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Sample records for ac adjustable speed

  1. ANALYSIS OF EFFECTS OF VECTOR CONTROL ON TOTAL CURRENT HARMONIC DISTORTION OF ADJUSTABLE SPEED AC DRIVE

    KARTIK TAMVADA

    2012-04-01

    Full Text Available Adjustable speed drive (ASD is becoming a significant load component for power distribution. It involves the use of an Induction motor (IM. This paper involves modeling and control of an Induction motor andinvestigates its effects on the total current harmonic distortion of the adjustable speed ac drives. The simulation was carried out with the aid of the Simulink toolbox available in Matlab. It is seen that with Vector control the THDi of the drive reduces considerably.

  2. ANALYSIS OF EFFECTS OF VECTOR CONTROL ON TOTAL CURRENT HARMONIC DISTORTION OF ADJUSTABLE SPEED AC DRIVE

    KARTIK TAMVADA; R.KAMESWARA RAO

    2012-01-01

    Adjustable speed drive (ASD) is becoming a significant load component for power distribution. It involves the use of an Induction motor (IM). This paper involves modeling and control of an Induction motor andinvestigates its effects on the total current harmonic distortion of the adjustable speed ac drives. The simulation was carried out with the aid of the Simulink toolbox available in Matlab. It is seen that with Vector control the THDi of the drive reduces considerably.

  3. High-speed AC motors

    Jokinen, T.; Arkkio, A. [Helsinki University of Technology Laboratory of Electromechanics, Otaniemi (Finland)

    1997-12-31

    The paper deals with various types of highspeed electric motors, and their limiting powers. Standard machines with laminated rotors can be utilised if the speed is moderate. The solid rotor construction makes it possible to reach higher power and speed levels than those of laminated rotors. The development work on high-speed motors done at Helsinki University of Technology is presented, too. (orig.) 12 refs.

  4. Speed of adjustment: Evidence from Borsa Istanbul

    Emrah Arioglu

    2014-06-01

    Full Text Available In this study, we investigate the speed of adjustment for leverage ratios of firms listed on Borsa Istanbul, in order to investigate the prediction of the trade-off theory, regarding capital structure rebalancing. For this purpose, we estimate the speed of adjustment by using Generalized Method of Moments system estimation technique. The results of this estimation suggest the speed of adjustment as approximately 29%. This significant speed of adjustment is consistent with the prediction of trade-off theory, which suggests that firms follow target capital structures and when the firms' leverage ratios deviate from these targets; they make financial decisions with the goal of closing the gap between the previous year's leverage and target leverage of the current period.

  5. Adjustable Speed Drives - Future Challenges and Applications

    Blaabjerg, Frede; Thoegersen, Paul

    2004-01-01

    The main trends within Adjustable Drives in industrial and appliance applications for the next decade are discussed based on the newest developments seen on the market and a few historical trends. Different drive configurations are presented and the general demands to adjustable speed drives are...... specified. Further on power architectures and motor types are discussed in a short term and long-term view. Possible drivers of the future development are identified, and the concept of an ?Electronic Motor? is discussed. A number of applications are presented where variable speed is attractive....

  6. Adjustable Speed Drives and Power Quality

    Davari, Pooya; Yang, Yongheng; Zare, Firuz;

    2016-01-01

    This paper provides an overview and proposes cost-effective and efficient opportunities in improving power quality in Adjustable Speed Drive (ASD) systems. In particular, an Electronic Inductor (EI) technique has been used in single drives to overcome the existing challenges in conventional...

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

    Rakan Kh Antar

    2013-05-01

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

  8. Output filters for AC adjustable speed drives

    Blaabjerg, Frede; Hanigovszki, Norbert; Landkildehus, Jorn, Jorn

    2007-01-01

    due to bearing currents, acoustic switching noise. Depending on the specific application, the mitigation of some of these effects (or all) might be necessary. The common solution for mitigating the secondary effects at the output of PWM-VSI is the use of output filters [3],[5],[6]. Several types...... of output filters are used and this paper presents an overview of the various output filter solutions typically employed in industrial applications. The paper does not propose any new solutions and it is intended as a guide for practicing engineers and a source of information for researchers....

  9. Speed of Adjustment in Cointegrated Systems

    Fanelli, Luca; Paruolo, Paolo

    2007-01-01

    This paper considers the speed of adjustment to long-run equilibria, in the context of cointegrated Vector Autoregressive Processes (VAR). We discuss the definition of multivariate p-lives for any indicator of predictive ability, concentrating on cumulated interim multipliers which converge to impact factor for increasing forecasting horizon. Interim multipliers are related to autoregressive Granger-causality coefficients, structural or generalized cumulative impulse responses. We discuss the...

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

    Rakan Kh Antar

    2013-01-01

       This paper describes the application of ac/ac/dc and ac/dc converters to control the speed of a separately excited DC motor. Artificial neural network and PI controller are trained to select the desired values of firing angles for triggering thyristors of the ac/ac/dc and ac/dc bridge converters in order to control the speed of the dc motor at a desired value with constant and different load torques in order to obtain the best speed response. Simulation results show that the rising time fo...

  11. Adjustable speed drives: Applications and R&D needs

    Stefanovic, V.R.

    1995-09-01

    The largest opportunity for the growth of adjustable speed drives (ASDs) during the next 5-6 years is in pump, fan and compressor (PFC) applications where a constant, fixed speed operation is converted to adjustable speed in order to realize energy savings. Inverter supplied induction motors are and will continue to be predominately used in these applications. Over the long term (10-15 years), the greatest ASD growth is expected in large volume consumer applications: first in hybrid electric vehicles (EVs) and in residential heating, ventilation and air-conditioning (HVAC). Both induction and a variety of AC Permanent Magnet motors are expected to be the dominant technology in this new field. The traditional ASD applications in industries which require adjustable speed (such as machine tools, robotics, steel rolling, extruders, paper mill finishing lines, etc.) offer a relatively limited potential for above average ASD growth since most of these applications have already converted to electronic speed control. As a result, ASD growth in this sector will essentially track the growth of the corresponding industries. If realized, both short and long term ASD growth opportunities will result in significant advancements of ASD technology, which will then substantially affect all other, more fragmented, ASD applications. In fact, any single large volume ASD application will serve as a catalyst for improving ASD characteristics in all other ASD applications with the same voltage rating. ASD cost and reliability (defined in the context of application compatibility) are the two most important factors which will determine whether the ASD growth opportunities are realized. Conversely, any technological improvement which carries a cost increase will be restricted to niche applications, at best. Consequently, future R & D efforts should be directed to secure reduction in ASD cost and improvement in ASD reliability. A specific action plan is outlined in this report.

  12. Operating Regions of Adjustable-Speed Units with Doubly Fed Machines

    Schreier, Luděk; Chomát, Miroslav; Bendl, Jiří

    2004-01-01

    Roč. 49, č. 2 (2004), s. 119-136. ISSN 0001-7043 R&D Projects: GA AV ČR IAA2057102 Keywords : AC machines * adjustable-speed systems * doubly fed machine Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  13. Speed of Adjustment to Selected Labour Market and Tax Reforms

    Annabelle Mourougane; Lukas Vogel

    2009-01-01

    This paper examines the length of economic adjustments to selected structural reforms, drawing on simulations with dynamic general equilibrium and macro-economic neo-Keynesian models. Employment adjustment costs appear to have only a limited effect on the pace of adjustment to reforms and the influence of price adjustment costs on output dynamics is found to be marginal. Accommodative monetary policy can speed up the adjustment to a new equilibrium, though to a varying degree in the different...

  14. Research on AC Variable Frequency Speed Regulation System

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

    2013-01-01

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

  15. Improved speed estimation in sensorless PM brushless AC drives

    Shen, J. X.; Zhu, Z.Q.; Howe, D.

    2002-01-01

    The application of flux-observer-based sensorless control to permanent-magnet brushless AC motor drives is described. Current methods of speed estimation are assessed, both theoretically and experimentally, and an improved method, which combines the best features of methods in which speed is derived from the differential of rotor position and from the ratio of the electromotive force to excitation flux linkage, is proposed. Its performance is verified experimentally.

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

    Klumpner, Christian; Blaabjerg, Frede

    2004-01-01

    these fraction power will be a necessary feature on a deregulated energy market. This paper presents a new topology of a power converter based on the Direct Power Conversion concept, which is able to connect to multiple grids and provide complete decoupling between without circulating power between the......Normally, a power converter has one supply port to connect to the power grid and one or multiple output ports to connect to AC loads that require variable voltage and variable frequency. As the trend on the energy market is towards deregulation, new converter topologies are needed to allow...... to minimize the overall energy cost or in case of special applications, to improve the system redundancy. Also, having a generator that can simultaneously feed fractions of its power into multiple grids which are not coupled (different voltage, frequency, displacement angle) and continuously adjust...

  17. Retrofitting adjustable speed drives for large induction motors

    Adjustable speed drives (ASDs) are used in many power plants to control process flow by varying the speed of synchronous and induction motors. In applications where the flow requirements vary significantly, ASDs reduce energy and maintenance requirements when compared with drag valves, dampers or other methods to control flow. Until recently, high horsepower ASDs were not available for induction motors. However, advances in power electronics technology have demonstrated the reliability and cost effectiveness of ASDs for large horsepower induction motors. Emphasis on reducing operation and maintenance costs and increasing the capacity factor of nuclear power plants has led some utilities to consider replacing flow control devices in systems powered by large induction motors with ASDs. ASDs provide a high degree of reliability and significant energy savings in situations where full flow operation is not needed for a substantial part of the time. This paper describes the basic adjustable speed drive technologies available for large induction motor applications, ASD operating experience and retrofitting ASDs to replace the existing GE Boiling Water Reactor recirculation flow control system

  18. IMPROVED PERFORMANCE OF AN ADJUSTABLE SPEED DRIVES DURING VOLTAGE SAG CONDITION

    S.S.DESWAL

    2010-06-01

    Full Text Available Voltage sags normally do not cause equipment damage but can easily disrupt the operation of sensitive loads such as electronic Adjustable Speed Drives (ASD’s. Voltage sags cause a momentary decrease in DC-link voltage triggering an under voltage trip leading to nuisance tripping of adjustable speed drives (ASD’s employed in continuous-process industries which contributes to loss in revenue. A practical ride-through scheme for an adjustable speed drives based on supercapacitor during voltage sag has been presented in this paper. The supercapacitor maintains the ASD dc bus voltage under voltage sag condition. Energy storage module is connected to support the DC-link voltage during power system faults. The performance of ASD’s under normal and power system faults is first simulated in MATLab Simulink and then experimentally verified. The Data AcQuisition boards (DAQ of National Instruments along with LabVIEW software have been used torecord the observed waveforms.

  19. Capacitive iris to adjust coupling factor between waveguide and ACS linac in J-PARC

    The beam energy of the Japan Proton Accelerator Research Complex (J-PARC) linac has been increased from 181 to 400 MeV by installing Annular-ring Coupled Structure (ACS) cavities in the maintenance period of 2013. Some of the ACS cavities require the correction of the coupling factor between waveguide and the cavity. To adjust the coupling factor, a capacitive iris in the rectangular waveguide was designed. And then, the rectangular waveguide with the capacitive iris was manufactured and installed to one of the ACS cavities. The capacitive iris corrected the coupling factor to the designed value and performed well under high-power operation. (author)

  20. Empirical Evidence of Target Leverage, Adjustment Costs and Adjustment Speed of Non-Financial Firms in Selected African Countries

    Oyebola Fatima Etudaiye-Muhtar; Rubi Ahmad

    2015-01-01

    The issue of target leverage for corporate firms in developing countries has received little attention in extant literature, especially countries in Africa. Given the imperfection that exists in African financial markets that may limit firms access to external capital, this study investigates dynamic adjustment towards a target debt ratio. In addition, the study used a dynamic panel data estimation technique to determine adjustment costs and speed of adjustment in non-financial firms in selec...

  1. AC-DC integrated load flow calculation for variable speed offshore wind farms

    Zhao, Menghua; Chen, Zhe; Blaabjerg, Frede

    2005-01-01

    This paper proposes a sequential AC-DC integrated load flow algorithm for variable speed offshore wind farms. In this algorithm, the variable frequency and the control strategy of variable speed wind turbine systems are considered. In addition, the losses of wind turbine systems and the losses of...... converters are also integrated into the load flow algorithm. As a general algorithm, it can be applied to different types of wind farm configurations, and the load flow is related to the wind speed....

  2. Online speed control of a brushless AC servomotor based on artificial neural networks

    PARTAL, Sibel; Şenol, İbrahim; BAKAN, Ahmet Faruk

    2011-01-01

    In this paper, an alternative approach to speed estimation of brushless AC servomotors is presented. Speed control is realized in the following steps. First, the servomotor was mathematically modelled; the driver system was designed and speed control of the servomotor was accomplished with feedback. Next, a network structure representing the electrical and mechanical properties of the servomotor was built via Artificial Neural Network (ANN) and trained with the results of the first ...

  3. FLC based adjustable speed drives for power quality enhancement

    Sukumar Darly

    2010-01-01

    Full Text Available This study describes a new approach based on fuzzy algorithm to suppress the current harmonic contents in the output of an inverter. Inverter system using fuzzy controllers provide ride-through capability during voltage sags, reduces harmonics, improves power factor and high reliability, less electromagnetic interference noise, low common mode noise and extends output voltage range. A feasible test is implemented by building a model of three-phase impedance source inverter, which is designed and controlled on the basis of proposed considerations. It is verified from the practical point of view that these new approaches are more effective and acceptable to minimize the harmonic distortion and improves the quality of power. Due to the complex algorithm, their realization often calls for a compromise between cost and performance. The proposed optimizing strategies may be applied in variable-frequency dc-ac inverters, UPSs, and ac drives.

  4. From Periphery to Core: Economic Adjustments to High Speed Rail

    Ahlfeldt, Gabriel M.; Feddersen, Arne

    2010-01-01

    This paper presents evidence that high speed rail systems, by bringing economic agents closer together, sustainably promote economic activity within regions that enjoy an increase in accessibility. Our results on the one hand confirm expectations that have led to huge public investments into high speed rail all over the world. On the other hand, they confirm theoretical predictions arising from a consolidate body of (New) Economic Geography literature taking a positive, man-made and reproduci...

  5. Sensorless control of AC machines for low and zero speed operation without additional test signal injection

    Raute, Reiko

    2009-01-01

    This work considers the sensorless control of AC machines for the low and zero speed operation range. Two novel techniques have been developed that use the inherit nature of the inverter PWM to estimate the rotor position of the machine. The inherent back EMF and the saliency of AC machines can be utilized to identify the rotor/flux position. The zero vector current derivative (ZVCD) technique for permanent magnet synchronous machines (PMSM) utilizes both of these effects. No additional ...

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

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

  7. Minimize Adverse Motor and Adjustable Speed Drive Interactions - Motor Tip Sheet #15

    None

    2008-07-01

    Electronic adjustable speed drives (ASDs) are an extremely efficient and valuable asset to motor systems. They allow precise process control and provide energy savings within systems that do not need to continuously operate at full output.

  8. Improvement of power system stability of an adjustable-speed pumped-storage generator/motor. Denryoku keito ni okeru kahensoku yosui hatsuden dendoki no keito anteido kojo ni kansuru kenkyu

    Michigami, T. (Tokyo Electric Power Co., Inc. (Japan)); Koyanagi, K. (Toshiba Corp., Tokyo (Japan))

    1994-02-20

    Recently, adjustable-speed pumped-storage generator/motor (adjustable-speed machine) is applied to power system as AFC adjusting force. This adjustable-speed machine has no problem on its stability and AC excitation control is carried out by the cycloconverter with speedy response since its being different from the conventional fixed-speed synchronous machine that the rotor speed becomes to adjustable. In this paper, aiming at the improvement of power system stability by using said adjustable-speed machine, the basic consideration on the rotor speed and reactive power control by AC excitation of the adjustable-speed machine; theoretical examination on the analysis model for analysing the system stability; analysis simulation results using two machine-pair infinite system for obtaining the basic properties of the improvement of power system stability; verification results on the effectiveness of improvement of power system stability as well as analysis model by simulative power transmission test are described. Further, the analysis simulation results on the effectiveness of improvement of power system stability by the models with the scale of practical system are reported. 11 refs., 15 figs., 9 tabs.

  9. Hybrid pressure control concept for a speed variable AC motor pump in aerospace application

    Engelhardt, Joerg; Greissner, Carsten

    2002-01-01

    This paper describes a new pressure control strategy for AC motor driven pumps in aircraft application. Both, swash plate position and pump speed are used for controlling system pressure in a hybrid approach. The requirements for the pressure control loop and the design methods for the hybrid control circuits with a load observer are introduced. The new control concept has been implemented into an experimental set-up. The validation and evaluation of simulation results on the test rig are d...

  10. Maximum Efficiency Point Tracking for Adjustable-Speed Small Hydro Power Plant

    BORGHETTI Alberto; Di Silvestro, Mauro; Naldi, Gleb; Paolone, Mario; Alberti, Massimo

    2008-01-01

    The paper presents the general scheme and the relevant implementation of a Maximum Efficiency Point Tracking (MEPT) system for a Small Hydro Power (SHP) plant equipped with a variable-speed generator. This last consists of a Doubly Fed Induction Generator (DFIG) and a power electronic converter that independently controls both the rotor speed and the generator power factor. The MEPT is designed to be used with a propeller turbine with adjustable runner blade angle and it is coupled with the h...

  11. LC Filter Design for Wide Band Gap Device Based Adjustable Speed Drives

    Vadstrup, Casper; Wang, Xiongfei; Blaabjerg, Frede

    This paper presents a simple design procedure for LC filters used in wide band gap device based adjustable speed drives. Wide band gap devices offer fast turn-on and turn-off times, thus producing high dV/dt into the motor terminals. The high dV/dt can be harmful for the motor windings and bearings...

  12. Adjustable Speed Drive Project for Teaching a Servo Systems Course Laboratory

    Rodriguez-Resendiz, J.; Herrera-Ruiz, G.; Rivas-Araiza, E. A.

    2011-01-01

    This paper describes an adjustable speed drive for a three-phase motor, which has been implemented as a design for a servo system laboratory course in an engineering curriculum. The platform is controlled and analyzed in a LabVIEW environment and run on a PC. Theory is introduced in order to show the sensorless algorithms. These are computed by…

  13. Adjustable speed operation of a hydropower plant associated to an irrigation reservoir

    This paper deals with the issue of adjustable speed operation (ASO) of hydropower plants. The main idea of this technique is to allow the turbine speed to change in accordance with hydraulic conditions, thus improving the overall unit efficiency. General technical aspects of ASO are further discussed with special emphasis on the energy and operational benefits that may potentially result from its application. In order to assess these benefits, annual operation of a hydropower plant associated to an irrigation reservoir has been simulated under different scenarios, with both adjustable and fixed speed. Turbine operating range proved to be wider with ASO. In addition, simulation results confirm that considerable energy gains are expected to be obtained

  14. Intraday Speed of Adjustment and the Realized Variance in the Indonesia Stock Exchange

    Zaafri A Husodo

    2009-01-01

    Full Text Available We examine the intraday trading and price dynamics for frequently traded stocks at the Indonesian Stock Exchange. Using trade price, time series generated at one, two, three, five, ten, fifteen, thirty and sixty-minute intervals, we estimate the speed of adjustment and the corresponding realized variance of these series. The objective of the estimation is to infer the noise impact to the deviation of observed prices from their fundamental value. The result from the speed of adjustment estimate is consistent with the realized variance estimator. Both conclude that the 50 most frequently traded stocks in the Indonesia Stock Exchange adjust to new information within 30 minutes. At the interval, the coefficient of the speed of price adjustment is insignificantly different from zero implying negligible noise impact to the observed price. Concurrently, the realized variance starts to stabilize at 30-minute interval purporting fading impact of noise to the realized variance estimate. The evidence justifies the use of realized variance at various intervals as a reliable indicator of price discovery rate in the Indonesia Stock Exchange.

  15. Adjustable Speed Drives in the Next Decade. Future Steps in Industry and Academia

    Thøgersen, Paul; Blaabjerg, Frede

    2004-01-01

    The main trends for the next decade within the multi-disciplinarian field of adjustable speed drives are discussed, and a number of topics are especially addressed in this paper. The topics include market development over the last decade, historical development in power converter volume and weigh......, future drive demands, power converter architecture, interfacing to the grid, motor types, and control principles. Furthermore, some of the possibilities and trends related to decentral ?intelligence? and Internet connection are discussed.......The main trends for the next decade within the multi-disciplinarian field of adjustable speed drives are discussed, and a number of topics are especially addressed in this paper. The topics include market development over the last decade, historical development in power converter volume and weight...

  16. Speed-accuracy trade-off behavior: Response caution adjustment or mixing task strategies?

    van Maanen

    2015-01-01

    The speed-accuracy trade-off (SAT) effect refers to the behavioral trade-off between fast yet error-prone responses and accurate but slow responses. Multiple theories on the cognitive mechanisms behind SAT exist. One theory assumes that SAT is a consequence of strategically adjusting the amount of evidence required for overt behaviors, such as perceptual choices. Another theory hypothesizes that SAT is the consequence of mixing different task strategies. In this paper these theories are disam...

  17. Adjustable-Speed Single-Phase IM Drive with Reduced Number of Switches

    Chomát, Miroslav; Lipo, T. A.

    Chicago : IEEE Industry Applications Society IAS, 2001, s. 1-6. ISBN 0-7803-7114-3. [IEEE Industry Applications Conference - Annual Meeting /36./. Chicago (US), 30.09.2001-04.10.2001] R&D Projects: GA AV ČR IAB2057903 Grant ostatní: NSFA(US) 9820434 Keywords : adjustable-speed drive * single-phase induction machine Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  18. Adjustable-Speed Drive with Single-Phase Induction Machine for HVAC Applications

    Chomát, Miroslav; Lipo, T. A.

    Vancouver : University of British Columbia, 2001, s. 1-6. ISBN 0-7803-7069-4. [Power Electronics Specialists Conference PESC 2001 /32./. Vancouver (CA), 17.06.2001-22.06.2001] R&D Projects: GA MŠk ME 332 Grant ostatní: NSFA(US) 9820434 Keywords : adjustable-speed drive * single-phase induction machine Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

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

    Kiss, T.; Lustbader, J.

    2014-03-01

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

  20. Comparison between AC and MFDC resistance spot welding by using high speed filming

    S.C.A. Alfaro

    2007-09-01

    Full Text Available Purpose: In this work it will be carried through the filming of the formation and growth of the nugget in resistance spot welding executed in AC and MF. A comparison for same times in both the processes will be carried through to verify which of the used processes offers better conditions, control and results as well as will help for one better understanding of the process aiming at the otimização.Design/methodology/approach: Two different spot welding machine (AC and MF-DC had been used, and a digital high-speed camera. The weld points had been carried through in 3 galvanized steel different plate configurations. The electrodes had been truncated to obtain one better visualization for the weld nugget formation. The comparison of the formation and development between the weld point of each process (AC and MF is shown in 7 pictures in the same values of time.Findings: For currents below 2 kA, no nugget was observed. and the formation of same after 10º cycle for bigger current of 3 kA. The MF-DC welding offers the possibility of obtaining nuggets more uniforms within shorter times (depending on the plate configuration.Research limitations/implications: In this work the AC machine is limited by the values of current of welding and pressure of the electrodes: (2 - 6 kA e (87 - 261 kgf respectively. Other materials: aluminum, stainless steel or material exactly dissimilar could be used following the line of this research. Bigger currents levels can also be used.Originality/value: The idea to compare resulted for the same process of welding under different conditions (equipment, materials and or parameters makes possible the choice of these better conditions used to the otimização of the process.

  1. A Study of Hydrogen Generation with Doubly-Fed Adjustable Speed Wind Generator

    Kinoshita, Hirotaka; Takahashi, Rion; Murata, Toshiaki; Tamura, Junji; Sugimasa, Masatoshi; Komura, Akiyoshi; Futami, Motoo; Ichinose, Masaya; Ide, Kazumasa

    This paper presents a combination system of wind power generator and hydrogen generator. In the proposed system, Doubly-Fed Synchronous Generator (DFSG) is used as an adjustable speed wind generator, and an electrolyzer is connected to its terminal for hydrogen generation, which is controlled by power electronic converters. Output power from the wind generator is smoothed and supplied to the power system as well as to the electrolyzer to generate hydrogen under a cooperative control of the wind generator and the electrolyzer. The performance of the proposed system is investigated by simulation analyses, in which simulations are performed by using PSCAD/EMTDC.

  2. A high speed camera with auto adjustable ROI for product's outline dimension measurement

    Wang, Qian; Wei, Ping; Ke, Jun; Gao, Jingjing

    2014-11-01

    Currently most domestic factories still manually detect machine arbors to decide if they meet industry standards. This method is costly, low efficient, and easy to misjudge the qualified arbors or miss the unqualified ones, thus seriously affects factories' efficiency and credibility. In this paper, we design a specific high-speed camera system with auto adjustable ROI for machine arbor's outline dimension measurement. The entire system includes an illumination part, a camera part, a mechanic structure part and a signal processing part based on FPGA. The system will help factories to realize automatic arbor measurement, and improve their efficiency and reduce their cost.

  3. Combinatorial Optimization Method for Operation of Pumping Station with Adjustable Blade and Variable Speed Based on Experimental Optimization of Subsystem

    Yi Gong; Jilin Cheng

    2014-01-01

    A decomposition-dynamic programming aggregation method based on experimental optimization for subsystem was proposed to solve mathematical model of optimal operation for single pumping station with adjustable blade and variable speed. Taking minimal daily electric cost as objective function and water quantity pumped by units as coordinated variable, this model was decomposed into several submodels of daily optimal operation with adjustable blade and variable speed for single pump unit which w...

  4. Investigation of Electrode Erosion Mechanism of Multi-Phase AC Arc by High-Speed Video Camera

    A multi-phase AC arc has been applied to the glass melting technology. However, the electrode erosion is one of the most considerable issues to be solved. In order to investigate the erosion mechanism of the multi-phase AC arc, the combination of the high-speed video camera and the band-pass filters was introduced to measure the electrode temperature. Results indicated the tip temperature of the electrode surface in the 12-phase arc was lower than that in the 2-phase arc, while erosion rate in 12-phase arc was higher than that in the 2-phase arc. Furthermore, the dynamic behaviour of the vapours in the arc was investigated by using the same high-speed camera system. The tungsten electrode mainly evaporates at the anodic period during AC cycle. The oxygen concentration in the arc increases with larger number of the phases, resulting in the higher erosion rate in the 12-phase arc.

  5. Passive wide spectrum harmonic filter for adjustable speed drives in oil and gas industry

    Al Jaafari, Khaled Ali

    Non-linear loads such as variable speed drives constitute the bulky load of oil and gas industry power systems. They are widely used in driving induction and permanent magnet motors for variable speed applications. That is because variable speed drives provide high static and dynamic performance. Moreover, they are known of their high energy efficiency and high motion quality, and high starting torque. However, these non-linear loads are main sources of current and voltage harmonics and lower the quality of electric power system. In fact, it is the six-pulse and twelve-pulse diode and thyristor rectifiers that spoil the AC power line with the dominant harmonics (5th, 7th, 11th). They provide DC voltage to the inverter of the variable speed drives. Typical problems that arise from these harmonics are Harmonic resonances', harmonic losses, interference with electronic equipment, and line voltage distortion at the Point of Common Coupling (PCC). Thus, it is necessary to find efficient, reliable, and economical harmonic filters. The passive filters have definite advantage over active filters in terms of components count, cost and reliability. Reliability and maintenance is a serious issue in drilling rigs which are located in offshore and onshore with extreme operating conditions. Passive filters are tuned to eliminate a certain frequency and therefore there is a need to equip the system with more than one passive filter to eliminate all unwanted frequencies. An alternative solution is Wide Spectrum Harmonic passive filter. The wide spectrum harmonic filters are becoming increasingly popular in these applications and found to overcome some of the limitations of conventional tuned passive filter. The most important feature of wide spectrum harmonic passive filters is that only one capacitor is required to filter a wide range of harmonics. Wide spectrum filter is essentially a low-pass filter for the harmonic at fundamental frequency. It can also be considered as a

  6. A New Low-Cost Hybrid Switched Reluctance Motor for Adjustable-Speed Pump Applications

    Lu, Kaiyuan; Rasmussen, Peter Omand; Watkins, Steve;

    2011-01-01

    This paper presents a new low-cost hybrid switched reluctance (HSR) motor intended for use in adjustable-speed pump drive systems. The motor is a single-phase motor, driven by a unipolar converter, which uses both the reluctance torque and the permanent magnet interaction torque. Compared...... with conventional single-phase switched reluctance motors, it has an increased torque density. The cogging torque is beneficially used in this motor for reducing the torque ripple. It is demonstrated that such a motor drive system can be a suitable candidate to advantageously compete with the existing motor drive...... systems for low-cost applications. Finite-element models are used to analyze and predict the motor's performance. The proposed motor drive system has been fabricated, and its performance has been tested in the laboratory. These experimental results are also presented....

  7. Commutation effect of Adjustable Speed Drives due to installation of active harmonic filters

    Asiminoaei, Lucian; Kalaschnikow, Sergej; Hansen, Steffan;

    2011-01-01

    The success of designing an industrial installation with Active Filters depends on how precise the load profile of the application is known, because this determines the amount of harmonic currents to be compensated. However, once the Active Filter is added to the installation, the harmonic currents...... may increase due to changes in the commutation behavior of diode rectifier converters. The change of natural commutation determines higher harmonics currents of the diode rectifiers and therefore higher harmonic loading of the Active Filter in the installation. This paper presents a method to estimate...... the commutation behavior of Adjustable Speed Drives when their harmonic currents are compensated by a Shunt Active Filter. The method is formulated as an analytical computation algorithm verified by simulations. Further on the method is implemented in a Harmonic Calculation Toolbox which facilitates...

  8. Feedforward Synchronised PWM for Adjustable Speed AC Drives with Different Control Modes

    Oleschuk, Valentin; Blaabjerg, Frede; Jensen, Flemming Buus

    2002-01-01

    This paper presents a novel method of direct synchronised pulswidth modulation (PWM) for three-phase voltage source inverters, feeding induction motors with different control regimes. It is based on the universal algorithm with either simplified algebraic or accurate trigonometric control functions......, with vector approached for determination of the pulse patterns, with vector approach for determination of the pulse patterns. Different control modes of the drive system with synchronised PWM, including standard scalar V/F control, and also V2/F = constant and V/F2 = constant control regimes, have been...... analysed in the paper. Simulations give the behaviour of the PWM techniques proposed. Both continuous and discontinuous schemes of synchronised PWM, applied for the corresponding control regime, have been analysed and compared....

  9. An EMC Evaluation of the Use of Unshielded Motor Cables in AC Adjustable Speed Drive Applications

    Hanigovszki, Norbert; Poulsen, J.; Spiazzi, G.;

    2004-01-01

    -phase applications the occurrence of common-mode voltage is inherent due to asymmetrical output pulses. As a result, for electromagnetic compatibility (EMC) reasons, in most applications shielded cables are used between the inverter and the motor, implying high installation costs. The present paper discusses the use...... of cheaper, unshielded cables. A new method for measuring electromagnetic interference (EMI) from unshielded cables is proposed and measurement results are presented. The level of EMI is evaluated in different situations: without an output filter, with a classical LC output filter and with an...

  10. 400-MW adjustable-speed pumped-storage hydraulic power plant

    Kita, E. [Kansai Electric Power Co. Inc., Osaka (Japan); Bando, A.; Kuwabara, T. [Hitachi, Ltd., Tokyo (Japan)

    1995-02-01

    The performance of the 400 MW adjustable-speed pumped-storage hydraulic power plant of Okawachi Power Station, Kansai Electric Power Co., Inc., Japan is outlined. The plant adopts a cycloconverter for an exciter, and uses selectively one of three real power control modes such as fixed-frequency excitation, synchronous speed control and slip-phase control according to internal phase angles. The plant also adopts the operation mode giving priority to quick response to output commands, and the stator frequency detecting mode giving priority to response to power systems. The plant maintains an AFC capacity of {plus_minus}80 MW during pumping operation, and satisfies the intended performance requirements in both generating and pumping modes. The overcurrent and overvoltage protection systems of which functions were ascertained to be effective through power system tests, are used to eliminate side effects due to use of the cycloconverter for an exciter. The specific transient phenomenon analysis system is also used for supporting maintenance works. 5 refs., 12 figs., 2 tabs.

  11. Dynamic melting and impurity particle tracking in continuously adjustable AC magnetic field

    Bojarevics, V.; Pericleous, K.

    2016-07-01

    The analysis of semi-levitation melting is extended to account for the presence of particles (impurities, broken metal dendrite agglomerates, bubbles) during the full melting cycle simulated numerically using the pseudo-spectral schemes. The AC coil is dynamically moving with the melt front progress, while the generated Joule heat serves to enhance the melting rate. The electromagnetic force is decomposed into the time average and the oscillating parts. The time average effects on the particle transport are investigated previously using approximations derived for a locally uniform magnetic field. This paper presents expressions for the skin-layer type of the AC force containing also the pulsating part which contributes to the particle drag by the ‘history’ and ‘added mass’ contributions. The intense turbulence in the bulk of molten metal additionally contributes to the particle dispersion. The paper attempts to demonstrate the importance of each of the mentioned effects onto the particle transport during the melting until the final pouring stage. The method could be extended to similar AC field controlled melting/solidification processes.

  12. Evaluation of the Ride-Through Capability of an Active-Front-End Adjustable Speed Drive under Real Grid Conditions

    Liserre, Marco; Klumpner, Christian; Blaabjerg, Frede;

    2004-01-01

    Better quality of the input currents, unity power factor and regenerative capability are not the only benefits of equipping an Adjustable Speed Drive (ASD) with an active front-end-stage. Controlling the power inflow may enable also the reduction of the dc-link energy storage, which will then lead...

  13. Analysis of cutting-edge techniques in the high voltage and high power adjustable speed drive systems

    2009-01-01

    The high voltage and high power adjustable speed drive (ASD) system is one of the most attractive fields in power electronics, and it is also a very crucial technique for energy saving and emission reduction. This paper discussed and analyzed the main cutting-edge knowledge and issues in the process of exploiting the high voltage and high power ASD system.

