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Sample records for ac power regulator

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

    NASA Technical Reports Server (NTRS)

    Reitan, D. K.

    1973-01-01

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

  2. AC Optimal Power Flow

    SciTech Connect

    2016-10-04

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

  3. AC power system breadboard

    NASA Technical Reports Server (NTRS)

    Wappes, Loran J.; Sundberg, R.; Mildice, J.; Peterson, D.; Hushing, S.

    1987-01-01

    The object of this program was to design, build, test, and deliver a high-frequency (20-kHz) Power System Breadboard which would electrically approximate a pair of dual redundant power channels of an IOC Space Station. This report describes that program, including the technical background, and discusses the results, showing that the major assumptions about the characteristics of this class of hardware (size, mass, efficiency, control, etc.) were substantially correct. This testbed equipment has been completed and delivered to LeRC, where it is operating as a part of the Space Station Power System Test Facility.

  4. Simultaneous distribution of AC and DC power

    DOEpatents

    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.

  5. Phase protection system for ac power lines

    NASA Technical Reports Server (NTRS)

    Wong, W. J. (Inventor)

    1974-01-01

    The system described provides protection for phase sensitive loads from being or remaining connected to ac power lines whenever a phase reversal occurs. It comprises a solid state phase detection circuit, a dc power relay circuit, an ac-to-dc converter for energizing the relay circuit, and a bistable four terminal transducer coupled between the phase detection circuit and the power relay circuit, for controlling both circuits.

  6. Resistojet control and power for high frequency ac buses

    NASA Technical Reports Server (NTRS)

    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.

  7. 21 CFR 886.1630 - AC-powered photostimulator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  8. 21 CFR 886.1630 - AC-powered photostimulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered photostimulator. 886.1630 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1630 AC-powered photostimulator. (a) Identification. An AC-powered photostimulator is an AC-powered device intended to provide light stimulus...

  9. 21 CFR 886.1850 - AC-powered slitlamp biomicroscope.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  10. 21 CFR 886.1850 - AC-powered slitlamp biomicroscope.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered slitlamp biomicroscope. 886.1850... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1850 AC-powered slitlamp biomicroscope. (a) Identification. An AC-powered slitlamp biomicroscope is an AC-powered device that is...

  11. 21 CFR 888.1240 - AC-powered dynamometer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered dynamometer. 888.1240 Section 888.1240...) MEDICAL DEVICES ORTHOPEDIC DEVICES Diagnostic Devices § 888.1240 AC-powered dynamometer. (a) Identification. An AC-powered dynamometer is an AC-powered device intended for medical purposes to...

  12. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  13. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  14. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  15. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  16. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  17. 21 CFR 888.1240 - AC-powered dynamometer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  18. The ac power system testbed

    NASA Technical Reports Server (NTRS)

    Mildice, J.; Sundberg, R.

    1987-01-01

    The object of this program was to design, build, test, and deliver a high frequency (20 kHz) Power System Testbed which would electrically approximate a single, separable power channel of an IOC Space Station. That program is described, including the technical background, and the results are discussed showing that the major assumptions about the characteristics of this class of hardware (size, mass, efficiency, control, etc.) were substantially correct. This testbed equipment was completed and delivered and is being operated as part of the Space Station Power System Test Facility.

  19. Power control for ac motor

    NASA Technical Reports Server (NTRS)

    Dabney, R. W. (Inventor)

    1984-01-01

    A motor controller employing a triac through which power is supplied to a motor is described. The open circuit voltage appearing across the triac controls the operation of a timing circuit. This timing circuit triggers on the triac at a time following turn off which varies inversely as a function of the amplitude of the open circuit voltage of the triac.

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

    SciTech Connect

    Battle, R E; Campbell, D J

    1983-07-01

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

  1. AC power generation from microbial fuel cells

    NASA Astrophysics Data System (ADS)

    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.

  2. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered patient lift. 880.5500 Section 880.5500 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an...

  3. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic 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...

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

    NASA Technical Reports Server (NTRS)

    1972-01-01

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

  5. Programmable AC power supply for simulating power transient expected in fusion reactor

    SciTech Connect

    Halimi, B.; Suh, K. Y.

    2012-07-01

    This paper focus on control engineering of the programmable AC power source which has capability to simulate power transient expected in fusion reactor. To generate the programmable power source, AC-AC power electronics converter is adopted to control the power of a set of heaters to represent the transient phenomena of heat exchangers or heat sources of a fusion reactor. The International Thermonuclear Experimental Reactor (ITER) plasma operation scenario is used as the basic reference for producing this transient power source. (authors)

  6. ac Magnetization transport and power absorption in nonitinerant spin chains.

    PubMed

    Trauzettel, Björn; Simon, Pascal; Loss, Daniel

    2008-07-04

    We investigate the ac transport of magnetization in nonitinerant quantum systems such as spin chains described by the XXZ Hamiltonian. Using linear response theory, we calculate the ac magnetization current and the power absorption of such magnetic systems. Remarkably, the difference in the exchange interaction of the spin chain itself and the bulk magnets (i.e., the magnetization reservoirs), to which the spin chain is coupled, strongly influences the absorbed power of the system. This feature can be used in future spintronic devices to control power dissipation. Our analysis allows us to make quantitative predictions about the power absorption, and we show that magnetic systems are superior to their electronic counterparts.

  7. Nonlinear modal interaction in HVDC/AC power systems with dc power modulation

    SciTech Connect

    Ni, Y.X.; Vittal, V.; Kliemann, W.; Fouad, A.A.

    1996-11-01

    In this paper investigation of nonlinear modal interaction using the normal form of vector fields technique is extended to HVDC/AC power systems with dc power modulation. The ac-dc interface equations are solved to form a state space model with second order approximation. Using the normal form technique, the system`s nonlinear dynamic characteristics are obtained. The proposed approach is applied to a 4-generator HVDC/AC test power system, and compare with the time domain solution.

  8. 21 CFR 880.6320 - AC-powered medical examination light.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  9. 21 CFR 880.6320 - AC-powered medical examination light.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered medical examination light. 880.6320... Miscellaneous Devices § 880.6320 AC-powered medical examination light. (a) Identification. An AC-powered medical examination light is an AC-powered device intended for medical purposes that is used to illuminate...

  10. Lightweight Regulated Power Supply

    NASA Technical Reports Server (NTRS)

    Mclyman, C. W.

    1985-01-01

    Power-supply circuit regulates output voltage by adjusting frequency of chopper circuit according to variations. Currently installed in battery charger for electric wheelchair, circuit is well suited to other uses in which light weight is important - for example, in portable computers, radios, and test instruments.

  11. Topologically protected loop flows in high voltage AC power grids

    NASA Astrophysics Data System (ADS)

    Coletta, T.; Delabays, R.; Adagideli, I.; Jacquod, Ph

    2016-10-01

    Geographical features such as mountain ranges or big lakes and inland seas often result in large closed loops in high voltage AC power grids. Sizable circulating power flows have been recorded around such loops, which take up transmission line capacity and dissipate but do not deliver electric power. Power flows in high voltage AC transmission grids are dominantly governed by voltage angle differences between connected buses, much in the same way as Josephson currents depend on phase differences between tunnel-coupled superconductors. From this previously overlooked similarity we argue here that circulating power flows in AC power grids are analogous to supercurrents flowing in superconducting rings and in rings of Josephson junctions. We investigate how circulating power flows can be created and how they behave in the presence of ohmic dissipation. We show how changing operating conditions may generate them, how significantly more power is ohmically dissipated in their presence and how they are topologically protected, even in the presence of dissipation, so that they persist when operating conditions are returned to their original values. We identify three mechanisms for creating circulating power flows, (i) by loss of stability of the equilibrium state carrying no circulating loop flow, (ii) by tripping of a line traversing a large loop in the network and (iii) by reclosing a loop that tripped or was open earlier. Because voltages are uniquely defined, circulating power flows can take on only discrete values, much in the same way as circulation around vortices is quantized in superfluids.

  12. Introducing AC inductive reactance with a power tool

    NASA Astrophysics Data System (ADS)

    Bryant, Wesley; Baker, Blane

    2016-09-01

    The concept of reactance in AC electrical circuits is often non-intuitive and difficult for students to grasp. In order to address this lack of conceptual understanding, classroom exercises compare the predicted resistance of a power tool, based on electrical specifications, to measured resistance. Once students discover that measured resistance is smaller than expected, they are asked to explain these observations using previously studied principles of magnetic induction. Exercises also introduce the notion of inductive reactance and impedance in AC circuits and, ultimately, determine self-inductance of the motor windings within the power tool.

  13. Watts Up? Pro AC Power Meter for Automated Energy Recording

    PubMed Central

    Hirst, Jason M.; Miller, Jonathan R.; Kaplan, Brent A.; Reed, Derek D.

    2013-01-01

    The purpose of the present paper is to review the Watts up? Pro AC power meter. Evaluations of the meter's reliability for measuring energy consumption by consumer electronics yielded acceptable levels of reliability. Implications and limitations for the use of this product in behavior analytic research and practice are discussed.

  14. Introducing AC Inductive Reactance with a Power Tool

    ERIC Educational Resources Information Center

    Bryant, Wesley; Baker, Blane

    2016-01-01

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

  15. ac power control in the Core Flow Test Loop

    SciTech Connect

    McDonald, D.W.

    1980-01-01

    This work represents a status report on a development effort to design an ac power controller for the Core Flow Test Loop. The Core Flow Test Loop will be an engineering test facility which will simulate the thermal environment of a gas-cooled fast-breeder reactor. The problems and limitations of using sinusoidal ac power to simulate the power generated within a nuclear reactor are addressed. The transformer-thyristor configuration chosen for the Core Flow Test Loop power supply is presented. The initial considerations, design, and analysis of a closed-loop controller prototype are detailed. The design is then analyzed for improved performance possibilities and failure modes are investigated at length. A summary of the work completed to date and a proposed outline for continued development completes the report.

  16. Photovoltaic Inverter Controllers Seeking AC Optimal Power Flow Solutions

    SciTech Connect

    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.

  17. Development of a uninterrupted power system: ac and dc to dc converter

    NASA Technical Reports Server (NTRS)

    Cronin, D. L.; Schoenfeld, A. D.

    1973-01-01

    This program covered the design, fabrication and testing of an advanced development model uninterrupted power system. The input and output requirements imposed on the power processor were specified such that the unit is electrically interchangeable with existing power systems used by the Federal Aviation Administration in installations which have a history of failure due to electrical transient conditions. Input power is from either of two single-phase ac power sources or batteries with electronic selection and transfer between power sources. Battery reconditioning is automatic when either ac source is present. The output power is rated at 84OW; the nominal output is 24V at 35A. Within the 84OW limit, the regulated output voltage is adjustable from 22V to 30Vdc. Protection against continuous overloading or short circuit is provided. The unit is packaged in a standard 19-inch rack mount configuration with 7-inch panel height. Controls are on the front panel with power input and output through connectors on the rear surface. Cooling is by free convection from fin areas located on the side and rear panels. The packaged unit weighs 52.8 lbs., which can be reduced significantly if a three-phase ac power source is used.

  18. UPS with input commutation between ac and dc sources of power

    SciTech Connect

    Severinsky, A.J.

    1993-08-31

    An uninterruptible power supply is described, said power supply comprising: AC input terminal means for receiving a first AC voltage from an AC power source; DC input terminal means for receiving a first DC voltage from a DC power source; AC output terminal means for connecting to a load; converter means for converting said first AC voltage to a second DC voltage across electrical charge storage means coupled to said converter means, said second DC voltage being larger than the maximum peak voltage of said first AC voltage and said first DC voltage; switching means coupled to said AC power source and said DC power source for selectively connecting said AC power source or said DC power source to said converter means; inverter means coupled to said electrical charge storage means for receiving said second DC voltage and inverting said second DC voltage to a second AC voltage, said second AC voltage being coupled to said AC output terminal means; and control means coupled to said switching means for controlling the operation of said switching means, said control means operating said switching means to connect said AC power source to said converter means only when said first AC voltage is within a predetermined range and operating to connect said DC power source to said converter means when said first AC voltage is outside of said range.

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

    NASA Astrophysics Data System (ADS)

    Basu, Kaushik

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

  20. Development of an analytical tool to study power quality of AC power systems for large spacecraft

    NASA Technical Reports Server (NTRS)

    Kraft, L. Alan; Kankam, M. David

    1991-01-01

    A harmonic power flow program applicable to space power systems with sources of harmonic distortion is described. The algorithm is a modification of the Electric Power Research Institute's HARMFLO program which assumes a three phase, balanced, AC system with loads of harmonic distortion. The modified power flow program can be used with single phase, AC systems. Early results indicate that the required modifications and the models developed are quite adequate for the analysis of a 20 kHz testbed built by General Dynamics Corporation. This is demonstrated by the acceptable correlation of present results with published data. Although the results are not exact, the discrepancies are relatively small.

  1. Development of an analytical tool to study power quality of ac power systems for large spacecraft

    NASA Technical Reports Server (NTRS)

    Kraft, L. A.; Kankam, M. D.

    1991-01-01

    A harmonic power flow program applicable to space power systems with sources of harmonic distortion is described. The algorithm is a modification of Electric Power Research Institute's HARMFLO program which assumes a three-phase, balanced, ac system with loads of harmonic distortion. The modified power flow program can be used with single phase, ac systems. Early results indicate that the required modifications and the models developed are quite adequate for the analysis of a 20-kHz testbed built by General Dynamics Corporation. This is demonstrated by the acceptable correlation of the present results with published data. Although the results are not exact, the discrepancies are relatively small.

  2. Comprehensive review of high power factor ac-dc boost converters for PFC applications

    NASA Astrophysics Data System (ADS)

    De Castro Pereira, Dênis; Da Silva, Márcio Renato; Mateus Silva, Elder; Lessa Tofoli, Fernando

    2015-08-01

    High power factor rectifiers have been consolidated as an effective solution to improve power quality indices in terms of input power factor correction, reduction in the total harmonic distortion of the input current and also regulated dc voltages. Within this context, this subject has motivated the introduction of numerous converter topologies based on classic dc-dc structures associated with novel control techniques, thus leading to the manufacturing of dedicated integrated circuits that allow high input power factor by adding a front-end stage to switch-mode converters. In particular, boost converters in continuous current mode (CCM) are widely employed since they allow obtaining minimised electromagnetic interference levels. This work is concerned with a literature review involving relevant ac-dc single-phase boost-based topologies with high input power factor. The evolution of aspects regarding the conventional boost converter is shown in terms of improved characteristics inherent to other ac-dc boost converters. Additionally, the work intends to be a fast and concise reference to single-phase ac-dc boost converters operating in CCM for engineers, researchers and experts in the field of power electronics by properly analysing and comparing the aforementioned rectifiers.

  3. A novel wireless power and data transmission AC to DC converter for an implantable device.

    PubMed

    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.

  4. Resonant AC power system proof-of-concept test program

    NASA Technical Reports Server (NTRS)

    Wappes, Loran J.

    1986-01-01

    Proof-of-concept testing was performed on a 20-kHz, resonant power system breadboard from 1981 through 1985. The testing began with the evaluation of a single, 1.0-kW resonant inverter and progressed to the testing of breadboard systems with higher power levels and more capability. The final breadboard configuration tested was a 25.0-kW breadboard with six inverters providing power to three user-interface modules over a 50-meter, 20-kHz bus. The breadboard demonstrated the ability to synchronize multiple resonant inverters to power a common bus. Single-phase and three-phase 20-kHz power distribution was demonstrated. Simple conversion of 20-kHz to dc and variable-frequency ac was demonstrated as was bidirectional power flow between 20-kHz and dc. Steady state measurements of efficiency, power-factor tolerance, and conducted emissions and conducted susceptibility were made. In addition, transient responses were recorded for such conditions as start up, shut down, load changes. The results showed the 20-kHz resonant system to be a desirable technology for a spacecraft power management and distribution system with multiple users and a utility-type bus.

  5. Apple MdACS6 Regulates Ethylene Biosynthesis During Fruit Development Involving Ethylene-Responsive Factor.

    PubMed

    Li, Tong; Tan, Dongmei; Liu, Zhi; Jiang, Zhongyu; Wei, Yun; Zhang, Lichao; Li, Xinyue; Yuan, Hui; Wang, Aide

    2015-10-01

    Ethylene biosynthesis in plants involves different 1-aminocyclopropane-1-carboxylic acid synthase (ACS) genes. The regulation of each ACS gene during fruit development is unclear. Here, we characterized another apple (Malus×domestica) ACS gene, MdACS6. The transcript of MdACS6 was observed not only in fruits but also in other tissues. During fruit development, MdACS6 was initiated at a much earlier stage, whereas MdACS3a and MdACS1 began to be expressed at 35 d before harvest and immediateley after harvest, respectively. Moreover, the enzyme activity of MdACS6 was significantly lower than that of MdACS3a and MdACS1, accounting for the low ethylene biosynthesis in young fruits. Overexpression of MdACS6 (MdACS6-OE) by transient assay in apple showed enhanced ethylene production, and MdACS3a was induced in MdACS6-OE fruits but not in control fruits. In MdACS6 apple fruits silenced by the virus-induced gene silencing (VIGS) system (MdACS6-AN), neither ethylene production nor MdACS3a transcript was detectable. In order to explore the mechanism through which MdACS3a was induced in MdACS6-OE fruits, we investigated the expression of apple ethylene-responsive factor (ERF) genes. The results showed that the expression of MdERF2 was induced in MdACS6-OE fruits and inhibited in MdACS6-AN fruits. Yeast one-hybrid assay showed that MdERF2 protein could bind to the promoter of MdACS3a. Moreover, down-regulation of MdERF2 in apple flesh callus led to a decrease of MdACS3a expression, demonstrating the regulation of MdERF2 on MdACS3a. The mechanism through which MdACS6 regulates the action of MdACS3a was discussed.

  6. Electrical Model of Balanced AC HTS Power Cable

    NASA Astrophysics Data System (ADS)

    Zuijderduin, R.; Chevtchenko, O.; Smit, J. J.; Willén, D.; Melnik, I.; Geschiere, A.

    The future electricity grid will be more sustainable and it will have more power transmission and distribution capability with more electrical power added from decentralized sources on distribution level and from wind parks and other large sources on transmission level. More interconnections and more underground transmission and distribution will be put up. Use of high temperature superconducting (HTS) power cables provides solutions to many of the future grid problems caused by these trends. In this paper we present an electrical model of a balanced 6 km-long three phase triaxial HTS power cable for the Dutch project being developed by a consortium of Alliander, Ultera™ and TUD. The cable currents in all three phases are balanced by selecting proper twist pitches and insulation thickness. The paper focuses on determining inductances, capacitances and AC losses of the balanced cable. Using the developed model, we also determine the voltage drop as function of the cable length, the neutral current and the effect of the imbalanced capacitances on the current distribution of the Dutch distribution cable. The model is validated and it can be used for accurate simulation of the electrical behaviour of triaxial HTS cables in electrical grids.

  7. 21 CFR 880.5510 - Non-AC-powered patient lift.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Non-AC-powered patient lift. 880.5510 Section 880... Devices § 880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a... patient in the horizontal or other required position from one place to another, as from a bed to a...

  8. Photovoltaic power regulation system

    SciTech Connect

    Jaster, D.R.

    1986-02-18

    This patent describes a multi-solar module direct current battery charging arrangement consisting of: a group of solar cells; a reverse current blocking diode; a first relay having an energizing winding; and a set of contacts; the diode, the energizing winding and the solar module connected across the battery; a second relay having a second set of contacts; the first relay contacts operate upon a predetermined current flow through the first relay winding to close the first relay and contacts to operate the second relay. A voltage regulator has a set of contacts. The regulator contacts operate upon the battery reaching a predetermined state of charge as indicated by the voltage level; solar cells and a third relay having a set of contacts; the second relay make contacts, the voltage regulator make contacts, the third relay and the second group of solar cells connected in series; the third relay operated upon the second relay operating indicating the solar cells are functioning, and the voltage regulator operating its associated contacts indicating the batteries require further charging to operate the third relay; and the third relay operated to close the associated contacts to connect the second plurality of solar cells across the battery.

  9. Power-law resistivity, magnetic relaxation and ac susceptibility

    SciTech Connect

    Gilchrist, J.; van der Beek, C.J.

    1994-07-01

    The nonlinear diffusion of magnetic flux into a superconducting sample can be studied by measuring the relaxation of the magnetisation after application of a step field or by measuring the ac susceptibility, {chi}{sub 1} and its third harmonic, {chi}{sub 3}, or preferably both methods covering different time scales. Each has been analysed recently for a field-cooled sample of a material whose creep activation energy depends logarithmically on current density, J corresponding to a power-law relation between electric field, E and J. Here, results are compared, using a universal scaling depth. Maximum {chi}{sub 1}{double_prime} {vert_bar}{chi}{sub 3}{vert_bar} and values occur, and also the magnetisation has relaxed to half its initial value when the scaling depth is comparable to the sample half-thickness.

  10. Shunt regulation electric power system

    NASA Technical Reports Server (NTRS)

    Wright, W. H.; Bless, J. J. (Inventor)

    1971-01-01

    A regulated electric power system having load and return bus lines is described. A plurality of solar cells interconnected in a power supplying relationship and having a power shunt tap point electrically spaced from the bus lines is provided. A power dissipator is connected to the shunt tap point and provides for a controllable dissipation of excess energy supplied by the solar cells. A dissipation driver is coupled to the power dissipator and controls its conductance and dissipation and is also connected to the solar cells in a power taping relationship to derive operating power therefrom. An error signal generator is coupled to the load bus and to a reference signal generator to provide an error output signal which is representative of the difference between the electric parameters existing at the load bus and the reference signal generator. An error amplifier is coupled to the error signal generator and the dissipation driver to provide the driver with controlling signals.

  11. The Single-phase AC Regulator on Base of Bidirectional IGBT Switches

    NASA Astrophysics Data System (ADS)

    Cimanis, Vladimirs; Hramcovs, Vladimirs; Rankis, Ivars

    2010-01-01

    In the work one of the methods for regulation of sinus shape AC voltage for middle-power loads with activeinductive character is observed. Such a regulator keeping output voltage of sinus shape must be fast-reacting and work in closed-loop system. It's shown, that for providing such features Buck and Boost pulse regulators can be applied. The only difference from DC pulse converters is that electronic switches in the system must be with bidirectional conductivity. For this reason an IGBT transistors can be applied with implemented in structure reverse diodes and if such two transistors are connected in series and with contrary conductivity then at activating both one of them will be in on-state. Realization of AC regulators with such switches is described in the work. Results of computer modeling also are given. Output voltage ripples are investigated on subject of their range and efficiency of filtering equipment on LC base. Such regulators can be applied for instance in electrical transport self supply systems.

  12. Power Quality Improvement in Bridgeless Ac-Dc Converter Based Multi-output Switched Mode Power Supply

    NASA Astrophysics Data System (ADS)

    Singh, Shihka; Singh, Bhim; Bhuvaneswari, G.; Bist, Vashist

    2014-12-01

    Computer power supplies are required to have multiple isolated regulated dc voltages with low ripple content and high input power factor at the utility interface. A dc-dc converter is used for obtaining these isolated multi-output dc voltages with excellent regulation. In this paper, a non-isolated ac-dc converter is proposed as the first stage converter to obtain a regulated dc output rather than using a simple uncontrolled diode bridge rectifier at the front end. A dc-dc converter is used at the second stage that has a high frequency transformer with multiple secondary windings to obtain different dc voltage levels at the output. The proposed bridgeless converter based power supply is designed using fundamental design equations, and different component values are calculated. Extensive simulations are carried out to demonstrate the improved performance of the proposed bridgeless converter based multi-output computer power supply at varying source voltages and load conditions. Experimental validation of the power supply is carried on a developed hardware prototype, and the test results are compared with the simulated performance for design verification.

  13. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered adjustable hospital bed. 880.5100 Section 880.5100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An...

  14. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered adjustable hospital bed. 880.5100 Section 880.5100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An...

  15. Alternative promoters regulate transcription of the gene that encodes stem cell surface protein AC133.

    PubMed

    Shmelkov, Sergey V; Jun, Lin; St Clair, Ryan; McGarrigle, Deirdre; Derderian, Christopher A; Usenko, Jaroslav K; Costa, Carla; Zhang, Fan; Guo, Xinzheng; Rafii, Shahin

    2004-03-15

    AC133 is a member of a novel family of cell surface proteins with 5 transmembrane domains. The function of AC133 is unknown. Although AC133 mRNA is detected in different tissues, its expression in the hematopoietic system is restricted to CD34+ stem cells. AC133 is also expressed on stem cells of other tissues, including endothelial progenitor cells. However, despite the potential importance of AC133 to the field of stem cell biology, nothing is known about the transcriptional regulation of AC133 expression. In this report we showed that the human AC133 gene has at least 9 distinctive 5'-untranslated region (UTR) exons, resulting in the formation of at least 7 alternatively spliced 5'-UTR isoforms of AC133 mRNA, which are expressed in a tissue-dependent manner. We found that transcription of these AC133 isoforms is controlled by 5 alternative promoters, and we demonstrated their activity on AC133-expressing cell lines using a luciferase reporter system. We also showed that in vitro methylation of 2 of these AC133 promoters completely suppresses their activity, suggesting that methylation plays a role in their regulation. Identification of tissue-specific AC133 promoters may provide a novel method to isolate tissue-specific stem and progenitor cells.

  16. The thermoelectric power of Al-0.99 wt.% Fe alloys in the AC magnetic field

    NASA Astrophysics Data System (ADS)

    Lan, Qing; Zhang, Jianfeng; Liu, Xuan; Le, Qichi; Yin, Siqi; Liu, Yiting; Cui, Jianzhong

    2017-04-01

    The melt structure of Al-0.99 wt.% Fe alloys in the AC magnetic field have been studied with thermoelectric power by the four-point probe technique and microstructure with the liquid quenching method. The melt temperature is in the range of 913 K–1013 K. The thermoelectric power increases due to the AC magnetic field and decreases after the AC magnetic field stops, then keeps stable. Some characteristic parameters of thermoelectric power in the recovery process are used to represent the variation of melt structure. The α-Al phase refinement in the AC magnetic field is attributed to the persistent variation of melt structure. The persistent variation of thermoelectric power can be used to characterize the variation of the α-Al phase size. The hardness increases and the diffraction peaks of some planes reduce, which can reflect the uniform and disorder melt structure in the AC magnetic field.

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

    PubMed

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

    2014-12-10

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

  18. An AC motor drive with power factor control for low cost applications

    NASA Astrophysics Data System (ADS)

    Bellar, Maria Dias

    2000-10-01

    The front-end rectifier followed by a pulse-width modulated voltage source inverter (PWM-VSI) has been a well-established power converter configuration for many industrial drives. The increasing costs on the utility usage, due to power quality regulations, and the need to improve the VA capacity of systems, e.g. off-shore drilling rigs, have increased the interest in the development of power electronic equipment with power factor control capability. Electrical motors consume a large amount of the available electrical energy, and this energy tends to increase due to the massive emerging applications of electrical motor drives in appliances and in industrial processes. Therefore, the improvement of the power factor of these low power drive systems, usually in the range from fractional horse-power (hp) to 1 hp, is of particular interest. For these power ratings, the system configuration usually comprises a single-phase to three-phase type of converter with additional circuitry for power factor control (PFC). However, this approach has an impact on the system cost and packaging. In this work, a new concept of integrating motor and power factor controls by using a single-phase to three-phase DSP based six-switch converter topology is presented. Unlike other configurations using extra switch(es) and/or extra boost inductor, in this circuit the boost action, for input current shaping, is done by the motor leakage inductances. The power factor control and inverter operation are performed by applying two modulating signals to the SPWM control logic of the converter. In this dissertation, the converter operation and a proposed control strategy will be explained. Simulation and experimental results for a DSP based induction motor drive will be provided as proof of concept. The feasibility and potential of this configuration for ac motor drive applications will be established. The impact of this scheme on the machine operation will also be discussed.

  19. AcSDKP Regulates Cell Proliferation through the PI3KCA/Akt Signaling Pathway

    PubMed Central

    Hu, Ping; Li, Bin; Zhang, Wenhua; Li, Yijian; Li, Guang; Jiang, Xinnong; Wdzieczak-Bakala, Joanna; Liu, Jianmiao

    2013-01-01

    The natural tetrapeptide acetyl-N-Ser-Asp-Lys-Pro (AcSDKP) is generated from the N-terminus of thymosin-β4 through enzymatic cleavage by prolyl oligopeptidase (POP). AcSDKP regulation of proliferation of different cells is implicated in hematopoiesis and angiogenesis. This tetrapeptide present in almost all cells was recently detected at elevated concentrations in neoplastic diseases. However, previously reported in vitro and in vivo studies indicate that AcSDKP does not contribute to the pathogenesis of cancers. Here we show that exogenous AcSDKP exerts no effect on the proliferation of actively dividing malignant cells. Using S17092, a specific POP inhibitor (POPi), to suppress the biosynthesis of AcSDKP in U87-MG glioblastoma cells characterized by high intracellular levels of this peptide, we found that all tested doses of POPi resulted in an equally effective depletion of AcSDKP, which was not correlated with the dose-dependent decreases in the proliferation rate of treated cells. Interestingly, addition of exogenous AcSDKP markedly reversed the reduction in the proliferation of U87-MG cells treated with the highest dose of POPi, and this effect was associated with activation of the phosphatidylinositol-3 kinase (PI3K)/Akt pathway. However, extracellular-regulated protein kinase (ERK) activation was unaltered by S17092 and AcSDKP co-treatment. Knockdown of individual PI3K catalytic subunits revealed that p110α and p110β contributed differently to AcSDKP regulation of U87-MG cell proliferation. Disruption of p110α expression by small interfering RNA (siRNA) abrogated AcSDKP-stimulated Akt phosphorylation, whereas knockdown of p110β expression exhibited no such effect. Our findings indicate for the first time that the PI3KCA/Akt pathway mediates AcSDKP regulation of cell proliferation and suggest a role for this ubiquitous intracellular peptide in cell survival. PMID:24244481

  20. Mathematical model for the power supply system of an autonomous object with an AC power transmission over a cable rope

    NASA Astrophysics Data System (ADS)

    Rulevskiy, V. M.; Bukreev, V. G.; Shandarova, E. B.; Kuleshova, E. O.; Shandarov, S. M.; Vasilyeva, Yu Z.

    2017-02-01

    A modeling problem of the power system, which provides an AC power transmission to a submersible device over the conducting rope, was considered. The power supply system units and their parameters are described. The system multi-dimensional mathematical model in the variables state space with regard to the nonlinear characteristic of system elements is proposed.

  1. Voltage source ac-to-dc converters for high-power transmitters

    NASA Technical Reports Server (NTRS)

    Cormier, R.

    1990-01-01

    This work was done to optimize the design of the components used for the beam power supply, which is a component of the transmitters in the Deep Space Network (DSN). The major findings are: (1) the difference in regulation between a six-pulse and a twelve-pulse converter is at most 7 percent worse for the twelve-pulse converter; (2) the commutation overlap angle of a current source converter equals that of a voltage source converter with continuous line currents; (3) the sources of uncharacteristic harmonics are identified with SPICE simulation; (4) the use of an imperfect phase-shifting transformer for the twelve-pulse converter generates a harmonic at six times the line frequency; and (5) the assumptions usually made in analyzing converters can be relaxed with SPICE simulation. The results demonstrate the suitability of using SPICE simulation to obtain detailed performance predictions of ac-to-dc converters.

  2. pH sensing via bicarbonate-regulated “soluble” adenylyl cyclase (sAC)

    PubMed Central

    Rahman, Nawreen; Buck, Jochen; Levin, Lonny R.

    2013-01-01

    Soluble adenylyl cyclase (sAC) is a source of the second messenger cyclic adenosine 3′, 5′ monophosphate (cAMP). sAC is directly regulated by bicarbonate (HCO−3) ions. In living cells, HCO−3 ions are in nearly instantaneous equilibrium with carbon dioxide (CO2) and pH due to the ubiquitous presence of carbonic anhydrases. Numerous biological processes are regulated by CO2, HCO−3, and/or pH, and in a number of these, sAC has been shown to function as a physiological CO2/HCO3/pH sensor. In this review, we detail the known pH sensing functions of sAC, and we discuss two highly-studied, pH-dependent pathways in which sAC might play a role. PMID:24324443

  3. Power factor control system for ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1981-01-01

    A power control circuit for an induction motor is disclosed in which a servo loop is used to control power input by controlling the power factor of motor operation. The power factor is measured by summing the voltage and current derived square wave signals.

  4. Motor power control circuit for ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1983-01-01

    A motor power control of the type which functions by controlling the power factor wherein one of the parameters of power factor current on time is determined by the on time of a triac through which current is supplied to the motor. By means of a positive feedback circuit, a wider range of control is effected.

  5. Development of software to improve AC power quality on large spacecraft

    NASA Technical Reports Server (NTRS)

    Kraft, L. Alan

    1991-01-01

    To insure the reliability of a 20 kHz, alternating current (AC) power system on spacecraft, it is essential to analyze its behavior under many adverse operating conditions. Some of these conditions include overloads, short circuits, switching surges, and harmonic distortions. Harmonic distortions can become a serious problem. It can cause malfunctions in equipment that the power system is supplying, and, during distortions such as voltage resonance, it can cause equipment and insulation failures due to the extreme peak voltages. To address the harmonic distortion issue, work was begun under the 1990 NASA-ASEE Summer Faculty Fellowship Program. Software, originally developed by EPRI, called HARMFLO, a power flow program capable of analyzing harmonic conditions on three phase, balanced, 60 Hz AC power systems, was modified to analyze single phase, 20 kHz, AC power systems. Since almost all of the equipment used on spacecraft power systems is electrically different from equipment used on terrestrial power systems, it was also necessary to develop mathematical models for the equipment to be used on the spacecraft. The modelling was also started under the same fellowship work period. Details of the modifications and models completed during the 1990 NASA-ASEE Summer Faculty Fellowship Program can be found in a project report. As a continuation of the work to develop a complete package necessary for the full analysis of spacecraft AC power system behavior, deployment work has continued through NASA Grant NAG3-1254. This report details the work covered by the above mentioned grant.

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

    NASA Technical Reports Server (NTRS)

    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.

  7. Unity power factor switching regulator

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E. (Inventor)

    1983-01-01

    A single or multiphase boost chopper regulator operating with unity power factor, for use such as to charge a battery is comprised of a power section for converting single or multiphase line energy into recharge energy including a rectifier (10), one inductor (L.sub.1) and one chopper (Q.sub.1) for each chopper phase for presenting a load (battery) with a current output, and duty cycle control means (16) for each chopper to control the average inductor current over each period of the chopper, and a sensing and control section including means (20) for sensing at least one load parameter, means (22) for producing a current command signal as a function of said parameter, means (26) for producing a feedback signal as a function of said current command signal and the average rectifier voltage output over each period of the chopper, means (28) for sensing current through said inductor, means (18) for comparing said feedback signal with said sensed current to produce, in response to a difference, a control signal applied to the duty cycle control means, whereby the average inductor current is proportionate to the average rectifier voltage output over each period of the chopper, and instantaneous line current is thereby maintained proportionate to the instantaneous line voltage, thus achieving a unity power factor. The boost chopper is comprised of a plurality of converters connected in parallel and operated in staggered phase. For optimal harmonic suppression, the duty cycles of the switching converters are evenly spaced, and by negative coupling between pairs 180.degree. out-of-phase, peak currents through the switches can be reduced while reducing the inductor size and mass.

  8. Preliminary study of AC power feeders for AGS booster

    SciTech Connect

    Meth, M.

    1992-07-17

    It has been proposed that the AGS Heavy Ion/Proton Booster be excited directly from the electric power distribution system without intervening an energy storage buffer such as an MG set or a magnetic energy buffer. The average power requirement of the AGS Booster is less than many single-loads presently housed on the lab site. However, the power swing will be the largest single pulsating load on the lab site. The large power swings will impact on the power grid producing utility-line disturbances such as voltage fluctuations and harmonic generation. Thus, it is necessary to carefully evaluate the quality of the electric power system resulting from the interconnection, such that the utility system is not degraded either on the lab site or at LILCO's substation.

  9. Preliminary study of AC power feeders for AGS booster

    SciTech Connect

    Meth, M.

    1992-07-17

    It has been proposed that the AGS Heavy Ion/Proton Booster be excited directly from the electric power distribution system without intervening an energy storage buffer such as an MG set or a magnetic energy buffer. The average power requirement of the AGS Booster is less than many single-loads presently housed on the lab site. However, the power swing will be the largest single pulsating load on the lab site. The large power swings will impact on the power grid producing utility-line disturbances such as voltage fluctuations and harmonic generation. Thus, it is necessary to carefully evaluate the quality of the electric power system resulting from the interconnection, such that the utility system is not degraded either on the lab site or at LILCO`s substation.

  10. Location Dependence of a MEMS Electromagnetic Transducer with respect to an AC Power Source

    NASA Astrophysics Data System (ADS)

    Houlihan, Ruth; Olszewski, Oskar; Waldron, Finbarr; O'Neill, Mike; Mathewson, Alan; Jackson, Nathan

    2016-10-01

    A MEMS, silicon based device with a piezoelectric layer and an integrated magnet is presented for magnetic to electrical transduction. The cantilever structure can be configured either as an energy harvester to harvest power from an AC power line or as an AC current sensor. The positioning of the transducer with respect to the AC conductor is critical in both scenarios. For the energy scavenger, correct positioning is required to optimize the harvested power. For the current sensor, it is necessary to optimise the sensitivity of the sensor. This paper considers the effect of the relative position of the transducer with respect to the wire on the resulting electromagnetic forces and torques driving the device. It is shown here that the magnetic torque acting on a cantilever beam with an integrated magnet and in the vicinity of an alternating electromagnetic field is a very significant driver of the cantilever oscillations.

  11. A system for tranmitting low frequency analog signals over ac power lines

    DOEpatents

    Baker, S.P.; Durall, R.L.; Haynes, H.D.

    1987-07-30

    A system for transmitting low frequency analog signals over ac power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an ac power line. The modulation signal frequency range is selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the ac power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal. 4 figs.

  12. System for transmitting low frequency analog signals over AC power lines

    DOEpatents

    Baker, Steven P.; Durall, Robert L.; Haynes, Howard D.

    1989-01-01

    A system for transmitting low frequency analog signals over AC power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an AC power line. The modulation signal frequency range in selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the AC power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal.

  13. System for transmitting low frequency analog signals over AC power lines

    DOEpatents

    Baker, Steven P.; Durall, Robert L.; Haynes, Howard D.

    1989-09-05

    A system for transmitting low frequency analog signals over AC power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an AC power line. The modulation signal frequency range in selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the AC power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal.

  14. The power supply system model of the process submersible device with AC power transmission over the cable-rope

    NASA Astrophysics Data System (ADS)

    Rulevskiy, V. M.; Bukreev, V. G.; Kuleshova, E. O.; Shandarova, E. B.; Shandarov, S. M.; Vasilyeva, Yu Z.

    2017-02-01

    A practical problem of power supply system modeling for the process submersible device with AC power transmission over the cable-rope was considered. The problem is highly relevant in developing and operation of submersible centrifugal pumps and submersibles. The results of modeling a symmetrical three-phase power supply system and their compliance with the real data are given at the paper. The obtained results in the mathematical and simulation models were similar.

  15. AC Power Consumption of Single-Walled Carbon Nanotube Interconnects: Non-Equilibrium Green's Function Simulation

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takahiro; Sasaoka, Kenji; Watanabe, Satoshi

    2012-04-01

    We theoretically investigate the emittance and dynamic dissipation of a nanoscale interconnect consisting of a metallic single-walled carbon nanotube using the non-equilibrium Green's function technique for AC electronic transport. We show that the emittance and dynamic dissipation depend strongly on the contact conditions of the interconnect and that the power consumption can be reduced by adjusting the contact conditions. We propose an appropriate condition of contact that yields a high power factor and low apparent power.

  16. The ac power line protection for an IEEE 587 Class B environment

    NASA Technical Reports Server (NTRS)

    Roehr, W. D.; Clark, O. M.

    1984-01-01

    The 587B series of protectors are unique, low clamping voltage transient suppressors to protect ac-powered equipment from the 6000V peak open-circuit voltage and 3000A short circuit current as defined in IEEE standard 587 for Category B transients. The devices, which incorporate multiple-stage solid-state protector components, were specifically designed to operate under multiple exposures to maximum threat levels in this severe environment. The output voltage peaks are limited to 350V under maximum threat conditions for a 120V ac power line, thus providing adequate protection to vulnerable electronic equipment. The principle of operation and test performance data is discussed.

  17. Strengthening the SDP Relaxation of AC Power Flows with Convex Envelopes, Bound Tightening, and Valid Inequalities

    SciTech Connect

    Coffrin, Carleton James; Hijazi, Hassan L; Van Hentenryck, Pascal R

    2016-12-01

    Here this work revisits the Semidefine Programming (SDP) relaxation of the AC power flow equations in light of recent results illustrating the benefits of bounds propagation, valid inequalities, and the Convex Quadratic (QC) relaxation. By integrating all of these results into the SDP model a new hybrid relaxation is proposed, which combines the benefits from all of these recent works. This strengthened SDP formulation is evaluated on 71 AC Optimal Power Flow test cases from the NESTA archive and is shown to have an optimality gap of less than 1% on 63 cases. This new hybrid relaxation closes 50% of the open cases considered, leaving only 8 for future investigation.

  18. Non-oxidized porous silicon-based power AC switch peripheries

    NASA Astrophysics Data System (ADS)

    Menard, Samuel; Fèvre, Angélique; Valente, Damien; Billoué, Jérôme; Gautier, Gaël

    2012-10-01

    We present in this paper a novel application of porous silicon (PS) for low-power alternating current (AC) switches such as triode alternating current devices (TRIACs) frequently used to control small appliances (fridge, vacuum cleaner, washing machine, coffee makers, etc.). More precisely, it seems possible to benefit from the PS electrical insulation properties to ensure the OFF state of the device. Based on the technological aspects of the most commonly used AC switch peripheries physically responsible of the TRIAC blocking performances (leakage current and breakdown voltage), we suggest to isolate upper and lower junctions through the addition of a PS layer anodically etched from existing AC switch diffusion profiles. Then, we comment the voltage capability of practical samples emanating from the proposed architecture. Thanks to the characterization results of simple Al-PS-Si(P) structures, the experimental observations are interpreted, thus opening new outlooks in the field of AC switch peripheries.

  19. Development of software to improve AC power quality on large spacecraft

    NASA Technical Reports Server (NTRS)

    Kraft, L. Alan

    1991-01-01

    To insure the reliability of a 20 kHz, AC power system on spacecraft, it is essential to analyze its behavior under many adverse operating conditions. Some of these conditions include overloads, short circuits, switching surges, and harmonic distortions. Harmonic distortions can cause malfunctions in equipment that the power system is supplying, and during extreme distortions such as voltage resonance, it can cause equipment and insulation failures due to the extreme peak voltages. HARMFLO, a power flow computer program, which was capable of analyzing harmonic conditions on three phase, balanced, 60 Hz, AC power systems, was modified to analyze single phase, 20 kHz, AC power systems. Since almost all of the equipment used on spacecraft power systems is electrically different from equipment used on terrestrial power systems, it was also necessary to develop mathematical models for the equipment to be used on the spacecraft. The results are that (1) the harmonic power now has a model of a single phase, voltage controlled, full wave rectifier; and (2) HARMFLO was ported to the SUN workstation platform.

  20. AC losses in superconductors with a power-law constitutive relation

    NASA Astrophysics Data System (ADS)

    Agassi, Y. D.

    2015-10-01

    The observed constitutive relation between the electrical field and current density in cuprates high temperature superconductors is a power-law of the current. This functional dependence is presumably related to the giant flux-creep domain. It is shown that this constitutive relation reflects the statistical spread of the pinning potential associated with creep motion of vortex bundles. The AC losses emanating from a power-law constitutive relation are calculated in an approach focused on the superconductor's electric field. For a slab geometry in the presence of a parallel AC magnetic field or transport current, the calculated AC-loss scaling laws are consistent with BSCCO data and the critical state model. Extensions of the approach are briefly discussed.

  1. Power-supply regulation by microprocessor

    SciTech Connect

    Sheehan, J.; Langenbach, H.

    1983-01-01

    Many small-magnet power supplies are regulated by using a microprocessor system to generate control voltages to continuously servoregulate each power supply. The power supplies are of very simple design since all regulation and feedback hardware are parts of the microprocessor system. Most of the supplies are bipolar transistor followers, powered by a common unregulated dc power supply and are used to power trim steering magnets on the three NSLS synchrotron rings. Twelve-bit accuracy is obtained using commercially available microprocessor pc cards.

  2. 33. A.C. PANEL FOR MENTONE POWER HOUSE, P.L. & P. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. A.C. PANEL FOR MENTONE POWER HOUSE, P.L. & P. CO., LOS ANGELES. RETRACED FROM MASSON'S DRAWING NO. C-275. JAN. 20, 1909. SCE drawing no. 52880. - Santa Ana River Hydroelectric System, SAR-3 Powerhouse, San Bernardino National Forest, Redlands, San Bernardino County, CA

  3. Power-MOSFET Voltage Regulator

    NASA Technical Reports Server (NTRS)

    Miller, W. N.; Gray, O. E.

    1982-01-01

    Ninety-six parallel MOSFET devices with two-stage feedback circuit form a high-current dc voltage regulator that also acts as fully-on solid-state switch when fuel-cell out-put falls below regulated voltage. Ripple voltage is less than 20 mV, transient recovery time is less than 50 ms. Parallel MOSFET's act as high-current dc regulator and switch. Regulator can be used wherever large direct currents must be controlled. Can be applied to inverters, industrial furnaces photovoltaic solar generators, dc motors, and electric autos.

  4. Instantaneous characteristics simulation and analysis on three-level brushless AC synchronous generators of aeronautic constant speed and frequency AC power system

    NASA Astrophysics Data System (ADS)

    Ma, Xiaohe; Shen, Songhua

    2006-11-01

    This paper mainly introduces theoretical analysis and experimental results of instantaneous characteristics on a certain three level brushless three-phase AC synchronous generators. The analysis, modeling and simulations with Simplorer software of Ansoft Company are carried out. It establishes three level generator models, gives theoretical relation matrix equation, and simulates some instantaneous characteristics. Design of the system requires reliable simulation tools with comprehensive component libraries capable of dealing with complex system behavior. The simulation results verify that the proposed system model can efficiently simulate the instantaneous characteristics of the real AC generator system. It gives better design experiences and digital methods for aeronautic constant speed and frequency AC power system.

  5. Development of a 10 kW High Temperature High Power Density Three-Phase AC-DC-AC SiC Converter

    SciTech Connect

    Ning, Puqi

    2012-01-01

    This paper presents the development and experimental performance of a 10 kW, all SiC, 250 C junction temperature high-power-density three-phase ac-dc-ac converter. The electromagnetic interference filter, thermal system, high temperature package, and gate drive design are discussed in detail. Finally, tests confirming the feasibility and validating the theoretical basis of the prototype converter system are described.

  6. The Ethylene Biosynthesis Gene CitACS4 Regulates Monoecy/Andromonoecy in Watermelon (Citrullus lanatus)

    PubMed Central

    Manzano, Susana; Aguado, Encarnación; Martínez, Cecilia; Megías, Zoraida; García, Alicia; Jamilena, Manuel

    2016-01-01

    Monoecious and andromonoecious cultivars of watermelon are characterised by the production of male and female flower or male and hermaphrodite flowers, respectively. The segregation analysis in the offspring of crosses between monoecious and andromonoecious lines has demonstrated that this trait is controlled by a single gene pair, being the monoecious allele M semi-dominant to the andromonoecious allele A. The two studied F1 hybrids (MA) had a predominantly monoecious phenotype since both produced not only female flowers, but also bisexual flowers with incomplete stamens, and hermaphrodite flowers with pollen. Given that in other cucurbit species andromonoecy is conferred by mutations in the ethylene biosynthesis genes CmACS7, CsACS2 and CpACS27A we have cloned and characterised CitACS4, the watermelon gene showing the highest similarity with the formers. CitACS4 encoded for a type ACS type III enzyme that is predominantly expressed in pistillate flowers of watermelon. In the andromonoecious line we have detected a missense mutation in a very conserved residue of CitACS4 (C364W) that cosegregates with the andromonoecious phenotype in two independent F2 populations, concomitantly with a reduction in ethylene production in the floral buds that will develop as hermaphrodite flowers. The gene does not however co-segregates with other sex expression traits regulated by ethylene in this species, including pistillate flowering transition and the number of pistillate flowers per plant. These data indicate that CitAC4 is likely to be involved in the biosynthesis of the ethylene required for stamen arrest during the development of female flowers. The C364W mutation would reduce the production of ethylene in pistillate floral buds, promoting the conversion of female into hermaphrodite flowers, and therefore of monoecy into andromonoecy. PMID:27149159

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

    NASA Technical Reports Server (NTRS)

    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.

  8. A study of some features of ac and dc electric power systems for a space station

    NASA Technical Reports Server (NTRS)

    Hanania, J. I.

    1983-01-01

    This study analyzes certain selected topics in rival dc and high frequency ac electric power systems for a Space Station. The interaction between the Space Station and the plasma environment is analyzed, leading to a limit on the voltage for the solar array and a potential problem with resonance coupling at high frequencies. Certain problems are pointed out in the concept of a rotary transformer, and further development work is indicated in connection with dc circuit switching, special design of a transmission conductor for the ac system, and electric motors. The question of electric shock hazards, particularly at high frequency, is also explored. and a problem with reduced skin resistance and therefore increased hazard with high frequency ac is pointed out. The study concludes with a comparison of the main advantages and disadvantages of the two rival systems, and it is suggested that the choice between the two should be made after further studies and development work are completed.

  9. AC/DC Power Systems with Applications in Future Human Habitat on Lunar and Mars Bases

    NASA Astrophysics Data System (ADS)

    Chowdhury, Badrul H.; Hossain, Sabbir A.; Lawrence, James T.; Barave, Sushant

    2006-01-01

    As NASA readies itself for new space exploration initiatives starting with a human return to the Moon by the year 2020 eventually leading to human exploration of Mars, the requirements for a safe, efficient and comprehensive power system to support the exploration missions as well human habitat will become important issues to consider. Certain issues dealing with electric power generation and distribution on board Mars-bound vehicles and those on Lunar and Martian surfaces are described. The requirements for lightweight power generation dictates the use of a high frequency ac machine. Preliminary results of investigating the design of a permanent magnet synchronous machine is presented.

  10. Numerical modeling of MgB2 conductors for high power AC transmission

    NASA Astrophysics Data System (ADS)

    Grilli, F.; Chervyakov, A.; Zermeno, V.; Marian, A.; Grasso, G.; Goldacker, W.; Rubbia, C.

