goal of TEP problem was investment cost minimization. But in the restructured power system, nodal prices, congestion management, congestion surplus and so on, have been considered too. In this paper, an AC model of TEP problem (AC-TEP) associated with Reactive Power Planning (RPP) is presented. The goals of the proposed planning problem are to minimize investment cost and maximize social benefit at the same time. In the proposed planning problem, in order to improve the reliability of the system the Expected Energy Not Supplied (EENS) index of the system is limited by a constraint. For this purpose, Monte Carlo simulation method is used to determine the EENS. Particle Swarm Optimization (PSO) method is used to solve the proposed planning problem which is a nonlinear mixed integer optimization problem. Simulation results on Garver and RTS systems verify the effectiveness of the proposed planning problem for reduction of the total investment cost, EENS index and also increasing social welfare of the system.

  5. An overview of power electronics applications in fuel cell systems: DC and AC converters.

    Ali, M S; Kamarudin, S K; Masdar, M S; Mohamed, A

    2014-01-01

    Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter. PMID:25478581

  6. High power switch mode linear amplifiers for flexible ac transmission system

    Mwinyiwiwa, B.; Wolanski, Z.; Ooi, B.T. [McGill Univ., Montreal, Quebec (Canada). Dept. of Electrical Engineering

    1996-10-01

    The Pulse Width Modulation (PWM) technique has been proposed for the force-commutated Shunt and Series VAR Controllers and Unified Power Flow Controllers in Flexible AC Transmission Systems. The PWM converters can be operated as linear amplifiers of constant gain so that treasure trove of linear control system theory can be brought to bear more easily when applying feedback controls. For example, pole-placement and active filtering have been successfully applied in laboratory models. This paper is written as a tutorial describing the stages of signal processing: modulation, amplification and demodulation, without reference to power electronics since the solid-state switches are modelled as ON-OFF switches.

  7. Fuzzy gain auto-tuning implementation for ac speed servo and mechanical motion load system

    In this paper, in order to suppress the mechanical resonance and anti- resonance in the DC brushless motor-based AC speed servo system with two-mass mechanical motion load, the load speed observer with load disturbance estimating function, which is suitable for the load speed feedback compensation, is proposed. The auto-tuning control implementation based on fuzzy reasoning with the observer- based load speed feedback compensation is compared with conventional PI compensation scheme. The experimental results prove considerable reduction in mechanical vibration and show improved response characteristics of mechanical motion load system. (author)

  8. Spin superconductivity and ac-Josephson effect in Graphene system under strong magnetic field

    Liu, Haiwen; Jiang, Hua; Sun, Qing-Feng; Xie, X. C.; Collaborative Innovation Center of Quantum Matter, Beijing, China Collaboration

    We study the spin superconductivity in Graphene system under strong magnetic field. From the microscopically Gor'kov method combined with the Aharonov-Casher effect, we derive the effective Landau-Ginzburg free energy and analyze the time evolution of order parameter, which is confirmed to be the off-diagonal long range order. Meanwhile, we compare the ground state of spin superconductivity to the canted-antiferromagnetic state, and demonstrate the equivalence between these two states. Moreover, we give out the pseudo-field flux quantization condition of spin supercurrent, and propose an experimental measurable ac-Josephson effect of spin superconductivity in this system.

  9. Comparison of the Accuracy and Speed of Transient Mobile A/C System Simulation Models: Preprint

    Kiss, T.; Lustbader, J.

    2014-03-01

    The operation of air conditioning (A/C) systems is a significant contributor to the total amount of fuel used by light- and heavy-duty vehicles. Therefore, continued improvement of the efficiency of these mobile A/C systems is important. Numerical simulation has been used to reduce the system development time and to improve the electronic controls, but numerical models that include highly detailed physics run slower than desired for carrying out vehicle-focused drive cycle-based system optimization. Therefore, faster models are needed even if some accuracy is sacrificed. In this study, a validated model with highly detailed physics, the 'Fully-Detailed' model, and two models with different levels of simplification, the 'Quasi-Transient' and the 'Mapped- Component' models, are compared. The Quasi-Transient model applies some simplifications compared to the Fully-Detailed model to allow faster model execution speeds. The Mapped-Component model is similar to the Quasi-Transient model except instead of detailed flow and heat transfer calculations in the heat exchangers, it uses lookup tables created with the Quasi-Transient model. All three models are set up to represent the same physical A/C system and the same electronic controls. Speed and results of the three model versions are compared for steady state and transient operation. Steady state simulated data are also compared to measured data. The results show that the Quasi-Transient and Mapped-Component models ran much faster than the Fully-Detailed model, on the order of 10- and 100-fold, respectively. They also adequately approach the results of the Fully-Detailed model for steady-state operation, and for drive cycle-based efficiency predictions

  10. Shot noise in nano-electronic systems under the perturbation of ac fields

    ZHAO Hong-kang

    2007-01-01

    Current noise exists in circuits and electronic devices generally, and it exhibits specific features as the system reaches nanometer size. The noise in the nano-system where external ac fields are applied plays an important role, since the properties of the fields and the nano-system together govern the resulting noise. In this paper, we present the derivation of shot noise by employing the nonequilibrium Green's function technique. The more general formulas for the current correlation and noise spectral density are given. The system is composed of a central nanosystem coupled to electrodes, and the obtained noise formulas are related to the Green's functions of detailed central regime and the terminals. As an example, we have performed the numerical calculation on a system with a toroidal carbon nanotube coupled to normal metal leads. The noise and Fano factor show intimate relation with the structure of the system and ac fields. The Aharonov-Bohm-like behaviors on the shot noise spectral density and Fano factor are observed to exhibit oscillation structures with period of quantum flux.

  11. Nonlinear control of voltage source converters in AC-DC power system.

    Dash, P K; Nayak, N

    2014-07-01

    This paper presents the design of a robust nonlinear controller for a parallel AC-DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC-DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations. PMID:24906895

  12. Optimized list-mode acquisition and data processing procedures for ACS2 based PET systems

    PET systems using the acquisition control system version 2 (ACS2), e.g. the ECAT Exact HR PET scanner series, offer a rather restricted list-mode functionality. For instance, typical transfers of acquisition data consume a considerable amount of time. This represents a severe obstacle to the utilization of potential advantages of list-mode acquisition. In our study, we have developed hardware and software solutions which do not only allow for the integration of list-mode into routine procedures, but also improve the overall runtime stability of the system. We show that our methods are able to speed up the transfer of the acquired data to the image reconstruction and processing workstations by a factor of up to 140. We discuss how this improvement allows for the integration of list-mode-based post-processing methods such as an event-driven movement correction into the data processing environment, and how list-mode is able to improve the overall flexibility of PET investigations in general. Furthermore, we show that our methods are also attractive for conventional histogram-mode acquisition, due to the improved stability of the ACS2 system. (orig.)

  13. Efficient harvesting of wet blue-green microalgal biomass by two-aminoclay [AC]-mixture systems.

    Ji, Hye-Min; Lee, Hyun Uk; Kim, Eui Jin; Seo, Soonjoo; Kim, Bohwa; Lee, Go-Woon; Oh, You-Kwan; Kim, Jun Yeong; Huh, Yun Suk; Song, Hyun A; Lee, Young-Chul

    2016-07-01

    Blue-green microalgal blooms have been caused concerns about environmental problems and human-health dangers. For removal of such cyanobacteria, many mechanical and chemical treatments have been trialled. Among various technologies, the flocculation-based harvesting (precipitation) method can be an alternative if the problem of the low yield of recovered biomass at low concentrations of cyanobacteria is solved. In the present study, it was utilized mixtures of magnesium aminoclay [MgAC] and cerium aminoclay [CeAC] with different particle sizes to harvest cyanobacteria feedstocks with ∼100% efficiency within 1h by ten-fold lower loading of ACs compared with single treatments of [MgAC] or [CeAC]. This success was owed to the compact networks of the different-sized-ACs mixture for efficient bridging between microalgal cells. In order to determine the usage potential of biomass harvested with AC, the mass was heat treated under the reduction condition. This system is expected to be profitably utilizable in adsorbents and catalysts. PMID:27023387

  14. Passive AC network supplying the integration of CCC-HVDC and VSC-HVDC systems

    BIDADFAR, Ali; Abedi, Mehrdad; KARRARI, Mehdi

    2014-01-01

    The integration of a capacitor-commutated converter (CCC) high-voltage direct current (HVDC) (CCC-HVDC) and voltage source converter (VSC) HVDC (VSC-HVDC) is proposed in this paper to supply entirely passive AC networks. The key point of this integration is the flat characteristic of the DC voltage of the CCC-HVDC, which provides the condition for the VSC to connect to the CCC DC link via a current regulator. The advantages of the proposed combined infeeding system are the requirement o...

  15. Coordinated Secondary Control for Balanced Discharge Rate of Energy Storage System in Islanded AC Microgrids

    Guan, Yajuan; Quintero, Juan Carlos Vasquez; Guerrero, Josep M.

    2016-01-01

    A coordinated secondary control approach based on an autonomous current-sharing control strategy for balancing the discharge rates of energy storage systems (ESSs) in islanded AC microgrids is proposed in this paper. The coordinated secondary controller can regulate the power outputs of distributed...... generation (DG) units according to their states-of-charge (SoCs) and ESS capacities by adjusting the virtual resistances of the paralleled voltage-controlled inverters. Compared with existing controllers, the proposed control strategy not only effectively prevents operation failure caused by overcurrent...

  16. Compensation methods applied in current control schemes for large AC drive systems

    Rus, D. C.; Preda, N. S.; Teodorescu, Remus; Imecs, M.

    The paper deals with modified PI current control structures for large AC drive systems which use surface mounted permanent magnet synchronous machines or squirrel-cage induction motors supplied with voltage source inverters. In order to reduce the power losses caused by high frequency switching of...... the semiconductor devices, various compensation methods are used and a modified structure for a PI current controller is proposed, to reduce the switching frequency of the inverter for the same operating frequency of the drive. Simulation, experimental development and test results are presented in...

  17. Voltage Stability Bifurcation Analysis for AC/DC Systems with VSC-HVDC

    Yanfang Wei

    2013-01-01

    Full Text Available A voltage stability bifurcation analysis approach for modeling AC/DC systems with VSC-HVDC is presented. The steady power model and control modes of VSC-HVDC are briefly presented firstly. Based on the steady model of VSC-HVDC, a new improved sequential iterative power flow algorithm is proposed. Then, by use of continuation power flow algorithm with the new sequential method, the voltage stability bifurcation of the system is discussed. The trace of the P-V curves and the computation of the saddle node bifurcation point of the system can be obtained. At last, the modified IEEE test systems are adopted to illustrate the effectiveness of the proposed method.

  18. System and component design and test of a 10 hp, 18,000 rpm AC dynamometer utilizing a high frequency AC voltage link, part 1

    Lipo, Thomas A.; Alan, Irfan

    1991-06-01

    Hard and soft switching test results conducted with one of the samples of first generation MOS-controlled thyristor (MCTs) and similar test results with several different samples of second generation MCT's are reported. A simple chopper circuit is used to investigate the basic switching characteristics of MCT under hard switching and various types of resonant circuits are used to determine soft switching characteristics of MCT under both zero voltage and zero current switching. Next, operation principles of a pulse density modulated converter (PDMC) for three phase (3F) to 3F two-step power conversion via parallel resonant high frequency (HF) AC link are reviewed. The details for the selection of power switches and other power components required for the construction of the power circuit for the second generation 3F to 3F converter system are discussed. The problems encountered in the first generation system are considered. Design and performance of the first generation 3F to 3F power converter system and field oriented induction moter drive based upon a 3 kVA, 20 kHz parallel resonant HF AC link are described. Low harmonic current at the input and output, unity power factor operation of input, and bidirectional flow capability of the system are shown via both computer and experimental results. The work completed on the construction and testing of the second generation converter and field oriented induction motor drive based upon specifications for a 10 hp squirrel cage dynamometer and a 20 kHz parallel resonant HF AC link is discussed. The induction machine is designed to deliver 10 hp or 7.46 kW when operated as an AC-dynamo with power fed back to the source through the converter. Results presented reveal that the proposed power level requires additional energy storage elements to overcome difficulties with a peak link voltage variation problem that limits reaching to the desired power level. The power level test of the second generation converter after the

  19. Real-time modeling and controls analysis using the MMS and the IBM advanced control system (ACS)

    The Penn State Nuclear Engineering Department has been used the EPRI sponsored Modular Modeling System (MMS) for research and education since 1985. The new capability presented in this paper is the adaptation of the MMS modeling procedure to produce a real-time interactive simulator. The technique additionally uses existing features of the Advanced Continuous Simulation Language (ACSL) and a commercially available control system for industrial applications, the IBM Advanced Control System (ACS). In the university environment, the IBM ACS mainframe software is used to effect the real-time interactive simulator capability. Successful demonstration of the basic mechanics for converting an existing batch mode MMS simulation to a real-time simulator using the ACS has been achieved for the MMS Deaerator example model. Future near-term work is expected to produce a real-time simulation of a primary loop of a Nuclear Steam Supply System that is used in an undergraduate Systems Interaction Course at Penn State

  20. Lowest of AC-DC power output for electrostrictive polymers energy harvesting systems

    Meddad, Mounir; Eddiai, Adil; Hajjaji, Abdelowahed; Guyomar, Daniel; Belkhiat, Saad; Boughaleb, Yahia; Chérif, Aida

    2013-11-01

    Advances in technology led to the development of electronic circuits and sensors with extremely low electricity consumption. At the same time, structural health monitoring, technology and intelligent integrated systems created a need for wireless sensors in hard to reach places in aerospace vehicles and large civil engineering structures. Powering sensors with energy harvesters eliminates the need to replace batteries on a regular basis. Scientists have been forced to search for new power source that are able to harvested energy from their surrounding environment (sunlight, temperature gradients etc.). Electrostrictive polymer belonging to the family of electro-active polymers, offer unique properties for the electromechanical transducer technology has been of particular interest over the last few years in order to replace conventional techniques such as those based on piezoelectric or electromagnetic, these materials are highly attractive for their low-density, with large strain capability that can be as high as two orders of magnitude greater than the striction-limited, rigid and fragile electroactive ceramics. Electrostrictive polymers sensors respond to vibration with an ac output signal, one of the most important objectives of the electronic interface is to realize the required AC-DC conversion. The goal of this paper is to design an active, high efficiency power doubler converter for electrostrictive polymers exclusively uses a fraction of the harvested energy to supply its active devices. The simulation results show that it is possible to obtain a maximum efficiency of the AC-DC converter equal to 80%. Premiliminary experimental measurements were performed and the results obtained are in good agreement with simulations.

  1. dc and ac Josephson effect in a superconductor endash Luttinger-liquid endash superconductor system

    We calculate both the dc and the ac Josephson current through a 1-D system of interacting electrons, connected to two superconductors by tunnel junctions. We treat the (repulsive) Coulomb interaction in the framework of the one-channel, spin-1/2 Luttinger model. The Josephson current is obtained for two geometries of experimental relevance: a quantum wire and a ring. At T=0, the critical current is found to decay algebraically with increasing distance d between the junctions. The decay is characterized by an exponent which depends on the strength of the interaction. At finite temperatures T, lower than the superconducting transition temperature Tc, there is a crossover from algebraic to exponential decay of the critical current as a function of d, at a distance of the order of ℎvF/kBT. Moreover, the dependence of critical current on temperature shows nonmonotonic behavior. If the Luttinger liquid is confined to a ring of circumference L, coupled capacitively to a gate voltage and threaded by a magnetic flux, the Josephson current shows remarkable parity effects under the variation of these parameters. For some values of the gate voltage and applied flux, the ring acts as a π junction. These features are robust against thermal fluctuations up to temperatures on the order of ℎvF/kBL. For the wire geometry, we have also studied the ac-Josephson effect. The amplitude and the phase of the time-dependent Josephson current are affected by electron-electron interactions. Specifically, the amplitude shows pronounced oscillations as a function of the bias voltage due to the difference between the velocities of spin and charge excitations in the Luttinger liquid. Therefore, the ac-Josephson effect can be used as a tool for the observation of spin-charge separation. copyright 1996 The American Physical Society

  2. Insulation measurement and supervision in live AC and DC unearthed systems

    Olszowiec, Piotr

    2014-01-01

    Low voltage unearthed (IT) AC and DC systems are commonly applied for supply of power and control circuits in industry, transportation, medical objects etc. The main reasons for their use are high reliability and numerous advantages offered by isolating them against ground. Insulation level is a decisive factor for networks operational reliability and safety. Insufficient insulation-to-ground resistance can cause various disturbances. Though ground faults in IT systems do not make networks operation impossible, they may cause severe problems with their safe functioning. In this book the most important issues concerning normal operation and ground fault phenomena are described in concise form. Numerous methods of insulation resistance and capacitance measurement in live circuits are presented. Important other procedures of  these parameters determination based on measurement and calculation are explained and reviews of selected insulation resistance measurement devices as well as earth fault locating systems ...

  3. Insulation measurement and supervision in live AC and DC unearthed systems

    Olszowiec, Piotr

    2013-01-01

    Low voltage unearthed (IT) AC and DC systems are commonly applied for supply of power and control circuits in industry, transportation, medical objects etc. The main reasons for their use are high reliability and numerous advantages offered by isolating them against ground. Insulation level is a decisive factor for networks operational reliability and safety. Insufficient insulation-to-ground resistance can cause various disturbances. Though ground faults in IT systems do not make networks operation impossible, they may cause severe problems with their safe functioning. In this book the most important issues concerning normal operation and ground fault phenomena are described in concise form. Numerous methods of insulation resistance and capacitance measurement in live circuits are presented. Important other procedures of  these parameters determination based on measurement and calculation are explained and reviews of selected insulation resistance measurement devices as well as earth fault locating systems ...

  4. Research of novel oscillating wire feeding system using the AC servo motor

    杨世彦; 于志; 刘喆

    2003-01-01

    With the background of the control of additional mechanical force droplet transfer in MIG/MAG welding, regarding the AC servo motor as core, a novel oscillating wire feeding system has been developed with excellent performances of control and dynamic acceleration which is tested. System constitution and operation principle are introduced in this paper. Influences of parameters on dynamic acceleration performance are analyzed and discussed emphatically, such as oscillating frequency, oscillating amplitude and draw-back speed. Experimental result indicates that according to the technique of welding control, the novel wire feeding system responds rapidly to various kinds of control orders of wire feeding and draw-back, and realizes flexible control of welding wire axial movement, including dynamic shifting,oscillating and so on.

  5. Ranking transmission projects in large scale systems using an AC power flow model; Priorizacao de obras em sistemas de grande porte usando um modelo AC da rede

    Melo, A.C.G. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil); Fontoura Filho, R.N. [ELETROBRAS, Rio de Janeiro, RJ (Brazil); Peres, L.A.P. Pecorelli [FURNAS, Rio de Janeiro, RJ (Brazil); Morozowski Filho, M. [Santa Catarina Univ., Florianopolis, SC (Brazil)

    1994-12-31

    Initially, this paper summarizes the approach developed by the Brazilian Planning Criteria Working Group (GTCP/ELETROBRAS) for identifying which subset of transmission investments should be postponed to meet a pre-stablished budget constraint with the least possible impact on system performance. Next, this paper presents the main features of the computational model PRIO, which allows the application of the ranking process to large scale power systems (2,000 buses and 3,000 circuits), with as many as 100 projects to be ranked. In this model, the adequacy analysis of each system state is carried out through an AC power flow coupled to a successive linear programming based remedial actions model. Case studies with the IEEE-RTS system and a configuration of the Brazilian Southeastern are presented and discussed. (author) 7 refs., 6 figs., 5 tabs.

  6. Evaluation of reliability of on-site A.C. power systems based on maintenance records

    To the end of ascertain in what extent the evaluation of reliability of emergency diesel generators (D.G.) can be improved by means of a deeper knowledge of their operating history a study has been carried-out on 21 D.G. sets: 4 D.G. of the Caorso nuclear plant (BWR, 870 MWe) and 17 D.G. in service at 6 steam-electric fossil-fuelled plants. The major points of interest resulting from this study are: 1) reliability assessments of A.C. on-site power Systems, made on the basis of outcomes of surveillance tests, may lead to results which overestimate the real performance. 2) the unreliability of a redundant System of stand-by components is determined in large extent by unavailabilities due to scheduled and unscheduled maintenance, latent failures, tests. (authors)

  7. The sluggs survey: HST/ACS mosaic imaging of the NGC 3115 globular cluster system

    Jennings, Zachary G.; Romanowsky, Aaron J.; Brodie, Jean P.; Arnold, Jacob A. [University of California Observatories, Santa Cruz, CA 95064 (United States); Strader, Jay [Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan, MI 48824 (United States); Lin, Dacheng; Irwin, Jimmy A.; Wong, Ka-Wah [Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487 (United States); Sivakoff, Gregory R., E-mail: zgjennin@ucsc.edu [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)

    2014-08-01

    We present Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) g and z photometry and half-light radii R {sub h} measurements of 360 globular cluster (GC) candidates around the nearby S0 galaxy NGC 3115. We also include Subaru/Suprime-Cam g, r, and i photometry of 421 additional candidates. The well-established color bimodality of the GC system is obvious in the HST/ACS photometry. We find evidence for a 'blue tilt' in the blue GC subpopulation, wherein the GCs in the blue subpopulation get redder as luminosity increases, indicative of a mass-metallicity relationship. We find a color gradient in both the red and blue subpopulations, with each group of clusters becoming bluer at larger distances from NGC 3115. The gradient is of similar strength in both subpopulations, but is monotonic and more significant for the blue clusters. On average, the blue clusters have ∼10% larger R {sub h} than the red clusters. This average difference is less than is typically observed for early-type galaxies but does match that measured in the literature for the Sombrero Galaxy (M104), suggesting that morphology and inclination may affect the measured size difference between the red and blue clusters. However, the scatter on the R {sub h} measurements is large. We also identify 31 clusters more extended than typical GCs, which we term ultra-compact dwarf (UCD) candidates. Many of these objects are actually considerably fainter than typical UCDs. While it is likely that a significant number will be background contaminants, six of these UCD candidates are spectroscopically confirmed as NGC 3115 members. To explore the prevalence of low-mass X-ray binaries in the GC system, we match our ACS and Suprime-Cam detections to corresponding Chandra X-ray sources. We identify 45 X-ray-GC matches: 16 among the blue subpopulation and 29 among the red subpopulation. These X-ray/GC coincidence fractions are larger than is typical for most GC systems, probably due to the increased

  8. Coordinated Stability Control of Wind-Thermal Hybrid AC/DC Power System

    Zhiqing Yao

    2015-01-01

    Full Text Available The wind-thermal hybrid power transmission will someday be the main form of transmitting wind power in China but such transmission mode is poor in system stability. In this paper, a coordinated stability control strategy is proposed to improve the system stability. Firstly, the mathematical model of doubly fed wind farms and DC power transmission system is established. The rapid power controllability of large-scale wind farms is discussed based on DFIG model and wide-field optical fiber delay feature. Secondly, low frequency oscillation and power-angle stability are analyzed and discussed under the hybrid transmission mode of a conventional power plant with wind farms. A coordinated control strategy for the wind-thermal hybrid AC/DC power system is proposed and an experimental prototype is made. Finally, real time simulation modeling is set up through Real Time Digital Simulator (RTDS, including wind power system and synchronous generator system and DC power transmission system. The experimental prototype is connected with RTDS for joint debugging. Joint debugging result shows that, under the coordinated control strategy, the experimental prototype is conductive to enhance the grid damping and effectively prevents the grid from occurring low frequency oscillation. It can also increase the transient power-angle stability of a power system.

  9. Eri silkworm (Samia ricini), a non-mulberry host system for AcMNPV mediated expression of recombinant proteins.

    Hosamani, Madhusudan; Basagoudanavar, Suresh H; Sreenivasa, B P; Inumaru, Shigeki; Ballal, Chandish R; Venkataramanan, Ramamurthy

    2015-12-20

    The baculovirus expression system (BVES) based on Autographa californica nucleopolyhedrovirus (AcMNPV) is widely used for the expression of eukaryotic proteins. Several insect cells/larvae that are permissive to AcMNPV have been routinely used as hosts to express heterologous proteins. Domesticated Eri silkworm (Samia ricini), reared in many parts of India, Japan and China, is a non-mulberry silkworm. The present study shows that the Eri silkworm larvae are susceptible to intra-haemocoelical inoculation of AcMNPV. The virus replicates in the larva, as indicated by an increased viral loads in the haemolymph upon injection of a recombinant AcMNPV carrying green fluorescent protein gene. The virus showed localized replication in different tissues including the fat body, haemocytes, tracheal matrix and in the Malphigian tubules. The larval system was successfully used to express heterologous protein, by infecting with a recombinant AcMNPV carrying the 3ABC coding sequence of foot-and-mouth disease virus (FMDV). The study shows that the Eri silkworm larva can be a potential alternative bioreactor, for scaling up of the recombinant proteins employing the baculovirus system. PMID:26467714

  10. A Series-LC-Filtered Active Damper with Grid Disturbance Rejection for AC Power-Electronics-Based Power Systems

    Wang, Xiongfei; Pang, Ying; Loh, Poh Chiang;

    2015-01-01

    This letter proposes an active damper with a series LC filter for suppressing resonances in an ac power-electronics-based power system. The added series filter capacitor helps to withstand most of the system voltage, hence, allowing a lower rated converter to be used for implementing the active...

  11. Magnetic behaviour of the UCuxGey system by AC magnetic susceptibility measurements

    We have analyzed the temperature dependence of the AC susceptibility, χac(T), of UCuxGey samples (0.800≤x, y≤1.00) applying various frequencies and magnetic field strengths up to 1 T. This was done in order to verify the reentrant ferromagnetic behaviour of UCuxGe and the antiferromagnetic behaviour of UCuGey previously observed by DC susceptibility experiments. Our χac results are discussed on the basis of existing theories. (orig.)

  12. Energy saving measures for automotive air conditioning (AC) system in the tropics

    Subiantoro, Alison; Ooi, Kim Tiow; Stimming, Ulrich

    2014-01-01

    Air conditioning (AC) is an integral component of modern cars in the tropics. However, AC usage in this region consumes a large amount of energy. In conventional internal combustion engine cars, it consumes up to 30% of the fuel, while in battery electric cars, AC may reduce the battery range by up to 40%. Fortunately, there are various ways to improve the efficiency of automotive ACs in the tropics. In this paper, three energy saving measures are discussed. These include a higher indoor temp...

  13. Harmonic Analysis of AC-DC Topologies and their Impacts on Power Systems

    Mukhtiar Ahmed Mahar

    2011-01-01

    Full Text Available Power Electronic Converters are commonly used in different applications because of high efficiency and low cost. Due to latest advancement in semiconductor devices it is difficult to draw the boundaries for applications of power electronic topologies. These topologies are variable structure systems and generate harmonics during the operation which will affect the power quality when are connected to system network. Rectifier is a big family of converters and used when ac-dc conversion is needed. These converters are widely used in distribution system. Therefore, it is necessary to predict the harmonic levels of these converters and also observe their impacts on system network. Pakistan now days facing serious energy crises specially, in power sector due to increase in load demand. To bridge the gap between load demand and generation of electricity, various steps are taken by power companies and government. The steps include the up gradation of existing power plants, generation of power from rental power plants, installation of renewable power sources, taking different steps of demand side management etc. But efforts of power companies on power quality is still lacking. This research work focuses on power quality of the system network. In this work, harmonics of single phase and three phase full bridge diode rectifiers are analyzed by using the fast fourier transform method of MATLAB. The effects of harmonics on the system network are also discussed.

  14. Simple uniaxial pressure device for ac-susceptibility measurements suitable for closed cycle refrigerator system.

    Arumugam, S; Manivannan, N; Murugeswari, A

    2007-06-01

    A simple design of the uniaxial pressure device for the measurement of ac-susceptibility at low temperatures using closed cycle refrigerator system is presented for the first time. This device consists of disc micrometer, spring holder attachment, uniaxial pressure cell, and the ac-susceptibility coil wound on stycast bobbin. It can work under pressure till 0.5 GPa and at the temperature range of 30-300 K. The performance of the system at ambient pressure is tested and calibrated with standard paramagnetic salts [Gd(2)O(3), Er(2)O(3), and Fe(NH(4)SO(4))(2)6H(2)O], Fe(3)O(4), Gd metal, Dy metal, superconductor (YBa(2)Cu(3)O(7)), manganite (La(1.85)Ba(0.15)MnO(3)), and spin glass material (Pr(0.8)Sr(0.2)MnO(3)). The performance of the uniaxial pressure device is demonstrated by investigating the uniaxial pressure dependence of La(1.85)Ba(0.15)MnO(3) single crystal with P||c axis. The Curie temperature (T(c)) decreases as a function of pressure with P||c axis (dT(c)dP(||c axis)=-11.65 KGPa) up to 46 MPa. The design is simple, is user friendly, and does not require pressure calibration. Measurement can even be made on thin and small size oriented crystals. The failure of the coil is remote under uniaxial pressure. The present setup can be used as a multipurpose uniaxial pressure device for the measurement of Hall effect and thermoelectric power with a small modification in the pressure cell. PMID:17614625

  15. Stability Analysis of Three-Phase AC Power Systems Based on Measured D-Q Frame Impedances

    Wen, Bo

    2015-01-01

    Small-signal stability is of great concern for distributed power systems with a large number of regulated power converters. These converters are constant-power loads (CPLs) exhibit a negative incremental input resistance within the output voltage regulation bandwidth. In the case of dc systems, design requirements for impedances that guarantee stability have been previously developed and are used in the design and specification of these systems. In terms of three-phase ac systems, a mathemati...

  16. Development of an in-line filter to prevent intrusion of NO2 toxic vapors into A/C systems

    Meneghelli, Barry; Mcnulty, R. J.; Springer, Mike; Lueck, Dale E.

    1995-01-01

    The hypergolic propellant nitrogen tetroxide (N2O4 or NTO) is routinely used in spacecraft launched at Kennedy Space Center (KSC) and Cape Canaveral Air Station (CCAS). In the case of a catastrophic failure of the spacecraft, there would be a release of the unspent propellant in the form of a toxic cloud. Inhalation of this material at downwind concentrations which may be as high as 20 parts per million (ppm) for 30 minutes in duration, may produce irritation to the eyes, nose and respiratory tract. Studies at both KSC and CCAS have shown that the indoor concentrations of N2O4 during a toxic release may range from 1 to 15 ppm and depend on the air change rate (ACR) for a particular building and whether or not the air conditioning (A/C) system has been shut down or left in an operating mode. This project was initiated in order to assess how current A/C systems could be easily modified to prevent personnel from being exposed to toxic vapors. A sample system has been constructed to test the ability of several types of filter material to capture the N2O4 vapors prior to their infiltration into the A/C system. Test results will be presented which compare the efficiencies of standard A/C filters, water wash systems, and chemically impregnated filter material in taking toxic vapors out of the incoming air stream.

  17. Vector control of three-phase AC machines system development in the practice

    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.

  18. A Secondary Voltage Control Method for an AC/DC Coupled Transmission System Based on Model Predictive Control

    Xu, Fengda; Guo, Qinglai; Sun, Hongbin;

    2015-01-01

    For an AC/DC coupled transmission system, the change of transmission power on the DC lines will significantly influence the AC systems’ voltage. This paper describes a method to coordinated control the reactive power of power plants and shunt capacitors at DC converter stations nearby, in order to...... keep the voltage of the pilot bus tracking its set point considering the DC system’s transmission schedule change. The approach is inspired by model predictive control (MPC) to compensate for predictable voltage change affected by DC side transmission power flow and the potential capacitor switching at...

  19. The vibration research of the AC dipole-girder system for CSNS/RCS

    Renhong, Liu; Huamin, Qu; Ling, Kang; Motuo, Wang; Guangyuan, Wang; Haijing, Wang

    2013-01-01

    China spallation neutron source(CSNS) is a high intensity proton accelerator based facility, and its accelerator complex includes two main parts: an H- linac and a rapid cycling synchrotron(RCS). The rcs accumulates the 80MeV proton beam, and accelerates it to 1.6GeV, with a repetition rate of 25 Hz. The AC dipole of the RCS is operated at a 25Hz sinusoidal alternating current which causes severe vibration. The vibration will influence the long-term safety and reliable operation of the magnet. The dipole magnet of RCS is active vibration equipment which is different with ground vibration accelerator. It is very important to design and research the dynamic characteristic of the dipole-girder system. This paper takes the dipole and girder as a specific model system, a method for researching the dynamic characteristic of the system is put forward by combining theoretical calculation with experimental testing. The ansys simulation method plays a very important role in the girder structure design stage. With the m...

  20. Application of Multi-Objective Evolutionary Algorithm for Optimal Reactive Power Dispatch with Flexible AC Transmission System Devices

    Abdarrazak OUALI; Hsan HADJ ABDALLAH; Tawfik GUESMI; Ismail MAROUANI

    2011-01-01

    Because their capability to change the network parameters with a rapid response and enhanced flexibility, flexible AC transmission system (FACTS) devices have taken more attention in power systems operations as improvement of voltage profile and minimizing system losses. In this way, this paper presents a multi-objective evolutionary algorithm (MOEA) to solve optimal reactive power dispatch (ORPD) problem with FACTS devices. This nonlinear multi-objective problem (MOP) consists to minimize si...

  1. An AC modulated near infrared gain calibration system for a "Violin-Mode" transimpedance amplifier, intended for advanced LIGO suspensions.

    Lockerbie, N A; Tokmakov, K V

    2016-07-01

    The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which a 40 kg test-mass/mirror is suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation, and a "tall-thin" rectangular silicon photodiode detector, which together were to bracket the fibre under test. The photodiode was positioned so as to be sensitive (primarily) to transverse "Violin-Mode" vibrations of such a fibre, via the oscillatory movement of the shadow cast by the fibre, as this moved across the face of the detector. In this prototype shadow sensing system the photodiode was interfaced to a purpose-built transimpedance amplifier, this having both AC and DC outputs. A quasi-static calibration was made of the sensor's DC responsivity, i.e., incremental rate of change of output voltage versus fibre position, by slowly scanning a fused-silica fibre sample transversely through the illuminating beam. The work reported here concerns the determination of the sensor's more important AC (Violin-Mode) responsivity. Recognition of the correspondence between direct AC modulation of the source, and actual Violin-Mode signals, and of the transformative role of the AC/DC gain ratio for the amplifier, at any modulation frequency, f, resulted in the construction of the AC/DC calibration source described here. A method for determining in practice the transimpedance AC/DC gain ratio of the photodiode and amplifier, using this source, is illustrated by a specific numerical example, and the gain ratio for the prototype sensing system is reported over the frequency range 1 Hz-300 kHz. In fact, a maximum DC responsivity of 1.26 kV.m(-1) was measured using the prototype photodiode sensor and amplifier discussed here. Therefore, the measured AC/DC transimpedance gain

  2. Enhancing power transfer capability through flexible AC transmission system devices:a review

    Fadi M ALBATSH; Saad MEKHILEF; Shameem AHMAD; H MOKHLIS; M A HASSAN

    2015-01-01

    Global demand for power has significantly increased, but power generation and transmission capacities have not increased proportionally with this demand. As a result, power consumers suffer from various problems, such as voltage and frequency instability and power quality issues. To overcome these problems, the capacity for available power transfer of a transmission network should be enhanced. Researchers worldwide have addressed this issue by using flexible AC transmission system (FACTS) devices. We have conducted a comprehensive review of how FACTS controllers are used to enhance the avail-able transfer capability (ATC) and power transfer capability (PTC) of power system networks. This review includes a discussion of the classification of different FACTS devices according to different factors. The popularity and applications of these devices are discussed together with relevant statistics. The operating principles of six major FACTS devices and their application in increasing ATC and PTC are also presented. Finally, we evaluate the performance of FACTS devices in ATC and PTC im-provement with respect to different control algorithms.

  3. Optimization approach to unified AC/DC power flow applied to traction systems with catenary voltage constraints

    Coto García, Manuel; Arboleya Arboleya, Pablo; González Morán, Cristina

    2013-01-01

    This paper presents two innovative contributions related to the combined AC/DC power ow in railway power supply systems (RPSS). First, most of the power ow equations (the linear ones) are expressed in a compact matrix form by using graph theory based protocol. Such approach simpli- es the statement of the uni ed power ow problem and allows the train motion to be modeled without varying the system topology. Second, the problem is formulated as an Optimization Pro...

  4. An electrochemical study of corrosion protection by primer-topcoat systems on 4130 steel with ac impedance and dc methods

    Mendrek, M. J.; Higgins, R. H.; Danford, M. D.

    1988-01-01

    To investigate metal surface corrosion and the breakdown of metal protective coatings, the ac impedance method is applied to six systems of primer coated and primer topcoated 4130 steel. Two primers were used: a zinc-rich epoxy primer and a red lead oxide epoxy primer. The epoxy-polyamine topcoat was used in four of the systems. The EG and G-PARC Model 368 ac impedance measurement system, along with dc measurements with the same system using the polarization resistance method, were used to monitor changing properties of coated 4230 steel disks immersed in 3.5 percent NaCl solutions buffered at pH 5.4 over periods of 40 to 60 days. The corrosion system can be represented by an electronic analog called an equivalent circuit consisting of resistors and capacitors in specific arrangements. This equivalent circuit parallels the impedance behavior of the corrosion system during a frequency scan. Values for the resistors and capacitors, that can be assigned in the equivalent circuit following a least-squares analysis of the data, describe changes that occur on the corroding metal surface and in the protective coatings. Two equivalent circuits have been determined that predict the correct Bode phase and magnitude of the experimental sample at different immersion times. The dc corrosion current density data are related to equivalent circuit element parameters. Methods for determining corrosion rate with ac impedance parameters are verified by the dc method.

  5. Reliability evaluation of emergency AC power systems based on operating experience at U.S. nuclear power plants

    The reliability of emergency AC power Systems has been under study at the U.S. Nuclear Regulatory Commission and by its contractors for several years. This paper provides the results of work recently performed to evaluate past U.S. nuclear power plant emergency AC power System reliability performance using system level data. Operating experience involving multiple diesel generator failures, unavailabilities, and simultaneous occurrences of failures and out of service diesel generators were used to evaluate reliability performance at individual nuclear power plants covering a 9 year period from 1976 through 1984. The number and nature of failures and distributions of reliability evaluation results are provided. The results show that plant specific performance varied considerably during the period with a large number achieving high reliability performance and a smaller number accounting for lower levels of reliability performance. (author)

  6. Damping effects of Supplementary Control Signals for Enhancement of Transient Stability in AC-DC Power Systems

    Uma Vani M

    2010-07-01

    Full Text Available This paper discusses the impact of HVDC on Power System Stability and proposes a novel controlmechanism to augment the system angle stability. The effectiveness of the proposed controller is demonstrated by asingle machine-infinite bus system example. The performance of this controller, in comparison to the conventionalP and P-I controllers, is found to be very effective as a supplementary PID controller in damping generator rotoroscillations. The supplementary controls using signals derived from the AC systems to modulate the DC quantitiesis presented in this paper.

