WorldWideScience

Sample records for minimum power speed

  1. Winding Design for Minimum Power Loss and Low-Cost Manufacture in Application to Fixed-Speed PM Generator

    OpenAIRE

    Wrobel, Rafal; Staton, David; Lock, Richard J; Booker, Julian D; Drury, David

    2015-01-01

    This paper presents the results from a coupled thermal and power loss analysis of an open-slot permanent-magnet (PM) generator. The research focus has been placed on the winding design providing minimum power loss at an ac operation, together with low-cost manufacture. The analyzed PM generator is intended to operate at a fixed speed, allowing for the winding design to be finely tuned for a single operating point. Such a design approach has not been widely reported in literature, and the exis...

  2. The Factors that Determine the Minimum Speed of an Airplane

    Science.gov (United States)

    Norton, F H

    1921-01-01

    The author argues that because of a general misunderstanding of the principles of flight at low speed, there are a large number of airplanes that could be made to fly several miles per hour slower than at present by making slight modifications. In order to show how greatly the wing section affects the minimum speed, curves are plotted against various loadings. The disposition of wings on the airplane slightly affects the lift coefficient, and a few such cases are discussed. Another factor that has an effect on minimum speed is the extra lift exerted by the slip stream on the wings. Also discussed are procedures to be followed by the pilot, especially with regard to stick movements during low speed flight. Also covered are stalling, yaw, rolling moments, lateral control, and the effectiveness of ailerons and rudders.

  3. Minimum Plate Thickness in High-Speed Craft

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Zhang, Shengming

    1998-01-01

    The minimum plate thickness requirements specified by the classification societies for high-speed craft are supposed to ensure adequate resistance to impact loads such as collision with floating objects and objects falling on the deck. The paper presents analytical methods of describing such impact...... phenomena and proposes performance requirements instead of thickness requirements for hull panels in high-speed craft made of different building materials....

  4. Deformed special relativity with an invariant minimum speed and its ...

    Indian Academy of Sciences (India)

    On the other hand, according to special relativity (SR), the momentum cannot ... Deformed special relativity with an invariant minimum speed ..... However, we need to show that there is an anti-gravitational interaction between the ordinary proof mass m and the big sphere with a 'dark mass' of vacuum (MΛ), but let us first ...

  5. Minimum resolvable power contrast model

    Science.gov (United States)

    Qian, Shuai; Wang, Xia; Zhou, Jingjing

    2018-01-01

    Signal-to-noise ratio and MTF are important indexs to evaluate the performance of optical systems. However,whether they are used alone or joint assessment cannot intuitively describe the overall performance of the system. Therefore, an index is proposed to reflect the comprehensive system performance-Minimum Resolvable Radiation Performance Contrast (MRP) model. MRP is an evaluation model without human eyes. It starts from the radiance of the target and the background, transforms the target and background into the equivalent strips,and considers attenuation of the atmosphere, the optical imaging system, and the detector. Combining with the signal-to-noise ratio and the MTF, the Minimum Resolvable Radiation Performance Contrast is obtained. Finally the detection probability model of MRP is given.

  6. Power production at minimum risk

    International Nuclear Information System (INIS)

    Fremlin, J.H.

    1983-01-01

    A summary, including extensive quotations, is given of the main themes of a lecture by Prof. Fremlin in which he assessed the risks inherent in the use of various power systems. Considering only hazards which affect members of the public, the methods used to quantify such risks are examined. Both so-called inconspicuous hazards from radiation effects and conspicuous risks from accidents which could arise from nuclear power stations are compared to those from other types of power generation. The small risk arising from nuclear wastes is stressed. The lecturer concluded that he would not let 'tiny differences of risk' affect his decisions on energy planning. (U.K.)

  7. Normalized Minimum Error Entropy Algorithm with Recursive Power Estimation

    Directory of Open Access Journals (Sweden)

    Namyong Kim

    2016-06-01

    Full Text Available The minimum error entropy (MEE algorithm is known to be superior in signal processing applications under impulsive noise. In this paper, based on the analysis of behavior of the optimum weight and the properties of robustness against impulsive noise, a normalized version of the MEE algorithm is proposed. The step size of the MEE algorithm is normalized with the power of input entropy that is estimated recursively for reducing its computational complexity. The proposed algorithm yields lower minimum MSE (mean squared error and faster convergence speed simultaneously than the original MEE algorithm does in the equalization simulation. On the condition of the same convergence speed, its performance enhancement in steady state MSE is above 3 dB.

  8. Minimum critical power ratio control device for nuclear power plants

    International Nuclear Information System (INIS)

    Kurosawa, Tsuneo.

    1991-01-01

    Reactor core flowrate is determined by comparing a minimum critical power ratio calculated based on the status amount of a nuclear power plant and a control value for the minimum critical power ratio that depends on the reactor core flowrate. Further, the minimum critical power ratio and a control value for the minimum critical power ratio that depends on the reactor thermal power are compared to set a reactor thermal power converted to a reactor core flowrate. Deviation between the thus determined reactor core flowrate and the present reactor core flowrate is calculated. When the obtained deviation is lower than a rated value, a reactor core flowrate set signal is generated to a reactor flowrate control means, to control the reactor power by a recycling flowrate control system of the reactor. On the other hand, when the deviation exceeds the determined value, the reactor core flowrate set signal is converted into a reactor thermal power, to control the position of control rods and control the reactor power. Then, monitor and control can be conducted safely and automatically without depending on operator's individual ability over the entire operation range corresponding to load following operation. (N.H.)

  9. Supplementary speed control for wind power smoothing

    NARCIS (Netherlands)

    Haan, de J.E.S.; Frunt, J.; Kechroud, A.; Kling, W.L.

    2010-01-01

    Wind fluctuations result in even larger wind power fluctuations because the power of wind is proportional to the cube of the wind speed. This report analyzes wind power fluctuations to investigate inertial power smoothing, in particular for the frequency range of 0.08 - 0.5 Hz. Due to the growing

  10. Deformed special relativity with an energy barrier of a minimum speed

    International Nuclear Information System (INIS)

    Nassif, Claudio

    2011-01-01

    Full text: This research aims to introduce a new principle of symmetry in the flat space-time by means of the elimination of the classical idea of rest, and by including a universal minimum limit of speed in the quantum world. Such a limit, unattainable by the particles, represents a preferred inertial reference frame associated with a universal background field that breaks Lorentz symmetry. So there emerges a new relativistic dynamics where a minimum speed forms an inferior energy barrier. One of the interesting implications of the existence of such a minimum speed is that it prevents the absolute zero temperature for an ultracold gas, according to the third law of thermodynamics. So we will be able to provide a fundamental dynamical explanation for the third law by means of a connection between such a phenomenological law and the new relativistic dynamics with a minimum speed. In other words we say that our relevant investigation is with respect to the problem of the absolute zero temperature in the thermodynamics of an ideal gas. We have made a connection between the 3 rd law of Thermodynamics and the new dynamics with a minimum speed by means of a relation between the absolute zero temperature (T = 0 deg K) and a minimum average speed (V) for a gas with N particles (molecules or atoms). Since T = 0 deg K is thermodynamically unattainable, we have shown this is due to the impossibility of reaching V from the new dynamics standpoint. (author)

  11. 14 CFR 25.149 - Minimum control speed.

    Science.gov (United States)

    2010-01-01

    ... used to simulate critical engine failure must represent the most critical mode of powerplant failure with respect to controllability expected in service. (b) VMC is the calibrated airspeed at which, when... be necessary to reduce power or thrust of the operative engines. During recovery, the airplane may...

  12. Power, speed & automation with Adobe Photoshop

    CERN Document Server

    Scott, Geoff

    2012-01-01

    This is a must for the serious Photoshop user! Power, Speed & Automation explores how to customize and automate Photoshop to increase your speed and productivity.  With numerous step-by-step instructions, the authors-two of Adobe's own software developers!- walk you through the steps to best tailor Photoshop's interface to your personal workflow; write and apply Actions; and use batching and scripts to process large numbers of images quickly and automatically.  You will learn how to build your own dialogs and panels to improve your production workflows in Photoshop, the secrets of changing

  13. Minimum load reduction for once-through boiler power plants

    International Nuclear Information System (INIS)

    Colombo, P.; Godina, G.; Manganelli, R.

    2001-01-01

    In Italy the liberalization process of energy market is giving particular importance to the optimization of power plants performances; especially for those that will be called to satisfy grid peak demands. On those plants some techniques have been experimented for the reduction of minimum load; these techniques, investigated and tested by an engineering dynamic simulator, have been sequentially tested on plant. The minimum load for up 320 MW of Tavazzano power plants has been diminished from 140 down to 80 MW without plant modification [it

  14. Analysis of wind speed distributions: Wind distribution function derived from minimum cross entropy principles as better alternative to Weibull function

    International Nuclear Information System (INIS)

    Kantar, Yeliz Mert; Usta, Ilhan

    2008-01-01

    In this study, the minimum cross entropy (MinxEnt) principle is applied for the first time to the wind energy field. This principle allows the inclusion of previous information of a wind speed distribution and covers the maximum entropy (MaxEnt) principle, which is also discussed by Li and Li and Ramirez as special cases in their wind power study. The MinxEnt probability density function (pdf) derived from the MinxEnt principle are used to determine the diurnal, monthly, seasonal and annual wind speed distributions. A comparison between MinxEnt pdfs defined on the basis of the MinxEnt principle and the Weibull pdf on wind speed data, which are taken from different sources and measured in various regions, is conducted. The wind power densities of the considered regions obtained from Weibull and MinxEnt pdfs are also compared. The results indicate that the pdfs derived from the MinxEnt principle fit better to a variety of measured wind speed data than the conventionally applied empirical Weibull pdf. Therefore, it is shown that the MinxEnt principle can be used as an alternative method to estimate both wind distribution and wind power accurately

  15. SPEED POWER AFTER DIFFERENT TRAINING METHODS

    Directory of Open Access Journals (Sweden)

    Milan Gužvica

    2011-09-01

    Full Text Available As the strength is a very important capability, with which are more or less, related and all other motor skills relevant to the successful conduct of sports fight in karate, we were interested in what extent the ability of the speed of force development changes under the influence of different types of loads. For this purpose we used two different methods: the development of speed power with weights and plyometric method. Research is organized on a sample of 20 subjects (first year students of the College of Internal Affairs in Banja Luka, divided into two groups, of which only 12 students responded to the demands of research. The program was implemented during the period of six weeks for two hours per week. Before beginning and three days after the training process, we also tested levels of speed power using eight specific motor tests. After completion of the initial and final measurements, data were analyzed by appropriate statistical procedures, where all respondents, across the various tests, achieved better results. However, statistically significant differences were not obtained in both groups. Specifically, statistically significant differences were obtained in the group T across the various tests, while in group P, statistically significant differences were not obtained in three tests conducted. Given results allowed us that, with caution, we conclude that the method of working with weights, in a limited period of time, when it comes to beginners, is still more efficient than the plyometric method of work. Therefore recommendation for increasing the speed power, in a limited period of time, is to use a method of working with weights.

  16. Adjustable Speed Drives and Power Quality

    DEFF Research Database (Denmark)

    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...... frontend rectifiers even at partial loading conditions. Moreover, the effectiveness of the EI technique along with a phase-shifted current control in terms of improved grid current quality in multi-drive configurations is addressed. Furthermore, a novel DC-link current modulation scheme for multi...

  17. Low speed turbines for nuclear power plants

    International Nuclear Information System (INIS)

    Ugol'nikov, V.V.; Kosyak, Yu.F.; Virchenko, M.A.

    1975-01-01

    Work of the Kharkov turbine plant on planning and manufacture for nuclear power plants of low-speed (1500 rpm) turbines with a power of 500-1000 MW is described. The selection of a construction diagram for the turbine assembly, determined basically by the presence or absence of parts of average pressure, is considered. Special construction features of the condenser and turbine are described. Turbine K-500, with a rate of 1500 rpm, was calculated for operation in a two-loop nuclear power plant with saturated steam with intermediate separation and two-stage steam regeneration. On the base of this turbine, three models of 1000-MW turbines were developed. The first model has a cylinder of average pressure (TsSD) and a lateral condenser. The second has no TsSD but a low location of the condensers. The third has no TsSD and the condensers are located laterally. Calculations of the heat efficiency of the three types of turbines showed that several advantages are offered by the model with a TsSD. Better aerodynamic properties of the exhaust nozzles and condensers with lateral location allows decreasing the specific heat consumption to 0.5-1% or, at the same power, a 10-20% decrease in cooling water consumption

  18. Output Power Control of Wind Turbine Generator by Pitch Angle Control using Minimum Variance Control

    Science.gov (United States)

    Senjyu, Tomonobu; Sakamoto, Ryosei; Urasaki, Naomitsu; Higa, Hiroki; Uezato, Katsumi; Funabashi, Toshihisa

    In recent years, there have been problems such as exhaustion of fossil fuels, e. g., coal and oil, and environmental pollution resulting from consumption. Effective utilization of renewable energies such as wind energy is expected instead of the fossil fuel. Wind energy is not constant and windmill output is proportional to the cube of wind speed, which cause the generated power of wind turbine generators (WTGs) to fluctuate. In order to reduce fluctuating components, there is a method to control pitch angle of blades of the windmill. In this paper, output power leveling of wind turbine generator by pitch angle control using an adaptive control is proposed. A self-tuning regulator is used in adaptive control. The control input is determined by the minimum variance control. It is possible to compensate control input to alleviate generating power fluctuation with using proposed controller. The simulation results with using actual detailed model for wind power system show effectiveness of the proposed controller.

  19. Finding Minimum-Power Broadcast Trees for Wireless Networks

    Science.gov (United States)

    Arabshahi, Payman; Gray, Andrew; Das, Arindam; El-Sharkawi, Mohamed; Marks, Robert, II

    2004-01-01

    Some algorithms have been devised for use in a method of constructing tree graphs that represent connections among the nodes of a wireless communication network. These algorithms provide for determining the viability of any given candidate connection tree and for generating an initial set of viable trees that can be used in any of a variety of search algorithms (e.g., a genetic algorithm) to find a tree that enables the network to broadcast from a source node to all other nodes while consuming the minimum amount of total power. The method yields solutions better than those of a prior algorithm known as the broadcast incremental power algorithm, albeit at a slightly greater computational cost.

  20. A minimum attention control center for nuclear power plants

    International Nuclear Information System (INIS)

    Meijer, C.H.

    1986-01-01

    Control Centers for Nuclear Power Plants have characteristically been designed for maximum attention by the operating staffs of these plants. Consequently, the monitoring, control and diagnostics oriented cognitive activities by these staffs, were mostly ''data-driven'' in nature. This paper addresses a control center concept, under development by Combustion Engineering, that promotes a more ''information-driven'' cognitive interaction process between the operator and the plant. The more ''intelligent'' and therefore less attentive nature of such interactive process utilizes computer implemented cognitive engineered algorithms. The underlying structure of these algorithms is based upon the Critical Function/Success Path monitoring principle. The paper highlights a typical implementation of the minimum attention concept for the handling of unfamiliar safety related events. (author)

  1. An Analysis of Variable-Speed Wind Turbine Power-Control Methods with Fluctuating Wind Speed

    Directory of Open Access Journals (Sweden)

    Seung-Il Moon

    2013-07-01

    Full Text Available Variable-speed wind turbines (VSWTs typically use a maximum power-point tracking (MPPT method to optimize wind-energy acquisition. MPPT can be implemented by regulating the rotor speed or by adjusting the active power. The former, termed speed-control mode (SCM, employs a speed controller to regulate the rotor, while the latter, termed power-control mode (PCM, uses an active power controller to optimize the power. They are fundamentally equivalent; however, since they use a different controller at the outer control loop of the machine-side converter (MSC controller, the time dependence of the control system differs depending on whether SCM or PCM is used. We have compared and analyzed the power quality and the power coefficient when these two different control modes were used in fluctuating wind speeds through computer simulations. The contrast between the two methods was larger when the wind-speed fluctuations were greater. Furthermore, we found that SCM was preferable to PCM in terms of the power coefficient, but PCM was superior in terms of power quality and system stability.

  2. Speed of sound in biodiesel produced by low power ultrasound

    Science.gov (United States)

    Oliveira, P. A.; Silva, R. M. B.; Morais, G. C.; Alvarenga, A. V.; Costa-Felix, R. P. B.

    2018-03-01

    The quality control of the biodiesel produced is an important issue to be addressed for every manufacturer or retailer. The speed of sound is a property that has an influence on the quality of the produced fuel. This work presents the evaluation about the speed of sound in biodiesel produced with the aid of low power ultrasound in the frequencies of 1 MHz and 3 MHz. The speed of sound was measured by pulse-echo technique. The ultrasonic frequency used during reaction affects the speed of sound in biodiesel. The larger expanded uncertainty for adjusted curve was 4.9 m.s-1.

  3. Dual power, constant speed electric motor system

    Science.gov (United States)

    Kirschbaum, H.S.

    1984-07-31

    A dual capacity permanent split capacitor electric motor system is provided with a stator having main and auxiliary windings. The main stator winding includes two winding sections which are connected in parallel with each other and across a pair of line terminals while the auxiliary winding is connected in series with a capacitor to form a circuit branch which is connected between the line terminals for operation at a first output power level. Switching means are provided to reconnect the main stator winding sections in series with each other and in series with a second capacitor to form a circuit branch which is connected between the line terminals while the stator auxiliary winding is connected directly between the line terminals for operation at a second output power level. Automatic rotation reversal occurs when the motor switches from the first to the second output power level. 6 figs.

  4. Dual power, constant speed electric motor system

    Science.gov (United States)

    Kirschbaum, Herbert S.

    1984-01-01

    A dual capacity permanent split capacitor electric motor system is provided with a stator having main and auxiliary windings. The main stator winding includes two winding sections which are connected in parallel with each other and across a pair of line terminals while the auxiliary winding is connected in series with a capacitor to form a circuit branch which is connected between the line terminals for operation at a first output power level. Switching means are provided to reconnect the main stator winding sections in series with each other and in series with a second capacitor to form a circuit branch which is connected between the line terminals while the stator auxiliary winding is connected directly between the line terminals for operation at a second output power level. Automatic rotation reversal occurs when the motor switches from the first to the second output power level.

  5. Tip Speed Ratio Based Maximum Power Tracking Control of Variable Speed Wind Turbines; A Comprehensive Design

    Directory of Open Access Journals (Sweden)

    Murat Karabacak

    2017-08-01

    Full Text Available The most primitive control method of wind turbines used to generate electric energy from wind is the fixed speed control method. With this method, it is not possible that turbine input power is transferred to grid at maximum rate. For this reason, Maximum Power Tracking (MPT schemes are proposed. In order to implement MPT, the propeller has to rotate at a different speed for every different wind speed. This situation has led MPT based systems to be called Variable Speed Wind Turbine (VSWT systems. In VSWT systems, turbine input power can be transferred to grid at rates close to maximum power. When MPT based control of VSWT systems is the case, two important processes come into prominence. These are instantaneously determination and tracking of MPT point. In this study, using a Maximum Power Point Tracking (MPPT method based on tip speed ratio, power available in wind is transferred into grid over a back to back converter at maximum rate via a VSWT system with permanent magnet synchronous generator (PMSG. Besides a physical wind turbine simulator is modelled and simulated. Results show that a time varying MPPT point is tracked with a high performance.

  6. Improving transition between power optimization and power limitation of variable speed/variable pitch wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A D; Bindner, H [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark); Rebsdorf, A [Vestas Wind Systems A/S, Lem (Denmark)

    1999-03-01

    The paper summarises and describes the main results of a recently performed study of improving the transition between power optimization and power limitation for variable speed/variable pitch wind turbines. The results show that the capability of varying the generator speed also can be exploited in the transition stage to improve the quality of the generated power. (au)

  7. Effects of vehicle power on passenger vehicle speeds.

    Science.gov (United States)

    McCartt, Anne T; Hu, Wen

    2017-07-04

    During the past 2 decades, there have been large increases in mean horsepower and the mean horsepower-to-vehicle weight ratio for all types of new passenger vehicles in the United States. This study examined the relationship between travel speeds and vehicle power, defined as horsepower per 100 pounds of vehicle weight. Speed cameras measured travel speeds and photographed license plates and drivers of passenger vehicles traveling on roadways in Northern Virginia during daytime off-peak hours in spring 2013. The driver licensing agencies in the District of Columbia, Maryland, and Virginia provided vehicle information numbers (VINs) by matching license plate numbers with vehicle registration records and provided the age, gender, and ZIP code of the registered owner(s). VINs were decoded to obtain the curb weight and horsepower of vehicles. The study focused on 26,659 observed vehicles for which information on horsepower was available and the observed age and gender of drivers matched vehicle registration records. Log-linear regression estimated the effects of vehicle power on mean travel speeds, and logistic regression estimated the effects of vehicle power on the likelihood of a vehicle traveling over the speed limit and more than 10 mph over the limit. After controlling for driver characteristics, speed limit, vehicle type, and traffic volume, a 1-unit increase in vehicle power was associated with a 0.7% increase in mean speed, a 2.7% increase in the likelihood of a vehicle exceeding the speed limit by any amount, and an 11.6% increase in the likelihood of a vehicle exceeding the limit by 10 mph. All of these increases were highly significant. Speeding persists as a major factor in crashes in the United States. There are indications that travel speeds have increased in recent years. The current findings suggest the trend toward substantially more powerful vehicles may be contributing to higher speeds. Given the strong association between travel speed and crash

  8. Predicting Minimum Control Speed on the Ground (VMCG) and Minimum Control Airspeed (VMCA) of Engine Inoperative Flight Using Aerodynamic Database and Propulsion Database Generators

    Science.gov (United States)

    Hadder, Eric Michael

    There are many computer aided engineering tools and software used by aerospace engineers to design and predict specific parameters of an airplane. These tools help a design engineer predict and calculate such parameters such as lift, drag, pitching moment, takeoff range, maximum takeoff weight, maximum flight range and much more. However, there are very limited ways to predict and calculate the minimum control speeds of an airplane in engine inoperative flight. There are simple solutions, as well as complicated solutions, yet there is neither standard technique nor consistency throughout the aerospace industry. To further complicate this subject, airplane designers have the option of using an Automatic Thrust Control System (ATCS), which directly alters the minimum control speeds of an airplane. This work addresses this issue with a tool used to predict and calculate the Minimum Control Speed on the Ground (VMCG) as well as the Minimum Control Airspeed (VMCA) of any existing or design-stage airplane. With simple line art of an airplane, a program called VORLAX is used to generate an aerodynamic database used to calculate the stability derivatives of an airplane. Using another program called Numerical Propulsion System Simulation (NPSS), a propulsion database is generated to use with the aerodynamic database to calculate both VMCG and VMCA. This tool was tested using two airplanes, the Airbus A320 and the Lockheed Martin C130J-30 Super Hercules. The A320 does not use an Automatic Thrust Control System (ATCS), whereas the C130J-30 does use an ATCS. The tool was able to properly calculate and match known values of VMCG and VMCA for both of the airplanes. The fact that this tool was able to calculate the known values of VMCG and VMCA for both airplanes means that this tool would be able to predict the VMCG and VMCA of an airplane in the preliminary stages of design. This would allow design engineers the ability to use an Automatic Thrust Control System (ATCS) as part

  9. The speed-curvature power law of movements: a reappraisal.

    Science.gov (United States)

    Zago, Myrka; Matic, Adam; Flash, Tamar; Gomez-Marin, Alex; Lacquaniti, Francesco

    2018-01-01

    Several types of curvilinear movements obey approximately the so called 2/3 power law, according to which the angular speed varies proportionally to the 2/3 power of the curvature. The origin of the law is debated but it is generally thought to depend on physiological mechanisms. However, a recent paper (Marken and Shaffer, Exp Brain Res 88:685-690, 2017) claims that this power law is simply a statistical artifact, being a mathematical consequence of the way speed and curvature are calculated. Here we reject this hypothesis by showing that the speed-curvature power law of biological movements is non-trivial. First, we confirm that the power exponent varies with the shape of human drawing movements and with environmental factors. Second, we report experimental data from Drosophila larvae demonstrating that the power law does not depend on how curvature is calculated. Third, we prove that the law can be violated by means of several mathematical and physical examples. Finally, we discuss biological constraints that may underlie speed-curvature power laws discovered in empirical studies.

  10. Trend on High-speed Power Line Communication Technology

    Science.gov (United States)

    Ogawa, Osamu

    High-speed power line communication (PLC) is useful technology to easily build the communication networks, because construction of new infrastructure is not necessary. In Europe and America, PLC has been used for broadband networks since the beginning of 21th century. In Japan, high-speed PLC was deregulated only indoor usage in 2006. Afterward it has been widely used for home area network, LAN in hotels and school buildings and so on. And recently, PLC is greatly concerned as communication technology for smart grid network. In this paper, the author surveys the high-speed PLC technology and its current status.

  11. Overview of Variable-Speed Power-Turbine Research

    Science.gov (United States)

    Welch, Gerard E.

    2011-01-01

    The vertical take-off and landing (VTOL) and high-speed cruise capability of the NASA Large Civil Tilt-Rotor (LCTR) notional vehicle is envisaged to enable increased throughput in the national airspace. A key challenge of the LCTR is the requirement to vary the main rotor speeds from 100% at take-off to near 50% at cruise as required to minimize mission fuel burn. The variable-speed power-turbine (VSPT), driving a fixed gear-ratio transmission, provides one approach for effecting this wide speed variation. The key aerodynamic and rotordynamic challenges of the VSPT were described in the FAP Conference presentation. The challenges include maintaining high turbine efficiency at high work factor, wide (60 deg.) of incidence variation in all blade rows due to the speed variation, and operation at low Reynolds numbers (with transitional flow). The PT -shaft of the VSPT must be designed for safe operation in the wide speed range required, and therefore poses challenges associated with rotordynamics. The technical challenges drive research activities underway at NASA. An overview of the NASA SRW VSPT research activities was provided. These activities included conceptual and preliminary aero and mechanical (rotordynamics) design of the VSPT for the LCTR application, experimental and computational research supporting the development of incidence tolerant blading, and steps toward component-level testing of a variable-speed power-turbine of relevance to the LCTR application.

  12. The power of reordering for online minimum makespan scheduling

    OpenAIRE

    Englert, Matthias; Özmen, Deniz; Westermann, Matthias

    2014-01-01

    In the classic minimum makespan scheduling problem, we are given an input sequence of jobs with processing times. A scheduling algorithm has to assign the jobs to m parallel machines. The objective is to minimize the makespan, which is the time it takes until all jobs are processed. In this paper, we consider online scheduling algorithms without preemption. However, we do not require that each arriving job has to be assigned immediately to one of the machines. A reordering buffer with limited...

  13. Wind speed power spectrum analysis for Bushland, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Eggleston, E.D. [USDA-Agricultural Research Service, Bushland, TX (United States)

    1996-12-31

    Numerous papers and publications on wind turbulence have referenced the wind speed spectrum presented by Isaac Van der Hoven in his article entitled Power Spectrum of Horizontal Wind Speed Spectrum in the Frequency Range from 0.0007 to 900 Cycles per Hour. Van der Hoven used data measured at different heights between 91 and 125 meters above the ground, and represented the high frequency end of the spectrum with data from the peak hour of hurricane Connie. These facts suggest we should question the use of his power spectrum in the wind industry. During the USDA - Agricultural Research Service`s investigation of wind/diesel system power storage, using the appropriate wind speed power spectrum became a significant issue. We developed a power spectrum from 13 years of hourly average data, 1 year of 5 minute average data, and 2 particularly gusty day`s 1 second average data all collected at a height of 10 meters. While the general shape is similar to the Van der Hoven spectrum, few of his peaks were found in the Bushland spectrum. While higher average wind speeds tend to suggest higher amplitudes in the high frequency end of the spectrum, this is not always true. Also, the high frequency end of the spectrum is not accurately described by simple wind statistics such as standard deviation and turbulence intensity. 2 refs., 5 figs., 1 tab.

  14. Optimization of powered Stirling heat engine with finite speed thermodynamics

    International Nuclear Information System (INIS)

    Ahmadi, Mohammad H.; Ahmadi, Mohammad Ali; Pourfayaz, Fathollah; Bidi, Mokhtar; Hosseinzade, Hadi; Feidt, Michel

    2016-01-01

    Highlights: • Based on finite speed method and direct method, the optimal performance is investigated. • The effects of major parameters on the optimal performance are investigated. • The accuracy of the results was compared with previous works. - Abstract: Popular thermodynamic analyses including finite time thermodynamic analysis was lately developed based upon external irreversibilities while internal irreversibilities such as friction, pressure drop and entropy generation were not considered. The aforementioned disadvantage reduces the reliability of the finite time thermodynamic analysis in the design of an accurate Stirling engine model. Consequently, the finite time thermodynamic analysis could not sufficiently satisfy researchers for implementing in design and optimization issues. In this study, finite speed thermodynamic analysis was employed instead of finite time thermodynamic analysis for studying Stirling heat engine. The finite speed thermodynamic analysis approach is based on the first law of thermodynamics for a closed system with finite speed and the direct method. The effects of heat source temperature, regenerating effectiveness, volumetric ratio, piston stroke as well as rotational speed are included in the analysis. Moreover, maximum output power in optimal rotational speed was calculated while pressure losses in the Stirling engine were systematically considered. The result reveals the accuracy and the reliability of the finite speed thermodynamic method in thermodynamic analysis of Stirling heat engine. The outcomes can help researchers in the design of an appropriate and efficient Stirling engine.

  15. Short-Term Wind Speed Forecasting for Power System Operations

    KAUST Repository

    Zhu, Xinxin

    2012-04-01

    The emphasis on renewable energy and concerns about the environment have led to large-scale wind energy penetration worldwide. However, there are also significant challenges associated with the use of wind energy due to the intermittent and unstable nature of wind. High-quality short-term wind speed forecasting is critical to reliable and secure power system operations. This article begins with an overview of the current status of worldwide wind power developments and future trends. It then reviews some statistical short-term wind speed forecasting models, including traditional time series approaches and more advanced space-time statistical models. It also discusses the evaluation of forecast accuracy, in particular, the need for realistic loss functions. New challenges in wind speed forecasting regarding ramp events and offshore wind farms are also presented. © 2012 The Authors. International Statistical Review © 2012 International Statistical Institute.

  16. Reactive power control methods for improved reliability of wind power inverters under wind speed variations

    DEFF Research Database (Denmark)

    Ma, Ke; Liserre, Marco; Blaabjerg, Frede

    2012-01-01

    method to relieve the thermal cycling of power switching devices under severe wind speed variations, by circulating reactive power among the parallel power converters in a WTS or among the WTS's in a wind park. The amount of reactive power is adjusted to limit the junction temperature fluctuation...

  17. High-speed adaptive contact-mode atomic force microscopy imaging with near-minimum-force

    International Nuclear Information System (INIS)

    Ren, Juan; Zou, Qingze

    2014-01-01

    In this paper, an adaptive contact-mode imaging approach is proposed to replace the traditional contact-mode imaging by addressing the major concerns in both the speed and the force exerted to the sample. The speed of the traditional contact-mode imaging is largely limited by the need to maintain precision tracking of the sample topography over the entire imaged sample surface, while large image distortion and excessive probe-sample interaction force occur during high-speed imaging. In this work, first, the image distortion caused by the topography tracking error is accounted for in the topography quantification. Second, the quantified sample topography is utilized in a gradient-based optimization method to adjust the cantilever deflection set-point for each scanline closely around the minimal level needed for maintaining stable probe-sample contact, and a data-driven iterative feedforward control that utilizes a prediction of the next-line topography is integrated to the topography feeedback loop to enhance the sample topography tracking. The proposed approach is demonstrated and evaluated through imaging a calibration sample of square pitches at both high speeds (e.g., scan rate of 75 Hz and 130 Hz) and large sizes (e.g., scan size of 30 μm and 80 μm). The experimental results show that compared to the traditional constant-force contact-mode imaging, the imaging speed can be increased by over 30 folds (with the scanning speed at 13 mm/s), and the probe-sample interaction force can be reduced by more than 15% while maintaining the same image quality

  18. High-speed adaptive contact-mode atomic force microscopy imaging with near-minimum-force

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Juan; Zou, Qingze, E-mail: qzzou@rci.rutgers.edu [Department of Mechanical and Aerospace Engineering, Rutgers University, 98 Brett Rd, Piscataway, New Jersey 08854 (United States)

    2014-07-15

    In this paper, an adaptive contact-mode imaging approach is proposed to replace the traditional contact-mode imaging by addressing the major concerns in both the speed and the force exerted to the sample. The speed of the traditional contact-mode imaging is largely limited by the need to maintain precision tracking of the sample topography over the entire imaged sample surface, while large image distortion and excessive probe-sample interaction force occur during high-speed imaging. In this work, first, the image distortion caused by the topography tracking error is accounted for in the topography quantification. Second, the quantified sample topography is utilized in a gradient-based optimization method to adjust the cantilever deflection set-point for each scanline closely around the minimal level needed for maintaining stable probe-sample contact, and a data-driven iterative feedforward control that utilizes a prediction of the next-line topography is integrated to the topography feeedback loop to enhance the sample topography tracking. The proposed approach is demonstrated and evaluated through imaging a calibration sample of square pitches at both high speeds (e.g., scan rate of 75 Hz and 130 Hz) and large sizes (e.g., scan size of 30 μm and 80 μm). The experimental results show that compared to the traditional constant-force contact-mode imaging, the imaging speed can be increased by over 30 folds (with the scanning speed at 13 mm/s), and the probe-sample interaction force can be reduced by more than 15% while maintaining the same image quality.

  19. Comparison of performances of full-speed turbine and half-speed turbine for nuclear power plants

    International Nuclear Information System (INIS)

    Wang Hu; Zhang Weihong; Zhang Qiang; Li Shaohua

    2010-01-01

    The steam turbines of nuclear power plants can be divided into the full-speed turbine and half-speed turbine. Different speed leads to differences in many aspects. Therefore, the rational speed is the key point in the selection of steam turbines. This paper contrasts the economy between the half-speed turbine and full-speed turbine, by calculating the relative internal efficiency of half-speed and full-speed steam turbines with the typical level of 1000 megawatt. At the same time, this paper also calculate the relative speed of high speed water drops in the last stage blade of half-speed turbine and full-speed turbine, to contrast the water erosion between the half-speed turbine and full-speed turbine. The results show that the relative internal efficiency of half-speed turbine is higher than that of the full-speed turbine, and that the security especially the ability of preventing water erosion of half-speed turbine is better than that of the full-speed turbine. (authors)

  20. A Neural Network Controller for Variable-Speed Variable-Pitch Wind Energy Conversion Systems Using Generalized Minimum Entropy Criterion

    Directory of Open Access Journals (Sweden)

    Mifeng Ren

    2014-01-01

    Full Text Available This paper considers the neural network controller design problem for variable pitch wind energy conversion systems (WECS with non-Gaussian wind speed disturbances in the stochastic distribution control framework. The approach here is used to directly model the unknown control law based on a fixed neural network (the number of layers and nodes in a neural network is fixed without the need to construct a separate model for the WECS. In order to characterize the randomness of the WECS, a generalized minimum entropy criterion is established to train connection weights of the neural network. For the train purpose, both kernel density estimation method and sliding window technique are adopted to estimate the PDF of tracking error and entropies. Due to the unknown process dynamics, the gradient of the objective function in a gradient-descent-type algorithm is estimated using an incremental perturbation method. The proposed approach is illustrated on a simulated WECS with non-Gaussian wind speed.

  1. Minimum power requirement for environmental control of aircraft

    International Nuclear Information System (INIS)

    Ordonez, Juan Carlos; Bejan, Adrian

    2003-01-01

    This paper addresses two basic issues in the thermodynamic optimization of environmental control systems (ECS) for aircraft: realistic limits for the minimal power requirement, and design features that facilitate operation at minimal power consumption. Four models are proposed and optimized. In the first, the ECS operates reversibly, the air stream in the cabin is mixed to one temperature, and the cabin experiences heat transfer with the ambient, across its insulation. The cabin temperature is fixed. In the second model, the fixed cabin temperature is assigned to the internal solid surfaces of the cabin, and a thermal resistance separates these surfaces from the air mixed in the cabin. In the third model, the ECS operates irreversibly, based on the bootstrap air cycle. The fourth model combines the ECS features of the third model with the cabin-environment interaction features of the second model. It is shown that in all models the temperature of the air stream that the ECS delivers to the cabin can be optimized for operation at minimal power. The effect of other design parameters and flying conditions is documented. The optimized air delivery temperature is relatively insensitive to the complexity of the model; for example, it is insensitive to the size of the heat exchanger used in the bootstrap air cycle. This study adds to the view that robustness is a characteristic of optimized complex flow systems, and that thermodynamic optimization results can be used for orientation in the pursuit of more complex and realistic designs

  2. Finding the Energy Efficient Curve: Gate Sizing for Minimum Power under Delay Constraints

    Directory of Open Access Journals (Sweden)

    Yoni Aizik

    2011-01-01

    Full Text Available A design scenario examined in this paper assumes that a circuit has been designed initially for high speed, and it is redesigned for low power by downsizing of the gates. In recent years, as power consumption has become a dominant issue, new optimizations of circuits are required for saving energy. This is done by trading off some speed in exchange for reduced power. For each feasible speed, an optimization problem is solved in this paper, finding new sizes for the gates such that the circuit satisfies the speed goal while dissipating minimal power. Energy/delay gain (EDG is defined as a metric to quantify the most efficient tradeoff. The EDG of the circuit is evaluated for a range of reduced circuit speeds, and the power-optimal gate sizes are compared with the initial sizes. Most of the energy savings occur at the final stages of the circuits, while the largest relative downsizing occurs in middle stages. Typical tapering factors for power efficient circuits are larger than those for speed-optimal circuits. Signal activity and signal probability affect the optimal gate sizes in the combined optimization of speed and power.

  3. On the minimum circulating power of steady state tokamaks

    International Nuclear Information System (INIS)

    Itoh, K.; Itoh, S.; Fukuyama, A.; Yagi, M.

    1995-07-01

    Circulating power for the sustenance and profile control of the steady state tokamak plasmas is discussed. The simultaneous fulfillment of the MHD stability at high beta value, the improved confinement and the stationary equilibrium requires the rotation drive as well as the current drive. In addition to the current drive efficiency, the efficiency for the rotation drive is investigated. The direct rotation drive by the external torque, such as the case of beam injection, is not efficient enough. The mechanism and the magnitude of the spontaneous plasma rotation are studied. (author)

  4. Minimum-Voltage Vector Injection Method for Sensorless Control of PMSM for Low-Speed Operations

    DEFF Research Database (Denmark)

    Xie, Ge; Lu, Kaiyuan; Kumar, Dwivedi Sanjeet

    2016-01-01

    In this paper, a simple signal injection method is proposed for sensorless control of PMSM at low speed, which ideally requires one voltage vector only for position estimation. The proposed method is easy to implement resulting in low computation burden. No filters are needed for extracting...... may also be further developed to inject two opposite voltage vectors to reduce the effects of inverter voltage error on the position estimation accuracy. The effectiveness of the proposed method is demonstrated by comparing with other sensorless control method. Theoretical analysis and experimental...

  5. Factors affecting speed in human-powered vehicles.

    Science.gov (United States)

    White, A P

    1994-10-01

    It is shown how to derive the appropriate cubic equation relating power and the effects of friction, gradient and wind resistance on the speed of a human-powered vehicle (HPV). The effects of gradient and wind resistance are explored for parameters representing a typical racing cyclist. The principal conclusion may be summarized as follows: for optimum performance in a time trial, there should be no wind and the course should be level. Any deviation from these conditions will produce a decrement in performance.

  6. Power system integration and control of variable speed wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Eek, Jarle

    2009-12-15

    A wind power plant is a highly dynamic system that dependent on the type of technology requires a number of automatic control loops. This research deals with modelling, control and analysis related to power system integration of variable speed, pitch controlled wind turbines. All turbine components have been modelled and implemented in the power system simulation program SIMPOW, and a description of the modelling approach for each component is given. The level of model detail relates to the classical modelling of power system components for power system stability studies, where low frequency oscillations are of special importance. The wind turbine model includes a simplified representation of the developed rotor torque and the thrust force based on C{sub p-} and C{sub t} characteristic curves. The mechanical system model represents the fundamental torsional mode and the first mode of blades and tower movements. Two generator technologies have been investigated. The doubly fed induction generator (DFIG) and the stator converter interfaced permanent magnet synchronous generator (PMSG). A simplified model of a 2 level voltage source converter is used for both machine types. The generator converter controllers have been given special attention. All model components are linearized for the purpose of control system design and power system interaction related to small signal stability analysis. Different control strategies discussed in the literature have been investigated with regard to power system interaction aspects. All control parameters are identified using the internal model control approach. The analysis is focused on three main areas: 1. Identification of low damped oscillatory modes. This is carried out by the establishment and discussion of wind turbine modelling. 2. Interaction between control loops. A systematic approach is presented in order to analyse the influence of control loops used in variable speed wind turbines. 3.Impact on power system performance

  7. An asymptotically unbiased minimum density power divergence estimator for the Pareto-tail index

    DEFF Research Database (Denmark)

    Dierckx, Goedele; Goegebeur, Yuri; Guillou, Armelle

    2013-01-01

    We introduce a robust and asymptotically unbiased estimator for the tail index of Pareto-type distributions. The estimator is obtained by fitting the extended Pareto distribution to the relative excesses over a high threshold with the minimum density power divergence criterion. Consistency...

  8. High speed micromachining with high power UV laser

    Science.gov (United States)

    Patel, Rajesh S.; Bovatsek, James M.

    2013-03-01

    Increasing demand for creating fine features with high accuracy in manufacturing of electronic mobile devices has fueled growth for lasers in manufacturing. High power, high repetition rate ultraviolet (UV) lasers provide an opportunity to implement a cost effective high quality, high throughput micromachining process in a 24/7 manufacturing environment. The energy available per pulse and the pulse repetition frequency (PRF) of diode pumped solid state (DPSS) nanosecond UV lasers have increased steadily over the years. Efficient use of the available energy from a laser is important to generate accurate fine features at a high speed with high quality. To achieve maximum material removal and minimal thermal damage for any laser micromachining application, use of the optimal process parameters including energy density or fluence (J/cm2), pulse width, and repetition rate is important. In this study we present a new high power, high PRF QuasarR 355-40 laser from Spectra-Physics with TimeShiftTM technology for unique software adjustable pulse width, pulse splitting, and pulse shaping capabilities. The benefits of these features for micromachining include improved throughput and quality. Specific example and results of silicon scribing are described to demonstrate the processing benefits of the Quasar's available power, PRF, and TimeShift technology.

  9. Experimental evaluation of the power balance model of speed skating.

    Science.gov (United States)

    de Koning, Jos J; Foster, Carl; Lampen, Joanne; Hettinga, Floor; Bobbert, Maarten F

    2005-01-01

    Prediction of speed skating performance with a power balance model requires assumptions about the kinetics of energy production, skating efficiency, and skating technique. The purpose of this study was to evaluate these parameters during competitive imitations for the purpose of improving model predictions. Elite speed skaters (n = 8) performed races and submaximal efficiency tests. External power output (P(o)) was calculated from movement analysis and aerodynamic models and ice friction measurements. Aerobic kinetics was calculated from breath-by-breath oxygen uptake (Vo(2)). Aerobic power (P(aer)) was calculated from measured skating efficiency. Anaerobic power (P(an)) kinetics was determined by subtracting P(aer) from P(o). We found gross skating efficiency to be 15.8% (1.8%). In the 1,500-m event, the kinetics of P(an) was characterized by a first-order system as P(an) = 88 + 556e(-0.0494t) (in W, where t is time). The rate constant for the increase in P(aer) was -0.153 s(-1), the time delay was 8.7 s, and the peak P(aer) was 234 W; P(aer) was equal to 234[1 - e(-0.153(t-8.7))] (in W). Skating position changed with preextension knee angle increasing and trunk angle decreasing throughout the event. We concluded the pattern of P(aer) to be quite similar to that reported during other competitive imitations, with the exception that the increase in P(aer) was more rapid. The pattern of P(an) does not appear to fit an "all-out" pattern, with near zero values during the last portion of the event, as assumed in our previous model (De Koning JJ, de Groot G, and van Ingen Schenau GJ. J Biomech 25: 573-580, 1992). Skating position changed in ways different from those assumed in our previous model. In addition to allowing improved predictions, the results demonstrate the importance of observations in unique subjects to the process of model construction.

  10. Variability of Wind Speeds and Power over Europe

    Science.gov (United States)

    Tambke, J.; von Bremen, L.; de Decker, J.; Schmidt, M.; Steinfeld, G.; Wolff, J.-O.

    2010-09-01

    This study comprises two parts: First, we describe the vertical wind speed and turbulence profiles that result from our improved PBL scheme and compare it to observations and 1-dimensional approaches (Monin-Obukhov etc.). Second, we analyse the spatio-temporal correlations in our meso-scale simulations for the years 2004 to 2007 over entire Europe, with special focus on the Irish, North and Baltic Sea. 1.) Vertical Wind Speed Profiles The vertical wind profile above the sea has to be modelled with high accuracy for tip heights up to 160m in order to achieve precise wind resource assessments, to calculate loads and wakes of wind turbines as well as for reliable short-term wind power forecasts. We present an assessment of different models for wind profiles in unstable, neutral and stable thermal stratification. The meso-scale models comprise MM5, WRF and COSMO-EU (LME). Both COSMO-EU from the German Weather Service DWD and WRF use a turbulence closure of 2.5th order - and lead to similar results. Especially the limiting effect of low boundary layer heights on the wind shear in very stable stratification is well captured. In our new WRF-formulation for the mixing length in the Mellor-Yamada-Janjic (MYJ) parameterisation of the Planetary Boundary Layer (PBL-scheme), the master length scale itself depends on the Monin-Obukhov-Length as a parameter for the heat flux effects on the turbulent mixing. This new PBL-scheme shows a better performance for all weather conditions than the original MYJ-scheme. Apart from the low-boundary-layer-effect in very stable situations (which are seldom), standard Monin-Obukhov formulations in combination with the Charnock relation for the sea surface roughness show good agreement with the FINO1-data (German Bight). Interesting results were achieved with two more detailed micro-scale approaches: - the parameterization proposed by Pena, Gryning and Hasager [BLM 2008] that depends on the boundary layer height - our ICWP-model, were the flux

  11. Speed

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Speed. The rate of information transferred per second is the speed of the information. Measured in bits per second. Need for speed on the net: You-Tube phenomenon; IPTV; 3D Video telephony. Online gaming; HDTV.

  12. Potential minimum cost of electricity of superconducting coil tokamak power reactors

    International Nuclear Information System (INIS)

    Reid, R.L.; Peng, Y-K. M.

    1989-01-01

    The potential minimum cost of electricity (COE) for superconducting tokamak power reactors is estimated by increasing the physics (confinement, beta limit, bootstrap current fraction) and technology [neutral beam energy, toroidal field (TF) coil allowable stresses, divertor heat flux, superconducting coil critical field, critical temperature, and quench temperature rise] constraints far beyond those assumed for ITER until the point of diminishing returns is reached. A version of the TETRA systems code, calibrated with the ITER design and modified for power reactors, is used for this analysis, limiting this study to reactors with the same basic device configuration and costing algorithms as ITER. A minimum COE is reduced from >200 to about 80 mill/kWh when the allowable design constraints are raised to 2 times those of ITER. At 4 times the ITER allowables, a minimum COE of about 60 mill/kWh is obtained. The corresponding tokamak has a major radius of approximately 4 m, a plasma current close to 10 MA, an aspect ratio of 4, a confinement H- factor ≤3, a beta limit of approximately 2 times the first stability regime, a divertor heat flux of about 20 MW/m 2 , a Β max ≤ 18 T, and a TF coil average current density about 3 times that of ITER. The design constraints that bound the minimum COE are the allowable stresses in the TF coil, the neutral beam energy, and the 99% bootstrap current (essentially free current drive). 14 refs., 4 figs., 2 tabs

  13. The speed-curvature power law in Drosophila larval locomotion.

    Science.gov (United States)

    Zago, Myrka; Lacquaniti, Francesco; Gomez-Marin, Alex

    2016-10-01

    We report the discovery that the locomotor trajectories of Drosophila larvae follow the power-law relationship between speed and curvature previously found in the movements of human and non-human primates. Using high-resolution behavioural tracking in controlled but naturalistic sensory environments, we tested the law in maggots tracing different trajectory types, from reaching-like movements to scribbles. For most but not all flies, we found that the law holds robustly, with an exponent close to three-quarters rather than to the usual two-thirds found in almost all human situations, suggesting dynamic effects adding on purely kinematic constraints. There are different hypotheses for the origin of the law in primates, one invoking cortical computations, another viscoelastic muscle properties coupled with central pattern generators. Our findings are consistent with the latter view and demonstrate that the law is possible in animals with nervous systems orders of magnitude simpler than in primates. Scaling laws might exist because natural selection favours processes that remain behaviourally efficient across a wide range of neural and body architectures in distantly related species. © 2016 The Authors.

  14. Joint Antenna Selection and Precoding Optimization for Small-Cell Network with Minimum Power Consumption

    Directory of Open Access Journals (Sweden)

    Qiang Sun

    2017-01-01

    Full Text Available We focus on the power consumption problem for a downlink multiuser small-cell network (SCN considering both the quality of service (QoS and power constraints. First based on a practical power consumption model taking into account both the dynamic transmit power and static circuit power, we formulate and then transform the power consumption optimization problem into a convex problem by using semidefinite relaxation (SDR technique and obtain the optimal solution by the CVX tool. We further note that the SDR-based solution becomes infeasible for realistic implementation due to its heavy backhaul burden and computational complexity. To this end, we propose an alternative suboptimal algorithm which has low implementation overhead and complexity, based on minimum mean square error (MMSE precoding. Furthermore, we propose a distributed correlation-based antenna selection (DCAS algorithm combining with our optimization algorithms to reduce the static circuit power consumption for the SCN. Finally, simulation results demonstrate that our proposed suboptimal algorithm is very effective on power consumption minimization, with significantly reduced backhaul burden and computational complexity. Moreover, we show that our optimization algorithms with DCAS have less power consumption than the other benchmark algorithms.

  15. Research on H2 speed governor for diesel engine of marine power station

    Science.gov (United States)

    Huang, Man-Lei

    2007-09-01

    The frequency stability of a marine power system is determined by the dynamic characteristic of the diesel engine speed regulation system in a marine power station. In order to reduce the effect of load disturbances and improve the dynamic precision of a diesel engine speed governor, a controller was designed for a diesel engine speed regulation system using H2 control theory. This transforms the specifications of the system into a standard H2 control problem. Firstly, the mathematical model of a diesel engine speed regulation system using an H2 speed governor is presented. To counter external disturbances and model uncertainty, the design of an H2 speed governor rests on the problem of mixed sensitivity. Computer simulation verified that the H2 speed governor improves the dynamic precision of a system and the ability to adapt to load disturbances, thus enhancing the frequency stability of marine power systems.

  16. The Benefit of Variable-Speed Turbine Operation for Low Temperature Thermal Energy Power Recovery

    OpenAIRE

    Brasz, Joost J.

    2014-01-01

    This paper analyzes, given the large variation in turbine discharge pressure with changing ambient temperatures, whether variable-speed radial-inflow turbine operation has a similar benefit for Organic Rankine Cycle (ORC) power recovery systems as variable-speed centrifugal compression has for chiller applications. The benefit of variable-speed centrifugal compression over fixed-speed operation is a reduction in annual electricity consumption of almost 40 %. Air-conditioning systems are by ne...

  17. Short-Term Wind Speed Forecasting for Power System Operations

    KAUST Repository

    Zhu, Xinxin; Genton, Marc G.

    2012-01-01

    some statistical short-term wind speed forecasting models, including traditional time series approaches and more advanced space-time statistical models. It also discusses the evaluation of forecast accuracy, in particular, the need for realistic loss

  18. Fixed-speed and Variable-speed Pumped Storage Dispatch Model in Power Systems with High Renewable Penetration

    Directory of Open Access Journals (Sweden)

    Yuan Bo

    2018-01-01

    Full Text Available According to different operating characteristics of pumped storage fixed speed unit and variable speed unit, a joint dispatching model of pumped storage unit and other types of units based on mixed integer linear optimization is constructed. The model takes into account the operating conditions, reservoir capacity, cycle type and other pumped storage unit constraints, but also consider the frequent start and stop and the stability of the operation of the unit caused by the loss. Using the Cplex solver to solve the model, the empirical example of the provincial power grid shows that the model can effectively arrange the pumping storage speed and the dispatching operation of the variable speed unit under the precondition of economic life of the unit, and give full play to the function of peak shaving and accommodating new energy. Because of its more flexible regulation characteristics of power generation and pumping conditions, the variable speed unit can better improve the operating conditions of other units in the system and promote the new energy dissipation.

  19. Fixed-speed and Variable-speed Pumped Storage Dispatch Model in Power Systems with High Renewable Penetration

    Science.gov (United States)

    Yuan, Bo; Zong, Jin; Xu, Zhicheng

    2018-06-01

    According to different operating characteristics of pumped storage fixed speed unit and variable speed unit, a joint dispatching model of pumped storage unit and other types of units based on mixed integer linear optimization is constructed. The model takes into account the operating conditions, reservoir capacity, cycle type and other pumped storage unit constraints, but also consider the frequent start and stop and the stability of the operation of the unit caused by the loss. Using the Cplex solver to solve the model, the empirical example of the provincial power grid shows that the model can effectively arrange the pumping storage speed and the dispatching operation of the variable speed unit under the precondition of economic life of the unit, and give full play to the function of peak shaving and accommodating new energy. Because of its more flexible regulation characteristics of power generation and pumping conditions, the variable speed unit can better improve the operating conditions of other units in the system and promote the new energy dissipation.

  20. A Meteorological Information Mining-Based Wind Speed Model for Adequacy Assessment of Power Systems With Wind Power

    DEFF Research Database (Denmark)

    Guo, Yifei; Gao, Houlei; Wu, Qiuwei

    2017-01-01

    Accurate wind speed simulation is an essential prerequisite to analyze the power systems with wind power. A wind speed model considering meteorological conditions and seasonal variations is proposed in this paper. Firstly, using the path analysis method, the influence weights of meteorological...... systems with wind power. The assessment results of the modified IEEE-RTS79 and IEEE-RTS96 demonstrated the effectiveness and accuracy of the proposed model....

  1. Determination of minimum sample size for fault diagnosis of automobile hydraulic brake system using power analysis

    Directory of Open Access Journals (Sweden)

    V. Indira

    2015-03-01

    Full Text Available Hydraulic brake in automobile engineering is considered to be one of the important components. Condition monitoring and fault diagnosis of such a component is very essential for safety of passengers, vehicles and to minimize the unexpected maintenance time. Vibration based machine learning approach for condition monitoring of hydraulic brake system is gaining momentum. Training and testing the classifier are two important activities in the process of feature classification. This study proposes a systematic statistical method called power analysis to find the minimum number of samples required to train the classifier with statistical stability so as to get good classification accuracy. Descriptive statistical features have been used and the more contributing features have been selected by using C4.5 decision tree algorithm. The results of power analysis have also been verified using a decision tree algorithm namely, C4.5.

  2. Structural integrity of power generating speed bumps made of concrete foam composite

    Science.gov (United States)

    Syam, B.; Muttaqin, M.; Hastrino, D.; Sebayang, A.; Basuki, W. S.; Sabri, M.; Abda, S.

    2018-02-01

    In this paper concrete foam composite speed bumps were designed to generate electrical power by utilizing the movements of commuting vehicles on highways, streets, parking gates, and drive-thru station of fast food restaurants. The speed bumps were subjected to loadings generated by vehicles pass over the power generating mechanical system. In this paper, we mainly focus our discussion on the structural integrity of the speed bumps and discuss the electrical power generating speed bumps in another paper. One aspect of structural integrity is its ability to support designed loads without breaking and includes the study of past structural failures in order to prevent failures in future designs. The concrete foam composites were used for the speed bumps; the reinforcement materials are selected from empty fruit bunch of oil palm. In this study, the speed bump materials and structure were subjected to various tests to obtain its physical and mechanical properties. To analyze the structure stability of the speed bumps some models were produced and tested in our speed bump test station. We also conduct a FEM-based computer simulation to analyze stress responses of the speed bump structures. It was found that speed bump type 1 significantly reduced the radial voltage. In addition, the speed bump is equipped with a steel casing is also suitable for use as a component component in generating electrical energy.

  3. Modeling wind speed and wind power distributions in Rwanda

    Energy Technology Data Exchange (ETDEWEB)

    Safari, Bonfils [Department of Physics, National University of Rwanda, P.O. Box 117, Huye District, South Province (Rwanda)

    2011-02-15

    Utilization of wind energy as an alternative energy source may offer many environmental and economical advantages compared to fossil fuels based energy sources polluting the lower layer atmosphere. Wind energy as other forms of alternative energy may offer the promise of meeting energy demand in the direct, grid connected modes as well as stand alone and remote applications. Wind speed is the most significant parameter of the wind energy. Hence, an accurate determination of probability distribution of wind speed values is very important in estimating wind speed energy potential over a region. In the present study, parameters of five probability density distribution functions such as Weibull, Rayleigh, lognormal, normal and gamma were calculated in the light of long term hourly observed data at four meteorological stations in Rwanda for the period of the year with fairly useful wind energy potential (monthly hourly mean wind speed anti v{>=}2 m s{sup -1}). In order to select good fitting probability density distribution functions, graphical comparisons to the empirical distributions were made. In addition, RMSE and MBE have been computed for each distribution and magnitudes of errors were compared. Residuals of theoretical distributions were visually analyzed graphically. Finally, a selection of three good fitting distributions to the empirical distribution of wind speed measured data was performed with the aid of a {chi}{sup 2} goodness-of-fit test for each station. (author)

  4. Design of intelligent comfort control system with human learning and minimum power control strategies

    International Nuclear Information System (INIS)

    Liang, J.; Du, R.

    2008-01-01

    This paper presents the design of an intelligent comfort control system by combining the human learning and minimum power control strategies for the heating, ventilating and air conditioning (HVAC) system. In the system, the predicted mean vote (PMV) is adopted as the control objective to improve indoor comfort level by considering six comfort related variables, whilst a direct neural network controller is designed to overcome the nonlinear feature of the PMV calculation for better performance. To achieve the highest comfort level for the specific user, a human learning strategy is designed to tune the user's comfort zone, and then, a VAV and minimum power control strategy is proposed to minimize the energy consumption further. In order to validate the system design, a series of computer simulations are performed based on a derived HVAC and thermal space model. The simulation results confirm the design of the intelligent comfort control system. In comparison to the conventional temperature controller, this system can provide a higher comfort level and better system performance, so it has great potential for HVAC applications in the future

  5. A Rotating Speed Controller Design Method for Power Levelling by Means of Inertia Energy in Wind Power Systems

    DEFF Research Database (Denmark)

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

    2015-01-01

    Power fluctuation caused by wind speed variations may be harmful for the stability of the power system as well as the reliability of the wind power converter, since it may induce thermal excursions in the solder joints of the power modules. Using the wind turbine rotor inertia energy for power...... in the frequency domain for power leveling. Moreover, the impact of other parameters on power leveling, including the time constant of maximum power point tracking (MPPT) and the rotor inertia, are also studied. With the proposed optimal design, the power fluctuations are mitigated as much as possible, while...

  6. Conceptual design of planetary gearbox system for constant generator speed in hydro power plant

    Directory of Open Access Journals (Sweden)

    Bhargav

    2018-01-01

    Full Text Available Micro Hydro Power Plant (MHPP is emerging as one of the most clean, renewable and reliable energy technology for harnessing power. In MHPP hydro governors are avoided, that results in turbine speed fluctuation. MHPP requires either speed or torque amplification of generator for constant power generation. To achieve this, planetary gear transmission system is explored for MHPP due to its higher efficiency and compact size. A conceptual planetary gearbox system is developed for MHPP to maintain constant generator speed. The conceptual gearbox is designed, modelled and analysed using ADAMS software. Simulation results are found to be in close agreement with analytical results. Hence, conceptual design of planetary gearbox can be used to govern constant generator speed. In this paper, a MHPP which generate constant power of 5 kW at constant generator speed of 1490 rpm is analysed and validated

  7. Accounting for the speed shear in wind turbine power performance measurement

    DEFF Research Database (Denmark)

    Wagner, Rozenn

    the vertical wind shear and the turbulence intensity. The work presented in this thesis consists of the description and the investigation of a simple method to account for the wind speed shear in the power performance measurement. Ignoring this effect was shown to result in a power curve dependant on the shear...... for turbulence intensity suggested by Albers. The second method was found to be more suitable for normalising the power curve for the turbulence intensity. Using the equivalent wind speed accounting for the wind shear in the power performance measurement was shown to result in a more repeatable power curve than......The power curve of a wind turbine is the primary characteristic of the machine as it is the basis of the warranty for it power production. The current IEC standard for power performance measurement only requires the measurement of the wind speed at hub height and the air density to characterise...