    2014-09-01

    Cables made of MgB2 superconductors are currently explored as a viable solution for transporting high electrical power in the AC regime. In order to be competitive against the DC solution, the cables need to have an acceptable level of AC losses. In this contribution, we discuss the main aspects relevant for designing a cable with a sufficiently low AC loss level. To this end, we perform finite-element-method (FEM) simulations to determine the current and field distributions and calculate the AC losses of such cable configuration. For current capacities of 2-5 kA (peak), power cables are assembled from a relatively small number of MgB2 strands. The performance of such cables strongly depends on the current and field distributions, which are in turn influenced by the number and the arrangement of the superconducting components and also by the magnetic properties of supporting materials. Numerical simulations can help to test different cable configurations and provide important insights for optimizing the cable's design. The numerical model includes the field dependence of the superconductor's critical current density Jc(B) as well as the non-linear properties of magnetic materials.

  11. Improved SCR ac Motor Controller for Battery Powered Urban Electric Vehicles

    NASA Technical Reports Server (NTRS)

    Latos, T. S.

    1982-01-01

    An improved ac motor controller, which when coupled to a standard ac induction motor and a dc propulsion battery would provide a complete electric vehicle power train with the exception of the mechanical transmission and drive wheels was designed. In such a system, the motor controller converts the dc electrical power available at the battery terminals to ac electrical power for the induction motor in response to the drivers commands. The performance requirements of a hypothetical electric vehicle with an upper weight bound of 1590 kg (3500 lb) were used to determine the power rating of the controller. Vehicle acceleration capability, top speed, and gradeability requisites were contained in the Society of Automotive Engineers (SAE) Schedule 227a(d) driving cycle. The important capabilities contained in this driving cycle are a vehicle acceleration requirement of 0 to 72.4 kmph (0 to 45 mph) in 28 seconds a top speed of 88.5 kmph (55 mph), and the ability to negotiate a 10% grade at 48 kmph (30 mph). A 10% grade is defined as one foot of vertical rise per 10 feet of horizontal distance.

  12. SENP1-modulated sumoylation regulates retinoblastoma protein (RB) and Lamin A/C interaction and stabilization.

    PubMed

    Sharma, P; Kuehn, M R

    2016-12-15

    The retinoblastoma tumor suppressor protein (RB) plays a critical role in cell proliferation and differentiation and its inactivation is a frequent underlying factor in tumorigenesis. While the regulation of RB function by phosphorylation is well studied, proteasome-mediated RB protein degradation is emerging as an important regulatory mechanism. Although our understanding of RB turnover is currently limited, there is evidence that the nuclear lamina filament protein Lamin A/C protects RB from proteasomal degradation. Here we show that SUMO1 conjugation of RB and Lamin A/C is modulated by the SUMO protease SENP1 and that sumoylation of both proteins is required for their interaction. Importantly, this SUMO1-dependent complex protects both RB and Lamin A/C from proteasomal turnover.

  13. Correction of the power law of ac conductivity in ion-conducting materials due to the electrode polarization effect.

    PubMed

    Khamzin, A A; Popov, I I; Nigmatullin, R R

    2014-03-01

    Based on the supposition related to fractal nature of transport processes in ion-conducting materials, an expression for the low-frequency ac conductivity dependence was derived. This expression for the ac conductivity generalizes the power-law dependence and gives a possibility to take into account the influence of the electrode polarization effect. The ac conductivity expression obtained is in excellent agreement with experimental data for a wide frequency range.

  14. AC hot carrier effect of the thin-film silicon-on-insulator power n-MOSFET

    NASA Astrophysics Data System (ADS)

    Takenaka, Daiki; Matsumoto, Satoshi

    2017-04-01

    In this paper, we describe the hot carrier (HC) effect of the thin-film silicon-on-insulator (SOI) power n-MOSFET under DC and AC stress. We clarify that the HC effect is enhanced by AC stress because of both drain avalanche hot carriers (DAHC) and channel hot carriers (CHC). In addition, the parasitic bipolar effect which is enhanced by minority carrier accumulation under AC stress, causes device degradation at low frequencies.

  15. First experimental results from DC/DC and AC/DC plasma-based power transformers

    NASA Astrophysics Data System (ADS)

    McEvoy, Aaron; Gibson, William; Nebel, Richard

    2016-10-01

    A plasma-based power transformer has been built and operated in both DC/DC and AC/DC mode. The proprietary Tibbar Plasma Technologies, Inc. transformer design consists of two cylindrically symmetric helical primary electrodes surrounding a low temperature plasma within which a secondary axial current is generated. Initial experimental results have compared well with simulations and moderate conversion efficiencies have been observed. A new proprietary device is currently being constructed that will utilize 3-phase 480 VAC input to achieve higher conversion efficiency and output power. A description of the apparatus and several potential applications will be presented along with preliminary experimental data demonstrating the DC/DC and AC/DC conversion processes. Work performed under ARPA-E contract DE-AR0000677.

  16. Strengthening the SDP Relaxation of AC Power Flows with Convex Envelopes, Bound Tightening, and Valid Inequalities

    DOE PAGES

    Coffrin, Carleton James; Hijazi, Hassan L; Van Hentenryck, Pascal R

    2016-12-01

    Here this work revisits the Semidefine Programming (SDP) relaxation of the AC power flow equations in light of recent results illustrating the benefits of bounds propagation, valid inequalities, and the Convex Quadratic (QC) relaxation. By integrating all of these results into the SDP model a new hybrid relaxation is proposed, which combines the benefits from all of these recent works. This strengthened SDP formulation is evaluated on 71 AC Optimal Power Flow test cases from the NESTA archive and is shown to have an optimality gap of less than 1% on 63 cases. This new hybrid relaxation closes 50% ofmore » the open cases considered, leaving only 8 for future investigation.« less

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

    PubMed

    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 μV(RMS) (CUORE setup) and 90 μV(RMS) (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).

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

    PubMed

    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.

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

    NASA Technical Reports Server (NTRS)

    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).

  20. Advanced Power Regulator Developed for Spacecraft

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The majority of new satellites generate electrical power using photovoltaic solar arrays and store energy in batteries for use during eclipse periods. Careful regulation of battery charging during insolation can greatly increase the expected lifetime of the satellite. The battery charge regulator is usually custom designed for each satellite and its specific mission. Economic competition in the small satellite market requires battery charge regulators that are lightweight, efficient, inexpensive, and modular enough to be used in a wide variety of satellites. A new battery charge regulator topology has been developed at the NASA Lewis Research Center to address these needs. The new regulator topology uses industry-standard dc-dc converters and a unique interconnection to provide size, weight, efficiency, fault tolerance, and modularity benefits over existing systems. A transformer-isolated buck converter is connected such that the high input line is connected in series with the output. This "bypass connection" biases the converter's output onto the solar array voltage. Because of this biasing, the converter only processes the fraction of power necessary to charge the battery above the solar array voltage. Likewise, the same converter hookup can be used to regulate the battery output to the spacecraft power bus with similar fractional power processing. The advantages of this scheme are: 1) Because only a fraction of the power is processed through the dc-dc converter, the single- stage conversion efficiency is 94 to 98 percent; 2) Costly, high-efficiency dc-dc converters are not necessary for high end-to-end system efficiency; 3) The system is highly fault tolerant because the bypass connection will still deliver power if the dc-dc converter fails; and 4) The converters can easily be connected in parallel, allowing higher power systems to be built from a common building block. This new technology will be spaceflight tested in the Photovoltaic Regulator Kit Experiment

  1. Isolated and Passive Power Factor Correction AC/DC Converter for Radioisotope Stirling Generators

    NASA Astrophysics Data System (ADS)

    Garrigos, A.; Blanes, J. M.; Gutierrez, R.; Lizan, J. L.; Carrasco, J. A.; Maset, E.; Montalban, G.; Sanchis-Kilders, E.; Ejea, J. B.; Ferreres, A.

    2014-08-01

    A power processing system is described for low voltage, large inductance, single-phase alternator. This kind of electrical machine appears in Radioisotope Stirling Generators (RSG) as the electrical part attached to the thermodynamic system. The proposed power conditioning system splits into two independent stages; the front-end rectifier performs power factor control by adding a series capacitor in the AC side that forms a resonant filter with the alternator parasitic inductance. Further, the rectifier, thanks to the alternator inductance, behaves as a constant current source that supplies a current-fed, zero-voltage, zero-current push-pull stage. This approach takes advantage of all parasitic elements. Finally, some discussion about linear shunt and reconfigurable power factor filter is provided.

  2. Advanced Power Regulator Developed for Spacecraft

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The majority of new satellites generate electrical power using photovoltaic solar arrays and store energy in batteries for use during eclipse periods. Careful regulation of battery charging during insolation can greatly increase the expected lifetime of the satellite. The battery charge regulator is usually custom designed for each satellite and its specific mission. Economic competition in the small satellite market requires battery charge regulators that are lightweight, efficient, inexpensive, and modular enough to be used in a wide variety of satellites. A new battery charge regulator topology has been developed at the NASA Lewis Research Center to address these needs. The new regulator topology uses industry-standard dc-dc converters and a unique interconnection to provide size, weight, efficiency, fault tolerance, and modularity benefits over existing systems. A transformer-isolated buck converter is connected such that the high input line is connected in series with the output. This "bypass connection" biases the converter's output onto the solar array voltage. Because of this biasing, the converter only processes the fraction of power necessary to charge the battery above the solar array voltage. Likewise, the same converter hookup can be used to regulate the battery output to the spacecraft power bus with similar fractional power processing.

  3. Low-energy hydraulic fracturing wastewater treatment via AC powered electrocoagulation with biochar.

    PubMed

    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.

  4. An Overview of Power Electronics Applications in Fuel Cell Systems: DC and AC Converters

    PubMed Central

    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

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

    PubMed

    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.

  6. Anticipatory regulation of complex power systems

    NASA Astrophysics Data System (ADS)

    Fieno, Thomas Edward

    Electric generation control is performed in a distributed manner to supply power to geographically defined control areas. The goal of generation control is to keep the inadvertent flow of power across a control area's boundary as small as possible. If a difference exists between the power supplied and the power demanded in a control area, the load deficit or surplus would be either borrowed from or stored as the kinetic energy in rotating machines on the grid. This thesis addresses the challenge of matching the power demand of a local area grid with the power delivered by a coal-fired power plant. An anticipatory controller for a model power plant is presented to prescribe the power output into the grid. The control system forecasts what the future demand of the power customers in a control area is likely to be and modifies the fuel input to the power generation facility in order to match the predicted demand. A neural network was found to be an adaptable and robust prediction mechanism for the highly nonlinear data found in the power consumption patterns in a residential area of the Commonwealth Edison grid. The corresponding control schedule of the power plant was tuned to match the anticipated demand using an iterative neural network approach. The use of neural networks and an iterative scheme allows the controller design in this research to be applied to a broad range of control problems. The control methodology presented takes into account limits in the magnitude and rate of control actions. Simulations show that this implementation of anticipatory control of electric power demand is effective and especially well suited to dynamic systems that include a dead time or control limitations. The response of the anticipatory neural network control system was shown to be more energy efficient than feedback control for a typical thermal power regulation facility and to have a much smoother, reduced control effort.

  7. AC/DC Power Systems with Applications for future Lunar/Mars base and Crew Exploration Vehicle

    NASA Technical Reports Server (NTRS)

    Chowdhury, Badrul H.

    2005-01-01

    ABSTRACT The Power Systems branch at JSC faces a number of complex issues as it readies itself for the President's initiative on future space exploration beyond low earth orbit. Some of these preliminary issues - those dealing with electric power generation and distribution on board Mars-bound vehicle and that on Lunar and Martian surface may be summarized as follows: Type of prime mover - Because solar power may not be readily available on parts of the Lunar/Mars surface and also during the long duration flight to Mars, the primary source of power will most likely be nuclear power (Uranium fuel rods) with a secondary source of fuel cell (Hydrogen supply). The electric power generation source - With nuclear power being the main prime mover, the electric power generation source will most likely be an ac generator at a yet to be determined frequency. Thus, a critical issue is whether the generator should generate at constant or variable frequency. This will decide what type of generator to use - whether it is a synchronous machine, an asynchronous induction machine or a switched reluctance machine. The type of power distribution system - the distribution frequency, number of wires (3- wire, 4-wire or higher), and ac/dc hybridization. Building redundancy and fault tolerance in the generation and distribution sub-systems so that the system is safe; provides 100% availability to critical loads; continues to operate even with faulted sub-systems; and requires minimal maintenance. This report descril_es results of a summer faculty fellowship spent in the Power Systems Branch with the specific aim of investigating some of the lessons learned in electric power generation and usage from the terrestrial power systems industry, the aerospace industry as well as NASA's on-going missions so as to recommend novel surface and vehicle-based power systems architectures in support of future space exploration initiatives. A hybrid ac/dc architecture with source side and load side

  8. Plasma antennas driven by 5–20 kHz AC power supply

    SciTech Connect

    Zhao, Jiansen Chen, Yuli; Sun, Yang; Wu, Huafeng; Liu, Yue; Yuan, Qiumeng

    2015-12-15

    The experiments described in this work were performed with the aim of introducing a new plasma antenna that was excited by a 5–20 kHz alternating current (AC) power supply, where the antenna was transformed into a U-shape. The results show that the impedance, voltage standing-wave ratio (VSWR), radiation pattern and gain characteristics of the antenna can be controlled rapidly by varying not only the discharge power, but also by varying the discharge frequency in the range from 5 to 20 kHz. When the discharge frequency is adjusted from 10 to 12 kHz, the gain is higher within a relatively broad frequency band and the switch-on time is less than 1 ms when the discharge power is less than 5 W, meaning that the plasma antenna can be turned on and off rapidly.

  9. Plasma antennas driven by 5-20 kHz AC power supply

    NASA Astrophysics Data System (ADS)

    Zhao, Jiansen; Chen, Yuli; Sun, Yang; Wu, Huafeng; Liu, Yue; Yuan, Qiumeng

    2015-12-01

    The experiments described in this work were performed with the aim of introducing a new plasma antenna that was excited by a 5-20 kHz alternating current (AC) power supply, where the antenna was transformed into a U-shape. The results show that the impedance, voltage standing-wave ratio (VSWR), radiation pattern and gain characteristics of the antenna can be controlled rapidly by varying not only the discharge power, but also by varying the discharge frequency in the range from 5 to 20 kHz. When the discharge frequency is adjusted from 10 to 12 kHz, the gain is higher within a relatively broad frequency band and the switch-on time is less than 1 ms when the discharge power is less than 5 W, meaning that the plasma antenna can be turned on and off rapidly.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Index-based reactive power compensation scheme for voltage regulation

    NASA Astrophysics Data System (ADS)

    Dike, Damian Obioma

    2008-10-01

    Increasing demand for electrical power arising from deregulation and the restrictions posed to the construction of new transmission lines by environment, socioeconomic, and political issues had led to higher grid loading. Consequently, voltage instability has become a major concern, and reactive power support is vital to enhance transmission grid performance. Improved reactive power support to distressed grid is possible through the application of relatively unfamiliar emerging technologies of "Flexible AC Transmission Systems (FACTS)" devices and "Distributed Energy Resources (DERS)." In addition to these infrastructure issues, a lack of situational awareness by system operators can cause major power outages as evidenced by the August 14, 2003 widespread North American blackout. This and many other recent major outages have highlighted the inadequacies of existing power system indexes. In this work, a novel "Index-based reactive compensation scheme" appropriate for both on-line and off-line computation of grid status has been developed. A new voltage stability index (Ls-index) suitable for long transmission lines was developed, simulated, and compared to the existing two-machine modeled L-index. This showed the effect of long distance power wheeling amongst regional transmission organizations. The dissertation further provided models for index modulated voltage source converters (VSC) and index-based load flow analysis of both FACTS and microgrid interconnected power systems using the Newton-Raphson's load flow model incorporated with multi-FACTS devices. The developed package has been made user-friendly through the embodiment of interactive graphical user interface and implemented on the IEEE 14, 30, and 300 bus systems. The results showed reactive compensation has system wide-effect, provided readily accessible system status indicators, ensured seamless DERs interconnection through new islanding modes and enhanced VSC utilization. These outcomes may contribute

  12. Development of an AC power source for CSEM method using full-bridge switching configuration

    NASA Astrophysics Data System (ADS)

    Indrasari, Widyaningrum; Srigutomo, Wahyu; Djamal, Mitra; S, Rahmondia N.

    2015-04-01

    The electromagnetic (EM) method has been widely used in geophysical surveys. It is a non-destructive method that utilizes electromagnetic waves in characterizing subsurface profiles. Generally, EM method can be divided into passive EM and active EM. The passive EM uses the natural electromagnetic field sources, while the active EM or Controlled Source EM (CSEM) uses artificial source to generate electromagnetic wave. In this paper, we present the development of AC power source for CSEM transmitter. As the power source we used AC source with sine wave signal. To satisfy a high power and high voltage in the equipment, we used the full-bridge configuration switching. It works on 990 Hz maximum frequency, and can deliver maximum current of 1.9 A at 620 V. The switching is controlled by microcontroller using Pulse Width Modulation (PWM) and the driver of inverter is built using IGBT. The output frequency can be varied from 1 Hz to 990 Hz. For varied frequencies the harmonic distortion is different due to switching speed. As frequency increase the harmonic distortion also increase. We found that the total harmonic distortion can be reduced to 1 % at the output with 330 Hz.

  13. AC Resonant charger with charge rate unrelated to primary power frequency

    DOEpatents

    Watson, Harold

    1982-01-01

    An AC resonant charger for a capacitive load, such as a PFN, is provided with a variable repetition rate unrelated to the frequency of a multi-phase AC power source by using a control unit to select and couple the phase of the power source to the resonant charger in order to charge the capacitive load with a phase that is the next to begin a half cycle. For optimum range in repetition rate and increased charging voltage, the resonant charger includes a step-up transformer and full-wave rectifier. The next phase selected may then be of either polarity, but is always selected to be of a polarity opposite the polarity of the last phase selected so that the transformer core does not saturate. Thyristors are used to select and couple the correct phase just after its zero crossover in response to a sharp pulse generated by a zero-crossover detector. The thyristor that is turned on then automatically turns off after a full half cycle of its associated phase input. A full-wave rectifier couples the secondary winding of the transformer to the load so that the load capacitance is always charged with the same polarity.

  14. Ac resonant charger with charge rate unrelated to preimary power requency

    DOEpatents

    Not Available

    1979-12-07

    An ac resonant charger for a capacitive load, such as a pulse forming network (PFN), is provided with a variable repetition rate unrelated to the frequency of a multi-phase ac power source by using a control unit to select and couple the phase of the power source to the resonant charger in order to charge the capacitive load with a phase that is the next to begin a half cycle. For optimum range in repetition rate and increased charging voltage, the resonant charger includes a step-up transformer and full-wave rectifier. The next phase selected may then be of either polarity, but is always selected to be of a polarity opposite the polarity of the last phase selected so that the transformer core does not saturate. Thyristors are used to select and couple the correct phase just after its zero crossover in response to a sharp pulse generated by a zero-crossover detector. The thyristor that is turned on then automatically turns off after a full half cycle of its associated phase input. A full-wave rectifier couples the secondary winding of the transformer to the load so that the load capacitance is always charged with the same polarity.

  15. A self-powered AC magnetic sensor based on piezoelectric nanogenerator.

    PubMed

    Yu, Aifang; Song, Ming; Zhang, Yan; Kou, Jinzong; Zhai, Junyi; Lin Wang, Zhong

    2014-11-14

    An AC magnetic field, which is a carrier of information, is distributed everywhere and is continuous. How to use and detect this field has been an ongoing topic over the past few decades. Conventional magnetic sensors are usually based on the Hall Effect, the fluxgate, a superconductor quantum interface or magnetoelectric or magnetoresistive sensing. Here, a flexible, simple, low-cost and self-powered active piezoelectric nanogenerator (NG) is successfully demonstrated as an AC magnetic field sensor at room temperature. The amplitude and frequency of a magnetic field can both be accurately sensed by the NG. The output voltage of the NG has a good linearity with a measured magnetic field. The detected minute magnetic field is as low as 1.2 × 10(-7) tesla, which is 400 times greater than a commercial magnetic sensor that uses the Hall Effect. In comparison to the existing technologies, an NG is a room-temperature self-powered active sensor that is very simple and very cheap for practical applications.

  16. Plasma characteristics of argon glow discharge produced by AC power supply operating at low frequencies

    NASA Astrophysics Data System (ADS)

    Kongpiboolkid, Watcharapon; Mongkolnavin, Rattachat

    2015-04-01

    Non-thermal properties of Argon glow discharge operating with various operating pressures were measured and presented in this work. The Argon plasma is produced by a parallel conducting electrodes coupling with a high voltage AC power supply. The power supply can generate high AC voltage at various frequencies. The frequencies for the operation are in the range of a few kHz. The system is capable of generating electric field between the two metal electrodes discharge system. The characteristics of plasma produced were measured by optical emission spectroscopy (OES) technique where electron temperature (Te) and electron number density (ne) can be determined by line intensity ratio method. The value of electron number density was then determined from the Saha-Eggert equation. Our results show that the electron number density of the discharge obtained is of the order of 10-17 - 10-18 m-3 where the electron temperature is between 1.00-2.00 eV for various operating frequencies used which are in good agreement with similar results published earlier.

  17. Plasma characteristics of argon glow discharge produced by AC power supply operating at low frequencies

    SciTech Connect

    Kongpiboolkid, Watcharapon; Mongkolnavin, Rattachat

    2015-04-24

    Non-thermal properties of Argon glow discharge operating with various operating pressures were measured and presented in this work. The Argon plasma is produced by a parallel conducting electrodes coupling with a high voltage AC power supply. The power supply can generate high AC voltage at various frequencies. The frequencies for the operation are in the range of a few kHz. The system is capable of generating electric field between the two metal electrodes discharge system. The characteristics of plasma produced were measured by optical emission spectroscopy (OES) technique where electron temperature (T{sub e}) and electron number density (n{sub e}) can be determined by line intensity ratio method. The value of electron number density was then determined from the Saha-Eggert equation. Our results show that the electron number density of the discharge obtained is of the order of 10{sup −17} − 10{sup −18} m{sup −3} where the electron temperature is between 1.00−2.00 eV for various operating frequencies used which are in good agreement with similar results published earlier.

  18. Effect of AC target power on AlN film quality

    SciTech Connect

    Knisely, Katherine Grosh, Karl

    2014-09-01

    The influence of alternating current (AC) target power on film stress, roughness, and x-ray diffraction rocking curve full width half maximum (FWHM) was examined for AlN films deposited using S-gun magnetron sputtering on insulative substrates consisting of Si wafers with 575 nm thermal oxide. As the AC target power was increased from 5 to 8 kW, the deposition rate increased from 9.3 to 15.9 A/s, film stress decreased from 81 to −170 MPa, and the rocking curve FWHM increased from 0.98 to 1.03°. AlN film behavior is observed to change with target life; films deposited at 200 kWh target life were approximately 40 MPa more compressive and had 0.02° degree higher rocking curve FWHM values than films deposited at 130 kWh. AlN films deposited in two depositions were compared with films deposited in a single deposition, in order to better characterize the growth behavior and properties of AlN films deposited on an existing AlN film, which is not well understood. Two deposition films, when compared with single deposition films, showed no variation in residual stress trends or grain size behavior, but the average film roughness increased from 0.7 to 1.4 nm and rocking curve FWHM values increased by more than 0.25°.

  19. Single stage AC-DC converter for Galfenol-based micro-power energy harvesters

    NASA Astrophysics Data System (ADS)

    Cavaroc, Peyton; Curtis, Chandra; Naik, Suketu; Cooper, James

    2014-06-01

    Military based sensor systems are often hindered in operational deployment and/or other capabilities due to limitations in their energy storage elements. Typically operating from lithium based batteries, there is a finite amount of stored energy which the sensor can use to collect and transmit data. As a result, the sensors have reduced sensing and transmission rates. However, coupled with the latest advancements in energy harvesting, these sensors could potentially operate at standard sensing and transition rates as well as dramatically extend lifetimes. Working with the magnetostrictive material Galfenol, we demonstrate the production of enough energy to supplement and recharge a solid state battery thereby overcoming the deficiencies faced by unattended sensors. As with any vibration-based energy harvester, this solution produces an alternating current which needs to be rectified and boosted to a level conducive to recharge the storage element. This paper presents a power converter capable of efficiently converting an ultra-low AC voltage to a solid state charging voltage of 4.1VDC. While we are working with Galfenol transducers as our energy source, this converter may also be applied with any AC producing energy harvester, particularly at operating levels less than 2mW and 200mVAC.

  20. Air ion mobility spectra and concentrations upwind and downwind of overhead AC high voltage power lines

    NASA Astrophysics Data System (ADS)

    Wright, Matthew D.; Buckley, Alison J.; Matthews, James C.; Shallcross, Dudley E.; Henshaw, Denis L.

    2014-10-01

    Corona ions produced by high-voltage power lines (HVPLs) can alter the nearby electrical environment, potentially increasing aerosol charge levels downwind. However, there is a lack of knowledge concerning the concentration and mobility of ions from AC HVPLs and their dispersion away from the line. We present ion concentration and mobility measurements made near AC HVPLs in South-West England. Examples of typical mobility spectra are shown highlighting features commonly observed. Corona was observed during 33 of 46 measurements, at 9 of 11 sites, with positive or ‘bipolar' (both polarities) ion production commonly seen. Ion production usually increases atmospheric concentrations by only a modest amount, but extreme cases can enhance concentration by an order of magnitude or more. A polarity imbalance is required to increase aerosol charge via ion attachment; this was observed on 15 of 24 days when positive corona was observed, but was not seen for negative ions. Ion mobility was higher downwind compared with upwind for both ion polarities, but the increase was not statistically significant. Future work should focus on identifying and characterising ‘heavy-producing' HVPLs, and obtaining results in conditions which may favour negative ion production e.g. high humidity, inclement weather or during nighttime.

  1. Development of a single-phase harmonic power flow program to study the 20 kHz AC power system for large spacecraft

    NASA Technical Reports Server (NTRS)

    Kraft, L. Alan; Kankam, M. David

    1991-01-01

    The development of software is described to aid in design and analysis of AC power systems for large spacecraft. The algorithm is an important version of harmonic power flow program, HARMFLO, used for the study of AC power quality. The new program is applicable to three-phase systems typified by terrestrial power systems, and single-phase systems characteristic of space power systems. The modified HARMFLO accommodates system operating frequencies ranging from terrestrial 60 Hz to and beyond aerospace 20 kHz, and can handle both source and load-end harmonic distortions. Comparison of simulation and test results of a representative spacecraft power system shows a satisfactory correlation. Recommendations are made for the direction of future improvements to the software, to enhance its usefulness to power system designer and analysts.

  2. Resonant AC power system proof-of-concept test program, volume 2, appendix 1

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This report contains two volumes. The main text (Volume 1) summarizes the tests results and gives a detailed discussion of the response of three early, first generation configurations of ac power system IRAD breadboards to the contracted tests imposed on them. It explains photographs, measurements, and data calculations, as well as any observed anomalies or lessons learned. This volume (No 2, Appendix 1, Test Results and Data), published under separate cover, includes all of the data taken on the 1.0 kW single-phase; 5.0 kW three-phase; and 25.0-kW three-phase system breadboards. The format of this data is raw, i.e., it is a direct copy of the data sheets for the test data notebook.

  3. Spectral response of atmospheric electric field measurements near AC high voltage power lines

    NASA Astrophysics Data System (ADS)

    Silva, H. G.; Matthews, J. C.; Wright, M. D.; Shallcross, D. E.

    2015-10-01

    To understand the influence of corona ion emission on the atmospheric electrical field, measurements were made near to two AC high voltage power lines. A JCI 131 field-mill recorded the atmospheric electric field over one year. Meteorological measurements were also taken. The data series is divided in four zones (dependent on wind direction): whole zones, Z0; zone 1, Z1; zone 2, Z2; zone 3, Z3. Z3 is the least affected by corona ion emission and for that reason it is used as a reference against Z1 and Z2, which are strongly influenced by this phenomena. Analysis was undertaken for all weather days and dry days only. The Lomb-Scargle strategy developed for unevenly spaced time-series is used to calculate the spectral response of the aforementioned zones. Only frequencies above 1 minute are considered.

  4. Novel multijunction thermal converter in planar technique for AC current, voltage, power and optical radiation measurement

    NASA Astrophysics Data System (ADS)

    Klonz, M.; Weimann, T.

    1990-05-01

    A new planar thin film design of multijunction thermocouples on a silicon chip containing a window with a SiO2-membrane for low heat conductance underneath of the thermocouples is described. It is used as the sensor for the temperature difference in a multijunction thermal converter for ac-dc transfer of electrical quantities like voltage, current and power via Joule heat in a thin film resistor. By coating the heater with an optically absorbing layer it is used as a highly sensitive radiometer transferring absorbed energy to Joule heat in the resistor. The design can easily be optimized for all different frequency applications. It offers the possibility of the mass production of transfer standards at highest level of accuracy.

  5. Lyn regulates mucus secretion and MUC5AC via the STAT6 signaling pathway during allergic airway inflammation

    PubMed Central

    Wang, Xiaoyun; Li, Yin; Luo, Deyu; Wang, Xing; Zhang, Yun; Liu, Zhigang; Zhong, Nanshan; Wu, Min; Li, Guoping

    2017-01-01

    Hypersecretion of mucus is an important component of airway remodeling and contributes to the mucus plugs and airflow obstruction associated with severe asthma phenotypes. Lyn has been shown to down-regulate allergen-induced airway inflammation. However, the role of Lyn in mucin gene expression remains unresolved. In this study, we first demonstrate that Lyn overexpression decreased the mucus hypersecretion and levels of the muc5ac transcript in mice exposed to ovalbumin (OVA). Lyn overexpression also decreased the infiltration of inflammatory cells and the levels of IL-13 and IL-4 in OVA-challenged airways. Whereas Lyn knockdown increased the IL-4 or IL-13-induced MUC5AC transcript and protein levels in the human bronchial epithelial cell line, 16HBE, Lyn overexpression decreased IL-4- or IL-13-induced MUC5AC transcript and protein levels. Overexpression of Lyn also decreased the expression and phosphorylation of STAT6 in OVA-exposed mice, whereas Lyn knockdown increased STAT6 and MUC5AC levels in 16HBE cells. Finally, chromatin immunoprecipitation analysis confirmed that Lyn overexpression decreased the binding of STAT6 to the promoter region of Muc5ac in mice exposed to OVA. Collectively, these findings demonstrated that Lyn overexpression ameliorated airway mucus hypersecretion by down-regulating STAT6 and its binding to the MUC5AC promoter. PMID:28205598

  6. Input Voltage Loop Control with AC Current Feedback for Buck Boost Regulators (B2R) Used as Solar Array Regulators

    NASA Astrophysics Data System (ADS)

    Mourra, Olivier; Fernandez, Arturo; Tonicello, Ferdinando

    2014-08-01

    In a satellite, the main function of a Power Conditioning Unit is to manage the energy coming from several power sources (usually solar arrays and battery) and to deliver it continuously to the users in an appropriate form during the overall mission. Solar Array Regulators are used to extract the power from the SA in order to recharge the battery and to supply the loads during sunlight. The objective of this paper is to present a control technique that can be used when segregated buck, boost or buck boost SAR are implemented. The paper demonstrate theoretically and experimentally the feasibility of this technique.

  7. Programmable high voltage power supply with regulation confined to the high voltage section

    NASA Technical Reports Server (NTRS)

    Castell, Karen D. (Inventor); Ruitberg, Arthur P. (Inventor)

    1994-01-01

    A high voltage power supply in a dc-dc converter configuration includes a pre-regulator which filters and regulates the dc input and drives an oscillator which applies, in turn, a low voltage ac signal to the low side of a step-up high voltage transformer. The high voltage side of the transformer drives a voltage multiplier which provides a stepped up dc voltage to an output filter. The output voltage is sensed by a feedback network which then controls a regulator. Both the input and output of the regulator are on the high voltage side, avoiding isolation problems. The regulator furnishes a portion of the drive to the voltage multiplier, avoiding having a regulator in series with the load with its attendant, relatively high power losses. This power supply is highly regulated, has low power consumption, a low parts count and may be manufactured at low cost. The power supply has a programmability feature that allows for the selection of a large range of output voltages.

  8. Reliable, Efficient and Cost-Effective Electric Power Converter for Small Wind Turbines Based on AC-link Technology

    SciTech Connect

    Darren Hammell; Mark Holveck; DOE Project Officer - Keith Bennett

    2006-08-01

    Grid-tied inverter power electronics have been an Achilles heel of the small wind industry, providing opportunity for new technologies to provide lower costs, greater efficiency, and improved reliability. The small wind turbine market is also moving towards the 50-100kW size range. The unique AC-link power conversion technology provides efficiency, reliability, and power quality advantages over existing technologies, and Princeton Power will adapt prototype designs used for industrial asynchronous motor control to a 50kW small wind turbine design.

  9. In silico synchronization reveals regulators of nuclear ruptures in lamin A/C deficient model cells

    NASA Astrophysics Data System (ADS)

    Robijns, J.; Molenberghs, F.; Sieprath, T.; Corne, T. D. J.; Verschuuren, M.; de Vos, W. H.

    2016-07-01

    The nuclear lamina is a critical regulator of nuclear structure and function. Nuclei from laminopathy patient cells experience repetitive disruptions of the nuclear envelope, causing transient intermingling of nuclear and cytoplasmic components. The exact causes and consequences of these events are not fully understood, but their stochastic occurrence complicates in-depth analyses. To resolve this, we have established a method that enables quantitative investigation of spontaneous nuclear ruptures, based on co-expression of a firmly bound nuclear reference marker and a fluorescent protein that shuttles between the nucleus and cytoplasm during ruptures. Minimally invasive imaging of both reporters, combined with automated tracking and in silico synchronization of individual rupture events, allowed extracting information on rupture frequency and recovery kinetics. Using this approach, we found that rupture frequency correlates inversely with lamin A/C levels, and can be reduced in genome-edited LMNA knockout cells by blocking actomyosin contractility or inhibiting the acetyl-transferase protein NAT10. Nuclear signal recovery followed a kinetic that is co-determined by the severity of the rupture event, and could be prolonged by knockdown of the ESCRT-III complex component CHMP4B. In conclusion, our approach reveals regulators of nuclear rupture induction and repair, which may have critical roles in disease development.

  10. In silico synchronization reveals regulators of nuclear ruptures in lamin A/C deficient model cells

    PubMed Central

    Robijns, J.; Molenberghs, F.; Sieprath, T.; Corne, T. D. J.; Verschuuren, M.; De Vos, W. H.

    2016-01-01

    The nuclear lamina is a critical regulator of nuclear structure and function. Nuclei from laminopathy patient cells experience repetitive disruptions of the nuclear envelope, causing transient intermingling of nuclear and cytoplasmic components. The exact causes and consequences of these events are not fully understood, but their stochastic occurrence complicates in-depth analyses. To resolve this, we have established a method that enables quantitative investigation of spontaneous nuclear ruptures, based on co-expression of a firmly bound nuclear reference marker and a fluorescent protein that shuttles between the nucleus and cytoplasm during ruptures. Minimally invasive imaging of both reporters, combined with automated tracking and in silico synchronization of individual rupture events, allowed extracting information on rupture frequency and recovery kinetics. Using this approach, we found that rupture frequency correlates inversely with lamin A/C levels, and can be reduced in genome-edited LMNA knockout cells by blocking actomyosin contractility or inhibiting the acetyl-transferase protein NAT10. Nuclear signal recovery followed a kinetic that is co-determined by the severity of the rupture event, and could be prolonged by knockdown of the ESCRT-III complex component CHMP4B. In conclusion, our approach reveals regulators of nuclear rupture induction and repair, which may have critical roles in disease development. PMID:27461848

  11. Nearly Unity Power-Factor of the Modular Three-Phase AC to DC Converter with Minimized DC Bus Capacitor

    NASA Astrophysics Data System (ADS)

    Chunkag, Viboon; Kamnarn, Uthen

    The analysis and design of nearly unity power-factor and fast dynamic response of the modular three-phase ac to dc converter using three single-phase isolated SEPIC rectifier modules with minimized dc bus capacitor is discussed, based on power balance control technique. The averaged small-signal technique is used to obtain the inductor current compensator, thus resulting in the output impedance and audio susceptibility become zero, that is, the output voltage of the converter presented in this paper is independent of the variations of the dc load current and the utility voltage. The proposed system significantly improves the dynamic response of the converter to load steps with minimized dc bus capacitor for Distributed Power System (DPS). A 600W prototype modular three-phase ac to dc converter comprising three 200W single-phase SEPIC rectifier modules with the proposed control scheme has been designed and implemented. The proposed system is confirmed by experimental implementation.

  12. AC electrokinetic drug delivery in dentistry using an interdigitated electrode assembly powered by inductive coupling.

    PubMed

    Ivanoff, Chris S; Wu, Jie Jayne; Mirzajani, Hadi; Cheng, Cheng; Yuan, Quan; Kevorkyan, Stepan; Gaydarova, Radostina; Tomlekova, Desislava

    2016-10-01

    AC electrokinetics (ACEK) has been shown to deliver certain drugs into human teeth more effectively than diffusion. However, using electrical wires to power intraoral ACEK devices poses risks to patients. The study demonstrates a novel interdigitated electrode arrays (IDE) assembly powered by inductive coupling to induce ACEK effects at appropriate frequencies to motivate drugs wirelessly. A signal generator produces the modulating signal, which multiplies with the carrier signal to produce the amplitude modulated (AM) signal. The AM signal goes through the inductive link to appear on the secondary coil, then rectified and filtered to dispose of its carrier signal, and the positive half of the modulating signal appears on the load. After characterizing the device, the device is validated under light microscopy by motivating carboxylate-modified microspheres, tetracycline, acetaminophen, benzocaine, lidocaine and carbamide peroxide particles with induced ACEK effects. The assembly is finally tested in a common dental bleaching application. After applying 35 % carbamide peroxide to human teeth topically or with the IDE at 1200 Hz, 5 Vpp for 20 min, spectrophotometric analysis showed that compared to diffusion, the IDE enhanced whitening in specular optic and specular optic excluded modes by 215 % and 194 % respectively. Carbamide peroxide absorbance by the ACEK group was two times greater than diffusion as measured by colorimetric oxidation-reduction and UV-Vis spectroscopy at 550 nm. The device motivates drugs of variable molecular weight and structure wirelessly. Wireless transport of drugs to intraoral targets under ACEK effects may potentially improve the efficacy and safety of drug delivery in dentistry.

  13. Non-raft adenylyl cyclase 2 defines a cAMP signaling compartment that selectively regulates IL-6 expression in airway smooth muscle cells: differential regulation of gene expression by AC isoforms.

    PubMed

    Bogard, Amy S; Birg, Anna V; Ostrom, Rennolds S

    2014-04-01

    Adenylyl cyclase (AC) isoforms differ in their tissue distribution, cellular localization, regulation, and protein interactions. Most cell types express multiple AC isoforms. We hypothesized that cAMP produced by different AC isoforms regulates unique cellular responses in human bronchial smooth muscle cells (BSMC). Overexpression of AC2, AC3, or AC6 had distinct effects on forskolin (Fsk)-induced expression of a number of known cAMP-responsive genes. These data show that different AC isoforms can differentially regulate gene expression. Most notable, overexpression and activation of AC2 enhanced interleukin 6 (IL-6) expression, but overexpression of AC3 or AC6 had no effect. IL-6 production by BSMC was induced by Fsk and select G protein-coupled receptor (GPCR) agonists, though IL-6 levels did not directly correlate with global cAMP levels. Treatment with PKA selective 6-Bnz-cAMP or Epac selective 8-CPT-2Me-cAMP cAMP analogs revealed a predominant role for PKA in cAMP-mediated induction of IL-6. IL-6 promoter mutations demonstrated that AP-1 and CRE transcription sites were required for Fsk to stimulate IL-6 expression. Our present study defines an AC2 cAMP signaling compartment that specifically regulates IL-6 expression in BSMC via Epac and PKA and demonstrates that other AC isoforms are excluded from this pool.

  14. Pulse doubling in zigzag-connected autotransformer-based 12-pulse ac-dc converter for power quality improvement

    NASA Astrophysics Data System (ADS)

    Abdollahi, Rohollah

    2012-12-01

    This paper presents a pulse doubling technique in a 12-pulse ac-dc converter which supplies direct torque controlled motor drives (DTCIMDs) in order to have better power quality conditions at the point of common coupling. The proposed technique increases the number of rectification pulses without significant changes in the installations and yields in harmonic reduction in both ac and dc sides. The 12-pulse rectified output voltage is accomplished via two paralleled six-pulse acdc converters each of them consisting of three-phase diode bridge rectifiers. An autotransformer is designed to supply the rectifiers. The design procedure of magnetics is in a way such that makes it suitable for retrofit applications where a six-pulse diode bridge rectifier is being utilized. Independent operation of paralleled diode-bridge rectifiers, i.e. dc-ripple re-injection methodology, requires a Zero Sequence Blocking Transformer (ZSBT). Finally, a tapped interphase reactor is connected at the output of ZSBT to double the pulse numbers of output voltage up to 24 pulses. The aforementioned structure improves power quality criteria at ac mains and makes them consistent with the IEEE-519 standard requirements for varying loads. Furthermore, near unity power factor is obtained for a wide range of DTCIMD operation. A comparison is made between 6-pulse, 12-pulse, and proposed converters from view point of power quality indices. Results show that input current total harmonic distortion (THD) is less than 5% for the proposed topology at various loads.

  15. Caspase-2 and microRNA34a/c regulate lidocaine-induced dorsal root ganglia apoptosis in vitro.

    PubMed

    Li, Yandong; Jia, Zhi; Zhang, Laizhu; Wang, Jianguo; Yin, Guangming

    2015-11-15

    Epidural administration of lidocaine may cause neurotoxicity in spinal cord dorsal root ganglia neurons (DRGNs). In this study, we explored the underling mechanisms of apoptotic pathways of lidocaine-induced apoptosis in DRGNs. Neonatal rat DRGNs were treated with lidocaine to induced apoptosis in vitro. Western blot showed caspase- (casp-) 2/3/9 proteins were all upregulated by lidocaine in DRGNs. However, inhibition of casp-2 protected lidocaine-induced apoptosis in DRGNs, whereas Casp3/9 inhibition did not. The possible upstream epigenetic regulators of casp-2, microRNA-34 (miR-34) family, including miR-34a/b/c, were evaluated by dual-luciferase reporter assay and qRT-PCR. We found miR-34a/c, but not miR-34b, were down-regulated in lidocaine-induced DRGN apoptosis. Subsequent upregulation of miR-34 family showed miR-34a/c were able to inhibit casp-2 and protect lidocaine-induced apoptosis in DRGNs, whereas miR-34b did not. Thus, out study shows that casp-2, in association with miR-34a/c was actively involved in lidocaine-induced apoptosis in DRGNs. Inhibiting casp-2 or upregulating miR-34a/c may provide novel meanings to protect local anesthetic-induced neurotoxicity.

  16. Sub-micrometer particles produced by a low-powered AC electric arc in liquids.

    PubMed

    Jaworski, Jacek A; Fleury, Eric

    2012-01-01

    The article presents the report of the production of composites of sub-micrometer metal particles in matrix consisted of the metal compounds by means of an AC electric arc in water and paraffin solutions using electrodes carbon-metal and metal-metal (metal: Ni, Fe, Co, Cu). The advantage of this method is the low electric power (from 5 to 10 W) needed in comparison to standard DC arc-discharge methods (0.8 to 3 kW). This method enables the production of particles from conductive material also in wide range of temperature and in solvent which could be either transparent to light or opaque. Moreover the solvent can be electrolyte or insulating liquid. The microstructure of the composite layer was investigated by scanning electron microscopy (SEM), Electron Probe Microanalysis (EPMA) and X-ray. During particles production in water metal oxides were created. Additionally using cobalt-copper, nickel-copper as couple electrodes, insoluble in water copper (II) hydroxide crystal grains were created additionally which crystals shape was depended on transition metal. For iron-copper couple electrodes system the copper (II) hydroxide was not formed. Experiments with sequence production of Ni and Fe particles with C electrode assisting in molten paraffin let to obtain both Ni and Fe particles surrounded by paraffin. After solidification the material was insulator but if locally magnetic field influenced on the liquid solution in that place after solidification a new composite was created which was electric current conductor with resistivity around 0.1 omega x m, was attracted by magnetic field and presented magneto resistance around 0.4% in changing magnetic field in a range 150 mT. After mixing the concentrated paraffin with normal paraffin resistivity of the mixture increased and it became photosensitive and created small voltage under light influence.

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

    SciTech Connect

    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.

  18. AC/DC converter

    NASA Astrophysics Data System (ADS)

    Jain, Praveen K.

    1992-08-01

    In a system such as a 20 kHz space station primary electrical power distribution system, power conversion from AC to DC is required. Some of the basic requirements for this conversion are high efficiency, light weight and small volume, regulated output voltage, close to unity input power factor, distortionless input current, soft-starting, low electromagnetic interference, and high reliability. An AC-to-DC converter is disclosed which satisfies the main design objectives of such converters for use in space. The converter of the invention comprises an input transformer, a resonant network, a current controller, a diode rectifier, and an output filter. The input transformer is for connection to a single phase, high frequency, sinusoidal waveform AC voltage source and provides a matching voltage isolating from the AC source. The resonant network converts this voltage to a sinusoidal, high frequency bidirectional current output, which is received by the current controller to provide the desired output current. The diode rectifier is connected in parallel with the current controller to convert the bidirectional current into a unidirectional current output. The output filter is connected to the rectifier to provide an essentially ripple-free, substantially constant voltage DC output.

  19. Acetylated α-Tubulin Regulated by N-Acetyl-Seryl-Aspartyl-Lysyl-Proline(Ac-SDKP) Exerts the Anti-fibrotic Effect in Rat Lung Fibrosis Induced by Silica

    PubMed Central

    Xiaojun, Wang; Yan, Liu; Hong, Xu; Xianghong, Zhang; Shifeng, Li; Dingjie, Xu; Xuemin, Gao; Lijuan, Zhang; Bonan, Zhang; Zhongqiu, Wei; Ruimin, Wang; Brann, Darrell; Fang, Yang

    2016-01-01

    Silicosis is the most serious occupational disease in China. The objective of this study was to screen various proteins related to mechanisms of the pathogenesis of silicosis underlying the anti-fibrotic effect of N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) using proteomic profile analysis. We also aimed to explore a potential mechanism of acetylated α-tubulin (α-Ac-Tub) regulation by Ac-SDKP. Two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were used to assess the different protein expression profiles between control and silicosis rats treated with or without Ac-SDKP. Twenty-nine proteins were identified to be potentially involved in the progression of silicosis and the anti-fibrotic effect of Ac-SDKP. Our current study finds that 1) the lost expression of Ac-Tub-α may be a new mechanism in rat silicosis; 2) treatment of silicotic rats with N-acetyl-Seryl-Aspartyl-Lysyl-Proline (Ac-SDKP) inhibits myofibroblast differentiation and collagen deposition accompanied by stabilizing the expression of α-Ac-Tub in vivo and in vitro, which is related with deacetylase family member 6 (HDAC6) and α-tubulin acetyl transferase (α-TAT1). Our data suggest that α-Ac-Tub regulation by Ac-SDKP may potentially be a new anti-fibrosis mechanism. PMID:27577858

  20. Akt-mTORC1 signaling regulates Acly to integrate metabolic input to control of macrophage activation

    PubMed Central

    Covarrubias, Anthony J; Aksoylar, Halil Ibrahim; Yu, Jiujiu; Snyder, Nathaniel W; Worth, Andrew J; Iyer, Shankar S; Wang, Jiawei; Ben-Sahra, Issam; Byles, Vanessa; Polynne-Stapornkul, Tiffany; Espinosa, Erika C; Lamming, Dudley; Manning, Brendan D; Zhang, Yijing; Blair, Ian A; Horng, Tiffany

    2016-01-01

    Macrophage activation/polarization to distinct functional states is critically supported by metabolic shifts. How polarizing signals coordinate metabolic and functional reprogramming, and the potential implications for control of macrophage activation, remains poorly understood. Here we show that IL-4 signaling co-opts the Akt-mTORC1 pathway to regulate Acly, a key enzyme in Ac-CoA synthesis, leading to increased histone acetylation and M2 gene induction. Only a subset of M2 genes is controlled in this way, including those regulating cellular proliferation and chemokine production. Moreover, metabolic signals impinge on the Akt-mTORC1 axis for such control of M2 activation. We propose that Akt-mTORC1 signaling calibrates metabolic state to energetically demanding aspects of M2 activation, which may define a new role for metabolism in supporting macrophage activation. DOI: http://dx.doi.org/10.7554/eLife.11612.001 PMID:26894960

  1. Akt-mTORC1 signaling regulates Acly to integrate metabolic input to control of macrophage activation.

    PubMed

    Covarrubias, Anthony J; Aksoylar, Halil Ibrahim; Yu, Jiujiu; Snyder, Nathaniel W; Worth, Andrew J; Iyer, Shankar S; Wang, Jiawei; Ben-Sahra, Issam; Byles, Vanessa; Polynne-Stapornkul, Tiffany; Espinosa, Erika C; Lamming, Dudley; Manning, Brendan D; Zhang, Yijing; Blair, Ian A; Horng, Tiffany

    2016-02-19

    Macrophage activation/polarization to distinct functional states is critically supported by metabolic shifts. How polarizing signals coordinate metabolic and functional reprogramming, and the potential implications for control of macrophage activation, remains poorly understood. Here we show that IL-4 signaling co-opts the Akt-mTORC1 pathway to regulate Acly, a key enzyme in Ac-CoA synthesis, leading to increased histone acetylation and M2 gene induction. Only a subset of M2 genes is controlled in this way, including those regulating cellular proliferation and chemokine production. Moreover, metabolic signals impinge on the Akt-mTORC1 axis for such control of M2 activation. We propose that Akt-mTORC1 signaling calibrates metabolic state to energetically demanding aspects of M2 activation, which may define a new role for metabolism in supporting macrophage activation.