  14. The Single-Phase AC-DC Conversion Circuit with Power Factor Adjustable%功率因数可调单相AC-DC变换电路∗

    杨力; 张师斌; 赵宁

    2015-01-01

    This design is a single-phase AC-DC conversion circuit with power factor adjustable based on UCC28019A. MSP430 is selected as the control core. We adopt the high precision 24-bitΣ-ΔADC to measure the input voltage RMS,the input current RMS,the active power RMS,the power factor and some other parameters. The power-factor correction is accomplished by UCC28019A. By controlling the digital phase shift circuit to shift the phase of the current feedback signal,the power factor can be set in the range of 0.8 to 1.0. By detecting the output current and voltage,the circuit has the function of 2.5A overcurrent protection and 36V regulated output.%基于UCC28019A设计的功率因数可调单相AC-DC变换电路。 MSP430单片机作为其控制核心,使用高精度24 bitΣ-Δ型ADC采样,可完成对输入电压有效值、输入电流有效值、有功功率有效值、功率因数等参数的测量。由UCC28019A完成功率因数的校正,通过控制数字移相电路对外围电流反馈信号移相,实现功率因数在0.8~1.0范围内的调整。本设计还可通过对输出电流和电压的监测,实现2.5 A过流保护和36 V稳压输出的功能。

  15. IEEE 802.11ac: Next Generation High Speed Wireless LAN Technology

    Ms. Laxmi Chaudhary

    2015-06-01

    Full Text Available This paper gives an overview of the IEEE 802.11ac which has been proposed to enhance the throughput of IEEE 802.11n beyond Gigabit-per second rates. 802.11ac adds multi-user access techniques in the form of downlink multi-user (DL MU multiple input multiple output (MIMOand 80 and 160 MHz channels in the 5 GHz band for applications such as multiple simultaneous video streams throughout the home. For this the IEEE 802.11ac task group is working on the amendment that has goal of reaching maximum network throughput of atleast 1 Gbps on bands below 6GHz & continuing to support the legacy of 5GHz 802.11 devices. In this paper we describe the 802.11ac key features, channelization, MAC modifications and modulation enhancements and its various applications in wireless technology.

  16. Establishing force and speed training targets for lumbar spine high-velocity, low-amplitude chiropractic adjustments*

    Owens, Edward F.; Hosek, Ronald S.; Sullivan, Stephanie G.B.; Russell, Brent S.; Mullin, Linda E.; Dever, Lydia L.

    2016-01-01

    Objective: We developed an adjusting bench with a force plate supporting the lumbar portion to measure loads transmitted during lumbar manual adjustment. It will be used to provide force-feedback to enhance student learning in technique labs. The study goal is to define the learning target loads and speeds, with instructors as expert models. Methods: A total of 11 faculty members experienced in teaching Gonstead technique methods performed 81 simulated adjustments on a mannequin on the force plate. Adjustments were along 9 lumbopelvic “listings” at 3 load levels: light, normal, and heavy. We analyzed the thrusts to find preload, peak load, duration, and thrust rate. Results: Analysis of 891 thrusts showed wide variations between doctors. Peak loads ranged from 100 to 1400 N. All doctors showed clear distinctions between peak load levels, but there was overlap between high and low loads. Thrust rates were more uniform across doctors, averaging 3 N/ms. Conclusion: These faculty members delivered a range of thrusts, not unlike those seen in the literature for high velocity, low amplitude manipulation. We have established at least minimum force and speed targets for student performance, but more work must be done to create a normative adjustment to guide refinement of student learning. PMID:26600272

  17. Adjustable-Speed Single-Phase IM Drive with Reduced Number of Switches

    Chomát, Miroslav; Lipo, T. A.

    2003-01-01

    Roč. 39, č. 3 (2003), s. 819-825. ISSN 0093-9994 R&D Projects: GA ČR GA102/02/0554 Grant ostatní: National Science Foundation(US) GA9820434 Institutional research plan: CEZ:AV0Z2057903 Keywords : AC motor drives * converters * induction motor drives Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.783, year: 2003

  18. Shunt active filter algorithms for a three phase system fed to adjustable speed drive

    Sujatha.CH; Sravanthi.Kusam; Dr. K.Chandra shek

    2011-01-01

    This paper presents the simulation of Shunt Active Power filter by using two different control schemes, Indirect current control technique and Synchronous detection technique by using ANN. These two control techniques are working under both balanced and unbalanced three phase voltage source conditions and it is feeding to aadjustable speed drive the torque speed characteristics of a motor is presented. Indirect current control technique is implemented under dynamic load condition and load bal...

  19. Dynamic Modeling of Adjustable-Speed Pumped Storage Hydropower Plant: Preprint

    Muljadi, E.; Singh, M.; Gevorgian, V.; Mohanpurkar, M.; Havsapian, R.; Koritarov, V.

    2015-04-06

    Hydropower is the largest producer of renewable energy in the U.S. More than 60% of the total renewable generation comes from hydropower. There is also approximately 22 GW of pumped storage hydropower (PSH). Conventional PSH uses a synchronous generator, and thus the rotational speed is constant at synchronous speed. This work details a hydrodynamic model and generator/power converter dynamic model. The optimization of the hydrodynamic model is executed by the hydro-turbine controller, and the electrical output real/reactive power is controlled by the power converter. All essential controllers to perform grid-interface functions and provide ancillary services are included in the model.

  20. High-Speed Visualization of Evaporation Phenomena from Tungsten Based Electrode in Multi-Phase AC Arc

    Tanaka, Manabu; Hashizume, Taro; Imatsuji, Tomoyuki; Nawata, Yushi; Watanabe, Takayuki

    2015-09-01

    A multi-phase AC arc has been developed for applications in various fields of engineering because it possesses unique advantages such as high energy efficiency. However, understanding of fundamental phenomena in the multi-phase AC arc is still insufficient for practical use. Purpose of this study is to investigate electrode erosion mechanism by high-speed visualization of the electrode metal vapor in the arc. Results indicated that the electrode mainly evaporated at anodic period, leading to the arc constriction. Moreover, evaporation of W electrode with 2wt% La2O3 at the anodic period was much higher than that with 2wt% ThO2. This can be explained by different properties of these oxide additives. Evaporation of the oxide additive resulted in the arc constriction, which accelerated the evaporation of W electrode. Therefore, addition of La2O3 with lower melting and boiling point than ThO2 lead to stronger arc constriction, resulting in severer evaporation of W electrode.

  1. A Novel Adjustment Method for Shearer Traction Speed through Integration of T-S Cloud Inference Network and Improved PSO

    Lei Si

    2014-01-01

    Full Text Available In order to efficiently and accurately adjust the shearer traction speed, a novel approach based on Takagi-Sugeno (T-S cloud inference network (CIN and improved particle swarm optimization (IPSO is proposed. The T-S CIN is built through the combination of cloud model and T-S fuzzy neural network. Moreover, the IPSO algorithm employs parameter automation adjustment strategy and velocity resetting to significantly improve the performance of basic PSO algorithm in global search and fine-tuning of the solutions, and the flowchart of proposed approach is designed. Furthermore, some simulation examples are carried out and comparison results indicate that the proposed method is feasible, efficient, and is outperforming others. Finally, an industrial application example of coal mining face is demonstrated to specify the effect of proposed system.

  2. Adjusting for car occupant injury liability in relation to age, speed limit, and gender-specific driver crash involvement risk.

    Keall, Michael; Frith, William

    2004-12-01

    It is well established that older drivers' fragility is an important factor associated with higher levels of fatal crash involvement for older drivers. There has been less research on age-related fragility with respect to the sort of minor injuries that are more common in injury crashes. This study estimates a quantity that is related to injury fragility: the probability that a driver or a passenger of that driver will be injured in crashes involving two cars. The effects of other factors apart from drivers' fragility are included in this measure, including the fragility of the passengers, the crashworthiness of cars driven, seatbelt use by the occupants, and characteristics of crashes (including configuration and impact speed). The car occupant injury liability estimates appropriately includes these factors to adjust risk curves by age, gender, and speed limit accounting for overrepresentation in crashes associated with fragility and these other factors. PMID:15545071

  3. A Review of Electronic Inductor Technique for Power Factor Correction in Three-Phase Adjustable Speed Drives

    Davari, Pooya; Yang, Yongheng; Zare, Firuz;

    2016-01-01

    Electronic Inductor (EI) techniques are promising approaches for improving the grid-side current quality, and they are suitable for motor drive applications. In this paper, different EI topologies are investigated from the efficiency perspective, including the effect of employing Silicon Carbide...... (SiC) power devices. Moreover, the influence of partial loading on component sizing in Adjustable Speed Drives (ASDs) is studied. Finally the analytical loss modelling of power switches is utilized for efficiency measurement. The theoretical analyses are verified by experimental benchmarking in an ASD...

  4. Free-standing few-layered graphene oxide films: selective, steady and lasting permeation of organic molecules with adjustable speeds

    Huang, Tao; An, Qi; Luan, Xinglong; Zhang, Qian; Zhang, Yihe

    2016-01-01

    A variety of small molecules with diameters around 1 nm possess a range of functions, such as antibiotic, antimicrobic, anticoagulant, pesticidal and chemotherapy effects, making these molecules especially useful in various applications ranging from medical treatment to environmental microbiological control. However, the long-term steady delivery (release or permeation) of these small molecules with adjustable and controllable speeds has remained an especially challenging task. In this study, we prepared covalently cross-linked free-standing few-layered GO films using a layer-by-layer technique in combination with photochemical cross-linkages, and achieved a controlled release of positively charged, negatively charged, and zwitterionic small molecules with adjustable and controllable speeds. The steady delivery of the small molecule lasted up to 9 days. Other functionalities, such as graphene-enhanced Raman spectra and electrochemical properties that could also be integrated or employed in delivery systems, were also studied for our films. We expect the special molecular delivery properties of our films to lead to new possibilities in drug/fertilizer delivery and environmental microbiological control applications.A variety of small molecules with diameters around 1 nm possess a range of functions, such as antibiotic, antimicrobic, anticoagulant, pesticidal and chemotherapy effects, making these molecules especially useful in various applications ranging from medical treatment to environmental microbiological control. However, the long-term steady delivery (release or permeation) of these small molecules with adjustable and controllable speeds has remained an especially challenging task. In this study, we prepared covalently cross-linked free-standing few-layered GO films using a layer-by-layer technique in combination with photochemical cross-linkages, and achieved a controlled release of positively charged, negatively charged, and zwitterionic small molecules with

  5. Modulation of Premotor and Primary Motor Cortical Activity during Volitional Adjustments of Speed-Accuracy Trade-Offs.

    Thura, David; Cisek, Paul

    2016-01-20

    Recent work suggests that while animals decide between reaching actions, neurons in dorsal premotor (PMd) and primary motor (M1) cortex reflect a dynamic competition between motor plans and determine when commitment to a choice is made. This competition is biased by at least two sources of information: the changing sensory evidence for one choice versus another, and an urgency signal that grows over time. Here, we test the hypothesis that the urgency signal adjusts the trade-off between speed and accuracy during both decision-making and movement execution. Two monkeys performed a reaching decision task in which sensory evidence continuously evolves over the course of each trial. In different blocks, task timing parameters encouraged monkeys to voluntarily adapt their behavior to be either hasty or conservative. Consistent with our hypothesis, during the deliberation process the baseline and gain of neural activity in decision-related PMd (29%) and M1 cells (45%) was higher when monkeys applied a hasty policy than when they behaved conservatively, but at the time of commitment the population activity was similar across blocks. Other cells (30% in PMd, 30% in M1) showed activity that increased or decreased with elapsing time until the moment of commitment. Movement-related neurons were also more active after longer decisions, as if they were influenced by the same urgency signal controlling the gain of decision-related activity. Together, these results suggest that the arm motor system receives an urgency/vigor signal that adjusts the speed-accuracy trade-off for decision-making and movement execution. Significance statement: This work addresses the neural mechanisms that control the speed-accuracy trade-off in both decisions and movements, in the kinds of dynamic situations that are typical of natural animal behavior. We found that many "decision-related" premotor and motor neurons are modulated in a time-dependent manner compatible with an "urgency" signal that

  6. Limitation of Adjustable-Speed Drive Operation by Unbalanced Voltage Supply

    Chomát, Miroslav; Schreier, Luděk; Bendl, Jiří

    Piscataway : IEEE, 2008, s. 1-6. ISBN 978-1-4244-1736-0. [International Conference on Electrical Machines - ICEM 2008 /18./. Vilamoura (PT), 06.09.2008-09.09.2008] R&D Projects: GA ČR GA102/06/0215 Institutional research plan: CEZ:AV0Z20570509 Keywords : unbalanced voltage supply * DC-link voltage pulsations * variable-speed drive Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering www.apdee.org

  7. New possibilities with new technology: the Adjustable Speed Hydro (ASH) generator

    Generators with variable rotational speed can be the solution for the Norwegian power system. The technology is available and is already used abroad. As with all projects, investing in ASH must be based on economic profitability, where all advantages and disadvantages are considered, and on thorough techno-economic analyses. The article describes the fundamental principles of the ASH, its advantages, and discusses its possible installation in already existing power stations

  8. A New Generalized Two-Stage Direct Power Conversion Topology to Independently Supply Multiple AC Loads from Multiple Power Grids with Adjustable Power Loading

    Klumpner, Christian; Blaabjerg, Frede

    2004-01-01

    Normally, a power converter has one supply port to connect to the power grid and one output port to connect to an AC load that requires variable voltage and variable frequency. Converter topologies with multiple output ports, the so-called multi-drive converters are also used in order to share the...... cost of an active front-end rectifier. As the trend on the energy market is towards deregulation, new converter topologies are needed to allow independent producers/consumers to connect to multiple distribution grids in order to minimize the electricity price. Having the possibility to adjust smoothly...... angle) and continuously adjust these power fractions will become a desired feature. This paper presents a generalized Direct Power Converter topology, which is able to connect to multiple AC supplies proving complete decoupling and no circulating power between the input ports and to independently...

  9. Stabilization of multi-machine power system by coordinated excitation control of multiple adjustable-speed generator/motors; Fukusu kahensoku hatsuden dendoki no reiji den`atsu kyocho seigyo ni yoru taki keito anteika

    Tatematsu, M.; Yokoyama, A. [The University of Tokyo, Tokyo (Japan)

    1996-01-20

    Since an adjustable-speed generator/motor (ASGM) is excited by AC voltage fed by a quick-response cycloconverter, a rotating speed of the rotor can be changed continuously. The ASGMs installed at some pumping-up power stations are now operated effectively for automatic frequency control under the lightly loaded condition at night by changing the pumping-up power due to the rotating speed change. It is expected, on the other hand, that under the generating condition in the daytime the ASGM will be used for enhancement of transient stability because it can generate or absorb active and reactive power independently of each other by AC excitation voltage control. This paper proposes a novel control method of excitation system of ASGM for improving the transient stability of a multi-machine power system including multiple ASGMs. The controller which is designed based on an energy function works well for the stability enhancement. In comparison with the conventional excitation control of synchronous generator and constant output control of ASGM, the effectiveness of the proposed method is shown by digital simulations. 10 refs., 5 figs., 2 tabs.

  10. Buck-Boost Control of Four Quadrant Chopper using Symmetrical Impedance Network for Adjustable Speed Drive

    Saswati Swapna Dash; Byamakesh Nayak

    2015-01-01

    This paper proposes buck-boost capabilities of four quadrant chopper for wide range speed control of DC motor drives using symmetrical impedance network called Z-source network. By controlling the shoot through duty ratio from 0 to 0.5 and non-shoot through techniques, the Z-source four quadrant choppers can produce any desired DC voltage across the DC motor. The switching patterns for both buck and boost operations are presented to achieve four modes of operation of DC motor. As a result, th...

  11. Buck-Boost Control of Four Quadrant Chopper using Symmetrical Impedance Network for Adjustable Speed Drive

    Saswati Swapna Dash

    2015-02-01

    Full Text Available This paper proposes buck-boost capabilities of four quadrant chopper for wide range speed control of DC motor drives using symmetrical impedance network called Z-source network. By controlling the shoot through duty ratio from 0 to 0.5 and non-shoot through techniques, the Z-source four quadrant choppers can produce any desired DC voltage across the DC motor. The switching patterns for both buck and boost operations are presented to achieve four modes of operation of DC motor. As a result, the proposed model will have ride through capability during voltage sags, manage during voltage swells, used in any types of DC voltage sources such as fuel cell and solar cell and improve the reliability by reducing EMI noise. Analysis and simulation results are presented to demonstrate these new findings.

  12. The Use of Active Elements to Reduce the Size and Weight of Passive Components in Adjustable Speed Drives

    Maheshwari, Ram Krishan

    shaft voltage, the common mode voltage, the conducted emissions, and the efficiency of the two systems are compared since they are major factors which affect the size of the passive components in the drives. Although the three-level inverter requires higher number of active components as compared to the......Adjustable speed drives are considered as workhorse of industry due to various applications in different kind of industries. According to a market survey, low voltage drives are most profitable in the drive industries. The drive consists of a machine and a converter, which processes grid power and...... converts into usable power for the machine. The converter consists of active and passive components. The size, weight, and volume of the drive are decided by the passive components since they typically contribute to 75% of the weight and volume of the drive. Most popular topology for the low voltage drive...

  13. 交流异步电动机调速系统控制策略综述%Review of AC asynchronous motor speed control strategy

    丁辉; 胡协和

    2011-01-01

    为了更精确地实现交流异步电动机调速,基于交流异步电动机的数学模型论述异步电动机变压变频(VVVF)调速系统的各种控制策略.总结早期的基于异步电机稳态模型的控制策略,介绍3种较成熟的基于动态模型的控制策略,分析现代控制理论在交流异步电动机调速系统中的应用,展望交流调速控制策略的发展方向.传统的控制策略在工业现场中的应用已经较为成熟,各种现代控制策略和先进控制算法则有广阔的发展前景.%Variable voltage variable frequency (VVVF) speed control strategies were researched based on the mathematical model of alternating current (AC) asynchronous motor in order to achieve more accurate speed control of AC induction motor. The early control methods of induction motor based on the steady-state model were simply summarized. Three mature control schemes based on the dynamic model were introduced. The application of modern control theory in AC asynchronous motor speed control system was analyzed. Finally, the future development direction of AC speed control strategy was given. Traditional strategies were maturely utilized in industrial field, but the modern control theory and advanced control algorithms still have vast potential for future development.

  14. Effects of priming exercise on the speed of adjustment of muscle oxidative metabolism at the onset of moderate-intensity step transitions in older adults.

    De Roia, Gabriela; Pogliaghi, Silvia; Adami, Alessandra; Papadopoulou, Christina; Capelli, Carlo

    2012-05-15

    Aging is associated with a functional decline of the oxidative metabolism due to progressive limitations of both O(2) delivery and utilization. Priming exercise (PE) increases the speed of adjustment of oxidative metabolism during successive moderate-intensity transitions. We tested the hypothesis that such improvement is due to a better matching of O(2) delivery to utilization within the working muscles. In 21 healthy older adults (65.7 ± 5 yr), we measured contemporaneously noninvasive indexes of the overall speed of adjustment of the oxidative metabolism (i.e., pulmonary Vo(2) kinetics), of the bulk O(2) delivery (i.e., cardiac output), and of the rate of muscle deoxygenation (i.e., deoxygenated hemoglobin, HHb) during moderate-intensity step transitions, either with (ModB) or without (ModA) prior PE. The local matching of O(2) delivery to utilization was evaluated by the ΔHHb/ΔVo(2) ratio index. The overall speed of adjustment of the Vo(2) kinetics was significantly increased in ModB compared with ModA (P ModA (P < 0.05), suggesting an improved O(2) delivery. Our data are compatible with the hypothesis that, in older adults, PE, prior to moderate-intensity exercise, beneficially affects the speed of adjustment of oxidative metabolism due to an acute improvement of the local matching of O(2) delivery to utilization. PMID:22422668

  15. Six-step Voltage Control of PM Brushless AC Motors under High Speed Flux-weakening Operation for EV/HEV Applications

    诸自强

    2008-01-01

    The torque-speed characteristics of brushless motor having an interior permanent magnet rotor and a sinusoidalback-emf waveform are compared experimentally when it is operated in brushless AC (BLAC) mode and brushless DC(BLDC) modes with both 2-phase, 120° conduction (BLDC-120) and 3-phase,180° conduction (BLDC-180).Particularemphasis is on high-speed,six-step voltage controlled,flux-weakening operation.h is shown that for EV/HEV applications,even for interior PM brushless motors which have sinusoidal back-emf waveforms,in order to achieve maximum torque perampere capability over wide operation speed range,it is advantageous to employ a hybrid operation mode-BLAC operationin the constant torque region and six-step voltage control (BLDC-180 operation, together with current phase control) inthe flux-weakening region.

  16. Power compensation effect of an adjustable-speed rotary condenser with a flywheel for a large capacity magnet power supply

    Akagi, Hirofumi; Sato, Hikaru

    1999-01-01

    Direct connection of the synchrotron magnet power supply to the utilities causes the effect of pulsed reactive and active power in the AC line. Conventionally, Static Var Control system compensates the reactive power generated by the thyristor converter to reduce the flicker in the power line. However, it is necessary to control not only a reactive power but also an active power for the future large scale synchrotron magnet power supply in order to reduce the dissipation power and to realize ...

  17. Possibilities of increased power output from existing generator plants. Feasible changes of existing generators. New technology, ASD (Adjustable Speed Drives); Muligheter for oekt effekt fra eksisterende generatoranlegg. Mulige endringer av bestaaende generatorer. Ny teknologi, ASD (Adustable Speed Drives)

    Elstroem, A.

    1996-12-31

    The present paper relates to the increase of power output from existing generator plants in Norway by new operation profiles. The paper focuses on the consequences of increasing the power turnover and production with a particular attention to the generator itself. In addition, some of the possibilities on the use of an ASD (Adjustable Speed Drives) installation are elucidated, which is a concept on regulating the number of revolutions within small limits by synchronous rotation. According to the author, the power output of generator increases between 10 to 30%

  18. Structure of 15-Level Sub-Module Cascaded H-Bridge Inverter for Speed Control of AC Drive Applications

    R. Uthirasamy

    2015-02-01

    Full Text Available This paper deals with the implementation of a single phase 15-level Sub-Multilevel Cascaded H-Bridge Inverter (SMCHBI for variable speed industrial drive applications. It consists of sub-multilevel modules and H-bridge inverter configuration. Sub-multilevel switches synthesize stepped DC link voltage and current from the DC sources. H-bridge inverter switches renovate stepped DC link voltage and current into sinusoidal waveform. Compared with conventional Cascaded Multilevel Inverter (CMLI, the proposed system employs the reduced number of power switches, DC sources and gate driver requirements. The proposed system not only reduces the overall system cost but also reduces the voltage stress across the inverter switches. The proposed system does not required additional resonant soft switching circuits for Zero Voltage Switching (ZVS of inverter. In the proposed method, variable frequency method is adopted for the speed control of industrial induction motor drives. A prototype model of 15-level SMCHB is developed and the performance of the systems is validated experimentally.

  19. SYSTEMS FOR THE ADJUSTMENT OF THE MAIN KINEMATIC CHAIN OF THE VERTICAL TURNING LATHES

    Dan PRODAN

    2011-07-01

    Full Text Available This paperwork presents some systems for the adjustment of the main kinematic chains of theVertical Turning Lathes that have been used within the last 20 years. There are presented adjustment systemsused when having the machine equipped with older type motors, with only one speed, and also modern systemsfor which A.C. motors with the speed adjustable by frequency variation are needed. It insists on the presentrole of the “gearboxes” as torque multipliers and not as speed reducer.

  20. 炼钢转炉除尘风机的变频调速节能运行%OPERATION OF ELECTRICITY-SAVING OF AC FREQUENCY MODULATION FOR SPEED REGULATION OF DEDUSTING FAN OF STEEL-MAKING CONVERTER

    陈乐柱

    2001-01-01

    介绍了转炉炼钢的工况及节能特点,提出了变频调速在转炉除尘风机上的实施及使用方法。%The paper introduces the working process and electricity-saving characteristics of steel-making,and puts forward the operation and application of AC frequency modulation for speed regulation used in dedusting fan of converter.

  1. Modern control theory and speed adjustment of AC motor%现代控制理论与交流电机调速(Ⅰ)

    黄济荣

    2005-01-01

    自适应控制作为现代控制理论的一个分支,在电机调速系统中起着重要的作用.特别是在磁场定向解耦控制中,通过自适应控制或校正技术将能够正确决定磁场的位置和大小,保证磁场与转矩的解耦控制.文章的这一部分从电机的动态模型和状态方程出发,阐明参数随工作点变化而呈现的不确定性的特点;并着重介绍自适应控制或校正算法的原理和方法应用.

  2. Fault Tolerant Three-Phase AC Motor Drive Topologies:A Comparison of Features, Cost, and Limitations

    2005-01-01

    THE RELIABILITY of adjustables peed ac motor drives is an area of great interest for all members of the drives community and marketplace. This is particularly the case for the military, aerospace and automotive industries that are increasingly adopting variable speed drives in order to improve overall system efficiency and performance. There are certain safety critical applications such as steering, fuel pumps,

  3. 基于剔除机械效应的资本结构调整速度再检验%The Retest of Capital Structure′s Adjustment Speed Based on Exclusion of Mechanical Effects

    顾乃康; 邓剑兰

    2014-01-01

    The reason why research on capital structure′s adjustment speed has not yet won unanimous conclusion is that there may be a “mechanical effect” in conventional partial adjustment model .By decomposing the accounting identity of asset-liability ratio, this paper eliminates the mechanical effects caused by the change in asset size .And based on panel data of listed compa-nies in Shenzhen Stock Market and Shanghai Stock Market from 1998 to 2011 which issue A-shares only , this paper uses the two-stage estimation method to retest the adjustment speed and mean reversion of capital structure which are caused by active finan -cing behaviors of corporates .The empirical results show that:The adjustment speed of capital structure is about 13%under tra-ditional estimation which uses the change of asset-liability ratio as the dependent variable;but after excluding mechanical effects caused by changes in assets , the adjustment speed significantly drops to around 5%.The results show that , by excluding such mechanical effects , the corporate financing behaviors still induce mean reversion phenomenon of capital structure , but the speed of adjustment is so low that the trend of mean reversion is not obvious .%关于资本结构调整速度的研究至今仍未获得一致结论的原因之一在于传统的部分调整模型可能存在机械效应。通过对账面资产负债率的会计恒等式进行分解,剔除由资产规模变动引起的机械效应,在此基础上以1998年至2011年中国仅发行A股的非金融类上市公司面板数据为样本,采用两阶段估计法重新检验企业主动的融资行为对资本结构调整速度和均值反转的影响。研究结果表明,在传统的采用资产负债率变动作为因变量的估计下得到的资本结构调整速度约为13%,而剔除由资产规模变动引起的机械效应之后估计得到的调整速度明显下降到5%左右。这意味着在剔除由资产规模变动引起

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

    刘刚利

    2011-01-01

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

  5. 气量无级调节系统的原理及应用%Principle and Application of HydroCOM Stepless Speed Adjustment System

    陈睿

    2012-01-01

    石油化工装置中的往复式压缩机常采用仪表阀旁路回流进行流量调节,造成大量能耗浪费。但在往复式压缩机上实施HydroCOM无级调节系统后,节能降耗效果十分显著。本文阐述了HydroCOM无级调节系统的节能原理、控制方案和联锁逻辑。%The bypass valve was often used to adjust the flow in reciprocating compressor in petrochemical plant, then a lot of energy were wasted. After HydroCOM system applied in reciprocating compressor, energy was saved a great deal. The principle of energy saving, the control program and the interlock logic were describled in detail.

  6. Relationship between robust stability and power system damping enhancement by excitation control system of adjustable-speed generator; Kahensoku hatsudenki reiji denatsu seigyo kei ni yoru denryoku keito danpingu kojo koka to robasuto anteisei no kankei

    Shigeto, T.; Yokoyama, A. [Tokyo Univ. (Japan)

    1997-12-20

    Since Adjustable-Speed Generator (ASG) is excited by alternative voltage fed by a quick-response cycloconverter, the rotor speed can be changed continuously. The ASGs installed at sonic pumping-up power stations are now utilized for Automatic Frequency Control at night time and under the light load condition by changing the pumping-up power due to the rotating speed change. It is expected. on the other hand. that under the generating condition at day time ASG will be utilized for improvement of power system stability because it can change the active power and the reactive power independently of each other. This paper presents the effect of the excitation control system of ASG designed by robust pole allocation method which is one of the controller design techniques besed on H{infinity} control theory, on the power system damping enhancement. Eigenvalue analysis and digital time simulation are carried out for 10-machine longitudinal test power system including ASGs in order to evaluate the designed controller. 5 refs., 23 figs., 5 tabs.

  7. Robust Non-Linear Direct Torque and Flux Control of Adjustable Speed Sensorless PMSM Drive Based on SVM Using a PI Predictive Controller

    F. Naceri

    2010-01-01

    Full Text Available This paper presents a new sensorless direct torque control method for voltage inverter – fed PMSM. The control methodis used a modified Direct Torque Control scheme with constant inverter switching frequency using Space Vector Modulation(DTC-SVM. The variation of stator and rotor resistance due to changes in temperature or frequency deteriorates theperformance of DTC-SVM controller by introducing errors in the estimated flux linkage and the electromagnetic torque.As a result, this approach will not be suitable for high power drives such as those used in tractions, as they require goodtorque control performance at considerably lower frequency. A novel stator resistance estimator is proposed. The estimationmethod is implemented using the Extended Kalman Filter. Finally extensive simulation results are presented to validate theproposed technique. The system is tested at different speeds and a very satisfactory performance has been achieved.

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

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

  9. ADJUSTMENT FACTORS AND ADJUSTMENT STRUCTURE

    Tao Benzao

    2003-01-01

    In this paper, adjustment factors J and R put forward by professor Zhou Jiangwen are introduced and the nature of the adjustment factors and their role in evaluating adjustment structure is discussed and proved.

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

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

    2010-01-01

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

  11. Adjustment of the Short Track Speed Skaters'Psychology in Starting%短道速滑运动员起跑心理状态的调整

    耿丽; 刘翠佳

    2011-01-01

    比赛中短道速滑的起跑,对于整个比赛的过程和最终取得成绩起着至关重要的作用。运动员起跑时不良起跑心理状态表现为训练和比赛动机障碍、过度紧张性情绪障碍、焦虑性情绪障碍、抑制障碍,提出采取消除紧张情绪、消除焦虑和畏惧情绪、生物反馈法、集中注意力、念动训练法等方法与手段调整运动员赛前的心理状态。%The starting is crucial for a short track speed skater to perform through a competition and catch the final result. The skaters'bad psychology in starting shows the motivational perplexity of training and competition, the emotional handicap of overstrain and anxiety, the disorder of inhibitory control. The paper suggests clearing up their feelings of nervousness, anxiety and fear with the methods and means of biofeedback, focusing attention, ideomotion training.

  12. Occupational Adjustment of Immigrants

    Zorlu, Aslan

    2011-01-01

    This paper examines the speed of the occupational adjustment of immigrants using Labour Force Surveys 2004 and 2005 from Statistics Netherlands. The analysis provides new evidence that immigrants start with jobs at the lower levels of skill distribution. Their occupational achievement improves significantly with the duration of residence. The extent of this initial disadvantage and the rate of adjustment vary across immigrant groups according to the transferability of skills associated with t...

  13. Research on flutter test technology of continuously adjusting dynamical pressure in high-speed wind tunnel%高速风洞连续变速压颤振试验技术研究

    郭洪涛; 闫昱; 余立; 吕彬彬; 杜宁

    2015-01-01

    针对高速暂冲式风洞阶梯变速压颤振试验用时长、耗气量大和试验模型有效使用寿命短等缺点,开展了高速暂冲式风洞连续变速压颤振试验技术研究,解决了定 Ma 数连续变速压流场控制技术与连续变速压工况下的颤振试验数据处理技术等难题。具体技术措施是:在2.4m×2.4m 暂冲式跨声速风洞中设计了基于运动函数的定Ma 数线性变总压控制策略,使 Ma 数控制精度达到了0.005以内且速压无超调,实现了流场控制目标;采用 Pick-Hold 方法构建颤振边界的亚临界预测判据,并根据预测判据近似于正态分布的特点,基于数理统计的参数估计法来减小预测判据的散布度,从而提高颤振边界亚临界预测的准确性。风洞验证试验结果表明,该试验技术达到了工程实用化水平,不仅能够取得与阶梯变速压颤振试验技术一致的结果,还能极大地节省耗气量,经济效益显著。%According to the defects shown in the flutter tests of stepped adjusting dynamical pressure in high speed intermittent wind tunnel,such as:long testing time,high gas consump-tion,and short acceptable life of testing models,researches on flutter test technology of continu-ously adjusting dynamical pressure in high-speed intermittent wind tunnels are conducted.Tech-nical problems of flutter test data processing and wind tunnel flow controlling have mainly been solved.The specific approaches are:in the 2.4m×2.4m blow off transonic wind tunnel,fixed Mach number and linear varying total pressure controlling strategies based on movement function are presented,and thus the flow controlling goal of fixed Mach number continuously adjusting dynamical pressure is achieved.The controlling uncertainty of Mach number reaches less than 0.005 without deviation of dynamical pressure.The Pick-Hold method is adopted to set up the subcritical prediction criterion in flutter boundary

  14. Research and design on synchronizing belt adjusting device of high-speed stocking machine%高速丝袜机同步带调节装置的研究与设计

    胡国军; 冯方

    2013-01-01

    根据实际生产及使用需要,要求高速丝袜机同步带的松紧能够调节。无论国内还是国外的高速丝袜机,其同步带的松紧均由机器的底座、同步带轮及同步带的制造精度所决定。而且使用一段时间后同步带有可能会松弛,严重影响机器的使用。针对这一问题,设计了一套结构简单、使用方便且可以随时调节同步带松紧的调节装置,降低了零件的生产精度,延长了同步带的使用寿命,为机器的制造商与用户提供了便利。%According to the requirement of practical production and usage ,the tightness degree for the synchronizing belt of high-speed stocking machine need adjust .Whenever the machine is manufactured at home or abroad ,the tightness of synchronizing belt is determined by the machine base ,the synchronizing belt pulley ,and the manufacturing accuracy of the belt .If the belt is used for long-time,the fatigue problem will be produced ,which could result in the serious usage .A set of creative adjusting device with the simple construct ,convenient using and timely adjusting the tightness of synchronizing belt is designed to solve the above prob -lem,which could not only decrease the production accuracy of parts ,but prolong the usage lifetime of the belt to offer the conven-ience for the machine manufacturer and custom .

  15. Convexity Adjustments

    M. Gaspar, Raquel; Murgoci, Agatha

    2010-01-01

    A convexity adjustment (or convexity correction) in fixed income markets arises when one uses prices of standard (plain vanilla) products plus an adjustment to price nonstandard products. We explain the basic and appealing idea behind the use of convexity adjustments and focus on the situations o...