  7. Analyze and experiment on AC magnetic field's effect to fiber optic gyroscopes in compact stabilization control systems

    Zhang, Chao; Mao, Yao; Tian, Jing; Li, Zhijun

    2015-10-01

    Fiber optic gyroscopes (FOG) are getting more and more attention in areas such as stabilization control systems as they are all solid state and have a wide bandwidth. In stabilization systems that require wide bandwidth control, motors are usually used as actuating mechanism for active disturbance restrain. Voice coil motors (VCMs) are usually used in compact stabilization systems that require large torque and fast response. However, AC magnetic field, which can affect the output of FOG due to Faraday effect, will be generated during operation of VCMs. The frequency range affected by the AC magnetic field to the FOG's output is the same as VCMs drive signal frequency range, which is also exactly the stabilization system's working range. Therefore the effect of the AC magnetic field to FOGs must be evaluated to verify the feasibility of a stable system design that uses both FOGs and VCMs. In this article, the basic structure and operating principle of stabilization system is introduced. The influence of AC magnetic field to FOG is theoretically analyzed. The magnetic field generated by VCMs is numerically simulated based on the theory deduction of the magnetic field near energized wires. To verify the influence of the VCM generated magnetic field to the FOGs in practical designs, a simplified random fiber coil model is built for it's hard to accurately test the exact polarize axis's twisting rate in a fiber coil. The influence to the FOG's output of different random coil model is simulated and the result shows a same trend that the influence of the VCM's magnetic field to the FOG is reduced as the distance between the VCM and the FOG increasing. The influence of a VCM to a FOG with the same parameters is experimentally tested. In the Fourier transformed FOG data the same frequency point as the VCM drive signal frequency can be read. The result fit simulated result that as the distance increases, the influence decreases. The amplitude of the frequency point is just

  8. Module Twelve: Series AC Resistive-Reactive Circuits; Basic Electricity and Electronics Individualized Learning System.

    Bureau of Naval Personnel, Washington, DC.

    The module covers series circuits which contain both resistive and reactive components and methods of solving these circuits for current, voltage, impedance, and phase angle. The module is divided into six lessons: voltage and impedance in AC (alternating current) series circuits, vector computations, rectangular and polar notation, variational…

  9. Formation of compounds in the quasi-binary systems AcX4-MX2 (Ac = Th, U; M = Ca, Sr, Ba, Eu, Ge, Sn, Pb; X = Br, I)

    T,x-phase diagrams of the systems ThI4-SnI2, ThI4-PbI2, ThI4-CaI2 and ThI4-SrI2 were established using thermoanalysis and X-ray methods. The only ternary compounds have a 1:1 composition. Further AcMX6 compounds (Ac: Th, U; M: Ca, Sr, Ba, Eu, Ge, Sn, Pb; X: Br, I) were synthesized and their structures investigated. Four structure types are found depending on the temperature and the Ac/M combinations. The structures of γ-ThSnI6 and β-ThSnI6 were determined with single crystal methods as representatives of a whole series of isotypic compounds. (orig.)

  10. Near-optimal order-reduced control for A/C (air-conditioning) system of EVs (electric vehicles)

    This work is aimed to investigate the regulation problem for thermal comfortableness and propose control strategies for cabin environment of EVs (electric vehicles) by constructing a reduced-scale A/C (air-conditioning) system which mainly consists of two modules: ECB (environmental control box) and AHU (air-handling unit). Temperature and humidity in the ECB can be regulated by AHU via cooling, heating, mixing air streams and adjusting speed of fans. To synthesize the near-optimal controllers, the mathematical model for the system thermodynamics is developed by employing the equivalent lumped heat capacity approach, energy/mass conservation principle and the heat transfer theories. In addition, from the clustering pattern of system eigenvalues, the thermodynamics of the interested system can evidently be characterized by two-time-scale property. That is, the studied system can be decoupled into two subsystems, slow mode and fast mode, by singular perturbation technique. As to the optimal control strategies for EVs, by taking thermal comfortableness, humidity and energy consumption all into account, a series of optimal controllers is synthesized on the base of the order-reduced thermodynamic model. The feedback control loop for the experimental test rig is examined and realized by the aid of the control system development kit dSPACE DS1104 and the commercial software MATLAB/Simulink. To sum up, the intensive computer simulations and experimental results verify that the performance of the near-optimal order-reduced control law is almost as superior as that of standard LQR (Linear-Quadratic Regulator). - Highlights: • A reduced-scale test rig for A/C (air-conditioning) system to imitate the temperature/humidity of cabin in EV (electric vehicle) is constructed. • The non-linear thermodynamic model of A/C system can be decoupled by singular perturbation technique. • The temperature/humidity in cabin is regulated to the desired values by proposed optimal

  11. Error Assessment of Solar Irradiance Forecasts and AC Power from Energy Conversion Model in Grid-Connected Photovoltaic Systems

    Gianfranco Chicco

    2015-12-01

    Full Text Available Availability of effective estimation of the power profiles of photovoltaic systems is essential for studying how to increase the share of intermittent renewable sources in the electricity mix of many countries. For this purpose, weather forecasts, together with historical data of the meteorological quantities, provide fundamental information. The weak point of the forecasts depends on variable sky conditions, when the clouds successively cover and uncover the solar disc. This causes remarkable positive and negative variations in the irradiance pattern measured at the photovoltaic (PV site location. This paper starts from 1 to 3 days-ahead solar irradiance forecasts available during one year, with a few points for each day. These forecasts are interpolated to obtain more irradiance estimations per day. The estimated irradiance data are used to classify the sky conditions into clear, variable or cloudy. The results are compared with the outcomes of the same classification carried out with the irradiance measured in meteorological stations at two real PV sites. The occurrence of irradiance spikes in “broken cloud” conditions is identified and discussed. From the measured irradiance, the Alternating Current (AC power injected into the grid at two PV sites is estimated by using a PV energy conversion model. The AC power errors resulting from the PV model with respect to on-site AC power measurements are shown and discussed.

  12. A Sequential AC/DC Power Flow Algorithm for Networks Containing Multi-terminal VSC HVDC Systems

    Beerten, Jef; Cole, Stijn; Belmans, Ronnie

    2010-01-01

    In this paper, a sequential AC/DC power flow algorithm is proposed to solve networks containing Multi-terminal Voltage Source Converter High Voltage Direct Current (VSC MTDC) systems. In VSC HVDC technology, the converter losses add up to a significant fraction of the overall system losses. However, they are often neglected or not taken into account in a proper manner in VSC HVDC power flows. The algorithm put forward in this paper takes the converter losses into account using a generalized c...

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

    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.

  14. Increased Ac excision (iae): Arabidopsis thaliana mutations affecting Ac transposition

    The maize transposable element Ac is highly active in the heterologous hosts tobacco and tomato, but shows very much reduced levels of activity in Arabidopsis. A mutagenesis experiment was undertaken with the aim of identifying Arabidopsis host factors responsible for the observed low levels of Ac activity. Seed from a line carrying a single copy of the Ac element inserted into the streptomycin phosphotransferase (SPT) reporter fusion, and which displayed typically low levels of Ac activity, were mutagenized using gamma rays. Nineteen mutants displaying high levels of somatic Ac activity, as judged by their highly variegated phenotypes, were isolated after screening the M2 generation on streptomycin-containing medium. The mutations fall into two complementation groups, iae1 and iae2, are unlinked to the SPT::Ac locus and segregate in a Mendelian fashion. The iae1 mutation is recessive and the iae2 mutation is semi-dominant. The iae1 and iae2 mutants show 550- and 70-fold increases, respectively, in the average number of Ac excision sectors per cotyledon. The IAE1 locus maps to chromosome 2, whereas the SPT::Ac reporter maps to chromosome 3. A molecular study of Ac activity in the iae1 mutant confirmed the very high levels of Ac excision predicted using the phenotypic assay, but revealed only low levels of Ac re-insertion. Analyses of germinal transposition in the iae1 mutant demonstrated an average germinal excision frequency of 3% and a frequency of independent Ac re-insertions following germinal excision of 22%. The iae mutants represents a possible means of improving the efficiency of Ac/Ds transposon tagging systems in Arabidopsis, and will enable the dissection of host involvement in Ac transposition and the mechanisms employed for controlling transposable element activity

  15. Predictive Current Control of a 7-level AC-DC back-to-back Converter for Universal and Flexible Power Management System

    Bifaretti, Steffano; Zanchetta, Pericle; Iov, Florin;

    2008-01-01

    The paper proposes a novel power conversion system for Universal and Flexible Power Management (UNIFLEX-PM) in Future Electricity Network. Its structure is based on a back-to-back three-phase AC-DC 7-level converter; each AC side is connected to a different PCC, representing the main grid and/or ...... numerous network conditions such as voltage unbalance, frequency excursions and harmonic distortion....

  16. AC/DC Power Conversion System Using 3/9 Multiphase Transformer

    Ahmad Hoteit

    2012-07-01

    Full Text Available The main idea of this paper is to build a 3/9 AC multiphase transformer for conversion into DC power through the rectifier circuit which contains 18 pulse rectification with a ripple factor less than 0.8% produced by the odd phase number 9. This modeling has been simulated using Orcad simulation software, the nine phases are out of the main three phase power lines, each phase is shifted from the other by 40o (360o/9, this type of transformer is often required in aerospace, railway and automobile applications.

  17. An 225Ac/213Bi generator system for therapeutic clinical applications: construction and operation

    A method for construction and operation of an 225Ac/213Bi generator capable of producing 25-100 mCi of 213Bi suitable for clinical antibody labeling is described. The generator has been designed to have an effective lifetime of several weeks, producing up to six therapeutic doses of radionuclide per day. To date, 57 clinical doses have been prepared and injected into patients using the described 213Bi generator. Factors such as radiation damage, radioprotection, iodide eluate chemistry, radiolabeling chemistry and radionuclidic purity are addressed

  18. A.c. susceptibility study of CaCl2 doped copper–zinc ferrite system

    A Y Lipare; P N Vasambekar; A S Vaingankar

    2003-08-01

    Polycrystalline soft ferrites, Zn$_x$ Cu$_{1–x}$ Fe2O4 ( = 0.30, 0.50, 0.70, 0.80 and 0.90), doped with controlled amount of calcium chloride (CaCl2) were prepared by standard ceramic route and studied for a.c. susceptibility. X-ray diffraction studies of the compositions reveal formation of single-phase cubic spinel. The values of lattice constant increase as doping percentage of CaCl2 increased from 0.01% to 0.05% and afterwards decrease slightly. The presence of chlorine ions is confirmed by absorption peak in far IR spectra near 650 cm-1 for all the samples. The variation of a.c. susceptibility with temperature shows the existence of single domain structure for = 0.3 and exhibits transition from single domain to multidomain structure with increased Ca2+ contents from 0.01 to 0.1%. The composition, = 0.5, shows multidomain structure independent of Ca2+ content. The samples for = 0.70, 0.80 and 0.90 show paramagnetic behaviour at and above room temperature.

  19. AC drive system with 4 in-wheel motor for high performance electric vehicle. Yonrin Kudo koseino denki jidoshayo AC drive system

    Terashima, M.; Ashikaga, T.; Mizuno, T. (Meidensha Corp., Tokyo (Japan)); Yamamoto, T.; Natori, K.; Fujiwara, N. (The Tokyo Electric Power Co. Inc., Tokyo (Japan))

    1994-01-20

    This paper describes the following matters on a driving motor and its control system used in the electric vehicle, IZA, that has achieved performance comparable to that of gasoline-fueled cars: a system has been employed that synchronous motors using rare earth magnets as the magnetic field are assembled into each of the four wheels to drive them directly. Taking into consideration that a maximum torque of about eight times that of the rating would be required, discussions have been given on effects of the magnetic saturation in the field, and a selection has been made on a magnet shape that can reduce torque pulsation of the motor. An incident of current uncontrollability caused by induction voltage in the motor during high rotation speeds has been avoided by demagnetization control to have achieved a speed of 176 km/h. The control system has been structured based on the control methods that consider the battery characteristics, inverter loss, and motor loss, realizing a torque control over a wide range. The motors, the inverters, and the drive system have been verified to have near design performance according to evaluation tests. 12 refs., 13 figs., 2 tabs.

  20. Application of ACS6000C Cycloconverter in the Hoist System of Coal Mine%ACS6000C交流调速技术在矿井提升系统的应用

    孟强; 廉鲁炜

    2013-01-01

    本文介绍一种全数字可编程模块化交流调速控制系统,ABB公司ACS6000C系统,其独特的应用和电机控制处理板(AMC3板),能进行高速动态信息处理以及对专门的控制系统进行调节和控制,在矿井提升机同步电机的调速控制应用中显现出高性能的响应和精确的力矩控制。实现了矿井提升机的安全、高效、稳定运行。%This paper introduces a digital programmable modular AC speed control system, ACS6000C system of ABB company, the applica-tion and motor unique control board (AMC3 board), can make high speed dynamic information processing and control and adjust the control system of the special, in the synchronous motor in mine hoist control showing response high performance and precise torque control applica-tions. The mine hoist safe, efficient and stable operation of machine.

  1. Emergency ac power systems operating experience at US nuclear power plants, 1976 through 1983

    Success and failure data of test and emergency starts of emergency ac power sources (diesel generators) at US nuclear power plants were collected and evaluated to estimate diesel generator reliability parameters. A regression analysis of the estimates of the probability of failure to start based on surveillance test data from 1976 through 1983 indicates that the probability of failure to start has been decreasing. However, the reliability of diesel generator performance during losses of off-site power for 1981 through 1983 was less than expected based on the test data estimates. The failures that occurred during losses of off-site power were reviewed to determine why the calculated failure to start was greater than expected, and possible explanations for this high value are presented. The subsystems involved in diesel generator subsystem failures were categorized to determine whether there were any dominant failure modes. The results indicate that further significant improvement in diesel generator reliability will require improvement of many subsystems

  2. Advanced Technology Application Station Blackout Core Damage Frequency Reduction - The Contribution of an AC Independent Core Residual Heat Removal System

    An event of station blackout (SBO) can result in severe core damage and undesirable consequences to the public and the environment. To cope with an SBO, nuclear reactors are provided with protection systems that automatically shut down the reactor, and with safety systems to remove the core residual heat. In order to reduce core damage frequency, the design of new reactors incorporates passive systems that rely only on natural forces to operate. This paper presents an evaluation of the SBO core damage frequency of a PWR reactor being designed in Brazil. The reactor has two core residual heat removal systems - an AC dependent system, and a passive system. Probabilistic safety assessment is applied to identify failure scenarios leading to SBO core damage. The SBO is treated as an initiating event, and fault trees are developed to model those systems required to operate in SBO conditions. Event trees are developed to assist in the evaluation of the possible combinations of success or failure of the systems required to cope with an SBO. The evaluation is performed using SAPHIRE, as the software for reliability and risk assessment. It is shown that a substantial reduction in the core damage frequency can be achieved by implementing the passive system proposed for the LABGENE reactor design. Keywords: Station blackout, passive safety system, core damage frequency. (author)

  3. Station Blackout Core Damage Frequency Reduction - The Contribution of an AC Independent Core Residual Heat Removal System

    An event of station blackout (SBO) can result in severe core damage and undesirable consequences to the public and the environment. To cope with an SBO, nuclear reactors are provided with protection systems that automatically shut down the reactor, and with safety systems to remove the core residual heat. In order to reduce core damage frequency, the design of new reactors incorporates passive systems that rely only on natural forces to operate. This paper presents an evaluation of the SBO core damage frequency of a PWR reactor being designed in Brazil. The reactor has two core residual heat removal systems - an AC dependent system, and a passive system. Probabilistic safety assessment is applied to identify failure scenarios leading to SBO core damage. The SBO is treated as an initiating event, and fault trees are developed to model those systems required to operate in SBO conditions. Event trees are developed to assist in the evaluation of the possible combinations of success or failure of the systems required to cope with an SBO. The evaluation is performed using SAPHIRE, as the software for reliability and risk assessment. It is shown that a substantial reduction in the core damage frequency can be achieved by implementing the passive system proposed for the LABGENE reactor design. Keywords: Station blackout, passive safety system, core damage frequency. (author)

  4. MOEA based design of decentralized controllers for LFC of interconnected power systems with nonlinearities, AC-DC parallel tie-lines and SMES units

    Ganapathy, S., E-mail: ganapathy1967@gmail.co [Department of Electrical Engineering, Annamalai University, Annamalainagar, Tamilnadu 608 002 (India); Velusami, S. [Department of Electrical Engineering, Annamalai University, Annamalainagar, Tamilnadu 608 002 (India)

    2010-05-15

    A new design of Multi-Objective Evolutionary Algorithm based decentralized controllers for load-frequency control of interconnected power systems with Governor Dead Band and Generation Rate Constraint nonlinearities, AC-DC parallel tie-lines and Superconducting Magnetic Energy Storage (SMES) units, is proposed in this paper. The HVDC link is used as system interconnection in parallel with AC tie-line to effectively damp the frequency oscillations of AC system while the SMES unit provides bulk energy storage and release, thereby achieving combined benefits. The proposed controller satisfies two main objectives, namely, minimum Integral Squared Error of the system output and maximum closed-loop stability of the system. Simulation studies are conducted on a two area interconnected power system with nonlinearities, AC-DC tie-lines and SMES units. Results indicate that the proposed controller improves the transient responses and guarantees the closed-loop stability of the overall system even in the presence of system nonlinearities and with parameter changes.

  5. MOEA based design of decentralized controllers for LFC of interconnected power systems with nonlinearities, AC-DC parallel tie-lines and SMES units

    A new design of Multi-Objective Evolutionary Algorithm based decentralized controllers for load-frequency control of interconnected power systems with Governor Dead Band and Generation Rate Constraint nonlinearities, AC-DC parallel tie-lines and Superconducting Magnetic Energy Storage (SMES) units, is proposed in this paper. The HVDC link is used as system interconnection in parallel with AC tie-line to effectively damp the frequency oscillations of AC system while the SMES unit provides bulk energy storage and release, thereby achieving combined benefits. The proposed controller satisfies two main objectives, namely, minimum Integral Squared Error of the system output and maximum closed-loop stability of the system. Simulation studies are conducted on a two area interconnected power system with nonlinearities, AC-DC tie-lines and SMES units. Results indicate that the proposed controller improves the transient responses and guarantees the closed-loop stability of the overall system even in the presence of system nonlinearities and with parameter changes.

  6. ac bidirectional motor controller

    Schreiner, K.

    1988-01-01

    Test data are presented and the design of a high-efficiency motor/generator controller at NASA-Lewis for use with the Space Station power system testbed is described. The bidirectional motor driver is a 20 kHz to variable frequency three-phase ac converter that operates from the high-frequency ac bus being designed for the Space Station. A zero-voltage-switching pulse-density-modulation technique is used in the converter to shape the low-frequency output waveform.

  7. Emergency ac power systems operating experience at U.S. nuclear power plants - 1976 through 1983

    Success and failure data of test and emergency starts of emergency ac power sources (diesel generators) at U.S. nuclear power plants were collected and evaluated to estimate diesel generator reliability parameters. A regression analysis of the estimates of the probability of failure to start based on surveillance test data from 1976 through 1983 indicates that the probability of failure to start has been decreasing. However, the reliability of diesel generator performance during losses of off-site power for 1981 through 1983 was less than expected based on the test data estimates. The failures that occurred during losses of off-site power were reviewed to determine why the calculated failure to start was greater than expected, and possible explanations for this high value are presented. The subsystems involved In diesel generator subsystem failures were categorized to determine whether there were any dominant failure modes. The results indicate that further significant Improvement in diesel generator reliability will require improvement of many subsystems. (author)

  8. Max Launch Abort System (MLAS) Pad Abort Test Vehicle (PATV) II Attitude Control System (ACS) Integration and Pressurization Subsystem Dynamic Random Vibration Analysis

    Ekrami, Yasamin; Cook, Joseph S.

    2011-01-01

    In order to mitigate catastrophic failures on future generation space vehicles, engineers at the National Aeronautics and Space Administration have begun to integrate a novel crew abort systems that could pull a crew module away in case of an emergency at the launch pad or during ascent. The Max Launch Abort System (MLAS) is a recent test vehicle that was designed as an alternative to the baseline Orion Launch Abort System (LAS) to demonstrate the performance of a "tower-less" LAS configuration under abort conditions. The MLAS II test vehicle will execute a propulsive coast stabilization maneuver during abort to control the vehicles trajectory and thrust. To accomplish this, the spacecraft will integrate an Attitude Control System (ACS) with eight hypergolic monomethyl hydrazine liquid propulsion engines that are capable of operating in a quick pulsing mode. Two main elements of the ACS include a propellant distribution subsystem and a pressurization subsystem to regulate the flow of pressurized gas to the propellant tanks and the engines. The CAD assembly of the Attitude Control System (ACS) was configured and integrated into the Launch Abort Vehicle (LAV) design. A dynamic random vibration analysis was conducted on the Main Propulsion System (MPS) helium pressurization panels to assess the response of the panel and its components under increased gravitational acceleration loads during flight. The results indicated that the panels fundamental and natural frequencies were farther from the maximum Acceleration Spectral Density (ASD) vibrations which were in the range of 150-300 Hz. These values will direct how the components will be packaged in the vehicle to reduce the effects high gravitational loads.

  9. Observations of spatiotemporal instabilities in the strong-driving regime of an AC-driven nonlinear Schr\\"odinger system

    Anderson, Miles; Coen, Stéphane; Erkintalo, Miro; Murdoch, Stuart G

    2016-01-01

    Localized dissipative structures (LDS) have been predicted to display a rich array of instabilities, yet systematic experimental studies have remained scarce. We have used a synchronously-driven optical fiber ring resonator to experimentally study LDS instabilities in the strong-driving regime of the AC-driven nonlinear Schr\\"odinger equation (also known as the Lugiato-Lefever model). Through continuous variation of a single control parameter, we have observed a string of theoretically predicted instability modes, including irregular oscillations and chaotic collapses. Beyond a critical point, we observe behaviour reminiscent of a phase transition: LDSs trigger localized domains of spatiotemporal chaos that invade the surrounding homogeneous state. Our findings directly confirm a number of theoretical predictions, and they highlight that complex LDS instabilities can play a role in experimental systems.

  10. Application of Multi-Objective Evolutionary Algorithm for Optimal Reactive Power Dispatch with Flexible AC Transmission System Devices

    Abdarrazak OUALI

    2011-12-01

    Full Text Available Because their capability to change the network parameters with a rapid response and enhanced flexibility, flexible AC transmission system (FACTS devices have taken more attention in power systems operations as improvement of voltage profile and minimizing system losses. In this way, this paper presents a multi-objective evolutionary algorithm (MOEA to solve optimal reactive power dispatch (ORPD problem with FACTS devices. This nonlinear multi-objective problem (MOP consists to minimize simultaneously real power loss in transmission lines and voltage deviation at load buses, by tuning parameters and searching the location of FACTS devices. The constraints of this MOP are divided to equality constraints represented by load flow equations and inequality constraints such as, generation reactive power sources and security limits at load buses. Two types of FACTS devices, static synchronous series compensator (SSSC and unified power flow controller (UPFC are considered. A comparative study regarding the effects of an SSSC and an UPFC on voltage deviation and total transmission real losses is carried out. The design problem is tested on a 6-bus system.

  11. A 65-kV insulated gate bipolar transistor switch applied in damped AC voltages partial discharge detection system

    Jiang, J.; Ma, G. M.; Luo, D. P.; Li, C. R.; Li, Q. M.; Wang, W.

    2014-02-01

    Damped AC voltages detection system (DAC) is a productive way to detect the faults in power cables. To solve the problems of large volume, complicated structure and electromagnetic interference in existing switches, this paper developed a compact solid state switch based on electromagnetic trigger, which is suitable for DAC test system. Synchronous electromagnetic trigger of 32 Insulated Gate Bipolar Transistors (IGBTs) in series was realized by the topological structure of single line based on pulse width modulation control technology. In this way, external extension was easily achieved. Electromagnetic trigger and resistor-capacitor-diode snubber circuit were optimized to reduce the switch turn-on time and circular layout. Epoxy encapsulating was chosen to enhance the level of partial discharge initial voltage (PDIV). The combination of synchronous trigger and power supply is proposed to reduce the switch volume. Moreover, we have overcome the drawback of the electromagnetic interference and improved the detection sensitivity of DAC by using capacitor storage energy to maintain IGBT gate driving voltage. The experimental results demonstrated that the solid-state switch, with compact size, whose turn-on time was less than 400 ns and PDIV was more than 65 kV, was able to meet the actual demands of 35 kV DAC test system.

  12. Online fault location on crossbonded AC cables in underground transmission systems

    F. Jensen, Christian; Bak, Claus Leth; Gudmundsdottir, Unnur Stella

    2014-01-01

    of a 245 kV crossbonded cable system, connecting the newly installed 400 MW Danish offshore wind farm Anholt to the main grid, are obtained and used to verify the proposed system. Furthermore, extensive simulation data created in PSCAD/EMTDC is used in order to examine the robustness of the system to......In this paper, a fault locator system specifically designed for crossbonded cables is described. Electromagnetic wave propagation theory for crossbonded cables with focus on fault location purposes is discussed. Based on this, the most optimal modal component and input signal to the fault locator...... system are identified. The fault locator system uses the Wavelet Transform both to create reliable triggers in the units and to estimate the fault location based on time domain signals obtained in the substations by two fault locator units. Field measurements of faults artificially created on a section...

  13. Adaptive Curtailment Plan with Energy Storage for AC/DC Combined Distribution Systems

    Seungmin Jung

    2016-08-01

    Full Text Available For developing a large-scale combined system with a number of distributed resources, an appropriate compensation strategy based on the system components and changeable condition must be configured to handle the characteristics of the internal systems. Since renewable sources generate various fluctuations, the compensation plans for the storage device connected along with the sources should be supported by a precise expectation method. A cooperative strategy involving the sharing of the DC section with environmentally sensitive generators, like photovoltaic system (PVs or waves, demands appropriate ESS compensation solutions, owing to its complexity. An active power-control algorithm with voltage-expectation based on the DC power flow is introduced in this paper and is applied in the designed case studies performed on the electromagnetic transient simulation. DC based multi-generation system is composed by applying tidal generator and super capacitor. To utilize wind energy, an offshore wind–wave generation system was utilized in the verification process.

  14. Online fault location on crossbonded AC cables in underground transmission systems

    F. Jensen, Christian; Bak, Claus Leth; Gudmundsdottir, Unnur Stella

    2014-01-01

    In this paper, a fault locator system specifically designed for crossbonded cables is described. Electromagnetic wave propagation theory for crossbonded cables with focus on fault location purposes is discussed. Based on this, the most optimal modal component and input signal to the fault locator system are identified. The fault locator system uses the Wavelet Transform both to create reliable triggers in the units and to estimate the fault location based on time domain signals obtained in th...

  15. Colloid Thruster for Attitude Control Systems (ACS) and Tip-off Control Applications Project

    National Aeronautics and Space Administration — Busek proposes to develop and deliver a complete engineering model colloid thruster system, capable of thrust levels and lifetimes required for spacecraft...

  16. Simultaneous distribution of AC and DC power

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  17. Online Fault Location on AC Cables in Underground Transmission Systems using Sheath Currents

    Jensen, Christian Flytkjær; Nanayakkarab, Kasun; Rajapakse, Athula;

    2014-01-01

    This paper studies online travelling wave methods for fault location on a crossbonded cable system using sheath currents. During the construction of the electrical connection to the 400 MW off shore wind farm Anholt, it was possible to perform measurements on a 38.4 km crossbonded cable system. At...

  18. The dissipative two-level system under strong ac-driving: a Floquet-van-Vleck approach

    Hausinger, Johannes

    2009-01-01

    We study the dissipative dynamics of a two-level system (TLS) exposed to strong ac-driving. By combing Floquet and Van Vleck perturbation theory in the TLS tunneling matrix element, we diagonalize the time-dependent Hamiltonian and provide corrections to the renormalized Rabi frequency of the TLS, which are valid for both a biased and unbiased TLS and go beyond the known high-frequency and rotating wave results. In order to mimick environmental influences on the TLS, we couple the system weakly to a thermal bath and solve analytically the corresponding Floquet-Bloch-Redfield master equation. We give a closed expression for the relaxation and dephasing rates of the TLS and discuss their behaviour under variation of the driving amplitude. Further, we examine the robustness of coherent destruction of tunneling (CDT) and driving-induced tunneling oscillations (DITO). We show that also for a moderate driving frequency an almost complete suppression of tunneling can be achieved and demonstrate the sensitiveness of ...

  19. Modeling and analysis of harmonic resonance in a power electronics based AC power system

    Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe; Wu, Weimin

    -based analysis approach is adopted and expanded to a meshed and balanced three-phase power network. An impedance ratio derivation method is proposed based on the nodal admittance matrix. By this means, the contribution of each inverter to the system resonance modes can be easily predicted by the Nyquist......The dynamic interactions among the interconnected power converters may bring in harmonic resonance in a power electronics based power system. This paper addresses this issue in a power system dominated by multiple current- and voltage-controlled inverters with LCL- and LC-filters. The impedance...... stability criterion. To validate the theoretical analysis, the time domain simulations and experimental tests on a three-inverter-based system are presented....

  20. Colloid Thruster for Attitude Control Systems (ACS) and Tip-off Control Applications Project

    National Aeronautics and Space Administration — We propose to develop and test key technologies needed for an integrated, high thrust colloid thruster system with no moving parts, for spacecraft attitude control...

  1. Modeling and analysis of harmonic resonance in a power electronics based AC power system

    Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe; Wu, Weimin

    2013-01-01

    The dynamic interactions among the interconnected power converters may bring in harmonic resonance in a power electronics based power system. This paper addresses this issue in a power system dominated by multiple current- and voltage-controlled inverters with LCL- and LC-filters. The impedance-based analysis approach is adopted and expanded to a meshed and balanced three-phase power network. An impedance ratio derivation method is proposed based on the nodal admittance matrix. By this means,...

  2. Online fault location on AC cables in underground transmission systems using screen currents

    Jensen, Christian Flytkjær; Nanayakkara, O.M.K.K; Rajapakse, Athula;

    This paper studies online travelling wave methods for fault location on a crossbonded cable system using screen currents. During the construction of the electrical connection to the 400 MW off shore wind farm Anholt, it was possible to perform measurements on a 38.4 km crossbonded cable system. At...... coils if the screen currents contain the necessary information for accurate fault location. In this paper, this is examined by analysis of field measurements and through a study of simulations. The wavelet transform and visual inspection methods are used and the accuracy is compared. Field measurements...

  3. Induction Motor Control through AC/DC/AC Converters

    Elfadili, Abderrahim; Giri, Fouad; Ouadi, Hamid; El Magri, Abdelmounime; Dugard, Luc; Abouloifa, Abdelmajid

    2010-01-01

    We consider the problem of controlling inductions motors driven through AC/DC rectifiers and DC/AC inverters. The control objectives are threefold: (i) forcing the motor speed to track a reference signal, (ii) regulating the DC Link voltage, (iii) assuring a satisfactory power factor correction (PFC) with respect to the power supply net. First, a nonlinear model of the whole controlled system is developed in the Park-coordinates. Then, a nonlinear multi-loop controller is synthesized using th...

  4. Online Location of Faults on AC Cables in Underground Transmission Systems

    Jensen, Christian Flytkjær

    deviations in the parameters of the OHL will result in large errors for fault location in the cable section. Field measurements showing the effect of short circuits on crossbonded systems conducted on parts of the electrical connection to the Anholt offshore wind farm are performed. The purpose is to examine...... whether neural networks can be trained using data from state-of-theart cable models to predict and estimate the fault location on crossbonded cables. Numerous measurements of different short circuits are carried out and it is concluded that the state-ofthe-art models predict general behaviour of the...... crossbonded system under fault conditions well, but the accuracy of the calculated impedance is low for fault location purposes. The neural networks can therefore not be trained and no impedance-based fault location method can be used for crossbonded cables or hybrid lines. The use of travelling wave...

  5. Modal analysis of AC quadrupole magnet system for CSNS/RCS

    The quadrupole magnet of the China Spallation Neutron Source (CSNS) Rapid-cycling Synchrotron (RCS) is operated at a 25 Hz sinusoidal alternating current which causes severe vibration. The vibration will influence the long-term safety and reliable operation of the quadrupole magnet. By taking the quadrupole magnet and girder as specific model system, a method for analyzing and studying the dynamic characteristic of the system is put forward by combining theoretical calculation with experimental testing. The theoretical modal analysis results coincide with the experimental testing results. It shows that the dynamic characteristic parameters of the structure can be obtained by modal analysis which will provide a theoretical basis for the further study and the magnet girder optimal design of CSNS/RCS. (authors)

  6. AC Power Routing System in Home Based on Demand and Supply Utilizing Distributed Power Sources

    Takashi Hikihara

    2011-04-01

    Full Text Available To help reduce consumption of fossil fuels, renewable, natural and distributed power sources are being adopted. These alternative energy sources inevitably show fluctuations in the amount of output power, frequency, and voltage. The suppression of such fluctuations is a key issue to avoid disturbances in power grids. A similar situation arises as far as the regulation of in-home power flow is concerned. We focus on the quality of supplied and demanded power in particular. In this paper, an in-home power distribution system based on information of power is proposed. The system is developed in order to integrate power dispatch and communication. The experimental results show the feasibility of new flexible and efficient power management approaches.

  7. Novel AC Side P&O Maximum Power transfer control for Grid Connected Photovoltaic Systems

    Hanif, Mohamed Moin; Basu, Malabika; Gaughan, Kevin

    2010-01-01

    Grid connected Photovoltaic inverters can convert PV energy into electricity with very high efficiencies. Power from the PV panels fluctuates depending on various weather conditions. PV inverters usually include a maximum power point tracker (MPPT) to track this varying power, in order to transfer all the available power to the grid efficiently. Control of power transferred to the grid along with the MPPT plays a crucial role in determining the efficiency of a PV system. This paper discusses ...

  8. Ant colony system (ACS with hybrid local search to solve vehicle routing problems

    Suphan Sodsoon

    2016-02-01

    Full Text Available This research applied an Ant Colony System algorithm with a Hybrid Local Search to solve Vehicle Routing Problems (VRP from a single depot when the customers’ requirements are known. VRP is an NP-hard optimization problem and has usually been successfully solved optimum by heuristics. A fleet of vehicles of a specific capacity are used to serve a number of customers at minimum cost, without violating the constraints of vehicle capacity. There are meta-heuristic approaches to solve these problems, such as Simulated Annealing, Genetic Algorithm, Tabu Search and the Ant Colony System algorithm. In this case a hybrid local search was used (Cross-Exchange, Or-Opt and 2-Opt algorithm with an Ant Colony System algorithm. The Experimental Design was tested on 7 various problems from the data set online in the OR-Library. There are five different problems in which customers are randomly distributed with the depot in an approximately central location. The customers were grouped into clusters. The results are evaluated in terms of optimal routes using optimal distances. The experimental results are compared with those obtained from meta-heuristics and they show that the proposed method outperforms six meta-heuristics in the literature.

  9. Analysis and implementation of power management and control strategy for six-phase multilevel ac drive system in fault condition

    Sanjeevikumar Padmanaban

    2016-03-01

    Full Text Available This research article exploits the power management algorithm in post-fault conditions for a six-phase (quad multilevel inverter. The drive circuit consists of four 2-level, three-phase voltage source inverter (VSI supplying a six-phase open-end windings motor or/impedance load, with circumstantial failure of one VSI investigated. A simplified level-shifted pulse-width modulation (PWM algorithm is developed to modulate each couple of three-phase VSI as 3-level output voltage generators in normal operation. The total power of the whole ac drive is shared equally among the four isolated DC sources. The developed post-fault algorithm is applied when there is a fault by one VSI and the load is fed from the remaining three healthy VSIs. In faulty conditions the multilevel outputs are reduced from 3-level to 2-level, but still the system propagates with degraded power. Numerical simulation modelling and experimental tests have been carried out with proposed post-fault control algorithm with three-phase open-end (asymmetrical induction motor/R-L impedance load. A complete set of simulation and experimental results provided in this paper shows close agreement with the developed theoretical background.

  10. Optimization of AC Dipole Parameters for the Mu2e Extinction System

    Prebys, E.; /Fermilab

    2012-05-01

    The Mu2e experiment is being planned at Fermilab to measure the rate for muons to convert to electrons in the field of an atomic nucleus with unprecedented precision. This experiment uses an 8 GeV primary proton beam consisting of short ({approx}200 nsec FW) bunches, separated by 1.7 {mu}sec. It is vital that out-of-bunch beam be suppressed at the level of 10{sup -10} or less. This poster describes the parametric analysis which was done to determine the optimum harmonics and magnet specifications for this system, as well as the implications for the beam line optics.

  11. AC field measurements of Fermilab Booster correctors using a rotating coil system

    The first prototype of a new corrector package for the Fermilab Booster Synchrotron is presently in production. This water-cooled package includes normal and skew dipole, quadrupole and sextupole elements to control orbit, tune and chromaticity of the beam over the full range of Booster energies (0.4-8 GeV). These correctors operate at the 15 Hz excitation cycle of the main synchrotron magnets, but must also make more rapid excursions, in some cases even switching polarity in approximately 1 ms at transition crossing. To measure the dynamic field changes during operation, a new method based on a relatively slow rotating coil system is proposed. The method pieces together the measured voltages from successive current cycles to reconstruct the field harmonics. This paper describes the method and presents initial field quality measurements from a Tevatron corrector

  12. Hermetisk AC-Krets

    Hirsch, Carl; Smirnoff, Alexander

    2007-01-01

    Under sex månader våren 2007 har ett samarbete mellan Volvo Lastvagnar och två studenter från KTH, inriktning Integrerad produktutveckling vid institutionen för maskinkonstruktion, pågått i form av ett examensarbete på 20 poäng. Dagens AC-system i Volvos lastbilar avger 20-40 g/år av köldmediet R134a som är en kraftfull växthusgas. Detta sker främst genom diffusion via slangar och tätningsmaterial. Syftet med detta examensarbete är att ta fram förslag på tekniska lösningar på ett nytt AC-syst...

  13. Comparative study between PI, RST and sliding mode controllers of a DFIG supplied by an AC-AC converter for wind energy conversion system

    Ahmed Bourouina

    2015-12-01

    Full Text Available This paper deals with a variable speed device to produce electrical energy on a power network, based on a doubly-fed induction generator (DFIG supplied by a direct matrix converter used in wind energy conversion systems. In the first place, we carried out briefly a study of modelling on the whole system. In order to control the power flowing between the stator of the DFIG and the power network, a control law is synthesized using three types of controllers: PI, RST and sliding mode controllers. Their respective performances are compared in terms of power reference tracking, response to sudden speed variations, sensitivity to perturbations and robustness against machine parameters variations.

  14. Biological and Biomechanical Evaluation of the Ligament Advanced Reinforcement System (LARS AC) in a Sheep Model of Anterior Cruciate Ligament Replacement: A 3-Month and 12-Month Study

    Viateau, Véronique; MANASSERO, Mathieu; ANAGOSTOU, Fani; GUERARD, Sandra; Mitton, David; Migonney, Véronique

    2013-01-01

    PurposeThe purposes of this study were to assess tissue ingrowth within the Ligament Advanced Reinforcement System (LARS) artificial ligament (LARS AC; LARS, Arc sur Tille, France) and to study the biomechanical characteristics of the reconstructed knees in a sheep model of anterior cruciate ligament (ACL) replacement.MethodsTwenty-five female sheep underwent excision of the proximal third of the left ACL and intra-articular joint stabilization with a 44-strand polyethylene terephthalate liga...

  15. The HST/ACS Coma Cluster Survey IV. Intergalactic Globular Clusters and the Massive Globular Cluster System at the Core of the Coma Galaxy Cluster

    Peng, Eric W.; Ferguson, Henry C.; Goudfrooij, Paul; Hammer, Derek; Lucey, John R.; Marzke, ; Ronald O.; Puzia, Thomas H.; Carter, David; Balcells, Marc; Bridges, Terry; Chiboucas, Kristin; del Burgo, Carlos; Graham, Alister W.; Guzman, Rafael; Hudson, Michael J.