  2. Functional Regulation of an Autographa californica Nucleopolyhedrovirus-Encoded MicroRNA, AcMNPV-miR-1, in Baculovirus Replication

    PubMed Central

    Zhu, Mengxiao; Deng, Riqiang

    2016-01-01

    ABSTRACT An Autographa californica nucleopolyhedrovirus-encoded microRNA (miRNA), AcMNPV-miR-1, downregulates the ac94 gene, reducing the production of infectious budded virions and accelerating the formation of occlusion-derived virions. In the current study, four viruses that constitutively overexpress AcMNPV-miR-1 were constructed to further explore the function of the miRNA. In addition to the ac94 gene, two new viral gene targets (ac18 and ac95) of AcMNPV-miR-1 were identified, and the possible interacting proteins were verified and tested. In the context of AcMNPV-miR-1 overexpression, ac18 was slightly upregulated, and ac95 was downregulated. Several interacting proteins were identified, and a functional pathway for AcMNPV-miR-1 was deduced. AcMNPV-miR-1 overexpression decreased budded virus infectivity, reduced viral DNA replication, accelerated polyhedron formation, and promoted viral infection efficiency in Trichoplusia ni larvae, suggesting that AcMNPV-miR-1 restrains virus infection of cells but facilitates virus infection of larvae. IMPORTANCE Recently, microRNAs (miRNAs) have been widely reported as moderators or regulators of mammalian cellular processes, especially disease-related pathways in humans. However, the roles played by miRNAs encoded by baculoviruses, which infect numerous beneficial insects and agricultural pests, have rarely been described. To explore the actions of virus-encoded miRNAs, we investigated an miRNA encoded by Autographa californica nucleopolyhedrovirus (AcMNPV-miR-1). We previously identified this miRNA through the exogenous addition of AcMNPV-miR-1 mimics. In the current study, we constitutively overexpressed AcMNPV-miR-1 and analyzed the resultant effects to more comprehensively assess what is indeed the function of this miRNA during viral infection. In addition, we widely explored the target genes for the miRNA in the viral and host genomes and proposed a possible functional network for AcMNPV-miR-1, which provides a

  3. NEW APPROACHES: Investigating power, work and effective values in an AC resistive circuit through a microcomputer-based laboratory

    NASA Astrophysics Data System (ADS)

    Trumper, Ricardo; Gelbman, Moshe

    1997-11-01

    Microcomputer-based laboratory (MBL) tools have been developed which interface with a great variety of computers. Students use these tools to collect physical data in real time which can later be manipulated and analysed. This new investigative method together with a high standard of precision enables students to investigate many principles of physics that have not previously been feasible. In this article we describe some examples of experiments designed for high-school students with the help of the MBL Explorer. We mainly analyse power, work and effective (RMS) values in an AC resistive circuit.

  4. Linear Averaged and Sampled Data Models for Large Signal Control of High Power Factor AC-DC Converters

    DTIC Science & Technology

    1990-06-01

    design a digital controller for the outer trol schemes for high power factor ac to dc converters, loop, including PI control , and presents simulation re...design of an analog control (e.g. PI control ) for by the current loop. If kin] is too large, then the inductor tam el (3) Isnoar ts ee lin at tne. Fcorl...with PI Control 6 mm am I m mmmmimmm~mmml r .14 _ _ _ _ _ _ _ _ _ _ O .12 SM .16 .p N 17 .6 Is , TV 240 6 F tic .04 113 .02 a I I ’ 190 0 0.973 I • 0

  5. Utility-Scale Power Router: Dynamic Control of Grid Assets Using Direct AC Converter Cells

    SciTech Connect

    2010-09-01

    ADEPT Project: Georgia Tech is developing a cost-effective, utility-scale power router that uses an enhanced transformer to more efficiently direct power on the grid. Existing power routing technologies are too expensive for widespread use, but the ability to route grid power to match real-time demand and power outages would significantly reduce energy costs for utilities, municipalities, and consumers. Georgia Tech is adding a power converter to an existing grid transformer to better control power flows at about 1/10th the cost of existing power routing solutions. Transformers convert the high-voltage electricity that is transmitted through the grid into the low-voltage electricity that is used by homes and businesses. The added converter uses fewer steps to convert some types of power and eliminates unnecessary power storage, among other improvements. The enhanced transformer is more efficient, and it would still work even if the converter fails, ensuring grid reliability.

  6. A novel ZePoC encoder for sinusoidal signals with a predictable accuracy for an AC power standard

    NASA Astrophysics Data System (ADS)

    Vennemann, T.; Frye, T.; Liu, Z.; Kahmann, M.; Mathis, W.

    2015-11-01

    In this paper we present an analytical formulation of a Zero Position Coding (ZePoC) encoder for an AC power standard based on class-D topologies. For controlling a class-D power stage a binary signal with special spectral characteristics will be generated by this ZePoC encoder for sinusoidal signals. These spectral characteristics have a predictable accuracy within a separated baseband to keep the noise floor below a specified level. Simulation results will validate the accuracy of this novel ZePoC encoder. For a real-time implementation of the encoder on a DSP/FPGA hardware architecture a trade-off between accuracy and speed of the ZePoC algorithm has to be made. Therefore the numerical effects of different floating point formats will be analyzed.

  7. AC/DC Smart Control And Power Sharing of DC Distribution Systems

    DTIC Science & Technology

    2012-02-10

    Thesis submitted in partial requirement for the degree of MASTER OF SCIENCE in ELECTRICAL ENGINEERING by Mohamed Anwar Elshaer 2012...will play vital role in electric power systems. It allows residents and businesses the potential to generate electrical energy to sell surplus power...better method for electrical power delivery. This concept is inspired by the possibility of efficient integration of small distributed generation

  8. Development of a Portable AC/DC Welding Power Supply Module

    DTIC Science & Technology

    1975-03-01

    proper time sequence to the SCR contactor ( SCR1 to SCR3, Drawing NO . 1001, Figure IV-A). The zero crossover detector consists of a power supply (JR5...as far as circuit operation is concerned. The voltage on the anode of SCR1 then rises to a positive value as the line voltage crosses zero. When the...pulse to the gate of SCR1 C34 then rapidly d i s c h a r g e s . The power supply is a critical part of the circuit operation. The input power comes

  9. High-frequency AC/DC converter with unity power factor and minimum harmonic distortion

    SciTech Connect

    Wernekinch, E.R.

    1987-01-01

    The power factor is controlled by adjusting the relative position of the fundamental component of an optimized PWM-type voltage with respect to the supply voltage. Current harmonic distortion is minimized by the use of optimized firing angles for the converter at a frequency where GTO's can be used. This feature makes this approach very attractive at power levels of 100 to 600 kW. To obtain the optimized PWM pattern, a steepest descent digital computer algorithm is used. Digital-computer simulations are performed and a low-power model is constructed and tested to verify the concepts and the behavior of the model. Experimental results show that unity power factor is achieved and that the distortion in the phase currents is 10.4% at 90% of full load. This is less than achievable with sinusoidal PWM, harmonic elimination, hysteresis control, and deadbeat control for the same switching frequency.

  10. 21 CFR 880.5510 - Non-AC-powered patient lift.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic... hydraulic, battery, or mechanically powered device, either fixed or mobile, used to lift and transport...

  11. 21 CFR 880.5510 - Non-AC-powered patient lift.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic... hydraulic, battery, or mechanically powered device, either fixed or mobile, used to lift and transport...

  12. Power conversion distribution system using a resonant high-frequency AC link

    NASA Technical Reports Server (NTRS)

    Sood, P. K.; Lipo, T. A.

    1986-01-01

    Static power conversion systems based on a resonant high frequency (HF) link offers a significant reduction in the size and weight of the equipment over that achieved with conventional approaches, especially when multiple sources and loads are to be integrated. A faster system response and absence of audible noise are the other principal characteristics of such systems. A conversion configuration based on a HF link which is suitable for applications requiring distributed power is proposed.

  13. Experience in connecting the power generating units of thermal power plants to automatic secondary frequency regulation within the united power system of Russia

    SciTech Connect

    Zhukov, A. V.; Komarov, A. N.; Safronov, A. N.; Barsukov, I. V.

    2009-05-15

    The principles of central control of the power generating units of thermal power plants by automatic secondary frequency and active power overcurrent regulation systems, and the algorithms for interactions between automatic power control systems for the power production units in thermal power plants and centralized systems for automatic frequency and power regulation, are discussed. The order of switching the power generating units of thermal power plants over to control by a centralized system for automatic frequency and power regulation and by the Central Coordinating System for automatic frequency and power regulation is presented. The results of full-scale system tests of the control of power generating units of the Kirishskaya, Stavropol, and Perm GRES (State Regional Electric Power Plants) by the Central Coordinating System for automatic frequency and power regulation at the United Power System of Russia on September 23-25, 2008, are reported.

  14. Voltage Regulator Chip: Power Supplies on a Chip

    SciTech Connect

    2010-09-01

    ADEPT Project: CPES at Virginia Tech is finding ways to save real estate on a computer's motherboard that could be used for other critical functions. Every computer processor today contains a voltage regulator that automatically maintains a constant level of electricity entering the device. These regulators contain bulky components and take up about 30% of a computer's motherboard. CPES at Virginia Tech is developing a voltage regulator that uses semiconductors made of gallium nitride on silicon (GaN-on-Si) and high-frequency soft magnetic material. These materials are integrated on a small, 3D chip that can handle the same amount of power as traditional voltage regulators at 1/10 the size and with improved efficiency. The small size also frees up to 90% of the motherboard space occupied by current voltage regulators.

  15. A new on-chip all-digital three-phase full-bridge dc/ac power inverter with feedforward and frequency control techniques.

    PubMed

    Chen, Jiann-Jong; Kung, Che-Min

    2010-09-01

    The communication speed between components is far from satisfactory. To achieve high speed, simple control system configuration, and low cost, a new on-chip all-digital three-phase dc/ac power inverter using feedforward and frequency control techniques is proposed. The controller of the proposed power inverter, called the shift register, consists of six-stage D-latch flip-flops with a goal of achieving low-power consumption and area efficiency. Variable frequency is achieved by controlling the clocks of the shift register. One advantage regarding the data signal (D) and the common clock (CK) is that, regardless of the phase difference between the two, all of the D-latch flip-flops are capable of delaying data by one CK period. To ensure stability, the frequency of CK must be six times higher than that of D. The operation frequency of the proposed power inverter ranges from 10 Hz to 2 MHz, and the maximum output loading current is 0.8 A. The prototype of the proposed circuit has been fabricated with TSMC 0.35 μm 2P4M CMOS processes. The total chip area is 2.333 x 1.698 mm2. The three-phase dc/ac power inverter is applicable in uninterrupted power supplies, cold cathode fluorescent lamps, and motors, because of its ability to convert the dc supply voltage into the three-phase ac power sources.

  16. Nonlinear Compensation of Solar Array Simulators with Dual Power Regulation

    NASA Astrophysics Data System (ADS)

    Mizrah, E. A.; Tkachev, S. B.; Poymanov, D. N.; Fedchenko, A. S.

    2016-11-01

    During the tests of the spacecraft electrical systems there is a need for simulators of individual parts of the spacecrafts, in particular, solar array simulators (SAS). One of the topologies of medium and high power SAS simulators has dual control of consumed power and contains series or parallel connected linear and switching regulators. This topology allows to provide wide bandwidth and high efficiency, but the range of the resistance change of periodically switched SAS load is limited to the value of the stabilized attribute. Nonlinear compensator (NC) allows to reduce the average feedback voltage of the switching regulator in case of periodic load switching, which, in turn, allows to increase the average value of the stabilized attribute. The describing function method provides a mathematical description of the NC electrical circuit, which allows to select parameters of NC that eliminate the excitation of self-oscillation based on the SAS load switching frequency range and to study the switching regulator stability.

  17. High power ac/dc variable R dynamic electrical load simulator

    NASA Technical Reports Server (NTRS)

    Joncas, K. P.

    1974-01-01

    A study program was undertaken to investigate various concepts and techniques for identifying and simulating both the steady-state and dynamic characteristics of electrical loads for use during integrated system test and evaluation. The development of hardware capable of providing the simulation capability is discussed. A general purpose simulator was developed with the capability of realizing a variety of models where element values were discretely variable. The different models, each corresponding to real spacecraft equipment, are set up manually for each case by suitable switching and patching. The models are capable of duplicating the dynamic and steady-state response of real loads at full power.

  18. Regulation control and energy management scheme for wireless power transfer

    SciTech Connect

    Miller, John M.

    2015-12-29

    Power transfer rate at a charging facility can be maximized by employing a feedback scheme. The state of charge (SOC) and temperature of the regenerative energy storage system (RESS) pack of a vehicle is monitored to determine the load due to the RESS pack. An optimal frequency that cancels the imaginary component of the input impedance for the output signal from a grid converter is calculated from the load of the RESS pack, and a frequency offset f* is made to the nominal frequency f.sub.0 of the grid converter output based on the resonance frequency of a magnetically coupled circuit. The optimal frequency can maximize the efficiency of the power transfer. Further, an optimal grid converter duty ratio d* can be derived from the charge rate of the RESS pack. The grid converter duty ratio d* regulates wireless power transfer (WPT) power level.

  19. Standard power regulator for the multi-mission modular spacecraft

    NASA Technical Reports Server (NTRS)

    Kichak, R. A.

    1979-01-01

    The Standard Power Regulator Unit (SPRU) which forms the central building block of the Modular Power Subsystem (MPS) for the Multi-mission Modular Spacecraft (MMS) is described. A functional description of the SPRU is presented, detailing key design features, operational characteristics, and internal redundancy as well as giving block and schematic diagrams for all major subassemblies. The description of a qualification test program consisting of ten sequences ranging from a physical examination of the unit to calculating vibration and sine sweep of power on shock tests is presented. The results showed that some significant anomalies were encountered but no catastrophic failures were indicated, although several power module failures were found due to overvoltage malfunctions of the solar array stimulator.

  20. Lamin A/C Acts as an Essential Factor in Mesenchymal Stem Cell Differentiation Through the Regulation of the Dynamics of the Wnt/β-Catenin Pathway.

    PubMed

    Bermeo, Sandra; Vidal, Christopher; Zhou, Hong; Duque, Gustavo

    2015-10-01

    Changes in the expression of lamin A/C, a fibrilar protein of the nuclear envelope, are associated with the cellular features of age-related bone loss. Reduced expression of lamin A/C inhibits osteoblastogenesis while facilitating adipogenic differentiation of mesenchymal stem cells (MSC) in vitro and in vivo. In this study we investigated the regulatory role that lamin A/C plays on the essential elements of the Wnt/β-catenin pathway, which are pivotal in MSC differentiation. Initially, we assessed the effect of lamin A/C gene (LMNA) overexpression on MSC differentiation while compared it to lamin A/C depleted MSC. Osteogenesis and gene expression of osteogenic factors were higher in LMNA-transfected MSC as compared to control. Conversely, adipogenesis and expression of adipogenic factors were significantly lower in LMNA transfected cells. Nuclear β-catenin was significantly higher (∼two fold) in MSC expressing higher levels of LMNA as compared to control with nuclear β-catenin levels being significantly lower (∼ -42%) in siRNA-treated MSC. Luciferase activity for β-catenin-mediated transcriptional activation was significantly higher in cells overexpressing LMNA. These data indicate that MSC overexpressing LMNA have higher osteogenic and lower adipogenic differentiation potential. In conclusion, our studies demonstrate that lamin A/C plays a significant role in the differentiation of both osteoblasts and adipocytes by regulating some of the elements of Wnt/β-catenin signaling during early MSC differentiation.

  1. Evolving Role of the Power Sector Regulator: A Clean Energy Regulators Initiative Report

    SciTech Connect

    Zinaman, O.; Miller, M.; Bazilian, M.

    2014-04-01

    This paper seeks to briefly characterize the evolving role of power sector regulation. Given current global dynamics, regulation of the power sector is undergoing dramatic changes. This transformation is being driven by various factors including technological advances and cost reductions in renewable energy, energy efficiency, and demand management; increasing air pollution and climate change concerns; and persistent pressure for ensuring sustainable economic development and increased access to energy services by the poor. These issues add to the already complex task of power sector regulation, of which the fundamental remit remains to objectively and transparently ensure least-cost service delivery at high quality. While no single regulatory task is trivial to undertake, it is the prioritization and harmonization of a multitude of objectives that exemplifies the essential challenge of power sector regulation. Evolving regulatory roles can be understood through the concept of existing objectives and an additional layer of emerging objectives. Following this categorization, we describe seven existing objectives of power sector regulators and nine emerging objectives, highlighting key challenges and outlining interdependencies. This essay serves as a preliminary installment in the Clean Energy Regulatory Initiative (CERI) series, and aims to lay the groundwork for subsequent reports and case studies that will explore these topics in more depth.

  2. Transgenic analysis reveals LeACS-1 as a positive regulator of ethylene-induced shikonin biosynthesis in Lithospermum erythrorhizon hairy roots.

    PubMed

    Fang, Rongjun; Wu, Fengyao; Zou, Ailan; Zhu, Yu; Zhao, Hua; Zhao, Hu; Liao, Yonghui; Tang, Ren-Jie; Yang, Tongyi; Pang, Yanjun; Wang, Xiaoming; Yang, Rongwu; Qi, Jinliang; Lu, Guihua; Yang, Yonghua

    2016-03-01

    The phytohormone ethylene (ET) is a crucial signaling molecule that induces the biosynthesis of shikonin and its derivatives in Lithospermum erythrorhizon shoot cultures. However, the molecular mechanism and the positive regulators involved in this physiological process are largely unknown. In this study, the function of LeACS-1, a key gene encoding the 1-aminocyclopropane-1-carboxylic acid synthase for ET biosynthesis in L. erythrorhizon hairy roots, was characterized by using overexpression and RNA interference (RNAi) strategies. The results showed that overexpression of LeACS-1 significantly increased endogenous ET concentration and shikonin production, consistent with the up-regulated genes involved in ET biosynthesis and transduction, as well as the genes related to shikonin biosynthesis. Conversely, RNAi of LeACS-1 effectively decreased endogenous ET concentration and shikonin production and down-regulated the expression level of above genes. Correlation analysis showed a significant positive linear relationship between ET concentration and shikonin production. All these results suggest that LeACS-1 acts as a positive regulator of ethylene-induced shikonin biosynthesis in L. erythrorhizon hairy roots. Our work not only gives new insights into the understanding of the relationship between ET and shikonin biosynthesis, but also provides an efficient genetic engineering target gene for secondary metabolite production in non-model plant L. erythrorhizon.

  3. RNA-seq Analysis Reveals That an ECF σ Factor, AcsS, Regulates Achromobactin Biosynthesis in Pseudomonas syringae pv. syringae B728a

    PubMed Central

    Greenwald, Jessica W.; Greenwald, Charles J.; Philmus, Benjamin J.; Begley, Tadhg P.; Gross, Dennis C.

    2012-01-01

    Iron is an essential micronutrient for Pseudomonas syringae pv. syringae strain B728a and many other microorganisms; therefore, B728a has evolved methods of iron acquirement including the use of iron-chelating siderophores. In this study an extracytoplasmic function (ECF) sigma factor, AcsS, encoded within the achromobactin gene cluster is shown to be a major regulator of genes involved in the biosynthesis and secretion of this siderophore. However, production of achromobactin was not completely abrogated in the deletion mutant, implying that other regulators may be involved such as PvdS, the sigma factor that regulates pyoverdine biosynthesis. RNA-seq analysis identified 287 genes that are differentially expressed between the AcsS deletion mutant and the wild type strain. These genes are involved in iron response, secretion, extracellular polysaccharide production, and cell motility. Thus, the transcriptome analysis supports a role for AcsS in the regulation of achromobactin production and the potential activity of both AcsS and achromobactin in the plant-associated lifestyle of strain B728a. PMID:22529937

  4. Implications of Carbon Regulation for Green Power Markets

    SciTech Connect

    Bird, Lori; Holt, Ed; Carroll, Ghita

    2007-04-01

    This paper examines the potential effects that emerging mandatory carbon markets have for voluntary markets for renewable energy, or green power markets. In an era of carbon regulation, green power markets will continue to play an important role because many consumers may be interested in supporting renewable energy development beyond what is supported through mandates or other types of policy support. The paper examines the extent to which GHG benefits motivate consumers to make voluntary renewable energy purchases and summarizes key issues emerging as a result of these overlapping markets, such as the implications of carbon regulation for renewable energy marketing claims, the demand for and price of renewable energy certificates (RECs), and the use of RECs in multiple markets (disaggregation of attributes). It describes carbon regulation programs under development in the Northeast and California, and how these might affect renewable energy markets in these regions, as well as the potential interaction between voluntary renewable energy markets and voluntary carbon markets, such as the Chicago Climate Exchange (CCX). It also briefly summarizes the experience in the European Union, where carbon is already regulated. Finally, the paper presents policy options for policymakers and regulators to consider in designing carbon policies to enable carbon markets and voluntary renewable energy markets to work together.

  5. Excision Patterns of Activator (Ac) and Dissociation (Ds) Elements in Zea Mays L.: Implications for the Regulation of Transposition

    PubMed Central

    Heinlein, M.

    1996-01-01

    The pattern of aleurone variegation of maize kernels carrying Ac and bz-m2(DI) as reporter allele for Ac activity depends on the dosage of both Ac and Ds. Alterations of Ac dosage can abolish Ds excision at certain times and allow it to occur at other times. wx-m7 and wx-m9 are different Ac insertions in the Waxy gene which have different dosage effects on Ds excision. Kernels, heterozygous for the two Ac alleles and being either wx-m7/wx-m7/wx-m9 or wx-m9/wx-m9/wx-m7 exhibit characteristic patterns of predominantly late excisions; this is in strong contrast to the pattern of early excisions present on wx-m7/wx-m7/wx-m7 homozygotes. This observation supports the hypothesis that the Ac alleles express different amounts of transposase (TPase) during development and that above a certain level of TPase transposition is inhibited. Furthermore, experimental results suggest that the frequency of Ac-induced events is influenced by the dosage and composition of the transactivated Ds or Ac allele. Thus, transposition frequency seems not to be exclusively determined in trans by the amount of active TPase, but also by specific cis-acting properties of the TPase substrate. PMID:8978069

  6. Down-regulation of a novel ABC transporter gene (Pxwhite) is associated with Cry1Ac resistance in the diamondback moth, Plutella xylostella (L.).

    PubMed

    Guo, Zhaojiang; Kang, Shi; Zhu, Xun; Xia, Jixing; Wu, Qingjun; Wang, Shaoli; Xie, Wen; Zhang, Youjun

    2015-04-01

    Biopesticides or transgenic crops based on Cry toxins from the soil bacterium Bacillus thuringiensis (Bt) effectively control agricultural insect pests. The sustainable use of Bt biopesticides and Bt crops is threatened, however, by the development of Cry resistance in the target pests. The diamondback moth, Plutella xylostella (L.), is the first pest that developed resistance to a Bt biopesticide in the field, and a recent study has shown that the resistance of P. xylostella to Cry1Ac is caused by a mutation in an ATP-binding cassette (ABC) transporter gene (ABCC2). In this study, we report that down-regulation of a novel ABC transporter gene from ABCG subfamily (Pxwhite) is associated with Cry1Ac resistance in P. xylostella. The full-length cDNA sequence of Pxwhite was cloned and analyzed. Spatial-temporal expression detection revealed that Pxwhite was expressed in all tissues and developmental stages, and highest expressed in Malpighian tubule tissue and in egg stage. Sequence variation analysis of Pxwhite indicated the absence of constant non-synonymous mutations between susceptible and resistant strains, whereas midgut transcript analysis showed that Pxwhite was remarkably reduced in all resistant strains and further reduced when larvae of the moderately resistant SZ-R strain were subjected to selection with Cry1Ac toxin. Furthermore, RNA interference (RNAi)-mediated suppression of Pxwhite gene expression significantly reduced larval susceptibility to Cry1Ac toxin, and genetic linkage analysis confirmed that down-regulation of Pxwhite gene is tightly linked to Cry1Ac resistance in P. xylostella. To our knowledge, this is the first report indicating that Pxwhite gene is involved in Cry1Ac resistance in P. xylostella.

  7. Expression and regulation of pear 1-aminocyclopropane-1-carboxylic acid synthase gene (PpACS1a) during fruit ripening, under salicylic acid and indole-3-acetic acid treatment, and in diseased fruit.

    PubMed

    Shi, Hai-Yan; Zhang, Yu-Xing

    2014-06-01

    In plants, the level of ethylene is determined by the activity of the key enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS). A gene encoding an ACC synthase protein was isolated from pear (Pyrus pyrifolia). This gene designated PpACS1a (GenBank accession no. KC632526) was 1488 bp in length with an open reading frame (ORF) encoding a protein of 495 amino acids that shared high similarity with other pear ACC synthase proteins. The PpACS1a was grouped into type-1 subfamily of plant ACS based on its conserved domain and phylogenetic status. Real-time quantitative PCR indicated that PpACS1a was differentially expressed in pear tissues and predominantly expressed in anthers. The expression signal of PpACS1a was also detected in fruit and leaves, but no signal was detected in shoots and petals. Furthermore, the PpACS1a expression was regulated during fruit ripening. In addition, the PpACS1a gene expression was regulated by salicylic acid (SA) and indole-3-acetic acid (IAA) in fruit. Moreover, the expression of the PpACS1a was up-regulated in diseased pear fruit. These results indicated that PpACS1a might be involved in fruit ripening and response to SA, IAA and disease.

  8. A putative positive feedback regulation mechanism in CsACS2 expression suggests a modified model for sex determination in cucumber (Cucumis sativus L.)

    PubMed Central

    Wang, Shu; Tao, Qianyi; Pan, Junsong; Si, Longting; Gong, Zhenhui; Cai, Run

    2012-01-01

    It is well established that the plant hormone ethylene plays a key role in cucumber sex determination. Since the unisexual control gene M was cloned and shown to encode an ethylene synthase, instead of an ethylene receptor, the ‘one-hormone hypothesis’, which was used to explain the cucumber sex phenotype, has been challenged. Here, the physiological function of CsACS2 (the gene encoded by the M locus) was studied using the transgenic tobacco system. The results indicated that overexpression of CsACS2 increased ethylene production in the tobacco plant, and the native cucumber promoter had no activity in transgenic tobacco (PM). However, when PM plants were treated with exogenous ethylene, CsACS2 expression could be detected. In cucumber, ethylene treatment could also induce transcription of CsACS2, while inhibition of ethylene action reduced the expression level. These findings suggest a positive feedback regulation mechanism for CsACS2, and a modified ‘one-hormone hypothesis’ for sex determination in cucumber is proposed. PMID:22577183

  9. A putative positive feedback regulation mechanism in CsACS2 expression suggests a modified model for sex determination in cucumber (Cucumis sativus L.).

    PubMed

    Li, Zheng; Wang, Shu; Tao, Qianyi; Pan, Junsong; Si, Longting; Gong, Zhenhui; Cai, Run

    2012-07-01

    It is well established that the plant hormone ethylene plays a key role in cucumber sex determination. Since the unisexual control gene M was cloned and shown to encode an ethylene synthase, instead of an ethylene receptor, the 'one-hormone hypothesis', which was used to explain the cucumber sex phenotype, has been challenged. Here, the physiological function of CsACS2 (the gene encoded by the M locus) was studied using the transgenic tobacco system. The results indicated that overexpression of CsACS2 increased ethylene production in the tobacco plant, and the native cucumber promoter had no activity in transgenic tobacco (PM). However, when PM plants were treated with exogenous ethylene, CsACS2 expression could be detected. In cucumber, ethylene treatment could also induce transcription of CsACS2, while inhibition of ethylene action reduced the expression level. These findings suggest a positive feedback regulation mechanism for CsACS2, and a modified 'one-hormone hypothesis' for sex determination in cucumber is proposed.

  10. The structure of C290A:C393A Aurora A provides structural insights into kinase regulation

    PubMed Central

    Burgess, Selena G.; Bayliss, Richard

    2015-01-01

    Aurora A is a Ser/Thr protein kinase that functions in cell-cycle regulation and is implicated in cancer development. During mitosis, Aurora A is activated by autophosphorylation on its activation loop at Thr288. The Aurora A catalytic domain (amino acids 122–403) expressed in Escherichia coli autophosphorylates on two activation-loop threonine residues (Thr288 and Thr287), whereas a C290A,C393A double point mutant of the Aurora A catalytic domain autophosphorylates only on Thr288. The structure of the complex of this mutant with ADP and magnesium was determined to 2.1 Å resolution using molecular replacement. This is an improvement on the existing 2.75 Å resolution structure of the equivalent wild-type complex. The structure confirms that single phosphorylation of the activation loop on Thr288 is insufficient to stabilize a ‘fully active’ conformation of the activation loop in the absence of binding to TPX2. PMID:25760707

  11. 75 FR 29531 - Frequency Regulation Compensation in the Organized Wholesale Power Markets; Supplemental Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-26

    ...] Frequency Regulation Compensation in the Organized Wholesale Power Markets; Supplemental Notice of Technical... conference will provide a forum to consider issues related to frequency regulation compensation in...

  12. Revised seismic and geologic siting regulations for nuclear power plants

    SciTech Connect

    Murphy, A.J.; Chokshi, N.C.

    1997-02-01

    The primary regulatory basis governing the seismic design of nuclear power plants is contained in Appendix A to Part 50, General Design Criteria for Nuclear Power Plants, of Title 10 of the Code of Federal Regulations (CFR). General Design Criteria (GDC) 2 defines requirements for design bases for protection against natural phenomena. GDC 2 states the performance criterion that {open_quotes}Structures, systems, and components important to safety shall be designed to withstand the effects of natural phenomena such as earthquakes, . . . without loss of capability to perform their safety functions. . .{close_quotes}. Appendix A to Part 100, Seismic and Geologic Siting Criteria for Nuclear Power Plants, has been the principal document which provided detailed criteria to evaluate the suitability of proposed sites and suitability of the plant design basis established in consideration of the seismic and geologic characteristics of the proposed sites. Appendix A defines required seismological and geological investigations and requirements for other design conditions such as soil stability, slope stability, and seismically induced floods and water waves, and requirements for seismic instrumentation. The NRC staff is in the process of revising Appendix A. The NRC has recently revised seismic siting and design regulations for future applications. These revisions are discussed in detail in this paper.

  13. DC switching regulated power supply for driving an inductive load

    DOEpatents

    Dyer, George R.

    1986-01-01

    A power supply for driving an inductive load current from a dc power supply hrough a regulator circuit including a bridge arrangement of diodes and switching transistors controlled by a servo controller which regulates switching in response to the load current to maintain a selected load current. First and second opposite legs of the bridge are formed by first and second parallel-connected transistor arrays, respectively, while the third and fourth legs of the bridge are formed by appropriately connected first and second parallel connected diode arrays, respectively. The regulator may be operated in three "stages" or modes: (1) For current runup in the load, both first and second transistor switch arrays are turned "on" and current is supplied to the load through both transistor arrays. (2) When load current reaches the desired level, the first switch is turned "off", and load current "flywheels" through the second switch array and the fourth leg diode array connecting the second switch array in series with the load. Current is maintained by alternating between modes 1 and 2 at a suitable duty cycle and switching rate set by the controller. (3) Rapid current rundown is accomplished by turning both switch arrays "off", allowing load current to be dumped back into the source through the third and fourth diode arrays connecting the source in series opposition with the load to recover energy from the inductive load. The three operating states are controlled automatically by the controller.

  14. DC switching regulated power supply for driving an inductive load

    DOEpatents

    Dyer, G.R.

    1983-11-29

    A dc switching regulated power supply for driving an inductive load is provided. The regulator basic circuit is a bridge arrangement of diodes and transistors. First and second opposite legs of the bridge are formed by first and second parallel-connected transistor arrays, respectively, while the third and fourth legs of the bridge are formed by appropriately connected first and second parallel connected diode arrays, respectively. A dc power supply is connected to the input of the bridge and the output is connected to the load. A servo controller is provided to control the switching rate of the transistors to maintain a desired current to the load. The regulator may be operated in three stages or modes: (1) for current runup in the load, both first and second transistor switch arrays are turned on and current is supplied to the load through both transistor arrays. (2) When load current reaches the desired level, the first switch is turned off, and load current flywheels through the second switch array and the fourth leg diode array connecting the second switch array in series with the load. Current is maintained by alternating between modes 1 and 2 at a suitable duty cycle and switching rate set by the controller. (3) Rapid current rundown is accomplished by turning both switch arrays off, allowing load current to be dumped back into the source through the third and fourth diode arrays connecting the source in series opposition with the load to recover energy from the inductive load.

  15. 75 FR 30812 - Frequency Regulation Compensation in the Organized Wholesale Power Markets; Further Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-02

    ... Energy Regulatory Commission Frequency Regulation Compensation in the Organized Wholesale Power Markets... of Proposed Rulemaking on Frequency Regulation Compensation in the Organized Wholesale Power Markets, as previously announced.\\1\\ \\1\\ Notice of Technical Conference re Frequency Compensation in...

  16. 75 FR 31430 - Frequency Regulation Compensation in the Organized Wholesale Power Markets; Notice Establishing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-03

    ... Energy Regulatory Commission Frequency Regulation Compensation in the Organized Wholesale Power Markets... technical conference regarding frequency regulation in the organized wholesale power markets, as previously announced.\\1\\ \\1\\ Notice of Technical Conference re Frequency Compensation in the Organized Wholesale...

  17. Atorvastatin Alleviates Experimental Diabetic Cardiomyopathy by Regulating the GSK-3β-PP2Ac-NF-κB Signaling Axis

    PubMed Central

    Wu, Wen; Luo, Jie; Ye, Peng; Chen, Shao-liang; Hu, Zuo-ying

    2016-01-01

    Recent studies reported that atorvastatin (ATOR) alleviated progression of experimental diabetic cardiomyopathy (DCM), possibly by protecting against apoptosis. However, the underlying mechanisms of this protective effect remain unclear. Therefore, our study investigated the role of the glycogen synthase kinase (GSK)-3β-protein phosphatase 2A(PP2A)-NF-κB signaling pathway in the anti-apoptotic and cardioprotective effects of ATOR on cardiomyocytes cultured in high glucose (HG) and in DCM. Our results showed that, in HG-cultured cardiomyocytes, phosphorylation of GSK-3β was decreased, while that of the PP2A catalytic subunit C (PP2Ac) and IKK/IкBα was increased, followed by NF-кB nuclear translocation and apoptosis. IKK/IкBα phosphorylation and NF-кB nuclear translocation were also increased by treatment of cells with okadaic acid (OA), a selective PP2A inhibitor, or by silencing PP2Ac expression. The opposite results were obtained by silencing GSK-3β expression, which resulted in PP2Ac activation. Furthermore, IKK/IкBα phosphorylation and NF-кB nuclear translocation were markedly inhibited and apoptosis attenuated in cells treated with ATOR. These effects occurred through inactivation of GSK-3β and subsequent activation of PP2Ac. They were abolished by treatment of cells with OA or PP2Ac siRNA. In mice with type 1 diabetes mellitus, treatment with ATOR, at 10 mg-kg−1-d−1, significantly suppressed GSK-3β activation, IKK/IкBα phosphorylation, NF-кB nuclear translocation and caspase-3 activation, while also activating PP2Ac. Finally, improvements in histological abnormalities, fibrosis, apoptosis and cardiac dysfunction were observed in diabetic mice treated with ATOR. These findings demonstrated that ATOR protected against HG-induced apoptosis in cardiomyocytes and alleviated experimental DCM by regulating the GSK-3β-PP2A-NF-κB signaling pathway. PMID:27851811

  18. Fundamental Understanding of the Impact High Pulsed Power Loading has on a MicroGrid’s DC or AC Bus

    DTIC Science & Technology

    2013-06-12

    Seamless integration of distributed/renewable energy into a smart MicroGrid architecture is a hot topic of research for both public and defense...applications. It is the DoD’s intention to develop a more cost efficient and reliable power architecture on the battlefield. A smart MicroGrid ...dedicated power supplies. The impact this type of loading has on the central DC or AC bus of a MicroGrid must be studied and it was the intent of

  19. Digital regulation of a phase controlled power converter

    SciTech Connect

    Schultheiss, C.; Haque, T.

    1995-12-01

    The Relativistic Heavy Ion Collider, now in construction at Brookhaven National Laboratory, will use phase controlled power converters for the main dipole and quadrupole magnet strings. The rectifiers in these power supplies will be controlled by a digital regulator based on the TI 320C30 Digital Signal Processor (DSP). The DSP implements the current loop, the voltage loop, and a system to actively reduce the sub-harmonic ripple components. Digital firing circuits consisting of a phase locked lop and counters are used to fire the SCRs. Corrections for the sub-harmonic reduction are calculated by the DSP and stored in registers in the firing circuit. These corrections are added in hardware, to the over-all firing count provided by the DSP. the resultant count is compared to a reference counter to fire the SCRs. This combination of a digital control system and the digital firing circuits allows the correction of the sub-harmonics in a real-time sense. A prototype of the regulator has been constructed, and the preliminary testing indicates a sub-harmonic reduction of 60 dB.

  20. Electric utility power plant choice under investment regulation

    SciTech Connect

    Rothwell, G.S.

    1985-01-01

    Economists have examined electric utility behavior under an allowed rate of return (ARoR), but little attention has been given to the regulation of generation technology choice. Two financial methods for regulating this investment decision are Allowance for Funds Used During Construction (AFUDC) and Construction Work in Progress (CWIP). The switch from AFUDC to CWIP by federal and state commissions has sparked a national debate. One issue addressed in this study is whether AFUDC or CWIP influenced technology choice. The first chapter reviews policy and compares the present value of returns to the firm under AFUDC with returns under CWIP. Chapter 2 discusses previous studied of electric utility behavior. In the third chapter, a general model is developed in which profit and revenue maximization, and cost minimization, are nested. It incorporates cost uncertainty, as well as AFUDC and CWIP. Chapter 4 estimates cost functions for coal and nuclear capacity with data on 350 units completed between 1965 and 1980. These estimates are used to forecast firm expectations on the mean and variance of power plant costs. Results suggest that while rate-of-return and investment regulation may not have had a great influence on plant choice, policies that change perceived cost uncertainties will have a significant impact on firm behavior.

  1. Down-regulation of the Lamin A/C in neuroblastoma triggers the expansion of tumor initiating cells.

    PubMed

    Nardella, Marta; Guglielmi, Loredana; Musa, Carla; Iannetti, Ilaria; Maresca, Giovanna; Amendola, Donatella; Porru, Manuela; Carico, Elisabetta; Sessa, Giuseppe; Camerlingo, Rosalba; Dominici, Carlo; Megiorni, Francesca; Milan, Marika; Bearzi, Claudia; Rizzi, Roberto; Pirozzi, Giuseppe; Leonetti, Carlo; Bucci, Barbara; Mercanti, Delio; Felsani, Armando; D'Agnano, Igea

    2015-10-20

    Tumor-initiating cells constitute a population within a tumor mass that shares properties with normal stem cells and is considered responsible for therapy failure in many cancers. We have previously demonstrated that knockdown of the nuclear envelope component Lamin A/C in human neuroblastoma cells inhibits retinoic acid-mediated differentiation and results in a more aggressive phenotype. In addition, Lamin A/C is often lost in advanced tumors and changes in the nuclear envelope composition occur during tumor progression. Based on our previous data and considering that Lamin A/C is expressed in differentiated tissues, we hypothesize that the lack of Lamin A/C could predispose cells toward a stem-like phenotype, thus influencing the development of tumor-initiating cells in neuroblastoma. This paper demonstrates that knockdown of Lamin A/C triggers the development of a tumor-initiating cell population with self-renewing features in human neuroblastoma cells. We also demonstrates that the development of TICs is due to an increased expression of MYCN gene and that in neuroblastoma exists an inverse relationship between LMNA and MYCN expression.

  2. Satellite Power System (SPS). State and local regulations as applied to satellite power system microwave receiving antenna facilities

    NASA Technical Reports Server (NTRS)

    Kotin, A. D.

    1978-01-01

    State and local regulation of power plant construction and operation of solar power satellite (SPS) receiving stations is presented. Each receiving antenna station occupies a land area 100-200 km square, receives microwave transmissions from the solar power satellite, and converts them into electricity for transmission to the power grid. The long lead time associated with the SPS and the changing status of state and local regulation dictated emphasis on: generic classification of the types of regulation, and identification of regulatory vectors which affect rectenna facilities.

  3. Interleukin-13-induced MUC5AC expression is regulated by a PI3K–NFAT3 pathway in mouse tracheal epithelial cells

    SciTech Connect

    Yan, Fugui; Li, Wen; Zhou, Hongbin; Wu, Yinfang; Ying, Songmin; Chen, Zhihua; Shen, Huahao

    2014-03-28

    Highlights: • IL-13 specifically induced NFAT3 activation in mouse tracheal epithelial cells. • CsA and LY294002 significantly blocked IL-13-induced MUC5AC production. • The PI3K–NFAT3 pathway is positively involved in IL-13-induced MUC5AC production. - Abstract: Interleukin-13 (IL-13) plays a critical role in asthma mucus overproduction, while the mechanisms underlying this process are not fully elucidated. Previous studies showed that nuclear factor of activated T cells (NFAT) is involved in the pathogenesis of asthma, but whether it can directly regulate IL-13-induced mucus (particularly MUC5AC) production is still not clear. Here we showed that IL-13 specifically induced NFAT3 activation through promoting its dephosphorylation in air–liquid interface (ALI) cultures of mouse tracheal epithelial cells (mTECs). Furthermore, both Cyclosporin A (CsA, a specific NFAT inhibitor) and LY294002 (a Phosphoinositide 3-kinase (PI3K) inhibitor) significantly blocked IL-13-induced MUC5AC mRNA and protein production through the inhibition of NFAT3 activity. We also confirmed that CsA could not influence the forkhead Box A2 (Foxa2) and mouse calcium dependent chloride channel 3 (mClca3) expression in IL-13-induced MUC5AC production, which both are known to be important in IL-13-stimulated mucus expression. Our study is the first to demonstrate that the PI3K–NFAT3 pathway is positively involved in IL-13-induced mucus production, and provided novel insights into the molecular mechanism of asthma mucus hypersecretion.

  4. 77 FR 35671 - Conformed Power Marketing Criteria or Regulations for the Boulder Canyon Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-14

    ... Area Power Administration Conformed Power Marketing Criteria or Regulations for the Boulder Canyon Project AGENCY: Western Area Power Administration, DOE. ACTION: Conformance of power marketing criteria in... (Western), a Federal power marketing agency of the Department of Energy (DOE), is modifying Part C of...

  5. Photovoltaic-powered regulated cathodic-protection system

    NASA Astrophysics Data System (ADS)

    Anis, Wagdy R.; Alfons, Hany A.

    The objective of a cathodic protection system is to protect metallic structures against corrosion. To achieve this, a sacrificial anode is connected to the protected structure (which acts as a cathode) through a d.c. power supply. To stop the corrosion, the protected structure requires a constant current. The current is determined by the metal and area of the structure, as well as the surrounding medium. The major difficulty in achieving a constant current is the variation in the resistivity of the surrounding medium that is caused by changes in the climatic conditions. Conventional cathodic-protection systems resolve this problem by manual adjustment of the d.c. voltage periodically to obtain a constant current. Such adjustment depends on the experience of the technician and the accuracy of the measuring equipment. Moreover if the interval between successive adjustments is relative long, the corrosion could become excessive. To overcome such difficulties, an automatically regulated system has been developed. The proposed system senses variations is the resistivity of the surrounding medium and adjusts the d.c. voltage accordingly so that the current is kept constant at the required level. The design of a solar photovoltaic system to supply the required d.c. power is discussed in this communication.

  6. Common station system for voltage and reactive power regulation at the Mosenergo TETs-27 heating and electric power plant

    SciTech Connect

    Krasnova, M. E.

    2009-05-15

    The system for common station regulation of the voltage and reactive power at the Mosenergo TETs-27 heating and electric power plant is described briefly. Features of the algorithms for this system, which uses programs and instrumentation from the automatic control system for the electrical equipment in the 450 MW power generation unit No. 3, are examined.

  7. Observer-based higher order sliding mode control of power factor in three-phase AC/DC converter for hybrid electric vehicle applications

    NASA Astrophysics Data System (ADS)

    Liu, Jianxing; Laghrouche, Salah; Wack, Maxime

    2014-06-01

    In this paper, a full-bridge boost power converter topology is studied for power factor control, using output higher order sliding mode control. The AC/DC converters are used for charging the battery and super-capacitor in hybrid electric vehicles from the utility. The proposed control forces the input currents to track the desired values, which can control the output voltage while keeping the power factor close to one. Super-twisting sliding mode observer is employed to estimate the input currents and load resistance only from the measurement of output voltage. Lyapunov analysis shows the asymptotic convergence of the closed-loop system to zero. Multi-rate simulation illustrates the effectiveness and robustness of the proposed controller in the presence of measurement noise.

  8. Voltage regulator dissipates minimal power and functions as a voltage divider

    NASA Technical Reports Server (NTRS)

    Hester, H. B.

    1971-01-01

    Regulator requires minimum amount of power for voltage division and it is not required continuously. The only power loss, except for regulating purposes, is that needed to provide for imbalances in load current requirements. For balanced loads, only leakage current flows through regulating transistors.

  9. Tevatron AC dipole system

    SciTech Connect

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

    2007-06-01

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

  10. Examining the Variability of Wind Power Output in the Regulation Time Frame: Preprint

    SciTech Connect

    Hodge, B. M.; Shedd, S.; Florita, A.

    2012-08-01

    This work examines the distribution of changes in wind power for different time scales in the regulation time frame as well as the correlation of changes in power output for individual wind turbines in a wind plant.

  11. The shunt-LDO regulator to power the upgraded ATLAS pixel detector

    NASA Astrophysics Data System (ADS)

    Gonella, L.; Barbero, M.; Hügging, F.; Krüger, H.; Wermes, N.

    2012-01-01

    The shunt-LDO regulator is a new regulator concept which combines a shunt and a Low Drop-Out (LDO) regulator. Designed as an improved shunt regulator to match the needs of serially powered detector systems, it can also be used as a pure LDO regulator for general application in powering schemes requiring linear regulation. The flexibility of the design makes the shunt-LDO regulator a good candidate for use in the powering schemes envisaged for the upgrades of the ATLAS pixel detector. Two shunt-LDO regulators integrated in the prototype of the next ATLAS pixel front-end chip, the FE-I4A, are used to demonstrate the feasibility of the proposed powering solutions.

  12. 75 FR 23759 - Frequency Regulation Compensation in the Organized Wholesale Power Markets; Notice of Technical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-04

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Frequency Regulation Compensation in the Organized Wholesale Power... technical conference to elicit input on issues pertaining to Frequency Regulation Compensation in the...

  13. Experimental study of loss mechanisms of AgAu/PbBi-2223 tapes with twisted filaments under perpendicular AC magnetic fields at power frequencies

    NASA Astrophysics Data System (ADS)

    Martínez, E.; Yang, Y.; Beduz, C.; Huang, Y. B.

    2000-05-01

    AC losses under perpendicular AC fields have been measured at 77 K and power frequencies for multifilamentary AgAu (10 wt.%)/Bi-2223 tapes with filaments twisted at different pitches. Using simultaneous measurements of the first and higher harmonics of the voltage induced in the pick-up coil, the main loss contributions (superconductor and coupling current losses) have been obtained separately. At power frequencies, twisting produces the desired uncoupling of the filaments at fields lower than the coupling field, which has also been determined experimentally. In the uncoupled-filament regime, the superconductor losses are reduced strongly with respect to the untwisted tapes. The reduction of the total loss with twisting is also observed. However, due to the important contribution of the coupling current losses for this field orientation, a very small pitch (<5 mm) is necessary for a considerably lower loss than that of untwisted tapes. The dependence of the coupling field and coupling current losses on the twist pitch has been analysed and compared with the theoretical predictions.

  14. Review of nuclear power plant offsite power source reliability and related recommended changes to the NRC rules and regulations

    SciTech Connect

    Battle, R.E.; Clark, F.H.; Reddoch, T.W.

    1980-05-01

    The NRC has stated its concern about the reliability of the offsite power system as the preferred emergency source and about the possible damage to a pressurized water reactor (PWR) that could result from a rapid decay of power grid frequency. ORNL contracted with NRC to provide technical assistance to establish criteria that can be used to evaluate the offsite power system for the licensing of a nuclear power plant. The results of many of the studies for this contract are recommendations to assess and control the power grid during operation. This is because most of the NRC regulations pertaining to the offsite power system are related to the design of the power grid, and we believe that additional emphasis on monitoring the power grid operation will improve the reliability of the nuclear plant offsite power supply. 46 refs., 10 figs.

  15. Composite rod insulators for ac power lines; Electrical performance of various designs at a coastal testing station

    SciTech Connect

    Houlgate, R.G.; Swift, D.A. )

    1990-10-01

    The electrical performance of thirty-six composite insulators - of four commercial types for each AC system level of 34.5 kV, 230 kV and 500 kV - has been determined at the CEGB insulator testing station, Brighton, England. The weathershed materials were epoxy-resin, ethylene propylene rubber and silicone rubber; half of the 230 kV insulators had no stress rings. Surface leakage current was recorded for surge levels of 25 mA, 150 mA and 500 mA; a special technique was developed to obtain the flashover statistics of the 500 kV insulators, thereby enabling performance of the composite insulator to be quantified relative to that of a string of cap and pin porcelain insulators of anti-fog design, the deterioration of the insulators was observed by making regular visual inspections. The practical consequences of the findings and the causes of the degradation are discussed.

  16. Antiapoptotic activity of Akt is down-regulated by Ca2+ in myocardiac H9c2 cells. Evidence of Ca(2+)-dependent regulation of protein phosphatase 2Ac.

    PubMed

    Yasuoka, Chie; Ihara, Yoshito; Ikeda, Satoshi; Miyahara, Yoshiyuki; Kondo, Takahito; Kohno, Shigeru

    2004-12-03

    Cell survival signaling of the Akt/protein kinase B pathway was influenced by a change in the cytoplasmic free calcium concentration ([Ca2+]i) for over 2 h via the regulation of a Ser/Thr phosphatase, protein phosphatase 2Ac (PP2Ac), in rat myocardiac H9c2 cells. Akt was down-regulated when [Ca2+]i was elevated by thapsigargin, an inhibitor of the endoplasmic reticulum Ca(2+)-ATPase, but was up-regulated when it was suppressed by 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl)ester (BAPTA-AM), a cell permeable Ca2+ chelator. The inactivation of Akt was well correlated with the susceptibility to oxidant-induced apoptosis in H9c2 cells. To investigate the mechanism of the Ca(2+)-dependent regulation of Akt via the regulation of PP2A, we examined the transcriptional regulation of PP2Acalpha in H9c2 cells with Ca2+ modulators. Transcription of the PP2Acalpha gene was increased by thapsigargin but decreased by BAPTA-AM. The promoter activity was examined and the cAMP response element (CRE) was found responsible for the Ca(2+)-dependent regulation of PP2Acalpha. Furthermore, phosphorylation of CRE-binding protein increased with thapsigargin but decreased with BAPTA-AM. A long term change of [Ca2+]i regulates PP2Acalpha gene transcription via CRE, resulting in a change in the activation status of Akt leading to an altered susceptibility to apoptosis.