  16. Adjustment disorder

    American Psychiatric Association. Diagnostic and statistical manual of mental disorders . 5th ed. Arlington, VA: American Psychiatric Publishing. 2013. Powell AD. Grief, bereavement, and adjustment disorders. In: Stern TA, Fava ...

  17. Adjustment disorder

    American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 5th ed. Arlington, Va: American Psychiatric Publishing. 2013. Powell AD. Grief, bereavement, and adjustment disorders. In: Stern TA, Rosenbaum ...

  18. Modern control theory and speed adjustment of AC motor--Nonlinear decoupling control%现代控制理论与交流电机调速(Ⅵ)--非线性解耦控制

    黄济荣

    2005-01-01

    提出一种基于微分几何的精确反馈线性化控制方法,介绍其基本概念及在交流电机调速系统中的应用原理.分析了磁场定向控制的局限性,即它只能获得渐近的输入-输出线性化和解耦.而采用基于微分几何的精确反馈线性化方法,即使在磁场变化的情况下系统暂态响应也是解耦的,这有利于改善交流电机这类具有非线性特征的电气传动系统的性能.

  19. 现代控制理论与交流电机调速(Ⅴ)--滑模变结构控制%Modern control theory and speed adjustment of AC motor --variable structure control with sliding mode

    黄济荣

    2005-01-01

    介绍变结构系统的基本概念、数学表达设计问题及其在交流电机调速系统中的应用.阐述滑模理论在变结构系统中的重要作用.指出设计变结构控制系统的核心思想是通过不连续控制,强迫这种类型的运动朝向状态空间的某个特定区域(滑动流形)并保持下去;同时指出,对于非线性不确定性系统,采用滑模变结构控制可能使跟踪误差最小化,并使复杂过程与系统控制的工程实现相对简单.

  20. Modern control theory and speed adjustment of AC motor--Intelligent control%现代控制理论与交流电机调速(Ⅳ)--智能控制(3)

    黄济荣

    2005-01-01

    针对模糊逻辑控制和神经网络控制这2种控制方法的长处和不足,人们又提出兼具两者优点的神经网络-模糊控制方法.介绍了神经网络-模糊控制系统合成推理的网络形式及一般结构,并举例阐述系统在交流电机调速中的应用情况.

  1. 现代控制理论与交流电机调速(Ⅲ)--智能控制(2)%Modern control theory and speed adjustment of AC motor--Intelligent control

    黄济荣

    2005-01-01

    介绍在交流电机调速中应用智能控制的第二部分--人工神经网络控制技术.这种网络由基本处理单元--人工神经元构成,它的输出包含一个非线性的响应函数,因此人工神经网络适于处理诸如交流电机一类具有明显非线性特征的系统.通过不同方式的训练,连续修正网络内连接权的大小,可将其用于交流电机的系统辨识和控制.

  2. 现代控制理论与交流电机调速(Ⅱ)--智能控制(1)%Modern control theory and speed adjustment of AC motor--Intelligent control

    黄济荣

    2005-01-01

    人工智能系统将进一步与电力电子学以及运动控制相结合而更加深刻地影响后者的发展.特别是在研制高质量的传动和伺服控制装置中.文章着重介绍模糊逻辑控制、神经网络控制以及它们的交叉结合的神经网络-模糊控制系统及其应用与设计.

  3. Salary adjustments

    HR Department

    2008-01-01

    In accordance with decisions taken by the Finance Committee and Council in December 2007, salaries are adjusted with effect from 1 January 2008. Scale of basic salaries and scale of stipends paid to fellows (Annex R A 5 and R A 6 respectively): increased by 0.71% with effect from 1 January 2008. As a result of the stability of the Geneva consumer price index, the following elements do not increase: a)\tFamily Allowance, Child Allowance and Infant Allowance (Annex R A 3); b)\tReimbursement of education fees: maximum amounts of reimbursement (Annex R A 4.01) for the academic year 2007/2008. Related adjustments will be applied, wherever applicable, to Paid Associates and Students. As in the past, the actual percentage increase of each salary position may vary, due to the application of a constant step value and rounding effects. Human Resources Department Tel. 73566

  4. Salary adjustments

    HR Department

    2008-01-01

    In accordance with decisions taken by the Finance Committee and Council in December 2007, salaries are adjusted with effect from 1 January 2008. Scale of basic salaries and scale of stipends paid to fellows (Annex R A 5 and R A 6 respectively): increased by 0.71% with effect from 1 January 2008. As a result of the stability of the Geneva consumer price index, following elements do not increase: a) Family Allowance, Child Allowance and Infant Allowance (Annex R A 3). b) Reimbursement of education fees: maximum amounts of reimbursement (Annex R A 4.01) for the academic year 2007/2008. Related adjustments will be implemented, wherever applicable, to Paid Associates and Students. As in the past, the actual percentage increase of each salary position may vary, due to the application of a constant step value and the rounding effects. Human Resources Department Tel. 73566

  5. Speeding Up

    YU SHUJUN

    2010-01-01

    In the wake of the global financial crisis, China has amazed the world with the speed of its economic recovery. But what has been even more surprising is the speed of its railway evolution. The unveiling of the 1,069-km Wuhan-Guangzhou High-speed Railway on December 26, 2009 pushed China's high-speed rail sys-tem-the total mileage, the average speed and the technology-to rank first in the world almost overnight.

  6. Adjustable collimator

    In a rotating fan beam tomographic scanner there is included an adjustable collimator and shutter assembly. The assembly includes a fan angle collimation cylinder having a plurality of different length slots through which the beam may pass for adjusting the fan angle of the beam. It also includes a beam thickness cylinder having a plurality of slots of different widths for adjusting the thickness of the beam. Further, some of the slots have filter materials mounted therein so that the operator may select from a plurality of filters. Also disclosed is a servo motor system which allows the operator to select the desired fan angle, beam thickness and filter from a remote location. An additional feature is a failsafe shutter assembly which includes a spring biased shutter cylinder mounted in the collimation cylinders. The servo motor control circuit checks several system conditions before the shutter is rendered openable. Further, the circuit cuts off the radiation if the shutter fails to open or close properly. A still further feature is a reference radiation intensity monitor which includes a tuning-fork shaped light conducting element having a scintillation crystal mounted on each tine. The monitor is placed adjacent the collimator between it and the source with the pair of crystals to either side of the fan beam

  7. 76 FR 74720 - Inflation Adjustment of Civil Monetary Penalties; Correction

    2011-12-01

    ..., 2009 (74 FR 38114). The rule adjusts for inflation the maximum amount of each statutory civil penalty... 46 CFR Part 506 RIN 3072-AC36 Inflation Adjustment of Civil Monetary Penalties; Correction AGENCY... Civil Penalties Inflation Adjustment Act of 1990, as amended by the Debt Collection Improvement Act...

  8. Circuit Regulates Speed Of dc Motor

    Weaver, Charles; Padden, Robin; Brown, Floyd A., Jr.

    1990-01-01

    Driving circuit regulates speed of small dc permanent-magnet motor in tape recorder. Two nested feedback loops maintain speed within 1 percent of constant value. Inner loop provides coarse regulation, while outer loop removes most of variation in speed that remains in the presence of regulation by the inner loop. Compares speed of motor with commanded speed and adjusts current supplied to motor accordingly.

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

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

    2012-01-01

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

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

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

    2010-01-01

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

  11. Measured speed versus true speed

    Perez, Israel

    2010-01-01

    The theoretical predictions, derived from the Lorentz and the Tangherlini transformations, for the one-way speed of any physical entity are confronted with the corresponding expressions for the one-way measured speed obtained from a gedanken experiment. The experiment demonstrates that, for an inertial frame $K'$ in motion relative to an inertial frame $K$ where the one-way speed of light is isotropic, even the special theory of relativity renders the one-way speed of light as function of the...

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

    Mo Yiwen

    2013-07-01

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

  13. Research on the variable speed system of large power alternating current motor%Research on the variable speed system of large power alternating current motor

    Li Chongjian

    2012-01-01

    The development status of the variable speed system of large power AC (alternating current) motor drive in China is introduced. The large power AC drive fed by AC-AC converters (cycloconverters) has developed greatly, and some innovations on the theory and engineering technique have been realized. They have been applied to rolling mills, mine hoists, and so on, and remarkable economic and social benefit has been achieved. The development of AC drive fed by large power IGCT (integrated gate commutated thyristors) AC-DC-AC converter is also introduced. It has excellent performance and reliable operation, and has been used in traction.

  14. AC electric motors control advanced design techniques and applications

    Giri, Fouad

    2013-01-01

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

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

    孟强; 廉鲁炜

    2013-01-01

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

  16. Hierarchical Control Strategy of Reactive Power for Wind Farm Based on the Front-End Speed Adjusting Wind Turbine%基于前端调速式风电机组的风电场无功分层控制策略

    燕尧; 董海鹰

    2015-01-01

    前端调速式风电机组具有较强的动态无功调节能力,针对由前端调速式风电机组组成的风电场存在随风电出力的变化引起的并网点电压波动问题,提出一种前端调速式风电场无功电压分层控制策略。该策略确定了风电场无功控制点的选取,利用风电场控制点电压偏差,通过整定控制得到整个风电场无功需求量,以风电场内有功网损最小为目标函数,采用改进的遗传算法优化分配给各台风机,并结合静止同步补偿器的无功输出来调节整个风电场的无功输出,达到维持控制点电压稳定的目的。最后以某一风电场的仿真结果验证了该策略的有效性和可行性。%The front-end speed adjusting wind turbine has strong dynamic reactive power regulation ability, aiming at prob-lems in the wind farm which consists of the front-end speed adjusting wind turbine existing the grid connection node voltage fluctuation which is caused by the change of wind power, this paper proposes a hierarchical control strategy of reactive voltage in the front-end speed adjusting wind farm.The strategy firstly determines selection of the reactive power control point in the wind farm, utilizes the voltage deviation of the wind farm control point, and obtains reactive power demand of the whole wind farm with the tuning control.The minimum real power loss of the wind farm is used as the objective function, based on the im-proved genetic algorithm optimization, and combines the reactive power output of the static synchronous compensator to adjust the reactive power output of the whole wind farm, so as to achieve the purpose of maintaining the voltage stability of the control point.The simulation results prove the feasibility and effectiveness of the strategy.

  17. Hierarchical control strategy of reactive power for wind farm based on the composition of the front-end speed adjusting wind turbine%基于前端调速式风电机组的风电场无功分层控制策略*

    燕尧; 董海鹰

    2015-01-01

    前端调速式风电机组具有较强的动态无功调节能力,针对由前端调速式风电机组组成的风电场存在随风电出力的变化而引起的并网点电压波动的问题,提出了一种前端调速式风电场无功电压分层控制策略。该策略首先确定了风电场无功控制点的选取,利用风电场控制点电压偏差,通过整定控制得到整个风电场无功需求量,以风电场内有功网损最小为目标函数,采用改进的遗传算法优化分配给各台风机,并结合静止同步补偿器的无功输出来调节整个风电场的无功输出,达到维持控制点电压稳定的目的。最后以某一风电场的仿真结果验证了该策略的有效性和可行性。%The front-end speed adjusting wind turbine has strong dynamic reactive power regulation ability. Aiming at the wind farm with the front-end speed adjusting wind turbine exists grid connection node voltage fluctuation problem caused by the change of wind power, a hierarchical control strategy of reactive voltage in the front-end speed adjusting wind farm is proposed. The strategy determines the selection of the reactive power control point in the wind farm, utilizes the voltage deviation of the wind farm control point, and obtains the reactive power demand of the whole wind farm by the tuning control. The minimum real power loss of the wind farm is used as objective function to allocate to each wind turbine based on the optimized and improved genetic algorithm. The strategy combines the reactive power output of the Static Synchronous Compensator to adjust the reactive power output of the whole wind farm and thus to achieve the purpose of maintaining the voltage stability of the control point. The simulation results prove the feasibility and effectiveness of the strategy.

  18. 基于前端调速式风电机组的风电场无功分层控制策略*%Hierarchical control strategy of reactive power for wind farm based on the composition of the front-end speed adjusting wind turbine

    燕尧; 董海鹰

    2015-01-01

    The front-end speed adjusting wind turbine has strong dynamic reactive power regulation ability. Aiming at the wind farm with the front-end speed adjusting wind turbine exists grid connection node voltage fluctuation problem caused by the change of wind power, a hierarchical control strategy of reactive voltage in the front-end speed adjusting wind farm is proposed. The strategy determines the selection of the reactive power control point in the wind farm, utilizes the voltage deviation of the wind farm control point, and obtains the reactive power demand of the whole wind farm by the tuning control. The minimum real power loss of the wind farm is used as objective function to allocate to each wind turbine based on the optimized and improved genetic algorithm. The strategy combines the reactive power output of the Static Synchronous Compensator to adjust the reactive power output of the whole wind farm and thus to achieve the purpose of maintaining the voltage stability of the control point. The simulation results prove the feasibility and effectiveness of the strategy.%前端调速式风电机组具有较强的动态无功调节能力,针对由前端调速式风电机组组成的风电场存在随风电出力的变化而引起的并网点电压波动的问题,提出了一种前端调速式风电场无功电压分层控制策略。该策略首先确定了风电场无功控制点的选取,利用风电场控制点电压偏差,通过整定控制得到整个风电场无功需求量,以风电场内有功网损最小为目标函数,采用改进的遗传算法优化分配给各台风机,并结合静止同步补偿器的无功输出来调节整个风电场的无功输出,达到维持控制点电压稳定的目的。最后以某一风电场的仿真结果验证了该策略的有效性和可行性。

  19. 基于前端调速式风电机组的风电场无功分层控制策略%Hierarchical Control Strategy of Reactive Power for Wind Farm Based on the Front-End Speed Adjusting Wind Turbine

    燕尧; 董海鹰

    2015-01-01

    The front-end speed adjusting wind turbine has strong dynamic reactive power regulation ability, aiming at prob-lems in the wind farm which consists of the front-end speed adjusting wind turbine existing the grid connection node voltage fluctuation which is caused by the change of wind power, this paper proposes a hierarchical control strategy of reactive voltage in the front-end speed adjusting wind farm.The strategy firstly determines selection of the reactive power control point in the wind farm, utilizes the voltage deviation of the wind farm control point, and obtains reactive power demand of the whole wind farm with the tuning control.The minimum real power loss of the wind farm is used as the objective function, based on the im-proved genetic algorithm optimization, and combines the reactive power output of the static synchronous compensator to adjust the reactive power output of the whole wind farm, so as to achieve the purpose of maintaining the voltage stability of the control point.The simulation results prove the feasibility and effectiveness of the strategy.%前端调速式风电机组具有较强的动态无功调节能力,针对由前端调速式风电机组组成的风电场存在随风电出力的变化引起的并网点电压波动问题,提出一种前端调速式风电场无功电压分层控制策略。该策略确定了风电场无功控制点的选取,利用风电场控制点电压偏差,通过整定控制得到整个风电场无功需求量,以风电场内有功网损最小为目标函数,采用改进的遗传算法优化分配给各台风机,并结合静止同步补偿器的无功输出来调节整个风电场的无功输出,达到维持控制点电压稳定的目的。最后以某一风电场的仿真结果验证了该策略的有效性和可行性。

  20. ACAC Converters for UPS

    Rusalin Lucian R. Păun

    2008-05-01

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

  1. Speed Control Of Induction Motor Using Dspic30f2023

    M. S. Aspalli; Laxmi

    2013-01-01

    AC motor drives are widely used to control the speed of conveyor systems, blower speeds, pump speeds, machine tool speeds and other applications that require variable speed with variable torque. The main aim of the work is to design and develop an electronic system that can be used to control the speed of a three phase induction motor.The speed of the three phase induction motor can be controlled by various methods. The stator frequency control is one of the simplest methods to control the sp...

  2. Speed mathematics

    Handley, Bill

    2012-01-01

    This new, revised edition of the bestselling Speed Mathematics features new chapters on memorising numbers and general information, calculating statistics and compound interest, square roots, logarithms and easy trig calculations. Written so anyone can understand, this book teaches simple strategies that will enable readers to make lightning-quick calculations. People who excel at mathematics use better strategies than the rest of us; they are not necessarily more intelligent. With Speed Mathematics you'll discover methods to make maths easy and fun. This book is perfect for stud

  3. Adjustments and Depression

    Full Text Available ... to my SCI? How do I deal with depression and adjustment to my SCI? ☷ ▾ Page contents The ... the moment you are injured. Understanding adjustment and depression Adjustment to paralysis is a process of changing ...

  4. ac propulsion system for an electric vehicle

    Geppert, S.

    1980-01-01

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

  5. Train Operation Adjustment Based on Conflict Resolution for High-speed Rail%高速铁路单个列车运行冲突消解研究

    文超; 彭其渊; 陈芋宏

    2013-01-01

    为研究高速铁路列车运行冲突消解问题,提出了各类列车运行冲突单个冲突的消解策略.分析了平移运行线、交换运行线、变更停站和越行方案以及数学规划方法等4种冲突策略的含义.根据冲突消解代价计算的方法,以最小冲突消解代价为优化目标,研究了高速铁路到达间隔时间冲突和出发间隔时间冲突、区间冲突、到发线运用冲突运用平移运行线、交换运行线、变更停站和越行方案等三种策略进行冲突消解的方法和过程.%In order to study the issue of train running conflict resolution of high-speed rail, the strategies of single train running conflict resolution for various types of train running conflicts is proposed. The 4 conflict resolution strategies named parallel shift of trains running lines, exchange of trains running lines, change of stopping stations and overtaking scheme, mathematical programming method are analyzed. In according to the conflict resolution cost calculation method and aimed to the minimum conflict resolution cost, the conflict resolution method and process are studied. The conflict resolution of the arrival interval conflict, departure interval conflict, section occupation conflict, arrival and departure track utilization conflict are discussed on the basis the conflict resolution strategies of parallel shift of trains running lines, exchange of trains running lines, change of stopping stations and overtaking scheme.

  6. AC power supply systems

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

  7. Adjustable hybrid diffractive/refractive achromatic lens

    Valley, Pouria; Savidis, Nickolaos; Schwiegerling, Jim; Dodge, Mohammad Reza; Peyman, Gholam; N. Peyghambarian

    2011-01-01

    We demonstrate a variable focal length achromatic lens that consists of a flat liquid crystal diffractive lens and a pressure-controlled fluidic refractive lens. The diffractive lens is composed of a flat binary Fresnel zone structure and a thin liquid crystal layer, producing high efficiency and millisecond switching times while applying a low ac voltage input. The focusing power of the diffractive lens is adjusted by electrically modifying the sub-zones and re-establishing phase wrapping po...

  8. AcEST: DK950971 [AcEST

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

  9. 银行授信影响了资本结构动态调整速度吗?--考虑样本选择偏误的实证分析%Do Lines of Credit Affect Capital Structure Adjustment Speed? Evidence from Dynamic Panel with Sample Selection

    常亮

    2015-01-01

    With the panel data of Chinese listed firms during the time period of 2001—2011, this paper empirically studies the effect of credit lines on the capital structure adjustment speed, based on the theoretical assumption that bank lines of credit could reduce financial constraints so as to reduce adjustment costs. Traditional dynamic panel estimation are flawed to the bias of sample selection, since credit firms are selected according to firm size and investment opportunity. This paper uses dynamic panel model with sample selection to overcome these shortcomings. The results show that credit firms perform a much faster speed of capital structure adjustment comparing with non-credit firms.%银行授信可以通过缓解企业融资约束来降低企业的资本结构调整成本,从而有效提高资本结构的动态调整速度。但同时,企业能否获得银行授信,受到公司规模、投资机会等因素的影响,具有明显的样本选择性。因此,本文基于中国上市公司2001—2011年数据,在控制了授信的样本选择偏误的条件下,得到以下可信的证据:获得授信的公司表现出较快的调整速度,而不控制样本选择偏误的普通动态面板方法会使得估计有偏。本文不仅为资本结构的动态权衡理论提供了支持,同时也突出了在分组回归中控制样本选择偏误的重要性。

  10. AC1 Wing

    Adrian DOBRE

    2010-03-01

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

  11. AC1 Wing

    Adrian DOBRE

    2010-01-01

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

  12. Adjustments and Depression

    Full Text Available ... adjustment and depression Adjustment to paralysis is a process of changing one's thoughts and feelings and is ... stem cell research? What is the clinical trials process? Get support Ask us anything Get a peer ...

  13. Adjustments and Depression

    Full Text Available ... depression and adjustment to my SCI? How do I deal with depression and adjustment to my SCI? ☷ ▾ ... following an SCI? What are the secondary conditions? I have no health insurance, what are my options? ...

  14. Annual Adjustment Factors

    Department of Housing and Urban Development — The Department of Housing and Urban Development establishes the rent adjustment factors - called Annual Adjustment Factors (AAFs) - on the basis of Consumer Price...

  15. Adjustments and Depression

    Full Text Available ... course an adjustment period as you navigate your new normal. The most important point to remember is ... to rebuild one's identity and to find a new balance in relationships. The stages of adjustment can ...

  16. Touch Screen based Speed Control of Single Phase Induction Motor

    S. Mallika; W. Razia Sultana; Sarat Kumar Sahoo*

    2010-01-01

    This paper gives a brief idea of touch screen technology and its interfacing with a controller to control the speed of single phase induction motor. Here touch screen technology and Programmable System on Chip (PSOC) microcontroller concept is utilized which is less spaceconsumption and easy to design. The aim of this paper is to have remote sensing and speed control of an AC motor.

  17. On-Chip AC self-test controller

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

    2009-09-29

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

  18. Harmonic Calculation Software for Industrial Applications with Adjustable Speed Drives

    Asiminoaei, Lucian; Hansen, S.; Blaabjerg, Frede

    2005-01-01

    This paper describes the evaluation of a new harmonic software. By using a combination of a pre-stored database and new interpolation techniques the software can very fast provide the harmonic data on real applications. The harmonic results obtained with this software have acceptable precision even...... with limited input data. The evaluation concludes here that this approach is very practical compared to other advanced harmonic analysis methods. The results are supported by comparisons of calculations and measurements given in an industrial application....

  19. Jump Testing and the Speed of Market Adjustment

    Rasmussen, Torben B.

    Asymptotic properties of jump tests rely on the property that any jump occurs within a single time interval no matter what the observation frequency is. Market microstructure effects in relation to news-induced revaluation of the underlying variable is likely to make this an unrealistic assumption...

  20. Harmonic Calculation Toolbox in Industry Application for Adjustable Speed Drive

    Asiminoaei, Lucian; Blaabjerg, Frede; Hansen, Steffan

    2004-01-01

    Previous to electrical installation of large power non-linear loads, a comprehensive design-study is often required in order to determine if the overall installation complies with international regulations in respect to harmonics. Current THD voltage distortion and power factor are just few...

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

    Swanson, Robert R.

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

  2. Design of a Temperature Sensitive Voltage Regulator for AC Load using RTD

    Tasnuva Chowdhury,

    2010-12-01

    Full Text Available Voltage regulation of an electrical load has always been a necessity with the variation of atmospheric temperature. Human body undergoes troubles and sufferings when there is a certain change arises in the surrounding temperature and he or she might not be able to cope up with the sudden environmental change. To make life easier and better adjusted to the natural temperature change, a temperature sensitive voltage regulator have been designed and implemented in this work. Here a temperature sensor called Resistor Temperature Detector (RTD is used for temperature sensing purpose which delivers its output to the input of a voltage controller circuit and can subsequently control the speed of any light AC electrical load according to the variable temperature. In our project , the RTD was able to take the reading from 26oC to 38oC accurately. Moreover, the room temperature is also made visible by two 7-segment display. The circuit is synchronized and tested with the cheapest AC load (bulb availablein the market.

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

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

  4. ac bidirectional motor controller

    Schreiner, K.

    1988-01-01

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

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

    Venkatesan Jamuna

    2009-01-01

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

  6. Repatriation Adjustment: Literature Review

    Gamze Arman

    2009-12-01

    Full Text Available Expatriation is a widely studied area of research in work and organizational psychology. After expatriates accomplish their missions in host countries, they return to their countries and this process is called repatriation. Adjustment constitutes a crucial part in repatriation research. In the present literature review, research about repatriation adjustment was reviewed with the aim of defining the whole picture in this phenomenon. Present research was classified on the basis of a theoretical model of repatriation adjustment. Basic frame consisted of antecedents, adjustment, outcomes as main variables and personal characteristics/coping strategies and organizational strategies as moderating variables.

  7. Theory of adaptive adjustment

    Weihong Huang

    2000-01-01

    Full Text Available Conventional adaptive expectation as a mechanism of stabilizing an unstable economic process is reexamined through a generalization to an adaptive adjustment framework. The generic structures of equilibria that can be stabilized through an adaptive adjustment mechanism are identified. The generalization can be applied to a broad class of discrete economic processes where the variables interested can be adjusted or controlled directly by economic agents such as in cobweb dynamics, Cournot games, Oligopoly markets, tatonnement price adjustment, tariff games, population control through immigration etc.

  8. AC/RF Superconductivity

    Ciovati, Gianluigi [JLAB

    2015-02-01

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

  9. AC/RF Superconductivity

    Ciovati, G.

    2015-01-01

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

  10. SoC-Based Dynamic Power Sharing Method with AC-Bus Voltage Restoration for Microgrid Applications

    Lu, Xiaonan; Sun, Kai; Guerrero, Josep M.; Huang, Lipei

    shared in the energy storage system. The relationship between the droop coefficient and SoC are studied deeply and the small signal model is developed to verify the stability of the control system. It is found that the active power sharing speed becomes faster with higher exponent of SoC. At the same...... time, in order to restore the AC-bus voltage, secondary control is employed to eliminate the deviations of the voltage frequency and amplitude caused by the droop control, with the droop coefficients adjusting according to the SoCs. The model of the secondary control scheme for SoC-based droop method...... is developed and its stability is discussed. The theoretical analysis is demonstrated by both simulation and experimental results....

  11. The Hardware Design of Parameter-Adjustable FIR Filter System

    Guosheng Xu

    2013-01-01

    This design using FPGA parallel architecture, high computing speed and high-speed reliability of USB2.0 interface, designed an FPGA + USB2.0 + computer FIR digital filter system, organically combining the speed of FPGA and flexibility of Computer through USB2.0 bus. The results demonstrated that the coefficients configuring of the system is easy, which can adjust the filter coefficients flexibly according to the actual demand, that it can effectively filter out the noise signals.

  12. ADJUSTABLE CHIP HOLDER

    2009-01-01

    An adjustable microchip holder for holding a microchip is provided having a plurality of displaceable interconnection pads for connecting the connection holes of a microchip with one or more external devices or equipment. The adjustable microchip holder can fit different sizes of microchips with ...

  13. Speed Regulator for Permanent Magnet DC Boring Machine

    2000-01-01

    In this paper a variable-speed system for a loaded permanent magnet direct current boring machine (PMDCBM) is described in details. The voltage adjustment of PMDCBM is accomplished by means of solid state switch with a high gain Darlington transistor. The device designed possesses good variable speed characteristic and Iow loss at low speed. The speed can be regulated automatically to hold at an ideal value according to the load.

  14. Speed controller for an alternating - current motor

    A controller for a multi-phase ac motor that is subject to a large inertial load, e.g. an induction motor driving a heavy spinning rotor of a neutron chopper that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal Esub(L) having a meandering line frequency, includes a sensor which provides a feedback pulse train representative of the actual speed of the motor which is compared (by counting clock pulses between feedback pulses) with a reference clock signal in a computing unit to provide a motor control signal Esub(c). The motor control signal is a weighted linear sum of a speed error signal, a phase error signal, and a drift error signal, the magnitudes of which are recalculated and updated with each revolution of the motor shaft. The speed error signal is constant for large speed errors but highly sensitive to small speed errors. The stator windings of the motor are driven by variable-frequency power amplifiers which are controlled by the motor control signal Esub(c) via PROMs which store digital representations of sine and cosine waveforms in quadrature. (author)

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

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

  16. Hermetisk AC-Krets

    Hirsch, Carl; Smirnoff, Alexander

    2007-01-01

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

  17. Macroeconomic Situations and Policy Adjustments in China

    Dongjun Mao

    2009-01-01

    China has achieved wholly rapid growth, with economic reform and opening-up, since 1978. But the macro-economy is instable and showing prosperity and inflation, and Recession and deflation repeatedly with many times. Excessive fluctuations in the economy are due to macroeconomic policies’ amendments and adjustments, too loose or tight. Economic growth speeds up with macroeconomic fluctuations slowing down in recent years. Improvements in macroeconomic policies have played an important role. 2...

  18. Cascade Speed Control Of Dc Motor

    Anagha, Ranjith K; Anand C.P; Rahul Das; Anusha A.S

    2014-01-01

    Abstract: This paper presents a MATLAB aided Cascade designed controller to control and monitor the DC motor speed. First, design the driver circuit of the DC motor and use the microcontroller PIC16F877A to collect the feedback signals from the current sensor and optical encoder. The measured speed and current are serially transmitted to PC using RS232. By the MATLAB aided cascade controller, where inner loop is the current loop and outer loop is the speed loop, the parameters are adjusted to...

  19. Family Adjustment to Aphasia

    ... Public / Speech, Language and Swallowing / Disorders and Diseases Family Adjustment to Aphasia Richard S. was a senior manager ... It also presents a great challenge to the family. There may be tension among family members and ...

  20. Adjustments and Depression

    Full Text Available ... identity and to find a new balance in relationships. The stages of adjustment can include grieving, taking ... treatment options. Related pages What is a complete vs incomplete injury? What emergency procedures occur following an ...

  1. Adjustments and Depression

    Full Text Available ... thoughts and feelings and is something that takes time. The goal of adjusting is to rebuild one's ... updates about our impact > Get the Reeve newsletter International support > Pages in other languages Made with ♡ in ...

  2. Adjustments and Depression

    Full Text Available ... rebuild one's identity and to find a new balance in relationships. The stages of adjustment can include ... a peer mentor Advocate for change Fundraise with Team Reeve Champions Committee Volunteering About Us Our story ...

  3. KVA: Capital Valuation Adjustment

    Andrew Green; Chris Kenyon

    2014-01-01

    Credit (CVA), Debit (DVA) and Funding Valuation Adjustments (FVA) are now familiar valuation adjustments made to the value of a portfolio of derivatives to account for credit risks and funding costs. However, recent changes in the regulatory regime and the increases in regulatory capital requirements has led many banks to include the cost of capital in derivative pricing. This paper formalises the addition of cost of capital by extending the Burgard-Kjaer (2013) semi-replication approach to C...

  4. Improved Design Methods for Robust Single- and Three-Phase ac-dc-ac Power Converters

    Qin, Zian

    proposed new active power decoupling method, the ripple power in the converter can be compensated in a more efficient and more compact way. Then, Chapter 5 changes the scope of the thesis to three-phase converters, and the nine-switch converter, as a reduced switch version of two three-phase full......-bridges connected back-to-back, is studied. Application criteria of the nine-switch converter are investigated for reducing the relatively high stress introduced by the less number of switches. In Chapter 6 a rotating speed controller design method is proposed for improving the thermal loading of the three...... to users. Their performances including cost, efficiency, reliability, and so on, therefore are more important concerns than they were. The objective of this thesis is to study and propose advanced design methods for robust ac-dc-ac converters, which are widely used interfaces in energy conversion...

  5. High performance AC drives

    Ahmad, Mukhtar

    2010-01-01

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

  6. Superconducting ac cable

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

  7. Speeding or not speeding? When subjective assessment of safe, pleasurable and risky speeds determines speeding behaviour

    Florent Lheureux

    2012-01-01

    Full Text Available It is hypothesized that in a given situation speeding behaviour is determined by three subjective speed assessments: the speed perceived as the riskiest, the speed perceived as the safest, and the speed perceived as the most pleasurable. Specifically, if these assessments are high, drivers are expected to circulate faster. Such speed perceptions are also viewed as influenced by attitudes towards speed and speed limits. 177 car drivers, included 102 men and 75 women between 18 and 72 years (M = 43, SD = 21 and with a mean driving experience of 22 years (SD = 19, answered to a questionnaire about their attitudes towards speed and speed limits, the speeds they considered as the riskiest, the safest, and the most pleasurable in three different contexts, as well as their usual speed. Data analyses (ANOVA and path analyses confirmed the influence of the three types of speed assessment on the usual speed and that the influence of attitudes on this behaviour is mediated by these three assessments. Results suggest that not only a change in attitudes and beliefs is desirable, but a concrete specification (e.g., 100 Km/h of speeds perceived as safe, pleasurable and risky is also needed in order to reduce speeding behaviour.

  8. Measures for speed management.

    2009-01-01

    Measures for speed management are essential for limiting the negative effects of driving too fast and at inappropriate speeds. To begin with, safe and credible speed limits need to be determined. Dynamic and variable speed limits that take into account the current circumstances, such as weather cond

  9. Touch Screen based Speed Control of Single Phase Induction Motor

    S. Mallika

    2010-12-01

    Full Text Available This paper gives a brief idea of touch screen technology and its interfacing with a controller to control the speed of single phase induction motor. Here touch screen technology and Programmable System on Chip (PSOC microcontroller concept is utilized which is less spaceconsumption and easy to design. The aim of this paper is to have remote sensing and speed control of an AC motor.

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

    M. Cirrincione

    2005-03-01

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

  11. Sustainable urban regime adjustments

    Quitzau, Maj-Britt; Jensen, Jens Stissing; Elle, Morten;

    2013-01-01

    The endogenous agency that urban governments increasingly portray by making conscious and planned efforts to adjust the regimes they operate within is currently not well captured in transition studies. There is a need to acknowledge the ambiguity of regime enactment at the urban scale. This direc...

  12. Auto Adjusting Astronomical Telescope

    Rohit R. Ghalsasi; Prof. N. D. Dhoot

    2014-01-01

    Astronomical telescope is powerful and basic tool for star or celestial observation. Here we proposed integrated system using Raspberry Pi for auto adjusting astronomical telescope. This integrated circuit helps to control stellar monitoring, stellar targeting, and tracking functions of telescope. Astro compass gives the direction of the celestial objects.

  13. Adjustments and Depression

    Full Text Available ... 7309 ☰ Living with Paralysis Get Support Get Involved Research Events Blog & Forum About Us Donate Living with Paralysis > Newly paralyzed > How do I deal with depression and adjustment to my SCI? How do I deal with depression and ...

  14. Auto Adjusting Astronomical Telescope

    Rohit R. Ghalsasi

    2014-04-01

    Full Text Available Astronomical telescope is powerful and basic tool for star or celestial observation. Here we proposed integrated system using Raspberry Pi for auto adjusting astronomical telescope. This integrated circuit helps to control stellar monitoring, stellar targeting, and tracking functions of telescope. Astro compass gives the direction of the celestial objects.