    2011-01-01

    Intracluster stellar populations are a natural result of tidal interactions in galaxy clusters. Measuring these populations is difficult, but important for understanding the assembly of the most massive galaxies. The Coma cluster is one of the nearest truly massive galaxy clusters, and is host to a correspondingly large system of globular clusters (GCs). We use imaging from the HST/ACS Coma Cluster Survey to present the first definitive detection of a large population of intracluster GCs (IGC...

  16. Identification of an Unknown Assistant Blowing Agent in AC Blowing System%一种助发泡剂的鉴定

    何文绚; Robert Shanks

    2004-01-01

    In this study, TLC was used to separate and purify the unknown assistant blowing agent in AC blowing system. After that, FTIR-Microscope was used to indicate the functional group in the uncommon unknown compound. Through combination of FTIR analysis, elemental analysis and other physical and chemical analysis, the molecular structure of unknown was deduced. Finally by explaining mass spectra of the unknown compounds, the molecular structure of unknown was further confirmed.

  17. Reliability Improvement of Ground Fault Protection System Using an S-Type Horn Attachment Gap in AC Feeding System

    Ajiki, Kohji; Morimoto, Hiroaki; Shimokawa, Fumiyuki; Sakai, Shinya; Sasaki, Kazuomi; Sato, Ryogo

    Contact wires used in feeding system for electric railroad are insulated by insulators. However, insulation of an insulator sometimes breaks down by surface dirt of an insulator and contact with a bird. The insulator breakdown derives a ground fault in feeding system. Ground fault will cause a human electric shock and a destruction of low voltage electric equipment. In order to prevent the damage by ground fault, an S-type horn has been applicable as equipped on insulators of negative feeder and protective wire until present. However, a concrete pole breaks down at the time of the ground fault because a spark-over voltage of the S-type horn is higher than a breakdown voltage of a concrete pole. Farther, the S-type horn installed in the steel tube pole does not discharge a case, because the earth resistance of a steel tube pole is very small. We assumed that we could solve these troubles by changing the power frequency spark-over voltage of the S-type horn from 12kV to 3kV. Accordingly, we developed an attachment gap that should be used to change the power frequency spark-over voltage of the S-type horn from 12kV to 3kV. The attachment gap consists of a gas gap arrester and a zinc oxide element. By the dynamic current test and the artificial ground fault test, we confirmed that the attachment gap in the S-type horn could prevent a trouble at the time of the ground fault.

  18. Some Aspects of the Use of a Cryogenic Ally-Cooled Primary Windings System for an a.c. MHD Generator

    The performance of an a.c. MHD converter depends upon the magnetic Reynolds number of the secondary (liquid metal) and the performance of the primary magnetic circuit, i.e. the windings system which produces the magnetic travelling wave. In the known a.c. MHD configuration the windings system consists of a conventional multiphase system such as that used for the conventional asynchronous machine. But unlike these, the gap between iron cores is increased to the channel height which is 20, 30 or more times greater. Therefore the reactance of the machine, and hence the inductive component of the current, becomes large. That causes an insufficiently small value of the power factor (cos ∅) of the machine. In order to compensate, the current density of the primary windings must be increased 20 to 30 times in comparison to that in the conventional asynchronous machine. This is only possible with the use of a cryogenically- cooled primary winding system. The specific resistance of pure metals (e.g. copper, aluminium or sodium) is reduced drastically at low temperatures, allowing of a drastic increase in the ampere-turn density of the machine without increasing the resistance of the windings above permissible limits. Two configurations of cryogenically-cooled windings systems for a.c. MHD converters are proposed. One uses a liquid nitrogen cooling system and the second a liquid hydrogen cooling system. Real machine data are considered and the characteristics of the converter are given, mainly by considering the circle diagram of the machine (current vector as a function of slip s). An a.c. MHD converter, based on the first winding configuration, cryogenically cooled with liquid nitrogen, and working with mercury, is now running. The performance and the technological problems are being studied. The machine details are reported. Measurements of flow velocity, pressure drop along the MHD channel, temperature of mercury, losses in mercury, power flow between working fluid and

  19. ACAC Converters for UPS

    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.

  20. Ac Hybrid Charge Controller

    Shalini S. Durgam

    2015-03-01

    Full Text Available One of the primary needs for socio-economic development in any nation in the world is the provision of reliable electricity supply systems with lower carbon footprint levels. The purpose of this work is the development of a hybrid Power system that harnesses the renewable energy in sun and electricity to generate electricity. The working model can able to run on dual mode- solar and electricity. It can also be driven independently either by solar or electricity. The battery can be charge from solar panel (40W or by power supply. The household single phase A.C. power supply of 230V is converted into 12V D.C. using step down transformer and rectifying circuit. The working model can achieve energy saving, low carbon emission, environmental protection for the upcoming future of human life.

  1. Analysis of Reactive Power Compensation in UHV AC Transmission System%特高压交流输电系统无功补偿策略分析

    李静雅

    2015-01-01

    Ultra high voltage transmission system with a high rechargeable power,long transmission line characteris-tics,and thus faces a serious problem of reactive power balance,in order to ensure the effect of reactive power compensa-tion in UHV transmission system,analyzed the reactive power compensation strategy in UHV AC transmission system in this paper.%特高压输电系统具有充电功率大,输电线路长的特点,但面临严重的无功平衡问题。为了保证特高压输电系统的无功补偿效果,文中分析了特高压交流输电系统无功补偿策略。

  2. Analysis of Reactive Power Compensation in UHV AC Transmission System%特高压交流输电系统无功补偿策略分析

    李静雅

    2015-01-01

    特高压输电系统具有充电功率大,输电线路长的特点,但面临严重的无功平衡问题。为了保证特高压输电系统的无功补偿效果,文中分析了特高压交流输电系统无功补偿策略。%Ultra high voltage transmission system with a high rechargeable power,long transmission line characteris-tics,and thus faces a serious problem of reactive power balance,in order to ensure the effect of reactive power compensa-tion in UHV transmission system,analyzed the reactive power compensation strategy in UHV AC transmission system in this paper.

  3. Operating Characteristics Test System for AC/DC Contactor%交直流接触器动作特性测试系统

    林文贵; 许志红

    2014-01-01

    The operating characteristics test system of AC/DC contactor was introduced.It achieves phase selection in the closing and opening course of contactor.Keyence laser displacement sensor is used to achieve the test of displacement of contact and iron core changing over time.Moreover,the sound signal making in the closing course of contactor by electret microphone is captured.The voltage,current of coil and main circuit with three-phase contacts are obtained.All signals mentioned above transmitting to PC based on data-acquisition,the system achieves data processing,automatically measuring and saving.The test system provides technical support for contactor studying and simulation,control strategy verifying of AC/DC contactor.It is of theoretical and practical significance in the design and development of AC/DC contactor.%介绍了一套交/直流接触器动作特性测试系统。系统实现了对交流接触器的选相分/合闸控制,采用激光位移传感器实现触头与铁心动态位移测试,驻极体传声器采集接触器闭合过程声音信号,霍尔传感器采集线圈回路和三相触头回路电压电流信号;同时使用数据采集卡将信号采集到上位机,完成数据的处理分析、自动测量、数据存储等功能。系统为交直流接触器的仿真研究、控制方案等提供技术支持,对提高接触器的设计与开发水平具有理论和实际意义。

  4. Rapid cycling synchrotron magnet with separate ac and dc circuit

    In present rapid cycling synchrotron magnets ac and dc currents flow in the same coil to give the desired field. The circuit reactance is made zero at dc and the operating frequency by running the magnet in series with an external parallel resonant LC current. We propose to return the ac flux in a gap next to the synchrotron. The dc coil encloses the ac magnetic circuit and thus links no ac flux. A shorted turn between the dc coil and ac flux enhances the separation of the two circuits. Several interesting developments are possible. The dc coil could be a stable superconductor to save power. The ac flux return gap could be identical with the synchrotron gap and contain a second synchrotron. This would double the output of the system. If the return flux gap were used for a booster, the ac coil power could be greatly reduced or radiation hardening of the ac coil could be simplified

  5. THE ACS VIRGO CLUSTER SURVEY. XVII. THE SPATIAL ALIGNMENT OF GLOBULAR CLUSTER SYSTEMS WITH EARLY-TYPE HOST GALAXIES

    Wang Qiushi; Peng, Eric W. [Department of Astronomy, Peking University, Beijing 100871 (China); Blakeslee, John P.; Cote, Patrick; Ferrarese, Laura [Herzberg Institute of Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Jordan, Andres [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Mei, Simona [University of Paris 7 Denis Diderot, F-75205 Paris Cedex 13 (France); West, Michael J., E-mail: peng@pku.edu.cn [Maria Mitchell Observatory, 4 Vestal Street, Nantucket, MA 02554 (United States)

    2013-06-01

    We study the azimuthal distribution of globular clusters (GCs) in early-type galaxies and compare them to their host galaxies using data from the ACS Virgo Cluster Survey. We find that in host galaxies with visible elongation ({epsilon} > 0.2) and intermediate to high luminosities (M{sub z} < -19), the GCs are preferentially aligned along the major axis of the stellar light. The red (metal-rich) GC subpopulations show strong alignment with the major axis of the host galaxy, which supports the notion that these GCs are associated with metal-rich field stars. The metal-rich GCs in lenticular galaxies show signs of being more strongly associated with disks rather than bulges. Surprisingly, we also find that the blue (metal-poor) GCs can also show the same correlation. If the metal-poor GCs are part of the early formation of the halo and built up through mergers, then our results support a picture where halo formation and merging occur anisotropically, and that the present-day major axis is an indicator of the preferred merging axis.

  6. Comparison of a synergetic battery pack drive system to a pulse width modulated AC induction motor drive for an electric vehicle

    Davis, A.; Salameh, Z.M. [Univ. of Massachusetts, Lowell, MA (United States). Dept. of Electrical Engineering; Eaves, S.S. [Eaves Devices, Charlestown, RI (United States)

    1999-06-01

    A new battery configuration technique and accompanying control circuitry, termed a Synergetic Battery Pack (SBP), is designed to work with Lithium batteries, and can be used as both an inverter for an electric vehicle AC induction motor drive and as a battery charger. In this paper, the performance of a Synergetic Battery Pack during motor drive operation is compared via computer simulation with a conventional motor drive which uses sinusoidal pulse width modulation (SPWM) to determine its effectiveness as a motor drive. The study showed that the drive efficiency was compatible with the conventional system, and offered a significant advantage in the lower frequency operating ranges. The voltage total harmonic distortion (THD) of the SBP was significantly lower than the PWM drive output, but the current THD was slightly higher due to the shape of the harmonic spectrum. In conclusion, the SBP is an effective alternative to a conventional drive, but the real advantage lies in its battery management capabilities and charger operation.

  7. AcEST: DK950971 [AcEST

    Full Text Available optera acutorost... 37 0.66 tr|B1ACS6|B1ACS6_BALBN DMP1 (Fragment) OS=Balaenoptera ...bonaerens... 37 0.66 tr|B1ACS5|B1ACS5_BALED DMP1 (Fragment) OS=Balaenoptera edeni... GN=... 37 0.66 tr|B1ACS4|B1ACS4_BALBO DMP1 (Fragment) OS=Balaenoptera borealis ... 37 0.66 tr|B1ACS3|B1ACS3..._BALMU DMP1 (Fragment) OS=Balaenoptera musculus ... 37 0.86 tr|B1ACS1|B1ACS1_MEGNO DMP1 (Fragment) OS=Megapt...1ACS2_BALPH DMP1 (Fragment) OS=Balaenoptera physalus ... 37 1.1 tr|B1ACT6|B1ACT6_MESPE DMP1 (Fragment) OS=Me

  8. AC1 Wing

    Adrian DOBRE

    2010-03-01

    Full Text Available The AC1 wing replaces the old wing of the wind tunnel model AEROTAXI, which has been made at scale 1:9. The new wing is part of CESAR program and improves the aerodynamic characteristics of the old one. The geometry of the whole wing was given by FOI Sweden and position of AC1 wing must coincide with the structure of the AEROTAXI model.

  9. AC1 Wing

    Adrian DOBRE

    2010-01-01

    The AC1 wing replaces the old wing of the wind tunnel model AEROTAXI, which has been made at scale 1:9. The new wing is part of CESAR program and improves the aerodynamic characteristics of the old one. The geometry of the whole wing was given by FOI Sweden and position of AC1 wing must coincide with the structure of the AEROTAXI model.

  10. Damping effects of Supplementary Control Signals for Enhancement of Transient Stability in AC-DC Power Systems

    Uma Vani M; Dr. Ramana Rao P.V.

    2010-01-01

    This paper discusses the impact of HVDC on Power System Stability and proposes a novel controlmechanism to augment the system angle stability. The effectiveness of the proposed controller is demonstrated by asingle machine-infinite bus system example. The performance of this controller, in comparison to the conventionalP and P-I controllers, is found to be very effective as a supplementary PID controller in damping generator rotoroscillations. The supplementary controls using signals derived ...

  11. Development and implementation of a 2x25kV AC bivoltage traction system simulator for high speed railways

    Plakhova, Mariia

    2015-01-01

    This thesis was focused on the power flow and power system simulation, therefore, the complex train model has not been built and trains are represented as non-linear power sources. The objective of this thesis was to develop the mathematical model of the bivoltage power system for the traction purpose and solve it, applying different numerical technics

  12. Regulation of Dynamical Systems to Optimal Solutions of Semidefinite Programs: Algorithms and Applications to AC Optimal Power Flow

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

    2014-01-01

    This paper considers a collection of networked nonlinear dynamical systems, and addresses the synthesis of feedback controllers that seek optimal operating points corresponding to the solution of network-wide constrained optimization problems. Particular emphasis is placed on the solution of semidefinite programs (SDPs). The design of the feedback controller is grounded on a dual epsilon-subgradient approach, with the dual iterates utilized to dynamically update the dynamical-system reference...

  13. A High Swithching Frequency IGBT PWM Rectifier/Inverter System For AC Motor Drives Operating From Single Phase Supply

    Thiyagarajah, K; Ranganathan, VT; Iyenger, Ramakrishna BS

    1990-01-01

    A pulse width modulated (PWM) rectifier/inverter system using insulated gate bipolar transistors (IGBT's), capable of switching at $20 kH_z$ is reported. The base drive circuit for the IGBT, incorporating short-circuit protection, is presented. The inverter uses an Undeland snubber together with a simple energy recovery circuit, which ensures reliable and efficient operation even for $20 kH_z$ switching. The front end for the system is a regenerative single phase full bridge IGBT inverter alo...

  14. Selection of topologies for the PHOTONERGY{sup TM} project. Optimised design and control of inverter for photovoltaic systems: the AC-module

    Baekhoej Kjaer, S.

    2002-06-01

    The PHOTONERGY{sup TM} project (also known as the former 'SolcelleInverter' project) is by this report carried into its third stage; the selection of a suitable topology for the AC-Module inverter. The selection of a suitable topology is based on State-Of-The-Art analysis a specifications and a comparison of four grid-tied inverters and nine dc/dc converters. This implies 23 possible combinations, from which nine is investigated with respect to efficiency in six working points, the number of components and to some extent also the rating of the components. The conclusion is that the target of a European efficiency of 93.7% is hard to achieve. But four of the examined, and two newly discovered, inverters are recommended for a further examination by means of estimations, calculations and simulations of: cost, complexity, robustness, efficiency and mass-production. The system-layout is also examined. The first layout implies that the PV-Module and the inverter is integrated into one unit and the second layout involves that the inverter is placed indoor. The layouts are compared with respect to cable-losses, enclosure demanding and lifetime. The conclusion is somehow ambiguous and a further investigation should be initiated in order to get a clear result. (au)

  15. A Research Review on the Transmission System of AC Servo Motor Direct Drive Hydraulic Press%交流伺服电机直驱液压机传动系统研究综述

    范淑琴; 赵升吨; 陈超; 杨建辉

    2015-01-01

    交流伺服电机直驱液压机相比传统液压机,具有低速锻冲、快速空程向下及快速回程的特点,其交流伺服电机直驱的传动方式可有效减少滑块上行和下行的时间,大大提高液压机工作速度。介绍了国内外交流伺服电机直驱液压机传动系统的研究现状,提出了一种无油泵交流伺服电机直驱新型液压机传动方式,介绍了该新型液压机传动系统的构成及工作原理,并提出了研制该无油泵交流伺服电机直驱新型液压机所需要解决的科学问题。%Compared to the traditional hydraulic press, Ac servo motor direct drive hydraulic press has the characteris-tics including rapid falling, slow forging and fast return. The transmission mode of AC servo motor direct drive can effec-tively reduce both the falling time and rising time of the slider, and greatly improve the working speed of hydraulic press. The research status of transmission system of Ac servo motor direct drive hydraulic press are introduced in this paper, and the transmission model of a new type AC servo motor direct drive hydraulic press without oil pump is proposed. Both the composition and working principle of the transmission system of the new type hydraulic presser are introduced, and the sci-entific problems about the new type AC servo motor direct drive hydraulic press without oil pump are put forward.

  16. High voltage AC/AC electrochemical capacitor operating at low temperature in salt aqueous electrolyte

    Abbas, Qamar; Béguin, François

    2016-06-01

    We demonstrate that an activated carbon (AC)-based electrochemical capacitor implementing aqueous lithium sulfate electrolyte in 7:3 vol:vol water/methanol mixture can operate down to -40 °C with good electrochemical performance. Three-electrode cell investigations show that the faradaic contributions related with hydrogen chemisorption in the negative AC electrode are thermodynamically unfavored at -40 °C, enabling the system to work as a typical electrical double-layer (EDL) capacitor. After prolonged floating of the AC/AC capacitor at 1.6 V and -40°C, the capacitance, equivalent series resistance and efficiency remain constant, demonstrating the absence of ageing related with side redox reactions at this temperature. Interestingly, when temperature is increased back to 24 °C, the redox behavior due to hydrogen storage reappears and the system behaves as a freshly prepared one.

  17. AC/RF Superconductivity

    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.

  18. AC/RF Superconductivity

    Ciovati, G.

    2015-01-01

    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.

  19. Performance of Frequency Division Multiplexing Readout System for AC-Biased Transition-Edge Sensor X-ray Microcalorimeters

    Yamamoto, R.; Sakai, K.; Takei, Y.; Yamasaki, N. Y.; Mitsuda, K.

    2014-08-01

    Frequency division multiplexing (FDM) is a promising approach to read out a large format transition-edge sensor (TES) array for future astrophysical missions. We constructed a four channel FDM readout system using baseband feedback in the MHz band. We demonstrated the principle of our FDM method with an actual TES array, a multiplexing SQUID and LC band-pass filters under 100 mK. The resonant frequencies of LC filters were consistent with the design value with an accuracy of better than 3 %. We successfully obtained X-ray pulses from two TESs simultaneously but the energy resolution was degraded to about 100 eV at 5.9 keV and crosstalk effects were observed. The origin of the crosstalk effects is investigated by modified setups. Based on comparative experiments and numerical calculations, we conclude that the non-linearity of the SQUID is the cause of some of the crosstalk effects. Unlike the regular crosstalk effect from the adjoining channels, the crosstalk effect due to non-linearity observed in this paper occurs in all channels. Solving these problems will help us to obtain FDM readout with sufficient energy resolution.

  20. Adaptive Nonlinear Control of Induction Motors through AC/DC/AC Converters

    Elfadili, Abderrahim; Giri, Fouad; El Magri, Abdelmounime; Dugard, Luc; Chaoui, Fatima Zara

    2012-01-01

    The problem of controlling induction motors, together with associated AC/DC rectifiers and DC/AC inverters, is addressed. The control objectives are threefold: (i) the motor speed should track any reference signal despite mechanical parameter uncertainties and variations; (ii) the DC Link voltage must be tightly regulated; (iii) the power factor correction (PFC) w.r.t. the power supply net must be performed in a satisfactory way. First, a nonlinear model of the whole controlled system is deve...

  1. Robust control of synchronous motors through AC/DC/AC converters

    El Magri, Abdelmounime; Giri, Fouad; Abouloifa, Abdelmajid; Chaoui, Fatima Zara

    2010-01-01

    The problem of controlling synchronous motors, driven through AC/DC rectifiers and DC/AC inverters is addressed. The control objectives are three fold: (i) forcing the motor speed to track a varying reference signal in presence of motor parameter uncertainties;(ii) regulating the DC Link voltage; (iii )assuring a satisfactory power factor correction (PFC) with respect to the power supply net .First, a nonlinear model of the whole controlled system is developed in the Park-coordinates. Then, a...

  2. Precision rectifier detectors for ac resistance bridge measurements with application to temperature control systems for irradiation creep experiments

    Duncan, M. G.

    1977-05-01

    The suitability of several temperature measurement schemes for an irradiation creep experiment is examined. It is found that the specimen resistance can be used to measure and control the sample temperature if compensated for resistance drift due to radiation and annealing effects. A modified Kelvin bridge is presented that allows compensation for resistance drift by periodically checking the sample resistance at a controlled ambient temperature. A new phase-insensitive method for detecting the bridge error signals is presented. The phase-insensitive detector is formed by averaging the magnitude of two bridge voltages. Although this method is substantially less sensitive to stray reactances in the bridge than conventional phase-sensitive detectors, it is sensitive to gain stability and linearity of the rectifier circuits. Accuracy limitations of rectifier circuits are examined both theoretically and experimentally in great detail. Both hand analyses and computer simulations of rectifier errors are presented. Finally, the design of a temperature control system based on sample resistance measurement is presented. The prototype is shown to control a 316 stainless steel sample to within a 0.15/sup 0/C short term (10 sec) and a 0.03/sup 0/C long term (10 min) standard deviation at temperatures between 150 and 700/sup 0/C. The phase-insensitive detector typically contributes less than 10 ppM peak resistance measurement error (0.04/sup 0/C at 700/sup 0/C for 316 stainless steel or 0.005/sup 0/C at 150/sup 0/C for zirconium).

  3. THE HST/ACS COMA CLUSTER SURVEY. IV. INTERGALACTIC GLOBULAR CLUSTERS AND THE MASSIVE GLOBULAR CLUSTER SYSTEM AT THE CORE OF THE COMA GALAXY CLUSTER

    Intracluster stellar populations are a natural result of tidal interactions in galaxy clusters. Measuring these populations is difficult, but important for understanding the assembly of the most massive galaxies. The Coma cluster of galaxies is one of the nearest truly massive galaxy clusters and is host to a correspondingly large system of globular clusters (GCs). We use imaging from the HST/ACS Coma Cluster Survey to present the first definitive detection of a large population of intracluster GCs (IGCs) that fills the Coma cluster core and is not associated with individual galaxies. The GC surface density profile around the central massive elliptical galaxy, NGC 4874, is dominated at large radii by a population of IGCs that extend to the limit of our data (R +4000-5000 (systematic) IGCs out to this radius, and that they make up ∼70% of the central GC system, making this the largest GC system in the nearby universe. Even including the GC systems of other cluster galaxies, the IGCs still make up ∼30%-45% of the GCs in the cluster core. Observational limits from previous studies of the intracluster light (ICL) suggest that the IGC population has a high specific frequency. If the IGC population has a specific frequency similar to high-SN dwarf galaxies, then the ICL has a mean surface brightness of μV ∼ 27 mag arcsec-2 and a total stellar mass of roughly 1012 Msun within the cluster core. The ICL makes up approximately half of the stellar luminosity and one-third of the stellar mass of the central (NGC 4874+ICL) system. The color distribution of the IGC population is bimodal, with blue, metal-poor GCs outnumbering red, metal-rich GCs by a ratio of 4:1. The inner GCs associated with NGC 4874 also have a bimodal distribution in color, but with a redder metal-poor population. The fraction of red IGCs (20%), and the red color of those GCs, implies that IGCs can originate from the halos of relatively massive, L* galaxies, and not solely from the disruption of dwarf

  4. Loss of vital ac power and the residual heat removal system during mid-loop operations at Vogtle Unit 1 on March 20, 1990

    On March 20, 1990, the Vogtle Electric Generating Plant Unit 1, located in Burke County, Georgia, about 25 miles southeast of Augusta, experienced a loss of all safety (vital) ac power. The plant was in cold shutdown with reactor coolant level lowered to ''mid-loop'' for various maintenance tasks. Both the containment building personnel hatch and equipment hatch were open. One emergency diesel generator and one reserve auxiliary transformer were out of service for maintenance, with the remaining reserve auxiliary transformer supplying both Unit 1 safety buses. A truck in the low voltage switchyard backed into the support column for an offsite power feed to the reserve auxiliary transformer which was supplying safety power. The insulator broke, a phase-to-ground fault occurred, and the feeder circuit breakers for the safety buses opened. The operable emergency diesel generator started automatically because of the undervoltage condition on the safety bus, but tripped off after about 1 minute. About 20 minutes later the diesel generator load sequencer was reset, causing the diesel generator to start a second time. The diesel generator operated for about 1 minute, and tripped off. The diesel generator was restarted in the manual emergency mode 36 minutes after the loss of power. The generator remained on line and provided power to its safety bus. During the 36 minutes without safety bus power, the reactor coolant system temperature rose from about 90 degree F to 136 degree F. This report documents the results of an Incident Investigation Team sent to Vogtle by the Executive Director for Operations of the US Nuclear Regulatory Commission to determine what happened, identify the probable causes, and make appropriate findings and conclusions. 79 figs., 16 tabs

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

    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.

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

    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.

  7. ACS air bearing test-bed design

    Glitt, Sascha

    2010-01-01

    This thesis is about the construction and design of a new air bearing test-bed to verify the programmed ACS attitude control algorithm and to validate the ACS MATLAB/SimuLink¬ model of NPSAT1, the second small satellite currently under development at the Naval Postgraduate School Space Systems Academic Group. The software was already verified and validated using a comparable air bearing test-bed. But due to changes in hardware from commercial magnetic torque rods to custom, NPS-built, magneti...

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

    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.

  9. Titanium Aluminum Nitride Films Deposited by AC Reactive Magnetron Sputtering: Study of Positioning Effect in an Inverted Cylindrical Magnetron Sputtering System

    Vandross, George Clinton, II

    TiAlN films were deposited on glass substrates by AC magnetron sputtering at 2 kW with constant Argon and Nitrogen gas flow rates to study the effects of positioning on the deposited films. The deposition system used was an ICM-10 IsoFlux cylindrical magnetron sputtering chamber. The samples were placed in different positions and tilts with respect to the location of the Titanium and Aluminum targets in the chamber. It was found that with change in position and application of tilts, deposited films acquired different physical and chemical properties. It is believed that the differences in these properties were caused by to the change in the incident angle of bombardment of the samples, and the change in surface areas of the samples presented to the targets at each location. As related to the physical traits of the samples, analysis using Scanning Electron Microscopy of the samples displayed variations in the topography, where differences in grain density could be noted as well as structure formations. The chemical properties were also noted to be affected by the variation of tilt and position applied to the sample. X-ray Diffraction Spectroscopy analysis of the samples showed the intensity of the TiAlN characteristic peak of the samples to differ from sample to sample. Results from the XRD analysis of this work showed a 157% and 176% increase in peak intensity of the 0° tilt sample of the Bottom Plate from the 45° tilt sample and 60° tilt sample respectively of the same plate. The results from the XRD analysis of this work also showed a 74% and 151% increase of the peak intensity for the 0° tilt sample of the Middle Plate when compared to the 45° tilt sample and 60° tilt sample respectively of the same plate. Whereas results for this work showed a 54% and 41% decrease in peak intensity of the 0° tilt sample of the Top Plate from the 45° tilt sample and 60° tilt sample respectively of the same plate. Energy Dispersive X-ray Spectroscopy was also performed

  10. High performance AC drives

    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

  11. Superconducting ac cable

    The components of a superconducting 110 kV ac cable for power ratings >= 2000 MVA have been developed. The cable design especially considered was of the semiflexible type, with a rigid cryogenic envelope and flexible hollow coaxial cable cores pulled into the former. The cable core consists of spirally wound Nb-Al composite wires and a HDPE-tape wrapped electrical insulation. A 35 m long single phase test cable with full load terminations for 110 kV and 10 kA was constructed and successfully tested. The results obtained prove the technical feasibility and capability of our cable design. (orig.)

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

    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.

  13. AC power generation from microbial fuel cells

    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.

  14. Advanced DC/AC inverters applications in renewable energy

    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,

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

    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. PMID:26946374

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

    Oliveira, J. G.; Schettino, H.; Gama, V; Carvalho, R.; H. Bernhoff

    2012-01-01

    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...

  17. AcEST: BP920072 [AcEST

    Full Text Available YMU001_000132_F11 525 Adiantum capillus-veneris mRNA. clone: YMU001_000132_F11. BP920072 - Show ... YGMYGEGEKALETFADMEKSGIVPDSVVFIAII 617 Query: 139 NACSR SCLFHECHSYFEAMSTHHGIVPCLEHHSCVV 32 ACS S L E + FE M ... KLMTRDVVSWNTLIAGYAQVGQNEGLFCTFSDMLGQRVKPDLITFVIVLNACSR ... 125 VF+ + +D VSWN++I+GY Q G F M+ + D IT++++++ +R S ... YGVHGYGKKAIQIFEEMLANGASP 384 Query: 166 DLITFVIVLNACSR SCLFHECHSYFEAMSTHHGIVPCLEHHSCVV 32 +TFV VL ACS L E ... KLMTRDVVSWNTLIAGYAQVGQNEGLFCTFSDMLGQRVKPDLITFVIVLNACSR S 122 +VFDK R + WN L G E + + M V+ D T+ VL AC S Sbjc ...

  18. Numerical estimation of AC loss in superconductors with ripple current

    Highlights: •The loss energy density with ripple current is numerically calculated. •Irie–Yamafuji model is used for magnetic field dependence of critical current. •Calculated result of cylindrical superconductor agrees with theoretical result. •AC loss of strip superconductor becomes large at small ripple current amplitude. •Strip superconductor should be used as a form of hollow cylinder to reduce AC loss. -- Abstract: The loss energy density (AC loss) with ripple current is numerically calculated by finite element method for cylindrical and strip superconductors based on Irie–Yamafuji model in which the magnetic field dependence of the critical current density is taken into account for design of DC transmission cable system. It is confirmed that calculated result of the AC loss in the cylindrical superconductor with the ripple current agrees well with theoretical estimation which was reported in the previous work. On the contrary, the AC loss in the strip superconductor with the ripple current is obtained only by numerical calculation. It is found that the AC loss in the strip superconductor of the ripple current becomes larger than that without DC current at small ripple current amplitude, since the penetration depth of magnetic field becomes large. Therefore, it is recommended that strip superconductor is better to use as cylindrical hollow superconductor for DC transmission cable system to reduce the AC loss

  19. 基于DSP和智能功率模块的交流伺服系统硬件设计%AC Servo System Hardware Design Based on DSP and Intelligent Power Module

    刘江宁; 吴钦木; 何志琴; 张吉婷

    2012-01-01

    As the development of the microprocessor technology, power electronic technology, motor manufacturing technology and modern control theory, ac servo system used more and more widely. In this paper, we will use the TMS320F2812 as the core to design control circuit and FSBB20CH60 as the core to design power drive circuit and completed the part design of AC servo system's hardware,contains both current sampling and failure protection circuit and it with the advantage of design reasonable, structure compact, control precise and so on.%随着微处理器技术、电力电子技术、电机制造技术和现代控制理论的发展,交流伺服系统的应用越来越广.以TMS320F2812为核心设计控制电路,以FSBB20CH60为核心设计功率驱动电路,完成了包括电流采样及故障保护在内的交流伺服系统硬件部分的设计,具备了设计合理、结构紧凑和控制精确等优点.

  20. AcEST: BP920905 [AcEST

    Full Text Available EM + + D ++S L AC Sbjct: 374 NSAYKLFERMPKKNVVAWNAIISGYSQHGHPHEALALFIEMQAQGIKPDSFAIVSVLPAC 433 Query: 71 SHSSTLNDGKLIHFYILMNNFE...EM++ ++ + V + S L +C Sbjct: 255 SSERIFEKIAKKNAVSWTAMISSYNRGEFSEKALRSFSEMIKSGIEPNLVTLYSVLSSCG 314 Query: 68 HSSTLNDGKLIHFYILMNNFE...VVVMSCLKACS 69 ++ +F RRD VTW A+I GYA HG E A+ LF+ M+ EN+ + V +S L+AC+ Sbjct: 656 DSRLMFEKSLRRDFVTWNAMICGYAHHGKGEEAIQLFERMILEN...ELEKMHNKRLQEMCVSWNSIISGYVMKEQSEDAQMLFTRMME 596 Query: 122 ENVDTDGVVVMSCLKACSHSSTLNDGKLIHFYILMNNFE ...FCEADT-NVITWNAMIASYVHCEQSEKAIALFDRMVSENFKPSSITLVTLLMAC 543 Query: 71 SHSSTLNDGKLIHFYILMNNFEL 3 ++ +L G++

  1. AcEST: DK950147 [AcEST

    Full Text Available TST38A01NGRL0007_O05 706 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0007_O05. 5' end seq ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... OS=Medicago truncatula GN=MtrDRAFT_AC149576g3v2 PE ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... (Fragment) OS=Medicago truncatula GN=MtrDRAFT_AC14 ...

  2. AcEST: DK959344 [AcEST

    Full Text Available TST39A01NGRL0004_G23 714 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0004_G23. 5' end seq ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... OS=Medicago truncatula GN=MtrDRAFT_AC149576g3v2 PE ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... (Fragment) OS=Medicago truncatula GN=MtrDRAFT_AC14 ...

  3. AcEST: DK949716 [AcEST

    Full Text Available TST38A01NGRL0006_L20 613 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0006_L20. 5' end seq ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... OS=Medicago truncatula GN=MtrDRAFT_AC149576g3v2 PE ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... (Fragment) OS=Medicago truncatula GN=MtrDRAFT_AC14 ...

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

    Ahmet ALTINTAŞ

    2009-01-01

    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 abi...

  5. AC drives for industrial plants. Plant kudoyo AC drive sochi

    Miyazaki, M.; Shibata, M.; Yamada, S. (Toshiba Corp., Tokyo (Japan))

    1992-08-01

    Features and product series of AC drives for industrial plants were outlined. Configurations and features of various types of AC drives were briefly discussed which are put into market to meet various requirements for industrial plants and wide ranges of output voltage and capacity. The following product series were outlined; the power bipolar transistor inverter for 3.5-600 kVA in output capacity, IGBT inverter for AC 400 V in output voltage and 1,000 kVA or less, GTO inverter for AC 600 V and 700-2,000 kVA, and cycloconverter for AC 1,000-3,000 V and 1,000 kW-20 MW. The following subjects were outlined as current technical trends of AC drives for industrial plants; increasing in capacity of voltage-source PWM inverters, downsizing of converters through highly efficient cooling and highly dense mounting, spreading of sensorless vector controls, and development of high-voltage large-capacity PWM inverters. 6 figs., 2 tabs.

  6. Diagnostics of the Fermilab Tevatron using an AC dipole

    Miyamoto, Ryoichi; /Texas U.

    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 {approx} 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.

  7. Acúmulo de macronutrientes pela cultivar de cebola "Superex" estabelecida por semeadura direta Evaluating macronutrients accumulated in onion plants of the 'Superex' cultivar in direct seeding system

    Diego Resende de Queirós Pôrto

    2007-08-01

    Full Text Available O objetivo do trabalho foi quantificar o acúmulo de macronutrientes ao longo do ciclo da cebola, cv. "Superex", estabelecida por semeadura direta. O experimento foi conduzido na Fazenda Rio Doce, entre os municípios de Itobi e São José do Rio Pardo, SP. As amostragens de plantas foram realizadas aos 30, 50, 70, 90, 110, 130 e 150 dias após a semeadura (DAS, para determinação da matéria seca e do acúmulo dos nutrientes (N, P, K, Ca, Mg e S. Os acúmulos máximos de matéria seca da parte aérea e do bulbo foram, respectivamente, de 4,70g planta-1 e 17,86g planta-1, aos 150 DAS. A parte aérea e o bulbo contribuíram, respectivamente, com cerca de 20 e 80% na matéria seca da planta inteira ao final do ciclo. A seqüência de acúmulo dos nutrientes verificada para a cebola "Superex" foi: K>N>Ca>S>Mg>P. A planta de cebola acumulou 202,43; 31,23; 295,28; 172,42; 35,20 e 73,47mg, respectivamente, de N, P, K, Ca, Mg e S. Exportou, pelo bulbo, 67% do N, 85% do P, 68% do K, 57% do Ca, 56% do Mg e 81% do S acumulado pela planta.This research was aimed at counting the concentration of macronutrients throughout the onion, cv Superex, established by direct seeding. The experiment was conducted at Rio Doce farm, between the counties of Itobi and São José do Rio Pardo, state of São Paulo, Brazil (21°37'16"S and 46°53'15"W. The macronutrients N, P, K, Ca, Mg, and S as well as plant dry matter content were evaluated in plant samples taken at 30, 50, 70, 90, 110, and 150 days after seeding (DAS. The maximum dry matter content in the bulb and in the aerial part were reached at 150 DAS and were, respectively, of 4.70 and 17.86g plant-1. The aerial part and the bulb contributed respectively with 20 and 80% of the whole mature plant dry matter. The macronutrients were accumulated in the plant in the following order: K>N>Ca>S>Mg>P. The onion plant accumulated 202.43; 31.23; 295.28; 172.42; 35.20 e 73.47 mg of N, P, K, Ca, Mg, and S, respectively, and

  8. AcEST: DK955197 [AcEST

    Full Text Available TST39A01NGRL0022_H07 532 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0022_H07. 5' end seq ... KDEVTALPLLK 192 Query: 194 RFAFGIACELLMSRYEKEEQEMLEEPF TTMMKGILQLPIKLPGTRFSKAIVAANMLRARF 373 R+ F +AC+L S ... KDEVMALPLLK 192 Query: 194 RFAFGIACELLMSRYEKEEQEMLEEPF TTMMKGILQLPIKLPGTRFSKAIVAANMLRARF 373 R+ F +AC+L S ... KDEVKVLP 189 Query: 185 LMKRFAFGIACELLMSRYEKEEQEMLEEPF TTMMKGILQLPIKLPGTRFSKAIVAANMLR 364 L++ F IA L + +Q+ ... KDEATVLP 177 Query: 185 LMKRFAFGIACELLMSRYEKEEQEMLEEPF TTMMKGILQLPIKLPGTRFSKAIVAANMLR 364 L+K F +A L E+ QE ...

  9. AcEST: BP915640 [AcEST

    Full Text Available YMU001_000074_A01 462 Adiantum capillus-veneris mRNA. clone: YMU001_000074_A01. BP915640 CL3685C ... y: 462 GPLILRACLVYMQGAPVGSLAEDGIVSAATGKDMEQSTVGFRLMLAKI IHRLIAAFKEVG 283 G IL+AC YM+G +GSL +D V ++VGF+LMLAK ... : 1032 GYYILKACDAYMKGYLIGSLTKDASVIDERSS-ANSTSVGFKLMLAKI APKLFSALSEVG 1090 Query: 282 AYCDAYE 262 A C+ ++ Sb ... uery: 453 ILRACLVYMQGAPVGSLAEDGIVSAATGKDMEQSTVGFRLMLAKI IHRLIAAFKEVGAYC 274 +L AC YM+G PVGS A G ST GF++ML+K ... ame = -1 Query: 423 GAPVGSLAEDGIVSAATGKDMEQSTVGFRLMLAKI I----HRLIAAFKEVGAYCD 271 G P+ L D +S GK + S RL + L+ ...