  17. Berberine ameliorates renal injury by regulating G proteins-AC- cAMP signaling in diabetic rats with nephropathy.

    PubMed

    Tang, Li Qin; Wang, Feng Ling; Zhu, Ling Na; Lv, Fei; Liu, Sheng; Zhang, Shan Tang

    2013-06-01

    Diabetic nephropathy (DN) is a progressive kidney disease that is caused by injury to glomerulus and glomerular mesangial cells (MCs) proliferation play a critical role in the pathogenesis of DN. The current studies were undertaken to investigate the protective effects and the possible molecular mechanism of berberine on streptozotocin (STZ)-induced DN rats. Male Wistar rats were randomly assigned to normal control and DN groups of comparable age. Three DN groups received 50, 100 and 200 mg/kg of berberine for 8 weeks via daily intragastrically, respectively. The G proteins-adenylyl cyclase (AC)-cAMP signaling pathway and glomerular MCs proliferation were examined in STZ-induced diabetic rat kidney. Enhanced MCs proliferation and remarkable renal injury were concomitant with activation of Gαi and inhibition of Gαs and cAMP in DN model group. Berberine treatment for 8 weeks abolished the above changes by upregulating the expression of Gαs protein and downregulating the expression of Gαi protein, increasing cAMP level, and inhibiting MCs proliferation compared with model group. Taken together, for the first time, these results demonstrated that berberine can relieve renal injury in DN rats through mediating G proteins-AC-cAMP signaling pathway and inhibiting the abnormal proliferation of MCs by increasing cAMP level, suggesting that berberine could be a potential therapeutic agent for the treatment of DN.

  18. AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT XVII, LEARNING ABOUT AC GENERATOR (ALTERNATOR) PRINCIPLES (PART II).

    ERIC Educational Resources Information Center

    Minnesota State Dept. of Education, St. Paul. Div. of Vocational and Technical Education.

    THIS MODULE OF A 25-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATING PRINCIPLES AND THE SERVICING AND TESTING PROCEDURES FOR ALTERNATING CURRENT (AC) GENERATORS AND REGULATORS USED ON DIESEL POWERED EQUIPMENT. TOPICS ARE REVIEW OF ALTERNATOR PRINCIPLES, ALTERNATOR SERVICING AND TESTING, ALTERNATOR REGULATOR OPERATING…

  19. Power fluctuations smoothing and regulations in wind turbine generator systems

    NASA Astrophysics Data System (ADS)

    Babazadehrokni, Hamed

    Wind is one of the most popular renewable energy sources and it has the potential to become the biggest energy source in future. Since the wind does not always blow constantly, the output wind power is not constant which may make some problem for the power grid. According to the grid code which is set by independent system operator, ISO, wind turbine generator systems need to follow some standards such as the predetermined acceptable power fluctuations. In order to smooth the output powers, the energy storage system and some power electronics modules are employed. The utilized power electronics modules in the wind turbine system can pursue many different goals, such as maintaining the voltage stability, frequency stability, providing the available and predetermined output active and reactive power. On the other side, the energy storage system can help achieving some of these goals but its main job is to store the extra energy when not needed and release the stored energy when needed. The energy storage system can be designed in different sizes, material and also combination of different energy storage systems (hybrid designs). Combination of power electronics devises and also energy storage system helps the wind turbine systems to smooth the output power according to the provided standards. In addition prediction of wind speed may improve the performance of wind turbine generator systems. In this research study all these three topics are studied and the obtained results are written in 10 papers which 7 of them are published and three of them are under process.

  20. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., low power, and booster stations. 74.780 Section 74.780 Telecommunication FEDERAL COMMUNICATIONS... PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.780 Broadcast regulations applicable to translators, low power, and booster stations. The following rules are applicable...

  1. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., low power, and booster stations. 74.780 Section 74.780 Telecommunication FEDERAL COMMUNICATIONS... PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.780 Broadcast regulations applicable to translators, low power, and booster stations. The following rules are applicable...

  2. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., low power, and booster stations. 74.780 Section 74.780 Telecommunication FEDERAL COMMUNICATIONS... PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.780 Broadcast regulations applicable to translators, low power, and booster stations. The following rules are applicable...

  3. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., low power, and booster stations. 74.780 Section 74.780 Telecommunication FEDERAL COMMUNICATIONS... PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.780 Broadcast regulations applicable to translators, low power, and booster stations. The following rules are applicable...

  4. Compensation for Harmonic Currents and Reactive Power in Wind Power Generation System using PWM Inverter

    NASA Astrophysics Data System (ADS)

    Shinohara, Katsuji; Shinhatsubo, Kurato; Iimori, Kenichi; Yamamoto, Kichiro; Saruban, Takamichi; Yamaemori, Takahiro

    In recent year, consciousness of environmental problems is enhancing, and the price of the electric power purchased by an electric power company is established expensive for the power plant utilizing the natural energy. So, the introduction of the wind power generation is promoted in Japan. Generally, squirrel-cage induction machines are widely used as a generator in wind power generation system because of its small size, lightweight and low-cost. However, the induction machines do not have a source of excitation. Thus, it causes the inrush currents and the instantaneous voltage drop when the generator is directly connected to a power grid. To reduce the inrush currents, an AC power regulator is used. Wind power generations are frequently connected to and disconnected from the power grid. However, when the inrush currents are reduced, harmonic currents are caused by phase control of the AC power regulator. And the phase control of AC power regulator cannot control the power factor. Therefore, we propose the use of the AC power regulator to compensate for the harmonic currents and reactive power in the wind power generation system, and demonstrate the validity of its system by simulated and experimental results.

  5. A New Design Method of AC Filter for Static Var Compensator

    NASA Astrophysics Data System (ADS)

    Tamura, Yuji; Irokawa, Shoichi; Takeda, Hideo; Takagi, Kikuo; Noro, Yasuhiro; Ametani, Akihiro

    A new approach of the AC filter design for the SVC (Static Var Compensator) is proposed in this paper. When the SVC consists of TCR(s) (Thyristor Controlled Reactor(s)) or TCT(s) (Thyristor Controlled Transformer(s)) and the AC filter(s), it is required to design AC filter(s) carefully to meet regulation level of harmonic voltage and current at the connection point of the SVC. In general, the AC filter design may require many iterative calculations of the harmonic performance by changing electrical parameters of the AC filter until all the harmonic voltage and current performances at the connection point of the SVC meet the regulation level on various conditions in terms of the filter de-tuning cases and the AC power system conditions. In this respect a new AC filter design approach is proposed, which is innovative on evaluation method of the performance to predetermine the permissible range of the AC filter harmonic impedance on the complex plane. By using this method, the iterations of the calculation can be reduced and it enables more efficient process of the design providing clear accountability of the decision of AC filter parameters.

  6. Evaluation Of Different Power Conditioning Options For Stirling Generators

    NASA Astrophysics Data System (ADS)

    Garrigos, A.; Blanes, J. M.; Carrasco, J. A.; Maset, E.; Montalban, G.; Ejea, J.; Ferreres, A.; Sanchis, E.

    2011-10-01

    Free-piston Stirling engines are an interesting alternative for electrical power systems, especially in deep space missions where photovoltaic systems are not feasible. This kind of power generators contains two main parts, the Stirling machine and the linear alternator that converts the mechanical energy from the piston movement to electrical energy. Since the generated power is in AC form, several aspects should be assessed to use such kind of generators in a spacecraft power system: AC/DC topologies, power factor correction, power regulation techniques, integration into the power system, etc. This paper details power generator operation and explores different power conversion approaches.

  7. ac bidirectional motor controller

    NASA Technical Reports Server (NTRS)

    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.

  8. Invoking the Power of Thrombospondins: Regulation of Thrombospondins Expression

    PubMed Central

    Stenina-Adognravi, Olga

    2014-01-01

    Increasing evidence suggests critical functions of thrombospondins (TSPs) in a variety of physiological and pathological processes. With the growing understanding of the importance of these matricellular proteins, the need to understand the mechanisms of regulation of their expression and potential approaches to modulate their levels is also increasing. The regulation of TSPs expression is multi-leveled, cell- and tissue-specific, and very precise. However, the knowledge of mechanisms modulating the levels of TSPs is fragmented and incomplete. This review discusses the known mechanisms of regulation of TSPs levels and the gaps in our knowledge that prevent us from developing strategies to modulate the expression of these physiologically important proteins. PMID:24582666

  9. Design of an Adaptive Power Regulation Mechanism and a Nozzle for a Hydroelectric Power Plant Turbine Test Rig

    NASA Astrophysics Data System (ADS)

    Mert, Burak; Aytac, Zeynep; Tascioglu, Yigit; Celebioglu, Kutay; Aradag, Selin; ETU Hydro Research Center Team

    2014-11-01

    This study deals with the design of a power regulation mechanism for a Hydroelectric Power Plant (HEPP) model turbine test system which is designed to test Francis type hydroturbines up to 2 MW power with varying head and flow(discharge) values. Unlike the tailor made regulation mechanisms of full-sized, functional HEPPs; the design for the test system must be easily adapted to various turbines that are to be tested. In order to achieve this adaptability, a dynamic simulation model is constructed in MATLAB/Simulink SimMechanics. This model acquires geometric data and hydraulic loading data of the regulation system from Autodesk Inventor CAD models and Computational Fluid Dynamics (CFD) analysis respectively. The dynamic model is explained and case studies of two different HEPPs are performed for validation. CFD aided design of the turbine guide vanes, which is used as input for the dynamic model, is also presented. This research is financially supported by Turkish Ministry of Development.

  10. Modeling and Compensation Design for a Power Hardware-in-the-Loop Simulation of an AC Distribution System

    SciTech Connect

    Ainsworth, Nathan; Hariri, Ali; Prabakar, Kumaraguru; Pratt, Annabelle; Baggu, Murali

    2016-11-21

    Power hardware-in-the-loop (PHIL) simulation, where actual hardware under text is coupled with a real-time digital model in closed loop, is a powerful tool for analyzing new methods of control for emerging distributed power systems. However, without careful design and compensation of the interface between the simulated and actual systems, PHIL simulations may exhibit instability and modeling inaccuracies. This paper addresses issues that arise in the PHIL simulation of a hardware battery inverter interfaced with a simulated distribution feeder. Both the stability and accuracy issues are modeled and characterized, and a methodology for design of PHIL interface compensation to ensure stability and accuracy is presented. The stability and accuracy of the resulting compensated PHIL simulation is then shown by experiment.

  11. Voltage regulator for battery power source. [using a bipolar transistor

    NASA Technical Reports Server (NTRS)

    Black, J. M. (Inventor)

    1979-01-01

    A bipolar transistor in series with the battery as the control element also in series with a zener diode and a resistor is used to maintain a predetermined voltage until the battery voltage decays to very nearly the predetermined voltage. A field effect transistor between the base of the bipolar transistor and a junction between the zener diode and resistor regulates base current of the bipolar transistor, thereby regulating the conductivity of the bipolar transistor for control of the output voltage.

  12. Differential basal-to-apical accessibility of lamin A/C epitopes in the nuclear lamina regulated by changes in cytoskeletal tension

    NASA Astrophysics Data System (ADS)

    Ihalainen, Teemu O.; Aires, Lina; Herzog, Florian A.; Schwartlander, Ruth; Moeller, Jens; Vogel, Viola

    2015-12-01

    Nuclear lamins play central roles at the intersection between cytoplasmic signalling and nuclear events. Here, we show that at least two N- and C-terminal lamin epitopes are not accessible at the basal side of the nuclear envelope under environmental conditions known to upregulate cell contractility. The conformational epitope on the Ig-domain of A-type lamins is more buried in the basal than apical nuclear envelope of human mesenchymal stem cells undergoing osteogenesis (but not adipogenesis), and in fibroblasts adhering to rigid (but not soft) polyacrylamide hydrogels. This structural polarization of the lamina is promoted by compressive forces, emerges during cell spreading, and requires lamin A/C multimerization, intact nucleoskeleton-cytoskeleton linkages (LINC), and apical-actin stress-fibre assembly. Notably, the identified Ig-epitope overlaps with emerin, DNA and histone binding sites, and comprises various laminopathy mutation sites. Our findings should help decipher how the physical properties of cellular microenvironments regulate nuclear events.

  13. Differential basal-to-apical accessibility of lamin A/C epitopes in the nuclear lamina regulated by changes in cytoskeletal tension

    PubMed Central

    Herzog, Florian A.; Schwartlander, Ruth; Moeller, Jens; Vogel, Viola

    2015-01-01

    Nuclear lamins play central roles at the intersection between cytoplasmic signalling and nuclear events. Here, we show that at least two N- and C-terminal lamin epitopes are not accessible at the basal side of the nuclear envelope under environmental conditions known to upregulate cell contractility. The conformational epitope on the Ig-domain of A-type lamins is more buried in the basal than apical nuclear envelope of human mesenchymal stem cells undergoing osteogenesis (but not adipogenesis), and in fibroblasts adhering to rigid (but not soft) polyacrylamide hydrogels. This structural polarization of the lamina is promoted by compressive forces, emerges during cell spreading, and requires lamin A/C multimerization, intact nucleoskeleton-cytoskeleton linkages (LINC), and apical-actin stress-fibre assembly. Notably, the identified Igepitope overlaps with emerin, DNA and histone binding sites, and comprises various laminopathy mutation sites. Our findings should help deciphering how the physical properties of cellular microenvironments regulate nuclear events. PMID:26301768

  14. Self-regulating control of parasitic loads in a fuel cell power system

    NASA Technical Reports Server (NTRS)

    Vasquez, Arturo (Inventor)

    2011-01-01

    A fuel cell power system comprises an internal or self-regulating control of a system or device requiring a parasitic load. The internal or self-regulating control utilizes certain components and an interconnection scheme to produce a desirable, variable voltage potential (i.e., power) to a system or device requiring parasitic load in response to varying operating conditions or requirements of an external load that is connected to a primary fuel cell stack of the system. Other embodiments comprise a method of designing such a self-regulated control scheme and a method of operating such a fuel cell power system.

  15. IL-1ra Secreted by ATP-Induced P2Y2 Negatively Regulates MUC5AC Overproduction via PLCβ3 during Airway Inflammation.

    PubMed

    Jeong, Jee-Yeong; Kim, Jiwook; Kim, Bokyoum; Kim, Joowon; Shin, Yusom; Kim, Judeok; Ryu, Siejeong; Yang, Yu-Mi; Song, Kyoung Seob

    2016-01-01

    Mucus secretion is often uncontrolled in many airway inflammatory diseases of humans. Identifying the regulatory pathway(s) of mucus gene expression, mucus overproduction, and hypersecretion is important to alleviate airway inflammation in these diseases. However, the regulatory signaling pathway controlling mucus overproduction has not been fully identified yet. In this study, we report that the ATP/P2Y2 complex secretes many cytokines and chemokines to regulate airway inflammation, among which IL-1 receptor antagonist (IL-1ra) downregulates MUC5AC gene expression via the inhibition of Gαq-induced Ca(2+) signaling. IL-1ra inhibited IL-1α protein expression and secretion, and vice versa. Interestingly, ATP/P2Y2-induced IL-1ra and IL-1α secretion were both mediated by PLCβ3. A dominant-negative mutation in the PDZ-binding domain of PLCβ3 inhibited ATP/P2Y2-induced IL-1ra and IL-1α secretion. IL-1α in the presence of the ATP/P2Y2 complex activated the ERK1/2 pathway in a greater degree and for a longer duration than the ATP/P2Y2 complex itself, which was dramatically inhibited by IL-1ra. These findings suggest that secreted IL-1ra exhibits a regulatory effect on ATP/P2Y2-induced MUC5AC gene expression, through inhibition of IL-1α secretion, to maintain the mucus homeostasis in the airway. Therefore, IL-1ra could be an excellent modality for regulating inflamed airway microenvironments in respiratory diseases.

  16. State regulation and power plant productivity: background and recommendations

    SciTech Connect

    Not Available

    1980-09-01

    This report was prepared by representatives of several state regulatory agencies. It is a guide to some of the activities currently under way in state agencies to promote increased availability of electrical generating power plants. Standard measures of plant performance are defined and the nature of data bases that report such measures is discussed. It includes reviews of current state, federal, and industry programs to enhance power plant productivity and provides detailed outlines of programs in effect in California, Illinois, Michigan, New York, North Carolina, Ohio, and Texas. A number of actions are presented that could be adopted by state regulatory agencies, depending on local conditions. They include: develop a commission position or policy statement to encourage productivity improvements by utilities; coordinate state efforts with ongoing industry and government programs to improve the acquisition of power plant performance data and the maintenance of quality information systems; acquire the capability to perform independent analyses of power plant productivity; direct the establishment of productivity improvement programs, including explicit performance objectives for both existing and planned power plants, and a performance program; establish a program of incentives to motivate productivity improvement activities; and participate in ongoing efforts at all levels and initiate new actions to promote productivity improvements.

  17. Note: A new regulation method of stable operation of high power cathode ion source

    SciTech Connect

    Jiang, C. C.; Xie, Y. H. Hu, C. D.; Xie, Y. L.; Liu, S.; Liang, L. Z.; Liu, Z. M.

    2015-05-15

    The hot cathode ion source will tend to be unstable when operated with high power and long pulse. In order to achieve stable operation, a new regulation method based on the arc power (discharge power) feedback control was designed and tested on the hot cathode ion source test bed with arc discharge and beam extraction. The results show that the new regulation method can achieve stable arc discharge and beam extraction. It verifies the success of feedback control of arc source with arc power.

  18. Fast switching, modular high-voltage DC/AC-power supplies for RF-Amplifiers and other applications

    SciTech Connect

    Alex, J.; Schminke, W.

    1995-12-31

    A new kind of high voltage high-power Pulse-Step Modulator (PSM) for broadcast transmitters, accelerator sources, for NBI (Neutral Beam Injection for Plasma Heating), gyrotrons and klystrons has been developed. Since its first introduction in 1984 for broadcast transmitters, more than 100 high-power sound broadcast transmitters had been equipped with the first generation of the PSM modulators, using Gate Turn-Off Thyristors (GTOs) as switching elements. Recently, due to faster switching elements and making use of the latest DSP technologies (Digital Signal Processing), the performance data and areas of application could be extended further. In 1994, a precision high voltage source for MW gyrotrons was installed at CRPP in Lausanne. Supplementary very low cost solutions for lower powers but high voltages had been developed. Hence, today, a large area of applications can be satisfied with the family of solutions. The paper describes the principle of operation, the related control systems and refers to some particular applications of the PSM amplifiers, especially the newest developments and corresponding field results.

  19. Quality Certification, Regulation and Power in Fair Trade

    ERIC Educational Resources Information Center

    Renard, Marie-Christine

    2005-01-01

    This article examines governance changes and shifting power relations within the fair-labelling network. These shifts are framed analytically by reference to broader changes in the agrofoods sector tied to the increasingly key role played by quality relations and standards in the production and marketing of food. The author argues that evident…

  20. Low Power Television: The Impact of the Final Regulations.

    ERIC Educational Resources Information Center

    Hsiung, James C.; And Others

    In August 1978, the Federal Communications Commission (FCC) began studying the question of how to increase the diversity and coverage of television broadcast services either by modifying the television translator rules or by creating a new low power television service (LPTV). In Septemer 1980, the FCC finally adopted a "Notice of Proposed…

  1. 48 CFR Appendixes A-C to Chapter 7 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false A Appendixes A-C to Chapter 7 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT Appendixes A-C to Chapter 7...

  2. 48 CFR Appendixes A-C to Chapter 7 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false A Appendixes A-C to Chapter 7 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT Appendixes A-C to Chapter 7...

  3. AcMNPV AC16 (DA26, BV/ODV-E26) regulates the levels of IE0 and IE1 and binds to both proteins via a domain located within the acidic transcriptional activation domain.

    PubMed

    Nie, Yingchao; Fang, Minggang; Theilmann, David A

    2009-03-15

    IE0 and IE1 are the primary viral regulatory proteins of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) involved in the transactivation of early genes, stimulation of late gene expression, and viral DNA replication. The protein interactions required for IE0 or IE1 to achieve these varied roles are not well defined, so to identify proteins that interact with IE0 and IE1, tandem affinity purification (TAP) and LC-MS/MS was used. Analysis of purified proteins identified AC16 (DA26, BV/ODV-E26) from TAP tagged IE0 virus infected Sf9 cells. Co-immunoprecipitation confirmed that AC16 interacts with both IE0 and IE1 and yeast 2-hybrid analysis mapped the domain required for interaction with AC16. Mutation of the AC16 binding domain enhanced BV production by viruses expressing only IE0 but had no effect if only IE1 is expressed. An ac16 deletion virus was constructed and was shown not to affect the temporal expression of IE0 and IE1; however the relative level of IE0 to IE1 was significantly increased.

  4. Dynamic Power Flow Controller: Compact Dynamic Phase Angle Regulators for Transmission Power Routing

    SciTech Connect

    2012-01-03

    GENI Project: Varentec is developing compact, low-cost transmission power controllers with fractional power rating for controlling power flow on transmission networks. The technology will enhance grid operations through improved use of current assets and by dramatically reducing the number of transmission lines that have to be built to meet increasing contributions of renewable energy sources like wind and solar. The proposed transmission controllers would allow for the dynamic control of voltage and power flow, improving the grid’s ability to dispatch power in real time to the places where it is most needed. The controllers would work as fail-safe devices whereby the grid would be restored to its present operating state in the event of a controller malfunction instead of failing outright. The ability to affordably and dynamically control power flow with adequate fail-safe switchgear could open up new competitive energy markets which are not possible under the current regulatory structure and technology base.

  5. Real power regulation design for multi-terminal VSC-HVDC systems

    NASA Astrophysics Data System (ADS)

    Li, Guo-Jie; Ruan, Si-Ye; Lie, Tek

    2013-06-01

    A multi-terminal voltage-source-converter (VSC) based high voltage direct current (HVDC) system is concerned for its flexibility and reliability. In this study, a control strategy for multiple VSCs is proposed to auto-share the real power variation without changing control mode, which is based on "dc voltage droop" power regulation functions. With the proposed power regulation design, the multiple VSCs automatically share the real power change and the VSC-HVDC system is stable even under loss of any one converter while there is no overloading for any individual converter. Simulation results show that it is effective to balance real power for power disturbance and thus improves operation reliability for the multi-terminal VSC-HVDC system by the proposed control strategy.

  6. 75 FR 3985 - Trade Regulation Rule Relating to Power Output Claims for Amplifiers Utilized in Home...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-26

    ... CFR Part 432 Trade Regulation Rule Relating to Power Output Claims for Amplifiers Utilized in Home... Rule Relating to Power Output Claims for Amplifiers Utilized in Home Entertainment Products (``Amplifier Rule'' or ``Rule''), as part of the Commission's systematic review of all current...

  7. Early Childhood Teachers and Regulation: Complicating Power Relations Using a Foucauldian Lens

    ERIC Educational Resources Information Center

    Fenech, Marianne; Sumsion, Jennifer

    2007-01-01

    This article both supports and complicates the positioning of reconceptualists who frame the regulation of early childhood services as repressive. Drawing on Foucault's construction of power and, in particular, his notion of an "analytics of power", the authors analyse findings from an Australian study investigating university-qualified…

  8. 75 FR 26225 - Frequency Regulation Compensation in the Organized Wholesale Power Markets; Notice of Technical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-11

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Frequency Regulation Compensation in the Organized Wholesale Power Markets... conference to elicit input on issues pertaining to Frequency Regulation Compensation in the ISO/RTO...

  9. Using Self-regulation to Successfully Overcome the Negotiation Disadvantage of Low Power

    PubMed Central

    Jäger, Andreas; Loschelder, David D.; Friese, Malte

    2017-01-01

    A plethora of studies has demonstrated that low-power negotiators attain lower outcomes compared to high-power negotiators. We argue that this low-power disadvantage can be conceptualized as impaired goal attainment and that self-regulation can help to overcome it. Three experiments tested this assertion. In Study 1, low-power negotiators attained lower profits compared to their high-power opponents in a face-to-face negotiation. Negotiators who set themselves goals and those who additionally formed if-then plans prior to the negotiation overcame the low-power disadvantage. Studies 2 and 3 replicated these effects in computer-mediated negotiations: Low-power negotiators conceded more than high-power negotiators. Again, setting goals and forming additional if-then plans helped to counter the power disadvantage. Process analyses revealed that negotiators’ concession-making at the start of the negotiation mediated both the low-power disadvantage and the beneficial effects of self-regulation. The present findings show how the low-power disadvantage unfolds in negotiations and how self-regulatory techniques can help to overcome it. PMID:28382005

  10. Flow Regulator Powered by the Stalk of Vorticella convarallia

    NASA Astrophysics Data System (ADS)

    Matsumoto, N.; Nagai, M.; Hayasaka, Y.; Oguri, M.; Kawashima, T.; Shibata, T.

    2012-03-01

    We propose flow regulation by the stalk of Vorticella convarallia. The motion of stalk can be controlled by introducing Ca2+ and chelator solutions alternatively. The fluid channel is narrowed by fully extended V. convarallia, which results in increasing fluidic resistance and reducing flow rate. The flow regulator consists of a microchannel and Vorticella. The microchannel has two layers. The top layer contains a fluid channel where Vorticella is stored to control the flow rate. The bottom layer includes a control channel which enables control of the fluid channel by an external compressed air supply. After cells were introduced to the device at 1.0×103 cells/μL, eight of 18 chambers contained more than a single cell. Four cells of Vorticella were cultured in one chamber at a maximum. The cells were alive for two days after the injection. We evaluated the change in mean flow rate through the fluidic channel. The flow rate without V. convarallia increased linearly from 5.5nL/min to 1.1μL/min with applied pressure from 4 to 18kPa. The switching time of solutions measured two seconds at 10 kPa. The response time for the device was estimated to be approximately four seconds after the partial removal of cell membrane.

  11. Real power regulation for the utility power grid via responsive loads

    DOEpatents

    McIntyre, Timothy J [Knoxville, TN; Kirby, Brendan J [Knoxville, TN; Kisner, Roger A

    2009-05-19

    A system for dynamically managing an electrical power system that determines measures of performance and control criteria for the electric power system, collects at least one automatic generation control (AGC) input parameter to at least one AGC module and at least one automatic load control (ALC) input parameter to at least one ALC module, calculates AGC control signals and loads as resources (LAR) control signals in response to said measures of performance and control criteria, propagates AGC control signals to power generating units in response to control logic in AGC modules, and propagates LAR control signals to at least one LAR in response to control logic in ALC modules.

  12. Modeling and Performance Improvement of the Constant Power Regulator Systems in Variable Displacement Axial Piston Pump

    PubMed Central

    Park, Sung Hwan; Lee, Ji Min; Kim, Jong Shik

    2013-01-01

    An irregular performance of a mechanical-type constant power regulator is considered. In order to find the cause of an irregular discharge flow at the cut-off pressure area, modeling and numerical simulations are performed to observe dynamic behavior of internal parts of the constant power regulator system for a swashplate-type axial piston pump. The commercial numerical simulation software AMESim is applied to model the mechanical-type regulator with hydraulic pump and simulate the performance of it. The validity of the simulation model of the constant power regulator system is verified by comparing simulation results with experiments. In order to find the cause of the irregular performance of the mechanical-type constant power regulator system, the behavior of main components such as the spool, sleeve, and counterbalance piston is investigated using computer simulation. The shape modification of the counterbalance piston is proposed to improve the undesirable performance of the mechanical-type constant power regulator. The performance improvement is verified by computer simulation using AMESim software. PMID:24282389

  13. Modeling and performance improvement of the constant power regulator systems in variable displacement axial piston pump.

    PubMed

    Park, Sung Hwan; Lee, Ji Min; Kim, Jong Shik

    2013-01-01

    An irregular performance of a mechanical-type constant power regulator is considered. In order to find the cause of an irregular discharge flow at the cut-off pressure area, modeling and numerical simulations are performed to observe dynamic behavior of internal parts of the constant power regulator system for a swashplate-type axial piston pump. The commercial numerical simulation software AMESim is applied to model the mechanical-type regulator with hydraulic pump and simulate the performance of it. The validity of the simulation model of the constant power regulator system is verified by comparing simulation results with experiments. In order to find the cause of the irregular performance of the mechanical-type constant power regulator system, the behavior of main components such as the spool, sleeve, and counterbalance piston is investigated using computer simulation. The shape modification of the counterbalance piston is proposed to improve the undesirable performance of the mechanical-type constant power regulator. The performance improvement is verified by computer simulation using AMESim software.

  14. A transdiagnostic approach to examining the incremental predictive power of emotion regulation and basic personality dimensions.

    PubMed

    Stanton, Kasey; Rozek, David C; Stasik-O'Brien, Sara M; Ellickson-Larew, Stephanie; Watson, David

    2016-10-01

    Although personality and emotion regulation abilities appear to overlap considerably, few studies have adopted an integrative approach by examining personality and emotion regulation together. Therefore, it is unclear how much incremental power emotion regulation demonstrates in predicting psychopathology beyond personality traits, and vice versa. Results from a community sample characterized by high levels of psychopathology (N = 299) indicated that personality and emotion regulation represent strongly related but distinguishable constructs, with both showing incremental power beyond the other in many cases in predicting self-reported and interview-rated psychopathology. More specifically, difficulties in responding adaptively to negative emotional experiences displayed predictive power beyond neuroticism and other personality traits in predicting internalizing psychopathology and psychoticism. Conversely, neuroticism displayed substantial incremental predictive power beyond emotion regulation and other five-factor model traits, especially for anxiety and other internalizing psychopathology. Other five-factor model traits also showed incremental predictive power in specific cases (e.g., agreeableness and conscientiousness showed specificity in predicting antagonism and disinhibition, respectively). These data provide a starting point for developing a finer-grained understanding of how emotion dysregulation and personality traits are implicated in a range of psychopathology, highlighting the value of adopting an integrative approach of examining emotion regulation and personality traits concurrently. (PsycINFO Database Record

  15. Input-current shaped ac to dc converters

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The problem of achieving near unity power factor while supplying power to a dc load from a single phase ac source of power is examined. Power processors for this application must perform three functions: input current shaping, energy storage, and output voltage regulation. The methods available for performing each of these three functions are reviewed. Input current shaping methods are either active or passive, with the active methods divided into buck-like and boost-like techniques. In addition to large reactances, energy storage methods include resonant filters, active filters, and active storage schemes. Fast voltage regulation can be achieved by post regulation or by supplementing the current shaping topology with an extra switch. Some indications of which methods are best suited for particular applications concludes the discussion.

  16. Design and implementation of co-operative control strategy for hybrid AC/DC microgrids

    NASA Astrophysics Data System (ADS)

    Mahmud, Rasel

    This thesis is mainly divided in two major sections: 1) Modeling and control of AC microgrid, DC microgrid, Hybrid AC/DC microgrid using distributed co-operative control, and 2) Development of a four bus laboratory prototype of an AC microgrid system. At first, a distributed cooperative control (DCC) for a DC microgrid considering the state-of-charge (SoC) of the batteries in a typical plug-in-electric-vehicle (PEV) is developed. In DC microgrids, this methodology is developed to assist the load sharing amongst the distributed generation units (DGs), according to their ratings with improved voltage regulation. Subsequently, a DCC based control algorithm for AC microgrid is also investigated to improve the performance of AC microgrid in terms of power sharing among the DGs, voltage regulation and frequency deviation. The results validate the advantages of the proposed methodology as compared to traditional droop control of AC microgrid. The DCC-based control methodology for AC microgrid and DC microgrid are further expanded to develop a DCC-based power management algorithm for hybrid AC/DC microgrid. The developed algorithm for hybrid microgrid controls the power flow through the interfacing converter (IC) between the AC and DC microgrids. This will facilitate the power sharing between the DGs according to their power ratings. Moreover, it enables the fixed scheduled power delivery at different operating conditions, while maintaining good voltage regulation and improved frequency profile. The second section provides a detailed explanation and step-by-step design and development of an AC/DC microgrid testbed. Controllers for the three-phase inverters are designed and tested on different generation units along with their corresponding inductor-capacitor-inductor (LCL) filters to eliminate the switching frequency harmonics. Electric power distribution line models are developed to form the microgrid network topology. Voltage and current sensors are placed in the proper

  17. Combined Operation of AC and DC Distribution System with Distributed Generation Units

    NASA Astrophysics Data System (ADS)

    Noroozian, Reza; Abedi, Mehrdad; Gharehpetian, Gevorg

    2010-07-01

    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.

  18. Problems of standardizing and technical regulation in the electric power industry

    NASA Astrophysics Data System (ADS)

    Grabchak, E. P.

    2016-12-01

    A mandatory condition to ensure normal operation of a power system and efficiency in the sector is standardization and legal regulation of technological activities of electric power engineering entities and consumers. Compared to the times of USSR, the present-time technical guidance documents are not mandatory to follow in most cases, being of an advisory nature due to the lack of new ones. During the last five years, the industry has been showing a deterioration of the situation in terms of ensuring reliability and engineering controllability as a result of the dominant impact of short-term market stimuli and the differences in basic technological policies. In absence of clear requirements regarding the engineering aspects of such activities, production operation does not contribute to the preserving of technical integrity of the Russian power system, which leads to the loss of performance capability and controllability and causes disturbances in the power supply to consumers. The result of this problem is a high rate of accident incidence. The dynamics of accidents by the type of equipment is given, indicating a persisting trend of growth in the number of accidents, which are of a systematic nature. Several problematic aspects of engineering activities of electric power engineering entities, requiring standardization and legal regulation are pointed out: in the domestic power system, a large number of power electrotechnical and generating equipment operate along with systems of regulation, which do not comply with the principles and technical rules representing a framework where the Energy System of Russia is built and functioning

  19. Genome-Wide Gene/Genome Dosage Imbalance Regulates Gene Expressions in Synthetic Brassica napus and Derivatives (AC, AAC, CCA, CCAA)

    PubMed Central

    Tan, Chen; Pan, Qi; Cui, Cheng; Xiang, Yi; Ge, Xianhong; Li, Zaiyun

    2016-01-01

    Gene/genome dosage balance is an essential evolutionary mechanism for organisms to ensure a normal function, but the underlying causes of dosage-imbalance regulation remain poorly understood. Herein, the serial Brassica hybrids/polyploids (AC, AAC, CCA, CCAA) with different copies of A and C subgenomes from the same two parents of Brassica rapa and Brassica oleracea were synthesized to investigate the effects of genome dosages on gene expressions and interactions by using RNA-Seq. The expression changes of A- and C-subgenome genes were consistent with dosage alterations. Dosage-dependent and -independent genes were grouped according to the correlations between dosage variations and gene expressions. Expression levels of dosage-dependent genes were strongly correlated with dosage changes and mainly contributed to dosage effects, while those of dosage-independent genes gave weak correlations with dosage variations and mostly facilitated dosage compensation. More protein–protein interactions were detected for dosage-independent genes than dosage-dependent ones, as predicted by the dosage balance hypothesis. Dosage-dependent genes more likely impacted the expressions by trans effects, whereas dosage-independent genes preferred to play by cis effects. Furthermore, dosage-dependent genes were mainly associated with the basic biological processes to maintain the stability of the growth and development, while dosage-independent genes were more enriched in the stress response related processes to accelerate adaptation. The present comprehensive analysis of gene expression dependent/independent on dosage alterations in Brassica polyploids provided new insights into gene/genome dosage-imbalance regulation of gene expressions. PMID:27721820

  20. Genome-Wide Gene/Genome Dosage Imbalance Regulates Gene Expressions in Synthetic Brassica napus and Derivatives (AC, AAC, CCA, CCAA).

    PubMed

    Tan, Chen; Pan, Qi; Cui, Cheng; Xiang, Yi; Ge, Xianhong; Li, Zaiyun

    2016-01-01

    Gene/genome dosage balance is an essential evolutionary mechanism for organisms to ensure a normal function, but the underlying causes of dosage-imbalance regulation remain poorly understood. Herein, the serial Brassica hybrids/polyploids (AC, AAC, CCA, CCAA) with different copies of A and C subgenomes from the same two parents of Brassica rapa and Brassica oleracea were synthesized to investigate the effects of genome dosages on gene expressions and interactions by using RNA-Seq. The expression changes of A- and C-subgenome genes were consistent with dosage alterations. Dosage-dependent and -independent genes were grouped according to the correlations between dosage variations and gene expressions. Expression levels of dosage-dependent genes were strongly correlated with dosage changes and mainly contributed to dosage effects, while those of dosage-independent genes gave weak correlations with dosage variations and mostly facilitated dosage compensation. More protein-protein interactions were detected for dosage-independent genes than dosage-dependent ones, as predicted by the dosage balance hypothesis. Dosage-dependent genes more likely impacted the expressions by trans effects, whereas dosage-independent genes preferred to play by cis effects. Furthermore, dosage-dependent genes were mainly associated with the basic biological processes to maintain the stability of the growth and development, while dosage-independent genes were more enriched in the stress response related processes to accelerate adaptation. The present comprehensive analysis of gene expression dependent/independent on dosage alterations in Brassica polyploids provided new insights into gene/genome dosage-imbalance regulation of gene expressions.

  1. 20 kHz main inverter unit. [for space station power supplies

    NASA Technical Reports Server (NTRS)

    Hussey, S.

    1989-01-01

    A proof-of-concept main inverter unit has demonstrated the operation of a pulse-width-modulated parallel resonant power stage topology as a 20-kHz ac power source driver, showing simple output regulation, parallel operation, power sharing and short-circuit operation. The use of a two-stage dc input filter controls the electromagnetic compatibility (EMC) characteristics of the dc power bus, and the use of an ac harmonic trap controls the EMC characteristics of the 20-kHz ac power bus.

  2. Electric power: contemporary issues and the federal role in oversight and regulation

    SciTech Connect

    Not Available

    1981-12-21

    Electric power will play an important role in the Nation's energy picture, but rapidly increasing fuel prices, lower growth rates, and difficulties in developing large powerplants have made it difficult for electric utilities to provide adequate supplies of power at prices the public is willing to pay. This report provides the Congress with a discussion of: important issues in electric power regulation and management, recent GAO reports on some of those issues, and questions and observations about power system planning and development which deserve Federal attention. It specifically highlights important electric power issues which transcend State, regional, and utility decisionmaking and identifies for the Congress significant areas which should be considered when making decisions affecting the electric power industry.

  3. Modelling and Simulation of Single-Phase Series Active Compensator for Power Quality Improvement

    NASA Astrophysics Data System (ADS)

    Verma, Arun Kumar; Mathuria, Kirti; Singh, Bhim; Bhuvaneshwari, G.

    2016-10-01

    A single-phase active series compensator is proposed in this work to reduce harmonic currents at the ac mains and to regulate the dc link voltage of a diode bridge rectifier (DBR) that acts as the front end converter for a voltage source inverter feeding an ac motor. This ac motor drive is used in any of the domestic, commercial or industrial appliances. Under fluctuating ac mains voltages, the dc link voltage of the DBR depicts wide variations and hence the ac motor is used at reduced rating as compared to its name-plate rating. The active series compensator proposed here provides dual functions of improving the power quality at the ac mains and regulating the dc link voltage thus averting the need for derating of the ac motor.

  4. Small size transformer provides high power regulation with low ripple and maximum control

    NASA Technical Reports Server (NTRS)

    Manoli, R.; Ulrich, B. R.

    1971-01-01

    Single, variable, transformer/choke device does work of several. Technique reduces drawer assembly physical size and design and manufacturing cost. Device provides power, voltage current and impedance regulation while maintaining maximum control of linearity and ensuring extremely low ripple. Nulling is controlled to very fine degree.

  5. A new system architecture improves output power regulation in electrosurgical generators.

    PubMed

    Friedrichs, Daniel A; Erickson, Robert W; Gilbert, James

    2011-01-01

    A new system architecture for electrosurgical generators inherently produces the ideal electrosurgical output characteristic with near-deadbeat control. Compared to existing technology, this converter significantly improves power regulation, leading to improved surgical outcomes by minimizing thermal spread and tissue charring.

  6. Modeling and Verification of Distributed Generation and Voltage Regulation Equipment for Unbalanced Distribution Power Systems; Annual Subcontract Report, June 2007

    SciTech Connect

    Davis, M. W.; Broadwater, R.; Hambrick, J.

    2007-07-01

    This report summarizes the development of models for distributed generation and distribution circuit voltage regulation equipment for unbalanced power systems and their verification through actual field measurements.

  7. Distributed cooperative regulation for multiagent systems and its applications to power systems: a survey.

    PubMed

    Hu, Jianqiang; Li, Yaping; Yong, Taiyou; Cao, Jinde; Yu, Jie; Mao, Wenbo

    2014-01-01

    Cooperative regulation of multiagent systems has become an active research area in the past decade. This paper reviews some recent progress in distributed coordination control for leader-following multiagent systems and its applications in power system and mainly focuses on the cooperative tracking control in terms of consensus tracking control and containment tracking control. Next, methods on how to rank the network nodes are summarized for undirected/directed network, based on which one can determine which follower should be connected to leaders such that partial followers can perceive leaders' information. Furthermore, we present a survey of the most relevant scientific studies investigating the regulation and optimization problems in power systems based on distributed strategies. Finally, some potential applications in the frequency tracking regulation of smart grids are discussed at the end of the paper.

  8. Distributed Cooperative Regulation for Multiagent Systems and Its Applications to Power Systems: A Survey

    PubMed Central

    Li, Yaping; Yong, Taiyou; Yu, Jie; Mao, Wenbo

    2014-01-01

    Cooperative regulation of multiagent systems has become an active research area in the past decade. This paper reviews some recent progress in distributed coordination control for leader-following multiagent systems and its applications in power system and mainly focuses on the cooperative tracking control in terms of consensus tracking control and containment tracking control. Next, methods on how to rank the network nodes are summarized for undirected/directed network, based on which one can determine which follower should be connected to leaders such that partial followers can perceive leaders' information. Furthermore, we present a survey of the most relevant scientific studies investigating the regulation and optimization problems in power systems based on distributed strategies. Finally, some potential applications in the frequency tracking regulation of smart grids are discussed at the end of the paper. PMID:25243199

  9. Active power control of solar PV generation for large interconnection frequency regulation and oscillation damping

    DOE PAGES

    Liu, Yong; Zhu, Lin; Zhan, Lingwei; ...

    2015-06-23

    Because of zero greenhouse gas emission and decreased manufacture cost, solar photovoltaic (PV) generation is expected to account for a significant portion of future power grid generation portfolio. Because it is indirectly connected to the power grid via power electronic devices, solar PV generation system is fully decoupled from the power grid, which will influence the interconnected power grid dynamic characteristics as a result. In this study, the impact of solar PV penetration on large interconnected power system frequency response and inter-area oscillation is evaluated, taking the United States Eastern Interconnection (EI) as an example. Furthermore, based on the constructedmore » solar PV electrical control model with additional active power control loops, the potential contributions of solar PV generation to power system frequency regulation and oscillation damping are examined. The advantages of solar PV frequency support over that of wind generator are also discussed. Finally, simulation results demonstrate that solar PV generations can effectively work as ‘actuators’ in alleviating the negative impacts they bring about.« less

  10. Active power control of solar PV generation for large interconnection frequency regulation and oscillation damping

    SciTech Connect

    Liu, Yong; Zhu, Lin; Zhan, Lingwei; Gracia, Jose R.; King, Thomas Jr.; Liu, Yilu

    2015-06-23

    Because of zero greenhouse gas emission and decreased manufacture cost, solar photovoltaic (PV) generation is expected to account for a significant portion of future power grid generation portfolio. Because it is indirectly connected to the power grid via power electronic devices, solar PV generation system is fully decoupled from the power grid, which will influence the interconnected power grid dynamic characteristics as a result. In this study, the impact of solar PV penetration on large interconnected power system frequency response and inter-area oscillation is evaluated, taking the United States Eastern Interconnection (EI) as an example. Furthermore, based on the constructed solar PV electrical control model with additional active power control loops, the potential contributions of solar PV generation to power system frequency regulation and oscillation damping are examined. The advantages of solar PV frequency support over that of wind generator are also discussed. Finally, simulation results demonstrate that solar PV generations can effectively work as ‘actuators’ in alleviating the negative impacts they bring about.

  11. Lightweight Battery Charge Regulator Used to Track Solar Array Peak Power

    NASA Technical Reports Server (NTRS)

    Soeder, James F.; Button, Robert M.

    1999-01-01

    A battery charge regulator based on the series-connected boost regulator (SCBR) technology has been developed for high-voltage spacecraft applications. The SCBR regulates the solar array power during insolation to prevent battery overcharge or undercharge conditions. It can also be used to provide regulated battery output voltage to spacecraft loads if necessary. This technology uses industry-standard dc-dc converters and a unique interconnection to provide size, weight, efficiency, fault tolerance, and modularity benefits over existing systems. The high-voltage SCBR shown in the photograph has demonstrated power densities of over 1000 watts per kilogram (W/kg). Using four 150-W dc-dc converter modules, it can process 2500 W of power at 120 Vdc with a minimum input voltage of 90 Vdc. Efficiency of the SCBR was 94 to 98 percent over the entire operational range. Internally, the unit is made of two separate SCBR s, each with its own analog control circuitry, to demonstrate the modularity of the technology. The analog controllers regulate the output current and incorporate the output voltage limit with active current sharing between the two units. They also include voltage and current telemetry, on/off control, and baseplate temperature sensors. For peak power tracking, the SCBR was connected to a LabView-based data acquisition system for telemetry and control. A digital control algorithm for tracking the peak power point of a solar array was developed using the principle of matching the source impedance with the load impedance for maximum energy transfer. The algorithm was successfully demonstrated in a simulated spacecraft electrical system at the Boeing PhantomWorks High Voltage Test Facility in Seattle, Washington. The system consists of a 42-string, high-voltage solar array simulator, a 77-cell, 80-ampere-hour (A-hr) nickel-hydrogen battery, and a constant power-load module. The SCBR and the LabView control algorithm successfully tracked the solar array peak

  12. 47 CFR 74.789 - Broadcast regulations applicable to digital low power television and television translator stations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Broadcast regulations applicable to digital low....789 Broadcast regulations applicable to digital low power television and television translator stations. The following sections are applicable to digital low power television and television...

  13. 47 CFR 74.789 - Broadcast regulations applicable to digital low power television and television translator stations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Broadcast regulations applicable to digital low....789 Broadcast regulations applicable to digital low power television and television translator stations. The following sections are applicable to digital low power television and television...

  14. 47 CFR 74.789 - Broadcast regulations applicable to digital low power television and television translator stations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Broadcast regulations applicable to digital low....789 Broadcast regulations applicable to digital low power television and television translator stations. The following sections are applicable to digital low power television and television...

  15. 47 CFR 74.789 - Broadcast regulations applicable to digital low power television and television translator stations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Broadcast regulations applicable to digital low....789 Broadcast regulations applicable to digital low power television and television translator stations. The following sections are applicable to digital low power television and television...

  16. 47 CFR 74.789 - Broadcast regulations applicable to digital low power television and television translator stations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Broadcast regulations applicable to digital low....789 Broadcast regulations applicable to digital low power television and television translator stations. The following sections are applicable to digital low power television and television...

  17. Soft-stall control versus furling control for small wind turbine power regulation

    SciTech Connect

    Muljadi, E; Forsyth, T; Butterfield, C P

    1998-07-01

    Many small wind turbines are designed to furl (turn) in high winds to regulate power and provide overspeed protection. Furling control results in poor energy capture at high wind speeds. This paper proposes an alternative control strategy for small wind turbines -- the soft-stall control method. The furling and soft-stall control strategies are compared using steady state analysis and dynamic simulation analysis. The soft-stall method is found to offer several advantages: increased energy production at high wind speeds, energy production which tracks the maximum power coefficient at low to medium wind speeds, reducing furling noise, and reduced thrust.

  18. Soft-Stall Control versus Furling Control for Small Wind Turbine Power Regulation

    SciTech Connect

    Muljadi, E.; Forsyth, T.; Butterfield, C. P.

    1998-07-01

    Many small wind turbines are designed to furl (turn) in high winds to regulate power and provide overspeed protection. Furling control results in poor energy capture at high wind speeds. This paper proposes an alternative control strategy for small wind turbines -- the soft-stall method. The furling and soft-stall control strategies are compared using steady state analysis and dynamic simulation analysis. The soft-stall method is found to offer several advantages: increased energy production at high wind speeds, energy production which tracks the maximum power coefficient at low to medium wind speeds, reduced furling noise, and reduced thrust.

  19. High voltage solar cell power generating system for regulated solar array development

    NASA Technical Reports Server (NTRS)

    Levy, E., Jr.; Hoffman, A. C.

    1973-01-01

    A laboratory solar power system regulated by on-panel switches has been delivered for operating high power (3 kw), high voltage (15,000 volt) loads (communication tubes, ion thrusters). The modular system consists of 26 solar arrays, each with an integral light source and cooling system. A typical array contains 2560 series-connected cells. Each light source consists of twenty 500 watt tungsten iodide lamps providing plus or minus 5 per cent uniformity at one solar constant. An array temperature of less than 40 C is achieved using an infrared filter, a water cooled plate, a vacuum hold-down system, and air flushing.

  20. Efficiency and Regulation of Commercial Low Power DC/DC Converter Modules at Low Temperatures

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.

    2000-01-01

    DC/DC converters that are capable of operating at cryogenic temperatures are anticipated to play an important role in the power systems of future NASA deep space missions. Design of these converters to survive cryogenic temperatures will improve the power system performance, and reduce development and launch costs. At the NASA Glenn Research Center Low Temperature Electronics Laboratory, several commercial off-the-shelf dc/dc converter modules were evaluated for their low temperature performance. Various parameters were investigated as a function of temperature, in the range of 20 C to -190 C. Data pertaining to the efficiency and voltage regulation of the tested converters is presented and discussed.

  1. Economic and safety analysis of unconventional peak regulation on power unit of peak shifting start-stop

    NASA Astrophysics Data System (ADS)

    Cao, X.; Zhao, J. F.; Duan, X. Q.; Jin, Y. A.

    2017-01-01

    Tthe capacity difference of peak regulation between the power gird and the actual demand has become a serious problem considering the growth in the difference between electricity supply and demand. Therefore, peak regulation of power grid needs to be deeply studied. Unconventional peak regulation on unit of peak shifting start-stop is a way that can broaden the range of power regulation, as well as benefit safe operation of the power grid. However, it requires frequent and fast unit start-stop, complex operation, and more staff labor. By carrying out unconventional thermal power unit load test, the start-stop mode of peak auxiliary equipment is studied in this paper, indicating that it has a positive effect on safety and economic of load-peaking operation. The best working conditions of the peak units is found by analysing consumption cost, safety specifications, and life lost of the start-stop peak regulation mode.

  2. Power flow controller with a fractionally rated back-to-back converter

    DOEpatents

    Divan, Deepakraj M.; Kandula, Rajendra Prasad; Prasai, Anish

    2016-03-08

    A power flow controller with a fractionally rated back-to-back (BTB) converter is provided. The power flow controller provide dynamic control of both active and reactive power of a power system. The power flow controller inserts a voltage with controllable magnitude and phase between two AC sources at the same frequency; thereby effecting control of active and reactive power flows between the two AC sources. A transformer may be augmented with a fractionally rated bi-directional Back to Back (BTB) converter. The fractionally rated BTB converter comprises a transformer side converter (TSC), a direct-current (DC) link, and a line side converter (LSC). By controlling the switches of the BTB converter, the effective phase angle between the two AC source voltages may be regulated, and the amplitude of the voltage inserted by the power flow controller may be adjusted with respect to the AC source voltages.