  8. Modeling of the dynamics of wind to power conversion including high wind speed behavior

    DEFF Research Database (Denmark)

    Litong-Palima, Marisciel; Bjerge, Martin Huus; Cutululis, Nicolaos Antonio

    2016-01-01

    This paper proposes and validates an efficient, generic and computationally simple dynamic model for the conversion of the wind speed at hub height into the electrical power by a wind turbine. This proposed wind turbine model was developed as a first step to simulate wind power time series...... for power system studies. This paper focuses on describing and validating the single wind turbine model, and is therefore neither describing wind speed modeling nor aggregation of contributions from a whole wind farm or a power system area. The state-of-the-art is to use static power curves for the purpose...... of power system studies, but the idea of the proposed wind turbine model is to include the main dynamic effects in order to have a better representation of the fluctuations in the output power and of the fast power ramping especially because of high wind speed shutdowns of the wind turbine. The high wind...

  9. Statistical analysis of wind speed for electrical power generation in ...

    African Journals Online (AJOL)

    Also, the results have shown that Jos, Kano and Minna fall in class 4 and therefore suitable for both off grid and grid connected modes. In addition, the effects of c and k parameters on the probability distribution functions have been presented. Keywords: Wind speed - probability - density function – wind energy conversion ...

  10. 40 CFR 1042.140 - Maximum engine power, displacement, power density, and maximum in-use engine speed.

    Science.gov (United States)

    2010-07-01

    ... cylinders having an internal diameter of 13.0 cm and a 15.5 cm stroke length, the rounded displacement would... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Maximum engine power, displacement... Maximum engine power, displacement, power density, and maximum in-use engine speed. This section describes...

  11. Highly-stabilized power supply for synchrotron accelerators. High speed, low ripple power supply

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Kenji [Osaka Univ., Ibaraki (Japan). Research Center for Nuclear Physics; Kumada, Masayuki; Fukami, Kenji; Koseki, Shoichiro; Kubo, Hiroshi; Kanazawa, Toru

    1997-02-01

    In synchrotron accelerators, in order to utilize high energy beam effectively, those are operated by repeating acceleration and taking-out at short period. In order to accelerate by maintaining beam track stable, the tracking performance with the error less than 10{sup -3} in the follow-up of current is required for the power supply. Further, in order to maintain the intensity and uniformity of beam when it is taken out, very low ripple is required for output current. The power supply having such characteristics has been developed, and applied to the HIMAC and the SPring-8. As the examples of the application of synchrotrons, the accelerators for medical treatment and the generation of synchrotron radiation are described. As to the power supply for the deflection magnets and quadrupole magnets of synchrotron accelerators, the specifications of the main power supply, the method of reducing ripple, the method of improving tracking, and active filter control are reported. As to the test results, the measurement of current ripple and tracking error is shown. The lowering of ripple was enabled by common mode filter and the symmetrical connection of electromagnets, and high speed response was realized by the compensation for delay with active filter. (K.I.)

  12. Hour-Ahead Wind Speed and Power Forecasting Using Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Ying-Yi Hong

    2013-11-01

    Full Text Available Operation of wind power generation in a large farm is quite challenging in a smart grid owing to uncertain weather conditions. Consequently, operators must accurately forecast wind speed/power in the dispatch center to carry out unit commitment, real power scheduling and economic dispatch. This work presents a novel method based on the integration of empirical mode decomposition (EMD with artificial neural networks (ANN to forecast the short-term (1 h ahead wind speed/power. First, significant parameters for training the ANN are identified using the correlation coefficients. These significant parameters serve as inputs of the ANN. Owing to the volatile and intermittent wind speed/power, the historical time series of wind speed/power is decomposed into several intrinsic mode functions (IMFs and a residual function through EMD. Each IMF becomes less volatile and therefore increases the accuracy of the neural network. The final forecasting results are achieved by aggregating all individual forecasting results from all IMFs and their corresponding residual functions. Real data related to the wind speed and wind power measured at a wind-turbine generator in Taiwan are used for simulation. The wind speed forecasting and wind power forecasting for the four seasons are studied. Comparative studies between the proposed method and traditional methods (i.e., artificial neural network without EMD, autoregressive integrated moving average (ARIMA, and persistence method are also introduced.

  13. Power Control of Permanent Magnet Generator Based Variable Speed Wind Turbines

    DEFF Research Database (Denmark)

    Deng, Fujin; Chen, Zhe

    2009-01-01

    When the wind power accounts for a large portion of the grid, it will be required to regulate the active power and reactive power. This paper investigates a MWlevel variable speed wind turbine with a permanent magnet synchronous generator (PMSG). The power control capabilities of two kinds...... of control schemes conducted respectively on this wind turbine under two conditions, including rapid wind speed change and grids faults, are compared. The simulation study of the wind turbine system is conducted using PSCAD/EMTDC, and the results show the different power control capabilities of the two...

  14. Accounting for the speed shear in wind turbine power performance measurement

    DEFF Research Database (Denmark)

    Wagner, Rozenn; Courtney, Michael; Gottschall, Julia

    2011-01-01

    The current IEC standard for wind turbine power performance measurement only requires measurement of the wind speed at hub height assuming this wind speed to be representative for the whole rotor swept area. However, the power output of a wind turbine depends on the kinetic energy flux, which...... itself depends on the wind speed profile, especially for large turbines. Therefore, it is important to characterize the wind profile in front of the turbine, and this should be preferably achieved by measuring the wind speed over the vertical range between lower and higher rotor tips. In this paper, we...... describe an experiment in which wind speed profiles were measured in front of a multimegawatt turbine using a ground–based pulsed lidar. Ignoring the vertical shear was shown to overestimate the kinetic energy flux of these profiles, in particular for those deviating significantly from a power law profile...

  15. Accounting for the speed shear in wind turbine power performance measurement

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, R.

    2010-04-15

    The power curve of a wind turbine is the primary characteristic of the machine as it is the basis of the warranty for it power production. The current IEC standard for power performance measurement only requires the measurement of the wind speed at hub height and the air density to characterise the wind field in front of the turbine. However, with the growing size of the turbine rotors during the last years, the effect of the variations of the wind speed within the swept rotor area, and therefore of the power output, cannot be ignored any longer. Primary effects on the power performance are from the vertical wind shear and the turbulence intensity. The work presented in this thesis consists of the description and the investigation of a simple method to account for the wind speed shear in the power performance measurement. Ignoring this effect was shown to result in a power curve dependant on the shear condition, therefore on the season and the site. It was then proposed to use an equivalent wind speed accounting for the whole speed profile in front of the turbine. The method was first tested with aerodynamic simulations of a multi-megawatt wind turbine which demonstrated the decrease of the scatter in the power curve. A power curve defined in terms of this equivalent wind speed would be less dependant on the shear than the standard power curve. The equivalent wind speed method was then experimentally validated with lidar measurements. Two equivalent wind speed definitions were considered both resulting in the reduction of the scatter in the power curve. As a lidar wind profiler can measure the wind speed at several heights within the rotor span, the wind speed profile is described with more accuracy than with the power law model. The equivalent wind speed derived from measurements, including at least one measurement above hub height, resulted in a smaller scatter in the power curve than the equivalent wind speed derived from profiles extrapolated from measurements

  16. Waterberg coal characteristics and SO2 minimum emissions standards in South African power plants.

    Science.gov (United States)

    Makgato, Stanford S; Chirwa, Evans M Nkhalambayausi

    2017-10-01

    Key characteristics of coal samples from the supply stock to the newly commissioned South African National Power Utility's (Eskom's) Medupi Power Station - which receives its supply coal from the Waterberg coalfield in Lephalale (Limpopo Province, South Africa) - were evaluated. Conventional coal characterisation such as proximate and ultimate analysis as well as determination of sulphur forms in coal samples were carried out following the ASTM and ISO standards. Coal was classified as medium sulphur coal when the sulphur content was detected in the range 1.15-1.49 wt.% with pyritic sulphur (≥0.51 wt.%) and organic sulphur (≥0.49 wt.%) accounted for the bulk of the total sulphur in coal. Maceral analyses of coal showed that vitrinite was the dominant maceral (up to 51.8 vol.%), whereas inertinite, liptinite, reactive semifusinite and visible minerals occurred in proportions of 22.6 vol.%, 2.9 vol.%, 5.3 vol.% and 17.5 vol.%, respectively. Theoretical calculations were developed and used to predict the resultant SO 2 emissions from the combustion of the Waterberg coal in a typical power plant. The sulphur content requirements to comply with the minimum emissions standards of 3500 mg/Nm 3 and 500 mg/Nm 3 were found to be ≤1.37 wt.% and ≤0.20 wt.%, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Are the force characteristics of synchronous handcycling affected by speed and the method to impose power?

    NARCIS (Netherlands)

    Arnet, U.; van Drongelen, S.V.; van der Woude, L.H.V.; Veeger, H.E.J.

    2012-01-01

    Objective: To investigate the influence of exercise conditions (speed and method to impose power) on the applied force, force effectiveness and distribution of work during handcycling. Method: Ten able-bodied men performed handcycling on a treadmill. To test the effect of speed, subjects propelled

  18. Are the force characteristics of synchronous handcycling affected by speed and the method to impose power?

    NARCIS (Netherlands)

    Arnet, Ursina; van Drongelen, Stefan; Veeger, DirkJan H. E. J.; van der Woude, Lucas H. V.

    Objective: To investigate the influence of exercise conditions (speed and method to impose power) on the applied force, force effectiveness and distribution of work during handcycling. Method: Ten able-bodied men performed handcycling on a treadmill. To test the effect of speed, subjects propelled

  19. Topography of Slow Sigma Power during Sleep is Associated with Processing Speed in Preschool Children.

    Science.gov (United States)

    Doucette, Margaret R; Kurth, Salome; Chevalier, Nicolas; Munakata, Yuko; LeBourgeois, Monique K

    2015-11-04

    Cognitive development is influenced by maturational changes in processing speed, a construct reflecting the rapidity of executing cognitive operations. Although cognitive ability and processing speed are linked to spindles and sigma power in the sleep electroencephalogram (EEG), little is known about such associations in early childhood, a time of major neuronal refinement. We calculated EEG power for slow (10-13 Hz) and fast (13.25-17 Hz) sigma power from all-night high-density electroencephalography (EEG) in a cross-sectional sample of healthy preschool children (n = 10, 4.3 ± 1.0 years). Processing speed was assessed as simple reaction time. On average, reaction time was 1409 ± 251 ms; slow sigma power was 4.0 ± 1.5 μV²; and fast sigma power was 0.9 ± 0.2 μV². Both slow and fast sigma power predominated over central areas. Only slow sigma power was correlated with processing speed in a large parietal electrode cluster (p power predicted faster reaction time. Our findings indicate regional correlates between sigma power and processing speed that are specific to early childhood and provide novel insights into the neurobiological features of the EEG that may underlie developing cognitive abilities.

  20. Topography of Slow Sigma Power during Sleep is Associated with Processing Speed in Preschool Children

    Directory of Open Access Journals (Sweden)

    Margaret R. Doucette

    2015-11-01

    Full Text Available Cognitive development is influenced by maturational changes in processing speed, a construct reflecting the rapidity of executing cognitive operations. Although cognitive ability and processing speed are linked to spindles and sigma power in the sleep electroencephalogram (EEG, little is known about such associations in early childhood, a time of major neuronal refinement. We calculated EEG power for slow (10–13 Hz and fast (13.25–17 Hz sigma power from all-night high-density electroencephalography (EEG in a cross-sectional sample of healthy preschool children (n = 10, 4.3 ± 1.0 years. Processing speed was assessed as simple reaction time. On average, reaction time was 1409 ± 251 ms; slow sigma power was 4.0 ± 1.5 μV2; and fast sigma power was 0.9 ± 0.2 μV2. Both slow and fast sigma power predominated over central areas. Only slow sigma power was correlated with processing speed in a large parietal electrode cluster (p < 0.05, r ranging from −0.6 to −0.8, such that greater power predicted faster reaction time. Our findings indicate regional correlates between sigma power and processing speed that are specific to early childhood and provide novel insights into the neurobiological features of the EEG that may underlie developing cognitive abilities.

  1. A nonlinear dynamics approach for incorporating wind-speed patterns into wind-power project evaluation.

    Science.gov (United States)

    Huffaker, Ray; Bittelli, Marco

    2015-01-01

    Wind-energy production may be expanded beyond regions with high-average wind speeds (such as the Midwest U.S.A.) to sites with lower-average speeds (such as the Southeast U.S.A.) by locating favorable regional matches between natural wind-speed and energy-demand patterns. A critical component of wind-power evaluation is to incorporate wind-speed dynamics reflecting documented diurnal and seasonal behavioral patterns. Conventional probabilistic approaches remove patterns from wind-speed data. These patterns must be restored synthetically before they can be matched with energy-demand patterns. How to accurately restore wind-speed patterns is a vexing problem spurring an expanding line of papers. We propose a paradigm shift in wind power evaluation that employs signal-detection and nonlinear-dynamics techniques to empirically diagnose whether synthetic pattern restoration can be avoided altogether. If the complex behavior of observed wind-speed records is due to nonlinear, low-dimensional, and deterministic system dynamics, then nonlinear dynamics techniques can reconstruct wind-speed dynamics from observed wind-speed data without recourse to conventional probabilistic approaches. In the first study of its kind, we test a nonlinear dynamics approach in an application to Sugarland Wind-the first utility-scale wind project proposed in Florida, USA. We find empirical evidence of a low-dimensional and nonlinear wind-speed attractor characterized by strong temporal patterns that match up well with regular daily and seasonal electricity demand patterns.

  2. High-Speed, Low-Power ADC for Digital Beam Forming (DBF) Systems, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — In Phase 1, Ridgetop Group designed a high-speed, yet low-power silicon germanium (SiGe)-based, analog-to-digital converter (ADC) to be a key element for digital...

  3. High-Speed, Low-Power ADC for Digital Beam Forming (DBF) Systems, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Ridgetop Group will design a high-speed, low-power silicon germanium (SiGe)-based, analog-to-digital converter (ADC) to be a key element for digital beam forming...

  4. Modelling and control of variable speed wind turbines for power system studies

    DEFF Research Database (Denmark)

    Michalke, Gabriele; Hansen, Anca Daniela

    2010-01-01

    and implemented in the power system simulation tool DIgSILENT. Important issues like the fault ride-through and grid support capabilities of these wind turbine concepts are addressed. The paper reveals that advanced control of variable speed wind turbines can improve power system stability. Finally......, it will be shown in the paper that wind parks consisting of variable speed wind turbines can help nearby connected fixed speed wind turbines to ride-through grid faults. Copyright © 2009 John Wiley & Sons, Ltd.......Modern wind turbines are predominantly variable speed wind turbines with power electronic interface. Emphasis in this paper is therefore on the modelling and control issues of these wind turbine concepts and especially on their impact on the power system. The models and control are developed...

  5. statistical analysis of wind speed for electrical power generation

    African Journals Online (AJOL)

    HOD

    In order to predict and model the potential of any site, ... gamma, and Raleigh distributions for 8 locations in. Nigeria. ... probability density function is used to model the average power in ... mathematical expression of the Weibull distribution is.

  6. statistical analysis of wind speed for electrical power generation

    African Journals Online (AJOL)

    HOD

    sites are suitable for the generation of electrical energy. Also, the results ... Nigerian Journal of Technology (NIJOTECH). Vol. 36, No. ... parameter in the wind-power generation system. ..... [3] A. Zaharim, A. M Razali, R. Z Abidin, and K Sopian,.

  7. Dependence of the maximum power and wind speed

    Directory of Open Access Journals (Sweden)

    Florentiu Deliu

    2013-09-01

    Full Text Available The issue paper is to present renewable energy sources insisting mainly on wind energy. This source is analyzed in the context of Romania in particular and the EU in general. A turbine with horizontal axis is usually coupled with vessel power systems. Wind energy knows an increased growth rate. At the end of the paper are presented possible structure of coupled a wind to power systems.

  8. Relationship of the Functional Movement Screen In-Line Lunge to Power, Speed, and Balance Measures

    OpenAIRE

    Hartigan, Erin H.; Lawrence, Michael; Bisson, Brian M.; Torgerson, Erik; Knight, Ryan C.

    2014-01-01

    Background: The in-line lunge of the Functional Movement Screen (FMS) evaluates lateral stability, balance, and movement asymmetries. Athletes who score poorly on the in-line lunge should avoid activities requiring power or speed until scores are improved, yet relationships between the in-line lunge scores and other measures of balance, power, and speed are unknown. Hypothesis: (1) Lunge scores will correlate with center of pressure (COP), maximum jump height (MJH), and 36.6-meter sprint time...

  9. Power Maximization Control of Variable Speed Wind Generation System Using Permanent Magnet Synchronous Generator

    Science.gov (United States)

    Morimoto, Shigeo; Nakamura, Tomohiko; Takeda, Yoji

    This paper proposes the sensorless output power maximization control of the wind generation system. A permanent magnet synchronous generator (PMSG) is used as a variable speed generator in the proposed system. The generator torque is suitably controlled according to the generator speed and thus the power from a wind turbine settles down on the maximum power point by the proposed MPPT control method, where the information of wind velocity is not required. Moreover, the maximum available generated power is obtained by the optimum current vector control. The current vector of PMSG is optimally controlled according to the generator speed and the required torque in order to minimize the losses of PMSG considering the voltage and current constraints. The proposed wind power generation system can be achieved without mechanical sensors such as a wind velocity detector and a position sensor. Several experimental results show the effectiveness of the proposed control method.

  10. Gate Drive For High Speed, High Power IGBTs

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, M.N.; Cassel, R.L.; de Lamare, J.E.; Pappas, G.C.; /SLAC

    2007-06-18

    A new gate drive for high-voltage, high-power IGBTs has been developed for the SLAC NLC (Next Linear Collider) Solid State Induction Modulator. This paper describes the design and implementation of a driver that allows an IGBT module rated at 800A/3300V to switch up to 3000A at 2200V in 3{micro}S with a rate of current rise of more than 10000A/{micro}S, while still being short circuit protected. Issues regarding fast turn on, high de-saturation voltage detection, and low short circuit peak current will be presented. A novel approach is also used to counter the effect of unequal current sharing between parallel chips inside most high-power IGBT modules. It effectively reduces the collector-emitter peak current, and thus protects the IGBT from being destroyed during soft short circuit conditions at high di/dt.

  11. Gate Drive For High Speed, High Power IGBTs

    International Nuclear Information System (INIS)

    Nguyen, M.N.; Cassel, R.L.; de Lamare, J.E.; Pappas, G.C.; SLAC

    2007-01-01

    A new gate drive for high-voltage, high-power IGBTs has been developed for the SLAC NLC (Next Linear Collider) Solid State Induction Modulator. This paper describes the design and implementation of a driver that allows an IGBT module rated at 800A/3300V to switch up to 3000A at 2200V in 3(micro)S with a rate of current rise of more than 10000A/(micro)S, while still being short circuit protected. Issues regarding fast turn on, high de-saturation voltage detection, and low short circuit peak current will be presented. A novel approach is also used to counter the effect of unequal current sharing between parallel chips inside most high-power IGBT modules. It effectively reduces the collector-emitter peak current, and thus protects the IGBT from being destroyed during soft short circuit conditions at high di/dt

  12. FLC based adjustable speed drives for power quality enhancement

    Directory of Open Access Journals (Sweden)

    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.

  13. Dynamic Analysis of Fluid Power Drive-trains for Variable Speed Wind Turbines : A Parameter Study

    NARCIS (Netherlands)

    Jarquin Laguna, A.; Diepeveen, N.F.B.

    2013-01-01

    In the pursuit of making wind energy technology more economically attractive, the application of fluid power technology for the transmission of wind energy is being developed by several parties all over the world. This paper presents a dynamic model of a fluid power transmission for variable speed

  14. Thermal loading of wind power converter considering dynamics of wind speed

    DEFF Research Database (Denmark)

    Baygildina, Elvira; Peltoniemi, Pasi; Pyrhönen, Olli

    2013-01-01

    The thermal loading of power semiconductors is a crucial performance related to the reliability and cost of the wind power converter. However, the thermal loading impacts by the variation of wind speeds have not yet been clarified, especially when considering the aerodynamic behavior of the wind...... turbines. In this paper, the junction temperatures in the wind power converter are studied under not only steady state, but also turbulent wind speed conditions. The study is based on a 1.5 MW direct-driven turbine system with aerodynamic model described by Unsteady Blade Element Momentum Method (BEMM......), and the thermal stress of power devices is investigated from the frequency spectrum point of view of wind speed. It is concluded that because of the strong inertia effects by the aerodynamic behavior of wind turbines, thermal stress of the semiconductors is relatively more stable and only influenced by the low...

  15. Minimum cost solution of wind–photovoltaic based stand-alone power systems for remote consumers

    International Nuclear Information System (INIS)

    Kaldellis, J.K.; Zafirakis, D.; Kavadias, K.

    2012-01-01

    Renewable energy sources (RES) based stand-alone systems employing either wind or solar power and energy storage comprise a reliable energy alternative, on top of conventional diesel-electric generator sets, commonly used by remote consumers. However, such systems usually imply the need for oversizing and considerable energy storage requirements leading to relatively high costs. On the other hand, hybrid configurations that may exploit both wind and solar potential of a given area may considerably reduce energy storage capacity and improve the economic performance of the system. In this context, an integrated techno-economic methodology for the evaluation of hybrid wind–photovoltaic stand-alone power systems is currently developed, aiming at the designation of optimum configurations for a typical remote consumer, using economic performance criteria. For the problem investigation, the developed evaluation model is applied to four representative areas of the Greek territory with different wind potential characteristics in order to obtain optimum configurations on the basis of minimum initial investment, 10-year and 20-year total cost. According to the results obtained, the proposed solution is favorably compared with all other stand-alone energy alternatives, reflecting the ability of hybrid systems to adjust even in areas where the local RES potential is not necessarily of high quality. - Highlights: ► Wind- and PV-stand alone systems often imply use of extreme battery capacity. ► Hybrid wind–PV systems may reduce energy storage requirements and associated costs. ► An optimization methodology is developed, based on economic performance criteria. ► Methodology is applied to four Greek regions of different wind potential. ► Results obtained reflect the hybrid solution's advantages over other alternatives.

  16. A novel minimum cost maximum power algorithm for future smart home energy management

    Directory of Open Access Journals (Sweden)

    A. Singaravelan

    2017-11-01

    Full Text Available With the latest development of smart grid technology, the energy management system can be efficiently implemented at consumer premises. In this paper, an energy management system with wireless communication and smart meter are designed for scheduling the electric home appliances efficiently with an aim of reducing the cost and peak demand. For an efficient scheduling scheme, the appliances are classified into two types: uninterruptible and interruptible appliances. The problem formulation was constructed based on the practical constraints that make the proposed algorithm cope up with the real-time situation. The formulated problem was identified as Mixed Integer Linear Programming (MILP problem, so this problem was solved by a step-wise approach. This paper proposes a novel Minimum Cost Maximum Power (MCMP algorithm to solve the formulated problem. The proposed algorithm was simulated with input data available in the existing method. For validating the proposed MCMP algorithm, results were compared with the existing method. The compared results prove that the proposed algorithm efficiently reduces the consumer electricity consumption cost and peak demand to optimum level with 100% task completion without sacrificing the consumer comfort.

  17. A novel minimum cost maximum power algorithm for future smart home energy management.

    Science.gov (United States)

    Singaravelan, A; Kowsalya, M

    2017-11-01

    With the latest development of smart grid technology, the energy management system can be efficiently implemented at consumer premises. In this paper, an energy management system with wireless communication and smart meter are designed for scheduling the electric home appliances efficiently with an aim of reducing the cost and peak demand. For an efficient scheduling scheme, the appliances are classified into two types: uninterruptible and interruptible appliances. The problem formulation was constructed based on the practical constraints that make the proposed algorithm cope up with the real-time situation. The formulated problem was identified as Mixed Integer Linear Programming (MILP) problem, so this problem was solved by a step-wise approach. This paper proposes a novel Minimum Cost Maximum Power (MCMP) algorithm to solve the formulated problem. The proposed algorithm was simulated with input data available in the existing method. For validating the proposed MCMP algorithm, results were compared with the existing method. The compared results prove that the proposed algorithm efficiently reduces the consumer electricity consumption cost and peak demand to optimum level with 100% task completion without sacrificing the consumer comfort.

  18. A ROBUST CLUSTER HEAD SELECTION BASED ON NEIGHBORHOOD CONTRIBUTION AND AVERAGE MINIMUM POWER FOR MANETs

    Directory of Open Access Journals (Sweden)

    S.Balaji

    2015-06-01

    Full Text Available Mobile Adhoc network is an instantaneous wireless network that is dynamic in nature. It supports single hop and multihop communication. In this infrastructure less network, clustering is a significant model to maintain the topology of the network. The clustering process includes different phases like cluster formation, cluster head selection, cluster maintenance. Choosing cluster head is important as the stability of the network depends on well-organized and resourceful cluster head. When the node has increased number of neighbors it can act as a link between the neighbor nodes which in further reduces the number of hops in multihop communication. Promisingly the node with more number of neighbors should also be available with enough energy to provide stability in the network. Hence these aspects demand the focus. In weight based cluster head selection, closeness and average minimum power required is considered for purging the ineligible nodes. The optimal set of nodes selected after purging will compete to become cluster head. The node with maximum weight selected as cluster head. Mathematical formulation is developed to show the proposed method provides optimum result. It is also suggested that weight factor in calculating the node weight should give precise importance to energy and node stability.

  19. High speed and high functional inverter power supplies for plasma generation and control, and their performance

    International Nuclear Information System (INIS)

    Uesugi, Yoshihiko; Razzak, Mohammad A.; Kondo, Kenji; Kikuchi, Yusuke; Takamura, Shuichi; Imai, Takahiro; Toyoda, Mitsuhiro

    2003-01-01

    The Rapid development of high power and high speed semiconductor switching devices has led to their various applications in related plasma fields. Especially, a high speed inverter power supply can be used as an RF power source instead of conventional linear amplifiers and a power supply to control the magnetic field in a fusion plasma device. In this paper, RF thermal plasma production and plasma heating experiments are described emphasis placed on using a static induction transistor inverter at a frequency range between 200 kHz and 2.5 MHz as an RF power supply. Efficient thermal plasma production is achieved experimentally by using a flexible and easily operated high power semiconductor inverter power supply. Insulated gate bipolar transistor (IGBT) inverter power supplies driven by a high speed digital signal processor are applied as tokamak joule coil and vertical coil power supplies to control plasma current waveform and plasma equilibrium. Output characteristics, such as the arbitrary bipolar waveform generation of a pulse width modulation (PWM) inverter using digital signal processor (DSP) can be successfully applied to tokamak power supplies for flexible plasma current operation and fast position control of a small tokamak. (author)

  20. Perfection of badminton players’ speed-power fitness with the help of training means’ variable modules

    Directory of Open Access Journals (Sweden)

    I.V. Karatnyk

    2016-06-01

    Full Text Available Purpose: to determine effectiveness of badminton players’ speed power fitness program’s perfection at stage of specialized basic training with different variants of training means modules’ combination. Material: in experiment badminton players of 15-17 years’ age (from 1st sports grade to master of sports participated. The sportsmen were divided into three experimental groups (10 persons in each. The trainings were being conducted during 24 weeks by different variants of program. Results: we created different complexes of exercises, combined in three modules (every of each lasted eight week micro-cycles. Every module has more expressed meaningful parts (1 – speed, 2 – power, 3 – jumping. All modules were combined in program of badminton players’ speed power fitness perfection. For every experimental group we worked out distinguishing variant of modules’ combination in program (first variant – 1-2-3 modules; second – 2-3-1; third – 3-1-2. General duration of program was 24 week micro-cycles. Conclusions: we recommended some variants of variable modules’ combination for badminton players’ speed-power fitness perfection. With it, we can regard total influence on the following: speed-power endurance, work with support on own body, quick movements of different body links.

  1. Deepening structural reform, and speeding up self-reliant nuclear power development

    International Nuclear Information System (INIS)

    Wang Binghua

    2010-01-01

    Combining the implementation practices of the strategy on self-reliant development of the third generation nuclear power plant, the paper set forth that speeding up self-reliant nuclear power development has strategic significance to the national economy and the people's livelihood, which need further deepening structural reform and nuclear power structural reform with an aim to enhance the international competitiveness of China's nuclear industry. (author)

  2. Virtual Refrigerant Mass Flow and Power Sensors for Variable-Speed Compressors

    OpenAIRE

    Kim, Woohyun; Braun, James E.

    2012-01-01

    The use of variable-speed compressors in heat pumps and air conditioners has increased in recent years in order to improve comfort and energy efficiency. At the same time, there is a trend towards embedding more sensors in this type of equipment to facilitate real-time energy monitoring and diagnostics. Although compressor mass flow rate and power consumption are useful indices for performance monitoring and diagnostics, they are expensive to measure. The virtual variable-speed compressor sen...

  3. Analysis of transport logistics and routing requirements for radioactive waste management systems with respect to a minimum power scenario

    International Nuclear Information System (INIS)

    James, I.A.

    1984-10-01

    This report assesses the transport logistics associated with disposal of intermediate-level radioactive waste, as generated by CEGB, SSEB, UKAEA and BNFL, in accordance with a 'Minimum Power Scenario'. Transport by road and rail is analysed, as in previous reports; use of coastal shipping however has not been included but has been replaced with a combined road/rail option. (author)

  4. Modeling the Power Variability of Core Speed Scaling on Homogeneous Multicore Systems

    Directory of Open Access Journals (Sweden)

    Zhihui Du

    2017-01-01

    Full Text Available We describe a family of power models that can capture the nonuniform power effects of speed scaling among homogeneous cores on multicore processors. These models depart from traditional ones, which assume that individual cores contribute to power consumption as independent entities. In our approach, we remove this independence assumption and employ statistical variables of core speed (average speed and the dispersion of the core speeds to capture the comprehensive heterogeneous impact of subtle interactions among the underlying hardware. We systematically explore the model family, deriving basic and refined models that give progressively better fits, and analyze them in detail. The proposed methodology provides an easy way to build power models to reflect the realistic workings of current multicore processors more accurately. Moreover, unlike the existing lower-level power models that require knowledge of microarchitectural details of the CPU cores and the last level cache to capture core interdependency, ours are easier to use and scalable to emerging and future multicore architectures with more cores. These attributes make the models particularly useful to system users or algorithm designers who need a quick way to estimate power consumption. We evaluate the family of models on contemporary x86 multicore processors using the SPEC2006 benchmarks. Our best model yields an average predicted error as low as 5%.

  5. Special speed-power training as the basis of technical skillfulness improvement in sport aerobic

    Directory of Open Access Journals (Sweden)

    T.V. Moshenska

    2015-12-01

    Full Text Available Purpose: to theoretically work out and experimentally substantiate effectiveness of authors’ methodic of speed-power qualities’ training in sport aerobic. Material: 20 sportsmen participated in the research: boys and girls of 8-12 years’ age. Assessment of speed-power fitness was conducted by results of commonly accepted tests, applied in sport practice. Results: we have developed complexes of jump exercises, which envisage varying of conditions of exercises’ fulfillment at the account of pushing conditions (jumps in depth, jumps over obstacles and jumps on elevated platforms. When fulfilling jumps in motion the main was achievement of maximal height with fixing of jump’s form in flight. Conclusions: we offer six complexes of exercises for speed-power training in sport aerobic. These complexes are recommended to be fulfilled at the end of preparatory part of training session during 15-20 minutes.

  6. Evaluation of the power consumption of a high-speed parallel robot

    Science.gov (United States)

    Han, Gang; Xie, Fugui; Liu, Xin-Jun

    2018-06-01

    An inverse dynamic model of a high-speed parallel robot is established based on the virtual work principle. With this dynamic model, a new evaluation method is proposed to measure the power consumption of the robot during pick-and-place tasks. The power vector is extended in this method and used to represent the collinear velocity and acceleration of the moving platform. Afterward, several dynamic performance indices, which are homogenous and possess obvious physical meanings, are proposed. These indices can evaluate the power input and output transmissibility of the robot in a workspace. The distributions of the power input and output transmissibility of the high-speed parallel robot are derived with these indices and clearly illustrated in atlases. Furtherly, a low-power-consumption workspace is selected for the robot.

  7. CMOS analog integrated circuits high-speed and power-efficient design

    CERN Document Server

    Ndjountche, Tertulien

    2011-01-01

    High-speed, power-efficient analog integrated circuits can be used as standalone devices or to interface modern digital signal processors and micro-controllers in various applications, including multimedia, communication, instrumentation, and control systems. New architectures and low device geometry of complementary metaloxidesemiconductor (CMOS) technologies have accelerated the movement toward system on a chip design, which merges analog circuits with digital, and radio-frequency components. CMOS: Analog Integrated Circuits: High-Speed and Power-Efficient Design describes the important tren

  8. Experimental research of variable rotation speed ICE-based electric power station

    Directory of Open Access Journals (Sweden)

    Dar’enkov Andrey

    2017-01-01

    Full Text Available Developing variable rotation speed ICE-based stand-alone electric power stations which can supply distant regions and autonomous objects with electricity are of scientific interest due to the insufficient study. The relevance of developing such electric power stations is determined by their usage is to provide a significant fuel saving as well as increase ICE motor service life. The article describes the electric station of autonomous objects with improved fuel economy. The article describes multivariate characteristic. Multivariate characteristic shows the optimal frequency of rotation of the internal combustion engine. At this rotational speed there is the greatest fuel economy.

  9. Model and simulation of the hydraulic turbine speed regulator of the Atucha I nuclear power plant

    International Nuclear Information System (INIS)

    Copparoni, G.; Etchepareborda, A.; Urrutia, G.

    1992-01-01

    The hydraulics turbines of Atucha I Nuclear Power Plant takes advantage of condenser cooling water level difference between the plant and the river to recover about 2,5 MW e. It also supplies emergency power until diesel generators start up. Speed regulation is needed due to the transients that during this process occur. The purpose is to minimize the diesels start up time, and to avoid overshoots on the internal grid frequency. The hydraulic turbine, its speed regulator and the electric system associated with this transient have been modeled. The models and some simulation results are presented in this work. (author)

  10. The independent effects of speed and propulsive force on joint power generation in walking.

    Science.gov (United States)

    Browne, Michael G; Franz, Jason R

    2017-04-11

    Walking speed is modulated using propulsive forces (F P ) during push-off and both preferred speed and F P decrease with aging. However, even prior to walking slower, reduced F P may be accompanied by potentially unfavorable changes in joint power generation. For example, compared to young adults, older adults exhibit a redistribution of mechanical power generation from the propulsive plantarflexor muscles to more proximal muscles acting across the knee and hip. Here, we used visual biofeedback based on real-time F P measurements to decouple and investigate the interaction between joint-level coordination, whole-body F P , and walking speed. 12 healthy young subjects walked on a dual-belt instrumented treadmill at a range of speeds (0.9-1.3m/s). We immediately calculated the average F P from each speed. Subjects then walked at 1.3m/s while completing a series of biofeedback trials with instructions to match their instantaneous F P to their averaged F P from slower speeds. Walking slower decreased F P and total positive joint work with little effect on relative joint-level contributions. Conversely, subjects walked at a constant speed with reduced F P , not by reducing total positive joint work, but by redistributing the mechanical demands of each step from the plantarflexor muscles during push-off to more proximal leg muscles during single support. Interestingly, these naturally emergent joint- and limb-level biomechanical changes, in the absence of neuromuscular constraints, resemble those due to aging. Our findings provide important reference data to understand the presumably complex interactions between joint power generation, whole-body F P , and walking speed in our aging population. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Rotor aerodynamic power limits at low tip speed ratio using CFD

    International Nuclear Information System (INIS)

    Mikkelsen, Robert F; Sarmast, Sasan; Henningson, Dan; Sørensen, Jens N

    2014-01-01

    When investigating limits of rotor aerodynamic models, the Betz limit serves as a solid marker of an upper limit which no model should be able to exceed. A century ago Joukowsky (1912) proposed a rotor aerodynamic model utilizing a rotating actuator disc with a constant circulation. This model has since then been the subject of much controversy as it predicts a power performance that for all tip speed ratios exceeds the Betz limit and which goes to infinity when the tip speed ratio goes to zero. Recently, it was demonstrated that the Joukowsky model is fully consistent with the inviscid Euler equations and that the apparent inconsistency partly can be explained by the lack of viscous effects (Sprensen and van Kuik [4]). However, even including a term to account for the effect of viscosity at small tip speed ratios, the model still predicts a power yield that exceeds the Betz limit. In the present work we study in detail, using a CFD actuator line model, the flow behavior for rotors at small tip speed ratios. It is shown that the excessive swirl appearing towards the rotor center at small tip speed ratios generates vortex breakdown, causing a recirculating zone in the wake that limits the power yield of the rotor. The appearance of vortex breakdown has a similar effect on the flow behavior as the vortex ring state that usually appears at higher tip speed ratios. Limits to where vortex breakdown might occur with tip speed ratio and rotor loading as parameter are investigated and presented in the paper. The limits found correspond to well-known criterion for vortex breakdown onset for swirling flows in general. By applying a criterion for vortex breakdown in combination with the general momentum theory, the power performance always stays below the Betz limit

  12. Changes of indicators of high-speed and high-speed and power preparedness at volleyball players of 12–13 years old

    Directory of Open Access Journals (Sweden)

    Oleg Shevchenko

    2016-04-01

    Full Text Available Purpose: to define changes of indicators of high-speed and high-speed and power preparedness of volleyball players of 12–13 years old. Material & Methods: the test exercises, which are recommended by the training program of CYSS on volleyball, were used for the definition of the level of development of high-speed and high-speed and power abilities of volleyball players. 25 young volleyball players from the group of the previous basic preparation took part in the experiment. Sports experience of sportsmen is 3–4 years. The analysis of scientifically-methodical literature, pedagogical testing, pedagogical experiment, methods of mathematical statistics were carried out. Results: the analyzed level of high-speed and high-speed and power abilities of volleyball players. Conclusions: the results had reliable changes (t=2,2–2,4 at р<0,05 of the level of high-speed and high-speed and power abilities of volleyball players of 12–13years old in the experimental group at the end of the experiment, except run on 30 m that demonstrates a positive influence of application of special exercises in the educational-training process.

  13. Effect of ranibizumab on high-speed indocyanine green angiography and minimum intensity projection optical coherence tomography findings in neovascular age-related macular degeneration.

    Science.gov (United States)

    Nicholson, Benjamin P; Nigam, Divya; Toy, Brian; Stetson, Paul F; Agrón, Elvira; Jacobs-El, Naima; Cunningham, Denise; Cukras, Catherine; Wong, Wai; Wiley, Henry; Chew, Emily; Ferris, Frederick; Meyerle, Catherine B

    2015-01-01

    The purpose of this 1-year prospective study was to investigate how induction/pro re nata ranibizumab intravitreal treatment of eyes with neovascular age-related macular degeneration affects the anatomy of choroidal neovascularization (CNV) and the overlying outer retinal tissue. High-speed indocyanine green (HS-ICG) angiography measurements provided quantification of the CNV size in 60 patients followed for 1 year. Minimum intensity projection optical coherence tomography (MinIP OCT), a novel algorithm assessing minimum optical intensity between the internal limiting membrane and retinal pigment epithelium, measured the area of outer retinal disruption overlying the CNV. Fluorescein angiography was also assessed to evaluate late retinal leakage. After 1 year, the mean area of CNV measured with indocyanine green angiography decreased by 5.8%. The mean area of MinIP OCT of outer retinal disruption overlying the CNV decreased by 4.2%. Mean area of fluorescein angiography leakage decreased by 6.3%. Both the area of outer retinal disruption measured with MinIP OCT and the area of leakage on fluorescein angiography typically exceeded the area of CNV on indocyanine green angiography at baseline and 1 year. Choroidal neovascularization treated with induction/pro re nata intravitreal ranibizumab for 1 year essentially remained static. Minimum intensity projection optical coherence tomography suggests that the area of outer retinal disruption overlying the CNV may be greater than the CNV itself and often correlates with the leakage area on fluorescein angiography. Additionally, there was minimal change in the area of outer retinal disruption on MinIP OCT even when fluid resolved. Measurements of the extent of CNV lesions based on indocyanine green angiography and MinIP OCT may provide useful outcome variables to help assess the CNV complex longitudinally and warrant further validation.

  14. POWER SPECTRAL DENSITY OF FLUCTUATIONS OF BULK AND THERMAL SPEEDS IN THE SOLAR WIND

    International Nuclear Information System (INIS)

    Šafránková, J.; Němeček, Z.; Němec, F.; Přech, L.; Chen, C. H. K.; Zastenker, G. N.

    2016-01-01

    This paper analyzes solar wind power spectra of bulk and thermal speed fluctuations that are computed with a time resolution of 32 ms in the frequency range of 0.001–2 Hz. The analysis uses measurements of the Bright Monitor of the Solar Wind on board the Spektr-R spacecraft that are limited to 570 km s 1 bulk speed. The statistics, based on more than 42,000 individual spectra, show that: (1) the spectra of bulk and thermal speeds can be fitted by two power-law segments; (2) despite their large variations, the parameters characterizing frequency spectrum fits computed on each particular time interval are very similar for both quantities; (3) the median slopes of the bulk and thermal speeds of the segment attributed to the MHD scale are 1.43 and 1.38, respectively, whereas they are 3.08 and 2.43 in the kinetic range; (4) the kinetic range slopes of bulk and thermal speed spectra become equal when either the ion density or magnetic field strength are high; (5) the break between MHD and kinetic scales seems to be controlled by the ion β parameter; (6) the best scaling parameter for bulk and thermal speed variations is a sum of the inertial length and proton thermal gyroradius; and (7) the above conclusions can be applied to the density variations if the background magnetic field is very low.

  15. POWER SPECTRAL DENSITY OF FLUCTUATIONS OF BULK AND THERMAL SPEEDS IN THE SOLAR WIND

    Energy Technology Data Exchange (ETDEWEB)

    Šafránková, J.; Němeček, Z.; Němec, F.; Přech, L. [Charles University, Faculty of Mathematics and Physics, V Holešovičkách 2, 180 00 Prague 8 (Czech Republic); Chen, C. H. K. [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom); Zastenker, G. N., E-mail: jana.safrankova@mff.cuni.cz [Space Research Institute of Russian Academy of Sciences, Moscow, Russia, Profsoyuznaya ul. 84/32, Moscow 117997 (Russian Federation)

    2016-07-10

    This paper analyzes solar wind power spectra of bulk and thermal speed fluctuations that are computed with a time resolution of 32 ms in the frequency range of 0.001–2 Hz. The analysis uses measurements of the Bright Monitor of the Solar Wind on board the Spektr-R spacecraft that are limited to 570 km s{sup 1} bulk speed. The statistics, based on more than 42,000 individual spectra, show that: (1) the spectra of bulk and thermal speeds can be fitted by two power-law segments; (2) despite their large variations, the parameters characterizing frequency spectrum fits computed on each particular time interval are very similar for both quantities; (3) the median slopes of the bulk and thermal speeds of the segment attributed to the MHD scale are 1.43 and 1.38, respectively, whereas they are 3.08 and 2.43 in the kinetic range; (4) the kinetic range slopes of bulk and thermal speed spectra become equal when either the ion density or magnetic field strength are high; (5) the break between MHD and kinetic scales seems to be controlled by the ion β parameter; (6) the best scaling parameter for bulk and thermal speed variations is a sum of the inertial length and proton thermal gyroradius; and (7) the above conclusions can be applied to the density variations if the background magnetic field is very low.

  16. Psychomotor and Motor Speed in Power Athletes Self-Administering Testosterone and Anabolic Steroids.

    Science.gov (United States)

    Era, Pertti; And Others

    1988-01-01

    Self-administered testosterone and anabolic steroids resulted in insignificant improvement in psychomotor and motor speed tests of power athletes. This study is part of a larger study on the effects of such drugs on endocrinology, metabolism and neuromuscular functions. Methodolgy and results are discussed. (Author/JL)

  17. Ensemble Nonlinear Autoregressive Exogenous Artificial Neural Networks for Short-Term Wind Speed and Power Forecasting.

    Science.gov (United States)

    Men, Zhongxian; Yee, Eugene; Lien, Fue-Sang; Yang, Zhiling; Liu, Yongqian

    2014-01-01

    Short-term wind speed and wind power forecasts (for a 72 h period) are obtained using a nonlinear autoregressive exogenous artificial neural network (ANN) methodology which incorporates either numerical weather prediction or high-resolution computational fluid dynamics wind field information as an exogenous input. An ensemble approach is used to combine the predictions from many candidate ANNs in order to provide improved forecasts for wind speed and power, along with the associated uncertainties in these forecasts. More specifically, the ensemble ANN is used to quantify the uncertainties arising from the network weight initialization and from the unknown structure of the ANN. All members forming the ensemble of neural networks were trained using an efficient particle swarm optimization algorithm. The results of the proposed methodology are validated using wind speed and wind power data obtained from an operational wind farm located in Northern China. The assessment demonstrates that this methodology for wind speed and power forecasting generally provides an improvement in predictive skills when compared to the practice of using an "optimal" weight vector from a single ANN while providing additional information in the form of prediction uncertainty bounds.

  18. Bicycle Design : A different approach to improving on the world human powered speed records

    NARCIS (Netherlands)

    Epema, H.K.; Van den Brand, S.; Gregoor, W.; Kooijman, J.D.G.; Pereboom, H.P.; Wielemaker, D.C.; Van der Zweep, C.J.

    2012-01-01

    The current International Human Powered Vehicle Association world records for faired bicycles stand at 133.284km/h for the 200m flying start speed record and 91.562 km for the hour record. Traditionally the recumbent bicycles that have been developed for breaking one of either of these records have

  19. Speed adaptation in a powered transtibial prosthesis controlled with a neuromuscular model.

    Science.gov (United States)

    Markowitz, Jared; Krishnaswamy, Pavitra; Eilenberg, Michael F; Endo, Ken; Barnhart, Chris; Herr, Hugh

    2011-05-27

    Control schemes for powered ankle-foot prostheses would benefit greatly from a means to make them inherently adaptive to different walking speeds. Towards this goal, one may attempt to emulate the intact human ankle, as it is capable of seamless adaptation. Human locomotion is governed by the interplay among legged dynamics, morphology and neural control including spinal reflexes. It has been suggested that reflexes contribute to the changes in ankle joint dynamics that correspond to walking at different speeds. Here, we use a data-driven muscle-tendon model that produces estimates of the activation, force, length and velocity of the major muscles spanning the ankle to derive local feedback loops that may be critical in the control of those muscles during walking. This purely reflexive approach ignores sources of non-reflexive neural drive and does not necessarily reflect the biological control scheme, yet can still closely reproduce the muscle dynamics estimated from biological data. The resulting neuromuscular model was applied to control a powered ankle-foot prosthesis and tested by an amputee walking at three speeds. The controller produced speed-adaptive behaviour; net ankle work increased with walking speed, highlighting the benefits of applying neuromuscular principles in the control of adaptive prosthetic limbs.

  20. POWER PERFOMANCE UNDER CONSTANT SPEED TEST WITH PALM OIL BIODIESEL AND ITS BLENDS WITH DIESEL

    Directory of Open Access Journals (Sweden)

    E. U. U. Ituen

    2010-06-01

    Full Text Available The torque and power performance tests were carried out with a single cylinder techno four-stroke diesel engine under constant speeds of 2000, 1500 and 1100 rpm. Five fuels, the Dura Palm Oil biodiesel/diesel blend at 10/90 vol/vol, B210 and the diesel or Automotive gas oil (ago, the reference fuel, were involved. Brake torque and brake power data were plotted against brake mean effective pressure (Bmep since the latter is independent of engine speed and size and it is an indication of how power and torque are obtained per litre of fuel. The curves for the torque versus Bmep for the five fuels merged into single straight line curve which extended to the origin and with a gradient of 0.0719 m3 for all the three speed tests of 2000, 1500 and 1100 rpm. Similarly, the power versus Bmep curves for the five fuels merged into one straight curve which also extended to the origin but with different gradients of 0.0151, 0.0113, 0.0083 for 2000, 1500 and 1100 rpm respectively. Therefore, the five fuels had similar torque and power performance characteristics in the engine. The straight line curve which can be extrapolated to any value can be used for the engine designs, that is determining vd from the relation, T=V/4 or Bp=VdN/2

  1. A Simple and Effective Approach for the Prediction of Turbine Power Production From Wind Speed Forecast

    Directory of Open Access Journals (Sweden)

    Marino Marrocu

    2017-11-01

    Full Text Available An accurate forecast of the power generated by a wind turbine is of paramount importance for its optimal exploitation. Several forecasting methods have been proposed either based on a physical modeling or using a statistical approach. All of them rely on the availability of high quality measures of local wind speed, corresponding generated power and on numerical weather forecasts. In this paper, a simple and effective wind power forecast technique, based on the probability distribution mapping of wind speed forecast and observed power data, is presented and it is applied to two turbines located on the island of Borkum (Germany in the North Sea. The wind speed forecast of the ECMWF model at 100 m from the ground is used as the prognostic meteorological parameter. Training procedures are based entirely on relatively short time series of power measurements. Results show that our approach has skills that are similar or better than those obtained using more standard methods when measured with mean absolute error.

  2. SYSTEM FOR AUTOMATIC SELECTION OF THE SPEED RATE OF ELECTRIC VEHICLES FOR REDUCING THE POWER CONSUMPTION

    Directory of Open Access Journals (Sweden)

    K. O. Soroka

    2017-06-01

    Full Text Available Purpose. The work is aimed to design a system for automatic selection of the optimal traffic modes and automatic monitoring of the electric energy consumption by electric transport. This automatic system should provide for the minimum energy expenses. Methodology. Current methodologies: 1 mathematical modeling of traffic modes of ground electric vehicles; 2 comparison of modelling results with the statistical monitoring; 3 system development for automatic choice of traffic modes of electric transport with minimal electrical energy consumptions taking into account the given route schedules and the limitations imposed by the general traffic rules. Findings. The authors obtained a mathematical dependency of the energy consumption by electric transport enterprises on the monthly averaged environment temperature was obtained. A system which allows for an automatic selection of the speed limit and provides automatic monitoring of the electrical energy consumption by electric vehicles was proposed in the form of local network, which works together with existing GPS system. Originality. A mathematical model for calculating the motion curves and energy consumption of electric vehicles has been developed. This model takes into account the characteristic values of the motor engine and the steering system, the change of the mass when loading or unloading passengers, the slopes and radii of the roads, the limitations given by the general traffic rules, and other factors. The dependency of the energy consumption on the averaged monthly environment temperature for public electric transport companies has been calculated. Practical value. The developed mathematical model simplifies the calculations of the traffic dynamics and energy consumption. It can be used for calculating the routing maps, for design and upgrade of the power networks, for development of the electricity saving measures. The system simplifies the work of the vehicle driver and allows reducing

  3. A novel technology for control of variable speed pumped storage power plant

    Institute of Scientific and Technical Information of China (English)

    Seyed Mohammad Hassan Hosseini; Mohammad Reza Semsar

    2016-01-01

    Variable speed pumped storage machines are used extensively in wind power plant and pumped storage power plant. This paper presents direct torque and flux control (DTFC) of a variable speed pumped storage power plant (VSPSP). By this method both torque and flux have been applied to control the VSPSP. The comparison between VSPSP’s control strategies is studied. At the first, a wind turbine with the capacity 2.2 kW and DTFC control strategies simulated then a 250 MW VSPSP is simulated with all of its parts (including electrical, mechanical, hydraulic and its control system) by MATLAB software. In all of simulations, both converters including two-level voltage source converter (2LVSC) and three-level voltage source converter (3LVSC) are applied. The results of applying 2LVSC and 3LVSC are the rapid dynamic responses with better efficiency, reducing the total harmonic distortion (THD) and ripple of rotor torque and flux.

  4. Variable-Speed Power-Turbine Research at Glenn Research Center

    Science.gov (United States)

    Welch, Gerard E.; McVetta, Ashlie B.; Stevens, Mark A.; Howard, Samuel A.; Giel, Paul W.; Ameri, Ali, A.; To, Waiming; Skoch, Gary J.; Thurman, Douglas R.

    2012-01-01

    The main rotors of the NASA Large Civil Tilt-Rotor (LCTR) notional vehicle operate over a wide speed-range, from 100 percent at takeoff to 54 percent at cruise. The variable-speed power turbine (VSPT) offers one approach by which to effect this speed variation. VSPT aerodynamics challenges include high work factors at cruise, wide (40 to 60 ) incidence-angle variations in blade and vane rows over the speed range, and operation at low Reynolds numbers. Rotordynamics challenges include potential responsiveness to shaft modes within the 50 percent VSPT speed-range. A research effort underway at NASA Glenn Research Center, intended to address these key aerodynamic and rotordynamic challenges, is described. Conceptual design and 3-D multistage RANS and URANS analyses, conducted internally and under contract, provide expected VSPT sizing, stage-count, performance and operability information, and maps for system studies. Initial steps toward experimental testing of incidence-tolerant blading in a transonic linear cascade are described, and progress toward development/improvement of a simulation capability for multistage turbines with low Reynolds number transitional flow is summarized. Preliminary rotordynamics analyses indicate that viable concept engines with 50 percent VSPT shaft-speed range. Assessments of potential paths toward VSPT component-level testing are summarized.

  5. High-speed BWR power plant simulations on the special-purpose peripheral processor AD10

    International Nuclear Information System (INIS)

    Wulff, W.; Cheng, H.S.; Lekach, S.V.; Mallen, A.N.

    1985-01-01

    A newly developed technique is described for fast, on-line simulations of normal and accidental transients in nuclear power plants. The technique is based on the utilization of the special-purpose peripheral processor AD10, which is specifically designed for high-speed systems simulations through integration of large systems of nonlinear ordinary differential equations. The Peach Bottom-II Boiling Water Reactor power plant has been simulated and results are presented. It is shown that the new technique not only advances safety analyses but also supports plant monitoring, failure diagnosis and accident mitigation, as well as the training of nuclear power plant operators. (author)

  6. Understanding mismatches in body size, speed and power among adolescent rugby union players.

    Science.gov (United States)

    Krause, Lyndon M; Naughton, Geraldine A; Denny, Greg; Patton, Declan; Hartwig, Tim; Gabbett, Tim J

    2015-05-01

    With adolescent sport increasingly challenged by mismatches in size, new strategies are important to maximize participation. The objectives were to (1) improve the understanding of mismatches in physical size, speed and power in adolescent rugby union players, (2) explore associations between size and performance with demographic, playing-history, and injury profiles, and (3) explore the applicability of existing criteria for age/body mass-based dispensation (playing-down) strategies. Cross-sectional study. Four hundred and eighty-five male community rugby union players were recruited from three Australian states selected to represent community-based U12, U13, U14 and U15 players. Body mass, stature, speed (10, 30, and 40 m sprints) and lower-leg power (relative peak power and relative peak force) were measured. Independent student t-tests, linear regressions and Chi square analyses were undertaken. Mean values in age groups for size, speed and power masked considerable overlap in the ranges within specific age groups of adolescent rugby players. Only a small proportion of players (approximately 5%) shared the highest and lowest tertiles for speed, relative peak power and body mass. Physical size was not related to injury. The mean body mass of current community rugby union players was above the 75th percentile on normative growth-charts. The notion that bigger, faster, and more powerful characteristics occur simultaneously in adolescent rugby players was not supported in the present study. Current practices in body mass-based criteria for playing down an age group lack a sufficient evidence for decision-making. Dispensation solely based on body mass may not address mismatch in junior rugby union. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  7. Modeling and numerical techniques for high-speed digital simulation of nuclear power plants

    International Nuclear Information System (INIS)

    Wulff, W.; Cheng, H.S.; Mallen, A.N.

    1987-01-01

    Conventional computing methods are contrasted with newly developed high-speed and low-cost computing techniques for simulating normal and accidental transients in nuclear power plants. Six principles are formulated for cost-effective high-fidelity simulation with emphasis on modeling of transient two-phase flow coolant dynamics in nuclear reactors. Available computing architectures are characterized. It is shown that the combination of the newly developed modeling and computing principles with the use of existing special-purpose peripheral processors is capable of achieving low-cost and high-speed simulation with high-fidelity and outstanding user convenience, suitable for detailed reactor plant response analyses

  8. System design of the traction power supply for the high-speed line Beijing - Tianjin

    Energy Technology Data Exchange (ETDEWEB)

    Altmann, Martin; Fischer, Andreas; Tornow, Torsten [Siemens AG, Erlangen (Germany)

    2011-11-15

    The high-speed line Beijing - Tianjin connecting the Capital Beijing with the harbour city Tianjin is the first high-speed line in China dedicated only to passenger traffic and is operated at 300 km/h. The commercial service started in due time for the Olympic games in 2008. For the system design and a reliable traction power supply the simulation software Sitras {sup registered} Sidytrac was used. The program incorporates all modules necessary for the overall system design and relating detailed investigations. Measurements during system integration test validated the simulation results. (orig.)

  9. Analytical and Algorithmic Approaches to Determine the Number of Sensor Nodes for Minimum Power Consumption in LWSNs

    Directory of Open Access Journals (Sweden)

    Ali Soner Kilinc

    2017-08-01

    Full Text Available A Linear Wireless Sensor Network (LWSN is a kind of wireless sensor network where the nodes are deployed in a line. Since the sensor nodes are energy restricted, energy efficiency becomes one of the most significant design issues for LWSNs as well as wireless sensor networks. With the proper deployment, the power consumption could be minimized by adjusting the distance between the sensor nodes which is known as hop length. In this paper, analytical and algorithmic approaches are presented to determine the number of hops and sensor nodes for minimum power consumption in a linear wireless sensor network including equidistantly placed sensor nodes.

  10. Relationship of the Functional Movement Screen In-Line Lunge to Power, Speed, and Balance Measures

    Science.gov (United States)

    Hartigan, Erin H.; Lawrence, Michael; Bisson, Brian M.; Torgerson, Erik; Knight, Ryan C.