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

    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.

  11. AcEST: BP920800 [AcEST

    Full Text Available DLNLALQVHSRMVRFGFNAEVEACGALINMYGKCGKVLYAQRVFDDT 298 Query: 206 RQQDVISWNDIISACAQRGHGTEALENFSQMLHEGIVPNSMTFTSVMQA---CNSIEGG...G L +A S F ++ +D+ISW +I +Q EA+ F Sbjct: 217 SEKNEATSNCLINGYMGLGNLEQAESLFNQMPVKDIISWTTMIKGYSQNKRYREAIAVFY 276 Query: 119 QMLHEG...EKAWRIFDGVSCKNLPSWNAIITGCVQGGLLEEAIDLYRHMK 281 Query: 110 HEGIVPNSMTFTSVMQAC---NSIEGGR 36 + + PN +T +V+ AC +...N IIS AQ G +EA+E ++ M Sbjct: 383 DITIGNAVVVMYAKLGLVDSARAVFNWLPNTDVISWNTIISGYAQNGFASEAIEMYNIME 442 Query: 110 HEG...EIDLGEQIHSLSVKTGFESDMYVSGVLIDMYSKYGWLEKARRVLEML 406 Query: 206 RQQDVISWNDIISACAQRGHGTEALENFSQMLHEGIVPNSMTFTSVMQACNSIEGG

  12. AcEST: DK945549 [AcEST

    Full Text Available AGGCGATTTCATCTTTTCTGAGAACCCTGATTTTGTGATTGTGTAATTACA ACTGTGGAACAGAAGGATGAGAAGTCTACTGACACAACAAGATATCTCTGGAGAGGAGA...A AATTGAGAAGGTTTGAGTTCTCAACAATGGGCTATGAGGCAATAATGGGAAGGCACCGAT TGTGGGCTTGTATAGGTTTTGAC...LCTG 239 L++R+LRR + + ++ G AC+ DP +P PLC+G Sbjct: 108 LQQRELRRKLLADSGALNTNSVNGPRNWKACVQQDPSSRPGTPLCSG 154 >sp|A6UUY8|RNZ_META3...49 Tissue type young leaves Developmental stage sporophyte Contig ID CL454Contig1 Sequence GATGAGCGA...CCACCTGTGCAACCGTCAGCGCCTTTGTGCACTGGTG CAATGTCCTGTGGTTACCTTGTTTGGAATCTTAATTGTTCTCATGTAT

  13. AcEST: BP917632 [AcEST

    Full Text Available YMU001_000103_D10 554 Adiantum capillus-veneris mRNA. clone: YMU001_000103_D10. BP917632 - Show ... YSKCKIHQKALELLVLML 154 Query: 466 KDSLEPDEVTYLNVLKACARE EDLKV 543 +D++ P+ TY +VL++C D+++ Sbjct: 155 RDNVRPN ... 185 Query: 415 GHSDSS--KEALKLLTQMRKDSLEPDEVTYLNVLKACARE EDLK 540 + EA KL +M+ ++ PDE+ N++ AC R +++ Sbjct: 18 ...

  14. AcEST: DK961189 [AcEST

    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=

  15. AcEST: DK946687 [AcEST

    Full Text Available YMU02A01NGRL0013_G11 544 Adiantum capillus-veneris mRNA. clone: YMU02A01NGRL0013_G11. 5' end seq ... + G P+ TY+ + AC+ E Sbjct: 97 YSFNYMIRGLTNTWN-------DHEA ---ALSLYRRMKFSGLKPDKFTYNFVFIACAKLE 146 Query: 214 A ... Sbjct: 71 LIPKAVELGDFNYSSFLFSVTEEPNHYSFNYMIRGLTNTWNDHEA ALSLYRRMKFSGLKP 130 Query: 469 DGATFSCVLRACGNVGALDV ...

  16. AcEST: DK949372 [AcEST

    Full Text Available TST38A01NGRL0005_N02 627 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0005_N02. 5' end seq ... 363 DQLREKTC-GVDKFDDIVMACXXXXXXXXXXXXXXXXXXKARVHAYGVCD DPEYFYDYVQ 539 Q++EK G+ FDDIV+AC KA+VHA+ VCD DP+YFYD ... 264 QQVQEKKVPGITFFDDIVVACGSGGSIAGLSLGSYLSNLKAKVHAFAVCD DPDYFYDYTQ 323 Query: 540 GLLDGMNANIASRDIVNVIDAKGLG ...

  17. Consumerism triggers AC explosion

    Lafferty, Richard

    1997-05-01

    The growth in air conditioning in the United Kingdom in recent years is examined in this article, and split systems, the phasing out of CFC and HCFC refrigerants, global warming, and comfort levels are considered. (UK)

  18. DC injection into low voltage AC networks

    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.

  19. Modelling of an adsorption system driven by engine waste heat for truck cabin a/c. Performance estimation for a standard driving cycle

    Verde, M.; Cortés, L.; Corberán, J.M.; Sapienza, A.; Vasta, S.; Restuccia, G

    2010-01-01

    Abstract This paper presents the main characteristics of an innovative cooling system for the air-conditioning of a truck cabin, as well as a first estimation of its performance during a standard driving cycle, obtained with a specifically developed vehicle-engine-cooling system overall model. The innovative cooling system consists of a water-zeolite adsorption-desorption system, which employs the waste heat from the engine to produce the cooling of the vehicle cabin. The developed...

  20. Energy saving in ac generators

    Nola, F. J.

    1980-01-01

    Circuit cuts no-load losses, without sacrificing full-load power. Phase-contro circuit includes gate-controlled semiconductor switch that cuts off applied voltage for most of ac cycle if generator idling. Switch "on" time increases when generator is in operation.

  1. Apuntes de Acústica

    Martín Domingo, Agustín

    2014-01-01

    Esta publicacion contiene unos apuntes para la parte de Acústica de las asignaturas de la ETSAM, junto con cierta cantidad de material adicional que excede el ámbito del curso. Aunque está lejos de ser completa y de estar libre de errores, el autor espera sea útil.

  2. SSTI Clark ACS Technology Demonstrations

    Freesland, Douglas

    1997-01-01

    SSTI Clark, one of two spacecraft built under NASA's Small Satellite Technology Initiative, includes seven ACS technology demonstrations. The technologies redefine the performance cost envelope, providing improved sensor and actuator performance at reduced costs. Six sensing technologies are being flown consisting of both hardware and algorithmic demonstrations: autonomous star tracker, hemispherical resonating gyro, GPS attitude determination, miniature horizon sensors, low cost course sun s...

  3. Offshore windfarm connection with low frequency AC transmission technology

    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...

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

    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.

  5. AC 95 - selected readings

    NONE

    1995-12-31

    Reports are presented on energy efficiency and conservation in residential buildings. Topics include housing and energy linkages; the people factor; low-income initiatives; green visions; utility programs; affordable comfort; housing as a system; and pressures and air flow in buildings.

  6. Concurrent Electroencephalography Recording During Transcranial Alternating Current Stimulation (tACS).

    Fehér, Kristoffer D; Morishima, Yosuke

    2016-01-01

    Oscillatory brain activities are considered to reflect the basis of rhythmic changes in transmission efficacy across brain networks and are assumed to integrate cognitive neural processes. Transcranial alternating current stimulation (tACS) holds the promise to elucidate the causal link between specific frequencies of oscillatory brain activity and cognitive processes. Simultaneous electroencephalography (EEG) recording during tACS would offer an opportunity to directly explore immediate neurophysiological effects of tACS. However, it is not trivial to measure EEG signals during tACS, as tACS creates a huge artifact in EEG data. Here we explain how to set up concurrent tACS-EEG experiments. Two necessary considerations for successful EEG recording while applying tACS are highlighted. First, bridging of the tACS and EEG electrodes via leaking EEG gel immediately saturates the EEG amplifier. To avoid bridging via gel, the viscosity of the EEG gel is the most important parameter. The EEG gel must be viscous to avoid bridging, but at the same time sufficiently fluid to create contact between the tACS electrode and the scalp. Second, due to the large amplitude of the tACS artifact, it is important to consider using an EEG system with a high resolution analog-to-digital (A/D) converter. In particular, the magnitude of the tACS artifact can exceed 100 mV at the vicinity of a stimulation electrode when 1 mA tACS is applied. The resolution of the A/D converter is of importance to measure good quality EEG data from the vicinity of the stimulation site. By following these guidelines for the procedures and technical considerations, successful concurrent EEG recording during tACS will be realized. PMID:26862814

  7. Experiments on Corona Discharge Under AC and DC Composite Voltage

    ZHU Zhengyi; LI Ruihai; WANG Guoli; CHEN Can; JIA Zhidong; GUAN Zhicheng

    2012-01-01

    Converter transformers are one of the most important electrical apparatuses in the ultra high voltage(UHV) DC transmission systems.The valve side and the low voltage(LV) bushing are stressed by long-term AC and DC composite voltage leading to significant partial discharge(PD) and posing great danger to the insulation system.In this paper AC and DC composite voltage is applied on a metal needle-plate model to produce PD signal sequences,and then the pulse waveshape and frequency spectrum are analyzed and compared with PD signals under conventional AC or DC voltage.In the end,the phase-resolved distribution is analyzed to depict the new characteristics of PD under this composite voltage.

  8. AcEST: DK950895 [AcEST

    Full Text Available |A7SFA3|A7SFA3_NEMVE Predicted protein OS=Nematostella vectens... 210 5e-53 tr|Q0CVA9|Q0CVA9_ASPTN ATP-citrate synthase subunit...stX Result : Swiss-Prot sp_hit_id Q54YA0 Definition sp|Q54YA0|ACLY_DICDI Probable ATP-citrate synthase OS=Dictyos...PIDYSWAQELGLIRKPAAFISTI 404 >sp|Q8X097|ACL1_NEUCR Probable ATP-citrate synthase subunit 1 OS=Neurospora cras...IRKPASFMTSI 844 >sp|Q9P7W3|ACL1_SCHPO Probable ATP-citrate synthase subunit 1 OS=Schizosaccharomyces pombe G....done Score E Sequences producing significant alignments: (bits) Value sp|Q54YA0|ACLY_DICDI Probable ATP-citrate synthase OS=Dictyos

  9. AcEST: BP914304 [AcEST

    Full Text Available IDEHTFVFTLRAC 4 V+ NA++ Y G+ E A++ + +M+ E++ + TF+ LRAC Sbjct: 670 VTWNAMICGYAHHGKGEEAIQLFERMILENIKPNHVTFISI...KSLRRDFVTWNAMICGYAHHGKGEEAIQLFERMILENIKPN 703 Query: 339 NLTYVSLFKACGNVLDFGQG-RTIHGEARANGFSSDRFICTTLI...TFVFTLRAC 4 +F + + V+ N ++ +YV A +++M + D TL+AC Sbjct: 484 QIFERMCDRDNVTWNTIIGSYVQDENESEAFDLFKRMNLCGIVSDGACL...K + A+Q+ + R + +W++MI++ +A + ++ M Sbjct: 93 LGNSLINFYSKFEDVASAEQVFRRMTLRDVVTWSSMIAAYAGNNHPAKAFDTFERMTDAN 152... + R + +W++MI++ +A + ++ M Sbjct: 93 LGNSLINFYSKFEDVASAEQVFRRMTLRDVVTWSSMIAAYAGNNHPAKAFDTFERM

  10. AcEST: BP911793 [AcEST

    Full Text Available + +VSWN +++ Y QHG + ++L+ M+AE T N + + A Sbjct: 58 EAKFVFERIQNKDVVSWNCIINGYSQHGPSGSSHVMELFQRMRAENTAPNAHTFAGVF... N + + A Sbjct: 58 EAKFVFERIQNKDVVSWNCIINGYSQHGPSGSSHVMELFQRMRAENTAPNAHTFAGVFTA 117 Query: 359 CIQTGNLELCKQM...D VT S+LSACSH G + +G YF Sbjct: 602 IIGGSAQHGRGQDALQLFERMKMEGVKPDIVTFVSLLSACSHAGLLEEGRRYF 654 Score = 115 bit...53 QTGNLELCKQMHFNIVSAGNELNPSLASSLIRTYGNCGSMLDAHAVFDSLPLPDIVSWNV 174 Q +E+ K++ F+++ N S +++I Y CG + +A +FD +P D VSW Sbjct: 324 QGERME... L+ M +E + I+LV +L AC+ TG+LE + +H Sbjct: 498 VITWNAMIASYVHCEQSEKAIALFDRMVSENFKPSSITLVTLLMACVNTGSLER

  11. AcEST: BP921649 [AcEST

    Full Text Available 40 + ++LV YAK L + ++ +P R W+ +I+ + + ++E AL+ + M+ G Sbjct: 144 VASSLVGMYAKFNLFENSLQVFDEMPERDVASWNTVISCFYQSGEAEKALELFGRME...LDCYKEM 52 ++L +GNALVD YAKCG L A ++ +R+ R V W+ +I Y + E A D +K M Sbjct: 461 KNLFVGNALVDMYAKCGALEDARQIFERMCDRDNVTWNTIIGSYVQDEN...RD+ WNA+I Sbjct: 237 LEQGKQIHCYAIRSG-IESDVLVVNGLVNMYAKCGNVNTAHKLFERMPIRDVASWNAIIG 295 Query: 411 GYVNHGRAEVALDCFGKME...SNDVV-GNALVNMYAKCGNVNSAYKLFERMPKKNVVAWNAIIS 396 Query: 411 GYVNHGRAEVALDCFGKME... HGR + AL F +M+ EG PD +TF +L AC G + + + + Sbjct: 603 IGGSAQHGRGQDALQLFERMKMEGVKPDIVTFVSLLSACSHAGLLEEGRRYFCSM

  12. AcEST: BP919669 [AcEST

    Full Text Available D + RDV SW ++S + + G+ ++F M G +P+ Sbjct: 148 LVGMYAKFNLFENSLQVFDEMPERDVASWNTVISCFYQSGEAEKALELFGRMESSGFEPN 20...+ +++AC L + +G+E+H + K+G EL V Sbjct: 190 EKALELFGRMESSGFEPNSVSLTVAISACSRLLWLERGKE...F Sbjct: 468 IY---VVNSLIDSYGKCSHVEDAERIFEECTIGDLVSFTSMITAYAQYGQGEEALKLFLE 524 Query: 226 MVGEGTKPDSISLLVVLRA-YNF...+ IR DV W +LMSGY+K D ++F ++ Sbjct: 44 SLINVYFTCKDHCSARHVFENFDIRSDVYIWNSLMSGYSKNSMFHDTLEVFKRLLNCSIC 103 Query: 208 KPDSISLLVVLRAYNF...KPD Sbjct: 261 VDMYAKCGCIETAVEVFEKLTRRNVFSWAALIGGYAAYGYAKKATTCLDRIEREDGIKPD 320 Query: 199 SISLLVVLRAYNFLGFP

  13. AcEST: DK957916 [AcEST

    Full Text Available PQKQPVPAVSHSPQKSSTPPTPAATKPKEEPSVPKEVPKLQQGKLEKT 967 Query: 577 --TTEASQGIPVEEG...G E+ P+ P Sbjct: 1974 QEQGRAPSQDQEAPSPEALPSPGQEPAAGASPRRGELRRGSSAESALPRAGP 2025 >sp|Q05175|BASP_RAT Brain ac... +P AP P Sbjct: 388 ERETAASAGPQG----AFPEPRPAQPSAGPEPRPAQPSAGPEPRPAQPSAAPEPRP---- 439 Query: 571 GQTTE... L ++ +A+ +E AP Sbjct: 406 IVTTPEPEGSGEEDVPKPDEIPEKEVTEEELIKVSTAAPAKASPEEEVVKATTLAPSEED 465 Query: 550 VSPYIASGQTTE... Query: 424 KGQAYEAIPDPHVDPAAGVHERLAQLQLGDEPEATKPKEAPG-VSPYI--ASGQTTEASQ 594 K A E P + + G E + E EA P A G +P

  14. AcEST: DK956923 [AcEST

    Full Text Available CCATAGTCTCAA CAGCGATAAGCAGGAAATGCATGCAGTGACCATGGGTAAGAAAAGGGTCATGGTGGGCGC CATTAACACGATACTTATCCTA...CTCCTCTTGCAGTTTATGAAGCAATGTTCTTCCTCTTC TAGTCATGATGATGATGGCGATGCCTTTGCGGATGACACTCTAAGCAGACGCAACGAT...AC GGTCGAGTCTGCTCCTCGACATTGGCCAAGGCGAATGCTGGGCAGCCAAGAACCTGCCTC CAACAAGACTTCATATGGTATTCCTGAT...H At1g73965 (CLE13 / CLAVATA3/ESR-Related 13) (CLE13) OS=Arabidopsis thaliana Align length 25 Sco...icant alignments: (bits) Value tr|Q6NMF0|Q6NMF0_ARATH At1g73965 (CLE13 / CLAVATA3/ESR-Related 1... 49 3e-04

  15. AcEST: BP921492 [AcEST

    Full Text Available + AL +G+ +H Sbjct: 286 DVASWNAIIGGYSLNSQHHEALAFFNRMQVRGIKPNSITMVSVLPACAHLFAL... ++ L +GK +H Sbjct: 178 NLVSWTAMVSGYAQGGFADEALRMFYEMQGEDVKANYVTVASVLPACAQLSDLQQGKEIH 237 Query: 153 AC...FDRMPEK 171 Query: 333 DVVSWSAMIAMYGQQGCGKEAFQLFQEMACEGGMPNRVTYVSILDACASVAALPEGKLVH 154 +V+W+++++ + Q G EA Q+F +M G P+ T+VS+L ACA...333 DVVSWSAMIAMYGQQGCGKEAFQLFQEMACE-GGMPNRVTYVSILDACASVAALPEGKLV 157 +V +W+AMI+ YG G G++A +LF +M + G +PN VT+V++L ACA...SKL 85 Query: 288 GCGKEAFQLFQEMACEGGMPNRVTYVSILDACASVAALPEGKLVHACFMESELELDVVVG 109 ++ M P+ T+ S++ +CA ++AL G

  16. Micronutrientes no sistema solo-Pinus caribaea Morelet em plantios apresentando amarelecimento das acículas e morte de plantas Micronutrients in the soil-Pinus caribaea Morelet System with yellowing of the needles followed by senescence and death

    Roselene de Queiroz Chaves; Gilberto Fernandes Corrêa

    2003-01-01

    Com o objetivo de contribuir no diagnóstico de causas que têm levado à morte precoce de pinheiros, verificada após amarelecimento e necrose progressiva das acículas, foi desenvolvido este estudo em áreas de cerrado, no oeste de Minas Gerais. Foram comparadas árvores de Pinus caribaea Morelet das variedades caribaea e hondurensis, plantadas entre 1977-82. Em cada local de amostragem coletou-se material de 20 árvores, sendo 10 com acículas amarelecidas e 10 normais. Foram coletados acículas e t...

  17. Djungle power. A more remote AC bus

    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.)

  18. Acúmulo de macronutrientes por duas cultivares de cebola produzidas em sistema de semeadura direta Accumulation of macronutrients by two onion cultivars on direct sowing system

    André May

    2008-01-01

    Full Text Available No Brasil, a cebola é considerada a terceira hortaliça mais importante em termos de valor econômico. Contudo, com o advento do uso de novas cultivares híbridas há necessidade do estudo de seu manejo nutricional. Dessa forma, esta pesquisa, realizada em São José do Rio Pardo (SP, de 7 de março a 8 de agosto de 2004, objetivou quantificar o acúmulo de macronutrientes por duas cultivares de cebola estabelecida por semeadura direta. O delineamento experimental utilizado foi o de blocos ao acaso, com três repetições, sendo estudadas as cultivares Optima e Superex. As amostragens de plantas foram realizadas aos 30, 50, 70, 90, 110, 130 e 150 dias após a semeadura. Para uma população de 354.000 plantas ha-1 e uma produtividade estimada de 64,8 t ha-1, a 'Optima' extraiu aos 150 dias após a semeadura: 78,77; 13,04; 75,77; 59,09; 11,70 e 24,38 kg ha-1, respectivamente, de N, P, K, Ca, Mg e S. 'Superex' na mesma população de plantas e uma produtividade de 72 t ha-1 extraiu 64,68; 10,33; 68,28; 65,58; 13,03; 24,74 kg ha-1, respectivamente, de N, P, K, Ca, Mg e S. A cultivar Optima exportou pelo bulbo em relação à planta inteira 49,17% do N, 60,60% do P, 61,16% do K, 41,15% do Ca, 43,56% do Mg e 47,18 do S, o que correspondeu a 38,73; 7,90; 46,34; 24,32; 5,10 e 11,51 kg ha-1 respectivamente. A cultivar Superex exportou pelo bulbo em relação à planta inteira 44,29% do N, 55,85% do P, 62,54% do K, 35,71% do Ca, 31,82% do Mg e 48,80% do S, o que correspondeu a 28,65; 5,77; 42,70; 23,42; 4,15 e 12,07 kg ha-1 respectivamente.Economically, onion is the third more important vegetable in Brazil. As a consequence of the increasing by use of new hybrid varieties, the nutritional management of the crop needs to be adequately known. This research was carried out in São José do Rio Pardo, São Paulo State, Brazil, from March 7 to August 8, 2004. The objective was to quantify, under field conditions, the accumulation of macronutrients by onion

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

    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)

  20. Removal of nitrate ions from water by activated carbons (ACs)—Influence of surface chemistry of ACs and coexisting chloride and sulfate ions

    Ota, Kazunari; Amano, Yoshimasa; Aikawa, Masami; Machida, Motoi

    2013-07-01

    Adsorptive removal of nitrate ions in aqueous solution using activated carbons (ACs) was examined. After ash was removed from Filtrasorb 400 AC, oxidation and outgassing and several heat treatments were carried out to modify the textural and surface properties of ACs. AC oxidized with 8 M nitric acid followed by outgassing at 900 °C (Ox-9OG) exhibited the greatest Langmuir adsorption capacity and affinity for nitrate removal among the total 7 ACs examined. Influence of coexisting chloride and sulfate ions was investigated as well to inspect the nitrate adsorption sites. The highest amount of sites which adsorbed nitrate ions exclusively could be observed for Ox-9OG adsorbent even though as great as 250 times greater number of chloride or sulfate ions over nitrate ions were present in the same aqueous system. Some basic oxygen species on carbon were estimated to work as selective adsorption sites for nitrate ions.

  1. Design and simulation of full digital SVPWM AC speed control system%全数字化SVPWM调速系统的设计与仿真

    刘刚利

    2011-01-01

    The implementation scheme to realize vector variable speed system using low -cost embedded system was presented in this paper.The design of the system software, hardware was optimized, and simulation was carried out.Simulation results demonstrated that the performance of space vector variable speed system was excellent, all parts of the theoretical analysis were correct, parameters were set comparatively appropriate, voltage and current output waveforms met the requirements, speed met the beat control requirements, and there was almost no oscillation.The system design is instructive to control production costs and increase commonality, and the system simulation is important to produce the prototype, shorten the design cycle and improve production efficiency.%该文提出了使用价格低廉的嵌入式系统实现矢量变频调速系统的实施方案,对系统软件、硬件设计进行了优化,并实施仿真.仿真表明,设计的空间矢量变频调速系统性能优异,各个部分的理论分析正确,参数配合比较恰当,电压、电流输出波形达到要求,转速符合最少拍控制要求,基本无振荡.系统的设计对控制生产成本、增强通用性具有指导意义,系统的仿真对样机制作、缩短设计周期、提高生产效率具有重要意义.

  2. EHV AC undergrounding electrical power performance and planning

    Benato, Roberto

    2010-01-01

    EHV AC Undergrounding Electrical Power discusses methods of analysis for cable performance and for the behaviour of cable, mixed and overhead lines. The authors discuss the undergrounding of electrical power and develop procedures based on the standard equations of transmission lines. They also provide technical and economical comparisons of a variety of cables and analysis methods, in order to examine the performance of AC power transmission systems. A range of topics are covered, including: energization and de-energization phenomena of transmission lines; power quality; and cable safety cons

  3. Voltage drop of the SACLA AC power supply

    We installed the AC power supply of SACLA by construction. The AC power supply is connected to an inverter power supply. Because of charge and discharge to a modulator, it is necessary to supply pulsatile electricity. The total consumption electricity of approximately 70 modulators extends to 5,000kVA. A severe electric current flows, and repeats relaxing. The influence of the voltage change by the impedance of the distribution system grows big, too. In SACLA, we designed the voltage regulation at less than 10%. SACLA succeeded in laser oscillation in this June. Because we was able to put it in the predetermined voltage regulation in the machine AC power supply, I report the details. (author)

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

    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. .

  5. Evaluation of the Impact of the Additional Mass of an Innovative AC System on the Overall Energy Consumption of a Battery Electric Vehicle in Tropical Climate

    Ramachandran, Srikkanth; Subiantoro, Alison; Ooi, Kim Tiow

    2015-01-01

    One of the major issues concerning the inclusion of additional components in vehicle for its efficiency improvement is the increase in mass of the vehicle. The increased mass causes an increased energy demand for propulsion of the vehicle. This paper aims at analyzing the impact of the added mass of an innovative air conditioning system powered by bio-ethanol based auxiliary power unit on the overall energy use of electric vehicles that are designed for the tropical climate of Singapore.

  6. Modelling ac ripple currents in HTS coated conductors

    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

  7. The Globular Cluster System of the Coma cD Galaxy NGC 4874 from Hubble Space Telescope ACS and WFC3/IR Imaging

    Cho, Hyejeon; Blakeslee, John P.; Chies-Santos, Ana L.; Jee, M. James; Jensen, Joseph B.; Peng, Eric W.; Lee, Young-Wook

    2016-05-01

    We present new Hubble Space Telescope (HST) optical and near-infrared (NIR) photometry of the rich globular cluster (GC) system NGC 4874, the cD galaxy in the core of the Coma cluster (Abell 1656). NGC 4874 was observed with the HST Advanced Camera for Surveys in the F475W (g 475) and F814W (I 814) passbands and with the Wide Field Camera 3 IR Channel in F160W (H 160). The GCs in this field exhibit a bimodal optical color distribution with more than half of the GCs falling on the red side at g 475‑I 814 > 1. Bimodality is also present, though less conspicuously, in the optical-NIR I 814‑H 160 color. Consistent with past work, we find evidence for nonlinearity in the g 475‑I 814 versus I 814‑H 160 color–color relation. Our results thus underscore the need for understanding the detailed form of the color–metallicity relations in interpreting observational data on GC bimodality. We also find a very strong color–magnitude trend, or “blue tilt,” for the blue component of the optical color distribution of the NGC 4874 GC system. A similarly strong trend is present for the overall mean I 814‑H 160 color as a function of magnitude; for M 814 < ‑10 mag, these trends imply a steep mass–metallicity scaling with Z\\propto {M}{{GC}}1.4+/- 0.4, but the scaling is not a simple power law and becomes much weaker at lower masses. As in other similar systems, the spatial distribution of the blue GCs is more extended than that of the red GCs, partly because of blue GCs associated with surrounding cluster galaxies. In addition, the center of the GC system is displaced by 4 ± 1 kpc toward the southwest from the luminosity center of NGC 4874, in the direction of NGC 4872. Finally, we remark on a dwarf elliptical galaxy with a noticeably asymmetrical GC distribution. Interestingly, this dwarf has a velocity of nearly ‑3000 km s‑1 with respect to NGC 4874; we suggest it is on its first infall into the cluster core and is undergoing stripping of its GC system by

  8. AcEST: DK948526 [AcEST

    Full Text Available TST38A01NGRL0003_I19 675 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0003_I19. 5' end seq ... IAMVRTTTPVYV 214 Query: 542 ALALFNQARVSSLPIIDDNGSLIDIY ARSDITALARDDTY 661 AL +F Q RVS+LP++D+ G ++DIY ++ D+ ... LA + TY Sbjct: 215 ALGIFVQHRVSALPVVDEKGRVVDIY SKFDVINLAAEKTY 254 >sp|Q09138|AAKG1_PIG 5'-AMP-acti ... IAMVRTTTPVYV 215 Query: 542 ALALFNQARVSSLPIIDDNGSLIDIY ARSDITALARDDTY 661 AL +F Q RVS+LP++D+ G ++DIY ++ D+ ... LA + TY Sbjct: 216 ALGIFVQHRVSALPVVDEKGRVVDIY SKFDVINLAAEKTY 255 >sp|O54950|AAKG1_MOUSE 5'-AMP-ac ...

  9. AcEST: DK962916 [AcEST

    Full Text Available TST39A01NGRL0015_C06 596 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0015_C06. 5' end seq ... NA. clone: TST39A01NGRL0015_C06. 5' end sequence. Acce ssion DK962916 Tissue type prothallia with plantlet ... 2 Query: 317 MPKSKEPCSQEACDIQTCLVKNNFITERCFPVIEALQACCE K 442 MP+ K+PC ++AC+IQ CL NN++ +C VI+ L+ CC + Sbjct ... me = +2 Query: 335 PCSQEACDIQTCLVKNNFITERCFPVIEALQACCE K 442 PC +EAC IQ CL+ + + +C VI+ L CC K Sbjct: 4 PCQ ... = +2 Query: 326 SKEPCSQEACDIQTCLVKNNFITERCFPVIEALQACCE KCNSK 454 + E C+ CD +TC +K F +C AL CCE KC K Sbjct: 4 ...

  10. AcEST: DK955705 [AcEST

    Full Text Available TST39A01NGRL0023_N02 635 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0023_N02. 5' end seq ... NA. clone: TST39A01NGRL0023_N02. 5' end sequence. Acce ssion DK955705 Tissue type prothallia with plantlet ... 2 Query: 296 MPKSKEPCSQEACDIQTCLVKNNFITERCFPVIEALQACCE K 421 MP+ K+PC ++AC+IQ CL NN++ +C VI+ L+ CC + Sbjct ... me = +2 Query: 314 PCSQEACDIQTCLVKNNFITERCFPVIEALQACCE K 421 PC +EAC IQ CL+ + + +C VI+ L CC K Sbjct: 4 PCQ ... = +2 Query: 305 SKEPCSQEACDIQTCLVKNNFITERCFPVIEALQACCE KCNSK 433 + E C+ CD +TC +K F +C AL CCE KC K Sbjct: 4 ...

  11. AcEST: DK961330 [AcEST

    Full Text Available FWVPCMHTPIKQEKHTHA 405 +AR P W +++PI+ ++C++ P + AK+ PL DVTH+F+V + +QE Sbjct: 61 VARRTRP-SWHEDNPINYVQCDISDPDD...+IL +D PGGPWKVYG Sbjct: 4 WWAGAIGAAKKKLEEDDAPPKHS---SVALIVGVTGIIGNSLAEILPLADTPGGP...AWHEDNPINYIQCDISDPDDSLAKLSPLTDVTHVFYVTCANR--STEPENCE 117 Query: 406 MATHMFENIIGVLLTHAPNLQHVCMQTSDKHY-... : Swiss-Prot sp_hit_id Q7MXT7 Definition sp|Q7MXT7|LPXD_PORGI UDP-3-O-[3-hydroxymyristoyl] glucosamine N-ac...lue sp|Q7MXT7|LPXD_PORGI UDP-3-O-[3-hydroxymyristoyl] glucosamine N-... 34 0.62 sp|P60369|KR103_HUMAN Kerati

  12. AcEST: BP913772 [AcEST

    Full Text Available N VT V L C+ G G+ H Sbjct: 350 NVVTWSAVIAGYAQRGLGFEALDVFRQMRLCGSEPNVVTLVSLLSGCALAGTLLHGKETH 409 Query: 376 IEIER--RGLLEVDP-...VFNKLSVQDIVSW 236 + + A ++G+++H I RRGL + PV+ + LV MY R G L Q VF+++ +D+VSW Sbjct: 296 ASLAALEQGKLIHGYILRRGLDSILPVI-S... TF M+ +PN+VT V VL+AC+ + Q + Sbjct: 250 SWSAMIACYAKNGKAFEALRTFREMMRETKDSSPNSVTMVSVLQACASLA...MIEGGVAPNAVTFVVVLRACSQTGSYSQSQTFFEAMSKNF 50 + G A G + F+ M + GV PNAVTFV VLR CS G + Q F++M F Sbjct: 312 ALNGLAMNGFGEKCLELFSL...L YA G + + +F++ D+ +TA + + Sbjct: 48 IHAAILRHNLLLHPRYPVLNLKLHRAYASHGKIRHSLALFHQTIDP

  13. AcEST: DK952954 [AcEST

    Full Text Available TST38A01NGRL0015_H21 616 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0015_H21. 5' end seq ... LIHAHIVCSCNDVDNFVRSTLVNLYSKCGSIEDAHNVFAKLATRRSVDWSMMIS ... 541 ++ Q K +HA I + D + V + L+++Y+KCGSI DA F +++T+ ... LIHAHIVCSCNDVDNFVRSTLVNLYSKCGSIEDAHNVFAKLATRRSVDWSMMIS GS 547 + + IHA S D ++ LV LYS+CG IE+++ F + ++ W+ ++S ... LIHAHIVCSCNDVDNFVRSTLVNLYSKCGSIEDAHNVFAKLATRRSVDWSMMIS ... 541 DL + IH+ I+ + ++ +V S L+++Y+K G ++ A ++ + A + ... EA+ LF +M G+ P + + L AC Sbjct: 243 RVFDGLRLKDHSSWVAMIS GLSKNECEAEAIRLFCDMYVLGIMPTPYAFSSVLSACKKIE 302 Query ...

  14. AcEST: BP912540 [AcEST

    Full Text Available YMU001_000020_B03 501 Adiantum capillus-veneris mRNA. clone: YMU001_000020_B03. BP912540 - Show ... 2 EELTVHHTASVGDVEALKALLAEGADKDEKDSEGRTALHFACGYGEVMCAE VLLEAGVAV 181 EE VH TAS+GDVE LKA LA G +KDE+DSEGRTAL ... ry: 14 VHHTASVGDVEALKALLAEGADKDEKDSEGRTALHFACGYGEVMCAE VLLEAGVAVDAVD 193 +H A V ++ LL GAD KD G LH AC YG AE ... uery: 26 ASVGDVEALKALLAEGADKDEKDSEGR--TALHFACGYGEVMCAE VLLEAGVAVDAVDKN 199 + GD+E +K L + + + +D EGR T LHFA ... ry: 14 VHHTASVGDVEALKALLAEGADKDEKDSEGRTALHFACGYGEVMCAE VLLEAGVAVDAVD 193 +H A ++E + LL GAD + +D G LH A YG ...

  15. State of the Art analysis for the 'SolcelleInverter' project. Optimised design and control of inverter for photovoltaic systems: the AC-module

    Baekhoej Kjaer, S.

    2002-02-01

    The 'SolcelleInverter' project starts with this state-of-the-art analysis of 27 different inverter topologies for use in photovoltaic applications. The main concern is the present status for inverters for single solar modules. Technologies for larger clusters of modules are also investigated. The possibility of combining a small decentralised and a big centralised unit is as well investigated. A series of topologies are discovered and this paper will present them. That includes solutions with and without transformers, systems for one or multiple modules, commercial solutions and solutions found in scientific papers and patents. (au)

  16. A minimal tat system from a gram-positive organism - A bifunctional TatA subunit participates in discrete TatAC and TatA complexes

    Barnett, James P.; Eijlander, Robyn T.; Kuipers, Oscar P; Robinson, Colin

    2008-01-01

    The Tat system transports folded proteins across bacterial and thylakoid membranes. In Gram-negative organisms, a TatABC substrate-binding complex and separate TatA complex are believed to coalesce to form an active translocon, with all three subunits essential for translocation. Most Gram-positive organisms lack a tatB gene, indicating major differences in organization and possible differences in mode of action. Here, we have studied Tat complexes encoded by the tatAdCd genes of Bacillus sub...

  17. Dynamic Thermal Loads and Cooling Requirements Calculations for V ACs System in Nuclear Fuel Processing Facilities Using Computer Aided Energy Conservation Models

    In terms of nuclear safety, the most important function of ventilation air conditioning (VAC) systems is to maintain safe ambient conditions for components and structures important to safety inside the nuclear facility and to maintain appropriate working conditions for the plant's operating and maintenance staff. As a part of a study aimed to evaluate the performance of VAC system of the nuclear fuel cycle facility (NFCF) a computer model was developed and verified to evaluate the thermal loads and cooling requirements for different zones of fuel processing facility. The program is based on transfer function method (TFM) and it is used to calculate the dynamic heat gain by various multilayer walls constructions and windows hour by hour at any orientation of the building. The developed model was verified by comparing the obtained calculated results of the solar heat gain by a given building with the corresponding calculated values using finite difference method (FDM) and total equivalent temperature different method (TETD). As an example the developed program is used to calculate the cooling loads of the different zones of a typical nuclear fuel facility the results showed that the cooling capacities of the different cooling units of each zone of the facility meet the design requirements according to safety regulations in nuclear facilities.

  18. The Globular Cluster System of the Coma cD Galaxy NGC 4874 from Hubble Space Telescope ACS and WFC3/IR Imaging

    Cho, Hyejeon; Chies-Santos, Ana L; Jee, M James; Jensen, Joseph B; Peng, Eric W; Lee, Young-Wook

    2016-01-01

    We present new HST optical and near-infrared (NIR) photometry of the rich globular cluster (GC) system of NGC 4874, the cD galaxy in the core of the Coma cluster (Abell 1656). NGC 4874 was observed with the HST Advanced Camera for Surveys in the F475W (g) and F814W (I) passbands and the Wide Field Camera 3 IR Channel in F160W (H). The GCs in this field exhibit a bimodal optical color distribution with more than half of the GCs falling on the red side at g-I > 1. Bimodality is also present, though less conspicuously, in the optical-NIR I-H color. Consistent with past work, we find evidence for nonlinearity in the g-I versus I-H color-color relation. Our results thus underscore the need for understanding the detailed form of the color-metallicity relations in interpreting observational data on GC bimodality. We also find a very strong color-magnitude trend, or "blue tilt," for the blue component of the optical color distribution of the NGC 4874 GC system. A similarly strong trend is present for the overall mean...

  19. Photovoltaic Inverter Controllers Seeking AC Optimal Power Flow Solutions

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

    2014-01-01

    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...

  20. DC Voltage Droop Control Implementation in the AC/DC Power Flow Algorithm: Combinational Approach

    Akhter, F.; Macpherson, D.E.; Harrison, G.P.;

    2015-01-01

    In this paper, a combinational AC/DC power flow approach is proposed for the solution of the combined AC/DC network. The unified power flow approach is extended to include DC voltage droop control. In the VSC based MTDC grids, DC droop control is regarded as more advantageous in terms of...... operational flexibility, as more than one VSC station controls the DC link voltage of the MTDC system. This model enables the study of the effects of DC droop control on the power flows of the combined AC/DC system for steady state studies after VSC station outages or transient conditions without needing to...... use its complete dynamic model. Further, the proposed approach can be extended to include multiple AC and DC grids for combined AC/DC power flow analysis. The algorithm is implemented by modifying the MATPOWER based MATACDC program and the results shows that the algorithm works efficiently....

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

    Rakan Kh Antar

    2013-01-01

       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 fo...