  3. Applying and adapting the Swedish regulatory system for decommissioning to nuclear power reactors - The regulator's perspective.

    PubMed

    Amft, Martin; Leisvik, Mathias; Carroll, Simon

    2017-03-16

    Half of the original 13 Swedish nuclear power reactors will be shut down by 2020. The decommissioning of these reactors is a challenge for all parties involved, including the licensees, the waste management system, the financing system, and the Swedish Radiation Safety Authority (SSM). This paper presents an overview of the Swedish regulations for decommissioning of nuclear facilities. It describes some of the experiences that SSM has gained from the application of these regulations. The focus of the present paper is on administrative aspects of decommissioning, such as SSM's guidelines, the definition of fundamental concepts in the regulatory framework, and a proposed revision of the licensing process according to the Environmental Act. These improvements will help to streamline the administration of the commercial nuclear power plant decommissioning projects that are anticipated to commence in Sweden in the near future.

  4. Power spectra and cooperativity of a calcium-regulated cation channel.

    PubMed

    McGeoch, M W; McGeoch, J E

    1994-01-01

    In this article we show that a channel complex of cooperatively interacting subunits can produce a power law spectrum with the slope of the spectrum depending on the strength of the cooperative interaction. The effects of cooperativity are explored via a computational model of a calcium-regulated cation channel for which new data is presented. The results, which concern "flickering" conductances, are correlated with prior work on critical fluctuations in the Ising model of ferromagnetism.

  5. 25 CFR 518.12 - Which investigative or enforcement powers of the Commission are inapplicable to self-regulating...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Commission are inapplicable to self-regulating tribes? 518.12 Section 518.12 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR GENERAL PROVISIONS SELF-REGULATION OF CLASS II GAMING § 518.12 Which... time in which a tribe has a certificate of self-regulation, the powers of the Commission, as set...

  6. Trends in the use of digital technology for control and regulation of power supplies.

    SciTech Connect

    Carwardine, J.; Lenkszus, F.

    1999-10-22

    Since the availability of computers, accelerator power supplies have relied on digital technology in some way, from such simple tasks as turning the supplies on and off to the supplying of computer-controlled references. However, advances in digital technology, both in performance and cost, allow considerably more than simple control and monitoring. This, coupled with increasing demand for higher performance and monitoring capabilities, has made it appealing to integrate such technology into power supply designs. This paper will review current trends in the use of such advanced technology as embedded DSP controllers, and the application of real-time algorithms to the regulation and control of power supplies for accelerators and other large-scale physics applications.

  7. Technology diffusion and environmental regulation: Evidence from electric power plants under the Clean Air Act

    NASA Astrophysics Data System (ADS)

    Frey, Elaine F.

    Even though environmental policy can greatly affect the path of technology diffusion, the economics literature contains limited empirical evidence of this relationship. My research will contribute to the available evidence by providing insight into the technology adoption decisions of electric generating firms. Since policies are often evaluated based on the incentives they provide to promote adoption of new technologies, it is important that policy makers understand the relationship between technological diffusion and regulation structure to make informed decisions. Lessons learned from this study can be used to guide future policies such as those directed to mitigate climate change. I first explore the diffusion of scrubbers, a sulfur dioxide (SO 2) abatement technology, in response to federal market-based regulations and state command-and-control regulations. I develop a simple theoretical model to describe the adoption decisions of scrubbers and use a survival model to empirically test the theoretical model. I find that power plants with strict command-and-control regulations have a high probability of installing a scrubber. These findings suggest that although market-based regulations have encouraged diffusion, many scrubbers have been installed because of state regulatory pressure. Although tradable permit systems are thought to give firms more flexibility in choosing abatement technologies, I show that interactions between a permit system and pre-existing command-and-control regulations can limit that flexibility. In a separate analysis, I explore the diffusion of combined cycle (CC) generating units, which are natural gas-fired generating units that are cleaner and more efficient than alternative generating units. I model the decision to consider adoption of a CC generating unit and the extent to which the technology is adopted in response to environmental regulations imposed on new sources of pollutants. To accomplish this, I use a zero-inflated Poisson

  8. Coordination and decision making of regulation, operation, and market activities in power systems

    NASA Astrophysics Data System (ADS)

    Nakashima, Tomoaki

    Electric power has been traditionally supplied to customers at regulated rates by vertically integrated utilities (VIUs), which own generation, transmission, and distribution systems. However, the regulatory authorities of VIUs are promoting competition in their businesses to lower the price of electric energy. Consequently, in new deregulated circumstances, many suppliers and marketers compete in the generation market, and conflict of interest may often occur over transmission. Therefore, a neutral entity, called an independent system operator (ISO), which operates the power system independently, has been established to give market participants nondiscriminatory access to transmission sectors with a natural monopoly, and to facilitate competition in generation sectors. Several types of ISOs are established at present, with their respective regions and authorities. The ISO receives many requests from market participants to transfer power, and must evaluate the feasibility of their requests under the system's condition. In the near future, regulatory authorities may impose various objectives on the ISOs. Then, based on the regulators' policies, the ISO must determine the optimal schedules from feasible solutions, or change the market participants' requests. In a newly developed power market, market participants will conduct their transactions in order to maximize their profit. The most crucial information in conducting power transactions is price and demand. A direct transaction between suppliers and consumers may become attractive because of its stability of price, while in a power exchange market, gaming and speculation of participants may push up electricity prices considerably. To assist the consumers in making effective decisions, suitable methods for forecasting volatile market price are necessary. This research has been approached from three viewpoints: Firstly, from the system operator's point of view, desirable system operation and power market structure

  9. Observation of Unidirectional Current Rectification and AC-to-DC Power Conversion by As-Grown Single-Walled Carbon Nanotube Transistors

    DTIC Science & Technology

    2008-12-01

    irregularities and possibly due to change in the chirality of a single tube. Utilizing the fabricated SWNT FETs for the first time, a nanoscale AC-to...al., 2000, Lee et al., 2004). Theoretical predictions suggest the cross or Y-type junctions, atomic defect, and/or changes in chirality along...property due to the hybrid chirality of single tubes. The electronic structure of the nanotubes depend on their diameter and helicity (Saito et. al

  10. Automatic system for regulating the frequency and power of the 500 MW coal-dust power generating units at the Reftinskaya GRES

    SciTech Connect

    Bilenko, V. A.; Gal'perina, A. I.; Mikushevich, E. E.; Nikol'skii, D. Yu.; Zhugrin, A. G.; Bebenin, P. A.; Syrchin, M. V.

    2009-03-15

    The monitoring and control systems at the 500 MW coal-dust power generating units No. 7, 8, and 9 at the Reftinskaya GRES have been modernized using information-regulator systems. Layouts for instrumental construction of these systems and expanded algorithmic schemes for the automatic frequency and power control system and for the boiler supply and fuelling are discussed. Results from tests and normal operation of the automatic frequency and power control system are presented.

  11. Three-phase-to-two-phase direct AC-AC converter with three leg structure

    NASA Astrophysics Data System (ADS)

    Kwak, S.-S.

    2014-05-01

    A three-phase-to-two-phase ac-ac converter is, along with a modulation strategy based on the space vector scheme, introduced to directly drive two-phase output ac systems with high input power quality. The converter is capable of synthesising two sinusoidal output voltages with variable output frequency and arbitrary magnitude in quadrature phase-shift as well as sinusoidal input currents.

  12. Committing to coal and gas: Long-term contracts, regulation, and fuel switching in power generation

    NASA Astrophysics Data System (ADS)

    Rice, Michael

    Fuel switching in the electricity sector has important economic and environmental consequences. In the United States, the increased supply of gas during the last decade has led to substantial switching in the short term. Fuel switching is constrained, however, by the existing infrastructure. The power generation infrastructure, in turn, represents commitments to specific sources of energy over the long term. This dissertation explores fuel contracts as the link between short-term price response and long-term plant investments. Contracting choices enable power plant investments that are relationship-specific, often regulated, and face uncertainty. Many power plants are subject to both hold-up in investment and cost-of-service regulation. I find that capital bias is robust when considering either irreversibility or hold-up due to the uncertain arrival of an outside option. For sunk capital, the rental rate is inappropriate for determining capital bias. Instead, capital bias depends on the regulated rate of return, discount rate, and depreciation schedule. If policies such as emissions regulations increase fuel-switching flexibility, this can lead to capital bias. Cost-of-service regulation can shorten the duration of a long-term contract. From the firm's perspective, the existing literature provides limited guidance when bargaining and writing contracts for fuel procurement. I develop a stochastic programming framework to optimize long-term contracting decisions under both endogenous and exogenous sources of hold-up risk. These typically include policy changes, price shocks, availability of fuel, and volatility in derived demand. For price risks, the optimal contract duration is the moment when the expected benefits of the contract are just outweighed by the expected opportunity costs of remaining in the contract. I prove that imposing early renegotiation costs decreases contract duration. Finally, I provide an empirical approach to show how coal contracts can limit

  13. Digital ac monitor

    DOEpatents

    Hart, George W.; Kern, Jr., Edward C.

    1987-06-09

    An apparatus and method is provided for monitoring a plurality of analog ac circuits by sampling the voltage and current waveform in each circuit at predetermined intervals, converting the analog current and voltage samples to digital format, storing the digitized current and voltage samples and using the stored digitized current and voltage samples to calculate a variety of electrical parameters; some of which are derived from the stored samples. The non-derived quantities are repeatedly calculated and stored over many separate cycles then averaged. The derived quantities are then calculated at the end of an averaging period. This produces a more accurate reading, especially when averaging over a period in which the power varies over a wide dynamic range. Frequency is measured by timing three cycles of the voltage waveform using the upward zero crossover point as a starting point for a digital timer.

  14. Digital ac monitor

    DOEpatents

    Hart, G.W.; Kern, E.C. Jr.

    1987-06-09

    An apparatus and method is provided for monitoring a plurality of analog ac circuits by sampling the voltage and current waveform in each circuit at predetermined intervals, converting the analog current and voltage samples to digital format, storing the digitized current and voltage samples and using the stored digitized current and voltage samples to calculate a variety of electrical parameters; some of which are derived from the stored samples. The non-derived quantities are repeatedly calculated and stored over many separate cycles then averaged. The derived quantities are then calculated at the end of an averaging period. This produces a more accurate reading, especially when averaging over a period in which the power varies over a wide dynamic range. Frequency is measured by timing three cycles of the voltage waveform using the upward zero crossover point as a starting point for a digital timer. 24 figs.

  15. Virtual welding equipment for simulation of GMAW processes with integration of power source regulation

    NASA Astrophysics Data System (ADS)

    Reisgen, Uwe; Schleser, Markus; Mokrov, Oleg; Zabirov, Alexander

    2011-06-01

    A two dimensional transient numerical analysis and computational module for simulation of electrical and thermal characteristics during electrode melting and metal transfer involved in Gas-Metal-Arc-Welding (GMAW) processes is presented. Solution of non-linear transient heat transfer equation is carried out using a control volume finite difference technique. The computational module also includes controlling and regulation algorithms of industrial welding power sources. The simulation results are the current and voltage waveforms, mean voltage drops at different parts of circuit, total electric power, cathode, anode and arc powers and arc length. We describe application of the model for normal process (constant voltage) and for pulsed processes with U/I and I/I-modulation modes. The comparisons with experimental waveforms of current and voltage show that the model predicts current, voltage and electric power with a high accuracy. The model is used in simulation package SimWeld for calculation of heat flux into the work-piece and the weld seam formation. From the calculated heat flux and weld pool sizes, an equivalent volumetric heat source according to Goldak model, can be generated. The method was implemented and investigated with the simulation software SimWeld developed by the ISF at RWTH Aachen University.

  16. An underground nuclear power station using self-regulating heat-pipe controlled reactors

    DOEpatents

    Hampel, V.E.

    1988-05-17

    A nuclear reactor for generating electricity is disposed underground at the bottom of a vertical hole that can be drilled using conventional drilling technology. The primary coolant of the reactor core is the working fluid in a plurality of thermodynamically coupled heat pipes emplaced in the hole between the heat source at the bottom of the hole and heat exchange means near the surface of the earth. Additionally, the primary coolant (consisting of the working fluid in the heat pipes in the reactor core) moderates neutrons and regulates their reactivity, thus keeping the power of the reactor substantially constant. At the end of its useful life, the reactor core may be abandoned in place. Isolation from the atmosphere in case of accident or for abandonment is provided by the operation of explosive closures and mechanical valves emplaced along the hole. This invention combines technology developed and tested for small, highly efficient, space-based nuclear electric power plants with the technology of fast- acting closure mechanisms developed and used for underground testing of nuclear weapons. This invention provides a nuclear power installation which is safe from the worst conceivable reactor accident, namely, the explosion of a nuclear weapon near the ground surface of a nuclear power reactor. 5 figs.

  17. Underground nuclear power station using self-regulating heat-pipe controlled reactors

    DOEpatents

    Hampel, Viktor E.

    1989-01-01

    A nuclear reactor for generating electricity is disposed underground at the bottom of a vertical hole that can be drilled using conventional drilling technology. The primary coolant of the reactor core is the working fluid in a plurality of thermodynamically coupled heat pipes emplaced in the hole between the heat source at the bottom of the hole and heat exchange means near the surface of the earth. Additionally, the primary coolant (consisting of the working flud in the heat pipes in the reactor core) moderates neutrons and regulates their reactivity, thus keeping the power of the reactor substantially constant. At the end of its useful life, the reactor core may be abandoned in place. Isolation from the atmosphere in case of accident or for abandonment is provided by the operation of explosive closures and mechanical valves emplaced along the hole. This invention combines technology developed and tested for small, highly efficient, space-based nuclear electric power plants with the technology of fast-acting closure mechanisms developed and used for underground testing of nuclear weapons. This invention provides a nuclear power installation which is safe from the worst conceivable reactor accident, namely, the explosion of a nuclear weapon near the ground surface of a nuclear power reactor.

  18. Halbach array generator/motor having mechanically regulated output voltage and mechanical power output

    SciTech Connect

    Post, Richard F.

    2005-06-14

    A motor/generator has its stationary portion, i.e., the stator, positioned concentrically within its rotatable element, i.e., the rotor, along the axis of rotation of the rotor. The rotor includes a Halbach array of magnets. The voltage and power outputs are regulated by varying the radial gap in between the stator windings and the rotating Halbach array. The gap is varied by extensible and retractable supports attached to the stator windings that can move the windings in a radial direction.

  19. Microcomputer technology applications: Charger and regulator software for a breadboard programmable power processor

    NASA Technical Reports Server (NTRS)

    Green, D. M.

    1978-01-01

    Software programs are described, one which implements a voltage regulation function, and one which implements a charger function with peak-power tracking of its input. The software, written in modular fashion, is intended as a vehicle for further experimentation with the P-3 system. A control teleprinter allows an operator to make parameter modifications to the control algorithm during experiments. The programs require 3K ROM and 2K ram each. User manuals for each system are included as well as a third program for simple I/O control.

  20. Halbach array generator/motor having an automatically regulated output voltage and mechanical power output

    DOEpatents

    Post, Richard F.

    2005-02-22

    A motor/generator having its stationary portion, i.e., the stator, positioned concentrically within its rotatable element, i.e., the rotor, along its axis of rotation. The rotor includes a Halbach array. The stator windings are switched or commutated to provide a DC motor/generator much the same as in a conventional DC motor/generator. The voltage and power are automatically regulated by using centrifugal force to change the diameter of the rotor, and thereby vary the radial gap in between the stator and the rotating Halbach array, as a function of the angular velocity of the rotor.

  1. Coordinated control of wind generation and energy storage for power system frequency regulation

    NASA Astrophysics Data System (ADS)

    Baone, Chaitanya Ashok

    Large-scale centralized synchronous generators have long been the primary actors in exercising active power and frequency control, and much of the existing grid control framework is predicated upon their dynamic terminal characteristics. Important among these characteristics is the inertia of such generators. These play key roles in determining the electromechanical stability of the electric power grid. Modern wind generator systems are partially or fully connected to the grid through power electronic interfaces, and hence do not present the same level of inertial coupling. The absence of inertial frequency response from modern wind generator systems is a topic of growing concern in power engineering practice, as the penetration of wind generation is expected to grow dramatically in the next few years. Solutions proposed in the literature have sought to address this problem by seeking to mimic the inherent inertial response characteristics of traditional synchronous generators via control loops added to wind generators. Recent literature has raised concerns regarding this approach, and the work here will further examine its shortcomings, motivating approaches that seek to optimally design for the characteristics of the equipment exercising the control, rather than forcing new technologies to mimic the characteristics of synchronous machines. In particular, this work will develop a new approach to power system frequency regulation, with features suited to distributed energy storage devices such as grid-scale batteries and wind turbine speed and blade pitch control. The dynamic characteristics of these new technologies are treated along with existing mechanisms, such as synchronous machine governor control, to develop a comprehensive multi-input control design approach. To make the method practically feasible for geographically distributed power systems, an observer-based distributed control design utilizing phasor measurement unit (PMU) signals along with local

  2. Dynamic power flow controllers

    DOEpatents

    Divan, Deepakraj M.; Prasai, Anish

    2017-03-07

    Dynamic power flow controllers are provided. A dynamic power flow controller may comprise a transformer and a power converter. The power converter is subject to low voltage stresses and not floated at line voltage. In addition, the power converter is rated at a fraction of the total power controlled. A dynamic power flow controller controls both the real and the reactive power flow between two AC sources having the same frequency. A dynamic power flow controller inserts a voltage with controllable magnitude and phase between two AC sources; thereby effecting control of active and reactive power flows between two AC sources.

  3. Suppression of AcMNPV replication by adf and thymosin protein up-regulation in a new testis cell line, Ha-shl-t

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Host cytoskeletons facilitate the entry, replication and egress of viruses; because cytoskeletons are essential for viral survival, one mechanism of resisting viral infections involves regulating cytoskeletal polymerization/depolymerization. However, the molecular mechanisms of regulating these chan...

  4. The Optimisation Of Array Power Regulators (APRS) For Solar Observation Platforms And Future Electrical Power System (EPS) Through The B2R Topology

    NASA Astrophysics Data System (ADS)

    Alcindor, Peter; Bard, Frederic; Kiewe, Bernhard; Tonicello, Ferdinando; Mourra, Oliver

    2011-10-01

    Power regulators for solar observation platforms must be compatible with widely varying solar array voltages due to the large temperature variations resulting from contrasting sun distances or sun/eclipse cycling close to the sun. To produce a 28V regulated power bus for scientific instruments a Buck topology is necessary (today's qualified technology). Analysis will show that front end of Power Conditioning Units (PCUs) must work over voltage ranges of almost twice that of Earth orbiting spacecraft. This paper is targeted at missions that operate over the full mission trajectory and in particular at far sun distances where array sizing is performed. Performance degradation associated with Buck topologies operating over wide voltage ranges is established and the importance of reducing the solar array voltage to a minimum is highlighted. Finally, attention is drawn to how the Buck-Boost Regulator (B2R) topology, currently under development, provides a potential solution to this and other problems.

  5. Single Event Transients in Voltage Regulators for FPGA Power Supply Applications

    NASA Technical Reports Server (NTRS)

    Poivey, Christian; Sanders, Anthony; Kim, Hak; Phan, Anthony; Forney, Jim; LaBel, Kenneth A.; Karsh, Jeremy; Pursley, Scott; Kleyner, Igor; Katz, Richard

    2006-01-01

    As with other bipolar analog devices, voltage regulators are known to be sensitive to single event transients (SET). In typical applications, large output capacitors are used to provide noise immunity. Therefore, since SET amplitude and duration are generally small, they are often of secondary importance due to this capacitance filtering. In low voltage applications, however, even small SET are a concern. Over-voltages may cause destructive conditions. Under-voltages may cause functional interrupts and may also trigger electrical latchup conditions. In addition, internal protection circuits which are affected by load as well as internal thermal effects can also be triggered from heavy ions, causing dropouts or shutdown ranging from milliseconds to seconds. In the case of FPGA power supplies applications, SETS are critical. For example, in the case of Actel FPGA RTAX family, core power supply voltage is 1.5V. Manufacturer specifies an absolute maximum rating of 1.6V and recommended operating conditions between 1.425V and 1.575V. Therefore, according to the manufacturer, any transient of amplitude greater than 75 mV can disrupt normal circuit functions, and overvoltages greater than 100 mV may damage the FPGA. We tested five low dropout voltage regulators for SET sensitivity under a large range of circuit application conditions.

  6. Adaptive PI controller to voltage regulation in power systems: STATCOM as a case study.

    PubMed

    Tavana, Mohammad Reza; Khooban, Mohammad-Hassan; Niknam, Taher

    2017-01-01

    Static synchronous compensator (STATCOM) provides the means to improve quality and reliability of a power system as it has the functional capability to handle dynamic disturbances, such as transient stability and power oscillation damping as well as to providing voltage regulation. In this paper, a robust adaptive PI-based optimal fuzzy control strategy is proposed to control a STATCOM used in distribution systems. The proposed intelligent strategy is based on a combination of a new General Type-II Fuzzy Logic (GT2FL) with a simple heuristic algorithm named Teaching Learning Based Optimization (TLBO) Algorithm. The proposed framework optimally tunes parameters of a Proportional-Integral (PI) controller which, similar to most of other researchers regarding control of STATCOM, are in charge of controlling the device. The proposed controller guaranties robustness and stability against uncertainties caused by external disturbances or ever-changing nature of the power systems. The TLBO optimizes the parameters of the controller as well as the input and output membership functions. To validate the efficiency of the proposed controller, the obtained simulation results are compared with those of the two most recent researches applied in this field, namely, conventional Proportional Integral (PI) controller and Optimal Fuzzy PI (OFPI) controller. Results demonstrate the successfulness and effectiveness of the proposed online-TLBO General Type-2 Fuzzy PI (OGT2FPI) controller and its superiority over conventional approaches.

  7. The AC-120: The advanced commercial transport

    NASA Technical Reports Server (NTRS)

    Duran, David; Griffin, Ernest; Mendoza, Saul; Nguyen, Son; Pickett, Tim; Noernberg, Clemm

    1993-01-01

    The main objective of this design was to fulfill a need for a new airplane to replace the aging 100 to 150 passenger, 1500 nautical mile range aircraft such as the Douglas DC9 and Boeing 737-100 airplanes. After researching the future aircraft market, conducting extensive trade studies, and analysis on different configurations, the AC-120 Advanced Commercial Transport final design was achieved. The AC-120's main design features include the incorporation of a three lifting surface configuration which is powered by two turboprop engines. The AC-120 is an economically sensitive aircraft which meets the new FM Stage Three noise requirements, and has lower NO(x) emissions than current turbofan powered airplanes. The AC-120 also improves on its contemporaries in passenger comfort, manufacturing, and operating cost.

  8. CD133 protein N-glycosylation processing contributes to cell surface recognition of the primitive cell marker AC133 epitope.

    PubMed

    Mak, Anthony B; Blakely, Kim M; Williams, Rashida A; Penttilä, Pier-Andrée; Shukalyuk, Andrey I; Osman, Khan T; Kasimer, Dahlia; Ketela, Troy; Moffat, Jason

    2011-11-25

    The AC133 epitope expressed on the CD133 glycoprotein has been widely used as a cell surface marker of numerous stem cell and cancer stem cell types. It has been recently proposed that posttranslational modification and regulation of CD133 may govern cell surface AC133 recognition. Therefore, we performed a large scale pooled RNA interference (RNAi) screen to identify genes involved in cell surface AC133 expression. Gene hits could be validated at a rate of 70.5% in a secondary assay using an orthogonal RNAi system, demonstrating that our primary RNAi screen served as a powerful genetic screening approach. Within the list of hits from the primary screen, genes involved in N-glycan biosynthesis were significantly enriched as determined by Ingenuity Canonical Pathway analyses. Indeed, inhibiting biosynthesis of the N-glycan precursor using the small molecule tunicamycin or inhibiting its transfer to CD133 by generating N-glycan-deficient CD133 mutants resulted in undetectable cell surface AC133. Among the screen hits involved in N-glycosylation were genes involved in complex N-glycan processing, including the poorly characterized MGAT4C, which we demonstrate to be a positive regulator of cell surface AC133 expression. Our study identifies a set of genes involved in CD133 N-glycosylation as a direct contributing factor to cell surface AC133 recognition and provides biochemical evidence for the function and structure of CD133 N-glycans.

  9. Unity power factor converter

    NASA Technical Reports Server (NTRS)

    Wester, Gene W. (Inventor)

    1980-01-01

    A unity power factor converter capable of effecting either inversion (dc-to-dc) or rectification (ac-to-dc), and capable of providing bilateral power control from a DC source (or load) through an AC transmission line to a DC load (or source) for power flow in either direction, is comprised of comparators for comparing the AC current i with an AC signal i.sub.ref (or its phase inversion) derived from the AC ports to generate control signals to operate a switch control circuit for high speed switching to shape the AC current waveform to a sine waveform, and synchronize it in phase and frequency with the AC voltage at the AC ports, by selectively switching the connections to a series inductor as required to increase or decrease the current i.

  10. ACS: ALMA Common Software

    NASA Astrophysics Data System (ADS)

    Chiozzi, Gianluca; Šekoranja, Matej

    2013-02-01

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

  11. A Decentralized Multivariable Robust Adaptive Voltage and Speed Regulator for Large-Scale Power Systems

    NASA Astrophysics Data System (ADS)

    Okou, Francis A.; Akhrif, Ouassima; Dessaint, Louis A.; Bouchard, Derrick

    2013-05-01

    This papter introduces a decentralized multivariable robust adaptive voltage and frequency regulator to ensure the stability of large-scale interconnnected generators. Interconnection parameters (i.e. load, line and transormer parameters) are assumed to be unknown. The proposed design approach requires the reformulation of conventiaonal power system models into a multivariable model with generator terminal voltages as state variables, and excitation and turbine valve inputs as control signals. This model, while suitable for the application of modern control methods, introduces problems with regards to current design techniques for large-scale systems. Interconnection terms, which are treated as perturbations, do not meet the common matching condition assumption. A new adaptive method for a certain class of large-scale systems is therefore introduces that does not require the matching condition. The proposed controller consists of nonlinear inputs that cancel some nonlinearities of the model. Auxiliary controls with linear and nonlinear components are used to stabilize the system. They compensate unknown parametes of the model by updating both the nonlinear component gains and excitation parameters. The adaptation algorithms involve the sigma-modification approach for auxiliary control gains, and the projection approach for excitation parameters to prevent estimation drift. The computation of the matrix-gain of the controller linear component requires the resolution of an algebraic Riccati equation and helps to solve the perturbation-mismatching problem. A realistic power system is used to assess the proposed controller performance. The results show that both stability and transient performance are considerably improved following a severe contingency.

  12. Coal-fired power generaion, new air quality regulations, and future U.S. coal production

    USGS Publications Warehouse

    Attanasi, E.D.; Root, D.H.

    1999-01-01

    Tighter new regulation of stack gas emissions and competition in power generation are driving electrical utilities to demand cleaner, lower sulfur coal. Historical data on sulfur content of produced coals shows little variability in coal quality for individual mines and individual coal-producing counties over relatively long periods of time. If coal-using power generators follow the compliance patterns established in Phase I of the 1990 Clean Air Act Amendments, then the industry's response to the tighter Phase II emissions standards will result in large amounts of coal production shifting from higher sulfur areas to areas with lower cost low sulfur coal. One reason this shift will likely occur is that currently only 30% of U.S. coal-fired electrical generating capacity is equipped with flue-gas scrubbers. In 1995, coal mines in the higher sulfur areas of the Illinois Basin and Northern and Central Appalachia employed 78% of all coal miners (>70,000 miners). A substantial geographical redistribution of the nation's coal supplies will likely lead to economic dislocations that will reach beyond local coal-producing areas.

  13. Regulation of cellular marker modulated upon irradiation of low power laser light in burn injured mice

    NASA Astrophysics Data System (ADS)

    Rathnakar, Bharath; Prabhu, Vijendra; Rao, Bola Sadashiva Satish; Chandra, Subhash; Rai, Sharada; Mahato, Krishna Kishore

    2016-12-01

    The present study intends to understand the importance of cellular marker in tissue regeneration regulated upon irradiation of low power laser light in burn inflicted mice. Under anesthetic conditions, the thermal injury was induced on Swiss albino mice of either sex. Following injury, the animals were randomly divided into three groups; i. e., un-illuminated control, the group treated with 5% Povidone iodine (reference standard) and single exposure of 3 J/cm2 (830 nm). Burn tissue samples from each group were excised at day 6 post burn injury upon euthanization and used for histological and immunohistochemical analysis. Haematoxylin and Eosin (H and E) staining was performed on the selected sections to asses proliferation and angiogenesis at day 6 post-injury. For immunohistochemical analysis, tissue sections from all the three treatment groups on day 6 were stained using specific antibody against Proliferating cell nuclear antigen (PCNA). The results of the histological and immunohistochemical analysis showed improved tissue restoration in animals treated with optimal laser influence as compared to un-illuminated controls. The findings of present study clearly demonstrated the beneficial effects of 830 nm laser in burn wound healing and its influence in regulating the cellular marker.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Technical Reports Server (NTRS)

    Lipo, Thomas A.; Alan, Irfan

    1991-01-01

    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

  16. Fast regulation of AP-1 activity through interaction of lamin A/C, ERK1/2, and c-Fos at the nuclear envelope

    PubMed Central

    González, José María; Navarro-Puche, Ana; Casar, Berta; Crespo, Piero; Andrés, Vicente

    2008-01-01

    Sequestration of c-Fos at the nuclear envelope (NE) through interaction with A-type lamins suppresses AP-1–dependent transcription. We show here that c-Fos accumulation within the extraction-resistant nuclear fraction (ERNF) and its interaction with lamin A are reduced and enhanced by gain-of and loss-of ERK1/2 activity, respectively. Moreover, hindering ERK1/2-dependent phosphorylation of c-Fos attenuates its release from the ERNF induced by serum and promotes its interaction with lamin A. Accordingly, serum stimulation rapidly releases preexisting c-Fos from the NE via ERK1/2-dependent phosphorylation, leading to a fast activation of AP-1 before de novo c-Fos synthesis. Moreover, lamin A–null cells exhibit increased AP-1 activity and reduced levels of c-Fos phosphorylation. We also find that active ERK1/2 interacts with lamin A and colocalizes with c-Fos and A-type lamins at the NE. Thus, NE-bound ERK1/2 functions as a molecular switch for rapid mitogen-dependent AP-1 activation through phosphorylation-induced release of preexisting c-Fos from its inhibitory interaction with lamin A/C. PMID:19015316

  17. Glutaminolysis Was Induced by TGF-β1 through PP2Ac Regulated Raf-MEK-ERK Signaling in Endothelial Cells.

    PubMed

    Guo, YanYan; Deng, YuanJun; Li, XiaoQing; Ning, Yong; Lin, XuePing; Guo, ShuiMing; Chen, MeiXue; Han, Min

    2016-01-01

    Vascular endothelial cells can survive under hypoxic and inflammatory conditions by alterations of the cellular energy metabolism. In addition to high rates of glycolysis, glutaminolysis is another important way of providing the required energy to support cellular sprouting in such situations. However, the exact mechanism in which endothelial cells upregulate glutaminolysis remains unclear. Here we demonstrated that protein phosphatase 2A (PP2A)-mediated Raf-MEK-ERK signaling was involved in glutaminolysis in endothelial cells. Using models of human umbilical vein endothelial cells (HUVECs) treated with transforming growth factor-β1 (TGF-β1), we observed a dramatic induction in cellular glutamate levels accompanied by Raf-MEK-ERK activation. By addition of U0126, the specific inhibitor of MEK1/2, the expression of kidney-type glutaminase (KGA, a critical glutaminase in glutaminolysis) was significantly decreased. Moreover, inhibition of PP2A by okadaic acid (OA), a specific inhibitor of PP2A phosphatase activity or by depletion of its catalytic subunit (PP2Ac), led to a significant inactivation of Raf-MEK-ERK signaling and reduced glutaminolysis in endothelial cells. Taken together, these results indicated that PP2A-dependent Raf-MEK-ERK activation was involved in glutaminolysis and inhibition of PP2A signals was sufficient to block Raf-MEK-ERK pathway and reduced glutamine metabolism in endothelial cells.

  18. Glutaminolysis Was Induced by TGF-β1 through PP2Ac Regulated Raf-MEK-ERK Signaling in Endothelial Cells

    PubMed Central

    Li, XiaoQing; Ning, Yong; Lin, XuePing; Guo, ShuiMing; Chen, MeiXue; Han, Min

    2016-01-01

    Vascular endothelial cells can survive under hypoxic and inflammatory conditions by alterations of the cellular energy metabolism. In addition to high rates of glycolysis, glutaminolysis is another important way of providing the required energy to support cellular sprouting in such situations. However, the exact mechanism in which endothelial cells upregulate glutaminolysis remains unclear. Here we demonstrated that protein phosphatase 2A (PP2A)-mediated Raf-MEK-ERK signaling was involved in glutaminolysis in endothelial cells. Using models of human umbilical vein endothelial cells (HUVECs) treated with transforming growth factor-β1 (TGF-β1), we observed a dramatic induction in cellular glutamate levels accompanied by Raf-MEK-ERK activation. By addition of U0126, the specific inhibitor of MEK1/2, the expression of kidney-type glutaminase (KGA, a critical glutaminase in glutaminolysis) was significantly decreased. Moreover, inhibition of PP2A by okadaic acid (OA), a specific inhibitor of PP2A phosphatase activity or by depletion of its catalytic subunit (PP2Ac), led to a significant inactivation of Raf-MEK-ERK signaling and reduced glutaminolysis in endothelial cells. Taken together, these results indicated that PP2A-dependent Raf-MEK-ERK activation was involved in glutaminolysis and inhibition of PP2A signals was sufficient to block Raf-MEK-ERK pathway and reduced glutamine metabolism in endothelial cells. PMID:27612201

  19. Power supply

    DOEpatents

    Yakymyshyn, Christopher Paul; Hamilton, Pamela Jane; Brubaker, Michael Allen

    2007-12-04

    A modular, low weight impedance dropping power supply with battery backup is disclosed that can be connected to a high voltage AC source and provide electrical power at a lower voltage. The design can be scaled over a wide range of input voltages and over a wide range of output voltages and delivered power.

  20. Effect on the condition of the metal in A K-300-3.5 turbine owing to multicycle fatigue from participation of a power generating unit in grid frequency and power regulation

    SciTech Connect

    Lebedeva, A. I.; Zorchenko, N. V.; Prudnikov, A. A.

    2011-09-15

    The effect on the condition of the rotor material owing to multicycle fatigue caused by variable stresses during participation of a power generating unit in grid frequency and power regulation is evaluated using the K-300-23.5 steam turbine as an example. It is shown that during normalized primary frequency regulation the safety factor is at least 50, while during automatic secondary regulation of frequency and power there is essentially no damage to the metal.

  1. tACS Phase Locking of Frontal Midline Theta Oscillations Disrupts Working Memory Performance

    PubMed Central

    Chander, Bankim S.; Witkowski, Matthias; Braun, Christoph; Robinson, Stephen E.; Born, Jan; Cohen, Leonardo G.; Birbaumer, Niels; Soekadar, Surjo R.

    2016-01-01

    Background: Frontal midline theta (FMT) oscillations (4–8 Hz) are strongly related to cognitive and executive control during mental tasks such as memory processing, arithmetic problem solving or sustained attention. While maintenance of temporal order information during a working memory (WM) task was recently linked to FMT phase, a positive correlation between FMT power, WM demand and WM performance was shown. However, the relationship between these measures is not well understood, and it is unknown whether purposeful FMT phase manipulation during a WM task impacts FMT power and WM performance. Here we present evidence that FMT phase manipulation mediated by transcranial alternating current stimulation (tACS) can block WM demand-related FMT power increase (FMTΔpower) and disrupt normal WM performance. Methods: Twenty healthy volunteers were assigned to one of two groups (group A, group B) and performed a 2-back task across a baseline block (block 1) and an intervention block (block 2) while 275-sensor magnetoencephalography (MEG) was recorded. After no stimulation was applied during block 1, participants in group A received tACS oscillating at their individual FMT frequency over the prefrontal cortex (PFC) while group B received sham stimulation during block 2. After assessing and mapping phase locking values (PLV) between the tACS signal and brain oscillatory activity across the whole brain, FMT power and WM performance were assessed and compared between blocks and groups. Results: During block 2 of group A but not B, FMT oscillations showed increased PLV across task-related cortical areas underneath the frontal tACS electrode. While WM task-related FMTΔpower and WM performance were comparable across groups in block 1, tACS resulted in lower FMTΔpower and WM performance compared to sham stimulation in block 2. Conclusion: tACS-related manipulation of FMT phase can disrupt WM performance and influence WM task-related FMTΔpower. This finding may have important

  2. Regulation and deregulation of cholesterol homeostasis: The liver as a metabolic “power station”

    PubMed Central

    Trapani, Laura; Segatto, Marco; Pallottini, Valentina

    2012-01-01

    Cholesterol plays several structural and metabolic roles that are vital for human biology. It spreads along the entire plasma membrane of the cell, modulating fluidity and concentrating in specialized sphingolipid-rich domains called rafts and caveolae. Cholesterol is also a substrate for steroid hormones. However, too much cholesterol can lead to pathological pictures such as atherosclerosis, which is a consequence of the accumulation of cholesterol into the cells of the artery wall. The liver is considered to be the metabolic power station of mammalians, where cholesterol homeostasis relies on an intricate network of cellular processes whose deregulations can lead to several life-threatening pathologies, such as familial and age-related hypercholesterolemia. Cholesterol homeostasis maintenance is carried out by: biosynthesis, via 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity; uptake, through low density lipoprotein receptors (LDLr); lipoprotein release in the blood; storage by esterification; and degradation and conversion into bile acids. Both HMGR and LDLr are transcribed as a function of cellular sterol amount by a family of transcription factors called sterol regulatory element binding proteins that are responsible for the maintenance of cholesterol homeostasis through an intricate mechanism of regulation. Cholesterol obtained by hepatic de novo synthesis can be esterified and incorporated into apolipoprotein B-100-containing very low density lipoproteins, which are then secreted into the bloodstream for transport to peripheral tissues. Moreover, dietary cholesterol is transferred from the intestine to the liver by high density lipoproteins (HDLs); all HDL particles are internalized in the liver, interacting with the hepatic scavenger receptor (SR-B1). Here we provide an updated overview of liver cholesterol metabolism regulation and deregulation and the causes of cholesterol metabolism-related diseases. Moreover, current pharmacological

  3. Regulation and deregulation of cholesterol homeostasis: The liver as a metabolic "power station".

    PubMed

    Trapani, Laura; Segatto, Marco; Pallottini, Valentina

    2012-06-27

    Cholesterol plays several structural and metabolic roles that are vital for human biology. It spreads along the entire plasma membrane of the cell, modulating fluidity and concentrating in specialized sphingolipid-rich domains called rafts and caveolae. Cholesterol is also a substrate for steroid hormones. However, too much cholesterol can lead to pathological pictures such as atherosclerosis, which is a consequence of the accumulation of cholesterol into the cells of the artery wall. The liver is considered to be the metabolic power station of mammalians, where cholesterol homeostasis relies on an intricate network of cellular processes whose deregulations can lead to several life-threatening pathologies, such as familial and age-related hypercholesterolemia. Cholesterol homeostasis maintenance is carried out by: biosynthesis, via 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity; uptake, through low density lipoprotein receptors (LDLr); lipoprotein release in the blood; storage by esterification; and degradation and conversion into bile acids. Both HMGR and LDLr are transcribed as a function of cellular sterol amount by a family of transcription factors called sterol regulatory element binding proteins that are responsible for the maintenance of cholesterol homeostasis through an intricate mechanism of regulation. Cholesterol obtained by hepatic de novo synthesis can be esterified and incorporated into apolipoprotein B-100-containing very low density lipoproteins, which are then secreted into the bloodstream for transport to peripheral tissues. Moreover, dietary cholesterol is transferred from the intestine to the liver by high density lipoproteins (HDLs); all HDL particles are internalized in the liver, interacting with the hepatic scavenger receptor (SR-B1). Here we provide an updated overview of liver cholesterol metabolism regulation and deregulation and the causes of cholesterol metabolism-related diseases. Moreover, current pharmacological

  4. Mercury emission trend influenced by stringent air pollutants regulation for coal-fired power plants in Korea

    NASA Astrophysics Data System (ADS)

    Pudasainee, Deepak; Kim, Jeong-Hun; Seo, Yong-Chil

    2009-12-01

    Regulatory control of mercury emission from anthropogenic sources has become a global concern in the recent past. Coal-fired power plants are one of the largest sources of anthropogenic mercury emission into the atmosphere. This paper summarizes the current reducing trend of mercury emission as co-beneficial effect by more stringent regulation changes to control primary air pollutants with introducing test results from the commercial coal-fired facilities and suggesting a guideline for future regulatory development in Korea. On average, mercury emission concentrations ranged 16.3-2.7 μg Sm -3, 2.4-1.1 μg Sm -3, 3.1-0.7 μg Sm -3 from anthracite coal-fired power plants equipped with electrostatic precipitator (ESP), bituminous coal-fired power plants with ESP + flue gas desulphurization (FGD) and bituminous coal-fired power plants with selective catalytic reactor (SCR) + cold side (CS) - ESP + wet FGD, respectively. Among the existing air pollution control devices, the best configuration for mercury removal in coal-fired power plants was SCR + CS - ESP + wet FGD, which were installed due to the stringent regulation changes to control primary air pollutants emission such as SO 2, NOx and dust. It was estimated that uncontrolled and controlled mercury emission from coal-fired power plants as 10.3 ton yr -1 and 3.2 ton yr -1 respectively. After the installation of ESP, FGD and SCR system, following the enforcement of the stringent regulation, 7.1 ton yr -1 of mercury emission has been reduced (nearly 69%) from coal-fired power plants as a co-benefit control. Based on the overall study, a sample guideline including emission limits were suggested which will be applied to develop a countermeasure for controlling mercury emission from coal-fired power plants.

  5. 76 FR 67259 - Frequency Regulation Compensation in the Organized Wholesale Power Markets

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-31

    ... electric markets and ensure that providers of frequency regulation receive just and reasonable and not... regulation in the organized wholesale electric markets and ensure that providers of frequency regulation... network pilot programs before requiring a revision of frequency regulation service.\\46\\ \\46\\ EEI May...

  6. Microfabricated AC impedance sensor

    DOEpatents

    Krulevitch, Peter; Ackler, Harold D.; Becker, Frederick; Boser, Bernhard E.; Eldredge, Adam B.; Fuller, Christopher K.; Gascoyne, Peter R. C.; Hamilton, Julie K.; Swierkowski, Stefan P.; Wang, Xiao-Bo

    2002-01-01

    A microfabricated instrument for detecting and identifying cells and other particles based on alternating current (AC) impedance measurements. The microfabricated AC impedance sensor includes two critical elements: 1) a microfluidic chip, preferably of glass substrates, having at least one microchannel therein and with electrodes patterned on both substrates, and 2) electrical circuits that connect to the electrodes on the microfluidic chip and detect signals associated with particles traveling down the microchannels. These circuits enable multiple AC impedance measurements of individual particles at high throughput rates with sufficient resolution to identify different particle and cell types as appropriate for environmental detection and clinical diagnostic applications.

  7. Power electronics for low power arcjets

    NASA Technical Reports Server (NTRS)

    Hamley, John A.; Hill, Gerald M.

    1991-01-01

    In anticipation of the needs of future light-weight, low-power spacecraft, arcjet power electronics in the 100 to 400 W operating range were developed. Limited spacecraft power and thermal control capacity of these small spacecraft emphasized the need for high efficiency. Power topologies similar to those in the higher 2 kW and 5 to 30 kW power range were implemented, including a four transistor bridge switching circuit, current mode pulse-width modulated control, and an output current averaging inductor with an integral pulse generation winding. Reduction of switching transients was accomplished using a low inductance power distribution network, and no passive snubber circuits were necessary for power switch protection. Phase shift control of the power bridge was accomplished using an improved pulse width modulation to phase shift converter circuit. These features, along with conservative magnetics designs allowed power conversion efficiencies of greater than 92.5 percent to be achieved into resistive loads over the entire operating range of the converter. Electromagnetic compatibility requirements were not considered in this work, and control power for the converter was derived from AC mains. Addition of input filters and control power converters would result in an efficiency of on the order of 90 percent for a flight unit. Due to the developmental nature of arcjet systems at this power level, the exact nature of the thruster/power processor interface was not quantified. Output regulation and current ripple requirements of 1 and 20 percent respectively, as well as starting techniques, were derived from the characteristics of the 2 kW system but an open circuit voltage in excess of 175 V was specified. Arcjet integration tests were performed, resulting in successful starts and stable arcjet operation at power levels as low as 240 W with simulated hydrazine propellants.

  8. New Methodology for Evaluating Optimal Pricing for Primary Regulation of Deregulated Power Systems under Steady State Condition

    NASA Astrophysics Data System (ADS)

    Satyaramesh, P. V.; RadhaKrishna, C.

    2013-06-01

    A generalized pricing structure for procurement of power under frequency ancillary service is developed in this paper. It is a frequency linked-price model and suitable for deregulation market environment. This model takes into consideration: governor characteristics and frequency characteristics of generator as additional parameters in load flow method. The main objective of the new approach proposed in this paper is to establish bidding price structure for frequency regulation services in competitive ancillary electrical markets under steady state condition. Lot of literatures are available for calculating the frequency deviations with respect to load changes by using dynamic simulation methods. But in this paper, the model computes the frequency deviations for additional requirements of power under steady state with considering power system network topology. An attempt is also made in this paper to develop optimal bidding price structure for the frequency-regulated systems. It gives a signal to traders or bidders that the power demand can be assessed more accurately much closer to real time and helps participants bid more accurate quantities on day-ahead market. The recent trends of frequency linked-price model existing in Indian power systems issues required for attention are also dealt in this paper. Test calculations have been performed on 30-bus system. The paper also explains adoptability of 33 this model to practical Indian power system. The results presented are analyzed and useful conclusions are drawn.

  9. Solid-state ac-to-dc converter

    NASA Technical Reports Server (NTRS)

    Monroe, C. M.

    1970-01-01

    Converter uses solid-state ac-to-dc rectification circuitry, filter circuitry, a tuned transformer, ac chopper circuitry, and an automatic current-control network. It has a dc power source which operates from 5 to 100 percent load at a 72 to 94 input to output efficiency.

  10. Microtubule alignment and manipulation using AC electrokinetics.

    PubMed

    Uppalapati, Maruti; Huang, Ying-Ming; Jackson, Thomas N; Hancock, William O

    2008-09-01

    The kinesin-microtubule system plays an important role in intracellular transport and is a model system for integrating biomotor-driven transport into microengineered devices. AC electrokinetics provides a novel tool for manipulating and organizing microtubules in solution, enabling new experimental geometries for investigating and controlling the interactions of microtubules and microtubule motors in vitro. By fabricating microelectrodes on glass substrates and generating AC electric fields across solutions of microtubules in low-ionic-strength buffers, bundles of microtubules are collected and aligned and the electrical properties of microtubules in solution are measured. The AC electric fields result in electro-osmotic flow, electrothermal flow, and dielectrophoresis of microtubules, which can be controlled by varying the solution conductivity, AC frequency, and electrode geometry. By mapping the solution conductivity and AC frequency over which positive dielectrophoresis occurs, the apparent conductivity of taxol-stabilized bovine-brain microtubules in PIPES buffer is measured to be 250 mS m(-1). By maximizing dielectrophoretic forces and minimizing electro-osmotic and electrothermal flow, microtubules are assembled into opposed asters. These experiments demonstrate that AC electrokinetics provides a powerful new tool for kinesin-driven transport applications and for investigating the role of microtubule motors in development and maintenance of the mitotic spindle.

  11. A novel power converter for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Yuvarajan, S.; Yu, Dachuan; Xu, Shanguang

    A simple and economical power conditioner to convert the power available from solar panels into 60 Hz ac voltage is described. The raw dc voltage from the solar panels is converted to a regulated dc voltage using a boost converter and a large capacitor and the dc output is then converted to 60 Hz ac using a bridge inverter. The ratio between the load current and the short-circuit current of a PV panel at maximum power point is nearly constant for different insolation (light) levels and this property is utilized in designing a simple maximum power point tracking (MPPT) controller. The controller includes a novel arrangement for sensing the short-circuit current without disturbing the operation of the PV panel and implementing MPPT. The switching losses in the inverter are reduced by using snubbers. The results obtained on an experimental converter are presented.

  12. 40 CFR Appendixes A-C to Part 403 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 30 2013-07-01 2012-07-01 true A Appendixes A-C to Part 403 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PRETREATMENT REGULATIONS FOR EXISTING AND NEW SOURCES OF POLLUTION Appendixes A-C to Part 403...

  13. 34 CFR Appendices A-C to Part 682 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 4 2014-07-01 2014-07-01 false A Appendices A-C to Part 682 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION (CONTINUED) FEDERAL FAMILY EDUCATION LOAN (FFEL) PROGRAM Appendices A-C to Part 682...

  14. 40 CFR Appendixes A-C to Part 403 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  15. 40 CFR Appendixes A-C to Part 403 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 29 2011-07-01 2009-07-01 true A Appendixes A-C to Part 403 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PRE-TREAT-MENT REGULATIONS FOR EXIST-ING AND NEW SOURCES OF POLLUTION Appendixes A-C to Part 403...

  16. AC magnetohydrodynamic microfluidic switch

    SciTech Connect

    Lemoff, A V; Lee, A P

    2000-03-02

    A microfluidic switch has been demonstrated using an AC Magnetohydrodynamic (MHD) pumping mechanism in which the Lorentz force is used to pump an electrolytic solution. By integrating two AC MHD pumps into different arms of a Y-shaped fluidic circuit, flow can be switched between the two arms. This type of switch can be used to produce complex fluidic routing, which may have multiple applications in {micro}TAS.

  17. AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT XVIII, ALTERNATOR AND REGULATOR SERVICING AND TESTING, AND AN INTRODUCTION TO TRANSISTOR REGULATORS.

    ERIC Educational Resources Information Center

    Minnesota State Dept. of Education, St. Paul. Div. of Vocational and Technical Education.

    THIS MODULE OF A 25-MODULE COURSE IS DESIGNED AS A REVIEW OF THE OPERATING PRINCIPLES AND SERVICING PROCEDURES FOR GENERATORS AND AS AN INTRODUCTION TO TRANSISTOR CONTROLLED VOLTAGE REGULATION FOR GENERATORS USED ON DIESEL POWERED EQUIPMENT. TOPICS ARE (1) REVIEW OF GENERATOR PRINCIPLES, AC AND DC, (2) SERVICING AND TESTING ALTERNATORS, AND (3)…

  18. Regulation of pyruvate dehydrogenase activity and citric acid cycle intermediates during high cardiac power generation.