    2014-01-01

    Background: The in-line lunge of the Functional Movement Screen (FMS) evaluates lateral stability, balance, and movement asymmetries. Athletes who score poorly on the in-line lunge should avoid activities requiring power or speed until scores are improved, yet relationships between the in-line lunge scores and other measures of balance, power, and speed are unknown. Hypothesis: (1) Lunge scores will correlate with center of pressure (COP), maximum jump height (MJH), and 36.6-meter sprint time and (2) there will be no differences between limbs on lunge scores, MJH, or COP. Study Design: Descriptive laboratory study. Level of Evidence: Level 3. Methods: Thirty-seven healthy, active participants completed the first 3 tasks of the FMS (eg, deep squat, hurdle step, in-line lunge), unilateral drop jumps, and 36.6-meter sprints. A 3-dimensional motion analysis system captured MJH. Force platforms measured COP excursion. A laser timing system measured 36.6-m sprint time. Statistical analyses were used to determine whether a relationship existed between lunge scores and COP, MJH, and 36.6-m speed (Spearman rho tests) and whether differences existed between limbs in lunge scores (Wilcoxon signed-rank test), MJH, and COP (paired t tests). Results: Lunge scores were not significantly correlated with COP, MJH, or 36.6-m sprint time. Lunge scores, COP excursion, and MJH were not statistically different between limbs. Conclusion: Performance on the FMS in-line lunge was not related to balance, power, or speed. Healthy participants were symmetrical in lunging measures and MJH. Clinical Relevance: Scores on the FMS in-line lunge should not be attributed to power, speed, or balance performance without further examination. However, assessing limb symmetry appears to be clinically relevant. PMID:24790688

  11. Relationship of the functional movement screen in-line lunge to power, speed, and balance measures.

    Science.gov (United States)

    Hartigan, Erin H; Lawrence, Michael; Bisson, Brian M; Torgerson, Erik; Knight, Ryan C

    2014-05-01

    The in-line lunge of the Functional Movement Screen (FMS) evaluates lateral stability, balance, and movement asymmetries. Athletes who score poorly on the in-line lunge should avoid activities requiring power or speed until scores are improved, yet relationships between the in-line lunge scores and other measures of balance, power, and speed are unknown. (1) Lunge scores will correlate with center of pressure (COP), maximum jump height (MJH), and 36.6-meter sprint time and (2) there will be no differences between limbs on lunge scores, MJH, or COP. Descriptive laboratory study. Level 3. Thirty-seven healthy, active participants completed the first 3 tasks of the FMS (eg, deep squat, hurdle step, in-line lunge), unilateral drop jumps, and 36.6-meter sprints. A 3-dimensional motion analysis system captured MJH. Force platforms measured COP excursion. A laser timing system measured 36.6-m sprint time. Statistical analyses were used to determine whether a relationship existed between lunge scores and COP, MJH, and 36.6-m speed (Spearman rho tests) and whether differences existed between limbs in lunge scores (Wilcoxon signed-rank test), MJH, and COP (paired t tests). Lunge scores were not significantly correlated with COP, MJH, or 36.6-m sprint time. Lunge scores, COP excursion, and MJH were not statistically different between limbs. Performance on the FMS in-line lunge was not related to balance, power, or speed. Healthy participants were symmetrical in lunging measures and MJH. Scores on the FMS in-line lunge should not be attributed to power, speed, or balance performance without further examination. However, assessing limb symmetry appears to be clinically relevant.

  12. On the Profitability of Variable Speed Pump-Storage-Power in Frequency Restoration Reserve

    Science.gov (United States)

    Filipe, Jorge; Bessa, Ricardo; Moreira, Carlos; Silva, Bernardo

    2017-04-01

    The increase penetration of renewable energy sources (RES) into the European power system has introduced a significant amount of variability and uncertainty in the generation profiles raising the needs for ancillary services as well as other tools like demand response, improved generation forecasting techniques and changes to the market design. While RES is able to replace energy produced by the traditional centralized generation, it cannot displace its capacity in terms of ancillary services provided. Therefore, centralized generation capacity must be retained to perform this function leading to over-capacity issues and underutilisation of the assets. Large-scale reversible hydro power plants represent the majority of the storage solution installed in the power system. This technology comes with high investments costs, hence the constant search for methods to increase and diversify the sources of revenue. Traditional fixed speed pump storage units typically operate in the day-ahead market to perform price arbitrage and, in some specific cases, provide downward replacement reserve (RR). Variable speed pump storage can not only participate in RR but also contribute to FRR, given their ability to control its operating point in pumping mode. This work does an extended analysis of a complete bidding strategy for Pumped Storage Power, enhancing the economic advantages of variable speed pump units in comparison with fixed ones.

  13. Correlation of Pc5 wave power inside and outside themagnetosphere during high speed streams

    Directory of Open Access Journals (Sweden)

    R. L. Kessel

    2004-01-01

    Full Text Available We show a clear correlation between the ULF wave power (Pc5 range inside and outside the Earth's magnetosphere during high speed streams in 1995. We trace fluctuations beginning 200RE upstream using Wind data, to fluctuations just upstream from Earth's bow shock and in the magnetosheath using Geotail data and compare to pulsations on the ground at the Kilpisjarvi ground station. With our 5-month data set we draw the following conclusions. ULF fluctuations in the Pc5 range are found in high speed streams; they are non-Alfvénic at the leading edge and Alfvénic in the central region. Compressional and Alfvénic fluctuations are modulated at the bow shock, some features of the waveforms are preserved in the magnetosheath, but overall turbulence and wave power is enhanced by about a factor of 10. Parallel (compressional and perpendicular (transverse power are at comparable levels in the solar wind and magnetosheath, both in the compression region and in the central region of high speed streams. Both the total parallel and perpendicular Pc5 power in the solar wind (and to a lesser extent in the magnetosheath correlate well with the total Pc5 power of the ground-based H-component magnetic field. ULF fluctuations in the magnetosheath during high speed streams are common at frequencies from 1–4mHz and can coincide with the cavity eigenfrequencies of 1.3, 1.9, 2.6, and 3.4mHz, though other discrete frequencies are also often seen.

    Key words. Interplanetary physics (MHD waves and turbulence – Magnetospheric physics (solar wind-magnetosphere interactions; MHD waves and instabilities

  14. An Adaptive Frequency Strategy for Variable Speed Wind Turbines: Application to High Wind Integration Into Power Systems

    Directory of Open Access Journals (Sweden)

    Ana Fernández-Guillamón

    2018-06-01

    Full Text Available This paper presents a new frequency controller for variable speed wind turbines connected to the grid under power imbalance conditions. It is based on the fast power reserve emulation technique, having two different operation modes: overproduction and recovery mode. In the first mode, the active power provided by wind turbines is set over the mechanical power, reducing their rotational speed. This overproduction power is estimated according to the frequency excursion. In the second mode, the active power is established under the mechanical power to recover the initial rotational speed through a smooth trajectory. The power system considered for simulation purposes includes thermal, hydro-power and wind-power plants. The controller proposed has been evaluated under different mix-generation scenarios implemented in Matlab/Simulink. Extensive results and comparison to previous proposals are also included in the paper.

  15. Latitude and Power Characteristics of Solar Activity at the End of the Maunder Minimum

    Science.gov (United States)

    Ivanov, V. G.; Miletsky, E. V.

    2017-12-01

    Two important sources of information about sunspots in the Maunder minimum are the Spörer catalog (Spörer, 1889) and observations of the Paris observatory (Ribes and Nesme-Ribes, 1993), which cover in total the last quarter of the 17th and the first two decades of the 18th century. These data, in particular, contain information about sunspot latitudes. As we showed in (Ivanov et al., 2011; Ivanov and Miletsky, 2016), dispersions of sunspot latitude distributions are tightly related to sunspot indices, and we can estimate the level of solar activity in the past using a method which is not based on direct calculation of sunspots and weakly affected by loss of observational data. The latitude distributions of sunspots in the time of transition from the Maunder minimum to the regular regime of solar activity proved to be wide enough. It gives evidences in favor of, first, not very low cycle no.-3 (1712-1723) with the Wolf number in maximum W = 100 ± 50, and, second, nonzero activity in the maximum of cycle no.-4 (1700-1711) W = 60 ± 45. Therefore, the latitude distributions in the end of the Maunder minimum are in better agreement with the traditional Wolf numbers and new revisited indices of activity SN and GN (Clette et al., 2014; Svalgaard and Schatten, 2016) than with the GSN (Hoyt and Schatten, 1998); the latter provide much lower level of activity in this epoch.

  16. Optimal wind energy penetration in power systems: An approach based on spatial distribution of wind speed

    International Nuclear Information System (INIS)

    Zolfaghari, Saeed; Riahy, Gholam H.; Abedi, Mehrdad; Golshannavaz, Sajjad

    2016-01-01

    Highlights: • Chronological wind speeds at distinct locations of the wind farm are not the same. • Spatial distribution of wind speed affects wind farm’s output power expectation. • Neglecting wind speed’s spatial doubt leads to mistake in wind energy penetration. • Scenario-based method can be used for effective wind capacity penetration level. - Abstract: Contributing in power system expansions, the present study establishes an efficient scheme for optimal integration of wind energy resources. The proposed approach highly concerns the spatial distribution of wind speed at different points of a wind farm. In mathematical statements, a suitable probability distribution function (PDF) is well-designed for representing such uncertainties. In such conditions, it is likely to have dissimilar output powers for individual and identical wind turbines. Thus, the overall aggregated PDF of a wind farm remarkably influences the critical parameters including the expected power and energy, capacity factor, and the reliability metrics such as loss of load expectation (LOLE) and expected energy not supplied (EENS). Furthermore, the proposed approach is deployed for optimal allocation of wind energy in bulk power systems. Hence, two typical test systems are numerically analyzed to interrogate the performance of the proposed approach. The conducted survey discloses an over/underestimation of harvestable wind energy in the case of overlooking spatial distributions. Thus, inaccurate amounts of wind farm’s capacity factor, output power, energy and reliability indices might be estimated. Meanwhile, the number of wind turbines may be misjudged to be installed. However, the proposed approach yields in a fair judgment regarding the overall performance of the wind farm. Consequently, a reliable penetration level of wind energy to the power system is assured. Extra discussions are provided to deeply assess the promising merits of the founded approach.

  17. Upper body strength and power are associated with shot speed in men's ice hockey

    Directory of Open Access Journals (Sweden)

    Juraj Bežák

    2017-06-01

    Full Text Available Background: Recent studies that addressed shot speed in ice hockey have focused on the relationship between shot speed and variables such as a player's skills or hockey stick construction and its properties. There has been a lack of evidence that considers the relationship between shot speed and player strength, particularly in players at the same skill level. Objective: The aim of this study was to identify the relationship between maximal puck velocity of two shot types (the wrist shot and the slap shot and players' upper body strength and power. Methods: Twenty male professional and semi-professional ice hockey players (mean age 23.3 ± 2.4 years participated in this study. The puck velocity was measured in five trials of the wrist shot and five trials of the slap shot performed by every subject. All of the shots were performed on ice in a stationary position 11.6 meters in front of an electronic device that measures the speed of the puck. The selected strength and power variables were: muscle power in concentric contraction in the countermovement bench press with 40 kg and 50 kg measured with the FiTRODyne Premium device; bench press one-repetition maximum; and grip strength measured by digital hand dynamometer. Results: The correlations between strength/power variables and the puck velocity in the wrist shot and the slap shot ranged between .29-.72 and .16-.62, respectively. Puck velocities produced by wrist shots showed significant correlations with bench press muscle power with 40 kg (p = .004 and 50 kg (p < .001; and one-repetition maximum in bench press (p = .004. The slap shot puck velocity was significantly associated with bench press muscle power with 40 kg (p = .014 and 50 kg (p = .004. Conclusions: This study provides evidence that there are significant associations between shot speed and upper body strength and power.

  18. Robust control of speed and temperature in a power plant gas turbine.

    Science.gov (United States)

    Najimi, Ebrahim; Ramezani, Mohammad Hossein

    2012-03-01

    In this paper, an H(∞) robust controller has been designed for an identified model of MONTAZER GHAEM power plant gas turbine (GE9001E). In design phase, a linear model (ARX model) which is obtained using real data has been applied. Since the turbine has been used in a combined cycle power plant, its speed and also the exhaust gas temperature should be adjusted simultaneously by controlling fuel signals and compressor inlet guide vane (IGV) position. Considering the limitations on the system inputs, the aim of the control is to maintain the turbine speed and the exhaust gas temperature within desired interval under uncertainties and load demand disturbances. Simulation results of applying the proposed robust controller on the nonlinear model of the system (NARX model), fairly fulfilled the predefined aims. Simulations also show the improvement in the performance compared to MPC and PID controllers for the same conditions. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  19. Control of cooling of an oil-immersed power transformer by varying speed of fans

    OpenAIRE

    Đorđević, Nikola Z.; Žakula, Dane M.; Jevtić, Milica M.; Tomašević, Radojica Ž.; Radaković, Zoran R.

    2016-01-01

    The paper presents a prototype system for speed control of cooling fans for a small oil-immersed 6.6 kVA transformer, implemented on a standard PLC. Generally, the potential for optimization of the cooling process depends on the accessible cooling modes and construction of the transformer; basically the aim of the cooling system control is reduction in power consumption of the fans / pumps and keeping the top-oil temperature at constant value (to reduce transformer 'breathing' and infiltratio...

  20. Compact, Low-Power, and High-Speed Graphene-Based Integrated Photonic Modulator Technology

    Science.gov (United States)

    2017-11-02

    Compact, Low-Power, and High-Speed Graphene- Based Integrated Photonic Modulator Technology The views, opinions and/or findings contained in this...Graphene-Based Integrated Photonic Modulator Technology Report Term: 0-Other Email: sorger@gwu.edu Distribution Statement: 1-Approved for public release...which is an all-time record at Georgia Tech. Protocol Activity Status: Technology Transfer: Nothing to Report PARTICIPANTS: Person Months Worked

  1. PERFORMANCE OF DIFFERENT CMOS LOGIC STYLES FOR LOW POWER AND HIGH SPEED

    OpenAIRE

    Sreenivasa Rao.Ijjada; Ayyanna.G; G.Sekhar Reddy; Dr.V.Malleswara Rao

    2011-01-01

    Designing high-speed low-power circuits with CMOS technology has been a major research problem for many years. Several logic families have been proposed and used to improve circuit performance beyond that of conventional static CMOS family. Fast circuit families are becoming attractive in deep sub micron technologies since the performance benefits obtained from process scaling are decreasing as feature size decreases. This paper presents CMOS differential circuit families such as Dual rail do...

  2. DEVELOPMENT AND INFLUENCE OF SPEED POWER ON RESULTS PROGRESSION OF LOW VISION JAVELIN THROWERS

    Directory of Open Access Journals (Sweden)

    Milan Matić

    2013-07-01

    Full Text Available Power is a motor skill important for low vision javelin throwers. The motor skill development (power, speed, endurance etc. linked to the fact that javelin is the lightest throwing device, we come to conclusion that the result in this discipline depends much more on the speed and flexibility than on the power. Nevertheless, development of speed power significantly influences the acquiring of good results in above mentioned discipline. While working with low vision sportsmen the attention should be focused on possible limitations in training of power that could be determined by some kind of illness or injury primarly caused the low vision. Experimental method od survey based on one sample was applied (case study. Equipment used in the experiments were adjusted to the needs, age and level of condition of examinee- Grlica Miloš (current European Record Breaker, 3rd on the World’s Championship 2012 in New Zealand, discipline of javlin throwing, category F12. The survey consisted of two-months cycle in the period from 01/04/2012 until 01/06/2012 as a part of preparation for Paralympic Games in London 2012. Measured variables include: 5kg ball throwing in front and above, standing long jump, 4kg ball throwing exercise aut. Based on the applied tests a conclusion can be made that the impact of force on acquiring better results, in this discipline, is very strong. Regardless the acquired results, in our opinion too big and too fast improvement in this area of physical preparation can be contraproductive due to the occurence of inadequate movements in joints which are esential for the discipline. Power development is definitely crucial segment in modeling of training process for javelin throwers. There are many surveys and articles about this topic but very little focusing on disabled people. Future work should examine special characteristics and differences regarding this population.

  3. Gender-specific influences of balance, speed, and power on agility performance.

    Science.gov (United States)

    Sekulic, Damir; Spasic, Miodrag; Mirkov, Dragan; Cavar, Mile; Sattler, Tine

    2013-03-01

    The quick change of direction (i.e., agility) is an important athletic ability in numerous sports. Because of the diverse and therefore hardly predictable manifestations of agility in sports, studies noted that the improvement in speed, power, and balance should result in an improvement of agility. However, there is evident lack of data regarding the influence of potential predictors on different agility manifestations. The aim of this study was to determine the gender-specific influence of speed, power, and balance on different agility tests. A total of 32 college-aged male athletes and 31 college-aged female athletes (age 20.02 ± 1.89 years) participated in this study. The subjects were mostly involved in team sports (soccer, team handball, basketball, and volleyball; 80% of men, and 75% of women), martial arts, gymnastics, and dance. Anthropometric variables consisted of body height, body weight, and the body mass index. Five agility tests were used: a t-test (T-TEST), zig-zag test, 20-yard shuttle test, agility test with a 180-degree turn, and forward-backward running agility test (FWDBWD). Other tests included 1 jumping ability power test (squat jump, SQJ), 2 balance tests to determine the overall stability index and an overall limit of stability score (both measured by Biodex Balance System), and 2 running speed tests using a straight sprint for 10 and 20 m (S10 and S20, respectively). A reliability analysis showed that all the agility tests were reliable. Multiple regression and correlation analysis found speed and power (among women), and balance (among men), as most significant predictors of agility. The highest Pearson's correlation in both genders is found between the results of the FWDBWD and S10M tests (0.77 and 0.81 for men and women, respectively; p Power, measured using the SQJ, is significantly (p balance measures were significantly related to the agility performance for men but not for women. In addition to demonstrating a known relationship

  4. Speed-dependent emission of air pollutants from gasoline-powered passenger cars.

    Science.gov (United States)

    Jung, Sungwoon; Lee, Meehye; Kim, Jongchoon; Lyu, Youngsook; Park, Junhong

    2011-01-01

    In Korea emissions from motor vehicles are a major source of air pollution in metropolitan cities, and in Seoul a large proportion of the vehicle fleet is made up of gasoline-powered passenger cars. The carbon monoxide (CO), hydrocarbons (HC), oxides of nitrogen (NOx) and carbon dioxide (CO2) contained in the exhaust emissions from 76 gasoline-powered passenger cars equipped with three-way catalysts has been assessed by vehicle speed, vehicle mileage and model year. The results show that CO, HC, NOx and CO2 emissions remained almost unchanged at higher speeds but decreased rapidly at lower speeds. While a reduction in CO, HC and NOx emissions was noticeable in vehicles of recent manufacture and lower mileage, CO2 emissions were found to be insensitive to vehicle mileage, but strongly dependent on gross vehicle weight. Lower emissions from more recent gasoline-powered vehicles arose mainly from improvements in three-way catalytic converter technology following strengthened emission regulations. The correlation between CO2 emission and fuel consumption has been investigated with a view to establishing national CO2 emission standards for Korea.

  5. Effects of High Intensity Interval Training on Increasing Explosive Power, Speed, and Agility

    Science.gov (United States)

    Fajrin, F.; Kusnanik, N. W.; Wijono

    2018-01-01

    High Intensity Interval Training (HIIT) is a type of exercise that combines high-intensity exercise and low intensity exercise in a certain time interval. This type of training is very effective and efficient to improve the physical components. The process of improving athletes achievement related to how the process of improving the physical components, so the selection of a good practice method will be very helpful. This study aims to analyze how is the effects of HIIT on increasing explosive power, speed, and agility. This type of research is quantitative with quasi-experimental methods. The design of this study used the Matching-Only Design, with data analysis using the t-test (paired sample t-test). After being given the treatment for six weeks, the results showed there are significant increasing in explosive power, speed, and agility. HIIT in this study used a form of exercise plyometric as high-intensity exercise and jogging as mild or moderate intensity exercise. Increase was due to the improvement of neuromuscular characteristics that affect the increase in muscle strength and performance. From the data analysis, researchers concluded that, Exercises of High Intensity Interval Training significantly effect on the increase in Power Limbs, speed, and agility.

  6. The Design of a High Speed Low Power Phase Locked Loop

    CERN Document Server

    Liu, Tiankuan; Hou, Suen; Liang, Zhihua; Liu, Chonghan; Su, Da-Shung; Teng, Ping-Kun; Xiang, Annie C; Ye, Jingbo

    2009-01-01

    The upgrade of the ATLAS Liquid Argon Calorimeter readout system calls for the development of radiation tolerant, high speed and low power serializer ASIC. We have designed a phase locked loop using a commercial 0.25-μm Silicon-on- Sapphire (SoS) CMOS technology. Post-layout simulation indicates that tuning range is 3.79 – 5.01 GHz and power consumption is 104 mW. The PLL has been submitted for fabrication. The design and simulation results are presented.

  7. Space-time wind speed forecasting for improved power system dispatch

    KAUST Repository

    Zhu, Xinxin

    2014-02-27

    To support large-scale integration of wind power into electric energy systems, state-of-the-art wind speed forecasting methods should be able to provide accurate and adequate information to enable efficient, reliable, and cost-effective scheduling of wind power. Here, we incorporate space-time wind forecasts into electric power system scheduling. First, we propose a modified regime-switching, space-time wind speed forecasting model that allows the forecast regimes to vary with the dominant wind direction and with the seasons, hence avoiding a subjective choice of regimes. Then, results from the wind forecasts are incorporated into a power system economic dispatch model, the cost of which is used as a loss measure of the quality of the forecast models. This, in turn, leads to cost-effective scheduling of system-wide wind generation. Potential economic benefits arise from the system-wide generation of cost savings and from the ancillary service cost savings. We illustrate the economic benefits using a test system in the northwest region of the United States. Compared with persistence and autoregressive models, our model suggests that cost savings from integration of wind power could be on the scale of tens of millions of dollars annually in regions with high wind penetration, such as Texas and the Pacific northwest. © 2014 Sociedad de Estadística e Investigación Operativa.

  8. Analysis of power ramp rate and minimum power controllability of the MMS model for a plant dynamics analysis of a Prototype SFR

    International Nuclear Information System (INIS)

    Kim, Eui Kwang; Kim, Dehee; Joo, Hyungkook; Lee, Taeho

    2014-01-01

    A full plant dynamic model was developed for a prototype SFR using the Modular Modeling System (MMS). It includes the modeling of various subsystems such as the neutronics, primary and intermediate sodium systems of the NSSS, steam and water systems of the BOP, BOP controls, and the supervisory plant controls. The NSSS model is subdivided into component models, such as a Core, IHXs, Pumps, SGs, and the rest of the NSSS loop model. The BOP model is subdivided into a steam subsystem, feedwater subsystem, and preheater subsystem. Plant transient tests were performed to study the operational considerations. It includes varying the power ramp rate and studying the controllability at minimum power. Plant transient tests were performed to study operational considerations by using the MMS model for a prototype SFR. It includes varying the power ramp rate, studying the controllability at the minimum power set point. At a power ramp rate of higher than 2%, the steam temperature has a large deviation from the target. As the power set point decreases, the PHTS hot leg temperature and steam temperature tend to have higher deviations. After further refinement of the MMS model, it can be useful for developing the plant operation logics of the prototype SFR

  9. Using wind speed from a blade-mounted flow sensor for power and load assessment on modern wind turbines

    DEFF Research Database (Denmark)

    Pedersen, Mads M.; Larsen, Torben J.; Madsen, Helge Aa

    2017-01-01

    In this paper an alternative method to evaluate power performance and loads on wind turbines using a blade-mounted flow sensor is investigated. The hypothesis is that the wind speed measured at the blades has a high correlation with the power and loads such that a power or load assessment can...... be performed from a few hours or days of measurements. In the present study a blade-mounted five-hole pitot tube is used as the flow sensor as an alternative to the conventional approach, where the reference wind speed is either measured at a nearby met mast or on the nacelle using lidar technology or cup...... anemometers. From the flow sensor measurements, an accurate estimate of the wind speed at the rotor plane can be obtained. This wind speed is disturbed by the presence of the wind turbine, and it is therefore different from the free-flow wind speed. However, the recorded wind speed has a high correlation...

  10. Smoothing Control of Wind Farm Output by Using Kinetic Energy of Variable Speed Wind Power Generators

    Science.gov (United States)

    Sato, Daiki; Saitoh, Hiroumi

    This paper proposes a new control method for reducing fluctuation of power system frequency through smoothing active power output of wind farm. The proposal is based on the modulation of rotaional kinetic energy of variable speed wind power generators through power converters between permanent magnet synchronous generators (PMSG) and transmission lines. In this paper, the proposed control is called Fluctuation Absorption by Flywheel Characteristics control (FAFC). The FAFC can be easily implemented by adding wind farm output signal to Maximum Power Point Tracking control signal through a feedback control loop. In order to verify the effectiveness of the FAFC control, a simulation study was carried out. In the study, it was assumed that the wind farm consisting of PMSG type wind power generator and induction machine type wind power generaotors is connected with a power sysem. The results of the study show that the FAFC control is a useful method for reducing the impacts of wind farm output fluctuation on system frequency without additional devices such as secondary battery.

  11. Partial analysis of wind power limit for large disturbance using fixed speed wind turbine

    International Nuclear Information System (INIS)

    Santos Fuentefria, Ariel; Cairo Rodriguez, Daniel; Boza Valerino, Juan Gualberto

    2014-01-01

    The amount of wind power that allow an electric network without losing his stability as known as wind power limit. The wind power limit fundamentally depends on the wind turbine technology and the weakness level of the system. To know the system behaviors in dynamic performance having into account the worst disturbance is a very important matter, a short circuit in one of the most power transference line or the loss of a large generation unit was a large disturbance that can affect system stability. The wind power limit may change with the nature of the disturbance. To know the wind power limit considering this conditions allow use the wind at maximum level. In the present paper the behavior of fixed speed wind turbine for different fault types is analyzed, at those conditions, the wind power is increasing until the system become voltage unstable. For the analysis the IEEE 14 Bus Test Case is used. The Power System Analysis Toolbox (PSAT) package is used for the simulation. (author)

  12. Mildly disabled persons with multiple sclerosis use similar net joint power strategies as healthy controls when walking speed increases

    DEFF Research Database (Denmark)

    Brincks, John; Sørensen, Henrik; Dalgas, Ulrik

    2018-01-01

    flexors in mildly disabled persons with MS and healthy controls at different walking speeds. METHODS:Thirteen persons with MS and thirteen healthy controls participated and peak net joint power was calculated using 3D motion analysis. RESULTS:In general, no differences were found between speed......-matched healthy controls and persons with MS, but the fastest walking speed was significantly higher in healthy controls (2.42 m/s vs. 1.70 m/s). The net joint power increased in hip flexors, hip extensors, hip abductors, knee extensors and plantar flexors in both groups, when walking speed increased. Significant...... correlations between changes in walking speed and changes in net joint power of plantar flexors, hip extensors and hip flexors existed in healthy controls and persons with MS, and in net knee extensor absorption power of persons with MS only. CONCLUSION:In contrast to previous studies, these findings suggest...

  13. The effects of passive leg press training on jumping performance, speed, and muscle power.

    Science.gov (United States)

    Liu, Chiang; Chen, Chuan-Shou; Ho, Wei-Hua; Füle, Róbert János; Chung, Pao-Hung; Shiang, Tzyy-Yuang

    2013-06-01

    Passive leg press (PLP) training was developed based on the concepts of the stretch-shortening cycle (SSC) and the benefits of high muscle contraction velocity. Passive leg press training enables lower limb muscle groups to apply a maximum downward force against a platform moved up and down at high frequency by an electric motor. Thus, these muscle groups accomplished both concentric and eccentric isokinetic contractions in a passive, rapid, and repetitive manner. This study investigates the effects of 10 weeks of PLP training at high and low movement frequencies have on jumping performance, speed, and muscle power. The authors selected 30 college students who had not performed systematic resistance training in the previous 6 months, including traditional resistance training at a squat frequency of 0.5 Hz, PLP training at a low frequency of 0.5 Hz, and PLP training at a high frequency of 2.5 Hz, and randomly divided them into 3 groups (n = 10). The participants' vertical jump, drop jump, 30-m sprint performance, explosive force, and SSC efficiency were tested under the same experimental procedures at pre- and post-training. Results reveal that high-frequency PLP training significantly increased participants' vertical jump, drop jump, 30-m sprint performance, instantaneous force, peak power, and SSC efficiency (p training (p training significantly increased participants' vertical jump, 30-m sprint performance, instantaneous force, and peak power (p training only increased participants' 30-m sprint performance and peak power (p training at high movement frequency. A PLP training machine powered by an electrical motor enables muscles of the lower extremities to contract faster compared with voluntary contraction. Therefore, muscle training with high contraction velocity is one of the main methods of increasing muscle power. Passive leg press training is a unique method for enhancing jump performance, speed, and muscle power.

  14. Empirical investigation on using wind speed volatility to estimate the operation probability and power output of wind turbines

    International Nuclear Information System (INIS)

    Liu, Heping; Shi, Jing; Qu, Xiuli

    2013-01-01

    Highlights: ► Ten-minute wind speed and power generation data of an offshore wind turbine are used. ► An ARMA–GARCH-M model is built to simultaneously forecast wind speed mean and volatility. ► The operation probability and expected power output of the wind turbine are predicted. ► The integrated approach produces more accurate wind power forecasting than other conventional methods. - Abstract: In this paper, we introduce a quantitative methodology that performs the interval estimation of wind speed, calculates the operation probability of wind turbine, and forecasts the wind power output. The technological advantage of this methodology stems from the empowered capability of mean and volatility forecasting of wind speed. Based on the real wind speed and corresponding wind power output data from an offshore wind turbine, this methodology is applied to build an ARMA–GARCH-M model for wind speed forecasting, and then to compute the operation probability and the expected power output of the wind turbine. The results show that the developed methodology is effective, the obtained interval estimation of wind speed is reliable, and the forecasted operation probability and expected wind power output of the wind turbine are accurate

  15. Diagnosis of power generator sets by analyzing the crank shaft angular speed

    International Nuclear Information System (INIS)

    Desbazeille, M.

    2010-07-01

    This thesis deals with the diagnosis of a powerful 20-cylinder diesel engine which runs a generator set in a nuclear plant. The objective is to make a diagnosis by analyzing the crank shaft angular speed variations. Only combustion related faults are investigated. As the engine is very large, the first crank shaft natural modes are in the low frequencies. Torsional vibrations of the flexible crank shaft strongly complicate the analysis of the angular speed variations. Little attention has been paid to such large engines in the literature. First, a dynamical model with the assumption of a flexible crank shaft is established. The parameters of the model are optimized with the help of actual data. Then, an original automated diagnosis based on pattern recognition of the angular speed waveforms is proposed. Indeed, any faulty cylinder in combustion stroke will distort the angular speed waveform in a specific way which depends on its location with respect to nodes and anti-nodes of the modes. Reference patterns, representative of the engine conditions, are computed with the model constituting the main originality of this work. Promising results are obtained in operational phase. An experimental fuel leakage fault was correctly diagnosed, including detection and localization of the faulty cylinder and an indication of the severity of the fault. (author)

  16. A short-term ensemble wind speed forecasting system for wind power applications

    Science.gov (United States)

    Baidya Roy, S.; Traiteur, J. J.; Callicutt, D.; Smith, M.

    2011-12-01

    This study develops an adaptive, blended forecasting system to provide accurate wind speed forecasts 1 hour ahead of time for wind power applications. The system consists of an ensemble of 21 forecasts with different configurations of the Weather Research and Forecasting Single Column Model (WRFSCM) and a persistence model. The ensemble is calibrated against observations for a 2 month period (June-July, 2008) at a potential wind farm site in Illinois using the Bayesian Model Averaging (BMA) technique. The forecasting system is evaluated against observations for August 2008 at the same site. The calibrated ensemble forecasts significantly outperform the forecasts from the uncalibrated ensemble while significantly reducing forecast uncertainty under all environmental stability conditions. The system also generates significantly better forecasts than persistence, autoregressive (AR) and autoregressive moving average (ARMA) models during the morning transition and the diurnal convective regimes. This forecasting system is computationally more efficient than traditional numerical weather prediction models and can generate a calibrated forecast, including model runs and calibration, in approximately 1 minute. Currently, hour-ahead wind speed forecasts are almost exclusively produced using statistical models. However, numerical models have several distinct advantages over statistical models including the potential to provide turbulence forecasts. Hence, there is an urgent need to explore the role of numerical models in short-term wind speed forecasting. This work is a step in that direction and is likely to trigger a debate within the wind speed forecasting community.

  17. Performance Analysis of Modified Drain Gating Techniques for Low Power and High Speed Arithmetic Circuits

    Directory of Open Access Journals (Sweden)

    Shikha Panwar

    2014-01-01

    Full Text Available This paper presents several high performance and low power techniques for CMOS circuits. In these design methodologies, drain gating technique and its variations are modified by adding an additional NMOS sleep transistor at the output node which helps in faster discharge and thereby providing higher speed. In order to achieve high performance, the proposed design techniques trade power for performance in the delay critical sections of the circuit. Intensive simulations are performed using Cadence Virtuoso in a 45 nm standard CMOS technology at room temperature with supply voltage of 1.2 V. Comparative analysis of the present circuits with standard CMOS circuits shows smaller propagation delay and lesser power consumption.

  18. Reactive power generation in high speed induction machines by continuously occurring space-transients

    Science.gov (United States)

    Laithwaite, E. R.; Kuznetsov, S. B.

    1980-09-01

    A new technique of continuously generating reactive power from the stator of a brushless induction machine is conceived and tested on a 10-kw linear machine and on 35 and 150 rotary cage motors. An auxiliary magnetic wave traveling at rotor speed is artificially created by the space-transient attributable to the asymmetrical stator winding. At least two distinct windings of different pole-pitch must be incorporated. This rotor wave drifts in and out of phase repeatedly with the stator MMF wave proper and the resulting modulation of the airgap flux is used to generate reactive VA apart from that required for magnetization or leakage flux. The VAR generation effect increases with machine size, and leading power factor operation of the entire machine is viable for large industrial motors and power system induction generators.

  19. Analysis of Disturbance Source Inducing by The Variable Speed Wind Turbine System Forced Power Oscillations

    DEFF Research Database (Denmark)

    Tan, Jin; Hu, Weihao; Wang, Xiaoru

    2015-01-01

    The main focus of forced low frequency oscillations is to analyze the disturbance source and the origin of forced oscillations. In this paper, the origin of low-frequency periodical oscillations induced by wind turbines’ mechanical power is investigated and the mechanism is studied of fluctuating...... power transfer through permanent magnet generator wind turbine system. Considering the tower shadow and the wind shear effect, the mechanical and generator coupling model is developed by PSCAD. Simulation is done to analyze the impacts on output power of operation points and mechanical fluctuation...... components. It is shown that when the oscillation frequency of tower shadow coincides with the system natural frequency, it may cause forced oscillations, whereas, the wind shear and natural wind speed fluctuation are not likely to induce forced oscillations....

  20. Object-Oriented Economic Power Dispatch of Electrical Power System with minimum pollution using a Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    T. Bouktir

    2005-06-01

    Full Text Available This paper presents solution of optimal power flow (OPF problem of electrical power system via a genetic algorithm of real type. The objective is to minimize the total fuel cost of generation and environmental pollution caused by fossil based thermal generating units and also maintain an acceptable system performance in terms of limits on generator real and reactive power outputs, bus voltages, shunt capacitors/reactors, transformers tap-setting and power flow of transmission lines. CPU times can be reduced by decomposing the optimization constraints to active constraints that affect directly the cost function manipulated directly the GA, and passive constraints such as generator bus voltages and transformer tap setting maintained in their soft limits using a conventional constraint load flow. The algorithm was developed in an Object Oriented fashion, in the C++ programming language. This option satisfies the requirements of flexibility, extensibility, maintainability and data integrity. The economic power dispatch is applied to IEEE 30-bus model system (6-generator, 41-line and 20-load. The numerical results have demonstrate the effectiveness of the stochastic search algorithms because its can provide accurate dispatch solutions with reasonable time. Further analyses indicate that this method is effective for large-scale power systems.

  1. Power-Smoothing Scheme of a DFIG Using the Adaptive Gain Depending on the Rotor Speed and Frequency Deviation

    DEFF Research Database (Denmark)

    Lee, Hyewon; Hwang, Min; Muljadi, Eduard

    2017-01-01

    In an electric power grid that has a high penetration level of wind, the power fluctuation of a large-scale wind power plant (WPP) caused by varying wind speeds deteriorates the system frequency regulation. This paper proposes a power-smoothing scheme of a doubly-fed induction generator (DFIG...... demonstrate that the proposed scheme significantly lessens the output power fluctuation of a WPP under various scenarios by modifying the gain with the rotor speed and frequency deviation, and thereby it can regulate the frequency deviation within a narrow range.......) that significantly mitigates the system frequency fluctuation while preventing over-deceleration of the rotor speed. The proposed scheme employs an additional control loop relying on the system frequency deviation that operates in combination with the maximum power point tracking control loop. To improve the power...

  2. Control of cooling of an oil-immersed power transformer by varying speed of fans

    Directory of Open Access Journals (Sweden)

    Đorđević Nikola Z.

    2016-01-01

    Full Text Available The paper presents a prototype system for speed control of cooling fans for a small oil-immersed 6.6 kVA transformer, implemented on a standard PLC. Generally, the potential for optimization of the cooling process depends on the accessible cooling modes and construction of the transformer; basically the aim of the cooling system control is reduction in power consumption of the fans / pumps and keeping the top-oil temperature at constant value (to reduce transformer 'breathing' and infiltration of moisture. The following constraints should be taken into account: hot-spot temperature, its current value and the one which would appear for planned overloads must not exceed the allowed limit. Based on the results in steady state, the paper offers the quantitative determination of transformer thermal characteristics depending on the fan speed.

  3. A high speed low power low offset dynamic comparator used in SHA-less pipelined ADC

    Science.gov (United States)

    Shubin, Liu; Zhangming, Zhu; Yintang, Yang; Lianxi, Liu

    2014-05-01

    A novel fully differential high speed high resolution low offset CMOS dynamic comparator has been implemented in the SMIC 0.18 μm process used for a sample-and-hold amplifier (SHA)-less pipelined analog-to-digital converters (ADC). Based on the analysis and optimization between delay time and offset, an enhanced reset architecture with transmission gate was introduced to speed up the comparison and reset procedure. Four inputs with two cross coupled differential pairs, reconstituted bias circuit for tail current transistor and common centroid layouts make the comparator more robust against mismatch and process variations. The simulation results demonstrate that the proposed design achieves 1 mV sensitivity at 2.2 GHz sampling rate with a power consumption of 510 μW, while the mean offset voltage is equal to 10.244 mV.

  4. Relationship between strength, power, speed, and change of direction performance of female softball players.

    Science.gov (United States)

    Nimphius, Sophia; McGuigan, Michael R; Newton, Robert U

    2010-04-01

    The purpose of this study was to investigate (a) the cross-sectional relationship of strength, power, and performance variables in trained female athletes and (b) determine if the relationship between these variables changes over the course of a season. Ten female softball players (age = 18.1 +/- 1.6 years, height = 166.5 +/- 8.9 cm, and weight = 72.4 +/- 10.8 kg) from a state Australian Institute of Sport softball team were tested for maximal lower body strength (one repetition maximum [1RM]), peak force (PF), peak velocity (PV), and peak power (PP) during jump squats unloaded and loaded, unloaded countermovement vertical jump height (VJH) 1 base and 2 base sprint performance and change of direction performance on dominant and nondominant sides. The testing sessions occurred pre, mid, and post a 20-week training period. Relationship between body weight (BW), relative strength (1RM/BW), VJH, relative PP, relative PF, PV, speed, and change of direction variables were assessed by Pearson product-moment correlation coefficient at each testing session. Significant relationships were found across all time points with BW, speed, and change of direction measures (r = 0.70-0.93) and relative strength and measures of speed and change of direction ability (r = -0.73-0.85). There were no significant relationships between VJH and any measure of performance at any time point. In conclusion, BW and relative strength have strong to very strong correlations with speed and change of direction ability, and these correlations remain consistent over the course of the season. However, it seems as if many relationships vary with time, and their relationships should therefore be investigated longitudinally to better determine if these cross-sectional relationships truly reflect a deterministic relationship.

  5. Simple Exact Algorithm for Transistor Sizing of Low-Power High-Speed Arithmetic Circuits

    Directory of Open Access Journals (Sweden)

    Tooraj Nikoubin

    2010-01-01

    Full Text Available A new transistor sizing algorithm, SEA (Simple Exact Algorithm, for optimizing low-power and high-speed arithmetic integrated circuits is proposed. In comparison with other transistor sizing algorithms, simplicity, accuracy, independency of order and initial sizing factors of transistors, and flexibility in choosing the optimization parameters such as power consumption, delay, Power-Delay Product (PDP, chip area or the combination of them are considered as the advantages of this new algorithm. More exhaustive rules of grouping transistors are the main trait of our algorithm. Hence, the SEA algorithm dominates some major transistor sizing metrics such as optimization rate, simulation speed, and reliability. According to approximate comparison of the SEA algorithm with MDE and ADC for a number of conventional full adder circuits, delay and PDP have been improved 55.01% and 57.92% on an average, respectively. By comparing the SEA and Chang's algorithm, 25.64% improvement in PDP and 33.16% improvement in delay have been achieved. All the simulations have been performed with 0.13 m technology based on the BSIM3v3 model using HSpice simulator software.

  6. Fuzzy logic speed control for the engine of an air-powered vehicle

    Directory of Open Access Journals (Sweden)

    Qihui Yu

    2016-03-01

    Full Text Available To improve the condition of air and eliminate exhaust gas pollution, this article proposes a compressed air power system. Instead of an internal combustion engine, the automobile is equipped with a compressed air engine, which transforms the energy of compressed air into mechanical motion energy. A prototype was built, and the compressed air engine was tested on an experimental platform. The output torque and energy efficiency were obtained from experimental results. When the supply pressure was set at 2 MPa and the speed was 420 r min−1, the output torque, the output power, and the energy efficiency were 56 N m, 1.93 kW, and 25%, respectively. To improve the efficiency of the system, a fuzzy logic speed control strategy is proposed and simulated. The experimental study verified that the theoretical evaluation of the system was reasonable, and this research can be referred to as the design and control of air-powered vehicles.

  7. High performance integrated solar combined cycles with minimum modifications to the combined cycle power plant design

    International Nuclear Information System (INIS)

    Manente, Giovanni

    2016-01-01

    Highlights: • Off-design model of a 390 MW_e three pressure combined cycle developed and validated. • The off-design model is used to evaluate different hybridization schemes with solar. • Power boosting and fuel saving with different design modifications are considered. • Maximum solar share of total electricity is only 1% with the existing equipment. • The maximum incremental solar radiation-to-electrical efficiency approaches 29%. - Abstract: The integration of solar energy into natural gas combined cycles has been successfully demonstrated in several integrated solar combined cycles since the beginning of this decade in many countries. There are many motivations that drive investments on integrated solar combined cycles which are primarily the repowering of existing power plants, the compliance with more severe environmental laws on emissions and the mitigation of risks associated with large solar projects. Integrated solar combined cycles are usually developed as brownfield facilities by retrofitting existing natural gas combined cycles and keeping the existing equipment to minimize costs. In this work a detailed off-design model of a 390 MW_e three pressure level natural gas combined cycle is built to evaluate different integration schemes of solar energy which either keep the equipment of the combined cycle unchanged or include new equipment (steam turbine, heat recovery steam generator). Both power boosting and fuel saving operation strategies are analyzed in the search for the highest annual efficiency and solar share. Results show that the maximum incremental power output from solar at design solar irradiance is limited to 19 MW_e without modifications to the existing equipment. Higher values are attainable only including a larger steam turbine. High solar radiation-to-electrical efficiencies in the range 24–29% can be achieved in the integrated solar combined cycle depending on solar share and extension of tube banks in the heat recovery

  8. Role of parasitic capacitances in power MOSFET turn-on switching speed limits

    DEFF Research Database (Denmark)

    Cittanti, Davide; Iannuzzo, Francesco; Hoene, Eckart

    2017-01-01

    This paper describes the effect of MOSFET internal capacitances on the channel current during the turn-on switching transition: an intrinsic theoretical switching speed limit is found and detailed mathematically. The set of analytical equations is solved and the effect of the displacement currents...... is highlighted with ideal simulated waveforms. A laboratory experiment is thus performed, in order to prove the theoretical predictions: a 25 mΩ SiC CREE power MOSFET is turned on in a no-load condition (zero drain current), starting from different drain-source voltage values. Finally, a LTSpice equivalent...

  9. Assessment of Power Potential of Tidal Currents and Impacts of Power Extraction on Flow Speeds in Indonesia

    Science.gov (United States)

    Orhan, K.; Mayerle, R.

    2016-12-01

    A methodology comprising of the estimates of power yield, evaluation of the effects of power extraction on flow conditions, and near-field investigations to deliver wake characteritics, recovery and interactions is described and applied to several straits in Indonesia. Site selection is done with high-resolution, three-dimensional flow models providing sufficient spatiotemporal coverage. Much attention has been given to the meteorological forcing, and conditions at the open sea boundaries to adequately capture the density gradients and flow fields. Model verification using tidal records shows excellent agreement. Sites with adequate depth for the energy conversion using horizontal axis tidal turbines, average kinetic power density greater than 0.5 kW/m2, and surface area larger than 0.5km2 are defined as energy hotspots. Spatial variation of the average extractable electric power is determined, and annual tidal energy resource is estimated for the straits in question. The results showed that the potential for tidal power generation in Indonesia is likely to exceed previous predictions reaching around 4,800MW. To assess the impact of the devices, flexible mesh models with higher resolutions have been developed. Effects on flow conditions, and near-field turbine wakes are resolved in greater detail with triangular horizontal grids. The energy is assumed to be removed uniformly by sub-grid scale arrays of turbines, and calculations are made based on velocities at the hub heights of the devices. An additional drag force resulting in dissipation of the pre-existing kinetic power from %10 to %60 within a flow cross-section is introduced to capture the impacts. It was found that the effect of power extraction on water levels and flow speeds in adjacent areas is not significant. Results show the effectivess of the method to capture wake characteritics and recovery reasonably well with low computational cost.

  10. Minimum long-term cost solution for remote telecommunication stations on the basis of photovoltaic-based hybrid power systems

    International Nuclear Information System (INIS)

    Kaldellis, J.K.; Ninou, I.; Zafirakis, D.

    2011-01-01

    In the case of the telecommunication (T/C) services' expansion to rural and remote areas, the market generally responds with the minimum investments required. Considering the existing situation, cost-effective operation of the T/C infrastructure installed in these regions (i.e. remote T/C stations) becomes critical. However, since in most cases grid-connection is not feasible, the up-to-now electrification solution for remote T/C stations is based on the operation of costly, oil consuming and heavy polluting diesel engines. Instead, the use of photovoltaic (PV)-based hybrid power stations is currently examined, using as a case study a representative remote T/C station of the Greek territory. In this context, the present study is concentrated on the detailed cost-benefit analysis of the proposed solution. More precisely, the main part of the analysis is devoted to develop a complete electricity production cost model, accordingly applied for numerous oil consumption and service period scenarios. Note that in all cases examined, zero load rejections is a prerequisite while minimum long-term cost solutions designated are favorably compared with the diesel-only solution. Finally, a sensitivity analysis, demonstrating the impact of the main economic parameters on the energy production cost of optimum sized PV-diesel hybrid power stations, is also provided. - Research highlights: → Expansion of telecommunication (T/C) in remote areas is vital for their development. → Off-grid T/C stations employed in such areas operate on diesel engines. → The use of PV-diesel-battery hybrid power stations is currently examined. → A detailed long-term electricity production cost model is developed. → Cost-effectiveness of the proposed system is reflected for numerous configurations.

  11. Novel high efficient speed sensorless controller for maximum power extraction from wind energy conversion systems

    International Nuclear Information System (INIS)

    Fathabadi, Hassan

    2016-01-01

    Highlights: • Novel sensorless MPPT technique without drawbacks of other sensor/sensorless methods. • Tracking the actual MPP of WECSs, no tracking the MPP of their wind turbines. • Actually extracting the highest output power from WECSs. • Novel MPPT technique having the MPPT efficiency more than 98.5% for WECSs. • Novel MPPT technique having short convergence time for WECSs. - Abstract: In this study, a novel high accurate sensorless maximum power point tracking (MPPT) method is proposed. The technique tracks the actual maximum power point of a wind energy conversion system (WECS) at which maximum output power is extracted from the system, not the maximum power point of its wind turbine at which maximum mechanical power is obtained from the turbine, so it actually extracts the highest output power from the system. The technique only uses input voltage and current of the converter used in the system, and neither needs any speed sensors (anemometer and tachometer) nor has the drawbacks of other sensor/sensorless based MPPT methods. The technique has been implemented as a MPPT controller by constructing a WECS. Theoretical results, the technique performance, and its advantages are validated by presenting real experimental results. The real static-dynamic response of the MPPT controller is experimentally obtained that verifies the proposed MPPT technique high accurately extracts the highest instant power from wind energy conversion systems with the MPPT efficiency of more than 98.5% and a short convergence time that is only 25 s for the constructed system having a total inertia and friction coefficient of 3.93 kg m 2 and 0.014 N m s, respectively.

  12. Sliding mode direct power control of RSC for DFIGs driven by variable speed wind turbines

    Directory of Open Access Journals (Sweden)

    E.G. Shehata

    2015-12-01

    Full Text Available In spite of its several advantages, a classic direct power control (DPC of doubly fed induction generators (DFIGs driven by variable speed wind turbines has some drawbacks. In this paper, a simple and robust total sliding mode controller (TSMC is designed to improve the classical DPC performance without complicating the overall scheme. The TSMC is designed to regulate the DFIG stator active and reactive powers. Two integral switching functions are selected for describing the switching surfaces of the active and reactive powers. Reaching phase stability problem of the classical sliding mode controller is avoided in the proposed TSMC. Neither current control loops nor accurate values of machine parameters are required in the proposed scheme. In addition, axes transformation of the stator voltage and current are eliminated. The grid side converter is controlled based on DPC principle to regulate both DC-link voltage and total reactive power. The feasibility of the proposed DPC scheme is validated through simulation studies on a 1.5 MW wind power generation system. The performance of the proposed and conventional DPC schemes is compared under different operating conditions.

  13. High-speed extended-term time-domain simulation for online cascading analysis of power system

    Science.gov (United States)

    Fu, Chuan

    A high-speed extended-term (HSET) time domain simulator (TDS), intended to become a part of an energy management system (EMS), has been newly developed for use in online extended-term dynamic cascading analysis of power systems. HSET-TDS includes the following attributes for providing situational awareness of high-consequence events: (i) online analysis, including n-1 and n-k events, (ii) ability to simulate both fast and slow dynamics for 1-3 hours in advance, (iii) inclusion of rigorous protection-system modeling, (iv) intelligence for corrective action ID, storage, and fast retrieval, and (v) high-speed execution. Very fast on-line computational capability is the most desired attribute of this simulator. Based on the process of solving algebraic differential equations describing the dynamics of power system, HSET-TDS seeks to develop computational efficiency at each of the following hierarchical levels, (i) hardware, (ii) strategies, (iii) integration methods, (iv) nonlinear solvers, and (v) linear solver libraries. This thesis first describes the Hammer-Hollingsworth 4 (HH4) implicit integration method. Like the trapezoidal rule, HH4 is symmetrically A-Stable but it possesses greater high-order precision (h4 ) than the trapezoidal rule. Such precision enables larger integration steps and therefore improves simulation efficiency for variable step size implementations. This thesis provides the underlying theory on which we advocate use of HH4 over other numerical integration methods for power system time-domain simulation. Second, motivated by the need to perform high speed extended-term time domain simulation (HSET-TDS) for on-line purposes, this thesis presents principles for designing numerical solvers of differential algebraic systems associated with power system time-domain simulation, including DAE construction strategies (Direct Solution Method), integration methods(HH4), nonlinear solvers(Very Dishonest Newton), and linear solvers(SuperLU). We have

  14. Variable speed DFIG wind energy system for power generation and harmonic current mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Gaillard, A.; Saadate, S. [Groupe de Recherche en Electrotechnique et Electronique de Nancy, Nancy Universite - Universite Henri Poincare Nancy 1, BP239, 54506 Vandoeuvre les Nancy Cedex (France); Poure, P. [Laboratoire d' Instrumentation Electronique de Nancy, Nancy Universite - Universite Henri Poincare Nancy 1, BP239, 54506 Vandoeuvre les Nancy Cedex (France); Machmoum, M. [IREENA, 37 Boulevard de l' Universite, BP 406, 44602 Saint-Nazaire Cedex (France)

    2009-06-15

    This paper presents a novel approach for simultaneous power generation and harmonic current mitigation using variable speed WECS with DFIG. A new control strategy is proposed to upgrade the DFIG control to achieve simultaneously a green active and reactive power source with active filtering capability. To ensure high filtering performance, we studied an improved harmonic isolator in the time-domain, based on a new high selectivity filter developed in our laboratory. We examined two solutions for harmonic current mitigation: first, by compensating the whole harmonic component of the grid currents or second, by selective isolation of the predominant harmonic currents to ensure active filtering of the 5th and 7th harmonics. Simulation results for a 3 MW WECS with DFIG confirm the effectiveness and the performance of the two proposed approaches. (author)

  15. Power-Quality-Oriented Optimization in Multiple Three-Phase Adjustable Speed Drives

    DEFF Research Database (Denmark)

    Yang, Yongheng; Davari, Pooya; Blaabjerg, Frede

    2016-01-01

    As an almost standardized configuration, Diode Rectifiers (DRs) and Silicon-Controlled Rectifiers (SCRs) are commonly employed as the front-end topology in three-phase Adjustable Speed Drive (ASD) systems. Features of this ASD configuration include: structural and control simplicity, small volume......, low cost, and high reliability during operation. Yet, DRs and SCRs bring harmonic distortions in the mains and thus lowering the overall efficiency. Power quality standards/rules are thus released. For multiple ASD systems, certain harmonics of the total grid current can be mitigated by phase......-shifting the currents drawn by SCR-fed drives, and thus it is much flexible to reduce the Total Harmonic Distortion (THD) level in such applications. However, the effectiveness of this harmonic mitigation scheme for multiple ASD systems depends on: a) the number of parallel drives, b) the power levels, and c...

  16. A high speed, low power consumption LVDS interface for CMOS pixel sensors

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Zhan, E-mail: sz1134@163.com [Dalian University of Technology, No. 2 Linggong Road, 116024 Dalian (China); Tang, Zhenan, E-mail: tangza@dlut.edu.cn [Dalian University of Technology, No. 2 Linggong Road, 116024 Dalian (China); Tian, Yong [Dalian University of Technology, No. 2 Linggong Road, 116024 Dalian (China); Pham, Hung; Valin, Isabelle; Jaaskelainen, Kimmo [IPHC, 23 rue du Loess 67037 Strasbourg (France); CNRS, UMR7178, 67037 Strasbourg (France)

    2015-01-01

    The use of CMOS Pixel Sensors (CPSs) offers a promising approach to the design of vertex detectors in High Energy Physics (HEP) experiments. As the CPS equipping the upgraded Solenoidal Tracker at RHIC (STAR) pixel detector, ULTIMATE perfectly illustrates the potential of CPSs for HEP applications. However, further development of CPSs with respect to readout speed is required to fulfill the readout time requirement of the next generation HEP detectors, such as the upgrade of A Large Ion Collider Experiment (ALICE) Inner Tracking System (ITS), the International Linear Collider (ILC), and the Compressed Baryonic Matter (CBM) vertex detectors. One actual limitation of CPSs is related to the speed of the Low-Voltage Differential Signaling (LVDS) circuitry implementing the interface between the sensor and the Data Acquisition (DAQ) system. To improve the transmission rate while keeping the power consumption at a low level, a source termination technique and a special current comparator were adopted for the LVDS driver and receiver, respectively. Moreover, hardening techniques are used. The circuitry was designed and submitted for fabrication in a 0.18-µm CMOS Image Sensor (CIS) process at the end of 2011. The test results indicated that the LVDS driver and receiver can operate properly at the data rate of 1.2 Gb/s with power consumption of 19.6 mW.

  17. Strength, power, speed, and agility of women basketball players according to playing position.

    Science.gov (United States)

    Delextrat, Anne; Cohen, Daniel

    2009-10-01

    The aim of the present study was to investigate the effect of playing position on strength, power, speed, and agility performances of women basketball players. Thirty subjects playing at national level participated in this study. They were divided into 3 groups according to playing position: guards (positions 1 and 2), forwards (positions 3 and 4), and centers (position 5). Each subject performed 8 tests presented in a random order: The 30-second Wingate Anaerobic test (WAnT), isokinetic testing of the knee extensors, 2 types of jump tests, a 20-m sprint, the agility T-test, a suicide run, and a basketball chest pass. Statistical differences between playing positions were assessed using a 1-way analysis of variance (ANOVA) and Scheffe post hoc analyses. Results showed that guards performed significantly better than centers for the relative peak and mean power achieved during the WAnT (+13% and +16.9%, respectively), relative peak torque of knee extensors (+19.5%), single-leg jump (+21.8), suicide run (+7.5%), and agility T-test (+6.4%, p training must be undertaken according to playing position. The ability to perform the suicide run, the single-leg jump, and the different movements involved in the agility T-test must be developed in guards. In contrast, speed over short distances and strength development of lower body and upper body should be performed by all playing positions.

  18. A transmission power optimization with a minimum node degree for energy-efficient wireless sensor networks with full-reachability.

    Science.gov (United States)

    Chen, Yi-Ting; Horng, Mong-Fong; Lo, Chih-Cheng; Chu, Shu-Chuan; Pan, Jeng-Shyang; Liao, Bin-Yih

    2013-03-20

    Transmission power optimization is the most significant factor in prolonging the lifetime and maintaining the connection quality of wireless sensor networks. Un-optimized transmission power of nodes either interferes with or fails to link neighboring nodes. The optimization of transmission power depends on the expected node degree and node distribution. In this study, an optimization approach to an energy-efficient and full reachability wireless sensor network is proposed. In the proposed approach, an adjustment model of the transmission range with a minimum node degree is proposed that focuses on topology control and optimization of the transmission range according to node degree and node density. The model adjusts the tradeoff between energy efficiency and full reachability to obtain an ideal transmission range. In addition, connectivity and reachability are used as performance indices to evaluate the connection quality of a network. The two indices are compared to demonstrate the practicability of framework through simulation results. Furthermore, the relationship between the indices under the conditions of various node degrees is analyzed to generalize the characteristics of node densities. The research results on the reliability and feasibility of the proposed approach will benefit the future real deployments.

  19. A Transmission Power Optimization with a Minimum Node Degree for Energy-Efficient Wireless Sensor Networks with Full-Reachability

    Science.gov (United States)

    Chen, Yi-Ting; Horng, Mong-Fong; Lo, Chih-Cheng; Chu, Shu-Chuan; Pan, Jeng-Shyang; Liao, Bin-Yih

    2013-01-01

    Transmission power optimization is the most significant factor in prolonging the lifetime and maintaining the connection quality of wireless sensor networks. Un-optimized transmission power of nodes either interferes with or fails to link neighboring nodes. The optimization of transmission power depends on the expected node degree and node distribution. In this study, an optimization approach to an energy-efficient and full reachability wireless sensor network is proposed. In the proposed approach, an adjustment model of the transmission range with a minimum node degree is proposed that focuses on topology control and optimization of the transmission range according to node degree and node density. The model adjusts the tradeoff between energy efficiency and full reachability to obtain an ideal transmission range. In addition, connectivity and reachability are used as performance indices to evaluate the connection quality of a network. The two indices are compared to demonstrate the practicability of framework through simulation results. Furthermore, the relationship between the indices under the conditions of various node degrees is analyzed to generalize the characteristics of node densities. The research results on the reliability and feasibility of the proposed approach will benefit the future real deployments. PMID:23519351

  20. Coordinated frequency control from offshore wind power plants connected to multi terminal DC system considering wind speed variation

    DEFF Research Database (Denmark)

    Sakamuri, Jayachandra N.; Altin, Müfit; Hansen, Anca Daniela

    2017-01-01

    A coordinated fast primary frequency control scheme from offshore wind power plants (OWPPs) integrated to a three terminal high voltage DC (HVDC) system is proposed in this study. The impact of wind speed variation on the OWPP active power output and thus on the AC grid frequency and DC grid...... the active power support from OWPP with a ramp rate limiter and (iii) An alternative method for the wind turbine overloading considering rotor speed. The effectiveness of the proposed control scheme is demonstrated on a wind power plant integrated into a three terminal HVDC system developed in DIg......SILIENT PowerFactory. The results show that the proposed coordinated frequency control method performs effectively at different wind speeds and minimises the secondary effects on frequency and DC voltage....