  15. Kinematic synthesis of adjustable robotic mechanisms

    Chuenchom, Thatchai

    1993-01-01

    Conventional hard automation, such as a linkage-based or a cam-driven system, provides high speed capability and repeatability but not the flexibility required in many industrial applications. The conventional mechanisms, that are typically single-degree-of-freedom systems, are being increasingly replaced by multi-degree-of-freedom multi-actuators driven by logic controllers. Although this new trend in sophistication provides greatly enhanced flexibility, there are many instances where the flexibility needs are exaggerated and the associated complexity is unnecessary. Traditional mechanism-based hard automation, on the other hand, neither can fulfill multi-task requirements nor are cost-effective mainly due to lack of methods and tools to design-in flexibility. This dissertation attempts to bridge this technological gap by developing Adjustable Robotic Mechanisms (ARM's) or 'programmable mechanisms' as a middle ground between high speed hard automation and expensive serial jointed-arm robots. This research introduces the concept of adjustable robotic mechanisms towards cost-effective manufacturing automation. A generalized analytical synthesis technique has been developed to support the computational design of ARM's that lays the theoretical foundation for synthesis of adjustable mechanisms. The synthesis method developed in this dissertation, called generalized adjustable dyad and triad synthesis, advances the well-known Burmester theory in kinematics to a new level. While this method provides planar solutions, a novel patented scheme is utilized for converting prescribed three-dimensional motion specifications into sets of planar projections. This provides an analytical and a computational tool for designing adjustable mechanisms that satisfy multiple sets of three-dimensional motion specifications. Several design issues were addressed, including adjustable parameter identification, branching defect, and mechanical errors. An efficient mathematical scheme for

  16. The Design of Sport Bicycle Speed Odometer

    Dongbing Liu

    2013-04-01

    Full Text Available As bicycle sport equipment, a sport bike needs a speed and distance measuring device, due to the characteristic of road cycling, thereby mastering the state of motion. According to external conditions such as temperature, wind speed, the bike can make the appropriate adjustment to achieve the best movement effect. The bicycle speed odometer is a major accessibility tool that satisfies with needs of the people with fast development. This study elaborated a bike speed odometer design based on Hall element, taking AT89C52 single chip as the core, measuring speed with A44E Hall sensor, to finish the bike mileage/speed measurement and statistics by displaying bike mileage and speed in real time. By using the Hall elements, the hardware of speed odometer input the number of pulse of per circle into the single-chip computer system. Then the signal processed by the single-chip computer displays. The software is programmed with assembly language and modular design idea. The design of the hardware circuit is simple and the subroutine has universal property, which fully meet the design requirements and possess a wide range of application and dissemination value.

  17. Ac Hybrid Charge Controller

    Shalini S. Durgam

    2015-03-01

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

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

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

    2012-06-05

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

  19. Control of Adjustable Compliant Actuators

    Berno J.E. Misgeld

    2014-05-01

    Full Text Available Adjustable compliance or variable stiffness actuators comprise an additional element to elastically decouple the actuator from the load and are increasingly applied to human-centered robotic systems. The advantages of such actuators are of paramount importance in rehabilitation robotics, where requirements demand safe interaction between the therapy system and the patient. Compliant actuator systems enable the minimization of large contact forces arising, for example, from muscular spasticity and have the ability to periodically store and release energy in cyclic movements. In order to overcome the loss of bandwidth introduced by the elastic element and to guarantee a higher range in force/torque generation, new actuator designs consider variable or nonlinear stiffness elements, respectively. These components cannot only be adapted to the walking speed or the patient condition, but also entail additional challenges for feedback control. This paper introduces a novel design method for an impedance-based controller that fulfills the control objectives and compares the performance and robustness to a classical cascaded control approach. The new procedure is developed using a non-standard positive-real Η2 controller design and is applied to a loop-shaping approach. Robust norm optimal controllers are designed with regard to the passivity of the actuator load-impedance transfer function and the servo control problem. Classical cascaded and positive-real Η2 controller designs are validated and compared in simulations and in a test bench using a passive elastic element of varying stiffness.

  20. Exploration adjustment by ant colonies.

    Doran, Carolina; Stumpe, Martin C; Sendova-Franks, Ana; Franks, Nigel R

    2016-01-01

    How do animals in groups organize their work? Division of labour, i.e. the process by which individuals within a group choose which tasks to perform, has been extensively studied in social insects. Variability among individuals within a colony seems to underpin both the decision over which tasks to perform and the amount of effort to invest in a task. Studies have focused mainly on discrete tasks, i.e. tasks with a recognizable end. Here, we study the distribution of effort in nest seeking, in the absence of new nest sites. Hence, this task is open-ended and individuals have to decide when to stop searching, even though the task has not been completed. We show that collective search effort declines when colonies inhabit better homes, as a consequence of a reduction in the number of bouts (exploratory events). Furthermore, we show an increase in bout exploration time and a decrease in bout instantaneous speed for colonies inhabiting better homes. The effect of treatment on bout effort is very small; however, we suggest that the organization of work performed within nest searching is achieved both by a process of self-selection of the most hard-working ants and individual effort adjustment. PMID:26909180

  1. AcEST: BP920072 [AcEST

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

  2. Credit Valuation Adjustment

    Hoffman, Frederick

    2011-01-01

    Credit risk has become a topical issue since the 2007 Credit Crisis, particularly for its impact on the valuation of OTC derivatives. This becomes critical when the credit risk of entities involved in a contract either as underlying or counterparty become highly correlated as is the case during macroeconomic shocks. It impacts the valuation of such contracts through an additional term, the credit valuation adjustment (CVA). This can become large with such correlation. This thesis outlines the...

  3. Adjustable Autonomy Testbed

    Malin, Jane T.; Schrenkenghost, Debra K.

    2001-01-01

    The Adjustable Autonomy Testbed (AAT) is a simulation-based testbed located in the Intelligent Systems Laboratory in the Automation, Robotics and Simulation Division at NASA Johnson Space Center. The purpose of the testbed is to support evaluation and validation of prototypes of adjustable autonomous agent software for control and fault management for complex systems. The AA T project has developed prototype adjustable autonomous agent software and human interfaces for cooperative fault management. This software builds on current autonomous agent technology by altering the architecture, components and interfaces for effective teamwork between autonomous systems and human experts. Autonomous agents include a planner, flexible executive, low level control and deductive model-based fault isolation. Adjustable autonomy is intended to increase the flexibility and effectiveness of fault management with an autonomous system. The test domain for this work is control of advanced life support systems for habitats for planetary exploration. The CONFIG hybrid discrete event simulation environment provides flexible and dynamically reconfigurable models of the behavior of components and fluids in the life support systems. Both discrete event and continuous (discrete time) simulation are supported, and flows and pressures are computed globally. This provides fast dynamic simulations of interacting hardware systems in closed loops that can be reconfigured during operations scenarios, producing complex cascading effects of operations and failures. Current object-oriented model libraries support modeling of fluid systems, and models have been developed of physico-chemical and biological subsystems for processing advanced life support gases. In FY01, water recovery system models will be developed.

  4. Physicians' adjustment to retirement.

    Virshup, B; Coombs, R H

    1993-01-01

    We address the questions, How do physicians adjust to and enjoy their retirement? What factors contribute to the well-being of retired physicians? A 60-item questionnaire mailed to 238 retired physicians in Los Angeles County with a 41.6% response rate assessed health, standard of living, relationships, activities, emotional difficulties, and general enjoyment. Health often improved after retirement, as did relationships with spouses and children. Standard of living was comfortable or better ...

  5. SPEED COMPLIANCE IN FREEWAY VARIABLE SPEED LIMIT SYSTEM – CASE STUDY OF THE PRAGUE CITY RING

    Michał MATOWICKI

    2016-03-01

    Full Text Available Many previous studies have confirmed the strong relationship between speed compliance and the frequency and severity of traffic accidents. Variable speed limit (VSL system as a measure to improve traffic safety enables the freeway system to change its posted speed limit based on various traffic and environmental conditions. Such system helps drivers to recognize the upcoming events, to adjust their driving style and in such way to address speed variation of the traffic flow. This is called speed harmonization. Although many studies researching the effect of VSL system on the traffic stream can be found, there are only few addressing its influence on the drivers behavior, particularly focusing on their tolerance limit and compliance, which has crucial meaning for future design of controlling algorithms. This study was prepared to inspect this grey area by studying the data from the VSL system at Prague city ring, describing the influence of the highway management system and its influence on drivers.

  6. A speed auto-adaptable system for high speed inspection of rail-track defects

    Ge, Jia; Luo, Yunhan; Zhang, Jun; Guo, Long; Sun, Liang; Chen, Zhe

    2012-11-01

    High quality images play a key role in inspecting surface defect of rail track. However, image distortion is frequently occurred in traditional detection systems in which exposure frequency of camera are fixed as constant. The system studied in this paper improves traditional systems by combining a speed auto-adaptable (SAA) system, to adjust proper exposure frequency and uniform image quality all the time according to vehicle riding speed. The system mainly consists of a high-speed external controlled camera, a rotary encoder and a signal processing card, with this system, performance in avoiding image distortion both in laboratory test and practical application can be achieved with minimum detection precision of 0.2 mm at relative low speed and theoretically maximum detection speed of approximate 489 km/h.

  7. Online optimal flux-weakening control of permanent-magnet brushless AC drives

    Zhu, Z.Q.; Chen, Y. S.; Howe, D.

    2000-01-01

    An enhanced online optimal control strategy, which maximizes the flux-weakening performance of a brushless AC motor, is described, and applied to motors having different rotor topologies: interior (radial or circumferential), inset, and surface-mounted magnet. It enables the maximum inherent power capability of a brushless AC motor to be achieved independent of any variation in its parameters, and facilitates maximum efficiency over the entire speed range. It also results in good transient dy...

  8. Adjustment Criterion and Algorithm in Adjustment Model with Uncertain

    SONG Yingchun

    2015-02-01

    Full Text Available Uncertainty often exists in the process of obtaining measurement data, which affects the reliability of parameter estimation. This paper establishes a new adjustment model in which uncertainty is incorporated into the function model as a parameter. A new adjustment criterion and its iterative algorithm are given based on uncertainty propagation law in the residual error, in which the maximum possible uncertainty is minimized. This paper also analyzes, with examples, the different adjustment criteria and features of optimal solutions about the least-squares adjustment, the uncertainty adjustment and total least-squares adjustment. Existing error theory is extended with new observational data processing method about uncertainty.

  9. System and method for motor speed estimation of an electric motor

    Lu, Bin; Yan, Ting; Luebke, Charles John; Sharma, Santosh Kumar

    2012-06-19

    A system and method for a motor management system includes a computer readable storage medium and a processing unit. The processing unit configured to determine a voltage value of a voltage input to an alternating current (AC) motor, determine a frequency value of at least one of a voltage input and a current input to the AC motor, determine a load value from the AC motor, and access a set of motor nameplate data, where the set of motor nameplate data includes a rated power, a rated speed, a rated frequency, and a rated voltage of the AC motor. The processing unit is also configured to estimate a motor speed based on the voltage value, the frequency value, the load value, and the set of nameplate data and also store the motor speed on the computer readable storage medium.

  10. AcEST: BP920905 [AcEST

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

  11. AcEST: DK950147 [AcEST

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

  12. AcEST: DK959344 [AcEST

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

  13. AcEST: DK949716 [AcEST

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

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

    Peak, S. C.

    1982-01-01

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

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

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

    1992-08-01

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

  16. Speed-up electric railways. Denki tetsudo no kosokuka

    Yasukawa, S.; Ito, J. (Railway Technical Research Institute, Tokyo (Japan))

    1993-04-20

    Explanation was made of speed heightening tendency of electric rail transport in Japan and Europe. The electric rail transport can transport a large quantity with a high safety and largely contribute particularly to the energy saving and solution of environmental problems. Introduction was made of Japanese superexpress lines, French TGV network, and German and Italian high speed railroads. DC motor has been conventionally used to strengthen the output as required by the speed heightening. Because the commutator and dynamic braking resistor are limited in size enlarging and weight increasing as required by a further speed heightening, the DC motor is being replaced by the AC motor or synchronous motor without commutators for the driving. For the coach weight lightening, design is made by lightening the bogie weight, compatibly with maintaining the running stability, and using the aluminum alloy for the body. The air resistance is proportional to the speed squared and therefore, particularly important for the high speed train. Progress is made in taking measures against the noise and vibration (due to dislocation, spark and aerodynamic force) under a stable power collecting performance through pantograph hardly coming off the overhead line. Pertaining to the ground facilities to satisfy the speed heightening, also mentioned were AC generation system which can supply a large electric energy, overhead wiring system, and ATC and other signal maintaining system. 31 refs., 10 figs., 2 tabs.

  17. Jordan Adjusted Human Development

    Ababsa, Myriam

    2014-01-01

    Jordan Human Development Index (HDI) and Adjusted Human Development Index (IHDI) In 1990, the United Nations Development Programme designed a Human Development Index composed of life expectancy at birth, level of education and gross domestic product (GDP) per capita. In 2011, the UNDP ranked Jordan 95th out of 187 countries with a human development index of 0.698, up from 0.591 in 1990, making it the leading medium-range country for human development (fig. VIII.1). In 2010, the inequality adj...

  18. Continuously adjustable Pulfrich spectacles

    Jacobs, Ken; Karpf, Ron

    2011-03-01

    A number of Pulfrich 3-D movies and TV shows have been produced, but the standard implementation has inherent drawbacks. The movie and TV industries have correctly concluded that the standard Pulfrich 3-D implementation is not a useful 3-D technique. Continuously Adjustable Pulfrich Spectacles (CAPS) is a new implementation of the Pulfrich effect that allows any scene containing movement in a standard 2-D movie, which are most scenes, to be optionally viewed in 3-D using inexpensive viewing specs. Recent scientific results in the fields of human perception, optoelectronics, video compression and video format conversion are translated into a new implementation of Pulfrich 3- D. CAPS uses these results to continuously adjust to the movie so that the viewing spectacles always conform to the optical density that optimizes the Pulfrich stereoscopic illusion. CAPS instantly provides 3-D immersion to any moving scene in any 2-D movie. Without the glasses, the movie will appear as a normal 2-D image. CAPS work on any viewing device, and with any distribution medium. CAPS is appropriate for viewing Internet streamed movies in 3-D.

  19. Speed and income

    Fosgerau, Mogens

    2005-01-01

    The relationship between speed and income is established in a microeconomic model focusing on the trade-off between travel time and the risk of receiving a penalty for exceeding the speed limit. This is used to determine when a rational driver will choose to exceed the speed limit. The relationship...... between speed and income is found again in the empirical analysis of a cross-sectional dataset comprising 60,000 observations of car trips. This is used to perform regressions of speed on income, distance travelled, and a number of controls. The results are clearly statistically significant and indicate...... an average income elasticity of speed of 0.02; it is smaller at short distances and about twice as large at the longest distance investigated of 200 km....

  20. The Design of Fiscal Adjustments

    Alesina, Alberto Francesco; Ardagna, Silvia

    2013-01-01

    This paper offers three results. First, in line with the previous literature, we confirm that fiscal adjustments based mostly on the spending side are less likely to be reversed. Second, spending based fiscal adjustments have caused smaller recessions than tax based fiscal adjustments. Finally, certain combinations of policies have made it possible for spending based fiscal adjustments to be associated with growth in the economy even on impact rather than with a recession. Thus, expansionary ...

  1. Modelling ac ripple currents in HTS coated conductors

    Xu, Zhihan; Grilli, Francesco

    2015-10-01

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

  2. SPEED CONTROL OF DC MOTOR WITH PIC 16F877

    ÇOLAK, İlhami; Ramazan BAYINDIR

    2005-01-01

    In this study, a PI controlled separately excited direct current (DC) motor speed has been controlled using PIC 16F877 controller. In the PIC 16F877 programming as a PI controller, the speed of the motor is expected to follow the reference speed. Speed of the motor is measured by a tacho generator and then, the voltage applied to the motor is adjusted by a semiconductor power switch using pulse width modulation (PWM) technique. Drive circuit was tested with 0.9 kW DC motor. Experimental resul...

  3. SPEED CONTROL OF DC MOTOR WITH PIC 16F877

    İlhami ÇOLAK

    2005-02-01

    Full Text Available In this study, a PI controlled separately excited direct current (DC motor speed has been controlled using PIC 16F877 controller. In the PIC 16F877 programming as a PI controller, the speed of the motor is expected to follow the reference speed. Speed of the motor is measured by a tacho generator and then, the voltage applied to the motor is adjusted by a semiconductor power switch using pulse width modulation (PWM technique. Drive circuit was tested with 0.9 kW DC motor. Experimental results show that the drive circuit developed is very simple, useful, sensible, economical and flexible to apply for different applications.

  4. Technical Document for Price Adjustment

    Zheng Tian; Mulugeta Kahsai; Randall Jackson

    2014-01-01

    This document presents the basis for the price adjustment mechanisms in a time series IO model. The essentials of the price adjustment and price change propagation algorithms are presented, along with a matrix permutation algorithm that facilitates the implementation of the price adjustment mechanism. The Matlab function is provided.

  5. 46 CFR 154.1864 - Vessel speed within speed reduction.

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Vessel speed within speed reduction. 154.1864 Section... Vessel speed within speed reduction. The master shall ensure that the speed of the vessel is not greater than the posted speed reduction....

  6. Metric adjusted skew information

    Hansen, Frank

    2008-01-01

    We extend the concept of Wigner-Yanase-Dyson skew information to something we call "metric adjusted skew information" (of a state with respect to a conserved observable). This "skew information" is intended to be a non-negative quantity bounded by the variance (of an observable in a state) that...... vanishes for observables commuting with the state. We show that the skew information is a convex function on the manifold of states. It also satisfies other requirements, proposed by Wigner and Yanase, for an effective measure-of-information content of a state relative to a conserved observable. We...... establish a connection between the geometrical formulation of quantum statistics as proposed by Chentsov and Morozova and measures of quantum information as introduced by Wigner and Yanase and extended in this article. We show that the set of normalized Morozova-Chentsov functions describing the possible...

  7. Adjusting to the Emergent

    Revsbæk, Line

    In her doctoral thesis Line Revsbaek explores newcomer innovation related to organizational entry processes in a changing organization. She introduces process philosophy and complexity theory to research on organizational socialization and newcomer innovation. The study challenges assumptions...... in standardized induction programs where newcomers are cast in roles as insecure novices needing to be “taught the ropes” of the organizational culture. Linked with this, it is suggested that the prevailing dichotomy of ‘newcomer assimilation’ versus ‘organizational accommodation’ is replaced with a notion...... of ‘adjusting to the emergent’. Newcomer innovation is portrayed as carrying a variety of possible significations, such as unintentional innovation effects of newcomer’s proactive self-socializing behavior; an inspirational basis for designing innovation-generating employee induction; ‘resonant instances...

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

    Abdul Sattar Larik

    2011-01-01

    Full Text Available AC voltage controllers are used to vary the output ac voltage from a fixed ac input source. They are also commonly called ac voltage regulators or ac choppers. The output voltage is either controlled by PAC (Phase Angle Control method or on-off control method. Due to various advantages of ac voltage controllers, such as high efficiency, simplicity, low cost and ability to control large amount of power they efficiently control the speed of ac motors, light dimming and industrial heating, etc. These converters are variable structure systems and generate harmonics during the operation which will affect the power quality when connected to system network. During the last couple of years, a number of new semiconductor devices and various power electronic converters has been introduced. Accordingly the subject of harmonics and its problems are of great concern to power industry and customers. In this research work, initially the simulation models of single phase unidirectional and bidirectional ac voltage controllers were developed by using MATLAB software. The harmonics of these models are investigated by simulation. In the end, the harmonics were also analyzed experimentally. The simulated as well as experimental results are presented.

  9. Adjustment Behaviours of Dividend Payouts in G7 Countries: A Different Look

    Joshua Seungwook Bahng

    2011-10-01

    Full Text Available The topic of the dividend adjustment behaviours of firms in G7 countries was analysed in this study. After dividing the entire sample of firms into countries and separating listed, delisted, and unlisted firms by their listing type, we investigated the question using quantile regressions. Our analyses provided the following results. First, payout ratios showed decreasing tendencies irrespective of both country origin and listing types. Second, the speeds of dividend adjustment in Japan and Italy were estimated to be the fastest by quantile, whereas that of Canadian firms was estimated to be the slowest. Third, when the same issue was examined for listing types, unlisted firms showed the fastest speed of adjustment. In general, the estimated curves for both the speed of adjustment and the required time for partial adjustment were found to be cross-sectionally unstable and nonlinear with respect to dividend levels.

  10. More Than Just Speed

    2011-01-01

    The 1,318-km Beijing-Shanghai High-Speed Railway will finally come into operation at the end of June.Since construction began three years ago,the speedy railway has grabbed worldwide attention because of its design as the world’s longest and fastesthigh-speed rail line utilizing the most advanced technology.

  11. Speed enforcement in Norway

    Elvik, Rune

    2015-01-01

    This paper probes the relationship between changes in the risk of apprehension for speeding in Norway and changes in the amount of speeding. The paper is based on a game-theoretic model of how the rate of violations and the amount of enforcement is determined by the interaction between drivers and...

  12. A Dynamic Flexible Partial-Adjustment Model of International Diffusion of the Internet

    Lee, Minkyu; Heshmati, Almas

    2006-01-01

    The paper introduces a dynamic, flexible partial-adjustment model and uses it to analyze the diffusion of Internet connectivity. It specifies and estimates desired levels of Internet diffusion and the speed at which countries achieve the target levels. The target levels and speed of adjustment are both country and time specific. Factors affecting Internet diffusion across countries are identified, and, using nonlinear least squares, the Gompertz growth model is generalized and estimated using...

  13. AcEST: DK955197 [AcEST

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

  14. AcEST: BP915640 [AcEST

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

  15. Adjustable drives boost nuclear plant reliability

    A new reactor recirculation control (RRC) adjustable-speed drive (ASD) and digital control system at the Washington Nuclear Plant 2 (WNP-2), Hanford, Wash., has improved plant reliability. Installed this year, the system also will lower plant maintenance costs and reduce personnel radiation doses during maintenance, since the new system has less equipment in high-radiation areas than its predecessor. Advances in power electronics have improved the reliability of adjustable-speed drives for large induction motors. Large ASDs have been used in gas, oil, and coal-fired plants since around 1984. Plants where these systems are installed have realized energy savings and operational improvements in precisely controlling process flow. They also have reduced motor maintenance by slowing the motors when full-power operation is not needed. WNP-2 is the first nuclear utility with a boiling-water reactor to change to digitally controlled reactor recirculation pumps. The new RRC system provides improved flow control and maneuverability, when operating the nuclear reactor at reduced power levels. It controls coolant flow through the reactor core to control power during normal operation. There are two pumps rated at 47,200 gallons per minute (gpm). Each is driven by a vertical, totally enclosed, air/water-cooled, three-phase induction motor. The motor is rated at 8,900 horsepower (hp) and 1,782 revolutions per minute (rpm) and is operated from a 6,600-volt, 60-hertz (Hz) electrical power supply. THe ASD and digital control system replaced a hydraulically operated flow control valve and analog control system for throttling pump output. The replacement also resulted in removing the low-frequency motor generator set used for startup and slow-speed operation. The flow control valve system required a shift from low to high frequency at minimum flow control valve position to prevent excess reactor power conditions from forming during pump shift. 6 refs., 2 figs

  16. Effectiveness of Motorcycle speed controlled by speed hump

    Pornsiri Urapa

    2014-09-01

    Full Text Available Speed humps are one of the traffic calming measures widely accepted to control vehicle speed in the local road. Humps standards from the western countries are designed mainly for the passenger car. This study, therefore, aims to reveal the effectiveness of speed hump to control the motorcycle speed. This study observes the free-flow speed of the riders at the total of 20 speed bumps and humps. They are 0.3-14.8 meter in width and 5-18 centimeter in height. The results reveal that the 85th percentile speeds reduce 15-65 percent when crossing the speed bumps and speed humps. Besides, this study develops the speed model to predict the motorcycle mean speed and 85th percentile speed. It is found that speed humps follow the ITE standard can control motorcycle crossing speeds to be 25-30 Kph which are suitable to travel on the local road.

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

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

  18. Delay Adjusted Incidence Infographic

    This Infographic shows the National Cancer Institute SEER Incidence Trends. The graphs show the Average Annual Percent Change (AAPC) 2002-2011. For Men, Thyroid: 5.3*,Liver & IBD: 3.6*, Melanoma: 2.3*, Kidney: 2.0*, Myeloma: 1.9*, Pancreas: 1.2*, Leukemia: 0.9*, Oral Cavity: 0.5, Non-Hodgkin Lymphoma: 0.3*, Esophagus: -0.1, Brain & ONS: -0.2*, Bladder: -0.6*, All Sites: -1.1*, Stomach: -1.7*, Larynx: -1.9*, Prostate: -2.1*, Lung & Bronchus: -2.4*, and Colon & Rectum: -3/0*. For Women, Thyroid: 5.8*, Liver & IBD: 2.9*, Myeloma: 1.8*, Kidney: 1.6*, Melanoma: 1.5, Corpus & Uterus: 1.3*, Pancreas: 1.1*, Leukemia: 0.6*, Brain & ONS: 0, Non-Hodgkin Lymphoma: -0.1, All Sites: -0.1, Breast: -0.3, Stomach: -0.7*, Oral Cavity: -0.7*, Bladder: -0.9*, Ovary: -0.9*, Lung & Bronchus: -1.0*, Cervix: -2.4*, and Colon & Rectum: -2.7*. * AAPC is significantly different from zero (p<.05). Rates were adjusted for reporting delay in the registry. www.cancer.gov Source: Special section of the Annual Report to the Nation on the Status of Cancer, 1975-2011.

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

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

    2008-01-01

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

  20. AcEST: BP920800 [AcEST

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

  1. AcEST: DK945549 [AcEST

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

  2. AcEST: BP917632 [AcEST

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

  3. AcEST: DK961189 [AcEST

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

  4. AcEST: DK946687 [AcEST

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

  5. AcEST: DK949372 [AcEST

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

  6. Proactive Adjustments of Response Strategies in the Stop-Signal Paradigm

    Verbruggen, Frederick; Logan, Gordon D.

    2009-01-01

    In the stop-signal paradigm, fast responses are harder to inhibit than slow responses, so subjects must balance speed is the go task with successful stopping in the stop task. In theory, subjects achieve this balance by adjusting response thresholds for the go task, making proactive adjustments in response to instructions that indicate that…

  7. Metric-adjusted skew information

    Liang, Cai; Hansen, Frank

    2010-01-01

    We give a truly elementary proof of the convexity of metric-adjusted skew information following an idea of Effros. We extend earlier results of weak forms of superadditivity to general metric-adjusted skew information. Recently, Luo and Zhang introduced the notion of semi-quantum states on a...... bipartite system and proved superadditivity of the Wigner-Yanase-Dyson skew informations for such states. We extend this result to the general metric-adjusted skew information. We finally show that a recently introduced extension to parameter values 1 < p = 2 of the WYD-information is a special case of...... (unbounded) metric-adjusted skew information....

  8. Adjustment computations spatial data analysis

    Ghilani, Charles D

    2011-01-01

    the complete guide to adjusting for measurement error-expanded and updated no measurement is ever exact. Adjustment Computations updates a classic, definitive text on surveying with the latest methodologies and tools for analyzing and adjusting errors with a focus on least squares adjustments, the most rigorous methodology available and the one on which accuracy standards for surveys are based. This extensively updated Fifth Edition shares new information on advances in modern software and GNSS-acquired data. Expanded sections offer a greater amount of computable problems and their worked solu

  9. Dissecting the PPP Puzzle: The Unconventional Roles of Nominal Exchange Rate and Price Adjustments

    Yin-wong Cheung; Lai, Kon S.; Michael Bergman

    2003-01-01

    The conventional view, as expounded by sticky-price models, is that price adjustment determines the PPP reversion rate. This study examines the mechanism by which PPP deviations are corrected. Nominal exchange rate adjustment, not price adjustment, is shown to be the key engine governing the speed of PPP convergence. Moreover, nominal exchange rates are found to converge much more slowly than prices. With the reversion being driven primarily by nominal exchange rates, real exchange rates also...

  10. Dissecting the PPP Puzzle: The Unconventional Roles of Nominal Exchange Rate and Price Adjustment

    Cheung, Yin-Wong; Lai, Kon S.; BERGMAN, MICHAEL

    2003-01-01

    The conventional view, as expounded by sticky-price models, is that price adjustment determines the PPP reversion rate. This study examines the mechanism by which PPP deviations are corrected. Nominal exchange rate adjustment, not price adjustment, is shown to be the key engine governing the speed of PPP convergence. Moreover, nominal exchange rates are found to converge much more slowly than prices. With the reversion being driven primarily by nominal exchange rates, real exchange rates also...

  11. Management Practices and Financial Performance of Agricultural Cooperatives: A Partial Adjustment Model

    Azzam, Azzeddine M.; Turner, Michael S.

    1991-01-01

    This paper uses the Nerlovian partial adjustment model to test the hypothesis that the rate of a cooperative's adjustment to a desired financial position is partially determined by its management practices. The results indicate that management practices that are board responsibilities are not contributing to the speed of adjustment in reaching the desired financial performance, which is the responsibility of the board of directors. But management, when independently pursuing management's resp...

  12. The adjustment of financial ratios in the presence of soft budget constraints: evidence from Bulgaria.

    Konings, Josef

    2004-01-01

    This paper is the first to study the behaviour of financial ratios in an emerging economy of Central Europe. Using the entire population of company accounts in Bulgaria we find that for the financial ratios we considered, adjustment towards a target takes place but the speed of adjustment is lower than that for Western companies reported in earlier studies. Also, we find the adjustment of financial ratios in Bulgaria to be far slower in firms characterized by soft budget constraints, a widesp...

  13. High-Speed Photography

    The applications of high-speed photography to a diverse set of subjects including inertial confinement fusion, laser surgical procedures, communications, automotive airbags, lightning etc. are briefly discussed. (AIP) copyright 1998 Society of Photo-Optical Instrumentation Engineers

  14. High-Speed Photography

    Paisley, D.L. [Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Schelev, M.Y. [General Physics Institute, Moscow (Russia)

    1998-08-01

    The applications of high-speed photography to a diverse set of subjects including inertial confinement fusion, laser surgical procedures, communications, automotive airbags, lightning etc. are briefly discussed. (AIP) {copyright} {ital 1998 Society of Photo-Optical Instrumentation Engineers.}

  15. Wind_Speeds_Master

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set included wind speeds for each subregion in the study (Georges Bank, Gulf of Maine, Southern New England, Middle Atlantic Bight) . The data came from...

  16. Speeding up Transportation

    2007-01-01

    @@ 2007 was an excellent year for the transportation industry, marked by high speed railway transportation, development of the national expressway network and launch of the Chang'e lunar probe satellite.

  17. High speed data acquisition

    A general introduction to high speed data acquisition system techniques in modern particle physics experiments is given. Examples are drawn from the SELEX(E78 1) high statistics charmed baryon production and decay experiment now taking data at Fermilab

  18. High speed data acquisition

    Cooper, P.S.

    1997-07-01

    A general introduction to high speed data acquisition system techniques in modern particle physics experiments is given. Examples are drawn from the SELEX(E78 1) high statistics charmed baryon production and decay experiment now taking data at Fermilab.

  19. Variable Speed Wind Turbine Based on Multiple Generators Drive-Train Configuration

    Deng, Fujin; Chen, Zhe

    2010-01-01

    A variable speed wind turbine is presented in this paper, where multiple permanent magnet synchronous generators (MPMSGs) drive-train configuration is employed in the wind turbine. A cascaded multilevel converter interface based on the MPMSGs is developed to synthesize a desired high ac sinusoidal output voltage, which could be directly connected to the grids. What is more, such arrangement has been made so that the output ac voltage having a selected phase angle difference among the stator w...

  20. Energy saving in ac generators

    Nola, F. J.

    1980-01-01

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

  1. Apuntes de Acústica

    Martín Domingo, Agustín

    2014-01-01

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

  2. SSTI Clark ACS Technology Demonstrations

    Freesland, Douglas

    1997-01-01

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

  3. High Speed Economy

    Vadim Dumitrascu; Roxana Arabela Dumitrascu

    2013-01-01

    The use of knowledge in business opens vast possibilities for the spectacular intensification of the rhythms of the processes of economic value creation. High speeds are a fundamental feature of the knowledge economy. The sources of high speeds in business are certain economic, technological and commercial processes with the nature of some positive feedbacks. What generates it is the organization of knowledge in the form of networks. The organizations competitiveness is marked by the ability ...

  4. Optimization of target speeds of high-speed railway trains for traction energy saving and transport efficiency improvement

    In the pursuit of higher operation speed at the passenger train services in China, the impacts of high-speed operation on energy consumption and transport efficiency are however not clearly identified. This research attempts to analyze the traction energy cost and transport operation time per 10,000 passenger-kilometers of high-speed railway (HSR) trains with a range of target speeds on certain HSR lines in China through a simulation approach. Having considered the effect of inter-stop transport distances, traction characteristics of HSR trains and gradients, curvatures, etc. of the rail lines, this study has deduced that the target speed of a HSR train for an inter-stop transport distance shorter than 100 km should be below 190 km/h from the perspectives of traction energy saving and transport efficiency improvement. Moreover, the study results also indicate that, unlike the actual HSR operation, the target speed should be dynamically adjusted according to the transport distances between stops if the transport capacity of the rail line is not extensively used. The exact target speed for each inter-stop transport distance shorter than 100 km should be further determined according to the traction characteristics of the train and the track geometry of the rail line. - Highlights: ► We simulate traction processes of different high-speed trains. ► We study trains' target speeds, energy costs and transport efficiencies. ► Short stop-spacings increase energy cost especially for high target speeds. ► Transport efficiency decreases with shortening stop-spacing for high target speeds. ► Target speed should be dynamically adjusted according to inter-stop distances.

  5. Speed Control Of Induction Motor Using Dspic30f2023

    M. S. Aspalli

    2013-09-01

    Full Text Available AC motor drives are widely used to control the speed of conveyor systems, blower speeds, pump speeds, machine tool speeds and other applications that require variable speed with variable torque. The main aim of the work is to design and develop an electronic system that can be used to control the speed of a three phase induction motor.The speed of the three phase induction motor can be controlled by various methods. The stator frequency control is one of the simplest methods to control the speed of IM and the same method is employed.In the proposed scheme, dsPIC30F2023 controller is used to produce control signals for switches (IGBTs. It is a 44 pin IC. As compared to the PIC controller and DSP, dsPIC is cheaper and most reliable. The dsPIC DSC has the “heart” of a 16-bit MCU with robust peripherals and fast interrupt handling capability and the “brain” of a DSP that manages high computation activities, creating the optimum single chip solution for embedded system designs.