    PubMed

    Sharma, Naveen; Okere, Isidore C; Brunengraber, Daniel Z; McElfresh, Tracy A; King, Kristen L; Sterk, Joseph P; Huang, Hazel; Chandler, Margaret P; Stanley, William C

    2005-01-15

    A high rate of cardiac work increases citric acid cycle (CAC) turnover and flux through pyruvate dehydrogenase (PDH); however, the mechanisms for these effects are poorly understood. We tested the hypotheses that an increase in cardiac energy expenditure: (1) activates PDH and reduces the product/substrate ratios ([NADH]/[NAD(+)] and [acetyl-CoA]/[CoA-SH]); and (2) increases the content of CAC intermediates. Measurements were made in anaesthetized pigs under control conditions and during 15 min of a high cardiac workload induced by dobutamine (Dob). A third group was made hyperglycaemic (14 mm) to stimulate flux through PDH during the high work state (Dob + Glu). Glucose and fatty acid oxidation were measured with (14)C-glucose and (3)H-oleate. Compared with control, the high workload groups had a similar increase in myocardial oxygen consumption ( and cardiac power. Dob increased PDH activity and glucose oxidation above control, but did not reduce the [NADH]/[NAD(+)] and [acetyl-CoA]/[CoA-SH] ratios, and there were no differences between the Dob and Dob + Glu groups. An additional group was treated with Dob + Glu and oxfenicine (Oxf) to inhibit fatty acid oxidation: this increased [CoA-SH] and glucose oxidation compared with Dob; however, there was no further activation of PDH or decrease in the [NADH]/[NAD(+)] ratio. Content of the 4-carbon CAC intermediates succinate, fumarate and malate increased 3-fold with Dob, but there was no change in citrate content, and the Dob + Glu and Dob + Glu + Oxf groups were not different from Dob. In conclusion, compared with normal conditions, at high myocardial energy expenditure (1) the increase in flux through PDH is regulated by activation of the enzyme complex and continues to be partially controlled through inhibition by fatty acid oxidation, and (2) there is expansion of the CAC pool size at the level of 4-carbon intermediates that is largely independent of myocardial fatty acid oxidation.

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

    PubMed

    Segawa, Hiroyo; Okano, Hironaga; Wada, Kenji; Inoue, Satoru

    2014-02-01

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

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

    NASA Astrophysics Data System (ADS)

    Segawa, Hiroyo; Okano, Hironaga; Wada, Kenji; Inoue, Satoru

    2014-02-01

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

  1. The Effect of Hydroelectric Power Plants (hpp) on Agro-Life at Rural Land Regulation in Turkey

    NASA Astrophysics Data System (ADS)

    Onursal Denli, G.; Denli, H. H.; Seker, D. Z.; Bitik, E.; Cetin, S.

    2014-12-01

    Turkey is one of the self-sufficient in foodstuffs and globally ranks as 7th significant agricultural exporter in the world. Main trading partners are the European Union, the United States and the Middle East. As known, agricultural production is dependent on factors including efficient and effective use of all inputs ranging from those natural resources as in land and water to well-trained human resources as labour at the production. The socio-economic aspects of this sector take several forms ranging from the incomes of the primary producers. Rural land regulation is a necessity for rural areas and is regarded as a useful instrument for improving farmer's incomes and life standards. The irrigation system, established during the rural regulation/land consolidation period of large-scale farming, is insufficiently adjusted to the new land tenure structures. The government is especially in the process of water management with hydroelectric power plants. This process produces energy that is required but effects negatively the rivers and agricultural, environmental, climatic conditions. Rivers are vessels of the nature. Free flowing rivers give life to all nature. Most of the studies indicate that Hydroelectric Power Plants (HPP) affects the surface and ground-water management, natural life, agricultural productivity, socio-economic situation at agricultural regions and agro-life related with immigration. This study emphasizes the effect of Hydroelectric Power Plants which are used in transformation of water as a renewable natural resource into electricity power from the perspective of environmental policies and rural regulation.

  2. Basic concepts of induced AC voltages on pipelines

    SciTech Connect

    Kirkpatrick, E.L.

    1995-07-01

    The phenomena of induced AC on pipelines sharing common rights-of-way with overhead high-voltage electrical transmission power lines is discussed. Basic concepts and techniques for personnel safety and some pipeline protective measures are reviewed.

  3. Dc to ac converter operates efficiently at low input voltages

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Self-oscillating dc to ac converter with transistor switching to produce a square wave output is used for low and high voltage power sources. The converter has a high efficiency throughout a wide range of loads.

  4. Distribution-Agnostic Stochastic Optimal Power Flow for Distribution Grids

    SciTech Connect

    Baker, Kyri; Dall'Anese, Emiliano; Summers, Tyler

    2016-11-21

    This paper outlines a data-driven, distributionally robust approach to solve chance-constrained AC optimal power flow problems in distribution networks. Uncertain forecasts for loads and power generated by photovoltaic (PV) systems are considered, with the goal of minimizing PV curtailment while meeting power flow and voltage regulation constraints. A data- driven approach is utilized to develop a distributionally robust conservative convex approximation of the chance-constraints; particularly, the mean and covariance matrix of the forecast errors are updated online, and leveraged to enforce voltage regulation with predetermined probability via Chebyshev-based bounds. By combining an accurate linear approximation of the AC power flow equations with the distributionally robust chance constraint reformulation, the resulting optimization problem becomes convex and computationally tractable.

  5. An Set-Free, All Digital Controlled Point-of-Load Regulator for Next Generation Power Systems: ADC-POL

    NASA Technical Reports Server (NTRS)

    Adell, Philippe C.; Liu, Tao; Vermeire, Bert; Bakkaloglu, Bertan; Aveline, David

    2011-01-01

    This paper presents a digitally controlled programmable point-of-load regulator for next-generation power systems. A novel digital control scheme was designed to minimize single-event effect (SEE)-induced transient effects. By effectively programming the loop transmission, the POL can trade off transient response time with SET robustness. The IC works with 1 to 5.5 V input voltage, 1-4.5V regulated output voltage, high efficiency (peak efficiency at 94%) and power of up to 5 W. The design was fabricated in the AMI i2t100 0.7 mu m complimentary, metal-oxide semiconductor (CMOS) process and characterized with the Jet Propulsion Laboratory (JPL) pulsed laser system.

  6. Optimal design of AC filter circuits in HVDC converter stations

    SciTech Connect

    Saied, M.M.; Khader, S.A.

    1995-12-31

    This paper investigates the reactive power as well as the harmonic conditions on both the valve and the AC-network sides of a HVDC converter station. The effect of the AC filter circuits is accurately modeled. The program is then augmented by adding an optimization routine. It can identify the optimal filter configuration, yielding the minimum current distortion factor at the AC network terminals for a prespecified fundamental reactive power to be provided by the filter. Several parameter studies were also conducted to illustrate the effect of accidental or intentional deletion of one of the filter branches.

  7. [Polish regulations on maximum admissible intensities for electric and magnetic frequencies of 60 Hz and the European Union recommendations for electrical power engineering].

    PubMed

    Groszko, Marian

    2003-01-01

    Electric and magnetic fields of 50 Hz from electric power devices affect not only workers, but also the general population, as these devices are also located in populated areas, hence the duality of regulations on maximum admissible intensities. This paper presents these regulations and discusses in detail the changes of 2001. Based on the Polish regulations, hygienic evaluation of electric power devices has been attempted. The Polish regulations on the 50 Hz electromagnetic fields were compared with relevant international regulations of CENELEC and the European Union recommendations. Our maximum admissible intensities have been found to conform with the international standards.

  8. Power management and frequency regulation for microgrid and smart grid: A real-time demand response approach

    NASA Astrophysics Data System (ADS)

    Pourmousavi Kani, Seyyed Ali

    Future power systems (known as smart grid) will experience a high penetration level of variable distributed energy resources to bring abundant, affordable, clean, efficient, and reliable electric power to all consumers. However, it might suffer from the uncertain and variable nature of these generations in terms of reliability and especially providing required balancing reserves. In the current power system structure, balancing reserves (provided by spinning and non-spinning power generation units) usually are provided by conventional fossil-fueled power plants. However, such power plants are not the favorite option for the smart grid because of their low efficiency, high amount of emissions, and expensive capital investments on transmission and distribution facilities, to name a few. Providing regulation services in the presence of variable distributed energy resources would be even more difficult for islanded microgrids. The impact and effectiveness of demand response are still not clear at the distribution and transmission levels. In other words, there is no solid research reported in the literature on the evaluation of the impact of DR on power system dynamic performance. In order to address these issues, a real-time demand response approach along with real-time power management (specifically for microgrids) is proposed in this research. The real-time demand response solution is utilized at the transmission (through load-frequency control model) and distribution level (both in the islanded and grid-tied modes) to provide effective and fast regulation services for the stable operation of the power system. Then, multiple real-time power management algorithms for grid-tied and islanded microgrids are proposed to economically and effectively operate microgrids. Extensive dynamic modeling of generation, storage, and load as well as different controller design are considered and developed throughout this research to provide appropriate models and simulation

  9. "Power, Regulation and Physically Active Identities": The Experiences of Rural and Regional Living Adolescent Girls

    ERIC Educational Resources Information Center

    Casey, M.; Mooney, A.; Smyth, J.; Payne, W.

    2016-01-01

    Drawing on interpretations of Foucault's techniques of power, we explored the discourses and power relations operative between groups of girls that appeared to influence their participation in Physical Education (PE) and outside of school in sport and physical activity (PA) in rural and regional communities. Interviews and focus groups were…

  10. Three phase AC motor controller

    DOEpatents

    Vuckovich, Michael; Wright, Maynard K.; Burkett, John P.

    1984-03-20

    A motor controller for a three phase AC motor (10) which is adapted to operate bidirectionally from signals received either from a computer (30) or a manual control (32). The controller is comprised of digital logic circuit means which implement a forward and reverse command signal channel (27, 29) for the application of power through the forward and reverse power switching relays (16, 18, 20, 22). The digital logic elements are cross coupled to prevent activation of both channels simultaneously and each includes a plugging circuit (65, 67) for stopping the motor upon the removal of control signal applied to one of the two channels (27, 29) for a direction of rotation desired. Each plugging circuit (65, 67) includes a one-shot pulse signal generator (88, 102) which outputs a single pulse signal of predetermined pulsewidth which is adapted to inhibit further operation of the application of power in the channel which is being activated and to apply a reversal command signal to the other channel which provides a reversed phase application of power to the motor for a period defined by the pulse-width output of the one-shot signal generator to plug the motor (10) which will then be inoperative until another rotational command signal is applied to either of the two channels.

  11. ACS CCDs daily monitor

    NASA Astrophysics Data System (ADS)

    Sirianni, Marco

    2006-07-01

    This program consists of a set of basic tests to monitor, the read noise, thedevelopment of hot pixels and test for any source of noise in ACS CCDdetectors. The files, biases and dark will be used to create referencefiles for science calibration. This programme will be for the entire lifetime of ACS.For cycle 15 the program will cover 18 months 12.1.06->05.31.08and it has been divied into three different proposal each covering six months.The three poroposal are 11041-11042-11043.

  12. AC-DC Power Processor, Type I.

    DTIC Science & Technology

    1979-11-01

    LLI- >- Crto C) UU- LIJj LLJLJ Q 0d CC LJ CC LA exLLIW LL-13- c c. System Waveforms. Figure 6 shows the control system waveforms which includes the...C mJJ9 aJ mi oli o. o o a, aO ~ ~ ’ ’ 0 C. 1.0 r-.J a, 0) a, m- a, 00 00.0 0% (-> ) V - C - q r I 0D 0 0DC < cc 1.0 W 000 a LO~ r- LO Ul) U) Lo UO...o tt ; q ; t .. .. .. I -- ... ...... 0.. .. . . .. . . ~i31b~dI1Ik. ... ... LodA 3dV~~~~.. ....2 ..ZLI ~ ~O 63l t iJ w il. 4 N ... ... . . 4

  13. Process stabilization by peak current regulation in reactive high-power impulse magnetron sputtering of hafnium nitride

    NASA Astrophysics Data System (ADS)

    Shimizu, T.; Villamayor, M.; Lundin, D.; Helmersson, U.

    2016-02-01

    A simple and cost effective approach to stabilize the sputtering process in the transition zone during reactive high-power impulse magnetron sputtering (HiPIMS) is proposed. The method is based on real-time monitoring and control of the discharge current waveforms. To stabilize the process conditions at a given set point, a feedback control system was implemented that automatically regulates the pulse frequency, and thereby the average sputtering power, to maintain a constant maximum discharge current. In the present study, the variation of the pulse current waveforms over a wide range of reactive gas flows and pulse frequencies during a reactive HiPIMS process of Hf-N in an Ar-N2 atmosphere illustrates that the discharge current waveform is a an excellent indicator of the process conditions. Activating the reactive HiPIMS peak current regulation, stable process conditions were maintained when varying the N2 flow from 2.1 to 3.5 sccm by an automatic adjustment of the pulse frequency from 600 Hz to 1150 Hz and consequently an increase of the average power from 110 to 270 W. Hf-N films deposited using peak current regulation exhibited a stable stoichiometry, a nearly constant power-normalized deposition rate, and a polycrystalline cubic phase Hf-N with (1 1 1)-preferred orientation over the entire reactive gas flow range investigated. The physical reasons for the change in the current pulse waveform for different process conditions are discussed in some detail.

  14. AC/RF Superconductivity

    SciTech Connect

    Ciovati, Gianluigi

    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.

  15. 21 CFR 890.3710 - Powered communication system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... communication system. (a) Identification. A powered communication system is an AC- or battery-powered device... to use normal communication methods because of physical impairment. Examples of powered...

  16. Evaluation of modern IGBT-modules for hard-switched AC/DC/AC converters

    SciTech Connect

    Blaabjerg, F.; Pedersen, J.K.; Jaeger, U.

    1995-12-31

    The development of IGBT devices is still producing faster devices with lower losses. The applications become more advanced like a complete hard-switched AC/DC/AC converter with almost clean input current and regenerating capabilities. This paper will first focus on a detailed characterization and comparison of eight different IGBT-modules representing state-of-the-art for both PT and NPT technologies. The voltage level of the devices is 1,200V and 1,600V/1,700V. The characterization is done on an advanced measurement system which is briefly described. The characterization is based on static and dynamic tests for both IGBT and the diodes in the IGBT-modules at a junction temperature at 125 C. The comparison is first done directly based on conduction losses and switching losses, and later the measurements are used in a loss model for a complete AC/DC/AC converter application. In the AC/DC/AC converter the power losses are modelled, and different operating conditions are compared like different voltage levels in the DC-link. It is concluded dependent on operation conditions different devices will be preferable, but the high voltage devices have the highest losses even at a high operating voltage.

  17. Temperature effect on the chemomechanical regulation of substeps within the power stroke of a single Myosin II

    PubMed Central

    Dong, Chenling; Chen, Bin

    2016-01-01

    Myosin IIs in the skeletal muscle are highly efficient nanoscale machines evolved in nature. Understanding how they function can not only bring insights into various biological processes but also provide guidelines to engineer synthetic nanoscale motors working in the vicinity of thermal noise. Though it was clearly demonstrated that the behavior of a skeletal muscle fiber, or that of a single myosin was strongly affected by the temperature, how exactly the temperature affects the kinetics of a single myosin is not fully understood. By adapting the newly developed transitional state model, which successfully explained the intriguing motor force regulation during skeletal muscle contraction, here we systematically explain how exactly the power stroke of a single myosin proceeds, with the consideration of the chemomechanical regulation of sub-steps within the stroke. The adapted theory is then utilized to investigate the temperature effect on various aspects of the power stroke. Our analysis suggests that, though swing rates, the isometric force, and the maximal stroke size all strongly vary with the temperature, the temperature can have a very small effect on the releasable elastic energy within the power stroke. PMID:26786569

  18. Power

    SciTech Connect

    1999-10-01

    Subjects covered in this section are: (1) CP and L, Florida Progress to create new company through merger; (2) Violations are color-coded under new NRC enforcement policy; (3) NRC confirms that nuclear plants are Y2K ready; (4) NIRS denied NRC ruling; (5) NRC to allow lower insurance coverage on shutdown TMI-2; (6) NRC look to change noncombustibility regulation; and (7) Electronic NRC reading room scheduled to open.

  19. Prognostic health monitoring in switch-mode power supplies with voltage regulation

    NASA Technical Reports Server (NTRS)

    Hofmeister, James P (Inventor); Judkins, Justin B (Inventor)

    2009-01-01

    The system includes a current injection device in electrical communication with the switch mode power supply. The current injection device is positioned to alter the initial, non-zero load current when activated. A prognostic control is in communication with the current injection device, controlling activation of the current injection device. A frequency detector is positioned to receive an output signal from the switch mode power supply and is able to count cycles in a sinusoidal wave within the output signal. An output device is in communication with the frequency detector. The output device outputs a result of the counted cycles, which are indicative of damage to an a remaining useful life of the switch mode power supply.

  20. Technical Aspects of the Advanced Camera For Surveys Repair (ACS-R)

    NASA Technical Reports Server (NTRS)

    Rinehart, Stephen; Cheng, Edward S.; Sirianni, Marco

    2008-01-01

    The ACS Repair (ACS-R) team includes contributors from NASA's Goddard Space Flight Center, Ball Aerospace, and Teledyne Imaging Sensors; It determined that all of the capabilities of the ACS could be restored and created a concept for the ACS-R component of SN4. ACSR will restore the WFC of ACS by replacing the existing CCD Electronics Box (CEB) with the CEB-Replacement (CEB-R) and providing power from a new Low Voltage Power Supply Replacement (LVPS-8). The new LVPS-R will also attempt to restore the HRC function by providing power through the original power bus. In this presentation, we faeus on the concept and technical aspects of the ACS-R.

  1. Regulating glottal airflow in phonation: Application of the maximum power transfer theorem to a low dimensional phonation model

    NASA Astrophysics Data System (ADS)

    Titze, Ingo R.

    2002-01-01

    Two competing views of regulating glottal airflow for maximum vocal output are investigated theoretically. The maximum power transfer theorem is used as a guide. A wide epilarynx tube (laryngeal vestibule) matches well with low glottal resistance (believed to correspond to the ``yawn-sigh'' approach in voice therapy), whereas a narrow epilarynx tube matches well with a higher glottal resistance (believed to correspond to the ``twang-belt'' approach). A simulation model is used to calculate mean flows, peak flows, and oral radiated pressure for an impedance ratio between the vocal tract (the load) and the glottis (the source). Results show that when the impedance ratio approaches 1.0, maximum power is transferred and radiated from the mouth. A full update of the equations used for simulating driving pressures, glottal flow, and vocal tract input pressures is provided as a programming guide for those interested in model development.

  2. Preliminary Performance Data on Westinghouse Electronic Power Regulator Operating on J34-WE-32 Turbojet Engine in Altitude Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Ketchum, James R.; Blivas, Darnold; Pack, George J.

    1950-01-01

    The behavior of the Westinghouse electronic power regulator operating on a J34-WE-32 turbojet engine was investigated in the NACA Lewis altitude wind tunnel at the request of the Bureau of Aeronautics, Department of the Navy. The object of the program was to determine the, steady-state stability and transient characteristics of the engine under control at various altitudes and ram pressure ratios, without afterburning. Recordings of the response of the following parameters to step changes in power lever position throughout the available operating range of the engine were obtained; ram pressure ratio, compressor-discharge pressure, exhaust-nozzle area, engine speed, turbine-outlet temperature, fuel-valve position, jet thrust, air flow, turbine-discharge pressure, fuel flow, throttle position, and boost-pump pressure. Representative preliminary data showing the actual time response of these variables are presented. These data are presented in the form of reproductions of oscillographic traces.

  3. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... transmitters. Section 73.658—Affiliation agreements and network program practices; territorial exclusivity in non-network program arrangements. Part 73, Subpart G—Emergency Broadcast System (for low power TV.... Section 73.1692—Construction near or installations on an AM broadcast tower. Section 73.1940—Broadcasts...

  4. Congress, the FCC and Children's Television Regulation: A Shift in the Balance of Power.

    ERIC Educational Resources Information Center

    Markin, Karen

    The Federal Communications Commission (FCC) of the late 1980s appeared to pursue its own agenda of broadcast deregulation, notwithstanding congressional pressures. The apparent power shift is evident in a case study of the interactions between Congress and the FCC on the subject of children's television. In the early 1970s, the FCC tended to…

  5. Single-cell epigenomics: powerful new methods for understanding gene regulation and cell identity.

    PubMed

    Clark, Stephen J; Lee, Heather J; Smallwood, Sébastien A; Kelsey, Gavin; Reik, Wolf

    2016-04-18

    Emerging single-cell epigenomic methods are being developed with the exciting potential to transform our knowledge of gene regulation. Here we review available techniques and future possibilities, arguing that the full potential of single-cell epigenetic studies will be realized through parallel profiling of genomic, transcriptional, and epigenetic information.

  6. The Power of Social and Motivational Relationships for Test-Anxious Adolescents' Academic Self-Regulation

    ERIC Educational Resources Information Center

    Raufelder, Diana; Hoferichter, Frances; Schneeweiss, David; Wood, Megan A.

    2015-01-01

    Based on cognitive evaluation theory (CET) and organismic integration theory (OIT)--both sub-theories of self-determination theory (SDT)--the present study examined whether the academic self-regulation of youth with test anxiety can be strengthened through social and motivational relationships with peers and teachers. This study employed a large…

  7. Teaching Glycosis Regulation to Undergraduates Using An Electrical Power Generation Analogy

    ERIC Educational Resources Information Center

    Stavrianeas, Stasinos

    2005-01-01

    Biology, physiology, and allied health biochemistry textbooks cover metabolic pathways such as glycolysis; however, most do not include much discussion of how these pathways are regulated within the cell. Because the details of these complex regulatory processes can be difficult for students to learn, we have developed a robust teaching…

  8. Photovoltaic power generation for air-conditioning system based on predictive control

    SciTech Connect

    Kim, S.; Choi, J.; Park, G.; Yoo Jiyoon

    1995-12-31

    In this paper an auxiliary power supply scheme using photovoltaic power generation for air-conditioning system and its novel control strategy are proposed. The proposed auxiliary power supply system employs a boost converter, a bidirectional power converter and photovoltaic arrays. The boost converter controlled by a predictive control strategy provides maximum power track (MPT) state on the photovoltaic (PV) arrays as well as power generation facility function on the ac utility grid. Furthermore the bidirectional power converter controls the power flow balance between the loads and two different power sources according to the condition of the load power and the supplied power from photovoltaic arrays. It is shown that the maximum power tracking of the PV arrays, the unit power factor of ac utility grid and the descent input dc voltage regulation of the air-conditioning system are achieved by the proposed predictive control strategy. The proposed switching strategy for the boost converter and the bidirectional power converter are based on the predictive control with ac line current and output voltage of the PV arrays. The bidirectional power converter is suitably modulation controlled to rectify the ac source during the power shortage under the poor power generation of PV arrays or over load conditions of air conditioner. During the opposite state, the bidirectional power converter is gated to function as a regeneration inverter. Controller design procedure for the proposed approach to achieve near sinusoidal input currents under the inverter mode and the rectifier mode is detailed. Simulation results on a laboratory prototype system are discussed. Experimental results from the laboratory prototype system will be presented in the near future.

  9. Cascading failures in ac electricity grids.

    PubMed

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

    2016-09-01

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

  10. Cascading failures in ac electricity grids

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  11. Combinatorial effects of genistein and sex-steroids on the level of cystic fibrosis transmembrane regulator (CFTR), adenylate cyclase (AC) and cAMP in the cervix of ovariectomised rats.

    PubMed

    Salleh, Naguib; Ismail, Nurain; Muniandy, Sekaran; Korla, Praveen Kumar; Giribabu, Nelli

    2015-12-01

    The combinatorial effects of genistein and estrogen (E) or estrogen plus progesterone (E+P) on CFTR, AC and cAMP levels in cervix were investigated. Ovariectomised adult female rats received 50 or 100mg/kg/day genistein with E or E followed by E+P [E+(E+P)] for seven consecutive days. Cervixes were harvested and analyzed for CFTR mRNA levels by Real-time PCR. Distribution of AC and CFTR proteins in endocervix were observed by immunohistochemistry. Levels of cAMP were measured by enzyme-immunoassay. Molecular docking predicted interaction between genistein and AC. Our results indicate that levels of CFTR, AC and cAMP in cervix of rats receiving genistein plus E were higher than E-only treatment (p<0.05) while genistein plus [E+(E+P)] were higher than E+(E+P)-only treatment (p<0.05). In conclusions, increased levels of CFTR, AC and cAMP in cervix of E and E+(E+P)-treated rats by genistein could affect the cervical secretory function which could influence the female reproductive processes.

  12. A Computer Model for Teaching the Dynamic Behavior of AC Contactors

    ERIC Educational Resources Information Center

    Ruiz, J.-R. R.; Espinosa, A. G.; Romeral, L.

    2010-01-01

    Ac-powered contactors are extensively used in industry in applications such as automatic electrical devices, motor starters, and heaters. In this work, a practical session that allows students to model and simulate the dynamic behavior of ac-powered electromechanical contactors is presented. Simulation is carried out using a rigorous parametric…

  13. Change-in-law provisions in a carbon-constrained America: the impact of carbon regulation on long-term power purchase agreements

    SciTech Connect

    Harms, Brian C.

    2009-06-15

    Policymakers now are acting on climate change initiatives. As new regulations are discussed, adopted, and applied to power plants, sellers and buyers of power will have to negotiate the appropriate risk allocation, both in terms of price and passthrough of costs. (author)

  14. A study of Schwarz converters for nuclear powered spacecraft

    NASA Technical Reports Server (NTRS)

    Stuart, Thomas A.; Schwarze, Gene E.

    1987-01-01

    High power space systems which use low dc voltage, high current sources such as thermoelectric generators, will most likely require high voltage conversion for transmission purposes. This study considers the use of the Schwarz resonant converter for use as the basic building block to accomplish this low-to-high voltage conversion for either a dc or an ac spacecraft bus. The Schwarz converter has the important assets of both inherent fault tolerance and resonant operation; parallel operation in modular form is possible. A regulated dc spacecraft bus requires only a single stage converter while a constant frequency ac bus requires a cascaded Schwarz converter configuration. If the power system requires constant output power from the dc generator, then a second converter is required to route unneeded power to a ballast load.

  15. A dry-cooled AC quantum voltmeter

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

  16. Simple circuit monitors "third wire" in ac lines

    NASA Technical Reports Server (NTRS)

    Kojima, T. T.; Stuck, D. E.

    1980-01-01

    Device detects interruption of ground connection in three-wire electrical equipment and shuts off ac power to prevent shock hazard. Silicon-controlled rectifiers detect floating ground, and deenergize optoelectric relays thereby breaking power connections. Circuit could be incorporated into hand tools, appliances, and other electrical equipment.

  17. High power valve regulated lead-acid batteries for new vehicle requirements

    NASA Astrophysics Data System (ADS)

    Trinidad, Francisco; Sáez, Francisco; Valenciano, Jesús

    The performance of high power VRLA ORBITAL™ batteries is presented. These batteries have been designed with isolated cylindrical cells, providing high reliability to the recombination process, while maintaining, at the same time, a very high compression (>80 kPa) over the life of the battery. Hence, the resulting VRLA modules combine a high rate capability with a very good cycle performance. Two different electrochemically active material compositions have been developed: high porosity and low porosity for starting and deep cycle applications, respectively (depending on the power demand and depth of discharge). Although, the initial performance of the starting version is higher, after a few cycles the active material of the deep cycle version is fully developed, and this achieves the same high rate capability. Both types are capable of supplying the necessary reliability for cranking at the lowest temperature (-40°C). Specific power of over 500 W/kg is achievable at a much lower cost than for nickel-metal hydride systems. Apart from the initial performance, an impressive behaviour of the cycling version has been found in deep cycle applications, due to the highly compressed and high density active material. When submitted to continuous discharge-charge cycles at 75% (IEC 896-2 specification) and 100% (BCI deep cycle) DoD, it has been found that the batteries are still healthy after more than 1000 and 700 cycles, respectively. However, it has been proven that the application of an IUi algorithm (up to 110% of overcharging) with a small constant current charging period at the end of the charge is absolutely necessary to achieve the above results. Without the final boosting period, the cycle life of the battery could be substantially shortened. The high specific power and reliability observed in the tests carried out, would allow ORBITAL™ batteries to comply with the more demanding requirements that are being introduced in conventional and future hybrid electric

  18. A feed-forward controlled AC-DC boost converter for biomedical implants.

    PubMed

    Jiang, Hao; Lan, Di; Lin, Dahsien; Zhang, Junmin; Liou, Shyshenq; Shahnasser, Hamid; Shen, Ming; Harrison, Michael; Roy, Shuvo

    2012-01-01

    Miniaturization is important to make implants clinic friendly. Wireless power transfer is an essential technology to miniaturize implants by reducing their battery size or completely eliminating their batteries. Traditionally, a pair of inductively-coupled coils operating at radio-frequency (RF) is employed to deliver electrical power wirelessly. In this approach, a rectifier is needed to convert the received RF power to a stable DC one. To achieve high efficiency, the induced voltage of the receiving coil must be much higher than the turn-on voltage of the rectifying diode (which could be an active circuit for low turn-on voltage) [1]. In order to have a high induced voltage, the size of the receiving coil often is significantly larger than rest of the implant. A rotating magnets based wireless power transfer has been demonstrated to deliver the same amount of power at much lower frequency (around 100 Hz) because of the superior magnetic strength produced by rare-earth magnets [2]. Taking the advantage of the low operating frequency, an innovative feed-forward controlled AC to DC boost converter has been demonstrated for the first time to accomplish the following two tasks simultaneously: (1) rectifying the AC power whose amplitude (500 mV) is less than the rectifier's turn-on voltage (1.44 V) and (2) boosting the DC output voltage to a much higher level (5 V). Within a range, the output DC voltage can be selected by the control circuit. The standard deviation of the output DC voltage is less than 2.1% of its mean. The measured load regulation is 0.4 V/kΩ. The estimated conversion efficiency excluding the power consumption of the control circuits reaches 75%. The converter in this paper has the potential to reduce the size of the receiving coil and yet achieve desirable DC output voltage for powering biomedical implants.

  19. Applicability of the PSD Regulations to Powerplants that are Certified by DOE as Peakload Power Plants

    EPA Pesticide Factsheets

    This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

  20. Body-building without power training: endogenously regulated pectoral muscle hypertrophy in confined shorebirds

    PubMed

    Dietz; Piersma; Dekinga

    1999-10-01

    Shorebirds such as red knots Calidris canutus routinely make migratory flights of 3000 km or more. Previous studies on this species, based on compositional analyses, suggest extensive pectoral muscle hypertrophy in addition to fat storage before take-off. Such hypertrophy could be due to power training and/or be effected by an endogenous circannual rhythm. Red knots of two subspecies with contrasting migration patterns were placed in a climate-controlled aviary (12 h:12 h L:D photoperiod) where exercise was limited. Using ultrasonography, we measured pectoral muscle size as the birds stored fat in preparation for migration. At capture, there were no differences in body mass and pectoral muscle mass between the two subspecies. As they prepared for southward and northward migration, respectively, the tropically wintering subspecies (C. c. canutus) gained 31 g and the temperate wintering subspecies (C. c. islandica) gained 41 g. During this time, pectoral mass increased by 43-44 % of initial mass, representing 39 % (C. c. canutus) and 29 % (C. c. islandica) of the increase in body mass. The gizzard showed atrophy in conjunction with a diet change from molluscs to food pellets. Although we cannot exclude the possibility that the birds' limited movement may still be a prerequisite for pectoral muscle hypertrophy, extensive power training is certainly not a requirement. Muscle hypertrophy in the absence of photoperiod cues suggests the involvement of an endogenous circannual process.

  1. TRAF3 as a powerful and multitalented regulator of lymphocyte functions.

    PubMed

    Bishop, Gail A

    2016-11-01

    This review summarizes the current state of knowledge regarding the roles of the signaling adapter protein tumor necrosis factor receptor (TNFR)-associated factor 3 in regulating the functions of B and T lymphocytes. In B lymphocytes, TNFR-associated factor 3 inhibits signaling by TNFR superfamily receptors, Toll-like receptors, and interleukin-6R. In contrast, signaling to B cells by the virally encoded oncogenic protein latent membrane protein 1 is promoted by TNFR-associated factor 3. An important B cell-specific role for TNFR-associated factor 3 is the inhibition of homeostatic survival, directly relevant to the common occurrence of TNFR-associated factor 3 mutations in human B cell malignancies. TNFR-associated factor 3 was recently found to be a resident nuclear protein in B cells, where it interacts with and inhibits gene expression mediated by the cAMP response element-binding protein transcription complex, including expression of the prosurvival protein myeloid leukemia cell differentiation protein 1. In T lymphocytes, TNFR-associated factor 3 is required for normal signaling by the T cell antigen receptor, while inhibiting signaling by the interleukin-2 receptor. Cytoplasmic TNFR -associated factor 3 restrains nuclear factor-κB2 activation in both T and B cells. Clinical implications and future directions for the study of this context-dependent signaling regulator are discussed.

  2. A powerful hybrid puc operon promoter tightly regulated by both IPTG and low oxygen level.

    PubMed

    Hu, Zongli; Zhao, Zhiping; Pan, Yu; Tu, Yun; Chen, Guoping

    2010-04-01

    Rhodobacter sphaeroides has been intensively studied and provides an excellent model for studying both photosynthesis and membrane development. The photosynthetic apparatus (LH2 and LH1-RC complexes) can be synthesized in large scale and integrated into the intracytoplasmic membrane system under specific conditions, which thus provides us insight to utilize the puc or(and) puf operon to heterologously express recombinant proteins in the intracytoplasmic membrane using Rb. sphaeroides as a novel expression system. However, basal level of expression of puc and puf promoter is uncontrolled. We report the construction of LH2 polypeptide expression vector that contains a reengineered lacI(q)-puc promoter-lac operator hybrid promoter, which allows the puc operon to be regulated by both IPTG and low oxygen level. Synthesis of LH2 complexes was completely repressed in the absence of isopropyl beta-D-thiogalactoside (IPTG), and the degree of induction was controlled by varying the concentration of IPTG. The optimal concentration of IPTG was determined. SDS-PAGE and Western blot were employed for further analysis. Our results suggest that the reengineered hybrid promoter is efficient to tightly regulate the expression of the puc operon, and our strategy can open up a new approach in the study of the membrane protein expression system.

  3. Power superconducting power transmission cable

    DOEpatents

    Ashworth, Stephen P.

    2003-06-10

    The present invention is for a compact superconducting power transmission cable operating at distribution level voltages. The superconducting cable is a conductor with a number of tapes assembled into a subconductor. These conductors are then mounted co-planarly in an elongated dielectric to produce a 3-phase cable. The arrangement increases the magnetic field parallel to the tapes thereby reducing ac losses.

  4. Power superconducting power transmission cable

    DOEpatents

    Ashworth, Stephen P.

    2003-01-01

    The present invention is for a compact superconducting power transmission cable operating at distribution level voltages. The superconducting cable is a conductor with a number of tapes assembled into a subconductor. These conductors are then mounted co-planarly in an elongated dielectric to produce a 3-phase cable. The arrangement increases the magnetic field parallel to the tapes thereby reducing ac losses.

  5. Distributed Hierarchical Control of Multi-Area Power Systems with Improved Primary Frequency Regulation

    SciTech Connect

    Lian, Jianming; Marinovici, Laurentiu D.; Kalsi, Karanjit; Du, Pengwei; Elizondo, Marcelo A.

    2012-12-12

    The conventional distributed hierarchical control architecture for multi-area power systems is revisited. In this paper, a new distributed hierarchical control architecture is proposed. In the proposed architecture, pilot generators are selected in each area to be equipped with decentralized robust control as a supplementary to the conventional droop speed control. With the improved primary frequency control, the system frequency can be restored to the nominal value without the help of secondary frequency control, which reduces the burden of the automatic generation control for frequency restoration. Moreover, the low frequency inter-area electromechanical oscillations can also be effectively damped. The effectiveness of the proposed distributed hierarchical control architecture is validated through detailed simulations.

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

    NASA Astrophysics Data System (ADS)

    Khoshkbar Sadigh, Arash

    Part I: Dynamic Voltage Restorer In the present power grids, voltage sags are recognized as a serious threat and a frequently occurring power-quality problem and have costly consequence such as sensitive loads tripping and production loss. Consequently, the demand for high power quality and voltage stability becomes a pressing issue. Dynamic voltage restorer (DVR), as a custom power device, is more effective and direct solutions for "restoring" the quality of voltage at its load-side terminals when the quality of voltage at its source-side terminals is disturbed. In the first part of this thesis, a DVR configuration with no need of bulky dc link capacitor or energy storage is proposed. This fact causes to reduce the size of the DVR and increase the reliability of the circuit. In addition, the proposed DVR topology is based on high-frequency isolation transformer resulting in the size reduction of transformer. The proposed DVR circuit, which is suitable for both low- and medium-voltage applications, is based on dc-ac converters connected in series to split the main dc link between the inputs of dc-ac converters. This feature makes it possible to use modular dc-ac converters and utilize low-voltage components in these converters whenever it is required to use DVR in medium-voltage application. The proposed configuration is tested under different conditions of load power factor and grid voltage harmonic. It has been shown that proposed DVR can compensate the voltage sag effectively and protect the sensitive loads. Following the proposition of the DVR topology, a fundamental voltage amplitude detection method which is applicable in both single/three-phase systems for DVR applications is proposed. The advantages of proposed method include application in distorted power grid with no need of any low-pass filter, precise and reliable detection, simple computation and implementation without using a phased locked loop and lookup table. The proposed method has been verified

  7. The A to Z of A/C plasmids.

    PubMed

    Harmer, Christopher J; Hall, Ruth M

    2015-07-01

    Plasmids belonging to incompatibility groups A and C (now A/C) were among the earliest to be associated with antibiotic resistance in Gram-negative bacteria. A/C plasmids are large, conjugative plasmids with a broad host range. The prevalence of A/C plasmids in collections of clinical isolates has revealed their importance in the dissemination of extended-spectrum β-lactamases and carbapenemases. They also mobilize SGI1-type resistance islands. Revived interest in the family has yielded many complete A/C plasmid sequences, revealing that RA1, designated A/C1, is different from the remainder, designated A/C2. There are two distinct A/C2 lineages. Backbones of 128-130 kb include over 120 genes or ORFs encoding proteins of at least 100 amino acids, but very few have been characterized. Genes potentially required for replication, stability and transfer have been identified, but only the replication system of RA1 and the regulation of transfer have been studied. There is enormous variety in the antibiotic resistance genes carried by A/C2 plasmids but they are usually clustered in larger regions at various locations in the backbone. The ARI-A and ARI-B resistance islands are always at a specific location but have variable content. ARI-A is only found in type 1 A/C2 plasmids, which disseminate blaCMY-2 and blaNDM-1 genes, whereas ARI-B, carrying the sul2 gene, is found in both type 1 and type 2. This review summarizes current knowledge of A/C plasmids, and highlights areas of research to be considered in the future.

  8. Distribution-Agnostic Stochastic Optimal Power Flow for Distribution Grids: Preprint

    SciTech Connect

    Baker, Kyri; Dall'Anese, Emiliano; Summers, Tyler

    2016-09-01

    This paper outlines a data-driven, distributionally robust approach to solve chance-constrained AC optimal power flow problems in distribution networks. Uncertain forecasts for loads and power generated by photovoltaic (PV) systems are considered, with the goal of minimizing PV curtailment while meeting power flow and voltage regulation constraints. A data- driven approach is utilized to develop a distributionally robust conservative convex approximation of the chance-constraints; particularly, the mean and covariance matrix of the forecast errors are updated online, and leveraged to enforce voltage regulation with predetermined probability via Chebyshev-based bounds. By combining an accurate linear approximation of the AC power flow equations with the distributionally robust chance constraint reformulation, the resulting optimization problem becomes convex and computationally tractable.

  9. AC resistance measuring instrument

    DOEpatents

    Hof, P.J.

    1983-10-04

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument. 8 figs.

  10. AC Resistance measuring instrument

    DOEpatents

    Hof, Peter J.

    1983-01-01

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument.

  11. Identification of /sup 233/Ac

    SciTech Connect

    Chu, Y.Y.; Zhou, M.L.

    1983-09-01

    We report in this paper identification of the new isotope /sup 233/Ac. Uranium targets were irradiated with 28 GeV protons; after rapid retrieval of the target and separation of actinium from thorium, /sup 233/Ac was allowed to decay into the known /sup 233/Th daughter. Exhaustive chemical purification was employed to permit the identification of /sup 233/Th via its characteristic ..gamma.. radiations. The half-life derived for /sup 233/Ac from several experiments is 2.3 +- 0.3 min. The production cross section for /sup 233/Ac is 100 ..mu..b.

  12. Emerging molecular mechanisms that power and regulate the anastral mitotic spindle of flowering plants.

    PubMed

    Bannigan, Alex; Lizotte-Waniewski, Michelle; Riley, Margaret; Baskin, Tobias I

    2008-01-01

    Flowering plants, lacking centrosomes as well as dynein, assemble their mitotic spindle via a pathway that is distinct visually and molecularly from that of animals and yeast. The molecular components underlying mitotic spindle assembly and function in plants are beginning to be discovered. Here, we review recent evidence suggesting the preprophase band in plants functions analogously to the centrosome in animals in establishing spindle bipolarity, and we review recent progress characterizing the roles of specific motor proteins in plant mitosis. Loss of function of certain minus-end-directed KIN-14 motor proteins causes a broadening of the spindle pole; whereas, loss of function of a KIN-5 causes the formation of monopolar spindles, resembling those formed when the homologous motor protein (e.g., Eg5) is knocked out in animal cells. We present a phylogeny of the kinesin-5 motor domain, which shows deep divergence among plant sequences, highlighting possibilities for specialization. Finally, we review information concerning the roles of selected structural proteins at mitosis as well as recent findings concerning regulation of M-phase in plants. Insight into the mitotic spindle will be obtained through continued comparison of mitotic mechanisms in a diversity of cells.

  13. Performance of Power Converters at Cryogenic Temperatures

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.

    2001-01-01

    Power converters capable of operation at cryogenic temperatures are anticipated to play an important role in the power system architecture of future NASA deep space missions. Design of such converters to survive cryogenic temperatures will improve the power system performance and reduce development and launch costs. Aerospace power systems are mainly a DC distribution network. Therefore, DC/DC and DC/AC converters provide the outputs needed to different loads at various power levels. Recently, research efforts have been performed at the NASA Glenn Research Center (GRC) to design and evaluate DC/DC converters that are capable of operating at cryogenic temperatures. This paper presents a summary of the research performed to evaluate the low temperature performance of five DC/DC converters. Various parameters were investigated as a function of temperature in the range of 20 to -196 C. Data pertaining to the output voltage regulation and efficiency of the converters is presented and discussed.

  14. Power training and postmenopausal hormone therapy affect transcriptional control of specific co-regulated gene clusters in skeletal muscle

    PubMed Central

    Fey, Vidal; Törmäkangas, Timo; Ronkainen, Paula H. A.; Taaffe, Dennis R.; Takala, Timo; Koskinen, Satu; Cheng, Sulin; Puolakka, Jukka; Kujala, Urho M.; Suominen, Harri; Sipilä, Sarianna; Kovanen, Vuokko

    2010-01-01

    At the moment, there is no clear molecular explanation for the steeper decline in muscle performance after menopause or the mechanisms of counteractive treatments. The goal of this genome-wide study was to identify the genes and gene clusters through which power training (PT) comprising jumping activities or estrogen containing hormone replacement therapy (HRT) may affect skeletal muscle properties after menopause. We used musculus vastus lateralis samples from early stage postmenopausal (50–57 years old) women participating in a yearlong randomized double-blind placebo-controlled trial with PT and HRT interventions. Using microarray platform with over 24,000 probes, we identified 665 differentially expressed genes. The hierarchical clustering method was used to assort the genes. Additionally, enrichment analysis of gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways was carried out to clarify whether assorted gene clusters are enriched with particular functional categories. The analysis revealed transcriptional regulation of 49 GO/KEGG categories. PT upregulated transcription in “response to contraction”—category revealing novel candidate genes for contraction-related regulation of muscle function while HRT upregulated gene expression related to functionality of mitochondria. Moreover, several functional categories tightly related to muscle energy metabolism, development, and function were affected regardless of the treatment. Our results emphasize that during the early stages of the postmenopause, muscle properties are under transcriptional modulation, which both PT and HRT partially counteract leading to preservation of muscle power and potentially reducing the risk for aging-related muscle weakness. More specifically, PT and HRT may function through improving energy metabolism, response to contraction as well as by preserving functionality of the mitochondria. Electronic supplementary material The online version of this

  15. A type III ACC synthase, ACS7, is involved in root gravitropism in Arabidopsis thaliana.

    PubMed

    Huang, Shih-Jhe; Chang, Chia-Lun; Wang, Po-Hsun; Tsai, Min-Chieh; Hsu, Pang-Hung; Chang, Ing-Feng

    2013-11-01

    Ethylene is an important plant hormone that regulates developmental processes in plants. The ethylene biosynthesis pathway is a highly regulated process at both the transcriptional and post-translational level. The transcriptional regulation of these ethylene biosynthesis genes is well known. However, post-translational modifications of the key ethylene biosynthesis enzyme 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) are little understood. In vitro kinase assays were conducted on the type III ACS, AtACS7, fusion protein and peptides to determine whether the AtACS7 protein can be phosphorylated by calcium-dependent protein kinase (CDPK). AtACS7 was phosphorylated at Ser216, Thr296, and Ser299 by AtCDPK16 in vitro. To investigate further the function of the ACS7 gene in Arabidopsis, an acs7-1 loss-of-function mutant was isolated. The acs7-1 mutant exhibited less sensitivity to the inhibition of root gravitropism by treatment with the calcium chelator ethylene glycol tetraacetic acid (EGTA). Seedlings were treated with gradient concentrations of ACC. The results showed that a certain concentration of ethylene enhanced the gravity response. Moreover, the acs7-1 mutant was less sensitive to inhibition of the gravity response by treatment with the auxin polar transport inhibitor 1-naphthylphthalamic acid, but exogenous ACC application recovered root gravitropism. Altogether, the results indicate that AtACS7 is involved in root gravitropism in a calcium-dependent manner in Arabidopsis.

  16. Design and Test of a Continuous Duty Pulsed AC Generator

    DTIC Science & Technology

    1991-06-01

    DESIGN AND TEST OF A CONTINUOUS DUTY PULSED AC GENERATOR* R. M. Calfo, D. J . Scott , and D. W. Scherbarth Westinghouse Electric Corporation...Proceedings of the 19th Power Modulator Symposium, June 26-28, 1990, San Diego, CA. Dennis J . Scott and Raymond M. Calfo, •Synchronous Machines for...Pulsed Power Applications,• Seventh IEEE Pulsed Power Conference, June 11-14, 1989, Monterey, CA. D. J . Scott , R. M. Calfo, H. R. Schwenk

  17. Cooling Floor AC Systems

    NASA Astrophysics Data System (ADS)

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

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

  18. Evolution of AC conductivity of wet illitic clay during drying

    NASA Astrophysics Data System (ADS)

    Csáki, Š.; Štubňa, I.; Trnovcová, V.; Ondruška, J.; Vozár, L.; Dobroň, P.

    2017-02-01

    The evolution of the AC electrical conductivity during drying as well as the relationship between sample volume and moisture of green illite samples were investigated. The samples were prepared from illitic clay (80 mass % illite, 4 mass % montmorillonite, 12 mass % quartz and 4 mass % of orthoclase) and distilled water with initial moisture content 36 mass % and were freely dried in air. Conductivity was measured by the volt-ampere method with AC power supply of 5 V in the frequency range from 50 Hz to 10 kHz. The AC conductivity steeply increased with increasing moisture, up to 15 mass %. At higher values of the moisture, the AC conductivity was high and almost constant. The volume of samples increased with increasing moisture when the moisture was higher than 8 mass %. Below this value, the dimensions of samples do not significantly change. The dependence of the relative volume change on moisture is presented in a form of the Bigot’s curve.

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

    PubMed Central

    Segawa, Hiroyo; Okano, Hironaga; Wada, Kenji; Inoue, Satoru

    2014-01-01

    Anodization techniques by alternating current (ac) are introduced in this review. By using ac anodization, laminated alumina films are fabricated. Different types of alumina films consisting of 50–200 nm layers were obtained by varying both the ac power supply and the electrolyte. The total film thickness increased with an increase in the total charge transferred. The thickness of the individual layers increased with the ac voltage; however, the anodization time had little effect on the film thickness. The laminated alumina films resembled the nacre structure of shells, and the different morphologies exhibited by bivalves and spiral shells could be replicated by controlling the rate of increase of the applied potentials. PMID:27877636

  20. Automated ac galvanomagnetic measurement system

    NASA Technical Reports Server (NTRS)

    Szofran, F. R.; Espy, P. N.

    1985-01-01

    An automated, ac galvanomagnetic measurement system is described. Hall or van der Pauw measurements in the temperature range 10-300 K can be made at a preselected magnetic field without operator attendance. Procedures to validate sample installation and correct operation of other system functions, such as magnetic field and thermometry, are included. Advantages of ac measurements are discussed.

  1. Power quality load management for large spacecraft electrical power systems

    NASA Technical Reports Server (NTRS)

    Lollar, Louis F.

    1988-01-01

    In December, 1986, a Center Director's Discretionary Fund (CDDF) proposal was granted to study power system control techniques in large space electrical power systems. Presented are the accomplishments in the area of power system control by power quality load management. In addition, information concerning the distortion problems in a 20 kHz ac power system is presented.

  2. Interconnection of a photovoltaic power generation system with the grid

    NASA Astrophysics Data System (ADS)

    Corbefin, R.; Vacelet, G.

    Converting photovoltaic system-generated power into a form compatible with grid-furnished power and simultaneously ensuring that maximal power is drawn from the solar system is discussed. A converter is interposed between the solar-derived electricity and the grid lines, allowing the user to apply the power to a load, feed excess power to the grid, and receive power from the grid when the photovoltaic output is too low to fill demand. A dc-ac converter is described, with microprocessor controlled transistorized switching to adapt the solar output to the load amplitude on demand, while maintaining constant voltage. An adaptor allows the converter to take its amplitude, phase, and frequency regulation from the grid, and also assures that power will flow only toward the grid.