  1. Effects of Unloaded vs. Loaded Plyometrics on Speed and Power Performance of Elite Young Soccer Players

    Directory of Open Access Journals (Sweden)

    Ronaldo Kobal

    2017-09-01

    Full Text Available The purpose of this study was to investigate the effects of loaded and unloaded plyometric training strategies on speed and power performance of elite young soccer players. Twenty-three under-17 male soccer players (age: 15.9 ± 1.2 years, height: 178.3 ± 8.1 cm, body-mass (BM: 68.1 ± 9.3 kg from the same club took part in this study. The athletes were pair-matched in two training groups: loaded vertical and horizontal jumps using an haltere type handheld with a load of 8% of the athletes' body mass (LJ; n = 12 and unloaded vertical and horizontal plyometrics (UJ; n = 11. Sprinting speeds at 5-, 10-, and 20-m, mean propulsive power (MPP relative to the players' BM in the jump squat exercise, and performance in the squat jump (SJ and countermovement jump (CMJ were assessed pre- and post-training period. During the experimental period, soccer players performed 12 plyometric training sessions across a 6-week preseason period. Magnitude based inferences and standardized differences were used for statistical analysis. A very likely increase in the vertical jumps was observed for the LJ group (99/01/00 and 98/02/00 for SJ and CMJ, respectively. In the UJ group a likely increase was observed for both vertical jumps (83/16/01 and 90/10/00, for SJ and CMJ, respectively. An almost certainly decrease in the sprinting velocities along the 20-m course were found in the LJ group (00/00/100 for all split distances tested. Meanwhile, in the UJ likely to very likely decreases were observed for all sprinting velocities tested (03/18/79, 01/13/86, and 00/04/96, for velocities in 5-, 10-, and 20-m, respectively. No meaningful differences were observed for the MPP in either training group (11/85/04 and 37/55/08 for LJ and UJ, respectively. In summary, under-17 professional soccer players increased jumping ability after a 6-week preseason training program, using loaded or unloaded jumps. Despite these positive adaptations, both plyometric strategies failed to

  2. Simulation and study of power quality issues in a fixed speed wind farm substation.

    Science.gov (United States)

    Magesh, T; Chellamuthu, C

    2015-01-01

    Power quality issues associated with the fixed speed wind farm substation located at Coimbatore district are investigated as the wind generators are tripping frequently. The investigations are carried out using two power quality analyzers, Fluke 435 and Dranetz PX5.8, with one of them connected at group control breaker of the 110 kV feeder and the other at the selected 0.69 kV generator busbar during the period of maximum power generation. From the analysis of the recorded data it is found that sag, swell, and transients are the major events which are responsible for the tripping of the generators. In the present study, simulation models for wind, turbine, shaft, pitch mechanism, induction generator, and grid are developed using DIgSILENT. Using the turbine characteristics, a two-dimensional lookup table is designed to generate a reference pitch angle necessary to simulate the power curve of the passive stall controlled wind turbine. Various scenarios and their effects on the performance of the wind farm are studied and validated with the recorded data and waveforms. The simulation model will be useful for the designers for planning and development of the wind farm before implementation.

  3. Simulation and Study of Power Quality Issues in a Fixed Speed Wind Farm Substation

    Directory of Open Access Journals (Sweden)

    T. Magesh

    2015-01-01

    Full Text Available Power quality issues associated with the fixed speed wind farm substation located at Coimbatore district are investigated as the wind generators are tripping frequently. The investigations are carried out using two power quality analyzers, Fluke 435 and Dranetz PX5.8, with one of them connected at group control breaker of the 110 kV feeder and the other at the selected 0.69 kV generator busbar during the period of maximum power generation. From the analysis of the recorded data it is found that sag, swell, and transients are the major events which are responsible for the tripping of the generators. In the present study, simulation models for wind, turbine, shaft, pitch mechanism, induction generator, and grid are developed using DIgSILENT. Using the turbine characteristics, a two-dimensional lookup table is designed to generate a reference pitch angle necessary to simulate the power curve of the passive stall controlled wind turbine. Various scenarios and their effects on the performance of the wind farm are studied and validated with the recorded data and waveforms. The simulation model will be useful for the designers for planning and development of the wind farm before implementation.

  4. Intelligent approach to maximum power point tracking control strategy for variable-speed wind turbine generation system

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Whei-Min; Hong, Chih-Ming [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 80424 (China)

    2010-06-15

    To achieve maximum power point tracking (MPPT) for wind power generation systems, the rotational speed of wind turbines should be adjusted in real time according to wind speed. In this paper, a Wilcoxon radial basis function network (WRBFN) with hill-climb searching (HCS) MPPT strategy is proposed for a permanent magnet synchronous generator (PMSG) with a variable-speed wind turbine. A high-performance online training WRBFN using a back-propagation learning algorithm with modified particle swarm optimization (MPSO) regulating controller is designed for a PMSG. The MPSO is adopted in this study to adapt to the learning rates in the back-propagation process of the WRBFN to improve the learning capability. The MPPT strategy locates the system operation points along the maximum power curves based on the dc-link voltage of the inverter, thus avoiding the generator speed detection. (author)

  5. Application of Boost Converter to Increase the Speed Range of Dual-stator Winding Induction Generator in Wind Power Systems

    DEFF Research Database (Denmark)

    Kavousi, Ayoub; Fathi, S. Hamid; Milimonfared, Jafar

    2018-01-01

    In this paper, a topology using a Dual-stator Winding Induction Generator (DWIG) and a boost converter is proposed for the variable speed wind power application. At low rotor speeds, the generator saturation limits the voltage of the DWIG. Using a boost converter, higher DC voltage can be produced...... while the DWIG operates at Maximum Power Point Tracking (MPPT) even at low speed and low voltage conditions. Semiconductor Excitation Controller (SEC) of the DWIG utilizes Control-Winding Voltage Oriented Control (CWVOC) method to adjust the voltage, considering V/f characteristics. For the proposed...... topology, the SEC capacity and the excitation capacitor is optimized by analyzing the SEC reactive current considering wind turbine power-speed curve, V/f strategy, and the generator parameters. The method shows that the per-unit capacity of the SEC can be limited to the inverse of DWIG magnetizing...

  6. Second-order Sliding Mode Control of DFIG Based Variable Speed Wind Turbine for Maximum Power Point Tracking

    Institute of Scientific and Technical Information of China (English)

    Xiangjie Liu; Chengcheng Wang; Yaozhen Han

    2017-01-01

    This paper proposes a super-twisting second order sliding mode control scheme to maximize the wind energy capture of a doubly fed induction generator based variable speed wind turbine (VSWT) system, and minimize the reactive power simultaneously. Two second order sliding mode controllers are designed to achieve the control objectives, reduce mechanical stress and improve control accuracy. By regulating the generator rotor voltage, one controller makes the wind turbine rotor speed track the optimal speed, which can maximize power generation. The other maintains the rotor current at rated value to minimize the reactive power. A quadratic form Lyapunov function is adopted to determine the range of controller parameters and guarantee the finite time stability. Simulation results on a 1.5 MW doubly fed induction generator (DFIG)-based variable speed wind turbine demonstrate the validity of the proposed control strategy.

  7. Comparison of Wind Power Converter Reliability with Low-Speed and Medium-Speed Permanent-Magnet Synchronous Generators

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede; Franke, Toke

    2015-01-01

    of the turbine to the current and voltage loading of the each power semiconductor is achieved based on the synchronous generator modeling. Afterwards, a simplified approach to calculate the loss profile and the thermal profile is used to determine the most stressed power semiconductors in the converter. Finally...

  8. Mildly disabled persons with multiple sclerosis use similar net joint power strategies as healthy controls when walking speed increases.

    Science.gov (United States)

    Brincks, John; Christensen, Lars Ejsing; Rehnquist, Mette Voigt; Petersen, Jesper; Sørensen, Henrik; Dalgas, Ulrik

    2018-01-01

    To improve walking in persons with multiple sclerosis (MS), it is essential to understand the underlying mechanisms of walking. This study examined strategies in net joint power generated or absorbed by hip flexors, hip extensors, hip abductors, knee extensors, and plantar flexors in mildly disabled persons with MS and healthy controls at different walking speeds. Thirteen persons with MS and thirteen healthy controls participated and peak net joint power was calculated using 3D motion analysis. In general, no differences were found between speed-matched healthy controls and persons with MS, but the fastest walking speed was significantly higher in healthy controls (2.42 m/s vs. 1.70 m/s). The net joint power increased in hip flexors, hip extensors, hip abductors, knee extensors and plantar flexors in both groups, when walking speed increased. Significant correlations between changes in walking speed and changes in net joint power of plantar flexors, hip extensors and hip flexors existed in healthy controls and persons with MS, and in net knee extensor absorption power of persons with MS only. In contrast to previous studies, these findings suggest that mildly disabled persons with MS used similar kinetic strategies as healthy controls to increase walking speed.

  9. Improvement of low speed induction generator performances and reducing the power of excitation and voltage control system

    Energy Technology Data Exchange (ETDEWEB)

    Budisan, N. [Politechnica Univ. of Timisoara (Romania); Hentea, T.; Mahil, S. [Purdue Univ. Calumet, Hammond, IN (United States); Madescu, G. [Romanian Academy, Timisoara (Romania)

    1996-12-31

    In this paper we present the results of our investigations concerning the utilization of induction generators at very low speed. It is shown that, by proper design, it is possible to obtain high efficiency and high power factor values. The optimized induction generators require lower reactive power resulting in lower size and price of the excitation control system. 4 refs., 2 figs.

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

    DEFF Research Database (Denmark)

    Davari, Pooya; Yang, Yongheng; Zare, Firuz

    2016-01-01

    (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...

  11. An Appropriate Wind Model for Wind Integrated Power Systems Reliability Evaluation Considering Wind Speed Correlations

    Directory of Open Access Journals (Sweden)

    Rajesh Karki

    2013-02-01

    Full Text Available Adverse environmental impacts of carbon emissions are causing increasing concerns to the general public throughout the world. Electric energy generation from conventional energy sources is considered to be a major contributor to these harmful emissions. High emphasis is therefore being given to green alternatives of energy, such as wind and solar. Wind energy is being perceived as a promising alternative. This source of energy technology and its applications have undergone significant research and development over the past decade. As a result, many modern power systems include a significant portion of power generation from wind energy sources. The impact of wind generation on the overall system performance increases substantially as wind penetration in power systems continues to increase to relatively high levels. It becomes increasingly important to accurately model the wind behavior, the interaction with other wind sources and conventional sources, and incorporate the characteristics of the energy demand in order to carry out a realistic evaluation of system reliability. Power systems with high wind penetrations are often connected to multiple wind farms at different geographic locations. Wind speed correlations between the different wind farms largely affect the total wind power generation characteristics of such systems, and therefore should be an important parameter in the wind modeling process. This paper evaluates the effect of the correlation between multiple wind farms on the adequacy indices of wind-integrated systems. The paper also proposes a simple and appropriate probabilistic analytical model that incorporates wind correlations, and can be used for adequacy evaluation of multiple wind-integrated systems.

  12. Relationships between field-based measures of strength and power and golf club head speed.

    Science.gov (United States)

    Read, Paul J; Lloyd, Rhodri S; De Ste Croix, Mark; Oliver, Jon L

    2013-10-01

    Increased golf club head speed (CHS) has been shown to result in greater driving distances and is also correlated with golf handicap. The purpose of this study was to investigate the relationships between field-based measures of strength and power and golf CHS with a secondary aim to determine the reliability of the selected tests. A correlation design was used to assess the following variables: anthropometrics, squat jump (SJ) height and squat jump peak power (SJPP), unilateral countermovement jump (CMJ) heights (right leg countermovement jump and left leg countermovement jump [LLCMJ]), bilateral CMJ heights, countermovement jump peak power (CMJPP), and medicine ball seated throw (MBST) and medicine ball rotational throw (MBRT). Fouty-eight male subjects participated in the study (age: 20.1 ± 3.2 years, height: 1.76 ± 0.07 m, mass: 72.8 ± 7.8 kg, handicap: 5.8 ± 2.2). Moderate significant correlations were reported between CHS and MBRT (r = 0.67; p golf athletes using the proposed battery of field tests. Additionally, movements that are more concentrically dominant in nature may display stronger relationships with CHS due to MBST and SJ displaying the highest explained variance after a stepwise linear regression.

  13. Power maximization of an asynchronous wind turbine with a variable speed feeding a centrifugal pump

    International Nuclear Information System (INIS)

    Ouchbel, T.; Zouggar, S.; Elhafyani, M.L.; Seddik, M.; Oukili, M.; Aziz, A.; Kadda, F.Z.

    2014-01-01

    Highlights: • The pumping system studied contain a WT, a SEIG, an IM and a CP. • The system must ensure the water pumping in optimum conditions despite the wind speed. • A steady state study and a practical testing are performed to resolve the control law. • A MPPT is proposed on the basis of static converter SVC. - Abstract: This article focuses on the study of a pumping system compound of a wind turbine, a self-excited induction generator (SEIG), an induction motor (IM), and a centrifugal pump (CP), which aims to ensure the water pumping in optimum conditions regardless the wind speed. As a first step, a study in the steady and dynamic state to determine the control law is examined. As a second step, and so as to achieve a maximum energy flow we have proposed a Maximum Power Point Tracking (MPPT) algorithm based on a static converter SVC. As a final step, experimental and simulation results are discussed to show the reliability of the system proposed

  14. Small Horizontal Axis Wind Turbine under High Speed Operation: Study of Power Evaluation

    Science.gov (United States)

    Moh. M. Saad, Magedi; Mohd, Sofian Bin; Zulkafli, Mohd Fadhli Bin; Abdullah, Aslam Bin; Rahim, Mohammad Zulafif Bin; Subari, Zulkhairi Bin; Rosly, Nurhayati Binti

    2017-10-01

    Mechanical energy is produced through the rotation of wind turbine blades by air that convert the mechanical energy into electrical energy. Wind turbines are usually designed to be use for particular applications and design characteristics may vary depending on the area of use. The variety of applications is reflected on the size of turbines and their infrastructures, however, performance enhancement of wind turbine may start by analyzing the small horizontal axis wind turbine (SHAWT) under high wind speed operation. This paper analyzes the implementations of SHAWT turbines and investigates their performance in both simulation and real life. Depending on the real structure of the rotor geometry and aerodynamic test, the power performance of the SHAWT was simulated using ANSYS-FLUENT software at different wind speed up to 33.33 m/s (120km/h) in order to numerically investigate the actual turbine operation. Dynamic mesh and user define function (UDF) was used for revolving the rotor turbine via wind. Simulation results were further validated by experimental data and hence good matching was yielded. And for reducing the energy producing cost, car alternator was formed to be used as a small horizontal wind turbine. As a result, alternator-based turbine system was found to be a low-cost solution for exploitation of wind energy.

  15. Multifunctional TENG for Blue Energy Scavenging and Self-Powered Wind-Speed Sensor

    KAUST Repository

    Xi, Yi

    2017-02-17

    Triboelectric nanogenerator (TENG) has been considered to be a more effective technology to harvest various types of mechanic vibration energies such as wind energy, water energy in the blue energy, and so on. Considering the vast energy from the blue oceans, harvesting of the water energy has attracted huge attention. There are two major types of “mechanical” water energy, water wave energy in random direction and water flow kinetic energy. However, although the most reported TENG can be used to efficiently harvest one type of water energy, to simultaneously collect two or more types of such energy still remains challenging. In this work, two different freestanding, multifunctional TENGs are successfully developed that can be used to harvest three types of energies including water waves, air flowing, and water flowing. These two new TENGs designed in accordance with the same freestanding model yield the output voltages of 490 and ≈100 V with short circuit currents of 24 and 2.7 µA, respectively, when operated at a rotation frequency of 200 rpm and the movement frequency of 3 Hz. Moreover, the developed multifunctional TENG can also be explored as a self-powered speed sensor of wind by correlating the short-circuit current with the wind speed.

  16. The Predictive Power of Phonemic Awareness and Naming Speed for Early Dutch Word Recognition

    Science.gov (United States)

    Verhagen, Wim G. M.; Aarnoutse, Cor A. J.; van Leeuwe, Jan F. J.

    2009-01-01

    Effects of phonemic awareness and naming speed on the speed and accuracy of Dutch children's word recognition were investigated in a longitudinal study. Both the speed and accuracy of word recognition at the end of Grade 2 were predicted by naming speed from both kindergarten and Grade 1, after control for autoregressive relations, kindergarten…

  17. An Integrated Power-Efficient Active Rectifier With Offset-Controlled High Speed Comparators for Inductively Powered Applications

    Science.gov (United States)

    Lee, Hyung-Min; Ghovanloo, Maysam

    2011-01-01

    We present an active full-wave rectifier with offset-controlled high speed comparators in standard CMOS that provides high power conversion efficiency (PCE) in high frequency (HF) range for inductively powered devices. This rectifier provides much lower dropout voltage and far better PCE compared to the passive on-chip or off-chip rectifiers. The built-in offset-control functions in the comparators compensate for both turn-on and turn-off delays in the main rectifying switches, thus maximizing the forward current delivered to the load and minimizing the back current to improve the PCE. We have fabricated this active rectifier in a 0.5-μm 3M2P standard CMOS process, occupying 0.18 mm2 of chip area. With 3.8 V peak ac input at 13.56 MHz, the rectifier provides 3.12 V dc output to a 500 Ω load, resulting in the PCE of 80.2%, which is the highest measured at this frequency. In addition, overvoltage protection (OVP) as safety measure and built-in back telemetry capabilities have been incorporated in our design using detuning and load shift keying (LSK) techniques, respectively, and tested. PMID:22174666

  18. Long Term Effects of Different Training Modalities on Power, Speed, Skill and Anaerobic Capacity in Young Male Basketball Players

    OpenAIRE

    Balčiūnas, Mindaugas; Stonkus, Stanislovas; Abrantes, Catarina; Sampaio, Jaime

    2006-01-01

    The purpose of this study was to identify the effect of 4 months of different training modalities on power, speed, skill and anaerobic capacity in 15-16 year old male basketball players. Thirty five Lithuanian basketball players were randomly assigned into three groups: power endurance group (intermittent exercise, PE, n = 12), general endurance group (continuous exercise, GE, n = 11) and control group (regular basketball training, CG, n = 12). The power endurance model was based in basketbal...

  19. Exhaust emissions of volatile organic compounds of powered two-wheelers: effect of cold start and vehicle speed. Contribution to greenhouse effect and tropospheric ozone formation.

    Science.gov (United States)

    Costagliola, M Antonietta; Murena, Fabio; Prati, M Vittoria

    2014-01-15

    Powered two-wheeler (PTW) vehicles complying with recent European type approval standards (stages Euro 2 and Euro 3) were tested on chassis dynamometer in order to measure exhaust emissions of about 25 volatile organic compounds (VOCs) in the range C1-C7, including carcinogenic compounds as benzene and 1,3-butadiene. The fleet consists of a moped (engine capacity ≤ 50 cm(3)) and three fuel injection motorcycles of different engine capacities (150, 300 and 400 cm(3)). Different driving conditions were tested (US FPT cycle, constant speed). Due to the poor control of the combustion and catalyst efficiency, moped is the highest pollutant emitter. In fact, fuel injection strategy and three way catalyst with lambda sensor are able to reduce VOC motorcycles' emission of about one order of magnitude with respect to moped. Cold start effect, that is crucial for the assessment of actual emission of PTWs in urban areas, was significant: 30-51% of extra emission for methane. In the investigated speed range, moped showed a significant maximum of VOC emission factor at minimum speed (10 km/h) and a slightly decreasing trend from 20 to 60 km/h; motorcycles showed on the average a less significant peak at 10 km/h, a minimum at 30-40 km/h and then an increasing trend with a maximum emission factor at 90 km/h. Carcinogenic VOCs show the same pattern of total VOCs. Ozone Formation Potential (OFP) was estimated by using Maximum Incremental Reactivity scale. The greatest contribution to tropospheric ozone formation comes from alkenes group which account for 50-80% to the total OFP. VOC contribution effect on greenhouse effect is negligible with respect to CO2 emitted. © 2013.

  20. Shuttle Rudder/Speed Brake Power Drive Unit (PDU) Gear Scuffing Tests With Flight Gears

    Science.gov (United States)

    Proctor, Margaret P.; Oswald, Fred B.; Krants, Timothy L.

    2005-01-01

    Scuffing-like damage has been found on the tooth surfaces of gears 5 and 6 of the NASA space shuttle rudder/speed brake power drive unit (PDU) number 2 after the occurrence of a transient back-driving event in flight. Tests were conducted using a pair of unused spare flight gears in a bench test at operating conditions up to 2866 rpm and 1144 in.-lb at the input ring gear and 14,000 rpm and 234 in.-lb at the output pinion gear, corresponding to a power level of 52 hp. This test condition exceeds the maximum estimated conditions expected in a backdriving event thought to produce the scuffing damage. Some wear marks were produced, but they were much less severe than the scuffing damaged produced during shuttle flight. Failure to produce scuff damage like that found on the shuttle may be due to geometrical variations between the scuffed gears and the gears tested herein, more severe operating conditions during the flight that produced the scuff than estimated, the order of the test procedures, the use of new hydraulic oil, differences between the dynamic response of the flight gearbox and the bench-test gearbox, or a combination of these. This report documents the test gears, apparatus, and procedures, summarizes the test results, and includes a discussion of the findings, conclusions, and recommendations.

  1. Gait Speed rather than Dynapenia Is a Simple Indicator for Complex Care Needs: A Cross-sectional Study Using Minimum Data Set.

    Science.gov (United States)

    Huang, Tzu-Ya; Liang, Chih-Kuang; Shen, Hsiu-Chu; Chen, Hon-I; Liao, Mei-Chen; Chou, Ming-Yueh; Lin, Yu-Te; Chen, Liang-Kung

    2017-08-21

    The impact of dynapenia on the complexity of care for residents of long-term care facilities (LTCF) remains unclear. The present study evaluated associations between dynapenia, care problems and care complexity in 504 residents of Veterans Care Homes (VCHs) in Taiwan. Subjects with dynapenia, defined as low muscle strength (handgrip strength 1 m/s). Significantly slow gait speed was associated with RAP triggers, including cognitive loss, poor communication ability, rehabilitation needs, urinary incontinence, depressed mood, falls, pressure ulcers, and use of psychotropic drugs. In conclusion, slow gait speed rather than dynapenia is a simple indicator for higher complexity of care needs of older male LTCF residents.

  2. An Experimental Investigation On Minimum Compressive Strength Of Early Age Concrete To Prevent Frost Damage For Nuclear Power Plant Structures In Cold Climates

    International Nuclear Information System (INIS)

    Koh, Kyungtaek; Kim, Dogyeum; Park, Chunjin; Ryu, Gumsung; Park, Jungjun; Lee, Janghwa

    2013-01-01

    Concrete undergoing early frost damage in cold weather will experience significant loss of not only strength, but also of permeability and durability. Accordingly, concrete codes like ACI-306R prescribe a minimum compressive strength and duration of curing to prevent frost damage at an early age and secure the quality of concrete. Such minimum compressive strength and duration of curing are mostly defined based on the strength development of concrete. However, concrete subjected to frost damage at early age may not show a consistent relationship between its strength and durability. Especially, since durability of concrete is of utmost importance in nuclear power plant structures, this relationship should be imperatively clarified. Therefore, this study verifies the feasibility of the minimum compressive strength specified in the codes like ACI-306R by evaluating the strength development and the durability preventing the frost damage of early age concrete for nuclear power plant. The results indicate that the value of 5 MPa specified by the concrete standards like ACI-306R as the minimum compressive strength to prevent the early frost damage is reasonable in terms of the strength development, but seems to be inappropriate in the viewpoint of the resistance to chloride ion penetration and freeze-thaw. Consequently, it is recommended to propose a minimum compressive strength preventing early frost damage in terms of not only the strength development, but also in terms of the durability to secure the quality of concrete for nuclear power plants in cold climates

  3. An Experimental Investigation On Minimum Compressive Strength Of Early Age Concrete To Prevent Frost Damage For Nuclear Power Plant Structures In Cold Climates

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Kyungtaek; Kim, Dogyeum; Park, Chunjin; Ryu, Gumsung; Park, Jungjun; Lee, Janghwa [Korea Institute Construction Technology, Goyang (Korea, Republic of)

    2013-06-15

    Concrete undergoing early frost damage in cold weather will experience significant loss of not only strength, but also of permeability and durability. Accordingly, concrete codes like ACI-306R prescribe a minimum compressive strength and duration of curing to prevent frost damage at an early age and secure the quality of concrete. Such minimum compressive strength and duration of curing are mostly defined based on the strength development of concrete. However, concrete subjected to frost damage at early age may not show a consistent relationship between its strength and durability. Especially, since durability of concrete is of utmost importance in nuclear power plant structures, this relationship should be imperatively clarified. Therefore, this study verifies the feasibility of the minimum compressive strength specified in the codes like ACI-306R by evaluating the strength development and the durability preventing the frost damage of early age concrete for nuclear power plant. The results indicate that the value of 5 MPa specified by the concrete standards like ACI-306R as the minimum compressive strength to prevent the early frost damage is reasonable in terms of the strength development, but seems to be inappropriate in the viewpoint of the resistance to chloride ion penetration and freeze-thaw. Consequently, it is recommended to propose a minimum compressive strength preventing early frost damage in terms of not only the strength development, but also in terms of the durability to secure the quality of concrete for nuclear power plants in cold climates.

  4. Design optimization under uncertainty and speed variability for a piezoelectric energy harvester powering a tire pressure monitoring sensor

    Science.gov (United States)

    Toghi Eshghi, Amin; Lee, Soobum; Kazem Sadoughi, Mohammad; Hu, Chao; Kim, Young-Cheol; Seo, Jong-Ho

    2017-10-01

    Energy harvesting (EH) technologies to power small sized electronic devices are attracting great attention. Wasted energy in a vehicle’s rotating tire has a great potential to enable self-powered tire pressure monitoring sensors (TPMS). Piezoelectric type energy harvesters can be used to collect vibrational energy and power such systems. Due to the presence of harsh acceleration in a rotating tire, a design tradeoff needs to be studied to prolong the harvester’s fatigue life as well as to ensure sufficient power generation. However, the design by traditional deterministic design optimization (DDO) does not show reliable performance due to the lack of consideration of various uncertainty factors (e.g., manufacturing tolerances, material properties, and loading conditions). In this study, we address a new EH design formulation that considers the uncertainty in car speed, dimensional tolerances and material properties, and solve this design problem using reliability-based design optimization (RBDO). The RBDO problem is formulated to maximize compactness and minimize weight of a TPMS harvester while satisfying power and durability requirements. A transient analysis has been done to measure the time varying response of EH such as power generation, dynamic strain, and stress. A conservative design formulation is proposed to consider the expected power from varied speed and stress at higher speed. When compared to the DDO, the RBDO results show that the reliability of EH is increased significantly by scarifying the objective function. Finally, experimental test has been conducted to demonstrate the merits of RBDO design over DDO.

  5. CONTROLLING THE SPEED OF ROLLING CUTS IN CONDITIONS OF REDUCTION OF BRAKE POWER OF CAR RETARDERS

    Directory of Open Access Journals (Sweden)

    D. M. Kozachenko

    2016-06-01

    Full Text Available Purpose. The study aims to develop the requirements for organization of the marshalling process in the conditions when the power of retarder positions is less than the nominal one. Methodology. The research is carried out using the train traffic safety theory and mathematical modelling of hump processes. Findings. The current technical standard documents regulating the operational performance of humps do not contain direct instructions on how to proceed in the event of brake power loss by car retarders, thus creating threats to the traffic safety. This problem is quite acute for the Ukrainian railways in connection with a chronic shortage of funds for the repair and renewal of technical equipment, including the humps. At the same time, a significant drop in the volume of work leads to the fact that the hump required processing capacity can be provided in case of partial failure of retarders as well. Herewith the most important task is to ensure the breaking-up safety in conditions of parametric failures of retarders. The analysis of dangerous situations, the occurrence of which is possible at humps, as well as the modelling of cut rolling, allowed establishing the connection between the value of retarder tire pressing force on the car wheels and the breaking-up modes, providing the safety of marshalling process. The paper sets the application areas of such measures as the breaking-up speed reduction, breaking-up termination, the use of additional braking by block hangers. Originality. The originality of the work lies in the fact that it first obtained the complex of dependencies that determine the performance requirements for the power of hump retarders and allow the staff to enter the appropriate limits for breaking-up modes to ensure the marshalling process safety. Practical value. The results of the research can be used to supplement the «Instruction on the maintenance of facilities of mechanized and automated humps» in order to determine

  6. Modeling and Control of a DC-grid Hybrid Power System with Battery and Variable Speed Diesel Generators

    OpenAIRE

    Syverud, Tron Hansen

    2016-01-01

    Hybrid electric power systems (HPS) have successfully been integrated in the road-traffic industry due to enhanced efficiency and environmental benefits. Recently this concept has been implemented in the marine sector. In this master thesis, the construction of a DC hybrid power system for a marine vessel is outlined in detail. The HPS is developed in Matlbat/Simulink and comprises two set of diesel generators with variable speed, six-pulse diode bridges, a battery bank, bidire...

  7. The injection equipment of future high-speed DI diesel engines with respect to power and pollution requirements

    Energy Technology Data Exchange (ETDEWEB)

    Dolenc, A. (Monobloc Dieselmotoren GmbH, Vienna (AT))

    1990-01-01

    The development of high specific output DI diesel engines started at the low-speed end some 50 years ago primarily for marine and traction applications. Movement towards the high-speed end has been slow but steady with the majority of truck engines being very conservatively rated. There has been recent major effort on the automotive car and light commercial vehicle diesel application leading to lightweight DI diesel engines with an engine speed of 4000-5000 r/min and a rated power of 50 kW/litre displacement. These are expected to be on the market in a short period of time. The key point of this development has been the injection equipment including combustion control. In this area the use of modulated injection has the possibility of solving power and pollution requirements. (author).

  8. A novel 2 T P-channel nano-crystal memory for low power/high speed embedded NVM applications

    International Nuclear Information System (INIS)

    Zhang Junyu; Wang Yong; Liu Jing; Zhang Manhong; Xu Zhongguang; Huo Zongliang; Liu Ming

    2012-01-01

    We introduce a novel 2 T P-channel nano-crystal memory structure for low power and high speed embedded non-volatile memory (NVM) applications. By using the band-to-band tunneling-induced hot-electron (BTBTIHE) injection scheme, both high-speed and low power programming can be achieved at the same time. Due to the use of a select transistor, the 'erased states' can be set to below 0 V, so that the periphery HV circuit (high-voltage generating and management) and read-out circuit can be simplified. Good memory cell performance has also been achieved, including a fast program/erase (P/E) speed (a 1.15 V memory window under 10 μs program pulse), an excellent data retention (only 20% charge loss for 10 years). The data shows that the device has strong potential for future embedded NVM applications. (semiconductor devices)

  9. A low power high speed radiation hard serializer for High Energy Physics experiments

    CERN Document Server

    AUTHOR|(CDS)2080243; Marchioro, Alessandro; Ottavi, Marco

    This Ph.D. thesis focuses on the development and the characterization of novel solutions for electronic systems for high-speed data transmission in extremely high radio-active environment (e.g. high energy physics application). The text proposes two alternative full-custom solutions for a fundamental enabling block for a lowpower serial data transmission system, the serializer. This block will find place in a future transceiver conceived for the future upgraded phase of the Large Hadron Collider, or LHC, at CERN. The first solution proposed, called “triple module redundancy”, is based on hardware redundancy, a well-known solution, to obtain protection against the temporary malfunctioning induced by radiation. In the second case a new architecture, called “code protected”, is proposed. This architecture takes advantage of the error correction code present in the data word to obtain radiation robustness on data and some parts of the control logic and to further reduce the power consumption. A test chip ...

  10. Intraspecific variation in aerobic and anaerobic locomotion: gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata) do not exhibit a trade-off between maximum sustained swimming speed and minimum cost of transport

    Science.gov (United States)

    Svendsen, Jon C.; Tirsgaard, Bjørn; Cordero, Gerardo A.; Steffensen, John F.

    2015-01-01

    Intraspecific variation and trade-off in aerobic and anaerobic traits remain poorly understood in aquatic locomotion. Using gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata), both axial swimmers, this study tested four hypotheses: (1) gait transition from steady to unsteady (i.e., burst-assisted) swimming is associated with anaerobic metabolism evidenced as excess post exercise oxygen consumption (EPOC); (2) variation in swimming performance (critical swimming speed; Ucrit) correlates with metabolic scope (MS) or anaerobic capacity (i.e., maximum EPOC); (3) there is a trade-off between maximum sustained swimming speed (Usus) and minimum cost of transport (COTmin); and (4) variation in Usus correlates positively with optimum swimming speed (Uopt; i.e., the speed that minimizes energy expenditure per unit of distance traveled). Data collection involved swimming respirometry and video analysis. Results showed that anaerobic swimming costs (i.e., EPOC) increase linearly with the number of bursts in S. aurata, with each burst corresponding to 0.53 mg O2 kg−1. Data are consistent with a previous study on striped surfperch (Embiotoca lateralis), a labriform swimmer, suggesting that the metabolic cost of burst swimming is similar across various types of locomotion. There was no correlation between Ucrit and MS or anaerobic capacity in S. aurata indicating that other factors, including morphological or biomechanical traits, influenced Ucrit. We found no evidence of a trade-off between Usus and COTmin. In fact, data revealed significant negative correlations between Usus and COTmin, suggesting that individuals with high Usus also exhibit low COTmin. Finally, there were positive correlations between Usus and Uopt. Our study demonstrates the energetic importance of anaerobic metabolism during unsteady swimming, and provides intraspecific evidence that superior maximum sustained swimming speed is associated with superior swimming economy and

  11. Low-latency video transmission over high-speed WPANs based on low-power video compression

    DEFF Research Database (Denmark)

    Belyaev, Evgeny; Turlikov, Andrey; Ukhanova, Ann

    2010-01-01

    This paper presents latency-constrained video transmission over high-speed wireless personal area networks (WPANs). Low-power video compression is proposed as an alternative to uncompressed video transmission. A video source rate control based on MINMAX quality criteria is introduced. Practical...

  12. An improved synchronous reference frame phase-locked loop for stand-alone variable speed constant frequency power generation systems

    DEFF Research Database (Denmark)

    Liu, Yi; Xu, Wei; Ke, Longzhang

    2017-01-01

    The phase-locked loop (PLL) based on conventional synchronous reference frame, i.e. dqPLL, is usually employed in grid-connected variable speed constant frequency (VSCF) power generation systems (PGSs). However, the voltage amplitude drop of stand-alone PGSs is often greater than that of the grid...

  13. CHANGE ON SPEED AIR CHARACTERISTICS THE POWER INDICATOR INDEXES OF PNEUMATIC ENGINE WITHOUT HEATING THE CHARGE DURING THE ADMITTANCE

    Directory of Open Access Journals (Sweden)

    A. Voronkov

    2014-10-01

    Full Text Available The experimental data on change according to speed characteristics of power indicator indexes of the four cylinder pneumatic engine D/S = 76/66 with a slide-valve air distributor at unchangeable temperature of compressed input air is considered.

  14. Using wind speed from a blade-mounted flow sensor for power and load assessment on modern wind turbines

    Directory of Open Access Journals (Sweden)

    M. M. Pedersen

    2017-11-01

    Full Text Available In this paper an alternative method to evaluate power performance and loads on wind turbines using a blade-mounted flow sensor is investigated. The hypothesis is that the wind speed measured at the blades has a high correlation with the power and loads such that a power or load assessment can be performed from a few hours or days of measurements.In the present study a blade-mounted five-hole pitot tube is used as the flow sensor as an alternative to the conventional approach, where the reference wind speed is either measured at a nearby met mast or on the nacelle using lidar technology or cup anemometers. From the flow sensor measurements, an accurate estimate of the wind speed at the rotor plane can be obtained. This wind speed is disturbed by the presence of the wind turbine, and it is therefore different from the free-flow wind speed. However, the recorded wind speed has a high correlation with the actual power production as well as the flap-wise loads as it is measured close to the blade where the aerodynamic forces are acting.Conventional power curves are based on at least 180 h of 10 min mean values, but using the blade-mounted flow sensor both the observation average time and the overall assessment time can potentially be shortened. The basis for this hypothesis is that the sensor is able to provide more observations with higher accuracy, as the sensor follows the rotation of the rotor and because of the high correlation between the flow at the blades and the power production. This is the research question addressed in this paper.The method is first tested using aeroelastic simulations where the dependence of the radial position and effect of multiple blade-mounted flow sensors are also investigated. Next the method is evaluated on the basis of full-scale measurements on a pitch-regulated, variable-speed 3.6 MW wind turbine.It is concluded that the wind speed derived from the blade-mounted flow sensor is highly correlated with the

  15. Long Term Effects of Different Training Modalities on Power, Speed, Skill and Anaerobic Capacity in Young Male Basketball Players

    Science.gov (United States)

    Balčiūnas, Mindaugas; Stonkus, Stanislovas; Abrantes, Catarina; Sampaio, Jaime

    2006-01-01

    The purpose of this study was to identify the effect of 4 months of different training modalities on power, speed, skill and anaerobic capacity in 15-16 year old male basketball players. Thirty five Lithuanian basketball players were randomly assigned into three groups: power endurance group (intermittent exercise, PE, n = 12), general endurance group (continuous exercise, GE, n = 11) and control group (regular basketball training, CG, n = 12). The power endurance model was based in basketball game external structure whereas the general endurance model was based in continuous actions that frequently occur during the basketball game. The training models were used for 16 weeks in sessions conducted 3 times a week during 90 minutes each in the competition period. The following tests were performed: 20 m speed run, Squat jump, Countermovement jump, Running-based Anaerobic Sprint Test (RAST), 2 min. shooting test and the Shuttle ball-dribbling test. A 3×2 repeated measures ANOVA revealed no statistically significant differences in the 20 m speed run, Squat jump and Countermovement jump (p > 0.05). On the other hand, RAST showed significant increases in PE, with greater increases during the 5th and 6th runs. The PE training model also produced a significant improvement in the shuttle ball-dribbling test (48.7 ± 1.5 in the pretest, 45.5 ± 1.3 in the posttest, p training modalities were able to maintain initial values of speed and power, however, the anaerobic capacity and skill increased only in the players from the power endurance group. Therefore, the power endurance training (intermittent high intensity exercise) may be more beneficial to prepare junior players according to the game cardiovascular and metabolic specific determinants. Key Points Power endurance training produced significant increases in anaerobic capacity during the competition period. Power endurance training did not have a detrimental effect on power or speed performance during the competition

  16. Long term effects of different training modalities on power, speed, skill and anaerobic capacity in young male basketball players.

    Science.gov (United States)

    Balčiūnas, Mindaugas; Stonkus, Stanislovas; Abrantes, Catarina; Sampaio, Jaime

    2006-01-01

    The purpose of this study was to identify the effect of 4 months of different training modalities on power, speed, skill and anaerobic capacity in 15-16 year old male basketball players. Thirty five Lithuanian basketball players were randomly assigned into three groups: power endurance group (intermittent exercise, PE, n = 12), general endurance group (continuous exercise, GE, n = 11) and control group (regular basketball training, CG, n = 12). The power endurance model was based in basketball game external structure whereas the general endurance model was based in continuous actions that frequently occur during the basketball game. The training models were used for 16 weeks in sessions conducted 3 times a week during 90 minutes each in the competition period. The following tests were performed: 20 m speed run, Squat jump, Countermovement jump, Running-based Anaerobic Sprint Test (RAST), 2 min. shooting test and the Shuttle ball-dribbling test. A 3×2 repeated measures ANOVA revealed no statistically significant differences in the 20 m speed run, Squat jump and Countermovement jump (p > 0.05). On the other hand, RAST showed significant increases in PE, with greater increases during the 5(th) and 6(th) runs. The PE training model also produced a significant improvement in the shuttle ball-dribbling test (48.7 ± 1.5 in the pretest, 45.5 ± 1.3 in the posttest, p training modalities were able to maintain initial values of speed and power, however, the anaerobic capacity and skill increased only in the players from the power endurance group. Therefore, the power endurance training (intermittent high intensity exercise) may be more beneficial to prepare junior players according to the game cardiovascular and metabolic specific determinants. Key PointsPower endurance training produced significant increases in anaerobic capacity during the competition period.Power endurance training did not have a detrimental effect on power or speed performance during the competition

  17. Influence of local wind speed and direction on wind power dynamics – Application to offshore very short-term forecasting

    DEFF Research Database (Denmark)

    Gallego, Cristobal; Pinson, Pierre; Madsen, Henrik

    2011-01-01

    Wind power time series usually show complex dynamics mainly due to non-linearities related to the wind physics and the power transformation process in wind farms. This article provides an approach to the incorporation of observed local variables (wind speed and direction) to model some of these e......Wind power time series usually show complex dynamics mainly due to non-linearities related to the wind physics and the power transformation process in wind farms. This article provides an approach to the incorporation of observed local variables (wind speed and direction) to model some...... on one-step ahead forecasting and a time series resolution of 10 min. It has been found that the local wind direction contributes to model some features of the prevailing winds, such as the impact of the wind direction on the wind variability, whereas the non-linearities related to the power...... transformation process can be introduced by considering the local wind speed. In both cases, conditional parametric models showed a better performance than the one achieved by the regime-switching strategy. The results attained reinforce the idea that each explanatory variable allows the modelling of different...

  18. Rotor equivalent wind speed for power curve measurement – comparative exercise for IEA Wind Annex 32

    DEFF Research Database (Denmark)

    Wagner, Rozenn; Cañadillas, B.; Clifton, A.

    2014-01-01

    was the definition of the segment area used as weighting for the wind speeds measured at the various heights in the calculation of the REWS. This comparative exercise showed that the REWS method results in a significant difference compared to the standard method using the wind speed at hub height in conditions...

  19. Rotor aerodynamic power limits at low tip speed ratio using CFD

    DEFF Research Database (Denmark)

    Mikkelsen, Robert Flemming; Sarmast, Sasan; Henningson, Dan

    2014-01-01

    . In the present work we study in detail, using a CFD actuator line model, the flow behavior for rotors at small tip speed ratios. It is shown that the excessive swirl appearing towards the rotor center at small tip speed ratios generates vortex breakdown, causing a recirculating zone in the wake that limits...

  20. LONG TERM EFFECTS OF DIFFERENT TRAINING MODALITIES ON POWER, SPEED, SKILL AND ANAEROBIC CAPACITY IN YOUNG MALE BASKETBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Mindaugas Balciunas

    2006-03-01

    Full Text Available The purpose of this study was to identify the effect of 4 months of different training modalities on power, speed, skill and anaerobic capacity in 15-16 year old male basketball players. Thirty five Lithuanian basketball players were randomly assigned into three groups: power endurance group (intermittent exercise, PE, n = 12, general endurance group (continuous exercise, GE, n = 11 and control group (regular basketball training, CG, n = 12. The power endurance model was based in basketball game external structure whereas the general endurance model was based in continuous actions that frequently occur during the basketball game. The training models were used for 16 weeks in sessions conducted 3 times a week during 90 minutes each in the competition period. The following tests were performed: 20 m speed run, Squat jump, Countermovement jump, Running-based Anaerobic Sprint Test (RAST, 2 min. shooting test and the Shuttle ball-dribbling test. A 3×2 repeated measures ANOVA revealed no statistically significant differences in the 20 m speed run, Squat jump and Countermovement jump (p > 0.05. On the other hand, RAST showed significant increases in PE, with greater increases during the 5th and 6th runs. The PE training model also produced a significant improvement in the shuttle ball-dribbling test (48.7 ± 1.5 in the pretest, 45.5 ± 1.3 in the posttest, p < 0.05. Globally, our results suggest that both training modalities were able to maintain initial values of speed and power, however, the anaerobic capacity and skill increased only in the players from the power endurance group. Therefore, the power endurance training (intermittent high intensity exercise may be more beneficial to prepare junior players according to the game cardiovascular and metabolic specific determinants

  1. Effect of the Power Balance® hologram on balance, flexibility, strength and speed-coordination among university students

    Directory of Open Access Journals (Sweden)

    Rafael Merino Marban, Daniel Mayorga Vega, Emilio Fernández Rodríguez, Francisco José Santana Pérez, Oscar Romero Ramos

    2011-01-01

    Full Text Available Based on the body’s energy field, the inventors of Power Balance® have created a hologram that theoretically runs through frequencies that are in our natural environment. Its creators say that people may experience improve balance, strength, flexibility, endurance, concentration, coordination and recovery time, among others. The purpose of this research is to evaluate the effect of Power Balance® hologram on balance, flexibility, strength and speed-coordination in university students. A sample of 105 young volunteers’ physical education students (age 20.91 ± 3.36 years, mass 69.69 ± 11.35 kg, height 171.70 ± 8.07 cm was used. A between-group experimental design with double-blind control group was used to evaluate the possible effects of the Power Balance ® on the dynamic balance, flexibility, abdominal strength, endurance and speed-coordination measured with the Dynamic Balance Test, Sit and Reach, Sit-ups in 30 seconds and Race 10 x 5 m, respectively. A t of Student for independent and dependent samples was used to assess the potential effects between-group and intra-group, respectively. Power Balance®’s hologram produces no significant effects on the balance, flexibility, strength and speed-coordination among university students

  2. Prediction of wind power potential by wind speed probability distribution in a hilly terrain near Bh

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Siraj; Diwakar, Nilesh

    2010-09-15

    Daily wind speed data in metre per second and its direction of flow in degree were recorded from of the India Meteorological Department for a site near the Bhopal Airport for the period of eleven years. The influence of roughness of the terrain, obstacles and topography in terms of contour for the area were also taken into consideration. These data were analysed using WAsP programme and regional wind climate of the area was determined. It is seen from the analysis of the wind speed data and keeping the topographical variation of terrain, exploitable wind speed is experienced at 50 m.

  3. Game method application efficiency for speed and power capability development of trampoline athletes at the initial training stage

    Directory of Open Access Journals (Sweden)

    Alfia Deineko

    2017-06-01

    Full Text Available Purpose: to prove the effectiveness of using the game method for speed and power capability development of trampoline athletes at the initial training stage. Material & Methods: in the article the materials of the research that was carried out with the help of pedagogical testing of trampoliners of 7–8 years on the basis of the Children and Youth Sports School No. 7, Trampoline Department of Kharkov. Results: conducted pedagogical experiment showed the effectiveness of the developed methodology for the development of speed-strength abilities of trampoline athletes at the initial training stage using the game method. Conclusion: results of the experiment confirm the importance of the use of the game method for the development of speed-strength abilities in the initial training of young trampolines, which further affects the level of their technical preparedness and the effectiveness of competition activities.

  4. Exploiting maximum energy from variable speed wind power generation systems by using an adaptive Takagi-Sugeno-Kang fuzzy model

    International Nuclear Information System (INIS)

    Galdi, V.; Piccolo, A.; Siano, P.

    2009-01-01

    Nowadays, incentives and financing options for developing renewable energy facilities and the new development in variable speed wind technology make wind energy a competitive source if compared with conventional generation ones. In order to improve the effectiveness of variable speed wind systems, adaptive control systems able to cope with time variances of the system under control are necessary. On these basis, a data driven designing methodology for TSK fuzzy models design is presented in this paper. The methodology, on the basis of given input-output numerical data, generates the 'best' TSK fuzzy model able to estimate with high accuracy the maximum extractable power from a variable speed wind turbine. The design methodology is based on fuzzy clustering methods for partitioning the input-output space combined with genetic algorithms (GA), and recursive least-squares (LS) optimization methods for model parameter adaptation

  5. Powering and Motion Predictions of High Speed Sea Lift (HSSL) Ships

    National Research Council Canada - National Science Library

    Gorski, Joseph; Miller, Ronald; Carrica, Pablo; Kandasamy, Mani; Stern, Fred

    2007-01-01

    High Speed Sea Lift (HSSL) is an important area of in terest for the US Navy. Computational tools are needed to predict the hydrodynamics of these configurations for their proper design and analysis in many areas including...

  6. Speed endurance training is a powerful stimulus for physiological adaptations and performance improvements of athletes

    DEFF Research Database (Denmark)

    Iaia, F. M.; Bangsbo, Jens

    2010-01-01

    the oxidative capacity and improve intense short-duration/repeated high-intensity exercise performance lasting 30 s to 4 min, as it occurs in a number of sports. When combined with a basic volume of training including some aerobic high-intensity sessions, speed endurance training is also useful in enhancing......The present article reviews the physiological and performance effects of speed endurance training consisting of exercise bouts at near maximal intensities in already trained subjects. Despite a reduction in training volume, speed endurance training of endurance-trained athletes can maintain...... performance during longer events, e.g. 40 K cycling and 10 K running. Athletes in team sports involving intense exercise actions and endurance aspects can also benefit from performing speed endurance training. These improvements don't appear to depend on changes in maximum oxygen uptake (VO2max), muscle...

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

    Directory of Open Access Journals (Sweden)

    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%.

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

    Science.gov (United States)

    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%.

  9. Investigation on a Power Coupling Steering System for Dual-Motor Drive Tracked Vehicles Based on Speed Control

    Directory of Open Access Journals (Sweden)

    Li Zhai

    2017-08-01

    Full Text Available Double-motor drive tracked vehicles (2MDTV are widely used in the tracked vehicle industry due to the development of electric vehicle drive systems. The aim of this paper is to solve the problem of insufficient propulsion motor torque in low-speed, small-radius steering and insufficient power in high-speed large-radius steering. In order to do this a new type of steering system with a coupling device is designed and a closed-loop control strategy based on speed is adopted to improve the lateral stability of the vehicle. The work done entails modeling and simulating the 2MDTV and the proposed control strategy in RecurDyn and Matlab/Simulink. The simulation results show that the 2MDTV with the coupling device outputs more torque and power in both steering cases compared to the 2MDTV without the coupling device, and the steering stability of the vehicle is improved by using the strategy based on speed.

  10. Wind Turbine Down-regulation Strategy for Minimum Wake Deficit

    DEFF Research Database (Denmark)

    Ma, Kuichao; Zhu, Jiangsheng; N. Soltani, Mohsen

    2017-01-01

    Down-regulation mode of wind turbine is commonly used no matter for the reserve power for supporting ancillary service to the grid, power optimization in wind farm or reducing power loss in the fault condition. It is also a method to protect faulty turbine. A down-regulation strategy based...... on minimum wake deficit is proposed in this paper, for the power improvement of the downwind turbine in low and medium wind speed region. The main idea is to operate turbine work at an appropriate operating point through rotor speed and torque control. The effectiveness of the strategy is verified...... by comparing with maximum rotor speed strategy. The result shows that the proposed strategy can improve the power of downwind turbine effectively....

  11. L1 Adaptive Speed Control of a Small Wind Energy Conversion System for Maximum Power Point Tracking

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Rasmussen, Claus Nygaard

    2014-01-01

    This paper presents the design of an L1 adaptive controller for maximum power point tracking (MPPT) of a small variable speed Wind Energy Conversion System (WECS). The proposed controller generates the optimal torque command for the vector controlled generator side converter (GSC) based on the wi......) is used to carry out case studies using Matlab/Simulink. The case study results show that the designed L1 adaptive controller has good tracking performance even with unmodeled dynamics and in the presence of parameter uncertainties and unknown disturbances.......This paper presents the design of an L1 adaptive controller for maximum power point tracking (MPPT) of a small variable speed Wind Energy Conversion System (WECS). The proposed controller generates the optimal torque command for the vector controlled generator side converter (GSC) based on the wind...

  12. Self-Powered Wind Sensor System for Detecting Wind Speed and Direction Based on a Triboelectric Nanogenerator.

    Science.gov (United States)

    Wang, Jiyu; Ding, Wenbo; Pan, Lun; Wu, Changsheng; Yu, Hua; Yang, Lijun; Liao, Ruijin; Wang, Zhong Lin

    2018-04-24

    The development of the Internet of Things has brought new challenges to the corresponding distributed sensor systems. Self-powered sensors that can perceive and respond to environmental stimuli without an external power supply are highly desirable. In this paper, a self-powered wind sensor system based on an anemometer triboelectric nanogenerator (a-TENG, free-standing mode) and a wind vane triboelectric nanogenerator (v-TENG, single-electrode mode) is proposed for simultaneously detecting wind speed and direction. A soft friction mode is adopted instead of a typical rigid friction for largely enhancing the output performance of the TENG. The design parameters including size, unit central angle, and applied materials are optimized to enhance sensitivity, resolution, and wide measurement scale. The optimized a-TENG could deliver an open-circuit voltage of 88 V and short-circuit current of 6.3 μA, corresponding to a maximum power output of 0.47 mW (wind speed of 6.0 m/s), which is capable of driving electronics for data transmission and storage. The current peak value of the a-TENG signal is used for analyzing wind speed for less energy consumption. Moreover, the output characteristics of a v-TENG are further explored, with six actual operation situations, and the v-TENG delivers fast response to the incoming wind and accurately outputs the wind direction data. As a wind sensor system, wind speed ranging from 2.7 to 8.0 m/s can be well detected (consistent with a commercial sensor) and eight regular directions can be monitored. Therefore, the fabricated wind sensor system has great potential in wireless environmental monitoring applications.

  13. Flicker Mitigation by Active Power Control of Variable-Speed Wind Turbines With Full-Scale Back-to-Back Power Converters

    DEFF Research Database (Denmark)

    Hu, Weihao; Chen, Zhe; Wang, Zhaoan

    2009-01-01

    /EMTDC. Flicker emission of this system is investigated. Reactive power compensation is mostly adopted for flicker mitigation. However, the flicker mitigation technique shows its limits, when the grid impedance angle is low in some distribution networks. A new method of flicker mitigation by controlling active...... power is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the dc-link voltage of the full-scale converter. Simulation results show that damping the 3p active power oscillation by using the flicker mitigation controller...... is an effective means for flicker mitigation of variable-speed wind turbines with full-scale back-to-back power converters during continuous operation....

  14. Modelling of wind power plant controller, wind speed time series, aggregation and sample results

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Altin, Müfit; Cutululis, Nicolaos Antonio

    This report describes the modelling of a wind power plant (WPP) including its controller. Several ancillary services like inertial response (IR), power oscillation damping (POD) and synchronising power (SP) are implemented. The focus in this document is on the performance of the WPP output...... and not the impact of the WPP on the power system. By means of simulation tests, the capability of the implemented wind power plant model to deliver ancillary services is investigated....

  15. High-throughput machining using a high-average power ultrashort pulse laser and high-speed polygon scanner

    Science.gov (United States)

    Schille, Joerg; Schneider, Lutz; Streek, André; Kloetzer, Sascha; Loeschner, Udo

    2016-09-01

    High-throughput ultrashort pulse laser machining is investigated on various industrial grade metals (aluminum, copper, and stainless steel) and Al2O3 ceramic at unprecedented processing speeds. This is achieved by using a high-average power picosecond laser in conjunction with a unique, in-house developed polygon mirror-based biaxial scanning system. Therefore, different concepts of polygon scanners are engineered and tested to find the best architecture for high-speed and precision laser beam scanning. In order to identify the optimum conditions for efficient processing when using high-average laser powers, the depths of cavities made in the samples by varying the processing parameter settings are analyzed and, from the results obtained, the characteristic removal values are specified. For overlapping pulses of optimum fluence, the removal rate is as high as 27.8 mm3/min for aluminum, 21.4 mm3/min for copper, 15.3 mm3/min for stainless steel, and 129.1 mm3/min for Al2O3, when a laser beam of 187 W average laser powers irradiates. On stainless steel, it is demonstrated that the removal rate increases to 23.3 mm3/min when the laser beam is very fast moving. This is thanks to the low pulse overlap as achieved with 800 m/s beam deflection speed; thus, laser beam shielding can be avoided even when irradiating high-repetitive 20-MHz pulses.

  16. Effect of Laser Power and Scan Speed on Melt Pool Characteristics of Commercially Pure Titanium (CP-Ti)

    Science.gov (United States)

    Kusuma, Chandrakanth; Ahmed, Sazzad H.; Mian, Ahsan; Srinivasan, Raghavan

    2017-07-01

    Selective laser melting (SLM) is an additive manufacturing technique that creates complex parts by selectively melting metal powder layer-by-layer using a laser. In SLM, the process parameters decide the quality of the fabricated component. In this study, single beads of commercially pure titanium (CP-Ti) were melted on a substrate of the same material using an in-house built SLM machine. Multiple combinations of laser power and scan speed were used for single bead fabrication, while the laser beam diameter and powder layer thickness were kept constant. This experimental study investigated the influence of laser power, scan speed, and laser energy density on the melt pool formation, surface morphology, geometry (width and height), and hardness of solidified beads. In addition, the observed unfavorable effect such as inconsistency in melt pool width formation is discussed. The results show that the quality, geometry, and hardness of solidified melt pool are significantly affected by laser power, scanning speed, and laser energy density.

  17. Resurrecting the Power-law, Intermediate, and Logamediate Inflations in the DBI Scenario with Constant Sound Speed

    Science.gov (United States)

    Amani, Roonak; Rezazadeh, Kazem; Abdolmaleki, Asrin; Karami, Kayoomars

    2018-02-01

    We investigate the power-law, intermediate, and logamediate inflationary models in the framework of DBI non-canonical scalar field with constant sound speed. In the DBI setting, we first represent the power spectrum of both scalar density and tensor gravitational perturbations. Then, we derive different inflationary observables including the scalar spectral index n s , the running of the scalar spectral index {{dn}}s/d{ln}k, and the tensor-to-scalar ratio r. We show that the 95% CL constraint of the Planck 2015 T + E data on the non-Gaussianity parameter {f}{NL}{DBI} leads to the sound speed bound {c}s≥slant 0.087 in the DBI inflation. Moreover, our results imply that, although the predictions of the power-law, intermediate, and logamediate inflations in the standard canonical framework (c s = 1) are not consistent with the Planck 2015 data, in the DBI scenario with constant sound speed {c}srunning of the scalar spectral index and find that it is compatible with the 95% CL constraint from the Planck 2015 TT,TE,EE+lowP data.

  18. BEGA Starter/Alternator - Vector Control Implementation and Performance for Wide Speed Range at Unity Power Factor Operation

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Boldea, Ion; Coroban-Schramel, Vasile

    2008-01-01

    Biaxial Excitation Generator for Automobile (BEGA) is proposed as a solution for integrated starter/alternator systems used in hybrid electric vehicles (HEVs). This paper demonstrates through experiments and simulations that BEGA has a very large constant power speed range (CPSR), theoretically...... to infinite. A vector control structure is proposed for BEGA operation during motoring and generating, at unity power factor with zero d-axis current (id) and zero q-axis flux (Ψq) control. In such conditions BEGA behaves like a truly dc. brush machine (with zero reactance in steady state !). A high iq...

  19. BEGA Starter/Alternator—Vector Control Implementation and Performance for Wide Speed Range at Unity Power Factor Operation

    DEFF Research Database (Denmark)

    Boldea, Ion; Coroban-Schramel, Vasile; Andreescu, Gheorghe-Daniel

    2010-01-01

    The Biaxial Excitation Generator for Automobiles (BEGA) is proposed as a solution for integrated starter/alternator systems used in hybrid electric vehicles. This paper demonstrates through experiments and simulations that BEGA has a very large constant power speed range. A vector control structure...... is proposed for BEGA operation during motoring and generating, at unity power factor with zero d-axis current (id) and zero q-axis flux (Ψq) control. In such conditions, BEGA behaves like a separately excited dc brush(commutator) machine, in the sense that no stator inductance voltage drop occurs...

  20. Equal Power Distribution and Dynamic Subcarrier Assignment in OFDM Using Minimum Channel Gain Flow with Robust Optimization Uncertain Demand

    OpenAIRE

    Tun, F. A. Hla Myo; Phyo, S. B. Aye Thandar; Naing, T. C. Zaw Min

    2010-01-01

    In this paper, the minimum channel gain flow with uncertainty in the demand vector is examined. The approach is based on a transformation of uncertainty in the demand vector to uncertainty in the gain vector. OFDM systems are known to overcome the impairment of the wireless channel by splitting the given system bandwidth into parallel sub-carriers, on which data-symbols can be transmitted simultaneously. This enables the possibility of enhancing the system's performance by deploying adaptive ...

  1. A New Fault Diagnosis Algorithm for PMSG Wind Turbine Power Converters under Variable Wind Speed Conditions

    Directory of Open Access Journals (Sweden)

    Yingning Qiu

    2016-07-01

    Full Text Available Although Permanent Magnet Synchronous Generator (PMSG wind turbines (WTs mitigate gearbox impacts, they requires high reliability of generators and converters. Statistical analysis shows that the failure rate of direct-drive PMSG wind turbines’ generators and inverters are high. Intelligent fault diagnosis algorithms to detect inverters faults is a premise for the condition monitoring system aimed at improving wind turbines’ reliability and availability. The influences of random wind speed and diversified control strategies lead to challenges for developing intelligent fault diagnosis algorithms for converters. This paper studies open-circuit fault features of wind turbine converters in variable wind speed situations through systematic simulation and experiment. A new fault diagnosis algorithm named Wind Speed Based Normalized Current Trajectory is proposed and used to accurately detect and locate faulted IGBT in the circuit arms. It is compared to direct current monitoring and current vector trajectory pattern approaches. The results show that the proposed method has advantages in the accuracy of fault diagnosis and has superior anti-noise capability in variable wind speed situations. The impact of the control strategy is also identified. Experimental results demonstrate its applicability on practical WT condition monitoring system which is used to improve wind turbine reliability and reduce their maintenance cost.