  2. Effect of Tower Shadow and Wind Shear in a Wind Farm on AC Tie-Line Power Oscillations of Interconnected Power Systems

    Tan, Jin; Hu, Weihao; Wang, Xiaoru;

    2013-01-01

    This paper describes a frequency domain approach for evaluating the impact of tower shadow and wind shear effects (TSWS) on tie-line power oscillations. A simplified frequency domain model of an interconnected power system with a wind farm is developed. The transfer function, which relates the tie......-line power variation to the mechanical power variation of a wind turbine, and the expression of the maximum magnitude of tie-line power oscillations are derived to identify the resonant condition and evaluate the potential risk. The effects of the parameters on the resonant magnitude of the tie-line power...... are also discussed. The frequency domain analysis reveals that TSWS can excite large tie-line power oscillations if the frequency of TSWS approaches the tie-line resonant frequency, especially in the case that the wind farm is integrated into a relatively small grid and the tie-line of the...

  3. Evaluating conversion of AC power transmission lines to DC

    Edris, A. [EPRI, Palo Alto, CA (United States); Barthold, L. [IMod Inc., Lafayette, LA (United States); Douglass, D. [Power Delivery Consultants, Ballston Lake, NY (United States); Litzenberger, W. [Litzenberger Consultant (United States); Woodford, D. [Electranix, Winnipeg, MB (Canada)

    2008-07-01

    Conversion of alternating current (AC) transmission lines has been of significant interest for several years but has never been implemented to expand transmission line capacity or improve system security. This paper outlined the procedures necessary to identify and assess feasibility of specific AC to direct current (DC) conversion opportunities, with special focus on emerging DC transmission technologies. The paper outlined the process for investigating the conversion of an AC transmission line to DC. The investigation examined both bipole and tripole applications. A summary of the characteristics for alternative DC conversion configuration was presented. These characteristics included maximum transfer capability; redundancy; losses; overhead ratio; switching requirements; reactive power requirement; and accommodation of taps. The challenges and objectives of the project were also described. The paper provided a summary of the cost and benefit analysis for the various AC to DC conversion technologies for the Grand Coulee to Olympia transmission line. It was concluded that the project was particularly timely in that current work on the prospect of major North American system segmentation could benefit substantially, both technically and economically by having inter-system links take fuller advantage of the inherent DC capability of the circuits involved, thereby encouraging greater inter-regional energy exchange and providing the basis for lower energy supply costs. 12 refs., 2 tabs., 3 figs., 1 appendix.

  4. 风火打捆交直流外送系统功角暂态稳定研究%Study on Angle Transient Stability for Wind-thermal-bundled Power Transmitted by AC/DC System

    郭小江; 赵丽莉; 汤奕; 申洪

    2013-01-01

      风火打捆交直流外送是未来千万千瓦级风电能源基地电力外送的重要方式之一,亟需掌握风火打捆交直流外送系统的稳定特性及其机理。文章分析了不同风电比例和不同直流控制方式下系统的暂态功角稳定特性,探讨了风电、火电和直流系统间的交互作用,并基于扩展等面积(extended equal-area criterion,EEAC)理论分析了送受端机组惯量对系统功角暂态稳定性的影响机理。结果表明:在受端电网为无穷大系统的场景下,系统暂态功角稳定性随风电比例增加而改善;在送受端机组惯量可比场景下,存在最优风电与火电配置比例,使得系统暂态功角稳定性最好。%For the 10 GW wind power bases in China, wind-thermal-bundled power transmission by AC/DC system is regarded as one of feasible ways, but the stability characteristic of this kind of transmission systems should be investigated. In the paper, the angle transient stability characteristics were studied in the scenarios with different wind power penetration and DC control modes through simulations, and the interaction among wind power, thermal power and DC systems was discussed. Besides, the effects of the inertias of sending and receiving end systems on the angle transient stability characteristics were studied based on extended equal-area criterion (EEAC). When the receiving end power grid is equated to an infinite system, the system angle transient stability is improved with the increase of wind power penetration, while the equivalent inertia of the sending end can be comparable to that of the receiving end, there is an optimal wind power penetration with which the system has the highest angle transient stability.

  5. On-Chip AC self-test controller

    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.

  6. An Annotated Bibliography of High-Voltage Direct-Current Transmission and Flexible AC Transmission (FACTS) Devices, 1991-1993.

    Litzenberger, Wayne; Lava, Val

    1994-08-01

    References are contained for HVDC systems, converter stations and components, overhead transmission lines, cable transmission, system design and operations, simulation of high voltage direct current systems, high-voltage direct current installations, and flexible AC transmission system (FACTS).

  7. Performance Analysis of Phase Controlled Unidirectional and Bidirectional AC Voltage Controllers

    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.

  8. Research on Fuzzy Neural Network Control to AC Drive System Based on the Reinforcement Learning%基于再励学习的交流调速系统模糊神经网络控制

    杨威; 赵金; 张华军

    2011-01-01

    For vector control AC drive system, the thesis presented a fuzzy neural network speed controller based on reinforcement learning. The thesis introduced the on-line training method of neural network weight based on the genetic algorithm, simulated to compare the division of the input space, which is the number of fuzzy sets, so can see its impaction to the training and the control effect of fuzzy neural network controller.The simulation results show that the speed controller through the online training mode can obtain optimal parameters to adapt to changes in the parameters of the controlled object, and enable the system to obtain good dynamic and static performance.%针对矢量控制交流调速系统,该文提出并设计了一种基于再励学习的模糊神经网络速度控制器.详细介绍了基于遗传算法的神经网络权重在线训练方法,仿真对比了输入空间的划分即模糊子集数量对模糊神经网络控制器的训练及其控制效果的影响.仿真结果表明该速度控制器能通过在线训练方式获得最优参数以适应被控对象的参数变化,能使系统获得优良的动态和静态性能.

  9. Universality of ac conduction in disordered solids

    Dyre, Jeppe; Schrøder, Thomas

    2000-01-01

    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......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...

  10. Cooperative Frequency Control for Autonomous AC Microgrids

    Shafiee, Qobad; Quintero, Juan Carlos Vasquez; Guerrero, Josep M.; Nasirian, Vahidreza; Davoudi, Ali

    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...... different control parameters. This paper introduces a cooperative algorithm that regulates the system frequency while maintaining the power sharing properties of droop control. Dynamic consensus protocol is used to estimate the average of normalized active powers in the entire MG. This estimation is then...... added to primary control, compensating the frequency drop caused by the droop mechanism. The proposed controller is fully distributed, meaning that each source exchange information with only its direct neighbors through a sparse communication network. This controller has a unique feature that it does...

  11. Short term dynamic aperture with AC dipoles

    Mönig, Saskia; Persson, Tobias Hakan Bjorn; Coello De Portugal, Jaime; Langner, Andy; Tomas, Rogelio; CERN. Geneva. ATS Department

    2015-01-01

    The dynamic aperture of an accelerator is determined by its non-linear components and errors. Control of the dynamic aperture is important for a good understanding and operation of the accelerator. The AC dipole, installed in the LHC for the diagnostic of linear and non-linear optics, could serve as a tool for the determination of the dynamic aperture. However, since the AC dipole itself modifies the non-linear dynamics, the dynamic aperture with and without AC dipole are expected to differ. The effect of the AC dipole on the dynamic aperture is studied within this note.

  12. ac electroosmosis in rectangular microchannels.

    Campisi, Michele; Accoto, Dino; Dario, Paolo

    2005-11-22

    Motivated by the growing interest in ac electroosmosis as a reliable no moving parts strategy to control fluid motion in microfluidic devices for biomedical applications, such as lab-on-a-chip, we study transient and steady-state electrokinetic phenomena (electroosmosis and streaming currents) in infinitely extended rectangular charged microchannels. With the aid of Fourier series and Laplace transforms we provide a general formal solution of the problem, which is used to study the time-dependent response to sudden ac applied voltage differences in case of finite electric double layer. The Debye-Huckel approximation has been adopted to allow for an algebraic solution of the Poisson-Boltzmann problem in Fourier space. We obtain the expressions of flow velocity profiles, flow rates, streaming currents, as well as expressions of the complex hydraulic and electrokinetic conductances. We analyze in detail the dependence of the electrokinetic conductance on the extension of linear dimensions relative to the Debye length, with an eye on finite electric double layer effects. PMID:16351310

  13. DESARROLLO RURAL A.C.

    Alfredo Aguilar Valdés

    2015-01-01

    Full Text Available El objetivo de este trabajo fue analizar el diagnostico situacional de una Empresa de Servicios Profesionales en el caso de: Instituto de Promoción Para el Desarrollo Rural A.C., a través de la Metodología “UALAE” así como la oportunidad que como empresa presenta. Este estudio se realizó en el municipio de Saltillo, Coahuila, México. Adoptó esta Metodología UALAE y se difundió su opinión. El Instituto de Promoción Para el Desarrollo Rural A.C., está formado por profesionistas y productores cuya finalidad es la de contribuir al desarrollo del medio rural con proyectos de viabilidad técnica, económica y social, sobre la base de necesidades reales y al aprovechamiento sustentable del potencial de los recursos naturales. Su buen funcionamiento es indispensable e importante para el desarrollo de los productores agropecuarios principalmente, debido a que se ven muy beneficiados con todos los servicios que se les brinda, se han logrado buenos proyectos, buenas capacitaciones y un gran crecimiento de sus productos. Mediante el proceso de asistencia técnica a organizaciones de productores, se induce la formulación adecuada de proyectos viables desde el punto visto del mercado, la rentabilidad económica, las tecnologías disponibles y de la organización social.

  14. 基于VME总线的三相无环流AC/AC变频控制系统%Development of VME Bus Based Control System on Three-phase Cycloconverter Without Circulating Current

    罗(韡); 姜建国; 徐亚军

    2011-01-01

    介绍了三相无环流AC/AC变频控制系统的控制原理及其基于VME总线的控制系统硬件和软件设计,并给出硬件实验平台的调试结果.三相AC/AC变频器能输出频率为0~15 Hz电流和电压波形,电流无环流死区时间小于2ms,实验结果表明所研制的基于VME总线的三相AC/AC变频控制系统具有较高控制精度和实时性.

  15. Doses de nitrogênio no acúmulo de nitrato e na produção da alface em hidroponia Nitrogen rates on nitrate accumulation and lettuce production in hydroponic system

    Mônica LA Pôrto

    2012-09-01

    Full Text Available A produção da alface em hidroponia apresenta crescente expansão no Brasil, mas ainda ocorrem problemas de qualidade e risco de acúmulo de nitrato. O objetivo desse trabalho foi avaliar a produção da alface (cv. Elba e acúmulo de nitrato em hidroponia em função de níveis crescentes de N na solução nutritiva. Plantas de alface foram cultivadas em estufa telada da UFPB em Areia (PB, em solução nutritiva que continha níveis crescentes de N (11, 13, 15, 17, 19 e 21 mmol L-1 por 25 dias. O delineamento utilizado foi inteiramente casualizado com quatro repetições. Foram avaliadas a produção total (PTT, produção comercial (PCM e os teores de nitrato na matéria fresca da raiz, caule e folhas da alface. Não foram verificados efeitos significativos do incremento dos níveis de N na solução sobre a PTT e PCM, sendo obtidos valores médios de 357,3 e 352,5 g/planta, respectivamente. A elevação dos níveis de N em solução resultou em incrementos nos teores de nitrato em todas as partes da alface, obtendo-se na dose máxima teores de 659, 623 e 615 mg kg-1 de matéria fresca, para raiz, caule e folhas, respectivamente. Os máximos teores foliares de nitrato obtidos se encontraram abaixo do limite de risco para saúde humana.Lettuce production in hydroponic system presents growing expansion in Brazil, but still there are problems of quality and risk of nitrate accumulation. This work was carried out to evaluate the lettuce production and nitrate accumulation in hydroponic system depending on the increasing levels of nitrogen in the nutrient solution. The experiment was conducted in greenhouse of the Universidade Federal da Paraíba, Brazil. The lettuce plants were grown in nutrient solution containing increasing levels of N (11, 13, 15, 17, 19 and 21 mmol L-1 during a 25-day period. An entirely randomized design with four replications was used. Plant total yield (PTT, plant commercial yield (PCM and nitrate contents in the fresh

  16. Relationship Between DC Current Distribution and Multilayer Soil Parameters in AC-DC Interconnected Power System%交直流互联系统直流电流分布与多层土壤参数的关系

    任志超; 胡灿; 甄威; 吴超; 张一坤; 吴广宁

    2012-01-01

    分层土壤参数是影响交直流互联系统直流电流分布的重要因素.将各层土壤的电阻率及厚度作为自变量,变压器中性点的直流电流作为因变量,利用二元函数的三维曲面及等值线来描述变压器中性点直流电流与各层土壤参数的关系;基于此,研究多层土壤参数同时变化时,交直流互联系统直流电流分布与地理位置的关系.结果表明:变压器中性点的直流电流分别与第1层土壤电阻率比厚度、第2层土壤电阻率乘厚度、第3层土壤电阻率比厚度相关;当第1层土壤电阻率取最小值、厚度取最大值,第2~4层土壤电阻率全部取最大值、厚度全部取最小值时,各站点变压器中性点的直流电流相对较大;距离接地极越远,不同站点变压器中性点的直流电流差距越小.%Stratified soil parameters are an important factor in affecting the DC current distribution in the AC-DC interconnected power system. The resistivity and thickness of each soil layer taken as independent variables and the DC current of transformer neutral point regarded as dependent variable, the 3D surface and isoline of the binary function were used to describe the relationship between the DC current of transformer neutral point and the parameter of each soil layer. And then, the relationship between the DC current distribution in the AC-DC interconnected power system and the geographical position was studied, with multilayer soil parameters changing at the same time. The results showed that the DC current of transformer neutral point was related to the ratio of resistivity to thickness of the first layer, the product of resistivity and thickness of the second layer, and the ratio of resistivity to thickness of the third layer, respectively. The DC current of each substation was relatively larger when the resistivity and thickness of the first layer took the minimum and maximum value, and those of the second, third and fourth

  17. AcEST: BP920845 [AcEST

    Full Text Available 45|Adiantum capillus-veneris mRNA, clone: YMU001_000142_D08. (514 letters) Database: uniprot_sprot.fasta 412,525 seq...P7 OS=Magnapor... 33 1.0 sp|Q7VF68|SYH_HELHP Histidyl-tRNA synthetase OS=Helicobacter hep... 31 3.8 sp|P1305...90 FTGFLVLHSEPRQQPQVDL 1608 >sp|A4QX49|DBP7_MAGGR ATP-dependent RNA helicase DBP7 OS=Magnaporthe grise...T PT VT+H + T+ AC+ A+TT+ H H Sbjct: 481 PPKETKPTK------PVTNHTESTVGKACYITSAANTTITLHKLH 519 >sp|Q7VF68|SYH_HELHP His...rot_trembl.fasta 7,341,751 sequences; 2,391,615,440 total letters Searching.................................

  18. AcEST: DK960083 [AcEST

    Full Text Available ome P450 71D7 OS=Solanum chacoense ... 96 1e-19 sp|Q9SAB6|C71AI_ARATH Cytochrome ...... 96 2e-19 sp|P93530|C71D6_SOLCH Cytochrome P450 71D6 OS=Solanum chacoense ... 94 5e-19 sp|Q9T0K2|C71AK_AR... paten... 176 1e-42 tr|Q9AXP9|Q9AXP9_POPJC Cinnamate 4-hydroxylase OS=Populus jackii... 176 2e-42 tr|Q40907|Q40907_POPKI Cinnamic ac...8 KVVQQSRGAWEDEALRVIQDLKA 160 >tr|Q9AXP9|Q9AXP9_POPJC Cinnamate 4-hydroxylase OS=Populus jackii GN=C4H PE=2 ...e-42 tr|A9PBZ7|A9PBZ7_POPTR Putative uncharacterized protein OS=Popul... 176 2e-4

  19. AcEST: DK955376 [AcEST

    Full Text Available TST39A01NGRL0022_O23 611 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0022_O23. 5' end seq ... LMDETRAAGIKL 210 Query: 602 AIC 610 A+C Sbjct: 211 AVC ... 213 >tr|A9SM81|A9SM81_PHYPA Predicted protein OS=P ... C 610 VLELMD A+ KGLKVA+C Sbjct: 196 VLELMDAAREKGLKVAVC ... 213 >tr|Q8L7U1|Q8L7U1_ARATH AT4g39970/T5J17_140 OS ... LKVAIC 610 LMDEA+A G K+A+C Sbjct: 182 RLMDEAKAAGKKLAVC ... 197 >tr|Q680K2|Q680K2_ARATH MRNA, complete cds, cl ... LKVAIC 610 LMDEA+A G K+A+C Sbjct: 182 RLMDEAKAAGKKLAVC ... 197 >tr|Q8LAS1|Q8LAS1_ARATH Putative uncharacteriz ...

  20. AcEST: BP913416 [AcEST

    Full Text Available GCATGTAGTTTGGA CAGAGATG ■■Homology search results ■■ - Swiss-Prot (release 56.9) Link to BlastX Result : Swi...AC_BACFN Uronate isomerase OS=Bacteroides fragilis (... 30 4.5 sp|Q3ITT7|SYA_NATPD Alanyl-tRNA synthetase OS=Natronomonas phar...C++ N IP+ M C Sbjct: 417 LSYPRHEYFRRTLCNLLGCDVENGEIPLSEMERVC 451 >sp|Q3ITT7|SYA_NATPD Alanyl-tRNA synthetase OS=Natronomonas phar...ng, Webb Miller, and David J. Lipman (1997), Gapped BLAST and PSI-BLAST: a new generation of protein database searc...148,809,765 total letters Searching..................................................done Score E Sequences

  1. AcEST: DK947388 [AcEST

    Full Text Available Lipman (1997), Gapped BLAST and PSI-BLAST: a new generation of protein database search programs, Nucleic Ac...ids Res. 25:3389-3402. Query= DK947388|Adiantum capillus-veneris mRNA, clone: YMU02A01NGRL0015_L18, 5' (587 letters) Databa... generation of protein database search programs, Nucleic Acids Res. 25:3389-3402. Query= DK947388|Adiantum c...apillus-veneris mRNA, clone: YMU02A01NGRL0015_L18, 5' (587 letters) Database: uniprot_trembl.fasta...-ribosylation factor 1 OS=Salix bakko GN... 268 1e-71 sp|P49076|ARF_MAIZE ADP-ribosylation factor OS=Zea may

  2. AcEST: BP916217 [AcEST

    Full Text Available inase kinase 7-interacting protein 3 OS=Mus musculus Align length 119 Score (bit) 35.0 E-value 0.16 Report B...visiae GN... 30 6.8 >sp|Q571K4|TAB3_MOUSE Mitogen-activated protein kinase kinase kinase 7-interacting protein 3 OS=Mus musculus...protein kinase kinase kinase 7 interacting protein 3 OS=Mus musculus GN=Map3k7ip3 PE=2 SV=1 Length = 716 Sco...(3)malignant brain tumor-like 2 prot... 31 2.3 sp|P33234|ADIY_ECOLI HTH-type transcriptional regulator adiY ...ZZC3_PSEU2 Membrane protein, putative OS=Pseudomonas... 35 2.5 tr|Q5U7D5|Q5U7D5_9BACI OpuAC OS=Halobacillus trueperi GN=opu

  3. AcEST: DK953324 [AcEST

    Full Text Available |LSRR_PHOLL Transcriptional regulator lsrR OS=Photorhab... 30 6.1 sp|A0JY64|ATPB_ARTS2 ATP synthase subunit beta OS=Arthroba...cter s... 30 6.1 sp|A1R7V3|ATPB_ARTAT ATP synthase subunit beta OS=Arthroba...ATP synthase subunit beta OS=Arthrobacter sp. (strain FB24) GN=atpD PE=3 SV=1 Len...KD 372 Query: 311 HLHFTHRGKQRL 346 H + R KQ L Sbjct: 373 HYNTAVRVKQIL 384 >sp|A1R7V3|ATPB_ARTAT ATP synthase subunit beta OS=Arthroba...T and PSI-BLAST: a new generation of protein database search programs, Nucleic Ac

  4. AcEST: DK945049 [AcEST

    Full Text Available R 148 >sp|Q9X5X3|ATCU_SINMW Copper-transporting P-type ATPase OS=Sinorhizobium medicae (strain WSM419) GN=ac...|Q4EPP8|Q4EPP8_LISMO Heavy metal-binding protein OS=Listeria m... 34 3.2 tr|A6AST1|A6AST1_VIBHA Copper-trans..... 31 2.7 sp|Q4X0S7|DPH1_ASPFU Diphthamide biosynthesis protein 1 OS=Asper... 30 4.5 sp|A2VDJ0|T131L_HUMAN Transmembran...P58342|ATCU2_RHIME Copper-transporting ATPase 2 OS=Rhizobium meliloti Align length 75 Score (bit) 34.7 E-val...sophila ... 30 7.8 >sp|P58342|ATCU2_RHIME Copper-transporting ATPase 2 OS=Rhizobium me

  5. Operation and Control of Grid Connected Hybrid AC/DC Microgrid using various RES

    Kodanda Ram R B P U S B

    2014-10-01

    Full Text Available This paper proposes a Hybrid AC/DC Microgrid in alliance with Photo Voltaic (PV energy, Wind Energy and Proton Exchange Membrane (PEM Fuel cells. Microgrids are becoming increasingly attractive to the researchers because of the less greenhouse gases, low running cost, and flexibility to operate in connection with utility grid. The Hybrid AC/DC Microgrid constitutes independent AC and DC subgrids, where all the corresponding sources and loads are connected to their respective buses and these buses are interfaced using an interfacing converter. The Hybrid AC/DC Microgrid increases system efficiency by reducing the multiple reverse conversions involved in conventional RES integration to grid. A Small Hybrid AC/DC Microgrid in grid connected mode was modeled and simulated in MATLAB-SIMULINK environment. The simulation results proves the stable operation considering the uncertainty of generations and loads.

  6. Study on Dielectric Dissipation Factor of GVPI AC Motor Stator Winding without Anti-corona System%GVPI交流电动机无防晕系统定子绕组的介质损耗因数研究

    胡波; 梁智明; 漆临生; 黄绍波; 任东滨; 周进; 刘雁

    2014-01-01

    通过对GVPI高压交流电动机无防晕系统的定子绕组线圈槽部与端部结构进行分析,建立了相应的电路模型,对定子绕组的介质损耗因数(tanδ)与电容(C)随施加电压(U)的变化关系进行了测试及分析,并将绕组介质损耗因数的理论计算值与实测值进行比较。结果表明:定子绕组的介质损耗因数及其增量与电容及其增量成正比,同时由模型电路计算的介质损耗因数与试验实测值基本一致。%By analyzing insulation structure of global vacuum pressure impregnation(GVPI) AC motor sta-tor winding without anti-corona system, we built a corresponding circuit model to test the change of di-electric dissipation factor(tanδ) and capacitance of stator winding with the voltage, and the calculation val-ue of dielectric dissipation factor of stator winding was compared with the test value. The results show that the dielectric dissipation factor and its increment of stator winding are proportional to the capacitance and its increment. The calculation value of dielectric dissipation factor is consistent to the test value.

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

    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

  8. Assessing the allelotypic effect of two aminocyclopropane carboxylic acid synthase-encoding genes MdACS1 and MdACS3a on fruit ethylene production and softening in Malus

    Dougherty, Laura; Zhu, Yuandi; Xu, Kenong

    2016-01-01

    Phytohormone ethylene largely determines apple fruit shelf life and storability. Previous studies demonstrated that MdACS1 and MdACS3a, which encode 1-aminocyclopropane-1-carboxylic acid synthases (ACS), are crucial in apple fruit ethylene production. MdACS1 is well-known to be intimately involved in the climacteric ethylene burst in fruit ripening, while MdACS3a has been regarded a main regulator for ethylene production transition from system 1 (during fruit development) to system 2 (during fruit ripening). However, MdACS3a was also shown to have limited roles in initiating the ripening process lately. To better assess their roles, fruit ethylene production and softening were evaluated at five time points during a 20-day post-harvest period in 97 Malus accessions and in 34 progeny from 2 controlled crosses. Allelotyping was accomplished using an existing marker (ACS1) for MdACS1 and two markers (CAPS866 and CAPS870) developed here to specifically detect the two null alleles (ACS3a-G289V and Mdacs3a) of MdACS3a. In total, 952 Malus accessions were allelotyped with the three markers. The major findings included: The effect of MdACS1 was significant on fruit ethylene production and softening while that of MdACS3a was less detectable; allele MdACS1–2 was significantly associated with low ethylene and slow softening; under the same background of the MdACS1 allelotypes, null allele Mdacs3a (not ACS3a-G289V) could confer a significant delay of ethylene peak; alleles MdACS1–2 and Mdacs3a (excluding ACS3a-G289V) were highly enriched in M. domestica and M. hybrid when compared with those in M. sieversii. These findings are of practical implications in developing apples of low and delayed ethylene profiles by utilizing the beneficial alleles MdACS1-2 and Mdacs3a. PMID:27231553

  9. Water calorimetry with thermistor bridge operated in DC and AC mode: comparative results

    Guerra, A.S.; Laitano, R.F.; Petrocchi, A. [Ist. Nazionale di Metrologia delle Radiazioni Ionizzanti, ENEA, Roma (Italy)

    1997-09-01

    An experimental study was carried out to find out the optimal conditions for measuring the output signal in a water calorimeter. To this end the thermistor bridge of the calorimeter was operated in AC and in DC mode, respectively. A comparative analysis of these two alternative methods was the made. In the AC mode measurement a lock-in amplifier based experimental assembly was used and compared to the more conventional system based on a high-sensitivty DC amplifier. The AC system resulted to be preferable as far as the short term and long term reproducibility is concerned. (orig.)

  10. Water calorimetry with thermistor bridge operated in DC and AC mode: comparative results

    An experimental study was carried out to find out the optimal conditions for measuring the output signal in a water calorimeter. To this end the thermistor bridge of the calorimeter was operated in AC and in DC mode, respectively. A comparative analysis of these two alternative methods was the made. In the AC mode measurement a lock-in amplifier based experimental assembly was used and compared to the more conventional system based on a high-sensitivty DC amplifier. The AC system resulted to be preferable as far as the short term and long term reproducibility is concerned. (orig.)

  11. Produção Arbórea e Animal em Sistema Silvipastoril com Acácia-negra (Acacia mearnsii Trees and Animal Production in a Silvipastoral System with Black Wattle (Acacia mearnsii

    Zelia Maria de Souza Castilhos

    2010-02-01

    Full Text Available

    Com o objetivo de avaliar o desempenho dos componentes arbóreo e animal em um sistema silvipastoril (SSP com acácia-negra (Acacia mearnsii De Wild e gramíneas perenes de verão, foi conduzido um trabalho em convênio com a empresa Seta S.A., na unidade da Fepagro em Tupanciretã, RS, no período de outubro de 1995 a maio de 2003. O delineamento experimental foi um bifatorial (espécie forrageira e densidade arbórea inteiramente casualizado, com duas repetições. As espécies forrageiras (EF avaliadas foram capim annoni (Eragrostis plana, braquiária (Brachiaria brizantha e capim gatton (Panicum maximum cv. Gatton nos quatro primeiros anos, e capim gatton, capim aruana (P. maximum cv. Aruana e capim pangola (Digitaria diversinervis para os demais anos. As densidades arbóreas (DA testadas foram de 1.667, 1.000, 833 e 500 árvores.ha-1. Com 1.667 árvores.ha-1 houve maior rendimento de madeira em todas as avaliações, não diferindo de 1.000 árvores/ha-1 a partir do quinto ano. A produtividade animal foi mais elevada em DA de 833 e 500 árvores.ha-1, sendo respectivamente 229 e 223 kg.ha-1 de peso vivo. Aos sete anos de implantação da acácia negra, o volume de madeira foi de 166; 143; 86 e 51 m3.ha-1, respectivamente, nas densidades arbóreas de 1.667; 1.000; 833 e 500 árvores.ha-1. Para que haja um equilíbrio entre produção arbórea e animal, SSPs com densidades arbóreas entre 1.000 e 833 árvores.ha-1 apresentam-se como alternativas viáveis para os produtores rurais.

     

    doi: 10.4336/2009.pfb.60.39

    A silvopastoral study consisting of black wattle (Acacia mearnsii De Wild and tropical perennial grasses was developed at the Fepagro Research Unity in Tupanciretã, RS, in collaboration with Seta Group, from October 1995 until May 2003, with the objective of evaluating trees and animal (beef cattle performances. The experiment was a bifactorial completely randomized design (forage specie and arboreal density with two

  12. Photovoltaic Inverter Controllers Seeking AC Optimal Power Flow Solutions

    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.

  13. Advanced reliability improvement of AC-modules (ARIA)

    The AC-module is a relatively new development in PV-system technology and offers significant advantages over conventional PV-systems with a central inverter : e.g. increased modularity, ease of installation and freedom of system design. The Netherlands and Switzerland have a leading position in the field of AC-modules, both in terms of technology and of commercial and large-scale application. An obstacle towards large-scale market introduction of AC-modules is that the reliability and operational lifetime of AC-modules and the integrated inverters in particular are not yet proven. Despite the advantages, no module-integrated inverter has yet achieved large scale introduction. The AC-modules will lower the barrier towards market penetration. But due to the great interest in the new AC-module technology there is the risk of introducing a not fully proven product. This may damage the image of PV-systems. To speed up the development and to improve the reliability, research institutes and PV-industry will address the aspects of reliability and operational lifetime of AC-modules. From field experiences we learn that in general the inverter is still the weakest point in PV-systems. The lifetime of inverters is an important factor on reliability. Some authors are indicating a lifetime of 1.5 years, whereas the field experiences in Germany and Switzerland have shown that for central inverter systems, an availability of 97% has been achieved in the last years. From this point of view it is highly desirable that the operational lifetime and reliability of PV-inverters and especially AC-modules is demonstrated/improved to make large scale use of PV a success. Module Integrated Inverters will most likely be used in modules in the power range between 100 and 300 Watt DC-power. These are modules with more than 100 cells in series, assuming that the module inverter will benefit from the higher voltage. Hot-spot is the phenomenon that can occur when one or more cells of a string

  14. 混合超级电容器AC/LiMn2O4体系的电化学性能%Study on the Electrochemical Performance of Hybrid Aqueous Electro-chemical Supercapacitor in AC/LiMn2O4 System

    毕文英; 王成扬

    2007-01-01

    AC/LiMnO4体系混合电容器进行研究,以活性炭(AC)为负极材料,尖晶石结构的LiMn2O4为正极材料,Li2SO4为电解液.该体系的原理与锂离子电池很相似,从本质上说属于一种特殊的锂离子电池.改变正负极的质量配比,根据其电化学性能确定了该体系最佳的正负极质量配比.对不同电解液浓度的电容器进行不同电流密度充放电测试,发现电解液浓度增加,会使容量和大电流性能得到明显改善,极化电阻的增大会大大降低放电电压平台.实验表明该体系具有较高的能量密度和功率密度,同时保持了良好的循环性能.

  15. Distribuição do sistema radicular de árvores de acáia-negra oriundas de mudas produzidas em diferentes recipientes Influence of seedling production method on the root system distribution of black wattle trees

    Aline Fagote Paulino

    2003-10-01

    Full Text Available O objetivo deste trabalho foi estudar a distribuição do sistema radicular de árvores de acácia-negra (Acacia mearnsii com 3 anos de idade, provenientes de mudas formadas em diferentes recipientes e instaladas em um Argissolo no Rio Grande do Sul. Os recipientes utilizados foram: laminado, tubete redondo e bandeja de isopor. As avaliações da distribuição das raízes foram feitas pelo método da parede do perfil até 1 m de profundidade, na linha e na entrelinha de plantio. Foram feitas, também, análises físicas do solo: densidade, porosidade total e distribuição de poros. O recipiente usado na formação da muda influenciou o crescimento do sistema radicular da planta no campo. O laminado de madeira apresentou-se superior ao tubete quanto ao comprimento de raízes nas linhas de plantio. As raízes cresceram melhor nas linhas de plantio, onde as condições de densidade e porosidade do solo se encontravam mais adequadas.The purpose of this study was to evaluate the root system distribution of three-year-old black wattle (Acacia mearnsii trees. The plants were originated from seedlings grown in different containers and planted in an Argisol in the state of Rio Grande do Sul, Brazil. The containers used for seedling production were: wood laminated pots, round plastic tubettes and styrofoam trays. The evaluations were carried out using the trench profile method up to 1 m depth on tree rows and inter-rows. The following soil analyses were also carried out: bulk density, total porosity and pore distribution. The type of container used influenced the development of the root system of trees on the field. Wood laminated pots were better than the round tubettes for root length in the tree rows. The roots developed better on the tree rows where soil density and porosity conditions were more adequate.

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

    M.A INAYATHULLAAH,; Dr. R. Anita

    2010-01-01

    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 ...

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

    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.

  18. The effect of DC superimposed AC Voltage on Partial Discharges in Dielectric Bounded Cavities

    Olsen, Pål Keim; Mauseth, Frank; Ildstad, Erling

    2014-01-01

    Voltage source converters is used in HVDC stations in offshore HVDC transmission systems, between the AC and DC power grid. The AC ripple voltage on the DC side of the HVDC stations can be in the range of 1-10 % of the nominal DC voltage, depending on the size of the filter employed. For offshore HVDC grids, there is a drive to use polymeric insulated cables on the DC side. This work investigates how an AC voltage at power frequency superimposed on DC voltage influence the partial discharge m...

  19. MD 349: Impedance Localization with AC-dipole

    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.

  20. A Linear-Programming Approximation of AC Power Flows

    Coffrin, Carleton; Van Hentenryck, Pascal

    2012-01-01

    Linear active-power-only DC power flow approximations are pervasive in the planning and control of power systems. However, these approximations fail to capture reactive power and voltage magnitudes, both of which are necessary in many applications to ensure voltage stability and AC power flow feasibility. This paper proposes linear-programming models (the LPAC models) that incorporate reactive power and voltage magnitudes in a linear power flow approximation. The LPAC models are built on a co...

  1. AC Power Local Network with Multiple Power Routers

    Ryo Takahashi; Yutaro Kitamori; Takashi Hikihara

    2013-01-01

    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 circui...

  2. Characterization of AcMNPV with a deletion of ac69 gene

    Jianhao Ke

    2011-07-01

    Full Text Available ORF69 (Ac69 of Autographa californica multiple nucleopolyhedrovirus (AcMNPV is conserved in some baculovirus genomes. Although it has been shown that Ac69 has cap 0-dependent methyltransferase activity and is not required for budded virus production in Spodoptera frugiperda Sf-9 cells, its role in occlusion-derived virus synthesis and virus oral infectivity is not known. This paper describes generation of an ac69 knockout AcMNPV bacmid mutant and analyses of the influence of ac69 deletion on the viral infectivity in Sf-9 cells and Trichoplusia ni larvae so as to investigate the role of ac69 in the viral life cycle. Results indicated that ac69 deletion has little effect on the production rates and morphogenesis of budded virus and occlusion-derived virus in Sf-9 cells. In addition, animal experiment revealed that the deletion mutant did not affect AcMNPV infectivity for Trichoplusia ni larvae in LD50 and LT50 bioassay when administered orally. These results suggest that ac69 may be dispensable for viral infectivity both in vitro and in vivo.

  3. Noise reduction in AC-coupled amplifiers

    Serrano Finetti, Roberto Ernesto; Pallàs Areny, Ramon

    2014-01-01

    AC-coupled amplifiers are noisier than dc-coupled amplifiers because of the thermal noise of the resistor(s) in the ac-coupling network and the increased contribution of the amplifier input noise current i(n). Both contributions, however, diminish if the corner frequency f(c) of the high-pass filter observed by the signal is lowered, the cost being a longer transient response. At the same time, the presence of large resistors in the ac-coupling network suggests that the use of FET-input ampli...

  4. Improved transistorized AC motor controller for battery powered urban electric passenger vehicles

    Peak, S. C.

    1982-01-01

    An ac motor controller for an induction motor electric vehicle drive system was designed, fabricated, tested, evaluated, and cost analyzed. A vehicle performance analysis was done to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of ac motor and ac controller requirements. The power inverter is a three-phase bridge using power Darlington transistors. The induction motor was optimized for use with an inverter power source. The drive system has a constant torque output to base motor speed and a constant horsepower output to maximum speed. A gear shifting transmission is not required. The ac controller was scaled from the base 20 hp (41 hp peak) at 108 volts dec to an expanded horsepower and battery voltage range. Motor reversal was accomplished by electronic reversal of the inverter phase sequence. The ac controller can also be used as a boost chopper battery charger. The drive system was tested on a dynamometer and results are presented. The current-controlled pulse width modulation control scheme yielded improved motor current waveforms. The ac controller favors a higher system voltage.

  5. DIAGNOSTIC FEATURES RESEARCH OF AC ELECTRIC POINT MOTORS

    S. YU. Buryak

    2014-05-01

    Full Text Available Purpose.Considerable responsibility for safety of operation rests on signal telephone and telegraph department of railway. One of the most attackable nodes (both automation systems, and railway in whole is track switches. The aim of this investigation is developing such system for monitoring and diagnostics of track switches, which would fully meet the requirements of modern conditions of high-speed motion and heavy trains and producing diagnostics, collection and systematization of data in an automated way. Methodology. In order to achieve the desired objectives research of a structure and the operating principle description of the switch electric drive, sequence of triggering its main units were carried out. The operating characteristics and settings, operating conditions, the causes of failures in the work, andrequirements for electric drives technology and their service were considered and analyzed. Basic analysis principles of dependence of nature of the changes the current waveform, which flows in the working circuit of AC electric point motor were determined. Technical implementation of the monitoring and diagnosing system the state of AC electric point motors was carried out. Findings. Signals taken from serviceable and defective electric turnouts were researched. Originality. Identified a strong interconnectionbetween the technical condition of the track switchand curve shape that describes the current in the circuit of AC electric point motor during operation which is based on the research processes that have influence on it during operation. Practical value. Shown the principles of the technical approach to the transition from scheduled preventive maintenance to maintenance of real condition for a more objective assessment and thus more rapid response to emerging or failures when they occur gradually, damages and any other shortcomings in the work track switch AC drives.

  6. Broken space-time symmetries and mechanisms of rectification of ac fields by nonlinear (non)adiabatic response

    Denisov, S.; Flach, S.; Ovchinnikov, A. A.;

    2002-01-01

    We consider low-dimensional dynamical systems exposed to a heat bath and to additional ac fields. The presence of these ac fields may lead to a breaking of certain spatial or temporal symmetries, which in turn cause nonzero averages of relevant observables. Nonlinear (non)adiabatic response...

  7. Crossover of the Hall-voltage distribution in AC quantum Hall effect

    Akera, H.

    2011-01-01

    The distribution of the Hall voltage induced by low-frequency AC current is studied theoretically in the incoherent linear transport of quantum Hall systems. It is shown that the Hall-voltage distribution makes a crossover from the uniform distribution to a concentrated-near-edges distribution as the frequency is increased or the diagonal conductivity is decreased. This crossover is also reflected in the frequency dependence of AC magnetoresistance.

  8. Crossover of the Hall-voltage distribution in AC quantum Hall effect

    Akera, Hiroshi

    2009-01-01

    The distribution of the Hall voltage induced by low-frequency AC current is studied theoretically in the incoherent linear transport of quantum Hall systems. It is shown that the Hall-voltage distribution makes a crossover from the uniform distribution to a concentrated-near-edges distribution as the frequency is increased or the diagonal conductivity is decreased. This crossover is also reflected in the frequency dependence of AC magnetoresistance.