  6. Police enforcement and driving speed.

    2008-01-01

    Speed limits are violated frequently in the Netherlands. As speed is an important factor in road crashes, the surveillance of driving speeds is one of the spearheads in the policy plans of the Dutch police. Different methods of speed enforcement have proved to be effective in reducing speed and cras

  7. Speed Control of Induction Motor using FOC Method

    Hafeezul Haq

    2015-03-01

    Full Text Available An increasing number of applications in high performing electrical drive systems use nowadays, squirrel-cage induction motors. This paper describes a simplified method for the speed control of a three phase AC drive using Proportional-Integral controller. The simulation results show that the step response of the model is very fast, steady and able to work in four quadrants, and robustness and high performance is achieved.

  8. How Fast Wages Adjust to Prices: A Multi Country Analysis

    Mohsen Bahmani-oskooee; Massoumeh Hajilee

    2011-01-01

    The adjustment of nominal wages to inflation has implications on the labor market as well as on other areas in economics. In this paper, we employ the Blanchard and Katz (1997, 1999) model of nominal wage determination and try to estimate the adjustment speed. By using the bounds testing approach for cointegration and error-correction modeling we distinguish the short run from the long run. The model is estimated for 29 countries using annual data over the period 1975-2006. We find that infla...

  9. Variance Adjusted Actor Critic Algorithms

    Tamar, Aviv; Mannor, Shie

    2013-01-01

    We present an actor-critic framework for MDPs where the objective is the variance-adjusted expected return. Our critic uses linear function approximation, and we extend the concept of compatible features to the variance-adjusted setting. We present an episodic actor-critic algorithm and show that it converges almost surely to a locally optimal point of the objective function.

  10. Mood Adjustment via Mass Communication.

    Knobloch, Silvia

    2003-01-01

    Proposes and experimentally tests mood adjustment approach, complementing mood management theory. Discusses how results regarding self-exposure across time show that patterns of popular music listening among a group of undergraduate students differ with initial mood and anticipation, lending support to mood adjustment hypotheses. Describes how…

  11. Effect of wind speed on accuracy of Turc method in a humid climate

    Trajković Slaviša

    2007-01-01

    Full Text Available The Turc method is one of the simplest and most accurate empirical equations used for ETO estimation. The objectives of this study are: first, to investigate the effect of wind speed on accuracy of Turc method; second, to develop the wind speed adjustment factors for the Turc method. The adjusted Turc method provides the quite good agreement with the evapotranspiration obtained by the FAO-56 Penman-Monteith method. It gave reliable estimation at all the locations and it has proven to be the most adjustable to the local climatic conditions. These results recommend the adjusted Turc method for estimating reference evapotranspiration.

  12. Bayes linear covariance matrix adjustment

    Wilkinson, Darren J

    1995-01-01

    In this thesis, a Bayes linear methodology for the adjustment of covariance matrices is presented and discussed. A geometric framework for quantifying uncertainties about covariance matrices is set up, and an inner-product for spaces of random matrices is motivated and constructed. The inner-product on this space captures aspects of our beliefs about the relationship between covariance matrices of interest to us, providing a structure rich enough for us to adjust beliefs about unknown matrices in the light of data such as sample covariance matrices, exploiting second-order exchangeability and related specifications to obtain representations allowing analysis. Adjustment is associated with orthogonal projection, and illustrated with examples of adjustments for some common problems. The problem of adjusting the covariance matrices underlying exchangeable random vectors is tackled and discussed. Learning about the covariance matrices associated with multivariate time series dynamic linear models is shown to be a...

  13. AcEST: DK950895 [AcEST

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

  14. A New Coordinated Voltage Control Scheme for Offshore AC Grid of HVDC Connected Offshore Wind Power Plants

    Sakamuri, Jayachandra N.; Nicolaos Antonio CUTULULIS; Rather, Zakir Hussain; Rimez, Johan

    2015-01-01

    This paper proposes a coordinated voltage control scheme (CVCS) which enhances the voltage ride through (VRT) capability of an offshore AC grid comprised of a cluster of offshore wind power plants (WPP) connected through AC cables to the offshore voltage source converter based high voltage DC (VSC-HVDC) converter station. Due to limited short circuit power contribution from power electronic interfaced variable speed wind generators and with the onshore main grid decoupled by the HVDC link, th...

  15. AcEST: BP914304 [AcEST

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

  16. AcEST: BP911793 [AcEST

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

  17. AcEST: BP921649 [AcEST

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

  18. AcEST: BP919669 [AcEST

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

  19. AcEST: DK957916 [AcEST

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

  20. AcEST: DK956923 [AcEST

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

  1. AcEST: BP921492 [AcEST

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

  2. Fault tolerant wind speed estimator used in wind turbine controllers

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2012-01-01

    Advanced control schemes can be used to optimize energy production and cost of energy in modern wind turbines. These control schemes most often rely on wind speed estimations. These designs of wind speed estimators are, however, not designed to be fault tolerant towards faults in the used sensors...... applying the proposed wind speed estimator to a simulation model of a wind turbine. Notice that since the faults are accommodated in the observer scheme the actual controller do not need to be adjusted or reconfigured to accommodate the sensor faults....

  3. Variable Speed Rotor System Project

    National Aeronautics and Space Administration — Variable speed rotors will give helicopters several advantages: higher top speed, greater fuel efficiency, momentary emergency over-power, resonance detuning...

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

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

    2008-03-01

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

  5. Simultaneous distribution of AC and DC power

    Polese, Luigi Gentile

    2015-09-15

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

  6. Image optimization procedures for the Fuji AC-1

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

    1993-06-01

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

  7. High speed photography

    Slemc, Tadej

    2010-01-01

    The main purpose of photography is to capture a moment in time and transfer the captured information onto the photographic paper. High speed photography is a photography technique in which parts of a very fast phenomenon are being captured. A phenomenon, which usually happens too fast to be captured by the human eye. An example of such is contact of a water drop with another surface. A person is capable to register the contact, but it is only by means of the high speed photography that one is...

  8. Pitch Angle Control for Variable Speed Wind Turbines

    Chen, Zhe; Zhang, Jianzhong; Cheng, M;

    2008-01-01

    Pitch angle control is the most common means for adjusting the aerodynamic torque of the wind turbine when wind speed is above rated speed and various controlling variables may be chosen, such as wind speed, generator speed and generator power. As conventional pitch control usually use PI...... controller, the mathematical model of the system should be known well. A fuzzy logic pitch angle controller is developed in this paper, in which it does not need well known about the system and the mean wind speed is used to compensate the non-linear sensitivity. The fuzzy logic control strategy may have...... the potential when the system contains strong non-linearity, such as wind turbulence is strong, or the control objectives include fatigue loads. The design of the fuzzy logic controller and the comparisons with conversional pitch angle control strategies with various controlling variables are carried out...

  9. Induction generator produces constant-frequency voltage from variable-speed drive

    Riaz, M.

    1970-01-01

    Two-stage polyphase generator is usable as induction motor operable over range of speeds while powered from constant frequency source. It requires neither slip rings nor special adjustable-frequency power supplies or external reactive sources.

  10. The Measurement of the Speed of Light Using a Laser Pointer.

    Mak, Se-yuen; Yip, Din-yan

    2000-01-01

    Presents a method for measuring the speed of light using a laser pointer with adjustable focus as the signal carrier, a signal generator to modulate the light beam, and a student oscilloscope to detect the phase shift. (Author/CCM)

  11. Adjustable Induction-Heating Coil

    Ellis, Rod; Bartolotta, Paul

    1990-01-01

    Improved design for induction-heating work coil facilitates optimization of heating in different metal specimens. Three segments adjusted independently to obtain desired distribution of temperature. Reduces time needed to achieve required temperature profiles.

  12. Adjustment to Spinal Cord Injury

    ... may need to work to help with family finances. All of the changes that they face can ... 2000). Goal instability and adjustment to physical disability. Journal of Counseling Psychology, 47(2). 251-265. This ...

  13. Regulating vacuum pump speed with feedback control

    Considerable energy is wasted by the vacuum pump/motor on dairy farms. The output capacity (m3/min or cfm) of the vacuum pump always exceeds the capacity needed to milk cows and wash pipelines. Vacuum pumps run at full speed and load regardless of actual need for air. Excess air is admitted through a controller. Energy can be saved from electrical demand reduced by regulating vacuum pump speed according to air based on air usage. An adjustable speed drive (ASD) on the motor and controlled based upon air usage, can reduce the energy used by the vacuum pump. However, the ASD unit tested could not maintain vacuum levels within generally accepted guidelines when air usage changed. Adding a high vacuum reserve and a dual vacuum controller between the vacuum pump and the milking pipeline brought vacuum stability within guidelines. The ASD/dual vacuum system can reduce energy consumption and demand by at least 50 percent during milking and provide better vacuum stability than conventional systems. Tests were not run during washing cycles. Using 1990 costs and only the energy saved during milking, the simple payback on investment in new equipment for a 5 hp motor, speed controller and vacuum regulator would be about 5 years

  14. Negative hydrogen ion beam extraction from an AC heated cathode driven Bernas-type ion source

    Okano, Y.; Miyamoto, N.; Kasuya, T.; Wada, M.

    2015-04-01

    A plasma grid structure was installed to a Bernas-type ion source used for ion implantation equipment. A negative hydrogen (H-) ion beam was extracted by an AC driven ion source by adjusting the bias to the plasma grid. The extracted electron current was reduced by positively biasing the plasma grid, while an optimum plasma grid bias voltage for negative ion beam extraction was found to be positive 3 V with respect to the arc chamber. Source operations with AC cathode heating show extraction characteristics almost identical to that with DC cathode heating, except a minute increase in H- current at higher frequency of cathode heating current.

  15. Adjustment techniques for experimental data

    To carry through numerically the different adjustment of experimental data planned by National Institute of Nuclear Research investigators. It is presented the different adjustment techniques of experimental data which are fundamentally for: linear least squares, non linear with restrictions. Methodology: Lineal least squares - Orthogonal decomposition via Householder reflections. No lineal - Method of general lowering and quasi Newton; Levenberg-Marquardt modified - More version. No lineal with restrictions - Quadratic sequential programming method (In process). (Author)

  16. Cloud speed sensor

    V. Fung

    2013-10-01

    Full Text Available Changing cloud cover is a major source of solar radiation variability and poses challenges for the integration of solar energy. A compact and economical system that measures cloud motion vectors to estimate power plant ramp rates and provide short term solar irradiance forecasts is presented. The Cloud Speed Sensor (CSS is constructed using an array of luminance sensors and high-speed data acquisition to resolve the progression of cloud passages across the sensor footprint. An embedded microcontroller acquires the sensor data and uses a cross-correlation algorithm to determine cloud motion vectors. The CSS was validated against an artificial shading test apparatus, an alternative method of cloud motion detection from ground measured irradiance (Linear Cloud Edge, LCE, and a UC San Diego Sky Imager (USI. The CSS detected artificial shadow directions and speeds to within 15 and 6% accuracy, respectively. The CSS detected (real cloud directions and speeds without average bias and with average weighted root mean square difference of 22° and 1.9 m s−1 when compared to USI and 33° and 1.5 m s−1 when compared to LCE results.

  17. Variable speed generators

    Boldea, Ion

    2005-01-01

    With the deregulation of electrical energy production and distribution, says Boldea (Polytechnical Institute, Timisoara, Romania) producers are looking for ways to tailor their electricity for different markets. Variable-speed electric generators are serving that purpose, up to the 400 megavolt ampere unit size, in Japan since 1996 and Germany sinc

  18. High Speed Network Sampling

    2005-01-01

    Abstract Classical Sampling methods play an important role in the current practice of Internet measurement. With today’s high speed networks, routers cannot manage to generate complete Netflow data for every packet. They have to perform restricted sampling. This thesis summarizes some of the most important sampling schemes and their applications before diving into an analysis on the effect of sampling Netflow records.

  19. Speed mathematics simplified

    Stoddard, Edward

    1994-01-01

    Entertaining, easy-to-follow suggestions for developing greater speed and accuracy in doing mathematical calculations. Surefire methods for multiplying without carrying, dividing with half the pencil work of long division, plus advice on how to add and subtract rapidly, master fractions, work quickly with decimals, handle percentages, and much more.

  20. More Than Just Speed

    2008-01-01

    Following more than 10 years of deliberation and planning,construc- tion of the 1,320-km Beijing-Shanghai High-speed Railway began in mid- April.Following the world’s most elevated Qinghai-Tibet Railway,which

  1. Speeding Up Innovation

    Sørensen, Flemming; Mattsson, Jan

    2016-01-01

    Minimisation of time-to-market strategies can provide companies with a competitive advantage in dynamic and competitive environments. Using parallel innovation processes has been emphasised as one strategy to speed up innovation processes and consequently minimise the time-to-market of innovations...

  2. High speed network sampling

    2010-01-01

    Abstract Classical Sampling methods play an important role in the current practice of Internet measurement. With today’s high speed networks, routers cannot manage to generate complete Netflow data for every packet. They have to perform restricted sampling. This thesis summarizes some of the most important sampling schemes and their applications before diving into an analysis on the effect of sampling Netflow records.

  3. AC, DC or EC motor? What type of engine for what purpose?; AC-, DC- oder EC-Motor? Welche Motorausfuehrung fuer welchen Zweck

    Zeiff, Andreas; Homburg, Dietrich

    2009-01-15

    Electronics is the key technology in control engineering, but even the best control system requires reliable modules to transmit signals. Modern electric motors have become indispensable here. There are nearly as many motor types as there are applications. Electromagnetic conversion of electric into mechanical power is directly related to motor design. There are AC and DC motors, one-speed motors and variable-speed motors. Rotary momentum and synchronisation can be optimized by selecting the appropriate motor type, as can dynamics and detent torque. Correct selection of the electric motor therefore is essential for an optimal drive concept. (orig.)

  4. AcEST: DK948526 [AcEST

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

  5. AcEST: DK962916 [AcEST

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

  6. AcEST: DK955705 [AcEST

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

  7. AcEST: DK961330 [AcEST

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

  8. AcEST: BP913772 [AcEST

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

  9. AcEST: DK952954 [AcEST

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

  10. AcEST: BP912540 [AcEST

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

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

    Mabano, Michel

    2016-01-01

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

  12. Skeletal muscle mass adjusted by height correlated better with muscular functions than that adjusted by body weight in defining sarcopenia.

    Han, Der-Sheng; Chang, Ke-Vin; Li, Chia-Ming; Lin, Yu-Hong; Kao, Tung-Wei; Tsai, Keh-Sung; Wang, Tyng-Grey; Yang, Wei-Shiung

    2016-01-01

    Sarcopenia, characterized by low muscle mass and function, results in frailty, comorbidities and mortality. However, its prevalence varies according to the different criteria used in its diagnosis. This cross-sectional study investigated the difference in the number of sarcopenia cases recorded by two different measurement methods of low muscle mass to determine which measurement was better. We recruited 878 (54.2% female) individuals aged over 65 years and obtained their body composition and functional parameters. Low muscle mass was defined as two standard deviations below either the mean height-adjusted (hSMI) or weight-adjusted (wSMI) muscle mass of a young reference group. The prevalence of sarcopenia was 6.7% vs. 0.4% (male/female) by hSMI, and 4.0% vs. 10.7% (male/female) by wSMI. The κ coefficients for these two criteria were 0.39 vs. 0.03 (male/female), and 0.17 in all subjects. Serum myostatin levels correlated positively with gait speed (r = 0.142, p = 0.007) after adjustment for gender. hSMI correlated with grip strength, cardiopulmonary endurance, leg endurance, gait speed, and flexibility. wSMI correlated with grip strength, leg endurance, gait speed, and flexibility. Since hSMI correlated more closely with grip strength and more muscular functions, we recommend hSMI in the diagnosis of low muscle mass. PMID:26785759

  13. Speed-calming measures and their Effect on driving speed

    Agerholm, Niels; Knudsen, Daniel; Variyeswaran, Kajan

    2016-01-01

    Speeding increases the risk and severity of accidents, especially for vulnerable road users. Hence, minimisation of speeding in built-up areas is vital. Some countries widely use speed-calming measures (SCs). Documentation shows that SCs reduce speeding considerably although various types and...... designs of SCs affect this reduction. This paper includes studies of the effects from establishment of sinus speed humps of height 10 cm and length 950 cm and chicanes (with a free carriageway width of 5,30 cm and a length between the 0.5 m wide obstacles of 18 m) as a before/after study where the speed....... Despite the apparent absence of more distant effects of each SC, there is an overall reduced average speed on the full length of a road with SCs. Humps reduce the mean speed comparable to the reduction from chicanes, but the speed variation is less reduced near chicanes, and especially prior to the...

  14. DIAGNOSTIC FEATURES RESEARCH OF AC ELECTRIC POINT MOTORS

    S. YU. Buryak

    2014-05-01

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

  15. 7 CFR 251.7 - Formula adjustments.

    2010-01-01

    ... 7 Agriculture 4 2010-01-01 2010-01-01 false Formula adjustments. 251.7 Section 251.7 Agriculture... GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION THE EMERGENCY FOOD ASSISTANCE PROGRAM § 251.7 Formula adjustments. Formula adjustments. (a) Commodity adjustments. The Department will make annual adjustments...

  16. Improving speed behaviour : the potential of in-car speed assistance and speed limit credibility.

    Nes, C.N. van Houtenbos, M. & Schagen, I.N.L.G. van

    2009-01-01

    Speeding is still a common practice on many roads and it contributes to a significant number of crashes. Two new approaches to solve speeding issues are focused on: intelligent speed assistance systems (ISA) and speed limit credibility. Research has indicated that ISA is promising with respect to im

  17. Constant Speed Ramps

    Perdomo, Oscar M

    2013-01-01

    In this paper we show all possible ramps where an object can move with constant speed under the effect of gravity and friction. The planar ramp are very easy to describe, just rotate a curve with velocity vector (tanh(as),sech(as)). Recall that tanh(as)^2+sech^2(as) = 1. Therefore, the solution of the planar constant speed problem is connected with easy to describe examples of curves with arc-length parameter. For ramps in the space, we show that there are as many ramps as tangent unit vector fields in the south hemisphere. A video explaining these results can be found at http://www.youtube.com/watch?v=iBrvbb0efVk

  18. Stability control for high speed tracked unmanned vehicles

    Pape, Olivier; Morillon, Joel G.; Houbloup, Philippe; Leveque, Stephane; Fialaire, Cecile; Gauthier, Thierry; Ropars, Patrice

    2005-05-01

    The French Military Robotic Study Program (introduced in Aerosense 2003), sponsored by the French Defense Procurement Agency and managed by Thales as the prime contractor, focuses on about 15 robotic themes which can provide an immediate "operational add-on value". The paper details the "automatic speed adjustment" behavior (named SYR4), developed by Giat Industries Company, which main goal is to secure the teleoperated mobility of high speed tracked vehicles on rough grounds; more precisely, the validated low level behavior continuously adjusts the vehicle speed taking into account the teleperator wish AND the maximum speed that the vehicle can manage safely according to the commanded radius of curvature. The algorithm is based on a realistic physical model of the ground-tracks relation, taking into account many vehicle and ground parameters (such as ground adherence and dynamic specificities of tracked vehicles). It also deals with the teleoperator-machine interface, providing a balanced strategy between both extreme behaviors: a) maximum speed reduction before initiating the commanded curve; b) executing the minimum possible radius without decreasing the commanded speed. The paper presents the results got from the military acceptance tests performed on tracked SYRANO vehicle (French Operational Demonstrator).

  19. Universality of ac conduction in disordered solids

    Dyre, Jeppe; Schrøder, Thomas

    2000-01-01

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

  20. High speed door assembly

    Shapiro, C.

    1991-12-31

    This invention is comprised of a high speed door assembly, comprising an actuator cylinder and piston rods, a pressure supply cylinder and fittings, an electrically detonated explosive bolt, a honeycomb structured door, a honeycomb structured decelerator, and a structural steel frame encasing the assembly to close over a 3 foot diameter opening within 50 milliseconds of actuation, to contain hazardous materials and vapors within a test fixture.

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

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

  2. MCCB warm adjustment testing concept

    Erdei, Z.; Horgos, M.; Grib, A.; Preradović, D. M.; Rodic, V.

    2016-08-01

    This paper presents an experimental investigation in to operating of thermal protection device behavior from an MCCB (Molded Case Circuit Breaker). One of the main functions of the circuit breaker is to assure protection for the circuits where mounted in for possible overloads of the circuit. The tripping mechanism for the overload protection is based on a bimetal movement during a specific time frame. This movement needs to be controlled and as a solution to control this movement we choose the warm adjustment concept. This concept is meant to improve process capability control and final output. The warm adjustment device design will create a unique adjustment of the bimetal position for each individual breaker, determined when the testing current will flow thru a phase which needs to trip in a certain amount of time. This time is predetermined due to scientific calculation for all standard types of amperages and complies with the IEC 60497 standard requirements.

  3. Short term dynamic aperture with AC dipoles

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

    2015-01-01

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

  4. Evaluation of adjustment functions in a heuristic algorithm

    At present the techniques of evolution al computation receive an increasing attention in the scientific and technological areas. This situation is due to its enormous potential in the optimization applied to problems of discussed computational complexity. In the nuclear area these techniques are used in diverse problems of combinatory optimization related with designing cores of power reactors. A distinctive characteristic of the evolution al and/or meta-heuristic algorithms is that appeal in each one from their applications to an adjustment function, fitness or of quality. This function allows to discriminate or to evaluate potentials solutions of the problem to solve. The definition of this situation is very important since it allows following the search of the algorithm toward different regions of the search space. In this work the impact that has the election of this function in the quality of the found solution is shown. The optimization technique by ant colonies or Acs (ant colony system) was used applied to the radial design of fuel cells for a boiling water power reactor. The notable results of the Acs allowed to propose the adjustment method of the importance and with this to obtain adjustment functions that guide the search of solutions of collective algorithms efficiently, basic capacity to develop the proposal of emulation of the natural selection and to investigate the possibility that on order of specify goals, to obtain the corresponding decision variables. A variety of re tro-exit (re tro-out) complementary process of feedback (re tro-in) that opens extended application perspectives of be feasible. (Author)

  5. ac electroosmosis in rectangular microchannels.

    Campisi, Michele; Accoto, Dino; Dario, Paolo

    2005-11-22

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

  6. DESARROLLO RURAL A.C.

    Alfredo Aguilar Valdés

    2015-01-01

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

  7. Enhancement of quantum speed limit time due to cooperative effects in multilevel systems

    Deriving minimum evolution times is of paramount importance in quantum mechanics. Bounds on the speed of evolution are given by the so called quantum speed limit (QSL). In this work we use quantum optimal control methods to study the QSL for driven many level systems which exhibit local two-level interactions in the form of avoided crossings (ACs). Remarkably, we find that optimal evolution times are proportionally smaller than those predicted by the well-known two-level case, even when the ACs are isolated. We show that the physical mechanism for such enhancement is due to non-trivial cooperative effects between the AC and other levels, which are dynamically induced by the shape of the optimized control field. (fast track communication)

  8. Tax Adjusted for Imported Equipment

    2010-01-01

    @@ Ministry of Finance, Central Administration of Customs, and State Administration of Taxation of P.R. of China jointly issued a "Notice on the Lists Related to the Interim Provisions on the Adjustment of Import Tax Policy on Major Technical Equipment" (the Notice) on April 13rd to adjust the list of equipment catalog and merchandise attached to the "Interim Provisions on the Import Tax Policy on Major Technical Equipment", as well as the preferential scope and extent of the import tax on a number of major technical equipment.

  9. 75 FR 33379 - Railroad Cost Recovery Procedures-Productivity Adjustment; Quarterly Rail Cost Adjustment Factor

    2010-06-11

    ... Surface Transportation Board Railroad Cost Recovery Procedures--Productivity Adjustment; Quarterly Rail... Railroads that the Board restate the previously published productivity adjustment for the 2003-2007 averaging period (2007 productivity adjustment) so that it tracks the 2007 productivity adjustment...

  10. Microcontroller based PWM Inverter for Speed Control of a Three Phase Induction Motor

    M. A. Latif

    2013-04-01

    Full Text Available Three phase induction motor has proven to be an extremely reliable electromechanical energy conversion device for over 100 years. The speed control of induction motor is a crying need for the real world industrial applications. However, there are so many options available for the precise speed control of induction motor except by changingthe frequency. Therefore to achieve the goal of speed control of induction motor, there is no alternative of inverters. With the availability of high speed power semiconductor devices, the three phase inverters play the key role for variable speed ac motor drives. In addition to the speed control, the inverter can also provide some unique features, like voltage control, torque control, power factor correction, auto breaking, built in protection system and so forth.In this paper, a three phases PWM inverter using MC3PHAC microcontroller with computer interface is proposed to run a squirrel case induction motor. Some results of the proposed inverter are presented.

  11. On the speed of fast and slow rupture fronts along frictional interfaces

    Trømborg, Jørgen Kjoshagen; Thøgersen, Kjetil; Scheibert, Julien; Malthe-Sørenssen, Anders

    2015-01-01

    The transition from stick to slip at a dry frictional interface occurs through the breaking of the junctions between the two contacting surfaces. Typically, interactions between the junctions through the bulk lead to rupture fronts propagating from weak and/or highly stressed regions, whose junctions break first. Experiments find rupture fronts ranging from quasi-static fronts with speeds proportional to external loading rates, via fronts much slower than the Rayleigh wave speed, and fronts that propagate near the Rayleigh wave speed, to fronts that travel faster than the shear wave speed. The mechanisms behind and selection between these fronts are still imperfectly understood. Here we perform simulations in an elastic 2D spring--block model where the frictional interaction between each interfacial block and the substrate arises from a set of junctions modeled explicitly. We find that a proportionality between material slip speed and rupture front speed, previously reported for slow fronts, actually holds ac...

  12. A Chiller Control Algorithm for Multiple Variable-speed Centrifugal Compressors

    Caballero, Piero; Shih, Chiang; Thornton, W. Turner; Brasz, Joost J.

    2014-01-01

    Capacity control of a chiller with multiple variable-speed centrifugal compressors running in parallel between a common evaporator and condenser under reduced load conditions can be achieved by speed variation and/or adjusting the number of compressors in operation. These different capacity control schemes result in modifications of chiller efficiency under part-load conditions. The decision in selecting the number of operational compressors matching the compressor rotational speed to reach a...

  13. Rotor speed estimation for indirect stator flux oriented induction motor drive based on MRAS scheme

    Youssef Agrebi; Moncef Triki; Yassine Koubaa; Mohamed Boussak

    2007-01-01

    In this paper, a conventional indirect stator flux oriented controlled (ISFOC) induction motor drive is presented. In order to eliminate the speed sensor, an adaptation algorithm for tuning the rotor speed is proposed. Based on the model reference adaptive system (MRAS) scheme, the rotor speed is tuned to obtain an exact ISFOC induction motor drive. The reference and adjustable models, developed in stationary stator reference frame, are used in the MRAS scheme to estimate induction rotor peed...

  14. The Relation of Speeded and Unspeeded Reasoning with Mental Speed.

    Wilhelm, Oliver; Schulze, Ralf

    2002-01-01

    Studied the contribution of mental speed to task performance on reasoning tasks under timed and untimed conditions for 227 participants and for 90 participants working under time conditions. Results suggest that the use of speeded reasoning tests is likely to lead to overestimates of the relation between mental speed and reasoning ability. (SLD)

  15. INSTRUMENTATION AND TECHNIQUES. A SELF-CONTAINED, REGULATED, BURST-FIRING CONSTANT-CURRENT AC SHOCK GENERATOR

    A line- and load-regulated constant-current ac shock generator has been designed for animal behavior experiments. The self-contained unit has four operating modes, amplitude adjustment, and a leakage current detection circuit. A unique feature of this generator is that the good l...

  16. AcEST: BP920845 [AcEST

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

  17. AcEST: DK960083 [AcEST

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

  18. AcEST: DK955376 [AcEST

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

  19. AcEST: BP913416 [AcEST

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

  20. AcEST: DK947388 [AcEST

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

  1. AcEST: BP916217 [AcEST

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

  2. AcEST: DK953324 [AcEST

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

  3. AcEST: DK945049 [AcEST

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

  4. An adjustable contracted CI method

    王育彬; 甘正汀; 苏克和; 文振翼

    1999-01-01

    A new contracted CI scheme——adjustable contracted CI scheme——is presented and programed. The efficiency of this scheme is tested by some example calculations. The result shows that the application of the new scheme is flexible and the correlation energy loss is lower than that of the original externally contracted CI method.

  5. Self-Adjusting Stack Machines

    Hammer, Matthew A; Chen, Yan; Acar, Umut A

    2011-01-01

    Self-adjusting computation offers a language-based approach to writing programs that automatically respond to dynamically changing data. Recent work made significant progress in developing sound semantics and associated implementations of self-adjusting computation for high-level, functional languages. These techniques, however, do not address issues that arise for low-level languages, i.e., stack-based imperative languages that lack strong type systems and automatic memory management. In this paper, we describe techniques for self-adjusting computation which are suitable for low-level languages. Necessarily, we take a different approach than previous work: instead of starting with a high-level language with additional primitives to support self-adjusting computation, we start with a low-level intermediate language, whose semantics is given by a stack-based abstract machine. We prove that this semantics is sound: it always updates computations in a way that is consistent with full reevaluation. We give a comp...

  6. Adjustable Optical-Fiber Attenuator

    Buzzetti, Mike F.

    1994-01-01

    Adjustable fiber-optic attenuator utilizes bending loss to reduce strength of light transmitted along it. Attenuator functions without introducing measurable back-reflection or insertion loss. Relatively insensitive to vibration and changes in temperature. Potential applications include cable television, telephone networks, other signal-distribution networks, and laboratory instrumentation.

  7. Adjustment or updating of models

    D J Ewins

    2000-06-01

    In this paper, first a review of the terminology used in the model adjustment or updating is presented. This is followed by an outline of the major updating algorithms cuurently available, together with a discussion of the advantages and disadvantages of each, and the current state-of-the-art of this important application and part of optimum design technology.

  8. DAC for High Speed and Low Power Applications Using Abacus

    Shankarayya G. Kambalimath

    2014-02-01

    Full Text Available This paper proposes a Chinese Abacus Digital-to-Ana log Converter (DAC for high speed and low power applications like audio and video applica tions. This circuit of DAC uses resister strings to get a good analog output. The designed D AC uses the algorithm of abacus. Instead of using binary code, here we use abacus code to contr ol the switches. So the complexity and the area will be reduced automatically. The 8-bit D AC is comprised of 12 resistors and 24 NMOS switches. The 8-bit Abacus resistor DAC requires 12 resistors and 24 switches. The 8-bit resistor-string DAC requires 255 resistors and 256 switches. The most important advantages are that the numbers of both resistors and switches are all reduced effectively. The simulation environment uses 1 μ m process technology

  9. Sensorless Vector Control of AC Induction Motor Using Sliding-Mode Observer

    Phuc Thinh Doan

    2013-06-01

    Full Text Available This paper develops a sensorless vector controlled method for AC induction motor using sliding-mode observer. For developing the control algorithm, modeling of AC induction motor is presented. After that, a sliding mode observer is proposed to estimate the motor speed, the rotor flux, the angular position of the rotor flux and the motor torque from monitored stator voltages and currents. The use of the nonlinear sliding mode observer provides very good performance for both low and high speed motor operation. Furthermore, the proposed system is robust in motor losses and load variations. The convergence of the proposed observer is obtained using the Lyapunov theory. Hardware and software for simulation and experiment of the AC induction motor drive are introduced. The hardware consists of a 1.5kw AC induction motor connected in series with a torque sensor and a powder brake. A controller is developed based on DSP TMS320F28355. The simulation and experimental results illustrate that fast torque and speed response with small torque ripples can be achieved. The proposed control scheme is suitable to the application fields that require high performance of torque response such as electric vehicles. doi:http://dx.doi.org/10.12777/ijse.4.2.2013.39-43 [How to cite this article: Doan, P. T., Nguyen, T. T., Jeong, S. K., Oh, S. J., & Kim, S. B. (2013. Sensorless Vector Control of AC Induction Motor Using Sliding-Mode Observer. INTERNATIONAL JOURNAL OF SCIENCE AND ENGINEERING, 4(2, 39-43; doi: http://dx.doi.org/10.12777/ijse.4.2.2013.39-43

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

    Domanskyi, I. V.

    2015-01-01

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

  11. Safe Speeds and Credible Speed Limits (SaCredSpeed): New Vision for Decision Making on Speed Management.

    Aarts, L. Nes, N. van Wegman, F.C.M. Schagen, I.N.L.G. van & Louwerse, R.

    2009-01-01

    Speed is an inherent characteristic of mobility and a hazard to safety. Several approaches exist of how to manage speed. In the Netherlands, the emphasis has mainly been on harm minimisation during the last decades, due to the implementation of the Sustainable Safety vision. Speed management remains

  12. Pay as You Speed, ISA with incentive for not speeding

    Lahrmann, Harry; Agerholm, Niels; Tradisauskas, Nerius;

    2012-01-01

    To simulate a market introduction of Intelligent Speed Adaptation (ISA) and to study the effect of a Pay as You Speed (PAYS) concept, a field trial with 153 drivers was conducted during 2007–2009. The participants drove under PAYS conditions for a shorter or a longer period. The PAYS concept...... consisted of informative ISA linked with economic incentive for not speeding, measured through automatic count of penalty points whenever the speed limit was exceeded. The full incentive was set to 30% of a participant's insurance premium. The participants were exposed to different treatments, with and...... without incentive crossed with informative ISA present or absent. The results showed that ISA is an efficient tool for reducing speeding particularly on rural roads. The analysis of speed data demonstrated that the proportion of distance driven above the speed where the ISA equipment responded (PDA) was a...

  13. Proactive adjustments of response strategies in the stop-signal paradigm

    Verbruggen, Frederick; Logan, Gordon D.

    2009-01-01

    In the stop-signal paradigm, fast responses are harder to inhibit than slow responses, so subjects must balance speed on the go task with successful stopping in the stop task. In theory, subjects achieve this balance by adjusting response thresholds for the go task, making proactive adjustments in response to instructions that indicate that relevant stop signals are likely to occur. We report five experiments that tested this theoretical claim, presenting cues that indicated whether or not st...

  14. 12 CFR 19.240 - Inflation adjustments.