  2. THE FUZZY LOGIC BASED POWER INJECTION INTO ROTOR CIRCUIT FOR INSTANTANEOUS HIGH TORQUE AND SPEED CONTROL IN INDUCTION MACHINES

    Directory of Open Access Journals (Sweden)

    Selami KESLER

    2009-01-01

    Full Text Available The power flow of the rotor circuit is controlled by different methods in induction machines used for producing high torque in applications involved great power and constant output power with constant frequency in wind turbines. The voltage with slip frequency can be applied on rotor windings to produce controlled high torque and obtain optimal power factor and speed control. In this study, firstly, the dynamic effects of the voltage applying on rotor windings through the rings in slip-ring induction machines are researched and undesirable aspects of the method are exposed with simulations supported by experiments. Afterwards, a fuzzy logic based inverter model on rotor side is proposed with a view to improving the dynamic effects, controlling high torque producing and adjusting machine speed in instantaneous forced conditions. For the simulation model of the system in which the stator side is directly connected to the grid in steady state operation, a C/C++ algorithm is developed and the results obtained for different load conditions are discussed.

  3. Low-power grating detection system chip for high-speed low-cost length and angle precision measurement

    Science.gov (United States)

    Hou, Ligang; Luo, Rengui; Wu, Wuchen

    2006-11-01

    This paper forwards a low power grating detection chip (EYAS) on length and angle precision measurement. Traditional grating detection method, such as resister chain divide or phase locked divide circuit are difficult to design and tune. The need of an additional CPU for control and display makes these methods' implementation more complex and costly. Traditional methods also suffer low sampling speed for the complex divide circuit scheme and CPU software compensation. EYAS is an application specific integrated circuit (ASIC). It integrates micro controller unit (MCU), power management unit (PMU), LCD controller, Keyboard interface, grating detection unit and other peripherals. Working at 10MHz, EYAS can afford 5MHz internal sampling rate and can handle 1.25MHz orthogonal signal from grating sensor. With a simple control interface by keyboard, sensor parameter, data processing and system working mode can be configured. Two LCD controllers can adapt to dot array LCD or segment bit LCD, which comprised output interface. PMU alters system between working and standby mode by clock gating technique to save power. EYAS in test mode (system action are more frequently than real world use) consumes 0.9mw, while 0.2mw in real world use. EYAS achieved the whole grating detection system function, high-speed orthogonal signal handling in a single chip with very low power consumption.

  4. Experimental evaluation of the MIT-SNL period-generated minimum time control laws for the rapid adjustment of reactor power

    International Nuclear Information System (INIS)

    Bernard, J.A.; Kwok, K.S.; Menadier, P.T.; Thome, F.V.; Wyant, F.J.

    1987-01-01

    The rapid adjustment of reactor neutronic power has recently been achieved by developing control laws that determine the actuator mechanism velocity necessary to produce a specified reactor period. Designated as the 'MIT-SNL Period-Generated Minimum Time Control Laws,' these relations are closed-form expressions of general applicability. In particular, if there is no limitation on the available rate of change of reactivity, these laws can be used to achieve virtually any desired power profile including time optimal ones. The innovative aspect of these laws is that the rate of change of reactivity rather than the reactivity itself is used as the control signal. For example, relative to a time-optimal response, these laws function by altering the rate of change of reactivity so that the instantaneous period is stepped from infinity to its minimum allowed value, held at that value until the desired power level is attained, and then stepped back to infinity. The response is time-optimal because the power adjustment is continuously made at the maximum allowed rate

  5. Finding NEMO (novel electromaterial muscle oscillator): a polypyrrole powered robotic fish with real-time wireless speed and directional control

    International Nuclear Information System (INIS)

    McGovern, Scott; Alici, Gursel; Spinks, Geoffrey; Truong, Van-Tan

    2009-01-01

    This paper presents the development of an autonomously powered and controlled robotic fish that incorporates an active flexural joint tail fin, activated through conducting polymer actuators based on polypyrrole (PPy). The novel electromaterial muscle oscillator (NEMO) tail fin assembly on the fish could be controlled wirelessly in real time by varying the frequency and duty cycle of the voltage signal supplied to the PPy bending-type actuators. Directional control was achieved by altering the duty cycle of the voltage input to the NEMO tail fin, which shifted the axis of oscillation and enabled turning of the robotic fish. At low speeds, the robotic fish had a turning circle as small as 15 cm (or 1.1 body lengths) in radius. The highest speed of the fish robot was estimated to be approximately 33 mm s −1 (or 0.25 body lengths s −1 ) and was achieved with a flapping frequency of 0.6–0.8 Hz which also corresponded with the most hydrodynamically efficient mode for tail fin operation. This speed is approximately ten times faster than those for any previously reported artificial muscle based device that also offers real-time speed and directional control. This study contributes to previously published studies on bio-inspired functional devices, demonstrating that electroactive polymer actuators can be real alternatives to conventional means of actuation such as electric motors

  6. Finding NEMO (novel electromaterial muscle oscillator): a polypyrrole powered robotic fish with real-time wireless speed and directional control

    Science.gov (United States)

    McGovern, Scott; Alici, Gursel; Truong, Van-Tan; Spinks, Geoffrey

    2009-09-01

    This paper presents the development of an autonomously powered and controlled robotic fish that incorporates an active flexural joint tail fin, activated through conducting polymer actuators based on polypyrrole (PPy). The novel electromaterial muscle oscillator (NEMO) tail fin assembly on the fish could be controlled wirelessly in real time by varying the frequency and duty cycle of the voltage signal supplied to the PPy bending-type actuators. Directional control was achieved by altering the duty cycle of the voltage input to the NEMO tail fin, which shifted the axis of oscillation and enabled turning of the robotic fish. At low speeds, the robotic fish had a turning circle as small as 15 cm (or 1.1 body lengths) in radius. The highest speed of the fish robot was estimated to be approximately 33 mm s-1 (or 0.25 body lengths s-1) and was achieved with a flapping frequency of 0.6-0.8 Hz which also corresponded with the most hydrodynamically efficient mode for tail fin operation. This speed is approximately ten times faster than those for any previously reported artificial muscle based device that also offers real-time speed and directional control. This study contributes to previously published studies on bio-inspired functional devices, demonstrating that electroactive polymer actuators can be real alternatives to conventional means of actuation such as electric motors.

  7. Wind speed reductions by large-scale wind turbine deployments lower turbine efficiencies and set low wind power potentials

    Science.gov (United States)

    Miller, Lee; Kleidon, Axel

    2017-04-01

    Wind turbines generate electricity by removing kinetic energy from the atmosphere. Large numbers of wind turbines are likely to reduce wind speeds, which lowers estimates of electricity generation from what would be presumed from unaffected conditions. Here, we test how well wind power potentials that account for this effect can be estimated without explicitly simulating atmospheric dynamics. We first use simulations with an atmospheric general circulation model (GCM) that explicitly simulates the effects of wind turbines to derive wind power limits (GCM estimate), and compare them to a simple approach derived from the climatological conditions without turbines [vertical kinetic energy (VKE) estimate]. On land, we find strong agreement between the VKE and GCM estimates with respect to electricity generation rates (0.32 and 0.37 We m-2) and wind speed reductions by 42 and 44%. Over ocean, the GCM estimate is about twice the VKE estimate (0.59 and 0.29 We m-2) and yet with comparable wind speed reductions (50 and 42%). We then show that this bias can be corrected by modifying the downward momentum flux to the surface. Thus, large-scale limits to wind power can be derived from climatological conditions without explicitly simulating atmospheric dynamics. Consistent with the GCM simulations, the approach estimates that only comparatively few land areas are suitable to generate more than 1 We m-2 of electricity and that larger deployment scales are likely to reduce the expected electricity generation rate of each turbine. We conclude that these atmospheric effects are relevant for planning the future expansion of wind power.

  8. Active Power and Flux Control of a Self-Excited Induction Generator for a Variable-Speed Wind Turbine Generation

    Energy Technology Data Exchange (ETDEWEB)

    Na, Woonki; Muljadi, Eduard; Leighty, Bill; Kim, Jonghoon

    2017-05-11

    A Self-Excited Induction Generation (SEIG) for a variable speed wind turbine generation(VS-WG) is normally considered to be a good candidate for implementation in stand-alone applications such as battery charging, hydrogenation, water pumping, water purification, water desalination, and etc. In this study, we have examined a study on active power and flux control strategies for a SEIG for a variable speed wind turbine generation. The control analysis for the proposed system is carried out by using PSCAD software. In the process, we can optimize the control design of the system, thereby enhancing and expediting the control design procedure for this application. With this study, this control design for a SEIG for VS-WG can become the industry standard for analysis and development in terms of SEIG.

  9. Variable-Speed Power-Turbine for the Large Civil Tilt Rotor

    Science.gov (United States)

    Suchezky, Mark; Cruzen, G. Scott

    2012-01-01

    Turbine design concepts were studied for application to a large civil tiltrotor transport aircraft. The concepts addressed the need for high turbine efficiency across the broad 2:1 turbine operating speed range representative of the notional mission for the aircraft. The study focused on tailoring basic turbine aerodynamic design design parameters to avoid the need for complex, heavy, and expensive variable geometry features. The results of the study showed that good turbine performance can be achieved across the design speed range if the design focuses on tailoring the aerodynamics for good tolerance to large swings in incidence, as opposed to optimizing for best performance at the long range cruise design point. A rig design configuration and program plan are suggested for a dedicated experiment to validate the proposed approach.

  10. Variable-speed wind power system with improved energy capture via multilevel conversion

    Science.gov (United States)

    Erickson, Robert W.; Al-Naseem, Osama A.; Fingersh, Lee Jay

    2005-05-31

    A system and method for efficiently capturing electrical energy from a variable-speed generator are disclosed. The system includes a matrix converter using full-bridge, multilevel switch cells, in which semiconductor devices are clamped to a known constant DC voltage of a capacitor. The multilevel matrix converter is capable of generating multilevel voltage wave waveform of arbitrary magnitude and frequencies. The matrix converter can be controlled by using space vector modulation.

  11. An innovative medium speed wind turbine rotor blade design for low wind regime (electrical power generation)

    International Nuclear Information System (INIS)

    Abas Abd Wahab; Chong Wen Tong

    2001-01-01

    This paper describes the preliminary study of a small-scale wind turbine rotor blade (a low wind speed region turbine). A new wind turbine rotor blade (AE2 blade) for stand alone system has been conceptualized, designed, constructed and tested. The system is a reduced size prototype (half-scaled) to develop an efficient (adapted to Malaysian wind conditions)and cost effective wind energy conversion system (WECS) with local design and production technique. The blades were constructed from aluminium sheet with metal blending technique. The layout and design of rotor blade, its innovative features and test results are presented. Results from indoor test showed that the advantages of AE2 blade in low speed, with the potential of further improvements. The best rotor efficiency, C P attained with simple AE2 blades rotor (number of blade = 3) was 37.3% (Betz efficiency = 63%) at tip speed ratio (TSR) = 3.6. From the fabrication works and indoor testing, the AE2 blade rotor has demonstrated its structural integrity (ease of assembly and transportation), simplicity, acceptable performance and low noise level. (Author)

  12. FPGA Based Low Power Router Design Using High Speed Transeceiver Logic IO Standard

    DEFF Research Database (Denmark)

    Thind, Vandana; Hussain, Dil muhammed Akbar

    2015-01-01

    and information. Router is main component of computer networks is an intelligent device uses to transfer data packets between various computer networks. Router must consume low power to perform its work in an efficient manner. To achieve the same the work has been done to make a FPGA based low power design using...

  13. Supersonic plasma beams with controlled speed generated by the alternative low power hybrid ion engine (ALPHIE) for space propulsion

    Science.gov (United States)

    Conde, L.; Domenech-Garret, J. L.; Donoso, J. M.; Damba, J.; Tierno, S. P.; Alamillo-Gamboa, E.; Castillo, M. A.

    2017-12-01

    The characteristics of supersonic ion beams from the alternative low power hybrid ion engine (ALPHIE) are discussed. This simple concept of a DC powered plasma accelerator that only needs one electron source for both neutral gas ionization and ion beam neutralization is also examined. The plasma production and space charge neutralization processes are thus coupled in this plasma thruster that has a total DC power consumption of below 450 W, and uses xenon or argon gas as a propellant. The operation parameters of the plasma engine are studied in the laboratory in connection with the ion energy distribution function obtained with a retarding-field energy analyzer. The ALPHIE plasma beam expansion produces a mesothermal plasma flow with two-peaked ion energy distribution functions composed of low and high speed ion groups. The characteristic drift velocities of the fast ion groups, in the range 36.6-43.5 Km/s, are controlled by the acceleration voltage. These supersonic speeds are higher than the typical ion sound velocities of the low energy ion group produced by the expansion of the plasma jet. The temperatures of the slow ion population lead to ion Debye lengths longer than the electron Debye lengths. Furthermore, the electron impact ionization can coexist with collisional ionization by fast ions downstream the grids. Finally, the performance characteristics and comparisons with other plasma accelerator schemes are also discussed.

  14. Integrated Optimization of Speed Profiles and Power Split for a Tram with Hybrid Energy Storage Systems on a Signalized Route

    Directory of Open Access Journals (Sweden)

    Zhuang Xiao

    2018-02-01

    Full Text Available A tram with on-board hybrid energy storage systems based on batteries and supercapacitors is a new option for the urban traffic system. This configuration enables the tram to operate in both catenary zones and catenary-free zones, and the storage of regenerative braking energy for later usage. This paper presents a multiple phases integrated optimization (MPIO method for the coordination of speed profiles and power split considering the signal control strategy. The objective is to minimize the equivalent total energy consumption of all the power sources, which includes both the energy from the traction substation and energy storage systems. The constraints contain running time, variable gradients and curves, speed limits, power balance and signal time at some intersections. The integrated optimization problem is formulated as a multiple phases model based on the characters of the signalized route. An integrated calculation framework, using hp-adaptive pseudospectral method, is proposed for the integrated optimization problem. The effectiveness of the method is verified under fixed time signal (FTS control strategy and tram priority signal (TPS control strategy. Illustrative results show that this method can be successfully applied for trams with hybrid energy storage systems to improve their energy efficiency.

  15. Adaptative control with non-minimum phase system. Application to level control in PWR power plant steam generator

    International Nuclear Information System (INIS)

    Bihoreau, C.

    1981-03-01

    This thesis presents the proposal for a water control level method likely to improve performance, especially at low power. Particular problems are analyzed in detail. Finally, computerized simulations are presented; they confirm the algorithm performance [fr

  16. Alterations in speed of squat movement and the use of accommodated resistance among college athletes training for power.

    Science.gov (United States)

    Rhea, Matthew R; Kenn, Joseph G; Dermody, Bryan M

    2009-12-01

    The purpose of this study was to assess the effect of heavy/slow movements and variable resistance training on peak power and strength development. Forty-eight National Collegiate Athletic Association (NCAA) Division I athletes (age: 21.4 +/- 2.1 years, all men) were recruited for this 12-week training intervention study. Maximum strength and jumping power were assessed before and after the training program. Athletes were randomly assigned to 1 of 3 training groups: heavy resistance/slow movement (Slow), lighter resistance and fast movement (Fast), or fast movements with accommodated resistance (FACC). All training groups performed similar training programs comprising free weight resistance training with lower-body compound exercises. The only difference among the training interventions was the speed at which subjects performed the squat exercise and the use of bands (Slow group: 0.2-0.4 meters/second; Fast group: 0.6-0.8 meters/second; FACC group trained 0.6-0.8 meters/second with the addition of accommodated resistance in the form of large elastic bands). Post-test data revealed a significant difference between power improvements between the Slow and FACC groups (p = 0.02). Percent increases and effect sizes (ES) demonstrated a much greater treatment effect in the FACC group (17.8%, ES = 1.06) with the Fast group (11.0%, ES = 0.80) adapting more than the Slow group (4.8%, ES = 0.28). The FACC and Slow groups improved strength comparatively (FACC: 9.44%, ES = 1.10; Slow: 9.59%, ES = 1.08). The Fast group improved strength considerably less, 3.20% with an effect size of only 0.38. Variable resistance training with elastic bands appears to provide greater performance benefits with regard to peak force and peak power than heavy, slow resistance exercise. Sports conditioning professionals can utilize bands, and high-speed contractions, to increase power development.

  17. Analysis and Comparison of Modular Railway Power Conditioner for High-Speed Railway Traction System

    DEFF Research Database (Denmark)

    Xu, Qianming; Ma, Fujun; He, Zhixing

    2017-01-01

    , IPOSIM calculation as well as PSIM simulation. These calculations are validated via simulations results in PSIM. The main conclusion is that presented modular RPCs can be divided into general purpose RPC and special purpose RPC in terms of the behavior and efficiency. It is helpful to choose......, voltage stress and current stress of power switch, numbers of the power switches and capacitor are derived by analytical methods. Moreover, the numerical comparison of operating controllers is completed for modular RPCs. In addition, power losses of five modular RPCs are obtained by theoretical analysis...

  18. Variable Speed (DFIG) Wind Turbines: Rapid Frequency Response to Power System Disturbances

    DEFF Research Database (Denmark)

    Chandrashekhara, Divya K; Hansen, Anca Daniela; Sørensen, Poul Ejnar

    2009-01-01

    This paper examines the effect of integrating large number of wind turbines particularly the double fed induction generator (DFIG) on the virtual inertia of the Danish power system network. The virtual inertia refers to the kinetic energy stored in the rotating masses which can be released...... initially to counter act the frequency change during a power system disturbance. Simulation studies have been carried out on a generic reduced model of a transmission power grid of the Danish TSO Energinet.dk to assess the impact of loss of generation on system frequency. Further, simulation study has been...

  19. Rejoinder on: Space-time wind speed forecasting for improved power system dispatch

    KAUST Repository

    Zhu, Xinxin

    2014-02-27

    We are thankful to the four reviewers for providing very valuable and insightful comments. We have divided our rejoinder into two main parts: (1) the rotating RSTD model; and (2) the integration of wind power into a power system. In each part, we present our views on the various comments of the discussants and provide further discussion. © 2014 Sociedad de Estadística e Investigación Operativa.

  20. Rejoinder on: Space-time wind speed forecasting for improved power system dispatch

    KAUST Repository

    Zhu, Xinxin; Genton, Marc G.; Gu, Yingzhong; Xie, Le

    2014-01-01

    We are thankful to the four reviewers for providing very valuable and insightful comments. We have divided our rejoinder into two main parts: (1) the rotating RSTD model; and (2) the integration of wind power into a power system. In each part, we present our views on the various comments of the discussants and provide further discussion. © 2014 Sociedad de Estadística e Investigación Operativa.

  1. A power scalable PLL frequency synthesizer for high-speed Δ—Σ ADC

    International Nuclear Information System (INIS)

    Han Siyang; Chi Baoyong; Zhang Xinwang; Wang Zhihua

    2014-01-01

    A 35–130 MHz/300–360 MHz phase-locked loop frequency synthesizer for Δ—Σ analog-to-digital converter (ADC) in 65 nm CMOS is presented. The frequency synthesizer can work in low phase-noise mode (300–360 MHz) or in low-power mode (35–130 MHz) to satisfy the ADC's requirements. To switch between these two modes, a high frequency GHz LC VCO followed by a divided-by-four frequency divider and a low frequency ring VCO followed by a divided-by-two frequency divider are integrated on-chip. The measured results show that the frequency synthesizer achieves a phase-noise of −132 dBc/Hz at 1 MHz offset and an integrated RMS jitter of 1.12 ps with 1.74 mW power consumption from a 1.2 V power supply in low phase-noise mode. In low-power mode, the frequency synthesizer achieves a phase-noise of −112 dBc/Hz at 1 MHz offset and an integrated RMS jitter of 7.23 ps with 0.92 mW power consumption from a 1.2 V power supply. (semiconductor integrated circuits)

  2. Scandium doped Ge2Sb2Te5 for high-speed and low-power-consumption phase change memory

    Science.gov (United States)

    Wang, Yong; Zheng, Yonghui; Liu, Guangyu; Li, Tao; Guo, Tianqi; Cheng, Yan; Lv, Shilong; Song, Sannian; Ren, Kun; Song, Zhitang

    2018-03-01

    To bridge the gap of access time between memories and storage systems, the concept of storage class memory has been put forward based on emerging nonvolatile memory technologies. For all the nonvolatile memory candidates, the unpleasant tradeoff between operation speed and retention seems to be inevitable. To promote both the write speed and the retention of phase change memory (PCM), Sc doped Ge2Sb2Te5 (SGST) has been proposed as the storage medium. Octahedral Sc-Te motifs, acting as crystallization precursors to shorten the nucleation incubation period, are the possible reason for the high write speed of 6 ns in PCM cells, five-times faster than that of Ge2Sb2Te5 (GST) cells. Meanwhile, an enhanced 10-year data retention of 119 °C has been achieved. Benefiting from both the increased crystalline resistance and the inhibited formation of the hexagonal phase, the SGST cell has a 77% reduction in power consumption compared to the GST cell. Adhesion of the SGST/SiO2 interface has been strengthened, attributed to the reduced stress by forming smaller grains during crystallization, guaranteeing the reliability of the device. These improvements have made the SGST material a promising candidate for PCM application.

  3. High power CO2 laser development with AOM integration for ultra high-speed pulses

    Science.gov (United States)

    Bohrer, Markus; Vaupel, Matthias; Nirnberger, Robert; Weinberger, Bernhard; Jamalieh, Murad

    2017-01-01

    There is a 500 billion USD world market for packaging expected to grow to a trillion in 2030. Austria plays an important role world wide for high speed laser engraving applications — especially when it comes to high end solutions. Such high end solutions are fundamental for the production of print forms for the packaging and decorating industry (e. g. cans). They are additionally used for security applications (e. g. for printing banknotes), for the textile printing industry and for creating embossing forms (e. g. for the production of dashboards in the automotive industry). High speed, high precision laser engraving needs laser resonators with very stable laser beams (400 - 800W) especially in combination with AOMs. Based upon a unique carbon fiber structure - stable within the sub-micrometer range - a new resonator has been developed, accompanied by most recent thermo-mechanical FEM calculations. The resulting beam is evaluated on an automated optical bench using hexapods, allowing to optimize the complete beam path with collimators and AOM. The major steps related to laser engraving of dry offset printing plates during the full workflow from the artists design to the printed result on an aluminum can is presented in this paper as well as laser characteristics, AOM integration and correlative CLSM and SEM investigation of the results.

  4. Effectiveness of Traditional Strength vs. Power Training on Muscle Strength, Power and Speed with Youth: A Systematic Review and Meta-Analysis

    Science.gov (United States)

    Behm, David G.; Young, James D.; Whitten, Joseph H. D.; Reid, Jonathan C.; Quigley, Patrick J.; Low, Jonathan; Li, Yimeng; Lima, Camila D.; Hodgson, Daniel D.; Chaouachi, Anis; Prieske, Olaf; Granacher, Urs

    2017-01-01

    Numerous national associations and multiple reviews have documented the safety and efficacy of strength training for children and adolescents. The literature highlights the significant training-induced increases in strength associated with youth strength training. However, the effectiveness of youth strength training programs to improve power measures is not as clear. This discrepancy may be related to training and testing specificity. Most prior youth strength training programs emphasized lower intensity resistance with relatively slow movements. Since power activities typically involve higher intensity, explosive-like contractions with higher angular velocities (e.g., plyometrics), there is a conflict between the training medium and testing measures. This meta-analysis compared strength (e.g., training with resistance or body mass) and power training programs (e.g., plyometric training) on proxies of muscle strength, power, and speed. A systematic literature search using a Boolean Search Strategy was conducted in the electronic databases PubMed, SPORT Discus, Web of Science, and Google Scholar and revealed 652 hits. After perusal of title, abstract, and full text, 107 studies were eligible for inclusion in this systematic review and meta-analysis. The meta-analysis showed small to moderate magnitude changes for training specificity with jump measures. In other words, power training was more effective than strength training for improving youth jump height. For sprint measures, strength training was more effective than power training with youth. Furthermore, strength training exhibited consistently large magnitude changes to lower body strength measures, which contrasted with the generally trivial, small and moderate magnitude training improvements of power training upon lower body strength, sprint and jump measures, respectively. Maturity related inadequacies in eccentric strength and balance might influence the lack of training specificity with the unilateral

  5. Effectiveness of Traditional Strength vs. Power Training on Muscle Strength, Power and Speed with Youth: A Systematic Review and Meta-Analysis

    Directory of Open Access Journals (Sweden)

    David G. Behm

    2017-06-01

    Full Text Available Numerous national associations and multiple reviews have documented the safety and efficacy of strength training for children and adolescents. The literature highlights the significant training-induced increases in strength associated with youth strength training. However, the effectiveness of youth strength training programs to improve power measures is not as clear. This discrepancy may be related to training and testing specificity. Most prior youth strength training programs emphasized lower intensity resistance with relatively slow movements. Since power activities typically involve higher intensity, explosive-like contractions with higher angular velocities (e.g., plyometrics, there is a conflict between the training medium and testing measures. This meta-analysis compared strength (e.g., training with resistance or body mass and power training programs (e.g., plyometric training on proxies of muscle strength, power, and speed. A systematic literature search using a Boolean Search Strategy was conducted in the electronic databases PubMed, SPORT Discus, Web of Science, and Google Scholar and revealed 652 hits. After perusal of title, abstract, and full text, 107 studies were eligible for inclusion in this systematic review and meta-analysis. The meta-analysis showed small to moderate magnitude changes for training specificity with jump measures. In other words, power training was more effective than strength training for improving youth jump height. For sprint measures, strength training was more effective than power training with youth. Furthermore, strength training exhibited consistently large magnitude changes to lower body strength measures, which contrasted with the generally trivial, small and moderate magnitude training improvements of power training upon lower body strength, sprint and jump measures, respectively. Maturity related inadequacies in eccentric strength and balance might influence the lack of training specificity with

  6. Relationship Between Change of Direction, Speed and Power in Male and Female National Olympic Team Handball Athletes.

    Science.gov (United States)

    Pereira, Lucas A; Nimphius, Sophia; Kobal, Ronaldo; Kitamura, Katia; Turisco, Luiz A L; Orsi, Rita C; Cal Abad, César Cs; Loturco, Irineu

    2018-02-22

    The aims of this study were to (1) assess the relationship between selected speed-power related abilities (determined by 20-m sprint, unloaded countermovement and squat jumps [CMJ and SJ] and loaded jump squat [JS]) and performance in two distinct change of direction (COD) protocols (Zigzag and T-Test), and (2) determine the magnitude of difference between female and male Brazilian National Olympic Team handball athletes. Fifteen male and twenty-three female elite handball athletes volunteered to perform the following assessments: SJ and CMJ; Zigzag and T-Test; 20-m sprint with 5-, 10-, and 20-m splits, and mean propulsive power (MPP) in JS. Pearson product moment correlation (Phandball athletes.

  7. Area, speed and power measurements of FPGA-based complex orthogonal space-time block code channel encoders

    Science.gov (United States)

    Passas, Georgios; Freear, Steven; Fawcett, Darren

    2010-01-01

    Space-time coding (STC) is an important milestone in modern wireless communications. In this technique, more copies of the same signal are transmitted through different antennas (space) and different symbol periods (time), to improve the robustness of a wireless system by increasing its diversity gain. STCs are channel coding algorithms that can be readily implemented on a field programmable gate array (FPGA) device. This work provides some figures for the amount of required FPGA hardware resources, the speed that the algorithms can operate and the power consumption requirements of a space-time block code (STBC) encoder. Seven encoder very high-speed integrated circuit hardware description language (VHDL) designs have been coded, synthesised and tested. Each design realises a complex orthogonal space-time block code with a different transmission matrix. All VHDL designs are parameterisable in terms of sample precision. Precisions ranging from 4 bits to 32 bits have been synthesised. Alamouti's STBC encoder design [Alamouti, S.M. (1998), 'A Simple Transmit Diversity Technique for Wireless Communications', IEEE Journal on Selected Areas in Communications, 16:55-108.] proved to be the best trade-off, since it is on average 3.2 times smaller, 1.5 times faster and requires slightly less power than the next best trade-off in the comparison, which is a 3/4-rate full-diversity 3Tx-antenna STBC.

  8. Transmit Power Minimization and Base Station Planning for High-Speed Trains with Multiple Moving Relays in OFDMA Systems

    KAUST Repository

    Ghazzai, Hakim

    2016-03-15

    High-speed railway system equipped with moving relay stations placed on the middle of the ceiling of each train wagon is investigated. The users inside the train are served in two hops via the orthogonal frequency-division multiple access (OFDMA) technology. In this work, we first focus on minimizing the total downlink power consumption of the base station (BS) and the moving relays while respecting specific quality of service (QoS) constraints. We first derive the optimal resource allocation solution in terms of OFDMA subcarriers and power allocation using the dual decomposition method. Then, we propose an efficient algorithm based on the Hungarian method in order to find a suboptimal but low complexity solution. Moreover, we propose an OFDMA planning solution for high-speed train by finding the maximal inter-BS distance given the required user data rates in order to perform seamless handover. Our simulation results illustrate the performance of the proposed resource allocation schemes in the case of the 3GPP Long Term Evolution-Advanced (LTE-A) and compare them with previously developed algorithms as well as with the direct transmission scenario. Our results also highlight the significant planning gain obtained thanks to the use of multiple relays instead of the conventional single relay scenario.

  9. Power maximization of variable-speed variable-pitch wind turbines using passive adaptive neural fault tolerant control

    Science.gov (United States)

    Habibi, Hamed; Rahimi Nohooji, Hamed; Howard, Ian

    2017-09-01

    Power maximization has always been a practical consideration in wind turbines. The question of how to address optimal power capture, especially when the system dynamics are nonlinear and the actuators are subject to unknown faults, is significant. This paper studies the control methodology for variable-speed variable-pitch wind turbines including the effects of uncertain nonlinear dynamics, system fault uncertainties, and unknown external disturbances. The nonlinear model of the wind turbine is presented, and the problem of maximizing extracted energy is formulated by designing the optimal desired states. With the known system, a model-based nonlinear controller is designed; then, to handle uncertainties, the unknown nonlinearities of the wind turbine are estimated by utilizing radial basis function neural networks. The adaptive neural fault tolerant control is designed passively to be robust on model uncertainties, disturbances including wind speed and model noises, and completely unknown actuator faults including generator torque and pitch actuator torque. The Lyapunov direct method is employed to prove that the closed-loop system is uniformly bounded. Simulation studies are performed to verify the effectiveness of the proposed method.

  10. Complementary Aerodynamic Performance Datasets for Variable Speed Power Turbine Blade Section from Two Independent Transonic Turbine Cascades

    Science.gov (United States)

    Flegel, Ashlie B.; Welch, Gerard E.; Giel, Paul W.; Ames, Forrest E.; Long, Jonathon A.

    2015-01-01

    Two independent experimental studies were conducted in linear cascades on a scaled, two-dimensional mid-span section of a representative Variable Speed Power Turbine (VSPT) blade. The purpose of these studies was to assess the aerodynamic performance of the VSPT blade over large Reynolds number and incidence angle ranges. The influence of inlet turbulence intensity was also investigated. The tests were carried out in the NASA Glenn Research Center Transonic Turbine Blade Cascade Facility and at the University of North Dakota (UND) High Speed Compressible Flow Wind Tunnel Facility. A large database was developed by acquiring total pressure and exit angle surveys and blade loading data for ten incidence angles ranging from +15.8deg to -51.0deg. Data were acquired over six flow conditions with exit isentropic Reynolds number ranging from 0.05×106 to 2.12×106 and at exit Mach numbers of 0.72 (design) and 0.35. Flow conditions were examined within the respective facility constraints. The survey data were integrated to determine average exit total-pressure and flow angle. UND also acquired blade surface heat transfer data at two flow conditions across the entire incidence angle range aimed at quantifying transitional flow behavior on the blade. Comparisons of the aerodynamic datasets were made for three "match point" conditions. The blade loading data at the match point conditions show good agreement between the facilities. This report shows comparisons of other data and highlights the unique contributions of the two facilities. The datasets are being used to advance understanding of the aerodynamic challenges associated with maintaining efficient power turbine operation over a wide shaft-speed range.

  11. Development of High-Speed Switched Reluctance Motor for Electric Power Tools

    Science.gov (United States)

    Nakamura, Kenji; Kumasaka, Yuya; Ichinokura, Osamu

    2017-10-01

    This paper presents design and experimental evaluation of a switched reluctance (SR) motor used for electric power tools. First, characteristics of a previous designed 6/4-pole SR motor is shown and compared to a permanent magnet (PM) motor used in present electric power tools. Next, to further improve characteristics, a 12/8-pole SR motor is designed and evaluated in experiment. It is proved that the performance of the prototype 12/8-pole SR motor is almost comparable or superior to the present PM motor.

  12. Extending the Constant Power Speed Range of the Brushless DC Motor through Dual Mode Inverter Control -- Part I: Theory and Simulation

    International Nuclear Information System (INIS)

    Lawler, J.S.

    2001-01-01

    An inverter topology and control scheme has been developed that can drive low-inductance, surface-mounted permanent magnet motors over the wide constant power speed range required in electric vehicle applications. This new controller is called the dual-mode inverter control (DMIC)[1]. The DMIC can drive either the Permanent Magnet Synchronous Machine (PMSM) with sinusoidal back emf, or the brushless dc machine (BDCM) with trapezoidal emf in the motoring and regenerative braking modes. In this paper we concentrate on the BDCM under high-speed motoring conditions. Simulation results show that if all motor and inverter loss mechanisms are neglected, the constant power speed range of the DMIC is infinite. The simulation results are supported by closed form expressions for peak and rms motor current and average power derived from analytical solution to the differential equations governing the DMIC/BDCM drive for the lossless case. The analytical solution shows that the range of motor inductance that can be accommodated by the DMIC is more than an order of magnitude such that the DMIC is compatible with both low- and high-inductance BDCMs. Finally, method is given for integrating the classical hysteresis band current control, used for motor control below base speed, with the phase advance of DMIC that is applied above base speed. The power versus speed performance of the DMIC is then simulated across the entire speed range

  13. High-efficiency space-based software radio architectures & algorithms (a minimum size, weight, and power TeraOps processor)

    Energy Technology Data Exchange (ETDEWEB)

    Dunham, Mark Edward [Los Alamos National Laboratory; Baker, Zachary K [Los Alamos National Laboratory; Stettler, Matthew W [Los Alamos National Laboratory; Pigue, Michael J [Los Alamos National Laboratory; Schmierer, Eric N [Los Alamos National Laboratory; Power, John F [Los Alamos National Laboratory; Graham, Paul S [Los Alamos National Laboratory

    2009-01-01

    Los Alamos has recently completed the latest in a series of Reconfigurable Software Radios, which incorporates several key innovations in both hardware design and algorithms. Due to our focus on satellite applications, each design must extract the best size, weight, and power performance possible from the ensemble of Commodity Off-the-Shelf (COTS) parts available at the time of design. In this case we have achieved 1 TeraOps/second signal processing on a 1920 Megabit/second datastream, while using only 53 Watts mains power, 5.5 kg, and 3 liters. This processing capability enables very advanced algorithms such as our wideband RF compression scheme to operate remotely, allowing network bandwidth constrained applications to deliver previously unattainable performance.

  14. High speed low power optical detection of sub-wavelength scatterer

    NARCIS (Netherlands)

    Roy, S.; Bouwens, M.A.J.; Wei, L.; Pereira, S.F.; Urbach, H.P.; Walle, P. van der

    2015-01-01

    Optical detection of scatterers on a flat substrate, generally done using dark field microscopy technique, is challenging since it requires high power illumination to obtain sufficient SNR (Signal to Noise Ratio) to be able to detect sub-wavelength particles. We developed a bright field technique,

  15. Space-time wind speed forecasting for improved power system dispatch

    KAUST Repository

    Zhu, Xinxin; Genton, Marc G.; Gu, Yingzhong; Xie, Le

    2014-01-01

    direction and with the seasons, hence avoiding a subjective choice of regimes. Then, results from the wind forecasts are incorporated into a power system economic dispatch model, the cost of which is used as a loss measure of the quality of the forecast

  16. A novel match-line selective charging scheme for high-speed, low-power and noise-tolerant content-addressable memory

    KAUST Repository

    Hasan, Muhammad Mubashwar; Rashid, Abdul B M Harun Ur; Hussain, Muhammad Mustafa

    2010-01-01

    Content-addressable memory (CAM) is an essential component for high-speed lookup intensive applications. This paper presents a match-line selective charging technique to increase speed and reduce the energy per bit per search while increasing the noise-tolerance. Simulation in TSMC 0.18 μm technology with 64×72 Ternary CAM shows the match-line energy reduction of 45% compared to the conventional currentsaving scheme with the reduction of minimum cycle time by 68% and the improvement of noise-tolerance by 96%.

  17. A novel match-line selective charging scheme for high-speed, low-power and noise-tolerant content-addressable memory

    KAUST Repository

    Hasan, Muhammad Mubashwar

    2010-06-01

    Content-addressable memory (CAM) is an essential component for high-speed lookup intensive applications. This paper presents a match-line selective charging technique to increase speed and reduce the energy per bit per search while increasing the noise-tolerance. Simulation in TSMC 0.18 μm technology with 64×72 Ternary CAM shows the match-line energy reduction of 45% compared to the conventional currentsaving scheme with the reduction of minimum cycle time by 68% and the improvement of noise-tolerance by 96%.

  18. The solar and interplanetary causes of the recent minimum in geomagnetic activity (MGA23: a combination of midlatitude small coronal holes, low IMF BZ variances, low solar wind speeds and low solar magnetic fields

    Directory of Open Access Journals (Sweden)

    B. T. Tsurutani

    2011-05-01

    Full Text Available Minima in geomagnetic activity (MGA at Earth at the ends of SC23 and SC22 have been identified. The two MGAs (called MGA23 and MGA22, respectively were present in 2009 and 1997, delayed from the sunspot number minima in 2008 and 1996 by ~1/2–1 years. Part of the solar and interplanetary causes of the MGAs were exceptionally low solar (and thus low interplanetary magnetic fields. Another important factor in MGA23 was the disappearance of equatorial and low latitude coronal holes and the appearance of midlatitude coronal holes. The location of the holes relative to the ecliptic plane led to low solar wind speeds and low IMF (Bz variances (σBz2 and normalized variances (σBz2/B02 at Earth, with concomitant reduced solar wind-magnetospheric energy coupling. One result was the lowest ap indices in the history of ap recording. The results presented here are used to comment on the possible solar and interplanetary causes of the low geomagnetic activity that occurred during the Maunder Minimum.

  19. Effect of 8 days of a hypergravity condition on the sprinting speed and lower-body power of elite rugby players.

    Science.gov (United States)

    Barr, Matthew J; Gabbett, Tim J; Newton, Robert U; Sheppard, Jeremy M

    2015-03-01

    -Sprinting speed and lower-body power are considered to be key physical abilities for rugby players. A method of improving the lower-body power of athletes is simulated hypergravity. This method involves wearing a weighted vest at all times during the day for an extended period of time. There are no studies that have examined the effect of hypergravity on speed or the benefit for rugby players. An experimental group (n = 8) and a control group (n = 7) of national team rugby players took part in the study, which consisted of rugby, conditioning, speed, and strength sessions. The experimental group wore a weighted vest equating to 12% of their body mass for 8 days. All players were tested for speed and lower-body power before, 2 days after, and 9 days after the intervention. Speed testing involved the athletes completing 40-m sprints with timing lights and high-speed video cameras assessing acceleration and maximal velocity sprinting kinematics. Lower-body power was assessed using weighted countermovement jumps (CMJs). No group differences were found for sprinting speed at any point. The experimental group displayed a large decrease in acceleration ground contact time (-0.01 ± 0.005 s, d = 1.07) and a moderate increase in 15-kg CMJ velocity (0.07 ± 0.11 m·s, d = 0.71). Individual responses showed that players in the experimental group had both negative and positive speed and power responses to the training intervention. Simulated hypergravity for 8 days is likely ineffective at improving sprinting speed while undergoing standard rugby training.

  20. From power plant to people at the light speed: electrical wires and development

    Directory of Open Access Journals (Sweden)

    Gildo Magalhães dos Santos Filho

    2015-03-01

    Full Text Available The Electromemory Project focuses on the history of electrification of São Paulo state from 1890 to 2005. Its first phase ran between 2007-10, studying the power plants, the archives, and the material culture of the following corporations: CESP (rivers Paraná, Grande, Paraíba do Sul, AES-Tietê (Tietê river, Duke Energy (Paranapanema river, as well as the substations belonging to ISA-CTEEP in the state and to AES-Eletropaulo in the Greater São Paulo area. The second phase started in 2013, and encompasses the power plants owned by EMAE, CPFL, and a number of small concessionaries, built between 1890 and 1960. The author also presents the research areas of the Project – history of technology, industrial heritage, museology, geography, archivology, and library science – and then sketches a brief overview of the process.

  1. Fuzzy logic speed control for the engine of an air-powered vehicle

    OpenAIRE

    Qihui Yu; Yan Shi; Maolin Cai; Weiqing Xu

    2016-01-01

    To improve the condition of air and eliminate exhaust gas pollution, this article proposes a compressed air power system. Instead of an internal combustion engine, the automobile is equipped with a compressed air engine, which transforms the energy of compressed air into mechanical motion energy. A prototype was built, and the compressed air engine was tested on an experimental platform. The output torque and energy efficiency were obtained from experimental results. When the supply pressure ...

  2. Solid Waste from Four-stroke Medium Speed Engine Power Plant Operation

    OpenAIRE

    Smart, Heidi

    2016-01-01

    This thesis is a study of the solid-state waste generated in power plants based on internal combustion engine (ICE) technology, supplied by the Wärtsilä Energy Solutions division. This thesis, which characterizes and quantifies the waste, was done to enhance the ability of supporting customers in issues related to social and environmental impact assessment, environmental permits, waste management planning, etc. The Performance Standards on Environmental and Social Sustainability and the E...

  3. High-speed DNA-based rolling motors powered by RNase H

    Science.gov (United States)

    Yehl, Kevin; Mugler, Andrew; Vivek, Skanda; Liu, Yang; Zhang, Yun; Fan, Mengzhen; Weeks, Eric R.

    2016-01-01

    DNA-based machines that walk by converting chemical energy into controlled motion could be of use in applications such as next generation sensors, drug delivery platforms, and biological computing. Despite their exquisite programmability, DNA-based walkers are, however, challenging to work with due to their low fidelity and slow rates (~1 nm/min). Here, we report DNA-based machines that roll rather than walk, and consequently have a maximum speed and processivity that is three-orders of magnitude greater than conventional DNA motors. The motors are made from DNA-coated spherical particles that hybridise to a surface modified with complementary RNA; motion is achieved through the addition of RNase H, which selectively hydrolyses hybridised RNA. Spherical motors move in a self-avoiding manner, whereas anisotropic particles, such as dimerised particles or rod-shaped particles travel linearly without a track or external force. Finally, we demonstrate detection of single nucleotide polymorphism by measuring particle displacement using a smartphone camera. PMID:26619152

  4. Instantaneous power control of a high speed permanent magnet synchronous generator based on a sliding mode observer and a phase locked loop

    Science.gov (United States)

    Duan, Jiandong; Fan, Shaogui; Wu, Fengjiang; Sun, Li; Wang, Guanglin

    2018-06-01

    This paper proposes an instantaneous power control method for high speed permanent magnet synchronous generators (PMSG), to realize the decoupled control of active power and reactive power, through vector control based on a sliding mode observer (SMO), and a phase locked loop (PLL). Consequently, the high speed PMSG has a high internal power factor, to ensure efficient operation. Vector control and accurate estimation of the instantaneous power require an accurate estimate of the rotor position. The SMO is able to estimate the back electromotive force (EMF). The rotor position and speed can be obtained using a combination of the PLL technique and the phase compensation method. This method has the advantages of robust operation, and being resistant to noise when estimating the position of the rotor. Using instantaneous power theory, the relationship between the output active power, reactive power, and stator current of the PMSG is deduced, and the power constraint condition is analysed for operation at the unit internal power factor. Finally, the accuracy of the rotor position detection, the instantaneous power detection, and the control methods are verified using simulations and experiments.

  5. A new architecture for low-power high-speed pipelined ADCs using double-sampling and opamp-sharing techniques

    NARCIS (Netherlands)

    Abdinia, S.; Yavari, M.

    2009-01-01

    This paper presents a low-voltage low-power pipelined ADC with 1V supply voltage in a 90nm CMOS process. A new architecture is proposed to reduce the power consumption in high-speed pipelined analog-to-digital converters (ADCs). The presented architecture utilizes a combination of two current

  6. Assessment of wind speed and wind power through three stations in Egypt, including air density variation and analysis results with rough set theory

    International Nuclear Information System (INIS)

    Essa, K.S.M.; Embaby, M.; Marrouf, A.A.; Koza, A.M.; Abd El-Monsef, M.E.

    2007-01-01

    It is well known that the wind energy potential is proportional to both air density and the third power of the wind speed average over a suitable time period. The wind speed and air density have random variables depending on both time and location. The main objective of this work is to derive the most general wind energy potential of the wind formulation putting into consideration the time variable in both wind speed and air density. The correction factor is derived explicitly in terms of the cross-correlation and the coefficients of variation.The application is performed for environmental and wind speed measurements at the Cairo Airport, Kosseir and Hurguada, Egypt. Comparisons are made between Weibull, Rayleigh, and actual data distributions of wind speed and wind power of one year 2005. A Weibull distribution is the best match to the actual probability distribution of wind speed data for most stations. The maximum wind energy potential was 373 W/m 2 in June at Hurguada (Red Sea coast) where the annual mean value was 207 W/m 2 . By Using Rough Set Theory, We Find That the Wind Power Depends on the Wind Speed with greater than air density

  7. Ecologically justified regulatory provisions for riverine hydroelectric power plants and minimum instream flow requirements in diverted streams; Oekologisch begruendete, dynamische Mindestwasserregelungen bei Ausleitungskraftwerken

    Energy Technology Data Exchange (ETDEWEB)

    Jorde, K.

    1997-12-31

    The study was intended to develop a model versatile enough to permit quantification of various water demand scenarios in connection with operation of riverine hydroelectric power plants. Specific emphasis was to be placed on defining the minimum instream flow to be maintained in river segments because of the elementary significance to flowing water biocinoses. Based on fictitious minimum water requirements, various scenarious were simulated for flow regimes depending on power plant operation, so as to establish a system for comparative analysis and evaluation of resulting economic effects on power plant efficiency on the one hand, and the ecologic effects on the aquatic habitat. The information derived was to serve as a basis for decision-making for regulatory purposes. For this study, the temporal and spatial variability of the flow regime at the river bed in a river segment was examined for the first time. Based on this information, complemented by information obtained from habitat simulations, a method was derived for determination of ecologic requirements and their incorporation into regulatory water management provisions. The field measurements were carried out with the FST hemisphere as a proven and most efficient and reliable method of assessing flow regimes at river beds. Evaluation of the measured instream flow data characterising three morphologically different segments of diverted rivers was done with the CASIMIR computer code. The ASS models derived were used for comparative assessment of existing regulatory provisions and recommended amendments determining required minimum instream flow in diverted rivers. The requirements were defined taking as a basis data obtained for three different years. (orig./CB) [Deutsch] Ziel der Arbeit war die Entwicklung eines Modellverfahrens, das flexibel die Quantifizierung unterschiedlicher Nutzansprueche an Laufwasserkraftanlagen ermoeglicht. Insbesondere der Erhalt einer gewissen Dynamik, die fuer

  8. Ecologically justified regulatory provisions for riverine hydroelectric power plants and minimum instream flow requirements in diverted streams; Oekologisch begruendete, dynamische Mindestwasserregelungen bei Ausleitungskraftwerken

    Energy Technology Data Exchange (ETDEWEB)

    Jorde, K

    1998-12-31

    The study was intended to develop a model versatile enough to permit quantification of various water demand scenarios in connection with operation of riverine hydroelectric power plants. Specific emphasis was to be placed on defining the minimum instream flow to be maintained in river segments because of the elementary significance to flowing water biocinoses. Based on fictitious minimum water requirements, various scenarious were simulated for flow regimes depending on power plant operation, so as to establish a system for comparative analysis and evaluation of resulting economic effects on power plant efficiency on the one hand, and the ecologic effects on the aquatic habitat. The information derived was to serve as a basis for decision-making for regulatory purposes. For this study, the temporal and spatial variability of the flow regime at the river bed in a river segment was examined for the first time. Based on this information, complemented by information obtained from habitat simulations, a method was derived for determination of ecologic requirements and their incorporation into regulatory water management provisions. The field measurements were carried out with the FST hemisphere as a proven and most efficient and reliable method of assessing flow regimes at river beds. Evaluation of the measured instream flow data characterising three morphologically different segments of diverted rivers was done with the CASIMIR computer code. The ASS models derived were used for comparative assessment of existing regulatory provisions and recommended amendments determining required minimum instream flow in diverted rivers. The requirements were defined taking as a basis data obtained for three different years. (orig./CB) [Deutsch] Ziel der Arbeit war die Entwicklung eines Modellverfahrens, das flexibel die Quantifizierung unterschiedlicher Nutzansprueche an Laufwasserkraftanlagen ermoeglicht. Insbesondere der Erhalt einer gewissen Dynamik, die fuer

  9. THE EFFECTS OF COLD WHIRLPOOL ON POWER, SPEED, AGILITY, AND RANGE OF MOTION

    Directory of Open Access Journals (Sweden)

    Stephen M. Patterson

    2008-09-01

    Full Text Available The purpose was to determine if cold whirlpool treatment decreases functional performance equally regardless of gender. A secondary aim was to determine if there is a gradual increase in functional performance across time. Twenty-one college-aged subjects volunteered to participate in this study and were required to perform four measures of functional performance including: counter movement vertical jump, T-test, 36.58-meter dash (40-yard, and active range of motion of the ankle. Participants were treated with a 20 minute, 10 degree Celsius cold whirlpool following the pre-test of a given functional performance measure. Participants demonstrated significant decreases in counter movement vertical jump, T-test, and 40-yard dash performance immediately following treatment. Vertical jump performance remained impaired for at least 32 minutes. While both the T-test and 40-yard dash were affected for 7 and 22 minutes post- treatment, respectively. Participants also demonstrated significant decreases in peak power and average power immediately after and for 32 minutes post-treatment. Dorsiflexion was significantly decreased 7 and 12 minutes following treatment. There were no differences for plantar flexion, inversion, or eversion. These data suggest functional performance was affected immediately following and for up to 32 minutes after cold whirlpool treatment. It was also evident that there is a gradual performance increase for each measure of functional performance across time. Therefore, the consequences should be carefully considered before returning athletes to activity following cold whirlpool treatment

  10. Conducted Interference Immunity Characteristics to High-speed Power Line Communication System

    Science.gov (United States)

    Tokuda, Masamitsu; Hosoya, Satoshi; Yamagata, Toru; Matsuo, Takashi

    In this paper, we measured the immunity characteristics to the conducted interference wave, from the aspect of PHY rate (physical layer data rate) of PLC (Power Line Communication) system, and compared with simulation results by MATLAB/ Simulink. When the interference signal is impressed to the OFDM (Orthogonal Frequency Division Multiplexing) signal, the PHY rate decrease rapidly below C/I (Carrier / Interference) = 25dB and become nearly zero around C/I = -35dB, and so it turns out that the PLC System with OFDM signal has a good narrowband interference immunity characteristic. In addition, it is revealed that the PHY rate of PLC modem can be calculated by MATLAB/Simulink even when the narrowband interference signal is impressed through the power line. Furthermore, we examined the improving effect of the notch band for the immunity characteristics to the conducted interference wave. As a result, it is revealed that the PHY rate normalized by the maximum value increases by 15∼25% by inserting the notch when impressing the interference signal in the notch band and C/I is improved by 10∼15dB by inserting the notch.

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

    Science.gov (United States)

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

    2013-05-01

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

  12. Power Extraction Control of Variable Speed Wind Turbine Systems Based on Direct Drive Synchronous Generator in All Operating Regimes

    Directory of Open Access Journals (Sweden)

    Youssef Errami

    2018-01-01

    Full Text Available Due to the increased penetration of wind energy into the electrical power systems in recent years, the turbine controls are actively occupied in the research. This paper presents a nonlinear backstepping strategy to control the generators and the grid sides of a Wind Farm System (WFS based Direct Drive Synchronous Generator (DDSG. The control objectives such as Tracking the Maximum Power (TMP from the WFS, pitch control, regulation of dc-link voltage, and reactive and active power generation at varying wind velocity are included. To validate the proposed control strategy, simulation results for 6-MW-DDSG based Wind Farm System are carried out by MATLAB-Simulink. Performance comparison and evaluation with Vector Oriented Control (VOC are provided under a wide range of functioning conditions, three-phase voltage dips, and the probable occurrence of uncertainties. The proposed control strategy offers remarkable characteristics such as excellent dynamic and steady state performance under varying wind speed and robustness to parametric variations in the WFS and under severe faults of grid voltage.

  13. A novel power-efficient high-speed clock management unit using quantum-dot cellular automata

    International Nuclear Information System (INIS)

    Abutaleb, M. M.

    2017-01-01

    Quantum-dot cellular automata (QCA) is one of the most attractive alternatives for complementary metal-oxide semiconductor technology. The QCA widely supports a new paradigm in the field of nanotechnology that has the potential for high density, low power, and high speed. The clock manager is an essential building block in the new microwave and radio frequency integrated circuits. This paper describes a novel QCA-based clock management unit (CMU) that provides innovative clocking capabilities. The proposed CMU is achieved by utilizing edge-triggered D-type flip-flops (D-FFs) in the design of frequency synthesizer and phase splitter. Edge-triggered D-FF structures proposed in this paper have the successful QCA implementation and simulation with the least complexity and power dissipation as compared to earlier structures. The frequency synthesizer is used to generate new clock frequencies from the reference clock frequency based on a combination of power-of-two frequency dividers. The phase splitter is integrated with the frequency synthesizer to generate four clock signals that are 90"o out of phase with each other. This paper demonstrates that the proposed QCA CMU structure has a superior performance. Furthermore, the proposed CMU is straightforwardly scalable due to the use of modular component architecture.

  14. A novel power-efficient high-speed clock management unit using quantum-dot cellular automata

    Energy Technology Data Exchange (ETDEWEB)

    Abutaleb, M. M., E-mail: mustafa-abotaleb@h-eng.helwan.edu.eg [Helwan University, Department of Electronics, Communications and Computer Engineering (Egypt)

    2017-04-15

    Quantum-dot cellular automata (QCA) is one of the most attractive alternatives for complementary metal-oxide semiconductor technology. The QCA widely supports a new paradigm in the field of nanotechnology that has the potential for high density, low power, and high speed. The clock manager is an essential building block in the new microwave and radio frequency integrated circuits. This paper describes a novel QCA-based clock management unit (CMU) that provides innovative clocking capabilities. The proposed CMU is achieved by utilizing edge-triggered D-type flip-flops (D-FFs) in the design of frequency synthesizer and phase splitter. Edge-triggered D-FF structures proposed in this paper have the successful QCA implementation and simulation with the least complexity and power dissipation as compared to earlier structures. The frequency synthesizer is used to generate new clock frequencies from the reference clock frequency based on a combination of power-of-two frequency dividers. The phase splitter is integrated with the frequency synthesizer to generate four clock signals that are 90{sup o} out of phase with each other. This paper demonstrates that the proposed QCA CMU structure has a superior performance. Furthermore, the proposed CMU is straightforwardly scalable due to the use of modular component architecture.

  15. A High-Speed Power-Line Communication System with Band-Limited OQAM Based Multi-Carrier Transmission

    Science.gov (United States)

    Kawabata, Naohiro; Koga, Hisao; Muta, Osamu; Akaiwa, Yoshihiko

    As a method to realize a high-speed communication in the home network, the power-line communication (PLC) technique is known. A problem of PLC is that leakage radiation interferes with existing systems. When OFDM is used in a PLC system, the leakage radiation is not sufficiently reduced, even if the subcarriers corresponding to the frequency-band of the existing system are never used, because the signal is not strictly band-limited. To solve this problem, each subcarrier must be band-limited. In this paper, we apply the OQAM based multi-carrier transmission (OQAM-MCT) to a high-speed PLC system, where each subcarrier is individually band-limited. We also propose a pilot-symbol sequence suitable for frequency offset estimation, symbol-timing detection and channel estimation in the OQAM-MCT system. In this method, the pilot signal-sequence consists of a repeated series of the same data symbol. With this method, the pilot sequence approximately becomes equivalent to OFDM sequence and therefore existing pilot-assisted methods for OFDM are also applicable to OQAM-MCT system. Computer simulation results show that the OQAM-MCT system achieves both good transmission rate performance and low out-of-band radiation in PLC channels. It is also shown that the proposed pilot-sequence improves frequency offset estimation, symbol-timing detection and channel estimation performance as compared with the case of using pseudo-noise sequence.

  16. A comparative TCAD assessment of III-V channel materials for future high speed and low power logic applications

    Science.gov (United States)

    Gomes, U. P.; Takhar, K.; Ranjan, K.; Rathi, S.; Biswas, D.

    2015-02-01

    In this work, by means physics based drift-diffusion simulations, three different narrow band gap semiconductors; InAs, InSb and In0.53Ga0.47As, and their associated heterostructures have been studied for future high speed and low power logic applications. It is observed that In0.53Ga0.47As has higher immunity towards short channel effects with low DIBL and sub-threshold slope than InSb and InAs. Also it is observed that for the same device geometry InSb has the highest drive current and lower intrinsic delay but its ION/IOFF figure of merit is deteriorated due to excess leakage current.

  17. Cutting-in control of the variable speed constant frequency wind power generator based on internal model controller

    Energy Technology Data Exchange (ETDEWEB)

    Guo Jindong; Xu Honghua; Zhao Dongli [Inst. of Electrical Engineering, CAS, BJ (China)

    2008-07-01

    The no-impact-current cutting-in-network control is the key of variable speed constant frequency (VSCF) wind power control system. Based on the stator flux linkage oriented control theory of doubly fed induction generator (DFIG), the field-oriented vector control technique and the internal model controller (IMC) are transplanted into the voltage control of DFIG and a novel cutting-in control strategy is obtained. The strategy does not need the exact inductor generator model, and has perfect performance without overshoot. The structure of the controller is simple, and the only parameter to be adjusted is directly related to system performance, so the strategy is easy to realize. Finally the strategy is studied by simulation using Matlab, the results of the simulation show that the control strategy can effectively control the stator voltage. (orig.)

  18. Maximum Power Point Tracking in Variable Speed Wind Turbine Based on Permanent Magnet Synchronous Generator Using Maximum Torque Sliding Mode Control Strategy

    Institute of Scientific and Technical Information of China (English)

    Esmaeil Ghaderi; Hossein Tohidi; Behnam Khosrozadeh

    2017-01-01

    The present study was carried out in order to track the maximum power point in a variable speed turbine by minimizing electromechanical torque changes using a sliding mode control strategy.In this strategy,fhst,the rotor speed is set at an optimal point for different wind speeds.As a result of which,the tip speed ratio reaches an optimal point,mechanical power coefficient is maximized,and wind turbine produces its maximum power and mechanical torque.Then,the maximum mechanical torque is tracked using electromechanical torque.In this technique,tracking error integral of maximum mechanical torque,the error,and the derivative of error are used as state variables.During changes in wind speed,sliding mode control is designed to absorb the maximum energy from the wind and minimize the response time of maximum power point tracking (MPPT).In this method,the actual control input signal is formed from a second order integral operation of the original sliding mode control input signal.The result of the second order integral in this model includes control signal integrity,full chattering attenuation,and prevention from large fluctuations in the power generator output.The simulation results,calculated by using MATLAB/m-file software,have shown the effectiveness of the proposed control strategy for wind energy systems based on the permanent magnet synchronous generator (PMSG).