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

    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)

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

    Klumpner, Christian; Blaabjerg, Frede

    2004-01-01

    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......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...... to minimize the overall energy cost or in case of special applications, to improve the system redundancy. Also, having a generator that can simultaneously feed fractions of its power into multiple grids which are not coupled (different voltage, frequency, displacement angle) and continuously adjust...

  11. Towards an AC-MOT of CaF

    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. Image optimization procedures for the Fuji AC-1

    Freedman, Matthew T.; Mun, Seong K.; Pe, Einar V.; Lo, Shih-Chung B.; Nelson, Martha C.

    1993-06-01

    The Fuji AC-1 is a popular system for digital radiography with great potential, but for many the initial implementation of the system in a radiology service is frustrating experience for lack of effective support and a clear operational manual. Adjusting the image processing settings for site specific image optimization has been, for most users, difficult and confusing. The effect of each of the image processing parameters available on the Fuji AC-1 is not easily understood by users of the machine. The application manual that comes with the machine briefly defines the parameters and gives recommended settings for different types of examinations, but the manual does not provide the user with adequate information or a suggested method to allow the user to easily optimize the image for that user's site. This paper defines in more precise terms the meaning of the various parameters and suggests a method of procedure to optimize the parameters to each radiologists preference. The results are based on experiments and measurements we performed with a Fuji AC-1 +. This information should assist the radiologist to use a more systematic method of image quality improvement rather than the somewhat random trial and error process that current users have described.

  13. Transport AC losses in YBCO coated conductors

    Majoros, M [Ohio State University, Columbus, OH 43210 (United States); Ye, L [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Velichko, A V [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Coombs, T A [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Sumption, M D [Ohio State University, Columbus, OH 43210 (United States); Collings, E W [Ohio State University, Columbus, OH 43210 (United States)

    2007-09-15

    Transport AC loss measurements have been made on YBCO-coated conductors prepared on two different substrate templates-RABiTS (rolling-assisted biaxially textured substrate) and IBAD (ion-beam-assisted deposition). RABiTS samples show higher losses compared with the theoretical values obtained from the critical state model, with constant critical current density, at currents lower than the critical current. An origin of this extra AC loss was demonstrated experimentally by comparison of the AC loss of two samples with different I-V curves. Despite a difference in I-V curves and in the critical currents, their measured losses, as well as the normalized losses, were practically the same. However, the functional dependence of the losses was affected by the ferromagnetic substrate. An influence of the presence of a ferromagnetic substrate on transport AC losses in YBCO film was calculated numerically by the finite element method. The presence of a ferromagnetic substrate increases transport AC losses in YBCO films depending on its relative magnetic permeability. The two loss contributions-transport AC loss in YBCO films and ferromagnetic loss in the substrate-cannot be considered as mutually independent.

  14. A decomposition method for network-constrained unit commitment with AC power flow constraints

    To meet the increasingly high requirement of smart grid operations, considering AC power flow constraints in the NCUC (network-constrained unit commitment) is of great significance in terms of both security and economy. This paper proposes a decomposition method to solve NCUC with AC power flow constraints. With conic approximations of the AC power flow equations, the master problem is formulated as a MISOCP (mixed integer second-order cone programming) model. The key advantage of this model is that the active power and reactive power are co-optimised, and the transmission losses are considered. With the AC optimal power flow model, the AC feasibility of the UC result of the master problem is checked in subproblems. If infeasibility is detected, feedback constraints are generated based on the sensitivity of bus voltages to a change in the unit reactive power generation. They are then introduced into the master problem in the next iteration until all AC violations are eliminated. A 6-bus system, a modified IEEE 30-bus system and the IEEE 118-bus system are used to validate the performance of the proposed method, which provides a satisfactory solution with approximately 44-fold greater computational efficiency. - Highlights: • A decomposition method is proposed to solve the NCUC with AC power flow constraints • The master problem considers active power, reactive power and transmission losses. • OPF-based subproblems check the AC feasibility using parallel computing techniques. • An effective feedback constraint interacts between the master problem and subproblem. • Computational efficiency is significantly improved with satisfactory accuracy

  15. Power Balance Control in an AC/DC/AC Converter for Regenerative Braking in a Two-Voltage-Level Flywheel-Based Driveline

    Janaína G. Oliveira

    2011-01-01

    Full Text Available The integration of a flywheel as a power handling can increase the energy storage capacity and reduce the number of battery charge/discharge cycles. Furthermore, the ability of recovering energy of the vehicle during breaking can increase the system efficiency. The flywheel-based all-electric driveline investigated here has its novelty in the use of a double-wound flywheel motor/generator, which divides the system in two different voltage levels, enhancing the efficiency of the electric driveline. The connection of two AC electrical machines (i.e., the flywheel and the wheel motor with different and variable operation frequency is challenging. A power matching control applied to an AC/DC/AC converter has been implemented. The AC/DC/AC converter regenerates the electric power converted during braking to the flywheel machine, used here as power handling device. By controlling the power balance, the same hardware can be used for acceleration and braking, providing the reduction of harmonics and robust response. A simulation of the complete system during braking mode has been performed both in Matlab and Simulink, and their results have been compared. The functionality of the proposed control has been shown and discussed, with full regeneration achieved. A round-trip efficiency (wheel to wheel higher than 80% has been obtained.

  16. AcEST: DK957576 [AcEST

    Full Text Available CSU Iron-uptake system permease protein feuC OS... 30 7.6 sp|P21409|FBPB_SERMA Fe(3+)-transport system perme...e system permease protein feuC OS=Bacillus subtilis GN=feuC PE=1 SV=2 Length = 394 Score = 30.4 bits (67), E

  17. ISTTOK upgrade towards AC and remote operation

    ISTTOK has performed one of the earliest experiments of AC tokamak operation showing that long discharges could be produced merely with inductive current drive. However, due to the design of the machine, the data acquisition system and the power supplies, a limit of 250 ms (six times the nominal forward shot duration) is currently imposed.In this paper the relevant constrains to attain current operation up to the limit of the stable toroidal magnetic field (3s) are discussed and the work being carried out to achieve this goal is presented.The conditions that shall be accomplished are: (i) removing the power deposited on the limiters; (ii) density control through gas puffing and monitoring the recycling from the walls; (iii) assessment of the free magnetic flux available on the iron core (Wmax=0.2 Vs); (iv) reformulation of the data acquisition system towards an event driven philosophy maintaining the actual distributed architecture but allowing a real-time control; (v) active control of the equilibrium magnetic fields implementing a digital plasma position estimator and actuator through new power supplies for the poloidal magnetic fields. As a new high level software was needed to implement all this features, the ISTTOK data acquisition system and control has been totally redesigned in JAVA/SQL database technology and time stamps events were adopted to catalogue the data. This software has been design keeping in mind the needs for remote participation and operation of the machine. Therefore, a cooperative environment has been implemented where several persons can be connected together to the platform, programming their own devices and exchanging knowledge or opinions through an embedded chat

  18. ISTTOK upgrade towards AC and remote operation

    Fernandes, H.; Silva, C.; Carvalho, B.; Sousa, J.; Valcárcel, D.; Neto, A.; Fortunato, J.; Carvalho, I.; Varandas, C. A. F.

    2006-12-01

    ISTTOK has performed one of the earliest experiments of AC tokamak operation showing that long discharges could be produced merely with inductive current drive. However, due to the design of the machine, the data acquisition system and the power supplies, a limit of 250 ms (six times the nominal forward shot duration) is currently imposed. In this paper the relevant constrains to attain current operation up to the limit of the stable toroidal magnetic field (3s) are discussed and the work being carried out to achieve this goal is presented. The conditions that shall be accomplished are: (i) removing the power deposited on the limiters; (ii) density control through gas puffing and monitoring the recycling from the walls; (iii) assessment of the free magnetic flux available on the iron core (Wmax=0.2 Vs); (iv) reformulation of the data acquisition system towards an event driven philosophy maintaining the actual distributed architecture but allowing a real-time control; (v) active control of the equilibrium magnetic fields implementing a digital plasma position estimator and actuator through new power supplies for the poloidal magnetic fields. As a new high level software was needed to implement all this features, the ISTTOK data acquisition system and control has been totally redesigned in JAVA/SQL database technology and time stamps events were adopted to catalogue the data. This software has been design keeping in mind the needs for remote participation and operation of the machine. Therefore, a cooperative environment has been implemented where several persons can be connected together to the platform, programming their own devices and exchanging knowledge or opinions through an embedded chat.

  19. Power flow analysis for droop controlled LV hybrid AC-DC microgrids with virtual impedance

    Li, Chendan; Chaudhary, Sanjay; Vasquez, Juan Carlos;

    2014-01-01

    The AC-DC hybrid microgrid is an effective form of utilizing different energy resources and the analysis of this system requires a proper power flow algorithm. This paper proposes a suitable power flow algorithm for LV hybrid AC-DC microgrid based on droop control and virtual impedance. Droop and...... algorithm makes it a potential method for planning, dispatching and operation of droop controlled LV hybrid AC-DC....... virtual impedance concepts for AC network, DC network and interlinking converter are reviewed so as to model it in the power flow analysis. The validation of the algorithm is verified by comparing it with steady state results from detailed time domain simulation. The effectiveness of the proposed...

  20. Produção Arbórea e Animal em Sistema Silvipastoril com Acácia-negra (Acacia mearnsii) Trees and Animal Production in a Silvipastoral System with Black Wattle (Acacia mearnsii)

    Zelia Maria de Souza Castilhos; Raquel Santiago Barro; José Flores Savian; Henrique Rogério Branco do Amaral

    2010-01-01

    Com o objetivo de avaliar o desempenho dos componentes arbóreo e animal em um sistema silvipastoril (SSP) com acácia-negra (Acacia mearnsii De Wild) e gramíneas perenes de verão, foi conduzido um trabalho em convênio com a empresa Seta S.A., na unidade da Fepagro em Tupanciretã, RS, no período de outubro de 1995 a maio de 2003. O delineamento experimental foi um bifatorial (espécie forrageira e densidade arbórea) inteiramente casualizado, com duas repetições. As espécies forrageiras ...

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

    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

  2. AC Power Local Network with Multiple Power Routers

    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.

  3. AcEST: DK957474 [AcEST

    Full Text Available 0 7.5 sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS... 30 7.5 sp|P21409|FBPB_SERMA Fe(3+)...PPHGHPPHGPPPHGHPPHGPPP 399 >sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS=Bacillus subtilis GN=feu

  4. AcEST: DK961950 [AcEST

    Full Text Available 40411|FEUC_BACSU Iron-uptake system permease protein feuC OS... 30 7.9 sp|P21409|FBPB_SERMA Fe(3+)-transport...DWWASGE 44 >sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS=Bacillus subtilis GN=feuC PE=1

  5. AcEST: DK950911 [AcEST

    Full Text Available |Q6UXD1|HRCT1_HUMAN Histidine-rich carboxyl terminus protein 1... 31 5.5 sp|P40411|FEUC_BACSU Iron-uptake system permease protein feu...e system permease protein feuC OS=Bacillus subtilis GN=feuC PE=1 SV=2 Length = 394 Score = 30.4 bits (67), E

  6. AcEST: DK948648 [AcEST

    Full Text Available sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS... 30 8.9 sp|P21409|FBPB_SERMA Fe(3+)-tran...AGYDWWASGE 44 >sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS=Bacillus subtilis GN=feuC PE

  7. AcEST: DK960274 [AcEST

    Full Text Available p|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS... 30 8.0 sp|P21409|FBPB_SERMA Fe(3+)-transp...EEVAGSSRTREQLVPRLGGRAGYDWWASGE 44 >sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS=Bacillus subtilis GN=feu

  8. AcEST: DK960462 [AcEST

    Full Text Available FEUC_BACSU Iron-uptake system permease protein feuC OS... 30 7.7 sp|P21409|FBPB_SERMA Fe(3+)-transport syste...EQLVPRLGGRAGYDWWASGE 44 >sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS=Bacillus subtilis GN=feu

  9. AcEST: DK949578 [AcEST

    Full Text Available .8 sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS... 30 8.8 sp|P21409|FBPB_SERMA Fe(3+)-tr...GGRAGYDWWASGE 44 >sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS=Bacillus subtilis GN=feuC

  10. AC losses in filamentary YBCO/hastelloy

    Full text: The AC hysteresis loss of a long YBCO thin-film superconducting strip in a perpendicular AC magnetic field can be reduced by subdividing the film into narrow parallel strips (filaments). The hysteresis loss depends on the film critical current density Jc, the film thickness d, the filament width 2a and the lateral spacing L between filaments as well as on the AC magnetic field amplitude Hm. In addition, if the film is deposited onto a YSZ/hastelloy substrate to form a flexible tape, eddy current loss occurs in the hastelloy metal. The eddy current loss depends on the resistivity p of the hastelloy, the width 2w and thickness dm of the hastelloy substrate as well as on the frequency f and amplitude Hm. We have calculated the hysteresis and eddy current losses as a function of Jc, d, 2a, L, p, w, dm, f, and Hm to find optimal design parameters for a YBCO/hastelloy tape. As the AC loss is related to the loss component X'' of the AC susceptibility, we have measured X'' at different frequencies f and amplitudes Hm for several filamentary designs of YBCO/hastelloy tapes and compared our experimental results with our model calculations

  11. AcEST: DK955628 [AcEST

    Full Text Available 0410|FEUB_BACSU Iron-uptake system permease protein feuB OS=Bacillus subtilis Align length 74 Score (bit) 32...bits) Value sp|P40410|FEUB_BACSU Iron-uptake system permease protein feuB OS... 3...in transport protein SEC24-2 OS=Sacch... 30 7.8 >sp|P40410|FEUB_BACSU Iron-uptake system permease protein feu...B OS=Bacillus subtilis GN=feuB PE=1 SV=1 Length = 334 Score = 32.0 bits (71), Expect = 2.7 Identities = 23/

  12. Micronutrientes no sistema solo-Pinus caribaea Morelet em plantios apresentando amarelecimento das acículas e morte de plantas Micronutrients in the soil-Pinus caribaea Morelet System with yellowing of the needles followed by senescence and death

    Roselene de Queiroz Chaves

    2003-12-01

    Full Text Available Com o objetivo de contribuir no diagnóstico de causas que têm levado à morte precoce de pinheiros, verificada após amarelecimento e necrose progressiva das acículas, foi desenvolvido este estudo em áreas de cerrado, no oeste de Minas Gerais. Foram comparadas árvores de Pinus caribaea Morelet das variedades caribaea e hondurensis, plantadas entre 1977-82. Em cada local de amostragem coletou-se material de 20 árvores, sendo 10 com acículas amarelecidas e 10 normais. Foram coletados acículas e tecidos do xilema e floema de raízes, nos quais foram analisados os teores de Fe, Mn, Zn, Cu e B. A classe de solo dos sítios de estudo é Latossolo Amarelo ácrico típico. As amostras foram coletadas nas profundidades: 0-5, 5-10, 10-20, 20-40, 40-60, 60-80, 80-100, 100-150, 150-200, 200-250 e 250-300 cm, nas quais foram analisados os teores trocáveis de Fe, Mn, Zn, Cu e B. Os teores de Fe, Zn, Cu e B não diferiram significativamente entre acículas verdes e amarelecidas, enquanto os teores de Mn foram significativamente inferiores nestas. Observou-se também que os teores de Mn foram maiores no xilema e menores nas acículas das plantas anormais, ocorrendo o inverso nas plantas normais. Os sintomas visuais, confirmados pelos resultados analíticos, revelam haver deficiência de manganês no sistema solo-planta estudado.This study was carried out to diagnose senescence and death of pine trees (Pinus caribaea Morelet, observed after yellowing and progressive necrosis of the needles in the Brazilian Savanna (Cerrado in Western Minas Gerais, Brazil. The varieties caribaea and hondurensis, planted between 1977 and 1982 were compared. Samples from twenty trees were collected from the three sites studied; ten with yellowing of the needles and ten without symptoms. From each tree, phloem tissue and xylem from root segments and needles were collected and the contents of Fe, Mn, Zn, Cu and B were analyzed. The soil is Yellow Latosol (Typic Acrustox

  13. Microwave-induced crystallization of AC/TiO{sub 2} for improving the performance of rhodamine B dye degradation

    Tian, Fei [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China); Wu, Zhansheng, E-mail: wuzhans@126.com [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China); Chen, Qiuyu; Yan, Yujun [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China); Cravotto, Giancarlo; Wu, Zhilin [Dipartimento di Scienza e Tecnologia del Farmaco, University of Turin, Torino 10125 (Italy)

    2015-10-01

    Graphical abstract: - Highlights: • Mixed phase titania coated with AC was obtained by microwave irradiation method. • The TiO{sub 2} nanoparticles were spherical and well distributed on the surface of AC. • The light absorption edges of AC/TiO{sub 2} showed red-shift compared to the pure TiO{sub 2}. • Higher surface and TiO{sub 2} content of AC/TiO{sub 2} could improve photocatalytic efficiency. - Abstract: Titanium dioxide (TiO{sub 2}) deposition on activated carbon (AC) is widely used for pollutant photodegradation. In this study, a simple and efficient method for preparing AC/TiO{sub 2} composites under microwave irradiation was developed for photocatalytic degradation of rhodamine B (RhB) under UV light. Results of X-ray diffraction, scanning electron microscopy, and transmission electron microscopy revealed that TiO{sub 2} nanoparticles are anatase and rutile, with a spherical shape and a particle size of 20–50 nm and are well distributed on the AC surface. The UV–vis spectrum of TiO{sub 2} coated on AC showed an evident red-shift and exhibited stronger optical absorption capacity than pure TiO{sub 2}. The AC/TiO{sub 2} nanoparticles prepared at a microwave power of 700 W for 15 min exhibited 98% efficiency in removing RhB dye under UV irradiation for 30 min. The high photocatalytic activity of AC/TiO{sub 2}-700 W could be mainly attributed to the high sorption capacity of the mesoporous carbon material and high TiO{sub 2} content, which could produce higher quantity of ·OH. This study provides a rapid synthesis technique to prepare AC/TiO{sub 2} and a novel method to improve photocatalytic efficiency via synergistic effect for other catalytic systems.

  14. High benefits approach for electrical energy conversion in electric vehicles from DC to PWM-AC without any generated harmonic

    Highlights: • Novel hybrid power source including AC feature for using in electric/hybrid vehicles. • Minimizing the energy loss in electric/hybrid vehicles by using the proposed system. • Suitable AC wave form for braking/accelerating purposes in electric/hybrid vehicles. • A novelty is that the harmonic generated by the added AC feature is really zero. • Another novelty is the capability of choosing arbitrary frequency for AC feature. - Abstract: This paper presents a novel hybrid power source, including a Li-ion battery together with an interface, which generates simultaneously electrical energy with the forms of both DC and AC for electric vehicles. A novel and high benefits approach is applied to convert the electrical energy of the Li-ion battery from DC form to single-phase symmetric pulse-width modulation (PWM)-AC form. Harmonic generation is one of the important problems when electrical energy is converted from DC to AC but there are not any generated harmonic during the DC/AC conversion using the proposed technique. The proposed system will be widely used in electric/hybrid vehicles because it has many benefits. Minimizing the energy loss (saving energy), no generated harmonic (it is really zero), the capability of arbitrary/necessary frequency selection for output AC voltage and the ability of long distance energy transmission are some novelties and advantages of the proposed system. The proposed hybrid power source including DC/AC PWM inverter is simulated in Proteus 6 software environment and a laboratory-based prototype of the hybrid power source is constructed to validate the theoretical and simulation results. Simulation and experimental results are presented to prove the superiority of the proposed hybrid power supply

  15. AcEST: DK958373 [AcEST

    Full Text Available d protein OS=Physcomitrella patens subsp. patens Align length 204 Score (bit) 115.0 E-value 2.0e-24 Repor...EVEACAKRLH 277 >sp|Q2PBM2|LSRC_PHOTE Autoinducer 2 import system permease protein lsrC OS=Photorhabdus tem...9A6|U496D_ORYSI UPF0496 protein 4 OS=Oryza sativa subsp. i... 45 3e-04 sp|Q2PBM2|LSRC_PHOTE Autoinducer 2 import system... permease protei... 40 0.009 sp|Q2PBL9|LSRC_PHOLU Autoinducer 2 import system permease protei... ...39 0.027 sp|Q7N2D8|LSRC_PHOLL Autoinducer 2 import system permease protei... 39 0.027 sp|A4TQL6|LSRC_YERPP Autoinducer 2 impor

  16. AcEST: DK958823 [AcEST

    Full Text Available p... 30 8.3 sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS... 30 8.3 sp|P21409|FBPB_SERMA ...: 7 RNRGLRELEEVAGSSRTREQLVPRLGGRAGYDWWASGE 44 >sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC... OS=Bacillus subtilis GN=feuC PE=1 SV=2 Length = 394 Score = 30.4 bits (67), Expect = 8.3 Identities = 9/27

  17. AcEST: DK962818 [AcEST

    Full Text Available domain-containing p... 30 8.8 sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS... 30 8.8 sp...Q P GR W SG+ Sbjct: 7 RNRGLRELEEVAGSSRTREQLVPRLGGRAGYDWWASGE 44 >sp|P40411|FEUC_BACSU Iron-uptake system permease protein feu...C OS=Bacillus subtilis GN=feuC PE=1 SV=2 Length = 394 Score = 30.4 bits (67), Expect = 8.8

  18. AcEST: DK949303 [AcEST

    Full Text Available ctin domain-containing p... 30 9.6 sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS... 30 9.... R +EQ P GR W SG+ Sbjct: 7 RNRGLRELEEVAGSSRTREQLVPRLGGRAGYDWWASGE 44 >sp|P40411|FEUC_BACSU Iron-uptake system permease protein feu...C OS=Bacillus subtilis GN=feuC PE=1 SV=2 Length = 394 Score = 30.4 bits (67), Expect =

  19. AcEST: DK963597 [AcEST

    Full Text Available ining p... 30 8.5 sp|P40411|FEUC_BACSU Iron-uptake system permease protein feuC OS... 30 8.5 sp|P21409|FBPB_... Sbjct: 7 RNRGLRELEEVAGSSRTREQLVPRLGGRAGYDWWASGE 44 >sp|P40411|FEUC_BACSU Iron-uptake system permease protein feu...C OS=Bacillus subtilis GN=feuC PE=1 SV=2 Length = 394 Score = 30.4 bits (67), Expect = 8.5 Identities =

  20. AcEST: BP920834 [AcEST

    Full Text Available YMU001_000142_C08 393 Adiantum capillus-veneris mRNA. clone: YMU001_000142_C08. BP920834 - Show ... e protein YOR044W O... 30 2.9 sp|Q3Z259|BTUC_SHISS Vitamin ... B12 import system permease protein ... 30 2.9 sp|Q ... 7C1M5|BTUC_SHIFL Vitamin ... B12 import system permease protein ... 30 2.9 sp|Q ...

  1. Linear ac transport in graphene semiconducting nanosystem with normal-metal electrodes

    Ye, En-Jia; Sun, Yun-Lei; Lan, Jin; Shi, Yi-Jian

    2016-03-01

    Linear ac transport properties are investigated in a graphene semiconducting nanosystem, with the effect of normal-metal electrodes taken into account. We use a tight-binding approach and ac transport theory to study the dc conductance and ac emittance in normal-metal/graphene (NG) and normal-metal/graphene/normal-metal (NGN) systems with armchair-edge graphene. We find that the resonant and semiconducting behaviors in NG and NGN systems are closely related to the spatial-resolved local density of states. Furthermore, features of the size-dependent emittances in the NGN system are investigated. The results suggest a positive correlation between the width and capacitive response, and the capacitive response is robust as the size of the system increases proportionally.

  2. AC loss performance of CS insert coil

    The ITER Central Solenoid (CS) model coil and the CS insert coil were fabricated, and the test was carried out. The AC loss measurement of the coil is one of the most important tests to determine coil performance. The AC loss of a short sample conductor for the CS insert coil was measured by using the calorimetric method, and the coupling time constants of the conductor were estimated to be 30 ms and 20 ms for pulse and discharge tests, respectively. The AC loss of the CS insert coil was measured by using the calorimetric method for pulse and discharge tests. The coupling time constant estimated from the result of the pulse tests was 34 ms and almost equal to that of the short sample. The coupling time constant for the discharge test was estimated to be 140 ms and about 4 times that of the pulse test. (author)

  3. Versatile roles of V-ATPases accessory subunit Ac45 in osteoclast formation and function.

    An Qin

    Full Text Available Vacuolar-type H(+-ATPases (V-ATPases are macromolecular proton pumps that acidify intracellular cargos and deliver protons across the plasma membrane of a variety of specialized cells, including bone-resorbing osteoclasts. Extracellular acidification is crucial for osteoclastic bone resorption, a process that initiates the dissolution of mineralized bone matrix. While the importance of V-ATPases in osteoclastic resorptive function is well-defined, whether V-ATPases facilitate additional aspects of osteoclast function and/or formation remains largely obscure. Here we report that the V-ATPase accessory subunit Ac45 participates in both osteoclast formation and function. Using a siRNA-based approach, we show that targeted suppression of Ac45 impairs intracellular acidification and endocytosis, both are prerequisite for osteoclastic bone resorptive function in vitro. Interestingly, we find that knockdown of Ac45 also attenuates osteoclastogenesis owing to a reduced fusion capacity of osteoclastic precursor cells. Finally, in an effort to gain more detailed insights into the functional role of Ac45 in osteoclasts, we attempted to generate osteoclast-specific Ac45 conditional knockout mice using a Cathepsin K-Cre-LoxP system. Surprisingly, however, insertion of the neomycin cassette in the Ac45-Flox(Neo mice resulted in marked disturbances in CNS development and ensuing embryonic lethality thus precluding functional assessment of Ac45 in osteoclasts and peripheral bone tissues. Based on these unexpected findings we propose that, in addition to its canonical function in V-ATPase-mediated acidification, Ac45 plays versatile roles during osteoclast formation and function.

  4. AcEST: DK953574 [AcEST

    Full Text Available tX Result : Swiss-Prot sp_hit_id P31549 Definition sp|P31549|THIP_ECOLI Thiamine transport system permeas...49|THIP_ECOLI Thiamine transport system permease protein ... 30 9.9 >sp|P31549|TH...IP_ECOLI Thiamine transport system permease protein thiP OS=Escherichia coli (strain K12) GN=thiP PE=3 SV=2 ...rt BLASTX 2.2.19 [Nov-02-2008] Reference: Altschul, Stephen F., Thomas L. Madden, Alejandro A. Schaffer... BAA-894) Align length 30 Score (bit) 33.9 E-value 7.8 Report BLASTX 2.2.19 [Nov-02-2008] Reference: Altschul, Stephen F., Thomas

  5. AcEST: DK950667 [AcEST

    Full Text Available QGLN 205 >sp|P24038|NIRT_PSEST Denitrification system component nirT OS=Pseudomonas stutzeri GN=nirT PE=2 SV...ification system component nirT OS=Ps... 29 8.6 >sp|Q5L6Z3|RUVA_CHLAB Holliday junc...icant alignments: (bits) Value sp|Q5L6Z3|RUVA_CHLAB Holliday junction ATP-dependent DNA helicas... 29 8.6 sp|P24038|NIRT_PSEST Denitr

  6. AC loss in superconducting tapes and cables

    Oomen, Marijn Pieter

    High-temperature superconductors are developed for use in power-transmission cables, transformers and motors. The alternating magnetic field in these devices causes AC loss, which is a critical factor in the design. The study focuses on multi-filament Bi-2223/Ag tapes exposed to a 50-Hz magnetic field at 77 K. The AC loss is measured with magnetic, electric and calorimetric methods. The results are compared to theoretical predictions based mainly on the Critical-State Model. The loss in high- temperature superconductors is affected by their characteristic properties: increased flux creep, high aspect ratio and inhomogeneties. Filament intergrowths and a low matrix resistivity cause a high coupling-current loss especially when the filaments are fully coupled. When the wide side of the tape is parallel to the external magnetic field, the filaments are decoupled by twisting. In a perpendicular field the filaments can be decoupled only by combining a short twist pitch with a transverse resistivity much higher than that of silver. The arrangement of the inner filaments determines the transverse resistivity. Ceramic barriers around the filaments cause partial decoupling in perpendicular magnetic fields at power frequencies. The resultant decrease in AC loss is greater than the accompanying decrease in critical current. With direct transport current in alternating magnetic field, the transport-current loss is well described with a new model for the dynamic resistance. The Critical- State Model describes well the magnetisation and total AC loss in parallel magnetic fields, at transport currents up to 0.7 times the critical current. When tapes are stacked face-to-face in a winding, the AC-loss density in perpendicular fields is greatly decreased due to the mutual shielding of the tapes. Coupling currents between the tapes in a cable cause an extra AC loss, which is reduced by a careful cable design. The total AC loss in complex devices with many tapes is generally well

  7. The Effective AC Response of Nonlinear Composites

    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.

  8. YBCO thin films in ac and dc films

    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)

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

    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.

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

    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. PMID:26672449

  11. AcEST: BP920400 [AcEST

    Full Text Available a' O... 29 8.3 sp|P57437|PTGCB_BUCAI PTS system glucose-specific EIICB componen... 29 8.3 sp|P38649|BGAT_MOUSE His...GGKNNIKNLDACITRLRITVSDISKVKQKDL 440 >sp|P38649|BGAT_MOUSE Histo-blood group ABO system transferase...iprot_sprot.fasta 412,525 sequences; 148,809,765 total letters Searching.......................................: uniprot_trembl.fasta 7,341,751 sequences; 2,391,615,440 total letter... protein OS=Schiz... 33 9.1 tr|A4QZA7|A4QZA7_MAGGR Predicted protein OS=Magnaporthe grisea G... 33 9.1 >tr|Q

  12. AcEST: DK958509 [AcEST

    Full Text Available 09|Adiantum capillus-veneris mRNA, clone: TST39A01NGRL0002_D04, 5' (700 letters) Database: uniprot_trembl.fasta...ype prothallia with plantlets Developmental stage gametophytes with sporophytes C...s-veneris mRNA, clone: TST39A01NGRL0002_D04, 5' (700 letters) Database: uniprot_sprot.fasta 412,525 sequences; 148,809,765 total let...ubsp. tul... 31 7.4 sp|Q8FZT8|KUP_BRUSU Probable potassium transport system prote...in ... 30 9.6 sp|B0CHH0|KUP_BRUSI Probable potassium transport system protein ... 30 9.6 sp|A5VRD1|KUP_BRUO2 Probable pota

  13. AcEST: DK952659 [AcEST

    Full Text Available ease protein... 31 4.5 sp|Q80V70|MEGF6_MOUSE Multiple epidermal growth factor-like doma...osphate transport system permease protein pstC OS=Mycobacterium leprae GN=pstC PE=3 SV=1 Length = 319 Score = 31.2 bits (69), Expe...e NUDT19, chlo... 34 0.69 sp|O88281|MEGF6_RAT Multiple epidermal growth factor-like domain... 32... 2.6 sp|O15014|ZN609_HUMAN Zinc finger protein 609 OS=Homo sapiens GN... 32 3.4 sp|Q50098|PSTC_MYCLE Phosphate transport system perm... 116 WVSLADCKVLLAS 128 >sp|O88281|MEGF6_RAT Multiple epidermal growth factor-like domains 6 OS=Rattus norveg

  14. AcEST: BP917675 [AcEST

    Full Text Available ptide transport system permease prot... 29 7.1 >sp|O96668...GFKGQPATHGQTKTHRR 239 >sp|P45053|OPPC_HAEIN Oligopeptide transport system permease protein oppC OS=Haemophil...e 56.9) Link to BlastX Result : Swiss-Prot sp_hit_id O96668 Definition sp|O96668|DTFA_DICDI Defective in tip forma...Score (bit) 30.0 E-value 4.2 Report BLASTX 2.2.19 [Nov-02-2008] Reference: Altschul, Stephen F., Thomas L. M...core (bit) 37.0 E-value 0.49 Report BLASTX 2.2.19 [Nov-02-2008] Reference: Altschul, Stephen F., Thomas L. M

  15. DC and AC transport properties on La0.8Sr0.2MnO3

    Zhantao Wei; Xinsheng Yang; Li Lv; Min Zhang; Yong Zhang

    2014-01-01

    Magnetoresistive sensor can be widely used in modern transportation field, such as the vehicle positioning and navigation system, vehicle detection system, and intelligent transportation system. In order to improve the efficiency of magnetoresistive sensor, we synthesized La0.8Sr0.2MnO3 polycrystalline bulks at different sintering temperatures and investigated their DC and AC transport properties in this work. As a result, all samples showed insulator-metal (I-M) phase transition, and the transition temperature (TI-M) shifted to higher temperature with the increase of sintering temperature. The TI-M measured at different AC frequencies was smaller than that measured at DC condition, which implied that the I-M phase transition was suppressed at AC frequencies. The resistivity mea-sured at high AC frequencies was larger than that measured at low AC frequencies, which could be attributed to the change of the magnetic penetration depth (d). However, the room-temperature AC-magnetoresistance (MR) at low frequencies was much larger than that at high frequencies and room-temperature DC-MR. These findings demon-strate that reducing the AC frequency is an effective way for enhancing the room-temperature MR, which can be used to promote the efficiency of magnetoresistive sensor.

  16. AcEST: DK950836 [AcEST

    Full Text Available poprotein releasing system, transmembra... 34 8.7 tr|A9L2Q3|A9L2Q3_SHEB9 Putative uncharacterized protein OS...r|B7F182|B7F182_ORYSJ cDNA clone:002-142-B09, full insert seque... 37 1.0 tr|A3R6T2|A3R6T2_PLAFA Erythrocyte membrane protein 1 (Fra... 5.1 tr|B1YT16|B1YT16_BURA4 Lipoprotein releasing system, transmembra... 34 6.6 tr|Q8KSY0|Q8KSY0_9ACTO Putative cytochrome... Lipoprotein releasing system, transmembra... 34 8.7 tr|B0IS17|B0IS17_RHILT OmpA/MotB domain protein OS=Rhiz...FQVRACGG*EQVSLWSSISKSLG 450 +L VRACGG E V W++ ++ G Sbjct: 130 RLYLAVRACGGFEAVRSWAAAAEMAG 155 >tr|A3R6T2|A3R6T2_PLAFA Erythrocyte memb

  17. Photovoltaic Simplified Boost Z Source Inverter for Ac Module Applications

    J. Sam Alaric

    2014-08-01

    Full Text Available This study mainly proposed PV z source boost inverter used to boundary grid or ac module applications. Separate types of converter used for solar system due to its current lagging, here capacitor multiplier based boost converter introduced for maintain the current lagging and voltage gain. Here, the switched inductor z source inverter implemented for grid interface. Proposed z source inverter is controlled by pulse width modulation. A simplified capacitor multiplier controlled by continuous conduction mode, A detailed topology analysis and a generalized discussion are given. The multiplier boost converter has the merits of maintain voltage level and reducing cost and current lagging. Simulation results are implemented and analysis MATLAB software.

  18. A PWM transistor inverter for an ac electric vehicle drive

    Slicker, J. M.

    1981-01-01

    A prototype system consisting of closely integrated motor, inverter, and transaxle has been built in order to demonstrate the feasibility of a three-phase ac transistorized inverter for electric vehicle applications. The microprocessor-controlled inverter employs monolithic power transistors to drive an oil-cooled, three-phase induction traction motor at a peak output power of 30 kW from a 144 V battery pack. Transistor safe switching requirements are discussed, and a circuit is presented for recovering trapped snubber inductor energy at transistor turn-off.

  19. Performance of Halbach magnetized brushless AC motors

    Zhu, Z.Q.; Xia, Z.P.; Shi, Y.F.; Howe, D.; Pride, A.; X. J. Chen

    2003-01-01

    The steady-state performance of Halbach magnetized brushless ac machines when operated in constant torque and flux-weakening modes is investigated both theoretically and experimentally, with particular emphasis on the influence of cross-coupling magnetic saturation on the torque capability.

  20. Ac-dc converter firing error detection

    Each of the twelve Booster Main Magnet Power Supply modules consist of two three-phase, full-wave rectifier bridges in series to provide a 560 VDC maximum output. The harmonic contents of the twelve-pulse ac-dc converter output are multiples of the 60 Hz ac power input, with a predominant 720 Hz signal greater than 14 dB in magnitude above the closest harmonic components at maximum output. The 720 Hz harmonic is typically greater than 20 dB below the 500 VDC output signal under normal operation. Extracting specific harmonics from the rectifier output signal of a 6, 12, or 24 pulse ac-dc converter allows the detection of SCR firing angle errors or complete misfires. A bandpass filter provides the input signal to a frequency-to-voltage converter. Comparing the output of the frequency-to-voltage converter to a reference voltage level provides an indication of the magnitude of the harmonics in the ac-dc converter output signal

  1. AC loss in superconducting tapes and cables

    Oomen, Marijn Pieter

    2000-01-01

    The present study discusses the AC loss in high-temperature superconductors. Superconducting materials with a relatively high critical temperature were discovered in 1986. They are presently developed for use in large-scale power-engineering devices such as power-transmission cables, transformers an

  2. AcEST: BP911777 [AcEST

    Full Text Available tr|B6YYG2|B6YYG2_9RHOB Binding-protein-dependent transport systems inner membrane component, putative OS=Pseudovibr...terized protein OS=Branchiostoma floridae GN=BRAFLDRAFT_111045 PE=4 SV=1 Length = 4...AST and PSI-BLAST: a new generation of protein database search programs, Nucleic Acids Res. 25:3389-3402. Qu... J. Lipman (1997), Gapped BLAST and PSI-BLAST: a new generation of protein database search programs, Nucleic Acid...nts: (bits) Value tr|A7GQV4|A7GQV4_BACCN Putative uncharacterized protein OS=Baci

  3. AcEST: BP916028 [AcEST

    Full Text Available EGHFAREC 934 >tr|A1TQ72|A1TQ72_ACIAC Binding-protein-dependent transport systems inner membra...terized protein OS=Branchiostoma floridae GN=BRAFLDRAFT_124711 PE=4 SV=1 Length = 39...tion of protein database search programs, Nucleic Acids Res. 25:3389-3402. Query= BP9160... J. Lipman (1997), Gapped BLAST and PSI-BLAST: a new generation of protein database search programs, Nucleic Acid...ne component OS=Acidovorax avenae subsp. citrulli (strain AAC00-1) GN=Aave_2537 PE=3 SV=1 Length

  4. AcEST: BP920336 [AcEST

    Full Text Available Putative uncharacterized protein OS=Bifidobacterium adolescentis L2-32 GN=BIFADO_00752 PE=4 SV=1 Length = 311 Score = 32.7 bits...ute binding protein of ABC transporter system OS=Bifidobacterium adolescentis (strain ATCC 15703 / DSM 200...ne Score E Sequences producing significant alignments: (bits) Value sp|Q0VGE8|Z816A_HUMAN...ne Score E Sequences producing significant alignments: (bits....0 E-value 1.2 Report BLASTX 2.2.19 [Nov-02-2008] Reference: Altschul, Stephen F., Thomas L. Madden, Alejand

  5. AcEST: DK960823 [AcEST

    Full Text Available TST39A01NGRL0008_H04 647 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0008_H04. 5' end seq ... p|A6TFA8|NIKR_KLEP7 Nickel-responsive regulator OS=Klebsiella ... pneumoniae subsp. pneumoniae (strain ATCC 700721 / ... p|A6TFA8|NIKR_KLEP7 Nickel-responsive regulator OS=Klebsiella ... p... 30 7.5 sp|Q5UY89|UVRC_HALMA UvrABC system pro ...