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Inflation adjustments. 19.240 Section 19.240... PROCEDURE Civil Money Penalty Inflation Adjustments § 19.240 Inflation adjustments. (a) The maximum amount... Civil Penalties Inflation Adjustment Act of 1990 (28 U.S.C. 2461 note) as follows: ER10NO08.001 (b)...

  15. High Speed Flexible Optical Disk with Cylindrically Concaved Stabilizer

    Aman, Yasutomo; Onagi, Nobuaki; Murata, Shozo; Sugimoto, Yasunori; Koide, Daiichi; Tokumaru, Haruki

    2007-06-01

    We developed a brand-new stabilizer with a cylindrically concaved active surface for a flexible optical disk system. The unique design enabled extremely stable driving of the flexible disk at rotational speeds over 10,000 rpm. We actually demonstrated the driving at rotational speeds of up to 15,000 rpm, the spindle motor limit of our optical disk tester. This highest rotational speed promises a maximum data transfer rate of more than 600 Mbps for the recording density of a Blu-ray Disc. This stable state was achieved using a simple control that just adjusts the relative axial position of the stabilizer against the flexible disk. Once the adjustment was made, high stability was maintained over a wide rotational speed, ranging from 4,000 to 15,000 rpm. In this stable state, the axial runout on the pickup scanning line was suppressed to less than 10 μm at all rotational speeds. By achieving this high performance with simplified stabilizer control, we have come close to putting our system into practical use.

  16. A new working principle for ac electro-hydrodynamic on-chip micro-pumps

    Our new type of on-chip micro-pump exploits the ac electro-kinetic forces acting in the volume of a fluid in the presence of a temperature gradient. No mechanically movable parts are used. The velocity of the pump flow observed depends on the frequency and strength of the driving ac field and on the temperature gradient across the pump channel. An integrated heating element allows the temperature gradient to be adjusted. Both ac field electrodes and heating element are platinum structures processed on a glass chip. The pump-channel walls and cover are made from polymer and thin-glass, respectively. In this paper, we present measurements of the fluid velocity as functions of the medium conductivity (0.1-1.3 S m-1) and field frequency (300 kHz-52 MHz), voltage across the field-electrode voltage (0-35 Vrms) and the heating element (1.1-3.6 V). Velocities of up to 120 μm s-1 were observed in the pump channel. The advantage of our new design is an evenly shaped cross-section of the pump channel, which reduces the risk of the channel becoming clogged by debris. Ac-electro-osmosis is not a predominant effect in our structures. Pumping could only be observed when the heating current and ac-pump field were applied simultaneously. The effects observed were simulated with the COMSOL Multiphysics program

  17. Application of variable speed operation on Francis Turbines

    G. P. Heckelsmueller

    2015-04-01

    Full Text Available Francis turbines that are directly coupled to a synchronous generator operate at constant rotational speed around a design point characterized by a given water head, flow and guide vane aperture. When important changes occur in headwater level in power stations with large reservoirs, the turbines suffer a significant loss of efficiency. By applying variable speed technology it may be possible to adapt the runner speed and to operate with a higher efficiency over a wide range of water heads. This investigation is intended to reveal the possible benefits of using variable speed operation in regard to gains in efficiency and power output. Based on model test data it is possible to determine the characteristic curves of unitary speed and unitary flow of the respective prototype turbine for varying guide vane apertures. By varying rotor speed it is possible to maintain values that correspond to maximum efficiency. An analysis is made keeping guide vane aperture constant and introducing a proportionality factor of water flow to corresponding power output. The results show that for guide vane apertures and heads different from the design point, best efficiencies can be kept by adjusting rotor speed. At heads lower than the design head, significant efficiency gains can be achieved. Consequently, a significant proportion of the flow can be saved while generating the same amount of power.

  18. Team-oriented Adaptive Droop Control for Autonomous AC Microgrids

    Shafiee, Qobad; Nasirian, Vahidreza; Guerrero, Josep M.; L. Lewis, Frank; Davoudi, Ali

    2014-01-01

    This paper proposes a distributed control strategy for voltage and reactive power regulation in ac Microgrids. First, the control module introduces a voltage regulator that maintains the average voltage of the system on the rated value, keeping all bus voltages within an acceptable range. Dynamic...... regulator, dynamically fine-tunes the Q-E coefficients to handle the proportional reactive power sharing. Accordingly, locally supplied reactive power of any source is compared with neighbor sources and the local droop coefficient is adjusted to mitigate and, ultimately, eliminate the load mismatch. The...... proposed controllers are fully distributed; i.e., each source requires information exchange with only a few other sources, those in direct contact through the communication infrastructure. A Microgrid test bench is used to verify the proposed controlmethodology, where different test scenarios such as load...

  19. The AC magnetic susceptibility of high temperature superconductors

    Salim, M

    2001-01-01

    This research concerns the development of AC magnetic susceptometers and use of susceptometers in analysing high temperature superconductors. Two of the designs were a differential magnetic susceptometer (DMS) and a double coil screening susceptometer (DCSS) whose descriptions are given in detail including coil design, field measurements, susceptometer operation, experimental instrumentation, phase adjustment, susceptometer calibration and sensitivity for each design. Theoretical details are given regarding each design in order to calculate the complex external and internal susceptibility. Investigation concerning the demagnetisation factor of different geometries, and the significant features and limitation for each design are also provided. The susceptometers were applied to a wide range of YBCO samples, which includes bulk samples with different geometry (i.e. Slabs, disk, powder and thick film) and thin films with different oxygen contents. Several silver sheathed Bi-2223 tapes were also involved. This al...

  20. FLUXCAP: A flux-coupled ac/dc magnetizing device

    Gopman, Daniel B; Kent, Andrew D

    2012-01-01

    We report on an instrument for applying ac and dc magnetic fields by capturing the flux from a rotating permanent magnet and projecting it between two adjustable pole pieces. This can be an alternative to standard electromagnets for experiments with small samples or in probe stations in which an applied magnetic field is needed locally, with advantages that include a compact form-factor, very low power requirements and dissipation as well as fast field sweep rates. This flux capture instrument (FLUXCAP) can produce fields from -400 to +400 mT, with field resolution less than 1 mT. It generates static magnetic fields as well as ramped fields, with ramping rates as high as 10 T/s. We demonstrate the use of this apparatus for studying the magnetotransport properties of spin-valve nanopillars, a nanoscale device that exhibits giant magnetoresistance.

  1. Multi-toning Image Adjustment

    LIU Shi-guang; WANG Xiao-juan; PENG Qun-sheng

    2011-01-01

    Due to the different lighting environments or other reasons, the pixel colors may be quite different in one image which causes distinct visual discontinuities. It makes the analysis and processing of such an image more difficult and sometime impossible. In this paper, a unified multi-toning image adjustment method is proposed to solve this problem. First, a novel unsupervised clustering method was proposed to partition the source and the target image into a certain number of subsets with similar color statistics. By matching the texture characteristics and luminance distribution between the blocks, it can create optimized correspondence. Then, the color information was transferred from the matched pixels in the source blocks to the target ones. Graph cut method was used to optimize the seams between different subsets in the final step. This method can automatically perform color adjustment of a multi-toning image. It is simple and efficient. Various results show the validity of this method.

  2. Control of Adjustable Compliant Actuators

    Berno J.E. Misgeld; Kurt Gerlach-Hahn; Daniel Rüschen; Anake Pomprapa; Steffen Leonhardt

    2014-01-01

    Adjustable compliance or variable stiffness actuators comprise an additional element to elastically decouple the actuator from the load and are increasingly applied to human-centered robotic systems. The advantages of such actuators are of paramount importance in rehabilitation robotics, where requirements demand safe interaction between the therapy system and the patient. Compliant actuator systems enable the minimization of large contact forces arising, for example, from muscular spasticity...

  3. Parenting Perfectionism and Parental Adjustment

    Lee, Meghan A.; Schoppe-Sullivan, Sarah J.; Kamp Dush, Claire M.

    2012-01-01

    The parental role is expected to be one of the most gratifying and rewarding roles in life. As expectations of parenting become ever higher, the implications of parenting perfectionism for parental adjustment warrant investigation. Using longitudinal data from 182 couples, this study examined the associations between societal- and self-oriented parenting perfectionism and new mothers’ and fathers’ parenting self-efficacy, stress, and satisfaction. For mothers, societal-oriented parenting perf...

  4. Focal Adjustment for Star Tracker

    Liu Hai-bo; Jian-kun Yang; Ji-chun Tan; De-zhi Su; Wen-liang Wang; Xiu-jian Li; Hui Jia

    2010-01-01

    Technique of measuring intensity distribution and size of spot image developed has been discussed, which is especially suitable for defocus adjustment in ground test of star tracker. A novel approach for choosing a proper defocusing position has been proposed based on collimator, Gaussian surface fitting method, and other ordinary instruments. It proves to be practical and adequate in the development of distant object tracking such as star tracker.Defence Science Journal, 2010, 60(6), pp.678-...

  5. Speed Limits for Entanglement

    Hartman, Thomas

    2015-01-01

    We show that in any relativistic system, entanglement entropy obeys a speed limit set by the entanglement in thermal equilibrium. The bound is derived from inequalities on relative entropy with respect to a thermal reference state. Thus the thermal state constrains far-from-equilibrium entanglement dynamics whether or not the system actually equilibrates, in a manner reminiscent of fluctuation theorems in classical statistical mechanics. A similar shape-dependent bound constrains the full nonlinear time evolution, supporting a simple physical picture for entanglement propagation that has previously been motivated by holographic calculations in conformal field theory. We discuss general quantum field theories in any spacetime dimension, but also derive some results of independent interest for thermal relative entropy in 1+1d CFT.

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

    M.A INAYATHULLAAH,; Dr. R. Anita

    2010-01-01

    The proposed topology reduces the total harmonic distortion (THD) of a high frequency AC/AC Converter well below the acceptable limit. This paper deals with a novel single phase AC/DC/AC soft switching utility frequency AC to high frequency AC converter. In this paper a single phase full bridge inverter with Vienna rectifier as front end is used instead of conventional diode bridge rectifier to provide continuous sinusoidal input current with nearly unity power factor at the source side with ...

  7. Perfecting the Photometric Calibration of the ACS CCD Cameras

    Bohlin, Ralph C

    2016-01-01

    Newly acquired data and improved data reduction algorithms mandate a fresh look at the absolute flux calibration of the CCD cameras on the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The goals are to achieve a 1\\% accuracy and to make this calibration more accessible to the HST guest investigator. Absolute fluxes from the CALSPEC\\footnote{http://www.stsci.edu/hst/observatory/crds/calspec.html} database for three primary hot 30,000--60,000K WDs define the sensitivity calibrations for the WFC and HRC filters. The external uncertainty for the absolute flux is $\\sim$1\\%, while the internal consistency of the sensitivities in the broadband ACS filters is $\\sim$0.3\\% among the three primary WD flux standards. For stars as cool as K type, the agreement with the CALSPEC standards is within 1\\% at the WFC1-1K subarray position, which achieves the 1\\% precision goal for the first time. After making a small adjustment to the filter bandpass for F814W, the 1\\% precision goal is achieved over the full ...

  8. Perfecting the Photometric Calibration of the ACS CCD Cameras

    Bohlin, Ralph C.

    2016-09-01

    Newly acquired data and improved data reduction algorithms mandate a fresh look at the absolute flux calibration of the charge-coupled device cameras on the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The goals are to achieve a 1% accuracy and to make this calibration more accessible to the HST guest investigator. Absolute fluxes from the CALSPEC1 database for three primary hot 30,000–60,000K WDs define the sensitivity calibrations for the Wide Field Channel (WFC) and High Resolution Channel (HRC) filters. The external uncertainty for the absolute flux is ˜1%, while the internal consistency of the sensitivities in the broadband ACS filters is ˜0.3% among the three primary WD flux standards. For stars as cool as K type, the agreement with the CALSPEC standards is within 1% at the WFC1-1K subarray position, which achieves the 1% precision goal for the first time. After making a small adjustment to the filter bandpass for F814W, the 1% precision goal is achieved over the full F814W WFC field of view for stars of K type and hotter. New encircled energies and absolute sensitivities replace the seminal results of Sirianni et al. that were published in 2005. After implementing the throughput updates, synthetic predictions of the WFC and HRC count rates for the average of the three primary WD standard stars agree with the observations to 0.1%.

  9. Photonic Technologies for Ultra-High-Speed Information Highways

    Bouchoule, S; Lèfevre, R.; Legros, E.;

    1999-01-01

    The ACTS project HIGHWAY (AC067) addresses promising ultra-high speed optoelectronic components and system technologies for 40 Gbit/s time-division-multiplexed (TDM) transport systems. Advanced 40 Gbit/s TDM system lab demonstrators are to be realized and tested over installed field fiber testbeds....... This paper reviews the current status of 40 Gbit/s TDM components and subsystem technologies achieved in HIGHWAY. The results of HIGHWAY 40 Gbit/s TDM systems and field tests will be reported in a subsequent paper. (C) 1999 Academic Press....

  10. In situ local shock speed and transit shock speed

    S. Watari

    Full Text Available A useful index for estimating the transit speeds was derived by analyzing interplanetary shock observations. This index is the ratio of the in situ local shock speed and the transit speed; it is 0.6–0.9 for most observed shocks. The local shock speed and the transit speed calculated for the results of the magnetohydrodynamic simulation show good agreement with the observations. The relation expressed by the index is well explained by a simplified propagation model assuming a blast wave. For several shocks the ratio is approximately 1.2, implying that these shocks accelerated during propagation in slow-speed solar wind. This ratio is similar to that for the background solar wind acceleration.

    Keywords. Interplanetary physics (Flare and stream dynamics; Interplanetary shocks; Solar wind plasma

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

    MEHMET AKBABA

    2012-02-01

    Full Text Available Photovoltaic generators (PVG are increasingly used to provide electricity in remote areas. However, in many applications the DC generated electricity by a PVG need to be converted to AC. Traditionally DC to AC inverters have been widely used for this purpose. In this paper, a different system is proposed in which a self excited induction generator (SEIG driven by a permanent magnet DC motor (DCM and powered from a PVG through a maximum power point tracker (MPPT are used. A step-up chopper is utilized as an MPPT unit. The proposed system is modelled in time domain, and a detailed transient and steady-state analysis are presented. The main reason behind analyzing the system in the time domain is because of the fact that for unknown speeds, the methods developed for steady-state analysis of SEIGs can not be applied. The presented work shows that the full available power of the PVG can be harnessed by selecting suitable values for the duty cycle and the frequency of the step up chopper and the excitation capacitor of the SEIG. It is also shown that with such a combination power utilization efficiency of more than 83% can be achieved.

  12. Non-intrusive speed sensor

    Wyett, L.

    1986-01-01

    In Phase I of the Non-Intrusive Speed Sensor program, a computerized literature search was performed to identify candidate technologies for remote, non-intrusive speed sensing applications in Space Shuttle Main Engine (SSME) turbopumps. The three most promising technologies were subjected to experimental evaluation to quantify their performance characteristics under the harsh environmental requirements within the turbopumps. Although the infrared and microwave approaches demonstrated excellent cavitation immunity in laboratory tests, the variable-source magnetic speed sensor emerged as the most viable approach. Preliminary design of this speed sensor encountered no technical obstacles and resulted in viable and feasible speed nut, sensor housing, and sensor coil designs. Phase II of this program developed the variable-source magnetic speed sensor through the detailed design task and guided the design into breadboard fabrication. The speed sensor and its integral speed nut were evaluated at both unit and system level testing. The final room-temperature and cryogenic spin testing of the hardware demonstrated that the sensor was capable of generating sufficient output signal to enable remote speed sensing from 1500 to 40000 rpm over a speed nut/sensor separation of 3.5 inches.

  13. Characterization of AcMNPV with a deletion of ac69 gene

    Jianhao Ke

    2011-07-01

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

  14. Mixing Board Versus Mouse Interaction In Value Adjustment Tasks

    Bergner, Steven; Kirkpatrick, Arthur E; Möller, Torsten

    2011-01-01

    We present a controlled, quantitative study with 12 participants comparing interaction with a haptically enhanced mixing board against interaction with a mouse in an abstract task that is motivated by several practical parameter space exploration settings. The study participants received 24 sets of one to eight integer values between 0 and 127, which they had to match by making adjustments with physical or graphical sliders. Based on recorded slider motion path data, we developed an analysis algorithm that identifies and measures different types of activity intervals, including error time moving irrelevant sliders and end time in breaks after completing each trial item. Our results showed a significant increase in speed of the mixing board interaction accompanied by reduced perceived cognitive load when compared with the traditional mouse-based GUI interaction. The gains in speed are largely due to the improved times required for the hand to reach for the first slider (acquisition time) and also when moving b...

  15. Noise reduction in AC-coupled amplifiers

    Serrano Finetti, Roberto Ernesto; Pallàs Areny, Ramon

    2014-01-01

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

  16. A Stimulated Raman Scattering CMOS Pixel Using a High-Speed Charge Modulator and Lock-in Amplifier

    Lioe, De Xing; Mars, Kamel; Kawahito, Shoji; Yasutomi, Keita; Kagawa, Keiichiro; Yamada, Takahiro; Hashimoto, Mamoru

    2016-01-01

    A complementary metal-oxide semiconductor (CMOS) lock-in pixel to observe stimulated Raman scattering (SRS) using a high speed lateral electric field modulator (LEFM) for photo-generated charges and in-pixel readout circuits is presented. An effective SRS signal generated after the SRS process is very small and needs to be extracted from an extremely large offset due to a probing laser signal. In order to suppress the offset components while amplifying high-frequency modulated small SRS signal components, the lock-in pixel uses a high-speed LEFM for demodulating the SRS signal, resistor-capacitor low-pass filter (RC-LPF) and switched-capacitor (SC) integrator with a fully CMOS differential amplifier. AC (modulated) components remained in the RC-LPF outputs are eliminated by the phase-adjusted sampling with the SC integrator and the demodulated DC (unmodulated) components due to the SRS signal are integrated over many samples in the SC integrator. In order to suppress further the residual offset and the low frequency noise (1/f noise) components, a double modulation technique is introduced in the SRS signal measurements, where the phase of high-frequency modulated laser beam before irradiation of a specimen is modulated at an intermediate frequency and the demodulation is done at the lock-in pixel output. A prototype chip for characterizing the SRS lock-in pixel is implemented and a successful operation is demonstrated. The reduction effects of residual offset and 1/f noise components are confirmed by the measurements. A ratio of the detected small SRS to offset a signal of less than 10−5 is experimentally demonstrated, and the SRS spectrum of a Benzonitrile sample is successfully observed. PMID:27089339

  17. A Stimulated Raman Scattering CMOS Pixel Using a High-Speed Charge Modulator and Lock-in Amplifier.

    Lioe, De Xing; Mars, Kamel; Kawahito, Shoji; Yasutomi, Keita; Kagawa, Keiichiro; Yamada, Takahiro; Hashimoto, Mamoru

    2016-01-01

    A complementary metal-oxide semiconductor (CMOS) lock-in pixel to observe stimulated Raman scattering (SRS) using a high speed lateral electric field modulator (LEFM) for photo-generated charges and in-pixel readout circuits is presented. An effective SRS signal generated after the SRS process is very small and needs to be extracted from an extremely large offset due to a probing laser signal. In order to suppress the offset components while amplifying high-frequency modulated small SRS signal components, the lock-in pixel uses a high-speed LEFM for demodulating the SRS signal, resistor-capacitor low-pass filter (RC-LPF) and switched-capacitor (SC) integrator with a fully CMOS differential amplifier. AC (modulated) components remained in the RC-LPF outputs are eliminated by the phase-adjusted sampling with the SC integrator and the demodulated DC (unmodulated) components due to the SRS signal are integrated over many samples in the SC integrator. In order to suppress further the residual offset and the low frequency noise (1/f noise) components, a double modulation technique is introduced in the SRS signal measurements, where the phase of high-frequency modulated laser beam before irradiation of a specimen is modulated at an intermediate frequency and the demodulation is done at the lock-in pixel output. A prototype chip for characterizing the SRS lock-in pixel is implemented and a successful operation is demonstrated. The reduction effects of residual offset and 1/f noise components are confirmed by the measurements. A ratio of the detected small SRS to offset a signal of less than 10(-)⁵ is experimentally demonstrated, and the SRS spectrum of a Benzonitrile sample is successfully observed. PMID:27089339

  18. A Stimulated Raman Scattering CMOS Pixel Using a High-Speed Charge Modulator and Lock-in Amplifier

    De Xing Lioe

    2016-04-01

    Full Text Available A complementary metal-oxide semiconductor (CMOS lock-in pixel to observe stimulated Raman scattering (SRS using a high speed lateral electric field modulator (LEFM for photo-generated charges and in-pixel readout circuits is presented. An effective SRS signal generated after the SRS process is very small and needs to be extracted from an extremely large offset due to a probing laser signal. In order to suppress the offset components while amplifying high-frequency modulated small SRS signal components, the lock-in pixel uses a high-speed LEFM for demodulating the SRS signal, resistor-capacitor low-pass filter (RC-LPF and switched-capacitor (SC integrator with a fully CMOS differential amplifier. AC (modulated components remained in the RC-LPF outputs are eliminated by the phase-adjusted sampling with the SC integrator and the demodulated DC (unmodulated components due to the SRS signal are integrated over many samples in the SC integrator. In order to suppress further the residual offset and the low frequency noise (1/f noise components, a double modulation technique is introduced in the SRS signal measurements, where the phase of high-frequency modulated laser beam before irradiation of a specimen is modulated at an intermediate frequency and the demodulation is done at the lock-in pixel output. A prototype chip for characterizing the SRS lock-in pixel is implemented and a successful operation is demonstrated. The reduction effects of residual offset and 1/f noise components are confirmed by the measurements. A ratio of the detected small SRS to offset a signal of less than 10−5 is experimentally demonstrated, and the SRS spectrum of a Benzonitrile sample is successfully observed.

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

    Xiong, Yuan

    2015-04-01

    baseline case, leading to the formation of toroidal vortices. Increased residence time and heat recirculation inside the vortex resulted in appreciable formation of PAHs and soot near the nozzle exit. Decreased residence time along the jet axis through flow acceleration by the vortex led to a reduction in the soot volume fraction in the downstream sooting zone. Electromagnetic force generated by AC was proposed as a viable mechanism for the formation of the toroidal vortex. By varying applied AC in a wide range of frequency and voltage, several insta- bility modes were observed, including flicking flames, partial pinch-off of flames, and spinning flames. High speed imaging together with Mie scattering techniques were combined to reveal the flame dynamics as well as the flow structure inside the flames. Original steady toroidal vortices triggered by AC were noted to exhibit axisymmetric axial instability in the flicking and partial pinch-off modes and non-axisymmetric azimuthal instability in the spinning mode. Electrical measurements were also conducted simultaneously to identify the voltage, current, and electrical power responses. Integrated power was noted to be sensitive to indicate subtle variation of flames properties and to the occurrence of axial instability. Under low frequency AC forcing with electrical conditions not generating toroidal vortices, responses of flames were further investigated. Several nonlinear flame responses, including frequency doubling and tripling phenomena, were identified. Spectral analysis revealed that such nonlinear responses were attributed to the combined effects of triggering buoyancy-induced oscillation of the flame as well as the Lorenz force generated by applying AC. Phase delay behaviors between the applied voltage and the heat release rate (or flame size) were also studied to explore the potential of applying AC in controlling flame instability. It was found that the phase delay had large variations for AC frequency smaller than

  20. High speed aluminum wire anodizing and process

    A high speed aluminum wire anodizing machine and process are provided which includes anodizing aluminum wire in an anodizer tank having wire ingress and egress openings. At least two adjacent rotatable wire accumulator drums are provided in the tank, preferably with means for producing a flow of anodizing electrolytes into each of the drums through an end hub thereof and out of the sidewalls of the drums passed circumferential wire separators. An anode is located proximal to the wire ingress opening, preferably in a contact cell which has an adjustable wire egress window. At least one cathode is provided in the tank. The cathode is preferably either between the drums or a pair of cathodes are provided above and below the drums adjacent to the sidewalls thereof, or both

  1. Monetary policy and dynamic adjustment of corporate investment: A policy transmission channel perspective

    Qiang; Fu; Xing; Liu

    2015-01-01

    We investigate monetary policy effects on corporate investment adjustment,using a sample of China’s A-share listed firms(2005–2012), under an asymmetic framework and from a monetary policy transmission channel perspective. We find that corporate investment adjustment is faster in expansionary than contractionary monetary policy periods. Monetary policy has a significant effect on adjustment speed through monetary and credit channels. An increase in the growth rate of money supply or credit accelerates adjustment.Both effects are significantly greater during tightening than expansionary periods. The monetary channel has significant asymmetry, whereas the credit channel has none. Leverage moderates the relationship between monetary policy and adjustment, with a greater effect in expansionary periods. This study enriches the corporate investment behavior literature and can help governments develop and optimize macro-control policies.

  2. Adjustable extender for instrument module

    A blank extender module used to mount an instrument module in front of its console for repair or test purposes has been equipped with a rotatable mount and means for locking the mount at various angles of rotation for easy accessibility. The rotatable mount includes a horizontal conduit supported by bearings within the blank module. The conduit is spring-biased in a retracted position within the blank module and in this position a small gear mounted on the conduit periphery is locked by a fixed pawl. The conduit and instrument mount can be pulled into an extended position with the gear clearing the pawl to permit rotation and adjustment of the instrument

  3. Focal Adjustment for Star Tracker

    Liu Hai-bo

    2010-10-01

    Full Text Available Technique of measuring intensity distribution and size of spot image developed has been discussed, which is especially suitable for defocus adjustment in ground test of star tracker. A novel approach for choosing a proper defocusing position has been proposed based on collimator, Gaussian surface fitting method, and other ordinary instruments. It proves to be practical and adequate in the development of distant object tracking such as star tracker.Defence Science Journal, 2010, 60(6, pp.678-682, DOI:http://dx.doi.org/10.14429/dsj.60.36

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

    孙坚; 王君艳

    2012-01-01

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

  5. High-Speed Schlieren Movies of Decelerators at Supersonic Speeds

    1960-01-01

    High-Speed Schlieren Movies of Decelerators at Supersonic Speeds. Tests were conducted on several types of porous parachutes, a paraglider, and a simulated retrorocket. Mach numbers ranged from 1.8-3.0, porosity from 20-80 percent, and camera speeds from 1680-3000 feet per second (fps) in trials with porous parachutes. Trials of reefed parachutes were conducted at Mach number 2.0 and reefing of 12-33 percent at camera speeds of 600 fps. A flexible parachute with an inflatable ring in the periphery of the canopy was tested at Reynolds number 750,000 per foot, Mach number 2.85, porosity of 28 percent, and camera speed of 36oo fps. A vortex-ring parachute was tested at Mach number 2.2 and camera speed of 3000 fps. The paraglider, with a sweepback of 45 degrees at an angle of attack of 45 degrees was tested at Mach number 2.65, drag coefficient of 0.200, and lift coefficient of 0.278 at a camera speed of 600 fps. A cold air jet exhausting upstream from the center of a bluff body was used to simulate a retrorocket. The free-stream Mach number was 2.0, free-stream dynamic pressure was 620 lb/sq ft, jet-exit static pressure ratio was 10.9, and camera speed was 600 fps. [Entire movie available on DVD from CASI as Doc ID 20070030973. Contact help@sti.nasa.gov

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

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

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

    Ibekwe B.E

    2014-10-01

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

  8. Keratinocyte galvanotaxis in combined DC and AC electric fields supports an electromechanical transduction sensing mechanism.

    Hart, Francis X; Laird, Mhairi; Riding, Aimie; Pullar, Christine E

    2013-02-01

    Sedentary keratinocytes at the edge of a skin wound migrate into the wound, guided by the generation of an endogenous electric field (EF) generated by the collapse of the transepithelial potential. The center of the wound quickly becomes more negative than the surrounding tissue and remains the cathode of the endogenous EF until the wound is completely re-epithelialized. This endogenous guidance cue can be studied in vitro. When placed in a direct current (DC) EF of physiological strength, 100 V/m, keratinocytes migrate directionally toward the cathode in a process known as galvanotaxis. Although a number of membrane-bound (e.g., epidermal growth factor receptor (EGFR), integrins) and cytosolic proteins (cAMP, ERK, PI3K) are known to play a role in the downstream signaling mechanisms underpinning galvanotaxis, the initial sensing mechanism for this response is not understood. To investigate the EF sensor, we studied the migration of keratinocytes in a DC EF of 100 V/m, alternating current (AC) EFs of 40 V/m at either 1.6 or 160 Hz, and combinations of DC and AC EFs. In the AC EFs alone, keratinocytes migrated randomly. The 1.6 Hz AC EF combined with the DC EF suppressed the direction of migration but had no effect on speed. In contrast, the 160 Hz AC EF combined with the DC EF did not affect the direction of migration but increased the migration speed compared to the DC EF alone. These results can be understood in terms of an electromechanical transduction model, but not an electrodiffusion/osmosis or a voltage-gated channel model. PMID:22907479

  9. A computerized adjustable brain atlas

    A computerized brain atlas, adjustable to the patients anatomy, has been developed. It is primarily intended for use in positron emission tomography, but may also be employed in other fields utilizing neuro imaging, such as sterotactic surgery, transmission computerized tomography (CT) and magnetic resonance imaging (MRI). The atlas is based on anatomical information obtained from digitized cryosectioned brains. It can be adjusted to fit a wide range of images from individual brains with normal anatomy. The corresponding transformation is chosen so that the modified atlas agrees with a set of CT or NMR images of the patient. The computerized atlas can be used to improve the quantification and evaluation of PET data by: Aiding and improving the selection of regions of interests. Facilitating comparisons of functional image data from different individuals or groups of individuals. Facilitating the comparison of different examinations of the same patient, thus reducing the need of reproducible fixation systems. Providing external a priori anatomical information to be used in the image reconstruction. Improving the attenuation and scatter corrections. Aiding in selecting a suitable patient orientation during the PET study. By applying the inverse atlas transformation to PET data set it is possible to relate the PET information to the anatomy of the reference atlas. Reformatted PET data from different patients can thus be averaged, and averages from different categories of patients can be compared. The method will facilitate the identification of statistically significant differences in the PET information from different groups of patients. (orig.)

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

    Marian GAICEANU; Emil ROSU

    2003-01-01

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

  11. Transport AC losses in YBCO coated conductors

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

    2007-09-15

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

  12. Models of Speed Discrimination

    1997-01-01

    visual search for the detection of speed deviation. 2. Perception of moving objects. 3. Exploring the role of eye movements in various visual tasks.

  13. 48 CFR 1450.103 - Contract adjustments.

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract adjustments. 1450.103 Section 1450.103 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR CONTRACT... Contract adjustments....

  14. Speed control system of IC engine of series hybrid electric

    Xiaodong, H; Tian, G.; Zhu, Y.; Chen, Q.; Fu, C. [Tsinghua Univ., Beijing (China). Dept. of Automotive Engineering; State Key Lab. of Automotive Safety and Energy, Beijing (China)

    2000-07-01

    Hybrid electric vehicles (HEV) are an ideal transitional product in the near future. The means by which to achieve low levels of fuel consumption and vehicle emission in an HEV is the speed control system of an internal combustion (IC) engine. The optimization of this complex, large inertia and non-linear time-varying system is difficult to resolve through conventional mathematical models. The authors applied single neural cell adaptive control to set up the optimization target of the engine speed control system of a series of hybrid electric bus. The parameters of PID adjuster of the feedback control system, which is a double closed loops control system had to be designed first, followed by the design of the parameters of the feedforward control system. The method was implemented with Philips-80C552 and bench tests showed that the method yields an effective engine speed control. refs., figs.

  15. LC-filter Resonance Cancellation with DPWM Inverters in Adjustable Speed Drives

    Vadstrup, Casper; Wang, Xiongfei; Blaabjerg, Frede

    2015-01-01

    inverter and filter. Instead of abruptly clamp in one of the inverter legs and cause resonance in the filter. This method will charge or discharge the filter capacitor before clamping, this way the capacitor current is zero, and the capacitor voltage is equal to the average inverter voltage. Thereby, no...

  16. UNEMPLOYMENT AND SPEED OF ADJUSTMENT IN ASEAN-3 ECONOMIES: A COINTEGRATION ANALYSIS

    THIRUNAUKARASU SUBRAMANIAM; AHMAD ZUBAIDI BAHARUMSHAH

    2011-01-01

    This paper investigates the existence of long-run relationship between unemployment and several key macroeconomic variables in Malaysia, Singapore, and the Philippines. The Johansen–Juselius cointegration method confirms the existence of a stationary long-run cointegration relationship between unemployment and its determinants in all three countries. Exports and foreign direct investment are important determinants of unemployment in Malaysia. In the Philippines, government spending and export...

  17. DUAL THREE-PHASE ADJUSTABLE SPEED DRIVE WITH SYNCHRONIZED SPACE-VECTOR MODULATION

    Oleschuk V.I.

    2008-04-01

    Full Text Available Split-phase symmetrical motor drive on the base of two voltage source inverters, controlled by algorithms of synchronized pulse width modulation (PWM, has been investigated. Simulation results are presented for dual three-phase power conversion systems with continuous, discontinuous and combined versions of synchronized PWM.

  18. Two Switch Adjustable-Speed Drive with Single-Phase Induction Machine

    Chomát, Miroslav; Lipo, T.

    Blacksburg, VA: National Science Foundation Engineering research Center, 2000, s. 381-385. [2000 CPES Power Electronics Seminar at Virginia Tech. Blacksburg, VA (US), 17.09.2000-19.09.2000] R&D Projects: GA MŠk ME 332 Grant ostatní: NSF(US) 9820434 Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  19. DUAL THREE-PHASE ADJUSTABLE SPEED DRIVE WITH SYNCHRONIZED SPACE-VECTOR MODULATION

    Oleschuk V.I.; Prudeak R.; Sizov A.S.; Iaroshenco E.M.

    2008-01-01

    Split-phase symmetrical motor drive on the base of two voltage source inverters, controlled by algorithms of synchronized pulse width modulation (PWM), has been investigated. Simulation results are presented for dual three-phase power conversion systems with continuous, discontinuous and combined versions of synchronized PWM.

  20. Labour Adjustment Costs and British Footwear Protection

    Winters, L. Alan

    1990-01-01

    Import protection is frequently advocated as a means of preserving jobs and avoiding labour adjustment costs. Defining adjustment costs in terms of output forgone during the process of adjustment and ignoring any general equilibrium repercussions, we estimate that quantitative restrictions on British footwear imports during 1979 protected about 1,000 jobs and avoided once-and-for-all adjustment costs of only around 1 million pounds sterling. The result is based on new data which reveal high r...