  3. A low power on-chip class-E power amplifier for remotely powered implantable sensor systems

    NASA Astrophysics Data System (ADS)

    Ture, Kerim; Kilinc, Enver G.; Dehollain, Catherine

    2015-06-01

    This paper presents a low power fully integrated class-E power amplifier and its integration with remotely powered sensor system. The class-E power amplifier is suitable solution for low-power applications due to its high power efficiency. However, the required high inductance values which make the on-chip integration of the power amplifier difficult. The designed power amplifier is fully integrated in the remotely powered sensor system and fabricated in 0.18 μm CMOS process. The power is transferred to the implantable sensor system at 13.56 MHz by using an inductively coupled remote powering link. The induced AC voltage on the implant coil is converted into a DC voltage by a passive full-wave rectifier. A voltage regulator is used to suppress the ripples and create a clean and stable 1.8 V supply voltage for the sensor and communication blocks. The data collected from the sensors is transmitted by on-off keying modulated low-power transmitter at 1.2 GHz frequency. The transmitter is composed of a LC tank oscillator and a fully on-chip class-E power amplifier. An additional output network is used for the power amplifier which makes the integration of the power amplifier fully on-chip. The integrated power amplifier with 0.2 V supply voltage has a drain efficiency of 31.5% at -10 dBm output power for 50 Ω load. The measurement results verify the functionality of the power amplifier and the remotely powered implantable sensor system. The data communication is also verified by using a commercial 50 Ω chip antenna and has 600 kbps data rate at 1 m communication distance.

  4. Ac magnetorestriction hysteresis and magnetization direction in grain oriented silicon steels

    SciTech Connect

    Mogi, Hisashi; Matsuo, Yukio; Kumano, Tomoji

    1999-09-01

    A hysteresis curve of ac magnetostriction was measured, magnetizing a grain oriented silicon steel in the direction deviated from rolling direction of a sample. The ac magnetostriction ({lambda} ac) curves were analyzed as harmonics in the interest of noise spectrum of such as a power transformer. The domain structure model in this magnetostriction process was proposed. The hysteresis was large in the magnetization direction inclined at 30 and 90{degree} from the rolling direction.

  5. Channel model for AC electric arc

    NASA Astrophysics Data System (ADS)

    Larsen, H. L.

    1993-06-01

    This report contains the results from calculations of free-burning AC electric arcs in argon. In order to calculate the arc current and arc voltage, the external electric circuit must be taken into consideration. The external circuit is modeled by an equivalent circuit consisting of an ideal AC voltage source, a loss resistance, and an inductance. The qualitative behavior of the current-voltage characteristic is in agreement with observed characteristics, but experimental data are necessary in order to check whether the calculated power loss is reasonable. Non-symmetry was modeled by introducing different anode and cathode falls in the two half periods. An attempt at taking into account different cathode current densities in the two half periods, depending on whether the electrode or silicon melt is cathode, did not give satisfactory results. Thermionic emission was assumed in both half periods, but this may not be the right mechanism when the silicon melt is cathode. The time delay of the AC arc compared to the DC case is modeled by a time constant. It was shown that this preset time constant must be in agreement with the mean 'mechanical' relaxation time in the arc in order to fulfill the energy balance. By updating the time constant until this is achieved, the time constant is eliminated as a parameter that must be chosen a priori.

  6. Differential Roles of AC2 and AC4 of Cassava Geminiviruses in Mediating Synergism and Suppression of Posttranscriptional Gene Silencing

    PubMed Central

    Vanitharani, Ramachandran; Chellappan, Padmanabhan; Pita, Justin S.; Fauquet, Claude M.

    2004-01-01

    Posttranscriptional gene silencing (PTGS) in plants is a natural defense mechanism against virus infection. In mixed infections, virus synergism is proposed to result from suppression of the host defense mechanism by the viruses. Synergistic severe mosaic disease caused by simultaneous infection with isolates of the Cameroon strain of African cassava mosaic virus (ACMV-[CM]) and East African cassava mosaic Cameroon virus (EACMCV) in cassava and tobacco is characterized by a dramatic increase in symptom severity and a severalfold increase in viral-DNA accumulation by both viruses compared to that in singly infected plants. Here, we report that synergism between ACMV-[CM] and EACMCV is a two-way process, as the presence of the DNA-A component of ACMV-[CM] or EACMCV in trans enhanced the accumulation of viral DNA of EACMCV and ACMV-[CM], respectively, in tobacco BY-2 protoplasts. Furthermore, transient expression of ACMV-[CM] AC4 driven by the Cauliflower mosaic virus 35S promoter (p35S-AC4) enhanced EACMCV DNA accumulation by ∼8-fold in protoplasts, while p35S-AC2 of EACMCV enhanced ACMV-[CM] DNA accumulation, also by ∼8-fold. An Agrobacterium-based leaf infiltration assay determined that ACMV-[CM] AC4 and EACMCV AC2, the putative synergistic genes, were able to suppress PTGS induced by green fluorescent protein (GFP) and eliminated the short interfering RNAs associated with PTGS, with a correlated increase in GFP mRNA accumulation. In addition, we have identified AC4 of Sri Lankan cassava mosaic virus and AC2 of Indian cassava mosaic virus as suppressors of PTGS, indicating that geminiviruses evolved differently in regard to interaction with the host. The specific and different roles played by these AC2 and AC4 proteins of cassava geminiviruses in regulating anti-PTGS activity and their relation to synergism are discussed. PMID:15308741

  7. Predictions of U.K. regulated power station contributions to regional air pollution and deposition: a model comparison exercise.

    PubMed

    Chemel, Charles; Sokhi, Ranjeet S; Dore, Anthony J; Sutton, Paul; Vincent, Keith J; Griffiths, Stephen J; Hayman, Garry D; Wright, Raymond D; Baggaley, Matthew; Hallsworth, Stephen; Prain, H Douglas; Fisher, Bernard E A

    2011-11-01

    Contributions of the emissions from a U.K. regulated fossil-fuel power station to regional air pollution and deposition are estimated using four air quality modeling systems for the year 2003. The modeling systems vary in complexity and emphasis in the way they treat atmospheric and chemical processes, and include the Community Multiscale Air Quality (CMAQ) modeling system in its versions 4.6 and 4.7, a nested modeling system that combines long- and short-range impacts (referred to as TRACK-ADMS [Trajectory Model with Atmospheric Chemical Kinetics-Atmospheric Dispersion Modelling System]), and the Fine Resolution Atmospheric Multi-pollutant Exchange (FRAME) model. An evaluation of the baseline calculations against U.K. monitoring network data is performed. The CMAQ modeling system version 4.6 data set is selected as the reference data set for the model footprint comparison. The annual mean air concentration and total deposition footprints are summarized for each modeling system. The footprints of the power station emissions can account for a significant fraction of the local impacts for some species (e.g., more than 50% for SO2 air concentration and non-sea-salt sulfur deposition close to the source) for 2003. The spatial correlation and the coefficient of variation of the root mean square error (CVRMSE) are calculated between each model footprint and that calculated by the CMAQ modeling system version 4.6. The correlation coefficient quantifies model agreement in terms of spatial patterns, and the CVRMSE measures the magnitude of the difference between model footprints. Possible reasons for the differences between model results are discussed. Finally, implications and recommendations for the regulatory assessment of the impact of major industrial sources using regional air quality modeling systems are discussed in the light of results from this case study.

  8. Power conditioning system for energy sources

    DOEpatents

    Mazumder, Sudip K.; Burra, Rajni K.; Acharya, Kaustuva

    2008-05-13

    Apparatus for conditioning power generated by an energy source includes an inverter for converting a DC input voltage from the energy source to a square wave AC output voltage, and a converter for converting the AC output voltage from the inverter to a sine wave AC output voltage.

  9. AC Conductivity Studies of Lithium Based Phospho Vanadate Glasses

    NASA Astrophysics Data System (ADS)

    Nagendra, K.; Babu, G. Satish; Reddy, C. Narayana; Gowda, Veeranna

    2011-07-01

    Glasses in the system xLi2SO4-20Li2O-(80-x) [80P2O5-20V2O5] (5⩾x⩾20 mol%) has been prepared by melt quenching method. Dc and ac conductivity has been studied over a wide range of frequency (10 Hz to 10 MHz) and temperature (298 K-523 K). The dc conductivity found to increase with increase of Li2SO4 concentration. The ac conductivities have been fitted to the Almond-West type single power law equation σ(ω) = σ(0)+Aωs where `s' is the power law exponent. The ac conductivity found to increase with increase of Li2SO4 concentration. An attempt is made to elucidate the enhancement of lithium ion conduction in phosphor-vanadate glasses by considering the expansion of network structure.

  10. Layoff Handling Still Lags ACS Standards.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1981

    1981-01-01

    Reviews termination procedures of professional chemists and the compliance of these terminations to the American Chemical Society's (ACS's) Professional Employment Guidelines. Provides the ACS guidelines. (DS)

  11. AC photovoltaic module magnetic fields

    SciTech Connect

    Jennings, C.; Chang, G.J.; Reyes, A.B.; Whitaker, C.M.

    1997-12-31

    Implementation of alternating current (AC) photovoltaic (PV) modules, particularly for distributed applications such as PV rooftops and facades, may be slowed by public concern about electric and magnetic fields (EMF). This paper documents magnetic field measurements on an AC PV module, complementing EMF research on direct-current PV modules conducted by PG and E in 1993. Although not comprehensive, the PV EMF data indicate that 60 Hz magnetic fields (the EMF type of greatest public concern) from PV modules are comparable to, or significantly less than, those from household appliances. Given the present EMF research knowledge, AC PV module EMF may not merit considerable concern.

  12. Bearingless AC Homopolar Machine Design and Control for Distributed Flywheel Energy Storage

    NASA Astrophysics Data System (ADS)

    Severson, Eric Loren

    The increasing ownership of electric vehicles, in-home solar and wind generation, and wider penetration of renewable energies onto the power grid has created a need for grid-based energy storage to provide energy-neutral services. These services include frequency regulation, which requires short response-times, high power ramping capabilities, and several charge cycles over the course of one day; and diurnal load-/generation-following services to offset the inherent mismatch between renewable generation and the power grid's load profile, which requires low self-discharge so that a reasonable efficiency is obtained over a 24 hour storage interval. To realize the maximum benefits of energy storage, the technology should be modular and have minimum geographic constraints, so that it is easily scalable according to local demands. Furthermore, the technology must be economically viable to participate in the energy markets. There is currently no storage technology that is able to simultaneously meet all of these needs. This dissertation focuses on developing a new energy storage device based on flywheel technology to meet these needs. It is shown that the bearingless ac homopolar machine can be used to overcome key obstacles in flywheel technology, namely: unacceptable self-discharge and overall system cost and complexity. Bearingless machines combine the functionality of a magnetic bearing and a motor/generator into a single electromechanical device. Design of these machines is particularly challenging due to cross-coupling effects and trade-offs between motor and magnetic bearing capabilities. The bearingless ac homopolar machine adds to these design challenges due to its 3D flux paths requiring computationally expensive 3D finite element analysis. At the time this dissertation was started, bearingless ac homopolar machines were a highly immature technology. This dissertation advances the state-of-the-art of these machines through research contributions in the areas of

  13. A Tariff for Reactive Power

    SciTech Connect

    Kueck, John D; Kirby, Brendan J; Li, Fangxing; Tufon, Christopher; Isemonger, Alan

    2008-07-01

    Two kinds of power are required to operate an electric power system: real power, measured in watts, and reactive power, measured in volt-amperes reactive or VARs. Reactive power supply is one of a class of power system reliability services collectively known as ancillary services, and is essential for the reliable operation of the bulk power system. Reactive power flows when current leads or lags behind voltage. Typically, the current in a distribution system lags behind voltage because of inductive loads such as motors. Reactive power flow wastes energy and capacity and causes voltage droop. To correct lagging power flow, leading reactive power (current leading voltage) is supplied to bring the current into phase with voltage. When the current is in phase with voltage, there is a reduction in system losses, an increase in system capacity, and a rise in voltage. Reactive power can be supplied from either static or dynamic VAR sources. Static sources are typically transmission and distribution equipment, such as capacitors at substations, and their cost has historically been included in the revenue requirement of the transmission operator (TO), and recovered through cost-of-service rates. By contrast, dynamic sources are typically generators capable of producing variable levels of reactive power by automatically controlling the generator to regulate voltage. Transmission system devices such as synchronous condensers can also provide dynamic reactive power. A class of solid state devices (called flexible AC transmission system devices or FACTs) can provide dynamic reactive power. One specific device has the unfortunate name of static VAR compensator (SVC), where 'static' refers to the solid state nature of the device (it does not include rotating equipment) and not to the production of static reactive power. Dynamic sources at the distribution level, while more costly would be very useful in helping to regulate local voltage. Local voltage regulation would reduce

  14. Variable-frequency inverter controls torque, speed, and braking in ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1974-01-01

    Dc to ac inverter provides optimum frequency and voltage to ac induction motor, in response to different motor-load and speed requirements. Inverter varies slip frequency of motor in proportion to required torque. Inverter protects motor from high current surges, controls negative slip to apply braking, and returns energy stored in momentum of load to dc power source.

  15. Design & development fo a 20-MW flywheel-based frequency regulation power plant : a study for the DOE Energy Storage Systems program.

    SciTech Connect

    Rounds, Robert; Peek, Georgianne Huff

    2009-01-01

    This report describes the successful efforts of Beacon Power to design and develop a 20-MW frequency regulation power plant based solely on flywheels. Beacon's Smart Matrix (Flywheel) Systems regulation power plant, unlike coal or natural gas generators, will not burn fossil fuel or directly produce particulates or other air emissions and will have the ability to ramp up or down in a matter of seconds. The report describes how data from the scaled Beacon system, deployed in California and New York, proved that the flywheel-based systems provided faster responding regulation services in terms of cost-performance and environmental impact. Included in the report is a description of Beacon's design package for a generic, multi-MW flywheel-based regulation power plant that allows accurate bids from a design/build contractor and Beacon's recommendations for site requirements that would ensure the fastest possible construction. The paper concludes with a statement about Beacon's plans for a lower cost, modular-style substation based on the 20-MW design.

  16. Diagnostics of the Fermilab Tevatron using an AC dipole

    SciTech Connect

    Miyamoto, Ryoichi

    2008-08-01

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

  17. 17 CFR 240.17Ac3-1 - Withdrawal from registration with the Commission.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Withdrawal from registration with the Commission. 240.17Ac3-1 Section 240.17Ac3-1 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, SECURITIES EXCHANGE ACT OF 1934 Rules...

  18. Substituted Phthalimide AC94377 Is a Selective Agonist of the Gibberellin Receptor GID11[OPEN

    PubMed Central

    Otani, Masato; Shimotakahara, Hiroaki; Yoon, Jung-Min; Park, Seung-Hyun; Miyaji, Tomoko; Nakano, Takeshi; Nakamura, Hidemitsu; Nakajima, Masatoshi

    2017-01-01

    Gibberellin (GA) is a major plant hormone that regulates plant growth and development and is widely used as a plant growth regulator in agricultural production. There is an increasing demand for function-limited GA mimics due to the limitations on the agronomical application of GA to crops, including GA’s high cost of producing and its leading to the crops’ lodging. AC94377, a substituted phthalimide, is a chemical that mimics the growth-regulating activity of GAs in various plants, despite its structural difference. Although AC94377 is widely studied in many weeds and crops, its mode of action as a GA mimic is largely unknown. In this study, we confirmed that AC94377 displays GA-like activities in Arabidopsis (Arabidopsis thaliana) and demonstrated that AC94377 binds to the Arabidopsis GIBBERELLIN INSENSITIVE DWARF1 (GID1) receptor (AtGID1), forms the AtGID1-AC94377-DELLA complex, and induces the degradation of DELLA protein. Our results also indicated that AC94377 is selective for a specific subtype among three AtGID1s and that the selectivity of AC94377 is attributable to a single residue at the entrance to the hydrophobic pocket of GID1. We conclude that AC94377 is a GID1 agonist with selectivity for a specific subtype of GID1, which could be further developed and used as a function-limited regulator of plant growth in both basic study and agriculture. PMID:27899534

  19. Theoretical analysis on ac susceptibility measurements of superconductor tapes

    NASA Astrophysics Data System (ADS)

    Chen, Du-Xing; Sun, Yue-Ming; Li, Shuo; Fang, Jin

    2017-02-01

    Perpendicular ac susceptibility χ ={χ\\prime}-j{χ\\prime \\prime} of a superconducting long tape defined by magnetic moment and determined inductively by magnetic flux is calculated using Brandt’s technique from a power-law dependence of electric field on sheet current density. The requirements of χ measurements to the experimental setup and procedure are discussed based on the calculation results.

  20. 23. AC GENERATOR, ALLISCHALMERS SN #1246797, MFG. MILWAUKEE, KW 1600 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. AC GENERATOR, ALLIS-CHALMERS SN #1246797, MFG. MILWAUKEE, KW 1600 PF 80 C/O VOLTS 2300 AMPS 503 CY 60 PH 3 RMP 164 EXC VOLTS 125 AMPS MAN 300 - Columbia Canal & Power Plant, Waterfront of Broad River, Columbia, Richland County, SC

  1. Ac loss calorimeter for three-phase cable

    SciTech Connect

    Daney, D.E.; Boenig, H.J.; Maley, M.P.; McMurry, D.E.; DeBlanc, B.G.

    1996-10-01

    A calorimeter for measuring ac losses in meter-long lengths of HTS superconducting power transmission line cables is described. The calorimeter, which is based on a temperature difference technique, has a precision of 1 mW and measures single, two-phase (coupling), and three-phase losses. The measurements show significant coupling losses between phases.

  2. 14. VIEW OF AIR COMPRESSOR. 1500 kw Westinghouse AC generator ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. VIEW OF AIR COMPRESSOR. 1500 kw Westinghouse AC generator steam-turbine unit; beyond is air compressor of Chicago Pneumatic Tool Company, 1920, engineered by Earl E. Know Company, Erie, Pennsylvania. - Juniata Shops, Power Plant & Boiler House, East of Fourth Avenue at Second Street, Altoona, Blair County, PA

  3. Low-power output-capacitorless low-dropout regulator with adjustable charge injection technique for on-off-keying transmitters

    NASA Astrophysics Data System (ADS)

    Akita, Ippei; Asai, Shochi; Ishida, Makoto

    2014-01-01

    In this paper a low-power low-dropout (LDO) regulator for p power amplifier (PA) in on-off-keying (OOK) transmitters is proposed. The proposed technique needs no external output capacitors, enabling small-area and low-cost implementation. The response of a rapid load change in an OOK transmitter is improved by the proposed adjustable charge injection (ACI) technique that uses timing information of a transmitted data signal. The designed regulator with the ACI technique has been fabricated in a standard 180 nm CMOS process and achieves 100 mVpp dropout voltage ripple. The measured current dissipation is 65 µA at a power supply of 1.8 V.

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

    SciTech Connect

    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 more and more

  5. Isolation of an acetyl-CoA synthetase gene (ZbACS2) from Zygosaccharomyces bailii.

    PubMed

    Rodrigues, Fernando; Zeeman, Anne-Marie; Cardoso, Helena; Sousa, Maria João; Steensma, H Yde; Côrte-Real, Manuela; Leão, Cecília

    2004-03-01

    A gene homologous to Saccharomyces cerevisiae ACS genes, coding for acetyl-CoA synthetase, has been cloned from the yeast Zygosaccharomyces bailii ISA 1307, by using reverse genetic approaches. A probe obtained by PCR amplification from Z. bailii DNA, using primers derived from two conserved regions of yeast ACS proteins, RIGAIHSVVF (ScAcs1p; 210-219) and RVDDVVNVSG (ScAcs1p; 574-583), was used for screening a Z. bailii genomic library. Nine clones with partially overlapping inserts were isolated. The sequenced DNA fragment contains a complete ORF of 2027 bp (ZbACS2) and the deduced polypeptide shares significant homologies with the products of ACS2 genes from S. cerevisiae and Kluyveromyces lactis (81% and 82% identity and 84% and 89% similarity, respectively). Phylogenetic analysis shows that the sequence of Zbacs2 is more closely related to the sequences from Acs2 than to those from Acs1 proteins. Moreover, this analysis revealed that the gene duplication producing Acs1 and Acs2 proteins has occurred in the common ancestor of S. cerevisiae, K. lactis, Candida albicans, C. glabrata and Debaryomyces hansenii lineages. Additionally, the cloned gene allowed growth of S. cerevisiae Scacs2 null mutant, in medium containing glucose as the only carbon and energy source, indicating that it encodes a functional acetyl-CoA synthetase. Also, S. cerevisiae cells expressing ZbACS2 have a shorter lag time, in medium containing glucose (2%, w/v) plus acetic acid (0.1-0.35%, v/v). No differences in cell response to acetic acid stress were detected both by specific growth and death rates. The mode of regulation of ZbACS2 appears to be different from ScACS2 and KlACS2, being subject to repression by a glucose pulse in acetic acid-grown cells.

  6. 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

    SciTech Connect

    Stern, M.; West, R.; Fourer, G.; Whalen, W.; Van Loo, M.; Duran, G.

    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.

  7. The 8.4 MW Modulator/Regulator Power Systems for the Electron Cyclotron Heating Facility Upgrade at DIII-D

    SciTech Connect

    S.G.E. Pronko; D.S. Baggest

    1999-12-01

    Over the next three years the DIII-D National Fusion Facility at General Atomics will upgrade its electron cyclotron heating (ECH) capability from the present 3 MW at 110 GHz to 10 MW of injected microwave power. There will be ten gyrotron tubes supplied by five 8.4 MW modulator/regulator (M/R) power systems. The project has gained considerable leverage from the acquisition of surplus hardware from the MFTF program that was conducted at LLNL in the early 1980s. One of these systems had been refurbished and converted for use as an ECH power supply earlier. The experience gained and the lessons learned from operating that system have proved valuable in guiding the engineering of the new systems. This paper provides an overview of the power system design and a report on the present status of the project.

  8. Alameda-Contra Costa Transit District (AC Transit) Fuel Cell Transit Buses: Preliminary Evaluation Results

    SciTech Connect

    Chandler, K.; Eudy, L.

    2007-03-01

    This report provides an evaluation of three prototype fuel cell-powered transit buses operating at AC Transit in Oakland, California, and six baseline diesel buses similar in design to the fuel cell buses.

  9. How Much DC Power is Necessary

    DTIC Science & Technology

    2010-04-01

    must transform essentially all of the available AC power to DC, including all of the power for the ship propulsion drive. This approach by the...in Fig. 1 convert the AC source power to DC and energize the associated DC busses. At the power levels anticipated, i.e., for ship propulsion load...for a ship propulsion application. We begin by assuming that the variable frequency power electronics associated with the rotor will only deliver

  10. Resveratrol inhibits mucus overproduction and MUC5AC expression in a murine model of asthma.

    PubMed

    Ni, Zhen-Hua; Tang, Ji-Hong; Chen, Guo; Lai, Yi-Min; Chen, Qing-Ge; Li, Zao; Yang, Wei; Luo, Xu-Min; Wang, Xiong-Biao

    2016-01-01

    Previous in vitro studies have demonstrated that resveratrol is able to significantly inhibit the upregulation of mucin 5AC (MUC5AC), a major component of mucus; thus indicating that resveratrol may have potential in regulating mucus overproduction. However, there have been few studies regarding the resveratrol‑mediated prevention of MUC5AC overproduction in vivo, and the mechanisms by which resveratrol regulates MUC5AC expression have yet to be elucidated. In the present study, an ovalbumin (OVA)‑challenged murine model of asthma was used to assess the effects of resveratrol treatment on mucus production in vivo. The results demonstrated that resveratrol significantly inhibited OVA‑induced airway inflammation and mucus production. In addition, the mRNA and protein expression levels of MUC5AC were increased in the OVA‑challenged mice, whereas treatment with resveratrol significantly inhibited this effect. The expression levels of murine calcium‑activated chloride channel (mCLCA)3, an important key mediator of MUC5AC production, were also reduced following resveratrol treatment. Furthermore, in vitro studies demonstrated that resveratrol significantly inhibited human (h)CLCA1 and MUC5AC expression in a dose‑dependent manner. These results indicated that resveratrol was effective in preventing mucus overproduction and MUC5AC expression in vivo, and its underlying mechanism may be associated with regulation of the mCLCA3/hCLCA1 signaling pathway.

  11. NONLINEAR DIAGNOSTICS USING AC DIPOLES.

    SciTech Connect

    PEGGS,S.

    1999-03-29

    There are three goals in the accurate nonlinear diagnosis of a storage ring. First, the beam must be moved to amplitudes many times the natural beam size. Second, strong and long lasting signals must be generated. Third, the measurement technique should be non-destructive. Conventionally, a single turn kick moves the beam to large amplitudes, and turn-by-turn data are recorded from multiple beam position monitors (BPMs) [1-6]. Unfortunately, tune spread across the beam causes the center of charge beam signal to ''decohere'' on a time scale often less than 100 turns. Filamentation also permanently destroys the beam emittance (in a hadron ring). Thus, the ''strong single turn kick'' technique successfully achieves only one out of the three goals. AC dipole techniques can achieve all three. Adiabatically excited AC dipoles slowly move the beam out to large amplitudes. The coherent signals then recorded last arbitrarily long. The beam maintains its original emittance if the AC dipoles are also turned off adiabatically, ready for further use. The AGS already uses an RF dipole to accelerate polarized proton beams through depolarizing resonances with minimal polarization loss [7]. Similar AC dipoles will be installed in the horizontal and vertical planes of both rings in RHIC [8]. The RHIC AC dipoles will also be used as spin flippers, and to measure linear optical functions [9].

  12. Static DC to DC Power Conditioning-Active Ripple Filter, 1 MHZ DC to DC Conversion, and Nonlinear Analysis. Ph.D. Thesis; [voltage regulation and conversion circuitry for spacecraft power supplies

    NASA Technical Reports Server (NTRS)

    Sander, W. A., III

    1973-01-01

    Dc to dc static power conditioning systems on unmanned spacecraft have as their inputs highly fluctuating dc voltages which they condition to regulated dc voltages. These input voltages may be less than or greater than the desired regulated voltages. The design of two circuits which address specific problems in the design of these power conditioning systems and a nonlinear analysis of one of the circuits are discussed. The first circuit design is for a nondissipative active ripple filter which uses an operational amplifier to amplify and cancel the sensed ripple voltage. A dc to dc converter operating at a switching frequency of 1 MHz is the second circuit discussed. A nonlinear analysis of the type of dc to dc converter utilized in designing the 1 MHz converter is included.

  13. Direct current power delivery system and method

    DOEpatents

    Zhang, Di; Garces, Luis Jose; Dai, Jian; Lai, Rixin

    2016-09-06

    A power transmission system includes a first unit for carrying out the steps of receiving high voltage direct current (HVDC) power from an HVDC power line, generating an alternating current (AC) component indicative of a status of the first unit, and adding the AC component to the HVDC power line. Further, the power transmission system includes a second unit for carrying out the steps of generating a direct current (DC) voltage to transfer the HVDC power on the HVDC power line, wherein the HVDC power line is coupled between the first unit and the second unit, detecting a presence or an absence of the added AC component in the HVDC power line, and determining the status of the first unit based on the added AC component.

  14. Superconducting shielded core reactor with reduced AC losses

    DOEpatents

    Cha, Yung S.; Hull, John R.

    2006-04-04

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

  15. Combined Heat and Power (CHP) as a Compliance Option under the Clean Power Plan: A Template and Policy Options for State Regulators

    SciTech Connect

    2015-07-30

    Combined Heat and Power (CHP) is an important option for states to consider in developing strategies to meet their emission targets under the US Environmental Protection Agency's Clean Power Plan. This Template is designed to highlight key issues that states should consider when evaluating whether CHP could be a meaningful component of their compliance plans. It demonstrates that CHP can be a valuable approach for reducing emissions and helping states achieve their targets. While the report does not endorse any particular approach for any state, and actual plans will vary dependent upon state-specific factors and determinations, it provides tools and resources that states can use to begin the process, and underscores the opportunity CHP represents for many states. . By producing both heat and electricity from a single fuel source, CHP offers significant energy savings and carbon emissions benefits over the separate generation of heat and power, with a typical unit producing electricity with half the emissions of conventional generation. These efficiency gains translate to economic savings and enhanced competitiveness for CHP hosts, and emissions reductions for the state, along with helping to lower electric bills; and creating jobs in the design, construction, installation and maintenance of equipment. In 2015, CHP represents 8 percent of electric capacity in the United States and provides 12 percent of total power generation. Projects already exist in all 50 states, but significant technical and economic potential remains. CHP offers a tested way for states to achieve their emission limits while advancing a host of ancillary benefits.

  16. An Actual Design of AC Filter for Static Var Compensator and Verification Results from the Field Test

    NASA Astrophysics Data System (ADS)

    Tamura, Yuji; Takasaki, Shinji; Irokawa, Shoichi; Takeda, Hideo; Takagi, Kikuo; Noro, Yasuhiro; Ametani, Akihiro

    AC filter design method for SVC and HVDC is commonly known in the relevant CIGRE technical brochure and IEC technical report. However the conventional method requires many iterative calculations of the harmonic voltages and currents until the calculation results become within the regulation levels by changing filter parameters based on the experience. In this respect, a new improved design method is proposed, which enables efficient evaluation on the complex impedance plane to confirm as to whether the proposed filter impedance is in the permissible range. In an actual project of Okuura SVC of Kyusyu Electric Power Co., Inc., the new method was applied to the AC filter design. This paper describes on the actual procedure of the AC filter design with the new method, the actual references of the harmonic performance calculation, and the field test measurement results on Okuura SVC. The calculation results and the filed measurement results are consistent with each other, thus the validity of the new design method is verified on its accuracy and effectiveness.

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

    NASA Technical Reports Server (NTRS)

    Slicker, J. M.

    1983-01-01

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

  18. Optimal Power Flow Pursuit

    SciTech Connect

    Dall'Anese, Emiliano

    2016-08-01

    Past works that focused on addressing power-quality and reliability concerns related to renewable energy resources (RESs) operating with business-as-usual practices have looked at the design of Volt/VAr and Volt/Watt strategies to regulate real or reactive powers based on local voltage measurements, so that terminal voltages are within acceptable levels. These control strategies have the potential of operating at the same time scale of distribution-system dynamics, and can therefore mitigate disturbances precipitated fast time-varying loads and ambient conditions; however, they do not necessarily guarantee system-level optimality, and stability claims are mainly based on empirical evidences. On a different time scale, centralized and distributed optimal power flow (OPF) algorithms have been proposed to compute optimal steady-state inverter setpoints, so that power losses and voltage deviations are minimized and economic benefits to end-users providing ancillary services are maximized. However, traditional OPF schemes may offer decision making capabilities that do not match the dynamics of distribution systems. Particularly, during the time required to collect data from all the nodes of the network (e.g., loads), solve the OPF, and subsequently dispatch setpoints, the underlying load, ambient, and network conditions may have already changed; in this case, the DER output powers would be consistently regulated around outdated setpoints, leading to suboptimal system operation and violation of relevant electrical limits. The present work focuses on the synthesis of distributed RES-inverter controllers that leverage the opportunities for fast feedback offered by power-electronics interfaced RESs. The overarching objective is to bridge the temporal gap between long-term system optimization and real-time control, to enable seamless RES integration in large scale with stability and efficiency guarantees, while congruently pursuing system-level optimization objectives. The

  19. A novel flattop current regulated energy discharge type pulsed power supply and magnet yielding 4. 4 kGauss-meter for 6 milliseconds

    SciTech Connect

    Visser, A.T.

    1989-07-01

    Most energy discharge power supplies obtain their bursts of power from the energy stored in charged capacitors when it is suddenly released into a load. This note describes the design of a similar small 800 Joules energy discharge type power supply and magnet. The magnet gap is 2 in.{times}2 in.{times}25-1/2 in. long and produces about 4.4 kGauss-meters at a rate of 12 pulses per minute. Each pulse is current regulated at the top for a duration of 6 msec. and varies less than 0.6% of set value. Current regulation at flattop is obtained by switching a resistor in and out of the discharge circuit with an IGBT at a rate of about 5 kHz. Most energy discharge systems produce half sine wave pulses, and current regulation is obtained by controlling the charge voltage at the energy storage capacitor, resulting only in a controlled peak current value of the half sine wave pulse. The current value at the top changes substantially during 6 msec. depending on the operating frequency.

  20. A novel four-quadrant power supply for low-energy correction magnets

    NASA Astrophysics Data System (ADS)

    García-Gil, R.; Espí, J. M.; Voelker, F.; Dede, E. J.; Castelló, J.

    2003-09-01

    This paper describes an efficient power supply to feed low-energy correction magnets in particle accelerator applications, where a controlled current with trapezoidal profile and four-quadrant operation is needed. The selected design is based on an AC-DC matrix converter topology, which uses the Space Vector Modulation (SVM) technique to obtain a near unity power factor at the AC input and output DC current regulation. This topology allows performing high-frequency isolation, while four-quadrant operation is maintained, and reducing volume and weight as compared with the classical thyristor (SCR)-based technology. Control tasks are implemented on an all-digital control card: output current regulation is accomplished in a digital signal processor device and SVM is implemented in a Field-Programmable Gate-Array. Simulations and experimental results of a 1.2 kW prototype validate the design.

  1. Performance optimization for doubly fed wind power generation systems

    SciTech Connect

    Bhowmik, S.; Spee, R.; Enslin, J.H.R.

    1999-08-01

    Significant variation of the resource kinetic energy, in the form of wind speed, results in substantially reduced energy capture in a fixed-speed wind turbine. In order to increase the wind energy capture in the turbine, variable-speed generation (VSG) strategies have been proposed and implemented. However, that requires an expensive ac/ac power converter, which increases the capital investment significantly. Consequently, doubly fed systems have been proposed to reduce the size of the power converter and, thereby, the associated cost. Additionally, in doubly fed systems, as a fixed operating point (power and speed), power flow can be regulated between the two winding systems on the machine. This feature can by utilized to essentially minimize losses in the machine associated with the given operating point or achieve other desired performance enhancements. In this paper, a brushless doubly fed machine (BDFM) is utilized to develop a VSG wind power generator. The VSG controller employs a wind-speed-estimation-based maximum power point tracker and a heuristic-model-based maximum efficiency point tracker to optimize the power output of the system. The controller has been verified for efficacy on a 1.5-kW laboratory VSG wind generator. The strategy is applicable to all doubly fed configurations, including conventional wound-rotor induction machines, Scherbius cascades, BDFM's and doubly fed reluctance machines.

  2. AC Cable: Yokohama Project

    NASA Astrophysics Data System (ADS)

    Masuda, Takato

    High Temperature Superconducting (HTS) cables can transmit large amounts of electricity in a compact size with minimal losses. Therefore, they are expected to save the construction cost of underground lines in urban areas and decrease transmission losses. Several HTS cables have recently been demonstrated in networks around the world, and full-scale commercialization is expected in the near future. In Japan, the development of compact HTS cables suitable for urban deployment has been underway since the early 1990s. In 2007, a national project was started to verify their operational performance and long-term reliability in the grid. An HTS cable 240 m long was installed at the Asahi substation of the Tokyo Electric Power Company (TEPCO) in Yokohama; then a joint, terminations and cooling system was constructed in 2011. After successful performance tests, the cable was connected to the grid for the first time in Japan, and started to deliver electricity to 70,000 households in October 2012. This trouble-free in-grid service continued for over a year. We can conclude that the HTS cable system performs well and has the stability required for long-term in-grid operations.

  3. New power-conditioning systems for superconducting magnetic energy storage

    NASA Astrophysics Data System (ADS)

    Han, Byung Moon

    1992-06-01

    This dissertation presents the development of new power-conditioning systems for superconducting magnetic energy storage (SMES), which can regulate fast and independently the active and reactive powers demanded in the ac network. Three new power-conditioning systems were developed through a systematic approach to match the requirements of the superconducting coil and the ac power network. Each of these new systems is composed of ten 100-MW modules connected in parallel to handle the large current through the superconducting coil. The first system, which was published in the IEEE Transactions on Energy Conversion, consists of line-commutated 24-pulse converter, a thyristor-switched tap-changing transformer, and a thyristor-switched capacitor bank. The second system, which was accepted for publication in the IEEE Transactions on Energy Conversion, consists of a 12-pulse GTO (gate turn-off thyristor) converter and a thyristor-switched tap-changing transformer. The third system, which was submitted to the International Journal of Energy System, consists of a dc chopper and a voltage-source PWM (pulse width modulation) converter. The operational concept of each new system is verified through mathematical analyses and computer simulations. The dynamic interaction of each new system with the ac network and the superconducting coil is analyzed using a simulation model with EMTP (electro-magnetic transients program). The analysis results prove that each new system is feasible and realizable. Each system can regulate the active and reactive powers of the utility network rapidly and independently, and each offer a significant reduction of the system rating by reducing the reactive power demand in the converter. Feasible design for each new system was introduced using a modular design approach based on the 1000 MW/5000 MWH plant, incorporating commercially available components and proven technologies.

  4. ACS from development to operations

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  5. Simple Equipment for Imaging AC.

    ERIC Educational Resources Information Center

    Kamata, Masahiro; Anayama, Takayuki

    2003-01-01

    Presents an effective way to demonstrate the difference between direct current and alternating current using red and green LEDs. Describes how to make a tool that shows how an AC voltage changes with time using the afterimage effect of the LEDs. (Author/NB)

  6. Description of a 20 Kilohertz power distribution system

    NASA Technical Reports Server (NTRS)

    Hansen, I. G.

    1986-01-01

    A single phase, 440 VRMS, 20 kHz power distribution system with a regulated sinusoidal wave form is discussed. A single phase power system minimizes the wiring, sensing, and control complexities required in a multi-sourced redundantly distributed power system. The single phase addresses only the distribution link; mulitphase lower frequency inputs and outputs accommodation techniques are described. While the 440 V operating potential was initially selected for aircraft operating below 50,000 ft, this potential also appears suitable for space power systems. This voltage choice recognizes a reasonable upper limit for semiconductor ratings, yet will direct synthesis of 220 V, 3 power. A 20 kHz operating frequency was selected to be above the range of audibility, minimize the weight of reactive components, yet allow the construction of single power stages of 25 to 30 kW. The regulated sinusoidal distribution system has several advantages. With a regulated voltage, most ac/dc conversions involve rather simple transformer rectifier applications. A sinusoidal distribution system, when used in conjunction with zero crossing switching, represents a minimal source of EMI. The present state of 20 kHz power technology includes computer controls of voltage and/or frequency, low inductance cable, current limiting circuit protection, bi-directional power flow, and motor/generator operating using standard induction machines. A status update and description of each of these items and their significance is presented.

  7. An MRI-Compatible High Frequency AC Resistive Heating System for Homeothermic Maintenance in Small Animals

    PubMed Central

    Gomes, Ana L.; Kinchesh, Paul; Kersemans, Veerle; Allen, Philip D.; Smart, Sean C.

    2016-01-01

    Purpose To develop an MRI-compatible resistive heater, using high frequency alternating current (AC), for temperature maintenance of anaesthetised animals. Materials and Methods An MRI-compatible resistive electrical heater was formed from narrow gauge wire connected to a high frequency (10–100 kHz) AC power source. Multiple gradient echo images covering a range of echo times, and pulse-acquire spectra were acquired with the wire heater powered using high frequency AC or DC power sources and without any current flowing in order to assess the sensitivity of the MRI acquisitions to the presence of current flow through the heater wire. The efficacy of temperature maintenance using the AC heater was assessed by measuring rectal temperature immediately following induction of general anaesthesia for a period of 30 minutes in three different mice. Results Images and spectra acquired in the presence and absence of 50–100 kHz AC through the wire heater were indistinguishable, whereas DC power created field shifts and lineshape distortions. Temperature lost during induction of anaesthesia was recovered within approximately 20 minutes and a stable temperature was reached as the mouse’s temperature approached the set target. Conclusion The AC-powered wire heater maintains adequate heat input to the animal to maintain body temperature, and does not compromise image quality. PMID:27806062

  8. Established and potential physiological roles of bicarbonate-sensing soluble adenylyl cyclase (sAC) in aquatic animals

    PubMed Central

    Tresguerres, Martin; Barott, Katie L.; Barron, Megan E.; Roa, Jinae N.

    2014-01-01

    Soluble adenylyl cyclase (sAC) is a recently recognized source of the signaling molecule cyclic AMP (cAMP) that is genetically and biochemically distinct from the classic G-protein-regulated transmembrane adenylyl cyclases (tmACs). Mammalian sAC is distributed throughout the cytoplasm and it may be present in the nucleus and inside mitochondria. sAC activity is directly stimulated by HCO3−, and sAC has been confirmed to be a HCO3− sensor in a variety of mammalian cell types. In addition, sAC can functionally associate with carbonic anhydrases to act as a de facto sensor of pH and CO2. The two catalytic domains of sAC are related to HCO3−-regulated adenylyl cyclases from cyanobacteria, suggesting the cAMP pathway is an evolutionarily conserved mechanism for sensing CO2 levels and/or acid/base conditions. Reports of sAC in aquatic animals are still limited but are rapidly accumulating. In shark gills, sAC senses blood alkalosis and triggers compensatory H+ absorption. In the intestine of bony fishes, sAC modulates NaCl and water absorption. And in sea urchin sperm, sAC may participate in the initiation of flagellar movement and in the acrosome reaction. Bioinformatics and RT-PCR results reveal that sAC orthologs are present in most animal phyla. This review summarizes the current knowledge on the physiological roles of sAC in aquatic animals and suggests additional functions in which sAC may be involved. PMID:24574382

  9. Established and potential physiological roles of bicarbonate-sensing soluble adenylyl cyclase (sAC) in aquatic animals.

    PubMed

    Tresguerres, Martin; Barott, Katie L; Barron, Megan E; Roa, Jinae N

    2014-03-01

    Soluble adenylyl cyclase (sAC) is a recently recognized source of the signaling molecule cyclic AMP (cAMP) that is genetically and biochemically distinct from the classic G-protein-regulated transmembrane adenylyl cyclases (tmACs). Mammalian sAC is distributed throughout the cytoplasm and it may be present in the nucleus and inside mitochondria. sAC activity is directly stimulated by HCO3(-), and sAC has been confirmed to be a HCO3(-) sensor in a variety of mammalian cell types. In addition, sAC can functionally associate with carbonic anhydrases to act as a de facto sensor of pH and CO2. The two catalytic domains of sAC are related to HCO3(-)-regulated adenylyl cyclases from cyanobacteria, suggesting the cAMP pathway is an evolutionarily conserved mechanism for sensing CO2 levels and/or acid/base conditions. Reports of sAC in aquatic animals are still limited but are rapidly accumulating. In shark gills, sAC senses blood alkalosis and triggers compensatory H(+) absorption. In the intestine of bony fishes, sAC modulates NaCl and water absorption. And in sea urchin sperm, sAC may participate in the initiation of flagellar movement and in the acrosome reaction. Bioinformatics and RT-PCR results reveal that sAC orthologs are present in most animal phyla. This review summarizes the current knowledge on the physiological roles of sAC in aquatic animals and suggests additional functions in which sAC may be involved.

  10. A driving scheme to reduce AC LED flicker

    NASA Astrophysics Data System (ADS)

    Tan, Jianchuan; Narendran, Nadarajah

    2013-09-01

    Light flicker is a common but unwelcome phenomenon in conventional lighting applications. In solid-state lighting, driving or dimming methods also give rise to light flicker. AC LED products in today's marketplace suffer from flicker, which stems from the arrangement of the micro-LEDs and the driving method. Research has shown that light flicker can be a health hazard to humans. Several solutions have been proposed to reduce light flicker in solid-state lighting applications; however, most have drawbacks in terms of power and other performance. This paper proposes a circuit design to reduce light flicker from AC LEDs while maintaining a normal power factor and high power efficiency. The circuit is composed of one resistive branch and one capacitive branch, and each branch drives a load which is made up of high-voltage LEDs. Percent flicker, power factor, and power efficiency were selected as three metrics, and their benchmarks were set to evaluate the performance of this circuit. Phase shift between the two branches was selected as a factor that could determine the circuit performance. The variations of percent flicker, power factor, and power efficiency as a function of phase shift were identified by theoretical analysis and were verified by experiments. The experimental results show that an optimal solution can be achieved for this circuit design at proper phase shift, where the benchmarks of the three metrics are reached.

  11. Abscisic Acid Antagonizes Ethylene Production through the ABI4-Mediated Transcriptional Repression of ACS4 and ACS8 in Arabidopsis.

    PubMed

    Dong, Zhijun; Yu, Yanwen; Li, Shenghui; Wang, Juan; Tang, Saijun; Huang, Rongfeng

    2016-01-04

    Increasing evidence has revealed that abscisic acid (ABA) negatively modulates ethylene biosynthesis, although the underlying mechanism remains unclear. To identify the factors involved, we conducted a screen for ABA-insensitive mutants with altered ethylene production in Arabidopsis. A dominant allele of ABI4, abi4-152, which produces a putative protein with a 16-amino-acid truncation at the C-terminus of ABI4, reduces ethylene production. By contrast, two recessive knockout alleles of ABI4, abi4-102 and abi4-103, result in increased ethylene evolution, indicating that ABI4 negatively regulates ethylene production. Further analyses showed that expression of the ethylene biosynthesis genes ACS4, ACS8, and ACO2 was significantly decreased in abi4-152 but increased in the knockout mutants, with partial dependence on ABA. Chromatin immunoprecipitation-quantitative PCR assays showed that ABI4 directly binds the promoters of these ethylene biosynthesis genes and that ABA enhances this interaction. A fusion protein containing the truncated ABI4-152 peptide accumulated to higher levels than its full-length counterpart in transgenic plants, suggesting that ABI4 is destabilized by its C terminus. Therefore, our results demonstrate that ABA negatively regulates ethylene production through ABI4-mediated transcriptional repression of the ethylene biosynthesis genes ACS4 and ACS8 in Arabidopsis.

  12. ac-resistance-measuring instrument

    SciTech Connect

    Hof, P.J.

    1981-04-22

    An auto-ranging ac resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an ac excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance.

  13. Direct current uninterruptible power supply method and system

    DOEpatents

    Sinha, Gautam

    2003-12-02

    A method and system are described for providing a direct current (DC) uninterruptible power supply with the method including, for example: continuously supplying fuel to a turbine; converting mechanical power from the turbine into alternating current (AC) electrical power; converting the AC electrical power to DC power within a predetermined voltage level range; supplying the DC power to a load; and maintaining a DC load voltage within the predetermined voltage level range by adjusting the amount of fuel supplied to the turbine.

  14. The pineapple AcMADS1 promoter confers high level expression in tomato and arabidopsis flowering and fruiting tissues, but AcMADS1 does not complement the tomato LeMADS-RIN (rin) mutant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A previous EST study identified a MADS box transcription factor coding sequence, AcMADS1, that is strongly induced during non-climacteric pineapple fruit ripening. Phylogenetic analyses place the AcMADS1 protein in the same superclade as LeMADS-RIN, a master regulator of fruit ripening upstream of e...

  15. Measurements of AC Loss In Second-Generation HTS Tapes in a DC Magnetic Field

    NASA Astrophysics Data System (ADS)

    Osofsky, M. S.; Soulen, R. J.; Gubser, D. U.; Datta, T.

    2008-03-01

    The successful application of superconductivity to motors and other power system components depends on the characterization and subsequent minimization of the ac loss in the superconductor used for fabrication of the component. The superconductive component, excited by an ac power source, may be exposed to large dc magnetic fields and/or ac fields. To further complicate the situation, the transport properties of the tapes are strongly dependent on the angle between the applied field and the YBCO c-axis (normal to the tape surface). We report on measurements of the transport ac loss of a YBaCuO tape at 65 K, at several frequencies, in applied dc fields of 1-3 T with the field parallel and perpendicular to the tape normal.

  16. Decrease of magnetic AC loss in twisted-filament Bi-2223 tapes

    NASA Astrophysics Data System (ADS)

    Oomen, M. P.; Rieger, J.; Leghissa, M.; Fischer, B.; Arndt, Th.

    1998-12-01

    In AC power-engineering applications, a large part of the AC loss in the superconductor is due to magnetization by the external field. This magnetic AC loss has been well described for the low- Tc conductors. In Bi-2223 tapes the picture is different due to strong anisotropy, granularity and flux creep. Magnetic AC loss in various twisted and non-twisted Bi-2223 tapes has been measured at power frequencies by a pickup method. The results are compared to theoretical models of magnetization loss. When the field is parallel to the tape plane, the filaments in twisted tapes can be decoupled and the AC loss is decreased even when the matrix is pure silver. The extra effect of higher-resistance matrix materials is studied. In perpendicular field it is more difficult to decouple the filaments, due to the particular tape geometry. Contrary to a wire, there are essential differences between the AC loss mechanisms in a long twisted tape and those in a short piece of non-twisted tape. Finally, the dynamic resistance caused by the AC magnetic field is examined.

  17. Circulation autoantibody against Lamin A/C in patients with Sjögren's syndrome

    PubMed Central

    Chen, Peng; Yang, Chunhe; Gan, Xianfeng; Hussain, Muhammad; Xun, Yiping; Tian, Yaping; Du, Hongwu

    2016-01-01

    Lamin A/C proteins are major components of nuclear laminae and were encoded by the LMNA gene. Recent studies have found that in addition to provides nuclear-membrane strength; it also regulates the gene expression. Lamin A/C has been confirmed as an autoantigen in RA, SLE and vasculitis. Anti-Lamin A/C antibodies also have been found by indirect immunofluorescence method. In this study, we used various research methods to confirm Lamin A/C is an autoantigen in Han Chinese patients with confirmed Sjögren's syndrome (SS). To further investigate the relationship between the autoimmune disease antigens, we compared the amino acid sequence of Lamin A/C epitope and several common antigens' antigenic determinant. As a result, we found that Lamin A/C has similar epitopes with U1RNP. It means that the potential relationship exist between Lamin A/C and U1RNP. Clinical data we collected also showed that anti-Lamin A/C and anti-U1RNP antibodies always appear in same serum sample. Therefore, we speculated that cross-reaction may take place between antigen and potential antigen, which have similar epitope. Then, by epitope spreading, the potential antigen can be a new autoantigen. Our study provided a new thinking for further research about the relationship between autoantigens and their development mechanism in autoimmune diseases. PMID:27835913

  18. Characterization and snubbing of a bidirectional MCT in a resonant ac link converter

    NASA Technical Reports Server (NTRS)

    Lee, Tony; Elbuluk, Malik E.; Zinger, Donald S.

    1993-01-01

    The MOS-Controlled Thyristor (MCT) is emerging as a powerful switch that combines the better characteristics of existing power devices. A study of switching stresses on an MCT switch under zero voltage resonant switching is presented. The MCT is used as a bidirectional switch in an ac/ac pulse density modulated inverter for induction motor drive. Current and voltage spikes are observed and analyzed with variations in the timing of the switching. Different snubber circuit configurations are under investigation to minimize the effect of these transients. The results will be extended to study and test the MCT switching in a medium power (5 hp) induction motor drive.

  19. Dynamic performance of a STATCON at an HVDC inverter feeding a very weak AC system

    SciTech Connect

    Zhuang, Y.; Menzies, R.W.; Nayak, O.B.; Turanli, H.M.