  6. AcEST: DK953949 [AcEST

    Full Text Available TST39A01NGRL0019_C05 483 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0019_C05. 5' end seq ... |P10488|ALBR_KLEOX Albicidin resistance protein OS=Klebsiella ... oxytoca Align length 31 Score (bit) 30.0 E-value 5 ... |P10488|ALBR_KLEOX Albicidin resistance protein OS=Klebsiella ... ... 30 5.0 sp|Q9Z985|UVRA_CHLPN UvrABC system prot ...

  7. AcEST: DK954442 [AcEST

    Full Text Available ...........................done Score E Sequences producing significant alignments: (bits) Value sp|Q3KH21|KUP_PSEPF Probable pota...42|Adiantum capillus-veneris mRNA, clone: TST39A01NGRL0020_H05, 5' (602 letters) Database: uniprot_trembl.fasta...ype prothallia with plantlets Developmental stage gametophytes with sporophytes C...tX Result : Swiss-Prot sp_hit_id Q3KH21 Definition sp|Q3KH21|KUP_PSEPF Probable potassium transport system p...442|Adiantum capillus-veneris mRNA, clone: TST39A01NGRL0020_H05, 5' (602 letters) Datab

  8. AcEST: BP921167 [AcEST

    Full Text Available .09 Report BLASTX 2.2.19 [Nov-02-2008] Reference: Altschul, Stephen F., Thomas L. Madden, Alejandro A. Schaffer...tion initiation factor IF-2 OS=Thermu... 30 4.9 sp|P01096|ATIF1_BOVIN ATPase inhibitor, mitochondrial OS=Bos...ence: Altschul, Stephen F., Thomas L. Madden, Alejandro A. Schaffer, Jinghui Zhang, Zheng Zhang, Webb Miller...o-component system sensor kinase/response regulator, bifunctional protein OS=Streptomyces avermitilis GN=SAV...VERME-DERIKTEVTQALAKGETKRAREIEIEAREAKRL 268 >tr|Q55QG3|Q55QG3_CRYNE Putative uncharacterized protein OS=Cryptococcus neoforma

  9. AcEST: DK955339 [AcEST

    Full Text Available Q9R1J8 Definition sp|Q9R1J8|P3H1_RAT Prolyl 3-hydroxylase 1 OS=Rattus norvegicus Align length 39 Score (bit) 33.5 E-value 0.76 Repor...se NCED3, c... 32 2.2 sp|Q89A36|PTM3C_BUCBP PTS system mannitol-specific EIICBA compon... 32 2.9 sp|Q0BGI1|PPK_BURCM Polyphosphate...383 PLSVSPRKRDSNSR 424 + V P+ ++SN++ Sbjct: 71 AIVVKPKAKESNTK 84 >sp|Q89A36|PTM3C_BUCBP PTS system mannitol-specific EIICBA compo...in OS=Phaeosphaeria nodorum Align length 80 Score (bit) 35.4 E-value 2.2 Report BLASTX 2.2.19 [Nov-02-2008] Refere...in OS=Ixode... 33 8.5 tr|A7SXL9|A7SXL9_NEMVE Predicted protein OS=Nematostella vectens... 33

  10. A Comparison Between Two Average Modelling Techniques of AC-AC Power Converters

    Pawel Szczesniak

    2015-03-01

    Full Text Available In this paper, a comparative evaluation of two modelling tools for switching AC-AC power converters is presented. Both of them are based on average modelling techniques. The first approach is based on the circuit averaging technique and consists in the topological manipulations, applied to a converters states. The second approach makes use of state-space averaged model of the converter and is based on analytical manipulations using the different state representations of a converter. The two modelling techniques are applied to a same AC-AC converter called matrix-reactance frequency converter based on buck-boost topology. These techniques are compared on the basis of their rapidity, quantity of calculations and transformations and its limitations.

  11. SOLAR TO AC POWER SOURCE FOR REMOTE AREAS USING SEIG

    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.

  12. Generalized Steady-State VSC MTDC Model for Sequential AC/DC Power Flow Algorithms

    Beerten, Jef; Cole, Stijn; Belmans, Ronnie

    2012-01-01

    In this paper, a steady-state multi-terminal voltage source converter high voltage direct current (VSC MTDC) model is introduced. The proposed approach is extended to include multiple AC and DC grids with arbitrary topologies. The DC grids can thereby interconnect arbitrary buses in one or more non-synchronized AC systems. The converter equations are derived in their most general format and correctly define all set-points with respect to the system bus instead of the converter or filter bus, ...

  13. AcEST: BP918973 [AcEST

    Full Text Available nsport systems inner membrane component OS=Paenibacillus s...s inner membrane component OS=Paenibacillus sp. JDR-2 GN=Pjdr...thine ami... 33 9.4 tr|B8G3C6|B8G3C6_9CHLR Inner-membrane translocator OS=Chloroflex... 33 9.4 tr|B8BQF2|B8BQF2_THAPS Tra...16|B6M816_BRAFL Putative uncharacterized protein (Fragment) OS=Branchiostoma floridae GN=BRAFLDRAFT_220336 P...M++E C I R KW QW IVP Sbjct: 203 DYLQSLRRLCDQQDWLLMLDEVQCGIGRTGKWFAHQWAGIVP 244 >tr|B8G3C6|B8G3C6_9CHLR Inner-membrane tra

  14. AcEST: DK963493 [AcEST

    Full Text Available tal transport system membrane pr... 30 6.0 sp|B0S032|Y209_FINM2...IGDPYRWLEDPDAEEVKEFVQSQVKLTDSVL 87 >tr|B6MUZ8|B6MUZ8_BRAFL Putative uncharacterized protein OS=Branchiostoma floridae... >tr|B6LF02|B6LF02_BRAFL Putative uncharacterized protein OS=Branchiostoma floridae GN=BRAFLDRAFT_204923 PE=...DTYFGNQVSDPYRWLEDDRAEDTKAWVQQE 67 >sp|Q89A78|RL5_BUCBP 50S ribosomal protein L5 OS=Buchnera aphidicola subsp. Baizongia pistaciae...s m... 49 1e-04 tr|Q543B9|Q543B9_MOUSE Putative uncharacterized protein OS=Mus m... 49 1e-04 tr|Q7UIT3|Q7UIT

  15. AcEST: BP914688 [AcEST

    Full Text Available REQRD 235 >tr|A1A3E7|A1A3E7_BIFAA Probable solute binding protein of ABC transporter system OS=Bifidobacterium adolescent...ne Score E Sequences producing significant alignments: (bits) Value tr|A7R110|A7R110_VITVI Chromosome chr4 sc...s Searching..................................................done Score E Sequences producing significant alignments: (bits...t : TrEMBL tr_hit_id A7R110 Definition tr|A7R110|A7R110_VITVI Chromosome chr4 scaffold_333, whole genome shotgun sequence (Fragment...ase II... 33 9.3 >tr|A7R110|A7R110_VITVI Chromosome chr4 scaffold_333, whole genome shotgun sequence (Fragment

  16. AcEST: BP911614 [AcEST

    Full Text Available -05 tr|Q0G0K8|Q0G0K8_9RHIZ UvrABC system protein B OS=Fulvimarina pe... 42 0.016 tr|A6W3B5|A6W3B5_MARMS RNA polymerase, sigma...ltschul, Stephen F., Thomas L. Madden, Alejandro A. Schaffer, Jinghui Zhang, Zheng Zhang, Webb Miller, and David J. Lipman...s L. Madden, Alejandro A. Schaffer, Jinghui Zhang, Zheng Zhang, Webb Miller, and David J. Lipman..._XENLA Sestrin-1 OS=Xenopus laevis GN=sesn1 PE=2 ... 26 9.6 sp|P0C0J8|P46_MYCHJ 46 kDa surface antigen OS=Mycoplasma...SGLQARMERLKSGSM 1963 >tr|Q8S912|Q8S912_TOBAC Microtubule bundling polypeptide TMBP200 OS=Nicotiana

  17. AcEST: DK945366 [AcEST

    Full Text Available YMU02A01NGRL0009_B05 347 Adiantum capillus-veneris mRNA. clone: YMU02A01NGRL0009_B05. 5' end seq ... t sp_hit_id Q6FA90 Definition sp|Q6FA90|DCTA_ACIAD C4 -dicarboxylate transport protein OS=Acinetobacter s ... cant alignments: (bits) Value sp|Q6FA90|DCTA_ACIAD C4 -dicarboxylate transport protein OS=Acine... 32 1.3 ... system ATP-binding... 30 2.8 sp|A8G823|DCTA_SERP5 C4 -dicarboxylate transport protein OS=Serra... 30 2.8 ... sp|Q3YVR0|DCTA_SHISS C4 -dicarboxylate transport protein OS=Shige... 30 3.7 ...

  18. AcEST: BP913583 [AcEST

    Full Text Available 30 7.6 sp|Q14692|BMS1_HUMAN Ribosome biogenesis protein BMS1 homolog OS... 30 7.6 sp|Q8WTW3|COG1_HUMAN Conserved oligomer...MBL (release 39.9) Link to BlastX Result : TrEMBL tr_hit_id A0MV34 Definition tr|A0MV34|A0MV34_ACRMI Ventral nerv........................done Score E Sequences producing significant alignments: (bits) Value tr|A0MV34|A0MV34_ACRMI Ventral nerv...tase like protein OS=Tet... 33 9.7 >tr|A0MV34|A0MV34_ACRMI Ventral nervous system defective...h programs, Nucleic Acids Res. 25:3389-3402. Query= BP913583|Adiantum capillus-veneris mRNA, clone: YMU001_000031_H03. (542 letter

  19. AcEST: BP919437 [AcEST

    Full Text Available B96_SALTO Peptidase S9, prolyl oligopeptidase activ... 33 7.1 tr|Q2SPP8|Q2SPP8_HAHCH Predicted phosphohydrol...4 GRSRIYTLPFEGGVPRLITPLGPSYLHGWSPDGKQLAYCAERNGNFDVYV 163 >tr|A4XB96|A4XB96_SALTO Peptidase S9, prolyl oligop...in OS=Des... 35 2.4 tr|A6LG82|A6LG82_PARD8 Periplasmic component of the Tol biopolym... 33 7.1 tr|A4XB96|A4X...6LG82_PARD8 Periplasmic component of the Tol biopolymer transport system OS=Parabacteroides distasonis (stra...|B7DGU5|B7DGU5_DESSA Sua5/YciO/YrdC/YwlC family protein OS=Desulfovibrio salexigens DSM 2638 Alig

  20. AcEST: DK950560 [AcEST

    Full Text Available A0|UVRC_SYNWW UvrABC system protein C OS=Syntrophomonas w... 36 0.28 sp|Q9NX45|SOLH2_HUMAN Spermatogenesis- and oogenesis-spe...y: 180 EKKMLDFFYDHFY 218 E + ++FF H+Y Sbjct: 291 ENEAMEFFIKHYY 303 >sp|Q9NX45|SOLH2_HUMAN Sperma...ore (bit) 36.2 E-value 0.22 Report BLASTX 2.2.19 [Nov-02-2008] Reference: Altschul, Stephen F., Thomas L. Ma... 2.2.19 [Nov-02-2008] Reference: Altschul, Stephen F., Thomas L. Madden, Alejandro A. Schaffer...5K7K9_PLAVI Putative uncharacterized protein OS=Plasm... 39 0.41 tr|B1IDS3|B1IDS3_CLOBK Metallo-beta-lactamas

  1. AcEST: DK960773 [AcEST

    Full Text Available 83 Definition sp|O43683|BUB1_HUMAN Mitotic checkpoint serine/threonine-protein ki...oducing significant alignments: (bits) Value sp|O43683|BUB1_HUMAN Mitotic checkpo...int serine/threonine-protein... 40 6e-05 sp|O08901|BUB1_MOUSE Mitotic checkpoint serine/threonine-protein......OS=Sch... 32 0.97 sp|Q65TB7|LOLD_MANSM Lipoprotein-releasing system ATP-binding pr... 31 1.7 sp|Q0BN75|LOLD_FRATO Lipop...=Vanderwal... 30 3.7 sp|O59767|MAD3_SCHPO Mitotic spindle checkpoint component mad3 O... 30 3.7 sp|Q02357|AN

  2. AcEST: BP918269 [AcEST

    Full Text Available |Q92SH0|Q92SH0_RHIME Probable multidrug-efflux system transmem... 35 3.2 tr|A0YJJ8|A0YJJ8_9CYAN Putative uncharacterized...C628_VITVI Putative uncharacterized protein OS=Vitis... 49 1e-04 tr|Q6YNS0|Q6YNS0_PRUAV Putative translation-initia...|Q6Z720|Q6Z720_ORYSJ Putative Eukaryotic translation initiatio... 33 7.0 tr|Q0E4E1|Q0E4E1_ORYSJ Os...|Q6YNS0|Q6YNS0_PRUAV Putative translation-initiation factor 3 subunit OS=Prunus avium PE=2 ...porter, hydrophobe/amphiphile efflux-1 (HAE1) family OS=Sinorhizobium medicae (stra

  3. Engineering Design of the ITER AC/DC Power Supplies

    To design high power pulse power supplies, especially in huge power supplies have not designed till now, it is necessary to analyze a system's characteristics and relations with another systems as well as to know high voltage, high current control technologies. Contents of this project are; - Study for the engineering designs changed recently by ITER Organization(IO) and writing specifications for the power supplies to reduce project risk. - Detailed analysis of the AC/DC Converters and writing subtask reports on the Task Agreement. - Study for thyristor numbers, DCR's specifications for Korea-China sharing meetings. - Study for the grounding systems of the ITER power supply system. The results may used as one of reference for practical designs of the high power coil power supplies and also may used in various field such as electroplating, plasma arc furnaces, electric furnaces

  4. Design of Three Phase Matrix Converter AC-AC Utility Power Supply using SPWM Technique

    Sagar.S.Pawar; Prakash.T.Patil

    2015-01-01

    This paper describes the control analysis and design of an three phase matrix AC-AC utility power supply .The SPWM modulation techniques is used to control the desired output voltage and gives the control output voltage and reduced input harmonic distortions .In this Matrix converter Input is directly connected to output no DC link components is required. Simulation had been done using mat lab simulink and Simulated results are observed

  5. Design of Three Phase Matrix Converter AC-AC Utility Power Supply using SPWM Technique

    Sagar. S. Pawar

    2015-04-01

    Full Text Available This paper describes the control analysis and design of an three phase matrix AC-AC utility power supply .The SPWM modulation techniques is used to control the desired output voltage and gives the control output voltage and reduced input harmonic distortions .In this Matrix converter Input is directly connected to output no DC link components is required. Simulation had been done using mat lab simulink and Simulated results are observed

  6. A Comparison Between Two Average Modelling Techniques of AC-AC Power Converters

    Pawel Szczesniak

    2015-01-01

    In this paper, a comparative evaluation of two modelling tools for switching AC-AC power converters is presented. Both of them are based on average modelling techniques. The first approach is based on the circuit averaging technique and consists in the topological manipulations, applied to a converters states. The second approach makes use of state-space averaged model of the converter and is based on analytical manipulations using the different state representations of a converter. The two m...

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

    Ljusev, P.; Andersen, Michael A.E.

    2005-07-01

    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 will provide better efficiency and higher level of integration, leading to lower component count, volume and cost, but at the expense of a minor performance deterioration. (au)

  8. Implementation of Low Frequency Ac to High Frequency Ac with Single Stage Zvs-Pwm Inverter

    S. Arumugam S. Ramareddy M. Sridhar

    2011-01-01

    This paper presents a novel soft-switching pulse width modulation (PWM) utility frequency AC to high frequency (HF) AC power conversion circuit incorporating boost-active clamp single stage inverter topology. This power converter is more suitable and acceptable for cost effective HF consumer induction heating applications. Its operating principle is presented. The operating performances of this high frequency inverter using the latest insulated gate bipolar transistors are illustrated, which ...

  9. A new class of hybrid AC/AC direct power converters

    Klumpner, Christian; Wijekoon, Thiwanka; Wheeler, Patrick

    2005-01-01

    Variable voltage and variable frequency conversion of electrical energy from an AC source to an AC load is done in traditional power converters via a DC-link where an energy storage element (electrolytic capacitors) is situated. Despite its well-known benefits, it has the disadvantage of being bulky and to limit the converter lifetime. On the other hand, Direct Power Conversion (DPC) is an attractive concept, which doesn’t need an energy storage buffer, but has two main disadvantages: reduced...

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

    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...... will provide better efficiency and higher level of integration, leading to lower component count, volume and cost, but at the expense of a minor performance deterioration....

  11. Interior point algorithm-based power flow optimisation of a combined AC and DC multi-terminal grid

    Farhan Beg

    2015-01-01

    Full Text Available The high cost of power electronic equipment, lower reliability and poor power handling capacity of the semiconductor devices had stalled the deployment of systems based on DC (multi-terminal direct current system (MTDC networks. The introduction of voltage source converters (VSCs for transmission has renewed the interest in the development of large interconnected grids based on both alternate current (AC and DC transmission networks. Such a grid platform also realises the added advantage of integrating the renewable energy sources into the grid. Thus a grid based on DC MTDC network is a possible solution to improve energy security and check the increasing supply demand gap. An optimal power solution for combined AC and DC grids obtained by the solution of the interior point algorithm is proposed in this study. Multi-terminal HVDC grids lie at the heart of various suggested transmission capacity increases. A significant difference is observed when MTDC grids are solved for power flows in place of conventional AC grids. This study deals with the power flow problem of a combined MTDC and an AC grid. The AC side is modelled with the full power flow equations and the VSCs are modelled using a connecting line, two generators and an AC node. The VSC and the DC losses are also considered. The optimisation focuses on several different goals. Three different scenarios are presented in an arbitrary grid network with ten AC nodes and five converter stations.

  12. AC losses in a HTS coil carrying DC current in AC external magnetic field

    We electrically measured AC losses in a Bi2223/Ag-sheathed pancake coil excited by a DC current in AC external magnetic field. Losses in the coil contain two kinds of loss components that are the magnetization losses and dynamic resistance losses. In the measurement, current leads to supply a current to the coil were specially arranged to suppress electromagnetic coupling between the coil current and the AC external magnetic field. A double pick-up coils method was used to suppress a large inductive voltage component contained in voltage signal for measuring the magnetization losses. It was observed that the magnetization losses were dependent on the coil current and that a peak of a curve of the loss factor vs. amplitude of the AC external magnetic field shifted to lower amplitude of the AC magnetic field as the coil current increased. This result suggests the full penetration magnetic field of the coil tape decreases as the coil current increases. The dynamic resistance losses were measured by measuring a DC voltage appearing between the coil terminals. It was observed that the DC voltage appearing in the coil subject to the AC external magnetic field was much larger than that in the coil subject to DC magnetic field

  13. Electroporation of cells using EM induction of ac fields by a magnetic stimulator

    This paper describes a method of effectively electroporating mammalian cell membranes with pulsed alternating-current (ac) electric fields at field strengths of 30-160 kV m-1. Although many in vivo electroporation protocols entail applying square wave or monotonically decreasing pulses via needles or electrode plates, relatively few have explored the use of pulsed ac fields. Following our previous study, which established the effectiveness of ac fields for electroporating cell membranes, a primary/secondary coil system was constructed to produce sufficiently strong electric fields by electromagnetic induction. The primary coil was formed from the applicator of an established transcranial magnetic stimulation (TMS) system, while the secondary coil was a purpose-built device of a design which could eventually be implanted into tissue. The effects of field strength, pulse interval and cumulative exposure time were investigated using microscopy and flow cytometry. Results from experiments on concentrated cell suspensions showed an optimized electroporation efficiency of around 50%, demonstrating that electroporation can be practicably achieved by inducing such pulsed ac fields. This finding confirms the possibility of a wide range of in vivo applications based on magnetically coupled ac electroporation.

  14. ac driving amplitude dependent systematic error in scanning Kelvin probe microscope measurements: Detection and correction

    The dependence of the contact potential difference (CPD) reading on the ac driving amplitude in scanning Kelvin probe microscope (SKPM) hinders researchers from quantifying true material properties. We show theoretically and demonstrate experimentally that an ac driving amplitude dependence in the SKPM measurement can come from a systematic error, and it is common for all tip sample systems as long as there is a nonzero tracking error in the feedback control loop of the instrument. We further propose a methodology to detect and to correct the ac driving amplitude dependent systematic error in SKPM measurements. The true contact potential difference can be found by applying a linear regression to the measured CPD versus one over ac driving amplitude data. Two scenarios are studied: (a) when the surface being scanned by SKPM is not semiconducting and there is an ac driving amplitude dependent systematic error; (b) when a semiconductor surface is probed and asymmetric band bending occurs when the systematic error is present. Experiments are conducted using a commercial SKPM and CPD measurement results of two systems: platinum-iridium/gap/gold and platinum-iridium/gap/thermal oxide/silicon are discussed

  15. 21 CFR 880.5500 - AC-powered patient lift.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or...

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

    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.

  17. Propiedades acústicas de los paneles de carrizo

    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.

  18. Dicty_cDB: FCL-AC08 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC08 (Link to dictyBase) - - - Contig-U15080-1 FCL-AC08P ...(Link to Original site) FCL-AC08F 616 FCL-AC08Z 291 FCL-AC08P 907 - - Show FCL-AC08 Library FCL (Link to library) Clone ID FCL-...-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC08Q....Seq.d/ Representative seq. ID FCL-AC08P (Link to Original site) Representative DNA sequence >FCL-AC08 (FCL-AC08Q) /CSM/FCL/FCL-...ignificant alignments: (bits) Value FCL-AC08 (FCL-AC08Q) /CSM/FCL/FCL-AC/FCL-AC08Q.Seq.d/ 1322 0.0 SFA226 (S

  19. Dissipation and AC loss in high Tc superconductors destined for power applications

    Full text: Superconductivity, which was discovered at the beginning of this century, has long been promoted as a solution to many power engineering problems. This was because a superconductor exhibits zero resistance to DC currents and a very low resistance to AC currents. Historically however, power utility applications, whilst technically feasible, were not economically viable. With the discovery of high temperature superconductors in the late 80's there has been a resurgence of interest in the use of superconductivity for power applications: cables, motors, generators, transformers, fault current limiters. In order for power applications of superconductors to be realized, in addition to a high current density, low AC losses and transient stability are also necessary. Whilst much work worldwide has been devoted to increasing critical current densities of high Tc materials, reliable AC loss characterisation of power applications and low loss conductor designs optimized for each application still remain to be developed. Here, calorimetric methods for the measurement of AC losses for high Tc wires will be compared to electric and magnetization methods. The relative merits of each method will be discussed. One of the key differences between high and low Tc superconductors is in the nature of E-J curves. In high Tc materials these curves are extended, i.e. E increases gradually with J. This has consequences for both AC losses and stability. In this article the nature of AC losses and stability in high temperature superconducting wires will be discussed: hysteretic losses, eddy current losses, role of flux creep, anisotropy, dimensional effects ..., and compared to those for low temperature wires such as multifilamentary NbTi and NbSn. In conclusion, the key requirements will be discussed that must be achieved in order that superconducting technologies gain acceptance in power engineering applications: current density, AC losses, transient response, mechanical

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

    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.

  1. Fractional ac Josephson effect in unconventional superconductors

    For certain orientations of Josephson junctions between two px-wave or two d-wave superconductors, the subgap Andreev bound states produce a 4π-periodic relation between the Josephson current I and the phase difference ψ: I propor to sin(ψ/2) . Consequently, the ac Josephson current has the fractional frequency eV/h where V is the dc voltage. In the tunneling limit, the Josephson current is proportional to the first power (not square) of the electron tunneling amplitude. Thus, the Josephson current between unconventional superconductors is carried by single electrons, rather than by Cooper pairs. The fractional ac Josephson effect can be observed experimentally by measuring frequency spectrum of microwave radiation from the junction

  2. β-delayed fission from 230Ac

    ThO2 is irradiated with 60 MeV/u 18O beams. 230Ra is produced via the multi-nucleon transfer and dissipative fragmentation reactions of the target. 230Ra is radio-chemical separated from ThO2 and the other reaction products. The thin Ra sources are prepared. The mica fission track detectors are exposed to the Ra sources. γ-rays of Ra decay in the sources are measured by a HPGe detector. The mica foil is etched in HF solution. The etched mica foil is scanned with an optical microscope. The fission tracks that should come from β-delayed fission of 230Ac are observed. The β-delayed fission probability of 230Ac is determined to be (1.19 +- 0.85) x 10-8

  3. AC Dielectrophoresis Using Elliptic Electrode Geometry

    S. M. Rezaul Hasan; Aanan Khurma

    2011-01-01

    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...

  4. Lazy AC-Pattern Matching for Rewriting

    Belkhir, Walid; 10.4204/EPTCS.82.3

    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.

  5. Entropy production in ac-calorimetry

    Garden, Jean-Luc; Richard, Jacques

    2007-01-01

    In calorimetry and particularly in heat capacity measurements, different characteristic relaxation time constants may perturb the experiment which cannot be considered at thermodynamic equilibrium. In this case, thermodynamics of irreversible processes has to be taken into account and the calorimetric measurements must be considered as dynamic. In a temperature modulated experiment, such as ac-calorimetry, these non-equilibrium experiments give rise to the notion of frequency dependent comple...

  6. Analysis and Implementation of Real Number Extended Sliding Surface with Integral Compensation for DC-AC Converters

    This paper proposes a real number extended sliding surface (RNESS) with integral compensation (IC) for the application of DC-AC converters. Classic sliding surface (CSS) is insensitive to system uncertainties, but in sliding action its system dynamics becomes a reduced-order dimension and thus lost the partial system dynamics. For recovering incomplete system response, the RNESS is designed and can retrieve incomplete system response of the CSS. However, steady-state errors still exist in system dynamics of the RNESS and cause high converter voltage harmonics. To overcome steady-state errors, a modified RNESS by the addition of IC is proposed. With the proposed method, the system yields a DC-AC converter with high-quality AC output voltage. Experiments are performed in support of the proposed method

  7. Comparative Study of DC and AC Microgrids in Commercial Buildings Across Different Climates and Operating Profiles: Preprint

    Fregosi, D.; Ravula, S.; Brhlik, D.; Saussele, J.; Frank, S.; Bonnema, E.; Scheib, J.; Wilson, E.

    2015-04-22

    Bosch has developed and demonstrated a novel DC microgrid system designed to maximize utilization efficiency for locally generated photovoltaic energy while offering high reliability, safety, redundancy, and reduced cost compared to equivalent AC systems. Several demonstration projects validating the system feasibility and expected efficiency gains have been completed and additional ones are in progress. This work gives an overview of the Bosch DC microgrid system and presents key results from a large simulation study done to estimate the energy savings of the Bosch DC microgrid over conventional AC systems. The study examined the system performance in locations across the United States for several commercial building types and operating profiles and found that the Bosch DC microgrid uses generated PV energy 6%–8% more efficiently than traditional AC systems.

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

    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.

  9. Progress on advanced dc and ac induction drives for electric vehicles

    Schwartz, H. J.

    1982-01-01

    Progress is reported in the development of complete electric vehicle propulsion systems, and the results of tests on the Road Load Simulator of two such systems representative of advanced dc and ac drive technology are presented. One is the system used in the DOE's ETV-1 integrated test vehicle which consists of a shunt wound dc traction motor under microprocessor control using a transistorized controller. The motor drives the vehicle through a fixed ratio transmission. The second system uses an ac induction motor controlled by transistorized pulse width modulated inverter which drives through a two speed automatically shifted transmission. The inverter and transmission both operate under the control of a microprocessor. The characteristics of these systems are also compared with the propulsion system technology available in vehicles being manufactured at the inception of the DOE program and with an advanced, highly integrated propulsion system upon which technology development was recently initiated.

  10. Alternative splicing of the maize Ac transposase transcript in transgenic sugar beet (Beta vulgaris L.).

    Lisson, Ralph; Hellert, Jan; Ringleb, Malte; Machens, Fabian; Kraus, Josef; Hehl, Reinhard

    2010-09-01

    The maize Activator/Dissociation (Ac/Ds) transposable element system was introduced into sugar beet. The autonomous Ac and non-autonomous Ds element excise from the T-DNA vector and integrate at novel positions in the sugar beet genome. Ac and Ds excisions generate footprints in the donor T-DNA that support the hairpin model for transposon excision. Two complete integration events into genomic sugar beet DNA were obtained by IPCR. Integration of Ac leads to an eight bp duplication, while integration of Ds in a homologue of a sugar beet flowering locus gene did not induce a duplication. The molecular structure of the target site indicates Ds integration into a double strand break. Analyses of transposase transcription using RT-PCR revealed low amounts of alternatively spliced mRNAs. The fourth intron of the transposase was found to be partially misspliced. Four different splice products were identified. In addition, the second and third exon were found to harbour two and three novel introns, respectively. These utilize each the same splice donor but several alternative splice acceptor sites. Using the SplicePredictor online tool, one of the two introns within exon two is predicted to be efficiently spliced in maize. Most interestingly, splicing of this intron together with the four major introns of Ac would generate a transposase that lacks the DNA binding domain and two of its three nuclear localization signals, but still harbours the dimerization domain. PMID:20512402

  11. Distribution of AC loss in a HTS magnet for SMES with different operating conditions

    Xu, Y., E-mail: xuyinghust@163.com [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, R and D Center of Applied Superconductivity, Huazhong University of Science and Technology, Wuhan 430074 (China); Tang, Y.; Ren, L.; Jiao, F. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, R and D Center of Applied Superconductivity, Huazhong University of Science and Technology, Wuhan 430074 (China); Song, M.; Cao, K.; Wang, D. [Yunnan Electric Power Research Institute, Kunming City 650217 (China); Wang, L.; Dong, H. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, R and D Center of Applied Superconductivity, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2013-11-15

    Highlights: •We present a model to calculate the distribution of AC loss for a storage magnet. •Comparative analysis of AC loss with different operating conditions has done. •The nonuniform distribution factor “d” is proposed to estimate the inhomogeneity of a storage magnet. •The model predicts the loss distribution and crucial areas which are suffering from the high AC loss. This is significant for the conduction-cooled structure design. -- Abstract: The AC loss induced in superconducting tape may affect the performance of a superconducting device applied to power system, such as transformer, cable, motor and even Superconducting Magnetic Energy Storage (SMES). The operating condition of SMES is changeable due to the need of compensation to the active or reactive power according to the demand of a power grid. In this paper, it is investigated that the distribution of AC loss for a storage magnet on different operating conditions, which is based on finite element method (FEM) and measured properties of BSCCO/Ag tapes. This analytical method can be used to optimize the SMES magnet.

  12. Distributed Control for Autonomous Operation of a Three-Port AC/DC/DS Hybrid Microgrid

    Wang, Peng; Jin, Chi; Zhu, Dexuan;

    2015-01-01

    module can operate independently without communication links. This would benefit for riding through communication malfunction in multilayer supervision control system; 2) a multilevel power exchange control for scheduling LPS, GPS, and SPS has been developed to reduce unnecessary power exchange between......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...

  13. Distribution of AC loss in a HTS magnet for SMES with different operating conditions

    Xu, Y.; Tang, Y.; Ren, L.; Jiao, F.; Song, M.; Cao, K.; Wang, D.; Wang, L.; Dong, H.

    2013-11-01

    The AC loss induced in superconducting tape may affect the performance of a superconducting device applied to power system, such as transformer, cable, motor and even Superconducting Magnetic Energy Storage (SMES). The operating condition of SMES is changeable due to the need of compensation to the active or reactive power according to the demand of a power grid. In this paper, it is investigated that the distribution of AC loss for a storage magnet on different operating conditions, which is based on finite element method (FEM) and measured properties of BSCCO/Ag tapes. This analytical method can be used to optimize the SMES magnet.

  14. Exponential Lower Bounds for AC0-Frege Imply Superpolynomial Frege Lower Bounds

    Filmus, Yuval; Pitassi, Toniann; Santhanam, Rahul

    2011-01-01

    We give a general transformation which turns polynomial-size Frege proofs to subexponential-size AC0-Frege proofs. This indicates that proving exponential lower bounds for AC0-Frege is hard, since it is a longstanding open problem to prove super-polynomial lower bounds for Frege. Our construction is optimal for tree-like proofs. As a consequence of our main result, we are able to shed some light on the question of weak automatizability for bounded-depth Frege systems. First, we present a simp...

  15. Magnetic images of the disintegration process of tablets in the human stomach by ac biosusceptometry

    Corá, L. A.; Andreis, U.; Romeiro, F. G.; Américo, M. F.; Oliveira, R. B.; Baffa, O.; Miranda, J. R. A.

    2005-12-01

    Oral administration of solid dosage forms is usually preferred in drug therapy. Conventional imaging methods are essential tools to investigate the in vivo performance of these formulations. The non-invasive technique of ac biosusceptometry has been introduced as an alternative in studies focusing on gastrointestinal motility and, more recently, to evaluate the behaviour of magnetic tablets in vivo. The aim of this work was to employ a multisensor ac biosusceptometer system to obtain magnetic images of disintegration of tablets in vitro and in the human stomach. The results showed that the transition between the magnetic marker and the magnetic tracer characterized the onset of disintegration (t50) and occurred in a short time interval (1.1 ± 0.4 min). The multisensor ac biosusceptometer was reliable to monitor and analyse the in vivo performance of magnetic tablets showing accuracy to quantify disintegration through the magnetic images and to characterize the profile of this process.

  16. Magnetic images of the disintegration process of tablets in the human stomach by ac biosusceptometry

    Oral administration of solid dosage forms is usually preferred in drug therapy. Conventional imaging methods are essential tools to investigate the in vivo performance of these formulations. The non-invasive technique of ac biosusceptometry has been introduced as an alternative in studies focusing on gastrointestinal motility and, more recently, to evaluate the behaviour of magnetic tablets in vivo. The aim of this work was to employ a multisensor ac biosusceptometer system to obtain magnetic images of disintegration of tablets in vitro and in the human stomach. The results showed that the transition between the magnetic marker and the magnetic tracer characterized the onset of disintegration (t50) and occurred in a short time interval (1.1 ± 0.4 min). The multisensor ac biosusceptometer was reliable to monitor and analyse the in vivo performance of magnetic tablets showing accuracy to quantify disintegration through the magnetic images and to characterize the profile of this process

  17. Zigzag Connected Autotransformer-Based 24-pulse AC-DC Converter

    Xiao-qiang, Chen; Hao, Qiu

    2015-02-01

    In this paper, a zigzag connected autotransformer-based 24-pulse AC-DC converter is designed, modeled and simulated to feed direct torque controlled induction motor drives. Winding arrangements and parameters of the autotransformer and interphase reactor are given. Moreover, the design procedure of the autotransformer is modified to make it suitable for retrofit applications. Simulation results indicate that the system is capable of eliminating up to 21st harmonics in the ac mains current. The effect of load variation and load character is also studied to demonstrate the performance and effectiveness of the proposed 24-pulse converters. A set of power quality indices at ac mains and dc side are presented to compare the performance of 6-, 12- and 24-pulse converters.

  18. Autonomous control of interlinking converters in hybrid AC-DC microgrids with energy storages

    Loh, Poh Chiang; Li, Ding; Blaabjerg, Frede

    2011-01-01

    Coexistence of both ac and dc sub-grids in a hybrid microgrid is likely given that modern distributed sources can either be ac or dc. Linking these sub-grids are power converters, whose topological configuration should preferably be not too unconventional to avoid unnecessary compromises in...... reliability. The desired operating features should therefore be introduced to the interlinking converters through control design with overall system simplicity still preserved for industry relevance. This concern is now addressed here through the development of an appropriate scheme for controlling the...... interlinking converters, so as to achieve autonomous control for the overall hybrid microgrid. Features achieved include proportional active power sharing among the distributed sources based on their ratings and not placements within the hybrid microgrid, and proper reactive power sharing within the ac sub...

  19. Simulation of an ac electro-osmotic pump with step microelectrodes

    Kim, Byoung Jae; Lee, Seung-Hyun; Rezazadeh, Soghra; Sung, Hyung Jin

    2011-05-01

    Pumps with step microelectrodes subjected to an ac voltage are known to have faster pumping rates than those with planar asymmetric microelectrodes. The driving force for pumping in these systems is ac electro-osmosis. This paper aims to understand the flow behaviors of pumps with step microelectrodes by using a realistic model applicable to high external voltages. This model takes the steric effect due to the finite sizes of ions into account and copes with the exponential sensitivity of the counterion concentration to voltage. The effects on the pumping flow rate of varying the pump parameters were investigated. The geometrical parameters were optimized, and the effects of varying the ac frequency and amplitude were examined. The electrical potential of the fluid and the electrical charge at the electrode surface were solved simultaneously, and the Stokes equation was used to describe the fluid flow.

  20. Entanglement Dynamics of Strongly-AC-Driven Superconducting Qubits in Circuit QED

    施振刚; 谌雄文; 文伟; 向少华; 宋克慧

    2011-01-01

    We study the entanglement dynamics between two strongly-AC-driven superconducting charge qubits coupled collectively to a zero temperature, dissipative resonator and find an unusual feather that the competing of creation and annihilation of entanglement can lead to entanglement increasing, sudden death and revival. We also calculate the dependence of the death time on the initial state of the system.

  1. Advantages of Square-Root Extended Kalman Filter for Sensorless Control of AC Drives

    Šmídl, Václav; Peroutka, Z.

    2012-01-01

    Roč. 59, č. 11 (2012), s. 4189-4196. ISSN 0278-0046 Institutional research plan: CEZ:AV0Z10750506 Institutional support: RVO:67985556 Keywords : Kalman filters * Mathematical model * AC motors Subject RIV: BC - Control Systems Theory Impact factor: 5.165, year: 2012 http://library.utia.cas.cz/separaty/2012/AS/smidl-0436868.pdf

  2. ac Stark gradient echo memory in cold atoms

    The burgeoning fields of quantum computing and quantum key distribution have created a demand for a quantum memory. The gradient echo memory scheme is a quantum memory candidate for light storage that can boast efficiencies approaching unity, as well as the flexibility to work with either two- or three-level atoms. The key to this scheme is the frequency gradient that is placed across the memory. Currently, the three-level implementation uses a Zeeman gradient and warm atoms. In this article we model an alternate gradient-creation mechanism--the ac Stark effect--to provide an improvement in the flexibility of gradient-creation and field-switching times. We propose this scheme in concert with a move to cold atoms (≅1 mK). These temperatures would increase the storage times possible, and the small ensemble volumes would enable large ac Stark shifts with reasonable laser power. We find that memory bandwidths on the order of MHz can be produced with experimentally achievable laser powers and trapping volumes, with high precision in gradient creation and switching times on the order of nanoseconds possible. By looking at the different decoherence mechanisms present in this system, we determine that coherence times on the order of tens of milliseconds are possible, as are delay-bandwidth products of approximately 50 and efficiencies over 90%.

  3. Long-range response in ac electricity grids.

    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)EPJBFY1434-602810.1140/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)1951-635510.1140/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. PMID:27575148

  4. Memory Convergence and Optimization with Fuzzy PSO and ACS

    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.

  5. AcMNPV As A Model for Baculovirus DNA Replication

    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.

  6. Soliton ratchetlike dynamics by ac forces with harmonic mixing

    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...... numerically and the results are compared with a perturbation analysis based on a point-particle representation of the soliton. We find that first order perturbative calculations lead to incomplete descriptions, due to the important role played by the soliton-phonon interaction in establishing the phenomenon...... mechanism, while for biharmonic drivers with even harmonic superposition, also a point-particle contribution to the drift velocity is present. The phenomenon is robust enough to survive the presence of thermal noise in the system and can lead to several interesting physical applications....