  1. Anchoring Adjusted Capital Asset Pricing Model

    Hammad, Siddiqi

    2015-01-01

    An anchoring adjusted Capital Asset Pricing Model (ACAPM) is developed in which the payoff volatilities of well-established stocks are used as starting points that are adjusted to form volatility judgments about other stocks. Anchoring heuristic implies that such adjustments are typically insufficient. ACAPM converges to CAPM with correct adjustment, so CAPM is a special case of ACAPM. The model provides a unified explanation for the size, value, and momentum effects in the stock market. A ke...

  2. Voltage-sharing Characteristics of Porcelain Insulators for 750 kV AC Substation%Voltage-sharing Characteristics of Porcelain Insulators for 750 kV AC Substation

    ZHANG Shi-ting; PENG Zong-ren; LIAO Jin tao

    2011-01-01

    Considering the complex environment in 750 kV AC substation, porcelain insulators have particular electric field and voltage distribution in comparison with those used in AC transmission line, meanwhile, the investigation of a typical 750 kV AC substation located in Lanzhou with ultraviolet imager (UVI) demonstrated that the corona dis- charge of some insulators is serious due to the improper structure design and installation, so research on porcelain insulators used in substation is needed. The three-dimensional finite element method (FEM) 750 kV AC substation calculation model was established to calculate electric field and voltage distribution of insulators, and the voltage distribution curves along insulators which are classified by type and suspension location were obtained using a novel FEM method which can effectively reduce the calculation amount without losing accuracy, meanwhile, the effect of the grading ring for improving voltage distribution of insulators was studied by adjusting the structure parameters of grad- ing ring. Consequently, an optimization structure of rings was proposed by improving the voltage distribution of insu- lator string and reducing the electric strength of grading ring for the purpose of restricting corona noise, and the on- site observations by UVI showed that the newly manufactured and installed grading ring could obviously avoid the occurrences of corona discharge which validates the optimization design. This paper proposed an effective method combi ning UVI observation and FEM calculation to study voltage-sharing characteristics of porcelain insulators, and the results can provide experiences and references for the design of 750 kV AC substation.

  3. Power Quality Control and Design of Power Converter for Variable-Speed Wind Energy Conversion System with Permanent-Magnet Synchronous Generator

    Yüksel Oğuz

    2013-01-01

    Full Text Available The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%.

  4. Power quality control and design of power converter for variable-speed wind energy conversion system with permanent-magnet synchronous generator.

    Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin

    2013-01-01

    The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%. PMID:24453905

  5. How to Improve Reading Speed

    王仲亮

    2008-01-01

    @@ It is well known that reading plays an important role not only in our daily life but also in learning a foreign language.And,of course,reading depends on reading speed to some degree.So it is natural that it is important to improve reading speed.

  6. When is speed a problem?.

    Wesemann, P.

    1986-01-01

    It is relatively useless to make pronouncements on what, in certain circumstances, is a safe driving speed for road users; it is interesting, however, to indicate what is an optimum speed from the social point of view, after weighing up the various pros and cons, including safety. Ultimately this is

  7. NTF – wind speed comparison

    Vesth, Allan; Gómez Arranz, Paula

    The report describes measurements carried out on a given turbine. A comparison between wind speed on the met mast and Nacelle Wind speed are made and the results are presented on graphs and in a table. The data used for the comparison are the data that are same as used for the power curve report...

  8. High Speed Viterbi Decoder Architecture

    Paaske, Erik; Andersen, Jakob Dahl

    1998-01-01

    The fastest commercially available Viterbi decoders for the (171,133) standard rate 1/2 code operate with a decoding speed of 40-50 Mbit/s (net data rate). In this paper we present a suitable architecture for decoders operating with decoding speeds of 150-300 Mbit/s....

  9. Optimal Speed Control for Cruising

    Blanke, M.

    1994-01-01

    With small profit margins in merchant shipping and more than eighty percent of sailing time being cross ocean voyages, speed control is crucial for vessel profitability......With small profit margins in merchant shipping and more than eighty percent of sailing time being cross ocean voyages, speed control is crucial for vessel profitability...

  10. Speed control of diesel generator sets

    In some marine and stationary power plants, it is often of interest to be able to give some information about the dynamic behaviour of the engine when it is loaded according to a given programme: How well it reacts to the application of a step load and to a load rejection. What is the best speed governor type and its optimum parameter adjustment in order to satisfy the requested specification of maximum speed engine deviation and recovery time. How great is the influence of turbocharger options such as jet assist or waste gate on the dynamic behaviour of the plant. Such kinds of questions occur for all stand-by power stations and in marine installations where the engine is submitted to very large load variations in the form of steps, ramps or any other load programme. The computer program GENERAT fully fulfils the aims described above. The comparison of measurements and simulation is good enough to allow us to use simulation as a means of predicting the dynamic behaviour of stationary power plant with four-stroke engines submitted to a given load programme. This program allows us also to determine the optimum generator inertia and to find the optimum governor parameters. The next step of development will be to model the turbocharger and supercharging method for two-stroke engines and some new digital speed controls and to rewrite the program with the help of the simulation package ACSL. This last point presents some advantages, as for example in large reduction of program maintenance and higher flexibility

  11. 高频斩波串级调速系统功率因数的分析与计算%Analysis and Calculation for Power Factor of the High-frequency Chopped Wave Cascade Speed Control Drive System

    张军伟; 王兵树; 万军; 甄亚

    2011-01-01

    相对于变频调速系统,高频斩波串级调速系统具有节能效率高、结构简单、技术难度小等优点,在交流调速中得到了广泛应用.但和传统串级调速一样,该系统的严重缺点之一是功率因数低,而且随着负载变化和速度的调节,系统功率因数的变化范围很大.所以有必要准确分析计算其功率因数.本文介绍了高频斩波串级调速系统的工作原理,在此基础上提出了一种新的计算高频斩波串级调速系统功率因数的简化算法,总结了影响高频斩波串级调速系统功率因数的几大因素,最后通过建立试验系统进行验证,证实该算法的可靠性,对实际工程设计有实用价值.%Compared with frequency conversion speed control, high-frequency chopped wave cascade speed control drive system has such advantages as good efficiency on energy saving, simple structure and little technical difficulty,etc. So, it is widely used in AC governing speed field. However, as the traditional cascade speed governing drive, low power factor is the same overt weakness to the high-frequency chopped wave cascade speed control drive system. In addition, the power factor could change in a large range with the speed adjustment and changing load. So it is very necessary to analyse and calculate the power factor accurately. A compact algorithm to calculate the power factor of chopped wave cascade speed control drive system is put forward on the basic of introduction of the radical theory about it. A few of factors impacting on the power factor of chopper cascade speed control drive system are summed up. At last, A simulation validating system is founded, and which prove that the algorithm is reliable and practical on engineering design.

  12. 12 CFR 1780.80 - Inflation adjustments.

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Inflation adjustments. 1780.80 Section 1780.80... DEVELOPMENT RULES OF PRACTICE AND PROCEDURE RULES OF PRACTICE AND PROCEDURE Civil Money Penalty Inflation Adjustments § 1780.80 Inflation adjustments. The maximum amount of each civil money penalty within...

  13. Dimensions of Adjustment among College Women.

    Tomlinson-Clarke, Saundra

    1998-01-01

    Examines academic, social, and personal-emotional adjustment, as well as institutional attachment for women (N=198) attending a predominantly white coeducational research university. Significant main effects were found on academic achievement for year in college. Students differed on personal-emotional adjustment by race. Academic adjustment and…

  14. The need for speed: global optic flow speed influences steering.

    Kountouriotis, Georgios K; Mole, Callum D; Merat, Natasha; Wilkie, Richard M

    2016-05-01

    How do animals follow demarcated paths? Different species are sensitive to optic flow and one control solution is to maintain the balance of flow symmetry across visual fields; however, it is unclear whether animals are sensitive to changes in asymmetries when steering along curved paths. Flow asymmetries can alter the global properties of flow (i.e. flow speed) which may also influence steering control. We tested humans steering curved paths in a virtual environment. The scene was manipulated so that the ground plane to either side of the demarcated path produced larger or smaller asymmetries in optic flow. Independent of asymmetries and the locomotor speed, the scene properties were altered to produce either faster or slower globally averaged flow speeds. Results showed that rather than being influenced by changes in flow asymmetry, steering responded to global flow speed. We conclude that the human brain performs global averaging of flow speed from across the scene and uses this signal as an input for steering control. This finding is surprising since the demarcated path provided sufficient information to steer, whereas global flow speed (by itself) did not. To explain these findings, existing models of steering must be modified to include a new perceptual variable: namely global optic flow speed. PMID:27293789

  15. Neighborhood Assets and Adolescent Adjustment

    Alfredo Oliva Delgado

    2011-12-01

    Full Text Available This paper presents the results of a study analyzing the relationship between some dimensions or developmental assets in the neighborhood, as measured by the Scale for the Assessment of Developmental Assets in the Neighborhood, and adjustment and life satisfaction of adolescent boys and girls. The sample consisted of 2400 adolescents (1068 boys and 1332 girls between ages 12 and 17 who were secondary students in public and private schools in Western Andalusia. The results showed significant relationships between most dimensions of the scale (youth empowerment, attachment to neighbourhood safety and social control and internalizing and externalizing problems, substance use and life satisfaction of participants. Moreover, the data provide evidence about the external validity of the scale used in the study. From the results some suggestions for intervention in the community environment are extracted.

  16. Culture, emotion regulation, and adjustment.

    Matsumoto, David; Yoo, Seung Hee; Nakagawa, Sanae

    2008-06-01

    This article reports differences across 23 countries on 2 processes of emotion regulation--reappraisal and suppression. Cultural dimensions were correlated with country means on both and the relationship between them. Cultures that emphasized the maintenance of social order--that is, those that were long-term oriented and valued embeddedness and hierarchy--tended to have higher scores on suppression, and reappraisal and suppression tended to be positively correlated. In contrast, cultures that minimized the maintenance of social order and valued individual Affective Autonomy and Egalitarianism tended to have lower scores on Suppression, and Reappraisal and Suppression tended to be negatively correlated. Moreover, country-level emotion regulation was significantly correlated with country-level indices of both positive and negative adjustment. PMID:18505309

  17. A Study on the Effects of Compression Ratio, Engine Speed and Equivalence Ratio on HCCI Combustion of DME

    Pedersen, Troels Dyhr; Schramm, Jesper

    2007-01-01

    adjusted in steps to find suitable regions of operation, and the effect of engine speed was studied at 1000, 2000 and 3000 RPM. It was found that leaner excess air ratios require higher compression ratios to achieve satisfactory combustion. Engine speed also affects operation significantly....

  18. Dynamic adjustment in agricultural practices to economic incentives aiming to decrease fertilizer application.

    Sun, Shanxia; Delgado, Michael S; Sesmero, Juan P

    2016-07-15

    Input- and output-based economic policies designed to reduce water pollution from fertilizer runoff by adjusting management practices are theoretically justified and well-understood. Yet, in practice, adjustment in fertilizer application or land allocation may be sluggish. We provide practical guidance for policymakers regarding the relative magnitude and speed of adjustment of input- and output-based policies. Through a dynamic dual model of corn production that takes fertilizer as one of several production inputs, we measure the short- and long-term effects of policies that affect the relative prices of inputs and outputs through the short- and long-term price elasticities of fertilizer application, and also the total time required for different policies to affect fertilizer application through the adjustment rates of capital and land. These estimates allow us to compare input- and output-based policies based on their relative cost-effectiveness. Using data from Indiana and Illinois, we find that input-based policies are more cost-effective than their output-based counterparts in achieving a target reduction in fertilizer application. We show that input- and output-based policies yield adjustment in fertilizer application at the same speed, and that most of the adjustment takes place in the short-term. PMID:27100331

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

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

    2008-01-01

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

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

    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.

  1. Proposed torque optimized behavior for digital speed control of induction motors

    Metwally, H.M.B.; El-Shewy, H.M.; El-Kholy, M.M. [Zagazig Univ., Dept. of Electrical Engineering, Zagazig (Egypt); Abdel-Kader, F.E. [Menoufyia Univ., Dept. of Electrical Engineering, Menoufyia (Egypt)

    2002-09-01

    In this paper, a control strategy for speed control of induction motors with field orientation is proposed. The proposed method adjusts the output voltage and frequency of the converter to operate the motor at the desired speed with maximum torque per ampere at all load torques keeping the torque angle equal to 90 deg. A comparison between the performance characteristics of a 2 hp induction motor using three methods of speed control is presented. These methods are the proposed method, the direct torque control method and the constant V/f method. The comparison showed that better performance characteristics are obtained using the proposed speed control strategy. A computer program, based on this method, is developed. Starting from the motor parameters, the program calculates a data set for the stator voltage and frequency required to obtain maximum torque per ampere at any motor speed and load torque. This data set can be used by the digital speed control system of induction motors. (Author)

  2. Resonant frequency detection and adjustment method for a capacitive transducer with differential transformer bridge

    Hu, M.; Bai, Y. Z., E-mail: abai@mail.hust.edu.cn; Zhou, Z. B., E-mail: zhouzb@mail.hust.edu.cn; Li, Z. X.; Luo, J. [MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-05-15

    The capacitive transducer with differential transformer bridge is widely used in ultra-sensitive space accelerometers due to their simple structure and high resolution. In this paper, the front-end electronics of an inductive-capacitive resonant bridge transducer is analyzed. The analysis result shows that the performance of this transducer depends upon the case that the AC pumping frequency operates at the resonance point of the inductive-capacitive bridge. The effect of possible mismatch between the AC pumping frequency and the actual resonant frequency is discussed, and the theoretical analysis indicates that the output voltage noise of the front-end electronics will deteriorate by a factor of about 3 due to either a 5% variation of the AC pumping frequency or a 10% variation of the tuning capacitance. A pre-scanning method to determine the actual resonant frequency is proposed followed by the adjustment of the operating frequency or the change of the tuning capacitance in order to maintain expected high resolution level. An experiment to verify the mismatching effect and the adjustment method is provided.

  3. Resonant frequency detection and adjustment method for a capacitive transducer with differential transformer bridge

    Hu, M.; Bai, Y. Z.; Zhou, Z. B.; Li, Z. X.; Luo, J.

    2014-05-01

    The capacitive transducer with differential transformer bridge is widely used in ultra-sensitive space accelerometers due to their simple structure and high resolution. In this paper, the front-end electronics of an inductive-capacitive resonant bridge transducer is analyzed. The analysis result shows that the performance of this transducer depends upon the case that the AC pumping frequency operates at the resonance point of the inductive-capacitive bridge. The effect of possible mismatch between the AC pumping frequency and the actual resonant frequency is discussed, and the theoretical analysis indicates that the output voltage noise of the front-end electronics will deteriorate by a factor of about 3 due to either a 5% variation of the AC pumping frequency or a 10% variation of the tuning capacitance. A pre-scanning method to determine the actual resonant frequency is proposed followed by the adjustment of the operating frequency or the change of the tuning capacitance in order to maintain expected high resolution level. An experiment to verify the mismatching effect and the adjustment method is provided.

  4. Application of direct torque control to electric screw presses for speeding up torque response and reducing starting current

    FENG Yi; HUANG Shu-huai; LI Jun-chao; XIONG Xiao-hong

    2009-01-01

    Fast response and stable torque output are crucial to the performance of electric screw presses. This paper describes the design of a direct torque control (DTC) system for speeding up torque response and reducing the starting current of electric screw presses and its application to the J58K series of numerical control electric screw presses with a dual-motor drive. The DTC drive system encompasses speed control, torque reference control, and switching frequency control. Comparison of the DTC duaI-AC induction motor drive with corresponding AC servo motor drive showed that for the J58K-315 electric screw press, the DTC drive system attains a higher maximum speed (786 r/min) within a shorter time (1.13 s) during a 250 mm stroke and undergoes smaller rise in temperature (42.0 ℃) in the motor after running for 2 h at a 12 min strike fi'equency than the AC servo motor drive does (751 r/min within 1.19 s, and 50.6 ℃ rise). Moreover, the DTC AC induction motor drive, with no need for a tachometer or position encoder to feed back the speed or position of the motor shaft, enjoys increased reliability in a strong-shock work environment.

  5. Pay as You Speed, ISA with incentives for not speeding

    Lahrmann, Harry Spaabæk; Agerholm, Niels; Tradisauskas, Nerius;

    2012-01-01

    the reduction of a 30% discount on the driver's car insurance premium, which therefore produced the name, Pay as You Speed. The ISA equipment consists of a GPS-based On Board Unit with a mobile phone connection to a web server. The project was planned for a three-year test period with 300 young car drivers......, but it never succeeded in recruiting that number of drivers. After several design changes, the project eventually went forward with 153 test drivers of all ages. This number represents approximately one thousandth of all car owners in the proving ground of North Jutland in Denmark. Furthermore the project......The Intelligent Speed Adaptation (ISA) project we describe in this article is based on Pay as You Drive principles. These principles assume that the ISA equipment informs a driver of the speed limit, warns the driver when speeding and calculates penalty points. Each penalty point entails...

  6. CHANGES IN RUNNING SPEEDS IN A 100 KM ULTRA-MARATHON RACE

    Miriam R. Waldeck

    2004-09-01

    Full Text Available The purpose of this study was to determine if runners who completed a 100 km ultramarathon race in the fastest times changed their running speeds differently compared to those runners who ran an overall slower race. Times were taken from the race results of the 1995 100 km IAU World Challenge in Winschoten, Netherlands. Race times and 10 km split times were analyzed. Runners (n = 67 were divided into groups of ten with the last group consisting of seven runners. The mean running speed for each 10 km segment was calculated using each runner's 10 km split times. Mean running speed was calculated using each runner's race time. The first 10 km split time was normalized to 100, with all subsequent times adjusted accordingly. The mean running speed for each group at each 10 km split was then calculated. The faster runners started at a faster running speed, finished the race within 15 % of their starting speed, and maintained their starting speed for longer (approximately 50 km before slowing. The slower runners showed a greater percentage decrease in their mean running speed, and were unable to maintain their initial pace for as long. It is concluded that the faster runners: 1 ran with fewer changes in speed, 2 started the race at a faster running speed than the slower runners, and 3 were able to maintain their initial speed for a longer distance before slowing

  7. AC losses in filamentary YBCO/hastelloy

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

  8. Effect of wind speed on accuracy of Turc method in a humid climate

    Trajković Slaviša; Stojnić Vladimir

    2007-01-01

    The Turc method is one of the simplest and most accurate empirical equations used for ETO estimation. The objectives of this study are: first, to investigate the effect of wind speed on accuracy of Turc method; second, to develop the wind speed adjustment factors for the Turc method. The adjusted Turc method provides the quite good agreement with the evapotranspiration obtained by the FAO-56 Penman-Monteith method. It gave reliable estimation at all the locations and it has proven to be the m...

  9. To the Problem of Electromechanical Interaction in Elevators with Controlled Electric Drive and Fuzzy Speed Controller

    A. S. Koval

    2010-01-01

    Full Text Available The paper considers problems concerning electromechanical interaction in elevators with an adjustable asynchronous electric drive equipped with the vector control systems under direct torque control and direct torque control with pulse-width modulator. A mathematical description of electromechanical elevator system with due account of nonlinearity of the worm gear is given in the paper. The paper presents a simplified circuit design of a control system with a fuzzy speed controller. It has been established that the factor of electromechanical interaction in electromechanical system with the adjustable asynchronous electric drive and an fuzzy speed controller is within the range which corresponds to existence of the essential electromechanical interaction.

  10. Flow Control Strategy for the High Speed Network Based on Control Theory

    2002-01-01

    Design of an effective congestion control scheme is a hot topic in the development of computer network. The flow control scheme can adjust the packet sending rate in source host, thus effectively avoiding the network congestion. This paper proposes a new flow control scheme based on discrete control theory. The simulation results show that this method can adjust the sending rate and queue level in buffer rapidly and effectively. The method is easy to implement and applicable to high speed networks.

  11. Demonstration of variable speed permanent magnet generator at small, low-head hydro site

    Brown Kinloch, David [Shaker Landing Hydro Associates, Inc., Louisville, KY (United States)

    2015-12-18

    Small hydro developers face a limited set of bad choices when choosing a generator for a small low-head hydro site. Direct drive synchronous generators are expensive and technically complex to install. Simpler induction generators are higher speed, requiring a speed increaser, which results in inefficiencies and maintenance problems. In addition, both induction and synchronous generators turn at a fixed speed, causing the turbine to run off its peak efficiency curve whenever the available head is different than the designed optimum head.The solution to these problems is the variable speed Permanent Magnet Generators (PMG). At the Weisenberger Mill in Midway, KY, a variable speed Permanent Magnet Generator has been installed and demonstrated. This new PMG system replaced an existing induction generator that had a HTD belt drive speed increaser system. Data was taken from the old generator before it was removed and compared to data collected after the PMG system was installed. The new variable speed PMG system is calculated to produce over 96% more energy than the old induction generator system during an average year. This significant increase was primarily due to the PMG generator operating at the correct speed at the maximum head, and the ability for the PMG generator to reduce its speed to lower optimum speeds as the stream flow increased and the net head decreased.This demonstration showed the importance of being able to adjust the speed of fixed blade turbines. All fixed blade turbines with varying net heads could achieve higher efficiencies if the speed can be matched to the optimum speed as the head changes. In addition, this demonstration showed that there are many potential efficiencies that could be realized with variable speed technology at hydro sites where mismatched turbine and generator speeds result in lower power output, even at maximum head. Funding for this project came from the US Dept. of Energy, through Award Number DE-EE0005429.

  12. Variable Speed Wind Turbine Based on Multiple Generators Drive-Train Configuration

    Deng, Fujin; Chen, Zhe

    2010-01-01

    A variable speed wind turbine is presented in this paper, where multiple permanent magnet synchronous generators (MPMSGs) drive-train configuration is employed in the wind turbine. A cascaded multilevel converter interface based on the MPMSGs is developed to synthesize a desired high ac sinusoidal...... reduce the fluctuation of the electromagnetic torque sum and results in a good performance for the MPMSGs structure. The simulation study is conducted using PSCAD/EMTDC, and the results verify the feasibility of this variable speed wind turbine based on multiple generators drive-train configuration....... output voltage, which could be directly connected to the grids. What is more, such arrangement has been made so that the output ac voltage having a selected phase angle difference among the stator windings of multiple generators. A phase angle shift strategy is proposed in this paper, which effectively...

  13. A New Structure Based on Cascaded Multilevel Converter for Variable Speed Wind Turbine

    Deng, Fujin; Chen, Zhe

    2010-01-01

    An alternative structure for variable speed wind turbine, using multiple permanent magnet synchronous generators (PMSGs) drive-train configuration and cascaded multilevel converter is proposed in this paper. This study presents a power electronic solution for the wind turbine. A transformer...... simulation model of 10 MW variable speed wind turbine based on PMSGs developed in PSCAD/EMTDC is presented. The dynamic performance of grid-connected wind turbine is analyzed. Simulation results shows that the proposed structure may be attractive in wind power generation.......-less cascaded multilevel converter interface based on PMSGs is developed to synthesize a desired high ac sinusoidal output voltage. The benefits of high power and high ac voltage make this structure possible to be applied in the wind power generation. In addition, the bulky transformer could be omitted. A...

  14. Efficient Disengaging Hooks System Based on Constant-Power Speed Regulation of Frequency Converter

    Jianjian Wang

    2013-04-01

    Full Text Available In the traditional port, disengaging hook system adopts a three-phase power frequency power to drive a three-phase asynchronous motor. The operation is simple and the maintenance is convenient. However, it still keeps the speed of mooring lines constant. Under the light-load condition, the work efficiency could be affected because of the low speed. To solve this problem, we start the research in speed control of disengaging hook. By using variable frequency control technology to transform the original system and using frequency converter to carry on the constant-power speed regulation, technicians also adopt vector control algorithm with PG to achieve adjustable speed of cable volume. The motor is under no load or light load state with high-speed after starting and turns into low-speed through full load. It makes motor stay in constant-power state when it works. This design solves the low-efficiency of disengaging hook in the past and makes system achieve adjustable motor speed. In this design and application, not only can technicians reduce the initial cost, but also they can reduce operating costs markedly by adopting energy-saving control equipment at the same time.

  15. Speed Control of Induction Motor Using PLC and SCADA System

    Ayman Seksak Elsaid,

    2016-01-01

    Full Text Available Automation or automatic control is the use of various control systems for operating equipment such as machinery, processes in factories, boilers and heat-treating ovens, switching in telephone networks, steering and stabilization of ships, aircraft and other applications with minimal or reduced human intervention. Some processes have been completely automated. The motor speed is controlled via the driver as an open loop control. To make a more precise closed loop control of motor speed we will use a tachometer to measure the speed and feed it back to the PLC, which compares to the desired value and take a control action, then the signal is transferred to the motor – via driver – to increase / decrease the speed. We will measure the speed of the motor using an incremental rotary encoder by adjusting parameters (PLC, driver and also we need to reduce the overall cost of the system. Our control system will be held using the available Siemens PLC. In addition, we will monitor motor parameters via SCADA system.

  16. THERMAL ANALYSIS OF FRICTIONAL DISK IN SPEEDING WET CLUTCH

    Hong Yue; Liu Jin; Wang Yungeng

    2004-01-01

    Multi-frictional disks are employed to transmit the torque in speeding wet clutch, and the oil thickness within frictional disks could be adjusted for practical output speeding.As oil combined with α-hydrocarbon or polyester is getting widely used as lubricant and the speeding wet clutch works within hydrodynamic lubrication, mixture lubrication, boundary lubrication and contact situation, established the thermal analysis model for investigating the behavior of frictional disks in speeding wet clutch, which covers the power-law fluid model, Patir-Cheng average flow model, GT asperity contact model, oil film inertia and heat effects, mean energy equation, and heat conduction equation.The formulas in the model are deduced.The numeral calculation and analysis for hydrodynamic lubrication and mixture lubrication are executed.Relationships and variations among transmitting torque, mean push pressure, output speed, and load are presented.Thermal effect should be considered during the hydrodynamic lubrication and larger transmitting torque makes earlier entrance to mixture lubrication.

  17. Forecasting wind speed financial return

    D'Amico, Guglielmo; Prattico, Flavio

    2013-01-01

    The prediction of wind speed is very important when dealing with the production of energy through wind turbines. In this paper, we show a new nonparametric model, based on semi-Markov chains, to predict wind speed. Particularly we use an indexed semi-Markov model that has been shown to be able to reproduce accurately the statistical behavior of wind speed. The model is used to forecast, one step ahead, wind speed. In order to check the validity of the model we show, as indicator of goodness, the root mean square error and mean absolute error between real data and predicted ones. We also compare our forecasting results with those of a persistence model. At last, we show an application of the model to predict financial indicators like the Internal Rate of Return, Duration and Convexity.

  18. High-Speed Electrochemical Imaging.

    Momotenko, Dmitry; Byers, Joshua C; McKelvey, Kim; Kang, Minkyung; Unwin, Patrick R

    2015-09-22

    The design, development, and application of high-speed scanning electrochemical probe microscopy is reported. The approach allows the acquisition of a series of high-resolution images (typically 1000 pixels μm(-2)) at rates approaching 4 seconds per frame, while collecting up to 8000 image pixels per second, about 1000 times faster than typical imaging speeds used up to now. The focus is on scanning electrochemical cell microscopy (SECCM), but the principles and practicalities are applicable to many electrochemical imaging methods. The versatility of the high-speed scan concept is demonstrated at a variety of substrates, including imaging the electroactivity of a patterned self-assembled monolayer on gold, visualization of chemical reactions occurring at single wall carbon nanotubes, and probing nanoscale electrocatalysts for water splitting. These studies provide movies of spatial variations of electrochemical fluxes as a function of potential and a platform for the further development of high speed scanning with other electrochemical imaging techniques. PMID:26267455

  19. Predictors of Social Mobilization Speed

    Alstott, Jeff; Velu, Chander

    2013-01-01

    Mobilization across social networks is becoming increasingly influential, but little is known about what traits of individuals and their relationships affect their speed of mobilization between them. We ran a global social mobilization contest and recorded personal traits of the participants and those they mobilized. We examined how those traits influenced the speed of mobilization. Individuals mobilized faster when they heard about the contest directly from the contest organization, and decreased in speed when hearing from less personal source types (e.g. family vs. media). Mobilization was faster when the mobilizer and the mobilized heard about the contest through the same source type, and slower when both individuals were in different countries. Females mobilized other females faster than males mobilized other males. Mobilization was faster with young recruiters and old recruits, and slower with old recruiters and young recruits. These findings suggest ways to optimize the speed of social mobilization.

  20. Animal evolution: trilobites on speed.

    Budd, Graham E

    2013-10-01

    A new study quantifies rates of morphological and molecular evolution for arthropods during the critical Cambrian explosion. Both morphological and molecular evolution are accelerated--but not so much to break any speed limits. PMID:24112983

  1. AC loss performance of CS insert coil

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

  2. Factors Influencing Drivers' Speeding Behaviour

    Wallén Warner, Henriette

    2006-01-01

    Every year many people all over the world are killed and severely injured in road traffic accidents. Even though driving too fast is a behaviour well known to contribute to both the number and the outcome of these accidents, drivers are still speeding. The general aim of this thesis, and its five empirical studies, is therefore to further the knowledge about drivers speeding behaviour by using the theory of planned behaviour and the model underpinning the driver behaviour questionnaire as fra...

  3. Operation of new variable speed constant voltage and frequency generator connected to the grid

    Metwally, H.M.B. [Zagazig University, Cairo (Egypt). Faculty of Engineering

    2000-05-01

    Wind is an uncontrolled and stochastic source of power because its speed is continuously changing in magnitude and direction. In order to maximise the obtainable power, wind driven power systems must be able to generate power at all wind speeds whether this speed is low or high. This is not possible when conventional generators are used unless complicated control systems or electronic circuits are used. In this paper, the feasibility of using an AC commutator machine as a generator for wind power plants is experimentally investigated. The machine is connected as a shunt generator in parallel with the grid. It can be operated in a wide range of speeds without any stability problems. Hence, the speed can be controlled such that the maximum output power is obtained at all wind speeds. This type of machine generates a constant frequency voltage irrespective of the shaft speed when excited from a separate constant frequency source. The experimental set has been prepared in the lab such that all variables which affect the generated power can be controlled. These variables include shaft speed, grid coupling voltage and brush angle. The effects of these variables on the amount and quality of power generated are carefully tested. The results obtained show that this machine is a suitable power converter for wind power applications. (author)

  4. 36 CFR 4.21 - Speed limits.

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Speed limits. 4.21 Section 4... TRAFFIC SAFETY § 4.21 Speed limits. (a) Park area speed limits are as follows: (1) 15 miles per hour... superintendent may designate a different speed limit upon any park road when a speed limit set forth in...

  5. Methods of speed measurement. Geschwindigkeitsmessverfahren

    Baeumer, K.; Rath, K.; Rogge, H.; Wiegand, H.

    1990-09-27

    In a method, i.e. the operation of a device for contactless measurement of speeds, speed-time curves and decay frequencies in liquid jets and flames two light beams emitted by strong light source are focussed in such a way in the measured volume of a fluid layer or flame layer that the light transmission in the measured volume can be measured at a focal distance s by means of two light-sensitive detectors. Speeds and speed-time curves in injection jets and flames can be inferred from the shift in time s of the transmission curves by means of the equation v=s/t. Furthermore, the recorded transmission-time curve can be used for harmonic analysis studies by means of a digital Fourier analysis (FFT analysis). The speed v or, as the case may be, the speed-time curve in the layer of a fluid or flame and the frequencies f determined with the frequency spectrum permit a calculation of the wavelength according to the wave equation =vxf, and this in turn determines the ball size in jets of fluid and flames.

  6. Eigenvalues Analysis Applied to the Stability Study of a Variable Speed Pump Turbine Unit

    Han, Michel; Kawkabani, Basile; Simond, Jean-Jacques

    2012-01-01

    This paper presents an eigenvalues analysis method for an induction machine model based on phase variables a, b, c. This approach is validated by comparison with ad, q approach and applied to a variable speed pump-turbine unit using a simplified model of the converters. The proposed approach permits the study and analysis of the interaction between mechanical, electric and regulation parts of the system. Index Terms—control systems, numerical simulation, induction motors, AC-DC power converte...

  7. Sensorless AC electric motor control robust advanced design techniques and applications

    Glumineau, Alain

    2015-01-01

    This monograph shows the reader how to avoid the burdens of sensor cost, reduced internal physical space, and system complexity in the control of AC motors. Many applications fields—electric vehicles, wind- and wave-energy converters and robotics, among them—will benefit. Sensorless AC Electric Motor Control describes the elimination of physical sensors and their replacement with observers, i.e., software sensors. Robustness is introduced to overcome problems associated with the unavoidable imperfection of knowledge of machine parameters—resistance, inertia, and so on—encountered in real systems. The details of a large number of speed- and/or position-sensorless ideas for different types of permanent-magnet synchronous motors and induction motors are presented along with several novel observer designs for electrical machines. Control strategies are developed using high-order, sliding-mode and quasi-continuous-sliding-mode techniques and two types of observer–controller schemes based on backstepping ...

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

    Schwartz, H. J.