    1996-04-01

    This paper investigates the dynamic performance of the advanced static var compensator or STATCON at a high voltage direct current (HVDC) converter terminal where the ac system has a very low short circuit ratio (SCR). The STATCON is based on a nine-level GTO thyristor inverter. The studies include operating characteristics of the STATCON under various ac and dc disturbances. The simulation results are compared with other types of reactive power compensation options available for such applications. It is shown that the STATCON has clear advantages over the other compensators, in areas such as; fault response time, voltage support ability, and dc recovery, while operating with very weak ac systems.

  20. New levitation scheme with AC superconducting magnet for EDS MAGLEV system

    SciTech Connect

    Kim, D.H.; Lee, J.K.; Hahn, S.Y.; Cha, G.

    1996-09-01

    This paper proposes a new magnetic levitation scheme which is able to generate levitation force for all speeds including a standstill. Auxiliary wheels which are needed in EDS MAGLEV vehicle can be eliminated. This scheme uses AC superconducting magnets to generate levitation force. In this paper, magnetic fields, forces and power dissipations generated by AC magnets moving above a conducting slab are calculated analytically. Results of calculation show characteristics of EDS system with AC magnet, such as levitation force and loss, are superior to those of EDS system with DC magnets for all speeds.

  1. Development of 3 and 5 kW fuel cell power plants

    NASA Astrophysics Data System (ADS)

    Abens, S.; Farooque, M.

    1985-12-01

    Phosphoric acid fuel cell power plants for use as tactical utility power sources have been developed. The power plants operate on 58% methanol-42% water fuel. Two fully automatic 3kW units were built, tested, and delivered. Thermal efficiency was 23% with ac and 26% with dc output. A brassboard 3kW power plant operating on neat methanol was also constructed, tested, and delivered. The methanol-water premix fuel cell power plant operates on a 1:1.3 molar mixture of methanol and water which is converted in a steam reformer, operating at 300 C, to hydrogen-rich product gas. The fuel cell uses 60 to 65% of the hydrogen to produce dc electricity, and the balance is combusted in a burner to supply heat required for the endothermic reforming process. The phosphoric acid fuel cell stack is air-cooled and operates at a temperature of 190 C. The fuel cell power plant is capable of delivering either regulated dc or ac electrical power through the use of interchangeable power conditioners. A microprocessor based controller provides event sequencing and system control during startup, shutdown and operation of the power plant.

  2. AC-coupled front-end for biopotential measurements.

    PubMed

    Spinelli, Enrique Mario; Pallàs-Areny, Ramon; Mayosky, Miguel Angel

    2003-03-01

    AC coupling is essential in biopotential measurements. Electrode offset potentials can be several orders of magnitude larger than the amplitudes of the biological signals of interest, thus limiting the admissible gain of a dc-coupled front end to prevent amplifier saturation. A high-gain input stage needs ac input coupling. This can be achieved by series capacitors, but in order to provide a bias path, grounded resistors are usually included, which degrade the common mode rejection ratio (CMRR). This paper proposes a novel balanced input ac-coupling network that provides a bias path without any connection to ground, thus resulting in a high CMRR. The circuit being passive, it does not limit the differential dc input voltage. Furthermore, differential signals are ac coupled, whereas common-mode voltages are dc coupled, thus allowing the closed-loop control of the dc common mode voltage by means of a driven-right-leg circuit. This makes the circuit compatible with common-mode dc shifting strategies intended for single-supply biopotential amplifiers. The proposed circuit allows the implementation of high-gain biopotential amplifiers with a reduced number of parts, thus resulting in low power consumption. An electrocardiogram amplifier built according to the proposed design achieves a CMRR of 123 dB at 50 Hz.

  3. Power sector policy reforms

    SciTech Connect

    Moscote, R.A. . LAC Technical Dept.)

    1994-06-01

    This article discusses the changes in energy policy of most countries in the Latin American and the Caribbean region. The topics of the article include the new legal and regulatory frameworks being developed, investment, privatized power producers, government regulation, power distribution, power transmission, access to transmission lines, pricing regulations, and increasing capacity of the power systems.

  4. Electric power

    SciTech Connect

    Chase, M.

    1988-01-01

    This text examines the critical problems faced by the electric power industry, shown in the context of a detailed description of the history and development of the industry. A new industry initiative is proposed that will allow for a more effective response to industry fluctuations. Topics covered include developments in power technology federal nuclear power regulation and legislation, environmentalism and conservationism, industry financial problems, capital minimization, and responses to utility responsibility.

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

    NASA Technical Reports Server (NTRS)

    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.

  6. Three-Phase and Six-Phase AC at the Lab Bench

    ERIC Educational Resources Information Center

    Caplan, George M.

    2009-01-01

    Utility companies generate three-phase electric power, which consists of three sinusoidal voltages with phase angles of 0 degrees, 120 degrees, and 240 degrees. The ac generators described in most introductory textbooks are single-phase generators, so physics students are not likely to learn about three-phase power. I have developed a simple way…

  7. Risk-informed regulation and safety management of nuclear power plants--on the prevention of severe accidents.

    PubMed

    Himanen, Risto; Julin, Ari; Jänkälä, Kalle; Holmberg, Jan-Erik; Virolainen, Reino

    2012-11-01

    There are four operating nuclear power plant (NPP) units in Finland. The Teollisuuden Voima (TVO) power company has two 840 MWe BWR units supplied by Asea-Atom at the Olkiluoto site. The Fortum corporation (formerly IVO) has two 500 MWe VVER 440/213 units at the Loviisa site. In addition, a 1600 MWe European Pressurized Water Reactor supplied by AREVA NP (formerly the Framatome ANP--Siemens AG Consortium) is under construction at the Olkiluoto site. Recently, the Finnish Parliament ratified the government Decision in Principle that the utilities' applications to build two new NPP units are in line with the total good of the society. The Finnish utilities, Fenno power company, and TVO company are in progress of qualifying the type of the new nuclear builds. In Finland, risk-informed applications are formally integrated in the regulatory process of NPPs that are already in the early design phase and these are to run through the construction and operation phases all through the entire plant service time. A plant-specific full-scope probabilistic risk assessment (PRA) is required for each NPP. PRAs shall cover internal events, area events (fires, floods), and external events such as harsh weather conditions and seismic events in all operating modes. Special attention is devoted to the use of various risk-informed PRA applications in the licensing of Olkiluoto 3 NPP.

  8. Power inversion design for ocean wave energy harvesting

    NASA Astrophysics Data System (ADS)

    Talebani, Anwar N.

    The needs for energy sources are increasing day by day because of several factors, such as oil depletion, and global climate change due to the higher level of CO2, so the exploration of various renewable energy sources is very promising area of study. The available ocean waves can be utilized as free source of energy as the water covers 70% of the earth surface. This thesis presents the ocean wave energy as a source of renewable energy. By addressing the problem of designing efficient power electronics system to deliver 5 KW from the induction generator to the grid with less possible losses and harmonics as possible and to control current fed to the grid to successfully harvest ocean wave energy. We design an AC-DC full bridge rectifier converter, and a DC-DC boost converter to harvest wave energy from AC to regulated DC. In order to increase the design efficiency, we need to increase the power factor from (0.5-0.6) to 1. This is accomplished by designing the boost converter with power factor correction in continues mode with RC circuit as an input to the boost converter power factor correction. This design results in a phase shift between the input current and voltage of the full bridge rectifier to generate a small reactive power. The reactive power is injected to the induction generator to maintain its functionality by generating a magnetic field in its stator. Next, we design a single-phase pulse width modulator full bridge voltage source DC-AC grid-tied mode inverter to harvest regulated DC wave energy to AC. The designed inverter is modulated by inner current loop, to control current injected to the grid with minimal filter component to maintain power quality at the grid. The simulation results show that our design successfully control the current level fed to the grid. It is noteworthy that the simulated efficiency is higher than the calculated one since we used an ideal switch in the simulated circuit.

  9. System and method for monitoring and controlling stator winding temperature in a de-energized AC motor

    DOEpatents

    Lu, Bin [Kenosha, WI; Luebke, Charles John [Sussex, WI; Habetler, Thomas G [Snellville, GA; Zhang, Pinjia [Atlanta, GA; Becker, Scott K [Oak Creek, WI

    2011-12-27

    A system and method for measuring and controlling stator winding temperature in an AC motor while idling is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of a multi-phase AC motor. The circuit further includes a plurality of switching devices to control current flow and terminal voltages in the multi-phase AC motor and a controller connected to the circuit. The controller is configured to activate the plurality of switching devices to create a DC signal in an output of the motor control device corresponding to an input to the multi-phase AC motor, determine or estimate a stator winding resistance of the multi-phase AC motor based on the DC signal, and estimate a stator temperature from the stator winding resistance. Temperature can then be controlled and regulated by DC injection into the stator windings.

  10. Power converter

    NASA Technical Reports Server (NTRS)

    Black, J. M. (Inventor)

    1981-01-01

    A dc-to-dc converter employs four transistor switches in a bridge to chop dc power from a source, and a voltage multiplying diode rectifying ladder network to rectify and filter the chopped dc power for delivery to a load. The bridge switches are cross coupled in order for diagonally opposite pairs to turn on and off together using RC networks for the cross coupling to achieve the mode of operation of a free running multivibrator, and the diode rectifying ladder is configured to operate in a push-pull mode driven from opposite sides of the multivibrator outputs of the ridge switches. The four transistor switches provide a square-wave output voltage which as a peak-to-peak amplitude that is twice the input dc voltage, and is thus useful as a dc-to-ac inverter.

  11. Characterization and expression profiles of MaACS and MaACO genes from mulberry (Morus alba L.).

    PubMed

    Liu, Chang-ying; Lü, Rui-hua; Li, Jun; Zhao, Ai-chun; Wang, Xi-ling; Diane, Umuhoza; Wang, Xiao-hong; Wang, Chuan-hong; Yu, Ya-sheng; Han, Shu-mei; Lu, Cheng; Yu, Mao-de

    2014-07-01

    1-Aminocyclopropane-1-carboxylic acid synthase (ACS) and 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) are encoded by multigene families and are involved in fruit ripening by catalyzing the production of ethylene throughout the development of fruit. However, there are no reports on ACS or ACO genes in mulberry, partly because of the limited molecular research background. In this study, we have obtained five ACS gene sequences and two ACO gene sequences from Morus Genome Database. Sequence alignment and phylogenetic analysis of MaACO1 and MaACO2 showed that their amino acids are conserved compared with ACO proteins from other species. MaACS1 and MaACS2 are type I, MaACS3 and MaACS4 are type II, and MaACS5 is type III, with different C-terminal sequences. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) expression analysis showed that the transcripts of MaACS genes were strongly expressed in fruit, and more weakly in other tissues. The expression of MaACO1 and MaACO2 showed different patterns in various mulberry tissues. MaACS and MaACO genes demonstrated two patterns throughout the development of mulberry fruit, and both of them were strongly up-regulated by abscisic acid (ABA) and ethephon.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  13. Planarians: a versatile and powerful model system for molecular studies of regeneration, adult stem cell regulation, aging, and behavior.

    PubMed

    Oviedo, Néstor J; Nicolas, Cindy L; Adams, Dany S; Levin, Michael

    2008-10-01

    INTRODUCTIONIn recent years, planarians have been increasingly recognized as an emerging model organism amenable to molecular genetic techniques aimed at understanding complex biological tasks commonly observed among metazoans. Growing evidence suggests that this model organism is uniquely poised to inform us about the mechanisms of tissue regeneration, stem cell regulation, tissue turnover, pharmacological action of diverse drugs, cancer, and aging. This article provides an overview of the planarian model system with special attention to the species Schmidtea mediterranea. Additionally, information is provided about the most popular use of this organism, together with modern genomic resources and technical approaches.

  14. AC Conductivity Studies of Lithium Based Phospho Vanadate Glasses

    SciTech Connect

    Nagendra, K.; Babu, G. Satish; Gowda, Veeranna; Reddy, C. Narayana

    2011-07-15

    Glasses in the system xLi{sub 2}SO{sub 4}-20Li{sub 2}O-(80-x) [80P{sub 2}O{sub 5}-20V{sub 2}O{sub 5}](5{>=}x{>=}20 mol%) has been prepared by melt quenching method. Dc and ac conductivity has been studied over a wide range of frequency (10 Hz to 10 MHz) and temperature (298 K-523 K). The dc conductivity found to increase with increase of Li{sub 2}SO{sub 4} concentration. The ac conductivities have been fitted to the Almond-West type single power law equation {sigma}({omega}) = {sigma}(0)+A{omega}{sup s} where 's' is the power law exponent. The ac conductivity found to increase with increase of Li{sub 2}SO{sub 4} concentration. An attempt is made to elucidate the enhancement of lithium ion conduction in phosphor-vanadate glasses by considering the expansion of network structure.

  15. Measurements of AC Losses and Current Distribution in Superconducting Cables

    SciTech Connect

    Nguyen, Doan A; Ashworth, Stephen P; Duckworth, Robert C; Carter, Bill; Fleshler, Steven

    2011-01-01

    This paper presents our new experimental facility and techniques to measure ac loss and current distribution between the layers for High Temperature Superconducting (HTS) cables. The facility is powered with a 45 kVA three-phase power supply which can provide three-phase currents up to 5 kA per phase via high current transformers. The system is suitable for measurements at any frequency between 20 and 500 Hz to better understand the ac loss mechanisms in HTS cables. In this paper, we will report techniques and results for ac loss measurements carried out on several HTS cables with and without an HTS shielding layer. For cables without a shielding layer, care must be taken to control the effect of the magnetic fields from return currents on loss measurements. The waveform of the axial magnetic field was also measured by a small pick-up coil placed inside a two-layer cable. The temporal current distribution between the layers can be calculated from the waveform of the axial field.

  16. Fabrication of a PMN-PT single crystal-based transcranial Doppler transducer and the power regulation of its detection system.

    PubMed

    Yue, Qingwen; Liu, Dongxu; Wang, Wei; Di, Wenning; Lin, Di; Wang, Xi'an; Luo, Haosu

    2014-12-19

    Doppler sonographic measurement of flow velocity in the basal cerebral arteries through the intact skull was developed using a pulsed Doppler technique and 2 MHz emitting frequency. Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) were chosen to be the piezoelectric transducer material due to their ultrahigh piezoelectric coefficients, high electromechanical coupling coefficients and low dielectric loss. The pulse-echo response of the transducer was measured using the conventional pulse-echo method in a water bath at room temperature. The -6 dB bandwidth of the transducer is 68.4% and the sensitivity is -17.4 dB. In order to get a good match between transducer and detection system, different transmission powers have been regulated by changing the impedance of the transmitting electric circuit. In the middle cerebral artery (MCA) measurement photograph results, as the transmission power is increasing, the detection results become clearer and clearer. A comparison at the same transmission power for different transducers shows that the detection photograph obtained by the crystal transducer was clearer than that obtained with a commercial transducer, which should make it easier for doctors to find the cerebral arteries.

  17. Fabrication of a PMN-PT Single Crystal-Based Transcranial Doppler Transducer and the Power Regulation of Its Detection System

    PubMed Central

    Yue, Qingwen; Liu, Dongxu; Wang, Wei; Di, Wenning; Lin, Di; Wang, Xi'an; Luo, Haosu

    2014-01-01

    Doppler sonographic measurement of flow velocity in the basal cerebral arteries through the intact skull was developed using a pulsed Doppler technique and 2 MHz emitting frequency. Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) were chosen to be the piezoelectric transducer material due to their ultrahigh piezoelectric coefficients, high electromechanical coupling coefficients and low dielectric loss. The pulse-echo response of the transducer was measured using the conventional pulse-echo method in a water bath at room temperature. The −6 dB bandwidth of the transducer is 68.4% and the sensitivity is −17.4 dB. In order to get a good match between transducer and detection system, different transmission powers have been regulated by changing the impedance of the transmitting electric circuit. In the middle cerebral artery (MCA) measurement photograph results, as the transmission power is increasing, the detection results become clearer and clearer. A comparison at the same transmission power for different transducers shows that the detection photograph obtained by the crystal transducer was clearer than that obtained with a commercial transducer, which should make it easier for doctors to find the cerebral arteries. PMID:25536000

  18. Magnetic field regulation control system analysis

    SciTech Connect

    Badelt, Steven W.

    1996-05-01

    This study comprises (1) an analytical characterization of the Cameca ion microscope`s magnetic field regulation circuitry and (2) comparisons between the analytical predictions and the measured performance of the control system. It is the first step in a project to achieve routine field regulation better than 10ppm. The control loop was decomposed into functional subcircuits and simulated in SPICE to determine DC, AC, and transient response. Transfer functions were extracted from SPICE, simplified, and analyzed in MATLAB. Both SPICE and MATLAB simulations were calculated for step inputs, and these results were compared to actual measurements. Magnetic field fluctuations were measured at high mass resolving power. The frequency spectrum of the fluctuations was analyzed by FFT. Difficulties encountered and implications for future work are discussed.

  19. ISTTOK upgrade towards AC and remote operation

    NASA Astrophysics Data System (ADS)

    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.

  20. Regulators as agents: modelling personality and power as evidence is brokered to support decisions on environmental risk.

    PubMed

    Davies, G J; Kendall, G; Soane, E; Li, J; Rocks, S A; Jude, S R; Pollard, S J T

    2014-01-01

    Complex regulatory decisions about risk rely on the brokering of evidence between providers and recipients, and involve personality and power relationships that influence the confidence that recipients may place in the sufficiency of evidence and, therefore, the decision outcome. We explore these relationships in an agent-based model; drawing on concepts from environmental risk science, decision psychology and computer simulation. A two-agent model that accounts for the sufficiency of evidence is applied to decisions about salt intake, animal carcass disposal and radioactive waste. A dynamic version of the model assigned personality traits to agents, to explore their receptivity to evidence. Agents with 'aggressor' personality sets were most able to imbue fellow agents with enhanced receptivity (with 'avoider' personality sets less so) and clear confidence in the sufficiency of evidence. In a dynamic version of the model, when both recipient and provider were assigned the 'aggressor' personality set, this resulted in 10 successful evidence submissions in 71 days, compared with 96 days when both agents were assigned the 'avoider' personality set. These insights suggest implications for improving the efficiency and quality of regulatory decision making by understanding the role of personality and power.

  1. Reconfigurable Resonant Regulating Rectifier With Primary Equalization for Extended Coupling- and Loading-Range in Bio-Implant Wireless Power Transfer.

    PubMed

    Li, Xing; Meng, Xiaodong; Tsui, Chi-Ying; Ki, Wing-Hung

    2015-12-01

    Wireless power transfer using reconfigurable resonant regulating (R(3)) rectification suffers from limited range in accommodating varying coupling and loading conditions. A primary-assisted regulation principle is proposed to mitigate these limitations, of which the amplitude of the rectifier input voltage on the secondary side is regulated by accordingly adjusting the voltage amplitude Veq on the primary side. A novel current-sensing method and calibration scheme track Veq on the primary side. A ramp generator simultaneously provides three clock signals for different modules. Both the primary equalizer and the R(3) rectifier are implemented as custom integrated circuits fabricated in a 0.35 μm CMOS process, with the global control implemented in FPGA. Measurements show that with the primary equalizer, the workable coupling and loading ranges are extended by 250% at 120 mW load and 300% at 1.2 cm coil distance compared to the same system without the primary equalizer. A maximum rectifier efficiency of 92.5% and a total system efficiency of 62.4% are demonstrated.

  2. Multimode power processor

    DOEpatents

    O'Sullivan, George A.; O'Sullivan, Joseph A.

    1999-01-01

    In one embodiment, a power processor which operates in three modes: an inverter mode wherein power is delivered from a battery to an AC power grid or load; a battery charger mode wherein the battery is charged by a generator; and a parallel mode wherein the generator supplies power to the AC power grid or load in parallel with the battery. In the parallel mode, the system adapts to arbitrary non-linear loads. The power processor may operate on a per-phase basis wherein the load may be synthetically transferred from one phase to another by way of a bumpless transfer which causes no interruption of power to the load when transferring energy sources. Voltage transients and frequency transients delivered to the load when switching between the generator and battery sources are minimized, thereby providing an uninterruptible power supply. The power processor may be used as part of a hybrid electrical power source system which may contain, in one embodiment, a photovoltaic array, diesel engine, and battery power sources.

  3. Multimode power processor

    DOEpatents

    O'Sullivan, G.A.; O'Sullivan, J.A.

    1999-07-27

    In one embodiment, a power processor which operates in three modes: an inverter mode wherein power is delivered from a battery to an AC power grid or load; a battery charger mode wherein the battery is charged by a generator; and a parallel mode wherein the generator supplies power to the AC power grid or load in parallel with the battery. In the parallel mode, the system adapts to arbitrary non-linear loads. The power processor may operate on a per-phase basis wherein the load may be synthetically transferred from one phase to another by way of a bumpless transfer which causes no interruption of power to the load when transferring energy sources. Voltage transients and frequency transients delivered to the load when switching between the generator and battery sources are minimized, thereby providing an uninterruptible power supply. The power processor may be used as part of a hybrid electrical power source system which may contain, in one embodiment, a photovoltaic array, diesel engine, and battery power sources. 31 figs.

  4. AC motor controller with 180 degree conductive switches

    NASA Technical Reports Server (NTRS)

    Oximberg, Carol A. (Inventor)

    1995-01-01

    An ac motor controller is operated by a modified time-switching scheme where the switches of the inverter are on for electrical-phase-and-rotation intervals of 180.degree. as opposed to the conventional 120.degree.. The motor is provided with three-phase drive windings, a power inverter for power supplied from a dc power source consisting of six switches, and a motor controller which controls the current controlled switches in voltage-fed mode. During full power, each switch is gated continuously for three successive intervals of 60.degree. and modulated for only one of said intervals. Thus, during each 60.degree. interval, the two switches with like signs are on continuously and the switch with the opposite sign is modulated.

  5. ac electroosmosis in rectangular microchannels.

    PubMed

    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.

  6. ACS PSF Variations with Temperatures

    NASA Astrophysics Data System (ADS)

    Sahu, Kailash C.; Lallo, Matt; Makidon, Russ

    2007-09-01

    We have used the HST ACS/WFC observations of a Galactic bulge field taken over a continuous interval of 7 days (Prop 9750) to investigate the possible dependence of the ACS focus with the external temperatures. This dataset allows us to investigate possible focus variations over timescales of a few hours to a few days. The engineering data related to the external temperatures for this duration show that the maximum temperature change occurred over the first 1.5 days. Among all the different temperatures recorded, the truss diametric differential and the truss axial temperatures are the only two temperatures which have the same timescale of variation as the PSFwidth variations. The PSF-widths also strongly correlate with these two temperatures during this time interval. We empirically fit the PSF-width variations with these 2 temperature sensor values. This suggests that the focus has a similar dependence, and we recommend that this finding be followed up with the determination of actual focus values to check if the focus values indeed have the same correlation. If so, the temperature data can be useful in estimating the focus values, which can then be used to predict the PSFs to a first order.

  7. ac electroosmosis in rectangular microchannels

    NASA Astrophysics Data System (ADS)

    Campisi, Michele; Accoto, Dino; Dario, Paolo

    2005-11-01

    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-Hückel 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.

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

    PubMed Central

    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. RHIC spin flipper AC dipole controller

    SciTech Connect

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

    2011-03-28

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

  10. Numerical simulations of electromagnetic behavior and AC loss in rectangular bulk superconductor with an elliptical flaw under AC magnetic fields

    NASA Astrophysics Data System (ADS)

    Xia, Jing; Zhou, Youhe

    2015-07-01

    This paper presents a finite element model based on the H-formulation to solve the electromagnetic behavior and AC loss in rectangular bulk superconductor with an elliptical flaw in AC external field condition. Both the interior flaw and the edge flaw are considered. A modified E-J power law which is valid for an arbitrary current density range is adopted in order to predict the strong local enhancement of the current density in the vicinity of the flaw tip. The results for the usual E-J power law are calculated for comparison as well. The simulation results show that the existence of the flaw significantly blocks the flow of the induced current and forces the current to redistribute around it. Meanwhile, the strong local enhancement of the current density is observed in the vicinity of the flaw tip. Furthermore, the influences of the size and position of the flaw on the local enhancement of the current density in the vicinity of the flaw tip are investigated. In addition, it is found that the influence of the flaw on the AC loss of the sample is slight for both cases of the interior flaw and the edge flaw.

  11. Low-to-Medium Power Single Chip Digital Controlled DC-DC Regulator for Point-of-Load Applications

    NASA Technical Reports Server (NTRS)

    Adell, Philippe C. (Inventor); Bakkaloglu, Bertan (Inventor); Vermeire, Bert (Inventor); Liu, Tao (Inventor)

    2015-01-01

    A DC-DC converter for generating a DC output voltage includes: a digitally controlled pulse width modulator (DPWM) for controlling a switching power stage to supply a varying voltage to an inductor; and a digital voltage feedback circuit for controlling the DPWM in accordance with a feedback voltage corresponding to the DC output voltage, the digital voltage feedback circuit including: a first voltage controlled oscillator for converting the feedback voltage into a first frequency signal and to supply the first frequency signal to a first frequency discriminator; a second voltage controlled oscillator for converting a reference voltage into a second frequency signal and to supply the second frequency signal to a second frequency discriminator; a digital comparator for comparing digital outputs of the first and second frequency discriminators and for outputting a digital feedback signal; and a controller for controlling the DPWM in accordance with the digital feedback signal.

  12. Distributed Control of Inverter-Based Lossy Microgrids for Power Sharing and Frequency Regulation Under Voltage Constraints

    SciTech Connect

    Chang, Chin-Yao; Zhang, Wei

    2016-01-19

    This paper presents a new distributed control framework to coordinate inverter-interfaced distributed energy resources (DERs) in island microgrids. We show that under bounded load uncertainties, the proposed control method can steer the microgrid to a desired steady state with synchronized inverter frequency across the network and proportional sharing of both active and reactive powers among the inverters. We also show that such convergence can be achieved while respecting constraints on voltage magnitude and branch angle differences. The controller is robust under various contingency scenarios, including loss of communication links and failures of DERs. The proposed controller is applicable to lossy mesh microgrids with heterogeneous R/X distribution lines and reasonable parameter variations. Simulations based on various microgrid operation scenarios are also provided to show the effectiveness of the proposed control method.

  13. Long-range response in ac electricity grids.

    PubMed

    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.

  14. Long-range response in ac electricity grids

    NASA Astrophysics Data System (ADS)

    Jung, Daniel; Kettemann, Stefan

    2016-07-01

    Local changes in the topology of electricity grids can cause overloads far away from the disturbance [D. Witthaut and M. Timme, Eur. Phys. J. B 86, 377 (2013), 10.1140/epjb/e2013-40469-4], making the prediction of the robustness against changes in the topology—for example, caused by power outages or grid extensions—a challenging task. The impact of single-line additions on the long-range response of dc electricity grids has recently been studied [D. Labavić, R. Suciu, H. Meyer-Ortmanns, and S. Kettemann, Eur. Phys. J.: Spec. Top. 223, 2517 (2014), 10.1140/epjst/e2014-02273-0]. By solving the real part of the static ac load flow equations, we conduct a similar investigation for ac grids. In a regular two-dimensional grid graph with cyclic boundary conditions, we find a power law decay for the change of power flow as a function of distance to the disturbance over a wide range of distances. The power exponent increases and saturates for large system sizes. By applying the same analysis to the German transmission grid topology, we show that also in real-world topologies a long-ranged response can be found.

  15. Dynamic performance of a disk-type magnetorheological fluid damper under AC excitation

    NASA Astrophysics Data System (ADS)

    Zhu, Changsheng

    2005-02-01

    It is shown that the dynamic behaviour of a disk-type magnetorheological (MR) fluid damper developed on shear mode for rotational machinery can be controlled by application of an external DC magnetic field produced by a low voltage electromagnetic coil and that the disk-type MR fluid damper can effectively attenuate the rotor vibration. In this paper, the dynamic behaviour of the disk-type MR fluid damper for attenuating rotor vibration under AC sinusoidal magnetic field is experimentally studied on a flexible rotor. It is shown that as the frequency of applied AC sinusoidal magnetic field increases, the capability of the disk-type MR fluid damper to attenuate rotor vibration significantly reduces. There is a maximum frequency of AC sinusoidal magnetic field for a given applied magnetic field strength to realize the MR effect. When the frequency of AC sinusoidal magnetic field is over the maximum frequency, the MR activity almost completely disappears and the dynamic behaviour of the disk-type MR fluid dampers under a high frequency AC magnetic field is the same as that without magnetic field. For a given sinusoidal magnetic field frequency, there is also a minimum AC sinusoidal magnetic field to active the MR effect. In the rotor vibration control of view, it is not necessary to use the AC power supply for disk-type MR fluid dampers.

  16. Achieving High Performance in AC-Field Driven Organic Light Sources

    PubMed Central

    Xu, Junwei; Carroll, David L.; Smith, Gregory M.; Dun, Chaochao; Cui, Yue

    2016-01-01

    Charge balance in organic light emitting structures is essential to simultaneously achieving high brightness and high efficiency. In DC-driven organic light emitting devices (OLEDs), this is relatively straight forward. However, in the newly emerging, capacitive, field-activated AC-driven organic devices, charge balance can be a challenge. In this work we introduce the concept of gating the compensation charge in AC-driven organic devices and demonstrate that this can result in exceptional increases in device performance. To do this we replace the insulator layer in a typical field-activated organic light emitting device with a nanostructured, wide band gap semiconductor layer. This layer acts as a gate between the emitter layer and the voltage contact. Time resolved device characterization shows that, at high-frequencies (over 40 kHz), the semiconductor layer allows for charge accumulation in the forward bias, light generating part of the AC cycle and charge compensation in the negative, quiescent part of the AC cycle. Such gated AC organic devices can achieve a non-output coupled luminance of 25,900 cd/m2 with power efficiencies that exceed both the insulator-based AC devices and OLEDs using the same emitters. This work clearly demonstrates that by realizing balanced management of charge, AC-driven organic light emitting devices may well be able to rival today’s OLEDs in performance. PMID:27063414

  17. Achieving High Performance in AC-Field Driven Organic Light Sources

    NASA Astrophysics Data System (ADS)

    Xu, Junwei; Carroll, David L.; Smith, Gregory M.; Dun, Chaochao; Cui, Yue

    2016-04-01

    Charge balance in organic light emitting structures is essential to simultaneously achieving high brightness and high efficiency. In DC-driven organic light emitting devices (OLEDs), this is relatively straight forward. However, in the newly emerging, capacitive, field-activated AC-driven organic devices, charge balance can be a challenge. In this work we introduce the concept of gating the compensation charge in AC-driven organic devices and demonstrate that this can result in exceptional increases in device performance. To do this we replace the insulator layer in a typical field-activated organic light emitting device with a nanostructured, wide band gap semiconductor layer. This layer acts as a gate between the emitter layer and the voltage contact. Time resolved device characterization shows that, at high-frequencies (over 40 kHz), the semiconductor layer allows for charge accumulation in the forward bias, light generating part of the AC cycle and charge compensation in the negative, quiescent part of the AC cycle. Such gated AC organic devices can achieve a non-output coupled luminance of 25,900 cd/m2 with power efficiencies that exceed both the insulator-based AC devices and OLEDs using the same emitters. This work clearly demonstrates that by realizing balanced management of charge, AC-driven organic light emitting devices may well be able to rival today’s OLEDs in performance.

  18. A comparative study of electric power distribution systems for spacecraft

    NASA Technical Reports Server (NTRS)

    Stuart, Thomas A.; King, Roger J.

    1990-01-01

    The electric power distribution systems for spacecraft are compared concentrating on two interrelated issues: the choice between dc and high frequency ac, and the converter/inverter topology to be used at the power source. The relative merits of dc and ac distribution are discussed. Specific converter and inverter topologies are identified and analyzed in detail for the purpose of detailed comparison. Finally, specific topologies are recommended for use in dc and ac systems.

  19. Design of Distributed Controllers Seeking Optimal Power Flow Solutions Under Communication Constraints

    SciTech Connect

    Dall'Anese, Emiliano; Simonetto, Andrea; Dhople, Sairaj

    2016-12-29

    This paper focuses on power distribution networks featuring inverter-interfaced distributed energy resources (DERs), and develops feedback controllers that drive the DER output powers to solutions of time-varying AC optimal power flow (OPF) problems. Control synthesis is grounded on primal-dual-type methods for regularized Lagrangian functions, as well as linear approximations of the AC power-flow equations. Convergence and OPF-solution-tracking capabilities are established while acknowledging: i) communication-packet losses, and ii) partial updates of control signals. The latter case is particularly relevant since it enables asynchronous operation of the controllers where DER setpoints are updated at a fast time scale based on local voltage measurements, and information on the network state is utilized if and when available, based on communication constraints. As an application, the paper considers distribution systems with high photovoltaic integration, and demonstrates that the proposed framework provides fast voltage-regulation capabilities, while enabling the near real-time pursuit of solutions of AC OPF problems.

  20. Design of Distributed Controllers Seeking Optimal Power Flow Solutions under Communication Constraints: Preprint

    SciTech Connect

    Dall'Anese, Emiliano; Simonetto, Andrea; Dhople, Sairaj

    2016-12-01

    This paper focuses on power distribution networks featuring inverter-interfaced distributed energy resources (DERs), and develops feedback controllers that drive the DER output powers to solutions of time-varying AC optimal power flow (OPF) problems. Control synthesis is grounded on primal-dual-type methods for regularized Lagrangian functions, as well as linear approximations of the AC power-flow equations. Convergence and OPF-solution-tracking capabilities are established while acknowledging: i) communication-packet losses, and ii) partial updates of control signals. The latter case is particularly relevant since it enables asynchronous operation of the controllers where DER setpoints are updated at a fast time scale based on local voltage measurements, and information on the network state is utilized if and when available, based on communication constraints. As an application, the paper considers distribution systems with high photovoltaic integration, and demonstrates that the proposed framework provides fast voltage-regulation capabilities, while enabling the near real-time pursuit of solutions of AC OPF problems.

  1. Mathematical model for the dc-ac inverter for the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Berry, Frederick C.

    1987-01-01

    The reader is informed of what was done for the mathematical modeling of the dc-ac inverter for the Space Shuttle. The mathematical modeling of the dc-ac inverter is an essential element in the modeling of the electrical power distribution system of the Space Shuttle. The electrical power distribution system which is present on the Space Shuttle is made up to 3 strings each having a fuel cell which provides dc to those systems which require dc, and the inverters which convert the dc to ac for those elements which require ac. The inverters are units which are 2 wire structures for the main dc inputs and 2 wire structures for the ac output. When 3 are connected together a 4 wire wye connection results on the ac side. The method of modeling is performed by using a Least Squares curve fitting method. A computer program is presented for implementation of the model along with graphs and tables to demonstrate the accuracy of the model.

  2. Construction and evaluation of photovoltaic power generation and power storage system using SiC field-effect transistor inverter

    SciTech Connect

    Oku, Takeo Matsumoto, Taisuke; Ohishi, Yuya; Hiramatsu, Koichi; Yasuda, Masashi; Shimono, Akio; Takeda, Yoshikazu; Murozono, Mikio

    2016-02-01

    A power storage system using spherical silicon (Si) solar cells, maximum power point tracking charge controller, lithium-ion battery and a direct current-alternating current (DC-AC) inverter was constructed. Performance evaluation of the DC-AC inverter was carried out, and the DC-AC conversion efficiencies of the SiC field-effect transistor (FET) inverter was improved compared with those of the ordinary Si-FET based inverter.

  3. AC Impedance Studies on Metal/Nanoporous Silicon/ p-Silicon Structures

    NASA Astrophysics Data System (ADS)

    Mabrook, M. F.; Ray, A. K.

    2017-04-01

    Alternating current (AC) impedance measurements have been performed on 10- to 15- μm thick porous silicon layers on a (100) p-type silicon ( p(+)Si) substrate with the aluminium (Al) top electrode in a sandwich configuration in the range of 20 Hz-1 MHz and in the temperature ranging between 152 K and 292 K. The ac conductivity σ ac was found to increase with frequency f according to the universal power law: σ_{{ac}} = Afs where the exponent s is a frequency and temperature-dependent quantity. A hopping process is found to be dominant at low temperatures and high frequencies, while a thermally activated free band process is responsible for conduction at higher temperatures. Capacitance is found to decrease with frequency but increase with temperature. Frequency dependence of the loss tangent is observed with a temperature-dependent minimum value.

  4. AC Impedance Studies on Metal/Nanoporous Silicon/p-Silicon Structures

    NASA Astrophysics Data System (ADS)

    Mabrook, M. F.; Ray, A. K.

    2016-11-01

    Alternating current (AC) impedance measurements have been performed on 10- to 15-μm thick porous silicon layers on a (100) p-type silicon (p(+)Si) substrate with the aluminium (Al) top electrode in a sandwich configuration in the range of 20 Hz-1 MHz and in the temperature ranging between 152 K and 292 K. The ac conductivity σ ac was found to increase with frequency f according to the universal power law: σ_{ac} = Afs where the exponent s is a frequency and temperature-dependent quantity. A hopping process is found to be dominant at low temperatures and high frequencies, while a thermally activated free band process is responsible for conduction at higher temperatures. Capacitance is found to decrease with frequency but increase with temperature. Frequency dependence of the loss tangent is observed with a temperature-dependent minimum value.

  5. Magnetic Amplifier-Based Power-Flow Controller

    DOE PAGES

    Dimitrovski, Aleksandar; Li, Zhi; Ozpineci, Burak

    2015-02-05

    The concept of the magnetic amplifier, a common electromagnetic device in electronic applications in the past, has seldom been used in power systems. In this paper, we introduce the magnetic amplifier-based power-flow controller (MAPFC), an innovative low-cost device that adopts the idea of the magnetic amplifier for power-flow control applications. The uniqueness of MAPFC is in the use of the magnetization of the ferromagnetic core, shared by an ac and a dc winding, as the medium to control the ac winding reactance inserted in series with the transmission line to be controlled. Large power flow in the line can bemore » regulated by the small dc input to the dc winding. Moreover, a project on the R&D of an MAPFC has been funded by the U.S. Department of Energy (DOE) and conducted by the Oak Ridge National Laboratory (ORNL), the University of Tennessee-Knoxville, and Waukesha Electric Systems, Inc. since early 2012. Findings from the project are presented along with some results obtained in a laboratory environment.« less

  6. Magnetic Amplifier-Based Power-Flow Controller

    SciTech Connect

    Dimitrovski, Aleksandar; Li, Zhi; Ozpineci, Burak

    2015-02-05

    The concept of the magnetic amplifier, a common electromagnetic device in electronic applications in the past, has seldom been used in power systems. In this paper, we introduce the magnetic amplifier-based power-flow controller (MAPFC), an innovative low-cost device that adopts the idea of the magnetic amplifier for power-flow control applications. The uniqueness of MAPFC is in the use of the magnetization of the ferromagnetic core, shared by an ac and a dc winding, as the medium to control the ac winding reactance inserted in series with the transmission line to be controlled. Large power flow in the line can be regulated by the small dc input to the dc winding. Moreover, a project on the R&D of an MAPFC has been funded by the U.S. Department of Energy (DOE) and conducted by the Oak Ridge National Laboratory (ORNL), the University of Tennessee-Knoxville, and Waukesha Electric Systems, Inc. since early 2012. Findings from the project are presented along with some results obtained in a laboratory environment.

  7. Design note about a 75 KVA quiet power distribution system

    SciTech Connect

    Visser, A.T.

    1984-04-05

    This note describes a 75KVA quiet power distribution system for X 653 in neutrino Lab D. It is fed from the regular AC distribution which exists in the building and it has no standby power. Its purpose is to remove electrical disturbances which are present on the regular AC distribution.

  8. xopAC-triggered Immunity against Xanthomonas Depends on Arabidopsis Receptor-Like Cytoplasmic Kinase Genes PBL2 and RIPK

    PubMed Central

    Guy, Endrick; Lautier, Martine; Chabannes, Matthieu; Roux, Brice; Lauber, Emmanuelle; Arlat, Matthieu; Noël, Laurent D.

    2013-01-01

    Xanthomonas campestris pv. campestris (Xcc) colonizes the vascular system of Brassicaceae and ultimately causes black rot. In susceptible Arabidopsis plants, XopAC type III effector inhibits by uridylylation positive regulators of the PAMP-triggered immunity such as the receptor-like cytoplasmic kinases (RLCK) BIK1 and PBL1. In the resistant ecotype Col-0, xopAC is a major avirulence gene of Xcc. In this study, we show that both the RLCK interaction domain and the uridylyl transferase domain of XopAC are required for avirulence. Furthermore, xopAC can also confer avirulence to both the vascular pathogen Ralstonia solanacearum and the mesophyll-colonizing pathogen Pseudomonas syringae indicating that xopAC-specified effector-triggered immunity is not specific to the vascular system. In planta, XopAC-YFP fusions are localized at the plasma membrane suggesting that XopAC might interact with membrane-localized proteins. Eight RLCK of subfamily VII predicted to be localized at the plasma membrane and interacting with XopAC in yeast two-hybrid assays have been isolated. Within this subfamily, PBL2 and RIPK RLCK genes but not BIK1 are important for xopAC-specified effector-triggered immunity and Arabidopsis resistance to Xcc. PMID:23951354

  9. AC Coupled Interconnect for Low Power Spaceborne Electronics

    DTIC Science & Technology

    2012-01-18

    architecture ............................................49 Figure 77 In-flight module showing motherboard (red) and ASIM (green... motherboard (the red board on the floor of the module) and the ASIM (the green board in the center): Figure 77 In-flight module showing... motherboard (red) and ASIM (green) The motherboard contains the Virtex II FPGA (which is underneath the ASIM in the picture.). The cover of the

  10. Truthful Mechanisms for Combinatorial AC Electric Power Allocation

    DTIC Science & Technology

    2014-05-01

    unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 In mechanism design setting...axis and c2 on the imaginary axis. This table can be filled-up by standard dynamic programming; we de- note such a program by Multi-2DKP-Exact[·]. For...REFERENCES [1] National Electrical Code (NEC) NFPA 70-2005. [2] P. Briest, P. Krysta, and B. Vocking. Approximation techniques for utilitarian mechanism

  11. Auxiliary power controls on the Nelson River HVDC scheme

    SciTech Connect

    Chand, J. )

    1992-02-01

    This paper describes the auxiliary power controls on the Nelson River HVDC scheme. It shows how the fast control feature of the HVDC link can be utilized to enhance the operation of an integrated ac/dc power system.

  12. Delocalization of disturbances and the stability of ac electricity grids.

    PubMed

    Kettemann, Stefan

    2016-12-01

    In order to study how local disturbances affect the ac grid stability, we start from nonlinear power balance equations and map them to complex linear wave equations. Having obtained stationary solutions with phases φ_{i} at generator and consumer nodes i, we next study the dynamics of deviations. Starting with an initially localized perturbation, it is found to spread in a periodic grid diffusively throughout the grid. We find the parametric dependence of diffusion constant D. We apply the same solution strategy to general grid topologies and analyze their stability against local perturbations. The perturbation remains either localized or becomes delocalized, depending on grid topology, power capacity, and distribution of consumers and generator power P_{i}. Delocalization is found to increase the lifetime of perturbations and thereby their influence on grid stability, whereas localization results in an exponentially fast decay of perturbations at all grid sites. These results may therefore lead to new strategies to control the stability of electricity grids.

  13. Delocalization of disturbances and the stability of ac electricity grids

    NASA Astrophysics Data System (ADS)

    Kettemann, Stefan

    2016-12-01

    In order to study how local disturbances affect the ac grid stability, we start from nonlinear power balance equations and map them to complex linear wave equations. Having obtained stationary solutions with phases φi at generator and consumer nodes i , we next study the dynamics of deviations. Starting with an initially localized perturbation, it is found to spread in a periodic grid diffusively throughout the grid. We find the parametric dependence of diffusion constant D . We apply the same solution strategy to general grid topologies and analyze their stability against local perturbations. The perturbation remains either localized or becomes delocalized, depending on grid topology, power capacity, and distribution of consumers and generator power Pi. Delocalization is found to increase the lifetime of perturbations and thereby their influence on grid stability, whereas localization results in an exponentially fast decay of perturbations at all grid sites. These results may therefore lead to new strategies to control the stability of electricity grids.

  14. Lamin A/C sustains PcG protein architecture, maintaining transcriptional repression at target genes

    PubMed Central

    Cesarini, Elisa; Mozzetta, Chiara; Marullo, Fabrizia; Gregoretti, Francesco; Gargiulo, Annagiusi; Columbaro, Marta; Cortesi, Alice; Antonelli, Laura; Di Pelino, Simona; Squarzoni, Stefano; Palacios, Daniela; Zippo, Alessio; Bodega, Beatrice; Oliva, Gennaro

    2015-01-01

    Beyond its role in providing structure to the nuclear envelope, lamin A/C is involved in transcriptional regulation. However, its cross talk with epigenetic factors—and how this cross talk influences physiological processes—is still unexplored. Key epigenetic regulators of development and differentiation are the Polycomb group (PcG) of proteins, organized in the nucleus as microscopically visible foci. Here, we show that lamin A/C is evolutionarily required for correct PcG protein nuclear compartmentalization. Confocal microscopy supported by new algorithms for image analysis reveals that lamin A/C knock-down leads to PcG protein foci disassembly and PcG protein dispersion. This causes detachment from chromatin and defects in PcG protein–mediated higher-order structures, thereby leading to impaired PcG protein repressive functions. Using myogenic differentiation as a model, we found that reduced levels of lamin A/C at the onset of differentiation led to an anticipation of the myogenic program because of an alteration of PcG protein–mediated transcriptional repression. Collectively, our results indicate that lamin A/C can modulate transcription through the regulation of PcG protein epigenetic factors. PMID:26553927

  15. Lamin A/C sustains PcG protein architecture, maintaining transcriptional repression at target genes.

    PubMed

    Cesarini, Elisa; Mozzetta, Chiara; Marullo, Fabrizia; Gregoretti, Francesco; Gargiulo, Annagiusi; Columbaro, Marta; Cortesi, Alice; Antonelli, Laura; Di Pelino, Simona; Squarzoni, Stefano; Palacios, Daniela; Zippo, Alessio; Bodega, Beatrice; Oliva, Gennaro; Lanzuolo, Chiara

    2015-11-09

    Beyond its role in providing structure to the nuclear envelope, lamin A/C is involved in transcriptional regulation. However, its cross talk with epigenetic factors--and how this cross talk influences physiological processes--is still unexplored. Key epigenetic regulators of development and differentiation are the Polycomb group (PcG) of proteins, organized in the nucleus as microscopically visible foci. Here, we show that lamin A/C is evolutionarily required for correct PcG protein nuclear compartmentalization. Confocal microscopy supported by new algorithms for image analysis reveals that lamin A/C knock-down leads to PcG protein foci disassembly and PcG protein dispersion. This causes detachment from chromatin and defects in PcG protein-mediated higher-order structures, thereby leading to impaired PcG protein repressive functions. Using myogenic differentiation as a model, we found that reduced levels of lamin A/C at the onset of differentiation led to an anticipation of the myogenic program because of an alteration of PcG protein-mediated transcriptional repression. Collectively, our results indicate that lamin A/C can modulate transcription through the regulation of PcG protein epigenetic factors.

  16. Modeling AC ripple currents in HTS coated conductors by integral equations

    NASA Astrophysics Data System (ADS)

    Grilli, Francesco; Xu, Zhihan

    2016-12-01

    In several HTS applications, the superconducting tapes experience the simultaneous presence of DC and AC excitations. For example in high-current DC cables, where the transport current is not perfectly constant, but it exhibits some ripples at different frequencies introduced by the rectification process (AC-DC conversion). These ripples give rise to dissipation, whose magnitude and possible influence on the device's cooling requirements need to be evaluated. Here we report a study of the AC losses in a HTS coated conductor subjected to DC currents and AC ripples simultaneously. The modeling approach is based on an integral equation method for thin superconductors: the superconducting tape is modeled as a 1-D object with a non-linear resistivity, which includes the dependence of the critical current density Jc on the magnetic field. The model, implemented in a commercial finite-element program, runs very fast (the simulation of one AC cycle typically takes a few seconds on standard desktop workstation): this allows simulating a large number of cycles and estimating when the AC ripple losses stabilize to a constant value. The model is used to study the influence of the flux creep power index n on the stabilization speed and on the AC loss values, as well as the effect of using a field-dependent Jc instead of a constant one. The simulations confirm that the dissipation level should not be a practical concern in HTS DC cables. At the same time, however, they reveal a strong dependence of the results upon the power index n and the form of Jc , which spurs the question whether the power-law is the most suitable description of the superconductor's electrical behavior for this kind of analysis.

  17. Photovoltaic (PV) Power Systems for Enhancing Energy Security

    DTIC Science & Technology

    2012-05-24

    Energy and Environment Technology Transition – Supporting DoD Readiness, Sustainability, and the Warfighter Photovoltaic (PV) Power Systems for...to 00-00-2012 4. TITLE AND SUBTITLE Photovoltaic (PV) Power Systems for Enhancing Energy Security 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c...use of 235W solar panels Note [2] System AC Rating based upon typical .77 conversion factor from DC power to AC power ConsiderationNo. PV LAYOUT OPTION

  18. Frequency-controlled voltage regulator

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1980-01-01

    Converting input ac to higher frequency reduce size and weight and makes possible unique kind of regulation. Since conversion frequency is above range of human hearing, supply generated on audible noise. It also exploits highfrequency conversion features to regulate its output voltage in novel way. Circuit is inherently short-circuit proof.

  19. Active AC/DC control for wideband piezoelectric energy harvesting

    NASA Astrophysics Data System (ADS)

    Morel, A.; Grézaud, R.; Pillonnet, G.; Gasnier, P.; Despesse, G.; Badel, A.

    2016-11-01

    This paper proposes a simple interface circuit enabling resonant frequency tuning of highly coupled piezoelectric harvesters. This work relies on an active AC/DC architecture that introduces a tunable short-circuit sequence in order to control the phase between the piezoelectric current and voltage, allowing the emulation of a capacitive load. It is notably shown that this short-circuit time increases the harvested power when the piezoelectric operates outside of resonance. Measurements on a piezoelectric harvester exhibiting a large global coupling coefficient (k2 = 15.3%) have been realized and have proven the efficiency and potential of this technique.

  20. Measurement of AC electrical characteristics of SSC superconducting dipole magnets

    SciTech Connect

    Smedley, K M; Shafer, R E

    1992-01-01

    Experiments were conducted to measure the AC electrical characteristics of SSC superconducting dipole magnets over the frequency range of 0.1 Hz to 10 kHz. A magnet equivalent circuit representing the magnet DC inductance, eddy current losses, coil-to-ground and turn-to-turn capacitance, was synthesized from the experimental data. This magnet equivalent circuit can be used to predict the current ripple distribution along the superconducting magnet string and can provide dynamic information for the design of the collider current regulation loop.