  19. A fully integral, differential, high-speed, low-power consumption CMOS recovery clock circuit

    Directory of Open Access Journals (Sweden)

    Daniel Pacheco Bautista

    2007-09-01

    Full Text Available The clock recovery circuit (CRC plays a fundamental role in electronic information recovery systems (hard disks, DVD and CD read/writeable units and baseband digital communication systems in recovering the clock signal contained in the received data. This signal is necessary for synchronising subsequent information processing. Nowadays, this task is difficult to achieve because of the data’s random nature and its high transfer rate. This paper presents the design of a high-performance integral CMOS technology clock recovery circuit (CRC wor-king at 1.2 Gbps and only consuming 17.4 mW using a 3.3V power supply. The circuit was fully differentially designed to obtain high performance. Circuit architecture was based on a conventional phase lock loop (PLL, current mode logic (MCML and a novel two stage ring-based voltage controlled oscillator (VCO. The design used 0.35 μm CMOS AMS process parameters. Hspice simulation results proved the circuit’s high performance, achieving tracking in less than 300 ns.

  20. The design and realization of general high-speed RAIN100B DAQ module based on powerPC MPC5200B processor

    International Nuclear Information System (INIS)

    Xue Tao; Gong Guanghua; Shao Beibei

    2010-01-01

    In order to deal with the DAQ function of nuclear electronics, department of engineering physics of Tsinghua University design and realize a general, high-speed RAIN100B DAQ module based on Freescale's PowerPC MPC5200B processor.And the RAIN100B was used on GEM detector DAQ, it can reach up to 90Mbps data speed. The result is also presented and discussed. (authors)

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

    International Nuclear Information System (INIS)

    Kim, Hye Ji; Yoon, Yong Tae

    2016-01-01

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

  2. Simulated front crawl swimming performance related to critical speed and critical power.

    Science.gov (United States)

    Toussaint, H M; Wakayoshi, K; Hollander, A P; Ogita, F

    1998-01-01

    Competitive pool swimming events range in distance from 50 to 1500 m. Given the difference in performance times (+/- 23-1000 s), the contribution of the aerobic and anaerobic energy systems changes considerably with race distance. In training practice the regression line between swimming distance and time (Distance = critical velocity x time + anaerobic swimming capacity) is used to determine the individual capacity of the aerobic and anaerobic metabolic pathways. Although there is confidence that critical velocity and anaerobic swimming capacity are fitness measures that separate aerobic and anaerobic components, a firm theoretical basis for the interpretation of these results does not exist. The purpose of this study was to evaluate the critical power concept and anaerobic swimming capacity as measures of the aerobic and anaerobic capacity using a modeling approach. A systems model was developed that relates the mechanics and energetics involved in front crawl swimming performance. From actual swimming flume measurements, the time dependent aerobic and anaerobic energy release was modeled. Data derived from the literature were used to relate the energy cost of front crawl swimming to swimming velocity. A balance should exist between the energy cost to swim a distance in a certain time and the concomitant aerobic and anaerobic energy release. The ensuing model was used to predict performance times over a range of distances (50-1500 m) and to calculate the regression line between swimming distance and time. Using a sensitivity analysis, it was demonstrated that the critical velocity is indicative for the capacity of the aerobic energy system. Estimates of the anaerobic swimming capacity, however, were influenced by variations in both anaerobic and aerobic energy release. Therefore, it was concluded that the anaerobic swimming capacity does not provide a reliable estimate of the anaerobic capacity.

  3. Possible standards for relieving the load of operational thermal power plants to the minimum of the power system's electric loads

    Energy Technology Data Exchange (ETDEWEB)

    Gitman, M.I.; Smirnov, I.A.

    1988-03-01

    Describes how operational measures involving feeding the steam extraction load into existing off-peak hot-water boilers produce a reduction in electric power at night and on public holidays by an average of 35% without the need for reconstruction, special equipment or changing the heat circuit. This method enables coal-fired central heating systems to be relieved by 20-30% and gaz-mazout systems (the majority) by 50-70%. To compensate for the loss of manoeuverability in central heating units on holidays in the colder period of the year, it may be necessary to stop supplementary power units (KEhS units) several times a year. 5 refs.

  4. Effect of 50 MeV Li3+ ion irradiation on electrical characteristics of high speed NPN power transistor

    International Nuclear Information System (INIS)

    Dinesh, C.M.; Ramani; Radhakrishna, M.C.; Dutt, R.N.; Khan, S.A.; Kanjilal, D.

    2008-01-01

    Silicon NPN overlay RF power high speed commercial bipolar junction transistors (BJTs) find applications in military, space and communication equipments. Here we report the effect of 50 MeV Li 3+ ion irradiation in the fluence range 1 x 10 11 -1.8 x 10 12 ions cm -2 on NPN power transistor. The range (R), electronic energy loss (S e ), nuclear energy loss (S n ), total ionizing dose (TID) and total displacement damage (D d ) in the silicon target are calculated from TRIM Monte Carlo Code. Output resistance is 3.568 x 10 4 Ω for unirradiated device and it increases to 6 x 10 7 Ω as the fluence is increased from 1 x 10 11 to 1.8 x 10 12 ions cm -2 . The capacitance of the emitter-base junction of the transistor decreases and dielectric loss of the emitter-base junction increases with increase in ion fluence. The built in voltage of the unirradiated sample is 0.5 V and it shifts to 0.4 V after irradiation at fluence of 1.8 x 10 12 ions cm -2 and the corresponding doping density reduced to 5.758 x 10 16 cm -3 . The charge carrier removal rate varies linearly with the increase in ion fluence

  5. Influence of the level of fit of a density probability function to wind-speed data on the WECS mean power output estimation

    International Nuclear Information System (INIS)

    Carta, Jose A.; Ramirez, Penelope; Velazquez, Sergio

    2008-01-01

    Static methods which are based on statistical techniques to estimate the mean power output of a WECS (wind energy conversion system) have been widely employed in the scientific literature related to wind energy. In the static method which we use in this paper, for a given wind regime probability distribution function and a known WECS power curve, the mean power output of a WECS is obtained by resolving the integral, usually using numerical evaluation techniques, of the product of these two functions. In this paper an analysis is made of the influence of the level of fit between an empirical probability density function of a sample of wind speeds and the probability density function of the adjusted theoretical model on the relative error ε made in the estimation of the mean annual power output of a WECS. The mean power output calculated through the use of a quasi-dynamic or chronological method, that is to say using time-series of wind speed data and the power versus wind speed characteristic of the wind turbine, serves as the reference. The suitability of the distributions is judged from the adjusted R 2 statistic (R a 2 ). Hourly mean wind speeds recorded at 16 weather stations located in the Canarian Archipelago, an extensive catalogue of wind-speed probability models and two wind turbines of 330 and 800 kW rated power are used in this paper. Among the general conclusions obtained, the following can be pointed out: (a) that the R a 2 statistic might be useful as an initial gross indicator of the relative error made in the mean annual power output estimation of a WECS when a probabilistic method is employed; (b) the relative errors tend to decrease, in accordance with a trend line defined by a second-order polynomial, as R a 2 increases

  6. Influence of the level of fit of a density probability function to wind-speed data on the WECS mean power output estimation

    Energy Technology Data Exchange (ETDEWEB)

    Carta, Jose A. [Department of Mechanical Engineering, University of Las Palmas de Gran Canaria, Campus de Tafira s/n, 35017 Las Palmas de Gran Canaria, Canary Islands (Spain); Ramirez, Penelope; Velazquez, Sergio [Department of Renewable Energies, Technological Institute of the Canary Islands, Pozo Izquierdo Beach s/n, 35119 Santa Lucia, Gran Canaria, Canary Islands (Spain)

    2008-10-15

    Static methods which are based on statistical techniques to estimate the mean power output of a WECS (wind energy conversion system) have been widely employed in the scientific literature related to wind energy. In the static method which we use in this paper, for a given wind regime probability distribution function and a known WECS power curve, the mean power output of a WECS is obtained by resolving the integral, usually using numerical evaluation techniques, of the product of these two functions. In this paper an analysis is made of the influence of the level of fit between an empirical probability density function of a sample of wind speeds and the probability density function of the adjusted theoretical model on the relative error {epsilon} made in the estimation of the mean annual power output of a WECS. The mean power output calculated through the use of a quasi-dynamic or chronological method, that is to say using time-series of wind speed data and the power versus wind speed characteristic of the wind turbine, serves as the reference. The suitability of the distributions is judged from the adjusted R{sup 2} statistic (R{sub a}{sup 2}). Hourly mean wind speeds recorded at 16 weather stations located in the Canarian Archipelago, an extensive catalogue of wind-speed probability models and two wind turbines of 330 and 800 kW rated power are used in this paper. Among the general conclusions obtained, the following can be pointed out: (a) that the R{sub a}{sup 2} statistic might be useful as an initial gross indicator of the relative error made in the mean annual power output estimation of a WECS when a probabilistic method is employed; (b) the relative errors tend to decrease, in accordance with a trend line defined by a second-order polynomial, as R{sub a}{sup 2} increases. (author)

  7. The Effects of Frontal- and Sagittal-Plane Plyometrics on Change-of-Direction Speed and Power in Adolescent Female Basketball Players.

    Science.gov (United States)

    McCormick, Brian T; Hannon, James C; Newton, Maria; Shultz, Barry; Detling, Nicole; Young, Warren B

    2016-01-01

    Plyometrics is a popular training modality for basketball players to improve power and change-of-direction speed. Most plyometric training has used sagittal-plane exercises, but improvements in change-of-direction speed have been greater in multi-direction programs. To determine the benefits of a 6-wk frontal-plane plyometric (FPP) training program compared with a 6-wk sagittal-plane plyometric (SPP) training program with regard to power and change-of-direction speed. Fourteen female varsity high school basketball players participated in the study. Multiple 2 × 2 repeated-measures ANOVAs were used to determine differences for the FPP and SPP groups from preintervention to postintervention on 4 tests of power and 2 tests of change-of-direction speed. There was a group main effect for time in all 6 tests. There was a significant group × time interaction effect in 3 of the 6 tests. The SPP improved performance of the countermovement vertical jump more than the FPP, whereas the FPP improved performance of the lateral hop (left) and lateral-shuffle test (left) more than the SPP. The standing long jump, lateral hop (right), and lateral-shuffle test (right) did not show a significant interaction effect. These results suggest that basketball players should incorporate plyometric training in all planes to improve power and change-of-direction speed.

  8. Minimum short-circuit ratios for grid interconnection of wind farms with induction generators

    Energy Technology Data Exchange (ETDEWEB)

    Reginatto, Romeu; Rocha, Carlos [Western Parana State University (UNIOESTE), Foz do Iguacu, PR (Brazil). Center for Engineering and Exact Sciences], Emails: romeu@unioeste.br, croberto@unioeste.br

    2009-07-01

    This paper concerns the problem of determining the minimum value for the short-circuit ratio which is adequate for the interconnection of a given wind farms to a given grid point. First, a set of 3 criteria is defined in order to characterize the quality/safety of the interconnection: acceptable terminal voltage variations, a minimum active power margin, and an acceptable range for the internal voltage angle. Then, the minimum short circuit ratio requirement is determined for 6 different induction generator based wind turbines, both fixed-speed (with and without reactive power compensation) and variable-speed (with the following control policies: reactive power, power factor, and terminal voltage regulation). The minimum short-circuit ratio is determined and shown in graphical results for the 6 wind turbines considered, for X/R in the range 0-15, also analyzing the effect of more/less stringent tolerances for the interconnection criteria. It is observed that the tighter the tolerances the larger the minimum short-circuit ratio required. For the same tolerances in the interconnection criteria, a comparison of the minimum short circuit ratio required for the interconnection of both squirrel-cage and doubly-fed induction generators is presented, showing that the last requires much smaller values for the short-circuit ratio. (author)

  9. 风力发电系统中的风速测量技术%Wind Speed Measurement Technology in Wind Power Generation System

    Institute of Scientific and Technical Information of China (English)

    雷鹏; 刘文红; 张帅; 邱天爽

    2015-01-01

    风速测量在风力发电系统中影响着风力机组的转速和功率的控制,风速值的准确性将影响整个风机的效率.首先介绍了几种在风力发电系统中常用的风速测量仪,简述了其原理、结构特点,然后分析了各种风速测量方法的优缺点及适用范围,最后展望了软测量技术在风力发电系统风速测量中的应用前景.%The wind speed measurement in wind power system, the influence of the wind turbine speed and power control, the accuracy of the wind speed value will affect the efficiency of the whole wind turbine. In this paper, the wind speed measuring instrument for wind power generation system is introduced, and its principle and structure characteristics are described. Then the advantages and disadvantages of various wind speed measurement methods are analyzed.

  10. Voluntary muscle activation improves with power training and is associated with changes in gait speed in mobility-limited older adults

    DEFF Research Database (Denmark)

    Hvid, Lars G; Strotmeyer, Elsa S; Skjødt, Mathias

    2016-01-01

    Incomplete voluntary muscle activation may contribute to impaired muscle mechanical function and physical function in older adults. Exercise interventions have been shown to increase voluntary muscle activation, although the evidence is sparse for mobility-limited older adults, particularly...... in association with physical function. This study examined the effects of 12weeks of power training on outcomes of voluntary muscle activation and gait speed in mobility-limited older adults from the Healthy Ageing Network of Competence (HANC) study. We included 37 older men and women with a usual gait speed...... in TG (r=0.67, pactivation is improved in mobility-limited older adults following 12-weeks of progressive power training, and is associated with improved maximal gait speed. Incomplete voluntary muscle activation should be considered one of the key mechanisms...

  11. Analog circuits using FinFETs: benefits in speed-accuracy-power trade-off and simulation of parasitic effects

    Directory of Open Access Journals (Sweden)

    M. Fulde

    2007-06-01

    Full Text Available Multi-gate FET, e.g. FinFET devices are the most promising contenders to replace bulk FETs in sub-45 nm CMOS technologies due to their improved sub threshold and short channel behavior, associated with low leakage currents. The introduction of novel gate stack materials (e.g. metal gate, high-k dielectric and modified device architectures (e.g. fully depleted, undoped fins affect the analog device properties significantly. First measurements indicate enhanced intrinsic gain (gm/gDS and promising matching behavior of FinFETs. The resulting benefits regarding the speed-accuracy-power trade-off in analog circuit design will be shown in this work. Additionally novel device specific effects will be discussed. The hysteresis effect caused by charge trapping in high-k dielectrics or self-heating due to the high thermal resistor of the BOX isolation are possible challenges for analog design in these emerging technologies. To gain an early assessment of the impact of such parasitic effects SPICE based models are derived and applied in analog building blocks.

  12. Effect of laser power and scanning speed on laser deposited Ti6Al4V/TiB2 matrix composites

    CSIR Research Space (South Africa)

    Mokgalaka, MN

    2012-10-01

    Full Text Available Additive Manufacturing in Industry Conference, Kwa Maritane, Pilanesberg National Park, 31 October-2 November 2012 EFFECT OF LASER POWER AND SCANNING SPEED ON LASER DEPOSITED Ti6Al4V/TiB2 MATRIX COMPOSITES M.N. Mokgalaka2,1, S.L. Pityana1,2, A.P.I...

  13. Extending the Constant Power Speed Range of the Brushless DC Motor through Dual Mode Inverter Control - Part II: Laboratory Proof-of-Principle

    International Nuclear Information System (INIS)

    Lawler, J.S.

    2001-01-01

    Previous theoretical work has shown that when all loss mechanisms are neglected the constant power speed range (CPSR) of a brushless dc motor (BDCM) is infinite when the motor is driven by the dual-mode inverter control (DMIC)[1,2]. In a physical drive, losses, particularly speed-sensitive losses, will limit the CPSR to a finite value. In this paper we report the results of laboratory testing of a low-inductance, 7.5-hp BDCM driven by the DMIC. The speed rating of the test motor rotor limited the upper speed of the testing, and the results show that the CPSR of the test machine is greater than 6:1 when driven by the DMIC. Current wave shape, peak, and rms values remained controlled and within rating over the entire speed range. The laboratory measurements allowed the speed-sensitive losses to be quantified and incorporated into computer simulation models, which then accurately reproduce the results of lab testing. The simulator shows that the limiting CPSR of the test motor is 8:1. These results confirm that the DMIC is capable of driving low-inductance BDCMs over the wide CPSR that would be required in electric vehicle applications

  14. A reduced switch count UPF power conditioner for grid connected variable speed wind energy conversion system employing PM generators: a simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Raju, A.B.; Fernandes, B.G.; Chatterjee, K. [Indian Institute of Technology, Mumbai (India). Dept. of Electrical Engineering

    2004-07-01

    In this paper, modelling and simulation of a grid connected variable speed wind energy conversion system (VSWECS) with reduced switch count power converter is presented. The system consists of a permanent magnet synchronous generator (PMSG), two-pulse width modulated B-4 power converters and a maximum power point tracker (MPPT). Mathematical models of each element of the system are developed separately and are then integrated to simulate the whole system for various wind velocities. The complete system is simulated using MATLAB/SIMULINK and simulation results are presented. (author)

  15. Development of sensor-less control strategies for grid connected PMSG based variable speed wind energy conversion system with improved power quality features

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, A. [Quebec Univ., Montreal, PQ (Canada). Dept. of Electrical Engineering

    2010-07-01

    Interest in renewable energy sources has grown in recent years in response to concerns of increasing pollution levels and depleting fossil fuels. Among renewable energy sources, wind energy generation is the fastest growing technology and one of the most cost-effective and environmental friendly means to generate electricity from renewable sources. Modern wind turbines are ready to be deployed in large scale as a result of recent developments in wind power technology. Variable speed permanent magnet synchronous generators (PMSG) based wind energy conversion systems (WECS) are becoming more popular. The use of a permanent magnet reduces size, cost and weight of overall WECS. In addition, the absence of field winding and its excitation system avoids heat dissipation in the rotor winding, thereby improving overall efficiency of the WECS. This type of configuration is more appropriate for remote locations, particularly for off-shore wind application, where the geared doubly fed induction generator usually requires regular maintenance due to tearing-wearing in brushes, windings and gear box. This presentation discussed the development of sensor-less control strategies for grid connected PMSG based variable speed wind energy conversion system with improved power quality features. A novel adaptive network-based fuzzy inference system was used to estimate the speed and position of variable speed PMSG under fluctuating wind conditions. A novel control strategy was developed for the grid interfacing inverter incorporating power quality improvement features at point of common coupling.

  16. Utility-scale variable-speed wind turbines using a doubly-fed generator with a soft-switching power converter

    Energy Technology Data Exchange (ETDEWEB)

    Weigand, C.H.; Lauw, H.K.; Marckx, D.A. [Electronic Power Conditioning, Inc., Corvallis, OR (United States)

    1996-12-31

    Utility-scale wind turbines operating at variable RPM have been studied for a considerable period of time. Whereas the increase in energy output originally has been considered the principal benefit of variable-speed operation, the ability to tightly control the drive-train torque by electronic means is becoming another very important cost factor, especially for turbine ratings above 500 kilowatts. This cost benefit becomes even more significant as optimum turbine ratings today are approaching (and surpassing) 1 Megawatt. Having identified the benefits for the turbine, the designer is confronted with the task of finding the most cost-effective variable-speed generation system which allows him to make use of the benefits, yet does not introduce well-known electrical problems associated with state-of-the-art variable-speed generator controls, such as drastically reduced generator winding life, excessive harmonics on the utility, and poor utility power factor. This paper will indicate that for high-power (> 500 kW), utility-scale wind turbines a doubly-fed generator system in connection with a soft-switching resonant power converter is the least-cost variable-speed generation system offering all of the desired benefits, yet avoids the introduction of the potential electrical problems stated above. 3 refs., 3 figs., 1 tab.

  17. Training-induced annual changes in red blood cell profile in highly-trained endurance and speed-power athletes.

    Science.gov (United States)

    Ciekot-Sołtysiak, Monika; Kusy, Krzysztof; Podgórski, Tomasz; Zieliński, Jacek

    2017-10-24

    An extensive body of literature exists on the effects of training on haematological parameters, but the previous studies have not reported how hematological parameters respond to changes in training loads within consecutive phases of the training cycle in highly-trained athletes in extremely different sport disciplines. The aim of this study was to identify changes in red blood cell (RBC) profile in response to training loads in consecutive phases of the annual training cycle in highly-trained sprinters (8 men, aged 24 ± 3 years) and triathletes (6 men, aged 24 ± 4 years) who competed at the national and international level. Maximal oxygen uptake (VO2max), RBC, haemoglobin (Hb), haematocrit (Ht), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC) and RBC distribution width (RDW) were determined in four characteristic training phases (transition, general subphase of the preparation phase, specific subphase of the preparation phase and competition phase). Our main findings are that (1) Hb, MCH and MCHC in triathletes and MCV in both triathletes and sprinters changed significantly over the annual training cycle, (2) triathletes had significantly higher values than sprinters only in case of MCH and MCHC after the transition and general preparation phases but not after the competition phase when MCH and MCHC were higher in sprinters and (3) in triathletes, Hb, MCH and MCHC substantially decreased after the competition phase, which was not observed in sprinters. The athletes maintained normal ranges of all haematological parameters in four characteristic training phases. Although highly-trained sprinters and triathletes do not significantly differ in their levels of most haematological parameters, these groups are characterized by different patterns of changes during the annual training cycle. Our results suggest that when interpreting the values of haematological parameters in speed-power and endurance

  18. Control and Health Monitoring of Variable Speed Wind Power Generation Systems; Period of Performance: 10 July 1997 - 10 July 2000

    Energy Technology Data Exchange (ETDEWEB)

    Song, Y. D.; Bikdash, M.; Schulz, M. J.

    2001-09-01

    This document reports accomplishments on variable speed control, furling analysis, and health monitoring of wind turbines. There are three parts, prepared by Song, Bikdash, and Schulz, respectively. The first part discusses variable-speed control of wind turbines, exploring a memory-based method for wind speed prediction and wind turbine control. The second part addresses the yaw dynamics of wind turbines, including modeling, analysis, and control. The third part of the report discusses new analytical techniques that were developed and tested to detect initial damage to prevent failures of wind turbine rotor blades.

  19. A Systematic Review of the Association Between Physical Fitness and Musculoskeletal Injury Risk: Part 3 - Flexibility, Power, Speed, Balance, and Agility.

    Science.gov (United States)

    de la Motte, Sarah J; Lisman, Peter; Gribbin, Timothy C; Murphy, Kaitlin; Deuster, Patricia A

    2017-12-11

    We performed a systematic review and evaluation of the existing scientific literature on the association between flexibility, power, speed, balance, and agility, and musculoskeletal injury (MSK-I) risk in military and civilian populations. MEDLINE, EBSCO, EMBASE, and the Defense Technical Information Center were searched for original studies published from 1970 through 2015 that examined associations between these physical fitness measures (flexibility, power, speed, balance, and agility) and MSK-I. Methodological quality and strength of the evidence were determined following criteria adapted from previously published systematic reviews. Twenty-seven of 4,229 citations met our inclusion criteria. Primary findings indicate there is (a) moderate evidence that hamstring flexibility, as measured by performance on a sit-and-reach test or active straight-leg raise test assessed with goniometry, and ankle flexibility, assessed with goniometry, are associated with MSK-I risk; (b) moderate evidence that lower body power, as measured by performance on a standing broad jump or vertical jump with no countermovement, is associated with MSK-I risk; (c) moderate evidence that slow sprint speed is associated with MSK-I risk; (d) moderate evidence that poor performance on a single-leg balance test is associated with increased risk for ankle sprain; and (e) insufficient evidence that agility is associated with MSK-I risk. Several measures of flexibility, power, speed, and balance are risk factors for training-related MSK-I in military and civilian athletic populations. Importantly, these findings can be useful for military, first responder, and athletic communities who are seeking evidence-based metrics for assessing or stratifying populations for risk of MSK-I.

  20. THE EFFECTS OF SINGLE LEG HOP PROGRESSION AND DOUBLE LEGS HOP PROGRESSION EXERCISE TO INCREASE SPEED AND EXPLOSIVE POWER OF LEG MUSCLE

    Directory of Open Access Journals (Sweden)

    Nining W. Kusnanik

    2015-05-01

    Full Text Available The main purpose of this study was to determine the effect of single leg hop progression and double legs hop progression exercise to increase speed and explosive power of leg muscles. Plyometric is one of the training methods that can increase explosive power. There are many models of plyometric training including single leg hop progression and double leg hop progression. This research was experimental using match subject design techniques. The subjects of this study were 39 students who joined basketball school club. There were 3 groups in this study: Group 1 were 13 students who given sin¬gle leg hop progression exercise, Group 2 were 13 students who given double legs hop progression exercise, Group 3 were 13 students who given conventional exercise. The data was collected during pre test and post test by testing 30m speed running and vertical jump. The data was analyzed using Analysis of Varians (Anova. It was found that there were significantly increased on speed and explosive power of leg muscles of Group 1 and Group 2. It can be stated that single leg hop progression exercise was more effective than double leg hop progression exercise. The recent findings supported the hypothesis that single leg hop progression and double legs hop progression exercise can increase speed and explosive power of leg muscles. These finding were supported by some previous studies (Singh, et al, 2011; Shallaby, H.K., 2010. The single leg hop progression is more effective than double legs hop progression. This finding was consistent with some previous evidences (McCurdy, et al, 2005; Makaruk et al, 2011.

  1. Influence of the Overlapping Factor and Welding Speed on T-Joint Welding of Ti6Al4V and Inconel 600 Using Low-Power Fiber Laser

    Directory of Open Access Journals (Sweden)

    Shamini Janasekaran

    2016-06-01

    Full Text Available Double-sided laser beam welding of skin-stringer joints is an established method for many applications. However, in certain cases with limited accessibility, single-sided laser beam joining is considered. In the present study, single-sided welding of titanium alloy Ti6Al4V and nickel-based alloy Inconel 600 in a T-joint configuration was carried out using continuous-wave (CW, low-power Ytterbium (Yb-fiber laser. The influence of the overlapping factor and welding speed of the laser beam on weld morphology and properties was investigated using scanning electron microscopy (SEM and X-ray diffraction (XRD, respectively. XRD analysis revealed the presence of intermetallic layers containing NiTi and NiTi2 at the skin-stringer joint. The strength of the joints was evaluated using pull testing, while the hardness of the joints was analyzed using Vickers hardness measurement at the base metal (BM, fusion zone (FZ and heat-affected zone (HAZ. The results showed that the highest force needed to break the samples apart was approximately 150 N at a laser welding power of 250 W, welding speed of 40 mm/s and overlapping factor of 50%. During low-power single-sided laser welding, the properties of the T-joints were affected by the overlapping factor and laser welding speed.

  2. Evaluation of single tracks of 17-4PH steel manufactured at different power densities and scanning speeds by selective laser melting

    Directory of Open Access Journals (Sweden)

    Makoana, N. W.

    2016-11-01

    Full Text Available In Selective Laser Melting, the initial units produced are single tracks that overlap to create a single layer; from the sequence of layers, a 3D object is manufactured. The properties of the parts produced by SLM depend heavily on the properties of each single track and each layer formed by these tracks. This study evaluates the effect of processing parameters on the geometrical characteristics of single tracks manufactured from 17-4PH stainless steel powder. A single-mode continuous-wave ytterbium fibre laser was used to manufacture single tracks at laser powers in the range of 100-300 W with a constant spot size of ∼80μm. The single tracks produced were subjected to standard metallographic preparation techniques for further analysis with an optical microscope. Deep molten pool shapes were observed at low scan speeds, while shallow molten pool shapes were observed at high scan speeds. At higher laser power densities, under-cutting and humping effects were also observed. The dimensions of single tracks processed without powder generally decrease with increasing scan speed at constant laser power. However, the geometrical features of the single tracks processed with powder revealed pronounced irregularities believed to be caused by non-homogeneity in the deposited powder layer.

  3. Variability Extraction and Synthesis via Multi-Resolution Analysis using Distribution Transformer High-Speed Power Data

    Energy Technology Data Exchange (ETDEWEB)

    Chamana, Manohar [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Mather, Barry A [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-10-19

    A library of load variability classes is created to produce scalable synthetic data sets using historical high-speed raw data. These data are collected from distribution monitoring units connected at the secondary side of a distribution transformer. Because of the irregular patterns and large volume of historical high-speed data sets, the utilization of current load characterization and modeling techniques are challenging. Multi-resolution analysis techniques are applied to extract the necessary components and eliminate the unnecessary components from the historical high-speed raw data to create the library of classes, which are then utilized to create new synthetic load data sets. A validation is performed to ensure that the synthesized data sets contain the same variability characteristics as the training data sets. The synthesized data sets are intended to be utilized in quasi-static time-series studies for distribution system planning studies on a granular scale, such as detailed PV interconnection studies.

  4. A Comprehensive Review of Low-Voltage-Ride-Through Methods for Fixed-Speed Wind Power Generators

    DEFF Research Database (Denmark)

    Moghadasi, Amirhasan; Sarwat, Arif; Guerrero, Josep M.

    2016-01-01

    This paper presents a comprehensive review of various techniques employed to enhance the low voltage ride through (LVRT) capability of the fixed-speed induction generators (FSIGs)-based wind turbines (WTs), which has a non-negligible 20% contribution of the existing wind energy in the world...

  5. A Multi-Point Method Considering the Maximum Power Point Tracking Dynamic Process for Aerodynamic Optimization of Variable-Speed Wind Turbine Blades

    Directory of Open Access Journals (Sweden)

    Zhiqiang Yang

    2016-05-01

    Full Text Available Due to the dynamic process of maximum power point tracking (MPPT caused by turbulence and large rotor inertia, variable-speed wind turbines (VSWTs cannot maintain the optimal tip speed ratio (TSR from cut-in wind speed up to the rated speed. Therefore, in order to increase the total captured wind energy, the existing aerodynamic design for VSWT blades, which only focuses on performance improvement at a single TSR, needs to be improved to a multi-point design. In this paper, based on a closed-loop system of VSWTs, including turbulent wind, rotor, drive train and MPPT controller, the distribution of operational TSR and its description based on inflow wind energy are investigated. Moreover, a multi-point method considering the MPPT dynamic process for the aerodynamic optimization of VSWT blades is proposed. In the proposed method, the distribution of operational TSR is obtained through a dynamic simulation of the closed-loop system under a specific turbulent wind, and accordingly the multiple design TSRs and the corresponding weighting coefficients in the objective function are determined. Finally, using the blade of a National Renewable Energy Laboratory (NREL 1.5 MW wind turbine as the baseline, the proposed method is compared with the conventional single-point optimization method using the commercial software Bladed. Simulation results verify the effectiveness of the proposed method.

  6. Quadriceps strength, quadriceps power, and gait speed in older U.S. adults with diabetes mellitus: results from the National Health and Nutrition Examination Survey, 1999-2002.

    Science.gov (United States)

    Kalyani, Rita Rastogi; Tra, Yolande; Yeh, Hsin-Chieh; Egan, Josephine M; Ferrucci, Luigi; Brancati, Frederick L

    2013-05-01

    To examine the independent association between diabetes mellitus (and its duration and severity) and quadriceps strength, quadriceps power, and gait speed in a national population of older adults. Cross-sectional nationally representative survey. United States. Two thousand five hundred seventy-three adults aged 50 and older in the National Health and Nutrition Examination Survey 1999-2002 who had assessment of quadriceps strength. Diabetes mellitus was ascertained according to questionnaire. Measurement of isokinetic knee extensor (quadriceps) strength was performed at 60º/s. Gait speed was assessed using a 20-foot walk test. Multiple linear regression analyses were used to assess the association between diabetes mellitus status and outcomes, adjusting for potential confounders or mediators. Older U.S. adults with diabetes mellitus had significantly slower gait speed (0.96 ± 0.02 m/s) than those without (1.08 ± 0.01 m/s; P diabetes mellitus was also associated with significantly lower quadriceps strength (-4.6 ± 1.9 Nm; P = .02) and power (-4.9 ± 2.0 W; P = .02) and slower gait speed (-0.05 ± 0.02 m/s; P = .002). Associations remained significant after adjusting for physical activity and C-reactive protein. After accounting for comorbidities (cardiovascular disease, peripheral neuropathy, amputation, cancer, arthritis, fracture, chronic obstructive pulmonary disease), diabetes mellitus was independently associated only with gait speed (-0.04 ± 0.02 m/s; P = .02). Diabetes mellitus duration in men and women was negatively associated with age-adjusted quadriceps strength (-5.7 and -3.5 Nm/decade of diabetes mellitus, respectively) and power (-6.1 and -3.8 W/decade of diabetes mellitus, respectively) (all P ≤ .001, no significant interactions according to sex). Glycosylated hemoglobin was not associated with outcomes after accounting for body weight. Older U.S. adults with diabetes mellitus have lower quadriceps strength and quadriceps power that is related

  7. Coupling between minimum scattering antennas

    DEFF Research Database (Denmark)

    Andersen, J.; Lessow, H; Schjær-Jacobsen, Hans

    1974-01-01

    Coupling between minimum scattering antennas (MSA's) is investigated by the coupling theory developed by Wasylkiwskyj and Kahn. Only rotationally symmetric power patterns are considered, and graphs of relative mutual impedance are presented as a function of distance and pattern parameters. Crossed...

  8. Integrated Power and Attitude Control Design of Satellites Based on a Fuzzy Adaptive Disturbance Observer Using Variable-Speed Control Moment Gyros

    Directory of Open Access Journals (Sweden)

    Zhongyi Chu

    2016-01-01

    Full Text Available To satisfy the requirements for small satellites that seek agile slewing with peak power, this paper investigates integrated power and attitude control using variable-speed control moment gyros (VSCMGs that consider the mass and inertia of gimbals and wheels. The paper also details the process for developing the controller by considering various environments in which the controller may be implemented. A fuzzy adaptive disturbance observer (FADO is proposed to estimate and compensate for the effects of equivalent disturbances. The algorithms can simultaneously track attitude and power. The simulation results illustrate the effectiveness of the control approach, which exhibits an improvement of 80 percent compared with alternate approaches that do not employ a FADO.

  9. A data mining approach: Analyzing wind speed and insolation period data in Turkey for installations of wind and solar power plants

    International Nuclear Information System (INIS)

    Colak, Ilhami; Sagiroglu, Seref; Demirtas, Mehmet; Yesilbudak, Mehmet

    2013-01-01

    Highlights: ► Wind speed and insolation period data were analyzed using a data mining approach. ► Most of the studies in the literature were based on Weibull and Rayleigh models. ► Nearest and farest neighbor algorithms were used with different distance metrics. ► Many inferences were achieved in efficient limits for wind and solar farm analyses. - Abstract: Wind and solar power plant installations have been recently increased rapidly with respect to the depletion of fossil-based fuels all over the world. Due to stochastic nature of meteorological conditions, wind and solar energies have a non-schedulable nature and they require several installation analyses to determine the location and the capacities of wind and solar power to be produced. This paper focuses on the similarity, feasibility and numerical analyses of 75 cities in Turkey based on the monthly average wind speed and insolation period data. The nearest and the farest neighbor algorithms are used as agglomerative hierarchical clustering methods with Euclidean, Manhattan and Minkowski distance metrics in the stage of making the similarity and feasibility analyses. The maximum cophenetic correlation coefficient is achieved by the nearest neighbor algorithm with the Minkowski distance metric in the similarity and feasibility analyses. On the other hand, graphical representations of the monthly average wind speed and insolation period data are utilized for making the numerical analysis. The highest annual average wind speed and insolation period are obtained as 3.88 m/s and 8.45 h/day, respectively. Overall, many inferences were achieved in acceptable and efficient limits for wind and solar energy.

  10. Intercommunications of indexes of speed and power qualities of sportsmen single combat on the stage of the specialized base preparation

    Directory of Open Access Journals (Sweden)

    A.O. Nykytenko

    2013-01-01

    Full Text Available The purpose of work is a study of interdependence between indexes specially-preparatory and general preparatory exercises of sportsmen (boxing, sporting hand-to-hand fight hopak, fencing. 42 sportsmen took part in researches. Statistical reliable intercommunications are set: a indexes of force of shots by hands with the indexes of rate of single movement; b indexes of force of shots by feet with indexes from maximal force of muscles (tractive forces; c indexes of speed of shots by hands (pricking with the indexes of distance of shove of balls by mass 300 gramme; d indexes of speed of movement a step in a battle bar with indexes: speeds of shots by hands (pricking; e indexes of frequency of shots of boxers and sportsmen hand-to-hand fight hopak with the indexes of frequency of movement (manoeuvring on feet. Facilities which it is expedient to apply in the training process of single combats on this stage of long-term preparation are certain.

  11. Correlation between cortical beta power and gait speed is suppressed in a parkinsonian model, but restored by therapeutic deep brain stimulation.

    Science.gov (United States)

    Polar, Christian A; Gupta, Rahul; Lehmkuhle, Mark J; Dorval, Alan D

    2018-05-30

    The motor cortex and subthalamic nucleus (STN) of patients with Parkinson's disease (PD) exhibit abnormally high levels of electrophysiological oscillations in the ~12-35 Hz beta-frequency range. Recent studies have shown that beta is partly carried forward to regulate future motor states in the healthy condition, suggesting that steady state beta power is lower when a sequence of movements occurs in a short period of time, such as during fast gait. However, whether this relationship between beta power and motor states persists upon parkinsonian onset or in response to effective therapy is unclear. Using a 6-hydroxy dopamine (6-OHDA) rat model of PD and a custom-built behavioral and neurophysiological recording system, we aimed to elucidate a better understanding of the mechanisms underlying cortical beta power and PD symptoms. In addition to elevated levels of beta oscillations, we show that parkinsonian onset was accompanied by a decoupling of movement intensity - quantified as gait speed - from cortical beta power. Although subthalamic deep brain stimulation (DBS) reduced general levels of beta oscillations in the cortex of all PD animals, the brain's capacity to regulate steady state levels of beta power as a function of movement intensity was only restored in animals with therapeutic DBS. We propose that, in addition to lowering general levels of cortical beta power, restoring the brain's ability to maintain this inverse relationship is critical for effective symptom suppression. Copyright © 2017. Published by Elsevier Inc.

  12. Maximum Power Point Tracking Control of Hydrokinetic Turbine and Low-speed High-Thrust Permanent Magnet Generator Design

    Science.gov (United States)

    2012-01-01

    MPPT control method is similar to hill-climbing used as MPPT control in photovoltaic ...climbing method used as MPPT control in photovoltaic systems. In addition, the proposed MPPT control strategy is generic to all the hydrokinetic...convert AC power from the generator into DC power and a boost converter is used to implement energy flow control . On the load side, an electronic

  13. Rotor Speed Control of a Direct-Driven Permanent Magnet Synchronous Generator-Based Wind Turbine Using Phase-Lag Compensators to Optimize Wind Power Extraction

    Directory of Open Access Journals (Sweden)

    Ester Hamatwi

    2017-01-01

    Full Text Available Due to the intermittent nature of wind, the wind power output tends to be inconsistent, and hence maximum power point tracking (MPPT is usually employed to optimize the power extracted from the wind resource at a wide range of wind speeds. This paper deals with the rotor speed control of a 2 MW direct-driven permanent magnet synchronous generator (PMSG to achieve MPPT. The proportional-integral (PI, proportional-derivative (PD, and proportional-integral-derivative (PID controllers have widely been employed in MPPT studies owing to their simple structure and simple design procedure. However, there are a number of shortcomings associated with these controllers; the trial-and-error design procedure used to determine the P, I, and D gains presents a possibility for poorly tuned controller gains, which reduces the accuracy and the dynamic performance of the entire control system. Moreover, these controllers’ linear nature, constricted operating range, and their sensitivity to changes in machine parameters make them ineffective when applied to nonlinear and uncertain systems. On the other hand, phase-lag compensators are associated with a design procedure that is well defined from fundamental principles as opposed to the aforementioned trial-and-error design procedure. This makes the latter controller type more accurate, although it is not well developed yet, and hence it is the focus of this paper. The simulation results demonstrated the effectiveness of the proposed MPPT controller.

  14. Variable Speed Rotor System, Phase I

    Data.gov (United States)

    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...

  15. Minimum throttling feedwater control in VVER-1000 and PWR NPPs

    International Nuclear Information System (INIS)

    Symkin, B.E.; Thaulez, F.

    2004-01-01

    This paper presents an approach for the design and implementation of advanced digital control systems that use a minimum-throttling algorithm for the feedwater control. The minimum-throttling algorithm for the feedwater control, i.e. for the control of steam generators level and of the feedwater pumps speed, is applicable for NPPs with variable speed feedwater pumps. It operates in such a way that the feedwater control valve in the most loaded loop is wide open, steam generator level in this loop being controlled by the feedwater pumps speed, while the feedwater control valves in the other loops are slightly throttling under the action of their control system, to accommodate the slight loop imbalances. This has the advantage of minimizing the valve pressure losses hence minimizing the feedwater pumps power consumption and increasing the net MWe. The benefit has been evaluated for specific plants as being roughly 0.7 and 2.4 MW. The minimum throttling mode has the further advantages of lowering the actuator efforts with potential positive impact in actuator life and of minimizing the feedwater pipelines vibrations. The minimum throttling mode of operation has been developed by the Ukrainian company LvivORGRES. It has been applied with great deal of success on several VVER-1000 NPPs, six units of Zaporizhzha in Ukraine plus, with participation of Westinghouse, Kozloduy 5 and 6 in Bulgaria and South Ukraine 1 to 3 in Ukraine. The concept operates with both ON-OFF valves and true control valves. A study, jointly conducted by Westinghouse and LvivORGRES, is ongoing to demonstrate the applicability of the concept to PWRs having variable speed feedwater pumps and having, or installing, digital feedwater control, standalone or as part of a global digital control system. The implementation of the algorithm at VVER-1000 plants provided both safety improvement and direct commercial benefits. The minimum-throttling algorithm will similarly increase the performance of PWRs. The

  16. Validation of temporal and spatial consistency of facility- and speed-specific vehicle-specific power distributions for emission estimation: A case study in Beijing, China.

    Science.gov (United States)

    Zhai, Zhiqiang; Song, Guohua; Lu, Hongyu; He, Weinan; Yu, Lei

    2017-09-01

    Vehicle-specific power (VSP) has been found to be highly correlated with vehicle emissions. It is used in many studies on emission modeling such as the MOVES (Motor Vehicle Emissions Simulator) model. The existing studies develop specific VSP distributions (or OpMode distribution in MOVES) for different road types and various average speeds to represent the vehicle operating modes on road. However, it is still not clear if the facility- and speed-specific VSP distributions are consistent temporally and spatially. For instance, is it necessary to update periodically the database of the VSP distributions in the emission model? Are the VSP distributions developed in the city central business district (CBD) area applicable to its suburb area? In this context, this study examined the temporal and spatial consistency of the facility- and speed-specific VSP distributions in Beijing. The VSP distributions in different years and in different areas are developed, based on real-world vehicle activity data. The root mean square error (RMSE) is employed to quantify the difference between the VSP distributions. The maximum differences of the VSP distributions between different years and between different areas are approximately 20% of that between different road types. The analysis of the carbon dioxide (CO 2 ) emission factor indicates that the temporal and spatial differences of the VSP distributions have no significant impact on vehicle emission estimation, with relative error of less than 3%. The temporal and spatial differences have no significant impact on the development of the facility- and speed-specific VSP distributions for the vehicle emission estimation. The database of the specific VSP distributions in the VSP-based emission models can maintain in terms of time. Thus, it is unnecessary to update the database regularly, and it is reliable to use the history vehicle activity data to forecast the emissions in the future. In one city, the areas with less data can still

  17. Improving efficiency of two-type maximum power point tracking methods of tip-speed ratio and optimum torque in wind turbine system using a quantum neural network

    International Nuclear Information System (INIS)

    Ganjefar, Soheil; Ghassemi, Ali Akbar; Ahmadi, Mohamad Mehdi

    2014-01-01

    In this paper, a quantum neural network (QNN) is used as controller in the adaptive control structures to improve efficiency of the maximum power point tracking (MPPT) methods in the wind turbine system. For this purpose, direct and indirect adaptive control structures equipped with QNN are used in tip-speed ratio (TSR) and optimum torque (OT) MPPT methods. The proposed control schemes are evaluated through a battery-charging windmill system equipped with PMSG (permanent magnet synchronous generator) at a random wind speed to demonstrate transcendence of their effectiveness as compared to PID controller and conventional neural network controller (CNNC). - Highlights: • Using a new control method to harvest the maximum power from wind energy system. • Using an adaptive control scheme based on quantum neural network (QNN). • Improving of MPPT-TSR method by direct adaptive control scheme based on QNN. • Improving of MPPT-OT method by indirect adaptive control scheme based on QNN. • Using a windmill system based on PMSG to evaluate proposed control schemes

  18. Optimizing the wind power generation in low wind speed areas using an advanced hybrid RBF neural network coupled with the HGA-GSA optimization method

    Energy Technology Data Exchange (ETDEWEB)

    Assareh, Ehsanolah; Poultangari, Iman [Dezful Branch, Islamic Azad University, Dezful (Iran, Islamic Republic of); Tandis, Emad [Mechanical Engineering Department, University of Jundi Shapor, Dezful (Iran, Islamic Republic of); Nedael, Mojtaba [Dept. of Energy Engineering, Graduate School of the Environment and Energy, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2016-10-15

    Enhancing the energy production from wind power in low-wind areas has always been a fundamental subject of research in the field of wind energy industry. In the first phase of this research, an initial investigation was performed to evaluate the potential of wind in south west of Iran. The initial results indicate that the wind potential in the studied location is not sufficient enough and therefore the investigated region is identified as a low wind speed area. In the second part of this study, an advanced optimization model was presented to regulate the torque in the wind generators. For this primary purpose, the torque of wind turbine is adjusted using a Proportional and integral (PI) control system so that at lower speeds of the wind, the power generated by generator is enhanced significantly. The proposed model uses the RBF neural network to adjust the net obtained gains of the PI controller for the purpose of acquiring the utmost electricity which is produced through the generator. Furthermore, in order to edify and instruct the neural network, the optimal data set is obtained by a Hybrid genetic algorithm along with a gravitational search algorithm (HGA-GSA). The proposed method is evaluated by using a 5MW wind turbine manufactured by National Renewable Energy Laboratory (NREL). Final results of this study are indicative of the satisfactory and successful performance of the proposed investigated model.

  19. Effect of elastic band-based high-speed power training on cognitive function, physical performance and muscle strength in older women with mild cognitive impairment.

    Science.gov (United States)

    Yoon, Dong Hyun; Kang, Dongheon; Kim, Hee-Jae; Kim, Jin-Soo; Song, Han Sol; Song, Wook

    2017-05-01

    The effectiveness of resistance training in improving cognitive function in older adults is well demonstrated. In particular, unconventional high-speed resistance training can improve muscle power development. In the present study, the effectiveness of 12 weeks of elastic band-based high-speed power training (HSPT) was examined. Participants were randomly assigned into a HSPT group (n = 14, age 75.0 ± 0.9 years), a low-speed strength training (LSST) group (n = 9, age 76.0 ± 1.3 years) and a control group (CON; n = 7, age 78.0 ± 1.0 years). A 1-h exercise program was provided twice a week for 12 weeks for the HSPT and LSST groups, and balance and tone exercises were carried out by the CON group. Significant increases in levels of cognitive function, physical function, and muscle strength were observed in both the HSPT and LSST groups. In cognitive function, significant improvements in the Mini-Mental State Examination and Montreal Cognitive Assessment were seen in both the HSPT and LSST groups compared with the CON group. In physical functions, Short Physical Performance Battery scores were increased significantly in the HSPT and LSST groups compared with the CON group. In the 12 weeks of elastic band-based training, the HSPT group showed greater improvements in older women with mild cognitive impairment than the LSST group, although both regimens were effective in improving cognitive function, physical function and muscle strength. We conclude that elastic band-based HSPT, as compared with LSST, is more efficient in helping older women with mild cognitive impairment to improve cognitive function, physical performance and muscle strength. Geriatr Gerontol Int 2017; 17: 765-772. © 2016 Japan Geriatrics Society.

  20. A Low-Power High-Speed Spintronics-Based Neuromorphic Computing System Using Real Time Tracking Method

    DEFF Research Database (Denmark)

    Farkhani, Hooman; Tohidi, Mohammad; Farkhani, Sadaf

    2018-01-01

    In spintronic-based neuromorphic computing systems (NCS), the switching of magnetic moment in a magnetic tunnel junction (MTJ) is used to mimic neuron firing. However, the stochastic switching behavior of the MTJ and process variations effect lead to a significant increase in stimulation time...... of such NCSs. Moreover, current NCSs need an extra phase to read the MTJ state after stimulation which is in contrast with real neuron functionality in human body. In this paper, the read circuit is replaced with a proposed real-time sensing (RTS) circuit. The RTS circuit tracks the MTJ state during...... stimulation phase. As soon as switching happens, the RTS circuit terminates the MTJ current and stimulates the post neuron. Hence, the RTS circuit not only improves the energy consumption and speed, but also makes the operation of NCS similar to real neuron functionality. The simulation results in 65-nm CMOS...

  1. Realization of manchester encoding and decoding and fast-speed communication for digital power supply based on FPGA

    International Nuclear Information System (INIS)

    Chen Huanguang; Xu Ruinian; Shen Tianjian; Li Deming

    2008-01-01

    A design and simulation to realize the process of Manchester encoding and decoding, to realize the process of SPI communication between FPGA and DSP, using Altera company's Quartus II IDE on FPGA is presented in this paper. And the application on the digital power supply controller with Manchester communication by optical fiber is introduced. (authors)

  2. Reactor power control system

    International Nuclear Information System (INIS)

    Tomisawa, Teruaki.

    1981-01-01

    Purpose: To restore reactor-power condition in a minimum time after a termination of turbine bypass by reducing the throttling of the reactor power at the time of load-failure as low as possible. Constitution: The transient change of the internal pressure of condenser is continuously monitored. When a turbine is bypassed, a speed-control-command signal for a coolant recirculating pump is generated according as the internal pressure of the condenser. When the signal relating to the internal pressure of the condenser indicates insufficient power, a reactor-control-rod-drive signal is generated. (J.P.N.)

  3. Windage Power Loss in Gas Foil Bearings and the Rotor-Stator Clearance of High Speed Generators Operating in High Pressure Environments

    Science.gov (United States)

    Bruckner, Robert J.

    2009-01-01

    Closed Brayton Cycle (CBC) and Closed Supercritical Cycle (CSC) engines are prime candidates to convert heat from a reactor into electric power for robotic space exploration and habitation. These engine concepts incorporate a permanent magnet starter/generator mounted on the engine shaft along with the requisite turbomachinery. Successful completion of the long-duration missions currently anticipated for these engines will require designs that adequately address all losses within the machine. The preliminary thermal management concept for these engine types is to use the cycle working fluid to provide the required cooling. In addition to providing cooling, the working fluid will also serve as the bearing lubricant. Additional requirements, due to the unique application of these microturbines, are zero contamination of the working fluid and entirely maintenance-free operation for many years. Losses in the gas foil bearings and within the rotor-stator gap of the generator become increasingly important as both rotational speed and mean operating pressure are increased. This paper presents the results of an experimental study, which obtained direct torque measurements on gas foil bearings and generator rotor-stator gaps. Test conditions for these measurements included rotational speeds up to 42,000 revolutions per minute, pressures up to 45 atmospheres, and test gases of nitrogen, helium, and carbon dioxide. These conditions provided a maximum test Taylor number of nearly one million. The results show an exponential rise in power loss as mean operating density is increased for both the gas foil bearing and generator windage. These typical "secondary" losses can become larger than the total system output power if conventional design paradigms are followed. A nondimensional analysis is presented to extend the experimental results into the CSC range for the generator windage.

  4. Penetrating global consciousness: Art, killing as art, art as subversion, peace and the inversion of speed and power

    Directory of Open Access Journals (Sweden)

    Ian Liebenberg

    2015-12-01

    Full Text Available War chariots and armoured beasts of war played a major role in wars and influenced the outcomes of battles. The industrial era and age of total war saw new transmutations of this tool of war. When the first tanks rolled out at the battle of the Somme in September 1916, and a year later, an entire tank corps at Cambrai, a mobile tool of war was born that would weave itself deeply into battle space and global social consciousness, in fact humanity itself. Usually, the tank is viewed as the concrete manifestation of speed, mobility, all-round protection and firepower on the modern battlefield. It received attention in terms of design, armament and upgrades, as well as strategy and tactics. The tank redesigned battle space and impacted on national psyches and collective memory. Earmarked for killing, this object penetrated social consciousness, art, political discourse and issues of morality and peacemaking. This article reflects on the broader socio-economic, political and sociological outcomes of this invention. At a time of high technocracy, hyperglobalisation and transhumanity amidst increased global fragmentation, alienation, oppression and poverty, this tool still plays a problematic role. The tank constitutes a central component of the global industrial–military complex as much as it forms part of the (dis-fragmentation of current society and political discourse, it invokes critical reflection.

  5. Minimum Wages and Poverty

    OpenAIRE

    Fields, Gary S.; Kanbur, Ravi

    2005-01-01

    Textbook analysis tells us that in a competitive labor market, the introduction of a minimum wage above the competitive equilibrium wage will cause unemployment. This paper makes two contributions to the basic theory of the minimum wage. First, we analyze the effects of a higher minimum wage in terms of poverty rather than in terms of unemployment. Second, we extend the standard textbook model to allow for incomesharing between the employed and the unemployed. We find that there are situation...

  6. Development of a tornado wind speed hazard model for limited area (TOWLA) for nuclear power plants at a coastline

    International Nuclear Information System (INIS)

    Hirakuchi, Hiromaru; Nohara, Daisuke; Sugimoto, Soichiro; Eguchi, Yuzuru; Hattori, Yasuo

    2016-01-01

    It is necessary for Japanese electric power companies to assess tornado risks on the nuclear power plants according to a new regulation in 2013. The new regulatory guide recommends to select a long narrow strip area along a coast line with the width of 5 km to the seaward and landward sides as a target area of tornado risk assessment, because most of Japanese tornados have been reported near the coast line, where all of Japanese nuclear power plants are located. However, it is very difficult to evaluate a tornado hazard along a coast line, because there is no available information of F-scale and damage length/width on tornadic waterspouts. The purpose of this study is to propose a new tornado wind hazard model for limited area (TOWLA), which can be apply to a long narrow strip area along a coastline. In order to consider tornadic waterspouts moved inland, we evaluate the number of waterspouts entering/passing the targeting area, and add them to the total number of the tornado occurred in the area. A characteristic of the model is to use 'segment lengths' instead of damage lengths. The segment length is a part of the tornado foot print in the long narrow strip area. We show two methods for segment length computation. One is based on tornado records; latitude and longitude of tornado genesis and dissipation locations. The other is to compute the expected segment length based on the geometrical relationship among the damage length, area width, and directional characteristics of tornado movement. The new model can also consider the variation of tornado intensity along the path length and across the path width. (author)

  7. Prior exercise speeds pulmonary oxygen uptake kinetics and increases critical power during supine but not upright cycling.

    Science.gov (United States)

    Goulding, Richie P; Roche, Denise M; Marwood, Simon

    2017-09-01

    What is the central question of this study? Critical power (CP) represents the highest work rate for which a metabolic steady state is attainable. The physiological determinants of CP are unclear, but research suggests that CP might be related to the time constant of phase II oxygen uptake kinetics (τV̇O2). What is the main finding and its importance? We provide the first evidence that τV̇O2 is mechanistically related to CP. A reduction of τV̇O2 in the supine position was observed alongside a concomitant increase in CP. This effect may be contingent on measures of oxygen availability derived from near-infrared spectroscopy. Critical power (CP) is a fundamental parameter defining high-intensity exercise tolerance and is related to the time constant of phase II pulmonary oxygen uptake kinetics (τV̇O2). To test the hypothesis that this relationship is causal, we determined the impact of prior exercise ('priming') on CP and τV̇O2 in the upright and supine positions. Seventeen healthy men were assigned to either upright or supine exercise groups, whereby CP, τV̇O2 and muscle deoxyhaemoglobin kinetics (τ [HHb] ) were determined via constant-power tests to exhaustion at four work rates with (primed) and without (control) priming exercise at ∼31%Δ. During supine exercise, priming reduced τV̇O2 (control 54 ± 18 s versus primed 39 ± 11 s; P exercise had no effect on τV̇O2 (control 37 ± 12 s versus primed 35 ± 8 s; P = 0.82), τ [HHb] (control 10 ± 5 s versus primed 14 ± 10 s; P = 0.10) or CP (control 235 ± 42 W versus primed 232 ± 35 W; P = 0.57) during upright exercise. The concomitant reduction of τV̇O2 and increased CP following priming in the supine group, effects that were absent in the upright group, provide the first experimental evidence that τV̇O2 is mechanistically related to critical power. The increased τ [HHb+Mb] suggests that this effect was mediated, at least in part, by improved oxygen

  8. The Impacts of Wind Speed Trends and 30-Year Variability in Relation to Hydroelectric Reservoir Inflows on Wind Power in the Pacific Northwest.

    Science.gov (United States)

    Cross, Benjamin D; Kohfeld, Karen E; Bailey, Joseph; Cooper, Andrew B

    2015-01-01

    In hydroelectric dominated systems, the value and benefits of energy are higher during extended dry periods and lower during extended or extreme wet periods. By accounting for regional and temporal differences in the relationship between wind speed and reservoir inflow behavior during wind farm site selection, the benefits of energy diversification can be maximized. The goal of this work was to help maximize the value of wind power by quantifying the long-term (30-year) relationships between wind speed and streamflow behavior, using British Columbia (BC) and the Pacific Northwest (PNW) as a case study. Clean energy and self-sufficiency policies in British BC make the benefits of increased generation during low streamflow periods particularly large. Wind density (WD) estimates from a height of 10m (North American Regional Reanalysis, NARR) were correlated with cumulative usable inflows (CUI) for BC (collected from BC Hydro) for 1979-2010. The strongest WD-CUI correlations were found along the US coast (r ~0.55), whereas generally weaker correlations were found in northern regions, with negative correlations (r ~ -0.25) along BC's North Coast. Furthermore, during the lowest inflow years, WD anomalies increased by up to 40% above average values for the North Coast. Seasonally, high flows during the spring freshet were coincident with widespread negative WD anomalies, with a similar but opposite pattern for low inflow winter months. These poorly or negatively correlated sites could have a moderating influence on climate related variability in provincial electricity supply, by producing greater than average generation in low inflow years and reduced generation in wet years. Wind speed and WD trends were also analyzed for all NARR grid locations, which showed statistically significant positive trends for most of the PNW and the largest increases along the Pacific Coast.

  9. Fuel saving and emissions cut through shore-side power concept for high-speed crafts at the red sea in egypt

    Science.gov (United States)

    Seddiek, Ibrahim S.; Mosleh, Mosaad A.; Banawan, Adel A.

    2013-12-01

    The progress of economic globalization, the rapid growth of international trade, and the maritime transportation has played an increasingly significant role in the international supply chain. As a result, worldwide seaports have suffered from a central problem, which appears in the form of massive amounts of fuel consumed and exhaust gas fumes emitted from the ships while berthed. Many ports have taken the necessary precautions to overcome this problem, while others still suffer due to the presence of technical and financial constraints. In this paper, the barriers, interconnection standards, rules, regulations, power sources, and economic and environmental analysis related to ships, shore-side power were studied in efforts to find a solution to overcome his problem. As a case study, this paper investigates the practicability, costs and benefits of switching from onboard ship auxiliary engines to shore-side power connection for high-speed crafts called Alkahera while berthed at the port of Safaga, Egypt. The results provide the national electricity grid concept as the best economical selection with 49.03 percent of annual cost saving. Moreover, environmentally, it could achieve an annual reduction in exhaust gas emissions of CO2, CO, NO x , P.M, and SO2 by 276, 2.32, 18.87, 0.825 and 3.84 tons, respectively.