    1982-01-01

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

  9. AC loss in superconducting tapes and cables

    Oomen, Marijn Pieter

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

  10. ACS air bearing test-bed design

    Glitt, Sascha

    2010-01-01

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

  11. The Effective AC Response of Nonlinear Composites

    WEI En-Bo; GU Guo-Qing

    2001-01-01

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

  12. YBCO thin films in ac and dc films

    Shahzada, S

    2001-01-01

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

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

    M.A INAYATHULLAAH,

    2010-12-01

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

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

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

    2016-01-01

    The gram-negative bacterium, Gluconacetobacter hansenii, produces cellulose of exceptionally high crystallinity in comparison to the cellulose of higher plants. This bacterial cellulose is synthesized and extruded into the extracellular medium by the cellulose synthase complex (CSC). The catalytic component of this complex is encoded by the gene AcsAB. However, several other genes are known to encode proteins critical to cellulose synthesis and are likely components of the bacterial CSC. We have purified an active heterodimer AcsA-AcsB from G. hansenii ATCC23769 to homogeneity by two different methods. With the purified protein, we have determined how it is post-translationally processed, forming the active heterodimer AcsA-AcsB. Additionally, we have performed steady-state kinetic studies on the AcsA-AcsB complex. Finally through mutagenesis studies, we have explored the roles of the postulated CSC proteins AcsC, AcsD, and CcpAx. PMID:26672449

  15. Efficient Adjustable Reflectivity Smart Window

    D. Morgan Tench

    2005-12-01

    This project addressed the key technical issues for development of an efficient smart window based on reversible electrochemical transfer of silver between a mirror electrode and a localized counter electrode. Effort to provide uniform switching over large areas focused on use of a resistive transparent electrode innerlayer to increase the interelectrode resistance. An effective edge seal was developed in collaboration with adhesive suppliers and an electrochromic device manufacturer. Work to provide a manufacturable counter electrode focused on fabricating a dot matrix electrode without photolithography by electrodeposition of Pt nuclei on inherent active sites on a transparent oxide conductor. An alternative counter electrode based on a conducting polymer and an ionic liquid electrolyte was also investigated. Work in all of these areas was successful. Sputtered large-bandgap oxide innerlayers sandwiched between conductive indium tin oxide (ITO) layers were shown to provide sufficient cross-layer resistance (>300 ohm/cm{sup 2}) without significantly affecting the electrochemical properties of the ITO overlayer. Two edge seal epoxies, one procured from an epoxy manufacturer and one provided by an electrochromic device manufacturer in finished seals, were shown to be effective barriers against oxygen intrusion up to 80 C. The optimum density of nuclei for the dot matrix counter electrode was attained without use of photolithography by electrodeposition from a commercial alkaline platinum plating bath. Silver loss issues for cells with dot matrix electrodes were successfully addressed by purifying the electrolyte and adjusting the cell cycling parameters. More than 30K cycles were demonstrated for a REM cell (30-cm square) with a dot matrix counter electrode. Larger cells (30-cm square) were successfully fabricated but could not be cycled since the nucleation layers (provided by an outside supplier) were defective so that mirror deposits could not be produced.

  16. Trade Liberalization and Trade Adjustment Assistance

    Fung, K. C.; Staiger, Robert W.

    1994-01-01

    We explore the relationship between trade adjustment subsidies and successful reciprocal trade liberalization. We consider economies that are faced with a periodic need to move resources out of a declining import-competing sector, and that are attempting to sustain cooperative but self-enforcing trade agreements in the face of these adjustment needs. If the limitations associated with enforcement of international trade agreements are sufficiently severe, trade adjustment assistance can facili...

  17. Asian immigrant settlement and adjustment in Australia.

    Khoo, S; Kee, P; Dang, T; Shu, J

    1994-01-01

    "This article provides a broad assessment of the settlement and adjustment of people born in the many countries of Asia who are resident in Australia, based on recently available data from the 1991 Census of Population and Housing. It examines some indicators of economic adjustment such as performance in the labor market, and some indicators of social adjustment, such as acquisition of English language proficiency." PMID:12289777

  18. Attitude-adjusting table for neutron monochromator

    The neutron monochromator attitude-adjusting table is one of the mechanical components for most monochromatic neutron scattering spectrometer. It is mainly used for mounting crystal monochromator, and getting monochromatic neutron by adjusting the attitude of monochromator remotely. The table has a compact volume and five adjusting axes with high resolution. It combines optic mechanical electronic technique with computer control technique. This device will be applied to the neutron residual stress spectrometer on CARR firstly. (authors)

  19. Implementation of Risk Adjustment for Medicare

    Ingber, Melvin J.

    2000-01-01

    The Health Care Financing Administration (HCFA) implemented risk adjustment for Medicare capitated organizations January 2000. The risk adjustment system used, the Principal Inpatient Diagnostic Cost Group (PIPDCG) method, had to be incorporated into the payment structure mandated by the Balanced Budget Act of 1997 (BBA). This article describes how risk adjustment was integrated into the payment system within the rules of the BBA, and how fee-for-service (FFS) and health maintenance organizat...

  20. An adjustment cost model of distributional dynamics.

    Getachew, Yoseph; Basu, Parantap

    2012-01-01

    We analyze the distributional e¤ects of adjustment cost in an environment with incomplete capital market. We find that a higher adjustment cost for human capital acquisition slows down the intergenerational mobility and results in a persistent inequality across generations. A low depreciation cost of human capital contributes to longer life of the capital which could elevate this adjustment cost and hence contribute to this inequality persistence. A lower total factor productivity could hurt...

  1. ANALYSIS OF VARIABLE SPEED PFC BUCK–BOOST CONVERTER-FED PMBLDC MOTOR DRIVE

    K. Raghavareddy

    2015-09-01

    Full Text Available This paper presents an analysis of variable speed low power drive with PFC at supply ends by using BLDC PM motor fed from buck-boost converter. The speed control of BLDC achieved by simply control the DC link voltage of VSI converter which is taken as reference signal. This facilitates the operation of VSI at fundamental frequency switching by using the electronic commutation of the BLDC motor which offers reduced switching losses. A PFC buck–boost converter is designed to operate in discontinuous inductor current mode (DICM to provide an inherent PFC at ac mains. The performance of the proposed drive is evaluated over a wide range of speed control and varying supply voltages (universal ac mains at 170–270 V with improved power quality at ac mains. The obtained power quality indices are within the acceptable limits of international power quality standards such as the IEC 61000-3-2. The performance of the proposed drive is simulated in MATLAB/Simulink environment, and the obtained results are validated experimentally on a developed prototype of the drive.

  2. A PD Law Based Fuzzy Logic Control Strategy For Simultaneous Control Of Indoor Temperature And Humidity Using A Variable Speed Direct Expansion Air Conditioner

    Li, Zhao; Xu, Xiang Guo; Deng, Shi Ming; Pan, Dong Mei

    2014-01-01

    In small to medium scale buildings located in the subtropics, such as Hong Kong, direct expansion air conditioning (DX A/C) systems are widely applied. This is because, as compared to chilled water based central air conditioning systems, DX A/C systems are compact, flexible for multi-room services, energy efficient and cost less to maintain and operate. However, traditionally, a DX A/C system is equipped with a single-speed compressor and supply air fan, and employs ON / OFF control strategy ...

  3. Low speed phaselock speed control system. [for brushless dc motor

    Fulcher, R. W.; Sudey, J. (Inventor)

    1975-01-01

    A motor speed control system for an electronically commutated brushless dc motor is provided which includes a phaselock loop with bidirectional torque control for locking the frequency output of a high density encoder, responsive to actual speed conditions, to a reference frequency signal, corresponding to the desired speed. The system includes a phase comparator, which produces an output in accordance with the difference in phase between the reference and encoder frequency signals, and an integrator-digital-to-analog converter unit, which converts the comparator output into an analog error signal voltage. Compensation circuitry, including a biasing means, is provided to convert the analog error signal voltage to a bidirectional error signal voltage which is utilized by an absolute value amplifier, rotational decoder, power amplifier-commutators, and an arrangement of commutation circuitry.

  4. Performance evaluation of high speed compressors for high speed multipliers

    Nirlakalla Ravi

    2011-01-01

    Full Text Available This paper describes high speed compressors for high speed parallel multipliers like Booth Multiplier, Wallace Tree Multiplier in Digital Signal Processing (DSP. This paper presents 4-3, 5-3, 6-3 and 7-3 compressors for high speed multiplication. These compressors reduce vertical critical path more rapidly than conventional compressors. A 5-3 conventional compressor can take four steps to reduce bits from 5 to 3, but the proposed 5-3 takes only 2 steps. These compressors are simulated with H-Spice at a temperature of 25°C at a supply voltage 2.0V using 90nm MOSIS technology. The Power, Delay, Power Delay Product (PDP and Energy Delay Product (EDP of the compressors are calculated to analyze the total propagation delay and energy consumption. All the compressors are designed with half adder and full Adders only.

  5. Two cases of aerodynamic adjustment of sastrugi

    C. Amory

    2015-11-01

    Full Text Available In polar regions, sastrugi are a direct manifestation of wind driven snow and form the main surface roughness elements. In turn, sastrugi influence the local wind field and associated aeolian snow mass fluxes. Little attention has been paid to these feedback processes, mainly because of experimental difficulties, and, as a result most polar atmospheric models currently ignore sastrugi. More accurate quantification of the influence of sastrugi remains a major challenge. In the present study, wind profiles and aeolian snow mass fluxes were analyzed jointly on a sastrugi covered snowfield in Antarctica. Neutral stability 10 m air-snow drag coefficients CDN10 were computed from six level wind speed profiles collected in Adélie Land during austral winter 2013. The aeolian snow mass flux in the first meter above the surface of the snow was also measured using a windborne snow acoustic sensor. This paper focuses on two cases during which sastrugi responses to shifts in wind direction were evidenced by variations in snow mass flux and drag coefficients. Using this dataset, it was shown that (i the timescale of sastrugi aerodynamic adjustment can be as short as 3 h for friction velocities of 1 m s−1 or above and during strong windborne snow conditions, (ii CDN10 values were in the range of 1.3–1.5 × 103 when the wind was well aligned with the sastrugi and increased to 3 × 103 or higher when the wind only shifted 20–30°, (iii CDN10 can increase (to 120 % and the aeolian snow mass flux can decrease (to 80 % in response to a shift in wind direction, and (iv knowing CDN10 is not sufficient to estimate the erosion flux that results from drag partitioning at the surface because CDN10 includes the contribution of the sastrugi form drag. These results not only support the existence of feedback mechanisms linking sastrugi, aeolian particle transport and surface drag properties over snow surface but also provide orders of magnitude, although further

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

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

    2016-01-01

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

  7. Electric motors and drives. Pt. 27. AC motors. Pt. 1; Elektrische Maschinen und Antriebe. T. 27. Drehfeldmaschinen. T. 1

    Baral, Andreas [FHWT - Private Fachhochschule fuer Wirtschaft und Technik, Oldenburg (Germany). Elektrische Maschinen und Antriebstechnik

    2009-11-15

    AC motors like, for example, asynchronous and synchronous motors have an important role in propulsion technology. They are based on the principle of a rotary magnetic field resulting from the motor geometry and from a multiphase (usually three-phase) voltage system. The rotational frequency of the field and thus the rotary speed of the motors are directly dependent on the frequency of the feeding voltage system. (orig.)

  8. AC power generation from microbial fuel cells

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

    2015-11-01

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

  9. Performance of Halbach magnetized brushless AC motors

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

    2003-01-01

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

  10. Ac-dc converter firing error detection

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

  11. AC loss in superconducting tapes and cables

    Oomen, Marijn Pieter

    2000-01-01

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

  12. Precision Adjustable Liquid Regulator (ALR)

    Meinhold, R.; Parker, M.

    2004-10-01

    A passive mechanical regulator has been developed for the control of fuel or oxidizer flow to a 450N class bipropellant engine for use on commercial and interplanetary spacecraft. There are several potential benefits to the propulsion system, depending on mission requirements and spacecraft design. This system design enables more precise control of main engine mixture ratio and inlet pressure, and simplifies the pressurization system by transferring the function of main engine flow rate control from the pressurization/propellant tank assemblies, to a single component, the ALR. This design can also reduce the thermal control requirements on the propellant tanks, avoid costly Qualification testing of biprop engines for missions with more stringent requirements, and reduce the overall propulsion system mass and power usage. In order to realize these benefits, the ALR must meet stringent design requirements. The main advantage of this regulator over other units available in the market is that it can regulate about its nominal set point to within +/-0.85%, and change its regulation set point in flight +/-4% about that nominal point. The set point change is handled actively via a stepper motor driven actuator, which converts rotary into linear motion to affect the spring preload acting on the regulator. Once adjusted to a particular set point, the actuator remains in its final position unpowered, and the regulator passively maintains outlet pressure. The very precise outlet regulation pressure is possible due to new technology developed by Moog, Inc. which reduces typical regulator mechanical hysteresis to near zero. The ALR requirements specified an outlet pressure set point range from 225 to 255 psi, and equivalent water flow rates required were in the 0.17 lb/sec range. The regulation output pressure is maintained at +/-2 psi about the set point from a P (delta or differential pressure) of 20 to over 100 psid. Maximum upstream system pressure was specified at 320 psi

  13. Efficiency of particle swarm optimization applied on fuzzy logic DC motor speed control

    Allaoua Boumediene

    2008-01-01

    Full Text Available This paper presents the application of Fuzzy Logic for DC motor speed control using Particle Swarm Optimization (PSO. Firstly, the controller designed according to Fuzzy Logic rules is such that the systems are fundamentally robust. Secondly, the Fuzzy Logic controller (FLC used earlier was optimized with PSO so as to obtain optimal adjustment of the membership functions only. Finally, the FLC is completely optimized by Swarm Intelligence Algorithms. Digital simulation results demonstrate that in comparison with the FLC the designed FLC-PSO speed controller obtains better dynamic behavior and superior performance of the DC motor, as well as perfect speed tracking with no overshoot.

  14. Generalized Geometric Quantum Speed Limits

    Pires, Diego Paiva; Cianciaruso, Marco; Céleri, Lucas C.; Adesso, Gerardo; Soares-Pinto, Diogo O.

    2016-04-01

    The attempt to gain a theoretical understanding of the concept of time in quantum mechanics has triggered significant progress towards the search for faster and more efficient quantum technologies. One of such advances consists in the interpretation of the time-energy uncertainty relations as lower bounds for the minimal evolution time between two distinguishable states of a quantum system, also known as quantum speed limits. We investigate how the nonuniqueness of a bona fide measure of distinguishability defined on the quantum-state space affects the quantum speed limits and can be exploited in order to derive improved bounds. Specifically, we establish an infinite family of quantum speed limits valid for unitary and nonunitary evolutions, based on an elegant information geometric formalism. Our work unifies and generalizes existing results on quantum speed limits and provides instances of novel bounds that are tighter than any established one based on the conventional quantum Fisher information. We illustrate our findings with relevant examples, demonstrating the importance of choosing different information metrics for open system dynamics, as well as clarifying the roles of classical populations versus quantum coherences, in the determination and saturation of the speed limits. Our results can find applications in the optimization and control of quantum technologies such as quantum computation and metrology, and might provide new insights in fundamental investigations of quantum thermodynamics.

  15. Dazzle camouflage affects speed perception.

    Nicholas E Scott-Samuel

    Full Text Available Movement is the enemy of camouflage: most attempts at concealment are disrupted by motion of the target. Faced with this problem, navies in both World Wars in the twentieth century painted their warships with high contrast geometric patterns: so-called "dazzle camouflage". Rather than attempting to hide individual units, it was claimed that this patterning would disrupt the perception of their range, heading, size, shape and speed, and hence reduce losses from, in particular, torpedo attacks by submarines. Similar arguments had been advanced earlier for biological camouflage. Whilst there are good reasons to believe that most of these perceptual distortions may have occurred, there is no evidence for the last claim: changing perceived speed. Here we show that dazzle patterns can distort speed perception, and that this effect is greatest at high speeds. The effect should obtain in predators launching ballistic attacks against rapidly moving prey, or modern, low-tech battlefields where handheld weapons are fired from short ranges against moving vehicles. In the latter case, we demonstrate that in a typical situation involving an RPG7 attack on a Land Rover the reduction in perceived speed is sufficient to make the grenade miss where it was aimed by about a metre, which could be the difference between survival or not for the occupants of the vehicle.

  16. Ratios as a size adjustment in morphometrics.

    Albrecht, G H; Gelvin, B R; Hartman, S E

    1993-08-01

    Simple ratios in which a measurement variable is divided by a size variable are commonly used but known to be inadequate for eliminating size correlations from morphometric data. Deficiencies in the simple ratio can be alleviated by incorporating regression coefficients describing the bivariate relationship between the measurement and size variables. Recommendations have included: 1) subtracting the regression intercept to force the bivariate relationship through the origin (intercept-adjusted ratios); 2) exponentiating either the measurement or the size variable using an allometry coefficient to achieve linearity (allometrically adjusted ratios); or 3) both subtracting the intercept and exponentiating (fully adjusted ratios). These three strategies for deriving size-adjusted ratios imply different data models for describing the bivariate relationship between the measurement and size variables (i.e., the linear, simple allometric, and full allometric models, respectively). Algebraic rearrangement of the equation associated with each data model leads to a correctly formulated adjusted ratio whose expected value is constant (i.e., size correlation is eliminated). Alternatively, simple algebra can be used to derive an expected value function for assessing whether any proposed ratio formula is effective in eliminating size correlations. Some published ratio adjustments were incorrectly formulated as indicated by expected values that remain a function of size after ratio transformation. Regression coefficients incorporated into adjusted ratios must be estimated using least-squares regression of the measurement variable on the size variable. Use of parameters estimated by any other regression technique (e.g., major axis or reduced major axis) results in residual correlations between size and the adjusted measurement variable. Correctly formulated adjusted ratios, whose parameters are estimated by least-squares methods, do control for size correlations. The size-adjusted

  17. Brushless tachometer gives speed and direction

    Nola, F. J.

    1977-01-01

    Brushless electronic tachometer measures rotational speed and rotational direction, maintaining accuracy at high or low speeds. Unit is particularly useful in vacuum environments requiring low friction.

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

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

    1994-12-31

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

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

    Pawel Szczesniak

    2015-03-01

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

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

    Abbas, Qamar; Béguin, François

    2016-06-01

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

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

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

  2. Modified GIT model for predicting wind-speed behavior of low-grazing-angle radar sea clutter

    Zhang, Yu-Shi; Zhang, Jin-Peng; Li, Xin; Wu, Zhen-Sen

    2014-10-01

    A modified GIT model for describing the variational trend of mean clutter reflectivity as a function of wind speed is proposed. It uses two slope adjustment factors and two critical wind-speed factors to define and adjust the increasing slope of reflectivity with respect to wind speed. In addition, it uses a constant factor to compensate the overall amplitude of clutter reflectivity. The performance of the modified GIT model has been verified on the basis of the L-band low-grazing-angle radar sea clutter data. The results are in good agreement with the experimental data, indicating that the model is more effective in predicting the wind-speed behavior of clutter reflectivity than the conventional GIT model, especially for lower and higher wind speeds. We believe that the proposed model can provide deeper insights into the relationship between radar sea clutter reflectivity and sea state conditions.

  3. Modified GIT model for predicting wind-speed behavior of low-grazing-angle radar sea clutter

    A modified GIT model for describing the variational trend of mean clutter reflectivity as a function of wind speed is proposed. It uses two slope adjustment factors and two critical wind-speed factors to define and adjust the increasing slope of reflectivity with respect to wind speed. In addition, it uses a constant factor to compensate the overall amplitude of clutter reflectivity. The performance of the modified GIT model has been verified on the basis of the L-band low-grazing-angle radar sea clutter data. The results are in good agreement with the experimental data, indicating that the model is more effective in predicting the wind-speed behavior of clutter reflectivity than the conventional GIT model, especially for lower and higher wind speeds. We believe that the proposed model can provide deeper insights into the relationship between radar sea clutter reflectivity and sea state conditions. (interdisciplinary physics and related areas of science and technology)

  4. 75 FR 59684 - Trade Adjustment Assistance for Farmers

    2010-09-28

    ... Foreign Agricultural Service Trade Adjustment Assistance for Farmers AGENCY: Foreign Agricultural Service... analyzed by USDA's Economic Research Service and reviewed by the Trade Adjustment Assistance for Farmers... adjustment assistance in FY 2011. FOR FURTHER INFORMATION CONTACT: Trade Adjustment Assistance for...

  5. Application of Full-Order and Simplified EKFs to Sensorless PM Brushless AC Machines

    Xi Zhu; Zi-Qiang Zhu; David Howe

    2005-01-01

    This paper em ploys an extended Kalman filter (EKF) to estimate the rotor position and speed of a vector controlled surface-mounted permanent magnet (PM) brushless AC (BLAC) motor from measured terminal voltages and currents only. Both full-order and simplified EKFs are employed and their simulated performance capabilities are compared.Excellent agreement is achieved between estimated and commanded results. The EKF is also employed to identify the stator flux-linkage due to the PMs, which is influenced by temperature variation and magnetic saturation.

  6. A novel adjustable multiple cross-hexagonal search algorithm for fast block motion estimation

    2007-01-01

    In this paper, we propose a novel adjustable multiple cross-hexagonal search (AMCHS) algorithm for fast block motion estimation. It employs adjustable multiple cross search patterns (AMCSP) in the first step and then uses half-way-skip and half-way-stop technique to determine whether to employ two hexagonal search patterns (HSPs) subsequently. The AMCSP can be used to find small motion vectors efficiently while the HSPs can be used to find large ones accurately to ensure prediction quality.Simulation results showed that our proposed AMCHS achieves faster search speed, and provides better distortion performance than other popular fast search algorithms, such as CDS and CDHS.

  7. Adjustment of the Internal Tax Scale

    2013-01-01

    In application of Article R V 2.03 of the Staff Regulations, the internal tax scale has been adjusted with effect on 1 January 2012. The new scale may be consulted via the CERN Admin e-guide.  The notification of internal annual tax certificate for the financial year 2012 takes into account this adjustment. HR Department (Tel. 73907)

  8. Ergonomically Adjustable School Furniture for Male Students

    Al-Saleh, Khalid S.; Ramadan, Mohamed Z.; Al-Ashaikh, Riyad A.

    2013-01-01

    The need for adjustability in school furniture, in order to accommodate the variation in anthropometric measures of different genders, cultures and ages is becoming increasingly important. Four chair-table combinations, different in dimensions, with adjustable chair seating heights and table heights were designed, manufactured and distributed to…

  9. Adjustment Policies in the United States

    Blandford, David

    2003-01-01

    Principal adjustment programs are reviewed unemployment insurance (UI) and related long-term programs for displaced workers, and trade adjustment assistance (TAA). None of these programs has had wide application in agriculture, although the current trade act contains a new program specifically for farmers.

  10. 24 CFR 886.112 - Rent adjustments.

    2010-04-01

    ... Adjustment Factor most recently published by HUD in the Federal Register in accordance with 24 CFR part 888... unassisted housing in the area to ensure that adjustments in the Contract Rents shall not result in material differences between the rents charged for assisted and comparable unassisted units. Contract Rents may...

  11. A Digital Game for International Students' Adjustment

    Bisadi, Maryam; Chua, Alton Y. K; Keong, Lee Chu

    2013-01-01

    Although digital games have been developed for various subject areas, little attention has been focused on using digital games to address international students' adjustment issues. For this reason, this paper endeavors to explore the use of a digital game in facilitating international students acquire adjustment-related information. Specifically,…

  12. 10 CFR 905.34 - Adjustment provisions.

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Adjustment provisions. 905.34 Section 905.34 Energy DEPARTMENT OF ENERGY ENERGY PLANNING AND MANAGEMENT PROGRAM Power Marketing Initiative § 905.34 Adjustment... continue to take place based on existing contract/marketing criteria principles....

  13. Psychological Separation and Adjustment to College.

    Lapsley, Daniel K.; And Others

    1989-01-01

    Examined relationship between psychological separation and adjustment to college in freshmen (N=130) and upperclassmen (N=123). Found freshmen showed more psychological dependencies on parents than upperclassmen; separation appeared more strongly related to personal/emotional adjustment, particularly functional and emotional independence from…

  14. 34 CFR 36.2 - Penalty adjustment.

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Penalty adjustment. 36.2 Section 36.2 Education Office of the Secretary, Department of Education ADJUSTMENT OF CIVIL MONETARY PENALTIES FOR INFLATION § 36.2... applicable) penalty amount 20 U.S.C. 1015(c)(5) Provides for a fine of up to $25,000 for failure by...

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

    Sagar.S.Pawar; Prakash.T.Patil

    2015-01-01

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

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

    Sagar. S. Pawar

    2015-04-01

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

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

    Pawel Szczesniak

    2015-01-01

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

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

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

    2005-07-01

    This paper discusses the possible topologies and promising approaches towards direct single-phase AC-AC conversion of the mains voltage for audio applications. When compared to standard Class-D switching audio power amplifiers with a separate power supply, it is expected that direct conversion will provide better efficiency and higher level of integration, leading to lower component count, volume and cost, but at the expense of a minor performance deterioration. (au)

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

    S. Arumugam S. Ramareddy M. Sridhar

    2011-01-01

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

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

    Klumpner, Christian; Wijekoon, Thiwanka; Wheeler, Patrick

    2005-01-01

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

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

    Ljusev, Petar; Andersen, Michael Andreas E.

    2004-01-01

    This paper discusses the possible topologies and promising approaches towards direct single-phase AC-AC conversion of the mains voltage for audio applications. When compared to standard Class-D switching audio power amplifiers with a separate power supply, it is expected that direct conversion...... will provide better efficiency and higher level of integration, leading to lower component count, volume and cost, but at the expense of a minor performance deterioration....

  2. Attachment for sucker rod depth adjustment

    Collins, N.D.

    1992-04-07

    This patent describes a surface unit of an oil well pumping system, having a walking beam, a suspended carrier bar and an interconnected sucker rod assembly for stroking a reciprocating down-hole pump. It comprises a cross bar having a centrally located passage therein for the sucker rod assembly and adapted to be transversely supported by the carrier bar; a depth adjusting bar, having a centrally located passage therein for the sucker rod assembly, positioned at a selected fixed dimension above and parallel to the cross bar and adapted to operatively support the sucker rod assembly; clamping means for fixing the sucker rod relative to the depth adjusting bar; and hydraulically extendable means supportively connecting the depth adjusting bar to the cross bar on at least each side of the carrier bar for adjusting the selected fixed dimension and maintaining the adjustment during operation.

  3. Cultural Distance Asymmetry in Expatriate Adjustment

    Selmer, Jan; Chiu, Randy K.; Shenkar, Oded

    2007-01-01

    the assignment. Design/methodology/approach - Using a two-flow sample of US expatriates in Germany and German expatriates in the USA, we examine and compare the psychological and socio-cultural adjustment of each group of executives. Findings - Controlling for the length of assignment, we find that...... German expatriates in the USA were better adjusted, both socio-culturally and psychologically, than American expatriates in Germany. These results support the asymmetry hypothesis and call into question previous findings attesting to the relationship between CD and expatriate adjustment. Originality......Purpose - The current literature implicitly assumes a symmetric impact of cultural distance (CD) on expatriate adjustment. By using distance as a predictor of adjustment, the literature has rendered the direction of the flow irrelevant: a US expatriate in Germany is presumed to face the same hurdle...

  4. Vocational and social adjustment after laryngectomy.

    Goldberg, R T

    1975-01-01

    This study examined the vocational and social adjustment of 62 persons with cancer of the larynx. Predisability data were obtained by interview on 14 measures which assessed the vocational, social, and home adjustment prior to cancer. Post-disability data were obtained after laryngectomy by interview on 21 measures of adjustment. Additional measures include severity of laryngeal cancer classified by clinival stages, total or partial laryngectomy, presence of radiation therapy, presence of speech, months since surgery, age, sex, education, and marital status. The best predictors of vocational and social adjustment after laryngectomy were: removation, realism, rehabiltation outlook, previous vocational plans, highest educational grade, educational plans, and acquisition of speech. There were no significant differences in adjustment among patients in different clinical stages. PMID:1135615

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

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

  6. High-speed photonics interconnects

    Chrostowski, Lukas

    2013-01-01

    Dramatic increases in processing power have rapidly scaled on-chip aggregate bandwidths into the Tb/s range. This necessitates a corresponding increase in the amount of data communicated between chips, so as not to limit overall system performance. To meet the increasing demand for interchip communication bandwidth, researchers are investigating the use of high-speed optical interconnect architectures. Unlike their electrical counterparts, optical interconnects offer high bandwidth and negligible frequency-dependent loss, making possible per-channel data rates of more than 10 Gb/s. High-Speed

  7. Speeding chemical reactions by focusing

    Lacasta, A. M.; Ramírez-Piscina, L.; Sancho, J. M.; Lindenberg, K.

    2013-04-01

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, and obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate ˜t-1/2 to very close to the perfect mixing rate, ˜t-1.

  8. Speeding chemical reactions by focusing

    Lacasta, A M; Sancho, J M; Lindenberg, K

    2012-01-01

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate (t to the power -1/2) to very close to the perfect mixing rate, (t to the power -1).

  9. Motor Integrated Variable Speed Drives

    Singh, Yash Veer

    A new trend in the variable speed drives (VSDs) is to develop fully integrated systems, which lead to low-cost products with shorter design cycles. Motor Integrated design of VSDs will reduce cable length to connect drive with machine windings and installation time for end user. The electric drives...... converter losses and its size so it can fit inside the motor housing. Weight and volume of a filter inductor has to come down drastically to make it a suitable power converter for motor integrated variable speed drives. Introduction of active power electronic switches can ensure very high performance and...

  10. Instant PageSpeed optimization

    Jaiswal, Sanjeev

    2013-01-01

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. Instant PageSpeed Optimization is a hands-on guide that provides a number of clear, step-by-step exercises for optimizing your websites for better performance and improving their efficiency.Instant PageSpeed Optimization is aimed at website developers and administrators who wish to make their websites load faster without any errors and consume less bandwidth. It's assumed that you will have some experience in basic web technologies like HTML, CSS3, JavaScript, and the basics of netw

  11. High-speed pulse techniques

    Coekin, J A

    1975-01-01

    High-Speed Pulse Techniques covers the many aspects of technique in digital electronics and encompass some of the more fundamental factors that apply to all digital systems. The book describes the nature of pulse signals and their deliberate or inadvertent processing in networks, transmission lines and transformers, and then examines the characteristics and transient performance of semiconductor devices and integrated circuits. Some of the problems associated with the assembly of these into viable systems operating at ultra high speed are also looked at. The book examines the transients and w

  12. Joint Modeling of Ability and Differential Speed Using Responses and Response Times.

    Fox, Jean-Paul; Marianti, Sukaesi

    2016-01-01

    With computerized testing, it is possible to record both the responses of test takers to test questions (i.e., items) and the amount of time spent by a test taker in responding to each question. Various models have been proposed that take into account both test-taker ability and working speed, with the many models assuming a constant working speed throughout the test. The constant working speed assumption may be inappropriate for various reasons. For example, a test taker may need to adjust the pace due to time mismanagement, or a test taker who started out working too fast may reduce the working speed to improve accuracy. A model is proposed here that allows for variable working speed. An illustration of the model using the Amsterdam Chess Test data is provided. PMID:27269482

  13. Rotor speed estimation for indirect stator flux oriented induction motor drive based on MRAS scheme

    Youssef Agrebi

    2007-09-01

    Full Text Available In this paper, a conventional indirect stator flux oriented controlled (ISFOC induction motor drive is presented. In order to eliminate the speed sensor, an adaptation algorithm for tuning the rotor speed is proposed. Based on the model reference adaptive system (MRAS scheme, the rotor speed is tuned to obtain an exact ISFOC induction motor drive. The reference and adjustable models, developed in stationary stator reference frame, are used in the MRAS scheme to estimate induction rotor peed from measured terminal voltages and currents. The IP gains speed controller and PI gains current controller are calculated and tuned at each sampling time according to the new estimated rotor speed. The proposed algorithm has been tested by numerical simulation, showing the capability of driving active load; and stability is preserved. Experimental results obtained with a general-purpose 1-kW induction machine are presented showing the effectiveness of the proposed approach in terms of dynamic performance.

  14. Processing speed differences between 70- and 83-year-olds matched on childhood IQ☆

    Deary, Ian J.; Ritchie, Stuart J.

    2016-01-01

    Processing speed is an important human cognitive capability that might underlie differences in other cognitive skills and their aging. We aimed to test aging-related processing speed differences using a novel cross-sectional design that adjusted for cognitive ability tested in youth. We examined aging differences on three different ways of assessing processing speed: psychometric, experimental, and psychophysical. We compared large narrow-age cohorts of 70- and 83-year-old people who were matched for cognitive ability in childhood. There were decrements of substantial effect size in all processing speed assessments in the older group that were not accounted for by prior cognitive ability, health, or fitness differences, though these factors also contributed to processing speed differences. These findings confirm age-related cognitive slowing using an unusual research design, and provide evidence against recent theories characterizing aging-related cognitive decline as a myth. PMID:27019542

  15. Second messenger-mediated adjustment of bacterial swimming velocity.

    Boehm, Alex; Kaiser, Matthias; Li, Hui; Spangler, Christian; Kasper, Christoph Alexander; Ackermann, Martin; Kaever, Volkhard; Sourjik, Victor; Roth, Volker; Jenal, Urs

    2010-04-01

    Bacteria swim by means of rotating flagella that are powered by ion influx through membrane-spanning motor complexes. Escherichia coli and related species harness a chemosensory and signal transduction machinery that governs the direction of flagellar rotation and allows them to navigate in chemical gradients. Here, we show that Escherichia coli can also fine-tune its swimming speed with the help of a molecular brake (YcgR) that, upon binding of the nucleotide second messenger cyclic di-GMP, interacts with the motor protein MotA to curb flagellar motor output. Swimming velocity is controlled by the synergistic action of at least five signaling proteins that adjust the cellular concentration of cyclic di-GMP. Activation of this network and the resulting deceleration coincide with nutrient depletion and might represent an adaptation to starvation. These experiments demonstrate that bacteria can modulate flagellar motor output and thus swimming velocity in response to environmental cues. PMID:20303158

  16. 21 CFR 880.5500 - AC-powered patient lift.

    2010-04-01

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

  17. An 82 MW variable speed pumped-storage system

    Tanaka, H. (Toshiba Corp., Tokyo (Japan). Principal Office)

    1991-11-01

    An existing reversible pumped-storage unit, Unit 2 of the Yagisawa power station in Japan, has recently been converted to a variable speed reversible unit, using a large-scale cycloconverter system. It was put into operation successfully in December 1990. The variable speed operation of the reversible unit has many advantageous electrical and hydraulic features, as follows. Electrical: improvement in the ability to adjust the power system frequency even in the pumping mode (at off-peak times); improvement in power system stability; quick response of active power by using the flywheel effect; quick response of reactive power compensation; and, elimination of pump starting system. Hydraulic: variable power and discharge in the pumping mode; improvement in hydraulic efficiency in the generating mode; broader part load operation range in the generating mode; and, broader operable head range in the generating mode. (author).

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

    满瑞; 李秋俊

    2012-01-01

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

  19. An Inexpensive and Versatile Version of Kundt's Tube for Measuring the Speed of Sound in Air

    Papacosta, Pangratios; Linscheid, Nathan

    2016-01-01

    Experiments that measure the speed of sound in air are common in high schools and colleges. In the Kundt's tube experiment, a horizontal air column is adjusted until a resonance mode is achieved for a specific frequency of sound. When this happens, the cork dust in the tube is disturbed at the displacement antinode regions. The location of the…

  20. Cross-Cultural Adjustment of Chinese Students in Japan: School Adjustment and Educational Support

    Li, Yuan Xiang; Sano, Hideki; Ahn, Ruth

    2013-01-01

    This study investigates Chinese immigrant students' cross-cultural and school adjustment issues in Japanese schools. Using a quantitative method, a survey which collected students' demographic information, cross-cultural adjustment, and school adjustment questions was administered to 143 Chinese junior high and high school students in…