  7. DC System Control Strategy for 500 kV AC Line Automatic Reclosing in China-Russia Back to Back Project%中国—俄罗斯背靠背联网工程500 kV交流出线具有自动重合闸的直流控制策略

    马为民; 曹燕明; 蒋维勇

    2013-01-01

    为提高中俄直流联网黑河换流站跨国联网工程运行的可靠性,提出了修改故障期间直流控制策略的方案,以使工程原设计方案中未设置的自动重合闸功能恢复使用.采用EMTDC仿真软件建立模型进行典型工况计算,并对重合闸期间产生的交流母线过电压、交流母线避雷器和阀避雷器的耐受能力进行了校核比较.仿真结果表明,新的控制策略应限制故障期间功率水平在300 MW(标幺值为0.4)以内.修改后的控制策略在黑河换流站实施后,通过兴福变至黑河变(兴黑线)故障后重合闸的实践检验,证明了策略的可行性和可靠性.所得出的直流控制策略对研究弱交流系统条件下换流站仅有1回交流出线时采用自动重合闸功能有重要指导意义.%To improve the operation reliability of Heihe converter station at China-Russia back to back(BTB) project,we proposed a modified DC system control strategy during line faults in order to recover the automatic reclosing function,which was not adopted in original design of the project.Models of the software EMTDC were used to simulate typical cases,through which the AC bus's over-voltage and the arrester energy of AC bus arrester and valve arrester during faults were compared and checked.The simulation results show that,from the new strategy,the power at the level of 300 MW (0.4 in per unit value) should be limited during a line fault.Feasibility and reliability of the modified control strategy have been proved by the successful reclosing in HeiHe station with the proposed strategy implemented under a failure on Xingfu Station to Heihe Station(Xinghei line) section.Thus the proposed DC control strategy is proven to be of great significance for studying the adopting automatic reclosing function in future converter station with only one AC line under weak AC system condition.

  8. Implementation of Low Frequency Ac to High Frequency Ac with Single Stage Zvs-Pwm Inverter

    S. Arumugam S. Ramareddy M. Sridhar

    2011-12-01

    Full Text Available This paper presents a novel soft-switching pulse width modulation (PWM utility frequency AC to high frequency (HF AC power conversion circuit incorporating boost-active clamp single stage inverter topology. This power converter is more suitable and acceptable for cost effective HF consumer induction heating applications. Its operating principle is presented. The operating performances of this high frequency inverter using the latest insulated gate bipolar transistors are illustrated, which includes HFAC power regulation ranges and actual efficiency characteristics based on zero voltage soft switching operation ranges.. The simulation circuits are models are developed and they are simulated using ORCAD.

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

    Full Text Available [ Credit s ] BLAST Search Image Search Home About Archive Update History Contact us AcEST AcEST C ... c.jp/togodb/view/archive_acestcontig#en Data acquisit ion method - Data analysis method - Number of data ... entries 4,298 entries Data it em Description Contig ID ID of contig sequence of A ... ris Number of clones The number of EST clones constit uting the contig sequence of Adiantum capillus-vene ... ris Definit ion Definit ion Link to clone list In the TogoDB edi ...

  10. Realization of a Direct Soft Switching AC/AC Converter for Wireless Power Transfer Applications

    Vuorsalo, Simo

    2015-01-01

    This thesis describes the design, realization and testing of a three-phase to one-phase direct AC/AC converter, also known as the matrix converter. The switching is using the soft-switching strategy which is also known in the literature as the Zero Current Switching strategy. To achieve ZCS, the circuit needs resonant behavior which is achieved by the transmitter primary side that is an LC circuit. This circuit acts as a tank circuit and the switching frequency is the resonant frequency of th...

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

    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...... low cost alternative to sensitive applications that need to ride-through frequent input voltage sags. For confirming the converter performance, experimental testing using a constructed laboratory prototype is performed with its captured results presented in a later section of the paper....

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

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

    2009-01-01

    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...... semiconductor commutations, and hence, no increase in switching losses. The proposed converter therefore offers a low-cost alternative to applications that need to ride through frequent input voltage sags. For confirming the converter performance, experimental testing using a constructed laboratory prototype is...

  13. ChAcNLS, a Novel Modification to Antibody-Conjugates Permitting Target Cell-Specific Endosomal Escape, Localization to the Nucleus, and Enhanced Total Intracellular Accumulation.

    Beaudoin, Simon; Rondeau, Andreanne; Martel, Olivier; Bonin, Marc-Andre; van Lier, Johan E; Leyton, Jeffrey V

    2016-06-01

    The design of antibody-conjugates (ACs) for delivering molecules for targeted applications in humans has sufficiently progressed to demonstrate clinical efficacy in certain malignancies and reduced systemic toxicity that occurs with standard nontargeted therapies. One area that can advance clinical success for ACs will be to increase their intracellular accumulation. However, entrapment and degradation in the endosomal-lysosomal pathway, on which ACs are reliant for the depositing of their molecular payload inside target cells, leads to reduced intracellular accumulation. Innovative approaches that can manipulate this pathway may provide a strategy for increasing accumulation. We hypothesized that escape from entrapment inside the endosomal-lysosomal pathway and redirected trafficking to the nucleus could be an effective approach to increase intracellular AC accumulation in target cells. Cholic acid (ChAc) was coupled to the peptide CGYGPKKKRKVGG containing the nuclear localization sequence (NLS) from SV-40 large T-antigen, which is termed ChAcNLS. ChAcNLS was conjugated to the mAb 7G3 (7G3-ChAcNLS), which has nanomolar affinity for the cell-surface leukemic antigen interleukin-3 receptor-α (IL-3Rα). Our aim was to determine whether 7G3-ChAcNLS increased intracellular accumulation while retaining nanomolar affinity and IL-3Rα-positive cell selectivity. Competition ELISA and cell treatment assays were performed. Cell fractionation, confocal microscopy, flow cytometry, and Western blot techniques were used to determine the level of antibody accumulation inside cells and in corresponding nuclei. In addition, the radioisotope copper-64 ((64)Cu) was also utilized as a surrogate molecular cargo to evaluate nuclear and intracellular accumulation by radioactivity counting. 7G3-ChAcNLS effectively escaped endosome entrapment and degradation resulting in a unique intracellular distribution pattern. mAb modification with ChAcNLS maintained 7G3 nM affinity and produced high

  14. Quasienergy spectrum and tunneling current in ac-driven triple quantum dot shuttles

    Villavicencio, J [Facultad de Ciencias, Universidad Autonoma de Baja California, Ensenada (Mexico); Maldonado, I [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada (Mexico); Cota, E [Centro de Nanociencias y Nanotecnologia, Universidad Nacional Autonoma de Mexico, Ensenada (Mexico); Platero, G, E-mail: villavics@uabc.edu.mx [Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, 28049 Madrid (Spain)

    2011-02-15

    The dynamics of electrons in ac-driven double quantum dots have been extensively analyzed by means of Floquet theory. In these systems, coherent destruction of tunneling has been shown to occur for certain ac field parameters. In this work we analyze, by means of Floquet theory, the electron dynamics of a triple quantum dot in series attached to electric contacts, where the central dot position oscillates. In particular, we analyze the quasienergy spectrum of this ac-driven nanoelectromechanical system as a function of the intensity and frequency of the ac field and of external dc voltages. For strong driving fields, we derive, by means of perturbation theory, analytical expressions for the quasienergies of the driven oscillator system. From this analysis, we discuss the conditions for coherent destruction of tunneling (CDT) to occur as a function of detuning and field parameters. For zero detuning, and from the invariance of the Floquet Hamiltonian under a generalized parity transformation, we find analytical expressions describing the symmetry properties of the Fourier components of the Floquet states under such a transformation. By using these expressions, we show that in the vicinity of the CDT condition, the quasienergy spectrum exhibits exact crossings which can be characterized by the parity properties of the corresponding eigenvectors.

  15. Cost effective second generation AC-modules: Development and testing aspects

    In the framework of the European research project PV2GO, a new AC-module inverter was developed, taking into account all relevant aspects from a European market's point of view (standards, market, application, and research and development goals). The project goal was to achieve the overall system costs of 3 Euro per Wp for a modular plug-and-play photovoltaic system. For the photovoltaic-module, a standard 130-Wp Eurosolare module was chosen. The research and development (R and D) goal was to develop an advanced DC-control system consisting of a state-of-the-art programmable digital device and an Application Specific Integrated Circuit (ASIC) for the AC-control of the inverter. According to the topology concept, thermal and magnetic designs were optimized with regard to production technology and packaging for large-scale production. The new AC-modules were tested in a number of field-test sites in various parts of Europe and their reliability was assessed through Highly Accelerated Stress Tests. Efficiency and power quality have been tested in the laboratory. Further in the PV2GO project an optimization study of the manufacturing process of the new generation of AC-modules for high volume output was done. Another task was the pre-certification procedure to assure compliance with the European guidelines and standards

  16. Development of a low-cost integrated 20-kW ac solar tracking sub- array for grid-connected PV power system applications. Phase 1, Annual technical report, 11 July 1995--31 July 1996

    Stern, M.; West, R.; Fourer, G.; Whalen, W.; Van Loo, M.; Duran, G. [Utility Power Group, Chatsworth, CA (United States)

    1997-06-01

    The overall goal of this effort is to reduce the installed cost of utility scale grid connected photovoltaic power systems. The focus of the effort is on ``BOS`` (Balance-Of-System) component manufacturing technology, which essentially involves all PV power system engineering, manufacturing, assembly and construction tasks from the receipt of a PV module to the deliver of grid connected electricity.

  17. Dicty_cDB: FCL-AC03 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC03 (Link to dictyBase) - - - Contig-U16477-1 FCL-AC03P ...(Link to Original site) FCL-AC03F 538 FCL-AC03Z 570 FCL-AC03P 1108 - - Show FCL-AC03 Library FCL (Link to library) Clone ID FCL-...7-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC03Q....Seq.d/ Representative seq. ID FCL-AC03P (Link to Original site) Representative DNA sequence >FCL-AC03 (FCL-AC03Q) /CSM/FCL/FCL-...AC/FCL-AC03Q.Seq.d/ AATTTTTAAAAAAAAAAGAAAATAAAAAAAAAAATAATATTTTATTAGTCATTATAAAAT TGTGAAT

  18. Dicty_cDB: FCL-AC20 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC20 (Link to dictyBase) - - - Contig-U15117-1 FCL-AC20Z ...(Link to Original site) - - FCL-AC20Z 600 - - - - Show FCL-AC20 Library FCL (Link to library) Clone ID FCL-A... http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC20Q.Seq.d/ Representative seq. ID FCL-...AC20Z (Link to Original site) Representative DNA sequence >FCL-AC20 (FCL-AC20Q) /CSM/FCL/FCL-AC/FCL-...Homology vs CSM-cDNA Score E Sequences producing significant alignments: (bits) Value FCL-AC20 (FCL-AC20Q) /CSM/FCL/FCL-AC/FCL-

  19. Levantamiento del campo acústico de una fuente sonora subacuática en el tanque hidroacústico del Instituto de Acústica

    Ranz Guerra, Carlos; Cobo, Pedro

    2000-01-01

    6 pp.-- PACS nrs.: 43.30.Jx, 43.30.Sf.-- Comunicación presentada en los siguientes congresos: Acústica 2000, II Congreso Iberoamericano de Acústica. XXXI Congreso Nacional de Acústica: TecniAcústica 2000. II Congreso Ibérico de Acústica. II Jornadas Iberoamericanas de Acústica. EAA Symposium on Architectural Acoustics.

  20. Mapa acústico parcial de Benetusser

    MORILLA CASTELLANOS, EMILIO

    2012-01-01

    Se establece el mapa de ruido del municipio de Benetússer para evaluar y conocer su exposición al ruido ambiental y así poder dar cumplimiento a la Directiva Europea sobre Gestión y Evaluación de Ruido Ambiental (2002/49/CE) y a la Ley nacional 37/2003 del Ruido. Los mapas estratégicos de ruido nos aportan la información fundamental para diagnosticar la situación acústica y para la gestión del ruido ambiental.

  1. An ac biased superconducting flux transformer

    The coupled motion of the vortex lattice of two electrically insulated, superimposed, superconducting thin films (primary and secondary) in a perpendicular magnetic field, is predicted to exhibit a Josephson-like behavior. For a dc applied current flowing in the primary film, the voltage difference between the time-averaged primary and secondary flux flow voltages obeys the equations of a resistively shunted junction model. If an ac current is superimposed on the dc current. Shapiro-type steps are predicted in the current-voltage characteristic. In contrast to the conventional Josephson effect, the voltage positions of these steps can be tuned by the applied magnetic field. (orig.)

  2. Team-oriented Adaptive Droop Control for Autonomous AC Microgrids

    Shafiee, Qobad; Nasirian, Vahidreza; Guerrero, Josep M.; L. Lewis, Frank; Davoudi, Ali

    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...... 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. The...... proposed controllers are fully distributed; i.e., each source requires information exchange with only a few other sources, those in direct contact through the communication infrastructure. A Microgrid test bench is used to verify the proposed controlmethodology, where different test scenarios such as load...

  3. Dc and ac Josephson effects in a granular material

    This paper reports on three-dimensional systems of point contacts that were prepared by pressing together Niobium grains of about 100 μm diameter inside a sapphire cylinder. Current-voltage characteristics were studied in dependence of temperature and, in addition, of the power of incident microwaves (X-bank). The results are similar to those established for a single weak link junction. Only for small currents the sample showed different behavior. The inverse a.c. Josephson effect was observed. The measured d.c. voltage shows and alternating temperature dependence which might be expected following the calculations of J.J. Chang for a weak link of small capacity and small resistance

  4. Resistojet control and power for high frequency ac buses

    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.

  5. Estudio acústico del Conservatorio de Piles

    VILLA MORANT, SARA

    2014-01-01

    El objetivo de este proyecto es realizar un estudio acústico general de la "Casa de la Cultura" de Piles, sobre todo de los recintos que más lo requieren, como la sala principal de música. El edificio, al tratarse de una construcción antigua, no reúne las especificaciones acústicas establecidas en el Código Técnico vigente en la actualidad. En primer lugar, se realiza el estudio del acondicionamiento acústico de la sala principal, entendiéndose como acondicionamiento acústico la definición de...

  6. AC Own Motion Percentage of Randomly Sampled Cases

    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...

  7. AC electric motors control advanced design techniques and applications

    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

  8. Study of AC electrical conduction mechanisms in an epoxy polymer

    Jilani, Wissal; Mzabi, Nissaf; Gallot-Lavallée, Olivier; Fourati, Najla; Zerrouki, Chouki; Zerrouki, Rachida; Guermazi, Hajer

    2015-11-01

    The AC conductivity of an epoxy resin was investigated in the frequency range 10^{-1} - 106 Hz at temperatures ranging from -100 to 120 °C. The frequency dependence of σ_{ac} was described by the law: σ_{ac}=ω \\varepsilon0\\varepsilon^''_{HN}+Aωs. The study of temperature variation of the exponent (s) reveals two conduction models: the AC conduction dependence upon temperature is governed by the small polaron tunneling mechanism (SPTM) at low temperature (-100 -60 °C) and the correlated barrier hopping (CHB) model at high temperature (80-120 °C).

  9. An improved AC-amplifier for electrophysiology

    Jorgovanović Nikola

    2009-01-01

    Full Text Available We present the design, simulation and test results of a new AC amplifier for electrophysiological measurements based on a three op-amp instrumentation amplifier (IA. The design target was to increase the common mode rejection ratio (CMRR, thereby improving the quality of the recorded physiological signals in a noisy environment. The new amplifier actively suppresses the DC component of the differential signal and actively reduces the common mode signal in the first stage of the IA. These functions increase the dynamic range of the amplifier's first stage of the differential signal. The next step was the realization of the amplifier in a single chip technology. The design and tests of the new AC amplifier with a differential gain of 79.2 dB, a CMRR of 130 dB at 50 Hz, a high-pass cutoff frequency at 0.01 Hz and common mode reduction in the first stage of the 49.8 dB are presented in this paper.

  10. CartiGenea®-AC: A Mesenchymal stem cells enriched Autologous Chondrocytes for the Treatment of patients with cartilaginous defects on a New Drug-Cell Combinatory Effect Prediction Algorithm on the Cell Based on Chondro defects Gene Expression and Dose-Response Curve.

    Grigoriadis Ioannis

    2015-01-01

    CartiGenea®-AC: Chondrocytes, the predominant cell type within AC, synthesize matrix components. Because AC lacks a major vascular supply, lymphatic drainage, and nervous system innervation, chondrocytes function under avascular, anaerobic conditions, obtaining nutrients by diffusion from synovial fluid. Within AC, metabolic and morphologic profiles of deep-zone chondrocytes are distinct from those populating the superficial tangential zone. The factors responsible for this variation are ...

  11. 直流调制策略改善交直流混联系统的频率稳定性研究%Improving Frequency Stability of Parallel AC-DC Hybrid Systems by Power Modulation Strategy of HVDC Link

    朱红萍; 罗隆福

    2012-01-01

    为了抑制交直流混联系统的负荷突变而引起交流系统的频率振荡,提出变结构的直流功率调制和快速汽门最优控制的协调控制策略。首先建立交直流系统的简化模型,通过交叠分解的方法将模型分解为2个独立的子系统,对子系统采用直流功率的变结构控制,切换函数采用最优控制设计。该控制策略实现简单,能显著减少频率偏差的首摆峰值,但稳态误差较大。因此采用发电机的快速汽门最优控制来协调控制频率,采用线性最优理论设计快速汽门综合控制器。对采用这2种控制器的输电系统,在负荷发生扰动的情况下进行仿真。结果表明,变结构的直流调制在扰动发生的初期能显著抑制频率振荡,汽轮发电机的调速器与直流功率调制器相结合,减少了稳态误差。%In order to suppress frequency oscillatory when an interconnected AC and DC system is subjected to a load shedding in one area of AC system, the coordination of variable structure control of DC power modulation and turbine-generator steam valve optimization was presented. At first, the simplified model of AC/DC hybrid system was established which was divided into two independent subsystem by adopting overlap decomposition, and then put forward a linear variable structure control of DC power modulation, switching function of variable structure control was establishedby applying optimal control theory. Although the controller decreases the peak of the first swing significantly and is easy to realize, the steady state error is large. To solve the problem, the concept of coordinated control of DC power modulation and fast steam valve optimal control of governor was established. The steam valve controller was studied with linear optimal control theory. Simulation experiments were conducted for the purpose of applying two kinds of control mode under the condition of load disturbance. The result shows the

  12. AC-DC integrated load flow calculation for variable speed offshore wind farms

    Zhao, Menghua; Chen, Zhe; Blaabjerg, Frede

    2005-01-01

    This paper proposes a sequential AC-DC integrated load flow algorithm for variable speed offshore wind farms. In this algorithm, the variable frequency and the control strategy of variable speed wind turbine systems are considered. In addition, the losses of wind turbine systems and the losses of...... converters are also integrated into the load flow algorithm. As a general algorithm, it can be applied to different types of wind farm configurations, and the load flow is related to the wind speed....

  13. Dicty_cDB: FCL-AC29 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC29 (Link to dictyBase) - - - Contig-U15392-1 FCL-AC29P ...(Link to Original site) FCL-AC29F 104 FCL-AC29Z 591 FCL-AC29P 695 - - Show FCL-AC29 Library FCL (Link to library) Clone ID FCL-...-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC29Q....Seq.d/ Representative seq. ID FCL-AC29P (Link to Original site) Representative DNA sequence >FCL-AC29 (FCL-AC29Q) /CSM/FCL/FCL-...roducing significant alignments: (bits) Value VSC293 (VSC293Q) /CSM/VS/VSC2-D/VSC293Q.Seq.d/ 1063 0.0 FCL-AC29 (FCL-

  14. Application of PEI–K2CO3/AC for capturing CO2 from flue gas after combustion

    Highlights: • A novel PEI–K2CO3/AC sorbent was prepared with the co-impregnation method. • The coupling characteristics of PEI and K2CO3 in the sorbent are expounded. • Both PEI and K2CO3 contribute to the total CO2 capture capacity of PEI–K2CO3/AC. • PEI–K2CO3/AC presents high CO2 capture capacity and long-term stability. • PEI–K2CO3/AC should be considered as a new option for post-combustion CO2 capture. - Abstract: The capture of CO2 from flue gas after combustion using solid sorbents is one of the efficient options for reducing CO2 emissions from fossil fuel-fired power plants. To satisfy the requirement of large quantities flue gas treatment, the CO2 capture capacities of the solid sorbents must be focused on. In order to obtain a sorbent with high CO2 capture capacity, a novel PEI–K2CO3/AC sorbent was prepared by impregnating potassium carbonate (K2CO3) and polyethylenimine (PEI) on activated carbon (AC) in this work. The CO2 capture performance of this sorbent was investigated using a fixed bed reactor system. The CO2 capture capacity of PEI–K2CO3/AC with the total K2CO3 and PEI loadings of 50 wt% was measured as 3.60 mmol CO2/g under the condition of 60 °C, 8% CO2 + 10% H2O. In addition, this sorbent is proved to be regenerable and stable during 5 cycle CO2 sorption–desorption tests. Compared with K2CO3/AC (loading of 58 wt%) and PEI/AC (loading of 43 wt%), PEI–K2CO3/AC presents higher CO2 capture capacity and long-term stability. Therefore, PEI–K2CO3/AC should be considered as a new option for capturing CO2 from flue gas after combustion

  15. Septic Systems, DVS received database from FW/AC BofH, geocoded to map, plan for elimination as possible, Published in 2006, 1:24000 (1in=2000ft) scale, City of Fort Wayne.

    NSGIC GIS Inventory (aka Ramona) — This Septic Systems dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 2006. It is described as 'DVS...

  16. Magnetic Nanoparticle Thermometer: An Investigation of Minimum Error Transmission Path and AC Bias Error

    Zhongzhou Du

    2015-04-01

    Full Text Available The signal transmission module of a magnetic nanoparticle thermometer (MNPT was established in this study to analyze the error sources introduced during the signal flow in the hardware system. The underlying error sources that significantly affected the precision of the MNPT were determined through mathematical modeling and simulation. A transfer module path with the minimum error in the hardware system was then proposed through the analysis of the variations of the system error caused by the significant error sources when the signal flew through the signal transmission module. In addition, a system parameter, named the signal-to-AC bias ratio (i.e., the ratio between the signal and AC bias, was identified as a direct determinant of the precision of the measured temperature. The temperature error was below 0.1 K when the signal-to-AC bias ratio was higher than 80 dB, and other system errors were not considered. The temperature error was below 0.1 K in the experiments with a commercial magnetic fluid (Sample SOR-10, Ocean Nanotechnology, Springdale, AR, USA when the hardware system of the MNPT was designed with the aforementioned method.

  17. Lagrangian structures, integrability and chaos for 3D dynamical equations[45.20.Jj Lagrangian and Hamiltonian mechanics; 02.30.Ik Integrable systems; 05.45.Ac Low-dimensional chaos;

    Bustamante, Miguel D [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile (Chile); Hojman, Sergio A [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile (Chile)

    2003-01-10

    In this paper, we consider the general setting for constructing action principles for three-dimensional first-order autonomous equations. We present the results for some integrable and non-integrable cases of the Lotka-Volterra equation, and show Lagrangian descriptions which are valid for systems satisfying Shil'nikov criteria on the existence of strange attractors, though chaotic behaviour has not been verified up to now. The Euler-Lagrange equations we get for these systems usually present 'time reparametrization' invariance, though other kinds of invariance may be found according to the kernel of the associated symplectic 2-form. The formulation of a Hamiltonian structure (Poisson brackets and Hamiltonians) for these systems from the Lagrangian viewpoint leads to a method of finding new constants of the motion starting from known ones, which is applied to some systems found in the literature known to possess a constant of the motion, to find the other and thus showing their integrability. In particular, we show that the so-called ABC system is completely integrable if it possesses one constant of the motion.

  18. AC susceptibility of Sr2RuO4-Sr3Ru2O7 eutectics: Dependence on AC field strength and frequency

    The low-field AC susceptibility of a eutectic crystal of the Sr2RuO4-Sr3Ru2O7 system exhibits superconducting transition features at three temperatures. We investigate the dependence on AC field strength from 0.021 to 2.1 Oe-rms and frequency from 17 to 3 kHz. The two lower-temperature peaks in the imaginary part originate in the Sr3Ru2O7 part. The lowest-temperature peak is exceedingly sensitive to the field amplitude and shifts to lower temperatures with increasing amplitude. By contrast, it slightly shifts to higher temperatures with increasing frequency. These results support that the sensitive features involve weak links forming the screening paths

  19. Low-energy hydraulic fracturing wastewater treatment via AC powered electrocoagulation with biochar.

    Lobo, Fernanda Leite; Wang, Heming; Huggins, Tyler; Rosenblum, James; Linden, Karl G; Ren, Zhiyong Jason

    2016-05-15

    Produced and flowback waters are the largest byproducts associated with unconventional oil and gas exploration and production. Sustainable and low cost technologies are needed to treat and reuse this wastewater to avoid the environmental problems associated with current management practices (i.e., deep well injection). This study presents a new process to integrate AC-powered electrocoagulation (EC) with granular biochar to dramatically reduce energy use and electrode passivation while achieving high treatment efficiency. Results show achieving a 99% turbidity and TSS removal for the AC-EC-biochar system only used 0.079 kWh/m(3) or 0.15 kWh/kg TSS, which is 70% lower than traditional DC-EC systems and orders of magnitude lower than previous studies. The amount of biochar added positively correlates with energy saving, and further studies are needed to improve organic carbon and salt removal through system integration. PMID:26894291

  20. The considerations to use soft start AC controllers in nuclear application

    Motors larger than 200 HP shall be fed from 4.16 kV or 2.4 kV fused starters. In CANDU reactors all large pumps motors are supplied directly from the 13.8 kV, 6.3 kV or 4.16 kV AC system. In the MAPLE reactors, the Primary Coolant System pumps are supplied directly from the 2.4 kV AC system. Starting and stopping a pump may be easy, but the consequences may not always be ones we wanted. It can result in high start current that require large cables and fuses, or hydraulic shocks known as 'water hammer' can cause stress and damage to pipes, valves, gaskets and seals. If the nuclear plant installs soft starters, the result will be pump protection, which provides start and stop control, preventing both water hammer and expensive high start currents. (author)

  1. Robust Timing Synchronization for AC-OFDM Based Optical Wireless Communications

    Ranjha, Bilal A; Kavehrad, Mohsen; Deng, Peng

    2015-01-01

    Visible light communications (VLC) have recently attracted a growing interest and can be a potential solution to realize indoor wireless communication with high bandwidth capacity for RF-restricted environments such as airplanes and hospitals. Optical based orthogonal frequency division multiplexing (OFDM) systems have been proposed in the literature to combat multipath distortion and intersymbol interference (ISI) caused by multipath signal propagation. In this paper, we present a robust timing synchronization scheme suitable for asymmetrically clipped (AC) OFDM based optical intensity modulated direct detection (IM/DD) wireless systems. Our proposed method works perfectly for ACO-OFDM, Pulse amplitude modulated discrete multitone (PAM-DMT) and discrete Hartley transform (DHT) based optical OFDM systems. In contrast to existing OFDM timing synchronization methods which are either not suitable for AC OFDM techniques due to unipolar nature of output signal or perform poorly, our proposed method is suitable for...

  2. Structure-guided creation of AcAP5-derived and platelet targeted factor Xa inhibitors.

    Zhu, Yuanjun; Lin, Yuan; Liu, Aihua; Shui, Mengyang; Li, Ruyi; Liu, Xiaoyan; Hu, Wenhui; Wang, Yinye

    2015-06-15

    Anticoagulants and anti-platelet agents are simultaneously administrated in clinical practice (i.e. percutaneous coronary intervention), which cause significant risk of systemic bleeding. Targeted delivery of anticoagulants to the activated platelets at sites of vascular injuries may condense the site-specific anticoagulant effect and reduce the hemorrhage side effects in uninjured vessels. To this end, we prepared three ancylostoma caninum anticoagulant peptide 5 (AcAP5) variants NR1, NR2 and NR3 engineered with a platelet-binding Arg-Gly-Asp (RGD) motif and evaluated their anti-Factor Xa (FXa) and platelet-binding effects. These RGD-containing AcAP5 variants were capable of interacting with platelet receptor αIIbβ3 as shown in computational analysis. All variants, especially NR2 and NR3, retained entirely the anti-FXa function of parent AcAP5. Moreover, they prevented the formation of occlusive thrombi in rat carotid artery injury model, suggesting that they inhibit platelet aggregation in vivo. Further functional investigation of NR3 demonstrated that NR3 inhibited platelet aggregation in vitro and FXa activity in vivo, and prolonged the coagulation time, all in a dose-dependent manner. Through flow cytometry assay, we confirmed the binding of NR3 to αIIbβ3 receptor. In mouse model of carotid artery endothelium injury, NR3-treated mice showed less tail bleeding time than AcAP5-treated mice, and aspirin plus NR3 treatment exhibited moderate reduction of blood loss compared with aspirin plus AcAP5 treatment. These results indicate the feasibility to engineer a novel FXa inhibitor specifically targeting the activated platelets, which centralizes its anticoagulation efficacy in the injured vascular endothelium and reduces the risk of systemic bleeding. PMID:25887920

  3. Loss comparison of different nine-switch and twelve-switch energy conversion systems

    Bahman, Amir Sajjad; Loh, Poh Chiang; Qin, Zian;

    2014-01-01

    answer only available after performing a thorough analysis. For that, it is the intention now to compare the nine-switch and twelve-switch converters when they are used in ac-ac, ac-dc, dc-ac or dc-dc energy conversion systems. Their losses will be compared to identify when the nine-switch converter will...

  4. Spectroscopic AC Susceptibility Imaging (sASI) of Magnetic Nanoparticles

    Ficko, Bradley W.; Nadar, Priyanka M.; Diamond, Solomon G.

    2014-01-01

    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 measurement 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 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 (R2 = 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 (R2 = 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 (R2 = 0.97, p <0.001). These results demonstrate the concept of ASI and advantages of sASI. PMID:25477704

  5. Mapa Acústico del Gran Madrid

    Santiago Páez, José Salvador; Perera, P

    2006-01-01

    El desarrollo urbanístico de Madrid desde los años 1980 a finales de la década de los 90 hizo que su Ayuntamiento, que ya había promovido la realización entre 1985 y 1991 de un Mapa Acústico parcial de la ciudad, pensase en extender el ámbito de éste a todo el término municipal. Siguiendo el mismo criterio anterior, se superpuso una cuadrícula sobre el plano de Madrid, y se llevaron a cabo registros sonoros de 5 minutos en cada vértice de la misma, en los puntos de medición fuera del área ant...

  6. Josephson arrays for dc and ac metrology

    Large series arrays of underdamped SIS tunnel junctions are the basic element of the primary dc voltage standards used at present. The development of versatile quantum voltmeters for dc and ac metrology requires the preparation of large and perfect series arrays of overdamped Josephson junctions. Overdamped junctions can be realized by externally shunted SIS junctions or by internally shunted SNS or SINIS junctions. Arrays of up to 8000 SINIS junctions or 30000 SNS junctions were successfully operated at the 1 V dc level. In addition to being used in large arrays for voltage metrology and oscillators, the described junction types may become very useful for the preparation of highly integrated single-flux-quantum digital devices. (author)

  7. An ac bridge readout for bolometric detectors

    Rieke, F. M.; Lange, A. E.; Beeman, J. W.; Haller, E. E.

    1989-01-01

    The authors have developed a bolometer readout circuit which greatly improves the low-frequency stability of bolometric detectors. The circuit uses an ac bias voltage and two matched bolometers and allows stable dc bolometer operation for integration times greater than 10 s. In astronomical applications the readout allows for qualitatively different observation modes (e.g. staring or slow-drift scanning) which are particularly well suited for space observations and for the use of arrays. In many applications the readout can increase sensitivity. The authors present noise spectra for 4He temperature bolometers with no excess noise at frequencies greater than 0.1 Hz. The measured optical responsivity of a bolometer operated with the present readout is the same as that of a bolometer operated with a conventional readout.

  8. Composite Based EHV AC Overhead Transmission Lines

    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......) levels are still not seen as possibility, the future expansion of transmission grids are dependent on new solutions with lessened environment impact, especially with regard to the visual impact. In the present Thesis, composite materials and composite based overhead line components are presented 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...

  9. Effective ac response in weakly nonlinear composites

    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.

  10. Modeling of long High Voltage AC Underground

    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...... cable models, perform highly accurate field measurements for validating the model and identifying possible disadvantages of the cable model. Furthermore the project suggests and implements improvements and validates them against several field measurements. It is shown in this paper how a new method for...... calculating the frequency dependent cables impedance greatly improves the modeling procedure and gives a highly accurate result for high frequency simulations....

  11. Ac-driven vortex-antivortex dynamics in nanostructured superconductor-ferromagnetic hybrids

    The dynamics of ac-driven vortices and antivortices in a superconducting film interacting with an array of magnetic dipoles on top is investigated via hybrid molecular dynamics-Monte Carlo simulations. The dipole array considered in this study is capable to stabilize in equilibrium vortex-antivortex pairs. The appearance of a net electric field out of the ac excitation demonstrates that this system behaves as a voltage rectifier. Because of the asymmetric nature of the effective pinning potential generated by the dipole array, the ac-driven vortices and antivortices are ratcheted in opposite directions, thereby contributing additively to the observed net voltage. In addition, for high frequency values, the dc electric field-ac amplitude curves present a series of steps. A careful analysis of the time series of the electric field and number of vortex-antivortex (v-av) pairs reveals that these steps are related to mode-locking between the drive frequency and the number of v-av creation-annihilation events.

  12. Fiber - Optic Devices as Temperature Sensors for Temperature Measurements in AC Magnetic Fields

    Rablau, Corneliu; Lafrance, Joseph; Sala, Anca

    2007-10-01

    We report on the investigation of several fiber-optic devices as potential sensors for temperature measurements in AC magnetic fields. Common temperature sensors, such as thermocouples, thermistors or diodes, will create random and/or systematic errors when placed in a magnetic field. A DC magnetic field is susceptible to create a systematic offset to the measurement, while in an AC magnetic field of variable frequency random errors which cannot be corrected for can also be introduced. Fiber-Bragg-gratings and thin film filters have an inherent temperature dependence. Detrimental for their primary applications, the same dependence allows one to use such devices as temperature sensors. In an AC magnetic field, they present the advantage of being immune to electromagnetic interference. Moreover, for fiber-Bragg-gratings, the shape factor and small mass of the bare-fiber device make it convenient for temperature measurements on small samples. We studied several thin-film filters and fiber-Bragg-gratings and compared their temperature measurement capabilities in AC magnetic fields of 0 to 150 Gauss, 0 to 20 KHz to the results provided by off-the-shelf thermocouples and thermistor-based temperature measurement systems.

  13. A novel wireless power and data transmission AC to DC converter for an implantable device.

    Liu, Jhao-Yan; Tang, Kea-Tiong

    2013-01-01

    This article presents a novel AC to DC converter implemented by standard CMOS technology, applied for wireless power transmission. This circuit combines the functions of the rectifier and DC to DC converter, rather than using the rectifier to convert AC to DC and then supplying the required voltage with regulator as in the transitional method. This modification can reduce the power consumption and the area of the circuit. This circuit also transfers the loading condition back to the external circuit by the load shift keying(LSK), determining if the input power is not enough or excessive, which increases the efficiency of the total system. The AC to DC converter is fabricated with the TSMC 90nm CMOS process. The circuit area is 0.071mm(2). The circuit can produce a 1V DC voltage with maximum output current of 10mA from an AC input ranging from 1.5V to 2V, at 1MHz to 10MHz. PMID:24110077

  14. HST/ACS Direct Ages of the Dwarf Elliptical Galaxies NGC 147 and NGC 185

    Geha, M; Grocholski, A; Dolphin, A; van der Marel, R P; Guhathakurta, P

    2015-01-01

    We present the deepest optical photometry for any dwarf elliptical (dE) galaxy based on Hubble Space Telescope ACS observations of the Local Group dE galaxies NGC 147 and NGC 185. The resulting F606W and F814W color-magnitude diagrams are the first to reach below the main sequence turnoff in a dE galaxy, allowing us to determine full star formation histories in these systems. The ACS fields are located ~1.5 effective radii from the galaxy center to avoid photometric crowding. While our ACS pointings in both dEs show unambiguous evidence for old and intermediate age stars, the mean age in NGC 147 is ~ 4 Gyr younger as compared to NGC 185. In NGC 147, only 40% of stars were in place 12.5 Gyrs ago (z~5), with the bulk of the remaining stellar population forming between 5 to 7 Gyr. In contrast, 70% of stars were formed in NGC 185 field more than12.5 Gyr ago with the majority of the remaining population forming between 8 to 10 Gyr. Star formation ceased in both ACS fields at least 3 Gyr ago. Previous observations ...

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

    2013-07-01

    ... will transfer to AWN all remaining tangible and intangible assets owned, leased or held by ACS Wireless.... \\6\\ ACS Group will cause certain of its other subsidiaries to transfer wireless spectrum licenses and...'' as the power to exercise a controlling influence over the management or policies of a company,...

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

    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…

  17. Search for β-delayed fission of 228Ac

    Radium was radiochemically separated from natural thorium. Thin 228Ra→β-228Ac sources were prepared and exposed to mica fission track detectors, and measured by an HPGe γ-ray detector. The β-delayed fission events of 228Ac were observed and its β-delayed fission probability was found to be (5±2)x10-12

  18. Improved Design Methods for Robust Single- and Three-Phase ac-dc-ac Power Converters

    Qin, Zian

    proposed new active power decoupling method, the ripple power in the converter can be compensated in a more efficient and more compact way. Then, Chapter 5 changes the scope of the thesis to three-phase converters, and the nine-switch converter, as a reduced switch version of two three-phase full......-bridges connected back-to-back, is studied. Application criteria of the nine-switch converter are investigated for reducing the relatively high stress introduced by the less number of switches. In Chapter 6 a rotating speed controller design method is proposed for improving the thermal loading of the three...... to users. Their performances including cost, efficiency, reliability, and so on, therefore are more important concerns than they were. The objective of this thesis is to study and propose advanced design methods for robust ac-dc-ac converters, which are widely used interfaces in energy conversion...

  19. Lagrangian structures, integrability and chaos for 3D dynamical equations 45.20.Jj Lagrangian and Hamiltonian mechanics; 02.30.Ik Integrable systems; 05.45.Ac Low-dimensional chaos;

    Bustamante, M D

    2003-01-01

    In this paper, we consider the general setting for constructing action principles for three-dimensional first-order autonomous equations. We present the results for some integrable and non-integrable cases of the Lotka-Volterra equation, and show Lagrangian descriptions which are valid for systems satisfying Shil'nikov criteria on the existence of strange attractors, though chaotic behaviour has not been verified up to now. The Euler-Lagrange equations we get for these systems usually present 'time reparametrization' invariance, though other kinds of invariance may be found according to the kernel of the associated symplectic 2-form. The formulation of a Hamiltonian structure (Poisson brackets and Hamiltonians) for these systems from the Lagrangian viewpoint leads to a method of finding new constants of the motion starting from known ones, which is applied to some systems found in the literature known to possess a constant of the motion, to find the other and thus showing their integrability. In particular, w...

  20. 40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

    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...