  10. A rational method to evaluate tornado-borne missile speed in nuclear power plants. Validation of a numerical code based on Fujita's tornado model

    International Nuclear Information System (INIS)

    Eguchi, Yuzuru; Sugimoto, Soichiro; Hattori, Yasuo; Hirakuchi, Hiromaru

    2015-01-01

    Explanation is given about a rational method to evaluate tornado-borne missile speed, flight distance and flight height to be used for safety design of a nuclear power plant. In the method, the authors employed Fujita's DBT-77 model as a tornado wind model to take the near-ground tornado wind profile into account. A liftoff model of an object on the ground was developed by conservatively modeling the lift force due to ground effect. The wind field model and the liftoff model have been compiled together with a conventional flight model into a computer code, named TONBOS. In this study, especially, the code is verified for one- and two-dimensional free-fall problems as well as a case of 1957 Dallas tornado wind field model, whose solutions are theoretically or numerically known. Finally, the code is validated by typical car behaviors characterized by tornado wind speeds of the enhanced Fujita scale, as well as by an actual event where a truck was blown away by a tornado which struck a part of the town of Saroma, Hokkaido in November, 2006. (author)

  11. Book Review: Lumea cu Două Viteze. Puterile Emergente şi Țările Dezvoltate (Two-Speed World: Emerging Powers and Developed Countries

    Directory of Open Access Journals (Sweden)

    Bogdan Mureşan

    2015-09-01

    Full Text Available This review analyses Paul Dobrescu’s ‘Two-Speed World: Emerging Powers and Developed Countries’, a brief volume made up of a collection of articles on various international relations and European affairs topics initially published by the Romanian professor in the “CLIPA” magazine in the 2010-2013 timeframe. Although sometimes lacking narrative consistency, the book emphasises the idea that the world in which we find ourselves is one with two speeds of development, characterised by a shifting centre of gravity from the West to the East, a tendency especially highlighted by the first decade of this century. By asking if the next century is going to be a Western one and if the European Union project, deeply hurt by the financial crisis, still has a future, Paul Dobrescu challenges his readers to think outside the box and paints a rather grim picture of things to come, with a society dominated by consumerism and a shortage in morality.

  12. Speed control at low wind speeds for a variable speed fixed pitch wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Rosmin, N.; Watson, S.J.; Tompson, M. [Loughborough Univ., Loughborough, Leicestershire (United Kingdom)

    2010-03-09

    The maximum power regulation below rated wind speed is regulated by changing the rotor/generator speed at large frequency range in a fixed pitch, variable speed, stall-regulated wind turbine. In order to capture the power at a maximum value the power coefficient is kept at maximum peak point by maintaining the tip speed ratio at its optimum value. The wind industry is moving from stall regulated fixed speed wind turbines to newer improved innovative versions with better reliability. While a stall regulated fixed pitch wind turbine is among the most cost-effective wind turbine on the market, its problems include noise, severe vibrations, high thrust loads and low power efficiency. Therefore, in order to improve such drawbacks, the rotation of the generator speed is made flexible where the rotation can be controlled in variable speed. This paper discussed the development of a simulation model which represented the behaviour of a stall regulated variable speed wind turbine at low wind speed control region by using the closed loop scalar control with adjustable speed drive. The paper provided a description of each sub-model in the wind turbine system and described the scalar control of the induction machine. It was concluded that by using a constant voltage/frequency ratio of the generator's stator side control, the generator speed could be regulated and the generator torque could be controlled to ensure the power coefficient could be maintained close to its maximum value. 38 refs., 1 tab., 10 figs.

  13. High sensitivity, fast speed and self-powered ultraviolet photodetectors based on ZnO micro/nanowire networks

    Directory of Open Access Journals (Sweden)

    Zhiming Bai

    2014-02-01

    Full Text Available Ultraviolet (UV photodetectors (PDs based on ZnO micro/nanowire (MNW networks with Pt contacts have been fabricated on glass substrates. The PDs exhibited a high photosensitivity (5×103 for 365 nm UV light with a fast recovery time (0.2 s at a reverse bias voltage of 2 V. The light induced modulation of Schottky barrier and MNW–MNW junction barrier was employed to account for the results. It was also observed that the PD had a high on–off ratio of 800 without external bias. The photovoltaic effect was proposed to explain the self-powered phenomenon.

  14. Effect of operating methods of wind turbine-generator system on net power extraction under wind speed fluctuations in fields; Hendo fukyoka deno doryoku chushutsu kara mita furyoku hatsuden system no unten seigyoho ni kansuru kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Wakui, T. [Japan Society for the Promotion of Science, Tokyo (Japan); Hashizume, T.; Ota, E. [Waseda University, Tokyo (Japan). School of Science and Engineering

    2000-01-25

    The effect of operating methods of wind turbine-generator system on net power extraction under wind speed fluctuations is discussed in relation to the dynamic behavior of the system. The system is composed of a Darrieus-Savonius hybrid wind turbine and a load generator. In this paper, two types of operating method are examined; constant tip speed ratio operation for stand-alone power systems (Scheme 1) and synchronous operation for utility power systems (Scheme 2). The computed results of the net extracting power using our dynamic simulation model show that the dominant factor of power extraction in Scheme 1 is the dynamic characteristics of rotational components and that it is important to select the appropriate rated wind speed in Scheme 2. Thus, it is concluded that a conformable operating method and rated power output of the system exist for each wind condition. In particular, small-scale systems, which are smaller than approximately 10 kW-system range, are desirable to be operated under a constant tip speed ratio as stand-alone power systems. (author)

  15. High speed heterostructure devices

    CERN Document Server

    Beer, Albert C; Willardson, R K; Kiehl, Richard A; Sollner, T C L Gerhard

    1994-01-01

    Volume 41 includes an in-depth review of the most important, high-speed switches made with heterojunction technology. This volume is aimed at the graduate student or working researcher who needs a broad overview andan introduction to current literature. Key Features * The first complete review of InP-based HFETs and complementary HFETs, which promise very low power and high speed * Offers a complete, three-chapter review of resonant tunneling * Provides an emphasis on circuits as well as devices.

  16. Ref Tek Ultra-low Power Seismic Recorder With Low-cost High Speed Internet Telemetry U An Advanced Real-time Seismological Data Acquisition System

    Science.gov (United States)

    Passmore, P.; Zimakov, L.; Rozhkov, M.

    The 3rd Generation Seismic Recorder, Model 130-01, has been designed to be easier to use - more compact, lighter in weight, lower power, and requires less maintenance than other recorders. Not only is the hardware optimized for field deployments, soft- ware tools as well have been specially developed to support both field and base station operation. The 130's case is a clamshell design, inherently waterproof, with easy access to all user features on the top of the unit. The 130 has 6 input/output connectors, an LCD display, and a removable lid on top of the case. There are two Channel input connectors on a 6-channel unit (only one on a 3-channel unit), a Terminal connector for setup and control, a Net connector combining Ethernet and Serial PPP for network access, a 12 VDC Power connector, and a GPS receiver connector. The LCD display allows the user to monitor the status of various sub systems within the 130 without having a terminal device attached. For storing large amounts of data the IBM MicrodriveTM is offered. User setup, control and status monitoring is done either with a Personal Digital Assistant (PDA) (Palm OS compatible) using our Palm Field Controller (PFC) software or from a PC/workstation using our REF TEK Network Controller (RNC) GUI interface. StarBand VSAT is the premier two-way, always-on, high-speed satellite Internet ser- vice. StarBand means high-speed Internet without the constraints and congestion of land-based cable or telephone networks. StarBand uses a single satellite dish antenna for receiving and for sending dataUno telephone connection is needed. The hardware ° cost is much less than standard VSAT equipment with double or single hop transmis- sion. REF TEK protocol (RTP) provides end-to-end error-correcting data transmission and command/control. StarBandSs low cost VSAT provides two-way, always-on, high speed satellite Internet data availability. REF TEK and StarBand create the most ad- vanced real-time seismological data acquisition

  17. High-speed AC motors

    Energy Technology Data Exchange (ETDEWEB)

    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.

  18. On the speed of response of an FPGA-based shutdown system in CANDU nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    She Jingke, E-mail: jshe2@uwo.ca [Department of Electrical and Computer Engineering, The University of Western Ontario, London, Ontario, N6A 5B9 (Canada); Jiang Jin, E-mail: jjiang@eng.uwo.ca [Department of Electrical and Computer Engineering, The University of Western Ontario, London, Ontario, N6A 5B9 (Canada)

    2011-06-15

    Highlights: > Design and implementation of an FPGA-based CANDU SDS1. > Hardware-in-the-loop simulation for performance evaluation involved with an NPP simulator. > Comparison of the response time between FPGA-based trip channel and software-based PLC. - Abstract: Several issues in an FPGA based implementation of shutdown systems in CANDU nuclear power plants have been investigated in this paper. A particular attention is on the response time of an FPGA implementation of safety shutdown systems in comparison with operating system based software solutions as in existing CANDU plants. The trip decision logic under 'steam generator (SG) level low' condition has been examined in detail. The design and implementation of this logic on an FPGA platform have been carried out. The functionality tests are performed in a hardware-in-the-loop (HIL) environment by connecting the FPGA based system to an NPP simulator, and replacing one channel of Shutdown System Number 1 (SDS1) in the simulator by the FPGA implementation. The response time of the designed system is also measured through multiple tests under different conditions, and statistical data analysis has been performed. The results of the response time tests are compared against those of a software-based implementation of the same trip logic.

  19. The effect of heavy- vs. light-load jump squats on the development of strength, power, and speed.

    Science.gov (United States)

    McBride, Jeffrey M; Triplett-McBride, Travis; Davie, Allan; Newton, Robert U

    2002-02-01

    The purpose of this investigation was to examine the effect of an 8-week training program with heavy- vs. light-load jump squats on various physical performance measures and electromyography (EMG). Twenty-six athletic men with varying levels of resistance training experience performed sessions of jump squats with either 30% (JS30, n = 9) or 80% (JS80, n = 10) of their one repetition maximum in the squat (1RM) or served as a control (C, n = 7). An agility test, 20-m sprint, and jump squats with 30% (30J), 55% (55J), and 80% (80J) of their 1RM were performed before and after training. Peak force, peak velocity (PV), peak power (PP), jump height, and average EMG (concentric phase) were calculated for the jumps. There were significant increases in PP and PV in the 30J, 55J, and 80J for the JS30 group (p squats results in increased movement velocity capabilities and that velocity-specific changes in muscle activity may play a key role in this adaptation.

  20. Minimum critical mass systems

    International Nuclear Information System (INIS)

    Dam, H. van; Leege, P.F.A. de

    1987-01-01

    An analysis is presented of thermal systems with minimum critical mass, based on the use of materials with optimum neutron moderating and reflecting properties. The optimum fissile material distributions in the systems are obtained by calculations with standard computer codes, extended with a routine for flat fuel importance search. It is shown that in the minimum critical mass configuration a considerable part of the fuel is positioned in the reflector region. For 239 Pu a minimum critical mass of 87 g is found, which is the lowest value reported hitherto. (author)

  1. Minimum Thrust Load Control for Floating Wind Turbine

    DEFF Research Database (Denmark)

    Christiansen, Søren; Bak, Thomas; Knudsen, Torben

    2012-01-01

    — Offshore wind energy capitalizes on the higher and less turbulent wind at sea. Shallow water sites are profitable for deployment of monopile wind turbines at water depths of up to 30 meters. Beyond 30 meters, the wind is even stronger and less turbulent. At these depths, floating wind turbines be...... and power stability when using the new control strategy.......— Offshore wind energy capitalizes on the higher and less turbulent wind at sea. Shallow water sites are profitable for deployment of monopile wind turbines at water depths of up to 30 meters. Beyond 30 meters, the wind is even stronger and less turbulent. At these depths, floating wind turbines...... presents a new minimum thrust control strategy capable of stabilizing a floating wind turbine. The new control strategy explores the freedom of variable generator speed above rated wind speed. A comparison to the traditional constant speed strategy, shows improvements in structural fore-aft oscillations...

  2. Minimum entropy production principle

    Czech Academy of Sciences Publication Activity Database

    Maes, C.; Netočný, Karel

    2013-01-01

    Roč. 8, č. 7 (2013), s. 9664-9677 ISSN 1941-6016 Institutional support: RVO:68378271 Keywords : MINEP Subject RIV: BE - Theoretical Physics http://www.scholarpedia.org/article/Minimum_entropy_production_principle

  3. Probabilistic assessment of tornado-borne missile speeds. Final report

    International Nuclear Information System (INIS)

    Simiu, E.; Cordes, M.R.

    1980-09-01

    A procedure was developed for estimating speeds with which postulated missiles hit any given set of targets in a nuclear power plant or similar installation. Hit speeds corresponding to probabilities of occurrence of .0000001 were calculated for a given nuclear power plant under various assumptions concerning the magnitude of the force opposing missile take-off, direction of tornado axis of translation, number and location of missiles, and size of target area. The results of the calculations are shown to depend upon the parameters: CDA/m, where CD = drag coefficient, A = projected area, m = mass of missiles, and the ratio, k, between the minimum aerodynamic force required to cause missile take-off, and the weight of the missile

  4. Fuzzy controller of speed-power of a synchronous micro generator; Controlador difuso de velocidad-potencia de un microgenerador sincrono

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Alvarado, Raziel

    2002-11-01

    This thesis shows the design and implementation of a speed-power fuzzy-logic controller. The controller implementation was carried out on the Schrage motor-synchronous generator set. The synchronous alternator is rated 7 kVA, 220 V, 1800 rpm, 60 Hz. Two PI like fuzzy-logic controllers were developed with 9 and 25 rules. The controllers use the speed or power error and its integral as input variables and as an output the control signal from the brush-positioner of the Schrage motor. At the controller design stage, the anfis (adaptive-network-based fuzzy inference system) learning and structure procedure was used for tuning up parameters of the membership functions used on the designed fuzzy controllers. These controllers are first-order Sugeno-type. The designed controllers were tested on the motor-generator set under loaded and no-loaded conditions. It was found that PI-9 rules fuzzy-logic controller had better performance on both operating conditions. [Spanish] En este trabajo de tesis se presenta el diseno e implementacion de un controlador difuso de velocidad-potencia, para un grupo motor Schrage-generador sincrono de 7 kVA, 220 V, 1800 rpm, 60 Hz. Se implementaron controladores difusos del tipo PI de 9 y 25 reglas. Estos controladores utilizan como variables de entrada el error y la integral del error, de velocidad o potencia segun corresponda, y como variable de salida la senal de control del posicionador de las escobillas del motor Schrage. En la etapa de diseno de los controladores, se utilizo la estructura y el procedimiento de aprendizaje anfis (Sistema de Inferencia Difuso Basado en Redes Adaptables, por sus siglas en ingles) para sintonizar los parametros de las funciones de membresia de los controladores difusos, los cuales son del tipo Sugeno de primer orden. Con la finalidad de validar los controladores disenados, se realizaron pruebas experimentales al grupo motor-generador en condiciones de vacio y carga. Se encontro que el controlador difuso tipo

  5. 14 CFR 23.149 - Minimum control speed.

    Science.gov (United States)

    2010-01-01

    ... not more than 5 degrees. The method used to simulate critical engine failure must represent the most critical mode of powerplant failure expected in service with respect to controllability. (b) VMC for... the critical engine is made inoperative to the point at which recovery to a direction parallel to the...

  6. Changes of the level of high-speed and power abilities of beach handball players of 14–15 years old as a result of the specially selective exercises

    Directory of Open Access Journals (Sweden)

    Helena Biykova

    2015-12-01

    Full Text Available Purpose: to determine changes of the level of high-speed and power abilities of beach handball players of 14–15 years old under the influence of the specially selective sets of exercises. Material and Methods: test exercises, one of which is recommended by the training program of CYSS of beach handball, two others were created proceeding from the content of the game activity in beach handball, the analysis of scientific and methodical literature, pedagogical testing, pedagogical experiment, methods of mathematical information processing were used for the definition of the level of development of high-speed and power abilities of beach handball players. Results: the analysis of scientific and methodical literature revealed gaps in questions of training of beach handball players, in particular in physical preparation. It moved us making the use of experience of the educational and training work in beach volleyball, to make sets of exercises, which are aimed at the development high-speed and power abilities of beach handball players. Conclusions: the positive reliable changes are received (t=2,19–2,32 at p≤0,05 of the level of high-speed and power abilities of players of 14-15 years old under the influence of the sets of exercises which are offered by us, allows us to recommend them for use in the educational and training process of beach handball players

  7. Near-Threshold Computing and Minimum Supply Voltage of Single-Rail MCML Circuits

    Directory of Open Access Journals (Sweden)

    Ruiping Cao

    2014-01-01

    Full Text Available In high-speed applications, MOS current mode logic (MCML is a good alternative. Scaling down supply voltage of the MCML circuits can achieve low power-delay product (PDP. However, the current almost all MCML circuits are realized with dual-rail scheme, where the NMOS configuration in series limits the minimum supply voltage. In this paper, single-rail MCML (SRMCML circuits are described, which can avoid the devices configuration in series, since their logic evaluation block can be realized by only using MOS devices in parallel. The relationship between the minimum supply voltage of the SRMCML circuits and the model parameters of MOS transistors is derived, so that the minimum supply voltage can be estimated before circuit designs. An MCML dynamic flop-flop based on SRMCML is also proposed. The optimization algorithm for near-threshold sequential circuits is presented. A near-threshold SRMCML mode-10 counter based on the optimization algorithm is verified. Scaling down the supply voltage of the SRMCML circuits is also investigated. The power dissipation, delay, and power-delay products of these circuits are carried out. The results show that the near-threshold SRMCML circuits can obtain low delay and small power-delay product.

  8. Speed mathematics

    CERN Document Server

    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

  9. On control strategies for power optimization and regulation of variable speed wind turbines; Sur les strategies de commande pour l'optimisation et la regulation de puissance des eoliennes a vitesse variable

    Energy Technology Data Exchange (ETDEWEB)

    Boukhezzar, B

    2006-02-15

    The research work is dealing with variable speed wind turbines modelling and control design, in order to achieve the objectives of maximizing the extracted energy from the wind, below the rated power area in the one hand and in the other hand regulating the electric power production, above the rated power area, while reducing mechanical transient loads. For this purpose, we have studied various control strategies from linear to nonlinear based. some of the controllers that we have developed, herein appear for the first time in the relevant domain, the remaining others are an adaptation of well know controllers to the adopted wind turbine models. as matter of fact, we have derived two wind turbine models as well as a wind speed estimator. Indeed, the estimator allows obtaining the effective wind speed which cannot be measured, since the wind profile around the rotor is variable in time and space. As results, it has been shown that single input control by means of pitch angle or generator control cannot succeed to simultaneously drive the electric power output regulation and the rotor speed reference tracking. So then, our idea is to combine nonlinear dynamic state feedback torque control and pitch linear based control which turns out to be the best strategy. In addition, the validation of the controllers performance, using a high turbulence wind speed profile, has been performed through wind turbine simulators provided by nrel (national renewable energy laboratory, golden, co), has confirmed the theoretical results and has led to quite satisfactory conclusions in terms of energy capture optimization, power regulation and disturbances strong rejection as well. (author)

  10. Capacitated Vehicle Routing with Nonuniform Speeds

    DEFF Research Database (Denmark)

    Gørtz, Inge Li; Molinaro, Marco; Nagarajan, Viswanath

    2016-01-01

    is the distance traveled divided by its speed.Our algorithm relies on a new approximate minimum spanning tree construction called Level-Prim, which is related to but different from Light Approximate Shortest-path Trees. We also extend the widely used tour-splitting technique to nonuniform speeds, using ideas from...

  11. Assessment of C-Type Darrieus Wind Turbine Under Low Wind Speed Condition

    Science.gov (United States)

    Misaran, M. S.; Rahman, Md. M.; Muzammil, W. K.; Ismail, M. A.

    2017-07-01

    Harvesting wind energy in in a low wind speed region is deem un-economical if not daunting task. Study shows that a minimum cut in speed of 3.5 m/s is required to extract a meaningful wind energy for electricity while a mean speed of 6 m/s is preferred. However, in Malaysia the mean speed is at 2 m/s with certain potential areas having 3 m/s mean speed. Thus, this work aims to develop a wind turbine that able to operate at lower cut-in speed and produce meaningful power for electricity generation. A C-type Darrieus blade is selected as it shows good potential to operate in arbitrary wind speed condition. The wind turbine is designed and fabricated in UMS labs while the performance of the wind turbine is evaluated in a simulated wind condition. Test result shows that the wind turbine started to rotate at 1 m/s compared to a NACA 0012 Darrieus turbine that started to rotate at 3 m/s. The performance of the turbine shows that it have good potential to be used in an intermittent arbitrary wind speed condition as well as low mean wind speed condition.

  12. NTF – wind speed comparison

    DEFF Research Database (Denmark)

    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...

  13. Power system observability with minimum phasor measurement ...

    African Journals Online (AJOL)

    user

    Due to the high cost of having a PMU at each node, some of the studies performed in ..... through the process of expanding, which makes the observational topologies, ...... FACTS controllers”, International Journal of Engineering, Science and ...

  14. Effect of water injection and off scheduling of variable inlet guide vanes, gas generator speed and power turbine nozzle angle on the performance of an automotive gas turbine engine

    Science.gov (United States)

    Warren, E. L.

    1980-01-01

    The Chrysler/ERDA baseline automotive gas turbine engine was used to experimentally determine the power augmentation and emissions reductions achieved by the effect of variable compressor and power engine geometry, water injection downstream of the compressor, and increases in gas generator speed. Results were dependent on the mode of variable geometry utilization. Over 20 percent increase in power was accompanied by over 5 percent reduction in SFC. A fuel economy improvement of at least 6 percent was estimated for a vehicle with a 75 kW (100 hp) engine which could be augmented to 89 kW (120 hp) relative to an 89 Kw (120 hp) unaugmented engine.

  15. Speed checks on the CERN site

    CERN Multimedia

    2007-01-01

    In view of the significant number of speeding incidents that have been reported, CERN will shortly start to carry out speed checks on the site. The radar used for this purpose will show drivers the speed measured. The disciplinary measures taken against those exceeding the authorised limit (generally 50 k.p.h.) will include a ban from driving on the site for a minimum of one month. Maximilian Metzger
Secretary-General

  16. Rising above the Minimum Wage.

    Science.gov (United States)

    Even, William; Macpherson, David

    An in-depth analysis was made of how quickly most people move up the wage scale from minimum wage, what factors influence their progress, and how minimum wage increases affect wage growth above the minimum. Very few workers remain at the minimum wage over the long run, according to this study of data drawn from the 1977-78 May Current Population…

  17. Analyzing Power Supply and Demand on the ISS

    Science.gov (United States)

    Thomas, Justin; Pham, Tho; Halyard, Raymond; Conwell, Steve

    2006-01-01

    Station Power and Energy Evaluation Determiner (SPEED) is a Java application program for analyzing the supply and demand aspects of the electrical power system of the International Space Station (ISS). SPEED can be executed on any computer that supports version 1.4 or a subsequent version of the Java Runtime Environment. SPEED includes an analysis module, denoted the Simplified Battery Solar Array Model, which is a simplified engineering model of the ISS primary power system. This simplified model makes it possible to perform analyses quickly. SPEED also includes a user-friendly graphical-interface module, an input file system, a parameter-configuration module, an analysis-configuration-management subsystem, and an output subsystem. SPEED responds to input information on trajectory, shadowing, attitude, and pointing in either a state-of-charge mode or a power-availability mode. In the state-of-charge mode, SPEED calculates battery state-of-charge profiles, given a time-varying power-load profile. In the power-availability mode, SPEED determines the time-varying total available solar array and/or battery power output, given a minimum allowable battery state of charge.

  18. 一种风电机组在低风速区间的功率控制方法%A power control method of wind turbines in low wind speed area

    Institute of Scientific and Technical Information of China (English)

    张安安; 郭红鼎; 于兵; 李楠; 李超

    2015-01-01

    由于在低风速区间风速变化较快、风能密度较低,因此对风电机组的功率转换效率造成了较大影响。针对风电机组在低风速区域的运行特点,从功率控制角度出发,以提高风电机组功率输出效率为目的,采用最大功率点跟踪控制策略(MPPT)实现对风能最大限度的捕获,提出了大范围快速对焦最优转速的控制策略。与传统爬山法相比,该方法具有寻优速度快、精确度高、简单易行的优点。在Power Simulation(PSIM)环境中仿真分析,研究结果表明:该控制策略对提高机组稳定性和功率转换效率具有一定的价值。%Wind velocity alters rapidly and the density of wind energy is lower in low wind speed area, which greatly affect power conversion efficiency of wind turbines. Aimed at enhancing wind turbines efficiency of power output, MPPT is adopted to capture maximum wind power from the perspective of power control according to operating peculiarity of wind turbine in low wind speed area. On the basis, a control strategy of fast focusing optimal rotating speed in wide range is simple, highly accurate and quicker to achieve optimal solution compared with conventional climbing method. Simulation in Power Simulation (PSIM) shows that this control strategy has a certain value for improving wind turbine stability and power conversion efficiency.

  19. Minimum Error Entropy Classification

    CERN Document Server

    Marques de Sá, Joaquim P; Santos, Jorge M F; Alexandre, Luís A

    2013-01-01

    This book explains the minimum error entropy (MEE) concept applied to data classification machines. Theoretical results on the inner workings of the MEE concept, in its application to solving a variety of classification problems, are presented in the wider realm of risk functionals. Researchers and practitioners also find in the book a detailed presentation of practical data classifiers using MEE. These include multi‐layer perceptrons, recurrent neural networks, complexvalued neural networks, modular neural networks, and decision trees. A clustering algorithm using a MEE‐like concept is also presented. Examples, tests, evaluation experiments and comparison with similar machines using classic approaches, complement the descriptions.

  20. Aerodynamic Effects of Turbulence Intensity on a Variable-Speed Power-Turbine Blade with Large Incidence and Reynolds Number Variations

    Science.gov (United States)

    Flegel, Ashlie Brynn; Giel, Paul W.; Welch, Gerard E.

    2014-01-01

    The effects of inlet turbulence intensity on the aerodynamic performance of a variable speed power turbine blade are examined over large incidence and Reynolds number ranges. Both high and low turbulence studies were conducted in the NASA Glenn Research Center Transonic Turbine Blade Cascade Facility. The purpose of the low inlet turbulence study was to examine the transitional flow effects that are anticipated at cruise Reynolds numbers. The high turbulence study extends this to LPT-relevant turbulence levels while perhaps sacrificing transitional flow effects. Downstream total pressure and exit angle data were acquired for ten incidence angles ranging from +15.8 to 51.0. For each incidence angle, data were obtained at five flow conditions with the exit Reynolds number ranging from 2.12105 to 2.12106 and at a design exit Mach number of 0.72. In order to achieve the lowest Reynolds number, the exit Mach number was reduced to 0.35 due to facility constraints. The inlet turbulence intensity, Tu, was measured using a single-wire hotwire located 0.415 axial-chord upstream of the blade row. The inlet turbulence levels ranged from 0.25 - 0.4 for the low Tu tests and 8- 15 for the high Tu study. Tu measurements were also made farther upstream so that turbulence decay rates could be calculated as needed for computational inlet boundary conditions. Downstream flow field measurements were obtained using a pneumatic five-hole pitchyaw probe located in a survey plane 7 axial chord aft of the blade trailing edge and covering three blade passages. Blade and endwall static pressures were acquired for each flow condition as well. The blade loading data show that the suction surface separation that was evident at many of the low Tu conditions has been eliminated. At the extreme positive and negative incidence angles, the data show substantial differences in the exit flow field. These differences are attributable to both the higher inlet Tu directly and to the thinner inlet endwall

  1. Aerodynamic Effects of High Turbulence Intensity on a Variable-Speed Power-Turbine Blade With Large Incidence and Reynolds Number Variations

    Science.gov (United States)

    Flegel, Ashlie B.; Giel, Paul W.; Welch, Gerard E.

    2014-01-01

    The effects of high inlet turbulence intensity on the aerodynamic performance of a variable speed power turbine blade are examined over large incidence and Reynolds number ranges. These results are compared to previous measurements made in a low turbulence environment. Both high and low turbulence studies were conducted in the NASA Glenn Research Center Transonic Turbine Blade Cascade Facility. The purpose of the low inlet turbulence study was to examine the transitional flow effects that are anticipated at cruise Reynolds numbers. The current study extends this to LPT-relevant turbulence levels while perhaps sacrificing transitional flow effects. Assessing the effects of turbulence at these large incidence and Reynolds number variations complements the existing database. Downstream total pressure and exit angle data were acquired for 10 incidence angles ranging from +15.8deg to -51.0deg. For each incidence angle, data were obtained at five flow conditions with the exit Reynolds number ranging from 2.12×10(exp 5) to 2.12×10(exp 6) and at a design exit Mach number of 0.72. In order to achieve the lowest Reynolds number, the exit Mach number was reduced to 0.35 due to facility constraints. The inlet turbulence intensity, Tu, was measured using a single-wire hotwire located 0.415 axial-chord upstream of the blade row. The inlet turbulence levels ranged from 8 to 15 percent for the current study. Tu measurements were also made farther upstream so that turbulence decay rates could be calculated as needed for computational inlet boundary conditions. Downstream flow field measurements were obtained using a pneumatic five-hole pitch/yaw probe located in a survey plane 7 percent axial chord aft of the blade trailing edge and covering three blade passages. Blade and endwall static pressures were acquired for each flow condition as well. The blade loading data show that the suction surface separation that was evident at many of the low Tu conditions has been eliminated. At

  2. Do Minimum Wages Fight Poverty?

    OpenAIRE

    David Neumark; William Wascher

    1997-01-01

    The primary goal of a national minimum wage floor is to raise the incomes of poor or near-poor families with members in the work force. However, estimates of employment effects of minimum wages tell us little about whether minimum wages are can achieve this goal; even if the disemployment effects of minimum wages are modest, minimum wage increases could result in net income losses for poor families. We present evidence on the effects of minimum wages on family incomes from matched March CPS s...

  3. High-speed parallel counter

    International Nuclear Information System (INIS)

    Gus'kov, B.N.; Kalinnikov, V.A.; Krastev, V.R.; Maksimov, A.N.; Nikityuk, N.M.

    1985-01-01

    This paper describes a high-speed parallel counter that contains 31 inputs and 15 outputs and is implemented by integrated circuits of series 500. The counter is designed for fast sampling of events according to the number of particles that pass simultaneously through the hodoscopic plane of the detector. The minimum delay of the output signals relative to the input is 43 nsec. The duration of the output signals can be varied from 75 to 120 nsec

  4. Minimum qualifications for nuclear criticality safety professionals

    International Nuclear Information System (INIS)

    Ketzlach, N.

    1990-01-01

    A Nuclear Criticality Technology and Safety Training Committee has been established within the U.S. Department of Energy (DOE) Nuclear Criticality Safety and Technology Project to review and, if necessary, develop standards for the training of personnel involved in nuclear criticality safety (NCS). The committee is exploring the need for developing a standard or other mechanism for establishing minimum qualifications for NCS professionals. The development of standards and regulatory guides for nuclear power plant personnel may serve as a guide in developing the minimum qualifications for NCS professionals

  5. Employment effects of minimum wages

    OpenAIRE

    Neumark, David

    2014-01-01

    The potential benefits of higher minimum wages come from the higher wages for affected workers, some of whom are in low-income families. The potential downside is that a higher minimum wage may discourage employers from using the low-wage, low-skill workers that minimum wages are intended to help. Research findings are not unanimous, but evidence from many countries suggests that minimum wages reduce the jobs available to low-skill workers.

  6. 75 FR 6151 - Minimum Capital

    Science.gov (United States)

    2010-02-08

    ... capital and reserve requirements to be issued by order or regulation with respect to a product or activity... minimum capital requirements. Section 1362(a) establishes a minimum capital level for the Enterprises... entities required under this section.\\6\\ \\3\\ The Bank Act's current minimum capital requirements apply to...

  7. 尖速比对风力发电机发电效率的影响%The influence of tip speed ratio on the wind turbine power generation efficiency

    Institute of Scientific and Technical Information of China (English)

    高峰

    2014-01-01

    This paper adopts the method of combining experimental and numerical analysis, conducts the research in view of tip speed ratio influence factors of the wind generator output performance, by changing the tip speed ratio of wind turbine output power, current, voltage and the influence coefficient of utilization of wind energy analysis, found the tip speed ratio of wind generator output power, current and voltage and the wind energy utilization coefficient influence, provides the reference for the design and manufacturing.%本文采用实验和数值分析相结合的方法,针对影响风力发电机输出性能的尖速比因素进行研究,通过尖速比的变化对风力发电机的输出功率、电流、电压以及风能利用系数的影响分析,找到了尖速比对风力发电机的输出功率、电流、电压以及风能利用系数影响程度,为设计或制造提供参考。

  8. Wheel speed management control system for spacecraft

    Science.gov (United States)

    Goodzeit, Neil E. (Inventor); Linder, David M. (Inventor)

    1991-01-01

    A spacecraft attitude control system uses at least four reaction wheels. In order to minimize reaction wheel speed and therefore power, a wheel speed management system is provided. The management system monitors the wheel speeds and generates a wheel speed error vector. The error vector is integrated, and the error vector and its integral are combined to form a correction vector. The correction vector is summed with the attitude control torque command signals for driving the reaction wheels.

  9. Speed scaling for weighted flow time

    NARCIS (Netherlands)

    Bansal, N.; Pruhs, K.R.; Stein, C.

    2007-01-01

    In addition to the traditional goal of efficiently managing time and space, many computers now need to efficiently manage power usage. For example, Intel's SpeedStep and AMD's PowerNOW technologies allow the Windows XP operating system to dynamically change the speed of the processor to prolong

  10. Utilization technique on variable speed device

    International Nuclear Information System (INIS)

    1989-12-01

    This reports of workshop on power technology describes using technique on variable speed device, which deals with alternating current situation and prospect of current variable speed device, technical trend and prospect of electronics, reduce expenses by variable speed device, control technique, measurement technology, high voltage variable speed device, recent trend of inverter technology, low voltage and high voltage variable speed device control device, operating variable speed device in cooling fan, FDF application and defect case of variable speed device, cooling pump application of water variable transformer, inverter application and energy effect of ventilation equipment, application of variable speed device and analysis of the result of operation and study for application of variable speed technology.

  11. Power

    DEFF Research Database (Denmark)

    Elmholdt, Claus Westergård; Fogsgaard, Morten

    2016-01-01

    and creativity suggests that when managers give people the opportunity to gain power and explicate that there is reason to be more creative, people will show a boost in creative behaviour. Moreover, this process works best in unstable power hierarchies, which implies that power is treated as a negotiable....... It is thus a central point that power is not necessarily something that breaks down and represses. On the contrary, an explicit focus on the dynamics of power in relation to creativity can be productive for the organisation. Our main focus is to elaborate the implications of this for practice and theory...

  12. Allocation of optimal distributed generation using GA for minimum ...

    African Journals Online (AJOL)

    user

    quality of supply and reliability in tern extending equipment maintenance intervals and ... The performance of the method is tested on 33-bus test system and ... minimum real power losses of the system by calculating DG size at different buses.

  13. Heart rate-based lactate minimum test: a reproducible method.

    NARCIS (Netherlands)

    Strupler, M.; Muller, G.; Perret, C.

    2009-01-01

    OBJECTIVE: To find the individual intensity for aerobic endurance training, the lactate minimum test (LMT) seems to be a promising method. LMTs described in the literature consist of speed or work rate-based protocols, but for training prescription in daily practice mostly heart rate is used. The

  14. Temperature dependence of the minimum in AC power losses of (Nb/sub 0.99/Zr/sub 0.01/)3Sn in parallel AC and DC magnetic fields

    International Nuclear Information System (INIS)

    Kovachev, V.T.

    1980-01-01

    ac losses P/sub L/ of bronze-processed (Nb/sub 0.99/Zr/sub 0.01/) 3 Sn strips have been measured between 4.2 and 16.5 K in the presence of a dc magnetic field H 0 . The measurements were performed using an electronic wattmeter with both ac and dc fields parallel to the long flat surfaces of the sample. A minimum in the function P/sub L/(H 0 ) was observed for fixed ac amplitudes h 0 . This minimum was found to occur in the entire temperature range between 4.2 and 16.5 K. A similar minimum was recently reported in Nb 3 Ge [Thompson et al., J. Appl. Phys. 50, 3514 (1979)] at 4.2 K. The position of the minimum is explained here by the same physical model as in Thompson et al. [J. Appl. Phys. 50, 3514 (1979)]; and Clem (ibid. 3518), but extending the model to include the temperature dependence of the entry surface shielding fields ΔH/sub en/(B,T) for flux density in the sample B=0. It is also shown here that loss minimum measurements can be used for the determination of ΔH/sub en/(0,T) in the temperature range 4.2--16.5 K

  15. Self-Powered, High-Speed and Visible-Near Infrared Response of MoO(3-x)/n-Si Heterojunction Photodetector with Enhanced Performance by Interfacial Engineering.

    Science.gov (United States)

    Zhao, Chuanxi; Liang, Zhimin; Su, Mingze; Liu, Pengyi; Mai, Wenjie; Xie, Weiguang

    2015-11-25

    Photodetectors with a wide spectrum response are important components for sensing, imaging, and other optoelectronic applications. A molybdenum oxide (MoO(3-x))/Si heterojunction has been applied as solar cells with great success, but its potential in photodetectors has not been explored yet. Herein, a self-powered, high-speed heterojunction photodetector fabricated by coating an n-type Si hierarchical structure with an ultrathin hole-selective layer of molybdenum oxide (MoO(3-x)) is first investigated. Excellent and stable photoresponse performance is obtained by using a methyl group passivated interface. The heterojunction photodetector demonstrated high sensitivity to a wide spectrum from 300 to 1100 nm. The self-powered photodetector shows a high detectivity of (∼6.29 × 10(12) cmHz(1/2) W(-1)) and fast response time (1.0 μs). The excellent photodetecting performance is attributed to the enhanced interfacial barrier height and three-dimensional geometry of Si nanostructures, which is beneficial for efficient photocarrier collection and transportation. Finally, our devices show excellent long-term stability in air for 6 months with negligible performance degradation. The thermal evaporation method for large-scale fabrication of MoO(3-x)/n-Si photodetectors makes it suitable for self-powered, multispectral, and high-speed response photodetecting applications.

  16. Analysis on Designed Wind Speed of Wind Power Generator Based on Wind Source Estimation%基于风资源评估的风电机组设计风速分析

    Institute of Scientific and Technical Information of China (English)

    华荣芹; 张新燕; 胡立锦

    2014-01-01

    Taking topography and wind source of one wind area in Xinjiang as study object,this paper analyzes basic data of the historic wind source.By calculating and analyzing main parameters such as wind energy density,wind direction frequen-cy,direction distribution of wind energy density,yearly change of wind speed,turbulence intensity and yearly generating ca-pacity,it optimizes and ensures designed wind speed and power of the wind power generator in favor of this area.By exem-plification,it analyzes impact of wake flow and points out problems to be noted for model selection and configuration for the wind power generator.%以新疆某风区的地形、风资源情况为研究对象,分析其历史风资源基础数据。通过计算、分析风能密度、风向频率及风能密度的方向分布、风速年变化、湍流强度、年发电量等主要参数,优化和确定有利于该地区的风力机设计风速和功率。通过例证分析了尾流的影响,指出进行风力发电机组选型和配置时应注意的问题。

  17. Wind-Tunnel Investigation at Low Speed of the Pitching Stability Derivatives of a 1/9-Scale Powered Model of the Convair XFY-1 Vertically Rising Airplane, TED No. NACA DE 373

    Science.gov (United States)

    Queijo, M. J.; Wolhart, Walter D.; Fletcher, H. S.

    1953-01-01

    An experimental investigation has been conducted in the Langley stability tunnel at low speed to determine the pitching stability derivatives of a 1/9-scale powered model of the Convair XFY-1 vertically rising airplane. Effects of thrust coefficient, control deflections, and propeller blade angle were investigated. The tests were made through an angle-of-attack range from about -4deg to 29deg, and the thrust coefficient range was from 0 to 0.7. In order to expedite distribution of these data, no analysis of the data has been prepared for this paper.

  18. High speed reaction wheels for satellite attitude control and energy storage

    Science.gov (United States)

    Studer, P.; Rodriguez, E.

    1985-01-01

    The combination of spacecraft attitude control and energy storage (ACES) functions in common hardware, to synergistically maintain three-axis attitude control while supplying electrical power during earth orbital eclipses, allows the generation of control torques by high rotating speed wheels that react against the spacecraft structure via a high efficiency bidirectional energy conversion motor/generator. An ACES system encompasses a minimum of four wheels, controlling power and the three torque vectors. Attention is given to the realization of such a system with composite flywheel rotors that yield high energy density, magnetic suspension technology yielding low losses at high rotational speeds, and an ironless armature permanent magnet motor/generator yielding high energy conversion efficiency.

  19. Combination of Markov chain and optimal control solved by Pontryagin’s Minimum Principle for a fuel cell/supercapacitor vehicle

    International Nuclear Information System (INIS)

    Hemi, Hanane; Ghouili, Jamel; Cheriti, Ahmed

    2015-01-01

    Highlights: • A combination of Markov chain and an optimal control solved by Pontryagin’s Minimum Principle is presented. • This strategy is applied to hybrid electric vehicle dynamic model. • The hydrogen consumption is analyzed for two different vehicle mass and drive cycle. • The supercapacitor and fuel cell behavior is analyzed at high or sudden required power. - Abstract: In this article, a real time optimal control strategy based on Pontryagin’s Minimum Principle (PMP) combined with the Markov chain approach is used for a fuel cell/supercapacitor electrical vehicle. In real time, at high power and at high speed, two phenomena are observed. The first is obtained at higher required power, and the second is observed at sudden power demand. To avoid these situations, the Markov chain model is proposed to predict the future power demand during a driving cycle. The optimal control problem is formulated as an equivalent consumption minimization strategy (ECMS), that has to be solved by using the Pontryagin’s Minimum Principle. A Markov chain model is added as a separate block for a prediction of required power. This approach and the whole system are modeled and implemented using the MATLAB/Simulink. The model without Markov chain block and the model is with it are compared. The results presented demonstrate the importance of a Markov chain block added to a model

  20. Application of Beyond Bound Decoding for High Speed Optical Communications

    DEFF Research Database (Denmark)

    Li, Bomin; Larsen, Knud J.; Vegas Olmos, Juan José

    2013-01-01

    This paper studies the application of beyond bound decoding method for high speed optical communications. This hard-decision decoding method outperforms traditional minimum distance decoding method, with a total net coding gain of 10.36 dB.......This paper studies the application of beyond bound decoding method for high speed optical communications. This hard-decision decoding method outperforms traditional minimum distance decoding method, with a total net coding gain of 10.36 dB....

  1. Disc-shaped LIM for levitation and traction force control powered by the source using the component synchronous with the motor speed

    Directory of Open Access Journals (Sweden)

    Morizane Toshimitsu

    2015-12-01

    Full Text Available It has been proposed that a novel maglev transport system uses both of the attractive force and thrust force of the Linear Induction Motor (LIM. In our proposal, these two forces will be controlled by two different frequency components. One of the frequency components is synchronous with the motor speed (fm. Another frequency component is drive frequency (fd. Our proposed system enables the independent and simultaneous control of the attractive and thrust force of LIM. Each value of the attractive and the thrust force generated by fm and fd must be identified in order to design that LIM control system. For these purpose, a disc-shaped LIM has been developed as an experimental equipment. The force profiles, especially around zero slip, have been analyzed under experimental conditions.

  2. Innovation in Vertical Axis Hydrokinetic Turbine – Straight Blade Cascaded (VAHT-SBC) design and testing for low current speed power generation

    Science.gov (United States)

    Hantoro, R.; Utama, I. K. A. P.; Arief, I. S.; Ismail, A.; Manggala, S. W.

    2018-05-01

    This study examines an innovative turbine with the addition of the number and arrangement of straight blade cascaded (SBC). SBC is a combination of passive variable-pitch and fixed pitch of each turbine arm. This study was conducted in an open channel flow that has a current velocity (V-m/s) of 1.1, 1.2, and 1.3. RPM and torque ware measured for coefficient of performance (Cp) and tip speed ratio (TSR) calculation. Without changing the turbine dimension, the employment of cascaded blade (three blades in each arm) contributes to improve energy extraction significantly. A significant increase in Cp value is seen when 9 blades (3 cascaded blades per arm) are used with a Cp 0.42 value at TSR 2.19. This value has reached 93% of the maximum theoritical Cp value.

  3. Rolling scheduling of electric power system with wind power based on improved NNIA algorithm

    Science.gov (United States)

    Xu, Q. S.; Luo, C. J.; Yang, D. J.; Fan, Y. H.; Sang, Z. X.; Lei, H.

    2017-11-01

    This paper puts forth a rolling modification strategy for day-ahead scheduling of electric power system with wind power, which takes the operation cost increment of unit and curtailed wind power of power grid as double modification functions. Additionally, an improved Nondominated Neighbor Immune Algorithm (NNIA) is proposed for solution. The proposed rolling scheduling model has further improved the operation cost of system in the intra-day generation process, enhanced the system’s accommodation capacity of wind power, and modified the key transmission section power flow in a rolling manner to satisfy the security constraint of power grid. The improved NNIA algorithm has defined an antibody preference relation model based on equal incremental rate, regulation deviation constraints and maximum & minimum technical outputs of units. The model can noticeably guide the direction of antibody evolution, and significantly speed up the process of algorithm convergence to final solution, and enhance the local search capability.

  4. Speeds in school zones.

    Science.gov (United States)

    2009-02-01

    School speed zones are frequently requested traffic controls for school areas, based on the common belief : that if the transportation agency would only install a reduced speed limit, then drivers would no longer : speed through the area. This resear...

  5. Time optimal paths for high speed maneuvering

    Energy Technology Data Exchange (ETDEWEB)

    Reister, D.B.; Lenhart, S.M.

    1993-01-01

    Recent theoretical results have completely solved the problem of determining the minimum length path for a vehicle with a minimum turning radius moving from an initial configuration to a final configuration. Time optimal paths for a constant speed vehicle are a subset of the minimum length paths. This paper uses the Pontryagin maximum principle to find time optimal paths for a constant speed vehicle. The time optimal paths consist of sequences of axes of circles and straight lines. The maximum principle introduces concepts (dual variables, bang-bang solutions, singular solutions, and transversality conditions) that provide important insight into the nature of the time optimal paths. We explore the properties of the optimal paths and present some experimental results for a mobile robot following an optimal path.

  6. Radiation-hard mid-power booster optical fiber amplifiers for high-speed digital and analogue satellite laser communication links

    Science.gov (United States)

    Stampoulidis, L.; Kehayas, E.; Stevens, G.; Henwood-Moroney, L.; Hosking, P.; Robertson, A.

    2017-11-01

    Optical laser communications (OLC) has been identified as the technology to enable high-data rate, secure links between and within satellites, as well as between satellites and ground stations with decreased mass, size, and electrical power compared to traditional RF technology.

  7. Planetary tides during the Maunder sunspot minimum

    International Nuclear Information System (INIS)

    Smythe, C.M.; Eddy, J.A.

    1977-01-01

    Sun-centered planetary conjunctions and tidal potentials are here constructed for the AD1645 to 1715 period of sunspot absence, referred to as the 'Maunder Minimum'. These are found to be effectively indistinguishable from patterns of conjunctions and power spectra of tidal potential in the present era of a well established 11 year sunspot cycle. This places a new and difficult restraint on any tidal theory of sunspot formation. Problems arise in any direct gravitational theory due to the apparently insufficient forces and tidal heights involved. Proponents of the tidal hypothesis usually revert to trigger mechanisms, which are difficult to criticise or test by observation. Any tidal theory rests on the evidence of continued sunspot periodicity and the substantiation of a prolonged period of solar anomaly in the historical past. The 'Maunder Minimum' was the most drastic change in the behaviour of solar activity in the last 300 years; sunspots virtually disappeared for a 70 year period and the 11 year cycle was probably absent. During that time, however, the nine planets were all in their orbits, and planetary conjunctions and tidal potentials were indistinguishable from those of the present era, in which the 11 year cycle is well established. This provides good evidence against the tidal theory. The pattern of planetary tidal forces during the Maunder Minimum was reconstructed to investigate the possibility that the multiple planet forces somehow fortuitously cancelled at the time, that is that the positions of the slower moving planets in the 17th and early 18th centuries were such that conjunctions and tidal potentials were at the time reduced in number and force. There was no striking dissimilarity between the time of the Maunder Minimum and any period investigated. The failure of planetary conjunction patterns to reflect the drastic drop in sunspots during the Maunder Minimum casts doubt on the tidal theory of solar activity, but a more quantitative test

  8. Calculation of Wind Speeds for Return Period Using Weibull Parameter: A Case Study of Hanbit NPP Area

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jongk Uk; Lee, Kwan Hee; Kim, Sung Il; Yook, Dae Sik; Ahn, Sang Myeon [KINS, Daejeon (Korea, Republic of)

    2016-05-15

    Evaluation of the meteorological characteristics at the nuclear power plant and in the surrounding area should be performed in determining the site suitability for safe operation of the nuclear power plant. Under unexpected emergency condition, knowledge of meteorological information on the site area is important to provide the basis for estimating environmental impacts resulting from radioactive materials released in gaseous effluents during the accident condition. In the meteorological information, wind speed and direction are the important meteorological factors for examination of the safety analysis in the nuclear power plant area. Wind characteristics was analyzed on Hanbit NPP area. It was found that the Weibull parameters k and c vary 2.56 to 4.77 and 4.53 to 6.79 for directional wind speed distribution, respectively. Maximum wind frequency was NE and minimum was NNW.

  9. Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

    DEFF Research Database (Denmark)

    Hu, Weihao; Zhang, Yunqian; Chen, Zhe

    2013-01-01

    operation. A new method of flicker mitigation by controlling the rotational speed is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the rotational speed of the PMSG. Simulation results show that damping the 3p active power...... oscillation by using the flicker mitigation speed controller is an effective means for flicker mitigation of variable speed wind turbines with full-scale back-to-back power converters and PMSG during continuous operation.......Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG...

  10. Caribic EEG. A new regulation speeds up the solar power market in the Dominical Republic; Karibik-EEG. Eine neue Richtlinie belebt den Solarstrommarkt in der Dominikanischen Republik

    Energy Technology Data Exchange (ETDEWEB)

    Rosell, Alejandro Diego

    2011-09-15

    In spite of its sunny weather conditions, the Dominican Republic so far has only solar systems with a total of 500 kW. But a new law came into force that permits backward current meters. Those who generate more power than they consume will even get a reimbursement. With additional tax exemptions, the payback period of solar systems will be only a few years.

  11. Wind speed prediction using statistical regression and neural network

    Indian Academy of Sciences (India)

    Prediction of wind speed in the atmospheric boundary layer is important for wind energy assess- ment,satellite launching and aviation,etc.There are a few techniques available for wind speed prediction,which require a minimum number of input parameters.Four different statistical techniques,viz.,curve fitting,Auto Regressive ...

  12. Measures for speed management.

    NARCIS (Netherlands)

    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

  13. Reducing Heating In High-Speed Cinematography

    Science.gov (United States)

    Slater, Howard A.

    1989-01-01

    Infrared-absorbing and infrared-reflecting glass filters simple and effective means for reducing rise in temperature during high-speed motion-picture photography. "Hot-mirror" and "cold-mirror" configurations, employed in projection of images, helps prevent excessive heating of scenes by powerful lamps used in high-speed photography.

  14. The Risk Management of Minimum Return Guarantees

    Directory of Open Access Journals (Sweden)

    Antje Mahayni

    2008-05-01

    Full Text Available Contracts paying a guaranteed minimum rate of return and a fraction of a positive excess rate, which is specified relative to a benchmark portfolio, are closely related to unit-linked life-insurance products and can be considered as alternatives to direct investment in the underlying benchmark. They contain an embedded power option, and the key issue is the tractable and realistic hedging of this option, in order to rigorously justify valuation by arbitrage arguments and prevent the guarantees from becoming uncontrollable liabilities to the issuer. We show how to determine the contract parameters conservatively and implement robust risk-management strategies.

  15. Energy-efficient adjustable speed double inverter-fed woundrotor ...

    African Journals Online (AJOL)

    Energy-efficient adjustable speed double inverter-fed woundrotor induction motor ... at speeds up to double rated without the magnetic flux reducing is presented. ... Keywords: power, double-fed wound-rotor induction motor drive, steel and ...

  16. A high-speed data acquisition system to measure low-level current from self-powered flux detectors in CANDU nuclear reactors

    International Nuclear Information System (INIS)

    Lawrence, C.B.; Hall, D.S.

    1982-05-01

    Self-powered flux detectors are used in CANDU nuclear power reactors to determine the spatial neutron flux distribution in the reactor core for use by both the reactor control and safety systems. To establish the dynamic response of different types of flux detectors, the Chalk River Nuclear Laboratories have an ongoing experimental irradiation program in the NRU research reactor for which a data acquistion system has been developed. The system described in this paper is used to measure the currents from the detectors both at a slow, regular logging interval, and at a rapid, adaptive rate following a reactor shutdown. Currents that range from 100 pA to 1 mA full scale can be measured from up to 38 detectors and stored at sampling rates of up to 20 samples per second. The dynamic characteristics of the detectors can be computed from the stored records. The data acquisition system comprises a DEC LSI-11/23 microcomputer, dual cartridge disks, floppy disks, a hard copy and a video display terminal. The RT-11 operating system is used and all application programs are written in FORTRAN

  17. Study of junior weight lifters’ special fitness with different methods of speed-power training in preparatory period of general preparatory stage

    Directory of Open Access Journals (Sweden)

    O. B. Piven

    2015-09-01

    Full Text Available Purpose: studying of junior weight lifters’ special fitness in preparatory period of general preparatory stage. Material: 30 junior weight lifters of 12 - 14 years’ old age were involved in experiment (2 nd and 3 rd sport grades. Results: optimal indicators of training by shock method have been determined for sportsmen of experimental group. Scope of loads was: squats with barbell on shoulders - lifting 779 times (90 tons; 310 jumps in depth and jumps out. Power indicators in total of combined exercises have increased by 16.5 kg. In control group other methodic was used. In control group scope of loads was: lifting of barbell - 910 times (111 tons. Power indicators in total of combined exercises have increased by 7.2 kg. Conclusions: the following regiment of training is recommended: first 3 weeks - jumps. Dozing and load scopes shall be as follows: first two trainings - two attempts (10 times each with height of 0.5 m; third training - 3 attempts (10 times each with height of 0.5 m; forth training - 4 attempts (10 times each with height of 0.7 m. Jumps in depth shall be used 3 times weekly.

  18. Energy and environmental norms on Minimum Vital Flux

    International Nuclear Information System (INIS)

    Maran, S.

    2008-01-01

    By the end of the year will come into force the recommendations on Minimum Vital flow and operators of hydroelectric power plants will be required to make available part of water of their derivations in order to protect river ecosystems. In this article the major energy and environmental consequences of these rules, we report some quantitative evaluations and are discusses the proposals for overcoming the weaknesses of the approach in the estimation of Minimum Vital Flux [it

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

    Science.gov (United States)

    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.

  20. Slower speed and stronger coupling: adaptive mechanisms of chaos synchronization.

    Science.gov (United States)

    Wang, Xiao Fan

    2002-06-01

    We show that two initially weakly coupled chaotic systems can achieve synchronization by adaptively reducing their speed and/or enhancing the coupling strength. Explicit adaptive algorithms for speed reduction and coupling enhancement are provided. We apply these algorithms to the synchronization of two coupled Lorenz systems. It is found that after a long-time adaptive process, the two coupled chaotic systems can achieve synchronization with almost the minimum required coupling-speed ratio.

  1. A Preliminary Analysis of the Flying Qualities of the Consolidated Vultee MX-813 Delta-Wing Airplane Configuration at Transonic and Low Supersonic Speeds as Determined from Flights of Rocket-Powered Models

    Science.gov (United States)

    Mitcham, Grady L.

    1949-01-01

    A preliminary analysis of the flying qualities of the Consolidated Vultee MX-813 delta-wing airplane configuration has been made based on the results obtained from the first two 1/8 scale models flown at the NACA Pilotless Aircraft Research Station, Wallop's Island, VA. The Mach number range covered in the tests was from 0.9 to 1.2. The analysis indicates adequate elevator control for trim in level flight over the speed range investigated. Through the transonic range there is a mild trim change with a slight tucking-under tendency. The elevator control effectiveness in the supersonic range is reduced to about one-half the subsonic value although sufficient control for maneuvering is available as indicated by the fact that 10 deg elevator deflection produced 5g acceleration at Mach number of 1.2 at 40,000 feet.The elevator control forces are high and indicate the power required of the boost system. The damping. of the short-period oscillation is adequate at sea-level but is reduced at 40,000 feet. The directional stability appears adequate for the speed range and angles of attack covered.

  2. Análisis preliminar del Límite de Potencia Eólica para grandes perturbaciones utilizando aerogeneradores de velocidad fija; Partial analysis of wind power limit for large disturbance using fixed speed wind turbine

    Directory of Open Access Journals (Sweden)

    Ariel Santos Fuentefria

    2015-04-01

    Full Text Available El Límite de Potencia Eólica (LPE es la cantidad de potencia eólica que permite un sistema sin perder la estabilidad y depende principalmente de las características de los generadores eólicos y de las características del sistema en términos de debilidad. Conocer el comportamiento del sistema en régimen transitorio es sumamente importante; entre las condiciones que generan mayores problemas se encuentran el cortocircuito en las líneas de mayor transferencia de potenciay la salida de algún generador del sistema. El LPE cambia para cada condición y conocer el LPE considerando estas condiciones permite aprovechar al máximo la energía del viento. En el presente trabajo se analiza el comportamiento de generadores eólicos de velocidad fija para diversas condiciones transitorias de la red, utilizándose el sistema de prueba de 14 nodos de la IEEE para verificar la metodología en uso para el análisis a través de simulaciones implementadas en el software libre PSAT.  The amount of wind power that allow an electric network without losing his stability as known as wind power limit. The wind power limit fundamentally depends on the wind turbine technology and the weakness level of the system. To know the system behaviors in dynamic performance having into account the worst disturbance is a very important matter, a short circuit in one of the most power transference line or the loss of a large generation unit was a large disturbance that can affect system stability. The wind power limit may change with the nature of the disturbance. To know the wind power limit considering this conditions allow use the wind at maximum level. In the present paper the behavior of fixed speed wind turbine for different fault types is analyzed, at those conditions, the wind power is increasing until the system become voltage unstable. For the analysis the IEEE 14 Bus Test Case is used. The Power System Analysis Toolbox (PSAT package is used for the simulation.

  3. Análisis preliminar del Límite de Potencia Eólica para grandes perturbaciones utilizando aerogeneradores de velocidad fija; Partial analysis of wind power limit for large disturbance using fixed speed wind turbine

    Directory of Open Access Journals (Sweden)

    Ariel Santos Fuentefria

    2014-06-01

    Full Text Available El Límite de Potencia Eólica (LPE es la cantidad de potencia eólica que permite un sistema sin perder la estabilidad y depende principalmente de las características de los generadores eólicos y de las características del sistema en términos de debilidad. Conocer el comportamiento del sistema en régimen transitorio es sumamente importante; entre las condiciones que generan mayores problemas se encuentran el cortocircuito en las líneas de mayor transferencia de potenciay la salida de algún generador del sistema. El LPE cambia para cada condición y conocer el LPE considerando estas condiciones permite aprovechar al máximo la energía del viento. En el presente trabajo se analiza el comportamiento de generadores eólicos de velocidad fija para diversas condiciones transitorias de la red, utilizándose el sistema de prueba de 14 nodos de la IEEE para verificar la metodología en uso para el análisis a través de simulaciones implementadas en el software libre PSAT The amount of wind power that allow an electric network without losing his stability as known as wind power limit. The wind power limit fundamentally depends on the wind turbine technology and the weakness level of the system. To know the system behaviors in dynamic performance having into account the worst disturbance is a very important matter, a short circuit in one of the most power transference line or the loss of a large generation unit was a large disturbance that can affect system stability. The wind power limit may change with the nature of the disturbance. To know the wind power limit considering this conditions allow use the wind at maximum level. In the present paper the behavior of fixed speed wind turbine for different fault types is analyzed, at those conditions, the wind power is increasing until the system become voltage unstable. For the analysis the IEEE 14 Bus Test Case is used. The Power System Analysis Toolbox (PSAT package is used for the simulation.

  4. Design for minimum energy in interstellar communication

    Science.gov (United States)

    Messerschmitt, David G.

    2015-02-01

    Microwave digital communication at interstellar distances is the foundation of extraterrestrial civilization (SETI and METI) communication of information-bearing signals. Large distances demand large transmitted power and/or large antennas, while the propagation is transparent over a wide bandwidth. Recognizing a fundamental tradeoff, reduced energy delivered to the receiver at the expense of wide bandwidth (the opposite of terrestrial objectives) is advantageous. Wide bandwidth also results in simpler design and implementation, allowing circumvention of dispersion and scattering arising in the interstellar medium and motion effects and obviating any related processing. The minimum energy delivered to the receiver per bit of information is determined by cosmic microwave background alone. By mapping a single bit onto a carrier burst, the Morse code invented for the telegraph in 1836 comes closer to this minimum energy than approaches used in modern terrestrial radio. Rather than the terrestrial approach of adding phases and amplitudes increases information capacity while minimizing bandwidth, adding multiple time-frequency locations for carrier bursts increases capacity while minimizing energy per information bit. The resulting location code is simple and yet can approach the minimum energy as bandwidth is expanded. It is consistent with easy discovery, since carrier bursts are energetic and straightforward modifications to post-detection pattern recognition can identify burst patterns. Time and frequency coherence constraints leading to simple signal discovery are addressed, and observations of the interstellar medium by transmitter and receiver constrain the burst parameters and limit the search scope.

  5. Wind-Tunnel Investigation at Low Speed of the Yawing Stability Derivatives of a 1/9-Scale Powered Model of the Convair XFY-1 Vertically Rising Airplane, TED No. NACA DE 373

    Science.gov (United States)

    Queijo, M. J.; Wolhart, w. D.; Fletcher, H. S.

    1953-01-01

    An experimental investigation has been conducted in the Langley stability tunnel at low speed to deter+nine the yawing stability derivatives of a 1/9-scale powered model of the Convair XFY-1 vertically rising airplane. Effects of thrust coefficient were investigated for the complete model and for certain components of the model. Effects of control deflections and of propeller blade angle were investigated for the complete model. Most of the tests were made through an angle-of-attack range from about -4deg to 29deg, and the thrust coefficient range was from 0 to 0.7. In order to expedite distribution of these data, no analysis of the data has been prepared for this.

  6. Wind-Tunnel Investigation at Low Speed of the Rolling Stability Derivatives of a 1/9-Scale Powered Model of the Convair XFY-1 Vertically Rising Airplane, TED No. NACA DE 373

    Science.gov (United States)

    Queijo, M. J.; Wolhart, Walter D.; Fletcher, H. S.

    1953-01-01

    An experimental investigation has been conducted in the Langley stability tunnel at low speed to determine the rolling stability derivatives of a 1/9-scale powered model of the Convair XFY-1 vertically rising airplane. Effects of thrust coefficient were investigated for the complete model and for certain components of the model. Effects of control deflections and of propeller blade angle were investigated for the complete model. Most of the tests were made through an angle-of-attack range from about -4deg to 29deg, and the thrust coefficient range was from 0 to 0.7. In order to expedite distribution of these data, no analysis of the data has been prepared for this paper.

  7. Physical demands on young elite European female basketball players with special reference to speed, agility, explosive strength, and take-off power.

    Science.gov (United States)

    Erčulj, Frane; Blas, Mateja; Bračič, Mitja

    2010-11-01

    The aim of the study was to determine and analyze the level of certain motor abilities (acceleration and agility, the explosive strength of arms, and take-off power) of young elite European female basketball players. We also wanted to establish whether there were any differences between 3 groups of female basketball players who differed in terms of their playing performance. The sample of subjects consists of 65 female basketball players aged 14.49 (± 0.61) years who were divided into 3 groups (divisions A, B, and C of the European Championships). We compare the groups by using 8 motor tests. p Values training status, this is also 1 of the key reasons for these players' lower playing efficiency compared to those from divisions A and B. We hope the findings of this study will enable the generation of model values, which can assist basketball coaches for this age category in basketball clubs, high schools, national teams, and basketball camps.

  8. Multi-objective optimization of MOSFETs channel widths and supply voltage in the proposed dual edge-triggered static D flip-flop with minimum average power and delay by using fuzzy non-dominated sorting genetic algorithm-II.

    Science.gov (United States)

    Keivanian, Farshid; Mehrshad, Nasser; Bijari, Abolfazl

    2016-01-01

    D Flip-Flop as a digital circuit can be used as a timing element in many sophisticated circuits. Therefore the optimum performance with the lowest power consumption and acceptable delay time will be critical issue in electronics circuits. The newly proposed Dual-Edge Triggered Static D Flip-Flop circuit layout is defined as a multi-objective optimization problem. For this, an optimum fuzzy inference system with fuzzy rules is proposed to enhance the performance and convergence of non-dominated sorting Genetic Algorithm-II by adaptive control of the exploration and exploitation parameters. By using proposed Fuzzy NSGA-II algorithm, the more optimum values for MOSFET channel widths and power supply are discovered in search space than ordinary NSGA types. What is more, the design parameters involving NMOS and PMOS channel widths and power supply voltage and the performance parameters including average power consumption and propagation delay time are linked. To do this, the required mathematical backgrounds are presented in this study. The optimum values for the design parameters of MOSFETs channel widths and power supply are discovered. Based on them the power delay product quantity (PDP) is 6.32 PJ at 125 MHz Clock Frequency, L = 0.18 µm, and T = 27 °C.

  9. Dynamic Shift Coordinated Control Based on Motor Active Speed Synchronization with the New Hybrid System

    Directory of Open Access Journals (Sweden)

    Ting Yan

    2017-01-01

    Full Text Available Considering the inherent disadvantages that severely affect driving comfortability during the shift process in HEVs, a dynamic shift coordinated control based on motor active speed synchronization is proposed to improve shift quality by reduction of shift vibration. The whole control scheme is comprised of three phases, preparatory phase, speed regulation phase, and synchronization phase, which are implemented consecutively in order. The key to inhibiting impact and jerk depends on the speed regulation phase, where motor active speed synchronization is utilized to reach the minimum speed difference between the two ends of synchronizer. A new hybrid system with superior performances is applied to present the validity of the adopted control algorithm during upshift or downshift, which can represent planetary gear system and conventional AMT shift procedure, respectively. Bench test, simulation, and road test results show that, compared with other methods, the proposed dynamic coordinated control can achieve shifting control in real time to effectively improve gear-shift comfort and shorten power interruption transients, with robustness in both conventional AMT and planetary gear train.

  10. Minimum Q Electrically Small Antennas

    DEFF Research Database (Denmark)

    Kim, O. S.

    2012-01-01

    Theoretically, the minimum radiation quality factor Q of an isolated resonance can be achieved in a spherical electrically small antenna by combining TM1m and TE1m spherical modes, provided that the stored energy in the antenna spherical volume is totally suppressed. Using closed-form expressions...... for a multiarm spherical helix antenna confirm the theoretical predictions. For example, a 4-arm spherical helix antenna with a magnetic-coated perfectly electrically conducting core (ka=0.254) exhibits the Q of 0.66 times the Chu lower bound, or 1.25 times the minimum Q....

  11. Investigation on amorphous InGaZnO based resistive switching memory with low-power, high-speed, high reliability

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yang-Shun [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan, ROC (China); Liu, Po-Tsun, E-mail: ptliu@mail.nctu.edu.tw [Department of Photonics and Display Institute, National Chiao Tung University, Hsinchu 30010, Taiwan, ROC (China); Hsu, Ching-Hui [Department of Photonics and Display Institute, National Chiao Tung University, Hsinchu 30010, Taiwan, ROC (China)

    2013-12-31

    Recently, non-volatile memory (NVM) has been widely used in electronic devices. Nowadays, the prevailing NVM is Flash memory. However, it is generally believed that the conventional Flash memory will approach its scaling limit within about a decade. The resistive random access memory (RRAM) is emerging as one of the potential candidates for future memory replacement because of its high storage density, low power consumption as well as simple structure. The purpose of this work is to develop a reliable a-InGaZnO based resistive switching memory. We investigate the resistive switching characteristics of TiN/Ti/IGZO/Pt structure and TiN/IGZO/Pt structure. The device with TiN/Ti/IGZO/Pt structure exhibits stable bipolar resistive switching. The impact of inserting a Ti interlayer is studied by material analyses. The device shows excellent resistive switching properties. For example, the DC sweep endurance can achieve over 1000 times; and the pulse induced switching cycles can reach at least 10,000 times. Furthermore, the impact of different sputtering ambience, the variable temperature measurement, and the conduction mechanisms are also investigated. According to our experiments, we propose a model to explain the resistive switching phenomenon observed in our devices.

  12. Numerical Evaluation ofThe Performance ofA Compression Ignition Cng Engine For Heavy DutyTrucksWithAn Optimum Speed PowerTurbine

    Directory of Open Access Journals (Sweden)

    Alberto A. Boretti

    2011-10-01

    Full Text Available The turbocharged direct injection lean burn Diesel engine is the most efficient engine now in production for transport applications. CNG is an alternative fuel with a better carbon to hydrogen ratio therefore permitting reduced carbon dioxide emissions. It is injected in gaseous form for a much cleaner combustion almost cancelling some of the emissions of the Diesel and it permits a much better energy security within Australia. The paper discusses the best options currently available to convert Diesel engine platforms to CNG, with particular emphasis to the use of these CNG engines within Australia where the refuelling network is scarce. This option is determined in the dual fuel operation with a double injector design that couples a second CNG injector to the Diesel injector. This configuration permits the operation Diesel only or Diesel pilot and CNG main depending on the availability of refuelling stations where the vehicle operates. Results of engine performance simulations are performed for a straight six cylinder 13 litres truck engine with a novel power turbine connected to the crankshaft through a constant variable transmission that may be by-passed when non helpful to increase the fuel economy of the vehicle or when damaging the performances of the after treatment system.

  13. Energy-efficient two-hop LTE resource allocation in high speed trains with moving relays

    KAUST Repository

    Alsharoa, Ahmad M.

    2014-05-01

    High-speed railway system equipped with moving relay stations placed on the middle of the ceiling of each train wagon is investigated. The users inside the train are served in two hops via the 3GPP Long Term Evolution (LTE) technology. The objective of this work is to maximize the number of served users by respecting a specific quality-of-service constraint while minimizing the total power consumption of the eNodeB and the moving relays. We propose an efficient algorithm based on the Hungarian method to find the optimal resource allocation over the LTE resource blocks in order to serve the maximum number of users with the minimum power consumption. Moreover, we derive a closed-form expression for the power allocation problem. Our simulation results illustrate the performance of the proposed scheme and compare it with various previously developed algorithms as well as with the direct transmission scenario. © 2014 IFIP.

  14. Power converter with maximum power point tracking MPPT for small wind-electric pumping systems

    International Nuclear Information System (INIS)

    Lara, David; Merino, Gabriel; Salazar, Lautaro

    2015-01-01

    Highlights: • We implement a wind electric pumping system of small power. • The power converter allowed to change the operating point of the electro pump. • Two control techniques were implemented in the power converter. • The control V/f variable allowed to increase the power generated by the permanent magnet generator. - Abstract: In this work, an AC–DC–AC direct-drive power converter was implemented for a wind electric pumping system consisting of a permanent magnet generator (PMG) of 1.3 kW and a peripheral single phase pump of 0.74 kW. In addition, the inverter linear V/f control scheme and the maximum power point tracking (MPPT) algorithm with variable V/f were developed. MPPT algorithm seeks to extract water in a wide range of power input using the maximum amount of wind power available. Experimental trials at different pump pressures were conducted. With a MPPT tracking system with variable V/f, a power value of 1.3 kW was obtained at a speed of 350 rpm and a maximum operating hydraulic head of 50 m. At lower operating heads pressures (between 10 and 40 m), variable V/f control increases the power generated by the PMG compared to the linear V/f control. This increase ranged between 4% and 23% depending on the operating pressure, with an average of 13%, getting close to the maximum electrical power curve of the PMG. The pump was driven at variable frequency reaching a minimum speed of 0.5 times the rated speed. Efficiency of the power converter ranges between 70% and 95% with a power factor between 0.4 and 0.85, depending on the operating pressure

  15. Fermat and the Minimum Principle

    Indian Academy of Sciences (India)

    Arguably, least action and minimum principles were offered or applied much earlier. This (or these) principle(s) is/are among the fundamental, basic, unifying or organizing ones used to describe a variety of natural phenomena. It considers the amount of energy expended in performing a given action to be the least required ...

  16. Torque- and Speed Control of a Pitch Regulated Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Rasila, Mika

    2003-07-01

    Variable speed operated wind turbines has the potential to reduce fatigue loads, compared to fixed speed wind turbines. With pitch controllable rotor blades limitation of the power at high wind speeds is obtained. The thesis describes different controlling aspects concerning wind turbines and how these together can be used to optimize the system's performance. Torque control is used in order to achieve reduction on the mechanical loads on the drive-train for low wind speeds and limitation of power output for high wind speeds. In the high wind speed interval torque control is effective in order to limit the output power if a sufficiently fast pitch actuator is used. In the middle wind speed interval filter utilization can be used to give a reference signal to the controller in order to reduce speed and torque variations.

  17. Speed management program plan.

    Science.gov (United States)

    2014-05-01

    Changing public attitudes regarding speeding and speed management will require a comprehensive and concerted effort, involving a wide variety of strategies. This plan identifies six primary focus areas: : A. Data and Data-Driven Approaches, : B. Rese...

  18. Small portable speed calculator

    Science.gov (United States)

    Burch, J. L.; Billions, J. C.

    1973-01-01

    Calculator is adapted stopwatch calibrated for fast accurate measurement of speeds. Single assembled unit is rugged, self-contained, and relatively inexpensive to manufacture. Potential market includes automobile-speed enforcement, railroads, and field-test facilities.

  19. Electric vehicle speed control

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, W.R.; Mc Auliffe, G.N.; Schlageter, G.A.

    1987-06-23

    This patent describes an electric vehicle driven by a DC motor. The vehicle has a field winding, an electric resistance element in circuit with the field winding, a switch in the circuit operative when closed to place. The element in parallel with the field winding weakens the field and increases potential motor speed. Also are relay means for operating the switch, means to determine motor speed, computer means for determining whether the motor speed is increasing or decreasing, and means for operating the relay means to close the switch at a first speed. If the motor speed is increased, it actuates the switch at a second speed lower than the first speed but only if switch has been closed previously and motor speed is decreasing.

  20. Parameterization of ion channeling half-angles and minimum yields

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, Barney L.

    2016-03-15

    A MS Excel program has been written that calculates ion channeling half-angles and minimum yields in cubic bcc, fcc and diamond lattice crystals. All of the tables and graphs in the three Ion Beam Analysis Handbooks that previously had to be manually looked up and read from were programed into Excel in handy lookup tables, or parameterized, for the case of the graphs, using rather simple exponential functions with different power functions of the arguments. The program then offers an extremely convenient way to calculate axial and planar half-angles, minimum yields, effects on half-angles and minimum yields of amorphous overlayers. The program can calculate these half-angles and minimum yields for 〈u v w〉 axes and [h k l] planes up to (5 5 5). The program is open source and available at (http://www.sandia.gov/pcnsc/departments/iba/ibatable.html).

  1. Quantum mechanics the theoretical minimum

    CERN Document Server

    Susskind, Leonard

    2014-01-01

    From the bestselling author of The Theoretical Minimum, an accessible introduction to the math and science of quantum mechanicsQuantum Mechanics is a (second) book for anyone who wants to learn how to think like a physicist. In this follow-up to the bestselling The Theoretical Minimum, physicist Leonard Susskind and data engineer Art Friedman offer a first course in the theory and associated mathematics of the strange world of quantum mechanics. Quantum Mechanics presents Susskind and Friedman’s crystal-clear explanations of the principles of quantum states, uncertainty and time dependence, entanglement, and particle and wave states, among other topics. An accessible but rigorous introduction to a famously difficult topic, Quantum Mechanics provides a tool kit for amateur scientists to learn physics at their own pace.

  2. Speed in Acquisitions

    DEFF Research Database (Denmark)

    Meglio, Olimpia; King, David R.; Risberg, Annette

    2017-01-01

    The advantage of speed is often invoked by academics and practitioners as an essential condition during post-acquisition integration, frequently without consideration of the impact earlier decisions have on acquisition speed. In this article, we examine the role speed plays in acquisitions across...... the acquisition process using research organized around characteristics that display complexity with respect to acquisition speed. We incorporate existing research with a process perspective of acquisitions in order to present trade-offs, and consider the influence of both stakeholders and the pre......-deal-completion context on acquisition speed, as well as the organization’s capabilities to facilitating that speed. Observed trade-offs suggest both that acquisition speed often requires longer planning time before an acquisition and that associated decisions require managerial judgement. A framework for improving...

  3. Understanding the Minimum Wage: Issues and Answers.

    Science.gov (United States)

    Employment Policies Inst. Foundation, Washington, DC.

    This booklet, which is designed to clarify facts regarding the minimum wage's impact on marketplace economics, contains a total of 31 questions and answers pertaining to the following topics: relationship between minimum wages and poverty; impacts of changes in the minimum wage on welfare reform; and possible effects of changes in the minimum wage…

  4. 5 CFR 551.301 - Minimum wage.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Minimum wage. 551.301 Section 551.301... FAIR LABOR STANDARDS ACT Minimum Wage Provisions Basic Provision § 551.301 Minimum wage. (a)(1) Except... employees wages at rates not less than the minimum wage specified in section 6(a)(1) of the Act for all...

  5. Changes in speed distribution: Applying aggregated safety effect models to individual vehicle speeds.

    Science.gov (United States)

    Vadeby, Anna; Forsman, Åsa

    2017-06-01

    This study investigated the effect of applying two aggregated models (the Power model and the Exponential model) to individual vehicle speeds instead of mean speeds. This is of particular interest when the measure introduced affects different parts of the speed distribution differently. The aim was to examine how the estimated overall risk was affected when assuming the models are valid on an individual vehicle level. Speed data from two applications of speed measurements were used in the study: an evaluation of movable speed cameras and a national evaluation of new speed limits in Sweden. The results showed that when applied on individual vehicle speed level compared with aggregated level, there was essentially no difference between these for the Power model in the case of injury accidents. However, for fatalities the difference was greater, especially for roads with new cameras where those driving fastest reduced their speed the most. For the case with new speed limits, the individual approach estimated a somewhat smaller effect, reflecting that changes in the 15th percentile (P15) were somewhat larger than changes in P85 in this case. For the Exponential model there was also a clear, although small, difference between applying the model to mean speed changes and individual vehicle speed changes when speed cameras were used. This applied both for injury accidents and fatalities. There were also larger effects for the Exponential model than for the Power model, especially for injury accidents. In conclusion, applying the Power or Exponential model to individual vehicle speeds is an alternative that provides reasonable results in relation to the original Power and Exponential models, but more research is needed to clarify the shape of the individual risk curve. It is not surprising that the impact on severe traffic crashes was larger in situations where those driving fastest reduced their speed the most. Further investigations on use of the Power and/or the

  6. 14 CFR 27.87 - Height-speed envelope.

    Science.gov (United States)

    2010-01-01

    ... applicable power failure condition in paragraph (b) of this section, a limiting height-speed envelope must be... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Height-speed envelope. 27.87 Section 27.87... STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Performance § 27.87 Height-speed envelope. (a) If there is any...

  7. 14 CFR 29.1517 - Limiting height-speed envelope.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limiting height-speed envelope. 29.1517... Operating Limitations § 29.1517 Limiting height-speed envelope. For Category A rotorcraft, if a range of... following power failure, the range of heights and its variation with forward speed must be established...

  8. Estimation of Rotor Effective Wind Speed: A Comparison

    DEFF Research Database (Denmark)

    Soltani, Mohsen; Knudsen, Torben; Svenstrup, Mikael

    2013-01-01

    Modern wind turbine controllers use wind speed information to improve power production and reduce loads on the turbine components. The turbine top wind speed measurement is unfortunately imprecise and not a good representative of the rotor effective wind speed. Consequently, many different model...... aero-servo-elastic turbine simulations and real turbine field experiments in different wind scenarios....

  9. Ant Colony Optimization and the Minimum Cut Problem

    DEFF Research Database (Denmark)

    Kötzing, Timo; Lehre, Per Kristian; Neumann, Frank

    2010-01-01

    Ant Colony Optimization (ACO) is a powerful metaheuristic for solving combinatorial optimization problems. With this paper we contribute to the theoretical understanding of this kind of algorithm by investigating the classical minimum cut problem. An ACO algorithm similar to the one that was prov...

  10. Wind Speed Preview Measurement and Estimation for Feedforward Control of Wind Turbines

    Science.gov (United States)

    Simley, Eric J.

    Wind turbines typically rely on feedback controllers to maximize power capture in below-rated conditions and regulate rotor speed during above-rated operation. However, measurements of the approaching wind provided by Light Detection and Ranging (lidar) can be used as part of a preview-based, or feedforward, control system in order to improve rotor speed regulation and reduce structural loads. But the effectiveness of preview-based control depends on how accurately lidar can measure the wind that will interact with the turbine. In this thesis, lidar measurement error is determined using a statistical frequency-domain wind field model including wind evolution, or the change in turbulent wind speeds between the time they are measured and when they reach the turbine. Parameters of the National Renewable Energy Laboratory (NREL) 5-MW reference turbine model are used to determine measurement error for a hub-mounted circularly-scanning lidar scenario, based on commercially-available technology, designed to estimate rotor effective uniform and shear wind speed components. By combining the wind field model, lidar model, and turbine parameters, the optimal lidar scan radius and preview distance that yield the minimum mean square measurement error, as well as the resulting minimum achievable error, are found for a variety of wind conditions. With optimized scan scenarios, it is found that relatively low measurement error can be achieved, but the attainable measurement error largely depends on the wind conditions. In addition, the impact of the induction zone, the region upstream of the turbine where the approaching wind speeds are reduced, as well as turbine yaw error on measurement quality is analyzed. In order to minimize the mean square measurement error, an optimal measurement prefilter is employed, which depends on statistics of the correlation between the preview measurements and the wind that interacts with the turbine. However, because the wind speeds encountered by

  11. Wind power prediction models

    Science.gov (United States)

    Levy, R.; Mcginness, H.

    1976-01-01

    Investigations were performed to predict the power available from the wind at the Goldstone, California, antenna site complex. The background for power prediction was derived from a statistical evaluation of available wind speed data records at this location and at nearby locations similarly situated within the Mojave desert. In addition to a model for power prediction over relatively long periods of time, an interim simulation model that produces sample wind speeds is described. The interim model furnishes uncorrelated sample speeds at hourly intervals that reproduce the statistical wind distribution at Goldstone. A stochastic simulation model to provide speed samples representative of both the statistical speed distributions and correlations is also discussed.

  12. Minimum scaling laws in tokamaks

    International Nuclear Information System (INIS)

    Zhang, Y.Z.; Mahajan, S.M.

    1986-10-01

    Scaling laws governing anomalous electron transport in tokamaks with ohmic and/or auxiliary heating are derived using renormalized Vlasov-Ampere equations for low frequency electromagnetic microturbulence. It is also shown that for pure auxiliary heating (or when auxiliary heating power far exceeds the ohmic power), the energy confinement time scales as tau/sub E/ ∼ P/sub inj//sup -1/3/, where P/sub inj/ is the injected power

  13. 双馈风电机组与高速永磁风电机组对比分析﹡%Comparison of Doubly-fed Induction Generator and High Speed Permanent Magnet Wind Power Generator

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    is paper compared two main wind turbines. One is doubly-fed induction generator, the other is high speed permanent magnet wind power generator. It calculated the efficiency and annual electric energy production in different IEC wind classes, and compared the cost based on the market value. A er analyzing the reliability, e ciency and power grid adaptability, it came to the conclusion that two types of wind turbines have di erent advantages and meet di erent requirements from customers. erefore, development of two types of wind turbines will be be er adapted to the market competition.%  本文从风电机组角度对两种主流的发电方式,即双馈式发电机组和高速永磁发电机组,进行了对比分析。计算了两种发电方式的效率及在不同风区的年发电量,根据市场价格对各部件进行成本对比。在综合考虑了可靠性、效率、电网适应性等方面后指出,两种方式各有特点,适合客户的不同需求。因此,作为风电机组开发商,同时开发两种机型方能更好地适应市场的竞争。

  14. Minimum DNBR Prediction Using Artificial Intelligence

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Su; Kim, Ju Hyun; Na, Man Gyun [Chosun University, Gwangju (Korea, Republic of)

    2011-05-15

    The minimum DNBR (MDNBR) for prevention of the boiling crisis and the fuel clad melting is very important factor that should be consistently monitored in safety aspects. Artificial intelligence methods have been extensively and successfully applied to nonlinear function approximation such as the problem in question for predicting DNBR values. In this paper, support vector regression (SVR) model and fuzzy neural network (FNN) model are developed to predict the MDNBR using a number of measured signals from the reactor coolant system. Also, two models are trained using a training data set and verified against test data set, which does not include training data. The proposed MDNBR estimation algorithms were verified by using nuclear and thermal data acquired from many numerical simulations of the Yonggwang Nuclear Power Plant Unit 3 (YGN-3)

  15. Charge identification of highly ionizing particles in desensitized nuclear emulsion using high speed read-out system

    International Nuclear Information System (INIS)

    Toshito, T.; Kodama, K.; Yusa, K.; Ozaki, M.; Amako, K.; Kameoka, S.; Murakami, K.; Sasaki, T.; Aoki, S.; Ban, T.; Fukuda, T.; Naganawa, N.; Nakamura, T.; Natsume, M.; Niwa, K.; Takahashi, S.; Kanazawa, M.; Kanematsu, N.; Komori, M.; Sato, S.; Asai, M.; Koi, T.; Fukushima, C.; Ogawa, S.; Shibasaki, M.; Shibuya, H.

    2006-01-01

    We performed an experimental study of charge identification of heavy ions from helium to carbon having energy of about 290MeV/u using an emulsion chamber. Emulsion was desensitized by means of forced fading (refreshing) to expand a dynamic range of response to highly charged particles. For the track reconstruction and charge identification, the fully automated high speed emulsion read-out system, which was originally developed for identifying minimum ionizing particles, was used without any modification. Clear track by track charge identification up to Z=6 was demonstrated. The refreshing technique has proved to be a powerful technique to expand response of emulsion film to highly ionizing particles

  16. A Harmonic Resonance Suppression Strategy for a High-Speed Railway Traction Power Supply System with a SHE-PWM Four-Quadrant Converter Based on Active-Set Secondary Optimization

    Directory of Open Access Journals (Sweden)

    Runze Zhang

    2017-10-01

    Full Text Available Pulse width modulation (PWM technology is widely used in traction converters for high-speed railways. The harmonic distribution caused by PWM is quite extensive, and increases the possibility of grid–train coupling resonance in the traction power supply system (TPSS. This paper first analyzes the mechanism of resonance, when the characteristic harmonic frequency of a four-quadrant converter (4QC current that injects into the traction grid matches the resonant frequency of the traction grid, which may result in resonance in the system. To suppress resonance, this paper adopts specific harmonic elimination–pulse width modulation (SHE-PWM technology combined with a transient direct current control strategy to eliminate the harmonics in the resonant frequency, which may suppress the grid–train coupling resonance. Due to the fact that the SHE-PWM process with multiple switching angles contains complex transcendental equations, the initial value is difficult to provide, and is difficult to solve using ordinary iterative algorithms. In this paper, an active-set secondary optimization method is used to solve the equation. The algorithm has the benefits of low dependence on initial values, fast convergence and high solution accuracy. Finally, the feasibility of the resonant suppression algorithm is verified by means of Matlab simulation.

  17. Speed and income

    DEFF Research Database (Denmark)

    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....

  18. Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

    Directory of Open Access Journals (Sweden)

    Yanting Hu

    2013-07-01

    Full Text Available Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG developed in the simulation tool of PSCAD/EMTDC. Flicker emission of this system is investigated. The 3p (three times per revolution power oscillation due to wind shear and tower shadow effects is the significant part in the flicker emission of variable speed wind turbines with PMSG during continuous operation. A new method of flicker mitigation by controlling the rotational speed is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the rotational speed of the PMSG. Simulation results show that damping the 3p active power oscillation by using the flicker mitigation speed controller is an effective means for flicker mitigation of variable speed wind turbines with full-scale back-to-back power converters and PMSG during continuous operation.

  19. Minimum airflow reset of single-duct VAV terminal boxes

    Science.gov (United States)

    Cho, Young-Hum

    Single duct Variable Air Volume (VAV) systems are currently the most widely used type of HVAC system in the United States. When installing such a system, it is critical to determine the minimum airflow set point of the terminal box, as an optimally selected set point will improve the level of thermal comfort and indoor air quality (IAQ) while at the same time lower overall energy costs. In principle, this minimum rate should be calculated according to the minimum ventilation requirement based on ASHRAE standard 62.1 and maximum heating load of the zone. Several factors must be carefully considered when calculating this minimum rate. Terminal boxes with conventional control sequences may result in occupant discomfort and energy waste. If the minimum rate of airflow is set too high, the AHUs will consume excess fan power, and the terminal boxes may cause significant simultaneous room heating and cooling. At the same time, a rate that is too low will result in poor air circulation and indoor air quality in the air-conditioned space. Currently, many scholars are investigating how to change the algorithm of the advanced VAV terminal box controller without retrofitting. Some of these controllers have been found to effectively improve thermal comfort, indoor air quality, and energy efficiency. However, minimum airflow set points have not yet been identified, nor has controller performance been verified in confirmed studies. In this study, control algorithms were developed that automatically identify and reset terminal box minimum airflow set points, thereby improving indoor air quality and thermal comfort levels, and reducing the overall rate of energy consumption. A theoretical analysis of the optimal minimum airflow and discharge air temperature was performed to identify the potential energy benefits of resetting the terminal box minimum airflow set points. Applicable control algorithms for calculating the ideal values for the minimum airflow reset were developed and

  20. High speed atom source

    International Nuclear Information System (INIS)

    Hoshino, Hitoshi.

    1990-01-01

    In a high speed atom source, since the speed is not identical between ions and electrons, no sufficient neutralizing effect for ionic rays due to the mixing of the ionic rays and the electron rays can be obtained failing to obtain high speed atomic rays at high density. In view of the above, a speed control means is disposed for equalizing the speed of ions forming ionic rays and the speed of electrons forming electron rays. Further, incident angle of the electron rays and/or ionic rays to a magnet or an electrode is made variable. As a result, the relative speed between the ions and the electrons to the processing direction is reduced to zero, in which the probability of association between the ions and the electrons due to the coulomb force is increased to improve the neutralizing efficiency to easily obtain fine and high density high speed electron rays. Further, by varying the incident angle, a track capable of obtaining an ideal mixing depending on the energy of the neutralized ionic rays is formed. Since the high speed electron rays has such high density, they can be irradiated easily to the minute region of the specimen. (N.H.)

  1. Computer ray tracing speeds.

    Science.gov (United States)

    Robb, P; Pawlowski, B

    1990-05-01

    The results of measuring the ray trace speed and compilation speed of thirty-nine computers in fifty-seven configurations, ranging from personal computers to super computers, are described. A correlation of ray trace speed has been made with the LINPACK benchmark which allows the ray trace speed to be estimated using LINPACK performance data. The results indicate that the latest generation of workstations, using CPUs based on RISC (Reduced Instruction Set Computer) technology, are as fast or faster than mainframe computers in compute-bound situations.

  2. The minimum yield in channeling

    International Nuclear Information System (INIS)

    Uguzzoni, A.; Gaertner, K.; Lulli, G.; Andersen, J.U.

    2000-01-01

    A first estimate of the minimum yield was obtained from Lindhard's theory, with the assumption of a statistical equilibrium in the transverse phase-space of channeled particles guided by a continuum axial potential. However, computer simulations have shown that this estimate should be corrected by a fairly large factor, C (approximately equal to 2.5), called the Barrett factor. We have shown earlier that the concept of a statistical equilibrium can be applied to understand this result, with the introduction of a constraint in phase-space due to planar channeling of axially channeled particles. Here we present an extended test of these ideas on the basis of computer simulation of the trajectories of 2 MeV α particles in Si. In particular, the gradual trend towards a full statistical equilibrium is studied. We also discuss the introduction of this modification of standard channeling theory into descriptions of the multiple scattering of channeled particles (dechanneling) by a master equation and show that the calculated minimum yields are in very good agreement with the results of a full computer simulation

  3. Minimum Bias Trigger in ATLAS

    International Nuclear Information System (INIS)

    Kwee, Regina

    2010-01-01

    Since the restart of the LHC in November 2009, ATLAS has collected inelastic pp collisions to perform first measurements on charged particle densities. These measurements will help to constrain various models describing phenomenologically soft parton interactions. Understanding the trigger efficiencies for different event types are therefore crucial to minimize any possible bias in the event selection. ATLAS uses two main minimum bias triggers, featuring complementary detector components and trigger levels. While a hardware based first trigger level situated in the forward regions with 2.2 < |η| < 3.8 has been proven to select pp-collisions very efficiently, the Inner Detector based minimum bias trigger uses a random seed on filled bunches and central tracking detectors for the event selection. Both triggers were essential for the analysis of kinematic spectra of charged particles. Their performance and trigger efficiency measurements as well as studies on possible bias sources will be presented. We also highlight the advantage of these triggers for particle correlation analyses. (author)

  4. Deterministic prediction of surface wind speed variations

    Directory of Open Access Journals (Sweden)

    G. V. Drisya

    2014-11-01

    Full Text Available Accurate prediction of wind speed is an important aspect of various tasks related to wind energy management such as wind turbine predictive control and wind power scheduling. The most typical characteristic of wind speed data is its persistent temporal variations. Most of the techniques reported in the literature for prediction of wind speed and power are based on statistical methods or probabilistic distribution of wind speed data. In this paper we demonstrate that deterministic forecasting methods can make accurate short-term predictions of wind speed using past data, at locations where the wind dynamics exhibit chaotic behaviour. The predictions are remarkably accurate up to 1 h with a normalised RMSE (root mean square error of less than 0.02 and reasonably accurate up to 3 h with an error of less than 0.06. Repeated application of these methods at 234 different geographical locations for predicting wind speeds at 30-day intervals for 3 years reveals that the accuracy of prediction is more or less the same across all locations and time periods. Comparison of the results with f-ARIMA model predictions shows that the deterministic models with suitable parameters are capable of returning improved prediction accuracy and capturing the dynamical variations of the actual time series more faithfully. These methods are simple and computationally efficient and require only records of past data for making short-term wind speed forecasts within practically tolerable margin of errors.

  5. Critical Speed Control for a Fixed Blade Variable Speed Wind Turbine

    Directory of Open Access Journals (Sweden)

    Morgan Rossander

    2017-10-01

    Full Text Available A critical speed controller for avoiding a certain rotational speed is presented. The controller is useful for variable speed wind turbines with a natural frequency in the operating range. The controller has been simulated, implemented and tested on an open site 12 kW vertical axis wind turbine prototype. The controller is based on an adaptation of the optimum torque control. Two lookup tables and a simple state machine provide the control logic of the controller. The controller requires low computational resources, and no wind speed measurement is needed. The results suggest that the controller is a feasible method for critical speed control. The skipping behavior can be adjusted using only two parameters. While tested on a vertical axis wind turbine, it may be used on any variable speed turbine with the control of generator power.

  6. Endurance in speed skating

    NARCIS (Netherlands)

    Kuper, G.H.; Sterken, E.

    2002-01-01

    We analyse the development of world records speed skating from 1893 to 2000 for bothmen and women. The historical data show that it is likely that the relation betweenskating speed and distance of the various events is non-linear and converges to a limitvalue. We pay special attention to technical

  7. Endurance in speed skating

    NARCIS (Netherlands)

    Kuper, Gerard H.; Sterken, Elmer

    2001-01-01

    We analyse the development of world records speed skating from 1893 to 2000 for both men and women. The historical data show that it is likely that the relation between skating speed and distance of the various events is non-linear and converges to a limit value. We pay special attention to

  8. Effectiveness of Motorcycle speed controlled by speed hump

    Directory of Open Access Journals (Sweden)

    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.

  9. Study on a constant-tip-speed-ratio operation of wind power generation system. Effect of load control system on dynamic behavior; Furyoku hatsuden system no hensoku seigyo unten ni kansuru kenkyu. Fuka seigyokei ga system no rikigakuteki kyodo ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Wakui, T.; Yamaguchi, K. [Waseda University, Tokyo (Japan); Tanzawa, Y. [Nippon Institute of Technology, Saitama (Japan); Hashizume, T.; Ota, E. [Waseda University, Tokyo (Japan). School of Science and Engineering

    1998-06-01

    The effect that the set data of the load control system in a wind power generation system exerts on the dynamic behavior of a system was investigated. The wind power generation system consists of a hybrid wind turbine with combined Darrieus and Savonius rotors, load with a generator and battery in the center, and a controller. A constant-tip-speed ratio operation that holds the circumferential speed ratio in which the power coefficient is maximized irrespective of the change in wind velocity was used to extract and convert the wind energy more effectively. In a high-wind velocity area, the system is operated at a fixed speed, and the increase in rotation is suppressed to protect the wing strength. In a large system, the response characteristics are only slightly improved by the limited load operation range and influenced rotor inertial. Power cannot be fully extracted even if the control system is changed in setting, and the applicability to the wind situation remains low. During the actual operation, the adjustment value of the control system should be set so that the output operation is satisfactorily possible in the specified load operation range, that is, the change in the instantaneous value of an effective power coefficient indicates almost flat gain characteristics in frequency characteristics. 14 refs., 10 figs., 2 tabs.

  10. Solar wind and coronal structure near sunspot minimum - Pioneer and SMM observations from 1985-1987

    Science.gov (United States)

    Mihalov, J. D.; Barnes, A.; Hundhausen, A. J.; Smith, E. J.

    1990-01-01

    Changes in solar wind speed and magnetic polarity observed at the Pioneer spacecraft are discussed here in terms of the changing magnetic geometry implied by SMM coronagraph observations over the period 1985-1987. The pattern of recurrent solar wind streams, the long-term average speed, and the sector polarity of the interplanetary magnetic field all changed in a manner suggesting both a temporal variation, and a changing dependence on heliographic latitude. Coronal observations during this epoch show a systematic variation in coronal structure and the magnetic structure imposed on the expanding solar wind. These observations suggest interpretation of the solar wind speed variations in terms of the familiar model where the speed increases with distance from a nearly flat interplanetary current sheet, and where this current sheet becomes aligned with the solar equatorial plane as sunspot minimum approaches, but deviates rapidly from that orientation after minimum.

  11. Mathematical game type optimization of powerful fast reactors

    International Nuclear Information System (INIS)

    Pavelesku, M.; Dumitresku, Kh.; Adam, S.

    1975-01-01

    To obtain maximum speed of putting into operation fast breeders it is recommended on the initial stage of putting into operation these reactors to apply lower power which needs less fission materials. That is why there is an attempt to find a configuration of a high-power reactor providing maximum power for minimum mass of fission material. This problem has a structure of the mathematical game with two partners of non-zero-order total and is solved by means of specific aids of theory of games. Optimal distribution of fission and breeding materials in a multizone reactor first is determined by solution of competitive game and then, on its base, by solution of the cooperation game. The second problem the solution for which is searched is developed from remark on the fact that a reactor with minimum coefficient of flux heterogenity has a configuration different from the reactor with power coefficient heterogenity. Maximum burn-up of fuel needs minimum heterogenity of the flux coefficient and the highest power level needs minimum coefficient of power heterogenity. That is why it is possible to put a problem of finding of the reactor configuration having both coefficients with minimum value. This problem has a structure of a mathematical game with two partners of non-zero-order total and is solved analogously giving optimal distribution of fuel from the new point of view. In the report is shown that both these solutions are independent which is a result of the aim put in the problem of optimization. (author)

  12. Minimum Delay Moving Object Detection

    KAUST Repository

    Lao, Dong

    2017-11-09

    We present a general framework and method for detection of an object in a video based on apparent motion. The object moves relative to background motion at some unknown time in the video, and the goal is to detect and segment the object as soon it moves in an online manner. Due to unreliability of motion between frames, more than two frames are needed to reliably detect the object. Our method is designed to detect the object(s) with minimum delay, i.e., frames after the object moves, constraining the false alarms. Experiments on a new extensive dataset for moving object detection show that our method achieves less delay for all false alarm constraints than existing state-of-the-art.

  13. Approximating the minimum cycle mean

    Directory of Open Access Journals (Sweden)

    Krishnendu Chatterjee

    2013-07-01

    Full Text Available We consider directed graphs where each edge is labeled with an integer weight and study the fundamental algorithmic question of computing the value of a cycle with minimum mean weight. Our contributions are twofold: (1 First we show that the algorithmic question is reducible in O(n^2 time to the problem of a logarithmic number of min-plus matrix multiplications of n-by-n matrices, where n is the number of vertices of the graph. (2 Second, when the weights are nonnegative, we present the first (1 + ε-approximation algorithm for the problem and the running time of our algorithm is ilde(O(n^ω log^3(nW/ε / ε, where O(n^ω is the time required for the classic n-by-n matrix multiplication and W is the maximum value of the weights.

  14. Minimum Delay Moving Object Detection

    KAUST Repository

    Lao, Dong

    2017-01-08

    We present a general framework and method for detection of an object in a video based on apparent motion. The object moves relative to background motion at some unknown time in the video, and the goal is to detect and segment the object as soon it moves in an online manner. Due to unreliability of motion between frames, more than two frames are needed to reliably detect the object. Our method is designed to detect the object(s) with minimum delay, i.e., frames after the object moves, constraining the false alarms. Experiments on a new extensive dataset for moving object detection show that our method achieves less delay for all false alarm constraints than existing state-of-the-art.

  15. Minimum Delay Moving Object Detection

    KAUST Repository

    Lao, Dong; Sundaramoorthi, Ganesh

    2017-01-01

    We present a general framework and method for detection of an object in a video based on apparent motion. The object moves relative to background motion at some unknown time in the video, and the goal is to detect and segment the object as soon it moves in an online manner. Due to unreliability of motion between frames, more than two frames are needed to reliably detect the object. Our method is designed to detect the object(s) with minimum delay, i.e., frames after the object moves, constraining the false alarms. Experiments on a new extensive dataset for moving object detection show that our method achieves less delay for all false alarm constraints than existing state-of-the-art.

  16. Youth minimum wages and youth employment

    NARCIS (Netherlands)

    Marimpi, Maria; Koning, Pierre

    2018-01-01

    This paper performs a cross-country level analysis on the impact of the level of specific youth minimum wages on the labor market performance of young individuals. We use information on the use and level of youth minimum wages, as compared to the level of adult minimum wages as well as to the median

  17. Do Some Workers Have Minimum Wage Careers?

    Science.gov (United States)

    Carrington, William J.; Fallick, Bruce C.

    2001-01-01

    Most workers who begin their careers in minimum-wage jobs eventually gain more experience and move on to higher paying jobs. However, more than 8% of workers spend at least half of their first 10 working years in minimum wage jobs. Those more likely to have minimum wage careers are less educated, minorities, women with young children, and those…

  18. Does the Minimum Wage Affect Welfare Caseloads?

    Science.gov (United States)

    Page, Marianne E.; Spetz, Joanne; Millar, Jane

    2005-01-01

    Although minimum wages are advocated as a policy that will help the poor, few studies have examined their effect on poor families. This paper uses variation in minimum wages across states and over time to estimate the impact of minimum wage legislation on welfare caseloads. We find that the elasticity of the welfare caseload with respect to the…

  19. Minimum income protection in the Netherlands

    NARCIS (Netherlands)

    van Peijpe, T.

    2009-01-01

    This article offers an overview of the Dutch legal system of minimum income protection through collective bargaining, social security, and statutory minimum wages. In addition to collective agreements, the Dutch statutory minimum wage offers income protection to a small number of workers. Its

  20. Iceland blasts millennium bugs in speed governors

    Energy Technology Data Exchange (ETDEWEB)

    Gislason, Gisli [Landsvirkjun, Reykjavik (Iceland). Electromechanical Dept.; Ferme, J.-M. [Voith Hydro, Heidenheim (Germany)

    1999-11-01

    This article focuses on the examination of distribution management systems to identify any potential problems related to the year 2000 (Y2K) that would affect the operation of speed governors with date management capacity at Iceland's hydroelectric power plants. Details are given of the work carried out by Landsvirkjun, Iceland's main power generator, the use of date for monitoring functions, the different governor models, the testing of the digital speed governors, and the modification of software in cases where protection relays were untestable.

  1. Minimum intensity projection technique in the evaluation of pulmonary emphysema

    International Nuclear Information System (INIS)

    Ishii, Chikako; Tada, Shinpei; Fukuda, Kunihiko; Hayashi, Naganobu

    2000-01-01

    Clinically diagnosed 30 pulmonary emphysema patients were evaluated with helical CT. From 10 mm thickness and 10 mm/sec table speed helical CT date set, minimum intensity projection (Min-IP) were generated. Min-IP coronal images were well demonstrated distribution and degree of emphysema. Compared to the high resolution CT images (2 mm thickness), Min-IP images were as same as well evaluated the disease. Min-IP technique seem to be useful for evaluate distribution and degree of pulmonary emphysema. (author)

  2. Application of the minimum fuel neural network to music signals

    DEFF Research Database (Denmark)

    Harbo, Anders La-Cour

    2004-01-01

    ) for finding sparse representations of music signals. This method is a set of two ordinary differential equations. We argue that the most important parameter for optimal use of this method is the discretization step size, and we demonstrate that this can be a priori determined. This significantly speeds up......Finding an optimal representation of a signal in an over-complete dictionary is often quite difficult. Since general results in this field are not very application friendly it truly helps to specify the framework as much as possible. We investigate the method Minimum Fuel Neural Network (MFNN...

  3. Variable speed control for Vertical Axis Wind Turbine

    DEFF Research Database (Denmark)

    Galinos, Christos; Larsen, Torben J.

    A robust variable speed control for vertical axis wind turbine applications is implemented. It is a PI rotor speed controller based on an induction generator model operated at variable frequency. The generator dynamics are approximated by a first order differential equation with a prescribed slip....... In order to allow variability in the rotor speed an inverter is assumed which changes the nominal generator speed. Below rated power the optimum tip speed ratio is tracked, while above the power is constrained to rated. The wind speed which is needed in the control it is considered as a known signal...... the Inflow project. The investigation of the VAWT performance under different control parameters such as the PI gains has been performed by Christos Galinos. Deterministic and turbulent wind speed steps of 2 m/s from 6 m/s to 24 m/s and back to 12 m/s are applied. The controller gives smooth transient...

  4. Traffic speed management

    Directory of Open Access Journals (Sweden)

    Subotić Jovana Lj.

    2014-01-01

    Full Text Available Speed, and vehicles themselves, affect the level of service and road safety, quality of life, noise from traffic, the environment, health, air pollution, emission of carbon dioxide, global warming, the economy and consumption of non-renewable energy such as oil. Therefore, the speed management of the traffic of multiple significance and that should be primarily to provide effective and economical conditions of the modern and preventive protection of human life as the greatest treasure and then the material resources. The way to accomplish this is by using various (different measures such as: appropriate planning and projecting roads and streets, speed control, the legislation, enforcement, campaigns, education, advanced technologies (ITS.

  5. High-speed elevators controlled by inverters

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Yoshio; Takahashi, Hideaki; Nakamura, Kiyoshi; Kinoshita, Hiroshi

    1988-10-25

    The super-high-speed elevator with superiority to 300m/min of speed, requires both the large capacity power and wide range speed controls. Therefore, in order to materialize the smooth and quiet operation characteristics, by applying the inverter control, the low torque ripple control in the low frequency range and high frequency large capacity inverting for lowering the motor in noise are necessary with their being assured of reliability. To satisfy the above necessary items, together with the development of a sine wave pulse width and frequency modulation (PWM/PFM) control system, to more precisely enable the sine wave electric current control, and 3kHz switching power converter, using a 800A power transistor module, a supervoltage control circuit under the extraordinary condition was designed. As a result of commercializing a 360m/min super-high speed inverter elevator, the power source unit, due to the effect of high power factor, could be reduced by 30% in capacity and also the higher harmonic wave including ratio could be considerably lowered to the inferiority to 5%. 2 references, 7 figures, 1 table.

  6. Minimum wage development in the Russian Federation

    OpenAIRE

    Bolsheva, Anna

    2012-01-01

    The aim of this paper is to analyze the effectiveness of the minimum wage policy at the national level in Russia and its impact on living standards in the country. The analysis showed that the national minimum wage in Russia does not serve its original purpose of protecting the lowest wage earners and has no substantial effect on poverty reduction. The national subsistence minimum is too low and cannot be considered an adequate criterion for the setting of the minimum wage. The minimum wage d...

  7. Utilization of excess wind power in electric vehicles

    International Nuclear Information System (INIS)

    Hennings, Wilfried; Mischinger, Stefan; Linssen, Jochen

    2013-01-01

    This article describes the assessment of future wind power utilization for charging electric vehicles (EVs) in Germany. The potential wind power production in the model years 2020 and 2030 is derived by extrapolating onshore wind power generation and offshore wind speeds measured in 2007 and 2010 to the installed onshore and offshore wind turbine capacities assumed for 2020 and 2030. The energy consumption of an assumed fleet of 1 million EVs in 2020 and 6 million in 2030 is assessed using detailed models of electric vehicles, real world driving cycles and car usage. It is shown that a substantial part of the charging demand of EVs can be met by otherwise unused wind power, depending on the amount of conventional power required for stabilizing the grid. The utilization of wind power is limited by the charging demand of the cars and the bottlenecks in the transmission grid. -- Highlights: •Wind power available for charging depends on minimum required conventional power (must-run). •With 20 GW must-run power, 50% of charging can be met by excess wind power. •Grid bottlenecks decrease charging met by wind power from 50 % to 30 %. •With zero must-run power, only very little wind power is available for charging

  8. Applicability of the minimum entropy generation method for optimizing thermodynamic cycles

    Institute of Scientific and Technical Information of China (English)

    Cheng Xue-Tao; Liang Xin-Gang

    2013-01-01

    Entropy generation is often used as a figure of merit in thermodynamic cycle optimizations.In this paper,it is shown that the applicability of the minimum entropy generation method to optimizing output power is conditional.The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power when the total heat into the system of interest is not prescribed.For the cycles whose working medium is heated or cooled by streams with prescribed inlet temperatures and prescribed heat capacity flow rates,it is theoretically proved that both the minimum entropy generation rate and the minimum entropy generation number correspond to the maximum output power when the virtual entropy generation induced by dumping the used streams into the environment is considered.However,the minimum principle of entropy generation is not tenable in the case that the virtual entropy generation is not included,because the total heat into the system of interest is not fixed.An irreversible Carnot cycle and an irreversible Brayton cycle are analysed.The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power if the heat into the system of interest is not prescribed.

  9. Applicability of the minimum entropy generation method for optimizing thermodynamic cycles

    International Nuclear Information System (INIS)

    Cheng Xue-Tao; Liang Xin-Gang

    2013-01-01

    Entropy generation is often used as a figure of merit in thermodynamic cycle optimizations. In this paper, it is shown that the applicability of the minimum entropy generation method to optimizing output power is conditional. The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power when the total heat into the system of interest is not prescribed. For the cycles whose working medium is heated or cooled by streams with prescribed inlet temperatures and prescribed heat capacity flow rates, it is theoretically proved that both the minimum entropy generation rate and the minimum entropy generation number correspond to the maximum output power when the virtual entropy generation induced by dumping the used streams into the environment is considered. However, the minimum principle of entropy generation is not tenable in the case that the virtual entropy generation is not included, because the total heat into the system of interest is not fixed. An irreversible Carnot cycle and an irreversible Brayton cycle are analysed. The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power if the heat into the system of interest is not prescribed. (general)

  10. Characterization of RNS multiply-add units for power efficient DSP

    DEFF Research Database (Denmark)

    Cardarilli, Gian Carlo; Nannarelli, Alberto; Petricca, Massimo

    2015-01-01

    ) for a fused multiply-add unit by taking into account four metrics: area, delay, power consumption, and switching activity. The results of the DSE are verified against the TCS and RNS implementation of parallel FIR filters of different characteristics. In both the DSE and the filter implementation, we consider......In the past decades, the Residue Number System (RNS) has been adopted in DSP as an alternative to the traditional two's complement number system (TCS) because of the savings in area, higher speed and reduced power dissipation. In this work, we perform a comprehensive Design Space Exploration (DSE...... two design corners: maximum speed and minimum area. The experimental results demonstrate that for high data rates and high order filters, the RNS implementation is more power efficient than the TCS because of the reduced switching activity and the larger amount of low-power cells placed in the unit....

  11. High-Speed Photography

    International Nuclear Information System (INIS)

    Paisley, D.L.; Schelev, M.Y.

    1998-01-01

    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 1998 Society of Photo-Optical Instrumentation Engineers

  12. Wind_Speeds_Master

    Data.gov (United States)

    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...

  13. High speed data acquisition

    International Nuclear Information System (INIS)

    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

  14. Results in energy saving obtained with the application of speed variator in fossil power stations; Resultados de ahorro de energia obtenidos con la aplicacion de variadores de velocidad en centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Merlos Rueda, Rosa Maria [Programa de Ahorro de Energia del Sector Electrico (PAESE), Mexico, D. F. (Mexico)

    1999-07-01

    The project of installation of speed variator in fossil power stations (CT's) of Comision Federal de Electricidad (CFE), as an energy saving measure, is a pilot project that began with the support of the Subdivision de Generacion, and promoted by the Energy Saving Program of the Electric Sector (PAESE), with the putting in operation of an equipment in the condensate pump of the Punta Prieta II C. T. U3. The energy saving observed was substantial, fluctuating between the 19.4% at high loads (at 90% load) and the 71.1% at low loads (at 40% load) of the generating unit. With these results, it was decided to extend the scope of the project with the installation of 6 more equipment for equal number of fossil power stations, located in 4 of the 5 Regions of Generation. The fossil power stations, selected for this stage of the project were: C. T. Felipe Carrillo Puerto U1, C.T. Lerma U4, C.T. Salamanca U1, C.T. Monterrey U6, C.T. Francisco Villa U3 and the C.T. Punta Prieta II-U1. The equipment was in operation during the first quarter of 1998, and the first results indicate an energy savings average per equipment, between 39% and 52%. The recovery of the investment fluctuates between the 48.4% and the 87.6% in less than two years of operation, with which a maximum period of recovery of 3 years is expected. The estimated potential of energy saving, considering the application of these devices in condensate pumps, feedwater pumps (where no speed variator is installed) forced draft fans, induced draft fans and gas recirculation fans, as well as circulation water pumps, of the existing Generating Power stations, ascends to an annual total of 830,000, which represents an approximate 9.4% of the National consumption of self services. [Spanish] El proyecto de instalacion de variadores de velocidad en Centrales Termoelectricas (CT's) de la Comision Federal de Electricidad (CFE), como medida de ahorro de energia, es un proyecto piloto que se inicio con el apoyo de la

  15. Time-limited optimal dynamics beyond the Quantum Speed Limit

    DEFF Research Database (Denmark)

    Gajdacz, Miroslav; Das, Kunal K.; Arlt, Jan

    2015-01-01

    The quantum speed limit sets the minimum time required to transfer a quantum system completely into a given target state. At shorter times the higher operation speed has to be paid with a loss of fidelity. Here we quantify the trade-off between the fidelity and the duration in a system driven......-off expressed in terms of the direct Hilbert velocity provides a robust prediction of the quantum speed limit and allows to adapt the control optimization such that it yields a predefined fidelity. The results are verified numerically in a multilevel system with a constrained Hamiltonian, and a classification...

  16. Option of operating speed for vessels under low-carbon economy

    Directory of Open Access Journals (Sweden)

    Gang Li

    2013-03-01

    Full Text Available Purpose: To find out ships' optimum operating speed under low-carbon economy. Approach: First, it analyzes the relations between ship’s carbon emission and the operating speed, gets the optimum speed under which the entire fleet emit minimum carbon, then establishes the relations between the ship owner’s profit and the speed, extracts the speed under which the ship owner can gain the maximum profit and founds out it’s different from the speed under which the entire fleet emit minimum carbon. Findings: The government must take effective measures to make the ship owner slowdown and reduce emission. Originality: It first works out a balance point between the decrease of carbon emission brought by a lower operating speed and the increase of that caused by more vessels putting into service in a mathematical method.

  17. Minimum Delay Moving Object Detection

    KAUST Repository

    Lao, Dong

    2017-05-14

    This thesis presents a general framework and method for detection of an object in a video based on apparent motion. The object moves, at some unknown time, differently than the “background” motion, which can be induced from camera motion. The goal of proposed method is to detect and segment the object as soon it moves in an online manner. Since motion estimation can be unreliable between frames, more than two frames are needed to reliably detect the object. Observing more frames before declaring a detection may lead to a more accurate detection and segmentation, since more motion may be observed leading to a stronger motion cue. However, this leads to greater delay. The proposed method is designed to detect the object(s) with minimum delay, i.e., frames after the object moves, constraining the false alarms, defined as declarations of detection before the object moves or incorrect or inaccurate segmentation at the detection time. Experiments on a new extensive dataset for moving object detection show that our method achieves less delay for all false alarm constraints than existing state-of-the-art.

  18. Adjustable speed drive study, part 1

    Science.gov (United States)

    Wallace, A.

    1989-08-01

    Advances in speed control for motors in recent years, notably those in power electronics, have widened the range of application for several adjustable speed drive (ASD) types to include the smaller horsepower sizes. The dc motor drive, formerly in almost universal use for speed control, is being challenged by the high efficiency induction motor/pulse width modulation (PWM) drive; and for special small horsepower size applications, by the permanent magnet motor/PWM inverter drive or by the switched reluctance motor drive. The main characteristics of the several ASD types suitable for small horsepower size applications are discussed, as well as their unwanted side effects: poor power factor, harmonic distortion of the supply, acoustic noise, and electromagnetic interference. A procedure is recommended for determining which, if any, ASD to use.

  19. Latitude dependence of the solar wind speed: Influence of the coronal magnetic field geometry

    International Nuclear Information System (INIS)

    Pneuman, G.W.

    1976-01-01

    The dependence of solar wind speed on latitude as influenced by the magnetic field configuration of the inner corona is studied. It is found that in general, a dipolelike field geometry characteristic of a minimum-type corona tends to produce a solar wind speed distribution which increases with heliographic latitude, in accordance with observations. At very high coronal base densities and temperatures, however, this effect is minimal or even inverted. Physically, the field affects the wind speed through its area divergence, a larger divergence resulting in correspondingly lower speeds. During solar minimum, eclipse photographs suggest that the field divergence increases from pole to equator, a characteristic not apparent during solar maximum. Hence we expect the latitudinal increase in speed to be most pronounced at the minimum phase of solar activity

  20. Minimum Additive Waste Stabilization (MAWS)

    International Nuclear Information System (INIS)

    1994-02-01

    In the Minimum Additive Waste Stabilization(MAWS) concept, actual waste streams are utilized as additive resources for vitrification, which may contain the basic components (glass formers and fluxes) for making a suitable glass or glassy slag. If too much glass former is present, then the melt viscosity or temperature will be too high for processing; while if there is too much flux, then the durability may suffer. Therefore, there are optimum combinations of these two important classes of constituents depending on the criteria required. The challenge is to combine these resources in such a way that minimizes the use of non-waste additives yet yields a processable and durable final waste form for disposal. The benefit to this approach is that the volume of the final waste form is minimized (waste loading maximized) since little or no additives are used and vitrification itself results in volume reduction through evaporation of water, combustion of organics, and compaction of the solids into a non-porous glass. This implies a significant reduction in disposal costs due to volume reduction alone, and minimizes future risks/costs due to the long term durability and leach resistance of glass. This is accomplished by using integrated systems that are both cost-effective and produce an environmentally sound waste form for disposal. individual component technologies may include: vitrification; thermal destruction; soil washing; gas scrubbing/filtration; and, ion-exchange wastewater treatment. The particular combination of technologies will depend on the waste streams to be treated. At the heart of MAWS is vitrification technology, which incorporates all primary and secondary waste streams into a final, long-term, stabilized glass wasteform. The integrated technology approach, and view of waste streams as resources, is innovative yet practical to cost effectively treat a broad range of DOE mixed and low-level wastes